586 research outputs found
Military Sexual Trauma and Department of Veterans Affairs Disability Compensation for PTSD: Barriers, Evidentiary Burdens and Potential Remedies
Economic-Environmental Tradeoffs: Methodologies for Analysis of the Agricultural Production-Rural Environment System
Undesirable environmental impacts of agricultural production are becoming more numerous as agricultural production is increased to meet world food demands. The question of environmental controls on agriculture has many implications on both the level of output from agriculture and upon the quality of the environment. The purposes of this paper are to: (1) define a general structure for the agricultural production-rural environment system, (2) define a general analytical framework for management of the system; and (3) describe an empirical management study of water quality and erosion control.
The following paper represents the contributions of a group of experts from the U.S. Department of Agriculture to the collaborative study with IIASA's task, "Environmental Problems of Agriculture." The study, culminating in this paper, met one of the Task's research objectives, which as stated in the Research Plan is, "an evaluation of the trade-offs between the intensification of agricultural production and the possible deterioration in environmental quality." The authors further present, in condensed form, an example demonstrating how a highly complex environmental problem can be analyzed. The methodology used for this analysis is not restricted to the study of agricultural-environmental interactions; rather, it can be applied on a wider basis
Landscapes Of Silence At The First Baptist Church
The Historic Area of Colonial Williamsburg is often presented as a “town which time passed by” (Yetter 1988:30). This narrative implies that the museum landscape reflects the actual past and that restoration efforts simply returned the town to the way it used to be. However, the Restoration was accomplished according to specific ideological goals. Colonial Williamsburg was created as a shrine to traditionalist, conservative values (Greenspan 2002; Handler & Gable 1997; Lindgren 1989; Lindgren 1993) which are intrinsically linked to the global structure of systemic White supremacy. These values were enacted during the Restoration, as Black residents of the future Historic Area were underpaid for their property and displaced into segregated neighborhoods. They were also inscribed in the physical museum landscape and in the development of historic interpretation. In the past few decades, Colonial Williamsburg has attempted to bring silenced histories to light through increased dedication to African-American interpretation. Still, this history of erasure goes largely unacknowledged by the Foundation. In this thesis, I use the First Baptist Church as a case study to demonstrate how Black history was silenced by the Restoration and how an ongoing archaeological project works to resituate the site within the museum landscape. I discuss the history of the church from its founding in 1776 through the present day, with special emphasis on the displacement in 1957 and the tropes of silencing (Trouillot 2015 [1995]) utilized in the creation of the museum landscape. The installation of interpretive infrastructure adjacent to the site in the 1960s and 1990s recognized the historic significance of the First Baptist site while simultaneously continuing the erasure of Colonial Williamsburg’s role in the church’s destruction. The 2020-2023 archaeological project incorporates community voices in the (re)interpretation of the site and provides an opportunity for Colonial Williamsburg to acknowledge its own history of racism and dispossession
The spatial distribution of O-B5 stars in the solar neighborhood as measured by Hipparcos
We have developed a method to calculate the fundamental parameters of the
vertical structure of the Galaxy in the solar neighborhood from trigonometric
parallaxes alone. The method takes into account Lutz-Kelker-type biases in a
self-consistent way and has been applied to a sample of O-B5 stars obtained
from the Hipparcos catalog. We find that the Sun is located 24.2 +/- 1.7
(random) +/- 0.4 (systematic) pc above the galactic plane and that the disk
O-B5 stellar population is distributed with a scale height of 34.2 +/- 0.8
(random) +/- 2.5 (systematic) pc and an integrated surface density of (1.62 +/-
0.04 (random) +/- 0.14 (systematic)) 10^{-3} stars pc^{-2}. A halo component is
also detected in the distribution and constitutes at least ~5% of the total
O-B5 population. The O-B5 stellar population within ~100 pc of the Sun has an
anomalous spatial distribution, with a less-than-average number density. This
local disturbance is probably associated with the expansion of Gould's belt.Comment: 14 pages, 3 figures, to appear in the May 2001 issue of the
Astronomical Journa
Scatter broadening of pulsars in the direction of the Gum nebula
We have measured the scatter broadening of pulsars in the direction of the
Gum nebula. For the first time, our observations show clear variations of
scattering properties across the Gum nebula. The IRAS-Vela shell is shown to be
a high scattering region. Our revised estimations of distances to these pulsars
are consistently less by a factor of 2--3, which has very important
consequences for the deduced values of radio luminosity and transverse velocity
of pulsars.Comment: Astronomy & Astrophysics, 2001, 370, 58
Optical Technologies for UV Remote Sensing Instruments
Over the last decade significant advances in technology have made possible development of instruments with substantially improved efficiency in the UV spectral region. In the area of optical coatings and materials, the importance of recent developments in chemical vapor deposited (CVD) silicon carbide (SiC) mirrors, SiC films, and multilayer coatings in the context of ultraviolet instrumentation design are discussed. For example, the development of chemically vapor deposited (CVD) silicon carbide (SiC) mirrors, with high ultraviolet (UV) reflectance and low scatter surfaces, provides the opportunity to extend higher spectral/spatial resolution capability into the 50-nm region. Optical coatings for normal incidence diffraction gratings are particularly important for the evolution of efficient extreme ultraviolet (EUV) spectrographs. SiC films are important for optimizing the spectrograph performance in the 90 nm spectral region. The performance evaluation of the flight optical components for the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument, a spectroscopic instrument to fly aboard the Solar and Heliospheric Observatory (SOHO) mission, designed to study dynamic processes, temperatures, and densities in the plasma of the upper atmosphere of the Sun in the wavelength range from 50 nm to 160 nm, is discussed. The optical components were evaluated for imaging and scatter in the UV. The performance evaluation of SOHO/CDS (Coronal Diagnostic Spectrometer) flight gratings tested for spectral resolution and scatter in the DGEF is reviewed and preliminary results on resolution and scatter testing of Space Telescope Imaging Spectrograph (STIS) technology development diffraction gratings are presented
Antitumor Activity of Selected Derivatives of Pyrazole- Benzenesulfonamides from Dilithiated C(α), N-Phenylhydrazones and Lithiated Methyl 2-(Aminosulfonyl)benzoate
Several pyrazole-benzenesulfonamides were subjected to biological evaluation involving tumor formation on potato discs caused by Agrobacterium tumefaciens. This assay led to some excellent and promising initial results with three of the pyrazole compounds showing increased tumor inhibition when compared to a recognized standard, camptothecin. The select pyrazole-benzenesulfonamides were prepared by condensation-cyclization of several dilithiated C(α),N-phenylhydrazones with lithiated methyl 2-aminosulfonyl-benzoate
Genetic differentiation of European grayling (Thymallus thymallus) populations in Serbia, based on mitochondrial and nuclear DNA analyses
<p>Abstract</p> <p>Background</p> <p>The structure and diversity of grayling (<it>Thymallus thymallus</it>) populations have been well studied in most of its native habitat; however the southernmost populations of the Balkan Peninsula remain largely unexplored. The purpose of this study was to assess the genetic diversity of Serbian grayling populations, detect the impact of stocking and provide guidelines for conservation and management.</p> <p>Methods</p> <p>Eighty grayling individuals were collected from four rivers (Ibar, Lim, Drina and Rzav). The mitochondrial DNA control region (CR; 595 bp of the 3'end and 74 bp of flanking tRNA) and the ATP6 gene (630 bp fragment) were sequenced for 20 individuals (five from each locality). In addition, all individuals were genotyped with 12 microsatellite loci. The diversity and structure of the populations as well as the recent and ancient population declines were studied using specialized software.</p> <p>Results</p> <p>We detected three new haplotypes in the mtDNA CR and four haplotypes in the ATP6 gene of which three had not been described before. Previously, one CR haplotype and two ATP6 gene haplotypes had been identified as allochthonous, originating from Slovenia. Reconstruction of phylogenetic relations placed the remaining two CR haplotypes from the River Danube drainage of Serbia into a new clade, which is related to the previously described sister Slovenian clade. These two clades form a new Balkan clade. Microsatellite marker analysis showed that all four populations are genetically distinct from each other without any sign of intra-population structure, although stocking of the most diverse population (Drina River) was confirmed by mtDNA analysis. Recent and historical population declines of Serbian grayling do not differ from those of other European populations.</p> <p>Conclusions</p> <p>Our study shows that (1) the Ibar, Lim and Drina Rivers grayling populations are genetically distinct from populations outside of Serbia and thus should be managed as native populations in spite of some introgression in the Drina River population and (2) the Rzav River population is not appropriate for further stocking activities since it originates from stocked Slovenian grayling. However, the Rzav River population does not represent an immediate danger to other populations because it is physically isolated from these.</p
A study of the neglected Galactic HII region NGC 2579 and its companion ESO 370-9
The Galactic HII region NGC 2579 has stayed undeservedly unexplored due to
identification problems which persisted until recently. Both NGC 2579 and its
companion ESO 370-9 have been misclassified as planetary or reflection nebula,
confused with each other and with other objects. Due to its high surface
brightness, high excitation, angular size of few arcminutes and relatively low
interstellar extinction, NGC 2579 is an ideal object for investigations in the
optical range. Located in the outer Galaxy, NGC 2579 is an excellent object for
studying the Galactic chemical abundance gradients. In this paper we present
the first comprehensive observational study on the nebular and stellar
properties of NGC 2579 and ESO 370-9, including the determination of electron
temperature, density structure, chemical composition, kinematics, distance, and
the identification and spectral classification of the ionizing stars, and
discuss the nature of ESO 370-9. Long slit spectrophotometric data in the
optical range were used to derive the nebular electron temperature, density and
chemical abundances and for the spectral classification of the ionizing star
candidates. Halpha and UBV CCD photometry was carried out to derive stellar
distances from spectroscopic parallax and to measure the ionizing photon flux.Comment: To be published in Astronomy & Astrophysic
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