On the Lengths, Colours and Ages of Bars

In an effort to obtain further observational evidences for secular evolution processes in galaxies, as well as observational constraints to current theoretical models of secular evolution, we have used BVRI and Ks images of a sample of 18 barred galaxies to measure the lengths and colours of bars, create colour maps and estimate global colour gradients. In addition, applying a method we developed in a previous article, we could distinguish for 7 galaxies in our sample those whose bars have been recently formed from the ones with already evolved bars. We estimated an average difference in the optical colours between young and evolved bars that may be translated to an age difference of the order of 10 Gyr, meaning that bars may be long standing structures. Moreover, our results show that, on average, evolved bars are longer than young bars. This seems to indicate that, during its evolution, a bar grows longer by capturing stars from the disk, in agreement with recent numerical and analytical results.Comment: To appear in Galaxy Evolution Across the Hubble Time, proceedings of the IAU Symp. 235, F. Combes and J. Palous (eds.); 1 page; the poster can be found at http://www.mpa-garching.mpg.de/~dimitri/iauga.pd

El dolor de espalda como lesión deportiva en jóvenes de 10-12 años

El objetivo de esta investigación es analizar la incidencia de dolor de espalda en jóvenes de entre 10 y 12 años en función de si practican o no algún deporte, cuál practican, con qué frecuencia, y las posibles diferencias entre género. El estudio se llevó a cabo en 2270 escolares (1214 niños y 1056 niñas) de 10-12 años de Mallorca. La muestra se obtuvo por conglomerados (centros escolares) por muestreo intencional. El cuestionario y la metodología de recogida de datos fueron previamente validados mediante el método test-retest. Los resultados obtenidos muestran que la existencia de dolor de espalda fue del 38.3% (34.5% en niños y 42.8% en niñas). Existe una relación significativa entre dolor de espalda y practicar deporte o no, en niños positiva y en niñas negativa, pudiendo ser explicado por las diferencias del tipo de deportes practicados según el género. Los mayores índices de incidencia de dolor de espalda aparecen entre los que practican voleibol, gimnasia deportiva y natación más de 4 horas semanales, y los que practican gimnasia rítmica. Este estudio sugiere, a partir de los resultados obtenidos, que el dolor de espalda es un mal que afecta de manera importante a la población juvenil, en especial al género femenino, y que el tipo de deporte practicado, así como su frecuencia, es determinante a la hora de definir si un deporte puede ser o no un factor de riesgo asociado al dolor de espalda.The aim of this research study is to explore the existence of back pain in schoolchildren aged 10-12 years old related to sports practice or not, sports type, frequency, and gender differences. This study was carried out using a sample of 2270 schoolchildren (1214 boys and 1056 girls) aged 10-12, resident in Mallorca. The sample was chosen using intentional random sampling. The questionnaire and method for gathering the data were previously validated using the test-rest reliability method. The results show the existence of low back pain among 38.3% of the schoolchildren (34.5% boys and 42.8% girls) suffers from back pain. There is a significant relationship between back pain and sport practice, positively in boys and negativity in girls, being explicated for the different sports practice according to gender. The highest values of back pain incidence were found in volleyball, masculine gymnastics and swimming more the 4 hours per week, and in rhythmic gymnastics. This study suggests, according to the results, back pain as a problem that affects the young population, especially to girls. The type of sport and its frequency is determinant to define if a sport could be or not a risk factor related to low back pain.O objectivo desta investigação foi analisar a incidência da dor cervical em jovens com idades compreendidas entre os 10 e os 12 anos em função de praticarem ou não algum desporto, qual praticam, com que frequência, e as possíveis diferenças de género. O estudo foi levado a cabo em 2270 alunos (1214 rapazes e 1056 raparigas) de 10-12 anos de Maiorca. A amostra foi composta por conglomerados (centros escolares) por amostragem de conveniência. O questionário e a metodologia de recolha de dados foram previamente validados mediante o método de teste-reteste. Os resultados obtidos mostram que a existência de dor cervical foi de 28.3% (34.5% em rapazes e 42.8% em raparigas). Existe uma relação significativa entre a dor cervical e praticar ou não desporto, positiva em rapazes e negativa em raparigas, podendo isto ser explicado pelas diferenças no tipo de modalidades praticadas segundo o género. Os maiores índices de incidência de dor cervical registam-se entre os que praticam voleibol, ginástica desportiva e natação mais de 4 horas semanais, e os que praticam ginástica rítmica. Este estudo sugere, a partir dos resultados obtidos, que a dor cervical é um mal que afecta de forma importante a população juvenil, em particular o género feminino, e que o tipo de modalidade praticada, assim como a sua frequência, é determinante quando se define se um desporto pode ou não ser um factor de risco associado à dor cervical

Intereses, motivos y actitudes hacia el deporte en adolescentes : diferencias en función del nivel de práctica

El trabajo que se presenta forma parte de un estudio descriptivo más amplio en el que se analizan los hábitos, motivos, intereses y actitudes hacia el deporte en una muestra de adolescentes, estudiantes de 2º ciclo de E.S.O. Concretamente se analizan diferentes variables en función de la frecuencia e intensidad de la práctica deportiva en jóvenes practicantes. Se estudió una muestra representativa de la población mencionada compuesta por 1999 sujetos. El instrumento utilizado fue un cuestionario de elaboración propia y los resultados muestran que el nivel de práctica deportiva (bajo, medio, alto) establece diferencias en relación a motivos, actitudes y en definitiva patrones de actividad deportiva.The present analysis is part of a broader descriptive study that assess habits, motives, interests and attitudes toward sport practice in a sample of adolescents that study 2nd ESO. We analyse different variables in relation to frequency and levels of practice in young sport participants. We studied a representative sample of the population analysed (N=1999 subjects). We designed an instrument that includes the different variables. Results show that the level of sport practice (low, medium, high) implies significant differences in relation to motives attitudes and patterns of physical activity

Perfil de hábitos deportivos de los preadolescentes de la isla de Mallorca

La práctica deportiva constituye una de las actividades de ocio preferidas por toda la población, pero los deportistas no forman en ningún momento un grupo homogéneo, atendiendo a que existen claras diferencies en función del género y de los factores sociodemográficos. Mientras que la etapa escolar coincide con el momento de máxima participación en actividades físicas y deportivas, la salida de la escuela coincide con el abandono masivo de esta práctica, a causa de la multiplicidad de factores que dependen de variables psicológicas y variables sociopersonales. El objetivo del artículo que a continuación se presenta, es identificar el perfil del deportista de la Isla de Mallorca en función de variables sociodemográficas y del nivel de práctica. Este trabajo forma parte de una amplia investigación realizada durante el ano 2001 que pretendía estudiar e identificar los hábitos de práctica deportiva de la población mallorquina de entre 10 y 14 anos. Para realizar dicho estudio se utilizó una muestra de 2661 personas y para la evaluación se utilizó un cuestionario de elaboración propia previamente validado y basado en otros autores. Los resultados obtenidos con este estudio, sugieren que la práctica deportiva se ha consolidado como estilo de vida en nuestra sociedad y ocupa un lugar preferente en el tiempo de ocio entre los preadolescentes mallorquines. Asimismo son resaltables las diferencias claramente significativas existentes entre hombres y mujeres de las edades motivo de estudio en cuanto a práctica deportiva fuera de las clases de Educación Física.Participating in sports is one of people's favourite leisure time activities, but athletes are not a homogeneous group at any time, owing to obvious differences in gender and socio-demographic factors. Maximum participation in physical and sport activities occurs during a child's school years. On the other hand, participation in sports drops massively when children leave school, owing to a multitude of factors that depend on psychological and socio-personal factors. The objective of this article is to identify the athletic profile of people from the island of Majorca in accordance with sociodemographic variables and levels of participation. This paper is part of research conducted during 2001 that aimed to study and identify the athletic habits of the Majorcan population between 10 and 14 years of age. A sample of 2661 subjects was studied and a previously validated questionnaire based on authors' work was used for evaluation. The results obtained in this study demonstrate that taking part in sports has been consolidated as a life style in our society and that it is a favourite occupation for Majorcan pre-adolescents during free time. It is also significant to emphasize the obvious differences between males and females in the age groups studied in connection with taking part in sports outside physical education classes

Relaciones entre calidad de vida, actividad física, sedentarismo y fitness cardiorrespiratorio en niños

The aim of this study was to explore the relationship between some domains of health related quality of life (HRQoL) in children with cardiorespiratory fitness, physical activity level, sedentary lifestyle (screen time) and the body mass index of a population of 302 children eleven and twelve years of age to determine whether physical fitness (cardiorespiratory fitness) is a key factor, to ensure the future quality of life of children. Children's health and Illness profile - Child edition - Parent Report Form - Spanish Edition - (CHIP-CE / PRF-Spanish edition) was used to measure HRQoL, the 20m run test for cardiorespiratory fitness, and the School Health Action, Planning and Evaluation (SHAPES) physical activity module was used to measure weekly physical activity and screen time. Parents reported height and weight. The results show a strong correlation between cardiorespiratory fitness and HRQoL, and screen time with HRQoL, but no correlation between HRQoL and physical activity

Well-to-wheels analysis of fast pyrolysis pathways with the GREET model.

The pyrolysis of biomass can help produce liquid transportation fuels with properties similar to those of petroleum gasoline and diesel fuel. Argonne National Laboratory conducted a life-cycle (i.e., well-to-wheels [WTW]) analysis of various pyrolysis pathways by expanding and employing the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The WTW energy use and greenhouse gas (GHG) emissions from the pyrolysis pathways were compared with those from the baseline petroleum gasoline and diesel pathways. Various pyrolysis pathway scenarios with a wide variety of possible hydrogen sources, liquid fuel yields, and co-product application and treatment methods were considered. At one extreme, when hydrogen is produced from natural gas and when bio-char is used for process energy needs, the pyrolysis-based liquid fuel yield is high (32% of the dry mass of biomass input). The reductions in WTW fossil energy use and GHG emissions relative to those that occur when baseline petroleum fuels are used, however, is modest, at 50% and 51%, respectively, on a per unit of fuel energy basis. At the other extreme, when hydrogen is produced internally via reforming of pyrolysis oil and when bio-char is sequestered in soil applications, the pyrolysis-based liquid fuel yield is low (15% of the dry mass of biomass input), but the reductions in WTW fossil energy use and GHG emissions are large, at 79% and 96%, respectively, relative to those that occur when baseline petroleum fuels are used. The petroleum energy use in all scenarios was restricted to biomass collection and transportation activities, which resulted in a reduction in WTW petroleum energy use of 92-95% relative to that found when baseline petroleum fuels are used. Internal hydrogen production (i.e., via reforming of pyrolysis oil) significantly reduces fossil fuel use and GHG emissions because the hydrogen from fuel gas or pyrolysis oil (renewable sources) displaces that from fossil fuel natural gas and the amount of fossil natural gas used for hydrogen production is reduced; however, internal hydrogen production also reduces the potential petroleum energy savings (per unit of biomass input basis) because the fuel yield declines dramatically. Typically, a process that has a greater liquid fuel yield results in larger petroleum savings per unit of biomass input but a smaller reduction in life-cycle GHG emissions. Sequestration of the large amount of bio-char co-product (e.g., in soil applications) provides a significant carbon dioxide credit, while electricity generation from bio-char combustion provides a large energy credit. The WTW energy and GHG emissions benefits observed when a pyrolysis oil refinery was integrated with a pyrolysis reactor were small when compared with those that occur when pyrolysis oil is distributed to a distant refinery, since the activities associated with transporting the oil between the pyrolysis reactors and refineries have a smaller energy and emissions footprint than do other activities in the pyrolysis pathway