48 research outputs found

    CONCENTRATION AND PARTITIONING OF MACRO NUTRIENTS IN TWO MAIZE GENOTYPES AS RELATED TO SOIL WATER AVAILABILITY

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    The amount of nutrients present in crop tissue of a certain species, at certain time, is a result of the interaction between environmental conditions and genotype. This interaction is economically and ecologically important since permits the best use of fertilizers as well as different crop management which are essential for the sustainability of the productive system. In this paper, macronutrients were quantified in different parts of two adult maize plant genotypes (BRS 2121 and BR 205), which were evaluated at field conditions. The treatments imposed in this research were four water regimes (irrigation suppression at 10 days before blooming and 15, 30 and 50 days after blooming) and three types of fertilizer side dress application of N and K (10 kg N ha-1 + 90 kg K2O ha-1 at planting and 120 kg N ha-1 at V8 stage; 10 kg N ha-1 + 45 kg K2O ha-1 at planting and 45 kg K2O ha-1 + 120 kg N ha-1 at V8 stage; 10 kg N ha-1 + 30 kg K2O ha-1 at planting, 30 kg K2O ha-1 + 60 kg N ha-1 at V8 stage and 30 kg K2O ha1 + 60 kg N ha-1 at V12 growth stage). This experiment was also carried out at greenhouse conditions on young plants of the same genotypes under four water regimes, daily irrigation or each three, five or seven days. The results showed that, at field conditions, the behavior of maize plants under water deficit varied according to nutrient and part of the plant analyzed, whereas at greenhouse conditions there was a tendency of nutrients concentration in crop tissue due to water deficit

    Pervasive gaps in Amazonian ecological research

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    Pervasive gaps in Amazonian ecological research

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    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

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    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

    Waist circumference is independently associated with liver steatosis and fibrosis in LMNA-related and unrelated Familial Partial Lipodystrophy women

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    Abstract Background Lipodystrophies are a heterogeneous group of diseases characterized by the selective loss of subcutaneous adipose tissue and ectopic fat deposition in different organs, including the liver. This study aimed to determine the frequencies of liver steatosis (LS) and liver fibrosis (LF) in a sample of individuals with LMNA-related and unrelated Familial Partial Lipodystrophy. Methods This cross-sectional study included 17 women with LMNA-related FPLD and 15 women with unrelated FPLD. LS and LF were assessed using transient elastography (TE) with FibroScan®. Anthropometric and biochemical variables were included in a multiple linear regression analysis to identify the variables that were independently related to liver disease. Results Regarding the presence of LF, 22 (68.2%) women were classified as having non-significant fibrosis, and 10 (31.8%) were classified as having significant or severe fibrosis. Regarding LS, only six women (20.7%) were classified as having an absence of steatosis, and 23 (79.3%) had mild to severe steatosis. After multiple linear regression, waist circumference (but not age, body mass index, or waist-to-hip ratio) was found to be independently related to LS and LF. Among the biochemical variables, only triglyceride levels were independently related to LS but not LF. Conclusions In women with FPLD, visceral fat accumulation appears to be the most important determinant of liver disease, including LF, rather than fat scarcity in the lower limbs

    Uso do teste Lercafé para a caracterização de danos em sementes de cafeeiro Characterization of injuries in coffee seeds through Lercafé test

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    O objetivo deste trabalho foi avaliar a utilização do teste Lercafé, para estimar a germinação e caracterizar diferentes tipos de danos em sementes de cafeeiro. Utilizaram-se sementes de cafeeiro arábica cultivar Catuaí IAC 44, submetidas aos seguintes tratamentos: sementes sem dano, sementes com dano por secagem a 40 e 60ºC, e sementes brocadas. As sementes foram avaliadas pelos testes de germinação e Lercafé. Em relação aos dois tipos de danos, os resultados de germinação, estimada pelo Lercafé, apresentaram alta correlação com os obtidos pelo teste de germinação. O dano por secagem à alta temperatura caracterizou-se pelo aparecimento de manchas esverdeadas espalhadas, que atingiram parcial ou totalmente o endosperma da semente. O dano por broca caracterizou-se por uma depressão circundada por um anel de coloração verde. O teste Lercafé é eficiente para estimar a germinação e caracterizar os danos por secagem à alta temperatura e os causados por broca, em sementes de cafeeiro.<br>The objective of this work was to evaluate the use of the Lercafé test for estimating the germination and characterizing different types of injuries in coffee seeds. Seeds of arabica coffee cultivar Catuaí IAC 44 were submitted to the following treatments: nondamaged seeds, heat damage (at 40 and 60ºC), and bug damage. Seeds were assessed by the tests of germination and Lercafé. The germination results estimated by Lercafé test had high correlation with the results from the germination test for the two types of injuries. The heat damage, by drying seeds at high temperatures, was characterized by scattered green stains, partially or totally covering the seed endosperm. A sunken lesion surrounded by a green ring characterized the damage by coffee berry borer. Lercafé test is efficient to estimate the germination and to characterize the injuries by heat and coffee berry borer, in coffee seeds
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