Electrochemical behavior of pt- a d pd-supported activated carbons with different functionalities

Due to their relatively low price, high surface area and versatile physic-chemical properties, conductive carbon materials are considered among the most promising supports of electroactive species and/or catalysts for different electrochemical devices, like supercapacitors, fuel cells, batteries, sensors, etc. [1]. However, in these applications, carbon supports are usually subjected to oxidation and/or corrosion processes, which can be promoted by the supported electroactive species and/or catalysts [2]. In this sense, although the surface functionalities of carbons seem to play a key role on their electrochemical response and stability, their influence in the presence of electroactive catalysts is still controversial. Particularly, the effect of phosphorous groups has been never reported. In this work, the influence of different oxygen and phosphorous functionalities on the electrochemical behavior of Pt- and Pd-supported activated carbons (ACs) has been studied. Various ACs showing similar surface areas (ca. 1400-1500 m2/g) and a rich variety of surface chemistry, with oxygen and phosphorous-like surface groups, were obtained by physical (CO2) (HAG800 support) or chemical (H3PO4) (HA3500 support) activation of olive stone. The ACs were used as support of Pd, Pt and Pd/Pt catalysts (Fig 1a), with nominal loadings of 0.5-1.0 wt%, by using the incipient-wetting impregnation method. The samples were characterized by N2 and CO2 adsorption, TEM, XRD, XPS, TPD experiments and different electrochemical techniques. Although the supported metals promote carbon electroxidation and/or corrosion (see the higher oxidation currents for the metalloaded sample – Fig 1b), the presence of surface phosphorous groups (HA3500-M samples) results in lower oxidation currents than in the case of P-free samples (HAG800-M samples) (Fig. 1.b). These results are in agreement with the oxidation resistance induced by phosphorous groups in oxidizing gas phase at high temperatures [3], and may support the statement that these phosphorous groups could enhance the durability of carbon-supported metal electrocatalysts for different electrochemical applications.Universidad de Málaga. Campus de Excelencia Andalucía Tech

Comportamiento electroquímico de carbones activados con presencia de grupos superficiales de fósforo

Debido a su elevada superficie específica y una combinación única de conductividad, estabilidad y gran versatilidad química-estructural, los carbones activados (CAs) se emplean como electrodos en diversas aplicaciones electroquímicas. En estas aplicaciones, los heteroátomos presentes en su superficie, tales como oxígeno y nitrógeno, juegan un papel muy importante. La presencia de grupos superficiales estables de fósforo ha sido menos estudiada, pero parece inducir efectos positivos en las propiedades electroquímicas de los materiales carbonosos, aumentando su conductividad, capacidad y/o actividad electrocatalítica en diversas reacciones. Además, se ha propuesto que dichos grupos aumentan la resistencia a la oxidación electroquímica del material en medio acuoso, lo que supone una prometedora aproximación para aumentar la densidad de energía de los supercondensadores en este medio. No obstante, a pesar de todas estas ventajas, no existen estudios que justifiquen las causas ni los mecanismos de tales efectos. En este trabajo se presenta un estudio sobre el efecto de los grupos superficiales de fósforo en la capacidad y la estabilidad electroquímica de un carbón activado.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Diseño estratégico de vanguardia

La integración del diseño con la vanguardia se observa natural, esto es, el diseño es una disciplina abductiva y la vanguardia persigue fines prospectivos, es decir, en ambos casos se trata de objetivos de posibilidad futura. De tal suerte, este libro, emanado de una parte de las ponencias rigurosamente arbitradas del Coloquio Internacional de Diseño 2016, está dividido en tres secciones o capítulos, a saber, el capítulo uno relacionado con la teoría y metodología para proyectos de diseño de vanguardia, el segundo sobre la tecnología, la innovación y la sostenibilidad de vanguardia de dichos proyectos, y finalmente el último capítulo, vinculado con la gestión estratégica de proyectos de vanguardia.La historia se forja de hechos e interpretaciones, de pasados construidos y de presentes en procesos constantes, estudiados en forma estricta por las ciencias. Por su parte, el futuro ostenta la posibilidad de ser indefinidamente planeado con base en las variopintas aproximaciones teóricas y empíricas que dan fundamento a este tipo de ciencia; éstas son denominadas prospectivas y sus bases vanguardias. Resulta importante señalar, que estas posibilidades sólo permiten tener una idea hipotética de lo que será la realidad y el mundo de vida de los seres vivos y su contexto, no obstante, se trata de la única manera racional que tiene el ser humano de prever ese futuro posible. Las distintas ciencias y disciplinas nos permiten construir históricamente estas posibilidades partiendo de datos, hechos, significados y un sinfín de informaciones que le dan cuerpo y sentido a tales posibilidades. En este sentido, la vanguardia, como base del conocimiento prospectivo, observa la necesidad de ser escrita, leída y discutida en los términos más estrictos con el fin de volver las predicciones más precisas. El diseño por su parte, es definido de manera sucinta como la disciplina proyectual estratégica y sistémica de la posibilidad, dirigida a procesos de significación utilitaria y simbólica para la comprensión –o interpretación– y modificación –o proyectación– de niveles de realidad (referentes y sujetos) desde diversos aparatos teóricos y empíricos –perspectivas disciplinarias–

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics