7,102 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>
Agreement between methods of measurement with multiple observations per individual
Limits of agreement provide a straightforward and intuitive approach to agreement between different methods for measuring the same quantity. When pairs of observations using the two methods are independent, i.e., on different subjects, the calculations are very simple and straightforward. Some authors collect repeated data, either as repeated pairs of measurements on the same subject, whose true value of the measured quantity may be changing, or more than one measurement by one or both methods of an unchanging underlying quantity. In this paper we describe methods for analysing such clustered observations, both when the underlying quantity is assumed to be changing and when it is not
Magnetoswitching of current oscillations in diluted magnetic semiconductor nanostructures
Strongly nonlinear transport through Diluted Magnetic Semiconductor
multiquantum wells occurs due to the interplay between confinement, Coulomb and
exchange interaction. Nonlinear effects include the appearance of spin
polarized stationary states and self-sustained current oscillations as possible
stable states of the nanostructure, depending on its configuration and control
parameters such as voltage bias and level splitting due to an external magnetic
field. Oscillatory regions grow in size with well number and level splitting. A
systematic analysis of the charge and spin response to voltage and magnetic
field switching of II-VI Diluted Magnetic Semiconductor multiquantum wells is
carried out. The description of stationary and time-periodic spin polarized
states, the transitions between them and the responses to voltage or magnetic
field switching have great importance due to the potential implementation of
spintronic devices based on these nanostructures.Comment: 14 pages, 4 figures, Revtex, to appear in PR
The Taurus Tunable Filter Field Galaxy Survey: Sample Selection and Narrowband Number-Counts
Recent evidence suggests a falling volume-averaged star-formation rate (SFR)
over z ~ 1. It is not clear, however, the extent to which the selection of such
samples influences the measurement of this quantity. Using the Taurus Tunable
Filter (TTF) we have obtained an emission-line sample of faint star-forming
galaxies over comparable lookback times: the TTF Field Galaxy Survey. By
selecting through emission-lines, we are screening galaxies through a quantity
that scales directly with star-formation activity for a given choice of initial
mass function. The scanning narrowband technique furnishes a galaxy sample that
differs from traditional broadband-selected surveys in both its volume-limited
nature and selection of galaxies through emission-line flux. Three discrete
wavelength intervals are covered, centered at H-alpha redshifts z = 0.08, 0.24
and 0.39.
Galaxy characteristics are presented and comparisons made with existing
surveys of both broadband and emission-line selection. When the number-counts
of emission-line objects are compared with those expected on the basis of
existing H-alpha surveys, we find an excess of ~ 3 times at the faintest
limits. While these detections are yet to be independently confirmed,
inspection of the stronger subsample of galaxies detected in both the line and
continuum (line-on-continuum subsample; 13 %) is sufficient to support an
excess population. This increase in the emission-line field population implies
higher star-formation densities over z ~ 0.4. However, further study in the
form of multi-object spectroscopic follow-up is necessary to quantify this and
confirm the faintest detections in the sample.Comment: 48 pages, 12 figures. To appear in the Astrophysical Journal. An
abridged version of the Abstract is shown her
Taurus Tunable Filter -- seven years of observing
The Taurus Tunable Filter (TTF) has now been in regular use for seven years
on the Anglo-Australian Telescope. The instrument was also used for three years
(1996--1999) on the William Herschel Telescope. We present a brief review of
the different applications in order to illustrate the versatility of tunable
filters in optical/IR spectrophotometric imaging. Tunable filters are now
planned or are under development for 6-10m class telescopes which ensures their
use for years to come.Comment: PASA, accepted. 20 pages, 9 figure
Recommended from our members
Assessing plantar sensation in the foot using the FOot Roughness Discrimination Test (FoRDTâą): a reliability and validity study in stroke
BACKGROUND: The foot sole represents a sensory dynamometric map and is essential for balance and gait control. Sensory impairments are common, yet often difficult to quantify in neurological conditions, particularly stroke. A functionally oriented and quantifiable assessment, the Foot Roughness Discrimination Test (FoRDTâą), was developed to address these shortcomings. OBJECTIVE: To evaluate inter- and intra-rater reliability, convergent and discriminant validity of the Foot Roughness Discrimination Test (FoRDTâą). DESIGN: Test-retest design. SETTING: Hospital Outpatient. PARTICIPANTS: Thirty-two people with stroke (mean age 70) at least 3 months after stroke, and 32 healthy, age-matched controls (mean age 70). MAIN OUTCOME MEASURES: Roughness discrimination thresholds were quantified utilising acrylic foot plates, laser-cut to produce graded spatial gratings. Stroke participants were tested on three occasions, and by two different raters. Inter- and intra-rater reliability and agreement were evaluated with Intraclass Correlation Coefficients and Bland-Altman plots. Convergent validity was evaluated through Spearman rank correlation coefficients (rho) between the FoRDTâą and the Erasmus modified Nottingham Sensory Assessment (EmNSA). RESULTS: Intra- and inter rater reliability and agreement were excellent (ICC =.86 (95% CI .72-.92) and .90 (95% CI .76 -.96)). Discriminant validity was demonstrated through significant differences in FoRDTâą between stroke and control participants (p.05). CONCLUSIONS: This simple and functionally oriented test of plantar sensation is reliable, valid and clinically feasible for use in an ambulatory, chronic stroke and elderly population. It offers clinicians and researchers a sensitive and robust sensory measure and may further support the evaluation of rehabilitation targeting foot sensation. This article is protected by copyright. All rights reserved
Discovery of a 500 pc shell in the nucleus of Centaurus A
Spitzer Space Telescope mid-infrared images of the radio galaxy Centaurus A
reveal a shell-like, bipolar, structure 500 pc to the north and south of the
nucleus. This shell is seen in 5.8, 8.0 and 24 micron broad-band images. Such a
remarkable shell has not been previously detected in a radio galaxy and is the
first extragalactic nuclear shell detected at mid-infrared wavelengths. We
estimate that the shell is a few million years old and has a mass of order
million solar masses. A conservative estimate for the mechanical energy in the
wind driven bubble is 10^53 erg. The shell could have created by a small few
thousand solar mass nuclear burst of star formation. Alternatively, the
bolometric luminosity of the active nucleus is sufficiently large that it could
power the shell. Constraints on the shell's velocity are lacking. However, if
the shell is moving at 1000 km/s then the required mechanical energy would be
100 times larger.Comment: submitted to ApJ Letter
- âŠ