Large lianas as hyperdynamic elements of the tropical forest canopy

Lianas (woody vines) are an important component of lowland tropical forests. We report large liana and tree inventory and dynamics data from Amazonia over periods of up to 24 years, making this the longest geographically extensive study of liana ecology to date. We use these results to address basic questions about the ecology of large lianas in mature forests and their interactions with trees. In one intensively studied site we find that large lianas (≥10 cm diameter) represent ,5% of liana stems, but 80% of biomass of well-lit upper canopy lianas. Across sites, large lianas and large trees are both most successful in terms of structural importance in richer soil forests, but large liana success may be controlled more by the availability of large tree supports rather than directly by soil conditions. Long-term annual turnover rates of large lianas are 5–8%, three times those of trees. Lianas are implicated in large tree mortality: liana-infested large trees are three times more likely to die than liana-free large trees, and large lianas are involved in the death of at least 30% of tree basal area. Thus large lianas are a much more dynamic component of Amazon forests than are canopy trees, and they play a much more significant functional role than their structural contribution suggests

Los Ciclos Económicos En ALALC O ALADI, CAN, CAFTA, MCCA: 1960-2008

El objetivo de este trabajo es analizar los ciclos económicos de los países que firman los tratados comerciales ALAC o ALADI, CAFTA, MCCA y CAN, con el fin de encontrar argumentos que demuestren o contradigan una posible sincronización de los ciclos económicos en Latinoamérica. Se realiza el análisis a través de dos metodologías, la primera, estudia las correlaciones del ciclo económico, para la cual, se hace uso del filtro de Hodrick y Prescott (HP) para extraer el componente de tendencia de las series y la segunda, por medio de una medida no paramétrica denominada índice de concordancia presentado por Harding y Pagan (1999). En síntesis, se encuentran relaciones interesantes entre algunos de sus miembros, pero sus vínculos no son lo suficientemente fuertes para hablar de un ciclo común, por esta razón se puede afirmar que no se presentan indicios de sincronización económica en los tratados analizados

Hydrothermal assisted synthesis of iron oxide-based magnetic silica spheres and their performance in magnetophoretic water purification

Porous Magnetic Silica (PMS) spheres of about 400 nm diameter were synthesised by one-pot process using the classical Stӧber method combined with hydrothermal treatment. Maghemite nanoparticles (γ-Fe2O3) were used as fillers and cetyltrimethylammonium bromide (CTAB) was used as templating agent. The application of the hydrothermal process (120 °C during 48 h) before the calcination leads to the formation of homogeneous and narrow size distribution PMS spheres. X-ray diffraction patterns (XRD), Infrared measurements (FTIR) and Transmission Electron microscopy (TEM) methods were used to determine the composition and morphology of the obtained PMS spheres. The results show a homogeneous distribution of the γ-Fe2O3 nanoparticles in the silica matrix with a “hollow-like” morphology. Magnetophoresis measurements at 60 T m−1 show a total separation time of the PMS spheres suspension of about 16 min. By using this synthesis method, the limitation of the formation of silica spheres without incorporation of magnetic nanoparticles is overcome. These achievements make this procedure interesting for industrial up scaling. The obtained PMS spheres were evaluated as adsorbents for Ni2+ in aqueous solution. Their adsorption capacity was compared with the adsorption capacity of magnetic silica spheres obtained without hydrothermal treatment before calcination process. PMS spheres show an increase of the adsorption capacity of about 15% of the initial dissolution of Ni2+ without the need to functionalize the silica surface.Fundação para a Ciência e a Tecnologia (FCT

Validación de un algoritmo de procesamiento de imágenes Red Green Blue (RGB), para la estimación de proteína cruda en gramíneas vs la tecnología de espectroscopía de infrarrojo cercano (NIRS)

The present work study aimed at evaluating the accuracy of the computerized algorithm included in the TaurusWebs ® software, which allows to calculate the percent of crude protein (% CP) in the dry matter of grasses, from images of grasslands taken by a drone with Red Green Blue – RGB- cameras. The %PC measurements calculated by the algorithm were compared to a reference, Near Infrared Reflectance Spectroscopy (NIRS), from the Corpoica (Agrosavia) Laboratory calibrated for grasses. Forty-two samples were taken for NIRS, 18 of high tropic grasses in Cundinamarca: kikuyo, Pennisetum clandestinum; false poa, Holcus lanatus; Brazilian grass, Phalaris arundinacea and 24 from the low tropics in Tolima, Colombia: pangola, Digitaria decumbens; pará, Brachiaria mutica; Bermuda, Cynodon dactylon and coloswana, Bothriochloa pertusa. The results of the NIRS were compared against the evaluations made with the algorithm to the images of the grasses, coming from the pasture where the samples were taken. The results were compared using nonparametric statistics, the Kendall correlation test and Spearman, rho=0.83 and the Kruskal Wallis test. No differences were found between the result of the %PC of grasses measured by NIRS vs. the %PC measured by the RGB image analysis algorithm. In conclusion, the information generated with the algorithm can be used for analysis jobs of the %PC in grasses.            El presente trabajo estuvo orientado a evaluar la precisión del algoritmo de análisis de imágenes Red, Green, Blue (RGB), incluido en el software TaurusWebs ®, que permite calcular el porcentaje de proteína cruda de la materia seca (%PC) de las gramíneas a partir de imágenes de las praderas tomadas por un dron acoplado con cámaras RGB. Se compararon las mediciones del %PC calculadas por el algoritmo frente a un referente, Near Infrared Reflectance Spectroscopy (NIRS), del laboratorio de Corpoica (Agrosavia), calibrado para gramíneas. Se tomaron 42 muestras para NIRS, 18 de gramíneas de trópico alto en Cundinamarca: kikuyo, Pennisetum clandestinum; falsa poa, Holcus lanatus; pasto brasilero, Phalaris arundinacea y 24 de trópico bajo en Tolima, Colombia: pangola, Digitaria decumbens; pará, Brachiaria mutica; bermuda, Cynodon dactylon y colosuana, Bothriochloa pertusa. Los resultados del NIRS se compararon contra las evaluaciones hechas con el algoritmo de las imágenes de las gramíneas provenientes del mismo potrero donde se tomaron las muestras. Los resultados fueron comparados usando las pruebas no paramétricas de correlación de Kendall, rho=0.83 y de Kruskal Wallis. No se encontraron diferencias entre el resultado del %PC de las gramíneas medida por NIRS vs el %PC medida por el algoritmo de análisis de imágenes RGB. En conclusión, la información generada con el algoritmo se puede utilizar para trabajos de análisis del %PC en gramíneas

Análisis Campo-Sustancia de TRIZ para el uso de Trichoderma asperelloides como antagónico en Citrus sinensis

La teoría de solución de problemas de inventiva (TRIZ), es el resultado del análisis minucioso de patentes a nivel mundial, forma parte de un sistema de principios y algoritmos donde se amplifica la posibilidad de encontrar soluciones innovadoras a problemas científicos, superando la inercia psicológica basada en paradigmas. El presente trabajo propone un análisis biológico utilizando la herramienta analítica TRIZ con el uso del Análisis Campo-Sustancia (Su-Field) originalmente destinado a resolver problemas de ingeniería para determinar el efecto antagónico de Trichoderma asperelloides frente a Fusarium, patógeno presentado en plantas de cítricos encontrando como el resultado final ideal el uso de T. asperelloides como agente de control patógeno en plantas de cítricos (Citrus sinensis) en el norte de Veracruz, México

Increasing biomass in Amazonian forest plots

A previous study by Phillips et al. of changes in the biomass of permanent sample plots in Amazonian forests was used to infer the presence of a regional carbon sink. However, these results generated a vigorous debate about sampling and methodological issues. Therefore we present a new analysis of biomass change in old-growth Amazonian forest plots using updated inventory data. We find that across 59 sites, the above-ground dry biomass in trees that are more than 10 cm in diameter (AGB) has increased since plot establishment by 1.22 ± 0.43 Mg per hectare per year (ha-1 yr-1), where 1 ha = 104 m2), or 0.98 ± 0.38 Mg ha-1 yr-1 if individual plot values are weighted by the number of hectare years of monitoring. This significant increase is neither confounded by spatial or temporal variation in wood specific gravity, nor dependent on the allometric equation used to estimate AGB. The conclusion is also robust to uncertainty about diameter measurements for problematic trees: for 34 plots in western Amazon forests a significant increase in AGB is found even with a conservative assumption of zero growth for all trees where diameter measurements were made using optical methods and/or growth rates needed to be estimated following fieldwork. Overall, our results suggest a slightly greater rate of net stand-level change than was reported by Phillips et al. Considering the spatial and temporal scale of sampling and associated studies showing increases in forest growth and stem turnover, the results presented here suggest that the total biomass of these plots has on average increased and that there has been a regional-scale carbon sink in old-growth Amazonian forests during the previous two decades

Efficiency analysis of the visibility of Latin American universities and their impact on the ranking web

The study analyzes the factors that contribute to the technical efficiency of the visibility of the universities included in the Top100 of the Latin American Universities Ranking Web published by Webometrics database in January, 2017. Data Envelopment Analysis (DEA) was used to calculate the contributions of input variables to efficiency. As data sources for inputs, the study considers the academic data published on the web of each university, the content and profiles displayed from Google Scholar (GS), data by university published in ResearchGate as a scientific network, and finally, data from social networks as Twitter and Facebook accounts of the respective institutions. The postgraduate offer, visibility in GS, and the use of scientific and social networks contribute favorably to the web positioning of Latin American universities

Garantismo y crisis de la justicia

Esta obra representa una importante reflexión teórica producto de la labor investigativa de sus autores, en torno a uno de los problemas de mayor actualidad en la sociedad contemporánea, cual es, la tensión permanente que se presenta entre la necesidad que tiene el Estado de garantizar un orden o control social y al mismo tiempo, la exigencia actual de la garantía y protección de los derechos fundamentales

Pattern and process in Amazon tree turnover, 1976-2001

Previous work has shown that tree turnover, tree biomass and large liana densities have increased in mature tropical forest plots in the late twentieth century. These results point to a concerted shift in forest ecological processes that may already be having significant impacts on terrestrial carbon stocks, fluxes and biodiversity. However, the findings have proved controversial, partly because a rather limited number of permanent plots have been monitored for rather short periods. The aim of this paper is to characterize regional-scale patterns of 'tree turnover' (the rate with which trees die and recruit into a population) by using improved datasets now available for Amazonia that span the past 25 years. Specifically, we assess whether concerted changes in turnover are occurring, and if so whether they are general throughout the Amazon or restricted to one region or environmental zone. In addition, we ask whether they are driven by changes in recruitment, mortality or both. We find that: (i) trees 10 cm or more in diameter recruit and die twice as fast on the richer soils of southern and western Amazonia than on the poorer soils of eastern and central Amazonia; (ii) turnover rates have increased throughout Amazonia over the past two decades; (iii) mortality and recruitment rates have both increased significantly in every region and environmental zone, with the exception of mortality in eastern Amazonia; (iv) recruitment rates have consistently exceeded mortality rates; (v) absolute increases in recruitment and mortality rates are greatest in western Amazonian sites; and (vi) mortality appears to be lagging recruitment at regional scales. These spatial patterns and temporal trends are not caused by obvious artefacts in the data or the analyses. The trends cannot be directly driven by a mortality driver (such as increased drought or fragmentation-related death) because the biomass in these forests has simultaneously increased. Our findings therefore indicate that long-acting and widespread environmental changes are stimulating the growth and productivity of Amazon forests

After trees die: quantities and determinants of necromass across Amazonia

The Amazon basin, one of the most substantial biomass carbon pools on earth, is characterised by strong macroecological gradients in biomass, mortality rates, and wood density from west to east. These gradients could affect necromass stocks, but this has not yet been tested. This study aims to assess the stocks and determinants of necromass across Amazonian forests. Field-based and literature data were used to find relationships between necromass and possible determinants. Furthermore, a simple model was applied to estimate and extrapolate necromass stocks across <i>terra firma</i> Amazonian forests. In eight northwestern and three northeastern Amazonian permanent plots, volumes of coarse woody debris (≥10 cm diameter) were measured in the field and the density of each decay class was estimated. Forest structure and historical mortality data were used to determine the factors controlling necromass. Necromass is greater in forests with low <i>stem</i> mortality rates (northeast) rather than in forests with high <i>stem</i> mortality rates (northwest) (58.5±10.6 and 27.3±3.2 Mg ha<sup>−1</sup>, respectively). Using all published necromass values, we find that necromass across <i>terra firma</i> forests in Amazonia is positively related to both forest dynamics (mortality <i>mass</i> inputs and a surrogate for decomposition rate (average wood density of living trees)) and forest structure (biomass), but is better explained by forest dynamics. We propose an improved method to estimate necromass for plots where necromass has not been measured. The estimates, together with other actual measurements of necromass, were scaled-up to project a total Amazonian necromass of 9.6±1.0 Pg C. The ratio of necromass (on average weighted by forest region) to coarse aboveground biomass is 0.127. Overall, we find (1) a strong spatial trend in necromass in parallel with other macroecological gradients and (2) that necromass is a substantial component of the carbon pool in the Amazon