Estudo experimental e teórico das propriedades magnéticas e supercondutoras dos compostos borocarbetos da série Y(Ni 1-x Mn x) 2 B2 C com x = 0,0, 0,01, 0,025, 0,05, 0,10 e 0,15

Apresentamos neste trabalho os resultados de um estudo experimental e teórico dos compostos borocarbetos supercondutores da série Y(Ni1-xMnx)2B2C com x = 0; 0,01; 0,025; 0,05; 0,10; 0,15. A principal motivação para este trabalho foi investigar a estrutura eletrônica e a possível formação do momento magnético sobre os átomos de impureza de Mn nos compostos Y(Ni1- xMnx)2B2C. O aparecimento do momento magnético localizado no sítio da impureza possibilitou estudar a influência do Mn sobre o mecanismo de quebra de pares supercondutores e sobre as propriedades magnéticas do composto. Os borocarbetos são compostos de estrutura cristalina tetragonal de corpo centrado e altamente anisotrópicos (c/a~3). São intermetálicos de alta temperatura crítica supercondutora Tc, com forte acoplamento elétron-fonon. Em alguns casos podem apresentar ordem magnética, supercondutividade e também coexistência ou competição energética entre ambos. As medidas de transporte eletrônico, em função da temperatura, foram feitas utilizando-se um detector síncroton baseado na técnica de quatro pontos operando na faixa de 4,2K até 300K. Essas medidas possibilitaram o estudo das propriedades relacionadas ao transporte eletrônico na fase supercondutora. Na fase normal, extraiu-se a dependência em energia da função espectral de fonons α² F (ω) para alguns compostos da série estudada. As medidas magnéticas em função da temperatura e do campo magnético foram feitas utilizando-se um SQUID (Superconducting Quantun Interference Device – Quantun Design Model MPMS XL). Tais medidas permitiram a caracterização das propriedades magnéticas de nossas amostras. Em particular determinou-se o valor, em regime de saturação, do momento magnético associado ao sítio cristalino do Mn. Foram determinadas também as correntes críticas supercondutoras usando o Modelo de estado crítico de Bean e a variação da temperatura crítica supercondutora (Tc) com a mudança do campo externo aplicado. As medidas magnéticas permitiram a obtenção do diagrama que relaciona o campo crítico inferior (HC1) e a temperatura, variando-se a concentração do átomo dopante de manganês. Foi feito um esforço teórico no sentido de interpretar os resultados experimentais. Para isso foram usados três modelos: O modelo de estado crítico de Bean já citado acima e um modelo baseado na fórmula de Ziman usando uma aproximação para a função espectral de fonons para descrever a resistividade no regime de alta temperatura. Além disto, usou-se o modelo de duas sub-redes para a descrição do momento magnético das impurezas de Mn, em função da concentração, na série Y(Ni ) ( 2 ω α F 1-xMnx)2B2C.

Government policy and private investment in Brazil (1955/82)

The questlon of the crowding-out of private !nvestment by public expenditure, public investment in particular , ln the Brazilian economy has been discussed more in ideological terrns than on empirical grounds. The present paper tries to avoid the limitation of previous studies by estlmatlng an equation for private investment whlch makes it possible to evaluate the effect of economic policies on prlvate investment. The private lnvestment equation was deduced modifylng the optimal flexible accelerator medel (OFAM) incorporating some channels through which public expendlture influences privateinvestment. The OFAM consists in adding adjustment costs to the neoclassical theory of investrnent. The investment fuction deduced is quite general and has the following explanatory variables: relative prices (user cost of capitaljimput prices ratios), real interest rates, real product, public expenditures and lagged private stock of capital. The model was estimated for private manufacturing industry data. The procedure adopted in estimating the model was to begin with a model as general as possible and apply restrictions to the model ' s parameters and test their statistical significance. A complete diagnostic testing was also made in order to test the stability of estirnated equations. This procedure avoids ' the shortcomings of estimating a model with a apriori restrictions on its parameters , which may lead to model misspecification. The main findings of the present study were: the increase in public expenditure, at least in the long run, has in general a positive expectation effect on private investment greater than its crowding-out effect on priva te investment owing to the simultaneous rise in interst rates; a change in economlc policy, such as that one of Geisel administration, may have an important effect on private lnvestment; and reI ative prices are relevant in determining the leveI of desired stock of capital and private investrnent.

Wine classification by taste sensors made from ultra-thin films and using neural networks

This paper reports on a sensor array able to distinguish tastes and used to classify red wines. The array comprises sensing units made from Langmuir-Blodgett (LB) films of conducting polymers and lipids and layer-by-layer (LBL) films from chitosan deposited onto gold interdigitated electrodes. Using impedance spectroscopy as the principle of detection, we show that distinct clusters can be identified in principal component analysis (PCA) plots for six types of red wine. Distinction can be made with regard to vintage, vineyard and brands of the red wine. Furthermore, if the data are treated with artificial neural networks (ANNs), this artificial tongue can identify wine samples stored under different conditions. This is illustrated by considering 900 wine samples, obtained with 30 measurements for each of the five bottles of the six wines, which could be recognised with 100% accuracy using the algorithms Standard Backpropagation and Backpropagation momentum in the ANNs. (C) 2003 Elsevier B.V. All rights reserved.

Diel variation in abundance and size of the seabob shrimp Xiphopenaeus kroyeri (Crustacea, Penaeoidea) in the Ubatuba region, Southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Clinical and pathological assessment of 82 patients with cardiovascular diseases undergoing autopsy at the Hospital das Clínicas of the Faculdade de Medicina de Botucatu from 1988 to 1993

OBJECTIVE: To evaluated the clinical diagnostic, efficiency for basic death causes in patients dying of circulatory disease and de relative frequency of those diseases. METHODS: Analysis of medical record data of 82 patients, ages from 16 to 84 years old (68 over 40 years old), whose died of circulatory disease and had undergone necropsy in the period from 1988 to 1993 years in the University Hospital of Medicine Faculty of Botucatu-UNESP, Br. RESULTS: The functional class of patients were III or IV, in 78%, and 81.7% needed urgent hospitalization. By the clinical judgment the death were by ischemic heart disease in 32 (21 acute myocardial infarction), Chagas'disease in 12, valvopathy in 11, cardiomyopathy in 7, heart failure with no specification of cardiopathy in 11 and other causes in 9. At the necropsy the death cause was ischemic heart disease in 34 patients, valvopathy in 10, Chagas'disease in 10, cardiomyopathy in 5, and heart failure with no specification of cardiopathy in 2.The concordance taxes were in thhe same order: 94,6%, 90,0%, 83.3%, 71.4% and 28.5%. CONCLUSION: There was a great efficiency of clinical diagnosis for death cause in a general university hospital. The ischemic heart disease were the main causes of death.

Longitudinal study of the influence of removable partial denture and chemical control on the levels of Streptococcus mutans in saliva

Some studies have evaluated the salivary levels of mutans streptococci (MS) in removable partial denture (RPD) users. Saliva samples (2.0 mL) were obtained from 31 patients in six periods: (T0): immediately before installation of RPD; (T8): 8 days after T0; (T48): 48 days after T0; (T92): 92 days after T0; (T140): 140 days after T0 and (T189): 189 days after T0. The samples were vortexed and serially diluted from 10(-1) to 10(-6) in 0.05 m phosphate buffer (pH 7.4). From each dilution, 0.025 mL was plated on Mitis Salivarius Bacitracin (MSB). The plates were incubated in 5% CO2 at 37 degreesC for 72 h. There was an increase (t -test, P < 0.05) in the number of MS between periods T0 and T48 (mean/s.d., CFU mL(-1) of saliva): T0: 2.26/4.43 x 10(6) and T48: 0.47/1.48 x 10(8) . After this, intensive treatment with CHX was accomplished in 29 patients. Saliva samples were obtained after treatment in four periods: (T24 h): 24 h after T0; (T14): 14 days after T24 h; (T28): 28 days after T24 h, and (T63): 63 days after T24 h. The number of MS in saliva did not decrease (t -test, P > 0.05). A new CHX formulation was applied in 15 patients. Saliva samples were obtained in periods: (T0): before new CHX application; (T24 h): 24 h after T0 and (T82): 82 days after T0. The new CHX reduced MS levels in saliva: (mean/s.d., CFU mL(-1) of saliva): T0: 6.64/8.47 x 10(6) and T24 h: 3.2/4.27 x 10(5) (sign rank, P < 0.05). In conclusion, there was a significant increase in the number of MS in saliva after the installation of RPD. The intensive treatment with a properly formulated CHX was effective in the reduction of MS, between 24 h and 82 days after its application.

Cytotoxic Effects of Different Concentrations of a Carbamide Peroxide Bleaching Gel on Odontoblast-Like Cells MDPC-23

This study evaluated the cytotoxic effects of a carbamide peroxide (CP) bleaching gel at different concentrations on odontoblast-like cells. Immortalized cells of the MDPC-23 cell line (30,000 cells/cm(2)) were incubated for 48 h. The bleaching gel was diluted in DMEM culture medium originating extracts with different CP concentrations. The amount (mu g/mL) of hydrogen peroxide (H(2)O(2)) released from each extract was measured by the leukocrystal violet/horseradish peroxidase enzyme assay. Five groups (n = 10) were formed according to the CP concentration in the extracts: G1-DMEM (control); G2-0.0001 % CP (0.025 mu g/mL H(2)O(2)); G3-0.001% CP (0.43 mu g/mL H(2)O(2)); G4-0.01% CP (2.21 mu g/mL H(2)O(2)); and G5-0.1 % CP (29.74 mu g/mL H(2)O(2)). MDPC-23 cells were exposed to the bleaching gel extracts for 60 min and cell metabolism was evaluated by the NITT assay. Data were analyzed statistically by one-way ANOVA and Tukey's test (alpha = 0.05). Cell morphology was examined by scanning electron microscopy. The percentages of viable cells were as follows: G1, 100%; G2, 89.41%; G3, 82.4%; G4, 61.5%; and G5, 23.0%. G2 and G3 did not differ significantly (p > 0.05) from G1. The most severe cytotoxic effects were observed in G3 and G4. In conclusion, even at low concentrations, the CP gel extracts presented cytotoxic effects. This cytotoxicity was dose-dependent, and the 0.1% CP concentration caused the most intense cytopathic effects to the MDPC-23 cells. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9013: 907-912, 2009

The size of excavators within a polymorphic termite species governs tunnel topology

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Purification and characterization of an exo-polygalacturonase produced by Penicillium viridicatum RFC3 in solid-state fermentation

The pectinolytic enzyme obtained from Penicillium viridicatum RFC by solid-state fermentation was purified to homogeneity by pretreatment with kaolin (40 mg mL(-1) ) and ultrafiltration. followed by chromatography on a Sephadex G50 column. The apparent molecular weight of the enzyme was 24 kDa. Maximal activity occurred at pH 6.0 and at 60 degrees C. The enzyme proved to be an exo-polygalacturonase, releasing galacturonic acid by hydrolysis of highly esterified pectin. The presence of 10 mM Ba2+ increased the enzyme activity by 96% and its thermal stability by 30%. besides increasing its stability at acid pH. The apparent K-m with apple pectin as substrate was 1.82 mg mL(-1) and the V-max was 81 mu mol min(-1). (c) 2007 Elsevier Ltd. All rights reserved.

Avaliação da Gravidade Específica e de Outras Medidas Corporais e da Carcaça para Estimar a Composição Corporal de Novilhos Nelore

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cycloactive, aneugenic and clastogenic effects of Paracoccidioides brasiliensis exoantigen in human lymphocyte cultures

The in vitro effect of Paracoccidioides brasiliensis exoantigen on the human lymphocytes cell cycle and chromosomes was studied. Human peripheral blood lymphocyte cultures from ten healthy, white, non-smoking, non-related adult males (mean age 31·3 ± 8·2 years) were studied. Blood cultures were treated with three exoantigen concentrations (0·25, 2·50 and 10·00 μg ml -1). At least 1000 metaphases were analysed at each concentration, for evaluation of numerical and structural chromosome aberrations (cA) and 30 000 for mitotic index (MI). Among the treated cultures, statistically significant differences in the frequencies of MI and cA were not observed. Nevertheless, when compared with control cultures, they all showed a significantly lower frequency of MI and higher frequency of cA. It is suggested that the detected alterations were caused by the exoantigen, its fractions or its metabolites. © 1996 Informa UK Ltd All rights reserved.