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Search Results: 1 - 10 of 600306 matches for " E.A.;Silva "
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Avalia o da surdez ocupacional
Silva A.A.,Costa E.A. da
Revista da Associa??o Médica Brasileira , 1998,
Abstract:
Estudos anat?micos de folhas de espécies de plantas daninhas de grande ocorrência no Brasil: IV - Amaranthus deflexus, Amaranthus spinosus, Alternanthera tenella e Euphorbia heterophylla
Ferreira, E.A.;Procópio, S.O.;Silva, E.A.M.;Silva, A.A.;Rufino, R.J.N.;
Planta Daninha , 2003, DOI: 10.1590/S0100-83582003000200012
Abstract: this research aimed to study the leaf anatomy of the weed species amaranthus deflexus, amaranthus spinosus, alternanthera tenella and euphorbia heterophylla, widely known in brazil, to acquire a better understanding of the barriers each species imposes to herbicide penetration, and to other substances used for leaf spraying. completely expanded leaves from the third to the fifth nodes were collected from spontaneous plants in the field. three samples approximately 1cm2, were removed from the medium portion of the leaves, from each species. these samples were used for structure, clarification and scanning-electron microscope observations. all species were amphistomatic. the potential major leaf barriers to herbicide penetration in a. deflexus and a. spinosus were, respectively, high cuticle thickness in the adaxial side and high cuticle thickness in both sides, respectively, whereas in a. tenella, high cuticle thickness on both sides, high content of epicuticular wax and high trichome density were the major potential barriers observed. e. heterophylla showed high content of the epicuticular wax, high latex glandular density and high cuticle thickness in the adaxial side as possible major barriers to herbicide penetration.
Qualidade de sementes de feij?o (Phaseolus vulgaris) após aplica??o do carfentrazone-ethyl em pré-colheita
Santos, J.B.;Ferreira, E.A.;Santos, E.A.;Silva, A.A.;Silva, F.M.;Ferreira, L.R.;
Planta Daninha , 2004, DOI: 10.1590/S0100-83582004000400019
Abstract: this study aimed to evaluate the effects of bean desiccation (talism? cultivar) with carfentrazone-ethyl on seed quality. desiccation was performed by applying 5 rates (0, 10, 30, 60 and 120 g ha-1) of carfentrazone-ethyl associated to three application times, 25, 30 and 35 days after flowering (daf). humidity loss was quantified two days after each application. harvest was performed eight days after each application, followed by determination of the weight of 100 seeds, and the proportion of seeds was classified as "small" (passed through sieve 14/64"), "medium" (retained in sieves 14/64" and 16/64") and "larger" (retained in sieves 16/64") and the germination test (gt). carfentrazone-ethyl application, at doses superior to 60 g ha-1 rates, 25 daf, accelerated seed humidity loss, affecting the size and weight of 100 seeds. desiccant application between 10 and 30 g ha-1 rates, 30 daf, provided better results, larger yield and seed quality without a negative effect on germination.
Estudos anat?micos de folhas de espécies de plantas daninhas: II - Bidens pilosa, Emilia sonchifolia, Ageratum conyzoides e Sonchus asper
Ferreira, E.A.;Procópio, S.O.;Silva, E.A.M.;Silva, A.A.;Rufino, R.J.N.;
Planta Daninha , 2002, DOI: 10.1590/S0100-83582002000300001
Abstract: this research aimed to study leaf anatomy in the widely common brazilian weed species bidens pilosa, emilia sonchifolia, ageratum conyzoides and sonchus asper, to acquire a better understanding of the barriers each species imposes upon herbicide penetration, and provide information on how to overcome these obstacles. the completely expanded leaves from the third to the fifth nodes were collected from plants spontaneously occurring in the field. from the leaves of each species, three samples with approximately 1 cm2 were taken at the central portion and used for structure, and clarification studies and scanning-electron microscope (sem) observations. all species were found to be amphistomatic. the main leaf barriers against herbicide penetration in b. pilosa were found to be high trichome density and low stomatic density in the adaxial side. high content of epicuticular wax, high cuticle thickness in the adaxial side and low stomatic density on both sides were the herbicide barriers observed in the leaves of e. sonchifolia, while in a. conyzoides the barrier was low stomatic density in the adaxial side. s. asper's main leaf barriers were low stomatic density in the adaxial side and high epiderm thickness in the adaxial side.
Estudos anat?micos de folhas de espécies de plantas daninhas de grande ocorrência no Brasil. V - Leonurus sibiricus, Leonotis nepetaefolia, Plantago tomentosa e Sida glaziovii
Procópio, S.O.;Ferreira, E.A.;Silva, E.A.M.;Silva, A.A.;Rufino, R.J.N.;
Planta Daninha , 2003, DOI: 10.1590/S0100-83582003000300008
Abstract: the objective of this research was to study the leaf anatomy of the weed species leonurus sibiricus, leonotis nepetaefolia, plantago tomentosa and sida glaziovii to acquire a better understanding of the barriers each species imposes upon herbicide penetration, thus supporting the search for strategies to overcome these obstacles. completely expanded leaves from the third to the fifth nodes of the plants were collected in the field. three samples of approximately 1 cm2 were taken from the central portion of the leaves of each species to be used in the studies of structure and clarification as well as observations through a scanning-electron microscope (sem). l. sibiricus is the only hypostomatic species, while the others are amphistomatic species. the main leaf barriers observed against herbicide penetration in l. sibiricus were high trichomic density and stomata absence in the adaxial side; in l. nepetaefolia, the barriers were high trichomic density, high cuticle thickness in the adaxial side and low stomatic density in the adaxial side, whereas in p. tomentosa the barriers were high content of epicuticular wax, high trichomic density and high cuticle thicknesses. high trichomic density and low stomatic density in the adaxial side were the herbicide barriers observed in the leaves of s. glaziovii.
Estudos anat?micos de folhas de plantas daninhas: I - Nicandra physaloides, Solanum viarum, Solanum americanum e Raphanus raphanistrum
Ferreira, E.A.;Procópio, S.O.;Silva, E.A.M.;Silva, A.A.;Rufino, R.J.N.;
Planta Daninha , 2002, DOI: 10.1590/S0100-83582002000200001
Abstract: this research aimed to study the leaf anatomy of the weed species nicandra physaloides, solanum viarum, solanum americanum and raphanus raphanistrum to acquire a better understanding of the barriers each species imposes upon herbicide penetration. completely expanded leaves from the third to the fifth node were collected from plants spontaneously occurring in field. three samples, with approximately 1 cm2, were taken at the central portion of the leaves in each species. these samples were used in structural studies, clarification and observation using a scanning-electron microscope (sem). all species are amphistomatic. the main leaf barrier against herbicide penetration in n. physaloides was high trichomic density, whereas in s. viarum, the main barriers were low stomatic density in the adaxial side, high trichomic density, high content of epicuticular wax and high cuticle thickness. s. americanum's main leaf barriers were low stomatic density and high cuticle thickness in the adaxial side. high cuticle thickness in the adaxial side was the only barrier observed in leaves of r. raphanistrum.
Manejo de plantas daninhas na cultura da mandioca Weed management in cassava
D.V. Silva,J.B. Santos,E.A. Ferreira,A.A. Silva
Planta Daninha , 2012, DOI: 10.1590/s0100-83582012000400025
Abstract: A mandioca (Manihot esculenta) é cultivada em vários países, sendo de grande importancia como fonte de energia para alimenta o humana e animal e na gera o de empregos e renda. No Brasil, apesar de essa cultura apresentar alto potencial produtivo - em alguns estudos alcan ando valores superiores a 100 t ha-1 de raízes - , a produtividade nacional é baixa, atribuída em grande parte ao manejo inadequado das plantas daninhas. A interferência dessas plantas resulta em competi o pelos recursos essenciais, como nutrientes, água e luz. Além disso, o controle realizado de maneira incorreta das plantas daninhas nos mandiocais dificulta outros tratos culturais e aumenta os custos de produ o. Nesta revis o s o abordados os aspectos relativos ao manejo das plantas daninhas na cultura, descrevendo, de forma detalhada, os principais componentes de interferência. Discute-se, em várias situa es, o período crítico de competi o. Por fim, s o apresentados os principais métodos de controle visando à utiliza o do manejo integrado como forma sustentável do controle de plantas daninhas nessa cultura. Cassava (Manihot esculenta) is grown in many countries, being of great importance as an energy source for food, generating jobs and income. Although this crop has been proved to have high yield potential in some studies, reaching values above 100 t ha-1 roots, its national productivity in Brazil is low, being largely attributed to inadequate weed management. The interference of weeds results in competition for essential resources, such as nutrients, water, and light. In addition, incorrectly performed control of weeds in cassava can complicate management and increase production costs. In this review, aspects related to weed management in the culture are described, detailing the main components of interference. The critical period of competition, in many situations, is also discussed. Finally, the main methods of control aimed at the use of integrated management as a sustainable way of controlling weeds in this crop are presented.
Avalia??o fitossociológica da comunidade infestante em áreas de transi??o para o café organico
Ferreira, E.A;Fran?a, A.C;Carvalho,;Santos, J.B;D.V, Silva;Santos, E.A;
Planta Daninha , 2011, DOI: 10.1590/S0100-83582011000300010
Abstract: the objective of this study was to evaluate the effects of conventional and organic inputs on weed dynamics during the first and second years of agro-ecological transition. thus, an experiment was arranged in a six-year-old plantation, where transition to organic farming was initiated. the most important species in the first year of transition was ageratum conyzoides, in most areas evaluated. in the second year, there was a considerable change in the dominance relationship between the species, especially regarding leunurus sibiricus, which was the most important species in most areas studied during this period. there was also an increase in the number of species present in most areas in the second year. it was concluded that, during the two years of evaluation, changes were verified in the number, diversity, and importance relation between the species from one year to the other.
GELATIN DRYING PROCESS
Silva, E.A.;Neitzel, I.;Silva, L.H.M.;
Brazilian Journal of Chemical Engineering , 2001, DOI: 10.1590/S0104-66322001000400011
Abstract: in one of the stages of the gelatin production process, a highly concentrated solution of gel is cooled and extruded to form gelatin noodles, which are then laid on a drying belt. gelatin is a molecular colloid that is not porous under these drying conditions, and as a consequence, water migration occurs solely by diffusive processes. to achieve a commercial standard of dryness, the dependence of the diffusion coefficient as a function of temperature is used. this set of circumstances favors the appearance of sharp concentration gradients inside the gel. in a numerical simulation of the drying process these characteristics create difficult conditions for use of the traditional methods for solution of time-dependent partial differential equation models. this paper evaluates an implementation of the boundary element method to determine surface conditions of the gelatin particle.
GELATIN DRYING PROCESS
Silva E.A.,Neitzel I.,Silva L.H.M.
Brazilian Journal of Chemical Engineering , 2001,
Abstract: In one of the stages of the gelatin production process, a highly concentrated solution of gel is cooled and extruded to form gelatin noodles, which are then laid on a drying belt. Gelatin is a molecular colloid that is not porous under these drying conditions, and as a consequence, water migration occurs solely by diffusive processes. To achieve a commercial standard of dryness, the dependence of the diffusion coefficient as a function of temperature is used. This set of circumstances favors the appearance of sharp concentration gradients inside the gel. In a numerical simulation of the drying process these characteristics create difficult conditions for use of the traditional methods for solution of time-dependent partial differential equation models. This paper evaluates an implementation of the boundary element method to determine surface conditions of the gelatin particle.
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