8,971 research outputs found

    Role of resonances in rho^0 -> pi^+ pi^- gamma

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    We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0 -> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are driven by the mass and width parameters of the sigma(600), and the usually neglected contribution of the a_1(1260), although small by itself, may become sizable through its interference with pion bremsstrahlung, and the proper relative sign can favor the central value of the experimental branching ratio. We present a procedure, using the gauge invariant structure of the resonant amplitudes, to kinematically enhance the resonant effects in the angular and energy distribution of the photon. We also elaborate on the coupling constants involved.Comment: 5 pages, 5 figures, accepted for publication in PR

    Planning a Culturally and Linguistically Appropriate Obesity Intervention for Hispanic/Latino Children Living in Rural Nebraska

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    Childhood obesity is a public health concern in the U.S; however, for the Hispanic/Latino community these concerns have grown to epic proportions. In Nebraska, the rate of childhood obesity is 25.1%; among Hispanic / Latinos students, the obesity rate is 30.9%. Unfortunately, specific Nebraska obesity rates by race and ethnicity are limited among rural communities, and programs that can effectively address this problem in the Hispanic / Latino community are limited or non-existent. Consequently, disparities between urban and rural communities exist. The purpose of this capstone project is to design a culturally and linguistically oriented intervention to address childhood obesity among the Hispanic/Latino community in a rural population. We used secondary data gathered from the literature on evidence-based childhood obesity programs for this population and from focus groups conducted among a Hispanic/Latino community during an APEx Learning project in Colfax County, Nebraska. This capstone project will also provide a full description of the program, logic model, implementation plan, evaluation plan, expected outcomes, strengths and limitations, sustainability, and budget. Finally, this intervention plan hopes to influence community leaders to adopt this project and for it to be implemented by the East Central District Health Department to reduce childhood obesity among the Hispanic/Latino community in Colfax County, Nebraska

    Periodic Chaotic Billiards: Quantum-Classical Correspondence in Energy Space

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    We investigate the properties of eigenstates and local density of states (LDOS) for a periodic 2D rippled billiard, focusing on their quantum-classical correspondence in energy representation. To construct the classical counterparts of LDOS and the structure of eigenstates (SES), the effects of the boundary are first incorporated (via a canonical transformation) into an effective potential, rendering the one-particle motion in the 2D rippled billiard equivalent to that of two-interacting particles in 1D geometry. We show that classical counterparts of SES and LDOS in the case of strong chaotic motion reveal quite a good correspondence with the quantum quantities. We also show that the main features of the SES and LDOS can be explained in terms of the underlying classical dynamics, in particular of certain periodic orbits. On the other hand, statistical properties of eigenstates and LDOS turn out to be different from those prescribed by random matrix theory. We discuss the quantum effects responsible for the non-ergodic character of the eigenstates and individual LDOS that seem to be generic for this type of billiards with a large number of transverse channels.Comment: 13 pages, 18 figure

    Factores reguladores de la monocigocia y dicigocia en España (2006)

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    En este trabajo se analiza la influencia de la edad materna, paridad, intervalo intergenési-co, estacionalidad del parto y el ambiente rural/urbano, definido en función del tamaño demográ-fico del lugar de residencia de la madre, sobre las frecuencias de gemelos monocigotos y dicigo-tos que se están produciendo recientemente en España. El estudio se ha realizado a partir de la información demográfica obtenida en la base de datos del Instituto Nacional de Estadística del año 2006. Los resultados indican que la monocigocia (gemelos idénticos) aumenta conforme lo hace la edad materna así como en los intervalos intergenésicos cortos (periodos entre embarazos consecutivos menores a dos años). Se ha comprobado que las mayores tasas de monocigocia se dan en ambientes rurales y que a partir del quinto embarazo la tasa de monocigocia disminuye mucho. En cuanto a la dicigocia, su frecuencia es mucho mayor en madres primerizas, en interva-los intergenésicos mayores de tres años y medio y en madres con edad avanzada. En primavera es donde se registran menos casos de dicigocia a lo largo del año

    Testing the cooling flow model in the intermediate polar EX Hydrae

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    We use the best available X-ray data from the intermediate polar EX Hydrae to study the cooling-flow model often applied to interpret the X-ray spectra of these accreting magnetic white dwarf binaries. First, we resolve a long-standing discrepancy between the X-ray and optical determinations of the mass of the white dwarf in EX Hya by applying new models of the inner disk truncation radius. Our fits to the X-ray spectrum now agree with the white dwarf mass of 0.79 M⊙_{\odot}sun determined using dynamical methods through spectroscopic observations of the secondary. We use a simple isobaric cooling flow model to derive the emission line fluxes, emission measure distribution, and H-like to He-like line ratios for comparison with the 496 ks Chandra High Energy Transmission Grating observation of EX Hydrae. We find that the H/He ratios are not well reproduced by this simple isobaric cooling flow model and show that while H-like line fluxes can be accurately predicted, fluxes of lower-Z He-like lines are significantly underestimated. This discrepancy suggests that some extra heating mechanism plays an important role at the base of the accretion column, where cooler ions form. We thus explored more complex cooling models including the change of gravitational potential with height in the accretion column and a magnetic dipole geometry. None of these modifications to the standard cooling flow model are able to reproduce the observed line ratios. While a cooling flow model with subsolar (0.1 ⊙\odot) abundances is able to reproduce the line ratios by reducing the cooling rate at temperatures lower than ∼107.3\sim 10^{7.3} K, the predicted line-to-continuum ratios are much lower than observed. We discuss and discard mechanisms such as photoionization, departures from constant pressure, resonant scattering, different electron-ion temperatures, and Compton cooling. [Abridged]Comment: Accepted in Astronomy & Astrophysics, modified version after referee comments and proof correction

    Assessment of Tourism Suitability and Carrying Capacity of Selected Tourist Sites in Tinambac, Camarines Sur, The Philippines

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    Achieving sustainable tourism requires tourist site management that is based on empirical studies. This paper utilized the analyses of the tourism suitability index and Boullon’s Carrying Capacity Mathematical Model (BCCMM) in assessing four selected tourist sites of Tinambac, Camarines Sur, which offers a wide range of tourist destinations. Results showed that all four sites have the following suitability index and carrying capacity: 76.19% with 43 persons per day; 80.95% with 60 persons per day; 86.90% with 359 persons per day; and 91.67% with 612 persons per day, respectively. Based on the assessment, the four selected tourist sites are suitable for tourism destinations
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