Bark thermal protection level of four tree species and the relationship between bark architecture and heat transfer [Nível de proteção térmica da casca de quatro espécies lenhosas e a relação da arquitetura da casca com a transferência de calor]
do Vale A.T.,University of Brasilia |
Elias P.S.,Portal Brazil
Ciencia Florestal | Year: 2014
The bark is a protective tissue of the tree-cambium and the exposition to temperatures above 60°C for 1 to 2 minutes, which is one of the main factors that cause tree mortality in forest fires. In this research, it was studied the bark protection levels of Eucalyptus grandis and of three tree-species of ‘cerrado’: Pterodon pubescens, Sclerolobium paniculatum and Vochysia thyrsoidea and the effects of these tree bark architectures in heat transfer. Samples were taken from bark panels representing five trees of each species. The time of heat exposure required to damage the tree-cambium until temperature reached 60°C (lethal temperature) and the roughness coefficient (architecture) was estimated by the ratio between the actual area and the nominal sample area. The Sclerolobium paniculatum, with thinner bark, showed the shortest time and Eucalyptus grandis and Pterodon pubescens the longer time. The only exception was Vochysia thyrsoidea with a greater thickness and showed the shortest times. The tree species with the highest correlation between time and the total thickness was Sclerolobium paniculatum (r = 0,93). Pterodon pubescens and Eucalyptus grandis showed r = 0,73 and r = 0,56, respectively and Vochysia thyrsoidea presented the lower correlation coefficient (0,34). The highest roughness was observed for Vochysia thyrsoidea, which was significantly different from the other tree-species. However, the correlation coefficient between time and surface roughness was not significant for all tree-species, which suggest that theincrease of the roughness did not affect the heat transfer through the bark. © 2014 Universidade Federal de Santa Maria. All rights reserved.
de Oliveira P.C.P.,Portal Brazil |
Gloaguen T.V.,CETEC |
Goncalves R.A.B.,CETEC |
Santos D.L.,Campus Universitario Of Cruz Das Almas
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2013
The objective of this study was to evaluate the yield of pumpkin (Cucurbita maxima Duch. Coroa IAC) irrigated with treated domestic wastewater. The study was conducted in a completely randomized design with five treatments and four replications. The treatments were: T1- irrigation depth of 150% of crop water demand; T2- irrigation depth of 150% of crop water demand with application of CaSO4in soil; T3- irrigation depth of 100% of crop water demand; T4- irrigation depth of 100% of crop water demand with application of CaSO4in soil and T5- control (without irrigation). The parameters evaluated were: crop yield, weight andnumber offruits, their physico-chemical characteristics and potential contamination by pathogens in water. Significant differences in productivity, yield and number of fruits were identified between the control and all other treatments. The physico-chemical characteristics were similar in all treatments. Thermo tolerant coliforms were detected only on the surface of the fruit, but at levels below theminimum standards established by the sanitary legislation.
Neto M.M.,Portal Brazil
Gestao e Producao | Year: 2011
This study focuses on the power dynamic of a particular space: Brazilian Airlines Companies. Applying the concepts of Organizational Theory and Economic Sociology, it was possible to analyze the strategies of TAM and GOL airlines, which are companies that dominate the aviation market. Gathering institutional information from those companies, from government entities which control those companies' activities, and also from the business media, this study focused on indicating the social actors responsible for structuring these dominant companies. Both companies operate in the aviation market , but they also operate in the stock market. GOL business model, particularly the use of private equities tools, can be considered a determinant factor for the new configuration of this industry. In terms of financial market, TAM adopts similar strategy to that adopted by GOL. The recent aviation crisis and the financial crisis of 2008 strongly affected both companies, particularly their stock market value.
de Almeida E.C.E.,Federal University of Rio Grande do Sul |
de Almeida E.C.E.,Portal Brazil |
Guimaraes J.A.,Federal University of Rio Grande do Sul
Scientometrics | Year: 2013
This article identifies scientific fields in Brazil that have been generating new knowledge, their evolution, tendencies and the relationship between scientific production and the National Postgraduate Program (Programa Nacional de Pós-Graduação-PNPG). It works with review articles and assesses: (a) articles published as reviews by international databases; (b) the growth of Brazilian participation in that context; (c) institutional participation; (d) the predominant fields of knowledge; (e) the most productive authors, and (f) periodicals that published the greatest number of review articles by Brazilian authors. The 5,348 review articles published between 2000 and 2009 were made available in 1,309 scientific publications, and the fields that published the most reviews were Pharmacology, Chemistry, Neurosciences, Biochemistry and Molecular Biology, Psychiatry, Neurology, Endocrinology and Internal Medicine. The reviews were produced by 27,096 authors under the auspices of 20 institutions which, together, answer for 95 % of the Brazilian production, and are public, excepting for the Pontifícia Universidade Católica do Rio Grande do Sul (PUC-RS). In the international scenario, we find that 31 countries are responsible for 90.11 % of the total scientific production and 94.08 % of the review articles. To establish a comparison between Brazil and its closest competitors, these countries can be classified arbitrarily in three groups: (1) countries with a large number of review articles (>3100), an average number of citations above 18, and an h-index greater than 95; (2) countries with a significant production of articles (between 2,000 and 3,000), average number of citations between 12 and 17, and an h-index below 95. Brazil is in the third group, (3) formed by countries with a lower level of production and the two qualitative indicators at opposite poles: the average of citations on a par with the first group (>18) and h-indexes like those of the second group (<95). © 2013 Akadémiai Kiadó, Budapest, Hungary.
Romero G.Q.,Sao Paulo State University |
Romero G.Q.,Portal Brazil |
Srivastava D.S.,University of British Columbia
Journal of Animal Ecology | Year: 2010
1. Ecosystems may affect each other through trophic interactions that cross ecosystem boundaries as well as via the transfer of subsidies, but these effects can vary depending on the identity of species involved in the interaction. 2. In this study, we manipulated two terrestrial bromeliad-living spider species (Aglaoctenus castaneus, Corinna gr. rubripes) that have variable hunting modes, to test their individual and combined effects on aquatic invertebrate community structure and ecosystem processes (i.e. decomposition rate and nitrogen cycling). We predicted that these terrestrial predators can affect aquatic invertebrates and nutrient dynamics within water-filled bromeliads. 3. Aglaoctenus spiders reduced the richness, abundance and biomass of aquatic insect larvae via consumptive or non-consumptive effects on ovipositing terrestrial adults, but effects of the two spider species in combination were usually the linear average of their monoculture effects. In contrast, invertebrates with entirely aquatic life cycles were unaffected or facilitated by spiders. Spiders did not affect either net detritivore biomass or the flux of detrital nitrogen to the bromeliad. Instead, Corinna spiders contributed allochthonous nitrogen to bromeliads. 4. Our results provide the novel observations that predators in one ecosystem not only directly reduce taxa whose life cycles cross-ecosystem boundaries, but also indirectly facilitate taxa whose life cycles are entirely within the second ecosystem. This compensatory response between crossecosystem and within-ecosystem taxa may have led to an attenuation of top-down effects across ecosystem boundaries. In addition, our results add to a growing consensus that species identity is an important determinant of community structure and ecosystem functioning. Thus, the composition of both terrestrial and aquatic food webs may affect the strength of cross-ecosystem interactions. © 2010 TheAuthors. Journal compilation © 2010 British Ecological Society.