25,748 research outputs found

    A Bayesian technique for improving the sensitivity of the atmospheric neutrino L/E analysis

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    This paper outlines a method for improving the precision of atmospheric neutrino oscillation measurements. One experimental signature for these oscillations is an observed deficit in the rate of νΟ\nu_{\mu} charged-current interactions with an oscillatory dependence on Lν/EνL_{\nu}/E_{\nu}, where LνL_{\nu} is the neutrino propagation distance, and EνE_{\nu} is the neutrino energy. For contained-vertex atmospheric neutrino interactions, the Lν/EνL_{\nu}/E_{\nu} resolution varies significantly from event to event. The precision of the oscillation measurement can be improved by incorporating information on Lν/EνL_{\nu}/E_{\nu} resolution into the oscillation analysis. In the analysis presented here, a Bayesian technique is used to estimate the Lν/EνL_{\nu}/E_{\nu} resolution of observed atmospheric neutrinos on an event-by-event basis. By separating the events into bins of Lν/EνL_{\nu}/E_{\nu} resolution in the oscillation analysis, a significant improvement in oscillation sensitivity can be achieved.Comment: 12 pages, 7 figures, submitted to Nucl. Instrum. Methods A, accompanies arXiv:1208.2915 [hep-ex

    Al-Kindi and Mu'tazila: Divine Attributes, Creation and Freedom

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    The paper discusses al-Kindi's response to doctrines held by contemporary theologians of the Mu‘tazilite school: divine attributes, creation, and freedom. In the first section it is argued that, despite his broadly negative theology, al-Kindi recognizes a special kind of “essential” positive attribute belonging to God. The second section argues that al-Kindi agreed with the Mu‘tazila in holding that something may not yet exist but still be an object of God's knowledge and power (as the Mu‘tazila put it, that “non-being” is a “thing”). Also it presents a new parallel between al-Kindi and John Philoponus. The third section gives an interpretation of al-Kindi as a compatibilist, in other words as holding that humans may be free even though their actions are necessitated. In all three cases, it is argued, al-Kindi is close to the Mu‘tazilite point of view, though he departs from them in the arguments he gives for that point of view

    Vision, Light and Color in al-Kindi, Ptolemy and the Ancient Commentators

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    Al-Kindi was influenced by two Greek traditions in his attempts to explain vision, light and color. Most obviously, his works on optics are indebted to Euclid and, perhaps indirectly, to Ptolemy. But he also knew some works from the Aristotelian tradition that touch on the nature of color and vision. Al-Kindi explicitly rejects the Aristotelian account of vision in his De Aspectibus, and adopts a theory according to which we see by means of a visual ray emitted from the eye. But in the same work, al-Kindi draws on Philoponus’ commentary on Aristotle's De Anima. His borrowing from this commentary, via an Arabic paraphrase of the De Anima, was crucial in the development of al-Kindi's new "punctiform analysis of light." Conversely, two broadly Aristotelian works by al-Kindi, which explain the reason things are colored, engage with problems about color dealt with in the Aristotelian tradition (e.g. by Alexander of Aphrodisias ). But here the Aristotelian theory, and in particular the Aristotelian notion of the transparent, is abandoned in order to accommodate the visual ray theory expounded in De Aspectibus

    The Arabic Sea Battle: al-Fārābč on the Problem of Future Contingents

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    Ancient commentators like Ammonius and Boethius tried to solve Aristotle's “sea battle argument” in On Interpretation 9 by saying that statements about future contingents are “indefinitely” true or false. They were followed by al-Fārābī in his commentary on On Interpretation. The article sets out two possible interpretations of what “indefinitely” means here, and shows that al-Fārābī actually has both conceptions: one applied in his interpretation of Aristotle, and another that he is forced into by the problem of divine foreknowledge. It also explains the relevance of al-Fārābī's remarks as a link between the non-statistical modal theories of Philo and Avicenna

    Preparing for the House of God: Nepali Muslim Narratives of the Hajj

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    This essay focuses on first-person narratives from Nepali Muslims directly before and after their journeys from Kathmandu to Mecca, for the Hajj pilgrimage, in 2005-2006, collected and translated by the author. To date, studies and public representations of Muslims in Nepal in the period of Nepal’s long transition to secularism have focused predominantly on the population’s mobilization of religious identity and its religio-political aspirations, productions, and experiences that help to constitute it as a collective. These representations have been key in affirming Muslims’ rights as a minority in a newly secular federal republic of immense ethnic and religious diversity and a history of Hindu hegemony. Through the Hajj narratives of Nepali Muslim presented in this chapter, a contrasting portrait to these dominant representations is offered. This portrait offers a view into the interior religious worlds of Muslims in Nepal during this period. In them we get a glimpse of the every-day ness of their religious endeavors and the interior dimensions of piety that pilgrimage can cultivate, including a notion of collectivity that is based in faith and practice

    Evolution of female choice and age-dependent male traits with paternal germ-line mutation

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    Several studies question the adaptive value of female preferences for older males. Theory and evidence show that older males carry more deleterious mutations in their sperm than younger males carry. These mutations are not visible to females choosing mates. Germ-line mutations could oppose preferences for "good genes." Choosy females run the risk that offspring of older males will be no more attractive or healthy than offspring of younger males. Germ-line mutations could pose a particular problem when females can only judge male trait size, rather than assessing age directly. I ask whether or not females will prefer extreme traits, despite reduced offspring survival due to age-dependent mutation. I use a quantitative genetic model to examine the evolution of female preferences, an age-dependent male trait, and overall health ("condition"). My dynamical equation includes mutation bias that depends on the generation time of the population. I focus on the case where females form preferences for older males because male trait size depends on male age. My findings agree with good genes theory. Females at equilibrium always select above-average males. The trait size preferred by females directly correlates with the direct costs of the preference. Direct costs can accentuate the equilibrium preference at a higher rate than mutational parameters. Females can always offset direct costs by mating with older, more ornamented males. Age-dependent mutation in condition maintains genetic variation in condition and thereby maintains the selective value of female preferences. Rather than eliminating female preferences, germ-line mutations provide an essential ingredient in sexual selection.Comment: 10 pages, 5 figure

    Gas turbine engine with recirculating bleed

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    Carbon monoxide and unburned hydrocarbon emissions in a gas turbine engine are reduced by bleeding hot air from the engine cycle and introducing it back into the engine upstream of the bleed location and upstream of the combustor inlet. As this hot inlet air is recycled, the combustor inlet temperature rises rapidly at a constant engine thrust level. In most combustors, this will reduce carbon monoxide and unburned hydrocarbon emissions significantly. The preferred locations for hot air extraction are at the compressor discharge or from within the turbine, whereas the preferred reentry location is at the compressor inlet

    The National Muslim Forum Nepal: Experiences of Conflict, Formations of Identity

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    With Nepal\u27s recent transition to state secularism, the politicization of Muslim religious identity has emerged with increasing vitality. One particular pan-Nepali Muslim organization, the Rastriya Muslim Mane Nepal (National Muslim Forum Nepal), offers a window into the complex relationship between national and religious identity that animates this politicization. Through analysis of the National Muslim Forum\u27s earliest discourses, produced between 2005 and 2006, both immediately before and after the people\u27s revolution that resulted in the declaration of Nepal as a secular state, this essay highlights the ways that experiences of conflict coupled with a national political transition shape and contribute to this politicization. It also offers a picture of some of the ways in which conceptions of the nation and religious community come together to help define the forum\u27s call for a new Muslim religio-political identity across a diverse Nepali national population. [excerpt

    Earned Income Tax Credit: Path Dependence and the Blessing of Undertheorization

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    Some commentators have lamented that the Earned Income Tax Credit (EITC) is undertheorized—that its purpose is unclear—and that its design is therefore suboptimal. This Note explores the credit’s path-dependent past, which has resulted in a present-day EITC that manifests a diverse, uncoordinated assortment of policy purposes. Although the EITC’s ambiguity of purpose may yield policy inefficiencies, this Note argues that it also produces significant political benefits that would-be reformers who value the EITC’s many societal benefits should take into account before they attempt to enact any major overhaul
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