Static and resonant properties of decorated square kagome lattice compound KCu7_7(TeO4_4)(SO4_4)5_5Cl

The magnetic subsystem of nabokoite, KCu$_7$(TeO$_4$)(SO$_4$)$_5$Cl, is constituted by buckled square kagome lattice of copper decorated by quasi-isolated Cu$^{2+}$ ions. This combination determines peculiar physical properties of this compound evidenced in electron spin resonance (ESR) spectroscopy, dielectric permittivity $\varepsilon$, magnetization $M$ and specific heat $C_p$ measurements. At lowering temperature, the magnetic susceptibility $\chi = M/H$ passes through broad hump at about 150 K inherent for low-dimensional magnetic systems and evidences sharp peak at antiferromagnetic phase transition at $T_N = 3.2$K. The $C_p(T)$ curve also exhibits sharp peak at $T_N$ readily suppressed by magnetic field and additional peak-like anomaly at $T_\textrm{peak}= 5.7$ K robust to magnetic field. The latter can be ascribed to low-lying singlet excitations filling the singlet-triplet gap in magnetic excitation spectrum of the square kagome lattice [J.Richter, O.Derzhko and J.Schnack, Phys. Rev. B 105, 144427 (2022)]. According to position of $T_\textrm{peak}$, the leading exchange interaction parameter $J$ in nabokoite is estimated to be about 60K. ESR spectroscopy provides indications that antiferromagnetic structure below $T_N$ is non-collinear. These complex thermodynamic and resonant properties signal the presence of two weakly coupled magnetic subsystems in nabokoite, namely spin-liquid with large singlet-triplet gap and antiferromagnet represented by decorating ions. Separate issue is the observation of antiferroelectric-type behavior in $\varepsilon$ at low temperatures, which tentatively reduces the symmetry and partially lifts frustration of magnetic interactions of decorating copper ions with buckled square kagome lattice.Comment: 13 pages, 13 figure

Quasi-1D XY Antiferromagnet Sr2Ni(SeO3)2Cl2 at Sakai-Takahashi Phase Diagram

Uniform quasi-one-dimensional integer spin compounds are of interest as a potential realization of the Haldane conjecture of a gapped spin liquid. This phase, however, has to compete with magnetic anisotropy and long-range ordered phases, the implementation of which depends on the ratio of interchain J′ and intrachain J exchange interactions and both uniaxial D and rhombic E single-ion anisotropies. Strontium nickel selenite chloride, Sr2Ni(SeO3)2Cl2, is a spin-1 chain system which passes through a correlations regime at Tmax ~ 12 K to long-range order at TN = 6 K. under external magnetic field it experiences the sequence of spin-flop at Bc1 = 9.0 T and spin-flip transitions Bc2 = 23.7 T prior to full saturation at Bsat = 31.0 T. Density functional theory provides values of the main exchange interactions and uniaxial anisotropy which corroborate the experimental findings. The values of J′/J = 0.083 and D/J = 0.357 place this compound into a hitherto unoccupied sector of the Sakai-Takahashi phase diagram. © 2021, The Author(s).Support by the P220 program of Government of Russia through the project 075-15-2021-604 is acknowledged. ANV acknowledges support by the RFBR Grant 19-02-00015. Work at Heidelberg was supported by BMBF via the project SpinFun (13XP5088) and by Deutsche Forschungsgemeinschaft (DFG) under Germany’s Excellence Strategy EXC2181/1-390900948 (the Heidelberg STRUCTURES Excellence Cluster) and through project KL 1824/13-1. We acknowledge the support of the HLD-HZDR, member of the European Magnetic Field Laboratory (EMFL). Theoretical calculations using density functional theory were supported by the Russian Science Foundation via project 20-62-46047. Experimental research was supported by the Russian Science Foundation via project 19-42-02010

Collective Phase-like Mode and the Role of Lattice Distortions at TN~TC in RMn2O5 (R= Pr, Sm, Gd, Tb, Bi)

We report on electronic collective excitations in RMn2O5 (R= Pr, Sm, Gd, Tb) showing condensation starting at and below TN\simTC\sim40-50 K. Its origin is understood as partial delocalized eg electron orbitals in the Jahn-Teller distortion of the pyramids dimmer with strong hybridized Mn3+-O bonds. Our local probes, Raman, infrared, and X-ray absorption, back the conclusion by which there is no structural phase transition at TN\simTC. Ferroelectricity is magnetically assisted by electron localization triggering lattice polarizability by unscreening. We have also found phonon hardening as the rare earth is sequentially replaced. This is understood as consequence of lanthanide contraction. It is suggested that partially f-electron screened Rare Earth nuclei might be introducing a perturbation to eg electrons prone to delocalize as the superexchange interaction takes place.Comment: Journal of Physics Cond. Matter April 12, 2012. In pres

Динамика маркеров повреждения миокарда в периоперационном периоде коронарного шунтирования в зависимости от программы преабилитации

Aim. To evaluate the morphological and functional cardiac parameters and to measure markers of myocardial injury in the perioperative period of patients undergoing coronary artery bypass grafting (CABG), depending on the prehabilitation program.Methods. 60 male patients with stable coronary artery disease (CAD) underwent screening in the preoperative period and were randomized into two groups. Group 1 (n = 30) underwent supervised treadmill exercises at intensity corresponding to 80% of VO2 peak during the preoperative management. Group 2 (n = 30) patients did not undergo any additional trainings. Patients underwent a standard echocardiographic (ECHO-CG) study in the preoperative period and at days 5-7 after CABG. Serum markers of myocardial injury (troponin I, NT-proBNP) were measured in both groups of patients in the preoperative period before training (measurement 1), at the end of exercise training sessions (measurement 2) and at days 5-7 (measurement 3) after CABG.Results. ECHO-CG findings reported that left ventricular end-systolic dimension (p = 0.039) and left ventricular end-systolic volume (p = 0.039) increased by 8.5% and 18% in patients who underwent supervised exercise trainings as compared to the baseline values. An increase in these parameters was more pronounced in the control group (17% (p = 0.00029) and 41% (p = 0.00028), respectively). NT-proBNP levels showed a downward trend in patients with prehabilitation at the end of the training sessions, while in the control group NT-proBNP levels increased. An increase in NT-proBNP levels was reliable in patients without exercise trainings (p = 0.003) after CABG compared to the preoperative values, while NT-proBNP levels did not differ significantly in patients who underwent prehabilitation (p>0.05).Conclusion. The safety of high-intensity exercise trainings in the prehabilitation program for CABG had been confirmed by laboratory markers of myocardial damage. The obtained data proved the efficiency of active prehabilitation for optimizing echocardiographic parameters and inducing cardioprotection.Цель. Оценить динамику морфофункциональных параметров и маркеров повреждения миокарда в периоперационном периоде коронарного шунтирования (КШ) в зависимости от выбранной программы преабилитации.Материалы и методы               . 60 пациентов мужского пола со стабильной ишемической болезнью сердца (ИБС) перед выполнением КШ в условиях искусственного кровообращения (ИК) после оценки критериев включения и исключения были рандомизированы на две группы: в группе 1 (n = 30) на фоне стандартной предоперационной подготовки был проведен курс тренировок на тредмиле, интенсивностью 80% от пикового потребления кислорода; в группе 2 (n = 30) тренировки не проводились. Оценка параметров эхокардиографии (ЭхоКГ) выполнялась в предоперационном периоде и на 5-7 сутки после КШ. Количественная оценка концентрации и динамики маркеров повреждения миокарда (тропонин I, NT-proBNP) в сыворотке крови выполнялась в предоперационном периоде до начала тренировок (1-я точка), после окончания курса (2-я точка) и в послеоперационном периоде на 5-7 сутки (3-я точка) пациентам обеих групп.Результаты. Анализ динамики параметров ЭхоКГ показал, что в группе пациентов с включением тренировок в программу преабилитации после операции увеличились показатели конечного систолического размера (КСР ЛЖ) (р = 0,039) и конечного систолического объема левого желудочка (КСО ЛЖ) (р = 0,039) по сравнению с дооперационными на 8,5% и 18% соответственно, при этом в группе контроля увеличение этих показателей оказалось более выраженным: на 17% (р = 0,00029) и 41% (р = 0,00028) соответственно. Оценка концентрации NT-proBNP показала тенденцию к снижению данного маркера у пациентов с преабилитацией после окончания курса тренировок, в то время как в группе контроля отмечалось его повышение. В послеоперационном периоде КШ отмечена значимая динамика нарастания концентрации NT-proBNP у пациентов без использования физических тренировок (р = 0,003) по сравнению с дооперационной, в то время как в группе с тренировками эта динамика оказалась статистически незначимой (р>0,05).Заключение. Продемонстрирована безопасность включения физических тренировок высокой интенсивности в программу преабилитации при КШ, подтвержденная динамикой лабораторных маркеров повреждения миокарда. Полученные данные свидетельствуют в пользу активной преабилитации с позиции оптимизации эхокардиографических параметров, а также возможной активации механизмов кардиопротекции на фоне выполнения физических тренировок

The severity of pandemic H1N1 influenza in the United States, from April to July 2009: A Bayesian analysis

Background: Accurate measures of the severity of pandemic (H1N1) 2009 influenza (pH1N1) are needed to assess the likely impact of an anticipated resurgence in the autumn in the Northern Hemisphere. Severity has been difficult to measure because jurisdictions with large numbers of deaths and other severe outcomes have had too many cases to assess the total number with confidence. Also, detection of severe cases may be more likely, resulting in overestimation of the severity of an average case. We sought to estimate the probabilities that symptomatic infection would lead to hospitalization, ICU admission, and death by combining data from multiple sources. Methods and Findings: We used complementary data from two US cities: Milwaukee attempted to identify cases of medically attended infection whether or not they required hospitalization, while New York City focused on the identification of hospitalizations, intensive care admission or mechanical ventilation (hereafter, ICU), and deaths. New York data were used to estimate numerators for ICU and death, and two sources of data - medically attended cases in Milwaukee or self-reported influenza-like illness (ILI) in New York - were used to estimate ratios of symptomatic cases to hospitalizations. Combining these data with estimates of the fraction detected for each level of severity, we estimated the proportion of symptomatic patients who died (symptomatic case-fatality ratio, sCFR), required ICU (sCIR), and required hospitalization (sCHR), overall and by age category. Evidence, prior information, and associated uncertainty were analyzed in a Bayesian evidence synthesis framework. Using medically attended cases and estimates of the proportion of symptomatic cases medically attended, we estimated an sCFR of 0.048% (95% credible interval [CI] 0.026%-0.096%), sCIR of 0.239% (0.134%-0.458%), and sCHR of 1.44% (0.83%-2.64%). Using self-reported ILI, we obtained estimates approximately 7-96lower. sCFR and sCIR appear to be highest in persons aged 18 y and older, and lowest in children aged 5-17 y. sCHR appears to be lowest in persons aged 5-17; our data were too sparse to allow us to determine the group in which it was the highest. Conclusions: These estimates suggest that an autumn-winter pandemic wave of pH1N1 with comparable severity per case could lead to a number of deaths in the range from considerably below that associated with seasonal influenza to slightly higher, but with the greatest impact in children aged 0-4 and adults 18-64. These estimates of impact depend on assumptions about total incidence of infection and would be larger if incidence of symptomatic infection were higher or shifted toward adults, if viral virulence increased, or if suboptimal treatment resulted from stress on the health care system; numbers would decrease if the total proportion of the population symptomatically infected were lower than assumed.published_or_final_versio

Species Tree Estimation for the Late Blight Pathogen, Phytophthora infestans, and Close Relatives

To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based “supergene” approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred

The Assortment Packing Problem: Multiperiod Assortment Planning for Short-Lived Products

Motivated by retailers ’ frequent introduction of new items to refresh product lines and maintain their market shares, we present the assortment packing problem in which a firm must decide, in advance, the release date of each product in a given collection over a selling season. Our formulation models the trade-offs among profit margins, preference weights, and limited life cycles. A key aspect of the problem is that each product is short-lived in the sense that, once introduced, its attractiveness lasts only a few periods and vanishes over time. The objective is to determine when to introduce each product to maximize the total profit over the selling season. Even for two periods, the corresponding optimization problem is shown to be NP-complete. As a result, we study a continuous relaxation of the problem that approximates the problem well, when the number of products is large. When margins are identical and product preferences decay exponentially, its solution can be characterized: it is optimal to introduce products with slower decays earlier. The structural properties of the relaxation also help us to develop several heuristics, for which we establish performance guarantees. We test our heuristics with data on sales and release dates of woman handbags from an accessories retailer. The numerical experiments show that the heuristics perform very well and can yield significant improvements in profitability. 1

Gamma radiations from a rough infinite plane /

"Technical Objective AW-5c.""Physics.""18 January 1956.""NS 083-001.""Research and Development Technical Report."Includes bibliographical references (page 7).Mode of access: Internet