1,644 research outputs found
On the Pressure Broadening in the Gamma Bands of Nitric Oxide
A quantitative investigation of the pressure broadening in the γ(0,0) and γ(1,0) bands of nitric acid established that the pressure effect is not abnormal as has sometimes been supposed and that the collision diameter of the excited NO molecule is approximately 3.8 Å
Selected tether applications in space: Phase 2. Executive summary
The application of tether technology has the potential to increase the overall performance efficiency and capability of the integrated space operations and transportation systems through the decade of the 90s. The primary concepts for which significant economic benefits were identified are dependent on the space station as a storage device for angular momentum and as an operating base for the tether system. Concepts examined include: (1) tether deorbit of shuttle from space station; (2) tethered orbit insertion of a spacecraft from shuttle; (3) tethered platform deployed from space station; (4) tether-effected rendezvous of an OMV with a returning OTV; (5) electrodynamic tether as an auxiliary power source for space station; and (6) tether assisted launch of an OTV mission from space station
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Role of Environmentally Induced Epigenetic Transgenerational Inheritance in Evolutionary Biology
The mid-twentieth century saw the incorporation of Mendelian genetics into Darwinian theories of evolution. This foundation, termed the modern evolutionary synthesis, has developed into the primary current paradigm of evolutionary biology. However, the current modern synthesis does not include a role for epigenetics in developmental modifications or any mechanisms of non-genetic inheritance. With the recent expansion of epigenetic research into non-genetic mechanisms of adaptation and inheritance, there is a need to expand the modern synthesis into a new extended evolutionary theory. The current chapter presents the role of environmentally induced epigenetic transgenerational inheritance in evolutionary biology
Low-Cost Air Quality Monitoring Tools: From Research to Practice (A Workshop Summary).
In May 2017, a two-day workshop was held in Los Angeles (California, U.S.A.) to gather practitioners who work with low-cost sensors used to make air quality measurements. The community of practice included individuals from academia, industry, non-profit groups, community-based organizations, and regulatory agencies. The group gathered to share knowledge developed from a variety of pilot projects in hopes of advancing the collective knowledge about how best to use low-cost air quality sensors. Panel discussion topics included: (1) best practices for deployment and calibration of low-cost sensor systems, (2) data standardization efforts and database design, (3) advances in sensor calibration, data management, and data analysis and visualization, and (4) lessons learned from research/community partnerships to encourage purposeful use of sensors and create change/action. Panel discussions summarized knowledge advances and project successes while also highlighting the questions, unresolved issues, and technological limitations that still remain within the low-cost air quality sensor arena
A systematic review of evidence to inform HIV prevention interventions among men who have sex with men in Europe.
An estimated 42% of all newly diagnosed HIV cases in Europe in 2013 were transmitted during sex between men. This review was performed to identify and describe studies evaluating the efficacy and effectiveness of HIV prevention interventions among men who have sex with men (MSM), in relation to implementation data from European settings. A systematic search was performed individually for 24 interventions.Data were extracted from studies including efficacy or implementation data from European settings,appraised for efficacy, implementation and plausibility, and assigned a grade (1-4) according to the Highest Attainable Standard of Evidence (HASTE)framework. Four interventions (condom use, peer outreach,peer-led groups, and using universal coverage of antiretroviral treatment and treatment as prevention)were assigned the highest HASTE grade, 1. Another four interventions were assigned 2a for probable recommendation, including voluntary counseling and testing for HIV, using condom-compatible lubricant,using post-exposure prophylaxis, and individual counselling for MSM living with HIV. In addition, seven interventions were assigned a grade of 2b, for possible recommendation. Encouragingly, 15 interventions were graded to be strongly, probably or possibly recommended.In the relatively resource-rich European setting, there is an opportunity to provide global leadership with regard to the regional scale-up of comprehensive HIV prevention interventions for MSM
Multi-serotype pneumococcal nasopharyngeal carriage prevalence in vaccine naïve Nepalese children, assessed using molecular serotyping.
Invasive pneumococcal disease is one of the major causes of death in young children in resource poor countries. Nasopharyngeal carriage studies provide insight into the local prevalence of circulating pneumococcal serotypes. There are very few data on the concurrent carriage of multiple pneumococcal serotypes. This study aimed to identify the prevalence and serotype distribution of pneumococci carried in the nasopharynx of young healthy Nepalese children prior to the introduction of a pneumococcal conjugate vaccine using a microarray-based molecular serotyping method capable of detecting multi-serotype carriage. We conducted a cross-sectional study of healthy children aged 6 weeks to 24 months from the Kathmandu Valley, Nepal between May and October 2012. Nasopharyngeal swabs were frozen and subsequently plated on selective culture media. DNA extracts of plate sweeps of pneumococcal colonies from these cultures were analysed using a molecular serotyping microarray capable of detecting relative abundance of multiple pneumococcal serotypes. 600 children were enrolled into the study: 199 aged 6 weeks to <6 months, 202 aged 6 months to < 12 months, and 199 aged 12 month to 24 months. Typeable pneumococci were identified in 297/600 (49.5%) of samples with more than one serotype being found in 67/297 (20.2%) of these samples. The serotypes covered by the thirteen-valent pneumococcal conjugate vaccine were identified in 44.4% of samples containing typeable pneumococci. Application of a molecular serotyping approach to identification of multiple pneumococcal carriage demonstrates a substantial prevalence of co-colonisation. Continued surveillance utilising this approach following the introduction of routine use of pneumococcal conjugate vaccinates in infants will provide a more accurate understanding of vaccine efficacy against carriage and a better understanding of the dynamics of subsequent serotype and genotype replacement
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Factors influencing population density of stream-living Redband Trout in southeast Oregon, USA
Fisheries managers often use models of population density to evaluate the status of stream-living fishes, but many of these models have low predictive performance for abundance and density. These models could incorporate several factors that can limit population density, particularly the effect of body size, envisioned by the theory of self-thinning. In addition, constraints imposed on density by physical and biological habitat conditions in streams are important to consider. In this study, we describe a two-phase approach to predict density of stream-living fish. We started by modeling maximum density in relation to body size (length and mass) using quantile regression. We extracted residuals from these models (deviations from maximum predicted density, termed “residual density”). In a second phase of analysis, we applied generalized linear models to predict residual density in relation to habitat factors known to limit abundance of stream-living salmonids (temperature, discharge, and non-native species). Models were based on data from Redband Trout (Oncorhynchus mykiss spp.) sampled over 1615 site visits in the Northern Great Basin Region of southeast Oregon, USA. Results in the first phase of the analysis indicated strong evidence for the influence of body size on maximum fish densities in sampled stream reaches. However, in the second phase of the analysis, we found poor predictive capability for
models attempting to correlate limiting habitat factors to residual density. The importance of body size as a predictor of population density is qualitatively consistent with theoretical expectations based on body size and density dependence in stream-living fish, as well as a host empirical studies reporting inverse relationships between body size and population density. Our inability to predict residual density of Redband Trout in this study is also consistent with a long history of variably successful attempts to predict density based on local environmental variables. Although there are several possible reasons for why density of stream-living is so difficult to predict based on environmental variables, body size is a consistently important factor. Given this, additional work to understand environmental drivers of body size may be a more productive route to better understand factors that ultimately drive population density of stream-living fishes
Antibacterial Activity of Endophytic Actinomycetes Isolated from the Medicinal Plant \u3cem\u3eVochysia divergens\u3c/em\u3e (Pantanal, Brazil)
Endophytic actinomycetes from medicinal plants produce a wide diversity of secondary metabolites (SM). However, to date, the knowledge about endophytes from Brazil remains scarce. Thus, we analyzed the antimicrobial potential of 10 actinomycetes isolated from the medicinal plant Vochysia divergens located in the Pantanal sul-mato-grossense, an unexplored wetland in Brazil. Strains were classified as belonging to the Aeromicrobium, Actinomadura, Microbacterium, Microbispora, Micrococcus, Sphaerisporangium, Streptomyces, and Williamsia genera, through morphological and 16S rRNA phylogenetic analyzes. A susceptibility analysis demonstrated that the strains were largely resistant to the antibiotics oxacillin and nalidixic acid. Additionally, different culture media (SG and R5A), and temperatures (28 and 36°C) were evaluated to select the best culture conditions to produce the active SM. All conditions were analyzed for active metabolites, and the best antibacterial activity was observed from metabolites produced with SG medium at 36°C. The LGMB491 (close related to Aeromicrobium ponti) extract showed the highest activity against methicillin-resistant Staphylococcus aureus (MRSA), with a MIC of 0.04 mg/mL, and it was selected for SM identification. Strain LGMB491 produced 1-acetyl-β-carboline (1), indole-3-carbaldehyde (2), 3-(hydroxyacetyl)-indole (4), brevianamide F (5), and cyclo-(L-Pro-L-Phe) (6) as major compounds with antibacterial activity. In this study, we add to the knowledge about the endophytic community from the medicinal plant V. divergens and report the isolation of rare actinomycetes that produce highly active metabolites
Clinical Applications of Heart Rate Variability in the Triage and Assessment of Traumatically Injured Patients
Heart rate variability (HRV) is a method of physiologic assessment which uses fluctuations in the RR intervals to evaluate modulation of the heart rate by the autonomic nervous system (ANS). Decreased variability has been studied as a marker of increased pathology and a predictor of morbidity and mortality in multiple medical disciplines. HRV is potentially useful in trauma as a tool for prehospital triage, initial patient assessment, and continuous monitoring of critically injured patients. However, several technical limitations and a lack of standardized values have inhibited its clinical implementation in trauma. The purpose of this paper is to describe the three analytical methods (time domain, frequency domain, and entropy) and specific clinical populations that have been evaluated in trauma patients and to identify key issues regarding HRV that must be explored if it is to be widely adopted for the assessment of trauma patients
Epigenome-wide association study for transgenerational disease sperm epimutation biomarkers following ancestral exposure to jet fuel hydrocarbons
Jet fuel hydrocarbons is the generic name for aviation fuels used in gas-turbine engine powered aircraft. The Deepwater Horizon oil rig explosion created the largest environmental disaster in U.S. history, and the second largest oil spill in human history with over 800 million liters of hydrocarbons released into the Gulf of Mexico over a period of 3 months. Due to the widespread use of jet fuel hydrocarbons, this compound mixture has been recognized as the single largest chemical exposure for military personnel. Previous animal studies have demonstrated the ability of jet fuel (JP-8) exposure to promote the epigenetic transgenerational inheritance of disease susceptibility in subsequent generations. The diseases observed include late puberty, kidney, obesity and multiple disease pathologies. The current study is distinct and was designed to identify potential sperm DNA methylation biomarkers for specific transgenerational diseases. Observations show disease specific differential DNA methylation regions (DMRs) called epimutations in the transgenerational F3 generation great-grand-offspring male rats ancestrally exposed to jet fuel. The potential epigenetic DMR biomarkers were identified for late puberty, kidney, obesity, and multiple diseases, and found to be predominantly disease specific. These disease specific DMRs have associated genes that were previously shown to be linked with each of these specific diseases. Therefore, the germline (i.e. sperm) has environmentally induced ancestrally derived epimutations that have the potential to transgenerationally transmit disease susceptibilities to subsequent generations. Epigenetic biomarkers for specific diseases could be developed as medical diagnostics to facilitate clinical management of disease, and allow preventative medicine therapeutics
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