1,243 research outputs found

    New Technologies for Space Avionics, 1993

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    The report reviews a 1993 effort that investigated issues associated with the development of requirements, with the practice of concurrent engineering and with rapid prototyping, in the development of a next-generation Reaction Jet Drive Controller. This report details lessons learned, the current status of the prototype, and suggestions for future work. The report concludes with a discussion of the vision of future avionics architectures based on the principles associated with open architectures and integrated vehicle health management

    Citizens without nations

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    To broach the question of whether citizenship could exist without (or beyond) community, this paper discusses genealogies of citizenship as membership that binds an individual to the community of birth (of the self or a parent). It is birthright as fraternity that blurs the boundary between citizenship and nationality. After briefly discussing recent critical studies on birthright citizenship (whether it is civic or ethnic or blood or soil) by Ayelet Shachar and Jacqueline Stevens, the paper discusses three critical genealogies of the relationship between birthright and citizenship by Max Weber, Hannah Arendt, and Michel Foucault. Although each provides a critical perspective into the question, Weber reduces citizenship to fraternity with nation and Arendt reduces citizenship to fraternity with the state. It is Foucault who illustrates racialization of fraternity as the connection between citizenship and nationality. Yet, since Foucault limits his genealogical investigations to the 18th and 19th centuries, a genealogy of fraternity of what he calls an immense biblical and Greek tradition remains for Derrida to articulate as a question of citizenship

    Humpback whales interfering when mammal-eating killer whales attack other species: mobbing behavior and interspecific altruism?

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    Humpback whales (Megaptera novaeangliae) are known to interfere with attacking killer whales (Orcinus orca). To investigate why, we reviewed accounts of 115 interactions between them. Humpbacks initiated the majority of interactions (57% vs. 43%; n=72), although the killer whales were almost exclusively mammal-eating forms (MEKWs, 95%) vs. fish-eaters (5%; n=108). When MEKWs approached humpbacks (n=27), they attacked 85% of the time and targeted only calves. When humpbacks approached killer whales (n=41), 93% were MEKWs, and >87% of them were attacking or feeding on prey at the time. When humpbacks interacted with attacking MEKWs, 11% of the prey were humpbacks and 89% comprised 10 other species, including 3 cetaceans, 6 pinnipeds, and 1 teleost fish. Approaching humpbacks often harassed attacking MEKWs (>55% of 56 interactions), regardless of the prey species, which we argue was mobbing behavior. Humpback mobbing sometimes allowed MEKW prey, including nonhumpbacks, to escape. We suggest that humpbacks initially responded to vocalizations of attacking MEKWs without knowing the prey species targeted. Although reciprocity or kin selection might explain communal defense of conspecific calves, there was no apparent benefit to humpbacks continuing to interfere when other species were being attacked. Interspecific altruism, even if unintentional, could not be ruled out

    Killer whales and marine mammal trends in the North Pacific : a re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis

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    This paper is not subject to U.S. copyright. The definitive version was published in Marine Mammal Science 23 (2007): 766–802, doi:10.1111/j.1748-7692.2006.00093.x.Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50–100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem

    nnResting state fMRI scanner instabilities revealed by longitud inal phantom scans in a multi-center study

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    Quality assurance (QA) is crucial in longitudinal and/or multi-site studies, which involve the collection of data from a group of subjects over time and/or at different locations. It is important to regularly monitor the performance of the scanners over time and at different locations to detect and control for intrinsic differences (e.g., due to manufacturers) and changes in scanner performance (e.g., due to gradual component aging, software and/or hardware upgrades, etc.). As part of the Ontario Neurodegenerative Disease Research Initiative (ONDRI) and the Canadian Biomarker Integration Network in Depression (CAN-BIND), QA phantom scans were conducted approximately monthly for three to four years at 13 sites across Canada with 3T research MRI scanners. QA parameters were calculated for each scan using the functional Biomarker Imaging Research Network\u27s (fBIRN) QA phantom and pipeline to capture between- and within-scanner variability. We also describe a QA protocol to measure the full-width-at-half-maximum (FWHM) of slice-wise point spread functions (PSF), used in conjunction with the fBIRN QA parameters. Variations in image resolution measured by the FWHM are a primary source of variance over time for many sites, as well as between sites and between manufacturers. We also identify an unexpected range of instabilities affecting individual slices in a number of scanners, which may amount to a substantial contribution of unexplained signal variance to their data. Finally, we identify a preliminary preprocessing approach to reduce this variance and/or alleviate the slice anomalies, and in a small human data set show that this change in preprocessing can have a significant impact on seed-based connectivity measurements for some individual subjects. We expect that other fMRI centres will find this approach to identifying and controlling scanner instabilities useful in similar studies

    Multiculturalism and moderate secularism

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    What is sometimes talked about as the ‘post-secular’ or a ‘crisis of secularism’ is, in Western Europe, quite crucially to do with the reality of multiculturalism. By which I mean not just the fact of new ethno-religious diversity but the presence of a multiculturalist approach to this diversity, namely: the idea that equality must be extended from uniformity of treatment to include respect for difference; recognition of public/private interdependence rather than dichotomized as in classical liberalism; the public recognition and institutional accommodation of minorities; the reversal of marginalisation and a remaking of national citizenship so that all can have a sense of belonging to it. I think that equality requires that this ethno-cultural multiculturalism should be extended to include state-religion connexions in Western Europe, which I characterise as ‘moderate secularism’, based on the idea that political authority should not be subordinated to religious authority yet religion can be a public good which the state should assist in realising or utilising. I discuss here three multiculturalist approaches that contend this multiculturalising of moderate secularism is not the way forward. One excludes religious groups and secularism from the scope of multiculturalism (Kymlicka); another largely limits itself to opposing the ‘othering’ of groups such as Jews and Muslims (Jansen); and the third argues that moderate secularism is the problem not the solution (Bhargava)

    Socio-demographic factors associated with pet ownership amongst adolescents from a UK birth cohort

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    Background: In developed nations, pet ownership is common within families. Both physical and psychological health benefits may result from owning a pet during childhood and adolescence. However, it is difficult to determine whether these benefits are due to pet ownership directly or to factors linked to both pet ownership and health. Previous research found associations between a range of socio-demographic factors and pet ownership in seven-year-old children from a UK cohort. The current study extends this research to adolescence, considering that these factors may be important to consider in future Human-Animal Interaction (HAI) research across childhood.Results:The Avon Longitudinal Study of Parents and Children (ALSPAC) collected pet ownership data prospectively via maternal reports from gestation up to age 10 years old and via self-report retrospectively at age 18 for ages 11(n= 3063) to 18 years old (n= 3098) on cats, dogs, rabbits, rodents, birds, fish, tortoise/turtles and horses. The dataset also contains a wide range of potential confounders, including demographic and socio-economic variables.The ownership of all pet types peaked at age 11 (80%) and then decreased during adolescence, with the exclusion of cats which remained constant (around 30%), and dogs which increased through 11–18 years (26–37%). Logistic regression was used to build multivariable models for ownership of each pet type at age 13 years, and the factors identified in these models were compared to previously published data for 7 year-olds in the same cohort. There was some consistency with predictors reported at age 7. Generally sex, birth order, maternal age, maternal education, number of people in the household, house type, and concurrent ownership of other pets were associated with pet ownership at both 7 and 13 years (the direction of association varied according to pet type).Factors that were no longer associated with adolescent pet ownership included child ethnicity, paternal education,and parental social class.Conclusions:A number of socio-demographic factors are associated with pet ownership in childhood and adolescence and they differ according to the type of pet, and age of child. These factors are potential confounders that must be considered in future HAI studies
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