Longitudinal study of physical activity in college students: Testing self-determination theory based on stages of change

The main purpose of this study was to longitudinally test the relationships of Self Determination Theory variables on physical activity, analyzing the model based on stages of change. The study is a longitudinal and quantitative research. We have developed a longitudinal cross-lagged design for structural equation models of three time points and multi-group analysis. Participants were 772 Spanish college students from the University of Zaragoza (M = 19.74, SD = 2.76) studying several degrees. Participants completed different self-reports, assessing: physical activity, stages of change, motivation and basic psychological needs, at three time points (November, January and March). The analysis indicated that intrinsic motivation positively predicted physical activity at the 3-time points, both directly and indirectly. Intrinsic motivation was negatively predicted by autonomy and positively predicted by competence (from time point 2 to 3). No relationships were found with relatedness for the entire sample. Regarding the stages of change multi-group analysis were run: in the low active group, we found a negative relationship between relatedness and physical activity, and a positive association between competence and intrinsic motivation and physical activity, whereas intrinsic motivation did not predict physical activity. Our findings showed that intrinsic motivation was the most consistent predictor of physical activity. The competence need played an essential role in intrinsic motivation and physical activity for both active and passive subjects. However, the basic psychological needs have not worked as indicated by the theory when it was examined longitudinally. The findings of the study highlight the need for different strategies to improve physical activity levels according to the stages of change

First insights on Lake General Carrera/Buenos Aires/Chelenko water balance

Lago General Carrera (Chile) also called Lago Buenos Aires (Argentina) or originally Chelenko by the native habitants of the region is located in Patagonia on the Chilean-Argentinean border. It is the largest lake in Chile with a surface area of 1850 km<sup>2</sup>. The lake is of glacial/tectonic origin and surrounded by the Andes mountain range. The lake drains primarily to the Pacific Ocean to the west, through the Baker River (one of Chile's largest rivers), and intermittently eastward to the Atlantic Ocean. We report ongoing results from an investigation of the seasonal hydrological cycle of the lake basin. The contribution by river input through snowmelt from the Andes is of primary importance, though the lack of water input by ungaged rivers is also critical. We present the main variables involved in the water balance of Lake General Carrera/Buenos Aires/Chelenko, such as influent and effluent river flows, precipitation, and evaporation, all this based mostly in in-situ information

Evaluación financiera de producción de pejelagarto (atractosteus tropicus): Caso cooperativa de producción pesquera acuícola "El pejelagarto", S.C. de R.L.

Se evalúo la rentabilidad de la producción de pejelagarto (Atractosteus tropicus) en dos modalidades de cultivo, en condiciones de cautiverio y en cautiverio en asociación con la mojarra castarrica y tilapia en la Sociedad Cooperativa de Producción Acuícola "El Pejelagarto", localizada en Sabancuy, municipio de Carmen, Campeche, México. Para tal efecto, se utilizaron los registros de 10 años para el cálculo de los indicadores de evaluación económica siguientes para el primer modo de cultivo: valor actual neto (VAN), relación beneficio-costo (B/C), relación beneficio-inversión neta (K/N) y la tasa interna de retorno (TIR). Los resultados obtenidos, para este período, fueron: VAN = 119,825.00, B/C = 1.08, N/K = 1.88 y TIR = 25.6%. Los indicadores para el cultivo en asociación fueron VAN = 629,254, B/C = 1.43, N/K = 10.15 y TIR = 145.0%. Con base en los resultados de los indicadores, se concluye que el proyecto productivo es viable en sus dos modalidades de cultivo, desde el punto de vista económico; por lo anterior, la cría, producción y comercialización de pejelagarto, tiene una gran oportunidad de negocio, por ser una especie con demanda, dentro y fuera de la región, por su rusticidad en la cría además de ser considerado un platillo exótico

Evaluación económica de la producción de mojarra castarrica en palizada, Campeche, México

El presente trabajo de investigación se realizó en la organización de productores denominada Producción pesquera y acuícola de bienes y servicios acuacultores de la Rivera Alta S.C. de R.L. de C.V. en Palizada, Campeche, México; el cual tiene como propósito determinar la rentabilidad del proyecto de inversión de mojarra castarrica para informar si los recursos que se invirtieron han permitido capitalizar a los miembros de la Sociedad Cooperativa. Por lo anterior, se calcularon los indicadores de rentabilidad que se establecen en la metodología para la formulación y evaluación de proyectos de inversión para medir la rentabilidad de la organización de productores, los cuales son: Valor Actual Neto (VAN), Relación Beneficio Costo (B/C), Relación Beneficio-Inversión Neta (N/K) y la Tasa Interna de Retorno (TIR). Los resultados obtenidos en un periodo de análisis de 10 años son: VAN = 563,743; B/C = 1.34; N/K = 8.79 y la TIR = 141.6%. Al efectuarse el análisis de sensibilidad a la estructura de ingresos y costos totales se observó que el proyecto puede sufrir una disminución de los ingresos de alrededor de 20% siendo rentable y por el lado de los costos totales puede tener un aumento de alrededor de 20% y muestra redituabilidad

Determination of pulsation periods and other parameters of 2875 stars classified as MIRA in the All Sky Automated Survey (ASAS)

We have developed an interactive PYTHON code and derived crucial ephemeris data of 99.4% of all stars classified as 'Mira' in the ASAS data base, referring to pulsation periods, mean maximum magnitudes and, whenever possible, the amplitudes among others. We present a statistical comparison between our results and those given by the AAVSO International Variable Star Index (VSX), as well as those determined with the machine learning automatic procedure of Richards et al. 2012. Our periods are in good agreement with those of the VSX in more than 95% of the stars. However, when comparing our periods with those of Richards et al, the coincidence rate is only 76% and most of the remaining cases refer to aliases. We conclude that automatic codes require still more refinements in order to provide reliable period values. Period distributions of the target stars show three local maxima around 215, 275 and 330 d, apparently of universal validity, their relative strength seems to depend on galactic longitude. Our visual amplitude distribution turns out to be bimodal, however 1/3 of the targets have rather small amplitudes (A $<$ 2.5$^{m}$) and could refer to semi-regular variables (SR). We estimate that about 20% of our targets belong to the SR class. We also provide a list of 63 candidates for period variations and a sample of 35 multiperiodic stars which seem to confirm the universal validity of typical sequences in the double period and in the Petersen diagramsComment: 14 pages, 14 figures, and 8 tables. Accepted to The Astrophysical Journal Supplement Series, September 201

Root morphology of mandibular molars: a cone-beam computed tomography study

Background: The aim of the study was to assess the number and anatomical classification of roots and root canals of first and second mandibular molars using cone-beam computed tomography (CBCT) in a Chilean population. Materials and methods: This study evaluated the CBCT scans of 289 patients aged between 14 and 86 years, obtaining a sample of 1022 mandibular first and second molars. The number of roots and root canals was evaluated according to the anatomical classification proposed by Ahmed in 2016. Data were analysed using Pearson’s chi-squared test and ANOVA. Results: Nine hundred fifty-one (93.05%) molars had two roots, while the remaining 71 (6.95%) molars had one root. The most frequent root and root canal morphologies found were: 2MM M2 D1 (29.65%),  2MM M2-1 D1 (22.3%) and 2MM M1 D1 (13.4%) (M — mesial, D — distal), with a total of 32 different anatomical distributions. C-shaped canals were present in 56 molars and were more frequently found in women than in men (7.1% vs. 3.88%; p = 0.024). Conclusions: The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals. The most frequent morphology found in mandibular molars in a Chilean population was two roots and three canals

Effect of Threonine and the Bioactive Component of Saccharomyces Cerevisiae on the Productive Performance of the Broiler Cobb 500

This study was conducted in Chimborazo province, Riobamba Canton to evaluate the effect of threonine and the bioactive component of Saccharomyces cerevisiae on the productive performance of the broiler Cobb 500. A total of 270 one-day-old broiler chicken of both sexes were included, which corresponded to an experimental unit size of 15 birds. Two growth promoters were used for the treatments -- T1: Threonine (aminoacid) 200 g/Tn; and T2: bioactive oligosaccharides, obtained from the cell wall of selected strains of S. Cerevisiae (probiotic) 750 g/Tn. These were compared to a control group. The data were analyzed through Analysis of Variance (ADEVA). The separation of means was performed using the Tukey statistic at a level of significance of p &lt; 0.05 and p &lt; 0.01. The data were processed using the Infostat software version 2010. The results showed that the best productive yields were with treatment 2; the values for this treatment were: weight at 28 days: 1369.42 g; weight gain at 28 days: 48.90 g; food conversion at 28 days: 1.39 points; carcass weight: 2527.05 g; and yield to the carcass: 83.85%. Through the economic analysis, it was determined that the highest cost-benefit index was 1.30 USD with the application of T2. So according to the results, a better use of the nutrients that are present in the feed is achieved when bioactive components of S. cerevisiae are supplied in the diet of broiler chickens. Keywords: Threonine, Saccharomyces cerevisiae, productive performance, broiler, Cobb 500. RESUMEN Se realizó un experimento en la provincia de Chimborazo, Cantón Riobamba, para evaluar los efectos de treonina y componentes bioactivos de Saccharomyces cerevisiae sobre el comportamiento productivo en aves Cobb 500. Se utilizaron 270 pollitos mixtos Cobb 500 de un día de edad de ambos sexos, con un tamaño de unidad experimental de 15 aves. Para los tratamientos se manejaron dos promotores de crecimiento, T1: Treonina (aminoácido) 200 g/Tn y T2: Oligosacáridos bioactivos, obtenidos a partir de la pared celular de cepas seleccionadas de S. Cerevisiae750 g/Tn; frente a un testigo (T0). Los datos obtenidos fueron sometidos a Análisis de Varianza (ADEVA); la separación de medias se realizó mediante el estadístico Tukey a un nivel de significancia (p &lt; 0,05) y (p &lt; 0,01); los datos se procesaron mediante el software Infostat versión 2010. Los resultados muestran los mejores rendimientos productivos con el Tratamiento 2, para los parámetros: peso a los 28 días 1369,42 g; ganancia de peso a los 28 días 48,90 g; y conversión alimenticia a los 28 días con 1,39 puntos; así como peso a la canal 2527,05 g; y rendimiento a la canal 83,85%. Mediante el análisis económico se determinó que el mayor índice beneficio costo fue de 1,30 USD con la aplicación del T2. Lo que brinda un indicativo que mediante el suministro de componentes bioactivos de S. cerevisiae en la dieta de pollos broiler, se logra un mejor aprovechamiento de los nutrientes que se encuentran presentes en el alimento, lo que se refleja en los parámetros productivos. Palabras clave: treonina, Saccharomyces cerevisiae, comportamiento productivo, broilers, Cobb 500