Actividad física, ejercicio y deporte en la lucha contra la obesidad infantil y juvenil

El propósito del presente documento es proponer desde el grupo de expertos en ejercicio físico y salud de EXERNET (Red Española de Investigación en Ejercicio Físico y Salud) una serie de recomendaciones sobre la práctica de la actividad física y deportiva que a nivel individual, familiar e institucional ayuden a prevenir y tratar la obesidad infantil y juvenil, basadas en la evidencia científi ca actual

Modelos de crecimiento y producción de selvicultura para Pinus halepensis Mill.

Growth and yield models of silviculture applied to four site indices have been drawn up. The data were obtained in 72 plots, installed in 1965 in man made stands of Pinus halepensis Mill., and inventoried in 1965, 1975, 1980, 1988 y 1999. The site index was defined as the top height at age 80 and models were adjusted using the Richards function, obtaining four site qualities: 20, 17, 14 and 11. Following this, silvicultural production models, including two different thinning regimes, were developed for the two higher site qualities sites, with more productive interest (20 and 17) using a simulation with the Hart-Becking rate. For 11 and 14 site quality, only one moderate thinning regime was developed, bearing in mind their most important protection value.A partir de los datos obtenidos de 72 parcelas instaladas en 1965, en masas repobladas de Pinus halepensis, inventariadas en 1965, 1970, 1975, 1980, 1988 y 1999, se han elaborado modelos de crecimiento y producción de selvicultura encontrada para cuatro calidades de estación. Las curvas de calidad se han definido por la altura dominante alcanzada a los 80 años de edad y se han ajustado por el modelo de Richards, resultando las siguientes curvas: calidad 20, calidad 17, calidad 14 y calidad 11. Posteriormente se han elaborado modelos de producción de selvicultura variable incluyendo dos regímenes de claras, simulados a través de la variación del índice de Hart-Becking, para las calidades 20 y 17, que son las que presenta un mayor interés productivo. Para las calidades 14 y 11 se representan tablas con un único régimen moderado de claras, como corresponde a su mayor interés protector y su menor interés productivo

The greater resilience of mixed forests to drought mainly depends on their composition: Analysis along a climate gradient across Europe

Despite growing evidence that diverse forests play an important role in ecosystem functioning, ensuring the provision of different ecosystem services, whether such diversity improves their response to drought events remains unclear. In this study, we use a large tree-ring database from thirty case studies across nine European countries and eleven species, covering from Mediterranean to hemiboreal forests, to test if the growth response to site specific drought events that occurred between 1975 and 2015 varied between mixed and monospecific stands. In particular, we quantify how stands resist those specific drought events and recover after them, thus analyzing their resilience. For each drought event and forest stand we calculated resistance, recovery, resilience and relative resilience and we related the variation in these indices between monospecific and mixed stands with type of admixture, tree species identity, site aridity gradient, stand basal area and stand age. We found a large variability among case studies, even for those that share similar species composition and have similar climates. On average, mixed stands showed higher resistance, resilience and relative resilience to drought events than monospecific stands. However, the beneficial effect of mixtures could not be generalized, being greatly modulated by the type of admixture and tree species identity, and depending on site water supply and stand characteristics, such as basal area and age. The increase in resilience in mixtures compared with monocultures was greater on the conifer-broadleaved admixtures, and to a lesser extent in the broadleaved-broadleaved combinations. The observed response patterns to drought largely varied among the eleven studied species, thus revealing the importance of functional traits for understanding a species’ response to drought across its distribution range. Along the site aridity gradient, resilience and relative resilience to drought increased in drier sites for both monospecific and mixed stands, with an observed trend towards higher resilience in mixed stands in the drier and hotter sites. Our results confirm the complexity of the relationships found of resistance, recovery, resilience and relative resilience with drought when comparing pure vs mixed stands

Physical fitness reference standards for preschool children: The PREFIT project

Objectives. Reference values are necessary for classifying children, for health screening, and for early prevention as many non-communicable diseases aggravate during growth and development. While physical fitness reference standards are available in children aged 6 and older, such information is lacking in preschool children. Therefore, the purposes of this study were (1) to provide sex-and age-specific physical fitness reference standards for Spanish preschool children; and (2) to study sex differences across this age period and to characterise fitness performance throughout the preschool period. Design. Cross-sectional. Methods. A total of 3179 preschool children (1678 boys) aged 2.8–6.4 years old from Spain were included in the present study. Physical fitness was measured using the PREFIT battery. Results. Age- and sex-specific percentiles for the physical fitness components are provided. Boys performed better than girls in the cardiorespiratory fitness, muscular strength, and speed-agility tests over the whole preschool period studied and for the different percentiles. In contrast, girls performed slightly better than boys in the balance test. Older children had better performance in all fitness tests than their younger counterparts. Conclusions. Our study provides age- and sex-specific physical fitness reference standards in preschool children allowing interpretation of fitness assessment. Sexual dimorphism in fitness tests exists already at preschool age, and these differences become larger with age. These findings will help health, sport, and school professionals to identify preschool children with a high/very low fitness level, to examine changes in fitness over time, and to analyse those changes obtained due to intervention effects

The greater resilience of mixed forests to drought mainly depends on their composition: Analysis along a climate gradient across Europe

Despite growing evidence that diverse forests play an important role in ecosystem functioning, ensuring the provision of different ecosystem services, whether such diversity improves their response to drought events remains unclear. In this study, we use a large tree-ring database from thirty case studies across nine European countries and eleven species, covering from Mediterranean to hemiboreal forests, to test if the growth response to site specific drought events that occurred between 1975 and 2015 varied between mixed and monospecific stands. In particular, we quantify how stands resist those specific drought events and recover after them, thus analyzing their resilience. For each drought event and forest stand we calculated resistance, recovery, resilience and relative resilience and we related the variation in these indices between monospecific and mixed stands with type of admixture, tree species identity, site aridity gradient, stand basal area and stand age. We found a large variability among case studies, even for those that share similar species composition and have similar climates. On average, mixed stands showed higher resistance, resilience and relative resilience to drought events than monospecific stands. However, the beneficial effect of mixtures could not be generalized, being greatly modulated by the type of admixture and tree species identity, and depending on site water supply and stand characteristics, such as basal area and age. The increase in resilience in mixtures compared with monocultures was greater on the conifer-broadleaved admixtures, and to a lesser extent in the broadleaved-broadleaved combinations. The observed response patterns to drought largely varied among the eleven studied species, thus revealing the importance of functional traits for understanding a species’ response to drought across its distribution range. Along the site aridity gradient, resilience and relative resilience to drought increased in drier[...]Miškų ir ekologijos fakultetasVytauto Didžiojo universiteta

Cuadernos de pedagogía

A través de relatos biográficos, el grupo de investigación Esbrina se propone reconstruir, conjuntamente con sus protagonistas, el paso de dieciocho jóvenes por la Educación Secundaria Obligatoria. Estas investigaciones sitúan el foco de la investigación en el sujeto y en las relaciones que construye. Forma parte de un dossier titulado “Las relaciones de los jóvenes con el saber”.Madrid (Comunidad Autónoma). Subdirección General de Formación del Profesorado. CRIF Las Acacias; Calle General Ricardos 179; 28025 Madrid; Tel. +34915250893; Fax +34914660991; [email protected]

Stand growth and structure of mixed‑species and monospecific stands of Scots pine (Pinus sylvestris L.) and oak (Q. robur L., Quercus petraea(Matt.) Liebl.) analysed along a productivity gradient through Europe

Past failures of monocultures, caused by wind-throw or insect damages, and ongoing climate change currently strongly stimulate research into mixed-species stands. So far, the focus has mainly been on combinations of species with obvious complementary functional traits. However, for any generalization, a broad overview of the mixing reactions of functionally different tree species in different mixing proportions, patterns and under different site conditions is needed, including assem-blages of species with rather similar demands on resources such as light. Here, we studied the growth of Scots pine and oak in mixed versus monospecific stands on 36 triplets located along a productivity gradient across Europe, reaching from Sweden to Spain and from France to Georgia. The set-up represents a wide variation in precipitation (456–1250 mm year−1), mean annual temperature (6.7–11.5 °C) and drought index by de Martonne (21–63 mm °C−1). Stand inventories and increment cores of trees stemming from 40- to 132-year-old, fully stocked stands on 0.04–0.94-ha-sized plots provided insight into how species mixing modifies stand growth and structure compared with neighbouring monospecific stands. On average, the standing stem volume was 436 and 360 m3 ha−1 in the monocultures of Scots pine and oak, respectively, and 418 m3 ha−1in the mixed stands. The corresponding periodical annual volume increment amounted to 10.5 and 9.1 m3 ha−1 year−1 in the monocultures and 10.5 m3 ha−1 year−1 in the mixed stands. Scots pine showed a 10% larger quadratic mean diameter (p < 0.05), a 7% larger dominant diameter (p < 0.01) and a 9% higher growth of basal area and volume in mixed stands compared with neighbouring monocultures. For Scots pine, the productivity advantages of growing in mixture increased with site index (p < 0.01) and water supply (p < 0.01), while for oak they decreased with site index (p < 0.01). In total, the superior productivity of mixed[...]Miškų ir ekologijos fakultetasVytauto Didžiojo universiteta