17,124 research outputs found

    The `Periodic Nulls' of Radio Pulsar J1819+1305

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    We present a single-pulse study of the four-component pulsar J1819+1305, whose ``null'' pulses bunch at periodic intervals of around 57 times the rotation period. The emission bursts between the null bunches exhibit characteristic modulations at two shorter periodicities of approximately 6.2 and 3 times the rotation period, the former found largely in the two outer components, and the latter only in the first component. Many bursts commence with bright emission in second component, exhibit positive six-period drift across the full profile width, and end with 3-period modulation in the leading component. The 57-period cycle can be modelled geometrically as a sparsely filled subbeam carousel with nulls appearing whenever our line of sight intersects a circulating empty region. This interpretation is compatible with other recent evidence for periodic, carousel-related nulling and appears to support the physics of a polar-gap emission model for ``drifting'' subpulses, but the subtle structure of the emission bursts defies an easy explanation.Comment: 8 pages, 9 figure

    Lyapunov exponents for products of complex Gaussian random matrices

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    The exact value of the Lyapunov exponents for the random matrix product PN=ANAN1...A1P_N = A_N A_{N-1}...A_1 with each Ai=Σ1/2GicA_i = \Sigma^{1/2} G_i^{\rm c}, where Σ\Sigma is a fixed d×dd \times d positive definite matrix and GicG_i^{\rm c} a d×dd \times d complex Gaussian matrix with entries standard complex normals, are calculated. Also obtained is an exact expression for the sum of the Lyapunov exponents in both the complex and real cases, and the Lyapunov exponents for diffusing complex matrices.Comment: 15 page

    Identification of Genes Associated with Water Restriction Expressed in the Renal Cortex and Hypothalamus in Cattle

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    The short-term objective of this study is to discover genes associated with water restriction expressed in the renal cortex and hypothalamus in beef calves. The long-term goal is to understand genes and pathways important for thirst response in cattle. This knowledge may lead to discovery of genetic variants associated with water intake. Identification of animals with genetic potential to grow and thrive under drought conditions would be an asset to beef producers and communities which rely on beef production for a large part of their livelihoods. Both selected tissue types are known to be involved in response to hypertonicity (e.g., water restriction or dehydration)

    Developmental perturbation induced by maternal asthma during pregnancy: The short- and long-term impacts on offspring

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    Extent: 8p.Maternal asthma is a common disease to complicate human pregnancy. Epidemiological studies have identified that asthma during pregnancy increases the risk of a number of poor outcomes for the neonate including growth restriction, lower birthweight, preterm delivery, neonatal resuscitation, and stillbirth. Asthma therefore represents a significant health burden to society and could have an impact on the lifelong health of the children of women with asthma. Our research has identified that maternal asthma in pregnancy induces placental dysfunction and developmental perturbation in the fetus in a sex specific manner. These alterations in development could increase the risk of metabolic disease in adulthood of children of asthmatic mothers, especially females. In this paper, we will discuss the evidence currently available that supports the hypothesis that children of mothers with asthma may be at risk of lifelong health complications which include diabetes and hypertension.Vicki L. Clifton, Michael Davies, Vivienne Moore, Ian M. R. Wright, Zainab Ali, and Nicolette A. Hody

    Developmental perturbation induced by maternal asthma during pregnancy: The short- and long-term impacts on offspring

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    Extent: 8p.Maternal asthma is a common disease to complicate human pregnancy. Epidemiological studies have identified that asthma during pregnancy increases the risk of a number of poor outcomes for the neonate including growth restriction, lower birthweight, preterm delivery, neonatal resuscitation, and stillbirth. Asthma therefore represents a significant health burden to society and could have an impact on the lifelong health of the children of women with asthma. Our research has identified that maternal asthma in pregnancy induces placental dysfunction and developmental perturbation in the fetus in a sex specific manner. These alterations in development could increase the risk of metabolic disease in adulthood of children of asthmatic mothers, especially females. In this paper, we will discuss the evidence currently available that supports the hypothesis that children of mothers with asthma may be at risk of lifelong health complications which include diabetes and hypertension.Vicki L. Clifton, Michael Davies, Vivienne Moore, Ian M. R. Wright, Zainab Ali, and Nicolette A. Hody

    Developmental perturbation induced by maternal asthma during pregnancy: The short- and long-term impacts on offspring

    Get PDF
    Extent: 8p.Maternal asthma is a common disease to complicate human pregnancy. Epidemiological studies have identified that asthma during pregnancy increases the risk of a number of poor outcomes for the neonate including growth restriction, lower birthweight, preterm delivery, neonatal resuscitation, and stillbirth. Asthma therefore represents a significant health burden to society and could have an impact on the lifelong health of the children of women with asthma. Our research has identified that maternal asthma in pregnancy induces placental dysfunction and developmental perturbation in the fetus in a sex specific manner. These alterations in development could increase the risk of metabolic disease in adulthood of children of asthmatic mothers, especially females. In this paper, we will discuss the evidence currently available that supports the hypothesis that children of mothers with asthma may be at risk of lifelong health complications which include diabetes and hypertension.Vicki L. Clifton, Michael Davies, Vivienne Moore, Ian M. R. Wright, Zainab Ali, and Nicolette A. Hody

    Quark-Gluon String Model Description of Baryon Production in K^{\pm}N Interactions

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    The process of baryon production in K p collisions at high energies is considered in the framework of the Quark-Gluon String Model. The contribution of the string-junction mechanism to the strange baryon production is analysed. The results of numerical calculations are in reasonable agreement with the data on inclusive spectra of p, Lambda, bar{Lambda}, and on the bar{Lambda}/Lambda asymmetry. The predictions for Xi and Omega baryons are presented.Comment: 19 pages, 7 figure

    Excitation spectrum of a two-component Bose-Einstein condensate in a ring potential

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    A mixture of two distinguishable Bose-Einstein condensates confined in a ring potential has numerous interesting properties under rotational and solitary-wave excitation. The lowest-energy states for a fixed angular momentum coincide with a family of solitary-wave solutions. In the limit of weak interactions, exact diagonalization of the many-body Hamiltonian is possible and permits evaluation of the complete excitation spectrum of the system.Comment: 4 pages, 1 figur

    (7aR*,12bS*)-8,12b-Dihydro-7aH-indeno­[1′,2′:5,6][1,4]selenazino[2,3,4-ij]quinolin-13-ium hydrogen sulfate

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    In the title compound, C18H14NSe+·HSO4 −, the cyclo­pentene ring in the cation has an envelope conformation while the central six-membered 1,4-selenazine ring adopts a sofa conformation. The dihedral angle between the planes of the terminal benzene rings is 68.08 (11)°. In the crystal, the anions form chains along the c axis through O—H⋯O hydrogen bonds. Weak C—H⋯O and C—H⋯π hydrogen bonds, as well as attractive Se⋯Se [3.5608 (8) Å] inter­actions, further consolidate the crystal structure
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