16,335 research outputs found

    Satellite Power System. Concept development and evaluation program, volume 6: Construction and operations

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    The construction, operation, and maintenance requirements for a solar power satellite, including the space and ground systems, are reviewed. The basic construction guidelines are explained, and construction location options are discussed. The space construction tasks, equipment, and base configurations are discussed together with the operations required to place a solar power satellite in geosynchronous orbit. A rectenna construction technique is explained, and operation with the grid is defined. Maintenance requirements are summarized for the entire system. Key technology issues required for solar power satellite construction operations are defined

    Ab initio description of nonlinear dynamics of coupled microdisk resonators with application to self-trapping dynamics

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    Ab initio approach is used to describe the time evolution of the amplitudes of whispering gallery modes in a system of coupled microdisk resonators with Kerr nonlinearity. It is shown that this system demonstrates a transition between Josephson-like nonlinear oscillations and self-trapping behavior. Manifestation of this transition in the dynamics of radiative losses is studied.Comment: 10 pages, 5 figures, accepted for publication in Phys. Rev.

    Atlas of abundance and distribution patterns of ichthyoplankton from the Northeast Pacific Ocean and Bering Sea ecosystems: based on research conducted by the Alaska Fisheries Science Center (1972–1996)

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    This regional atlas summarizes and illustrates the distribution and abundance patterns of fish eggs and larvae of 102 taxa within 34 families found in the Northeast Pacific Ocean including the Bering Sea, Gulf of Alaska, and U.S. west coast ecosystems. Data were collected over a 20+ year period (1972–1996) by the Recruitment Processes Program of the Alaska Fisheries Science Center (AFSC). Ichthyoplankton catch records used in this atlas were generated from 11,379 tows taken during 100 cruises. For each taxon, general life history data are briefly summarized from the literature. Published information on distribution patterns of eggs and larvae are reviewed for the study area. Data from AFSC ichthyoplankton collections were combined to produce an average spatial distribution for each taxon. These data were also used to estimate mean abundance and percent occurrence by year and month, and relative abundance by larval length and season. Abundance from each tow was measured as catch per 10 m2 surface area. A larval distribution and abundance map was produced with a geographic information system using ArcInfo software. For taxa with identifiable pelagic eggs, distribution maps showing presence or absence of eggs are presented. Presence or absence of adults in the study area is mapped based on recent literature and data from AFSC groundfish surveys. Distributional records for adults and early life history stages revealed several new range extensions. (PDF file contains 288 pages.

    The Practitioner\u27s Corner: An exploration of municipal active living charter development and advocacy

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    Background: Numerous municipal active living-­‐related charters have been adopted to promote physical activity in Canada throughout the past decade. Despite this trend, there are few published critical examinations of the process through which charters are developed and used. Purpose: Thus, the purpose of this study was to establish greater understanding of active living charter development and advocacy. Methods: Semi-­‐structured interviews were conducted with eight primary contributors to different active living-­‐related charters across Ontario, Canada. Interview questions explored participants’ experiences developing and advocating for an active living charter. Interviews were analyzed using open, axial, and selective coding. Results and Conclusions: Participants consistently described a process whereby an impetus triggered the development of a charter, which was subsequently adopted by regional or municipal council. Continued advocacy to develop awareness of the charter and to promote desired outcomes in the community was valued and the capacity of the working group as well as the local political context played pivotal roles in determining how the charter was implemented. Outcomes were, however, only objectively evaluated in one case that was described – evaluation being a process that many participants thought was omitted in regard to their own charter. This work provides practical guidance for health professionals developing regional active living charters as a component of broader advocacy efforts

    Measurement of the 0.511 MeV gamma ray line from the Galactic Center

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    The detection of the 0.511 MeV electron positron annihilation line coming from the Galactic Center to provide the means to estimate the rate of positron production and to test some theoretical sources of positrons is addressed. The results of the measurements of the 0.511 MeV line flux made with a gamma ray experiment on board a stratospheric balloon are presented. The detector field of view looked at the galactic longitude range -31 deg l(II) +41 deg. The observed flux is 0.0067 (+ or - 0.0005) photons 1/cm(2)5 which is in very good agreement with the expected flux when assuming that the Galactic Center is a line source emitting uniformly

    Relational Aggression, Intimate Partner Violence, and Gender: An Exploratory Analysis

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    This study explores the effects of romantic relational aggression on intimate partner violence. The concept of relational aggression denotes a type of nonphysical aggression that is specific to relationships and that has only recently been recognized in the psychological literature. Using responses to the Conflict Tactics Scale from adults participating in the Project on Human Development in Chicago Neighborhoods, romantic relational aggression is examined with regard to male and female intimate partner violence perpetration and victimization. Results indicate that romantic relational aggression is a predictor of partner violence perpetration and victimization among both males and females

    Clarifying the Effects of Neighborhood Context on Violence “Behind Closed Doors”

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    Research on neighborhood-level effects on intimate partner violence (IPV) has expanded significantly in the past two decades. However, to date, studies have been unable to disentangle compositional and contextual effects on IPV and have rarely considered the social mechanisms that might link neighborhood conditions to IPV. Using data from the Project on Human Development in Chicago Neighborhoods, this study considers individual and contextual influences on violence between partners, and examines the effects of disadvantage and collective efficacy on this type of behavior. Results indicate that neighborhood disadvantage significantly increases and collective efficacy significantly decreases IPV after controlling for individual-level correlates. Our findings add to a growing body of evidence suggesting that as with street crime, neighborhood disadvantage also exacerbates rates of IPV. However, unlike street crime, the impact of disadvantage on IPV does not appear to be mediated by collective efficacy. Understanding how collective efficacy affects violence between partners remains an open issue

    Immigration and Intimate Partner Violence: Exploring the Immigrant Paradox

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    Recent evidence indicates that contrary to some criminological theories, immigrants are less violent than native-born Americans. The relationship between immigrant status and reduced violence appears to hold at both the individual and neighborhood levels of analysis. This phenomenon has been referred to as the immigrant or Latino paradox. It has been suggested, although rarely examined, that cultural differences and strong social networks among immigrants account for their lower violence rates. These factors even appear strong enough to counterbalance the crime-promoting effects of economic disadvantage. This study investigates whether such patterns extend to intimate partner violence. Consistent with research on other forms of violence, we find that neighborhoods with greater concentrations of immigrants have lower levels of intimate partner violence. This relationship appears to be partially mediated by cultural norms and social ties

    Unpacking distinction within mobility : social prestige and international students

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    Author thanks the Social Sciences and Humanities Research Council of Canada (SSHRC) for their funding on this projecThis paper investigates the complex ways in which young people engage in social distinction within international mobility. The study offers novel conceptual and empirical insights by examining how distinction and social advantage is reproduced through short‐term student mobility from the Global North to the Global South. In doing so, it elucidates the iterative process of distinction‐making within mobility and argues that young mobile people negotiate a tension between different forms of distinction. Specifically, it unpacks and conceptualises distinction into dual categories—collective and individual—and suggests that students alternate and waver between these categories in order to both validate and elevate their position within a mobility hierarchy. The paper also considers how particular places are viewed as more distinctive and affording greater gains in cultural and symbolic capital. It concludes with future interrogations and ways forward for research on international mobility and distinction.PostprintPeer reviewe
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