Propriedades física de molécilas orgânicas e compostos do tipo perovskita CdSiO3 e CaPbO3

In the first part of this work our concern was to investigate the thermal effects in organic crystals using the theory of the polarons. To analyse such effect, we used the Fröhlich s Hamiltonian, that describes the dynamics of the polarons, using a treatment based on the quantum mechanics, to elucidate the electron-phonon interaction. Many are the forms to analyzing the polaronic phenomenon. However, the measure of the dielectric function can supply important information about the small polarons hopping process. Besides, the dielectric function measures the answer to an applied external electric field, and it is an important tool for the understanding of the many-body effects in the normal state of a polaronic system. We calculate the dielectric function and its dependence on temperature using the Hartree-Fock decoupling method. The dieletric function s dependence on the temperature is depicted by through a 3D graph. We also analyzed the so called Arrhenius resistivity, as a functionof the temperature, which is an important tool to characterize the conductivity of an organic molecule. In the second part we analyzed two perovskita type crystalline oxides, namely the cadmium silicate triclinic (CdSiO3) and the calcium plumbate orthorhombic (CaPbO3), respectively. These materials are normally denominated ABO3 and they have been especially investigated for displaying ferroelectric, piezoelectric, dielectrics, semiconductors and superconductors properties. We found our results through ab initio method within the functional density theory (DFT) in the GGA-PBE and LDA-CAPZ approximations. After the geometry optimization for the two structure using the in two approximations, we found the structure parameters and compared them with the experimental data. We still determined further the angles of connection for the two analyzed cases. Soon after the convergence of the energy, we determined their band structures, fundamental information to characterize the nature of the material, as well as their dielectrics functions, optical absorption, partial density of states and effective masses of electrons and holes

Cálculos AB initio de propriedades estruturais, eletrônicas e ópticas de colmpostos CaXo3 (X=Si, Ge, Sn)

In this work we present a study of structural, electronic and optical properties, at ambient conditions, of CaSiO3, CaGeO3 and CaSnO3 crystals, all of them a member of Ca-perovskite class. To each one, we have performed density functional theory ab initio calculations within LDA and GGA approximations of the structural parameters, geometry optimization, unit cell volume, density, angles and interatomic length, band structure, carriers effective masses, total and partial density of states, dielectric function, refractive index, optical absorption, reflectivity, optical conductivity and loss function. A result comparative procedure was done between LDA and GGA calculations, a exception to CaSiO3 where only LDA calculation was performed, due high computational cost that its low symmetry crystalline structure imposed. The Ca-perovskite bibliography have shown the absence of electronic structure calculations about this materials, justifying the present work

Sistemas Nanoestruturados: Heteroestruturas Quasi-Periódicas de Nitretos e Cálculos Ab initio em Polimorfos CaCO3

The physical properties and the excitations spectrum in oxides and semiconductors materials are presented in this work, whose the first part presents a study on the confinement of optical phonons in artificial systems based on III-V nitrides, grown in periodic and quasiperiodic forms. The second part of this work describes the Ab initio calculations which were carried out to obtain the optoeletronic properties of Calcium Oxide (CaO) and Calcium Carbonate (CaCO3) crystals. For periodic and quasi-periodic superlattices, we present some dynamical properties related to confined optical phonons (bulk and surface), obtained through simple theories, such as the dielectric continuous model, and using techniques such as the transfer-matrix method. The localization character of confined optical phonon modes, the magnitude of the bands in the spectrum and the power laws of these structures are presented as functions of the generation number of sequence. The ab initio calculations have been carried out using the CASTEP software (Cambridge Total Sequential Energy Package), and they were based on ultrasoft-like pseudopotentials and Density Functional Theory (DFT). Two di®erent geometry optimizations have been e®ectuated for CaO crystals and CaCO3 polymorphs, according to LDA (local density approximation) and GGA (generalized gradient approximation) approaches, determining several properties, e. g. lattice parameters, bond length, electrons density, energy band structures, electrons density of states, e®ective masses and optical properties, such as dielectric constant, absorption, re°ectivity, conductivity and refractive index. Those results were employed to investigate the confinement of excitons in spherical Si@CaCO3 and CaCO3@SiO2 quantum dots and in calcium carbonate nanoparticles, and were also employed in investigations of the photoluminescence spectra of CaCO3 crystal

Efeitos não-gaussianos em astrofísica e cosmologia

The recent astronomical observations indicate that the universe has null spatial curvature, is accelerating and its matter-energy content is composed by circa 30% of matter (baryons + dark matter) and 70% of dark energy, a relativistic component with negative pressure. However, in order to built more realistic models it is necessary to consider the evolution of small density perturbations for explaining the richness of observed structures in the scale of galaxies and clusters of galaxies. The structure formation process was pioneering described by Press and Schechter (PS) in 1974, by means of the galaxy cluster mass function. The PS formalism establishes a Gaussian distribution for the primordial density perturbation field. Besides a serious normalization problem, such an approach does not explain the recent cluster X-ray data, and it is also in disagreement with the most up-to-date computational simulations. In this thesis, we discuss several applications of the nonextensive q-statistics (non-Gaussian), proposed in 1988 by C. Tsallis, with special emphasis in the cosmological process of the large structure formation. Initially, we investigate the statistics of the primordial fluctuation field of the density contrast, since the most recent data from the Wilkinson Microwave Anisotropy Probe (WMAP) indicates a deviation from gaussianity. We assume that such deviations may be described by the nonextensive statistics, because it reduces to the Gaussian distribution in the limit of the free parameter q = 1, thereby allowing a direct comparison with the standard theory. We study its application for a galaxy cluster catalog based on the ROSAT All-Sky Survey (hereafter HIFLUGCS). We conclude that the standard Gaussian model applied to HIFLUGCS does not agree with the most recent data independently obtained by WMAP. Using the nonextensive statistics, we obtain values much more aligned with WMAP results. We also demonstrate that the Burr distribution corrects the normalization problem. The cluster mass function formalism was also investigated in the presence of the dark energy. In this case, constraints over several cosmic parameters was also obtained. The nonextensive statistics was implemented yet in 2 distinct problems: (i) the plasma probe and (ii) in the Bremsstrahlung radiation description (the primary radiation from X-ray clusters); a problem of considerable interest in astrophysics. In another line of development, by using supernova data and the gas mass fraction from galaxy clusters, we discuss a redshift variation of the equation of state parameter, by considering two distinct expansions. An interesting aspect of this work is that the results do not need a prior in the mass parameter, as usually occurs in analyzes involving only supernovae data.Finally, we obtain a new estimate of the Hubble parameter, through a joint analysis involving the Sunyaev-Zeldovich effect (SZE), the X-ray data from galaxy clusters and the baryon acoustic oscillations. We show that the degeneracy of the observational data with respect to the mass parameter is broken when the signature of the baryon acoustic oscillations as given by the Sloan Digital Sky Survey (SDSS) catalog is considered. Our analysis, based on the SZE/X-ray data for a sample of 25 galaxy clusters with triaxial morphology, yields a Hubble parameter in good agreement with the independent studies, provided by the Hubble Space Telescope project and the recent estimates of the WMAP

Não-extensividade em percolação por ligações de longo - alcance

A linear chain do not present phase transition at any finite temperature in a one dimensional system considering only first neighbors interaction. An example is the Ising ferromagnet in which his critical temperature lies at zero degree. Analogously, in percolation like disordered geometrical systems, the critical point is given by the critical probability equals to one. However, this situation can be drastically changed if we consider long-range bonds, replacing the probability distribution by a function like . In this kind of distribution the limit α → ∞ corresponds to the usual first neighbor bond case. In the other hand α = 0 corresponds to the well know "molecular field" situation. In this thesis we studied the behavior of Pc as a function of a to the bond percolation specially in d = 1. Our goal was to check a conjecture proposed by Tsallis in the context of his Generalized Statistics (a generalization to the Boltzmann-Gibbs statistics). By this conjecture, the scaling laws that depend with the size of the system N, vary in fact with the quantitie

Correlação entre torque, equlíbrio e função do joelho após reconstrução do LCA

Background: Several studies emphasize the importance of assessing the knee function after anterior cruciate ligament (ACL) reconstruction. The influence of several variables on the function of these patients has been analyzed, but there is no consensus in the science literature. Purpose: To evaluate the correlation between the torque and balance on the knee function after ACL reconstruction. Methods: 23 males patients with ACL reconstruction were tested. The procedures of the study included analysis of concentric peak torque at 60o/s and 180o/s of quadriceps femoris and hamstring muscle with a isokinetic dynamometer. The balance in single-limb stance was measured with stabilometry. The functional performance were performed by two hop tests. To estimate the subjective function of the patients was applied Lysholm Knee Scoring Scale and a Global Rating scale. Results: The analysis of data showed a moderate positive correlation between knee extensor torque and functional performance tests (r= 0,48; p=0,02). A moderate negative correlation was found between the two variables of the stabilometry center of pressure and average speed of centre of pressure and the Global Rating scale (r = -0.4, p = 0,04 and r = -0,49, p = 0 ,02, respectively). No correlation was found between peak torque and balance in single-limb stance. Conclusion: The results of the present study suggest that knee extensor strength and postural balance have some influence on knee function in patients after ACL reconstruction

Avaliação da função pulmonar em obesos mórbidos com sonolência diurna excessiva

Background: Obesity impairment to the pulmonary function related to the magnitude of adiposity and is associated with excessive daytime sleepiness (EDS) and snoring, among others symptoms of respiratory disorders related to sleep. It is possible that obese individuals with excessive daytime sleepiness may make changes in lung function on spirometry monitored during the day as a consequence of fragmented sleep or episodes of nocturnal hypoventilation that cause respiratory and changes that can persist throughout the day. The combination of these findings alone sleepiness observed by subjective scales with pulmonary function in obese patients is unknown. Objective: To assess the influence of EDS and snoring on pulmonary function in morbidly obese and distinguish between different anthropometric markers, the snoring and sleepiness which the best predictors of spirometric function and respiratory muscle strength and endurance of these patients. Methods: We evaluated 40 morbidly obese markers on the anthropometric, spirometric respiratory variables, maximal inspiratory and expiratory pressures (MIP and MEP) and maximal voluntary ventilation (MVV) and the measured excessive daytime sleepiness (the Epworth sleepiness scale) and snoring (snoring scale of Stanford). The data were treated when the differences between the groups of obese patients with and without sleepiness, whereas the anthropometric variables, respiratory and snoring. Pearson's correlation was performed, and multiple regression analysis assessed the predictors of pulmonary function. For this we used the software SPSS 15.0 for windows and p <0.05. Results: 39 obese patients were included (28 women), age 36.92+11.97y, body mass index (BMI) 49.3+5.1kg/m², waist-hip ratio (WHR) 0.96+0.07 and neck circumference (NC) 44.1+4.2 cm. Spirometric values and respiratory pressures were up 80% of predicted values, except for endurance (MVV <80%). Obese with EDS have lower tidal volume. Positive correlation was observed between BMI and EDS, EDS and NC and between snoring and BMI, and negative correlation between EDS and tidal volume (TV), and between snoring and snoring FVC and FEV1. In linear regression the best predictor of pulmonary function was snoring, followed by NC. NC has more obese with higher strength (MEP, p = 0.031) and endurance (MVV p = 0.018) respiratory muscle. Conclusion: Obese with EDS tend to have lower TV. In addition, snoring and NC can better predict pulmonary function in obese when compared with other anthropometric markers or EDS. Obese patients with higher NC tend to have greater capacity for overall strength of respiratory muscles, but may have low muscle endurance

Análise da função dos músculos do quadril em portadores de síndrome da dor patelofemural

The Patellofemoral pain syndrome is defined as a fore or retro patellar pain and it has multifactorial etiology, where the bad patellar alignment is the most acceptable hypothesis. However proximal factors to the knee, as the debility of the muscles of the hip, have been demonstrated as a contributing factor to the appearing of that syndrome. Purpose: To evaluate if exists a relation between the hip muscles performance and the development of the SDPF. Methods: Thirty women took part in this study. They were divided in two groups; a control group (fifteen asymptomatic subjects) and an experimental group (fifteen subjects with the diagnosis of SDPF). The muscle performance was evaluated in an isokinetic dynamometer, where it was verified the peak torque (PT), PT to body weight, PT time and the agonist/antagonist relation. It was also analyzed the electromyographic activity of the middle gluteus. The data was analyzed by the not paired t test at a significance level of 5%. Results:. Didn t have significant difference to the PT of the abductor muscles (p = 0,46) and lateral rotators of the hip (p = 0,17) between groups. Also didn t have significant difference to the PT values by the body weight, to these muscle groups either (p = 0,10 e p = 0,11, respectively). Didn t have significant difference between the amplitude of the signal (p = 0,05) and the onset of medium gluteus (p = 0,25) between the groups. Conclusion: In the experimental conditions realized, the study didn t demonstrate a relation between performance the hip muscles behavior and the development of the SDPF

Efeitos da perda de peso induzida pela cirurgia bariátrica sobre a função respiratória

Background: Obesity leads to alteration of lung volumes and capacities due to accumulation of fat in the chest wall and abdomen. Few studies have shown that weight loss induced by surgery improves lung function. Our objective was to evaluate the anthropometric development, pulmonary function, respiratory muscle, strength and endurance after weight loss induced by bariatric surgery. Methods: We evaluated in pre and post operative period variables of weight, BMI, NC, WHR and spirometric and respiratory pressure. Results: 39 subjects were evaluated, with age mean 35.9 ± 10.9 years, predominantly by women (76.3%). The weight mean decreased from 124.8 ± 17.5 kg to 88.8 ± 14.28 kg in post operative. The mean BMI ranged from 47,9 ± 5,6 Kg/m² to 34,3 ± 4,75 Kg/m². There was a significant increase in FVC from 3,63 ± 0,94 to 4,01±1,03, FEV1 from 3,03 ± 0,72 to 3,39 ± 0,85, FEF 25-75% from 3,41 ± 0,72 to 3,82 ± 0,94, PEF from 6,56 ± 1,47 to 7,81 ± 1,69, ERV from 0,35 ± 0,39 to 0,66 ± 0,38, MVV ranged from 103,43 ± 22,21 to 137,27 ± 29,84, all of them to p<0,01. The MIP and MEP showed no significant difference in pre and post operative. It was noted that for every centimeter reduced in neck circumference, an increase of 0.06 in FVC and 5.98 in MVV is observed. This is also observed in weight and BMI. Conclusion: We conclude that weight loss induced by bariatric surgery in obese provides a significant improvement in lung function and reduction of fat around the neck is more important in the generation of lung volume than the reduction of BMI

Influência do kinesio taping® no desempenho neuromuscular do quadríceps femoral e na função do membro inferior em sujeitos saudáveis: ensaio clínico, controlado, randomizado, cego

Objective:To analyze the immediate effects of the Kinesio Taping® application on the quadriceps neuromuscular performance, postural balance and lower limb function in healthy subjects. Materials andmethods:This is a randomized, controlled, blinded clinical trial. Sixtyfemale volunteers(age: 23.3±2.5 years old, BMI: 22.2±2.1kg/m2)wererandomly assigned intothreegroups with20memberseach,and performedone of these threeprotocols: control -10 minutesof rest,experimental 1- patch application ontherectusfemoris (RF), vastuslateralis(VL) and vastusmedialis(VM) and experimental 2-KT application on the same muscles. Allunderwent an evaluationfor singleand triple hop distance, postural balance (baropodometry), joint position sense(JPS), peak torque (concentric and eccentricevaluation at 60°/s)and electromyographic activityof VL,before andafter intervention.Results: There wasasignificant increasein the jump distanceof thethreestudied groups,with no differencebetween groups.There were nosignificant changesin postural balance,JPS, concentricpeak torqueand RMSof the VLin none of the groups. There was a reduction ineccentricpeak torquein all groups, without differencesbetween groups.Conclusion:The KT application on the RF, VL and VMmusclesis not able tosignificantly improvelower limbfunction and postural balance, as well as the kneeextensor peaktorque, JPSand the VL muscleactivation amplitudeof healthy women.

Função pulmonar de crianças com leucemia aguda

Introduction: The leukemias are the most common malignancy in children and adolescents. With the improvement in outcomes, there is a need to consider the morbidity to generate the protocols used in children under treatment. Aim: To evaluate pulmonary function in children with acute leukemia. Method: This study is an observational cross sectional. We evaluated 34 children distributed in groups A and B. Group A comprised 17 children with acute leukemia in the maintenance phase of chemotherapy treatment and group B with 17 healthy students from the public in the city of Natal / RN, matched for gender, age and height. The thoracic mobility was evaluated by thoracic expansion in the axillary and xiphoid levels. Spirometry was measured using a spirometer Microloop Viasys ® following the rules of the ATS and ERS. Maximal respiratory pressures were measured with digital manometer MVD300 (Globalmed ®). The maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured from residual volume and total lung capacity, respectively. The data were analyzed using the SPSS 17.0 software assigning the significance level of 5%. Descriptive analysis was expressed as mean and standard deviation. T'student test was used to compare unpaired values found in group A with group B values, as well as with the reference values used. To compare the respiratory coefficients in the axillary level with the xiphoid in each group, we used paired testing t student. Results: Group A was significantly decreased thoracic mobility and MIP compared to group B, and MIP compared to baseline. There was no significant difference between spirometric data from both groups and the values of group A with the reference values Mallozi (1995). There was no significant difference between the MIP and MEP values and lower limits of reference proposed by Borja (2011). Conclusion: Children with acute leukemia, myeloid or lymphoid, during maintenance phase of chemotherapy treatment have reduced thoracic mobility and MIP. However, to date, completion of clinical treatment, the spirometric variables and the strength of the expiratory muscles appear to remain preserved in children between five and ten years

Fluxo de potência ótimo reativo via método da função lagrangiana barreira modificada

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

Parahyba ou João Pessoa? Um estudo sobre a função social da História

Este trabalho é uma discussão sobre as funções sociais da História e da Memória. Para tanto, foi pensado diante do 80º aniversário da Revolução de 1930, marco da (re)fundação da capital paraibana, pois esta memória e a produção historiográfica a respeito do tema nos é bastante instigante. Falar de João Pessoa, seja da cidade, seja do indivíduo; no que se refere aos episódios de 1930, é tocar em um assunto bastante passional, onde chegar a um consenso é algo extremamente improvável. O objetivo deste trabalho é problematizar as funções sociais da História e suas utilizações, notadamente por meio do nosso objeto de estudo, buscando contribuir para a compreensão de como a memória e a escrita da História são frutos do trabalho constante das sociedades que as engendram. Estudar sobre a produção da memória e da historiografia bem como a função da escrita da História sobre esses episódios, entendendo-os como espaços específicos de disputas, notadamente sobre os embates de memórias nos últimos dez anos, trazendo novas reflexões sobre as funções sociais destas memórias

Caracterização estatística de processos sísmicos via Distribuição Generalizada de Pareto. Estudo de caso: João Câmara-RN

The work is to make a brief discussion of methods to estimate the parameters of the Generalized Pareto distribution (GPD). Being addressed the following techniques: Moments (moments), Maximum Likelihood (MLE), Biased Probability Weighted Moments (PWMB), Unbiased Probability Weighted Moments (PWMU), Mean Power Density Divergence (MDPD), Median (MED), Pickands (PICKANDS), Maximum Penalized Likelihood (MPLE), Maximum Goodness-of-fit (MGF) and the Maximum Entropy (POME) technique, the focus of this manuscript. By way of illustration adjustments were made for the Generalized Pareto distribution, for a sequence of earthquakes intraplacas which occurred in the city of João Câmara in the northeastern region of Brazil, which was monitored continuously for two years (1987 and 1988). It was found that the MLE and POME were the most efficient methods, giving them basically mean squared errors. Based on the threshold of 1.5 degrees was estimated the seismic risk for the city, and estimated the level of return to earthquakes of intensity 1.5°, 2.0°, 2.5°, 3.0° and the most intense earthquake never registered in the city, which occurred in November 1986 with magnitude of about 5.2º

Pecolação em uma rede multifractal

In this work we present the principal fractals, their caracteristics, properties abd their classification, comparing them to Euclidean Geometry Elements. We show the importance of the Fractal Geometry in the analysis of several elements of our society. We emphasize the importance of an appropriate definition of dimension to these objects, because the definition we presently know doesn t see a satisfactory one. As an instrument to obtain these dimentions we present the Method to count boxes, of Hausdorff- Besicovich and the Scale Method. We also study the Percolation Process in the square lattice, comparing it to percolation in the multifractal subject Qmf, where we observe som differences between these two process. We analize the histogram grafic of the percolating lattices versus the site occupation probability p, and other numerical simulations. And finaly, we show that we can estimate the fractal dimension of the percolation cluster and that the percolatin in a multifractal suport is in the same universality class as standard percolation. We observe that the area of the blocks of Qmf is variable, pc is a function of p which is related to the anisotropy of Qmf