5,469 research outputs found

    Risk Factors for Severe Inter-Sibling Violence: A Preliminary Study of a Youth Forensic Sample

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    The perpetration of severe inter-sibling violence (SISV) remains a largely unexplored area of family violence. This article describes an investigation of risk factors for intentional SISV perpetration. A sample of 111 young people under the care of the Scottish criminal justice or welfare systems was studied. A SISV perpetration interview schedule was developed to measure the influence of 43 potential predictor variables. The Buss and Perry Aggression Questionnaire and Levenson's Self-Report Psychopathy Scale were also employed in this exploratory analysis

    A molecular dynamics study of the thermal properties of thorium oxide

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    There is growing interest in the exploitation of the thorium nuclear fuel cycle as an alternative to that of uranium. As part of a wider study of the suitability of thorium dioxide (thoria) as a nuclear fuel, we have used molecular dynamics to investigate the thermal expansion, oxygen diffusion, and heat capacity of pure thoria and uranium doped (1-10%) thoria between 1500K and 3600 K. Our results indicate that the thermal performance of the thoria matrix, even when doped with 10%U, is comparable to, and possibly better than, that of UO2

    Theoretical investigation of the scope of sequential ligand tuning using a bifunctional scorpionate tris(1,2,4-triazolyl)borate-based architecture

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    The donor properties of a series of tripodal mixed N-donor/carbene ligands derived through sequential alkylation of hydrotris(1,2,4-triazolyl)borate have been investigated by density functional theory (DFT) methods. The structures of complexes of the form [Mo(L)(CO)3]- were optimized (L = [HB(1,2,4-triazolyl)n(1,2,4-triazol-5-ylidene)3-n]- (n = 0 – 3), hydrotris(pyrazolyl)borate, hydrotris(3,5-dimethylpyrazolyl)borate and hydrotris(imidazol-2-ylidene)borate) and nuCO frequencies for these complexes and partial charges of their Mo(CO)3 fragments were determined. Results show that ligand donation is highly tunable when compared to similar experimentally known ligands with a shift in the symmetric nuCO stretching mode of -39 cm -1 on going from the tris(1,2,4-triazolyl)borate complexes to that of the triscarbene hydrotris(1,2,4-triazol-5-ylidene) and an increase in partial charge (distributed multipole analysis) of the Mo(CO)3 fragment from -0.23 to -0.48

    A Discrete X-Ray Transform for Chromotomographic Hyperspectral Imaging

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    The United States Air Force has a pressing need for new methods of hyperspectral imaging. All current hyperspectral imaging technologies require long exposure times, since each involves filtering the available light, either spatially or according to color. We consider a recently proposed method for hypserspectral imaging that promises shorter exposure times. This new method applies the mathematical principles of tomography to the hyperspectral data cube. Known as chromotomography, this method uses a spinning prism to essentially capture the integrals of this cube over many rotations of a single line. This thesis addresses some of the mathematical issues that arise when trying to reconstruct a hyperspectral image from chromotomographic measurements. After reviewing some of the mathematical shortcomings of the current state of the art--which arise from the technical difficulties of working with the continuous-variable X-ray transform--we make three contributions. First, we introduce a mathematically rigorous, discrete, X-ray transform that is somewhat faithful to its continuous cousin. Second, we show how under a few simplifying assumptions, our discrete transform can be generalized so as to provide a good approximation of the continuous one. This discretization allows us to apply modern finite-dimensional optimization methods to the chromotomographic reconstruction problem. Our third contribution is to apply a popular new example of such a method, known as Split Bregman iteratio

    Factors Influencing Largemouth Bass Recruitment: Implications for the Illinois Management and Stocking Program

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    Annual Progress Report issued August 2002; NOTE: Two different reports numbered 02/06 were issued from the CAE.Report issued on: August 2002INHS Technical Report prepared for Division of Fisheries Illinois Department of Natural Resource

    The Massachusetts Environmental Industry: Facing the Challenges of Maturity

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    For most of the past 20 years, the environmental industry has been a very significant one, both in Massachusetts and across the country. Some have placed it alongside the electronics, computer hardware, software, biotechnology, fiber optics, and composite materials industries as part of the high-technology sector that has diversified and strengthened the state’s economy. Nationally, environmental industry employment exceeded that of several major manufacturing industries, including chemicals, paper, and aerospace. In the late 1990s, however, the momentum of the environmental movement began to wane. A decline in both employment and sales suggests that many of the most pressing environmental concerns have been addressed, first by government regulations, then by companies’ in-house pollution-reduction efforts. Industry executives are aware of certain steps that can be taken to keep Massachusetts moving forward in the environmental industry. Still, they have concerns about future growth

    Evaluating the use of lecture capture using a revealed preference approach

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    This article discusses the introduction of lecture capture technology on a large undergraduate module with diverse student cohorts. Literature has so far relied on surveying students to discover their use of the technology or attempted to quantify the impact of watching lecture recordings on assessment performance. Alternatively, the principal contribution of this article is an evaluation of the use of the recorded lectures using a revealed preference approach. Specifically we identify to what extent students watched lecture recordings, rather than simply claimed to watch them when asked to provide comments on the technology. Data indicates the number of distinct students who watched recordings, the frequency with which they watched recordings, the average length of viewings as well as the time of day when lectures were viewed. We monitored viewings over two academic years, identifying ‘spikes’ in the number of viewings in the days before tests, as well as regularities in the viewing patterns across the two years. We analyse the data to assess the extent to which students used the recordings, how and when they watched the recordings. We conclude that the students value lecture recordings, making more extensive use of the recordings than has been identified in the literature to date. Ultimately, lecture recordings are suggested to offer valuable support for students’ independent study

    A Gravitational Theory of the Quantum

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    The synthesis of quantum and gravitational physics is sought through a finite, realistic, locally causal theory where gravity plays a vital role not only during decoherent measurement but also during non-decoherent unitary evolution. Invariant set theory is built on geometric properties of a compact fractal-like subset IUI_U of cosmological state space on which the universe is assumed to evolve and from which the laws of physics are assumed to derive. Consistent with the primacy of IUI_U, a non-Euclidean (and hence non-classical) state-space metric gpg_p is defined, related to the pp-adic metric of number theory where pp is a large but finite Pythagorean prime. Uncertain states on IUI_U are described using complex Hilbert states, but only if their squared amplitudes are rational and corresponding complex phase angles are rational multiples of 2π2 \pi. Such Hilbert states are necessarily gpg_p-distant from states with either irrational squared amplitudes or irrational phase angles. The gappy fractal nature of IUI_U accounts for quantum complementarity and is characterised numerically by a generic number-theoretic incommensurateness between rational angles and rational cosines of angles. The Bell inequality, whose violation would be inconsistent with local realism, is shown to be gpg_p-distant from all forms of the inequality that are violated in any finite-precision experiment. The delayed-choice paradox is resolved through the computational irreducibility of IUI_U. The Schr\"odinger and Dirac equations describe evolution on IUI_U in the singular limit at p=∞p=\infty. By contrast, an extension of the Einstein field equations on IUI_U is proposed which reduces smoothly to general relativity as p→∞p \rightarrow \infty. Novel proposals for the dark universe and the elimination of classical space-time singularities are given and experimental implications outlined

    Elevating crop disease resistance with cloned genes

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    Essentially all plant species exhibit heritable genetic variation for resistance to a variety of plant diseases caused by fungi, bacteria, oomycetes or viruses. Disease losses in crop monocultures are already significant, and would be greater but for applications of disease-controlling agrichemicals. For sustainable intensification of crop production, we argue that disease control should as far as possible be achieved using genetics rather than using costly recurrent chemical sprays. The latter imply CO2 emissions from diesel fuel and potential soil compaction from tractor journeys. Great progress has been made in the past 25 years in our understanding of the molecular basis of plant disease resistance mechanisms, and of how pathogens circumvent them. These insights can inform more sophisticated approaches to elevating disease resistance in crops that help us tip the evolutionary balance in favour of the crop and away from the pathogen. We illustrate this theme with an account of a genetically modified (GM) blight-resistant potato trial in Norwich, using the Rpi-vnt1.1 gene isolated from a wild relative of potato, Solanum venturii, and introduced by GM methods into the potato variety Desiree

    Quantifying tumour-infiltrating lymphocyte subsets : a practical immuno-histochemical method

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    Background: Efficient histological quantification of tumour-infiltrating T and B lymphocyte (TIL) subsets in archival tissues would greatly facilitate investigations of the role of TIL in human cancer biology. We sought to develop such a method. Methods: Ten ×40 digital images of 4 ÎŒ sections of 16 ductal invasive breast carcinomas immunostained for CD3, CD4, CD8, and CD20 were acquired (a total of 640 images). The number of pixels in each image matching a partition of Lab colour space corresponding to immunostained cells were counted using the ‘Color range’ and ‘Histogram’ tools in Adobe Photoshop 7. These pixel counts were converted to cell counts per mm2 using a calibration factor derived from one, two, three or all 10 images of each case/antibody combination. Results: Variations in the number of labelled pixels per immunostained cell made individual calibration for each case/antibody combination necessary. Calibration based on two fields containing the most labelled pixels gave a cell count minimally higher (+ 5.3%) than the count based on 10-field calibration, with 95% confidence limits − 14.7 to + 25.3%. As TIL density could vary up to 100-fold between cases, this accuracy and precision are acceptable. Conclusion: The methodology described offers sufficient accuracy, precision and efficiency to quantify the density of TIL sub-populations in breast cancer using commonly available software, and could be adapted to batch processing of image files
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