716 research outputs found
Environmental enteric dysfunction and the fecal microbiota in malawian children
Environmental enteric dysfunction (EED) is often measured with a dual sugar absorption test and implicated as a causative factor in childhood stunting. Disturbances in the gut microbiota are hypothesized to be a mechanism by which EED is exacerbated, although this supposition lacks support. We performed 16S ribosomal RNA gene sequencing of fecal samples from 81 rural Malawian children with varying degrees of EED to determine which bacterial taxa were associated with EED. At the phyla level, Proteobacteria abundance is reduced with severe EED. Among bacterial genera, Megasphaera, Mitsuokella, and Sutterella were higher in EED and Succinivibrio, Klebsiella, and Clostridium_XI were lower in EED. Bacterial diversity did not vary with the extent of EED. Though EED is a condition that is typically believed to affect the proximal small bowel, and our focus was on stool, our data do suggest that there are intraluminal microbial differences that reflect, or plausibly lead to, EED
Spinocerebellar ataxia types 1, 2, 3, and 6: disease severity and nonataxia symptoms.
OBJECTIVE: To identify factors that determine disease severity and clinical
phenotype of the most common spinocerebellar ataxias (SCAs), we studied 526
patients with SCA1, SCA2, SCA3. or SCA6.
METHODS: To measure the severity of ataxia we used the Scale for the Assessment
and Rating of Ataxia (SARA). In addition, nonataxia symptoms were assessed with
the Inventory of Non-Ataxia Symptoms (INAS). The INAS count denotes the number of
nonataxia symptoms in each patient.
RESULTS: An analysis of covariance with SARA score as dependent variable and
repeat lengths of the expanded and normal allele, age at onset, and disease
duration as independent variables led to multivariate models that explained 60.4%
of the SARA score variance in SCA1, 45.4% in SCA2, 46.8% in SCA3, and 33.7% in
SCA6. In SCA1, SCA2, and SCA3, SARA was mainly determined by repeat length of the
expanded allele, age at onset, and disease duration. The only factors determining
the SARA score in SCA6 were age at onset and disease duration. The INAS count was
5.0 +/- 2.3 in SCA1, 4.6 +/- 2.2 in SCA2, 5.2 +/- 2.5 in SCA3, and 2.0 +/- 1.7 in
SCA6. In SCA1, SCA2, and SCA3, SARA score and disease duration were the strongest
predictors of the INAS count. In SCA6, only age at onset and disease duration had
an effect on the INAS count.
CONCLUSIONS: Our study suggests that spinocerebellar ataxia (SCA) 1, SCA2, and
SCA3 share a number of common biologic properties, whereas SCA6 is distinct in
that its phenotype is more determined by age than by disease-related factors
Signal yields, energy resolution, and recombination fluctuations in liquid xenon
This work presents an analysis of monoenergetic electronic recoil peaks in
the dark-matter-search and calibration data from the first underground science
run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and
light yields for electronic recoil energies between 5.2 and 661.7 keV are
measured, as well as the energy resolution for the LUX detector at those same
energies. Additionally, there is an interpretation of existing measurements and
descriptions of electron-ion recombination fluctuations in liquid xenon as
limiting cases of a more general liquid xenon re- combination fluctuation
model. Measurements of the standard deviation of these fluctuations at
monoenergetic electronic recoil peaks exhibit a linear dependence on the number
of ions for energy deposits up to 661.7 keV, consistent with previous LUX
measurements between 2-16 keV with H. We highlight similarities in liquid
xenon recombination for electronic and nuclear recoils with a comparison of
recombination fluctuations measured with low-energy calibration data.Comment: 11 pages, 12 figures, 3 table
The Citation Field of Evolutionary Economics
Evolutionary economics has developed into an academic field of its own,
institutionalized around, amongst others, the Journal of Evolutionary Economics
(JEE). This paper analyzes the way and extent to which evolutionary economics
has become an interdisciplinary journal, as its aim was: a journal that is
indispensable in the exchange of expert knowledge on topics and using
approaches that relate naturally with it. Analyzing citation data for the
relevant academic field for the Journal of Evolutionary Economics, we use
insights from scientometrics and social network analysis to find that, indeed,
the JEE is a central player in this interdisciplinary field aiming mostly at
understanding technological and regional dynamics. It does not, however, link
firmly with the natural sciences (including biology) nor to management
sciences, entrepreneurship, and organization studies. Another journal that
could be perceived to have evolutionary acumen, the Journal of Economic Issues,
does relate to heterodox economics journals and is relatively more involved in
discussing issues of firm and industry organization. The JEE seems most keen to
develop theoretical insights
Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches
The LUX-ZEPLIN (LZ) experiment will search for dark matter particle
interactions with a detector containing a total of 10 tonnes of liquid xenon
within a double-vessel cryostat. The large mass and proximity of the cryostat
to the active detector volume demand the use of material with extremely low
intrinsic radioactivity. We report on the radioassay campaign conducted to
identify suitable metals, the determination of factors limiting radiopure
production, and the selection of titanium for construction of the LZ cryostat
and other detector components. This titanium has been measured with activities
of U~1.6~mBq/kg, U~0.09~mBq/kg,
Th~~mBq/kg, Th~~mBq/kg, K~0.54~mBq/kg, and Co~0.02~mBq/kg (68\% CL).
Such low intrinsic activities, which are some of the lowest ever reported for
titanium, enable its use for future dark matter and other rare event searches.
Monte Carlo simulations have been performed to assess the expected background
contribution from the LZ cryostat with this radioactivity. In 1,000 days of
WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute
only a mean background of (stat)(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle
Physic
Canadian Arctic Tide Measurement Techniques and Results
About 10 years ago the Canadian Hydrographic Service recognized the need for a planned approach to completing tide and current surveys of the Canadian Arctic Archipelago in order to meet the requirements of marine shipping and construction industries as well as the needs of environmental studies related to resource development. Therefore, a program of tidal surveys was begun which has resulted in a data base of tidal records covering most of the Archipelago. In this paper the problems faced by tidal surveyors and others working in the harsh Arctic environment are described and the variety of equipment and techniques developed for short, medium and long-term deployments are reported. The tidal characteristics throughout the Archipelago, determined primarily from these surveys, are briefly summarized. It was also recognized that there would be a need for real time tidal data by engineers, surveyors and mariners. Since the existing permanent tide gauges in the Arctic do not have this capability, a project was started in the early 1980’s to develop and construct a new permanent gauging system. The first of these gauges was constructed during the summer of 1985 and is described
Assessing the fidelity of AOGCM-simulated relationships between large-scale modes of climate variability and wind speeds
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