36,654 research outputs found
Thermal dependence of the zero-bias conductance through a nanostructure
We show that the conductance of a quantum wire side-coupled to a quantum dot,
with a gate potential favoring the formation of a dot magnetic moment, is a
universal function of the temperature. Universality prevails even if the
currents through the dot and the wire interfere. We apply this result to the
experimental data of Sato et al.[Phys. Rev. Lett. 95, 066801 (2005)].Comment: 6 pages, 3 figures. More detailed presentation, and updated
references. Final version
The art of HIV elimination: past and present science
Introduction: Remarkable strides have been made in controlling the HIV epidemic, although not enough to achieve epidemic control. More recently, interest in biomedical HIV control approaches has increased, but substantial challenges with the HIV cascade of care hinder successful implementation. We summarise all available HIV prevention methods and make recommendations on how to address current challenges.
Discussion: In the early days of the epidemic, behavioural approaches to control the HIV dominated, and the few available evidence-based interventions demonstrated to reduce HIV transmission were applied independently from one another. More recently, it has become clear that combination prevention strategies targeted to high transmission geographies and people at most risk of infections are required to achieve epidemic control. Biomedical strategies such as male medical circumcision and antiretroviral therapy for treatment in HIV-positive individuals and as preexposure prophylaxis in HIV-negative individuals provide immense promise for the future of HIV control. In resourcerich settings, the threat of HIV treatment optimism resulting in increased sexual risk taking has been observed and there are concerns that as ART roll-out matures in resource-poor settings and the benefits of ART become clearly visible, behavioural disinhibition may also become a challenge in those settings. Unfortunately, an efficacious vaccine, a strategy which could potentially halt the HIV epidemic, remains elusive.
Conclusion: Combination HIV prevention offers a logical approach to HIV control, although what and how the available options should be combined is contextual. Therefore, knowledge of the local or national drivers of HIV infection is paramount. Problems with the HIV care continuum remain of concern, hindering progress towards the UNAIDS target of 90-90-90 by 2020. Research is needed on combination interventions that address all the steps of the cascade as the steps are not independent of each other. Until these issues are addressed, HIV elimination may remain an unattainable goal
Desenvolvimento de um portal colaborativo da Sustentabilidade da Cana-de-Açúcar e oja na Região Centro-Sul.
Este trabalho apresenta a criação do portal do SustenAgro criado no ambiente da Agropedia brasilis, a partir da criação de uma organização onde serão adicionados os membros da equipe do projeto e suas respectivas permissões
Does Good Mutation Help You Live Longer?
We study the dynamics of an age-structured population in which the life
expectancy of an offspring may be mutated with respect to that of its parent.
When advantageous mutation is favored, the average fitness of the population
grows linearly with time , while in the opposite case the average fitness is
constant. For no mutational bias, the average fitness grows as t^{2/3}. The
average age of the population remains finite in all cases and paradoxically is
a decreasing function of the overall population fitness.Comment: 4 pages, 2 figures, RevTeX revised version, to appear in Phys. Rev.
Let
Acesso aberto à informação de solos brasileiros.
O objetivo deste trabalho foi demonstrar as formas de acesso aos dados e as etapas para a realização de consultas públicas, via Internet.CIIC 2014. Nº 14605
Cosmology in the Solar System: Pioneer effect is not cosmological
Does the Solar System and, more generally, a gravitationally bound system
follow the cosmic expansion law ? Is there a cosmological influence on the
dynamics or optics in such systems ? The general relativity theory provides an
unique and unambiguous answer, as a solution of Einstein equations with a local
source in addition to the cosmic fluid, and obeying the correct (cosmological)
limiting conditions. This solution has no analytic expression. A Taylor
development of its metric allows a complete treatment of dynamics and optics in
gravitationally bound systems, up to the size of galaxy clusters, taking into
account both local and cosmological effects. In the solar System, this provides
an estimation of the (non zero) cosmological influence on the Pioneer probe: it
fails to account for the " Pioneer effect " by about 10 orders of magnitude. We
criticize contradictory claims on this topic
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