1,938 research outputs found

    Are there economic returns from democracy? : the experience of Sub-Saharan Africa from 1988-2007

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    There is an enduring debate as to whether democracy promotes or hinders economic growth. This study examines the relationship between democracy and economic growth in 47 sub-Saharan African countries from 1988 to 2007. From the late 1980s until the mid-1990s, a period of democratization swept the continent. This period of democratization was followed by a period of strong economic growth from the mid- 1990s through 2007. It is argued here that these events are not coincidental and that democracy is advantageous to economic growth, particularly in the sub-Saharan Africa region. Using statistical analyses such as bivariate correlation and multiple regression, the relationship between democracy and economic growth is examined using a number of control variables to test the strength of the relationship between democracy and growth. To date, the empirical research on democracy and economic growth provides conflicting results, ranging from positive to negative to neutral effects. The results of this study show that there is a correlation between higher levels of democracy and higher levels of economic growth during certain periods. However, this relationship weakens to levels that are not significant once certain combinations of control variables are included. While the results of the study do not provide a definitive answer to the debate, they do refute certain arguments that have been made about the main drivers of economic growth in the region. The results also show that democracy does not have a negative effect on growth, which highly suggests that there might be a sequence effect involved in the path towards democratization and economic growth

    A Mixed Method Approach for Evaluating and Improving the Design of Learning in Puzzle Games

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    Despite the acknowledgment that learning is a necessary part of all gameplay, the area of Games User Research lacks an established evidence based method through which designers and researchers can understand, assess, and improve how commercial games teach players game-specific skills and information. In this paper, we propose a mixed method procedure that draws together both quantitative and experiential approaches to examine the extent to which players are supported in learning about the game world and mechanics. We demonstrate the method through presenting a case study of the game Portal involving 14 participants, who differed in terms of their gaming expertise. By comparing optimum solutions to puzzles against observed player performance, we illustrate how the method can indicate particular problems with how learning is structured within a game. We argue that the method can highlight where major breakdowns occur and yield design insights that can improve the player experience with puzzle games

    Using Genetic Programming to Investigate a Novel Model of Resting Energy Expenditure for Bariatric Surgery Patients

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    Traditionally, models developed to estimate resting energy expenditure (REE) in the bariatric population have been limited to linear modelling based on data from `normal' or `overweight' individuals - not `obese'. This type of modelling can be restrictive and yield functions which poorly estimate this important physiological outcome.Linear and nonlinear models of REE for individuals after bariatric surgery are developed with linear regression and symbolic regression via genetic programming. Features not traditionally used in REE modelling were also incorporated and analyzed and genetic programming's intrinsic feature selection was used as a measure of feature importance.A collection of effective new linear and nonlinear models were generated. The linear models generated outperformed the nonlinear on testing data, although the nonlinear models fit the training data better. Ultimately, the newly developed linear models showed an improvement over existing models and the feature importance analysis suggested that the typically used features (age, weight, and height) were the most important

    Lithium abundances of halo dwarfs based on excitation temperature. I. LTE

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    The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe (WMAP) in determining the baryon density, OmegaBh^2, there was a discrepancy between observationally determined and theoretically determined abundances in the case of 7Li. One of the most important uncertain factors in the calculation of the stellar 7Li abundance is the effective temperature, Teff. We use sixteen metal-poor halo dwarfs to calculate new Teff values using the excitation energy method. With this temperature scale we then calculate new Li abundances for this group of stars in an attempt to resolve the 7Li discrepancy. Using high signal-to-noise (S/N ~ 100) spectra of 16 metal-poor halo dwarfs, obtained with the UCLES spectrograph on the AAT, measurements of equivalent widths from a set of unblended FeI lines are made. These equivalent widths are then used to calculate new Teff values with the use of the single line radiative transfer program WIDTH6, where we have constrained the gravity using either theoretical isochrones or the Hipparcos parallax, rather than the ionization balance. The lithium abundances of the stars are calculated with these temperatures. The physical parameters are derived for the 16 programme stars, and two standards. These include Teff, log g, [Fe/H], microturbulence and 7Li abundances. A comparison between the temperature scale of this work and those adopted by others has been undertaken. We find good consistency with the temperatures derived from the Halpha line by Asplund et al. (2006), but not with the hotter scale of Melendez & Ramirez (2004).Comment: 13 pages, 9 figure

    Bullous Allergic Hypersensitivity to Bed Bug Bites Mediated by IgE against Salivary Nitrophorin

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    In Central Europe, bites from the common bed bug (Cimex lectularius) are nowadays rather uncommon. Nevertheless, infestations are sometimes observed in old framehouses and by immigration due to international travel and migration. The clinical picture of bug bites substantially varies between individuals, depending upon previous exposure and the degree of an immune response. The host immune response and potential protein antigens present in the saliva of C. lectularius or specific antibodies have not been characterized thus far. We describe a patient with bullous bite reactions after sequential contact with C. lectularius over a period of 1 year. In skin tests, we observed immediate reactions to the salivary gland solution of C. lectularius, which were followed by a pronounced partially blistering late-phase response. Immunoblot analysis of the patient's serum with salivary gland extracts and recombinant C. lectularius saliva proteins revealed specific IgE antibodies against the 32kDa C. lectularius nitrophorin, but not to 37kDa C. lectularius apyrase. Our data demonstrate that bullous cimicosis may be the late-phase response of an allergic IgE-mediated hypersensitivity to C. lectularius nitrophorin

    Can Collegiate Hockey Players Accurately Predict Regional and Total Body Physiologic Changes throughout the Competitive Season?

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    A collegiate athlete’s body composition can fluctuate due to factors such as nutrition, sleep, and training load. As changes in body composition can affect an athlete’s level of performance, it may be beneficial if athlete’s can accurately predict these changes throughout a season. The purpose of this study was to determine how well a group of 23 male collegiate hockey players (age = 22.44 ± 1.16 years, height = 181.30 ± 6.99 cm, weight = 86.41 ± 8.32 kg) could predict their regional and total body lean and fat tissue mass throughout a hockey season (September to March). Total body, trunk, lower body, and upper body compositional changes were measured at the beginning and at the end of the competitive season using dual energy X-Ray absorptiometry (DXA). At the end of the season, a questionnaire was completed by each participant to explore how they perceived their body composition changes (losses or gains in lean tissue and fat mass) throughout the season. Overall, players had a difficult time identifying actual changes in lean tissue and fat mass throughout the season. Upper body fat and lean tissue changes were perceived most accurately, while perceptions of body fat were related to android adiposity but not visceral adiposity. These findings suggest that some regional areas of body composition changes may happen without being noticed. For strength and conditioning coaches, if athletes are made aware of these changes before they become exaggerated, proper dietary, and training adaptations can be made to enhance performance
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