86 research outputs found

    Radiation protection guidelines for space missions

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    NASA's current radiation protection guidelines date from 1970, when the career limit was set at 400 rem. Today, using the same approach, but with the current risk estimates, a considerably lower career limit would obtain. Also, there is considerably more information about the radiation environments to be experienced in different missions than previously. Since 1970 women have joined the ranks. For these and other reasons it was necessary to reexamine the radiation protection guidelines. This task was undertaken by the National Council on Radiation Protection and Measurements Scientific Committee 75 (NCRP SC 75). Below the magnetosphere the radiation environment varies with altitude and orbit inclination. In outer space missions galactic cosmic rays, with the small but important heavy ion component, determine the radiation environment. The new recommendations for career dose limits, based on lifetime excess risk of cancer mortality, take into account age at first exposure and sex. The career limits range from 100 rem (4.0Sv) for a 24 year old female to 400 rem for a 55 year old male compared to the previous single limit of 400 rem (4.0 Sv). The career limit for the lens of the eye was reduced from 600 to 400 rem (6.0 to 4.0 Sv.

    Toward a descriptive model of solar particles in the heliosphere

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    During a workshop on the interplanetary charged particle environment held in 1987, a descriptive model of solar particles in the heliosphere was assembled. This model includes the fluence, composition, energy spectra, and spatial and temporal variations of solar particles both within and beyong 1 AU. The ability to predict solar particle fluences was also discussed. Suggestions for specific studies designed to improve the basic model were also made

    Whole-mount in situ hybridization in the Rotifer Brachionus plicatilis representing a basal branch of lophotrochozoans

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    In order to broaden the comparative scope of evolutionary developmental biology and to refine our picture of animal macroevolution, it is necessary to establish new model organisms, especially from previously underrepresented groups, like the Lophotrochozoa. We have established the culture and protocols for molecular developmental biology in the rotifer species Brachionus plicatilis MĂŒller (Rotifera, Monogononta). Rotifers are nonsegmented animals with enigmatic basal position within the lophotrochozoans and marked by several evolutionary novelties like the wheel organ (corona), the median eye, and the nonpaired posterior foot. The expression of Bp-Pax-6 is shown using whole-mount in situ hybridization. The inexpensive easy culture and experimental tractability of Brachionus as well as the range of interesting questions to which it holds the key make it a promising addition to the “zoo” of evo-devo model organisms

    Socio-economic voter profile and motives for Islamist support in Morocco

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    Based on an original dataset of merged electoral and census data, this article is a study of electoral support for the Islamist Party in Morocco in the 2002 and 2007 elections. It differentiates between the clientelistic, grievance and horizontal network type of supporters. We disentangle these profiles empirically on the basis of the role of education, wealth and exclusion for Islamist votes. We find no evidence of the clientelistic profile, but a shift from grievance in 2002 to a horizontal network profile in 2007. World Values Survey individual level data are used as a robustness check, yielding similar results. Qualitative evidence on a changing mobilization pattern of the party between 2002 and 2007 supports our conclusions

    Strictly Fantasy: The Cultural Roots of Tabletop Role-Playing Games (Studies in Gaming)

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    Role-playing games seemed to appear of nowhere in the early 1970s and have been a quiet but steady presence in American culture ever since. This new look at the hobby searches for the historical origins of role-playing games deep in the imaginative worlds of Western culture. It looks at the earliest fantasy stories from the nineteenth and twentieth centuries, at the fans--both readers and writers--who wanted to bring them to life, at the Midwestern landscape and the middle-class households that were the hobby\u27s birthplace, and at the struggle to find meaning and identity amidst cultural conflicts that drove many people into these communities of play. This book also addresses race, religion, gender, fandom, and the place these games have within American capitalism. All the paths of this journey are connected by the very quality that has made fantasy role-playing so powerful: it binds the limitless imagination into a strict framework of rules. Far from being an accidental offshoot of marginalized fan communities, role-playing games\u27 ability to hold contradictions in dynamic, creative tension made them a necessary and central product of the twentieth century.https://encompass.eku.edu/fs_books/1045/thumbnail.jp

    Irreversible Plastid Loss in Euglena gracilis

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    Neoliberal globalization and trade unionism: toward radical political unionism?

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    This article revisits the question of changing forms of trade unionism within the context of neoliberal globalization. While broadly accepting the argument that globalization might encourage the development of more radical forms of unionism as survival strategies, it argues that such radicalism cannot be understood satisfactorily by the term social movement unionism (SMU). This is due to over-reliance on theories of the new social movements (NSMs), which produce a largely de-classed and de-politicized perspective. The article uses insights gained from theoretical work on protest and labour movement development to bring the state back into the analysis and applies this analysis to oppositional trade union practice in a variety of institutional contexts. It concludes by making a case for understanding contemporary forms of oppositional trade union strategy through the term radical political unionism which takes account of both its social and political determinants as well as the agency role played by political leaderships
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