389 research outputs found

    AIDS and the gender gap in life expectancy in Africa

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    In sub-Saharan Africa, the majority of people living with HIV are women. Yet the number of AIDS-related deaths in this region is higher among men and the gender gap in life expectancy has expanded in recent years. Bruno Masquelier and Georges Reniers explain the reasons behind this paradox

    Comparative study of the phase transition of Li1+xMn2-xO4 by anelastic spectroscopy and differential scanning calorimetry

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    Li1+xMn2xO4 is one of the most promising candidates as high performance cathode for lithium ion batteries. The stoichiometric compound is known to undergo a phase transition around room temperature, which has been widely studied and attributed either to Jahn–Teller effect or to charge ordering. For the applications it is important to suppress this phase transition, which lowers the electrochemical performances of the material. DSC measurements, which have been largely used in the literature to study the occurrence of the transformation, can detect a phase transition accompanied by latent heat only for x < 0.04. This fact has been generally accepted as a proof that the transformation is suppressed by doping. However, by using a technique extremely sensitive to rearrangements of atoms in the lattice, such as anelastic spectroscopy, we show that the phase transition persists up to x = 0.08, is shifted to lower temperatures, and changes its nature from first to higher order. The implications for the mechanism driving the transition and the similarities and differences with doped Fe3O4, which is the prototype of charge order transitions, are discussed

    The Future Mortality of High Mortality Countries: A Model Incorporating Expert Arguments

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    This paper examines the future of mortality in the 65 countries still experiencing high mortality in 2010, as defined by a cutoff of 40 deaths before age five per thousand live births. Mortality declines in several countries stagnated or reversed in the last two decades of the twentieth century due mainly to HIV/AIDS. The forces underlying past mortality trends and affecting the future course of mortality are examined by reviewing the existing literature and reporting the results of the global survey and invited meeting, both involving mortality experts. The experts assessed the likelihood and weight of forces hypothesized to influence mortality. A statistical model is combined with these expert assessments to produce a set of mortality assumptions that are incorporated into the projections reported in this paper. This paper also addresses the limited availability of reliable data on age-specific mortality rates

    The epidemiological transition in Antananarivo, Madagascar: an assessment based on death registers (1900–2012)

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    Background: Madagascar today has one of the highest life expectancies in sub-Saharan Africa, despite being among the poorest countries in the continent. There are relatively few detailed accounts of the epidemiological transition in this country due to the lack of a comprehensive death registration system at the national level. However, in Madagascar's capital city, death registration was established around the start of the 20th century and is now considered virtually complete. Objective: We provide an overview of trends in all-cause and cause-specific mortality in Antananarivo to document the timing and pace of the mortality decline and the changes in the cause-of-death structure. Design: Death registers covering the period 1976–2012 were digitized and the population at risk of dying was estimated from available censuses and surveys. Trends for the period 1900–1976 were partly reconstructed from published sources. Results: The crude death rate stagnated around 30‰ until the 1940s in Antananarivo. Mortality declined rapidly after the World War II and then resurged again in the 1980s as a result of the re-emergence of malaria and the collapse of Madagascar's economy. Over the past 30 years, impressive gains in life expectancy have been registered thanks to the unabated decline in child mortality, despite political instability, a lasting economic crisis and the persistence of high rates of chronic malnutrition. Progress in adult survival has been more modest because reductions in infectious diseases and diseases of the respiratory system have been partly offset by increases in cardiovascular diseases, neoplasms, and other diseases, particularly at age 50 years and over. Conclusions: The transition in Antananarivo has been protracted and largely dependent on anti-microbial and anti-parasitic medicine. The capital city now faces a double burden of communicable and non-communicable diseases. The ongoing registration of deaths in the capital generates a unique database to evaluate the performance of the health system and measure intervention impacts

    Crystal Structures, Local Atomic Environments, and Ion Diffusion Mechanisms of Scandium-Substituted Sodium Superionic Conductor (NASICON) Solid Electrolytes

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    The importance of exploring new solid electrolytes for all-solid-state batteries has led to significant interest in NASICON-type materials. Here, the Sc3+-substituted NASICON compositions Na3ScxZr2-x(SiO4)2-x(PO4)1+x (termed N3) and Na2ScyZr2-y(SiO4)1-y(PO4)2+y (termed N2) (x, y = 0 – 1) are studied as model Na+-ion conducting electrolytes for solid-state batteries. The influence of Sc3+ substitution on the crystal structures and local atomic environments has been characterized by powder X-ray diffraction (XRD) and neutron powder diffraction (NPD), as well as solid-state 23Na, 31P, and 29Si nuclear magnetic resonance (NMR) spectroscopy. A phase transition between 295 and 473 K from monoclinic C2/c to rhombohedral R c is observed for the N3 compositions, while N2 compositions crystallize in a rhombohedral R c unit cell in this temperature range. Alternating current (AC) impedance spectroscopy, molecular dynamics (MD) and high temperature 23Na NMR are in good agreement, showing that with a higher Sc3+ concentration, the ionic conductivity (about 10-4 S/cm at 473 K) decreases and the activation energy for ion diffusion increases. 23Na NMR experiments indicate that the nature of the Na+-ion motion is two-dimensional on the local atomic scale of NMR though the long-range diffusion pathways are three-dimensional. In addition, a combination of MD, bond valence, maximum entropy/Rietveld and van Hove correlation methods has been used, to reveal that the Na+-ion diffusion in these NASICON materials is three-dimensional and that there is a continuous exchange of sodium between Na(1) and Na(2) sites

    Prevalence of resistance mutations related to integrase inhibitor S/GSK1349572 in HIV-1 subtype B raltegravir-naive and -treated patients

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    Objectives To compare the frequency of previously in vitro-selected integrase mutations (T124A, T124A/S153F, S153Y, T124A/S153Y and L101I/T124A/S153Y) conferring resistance to S/GSK1349572 between HIV-1 subtype B integrase inhibitor (INI)-naive and raltegravir-treated patients. Methods Integrase sequences from 650 INI-naive patients and 84 raltegravir-treated patients were analysed. Results The T124A mutation alone and the combination T124A/L101I were more frequent in raltegravir-failing patients than in INI-naive patients (39.3% versus 24.5%, respectively, P = 0.005 for T124A and 20.2% versus 10.0%, respectively, P = 0.008 for T124A/L101I). The S153Y/F mutations were not detected in any integrase sequence (except for S153F alone, only detected in one INI-naive patient). Conclusions T124A and T124A/L101I, more frequent in raltegravir-treated patients, could have some effect on raltegravir response and their presence could play a role in the selection of other mutations conferring S/GSK1349572 resistance. The impact of raltegravir-mediated changes such as these on the virological response to S/GSK1349572 should be studied further

    Model Kebijakan Penanggulangan Korupsi di Universitas Negeri YOGYAKARTA

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    Penelitian ini bertujuan untuk mengetahui kebijakan Universitas Negeri Yogyakarta dalam menanggulangi korupsi dan menemukan model kebijakan yang diinginkan Universitas Negeri Yogyakarta dalam menanggulangi korupsi. Penelitian ini adalah penelitian survei dengan pendekatan kuantitatif dan kualitatif. Sampel penelitian ditentukan secara multy stage sampling dengan teknik pengumpulan data dengan angket, dokumen dan diperkuat dengan pengumpulan data melalui Focus Group Discussion (FGD), dan validasi instrumen melalui validitas isi (content validity). Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa kebijakan penanggulangan korupsi di UNY tidak ada secara khusus dikeluarkan. Kebijakan yang ada mengikuti dan mempertahankan kebijakan yang lebih tinggi, yaitu dari Pemerintah. Model kebijakan penangggulangan korupsi di UNY yang digunakan adalah Model Rasional, yaitu kebijakan penanggulangan korupsi yang dikeluarkan merupakan aspirasi semua staf yang ada di unit kerja dan harus menekankan pada aspek efisiensi atas beban kerja pada unit kerja yang bersangkutan. Adapun kebijakan yang sudah ada yang berasal dari Pemerintah pusat dijadikan pedoman

    STDP Allows Fast Rate-Modulated Coding with Poisson-Like Spike Trains

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    Spike timing-dependent plasticity (STDP) has been shown to enable single neurons to detect repeatedly presented spatiotemporal spike patterns. This holds even when such patterns are embedded in equally dense random spiking activity, that is, in the absence of external reference times such as a stimulus onset. Here we demonstrate, both analytically and numerically, that STDP can also learn repeating rate-modulated patterns, which have received more experimental evidence, for example, through post-stimulus time histograms (PSTHs). Each input spike train is generated from a rate function using a stochastic sampling mechanism, chosen to be an inhomogeneous Poisson process here. Learning is feasible provided significant covarying rate modulations occur within the typical timescale of STDP (∌10–20 ms) for sufficiently many inputs (∌100 among 1000 in our simulations), a condition that is met by many experimental PSTHs. Repeated pattern presentations induce spike-time correlations that are captured by STDP. Despite imprecise input spike times and even variable spike counts, a single trained neuron robustly detects the pattern just a few milliseconds after its presentation. Therefore, temporal imprecision and Poisson-like firing variability are not an obstacle to fast temporal coding. STDP provides an appealing mechanism to learn such rate patterns, which, beyond sensory processing, may also be involved in many cognitive tasks
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