Key structural features of Boreal forests may be detected directly using L-moments from airborne lidar data

This article introduces a novel methodology for automated classification of forest areas from airborne laser scanning (ALS) datasets based on two direct and simple rules: L-coefficient of variation Lcv=0.5 and L-skewness Lskew=0, thresholds based on descriptors of the mathematical properties of ALS height distributions. We observed that, while Lcv>0.5 may represent forests with large tree size inequality, Lskew>0 can be an indicator for areas lacking a closed dominant canopy. Lcv=0.5 discriminated forests with trees of approximately equal sizes (even tree size classes) from those with large tree size inequality (uneven tree size classes) with kappa κ = 0.48 and overall accuracy OA = 92.4%, while Lskew=0 segregated oligophotic and euphotic zones with κ = 0.56 and OA = 84.6%. We showed that a supervised classification could only marginally improve some of these accuracy results. The rule-based approach presents a simple method for detecting structural properties key to tree competition and potential for natural regeneration. The study was carried out with low-density datasets from the national program on ALS surveying of Finland, which shows potential for replication with the ALS datasets typically acquired at nation-wide scales. Since the presented method was based on deductive mathematical rules for describing distributions, it stands out from inductive supervised and unsupervised classification methods which are more commonly used in remote sensing. Therefore, it presents an opportunity for deducing physical relations which could partly eliminate the need for supporting ALS applications with field plot data for training and modelling, at least in Boreal forest ecosystems

LiDAR Scan Density and Spatial Resolution Effects on Vegetation Fuel Type Mapping

This article presents the performance of a vegetation fuel type (FT) classification based on conditional rules according to the Prometheus system, including an analysis of the effect of cell size and scan density on mapping vertical structural types, exemplified as FT, using exclusively LiDAR data. Since the Prometheus system does not specify any criterion for the minimum extension where those methodologies can be applied, we searched for the optimal classification cell size by gridding the study area at 20 and 40 m cell sizes. We also included a study of the effects of varying the scan density from 2 to 0.5 pulses·m-2. To validate the classification method, we used a stratified random sampling without replacement of 15 cells per FT and made an independent visual assessment of FTs. The best results in terms of precision were obtained for the combination of 0.5 pulses·m-2 and 20 m-resolution dataset, with an overall accuracy of 84.13%. It was also showed that an increase in scan density would not improve the global accuracy of the classification, but it would be desirable for a better detection of the shrub stratum

Reactivación de la frontera agrícola y aumento de la tasa de deforestación al norte de la BR - 163, municipios de Santarém y Belterra, Pará, Brasil (1999 - 2004).

A reativação da fronteira agrícola na Amazônia Central, região comandada por Santarém, caracterizada pela chegada de novos agentes sociais e pela transformação dos sistemas agropecuários, está gerando novas dinâmicas socioeconômicas e expressivos impactos ambientais, nomeadamente o aumento da taxa de desmatamento. Através desse trabalho, esperamos ajudar na compreensão deste processo dinâmico, a partir da determinação da área desmatada no período estudado (1999-2004), estabelecendo quais são os fatores envolvidos na abertura de novas áreas de selva tropical para a sua incorporação ao sistema produtivo na região Norte da Cuiabá-Santarém (BR-163) e os efeitos que este processo tem na reorganização do espaço geográfico.The reactivation of the agricultural frontier in Central Amazonia, a region that gravitates around the Santarém, is characterized by the arrival of new social agents and the transformation of the current farming systems. This reactivation is generating new social and economic dynamics and significant environmental impacts, specifically the increase in the rate of deforestation. Currently, we are attempting to understand this dynamic process by analyzing the area(s) which suffered from deforestation in the studied period (1999-2004). Specifically, we are trying to determine which factors are good indicators that a new area of tropical rainforest will be opened for its incorporation into the productive system in the North region of Cuiabá-Santarém (BR-163). We also hope to demonstrate the effects that this process has in the reorganization of the geographic space.La reactivación de la frontera agrícola en la Amazonia Central, región que gravita en torno al núcleo urbano de Santarém, caracterizada por la llegada de nuevos agentes sociales y la transformación de los sistemas agropecuarios, está generando nuevas dinámicas socioeconómicas y significativos impactos ambientales, substancialmente el aumento de la tasa de deforestación. A través del presente trabajo, se pretende ayudar en la comprensión de este proceso dinámico, a partir de la comprobación del área deforestada en el periodo estudiado (1999-2004), determinando cuáles son los factores implicados en la apertura de nuevas áreas de selva tropical para su incorporación al sistema productivo en la región Norte de la Cuiabá-Santarém (BR-163) y los efectos que este proceso tiene en la reorganización del espacio geográfico

Desempeño productivo del capaz (Pimelodus grosskopfii, Steindachner, 1879) bajo diferentes densidades de siembra y de contenido de proteína en la dieta

The capaz is a representative of the family Pimelodidae fish, whose production comes from fishing in Magdalena River and the Embalse de Betania. Although a species of commercial interest, studies on its cultivation are scarce. In order to evaluate productive performance of capaz under different densities and different levels of protein in the diet, were used 450 fingerlings with an average weight of 37.6 ± 2.4 g and an initial size of 17.5 ± 1.7 cm preconditioned for consumption of commercial concentrate and during a productive period of six months in floating cages. The animals were divided into 2 densities (25 and 50 fish / m3) and fed 2 different protein levels Gross (PB) in the diet (25 and 32 %). Best results were obtained for planting density of 25 fish / m3 and concentrate fed 25 % protein, with the highest values in terms of weight gain (150 ± 4 g), specific growth rate (0.8 ± 0.002) and relative growth factor (7.39 ± 0.06). According to the results obtained it can be concluded that the density of 25 fish / m3 and food with a content of 25 % protein present the best conditions for the commercial cultivation of Pimelodus grosskopfii in floating cages.El capaz es un pez representante de la familia Pimelodidae, cuya producción proviene de la pesquería en el río Magdalena y en la represa de Betania. Aunque es una especie de interés comercial, los estudios sobre su cultivo aún se desconocen. Con el objetivo de evaluar el desempeño productivo del capaz bajo diferentes densidades de siembra y con diferentes niveles de proteína en la dieta, se utilizaron 450 alevinos con un peso promedio de 37,6 ± 2,4 g y una talla inicial de 17,5 ± 1,7 cm, previamente acondicionados a consumo de concentrado comercial y durante un periodo productivo de 6 meses en jaulas flotantes en el embalse de Betania. Los animales fueron distribuidos en dos densidades de siembra (25 y 50 peces/m3) y alimentados con dos diferentes niveles de Proteína Bruta (PB) en la dieta (25 y 32 %). Se obtuvieron mejores resultados para la densidad de siembra de 25 peces/m3 y alimentados con concentrado de 25 % de proteína, con los valores más altos en cuanto a ganancia de peso (150 ± 4 g), tasa de crecimiento especifico (0,8 ± 0,002) y factor de crecimiento relativo (7,39 ± 0,06). De acuerdo con los resultados obtenidos se puede concluir que la densidad de 25 peces/m3 y el alimento con un contenido de 25 % de proteína presentan las mejores condiciones para el cultivo comercial de Pimelodus grosskopfii en jaulas flotantes

Nanomechanics of tip-link cadherins

Hearing and balance rely on the transduction of mechanical stimuli arising from sound waves or head movements into electrochemical signals. This archetypal mechanoelectrical transduction process occurs in the hair-cell stereocilia of the inner ear, which experience continuous oscillations driven by undulations in the endolymph in which they are immersed. The filamentous structures called tip links, formed by an intertwined thread composed of an heterotypic complex of cadherin 23 and protocadherin 15 ectodomain dimers, connect each stereocilium to the tip of the lower sterocilium, and must maintain their integrity against continuous stimulatory deflections. By using single molecule force spectroscopy, here we demonstrate that in contrast to the case of classical cadherins, tip-link cadherins are mechanoresilient structures even at the exceptionally low Ca2+ concentration of the endolymph. We also show that the D101G deafness point mutation in cadherin 23, which affects a Ca2+ coordination site, exhibits an altered mechanical phenotype at the physiological Ca2+ concentration. Our results show a remarkable case of functional adaptation of a protein’s nanomechanics to extremely low Ca2+ concentrations and pave the way to a full understanding of the mechanotransduction mechanism mediated by auditory cadherinsThis work was supported by the BIO2010-22275 grant from the Spanish Ministry of Science and Innovation (MICINN) to M.C.-V

Development of a passive mini-direct ethanol fuel cell : effect of mea assembly parameters by hot pressure.

This paper presents preliminary results on the design, construction and evaluation of a passive mini direct ethanol fuel cell (DEFC), capillary fed with 2 mol l-1 aqueous ethanol, at a rate of 2.03 μL min-1, and air oxygen in the cathode through an air vent. Parameters such as pressure, temperature and time of manufacturing a membrane-electrode assembly (MEA) by hot-pressure were evaluated. As the electrode holder used a 0.25 cm2 carbon tissue which was deposited on the catalytic layer (C. L.) for both the anode (0.8 mg cm-2 of PtRu/C) and the cathode (0.8 mg cm-2 of Pt/C), Nafi on® 115 membranes were used as the electrolyte. The results show, an average power density of 302 μWcm2 under the best conditions used, a catalytic layer with a Nafi on percentage of 50% at 25 °C. A temperature of 125 °C, a pressure of 49.2 Kg/cm2, and 90 seconds duration were used to obtain the MEA

Development of a Passive Mini-Direct Ethanol Fuel Cell: Effect of Mea Assembly Parameters by Hot Pressure

This paper presents preliminary results on the design, construction and evaluation of a passive mini direct ethanol fuel cell (DEFC), capillary fed with 2 mol l-1 aqueous ethanol, at a rate of 2.03 μL min-1, and air oxygen in the cathode through an air vent. Parameters such as pressure, temperature and time of manufacturing a membrane-electrode assembly (MEA) by hot-pressure were evaluated. As the electrode holder used a 0.25 cm2 carbon tissue which was deposited on the catalytic layer (C. L.) for both the anode (0.8 mg cm-2of PtRu/C) and the cathode (0.8 mg cm -2of Pt/C), Nafi on® 115 membranes were used as the electrolyte. The results show, an average power density of 302 μWcm2 under the best conditions used, a catalytic layer with a Nafi on percentage of 50% at 25 °C. A temperature of 125 °C, a pressure of 49.2 Kg/cm2, and 90 seconds duration were used to obtain the MEA

Evaluación de la primera alimentación en larvas de capaz Pimelodus grosskopfii bajo condiciones de laboratorio

RESUMEN Objetivo. Evaluar el desempeño y sobrevivencia de larvas de capaz Pimelodus grosskopfii suministrando alimento vivo (Cladóceros, Copépodos y Artemia salina). Materiales y métodos. Larvas de capaz fueron ubicadas en recipientes plásticos con un volumen útil de 3 L, a una densidad de 10 larvas L-1, fueron alimentadas cuatro veces al día, durante 15 días con nauplios de Artemia recién eclosionadas, Cladóceros de los géneros Moina y Ceriodaphnia y Copépodos calanoides. Las larvas de capaz se pesaron y se midieron al inicio y al final del experimento para estimar ganancia en peso (GP), ganancia en longitud (GL), tasa de crecimiento específico (TCE), Factor de crecimiento relativo (FCR) y sobrevivencia (S) Resultados. El tratamiento que presentó los mejores resultados en GP, GL y S fue el de larvas alimentadas con nauplios de Artemia (3.8 ± 0.2 mg, 8 ± 0.7 mm y 48.3% respectivamente) seguido de los tratamientos donde adicionó cladóceros y copépodos Conclusiones. Los nauplios de Artemia fue el tratamiento que presentó los mejores resultados en las variables productivas evaluadas en larvas de P. grosskopfii al inicio de su alimentación exógena