Second-order optimization strategies for neural network quantum states

The Variational Monte Carlo (VMC) method has recently seen important advances through the use of neural network quantum states. While more and more sophisticated ansatze have been designed to tackle a wide variety of quantum many-body problems, modest progress has been made on the associated optimization algorithms. In this work, we revisit the Kronecker-Factored Approximate Curvature (KFAC), an optimizer that has been used extensively in a variety of simulations. We suggest improvements in the scaling and the direction of this optimizer and find that they substantially increase its performance at a negligible additional cost. We also reformulate the VMC approach in a game theory framework, to propose a novel optimizer based on decision geometry. We find that on a practical test case for continuous systems, this new optimizer consistently outperforms any of the KFAC improvements in terms of stability, accuracy and speed of convergence. Beyond VMC, the versatility of this approach suggests that decision geometry could provide a solid foundation for accelerating a broad class of machine learning algorithms. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'.

Nuclear shell-model simulation in digital quantum computers

The nuclear shell model is one of the prime many-body methods to study the structure of atomic nuclei, but it is hampered by an exponential scaling on the basis size as the number of particles increases. We present a shell-model quantum circuit design strategy to find nuclear ground states by exploiting an adaptive variational quantum eigensolver algorithm. Our circuit implementation is in excellent agreement with classical shell-model simulations for a dozen of light and medium-mass nuclei, including neon and calcium isotopes. We quantify the circuit depth, width and number of gates to encode realistic shell-model wavefunctions. Our strategy also addresses explicitly energy measurements and the required number of circuits to perform them. Our simulated circuits approach the benchmark results exponentially with a polynomial scaling in quantum resources for each nucleus. This work paves the way for quantum computing shell-model studies across the nuclear chart and our quantum resource quantification may be used in configuration-interaction calculations of other fermionic systems.

Peroxynitrite-Induced Intracellular Ca2+ Depression in Cardiac Myocytes: Role of Sarco/Endoplasmic Reticulum Ca2+ Pump

Several studies have shown that peroxynitrite (ONOO-), formed upon the reaction of •NO and O2-, is increased in many cardiovascular diseases and is detrimental to myocardial function. Proteins associated with Ca2+ homeostasis regulation in the heart may be involved in these effects. Thus, the aim of this study was to elucidate the mechanisms associated with ONOO--induced effects. We evaluated [Ca2+]i regulation, sarco/endoplasmic reticulum Ca2+- binding proteins, and phosphorylation levels of the ryanodine receptor in isolated rat myocytes. Electrical field-induced intracellular Ca2+ transients and contractions were recorded simultaneously. Myocytes superfused with 3-morpholinosydnonimine N-ethylcarbamide (SIN-1), an ONOO- donor, decreased the amplitude of Ca2+ transients and contraction in a dose-response (1-200 μM) manner. Similarly, SIN-1 increased half-time decay in a concentration-dependent manner. Co-infusion of the ONOO- donor with FeTMPyP (1 μM), an ONOO- decomposition catalyst, inhibited the effects induced by ONOO-. Impaired sarcoplasmic reticulum Ca2+ uptake caused by ONOO- (SIN-1 200 μM) was confirmed by a reduction of caffeine-evoked Ca2+ release along with prolongation of the half-time decay. Surprisingly, ONOO- induced a spontaneous Ca2+ transient that started at the beginning of the relaxation phase and was inhibited by tetracaine. Also, reduced phosphorylation at the ryanodine receptor 2 (RyR2)-Ser-2814 site was observed. In conclusion, deficient sarco/endoplasmic reticulum Ca2+-ATPase-mediated Ca2+ uptake concomitant with augmented Ca2+ release by RyR2 in myocytes may be associated with modification of myocyte Ca2+ handling by ONOO-. Thus, development of cardiac failure in diabetes, nephropathy, or hypertension may be related with elevated ONOO- in cardiac tissue.

Pairing and Short-Range Correlations in Nuclear Systems

The structure and density dependence of the pairing gap in infinite matter is relevant for astrophysical phenomena and provides a starting point for the discussion of pairing properties in nuclear structure. Short-range correlations can significantly deplete the available single-particle strength around the Fermi surface and thus provide a reduction mechanism of the pairing gap. Here, we study this effect in the singlet and triplet channels of both neutron matter and symmetric nuclear matter. Our calculations use phase-shift equivalent interactions and chiral two-body and three-body interactions as a starting point. We find an unambiguous reduction of the gap in all channels with very small dependence on the NN force in the singlet neutron matter and the triplet nuclear matter channel. In the latter channel, SRC alone provide a 50% reduction of the pairing gap.

Incidence of respiratory viral infection in infants with respiratory symptoms evaluated for late-onset sepsis

OBJECTIVE

To determine the frequency, etiology and impact of respiratory viral infection (RVI) on infants evaluated for late-onset sepsis (LOS), defined as sepsis occurring >72 h of life, in the neonatal intensive care unit.

STUDY DESIGN

Prospective observational study conducted from 6 March 2014 to 3 May 2016 on infants evaluated for LOS. PCR viral panel performed on nasopharyngeal specimens among infants with clinical suspicion for RVI. Sequence analysis was performed to determine viral subtypes. Fisher's exact or χ² tests were done to determine the impact of RVI.

RESULTS

During the 26-month study, there were 357 blood cultures obtained for LOS evaluations, 29 (8%) had a respiratory virus detected. Only 88 (25%) of infants evaluated for LOS also had clinical suspicion for a respiratory viral infection. RSV (14 of 29; 48%) was the predominant virus detected. Almost all infants (13 of 14; 93%) with RSV required increased respiratory support. Antimicrobial therapy was withheld or discontinued on most infants with a virus detected (18 of 29; 62%) and in the majority where there was no confirmed bacterial co-infection (18 of 20; 90%).

CONCLUSION

The incidence of RVI in infants being evaluated for LOS is about 8%. RVI should be considered in LOS evaluation to prevent unnecessary antibiotic therapy.

Role of adenylyl cyclase in reduced β-adrenoceptor-mediated vasorelaxation during maturation

Beta-adrenergic receptor (βAR)-dependent blood vessel relaxation is impaired in older animals and G protein activation has been suggested as the causative mechanism. Here, we investigated the role of βAR subtypes (β1AR, β2AR, and β3AR) and cAMP in maturation-dependent vasorelaxation impairment. Aortic rings from 15 Sprague-Dawley male rats (3 or 9 weeks old) were harvested and left intact or denuded of the endothelium. Vascular relaxation in aortic rings from younger and older groups was compared in the presence of βAR subtype agonists and antagonists along with cAMP and cGMP antagonists. Isolated aortic rings were used to evaluate relaxation responses, protein expression was evaluated by western blot or real time PCR, and metabolites were measured by ELISA. Expression of βAR subtypes and adenylyl cyclase was assessed, and cAMP activity was measured in vascular tissue from both groups. Isoproterenol- and BRL744-dependent relaxation in aortic rings with and without endothelium from 9-week-old rats was impaired compared with younger rats. The β1AR antagonist CGP20712A (10^-7 M) did not affect isoproterenol or BRL744-dependent relaxation in arteries from either group. The β2AR antagonist ICI-118,551 (10^-7 M) inhibited isoproterenol-dependent aortic relaxation in both groups. The β3AR antagonist SR59230A (10^-7 M) inhibited isoproterenol- and BRL744-dependent aortic ring relaxation in younger but not in older rats. All βAR subtypes were expressed in both groups, although β3AR expression was lower in the older group. Adenylyl cyclase (SQ 22536) or protein kinase A (H89) inhibitors prevented isoproterenol-induced relaxation in younger but not in older rats. Production of cAMP was reduced in the older group. Adenylyl cyclase III and RyR3 protein expression was higher in the younger group. In conclusion, altered expression of β3AR and adenylyl cyclase III may be responsible for reduced cAMP production in the older group.

Organ Donation: What Are the Opinions of Nursing Students at the University of Bialystok in Poland?

BACKGROUND

Nursing students, as future professionals, have an enormous impact on the opinion of the rest of the population on topics of organ donation and transplantation (ODT). The objective of this study was to analyze the attitudes of nursing students at the University of Bialystok toward ODT, and to determine the factors that affect ithemt.

METHODS

Academic year 2011-2012.

STUDY POPULATION

nursing students at the University of Bialystok. Type of sampling: sampling points during 5 compulsory-attendance nursing courses with >80% fulfillment. Measuring instrument: validated questionnaire (PCID-ODT Rios) filled out anonymously and self-administered.

RESULTS

Completion rate of 90% (331/367): 58% (n = 191) in favor, 35% (n = 118) undecided, and 7% (n = 22) against. The most important variables were: being in the 1st year (odds ratio [OR], 4.444; 95% confidence interval [CI], 11.627-1.700; P = .002); not knowing any donor (OR, 12.048; 95% CI, 55.555-2.57; P = .018); being in favor of organ donation by a relative (OR, 6.25; 95% CI, 14.705-2.666; P < .001); discussing the topic with friends (OR, 2,785; 95% CI, 5.347-1.447; P = .002); not worried about the possible mutilation of the body after donation (OR, 3.039; 95% CI, 5.882-1.569; P = .001); favorable attitude toward ODT of mother (OR, 3.676 (0.881-1.814; P < .001); accepting other treatment options, such as inhumation (OR, 3.436; 95% CI, 7.092-1.655; P = .001); accepting autopsy after death (OR, 2.141; 95% CI, 4.065-1.126; P = .020); and professing the Catholic religion (OR, 3.436; 95% CI, 8.333-1.410; P = .007).

CONCLUSIONS

More than 42% of the nursing students were not in favor of organ donation, their attitudes influenced by various psychosocial factors.

Knowledge of the Concept of Encephalic Death: Is This an Obstacle in the Acceptance of Donation and Transplantation of Organs Among Students of Nursing at the Medical University of Warsaw in Poland?

BACKGROUND

The knowledge and acceptance of the concept of brain death among future health professionals is essential. The objective of this study was to analyze the knowledge of the concept of brain death among nursing students at the Medical University of Warsaw and determine the factors that affect it.

METHODS

Academic year 2011-2012, nursing students of the University of Poland. Sampling points in 5 compulsory-attendance nursing courses with a completion rate >80%. Validated questionnaire (PCID-DTO Rios), anonymous and self-administered.

RESULTS

The completion rate was 96% (793/828); 71% (n = 561) knew the concept of brain death, 22% (n = 178) did not know it, and 7% (n = 54) did not know that it implies the death of the patient. Variables related to the correct knowledge: 1) to be studying in 4th year compared with 1st year (85% vs 60%; P ≤ .001); 2) discuss the subject with family (76% vs 61%; P ≤ .001); 3) discuss with friends (73% vs 63%; P = .009); and 4) having a favorable attitude toward organ donation (74% vs 65%; P = .011). In the multivariate analysis, the variables that remained independent were studying in 4th year (odds ratio [OR], 3.809; 95% confidence interval [CI], 2.006-5.823; P ≤ .001) and discussed with family concerning donation and transplantation (OR, 1.718; 95% CI, 1.241-2.381; P ≤ .001).

CONCLUSIONS

One-third of the nursing students were unfamiliar with the concept of brain death.

Donate a Piece of Liver: Is This an Option Accepted by Future Nurses of Pomeranian Medical University in Poland?

BACKGROUND

Liver transplantation from living donors (LLD) has become a viable and important source of liver grafts. The objective of this study was to analyze the attitude of nursing students at the Pomeranian Medical University in Poland on donation of live liver, and to determine the factors that affect it.

METHODS

Academic year 2011-2012, nursing students at a university in Poland, sampling points in 5 compulsory-attendance nursing courses with a completion rate of 80%, validated questionnaire (PCID-DVH Rios) filled out anonymously and self-administered.

RESULTS

The completion rate was 89% (227/254). Of the 227 students surveyed, 92% (n = 209) were in favor, 6% (n = 14) undecided, and 2% (n = 4) against. When the LLD is not related, 44% (n = 100) of respondents would be in favor. With a positive attitude toward this type of donation, we associated the following variables: 1) age, with the youngest showing a more favorable attitude (P = .006); 2) attitude in favor of living kidney donation (98% vs 85%; odds ratio, 4.950; 95% confidence interval, 9.259-2.652; P = .002); 3) attitude in favor of accepting a family LLD (96% vs 81%; P = .003); 4) discussing donation and transplantation with family (95% vs 87%; P = .043).

CONCLUSIONS

Ninety-two percent of nursing students at the Pomeranian Medical University in Poland were in favor of live organ donation, an attitude conditioned by various psychosocial factors.

Opinion of Nursing Students of the University of Bydgoszcz in Poland About the Transplantation of Living Liver Donors

INTRODUCTION

Liver transplantation from living liver donation (LLD) has become an important source of liver grafts.

MATERIAL AND METHOD

We studied the 2011-2012 academic year attitude of nursing students from a university in Poland. The sampling points were compulsory attendance in the 5 nursing courses. The validated questionnaire was Project Collaborative International Donor-Living Liver Donation Rios. The questionnaire was completed anonymously and was self-administered.

RESULTS

The completion rate was 89% (440 of 495); 91% (n = 398) were in favor of the related LLD, 8% (n = 37) were undecided, and 1% (n = 5) were against. When the attitude toward LLD is not related, 40% (n = 177) of respondents were in favor. The favorable attitude was associated with the following: consideration of the needs of organs for transplantations are covered (P ≤ .001); attitude in favor toward organ donation and transplantation (ODT) (P = .001); attitude in favor toward LLD (P = .007); attitude in favor of the acceptance of a LLD by a family member (P = .001); discussion of ODT with the family (P ≤ .001); being in favor of donating organs of a relative (P ≤ .001); and being Catholic (P = .003). After multivariate analysis, we observed the following significant correlations: the thought that the needs of transplantation organs are covered (odds ratio [OR] = 4.608; P = .020); being ready to accept a liver from a LLD (OR = 3.125; P = .038); discussion with the family about the subject of donation and transplantation (OR = 3.215; P = .003); and not belonging to any doctrine or religious belief (OR = 11.363; P = .039).

CONCLUSIONS

In this study 91% of nursing students were in favor of living organ donation.

Complete and repeatable inactivation of HIV-1 viral particles in suspension using a photo-labeled non-nucleoside reverse transcriptase inhibitor

A method is described for achieving repeatable, complete inactivation of HIV, based on photo-inactivation of HIV reverse transcriptase (RT) with a non-nucleoside reverse transcriptase inhibitor (NNRTI), photoactive 4-[[4-[(4-azido-2,6-dimethylphenyl) amino]-2-pyrimidinyl]amino]benzonitrile (PA-DAPYa). These results show that PA-DAPYa inactivated completely a suspension of cell-free HIV-1 viral particles in a dose and time-dependent manner. Using an ELISA assay for p24, it is demonstrated that a 500nM concentration of PA-DAPYa is able to inactivate 500 TCID50 of HIV viral particles in suspension when irradiated with non-microbicidal wavelength UV light for 30min. No active p24 was detected on days 7, 14, and 21 days after culturing the inactivated HIV in peripheral blood mononuclear cells (PBMCs). Several batches of large quantities of HIV viral particles were demonstrated to be inactivated completely and repeatedly by this method. Therefore, a reliable method has been developed to inactivate HIV viral particles in a reproducible manner using an optimal concentration of PA-DAPYa and duration of UV exposure time of the treated particles. The inactivation of viral particles in suspension allows for large-scale production of an injectable formulation of inactivated HIV viral particles for vaccine development which should preserve the conformational and antigenic integrity of viral surface proteins.

Charge radius isotope shift across the N=126 shell gap

We revisit the problem of the kink in the charge radius shift of neutron-rich even isotopes near the N=126 shell closure. We show that the ability of a Skyrme force to reproduce the isotope shift is determined by the occupation of the neutron 1i(11/2) orbital beyond N=126 and the corresponding change it causes to deeply-bound protons orbitals with a principal quantum number of 1. Given the observed position of the single-particle energies, one must either ensure occupation is allowed through correlations, or not demand that the single-particle energies agree with experimental values at the mean-field level.

Pesticide residue levels in green beans cultivated in Souss Masa valley (Morocco) after multiple applications of bifenthrin and λ-cyhalothrin

Dissipation of bifenthrin and λ-cyhalothrin pyrethroid insecticides, under environmental conditions, was evaluated on green beans grown in experimental greenhouses (Souss Massa valley, Morocco). Pesticide residues were determined by gas chromatography with micro electron-capture detector (GC-μECD) after dichloromethane extraction and cleanup on florisil phase cartridges. In the case of field experiments, a random block scheme was employed. Each block contained 25 plants in a single row and tests were carried out in triplicates applying pesticides at the recommended doses by the manufacturers. Fruit samples were periodically taken until the end of the preharvest interval (p.i.). The results obtained showed that the p.i of bifenthrin in green bean were 4 days in the winter and 3.5 days in the spring, whereas that for λ-cyhalothrin 8 days was found in the winter and 7.5 days in the spring. Consequently, it is possible to consider the European Union maximum residue limit (EU MRL) values compatible with the proper agricultural practices used for growing green bean in the plastic greenhouse of Souss Massa valley in South Morocco. Bifenthrin had a degradation of first-order kinetics, whereas that of levels for λ-cyhalothrin residue can not be interpreted by the use of a first order model.