6,981 research outputs found

    Microscopic theory of solvent mediated long range forces: influence of wetting

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    We show that a general density functional approach for calculating the force between two big particles immersed in a solvent of smaller ones can describe systems that exhibit fluid-fluid phase separation: the theory captures effects of strong adsorption (wetting) and of critical fluctuations in the solvent. We illustrate the approach for the Gaussian core model, a simple model of a polymer mixture in solution and find extremely attractive, long ranged solvent mediated potentials between the big particles for state points lying close to the binodal, on the side where the solvent is poor in the species which is favoured by the big particles.Comment: 7 pages, 3 figures, submitted to Europhysics Letter

    Mullin v. Ratheon Co.: The Threatened Vitality of Disparate Impact under the ADEA

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    Seven years after Congress enacted Title VII of the Civil Rights Act of 1964 (Title VII), and four years after the enactment of the Age Discrimination in Employment Act of 1967 (the ADEA), the Supreme Court, in Griggs v. Duke Power Co., enunciated the doctrine of disparate impact as a means of establishing liability under Title VII. Since that time, the doctrine has evolved considerably and its application and contours have been redefined by the Court as well as by Congress. Within this evolution there has been a debate among the courts and commentators as to whether the doctrine may be used to establish liability under the ADEA as well. In Mullin v. Raytheon Co., the First Circuit joined two other circuits answering that question in the negative, and held that a claim of disparate impact is not cognizable under the ADEA. This Note details the backdrop of the issue the First Circuit decided, starting in Part II with a discussion of the ADEA. This includes consideration of the purposes behind the ADEA, its similarities to Title VII, and a review of some of its salient provisions. This is followed by a discussion of employment discrimination claims, briefly outlining the disparate treatment theory and focusing on the disparate impact doctrine, including a review of how the doctrine has evolved over the years as well as the procedural aspects of presenting a disparate impact claim. Finally, this Note concludes that the First Circuit was correct in holding that disparate impact claims are not permitted under the ADEA based on the reasons it cited as well as other rationales relied upon by other courts and commentators

    The impact of prior information on estimates of disease transmissibility using Bayesian tools

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    The basic reproductive number (R₀) and the distribution of the serial interval (SI) are often used to quantify transmission during an infectious disease outbreak. In this paper, we present estimates of R₀ and SI from the 2003 SARS outbreak in Hong Kong and Singapore, and the 2009 pandemic influenza A(H1N1) outbreak in South Africa using methods that expand upon an existing Bayesian framework. This expanded framework allows for the incorporation of additional information, such as contact tracing or household data, through prior distributions. The results for the R₀ and the SI from the influenza outbreak in South Africa were similar regardless of the prior information (R0 = 1.36-1.46, μ = 2.0-2.7, μ = mean of the SI). The estimates of R₀ and μ for the SARS outbreak ranged from 2.0-4.4 and 7.4-11.3, respectively, and were shown to vary depending on the use of contact tracing data. The impact of the contact tracing data was likely due to the small number of SARS cases relative to the size of the contact tracing sample

    A study of Polygyra inflecta (Say)

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56715/1/OP276.pd

    What Canada Read/Red: A Content Media Analysis of the Montreal Olympic Games and the Soviet Union as Reported in the Montreal Gazette and The Globe and Mail

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    This study describes the media coverage of the 1976 Montreal Summer Olympic Games. Two newspapers were used for the data collection: the Montreal Gazette and The Globe and Mail. A systematic, descriptive content analysis of the Olympic Games news coverage was completed using 966 articles. Five categories were constructed for the quantitative analysis: general themes, change over time, sport, gender, and national representation. Based on the findings from the quantitative analysis, a qualitative analysis that examined the way in which the Soviet Union was represented in both newspapers was completed. Three dominant constructions were found, including sport dominance, political victimization, and national growth. This study shows that media focused heavily on the sporting aspect of the Games, compared to the academic literature, which focuses on key issues related to the Games, such as economics, politics, and infrastructure

    User benefits and funding strategies

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    The justification, economic and technological benefits of NASA Space Programs (aside from pure scientific objectives), in improving the quality of life in the United States is discussed and outlined. Specifically, a three-step, systematic method is described for selecting relevant and highly beneficial payloads and instruments for the Interim Upper Stage (IUS) that will be used with the space shuttle until the space tug becomes available. Viable Government and private industry cost-sharing strategies which would maximize the number of IUS payloads, and the benefits obtainable under a limited NASA budget were also determined. Charts are shown which list the payload instruments, and their relevance in contributing to such areas as earth resources management, agriculture, weather forecasting, and many others

    Ongoing transients in carbonate compensation

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    Uptake of anthropogenic CO2 is acidifying the oceans. Over the next 2000 years, this will modify the dissolution and preservation of sedimentary carbonate. By coupling new formulas for the positions of the calcite saturation horizon, zsat, the compensation depth, zcc, and the snowline, zsnow, to a biogeochemical model of the oceanic carbonate system, we evaluate how these horizons will change with ongoing ocean acidification. Our model is an extended Havardton-Bear-type box model, which includes novel kinetic descriptions for carbonate dissolution above, between, and below these critical depths. In the preindustrial ocean, zsat and zcc are at 3939 and 4750 m, respectively. When forced with the IS92a CO2 emission scenario, the model forecasts (1) that zsat will rise rapidly (“runaway” conditions) so that all deep water becomes undersaturated, (2) that zcc will also rise and over 1000 years will pass before it will be stabilized by the dissolution of previously deposited CaCO3, and (3) that zsnow will respond slowly to acidification, rising by ∼1150 m during a 2000 year timeframe. A further simplified model that equates the compensation and saturation depths produces quantitatively different results. Finally, additional feedbacks due to acidification on calcification and increased atmospheric CO2 on organic matter productivity strongly affect the positions of the compensation horizons and their dynamics.

    Generation of defects and disorder from deeply quenching a liquid to form a solid

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    We show how deeply quenching a liquid to temperatures where it is linearly unstable and the crystal is the equilibrium phase often produces crystalline structures with defects and disorder. As the solid phase advances into the liquid phase, the modulations in the density distribution created behind the advancing solidification front do not necessarily have a wavelength that is the same as the equilibrium crystal lattice spacing. This is because in a deep enough quench the front propagation is governed by linear processes, but the crystal lattice spacing is determined by nonlinear terms. The wavelength mismatch can result in significant disorder behind the front that may or may not persist in the latter stage dynamics. We support these observations by presenting results from dynamical density functional theory calculations for simple one- and two-component two-dimensional systems of soft core particles.Comment: 25 pages, 11 figure

    Density functional theory for the freezing of soft-core fluids

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    We present a simple density functional theory for the solid phases of systems of particles interacting via soft-core potentials. In particular, we apply the theory to particles interacting via repulsive point Yukawa and Gaussian pair potentials. We find qualitative agreement with the established phase diagrams for these systems. The theory is able to account for the bcc-fcc solid transitions of both systems and the re-entrant melting that the Gaussian system exhibits.Comment: 7 pages, 4 figure

    Estimating the reproductive number in the presence of spatial heterogeneity of transmission patterns

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    Background: Estimates of parameters for disease transmission in large-scale infectious disease outbreaks are often obtained to represent large groups of people, providing an average over a potentially very diverse area. For control measures to be more effective, a measure of the heterogeneity of the parameters is desirable. Methods: We propose a novel extension of a network-based approach to estimating the reproductive number. With this we can incorporate spatial and/or demographic information through a similarity matrix. We apply this to the 2009 Influenza pandemic in South Africa to understand the spatial variability across provinces. We explore the use of five similarity matrices to illustrate their impact on the subsequent epidemic parameter estimates. Results: When treating South Africa as a single entity with homogeneous transmission characteristics across the country, the basic reproductive number, R0, (and imputation range) is 1.33 (1.31, 1.36). When fitting a new model for each province with no inter-province connections this estimate varies little (1.23-1.37). Using the proposed method with any of the four similarity measures yields an overall R0 that varies little across the four new models (1.33 to 1.34). However, when allowed to vary across provinces, the estimated R0 is greater than one consistently in only two of the nine provinces, the most densely populated provinces of Gauteng and Western Cape. Conclusions: Our results suggest that the spatial heterogeneity of influenza transmission was compelling in South Africa during the 2009 pandemic. This variability makes a qualitative difference in our understanding of the epidemic. While the cause of this fluctuation might be partially due to reporting differences, there is substantial evidence to warrant further investigation
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