Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Constituição da República portuguesa anotada: artigos 108 a 296

Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à lei de Direitos Autorais, não disponibilizamos a obra na íntegra. STJ00090626 342.4(469) Anot. C227c 4.ed. v.1 (2007) 4.ed. v.2 (2010

Glycerol conversion into biofuel additives by acetalization with pentanal over heteropolyacids immobilized on zeolites

Dodecamolydbophosphoric acid (HPMo) immobilized on USY zeolite was used as a catalyst for the acetalization of glycerol with pentanal at 70 °C. Catalysts were prepared with different amounts of heteropolyacid, and the most active sample was the HPMo2@Y catalyst (1.1 wt.%). The products of glycerol acetalization with pentanal were (2-butyl-1,3-dioxolan-4-yl)methanol, a five-member ring compound, and 2-butyl-1,3-dioxan-5-ol, a six-member ring compound. Good values of selectivity for the five-member ring compound (80–85%) were obtained with all materials. The reaction conditions were optimized using HPMo2@Y as a catalyst. The optimal conditions were determined to be 70 °C reaction temperature with 0.3 g catalyst and a 1:2.5 M ratio of glycerol to pentanal. The catalytic stability of HPMo2@Y was studied. The acetalization of glycerol with pentanal was performed using the same sample. High catalytic activity for HPMo2@Y was observed

Esterification of acetic acid by isoamylic alcohol over catalytic membranes of poly(vinyl alcohol) containing sulfonic acid groups

In this study, poly(vinyl alcohol) (PVA) membranes crosslinked with sulfosuccinic acid (SSA) were used for the esterification of acetic acid by isoamylic alcohol. In order to study the effects of the crosslinking degree and, simultaneously, the amount of sulfonic groups, different membranes were prepared with SSA:PVA ratios in the range of 5–40 mol%. Aiming at to eliminate the dependence between the amount of acid sites and the crosslinking degree, were also prepared PVA membranes in which the –SO3H groups were introduced by anchoring 5-sulfosalisilic acid (SA) on the PVA chains. The conversion of isoamylic alcohol increases when the amount of sulfosuccinic acid used in the polymer crosslinking is increased from 5 to 20%. However, when crosslinking degree increases from 20 to 40%, the conversion of isoamylic alcohol increases only slightly, probably due to the increase of molecules mobility restrictions, in the PVA matrix. In the case of the PVA membranes where the –SO3H groups were introduced by esterifying 5-sulfosalisilic acid on the PVA –OH groups, it was observed that membrane activity increases with the polymer crosslinking. It was also observed an increase of the activity of these membranes with the amount of –SO3H groups in the polymeric matrix. Catalytic stability of PVA membranes, prepared with SSA and SA, was evaluated by performing consecutive batch runs with the same membrane being observed, after the third run, a trend to stabilization of catalytic activity. An experiment with a membrane reactor operating under sweep gas pervaporation conditions is described

The Influence of Phase Behavior on Reactions at Supercritical Conditions: The Hydrogenation of α-Pinene

International audienceIn this paper, results on the hydrogenation of R-pinene, a liquid reactant, in supercritical (SC) CO 2 are presented. Visual observation of phase equilibria under the conditions of the reaction experiments was also performed. Much faster reaction rates were obtained when a two-phase system was present in the reactor than when a homogeneous, one-phase situation occurred. This phenomenon is attributed to the fact that SC CO 2 can dissolve extensively in the liquid reactant, leading to the formation of an "expanded liquid", which can dissolve large quantities of hydrogen. This seems to be the first time that this type of behavior is reported in the literature

Mesoporous Carbon as effective and sustainable catalyst for fine chemistry

It is well known that activated carbon with welldeveloped porosity is a promising material that have been used for several applications, from adsorption to catalysis. Research in this field has intensified in recent years, looking for new and improved characteristics and applications. Our research group, recently renamed Materials for Adsorption and Catalysis group (MAC) in LAQV-REQUIMTE, has also devoted many research work in this subject, and has developed several collaboration works with other national and international research groups in the field. Among our research group interests there is the study of catalytic properties of carbon materials and specifically mesoporous carbon. Some of the promising results were selected and summarized here, demonstrating that mesoporous carbon is an efficient and environmentally friendly heterogeneous catalyst.Es conocido que el carbón activado por su desarrollada porosidad es un material prometedor para varias aplicaciones, desde la adsorción a la catálisis. La investigación en este campo se ha intensificado en los últimos años, en busca de nuevas y mejoradas características y aplicaciones. Nuestro grupo de investigación, recientemente rebautizado grupo de materiales para la adsorción y catálisis (MAC) en LAQV-REQUIMTE, también ha dedicado muchos trabajos de investigación en este tema, y ha desarrollado varios trabajos en colaboración con otros grupos de investigación nacional e internacional. Entre los distintos intereses de investigación de nuestro grupo se encuentra el estudio de las propiedades catalíticas de materiales de carbono y específicamente, de carbones mesoporosos. Algunos de los resultados más prometedores han sido seleccionados y se resumen aquí. Estos demuestran que el carbón mesoporoso es un catalizador heterogéneo eficiente y respetuoso con el medio ambient