1,721 research outputs found
Transverse and longitudinal correlation functions in the Intergalactic Medium from 32 close pairs of high-redshift quasars
We present the transverse flux correlation function of the Lyman-alpha forest
in quasar absorption spectra at z~2.1 from VLT-FORS and VLT-UVES observations
of a total of 32 pairs of quasars; 26 pairs with separations in the range
0.6<theta<4 arcmin and 6 pairs with 4<theta<10 arcmin. Correlation is detected
at the 3sigma level up to separations of the order of ~4 arcmin (or ~4.4 h^{-1}
Mpc comoving at z=2.1 for Omega_{m}=0.3 and Omega_{Lambda}=0.7). We have,
furthermore, measured the longitudinal correlation function at a somewhat
higher mean redshift (z=2.39) from 20 lines of sight observed with high
spectral resolution and high signal-to-noise ratio with VLT-UVES. We compare
the observed transverse and longitudinal correlation functions to that obtained
from numerical simulations and illustrate the effect of spectral resolution,
thermal broadening and peculiar motions. The shape and correlation length of
the correlation functions are in good agreement with those expected from
absorption by the filamentary and sheet-like structures in the photoionized
warm intergalactic medium predicted in CDM-like models for structures
formation. Using a sample of 139 C_{iv} systems detected along the lines of
sight toward the pairs of quasars we also investigate the transverse
correlation of metals on the same scales. The observed transverse correlation
function of intervening C_{iv} absorption systems is consistent with that of a
randomly distributed population of absorbers. This is likely due to the small
number of pairs with separation less than 2 arcmin. We detect, however, a
significant overdensity of systems in the sightlines towards the quartet
Q0103-294A&B, Q0102-2931 and Q0102-293 which extends over the redshift range
1.5<z<2.2 and an angular scale larger than 10 arcmin.Comment: accepted for publication in MNRAS, Appendix B and C will be published
online onl
Physical properties and small-scale structure of the Lyman-alpha forest: Inversion of the HE 1122-1628 UVES spectrum
We study the physical properties of the Lyman-alpha forest by applying the
inversion method described by Pichon et al. (2001) to the high resolution and
high S/N ratio spectrum of the z_em=2.40 quasar HE 1122-1628 obtained during
Science Verification of UVES at the VLT. We compare the column densities
obtained with the new fitting procedure with those derived using standard Voigt
profile methods. The agreement is good and gives confidence in the new
description of the Lyman-alpha forest as a continuous field as derived from our
method. We show that the observed number density of lines with logN>13 and 14
is, respectively, 50 and 250 per unit redshift at z~2. We study the physical
state of the gas, neglecting peculiar velocities, assuming a relation between
the overdensity and the temperature. T=Tbar * rho^(2beta). There is an
intrinsic degeneracy between the parameters beta and Tbar. We demonstrate that,
at a fixed beta, the temperature at mean density, Tbar, can be uniquely
extracted however. While applying the method to HE 1122-1628, we conclude that
for 0.2<beta<0.3, 6000<Tbar<15000 K at z~2. We investigate the small scale
structure of strong absorption lines using the information derived from the
Lyman-beta, Lyman-gamma and Civ profiles. Introducing the Lyman-beta line in
the fit allows us to reconstruct the density field up to rho~10 instead of 5
for the Lyman-alpha line only. There may be small velocity shifts ~10km.s^{-1}
between the peaks in the Civ and Hi density profiles. Although the statistics
is small, it seems that Civ/Hi and n_HI are anti-correlated. This could be a
consequence of the high sensitivity of the Civ/Hi ratio to temperature. The
presence of associated Ovi absorption, with similar profile, confirms that the
gas is photo-ionized and at a temperature of T~10^5 K.Comment: 15 pages, 21 figures, accepted for publication in A&A. Quoted results
from other papers in section 4.2 have been modifie
Hsp70 and Hsp40 inhibit an inter-domain interaction necessary for transcriptional activity in the androgen receptor.
Molecular chaperones such as Hsp40 and Hsp70 hold the androgen receptor (AR) in an inactive conformation. They are released in the presence of androgens, enabling transactivation and causing the receptor to become aggregation-prone. Here we show that these molecular chaperones recognize a region of the AR N-terminal domain (NTD), including a FQNLF motif, that interacts with the AR ligand-binding domain (LBD) upon activation. This suggests that competition between molecular chaperones and the LBD for the FQNLF motif regulates AR activation. We also show that, while the free NTD oligomerizes, binding to Hsp70 increases its solubility. Stabilizing the NTD-Hsp70 interaction with small molecules reduces AR aggregation and promotes its degradation in cellular and mouse models of the neuromuscular disorder spinal bulbar muscular atrophy. These results help resolve the mechanisms by which molecular chaperones regulate the balance between AR aggregation, activation and quality control
Importance of triggers and veto-barriers for the implementation of sanitation in informal peri-urban settlements – The case of cochabamba, Bolivia
An estimated 2.4 billion people lack access to improved sanitation which has devastating consequences for human health and the environment. Understanding what constitute sanitation demand is crucial for accelerating the spread of improved sanitation. This study aims to understand the adoption mechanisms for improved sanitation. An informal peri-urban settlement in Cochabamba, Bolivia was selected as a case study to understand adoption patterns. Various qualitative methods of data collection and analysis were employed. The findings showed that pour-flush toilets was the only preferred sanitation alternative at the study site. An adoption framework for waterborne toilets was developed based on diffusion of innovation theory. Factors that influence adoption were identified. Some functioned as triggers and initiated adoption, whereas some factors blocked adoption and constituted veto-barriers. Most factors were connected to the individual household situation and its members, but neighborhood development also affected pour-flush adoption. Based on adoption time the residents were divided into the following adoption groups: first adopters, early majority, late majority, laggards and non-adopters. Each adoption group followed its own adoption route with specific characteristics and respective triggers or veto-barriers. We argue that the strong demand for waterborne toilets in peri-urban areas need to be recognized and the developed framework could be used for customizing sanitation improvement programs for certain target groups
Limited role of spatial selfstructuring in emergent trade-offs during pathogen evolution
Pathogen transmission and virulence are main evolutionary variables broadly assumed to be linked
through trade-offs. In well-mixed populations, these trade-offs are often ascribed to physiological
restrictions, while populations with spatial self-structuring might evolve emergent trade-offs. Here,
we reexamine a spatially-explicit, SIR model of the latter kind proposed by Ballegooijen and Boerlijst
with the aim of characterising the mechanisms causing the emergence of the trade-off and its structural
robustness. Using invadability criteria, we establish the conditions under which an evolutionary
feedback between transmission and virulence mediated by pattern formation can poise the system to
a critical boundary separating a disordered state (without emergent trade-off) from a self-structured
phase (where the trade-off emerges), and analytically calculate the functional shape of the boundary
in a certain approximation. Beyond evolutionary parameters, the success of an invasion depends
on the size and spatial structure of the invading and invaded populations. Spatial self-structuring is
often destroyed when hosts are mobile, changing the evolutionary dynamics to those of a well-mixed
population. In a metapopulation scenario, the systematic extinction of the pathogen in the disordered
phase may counteract the disruptive effect of host mobility, favour pattern formation and therefore
recover the emergent trade-off.This work has been supported by the Spanish Ministerio de Economía, Industria y Competitividad and FEDER
funds of the EU through grants ViralESS (FIS2014-57686-P and FIS2017-84256-P). The internship of VB was
financed by the Severo Ochoa Centers of Excellence Program (SEV-2013-0347)
Enteric Neurospheres Are Not Specific to Neural Crest Cultures: Implications for Neural Stem Cell Therapies
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited
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Author Correction: Hsp70 and Hsp40 inhibit an inter-domain interaction necessary for transcriptional activity in the androgen receptor.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
Whole body vibration compared to conventional physiotherapy in patients with gonarthrosis: a protocol for a randomized, controlled study
<p>Abstract</p> <p>Background</p> <p>Osteoarthritis (OA) is the most common degenerative arthropathy. Load-bearing joints such as knee and hip are more often affected than spine or hands. The prevalence of gonarthrosis is generally higher than that of coxarthrosis.</p> <p>Because no cure for OA exists, the main emphasis of therapy is analgesic treatment through either mobility or medication. Non-pharmacologic treatment is the first step, followed by the addition of analgesic medication, and ultimately by surgery.</p> <p>The goal of non-pharmacologic and non-invasive therapy is to improve neuromuscular function, which in turn both prevents formation of and delays progression of OA. A modification of conventional physiotherapy, whole body vibration has been successfully employed for several years. Since its introduction, this therapy is in wide use at our facility not only for gonarthrosis, but also coxarthrosis and other diseases leading to muscular imbalance.</p> <p>Methods/Design</p> <p>This study is a randomized, therapy-controlled trial in a primary care setting at a university hospital. Patients presenting to our outpatient clinic with initial symptoms of gonarthrosis will be assessed against inclusion and exclusion criteria. After patient consent, 6 weeks of treatment will ensue. During the six weeks of treatment, patients will receive one of two treatments, conventional physiotherapy or whole-body-vibration exercises of one hour three times a week. Follow-up examinations will be performed immediately after treatment and after another 6 and 20 weeks, for a total study duration of 6 months. 20 patients will be included in each therapy group.</p> <p>Outcome measurements will include objective analysis of motion and ambulation as well as examinations of balance and isokinetic force. The Western Ontario and McMaster Universities Arthritis Index and SF-12 scores, the patients' overall status, and clinical examinations of the affected joint will be carried out.</p> <p>Discussion</p> <p>As new physiotherapy techniques develop for the treatment of OA, it is important to investigate the effectiveness of competing strategies. With this study, not only patient-based scores, but also objective assessments will be used to quantify patient-derived benefits of therapy.</p> <p>Trial registration</p> <p>Deutsches Register Klinischer Studien (DRKS) DRKS00000415</p> <p>Clinicaltrials.gov NCT01037972</p> <p>EudraCT 2009-017617-29</p
Response of symptom dimensions in obsessive-compulsive disorder to treatment with citalopram or placebo
Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.
OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
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