Caracterização e classificação de dois solos desenvolvidos de rocha básica na Zona da Mata úmida de Pernambuco, Brasil

Superfícies geomórficas nas quais há ocorrência de solos derivados de rochas básicas sob condições de clima quente e úmido são cenários ímpares para estudos de solos tropicais. O presente trabalho objetivou caracterizar e classificar solos derivados de basalto na Zona da Mata Sul do Estado de Pernambuco. Dois pedons representativos foram selecionados no município do Cabo de Santo Agostinho. Após a descrição morfológica, foram coletadas amostras de seus horizontes para caracterização física, química, mineralógica e micromorfológica. Os solos foram classificados, de acordo com o Sistema Brasileiro de Classificação de Solos (e com o "Soil Taxonomy"), como: Latossolo Vermelho-Amarelo distroférrico argissólico ("Typic Hapludox") (P1) e Nitossolo Vermelho distroférrico típico (Rhodic Paleudult") (P2). O Latossolo difere do Nitossolo por apresentar cores mais amareladas (centradas no matiz 5YR), pela ausência de pedofeições que indiquem argiluviação, maior friabilidade e pela transformação da estrutura prismática em blocos angulares e sub angulares. Ferri-argilãs e leptorrevestimentos (leptocutãs) indicam que iluviação, vertical e lateral de argila, é um processo ativo na formação do Nitossolo estudado. Na encosta estudada as elevadas precipitações pluviais, associadas à temperaturas também elevadas durante todo o ano, conduzem à formação de solos quimicamente muito pobres e mineralogicamente uniformes.Geomorphic surfaces that present soils derived from basic rocks under warm and humid climate are unique scenarios for studying tropical soils. This paper aimed to characterize and classify two pedons derived from basalt at the Atlantic Forest Zone, Pernambuco State, Northeastern coast of Brazil. Two representative pedons (P1 and P2) were selected on a hillslope at the Cabo de Santo Agostinho municipality. Field macromorphological descriptions were carried out and soil horizon were sampled for physical, chemical, mineralogical and micromorphological characterization. The soils were classified, according to the Brazilian System of Soil Classification (and US Soil Taxonomy) as: "Latossolo Vermelho-Amarelo distroférrico argissólico" (Typic Hapludox) (P1) and "Nitossolo Vermelho distroférrico típico" (Rhodic Paleudult) (P2). Pedon 1 differs from Pedon 2 in some aspects. For instance, P1 presents more yellowish colors, absence of clay illuviation, more friable consistence and the prismatic structure undergoes transformation to angular and subangular blocks. Pedon 2 presents ferri-argilans and leptocutans which indicate that vertical and lateral illuviation of clay is an active process in their formation. These chemically poor and mineralogically uniform soils are a result of the high temperature and rainfall of the studied area

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

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

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Mudanças de volume devido à variação do teor de água em um vertissolo no semiárido de Pernambuco Volume changes due to moisture variation in a vertisoil in the semi-arid region of Pernambuco state, Brazil

A instabilidade volumétrica de solos devido à mudança no teor de água é complexa e influenciada por vários fatores, entre os quais se incluem o tipo de solo, condicionantes climáticos e estados de tensão. Os Vertissolos estão entre os solos que experimentam mudança de volume, sendo uma de suas principais características morfológicas os slickensides, resultantes da sua capacidade de se contrair e fissurar com o ressecamento e se expandir com o umedecimento. Os solos que variam de volume, quando inundados por água, demandam cuidado extra, independentemente do uso que se quer dar a eles: agropecuário, para obra de engenharia ou ambos. O objetivo deste trabalho foi avaliar, por meio de ensaios edométricos simples e duplos com diferentes valores de umidade inicial e tensões externas aplicadas, a variação do volume e da tensão de expansão do solo, devido à mudança do teor de água, em um Vertissolo coletado no município de Petrolândia-PE. A tensão de expansão foi avaliada por seis métodos distintos. Os resultados mostram que a expansão, contração ou colapso do solo dependem do teor de umidade inicial e da tensão externa aplicada. A tensão de expansão é influenciada pelo caminho de tensão aplicado. As variações de volume, com o tempo, devido ao processo de mudança de umidade do solo, podem ser de expansão, expansão e colapso e só de colapso ou contração. Conclui-se que a variação de volume, devido à variação do teor de água, está associada à condição inicial em que se encontra o solo e àquela a que será submetido.<br>The volumetric instability of soils due to changes in the water content is complex and is influenced by several factors, such as soil type, climate conditions and tension state. Vertissols are soils that undergo variations in volume. One of their most important morphological features are slickensides that reflect contraction and fissuring during the drying process, and swelling during wetting. Soils that vary in volume when flooded require special care regardless of their use for agriculture, construction or both. The objective of this study was to evaluate, through both conventional edometric tests and suction-controlled tests, with different initial moisture and externally applied tension, the changes in volume and expansion tension of the soil, due to variations in the water content of a Vertisol from Petrolândia-PE. The expansion tension was measured by six methods. Results showed that soil expansion, contraction or collapse depend on the initial moisture and external tension. The expansion tension is influenced by the tension path. The volume variations with time when the soil is drying could be due to expansion, expansion and collapse and only collapse or contraction. It was concluded that the volume changes due to the water content variation are associated to the soil initial conditions and those that the soil is expected to undergo in the future

Characterization and classification of two soils derived from basic rocks in Pernambuco State Coast, Northeast Brazil

Geomorphic surfaces that present soils derived from basic rocks under warm and humid climate are unique scenarios for studying tropical soils. This paper aimed to characterize and classify two pedons derived from basalt at the Atlantic Forest Zone, Pernambuco State, Northeastern coast of Brazil. Two representative pedons (P1 and P2) were selected on a hillslope at the Cabo de Santo Agostinho municipality. Field macromorphological descriptions were carried out and soil horizon were sampled for physical, chemical, mineralogical and micromorphological characterization. The soils were classified, according to the Brazilian System of Soil Classification (and US Soil Taxonomy) as: "Latossolo Vermelho-Amarelo distroférrico argissólico" (Typic Hapludox) (P1) and "Nitossolo Vermelho distroférrico típico" (Rhodic Paleudult) (P2). Pedon 1 differs from Pedon 2 in some aspects. For instance, P1 presents more yellowish colors, absence of clay illuviation, more friable consistence and the prismatic structure undergoes transformation to angular and subangular blocks. Pedon 2 presents ferri-argilans and leptocutans which indicate that vertical and lateral illuviation of clay is an active process in their formation. These chemically poor and mineralogically uniform soils are a result of the high temperature and rainfall of the studied area

Propriedades geotécnicas de um solo expansivo tratado com cal

RESUMO Argilas expansivas são consideradas como depósitos problemáticos para obras de infraestrutura porque podem causar danos socioeconômicos e ambientais, uma vez que são susceptíveis à mudança de volume devido à variação sazonal da umidade e temperatura. A estabilização da argila expansiva é de interesse para qualquer edificação. As técnicas de estabilização podem ser mecânicas ou químicas. A cal é um agente estabilizante. Ensaios de laboratório foram realizados com o objetivo de analisar o efeito da interação da cal com um solo expansivo de Ipojuca/PE, quando é adicionado cal nas proporções de 1% a 11% em peso seco. Foram investigadas as características físicas, químicas, mineralógicas, a expansão livre e a tensão de expansão do solo natural e na mistura solo-cal. Os resultados indicam que o solo tem alta expansividade, podendo causar danos às edificações levando à demolição, principalmente as de pequeno porte. A adição de cal ao solo causou uma agregação ou floculação das partículas originais e a redução no índice de plasticidade. O percentual de 11% de cal hidratada reduziu a expansão livre e tensão de expansão a valores nulos. Isto é atribuído à capacidade de cimentação do solo tratado com a cal que reduz a tendência de absorção de água das argilas saturadas com cálcio