1,211 research outputs found
The African Hospitalist Fellowship
The African Paediatric Fellowship Programme is rolling out a training course for newly qualified paediatricians to equip them with the leadership skills to function in complex general paediatric settings. The care of children in Africa carries its own unique demands, from the layering effects of multiple conditions through to establishing and sustaining services under severe resource constraints. This novel training concept aims to strengthen confidence and knowledge in areas that are not priorities during standard general paediatric training. The skills gained are considered of great relevance in assisting general paediatricians to achieve their full potential in their careers
Assumptions of the primordial spectrum and cosmological parameter estimation
The observables of the perturbed universe, CMB anisotropy and large
structures, depend on a set of cosmological parameters, as well as, the assumed
nature of primordial perturbations. In particular, the shape of the primordial
power spectrum (PPS) is, at best, a well motivated assumption. It is known that
the assumed functional form of the PPS in cosmological parameter estimation can
affect the best fit parameters and their relative confidence limits. In this
paper, we demonstrate that a specific assumed form actually drives the best fit
parameters into distinct basins of likelihood in the space of cosmological
parameters where the likelihood resists improvement via modifications to the
PPS. The regions where considerably better likelihoods are obtained allowing
free form PPS lie outside these basins. In the absence of a preferred model of
inflation, this raises a concern that current cosmological parameters estimates
are strongly prejudiced by the assumed form of PPS. Our results strongly
motivate approaches toward simultaneous estimation of the cosmological
parameters and the shape of the primordial spectrum from upcoming cosmological
data. It is equally important for theorists to keep an open mind towards early
universe scenarios that produce features in the PPS.Comment: 11 pages, 2 figures, discussions extended, main results unchanged,
matches published versio
Integrated care for childhood epilepsy: ongoing challenges and lessons for other long-term conditions
Epilepsy care has been identified as a major global issue – and there are many recognised concerns in the UK for children and young people with the condition. A proposed new model could help to increase multi-sector integration, facilitate better outcomes, and offer lessons for improving care of other long-term conditions
Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectra
We present the temperature and polarization angular power spectra of the
cosmic microwave background (CMB) derived from the first 5 years of WMAP data.
The 5-year temperature (TT) spectrum is cosmic variance limited up to multipole
l=530, and individual l-modes have S/N>1 for l<920. The best fitting
six-parameter LambdaCDM model has a reduced chi^2 for l=33-1000 of
chi^2/nu=1.06, with a probability to exceed of 9.3%. There is now significantly
improved data near the third peak which leads to improved cosmological
constraints. The temperature-polarization correlation (TE) is seen with high
significance. After accounting for foreground emission, the low-l reionization
feature in the EE power spectrum is preferred by \Delta\chi^2=19.6 for optical
depth tau=0.089 by the EE data alone, and is now largely cosmic variance
limited for l=2-6. There is no evidence for cosmic signal in the BB, TB, or EB
spectra after accounting for foreground emission. We find that, when averaged
over l=2-6, l(l+1)C^{BB}_l/2\pi < 0.15 uK^2 (95% CL).Comment: 29 pages, 13 figures, accepted by ApJ
Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
We present cosmological parameter constraints based on the final nine-year
WMAP data, in conjunction with additional cosmological data sets. The WMAP data
alone, and in combination, continue to be remarkably well fit by a
six-parameter LCDM model. When WMAP data are combined with measurements of the
high-l CMB anisotropy, the BAO scale, and the Hubble constant, the densities,
Omegabh2, Omegach2, and Omega_L, are each determined to a precision of ~1.5%.
The amplitude of the primordial spectrum is measured to within 3%, and there is
now evidence for a tilt in the primordial spectrum at the 5sigma level,
confirming the first detection of tilt based on the five-year WMAP data. At the
end of the WMAP mission, the nine-year data decrease the allowable volume of
the six-dimensional LCDM parameter space by a factor of 68,000 relative to
pre-WMAP measurements. We investigate a number of data combinations and show
that their LCDM parameter fits are consistent. New limits on deviations from
the six-parameter model are presented, for example: the fractional contribution
of tensor modes is limited to r<0.13 (95% CL); the spatial curvature parameter
is limited to -0.0027 (+0.0039/-0.0038); the summed mass of neutrinos is <0.44
eV (95% CL); and the number of relativistic species is found to be 3.84+/-0.40
when the full data are analyzed. The joint constraint on Neff and the
primordial helium abundance agrees with the prediction of standard Big Bang
nucleosynthesis. We compare recent PLANCK measurements of the
Sunyaev-Zel'dovich effect with our seven-year measurements, and show their
mutual agreement. Our analysis of the polarization pattern around temperature
extrema is updated. This confirms a fundamental prediction of the standard
cosmological model and provides a striking illustration of acoustic
oscillations and adiabatic initial conditions in the early universe.Comment: 32 pages, 12 figures, v3: Version accepted to Astrophysical Journal
Supplement Series. Includes improvements in response to referee and
community; corrected 3 entries in Table 10, (w0 & wa model). See the Legacy
Archive for Microwave Background Data Analysis (LAMBDA):
http://lambda.gsfc.nasa.gov/product/map/current/ for further detai
The Wilkinson Microwave Anisotropy Probe (WMAP) Source Catalog
We present the list of point sources found in the WMAP 5-year maps. The
technique used in the first-year and three-year analysis now finds 390 point
sources, and the five-year source catalog is complete for regions of the sky
away from the galactic plane to a 2 Jy limit, with SNR > 4.7 in all bands in
the least covered parts of the sky. The noise at high frequencies is still
mainly radiometer noise, but at low frequencies the CMB anisotropy is the
largest uncertainty. A separate search of CMB-free V-W maps finds 99 sources of
which all but one can be identified with known radio sources. The sources seen
by WMAP are not strongly polarized. Many of the WMAP sources show significant
variability from year to year, with more than a 2:1 range between the minimum
and maximum fluxes.Comment: 31 pages Latex with 4 embedded figures. Version accepted by the ApJ
Supplement
Primary membranous glomerulonephritis with negative serum PLA2R in haemophilia : a successfully managed with rituximab : case report and review of the literature
Background: Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) cause a wide range of glomerular pathologies. In people with haemophilia, transfusion-associated infections with these viruses are common and definitive pathological diagnosis in this population is complicated by the difficulty of safely obtaining a renal biopsy. Membranous nephropathy (MN) is a common cause of adult onset nephrotic syndrome occurring in both primary and secondary forms. Primary MN is associated with podocyte autoantibodies, predominantly against phospholipase A2 receptor (PLA2R). Secondary disease is often associated with viral infection; however, infrequently with HIV or HCV. Distinguishing these entities from each other and other viral glomerular disease is vital as treatment strategies are disparate. Case presentation: We present the case of a 48-year-old man with moderate haemophilia A and well-controlled transfusion-associated HCV and HIV coinfection who presented with sudden onset nephrotic range proteinuria. Renal biopsy demonstrated grade two membranous nephropathy with associated negative serum PLA2R testing. Light and electron microscopic appearances were indeterminant of a primary or secondary cause. Given his extremely stable co-morbidities, treatment with rituximab and subsequent angiotensin receptor blockade was initiated for suspected primary MN and the patient had sustained resolution in proteinuria over the following 18 months. Subsequent testing demonstrated PLA2R positive glomerular immunohistochemistry despite multiple negative serum results. Conclusions: Pursuing histological diagnosis is important in complex cases of MN as the treatment strategies between primary and secondary vary significantly. Serum PLA2R testing alone may be insufficient in the presence of multiple potential causes of secondary MN
Seven-year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Foreground Emission
We present updated estimates of Galactic foreground emission using seven years of WMAP data. Using the power
spectrum of differences between multi-frequency template-cleaned maps, we find no evidence for foreground
contamination outside of the updated (KQ85y7) foreground mask.We place a 15μK upper bound on rms foreground
contamination in the cleaned maps used for cosmological analysis. Further, the cleaning process requires only three
power-law foregrounds outside of the mask. We find no evidence for polarized foregrounds beyond those from soft
(steep-spectrum) synchrotron and thermal dust emission; in particular we find no indication in the polarization data
of an extra “haze” of hard synchrotron emission from energetic electrons near the Galactic center. We provide an
updated map of the cosmic microwave background (CMB) using the internal linear combination method, updated
foreground masks, and updates to point source catalogs using two different techniques. With additional years of
data, we now detect 471 point sources using a five-band technique and 417 sources using a three-band CMB-free
technique. In total there are 62 newly detected point sources, a 12% increase over the five-year release. Also new
are tests of theMarkov chain Monte Carlo foreground fitting procedure against systematics in the time-stream data,
and tests against the observed beam asymmetry. Within a few degrees of the Galactic plane, the behavior in total
intensity of low-frequency foregrounds is complicated and not completely understood. WMAP data show a rapidly
steepening spectrum from 20 to 40 GHz, which may be due to emission from spinning dust grains, steepening
synchrotron, or other effects. Comparisons are made to a 1 deg 408 MHz map (Haslam et al.) and the 11 deg
ARCADE 2 data (Singal et al.).We find that spinning dust or steepening synchrotron models fit the combination of
WMAP and 408 MHz data equally well. ARCADE data appear inconsistent with the steepening synchrotron model
and consistent with the spinning dust model, though some discrepancies remain regarding the relative strength
of spinning dust emission. More high-resolution data in the 10–40 GHz range would shed much light on these
issues
Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
We present new full-sky temperature and polarization maps in five frequency
bands from 23 to 94 GHz, based on data from the first five years of the WMAP
sky survey. The five-year maps incorporate several improvements in data
processing made possible by the additional years of data and by a more complete
analysis of the instrument calibration and in-flight beam response. We present
several new tests for systematic errors in the polarization data and conclude
that Ka band data (33 GHz) is suitable for use in cosmological analysis, after
foreground cleaning. This significantly reduces the overall polarization
uncertainty. With the 5 year WMAP data, we detect no convincing deviations from
the minimal 6-parameter LCDM model: a flat universe dominated by a cosmological
constant, with adiabatic and nearly scale-invariant Gaussian fluctuations.
Using WMAP data combined with measurements of Type Ia supernovae and Baryon
Acoustic Oscillations, we find (68% CL uncertainties): Omega_bh^2 = 0.02267 \pm
0.00059, Omega_ch^2 = 0.1131 \pm 0.0034, Omega_Lambda = 0.726 \pm 0.015, n_s =
0.960 \pm 0.013, tau = 0.084 \pm 0.016, and Delta_R^2 = (2.445 \pm 0.096) x
10^-9. From these we derive: sigma_8 = 0.812 \pm 0.026, H_0 = 70.5 \pm 1.3
km/s/Mpc, z_{reion} = 10.9 \pm 1.4, and t_0 = 13.72 \pm 0.12 Gyr. The new limit
on the tensor-to-scalar ratio is r < 0.22 (95% CL). We obtain tight,
simultaneous limits on the (constant) dark energy equation of state and spatial
curvature: -0.14 < 1+w < 0.12 and -0.0179 < Omega_k < 0.0081 (both 95% CL). The
number of relativistic degrees of freedom (e.g. neutrinos) is found to be
N_{eff} = 4.4 \pm 1.5, consistent with the standard value of 3.04. Models with
N_{eff} = 0 are disfavored at >99.5% confidence.Comment: 46 pages, 13 figures, and 7 tables. Version accepted for publication,
ApJS, Feb-2009. Includes 5-year dipole results and additional references.
Also available at
http://lambda.gsfc.nasa.gov/product/map/dr3/map_bibliography.cf
CMBPol Mission Concept Study: Prospects for polarized foreground removal
In this report we discuss the impact of polarized foregrounds on a future
CMBPol satellite mission. We review our current knowledge of Galactic polarized
emission at microwave frequencies, including synchrotron and thermal dust
emission. We use existing data and our understanding of the physical behavior
of the sources of foreground emission to generate sky templates, and start to
assess how well primordial gravitational wave signals can be separated from
foreground contaminants for a CMBPol mission. At the estimated foreground
minimum of ~100 GHz, the polarized foregrounds are expected to be lower than a
primordial polarization signal with tensor-to-scalar ratio r=0.01, in a small
patch (~1%) of the sky known to have low Galactic emission. Over 75% of the sky
we expect the foreground amplitude to exceed the primordial signal by about a
factor of eight at the foreground minimum and on scales of two degrees. Only on
the largest scales does the polarized foreground amplitude exceed the
primordial signal by a larger factor of about 20. The prospects for detecting
an r=0.01 signal including degree-scale measurements appear promising, with 5
sigma_r ~0.003 forecast from multiple methods. A mission that observes a range
of scales offers better prospects from the foregrounds perspective than one
targeting only the lowest few multipoles. We begin to explore how optimizing
the composition of frequency channels in the focal plane can maximize our
ability to perform component separation, with a range of typically 40 < nu <
300 GHz preferred for ten channels. Foreground cleaning methods are already in
place to tackle a CMBPol mission data set, and further investigation of the
optimization and detectability of the primordial signal will be useful for
mission design.Comment: 42 pages, 14 figures, Foreground Removal Working Group contribution
to the CMBPol Mission Concept Study, v2, matches AIP versio
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