1,604 research outputs found

    Labor market experience and falling earnings inequality in Brazil: 1995–2012

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    The Gini coefficient of labor earnings in Brazil fell by nearly a fifth between 1995 and 2012, from 0.50 to 0.41. The decline in other measures of earnings inequality was even larger, with the 90-10 percentile ratio falling by almost 40 percent. Applying micro-econometric decomposition techniques, this study parses out the proximate determinants of this substantial reduction in earnings inequality. Although a falling education premium did play a role, in line with received wisdom, this study finds that a reduction in the returns to labor market experience was a much more important factor driving lower wage disparities. It accounted for 53 percent of the observed decline in the Gini index during the period. Reductions in horizontal inequalities – the gender, race, regional and urban-rural wage gaps, conditional on human capital and institutional variables – also contributed. Two main factors operated against the decline: a greater disparity in wage premia to different sectors of economic activity, and the “paradox of progress”: the mechanical inequality-increasing effect of a more educated labor force when returns to education are convex

    Back to the Future: Conserving Functional and Phylogenetic Diversity in the Amphibian-Climate Refuges

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    Climate refuges have been used by several species over historical climate change. Ectothermic species often display good models for climate change studies because they are highly sensitive to temperature. Analysis of species loss with ecosystem and evolutionary values helps to understand environmental processes and climate change consequences. We determined the functional and phylogenetic diversity of amphibians in the Atlantic Forest hotspot, using multiple models representing present and future conditions. Through a novel approach, we predict species’ threat status by 2080, following the IUCN’s criterion B1. Our results estimate a drastic reduction in species richness, ecosystem functioning and evolutionary history at low latitudes and altitudes. We show that species will tend to disperse to the areas with milder temperatures (i.e., high latitudes/altitudes). Some of these areas are the same climate refuges that have been suggested for the Late Pleistocene. We highlight that 60% of amphibians can become threatened under predicted-future conditions. This work advances the knowledge on climate refuges for amphibian ecology and evolution, supporting complementary tools for conservation strategies

    Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

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    In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7 degrees to 110 degrees. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene. Published by AIP Publishing

    Stimulation of peripheral Kappa opioid receptors inhibits inflammatory hyperalgesia via activation of the PI3Kγ/AKT/nNOS/NO signaling pathway

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    <p>Abstract</p> <p>Background</p> <p>In addition to their central effects, opioids cause peripheral analgesia. There is evidence showing that peripheral activation of kappa opioid receptors (KORs) inhibits inflammatory pain. Moreover, peripheral μ-opioid receptor (MOR) activation are able to direct block PGE<sub>2</sub>-induced ongoing hyperalgesia However, this effect was not tested for KOR selective activation. In the present study, the effect of the peripheral activation of KORs on PGE<sub>2</sub>-induced ongoing hyperalgesia was investigated. The mechanisms involved were also evaluated.</p> <p>Results</p> <p>Local (paw) administration of U50488 (a selective KOR agonist) directly blocked, PGE<sub>2</sub>-induced mechanical hyperalgesia in both rats and mice. This effect was reversed by treating animals with L-NMMA or N-propyl-L-arginine (a selective inhibitor of neuronal nitric oxide synthase, nNOS), suggesting involvement of the nNOS/NO pathway. U50488 peripheral effect was also dependent on stimulation of PI3Kγ/AKT because inhibitors of these kinases also reduced peripheral antinociception induced by U50488. Furthermore, U50488 lost its peripheral analgesic effect in PI3Kγ null mice. Observations made in vivo were confirmed after incubation of dorsal root ganglion cultured neurons with U50488 produced an increase in the activation of AKT as evaluated by western blot analyses of its phosphorylated form. Finally, immunofluorescence of DRG neurons revealed that KOR-expressing neurons also express PI3Kγ (≅ 43%).</p> <p>Conclusions</p> <p>The present study indicates that activation of peripheral KORs directly blocks inflammatory hyperalgesia through stimulation of the nNOS/NO signaling pathway which is probably stimulated by PI3Kγ/AKT signaling. This study extends a previously study of our group suggesting that PI3Kγ/AKT/nNOS/NO is an important analgesic pathway in primary nociceptive neurons.</p

    MeerKLASS: MeerKAT Large Area Synoptic Survey

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    We discuss the ground-breaking science that will be possible with a wide area survey, using the MeerKAT telescope, known as MeerKLASS (MeerKAT Large Area Synoptic Survey). The current specifications of MeerKAT make it a great fit for science applications that require large survey speeds but not necessarily high angular resolutions. In particular, for cosmology, a large survey over 4,000deg2\sim 4,000 \, {\rm deg}^2 for 4,000\sim 4,000 hours will potentially provide the first ever measurements of the baryon acoustic oscillations using the 21cm intensity mapping technique, with enough accuracy to impose constraints on the nature of dark energy. The combination with multi-wavelength data will give unique additional information, such as exquisite constraints on primordial non-Gaussianity using the multi-tracer technique, as well as a better handle on foregrounds and systematics. Such a wide survey with MeerKAT is also a great match for HI galaxy studies, providing unrivalled statistics in the pre-SKA era for galaxies resolved in the HI emission line beyond local structures at z > 0.01. It will also produce a large continuum galaxy sample down to a depth of about 5\,μ\muJy in L-band, which is quite unique over such large areas and will allow studies of the large-scale structure of the Universe out to high redshifts, complementing the galaxy HI survey to form a transformational multi-wavelength approach to study galaxy dynamics and evolution. Finally, the same survey will supply unique information for a range of other science applications, including a large statistical investigation of galaxy clusters as well as produce a rotation measure map across a huge swathe of the sky. The MeerKLASS survey will be a crucial step on the road to using SKA1-MID for cosmological applications and other commensal surveys, as described in the top priority SKA key science projects (abridged).Comment: Larger version of the paper submitted to the Proceedings of Science, "MeerKAT Science: On the Pathway to the SKA", Stellenbosch, 25-27 May 201

    Sleep pattern and learning in knockdown mice with reduced cholinergic neurotransmission

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    Impaired cholinergic neurotransmission can affect memory formation and influence sleep-wake cycles (SWC). In the present study, we describe the SWC in mice with a deficient vesicular acetylcholine transporter (VAChT) system, previously characterized as presenting reduced acetylcholine release and cognitive and behavioral dysfunctions. Continuous, chronic ECoG and EMG recordings were used to evaluate the SWC pattern during light and dark phases in VAChT knockdown heterozygous (VAChT-KDHET, n=7) and wild-type (WT, n=7) mice. SWC were evaluated for sleep efficiency, total amount and mean duration of slow-wave, intermediate and paradoxical sleep, as well as the number of awakenings from sleep. After recording SWC, contextual fear-conditioning tests were used as an acetylcholine-dependent learning paradigm. The results showed that sleep efficiency in VAChT-KDHET animals was similar to that of WT mice, but that the SWC was more fragmented. Fragmentation was characterized by an increase in the number of awakenings, mainly during intermediate sleep. VAChT-KDHET animals performed poorly in the contextual fear-conditioning paradigm (mean freezing time: 34.4±3.1 and 44.5±3.3 s for WT and VAChT-KDHET animals, respectively), which was followed by a 45% reduction in the number of paradoxical sleep episodes after the training session. Taken together, the results show that reduced cholinergic transmission led to sleep fragmentation and learning impairment. We discuss the results on the basis of cholinergic plasticity and its relevance to sleep homeostasis. We suggest that VAChT-KDHET mice could be a useful model to test cholinergic drugs used to treat sleep dysfunction in neurodegenerative disorders.Universidade Federal de São Paulo (UNIFESP) Departamento de FisiologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de PsicobiologiaUniversidade Federal do Rio Grande do Norte Instituto do CerebroUniversidade Federal do ABC Computacao e Cognicao Centro de MatematicaUniversidade Federal de Minas Gerais Departamento de Fisiologia e Biofisica Nucleo de NeurocienciasUniversity of Western Ontario Department of Physiology and Pharmacology and Department of Anatomy and Cell Biology Robarts Research InstituteUNIFESP, Depto. de FisiologiaUNIFESP, Depto. de PsicobiologiaSciEL

    Efferent Pathways in Sodium Overload-Induced Renal Vasodilation in Rats

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    Hypernatremia stimulates the secretion of oxytocin (OT), but the physiological role of OT remains unclear. the present study sought to determine the involvement of OT and renal nerves in the renal responses to an intravenous infusion of hypertonic saline. Male Wistar rats (280-350 g) were anesthetized with sodium thiopental (40 mg. kg(-1), i.v.). A bladder cannula was implanted for collection of urine. Animals were also instrumented for measurement of mean arterial pressure (MAP) and renal blood flow (RBF). Renal vascular conductance (RVC) was calculated as the ratio of RBF by MAP. in anesthetized rats (n = 6), OT infusion (0.03 mu g . kg(-1), i.v.) induced renal vasodilation. Consistent with this result, ex vivo experiments demonstrated that OT caused renal artery relaxation. Blockade of OT receptors (OXTR) reduced these responses to OT, indicating a direct effect of this peptide on OXTR on this artery. Hypertonic saline (3 M NaCl, 1.8 ml . kg(-1) b.wt., i.v.) was infused over 60 s. in sham rats (n = 6), hypertonic saline induced renal vasodilation. the OXTR antagonist (AT; atosiban, 40 mu g . kg(-1) . h(-1), i.v.; n = 7) and renal denervation (RX) reduced the renal vasodilation induced by hypernatremia. the combination of atosiban and renal denervation (RX+AT; n = 7) completely abolished the renal vasodilation induced by sodium overload. Intact rats excreted 51% of the injected sodium within 90 min. Natriuresis was slightly blunted by atosiban and renal denervation (42% and 39% of load, respectively), whereas atosiban with renal denervation reduced sodium excretion to 16% of the load. These results suggest that OT and renal nerves are involved in renal vasodilation and natriuresis induced by acute plasma hypernatremia.Fundacao de Amparo a Pesquisa do Estado de Goias (FAPEG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Fed Goias, Ctr Neurosci & Cardiovasc Physiol, Inst Biol Sci, Dept Physiol Sci, Goiania, Go, BrazilUniv Fed Uberlandia, Fac Phys Educ, Inst Biol Sci, BR-38400 Uberlandia, MG, BrazilUniversidade Federal de São Paulo, Dept Physiol, São Paulo, BrazilUniv Fed Goias, Inst Biol Sci, Mol Biol Lab, Goiania, Go, BrazilUniv Fed Goias, Inst Biol Sci, Dept Biochem & Mol Biol, Goiania, Go, BrazilUniversidade Federal de São Paulo, Dept Physiol, São Paulo, BrazilFundacao de Amparo a Pesquisa do Estado de Goias (FAPEG): 2012/0055431086Fundacao de Amparo a Pesquisa do Estado de Goias (FAPEG): 2009/10267000352CNPq: 477832/2010-5CNPq: 483411/2012-4Web of Scienc
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