452 research outputs found

    Degree of substitution in Ethylchlorosilanes

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    When an organo-magnesium halide is reacted with an excess of trichlorosilane, a mixture of products results according to the equations. If phenyl magnesium bromide is used, a mixture of high boiling products results, the highest boiling point of which is approximately 250° at 14mm. pressure. If ethyl magnesium bromide is used, it may be shown that, making certain assumptions and under the conditions of the experiment, if ethyl magnesium bromide is added to the trichlorosilane, monosubstitution is promoted, whereas if the trichlorosilane is added to the ethyl magnesium bromide, polysubstitution is promoted

    Awakening Imagination Through Literature

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    Great literature can inspire reflection and give birth to transforming grace. Words matter; and because they do, literature often reveals the human condition and suggests avenues for growth and change. This article explores the power of literature to cause a spiritual awakening in school leaders. Several works are discussed as the author leads readers into deeply poetic reflections on the possibility of healing and redemption through reading

    Introduction

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    A night on the town; New York Actor;The Philadelphia

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    The Marinello One-acts performed two plays each featuring a large city, comprise the Night on the Town experience from the Marinello One acts in February of 2002.https://collected.jcu.edu/plays/1127/thumbnail.jp

    Genome-wide association study of breast density among women of African ancestry

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    Breast density, the amount of fibroglandular versus fatty tissue in the breast, is a strong breast cancer risk factor. Understanding genetic factors associated with breast density may help in clarifying mechanisms by which breast density increases cancer risk. To date, 50 genetic loci have been associated with breast density, however, these studies were performed among predominantly European ancestry populations. We utilized a cohort of women aged 40-85 years who underwent screening mammography and had genetic information available from the Penn Medicine BioBank to conduct a Genome-Wide Association Study (GWAS) of breast density among 1323 women of African ancestry. For each mammogram, the publicly available LIBRA software was used to quantify dense area and area percent density. We identified 34 significant loci associated with dense area and area percent density, with the strongest signals i

    Small-world phenomena and the statistics of linear polymer networks

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    A regular lattice in which the sites can have long range connections at a distance l with a probabilty P(l)∼l−δP(l) \sim l^{-\delta}, in addition to the short range nearest neighbour connections, shows small-world behaviour for 0≤δ<δc0 \le \delta < \delta_c. In the most appropriate physical example of such a system, namely the linear polymer network, the exponent δ\delta is related to the exponents of the corresponding n-vector model in the n→0n \to 0 limit, and its value is less than δc\delta_c. Still, the polymer networks do not show small-world behaviour. Here, we show that this is due a (small value) constraint on the number q of long range connections per monomer in the network. In the general δ−q\delta - q space, we obtain a phase boundary separating regions with and without small-world behaviour, and show that the polymer network falls marginally in the regular lattice region.Comment: Minor corrections in text, Fig. 3 replace

    Development and Validation of the Weight Control Strategies Scale

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    Objective To develop and validate the Weight Control Strategies Scale (WCSS), a self-report instrument to assess use of specific behaviors thought to facilitate weight loss. Design and Methods Factor analysis was conducted on 323 overweight and obese adults (mean age=48.7±10.9 years, mean BMI=35.4±4.9 kg/m2, 74% female) enrolled in three different behavioral weight loss trials who completed the WCSS prior to starting treatment. To evaluate construct validity, additional data on dietary intake, physical activity, treatment session attendance, and weight change were obtained from a subsample of participants before and after participation in a 48-week weight loss program. Results Principal components analysis with varimax rotation revealed a four component solution for the WCSS, representing the following subscales: Dietary Choices, Self-monitoring Strategies, Physical Activity, and Psychological Coping (a’s from 0.79–0.89). Longitudinal analyses showed that WCSS subscale scores increased during treatment (p’s \u3c0.01). In adjusted models, changes in WCSS total and subscale scores were associated with posttreatment weight loss (p’s \u3c0.01). Additionally, changes in WCSS Dietary Choices and Physical Activity subscales were related to posttreatment changes in total daily kilocalorie consumption (p=0.019) and weekly kilocalorie expenditure through physical activity (p\u3c0.001), respectively. Conclusions Findings support the validity and reliability of the WCSS in a weight loss treatment seeking sample

    Automatic Network Fingerprinting through Single-Node Motifs

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    Complex networks have been characterised by their specific connectivity patterns (network motifs), but their building blocks can also be identified and described by node-motifs---a combination of local network features. One technique to identify single node-motifs has been presented by Costa et al. (L. D. F. Costa, F. A. Rodrigues, C. C. Hilgetag, and M. Kaiser, Europhys. Lett., 87, 1, 2009). Here, we first suggest improvements to the method including how its parameters can be determined automatically. Such automatic routines make high-throughput studies of many networks feasible. Second, the new routines are validated in different network-series. Third, we provide an example of how the method can be used to analyse network time-series. In conclusion, we provide a robust method for systematically discovering and classifying characteristic nodes of a network. In contrast to classical motif analysis, our approach can identify individual components (here: nodes) that are specific to a network. Such special nodes, as hubs before, might be found to play critical roles in real-world networks.Comment: 16 pages (4 figures) plus supporting information 8 pages (5 figures

    Networking - A Statistical Physics Perspective

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    Efficient networking has a substantial economic and societal impact in a broad range of areas including transportation systems, wired and wireless communications and a range of Internet applications. As transportation and communication networks become increasingly more complex, the ever increasing demand for congestion control, higher traffic capacity, quality of service, robustness and reduced energy consumption require new tools and methods to meet these conflicting requirements. The new methodology should serve for gaining better understanding of the properties of networking systems at the macroscopic level, as well as for the development of new principled optimization and management algorithms at the microscopic level. Methods of statistical physics seem best placed to provide new approaches as they have been developed specifically to deal with non-linear large scale systems. This paper aims at presenting an overview of tools and methods that have been developed within the statistical physics community and that can be readily applied to address the emerging problems in networking. These include diffusion processes, methods from disordered systems and polymer physics, probabilistic inference, which have direct relevance to network routing, file and frequency distribution, the exploration of network structures and vulnerability, and various other practical networking applications.Comment: (Review article) 71 pages, 14 figure
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