72,763 research outputs found
Data requirements for in-flight synthesis and multiple blender studies
Data requirements for in-flight synthesis and multiple blender studies to improve stability and control of large flexible booster
Electron scattering and transport in liquid argon
The transport of excess electrons in liquid argon driven out of equilibrium
by an applied electric field is revisited using a multi-term solution of
Boltzmann's equation together with ab initio liquid phase cross-sections
calculated using the Dirac-Fock scattering equations. The calculation of liquid
phase cross-sections extends previous treatments to consider multipole
polarisabilities and a non-local treatment of exchange while the accuracy of
the electron-argon potential is validated through comparison of the calculated
gas phase cross-section with experiment. The results presented highlight the
inadequacy of local treatments of exchange that are commonly used in liquid and
cluster phase cross-section calculations. The multi-term Boltzmann equation
framework accounting for coherent scattering enables the inclusion of the full
anisotropy in the differential cross-section arising from the interaction and
the structure factor, without an a priori assumption of quasi-isotropy in the
velocity distribution function. The model, which contains no free parameters
and accounts for both coherent scattering and liquid phase screening effects,
was found to reproduce well the experimental drift velocities and
characteristic energies.Comment: 32 pages, 16 figures; minor corrections, added 1 figur
Resolving the virial discrepancy in clusters of galaxies with modified Newtonian dynamics
A sample of 197 X-ray emitting clusters of galaxies is considered in the
context of Milgrom's modified Newtonian dynamics (MOND). It is shown that the
gas mass, extrapolated via an assumed model to a fixed radius of 3 Mpc,
is correlated with the gas temperature as predicted by MOND (). The observed temperatures are generally consistent with the inferred
mass of hot gas; no substantial quantity of additional unseen matter is
required in the context of MOND. However, modified dynamics cannot resolve the
strong lensing discrepancy in those clusters where this phenomenon occurs. The
prediction is that additional baryonic matter may be detected in the central
regions of rich clusters.Comment: Submitted to A&A, 4 pages, 3 figures, A&A macro
Recommended from our members
Assessment of sexual difficulties associated with multi-modal treatment for cervical or endometrial cancer: A systematic review of measurement instruments
Background: Practitioners and researchers require an outcome measure that accurately identifies the range of common treatment-induced changes in sexual function and well-being experienced by women after cervical or endometrial cancer. This systematic review critically appraised the measurement properties and clinical utility of instruments validated for the measurement of female sexual dysfunction (FSD) in this clinical population.
Methods: A bibliographic database search for questionnaire development or validation papers was completed and methodological quality and measurement properties of selected studies rated using the Consensus-based Standards for the selection of health Measurement Instrument (COSMIN) checklist.
Results: 738 articles were screened, 13 articles retrieved for full text assessment and 7 studies excluded, resulting in evaluation of 6 papers; 2 QoL and 4 female sexual morbidity measures.
Five of the six instruments omitted one or more dimension of female sexual function and only one instrument explicitly measured distress associated with sexual changes as per DSM V (APA 2013) diagnostic criteria.
None of the papers reported measurement error, responsiveness data was available for only two instruments, three papers failed to report on criterion validity, and test-retest reliability reporting was inconsistent. Heterosexual penile-vaginal intercourse remains the dominant sexual activity focus for sexual morbidity PROMS terminology and instruments lack explicit reference to solo or non-coital sexual expression or validation in a non-heterosexual sample. Four out of six instruments included mediating treatment or illness items such as vaginal changes, menopause or altered body image.
Conclusions: Findings suggest that the Female Sexual Function Index (FSFI) remains the most robust sexual morbidity outcome measure, for research or clinical use, in sexually active women treated for cervical or endometrial cancer
Support for Integrated Ecosystem Assessments of NOAA’s National Estuarine Research Reserves System (NERRS), Volume I: The Impacts of Coastal Development on the Ecology and Human Well-being of Tidal Creek Ecosystems of the US Southeast
A study was conducted, in association with the Sapelo Island and North Carolina National Estuarine Research Reserves (NERRs), to evaluate the impacts of coastal development on sentinel habitats (e.g., tidal creek ecosystems), including potential impacts to human health and well-being. Uplands associated with southeastern tidal creeks and the salt marshes they drain are popular locations for building homes, resorts, and recreational facilities because of the high quality of life and mild climate associated with these environments. Tidal creeks form part of the estuarine ecosystem characterized by high biological productivity, great ecological value, complex environmental gradients, and numerous interconnected processes. This research combined a watershed-level study integrating ecological, public health and human dimension attributes with watershed-level land use data. The approach used for this research was based upon a comparative watershed and ecosystem approach that sampled tidal creek networks draining developed watersheds (e.g., suburban, urban, and industrial) as well as undeveloped sites. The primary objective of this work was to clearly define the relationships between coastal development with its concomitant land use changes and non-point source pollution loading and the ecological and human health and well-being status of tidal creek ecosystems.
Nineteen tidal creek systems, located along the southeastern United States coast from southern North Carolina to southern Georgia, were sampled during summer (June-August), 2005 and 2006. Within each system, creeks were divided into two primary segments based upon tidal zoning: intertidal (i.e., shallow, narrow headwater sections) and subtidal (i.e., deeper and wider sections), and watersheds were delineated for each segment. In total, we report findings on 24 intertidal and 19 subtidal creeks. Indicators sampled throughout each creek included water quality (e.g., dissolved oxygen concentration, salinity, nutrients, chlorophyll-a levels), sediment quality (e.g., characteristics, contaminants levels including emerging contaminants), pathogen and viral indicators, and abundance and genetic responses of biological resources (e.g., macrobenthic and nektonic communities, shellfish tissue contaminants, oyster microarray responses).
For many indicators, the intertidally-dominated or headwater portions of tidal creeks were found to respond differently than the subtidally-dominated or larger and deeper portions of tidal creeks. Study results indicate that the integrity and productivity of headwater tidal creeks were impaired by land use changes and associated non-point source pollution, suggesting these habitats are valuable early warning sentinels of ensuing ecological impacts and potential public health threats. For these headwater creeks, this research has assisted the validation of a previously developed conceptual model for the southeastern US region. This conceptual model identified adverse changes that generally occurred in the physical and chemical environment (e.g., water quality indicators such as indicator bacteria for sewage pollution or sediment chemical contamination) when impervious cover levels in the watershed reach 10-20%. Ecological characteristics responded and were generally impaired when impervious cover levels exceed 20-30%. Estimates of impervious cover levels defining where human uses are impaired are currently being determined, but it appears that shellfish bed closures and the flooding vulnerability of headwater regions become a concern when impervious cover values exceed 10-30%. This information can be used to forecast the impacts of changing land use patterns on tidal creek environmental quality as well as associated human health and well-being. In addition, this study applied tools and technologies that are adaptable, transferable, and repeatable among the high quality NERRS sites as comparable reference entities to other nearby developed coastal watersheds. The findings herein will be of value in addressing local, regional and national needs for understanding multiple stressor (anthropogenic and human impacts) effects upon estuarine ecosystems and response trends in ecosystem condition with changing coastal impacts (i.e., development, climate change). (PDF contaions 88 pages
Recommended from our members
CCH <i>N</i> = 4-3 emission from dense interstellar clouds
The authors have searched for N = 4 - 3 rotational line emission from the ethynyl radical CCH, at 349 GHz toward a number of galactic molecular clouds. They have detected emission from ten giant molecular clouds and have derived CCH column densities on the order of 1014 - 1015cm-2. They find that CCH emission arises from dense gas, n(H2) ~ 104 - 105cm-3, but not from very dense material, n(H2) > 106cm-3, nor from hot gas such as the "hot core" region in Orion
Target enrichment of ultraconserved elements from arthropods provides a genomic perspective on relationships among Hymenoptera
Gaining a genomic perspective on phylogeny requires the collection of data
from many putatively independent loci collected across the genome. Among
insects, an increasingly common approach to collecting this class of data
involves transcriptome sequencing, because few insects have high-quality genome
sequences available; assembling new genomes remains a limiting factor; the
transcribed portion of the genome is a reasonable, reduced subset of the genome
to target; and the data collected from transcribed portions of the genome are
similar in composition to the types of data with which biologists have
traditionally worked (e.g., exons). However, molecular techniques requiring RNA
as a template are limited to using very high quality source materials, which
are often unavailable from a large proportion of biologically important insect
samples. Recent research suggests that DNA-based target enrichment of conserved
genomic elements offers another path to collecting phylogenomic data across
insect taxa, provided that conserved elements are present in and can be
collected from insect genomes. Here, we identify a large set (n1510) of
ultraconserved elements (UCE) shared among the insect order Hymenoptera. We use
in silico analyses to show that these loci accurately reconstruct relationships
among genome-enabled Hymenoptera, and we design a set of baits for enriching
these loci that researchers can use with DNA templates extracted from a variety
of sources. We use our UCE bait set to enrich an average of 721 UCE loci from
30 hymenopteran taxa, and we use these UCE loci to reconstruct phylogenetic
relationships spanning very old (220 MYA) to very young (1 MYA)
divergences among hymenopteran lineages. In contrast to a recent study
addressing hymenopteran phylogeny using transcriptome data, we found ants to be
sister to all remaining aculeate lineages with complete support
- …