71 research outputs found
Boro afeta o crescimento e a ultra-estrutura da mamoneira
A mamoneira é uma oleaginosa com grande potencial para a geração de renda na agricultura familiar e para produção de matéria prima para a indústria química e setor energético brasileiro, especialmente em regiões do semi-árido nordestino. A deficiência de boro (B) ocorre de forma generalizada no Brasil e a aplicação excessiva deste micronutriente pode causar toxicidade. Este estudo avalia o desenvolvimento e os efeitos ultra-estruturais de deficiência e toxicidade de boro em mamoneira. O experimento foi realizado em condições de casa de vegetação, com vasos de 10 L de solução nutritiva. Foram utilizados três tratamentos: testemunha (sem B); 0,27 e 5,40 mg L-1 B, uma planta por vaso, em delineamento experimental inteiramente ao acaso com três repetições. A produção de matéria seca de cada parte da planta foi avaliada e o teor de boro determinado. Foram observados os efeitos morfológicos e as alterações na ultra-estrutura celular nas folhas e pecíolos, através da técnica de microscopia eletrônica de transmissão e varredura. A produção de matéria seca da mamoneira foi afetada em condições de deficiência de boro, mas não em condições de toxicidade (5,4 mg L-1 B). Neste último tratamento foram constatadas cloroses nos bordos de folhas velhas e ausência de grânulos de amido. Na omissão de boro, as plantas apresentaram deformação de folhas novas, morte do meristema apical, engrossamento da lamela média, ausência de grânulos de amido nos cloroplastos e desorganização dos vasos condutores do pecíolo. O desenvolvimento e a produção da mamoneira são afetados em condições de deficiência de boro mas não na condição de toxicidade.The cultivation of oleaginous plants like the castor bean guarantees employment for agricultural families and can contribute in energy and chemical sectors, especially in the northeastern semi-arid regions of Brazil. Boron (B) deficiency is a widespread nutritional disorder despite the fact that various anthropogenic sources with high B content may increase soil B to toxic levels for plants. The present study was designed to investigate the ultrastructural effects of boron deficiency and toxicity on castor bean plants which were grown under greenhouse condition using plastic containers with 10 L of nutrient solution. Boron treatments comprised: control (no B); 0.27 mg L-1, 5.40 mg L-1 B pots (one plant per pot), tested in a completely randomized design with three replicates. The dry matter of all plant parts and B concentration were determined. Cellular ultrastructure was evaluated by transmission and scanning electron microscopy on samples of leaves and petioles. Dry matter yield was affected by the B absence treatment but there was no difference for the 5.4 mg L-1 B (toxic conditions) treatment. A marginal leaf burn at edge and tips of oldest leaves and absence of starch granules in chloroplasts were noted for the B toxicity treatment. The deformation of the youngest leaves, the death of the apical meristem as well as the swelling of the middle lamella, absence of starch granules in chloroplasts and petiole vessels untidily were observed in the B absent treatment. It is concluded that the production and development of castor bean plants is affected by boron deficiency, but not for boron toxicity conditions
Multi-scale homogenization of caddisfly metacomminities in human-modified landscapes
The multiple scale of stream networks spatial organization reflects the hierarchical arrangement of streams habitats with increasingly levels of complexity from sub-catchments until entire hydrographic basins. Through these multiple spatial scales, local stream habitats form nested subsets of increasingly landscape scale and habitat size with varying contributions of both alpha and beta diversity for the regional diversity. Here, we aimed to test the relative importance of multiple nested hierarchical levels of spatial scales while determining alpha and beta diversity of caddisflies in regions with different levels of landscape degradation in a core Cerrado area in Brazil. We used quantitative environmental variables to test the hypothesis that landscape homogenization affects the contribution of alpha and beta diversity of caddisflies to regional diversity. We found that the contribution of alpha and beta diversity for gamma diversity varied according to landscape degradation. Sub-catchments with more intense agriculture had lower diversity at multiple levels, markedly alpha and beta diversities. We have also found that environmental predictors mainly associated with water quality, channel size, and habitat integrity (lower scores indicate stream degradation) were related to community dissimilarity at the catchment scale. For an effective management of the headwater biodiversity of caddisfly, towards the conservation of these catchments, heterogeneous streams with more pristine riparian vegetation found within the river basin need to be preserved in protected areas. Additionally, in the most degraded areas the restoration of riparian vegetation and size increase of protected areas will be needed to accomplish such effor
Aleitamento materno: benefícios e fatores associados
RESUMO: O aleitamento materno consiste no contato direto entre a mãe e o bebê para o exercício da amamentação e configura-se como um fator importante para o desenvolvimento saudável do lactente. Este trabalho tem como objetivo abordar os benefícios da amamentação para a criança e para a nutriz, bem como alguns fatores relacionados ao aleitamento materno. A metodologia utilizada foi um levantamento de cinco artigos em língua portuguesa e inglesa, publicados entre os anos de 2012 a 2015 no banco de dados SciELO, PubMED e Google Acadêmico. Os resultados demonstram inúmeros benefícios do aleitamento materno à saúde do lactente, bem como para a saúde da nutriz. Para a criança, a amamentação contribuiu para o desenvolvimento neurológico, nutricional, metabólico, orofacial adequados e à prevenção de doenças gastrointestinais, distúrbios nutricionais e alergias. Nas mães, os benefícios mais comuns foram prevenção de câncer de ovário, mama, prevenção de osteoporose e diminuição do risco de hemorragia pós-parto. Os resultados sobre os fatores secundários que se relacionam à prática do aleitamento estão relacionados a aspectos culturais, biológicos e psicossociais. Conclui-se, portanto, que a amamentação é essencial para o desenvolvimento imunológico e craniofacial do lactente, prevenção da obesidade e é relacionado com a redução da mortalidade neonatal. No entanto, é possível evidenciar barreiras biológicas, psicossociais e culturais que interferem na prática da amamentação. Posto isso, é necessário a ação conjunta de programas públicos e profissionais de saúde para ampliar o conhecimento da sociedade em geral acerca dos pontos positivos da amamentação.Palavras-chave:Aleitamento Materno. Benefícios. Amamentação
Fornecimento de leveduras vivas para novilhos Holandeses em confinamento com dieta 100% concentrada
Calves intended for meat production is an interesting alternative income. The objective was to evaluate the effect of providing probiotic Saccharomyces cerevisiae on the performance of Holstein steers in feedlot. The animals received 100% concentrated diet consisting of 80% of whole grain corn and 20% protein core, or without added yeast. The experimental design was completely randomized, with two treatments with eight replications. The use of probiotic did not significantly alter the feed conversion (average of 3.90 kg kg-1), consumption of daily dry matter (average 5.30 kg) and the dry matter intake per body weight (mean 2.32%). However, the daily weight gain of animals fed probiotic was higher, being 1.519 kg against 1.352 kg for the control group. The animals fed the yeast showed higher production cost of 7.14%, however, the profit margin was higher in 5.77% per animal. The use of probiotic acted effectively in improving animal performance, making it economically feasible.Destinar os bezerros oriundos de rebanhos leiteiros para a produção de carne é uma alternativa interessante de renda. O objetivo do trabalho foi avaliar o efeito do fornecimento de leveduras (Saccharomyces cerevisiae) sobre o desempenho de novilhos Holandeses em confinamento. Os animais receberam dieta 100% concentrada, composta de 80% de milho grão inteiro e 20% de núcleo proteico, adicionada ou não de levedura. O delineamento experimental foi inteiramente casualizado, composto por dois tratamentos com oito repetições. O uso do probiótico não alterou de forma significativa a conversão alimentar (média de 3,90 kg kg-1), o consumo de matéria seca diário (média de 5,30 kg) e o consumo de matéria seca em relação ao peso corporal (média de 2,32%). Porém, o ganho de peso médio diário dos animais que consumiram probiótico foi 12,35% maior, sendo de 1,519 kg contra 1,352 kg para o grupo controle. Os animais que consumiram a levedura apresentaram custo de produção maior em 7,14%, no entanto, a margem de lucro foi maior em 5,77% por animal. A utilização do aditivo de levedura em confinamento de bezerros holandeses aumenta o ganho de peso médio diário e o lucro por animal
RETINOBLASTOMA BILATERAL DE APARECIMENTO TARDIO: REVISÃO DE LITERATURA
This article aims to scan the current medical literature on the issues surrounding retinoblastoma, as although it is the most common ocular tumor in childhood, retinoblastoma can be diagnosed late, given its less specific signs and symptoms. In situations where the ocular examination is not performed correctly and other diagnostic work-up strategies are questionable, patients may be subjected to incorrect treatments. The most suggestive signs of the disease may not be present during medical evaluation. Delay in diagnosis of more than 6 months is associated with mortality of approximately 70%. Among the propaedeutic exams is fundoscopy, which allows a more accurate diagnosis in the face of suspicion and helps in monitoring the patient. This examination must be carried out monthly in the first year after the end of treatment, and quarterly thereafter. Additional imaging techniques are also important in the search for an assertive diagnosis and for the correct staging of the disease.Este artigo tem por objetivo realizar uma varredura da literatura médica vigente sobre as questões que envolvem o retinoblastoma, pois embora seja o tumor ocular mais comum na infância, o retinoblastoma pode ser diagnosticado de forma tardia, tendo em vista que sinais e sintomas menos específicos. Em situações em que o exame ocular não é realizado corretamente e as demais estratégias de propedêutica diagnóstica são questionáveis, os pacientes podem ser submetidos a tratamentos incorretos. Os sinais mais sugestivos da doença podem não estar presentes durante a avaliação médica. O atraso no diagnóstico superior a 6 meses está associado à mortalidade de aproximadamente 70%. Dentre os exames propedêuticos tem-se a fundoscopia, a qual permite um diagnóstico mais preciso diante da suspeita e auxilia no acompanhamento do paciente. Esse exame deve ser efetuado de forma mensal no primeiro ano após o término do tratamento, e posteriormente, trimestralmente. As técnicas de imagem adicionais também são importantes na busca de um diagnóstico assertivo e para o estadiamento correto da doença
HBM4EU chromates study - Overall results and recommendations for the biomonitoring of occupational exposure to hexavalent chromium
Exposure to hexavalent chromium [Cr(VI)] may occur in several occupational activities, e.g., welding, Cr(VI) electroplating and other surface treatment processes. The aim of this study was to provide EU relevant data on occupational Cr(VI) exposure to support the regulatory risk assessment and decision-making. In addition, the capability and validity of different biomarkers for the assessment of Cr(VI) exposure were evaluated. The study involved nine European countries and involved 399 workers in different industry sectors with exposures to Cr(VI) such as welding, bath plating, applying or removing paint and other tasks. We also studied 203 controls to establish a background in workers with no direct exposure to Cr(VI). We applied a cross-sectional study design and used chromium in urine as the primary biomonitoring method for Cr(VI) exposure. Additionally, we studied the use of red blood cells (RBC) and exhaled breath condensate (EBC) for biomonitoring of exposure to Cr(VI). Personal measurements were used to study exposure to inhalable and respirable Cr(VI) by personal air sampling. Dermal exposure was studied by taking hand wipe samples. The highest internal exposures were observed in the use of Cr(VI) in electrolytic bath plating. In stainless steel welding the internal Cr exposure was clearly lower when compared to plating activities. We observed a high correlation between chromium urinary levels and air Cr(VI) or dermal total Cr exposure. Urinary chromium showed its value as a first approach for the assessment of total, internal exposure. Correlations between urinary chromium , Cr(VI) in EBC and Cr in RBC were low, probably due to differences in kinetics and indicating that these biomonitoring approaches may not be interchangeable but rather complementary. This study showed that occupational biomonitoring studies can be conducted successfully by multi-national collaboration and provide relevant information to support policy actions aiming to reduce occupational expo-sure to chemicals
Legacy of Amazonian Dark Earth soils on forest structure and species composition
This is the final version. Available from the publisher via the DOI in this record.Aim: Amazonian forests predominantly grow on highly weathered and nutrient poor soils. Anthropogenically enriched Amazonian Dark Earths (ADE), traditionally known as Terra Preta de Índio, were formed by pre-Columbian populations. ADE soils are characterized by increased fertility and have continued to be exploited following European colonization. Here, we evaluated the legacy of land-use and soil enrichment on the composition and structure in ADE and non-ADE (NDE) forests. Location: Eastern and southern Amazonia. Time period: Pre-Columbia – 2014. Methods: We sampled nine pairs of ADE and adjacent NDE forest plots in eastern and southern Amazonia. In each plot, we collected soil samples at 0–10 and 10–20 cm depth and measured stem diameter, height, and identified all individual woody plants (palms, trees and lianas) with diameter ≥ 10 cm. We compared soil physicochemical properties, vegetation diversity, floristic composition, aboveground biomass, and percentage of useful species. Results: In the nine paired plots, soil fertility was significantly higher in ADE soil. We sampled 4,191 individual woody plants representing 404 species and 65 families. The floristic composition of ADE and NDE forests differed significantly at both local and regional levels. In southern Amazonia, ADE forests had, on average, higher aboveground biomass than other forests of the region, while in eastern Amazonia, biomass was similar to that of NDE forests. Species richness of both forest types did not differ and was within the range of existing regional studies. The differences in composition between large and small diameter tree recruits may indicate long-term recovery and residual effects from historical land-use. Additionally, the proportion of edible species tended to be higher in the ADE forests of eastern and southern Amazonia. Main conclusions: The marked differences in soil fertility, floristic composition and aboveground biomass between ADE and NDE forests are consistent with a small-scale long-term land-use legacy and a regional increase in tree diversity
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