3,514 research outputs found

    Search for positron annihilation line and continuum radiation from the Galactic Center

    Get PDF
    Our balloon-borne germain gamma-ray telescope was flown over Alice Springs, Australia, on 1984 November 20 to search for the 511 keV positron annihilation line from the Galactic Center. The measured line flux at Earth was (0.6 + or - 4.4) x 0.001 ph/sq cm/s indicating that the source was still in a low or off state

    Girls in the 'Hood: The Importance of Feeling Safe

    Get PDF
    Looks at how adolescent girls benefited from moving out of extremely poor, high-crime neighborhoods into lower poverty areas through the Moving to Opportunity program. Focuses on reduced "female fear" as one reason why girls benefited more than boys

    Albinism in the domestic cat (Felis catus) is associated with a tyrosinase (TYR) mutation

    Get PDF
    Albino phenotypes are documented in a variety of species including the domestic cat. As albino phenotypes in other species are associated with tyrosinase (TYR) mutations, TYR was proposed as a candidate gene for albinism in cats. An Oriental and Colourpoint Shorthair cat pedigree segregating for albinism was analysed for association with TYR by linkage and sequence analyses. Microsatellite FCA931, which is closely linked to TYR and TYR sequence variants were tested for segregation with the albinism phenotype. Sequence analysis of genomic DNA from wild-type and albino cats identified a cytosine deletion in TYR at position 975 in exon 2, which causes a frame shift resulting in a premature stop codon nine residues downstream from the mutation. The deletion mutation in TYR and an allele of FCA931 segregated concordantly with the albino phenotype. Taken together, our results suggest that the TYR gene corresponds to the colour locus in cats and its alleles, from dominant to recessive, are as follows: C (full colour) > c(b) (burmese) ≥ c(s) (siamese) > c (albino)

    Inequality and Procedural Justice in Social Dilemmas

    Get PDF
    This study investigates the influence of resource inequality and the fairness of the allocation procedure of unequal resources on cooperative behavior in social dilemmas. We propose a simple formal behavioral model that incorporates conflicting selfish and social motivations. This model allows us to predict how inequality influences cooperative behavior. Allocation of resources is manipulated by three treatments that vary in terms of procedural justice: allocating resources randomly, based on merit, and based on ascription. As predicted, procedural justice influences cooperation significantly. Moreover, gender is found to be an important factor interacting with the association between procedural justice and cooperative behavior.

    GRIS observations of the galactic center and the gamma ray galactic diffuse continuum

    Get PDF
    On two flights in 1988, the Gamma-Ray Imaging Spectrometer (GRIS) discovered the galactic center in a high state (greater than 1 x 10(exp -3) ph/(sq cm sec)) of positron annihilation line emission (511 keV) after nearly a decade of failed attempts to confirm the exciting early results of balloon and satellite instruments. These two flights represented the first flights of a new generation of high resolution germanium spectrometers designed to achieve significantly greater sensitivity for astrophysical observations. During the fall flight, an observation of the galactic plane at 335 degrees longitude was also performed. This observation showed a very low level of 511 keV emission (2 +/- 1 x 10(exp -4) ph/(sq cm sec)), confirming the galactic center origin of the line, and a high level of hard x-ray and gamma-ray continuum emission (1 x 10(exp -4) ph/(sq cm sec keV) at 100 keV), which we attribute to galactic diffuse emission. Improved fits to the spectrum of the galactic center are presented with the proposed diffuse component subtracted. We conclude that our galactic center continuum spectrum is consistent with the sum of the 1E1740.7-2942 spectrum observed by SIGMA/GRANAT and our 1 = 335 degree galactic plane spectrum. The predicted diffuse flux should be easily measurable by the Oriented Scintillation Spectrometer Experiment (OSSE) experiment on the Gamma Ray Observatory (GRO)

    Spectroscopy from 2 to 200 keV

    Get PDF
    The astrophysical processes responsible for line and continuum emission in the spectra range 2 keV to 200 keV are examined from the viewpoint of designing a spectrometer which would operate in this regime. Phenomena considered include fluorescent line radiation in X-ray binaries, magnetically shifted iron lines and cyclotron emission from neutron star surfaces, line emission from cosmically abundant elements in thermal plasmas, and nuclear deexcitation lines in fresh nucleosynthetically produced matter. An instrument consisting of a approximately 10 sq cm array of planar germanium detectors surrounded by a large sodium-iodide anticoincidence shield is described and projected background rates and sensitivities are considered. A sample observing program for a two-day shuttle-based mission is included as an example of the wide range of scientific questions which could be addressed by such an instrument

    Building Psychosocial Assets And Wellbeing Among Adolescent Girls: A Randomized Controlled Trial

    Get PDF
    We conducted a randomized controlled trial of a 5-month resilience-based program (Girls First Resilience Curriculum or RC) among 2308 rural adolescent girls at 57 government schools in Bihar, India. Local women with at least a 10th grade education served as group facilitators. Girls receiving RC improved more (vs. controls) on emotional resilience, self-efficacy, social-emotional assets, psychological wellbeing, and social wellbeing. Effects were not detected on depression. There was a small, statistically significant negative effect on anxiety (though not likely clinically significant). Results suggest psychosocial assets and wellbeing can be improved for girls in high-poverty, rural schools through a brief school-day program. To our knowledge, this is one of the largest developing country trials of a resilience-based school-day curriculum for adolescents. (C) 2015 The Authors. Published by Elsevier Ltd on behalf of The Foundation for Professionals in Services for Adolescents. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    Fostering Emotional, Social, Physical And Educational Wellbeing In Rural India: The Methods Of A Multi-Arm Randomized Controlled Trial Of Girls First

    Get PDF
    Background: There are 600 million girls in low and middle income countries (LMICs), many of whom are at great risk for poor health and education. There is thus great need for programs that can effectively improve wellbeing for these girls. Although many interventions have been developed to address these issues, most focus on health and education without integrating attention to social and emotional factors. This omission is unfortunate, as nascent evidence indicates that these factors are closely related to health and education. This paper describes the methods of a 4-arm randomized controlled trial among 3,560 adolescent girls in rural Bihar, India that tested whether adding an intervention targeting social-emotional issues (based on a “resilience framework”) to an adolescent health intervention would improve emotional, social, physical, and educational wellbeing to a greater extent than its components and a control group. Study arms were: (1) Girls First, a combination of the Girls First Resilience Curriculum (RC) and the Girls First Health Curriculum (HC); (2) Girls First Resilience Curriculum (RC) alone; (3) Girls First Health Curriculum (HC) alone; and (4) a school-as-usual control group (SC). Methods: Seventy-six schools were randomized (19 per condition) and 74 local women with a tenth grade education were trained and monitored to facilitate the program. Quantitative data were collected from 3,560 girls over 4 assessment points with very low rates of participant attrition. Qualitative assessments were conducted with a subset of 99 girls and 27 facilitators. Results and conclusions: In this article, we discuss guiding principles that facilitated trial implementation, including integrating diverse local and non-local sources of knowledge, focusing on flexibility of planning and implementation, prioritizing systematic measurement selection, and striking a balance between scientific rigor and real-world feasibility

    XTE J1739-302: An Unusual New X-ray Transient

    Get PDF
    A new x-ray transient, designated XTE J1739-302, was discovered with the Proportional Counter Array (PCA) on the Rossi X-ray Timing Explorer (RXTE) in data from 12 August 1997. Although it was the brightest source in the Galactic Center region while active (about 3.0 x 10^-9 ergs/cm2/s from 2 to 25 keV), it was only observed on that one day; it was not detectable nine days earlier or two days later. There is no known counterpart at other wavelengths, and its proximity to the Galactic Center will make such an identification difficult due to source confusion and extinction. The x-ray spectrum and intensity suggest a giant outburst of a Be/neutron star binary, although no pulsations were observed and the outburst was shorter than is usual from these systems.Comment: 11 pages incorporating 6 figures, AAStex; accepted for The Astrophysical Journal, Part 2 (Letters

    A coded aperture imaging system optimized for hard X-ray and gamma ray astronomy

    Get PDF
    A coded aperture imaging system was designed for the Gamma-Ray imaging spectrometer (GRIS). The system is optimized for imaging 511 keV positron-annihilation photons. For a galactic center 511-keV source strength of 0.001 sq/s, the source location accuracy is expected to be + or - 0.2 deg
    corecore