Ecological Risk Assessment for Highways in the Chesapeake Bay Watershed

The population of coastal counties in the United States is over six-fold higher than non-coastal counties and population density along the Atlantic coast is much greater than all other coasts in the nation. Many areas around the Chesapeake Bay watershed are participating in this growth and extensive interstate construction is planned for this region. A wide array of primary ecological risks to the Chesapeake Bay exists, and may be classified as biological, physical, or chemical. Biological risks range from physical threats to motorists and animals to genetic risks to local flora and fauna populations. Island biogeography theory can be used to predict species losses associated with highway construction and resultant limits to migration. Introduction of exotic species and loss of ecologically significant areas (e.g. wetlands) are included as biological risks. Physical risks are primarily associated with hydrology, erosion, and related water quality considerations. Chemical concerns can be described as either chronic, such as certain airborne pollutants, or acute, such as accidental or illegal discharges. Secondary risks associated with highway construction result from facilitated traffic flow. Included are a variety of effects resulting from urban sprawl, strip development, and economic development of adjacent areas. Some ecological risks have received legislative, and subsequently transportation department attention. However, most ecological risks do not affect the decision-making process.https://scholarworks.wm.edu/vimsbooks/1179/thumbnail.jp

4He experiments can serve as a database for determining the three-nucleon force

We report on microscopic calculations for the 4He compound system in the framework of the resonating group model employing realistic nucleon-nucleon and three nucleon forces. The resulting scattering phase shifts are compared to those of a comprehensive R-matrix analysis of all data in this system, which are available in numerical form. The agreement between calculation and analysis is in most cases very good. Adding three-nucleon forces yields in many cases large effects. For a few cases the new agreement is striking. We relate some differencies between calculation and analysis to specific data and discuss neccessary experiments to clarify the situation. From the results we conclude that the data of the 4He system might be well suited to determine the structure of the three-nucleon force.Comment: title changed,note added, format of figures changed, appearance of figures in black-and-white changed, Phys. Rev. C accepte

Plasma Transport in Saturn's Low‐Latitude Ionosphere: Cassini Data

An edited version of this paper was published by AGU. Copyright 2019 American Geophysical Union.In 2017 the Cassini Orbiter made the first in situ measurements of the upper atmosphere and ionosphere of Saturn. The Ion and Neutral Mass Spectrometer in its ion mode measured densities of light ion species (H+, H2+, H3+, and He+), and the Radio and Plasma Wave Science instrument measured electron densities. During proximal orbit 287 (denoted P287), Cassini reached down to an altitude of about 3,000 km above the 1 bar atmospheric pressure level. The topside ionosphere plasma densities measured for P287 were consistent with ionospheric measurements during other proximal orbits. Spacecraft potentials were measured by the Radio and Plasma Wave Science Langmuir probe and are typically about negative 0.3 V. Also, for this one orbit, Ion and Neutral Mass Spectrometer was operated in an instrument mode allowing the energies of incident H+ ions to be measured. H+ is the major ion species in the topside ionosphere. Ion flow speeds relative to Saturn's atmosphere were determined. In the southern hemisphere, including near closest approach, the measured ion speeds were close to zero relative to Saturn's corotating atmosphere, but for northern latitudes, southward ion flow of about 3 km/s was observed. One possible interpretation is that the ring shadowing of the southern hemisphere sets up an interhemispheric plasma pressure gradient driving this flow

Phonon Properties of Knbo3 and Ktao3 from First-Principles Calculations

The frequencies of transverse-optical $\Gamma$ phonons in KNbO$_3$ and KTaO$_3$ are calculated in the frozen-phonon scheme making use of the full-potential linearized muffin-tin orbital method. The calculated frequencies in the cubic phase of KNbO$_3$ and in the tetragonal ferroelectric phase are in good agreement with experimental data. For KTaO$_3$, the effect of lattice volume was found to be substantial on the frequency of the soft mode, but rather small on the relative displacement patterns of atoms in all three modes of the $T_{1u}$ symmetry. The TO frequencies in KTaO$_3$ are found to be of the order of, but somehow higher than, the corresponding frequencies in cubic KNbO$_3$.Comment: 8 pages + 1 LaTeX figure, Revtex 3.0, SISSA-CM-94-00

Imputation of variants from the 1000 Genomes Project modestly improves known associations and can identify low-frequency variant-phenotype associations undetected by HapMap based imputation

notes: PMCID: PMC3655956This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Genome-wide association (GWA) studies have been limited by the reliance on common variants present on microarrays or imputable from the HapMap Project data. More recently, the completion of the 1000 Genomes Project has provided variant and haplotype information for several million variants derived from sequencing over 1,000 individuals. To help understand the extent to which more variants (including low frequency (1% ≤ MAF <5%) and rare variants (<1%)) can enhance previously identified associations and identify novel loci, we selected 93 quantitative circulating factors where data was available from the InCHIANTI population study. These phenotypes included cytokines, binding proteins, hormones, vitamins and ions. We selected these phenotypes because many have known strong genetic associations and are potentially important to help understand disease processes. We performed a genome-wide scan for these 93 phenotypes in InCHIANTI. We identified 21 signals and 33 signals that reached P<5×10(-8) based on HapMap and 1000 Genomes imputation, respectively, and 9 and 11 that reached a stricter, likely conservative, threshold of P<5×10(-11) respectively. Imputation of 1000 Genomes genotype data modestly improved the strength of known associations. Of 20 associations detected at P<5×10(-8) in both analyses (17 of which represent well replicated signals in the NHGRI catalogue), six were captured by the same index SNP, five were nominally more strongly associated in 1000 Genomes imputed data and one was nominally more strongly associated in HapMap imputed data. We also detected an association between a low frequency variant and phenotype that was previously missed by HapMap based imputation approaches. An association between rs112635299 and alpha-1 globulin near the SERPINA gene represented the known association between rs28929474 (MAF = 0.007) and alpha1-antitrypsin that predisposes to emphysema (P = 2.5×10(-12)). Our data provide important proof of principle that 1000 Genomes imputation will detect novel, low frequency-large effect associations

A Relativistic Thomas-Fermi Description of Collective Modes in Droplets of Nuclear Matter

Isoscalar collective modes in a relativistic meson-nucleon system are investigated in the framework of the time-dependent Thomas-Fermi method. The energies of the collective modes are determined by solving consistently the dispersion relations and the boundary conditions. The energy weighted sum rule satisfied by the model allows the identification of the giant ressonances. The percentage of the energy weighted sum rule exhausted by the collective modes is in agreement with experimental data, but the energies come too high.Comment: 21 pages (RevTex) and 2 postscript figures as a compressed uuencode fil

Two's Company, Three's a Crowd: Experimental Evaluation of the Evolutionary Maintenance of Trioecy in Mercurialis annua (Euphorbiaceae)

Trioecy is an uncommon sexual system in which males, females, and hermaphrodites co-occur as three clearly different gender classes. The evolutionary stability of trioecy is unclear, but would depend on factors such as hermaphroditic sex allocation and rates of outcrossing vs. selfing. Here, trioecious populations of Mercurialis annua are described for the first time. We examined the frequencies of females, males and hermaphrodites across ten natural populations and evaluated the association between the frequency of females and plant densities. Previous studies have shown that selfing rates in this species are density-dependent and are reduced in the presence of males, which produce substantially more pollen than hermaphrodites. Accordingly, we examined the evolutionary stability of trioecy using an experiment in which we (a) indirectly manipulated selfing rates by altering plant densities and the frequency of males in a fully factorial manner across 20 experimental plots and (b) examined the effect of these manipulations on the frequency of the three sex phenotypes in the next generation of plants. In the parental generation, we measured the seed and pollen allocations of hermaphrodites and compared them with allocations by unisexual plants. In natural populations, females occurred at higher frequencies in denser patches, a finding consistent with our expectations. Under our experimental conditions, however, no combination of plant densities and male frequencies was associated with increased frequencies of females. Our results suggest that the factors that regulate female frequencies in trioecious populations of M. annua are independent of those regulating male frequencies (density), and that the stable co-existence of all three sex phenotypes within populations is unlikely