23,255 research outputs found

    Breast feeding and resilience against psychosocial stress

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    BACKGROUND: Some early life exposures may result in a well controlled stress response, which can reduce stress related anxiety. Breast feeding may be a marker of some relevant exposures. AIMS: To assess whether breast feeding is associated with modification of the relation between parental divorce and anxiety. METHODS: Observational study using longitudinal birth cohort data. Linear regression was used to assess whether breast feeding modifies the association of parental divorce/separation with anxiety using stratification and interaction testing. Data were obtained from the 1970 British Cohort Study, which is following the lives of those born in one week in 1970 and living in Great Britain. This study uses information collected at birth and at ages 5 and 10 years for 8958 subjects. Class teachers answered a question on anxiety among 10 year olds using an analogue scale (range 0ā€“50) that was log transformed to minimise skewness. RESULTS: Among 5672 nonā€breast fed subjects, parental divorce/separation was associated with a statistically significantly raised risk of anxiety, with a regression coefficient (95% CI) of 9.4 (6.1 to 12.8). Among the breast fed group this association was much lower: 2.2 (āˆ’2.6 to 7.0). Interaction testing confirmed statistically significant effect modification by breast feeding, independent of simultaneous adjustment for multiple potential confounding factors, producing an interaction coefficient of āˆ’7.0 (āˆ’12.8 to āˆ’1.2), indicating a 7% reduction in anxiety after adjustment. CONCLUSIONS: Breast feeding is associated with resilience against the psychosocial stress linked with parental divorce/separation. This could be because breast feeding is a marker of exposures related to maternal characteristics and parentā€“child interaction

    Using Ancient Samples in Projection Analysis.

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    Projection analysis is a tool that extracts information from the joint allele frequency spectrum to better understand the relationship between two populations. In projection analysis, a test genome is compared to a set of genomes from a reference population. The projection's shape depends on the historical relationship of the test genome's population to the reference population. Here, we explore in greater depth the effects on the projection when ancient samples are included in the analysis. First, we conduct a series of simulations in which the ancient sample is directly ancestral to a present-day population (one-population model), or the ancient sample is ancestral to a sister population that diverged before the time of sampling (two-population model). We find that there are characteristic differences between the projections for the one-population and two-population models, which indicate that the projection can be used to determine whether a test genome is directly ancestral to a present-day population or not. Second, we compute projections for several published ancient genomes. We compare two Neanderthals and three ancient human genomes to European, Han Chinese and Yoruba reference panels. We use a previously constructed demographic model and insert these five ancient genomes to assess how well the observed projections are recovered

    Feedback Control of Traveling Wave Solutions of the Complex Ginzburg Landau Equation

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    Through a linear stability analysis, we investigate the effectiveness of a noninvasive feedback control scheme aimed at stabilizing traveling wave solutions of the one-dimensional complex Ginzburg Landau equation (CGLE) in the Benjamin-Feir unstable regime. The feedback control is a generalization of the time-delay method of Pyragas, which was proposed by Lu, Yu and Harrison in the setting of nonlinear optics. It involves both spatial shifts, by the wavelength of the targeted traveling wave, and a time delay that coincides with the temporal period of the traveling wave. We derive a single necessary and sufficient stability criterion which determines whether a traveling wave is stable to all perturbation wavenumbers. This criterion has the benefit that it determines an optimal value for the time-delay feedback parameter. For various coefficients in the CGLE we use this algebraic stability criterion to numerically determine stable regions in the (K,rho) parameter plane, where rho is the feedback parameter associated with the spatial translation and K is the wavenumber of the traveling wave. We find that the combination of the two feedbacks greatly enlarges the parameter regime where stabilization is possible, and that the stability regions take the form of stability tongues in the (K,rho)--plane. We discuss possible resonance mechanisms that could account for the spacing with K of the stability tongues.Comment: 33 pages, 12 figure

    Regression Equations and Table for Estimating Numbers of Eggs in Jack Pine Budworm (Lepidoptera: Tortricidae) Egg Masses in Michigan

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    Three simple linear regression equations were developed to estimate the numbers of eggs in spruce budworm, Choristoneura fumiferana, egg masses in Michigan. One equation was developed for each of 2-row, 2- row + , and 3-row egg masses. A table of estimated numbers of eggs per egg mass is given for each of the three row types for egg mass lengths from 1 to 13 mm

    Encapsulation process sterilizes and preserves surgical instruments

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    Ethylene oxide is blended with an organic polymer to form a sterile material for encapsulating surgical instruments. The material does not bond to metal and can be easily removed when the instruments are needed

    Process for preparing sterile solid propellants Patent

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    Using ethylene oxide in preparation of sterilized solid rocket propellants and encapsulating material
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