1,221 research outputs found

    General relativistic spinning fluids with a modified projection tensor

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    An energy-momentum tensor for general relativistic spinning fluids compatible with Tulczyjew-type supplementary condition is derived from the variation of a general Lagrangian with unspecified explicit form. This tensor is the sum of a term containing the Belinfante-Rosenfeld tensor and a modified perfect-fluid energy-momentum tensor in which the four-velocity is replaced by a unit four-vector in the direction of fluid momentum. The equations of motion are obtained and it is shown that they admit a Friedmann-Robertson-Walker space-time as a solution.Comment: Submitted to General Relativity and Gravitatio

    The Role of Functional Skills Instruction

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    Functional skills, according to Cronin (1996), are the tasks that help individuals become successful and independent adults. Vandercook (1991) stated, “a true functional skill is one that is initiated, used, and maintained under typical circumstances” (p. 320). Functional skills are often taught in conjunction with functional academics. Bouck and Joshi (2012) defined functional academics as an approach to teach “students the skills to help them be productive members of society and support post school outcomes” (p. 140). Functional academics may include “core subject content, vocational education, community access, daily living, personal finance, independent living, transportation, social skills and relationships, and selfdetermination” (Bouck & Joshi, 2012, p. 140). This article will discuss functional academics as it relates to successful transitions into adulthood through literacy, social skills, selfdetermination, and community involvement instruction

    Architectural speculations on the Library of the Future

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    Poster presentationThis poster details work from a graduating design studio for Masters students of architecture at the University of Adelaide, and its engagement with the university’s central library, the Barr Smith Library, concurrently undertaking its own major review. The central task of the studio was to grapple with the question of the library of the future. It sought ways of reinventing the library, an institution and a social and architectural typology that is seriously threatened by technological and social changes, chief among them being digitalisation and privatisation. In response to this situation, the studio asked its participants: what new hybrid configurations, scenarios, programs, and typologies are plausible to sustaining the promise of the library? Details of the premise and design process, six individual proposals, and discussion of the outcomes of the studio are included in the poster, which incorporates numerous visual analyses, design diagrams, and renderings to illustrate the discussion.Julian Worrall, Judy Baile

    Motif Discovery through Predictive Modeling of Gene Regulation

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    We present MEDUSA, an integrative method for learning motif models of transcription factor binding sites by incorporating promoter sequence and gene expression data. We use a modern large-margin machine learning approach, based on boosting, to enable feature selection from the high-dimensional search space of candidate binding sequences while avoiding overfitting. At each iteration of the algorithm, MEDUSA builds a motif model whose presence in the promoter region of a gene, coupled with activity of a regulator in an experiment, is predictive of differential expression. In this way, we learn motifs that are functional and predictive of regulatory response rather than motifs that are simply overrepresented in promoter sequences. Moreover, MEDUSA produces a model of the transcriptional control logic that can predict the expression of any gene in the organism, given the sequence of the promoter region of the target gene and the expression state of a set of known or putative transcription factors and signaling molecules. Each motif model is either a kk-length sequence, a dimer, or a PSSM that is built by agglomerative probabilistic clustering of sequences with similar boosting loss. By applying MEDUSA to a set of environmental stress response expression data in yeast, we learn motifs whose ability to predict differential expression of target genes outperforms motifs from the TRANSFAC dataset and from a previously published candidate set of PSSMs. We also show that MEDUSA retrieves many experimentally confirmed binding sites associated with environmental stress response from the literature.Comment: RECOMB 200

    Monkey-based Research on Human Disease: The Implications of Genetic Differences

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    Assertions that the use of monkeys to investigate human diseases is valid scientifically are frequently based on a reported 90–93% genetic similarity between the species. Critical analyses of the relevance of monkey studies to human biology, however, indicate that this genetic similarity does not result in sufficient physiological similarity for monkeys to constitute good models for research, and that monkey data do not translate well to progress in clinical practice for humans. Salient examples include the failure of new drugs in clinical trials, the highly different infectivity and pathology of SIV/HIV, and poor extrapolation of research on Alzheimer’s disease, Parkinson’s disease and stroke. The major molecular differences underlying these inter-species phenotypic disparities have been revealed by comparative genomics and molecular biology — there are key differences in all aspects of gene expression and protein function, from chromosome and chromatin structure to post-translational modification. The collective effects of these differences are striking, extensive and widespread, and they show that the superficial similarity between human and monkey genetic sequences is of little benefit for biomedical research. The extrapolation of biomedical data from monkeys to humans is therefore highly unreliable, and the use of monkeys must be considered of questionable value, particularly given the breadth and potential of alternative methods of enquiry that are currently available to scientists

    A Derivation of Three-Dimensional Inertial Transformations

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    The derivation of the transformations between inertial frames made by Mansouri and Sexl is generalised to three dimensions for an arbitrary direction of the velocity. Assuming lenght contraction and time dilation to have their relativistic values, a set of transformations kinematically equivalent to special relativity is obtained. The ``clock hypothesis'' allows the derivation to be extended to accelerated systems. A theory of inertial transformations maintaining an absolute simultaneity is shown to be the only one logically consistent with accelerated movements. Algebraic properties of these transformations are discussed. Keywords: special relativity, synchronization, one-way velocity of light, ether, clock hypothesis.Comment: 16 pages (A5), Latex, one figure, to be published in Found. Phys. Lett. (1997
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