184 research outputs found
Detection of Viral Hemorrhagic Septicemia Virus (VHSV) from Diporeia spp. (Pontoporeiidae, Amphipoda) in the Laurentian Great Lakes, USA
The mode of viral hemorrhagic septicemia virus (VHSV) transmission in the Great Lakes basin is largely unknown. In order to assess the potential role of macroinvertebrates in VHSV transmission, Diporeia spp., a group of amphipods that are preyed upon by a number of susceptible Great Lakes fishes, were collected from seven locations in four of the Great Lakes and analyzed for the presence of VHSV. It was demonstrated that VHSV is present in some Diporeia spp. samples collected from lakes Ontario, Huron, and Michigan, but not from Lake Superior. Phylogenetic comparison of partial nucleoprotein (N) gene sequences (737 base pairs) of the five isolates to sequences of 13 other VHSV strains showed the clustering of Diporeia spp. isolates with the VHSV genotype IVb. This study reports the first incidence of a fish-pathogenic rhabdovirus being isolated from Diporeia, or any other crustacean and underscores the role macroinvertebrates may play in VHSV ecology
Exploring Household Food Insecurity and Inter-generational Self-help Club Involvement Among Grandparents Raising Grandchildren Due to HIV/AIDS in Vietnam
Intergenerational Self-help Clubs (ISHCs), also known as âEmpathy Clubsâ in Vietnam may aid in improving quality of life and well-being for grandparent-headed households impacted by HIV/AIDS. However, less is known about how club membership impacts household food security. This cross-sectional, mixed methods study examines the differences in household food security and coping responses to food insecurity among 30 grandparents who are raising grandchildren due to HIV/AIDS, 15 who were involved in ISHC groups and 15 who were not involved in ISHC groups, in Hai Phong, Vietnam. In addition to qualitative interviews, all grandparents completed the Household Food Security Insecurity Access Scale (HFIAS) to assess the prevalence of food insecurity. Chi-square and t-tests were employed to detect differences between ISHC members and nonmembers. The food security domain of anxiety and uncertainty related to having enough food was statistically significant (t [28] = 2.27, p \u3c 0.03), with ISHC participants reporting less anxiety and uncertainty. Close to half (46%) of ISHC members reported mild food insecurity. By comparison, about the same percentage (47%) of nonmembers reported moderate food insecurity. Qualitative interviews revealed that food insecurity arose from barriers to accessing food, which led to three primary coping responses: 1) reconfiguring understandings of age-related nutritional needs, 2) erosive coping, and 3) engaging networks for nutritional support. Differences between members of the ISHCs and those without club involvement suggest that a strong community connection, perhaps bonding social capital, may play a role in reducing anxiety related to having enough food. Findings suggest that ISHCs may build social capital, provide psychosocial support, and increase food security among grandparent-headed households who face vulnerability
Avalanches on a conical bead pile: scaling with tuning parameters
Uniform spherical beads were used to explore the behavior of a granular
system near its critical angle of repose on a conical bead pile. We found two
tuning parameters that could take the system to a critical point where a simple
power-law described the avalanche size distribution as predicted by
self-organized criticality, which proposed that complex dynamical systems
self-organize to a critical point without need for tuning. Our distributions
were well described by a simple power-law with the power {\tau} = 1.5 when
dropping beads slowly onto the apex of a bead pile from a small height.
However, we could also move the system from the critical point using either of
two tuning parameters: the height from which the beads fell onto the top of the
pile or the region over which the beads struck the pile. As the drop height
increased, the system did not reach the critical point yet the resulting
distributions were independent of the bead mass, coefficient of friction, or
coefficient of restitution. All our apex-dropping distributions for any type of
bead (glass, stainless steel, zirconium) showed universality by scaling onto a
common curve with {\tau} = 1.5 and {\sigma} = 1.0, where 1/{\sigma} is the
power of the tuning parameter. From independent calculations using the moments
of the distribution, we find values for {\tau} = 1.6 \pm 0.1 and {\sigma} =
0.91 \pm 0.15. When beads were dropped across the surface of the pile instead
of solely on the apex, then the system also moved from the critical point and
again the avalanche size distributions fell on a common curve when scaled
similarly using the same values of {\tau} and {\sigma}. We also observed that
an hcp structure on the base of the pile caused an emergent structure in the
pile that had six faces with some fcc or hcp structure.Comment: 8 pages, 6 figures; submitted to Granular Matter; Reformatted into
LaTeX from Word; Fixed typo in uncertainty of tau; Rearranged two paragraphs
to improve flo
Bacteria in the amniotic fluid without inflammation: Early colonization vs. contamination
Objectives: Intra-amniotic infection, defined by the presence of microorganisms in the amniotic cavity, is often accompanied by intra-amniotic inflammation. Occasionally, laboratories report the growth of bacteria or the presence of microbial nucleic acids in amniotic fluid in the absence of intra-amniotic inflammation. This study was conducted to determine the clinical significance of the presence of bacteria in amniotic fluid samples in the absence of intra-amniotic inflammation. Methods: A retrospective cross-sectional study included 360 patients with preterm labor and intact membranes who underwent transabdominal amniocentesis for evaluation of the microbial state of the amniotic cavity as well as intra-amniotic inflammation. Cultivation techniques were used to isolate microorganisms, and broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was utilized to detect the nucleic acids of bacteria, viruses, and fungi. Results: Patients whose amniotic fluid samples evinced microorganisms but did not indicate inflammation had a similar perinatal outcome to those without microorganisms or inflammation [amniocentesis-to-delivery interval (p=0.31), spontaneous preterm birth before 34 weeks (p=0.83), acute placental inflammatory lesions (p=1), and composite neonatal morbidity (p=0.8)]. Conclusions: The isolation of microorganisms from a sample of amniotic fluid in the absence of intra-amniotic inflammation is indicative of a benign condition, which most likely represents contamination of the specimen during the collection procedure or laboratory processing rather than early colonization or infection
TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844
Data from the newly-commissioned \textit{Transiting Exoplanet Survey
Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf
located 15 pc away. The planet has a radius of and
orbits the star every 11 hours. Although the existence of an atmosphere around
such a strongly irradiated planet is questionable, the star is bright enough
(, ) for this possibility to be investigated with transit and
occultation spectroscopy. The star's brightness and the planet's short period
will also facilitate the measurement of the planet's mass through Doppler
spectroscopy.Comment: 10 pages, 4 figures. Submitted to ApJ Letters. This letter makes use
of the TESS Alert data, which is currently in a beta test phase, using data
from the pipelines at the TESS Science Office and at the TESS Science
Processing Operations Cente
275 Candidates and 149 Validated Planets Orbiting Bright Stars in K2 Campaigns 0-10
Since 2014, NASA's K2 mission has observed large portions of the ecliptic
plane in search of transiting planets and has detected hundreds of planet
candidates. With observations planned until at least early 2018, K2 will
continue to identify more planet candidates. We present here 275 planet
candidates observed during Campaigns 0-10 of the K2 mission that are orbiting
stars brighter than 13 mag (in Kepler band) and for which we have obtained
high-resolution spectra (R = 44,000). These candidates are analyzed using the
VESPA package (Morton 2012, 2015b) in order to calculate their false-positive
probabilities (FPP). We find that 149 candidates are validated with an FPP
lower than 0.1%, 39 of which were previously only candidates and 56 of which
were previously undetected. The processes of data reduction, candidate
identification, and statistical validation are described, and the demographics
of the candidates and newly validated planets are explored. We show tentative
evidence of a gap in the planet radius distribution of our candidate sample.
Comparing our sample to the Kepler candidate sample investigated by Fulton et
al. (2017), we conclude that more planets are required to quantitatively
confirm the gap with K2 candidates or validated planets. This work, in addition
to increasing the population of validated K2 planets by nearly 50% and
providing new targets for follow-up observations, will also serve as a
framework for validating candidates from upcoming K2 campaigns and the
Transiting Exoplanet Survey Satellite, expected to launch in 2018.Comment: Published in AJ, 47 pages, 18 figures, 7 tables, associated
supplementary dataset available at https://zenodo.org/record/116479
TOI 540 b: A Planet Smaller than Earth Orbiting a Nearby Rapidly Rotating Low-mass Star
We present the discovery of TOI 540 b, a hot planet slightly smaller than
Earth orbiting the low-mass star 2MASS J05051443-4756154. The planet has an
orbital period of days ( 170 ms) and a radius of , and is likely terrestrial based on the observed
mass-radius distribution of small exoplanets at similar insolations. The star
is 14.008 pc away and we estimate its mass and radius to be and , respectively. The
star is distinctive in its very short rotational period of hours and correspondingly small Rossby number of 0.007 as
well as its high X-ray-to-bolometric luminosity ratio of based on a serendipitous XMM-Newton detection during a slew operation.
This is consistent with the X-ray emission being observed at a maximum value of
as predicted for the most rapidly rotating M
dwarfs. TOI 540 b may be an alluring target to study atmospheric erosion due to
the strong stellar X-ray emission. It is also among the most accessible targets
for transmission and emission spectroscopy and eclipse photometry with JWST,
and may permit Doppler tomography with high-resolution spectroscopy during
transit. This discovery is based on precise photometric data from TESS and
ground-based follow-up observations by the MEarth team.Comment: 18 pages, 7 figures. Accepted for publication in The Astronomical
Journa
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
- âŠ