Papers by Vladimir Ferraz
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Celestial Mechanics & Dynamical Astronomy, 1994
It is known that an abridged case of the averaged planar general three-body problem, at first-ord... more It is known that an abridged case of the averaged planar general three-body problem, at first-order resonance, is analytically integrated, using an expansion of the disturbing function linear in the eccentricities. There exist different methods with the help of which the integration can be performed. For the first time Sessin and Ferraz-Mello in the years 1981–88 (Sessin, 1981, 1983; Ferraz-Mello and Sessin, 1984; Ferraz-Mello, 1987, 1988) did an analytic integration for the restricted elliptic three-body problem, in terms of the variablesK andH (K=ΣD j e j cos (ψ1−πj ),H=ΣD j e j sin (ψ1−πj ),D j = const, wheree j and πj are, respectively, the eccentricity and the longitude of the periapsis of thei-th planet, ψ1 is the Delaunay's anomaly), which is inconvenient for the analytical investigation of the evolution of the major semi-axesa j , the eccentricitiese j and the resonance phases ϕj =ψ1−πj . Later, a different method for the analytical integration of the general three-body problem, in the variablesa j ,e j and ϕj , was considered by the author (Shinkin, 1993). A disadvantage of both methods is the fact that they use non-canonical changes of variables. But there exists a third very beautiful canonical method of analytical integration of the general planetary problem, which is briefly considered in the present paper and allows us to describe the bifurcations of separatrices (i.e. appearance, disappearance, splitting and confluence of separatrices) separating the domains of libration and circulation of the resonance phase on the phase plane in the averaged planar general three-body problem at first-order resonance. The bifurcation parameter is analytically found and plays an important role in a qualitative description of all kinds of motion in the examined problem.
Physica A-statistical Mechanics and Its Applications, 1992
In this paper we discuss the solid-liquid interface which emerges from our dislocation theory of ... more In this paper we discuss the solid-liquid interface which emerges from our dislocation theory of melting. We analyse how the dislocation order parameter varies across this interface and study the stability of the obtained solutions. We calculate the correlation radius and discuss physical characteristics of the system as functions of the coupling parameter.
Water Air and Soil Pollution, 1999
Water samples were collected from 7 locations along major rivers of Piracicaba River basin for 22... more Water samples were collected from 7 locations along major rivers of Piracicaba River basin for 22 months. The 4 upstream points represent non-polluted sites and the 3 downriver points represent polluted sites. Due to sewage input, concentrations of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), major conservative cations and anions increased significantly in the polluted sites. The major increases were observed for sodium, chloride and sulfate. Nitrate was an exception for this pattern, with similar concentrations between polluted and non-polluted sites. The probable cause was reduction of nitrate to ammonium in the polluted sites, where anoxic conditions prevail. Most of the variables had an inverse correlation with water discharge, especially in the polluted points. The sewage load was diluted by precipitation and surface waters.
Obesity Surgery, 2011
Background Type 2 diabetes mellitus (T2DM) and class I obesity, which are pandemics of considerab... more Background Type 2 diabetes mellitus (T2DM) and class I obesity, which are pandemics of considerable socioeconomic importance, require new treatment modalities due to inadequate control through normal clinical conduct. The aim of the present study was to assess the efficacy and safety of Roux-en-Y gastric bypass (RYGB) in the control of T2DM in patients with a body mass index (BMI) of 30 to 35 kg/m2. Methods An observational, retrospective study was carried out at the Universidade Federal de Pernambuco—Brazil. Between 2002 and 2008, 27 patients were submitted to RYGB for the treatment of uncontrolled T2DM, with a mean follow-up period of 20 months. An assessment was performed of the complete resolution of T2DM [HbA1c < 6%/fasting plasma glucose (FPG) < 100 mg/dL/no diabetes medication] and glycemic control. The ethics committee of the university approved the study. Results RYGB led to the following results: (1) 23% weight reduction (p < 0.001), BMI stabilized at 25.6 kg/m2 in a mean of 12 months; (2) 46% reduction in glycemia and 27% reduction in HbA1c (p < 0.001); (3) 100% improvement in glycemia and 48% resolution of T2DM; (4) glycemic control was 74% without medication and 93% with medication and five patients required medication in addition to RYGB; (5) mean current FPG is 93 mg/dL and HbA1c is 6%; and (6) there were no severe complications or deaths. Conclusions RYGB is a safe and effective option in the treatment of uncompensated T2DM associated to class I obesity.
Atmospheric Environment, 2001
The influences of different kinds of anthropogenic activities on rainwater chemistry in a tropica... more The influences of different kinds of anthropogenic activities on rainwater chemistry in a tropical area were studied during one uninterrupted year at Piracicaba River Basin (Southeast Brazil). A total of 272 rainwater samples collected continuously from August 1997 to July 1998 at four different sites were analyzed for F À , CH 3 COO À , HCOO À , MSA, Cl À , NO 2 À , Br À , NO 3 À , SO 4 2À , C 2 O 4 2À , PO 4 3À , Na + , NH 4 + , K + , Mg 2+ , Ca 2+ , DOC (dissolved organic carbon), DIC (dissolved inorganic carbon), pH and conductivity. The most abundant ion was H + and rain acidity was significant at all sampling sites (average pH of 4.4-4.5). The sources of this free acidity differ among sites and appear to be correlated to the different land-uses. The composition of rainwater appeared to be controlled mostly by three sources: soil dust, sugar cane burning and industrial emissions. r
World Journal of Microbiology & Biotechnology, 2009
The production of lignocellulolytic enzymes by eleven basidiomycetes species isolated from two ec... more The production of lignocellulolytic enzymes by eleven basidiomycetes species isolated from two ecosystems of Georgia was investigated for the first time under submerged (SF) and solid-state fermentation (SSF) of lignocellulosic by-products. Notable intergeneric and intrageneric differences were revealed with regard to the extent of hydrolase and oxidase activity. Several fungi produced laccase along with hydrolases in parallel with growth during the trophophase, showing that the synthesis of this enzyme is not connected with secondary metabolism. The lignocellulosic substrate type had the greatest impact on enzyme secretion. Some of the substrates significantly stimulated lignocellulolytic enzyme synthesis without supplementation of the culture medium with specific inducers. Exceptionally high carboxymethyl cellulase (CMCase, 122 U ml−1) and xylanase (195 U ml−1) activities were revealed in SF of mandarin peelings by Pseudotremella gibbosa IBB 22 and of residue after ethanol production (REP) by Fomes fomentarius IBB 38, respectively. The SSF of REP by T. pubescens IBB 11 ensured the highest level of laccase activity (24,690 U l−1), whereas the SSF of wheat bran and SF of mandarin peels provided the highest manganese peroxidase activity (570–620 U l−1) of Trichaptum biforme IBB 117. Moreover, the variation of lignocellulosic growth substrate provides an opportunity to obtain enzyme preparations containing different ratios of individual enzymes.
Journal of Membrane Science, 2010
The characterization of commercial membranes used in the separation of refined soybean oil/n-buta... more The characterization of commercial membranes used in the separation of refined soybean oil/n-butane and n-hexane mixtures was studied in this work using different commercial ultrafiltration membranes, with cut-offs ranging from 1 to 5 kDa. The membranes were used in the permeation of refined soybean oil/pressurized n-butane mixtures at 1:3 (w/w) and 1:1 (w/w) mass ratios in a continuous tangential flow module and in the permeation of soybean oil/n-hexane mixtures in a dead-end flow module. The membranes were characterized by DSC (differential scanning calorimetry), FTIR (Fourier transform spectroscopy), contact angle measurement (Goniometer), zeta potential and SEM-EDS (scanning electron microscopy with X-ray microanalysis) aiming to better understanding the phenomena involved in the permeation process. Some membranes did not show any measurable permeation flux for refined soybean oil/n-butane mixtures, which may be related to their low hydrophobicity. Contact angle and zeta potential measurements showed that the membrane surface hydrophilicity changes after permeation. FTIR spectra showed that the membranes were fouled with oil even after washing with solvent. Results obtained in this work showed that permeation caused few modifications on the surfaces of the tested membranes at the experimental conditions investigated. It is shown that these polymeric membranes can be used in the separation of vegetable oils/organic solvents effectively without degradations.
RESUMO: Objetivo: O objetivo do presente estudo foi avaliar o quadro clínico, a incidência, os fa... more RESUMO: Objetivo: O objetivo do presente estudo foi avaliar o quadro clínico, a incidência, os fatores predisponentes e a evolução de pacientes com fitobezoar após Gastroplastia Vertical e Y de Roux. Método: No período de Novembro de 1997 à Janeiro de 2004, foram realizadas 512 operações para o tratamento da Obesidade mórbida, seguindo a técnica proposta por Fobi/Capella (Septação gástrica com reconstituição em Y de Roux Proximal). Em dez pacientes foram identificados fitobezoar. Resultados: A incidência de fitobezoar, causando algum tipo de obstrução gastrointestinal, foi de 1,95% (10/512). Todos os casos de fitobezoar estavam relacionados ao fio de sutura inabsorvível do tipo prolene. Sete pacientes apresentaram quadro semioclusivo e de obstrução intestinal e foram tratados com laparotomia exploradora, ressecção da anastomose enteroenteral e confecção de nova enteroenteroanastomose. Nos três pacientes com bezoar situado na anastomose gastrojejunal, a secção do fio e a retirada do corpo estranho foram realizadas por endoscopia digestiva alta. Conclusão: A confecção de anastomose intestinal com fio inabsorvível predispõe a formação de bezoar em pós-operatório de gastroplastia (Rev. Col. Bras. Cir. 2006; 33(1): 35-38).
Arquivos De Gastroenterologia, 2006
BACKGROUND: Correlation between infectious agents and linfoproliferative diseases are more stabli... more BACKGROUND: Correlation between infectious agents and linfoproliferative diseases are more stablished, over all virus and bacteria, through the activation of linfocytes. AIM: To describe six new cases, of a series of 254 patients (2,36%) with mansonic schistosomiasis, in the hepatosplenic form. METHODS: Six patients will be described, amongst the 254 carriers of mansonic schistosomiasis, in the hepatosplenic form, followed in the last 13 years. RESULTS: All the six cases had occurred in women. The histopathologic examinations had evidenced two cases of marginal splenic zone lymphomas, one of great cells with immunoblasts lymphomas, one diffuse lymphomas, a great cells malignant lymphomas, a great not clivads cells, and another case of Hodgkin. Half of the six evolved for the death 4-15 months after the diagnosis. The others three persist in accompaniment in the Oncology Division of the Clinics Hospital. CONCLUSION: The incidence of lymphomas in the 254 mansonic schistosomiasis patients followed in our clinic was of 2,36%. At last, this article intends to call the attention, for the occurrence of lymphomas, in the spleen of patients with mansonic schistosomiasis, in the hepatosplenic form.
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Papers by Vladimir Ferraz