937 research outputs found
Genetic differentiation of spring-spawning and fall-spawning male Atlantic sturgeon in the James River, Virginia
Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae) populations are currently at severely depleted levels due to historic overfishing, habitat loss, and pollution. The importance of biologically correct stock structure for effective conservation and management efforts is well known. Recent improvements in our understanding of Atlantic sturgeon migrations, movement, and the occurrence of putative dual spawning groups leads to questions regarding the true stock structure of this endangered species. In the James River, VA specifically, captures of spawning Atlantic sturgeon and accompanying telemetry data suggest there are two discrete spawning groups of Atlantic sturgeon. The two putative spawning groups were genetically evaluated using a powerful microsatellite marker suite to determine if they are genetically distinct. Specifically, this study evaluates the genetic structure, characterizes the genetic diversity, estimates effective population size, and measures inbreeding of Atlantic sturgeon in the James River. The results indicate that fall and spring spawning James River Atlantic sturgeon groups are genetically distinct (overall FST = 0.048, FâST = 0.181) with little admixture between the groups. The observed levels of genetic diversity and effective population sizes along with the lack of detected inbreeding all indicated that the James River has two genetically healthy populations of Atlantic sturgeon. The study also demonstrates that samples from adult Atlantic sturgeon, with proper sample selection criteria, can be informative when creating reference population databases. The presence of two genetically-distinct spawning groups of Atlantic sturgeon within the James River raises concerns about the current genetic assignment used by managers. Other nearby rivers may also have dual spawning groups that either are not accounted for or are pooled in reference databases. Our results represent the second documentation of genetically distinct dual spawning groups of Atlantic sturgeon in river systems along the U.S. Atlantic coast, suggesting that current reference population database should be updated to incorporate both new samples and our increased understanding of Atlantic sturgeon life history
Theoretical Sensitivity Analysis for Quantitative Operational Risk Management
We study the asymptotic behavior of the difference between the values at risk
VaR(L) and VaR(L+S) for heavy tailed random variables L and S for application
in sensitivity analysis of quantitative operational risk management within the
framework of the advanced measurement approach of Basel II (and III). Here L
describes the loss amount of the present risk profile and S describes the loss
amount caused by an additional loss factor. We obtain different types of
results according to the relative magnitudes of the thicknesses of the tails of
L and S. In particular, if the tail of S is sufficiently thinner than the tail
of L, then the difference between prior and posterior risk amounts VaR(L+S) -
VaR(L) is asymptotically equivalent to the expectation (expected loss) of S.Comment: 21 pages, 1 figure, 4 tables, forthcoming in International Journal of
Theoretical and Applied Finance (IJTAF
Confirmation of two extended objects along the line of sight to PKS1830-211 with ESO-VLT adaptive optics imaging
We report on new high-resolution near-infrared images of the gravitationally
lensed radio source PKS1830-211, a quasar at z=2.507. These adaptive optics
observations, taken with the Very Large Telescope (VLT), are further improved
through image deconvolution. They confirm the presence of a second object along
the line of sight to the quasar, in addition to the previously known spiral
galaxy. This additional object is clearly extended in our images. However, its
faint luminosity does not allow to infer any photometric redshift. If this
galaxy is located in the foreground of PKS1830-211, it complicates the modeling
of this system and decreases the interest in using PKS1830-211 as a means to
determine H0 via the time delay between the two lensed images of the quasar.Comment: Accepted in A&A Letter
Recommended from our members
Fall 1969
Massachusetts Lawn and Turf Grass CouncilBetter Turf Through Research and Education Artificial Turf Faces Credibility Gab by Dr. Gene C. Nutter (page 1) Nitrogen Facts and Fallacies by W.H. Garman (2) DDT Opponents by Charles Wurster, Jr. (10) DDT Defenders by Charles Wurster, Jr. (11) What Type 2,4-D to Use? by J.S. Coartney and A.H. Kates (21) Irrigation Circuit Break Pinpointed in One Hour (24
Ecological Role of Blue Catfish in Chesapeake Bay Communities and Implications for Management
Rapid increase in abundance and expanded distribution of introduced blue catfish Ictalurus furcatus populations in the Chesapeake Bay watershed have raised regional management concerns. This study uses information from multiple surveys to examine expansion of blue catfish populations and document their role in tidal river communities. Originally stocked in the James, York, and Rappahannock River systems for development of commercial and recreational fisheries, blue catfish have now been documented in adjacent rivers and have expanded their within-river distribution to oligo- and mesohaline environments. Range expansions coincided with periods of peak abundance in 1996 and 2003 and with the concurrent decline in abundance of native white catfish I. catus. Blue catfish in these systems use a diverse prey base; various amphipod species typically dominate the diet of smaller individuals ([FL]), and fishes are common prey for larger blue catfish (\u3e300 mm FL). Recent studies based on stable isotope analyses suggest that adult blue catfish in these systems are apex predators that feed extensively on important fishery resources, including anadromous shads and herrings Alosa spp. and juvenile Atlantic menhaden Brevoortia tyrannus. Minimizing effects on Chesapeake Bay communities by controlling high densities of blue catfish populations is a primary goal of management, but conflicting demands of the commercial and recreational sectors must be resolved. Further, low market demand and human consumption concerns associated with purported accumulation of contaminants in blue catfish pose additional complications for regulating these fisheries.https://scholarworks.wm.edu/vimsbooks/1009/thumbnail.jp
Burnout in the ICU : potential consequences for staff and patient well-being
Peer reviewedAuthor versio
Assessment of Critical Habitats for Recovering the Chesapeake Bay Atlantic Sturgeon Distinct Population Segment
The states of Virginia and Maryland along with Virginia Commonwealth University (VCU), Virginia Institute of Marine Science (VIMS) and University of Maryland Center for Environmental Science (UMCES) partnered to assess critical habitat for recovering the Chesapeake Bay Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) distinct population segment. The primary objectives were to assess reproductive habitat in the James River, nursery habitat in the James and York Rivers and the degree of dependence of those populations to habitat in the Chesapeake Bay
Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous).
Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ? Palaeoscyllium sp., Prohaploblepharus riegrafi (MĂźller, 1989) gen. nov., ? Cretascyliorhinus sp., Scyliorhinidae inc. sedis 1, Scyliorhinidae inc. sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ? Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae, and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed
Change in treatment coverage and barriers to mental health care among adults with depression and alcohol use disorder: a repeat cross sectional community survey in Nepal
Abstract
Background
Despite the availability of evidence-based treatment, there is a substantial gap between the number of individuals in need of mental health care and those who receive treatment. The aim of this study was to assess changes in treatment coverage and barriers to mental health care among adults with depression and alcohol use disorder (AUD) before and after implementation of a district mental health care plan (MHCP) in Nepal.
Methods
The repeat population-based cross-sectional community survey was conducted with randomly selected adults in the baseline (Nâ=â1983) and the follow-up (Nâ=â1499) surveys, 3âyears and 6âmonths apart. The Patient Health Questionnaire and Alcohol Use Disorder Identification Test were used to screen people with probable depression and AUD. Barriers to seeking mental health care were assessed by using a standardized tool, the Barriers to Care Evaluation Scale (BACE).
Results
The proportion of the participants receiving treatment for depression increased by 3.7 points (from 8.1% in the baseline to 11.8% in the follow-up) and for AUD by 5.2 points (from 5.1% in the baseline to 10.3% in the follow-up study), however, these changes were not statistically significant. There was no significant reduction in the overall BACE score in both unadjusted and adjusted models for both depression and AUD. The possible reasons for non-significant changes in treatment coverage and barriers to care could be that (i) the method of repeat population level surveys with a random sample was too distal to the intervention to be able to register a change and (ii) the study was underpowered to detect such changes.
Conclusion
The study found non-significant trends for improvements in treatment coverage and barriers to mental health care following implementation of the district mental health care plan. The key areas for improvement in the current strategy to improve treatment coverage and barriers to mental health care included change in the content of the existing community sensitization program, particularly for changing attitude and intention of people with mental illness for seeking care
- âŚ