390 research outputs found
Radio observations of the planetary nebula around the OH/IR Star OH354.88-0.54 (V1018 Sco)
We present radio observations of the unique, recently formed, planetary
nebula (PN) associated with a very long-period OH/IR variable star V1018 Sco
that is unequivocally still in its asymptoticgiant branch phase. Two regions
within the optical nebula are clearly detected in nonthermal radio continuum
emission, with radio spectral indices comparable to those seen in
colliding-wind Wolf-Rayet binaries. We suggest that these represent shocked
interactions between the hot, fast stellar wind and the cold nebular shell that
represents the PN's slow wind moving away from the central star. This same
interface produces both synchrotron radio continuum and the optical PN
emission. The fast wind is neither spherical in geometry nor aligned withany
obvious optical or radio axis. We also report the detection of transient H2O
maser emission in this nebula.Comment: 11 pages, LaTeX (mn2e.cls), incl. 9 PostScript (ps or eps) figures
and 2 tables. Accepted by MNRA
Amplification of Earthquake Ground Motions in Washington, DC, and Implications for Hazard Assessments in Central and Eastern North America
The extent of damage in Washington, DC, from the 2011 MW 5.8 Mineral, VA, earthquake was surprising for an epicenter 130 km away; U.S. Geological Survey “Did-You-Feel-It” reports suggest that Atlantic Coastal Plain and other unconsolidated sediments amplified ground motions in the city. We measure this amplification relative to bedrock sites using earthquake signals recorded on a temporary seismometer array. The spectral ratios show strong amplification in the 0.7 to 4 Hz frequency range for sites on sediments. This range overlaps with resonant frequencies of buildings in the city as inferred from their heights, suggesting amplification at frequencies to which many buildings are vulnerable to damage. Our results emphasize that local amplification can raise moderate ground motions to damaging levels in stable continental regions, where low attenuation extends shaking levels over wide areas and unconsolidated deposits on crystalline metamorphic or igneous bedrock can result in strong contrasts in near-surface material properties
Operative <i>versus </i>conservative management for inguinal hernia:a methodology scoping review of randomized controlled trials
Introduction: There is a lack of consensus on the management of inguinal hernia with limited symptoms. To address this issue a systematic review of existing randomized clinical trials (RCTs) was performed to critically appraise all existing data on asymptomatic hernia management, focusing on generalizability. Methods: A scoping review to identify all RCTs comparing surgical and conservative management of patients with inguinal hernias was undertaken. Medline, Embase, Cochrane and ClinicalTrials.gov databases were searched. Data collected included study characteristics and definitions of population, intervention/comparator, and outcomes; and limitations of each study were also extracted. The quality and generalizability of included RCTs were evaluated using Cochrane’s ROB-2 and the PRECIS-2 tool, respectively. Results: Searches returned 661 papers; 14 full-text papers were assessed and three RCTs were identified. All RCTs included only male patients with a mean age above 55 years. All RCTs included asymptomatic patients and two included those with minimal symptoms. Different definitions for ‘minimally symptomatic’ were used in RCTs and none provided details of what was meant by conservative treatment. Follow-up periods varied between studies (1, 2, 3 years). All RCTs had an overall high risk of bias. According to PRECIS-2, two RCTs were classified as pragmatic, and one was equally pragmatic and explanatory. Discussion: This systematic review highlights a high risk of bias but a good generalizability of the findings from the RCTs conducted on minimally symptomatic inguinal hernia patients. To improve the guidelines for the management of this group of patients, more generalizable data are needed
Operative <i>versus </i>conservative management for inguinal hernia:a methodology scoping review of randomized controlled trials
Introduction: There is a lack of consensus on the management of inguinal hernia with limited symptoms. To address this issue a systematic review of existing randomized clinical trials (RCTs) was performed to critically appraise all existing data on asymptomatic hernia management, focusing on generalizability. Methods: A scoping review to identify all RCTs comparing surgical and conservative management of patients with inguinal hernias was undertaken. Medline, Embase, Cochrane and ClinicalTrials.gov databases were searched. Data collected included study characteristics and definitions of population, intervention/comparator, and outcomes; and limitations of each study were also extracted. The quality and generalizability of included RCTs were evaluated using Cochrane’s ROB-2 and the PRECIS-2 tool, respectively. Results: Searches returned 661 papers; 14 full-text papers were assessed and three RCTs were identified. All RCTs included only male patients with a mean age above 55 years. All RCTs included asymptomatic patients and two included those with minimal symptoms. Different definitions for ‘minimally symptomatic’ were used in RCTs and none provided details of what was meant by conservative treatment. Follow-up periods varied between studies (1, 2, 3 years). All RCTs had an overall high risk of bias. According to PRECIS-2, two RCTs were classified as pragmatic, and one was equally pragmatic and explanatory. Discussion: This systematic review highlights a high risk of bias but a good generalizability of the findings from the RCTs conducted on minimally symptomatic inguinal hernia patients. To improve the guidelines for the management of this group of patients, more generalizable data are needed
Global Phylogeography of the Dusky Shark Carcharhinus obscurus: Implications for Fisheries Management and Monitoring the Shark Fin Trade
Genetic stock structure information is needed to delineate management units and monitor trade in sharks, many of which are heavily exploited and declining. The dusky shark Carcharhinus obscurus is a large apex predator that is sought after for its fins and is considered highly susceptible to overexploitation. The International Union for the Conservation of Nature (IUCN) classifies this species as ‘Vulnerable’ globally and ‘Endangered’ in the northwest Atlantic. We make the first assessment of global stock structure of C. obscurus by analyzing part of the mitochondrial control region (mtCR) in 255 individuals sampled from 8 geographically dispersed locations. We found 25 mtCR haplotypes and rejected a null hypothesis of panmixia (analysis of molecular variance, ΦST = 0.55, p \u3c 0.000001), detecting significant differentiation between 3 management units: US Atlantic (USATL), South Africa (SAF), and Australia (AUS). We also found preliminary evidence of population structure between the USATL and southwest Atlantic (Brazil). There were no shared haplotypes between the western Atlantic and Indo-Pacific. These analyses suggest that replenishment of the collapsed USATL management unit via immigration of females from elsewhere is unlikely. Mixed stock analysis (MSA) simulations show that reconstruction of the relative contributions of USATL, SAF, and AUS management units to the Asian fin trade is possible using these mtCR sequences. We suggest avenues for obtaining samples to conduct MSA of the shark fin trade, which could enhance management of dusky sharks and other species that are exploited for their fins
Making waves. Bridging theory and practice towards multiple stressor management in freshwater ecosystems
Embargo until February 26, 2023Despite advances in conceptual understanding, single-stressor abatement approaches remain common in the management of fresh waters, even though they can produce unexpected ecological responses when multiple stressors interact. Here we identify limitations restricting the development of multiple-stressor management strategies and address these, bridging theory and practice, within a novel empirical framework. Those critical limitations include that (i) monitoring schemes fall short of accounting for theory on relationships between multiple-stressor interactions and ecological responses, (ii) current empirical modelling approaches neglect the prevalence and intensity of multiple-stressor interactions, and (iii) mechanisms of stressor interactions are often poorly understood. We offer practical recommendations for the use of empirical models and experiments to predict the effects of freshwater degradation in response to changes in multiple stressors, demonstrating this approach in a case study. Drawing on our framework, we offer practical recommendations to support the development of effective management strategies in three general multiple-stressor scenarios.acceptedVersio
Glucocorticoids regulate mitochondrial fatty acid oxidation in fetal cardiomyocytes
Abstract: The late gestational rise in glucocorticoids contributes to the structural and functional maturation of the perinatal heart. Here, we hypothesized that glucocorticoid action contributes to the metabolic switch in perinatal cardiomyocytes from carbohydrate to fatty acid oxidation. In primary mouse fetal cardiomyocytes, dexamethasone treatment induced expression of genes involved in fatty acid oxidation and increased mitochondrial oxidation of palmitate, dependent upon a glucocorticoid receptor (GR). Dexamethasone did not, however, induce mitophagy or alter the morphology of the mitochondrial network. In vivo, in neonatal mice, dexamethasone treatment induced cardiac expression of fatty acid oxidation genes. However, dexamethasone treatment of pregnant C57Bl/6 mice at embryonic day (E)13.5 or E16.5 failed to induce fatty acid oxidation genes in fetal hearts assessed 24 h later. Instead, at E17.5, fatty acid oxidation genes were downregulated by dexamethasone, as was GR itself. PGC-1α, required for glucocorticoid-induced maturation of primary mouse fetal cardiomyocytes in vitro, was also downregulated in fetal hearts at E17.5, 24 h after dexamethasone administration. Similarly, following a course of antenatal corticosteroids in a translational sheep model of preterm birth, both GR and PGC-1α were downregulated in heart. These data suggest that endogenous glucocorticoids support the perinatal switch to fatty acid oxidation in cardiomyocytes through changes in gene expression rather than gross changes in mitochondrial volume or mitochondrial turnover. Moreover, our data suggest that treatment with exogenous glucocorticoids may interfere with normal fetal heart maturation, possibly by downregulating GR. This has implications for clinical use of antenatal corticosteroids when preterm birth is considered a possibility. Key points: Glucocorticoids are steroid hormones that play a vital role in late pregnancy in maturing fetal organs, including the heart. In fetal cardiomyocytes in culture, glucocorticoids promote mitochondrial fatty acid oxidation, suggesting they facilitate the perinatal switch from carbohydrates to fatty acids as the predominant energy substrate. Administration of a synthetic glucocorticoid in late pregnancy in mice downregulates the glucocorticoid receptor and interferes with the normal increase in genes involved in fatty acid metabolism in the heart. In a sheep model of preterm birth, antenatal corticosteroids (synthetic glucocorticoid) downregulates the glucocorticoid receptor and the gene encoding PGC-1α, a master regulator of energy metabolism. These experiments suggest that administration of antenatal corticosteroids in anticipation of preterm delivery may interfere with fetal heart maturation by downregulating the ability to respond to glucocorticoids
HIV Infection Linked to Injection Use of Oxymorphone in Indiana, 2014-2015
BACKGROUND: In January 2015, a total of 11 new diagnoses of human immunodeficiency virus (HIV) infection were reported in a small community in Indiana. We investigated the extent and cause of the outbreak and implemented control measures.
METHODS: We identified an outbreak-related case as laboratory-confirmed HIV infection newly diagnosed after October 1, 2014, in a person who either resided in Scott County, Indiana, or was named by another case patient as a syringe-sharing or sexual partner. HIV polymerase (pol) sequences from case patients were phylogenetically analyzed, and potential risk factors associated with HIV infection were ascertained.
RESULTS: From November 18, 2014, to November 1, 2015, HIV infection was diagnosed in 181 case patients. Most of these patients (87.8%) reported having injected the extended-release formulation of the prescription opioid oxymorphone, and 92.3% were coinfected with hepatitis C virus. Among 159 case patients who had an HIV type 1 pol gene sequence, 157 (98.7%) had sequences that were highly related, as determined by phylogenetic analyses. Contact tracing investigations led to the identification of 536 persons who were named as contacts of case patients; 468 of these contacts (87.3%) were located, assessed for risk, tested for HIV, and, if infected, linked to care. The number of times a contact was named as a syringe-sharing partner by a case patient was significantly associated with the risk of HIV infection (adjusted risk ratio for each time named, 1.9; P<0.001). In response to this outbreak, a public health emergency was declared on March 26, 2015, and a syringe-service program in Indiana was established for the first time.
CONCLUSIONS: Injection-drug use of extended-release oxymorphone within a network of persons who inject drugs in Indiana led to the introduction and rapid transmission of HIV. (Funded by the state government of Indiana and others.)
Gaps and opportunities in refractory status epilepticus research in children: A multi-center approach by the Pediatric Status Epilepticus Research Group (pSERG)
PURPOSE:
Status epilepticus (SE) is a life-threatening condition that can be refractory to initial treatment. Randomized controlled studies to guide treatment choices, especially beyond first-line drugs, are not available. This report summarizes the evidence that guides the management of refractory convulsive SE (RCSE) in children, defines gaps in our clinical knowledge and describes the development and works of the \u27pediatric Status Epilepticus Research Group\u27 (pSERG). METHODS:
A literature review was performed to evaluate current gaps in the pediatric SE and RCSE literature. In person and online meetings helped to develop and expand the pSERG network. RESULTS:
The care of pediatric RCSE is largely based on extrapolations of limited evidence derived from adult literature and supplemented with case reports and case series in children. No comparative effectiveness trials have been performed in the pediatric population. Gaps in knowledge include risk factors for SE, biomarkers of SE and RCSE, second- and third-line treatment options, and long-term outcome. CONCLUSION:
The care of children with RCSE is based on limited evidence. In order to address these knowledge gaps, the multicenter pSERG was established to facilitate prospective collection, analysis, and sharing of de-identified data and biological specimens from children with RCSE. These data will allow identification of treatment strategies associated with better outcomes and delineate evidence-based interventions to improve the care of children with SE
Do Fruit Nutrients Affect Subgrouping Patterns in Wild Spider Monkeys (Ateles geoffroyi)?
One of the main costs of group living is feeding competition. Fission–fusion dynamics are thought to be a strategy to avoid overt competition for food resources. We tested whether food abundance and quality affected such dynamics in a species characterized by a high degree of fission–fusion dynamics. We collected data on 22 adult and subadult spider monkeys (Ateles geoffroyi) living in a large community in the protected area of Otoch Ma’ax Yetel Kooh, Yucatan, Mexico. We recorded subgroup size and fission events as well as fruit abundance during 12 mo and conducted nutritional analyses on the fruit species that the study subjects consumed most. We found no effect of fruit abundance or nutritional quality of recently visited food patches on individual fission decisions, but the amount of protein in the food patches visited over the course of the day was a good predictor of subgroup size. While the absence of support for a relationship between fruit characteristics and fission decisions may be due to the short temporal scale of the analysis, our findings relating subgroup size to the amount of protein in the visited food patches over the course of the day may be explained by individual spider monkeys attempting to obtain sufficient protein intake from their fruit-based diet. © 2016 Springer Science+Business Media New Yor
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