3,566 research outputs found

    Discovery of a large set of SNP and SSR genetic markers by high-throughput sequencing of pepper (Capsicum annuum)

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    Genetic markers based on single nucleotide polymorphisms (SNPs) are in increasing demand for genome mapping and fingerprinting of breeding populations in crop plants. Recent advances in high-throughput sequencing provide the opportunity for whole-genome resequencing and identification of allelic variants by mapping the reads to a reference genome. However, for many species, such as pepper (Capsicum annuum), a reference genome sequence is not yet available. To this end, we sequenced the C. annuum cv. "Yolo Wonder" transcriptome using Roche 454 pyrosequencing and assembled de novo 23,748 isotigs and 60,370 singletons. Mapping of 10,886,425 reads obtained by the Illumina GA II sequencing of C. annuum cv. "Criollo de Morclos 334" to the "Yolo Wonder" transcriptome allowed for SNP identification. By setting a threshold value that allows selecting reliable SNPs with minimal loss of information, 11,849 reliable SNPs spread across 5919 isotigs were identified. In addition, 853 single sequence repeats were obtained. This information has been made available online

    Kinetic theory for non-equilibrium stationary states in long-range interacting systems

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    We study long-range interacting systems perturbed by external stochastic forces. Unlike the case of short-range systems, where stochastic forces usually act locally on each particle, here we consider perturbations by external stochastic fields. The system reaches stationary states where external forces balance dissipation on average. These states do not respect detailed balance and support non-vanishing fluxes of conserved quantities. We generalize the kinetic theory of isolated long-range systems to describe the dynamics of this non-equilibrium problem. The kinetic equation that we obtain applies to plasmas, self-gravitating systems, and to a broad class of other systems. Our theoretical results hold for homogeneous states, but may also be generalized to apply to inhomogeneous states. We obtain an excellent agreement between our theoretical predictions and numerical simulations. We discuss possible applications to describe non-equilibrium phase transitions.Comment: 11 pages, 2 figures; v2: small changes, close to the published versio

    Observational Constraints on Higher Order Clustering up to $z\simeq 1

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    Constraints on the validity of the hierarchical gravitational instability theory and the evolution of biasing are presented based upon measurements of higher order clustering statistics in the Deeprange Survey, a catalog of ∌710,000\sim710,000 galaxies with IAB≀24I_{AB} \le 24 derived from a KPNO 4m CCD imaging survey of a contiguous 4∘×4∘4^{\circ} \times 4^{\circ} region. We compute the 3-point and 4-point angular correlation functions using a direct estimation for the former and the counts-in-cells technique for both. The skewness s3s_3 decreases by a factor of ≃3−4\simeq 3-4 as galaxy magnitude increases over the range 17≀I≀22.517 \le I \le 22.5 (0.1â‰Čzâ‰Č0.80.1 \lesssim z \lesssim 0.8). This decrease is consistent with a small {\it increase} of the bias with increasing redshift, but not by more than a factor of 2 for the highest redshifts probed. Our results are strongly inconsistent, at about the 3.5−4σ3.5-4 \sigma level, with typical cosmic string models in which the initial perturbations follow a non-Gaussian distribution - such models generally predict an opposite trend in the degree of bias as a function of redshift. We also find that the scaling relation between the 3-point and 4-point correlation functions remains approximately invariant over the above magnitude range. The simplest model that is consistent with these constraints is a universe in which an initially Gaussian perturbation spectrum evolves under the influence of gravity combined with a low level of bias between the matter and the galaxies that decreases slightly from z∌0.8z \sim 0.8 to the current epoch.Comment: 28 pages, 4 figures included, ApJ, accepted, minor change

    Cryoelectron microscopy of vitrified sections: a new challenge for the analysis of functional nuclear architecture

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    Cryoelectron microscopy of vitrified sections has become a powerful tool for investigating the fine structural features of cellular compartments. In the present study, this approach has been applied in order to explore the ultrastructural morphology of the interphase nucleus in different mammalian cultured cells. Rat hepatoma, Chinese hamster ovary and Potorus kidney cells were cryofixed by high-pressure freezing and the cryosections were examined at low temperature by transmission electron microscopy. Our results show that while the contrast of nuclear structural domains is remarkably homogeneous in hydrated sections, some of them can be recognised due to their characteristic texture. Thus, condensed chromatin appears finely granular and the perichromatin region contains rather abundant fibro-granular elements suggesting the presence of dispersed chromatin fibres and of perichromatin fibrils and granules. The interchromatin space looks homogeneous and interchromatin granules have not been identified under these preparative conditions. In the nucleolus, the most striking feature is the granular component, while the other parts of the nucleolar body, which appear less contrasted, are difficult to resolve. The nuclear envelope is easily recognisable with its regular perinuclear space and nuclear pore complexes. Our observations are discussed in the context of results obtained by other, more conventional electron microscopic method

    Algebraic Correlation Function and Anomalous Diffusion in the HMF model

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    In the quasi-stationary states of the Hamiltonian Mean-Field model, we numerically compute correlation functions of momenta and diffusion of angles with homogeneous initial conditions. This is an example, in a N-body Hamiltonian system, of anomalous transport properties characterized by non exponential relaxations and long-range temporal correlations. Kinetic theory predicts a striking transition between weak anomalous diffusion and strong anomalous diffusion. The numerical results are in excellent agreement with the quantitative predictions of the anomalous transport exponents. Noteworthy, also at statistical equilibrium, the system exhibits long-range temporal correlations: the correlation function is inversely proportional to time with a logarithmic correction instead of the usually expected exponential decay, leading to weak anomalous transport properties

    The malleability of uranium: manipulating the charge-density wave in epitaxial films

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    We report x-ray synchrotron experiments on epitaxial films of uranium, deposited on niobium and tungsten seed layers. Despite similar lattice parameters for these refractory metals, the uranium epitaxial arrangements are different and the strains propagated along the a-axis of the uranium layers are of opposite sign. At low temperatures these changes in epitaxy result in dramatic modifications to the behavior of the charge-density wave in uranium. The differences are explained with the current theory for the electron-phonon coupling in the uranium lattice. Our results emphasize the intriguing possibilities of producing epitaxial films of elements that have complex structures like the light actinides uranium to plutonium.Comment: 6 pages, 6 figure

    High Resolution mid-Infrared Imaging of SN 1987A

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    Using the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope, we have detected and resolved 10 micron emission at the position of the inner equatorial ring (ER) of supernova SN 1987A at day 6067. ``Hot spots'' similar to those found in the optical and near-IR are clearly present. The morphology of the 10 micron emission is globally similar to the morphology at other wavelengths from X-rays to radio. The observed mid-IR flux in the region of SN1987A is probably dominated by emission from dust in the ER. We have also detected the ER at 20 micron at a 4 sigma level. Assuming that thermal dust radiation is the origin of the mid-IR emission, we derive a dust temperature of 180^{+20}_{-10} K, and a dust mass of 1.- 8. 10^{-5} Mo for the ER. Our observations also show a weak detection of the central ejecta at 10 micron. We show that previous bolometric flux estimates (through day 2100) were not significantly contaminated by this newly discovered emission from the ER. If we assume that the energy input comes from radioactive decays only, our measurements together with the current theoretical models set a temperature of 90 leq T leq 100 K and a mass range of 10^{-4} - 2. 10^{-3} Mo for the dust in the ejecta. With such dust temperatures the estimated thermal emission is 9(+/-3) 10^{35} erg s^{-1} from the inner ring, and 1.5 (+/-0.5) 10^{36} erg s^{-1} from the ejecta. Finally, using SN 1987A as a template, we discuss the possible role of supernovae as major sources of dust in the Universe.Comment: aastex502, 14 pages, 4 figures; Accepted for publication in ApJ Content changed: new observations, Referee's comments and suggestion

    Dimensions of football stadium and museum tour experiences: The case of Europe’s most valuable brands

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    In the context of football’s globalisation, some of the most important football clubs (FCs) can currently be classified as ‘entertainment multinationals’. Sport hospitality provides opportunities to maximise club stadiums’ use so that they can increase clubs’ annual turnover and function as branding platforms. This study sought to identify the main narratives shared online about—and the dimensions of—visitors’ experiences with top football brands in stadium tours. The data collected for this research comprised 400 text reviews for 10 European FCs’ stadiums (i.e., 4000 reviews) written by visitors in the post-experience phase. Content analysis of these Web reviews was conducted using Leximancer software. The results confirm the existence of 15 themes: fan, tour, stadium, team, museum, room, staff, game, (best) place, ticket, seating, recommend(ation), food, shop and attraction. Most researchers have examined stadium tours from a supply-side perspective. The present study’s aim was, therefore, to contribute to the existing literature by analysing stadium tours’ dimensions from the visitors’ point of view. Stadium tours and museum visits are important sources of revenue that contribute to FCs’ economic sustainability. Offering outstanding customer experiences is thus of utmost importance to maximise club stadiums’ usage and strengthen fans’ engagement.info:eu-repo/semantics/publishedVersio
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