1,502 research outputs found

    Thermonuclear burn-up in deuterated methane CD4CD_4

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    The thermonuclear burn-up of highly compressed deuterated methane CD4_4 is considered in the spherical geometry. The minimal required values of the burn-up parameter x=ρ0rfx = \rho_0 \cdot r_f are determined for various temperatures TT and densities ρ0\rho_0. It is shown that thermonuclear burn-up in CD4CD_4 becomes possible in practice if its initial density ρ0\rho_0 exceeds 5103\approx 5 \cdot 10^3 gcm3g \cdot cm^{-3}. Burn-up in CD2_2T2_2 methane requires significantly (\approx 100 times) lower compressions. The developed approach can be used in order to compute the critical burn-up parameters in an arbitrary deuterium containing fuel

    Detection of elliptical shapes via cross-entropy clustering

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    The problem of finding elliptical shapes in an image will be considered. We discuss the solution which uses cross-entropy clustering. The proposed method allows the search for ellipses with predefined sizes and position in the space. Moreover, it works well for search of ellipsoids in higher dimensions

    The Conscience of Arkansas: The Progressive Reform Efforts of Adolphine Fletcher Terry, 1902-1976

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    This dissertation focuses on the progressive reform efforts of Adolphine Fletcher Terry, a social activist in Arkansas from 1902-1976. Terry was a white southern woman spurred to action during pivotal moments in Arkansas, southern, and national history. Her story revealed one side of social reform and racial progress in the South. Her reform efforts shed light on regional and women\u27s studies as well as on the intersection among class, gender, and race relations during the segregation era. Terry\u27s life story is a good example of the tug-of-war between southern tradition and modern change that many southern liberals dealt with during the twentieth century. She graduated from Vassar College in 1902, at the beginning of the Progressive movement, and upon her return to Arkansas she became involved in several important social reform efforts. She began her endeavors with public education reform, including the consolidation of one-room schools and addressing the transportation needs of rural students. She then turned her attention to the establishment of a juvenile court system and the founding of the Arkansas Girls Industrial School. Some of the other reform efforts she is known for include: the establishment of a College Club for college educated women in Little Rock, the women\u27s suffrage movement, establishment of the African American branch of the Young Women\u27s Christian Association in Little Rock, the creation of a statewide public library system, the Little Rock Urban League, the expansion of disablitiy services in Little Rock, and many other philanthropic endeavors across the state of Arkansas. On the national stage, she is best known for the formation of the Women\u27s Emergency Committee to Open Our Schools in 1958. Terry used her social status, network of clubwomen, and the media, specifically newspapers, to reach her goals. Her story explores the role of privileged white society women, who could and did have an impact on these important issues facing the South by agitating for change and working within the the white patriarchal system. While some acted from a sense of obligation, Terry made a very conscious choice to address the ills of society and put her efforts into improving the lives of all Arkansans

    The Evolution and Status of the Contributory Negligence Defense to Medical Malpractice Actions in North Carolina - McGill v. French

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    This Note will examine the defense of contributory negligence, the prerequisites for asserting the defense, and the underlying policy reasons which may explain the rampant growth of the defense and its alleged recent decline. Next, this Note will evaluate the circumstances which have given rise to contributory negligence as well as those circumstances that do not rise to the level of contributory negligence. Finally, this Note will analyze the North Carolina Supreme Court\u27s decision to permit the defense when the patient fails to follow the physician\u27s advice and instructions

    Latent class analysis variable selection

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    We propose a method for selecting variables in latent class analysis, which is the most common model-based clustering method for discrete data. The method assesses a variable's usefulness for clustering by comparing two models, given the clustering variables already selected. In one model the variable contributes information about cluster allocation beyond that contained in the already selected variables, and in the other model it does not. A headlong search algorithm is used to explore the model space and select clustering variables. In simulated datasets we found that the method selected the correct clustering variables, and also led to improvements in classification performance and in accuracy of the choice of the number of classes. In two real datasets, our method discovered the same group structure with fewer variables. In a dataset from the International HapMap Project consisting of 639 single nucleotide polymorphisms (SNPs) from 210 members of different groups, our method discovered the same group structure with a much smaller number of SNP

    Conscientiousness and fruit and vegetable consumption: exploring behavioural intention as a mediator

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    Clear associations have emerged between conscientiousness and health behaviours, such that higher levels of conscientiousness are predictive of beneficial health behaviours. This study investigated the conscientiousness-fruit and vegetable consumption relationship and whether behavioural intention mediated this relationship. A large sample of adults (N = 2136) completed an online battery of questionnaires measuring conscientiousness, behavioural intentions to consume fruit and vegetables, together with self-reported behaviour. Correlation analysis revealed that conscientiousness and each of its facets were positively associated with behavioural intention and self-reported behaviour. Hierarchical multiple regression analyses revealed that after controlling for age, gender and education, total conscientiousness, and the facets of responsibility, industriousness, order and virtue predicted self-reported behaviour. Further analysis revealed that in line with the Theory of Planned Behaviour, behavioural intention fully mediated the conscientiousness-fruit and vegetable behaviour relationship. In conclusion, low levels of conscientiousness were found to be associated with lower fruit and vegetable intentions, with the latter also associated with fruit and vegetable consumption

    Mining the UKIDSS GPS: star formation and embedded clusters

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    Data mining techniques must be developed and applied to analyse the large public data bases containing hundreds to thousands of millions entries. The aim of this study is to develop methods for locating previously unknown stellar clusters from the UKIDSS Galactic Plane Survey catalogue data. The cluster candidates are computationally searched from pre-filtered catalogue data using a method that fits a mixture model of Gaussian densities and background noise using the Expectation Maximization algorithm. The catalogue data contains a significant number of false sources clustered around bright stars. A large fraction of these artefacts were automatically filtered out before or during the cluster search. The UKIDSS data reduction pipeline tends to classify marginally resolved stellar pairs and objects seen against variable surface brightness as extended objects (or "galaxies" in the archive parlance). 10% or 66 x 10^6 of the sources in the UKIDSS GPS catalogue brighter than 17 magnitudes in the K band are classified as "galaxies". Young embedded clusters create variable NIR surface brightness because the gas/dust clouds in which they were formed scatters the light from the cluster members. Such clusters appear therefore as clusters of "galaxies" in the catalogue and can be found using only a subset of the catalogue data. The detected "galaxy clusters" were finally screened visually to eliminate the remaining false detections due to data artefacts. Besides the embedded clusters the search also located locations of non clustered embedded star formation. The search covered an area of 1302 square degrees and 137 previously unknown cluster candidates and 30 previously unknown sites of star formation were found

    The Sloan Great Wall. Morphology and galaxy content

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    We present the results of the study of the morphology and galaxy content of the Sloan Great Wall (SGW). We use the luminosity density field to determine superclusters in the SGW, and the fourth Minkowski functional V_3 and the morphological signature (the K_1-K_2 shapefinders curve) to show the different morphologies of the SGW, from a single filament to a multibranching, clumpy planar system. The richest supercluster in the SGW, SCl~126 and especially its core resemble a very rich filament, while another rich supercluster in the SGW, SCl~111, resembles a "multispider" - an assembly of high density regions connected by chains of galaxies. Using Minkowski functionals we study the substructure of individual galaxy populations determined by their color in these superclusters. We assess the statistical significance of the results with the halo model and smoothed bootstrap. We study the galaxy content and the properties of groups of galaxies in two richest superclusters of the SGW, paying special attention to bright red galaxies (BRGs) and to the first ranked galaxies in SGW groups. About 1/3 of BRGs are spirals. The scatter of colors of elliptical BRGs is smaller than that of spiral BRGs. About half of BRGs and of first ranked galaxies in groups have large peculiar velocities. Groups with elliptical BRGs as their first ranked galaxies populate superclusters more uniformly than the groups, which have a spiral BRG as its first ranked galaxy. The galaxy and group content of the core of the supercluster SCl~126 shows several differences in comparison with the outskirts of this supercluster and with the supercluster SCl~111. Our results suggest that the formation history and evolution of individual neighbour superclusters in the SGW has been different.Comment: Comments: 26 pages, 20 figures, accepted for publication in Ap

    The Sloan Great Wall. Rich clusters

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    We present the results of the study of the substructure and galaxy content of ten rich clusters of galaxies in three different superclusters of the Sloan Great Wall. We determine the substructure in clusters using the 'Mclust' package from the 'R' statistical environment and analyse their galaxy content. We analyse the distribution of the peculiar velocities of galaxies in clusters and calculate the peculiar velocity of the first ranked galaxy. We show that clusters in our sample have more than one component; in some clusters different components also have different galaxy content. We find that in some clusters with substructure the peculiar velocities of the first ranked galaxies are large. All clusters in our sample host luminous red galaxies. They can be found both in the central areas of clusters as well as in the outskirts, some of them have large peculiar velocities. About 1/3 of red galaxies in clusters are spirals. The scatter of colours of red ellipticals is in most clusters larger than that of red spirals. The presence of substructure in rich clusters, signs of possible mergers and infall, as well as the large peculiar velocities of the first ranked galaxies suggest that the clusters in our sample are not yet virialized. We present merger trees of dark matter haloes in an N-body simulation to demonstrate the formation of present-day dark matter haloes via multiple mergers during their evolution. In simulated dark matter haloes we find a substructure similar to that in observed clusters.Comment: 19 pages, 44 figures, accepted for publication in Astronomy and Astrophysic

    Adult attachment styles and the psychological response to infant bereavement

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    Background: Based on Bowlby's attachment theory, Bartholomew proposed a four-category attachment typology by which individuals judged themselves and adult relationships. This explanatory model has since been used to help explain the risk of psychiatric comorbidity. Objective: The current study aimed to identify attachment typologies based on Bartholomew's attachment styles in a sample of bereaved parents on dimensions of closeness/dependency and anxiety. In addition, it sought to assess the relationship between the resultant attachment typology with a range of psychological trauma variables. Method: The current study was based on a sample of 445 bereaved parents who had experienced either peri- or post-natal death of an infant. Adult attachment was assessed using the Revised Adult Attachment Scale (RAAS) while reaction to trauma was assessed using the Trauma Symptom Checklist (TSC). A latent profile analysis was conducted on scores from the RAAS closeness/dependency and anxiety subscales to ascertain if there were underlying homogeneous attachment classes. Emergent classes were used to determine if these were significantly different in terms of mean scores on TSC scales. Results: A four-class solution was considered the optimal based on fit statistics and interpretability of the results. Classes were labelled “Fearful,” “Preoccupied,” “Dismissing,” and “Secure.” Females were almost eight times more likely than males to be members of the fearful attachment class. This class evidenced the highest scores across all TSC scales while the secure class showed the lowest scores. Conclusions: The results are consistent with Bartholomew's four-category attachment styles with classes representing secure, fearful, preoccupied, and dismissing types. While the loss of an infant is a devastating experience for any parent, securely attached individuals showed the lowest levels of psychopathology compared to fearful, preoccupied, or dismissing attachment styles. This may suggest that a secure attachment style is protective against trauma-related psychological distress
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