20,195 research outputs found
Successful paediatric HIV treatment in rural primary care in Africa
<p>Objective: Clinical outcomes of HIV-infected children on antiretroviral treatment (ART) in a decentralised, nurse/counsellor-led programme.</p>
<p>Design: Clinical cohort.</p>
<p>Setting: KwaZulu-Natal, South Africa.</p>
<p>Patients: HIV-infected children aged <= 15 years on ART, June 2004-2008.</p>
<p>Main outcome measures: Survival according to baseline characteristics including age, WHO clinical stage, haemoglobin and CD4%, was assessed in Kaplan-Meier analyses. Hazard ratios for mortality were estimated using Cox proportional hazards regression and changes in laboratory parameters and weight-for-age z scores after 6-12 months' treatment were calculated.</p>
<p>Results: 477 HIV-infected children began ART at a median age of 74 months (range 4-180), median CD4 count (CD4%) of 433 cells/mm(3) (17%) and median HIV viral load of log 4.2 copies/ml; 105 (22%) were on treatment for tuberculosis and 317 (76.6%) were WHO stage 3/4. There were significant increases after ART initiation in CD4% (17% vs 22%; p<0.001), haemoglobin (9.9 vs 11.7 g/l; p <= 0.001) and albumin (30 vs 36 g/l; p <= 0.001). 32 (6.7%) children died over 732 child-years of follow-up (43.7 deaths/1000 child-years; 95% CI 32.7 to 58.2), 17 (53.1%) within 90 days of treatment initiation; median age of death was 84 (IQR 10-181) months. Children with baseline haemoglobin <= 8 g/l were more likely to die (adjusted HR 4.5; 95% CI 1.6 to 12.3), as were those aged <18 months compared with >60 months (adjusted HR 3.2; 95% CI 1.2 to 9.1).</p>
<p>Conclusions Good clinical outcomes in HIV-infected children on ART are possible in a rural, decentralised service. Few young children are on ART, highlighting the urgent need to identify HIV-exposed infants.</p>
Heat transfer to two-phase air/water mixtures flowing in small tubes with inlet disequilibrium
The cooling of gas turbine components was the subject of considerable research. The problem is difficult because the available coolant, compressor bleed air, is itself quite hot and has relatively poor thermophysical properties for a coolant. Injecting liquid water to evaporatively cool the air prior to its contact with the hot components was proposed and studied, particularly as a method of cooling for contingency power applications. Injection of a small quantity of cold liquid water into a relatively hot coolant air stream such that evaporation of the liquid is still in process when the coolant contacts the hot component was studied. No approach was found whereby heat transfer characteristics could be confidently predicted for such a case based solely on prior studies. It was not clear whether disequilibrium between phases at the inlet to the hot component section would improve cooling relative to that obtained where equilibrium was established prior to contact with the hot surface
Exploring prospects of novel drugs for tuberculosis
Tuberculosis remains a disease with an enormous impact on public health worldwide. With the continuously increasing epidemic of drug-resistant tuberculosis, new drugs are desperately needed. However, even for the treatment of drug-sensitive tuberculosis, new drugs are required to shorten the treatment duration and thereby prevent development of drug resistance. Within the past ten years, major advances in tuberculosis drug research have been made, leading to a considerable number of antimycobacterial compounds which are now in the pipeline. Here we discuss a number of these novel promising tuberculosis drugs, as well as the discovery of two new potential drug targets for the development of novel effective drugs to curb the tuberculosis pandemic, ie, the coronin 1 and protein kinase G pathways. Protein kinase G is secreted by mycobacteria and is responsible for blocking lysosomal delivery within the macrophage. Coronin 1 is responsible for activating the phosphatase, calcineurin, and thereby preventing phagosome-lysosome fusion within the macrophage. Blocking these two pathways may lead to rapid killing of mycobacteri
The relation between bar formation, galaxy luminosity, and environment
We derive the bar fraction in three different environments ranging from the
field to Virgo and Coma clusters, covering an unprecedentedly large range of
galaxy luminosities (or, equivalently, stellar masses). We confirm that the
fraction of barred galaxies strongly depends on galaxy luminosity. We also show
that the difference between the bar fraction distributions as a function of
galaxy luminosity (and mass) in the field and Coma cluster are statistically
significant, with Virgo being an intermediate case. We interpret this result as
a variation of the effect of environment on bar formation depending on galaxy
luminosity. We speculate that brighter disk galaxies are stable enough against
interactions to keep their cold structure, thus, the interactions are able to
trigger bar formation. For fainter galaxies the interactions become strong
enough to heat up the disks inhibiting bar formation and even destroying the
disks. Finally, we point out that the controversy regarding whether the bar
fraction depends on environment could be resolved by taking into account the
different luminosity ranges of the galaxy samples studied so far.Comment: 4 pages, 2 figures. To appear in the proceedings of EWASS 2012
Special Session 4, Structure of galaxy disks shaped by secular evolution and
environmental processes, ed. P. Di Matteo and C. Jog, Memorie della Societ\`a
Astronomica Italiana Supplement Serie
Finite-size scaling of directed percolation above the upper critical dimension
We consider analytically as well as numerically the finite-size scaling
behavior in the stationary state near the non-equilibrium phase transition of
directed percolation within the mean field regime, i.e., above the upper
critical dimension. Analogous to equilibrium, usual finite-size scaling is
valid below the upper critical dimension, whereas it fails above. Performing a
momentum analysis of associated path integrals we derive modified finite-size
scaling forms of the order parameter and its higher moments. The results are
confirmed by numerical simulations of corresponding high-dimensional lattice
models.Comment: 4 pages, one figur
Performance of Hybrid NbTiN-Al Microwave Kinetic Inductance Detectors as Direct Detectors for Sub-millimeter Astronomy
In the next decades millimeter and sub-mm astronomy requires large format
imaging arrays and broad-band spectrometers to complement the high spatial and
spectral resolution of the Atacama Large Millimeter/sub-millimeter Array. The
desired sensors for these instruments should have a background limited
sensitivity and a high optical efficiency and enable arrays thousands of pixels
in size. Hybrid microwave kinetic inductance detectors consisting of NbTiN and
Al have shown to satisfy these requirements. We present the second generation
hybrid NbTiN-Al MKIDs, which are photon noise limited in both phase and
amplitude readout for loading levels fW. Thanks to the
increased responsivity, the photon noise level achieved in phase allows us to
simultaneously read out approximately 8000 pixels using state-of-the-art
electronics. In addition, the choice of superconducting materials and the use
of a Si lens in combination with a planar antenna gives these resonators the
flexibility to operate within the frequency range THz. Given
these specifications, hybrid NbTiN-Al MKIDs will enable astronomically usable
kilopixel arrays for sub-mm imaging and moderate resolution spectroscopy.Comment: 7 pages, 3 figures. Presented at SPIE Astronomical Telescopes and
Instrumentation 2014: Millimeter, Submillimeter, and Far-Infrared Detectors
and Instrumentation for Astronomy VI
Photon noise limited radiation detection with lens-antenna coupled Microwave Kinetic Inductance Detectors
Microwave Kinetic Inductance Detectors (MKIDs) have shown great potential for
sub-mm instrumentation because of the high scalability of the technology. Here
we demonstrate for the first time in the sub-mm band (0.1...2 mm) a photon
noise limited performance of a small antenna coupled MKID detector array and we
describe the relation between photon noise and MKID intrinsic
generation-recombination noise. Additionally we use the observed photon noise
to measure the optical efficiency of detectors to be 0.8+-0.2.Comment: The following article has been submitted to AP
Rangeland Leasing Markets in South Dakota
Most of the differences in leasing rates between private, tribal, and public rangelands are due to: ( 1) differences in tract characteristics (size, location, productivity); (2) management expenses associated with water development, fencing, fertilization, and weed control; and (3) differences in use rights by type of lease. Ranchers leasing private rangeland usually have a greater bundle of rights, greater management flexibility and control over the rangeland tracts, and fewer administrative difficulties than ranchers leasing public/tribal agency lands. Furthermore, management input and extent of long-term improvements are usually greater on private rangelands. Consequently, private rangeland leases usually command higher lease rates
On Critical Exponents and the Renormalization of the Coupling Constant in Growth Models with Surface Diffusion
It is shown by the method of renormalized field theory that in contrast to a
statement based on a mathematically ill-defined invariance transformation and
found in most of the recent publications on growth models with surface
diffusion, the coupling constant of these models renormalizes nontrivially.
This implies that the widely accepted supposedly exact scaling exponents are to
be corrected. A two-loop calculation shows that the corrections are small and
these exponents seem to be very good approximations.Comment: 4 pages, revtex, 2 postscript figures, to appear in Phys.Rev.Let
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