2,157 research outputs found

    A Cache Coherence Protocol for Concurrency Control and Recovery in Distributed Object-orientated Systems

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    Submitted to the University of London for the Degree of Doctor of Philosophy in Computer Scienc

    A Study on the Growth and Formation of Single Person Households and Their Housing Decisions in Taiwan

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    The number of single person households has dramatically increased in Taiwan in the past several decades as it has elsewhere in the world, but this phenomenon has been largely neglected in the literature. This research explores the factors that affect the formation of single person households and their housing decisions. Taiwan¡¦s population census data for 1980, 1990 and 2000 are used. Some interesting trends can be found. First of all, people who are married or cohabiting have exhibited an increasing tendency to live alone census by census. This shows the increasing need in a modern society for the husband and wife to live separately due to employment or other reasons. Secondly, unmarried and widowed elderly persons have had an increasing probability of living alone over the decades. Thirdly, the number of female single person households has been increasing rapidly, and there is a higher probability that they are homeowners and also occupying a larger living space than their male counterparts. To sum up, the results of this study show that the demand for housing among single person households will continue to increase as their numbers increase. Their demand for homeownership and living space are also increasing.Single person household formation; Tenure choice; Living space; Binary probit model; Sample selection model

    Solutions of Schr\"odinger equations\\ with symmetry in orientation preserving tetrahedral group

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    We consider the nonlinear Schr\"odinger equation \begin{equation*} \Delta u = \big( 1 +\ve V_1(|y|)\big)u - |u|^{p-1}u \quad \text{in} \quad \mathbb{R}^N, \quad N\ge 3, \quad p \in \left(1, \frac{N+2}{N-2}\right).\end{equation*} The phenomenon of pattern formation has been a central theme in the study of nonlinear Schr\"odinger equations. However, the following nonexistence of O(N)O(N) symmetry breaking solution is well-known: if the potential function is radial and radially nondecreasing, any positive solution must be radial. Therefore, solutions of interesting patterns, such as those with symmetry in a discrete subgroup of O(N)O(N), can only exist after violating the assumptions. For a potential function that is radial but asymptotically decreasing, a solution with symmetry merely in a discrete subgroup of O(2)O(2) has been presented. These observations pose the question of whether patterns of higher dimensions can appear. In this study, the existence of nonradial solutions whose symmetry group is a discrete subgroup of O(3)O(3), more precisely, the orientation-preserving regular tetrahedral group is shown

    Gender-related Factors Associated with Upper Extremity Function in Workers

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    Objectives: This study aimed to find gender distinctions in terms of the sociology of the population; to determine work-related factors; to analyze gender differences in daily living, work, sports, and art performances; and to identify gender-related factors that limited performance of daily living and work activities.Methods: A questionnaire was designed that included disabilities of the arm, shoulder, and hand (DASH), accident history, disease history, work duration at current workplace, marital status, job satisfaction, job autonomy, and physical demands of the job. Out of 1,853 workers surveyed, 1,173 questionnaires (63.3%; 987 males, 186 females) included responses to DASH disability and DASH optional work and were judged acceptable for analysis.Results: Upper extremity functional limitation during work and daily living was higher for females than males. The limitations for males increased according to their household work time, accident history, work duration, job satisfaction, physical demand, and job autonomy. Meanwhile, female workers' upper extremity discomfort was influenced by their disease history, job satisfaction, and physical demands. In addition, the size of the company affected male workers’ upper extremity function, while marriage and hobbies influenced that of female workers.Conclusion: This study addressed sociodemographic factors and work-related factors that affect each gender’s upper extremity function during daily living and working activities. Each factor had a different influence. Further studies are needed to identify the effect that role changes, not being influenced by risks at work, have on musculoskeletal disorders

    Eurotatorian paraphyly: Revisiting phylogenetic relationships based on the complete mitochondrial genome sequence of Rotaria rotatoria (Bdelloidea: Rotifera: Syndermata)

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    <p>Abstract</p> <p>Background</p> <p>The Syndermata (Rotifera+Acanthocephala) is one of the best model systems for studying the evolutionary origins and persistence of different life styles because it contains a series of lineage-specific life histories: Monogononta (cyclic parthenogenetic and free-living), Bdelloidea (entirely parthenogenetic and mostly benthic dweller), Seisonidea (exclusively bisexual and epizoic or ectoparasitic), and Acanthocephala (sexual and obligatory endoparasitic). Providing phylogenetic resolution to the question of Eurotatoria (Monogononta and Bdelloidea) monophyly versus paraphyly is a key factor for better understanding the evolution of different life styles, yet this matter is not clearly resolved. In this study, we revisited this issue based on comparative analysis of complete mitochondrial genome information for major groups of the Syndermata.</p> <p>Results</p> <p>We determined the first complete mitochondrial genome sequences (15,319 bp) of a bdelloid rotifer, <it>Rotaria rotatoria</it>. In order to examine the validity of Eurotatoria (Monogononta and Bdelloidea) monophyly/paraphyly, we performed phylogenetic analysis of amino acid sequences for eleven protein-coding genes sampled from a wide variety of bilaterian representatives. The resulting mitochondrial genome trees, inferred using different algorithms, consistently failed to recover Monogononta and Bdelloidea as monophyletic, but instead identified them as a paraphyletic assemblage. Bdelloidea (as represented by <it>R. rotatoria</it>) shares most common ancestry with Acanthocephala (as represented by <it>L. thecatus</it>) rather than with monogonont <it>B. plicatilis</it>, the other representative of Eurotatoria.</p> <p>Conclusion</p> <p>Comparisons of inferred amino acid sequence and gene arrangement patterns with those of other metazoan mtDNAs (including those of acanthocephalan <it>L. thecatus </it>and monogonont <it>B. plicatilis</it>) support the hypothesis that Bdelloidea shares most common ancestry with Acanthocephala rather than with Monogononta. From this finding, we suggest that the obligatory asexuality of bdelloideans may have secondarily derived from some other preexisting condition in earlier lineage of rotifers. Providing a more complete assessment of phylogenetic relationships and inferring patterns of evolution of different types of life styles among Syndermata awaits comparisons requiring mitochondrial genome sequencing of Seisonidea.</p

    Relative entropy technique in terms of position and momentum and its application to Euler-Poisson system

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    This paper presents a systematic study of the relative entropy technique for compressible motions of continuum bodies described as Hamiltonian flows. While the description for the classical mechanics of NN particles involves a Hamiltonian in terms of position and momentum vectors, that for the continuum fluid involves a Hamiltonian in terms of density and momentum. For space dimension d≥2d\ge 2, the Hamiltonian functional has a non-convex dependency on the deformation gradient or placement map due to material frame indifference. Because of this, the applicability of the relative entropy technique with respect to the deformation gradient or the placement map is inherently limited. Despite these limitations, we delineate the feasible applications and limitations of the technique by pushing it to its available extent. Specifically, we derive the relative Hamiltonian identity, where the Hamiltonian takes the position and momentum field as its primary and conjugate state variables, all within the context of the referential coordinate system that describes the motion. This approach, when applicable, turns out to yield rather strong stability statements. As instances, we consider Euler-Poisson systems in one space dimension. For a specific pressureless model, we verify non-increasing L2L^2 state differences before the formation of δ\delta-shock. In addition, weak-strong uniqueness, stability of rarefaction waves, and convergence to the gradient flow in the singular limit of large friction are shown. Depending on the presence or absence of pressure, assumptions are made to suitably accommodate phenomena such as δ\delta-shocks, vacuums, and shock discontinuities in the weak solutions.Comment: 35 page

    The effect of multileaf collimator leaf width on the radiosurgery planning for spine lesion treatment in terms of the modulated techniques and target complexity

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    PURPOSE: We aim to evaluate the effects of multileaf collimator (MLC) leaf width (5 mm vs. 2.5 mm) on the radiosurgery planning for the treatment of spine lesions according to the modulated techniques (intensity-modulated radiotherapy [IMRT] vs. volumetric-modulated arc therapy [VMAT]) and the complexity of the target shape. METHODS: For this study, artificial spinal lesions were contoured and used for treatment plans. Three spinal levels (C5, T5, and L2 spines) were selected, and four types of target shapes reflecting the complexity of lesions were contoured. The treatment plans were performed using 2.5-mm and 5-mm MLCs, and also using both static IMRT and VMAT. In total, 48 treatment plans were established. The efficacy of each treatment plan was compared using target volume coverage (TVC), conformity index (CI), dose gradient index (GI), and V(30%). RESULTS: When the 5-mm MLC was replaced by the 2.5-mm MLC, TVC and GI improved significantly by 5.68% and 6.25%, respectively, while CI did not improve. With a smaller MLC leaf width, the improvement ratios of the TVC were larger in IMRT than VMAT (8.38% vs. 2.97%). In addition, the TVC was improved by 14.42-16.74% in target type 4 compared to the other target types. These improvements were larger in IMRT than in VMAT (27.99% vs. 6.34%). The V(30%) was not statistically different between IMRT and VMAT according to the MLC leaf widths and the types of target. CONCLUSION: The smaller MLC leaf width provided improved target coverage in both IMRT and VMAT, and its improvement was larger in IMRT than in VMAT. In addition, the smaller MLC leaf width was more effective for complex-shaped targets
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