714 research outputs found
A survey of diffuse interstellar bands in the Andromeda galaxy: optical spectroscopy of M31 OB stars
We present the largest sample to-date of intermediate-resolution blue-to-red
optical spectra of B-type supergiants in M31 and undertake the first survey of
diffuse interstellar bands (DIBs) in this galaxy. Spectral classifications,
radial velocities and interstellar reddenings are presented for 34 stars in
three regions of M31. Radial velocities and equivalent widths are given for the
5780 and 6283 DIBs towards 11 stars. Equivalent widths are also presented for
the following DIBs detected in three sightlines in M31: 4428, 5705, 5780, 5797,
6203, 6269, 6283, 6379, 6613, 6660, and 6993. All of these M31 DIB carriers
reside in clouds at radial velocities matching those of interstellar Na I
and/or H I. The relationships between DIB equivalent widths and reddening
(E(B-V)) are consistent with those observed in the local ISM of the Milky Way.
Many of the observed sightlines show DIB strengths (per unit reddening) which
lie at the upper end of the range of Galactic values. DIB strengths per unit
reddening are found (with 68% confidence), to correlate with the interstellar
UV radiation field strength. The strongest DIBs are observed where the
interstellar UV flux is lowest. The mean Spitzer 8/24 micron emission ratio in
our three fields is slightly lower than that measured in the Milky Way, but we
identify no correlation between this ratio and the DIB strengths in M31.
Interstellar oxygen abundances derived from the spectra of three M31 H II
regions in one of the fields indicate that the average metallicity of the ISM
in that region is 12 + log[O/H] = 8.54 +- 0.18, which is approximately equal to
the value in the solar neighbourhood
Rural Teachersâ Burnout, Well-Being, and COVID-19 Related Stress During the Pandemic
To date, researchers have not explored the impact of the COVID-19 pandemic on the well-being of rural teachers specifically. Rural schools already faced long-standing issues of lower salaries, professional isolation, teacher shortages, and technology challenges, suggesting rural teachers may have experienced even higher levels of distress due to the pandemic. Overall, however, teachers from one rural county school system in the southeastern United States reported moderate COVID-19 concerns, low distress, and moderate well-being. Results could reflect responses characteristic of rural resilience. Further study is needed to explore teachersâ unique coping strategies
The Prevalence and Indications of Intravenous Rehydration Therapy in Hospital Settings: A Systematic Review
Draft genome sequence of the bacteriophage vB_Eco_slurp01.
Bacteriophage vB_Eco_slurp01 was isolated from porcine feces using Escherichia coli MG1655 as a host. With a genome size of 348 kb, vB_Eco_slurp01 is one of the largest bacteriophages isolated to date
Drimolen cranium DNH 155 documents microevolution in an early hominin species
Paranthropus robustus is a small-brained extinct hominin from South Africa characterized by derived, robust craniodental
morphology. The most complete known skull of this species is DNH 7 from Drimolen Main Quarry, which differs from
P. robustus specimens recovered elsewhere in ways attributed to sexual dimorphism. Here, we describe a new fossil specimen
from Drimolen Main Quarry, dated from approximately 2.04â1.95 million years ago, that challenges this view. DNH 155 is a
well-preserved adult male cranium that shares with DNH 7 a suite of primitive and derived features unlike those seen in adult
P. robustus specimens from other chronologically younger deposits. This refutes existing hypotheses linking sexual dimorphism,
ontogeny and social behaviour within this taxon, and clarifies hypotheses concerning hominin phylogeny. We document
small-scale morphological changes in P. robustus associated with ecological change within a short time frame and restricted
geography. This represents the most highly resolved evidence yet of microevolutionary change within an early hominin species
Leucine Biosynthesis Is Involved in Regulating High Lipid Accumulation in Yarrowia lipolytica
The yeast Yarrowia lipolytica is a potent accumulator of lipids, and lipogenesis in this organism can be influenced by a variety of factors, such as genetics and environmental conditions. Using a multifactorial study, we elucidated the effects of both genetic and environmental factors on regulation of lipogenesis in Y. lipolytica and identified how two opposite regulatory states both result in lipid accumulation. This study involved comparison of a strain overexpressing diacylglycerol acyltransferase (DGA1) with a control strain grown under either nitrogen or carbon limitation conditions. A strong correlation was observed between the responses on the transcript and protein levels. Combination of DGA1 overexpression with nitrogen limitation resulted in a high level of lipid accumulation accompanied by downregulation of several amino acid biosynthetic pathways, including that of leucine in particular, and these changes were further correlated with a decrease in metabolic fluxes. This downregulation was supported by the measured decrease in the level of 2-isopropylmalate, an intermediate of leucine biosynthesis. Combining the multi-omics data with putative transcription factor binding motifs uncovered a contradictory role for TORC1 in controlling lipid accumulation, likely mediated through 2-isopropylmalate and a Leu3-like transcription factor
Non-O157 Shiga Toxinâproducing Escherichia coli Associated with Venison
News reports of âE. coli outbreaksâ usually refer to Shiga toxinâproducing E. coli O157. But there are other types of Shiga toxinâproducing E. coli, often called STEC,about which less is known. For these other types of STEC, what is the source? What are the risk factors? An outbreak among 29 high school students in Minnesota provided some answers. The source of this outbreak was a white-tailed deer that had been butchered and eaten at the school. The risk factors for infection were handling raw or eating undercooked venison. To prevent this type of STECinfection, people should handle and cook venison with the same caution recommended for other meats
Sustaining The Saco Estuary: Final Report 2015
This study focuses on the Saco estuary, the tidal portion of the Saco River, which drains the largest watershed in southern Maine. With headwaters in the White Mountains of New Hampshire, the watershed encompasses more than 4,400 km2, and provides clean healthy drinking water to over 100,000 people living and working in communities in southern Maine.
When the study began in 2009, very little was known about the ecology of the Saco estuary. Researchers at the University of New England and the Wells National Estuarine Research Reserve employed the process of collaborative learning to bring together people who care about the estuary in order to identify their concerns. A Stewardship Network composed of people employed by municipal, state and federal governments, water supply organizations and businesses, volunteers from municipal boards making land use decisions, land trusts, property owners and representatives from other organizations that are uniquely focused on the region was formed. The Stewardship Network helped to define the project goals and objectives, and provided input and guidance over the five-year project.
This report explains what the researchers discovered about the ecology of the estuary, along with what they learned about its social and economic components. This baseline assessment contributes to the long-term goal of restoring and sustaining the structure and function of the estuary, and supports the efforts of government, businesses and local organizations that value the estuary and depend upon the natural services it provides
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