5 resultados para planet

em Bucknell University Digital Commons - Pensilvania - USA


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Earth is the name of our planet and of an element from which we emerge. Pre-modern and non-modern traditions show us how to live at this conjunction better than many modern simulacra. This reflection examines in particular early medieval Christian tradition, set in dialogue with the emerging twenty-first-century field of ecosemiotics, while wandering from the Susquehanna Valley to Middle-earth.

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References to a “New North” have snowballed across popular media in the past 10 years. By invoking the phrase, scientists, policy analysts, journalists and others draw attention to the collision of global warming and global investment in the Arctic today and project a variety of futures for the region and the planet. While changes are apparent, the trope of a “New North” is not new. Discourses that appraised unfamiliar situations at the top of the world have recurred throughout the twentieth century. They have also accompanied attempts to cajole, conquer, civilize, consume, conserve and capitalize upon the far north. This article examines these politics of the “New North” by critically reading “New North” texts from the North American Arctic between 1910 and 2010. In each case, appeals to novelty drew from evaluations of the historical record and assessments of the Arctic’s shifting position in global affairs. “New North” authors pinpointed the ways science, state power, capital and technology transformed northern landscapes at different moments in time. They also licensed political and corporate influence in the region by delimiting the colonial legacies already apparent there. Given these tendencies, scholars need to approach the most recent iteration of the “New North” carefully without concealing or repeating the most troubling aspects of the Arctic’s past.

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Experimental modal analysis techniques are applied to characterize the planar dynamic behavior of two spur planetary gears. Rotational and translational vibrations of the sun gear, carrier, and planet gears are measured. Experimentally obtained natural frequencies, mode shapes, and dynamic response are compared to the results from lumped-parameter and finite element models. Two qualitatively different classes of mode shapes in distinct frequency ranges are observed in the experiments and confirmed by the lumped-parameter model, which considers the accessory shafts and fixtures in the system to capture all of the natural frequencies and modes. The finite element model estimates the high-frequency modes that have significant tooth mesh deflection without considering the shafts and fixtures. The lumped-parameter and finite element models accurately predict the natural frequencies and modal properties established by experimentation. Rotational, translational, and planet mode types presented in published mathematical studies are confirmed experimentally. The number and types of modes in the low-frequency and high-frequency bands depend on the degrees of freedom in the central members and planet gears, respectively. The accuracy of natural frequency prediction is improved when the planet bearings have differing stiffnesses in the tangential and radial directions, consistent with the bearing load direction. (C) 2012 Elsevier Ltd. All rights reserved.

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Like all organisms on the planet, honeybees (Apis mellifera) are susceptible to infection with a wide variety of viruses. These viruses may produce infections with no visible symptoms or may have devastating consequences on both the individual bee and the entire hive. Deformed Wing Virus, a member of the Iflavirus group of viruses, has an RNA genome and has had a particularly important impact on bee health. It can be spread between bees in a several ways – bees can infect each other during feeding or grooming activities, drones can pass the virus to the queen during mating and queens can lay infected eggs. The primary and most devastating way that these viruses are transmitted within and between hives involves a parasitic mite, an animal known ominously as Varroa destructor. The talk will discuss the effect that viruses have on the health and behavior of honeybees and will outline the collaborative research activities of Drs. Evans and Pizzorno over the last 7 years.

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For as far back as human history can be traced, mankind has questioned what it means to be human. One of the most common approaches throughout Western culture's intellectual tradition in attempts to answering this question has been to compare humans with or against other animals. I argue that it was not until Charles Darwin's publication of The Descent of Man and Selection in Relation to Sex (1871) that Western culture was forced to seriously consider human identity in relation to the human/ nonhuman primate line. Since no thinker prior to Charles Darwin had caused such an identity crisis in Western thought, this interdisciplinary analysis of the history of how the human/ nonhuman primate line has been understood focuses on the reciprocal relationship of popular culture and scientific representations from 1871 to the Human Genome Consortium in 2000. Focusing on the concept coined as the "Darwin-Müller debate," representations of the human/ nonhuman primate line are traced through themes of language, intelligence, and claims of variation throughout the popular texts: Descent of Man, The Jungle Books (1894), Tarzan of the Apes (1914), and Planet of the Apes (1963). Additional themes such as the nature versus nurture debate and other comparative phenotypic attributes commonly used for comparison between man and apes are also analyzed. Such popular culture representations are compared with related or influential scientific research during the respective time period of each text to shed light on the reciprocal nature of Western intellectual tradition, popular notions of the human/ nonhuman primate line, and the development of the field of primatology. Ultimately this thesis shows that the Darwin-Müller debate is indeterminable, and such a lack of resolution makes man uncomfortable. Man's unsettled response and desire for self-knowledge further facilitates a continued search for answers to human identity. As the Human Genome Project has led to the rise of new debates, and primate research has become less anthropocentric over time, the mysteries of man's future have become more concerning than the questions of our past. The human/ nonhuman primate line is reduced to a 1% difference, and new debates have begun to overshadow the Darwin-Müller debate. In conclusion, I argue that human identity is best represented through the metaphor of evolution: both have an unknown beginning, both have an indeterminable future with no definite end, and like a species under the influence of evolution, what it means to be human is a constant, indeterminable process of change.