499 research outputs found
Livelihood Risk from HIV in Semi-Arid Tropics of Rural Andhra Pradesh
This paper discusses the livelihood dynamics in the fragile landscape of the semi arid tropics (SAT) of Andhra Pradesh. SAT is home to the poorest of the poor who live in conditions of persistent drought, subsistence agriculture and poor access to markets. This paper is a case study focusing particularly on labour migration, its role in influencing the health risk behaviour of migrants and in the spread of the HIV epidemic among SAT rural households. The most vulnerable population in these drought prone regions are the migrant labourers, and their vulnerability is influenced by three major factors?the vulnerability and unstable productivity in the degraded and marginal landscape, the caste system that has traditionally kept them backward and vulnerable, and experiences in the external environment to which they migrate. This study?based on a theoretical framework, whereby livelihood risks lead to health risks, particularly HIV infection?outlines the process that causes a further deterioration of the household and the occurrence of cyclical health risk. The paper calls for a multisectoral approach to tackle the issue of migrant vulnerability, and for interventions with a more migrant-need sensitive approach.labour migration, HIV risk behaviour, agriculture, health, semi-arid tropics
Livelihood Risk from HIV in Semi-Arid Tropics of Rural Andhra Pradesh
This paper discusses the livelihood dynamics in the fragile landscape of the semi-arid tropics (SAT) of Andhra Pradesh. SAT is home to the poorest of the poor who live in conditions of persistent drought, subsistence agriculture and poor access to markets. This paper is a case study focusing particularly on labour migration, its role in influencing the health risk behaviour of migrants and in the spread of the HIV epidemic among SAT rural households. The most vulnerable population in these drought prone regions are the migrant labourers, and their vulnerability is influenced by three major factorsâthe vulnerability and unstable productivity in the degraded and marginal landscape, the caste system that has traditionally kept them backward and vulnerable, and experiences in the external environment to which they migrate. This study is based on a theoretical framework, whereby livelihood risks lead to health risks, particularly HIV infectionâoutlines the process that causes a further deterioration of the household and the occurrence of cyclical health risk. The paper calls for a multisectoral approach to tackle the issue of migrant vulnerability, and for interventions with a more migrant-need sensitive approach.
Congestion-aware wireless network-on-chip for high-speed communication
The design of system-on-chip (SoC) requires the complex integration between a multi-number of cores on a single chip. To establish the effective communication between multiple cores there aremore challenging issues on designing the network-on-chip (NoC) architectures. The proposed system deals with the utilization of on-chip antennas for the wireless communication between the long distance cores to minimize the latency and power. In this proposed work, we have designed high-speed wireless NoC (WiNoC) for on-chip communication. This high-speed WiNoC has been achieved by designing a congestion measure unit, which monitors and measures the congestion in the input data and establishes the effective wireless communication between the output channels and routers. The designed architecture is synthesized and implemented by using Altera Quartus II, where the SoC is designed using Qsys builder. The proposed WiNoC shows better performance parameters like throughput, latency and power than the conventional NoC
High count rate {\gamma}-ray spectroscopy with LaBr3:Ce scintillation detectors
The applicability of LaBr3:Ce detectors for high count rate {\gamma}-ray
spectroscopy is investigated. A 3"x3" LaBr3:Ce detector is used in a test setup
with radioactive sources to study the dependence of energy resolution and photo
peak efficiency on the overall count rate in the detector. Digitized traces
were recorded using a 500 MHz FADC and analysed with digital signal processing
methods. In addition to standard techniques a pile-up correction method is
applied to the data in order to further improve the high-rate capabilities and
to reduce the losses in efficiency due to signal pile-up. It is shown, that
{\gamma}-ray spectroscopy can be performed with high resolution at count rates
even above 1 MHz and that the performance can be enhanced in the region between
500 kHz and 10 MHz by using pile-up correction techniques
DATA FUSION OF PANCHROMATIC AND MULTISPECTRAL IMAGES BASED ON OPTIMIZATION USING LAGRANGE MULTIPLIER
The remote sensing satellites provide complementary images of different resolutions which need to be integrated using the techniques of image fusion. In this paper, image fusion using the IKONOS satellite data is discussed. Unlike other models which are based on sensor model, our approach is data centric including the effects of the sensor as well as the reflectance characteristics of the imaged object. A linear relationship is built between the panchromatic channel and the multispectral channel data. We then formulate a minimisation function in terms of Lagrange multiplier to optimally maximise the spectral consistency and minimise the error in variance. The variances of the downsampled multispectral channels are observed and compared with the original multispectral data. A chi-square goodness of fit test is performed to evaluate the data computed based on our algorithm. Simulation results are presented using the IKONOS 1m resolution panchromatic and 4 m resolution multispectral data
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The Effect of Ion Implanting on Hydrogen Entry into Metals
The effectiveness of platinum ion implanting in mitigating hydrogen entry into 4340 steel is measured and quantified. Data are presented to compare the extent of hydrogen absorption by the substrate during electrolytic hydrogen charging of platinum ion-implanted and unimplanted 4340 steel substrates. Several implanting conditions were used in processing the samples, and the surface-limited mass-transfer coefficient was calculated for each case and used to quantify the effectiveness of each treatment in reducing hydrogen absorption. It is shown that the underlying mechanism for reducing hydrogen absorption by platinum ion-implanted substrates is the catalytic effect of platinum that favors hydrogen evolution at the steel\u27s surface over hydrogen absorption by the metal. Although scattering experiments with low energy helium ions suggest that the platinum content in the first monolayer of platinum-implanted steels is small, the ability of Pt to catalyze the hydrogen evolution reaction is still strong enough to significantly reduce the quantity of hydrogen that enters the metal
Atomistic Simulation of Water Percolation and Proton Hopping in Nafion Fuel Cell Membrane
We have performed a detailed analysis of water clustering and percolation in hydrated Nafion configurations generated by classical molecular dynamics simulations. Our results show that at low hydration levels H2O molecules are isolated and a continuous hydrogen-bonded network forms as the hydration level is increased. Our quantitative analysis has established a hydration level (λ) between 5 and 6 H2O/SO3â as the percolation threshold of Nafion. We have also examined the effect of such a network on proton transport by studying the structural diffusion of protons using the quantum hopping molecular dynamics method. The mean residence time of the proton on a water molecule decreases by 2 orders of magnitude when the λ value is increased from 5 to 15. The proton diffusion coefficient in Nafion at a λ value of 15 is about 1.1 Ă 10â5 cm2/s in agreement with experiment. The results provide quantitative atomic-level evidence of water network percolation in Nafion and its effect on proton conductivity
Theoretical calculations of the primary defects induced by pions and protons in SiC
In the present work, the bulk degradation of SiC in hadron (pion and proton)
fields, in the energy range between 100 MeV and 10 GeV, is characterised
theoretically by means of the concentration of primary defects per unit
fluence. The results are compared to the similar ones corresponding to diamond,
silicon and GaAs.Comment: 9 pages, 2 figures, in press to Nuclear Instruments and Methods in
Physics Research A v2 - modified title, and major revision
TAR-RNA recognition by a novel cyclic aminoglycoside analogue
The formation of the Tat-protein/TAR-RNA complex is a crucial step in the regulation of human immunodeficiency virus (HIV)-gene expression. To obtain full-length viral transcripts the Tat/TAR complex has to recruit the positive transcription elongation factor complex (P-EFTb), which interacts with TAR through its cyclin T1 (CycT1) component. Mutational studies identified the TAR hexanucleotide loop as a crucial region for contacting CycT1. Interfering with the interaction between the Tat/CycT1 complex and the TAR-RNA is an attractive strategy for the design of anti-HIV drugs. Positively charged molecules, like aminoglycosides or peptidomimetics, bind the TAR-RNA, disrupting the Tat/TAR complex. Here, we investigate the complex between the HIV-2 TAR-RNA and a neooligoaminodeoxysaccharide by NMR spectroscopy. In contrast to other aminoglycosides, this novel aminoglycoside analogue contacts simultaneously the bulge residues required for Tat binding and the A35 residue of the hexanucleotide loop. Upon complex formation, the loop region undergoes profound conformational changes. The novel binding mode, together with the easy accessibility of derivatives for the neooligoaminodeoxysaccharide, could open the way to the design of a new class of TAR-RNA binders, which simultaneously inhibit the formation of both the Tat/TAR binary complex and the Tat/TAR/CycT1 ternary complex by obstructing both the bulge and loop regions of the RNA
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A unified description of crystalline-to-amorphous transitions
Amorphous metallic alloys can now be synthesized by a variety of solid-state processes demonstrating the need for a more general approach to crystalline-to-amorphous (c-a) transitions. By focusing on static atomic displacements as a measure of chemical and topological disorder, we show that a unified description of c-a transformations can be based on a generalization of the phenomenological melting criterion proposed by Lindemann. The generalized version assumes that melting of a defective crystal occurs whenever the sum of thermal and static mean-square displacements exceeds a critical value identical to that for melting of the defect-free crystal. This implies that chemical or topological disorder measured by static displacements is thermodynamically equivalent to heating, and therefore that the melting temperature of the defective crystal will decrease with increasing amount of disorder. This in turn implies the existence of a critical state of disorder where the melting temperature becomes equal to a glass-transition temperature below which the metastable crystal melts to a glass. The generalized Lindemann melting criterion leads naturally to an interpretation of c-a transformations as defect-induced, low-temperature melting of critically disordered crystals. Confirmation of this criterion is provided by molecular-dynamics simulations of heat-induced melting and of defect-induced amorphization of intermetallic compounds caused either by the production of Frenkel pairs or anti-site defects. The thermodynamic equivalence between static atomic disorder and heating is reflected in the identical softening effects which they have on elastic properties and also in the diffraction analysis of diffuse scattering from disordered crystals, where the effect of static displacements appears as an artificially-enlarged thermal Debye-Waller factor. Predictions of this new, unified approach to melting and amorphization are compared with available experimental information
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