Short-range interactions in a two-electron system: energy levels and magnetic properties

The problem of two electrons in a square billiard interacting via a finite-range repulsive Yukawa potential and subjected to a constant magnetic field is considered. We compute the energy spectrum for both singlet and triplet states, and for all symmetry classes, as a function of the strength and range of the interaction and of the magnetic field. We show that the short-range nature of the potential suppresses the formation of ``Wigner molecule'' states for the ground state, even in the strong interaction limit. The magnetic susceptibility $\chi(B)$ shows low-temperature paramagnetic peaks due to exchange induced singlet-triplet oscillations. The position, number and intensity of these peaks depend on the range and strength of the interaction. The contribution of the interaction to the susceptibility displays paramagnetic and diamagnetic phases as a function of $T$.Comment: 12 pages,6 figures; to appear in Phys. Rev.

Effects of 2 or 5 consecutive exercise days on adipocyte area and lipid parameters in Wistar rats

<p>Abstract</p> <p>Background</p> <p>Exercise has been prescribed in the treatment and control of dyslipidemias and cholesterolemia, however, lipid responses to different training frequencies in hypercholesterolemic men have been inconsistent. We sought to verify if different frequencies of continuous moderate exercise (2 or 5 days/week, swimming) can, after 8 weeks, promote adaptations in adipocyte area and lipid parameters, as well as body weight and relative weight of tissues in normo and hypercholesterolemic adult male rats.</p> <p>Methods</p> <p>Normal cholesterol chow diet or cholesterol-rich diet (1% cholesterol plus 0.25% cholic acid) were freely given during 8 weeks to the rats divided in 6 experimentals groups: sedentary normal cholesterol chow diet (C); sedentary cholesterol-rich diet (H); 5× per week continuous training normal cholesterol chow diet (TC5) and cholesterol-rich diet (TH5); 2× per week continuos traning normal cholesterol chow diet (TC2) and cholesterol-rich diet (TH2).</p> <p>Results</p> <p>No changes were observed in lipid profile in normal cholesterol chow diet, but both 2 a 5 days/week exercise improved this profile in cholesterol-rich diet. Body weight gain was lower in exercised rats. Decrease in retroperitoneal and epididymal relative weights as well as reductions in adipocyte areas under all diets types were observed only in 5 days/week, while 2 days/week showed improvements mainly in cholesterol-rich diet rats.</p> <p>Conclusion</p> <p>Our results confirm the importance of exercise protocols to control dyslipidemias and obesity in rats. The effects of 5 days/week exercise were more pronounced compared with those of 2 consecutive days/week training.</p

The same storm but not the same boat: Effects of COVID ‐19 stay‐at‐home order on mental health in individuals with overweight

Objective: To describe the effects of stay‐at‐home orders and social distancing during the coronavirus disease (COVID‐19) outbreak on mental health and to compare these outcomes between individuals with normal weight and overweight. Methods: This cross‐sectional study included 1857 Brazilian adults, who were invited through social media to answer an online questionnaire from 5 May 2020 to 17 May 2020. The instrument included questions related to health behaviour, mental health (anxiety, depression, self‐esteem, sadness and stress) and overall health. Overweight was defined as body mass index (BMI) ≥ 25 Kg/m2. Multiple logistic regression was conducted to identify whether overweight is associated with mental health variables. Results: Women reported increased anxiety (36.5% vs 22.2%, P < .01), depression (16.2% vs 8.8%, P < .01), low self‐esteem (19.8% vs 10.6%, P < .01), sadness (17.7% vs 10.2%, P < .01), and stress (29.5% vs 19.3%, P < .01) relative to men. Women with overweight are more likely to report higher feeling of anxiety (OR 1.62, CI 95% 1.22‐2.14), depression (OR 1.79, CI 95% 1.25‐2.55), low self‐esteem (OR 1.82, CI95% 1.28‐2.58) and sadness (OR 1.51, CI 95% 1.08‐2.10), adjusted for age, social isolation days, educational level, chronic diseases, smoke, alcohol intake and physical activity. Conclusion: Women, specially those with overweight are more vulnerable to the deleterious effects of stay‐at‐home orders on mental health during the COVID‐19 pandemic

Physical Activity Is Associated With Improved Eating Habits During the COVID-19 Pandemic

The aim of this study was to analyze the association between physical activity andeating habits during the COVID-19 pandemic among Brazilian adults. A sample of1,929 participants answered an online survey, however 1,874 were included in theanalysis. The impact of the COVID-19 pandemic on eating habits was assessedinquiring about participants’ intake of fruits, vegetables, fried foods, and sweetsduring the pandemic. Physical activity was assessed by asking participants abouttheir weekly frequency, intensity and number of minutes/hours engaging in structuredphysical activities per week. Participants were then stratified into categories based onmoderate-to-vigorous intensity (0–30; 31–90; 91–150; 151–300; and >300 min/week)and into active (≥150 min) or inactive (<150 min). Increased sweets consumption wasthe most commonly reported change to eating habits (42.5%), followed by an increase inthe consumption of vegetables (26.6%), fruits (25.9%), and fried foods (17.9%). Physicalactivity practice was related to lower consumption of fried foods (OR = 0.60; p < 0.001)and sweets (OR = 0.53; p < 0.001). A cluster analysis revealed subjects with higherthe level of physical activity was more likely to follow a healthy diet (p < 0.001). Thus,physical activity was positively associated with healthier eating habits. Health authoritiesmust recommend regular physical as a strategy to improve overall health during theCOVID-19 pandemic. Future studies should address the physical activity interventionsto improve health status during a pandemic

Anticipation of guilt for everyday moral transgressions : the role of the anterior insula and the influence of interpersonal psychopathic traits

Psychopathy is a personality disorder characterised by atypical moral behaviour likely rooted in atypical affective/motivational processing, as opposed to an inability to judge the wrongness of an action. Guilt is a moral emotion believed to play a crucial role in adherence to moral and social norms, but the mechanisms by which guilt (or lack thereof) may influence behaviour in individuals with high levels of psychopathic traits are unclear. We measured neural responses during the anticipation of guilt about committing potential everyday moral transgressions, and tested the extent to which these varied with psychopathic traits. We found a significant interaction between the degree to which anticipated guilt was modulated in the anterior insula and interpersonal psychopathic traits: anterior insula modulation of anticipated guilt was weaker in individuals with higher levels of these traits. Data from a second sample confirmed that this pattern of findings was specific to the modulation of anticipated guilt and not related to the perceived wrongness of the transgression. These results suggest a central role for the anterior insula in coding the anticipation of guilt regarding potential moral transgressions and advance our understanding of the neurocognitive mechanisms that may underlie propensity to antisocial behaviour

Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV

We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure

Simultaneous measurement of the ratio B(t->Wb)/B(t->Wq) and the top quark pair production cross section with the D0 detector at sqrt(s)=1.96 TeV

We present the first simultaneous measurement of the ratio of branching fractions, R=B(t->Wb)/B(t->Wq), with q being a d, s, or b quark, and the top quark pair production cross section sigma_ttbar in the lepton plus jets channel using 0.9 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV collected with the D0 detector. We extract R and sigma_ttbar by analyzing samples of events with 0, 1 and >= 2 identified b jets. We measure R = 0.97 +0.09-0.08 (stat+syst) and sigma_ttbar = 8.18 +0.90-0.84 (stat+syst)} +/-0.50 (lumi) pb, in agreement with the standard model prediction.Comment: submitted to Phys.Rev.Letter

Search for anomalous \boldmath{Wtb} couplings in single top quark production

In 0.9 fb$^{-1}$ of $p \bar p$ collisions, D0 has observed an excess of events with an isolated lepton, missing transve rse momentum, and two to four jets. This excess is consistent with single top quark production. We examine these data to study the Lorentz structure of the $Wtb$ coupling. The standard model predicts a left-handed vector coupling at the $Wt b$ vertex. The most general lowest dimension, CP-conserving Lagrangian admits right-handed vector and left- or right-h anded tensor couplings as well. We find that the data prefer the left-handed vector coupling and set upper limits on the anomalous couplings. These are the first direct constraints on a general $Wtb$ interaction and the first direct limits on left- and right-handed tensor couplings.Comment: 7 pages, 4 figure

Search for charged Higgs bosons decaying to top and bottom quarks in ppbar collisions

We describe a search for production of a charged Higgs boson, q \bar{q'} -> H^+, reconstructed in the t\bar{b} final state in the mass range 180 <= M_{H^+} <= 300 GeV. The search was undertaken at the Fermilab Tevatron collider with a center-of-mass energy sqrt{s} = 1.96 TeV and uses 0.9 fb^{-1} of data collected with the D0 detector. We find no evidence for charged Higgs boson production and set upper limits on the production cross section in the Types I, II and III two-Higgs-doublet models (2HDMs). An excluded region in the (M_{H^+},tan\beta) plane for Type I 2HDM is presented.Comment: Submitted to Phys. Rev. Letter