67,575 research outputs found

    Coaxial cable stripping device facilitates RF cabling fabrication

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    Coaxial cable stripping device assures clean, right angled shoulder for RF cable connector fabrication. This method requires minimal skill and creates a low voltage standing wave ratio and mechanical stability in the interconnecting RF Cables

    Quantum key distribution over 122 km of standard telecom fiber

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    We report the first demonstration of quantum key distribution over a standard telecom fiber exceeding 100 km in length. Through careful optimisation of the interferometer and single photon detector, we achieve a quantum bit error ratio of 8.9% for a 122km link, allowing a secure shared key to be formed after error correction and privacy amplification. Key formation rates of up to 1.9 kbit/sec are achieved depending upon fiber length. We discuss the factors limiting the maximum fiber length in quantum cryptography

    Sexual Orientation Differences in the Relationship Between Victimization and Hazardous Drinking Among Women in the National Alcohol Survey

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    This study examined relationships between past experiences of victimization (sexual abuse and physical abuse in childhood, sexual abuse and physical abuse in adulthood, and lifetime victimization) and hazardous drinking among sexual minority women compared to exclusively heterosexual women. Data were from 11,169 women responding to sexual identity and sexual behavior questions from three National Alcohol Survey waves: 2000 (n = 3,880), 2005 (n = 3,464), and 2010 (n = 3,825). A hazardous drinking index was constructed from five dichotomous variables (5+ drinking in the past year, drinking two or more drinks daily, drinking to intoxication in the past year, two or more lifetime dependence symptoms, and two or more lifetime drinking-related negative consequences). Exclusively heterosexual women were compared with three groups of sexual minority women: lesbian, bisexual, and women who identified as heterosexual but reported same-sex partners. Each of the sexual minority groups reported significantly higher rates of lifetime victimization (59.1% lesbians, 76% bisexuals, and 64.4% heterosexual women reporting same-sex partners) than exclusively heterosexual women (42.3%). Odds for hazardous drinking among sexual minority women were attenuated when measures of victimization were included in the regression models. Sexual minority groups had significantly higher odds of hazardous drinking, even after controlling for demographic and victimization variables: lesbian (OR [sub]adj[sub] = 2.0, CI = 1.1–3.9, p \u3c .01; bisexual (OR [sub]adj[sub] = 1.8, CI = 1.0–3.3, p \u3c .05; heterosexual with same-sex partners (ORadj = 2.7; CI = 1.7–4.3, p \u3c .001). Higher rates of victimization likely contribute to, but do not fully explain, higher rates of hazardous drinking among sexual minority women. (PsycINFO Database Record (c) 2013 APA, all rights reserved) (journal abstract)

    Family-focused treatment for childhood depression: model and case illustrations

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    Although the evidence base for treatment of depressive disorders in adolescents has strengthened in recent years, less is known about the treatment of depression in middle to late childhood. A family-based treatment may be optimal in addressing the interpersonal problems and symptoms frequently evident among depressed children during this developmental phase, particularly given data indicating that attributes of the family environment predict recovery versus continuing depression among depressed children. Family-Focused Treatment for Childhood Depression (FFT-CD) is designed as a 15-session family treatment with both the youth and parents targeting two putative mechanisms involved in recovery: (a) enhancing family support, specifically decreasing criticism and increasing supportive interactions; and (b) strengthening specific cognitive-behavioral skills within a family context that have been central to CBT for depression, specifically behavioral activation, communication, and problem solving. This article describes in detail the FFT-CD protocol and illustrates its implementation with three depressed children and their families. Common themes/challenges in treatment included family stressors, comorbidity, parental mental health challenges, and inclusion/integration of siblings into sessions. These three children experienced positive changes from pre- to posttreatment on assessor-rated depressive symptoms, parent- and child-rated depressive symptoms, and parent-rated internalizing and externalizing symptoms. These changes were maintained at follow-up evaluations 4 and 9 months following treatment completion.K23 MH101238 - NIMH NIH HHS; R01 MH082856 - NIMH NIH HHS; R01 MH082861 - NIMH NIH HH

    Lagrangian versus Quantization

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    We discuss examples of systems which can be quantized consistently, although they do not admit a Lagrangian description.Comment: 8 pages, no figures; small corrections, references adde

    Interferometric Upper Limits on Millimeter Polarization of the Disks around DG Tau, GM Aur, and MWC 480

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    Millimeter-wavelength polarization measurements offer a promising method for probing the geometry of magnetic fields in circumstellar disks. Single dish observations and theoretical work have hinted that magnetic field geometries might be predominantly toroidal, and that disks should exhibit millimeter polarization fractions of 2-3%. While subsequent work has not confirmed these high polarization fractions, either the wavelength of observation or the target sources differed from the original observations. Here we present new polarimetric observations of three nearby circumstellar disks at 2" resolution with the Submillimeter Array (SMA) and the Combined Array for Research in Millimeter Astronomy (CARMA). We reobserve GM Aur and DG Tau, the systems in which millimeter polarization detections have been claimed. Despite higher resolution and sensitivity at wavelengths similar to the previous observations, the new observations do not show significant polarization. We also add observations of a new HAeBe system, MWC 480. These observations demonstrate that a very low (100 AU) scales in bright circumstellar disks. We suggest that high-resolution observations may be worthwhile to probe magnetic field structure on linear distances smaller than the disk scale height, as well as in regions closer to the star that may have larger MRI-induced magnetic field strengths.Comment: 7 pages, 3 figures, accepted for publication in A

    Minimizing Bias in Biomass Allometry: Model Selection and Log‐Transformation of Data

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    Nonlinear regression is increasingly used to develop allometric equations for forest biomass estimation (i.e., as opposed to the traditional approach of log‐transformation followed by linear regression). Most statistical software packages, however, assume additive errors by default, violating a key assumption of allometric theory and possibly producing spurious models. Here, we show that such models may bias stand‐level biomass estimates by up to 100 percent in young forests, and we present an alternative nonlinear fitting approach that conforms with allometric theory
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