1,004 research outputs found
Dual output variable pitch turbofan actuation system
An improved actuating mechanism was provided for a gas turbine engine incorporating fan blades of the variable pitch variety, the actuator adapted to rotate the individual fan blades within apertures in an associated fan disc. The actuator included means such as a pair of synchronizing ring gears, one on each side of the blade shanks, and adapted to engage pinions disposed thereon. Means were provided to impart rotation to the ring gears in opposite directions to effect rotation of the blade shanks in response to a predetermined input signal. In the event of system failure, a run-away actuator was prevented by an improved braking device which arrests the mechanism
Energy efficient engine ICLS engine bearings, drives and configuration: Detail design report
The detailed design of the forward and aft sumps, the accessory drive system, the lubrication system, and the piping/manifold configuration to be employed in the ICLS engine test of the Energy Efficient Engine is addressed in the report. The design goals for the above components were established based on the requirements of the test cell engine
Haplotype inference based on Hidden Markov Models in the QTL-MAS 2010 multi-generational dataset
<p>Abstract</p> <p>Background</p> <p>We have previously demonstrated an approach for efficient computation of genotype probabilities, and more generally probabilities of allele inheritance in inbred as well as outbred populations. That work also included an extension for haplotype inference, or phasing, using Hidden Markov Models. Computational phasing of multi-thousand marker datasets has not become common as of yet. In this communication, we further investigate the method presented earlier for such problems, in a multi-generational dataset simulated for QTL detection.</p> <p>Results</p> <p>When analyzing the dataset simulated for the 14th QTLMAS workshop, the phasing produced showed zero deviations compared to original simulated phase in the founder generation. In total, 99.93% of all markers were correctly phased. 97.68% of the individuals were correct in all markers over all 5 simulated chromosomes. Results were produced over a weekend on a small computational cluster. The specific algorithmic adaptations needed for the Markov model training approach in order to reach convergence are described.</p> <p>Conclusions</p> <p>Our method provides efficient, near-perfect haplotype inference allowing the determination of completely phased genomes in dense pedigrees. These developments are of special value for applications where marker alleles are not corresponding directly to QTL alleles, thus necessitating tracking of allele origin, and in complex multi-generational crosses. The cnF2freq codebase, which is in a current state of active development, is available under a BSD-style license.</p
Energy efficient engine: Flight propulsion system preliminary analysis and design
The characteristics of an advanced flight propulsion system (FPS), suitable for introduction in the late 1980's to early 1990's, was more fully defined. It was determined that all goals for efficiency, environmental considerations, and economics could be met or exceeded with the possible exception of NOx emission. In evaluating the FPS, all aspects were considered including component design, performance, weight, initial cost, maintenance cost, engine system integration (including nacelle), and aircraft integration considerations. The current FPS installed specific fuel consumption was reduced 14.2% from that of the CF6-50C reference engine. When integrated into an advanced, subsonic, study transport, the FPS produced a fuel burn savings of 15 to 23% and a direct operating cost reduction of 5 to 12% depending on the mission and study aircraft characteristics relative to the reference engine
The consequences of perceived age discrimination amongst older police officers : is social support a buffer ?
This paper considers the possible psychological consequences of perceived agediscrimination, and the possible buffering effect of social support. Findings, based on a studyof perceived age discrimination amongst police officers in the North of England, suggest thatage discrimination acts as a stressor, with officers experiencing negative effects of perceivedage discrimination on job and life satisfaction, perceived power and prestige of the job, andaffective and normative commitment, along with positive effects on withdrawal cognitionsand continuance commitment. For work-based social support, there were positive maineffects on job and satisfaction, power and prestige of the job, and affective and normativecommitment, and a negative main effect on withdrawal cognitions. However, there were nosignificant moderating effects for work-based social support, and we found the anticipatedbuffering effect for non-work-based social support only for life satisfaction, with reversebuffering for job satisfaction and normative commitment. The limitations and implications ofthe study are discussed
Ethnic and gender differences in help seeking for substance disorders among Black Americans
This paper uses the National Survey of American Life (NSAL) to examine within group differences regarding help-seeking for substance disorders among a US sample of African American and Caribbean Black men and women. We examined ethnic and gender differences in the type of providers sought for substance disorder treatment, as well as reasons for avoiding treatment. Results indicate that overall, few ethnic differences exist; however, African Americans are more likely than Caribbean Blacks to seek help from human service professionals (including a religious or spiritual advisor) and from informal sources of treatment such as self-help groups. Black men with a substance disorder were more likely to see a psychiatrist than Black women. Findings regarding reasons for avoiding treatment suggest that there may be a need to provide better education about the utility of substance disorder treatment, even before problems reach a high level of severity.The National Institute on Drug Abuse training grant #T32DA007267The National Institute of Mental Health training grant #T32 MH16806-25.The NSAL is supported by the National Institute of Mental Health (grant U01-MH57716) with supplemental support from the Office of Behavioral and Social Science Research at the National Institutes of Health and the University of Michigan.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/164713/1/Redmond2017_Article_EthnicAndGenderDifferencesInHe.pdfDescription of Redmond2017_Article_EthnicAndGenderDifferencesInHe.pdf : Main articl
Pressure and Flow Properties of Cannulae for Extracorporeal Membrane Oxygenation II: Drainage (Venous) Cannulae
The use of extracorporeal life support devices such as extracorporeal membrane oxygenation in adults requires cannulation of the patient's vessels with comparatively large diameter cannulae to allow circulation of large volumes of blood (>5 L/min). The cannula diameter and length are the major determinants for extracorporeal membrane oxygenation flow. Manufacturing companies present pressure-flow charts for the cannulae; however, these tests are performed with water. Aims of this study were 1. to investigate the specified pressure-flow charts obtained when using human blood as the circulating medium and 2. to support extracorporeal membrane oxygenation providers with pressure-flow data for correct choice of the cannula to reach an optimal flow with optimal hydrodynamic performance. Eighteen extracorporeal membrane oxygenation drainage cannulae, donated by the manufacturers (n = 6), were studied in a centrifugal pump driven mock loop. Pressure-flow properties and cannula features were described. The results showed that when blood with a hematocrit of 27% was used, the drainage pressure was consistently higher for a given flow (range 10%-350%) than when water was used (data from each respective manufacturer's product information). It is concluded that the information provided by manufacturers in line with regulatory guidelines does not correspond to clinical performance and therefore may not provide the best guidance for clinicians.info:eu-repo/semantics/publishedVersio
The point of maximum curvature as a marker for physiological time series
We present a geometric analysis of the model of Stirling. In particular we analyze the curvature of a heart rate time series in response to a step like increment in the exercise intensity. We present solutions for the point of maximum curvature which can be used as a marker of physiological interest. This marker defines the point after which the heart rate no longer continues to rapidly rise and instead follows either a steady state or slow rise. These methods are then applied to find analytic solutions for a mono exponential model which is commonly used in the literature to model the response to a moderate exercise intensity. Numerical solutions are then found for the full model and parameter values presented in Stirling
Mapping genetic determinants of host susceptibility to Pseudomonas aeruginosa lung infection in mice.
Background: P. aeruginosa is one of the top three causes of opportunistic human bacterial infections. The remarkable
variability in the clinical outcomes of this infection is thought to be associated with genetic predisposition. However,
the genes underlying host susceptibility to P. aeruginosa infection are still largely unknown.
Results: As a step towards mapping these genes, we applied a genome wide linkage analysis approach to a mouse
model. A large F2 intercross population, obtained by mating P. aeruginosa-resistant C3H/HeOuJ, and susceptible A/J
mice, was used for quantitative trait locus (QTL) mapping. The F2 progenies were challenged with a P. aeruginosa
clinical strain and monitored for the survival time up to 7 days post-infection, as a disease phenotype associated trait.
Selected phenotypic extremes of the F2 distribution were genotyped with high-density single nucleotide polymorphic
(SNP) markers, and subsequently QTL analysis was performed. A significant locus was mapped on chromosome 6 and
was named P. aeruginosa infection resistance locus 1 (Pairl1). The most promising candidate genes, including Dok1,
Tacr1, Cd207, Clec4f, Gp9, Gata2, Foxp1, are related to pathogen sensing, neutrophils and macrophages recruitment and
inflammatory processes.
Conclusions: We propose a set of genes involved in the pathogenesis of P. aeruginosa infection that may be explored
to complement human studie
Acute sleep deprivation increases portion size and affects food choice in young men
SummaryAcute sleep loss increases food intake in adults. However, little is known about the influence of acute sleep loss on portion size choice, and whether this depends on both hunger state and the type of food (snack or meal item) offered to an individual. The aim of the current study was to compare portion size choice after a night of sleep and a period of nocturnal wakefulness (a condition experienced by night-shift workers, e.g. physicians and nurses). Sixteen men (age: 23±0.9 years, BMI: 23.6±0.6kg/m2) participated in a randomized within-subject design with two conditions, 8-h of sleep and total sleep deprivation (TSD). In the morning following sleep interventions, portion size, comprising meal and snack items, was measured using a computer-based task, in both fasted and sated state. In addition, hunger as well as plasma levels of ghrelin were measured. In the morning after TSD, subjects had increased plasma ghrelin levels (13%, p=0.04), and chose larger portions (14%, p=0.02), irrespective of the type of food, as compared to the sleep condition. Self-reported hunger was also enhanced (p<0.01). Following breakfast, sleep-deprived subjects chose larger portions of snacks (16%, p=0.02), whereas the selection of meal items did not differ between the sleep interventions (6%, p=0.13). Our results suggest that overeating in the morning after sleep loss is driven by both homeostatic and hedonic factors. Further, they show that portion size choice after sleep loss depend on both an individual's hunger status, and the type of food offered
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