72,154 research outputs found

    Evaluation of dry lubricants and bearings for spacecraft applications

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    Performance of dry film lubricated ball bearings in high vacuum environmen

    COW-CALF PRODUCERS' PERCEIVED PROFIT MAXIMIZATION OBJECTIVE: A LOGIT ANALYSIS

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    A logistic regression (logit) model was developed to examine how socioeconomic characteristics of cow-calf producers influenced their perceptions of themselves as profit maximizers. Amount of pasture acreage, percent of income earned from the cow-calf operation, and desire to increase net worth and efficiently use labor significantly increased the producer's probability of claiming to be in the business primarily to maximize profits. Some sociological reasons for owning cattle significantly reduced the probability of the producer claiming to be a profit maximizer while others significantly increased the probability.Livestock Production/Industries,

    Maternal methadone use in pregnancy : factors associated with the development of neonatal abstinence syndrome and implications for healthcare resources

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    The objectives of this study were to investigate factors associated with the development of neonatal abstinence syndrome (NAS) and to assess the implications for healthcare resources of infants born to drug-misusing women. Design. Retrospective cohort study from 1 January 2004 to 31 December 2006. Setting. Inner-city maternity hospital providing dedicated multidisciplinary care to drug-misusing women. Four hundred and fifty singleton pregnancies of drugmisusing women prescribed substitute methadone in pregnancy. Development of NAS and duration of infant hospital stay. 45.5% of infants developed NAS requiring pharmacological treatment. The odds ratio of the infant developing NAS was independently related to prescribed maternal methadone dose rather than associated polydrug misuse. Breastfeeding was associated with reduced odds of requiring treatment for NAS (OR 0.55, 95% CI 0.34-0.88). Preterm birth did not influence the odds of the infant receiving treatment for NAS. 48.4% infants were admitted to the neonatal unit (NNU) 40% of these primarily for treatment of NAS. The median total hospital stay for all infants was 10 days (interquartile range 7-17 days). Infants born to methadone-prescribed drug-misusing mothers represented 2.9% of hospital births, but used 18.2% of NNU cot days. Higher maternal methadone dose is associated with a higher incidence of NAS. Pregnant drug-misusing women should be encouraged and supported to breastfeed. Their infants are extremely vulnerable and draw heavily on healthcare resources

    A control system formulation of the mechanism that controls the secretions of serum group hormone in humans during sleep

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    Plasma growth hormone concentrations during sleep were determined experimentally. An elevated level of plasma growth hormone was observed during the initial phase of sleep and remained elevated for approximately 3 hr before returning to the steady-state level. Moreover, subsequent to a prolonged interruption of sleep, of the order of 2-3 hr, an elevated level of plasma growth hormone was again observed during the initial phase of resumed sleep. A control system formulation of the mechanism that controls the secretions of serum growth hormone in humans was used to account for the growth hormone responses observed

    Mapping Functions in Health-Related Quality of Life: Mapping From Two Cancer-Specific Health-Related Quality-of-Life Instruments to EQ-5D-3L.

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    BACKGROUND: Clinical trials in cancer frequently include cancer-specific measures of health but not preference-based measures such as the EQ-5D that are suitable for economic evaluation. Mapping functions have been developed to predict EQ-5D values from these measures, but there is considerable uncertainty about the most appropriate model to use, and many existing models are poor at predicting EQ-5D values. This study aims to investigate a range of potential models to develop mapping functions from 2 widely used cancer-specific measures (FACT-G and EORTC-QLQ-C30) and to identify the best model. METHODS: Mapping models are fitted to predict EQ-5D-3L values using ordinary least squares (OLS), tobit, 2-part models, splining, and to EQ-5D item-level responses using response mapping from the FACT-G and QLQ-C30. A variety of model specifications are estimated. Model performance and predictive ability are compared. Analysis is based on 530 patients with various cancers for the FACT-G and 771 patients with multiple myeloma, breast cancer, and lung cancer for the QLQ-C30. RESULTS: For FACT-G, OLS models most accurately predict mean EQ-5D values with the best predicting model using FACT-G items with similar results using tobit. Response mapping has low predictive ability. In contrast, for the QLQ-C30, response mapping has the most accurate predictions using QLQ-C30 dimensions. The QLQ-C30 has better predicted EQ-5D values across the range of possible values; however, few respondents in the FACT-G data set have low EQ-5D values, which reduces the accuracy at the severe end. CONCLUSIONS: OLS and tobit mapping functions perform well for both instruments. Response mapping gives the best model predictions for QLQ-C30. The generalizability of the FACT-G mapping function is limited to populations in moderate to good health

    Discrimination of the light CP-odd scalars between in the NMSSM and in the SLHM

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    The presence of the light CP-odd scalar boson predicted in the next-to-minimal supersymmetric model (NMSSM) and the simplest little Higgs model (SLHM) dramatically changes the phenomenology of the Higgs sector. We suggest a practical strategy to discriminate the underlying model of the CP-odd scalar boson produced in the decay of the standard model-like Higgs boson. We define the decay rate of "the non bb-tagged jet pair" with which we compute the ratio of decay rates into lepton and jets. They show much different behaviors between the NMSSM and the SLHM.Comment: 5 pages, 2 figures (5 figure files

    Coherent optical implementations of the fast Fourier transform and their comparison to the optical implementation of the quantum Fourier transform

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    Optical structures to implement the discrete Fourier transform (DFT) and fast Fourier transform (FFT) algorithms for discretely sampled data sets are considered. In particular, the decomposition of the FFT algorithm into the basic Butterfly operations is described, as this allows the algorithm to be fully implemented by the successive coherent addition and subtraction of two wavefronts (the subtraction being performed after one has been appropriately phase shifted), so facilitating a simple and robust hardware implementation based on waveguided hybrid devices as employed in coherent optical detection modules. Further, a comparison is made to the optical structures proposed for the optical implementation of the quantum Fourier transform and they are shown to be very similar
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