Toward Scalable Boson Sampling with Photon Loss

Boson sampling is a well-defined task that is strongly believed to be intractable for classical computers, but can be efficiently solved by a specific quantum simulator. However, an outstanding problem for large-scale experimental boson sampling is the scalability. Here we report an experiment on boson sampling with photon loss, and demonstrate that boson sampling with a few photons lost can increase the sampling rate. Our experiment uses a quantum-dot-micropillar single-photon source demultiplexed into up to seven input ports of a 16×16 mode ultralow-loss photonic circuit, and we detect three-, four- and fivefold coincidence counts. We implement and validate lossy boson sampling with one and two photons lost, and obtain sampling rates of 187, 13.6, and 0.78 kHz for five-, six-, and seven-photon boson sampling with two photons lost, which is 9.4, 13.9, and 18.0 times faster than the standard boson sampling, respectively. Our experiment shows an approach to significantly enhance the sampling rate of multiphoton boson sampling.

Studies of the resonance structure in D 0 → K ∓ π ± π ± π ∓ decays

Amplitude models are constructed to describe the resonance structure of D 0 → K - π + π + π - and D 0 → K + π - π - π + decays using pp collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of 3.0  f b - 1 . The largest contributions to both decay amplitudes are found to come from axial resonances, with decay modes D 0 → a 1 ( 1260 ) + K - and D 0 → K 1 ( 1270 / 1400 ) + π - being prominent in D 0 → K - π + π + π - and D 0 → K + π - π - π + , respectively. Precise measurements of the lineshape parameters and couplings of the a 1 ( 1260 ) + , K 1 ( 1270 ) - and K ( 1460 ) - resonances are made, and a quasi model-independent study of the K ( 1460 ) - resonance is performed. The coherence factor of the decays is calculated from the amplitude models to be R K 3 π = 0.459 ± 0.010 ( stat ) ± 0.012 ( syst ) ± 0.020 ( model ) , which is consistent with direct measurements. These models will be useful in future measurements of the unitary-triangle angle γ and studies of charm mixing and C P violation.

Evidence for the Rare Decay Σ^{+}→pμ^{+}μ^{-}

A search for the rare decay Σ^{+}→pμ^{+}μ^{-} is performed using pp collision data recorded by the LHCb experiment at center-of-mass energies sqrt[s]=7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. An excess of events is observed with respect to the background expectation, with a signal significance of 4.1 standard deviations. No significant structure is observed in the dimuon invariant mass distribution, in contrast with a previous result from the HyperCP experiment. The measured Σ^{+}→pμ^{+}μ^{-} branching fraction is (2.2_{-1.3}^{+1.8})×10^{-8}, where statistical and systematic uncertainties are included, which is consistent with the standard model prediction.

First Search for Nontensorial Gravitational Waves from Known Pulsars

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

A Prospective Validation of National Early Warning Score in Emergency Intensive Care Unit Patients at Beijing

Introduction

National Early Warning Score (NEWS) was launched in 2012 by the Royal College of Physicians in UK with an aim to improve the assessment of critical patients and timely detection of clinical deterioration.

Objective

To assess the performance of NEWS in emergency intensive care unit (EICU) patients in Beijing, PROC.

Design

prospective cohort study.

Setting

EICU in a university hospital.

Methods

The inclusion criteria were patients who stayed in the EICU beds under Department of Emergency Medicine, Xuanwu Hospital of Capital Medical University. Data of patients on admission were collected and calculated NEWS. Main outcome measure was death within 24 hours. The ability to predict mortality was assessed by area under the receiver operating characteristic curve (AUROC) analysis.

Results

Data on 540 consecutive EICU patients were collected from 1st January, 2013 to 31st March, 2013. Scores of 7 or more were associated with increased risk of death (OR=16.8; 95% CI 6.6-42.9). The AUROC for death within 24 h of admission was 0.85 (95% CI 0.79-0.90).

Conclusions

NEWS is applicable and feasible for EICU patients in Beijing. This study shows that the prediction power of NEWS for death within 24 hours of acutely ill patients attending Xuan Wu Hospital is comparable to that reported for the United Kingdom patients. (Hong Kong j.emerg.med. 2015;22:137-144)

Robust thumb flexor tendon repairs with a six-strand M-Tang method, pulley venting, and early active motion

We present the outcomes of flexor pollicis longus tendon repairs in 34 thumbs using a six-strand M-Tang repair with venting of one or two pulleys according to site of tendon laceration. The A2 pulley was vented in all three thumbs with zone 1 injury. In 31 thumbs with zone 2 injuries, the oblique pulley was vented partially or entirely. Twenty-two thumbs had both the A1 and oblique pulleys vented. Six to 46 months post-surgery, 14 thumbs with zone 2 injuries were rated excellent, 13 good, three fair and one failure according to Tang criteria. No tendon ruptures or bowstringing occurred. Fourteen of 34 thumbs had deficits in interphalangeal joint extension averaging 13°. We conclude that venting of one or two pulleys may ensure recovery of thumb function without risking tendon bowstringing and that early active thumb motion is safe with a robust tendon repair.

LEVEL OF EVIDENCE

IV.

Effects of caloric restriction on peroxisome proliferator-activated receptors and positive transcription elongation factor b expression in obese rats

OBJECTIVE

To investigate the effect of caloric restriction (CR) on expressions of peroxisome proliferators-activated receptors (PPARs) and positive transcription elongation factor b (P-TEFb) (including cyclin-dependent kinase 9 (CDK9) and cyclin T1) protein in visceral adipose tissue of obese rats.

MATERIALS AND METHODS

Obese rats were induced by high-fat diet for 8 weeks. Then they were divided into three groups: Model (n=5), 50% Calorie Restricted (50% CR, n=5), Intermittent Fasting (IF) (eight cycles of 3-d fasting and 3-d refeeding, n=6) for 8 weeks. Biochemical parameters were measured. Protein and mRNA expression of Cdk9, cyclin T1 and PPARs were qualified in visceral adipose tissue.

RESULTS

A significant decline in fasting plasma glucose (FPG), homeostatic model assessment of insulin resistance (HOMA-IR), body weight, and visceral fat weight was observed in 50% CR group. The IF group exhibited a significant decrease in FPG, HOMA-IR, visceral fat weight. Both 50% CR and IF down-regulated mRNA and protein expression of PPARγ and Cdk9, cyclin T1 and up-regulated mRNA and protein expression of PPARβ.

CONCLUSIONS

These results suggest that the effects of 50% CR and IF on HOMA-IR, body weight, visceral fat weight, P-TEFb and PPARγ expression may be related to their protective potential on obesity.

Outcomes of Pharmacomechanical Catheter-directed Thrombolysis for Acute and Subacute Inferior Vena Cava Thrombosis: A Retrospective Evaluation in a Single Institution

OBJECTIVE/BACKGROUND

The objective was to assess the mid-term results of pharmacomechanical catheter-directed thrombolysis (PCDT) for symptomatic acute and subacute inferior vena cava (IVC) thrombosis; the risk factors of early thrombosis recurrence and iliocaval patency were also evaluated.

METHODS

From January 2010 to December 2015, 54 patients (33 men; mean age 47.1 years) with symptomatic acute and subacute IVC thrombosis were treated with PCDT. Primary technical success (clot lysis ≥ 50% after PCDT), stent-assisted technical success (residual stenosis < 30% after stenting), clinical success (freedom from thrombosis recurrence within 30 days), complications, frequency of post-thrombotic syndrome (PTS; Villalta score ≥ 5), and iliocaval patency were recorded at follow-up evaluation. A multivariate regression model was used to determine predictors of early thrombosis reoccurrence and iliocaval patency.

RESULTS

The primary technical success and the stent-assisted technical success were 63% (n = 34/54) and 100% (n = 54/54) respectively. There were 11 patients (20%) with immediate recurrent thrombosis requiring repeat PCDT. Minor bleeding complications occurred in seven patients, and one patient with major bleeding needed a blood transfusion. The occurrence of PTS at a mean of 26 months (range 1-60 months) was 13% (7/54). The 3-year primary and secondary iliocaval patency was 63% and 81%, respectively. On multivariate analysis, active malignancy was predictive of immediate IVC thrombosis recurrence (hazard ratio [HR] 5.8, 95% confidence interval [CI] 1.7-19.8; p = .01), whereas the pre-existing filter played a protective role against iliocaval re-occlusion (HR 0.3, 95% CI 0.1-0.8; p = .01).

CONCLUSIONS

PCDT is safe and effective in managing symptomatic acute and subacute IVC thrombosis. Active malignancy is predictor of thrombosis re-occurrence, whereas the presence of a filter is associated with a higher rate of iliocaval patency at mid-term follow-up.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.

A viral microRNA downregulates metastasis suppressor CD82 and induces cell invasion and angiogenesis by activating the c-Met signaling

Kaposi’s sarcoma (KS) is the most common AIDS-associated malignancy etiologically caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). KS is a highly disseminated and vascularized tumor comprised of poorly differentiated spindle-shaped endothelial cells. KSHV encodes 12 pre-microRNAs (pre-miRNAs) that yield 25 mature miRNAs, but their roles in KSHV-induced tumor dissemination and angiogenesis remain largely unknown. KSHV-encoded miR-K12-6 (miR-K6) can produce two mature miRNAs, miR-K6-3p and miR-K6-5p. Recently, we have shown that miR-K6-3p promoted cell migration and angiogenesis by directly targeting SH3 domain binding glutamate-rich protein (SH3BGR) (PLoS Pathog. 2016;12(4):e1005605). Here, by using mass spectrometry, bioinformatics analysis and luciferase reporter assay, we showed that miR-K6-5p directly targeted the coding sequence (CDS) of CD82 molecule (CD82), a metastasis suppressor. Ectopic expression of miR-K6-5p specifically inhibited the expression of endogenous CD82 and strongly promoted endothelial cells invasion in vitro and angiogenesis in vivo. Overexpression of CD82 significantly inhibited cell invasion and angiogenesis induced by miR-K6-5p. Mechanistically, CD82 directly interacted with c-Met to inhibit its activation. MiR-K6-5p directly repressed CD82, relieving its inhibition on c-Met activation and inducing cell invasion and angiogenesis. Deletion of miR-K6 from KSHV genome abrogated KSHV suppression of CD82 resulting in compromised KSHV activation of c-Met pathway, and KSHV-induced invasion and angiogenesis. In conclusion, these results show that by inhibiting CD82, KSHV miR-K6-5p promotes cell invasion and angiogenesis by activating the c-Met pathway. Our findings illustrate that KSHV miRNAs may play an essential role in the dissemination and angiogenesis of KSHV-induced malignancies.

Time-Bin-Encoded Boson Sampling with a Single-Photon Device

Boson sampling is a problem strongly believed to be intractable for classical computers, but can be naturally solved on a specialized photonic quantum simulator. Here, we implement the first time-bin-encoded boson sampling using a highly indistinguishable (∼94%) single-photon source based on a single quantum-dot-micropillar device. The protocol requires only one single-photon source, two detectors, and a loop-based interferometer for an arbitrary number of photons. The single-photon pulse train is time-bin encoded and deterministically injected into an electrically programmable multimode network. The observed three- and four-photon boson sampling rates are 18.8 and 0.2 Hz, respectively, which are more than 100 times faster than previous experiments based on parametric down-conversion.

miR-138 suppressed the progression of osteoarthritis mainly through targeting p65

OBJECTIVE

MicroRNAs are reported to play key roles in regulating the main risk factors for osteoarthritis (OA) chondrogenesis. In the current study, we focused on miR-138, which has never been explored in OA.

PATIENTS AND METHODS

The expression of miR-138 and p65 was explored in the cartilage tissues of OA patients and compared with those of normal controls. We then explored the effects of miR-138 on NF-κB signaling activation in both human OA chondrocytes and chondrogenic SW1353 cells in the presence of 10 nM TNFα. The protein levels of p65, COX-2 and IL6 were determined using Western blot analysis. To validate the target gene of miR-138, a dual luciferase reporter assay was performed.

RESULTS

The level of miR-138 was markedly reduced in the OA cartilage tissues compared with those of normal controls. Real-time PCR analysis demonstrated that the level of miR-138 decreased after TNFα treatment for 3, 6, and 12 h in the normal chondrocytes and OA chondrocytes. Furthermore, overexpression of miR-138 suppressed the protein levels of p65, COX-2 and IL6 in human OA chondrocytes and chondrogenic SW1353 cells. A dual luciferase reporter assay demonstrated that miR-138 significantly suppressed the relative luciferase activity of pmirGLO-p65-3'UTR. More importantly, treatment with TNFα significantly enhanced the protein levels of p65, COX-2 and IL6. However, overexpression of miR-138 could partially abolish such effects.

CONCLUSIONS

We demonstrated that reduced miR-138 expression enhanced the destruction of the cartilage tissues among OA patients, mainly through targeting p65.

Upper Limits on the Stochastic Gravitational-Wave Background from Advanced LIGO's First Observing Run

A wide variety of astrophysical and cosmological sources are expected to contribute to a stochastic gravitational-wave background. Following the observations of GW150914 and GW151226, the rate and mass of coalescing binary black holes appear to be greater than many previous expectations. As a result, the stochastic background from unresolved compact binary coalescences is expected to be particularly loud. We perform a search for the isotropic stochastic gravitational-wave background using data from Advanced Laser Interferometer Gravitational Wave Observatory's (aLIGO) first observing run. The data display no evidence of a stochastic gravitational-wave signal. We constrain the dimensionless energy density of gravitational waves to be Ω_{0}<1.7×10^{-7} with 95% confidence, assuming a flat energy density spectrum in the most sensitive part of the LIGO band (20-86 Hz). This is a factor of ∼33 times more sensitive than previous measurements. We also constrain arbitrary power-law spectra. Finally, we investigate the implications of this search for the background of binary black holes using an astrophysical model for the background.

Directional Limits on Persistent Gravitational Waves from Advanced LIGO's First Observing Run

We employ gravitational-wave radiometry to map the stochastic gravitational wave background expected from a variety of contributing mechanisms and test the assumption of isotropy using data from the Advanced Laser Interferometer Gravitational Wave Observatory's (aLIGO) first observing run. We also search for persistent gravitational waves from point sources with only minimal assumptions over the 20-1726 Hz frequency band. Finding no evidence of gravitational waves from either point sources or a stochastic background, we set limits at 90% confidence. For broadband point sources, we report upper limits on the gravitational wave energy flux per unit frequency in the range F_{α,Θ}(f)<(0.1-56)×10^{-8}    erg cm^{-2} s^{-1} Hz^{-1}(f/25  Hz)^{α-1} depending on the sky location Θ and the spectral power index α. For extended sources, we report upper limits on the fractional gravitational wave energy density required to close the Universe of Ω(f,Θ)<(0.39-7.6)×10^{-8}  sr^{-1}(f/25  Hz)^{α} depending on Θ and α. Directed searches for narrowband gravitational waves from astrophysically interesting objects (Scorpius X-1, Supernova 1987 A, and the Galactic Center) yield median frequency-dependent limits on strain amplitude of h_{0}<(6.7,5.5,  and  7.0)×10^{-25}, respectively, at the most sensitive detector frequencies between 130-175 Hz. This represents a mean improvement of a factor of 2 across the band compared to previous searches of this kind for these sky locations, considering the different quantities of strain constrained in each case.

[Simulation study of air quality health index in 5 cities in China: 2013-2015]

Objective: To construct the air quality health index (AQHI) by inclusion of air pollutants PM(2.5) and O(3) in Guangzhou, Shanghai, Xi' an, Beijing, Shenyang, and explore scientificity and feasibility of its application in China. Methods: The daily average concentrations of PM(2.5) and O(3) in air, and daily average mortality from 2013 to 2015 in the 5 cities in China, the exposure-response coefficients of PM(2.5) and O(3) and total mortality from Meta studies in China were used to construct local AQHI. The health risk levels of air pollution in the 5 cities were calculated and compared with the characteristics of single pollutant concentrationof PM(2.5) or O(3). Results: In the 5 cities, the average concentration of PM(2.5) was highest in Beijing (82 μg/m(3)) and lowest in Guangzhou (46 μg/m(3)). And the average concentration of O(3) was highest in Shanghai (72 μg/m(3)) and lowest in Xi' an (45 μg/m(3)). In all the cities, the average concentration of PM(2.5) was highest in winter and lowest in summer. In summer, the average concentration of O(3) was lowest. But the health risk level of AQHI showed that the 5 cities had higher frequency of low or medium risk averagely. And Beijing had the highest frequency of high risk in summer (5.69%). Xi' an had the highest frequency of extremely high risk in winter (1.63%). Conclusions: In this study, AQHI could be constructed by using air PM(2.5) and O(3) concentration data which can be obtained in many areas in China. The application of this index is scientific and feasible in China.