1,098 research outputs found

    The Effects of GDP Per Capita on Infant Mortality Rates

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    We investigate the influence that the Growth Domestic Product (GDP) has upon the infant mortality rate. Our study comes from research from World Development Indicators from the Databank. The results from our regression explain 87.17% of total variation of infant mortality from the variables used. Our findings showed that GDP is negatively correlated with infant mortality. The findings are consistent with previous studies on the determinants of infant mortality rates

    Low serum vitamin D is associated with axial length and risk of myopia in young children

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    The aim of the study was to investigate the relationship between serum 25(OH)D levels and axial length (AL) and myopia in 6-year-old children. A total of 2666 children aged 6 years participating in the birth-cohort study Generation R underwent a stepwise eye examination. First, presenting visual acuity (VA) and AL were performed. Second, automated cycloplegic refraction was measured if LogMAR VA > 0.1. Serum 25-hydroxyvitamin D [25(OH)D] was determined from blood using liquid chromatography/tandem mass spectrometry. Vitamin D related SNPs were determined with a SNP array; outdoor exposure was assessed by questionnaire. The relationships between 25(OH)D and AL or myopia were investigated using linear and logistic regression analysis. Average 25(OH)D concentration was 68.8 nmol/L (SD ± 27.5; range 4–211); average AL 22.35 mm (SD ± 0.7; range 19.2–25.3); and prevalence of myopia 2.3 % (n = 62). After adjustment for covariates, 25(OH)D concentration (per 25 nmol/L) was inversely associated with AL (β −0.043; P < 0.01), and after additional adjusting for time spent outdoors (β −0.038; P < 0.01). Associations were not different between European and non-European children (β −0.037 and β −0.039 respectively). Risk of myopia (per 25 nmol/L) was OR 0.65 (95 % CI 0.46–0.92). None of the 25(OH)D related SNPs showed an association with AL or myopia. Lower 25(OH)D concentration in serum was associated with longer AL and a higher risk of myopia in these young children. This effect appeared independent of outdoor exposure and may suggest a more direct role for 25(OH)D in myopia pathogenesis

    Decoherence dynamics of a qubit coupled to a quantum two-level system

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    We study the decoherence dynamics of a qubit coupled to a quantum two-level system (TLS) in addition to its weak coupling to a background environment. We analyze the different regimes of behaviour that arise as the values of the different parameters are varied. We classify those regimes as two weak-coupling regimes, which differ by the relation between the qubit and TLS decoherence times, and a strong-coupling one. We also find analytic expressions describing the decoherence rates in the weak-coupling regimes, and we verify numerically that those expressions have a rather wide range of validity. Along with obtaining the above-mentioned results, we address the questions of qubit-TLS entanglement and the additivity of multiple TLS contributions. We also discuss the transition from weak to strong coupling as the parameters are varied, and we numerically determine the location of the boundary between the two regimes.Comment: 9 pages (two-column), 3 figure

    A particle system with explosions: law of large numbers for the density of particles and the blow-up time

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    Consider a system of independent random walks in the discrete torus with creation-annihilation of particles and possible explosion of the total number of particles in finite time. Rescaling space and rates for diffusion/creation/annihilation of particles, we obtain a stong law of large numbers for the density of particles in the supremum norm. The limiting object is a classical solution to the semilinear heat equation u_t =u_{xx} + f(u). If f(u)=u^p, 1<p \le 3, we also obtain a law of large numbers for the explosion time

    Estimation of biomass of horse mackerel (Trachurus trachurus L.) in northern-Spain ( Nortbern IXa and VIIIc ) using the daily egg production method.

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    In order to estimate the spawning stock biomass of horse mackerel in the North Atlantic Spanish waters, a series of egg and adult cruises were carried out by lEO (Instituto Español de Oceanografía) and AZTI -SIO (Instituto de Investigación y Tecnología para la Oceanografía, Pesca y Alimentación) . The survey was carried out from 23 April to 25 May 1992. A total of 627 plankton samples and 37 adults samples were collected. A total daily egg production of 3.3 X 1012 egg (SE = 7.26 X 1011 , CV = 0.22) was estimated for the whole area sarnpled (ICES Division Vlllc and subdivision northern IXa north). The estirnate of horse mackerel spawning biornass ranged from 486,549 tons (CV = 0.34, when using adult pararneter estirnates exclusively frorn the Spanish survey, down to 368,814 tn (C = 0.32), when alternatively using an estimate of relative batch fecundity from the southern region of horse rnackerel western stock

    Patterning the neuronal cells via inkjet printing of self-assembled peptides on silk scaffolds

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    The patterning of neuronal cells and guiding neurite growth are important for neuron tissue engineering and cell-based biosensors. In this paper, inkjet printing has been employed to pattern self-assembled I3QGK peptide nanofibers on silk substrates for guiding the growth of neuron-like PC12 cells. Atomic force microscopy (AFM) confirmed the dynamic self-assembly of I3QGK into nanofiber structures. The printed self-assembled peptide strongly adheres to regenerated silk fibroin (RSF) substrates through charge-charge interactions. It was observed that in the absence of I3QGK, PC12 cells exhibited poor attachment to RSF films, while for RSF surfaces coated or printed with peptide nanofibers, cellular attachment was significantly improved in terms of both cell density and morphology. AFM results revealed that peptide nanofibers can promote the generation of axons and terminal buttons of PC12 cells, indicating that I3QGK nanofibers not only promote cellular attachment but also facilitate differentiation into neuronal phenotypes. Inkjet printing allows complex patterning of peptide nanofibers onto RSF substrates, which enabled us to engineer cell alignment and provide an opportunity to direct axonal development in vitro. The live/dead assay showed that printed I3QGK patterns exhibit no cytotoxicity to PC12 cells demonstrating potential for future nerve tissue engineering applications

    X-boson cumulant approach to the periodic Anderson model

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    The Periodic Anderson Model (PAM) can be studied in the infinite U limit by employing the Hubbard X operators to project out the unwanted states. We have already studied this problem employing the cumulant expansion with the hybridization as perturbation, but the probability conservation of the local states (completeness) is not usually satisfied when partial expansions like the Chain Approximation (CHA) are employed. Here we treat the problem by a technique inspired in the mean field approximation of Coleman's slave-bosons method, and we obtain a description that avoids the unwanted phase transition that appears in the mean-field slave-boson method both when the chemical potential is greater than the localized level Ef at low temperatures (T) and for all parameters at intermediate T.Comment: Submited to Physical Review B 14 pages, 17 eps figures inserted in the tex

    Ultra-processed food consumption is associated with renal function decline in older adults: A prospective cohort study

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    Ultra-processed food (UPF) consumption has been associated with increased risk of cardiovascular risk factors and mortality. However, little is known on the UPF effect on renal function. The aim of this study is to assess prospectively the association between consumption of UPF and renal function decline. This is a prospective cohort study of 1312 community-dwelling individuals aged 60 and older recruited during 2008–2010 and followed up to December 2015. At baseline, a validated dietary history was obtained. UPF was identified according to NOVA classification. At baseline and at follow-up, serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) levels were ascertained and changes were calculated. A combined end-point of renal decline was considered: SCr increase or eGFR decreased beyond that expected for age. Logistic regression with adjustment for potential confounders was performed. During follow-up, 183 cases of renal function decline occurred. The fully adjusted odds ratios (95% CI) of renal function decline across terciles of percentage of total energy intake from UPF were 1.56 (1.02–2.38) for the second tercile, and 1.74 (1.14–2.66) for the highest tercile; p-trend was 0.026. High UPF consumption is independently associated with an increase higher than 50% in the risk of renal function decline in Spanish older adults
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