Validation of rat brain MR image intensity non-uniformity correction using surface coil images

[Poster] 4th European Molecular Imaging Meeting, Barcelona, Spain, May 27 - 30, 2009Non-uniform intensity artifacts confound the quantitative analysis of magnetic resonance (Mr) images of animal studies, particularly when using surface coils and high-field magnets. The use of correction methods proposed and validated on human brain images such as the n3 algorithm has previously been reported only on mouse images acquired with a volume coil. here, we evaluate the performance of n3 specifically on Mr rat brain images acquired with a surface coilCdTeaM (CeniT-ingenio 2010), Ministerio de Ciencia e innovación, Ciber Cb07/09/0031 CiberSaM, Ministerio de Sanidad y ConsumoPublicad

Predicción de la potencialidad de los bosques esclerófilos españoles mediante redes neuronales artificiales

Holm oak and cork oak forests are between the most important sclerophyllous formations in the Mediterranean Iberia. In order to study their potentiality, an artificial neural network model, with a feedforward BP algorithm, has been applied. The elevation, continentality, insolation, annual rainfall, annual mean temperature, mean temperature of the coldest month and mean temperature of the warmest month are the used bioclimatic variables with a 10 km resolution. The neural networks seem a highly predictive powerful tool. Different patterns in the response of the studied forests have been shown. The holm oak presents a continuous and wide potential simulate range. Meanwhile the cork oak potential area is fragmented and restricted, in accordance with its actual distribution area. The lack of both forests in the eastern and southern warm zones of Iberian Peninsula is the main discrepancy with previous potential vegetation proposals.Encinares y alcornocales son dos de las formaciones esclerófilas más importantes de la Iberia mediterránea. Para conocer cual es su potencialidad en el territorio español se ha empleado un modelo generado mediante redes neuronales artificiales con un algoritmo de retropropagación de errores que conduce la información siempre hacia delante. Las variables bioclimáticas empleadas como predictores son: altitud, continentalidad, insolación, precipitación total, temperatura media anual, temperatura media de las mínimas del mes más frío y temperatura media de las máximas del mes más cálido, con una resolución de 10 km. Las redes neuronales se perfilan como una herramienta de gran poder predictivo. Se aprecian patrones de respuesta diferente para las formaciones estudiadas. Mientras que para la encina se simula un área potencial continua y extensa, para el alcornoque se obtiene un área fragmentada y restringida, que se ajusta bastante a su presencia actual. La principal discrepancia del modelo presentado con esquemas de vegetación potencial anteriores radica en la ausencia de encinares y alcornocales en zonas térmicas del Levante y sur peninsular

Patterns and drivers of tree Mortality in Iberian Forests: climatic effects are modified by competition

Tree mortality is a key process underlying forest dynamics and community assembly. Understanding how tree mortality is driven by simultaneous drivers is needed to evaluate potential effects of climate change on forest composition. Using repeat-measure information fromc.400,000 trees from the Spanish Forest Inventory, we quantified the relative importance of tree size, competition, climate and edaphic conditions on tree mortality of 11 species, and explored the combined effect of climate and competition. Tree mortality was affected by all of these multiple drivers, especially tree size and asymmetric competition, and strong interactions between climate and competition were found. All species showed L-shaped mortality patterns (i.e. showed decreasing mortality with tree size), but pines were more sensitive to asymmetric competition than broadleaved species. Among climatic variables, the negative effect of temperature on tree mortality was much larger than the effect of precipitation. Moreover, the effect of climate (mean annual temperature and annual precipitation) on tree mortality was aggravated at high competition levels for all species, but especially for broadleaved species. The significant interaction between climate and competition on tree mortality indicated that global change in Mediterranean regions, causing hotter and drier conditions and denser stands, could lead to profound effects on forest structure and composition. Therefore, to evaluate the potential effects of climatic change on tree mortality, forest structure must be considered, since two systems of similar composition but different structure could radically differ in their response to climatic conditions

Evaluation of the potential index model to predict habitat suitability of forest species: the potential distribution of mountain pine (Pinus uncinata) in the Iberian peninsula

Characterization of the suitability or potentiality of a territory for forest tree species is an important source of information for forest planning and managing. In this study, we compared a relatively simple methodology to generate potential habitat distribution areas that has been traditionally used in Spain (the potential index model) with a statistical modelling approach (generalized linear model). We modelled the potential distribution of mountain pine (Pinus uncinata) in the Iberian peninsula as a working example. The potential index model generated a map of habitat suitability according to the values of an index of potentiality, whose distribution has usually divided into four categories based on quartiles (from optimum to low suitability). Considering all values of the index of potentiality as presences of mountain pine resulted in a low to moderate degree of agreement between the potential index model and the generalized linear model according to the kappa coefficient. Using the cut-off value of the index of potentiality that maximized the degree of agreement between both modelling approaches resulted in a substantial similarity between the maps of the predicted distribution of mountain pine. This cut-off value did lie in the upper-third quartile of the potential index distribution (high suitability category), and roughly coincided with the upper 30th percentile. The use of statistical techniques, which have proved to be powerful and versatile for species distribution modelling, is recommended. However, the potential index model, together with the adjustments proposed here, could be a reasonably simple methodology to predict the potential distribution of forest tree species that forest managers should take into account when evaluating forestation and afforestation projects

Relationship between self-reported dietary intake and physical activity levels among adolescents: The HELENA study

Background Evidence suggests possible synergetic effects of multiple lifestyle behaviors on health risks like obesity and other health outcomes. Therefore it is important to investigate associations between dietary and physical activity behavior, the two most important lifestyle behaviors influencing our energy balance and body composition. The objective of the present study is to describe the relationship between energy, nutrient and food intake and the physical activity level among a large group of European adolescents. Methods The study comprised a total of 2176 adolescents (46.2% male) from ten European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Dietary intake and physical activity were assessed using validated 24-h dietary recalls and self-reported questionnaires respectively. Analyses of covariance (ANCOVA) were used to compare the energy and nutrient intake and the food consumption between groups of adolescents with different physical activity levels (1st to 3rd tertile). Results In both sexes no differences were found in energy intake between the levels of physical activity. The most active males showed a higher intake of polysaccharides, protein, water and vitamin C and a lower intake of saccharides compared to less active males. Females with the highest physical activity level consumed more polysaccharides compared to their least active peers. Male and female adolescents with the highest physical activity levels, consumed more fruit and milk products and less cheese compared to the least active adolescents. The most active males showed higher intakes of vegetables and meat, fish, eggs, meat substitutes and vegetarian products compared to the least active ones. The least active males reported the highest consumption of grain products and potatoes. Within the female group, significantly lower intakes of bread and cereal products and spreads were found for those reporting to spend most time in moderate to vigorous physical activity. The consumption of foods from the remaining food groups, did not differ between the physical activity levels in both sexes. Conclusion It can be concluded that dietary habits diverge between adolescents with different self-reported physical activity levels. For some food groups a difference in intake could be found, which were reflected in differences in some nutrient intakes. It can also be concluded that physically active adolescents are not always inclined to eat healthier diets than their less active peers.The HELENA study took place with the financial support of the European Community Sixth RTD Framework Programme (Contract FOOD-CT: 2005-007034). This work was also partially supported by the European Union, in the framework of the Public Health Programme (ALPHA project, Ref: 2006120), the Swedish Council for Working Life and Social Research (FAS), the Spanish Ministry of Education (EX-2007-1124, and EX-2008-0641), and the Spanish Ministry of Health, Maternal, Child Health and Development Network (number RD08/0072) (JPRL, LAM)

Factores determinantes del secuestro de carbono en los bosques españoles: desarrollo de herramientas de análisis y prospectiva

4 páginas, 18 referencias. Comunicación presentada dentro de la temática: Mitigación transversal. Este primer workshop se celebró del 8-9, marzo, 2012, en Bilbao (España).Los bosques juegan un papel fundamental en el ciclo de carbono y por tanto en la mitigación de los efectos de los GEI (Gases de Efecto Invernadero). La vegetación arbórea supone el 70% del carbono acumulado en la vegetación mundial (Bravo et al., 2007) y alrededor del 45% del carbono terrestre (Bonan, 2008). Actualmente diversas políticas promueven el seguimiento de las tasas de almacenamiento de carbono en los bosques, como el protocolo de Kioto, la PAC o RED++ (p. ej., IGBP, 1998) así como una orientación de la gestión de los bosques hacia la mitigación del cambio climático (Canadell y Raupach, 2008). No obstante, se prevé que las emisiones de GEI seguirán aumentando a nivel mundial con lo que las políticas de adaptación son cada vez más relevantes (IPPC, 2007). Un adecuado seguimiento del efecto sumidero de los bosques requiere de un conocimiento de los factores y procesos que influyen sobre el mismo, información a diferentes escalas y niveles de organización e integración de dicha información en modelos que permitan extrapolar a otras escalas espaciales y temporales bajo diferentes escenarios (p.ej., Venter et al., 2009). En esta presentación utilizamos información del Inventario Forestal Nacional español (IFN) y del CORINE Land Cover (CLC) para modelizar algunos componentes del efecto sumidero de las formaciones forestales en España. En concreto nuestros objetivos son: (i) modelizar la variación del "stock" en diferentes regiones a partir de los cambios en la ocupación del suelo; (ii) identificar factores clave en el almacenamiento de carbono en diferentes formaciones forestales; y (iii) generar una herramienta que permita a partir de dicha información proyectar el efecto sumidero de los bosques en diferentes escenarios climáticos y de tipos de uso del suelo.Peer reviewe

Aplicación de modelos ecológicos para el análisis de la estructura y dinámica de los bosques Ibéricos en respuesta al cambio climático

31 páginas.-- 12 figuras.-- 1 tabla.-- 2 fichas.-- 102 referenciasLos modelos son simplificaciones de la realidad, su uso en Ecología permite estudiar patrones y procesos en sistemas naturales complejos de manera objetiva y relativamente sencilla. Los ecosistemas forestales son especialmente complejos de estudiar al estar formados por especies longevas y de gran tamaño, donde la experimentación es difícil. La combinación de modelos y datos observacionales a escalas espaciales regionales y continentales es particularmente útil para analizar patrones y procesos en bosques. La distribución y abundancia de organismos a lo largo del espacio y el tiempo está determinada por factores ambientales, bióticos y antrópicos, como por ejemplo las condiciones climáticas, la competencia inter- e intra-específica, la adaptación local, la plasticidad fenotípica o la gestión forestal. Por lo tanto, para el estudio de la respuesta de los bosques frente al cambio global es aconsejable el uso de modelos que incluyan estos factores de cambio y su efecto en los patrones y procesos observados. De hecho, el uso de modelos apropiadas a escalas regionales supone un paso fundamental para estimar los posibles impactos, la vulnerabilidad de los bosques y establecer prioridades en las estrategias de mitigación y adaptación al cambio climático. En el presente capítulo presentamos brevemente las técnicas más utilizadas para la parametrización de modelos en Ecología, y la aplicación de ciertos modelos para analizar los impactos y la vulnerabilidad de los bosques frente al cambio global. Dentro de las aplicaciones, incluimos desde modelos estadísticos correlacionales para analizar patrones (e.g. Modelos de Distribución de Especies o modelos de procesos demográficos) hasta modelos dinámicos que incorporan procesos demográficos para explicar patrones de distribución. Finalmente, discutimos el uso de estos modelos como herramientas para el diagnóstico de los impactos del cambio climático sobre los bosques Ibéricos y su importancia para el diseño de estrategias de adaptación.Agradecemos al Ministerio de Agricultura, Alimentación y Medio Ambiente (MAGRAMA) el acceso a información del segundo y tercer Inventario Forestal. Esta revisión ha sido fnanciada por el proyecto FUNDIV Europe (ENV.2010.2.1.4-1) y REMEDINAL-2 (S2009/AMB-1783). Agradecemos a Jaime Madrigal-González y Asier Herrero Méndez comentarios sobre versiones previas del capítulo. PRB ha estado fnanciada por una beca F.P.U. (AP2008-01325) y MBG por una beca postdoctoral Juan de la Cierva. Parte del presente capítulo de libro se basa en contenidos de la Tesis de Paloma Ruiz Benito (2013) titulada “Paterns and drivers of Mediterranean forest structure and dynamics: theoretical and management implications” (Universidad de Alcalá, 2013).Peer Reviewe

Testing scenarios for assisted migration of forest trees in Europe

International audienceOne approach to compensating for rapid climate change and protecting biodiversity is assisted migration (AM) of key tree species. However, tools for evaluating the sensitivity of target sites and identifying potential sources have not yet been developed. We used the National Forest Inventories of Spain and France to design scenarios for AM between and within both countries. We characterized sensitivity to climate change as the expected changes in volume and mortality of Pinus halepensis Miller and Pinus pinaster Aiton between the present and 2050. Target zones were selected from provenances with high sensitivity and seed zones from provenances with low sensitivity to climate change; the latter can be considered “seed refugia” as the climate changes. Three plausible scenarios for translocation to the target zone were developed on the basis of volume simulations calibrated with different planting strategies: (1) seeds only from foreign provenances; (2) foreign provenances plus local seeds; and (3) only local seeds. The results for both species show that models based on foreign “top-three” provenances always increased the standing volume of the target zone. Models run with only local seeds predicted increased volume for P. halepensis but not for P. pinaster. Our results suggest that volume and mortality trends are not always correlated with seed sources and targets, that projected provenances mortality do not follow always a southern–northern pattern and that seed refugia, if any, may be useful for compensating for the effects of climate change only in a subset of provenances. © 2015 Springer Science+Business Media Dordrech