3,640 research outputs found
Fuel injection assembly for gas turbine engine combustor
A fuel injection assembly for a gas turbine engine combustor, including at least one fuel stem, a plurality of concentrically disposed tubes positioned within each fuel stem, wherein a cooling supply flow passage, a cooling return flow passage, and a tip fuel flow passage are defined thereby, and at least one fuel tip assembly connected to each fuel stem so as to be in flow communication with the flow passages, wherein an active cooling circuit for each fuel stem and fuel tip assembly is maintained by providing all active fuel through the cooling supply flow passage and the cooling return flow passage during each stage of combustor operation. The fuel flowing through the active cooling circuit is then collected so that a predetermined portion thereof is provided to the tip fuel flow passage for injection by the fuel tip assembly
Risk factors for developing clinical infection with methicillin-resistant Staphylococcus aureus (MRSA) amongst hospital patients initially only colonized with MRSA.
In hospital outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) many patients are initially colonized without infection. The reasons why some progress to infection while others do not are not known. A cohort of 479 hospital patients, initially only colonized with MRSA, was followed prospectively for the development of MRSA infection. Risk factors for progression to infection were assessed using Cox proportional hazards survival analysis. Fifty-three patients (11.1%) developed 68 MRSA infections. Intensive care setting, administration of three or more antibiotics, ulcers, surgical wounds, nasogastric or endotracheal tubes, drains, and urinary or intravenous catheterization were all associated with increased rates of MRSA infection. Multivariate analysis showed that intensive care patients, compared with medical patients, had a higher rate of developing MRSA infection within the first four days of admission, with a hazard ratio of 26.9 (95% CI 5.7-126). Surgical wounds, pressure ulcers and intravenous catheterization were also independent risk factors, with hazard ratios (and 95% CI) of 2.9 (1.3-6.3); 3.0 (1.6-5.7) and 4.7 (1.4-15.6), respectively. These findings suggest that, during an MRSA outbreak, clinical infection would be reduced if surgical and intensive care patients received priority for the prevention of initial colonization with MRSA. Prevention of pressure ulcers, and strict aseptic care of intravenous catheters and surgical wounds would also reduce the development of MRSA infection. Since early treatment with vancomycin is known to reduce the mortality, patients colonized with MRSA who also have one or more of these risk factors may warrant empirical vancomycin therapy at the earliest suggestion of infection
Patterns of Fetal Heart Rate Response at ā¼30 Weeks Gestation Predict Size at Birth
There is evidence that fetal exposure to maternal stress is associated with adverse birth outcomes. Less is known about the association between fetal responses to a stressor and indicators of fetal maturity and developmental outcomes. The purpose of the present study was to determine whether fetal heart rate (FHR) patterns in response to a startling stimulus at ā¼30 weeks of gestation were associated with gestational age at birth and birth weight. FHR was measured in 156 maternalāfetal dyads following a vibroacoustic stimulus. All pregnancies were singleton intrauterine pregnancies in English-speaking women who were primarily married, middle class, White and at least 18 years of age. Group-based trajectory modeling identified five groups of fetuses displaying distinctive longitudinal trajectories of FHR response to the startling stimulus. The FHR group trajectories were significantly associated with birth weight percentile (P \u3c 0.01) even after controlling for estimated fetal weight at the time of assessment and parity, which are the known factors influencing birth weight (P \u3c 0.01). Post hoc analyses indicated that two groups accounted for the association between FHR patterns and birth weight. The group (n = 23) with the lowest birth weight exhibited an immediate FHR deceleration followed by an immediate acceleration that does not recover. An FHR pattern characterized by immediate and fast acceleration to the peak and a slow discovery to baseline was associated with the highest birth weight. This is the first direct evidence showing that low birth weight and the resulting neurological consequences may have their origins in early fetal development
Prescription of the first prosthesis and later use in children with congenital unilateral upper limb deficiency: A systematic review
Background: The prosthetic rejection rates in children with an upper limb transversal reduction deficiency are considerable. It is unclear whether the timing of the first prescription of the prosthesis contributes to the rejection rates. Objective: To reveal whether scientific evidence is available in literature to confirm the hypothesis that the first prosthesis of children with an upper limb deficiency should be prescribed before two years of age. We expect lower rejection rates and better functional outcomes in children fitted at young age. Methods: A computerized search was performed in several databases (Medline, Embase, Cinahl, Amed, Psycinfo, PiCarta and the Cochrane database). A combination of the following keywords and their synonyms was used: "prostheses, upper limb, upper extremity, arm and congenital''. Furthermore, references of conference reports, references of most relevant studies, citations of most relevant studies and related articles were checked for relevancy. Results: The search yielded 285 publications, of which four studies met the selection criteria. The methodological quality of the studies was low. All studies showed a trend of lower rejection rates in children who were provided with their first prosthesis at less than two years of age. The pooled odds ratio of two studies showed a higher rejection rate in children who were fitted over two years of age ( pooled OR 3.6, 95% CI 1.6-8.0). No scientific evidence was found concerning the relation between the age at which a prosthesis was prescribed for the first time and functional outcomes. Conclusion: In literature only little evidence was found for a relationship between the fitting of a first prosthesis in children with a congenital upper limb deficiency and rejection rates or functional outcomes. As such, clinical practice of the introduction of a prosthesis is guided by clinical experience rather than by evidence-based medicine
From kitchen to classroom: Assessing the impact of cleaner burning biomass-fuelled cookstoves on primary school attendance in Karonga district, northern Malawi
Household air pollution from burning solid fuels is responsible for an estimated 2.9 million premature deaths worldwide each year and 4.5% of global disability-adjusted life years, while cooking and fuel collection pose a considerable time burden, particularly for women and children. Cleaner burning biomass-fuelled cookstoves have the potential to lower exposure to household air pollution as well as reduce fuelwood demand by increasing the combustion efficiency of cooking fires, which may in turn yield ancillary benefits in other domains. The present paper capitalises on opportunities offered by the Cooking and Pneumonia Study (CAPS), the largest randomised trial of biomass-fuelled cookstoves on health outcomes conducted to date, the design of which allows for the evaluation of additional outcomes at scale. This mixed methods study assesses the impact of cookstoves on primary school absenteeism in Karonga district, northern Malawi, in particular by conferring health and time and resource gains on young people aged 5ā18. The analysis combines quantitative data from 6168 primary school students with in-depth interviews and focus group discussions carried out among 48 students in the same catchment area in 2016. Negative binomial regression models find no evidence that the cookstoves affected primary school absenteeism overall [IRR 0.92 (0.71ā1.18), p = 0.51]. Qualitative analysis suggests that the cookstoves did not sufficiently improve household health to influence school attendance, while the time and resource burdens associated with cooking activitiesāalthough reduced in intervention householdsāwere considered to be compatible with school attendance in both trial arms. More research is needed to assess whether the cookstoves influenced educational outcomes not captured by the attendance measure available, such as timely arrival to school or hours spent on homework
Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific
Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern GalƔpagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification
Microwave System for Detecting Ice on Aircraft
A microwave-based system has been developed as a means of detecting ice on aircraft surfaces, with enough sensitivity to provide a warning before the ice accretes to a dangerous thickness. The system can measure the thickness of ice from a few mils (1 mil = 0.0254 mm) to about 1/4 in. (.6 mm) and can distinguish among (1) ice, (2) water (or deicing fluid), and (3) a mixture of ice and water (or deicing fluid). Sensors have been ruggedized to withstand the rain erosion environment
The Nature of Boulder-Rich Deposits in the Upper Big Flat Brook Drainage, Sussex County, New Jersey
The upper reaches of the Big Flat Brook drainage, northwest of Kittatinny Mountain, contain a variety of glacial, pro-glacial, and periglacial deposits from the Late Quaternary. The area is dominated by recessional moraines and ubiquitous ground moraine, along with meltwater deposits, drumlins, and possible postglacial periglacial features. We have identified a curious boulder-rich deposit in the vicinity of Lake Ocquittunk and Lake Wapalanne on upper Big Flat Brook. The area where these boulder deposits occur is mapped (1:24,000 surficial geology) as till. As mapped and observed, larger cobbles and boulders within the till are quartz-pebble conglomerate, quartzite, sandstone, and shale. The boulder-rich deposits differ from the typical till, however. Unlike the local till, which is more mixed in lithology, the boulder deposits are nearly exclusively Shawangunk conglomerate. The deposits are discontinuous, but appear to occur at a topographic level above the meltwater stream terraces. The boulders in the deposits lie partially embedded in soil, but are very closely spaced. The boulders range in size from ~20cm to over 100cm, and present a subrounded to subangular shape. There appears to be a fabric orientation of the boulders, NE-SW, with subsidiary orientations. As the boulder deposits differ from other mapped features in the area, we attempt to ascertain the origin for the deposits. Unique moraine dynamics, meltwater flood, periglacial slope movement, and slope-snow bank processes are possible explanations. Detailed examination of these boulder deposits will provide a finer explanation of the glacial and post-glacial geomorphic history of the area
Earlier menarche is associated with a higher prevalence of Herpes simplex type-2 (HSV-2) in young women in rural Malawi.
Remarkably little is known about associations between age at menarche and sexually transmitted infections, although girls with earlier menarche tend to have earlier sexual debut and school drop-out, so an association might be expected. In a population-based survey of >3000 women aged 15-30 in northern Malawi we show that those with earlier menarche had earlier sexual debut, earlier marriage and were more often Herpes simplex type-2 (HSV-2) positive. Compared to those with menarche aged <14, the age-adjusted odds ratios for HSV-2 were 0.89 (95%CI 0.71-1.1), 0.71 (0.57-0.89) and 0.69 (0.54-0.89) for menarche aged 14, 15 and 16+ respectively. This association persisted after adjusting for socio-economic factors, including schooling, and for sexual behaviour. No such association was seen with HIV infection, which is much less common and less uniformly distributed than HSV-2 in this population. The extra vulnerability of girls with earlier menarche needs to be recognised. DOI: http://dx.doi.org/10.7554/eLife.01604.001
Earlier menarche is associated with a higher prevalence of Herpes simplex type-2 (HSV-2) in young women in rural Malawi
Remarkably little is known about associations between age at menarche and sexually transmitted infections, although girls with earlier menarche tend to have earlier sexual debut and school drop-out, so an association might be expected. In a population-based survey of >3000 women aged 15ā30 in northern Malawi we show that those with earlier menarche had earlier sexual debut, earlier marriage and were more often Herpes simplex type-2 (HSV-2) positive. Compared to those with menarche aged <14, the age-adjusted odds ratios for HSV-2 were 0.89 (95%CI 0.71ā1.1), 0.71 (0.57ā0.89) and 0.69 (0.54ā0.89) for menarche aged 14, 15 and 16+ respectively. This association persisted after adjusting for socio-economic factors, including schooling, and for sexual behaviour. No such association was seen with HIV infection, which is much less common and less uniformly distributed than HSV-2 in this population. The extra vulnerability of girls with earlier menarche needs to be recognised
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