1,345 research outputs found
Co-trimoxazole prophylaxis in HIV : the evidence
BibliographyHuman immunodeficiency virus (HIV) damages the body’s
immune system, making secondary (or opportunistic)
infections more common. Treatment and prevention of such
infections is integral to the management of patients with HIV
infection. Co-trimoxazole is a prophylactic treatment that has a
wide range of action against common bacteria, parasites, fungi
and yeasts. As part of a minimum care package, UNAIDS/
WHO recommends co-trimoxazole prophylaxis for HIVinfected
adults with symptomatic disease (WHO stage II, III
or IV), or asymptomatic individuals with CD4 counts ≤500
cells/μl, and for all HIV-positive pregnant women after the
first trimester.1 Co-trimoxazole is also recommended for use in
children with proven HIV infection and infants exposed to HIV
(from 4 - 6 weeks of age until infection with HIV is ruled out).2
The object of this report is to summarise the effects of
co-trimoxazole prophylaxis on morbidity and mortality among
HIV-infected individuals
In-depth analysis of the Naming Game dynamics: the homogeneous mixing case
Language emergence and evolution has recently gained growing attention
through multi-agent models and mathematical frameworks to study their behavior.
Here we investigate further the Naming Game, a model able to account for the
emergence of a shared vocabulary of form-meaning associations through
social/cultural learning. Due to the simplicity of both the structure of the
agents and their interaction rules, the dynamics of this model can be analyzed
in great detail using numerical simulations and analytical arguments. This
paper first reviews some existing results and then presents a new overall
understanding.Comment: 30 pages, 19 figures (few in reduced definition). In press in IJMP
Integrated community case management of childhood illness in low- and middle-income countries
The leading causes of mortality globally in children younger than five years of age (under-fives), and particularly in the regions of sub-Saharan Africa (SSA) and Southern Asia, in 2018 were infectious diseases, including pneumonia (15%), diarrhoea (8%), malaria (5%) and newborn sepsis (7%) (UNICEF 2019). Nutrition-related factors contributed to 45% of under-five deaths (UNICEF 2019). World Health Organization (WHO) and United Nations Children's Fund (UNICEF), in collaboration with other development partners, have developed an approach – now known as integrated community case management (iCCM) – to bring treatment services for children 'closer to home'. The iCCM approach provides integrated case management services for two or more illnesses – including diarrhoea, pneumonia, malaria, severe acute malnutrition or neonatal sepsis – among under-fives at community level (i.e. outside of healthcare facilities) by lay health workers where there is limited access to health facility-based case management services (WHO/UNICEF 2012)
Hofstadter butterflies of carbon nanotubes: Pseudofractality of the magnetoelectronic spectrum
The electronic spectrum of a two-dimensional square lattice in a
perpendicular magnetic field has become known as the Hofstadter butterfly
[Hofstadter, Phys. Rev. B 14, 2239 (1976).]. We have calculated
quasi-one-dimensional analogs of the Hofstadter butterfly for carbon nanotubes
(CNTs). For the case of single-wall CNTs, it is straightforward to implement
magnetic fields parallel to the tube axis by means of zone folding in the
graphene reciprocal lattice. We have also studied perpendicular magnetic fields
which, in contrast to the parallel case, lead to a much richer, pseudofractal
spectrum. Moreover, we have investigated magnetic fields piercing double-wall
CNTs and found strong signatures of interwall interaction in the resulting
Hofstadter butterfly spectrum, which can be understood with the help of a
minimal model. Ubiquitous to all perpendicular magnetic field spectra is the
presence of cusp catastrophes at specific values of energy and magnetic field.
Resolving the density of states along the tube circumference allows recognition
of the snake states already predicted for nonuniform magnetic fields in the
two-dimensional electron gas. An analytic model of the magnetic spectrum of
electrons on a cylindrical surface is used to explain some of the results.Comment: 14 pages, 12 figures update to published versio
Calibration of optimal execution of financial transactions in the presence of transient market impact
Trading large volumes of a financial asset in order driven markets requires
the use of algorithmic execution dividing the volume in many transactions in
order to minimize costs due to market impact. A proper design of an optimal
execution strategy strongly depends on a careful modeling of market impact,
i.e. how the price reacts to trades. In this paper we consider a recently
introduced market impact model (Bouchaud et al., 2004), which has the property
of describing both the volume and the temporal dependence of price change due
to trading. We show how this model can be used to describe price impact also in
aggregated trade time or in real time. We then solve analytically and calibrate
with real data the optimal execution problem both for risk neutral and for risk
averse investors and we derive an efficient frontier of optimal execution. When
we include spread costs the problem must be solved numerically and we show that
the introduction of such costs regularizes the solution.Comment: 31 pages, 8 figure
A Crystal Structure of the Bifunctional Antibiotic Simocyclinone D8, Bound to DNA Gyrase
Simocyclinones are bifunctional antibiotics that inhibit bacterial DNA gyrase by preventing DNA binding to the enzyme. We report the crystal structure of the complex formed between the N-terminal domain of the Escherichia coli gyrase A subunit and simocyclinone D8, revealing two binding pockets that separately accommodate the aminocoumarin and polyketide moieties of the antibiotic. These are close to, but distinct from, the quinolone-binding site, consistent with our observations that several mutations in this region confer resistance to both agents. Biochemical studies show that the individual moieties of simocyclinone D8 are comparatively weak inhibitors of gyrase relative to the parent compound, but their combination generates a more potent inhibitor. Our results should facilitate the design of drug molecules that target these unexploited binding pockets
Biofuels: Beneficial or Bad? Should a Ghanaian chief sell his land for biofuel crop cultivation?
https://deepblue.lib.umich.edu/bitstream/2027.42/143190/1/sustainability_2018_oliphantetal_biofuels.pd
Agricultural cropland extent and areas of South Asia derived using Landsat satellite 30-m time-series big-data using random forest machine learning algorithms on the Google Earth Engine cloud
The South Asia (India, Pakistan, Bangladesh, Nepal, Sri Lanka and Bhutan) has a staggering 900 million
people (~43% of the population) who face food insecurity or severe food insecurity as per United
Nations, Food and Agriculture Organization’s (FAO) the Food Insecurity Experience Scale (FIES). The
existing coarse-resolution (≥250-m) cropland maps lack precision in geo-location of individual farms
and have low map accuracies. This also results in uncertainties in cropland areas calculated fromsuch
products. Thereby, the overarching goal of this study was to develop a high spatial resolution (30-m
or better) baseline cropland extent product of South Asia for the year 2015 using Landsat satellite
time-series big-data and machine learning algorithms (MLAs) on the Google Earth Engine (GEE) cloud
computing platform. To eliminate the impact of clouds, 10 time-composited Landsat bands (blue,
green, red, NIR, SWIR1, SWIR2, Thermal, EVI, NDVI, NDWI) were derived for each of the three timeperiods
over 12 months (monsoon: Days of the Year (DOY) 151–300; winter: DOY 301–365 plus 1–60;
and summer: DOY 61–150), taking the every 8-day data from Landsat-8 and 7 for the years
2013–2015, for a total of 30-bands plus global digital elevation model (GDEM) derived slope band.
This 31-band mega-file big data-cube was composed for each of the five agro-ecological zones
(AEZ’s) of South Asia and formed a baseline data for image classification and analysis. Knowledgebase
for the Random Forest (RF) MLAs were developed using spatially well spread-out reference
training data (N = 2179) in five AEZs. The classification was performed on GEE for each of the five AEZs
using well-established knowledge-base and RF MLAs on the cloud. Map accuracies were measured
using independent validation data (N = 1185). The survey showed that the South Asia cropland
product had a producer’s accuracy of 89.9% (errors of omissions of 10.1%), user’s accuracy of 95.3%
(errors of commission of 4.7%) and an overall accuracy of 88.7%. The National and sub-national
(districts) areas computed from this cropland extent product explained 80-96% variability when
compared with the National statistics of the South Asian Countries. The full-resolution imagery can be
viewed at full-resolution, by zooming-in to any location in South Asia or the world, atwww.croplands.
org and the cropland products of South Asia downloaded from The Land Processes Distributed Active
Archive Center (LP DAAC) of National Aeronautics and Space Administration (NASA) and the United
States Geological Survey (USGS): https://lpdaac.usgs.gov/products/gfsad30saafgircev001/
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