On the dynamic behaviour of a nonlinear system weakly connected to a linear single degree-of-freedom system

This paper discusses the dynamic behaviour of a nonlinear two degree-of-freedom system consisting of a harmonically excited linear oscillator weakly connected to a nonlinear attachment that behaves as a hardening Duffing oscillator. A system which behaves in this way could be a shaker (linear system) driving a nonlinear isolator. The mass of the nonlinear system is taken to be much less than that in the linear system and thus the nonlinear system has little effect on the dynamics of the linear system. Of particular interest is the situation when the linear natural frequency of the nonlinear system is less than the natural frequency of the linear system such that the frequency response curve of the nonlinear system bends to higher frequencies and thus interacts with the resonance frequency of the linear system. It is shown that for some values of the system parameters a complicated frequency response curve for the nonlinear system can occur; closed detached curves can appear as a part of the overall amplitude-frequency response. The reason why these detached curves appear is presented and approximate analytical expressions for the jump-up and jump-down frequencies of the system under investigation are given.

Estudo das propriedades estruturais e ópticas de vidros teluritos do sistema TeO2-Li2O-Nb2O5

Pós-graduação em Ciência dos Materiais - FEIS

Polimorfismo da haptoglobina correlacionado com doença arterial coronariana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Síntese, caracterização e investigação da atividade biológica de complexos de cobre e paládio contendo ligantes N,S doadores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Padrões de esterases em populações resistentes e suscetíveis de Aedes aegypti (Diptera, Culicidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese, caracterização e avaliação da citotoxidade de complexos de 'Pd'(II) contendo o ligante 4,4´,5,5´ - tetrametil-2,2´-bis-imidazol

Pós-graduação em Química - IQ

Padrões de diversidade e estrutura de taxocenoses de anfíbios anuros: análise em multi-escala espacial

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Propiedades Eléctricas en Membranas de Complejos Electrolitos Poliméricos PVA-OH/LI2SO4/PEG400

Lithium ion conducting polymer electrolytes based on polyvinyl Alcohol (PVA-OH) complexed with salt Li2SO4 and different weight percent ratios of PEG(400) plasticizer have been prepared by solution cast technique using deionized water as solvent. The thermogravimetric analysis (TGA) showed that the thermal stability of the materials depended on the plasticizer content. The FTIR study confirmed the polymer salt complex formation. The modulus spectra indicated the non-Debye nature of the material; a dominant relaxation process is visible being associated with the dynamic glass transition, relaxation-a. The maximum of each peak is shifted to higher frequencies as the plasticizer increases due to an enhancement of dipolar mobility in the origin of cooperative motions. A power law frequency dependence of the real part of the electrical conductivity is observed, which is characteristic of the effects of ion-ion and/or ion-chain correlations in ion motion. This variation is well fitted to a Jonscher's expression.

Polymorphisms in endothelial nitric oxide synthase gene in early and late severe preeclampsia

Preeclampsia (PE) is characterized by hypertension and proteinuria, occurring after the 20th week of pregnancy in women who have had no previous symptoms. The disease progresses with generalized vasoconstriction and endothelial dysfunction. Clinically, it is important to diagnose the severe form of the disease (sPE), in which blood pressure and proteinuria are much higher. Recently, the gestational age (GA) of the onset of PE has led to the classification of this disease as early (GA <34 weeks) and late (GA >= 34 weeks). Several genetic polymorphisms affecting endothelial nitric oxide synthase (eNOS) levels or function were described, including G894T (Glu298Asp), VNTR b/a (variable-number 27-bp tandem repeat) and T-786C (promoter) polymorphisms. Thus, the aim of this study was to compare the distribution of G894T, VNTR b/a and T-786C polymorphisms and their haplotypes in Brazilian early and late sPE, as well as in normotensive pregnant. A total of 201 women were evaluated, 53 with early sPE, 45 with late sPE and 103 as normotensive pregnant women. The frequency of 894T allele was higher in late sPE vs normotensive pregnant, and 894TT genotype was higher in late sPE vs early sPE and normotensive pregnant. For VNTR b/a polymorphism, higher frequencies of aa genotype and a allele were observed in early sPE vs late sPE and normotensive pregnant. Besides, the frequency of haplotype T-b-C was higher in late sPE vs early sPE and normotensive pregnant. Considering the results found for eNOS polymorphisms, it is possible to suggest that the functional alterations induced by these two polymorphisms may influence the time of severe PE onset, although both alterations are putatively associated with low NO bioavailability. However, other studies are necessary to validate these findings and clarify this issue. (C) 2014 Elsevier Inc. All rights reserved.

Estudo da associação de polimorfismos no gene MC1R com cor de pele e cor de cabelo para fins forenses

Melanin is a very important pigment to human species, and besides defining skin, eyes and hair color, it is also involved in sun exposure protection. This pigment is classified into two subtypes: pheomelanin, which is responsible for lighter pigmentation and eumelanin, the dark pigment related. Due to this type of melanin variation it is possible to found different phenotypes of hair and skin color. The genetics MC1R variations are described as the most important for diversity in pigmentation, and this gene is directly related to the complex process of melanin synthesis. The use of these variations to phenotype prediction using genetic information has been used in Europe countries to infer physical features from biological samples, with the purpose of directing searches of criminal suspects and victims identification. The aim of this study was to analyze 8 major MC1R polymorphisms in a sample of Brazilian individuals. Analyzing 91 individuals, we observed with higher frequencies the polymorphisms rs1805005:G>T, rs2228479:G>A and rs885479:G>A, which are related to skin and hair colors, as previously showed in literature. These data suggest the possibility of predicting phenotype from genetic polymorphisms in Brazilian population. However it will be necessary to analyze a larger number of individuals to be able to confirm these associations and to perform a more detailed statistical analysis

Estudo de um método automatizado para o cálculo da profundidade de visualização dos equipamentos de ultrassonografia

Ultrasound is the term that describes the sound waves with higher frequencies than human hearing. Ultrasound used in medical diagnosis is a modality based on the use of sound energy and the acoustic properties of the various parts of the body to produce images of stationary and moving tissues. However, despite the ease of use and security that this modality offers for not using ionizing radiation, one should ensure the accuracy and optimum performance of the equipment, which results in precise diagnoses. To accomplish that, periodic quality control tests must be performed, which include: physical and mechanical inspection of the equipment, image uniformity, depth of penetration/visualization, accuracy of distances, axial and lateral resolution, dead zone and doppler sensitivity. This work intends to study a computerized method for calculating the depth of penetration of ultrasound, comparing it to the observerdependent method currently used. The images were collected during the quality control tests of ultrasound equipment. The results of the comparison between the visual and computerized methods were not conclusive for selecting the safest methodology for obtaining the depth of visualization

Association of a Large Panel of Cytokine Gene Polymorphisms with Complications and Comorbidities in Type 2 Diabetes Patients

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação audiológica em pacientes com doenças reumáticas pediátricas

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

Avaliação de danos no material genético em anestesiologistas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variação bioacústica das vocalizações do complexo Taraba major (Vieillot, 1816) (Aves: Passeriformes: Thamnophilidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)