433 research outputs found

    ^{59}Co NMR evidence for charge ordering below T_{CO}\sim 51 K in Na_{0.5}CoO_2

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    The CoO2_{2} layers in sodium-cobaltates Nax_{x}CoO2_{2} may be viewed as a spin S=1/2S=1/2 triangular-lattice doped with charge carriers. The underlying physics of the cobaltates is very similar to that of the high TcT_{c} cuprates. We will present unequivocal 59^{59}Co NMR evidence that below TCO∼51KT_{CO}\sim51 K, the insulating ground state of the itinerant antiferromagnet Na0.5_{0.5}CoO2_{2} (TN∼86KT_{N}\sim 86 K) is induced by charge ordering.Comment: Phys. Rev. Lett. 100 (2008), in press. 4 figure

    The Impact of the Coronavirus Lockdown on Mental Health: Evidence from the US

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    The coronavirus outbreak has caused significant disruptions to people’s lives. We exploit variation in lockdown measures across states to document the impact of stay-at-home orders on mental health using real time survey data in the US. We find that the lockdown measures lowered mental health by 0.083 standard deviations. This large negative effect is entirely driven by women. As a result of the lockdown measures, the existing gender gap in mental health has increased by 61%. The negative effect on women’s mental health cannot be explained by an increase in financial worries or caring responsibilities

    Perceived returns to job search

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    This paper provides new evidence on workers’ perceptions of the returns to job search effort using hypothetical vignettes. This allows us to overcome limitations with survey data on realized behavior in which search effort and reservation wages may be endogenous to perceived job finding rates. The perceived job finding probability is nearly linear in hours searched and only slightly concave for most respondents. While workers are over-optimistic about the probability of receiving a job offer conditional on any search, they perceive the marginal return to additional search hours as positive but comparably low. Job seekers receiving an offer, update their perceived returns upwards, while the beliefs of unsuccessful searchers regress towards the direction of the mean. We find little evidence that novel aspects of the pandemic recession have fundamentally changed workers’ motivations for job search: that an existing job is expected to end or has unsatisfactory pay are the primary motives for on-the-job search. On the contrary, workers’ ability to do their tasks from home is not a strong predictor of job search nor a significant motive for switching occupations

    Inequality in the Impact of the Coronavirus Shock: Evidence from Real Time Surveys

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    We present real time survey evidence from the UK, US and Germany showing that the labor market impacts of COVID-19 differ considerably across countries. Employees in Germany, which has a well-established short-time work scheme, are substantially less likely to be affected by the crisis. Within countries, the impacts are highly unequal and exacerbate existing inequalities. Workers in alternative work arrangements and in occupations in which only a small share of tasks can be done from home are more likely to have reduced their hours, lost their jobs and suffered falls in earnings. Less educated workers and women are more affected by the crisis

    Furloughing

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    Over 9 million jobs were furloughed in the UK during the Coronavirus pandemic. Using real time survey evidence from the UK in April and May, we document which workers were most likely to be furloughed and analyze variation in the terms on which they furl

    Geometric phases and anholonomy for a class of chaotic classical systems

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    Berry's phase may be viewed as arising from the parallel transport of a quantal state around a loop in parameter space. In this Letter, the classical limit of this transport is obtained for a particular class of chaotic systems. It is shown that this ``classical parallel transport'' is anholonomic --- transport around a closed curve in parameter space does not bring a point in phase space back to itself --- and is intimately related to the Robbins-Berry classical two-form.Comment: Revtex, 11 pages, no figures

    Fatty acid nitroalkenes ameliorate glucose intolerance and pulmonary hypertension in high-fat diet-induced obesity

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    Aims Obesity is a risk factor for diabetes and cardiovascular diseases, with the incidence of these disorders becoming epidemic. Pathogenic responses to obesity have been ascribed to adipose tissue (AT) dysfunction that promotes bioactive mediator secretion from visceral AT and the initiation of pro-inflammatory events that induce oxidative stress and tissue dysfunction. Current understanding supports that suppressing pro-inflammatory and oxidative events promotes improved metabolic and cardiovascular function. In this regard, electrophilic nitro-fatty acids display pleiotropic anti-inflammatory signalling actions. Methods and results It was hypothesized that high-fat diet (HFD)-induced inflammatory and metabolic responses, manifested by loss of glucose tolerance and vascular dysfunction, would be attenuated by systemic administration of nitrooctadecenoic acid (OA-NO2). Male C57BL/6j mice subjected to a HFD for 20 weeks displayed increased adiposity, fasting glucose, and insulin levels, which led to glucose intolerance and pulmonary hypertension, characterized by increased right ventricular (RV) end-systolic pressure (RVESP) and pulmonary vascular resistance (PVR). This was associated with increased lung xanthine oxidoreductase (XO) activity, macrophage infiltration, and enhanced expression of pro-inflammatory cytokines. Left ventricular (LV) end-diastolic pressure remained unaltered, indicating that the HFD produces pulmonary vascular remodelling, rather than LV dysfunction and pulmonary venous hypertension. Administration of OA-NO2 for the final 6.5 weeks of HFD improved glucose tolerance and significantly attenuated HFD-induced RVESP, PVR, RV hypertrophy, lung XO activity, oxidative stress, and pro-inflammatory pulmonary cytokine levels. Conclusions These observations support that the pleiotropic signalling actions of electrophilic fatty acids represent a therapeutic strategy for limiting the complex pathogenic responses instigated by obesity.Fil: Kelley, Eric E.. University of Pittsburgh; Estados UnidosFil: Baust, Jeff. University of Pittsburgh; Estados UnidosFil: Bonacci, Gustavo Roberto. University of Pittsburgh; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Golin Bisello, Franca. University of Pittsburgh; Estados UnidosFil: Devlin, Jason E.. University of Pittsburgh; Estados UnidosFil: Croix, Claudette M. St.. University of Pittsburgh; Estados UnidosFil: Watkins, Simon C.. University of Pittsburgh; Estados UnidosFil: Gor, Sonia. University of Pittsburgh; Estados UnidosFil: Cantu Medellin, Nadiezhda. University of Pittsburgh; Estados UnidosFil: Weidert, Eric R.. University of Pittsburgh; Estados UnidosFil: Frisbee,Jefferson C.. University of Virginia; Estados UnidosFil: Gladwin, Mark T.. University of Pittsburgh; Estados UnidosFil: Champion, Hunter C.. University of Pittsburgh; Estados UnidosFil: Freeman, Bruce A.. University of Pittsburgh; Estados UnidosFil: Khoo, Nicholas K.H.. University of Pittsburgh; Estados Unido
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