Showing papers by "Federal University of São Carlos published in 1987"

Isothermal and adiabatic nucleation in glass

Abstract: A summary of both classical (isothermal) and adiabatic theories of nucleation is presented. Using experimentally determined parameters, such as viscosity, specific heat, glass transition temperature (Tg), melting temperature (Tf) and heat of fusion, the temperatures of maximum crystal nucleation rates, Tmax, were calculated for several glass forming systems and compared with experimental data. It is shown that both theories give a good estimate for Tmax. For systems which do not show volume (homogeneous) nucleation, Tmax is lower than Tg. For systems which show volume nucleation, Tmax >Tg. It is concluded that both theories can be used to predict the occurrence of internal crystal nucleation in glasses and that, in general, a high value of Tg (Tg/Tf > 0.58) indicates the absence of internal nucleation.

Adaptative features of enzymes from family sciaenidae (perciformes)—I. studies on soluble malate dehydrogenase (s-MDH) and creatine kinase (CK) of fishes from the south coast of uruguay

Abstract: 1. 1. Electrophoretic analysis of the soluble malate dehydrogenase ( s -MDH) and creatine kinase (CK) isozyme patterns of three species of temperate fishes (Sciaenidae, Perciformes) indicates at least two loci for s -MDH, Mdh-A and Mdh-B, and four CK, Ck-A, Ck-B, Ck-C and Ck-D. 2. 2. The subunits encoded by these loci occurred at different levels in different tissues and organs analyzed. 3. 3. Through electrophoretic analysis the products of these loci showed different behaviour to changes in temperature. 4. 4. Relative activities of s -MDH and CK isozymes were compared by Klebe's (1975) method to determine pattern of divergence of duplicated gene expression in the three studied species.

Simultaneous Determination of Oxalate and Carbonate

Abstract: A procedure for simultaneous measurements of carbonate and oxalate contents in nonaqueous samples is presented. It is based on determination of the lead ion concentration by d.c. polarography. The determination of oxalate and carbonate is possible in the range of 0.1 mM up to 10 mM.

Biochemical and physiological properties of the lactate dehydrogenase allozymes of the Brazilian teleost, Leporinus friderici, Anostomidae, Cypriniformes

Abstract: 1. 1. Lactate dehydrogenase polymorphism of Leporinus friderici is determined by two loci, each one encoded by two alleles—Ldh-A, Ldh-A′ and Ldh-B and Ldh-B′. 2. 2. Biochemical characterization of the different LDH phenotypes was carried out. Substrate saturation curves show that extracts, where the LDH-B predominates, are much more sensitive to substrate inhibition and have higher thermostability than skeletal muscle extracts where the LDH-A predominates. 3. 3. Pyruvate affinity parameters of the different LDH-B phenotypes show differential values in all temperatures assayed. LDH-BB phenotypes presented always greater affinity values than the LDH-BB′ and B′B′ ones. 4. 4. The different LDH-B phenotypes show differential thermostability when tested at 65°C, so, the LDH-B′B′ phenotype had higher stability than the LDH-BB′ and LDH-BB phenotypes. This was corroborated with the isozymes partially purified. 5. 5. A variation was detected in the LDH-B phenotype frequencies since the experiment was started in 1980. 6. 6. All these features suggest that this polymorphism may have an adaptive significance in relation to environmental variability, i.e. temperature fluctuations and water pollution due to industrial waste that notably increased in these last years.

Adaptative features of enzymes from family sciaenidae--II. Studies on phosphoglucose isomerase (PGI) of fishes from the south coast of Uruguay.

Abstract: 1. 1. The electrokinetic and thermostability properties of phosphoglucose isomerase (PGI) in three species of temperate fishes (Perciformes, Acanthopterygii)—Cynoscion striatus, Macrodon ancylodon and Micropogonias furnieri—have been analyzed in order to study the adaptative nature of protein heterogeneity found in ectotherms. 2. 2. Unlike most diploid fishes the PGI of these species seemed to be encoded by three PGI loci. 3. 3. The subunits encoded by these loci occured at different levels in the different tissues and organs analyzed. 4. 4. Genetic variants at two loci (Pgi-A and Pgi-B2) were detected in Cynoscion striatus, and at one (Pgi-A) in Micropogonias furnieri. 5. 5. The product of these loci could be separated in three PGI regions based on their electrophoretic distribution and thermostability properties. 6. 6. The more anodal region (including isozymes and allozymes) was more thermolabile than the less anodal one, which is predominant in a single tissue skeletal muscle. 7. 7. Relative activities of PGI isozymes were compared by Klebe's method to determine pattern of divergence of duplicated gene expression in the three species studied.

The role of thermal contraction stresses associated to inclusions in the formation of the final microstructure of weld metal deposits

Abstract: The effect of deoxidation products on the formation of the final microstructure of weld deposits has been studied on a ferritic-austenitic stainless steel. Results show that the product phase austenite nucleates on dislocations set up by thermal contraction stresses. The presence of these defects has been ascertained by transmission electron microscopy and calculation confirms the existence of a plastic zone which surrounds the inclusions. This mechanism seems to be more effective than the direct nucleation of the second phase on the inclusion interface and has important implications for the problem of acicular ferrite formation in carbon steels.

A enfermagem de saúde pública no controle da hanseníase: conhecimento do pessoal de enfermagem

Abstract: This work is a report of a research carried out in the Sanitary Dermatology -Leprosy area of the Health Centers from the Regional Health Department of Ribeirao Preto, State Health Bureau of Sao Paulo State. The investigation pointed out the knowledge of nursing personal which directly operated in the area, establishing that the correct knowledge ranged from 86,8% to 60,4% for "notions on the illness" and "notions on experiments and tests" items, having the complete answers also presented coefficient superior to the incomplete ones. However, the number of "wrong" and "doesn't know" answers were significant, according to the classification carried through each item.

Gestão tradicional e obstáculos ao crescimento empresarial: um estudo de caso entre imigrantes empresários

Abstract: Grosso modo, a maior parte dos autores interessados no florescimento industrial paulista está de acordo em ver no abalo sofrido pela economia cafeeira no início dos anos 30o surgimento do novo padrão de acumulação industrial. Do ponto de vista da localização do pólo nervoso dessa nova economia, é também sabido que a cidade de São Paulo desde logo tomou para si o papel de centro decisório e condutor deste processo: havendo anteriormente aglutinado as funções comerciais, de financiamento e de promoção da infra-estrutura necessária ao café, reuniu as melhores condições de nuclear, numa fase seguinte, o grosso da indústria paulista. Entretanto, mesmo que a industrialização promovida daí por diante sempre se encontrasse fortemente polarizada pela capital, as condições geradas pela economia cafeeira na fase anterior garantiriam a extensão ao interior paulista da acumulação industrial que era então inaugurada. Desenvolveram-se alguns núcleos urbanos onde a cultura do café tinha anteriormente deitado suas raízes, formando-se o que depois se convencionou denominar cidades médias paulistas. Neste processo de industrialização interiorano, não foram raros os núcleos que, como São Carlos" tiveram como protagonistas principais do desenvolvimento industrial alguns imigrantes.' Este artigo resulta de um estudo de caso.ê através do qual se buscou analisar o comportamento e a mentalidade empresariais desses imigrantes, explicitando sua racionalidade em determinada época e sugerindo que estes fatores podem ter estabelecido limitesmuito precisos ao crescimento de suas empresas numa etapa subseqüente do desenvolvimento econômico e social. Não me deterei sobre as condições econômicas e sociais, já analisadas em outro local, que balizaram a ação empresarial desses imigrantes.! É impossível dissociar desta ação tanto as demandas e oportunidades surgidas no período do café, pelo lado da economia, quanto a própria origem e trajetórias sociais desses imigrantes e, portanto, os trunfos de que dispunham para a ascensão social. Tendo isto presente, nosso intuito aqui será o de precisar o modo de empreender, os valores e a visão do mundo do empreendedor porque eles "realizam e exprimem a produção, a distribuição e a acumulação, tal como são tomadas possíveis num dado momento do desenvolvimento social.t'

Biologia e ontogenia de Trachyderes striatus (Fabricius) (Coleoptera, Cerambycidae)

Abstract: In this paper larval and pupal stages of Trachyderes striatus (Fabricius) are described. Some aspects of its biology are added.

Semiempirical relationship for the total cross section for electron scattering in atoms and molecules

Abstract: Total cross section values for electrons scattered by atoms and molecules can be obtained by adding the total inelastic cross section to the total differential elastic cross section. We compare these values with experimental values for nitrogen and carbon dioxide. For methane, we compare with experimental values from positron scattering. The agreement is excellent for nitrogen between 40 and 1500 eV and for carbon dioxide between 100 and 500 eV.