3,946 research outputs found

    Noise Assessment/Survey at ERAU Fleet Maintenance Hanger

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    One of the many hazards associated with aviation, and conducting aircraft maintenance, is the issuance of noise hazards. Federal agencies such as Occupational Health and Safety Administration have incorporated standards pertaining to threshold limit values and permissible exposure limits surrounding noise in the workplace. Our objective is to assist the work environment in the Embry-Riddle aviation hangar to assure personnel are protected from lasting effects of noise through this research. The method used for research in this paper was a combination of sound monitoring of the maintenance hangar using a sound level meter, noise dosimeter and the NIOSH Sound Level Meter application as well as using relevant previous research studies. The results of the sound monitoring determined that the noise level within the maintenance hangar was well below the OSHA Time Weighted Average of 85 dB, and the noise level peaked at 115.4 dB for a single impulse. It has been concluded that the maintenance hangar does not require a hearing conservation program at this time as the data indicates that noise levels are well within OSHA standards. However, the current data does not include the engine run-up operations

    Relación del conocimiento del etiquetado “Semáforo Nutricional” en el estado nutricional de adolescentes ecuatorianos/List of labeling knowledge: "Nutritional traffic light" in the nutritional status of Ecuadorian adolescents

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    El semáforo nutricional (SN) es un tipo de etiquetado de alimentos creado para mejorar la comprensión del contenido de nutrientes (sodio, azúcar y grasa) en los alimentos procesados. En Ecuador, el SN es de uso obligatorio desde el año 2012. Objetivo: Evaluar la relación del conocimiento del etiquetado SN en el estado nutricional de adolescentes ecuatorianos. Métodos: Estudio transversal. Con 599 adolescentes (14- 18 años). Se recopilaron datos antropométricos, actividad física (IPAQ-A) e ingesta alimentaria utilizando 3 encuestas de recordatorio de 24 horas, el conocimiento del SN se evaluó con un cuestionario preparado para este fin: puntuaciones >5 significaron adecuado conocimiento (AC). Las relaciones entre las variables se determinaron mediante prueba t de student, utilizando el software STATA-14. Resultados: 55% de los adolescentes presentaron diagnóstico de sobrepeso, el 28% obesidad, según los indicadores IMC//Edad, el 48% un AC. Los adolescentes que mostraron inadecuado conocimiento evidenciaron medias más altas de IMC//edad, circunferencia de la cintura, circunferencia de la cadera y porcentaje de masa grasa (p<0.001), no se encontró diferencias en la ingesta alimentaria y conocimiento del SN. Conclusiones: El conocimiento del SN puede estar relacionado con el sobrepeso-obesidad en adolescentes, se necesita realizar más estudios para conocer cuál es el impacto de SN sobre el estado nutricional de la población en general. Nutritional traffic light (NT) is a type of food labeling created to improve the understanding of nutrient content (sodium, sugar and fat) in industrialized foods. In Ecuador, the TN is mandatory since 2012. Objective: To evaluate the relationship of NT labeling knowledge in the nutritional status of Ecuadorian adolescents. Methods: cross-sectional study. With 600 teenagers (14-18 years old). Anthropometric data, physical activity (IPAQ-A), and food intake were collected using 3 reminder surveys of 24 hours. Knowledge of NT was assessed with a questionnaire prepared for this purpose: scores> 5 meant adequate knowledge (AK). The relationships between the variables were determined by student’s T-test, using the STATA-14 software. Results: 55% of the adolescents presented a diagnosis of overweight and 28% of the adolescents presented a diagnosis of obesity according to the BMI indicators // age 48% presented a AK. Adolescents who presented inadequate knowledge presented higher means of BMI // age, waist circumference, hip circumference and percentage of fat mass (p <0.001), no differences were found in food intake and NT knowledge. Conclusions: Knowledge of NT may be related to overweight-obesity in adolescents, more studies are needed to establish these associations. Palabras clave: Semáforo nutricional, estado nutricional, adolescentes, Ecuador. Keywords: Nutritional traffic light, nutritional status, adolescents, Ecuador

    Interband electron Raman scattering in a quantum wire in a transverse magnetic field

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    Electron Raman scattering (ERS) is investigated in a parabolic semiconductor quantum wire in a transverse magnetic field neglecting by phonon-assisted transitions. The ERS cross-section is calculated as a function of a frequency shift and magnetic field. The process involves an interband electronic transition and an intraband transition between quantized subbands. We analyze the differential cross-section for different scattering configurations. We study selection rules for the processes. Some singularities in the Raman spectra are found and interpreted. The scattering spectrum shows density-of-states peaks and interband matrix elements maximums and a strong resonance when scattered frequency equals to the "hybrid" frequency or confinement frequency depending on the light polarization. Numerical results are presented for a GaAs/AlGaAs quantum wire.Comment: 8 pages, 5 figure

    New Measurements and Quantitative Analysis of Electron Backscattering in the Energy Range of Neutron Beta-Decay

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    We report on the first detailed measurements of electron backscattering from plastic scintillator targets, extending our previous work on beryllium and silicon targets. The scintillator experiment posed several additional experimental challenges associated with charging of the scintillator target, and those challenges are addressed in detail. In addition, we quantitatively compare the energy and angular distributions of this data, and our previous data, with electron transport simulations based on the Geant4 and Penelope Monte Carlo simulation codes. The Penelope simulation is found globally to give a superior description of the data. Such information is crucial for a broad array of weak-interaction physics experiments, where electron backscattering can give rise to the dominant detector-related systematic uncertainty.Comment: 7 pages, 3 figure

    HIV-exposed uninfected children. A systematic review on psychological well-being and association with school performances in Africa

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    There is a growing number of children affected by HIV in Africa. Research on HIV-exposed uninfected children (HEU) is also growing. This systematic review focuses on the psychological well-being of HEU and its association with school intervention, outcomes, and enrollment in the African context, which is where the rate of HIV reaches its highest levels. Research on public databases was conducted according to PRISMA standards. Only studies on HEU primary school children in Africa, both quantitative and qualitative, were included. Out of 1510 papers retrieved, 50 met the inclusion criteria. These studies demonstrate that HEU children are more likely to perform worse in school compared to their counterparts who were not exposed to HIV and to show poorer concentration in the classroom. Children with parents suffering from AIDS are worried for them and have to take household responsibility, resulting in school dropouts, juvenile work, and risky behaviors. Few interventions have been conducted in the school environment with some of them being successful; therefore, future research should involve schools to create an inclusive environment where HEU children could enhance their potential and improve their psychological health

    Thermodynamics of protein folding: a random matrix formulation

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    The process of protein folding from an unfolded state to a biologically active, folded conformation is governed by many parameters e.g the sequence of amino acids, intermolecular interactions, the solvent, temperature and chaperon molecules. Our study, based on random matrix modeling of the interactions, shows however that the evolution of the statistical measures e.g Gibbs free energy, heat capacity, entropy is single parametric. The information can explain the selection of specific folding pathways from an infinite number of possible ways as well as other folding characteristics observed in computer simulation studies.Comment: 21 Pages, no figure

    Local Extinction and Unintentional Rewilding of Bighorn Sheep (Ovis canadensis) on a Desert Island

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    Bighorn sheep ( Ovis canadensis) were not known to live on Tiburón Island, the largest island in the Gulf of California and Mexico, prior to the surprisingly successful introduction of 20 individuals as a conservation measure in 1975. Today, a stable island population of ∼500 sheep supports limited big game hunting and restocking of depleted areas on the Mexican mainland. We discovered fossil dung morphologically similar to that of bighorn sheep in a dung mat deposit from Mojet Cave, in the mountains of Tiburón Island. To determine the origin of this cave deposit we compared pellet shape to fecal pellets of other large mammals, and extracted DNA to sequence mitochondrial DNA fragments at the 12S ribosomal RNA and control regions. The fossil dung was 14C-dated to 1476-1632 calendar years before present and was confirmed as bighorn sheep by morphological and ancient DNA (aDNA) analysis. 12S sequences closely or exactly matched known bighorn sheep sequences; control region sequences exactly matched a haplotype described in desert bighorn sheep populations in southwest Arizona and southern California and showed subtle differentiation from the extant Tiburón population. Native desert bighorn sheep previously colonized this land-bridge island, most likely during the Pleistocene, when lower sea levels connected Tiburón to the mainland. They were extirpated sometime in the last ∼1500 years, probably due to inherent dynamics of isolated populations, prolonged drought, and (or) human overkill. The reintroduced population is vulnerable to similar extinction risks. The discovery presented here refutes conventional wisdom that bighorn sheep are not native to Tiburón Island, and establishes its recent introduction as an example of unintentional rewilding, defined here as the introduction of a species without knowledge that it was once native and has since gone locally extinct

    Random walks in the space of conformations of toy proteins

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    Monte Carlo dynamics of the lattice 48 monomers toy protein is interpreted as a random walk in an abstract (discrete) space of conformations. To test the geometry of this space, we examine the return probability P(T)P(T), which is the probability to find the polymer in the native state after TT Monte Carlo steps, provided that it starts from the native state at the initial moment. Comparing computational data with the theoretical expressions for P(T)P(T) for random walks in a variety of different spaces, we show that conformational spaces of polymer loops may have non-trivial dimensions and exhibit negative curvature characteristic of Lobachevskii (hyperbolic) geometry.Comment: 4 pages, 3 figure

    Review of Reactor Antineutrino Experiments

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    As discussed elsewhere, the measurement of a non-zero value for θ13\theta_{13} would open up a wide range of possibilities to explore CP-violation and the mass hierarchy. Experimental methods to measure currently the unknown mixing angle θ13\theta_{13} include accelerator searches for the νe\nu_{e} appearance and precise measurements of reactor antineutrino disappearance. The reactor antineutrino experiments are designed to search for a non-vanishing mixing angle θ13\theta_{13} with unprecedented sensitivity. This document describes current reactor antineutrino experiments and synergy between accelerator searches for the νe\nu_{e} appearance and precise measurements of reactor antineutrino disappearance.Comment: 8 pages, 2 figures, Review talk given at NuFact 2011, XIIIth InternationalWorkshop on Neutrino Factories, Super beams and Beta beams, CERN/UNIGE, Geneva, Switzerland, August 1-6, 201

    A Process for Co-Designing Educational Technology Systems for Refugee Children

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    There is a growing interest in the potential for technology to facilitate emergency education of refugee children. However, designing in this space requires knowledge of the displaced population and the contextual dynamics surrounding it. Design should therefore be informed by both existing research across relevant disciplines, and from the practical experience of those who are on the ground facing the problem in real life. This paper describes a process for designing appropriate technology for these settings. The process draws on literature from emergency education, student engagement and motivation, educational technology, and participatory design. We emphasise a thorough understanding of the problem definition, the nature of the emergency, and of socio-cultural aspects that can inform the design process. We describe how this process was implemented leading to the design of a digital learning space for children living in a refugee camp in Greece. This drew on involving different groups of participants such as social-workers, parents, and children
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