Showing papers by "Universidade Federal de Santa Maria published in 2000"

Organic matter storage in a sandy clay loam Acrisol affected by tillage and cropping systems in southern Brazil.

Abstract: Soil organic matter decline and associated degradation of soil and environmental conditions under conventional tillage in tropical and subtropical regions underline the need to develop sustainable soil management systems. This study aimed first to evaluate the long-term effect (9 years) of two soil-tillage systems (conventional tillage: CT, and no-tillage: NT) and two cropping systems (oat (Avena strigosa Schreb)/maize (Zea mays L.): O/M; and oatacommon vetch (Vicia sativa L.)/ maizeacowpea (Vigna unguiculata (L.) Walp): OaV/MaC without N fertilization on total organic carbon (TOC) and total nitrogen (TN) concentrations in a sandy clay loam Acrisol in southern Brazil. The second objective was to assess soil potential for acting as an atmospheric CO2 sink. Under NT an increase of soil TOC and TN concentrations occurred, in both cropping systems, when compared with CT. However, this increase was restricted to soil surface layers and it was higher for OaV/MaC than for O/M. The OaV/MaC under NT, which probably results in the lowest soil organic matter losses (due to erosion and oxidation) and highest addition of crop residues, had 12 Mg ha ˇ1 more TOC and 0.9 Mg ha ˇ1 more TN in the 0‐30.0 cm depth soil layer, compared with O/M under CT which exhibits highest soil organic matter losses and lowest crop residue additions to the soil. These increments represent TOC and TN accumulation rates of 1.33 and 0.10 Mg ha ˇ1 per year, respectively. Compared with CT and O/M, this TOC increase under NT and OaV/MaC means a net carbon dioxide removal of about 44 Mg ha ˇ1 from the atmosphere in 9 years. NT can therefore be considered, as it is in temperate climates, an important management strategy for increasing soil organic matter. In the tropicals and subtropicals, where climatic conditions cause intense biological activity, in order to maintain or increase soil organic matter, improve soil quality and contribute to mitigation of CO2 emissions, NT should be associated with cropping systems resulting in high annual crop residue additions to soil surface. # 2000 Elsevier Science B.V. All rights reserved.

Biologia do jundiá Rhamdia quelen (Teleostei, Pimelodidae)

Abstract: O jundia, Rhamdia quelen, e encontrado desde o centro da Argentina ate o sul do Mexico, e seu cultivo esta aumentando no sul do Brasil. Portanto, o objetivo desta revisao e apresentar os dados existentes ate o momento sobre a biologia dessa especie. R. quelen pode atingir 50cm de comprimento e 3kg de peso, possui habito noturno e habita locais calmos e profundos dos rios. Os alevinos suportam agua do mar a 10%o, ate 9,0g/l de sal comum e pH na faixa de 4,0 a 8,5, com melhor crescimento das larvas na faixa de pH de 8,0 a 8,5. E uma especie euritermica. Esse peixe e omnivoro, com tendencia piscivora. A maturidade sexual e atingida no primeiro ano de vida. E uma especie ovulipara e, na natureza, os cardumes desovam em locais com agua limpa, calma e de fundo pedregoso. Nao apresenta cuidado parental. Possui dois picos reprodutivos por ano (um no verao e outro na primavera) e desova multipla. A inducao da desova apresentou bons resultados com gonadotrofina corionica humana (HCG) ou extrato hipofisario. O desenvolvimento embrionario de R. quelen e rapido e se da entre 3 a 5 dias. O melhor alimento artificial para larvas de R. quelen e baseado em lecitina de soja, figado bovino e levedura. Varias bacterias patogenicas e trematodeos digeneticos ja foram identificados em R. quelen. Para um melhor aproveitamento dessa especie na piscicultura, sao necessarios mais estudos relacionados ao efeito de parâmetros fisicoquimicos da agua, alimentacao artificial e crescimento em cativeiro.

C ? H-π Interactions in 1-n-Butyl-3-methylimidazolium Tetraphenylborate Molten Salt: Solid and Solution Structures

Abstract: The crystal structure of 1-n-butyl-3-methylimidazolium tetraphenylborate molten salt (1) shows C-H-pi interactions between the hydrogens of the imidazolium cation and the phenyl rings of the tetraphenylborate anion. The imidazolium ring is surrounded by three tetraphenylborate anions that are connected with the same cation by C-H-pi (phenyl rings) interactions. The nearest inter-ion interaction is found between the N-CH-N proton of the cation and the B-phenyl centroid (2.349 A) with a nearly T-shaped geometry. The inter-ionic solution structure of 1 has been investigated by the detection of inter-ionic contacts in 1H NOESY NMR spectra between the protons of the cation and the anion. The 1H-NMR spectra of molten salt 1 is almost independent of its concentration in [D6]DMSO solution, the imidazolium proton chemical shifts are in the expected region and there are no observable NOE effects between the protons of the cation with those of the anion, indicating that 1 behaves in [D6]DMSO as a solvent-separated ion pair. In CDCl3 the 1H-NMR spectra of 1 are concentration dependent and all the imidazolium protons are shielded as compared with those observed in [D6]DMSO. Moreover, the 1H NOESY NMR spectra show all the peaks affected by the interaction between the protons of the imidazolium cation and those of the anion, indicating that in CDCl3 1 possesses a contact ion pair structure. The NCHN proton of the cation exhibits the greatest shielding (up to -4.5 ppm). an indication of the existence of C-H-pi interactions, even in solution. The calculated distance of this proton to the phenyl centroid is 2.3 A for a C-H -pi angle of 180 degrees. The apparent volumes for the cation and anion, calculated from the measured 13C-NMR relaxation times, increase from 38 and 140 A3 in [D6]DMSO to 360 and 600 A3 in CDCl3, respectively; this indicates the formation of floating aggregates of the type (1)(n) in CDCl3 via weak hydrogen bonds, with increasing concentration.

Ab initio calculations for a hypothetical material: Silicon nanotubes

Abstract: Electronic and structural properties of a hypothetical material, silicon nanotubes, are examined through first-principles calculations based on density functional theory. Even considering that Si nanotubes have never been observed, this paper attempts to establish the theoretical similarities between Si and C, like band structures and density of states, as well as the main differences, especially associated with cohesive energies. The band-structure calculations for silicon nanotubes show that, similar to carbon structures, depending on their chiralities, they may present metallic (armchair) or semiconductor (zigzag and mixed) behaviors.

Eficiência de armadilhas de queda (pitfall traps) em amostragens de anfíbios e répteis no Brasil

Abstract: The effectiveness of pitfall traps associated with drift fences to capture amphibians and reptiles in three field studies, in Rio Grande do Sul (extreme southern Brazil), Sao Paulo (Sao Paulo, southeastern Brazil), and Amazonas (Amazonas, northern Brazil) is described. At Santa Maria, a total of 2040 amphibians and reptiles were caught in 30 pitfalls (200 L, with drift fence) during 18 months of study (capture efficiencies of 3.78 amphibians and reptiles/pitfall/month and 0.14 snake/pitfall/month). At Itirapina, Sao Paulo, 1262 amphibians and reptiles were obtained in 72 pitfalls (100 L, with drift fence) during six months (capture efficiencies of 11,9 amphibians and reptiles/pitfall/month and 0,38 snake/pitfall/month). At Rio Pitinga, Amazonas, over 600 amphibians and reptiles were caught in 50 pitfalls (100-150 L, with drift fence) during three months (capture efficiencies of ca. 4.00 amphibians and reptiles/pitfall/month and 0.87 snake/pitfall/month). Capture efficiencies of 1.25 to ~3.92 amphibians and reptiles/pitfall/month were obtained in four other unpublished studies made by other authors in Brazil, all of them using 20-35 L traps, either with or without drift fences. Higher capture efficiencies for snakes were obtained in those studies in which larger containers (100-200 L) were used. The results presented here indicate that pitfall traps are extremely useful to sample amphibians and reptiles in Brazil, especially anurans and lizards. From these results, it is possible to preview the capture of 125 to 1200 amphibians and reptiles with 100 pitfalls during one month, regardless of the size of the pitfalls and sampling design of the trap arrays. The main advantages and disadvantages of the method and detailed guidelines on how to design, install, and use the traps is discussed.

Possible primary ecological niche of Cryptococcus neoformans.

Abstract: To study hollows of living trees as natural habitats of Cryptococcus neoformans in an endemic area of cryptococcosis in the northeastern region of Brazil, samples of decaying wood were collected inside 32 hollows of living trees and plated on niger seed agar. Identification of C. neoformans was based upon morphological and physiological tests. Canavanine-glycine-bromothymol medium was used to screen the varieties and Crypto Check Iatron Kit to serotype the isolates. A total of 123 C. neoformans colonies were recovered from samples of six (18.5%) out of 32 hollow trees. C. neoformans var. neoformans and C. neoformans var. gattii were found occurring alone (pink shower tree, fig tree and pottery tree) or sharing the same hollow (pink shower tree). Long lasting positivity (19-36 months) and significant number of cfu of C. neoformans per gram of decaying wood (0.15-21.7 x 10(3) cfu g(-1)) inside hollows of pink shower tree, fig tree and pottery tree were observed, indicating colonization of these habitats by the fungus. For the first time, C. n. var. neoformans and C. n. var. gattii were found sharing the same natural biotope, thus establishing a possible link between them in their life cycle in nature and suggesting the primary natural niche for the species.

Diphenyl diselenide and diphenyl ditelluride differentially affect δ‐aminolevulinate dehydratase from liver, kidney, and brain of mice

Abstract: In the present study, the inhibitory effect of diphenyl diselenide and diphenyl ditelluride after in vitro, acute (a single dose), or chronic exposure (14 doses) was examined in mice 24 hours after the last administration. In vitro, diphenyl diselenide, and diphenyl ditelluride inhibited δ-aminolevulinate dehydratase (δ-ALA-D) from brain, liver, and kidney with a similar potency (IC50 5–10 μM), and at 120 μM, they increased the rate of dithiothreitol (DTT) and reduced glutathione (GSH) oxidation. After a single dose (sc), diphenyl diselenide (1 mmol/kg) inhibited the liver (22%, p < 0.01) and brain (27%, p < 0.01) δ-ALA-D, but it did not inhibit the kidney enzyme. After a single dose (sc), diphenyl ditelluride (0.5 mmol/kg) inhibited liver (46%, p < 0.01), kidney (21%, p < 0.05), and brain (39%, p < 0.01) δ-ALA-D. Chronic exposure to diphenyl diselenide (0.125 and 0.250 mmol/kg) caused significant (p < 0.05) increase in liver and liver-to-body weight ratio and inhibited liver (40 and 60%, respectively) and brain (21 and 40%, respectively) δ-ALA-D. Kidney δ-ALA-D was not inhibited significantly after exposure to diphenyl diselenide. Total nonprotein −SH concentration was decreased only in liver of animals exposed for 14 days to selenide. Chronic exposure to diphenyl ditelluride (0.010 and 0.025 mmol/kg) caused significant (p < 0.05) inhibition of liver (28 and 42%, respectively) and brain (23 and 54%, respectively) δ-ALA-D. Kidney δ-ALA-D was not inhibited significantly by diphenyl ditelluride. Total nonprotein −SH concentration was decreased to a different extent after acute or chronic treatment with diphenyl ditelluride depending on analyzed tissue. Hemoglobin content was decreased significantly by 17 and 22% after chronic treatment with 0.125 and 0.25 mmol/kg diphenyl diselenide, respectively. Chronic exposure to 0.010 mmol/kg diphenyl ditelluride caused a reduction of 17% in hemoglobin content that tended to be significant (p < 0.10). These results suggest that δ-ALA-D inhibition after exposure to organochalcogens may perturb heme-dependent metabolic pathway and contribute to the toxicological properties of these compounds. © 2000 John Wiley & Sons, Inc. J Biochem Mol Toxicol 14:310–319, 2000

Effect of no-till cropping systems on soil organic matter in a sandy clay loam Acrisol from Southern Brazil monitored by electron spin resonance and nuclear magnetic resonance

Abstract: In weathered tropical and subtropical soils organic matter is crucial for soil productivity and its quantity depends heavily on soil management systems. This study evaluated the effect of no-till cropping systems on organic matter content and quality in a sandy clay loam Acrisol soil (Paleudult in US taxonomy) from Southern Brazil. Ten cropping systems with varying additions of C and N were conducted for 12 years (from 1983 to 1994). The addition of crop residues increased total organic carbon (TOC) and total nitrogen (TN) in the soil at 0‐17.5 cm depth, and this increase was directly related with C and N added or recycled by the systems. The crop residues added to the soil were associated with reduced semiquinone free radical concentration, detected by electron spin resonance (ESR), in the organo-mineral aggregates <53 mm and humic acid (HA) samples, in the soil at 0‐2.5 cm depth. This showed that stable organic matter originating from crop residues was less humidified than the original soil organic matter. Results obtained from organo-mineral aggregates showed a higher amplitude (highest and lowest values were 5.47 and 2.09 10 17 spins g ˇ1 of TOC, respectively) of semiquinone free radical concentration than HA samples (highest and lowest values were 2.68 and 1.77 10 17 spins g ˇ1 of HA, respectively). These data showed that alterations due to tillage in soil organic matter characteristics, e.g., humification degree can be better identified through a combination of soil physical fractionation and spectroscopic analysis. Semiquinone content in the HA samples, detected by ESR, related significantly to aromaticity, as measured by nuclear magnetic resonance (NMR) of 13 C. Management systems including no-till and cropping systems with high C and N additions to the soil improved its quality in Southern Brazil. # 2000 Elsevier Science B.V. All rights reserved.

New Benzodiazepines Alter Acetylcholinesterase and ATPDase Activities

Abstract: This study examines the effect of new 1,5 benzodiazepines on acetylcholinesterase (AChE) and ATPDase (apyrase) activities from cerebral cortex of adult rats Simultaneously, the effects of the classical 1,4-benzodiazepine on these enzymes were also studied for comparative purpose The compounds 2-trichloromethyl-4-phenyl-3H-1,5-benzodiazepin and 2-trichloromethyl-4-(p-methyl-phenyl)-3H-1,5-benzodiazepin significantly inhibited acetylcholinesterase activity (p < 001) when tested in the range of 018–035 mM The inhibition caused by these two new benzodiazepines was noncompetitive in nature Similarly, at concentrations ranging from 0063 to 025 mM, the 1,5 benzodiazepines inhibited ATP and ADP hydrolysis by synaptosomes from cerebral cortex (p < 001) However, the inhibition of nucleotide hydrolysis was uncompetitive in nature Our results suggest that, although diazepam and the new benzodiazepines have chemical differences, they both presented an inhibitory effect on acetylcholinesterase and ATPDase activities

Densidade do solo, atributos químicos e sistema radicular do milho afetados pelo pastejo e manejo do solo

Abstract: A integracao lavoura-pecuaria e uma alternativa de renda dos produtores no sul do Brasil. Entretanto, o pisoteio animal e, ou, o preparo de solo podem compacta-lo, prejudicando o crescimento radicular e a produtividade das plantas. Estudaram-se os efeitos do pisoteio animal em regime de pastejo continuo durante o inverno/primavera e do impacto do plantio direto e do preparo convencional de solo no estado de compactacao, atributos quimicos e distribuicao radicular. Em Podzolico Vermelho-Amarelo de textura superficial franca, foi implantada uma pastagem de estacao fria composta por aveia (Avena strigosa Schreb) e azevem (Lolium multiflorum L.). A carga animal variou conforme o crescimento da pastagem. Em dezembro de 1996, foi implantada a cultura do milho (Zea mays L.) para a producao de silagem, usando os seguintes tratamentos: plantio direto na area nao pastejada, plantio direto apos o pastejo, preparo convencional de solo na area nao pastejada e preparo convencional de solo apos pastejo. As avaliacoes apresentadas neste estudo sao referentes ao terceiro ano de cultivo, no qual houve um periodo de pastejo de 107 dias. Aos 45 dias da emergencia do milho, foram abertas trincheiras (100 x 40 cm) para visualizar a distribuicao do sistema radicular e coletar amostras de solo, a cada 5 cm, para caracterizacao quimica e determinacao da densidade do solo e de raizes. Ao longo do perfil (0-40 cm), o desenho da distribuicao de raizes indicou maior quantidade de raizes no preparo convencional de solo, concordando com os resultados de densidade de raizes. O pisoteio animal nao teve efeito sobre as caracteristicas fisicas, possivelmente pelo fato de o residuo da pastagem permanecer proximo a 1,0 Mg ha-1 de materia seca. A densidade do solo no plantio direto, na camada de 5-10 cm, foi de 1,41 Mg m-3, tanto na area pastejada como na nao pastejada. No preparo convencional de solo, esses valores foram de 1,15 Mg m-3, na area pastejada e de 1,12 Mg m-3, na area nao pastejada. A produtividade de graos de milho (4,55 Mg ha-1) e de silagem (34,66 Mg ha-1) nao foi afetada pelo pastejo ou pelo preparo do solo. O sistema de manejo do solo teve maior influencia na densidade do solo do que o pisoteio animal, considerando o controle da carga animal ajustado ao crescimento da pastagem.

Suscetibilidade à compactação de um latossolo vermelho-escuro e de um podzólico vermelho-amarelo

Abstract: Soil compaction of the agricultural soils is a result of soil machine interactions, which influence physical and biological soil properties and their relations with crop growth and yield. The objective of this study was to determine the compression index, the preconsolidation pressure and the soil strain of a Haplortox (LE) and a Paleudalf (PV), with different initial state of compaction and water saturation. Undisturbed soil samples were collected in two soils and at two depths, at no tillage and conventional tillage, at several locations and different times to obtain a natural variation of bulk density, corresponding to different initial levels of compactness and water saturation. For the uniaxial compression test, successive static loads of 12.2; 25; 50; 100; 200; 400 and 800 kPa were used, during five minutes for each load. This was determined at previous tests, where 99% of the soil strain had occurred at the time. Soil strain showed differentiated behaviors for each soil. For soil Haplortox, under low water saturation ( 60%) water saturation, whereas for the intermediate saturation (30 to 60%) the model was linear. The compression index correlated negatively with the initial bulk density and with water saturation in PV. For high initial bulk density (> 1.45 Mg m-3), the Haplortox had greater susceptibility to compaction when water saturation was near 70%, whereas when the same soil had low compaction (bulk density < 1.30 Mg m-3), the major susceptibility occurred under lower water saturation (near 50%). Multiple regression equations for preconsolidation pressure, using initial bulk density and water saturation, had low determination coefficient (0.28 for PV and 0.32 for LE), although significant, which indicates the need for incorporation of more variables in these models.

Doenças do sistema nervoso central em bovinos no Sul do Brasil

Abstract: A retrospective study was carried out on 6,021 necropsies of cattle performed over a 36-year period in southern Brazil. Of those, 552 (9.16%) presented neurological clinical signs and their necropsy protocols were reviewed to gather information on type of gross and histopathological diagnosis, etiology, and clinical signs. In 147 cases (26.63% of 552) there were no significant lesions in the central nervous system, in 79 (14.31% of 552) no samples of nervous tissue were submitted to the laboratory and in 21 (3.81% of 552) the tissues submitted were autolysed and not suitable for histological diagnosis. Lesions found in the remaining 305 cases were classified as inflammatory, degenerative, circulatory, congenital, and neoplastic. The inflammatory lesions accounted for the largest category (66.89% of 305 cases). This was further divided in lesions caused by viruses (57.38% of 305 cases) and by bacteria (9.51% of 305 cases). Diseases caused by viruses were rabies (49.51% of 305 cases), necrotizing meningo-encephalitis by bovine herpesvirus (4.59% of 305 cases), and malignant catarrhal fever (3.28% of 305 cases). The degenerative changes were represented by 74 cases (24.26% of 305 cases) and included status spongiosus due to liver failure induced by Senecio spp poisoning (10.49% of 305 cases) or to the direct effect of poisoning by Ateleia glazioviana (0.33% of 305 cases); cases of liver failure not associated with morphological changes in the brain (2.95% of 305 cases), myelomalacia due to cord compression (2.62% of 305 cases), primary neuronal degeneration associated with Solanum fastigiatum poisoning (2.29% of 305 cases); polioencephalomalacia (1.97% of 305 cases); tetanus (1.31% of 305 cases) and intestinal coccidiosis in calves, ketosis, and botulism with one case each (0.33% of 305 cases). Circulatory disturbances accounted for 19 cases (6.23% of 305 cases) and included cerebral babesiosis (5.57% of 305 cases) and hemorrhages due to trauma (0.66% of 305 cases). Congenital conditions represented 2.29% of the 305 cases and included cerebelar abiotrophy (two cases) and one case each of porencephaly, hypomyelinogenesis, demyelination, hydrocephalus, and cerebellar malformation. Only one neuroectodermal neoplasm (0.33% of 305 cases) was found in this series.

Leguminosas e adubação mineral como fontes de nitrogênio para o milho em sistemas de preparo do solo

Abstract: O nitrogenio e um nutriente requerido em grande quantidade pelo milho. O solo tem limitada capacidade de atender a esta demanda, sendo por isto utilizadas outras fontes de N como leguminosas e adubacao mineral. A combinacao destas duas fontes de N pode contribuir para a sustentabilidade do agroecossistema. Com o objetivo de avaliar a disponibilidade de N em sistemas de preparo do solo e cultura, foi realizada esta pesquisa, utilizando um experimento de longa duracao na UFRGS (RS) em um Argissolo Vermelho-Escuro distrofico. Os tratamentos utilizados foram tres sistemas de preparo: convencional, reduzido e direto; tres sistemas de cultura: aveia/milho, aveia + ervilhaca/milho + caupi e ervilhaca/milho, e tres doses de N: 0, 90 e 180 kg ha-1 aplicadas em cobertura no milho. A associacao do sistema plantio direto com o uso de leguminosas foi eficiente em promover o aumento do estoque de N total no solo. Embora tenha sido constatada maior velocidade de decomposicao de residuos no preparo convencional do que no plantio direto, ambos os sistemas apresentaram potencial de sincronismo da liberacao de N dos residuos com a demanda do milho. Esta cultura no sistema plantio direto apresentou menor producao de materia seca e absorcao de N do que no preparo convencional, porem nao houve diferenca no rendimento entre estes sistemas de preparo. A equivalencia em fertilizante nitrogenado foi estimada em 55 e 38 kg ha-1, respectivamente, para a ervilhaca e aveia + ervilhaca.

Efeito do volume de tubetes e tipo de substratos na qualidade de mudas de Cryptomeria japonica (L.F.) D. Don.

Abstract: Cryptomeria japonica (L F) D Don is a species of great potential for planting in elevated and cold regions of Brazil It is remarkable for its fast growth, good adaptation to the climate and soil of Southern Brazil, and it also shows a good response to silvicultural technologies In addition, it is notable for the quality and diversity of its raw material usage for the industries of pulp and paper, plywood, construction of houses, furniture, boats, ships, etc The experimental plan was bifactorial in the entirely randomized design with 8 treatments, 5 repetitions with 40 seedlings per treatment The results indicated that for the production of seedlings of this species, the substrate soil + vermiculite showed the best development of the seedlings in 120 cm 3 containers

Pajé, an interactive visualization tool for tuning multi-threaded parallel applications

Abstract: This paper describes Paje, an interactive visualization tool for displaying the execution of parallel applications where a potentially large number of communicating threads of various life-times execute on each node of a distributed memory parallel system. Paje is capable of representing a wide variety of interactions between threads. The main characteristics of Paje, interactivity and scalability, are exemplified by the performance tuning of a molecular dynamics application. In order to be easily extensible, the architecture of the system was based on components which are connected in a data flow graph to produce a given visualization tool. Innovative components were designed, in addition to “classical” components existing in similar visualization systems, to support scalability and interactivity.

Alterações de atributos do solo pela calagem superficial e incorporada a partir de pastagem natural

Abstract: A aplicacao superficial de calcario pode ser uma alternativa para a correcao da acidez do solo sob plantio direto. Este trabalho avaliou as modificacoes em alguns atributos quimicos provocadas pela aplicacao de calcario superficial e incorporado ao solo a partir de pastagem natural. O experimento foi feito na area Experimental do Departamento de Solos da Universidade Federal de Santa Maria (RS), num Argissolo Acinzentado distrofico plintico. Os tratamentos, com 0,0, 2,0, 8,5 e 17,0 t ha-1 de calcario incorporado na camada de 0-20 cm e em superficie, foram distribuidos em blocos ao acaso, com quatro repeticoes. Aos 24 meses, reaplicou-se em superficie a dose no tratamento de 2,0 t ha-1. Aos 6, 18, 36 e 48 meses da aplicacao do calcario, coletaram-se amostras de solo nas profundidades de 0,0-2,5; 2,5-5,0; 5,0-10,0 e 10,0-15,0 cm. Avaliaram-se os atributos quimicos relacionados com a acidez do solo. A correcao da acidez do solo foi proporcional a dose de calcario aplicada, independentemente do modo de aplicacao. A aplicacao de calcario superficial criou uma frente de correcao da acidez em profundidade proporcional a dose e ao tempo. Foram necessarios 36 meses para que a saturacao com aluminio atingisse nivel proximo de zero na camada de 0,0-2,5 cm com a aplicacao de 2,0 + 2,0 t ha-1; 36 meses para a camada 2,5-5,0 cm com 8,5 t ha-1; e 48 meses para a camada 5,0-10,0 cm com 17,0 t ha-1.

Avaliação do conhecimento popular e práticas cotidianas em saúde bucal

Abstract: OBJETIVO: Avaliar o conhecimento popular e as praticas cotidianas em saude bucal de usuarios de servicos publicos de saude. METODOS: A populacao estudada foi selecionada a partir de uma amostra estratificada de usuarios que procuraram atendimento nas unidades sanitarias da zona urbana de Santa Maria, RS. Os dados foram coletados por meio de entrevista semi-estruturada e organizados em conjuntos de categorias descritivas, permitindo sua distribuicao em tabela de frequencia. RESULTADOS: Verificou-se que predominam usuarios entre 21 e 40 anos de idade, do sexo feminino e com padrao socioeconomico baixo. A busca pela saude e o controle das doencas bucais sao atribuidos a responsabilidade individual de realizar a higiene bucal e procurar tratamento dentario. A presenca e os beneficios do fluor no creme dental e na agua de beber nao foram reconhecidos pela populacao estudada. CONCLUSOES: Os programas de saude devem considerar os aspectos relativos ao conhecimento e as praticas em saude bucal, para viabilizar o processo de capacitacao da populacao e promover a responsabilizacao coletiva da promocao da saude em todos os niveis da sociedade.

Micotoxinas e Micotoxicoses na Avicultura

Abstract: Esta revisao tem como objetivo principal mostrar, baseado em dezenas de pesquisas realizadas, os efeitos toxicos das micotoxinas aflatoxinas, tricotecenos, zealenona e fumonisinas sobre o desempenho das aves. O descobrimento das propriedades hepatotoxicas e hepatocarcinogenicas de algumas linhagens de Aspergillus flavus e A. parasiticus em perus, na Inglaterra, no inicio da decada de 1960, seguida pela elucidacao da estrutura de seus metabolitos toxicos, as aflatoxinas, deu novo enfoque e prioridade para a pesquisa sobre micotoxinas. Analises de aflatoxinas realizadas no Laboratorio de Analises Micotoxicologicas (LAMIC) da Universidade Fedaral de Santa Maria, entre os anos de 1986 e janeiro de 2000, em 15.600 amostras de alimentos destinados principalmente ao consumo animal, demonstram que no milho analisado, 41,9% das amostras estavam contaminadas por aflatoxinas. Em surtos de aflatoxicose no campo, uma das caracteristicas mais marcantes e a ma absorcao que se manifesta como particulas de racao mal digeridas na excreta das aves. Tambem observa-se, em frangos e poedeiras que recebem AFL, extrema palidez das mucosas e pernas. Dietas deficientes em riboflavina ou colecalciferol (vit. D) tornaram frangos sensiveis, nos indices de desenvolvimento corporal, a concentracoes muito baixas de AFL. O efeito aflatoxina nos frangos e maior na fase inicial de crescimento, ou seja, quando as aves ingeriram aflatoxina nos primeiros 21 dias de vida, e quanto maior o nivel de stress do lote, menor a quantidade de AFL para afetar negativamente seu desempenho, seja na producao de carne ou de ovos. As principais micotoxinas do grupo dos tricotecenos sao: toxina T-2; deoxynivalenol (DON); diacetoxyscirpenol (DAS), todas produzidas atraves de diversas especies de fungos do genero Fusarium. Alem dos tricotecenos, o fusarium tambem pode produzir zearalenona e fumonisinas. Dessas fusarium-toxinas, somente toxina T-2 gera patologias serias nas aves, como lesoes orais e imunodepressao. As fumonisinas afetam o desempenho de frangos de corte a partir de uma ingestao de 75 ppm. Ja zearalenona e DON sao inocuas quando ingeridas por aves. Para o controle de contaminacao de micotoxinas nos alimentos, o melhor metodo e prevenir o crescimento de fungos, apertando-se no controle de qualidade da materia prima. Metodos alternativos podem ser usados, utilizando-se antifungicos ou adsorventes na racao. O monitoramento dos graos recebidos ou a receber e o ponto fundamental num programa de controle de micotoxinas. Isso deve ser feito atraves de um programa amostral consistente da massa de graos recebida ou a ser adquirida, com analises periodicas das micotoxinas.

Resistência mecânica do solo à penetração influenciada pelo tráfego de uma colhedora em dois sistemas de manejo do solo soil strength as affected by combine wheel traffic and two soil tillage systems

Abstract: Engenheiro Agronomo, PhD., Professor Titular do Departamento de Solos, Centro de Ciencias Rurais, UFSM. Bolsista do CNPq.RESUMOA resistencia mecânica do solo a penetracao podelimitar o crescimento do sistema radicular e a produtividade dasplantas. O estudo objetivou avaliar a resistencia mecânica dosolo a penetracao nas zonas de trafego e entre trafego de umacolhedora de graos, em dois sistemas de manejo do solo e duascondicoes de umidade do solo. Os tratamentos foram: plantiodireto, nao trafegado pelas rodas da colhedora e no rastro dopneu dianteiro da colhedora; na area com preparo do solo, naotrafegado pelas rodas da colhedora e no rastro do pneu dianteiroda colhedora. Determinaram-se a resistencia mecânica do solo apenetracao com um penetrografo, realizando leituras eletronicasde resistencia a cada 0,15cm de profundidade, e a umidade dosolo, ate uma profundidade de 40cm, em duas condicoes deumidade do solo (seco e umido), num Latossolo Vermelho-Escuro, argiloso. Nesses mesmos locais, foram coletadas amos-tras para determinacao da umidade do solo. O peso distribuidono eixo dianteiro da colhedora foi de 5,0Mg, sendo a area decontato com o solo igual a 0,283m

Cinomose: achados epidemiológicos de 250 casos

Abstract: A review of the number of dogs submitted for necropsy at the Department of Veterinary Pathology of the Federal University of Santa Maria, RS, between 1985-1997 has shown that 11.7% (250/2136) had lesions and inclusion bodies characteristic of infection by canine distemper virus (CDV). Most of these cases occurred during the winter months in dogs that were less than 1.5 year old, which were submitted by residents from the city of Santa Maria. Canine distemper is considered endemic in this city. Significant differences in susceptibility were not observed between males and females. Mongrel dogs were super-represented, but dolichocephalic breeds were more affected than brachycephalic ones. Distemper encephalopathy with typical CDV inclusion bodies, especially in astrocytes, was the main lesion and occurred in 82% of these cases. Eosinophilic inclusion bodies characteristic of canine distemper were also observed in epithelial cells of the urinary bladder (15%), lung (6%), stomach (3%), kidney (1%), and tonsil (0.5%).

Intrahippocampal spermidine administration improves inhibitory avoidance performance in rats.

Abstract: Polyamines are polycations present at high concentrations in the mammalian brain. We investigated the effect of an intrahippocampal infusion of spermidine, a polyamine agonist, immediately post-training on the inhibitory avoidance learning paradigm in rats. Bilateral intrahippocampal microinjection of spermidine (0.02-20 nmol) caused an increase in test step-down latencies at low concentrations. Administration of arcaine (0.002-0.2 nmol), an antagonist of the N-methyl-D-aspartate (NMDA) receptor polyamine binding site, did not modify the test step-down latencies. In contrast, co-administration of arcaine and spermidine completely reversed the facilitatory effect of spermidine on the test step-down latencies. These results provide evidence that polyamines may be involved in learning and memory modulation.

Cria e terminação de cordeiros confinados

Abstract: The experiment was carried out with the objective to evaluate the weight gain, dry matter intake and food conversion of feedlot lambs and slaughtered at 28 or 33kg and of their mothers until weaning. Twenty-two intact male lambs, sired by Texel males, from crossbreed Texel -Ideal dams were used. The lambs were confined in individual stall together, with their respective mothers until weaning (45 days of age). During this period, each pair was fed to fit the mothers' nutricional requirements. The diet contained 70% of roughage and 30% of concentrate. From weaning on, the diet was formulate to provide the nutricional requirements of the lambs, and contained 60% of roughage and 40% of concentrate. The values obtained for weight gain, dry matter intake (kg/animal/day; % live weight and g/metabolic size) and food conversion of lambs, did not differ (P>0.05) among the weights of slaughter, the means obtained were 0.245kg, 0.712kg; 2.99%; 66.02g e 4.32, respectively.

Manejo do nitrogênio no milho em sucessão a plantas de cobertura de solo, sob plantio direto

Abstract: Estabelecida a hipotese de que a antecipacao da adubacao nitrogenada promove acrescimo no rendimento de graos de milho pela maior disponibilidade de N nos estadios iniciais de desenvolvimento, foi realizado um trabalho com o objetivo de avaliar diferentes manejos de N para o milho cultivado em sucessao a plantas de cobertura de solo. O experimento foi desenvolvido em area do Departamento de Solos da Universidade Federal de Santa Maria (RS), nos anos agricolas de 1996/97, 1997/98 e 1998/99, em Argissolo Vermelho distrofico arenico (Hapludalf). O delineamento experimental foi de blocos ao acaso com parcelas subdivididas e tres repeticoes. Nas parcelas principais (25 x 5 m), foram cultivadas tres especies para cobertura de solo no inverno: aveia preta (Avena strigosa Schieb), aveia preta + ervilhaca (Vicia sativa L.) e nabo forrageiro (Raphanus sativus). Nas subparcelas (5 x 5 m), aplicou-se N para o milho da seguinte maneira: (a) 00-00-00, (b) 00-30-90, (c) 30-30-60, (d) 60-30-30 e (e) 90-30-00, cuja sequencia para cada tratamento corresponde a quantidade de N em kg ha-1 aplicado em pre-semeadura-semeadura-cobertura do milho. A aplicacao de N em pre-semeadura foi realizada apos o manejo das plantas de cobertura de solo no inverno, enquanto em cobertura o N foi aplicado quando as plantas de milho estavam com quatro a seis folhas desenroladas. Utilizou-se ureia como fonte de N. Segundo os resultados, o milho cultivado em sucessao ao consorcio com aveia preta + ervilhaca mostrou melhor desempenho do que quando cultivado sobre residuos de aveia preta e nabo forrageiro. A aplicacao de N em pre-semeadura do milho e uma atitude de risco, sendo mais segura a aplicacao de N na semeadura e em cobertura.

Aspectos fitossociológicos de fragmento de floresta estacional decidual, santa maria, rs

Abstract: This work aimed at studying the vegetation in a fragment of Deciduous Seasonal Forest under successional process, in an area of the Tabor Association (29 0 43’ S; 53 0 47’ W), municipal district of Santa Maria, RS, Brazil. Sixteen sample units (10x20m) were systematically located in the area to allow the recording (measurement and indentification) of individual plants with a Circumference at Breast Height equal to or larger than 30cm. Sampling was also carried out in circular units with radii of 1,78m to count up and identify the regeneration (individual with CBH smaller than 30 cm). The occurrence of 64 species of trees and shrubs comprising 54 genera and 31 botanical families was observed. The most important species were Myrocarpus frondosus, Cupania vernalis , Ocotea puberula , Patagonula americana , Casearia sylvestris , Luehea divaricata , Enterolobium contortisiliquum and Helietta apiculata . In the regeneration the species with higher density of individuals were Trichilia elegans , Nectandra megapotamica , Actinostemon concolor , Piper gaudichaudianum , Cupania vernalis, Hybanthus bigibbosus, Aiouea saligna and Parapiptadenia rigida . It was demonstrated the evidence of a continuous successional process, through the replacement of species in the several strata of the forest, with some well represented from the regeneration up to the higher forest stratum.

Microscopic picture of the single vacancy in germanium

Abstract: A complete microscopic picture of the germanium vacancy is presented, and our results are compared with recent measurements. We analyze, through first principles calculations, the structural relaxations, Jahn-Teller distortions, and orbitals for the charge states $(++,+,0,\ensuremath{-},\ensuremath{-}\ensuremath{-}).$ The formation energies for the different charge states are presented, as well as the positions of the $(++/+),$ $(+/0),$ $(0/\ensuremath{-}),$ and $(\ensuremath{-}/\ensuremath{-}\ensuremath{-})$ levels, and we obtain that the vacancy in Ge is not an Anderson negative-$U$ system, as opposed to the silicon vacancy. We propose as an explanation a much smaller electron-lattice coupling for the E mode in germanium than in silicon.