550 research outputs found

    Detection of Phase Jumps of Free Core Nutation of the Earth and their Concurrence with Geomagnetic Jerks

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    We detected phase jumps of the Free Core Nutation (FCN) of the Earth directly from the analysis of the Very Long Baseline Interferometer (VLBI) observation of the Earth rotation for the period 1984-2003 by applying the Weighted Wavelet Z-Transform (WWZ) method and the Short-time Periodogram with the Gabor function (SPG) method. During the period, the FCN had two significant phase jumps in 1992 and 1998. These epochs coincide with the reported occurrence of geomagnetic jerks.Comment: 8 pages, 4 figure

    Mesure de l'excitation et de l'inhibition dans le tissu neuronal en épilepsie par identification d'un modÚle dynamique non linéaire d'activité EEG

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    Le problĂšme posĂ© est d'identifier un modĂšle rĂ©aliste physiologiquement pour interprĂ©ter les signaux EEG rencontrĂ©s en Ă©pilepsie. Ce modĂšle prĂ©sente des non-linĂ©aritĂ©s, et son identification peut ĂȘtre envisagĂ©e suivant diffĂ©rentes approches. Celle qui est prĂ©sentĂ©e passe par la minimisation d'une distance dans un espace de descripteurs, au moyen d'un algorithme Ă©volutionnaire. Des rĂ©sultats en simulation et sur signaux rĂ©els montrent que les valeurs identifiĂ©es permettent effectivement de dĂ©gager et d'interprĂ©ter certaines Ă©volutions caractĂ©ristiques en dĂ©but des crises

    The genus <i>Elaphomyces </i>(<i>Ascomycota</i>, <i>Eurotiales</i>):a ribosomal DNA-based phylogeny and revised systematics of European 'deer truffles'

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    Elaphomyces (‘deer truffles’) is one of the most important ectomycorrhizal fungal genera in temperate and subarctic forest ecosystems, but also one of the least documented in public databases. The current systematics are mainly based on macromorphology, and is not significantly different from that proposed by Vittadini (1831). Within the 49 species recognised worldwide, 23 were originally described from Europe and 17 of these were described before the 20th century. Moreover, very recent phylogenetic treatments of the genus are mainly based on a few extra-European species and most common European species are still poorly documented. Based on an extensive taxonomic sampling mainly made in the biogeographically rich Cantabrian area (Spain), complemented with collections from France, Greece, Italy, Norway, Portugal and Sweden, all currently recognized species in Europe have been sequenced at the ITS and 28S of the rDNA. Combined phylogenetic analyses yielded molecular support to sections Elaphomyces and Ceratogaster (here emended), while a third, basal lineage encompasses the sections Malacodermei and Ascoscleroderma as well as the tropical genus Pseudotulostoma. Species limits are discussed and some taxa formerly proposed as genuine species based on morphology and biogeography are re-evaluated as varieties or forms. Spore size and ornamentation, features of the peridial surface, structure of the peridium, and the presence of mycelium patches attached to the peridial surface emerge as the most significant systematic characters. Four new species: E. barrioi, E. quercicola, E. roseolus and E. violaceoniger, one new variety: E. papillatus var. sulphureopallidus, and two new forms: E. granulatus forma pallidosporus and E. anthracinus forma talosporus are introduced, as well as four new combinations in the genus: E. muricatus var. reticulatus, E. muricatus var. variegatus, E. papillatus var. striatosporus and E. morettii var. cantabricus. Lectotypes and epitypes are designated for most recognised species. For systematic purposes, new infrageneric taxa are introduced: E. sect. Ascoscleroderma stat. nov., E. subsect. Sclerodermei stat. nov., E. subsect. Maculati subsect. nov., E. subsect. Muricati subsect. nov., and E. subsect. Papillati subsect. nov. Lastly, E. laevigatus, E. sapidus, E. sulphureopallidus and E. trappei are excluded from the genus and referred to Rhizopogon roseolus, Astraeus sapidus comb. nov., Astraeus hygrometricus and Terfezia trappei comb. nov. (syn.: Terfezia cistophila), respectively

    Statistical characteristics of formation and evolution of structure in the universe

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    An approximate statistical description of the formation and evolution of structure of the universe based on the Zel'dovich theory of gravitational instability is proposed. It is found that the evolution of DM structure shows features of self-similarity and the main structure characteristics can be expressed through the parameters of initial power spectrum and cosmological model. For the CDM-like power spectrum and suitable parameters of the cosmological model the effective matter compression reaches the observed scales Rwall∌R_{wall}\sim 20 -- 25h−1h^{-1}Mpc with the typical mean separation of wall-like elements DSLSS∌D_{SLSS}\sim 50 -- 70h−1h^{-1}Mpc. This description can be directly applied to the deep pencil beam galactic surveys and absorption spectra of quasars. For larger 3D catalogs and simulations it can be applied to results obtained with the core-sampling analysis. It is shown that the interaction of large and small scale perturbations modulates the creation rate of early Zel'dovich pancakes and generates bias on the SLSS scale. For suitable parameters of the cosmological model and reheating process this bias can essentially improve the characteristics of simulated structure of the universe. The models with 0.3≀Ωm≀0.50.3\leq \Omega_m \leq 0.5 give the best description of the observed structure parameters. The influence of low mass "warm" dark matter particles, such as a massive neutrino, will extend the acceptable range of Ωm\Omega_m and hh.Comment: 20pages, 7 figures, MNRAS in pres

    Virulence characterization of Venturia inaequalis reference isolates on the differential set of Malus hosts

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    A set of differential hosts has recently been identified for 17 apple scab resistance genes in an updated system for defining gene-for-gene (GfG) relationships in the Venturia inaequalis-Malus pathosystem. However, a set of reference isolates characterized for their complementary avirulence alleles is not yet available. In this paper, we report on improving the set of differential hosts for h(7) and propose the apple genotype LPG3-29 as carrying the single major resistance gene Rvi7. We characterized a reference set of 23 V. inaequalis isolates on 14 differential apple hosts carrying major resistance genes under controlled conditions. We identified isolates that were virulent on at least one of the following defined resistance gene hosts: h(1), h(2), h(3), h(4), h(5), h(6), h(7), h(8), h(9), h(10) and h(13). Sixteen different virulence patterns were observed. In general, the isolates carried one to three virulences, but some of them were more complex, with up to six virulences. This set of well-characterized isolates will be helpful for the identification of additional apple scab resistance genes in apple germplasm and the characterization of new GfG relationships to help improve our understanding of the host-pathogen interactions in the V. inaequalis-Malus pathosystem

    The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts

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    We describe the design and data sample from the DEEP2 Galaxy Redshift Survey, the densest and largest precision-redshift survey of galaxies at z ~ 1 completed to date. The survey has conducted a comprehensive census of massive galaxies, their properties, environments, and large-scale structure down to absolute magnitude M_B = -20 at z ~ 1 via ~90 nights of observation on the DEIMOS spectrograph at Keck Observatory. DEEP2 covers an area of 2.8 deg^2 divided into four separate fields, observed to a limiting apparent magnitude of R_AB=24.1. Objects with z < 0.7 are rejected based on BRI photometry in three of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted ~2.5 times more efficiently than in a purely magnitude-limited sample. Approximately sixty percent of eligible targets are chosen for spectroscopy, yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements. Most of the targets which fail to yield secure redshifts are blue objects that lie beyond z ~ 1.45. The DEIMOS 1200-line/mm grating used for the survey delivers high spectral resolution (R~6000), accurate and secure redshifts, and unique internal kinematic information. Extensive ancillary data are available in the DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into one of the richest multiwavelength regions on the sky. DEEP2 surpasses other deep precision-redshift surveys at z ~ 1 in terms of galaxy numbers, redshift accuracy, sample number density, and amount of spectral information. We also provide an overview of the scientific highlights of the DEEP2 survey thus far. This paper is intended as a handbook for users of the DEEP2 Data Release 4, which includes all DEEP2 spectra and redshifts, as well as for the publicly-available DEEP2 DEIMOS data reduction pipelines. [Abridged]Comment: submitted to ApJS; data products available for download at http://deep.berkeley.edu/DR4
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