Functional Interactions of Alcohol-sensitive Sites in the \u3cem\u3eN\u3c/em\u3e-Methyl-d-aspartate Receptor M3 and M4 Domains

The N-methyl-d-aspartate receptor is an important mediator of the behavioral effects of ethanol in the central nervous system. Previous studies have demonstrated sites in the third and fourth membrane-associated (M) domains of the N-methyl-d-aspartate receptor NR2A subunit that influence alcohol sensitivity and ion channel gating. We investigated whether two of these sites, Phe-637 in M3 and Met-823 in M4, interactively regulate the ethanol sensitivity of the receptor by testing dual substitution mutants at these positions. A majority of the mutations decreased steady-state glutamate EC50 values and maximal steady-state to peak current ratios (Iss/Ip), whereas only two mutations altered peak glutamate EC50 values. Steady-state glutamate EC50 values were correlated with maximal glutamate Iss/Ip values, suggesting that changes in glutamate potency were attributable to changes in desensitization. In addition, there was a significant interaction between the substituents at positions 637 and 823 with respect to glutamate potency and desensitization. IC50 values for ethanol among the mutants varied over the approximate range 100–325 mm. The sites in M3 and M4 significantly interacted in regulating ethanol sensitivity, although this was apparently dependent upon the presence of methionine in position 823. Molecular dynamics simulations of the NR2A subunit revealed possible binding sites for ethanol near both positions in the M domains. Consistent with this finding, the sum of the molecular volumes of the substituents at the two positions was not correlated with ethanol IC50 values. Thus, there is a functional interaction between Phe-637 and Met-823 with respect to glutamate potency, desensitization, and ethanol sensitivity, but the two positions do not appear to form a unitary site of alcohol action

Diffusion dominated process for the crystal growth of a binary alloy

The pure diffusion process has been often used to study the crystal growth of a binary alloy in the microgravity environment. In the present paper, a geometric parameter, the ratio of the maximum deviation distance of curved solidification and melting interfaces from the plane to the radius of the crystal rod, was adopted as a small parameter, and the analytical solution was obtained based on the perturbation theory. The radial segregation of a diffusion dominated process was obtained for cases of arbitrary Peclet number in a region of finite extension with both a curved solidification interface and a curved melting interface. Two types of boundary conditions at the melting interface were analyzed. Some special cases such as infinite extension in the longitudinal direction and special range of Peclet number were reduced from the general solution and discussed in detail

Native Texas Ornamental Bunchgrass Performance Under Water Restrictions

Growing human populations and increasing drought conditions compete with ornamental grassland landscapes for freshwater resources. With outdoor use as the largest consumer of municipal water, irrigation restrictions will likely be increasingly implemented, restricting ornamental municipal grasslands. Substituting irrigation-dependent exotic grasses with drought-adapted native bunchgrasses could help mitigate this problem. Greenhouse (GH) trials revealed exotic ornamental bunchgrasses declined faster than natives under progressive water stress, with natives performing best under moderate water with maximum water treatments decreasing aesthetic quality. There was wide variability among accessions, indicating promising genetic diversity from which to select drought resistance for ornamentals. Native grasses performed best in field trials with supplemental irrigation during warm-season growth and restricted irrigation during the cool season. In northcentral Texas, native little bluestem (LBS; Schizachyrium scoparium L.) accessions outperformed exotics in health and aesthetics across environments. Most response variables were species as well as accession dependent. Select LBS accessions are recommended for commercialization for municipal grasslands due to superior field performance under water restrictions. Replacing favored water-intensive exotic grasses with adapted native grasses could help reduce irrigation water use

Semliki Forest virus induced, immune mediated demyelination: the effect of irradiation

International audienceThe Dark Energy Camera has captured a large set of images as part of Science Verification (SV) for the Dark Energy Survey (DES). The SV footprint covers a large portion of the outer Large Magellanic Cloud (LMC), providing photometry 1.5 mag fainter than the main sequence turn-off of the oldest LMC stellar population. We derive geometrical and structural parameters for various stellar populations in the LMC disc. For the distribution of all LMC stars, we find an inclination of i = -38.14° ± 0.08° (near side in the north) and a position angle for the line of nodes of θ0 = 129.51° ± 0.17°. We find that stars younger than ∼4 Gyr are more centrally concentrated than older stars. Fitting a projected exponential disc shows that the scale radius of the old populations is R>4 Gyr = 1.41 ± 0.01 kpc, while the younger population has R = 0.72 ± 0.01 kpc. However, the spatial distribution of the younger population deviates significantly from the projected exponential disc model. The distribution of old stars suggests a large truncation radius of Rt = 13.5 ± 0.8 kpc. If this truncation is dominated by the tidal field of the Galaxy, we find that the LMC is {∼eq } 24^{+9}_{-6} times less massive than the encircled Galactic mass. By measuring the Red Clump peak magnitude and comparing with the best-fitting LMC disc model, we find that the LMC disc is warped and thicker in the outer regions north of the LMC centre. Our findings may either be interpreted as a warped and flared disc in the LMC outskirts, or as evidence of a spheroidal halo component

Health and Occupational Injury Experienced by Latinx Child Farmworkers in North Carolina, USA

Children as young as 10 years old are hired to work on farms in the United States (U.S.). These children are largely Latinx. Using interview data collected from 202 North Carolina Latinx child farmworkers in 2017, this analysis documents the heath characteristics and occupational injuries of Latinx child farmworkers and delineates characteristics associated with their health and occupational injuries. Latinx child farmworkers include girls (37.6%) and boys (62.4%), aged 10 to 17 years, with 17.8% being migrant farmworkers. Three-quarters reported receiving medical and dental care in the past year. Respiratory (15.8%) and vision (20.3%) problems were prevalent. Girls more than boys, and younger more than older children had greater health service utilization. Occupational injuries were common, with 26.2% reporting a traumatic injury, 44.1% a dermatological injury, 42.6% a musculoskeletal injury, and 45.5% heat-related illness in the past year. Age increased the odds of reporting work injuries and heat-related illness, and being a non-migrant reduced the odds of reporting work injuries. These results emphasize the need for greater documentation of child farmworker occupational health and safety. They underscore the need to change occupational safety policy to ensure that children working in agriculture have the same protections as those working in all other U.S. industries

Supernova / Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

The Supernova / Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universe's expansion by performing a series of complementary systematics-controlled measurements. We describe a self-consistent reference mission design for building a Type Ia supernova Hubble diagram and for performing a wide-area weak gravitational lensing study. A 2-m wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high-efficiency low-resolution integral field spectrograph. The SNAP mission will obtain high-signal-to-noise calibrated light-curves and spectra for several thousand supernovae at redshifts between z=0.1 and 1.7. A wide-field survey covering one thousand square degrees resolves ~100 galaxies per square arcminute. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and flatness of space can all be measured with SNAP supernova and weak-lensing measurements to a systematics-limited accuracy of 1%. For a flat universe, the density-to-pressure ratio of dark energy can be similarly measured to 5% for the present value w0 and ~0.1 for the time variation w'. The large survey area, depth, spatial resolution, time-sampling, and nine-band optical to NIR photometry will support additional independent and/or complementary dark-energy measurement approaches as well as a broad range of auxiliary science programs. (Abridged)Comment: 40 pages, 18 figures, submitted to PASP, http://snap.lbl.go

The Angular Correlation Function of Galaxies from Early SDSS Data

The Sloan Digital Sky Survey is one of the first multicolor photometric and spectroscopic surveys designed to measure the statistical properties of galaxies within the local Universe. In this Letter we present some of the initial results on the angular 2-point correlation function measured from the early SDSS galaxy data. The form of the correlation function, over the magnitude interval 18<r*<22, is shown to be consistent with results from existing wide-field, photographic-based surveys and narrower CCD galaxy surveys. On scales between 1 arcminute and 1 degree the correlation function is well described by a power-law with an exponent of ~ -0.7. The amplitude of the correlation function, within this angular interval, decreases with fainter magnitudes in good agreement with analyses from existing galaxy surveys. There is a characteristic break in the correlation function on scales of approximately 1-2 degrees. On small scales, < 1', the SDSS correlation function does not appear to be consistent with the power-law form fitted to the 1'< theta <0.5 deg data. With a data set that is less than 2% of the full SDSS survey area, we have obtained high precision measurements of the power-law angular correlation function on angular scales 1' < theta < 1 deg, which are robust to systematic uncertainties. Because of the limited area and the highly correlated nature of the error covariance matrix, these initial results do not yet provide a definitive characterization of departures from the power-law form at smaller and larger angles. In the near future, however, the area of the SDSS imaging survey will be sufficient to allow detailed analysis of the small and large scale regimes, measurements of higher-order correlations, and studies of angular clustering as a function of redshift and galaxy type