558 research outputs found

    The use of wild cane, Saccharum hybrid clone Moentai, for windbreak in Hawaii

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    Androgen receptor phosphorylation at serine 308 and serine 791 predicts enhanced survival in castrate resistant prostate cancer patients

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    We previously reported that AR phosphorylation at serine 213 was associated with poor outcome and may contribute to prostate cancer development and progression. This study investigates if specific AR phosphorylation sites have differing roles in the progression of hormone naïve prostate cancer (HNPC) to castrate resistant disease (CRPC). A panel of phosphospecific antibodies were employed to study AR phosphorylation in 84 matched HNPC and CRPC tumours. Immunohistochemistry measured Androgen receptor expression phosphorylated at serine residues 94 (pAR<sub>94</sub>), 308 (pAR<sub>308</sub>), 650(pAR<sub>650</sub>) and 791(pAR<sub>791</sub>). No correlations with clinical parameters were observed for pAR<sub>94</sub> or pAR<sub>650</sub> in HNPC or CRPC tumours. In contrast to our previous observation with serine 213, high pAR<sub>308</sub> is significantly associated with a longer time to disease specific death (p= 0.011) and high pAR<sub>791</sub> expression significantly associated with a longer time to disease recurrence (p= 0.018) in HNPC tumours and longer time to death from disease recurrence (p= 0.040) in CRPC tumours. This observation in CRPC tumours was attenuated in high apoptotic tumours (p= 0.022) and low proliferating tumours (p= 0.004). These results demonstrate that understanding the differing roles of AR phosphorylation is necessary before this can be exploited as a target for castrate resistant prostate cancer

    Nonequilibrium and Nonlinear Dynamics in Geomaterials I : The Low Strain Regime

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    Members of a wide class of geomaterials are known to display complex and fascinating nonlinear and nonequilibrium dynamical behaviors over a wide range of bulk strains, down to surprisingly low values, e.g., 10^{-7}. In this paper we investigate two sandstones, Berea and Fontainebleau, and characterize their behavior under the influence of very small external forces via carefully controlled resonant bar experiments. By reducing environmental effects due to temperature and humidity variations, we are able to systematically and reproducibly study dynamical behavior at strains as low as 10^{-9}. Our study establishes the existence of two strain thresholds, the first, epsilon_L, below which the material is essentially linear, and the second, epsilon_M, below which the material is nonlinear but where quasiequilibrium thermodynamics still applies as evidenced by the success of Landau theory and a simple macroscopic description based on the Duffing oscillator. At strains above epsilon_M the behavior becomes truly nonequilibrium -- as demonstrated by the existence of material conditioning -- and Landau theory no longer applies. The main focus of this paper is the study of the region below the second threshold, but we also comment on how our work clarifies and resolves previous experimental conflicts, as well as suggest new directions of research.Comment: 14 pages, 15 figure

    Linear/circular spectropolarimetry of diffuse interstellar bands

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    Context. The identification of the carriers of diffuse interstellar bands (DIBs) remains one of the long-standing mysteries in astronomy. The detection of a polarisation signal in a DIB profile can be used to distinguish between a dust or gas-phase carrier. The polarisation profile can give additional information on the grain or molecular properties of the absorber. In order to detect and measure the linear and circular polarisation of the DIBs we observed reddened lines of sight showing continuum polarisation. For this study we selected two stars HD 197770 and HD 194279. We used high-resolution (R~64.000) spectropolarimetry in the wavelength range from 3700 to 10480 Angstrom with the ESPaDOnS echelle spectrograph mounted at the CFHT. Results. High S/N and high resolution Stokes V (circular), Q and U (linear) spectra were obtained. We constrained upper limits by a factor of 10 for previously observed DIBs. Furthermore, we analysed ~30 additional DIBs for which no spectropolarimetry data has been obtained before. This included the 9577 A DIB and the 8621 A DIB. Conclusions. The lack of polarisation in 45 DIB profiles suggests that none of the absorption lines is induced by a grain-type carrier. The strict upper limits, less than ~0.01%, derived for the observed lines-of-sight imply that if DIBs are due to gas-phase molecules these carriers have polarisation efficiencies which are at least 6 times, and up to 300 times, smaller than those predicted for grain-related carriers.Comment: 6 pages + 13 pages online material, submitted to A&

    General Relativity in Electrical Engineering

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    In electrical engineering metamaterials have been developed that offer unprecedented control over electromagnetic fields. Here we show that general relativity lends the theoretical tools for designing devices made of such versatile materials. Given a desired device function, the theory describes the electromagnetic properties that turn this function into fact. We consider media that facilitate space-time transformations and include negative refraction. Our theory unifies the concepts operating behind the scenes of perfect invisibility devices, perfect lenses, the optical Aharonov-Bohm effect and electromagnetic analogs of the event horizon, and may lead to further applications

    The Circumnuclear Star-forming Activities along the Hubble Sequence

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    In order to study the circumnuclear star-forming activity along the Hubble sequence, we cross-correlate the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) with the Third Reference Catalog of Bright Galaxies (RC3) to derive a large sample of 1015 galaxies with both morphological and spectral information. Among these, 385 sources are classified as star-forming galaxies and the SDSS fibre covered the circumnuclear regions (0.2 - 2.0 kpc). By using the spectral synthesis method to remove the contribution from the underlying old stellar population, we measure the emission lines fluxes accurately which are then used to estimate the star formation rates(SFRs). Our main findings are that: (1) Early-type spirals show much larger Hα\alpha luminosities and hence higher SFRs, they also suffer more extinctions than late-type ones. The equivalent widths (EWs) of Hα\alpha emission lines show the similar trend, however, the very late types (Sdm \sim Irr) do have large fractions of high EWs. (2) We confirm that Dn(4000)_n(4000) has strong correlation with the strengthes of metallic absorption lines (such as CN band, G band and Mg Ib). Both these lines and the Balmer absorption lines show interesting variations between Sbc to Sd type galaxies. (3) The bar structure tightly relates with the enhanced star forming activity, this effect is even more significant in the early-type spirals. But we should note that the bar structure is not a necessary or sufficient condition for galaxies to harbor circumnuclear star formations.Comment: 14 pages, 15 figures, accepted for publication in A&

    Modeling the emission line sequence of H II galaxies

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    Using a sample of unprecedented size (about 400 objects) of H II galaxies in which the oxygen abundances have been obtained using the temperature derived from the [OIII] 4363/5007 line ratio, we confirm that the H II galaxies form a very narrow sequence in many diagrams relating line ratios and Hbeta equivalent width. We divide our sample in three metallicity bins, each of which is compared with sequences of photoionization models for evolving starbursts with corresponding metallicity. Our aim is to find under what conditions a theoretical sequence can reproduce all the observed trends. Taking into account the presence of an older, non-ionizing stellar population, for which independent indications exist, we find that the simple model of an adiabatic expanding bubble reproduces the observational diagrams very well if account is taken of an aperture correction and the covering factor is assumed to decrease with time exponentially with an e-folding time of 3 Myr. We find that the He II 4686 nebular line emission occurs too frequently and in too wide a range of EW(Hbeta) to be attributable to either the hard radiation field from Wolf-Rayet stars or the X-rays produced by the latest stellar generation. Assuming that the He II 4686 line is due to photoionization by a hot plasma at a temperature of 10^6 K, a total X-ray luminosity of 10^40 - 4x10^40 erg/s is required for at least half of the sources. We find evidence for self-enrichment in nitrogen on a time scale of several Myr, and argue for a possible self-enrichment in oxygen as well.Comment: 15 pages, 6 Postscript figures, to appear in Astronomy & Astrophysic

    Mapping Luminous Blue Compact Galaxies with VIRUS-P: morphology, line ratios and kinematics

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    [abridged] We carry out an integral field spectroscopy (IFS) study of a sample of luminous BCGs, with the aim to probe the morphology, kinematics, dust extinction and excitation mechanisms of their warm interstellar medium (ISM). IFS data for five luminous BCGs were obtained using VIRUS-P, the prototype instrument for the Visible Integral Field Replicable Unit Spectrograph, attached to the 2.7m Harlan J. Smith Telescope at the McDonald Observatory. VIRUS-P consists of a square array of 247 optical fibers, which covers a 109"x109" field of view, with a spatial sampling of 4.2" and a 0.3 filling factor. We observed in the 3550-5850 Angstrom spectral range, with a resolution of 5 A FWHM. From these data we built two-dimensional maps of the continuum and the most prominent emission-lines ([OII]3727, Hgamma, Hbeta and [OIII]5007), and investigate the morphology of diagnostic emission-line ratios and the extinction patterns in the ISM as well as stellar and gas kinematics. Additionally, from integrated spectra we infer total line fluxes and luminosity-weighted extinction coefficients and gas-phase metallicities. All galaxies exhibit an overall regular morphology in the stellar continuum, while their warm ISM morphology is more complex: in II Zw 33 and Mrk 314, the star-forming regions are aligned along a chain-structure; Haro 1, NGC 4670 and III Zw 102 display several salient features, such as extended gaseous filaments and bubbles. A significant intrinsic absorption by dust is present in all galaxies, the most extreme case being III Zw 102. Our data reveal a manifold of kinematical patterns, from overall regular gas and stellar rotation to complex velocity fields produced by structurally and kinematically distinct components.Comment: Accepted for publication in A&A. 16 pages, 10 figure

    Return to Play practices following hamstring injury: A worldwide survey of 131 premier league football teams

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    Purpose: Return-to-play (RTP) is an on-going challenge in professional football. Return-to-play related research is increasing. However, it is unknown to what extent the recommendations presented within research are being implemented by professional football teams, and where there are gaps between research and practice. The purposes of this study were 1) to determine if premier-league football teams worldwide follow a RTP continuum, 2) to identify RTP criteria used, and 3) to understand how RTP decision-making occurs in applied practice.Methods: We sent a structured online survey to practitioners responsible for the RTP programme in 310 professional teams from 34 premier-leagues worldwide. The survey comprised 4 sections, based on hamstring muscle injury: (1) criteria used throughout RTP phases, (2) the frequency with which progression criteria were achieved, (3) RTP decision-making process, and (4) challenges to decision-making.Results: One-hundred and thirty-one teams responded with a completed survey (42%). One-hundred and twenty-four teams (95%) used a continuum to guide RTP, assessing a combination of clinical, functional and psychological criteria to inform decisions to progress. One-hundred and five (80%) teams reported using a shared decision-making approach considering the input of multiple stakeholders. Team hierarchy, match- and player-related factors were common challenges perceived to influence decision-making. Conclusions: General research recommendations for RTP and the beliefs and practices of practitioners appear to match with, the majority of teams assessing functional, clinical and psychological criteria throughout a RTP continuum to inform decision-making which is also shared among key-stakeholders. However, specific criteria, metrics and thresholds used, and the specific involvement, dynamics and interactions of staff during decision-making are not clear

    Optimizing the noise versus bias trade-off for Illumina whole genome expression BeadChips

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    Five strategies for pre-processing intensities from Illumina expression BeadChips are assessed from the point of view of precision and bias. The strategies include a popular variance stabilizing transformation and model-based background corrections that either use or ignore the control probes. Four calibration data sets are used to evaluate precision, bias and false discovery rate (FDR). The original algorithms are shown to have operating characteristics that are not easily comparable. Some tend to minimize noise while others minimize bias. Each original algorithm is shown to have an innate intensity offset, by which unlogged intensities are bounded away from zero, and the size of this offset determines its position on the noise–bias spectrum. By adding extra offsets, a continuum of related algorithms with different noise–bias trade-offs is generated, allowing direct comparison of the performance of the strategies on equivalent terms. Adding a positive offset is shown to decrease the FDR of each original algorithm. The potential of each strategy to generate an algorithm with an optimal noise–bias trade-off is explored by finding the offset that minimizes its FDR. The use of control probes as part of the background correction and normalization strategy is shown to achieve the lowest FDR for a given bias
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