The quest for an intermediate-scale accidental axion and further ALPs

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

Notes on the feeding behaviour and swimming pattern of Manta alfredi (Chondrichthyes, Mobulidae) in the Red Sea

The feeding behaviour and the swimming pattern of the reef manta (Manta alfredi) are described based on video recordings conducted in Sudan, Red Sea, Indian Ocean, during June 2001. Three circular swimming patterns are described: horizontal circle pattern, inclined circle pattern and double circle pattern, related to feedings on zooplankton distributed in the water column. The observation of circle-like swimming patterns for reef manta rays in shallow waters expands our knowledge about M. alfredi and suggests that the distribution and abundance of zooplankton influence the occurrence and group size of this species in the studied area, as reported from other localities for Manta species.

Datação de Cerâmicas Arqueológicas do Noroeste Paulista pelo Método da Termoluminescência

Pós-graduação em Ciência dos Materiais - FEIS

Aplicação de cavacos de titânio para produção de revestimentos resistentes ao desgaste

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

New species of Cyphocharax (Characiformes: Curimatidae) from the upper rio Negro, Amazon basin

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

Redescription of Moenkhausia doceana (Steindachner, 1877) (Ostariophysi: Characiformes): a characid from the Northeastern Mata Atlântica ecoregion, Brazil

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

Comparative wood anatomy of root and stem of Citharexylum myrianthum (Verbenaceae)

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

Propriedades estruturais e espectroscópicas de complexos de difenilfosfinatos dos sistemas ternários 'LA'-'CE'-'EU'/'LA'-CE'-'TB'

Pós-graduação em Química - IQ

Effect of Zn2+ ions on the structure, morphology and optical properties of CaWO4 microcrystals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hard X-ray photoemission study of the Fabre salts (TMTTF)(2)X (X = SbF6 and PF6)

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

Neoplecostomus doceensis: a new loricariid species (Teleostei, Siluriformes) from the rio Doce basin and comments about its putative origin

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

Ótica e a visão humana

Optics consists in the study of interaction of light with physical systems. The human vision is a product of the interaction of light with the eye (a very peculiar physical system). Here we present a basic study of the relationship between the optics and human vision, including: - The fundaments and physicals properties who characterize the light and the colors and the characteristics of the incidence mediums. - The basics laws of geometrical optics, based in the rectilinear propagation of light in the form of a light ray, in the independence of light rays and in the principle of reversibility of the light beams. This principle is present in the process of image formations in lenses and mirrors and applied in the study of image formation in the human eye. - The refraction and reflection laws and types of lenses, who permits the construction of optics devices for the study of physical universe, and the appliances to correct vision diseases. - Presents the human vision process as consisting in the reception of light (electromagnetic radiation in the zone of wavelength visible to us) through the eye and the sending of information obtained by the retina to the brain where it is interpreted. The vision involves a biophysical relation between the light and the biological structure of the eye who is constituted by cornea, iris, crystalline and retina. Analyzes is made of how some parts of the eye performs a function in the reception and sending of information of the images to the brain

Indução de morte celular por apoptose decorrente da irradiação com Raios-X: um ensaio com células mamárias humanas tumorais

Apoptosis is a form of programmed cell death selectively removes abnormal cells, and thus contributes to maintaining the balance of the dynamics of cell reproduction. Therefore the verification of the occurrence of apoptotic cell death after a pathological stimulus is crucial for the analysis of the maintenance of normal cell cycle of a given tissue or organ. In this experiment were used cells lines human mammary tumor MDAMB231, T47, MCF7, which were irradiated with X-rays at a dose of 5 Gy in a time interval of 15 seconds, and filtration of 1mm aluminum. Samples containing the cells were grown in a specific culture medium, containing fetal bovine serum and growth factor, and two samples were prepared with each of the cell lines, one to be irradiated, and another that has not been irradiated, which denoted by negative control of the irradiation. The primary goal of the experiment was to verify and compare the rates of apoptosis in each cell lines, in which were irradiated and that were not irradiated, using flow cytometry as a method for detecting apoptotic cell death in together with specific markers annexin V and propidium iodide. Data from the readings made by flow cytometry were analyzed and interpreted using the software WinMDI statistical graph. By comparing the indices relating to the readings of positive and negative for specific markers of apoptosis, based on differences in the statistical data presented lectures regarding the cellular irradiated and not irradiated, collude cells in question once... (Complete abstract click electronic access below)

Aplicações clássicas da técnica de espalhamento de raios-x a baixo ângulo em materiais nanoestruturados

The small angle X-ray scattering (SAXS) technique has been used with very much versatility and success in the structural characterization of nanostructured materials. The present work deals with a study of the principles of the SAXS technique and of some classical models employed in the structural characterization of nanostructured materials. Particularly, the study of the models and of the associated methodologies is applied to a set of samples of silica gels, of varied typical structures, prepared in the Laboratório de Novos Materiais of the Departamento de Física of the IGCE. The work discusses in an introductory chapter the principles of the SAXS technique and the foundation of classical models often used in the structural characterization of materials. The classical models and the associated methodologies were applied to a variety of silica gel structures. The studies include: i) the scattering from a system of particles - Guinier's law; ii) the asymptotic scattering from a two-phase system - Porod's law; iii) systematic deviation from Porod's law - Surface Fractal; iv) heterogeneities in solids with random size distribution - DAB Model; and v) the scattering from mass fractal structures. The analyses were carried out from experimental SAXS data obtained in several opportunities at the Laboratório Nacional de Luz Síncrotron (LNLS)

Uso do método de Monte Carlo para simulação e detecção do espectro de raios-X gerado com feixes de elétrons em alvo de Molibdênio, utilizando o Geant4

The huge demand for procedures involving ionizing radiation promotes the need for safe methods of experimentation considering the danger of their biological e ects with consequent risk to humans. Brazilian's legislation prohibits experiments involving this type of radiation in humans through Decree 453 of Ministry of Health with determines that such procedures comply with the principles of justi cation, optimization and dose limitation. In this line, concurrently with the advancement of available computer processing power, computing simulations have become relevant in those situations where experimental procedures are too cost or impractical. The Monte Carlo method, created along the Manhattan Project duringWorldWar II, is a powerful strategy to simulations in computational physics. In medical physics, this technique has been extensively used with applications in diagnostics and cancer treatment. The objective of this work is to simulate the production and detection of X-rays for the energy range of diagnostic radiology, for molybdenum target, using the Geant4 toolkit. X-ray tubes with this kind of target material are used in diagnostic radiology, speci cally in mammography, one of the most used techniques for screening of breast cancer in women. During the simulations, we used di erent models for bremsstrahlung available in physical models for low energy, in situations already covered by the literature in earlier versions of Geant4. Our results show that although the physical situations seems qualitatively adequate, quantitative comparisons to available analytical data shows aws in the code of Geant4 Low Energy source