8,621 research outputs found

    THE ROLE OF STATED PREFERENCES AND DISCRETE CHOICE MODELS IN IDENTIFYING COMMUNITY PREFERENCES FOR TRAFFIC MANAGEMENT DEVICES

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    Responsible local governments recognise the need to be sensitive to the local environmental implications of decisions taken in the course of developing strategies to ensure the efficient use of scarce resources. Rather than rely on the pressures of lobby groups to direct government behaviour in relation to community concerns, a preferred strategy is to identify the preferences and choices of the community as a whole and to use information from a representative cross-section from the community to aid in making environmentally-linked decisions which maximise the benefits to the affected community. This paper demonstrates how discrete-choice models can be used to identify community choices amongst alternative traffic management devices designed to improve the traffic environment within and in the vicinity of local residential streets. Using a "before" and "after" survey strategy, the study provides evidence to support the view that a set of guidelines representing the communities preferences for different devices should be based on an empirical model estimated on a sample of residents who have already had exposure to a range of devices

    Segregation and linkage analysis for longitudinal measurements of a quantitative trait

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    We present a method for using slopes and intercepts from a linear regression of a quantitative trait as outcomes in segregation and linkage analyses. We apply the method to the analysis of longitudinal systolic blood pressure (SBP) data from the Framingham Heart Study. A first-stage linear model was fit to each subject's SBP measurements to estimate both their slope over time and an intercept, the latter scaled to represent the mean SBP at the average observed age (53.7 years). The subject-specific intercepts and slopes were then analyzed using segregation and linkage analysis. We describe a method for using the standard errors of the first-stage intercepts and slopes as weights in the genetic analyses. For the intercepts, we found significant evidence of a Mendelian gene in segregation analysis and suggestive linkage results (with LOD scores ≥ 1.5) for specific markers on chromosomes 1, 3, 5, 9, 10, and 17. For the slopes, however, the data did not support a Mendelian model, and thus no formal linkage analyses were conducted

    The Effects of Breed and Implant on Bullock Beef

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    Ninety-seven Angus and 98 Gelbvieh crossbred bulls were used to evaluate the effects of Ralgro, Synovex-H and Synovex-S implants on the growth, carcass and palatability traits of young bulls. The influence of the growth promoting implants on the feedlot performance of the bulls was dependent on their breed type and their stage growth. Percentage retail yield was the only carcass characteristic that was affected by the implants. The implanted bulls yielded carcasses with more external fat and less desirable yield grades than the controls. Rib eye area was not affected by the implants. Breed influenced feedlot performance, carcass composition and quality and palatability attributes more than the implants. The large-framed, late maturing Gelbvieh crossbred bulls grew faster and produced carcasses yielding higher percentages of boneless and produced carcasses yielding higher percentages of boneless trimmed retail cuts than the Angus bulls. The quality grades and palatability traits of the Gelbvieh bulls were marginal. The Angus bull carcasses has very acceptable yield grades (YG-2) and more desirable quality grades and sensory evaluations than the Gelbvieh crossbred bulls. Thus, the use of medium-framed intact males may be more appropriate than the larger framed breeds to produce a more acceptable product for both the packer and the consumer. Packer acceptability needs to be enhanced to make the use of intact males economically feasible for the producer

    Effects of Sex and Hormonal Implant on Beef Carcass Characteristics and Palatability

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    A comparison of crossbred bulls, steers and heifers indicated that bulls have heavier carcasses, larger rib eyes and a more desirable yield grade. The USDA quality grade of the bulls was one-third of a grade lower than for the steers and heifers. The sensory and palatability characteristics showed no significant differences among axes. Implanted bulls as compared to non-implanted bulls showed more desirable taste panel scores for tenderness, juiciness and overall panel desirability

    Prediction of Nonlinear Propagation of Noise from a Solid Rocket Motor

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    Nonlinear acoustic wave propagation predictions (Generalized Burgers equation-based) of noise propagation are compared with measurements from a static, horizontally-fired solid rocket motor over a range of 76-1220 m during an 80 s burn time. The modeling suggests the nature of the geometric spreading between 76 and 305 m varies from cylindrical at low-frequencies to spherical at high frequencies. The predicted waveforms and high-frequency spectral slopes associated with significant shock content are in agreement with properties of the measured noise. At 1220 m, the relatively simple nonlinear model again approximates the measured spectrum despite the complexities of the measurement environment and atmospheric propagation

    Does Positronium Form in the Universe ?

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    Positronium (the bound state of electron and positron) has been thought to be formed after proton decay (>1034>10^{34}yr) through collisional recombination and then decays by pair annihilation, thereby changing the matter content of the universe. We revisit the issue of the formation of positronium in the long-term future of the universe in light of recent indication that the universe is dominated by dark energy and dark matter. We find that if the equation of state of dark energy ww is less than -1/3 (including the cosmological constant w=−1w=-1), then the formation of positronium would not be possible, while it is possible through bound-bound transitions for -1/3\siml w\siml-0.2, or through collisional recombination for w\simg-0.2. The radiation from \epm pair annihilation cannot dominate over \epm, while that from proton decay will dominate over baryon and \epm for a while but not over dark matter.Comment: 13 pages, to appear in JCA

    Smelters and Mortality: Pope et al. Respond

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    Stigmergy: A key driver of self-organization in bacterial biofilms

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    Bacterial biofilms are complex multicellular communities that are often associated with the emergence of large-scale patterns across the biofilm. How bacteria self-organize to form these structured communities is an area of active research. We have recently determined that the emergence of an intricate network of trails that forms during the twitching motility mediated expansion of Pseudomonas aeruginosa biofilms is attributed to an interconnected furrow system that is forged in the solidified nutrient media by aggregates of cells as they migrate across the media surface. This network acts as a means for self-organization of collective behavior during biofilm expansion as the cells following these vanguard aggregates were preferentially confined within the furrow network resulting in the formation of an intricate network of trails of cells. Here we further explore the process by which the intricate network of trails emerges. We have determined that the formation of the intricate network of furrows is associated with significant remodeling of the sub-stratum underlying the biofilm. The concept of stigmergy has been used to describe a variety of self-organization processes observed in higher organisms and abiotic systems that involve indirect communication via persistent cues in the environment left by individuals that influence the behavior of other individuals of the group at a later point in time. We propose that the concept of stigmergy can also be applied to describe self-organization of bacterial biofilms and can be included in the repertoire of systems used by bacteria to coordinate complex multicellular behaviors

    Reading Videogames as (authorless) Literature

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    This article presents the outcomes of research, funded by the Arts and Humanities Research Council in England and informed by work in the fields of new literacy research, gaming studies and the socio-cultural framing of education, for which the videogame L.A. Noire (Rockstar Games, 2011) was studied within the orthodox framing of the English Literature curriculum at A Level (pre-University) and Undergraduate (degree level). There is a plethora of published research into the kinds of literacy practices evident in videogame play, virtual world engagement and related forms of digital reading and writing (Gee, 2003; Juul, 2005; Merchant, Gillen, Marsh and Davies, 2012; Apperley and Walsh, 2012; Bazalgette and Buckingham, 2012) as well as the implications of such for home / school learning (Dowdall, 2006; Jenkins, 2006; Potter, 2012) and for teachers’ own digital lives (Graham, 2012). Such studies have tended to focus on younger children and this research is also distinct from such work in the field in its exploration of the potential for certain kinds of videogame to be understood as 'digital transformations' of conventional ‘schooled’ literature. The outcomes of this project raise implications of such a conception for a further implementation of a ‘reframed’ literacy (Marsh, 2007) within the contemporary curriculum of a traditional and conservative ‘subject’. A mixed methods approach was adopted. Firstly, students contributing to a gamplay blog requiring them to discuss their in-game experience through the ‘language game’ of English Literature, culminating in answering a question constructed with the idioms of the subject’s set text ‘final examination’. Secondly, students taught their teachers to play L.A. Noire, with free choice over the context for this collaboration. Thirdly, participants returned to traditional roles in order to work through a set of study materials provided, designed to reproduce the conventions of the ‘study guide’ for literature education. Interviews were conducted after each phase and the outcomes informed a redrafting of the study materials which are now available online for teachers – this being the ‘practical’ outcome of the research (Berger and McDougall, 2012). In the act of inserting the study of L.A. Noire into the English Literature curriculum as currently framed, this research moves, through a practical ‘implementation’ beyond longstanding debates around narratology and ludology (Frasca, 2003; Juul, 2005) in the field of game studies (Leaning, 2012) through a direct connection to new literacy studies and raises epistemological questions about ‘subject identity’, informed by Bernstein (1996) and Bourdieu (1986) and the implications for digital transformations of texts for both ideas about cultural value in schooled literacy (Kendall and McDougall, 2011) and the politics of ‘expertise’ in pedagogic relations (Ranciere, 2009, Bennett, Kendall and McDougall, 2012a)
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