1,820 research outputs found

    Analog tree-organized multiplexer

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    An analog tree-organized multiplexer (ATOM) which is intended for use in the telemetry system of an interplanetary spacecraft is designed. The ATOM will be fabricated by a monolithic, dielectric isolation process, and will contain silicon junction field effect transistors (JFET) as the active elements. The effect of the radiation environment on the performance of the ATOM is analyzed. The result indicates that the expected radiation environment will cause only minor changes in the preradiation characteristics of ATOM. The JFET in the ATOM is designed to meet the electrical requirements when fabricated by either the double poly-dielectric isolation process or the raised dielectric isolation process. The effect of the heat treatment required for the dielectric isolation process on the diffusion profile of the JFET is described. The layout of the ATOM circuit for fabrication by either the double poly or raised dielectric isolation process is also given

    Caltech Faint Galaxy Redshift Survey XV: Classification of Galaxies with 0.2 < z < 1.1 in the Hubble Deep Field (North) and its Flanking Fields

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    To circumvent the spatial effects of resolution on galaxy classification, the images of 233 objects of known redshift in the Hubble Deep Field (HDF) and its Flanking Fields (FF) that have redshifts in the range 0.20 < z < 1.10 were degraded to the resolution that they would have had if they were all located at a redshift z= 1.00. As in paper XIV of the present series, the effects of shifts in rest wavelength were mitigated by using R-band images for the classification of galaxies with 0.2 < z < 0.6 and I-band images for objects with redshifts 0.6 < z < 1.1. A special effort was made to search for bars in distant galaxies. The present data strongly confirm the previous conclusion that the Hubble tuning fork diagram only provides a satisfactory framework for the classification of galaxies with z ~< 0.3. More distant disk galaxies are often difficult to shoehorn into the Hubble classification scheme. The paucity of barred spirals and of grand-design spirals at large redshifts is confirmed. It is concluded that the morphology of disk galaxies observed at look-back times smaller than 3--4 Gyr differs systematically from that of more distant galaxies viewed at look-back times of 4--8 Gyr. The disks of late-type spirals at z >0.5 are seen to be more chaotic than those of their nearer counterparts. Furthermore the spiral structure in distant early-type spirals appears to be less well-developed than it is in nearby early-galaxies.Comment: Accepted for publication in the A

    Cricket, migration and diasporic communities

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    Ever since different communities began processes of global migration, sport has been an integral feature in how we conceptualise and experience the notion of being part of a diaspora. Sport provides diasporic communities with a powerful means for creating transnational ties, but also shapes ideas of their ethnic and racial identities. In spite of this, theories of diaspora have been applied sparingly to sporting discourses. Due mainly to its central role in spreading dominant white racial narratives within the British Empire, and the various ways different ethnic groups have ‘played’ with the meanings and associations of the sport in the (post-)colonial period, cricket is an interesting focus for academic research. Despite W.G. Grace’s claim that cricket advances civilisation by promoting a common bond, binding together peoples of vastly different backgrounds, to this day cricket operates strict symbolic boundaries; defining those who do, and equally, do not belong. C.L.R. James’ now famous metaphor of looking ‘beyond the boundary’ captures the belief that, to fully understand the significance of cricket, and the sport’s roles in changing and shaping society, one must consider the wider social and political contexts within which the game is played. The collection of papers in this special issue does just that. Cricket acts as the point of departure in each, but the way in which ideas of power, representation and inequality are ‘played out’ is unique in each

    Reviewing research evidence and the case of participation in sport and physical recreation by black and minority ethnic communities

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    The paper addresses the implications of using the process of systematic review in the many areas of leisure where there is a dearth of material that would be admitted into conventional Cochrane Reviews. This raises important questions about what constitutes legitimate knowledge, questions that are of critical import not just to leisure scholars, but to the formulation of policy. The search for certainty in an area that lacks conceptual consensus results in an epistemological imperialism that takes a geocentric form. While clearly, there is a need for good research design whatever the style of research, we contend that the wholesale rejection of insightful research is profligate and foolhardy. A mechanism has to be found to capitalise on good quality research of whatever form. In that search, we draw upon our experience of conducting a review of the material available on participation in sport and physical recreation by people from Black and minority ethnic groups. The paper concludes with a proposal for a more productive review process that makes better use of the full panoply of good quality research available. © 2012 © 2012 Taylor & Francis

    To respond or not to respond - a personal perspective of intestinal tolerance

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    For many years, the intestine was one of the poor relations of the immunology world, being a realm inhabited mostly by specialists and those interested in unusual phenomena. However, this has changed dramatically in recent years with the realization of how important the microbiota is in shaping immune function throughout the body, and almost every major immunology institution now includes the intestine as an area of interest. One of the most important aspects of the intestinal immune system is how it discriminates carefully between harmless and harmful antigens, in particular, its ability to generate active tolerance to materials such as commensal bacteria and food proteins. This phenomenon has been recognized for more than 100 years, and it is essential for preventing inflammatory disease in the intestine, but its basis remains enigmatic. Here, I discuss the progress that has been made in understanding oral tolerance during my 40 years in the field and highlight the topics that will be the focus of future research

    Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

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    BACKGROUND. The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS. Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE. Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.NOAA Coral Reef Conservation Progra

    Preferential regulation of stably expressed genes in the human genome suggests a widespread expression buffering role of microRNAs

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    In this study, we comprehensively explored the stably expressed genes (SE genes) and fluctuant genes (FL genes) in the human genome by a meta-analysis of large scale microarray data. We found that these genes have distinct function distributions. miRNA targets are shown to be significantly enriched in SE genes by using propensity analysis of miRNA regulation, supporting the hypothesis that miRNAs can buffer whole genome expression fluctuation. The expression-buffering effect of miRNA is independent of the target site number within the 3'-untranslated region. In addition, we found that gene expression fluctuation is positively correlated with the number of transcription factor binding sites in the promoter region, which suggests that coordination between transcription factors and miRNAs leads to balanced responses to external perturbations

    Complete chloroplast genome sequence of Holoparasite Cistanche Deserticola (Orobanchaceae) reveals gene loss and horizontal gene transfer from Its host Haloxylon Ammodendron (Chenopodiaceae)

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    The central function of chloroplasts is to carry out photosynthesis, and its gene content and structure are highly conserved across land plants. Parasitic plants, which have reduced photosynthetic ability, suffer gene losses from the chloroplast (cp) genome accompanied by the relaxation of selective constraints. Compared with the rapid rise in the number of cp genome sequences of photosynthetic organisms, there are limited data sets from parasitic plants. The authors report the complete sequence of the cp genome of Cistanche deserticola, a holoparasitic desert species belonging to the family Orobanchaceae
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