2,155 research outputs found
Analysis, design, fabrication and testing of an optical tip clearance sensor
Analyses and the design, fabrication, and testing of an optical tip clearance sensor with intended application in aircraft propulsion control systems are reported. The design of a sensor test rig, evaluation of optical sensor components at elevated temperatures, sensor design principles, sensor test results at room temperature, and estimations of sensor accuracy at temperatures of an aircraft engine environment are discussed. Room temperature testing indicated possible measurement accuracies of less than 12.7 microns (0.5 mils). Ways to improve performance at engine operating temperatures are recommended. The potential of this tip clearance sensor is assessed
Electromagnetic interferences from plasmas generated in meteoroids impacts
It is shown that the plasma, generated during an impact of a meteoroid with
an artificial satellite, can produce electromagnetic radiation below the
microwave frequency range. This interference is shown to exceed local noise
sources and might disturb regular satellite operations.Comment: 6 pages, no figures. This version macthes the published versio
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Functionally Annotating Regulatory Elements in the Equine Genome Using Histone Mark ChIP-Seq.
One of the primary aims of the Functional Annotation of ANimal Genomes (FAANG) initiative is to characterize tissue-specific regulation within animal genomes. To this end, we used chromatin immunoprecipitation followed by sequencing (ChIP-Seq) to map four histone modifications (H3K4me1, H3K4me3, H3K27ac, and H3K27me3) in eight prioritized tissues collected as part of the FAANG equine biobank from two thoroughbred mares. Data were generated according to optimized experimental parameters developed during quality control testing. To ensure that we obtained sufficient ChIP and successful peak-calling, data and peak-calls were assessed using six quality metrics, replicate comparisons, and site-specific evaluations. Tissue specificity was explored by identifying binding motifs within unique active regions, and motifs were further characterized by gene ontology (GO) and protein-protein interaction analyses. The histone marks identified in this study represent some of the first resources for tissue-specific regulation within the equine genome. As such, these publicly available annotation data can be used to advance equine studies investigating health, performance, reproduction, and other traits of economic interest in the horse
Determinants of neonatal mortality in Indonesia
<p>Abstract</p> <p>Background</p> <p>Neonatal mortality accounts for almost 40 per cent of under-five child mortality, globally. An understanding of the factors related to neonatal mortality is important to guide the development of focused and evidence-based health interventions to prevent neonatal deaths. This study aimed to identify the determinants of neonatal mortality in Indonesia, for a nationally representative sample of births from 1997 to 2002.</p> <p>Methods</p> <p>The data source for the analysis was the 2002–2003 Indonesia Demographic and Health Survey from which survival information of 15,952 singleton live-born infants born between 1997 and 2002 was examined. Multilevel logistic regression using a hierarchical approach was performed to analyze the factors associated with neonatal deaths, using community, socio-economic status and proximate determinants.</p> <p>Results</p> <p>At the community level, the odds of neonatal death was significantly higher for infants from East Java (OR = 5.01, p = 0.00), and for North, Central and Southeast Sulawesi and Gorontalo combined (OR = 3.17, p = 0.03) compared to the lowest neonatal mortality regions of Bali, South Sulawesi and Jambi provinces. A progressive reduction in the odds was found as the percentage of deliveries assisted by trained delivery attendants in the cluster increased. The odds of neonatal death were higher for infants born to both mother and father who were employed (OR = 1.84, p = 0.00) and for infants born to father who were unemployed (OR = 2.99, p = 0.02). The odds were also higher for higher rank infants with a short birth interval (OR = 2.82, p = 0.00), male infants (OR = 1.49, p = 0.01), smaller than average-sized infants (OR = 2.80, p = 0.00), and infant's whose mother had a history of delivery complications (OR = 1.81, p = 0.00). Infants receiving any postnatal care were significantly protected from neonatal death (OR = 0.63, p = 0.03).</p> <p>Conclusion</p> <p>Public health interventions directed at reducing neonatal death should address community, household and individual level factors which significantly influence neonatal mortality in Indonesia. Low birth weight and short birth interval infants as well as perinatal health services factors, such as the availability of skilled birth attendance and postnatal care utilization should be taken into account when planning the interventions to reduce neonatal mortality in Indonesia.</p
Perceptions Of School By Two Teenage Boys With Asperger Syndrome And Their Mothers: A Qualitative Study
This qualitative study aimed to develop an understanding of the challenges faced by teenage boys with Asperger syndrome and their mothers. A case study approach was used to collect data from two 13-year-old boys who have Asperger syndrome and their mothers in Queensland, Australia. Data were collected through the use of semi¬structured interviews. The words of the boys and their mothers provide a valuable insight into the personal experiences and feelings of the par¬ticipants. An inductive approach to data analysis identified four themes: (1) developmental differences; (2) problems associated with the general characteristics of Asperger syndrome (i.e. communication and social difficulties, restricted range of interests, a need for routine); (3) stress; and (4) 'masquerading'. The first three themes relate strongly to the current literature, but the emergence of masquerading is of particular interest in developing a fuller understanding of the experiences of individuals with Asperger syndrome at school
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Sex Hormone-Binding Globulin Levels Are Inversely Associated With Nonalcoholic Fatty Liver Disease in HIV-Infected and -Uninfected Men.
BackgroundNonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease worldwide. Elevated sex hormone-binding globulin (SHBG) levels have been observed in the setting of HIV and may protect against some metabolic disorders. We aimed to investigate whether higher SHBG levels may protect against NAFLD in men with/without HIV.MethodsNAFLD was assessed using noncontrast computed tomography in 530 men in the Multicenter AIDS Cohort Study (MACS) who drank <3 alcoholic drinks/d and were uninfected with chronic hepatitis C or B (340HIV+, 190HIV-). Morning serum samples were tested for SHBG, total testosterone (TT), and adiponectin. Multivariable logistic regression was used to assess associations between HIV, SHBG, TT, adiponectin, and NAFLD.ResultsMedian SHBG was highest among HIV+/NAFLD- men and lowest among HIV-/NAFLD+ men. Adjusted for demographics, HIV, visceral adiposity, HOMA-IR, TT, and PNPLA3 genotype, higher SHBG was associated with lower odds of NAFLD (odds ratio [OR], 0.52 per doubling; 95% confidence interval [CI], 0.34-0.80). In separate multivariable models without SHBG, HIV (OR, 0.46; 95% CI, 0.26-0.79) and higher adiponectin (OR, 0.66 per doubling; 95% CI, 0.49-0.89) were associated with lower NAFLD odds, whereas TT was not significantly associated (OR, 0.74 per doubling; 95% CI, 0.53-1.04). Adjusting for SHBG attenuated the associations of HIV (OR, 0.61; 95% CI, 0.34-1.08) and adiponectin (OR, 0.74; 95% CI, 0.54-1.02) with NAFLD.ConclusionsSHBG levels were higher among HIV+ men, were independently associated with lower NAFLD, and could partially explain the associations of HIV and higher adiponectin with lower NAFLD in our cohort. These findings suggest that SHBG may protect against NAFLD, supporting further prospective and mechanistic studies
Physiological and Perceived Effects of Forearm or Head Cooling During Simulated Firefighting Activity and Rehabilitation.
CONTEXT:  Cooling devices aim to protect firefighters by attenuating a rise in body temperature. Devices for head cooling (HC) while firefighting and forearm cooling (FC) during rehabilitation (RHB) intervals are commonly marketed, but research regarding their efficacy is limited.
OBJECTIVE:  To investigate the physiological and perceived effects of HC and FC during firefighting drills and RHB.
DESIGN:  Randomized controlled clinical trial.
SETTING:  Firefighter training center.
PATIENTS OR OTHER PARTICIPANTS:  Twenty-seven male career firefighters (age = 39 ± 7 years; height = 169 ± 7 cm; weight = 95.4 ± 16.8 kg).
INTERVENTION(S):  Firefighters were randomly assigned to 1 condition: HC (n = 9), in which participants completed drills wearing a cold gel pack inside their helmet; FC (n = 8), in which participants sat on a collapsible chair with water-immersion arm troughs during RHB; or control (n = 10), in which participants used no cooling devices. Firefighters completed four 15-minute drills (D1-D4) wearing full bunker gear and breathing apparatus. Participants had a 15-min RHB after D2 (RHB1) and D4 (RHB2).
MAIN OUTCOME MEASURE(S):  Change (Δ) in gastrointestinal temperature (T
RESULTS:  The T
CONCLUSIONS:  The HC did not attenuate rises in physiological or perceptual variables during firefighting drills. The FC effectively reduced
A tale of two cities: The impact of airline mergers and consolidation at London and New York
This paper considers the changes to airline networks, service patterns, and competition that have taken place as a result of recent airline mergers on both sides of the North Atlantic as well as through transatlantic alliances. Capacity, frequency and the competitive position are studied at London and New York with the use of schedule data within different markets in which measures of market concentration are evaluated. International Civil Aviation Organization data is employed to examine load factors on international routes, and UK Civil Aviation Authority data to consider the distribution of traffic between airports in London. It is shown that the effectiveness of the hubs has increased, with enhanced efficiency for surviving airlines, through fewer competitors, an enlarged network and greater control of capacity. Potential concerns are identified however, regarding passenger choice,pricing, and service options that suggest the industry is moving toward an oligopoly. Smaller cities are also seen to be the losers from consolidation with slot divestments favoring increased service in the dense markets, with many regional links being axed altogether. The paper supplements the literature on airline consolidation, with a particular focus on the two biggest markets in the world—London and New York—which demonstrate some similar but also some different issues. Both airline network impacts and choice, and service for local consumers are considered
Nonet Symmetry and Two-Body Decays of Charmed Mesons
The decay of charmed mesons into pseudoscalar (P) and vector (V) mesons is
studied in the context of nonet symmetry. We have found that it is badly broken
in the PP channels and in the P sector of the PV channels as expected from the
non-ideal mixing of the \eta and the \eta'. In the VV channels, it is also
found that nonet symmetry does not describe the data well. We have found that
this discrepancy cannot be attributed entirely to SU(3) breaking at the usual
level of 20--30%. At least one, or both, of nonet and SU(3) symmetry must be
very badly broken. The possibility of resolving the problem in the future is
also discussed.Comment: 9 pages, UTAPHY-HEP-
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