160 research outputs found

    Adolescent Risk-Taking Behaviors and School Performance: Distinguishing the Experiences of Boys and Girls

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    Previous studies have examined the risk-taking behaviors of adolescents and their impact upon a variety of outcomes, yet comparatively few have addressed educational consequences. Using a nationally representative sample of American high school seniors, this study examines how risk-taking behaviors are associated with school performance, and how this relationship may vary by gender. Framed within the life-course perspective, the analyses reveal that while adolescent boys engage in significantly higher levels of delinquency and substance use, the consequences of such behavior appear to be greater for girls. The implications of these findings are discussed, as well as the gendered nature of risk-taking

    Transitions into Parenthood: Examining the Complexities of Childrearing

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    Around the globe, the very conceptualization of family is associated with the relationship between a parent and a child. The birth of a child represents both the end of one experience, and the beginning of another. Entry into parenthood represents a fundamental shift in family structure and family dynamics, wherein the child brings new responsibilities within the family and upon the larger society, particularly in regards to population issues. In order to better understand the transitions into parenthood, this multidisciplinary volume of CPFR will address such topics as: employment and fertility, childbearing desires versus childbearing outcomes, the social media construction of parenthood, gender differences in childrearing, parental discipline and child outcomes, among others. This volume will contain research on parenthood and parenting from around the world, and is intended to provide a more global perspective of these issues. Given that these topics range across various disciplines, a variety of theoretical and methodological approaches are utilized in the research herein

    Childbearing and the Changing Nature of Parenthood: The Contexts, Actors, and Experiences of Having Children

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    Around the globe, the very conceptualization of family is associated with the relationship between a parent and a child. The birth of a child represents both the end of one experience, and the beginning of another. Entry into parenthood represents a fundamental shift in family structure and family dynamics, wherein the child brings new responsibilities within the family and upon the larger society, particularly in regards to population issues. In order to better understand the transitions into parenthood, this multidisciplinary volume of CPFR will address such topics as: employment and fertility, childbearing desires versus childbearing outcomes, the social media construction of parenthood, gender differences in childrearing, parental discipline and child outcomes, among others. This volume will contain research on parenthood and parenting from around the world, and is intended to provide a more global perspective of these issues. Given that these topics range across various disciplines, a variety of theoretical and methodological approaches are utilized in the research herein

    Regulatory B Cells and Allergic Diseases

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    B cells are generally considered to positively regulate immune responses by producing antigen-specific antibodies. B cells are classified into classical CD5- conventional B cells and CD5+ B1 cells. The latter produce multi-specific autoantibodies and are thought to be involved in autoimmune diseases. However, evidence supporting a B cell negative regulatory function has accumulated over the past 30 years. Multiple reports have suggested that absence, or loss, of regulatory B cells exacerbates symptoms of both allergic (including contact hypersensitivity and anaphylaxis) and autoimmune (such as experimental autoimmune encephalomyelitis, chronic colitis, and collagen-induced arthritis) diseases, and in lupus-like models of autoimmunity. Regulatory B cells are characterized by production of the negative regulatory cytokines, IL-10 and TGF-β. IL-10-producing B cells were the first regulatory B cells to be recognized and were termed 'B10' cells. IL-10-producing regulatory B cells are of the CD19+CD5+IgMhiIgDloCD1dhi type. Recently, a TGF-β-producing regulatory B cell subset, Br3, has been shown to be related to immune tolerance in food allergies. Moreover, forkhead box P3 (Foxp3)-expressing B cells have also been identified in humans and may act as regulatory B cells (Bregs). The functional image of regulatory B cells is similar to that of regulatory T cells. Because of the proliferative and apoptotic responses of Br1 and Br3 cells in immune tolerance in non-IgE-mediated food allergy, reciprocal roles and counter-regulatory mechanisms of Br1 and Br3 responses are also suspected. Additionally, different roles for regulatory B and T cells at different time points during initiation and progression of autoimmune disease are described

    First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

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    Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

    Improving risk management for violence in mental health services: a multimethods approach

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    A gravitational-wave standard siren measurement of the Hubble constant

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    On 17 August 2017, the Advanced LIGO 1 and Virgo 2 detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system 3 . Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source 4-6 . This sky region was subsequently observed by optical astronomy facilities 7 , resulting in the identification 8-13 of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' 14-18 (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder' 19 : the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements 20,21 , while being completely independent of them. Additional standard siren measurements from future gravitationalwave sources will enable the Hubble constant to be constrained to high precision

    Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

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    The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society
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