Study of structural and photoluminescent properties of Ca8Eu2(PO4)(6)O-2

In this work it is presented for the first time the nanostructured hydroxyapatites doped with 0.5, 1.0 and 2.0 wt% of Eu3+ prepared at room temperature by the mechanical alloying technique. X-ray diffraction powder (XRD), infrared (IR) and Raman scattering spectroscopy, scanning electron microscopy (SEM), microhardness measurements as well as luminescent data of Eu3+ were used to investigate the structural and optical properties of these nanomaterials. The electrical and dielectrical analyses were used with the intention of having a better comprehension about the electromagnetic fields in pure and doped hydroxyapatites.

Behavioural Analysis of a Nonlinear Mechanical System Using Transient Trajectories

This work aims at a better comprehension of the features of the solution surface of a dynamical system presenting a numerical procedure based on transient trajectories. For a given set of initial conditions an analysis is made, similar to that of a return map, looking for the new configuration of this set in the first Poincaré sections. The mentioned set of I.C. will result in a curve that can be fitted by a polynomial, i.e. an analytical expression that will be called initial function in the undamped case and transient function in the damped situation. Thus, it is possible to identify using analytical methods the main stable regions of the phase portrait without a long computational time, making easier a global comprehension of the nonlinear dynamics and the corresponding stability analysis of its solutions. This strategy allows foreseeing the dynamic behavior of the system close to the region of fundamental resonance, providing a better visualization of the structure of its phase portrait. The application chosen to present this methodology is a mechanical pendulum driven through a crankshaft that moves horizontally its suspension point.

La última palabra en dosis mínima

In this article we rewiewed the indications of the low-dose hormone replacement therapy in post menopausal women. We evaluate the effects of this therapy on menopausal symptoms bone metabolism, cardiovascular risk and endometrial cancer. The low-dose hormone replacement therapy is satisfactory to relief menopausal symptoms and improves lipid profile preventing atherosclerosis. It does not increase the risk of hyperplasia or endometrial cancer when is associate with progestagens. The low dose hormone replacement therapy is also associate to improve bone mineral density but to have better comprehension about the effective action of the low dose hormone replacement therapy on bone, more studies evaluating the risk of fractures are necessary.

Conflitos conjugais e seus efeitos sobre o comportamento de crianças: Uma revisão teórica

Marital conflicts have been largely investigated in research, especially because of its impact on child development. Based on a literature review, this article aims to present some reflections about marital conflicts and its possible associations with children's behavior, particularly through parental practices. Emphasis is made on a systemic view of causality between marital conflict and child behavior, which offers a better comprehension of the family functioning. This perspective also allows us to enlarge the analysis scope beyond linear correlations between both variables.

Methodology for DSC calibration in high heating rates

Despite the large use of differential scanning calorimetry (DSC) technique in advanced polymer materials characterization, the new methodology called DSC in high heating rates was developed. The heating rate during conventional DSC experiments varying from 10 to 20°C.min-1, sample mass from 10 to 15mg and standard aluminum sample pan weighting, approximately, 27mg. In order to contribute to a better comprehension of DSC behavior in different heating rates, this work correlates as high heating rate influences to the thermal events in DSC experiments. Samples of metallic standard (In, Pb, Sn and Zn) with masses varying from 0.570mg to 20.9mg were analyzed in multiples sample heating rate from 4 to 324°C. min-1. In order to make properly all those experiments, a precise and careful temperature and enthalpy calibrations were performed and deeply discussed. Thus, this work shows a DSC methodology able to generate good and reliable results on experiments under any researcher choice heating rates to characterize the advanced materials used, for example, for aerospace industry. Also it helps the DSC users to find in their available instruments, already installed, a better and more accurate DSC test results, improving in just one shot the analysis sensitivity and resolution. Polypropylene melting and enthalpy thermal events are also studied using both the conventional DSC method and high heating rate method.

Micro-raman spectroscopic characterization of a CR-39 detector

Characterization by micro-Raman spectroscopy of polymeric materials used as nuclear track detectors reveals physico-chemical and morphological information on the material's molecular structure. In this work, the nuclear track detector poly(allyl diglycol carbonate), or Columbia Resin 39 (CR-39), was characterized according to the fluence of alpha particles produced by a 226Ra source and chemical etching time. Therefore, damage of the CR-39 chemical structure due to the alpha-particle interaction with the detector was analyzed at the molecular level. It was observed that the ionization and molecular excitation of the CR-39 after the irradiation process entail cleavage of chemical bonds and formation of latent track. In addition, after the chemical etching, there is also loss of polymer structure, leading to the decrease of the group density C-O-C (∼888 cm-1), CH=CH (∼960 cm -1), C-O (∼1110 cm-1), C-O-C (∼1240 cm -1), C-O (∼1290 cm-1), C-O (∼1741 cm -1), -CH2- (∼2910 cm-1), and the main band -CH2- (∼2950 cm-1). The analyses performed after irradiation and chemical etching led to a better understanding of the CR-39 molecular structure and better comprehension of the process of the formation of the track, which is related to chemical etching kinetics. Copyright © 2013 Society for Applied Spectroscopy.

The igapó of the Negro River in central Amazonia: Linking late-successional inundation forest with fluvial geomorphology

Despite important progress on Amazonian floodplain research, the flooded forest of the Negro River igapó has been little investigated. In particular, no study has previously focused the linkage between fluvial geomorphology and the floristic variation across the course of the river. In this paper we describe and interpret relations between igapó forest, fluvial geomorphology and the spatial evolution of the igapó forest through the Holocene. Therefore, we investigate the effect of geomorphological units of the floodplain and channel patterns on tree diversity, composition and structural parameters of the late-successional igapó forest. Our results show that sites sharing almost identical flooding regime, exhibit variable tree assemblages, species richness and structural parameters such as basal area, tree density and tree heights, indicating a trend in which the geomorphologic styles seem to partially control the organization of igapó's tree communities. This can be also explained by the high variability of well-developed geomorphologic units in short distances and concentrated in small areas. In this dynamic the inputs from the species pool of tributary rivers play a crucial role, but also the depositional and erosional processes associated with the evolution of the floodplain during the Holocene may control floristic and structural components of the igapó forests. These results suggest that a comprehensive approach integrating floristic and geomorphologic methods is needed to understand the distribution of the complex vegetation patterns in complex floodplains such as the igapó of the Negro River. This combination of approaches may introduce a better comprehension of the temporal and spatial evolutionary analysis and a logic rationale to understand the vegetation distribution and variability in function of major landforms, soil distributions and hydrology. Thus, by integrating the past into macroecological analyses will sharpen our understanding of the underlying forces for contemporary floristic patterns along the inundation forests of the Negro River. © 2013 Elsevier Ltd.

Efeito da idade das matrizes de tilápia do nilo Oreochromis niloticus no desenvolvimento embrionário e larval

Pós-graduação em Aquicultura - FCAV

Desenvolvimento do protótipo de um atlas escolar interativo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O cristo no terceiro milênio: a visão plástica da arte sacra atual de Cláudio Pastro

Pós-graduação em Artes - IA

Estudo das variações elétricas em filmes ultrafinos compondo as unidades sensoriais de uma língua eletrônica

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

O Comitê de Bacia e a gestão das águas no médio Paranapanema: um estudo sob a perspectiva do desenvolvimento sustentável

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atividades de campo no ensino das ciências: investigando concepções e práticas de um grupo de professores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Conhecimento básico de genética: concluintes do ensino e graduandos de ciências biológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caminhos para uma prática inclusiva de leitura e escrita na escola

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)