61 research outputs found

    Mudas de Eucaliptus urophylla sob diferentes concentrações de Cr: sintomas de toxidez e efeitos no crescimento / Eucalyptus urophylla cuttings under different concentrations of Cr: toxicity symptoms and effects on growth

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    Com o objetivo de avaliar os efeitos da toxidez de cromo (Cr) sobre o crescimento e desenvolvimento de mudas de Eucaliptus urophylla, foi instalado um experimento em casa-de-vegetação no Departamento de Ciência do Solo da Universidade Federal de Lavras. Foram utilizadas diferentes concentrações de Cr (0,00; 0,04; 0,08; 0,16; 0,32 e 0,64 mM) fornecido como [Cr(NO3)3.9H2O], em solução nutritiva de Clark. Após cinco semanas de exposição aos tratamentos, as plantas exibiram sintomas de toxidez traduzidos em redução no crescimento, queda de folhas, encurtamento e escurecimento de raízes e com a elevação das concentrações estas se tornavam mais finas e quebradiças. A elevação nas concentrações de Cr na solução nutritiva exerceu efeitos significativos sobre diversos parâmetros vegetativos estudados: altura e incremento em altura, diâmetro e incremento em diâmetro, produção de matéria seca nos quais mostraram redução significativa com o aumento da dose do metal pesado a partir da concentração de 0,08 mM Cr. De maneira geral, a aplicação de Cr acima de 0,08 mM reduz o crescimento de todos os órgãos da planta

    NUTRIÇÃO MINERAL DE PIMENTA ORNAMENTAL SOB DEFICIÊNCIAS NUTRICIONAIS

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    O objetivo desse trabalho foi avaliar o crescimento e nutrição mineral de pimenta ornamental sob deficiências nutricionais. O experimento foi realizado em casa de vegetação do Departamento de Ciência do Solo na Universidade Federal de Lavras, Lavras-MG. O delineamento estatístico utilizado foi o inteiramente casualizado com três repetições, contendo doze tratamentos, em solução nutritiva baseada na solução de Hoagland & Arnon (1950). Os tratamentos foram: solução nutritiva completa (controle) e soluções nutritivas com omissões individuais de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn. Após a germinação, as mudas foram transferidas para a solução nutritiva completa com 10% da sua força iônica (período de adaptação), as quais permaneceram sob aeração constante. Após a adaptação, as plantas foram selecionadas quanto à uniformidade de tamanho da parte aérea e raízes e transplantadas para vasos de plástico (um litro) com solução nutritiva a 100%, nos quais foram estabelecidos os tratamentos. A colheita das plantas foi realizada aos XX dias de cultivo, sendo, então, o material seco e pesado para a obtenção da massa de matéria seca. Após a secagem, procedeu-se também à moagem para posterior análise química. As plantas cultivadas sob omissões de N, P, K, Ca, Mg, S e B são as mais afetadas com relação à altura comparando-as as plantas dos demais tratamentos. As menores produções de massa de matéria seca da parte aérea são obtidas em plantas de pimenta cultivadas sob omissões de N, K e P. As omissões nutricionais que mais restringem o crescimento do sistema radicular de plantas de pimenta ornamental são K, B e N. Os teores de P, K, Ca, Mg e S encontrados na parte aérea de pimenta ornamental no tratamento completo são 2,53; 28,20; 10,67; 3,88 e 7,93 g kg-1, respectivamente. A ordem decrescente de acúmulo de macronutrientes na parte aérea da pimenta ornamental em solução nutritiva é K>Ca>S>Mg>P

    Entre consumos suntuários e comuns: a posse de objetos exóticos entre alguns habitantes do Porto (séculos XVI – XVII)

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    O estudo da documentação referente aos doadores da Misericórdia do Porto entre os séculos XVI e XVII, através dos objetos exóticos patentes nos respectivos testamentos e inven- tários – estes últimos provenientes de uma área que se estende de Macau ao Brasil –, permite discernir uma panóplia de objetos que mudaram a cultura material dos portuenses em contato com os territórios da expansão portuguesa. Um levantamento sistemático permitiu já rastrear, até o ano de 1699, 257 doadores, dos quais se apresentarão aqui apenas alguns, referentes a benfeitores que, não obstante possuírem bens móveis nesse âmbito, não são dados como tendo estado nos territórios de expansão transoceânica. Argumentar-se-á que essa circulação de objetos não foi exclusiva das elites nobiliárquicas, nem dos grandes centros urbanos, pelo que a sua difusão atingiu maiores proporções do que aquelas que a historiografia tem admitido até agora. A cidade em observação neste estudo – o Porto dos séculos XVI e XVII – estava longe de ser das maiores da Europa nesse período, quer em dimensão territorial, quer em efetivos populacionais, embora se situasse numa região de demografia pujante, que canalizou os seus excedentes desde cedo para a emigração interna e externa – o Entre Douro e Minho. Como teremos ocasião de verificar, fidalgos e nobres possuíam bens exóticos, mas estes encontravam-se também entre mercadores e até artesãos mais desafogados. Por outro lado, nem todos os objetos provenientes dos espaços da expansão transoceânica devem ser conotados com bens de luxo.The study of the sources referring to the donors of the Misericórdia of the city of Porto during the sixteenth and seventeenth centuries has revealed the presence of numerous exotic objects in their last wills and inventories. A survey has traced 257 donors until 1699, some of them having died in an area that extends from Macao to Brazil. Only a small number of cases shall be presented here, pertaining to benefactors who, in spite of owning objects of transoceanic origin, seem to have remained in mainland Portugal. It shall be argued that the circulation of objects has not been exclusive either to the elites of the nobility or to the large urban centres, their diffusion having been on a larger scale than what has been admitted until now. The city under scrutiny in this study – Porto during the sixteenth and seventeenth centuries – was not one of the bigger cities in this period, either in what respects to size or population, although it was located in an area of flourishing demography, that channelled its surplus population early on to internal and external emigration. Fidalgos and noblemen owned exotic goods, but these were to be found among merchants and even well-to-do artisans. On the other hand, not all objects originating from the areas of transoceanic expansion should be considered as luxury goods.info: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 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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    Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

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    Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

    The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

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    Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications

    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

    Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

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    From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions
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