2,539 research outputs found
A range expanding signal conditioner
Telemetry system modifications to improve signal resolution are described. Process uses zero suppression technique which consists of subtracting known voltage from input and amplifying remainder. Schematic diagram of circuit is provided and details of operation are presented
Natural Killer Cell Function and Dysfunction in Hepatitis C Virus Infection
Viruses must continually adapt against dynamic innate and adaptive responses of the host immune system to establish chronic infection. Only a small minority (ā¼20%) of those exposed to hepatitis C virus (HCV) spontaneously clear infection, leaving approximately 200 million people worldwide chronically infected with HCV. A number of recent research studies suggest that establishment andmaintenance of chronicHCVinfection involve natural killer (NK) cell dysfunction. This relationship is illustrated in vitro by disruption of typicalNK cell responses including both cell-mediated cytotoxicity and cytokine production. Expression of a number of activating NK cell receptors in vivo is also affected in chronic HCV infection.Thus, direct in vivo and in vitro evidence
of compromised NK function in chronic HCV infection in conjunction with significant epidemiological associations between the outcome of HCV infection and certain combinations of NK cell regulatory receptor and class I human histocompatibility linked antigen (HLA) genotypes indicate that NK cells are important in the immune response against HCV infection. In this review, we
highlight evidence suggesting that selective impairment of NK cell activity is related to establishment of chronic HCV infection
Leveraging Geospatial Information to address Space Epidemiology through Multi\unicode{x2013}omics \unicode{x2013} Report of an Interdisciplinary Workshop
This article will summarize the workshop proceedings of a workshop conducted
at the University of Missouri that addressed the use of multi-omics fused with
geospatial information to assess and improve the precision and environmental
analysis of indicators of crew space health. The workshop addressed the state
of the art of multi-omics research and practice and the potential future use of
multi-omics platforms in extreme environments. The workshop also focused on
potential new strategies for data collection, analysis, and fusion with
crosstalk with the field of environmental health, biosecurity, and radiation
safety, addressing gaps and shortfalls and potential new approaches to
enhancing astronaut health safety and security. Ultimately, the panel
proceedings resulted in a synthesis of new research and translational
opportunities to improve space and terrestrial epidemiology. In the future,
early disease prevention that employs new and expanded data sources enhanced by
the analytic precision of geospatial information and artificial intelligence
algorithms.Comment: 9 pages, 1 figur
Groundwater trend analysis and salinity risk assessment for the south-west agricultural region of Western Australia, 2007ā12
Dryland salinity is a hydrologically driven land degradation hazard in the south-west agricultural region of Western Australia (WA). Shallow-rooted annual crops and pastures transpire significantly less water than the native vegetation they replaced, leading to an increase in recharge, rising groundwater levels and the development of shallow watertables in areas where often none existed previously. Rising groundwater levels mobilise soluble salts, naturally stored at high concentrations in the regolith. These salts can be concentrated in the root zone of vegetation by evapotranspiration
High levels of childhood obesity observed among 3- to 7-year-old New Zealand Pacific children is a public health concern.
This cross-sectional, community-based survey was designed to assess attained growth and body composition of 3- to 7-y-old Pacific children (n = 21 boys and 20 girls) living in Dunedin, New Zealand, and to examine nondietary factors associated with the percentage of body fat. Fat mass, lean tissue mass and the percentage of body fat were measured using dual energy X-ray absorptiometry. One trained anthropometrist also measured height, weight, skinfolds (triceps, subscapular) and circumferences (mid-upper arm, chest, waist, calf). Compared with the National Center for Health Statistics and National Health and Examination Surveys I and II reference data, these Pacific children were tall and heavy for their age with high arm-muscle-area-for-height. Median (quartiles) Z-scores for height and BMI-for-age and arm-muscle-area-for-height were 1.33 (0.60, 2.15), 1.20 (0.74, 4.43) and 1.09 (0.63, 1.85), respectively. Their median (quartile) percentage of body fat was 21.8% (15.0, 35.5) of which 38.5% was located in the trunk. The estimated percentage of children classified as obese ranged from 34 to 49% depending on the criterion used. Over 60% of the children had levels of trunk fat above 1 SD of reported age- and sex-specific Z-scores for New Zealand children. The nondietary factors examined (hours of television viewing and hours playing organized sports, as reported by parents) were not associated with variations in the percentage of body fat, after adjusting for age, sex and birth weight. These extremely high levels of obesity and truncal fat among very young New Zealand children will have major public health implications as these children age
Ozone depletion events observed in the high latitude surface layer during the TOPSE aircraft program
During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58Ā° between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as Baffin Bay and Hudson Bay and as late as 22 May. There is good evidence that these more southern events did not form in situ but were the result of export of ozone-depleted air from the surface layer of the Arctic Ocean. Surprisingly, relatively intact transport of ODEs occurred over distances of 900ā2000 km and in some cases over rough terrain. Accumulation of constituents in the frozen surface over the dark winter period cannot be a strong prerequisite of ozone depletion since latitudes south of the Arctic Ocean would also experience a long dark period. Some process unique to the Arctic Ocean surface or its coastal regions remains unidentified for the release of ozone-depleting halogens. There was no correspondence between coarse surface features such as solid ice/snow, open leads, or polynyas with the occurrence of or intensity of ozone depletion over the Arctic or subarctic regions. Depletion events also occurred in the absence of long-range transport of relatively fresh āpollutionā within the high latitude surface layer, at least in spring 2000. Direct measurements of halogen radicals were not made. However, the flights do provide detailed information on the vertical structure of the surface layer and, during the constant 30 m altitude legs, measurements of a variety of constituents including hydroxyl and peroxy radicals. A summary of the behavior of these constituents is made. The measurements were consistent with a source of formaldehyde from the snow/ice surface. Median NOx in the surface layer was 15 pptv or less, suggesting that surface emissions were substantially converted to reservoir constituents by 30 m altitude and that ozone production rates were small (0.15ā1.5 ppbv/d) at this altitude. Peroxyacetylnitrate (PAN) was by far the major constituent of NOy in the surface layer independent of the ozone mixing ratio
Data-driven discovery of the spatial scales of habitat choice by elephants
Setting conservation goals and management objectives relies on understanding
animal habitat preferences. Models that predict preferences combine location data
fromtracked animals with environmental information, usually at a spatial resolution
determined by the available data. This resolution may be biologically irrelevant for
the species in question. Individuals likely integrate environmental characteristics
over varying distances when evaluating their surroundings; we call this the scale of
selection. Even a single characteristic might be viewed differently at different scales;
for example, a preference for sheltering under trees does not necessarily imply a
fondness for continuous forest. Multi-scale preference is likely to be particularly
evident for animals that occupy coarsely heterogeneous landscapes like savannahs.
We designed a method to identify scales at which species respond to resources and
used these scales to build preference models. We represented different scales of
selection by locally averaging, or smoothing, the environmental data using kernels
of increasing radii. First, we examined each environmental variable separately across
a spectrum of selection scales and found peaks of fit. These ācandidateā scales then
determined the environmental data layers entering a multivariable conditional
logistic model. We used model selection via AIC to determine the important
predictors out of this set. We demonstrate this method using savannah elephants (Loxodonta africana) inhabiting two parks in southern Africa. The multi-scale
models were more parsimonious than models using environmental data at only
the source resolution. Maps describing habitat preferences also improved when
multiple scales were included, as elephants were more often in places predicted to
have high neighborhood quality.We conclude that elephants select habitat based on
environmental qualities at multiple scales. For them, and likely many other species,
biologists should include multiple scales in models of habitat selection. Species
environmental preferences and their geospatial projections will be more accurately
represented, improving management decisions and conservation planning.The fieldwork was funded through grants fromthe US Fish andWildlife Service (98210-2-
G365, 98210-3-G651 & 98210-2-G300) and the Peace Parks Foundation (PPF/P/24) to RJ
van Aarde.https://peerj.comam201
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