Photo induced ionization dynamics of the nitrogen vacancy defect in diamond investigated by single shot charge state detection

The nitrogen-vacancy centre (NV) has drawn much attention for over a decade, yet detailed knowledge of the photophysics needs to be established. Under typical conditions, the NV can have two stable charge states, negative (NV-) or neutral (NV0), with photo induced interconversion of these two states. Here, we present detailed studies of the ionization dynamics of single NV centres in bulk diamond at room temperature during illumination in dependence of the excitation wavelength and power. We apply a recent method which allows us to directly measure the charge state of a single NV centre, and observe its temporal evolution. Results of this work are the steady state NV- population, which was found to be always < 75% for 450 to 610 nm excitation wavelength, the relative absorption cross-section of NV- for 540 to 610 nm, and the energy of the NV- ground state of 2.6 eV below the conduction band. These results will help to further understand the photo-physics of the NV centre.Comment: 9 pages, 7 figure

Uso de sêmen resfriado e inseminação artificial em caprinos leiteiros na República de Cabo Verde.

Resumo: Resumo: Este projeto e fruto de um trabalho conjunto entre a Agencia Brasileira de Cooperacao Internacional, CNPq, Embrapa, Governo de Cabo Verde, GOPA, UFF e UFPR. Teve como objetivo treinar tecnicos caboverdianos, para que possam executar todas as etapas envolvidas em um programa de inseminacao artificial (IA); determinar um protocolo de IA com semen resfriado que possibilite a disseminacao de genetica para todas as ilhas do arquipelago; fazer uma primeira disseminacao genetica; estruturar um centro de coleta e manipulacao de semen caprino; alem de avaliar a viabilidade da utilizacao do semen caprino diluido em meio tris-gema 2,5% (Evans & Maxwell, 1987; modificado), resfriado a 5 ‹C e armazenado por diferentes periodos (24 ou 48 horas). Foram inseminadas por via transcervical 133 cabras sem raca definida e nativas da Republica de Cabo Verde, divididas aleatoriamente em dois tratamentos T24 e T48. O estro foi sincronizado com a utilizacao de esponjas intra-vaginais contendo 60 mg de acetato de medroxiprogesterona por seis dias; 37,5 ƒÊg de D-cloprostenol e 200 UI de eCG 24 horas antes da retirada da esponja. Foram utilizados tres reprodutores da Raca Canarias, foi utilizado dose inseminante de 150 x 106 de espermatozoides viaveis. Para resfriar e manter o semen a 5o C foi utilizado o BotutainerR (Biotech Botucatu, Reproducao Animal, Botucatu - SP) adaptado. As analises estatisticas foram realizadas utilizando-se o pacote computacional SAEG (2009). Nao houve diferenca (P>0,05) entre os padroes seminais para os diferentes periodos de resfriamento (T24 - 58,8% }11,1 de motilidade e 2,9 }0,5 de vigor; T48 - 51,3% }2,5 de motilidade e 2,8 }0,3 de vigor), o que permitiu obter taxas de paricao similares em ambos os tratamentos (T24-26,5% e T48-21,5%). A eficiencia dos protocolos testados permitiu a disseminacao de genetica caprina na Republica de Cabo Verde. Houve correlacao (r = 0,27; P 0.05) between the seminal patterns for the different periods of cooling (T24 - 58.8%±11.1 for motility and 2.9±0.5 for strength; T48 - 51.3%±2.5 for motility and 2.8±0.3 for strength), which allowed to obtain similar pregnancy rates in both treatments (T24 – 26.5% and T48 - 21,5%). The efficiency of the tested protocols allowed the dissemination of goat’s genetic material in the Republic of Cape Verde. There was a correlation (r = 0.27, P < 0.05) between the range of sponge withdrawal to artificial insemination (IRIA) with the depth of semen deposition (PROF). There was also a correlation (r = 0.29, P < 0.05) between IRIA and the calving rate (PARI). Statistical analysis was done in the computer package SAEG (2009). It was concluded that goat semen, cooled for 48 hours at 5 oC, has the same fertility that semen cooled for 24 hours at 5 oC.Dissertação (Mestrado em Ciência Veterinárias) - Universidade Federal do Paraná, Curitiba. Orientador: José Antônio de Freitas; Co-orientador: Jeferson Ferreira da Fonseca, Embrapa Caprinos e Ovinos (CNPC)

The History of Cosmological Star Formation: Three Independent Approaches and a Critical Test Using the Extragalactic Background Light

Taking three independent approaches, we investigate the simultaneous constraints set on the cosmic star formation history from various observations, including stellar mass density and extragalactic background light (EBL). We compare results based on: 1) direct observations of past light-cone, 2) a model using local fossil evidence constrained by SDSS observations at z~0 (the `Fossil' model), and 3) theoretical ab initio models from three calculations of cosmic star formation history: (a) new (1024)^3 Total Variation Diminishing (TVD) cosmological hydrodynamic simulation, (b) analytic expression of Hernquist & Springel based on cosmological Smoothed Particle Hydrodynamics (SPH) simulations, and (c) semi-analytic model of Cole et al. We find good agreement among the three independent approaches up to the order of observational errors, except that all the models predict bolometric EBL of I_tot ~= 37-52 nW m^-2 sr^-1, which is at the lower edge of the the observational estimate by Hauser & Dwek. We emphasize that the Fossil model that consists of two components -- spheroids and disks --, when normalized to the local observations, provides a surprisingly simple but accurate description of the cosmic star formation history and other observable quantities. Our analysis suggests that the consensus global parameters at z=0 are: Omega_* = 0.0023+-0.0004, I_EBL = 43+-7 nW m^-2 sr^-1 rho_SFR=(1.06+-0.22)e-2 Msun yr^-1 Mpc^-3, j_bol = (3.1+-0.2)e8 Lsun Mpc^-3.Comment: 40 page, 10 figures. ApJ in press. Matched to the accepted versio

Galaxy Peculiar Velocities From Large-Scale Supernova Surveys as a Dark Energy Probe

Upcoming imaging surveys such as the Large Synoptic Survey Telescope will repeatedly scan large areas of sky and have the potential to yield million-supernova catalogs. Type Ia supernovae are excellent standard candles and will provide distance measures that suffice to detect mean pairwise velocities of their host galaxies. We show that when combining these distance measures with photometric redshifts for either the supernovae or their host galaxies, the mean pairwise velocities of the host galaxies will provide a dark energy probe which is competitive with other widely discussed methods. Adding information from this test to type Ia supernova photometric luminosity distances from the same experiment, plus the cosmic microwave background power spectrum from the Planck satellite, improves the Dark Energy Task Force Figure of Merit by a factor of 1.8. Pairwise velocity measurements require no additional observational effort beyond that required to perform the traditional supernova luminosity distance test, but may provide complementary constraints on dark energy parameters and the nature of gravity. Incorporating additional spectroscopic redshift follow-up observations could provide important dark energy constraints from pairwise velocities alone. Mean pairwise velocities are much less sensitive to systematic redshift errors than the luminosity distance test or weak lensing techniques, and also are only mildly affected by systematic evolution of supernova luminosity.Comment: 18 pages; 4 figures; 4 tables; replaced to match the accepted versio

Containerless processing of beryllium

Melting and solidification of a beryllium alloy containing 1.5% BeO by weight in the weightless environment of space has produced cast beryllium with a relatively uniform dispersion of BeO throughout. Examination of the cast material shows that it is coarse grained, although the BeO is not heavily agglomerated in the flight specimen. Ground based comparison experiments show extreme agglomeration and segregation of BeO, resulting in large zones which are practically free of the oxide. Several postulated hypotheses for the failure to grain refine the beryllium are formulated. These are: (1) spherodization of the BeO particles during specimen preparation and during the molten phase of the experiment; (2) loss of nucleation potency through aging in the molten phase; and (3) inability of BeO to act as a grain refiner for beryllium. Further investigation with non spherodized particles and shorter dwell times molten may delineate which of these hypotheses are valid. The results of this flight experiment indicate that the weightless environment of space is an important asset in conducting research to find grain refiners for beryllium and other metals for which cast dispersions of grain refining agents cannot be prepared terrestrially due to gravitationally driven settling and agglomeration

Protein and sensory quality of a food supplement formulated for the elderly

This study aimed to evaluate the composition, the protein quality, and the acceptability of a powder dietary supplement formulated for elderly people. The centesimal composition was analysed according to A.O.A.C. methods and the protein quality was assessed in weaning rats, by comparing Protein Efficiency Ratio (PER), Net Protein Ratio (NPR), and True Digestibility (TD) of the supplement with a casein-control based on AIN-93G diet. For the acceptance test samples of four flavours of the supplement dissolved in whole milk were offered to each judge, in monadic form. To assess the overall acceptability a scale of seven points was used. The sensory panel was composed of 121 Brazilian panellists, with mean age of 68.28±5.78 years. The supplement is promising in reaching the nutritional demands of the elderly, providing high content of protein and fibre and low content of fat. The values found for PER and NPR were shown to be superior to the control group of casein (P<0.05) and the digestibility was higher than 90%, showing that the supplement presented characteristics of a high nutritional value protein source. The supplements with banana, vanilla, and strawberry flavour were the most accepted and did not differ significantly for the overall acceptability

Effects of high temperature on survival, symbiotic performance and genomic modifications of bean nodulating Rhizobium strains.

High temperatures can affect the survival, establishment and symbiotic properties of Rhizobium strains. Bean nodulating Rhizobium strains are considered particularly sensitive because on this strains genetic recombinations and/or deletions occur frequently, thus compromising the use of these bacteria as inoculants. Rhizobium tropici and R. leguminosarum bv. phaseoli strains isolated from cerrado soils were exposed to thermal stress and the strains' growth, survival and symbiotic relationships as well as alterations in their genotypic and phenotypic characteristics were analysed. After successive thermal shocks at 45 degrees C for four hours, survival capacity appeared to be strain-specific, independent of thermo-tolerance and was more apparent in R. tropici strains. Certain R. leguminosarum bv. phaseoli strains had significant alterations in plant dry weight and DNA patterns obtained by AP-PCR method. Rhizobium tropici strains (with the exception of FJ2.21) were more stable than R. leguminosarum bv. phaseoli strains because no significant phenotypic alterations were observed following thermal treatments and they maintained their original genotypic pattern after inoculation in plants.

Thunderstorm and Lightning Characteristics Associated With Sprites in Brazil

A study of the thunderstorm and cloud-ground lightning characteristics associated with sprite events observed in Brazil is presented. The study is based on ground and aircraft sprite observations with high sensitivity intensified CCD cameras of six different thunderstorms, GOES satellite infrared images, radar and lightning network data. A total of eighteen transient optical events were recorded at three different days in 2002 and 2003, sixteen of which exhibited vertical structures typically associated with sprites. Four thunderstorms were associated with two different cold fronts, one with a Mesoscale Convective System, and one was a local isolated thunderstorm. The sprites occurred during time periods when the percentage of positive flashes was higher than the average percentage for the storm lifetime. The lightning associated with the sprite events was all positive flashes with a mean peak current higher than the mean value for all flashes in the storms

Fratura Proximal do Fémur Bilateral. Incidência e Fatores de Risco de Fratura Contralateral

Nos doentes com fratura osteoporótica da extremidade proximal do fémur, pouco é conhecido sobre a incidência e fatores de risco de fratura contralateral da extremidade proximal do fémur. O objetivo deste trabalho foi, através de um estudo retrospetivo determinar a incidência e os fatores de risco para fratura bilateral da extremidade proximal do fémur não contemporânea. Foram analisados os processos de 1911 doentes com fratura da extremidade proximal do fémur entre 2003 e 2009. Os dados recolhidos sobre as fraturas, tratamentos e comorbilidades foram trabalhados estatisticamente. Um total de 64 doentes (3,24%) teve fratura bilateral da extremidade proximal do fémur, com uma média de idades acima dos 80 anos. Determinou-se que existe uma relação direta entre o tipo da primeira e segunda fratura (intracapsular vs extraapsular), e que 70% das segundas fraturas ocorrem nos primeiros três anos após fratura. Das comorbilidades verificou-se que a doença de Parkinson, Hipertensão Arterial, doença Cardíaca, Anemia e alterações da Visão representam um risco acrescido para fratura contralateral da extremidade proximal do fémur. Propomos um follow-up mais rigoroso nos primeiros três anos após a primeira fratura e estabelecidas melhores formas de prevenção de fraturas e otimização das comorbilidades nos doentes com fatores de risco