745 research outputs found
Modeling Multi-Wavelength Stellar Astrometry. II. Determining Absolute Inclinations, Gravity Darkening Coefficients, and Spot Parameters of Single Stars with SIM Lite
We present a novel technique to determine the absolute inclination of single
stars using multi-wavelength sub-milliarcsecond astrometry. The technique
exploits the effect of gravity darkening, which causes a wavelength-dependent
astrometric displacement parallel to a star's projected rotation axis. We find
this effect is clearly detectable using SIM Lite for various giant stars and
rapid rotators, and present detailed models for multiple systems using the
REFLUX code. We also explore the multi-wavelength astrometric reflex motion
induced by spots on single stars. We find that it should be possible to
determine spot size, relative temperature, and some positional information for
both giant and nearby main-sequence stars utilizing multi-wavelength SIM Lite
data. This data will be extremely useful in stellar and exoplanet astrophysics,
as well as supporting the primary SIM Lite mission through proper
multi-wavelength calibration of the giant star astrometric reference frame, and
reduction of noise introduced by starspots when searching for extrasolar
planets.Comment: 8 pages, 7 figures, 4 tables. Accepted for publication in the
Astrophysical Journa
Effect of short-term lycopene supplementation and postprandial dyslipidemia on plasma antioxidants and biomarkers of endothelial health in young, healthy individuals
The objective of this study was to test the hypothesis that the effect of a high-fat meal (HFm) on plasma lipid-soluble antioxidants and biomarkers of vascular oxidative stress and inflammation would be attenuated by short-term lycopene supplementation in young healthy subjects. Following restriction of lycopene-containing foods for 1-wk (LYr), blood was collected in a fasting state and 3 h after a HFm and a low-fat meal (LFm) in N = 18 men aged 23 ± 2 years, and after a HFm only in N = 9 women aged 23 ± 1 years. Blood was also sampled pre- and post-meals following 1-wk of 80 mg/day lycopene supplementation (LYs) under continued dietary LYr. In the fasting state, LYs compared with LYr not only evoked a >2-fold increase in plasma lycopene but also increased plasma ÎČ-carotene and α-tocopherol (p < 0.01), though LYs did not affect plasma nitrate/nitrite (biomarker of nitric oxide), malondialdehyde (biomarker of lipid oxidative stress), vascular- and intercellular-adhesion molecules or C-reactive protein (biomarkers of inflammation). Contrary to the hypothesis, the HFm-induced dyslipidemic state did not affect plasma malondialdehyde, C-reactive protein, or adhesion molecules in either LYr or LYs. Both the HFm and LFm were associated with decreases in the nitric oxide metabolites nitrate/nitrite and lipid-soluble antioxidants (p < 0.05). The data revealed that 1-wk of LYs increased plasma lycopene, ÎČ-carotene, and α-tocopherol yet despite these marked changes to the plasma lipid-soluble antioxidant pool, biomarkers of vascular oxidative stress and inflammation were unaffected in the fasted state as well as during dyslipidemia induced by a HFm in young healthy subjects
A survey of phytoestrogenic activity in Kansas flint hills pastures
The botanical composition and basal
cover of three Kansas Flint Hills pastures
located in Butler and Chase counties was
surveyed to estimate the incidence of plant
species that contain appreciable levels of
estrogenic activity. Many-flowered scurfpea
and Ladino clover were the only plant species
classified as high in estrogenic activity.
Although significant estrogenic activity
existed in specific species, the willingness of
livestock to consume those species is unclear
Prevalence of intestinal microsporidiosis in Human Immunodeficiency Virus-infected patients with diarrhea in major United States cities
To determine the prevalence of intestinal microsporidiosis in HIV-infected patients, we performed a prospective study of HIV-infected patients with diarrheal illnesses in three US hospitals and examined an observational database of HIV-infected patients in 10 US cities. Among 737 specimens from the three hospitals, results were positive for 11 (prevalence 1.5%); seven (64%) acquired HIV through male-to-male sexual contact, two (18%) through male-to-male sexual contact and injection drug use, and one (9%) through heterosexual contact; one (9%) had an undetermined mode of transmission. Median CD4 count within six months of diagnosis of microsporidiosis was 33 cells/”L (range 3 to 319 cells/”L). For the national observational database (n = 24,098), the overall prevalence of microsporidiosis was 0.16%. Prevalence of microsporidiosis among HIV-infected patients with diarrheal disease is low, and microsporidiosis is most often diagnosed in patients with very low CD4+ cell counts. Testing for microsporidia appears to be indicated, especially for patients with very low CD4+ cell counts.Para determinar a prevalĂȘncia de microsporidiose intestinal em pacientes infectados pelo HIV foi realizado um estudo prospectivo em trĂȘs hospitais dos Estados Unidos da AmĂ©rica do Norte (EUA) e analizada uma base de dados nacional composta de dados coletados de pacientes infectados pelo HIV em 10 cidades dos EUA. De um total de 737 amostras de fezes de pacientes infectados pelo HIV que apresentavam diarrĂ©ia, amostras de 11 pacientes (prevalĂȘncia de 1,5%) foram positivas para microsporĂdios. Todos os positivos eram do sexo masculino e, entre eles, sete (64%) pacientes adquiriram a infecção pelo HIV atravĂ©s de relação homossexual, dois (18%) atravĂ©s de relação sexual e drogas injetĂĄveis e um (9%) atravĂ©s de contato heterosexual, enquanto que em um paciente o modo de transmissĂŁo do HIV nĂŁo foi determinado. A contagem mĂ©dia de linfĂłcitos CD4 realizada atĂ© seis meses do diagnĂłstico de microsporidiose foi de 33 cĂ©lulas/microlitro (3 a 319 cĂ©lulas/microlitro). A anĂĄlise da base de dados nacional (n = 24.098) mostrou uma prevalĂȘncia de microsporidiose de 0,16%. A prevalĂȘncia de microsporidiose em pacientes HIV-positivos com diarrĂ©ia Ă© baixa. Entretando, como a microsporidiose Ă© mais frequentemente diagnosticada em pacientes com contagens de CD4 muito baixas, a indicação de pesquisa de microsporĂdios Ă© justificada, especialmente para estes pacientes
Risk of nonalcoholic fatty liver disease and associations with gastrointestinal cancers
Metabolic syndrome may contribute to the rising incidence of multiple gastrointestinal (GI) cancers in recent birth cohorts. However, other than hepatocellular carcinoma, the association between nonalcoholic fatty liver disease (NAFLD) and risk of non-liver GI cancers is unexplored. We prospectively examined the associations of NAFLD risk with GI cancers among 319,290 participants in the UK Biobank (2006-2019). Baseline risk for NAFLD was estimated using the Dallas Steatosis Index, a validated prediction tool. Multivariable Cox models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) according to NAFLD risk categories: low (\u3c20%), intermediate (20%-49%), and high (â„50%). We also examined the associations by age of cancer diagnosis (earlier onset [\u3c60] vs. â„60). A total of 273 incident liver cancer and 4789 non-liver GI cancer cases were diagnosed. Compared with individuals at low risk for NAFLD, those at high risk had 2.41-fold risk of liver cancer (RR = 2.41, 95% CI: 1.73-3.35) and 23% increased risk of non-liver GI cancers (RR = 1.23, 95% CI: 1.14-1.32) (all
Detection of Viruses from Bioaerosols Using Anion Exchange Resin
This protocol demonstrates a customized bioaerosol sampling method for viruses. In this system, anion exchange resin is coupled with liquid impingement-based air sampling devices for efficacious concentration of negatively-charged viruses from bioaerosols. Thus, the resin serves as an additional concentration step in the bioaerosol sampling workflow. Nucleic acid extraction of the viral particles is then performed directly from the anion exchange resin, with the resulting sample suitable for molecular analyses. Further, this protocol describes a custom-built bioaerosol chamber capable of generating virus-laden bioaerosols under a variety of environmental conditions and allowing for continuous monitoring of environmental variables such as temperature, humidity, wind speed, and aerosol mass concentration. The main advantage of using this protocol is increased sensitivity of viral detection, as assessed via direct comparison to an unmodified conventional liquid impinger. Other advantages include the potential to concentrate diverse negatively-charged viruses, the low cost of anion exchange resin (~$0.14 per sample), and ease of use. Disadvantages include the inability of this protocol to assess infectivity of resin-adsorbed viral particles, and potentially the need for the optimization of the liquid sampling buffer used within the impinger
Inter-cage dynamics in structure I, II, and H fluoromethane hydrates as studied by NMR and molecular dynamics simulations
Short intense ion pulses for materials and warm dense matter research
We have commenced experiments with intense short pulses of ion beams on the
Neutralized Drift Compression Experiment-II at Lawrence Berkeley National
Laboratory, by generating beam spots size with radius r < 1 mm within 2 ns FWHM
and approximately 10^10 ions/pulse. To enable the short pulse durations and
mm-scale focal spot radii, the 1.2 MeV Li+ ion beam is neutralized in a
1.6-meter drift compression section located after the last accelerator magnet.
An 8-Tesla short focal length solenoid compresses the beam in the presence of
the large volume plasma near the end of this section before the target. The
scientific topics to be explored are warm dense matter, the dynamics of
radiation damage in materials, and intense beam and beam-plasma physics
including selected topics of relevance to the development of heavy-ion drivers
for inertial fusion energy. Here we describe the accelerator commissioning and
time-resolved ionoluminescence measurements of yttrium aluminium perovskite
using the fully integrated accelerator and neutralized drift compression
components.Comment: 7 pages, 9 figure
Optimizing land use decision-making to sustain Brazilian agricultural profits, biodiversity and ecosystem services
AbstractDesigning landscapes that can meet human needs, while maintaining functioning ecosystems, is essential for long-term sustainability. To achieve this goal, we must better understand the trade-offs and thresholds in the provision of ecosystem services and economic returns. To this end, we integrate spatially explicit economic and biophysical models to jointly optimize agricultural profit (sugarcane production and cattle ranching), biodiversity (bird and mammal species), and freshwater quality (nitrogen, phosphorus, and sediment retention) in the Brazilian Cerrado. We generate efficiency frontiers to evaluate the economic and environmental trade-offs and map efficient combinations of agricultural land and natural habitat under varying service importance. To assess the potential impact of the Brazilian Forest Code (FC), a federal policy that aims to promote biodiversity and ecosystem services on private lands, we compare the frontiers with optimizations that mimic the habitat requirements in the region. We find significant opportunities to improve both economic and environmental outcomes relative to the current landscape. Substantial trade-offs between biodiversity and water quality exist when land use planning targets a single service, but these trade-offs can be minimized through multi-objective planning. We also detect non-linear profit-ecosystem services relationships that result in land use thresholds that coincide with the FC requirements. Further, we demonstrate that landscape-level planning can greatly improve the performance of the FC relative to traditional farm-level planning. These findings suggest that through joint planning for economic and environmental goals at a landscape-scale, Brazil's agricultural sector can expand production and meet regulatory requirements, while maintaining biodiversity and ecosystem service provision
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