39 research outputs found
Padrões da área do xilema ativo em espécies florestais amazônicas na região de Manaus (Am)
Hydrological processes in forest stands are mainly influenced by the stand forming plant species and their physiological characteristics. Distinct water use patterns of certain species can lead to limitation in forest management practices. Most tropical studies determining the water use pattern of forest plant species were conducted almost exclusively outside Brazil. Thus, the purpose of this thesis was to obtain sapwood area patterns through dye immersions in forest species near the city of Manaus – Amazonas. The data of sap wood area was associated with the ecology of the collected tree species and açai palm individuals (Euterpe precatoria), wood anatomy, diameter at breast height (DBH), height and volume. Allometric models to determine sapwood area were applied. Another section of this thesis focused on analyzing hydraulic conductivity at different heights of açai palms and hydraulic conductivity between different tree species. Finally, compare results obtained between trees and palms. Data were collected at the ZF-2 experimental field site on km 18 of the vicinal road. 34 sample trees were chosen randomly in an area of approximately 6 ha. Tree height was measured after cutting the tree. Stem sections of the harvested trees were taken to the laboratory to be immersed in indigo carmine dye solution until coloring was apparent on the upper side of the log. The colored cross section was assumed to be the conducting tissue of the sapwood and was measured along with diameter. Species were identified through anatomical wood characteristics. Vessel diameter, frequency and length were measured in a specialized wood laboratory. Sapwood patterns differed between and within species although all were diffuse porous. The allometric model was obtained through linear and non-linear regressions. The best relationship and model fit was obtained between sapwood area and DBH with a non-linear model. The null relationship and worse model fil was with vessel frequency that didn’t present any apparent influence over sapwood area. Model fits didn’t present high statistical parameters, but excluding vessel diameter and frequency, all relationships were positive and conclusive. These low statistical parameters can be explained through certain species characteristics, microclimate and ecological factors. Hydraulic conductivity between the sampled trees was very distinct with values varying from 0.09 to 24 kg m-1s MPa-1. These differences were also explained through species autoecology and microclimate. Ten açai palms were collected near the same study area as trees and were submitted to the same coloring process and wood anatomy analysis. Palms presented same sapwood pattern within and between species. Hydraulic conductivity was different in the heights analyzed. Hydraulic conductivity in the base of the crown was higher than in the base of the trunk, due to the high density of vessels in a small cross-section or sapwood area in this height. Palm trees also presented a positive relationship with DBH. When comparing trees and palms, we observed that trees and palms share the positive relationship with DBH, but presented different sapwood patterns and hydraulic conductivity values. Thus, this study showed how species present different characteristics that can influence water transport, but have common variables that can maintain the ecosystem balance they grow and assist in the estimation of forest stand transpiration.Processos hidrológicos em povoamentos florestais são influenciados, principalmente, pelas espécies vegetais ocorrentes e suas características fisiológicas. Padrões de uso de água distintos de determinadas espécies podem levar a uma limitação de práticas de manejo florestal. A maioria dos estudos realizados em florestas tropicais sobre padrões hidráulicos das plantas foram conduzidos fora do Brasil. Com isto, o objetivo desta dissertação foi determinar padrões da área do xilema ativo, por meio de imersões em corante, de espécies florestais próximas à cidade de Manaus- Amazonas. Os dados da área do xilema ativo foram relacionados à ecologia de espécies arbóreas e indivíduos da palmeira açaí (Euterpe precatoria) coletados, à anatomia da madeira, diâmetro a altura do peito (DAP), altura total e volume. Modelos alométricos foram aplicados para a estimativa da área do xilema ativo. Outra seção desta dissertação focou na análise da condutividade hidráulica (Ks) em diferentes alturas de palmeiras açaí e entre diferentes espécies arbóreas. E finalmente, comparar os resultados de ambos os grupos funcionais. Dados foram coletados na estação experimental ZF-2 em uma área de aproximadamente 6 ha situada no km 18 da estrada vicinal. 34 árvores foram escolhidas aleatoriamente. Altura total foi mensurada após a derrubada. Seções das árvores amostradas foram levadas para o laboratório onde foram imersas em uma solução corante de indigo carmine até que a coloração fosse observada na face superior da tora. Assumiu-se que a parte colorida de azul na seção transversal correspondia à área do xilema ativo e com isto foi medida juntamente com o diâmetro do indivíduo. Espécies foram identificadas através dos atributos anatômicos da madeira. Diâmetro, frequência e comprimento de elemento de vaso foram mensurados em um laboratório especializado. Padrões da área condutiva se diferenciaram entre e dentro das espécies, apesar de todas serem de porosidade difusa. O modelo alométrico foi desenvolvido por meio de regressões lineares e não-lineares. O melhor ajuste e relação foi obtido entre área do xilema ativo e DAP com modelo não-linear. O pior ajuste e relação foram obtidos com a variável frequência de vaso, que não apresentou relação ou influência aparente sobre área do xilema ativo. Os ajustes não apresentaram elevados parâmetros estatísticos, mas com exceção de diâmetro e frequência de vaso, todas as correlações foram positivas e conclusivas. Estes baixos parâmetros estatísticos podem ser explicados por determinadas características das espécies, microclima e fatores ecológicos. Ks entre as árvores amostradas foi bastante distinta com valores variando entre 0,09 e 24 kg m-1s MPa-1. Estas diferenças também foram explicadas por meio da autoecologia das espécies e microclima. Dez palmeiras açaí foram coletadas próximas à área de estudo das árvores e foram submetidas ao mesmo processo de coloração e análise anatômica da madeira. As palmeiras apresentaram área do xilema ativo com padrões similares entre e dentro das espécies. Ks foi diferente nas alturas analisadas. Ks na base da copa foi mais elevada do que na base do fuste, devido à alta frequência de vasos presentes na seção transversal e área do xilema ativa reduzida presente nesta altura. As palmeiras também apresentaram uma relação positiva com DAP. Ao comparar árvores com palmeiras, observou-se que árvores e palmeiras compartilham a mesma relação positiva com DAP, porém apresentam diferentes padrões de área condutiva e valores de Ks. Com isto, este estudo mostrou como espécies apresentam características diferentes que podem influenciar transporte de água, mas possuem variáveis em comum que contribuem com o equilibro do ecossistema em que vivem e podem também auxiliar na estimativa de transpiração florestal do povoamento
Plant-Atmosphere Responses to Wet Canopy Conditions in a Mature Tropical Forest
Spatial and temporal variation in wet canopy conditions following precipitation events can influence processes such as transpiration and photosynthesis, which can be further enhanced as upper canopy leaves dry more rapidly. As part of a larger study aimed at improving land-surface modeling in a wet tropical forest of Costa Rica, this dissertation: I) compared transpiration among trees with exposed and shaded crowns under various leaf wetness conditions; II) evaluated responses of seven tropical and three semiarid savanna plant species to simulated leaf wetness; and III) tested stomatal and canopy conductance model performance while canopies were wet. To address these goals, I mainly relied on 43 sap flux sensors (Js), gas exchange measurements under dry and wet conditions, and one year and a half of micrometeorological measurements from a 40-m tower inside a mature rainforest plot.
Overstory trees (13% of the plot) contributed ~76% to total stand transpiration. Transpiration and Js was driven by vapor pressure deficit and solar radiation, but leaf wetness had a significant role by reducing as much as 28%. Dry days had equal quantities of Js between overstory and midstory trees; while on wet days, all trees had low Js rates. Meanwhile, photosynthetic responses (Anet) while leaves were wet varied greatly among species, but all plants maintained a baseline of activity. Anet responses, among all ten species, varied between -48% and +21%, when compared to their dry condition performance. Due to the canopy and atmospheric complexity of the study site, most canopy models tested did not depict leaf wetness periods appropriately. Even iii during dry days, low vapor pressure deficits interfered with model accuracy. Also, intermittent rain, during semi-dry and wet days, caused large fluctuations in canopy and stomatal conductance estimates, especially between shaded and sunlit leaves.
Thus, this dissertation found compelling evidence that leaf wetness may partially or substantially suppress physiological responses in function of leaf anatomy and intercanopy microclimate. Therefore, further studies on tropical plant traits across a wide range of species, and on leaf-level gas exchange and sap flow measurements are needed to improve the accuracy of climatic modelling of wet tropical ecosystems
Precipitation mediates sap flux sensitivity to evaporative demand in the neotropics
Transpiration in humid tropical forests modulates the global water cycle and is a key driver of climate regulation. Yet, our understanding of how tropical trees regulate sap flux in response to climate variability remains elusive. With a progressively warming climate, atmospheric evaporative demand [i.e., vapor pressure deficit (VPD)] will be increasingly important for plant functioning, becoming the major control of plant water use in the twenty-first century. Using measurements in 34 tree species at seven sites across a precipitation gradient in the neotropics, we determined how the maximum sap flux velocity (vmax) and the VPD threshold at which vmax is reached (VPDmax) vary with precipitation regime [mean annual precipitation (MAP); seasonal drought intensity (PDRY)] and two functional traits related to foliar and wood economics spectra [leaf mass per area (LMA); wood specific gravity (WSG)]. We show that, even though vmax is highly variable within sites, it follows a negative trend in response to increasing MAP and PDRY across sites. LMA and WSG exerted little effect on vmax and VPDmax, suggesting that these widely used functional traits provide limited explanatory power of dynamic plant responses to environmental variation within hyper-diverse forests. This study demonstrates that long-term precipitation plays an important role in the sap flux response of humid tropical forests to VPD. Our findings suggest that under higher evaporative demand, trees growing in wetter environments in humid tropical regions may be subjected to reduced water exchange with the atmosphere relative to trees growing in drier climates
A Plant Proteinase Inhibitor from Enterolobium contortisiliquum Attenuates Pulmonary Mechanics, Inflammation and Remodeling Induced by Elastase in Mice
Proteinase inhibitors have been associated with anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment for emphysema. Our aim was to evaluate the effects of a plant Kunitz proteinase inhibitor, Enterolobium contortisiliquum trypsin inhibitor (EcTI), on several aspects of experimental elastase-induced pulmonary inflammation in mice. C57/Bl6 mice were intratracheally administered elastase (ELA) or saline (SAL) and were treated intraperitoneally with EcTI (ELA-EcTI, SAL-EcTI) on days 1, 14 and 21. On day 28, pulmonary mechanics, exhaled nitric oxide (ENO) and number leucocytes in the bronchoalveolar lavage fluid (BALF) were evaluated. Subsequently, lung immunohistochemical staining was submitted to morphometry. EcTI treatment reduced responses of the mechanical respiratory system, number of cells in the BALF, and reduced tumor necrosis factor- (TNF-), matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-12 (MMP-12), tissue inhibitor of matrix metalloproteinase (TIMP-1), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS)-positive cells and volume proportion of isoprostane, collagen and elastic fibers in the airways and alveolar walls compared with the ELA group. EcTI treatment reduced elastase induced pulmonary inflammation, remodeling, oxidative stress and mechanical alterations, suggesting that this inhibitor may be a potential therapeutic tool for chronic obstructive pulmonary disease (COPD) management.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Univ Sao Paulo, Sch Med, Dept Clin Med, BR-01246903 Sao Paulo, BrazilHosp Sirio Libanes, Phys Therapy Dept, BR-01308050 Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Biosci, BR-09972270 Diadema, BrazilUniv Fed Sao Paulo, Dept Biochem, BR-09972270 Diadema, BrazilUniv Fed Sao Paulo, Dept Biosci, BR-09972270 Diadema, BrazilUniv Fed Sao Paulo, Dept Biochem, BR-09972270 Diadema, BrazilWeb of Scienc
Formação inicial de professores de educação física: um olhar para o estágio curricular supervisionado
Introdução: analisar o papel do Estágio Curricular Supervisionado (ECS) na formação inicial de professores de Educação Física implica em entender que o conhecimento pedagógico especializado se legitima na prática, e, mais do que no conhecimento das disciplinas, compreende os procedimentos de transmissão, de forma complexa e desafiadora, dos conhecimentos da cultura corporal de movimento. Nesse sentido, esta Objetivo: verificar, a partir da perspectiva de estudantes-estagiários, a organização e relevância da realização do ECS, bem como, a compreensão didático-pedagógica que esses apresentam com relação à realização desse primeiro contato com o ambiente escolar. Métodos: participaram deste estudo qualitativo, trinta e cinco acadêmicos de uma instituição pública do norte do estado do Paraná/Brasil. As informações levantadas decorreram dos relatórios finais apresentados na disciplina de ECS I. Resultados: da análise das informações coletadas emergiram-se duas categorias de apresentação dos resultados: a) organização e estrutura da disciplina de ECS I e b) significados do ECS I para a formação docente. Na primeira categoria, os participantes destacam que a carga horária das ações do ECS possui caráter excessivo frente aos demais componentes curriculares, porém entendem que tal processo se faz necessário pois possibilita uma efetivação da relação teoria e prática. Na segunda, revelam que o ECS auxilia na reflexão contínua do futuro professor para com o exercício da sua profissão, traduz-se em uma ação educativa a partir da práxis, torna-se meio de socialização profissional, e, possibilita a reflexão das amarras entre a profissão e a escola. Conclusão: entende-se que o estágio se configura como um dos componentes essenciais na lapidação do processo inicial de construção do ser professor em suas mais diversas facetas para o contexto escolar dentro da formação de professores de Educação Física.
ABSTRACT. Initial training of physical education teachers: a look at the supervised practicum. Background: analyze the role of the Supervised Practicum (SP) at the initial training of the Physical Education Teachers implies understanding that specialized pedagogical knowledge is legitimated in practice and, more than the knowledge of the subjects, comprehends the procedures of transmission of the knowledge of body movement culture, in a complex and challenging way. Objective: to verify, from the perspective of student-trainees, the organization and relevance of the SP, as well as the didactic-pedagogical understanding that the students present regarding the accomplishment of this first contact with the school environment. Methods: Thirty-five students from a public institution in the north of the state of Paraná/Brazil participated in this qualitative study. The collected information came from the final reports presented in the SP I subject. Results: from the analysis of the information collected, two categories of results were presented: a) organization and structure of the SP I subject and b) SP I significance for teacher training. In the first category, the participants emphasize that the workload of the SP actions is excessive compared to the other curricular components, but they understand that this process is necessary because it allows an effective relationship between theory and practice. In the second, they reveal that the SP helps in the continuous reflection of the future teacher towards the exercise of their profession, it is translated into an educational action from the praxis, it becomes a means of professional socialization, and, it allows the reflection of the relations between the profession and the school. Conclusion: it is understood that the practicum is one of the essential components in the stoning of the initial process of construction of being a teacher in its most diverse facets for the school context within the training of Physical Education teachers
Global transpiration data from sap flow measurements: the SAPFLUXNET database
Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land?atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets,while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes.Fil: Poyatos, Rafael. Universitat Autònoma de Barcelona; EspañaFil: Granda, Víctor. Universitat Autònoma de Barcelona; EspañaFil: Flo, Víctor. Universitat Autònoma de Barcelona; EspañaFil: Adams, Mark A.. Swinburne University of Technology; Australia. University of Sydney; AustraliaFil: Adorján, Balázs. University of Debrecen; HungríaFil: Aguadé, David. Universitat Autònoma de Barcelona; EspañaFil: Aidar, Marcos P. M.. Institute of Botany; BrasilFil: Allen, Scott. University of Nevada; Estados UnidosFil: Alvarado Barrientos, M. Susana. Instituto de Ecología A.C.; MéxicoFil: Anderson Teixeira, Kristina J.. Smithsonian Tropical Research Institute; PanamáFil: Aparecido, Luiza Maria. Arizona State University; Estados Unidos. Texas A&M University; Estados UnidosFil: Arain, M. Altaf. McMaster University; CanadáFil: Aranda, Ismael. National Institute for Agricultural and Food Research and Technology; EspañaFil: Asbjornsen, Heidi. University of New Hampshire; Estados UnidosFil: Robert Baxter. Durham University; Reino UnidoFil: Beamesderfer, Eric. McMaster University; Canadá. Northern Arizona University; Estados UnidosFil: Carter Berry, Z.. Chapman University; Estados UnidosFil: Berveiller, Daniel. Université Paris Saclay; Francia. Centre National de la Recherche Scientifique; FranciaFil: Blakely, Bethany. University of Illinois at Urbana-Champaign; Estados UnidosFil: Boggs, Johnny. United States Forest Service; Estados UnidosFil: Gil Bohrer. Ohio State University; Estados UnidosFil: Bolstad, Paul V.. University of Minnesota; Estados UnidosFil: Bonal, Damien. Université de Lorraine; FranciaFil: Bracho, Rosvel. University of Florida; Estados UnidosFil: Brito, Patricia. Universidad de La Laguna; EspañaFil: Brodeur, Jason. McMaster University; CanadáFil: Casanoves, Fernando. Centro Agronómico Tropical de Investigación y Enseñanza; Costa RicaFil: Chave, Jérôme. Université Paul Sabatier; FranciaFil: Chen, Hui. Xiamen University; ChinaFil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; Argentin
Educomunicação e diversidade: tecendo saberes
Com esta publicação Educomunicação e Diversidade: Tecendo Saberes, a Associação Brasileira de Pesquisadores e Profissionais de Educomunicação socializa uma importante contribuição para o aprofundamento e aprimorando de estudos e práticas educativas e comunicativas numa perspectiva de respeito às diversidades.
A publicação está estruturada em quatro partes, a saber: I. Educomunicação e Políticas para a Cidadania; II. Práxis Educomunicativa: o principio da indissociabilidade entre ensino-pesquisa-extensão; III. Educomunicação e Formação em EAD; IV – Mediação Tecnológica. Trata-se, assim, de um trabalho coletivo que contém 19 capítulos onde contribuem 35 autores e coautores.
Eis uma publicação que se destina não somente aos educomunicadores, mas a todos os que assumem o desafio de pensar numa outra forma possível de educar e de comunicar, mais colaborativa, intercultural, criativa e emancipatória, menos colonizadora e arrogante. Desejamos à leitora-interlocutora, ou ao leitor-interlocutor, uma leitura prazerosa, crítica e problematizadora dessa publicação que se apresenta como um ensaio, mas com a pretensão e o potencial de contribuir para o avanço dos estudos em torno do campo de interface entre Comunicação e Educação, sempre com o imprescindível respeito às diversidades