6,022 research outputs found
A new physical phenomenon in ultra-high energy collisions
We show that combining the published Pierre Auger Observatory measurements of
the longitudinal_and_ lateral properties of UHE atmospheric showers, points to
an unforeseen change in the nature of particle interactions at ultrahigh
energy. A "toy model" of UHE proton-air interactions is presented which
provides the first fully consistent description of air shower observations. It
demonstrates that the observed energy dependence of the depth-of-shower-maximum
distribution may not indicate a transition to a heavier composition, as
commonly assumed. While fundamentally phenomenological, the model is based on
considerations of how the normal vacuum of QCD might be vaporized and chiral
symmetry restored by the extreme energy densities produced in UHE collisions.
Whatever its origin, understanding this unexpected phenomenon opens exciting
directions in particle physics and may impact Early Universe cosmology.Comment: Based on talk given Feb. 14, 2012 at UHECR 2012 - International
Symposium on Future Directions in UHECR Physics, CERN, Genev
Precipitating Factors Influencing Obesity Rates in Indiana
Nearly two-thirds of the American population is now overweight, and the rate of obesity has doubled since the early 1960s. The state of Indiana has elected to forgo Medicaid expansion available through the Affordable Care Act of 2010 (ACA), which includes funding specific to obesity and obesity-related comorbidities. Utilizing the Robert Wood Johnson Foundation 2014 Health Statistics, causative obesity factors found in current research literature is examined for Indiana’s 92 counties. The variables are examined to determine significant correlation with adult levels of obesity. The significant variables (smoking, unemployment levels, physical inactivity) found in the correlation are then placed in a multivariate regression. The three combined variables explain 16 percent (R2 = .16) of Indiana’s current obesity percentage (31 percent). The only significant variable found in the regression matrix is the physical inactivity percentage (β = .21, t = 2.29, p \u3c .05). Funding found within the ACA, specifically Community Transformation Grants (CTG), provide an opportunity for Indiana to address the physical inactivity found statewide. CTG grants are available to states, counties, and municipalities, provided the funds address physical inactivity, healthy living improvements, obesity reduction, or smoking-cessation efforts
Microcomputer Playfulness: An Antecedent to Understanding User Intention to Adopt
This study investigates the relationship between microcomputer playfulness, an individual’s intention to adopt an information technology (IT), and their attitude toward adopting an IT. Analysis indicates that microcomputer playfulness is a significant variable in the determination of attitude toward adopting an information technology as well as end-user intention to adopt. The identification of high and low playfulness individuals, and the characteristics they deem important regarding innovations, allow the organization to customize technology introduction, training and implementation processes as to increase the likelihood of successful technology diffusion. The study identifies a significance of microcomputer playfulness as a behavioral input into innovation diffusion theory that has yet to be previously investigated from a technology adoption perspective
Land Cover Change in Mixed Agroforestry: Shade Coffee in El Salvador
Little is known about land cover change in mixed agroforestry systems, which often supply valuable ecological services. We use a spatial regression model to analyze clearing in El Salvador’s shade coffee–growing regions during the 1990s. Our findings buttress previous research suggesting the relationship between proximity to cities and clearing in mixed agroforestry systems is the opposite of that in natural forests. But this result, and several others, depends critically on the characteristics of the growing area, particularly the dominant cleared land use. These findings imply that policies aimed at retaining mixed agroforestry need to be carefully targeted and tailored.agroforestry, shade coffee, land cover, El Salvador, spatial econometrics
Tree Cover Loss in El Salvador's Shade Coffee Areas
Shade coffee farms in Central America provide important ecological services. But because international coffee prices have fallen since 1990, many have been cleared to make way for more remunerative land uses. This problem is of particular concern in heavily deforested El Salvador, where a large share of the remaining tree cover is associated with shade coffee. We use satellite images, stakeholder interviews, and secondary data to analyze the magnitude, characteristics, and drivers of clearing in El Salvador’s shade coffee areas during the 1990s. We find that 13 percent of these areas was cleared, mostly in middle- and high-altitude regions. Falling coffee prices were not the only drivers of this phenomenon, however: a downward spiral of on-farm investment and yields, debt, poverty, urbanization, migration, and weak land use regulation also contributed. Our findings suggest that stricter enforcement of land use and land cover regulations is urgently needed to prevent further clearing.shade coffee, land use, land cover, deforestation, El Salvador
The effect of peer and parental smoking on adolescent smoking initiation: Exploring potential moderators
The factors that contribute to smoking initiation among adolescents are poorly understood. The current approaches to smoking prevention may have achieved their maximum potential as evidenced by a stalling in the decline in smoking rates. To date, approaches to smoking prevention based on social and individual factors have previously met with limited success. A promising new approach will be to examine the interaction between social and individual factors and the effects of their interaction on smoking initiation. Parental and peer smoking behaviors are well-known risk factors for smoking initiation. Several theoretical models suggest that perceptual or interpretative processes may moderate the influence of factors such as these on the smoking initiation process. This study looks at age (as a proxy for adolescent development), depression and school performance as potential moderators of the impact of parental or peer smoking. This study uses a large longitudinal sample (The Teenage Attitudes and Practices Surveys -- 1989 and 1993) to explore for these relationships. Results show very limited support for the impact of potential moderated relationships, with only one of the six hypothesized interactions being supported (peer smoking and school performance). This would suggest that theoretical models which include concepts of perceptual or interpretative processes as moderating influences need to continue to evaluate their validity. Another finding of the study is a significant main effect of school performance on smoking initiation --a relationship which has not been previously reported in a national longitudinal sample. This study also found support for depression as an antecedent to smoking initiation -- a relationship whose causal direction continues to be controversial. Continued exploration of the complex relationships between these social and individual factors may allow for the development of more effective evidence-based smoking prevention programs
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