3,176 research outputs found

    A simple one-dimensional model of heat conduction which obeys Fourier's law

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    We present the computer simulation results of a chain of hard point particles with alternating masses interacting on its extremes with two thermal baths at different temperatures. We found that the system obeys Fourier's law at the thermodynamic limit. This result is against the actual belief that one dimensional systems with momentum conservative dynamics and nonzero pressure have infinite thermal conductivity. It seems that thermal resistivity occurs in our system due to a cooperative behavior in which light particles tend to absorb much more energy than the heavier ones.Comment: 5 pages, 4 figures, to be published in PR

    Partners for Change: Community Residents and Agencies

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    Efforts to combine the knowledge and skills of community residents and diverse professionals to bring about community and service delivery change are becoming increasingly popular, yet difficult to achieve. This article details, from the perspective of community residents and agency and university staff, the challenges, strategies, and benefits in developing one community-agency collaborative which has successfully engaged community residents. The program is located in a low-income, culturally-diverse, densely populated urban area. Challenges faced by the partnership included recruiting residents, reducing logistical barriers to resident involvement, joining together residents and agency staff, and aligning community and agency goals. Successful strategies in overcoming these challenges included responding quickly to community concerns, developing more personal recruiting strategies, changing logistics to enhance resident participation, increasing program visibility in the community, creating shared goals and vision, and training. Observed benefits include community residents believe their participation has resulted in personal, agency and neighborhood improvements and increased cross-cultural understanding

    Dedicated versus mainstreaming approaches in local climate plans in Europe

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    Cities are gaining prominence committing to respond to the threat of climate change, e.g., by developing local climate plans or strategies. However, little is known regarding the approaches and processes of plan development and implementation, or the success and effectiveness of proposed measures. Mainstreaming is regarded as one approach associated with (implementation) success, but the extent of integration of local climate policies and plans in ongoing sectoral and/or development planning is unclear. This paper analyses 885 cities across the 28 European countries to create a first reference baseline on the degree of climate mainstreaming in local climate plans. This will help to compare the benefits of mainstreaming versus dedicated climate plans, looking at policy effectiveness and ultimately delivery of much needed climate change efforts at the city level. All core cities of the European Urban Audit sample were analyzed, and their local climate plans classified as dedicated or mainstreamed in other local policy initiatives. It was found that the degree of mainstreaming is low for mitigation (9% of reviewed cities; 12% of the identified plans) and somewhat higher for adaptation (10% of cities; 29% of plans). In particular horizontal mainstreaming is a major effort for local authorities; an effort that does not necessarily pay off in terms of success of action implementation. This study concludes that climate change issues in local municipalities are best tackled by either, developing a dedicated local climate plan in parallel to a mainstreamed plan or by subsequently developing first the dedicated and later a mainstreaming plan (joint or subsequent “dual track approach”). Cities that currently provide dedicated local climate plans (66% of cities for mitigation; 26% of cities for adaptation) may follow-up with a mainstreaming approach. This promises effective implementation of tangible climate actions as well as subsequent diffusion of climate issues into other local sector policies. The development of only broad sustainability or resilience strategies is seen as critical.We thank the many council representatives that supported the datacollection. Special thanks to Birgit Georgi who helped in setting up this large net work of researchers across the EU-28. We also thank the EU COST Action TU 0902 (ledbyRichardDawson) that established the core research network and the positive engagement and interaction of th emembers of this group. OH is Fellow of the Tyndall Centre for Climate Change Research and was funded by the UK EPSRC LC Transforms: Low Carbon Transitions of Fleet Operations in Metropolitan Sites Project (grant number EP/N010612/1). EKL was supported by the Ministry of Education, Youth and Sports, Czechia, within the National Sustainability Program I (NPU I) (grant number LO1415). DG ac-knowledges support by the Ministry of Education, University and Research (MIUR), Italy ("Departments of Excellence" grant L. 232/2016). HO was supported by the Ministry of Education and Research, Estonia (grantnumberIUT34-17). MO acknowledges funding from the Ministry of Economy and Competitiveness (MINECO), Spain (grant number IJCI-2016-28835). SS acknowledges that CENSE's research is partially funded by the Science Foundation, Portugal (grant number UID/AMB/04085/2019). The paper reflects only the views of the authors. The European Union, the European Environment Agency or other supporting bodies are not liable for any use that may be made of the information that is provided in this manuscript

    Demagnetization via Nucleation of the Nonequilibrium Metastable Phase in a Model of Disorder

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    We study both analytically and numerically metastability and nucleation in a two-dimensional nonequilibrium Ising ferromagnet. Canonical equilibrium is dynamically impeded by a weak random perturbation which models homogeneous disorder of undetermined source. We present a simple theoretical description, in perfect agreement with Monte Carlo simulations, assuming that the decay of the nonequilibrium metastable state is due, as in equilibrium, to the competition between the surface and the bulk. This suggests one to accept a nonequilibrium "free-energy" at a mesoscopic/cluster level, and it ensues a nonequilibrium "surface tension" with some peculiar low-T behavior. We illustrate the occurrence of intriguing nonequilibrium phenomena, including: (i) Noise-enhanced stabilization of nonequilibrium metastable states; (ii) reentrance of the limit of metastability under strong nonequilibrium conditions; and (iii) resonant propagation of domain walls. The cooperative behavior of our system may also be understood in terms of a Langevin equation with additive and multiplicative noises. We also studied metastability in the case of open boundaries as it may correspond to a magnetic nanoparticle. We then observe burst-like relaxation at low T, triggered by the additional surface randomness, with scale-free avalanches which closely resemble the type of relaxation reported for many complex systems. We show that this results from the superposition of many demagnetization events, each with a well- defined scale which is determined by the curvature of the domain wall at which it originates. This is an example of (apparent) scale invariance in a nonequilibrium setting which is not to be associated with any familiar kind of criticality.Comment: 26 pages, 22 figure

    Evaluación de la inmunogenicidad de una proteína recombinante de una Pasteurella multocida aislada de alpacas con neumonía

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    The aim of the study was to evaluate the in vitro immunogenic activity of a recombinant P6-like protein from a culture of Pasteurella multocida isolated from pneumonia cases in young alpacas. Blood peripheral mononuclear cells (PBMCs) were challenged with a recombinant P6-like protein at a concentration of 10 ng per sample, from 3 to 72 hours. Total RNA was extracted to perform the real-time RT-PCR test to observe cytokine expression levels of the Th1 immune response (TNF-α, IFN-γ and IL-2) and Th2 (IL-10 and IL-4) in the established times. Both Th1 and Th2 profile cytokines expressed a greater number of times than PBMC not exposed to the recombinant protein, where at 24 and 48 hours showed the greater expressions. Likewise, an apparent trend toward the Th2 profile was found, but at levels that did not influence the expression of cytokines in the other profile.El objetivo del estudio fue evaluar la actividad inmunogénica in vitro de una proteína P6-like recombinante procedente de un cultivo de Pasteurella multocida aislada de cuadros de neumonía en crías de alpacas. Se desafiaron cultivos de células mononucleares periféricas sanguíneas (PBMC) con una proteína recombinante P6-like a una concentración de 10 ng por muestra, desde las 3 hasta las 72 horas. Se extrajo ARN totales para realizar la prueba de RT-PCR en tiempo real para observar los niveles de expresión de citoquinas de la respuesta inmune Th1 (TNF-á, IFN-g e IL-2) y Th2 (IL-10 e IL-4) en los tiempos establecidos. Se encontró que tanto las citoquinas con perfil Th1 como Th2 expresan un mayor número de veces con respecto a PBMC no expuestos a la proteína recombinante, siendo las 24 y 48 horas los momentos de mayor expresión. Asimismo, se encontró una aparente tendencia hacia el perfil Th2, pero en niveles que no influyen en la expresión de citoquinas del otro perfil

    SDSS-IV MaNGA : the MaNGA dwarf galaxy sample presentation

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    M.C.D. acknowledges support from CONACYT "Ciencia de Frontera" grant 320199. M.C.D. and H.M.H.T. acknowledge support from UC MEXUS-CONACYT grant CN-17-128. A.R.P. acknowledges support from the CONACyT "Ciencia Basica" grant 285721. E.A.O. acknowledges support from the SECTEI (Secretaría de Educación, Ciencia, Tecnología e Innovación de la Ciudad de México) under the Postdoctoral Fellowship SECTEI/170/2021 and CM-SECTEI/303/2021. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions.We present the MaNGA Dwarf galaxy (MaNDala) Value Added Catalog (VAC), from the final release of the Sloan Digital Sky Survey-IV program. MaNDala consists of 136 randomly selected bright dwarf galaxies with M* −18.5, making it the largest integral field spectroscopy homogeneous sample of dwarf galaxies. We release a photometric analysis of the g, r, and z broadband imaging based on the DESI Legacy Imaging Surveys, as well as a spectroscopic analysis based on the Pipe3D SDSS-IV VAC. Our release includes the surface brightness (SB), geometric parameters, and color profiles, Sérsic fits as well as stellar population properties (such as stellar ages, metallicities, and star formation histories), and emission lines' fluxes within the FOV and the effective radii of the galaxies. We find that the majority of the MaNDala galaxies are star-forming late-type galaxies with 〈nSersic,r〉∼1.6 that are centrals (central/satellite dichotomy). MaNDala covers a large range of SB values (we find 11 candidate ultra-diffuse galaxies and three compact ones), filling the gap between classical dwarfs and low-mass galaxies in the Kormendy Diagram and in the size–mass/luminosity relation, which seems to flatten at 108 2, while the last 20% was at 〈z〉 < 0.3. Finally, a bending of the sSFR-M * relation at M* ∼ 109 M⊙ for the main-sequence galaxies seems to be supported by MaNDala.Publisher PDFPeer reviewe

    CD4 Deficit and Tuberculosis Risk Persist With Delayed Antiretroviral Therapy: 5-Year Data From CIPRA HT-001

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    SETTING: Port-au-Prince, Haiti. OBJECTIVE: To determine long-term effects of early vs. delayed initiation of antiretroviral therapy (ART) on immune recovery and tuberculosis (TB) risk in human immunodeficiency virus (HIV) infected individuals. DESIGN: Open-label randomized controlled trial of immediate ART in HIV-infected adults with CD4 counts between 200 and 350 cells/mm(3) vs. deferring ART until the CD4 count was \u3c200 cells/mm(3). The primary comparisons were CD4 counts over time and risk for incident TB, with 5 years of follow-up. RESULTS: A total of 816 participants were enrolled, with 408 in each treatment arm. The early treatment group started ART within 2 weeks, while the deferred treatment group started ART a median of 1.3 years after enrollment. After 5 years, the mean CD4 count in the early treatment group was significantly higher than in the deferred treatment group (496 cells/mm(3), 95% confidence interval [CI] 477-515 vs. 373 cells/mm(3), 95%CI 357-389; P \u3c 0.0001). TB risk was higher in the deferred treatment group (unadjusted HR 2.41, 95%CI 1.56-3.74; P \u3c 0.0001) and strongly correlated with lower CD4 counts in time-dependent multivariate analysis. CONCLUSION: Delays in ART initiation for HIV-infected adults with CD4 counts of 200-350 cells/mm(3) can result in long-term immune dysfunction and persistent increased risk for TB. TRIAL REGISTRATION: ClinicalTrials.gov NCT00120510

    First evidence of coherent K+K^{+} meson production in neutrino-nucleus scattering

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    Neutrino-induced charged-current coherent kaon production, νμAμK+A\nu_{\mu}A\rightarrow\mu^{-}K^{+}A, is a rare, inelastic electroweak process that brings a K+K^+ on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than neutrino-induced charged-current coherent pion production, because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state K+K^+, μ\mu^- and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at 3σ3\sigma significance.Comment: added ancillary file with information about the six kaon candidate

    Direct Measurement of Nuclear Dependence of Charged Current Quasielastic-like Neutrino Interactions using MINERvA

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    Charged-current νμ\nu_{\mu} interactions on carbon, iron, and lead with a final state hadronic system of one or more protons with zero mesons are used to investigate the influence of the nuclear environment on quasielastic-like interactions. The transfered four-momentum squared to the target nucleus, Q2Q^2, is reconstructed based on the kinematics of the leading proton, and differential cross sections versus Q2Q^2 and the cross-section ratios of iron, lead and carbon to scintillator are measured for the first time in a single experiment. The measurements show a dependence on atomic number. While the quasielastic-like scattering on carbon is compatible with predictions, the trends exhibited by scattering on iron and lead favor a prediction with intranuclear rescattering of hadrons accounted for by a conventional particle cascade treatment. These measurements help discriminate between different models of both initial state nucleons and final state interactions used in the neutrino oscillation experiments
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