Adolescent tobacco use: Studies of prevalence, factorial validity, and factorial invariance between African Americans and Whites

In the last thirty years, increasing efforts have been made to reduce the prevalence of adolescent tobacco use in the United States. Although the prevalence has declined dramatically over the past decade, there are still sharp differences in adolescent smoking-initiation rates across racial/ethnic groups. Large-scale surveys frequently assess smoking-related attitudes, self-efficacy, and intentions to explain the differences in smoking rates between African Americans and Whites. However, there is little agreement about which constructs are significant. Moreover, the psychometric properties of smoking-related attitude, self-efficacy, and intention constructs have not been fully examined. More studies are needed to understand existing patterns of tobacco use and to validate and fully exploit the constructs' relationship to adolescent smoking initiation across racial/ethnic groups. ^ This dissertation reports on a secondary analysis of data from a large multi-ethnic convenience sample of sixth- through eighth-grade students in 22 schools in East Texas and the city of Houston. The specific aims of this dissertation were to (1) describe smoking and alternate tobacco product use rates by race/ethnicity, gender, age, and grade level (Article 1); (2) test the factorial validity of smoking-related attitudes, self-efficacy, and intentions using confirmatory factor analysis techniques (Article 2); and (3) test the factorial invariance of smoking-related attitudes, self-efficacy, and intentions between African Americans and Whites (Article 3). ^ The prevalence findings confirm the disparities in tobacco use among African American, Hispanic, and White adolescents that other surveys have reported (Article 1). This study also demonstrates the usefulness of examining use patterns of not only cigarettes but also alternative tobacco products in younger multiethnic populations, as well as of providing epidemiological data estimates about different phases of smoking. The confirmatory factor analysis provides evidence of construct validity of attitude, self-efficacy, and intention scales for the multiethnic sample (Article 2). Finally, the factorial invariance analyses indicates that some measures representing smoking-related attitudes, self-efficacy, and intentions may not be appropriate for use among both African Americans and Whites (Article 3). Additional research is needed to further our understanding of the patterns and predictors of youth tobacco use initiation. ^

Mathematical and empirical examinations of some epidemiological procedures

In epidemiology literature, it is often required to investigate the relationships between means where the levels of experiment are actually monotone sets forming a partition on the range of sampling values. With this need, the analysis of these group means is generally performed using classical analysis of variance (ANOVA). However, this method has never been challenged. In this dissertation, we will formulate and present our examination of its validity. First, the classical assumptions of normality and constant variance are not always true. Second, under the null hypothesis of equal means, the test statistic for the classical ANOVA technique is still valid. Third, when the hypothesis of equal means is rejected, the classical analysis techniques for hypotheses of contrasts are not valid. Fourth, under the alternative hypothesis, we can show that the monotone property of levels leads to the conclusion that the means are monotone. Fifth, we propose an appropriate method for handing the data in this situation. ^

Magnetic properties and chemical composition at DSDP Hole 77-538A

Magnetic properties of doleritic and some metamorphic basement rocks underlying Catoche Knoll are studied. Doleritic rocks show a high saturation magnetic moment (2-5 emu/g) compared to metamorphic rocks (0.1-1 emu/g). Magnetic minerals of rocks from this hole show a high stability when heated in vacuo up to 600°C at a fixed rate of heating. Curie temperatures are distributed close to 550°C. These properties differ markedly from those of common submarine basalts observed before. X-ray microprobe analysis techniques were used to determine internal structures of ferromagnetic minerals; in most of ferromagnetic minerals there exist two different types of magnetic phases (i.e., products of high-temperature and low-temperature oxidations). Interpretations on the coexisting, seemingly contradictory, phases can be made based upon present analyses.

Desarrollo preliminar de descriptores para el análisis sensorial de ajos desecados y liofilizados

El polvo de ajo (Allium sativum L.) es una alternativa para conservar en el tiempo sus propiedades sensoriales y prolongar su vida útil como alimento procesado. En la actualidad, no existe una definición clara de las propiedades sensoriales que caracterizan el ajo ni de las técnicas más adecuadas para su análisis. Los objetivos del presente trabajo fueron estudiar diferentes vehículos y determinar el más apropiado para el análisis sensorial del polvo de ajo, y generar y definir los descriptores para las propiedades sensoriales de olor y flavor de diferentes cultivares deshidratados a través de dos métodos: en estufa a 50°C y por liofilización a -50°C, bajo vacío. Se pretende contribuir a la caracterización de este producto aportando un vocabulario específico y sus definiciones, como así también una metodología sensorial propia. Ocho evaluadores, seleccionados y entrenados de acuerdo con las normas internacionales y con experiencia en análisis sensorial, probaron diferentes vehículos y una vez determinado el más adecuado, desarrollaron el lenguaje descriptivo para los ajos desecados y liofilizados seleccionando por consenso los descriptores que mejor caracterizaban las cultivares, y se definió cada término. Se generaron 31 descriptores simples. Si bien, algunos de los descriptores coincidieron con los publicados en la guía ASTM DS 66 (1996) para ajos frescos, con esta investigación se aportó un amplio número de términos nuevos para la descripción del olor y el flavor de los ajos desecados y liofilizados, los cuales contribuyen a una mejor caracterización sensorial de este producto.

Análisis de co-términos y de redes sociales para la generación de mapas temáticos

La mejora de las capacidades de búsqueda y de las interfaces de los opacs sigue siendo uno de los principales desafíos para las bibliotecas, especialmente en lo que respecta al acceso por materias. Las interfaces visuales pueden facilitar la recuperación. El objetivo del presente trabajo es explorar si la combinación de técnicas de análisis de co-términos y de redes sociales resulta ser una metodología válida para la generación de mapas temáticos de la colección. La principal conclusión es que el método es válido, y que los mapas obtenidos podrían servir como interfaz visual para el acceso por materias. También es útil para detectar problemas en los criterios de indización y contribuir a la mejora de la calidad de la descripción temática del conjunto documental

Territorios y mercados globales: Las firmas agroexportadoras citrícolas del noreste argentino

El trabajo aborda la problemática de las firmas empacadoras/exportadoras de cítricos dulces del denominado corredor citrícola del río Uruguay -departamentos de Federación y Concordia en la provincia de Entre Ríos y departamento de Monte Caseros en Corrientes-. Específicamente nos preguntamos si la convergencia geográfica de firmas en un mismo espacio regional/local propicia mecanismos de articulación que favorezcan la obtención de sinergias y su participación en el segmento exportador, considerándolas en relación al capital trasnacional que opera en la misma región. En nuestro análisis exploramos algunas de las estrategias que adoptan las firmas para la inserción en los mercados, enfocándonos en los mecanismos de coordinación interempresarial a nivel horizontal y a escala local-regional, prestando particular atención a la sustentabilidad de los mismos. Empleamos un enfoque metodológico que pone énfasis en técnicas de análisis cualitativas, aplicadas a entrevistas semi-estructuradas y en profundidad a los integrantes de la trama, seleccionados en función del rol que cumplen dentro de ella. La información relevada se complementa con datos secundarios y la revisión de bibliografía pertinente para el área de estudio.

Análisis de co-términos y de redes sociales para la generación de mapas temáticos

La mejora de las capacidades de búsqueda y de las interfaces de los opacs sigue siendo uno de los principales desafíos para las bibliotecas, especialmente en lo que respecta al acceso por materias. Las interfaces visuales pueden facilitar la recuperación. El objetivo del presente trabajo es explorar si la combinación de técnicas de análisis de co-términos y de redes sociales resulta ser una metodología válida para la generación de mapas temáticos de la colección. La principal conclusión es que el método es válido, y que los mapas obtenidos podrían servir como interfaz visual para el acceso por materias. También es útil para detectar problemas en los criterios de indización y contribuir a la mejora de la calidad de la descripción temática del conjunto documental

Territorios y mercados globales: Las firmas agroexportadoras citrícolas del noreste argentino

El trabajo aborda la problemática de las firmas empacadoras/exportadoras de cítricos dulces del denominado corredor citrícola del río Uruguay -departamentos de Federación y Concordia en la provincia de Entre Ríos y departamento de Monte Caseros en Corrientes-. Específicamente nos preguntamos si la convergencia geográfica de firmas en un mismo espacio regional/local propicia mecanismos de articulación que favorezcan la obtención de sinergias y su participación en el segmento exportador, considerándolas en relación al capital trasnacional que opera en la misma región. En nuestro análisis exploramos algunas de las estrategias que adoptan las firmas para la inserción en los mercados, enfocándonos en los mecanismos de coordinación interempresarial a nivel horizontal y a escala local-regional, prestando particular atención a la sustentabilidad de los mismos. Empleamos un enfoque metodológico que pone énfasis en técnicas de análisis cualitativas, aplicadas a entrevistas semi-estructuradas y en profundidad a los integrantes de la trama, seleccionados en función del rol que cumplen dentro de ella. La información relevada se complementa con datos secundarios y la revisión de bibliografía pertinente para el área de estudio.

Análisis de co-términos y de redes sociales para la generación de mapas temáticos

La mejora de las capacidades de búsqueda y de las interfaces de los opacs sigue siendo uno de los principales desafíos para las bibliotecas, especialmente en lo que respecta al acceso por materias. Las interfaces visuales pueden facilitar la recuperación. El objetivo del presente trabajo es explorar si la combinación de técnicas de análisis de co-términos y de redes sociales resulta ser una metodología válida para la generación de mapas temáticos de la colección. La principal conclusión es que el método es válido, y que los mapas obtenidos podrían servir como interfaz visual para el acceso por materias. También es útil para detectar problemas en los criterios de indización y contribuir a la mejora de la calidad de la descripción temática del conjunto documental

Territorios y mercados globales: Las firmas agroexportadoras citrícolas del noreste argentino

El trabajo aborda la problemática de las firmas empacadoras/exportadoras de cítricos dulces del denominado corredor citrícola del río Uruguay -departamentos de Federación y Concordia en la provincia de Entre Ríos y departamento de Monte Caseros en Corrientes-. Específicamente nos preguntamos si la convergencia geográfica de firmas en un mismo espacio regional/local propicia mecanismos de articulación que favorezcan la obtención de sinergias y su participación en el segmento exportador, considerándolas en relación al capital trasnacional que opera en la misma región. En nuestro análisis exploramos algunas de las estrategias que adoptan las firmas para la inserción en los mercados, enfocándonos en los mecanismos de coordinación interempresarial a nivel horizontal y a escala local-regional, prestando particular atención a la sustentabilidad de los mismos. Empleamos un enfoque metodológico que pone énfasis en técnicas de análisis cualitativas, aplicadas a entrevistas semi-estructuradas y en profundidad a los integrantes de la trama, seleccionados en función del rol que cumplen dentro de ella. La información relevada se complementa con datos secundarios y la revisión de bibliografía pertinente para el área de estudio.

30 years of synoptic observations from Neumayer Station with links to datasets

The analysis of research data plays a key role in data-driven areas of science. Varieties of mixed research data sets exist and scientists aim to derive or validate hypotheses to find undiscovered knowledge. Many analysis techniques identify relations of an entire dataset only. This may level the characteristic behavior of different subgroups in the data. Like automatic subspace clustering, we aim at identifying interesting subgroups and attribute sets. We present a visual-interactive system that supports scientists to explore interesting relations between aggregated bins of multivariate attributes in mixed data sets. The abstraction of data to bins enables the application of statistical dependency tests as the measure of interestingness. An overview matrix view shows all attributes, ranked with respect to the interestingness of bins. Complementary, a node-link view reveals multivariate bin relations by positioning dependent bins close to each other. The system supports information drill-down based on both expert knowledge and algorithmic support. Finally, visual-interactive subset clustering assigns multivariate bin relations to groups. A list-based cluster result representation enables the scientist to communicate multivariate findings at a glance. We demonstrate the applicability of the system with two case studies from the earth observation domain and the prostate cancer research domain. In both cases, the system enabled us to identify the most interesting multivariate bin relations, to validate already published results, and, moreover, to discover unexpected relations.

Stable carbon and oxygen isotope record of IODP Site 306-U1313, MIS 23-19

Since the seminal work by Hays et al. (1976), a plethora of studies has demonstrated a correlation between orbital variations and climatic change. However, information on how changes in orbital boundary conditions affected the frequency and amplitude of millennial-scale climate variability is still fragmentary. The Marine Isotope Stage (MIS) 19, an interglacial centred at around 785 ka, provides an opportunity to pursue this question and test the hypothesis that the long-term processes set up the boundary conditions within which the short-term processes operate. Similarly to the current interglacial, MIS 19 is characterised by a minimum of the 400-kyr eccentricity cycle, subdued amplitude of precessional changes, and small amplitude variations in insolation. Here we examine the record of climatic conditions during MIS 19 using high-resolution stable isotope records from benthic and planktonic foraminifera from a sedimentary sequence in the North Atlantic (Integrated Ocean Drilling Program Expedition 306, Site U1313) in order to assess the stability and duration of this interglacial, and evaluate the climate system's response in the millennial band to known orbitally induced insolation changes. Benthic and planktonic foraminiferal d18O values indicate relatively stable conditions during the peak warmth of MIS 19, but sea-surface and deep-water reconstructions start diverging during the transition towards the glacial MIS 18, when large, cold excursions disrupt the surface waters whereas low amplitude millennial scale fluctuations persist in the deep waters as recorded by the oxygen isotope signal. The glacial inception occurred at ~779 ka, in agreement with an increased abundance of tetra-unsaturated alkenones, reflecting the influence of icebergs and associated meltwater pulses and high-latitude waters at the study site. After having combined the new results with previous data from the same site, and using a variety of time series analysis techniques, we evaluate the evolution of millennial climate variability in response to changing orbital boundary conditions during the Early-Middle Pleistocene. Suborbital variability in both surface- and deep-water records is mainly concentrated at a period of ~11 kyr and, additionally, at ~5.8 and ~3.9 kyr in the deep ocean; these periods are equal to harmonics of precession band oscillations. The fact that the response at the 11 kyr period increased over the same interval during which the amplitude of the response to the precessional cycle increased supports the notion that most of the variance in the 11 kyr band in the sedimentary record is nonlinearly transferred from precession band oscillations. Considering that these periodicities are important features in the equatorial and intertropical insolation, these observations are in line with the view that the low-latitude regions play an important role in the response of the climate system to the astronomical forcing. We conclude that the effect of the orbitally induced insolation is of fundamental importance in regulating the timing and amplitude of millennial scale climate variability.

Assessment of CTF boiling transition and critical heat flux modeling capabilities using the OECD/NRC BFBT and PSBT benchmark databases

The need to refine models for best-estimate calculations, based on good-quality experimental data, has been expressed in many recent meetings in the field of nuclear applications. The modeling needs arising in this respect should not be limited to the currently available macroscopic methods but should be extended to next-generation analysis techniques that focus on more microscopic processes. One of the most valuable databases identified for the thermalhydraulics modeling was developed by the Nuclear Power Engineering Corporation (NUPEC), Japan. From 1987 to 1995, NUPEC performed steady-state and transient critical power and departure from nucleate boiling (DNB) test series based on the equivalent full-size mock-ups. Considering the reliability not only of the measured data, but also other relevant parameters such as the system pressure, inlet sub-cooling and rod surface temperature, these test series supplied the first substantial database for the development of truly mechanistic and consistent models for boiling transition and critical heat flux. Over the last few years the Pennsylvania State University (PSU) under the sponsorship of the U.S. Nuclear Regulatory Commission (NRC) has prepared, organized, conducted and summarized the OECD/NRC Full-size Fine-mesh Bundle Tests (BFBT) Benchmark. The international benchmark activities have been conducted in cooperation with the Nuclear Energy Agency/Organization for Economic Co-operation and Development (NEA/OECD) and Japan Nuclear Energy Safety (JNES) organization, Japan. Consequently, the JNES has made available the Boiling Water Reactor (BWR) NUPEC database for the purposes of the benchmark. Based on the success of the OECD/NRC BFBT benchmark the JNES has decided to release also the data based on the NUPEC Pressurized Water Reactor (PWR) subchannel and bundle tests for another follow-up international benchmark entitled OECD/NRC PWR Subchannel and Bundle Tests (PSBT) benchmark. This paper presents an application of the joint Penn State University/Technical University of Madrid (UPM) version of the well-known subchannel code COBRA-TF, namely CTF, to the critical power and departure from nucleate boiling (DNB) exercises of the OECD/NRC BFBT and PSBT benchmarks

Performance Comparison Between Serrated Edge and Rolled Edge Reflectors Inside CATR Facilities

CATR facilities are attractive antenna measurement facilities. Main reasons which contribute to this fact lie on its inherent reduced volume, on-the-fly measurements and the extension of both to a wide range of frequencies. However, these features rely on the assumption that the field collimation scheme is able to generate a plane wave distribution (quiet zone) where the AUT is to be placed and operated in RX mode. Unfortunately, electromagnetic theory states that this field distribution is not possible to be generated by a finite size scatterer operated as the collimator of a nonzero wavelength time-harmonic propagating field. This is the background of this paper, where two well-known electromagnetic field collimators will be discussed: the serrated edge reflector and the blended rolled edge reflector. To reach this purpose, electromagnetic hybrid analysis techniques developed at Technical University of Madrid will be applied.

A modelling language for the resilience assessment of networked systems of systems

Systems of Systems (SoS) present challenging features and existing tools result often inadequate for their analysis, especially for heteregeneous networked infrastructures. Most accident scenarios in networked systems cannot be addressed by a simplistic black or white (i.e. functioning or failed) approach. Slow deviations from nominal operation conditions may cause degraded behaviours that suddenly end up into unexpected malfunctioning, with large portions of the network affected. In this paper,we present a language for modelling networked SoS. The language makes it possible to represent interdependencies of various natures, e.g. technical, organizational and human. The representation of interdependencies is based on control relationships that exchange physical quantities and related information. The language also makes it possible the identification of accident scenarios, by representing the propagation of failure events throughout the network. The results can be used for assessing the effectiveness of those mechanisms and measures that contribute to the overall resilience, both in qualitative and quantitative terms. The presented modelling methodology is general enough to be applied in combination with already existing system analysis techniques, such as risk assessment, dependability and performance evaluation