Made available in DSpace on 2014-10-09T12:35:49Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:46Z (GMT). No. of bitstreams: 0 / Embora a terapia com uso de laser de baixa potência (TLBP) seja uma modalidade terapêutica amplamente estudada no meio científico, sua aplicação na clínica médica ainda gera controvérsias, já que a literatura reporta que a TLBP é capaz de promover a proliferação e diferenciação de células tumorais. O objetivo deste estudo foi avaliar os efeitos da TLBP no crescimento celular usando como modelo a linhagem B16F10 de melanoma murino em estado de homeostase e estado redox, além de verificar o comportamento quimiotáxico da linhagem B16F10 por meio do ensaio de migração transwell em resposta à TLBP em diferentes densidades de energia. Foram montados cinco grupos experimentais utilizando um laser de emissão vermelha em λ = 660 nm: Grupo controle (GC) onde nenhuma irradiação foi realizada; G30 (30J/cm2); G60 (60J/cm2); G90 (90J/cm2); G120 (120J/cm2); G150 (150J/cm2), com as respectivas doses utilizadas. Todos os experimentos foram realizados em triplicata e os resultados obtidos foram submetidos à análise estatística. Sob as condições experimentais deste estudo, nossos resultados mostram que a TLBP neste comprimento de onda não promoveu mudanças no metabolismo celular nos tempos de 48 h e 72 h, independente do estado nutricional. Foi possível observar mudança no padrão de comportamento quimiotáxico da linhagem celular B16F10 irradiadas com laser de emissão vermelha. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Ilza Maria Urbano Monteiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-14T22:30:01Z (GMT). No. of bitstreams: 1 Makuch_MariaValeriaBahamondes_M.pdf: 9936891 bytes, checksum: f5cea3f3dd8db3f9c34d0b9e9f0a4d3c (MD5) Previous issue date: 2006 / Resumo: Introdução: A osteoporose é uma doença sistêmica que afeta principalmente as mulheres. Alguns dos fatores que aceleram a aparição desta doença são a idade e o uso, por longa data, de métodos anticoncepcionais com somente progestágenos. O sistema intrauterino liberador de levonorgestrel (SIU-LNG) é um método difundido para a contracepção e o tratamento de diversas patologias ginecológicas. Na literatura não foram identificados estudos longitudinais prospectivos, com usuárias de longa data deste método, que avaliem seus efeitos sobre a densidade mineral óssea (DMO). Objetivos: Avaliar a DMO em usuárias do SIU-LNG aos sete anos de uso e comparar com elas mesmas aos 10 anos de uso e com um grupo-controle de usuárias de método anticoncepcional não hormonal. Sujeitos e métodos: do total de 37 mulheres que realizaram DMO no antebraço aos sete anos de uso do SIU-LNG, foi avaliada a DMO novamente aos 10 anos de uso. Cada usuária foi pareada com uma usuária de DIU TCu380A, com o mesmo tempo de uso, por idade (± 1 ano), índice de massa corporal (IMC; kg/m2) (± 1), cor da pele e número de gravidezes (± 1). A DMO foi avaliada no antebraço não dominante no rádio distal (midshaft ulna) e no rádio ultradistal usando double X-ray absorptiometry. Os dados foram avaliados pelos testes t de Student pareado, Wilcoxon, Snedecor (ANOVA) e Índice de correlação múltipla. Resultados: A DMO das usuárias do SIU-LNG aos 10 anos de uso foi estatisticamente similar que aos sete anos e similar que os seus controles, usuárias de DIU TCu380A, mesmo quando pareadas por idade (± 1 ano), índice de massa corporal [IMC; kg/m2, (± 1)], cor da pele e número de gestações (± 1). A maior DMO das usuárias do SIU-LNG aos 10 anos foi significativamente associada ao maior IMC (kg/m2) e maior DMO aos sete anos de uso. Conclusão: As DMO dos antebraços distal e ultradistal foram similares entre as usuárias do SIU-LNG aos sete e 10 anos de uso, e também quando comparadas com um grupo de não usuárias deste contraceptivo / Abstract: Introduction: Osteoporosis is a systemic disease which mainly affects women. Some of the factors which provoke an acceleration of the initiation of this disease were age and use for a long-term of progestin-only contraceptive methods. The levonorgestrel-releasing intrauterine system (LNG-IUS) is widely introduced method for contraception and for the treatment of several gynecological pathologies. On the literature we were unable to identify prospective studies with long-term users of this method which evaluated their effect upon bone mineral density (BMD). Objectives: To assess prospectively the BMD of users of the LNG-IUS at the 7th year of use and compare with the same women at the 10th year of use and with a control group of users of a non-hormonal contraceptive method. Materials and methods: A total of 37 women who performed a forearm BMD at the 7th year of use and again at the 10th year of use. Each woman was paired with a woman who had been using a copper IUD TCu380A for at least the same length of time, who never use an LNG-IUS matched by age (±1 year), body mass index (BMI; kg/m2) (±1), ethnicity, and number of pregnancies (±1). BMD was evaluated at the distal and the ultra-distal radius of the nondominant forearm using double X-ray absorptiometry. The data was evaluated trough t-Student test for paired samples, Wilcoxon, Snedecor (ANOVA) and multiple logistic regression. Results: The BMD of LNG-IUS users at the 10th year of use was statistically similar than themselves when use at the 7th year as well as similar as controls users of the TCu380A IUD even when paired by age (± 1 year), body mass index (BMI; Kg/m2, (± 1), race and number of pregnancies (± 1). Higher BMD of the LNG-IUS at the 10th year of use was significantly associated to a high BMI (Kg/m2) and higher BMD at the 7th year of use. Conclusions: Forearm BMD at distal and ultra-distal radius was similar among users of the LNG-IUS at the 7th and at the 10th year of use and was also similar when compared users with non-users of this contraceptive method / Mestrado / Tocoginecologia / Meste em Tocoginoclogia

M.Sc. / When a pure chromium single crystal is cooled through its Néel temperature, it undergoes a paramagnetic to a multi-wave vector incommensurate spin-density-wave magnetic transition. Should a chromium single crystal be cooled through its Neel temperature in the presence of a strong enough magnetic field, 4-5 T, then all the spin-density-wave vectors that occur as it undergoes the paramagnetic to incommensurate spin-density-wave magnetic transition, are forced to be aligned parallel to the direction of the applied magnetic field, producing what is called a single spin-density-wave wave vector state in the crystal. The single spin-density-wave wave vector state will remain in the crystal when the magnetic field is removed providing the crystal is not heated above its Neel temperature. If the crystal when in the single spin-density-wave wave vector state is orientated so that the single spin-density-wave wave vector is aligned perpendicular to the direction of an applied magnetic field, then the spin polarisation vectors of the magnetic moments will align themselves so that they are perpendicular to the applied magnetic field and perpendicular to the single wave vector, producing what is called a single spin-densitywave wave vector and single spin polarisation vector state in the crystal. There is a difference in value between the elastic constants measured when a chromium single crystal is in the single spin-density-wave wave vector state to the elastic constants measured when the crystal is in the multi-wave vector spin-density-wave state.When pure chromium is alloyed with other materials the topology of the Fermi surface is changed resulting in some of the alloys being able to undergo paramagnetic to commensurate spin-densitywave magnetic transitions, as well as being able to undergo commensurate spin-density-wave to incommensurate spin-density wave transitions. This study makes use of a magnetic field of strength 4.5 Tin an attempt to produce a single spin-density-wave wave vector state in a Cr + 0.3 at.% Ru and a Cr + 1.6 at.% Si single crystals. Both single crystals undergo paramagnetic to commensurate spin-density-wave transitions when cooled through their, respective Neel temperatures, as well as the Cr + 0.3 at.% Ru single crystal being able to undergo a commensurate spin-density-wave to an incommensurate spin-density-wave transition if cooled further, down to 77 K, well below it's Neel temperature. The effects of the applied magnetic field on the Cr + 0.3 at.% Ru and Cr + 1.6 at.% Si single crystals was determined by measuring the elastic constants of the respective crystals.

The first ground based observations of aeronomic phenomena in the South Atlantic Anomaly Region are presented. These data show that enhancements in foF2 and foE can be directly attributed to precipitated electron energy fluxes in the Anomaly Region. The regular occurrence of particle induced sporadic-E ionization is also presented together with the first measurable 391.4 nm airglow radiation of about 16 R. The first comprehensive survey of energy fluxes carried by energetic particles using satellites is also presented for both daytime and nighttime as well as the seasonal fluctuations. We found that the nocturnally precipitated electron energy fluxes varied between 1 x 10⁻⁴ and 38 x 10⁻⁴ erg cm²s⁻¹, depending upon magnetic activity and season, whereas the daytime precipitated electron energy fluxes tended to vary between 1 x 10⁻³ and 8 x 10⁻³ erg cm⁻²s⁻¹, with a tendency to decrease during magnetically active periods. Electron density and temperature contours as well as NO⁺ and 0⁺ ions contours for nighttime are also presented. The main conclusion of the study is that precipitating electrons provide a significant and sometimes dominant source of ionization in the ionosphere over the South Atlantic Anomaly Region.

This thesis describes the search for a temporal model for predicting the peak ionospheric electron density-(foF2). Existing models, such as the International Reference Ionosphere (IRI) and 8KYCOM, were used to predict the 12 noon foF2 value over Grahamstown (26°E, 33°8). An attempt was then made to find a model that would improve upon these results. The traditional method of linear regression was used as a first step towards a new model. It was found that this would involve a multi variable regression that is reliant on guessing the optimum variables to be used in the final equation. An extremely complicated modelling equation involving many terms would result. Neural networks (NNs) are introduced as a new technique for predicting foF2. They are also applied, for the first time, to the problem of determining the best predictors of foF2. This quantity depends upon day number, level of solar activity and level of magnetic activity. The optimum averaging lengths of the solar activity index and the magnetic activity index were determined by appling NNs, using the criterion that the best indices are those that give the lowest rms error between the measured and predicted foF2. The optimum index for solar activity was found to be a 2-month running mean value of the daily sunspot number and for magnetic activity a 2-day averaged A index was found to be optimum. In addition, it was found that the response of foF2 to magnetic activity changes is highly non-linear and seasonally dependent. Using these indices as inputs, the NN trained successfully to predict foF2 with an rms error of 0.946 MHz on the daily testing values. Comparison with the IRI showed an improvement of 40% on the rms error. It is also shown that the NN will predict the noon value of foF2 to the same level of accuracy for unseen data of the same type.

This thesis presents the results of torque magnetometry and resistivity measurements of the electronic structure of novel quantum materials, specifically using the techniques of quantum oscillations and angle-dependent magnetoresistance oscillations. Measurements of the Fermi surfaces of these materials, alongside comparisons to the electronic structure predicted by density functional theory calculations, can elucidate much about the novel physical properties they exhibit and the competing interactions which govern their phase diagrams. The first system studied is the Iron-based superconductor FeSe_1-xS_x, an isoelectronically doped version of a system of much current interest, FeSe. Doping up to x = 0.2 is found to suppress the structural transition in this system entirely, with superconductivity continually present at low temperatures. Shubnikov-de Haas measurements across this range find a small quasi-two dimensional Fermi surface that increases in size and warping continuously with doping, with orbital dependent effective masses that do not change significantly within the orthorhombic phase. The second material studied is the antiferromagnetic intermetallic CeZn₁₁ which, featuring an unpaired 4f electron, is considered a possible candidate for heavy fermion behaviour. De Haas-van Alphen oscillations are seen once the antiferromagnetic phase is suppressed, and comparable frequencies of oscillation are measured in the non-magnetic analogue LaZn11, although with relatively smaller effective masses. GGA+U calculations, once magnetic breakdown is considered, match well the measured frequencies, confirming CeZn₁₁ to be a localised moment system with the 4f electron well below the Fermi level. The final material studied is the transition metal dichalcogenide IrTe₂, which undergoes dimerisation upon cooling into a number of possible charge modulated structures. Low temperature de Haas-van Alphen measurements find multiple domains of a quasi-two dimensional Fermi surface, no longer perpendicular to the lattice planes. Angular-dependent magnetoresistance oscillations observe a similarly tilted quasi-one dimensional Fermi surface, again with many domains present. Together these measurements confirm the unusual dimensionality of the dimerised Fermi surface of IrTe₂.

From Introduction: The minimum in the scalar magnitude of the geographic total field, which lies off the coast of Brazil, allows the mirror points of trapped particles to dip low into the atmosphere over the South Atlantic Ocean, resulting in two regions of maximum intensity of preciptated particles in that region, one from the inner belt and one from the outer. High charged particle fluxes have been observed at low altitudes over these regions by satellites Sputnik 5 and 6 (Ginsburg et al, 1961) and Discoverer 31 (Seward and Kornblum, 1963) amongst others. The more southerly of these two regions acts as a sink for electrons from the outer radiation belt and will be referred to in what follows as the Southern Radiation Anomaly. Gladhill and van Rooyen (1963) predicted that the energy deposited in the upper atmosphere by these charged particles would be sufficient to give rise to enhanced geophysical effects such as auroral emission, X-rays and ionization and heating of the upper atmosphere in this region. Although some of these effects have been correlated with precipitated electrons, no definite relation had until now been established between ionospheric effects and precipitated particles. The aim of this thesis was to investigate such a relationship and the results were extremely successful. It will be shown conclusively in what follows, that the precipitation of electrons can account for the ionospheric disturbances defined by a disturbance criterion at all stations around L=4. Part I describes the exploration of the radiation belts and the magnetosphere with rockets and satellites. The resulting theoretical models based on the observations are discussed. A brief review is given of the work that has been done to date to derive equations for the loss and replenishment of particles in the belts. Because of the complexity of these and the number of doubtful factors involved, a simple model of injection of electrons into the outer belt is devised, giving average values of trapped and precipitated electron fluxes at any point around L=4. In Part II, this model is employed together with the disturbance criterion of Gledhill and Torr (1965) to examine the relationship between ionospheric disturbances and electron fluxes. Also the energy range of the precipitated particles is examined.

No description available.

Autoregressive models factorize a multivariate joint probability distribution into a product of one-dimensional conditional distributions. The variables are assigned an ordering, and the conditional distribution of each variable modelled using all variables preceding it in that ordering as predictors. Calculating normalized probabilities and sampling has polynomial computational complexity under autoregressive models. Moreover, binary autoregressive models based on neural networks obtain statistical performances similar to that of some intractable models, like restricted Boltzmann machines, on several datasets. The use of autoregressive probability density estimators based on neural networks to model real-valued data, while proposed before, has never been properly investigated and reported. In this thesis we extend the formulation of neural autoregressive distribution estimators (NADE) to real-valued data; a model we call the real-valued neural autoregressive density estimator (RNADE). Its statistical performance on several datasets, including visual and auditory data, is reported and compared to that of other models. RNADE obtained higher test likelihoods than other tractable models, while retaining all the attractive computational properties of autoregressive models. However, autoregressive models are limited by the ordering of the variables inherent to their formulation. Marginalization and imputation tasks can only be solved analytically if the missing variables are at the end of the ordering. We present a new training technique that obtains a set of parameters that can be used for any ordering of the variables. By choosing a model with a convenient ordering of the dimensions at test time, it is possible to solve any marginalization and imputation tasks analytically. The same training procedure also makes it practical to train NADEs and RNADEs with several hidden layers. The resulting deep and tractable models display higher test likelihoods than the equivalent one-hidden-layer models for all the datasets tested. Ensembles of NADEs or RNADEs can be created inexpensively by combining models that share their parameters but differ in the ordering of the variables. These ensembles of autoregressive models obtain state-of-the-art statistical performances for several datasets. Finally, we demonstrate the application of RNADE to speech synthesis, and confirm that capturing the phone-conditional dependencies of acoustic features improves the quality of synthetic speech. Our model generates synthetic speech that was judged by naive listeners as being of higher quality than that generated by mixture density networks, which are considered a state-of-the-art synthesis technique.

As early as 1896, around the time of the discovery of the electron by J.J. Thompson, Birkeland was led to propose that aurorae were caused by fast moving electrons or similarly charged particles emitted by the sun and 'sucked in towards' the auroral zones by the geomagnetic field. He later supported this idea by firing electrons at a dipole field surrounding a sphere covered with a fluorescent coating. Extensive ground based observations of auroral features eventually led, in 1950, to the initial direct evidence of the fact that auroral emissions are due to energetic charged particles, consisting partly of protons, entering the earth's atmosphere (Meinel, 1951). However, it was only in 1952 and 1953 that the first measurements of what was later interpreted as bremsstrahlung X- rays from precipitating electrons were made at auroral latitudes. (Meredith et aI, 1955) During the IGY, 1957 - 1958, a number of rockets were fired through and near, visible aurorae and large fluxes of low energy electrons were detected ... Intro., p. 1.