Evolution of magnetic properties and crystallographic texture in electrical steel with large plastic deformation

Deformation leads to a hardening of steel due to an increase in the density of dislocations and a reduction in their mobility, giving rise to a state of elevated residual stresses in the crystal lattice. In the microstructure, one observes an increase in the contribution of crystalline orientations which are unfavorable to the magnetization, as seen, for example, by a decrease in B(50), the magnetic flux density at a field of 50 A/cm. The present study was carried out with longitudinal strips of fully processed non-oriented (NO) electrical steel, with deformations up to 70% resulting from cold rolling in the longitudinal direction. With increasing plastic deformation, the value of B(50) gradually decreases until it reaches a minimum value, where it remains even for larger deformations. On the other hand, the coercive field H(c) continually increases. Magnetometry results and electron backscatter diffraction results are compared and discussed. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3560895]

Electronic properties and hyperfine fields of nickel-related complexes in diamond

We carried out a first-principles investigation on the microscopic properties of nickel-related defect centers in diamond. Several configurations, involving substitutional and interstitial nickel impurities, have been considered either in isolated configurations or forming complexes with other defects, such as vacancies and boron and nitrogen dopants. The results, in terms of spin, symmetry, and hyperfine fields, were compared with the available experimental data on electrically active centers in synthetic diamond. Several microscopic models, previously proposed to explain those data, have been confirmed by this investigation, while some models could be discarded. We also provided insights into the microscopic structure of several of those centers.

Photoluminescence enhancement by gold nanoparticles in Eu(3+) doped GeO(2)-Bi(2)O(3) glasses

We report large photoluminescence (PL) enhancement in Eu(3+)-doped GeO(2)-Bi(2)O(3) glasses containing gold nanoparticles (NPs). Growth of approximate to 1000% in the PL intensity corresponding to the Eu(3+) transition (5)D(0)->(7)F(2), at 614 nm, was observed in comparison with a reference sample that does not contain gold NPs. Other PL bands from 580 to 700 nm are also enhanced. The enhancement of the PL intensity is attributed to the increased local field in the Eu(3+) locations due to the presence of the NPs and the energy transfer from the excited NPs to the Eu(3+) ions.

NEW MICROSATELLITE LOCI FOR WATER YAM (DIOSCOREA ALATA, DIOSCOREACEAE) AND CROSS-AMPLIFICATION FOR OTHER DIOSCOREA SPECIES

Premise of the study: Dioscorea alata L. is one of the most widely distributed species of the genus in the humid and semihumid tropics and is associated with traditional agriculture. Only a few microsatellite markers have been developed so far for this and other Dioscorea species. Methods and Results: We isolated 14 codominant polymorphic microsatellite markers using a microsatellite-enriched genomic library technique. Ten microsatellite loci were selected, and 80 D. alata accessions from different regions in Brazil were evaluated with nine polymorphic loci. The polymorphism information content (PIC) varied from 0.39 to 0.78 and the power discrimination (PD) ranged from 0.15 to 0.91. Six of the markers showed transferability for the species D. bulbifera, D. cayenensis-D. rotundata, and D. trifida. Conclusions: The SSR markers obtained are an important tool for further studies aiming to characterize the genetic diversity in D. alata and other Dioscorea spp. accessions.

DEVELOPMENT OF MICROSATELLITE MARKERS FOR AULONEMIA ARISTULATA (POACEAE) AND CROSS-AMPLIFICATION IN OTHER BAMBOO SPECIES

Premise of the study: Microsatellite primers were developed for Aulonemia aristulata, an endangered species of economic interest, to further describe its genetic variability and population structure. We also tested cross-amplification in 18 other bamboo species. Methods and Results: Using an enrichment genomic library, 13 microsatellite loci were isolated and characterized in A. aristulata. Seven of these loci were polymorphic. Twelve markers were cross-amplified in at least ten of the tested bamboo species. Conclusions: These markers will be useful for studies on the genetic diversity and structure of A. aristulata, which are important for future conservation, management and breeding programs of this species.

The non-equilibrium nature of culinary evolution

Food is an essential part of civilization, with a scope that ranges from the biological to the economic and cultural levels. Here, we study the statistics of ingredients and recipes taken from Brazilian, British, French and Medieval cookery books. We find universal distributions with scale invariant behaviour. We propose a copy-mutate process to model culinary evolution that fits our empirical data very well. We find a cultural 'founder effect' produced by the non-equilibrium dynamics of the model. Both the invariant and idiosyncratic aspects of culture are accounted for by our model, which may have applications in other kinds of evolutionary processes.

Seroprevalence of Kaposi Sarcoma-associated Herpesvirus and Other Serologic Markers in the Brazilian Amazon

To determine the presence of Kaposi sarcoma-associated herpesvirus (KSHV) and other serologic markers, we tested serum specimens of 339 Amerindians, 181 rural non-Amerindians, and 1,133 urban blood donors (13 Amerindians) in the Brazilian Amazon. High KSHV seroprevalence in children and inverse association with herpes simplex virus type 2 indicates predominant nonsexual transmission among Amerindians.

Time variation of some selected topics in bioethical publications

Objective: To analyse the time variation of topics in bioethical publications as a proxy of the relative importance. Methods: We searched the Medline database for bioethics publications using the words ""ethics or bioethics'', and for 360 specific topics publications, associating Medical Subject Heading topic descriptors to those words. We calculated the ratio of bioethics publications to the total publications of Medline, and the ratio of each topic publications to the total bioethics publications, for five-year intervals, from 1970 to 2004. We calculated the time variation of ratios, dividing the difference between the highest and lowest ratio of each topic by its highest ratio. Four topics were described, selected to illustrate different patterns of variation: ""Induced Abortion'', ""Conflict of Interest'', ""Acquired Immunodeficiency Syndrome'', ""Medical Education.'' Results: The ratio of bioethics publications to total Medline publications increased from 0.003 to 0.012. The variation of the topic's ratios was higher than 0.7 for 68% of the topics. The Induced Abortion ratios decreased from 0.12 to 0.02. Conflict of Interest ratios increased from zero to 0.07. The Acquired Immunodeficiency Syndrome ratios were nearly zero in the first three intervals, had a peak of 0.06 during 1985-9, followed by a decrease to 0.01. Medical Education ratios varied few, from 0.04 to 0.03. Conclusions: There was an increase of bioethical publications in the Medline database. The topics in bioethics literature have an important time variation. Some factors were suggested to explain this variation: current legal cases, resolution of the issue, saturation of a discussion and epidemiologic importance.

Increased Levels of NOTCH1, NF-kappa B, and Other Interconnected Transcription Factors Characterize Primitive Sets of Hematopoietic Stem Cells

As previously shown, higher levels of NOTCH1 and increased NF-kappa B signaling is a distinctive feature of the more primitive umbilical cord blood (UCB) CD34+ hematopoietic stem cells (HSCs), as compared to bone marrow ( BM). Differences between BM and UCB cell composition also account for this finding. The CD133 marker defines a more primitive cell subset among CD34+ HSC with a proposed hemangioblast potential. To further evaluate the molecular basis related to the more primitive characteristics of UCB and CD133+ HSC, immunomagnetically purified human CD34+ and CD133+ cells from BM and UCB were used on gene expression microarrays studies. UCB CD34+ cells contained a significantly higher proportion of CD133+ cells than BM (70% and 40%, respectively). Cluster analysis showed that BM CD133+ cells grouped with the UCB cells ( CD133+ and CD34+) rather than to BM CD34+ cells. Compared with CD34+ cells, CD133+ had a higher expression of many transcription factors (TFs). Promoter analysis on all these TF genes revealed a significantly higher frequency ( than expected by chance) of NF-kappa B-binding sites (BS), including potentially novel NF-kappa B targets such as RUNX1, GATA3, and USF1. Selected transcripts of TF related to primitive hematopoiesis and self-renewal, such as RUNX1, GATA3, USF1, TAL1, HOXA9, HOXB4, NOTCH1, RELB, and NFKB2 were evaluated by real-time PCR and were all significantly positively correlated. Taken together, our data indicate the existence of an interconnected transcriptional network characterized by higher levels of NOTCH1, NF-kappa B, and other important TFs on more primitive HSC sets.

Continental passive microwave-based rainfall estimation algorithm: Application to the Amazon Basin

This paper presents a new statistical algorithm to estimate rainfall over the Amazon Basin region using the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). The algorithm relies on empirical relationships derived for different raining-type systems between coincident measurements of surface rainfall rate and 85-GHz polarization-corrected brightness temperature as observed by the precipitation radar (PR) and TMI on board the TRMM satellite. The scheme includes rain/no-rain area delineation (screening) and system-type classification routines for rain retrieval. The algorithm is validated against independent measurements of the TRMM-PR and S-band dual-polarization Doppler radar (S-Pol) surface rainfall data for two different periods. Moreover, the performance of this rainfall estimation technique is evaluated against well-known methods, namely, the TRMM-2A12 [ the Goddard profiling algorithm (GPROF)], the Goddard scattering algorithm (GSCAT), and the National Environmental Satellite, Data, and Information Service (NESDIS) algorithms. The proposed algorithm shows a normalized bias of approximately 23% for both PR and S-Pol ground truth datasets and a mean error of 0.244 mm h(-1) ( PR) and -0.157 mm h(-1)(S-Pol). For rain volume estimates using PR as reference, a correlation coefficient of 0.939 and a normalized bias of 0.039 were found. With respect to rainfall distributions and rain area comparisons, the results showed that the formulation proposed is efficient and compatible with the physics and dynamics of the observed systems over the area of interest. The performance of the other algorithms showed that GSCAT presented low normalized bias for rain areas and rain volume [0.346 ( PR) and 0.361 (S-Pol)], and GPROF showed rainfall distribution similar to that of the PR and S-Pol but with a bimodal distribution. Last, the five algorithms were evaluated during the TRMM-Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) 1999 field campaign to verify the precipitation characteristics observed during the easterly and westerly Amazon wind flow regimes. The proposed algorithm presented a cumulative rainfall distribution similar to the observations during the easterly regime, but it underestimated for the westerly period for rainfall rates above 5 mm h(-1). NESDIS(1) overestimated for both wind regimes but presented the best westerly representation. NESDIS(2), GSCAT, and GPROF underestimated in both regimes, but GPROF was closer to the observations during the easterly flow.

Dynamics and constraints of the massive graviton dark matter flat cosmologies

We discuss the dynamics of the Universe within the framework of the massive graviton cold dark matter scenario (MGCDM) in which gravitons are geometrically treated as massive particles. In this modified gravity theory, the main effect of the gravitons is to alter the density evolution of the cold dark matter component in such a way that the Universe evolves to an accelerating expanding regime, as presently observed. Tight constraints on the main cosmological parameters of the MGCDM model are derived by performing a joint likelihood analysis involving the recent supernovae type Ia data, the cosmic microwave background shift parameter, and the baryonic acoustic oscillations as traced by the Sloan Digital Sky Survey red luminous galaxies. The linear evolution of small density fluctuations is also analyzed in detail. It is found that the growth factor of the MGCDM model is slightly different (similar to 1-4%) from the one provided by the conventional flat Lambda CDM cosmology. The growth rate of clustering predicted by MGCDM and Lambda CDM models are confronted to the observations and the corresponding best fit values of the growth index (gamma) are also determined. By using the expectations of realistic future x-ray and Sunyaev-Zeldovich cluster surveys we derive the dark matter halo mass function and the corresponding redshift distribution of cluster-size halos for the MGCDM model. Finally, we also show that the Hubble flow differences between the MGCDM and the Lambda CDM models provide a halo redshift distribution departing significantly from the those predicted by other dark energy models. These results suggest that the MGCDM model can observationally be distinguished from Lambda CDM and also from a large number of dark energy models recently proposed in the literature.

First stars XIV. Sulfur abundances in extremely metal-poor stars

Context. Precise S abundances are important in the study of the early chemical evolution of the Galaxy. In particular the site of the formation remains uncertain because, at low metallicity, the trend of this alpha-element versus [Fe/H] remains unclear. Moreover, although sulfur is not bound significantly in dust grains in the ISM, it seems to behave differently in DLAs and old metal-poor stars. Aims. We attempt a precise measurement of the S abundance in a sample of extremely metal-poor stars observed with the ESO VLT equipped with UVES, taking into account NLTE and 3D effects. Methods. The NLTE profiles of the lines of multiplet 1 of S I were computed with a version of the program MULTI, including opacity sources from ATLAS9 and based on a new model atom for S. These profiles were fitted to the observed spectra. Results. We find that sulfur in EMP stars behaves like the other alpha-elements, with [S/Fe] remaining approximately constant below [Fe/H] = -3. However, [S/Mg] seems to decrease slightly with increasing [Mg/H]. The overall abundance patterns of O, Na, Mg, Al, S, and K are most closely matched by the SN model yields by Heger & Woosley. The [S/Zn] ratio in EMP stars is solar, as also found in DLAs. We derive an upper limit to the sulfur abundance [S/Fe] < +0.5 for the ultra metal-poor star CS 22949-037. This, along with a previously reported measurement of zinc, argues against the conjecture that the light-element abundance pattern of this star (and by analogy, the hyper iron-poor stars HE 0107-5240 and HE 1327-2326) would be due to dust depletion.

First stars XIII. Two extremely metal-poor RR Lyrae stars

Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < similar to -3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous stars which can be studied at high spectral resolution. Aims. We aim to determine the detailed chemical composition of the two EMP stars CS 30317-056 and CS 22881-039, originally thought to be red horizontal-branch (RHB) stars, and compare it to earlier results for EMP stars as well as to nucleosynthesis yields from various supernova (SN) models. In the analysis, we discovered that our targets are in fact the two most metal-poor RR Lyrae stars known. Methods. Our detailed abundance analysis, taking into account the variability of the stars, is based on VLT/UVES spectra (R similar or equal to 43 000) and 1D LTE OSMARCS model atmospheres and synthetic spectra. For comparison with SN models we also estimate NLTE corrections for a number of elements. Results. We derive LTE abundances for the 16 elements O, Na, Mg, Al, Si, S, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Sr and Ba, in good agreement with earlier values for EMP dwarf, giant and RHB stars. Li and C are not detected in either star. NLTE abundance corrections are newly calculated for O and Mg and taken from the literature for other elements. The resulting abundance pattern is best matched by model yields for supernova explosions with high energy and/or significant asphericity effects. Conclusions. Our results indicate that, except for Li and C, the surface composition of EMP RR Lyr stars is not significantly affected by mass loss, mixing or diffusion processes; hence, EMP RR Lyr stars should also be useful tracers of the chemical evolution of the early Galactic halo. The observed abundance ratios indicate that these stars were born from an ISM polluted by energetic, massive (25-40 M(circle dot)) and/or aspherical supernovae, but the NLTE corrections for Sc and certain other elements do play a role in the choice of model.

Star formation in the intragroup medium and other diagnostics of the evolutionary stages of compact groups of galaxies

Context. Compact groups of galaxies are entities that have high densities of galaxies and serve as laboratories to study galaxy interactions, intergalactic star formation and galaxy evolution. Aims. The main goal of this study is to search for young objects in the intragroup medium of seven compact groups of galaxies: HCG 2, 7, 22, 23, 92, 100 and NGC 92 as well as to evaluate the stage of interaction of each group. Methods. We used Fabry-Perot velocity fields and rotation curves together with GALEX NUV and FUV images and optical R-band and HI maps. Results. (i) HCG 7 and HCG 23 are in early stages of interaction; (ii) HCG 2 and HCG 22 are mildly interacting; and (iii) HCG 92, HCG 100 and NGC 92 are in late stages of evolution. We find that all three evolved groups contain populations of young blue objects in the intragroup medium, consistent with ages < 100 Myr, of which several are younger than < 10 Myr. We also report the discovery of a tidal dwarf galaxy candidate in the tail of NGC 92. These three groups, besides containing galaxies that have peculiar velocity fields, also show extended HI tails. Conclusions. Our results indicate that the advanced stage of evolution of a group, together with the presence of intragroup HI clouds, may lead to star formation in the intragroup medium. A table containing all intergalactic HII regions and tidal dwarf galaxies confirmed to date is appended.

AUTOMATED DETERMINATION OF [Fe/H] AND [C/Fe] FROM LOW-RESOLUTION SPECTROSCOPY

We develop an automated spectral synthesis technique for the estimation of metallicities ([Fe/H]) and carbon abundances ([C/Fe]) for metal-poor stars, including carbon-enhanced metal-poor stars, for which other methods may prove insufficient. This technique, autoMOOG, is designed to operate on relatively strong features visible in even low- to medium-resolution spectra, yielding results comparable to much more telescope-intensive high-resolution studies. We validate this method by comparison with 913 stars which have existing high-resolution and low- to medium-resolution to medium-resolution spectra, and that cover a wide range of stellar parameters. We find that at low metallicities ([Fe/H] less than or similar to -2.0), we successfully recover both the metallicity and carbon abundance, where possible, with an accuracy of similar to 0.20 dex. At higher metallicities, due to issues of continuum placement in spectral normalization done prior to the running of autoMOOG, a general underestimate of the overall metallicity of a star is seen, although the carbon abundance is still successfully recovered. As a result, this method is only recommended for use on samples of stars of known sufficiently low metallicity. For these low- metallicity stars, however, autoMOOG performs much more consistently and quickly than similar, existing techniques, which should allow for analyses of large samples of metal-poor stars in the near future. Steps to improve and correct the continuum placement difficulties are being pursued.