5,936 research outputs found
Natural history of a visceral leishmaniasis outbreak in highland Ethiopia
In May 2005, visceral leishmaniasis (VL) was recognized for the first time in Libo Kemken, Ethiopia, a highland region where only few cases had been reported before. We analyzed records of VL patients treated from May 25, 2005 to December 13, 2007 by the only VL treatment center in the area, maintained by Médecins Sans Frontières-Ethiopia, Operational Center Barcelona-Athens. The median age was 18 years; 77.6% were male. The overall case fatality rate was 4%, but adults 45 years or older were five times as likely to die as 5-29 year olds. Other factors associated with increased mortality included HIV infection, edema, severe malnutrition, pneumonia, tuberculosis, and vomiting. The VL epidemic expanded rapidly over a several-year period, culminating in an epidemic peak in the last third of 2005, spread over two districts, and transformed into a sustained endemic situation by 2007
Charged Annular Disks and Reissner-Nordstr\"{o}m Type Black Holes from Extremal Dust
We present the first analytical superposition of a charged black hole with an
annular disk of extremal dust. In order to obtain the solutions, we first solve
the Einstein-Maxwell field equations for sources that represent disk-like
configurations of matter in confomastatic spacetimes by assuming a functional
dependence among the metric function, the electric potential and an auxiliary
function,which is taken as a solution of the Laplace equation. We then employ
the Lord Kelvin Inversion Method applied to models of finite extension in order
to obtain annular disks. The structures obtained extend to infinity, but their
total masses are finite and all the energy conditions are satisfied. Finally,
we observe that the extremal Reissner-Nordstr\"{o}m black hole can be embedded
into the center of the disks by adding a boundary term in the inversion.Comment: 17 revtex pages, 8 eps figure
Influence of thermomechanical processing parameters on critical temperatures to develop an Advanced High-Strength Steel microstructure
A good selection of the thermomechanical processing parameters will optimize the function of alloying elements to get the most of mechanical properties in Advanced High-Strength Steels for automotive components, where high resistance is required for passenger safety. As such, critical processing temperatures must be defined taking into account alloy composition, in order for effective thermomechanical processing schedules to be designed. These critical temperatures mainly include the recrystallization stop temperature (T5%) and the transformation temperatures (Ar1, Ar3, Bs, etc.). These critical processing temperatures were characterized using different thermomechanical conditions. T5% was determined through the softening evaluation on double hit tests and the observation of prior austenite grain boundaries on the microstructure. Phase transformation temperatures were measured by dilatometry experiments at different cooling rates. The results indicate that the strain per pass and the interpass time will influence the most on the determination of T5%. The range of temperatures between the recrystallized and non-recrystallized regions can be as narrow as 30 °C at a higher amount of strain. The proposed controlled thermomechanical processing schedule involves getting a severely deformed austenite with a high dislocation density and deformation bands to increase the nucleation sites to start the transformation products. This microstructure along with a proper cooling strategy will lead to an enhancement in the final mechanical properties of a particular steel composition
Low-energy effects in brane worlds: Liennard-Wiechert potentials and Hydrogen Lamb shift
Testing extra dimensions at low-energies may lead to interesting effects. In
this work a test point charge is taken to move uniformly in the 3-dimensional
subspace of a (3+)-brane embedded in a (3++1)-space with compact and
one warped infinite spatial extra dimensions. We found that the electromagnetic
potentials of the point charge match standard Liennard-Wiechert's at large
distances but differ from them close to it. These are finite at the position of
the charge and produce finite self-energies. We also studied a localized
Hydrogen atom and take the deviation from the standard Coulomb potential as a
perturbation. This produces a Lamb shift that is compared with known
experimental data to set bounds for the parameter of the model. This work
provides details and extends results reported in a previous Letter.Comment: Manuscript (LaTeX) and 2 figure files (eps format) used by the
manuscript LaTeX fil
AGRONOMIC EVALUATION AND CHEMICAL COMPOSITION OF AFRICAN STAR GRASS (Cynodon plectostachyus) IN THE SOUTHERN REGION OF THE STATE OF MEXICO
African Star Grass is one of the forage resources most commonly used by farmers in regions with warm-humid climates. This study was carried out to determine the nutritional and agronomic characteristics of African Star Grass (Cynodon plectostachyus) through the following variables: crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), organic matter digestibility (OMD), net forage accumulation (NFA), stem:leaf ratio, and live:dead matter ratio in the three pastures evaluated. The work took place from April 2007 to March 2008, with evaluations carried out on a monthly basis. The data were analyzed in a randomized block design in which the blocks were the pastures, and the treatments were the months of evaluation. There were no differences between the pastures evaluated for the NDF, ADF or OMD (P>0.05). Differences were found, however, in CP, while in the monthly evaluation, differences were found between the periods evaluated (P<0.05) for these variables. Differences were also found in the agronomic evaluation of pastures (P<0.05) among height of pasture, net forage accumulation (NFA), live matter, dead matter, leaf and stem, both among pastures and in the monthly evaluations. African Star Grass can therefore be considered a good choice for milk production systems in the southern region of the state of Mexico, due to its nutritional and agronomic characteristics
Holographic zero sound at finite temperature in the Sakai-Sugimoto model
In this paper, we study the fate of the holographic zero sound mode at finite
temperature and non-zero baryon density in the deconfined phase of the
Sakai-Sugimoto model of holographic QCD. We establish the existence of such a
mode for a wide range of temperatures and investigate the dispersion relation,
quasi-normal modes, and spectral functions of the collective excitations in
four different regimes, namely, the collisionless quantum, collisionless
thermal, and two distinct hydrodynamic regimes. For sufficiently high
temperatures, the zero sound completely disappears, and the low energy physics
is dominated by an emergent diffusive mode. We compare our findings to
Landau-Fermi liquid theory and to other holographic models.Comment: 1+24 pages, 19 figures, PDFTeX, v2: some comments and references
added, v3: some clarifications relating to the different regimes added,
matches version accepted for publication in JHEP, v4: corrected typo in eq.
(3.18
Stress Management Strategies in Esports: An Exploratory Online Survey on Applied Practice
Given the competitive nature of esports (e.g., maintaining focus and adaptive coping) and the increasing interest from practitioners in addressing stress management issues, empirical evidence on stress management strategies is needed that is tailored to the unique demands of esports. To ensure that ethical and professional standards are being met, it is important to first explore the factors that practitioners perceive to negatively impact the performance of esports players and the stress management strategies that are currently being used to support these players. Therefore, an online survey of 25 practitioners was conducted with results highlighting a variety of factors that were perceived to negatively impact players’ performance such as players’ ability to cope and lack of self-confidence. In addition, stress management strategies used before and after competition most frequently included strategies such as imagery, breathing techniques, and social support. Future research directions, limitations, and practical implications are discussed
As contradições do processo de desenvolvimento agrícola na Transamazônica.
bitstream/item/57538/1/CPATU-Doc93.pd
Quantic Analysis of Formation of a Biomaterial of Latex, Retinol, and Chitosan for Biomedical Applications
The present work shows the quantum theoretical analysis and practical tests for the formation of a homogeneous mixture with Latex (Lx), Chitosan (Qn) and Retinol (Rl), which work as possible biomaterial for regeneration of epithelial tissue. Lx, Qn, and Rl compounds molecules were designed through Hyperchem to get the coefficient of electrostatic potential calculations. The amounts used to create the biomaterial are minimum depending on the quantities of molecules used in chemical design. A positive calculation was obtained for the reaction of these three compounds and the formation of the biomaterial in physical checking theory etc
Quantic Analysis of the Adherence of a Gram-Negative Bacteria in A HEPA Filter
It is known that Gram-negative bacteria (GNB) are the most frequent bacteria in hospital units. It is also known that GNBs generate a greater number of nosocomial infections in critical areas. In the present work, the adhesion of the bacterial cell wall (BCW) to the compounds of the material layers of a high efficiency filter (HEPA) was analyzed. The analysis was carried out by means of molecular simulation and quantum chemistry. The BCW and HEPA molecules were designed using Hyperchem software for simulation. The calculations of the quantum interactions of the molecules were carried out using the theory of the electron transfer coefficient (ETC). It obtained from 4 to 6 compounds that are more likely to interact even as a chemical reaction. The compounds of the glass fibers are the ones that work best for the adhesion and destruction of the BCW
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