Digital Eye Strain- A Comprehensive Review

Digital eye strain (DES) is an entity encompassing visual and ocular symptoms arising due to the prolonged use of digital electronic devices. It is characterized by dry eyes, itching, foreign body sensation, watering, blurring of vision, and headache. Non-ocular symptoms associated with eye strain include stiff neck, general fatigue, headache, and backache. A variable prevalence ranging from 5 to 65% has been reported in the pre-COVID-19 era. With lockdown restrictions during the pandemic, outdoor activities were restricted for all age groups, and digital learning became the norm for almost 2 years. While the DES prevalence amongst children alone rose to 50-60%, the symptoms expanded to include recent onset esotropia and vergence abnormalities as part of the DES spectrum. New-onset myopia and increased progression of existing myopia became one of the most significant ocular health complications. Management options for DES include following correct ergonomics like reducing average daily screen time, frequent blinking, improving lighting, minimizing glare, taking regular breaks from the screen, changing focus to distance object intermittently, and following the 20-20-20 rule to reduce eye strain. Innovations in this field include high-resolution screens, inbuilt antireflective coating, matte-finished glass, edge-to-edge displays, and image smoothening graphic effects. Further explorations should focus on recommendations for digital screen optimization, novel spectacle lens technologies, and inbuilt filters to optimize visual comfort. A paradigm shift is required in our understanding of looking at DES from an etiological perspective, so that customized solutions can be explored accordingly. The aim of this review article is to understand the pathophysiology of varied manifestations, predisposing risk factors, varied management options, along with changing patterns of DES prevalence post COVID-19.

Hybrid evolution repeats itself across environmental contexts in Texas sunflowers (Helianthus)

To what extent is evolution repeatable? Little is known about whether the evolution of hybrids is more (or less) repeatable than that of nonhybrids. We used field experimental evolution in annual sunflowers (Helianthus) in Texas to ask the extent to which hybrid evolution is repeatable across environments compared to nonhybrid controls. We created hybrids between Helianthus annuus (L.) and H. debilis (Nutt.) and grew plots of both hybrids and nonhybrid controls through eight generations at three sites in Texas. We collected seeds from each generation and grew each generation × treatment × home site combination at two final common gardens. We estimated the strength and direction of evolution in terms of fitness and 24 traits, tested for repeated versus nonrepeated evolution, and assessed overall phenotypic evolution across lineages and in relation to a locally adapted phenotype. Hybrids consistently evolved higher fitness over time, while controls did not, although trait evolution varied in strength across home sites. Repeated evolution was more evident in hybrids versus nonhybrid controls, and hybrid evolution was often in the direction of the locally adapted phenotype. Our findings have implications for both the nature of repeatability in evolution and the contribution of hybridization to evolution across environmental contexts.

Hotel Revenue Convergence: Evidence Across Star Hotels in Chinese Provinces

This paper analyses, for the first time, potential convergence patterns of hotel revenues across provinces in China. Through the club clustering methodology, the analysis uses a unique dataset of all hotels across all Chinese provinces. The findings document that these hotel revenues follow a diverging pattern on a national level, while a converging pattern is identified across certain provinces, thus forming specific clubs. When the analysis is extended to identify potential drivers for such diverging or converging behavior, the new results illustrate the role of productivity trends, management strategies and tax policies as those factors that drive such patterns. The results could be of substantial value, primarily for tourism policymakers to further improve the current framework of the Chinese hotel industry to introduce practices and policies that will allow the industry to catch up with the global market.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11293-022-09745-6.

Aero-engine health degradation estimation based on an underdetermined extended Kalman filter and convergence proof

In order to improve the reliability of aero-engine, reduce maintenance cost, and promote aircraft safety, lots of attention is paid to health monitoring of aero-engine. The aero-engine gas components involve flow and efficiency parameters, which are key health parameters to obtain the aero-engine' performance degradation. A challenge has to be faced is that these health parameters needed to know are more than the available sensors, which cannot be estimated by the ordinary estimator like Kalman Filter (KF) and Extended Kalman Filter (EKF). In this paper, a system approach is raised to use model tuning parameter to solve the estimation problem mentioned before. To implement it, an underdetermined EKF estimator is constructed from previous achievement and applied to an aero-engine for health state estimation, to address the problem that there are fewer sensor data available with more unknown health parameters. And convergence proof of underdetermined EKF is also provided to make sure that the experimental result is deterministic rather than occasional, deducing that the convergence of this estimator can be verified with some mild constraints. It is found in this study that the covariance matrices Q_k and R_k can meet the conditions of linear matrix inequality (LMI) by designing and setting specific ranges, leading to rapid convergence of the estimator. In addition, semi-physical experiments are shown to verify the feasibility of the proposed method.

Convergence of energy carbon emission efficiency: evidence from manufacturing sub-sectors in China

With China's economy entering the stage of high-quality development, manufacturing energy carbon emission efficiency has become the focus of academic attention. It is of great significance to study the convergence of manufacturing energy carbon emission efficiency for realizing high-quality development of manufacturing in China. Based on the panel data of China's manufacturing sub-sectors, this paper measures and analyzes the evolution trend of manufacturing energy carbon emission and its efficiency. On this basis, this paper uses the coefficient of variation and convergence model to test the convergence of manufacturing energy carbon emission efficiency. The results show that China's manufacturing energy carbon emissions and its efficiency demonstrate an increasing trend. Coal was the main source of manufacturing energy carbon emissions. The manufacturing energy carbon emission efficiency does not have σ convergence, but has [Formula: see text] convergence, and its convergence has industry heterogeneity. The manufacturing energy carbon emission efficiency exits scale effect and technology effect, but not the effect of opening to the outside world and institutional effect, and its effect exists industry heterogeneity. By reducing carbon emissions, adopting differentiated policies, adjusting the industry scale, and enhancing the industry technology intensity, China's manufacturing can improve the energy carbon emission efficiency and promote high-quality economic development.

Klebsiella species: Taxonomy, hypervirulence and multidrug resistance

Members of the genus Klebsiella have rapidly evolved within the past decade, generating organisms that simultaneously exhibit both multidrug resistance and hypervirulence (MDR-hv) phenotypes; such organisms are associated with severe hospital- and community-acquired infections. Carbapenem-resistant infections with unknown optimal treatment regime were of particular concern among the MDR-hv Klebsiella strains. Recent studies have revealed the molecular features and the mobile resistance elements they harbour, allowing identification of genetic loci responsible for transmission, stable inheritance, and expression of mobile resistance or virulence-encoding elements that confer the new phenotypic characteristics of MDR-hv Klebsiella spp. Here, we provide a comprehensive review on the taxonomic position, species composition and different phylotypes of Klebsiella spp., describing the diversity and worldwide distribution of the MDR-hv clones, the genetic mutation and horizontal gene transfer events that drive the evolution of such clones, and the potential impact of MDR-hv infections on human health.

Hands-off? Lessons from high-touch professionals about going virtual

The COVID-19 crisis has fundamentally changed how many businesses operate and connect with their customers. Previously unheard-of government restrictions and sheltering-in-place requirements forced most professional services to transition to remote delivery methods (e.g., email, telephone, video consults, Shopify storefronts). Providers of low-touch services (e.g., lawyers, accountants) naturally lent themselves to remote delivery; however, those that offer high-touch services, particularly those in healthcare (e.g., doctors, chiropractors, physical therapists), experienced a drastic change in working conditions when going virtual. Despite a long history of resistance to virtual delivery, the pandemic created an unprecedented incentive for these high-touch professionals to experiment with underutilized care models such as telehealth: the provision of healthcare services remotely using telecommunications technologies. We examine the rapid adoption of telehealth during COVID-19 through the coming together or convergence of previously unrelated technologies, spaces, and practices. Our analysis reveals opportunities and challenges associated with going hands-off that apply to many other professionals providing high-trust services. Specifically, we offer nine guiding principles for building and protecting cognitive and affective trust in virtual and hybrid delivery models. This is important given the pace of compounding technology convergences that lie ahead for service professionals.

Is there any convergence in the CO2 emission efficiency of airlines?

This paper examines the CO₂ emission efficiency of airlines in the years 2011 and 2018 by using the Atmosfair Airline Index. This index gives reliable results since it encompasses data from more than 100 airlines and considers important variables in the calculation of CO₂ emissions. Firstly, we investigate the regional differences and the effect of the share of government ownership in the CO₂ emission efficiency of airlines. These factors have not been taken into account in other studies by using such a comprehensive index. Secondly, by utilizing the Barro and Sala-i Martin model that is commonly used to examine the regional income convergence model in economics, we also check whether there is a convergence in the CO₂ emission efficiency of airlines or not. As a result, in terms of efficiency growth, we find that airlines in Europe are more successful compared to airlines from other regions. Furthermore, increases in the share of government ownership in airlines negatively affect the CO₂ emission efficiency in Asia, whereas it is insignificant in Europe and America. Moreover, there is no convergence in the CO₂ emission efficiency of airlines from all regions. This shows that low-efficient airlines are not catching up with high-efficient airlines. Lastly, we find that charter airlines are more efficient in terms of CO₂ emissions.

Convergent movement of COVID-19 outbreak in Japan based on SIR model

The infection dynamics of COVID-19 show frequent phases in which the infection spreads rapidly, resembling explosive infection. However, despite the repeated increases and decreases, there is a process of convergence even within a relatively short period of time. While it is obvious that the growth rate of the cumulative number of infected people slows down as it increases, considering the infectious disease process, we also observe a slowdown in the growth rate of the net number of infected people. Moreover, there exists a special type of convergence whereby areas with initially many infected people exhibit low rates of increase in the numbers of infected people subsequently. This paper uses prefectural panel data from Japan through March 2021 to confirm the convergence process.

A unified theory and evidence on CO2 emissions convergence

The objective of this paper is to develop and test a sound theory of CO₂ emissions convergence equation. To this end, we modify the Solow growth model by including depleting energy as a factor of production and by defining the channel through which CO₂ emissions are created. Then, we empirically estimate the derived per capita CO₂ emissions convergence equation employing system GMM approach on a panel dataset of 65 countries over the period 1970 to 2014. Results present strong evidence towards the existence of convergence for the global sample over the whole period. We also find that, in terms of per capita CO₂ emissions, Annex I parties of UNFCCC converge, while non-Annex countries diverge. Our robustness check via stochastic convergence tests confirms our system GMM results for Annex I countries.

Guest-Dependent Isomer Convergence of a Permanently Fluxional Coordination Cage

A fluxional bis-monodentate ligand, based on the archetypal shape-shifting molecule bullvalene, self-assembles with M2+ (M=Pd2+ or Pt2+ ) to produce a highly complex ensemble of permanently fluxional coordination cages. Metal-mediated self-assembly selects for an M2 L4 architecture while maintaining shape-shifting ligand complexity. A second level of simplification is achieved with guest-exchange; the binding of halides within the M2 L4 cage mixture results in a convergence to a cage species with all four ligands present as the "B isomer". Within this confine, the reaction graph of the bullvalene is greatly restricted, but gives rise to a mixture of 38 possible diastereoisomers in rapid exchange. X-ray crystallography reveals a preference for an achiral form consisting of both ligand enantiomers. Through a combination of NMR spectroscopy and DFT calculations, we elucidate the restricted isomerisation pathway of the permanently fluxional M2 L4 assembly.

Pattern formation features might explain homoplasy: fertile surfaces in higher fungi as an example

Fungi show a high degree of morphological convergence. Regarded for a long time as an obstacle for phylogenetic studies, homoplasy has also been proposed as a source of information about underlying morphogenetic patterning mechanisms. The "local-activation and long-range inhibition principle" (LALIP), underlying the famous reaction-diffusion model proposed by Alan Turing in 1952, appears to be one of the universal phenomena that can explain the ontogenetic origin of seriate patterns in living organisms. Reproductive structures of fungi in the class Agaricomycetes show a highly periodic structure resulting in, for example, poroid, odontoid, lamellate or labyrinthic hymenophores. In this paper, we claim that self-organized patterns might underlie the basic ontogenetic processes of these structures. Simulations based on LALIP-driven models and covering a wide range of parameters show an absolute mutual correspondence with the morphospace explored by extant agaricomycetes. This could not only explain geometric particularities but could also account for the limited possibilities displayed by hymenial configurations, thus making homoplasy a direct consequence of the limited morphospace resulting from the proposed patterning dynamics.

The Cause of Alzheimer's Disease: The Theory of Multipathology Convergence to Chronic Neuronal Stress

The field of Alzheimer's disease (AD) research critically lacks an all-inclusive etiology theory that would integrate existing hypotheses and explain the heterogeneity of disease trajectory and pathologies observed in each individual patient. Here, we propose a novel comprehensive theory that we named: the multipathology convergence to chronic neuronal stress. Our new theory reconsiders long-standing dogmas advanced by previous incomplete theories. Firstly, while it is undeniable that amyloid beta (Aβ) is involved in AD, in the seminal stage of the disease Aβ is unlikely pathogenic. Instead, we hypothesize that the root cause of AD is neuronal stress in the central nervous system (CNS), and Aβ is expressed as part of the physiological response to protect CNS neurons from stress. If there is no return to homeostasis, then Aβ becomes overexpressed, and this includes the generation of longer forms that are more toxic and prone to oligomerization. Secondly, AD etiology is plausibly not strictly compartmentalized within the CNS but may also result from the dysfunction of other physiological systems in the entire body. This view implies that AD may not have a single cause, but rather needs to be considered as a spectrum of multiple chronic pathological modalities converging to the persistent stressing of CNS neurons. These chronic pathological modalities, which include cardiovascular disease, metabolic disorders, and CNS structural changes, often start individually, and over time combine with other chronic modalities to incrementally escalate the amount of stress applied to CNS neurons. We present the case for considering Aβ as a marker of neuronal stress in response to hypoxic, toxic, and starvation events, rather than solely a marker of AD. We also detail numerous human chronic conditions that can lead to neuronal stress in the CNS, making the link with co-morbidities encountered in daily clinical AD practice. Finally, we explain how our theory could be leveraged to improve clinical care for AD and related dementia in personalized medicine paradigms in the near future.

Approaching biology through the retrocausal apex in physics

Quantum stochasticity carries two incompatible implications. One is for the statistical divergence upon the prior absence of complete controllability over boundary conditions applied to mechanistic causation. One more alternative is for the statistical convergence upon the posterior decidability of measurement despite the absence of the prior decidability. Decidable measurement lacking the prior decidability is retrocausal. The quantum physical likelihood for the life world may derive from the statistical convergence proceeding in a durable manner. This observation suggests that there must have been some type of observers even internal to the lifeless world, otherwise no likelihood of identifying the objects of interest could be available there. Measurement activity intrinsic to the internal observers is indexical, while the similar activity specific to the external observer like us can be symbolic. The difference is in the phenomenological qualification since both are the observers of different types. A most conspicuous case demonstrating the phenomenological difference is revealed in the different nature of time to be employed and experienced there. Time serves as a principal attribute qualifying the phenomenon to be experienced as such. Qualification of time is observer dependent.

The Impact of L2 English Learners' Belief about an Interlocutor's English Proficiency on L2 Phonetic Accommodation

The current study investigates the influence of L2 English learners' belief about their interlocutor's English proficiency on phonetic accommodation and explores whether interaction-induced phonetic convergence could improve L2 English learners' vowel pronunciation. Results from two experiments show that when the subjects believed that their interlocutor was a native English speaker, they generally converged to her vowel pronunciation. When the subjects believed that their interlocutor was a non-native English speaker, they generally diverged from her vowel pronunciation. In addition, phonetic convergence enabled the subjects to improve their L2 English vowel pronunciation, leading to greater similarity to the native interlocutor. The findings are discussed in terms of the Communication Accommodation Theory, the Interactive Alignment Theory, and the Speech Learning Model.

Symptomic Mimicry Between SARS-CoV-2 and the Common Cold Complex

The recent changes in COVID-19 symptoms suggest convergent evolution of respiratory diseases. This process is analogous to the emergence of animal mimetic complexes and complements previously identified types of mimicry. A novel pathogen might go unnoticed or insufficiently counteracted if it resembles a disease that the host already faced on multiple occasions, which creates a selective pressure towards a typical symptomic phonotype. In short, the reason why so many unrelated pathogens cause similar symptoms may correspond to the reasons that drove the evolution of the 'warning' wasp-like colouration in various insect species.

The effect of convergent action on reducing stunting prevalence in under-five children in Banggai District, Central Sulawesi, Indonesia

OBJECTIVE

This study aimed to assess the amount of changes in prevalence of stunting after one-year convergence intervention.

METHODS

This was an evaluation study of national program that implemented in Banggai District beginning 2018. There were ten villages (n=532) that included in the program based on severity of stunting prevalence. Data were analyzed using chi-square and independent t-test using SPSS.

RESULT

After a year program, stunting reduced to 38.91% or 2.18% from the baseline (41.09%). The highest reduction was in at 0-5 mo (8.59%) and 6-11 mo (8.46%). There was no difference using height for age z-score in all ages (-1.64±1.19 to -1.59±1.38, p=0.506). However, the reduction was significant at 0-11 months (-1.20±1.23 to 0.78±1.58, p=0.020) but no in other age categories (p>0.05).

CONCLUSION

The convergence action for one year intervention reduced significantly stunting in 0-11 months of children but not in other age categories of under five children.

The Nurse+Engineer as the Prototype V-Shaped Professional

BACKGROUND

Descriptions of convergence research include promises to solve complex societal problems, such as environmental determinants of health and social determinants of health, through the integration of diverse disciplines, such as nursing and engineering, to create novel frameworks, such as the V-shaped professional.

PURPOSE

The purpose of this paper was to define the nurse+engineer as a prototypical V-shaped professional.

METHODS

Starting from a description of the I-shaped discipline of nursing and the I-shaped discipline of engineering, we follow an intentional pathway to define the concept of the nurse+engineer as a new V-shaped professional.

FINDINGS

Examples of the nurse+engineer at the bedside and the nurse+engineer in the community are highlighted to support a theoretical definition of the V-shaped nurse+engineer.

DISCUSSION

Implications of the nurse+engineer in the workforce and practical recommendations for training nurse+engineer professionals are provided to improve healthcare policy, practice, research, and education through scientific discovery and innovation.

From convergence to divergence: Lifespan variation in US states, 1959-2017

BACKGROUND

Large disparities in life expectancy exist across US states and the gaps have been widening in recent decades. Less is known about the lifespan variability - a measure that can provide important insights into mortality inequalities both between and within states.

METHOD

Using yearly lifetables from the United States Mortality Database, we explore geographic and temporal patterns in lifespan variation (unconditional and conditional on survival to age 10, 35 and 65) across US states between 1959 and 2017. We also examine the contribution of state differences in life expectancy to overall lifespan variation using standard decomposition techniques.

RESULTS

Despite overall convergence in lifespan variation across states over the last six decades, in more recent years there has been notable divergence. Gender-specific analyses show that lifespan variation was generally greater among males than among females; but this pattern reverses for mortality past age 65. Much of the state disparities in lifespan variation, unconditional and conditional on survival to age 10 and 35, were due to mortality differences under the age 65. Decomposition analysis shows that while within-state variability remains the primary driver of overall lifespan variation, the contribution of cross-state differences in life expectancy is growing.

CONCLUSIONS

Variation in longevity is greater within US States than between them, yet cross-states disparities in mortality are increasing. This likely reflects the long-term consequences of rising social, economic, and political stratification for health inequalities both within and across states.

Sustainable water and sanitation for all: Are we there yet?

The lack of access to water and sanitation services (WSS) of a considerable share of the world population has been challenging the international community for decades. The proposal of the Millennium Development Goals and, later on, the Sustainable Development Goals (SDGs) by the United Nations (UN) intended to act as a blueprint to achieve a more equitable future for all and, in the case of WSS, "Ensure the availability and sustainable management of water and sanitation for all" (SDG 6). However, the current global pandemic further emphasised the importance of WSS, given the increasing asymmetries faced by billions worldwide, and the gaps between high-income and low- and middle-income nations. For this reason, understanding whether low- and middle-income countries have been approximating towards or deviating from the SDG 6 is crucial to derive and communicate key information for the sake of improved public governance and political decision-making. In this paper, we extend a state-of-the-art methodology based on data envelopment analysis for assessing the convergence of the low- and middle-income UN Member States regarding the SDG 6 between 2016 and 2017. We find that, on average, not only did the Member States converge by decreasing the performance spread and the gap between the best and worst practice frontiers, but also the Level of water stress: freshwater withdrawal as a proportion of available freshwater resources was the indicator in which the majority exhibited the worst performances. In the end, we derive possible policy implications, which, as our results show, are aligned with the recent UN reports on the subject.

The Short-Term Effects of European Integration on Mortality Convergence: A Case Study of European Union's 2004 Enlargement

Although European integration can be expected to result in mortality convergence (reduced mortality differences), a life expectancy divide persists in the European Union (EU) between the old Member States (OMS) in the west and the new Member States (NMS) in the east. Studies investigating the impact of European integration on mortality convergence are rare and did not consider regional differences. We examine the short-term effects of the 2004 enlargement on mortality convergence at the supranational, national, and subnational levels. Using sex-specific life expectancies for 23 Member States (1990-2017) and the NUTS 2 regions in Czechia, Hungary, and Poland for 1992-2016, we examined the trend in sigma and beta mortality convergence measures at the country and regional levels using joinpoint regression. We found no compelling evidence that EU accession influenced the process of mortality convergence between OMS and NMS, or within the three NMS, over the short term. While there was overall beta and sigma convergence at the national level during 1990-2017, no regional convergence showed, and the trends in convergence did not significantly change at the time of EU accession or soon after (2004-2007). The accession in 2004 did not visibly impact the overall process of mortality convergence over the short term, likely because of the greater influence of country and region-specific policies and characteristics. The interaction of Member State and regional contexts with the mechanisms of European integration requires further study. Future enlargement procedures should emphasise tailored support to ensure more equitable gains from European integration.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10680-021-09596-y.

Evolving Views on the Pallium

The pallium is the largest part of the telencephalon in amniotes, and comparison of its subdivisions across species has been extremely difficult and controversial due to its high divergence. Comparative embryonic genoarchitecture studies have greatly contributed to propose models of pallial fundamental divisions, which can be compared across species and be used to extract general organizing principles as well as to ask more focused and insightful research questions. The use of these models is crucial to discern between conservation, convergence or divergence in the neural populations and networks found in the pallium. Here we provide a critical review of the models proposed using this approach, including tetrapartite, hexapartite and double-ring models, and compare them to other models. While recognizing the power of these models for understanding brain architecture, development and evolution, we also highlight limitations and comment on aspects that require attention for improvement. We also discuss on the use of transcriptomic data for understanding pallial evolution and advise for better contextualization of these data by discerning between gene regulatory networks involved in the generation of specific units and cell populations versus genes expressed later, many of which are activity dependent and their expression is more likely subjected to convergent evolution.

How to use the Delphi method to aid in decision making and build consensus in pharmacy education

OUR SITUATION

As pharmacy educators, we often encounter situations such as designing new curricula or establishing shared values for an organization that may be ambiguous or controversial. To generate effective solutions, it is often necessary to build group consensus with key stakeholders. The purpose of this paper is to describe and provide recommendations for using the Delphi method, a process for facilitating discussions and aiding in decision making.

METHODOLOGICAL LITERATURE REVIEW

An overview of the Delphi method, including its multiple variations, is presented. Steps necessary to complete a Delphi study (building a protocol, developing a research question, defining panelists and panel size, piloting the protocol, round one item creation and analysis, round two and beyond, consensus, increasing clarity, and reporting) is described.

OUR RECOMMENDATIONS AND THEIR APPLICATION(S)

Practical recommendations are provided to support use the Delphi method to build consensus in research. These recommendations include: (1) clarify the purpose of the Delphi, (2) ensure the research questions are grounded in the literature and are relevant, (3) carefully consider panelist processes, (4) determine any definitions that should be given to or developed by panelists, (5) determine methods for enhancing clarity, and (6) employ methods to reduce attrition.

POTENTIAL IMPACT

The Delphi method provides a systematic approach to generating consensus in pharmacy education for commonly encountered situations such as committee meetings, research studies, faculty retreats, classroom activities, and lab meetings.

Development of Explicit Schemes for Diffusive SEAIR COVID-19 Epidemic Spreading Model: An Application to Computational Biology

In this contribution, a first-order time scheme is proposed for finding solutions to partial differential equations (PDEs). A mathematical model of the COVID-19 epidemic is modified where the recovery rate of exposed individuals is also considered. The linear stability of the equilibrium states for the modified COVID-19 model is given by finding its Jacobian and applying Routh-Hurwitz criteria on characteristic polynomial. The proposed scheme provides the first-order accuracy in time and second-order accuracy in space. The stability of the proposed scheme is given using the von Neumann stability criterion for standard parabolic PDEs. The consistency for the proposed scheme is also given by expanding the involved terms in it using the Taylor series. The scheme can be used to obtain the condition of getting a positive solution. The stability region of the scheme can be enlarged by choosing suitable values of the contained parameter. Finally, a comparison of the proposed scheme is made with the existing non-standard finite difference method. The results indicate that the non-standard classical technique is incapable of preserving the unique characteristics of the model's epidemiologically significant solutions, whereas the proposed approaches are capable of doing so. A computational code for the proposed discrete model scheme may be made available to readers upon request for convenience.

Progress in child stunting across the world from 1990 to 2015: testing the global convergence hypothesis

OBJECTIVE

This study has two-fold objectives: first, to test the global convergence hypothesis in the progress of child stunting across 174 countries over the period 1990-2015; second, to identify factors determining the process of convergence or divergence.

DESIGN

The study design comprises macro-level cross-country analyses. Our empirical strategy uses parametric convergence models such as absolute and conditional β-convergence models, while non-parametric convergence models such as Kernel density plots serve as robustness checks.

SETTING

The study uses a global setting comprising child stunting information from 174 countries.

PARTICIPANTS

The participants for this study are 174 countries. The information on child stunting prevalence for most countries is available from the UNICEF-WHO-WB Joint Child Malnutrition Estimates Expanded Database (April-2019), while national-level surveys are used for those countries where UNICEF-WHO-WB Database is not available. The data for socio-economic variables are taken from the World Bank's data bank (1990-2015).

RESULTS

Findings from the absolute β-convergence model estimates show that progress in child stunting has diverged over the entire period (1990-2015). However, the speed of divergence has reduced for the recent period (2010-2015). The conditional β-convergence model estimates show that cross-country heterogeneity in GDP per capita, poverty and health care expenditure are significant factors explaining divergence in child stunting.

CONCLUSIONS

For replacing current divergence with convergence in child stunting worldwide, the study demonstrates the critical role of economic factors and public spending on health care to reduce child stunting, particularly in countries where progress is slow.