1
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Lee Y, Dai W, Towsley D, Englund D. Quantum network utility: A framework for benchmarking quantum networks. Proc Natl Acad Sci U S A 2024; 121:e2314103121. [PMID: 38640345 PMCID: PMC11047070 DOI: 10.1073/pnas.2314103121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 02/14/2024] [Indexed: 04/21/2024] Open
Abstract
The central aim of quantum networks is to facilitate user connectivity via quantum channels, but there is an open need for benchmarking metrics to compare diverse quantum networks. Here, we propose a general framework for quantifying the performance of a quantum network by estimating the value created by connecting users through quantum channels. In this framework, we define the quantum network utility metric [Formula: see text] to capture the social and economic value of quantum networks. The proposed framework accommodates a variety of applications from secure communications to distributed sensing. As a case study, we investigate the example of distributed quantum computing in detail. We determine the scaling laws of quantum network utility, which suggest that distributed edge quantum computing has more potential for success than its classical equivalent. We believe the proposed utility-based framework will serve as a foundation for guiding and assessing the development of quantum network technologies and designs.
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Affiliation(s)
- Yuan Lee
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA02139
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Wenhan Dai
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA02139
- College of Information and Computer Sciences, University of Massachusetts, Amherst, MA01003
- Quantum Photonics Laboratory, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Don Towsley
- College of Information and Computer Sciences, University of Massachusetts, Amherst, MA01003
| | - Dirk Englund
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA02139
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA02139
- Quantum Photonics Laboratory, Massachusetts Institute of Technology, Cambridge, MA02139
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2
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Ash E, Goessmann C, Naidu S. Scaling laws: legal and social complexity in US localities. Philos Trans A Math Phys Eng Sci 2024; 382:20230151. [PMID: 38403051 PMCID: PMC10894695 DOI: 10.1098/rsta.2023.0151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 12/19/2023] [Indexed: 02/27/2024]
Abstract
Law sets out the rules for society and the economy, particularly important for interactions between strangers. Legal code is a form of non-rival infrastructure, a public good important for investment and innovation. This paper investigates whether legal code complexity scales with population size in US localities. We analyse a corpus of municipal codes from 3259 cities and measure legal complexity using various metrics, including number of words, bytes, and compressed bytes. We find that legal complexity scales geometrically with jurisdiction population, with a scaling parameter of approximately 0.2 and an [Formula: see text] of approximately 0.2. The estimated scaling parameter is similar to gross domestic product per capita, consistent with an interpretation of legal codes as regulating social interactions per capita in cities. This article is part of the theme issue 'A complexity science approach to law and governance'.
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3
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Li K, Persaud D, Choudhary K, DeCost B, Greenwood M, Hattrick-Simpers J. Publisher Correction: Exploiting redundancy in large materials datasets for efficient machine learning with less data. Nat Commun 2024; 15:284. [PMID: 38177139 PMCID: PMC10767032 DOI: 10.1038/s41467-023-44462-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024] Open
Affiliation(s)
- Kangming Li
- Department of Materials Science and Engineering, University of Toronto, 27 King's College Cir, Toronto, ON, Canada
| | - Daniel Persaud
- Department of Materials Science and Engineering, University of Toronto, 27 King's College Cir, Toronto, ON, Canada
| | - Kamal Choudhary
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg, MD, USA
| | - Brian DeCost
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg, MD, USA
| | - Michael Greenwood
- Canmet MATERIALS, Natural Resources Canada, 183 Longwood Road south, Hamilton, ON, Canada
| | - Jason Hattrick-Simpers
- Department of Materials Science and Engineering, University of Toronto, 27 King's College Cir, Toronto, ON, Canada.
- Acceleration Consortium, University of Toronto, 27 King's College Cir, Toronto, ON, Canada.
- Vector Institute for Artificial Intelligence, 661 University Ave, Toronto, ON, Canada.
- Schwartz Reisman Institute for Technology and Society, 101 College St, Toronto, ON, Canada.
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4
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Gondhalekar R, Kempes CP, McGlynn SE. Scaling of Protein Function across the Tree of Life. Genome Biol Evol 2023; 15:evad214. [PMID: 38007693 PMCID: PMC10715193 DOI: 10.1093/gbe/evad214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/07/2023] [Accepted: 11/12/2023] [Indexed: 11/28/2023] Open
Abstract
Scaling laws are a powerful way to compare genomes because they put all organisms onto a single curve and reveal nontrivial generalities as genomes change in size. The abundance of functional categories across genomes has previously been found to show power law scaling with respect to the total number of functional categories, suggesting that universal constraints shape genomic category abundance. Here, we look across the tree of life to understand how genome evolution may be related to functional scaling. We revisit previous observations of functional genome scaling with an expanded taxonomy by analyzing 3,726 bacterial, 220 archaeal, and 79 unicellular eukaryotic genomes. We find that for some functional classes, scaling is best described by multiple exponents, revealing previously unobserved shifts in scaling as genome-encoded protein annotations increase or decrease. Furthermore, we find that scaling varies between phyletic groups at both the domain and phyla levels and is less universal than previously thought. This variability in functional scaling is not related to taxonomic phylogeny resolved at the phyla level, suggesting that differences in cell plan or physiology outweigh broad patterns of taxonomic evolution. Since genomes are maintained and replicated by the functional proteins encoded by them, these results point to functional degeneracy between taxonomic groups and unique evolutionary trajectories toward these. We also find that individual phyla frequently span scaling exponents of functional classes, revealing that individual clades can move across scaling exponents. Together, our results reveal unique shifts in functions across the tree of life and highlight that as genomes grow or shrink, proteins of various functions may be added or lost.
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Affiliation(s)
- Riddhi Gondhalekar
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- School of Life Sciences and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | | | - Shawn Erin McGlynn
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- School of Life Sciences and Technology, Tokyo Institute of Technology, Tokyo, Japan
- Blue Marble Space Institute of Science, Seattle, Washington, USA
- Center for Sustainable Resource Science, RIKEN, Saitama, Japan
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5
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Chimal-Eguia JC, Páez-Hernández RT, Pacheco-Paez JC, Ladino-Luna D. Linear Irreversible Thermodynamics: A Glance at Thermoelectricity and the Biological Scaling Laws. Entropy (Basel) 2023; 25:1575. [PMID: 38136455 PMCID: PMC10743106 DOI: 10.3390/e25121575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/26/2023] [Accepted: 11/08/2023] [Indexed: 12/24/2023]
Abstract
This paper presents so-called thermoelectric generators (TEGs), which are considered thermal engines that transform heat into electricity using the Seebeck effect for this purpose. By using linear irreversible thermodynamics (LIT), it is possible to study the thermodynamic properties of TEGs for three different operating regimes: maximum power output (MPO), maximum ecological function (MEF) and maximum power efficiency (MPE). Then, by considering thermoelectricty, using the correspondence between the heat capacity of a solid and the metabolic rate, and taking the generation of energy by means of the metabolism of an organism as a process out of equilibrium, it is plausible to use linear irreversible thermodynamics (LIT) to obtain some interesting results in order to understand how metabolism is generated by a particle's released energy, which explains the empirically studied allometric laws.
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Affiliation(s)
- Juan Carlos Chimal-Eguia
- Laboratorio de Ciencias Matemáticas y Computacionales, Centro de Investigación en Computacion, Instituto Politecnico Nacional, Ciudad de Mexico 07738, Mexico
| | - Ricardo Teodoro Páez-Hernández
- Area de Fisica de Procesos Irreversibles, Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana, U-Azcapotzalco, Av. San Pablo 180, Col. Reynosa, Ciudad de Mexico 02200, Mexico;
| | - Juan Carlos Pacheco-Paez
- Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-Azcapotzalco, Ciudad de Mexico 02200, Mexico;
| | - Delfino Ladino-Luna
- Area de Fisica de Procesos Irreversibles, Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana, U-Azcapotzalco, Av. San Pablo 180, Col. Reynosa, Ciudad de Mexico 02200, Mexico;
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6
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Li K, Persaud D, Choudhary K, DeCost B, Greenwood M, Hattrick-Simpers J. Exploiting redundancy in large materials datasets for efficient machine learning with less data. Nat Commun 2023; 14:7283. [PMID: 37949845 PMCID: PMC10638383 DOI: 10.1038/s41467-023-42992-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023] Open
Abstract
Extensive efforts to gather materials data have largely overlooked potential data redundancy. In this study, we present evidence of a significant degree of redundancy across multiple large datasets for various material properties, by revealing that up to 95% of data can be safely removed from machine learning training with little impact on in-distribution prediction performance. The redundant data is related to over-represented material types and does not mitigate the severe performance degradation on out-of-distribution samples. In addition, we show that uncertainty-based active learning algorithms can construct much smaller but equally informative datasets. We discuss the effectiveness of informative data in improving prediction performance and robustness and provide insights into efficient data acquisition and machine learning training. This work challenges the "bigger is better" mentality and calls for attention to the information richness of materials data rather than a narrow emphasis on data volume.
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Affiliation(s)
- Kangming Li
- Department of Materials Science and Engineering, University of Toronto, 27 King's College Cir, Toronto, ON, Canada
| | - Daniel Persaud
- Department of Materials Science and Engineering, University of Toronto, 27 King's College Cir, Toronto, ON, Canada
| | - Kamal Choudhary
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg, MD, USA
| | - Brian DeCost
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg, MD, USA
| | - Michael Greenwood
- Canmet MATERIALS, Natural Resources Canada, 183 Longwood Road south, Hamilton, ON, Canada
| | - Jason Hattrick-Simpers
- Department of Materials Science and Engineering, University of Toronto, 27 King's College Cir, Toronto, ON, Canada.
- Acceleration Consortium, University of Toronto, 27 King's College Cir, Toronto, ON, Canada.
- Vector Institute for Artificial Intelligence, 661 University Ave, Toronto, ON, Canada.
- Schwartz Reisman Institute for Technology and Society, 101 College St, Toronto, ON, Canada.
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7
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Akutsu N. Kardar-Parisi-Zhang roughening associated with nucleation-limited steady crystal growth. Sci Rep 2023; 13:16086. [PMID: 37752168 PMCID: PMC10522770 DOI: 10.1038/s41598-023-43002-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023] Open
Abstract
The roughness of crystal surfaces and the shape of crystals play important roles in multiscale phenomena. For example, the roughness of the crystal surface affects the frictional and optical properties of materials such as ice or silica. Theoretical studies on crystal surfaces based on the symmetry principle proposed that the growing surfaces of crystal growth could be classified in the universal class of Kardar-Parisi-Zhang (KPZ), but experiments rarely observe KPZ properties. To fill this the gap, extensive numerical calculations of the crystal growth rates and the surface roughness (surface width) have been performed for a nanoscale lattice model using the Monte Carlo method. The results indicate that a (001) surface is smooth within the single nucleation growth region. In contrast, the same surface is atomically smooth but thermodynamically rough in the poly-nucleation growth region in conjunction with a KPZ roughness exponent. Inclined surfaces are known to become Berezinskii-Kosterlitz-Thouless (BKT) rough surfaces both at and near equilibrium. The two types of steps associated with the (001) and (111) terraces were found to induce KPZ surface roughness, while the interplay between steps and multilayered islands promoted BKT roughness.
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Affiliation(s)
- Noriko Akutsu
- Faculty of Engineering, Osaka Electro-Communication University, Hatsu-cho, Neyagawa, Osaka, 572-8530, Japan.
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8
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Breen LI, Loveless AM, Darr AM, Cartwright KL, Garner AL. The transition from field emission to collisional space-charge limited current with nonzero initial velocity. Sci Rep 2023; 13:14505. [PMID: 37666881 PMCID: PMC10477287 DOI: 10.1038/s41598-023-41615-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 08/29/2023] [Indexed: 09/06/2023] Open
Abstract
Multiple electron emission mechanisms often contribute in electron devices, motivating theoretical studies characterizing the transitions between them. Previous studies unified thermionic and field emission, defined by the Richardson-Laue-Dushman (RLD) and Fowler-Nordheim (FN) equations, respectively, with the Child-Langmuir (CL) law for vacuum space-charge limited current (SCLC); another study unified FN and CL with the Mott-Gurney (MG) law for collisional SCLC. However, thermionic emission, which introduces a nonzero injection velocity, may also occur in gas, motivating this analysis to unify RLD, FN, CL, and MG. We exactly calculate the current density as a function of applied voltage over a range of injection velocity (i.e., temperature), mobility, and gap distance. This exact solution approaches RLD, FN, and generalized CL (GCL) and MG (GMG) for nonzero injection velocity under appropriate limits. For nonzero initial velocity, GMG approaches zero for sufficiently small applied voltage and mobility, making these gaps always space-charge limited by either GMG at low voltage or GCL at high voltage. The third-order nexus between FN, GMG, and GCL changes negligibly from the zero initial velocity calculation over ten orders of magnitude of applied voltage. These results provide a closed form solution for GMG and guidance on thermionic emission in a collisional gap.
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Affiliation(s)
- Lorin I Breen
- School of Health Sciences, Purdue University, West Lafayette, IN, 47907, USA
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Amanda M Loveless
- School of Nuclear Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Adam M Darr
- School of Nuclear Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Sandia National Laboratories, Albuquerque, NM, 87123, USA
| | | | - Allen L Garner
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 47907, USA.
- School of Nuclear Engineering, Purdue University, West Lafayette, IN, 47907, USA.
- Elmore Family School of Electrical and Computer Engineering, West Lafayette, IN, 47907, USA.
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9
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Ye Y, Lin J. Putting scaling laws on a physical foundation. eLife 2023; 12:e89415. [PMID: 37314067 DOI: 10.7554/elife.89415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023] Open
Abstract
As a cell changes size during the cell cycle, why does its density remain constant?
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Affiliation(s)
- Yiyang Ye
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Jie Lin
- Center for Quantitative Biology and the Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
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10
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Michaud EJ, Liu Z, Tegmark M. Precision Machine Learning. Entropy (Basel) 2023; 25:e25010175. [PMID: 36673316 PMCID: PMC9858077 DOI: 10.3390/e25010175] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/05/2023] [Accepted: 01/12/2023] [Indexed: 05/22/2023]
Abstract
We explore unique considerations involved in fitting machine learning (ML) models to data with very high precision, as is often required for science applications. We empirically compare various function approximation methods and study how they scale with increasing parameters and data. We find that neural networks (NNs) can often outperform classical approximation methods on high-dimensional examples, by (we hypothesize) auto-discovering and exploiting modular structures therein. However, neural networks trained with common optimizers are less powerful for low-dimensional cases, which motivates us to study the unique properties of neural network loss landscapes and the corresponding optimization challenges that arise in the high precision regime. To address the optimization issue in low dimensions, we develop training tricks which enable us to train neural networks to extremely low loss, close to the limits allowed by numerical precision.
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Affiliation(s)
- Eric J. Michaud
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- NSF AI Institute for AI and Fundamental Interactions, Cambridge, MA 02139, USA
- Correspondence:
| | - Ziming Liu
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- NSF AI Institute for AI and Fundamental Interactions, Cambridge, MA 02139, USA
| | - Max Tegmark
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- NSF AI Institute for AI and Fundamental Interactions, Cambridge, MA 02139, USA
- Center for Brains, Minds and Machines, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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11
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Ratke L, Rege A, Aney S. The Effect of Particle Necks on the Mechanical Properties of Aerogels. Materials (Basel) 2022; 16:230. [PMID: 36614567 PMCID: PMC9822111 DOI: 10.3390/ma16010230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Mechanical properties of open-porous materials are often described by constructing a cellular network with beams of constant cross sections as the struts of the cells. Such models have been applied to describe, for example, thermal and mechanical properties of aerogels. However, in many aerogels, the pore walls or the skeletal network is better described as a pearl-necklace, in which the particles making up the network appear as a string of pearls. In this paper, we investigate the effect of neck sizes on the mechanical properties of such pore walls. We present an analytical and a numerical solution by modeling these walls as corrugated beams and study the subsequent deviations from the classical scaling theory. Additionally, a full numerical model of such pearl-necklace-like walls with concave necks of varying sizes are simulated. The results of the numerical model are shown to be in good agreement with those resulting from the computational one.
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Affiliation(s)
- Lorenz Ratke
- German Aerospace Center, Institute of Materials Research, 51147 Cologne, Germany
| | - Ameya Rege
- German Aerospace Center, Institute of Materials Research, 51147 Cologne, Germany
- School of Computer Science and Mathematics, Keele University, Staffordshire ST5 5BG, UK
| | - Shivangi Aney
- German Aerospace Center, Institute of Materials Research, 51147 Cologne, Germany
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12
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Xie X, Samaei A, Guo J, Liu WK, Gan Z. Data-driven discovery of dimensionless numbers and governing laws from scarce measurements. Nat Commun 2022; 13:7562. [PMID: 36476735 DOI: 10.1038/s41467-022-35084-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 11/17/2022] [Indexed: 12/12/2022] Open
Abstract
Dimensionless numbers and scaling laws provide elegant insights into the characteristic properties of physical systems. Classical dimensional analysis and similitude theory fail to identify a set of unique dimensionless numbers for a highly multi-variable system with incomplete governing equations. This paper introduces a mechanistic data-driven approach that embeds the principle of dimensional invariance into a two-level machine learning scheme to automatically discover dominant dimensionless numbers and governing laws (including scaling laws and differential equations) from scarce measurement data. The proposed methodology, called dimensionless learning, is a physics-based dimension reduction technique. It can reduce high-dimensional parameter spaces to descriptions involving only a few physically interpretable dimensionless parameters, greatly simplifying complex process design and system optimization. We demonstrate the algorithm by solving several challenging engineering problems with noisy experimental measurements (not synthetic data) collected from the literature. Examples include turbulent Rayleigh-Bénard convection, vapor depression dynamics in laser melting of metals, and porosity formation in 3D printing. Lastly, we show that the proposed approach can identify dimensionally homogeneous differential equations with dimensionless number(s) by leveraging sparsity-promoting techniques.
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13
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Kladovasilakis N, Tsongas K, Karalekas D, Tzetzis D. Architected Materials for Additive Manufacturing: A Comprehensive Review. Materials (Basel) 2022; 15:ma15175919. [PMID: 36079300 PMCID: PMC9456607 DOI: 10.3390/ma15175919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 05/05/2023]
Abstract
One of the main advantages of Additive Manufacturing (AM) is the ability to produce topologically optimized parts with high geometric complexity. In this context, a plethora of architected materials was investigated and utilized in order to optimize the 3D design of existing parts, reducing their mass, topology-controlling their mechanical response, and adding remarkable physical properties, such as high porosity and high surface area to volume ratio. Thus, the current re-view has been focused on providing the definition of architected materials and explaining their main physical properties. Furthermore, an up-to-date classification of cellular materials is presented containing all types of lattice structures. In addition, this research summarized the developed methods that enhance the mechanical performance of architected materials. Then, the effective mechanical behavior of the architected materials was investigated and compared through the existing literature. Moreover, commercial applications and potential uses of the architected materials are presented in various industries, such as the aeronautical, automotive, biomechanical, etc. The objectives of this comprehensive review are to provide a detailed map of the existing architected materials and their mechanical behavior, explore innovative techniques for improving them and highlight the comprehensive advantages of topology optimization in industrial applications utilizing additive manufacturing and novel architected materials.
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Affiliation(s)
- Nikolaos Kladovasilakis
- Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, 57001 Thessaloniki, Greece
- Centre for Research and Technology Hellas, Information Technologies Institute (CERTH/ITI), 57001 Thessaloniki, Greece
| | - Konstantinos Tsongas
- Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, 57001 Thessaloniki, Greece
| | - Dimitris Karalekas
- Laboratory of Advanced Manufacturing Technologies and Testing, University of Piraeus, Karaoli and Dimitriou 80, 18534 Piraeus, Greece
| | - Dimitrios Tzetzis
- Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, 57001 Thessaloniki, Greece
- Correspondence:
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14
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Drivas TD, Nguyen HQ, Nobili C. Bounds on heat flux for Rayleigh-Bénard convection between Navier-slip fixed-temperature boundaries. Philos Trans A Math Phys Eng Sci 2022; 380:20210025. [PMID: 35465719 DOI: 10.1098/rsta.2021.0025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/06/2021] [Indexed: 06/14/2023]
Abstract
We study two-dimensional Rayleigh-Bénard convection with Navier-slip, fixed temperature boundary conditions and establish bounds on the Nusselt number. As the slip-length varies with Rayleigh number [Formula: see text], this estimate interpolates between the Whitehead-Doering bound by [Formula: see text] for free-slip conditions (Whitehead & Doering. 2011 Ultimate state of two-dimensional Rayleigh-Bénard convection between free-slip fixed-temperature boundaries. Phys. Rev. Lett. 106, 244501) and the classical Doering-Constantin [Formula: see text] bound (Doering & Constantin. 1996 Variational bounds on energy dissipation in incompressible flows. III. Convection. Phys. Rev. E 53, 5957-5981). This article is part of the theme issue 'Mathematical problems in physical fluid dynamics (part 1)'.
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Affiliation(s)
- Theodore D Drivas
- Department of Mathematics, Stony Brook University, Stony Brook, NY 11794, USA
| | - Huy Q Nguyen
- Department of Mathematics, University of Maryland, College Park, MD 20742, USA
| | - Camilla Nobili
- Department of Mathematics, University of Hamburg, Hamburg, Germany
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15
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Ispánovity PD, Ugi D, Péterffy G, Knapek M, Kalácska S, Tüzes D, Dankházi Z, Máthis K, Chmelík F, Groma I. Dislocation avalanches are like earthquakes on the micron scale. Nat Commun 2022; 13:1975. [PMID: 35418187 PMCID: PMC9007997 DOI: 10.1038/s41467-022-29044-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 02/16/2022] [Indexed: 11/29/2022] Open
Abstract
Compression experiments on micron-scale specimens and acoustic emission (AE) measurements on bulk samples revealed that the dislocation motion resembles a stick-slip process - a series of unpredictable local strain bursts with a scale-free size distribution. Here we present a unique experimental set-up, which detects weak AE waves of dislocation slip during the compression of Zn micropillars. Profound correlation is observed between the energies of deformation events and the emitted AE signals that, as we conclude, are induced by the collective dissipative motion of dislocations. The AE data also reveal a two-level structure of plastic events, which otherwise appear as a single stress drop. Hence, our experiments and simulations unravel the missing relationship between the properties of acoustic signals and the corresponding local deformation events. We further show by statistical analyses that despite fundamental differences in deformation mechanism and involved length- and time-scales, dislocation avalanches and earthquakes are essentially alike.
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Grants
- TKP2020-IKA-05 Emberi Eroforrások Minisztériuma (Ministry of Human Capacities)
- NKFIH-K-119561 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-FK-138975 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-K-119561 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-FK-138975 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-K-119561 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-K-119561 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-FK-138975 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- NKFIH-K-119561 Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal (NKFI Office)
- 19-22604S Grantová Agentura České Republiky (Grant Agency of the Czech Republic)
- Innovációs és Technológiai Minisztérium: ÚNKP-20-3, ÚNKP-21-4, ÚNKP-21-3
- Innovációs és Technológiai Minisztérium: ÚNKP-21-3
- Czech Science Foundation (grant No.19-22604S)
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Affiliation(s)
- Péter Dusán Ispánovity
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary.
| | - Dávid Ugi
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary.
| | - Gábor Péterffy
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary
| | - Michal Knapek
- Charles University, Faculty of Mathematics and Physics, Department of Physics of Materials, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Szilvia Kalácska
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary
- Mines Saint-Etienne, Univ Lyon, CNRS, UMR 5307 LGF, Centre SMS, 158 cours Fauriel 42023, Saint-Étienne, France
| | - Dániel Tüzes
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary
| | - Zoltán Dankházi
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary
| | - Kristián Máthis
- Charles University, Faculty of Mathematics and Physics, Department of Physics of Materials, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - František Chmelík
- Charles University, Faculty of Mathematics and Physics, Department of Physics of Materials, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - István Groma
- Eötvös Loránd University, Department of Materials Physics, Pázmány Péter sétany 1/a., 1117 Budapest, Hungary
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16
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Kanai S, Heremans FJ, Seo H, Wolfowicz G, Anderson CP, Sullivan SE, Onizhuk M, Galli G, Awschalom DD, Ohno H. Generalized scaling of spin qubit coherence in over 12,000 host materials. Proc Natl Acad Sci U S A 2022; 119:e2121808119. [PMID: 35385350 DOI: 10.1073/pnas.2121808119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Atomic defects in solid-state materials are promising candidates as quantum bits, or qubits. New materials are actively being investigated as hosts for new defect qubits; however, there are no unifying guidelines that can quantitatively predict qubit performance in a new material. One of the most critical property of qubits is their quantum coherence. While cluster correlation expansion (CCE) techniques are useful to simulate the coherence of electron spins in defects, they are computationally expensive to investigate broad classes of stable materials. Using CCE simulations, we reveal a general scaling relation between the electron spin coherence time and the properties of qubit host materials that enables rapid and quantitative exploration of new materials hosting spin defects. Spin defect centers with long quantum coherence times (T2) are key solid-state platforms for a variety of quantum applications. Cluster correlation expansion (CCE) techniques have emerged as a powerful tool to simulate the T2 of defect electron spins in these solid-state systems with good accuracy. Here, based on CCE, we uncover an algebraic expression for T2 generalized for host compounds with dilute nuclear spin baths under a magnetic field that enables a quantitative and comprehensive materials exploration with a near instantaneous estimate of the coherence time. We investigated more than 12,000 host compounds at natural isotopic abundance and found that silicon carbide (SiC), a prominent widegap semiconductor for quantum applications, possesses the longest coherence times among widegap nonchalcogenides. In addition, more than 700 chalcogenides are shown to possess a longer T2 than SiC. We suggest potential host compounds with promisingly long T2 up to 47 ms and pave the way to explore unprecedented functional materials for quantum applications.
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17
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Bec J, Krstulovic G, Matsumoto T, Ray SS, Vincenzi D. Editorial: Scaling the Turbulence Edifice. Philos Trans A Math Phys Eng Sci 2022; 380:20210101. [PMID: 35034492 PMCID: PMC8763035 DOI: 10.1098/rsta.2021.0101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Turbulence is unique in its appeal across physics, mathematics and engineering. And yet a microscopic theory, starting from the basic equations of hydrodynamics, still eludes us. In the last decade or so, new directions at the interface of physics and mathematics have emerged, which strengthens the hope of 'solving' one of the oldest problems in the natural sciences. This two-part theme issue unites these new directions on a common platform emphasizing the underlying complementarity of the physicists' and the mathematicians' approaches to a remarkably challenging problem. This article is part of the theme issue 'Scaling the turbulence edifice (part 1)'.
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Affiliation(s)
- Jérémie Bec
- Université Côte d’Azur, INRIA, CNRS, CEMEF, Sophia-Antipolis, France
- MINES ParisTech, PSL Research University, CNRS, CEMEF, Sophia-Antipolis, France
| | - Giorgio Krstulovic
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Boulevard de l’Observatoire CS 34229, NICE Cedex 4 06304, France
| | - Takeshi Matsumoto
- Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa Oiwaketyo Sakyoku, Kyoto 606-8502, Japan
| | - Samriddhi Sankar Ray
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bangalore 560089, India
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18
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Panickacheril John J, Donzis DA, Sreenivasan KR. Laws of turbulence decay from direct numerical simulations. Philos Trans A Math Phys Eng Sci 2022; 380:20210089. [PMID: 35034491 DOI: 10.1098/rsta.2021.0089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/02/2021] [Indexed: 06/14/2023]
Abstract
Inspection of available data on the decay exponent for the kinetic energy of homogeneous and isotropic turbulence (HIT) shows that it varies by as much as 100%. Measurements and simulations often show no correspondence with theoretical arguments, which are themselves varied. This situation is unsatisfactory given that HIT is a building block of turbulence theory and modelling. We take recourse to a large base of direct numerical simulations and study decaying HIT for a variety of initial conditions. We show that the Kolmogorov decay exponent and the Birkhoff-Saffman decay are both observed, albeit approximately, for long periods of time if the initial conditions are appropriately arranged. We also present, for both cases, other turbulent statistics such as the velocity derivative skewness, energy spectra and dissipation, and show that the decay and growth laws are approximately as expected theoretically, though the wavenumber spectrum near the origin begins to change relatively quickly, suggesting that the invariants do not strictly exist. We comment briefly on why the decay exponent has varied so widely in past experiments and simulations. This article is part of the theme issue 'Scaling the turbulence edifice (part 1)'.
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Affiliation(s)
- John Panickacheril John
- Department of Mechanical and Aerospace Engineering, New York University, New York, NY 10012, USA
| | - Diego A Donzis
- Department of Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Katepalli R Sreenivasan
- Department of Mechanical and Aerospace Engineering, New York University, New York, NY 10012, USA
- Department of Physics and Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
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19
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Han Z, Chen LC. Generation of Ions from Aqueous Taylor Cones near the Minimum Flow Rate: "True Nanoelectrospray" without Narrow Capillary. J Am Soc Mass Spectrom 2022; 33:491-498. [PMID: 35156376 DOI: 10.1021/jasms.1c00322] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Generating ultrafine charged droplets using electrospray is crucial for attaining high ionization efficiency for mass spectrometry. The size of the precursor charged droplets depends on the spray flow rate, and conventional wisdom holds that an electrospray of a nL/min flow rate (nanoelectrospray) is only possible using narrow capillaries with an inner diameter of ∼1 μm or smaller. Here, the electrospray of aqueous solutions with high electric conductivities generated from a large off-line capillary of 0.4 mm i.d. has been performed using a high-pressure ion source. The electric discharge is avoided by operating the ion source at 2.5 bar gauge pressure. The highly stable Taylor cone can be tuned to a near-hydrostatic state that exhibits the "true nanoelectrospray" properties, i.e., high salt tolerance and minimal ion suppression. The Q1/2 scaling law describing the electrospray current I and flow rate Q is found to be valid down to the nanoflow regime under a condition that is free of electric discharge. For a given solution, the flow rate and the size of the initial droplets and ionization species can be controlled with the spray current as the indicator for the instantaneous flow rate without changing the emitter capillary of different sizes. In regard to the application, the nanoelectrospray with a large micropipette tip is easy to use, free of clogging when dealing with viscous and high-salt buffer solutions, and with reduced surface interaction with the emitter inner surface. An acquisition of very clean mass spectra of proteins from concentrated solutions of nonvolatile salts such as phosphate-buffered saline is demonstrated.
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Affiliation(s)
- Zhongbao Han
- Faculty of Engineering, University of Yamanashi, 4-3-11, Takeda, Kofu, Yamanashi 400-8511, Japan
| | - Lee Chuin Chen
- Faculty of Engineering, University of Yamanashi, 4-3-11, Takeda, Kofu, Yamanashi 400-8511, Japan
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20
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Gagler DC, Karas B, Kempes CP, Malloy J, Mierzejewski V, Goldman AD, Kim H, Walker SI. Scaling laws in enzyme function reveal a new kind of biochemical universality. Proc Natl Acad Sci U S A 2022; 119:e2106655119. [PMID: 35217602 DOI: 10.1073/pnas.2106655119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2021] [Indexed: 11/21/2022] Open
Abstract
Known examples of life all share the same core biochemistry going back to the last universal common ancestor (LUCA), but whether this feature is universal to other examples, including at the origin of life or alien life, is unknown. We show how a physics-inspired statistical approach identifies universal scaling laws across biochemical reactions that are not defined by common chemical components but instead, as macroscale patterns in the reaction functions used by life. The identified scaling relations can be used to predict statistical features of LUCA, and network analyses reveal some of the functional principles that underlie them. They are, therefore, prime candidates for developing new theory on the “laws of life” that might apply to all possible biochemistries. All life on Earth is unified by its use of a shared set of component chemical compounds and reactions, providing a detailed model for universal biochemistry. However, this notion of universality is specific to known biochemistry and does not allow quantitative predictions about examples not yet observed. Here, we introduce a more generalizable concept of biochemical universality that is more akin to the kind of universality found in physics. Using annotated genomic datasets including an ensemble of 11,955 metagenomes, 1,282 archaea, 11,759 bacteria, and 200 eukaryotic taxa, we show how enzyme functions form universality classes with common scaling behavior in their relative abundances across the datasets. We verify that these scaling laws are not explained by the presence of compounds, reactions, and enzyme functions shared across known examples of life. We demonstrate how these scaling laws can be used as a tool for inferring properties of ancient life by comparing their predictions with a consensus model for the last universal common ancestor (LUCA). We also illustrate how network analyses shed light on the functional principles underlying the observed scaling behaviors. Together, our results establish the existence of a new kind of biochemical universality, independent of the details of life on Earth’s component chemistry, with implications for guiding our search for missing biochemical diversity on Earth or for biochemistries that might deviate from the exact chemical makeup of life as we know it, such as at the origins of life, in alien environments, or in the design of synthetic life.
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21
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Liu R, Li J, Xiao S, Zhang D, He T, Cheng J, Zhu X. Authentic Intelligent Machine for Scaling Driven Discovery: A Case for Chiral Quantum Dots. ACS Nano 2022; 16:1600-1611. [PMID: 34978184 DOI: 10.1021/acsnano.1c10299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The scaling laws have long been used as evidence of science where many fundamental physics laws emerge. As emerging nanomaterials, quantum dots are also sensitive to scaling because of their strong size effect. In this work, we developed the chiral dielectric theory based on the exciton absorption mechanism to explain the increment of the dielectric constant from chirality via its dimensionality. To help researchers discover and develop scaling relevant theories, the Authentic Intelligent Machine (AIM) protocol was developed to generate and interpret experimental data in an analytical and scaling-oriented manner. We show how the AIM protocol interprets spectra such as transient absorption data of chiral quantum dots with theories, where discrepancies concerning the dielectric constant were discovered. Examples for applying the AIM protocol on other spectra, such as absorption spectra and photoluminescence spectra, are also given.
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Affiliation(s)
- Rulin Liu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Shenzhen, Guangdong 518172, China
| | - Jiagen Li
- Shenzhen Institute of Artificial Intelligence and Robotics for Society (AIRS), Shenzhen, Guangdong 518172, China
| | - Shuyu Xiao
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Dongxiang Zhang
- Shenzhen Institute of Artificial Intelligence and Robotics for Society (AIRS), Shenzhen, Guangdong 518172, China
- School of Materials Science and Engineering, Hubei University, Wuhan, Hubei 430062, China
| | - Tingchao He
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Jiaji Cheng
- School of Materials Science and Engineering, Hubei University, Wuhan, Hubei 430062, China
| | - Xi Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Shenzhen, Guangdong 518172, China
- Shenzhen Institute of Artificial Intelligence and Robotics for Society (AIRS), Shenzhen, Guangdong 518172, China
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22
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Perricone V, Santulli C, Rendina F, Langella C. Organismal Design and Biomimetics: A Problem of Scale. Biomimetics (Basel) 2021; 6:biomimetics6040056. [PMID: 34698083 PMCID: PMC8544225 DOI: 10.3390/biomimetics6040056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/16/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022] Open
Abstract
Organisms and their features represent a complex system of solutions that can efficiently inspire the development of original and cutting-edge design applications: the related discipline is known as biomimetics. From the smallest to the largest, every species has developed and adapted different working principles based on their relative dimensional realm. In nature, size changes determine remarkable effects in organismal structures, functions, and evolutionary innovations. Similarly, size and scaling rules need to be considered in the biomimetic transfer of solutions to different dimensions, from nature to artefacts. The observation of principles that occur at very small scales, such as for nano- and microstructures, can often be seen and transferred to a macroscopic scale. However, this transfer is not always possible; numerous biological structures lose their functionality when applied to different scale dimensions. Hence, the evaluation of the effects and changes in scaling biological working principles to the final design dimension is crucial for the success of any biomimetic transfer process. This review intends to provide biologists and designers with an overview regarding scale-related principles in organismal design and their application to technical projects regarding mechanics, optics, electricity, and acoustics.
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Affiliation(s)
- Valentina Perricone
- Department of Engineering, University of Campania Luigi Vanvitelli, Via Roma 29, 81031 Aversa, Italy
- Correspondence: (V.P.); (F.R.)
| | - Carlo Santulli
- School of Science and Technology, Università di Camerino, Via Gentile III da Varano 7, 62032 Camerino, Italy;
| | - Francesco Rendina
- Department of Science and Technology, University of Naples “Parthenope”, URL CoNISMa, Centro Direzionale, Is. C4, 80143 Naples, Italy
- Correspondence: (V.P.); (F.R.)
| | - Carla Langella
- Department of Architecture and Industrial Design, University of Campania Luigi Vanvitelli, Via San Lorenzo, 81031 Aversa, Italy;
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23
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Abstract
Urban scaling analysis, the study of how aggregated urban features vary with the population of an urban area, provides a promising framework for discovering commonalities across cities and uncovering dynamics shared by cities across time and space. Here, we use the urban scaling framework to study an important, but under-explored feature in this community-income inequality. We propose a new method to study the scaling of income distributions by analysing total income scaling in population percentiles. We show that income in the least wealthy decile (10%) scales close to linearly with city population, while income in the most wealthy decile scale with a significantly superlinear exponent. In contrast to the superlinear scaling of total income with city population, this decile scaling illustrates that the benefits of larger cities are increasingly unequally distributed. For the poorest income deciles, cities have no positive effect over the null expectation of a linear increase. We repeat our analysis after adjusting income by housing cost, and find similar results. We then further analyse the shapes of income distributions. First, we find that mean, variance, skewness and kurtosis of income distributions all increase with city size. Second, the Kullback-Leibler divergence between a city's income distribution and that of the largest city decreases with city population, suggesting the overall shape of income distribution shifts with city population. As most urban scaling theories consider densifying interactions within cities as the fundamental process leading to the superlinear increase of many features, our results suggest this effect is only seen in the upper deciles of the cities. Our finding encourages future work to consider heterogeneous models of interactions to form a more coherent understanding of urban scaling.
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Affiliation(s)
- Elisa Heinrich Mora
- Minerva Schools at KGI, San Francisco, CA 94103, USA.,Santa Fe institute, Santa Fe, NM 87501, USA
| | - Cate Heine
- Santa Fe institute, Santa Fe, NM 87501, USA.,Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jacob J Jackson
- Santa Fe institute, Santa Fe, NM 87501, USA.,Brown University, Providence, RI 02912, USA
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24
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Fahimi P, Matta CF. On the power per mitochondrion and the number of associated active ATP synthases. Phys Biol 2021; 18. [PMID: 33853054 DOI: 10.1088/1478-3975/abf7d9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/14/2021] [Indexed: 11/12/2022]
Abstract
Recent experiments and thermodynamic arguments suggest that mitochondrial temperatures are higher than those of the cytoplasm. A "hot mitochondrion" calls for a closer examination of the energy balance that endows it with these claimed elevated temperatures. As a first step in this effort, we present here a semi-quantitative bookkeeping whereby, in one stroke, a formula is proposed that yields the rate of heat production in a typical mitochondrion and a formula for estimating the number of "active" ATP synthase molecules per mitochondrion. The number of active ATP synthase molecules is the equivalent number of ATP synthases operating at 100% capacity to maintain the rate of mitochondrial heat generation. Scaling laws are shown to determine the number of active ATP synthase molecules in a mitochondrion and mitochondrial rate of heat production, whereby both appear to scale with cell volume. Four heterotrophic protozoan cell types are considered in this study. The studied cells, selected to cover a wide range of sizes (volumes) fromca.100μm3to 1 millionμm3, are estimated to exhibit a power per mitochondrion ranging fromca.1 pW to 0.03 pW. In these cells, the corresponding number of active ATP synthases per mitochondrion ranges from 5000 to just about a hundred. The absolute total number of ATP synthase molecules per mitochondrion, regardless of their activity status, can be up to two orders of magnitudes higher.
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Affiliation(s)
- Peyman Fahimi
- Department of Chemistry and Physics, Mount Saint Vincent University, Halifax, Nova Scotia, B3M2J6, Canada.,Département de Chimie, Université Laval, Québec, Québec, G1V0A6, Canada
| | - Chérif F Matta
- Department of Chemistry and Physics, Mount Saint Vincent University, Halifax, Nova Scotia, B3M2J6, Canada.,Département de Chimie, Université Laval, Québec, Québec, G1V0A6, Canada.,Department of Chemistry, Saint Mary's University, Halifax, Nova Scotia, B3H3C3, Canada.,Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, B3H4J3, Canada
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25
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Schiavone G, Vachicouras N, Vyza Y, Lacour SP. Dimensional scaling of thin-film stimulation electrode systems in translational research. J Neural Eng 2021; 18. [PMID: 33831857 DOI: 10.1088/1741-2552/abf607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/08/2021] [Indexed: 12/20/2022]
Abstract
Objective.Electrical stimulation of biological tissue is an established technique in research and clinical practice that uses implanted electrodes to deliver electrical pulses for a variety of therapies. Significant research currently explores new electrode system technologies and stimulation protocols in preclinical models, aiming at both improving the electrode performance and confirming therapeutic efficacy. Assessing the scalability of newly proposed electrode technology and their use for tissue stimulation remains, however, an open question.Approach.We propose a simplified electrical model that formalizes the dimensional scaling of stimulation electrode systems. We use established equations describing the electrode impedance, and apply them to the case of stimulation electrodes driven by a voltage-capped pulse generator.Main results.We find a hard, intrinsic upward scalability limit to the electrode radius that largely depends on the conductor technology. We finally provide a simple analytical formula predicting the maximum size of a stimulation electrode as a function of the stimulation parameters and conductor resistance.Significance.Our results highlight the importance of careful geometrical and electrical designs of electrode systems based on novel thin-film technologies and that become particularly relevant for their translational implementation with electrode geometries approaching clinical human size electrodes and interfacing with voltage-capped neurostimulation systems.
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Affiliation(s)
- Giuseppe Schiavone
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne, 1202 Geneva, Switzerland
| | - Nicolas Vachicouras
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne, 1202 Geneva, Switzerland
| | - Yashwanth Vyza
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne, 1202 Geneva, Switzerland
| | - Stéphanie P Lacour
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne, 1202 Geneva, Switzerland
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26
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Abstract
The fundamental attributes of charged hydrogels containing predominantly water and controllable amounts of low molar mass electrolytes are of tremendous significance in biological context and applications in healthcare. However, a rigorous theoretical formulation of gel behavior continues to be a challenge due to the presence of multiple length and time scales in the system which operate simultaneously. Furthermore, chain connectivity, the electrostatic interaction, and the hydrodynamic interaction all lead to long-range interactions. In spite of these complications, considerable progress has been achieved over the past several decades in generating theories of variable complexity. The present review presents an analytically tractable theory by accounting for correlations emerging from topological, electrostatic, and hydrodynamic interactions. Closed-form formulas are derived for charged hydrogels to describe their swelling equilibrium, elastic moduli, and the relationship between microscopic properties such as gel diffusion and macroscopic properties such as elasticity. In addition, electrostatic coupling between charged moieties and their ion clouds, which significantly modifies the elastic diffusion coefficient of gels, and various scaling laws are presented. The theoretical formulas summarized here are useful to adequately capture the essentials of the physics of charged gels and to design new hydrogels with specified elastic and dynamical properties.
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27
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Abstract
To clarify whether a surface can be rough with faceted macrosteps that maintain their shape on the surface, crystal surface roughness is studied by a Monte Carlo method for a nucleation-limited crystal-growth process. As a surface model, the restricted solid-on-solid (RSOS) model with point-contact-type step-step attraction (p-RSOS model) is adopted. At equilibrium and at sufficiently low temperatures, the vicinal surface of the p-RSOS model consists of faceted macrosteps with (111) side surfaces and smooth terraces with (001) surfaces (the step-faceting zone). We found that a surface with faceted macrosteps has an approximately self-affine-rough structure on a 'faceted-rough surface'; the surface width is strongly divergent at the step-disassembling point, which is a characteristic driving force for crystal growth. A 'faceted-rough surface' is realized in the region between the step-disassembling point and a crossover point where the single nucleation growth changes to poly-nucleation growth.
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Affiliation(s)
- Noriko Akutsu
- Faculty of Engineering, Osaka Electro-Communication University, Hatsu-cho, Neyagawa, Osaka, 572-8530, Japan.
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28
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Abstract
Generic scaling laws, such as Kolmogorov's 5/3 law, are milestone achievements of turbulence research in classical fluids. For quantum fluids such as atomic Bose-Einstein condensates, superfluid helium, and superfluid neutron stars, turbulence can also exist in the presence of a chaotic tangle of evolving quantized vortex lines. However, due to the lack of suitable experimental tools to directly probe the vortex-tangle motion, so far little is known about possible scaling laws that characterize the velocity correlations and trajectory statistics of the vortices in quantum-fluid turbulence, i.e., quantum turbulence (QT). Acquiring such knowledge could greatly benefit the development of advanced statistical models of QT. Here we report an experiment where a tangle of vortices in superfluid 4He are decorated with solidified deuterium tracer particles. Under experimental conditions where these tracers follow the motion of the vortices, we observed an apparent superdiffusion of the vortices. Our analysis shows that this superdiffusion is not due to Lévy flights, i.e., long-distance hops that are known to be responsible for superdiffusion of random walkers. Instead, a previously unknown power-law scaling of the vortex-velocity temporal correlation is uncovered as the cause. This finding may motivate future research on hidden scaling laws in QT.
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Affiliation(s)
- Yuan Tang
- The Cryogenics Laboratory, National High Magnetic Field Laboratory, Tallahassee, FL 32310
- Mechanical Engineering Department, Florida State University, Tallahassee, FL 32310
| | - Shiran Bao
- The Cryogenics Laboratory, National High Magnetic Field Laboratory, Tallahassee, FL 32310
- Mechanical Engineering Department, Florida State University, Tallahassee, FL 32310
| | - Wei Guo
- The Cryogenics Laboratory, National High Magnetic Field Laboratory, Tallahassee, FL 32310;
- Mechanical Engineering Department, Florida State University, Tallahassee, FL 32310
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29
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Abstract
In this study, asymptotic analysis of the frequency-domain formulation to compute the tonal noise of the small rotors in the now ubiquitously multi-rotor powered drones is conducted. Simple scaling laws are proposed to evaluate the impacts of the influential parameters such as blade number, flow speed, rotation speed, unsteady motion, thrust and observer angle on the tonal noise. The rate of noise increment with thrust (or rotational speed) is determined by orders of blade passing frequency harmonics and the unsteady motion. The axial mean flow influence can be approximated by quadratic functions. At given thrust, the sound decreases rapidly with the radius and blade number as the surface pressure becomes less intensive. The higher tonal harmonics are significantly increased if unsteady motions, although of small-amplitude, are existed, as indicated by the defined sensitivity function, emphasizing that the unsteady motions should be avoided for quiet rotor designs. The scaling laws are examined by comparing with the full computations of the rotor noise using the frequency-domain method, the implementation of which has been validated by comparing with experiments. Good data collapse is obtained when the proposed scaling laws, which highlights the dominant influence of the design parameters, are incorporated.
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Affiliation(s)
- Siyang Zhong
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
- HKUST Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Peng Zhou
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Ryu Fattah
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Xin Zhang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
- HKUST-Shenzhen Research Institute, Shenzhen, 518057, China
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Liu M, Apriceno A, Sipin M, Scarpa E, Rodriguez-Arco L, Poma A, Marchello G, Battaglia G, Angioletti-Uberti S. Combinatorial entropy behaviour leads to range selective binding in ligand-receptor interactions. Nat Commun 2020; 11:4836. [PMID: 32973157 PMCID: PMC7515919 DOI: 10.1038/s41467-020-18603-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 08/28/2020] [Indexed: 12/18/2022] Open
Abstract
From viruses to nanoparticles, constructs functionalized with multiple ligands display peculiar binding properties that only arise from multivalent effects. Using statistical mechanical modelling, we describe here how multivalency can be exploited to achieve what we dub range selectivity, that is, binding only to targets bearing a number of receptors within a specified range. We use our model to characterise the region in parameter space where one can expect range selective targeting to occur, and provide experimental support for this phenomenon. Overall, range selectivity represents a potential path to increase the targeting selectivity of multivalent constructs.
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Affiliation(s)
- Meng Liu
- Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, People's Republic of China
- Institute of Physics, Chinese Academy of Science, Beijing, People's Republic of China
| | - Azzurra Apriceno
- Department of Chemistry, University College London, London, UK
- Institute for the Physics of Living Systems, University College London, London, UK
| | - Miguel Sipin
- Department of Chemistry, University College London, London, UK
- Institute for the Physics of Living Systems, University College London, London, UK
| | - Edoardo Scarpa
- Department of Chemistry, University College London, London, UK
- Institute for the Physics of Living Systems, University College London, London, UK
| | - Laura Rodriguez-Arco
- Department of Chemistry, University College London, London, UK
- Institute for the Physics of Living Systems, University College London, London, UK
| | - Alessandro Poma
- Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, London, UK
| | - Gabriele Marchello
- Institute for the Physics of Living Systems, University College London, London, UK
- Physical Chemistry Chemical Physics Division, Department of Chemistry, University College London, London, UK
- The UCL EPSRC/JEOL Centre for Liquid Phase Electron Microscopy, London, UK
| | - Giuseppe Battaglia
- Department of Chemistry, University College London, London, UK.
- Institute for the Physics of Living Systems, University College London, London, UK.
- The UCL EPSRC/JEOL Centre for Liquid Phase Electron Microscopy, London, UK.
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain.
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain.
| | - Stefano Angioletti-Uberti
- Institute of Physics, Chinese Academy of Science, Beijing, People's Republic of China.
- Department of Materials, Imperial College London, London, UK.
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31
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Xue C, Liu Z, Goldenfeld N. Scale-invariant topology and bursty branching of evolutionary trees emerge from niche construction. Proc Natl Acad Sci U S A 2020; 117:7879-87. [PMID: 32209672 DOI: 10.1073/pnas.1915088117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Phylogenetic trees describe both the evolutionary process and community diversity. Recent work has established that they exhibit scale-invariant topology, which quantifies the fact that their branching lies in between the two extreme cases of balanced binary trees and maximally unbalanced ones. In addition, the backbones of phylogenetic trees exhibit bursts of diversification on all timescales. Here, we present a simple, coarse-grained statistical model of niche construction coupled to speciation. Finite-size scaling analysis of the dynamics shows that the resultant phylogenetic tree topology is scale-invariant due to a singularity arising from large niche construction fluctuations that follow extinction events. The same model recapitulates the bursty pattern of diversification in time. These results show how dynamical scaling laws of phylogenetic trees on long timescales can reflect the indelible imprint of the interplay between ecological and evolutionary processes.
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Ayancik F, Fish FE, Moored KW. Three-dimensional scaling laws of cetacean propulsion characterize the hydrodynamic interplay of flukes' shape and kinematics. J R Soc Interface 2020; 17:20190655. [PMID: 32093541 DOI: 10.1098/rsif.2019.0655] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cetaceans convert dorsoventral body oscillations into forward velocity with a complex interplay between their morphological and kinematic features and the fluid environment. However, it is unknown to what extent morpho-kinematic features of cetaceans are intertwined to maximize their efficiency. By interchanging the shape and kinematic variables of five cetacean species, the interplay of their flukes morpho-kinematic features is examined by characterizing their thrust, power and propulsive efficiency. It is determined that the shape and kinematics of the flukes have considerable influence on force production and power consumption. Three-dimensional heaving and pitching scaling laws are developed by considering both added mass and circulatory-based forces, which are shown to closely model the numerical data. Using the scaling relations as a guide, it is determined that the added mass forces are important in predicting the trend between the efficiency and aspect ratio, however, the thrust and power are driven predominately by the circulatory forces. The scaling laws also reveal that there is an optimal dimensionless heave-to-pitch ratio h* that maximizes the efficiency. Moreover, the optimal h* varies with the aspect ratio, the amplitude-to-chord ratio and the Lighthill number. This indicates that the shape and kinematics of propulsors are intertwined, that is, there are specific kinematics that are tailored to the shape of a propulsor in order to maximize its propulsive efficiency.
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Affiliation(s)
- Fatma Ayancik
- Department of Mechanical Engineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Frank E Fish
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - Keith W Moored
- Department of Mechanical Engineering, Lehigh University, Bethlehem, PA 18015, USA
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33
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Schwarz JCV, van Lier MGJTB, van den Wijngaard JPHM, Siebes M, VanBavel E. Topologic and Hemodynamic Characteristics of the Human Coronary Arterial Circulation. Front Physiol 2020; 10:1611. [PMID: 32038291 PMCID: PMC6989553 DOI: 10.3389/fphys.2019.01611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/23/2019] [Indexed: 11/26/2022] Open
Abstract
Background Many processes contributing to the functional and structural regulation of the coronary circulation have been identified. A proper understanding of the complex interplay of these processes requires a quantitative systems approach that includes the complexity of the coronary network. The purpose of this study was to provide a detailed quantification of the branching characteristics and local hemodynamics of the human coronary circulation. Methods The coronary arteries of a human heart were filled post-mortem with fluorescent replica material. The frozen heart was alternately cut and block-face imaged using a high-resolution imaging cryomicrotome. From the resulting 3D reconstruction of the left coronary circulation, topological (node and loop characteristics), topographic (diameters and length of segments), and geometric (position) properties were analyzed, along with predictions of local hemodynamics (pressure and flow). Results The reconstructed left coronary tree consisted of 202,184 segments with diameters ranging from 30 μm to 4 mm. Most segments were between 100 μm and 1 mm long. The median segment length was similar for diameters ranging between 75 and 200 μm. 91% of the nodes were bifurcations. These bifurcations were more symmetric and less variable in smaller vessels. Most of the pressure drop occurred in vessels between 200 μm and 1 mm in diameter. Downstream conductance variability affected neither local pressure nor median local flow and added limited extra variation of local flow. The left coronary circulation perfused 358 cm3 of myocardium. Median perfused volume at a truncation level of 100 to 200 μm was 20 mm3 with a median perfusion of 5.6 ml/min/g and a high local heterogeneity. Conclusion This study provides the branching characteristics and hemodynamic analysis of the left coronary arterial circulation of a human heart. The resulting model can be deployed for further hemodynamic studies at the whole organ and local level.
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Affiliation(s)
- Janina C V Schwarz
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Monique G J T B van Lier
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | | | - Maria Siebes
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Charmet J, Rodrigues R, Yildirim E, Challa PK, Roberts B, Dallmann R, Whulanza Y. Low-Cost Microfabrication Tool Box. Micromachines (Basel) 2020; 11:mi11020135. [PMID: 31991826 PMCID: PMC7074766 DOI: 10.3390/mi11020135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 01/27/2023]
Abstract
Microsystems are key enabling technologies, with applications found in almost every industrial field, including in vitro diagnostic, energy harvesting, automotive, telecommunication, drug screening, etc. Microsystems, such as microsensors and actuators, are typically made up of components below 1000 microns in size that can be manufactured at low unit cost through mass-production. Yet, their development for commercial or educational purposes has typically been limited to specialized laboratories in upper-income countries due to the initial investment costs associated with the microfabrication equipment and processes. However, recent technological advances have enabled the development of low-cost microfabrication tools. In this paper, we describe a range of low-cost approaches and equipment (below £1000), developed or adapted and implemented in our laboratories. We describe processes including photolithography, micromilling, 3D printing, xurography and screen-printing used for the microfabrication of structural and functional materials. The processes that can be used to shape a range of materials with sub-millimetre feature sizes are demonstrated here in the context of lab-on-chips, but they can be adapted for other applications. We anticipate that this paper, which will enable researchers to build a low-cost microfabrication toolbox in a wide range of settings, will spark a new interest in microsystems.
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Affiliation(s)
- Jérôme Charmet
- Warwick Manufacturing Group (WMG), University of Warwick, Coventry CV4 7AL, UK;
- Correspondence: (J.C.); (Y.W.); Tel.: +44-24-765-73566 (J.C.); +62-21-7270032 (Y.W.)
| | - Rui Rodrigues
- Warwick Manufacturing Group (WMG), University of Warwick, Coventry CV4 7AL, UK;
| | - Ender Yildirim
- Mechanical Engineering Department, Middle East Technical University, 06800 Ankara, Turkey;
| | - Pavan Kumar Challa
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK;
| | - Benjamin Roberts
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK; (B.R.); (R.D.)
- MRC Doctoral Training Programme in Interdisciplinary Biomedical Research, University of Warwick, Coventry CV4 7AL, UK
| | - Robert Dallmann
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK; (B.R.); (R.D.)
| | - Yudan Whulanza
- Department of Mechanical Engineering, Universitas Indonesia, Depok 16424, Indonesia
- Correspondence: (J.C.); (Y.W.); Tel.: +44-24-765-73566 (J.C.); +62-21-7270032 (Y.W.)
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35
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Sudre G, Siband E, Gallas B, Cousin F, Hourdet D, Tran Y. Responsive Adsorption of N-Isopropylacrylamide Based Copolymers on Polymer Brushes. Polymers (Basel) 2020; 12:polym12010153. [PMID: 31936092 PMCID: PMC7022643 DOI: 10.3390/polym12010153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 01/12/2023] Open
Abstract
We investigate the adsorption of pH- or temperature-responsive polymer systems by ellipsometry and neutron reflectivity. To this end, temperature-responsive poly (N-isopropylacrylamide) (PNIPAM) brushes and pH-responsive poly (acrylic acid) (PAA) brushes have been prepared using the "grafting onto" method to investigate the adsorption process of polymers and its reversibility under controlled environment. To that purpose, macromolecular brushes were designed with various chain lengths and a wide range of grafting density. Below the transition temperature (LCST), the characterization of PNIPAM brushes by neutron reflectivity shows that the swelling behavior of brushes is in good agreement with the scaling models before they collapse above the LCST. The reversible adsorption on PNIPAM brushes was carried out with linear copolymers of N-isopropylacrylamide and acrylic acid, P(NIPAM-co-AA). While these copolymers remain fully soluble in water over the whole range of temperature investigated, a quantitative adsorption driven by solvophobic interactions was shown to proceed only above the LCST of the brush and to be totally reversible upon cooling. Similarly, the pH-responsive adsorption driven by electrostatic interactions on PAA brushes was studied with copolymers of NIPAM and N,N-dimethylaminopropylmethacrylamide, P(NIPAM-co-MADAP). In this case, the adsorption of weak polycations was shown to increase with the ionization of the PAA brush with interactions mainly located in the upper part of the brush at pH 7 and more deeply adsorbed within the brush at pH 9.
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Affiliation(s)
- Guillaume Sudre
- Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223, 69100 Villeurbanne, France
- Correspondence: (G.S.); (Y.T.)
| | - Elodie Siband
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France; (E.S.); (D.H.)
| | - Bruno Gallas
- Sorbonne Université, CNRS-UMR 7588, Institut des NanoSciences de Paris, INSP, 4 place Jussieu, F-75005 Paris, France;
| | - Fabrice Cousin
- Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS, Saclay, 91191 Gif-sur-Yvette CEDEX, France;
| | - Dominique Hourdet
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France; (E.S.); (D.H.)
| | - Yvette Tran
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France; (E.S.); (D.H.)
- Correspondence: (G.S.); (Y.T.)
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van Langevelde F, Comor V, de Bie S, Prins HHT, Thakur MP. Disturbance regulates the density-body-mass relationship of soil fauna. Ecol Appl 2020; 30:e02019. [PMID: 31600842 PMCID: PMC7003476 DOI: 10.1002/eap.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/03/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Theory on the density-body-mass (DBM) relationship predicts that the density of animal species decreases by the power of -0.75 per unit increase in their body mass, or by the power of -1 when taxa across trophic levels are studied. This relationship is, however, largely debated, as the slope often deviates from the theoretical predictions. Here, we tested the ability of the DBM relationship to reflect changes in the structure of communities subjected to an anthropogenic disturbance. The slope would become less steep if smaller animals were more impacted by the disturbance than the larger ones, whereas the slope would become steeper if larger animals were more affected than the smaller ones. We tested the changes in the DBM relationship by sampling soil fauna, i.e., nematodes, Collembola, and larger arthropods, from a semiarid grassland before and after spraying diesel fuel as disturbance. We applied three different treatments: a control, a light disturbance, and an intense disturbance. We found that the slopes of the DBM relationships before the disturbance were around -1 as predicted by theory. The slope became more positive (i.e., less steep) just after the disturbance, especially after the intense disturbance as smaller fauna suffered the most and early colonizers had larger body mass. Interestingly, we observed that the slopes converged back to -1 by 2 months post-disturbance. Our findings show that the response of soil fauna communities to anthropogenic disturbances could explain the large variation in observed slopes of the DBM relationships. We experimentally demonstrate that an animal community, when disturbed, shows a temporal pattern of DBM relationships ranging from deviations from the predicted slope to convergence to the predicted slope with time. We recommend that deviations in the DBM relationships after disturbances can provide insights in the trajectory of community recovery, and hence could be used for biomonitoring.
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Affiliation(s)
- Frank van Langevelde
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
- School of Life SciencesUniversity of KwaZulu‐NatalWestville CampusDurban4000South Africa
| | - Vincent Comor
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
| | - Steven de Bie
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
| | - Herbert H. T. Prins
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
| | - Madhav P. Thakur
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)Droevendaalsesteeg 10Wageningen6708 PBThe Netherlands
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Zhu F, Emile-Geay J, McKay NP, Hakim GJ, Khider D, Ault TR, Steig EJ, Dee S, Kirchner JW. Climate models can correctly simulate the continuum of global-average temperature variability. Proc Natl Acad Sci U S A 2019; 116:8728-33. [PMID: 30988176 DOI: 10.1073/pnas.1809959116] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Climate records exhibit scaling behavior with large exponents, resulting in larger fluctuations at longer timescales. It is unclear whether climate models are capable of simulating these fluctuations, which draws into question their ability to simulate such variability in the coming decades and centuries. Using the latest simulations and data syntheses, we find agreement for spectra derived from observations and models on timescales ranging from interannual to multimillennial. Our results confirm the existence of a scaling break between orbital and annual peaks, occurring around millennial periodicities. That both simple and comprehensive ocean-atmosphere models can reproduce these features suggests that long-range persistence is a consequence of the oceanic integration of both gradual and abrupt climate forcings. This result implies that Holocene low-frequency variability is partly a consequence of the climate system's integrated memory of orbital forcing. We conclude that climate models appear to contain the essential physics to correctly simulate the spectral continuum of global-mean temperature; however, regional discrepancies remain unresolved. A critical element of successfully simulating suborbital climate variability involves, we hypothesize, initial conditions of the deep ocean state that are consistent with observations of the recent past.
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Abstract
The concept of resilience can be realized in natural and engineering systems, representing the ability of a system to adapt and recover from various disturbances. Although resilience is a critical property needed for understanding and managing the risks and collapses of transportation systems, an accepted and useful definition of resilience for urban traffic as well as its statistical property under perturbations are still missing. Here, we define city traffic resilience based on the spatiotemporal clusters of congestion in real traffic and find that the resilience follows a scale-free distribution in 2D city road networks and 1D highways with different exponents but similar exponents on different days and in different cities. The traffic resilience is also revealed to have a scaling relation between the cluster size of the spatiotemporal jam and its recovery duration independent of microscopic details. Our findings of universal traffic resilience can provide an indication toward better understanding and designing of these complex engineering systems under internal and external disturbances.
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Wu W, Zhao H, Tan Q, Gao P. An Urban Scaling Estimation Method in a Heterogeneity Variance Perspective. Entropy (Basel) 2019; 21:e21040337. [PMID: 33267051 PMCID: PMC7514821 DOI: 10.3390/e21040337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/14/2019] [Accepted: 03/25/2019] [Indexed: 11/16/2022]
Abstract
Urban scaling laws describe powerful universalities of the scaling relationships between urban attributes and the city size across different countries and times. There are still challenges in precise statistical estimation of the scaling exponent; the properties of variance require further study. In this paper, a statistical regression method based on the maximum likelihood estimation considering the lower bound constraints and the heterogeneous variance of error structure, termed as CHVR, is proposed for urban scaling estimation. In the CHVR method, the heterogeneous properties of variance are explored and modeled in the form of a power-of-the-mean variance model. The maximum likelihood fitting method is supplemented to satisfy the lower bound constraints in empirical data. The CHVR method has been applied to estimating the scaling exponents of six urban attributes covering three scaling regimes in China and compared with two traditional methods. Method evaluations based on three different criteria validate that compared with both classical methods, the CHVR method is more effective and robust. Moreover, a statistical test and long-term variations of the parameter in the variance function demonstrate that the proposed heterogeneous variance function can not only describe the heterogeneity in empirical data adequately but also provide more meaningful urban information. Therefore, the CHVR method shows great potential to provide a valuable tool for effective urban scaling studies across the world and be applied to scaling law estimation in other complex systems in the future.
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Affiliation(s)
- Wenjia Wu
- Institute of Geomatics, Department of Civil Engineering, Tsinghua University, Beijing 100084, China
- 3S Center, Tsinghua University, Beijing 100084, China
- National Engineering Laboratory for Green and Safe Construction Technology in Urban Rail Transit, Tsinghua University, Beijing 100084, China
| | - Hongrui Zhao
- Institute of Geomatics, Department of Civil Engineering, Tsinghua University, Beijing 100084, China
- 3S Center, Tsinghua University, Beijing 100084, China
- National Engineering Laboratory for Green and Safe Construction Technology in Urban Rail Transit, Tsinghua University, Beijing 100084, China
- Correspondence: ; Tel.: +86-010-62782682
| | - Qifan Tan
- Institute of Geomatics, Department of Civil Engineering, Tsinghua University, Beijing 100084, China
- 3S Center, Tsinghua University, Beijing 100084, China
- National Engineering Laboratory for Green and Safe Construction Technology in Urban Rail Transit, Tsinghua University, Beijing 100084, China
| | - Peichao Gao
- Faculty of Geographical Science, Beijing Normal University, Beijing100084, China
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Martínez-Martínez CT, Méndez-Bermúdez JA. Information Entropy of Tight-Binding Random Networks with Losses and Gain: Scaling and Universality. Entropy (Basel) 2019; 21:e21010086. [PMID: 33266802 PMCID: PMC7514196 DOI: 10.3390/e21010086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/01/2019] [Accepted: 01/15/2019] [Indexed: 11/16/2022]
Abstract
We study the localization properties of the eigenvectors, characterized by their information entropy, of tight-binding random networks with balanced losses and gain. The random network model, which is based on Erdős–Rényi (ER) graphs, is defined by three parameters: the network size N, the network connectivity α, and the losses-and-gain strength γ. Here, N and α are the standard parameters of ER graphs, while we introduce losses and gain by including complex self-loops on all vertices with the imaginary amplitude iγ with random balanced signs, thus breaking the Hermiticity of the corresponding adjacency matrices and inducing complex spectra. By the use of extensive numerical simulations, we define a scaling parameter ξ≡ξ(N,α,γ) that fixes the localization properties of the eigenvectors of our random network model; such that, when ξ<0.1 (10<ξ), the eigenvectors are localized (extended), while the localization-to-delocalization transition occurs for 0.1<ξ<10. Moreover, to extend the applicability of our findings, we demonstrate that for fixed ξ, the spectral properties (characterized by the position of the eigenvalues on the complex plane) of our network model are also universal; i.e., they do not depend on the specific values of the network parameters.
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Zhao S, Liu S, Xu C, Yuan W, Sun Y, Yan W, Zhao M, Henebry GM, Fang J. Contemporary evolution and scaling of 32 major cities in China. Ecol Appl 2018; 28:1655-1668. [PMID: 29869352 DOI: 10.1002/eap.1760] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 04/05/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
Most of the planet's population currently lives in urban areas, and urban land expansion is one of the most dramatic forms of land conversion. Understanding how cities evolve temporally, spatially, and organizationally in a rapidly urbanizing world is critical for sustainable development. However, few studies have examined the coevolution of urban attributes in time and space simultaneously and the adequacy of power law scaling across cities and through time, particularly in countries that have experienced abrupt, widespread, political and economic changes. Here, we show the temporal coevolution of multiple physical, demographic, socioeconomic, and environmental attributes in individual cities, and the cross-city scaling of urban attributes at six time points (i.e., 1978, 1990, 1995, 2000, 2005, and 2010) in 32 major Chinese cities. We found that power law scaling could adequately characterize both the cross-city scaling of urban attributes across cities and the longitudinal scaling describing the temporal coevolution of urban attributes within individual cities. The cross-city scaling properties demonstrated substantial changes over time signifying evolved social and economic forces. A key finding was that the cross-city linear or superlinear scaling of urban area with population contradicts the theoretical sublinear power law scaling proposed between infrastructure and population. Furthermore, the cross-city scaling between area and population transitioned from linear to superlinear over time, and the superlinear scaling in recent times suggests decreased infrastructure efficiency. Our results demonstrate a diseconomy of scale in urban areal expansion that indicates a significant waste of land resources in the urbanization process. Future planning efforts should focus on policies that increase urban land use efficiency before continuing expansion.
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Affiliation(s)
- Shuqing Zhao
- Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Shuguang Liu
- National Engineering Laboratory of Forest Ecology and Applied Technology for Southern China, College of Biological Science and Technology, Central South University of Forest and Technology, Changsha, 410004, China
| | - Chunxue Xu
- Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Wenping Yuan
- Key Laboratory of Urban Climate and Ecodynamics, Zhuhai Joint Innovative Center for Climate-Environment-Ecosystem, Beijing Normal University, Zhuhai, 519087, China
| | - Yan Sun
- Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Wende Yan
- National Engineering Laboratory of Forest Ecology and Applied Technology for Southern China, College of Biological Science and Technology, Central South University of Forest and Technology, Changsha, 410004, China
| | - Meifang Zhao
- National Engineering Laboratory of Forest Ecology and Applied Technology for Southern China, College of Biological Science and Technology, Central South University of Forest and Technology, Changsha, 410004, China
| | - Geoffrey M Henebry
- Geospatial Sciences Center of Excellence (GSCE), South Dakota State University, Brookings, South Dakota, 57007, USA
| | - Jingyun Fang
- Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
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Heisser RH, Patil VP, Stoop N, Villermaux E, Dunkel J. Controlling fracture cascades through twisting and quenching. Proc Natl Acad Sci U S A 2018; 115:8665-70. [PMID: 30104353 DOI: 10.1073/pnas.1802831115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fracture fundamentally limits the structural stability of macroscopic and microscopic matter, from beams and bones to microtubules and nanotubes. Despite substantial recent experimental and theoretical progress, fracture control continues to present profound practical and theoretical challenges. While bending-induced fracture of elongated rod-like objects has been intensely studied, the effects of twist and quench dynamics have yet to be explored systematically. Here, we show how twist and quench protocols may be used to control such fracture processes, by revisiting Feynman's observation that dry spaghetti typically breaks into three or more pieces when exposed to large pure bending stresses. Combining theory and experiment, we demonstrate controlled binary fracture of brittle elastic rods for two distinct protocols based on twisting and nonadiabatic quenching. Our experimental data for twist-controlled fracture agree quantitatively with a theoretically predicted phase diagram, and we establish asymptotic scaling relations for quenched fracture. Due to their general character, these results are expected to apply to torsional and kinetic fracture processes in a wide range of systems.
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Bokka V, Dey A, Sen S. Period-amplitude co-variation in biomolecular oscillators. IET Syst Biol 2018; 12:190-198. [PMID: 33451181 PMCID: PMC8687215 DOI: 10.1049/iet-syb.2018.0015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/02/2018] [Accepted: 04/08/2018] [Indexed: 11/19/2022] Open
Abstract
The period and amplitude of biomolecular oscillators are functionally important properties in multiple contexts. For a biomolecular oscillator, the overall constraints in how tuning of amplitude affects period, and vice versa, are generally unclear. Here, the authors investigate this co-variation of the period and amplitude in mathematical models of biomolecular oscillators using both simulations and analytical approximations. The authors computed the amplitude-period co-variation of 11 benchmark biomolecular oscillators as their parameters were individually varied around a nominal value, classifying the various co-variation patterns such as a simultaneous increase/decrease in period and amplitude. Next, the authors repeated the classification using a power norm-based amplitude metric, to account for the amplitudes of the many biomolecular species that may be part of the oscillations, finding largely similar trends. Finally, the authors calculate 'scaling laws' of period-amplitude co-variation for a subset of these benchmark oscillators finding that as the approximated period increases, the upper bound of the amplitude increases, or reaches a constant value. Based on these results, the authors discuss the effect of different parameters on the type of period-amplitude co-variation as well as the difficulty in achieving an oscillation with large amplitude and small period.
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Affiliation(s)
- Venkat Bokka
- Department of Electrical EngineeringIIT DelhiHauz KhasNew DelhiIndia
| | - Abhishek Dey
- Department of Electrical EngineeringIIT DelhiHauz KhasNew DelhiIndia
| | - Shaunak Sen
- Department of Electrical EngineeringIIT DelhiHauz KhasNew DelhiIndia
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44
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Razavi MS, Shirani E, Kassab GS. Scaling Laws of Flow Rate, Vessel Blood Volume, Lengths, and Transit Times With Number of Capillaries. Front Physiol 2018; 9:581. [PMID: 29875687 PMCID: PMC5974547 DOI: 10.3389/fphys.2018.00581] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 05/01/2018] [Indexed: 11/13/2022] Open
Abstract
The structure-function relation is one of the oldest hypotheses in biology and medicine; i.e., form serves function and function influences form. Here, we derive and validate form-function relations for volume, length, flow, and mean transit time in vascular trees and capillary numbers of various organs and species. We define a vessel segment as a "stem" and the vascular tree supplied by the stem as a "crown." We demonstrate form-function relations between the number of capillaries in a vascular network and the crown volume, crown length, and blood flow that perfuses the network. The scaling laws predict an exponential relationship between crown volume and the number of capillaries with the power, λ, of 4/3 < λ < 3/2. It is also shown that blood flow rate and vessel lengths are proportional to the number of capillaries in the entire stem-crown systems. The integration of the scaling laws then results in a relation between transit time and crown length and volume. The scaling laws are both intra-specific (i.e., within vasculatures of various organs, including heart, lung, mesentery, skeletal muscle and eye) and inter-specific (i.e., across various species, including rats, cats, rabbits, pigs, hamsters, and humans). This study is fundamental to understanding the physiological structure and function of vascular trees to transport blood, with significant implications for organ health and disease.
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Affiliation(s)
- Mohammad S Razavi
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, United States.,The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, United States
| | - Ebrahim Shirani
- Department of Engineering, Foolad Institute of Technology, Isfahan, Iran
| | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, CA, United States
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Méndez-Bermúdez JA, Aguilar-Sánchez R. Information-Length Scaling in a Generalized One-Dimensional Lloyd's Model. Entropy (Basel) 2018; 20:e20040300. [PMID: 33265391 PMCID: PMC7512818 DOI: 10.3390/e20040300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/29/2018] [Accepted: 04/08/2018] [Indexed: 01/28/2023]
Abstract
We perform a detailed numerical study of the localization properties of the eigenfunctions of one-dimensional (1D) tight-binding wires with on-site disorder characterized by long-tailed distributions: For large ϵ , P ( ϵ ) ∼ 1 / ϵ 1 + α with α ∈ ( 0 , 2 ] ; where ϵ are the on-site random energies. Our model serves as a generalization of 1D Lloyd's model, which corresponds to α = 1 . In particular, we demonstrate that the information length β of the eigenfunctions follows the scaling law β = γ x / ( 1 + γ x ) , with x = ξ / L and γ ≡ γ ( α ) . Here, ξ is the eigenfunction localization length (that we extract from the scaling of Landauer's conductance) and L is the wire length. We also report that for α = 2 the properties of the 1D Anderson model are effectively reproduced.
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Affiliation(s)
- J. A. Méndez-Bermúdez
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
- Correspondence: ; Tel.: +52-222-229-5610
| | - R. Aguilar-Sánchez
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico
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Santonastaso GF, Di Nardo A, Di Natale M, Giudicianni C, Greco R. Scaling-Laws of Flow Entropy with Topological Metrics of Water Distribution Networks. Entropy (Basel) 2018; 20:E95. [PMID: 33265186 DOI: 10.3390/e20020095] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 01/24/2018] [Accepted: 01/26/2018] [Indexed: 11/17/2022]
Abstract
Robustness of water distribution networks is related to their connectivity and topological structure, which also affect their reliability. Flow entropy, based on Shannon's informational entropy, has been proposed as a measure of network redundancy and adopted as a proxy of reliability in optimal network design procedures. In this paper, the scaling properties of flow entropy of water distribution networks with their size and other topological metrics are studied. To such aim, flow entropy, maximum flow entropy, link density and average path length have been evaluated for a set of 22 networks, both real and synthetic, with different size and topology. The obtained results led to identify suitable scaling laws of flow entropy and maximum flow entropy with water distribution network size, in the form of power-laws. The obtained relationships allow comparing the flow entropy of water distribution networks with different size, and provide an easy tool to define the maximum achievable entropy of a specific water distribution network. An example of application of the obtained relationships to the design of a water distribution network is provided, showing how, with a constrained multi-objective optimization procedure, a tradeoff between network cost and robustness is easily identified.
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Ribeiro FL, Meirelles J, Ferreira FF, Neto CR. A model of urban scaling laws based on distance dependent interactions. R Soc Open Sci 2017; 4:160926. [PMID: 28405381 PMCID: PMC5383838 DOI: 10.1098/rsos.160926] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/21/2017] [Indexed: 06/07/2023]
Abstract
Socio-economic related properties of a city grow faster than a linear relationship with the population, in a log-log plot, the so-called superlinear scaling. Conversely, the larger a city, the more efficient it is in the use of its infrastructure, leading to a sublinear scaling on these variables. In this work, we addressed a simple explanation for those scaling laws in cities based on the interaction range between the citizens and on the fractal properties of the cities. To this purpose, we introduced a measure of social potential which captured the influence of social interaction on the economic performance and the benefits of amenities in the case of infrastructure offered by the city. We assumed that the population density depends on the fractal dimension and on the distance-dependent interactions between individuals. The model suggests that when the city interacts as a whole, and not just as a set of isolated parts, there is improvement of the socio-economic indicators. Moreover, the bigger the interaction range between citizens and amenities, the bigger the improvement of the socio-economic indicators and the lower the infrastructure costs of the city. We addressed how public policies could take advantage of these properties to improve cities development, minimizing negative effects. Furthermore, the model predicts that the sum of the scaling exponents of social-economic and infrastructure variables are 2, as observed in the literature. Simulations with an agent-based model are confronted with the theoretical approach and they are compatible with the empirical evidences.
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Affiliation(s)
- Fabiano L. Ribeiro
- Departamento de Física (DFI), Universidade Federal de Lavras (UFLA), Caixa Postal 3037, 37200-000 Lavras, Minas Gerais, Brazil
| | - Joao Meirelles
- Laboratory on Human-Environment Relations in Urban Systems—HERUS, École polytechnique fédérale de Lausanne (EPFL) Station 2, 1015 Lausanne, Switzerland
| | - Fernando F. Ferreira
- EACH—Universidade de São Paulo (USP), Av. Arlindo Bettio, 1000 (Vila Guaraciaba), 03828-000 São Paulo, SP, Brazil
| | - Camilo Rodrigues Neto
- EACH—Universidade de São Paulo (USP), Av. Arlindo Bettio, 1000 (Vila Guaraciaba), 03828-000 São Paulo, SP, Brazil
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Gong Y, Feng Y, Chen X, Tan W, Huo Y, Kassab GS. Intraspecific scaling laws are preserved in ventricular hypertrophy but not in heart failure. Am J Physiol Heart Circ Physiol 2016; 311:H1108-H1117. [PMID: 27542405 PMCID: PMC6347071 DOI: 10.1152/ajpheart.00084.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022]
Abstract
It is scientifically and clinically important to understand the structure-function scaling of coronary arterial trees in compensatory (e.g., left and right ventricular hypertrophy, LVH and RVH) and decompensatory vascular remodeling (e.g., congestive heart failure, CHF). This study hypothesizes that intraspecific scaling power laws of vascular trees are preserved in hypertrophic hearts but not in CHF swine hearts. To test the hypothesis, we carried out the scaling analysis based on morphometry and hemodynamics of coronary arterial trees in moderate LVH, severe RVH, and CHF compared with age-matched respective control hearts. The scaling exponents of volume-diameter, length-volume, and flow-diameter power laws in control hearts were consistent with the theoretical predictions (i.e., 3, 7/9, and 7/3, respectively), which remained unchanged in LVH and RVH hearts. The scaling exponents were also preserved with an increase of body weight during normal growth of control animals. In contrast, CHF increased the exponents of volume-diameter and flow-diameter scaling laws to 4.25 ± 1.50 and 3.15 ± 1.49, respectively, in the epicardial arterial trees. This study validates the predictive utility of the scaling laws to diagnose vascular structure and function in CHF hearts to identify the borderline between compensatory and decompensatory remodeling.
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Affiliation(s)
- Yanjun Gong
- Department of Cardiology, Peking University First Hospital, Beijing, China
| | - Yundi Feng
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Xudong Chen
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Wenchang Tan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
- Shenzhen Graduate School, Peking University, Shenzhen, China
- PKU-HKUST Shenzhen-Hongkong Institute, Shenzhen, China; and
| | - Yunlong Huo
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China;
- College of Medicine, Hebei University, Baoding, China
- PKU-HKUST Shenzhen-Hongkong Institute, Shenzhen, China; and
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Abstract
Understanding cities is central to addressing major global challenges from climate change to economic resilience. Although increasingly perceived as fundamental socio-economic units, the detailed fabric of urban economic activities is only recently accessible to comprehensive analyses with the availability of large datasets. Here, we study abundances of business categories across US metropolitan statistical areas, and provide a framework for measuring the intrinsic diversity of economic activities that transcends scales of the classification scheme. A universal structure common to all cities is revealed, manifesting self-similarity in internal economic structure as well as aggregated metrics (GDP, patents, crime). We present a simple mathematical derivation of the universality, and provide a model, together with its economic implications of open-ended diversity created by urbanization, for understanding the observed empirical distribution. Given the universal distribution, scaling analyses for individual business categories enable us to determine their relative abundances as a function of city size. These results shed light on the processes of economic differentiation with scale, suggesting a general structure for the growth of national economies as integrated urban systems.
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Affiliation(s)
- Hyejin Youn
- Institute for New Economic Thinking, University of Oxford, Oxford OX2 6ED, UK Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | | | - José Lobo
- The Center for Social Dynamics and Complexity, Arizona State University, Tempe, AZ 85281, USA School of Sustainability, Arizona State University, Tempe, AZ 85281, USA
| | - Deborah Strumsky
- Santa Fe Institute Center for Biosocial Complex Systems, Arizona State University, Tempe, AZ 85281, USA
| | - Horacio Samaniego
- Instituto de Conservación, Biodiversidad y Territorio, Universidad Austral de Chile, Valdivia, Chile Instituto de Ecología y Biodiversidad, Casilla 653, Santiago, Chile
| | - Geoffrey B West
- Institute for New Economic Thinking, University of Oxford, Oxford OX2 6ED, UK Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA Mathematics Department, Imperial College, London SW7 2AZ, UK
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50
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Abstract
One of the most celebrated findings in complex systems in the last decade is that different indexes y (e.g. patents) scale nonlinearly with the population x of the cities in which they appear, i.e. y∼x (β) ,β≠1. More recently, the generality of this finding has been questioned in studies that used new databases and different definitions of city boundaries. In this paper, we investigate the existence of nonlinear scaling, using a probabilistic framework in which fluctuations are accounted for explicitly. In particular, we show that this allows not only to (i) estimate β and confidence intervals, but also to (ii) quantify the evidence in favour of β≠1 and (iii) test the hypothesis that the observations are compatible with the nonlinear scaling. We employ this framework to compare five different models to 15 different datasets and we find that the answers to points (i)-(iii) crucially depend on the fluctuations contained in the data, on how they are modelled, and on the fact that the city sizes are heavy-tailed distributed.
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