309 research outputs found
Disrupted Maturation of the Microbiota and Metabolome among Extremely Preterm Infants with Postnatal Growth Failure
Growth failure during infancy is a major global problem that has adverse effects on long-term health and neurodevelopment. Preterm infants are disproportionately affected by growth failure and its effects. Herein we found that extremely preterm infants with postnatal growth failure have disrupted maturation of the intestinal microbiota, characterized by persistently low diversity, dominance of pathogenic bacteria within the Enterobacteriaceae family, and a paucity of strictly anaerobic taxa including Veillonella relative to infants with appropriate postnatal growth. Metabolomic profiling of infants with growth failure demonstrated elevated serum acylcarnitines, fatty acids, and other byproducts of lipolysis and fatty acid oxidation. Machine learning algorithms for normal maturation of the microbiota and metabolome among infants with appropriate growth revealed a pattern of delayed maturation of the microbiota and metabolome among infants with growth failure. Collectively, we identified novel microbial and metabolic features of growth failure in preterm infants and potentially modifiable targets for intervention
Photospheric Abundances of the Hot Stars in NGC1399 and Limits on the Fornax Cluster Cooling Flow
We present far-UV spectroscopy of the giant elliptical galaxy NGC 1399,
obtained with the Far Ultraviolet Spectroscopic Explorer. Of all quiescent
ellipticals, NGC 1399 has the strongest known ``UV upturn'' -- a sharp spectral
rise shortward of 2500 A. It is now well-established that this emission comes
from hot horizontal branch (HB) stars and their progeny; however, the chemical
composition of these stars has been the subject of a long-standing debate. For
the first time in observations of any elliptical galaxy, our spectra clearly
show photospheric metallic absorption lines within the UV upturn. The abundance
of N is at 45% solar, Si is at 13% solar, and C is at 2% solar. Such abundance
anomalies are a natural consequence of gravitational diffusion. These
photospheric abundances fall in the range observed for subdwarf B stars of the
Galactic field.
Although NGC1399 is at the center of the Fornax cluster, we find no evidence
for O VI cooling flow emission. The upper limit to 1032,1038 emission is
3.9E-15 erg/s/cm2, equivalent to 0.14 M_sun/yr, and less than that predicted by
simple cooling flow models of the NGC 1399 X-ray luminosity.Comment: 4 pages, Latex. 2 figures. Uses corrected version of emulateapj.sty
and apjfonts.sty (included). Accepted for publication in ApJ Letters. Revised
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Stop with the FLO: using text messaging to improve retention rates in university students
Student attrition rates in undergraduate programmes are unacceptably high. The study undertaken evaluated the use of ‘FLO’, a mobile phone automated text messaging service, designed to provide information, support and reassurance in order to help alleviate the stress and anxieties that some new undergraduate students experience during the early phase of their studies. The objectives of the study were to evaluate how use of automated mobile phone texts using a system known as FLO could usefully supplement the pastoral support currently offered to new undergraduate students. A qualitative and quantitative evaluation was conducted using an open-ended questionnaire designed specifically for the study. The sample were 39 first year, undergraduate, Level 4 students from Social Welfare Law (n=16) and Sport and Exercise (n=23) who signed up to receive texts from FLO. The questionnaire was administered in a classroom situation one week after use of FLO had ceased. Data were analysed through use of a descriptive statistics and thematic analysis. Thirty nine students signed up to receive texts from FLO and 25 (64%) completed the Qualtrics questionnaire. Largely positive findings predominated including that text messages increased a sense of belonging to the University and helped students to stay on the course. It is concluded that FLO or use of similar mobile phone protocols may be a useful addition to approaches to improve undergraduate student retention rates
Constraining stellar assembly and AGN feedback at the peak epoch of star formation
We study stellar assembly and feedback from active galactic nuclei (AGN)
around the epoch of peak star formation (1<z<2), by comparing hydrodynamic
simulations to rest-frame UV-optical galaxy colours from the Wide Field Camera
3 (WFC3) Early-Release Science (ERS) Programme. Our Adaptive Mesh Refinement
simulations include metal-dependent radiative cooling, star formation, kinetic
outflows due to supernova explosions, and feedback from supermassive black
holes. Our model assumes that when gas accretes onto black holes, a fraction of
the energy is used to form either thermal winds or sub-relativistic
momentum-imparting collimated jets, depending on the accretion rate. We find
that the predicted rest-frame UV-optical colours of galaxies in the model that
includes AGN feedback is in broad agreement with the observed colours of the
WFC3 ERS sample at 1<z<2. The predicted number of massive galaxies also matches
well with observations in this redshift range. However, the massive galaxies
are predicted to show higher levels of residual star formation activity than
the observational estimates, suggesting the need for further suppression of
star formation without significantly altering the stellar mass function. We
discuss possible improvements, involving faster stellar assembly through
enhanced star formation during galaxy mergers while star formation at the peak
epoch is still modulated by the AGN feedback.Comment: 6 pages, 4 figures, accepted for publication in MNRAS Letter
Selected nucleon form factors and a composite scalar diquark
A covariant, composite scalar diquark, Fadde'ev amplitude model for the
nucleon is used to calculate pseudoscalar, isoscalar- and isovector-vector,
axial-vector and scalar nucleon form factors. The last yields the nucleon
sigma-term and on-shell sigma-nucleon coupling. The calculated form factors are
soft, and the couplings are generally in good agreement with experiment and
other determinations. Elements in the dressed-quark-axial-vector vertex that
are not constrained by the Ward-Takahashi identity contribute ~20% to the
magnitude of g_A. The calculation of the nucleon sigma-term elucidates the only
unambiguous means of extrapolating meson-nucleon couplings off the meson
mass-shell.Comment: 12 pages, REVTEX, 5 figures, epsfi
Enhanced Direct CP Violation in
We study direct CP violation in the hadronic decay , including the effect of mixing. We find
that the CP violating asymmetry is strongly dependent on the CKM matrix
elements, especially the Wolfenstein parameter . For fixed (the
effective parameter associated with factorization), the CP violating asymmetry,
, has a maximum of order when the invariant mass of the
pair is in the vicinity of the resonance. The
sensitivity of the asymmetry, , to is small. Moreover, if is
constrained using the latest experimental branching ratios from the CLEO
collaboration, we find that the sign of is always positive. Thus,
a measurement of direct CP violation in would
remove the mod ambiguity in .Comment: 37 pages, 7 figure
Professionalism and Evolving Concepts of Quality
For much of the twentieth century, quality of care was defined specifically in terms of physician characteristics and behaviors. High-quality physicians were well trained, knowledgeable, skillful, and compassionate. More recently, quality of care has been defined in terms of systems of care. High-quality organizations develop and adopt practices to reduce adverse events and optimize outcomes. This essay discusses this transformation from physician-based to organization-based concepts of quality and the consequences for patient care and medical professionalism
Multi-parallel qPCR provides increased sensitivity and diagnostic breadth for gastrointestinal parasites of humans: field-based inferences on the impact of mass deworming
BACKGROUND: Although chronic morbidity in humans from soil transmitted helminth (STH) infections can be reduced by anthelmintic treatment, inconsistent diagnostic tools make it difficult to reliably measure the impact of deworming programs and often miss light helminth infections. METHODS: Cryopreserved stool samples from 796 people (aged 2-81 years) in four villages in Bungoma County, western Kenya, were assessed using multi-parallel qPCR for 8 parasites and compared to point-of-contact assessments of the same stools by the 2-stool 2-slide Kato-Katz (KK) method. All subjects were treated with albendazole and all Ascaris lumbricoides expelled post-treatment were collected. Three months later, samples from 633 of these people were re-assessed by both qPCR and KK, re-treated with albendazole and the expelled worms collected. RESULTS: Baseline prevalence by qPCR (n = 796) was 17 % for A. lumbricoides, 18 % for Necator americanus, 41 % for Giardia lamblia and 15% for Entamoeba histolytica. The prevalence was <1% for Trichuris trichiura, Ancylostoma duodenale, Strongyloides stercoralis and Cryptosporidium parvum. The sensitivity of qPCR was 98% for A. lumbricoides and N. americanus, whereas KK sensitivity was 70% and 32%, respectively. Furthermore, qPCR detected infections with T. trichiura and S. stercoralis that were missed by KK, and infections with G. lamblia and E. histolytica that cannot be detected by KK. Infection intensities measured by qPCR and by KK were correlated for A. lumbricoides (r = 0.83, p < 0.0001) and N. americanus (r = 0.55, p < 0.0001). The number of A. lumbricoides worms expelled was correlated (p < 0.0001) with both the KK (r = 0.63) and qPCR intensity measurements (r = 0.60). CONCLUSIONS: KK may be an inadequate tool for stool-based surveillance in areas where hookworm or Strongyloides are common or where intensity of helminth infection is low after repeated rounds of chemotherapy. Because deworming programs need to distinguish between populations where parasitic infection is controlled and those where further treatment is required, multi-parallel qPCR (or similar high throughput molecular diagnostics) may provide new and important diagnostic information
Newborn spheroids at high redshift: when and how did the dominant, old stars in today's massive galaxies form?
We study ~330 massive (M* > 10^9.5 MSun), newborn spheroidal galaxies (SGs)
around the epoch of peak star formation (1<z<3), to explore the high-redshift
origin of SGs and gain insight into when and how the old stellar populations
that dominate today's Universe formed. The sample is drawn from the HST/WFC3
Early-Release Science programme, which provides deep 10-filter (0.2 - 1.7
micron) HST imaging over a third of the GOODS-South field. We find that the
star formation episodes that built the SGs likely peaked in the redshift range
2<z<5 (with a median of z~3) and have decay timescales shorter than ~1.5 Gyr.
Starburst timescales and ages show no trend with stellar mass in the range
10^9.5 < M* < 10^10.5 MSun. However, the timescales show increased scatter
towards lower values ( 10^10.5 MSun, and an age trend becomes
evident in this mass regime: SGs with M* > 10^11.5 MSun are ~2 Gyrs older than
their counterparts with M* < 10^10.5 MSun. Nevertheless, a smooth downsizing
trend with galaxy mass is not observed, and the large scatter in starburst ages
indicate that SGs are not a particularly coeval population. Around half of the
blue SGs appear not to drive their star formation via major mergers, and those
that have experienced a recent major merger, show only modest enhancements
(~40%) in their specific star formation rates. Our empirical study indicates
that processes other than major mergers (e.g. violent disk instability driven
by cold streams and/or minor mergers) likely play a dominant role in building
SGs, and creating a significant fraction of the old stellar populations that
dominate today's Universe.Comment: MNRAS in pres
Synthesizing qualitative and quantitative evidence on non-financial access barriers: implications for assessment at the district level
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