114 research outputs found
Applications in anthropometrical variables posts joineries work in the south of the Espírito Santo
Esta pesquisa foi realizada em três marcenarias, sendo uma no município de Alegre e duas no município de Jerônimo Monteiro, todas localizadas no sul do Espírito Santo no período de agosto de 2009 a julho de 2010, e teve os seguintes objetivos: avaliar as condições antropométricas dos trabalhadores e correlacioná-las com as potencialidades e imperfeições de nove máquinas utilizadas comumente nesses empreendimentos. Os resultados mostraram que os coeficientes de variação dos dados indicam uma distribuição homogênea ou média dispersão de distribuição de todos os valores encontrados, à exceção da variável idade, que apresentou distribuição heterogênea. Todas as alturas das bancadas dos postos de trabalho avaliados se mantiveram, em média, 14,5 cm abaixo do recomendado (99,0 cm), na maioria dos postos de trabalho. Com base nesses dados, recomendou-se uma reorganização ergonômica do trabalho, com alturas ideais das bancadas das máquinas e posicionamento e acessos ideais dos postos de trabalho, sendo sugerido o uso de EPI (Equipamento de Proteção Individual) de maior profilaxia e especificidade ao trabalhador.This research was carried through in three joineries, being one in the city of Alegre and two in the city of Jerônimo Monteiro, located in the south of the Espirito Santo, Brazil, in the period of August of 2009 the July of 2010 and had the following objectives: to evaluate the anthropometric conditions of the workers and to common correlate them with the potentialities and imperfections of nine machines used common in these joineries. The results had indicated that the coefficients of variation of the data had indicated a homogeneous distribution or average dispersion of distribution of all the found values, to the exception of the changeable age that presented heterogeneous distribution. All the heights of group of benches of the evaluated ranks of work if had kept, on average, 14,5 cm below of the recommended one (99,0 cm), in the majority of the work ranks. Through of these data sent regards an ergonomic reorganization of the work, ideal heights of group of benches of the machines, positioning and ideal accesses of the work ranks and were suggested the use of EPIs (Equipment of Individual Protection) of bigger Prophylaxis and specific to the worker
EXTRATO DE MAMONA COMO MANIPULADOR DA FERMENTAÇÃO RUMINAL
Objetivou-se investigar os efeitos da adição do extrato de farelo de mamona (EFM) sobre o perfil da fermentação ruminal in vitro em dietas com alto e baixo teor de forragem. Utilizou-se ensaio de incubação ruminal in vitro com dois controles, um negativo (sem aditivo) e um positivo (monensina sódica) e EFM liofilizado (20, 40 e 60 mg/frasco). Em condições de alto teor de forragem na dieta, a adição do EFM aumentou o pH do meio e a concentração de acetato, reduziu a produção de gás, mas não afetou a produção de gás por unidade de matéria seca (MS) digerida em relação ao tratamento controle. Em comparação com monensina sódica, o EFM reduziu as concentrações de propionato e amônia e aumentou a produção de gás por unidade de MS digerida. Em condições de baixo teor de forragem, a adição do EFM reduziu o pH e potencial redox do meio em relação ao tratamento controle. Em comparação com a monensina sódica, o EFM reduziu o pH do meio e a produção total de gás, mas não afetou a produção de gás por unidade de MS digerida. O extrato de farelo de mamona destoxificado não apresenta potencial como manipulador da fermentação ruminal.Palavras-chave: amônia; digestibilidade; eficiência; metano. CASTOR BEAN EXTRACT AS A MANIPULATOR OF RUMINAL FERMENTATION ABSTRACT: Effects of the castorbean meal extract (CME) on ruminal in vitro were investigate in high and low forage diet conditions. For each dietary condition, one in vitro ruminal incubation experiment was conducted in a completely randomized design, with nine repetitions per treatment (three animal inoculum donators and three 48 hors-incubations). In high forage diet, CME increased ruminal pH acetate concentration, reduced gas production, but it did not affect the gas production per unit of digested dry matter (DM), in relation to control treatment. Compare to monensin sodium, CME reduced propionate and ammonia concentrations and increased gas production per unit of digested DM, indicating that CME reduces ruminal energetic efficiency. In low forage diet, CME reduced pH and redox potential compare to control. Compare to monensin sodium, CME reduced pH and gas production, but it did not affect gas production per unit of digested DM. Castorbean meal extract does not present potential as manipulator of the ruminal fermentation.Keywords: ammonia; digestibility; efficiency; methane
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Direct evidence for phosphorus limitation on Amazon forest productivity
The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.The authors acknowledge funding from the UK Natural Environment Research Council (NERC), grant number NE/L007223/1. This is publication 850 in the technical series of the BDFFP. C.A.Q. acknowledges the grants from Brazilian National Council for Scientific and Technological Development (CNPq) CNPq/LBA 68/2013, CNPq/MCTI/FNDCT no. 18/2021 and his productivity grant. C.A.Q., H.F.V.C., F.D.S., I.A., L.F.L., E.O.M. and S.G. acknowledge the AmazonFACE programme for financial support in cooperation with Coordination for the Improvement of Higher Education Personnel (CAPES) and the National Institute of Amazonian Research as part of the grants CAPES-INPA/88887.154643/2017-00 and 88881.154644/2017-01. T.F.D. acknowledges funds from FundacAo de Amparo a Pesquisa do Estado de SAo Paulo (FAPESP), grant 2015/50488-5, and the Partnership for Enhanced Engagement in Research (PEER) programme grant AID-OAA-A-11-00012. L.E.O.C.A. thanks CNPq (314416/2020-0)
Intra-radicular dentin treatments and retention of fiber posts with self-adhesive resin cements
The aim of this study was to evaluate the effect of treating intraradicular dentin with irrigating solutions on the retention of glass-fiber posts luted with self-adhesive resin cement. Bovine incisors were endodontically treated, and 9-mm-deep postholes were prepared. Before inserting the cement, the root canals were irrigated with various solutions: 11.5% polyacrylic acid for 30 s, 17% EDTA for 60 s, or 5% NaOCl for 60 s, respectively. Irrigation with distilled water was used in the control group. After all specimens had been rinsed with distilled water, the excess moisture was removed and the posts were luted using either BisCem (Bisco) or RelyX Unicem clicker (3M ESPE). Seven days after luting, the specimens were sectioned transversally into 1-mm-thick slices, which were submitted to push-out testing on a mechanical testing machine. Bond strength data (n = 6 per group) were analyzed by two-way ANOVA and Student-Newman-Keuls' test (α = 0.05). For Unicem, EDTA showed lower bond strength than the other solutions, which had similar results. For BisCem, EDTA showed higher bond strength than the other treatments, while application of NaOCl yielded higher bond strength than polyacrylic acid whereas the control group had intermediate results. In conclusion, irrigating root canals before insertion of self-adhesive resin cements, especially EDTA, might interfere with retention of the fiber posts
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Unidad de excelencia María de Maeztu CEX2019-000940-MAim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
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
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