Interaction potential between dynamic dipoles: polarized excitons in strong magnetic fields

The interaction potential of a two-dimensional system of excitons with spatially separated electron-hole layers is considered in the strong magnetic field limit. The excitons are assumed to have free dynamics in the $x$-$y$ plane, while being constrained or `polarized' in the $z$ direction. The model simulates semiconductor double layer systems under strong magnetic field normal to the layers. The {\em residual} interaction between excitons exhibits interesting features, arising from the coupling of the center-of-mass and internal degrees of freedom of the exciton in the magnetic field. This coupling induces a dynamical dipole moment proportional to the center-of-mass magnetic moment of the exciton. We show the explicit dependence of the inter-exciton potential matrix elements, and discuss the underlying physics. The unusual features of the interaction potential would be reflected in the collective response and non-equilibrium properties of such system.Comment: REVTEX - 11 pages - 1 fi

Presencia y resistencia a antimicrobianos de Escherichia coli aislados a partir de alimentos en el estado de Hidalgo (México)

The presence of Escherichia coli in foods taken from the grocery stores and the supermarkets in Hidalgo State (Mexico) was determined for 73 samples of poultry meat, 60 samples of pork, 86 samples of beef, and 66 samples of vegetables. A total of 352 E. coli strains were isolated, identified, and analyzed by an agar disk diffusion assay for their resistance to 10 antimicrobials. Poultry meat and vegetables taken from groceries showed significantly higher counts (P = 0.0002 and P = 0.0461, respectively) when compared with the samples taken from supermarkets. Compared with the isolates recovered from other foods, E. coli isolated from chicken meat had higher levels of antimicrobial resistance against all antimicrobials tested, with the exceptions of nitrofurantoin resistance of isolates from pork and streptomycin resistance in isolates from pork and beef. In addition, the E. coli isolates from samples taken from the groceries showed higher resistance rates than the isolates from samples taken from the supermarkets for the cases of pork isolates resistance to ampicillin (P = 0.0497), chloramphenicol (P = 0.0075), doxycycline (P = 0.002), and streptomycin (P = 0.0094) and beef isolates resistance against ampicillin (P = 0.0048), streptomycin (P = 0.002), and sulfisoxazole (P = 0.003). The present study revealed that the observed resistance rates correlated well with those reported in the national surveillance programmes of developed countries, with the exception of isolates from chicken meat, which have higher resistance rates. Also, from a microbiological safety point of view, samples taken from supermarkets were in a much better conditions than those obtained from the groceriesLa presencia de Escherichia coli fue investigada en 73 muestras de carne de pollo, 60 muestras de carne de cerdo, 86 muestras de carne de vacuno y 66 muestras de alimentos vegetales muestreados en pequeños ultramarinos y supermercados en el estado de Hidalgo (México). Un total de 352 aislamientos de E. coli fueron seleccionados, identificados y analizados mediante el método de difusión en disco para determinar su resistencia a 10 antimicrobianos. Las muestras de pollo y vegetales obtenidas en tiendas de alimentación mostraron recuentos de E. coli significativamente mayores (P = 0,0002 y P = 0,0461 respectivamente) que las obtenidas en supermercados. Comparados con los procedentes de los restantes alimentos, los E. coli obtenidos a partir de carne de pollo mostraron un mayor grado de resistencia a todos los antimicrobianos estudiados, excepto en lo referente a la nitrofurantoína en el caso de los aislados a partir de carne de cerdo y la estreptomicina respecto de los aislamientos de carne de cerdo y vacuno. Adicionalmente, en algunos casos, los E. coli obtenidos a partir de alimentos muestreados en pequeños ultramarinos mostraron mayores tasas de resistencia que los procedentes de alimentos muestreados en supermercados. Esto ocurrió en los aislamientos procedentes de carne de cerdo para la ampicilina (P = 0,0497), cloranfenicol (P = 0,0075), doxiciclina (P = 0,002) y estreptomicina (P = 0,0094), y en el caso de la carne de vacuno para la ampicilina (P = 0,0048), estreptomicina (P = 0,002) y sulfizoxazol (P = 0,003). El presente estudio demuestra que las tasas de resistencia observadas son compatibles con las publicadas en los programas nacionales de vigilancia de los países desarrollados, con la excepción de los aislamientos procedentes de carne de pollo, en los cuales las tasas de resistencia tienden a ser mayores. Además, desde el punto de vista de la seguridad microbiológica, las muestras obtenidas en supermercados mostraron condiciones significativamente mejores que las obtenidas en tiendas de alimentaciónThe authors are thankful for financial support from Dirección Xeral de Investigación, Desenvolvemento e Innovación (Xunta de Galicia) (grant IN843A2007/42), and CONACYT (Project CB-2006–61310)S

Prevention of diet-induced obesity by apple polyphenols in Wistar rats through regulation of adipocyte gene expression and DNA methylation patterns

This study was conducted to determine the mechanisms implicated in the beneficial effects of apple polyphenols (APs) against diet-induced obesity in Wistar rats, described in a previous study from our group. Supplementation of high-fat sucrose diet with AP prevented adiposity increase by inhibition of adipocyte hypertrophy. Rats supplemented with AP exhibited improved glucose tolerance while adipocytes isolated from these rats showed an enhanced lipolytic response to isoproterenol. AP intake led to reduced Lep, Plin, and sterol regulatory element binding transcription factor 1 (Srebf1) mRNA levels and increased aquaporin 7 (Aqp7), adipocyte enhancer binding protein 1 (Aebp1), and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (Ppargc1a) mRNA levels in epididymal adipocytes. In addition, we found different methylation patterns of Aqp7, Lep, Ppargc1a, and Srebf1 promoters in adipocytes from apple-supplemented rats compared to high-fat sucrose fed rats. The administration of AP protects against body weight gain and fat deposition and improves glucose tolerance in rats. We propose that AP exerts the antiobesity effects through the regulation of genes involved in adipogenesis, lipolysis, and fatty acid oxidation, in a process that could be mediated in part by epigenetic mechanisms

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Surgical treatment for colorectal cancer: Analysis of the influence of an enhanced recovery programme on long-term oncological outcomes-a study protocol for a prospective, multicentre, observational cohort study

Introduction The evidence currently available from enhanced recovery after surgery (ERAS) programmes concerns their benefits in the immediate postoperative period, but there is still very little evidence as to whether their correct implementation benefits patients in the long term. The working hypothesis here is that, due to the lower response to surgical aggression and lower rates of postoperative complications, ERAS protocols can reduce colorectal cancer-related mortality. The main objective of this study is to analyse the impact of an ERAS programme for colorectal cancer on 5-year survival. As secondary objectives, we propose to analyse the weight of each of the predefined items in the oncological results as well as the quality of life. Methods and analysis A multicentre prospective cohort study was conducted in patients older than 18 years of age who are scheduled to undergo surgery for colorectal cancer. The study involved 12 hospitals with an implemented enhanced recovery protocol according to the guidelines published by the Spanish National Health Service. The intervention group includes patients with a minimum implementation level of 70%, and the control group includes those who fail to reach this level. Compliance will be studied using 18 key performance indicators, and the results will be analysed using cancer survival indicators, including overall survival, cancer-specific survival and relapse-free survival. The time to recurrence, perioperative morbidity and mortality, hospital stay and quality of life will also be studied, the latter using the validated EuroQol Five questionnaire. The propensity index method will be used to create comparable treatment and control groups, and a multivariate regression will be used to study each variable. The Kaplan-Meier estimator will be used to estimate survival and the log-rank test to make comparisons. A p value of less than 0.05 (two-tailed) will be considered to be significant. Ethics and dissemination Ethical approval for this study was obtained from the Aragon Ethical Committee (C.P.-C.I. PI20/086) on 4 March 2020. The findings of this study will be submitted to peer-reviewed journals (BMJ Open, JAMA Surgery, Annals of Surgery, British Journal of Surgery). Abstracts will be submitted to relevant national and international meetings. Trial registration number NCT04305314

The global burden of falls: Global, regional and national estimates of morbidity and mortality from the Global Burden of Disease Study 2017

Background: Falls can lead to severe health loss including death. Past research has shown that falls are an important cause of death and disability worldwide. The Global Burden of Disease Study 2017 (GBD 2017) provides a comprehensive assessment of morbidity and mortality from falls. Methods: Estimates for mortality, years of life lost (YLLs), incidence, prevalence, years lived with disability (YLDs) and disability-adjusted life years (DALYs) were produced for 195 countries and territories from 1990 to 2017 for all ages using the GBD 2017 framework. Distributions of the bodily injury (eg, hip fracture) were estimated using hospital records. Results: Globally, the age-standardised incidence of falls was 2238 (1990-2532) per 100 000 in 2017, representing a decline of 3.7% (7.4 to 0.3) from 1990 to 2017. Age-standardised prevalence w

Overview of recent TJ-II stellarator results

The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presented. ISSN:0029-5515 ISSN:1741-432