Measurement of the galactic cosmic ray antiproton flux from 0.25 gev to 3.11 gev with the isotope matter antimatter experiment (imax)

The intensities and relative abundances of galactic cosmic ray protons and antiprotons have been measured with the Isotope Matter Antimatter Experiment (IMAX), a balloon-borne magnet spectrometer. The IMAX payload had a successful flight from Lynn Lake, Manitoba, Canada on July 16, 1992. Particles detected by IMAX were identified by mass and charge via the Cherenkov-Rigidity and TOP-Rigidity techniques, with measured rms mass resolution ≤0.2 amu for Z=1 particles.

Cosmic ray antiprotons are of interest because they can be produced by the interactions of high energy protons and heavier nuclei with the interstellar medium as well as by more exotic sources. Previous cosmic ray antiproton experiments have reported an excess of antiprotons over that expected solely from cosmic ray interactions.

Analysis of the flight data has yielded 124405 protons and 3 antiprotons in the energy range 0.19-0.97 GeV at the instrument, 140617 protons and 8 antiprotons in the energy range 0.97-2.58 GeV, and 22524 protons and 5 antiprotons in the energy range 2.58-3.08 GeV. These measurements are a statistical improvement over previous antiproton measurements, and they demonstrate improved separation of antiprotons from the more abundant fluxes of protons, electrons, and other cosmic ray species.

When these results are corrected for instrumental and atmospheric background and losses, the ratios at the top of the atmosphere are p/p=3.21(+3.49, -1.97)x10^(-5) in the energy range 0.25-1.00 GeV, p/p=5.38(+3.48, -2.45) x10^(-5) in the energy range 1.00-2.61 GeV, and p/p=2.05(+1.79, -1.15) x10^(-4) in the energy range 2.61-3.11 GeV. The corresponding antiproton intensities, also corrected to the top of the atmosphere, are 2.3(+2.5, -1.4) x10^(-2) (m^2 s sr GeV)^(-1), 2.1(+1.4, -1.0) x10^(-2) (m^2 s sr GeV)^(-1), and 4.3(+3.7, -2.4) x10^(-2) (m^2 s sr GeV)^(-1) for the same energy ranges.

The IMAX antiproton fluxes and antiproton/proton ratios are compared with recent Standard Leaky Box Model (SLBM) calculations of the cosmic ray antiproton abundance. According to this model, cosmic ray antiprotons are secondary cosmic rays arising solely from the interaction of high energy cosmic rays with the interstellar medium. The effects of solar modulation of protons and antiprotons are also calculated, showing that the antiproton/proton ratio can vary by as much as an order of magnitude over the solar cycle. When solar modulation is taken into account, the IMAX antiproton measurements are found to be consistent with the most recent calculations of the SLBM. No evidence is found in the IMAX data for excess antiprotons arising from the decay of galactic dark matter, which had been suggested as an interpretation of earlier measurements. Furthermore, the consistency of the current results with the SLBM calculations suggests that the mean antiproton lifetime is at least as large as the cosmic ray storage time in the galaxy (~10^7 yr, based on measurements of cosmic ray ^(10)Be). Recent measurements by two other experiments are consistent with this interpretation of the IMAX antiproton results.

A balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen

The isotopic compositions of galactic cosmic ray boron, carbon, and nitrogen have been measured at energies near 300 MeV amu^-1, using a balloon-borne instrument at an atmospheric depth of ~5 g cm^-2. The calibrations of the detectors comprising the instrument are described. The saturation properties of the cesium iodide scintilla tors used for measurement of particle energy are studied in the context of analyzing the data for mass. The achieved rms mass resolution varies from ~ 0.3 amu at boron to ~ 0.5 amu at nitrogen, consistent with a theoretical analysis of the contributing factors. Corrected for detector interactions and the effects of the residual atmosphere, the results are ^(10)B/B = 0.33^(+0.17)_(-0.11), ^(13)C/C = 0.06^(+0.13)_(-0.01), and ^(15)N/N = 0.42 (+0.19)_(-0.17). A model of galactic propagation and solar modulation is described. Assuming a cosmic ray source composition of solar-like isotopic abundances, the model predicts abundances near earth consistent with the measurements.

First principles based multiparadigm modeling of electronic structures and dynamics

Electronic structures and dynamics are the key to linking the material composition and structure to functionality and performance.

An essential issue in developing semiconductor devices for photovoltaics is to design materials with optimal band gaps and relative positioning of band levels. Approximate DFT methods have been justified to predict band gaps from KS/GKS eigenvalues, but the accuracy is decisively dependent on the choice of XC functionals. We show here for CuInSe₂ and CuGaSe₂, the parent compounds of the promising CIGS solar cells, conventional LDA and GGA obtain gaps of 0.0-0.01 and 0.02-0.24 eV (versus experimental values of 1.04 and 1.67 eV), while the historically first global hybrid functional, B3PW91, is surprisingly the best, with band gaps of 1.07 and 1.58 eV. Furthermore, we show that for 27 related binary and ternary semiconductors, B3PW91 predicts gaps with a MAD of only 0.09 eV, which is substantially better than all modern hybrid functionals, including B3LYP (MAD of 0.19 eV) and screened hybrid functional HSE06 (MAD of 0.18 eV).

The laboratory performance of CIGS solar cells (> 20% efficiency) makes them promising candidate photovoltaic devices. However, there remains little understanding of how defects at the CIGS/CdS interface affect the band offsets and interfacial energies, and hence the performance of manufactured devices. To determine these relationships, we use the B3PW91 hybrid functional of DFT with the AEP method that we validate to provide very accurate descriptions of both band gaps and band offsets. This confirms the weak dependence of band offsets on surface orientation observed experimentally. We predict that the CBO of perfect CuInSe₂/CdS interface is large, 0.79 eV, which would dramatically degrade performance. Moreover we show that band gap widening induced by Ga adjusts only the VBO, and we find that Cd impurities do not significantly affect the CBO. Thus we show that Cu vacancies at the interface play the key role in enabling the tunability of CBO. We predict that Na further improves the CBO through electrostatically elevating the valence levels to decrease the CBO, explaining the observed essential role of Na for high performance. Moreover we find that K leads to a dramatic decrease in the CBO to 0.05 eV, much better than Na. We suggest that the efficiency of CIGS devices might be improved substantially by tuning the ratio of Na to K, with the improved phase stability of Na balancing phase instability from K. All these defects reduce interfacial stability slightly, but not significantly.

A number of exotic structures have been formed through high pressure chemistry, but applications have been hindered by difficulties in recovering the high pressure phase to ambient conditions (i.e., one atmosphere and room temperature). Here we use dispersion-corrected DFT (PBE-ulg flavor) to predict that above 60 GPa the most stable form of N₂O (the laughing gas in its molecular form) is a 1D polymer with an all-nitrogen backbone analogous to cis-polyacetylene in which alternate N are bonded (ionic covalent) to O. The analogous trans-polymer is only 0.03-0.10 eV/molecular unit less stable. Upon relaxation to ambient conditions both polymers relax below 14 GPa to the same stable non-planar trans-polymer, accompanied by possible electronic structure transitions. The predicted phonon spectrum and dissociation kinetics validate the stability of this trans-poly-NNO at ambient conditions, which has potential applications as a new type of conducting polymer with all-nitrogen chains and as a high-energy oxidizer for rocket propulsion. This work illustrates in silico materials discovery particularly in the realm of extreme conditions.

Modeling non-adiabatic electron dynamics has been a long-standing challenge for computational chemistry and materials science, and the eFF method presents a cost-efficient alternative. However, due to the deficiency of FSG representation, eFF is limited to low-Z elements with electrons of predominant s-character. To overcome this, we introduce a formal set of ECP extensions that enable accurate description of p-block elements. The extensions consist of a model representing the core electrons with the nucleus as a single pseudo particle represented by FSG, interacting with valence electrons through ECPs. We demonstrate and validate the ECP extensions for complex bonding structures, geometries, and energetics of systems with p-block character (C, O, Al, Si) and apply them to study materials under extreme mechanical loading conditions.

Despite its success, the eFF framework has some limitations, originated from both the design of Pauli potentials and the FSG representation. To overcome these, we develop a new framework of two-level hierarchy that is a more rigorous and accurate successor to the eFF method. The fundamental level, GHA-QM, is based on a new set of Pauli potentials that renders exact QM level of accuracy for any FSG represented electron systems. To achieve this, we start with using exactly derived energy expressions for the same spin electron pair, and fitting a simple functional form, inspired by DFT, against open singlet electron pair curves (H₂ systems). Symmetric and asymmetric scaling factors are then introduced at this level to recover the QM total energies of multiple electron pair systems from the sum of local interactions. To complement the imperfect FSG representation, the AMPERE extension is implemented, and aims at embedding the interactions associated with both the cusp condition and explicit nodal structures. The whole GHA-QM+AMPERE framework is tested on H element, and the preliminary results are promising.

Validação do processo de limpeza de tanque multiuso utilizado para formulação de vacinas

A validação de limpeza de equipamentos é requisito regulatório para assegurar que os procedimentos de limpeza removem os resíduos de produto e agente de limpeza existentes até um nível de aceitação pré-determinado, garantindo que não haja contaminação cruzada. A metodologia analítica escolhida para monitorar a ocorrência de contaminação cruzada foi a determinação de carbono orgânico total (TOC) por ser uma técnica não específica permitindo assim quantificar os resíduos antes e após o procedimento de limpeza. Para execução desta validação foi selecionado o pior caso em relação ao contaminante. A vacina Hib foi escolhida como pior caso, pois possui maior aderência ao aço inox 316L, apresentando uma menor percentagem de recuperação, quando comparada à vacina Meningite A e C, sendo respectivamente de 93,0% e 98,4% para o tempo de extração de 30 segundos e 67,8% e 72,6% para o tempo de extração de 10 segundos. O resíduo aceitável de produto em água de rinsagem foi de 0,0007 g/mL de polissacarídeo (0,49 g/mL de TOC) e em swab foi de 0,006 g/mL de polissacarídeo (3,49 g/mL de TOC). As amostras retiradas para determinação de resíduo de produto foram analisadas e corrigidas pelo fator de recuperação deste resíduo para amostras de água de rinsagem que é de 98,5% e para amostras em swab que é de 98,4%. Já o resíduo aceitável para agente de limpeza (NaOH) foi de 3,5 g/mL que fornece um pH de 9,94, porém não existem evidências que a concentração calculada de resíduo de NaOH não interferirá quimicamente ao entrar em contato com a vacina. Assim o critério adotado foi o mesmo da água para injetáveis, segundo USP que é pH entre 5 e 7. As amostras retiradas para determinação de resíduo de agente de limpeza não foram corrigidas pelo fator de recuperação uma vez que o critério utilizado é muito mais crítico que o calculado. Todas as análises realizadas apresentaram resultados dentro dos parâmetros aceitáveis permitindo a conclusão de que o procedimento de limpeza para tanque de aço inox 316L é eficiente removendo os resíduos até níveis aceitáveis, evitando assim uma contaminação cruzada

Estimating Sighting Proportions of American Alligator Nests during Helicopter Survey

Proportions of American alligator (Alligator mississippiensis) nests sighted during aerial survey in Florida were estimated based upon multiple surveys by different observers. We compared sighting proportions across habitats, nesting seasons, and observer experience levels. The mean sighting proportion across all habitats and years was 0.736 (SE=0.024). Survey counts corrected by the mean sighting proportion reliably predicted total nest counts (R2=0.933). Sighting proportions did not differ by habitat type (P=0.668) or year P=0.328). Experienced observers detected a greater proportion of nests (Pcorrected by the appropriate sighting proportion.

Studies of noble gases in meteorites and in the earth

The isotopic and elemental abundances of noble gases in the solar system are investigated, using simple mixing models and mass-spectrometric measurements of the noble gases in meteorites and terrestrial rocks and minerals.

Primordial neon is modeled by two isotopically distinct components from the interstellar gas and dust. Neon from the gas dominates solar neon, which contains about ten times more ²⁰Ne than ²²Ne. Neon from the dust is represented in meteorites by neon-E, with ²⁰Ne/²²Ne less than 0.6. Isotopic variations in meteorites require neon from both dust and gas to be present. Mixing dust and gas without neon loss generates linear correlation lines on three-isotope and composition-concentration diagrams. A model for solar wind implantation predicts small deviations from linear mixing, due to preferential sputtering of the lighter neon isotopes.

Neon in meteorites consists of galactic cosmic ray spallation neon and at least two primordial components, neon-E and neon-S. Neon was measured in several meteorites to investigate these end- members. Cosmogenic neon produced from sodium is found to be strongly enriched in ²²Ne. Neon measurements on sodium-rich samples must be interpreted with care so not to confuse this source of ²²Ne with neon-E, which is also rich in ²²Ne.

Neon data for the carbonaceous chondrite Mokoia show that the end member composition of neon-Si in meteorites is ²⁰Ne/²²Ne = 13.7, the same as the present solar wind. The solar wind composition evidently has remained constant since before the compaction of Mokoia.

Ca, Al-rich inclusions from the Allende meteorite were examined for correlation between neon-E and oxygen or magnesium isotopic anomalies. ²²Ne and ³⁶Ar enrichments found in some inclusions are attributed to cosmic- ray-induced reactions on Na and Cl, not to a primordial component. Neon-E is not detectably enriched in Allende.

Measurements were made to determine the noble gas contents of various terrestrial rocks and minerals, and to investigate the cycling of noble gases between different terrestrial reservoirs. Beryl crystals contain a characteristic suite of magmatic gases including nucleogenic ²¹Ne and ²²Ne from (α,n) reactions, radiogenic ⁴⁰Ar, and fissiogenic ^131-136Xe from the decay of K and U in the continental crust. Significant concentrations of atmospheric noble gases are also present in beryl.

Both juvenile and atmospheric noble gases are found in rocks from the Skaergaard intrusion. The ratio ⁴⁰Ar/³⁶Ar (corrected for in situ decay of ⁴⁰K) correlates with δ¹⁸O in plagioclase. Atmospheric argon has been introduced into samples that have experienced oxygen-isotope exchange with circulating meteoric hydrothermal fluids. Unexchanged samples contain juvenile argon with ⁴⁰Ar/³⁶Ar greater than 6000 that was trapped from the Skaergaard magma.

Juvenile and atmospheric gases have been measured in the glassy rims of mid-ocean ridge (MOR) pillow basalts. Evidence is presented that three samples contain excess radiogenic ¹²⁹Xe and fission xenon, in addition to the excess radiogenic ⁴⁰Ar found in all samples. These juvenile gases are being outgassed from the upper-mantle source region of the MOR magma. No isotopic evidence has been found here for juvenile primordial noble gases accompanying the juvenile radiogenic gases in the MOR glasses. Large argon isotopic variations in a single specimen provide a clear indication of the late-stage addition of atmospheric argon, probably from seawater.

The Skaergaard data demonstrate that atmospheric noble gases dissolved in ground water can be transferred into crustal rocks. Subduction of oceanic crust altered by seawater can transport atmospheric noble gases into the upper mantle. A substantial portion of the noble gases in mantle derived rocks may represent subducted gases, not a primordial component as is often assumed.

1. Ultrasonic studies of binary liquid structure in the critical region. Theory and experiment for the 2,6-lutidine/water system. 2. Hartree-Fock calculations of electric polarizabilities of some simple atoms and molecules, and their practicality. 3. Calculation of vibrational transition probabilities in collinear atom-diatom and diatom-diatom collisions with Lennard-Jones interaction

Part 1. Many interesting visual and mechanical phenomena occur in the critical region of fluids, both for the gas-liquid and liquid-liquid transitions. The precise thermodynamic and transport behavior here has some broad consequences for the molecular theory of liquids. Previous studies in this laboratory on a liquid-liquid critical mixture via ultrasonics supported a basically classical analysis of fluid behavior by M. Fixman (e. g., the free energy is assumed analytic in intensive variables in the thermodynamics)--at least when the fluid is not too close to critical. A breakdown in classical concepts is evidenced close to critical, in some well-defined ways. We have studied herein a liquid-liquid critical system of complementary nature (possessing a lower critical mixing or consolute temperature) to all previous mixtures, to look for new qualitative critical behavior. We did not find such new behavior in the ultrasonic absorption ascribable to the critical fluctuations, but we did find extra absorption due to chemical processes (yet these are related to the mixing behavior generating the lower consolute point). We rederived, corrected, and extended Fixman's analysis to interpret our experimental results in these more complex circumstances. The entire account of theory and experiment is prefaced by an extensive introduction recounting the general status of liquid state theory. The introduction provides a context for our present work, and also points out problems deserving attention. Interest in these problems was stimulated by this work but also by work in Part 3.

Part 2. Among variational theories of electronic structure, the Hartree-Fock theory has proved particularly valuable for a practical understanding of such properties as chemical binding, electric multipole moments, and X-ray scattering intensity. It also provides the most tractable method of calculating first-order properties under external or internal one-electron perturbations, either developed explicitly in orders of perturbation theory or in the fully self-consistent method. The accuracy and consistency of first-order properties are poorer than those of zero-order properties, but this is most often due to the use of explicit approximations in solving the perturbed equations, or to inadequacy of the variational basis in size or composition. We have calculated the electric polarizabilities of H₂, He, Li, Be, LiH, and N₂ by Hartree-Fock theory, using exact perturbation theory or the fully self-consistent method, as dictated by convenience. By careful studies on total basis set composition, we obtained good approximations to limiting Hartree-Fock values of polarizabilities with bases of reasonable size. The values for all species, and for each direction in the molecular cases, are within 8% of experiment, or of best theoretical values in the absence of the former. Our results support the use of unadorned Hartree-Pock theory for static polarizabilities needed in interpreting electron-molecule scattering data, collision-induced light scattering experiments, and other phenomena involving experimentally inaccessible polarizabilities.

Part 3. Numerical integration of the close-coupled scattering equations has been carried out to obtain vibrational transition probabilities for some models of the electronically adiabatic H₂-H₂ collision. All the models use a Lennard-Jones interaction potential between nearest atoms in the collision partners. We have analyzed the results for some insight into the vibrational excitation process in its dependence on the energy of collision, the nature of the vibrational binding potential, and other factors. We conclude also that replacement of earlier, simpler models of the interaction potential by the Lennard-Jones form adds very little realism for all the complication it introduces. A brief introduction precedes the presentation of our work and places it in the context of attempts to understand the collisional activation process in chemical reactions as well as some other chemical dynamics.

Computational Microscopy: Breaking the Limit of Conventional Optics

Computational imaging is flourishing thanks to the recent advancement in array photodetectors and image processing algorithms. This thesis presents Fourier ptychography, which is a computational imaging technique implemented in microscopy to break the limit of conventional optics. With the implementation of Fourier ptychography, the resolution of the imaging system can surpass the diffraction limit of the objective lens's numerical aperture; the quantitative phase information of a sample can be reconstructed from intensity-only measurements; and the aberration of a microscope system can be characterized and computationally corrected. This computational microscopy technique enhances the performance of conventional optical systems and expands the scope of their applications.

The structure of liquid argon as determined by x-ray diffraction

X-ray diffraction measurements and subsequent data analyses have been carried out on liquid argon at five states in the density range of 0.91 to 1.135 gm/cc and temperature range of 127 to 143°K. Duplicate measurements were made on all states. These data yielded radial distribution and direct correlation functions which were then used to compute the pair potential using the Percus-Yevick equation. The potential minima are in the range of -105 to -120°K and appear to substantiate current theoretical estimates of the effective pair potential in the presence of a weak three-body force.

The data analysis procedure used was new and does not distinguish between the coherent and incoherent absorption factors for the cell scattering which were essentially equal. With this simplification, the argon scattering estimate was compared to the gas scattering estimate on the laboratory frame of reference and the two estimates coincided, indicating the data normalized. The argon scattering on the laboratory frame of reference was examined for the existence of the peaks in the structure factor and the existence of an observable third peak was considered doubtful.

Numerical studies of the effect of truncation, normalization, the subsidiary peak phenomenon in the radial distribution function, uncertainties in the low angle data relative to errors in the direct correlation function and the distortion phenomenon are presented.

The distortion phenomenon for this experiment explains why the Mikolaj-Pings argon data yielded pair potential well depths from the Percus-Yevick equation that were too shallow and an apparent slope with respect to density that was too steep compared to theoretical estimates.

The data presented for each measurement are: empty cell and cell plus argon intensity, absorption factors, argon intensity, smoothed argon intensity, smoothed argon intensity corrected for distortion, structure factor, radial distribution function, direct correlation function and the pair potential from the Percus-Yevick equation.

Digital holographic aberration compensation in electron holography

This paper proposes a new digital method to compensate for the aberration of an electron objective lens in electron holography. In this method, the object wavefront in the exit pupil plane is numerically reconstructed from a digitized electron hologram, and is corrected by multiplying it with the conjugated phase-error function. Then, an aberration-free image can be obtained by calculating the Fresnel integral of this corrected wavefront. In comparison with traditional methods, this method is much more convenient and accurate. Some verifying experiments are also presented in this paper. (C) 2003 Society of Photo-optical Instrumentation Engineers.

Parâmetros de avaliação nutricional para detectar desnutrição em pacientes com AIDS em tratamento com antirretrovirais

A avaliação do estado nutricional em pacientes com HIV é de grande importância, pois as conseqüências provocadas pelo processo patológico da doença estão associadas com perda de peso corporal, massa magra e desnutrição grave, o que prediz aumento da morbimortalidade. Os valores de linfometria CD4 também têm sido utilizados como preditores a curto e médio prazo para o desenvolvimento de infecções oportunistas, as quais são incomuns em pacientes com CD4 >200 cels/mm3. Partindo deste conhecimento, optou-se por estudar o estado nutricional de homens e mulheres HIV positivos de acordo com a contagem de células CD4. Utilizou-se como parâmetros nutricionais o índice de massa corporal (IMC), a área muscular do braço corrigida (AMBc), albumina sérica e o ângulo de fase (AF). Foram estudados 39 pacientes HIV positivos, acompanhados pelo ambulatório de doenças infectoparasitárias do Hospital Universitário Pedro Ernesto (HUPE/UERJ). Não foi observada desnutrição na população estudada, quando avaliada pelo IMC e albumina em ambos os sexos, independente do número de células CD4. Entretanto, a AMBc e o AF, tanto nos homens quanto nas mulheres, demonstraram comprometimento nos parâmetros de massa magra. Em relação à associação entre os indicadores nutricionais e o número de células CD4, foi observado correlação significante com a AMBc e a albumina no grupo estudado. A correlação de acordo com o sexo manteve-se significante em ambos os grupos para AMBc e com uma tendência positiva (p=0,06) entre o AF e CD4 no grupo dos homens. Portanto, estes resultados demonstram que para avaliar o estado nutricional, principalmente o compartimento de massa corporal magra de pacientes HIV positivos sob terapia antirretroviral, é preciso utilizar indicadores mais sensíveis, mesmo naqueles pacientes com melhor estado de controle da doença.

Reavaliação deposicional da Bacia de São José de Itaboraí com base em dados geológicos e geofísicos

A Bacia de São José de Itaboraí está localizada no Município de Itaboraí, no Estado do Rio de Janeiro. Ela foi descoberta em 1928, pelo Engenheiro Carlos Euler, que após analisar um suposto caulim encontrado na Fazenda São José pelo seu então proprietário, Sr. Ernesto Coube, verificou que se tratava de calcário. Os Professores Rui Lima e Silva e Othon H. Leonardos, enviados ao local para estudos, encontraram uma grande quantidade de fósseis de gastrópodes continentais, despertando o interesse científico pela região. Os estudos preliminares de campo e análises químicas evidenciaram boas perspectivas de exploração do calcário para a fabricação de cimento do tipo Portland. Por mais de 50 anos, a Companhia Nacional de Cimento Portland Mauá (CNCPM) explorou a pedreira. Desde sua descoberta, a Bacia de São José, paralelamente às atividades de mineração, foi objeto de pesquisas científicas realizadas por geólogos, paleontólogos e arqueólogos. No início da década de 80, a Cia. de Cimento Mauá decidiu abandonar a área em função do esgotamento econômico da reserva de minério. Com a retirada das bombas que impediam a inundação da pedreira, formou-se uma lagoa que passou a impedir o livre acesso aos afloramentos. Desde então as pesquisas sobre a Bacia ficaram concentradas aos materiais coletados no período de exploração de calcário. Material esse distribuído no Museu Nacional (MN), Departamento Nacional da Produção Mineral (DNPM), Instituto de Geociências da UFRJ, entre outros. Em 1990, a área que pertencia a CNCPM foi desapropriada por pressão da comunidade científica. A mesma passou a pertencer ao Município de Itaboraí, que criou o Parque Paleontológico de São José de Itaboraí, por meio da Lei 1.346, de 12 de dezembro de 1995. O objetivo desse trabalho foi gerar novos dados através do método geofísico conhecido como magnetometria. Para isso foram realizados levantamentos de campo utilizando um magnetômetro portátil e GPS, foram analisados e corrigidos dados utilizando softwares específicos, elaborados modelos e criados perfis a partir de descrições de testemunhos de sondagem. Os resultados obtidos visam possibilitar uma nova interpretação da geologia e da estratigrafia da bacia, dando condições para que se possa ter uma atualização dos conhecimentos relacionados à região, após quase meio século de atividade mineradora.

Efeitos da suplementação dietética com cálcio sobre a plasticidade ontogenética decorrente do desmame precoce ou da exposição materna a nicotina na lactação

O cálcio tem se mostrado útil na regulação do metabolismo energético, favorecendo a perda de peso. Visto que tanto o desmame precoce como a exposição materna à nicotina na lactação são fatores condicionantes para o desenvolvimento de obesidade, hiperleptinemia e resistência à insulina, além de outras alterações endócrinas na idade adulta, decidimos avaliar os possíveis efeitos da suplementação dietética com cálcio sobre as disfunções apresentadas pelos seguintes modelos experimentais: 1) Desmame precoce (DP): ratas lactantes foram envolvidas com atadura para interromper o acesso da prole ao leite nos 3 últimos dias da lactação. As proles das ratas controles tiveram livre acesso ao leite materno durante todo o período da lactação (21 dias). 2) Exposição materna à nicotina (N): Dois dias após o nascimento, ratas lactantes receberam implantes de minibombas osmóticas contendo solução de nicotina (6 mg/kg/dia, 14 dias) ou salina (C), nas mesmas condições. Aos 120 dias de idade, as proles de ambos os modelos de obesidade experimental receberam dieta padrão ou dieta suplementada com cálcio (10g de carbonato de cálcio/kg de ração). O sacrifício ocorreu aos 180 dias de idade. Os dados foram considerados significativos quando p<0,05. Corroborando dados anteriores do nosso grupo, as proles de ambos os modelos de programação (N e DP) apresentaram maior gordura corporal total e visceral, hiperleptinemia, resistência hipotalâmica a leptina e distúrbios na homeostase glicêmica. Além disto, verificamos que as proles N e DP também exibiram aumento dos níveis séricos de 25-hidroxivitamina D3. Todos essas alterações endócrino-metabólicas foram corrigidas pelo tratamento com suplementação com cálcio. Além disso, a prole DP aos 180 dias mostrou hiperfagia e hipertrigliceridemia, que também foram normalizados pela suplementação dietética com cálcio. A prole N apresentou hipotireoidismo, maior conteúdo de catecolaminas e maior expressão de tirosina hidroxilase (TH). A terapia com cálcio reverteu a disfunção adrenal, embora não tenha sido eficaz para normalizar a hipofunção tireoideana. Assim, a suplementação dietética com cálcio normalizou a maioria dos parâmetros da síndrome metabólica observadas nos dois modelos de plasticidade ontogenética. É possível que a redução da adiposidade central induzida pela terapia com cálcio, por si, tenha sido o principal mecanismo que resultou na melhora dos parâmetros estudados. Uma vez que a suplentação de cálcio reverteu as concentrações séricas de 25-hidroxivitamina D3 dos animais obesos, é possível que o efeito anti-obesidade do cálcio também ocorra via ação do calcitriol sobre o adipócito.

新型板条激光器的离轴混合腔模场计算

报道了一种新型双板条离轴混合腔激光器。这种激光器结构通过改变传统的冷却方式和采用特殊的谐振腔设计，将使从第一块介质板条高温一侧出射的激光对称地进入另一块板条的低温一侧，从而可对由于温度分布不均匀造成的波面畸变进行一定程度的自校正，减少热效应的影响，可望提高激光器的输出功率和光束质量。利用快速傅里叶变换（FFT）对这种激光器的近场、远场以及相位等模场特性进行了数值计算。分析了波面畸变对输出光束质量的影响，并与常规双板条激光器进行了比较，结果表明这种新型双板条离轴混合腔激光器可以实现一定程度的波面畸变自补偿，

Fenofibrato (agonista do receptor ativador da proliferação peroxissomal) modula o sistema renina-angiotensina no coração de camundongos alimentados com dieta hiperlipídica

O objetivo deste trabalho foi estudar a ação do fenofibrato, um agonista do receptor ativador da proliferação peroxissomal alfa, no remodelamento cardíaco e na expressão de componentes do sistema renina-angiotensina (SRA) em um modelo de obesidade induzida por dieta. Camundongos machos C57Bl/6 com três meses de idade foram alimentados durante 11 semanas com dieta controle (grupo C, 3,57 kcal/g de dieta) ou dieta hiperlipídica (grupo HL, 5,40 kcal/g de dieta), em seguida foram separados em quatro grupos e estudados durante cinco semanas: C; HL; C-L (C mais fenofibrato) e HL-F (HL mais fenofibrato). Os animais HL foram mais pesados e apresentaram maior pressão arterial (PA) comparados aos animais C, mas HL-F foram mais leves e tiveram PA menor que HL. A resistência insulínica vista nos camundongos HL foi melhorada com fenofibrato nos camundongos HL-F. Fenofibrato reduziu colesterol total, triglicerídeos e aumentou HDL-c. Os animais HL apresentou um ventrículo esquerdo (VE) mais pesado e com espessura da parede maior, como também cardiomiócitos maiores e uma menor razão cardiomiócito/capilares que os animais C. Fenofibrato foi eficiente em melhorar estas alterações. As expressões cardíacas de Angiotensina II (ANG II) e de seu receptor tipo 1 (AT1R) foram maiores, enquanto que a expressão de seu receptor tipo 2 (AT2R) foi menor nos animais HL que nos animais C, e fenofibrato foi eficiente em atenuar estas diferenças. Como conclusão, a dieta HL lidera para a obesidade, elevação da PA, hipertrofia cardíaca, alterações metabólicas e expressão proteica alterada do SRA em camundongos, sugerindo a participação do SRA nestas alterações. Fenofibrato é eficiente em diminuir a PA e controlar a expressão proteica do SRA, assim como no tratamento da resistência insulínica e do remodelamento cardíaco adverso, diminuindo a hipertrofia dos cardiomiócitos e melhorando a vascularização do miocárdio, desta maneira, diminuindo importantes fatores de risco para doenças cardiovasculares