23 research outputs found
Biomass equations for rockrose (Cistus laurifolius L.) shrublands in North-central Spain
Aims of the study: To construct biomass weight equations for rockrose (Cistus laurifolius L.) shrublands in North-central Spain comparing different methodologies and evaluating the applicability of the current Spanish open PNOA-LiDAR data.
Area of study: The growing extension of Mediterranean shrublands associated with a high wildfire risk in a climate change scenario is considered a relevant source of biomass for energy use and bioproducts. Quantifying the biomass load of the shrublands provides essential information for adequate management, calling for the development of equations to estimate said biomass loads in the most extensive monospecific shrublands.
Materials and methods: Biomass dry weight from 290 destructive sampling plots (ø4m) and 426 individual plants along with LiDAR data from PNOA were related to dasometric parameters to fit weight per surface and weight per plant equations.
Main results: Three new equations improve rockrose biomass estimations in North-central Spain: a) Weight per unit area (tDM.ha-1) equation (Eq. 1) based on apparent biovolume (product of crown cover in percentage by average height in meters) (Radj2 0.69, MAE 26.1%, RMSE 38.4%); b) Weight per plant (kgDM.plant-1) equation (Eq. 2) from height and crown diameter (Radj2 0.87, MAE 26.5%, RMSE 45.2%) and c) Weight per unit area equation (tDM.ha-1) (Eq. 3) based on LiDAR data contrasted with field data (Radj2 0.89, MAE 15.1%, RMSE 22.9%).
Research highlights: Eq. 1 and Eq. 3 combined with high resolution LiDAR information offer rockrose (Cistus laurifolius L.) biomass estimations without added field work costs that are an improvement on certain more general studies carried out in other areas of Spain.
Keywords: Shrub; wildfire prevention; forest energy; LiDAR; weight biomass equations
Long-term effect of combination of creatine monohydrate plus β-Hydroxy β-Methylbutyrate (HMB) on exercise-induced muscle damage and anabolic/catabolic hormones in elite male endurance athletes
Producción CientíficaCreatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB) are widely studied ergogenic aids. However, both supplements are usually studied in an isolated manner. The few studies that have investigated the effect of combining both supplements on exercise-induced muscle damage (EIMD) and hormone status have reported controversial results. Therefore, the main purpose of this study was to determine the effect and degree of potentiation of 10 weeks of CrM plus HMB supplementation on EIMD and anabolic/catabolic hormones. This study was a double-blind, placebo-controlled trial where participants (n = 28) were randomized into four different groups: placebo group (PLG; n = 7), CrM group (CrMG; 0.04 g/kg/day of CrM; n = 7), HMB group (HMBG; 3 g/day of HMB; n = 7), and CrM-HMB group (CrM-HMBG; 0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before (baseline, T1) and after 10 weeks of supplementation (T2), blood samples were collected from all rowers. There were no significant differences in the EIMD markers (aspartate aminotransferase, lactate dehydrogenase, and creatine kinase) among groups. However, we observed significant differences in CrM-HMBG with respect to PLG, CrMG, and HMBG on testosterone (p = 0.006; η2p = 0.454) and the testosterone/cortisol ratio (T/C; p = 0.032; η2p = 0.349). Moreover, we found a synergistic effect of combined supplementation on testosterone (CrM-HMBG = −63.85% vs. CrMG + HMBG = −37.89%) and T/C (CrM-HMBG = 680% vs. CrMG + HMBG = 57.68%) and an antagonistic effect on cortisol (CrM-HMBG = 131.55% vs. CrMG + HMBG = 389.99%). In summary, the combination of CrM plus HMB showed an increase in testosterone and T/C compared with the other groups after 10 weeks of supplementation. Moreover, this combination presented a synergistic effect on testosterone and T/C and an antagonistic effect on cortisol compared with the sum of individual or isolated supplementation
Effect of ten weeks of creatine monohydrate plus HMB supplementation on athletic performance tests in elite male endurance athletes
Producción CientíficaCreatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB) are common ergogenic aids in the field of sports and are frequently used in an isolated way. However, there are a few studies that have investigated the effect of combining both supplements on different variables related to performance, with controversial results. Therefore, the main purpose of this study was to determine the efficacy and the degree of potentiation of 10 weeks of CrM plus HMB supplementation on sports performance, which was measured by an incremental test to exhaustion in elite male traditional rowers. In this placebo-controlled, double-blind trial, 10-week study, participants (n = 28) were randomized to a placebo group (PLG; n = 7), CrM group (0.04 g/kg/day of CrM; n = 7), HMB group (3 g/day of HMB; n = 7) and CrM-HMB group (0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before and after 10 weeks of different treatments, an incremental test was performed on a rowing ergometer to calculate the power that each rower obtained at the anaerobic threshold (WAT), and at 4 mmol (W4) and 8 mmol (W8) of blood lactate concentration. There were no significant differences in WAT and W4 among groups or in body composition. However, it was observed that the aerobic power achieved at W8 was significantly higher in the CrM-HMB group than in the PLG, CrM and HMB groups (p < 0.001; η2p = 0.766). Likewise, a synergistic effect of combined supplementation was found for the sum of the two supplements separately at WAT (CrM-HMBG = 403.19% vs. CrMG+HMBG = 337.52%), W4 (CrM-HMBG = 2736.17% vs. CrMG+HMBG = 1705.32%) and W8 (CrM-HMBG = 1293.4% vs. CrMG+HMBG = 877.56%). In summary, CrM plus HMB supplementation over 10 weeks showed a synergistic effect on aerobic power (measured as WAT, W4, and W8) during an incremental test but had no influence muscle mass
Effect of the Combination of Creatine Monohydrate Plus HMB Supplementation on Sports Performance, Body Composition, Markers of Muscle Damage and Hormone Status: A Systematic Review
Although there are many studies showing the isolated effect of creatine monohydrate (CrM) and beta-hydroxy beta-methylbutyrate (HMB), it is not clear what effect they have when they are combined. The main purpose of this systematic review was to determine the efficacy of mixing CrM plus HMB in comparison with their isolated effects on sports performance, body composition, exercise induced markers of muscle damage, and anabolic-catabolic hormones. This systematic review was carried out in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement guidelines and the PICOS model, for the definition of the inclusion criteria. Studies were found by searching PubMed/MEDLINE, Web of Science (WOS), and Scopus electronic databases from inception to July 3rd 2019. Methodological quality and risk of bias were assessed by two authors independently, and disagreements were resolved by third-party evaluation, in accordance with the Cochrane Collaboration Guidelines samples. The literature was examined regarding the effects of the combination of CrM plus HMB on sport performance using several outcome variables (athletic performance, body composition, markers of muscle damage, and hormone status). This systematic review included six articles that investigated the effects of CrM plus HMB on sport performance (two on strength performance, showing improvements in one of them; three on anaerobic performance, presenting enhancements in two of them; and one on aerobic performance, not presenting improvements), body composition (three on body mass, showing improvements in one of them; two on fat free mass, presenting increases in one of them; and two on fat mass, showing decreases in one of them) and markers of muscle damage and hormone status (four on markers of muscle damage and one on anabolic-catabolic hormones, not showing benefits in any of them). In summary, the combination of 3-10 g/day of CrM plus 3 g/day of HMB for 1-6 weeks could produce potential positive effects on sport performance (strength and anaerobic performance) and for 4 weeks on body composition (increasing fat free mass and decreasing fat mass). However, this combination seems to not show positive effects relating to markers of exercise-induced muscle damage and anabolic-catabolic hormones
The impacts of agricultural and urban land-use changes on plant and bird biodiversity in Costa Rica (1986-2014)
Costa Rica is recognized worldwide for its nature conservation policy following the traditional land-sparing approach. However, concerns have been raised about the opposite trends of the agricultural land cover changes driven by the option to expand old and new export crops after the country's external debt crisis of the 1980s. We study what happened during the last 20 years by applying landscape ecology metrics to the REDD+ land cover maps of 1986, 2001, and 2014, and statistically testing these indicators with the locations of species richness of plants and birds recorded by INBio. Our results confirm that deforestation has been reversed and most of the biodiversity considered is housed in forestland, but also that the expansion of export monocultures and urban sprawl have fragmented and isolated these tropical forests. Ecological connectivity values decreased 13% across the territory, all crops are negatively correlated with bird and plant locations, and the metropolitan expansion caused a detrimental impact on coffee agroforestry. All these outcomes are consistent with the growing deficit of the Costa Rican physical trade balance due to a faster increase of tropical exports than the growing imports of staple food, with a loss of soil organic matter filled by high doses of agrochemicals imported. Overcoming these environmental problems require a new land-sharing approach to nature conservation aimed at improving ecological connectivity through an agroecology approach combined with land-use planning to preserve the remaining green belt of the shade coffee plantations as a buffer green infrastructure in the metropolitan area
LiDAR remote sensing applied to forest resources assessment
Disponer de información precisa y actualizada de inventario forestal es una pieza clave para mejorar la gestión forestal sostenible y para proponer y evaluar políticas de conservación de bosques que permitan la reducción de emisiones de carbono debidas a la deforestación y degradación forestal (REDD). En este sentido, la tecnología LiDAR ha demostrado ser una herramienta perfecta para caracterizar y estimar de forma continua y en áreas extensas la estructura del bosque y las principales variables de inventario forestal. Variables como la biomasa, el número de pies, el volumen de madera, la altura dominante, el diámetro o la altura media son estimadas con una calidad comparable a los inventarios tradicionales de campo. La presente tesis se centra en analizar la aplicación de los denominados métodos de masa de inventario forestal con datos LIDAR bajo diferentes condiciones y características de masa forestal (bosque templados puros y mixtos) y utilizando diferentes bases de datos LiDAR (información proveniente de vuelo nacionales e información capturada de forma específica). Como consecuencia de lo anterior, se profundiza en la generación de inventarios forestales continuos con LiDAR en grandes áreas. Los métodos de masa se basan en la búsqueda de relaciones estadísticas entre variables predictoras derivadas de la nube de puntos LiDAR y las variables de inventario forestal medidas en campo con el objeto de generar una cartografía continua de inventario forestal. El rápido desarrollo de esta tecnología en los últimos años ha llevado a muchos países a implantar programas nacionales de captura de información LiDAR aerotransportada. Estos vuelos nacionales no están pensados ni diseñados para fines forestales por lo que es necesaria la evaluación de la validez de esta información LiDAR para la descripción de la estructura del bosque y la medición de variables forestales. Esta información podría suponer una drástica reducción de costes en la generación de información continua de alta resolución de inventario forestal. En el capítulo 2 se evalúa la estimación de variables forestales a partir de la información LiDAR capturada en el marco del Plan Nacional de Ortofotografía Aérea (PNOA-LiDAR) en España. Para ello se compara un vuelo específico diseñado para inventario forestal con la información de la misma zona capturada dentro del PNOA-LiDAR. El caso de estudio muestra cómo el ángulo de escaneo, la pendiente y orientación del terreno afectan de forma estadísticamente significativa, aunque con pequeñas diferencias, a la estimación de biomasa y variables de estructura forestal derivadas del LiDAR. La cobertura de copas resultó más afectada por estos factores que los percentiles de alturas. Considerando toda la zona de estudio, la estimación de la biomasa con ambas bases de datos no presentó diferencias estadísticamente significativas. Las simulaciones realizadas muestran que las diferencias medias en la estimación de biomasa entre un vuelo específico y el vuelo nacional podrán superar el 4% en áreas abruptas, con ángulos de escaneo altos y cuando la pendiente de la ladera no esté orientada hacia la línea de escaneo. En el capítulo 3 se desarrolla un estudio en masas mixtas y puras de pino silvestre y haya, con un enfoque multi-fuente empleando toda la información disponible (vuelos LiDAR nacionales de baja densidad de puntos, imágenes satelitales Landsat y parcelas permanentes del inventario forestal nacional español). Se concluye que este enfoque multi-fuente es adecuado para realizar inventarios forestales continuos de alta resolución en grandes superficies. Los errores obtenidos en la fase de ajuste y de validación de los modelos de área basimétrica y volumen son similares a los registrados por otros autores (usando un vuelo específico y parcelas de campo específicas). Se observan errores mayores en la variable número de pies que los encontrados en la literatura, que pueden ser explicados por la influencia de la metodología de parcelas de radio variable en esta variable. En los capítulos 4 y 5 se evalúan los métodos de masa para estimar biomasa y densidad de carbono en bosques tropicales. Para ello se trabaja con datos del Parque Nacional Volcán Poás (Costa Rica) en dos situaciones diferentes: i) se dispone de una cobertura completa LiDAR del área de estudio (capitulo 4) y ii) la cobertura LiDAR completa no es técnica o económicamente posible y se combina una cobertura incompleta de LiDAR con imágenes Landsat e información auxiliar para la estimación de biomasa y carbono (capitulo 5). En el capítulo 4 se valida un modelo LiDAR general de estimación de biomasa aérea en bosques tropicales y se compara con los resultados obtenidos con un modelo ajustado de forma específica para el área de estudio. Ambos modelos están basados en la variable altura media de copas (TCH por sus siglas en inglés) derivada del modelo digital LiDAR de altura de la vegetación. Los resultados en el área de estudio muestran que el modelo general es una alternativa fiable al ajuste de modelos específicos y que la biomasa aérea puede ser estimada en una nueva zona midiendo en campo únicamente la variable área basimétrica (BA). Para mejorar la aplicación de esta metodología es necesario definir en futuros trabajos procedimientos adecuados de medición de la variable área basimétrica en campo (localización, tamaño y forma de las parcelas de campo). La relación entre la altura media de copas del LiDAR y el área basimétrica (Coeficiente de Stock) obtenida en el área de estudio varía localmente. Por tanto es necesario contar con más información de campo para caracterizar la variabilidad del Coeficiente de Stock entre zonas de vida y si estrategias como la estratificación pueden reducir los errores en la estimación de biomasa y carbono en bosques tropicales. En el capítulo 5 se concluye que la combinación de una muestra sistemática de información LiDAR con una cobertura completa de imagen satelital de moderada resolución (e información auxiliar) es una alternativa efectiva para la realización de inventarios continuos en bosques tropicales. Esta metodología permite estimar altura de la vegetación, biomasa y carbono en grandes zonas donde la captura de una cobertura completa de LiDAR y la realización de un gran volumen de trabajo de campo es económica o/y técnicamente inviable. Las alternativas examinadas para la predicción de biomasa a partir de imágenes Landsat muestran una ligera disminución del coeficiente de determinación y un pequeño aumento del RMSE cuando la cobertura de LiDAR es reducida de forma considerable. Los resultados indican que la altura de la vegetación, la biomasa y la densidad de carbono pueden ser estimadas en bosques tropicales de forma adecuada usando coberturas de LIDAR bajas (entre el 5% y el 20% del área de estudio). ABSTRACT The availability of accurate and updated forest data is essential for improving sustainable forest management, promoting forest conservation policies and reducing carbon emissions from deforestation and forest degradation (REDD). In this sense, LiDAR technology proves to be a clear-cut tool for characterizing forest structure in large areas and assessing main forest-stand variables. Forest variables such as biomass, stem volume, basal area, mean diameter, mean height, dominant height, and stem number can be thus predicted with better or comparable quality than with costly traditional field inventories. In this thesis, it is analysed the potential of LiDAR technology for the estimation of plot-level forest variables under a range of conditions (conifer & broadleaf temperate forests and tropical forests) and different LiDAR capture characteristics (nationwide LiDAR information vs. specific forest LiDAR data). This study evaluates the application of LiDAR-based plot-level methods in large areas. These methods are based on statistical relationships between predictor variables (derived from airborne data) and field-measured variables to generate wall to wall forest inventories. The fast development of this technology in recent years has led to an increasing availability of national LiDAR datasets, usually developed for multiple purposes throughout an expanding number of countries and regions. The evaluation of the validity of nationwide LiDAR databases (not designed specifically for forest purposes) is needed and presents a great opportunity for substantially reducing the costs of forest inventories. In chapter 2, the suitability of Spanish nationwide LiDAR flight (PNOA) to estimate forest variables is analyzed and compared to a specifically forest designed LiDAR flight. This study case shows that scan angle, terrain slope and aspect significantly affect the assessment of most of the LiDAR-derived forest variables and biomass estimation. Especially, the estimation of canopy cover is more affected than height percentiles. Considering the entire study area, biomass estimations from both databases do not show significant differences. Simulations show that differences in biomass could be larger (more than 4%) only in particular situations, such as steep areas when the slopes are non-oriented towards the scan lines and the scan angles are larger than 15º. In chapter 3, a multi-source approach is developed, integrating available databases such as nationwide LiDAR flights, Landsat imagery and permanent field plots from SNFI, with good resultos in the generation of wall to wall forest inventories. Volume and basal area errors are similar to those obtained by other authors (using specific LiDAR flights and field plots) for the same species. Errors in the estimation of stem number are larger than literature values as a consequence of the great influence that variable-radius plots, as used in SNFI, have on this variable. In chapters 4 and 5 wall to wall plot-level methodologies to estimate aboveground biomass and carbon density in tropical forest are evaluated. The study area is located in the Poas Volcano National Park (Costa Rica) and two different situations are analyzed: i) available complete LiDAR coverage (chapter 4) and ii) a complete LiDAR coverage is not available and wall to wall estimation is carried out combining LiDAR, Landsat and ancillary data (chapter 5). In chapter 4, a general aboveground biomass plot-level LiDAR model for tropical forest (Asner & Mascaro, 2014) is validated and a specific model for the study area is fitted. Both LiDAR plot-level models are based on the top-of-canopy height (TCH) variable that is derived from the LiDAR digital canopy model. Results show that the pantropical plot-level LiDAR methodology is a reliable alternative to the development of specific models for tropical forests and thus, aboveground biomass in a new study area could be estimated by only measuring basal area (BA). Applying this methodology, the definition of precise BA field measurement procedures (e.g. location, size and shape of the field plots) is decisive to achieve reliable results in future studies. The relation between BA and TCH (Stocking Coefficient) obtained in our study area in Costa Rica varied locally. Therefore, more field work is needed for assessing Stocking Coefficient variations between different life zones and the influence of the stratification of the study areas in tropical forests on the reduction of uncertainty. In chapter 5, the combination of systematic LiDAR information sampling and full coverage Landsat imagery (and ancillary data) prove to be an effective alternative for forest inventories in tropical areas. This methodology allows estimating wall to wall vegetation height, biomass and carbon density in large areas where full LiDAR coverage and traditional field work are technically and/or economically unfeasible. Carbon density prediction using Landsat imaginery shows a slight decrease in the determination coefficient and an increase in RMSE when harshly decreasing LiDAR coverage area. Results indicate that feasible estimates of vegetation height, biomass and carbon density can be accomplished using low LiDAR coverage areas (between 5% and 20% of the total area) in tropical locations
La tecnología LIDAR en la planificación y gestión forestal: nuevas formas de cálculo de existencias y genereación de cartografía de masas forestales
Detección de cortas en choperas con imágenes Landsat
El conocimiento de las dinámicas de las masas forestales representa un reto para desarrollar una gestión forestal exitosa. Numerosos estudios han puesto en valor el uso de imágenes Landsat para la detección de aprovechamientos forestales, sin embargo, hasta el momento la mayoría de ellos se ha dedicado al estudio de las masas de coníferas. El objetivo del estudio fue generar un mapa de cortas a hecho entre 2000 y 2017 en las masas de choperas en la Comunidad Autónoma de La Rioja. Se descargaron un total de 1444 imágenes Landsat entre 1984 y 2017 que fueron analizadas con el algoritmo BFAST (Breaks for Additive Season and Trend). Se realizó un seguimiento anual de los cambios obteniéndose un mapa final de 30-m de resolución con la localización y datación de las cortas detectadas. La superficie total de cortas a hecho clasificadas (2283 ha) fueron similares a las cifras reportadas por Garnica Plywood, líder de la industria en la Rioja. Estos resultados demuestran la idoneidad de BFAST y las imágenes Landsat para la detección de cortas en ecosistemas mediterráneos, detectando satisfactoriamente varios turnos de corta. Este enfoque permite una mejor compresión del estado de nuestras masas productivas permitiendo controlar la disponibilidad de los recursos forestales. ----------ABSTRACT---------- The understanding of the forest dynamics represents a challenge for developing successful forest management. The usefulness of Landsat data has been well-demonstrated, however, so far most of the studies have devoted to the study of coniferous stands. The objective study was to map clear-cuts between 2000-2017within poplars stands in the La Rioja region. A total of 1444Landsat images were downloaded and analyzed with the BFAST algorithm. A sequential monitoring approach was followed obtaining a 30-m final map showing the location and timing of the clear-cuts detected. The total surface of clear-cuts areas (2283ha) were similar to the figures reported by the Industry leader in La Rioja, Garnica Plywood company. These findings demonstrate the suitability of BFAST and Landsat images for clear-cut detection in Mediterranean ecosystem, detecting successfully two cutting cycles. This approach allows a better understanding of the state of our forest dynamics allowing to control the availability of forest resources
Non-destructive measurement techniques for taper equation development: a study case in the Spanish Northern Iberian Range
In recent years, the technology for measuring the diameter and height of standing trees has improved significantly. These enhancements allow estimation of the volume of standing trees using stem taper equations, which traditionally have been constructed with data from felled trees, in an accurate and economically feasible way. A nondestructive method was evaluated with data from 38 pines and was validated with data from another 38 pines, both in the Northern Iberian Range (Spain). The electronic dendrometer Criterion RD1000 (Laser Technology Inc.) and the laser hypsometer TruPulse (Laser Technology Inc.) were used due to their accuracy and interoperability. The methodology was valid (unbiased and precise) measuring from a distance similar to the height of the tree. In this distance, statistical criteria and plots based on the residuals showed no clear advantage in volume estimation with models fitted with data from destructive methods against models fitted with data from the proposed non-destructive technique. This methodology can be considered useful for individual volume estimation and for developing taper equations
Coincidencias conceptuales entre el pensamiento débil y fin del arte en Vattimo y arte poshistórico en Danto : el "acontecimiento" Warhol
This work develops the coincidences between the weak thinking in Vattimo and the posthistoric art in Danto, exemplified in the work of Warhol. Contemporary art and its philosophy emerge as a contestation movement against the canonical meta-narrative in art and show points of encounter with the postmodern philosophy that also criticized the metarrelates of history for its erection as totalizing ideologies. This research shows the closeness of Vattimo to Lyotard's analysis, and also to the Heideggerian concept of Dasein as to manifest and hide the truth; closeness to the Gadamerian concept of meaning as the possibility of achieving a collective experience of art without conceptualization. Vattimo indicates the possibility of access to the truth of the work of art through the ontology of non-being and shows the opportunity to be able to understand non-canonical art but historically. Danto characterizes contemporary art as post-historical art and considers the "Warhol event" as evidence, since what is after the history of the end of art can be "anything" capable of becoming a work of art and whose freedom of expression is unprecedented. Thus, Danto defines contemporary art as the propitious time for the philosophy of art.TesisEste trabajo desarrolla las coincidencias entre el pensamiento débil en Vattimo y el arte poshistórico en Danto, ejemplificado en la obra de Warhol. El arte contemporáneo y su filosofía surgen como movimiento contestatario ante el metarrelato canónico en el arte y muestran puntos de encuentro con la filosofía postmoderna que también criticaba los metarrelatos de la historia por su erección como ideologías totalizantes. Esta investigación muestra la cercanía de Vattimo al análisis que hace Lyotard, y también al concepto heideggeriano del Dasein como manifestarse y ocultarse la verdad; cercanía al concepto gadameriano de sentido como posibilidad de lograr una experiencia colectiva del arte sin conceptualización. Vattimo indica la posibilidad del acceso a la verdad de la obra de arte mediante la ontología del no-ser y muestra la oportunidad de poder comprender el arte no canónica sino históricamente. Danto caracteriza el arte contemporáneo como arte poshistórico y considera al “acontecimiento Warhol” como evidencia, ya que lo que está después de la historia del fin del arte puede ser “cualquier cosa” capaz de convertirse en una obra de arte y cuya libertad de expresión no tiene precedentes. Así, Danto define al arte contemporáneo como la época propicia para la filosofía del arte