678 research outputs found

    3D Spectrophotometry of Planetary Nebulae in the Bulge of M31

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    We introduce crowded field integral field (3D) spectrophotometry as a useful technique for the study of resolved stellar populations in nearby galaxies. As a methodological test, we present a pilot study with selected extragalactic planetary nebulae (XPN) in the bulge of M31, demonstrating how 3D spectroscopy is able to improve the limited accuracy of background subtraction which one would normally obtain with classical slit spectroscopy. It is shown that due to the absence of slit effects, 3D is a most suitable technique for spectrophometry. We present spectra and line intensities for 5 XPN in M31, obtained with the MPFS instrument at the Russian 6m BTA, INTEGRAL at the WHT, and with PMAS at the Calar Alto 3.5m Telescope. Using 3D spectra of bright standard stars, we demonstrate that the PSF is sampled with high accuracy, providing a centroiding precision at the milli-arcsec level. Crowded field 3D spectrophotometry and the use of PSF fitting techniques is suggested as the method of choice for a number of similar observational problems, including luminous stars in nearby galaxies, supernovae, QSO host galaxies, gravitationally lensed QSOs, and others.Comment: (1) Astrophysikalisches Institut Potsdam, (2) University of Durham. 18 pages, 11 figures, accepted for publication in Ap

    Relevance of the light signaling machinery for cellulase expression in trichoderma reesei (hypocrea jecorina)

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    <p>Abstract</p> <p>Background</p> <p>In nature, light is one of the most important environmental cues that fungi perceive and interpret. It is known not only to influence growth and conidiation, but also cellulase gene expression. We therefore studied the relevance of the main components of the light perception machinery of <it>Trichoderma reesei </it>(<it>Hypocrea jecorina</it>), ENV1, BLR1 and BLR2, for production of plant cell wall degrading enzymes in fermentations aimed at efficient biosynthesis of enzyme mixtures for biofuel production.</p> <p>Findings</p> <p>Our results indicate that despite cultivation in mostly dark conditions, all three components show an influence on cellulase expression. While we found the performance of the enzyme mixture secreted by a deletion mutant in <it>env1 </it>to be enhanced, the higher cellulolytic activity observed for <it>Δblr2 </it>is mainly due to an increased secretion capacity of this strain. <it>Δblr1 </it>showed enhanced biomass accumulation, but due to its obviously lower secretion capacity still was the least efficient strain in this study.</p> <p>Conclusions</p> <p>We conclude that with respect to regulation of plant cell wall degrading enzymes, the blue light regulator proteins are unlikely to act as a complex. Their regulatory influence on cellulase biosynthesis involves an alteration of protein secretion, which may be due to adjustment of transcription or posttranscriptional regulation of upstream factors. In contrast, the regulatory function of ENV1 seems to involve adjustment of enzyme proportions to environmental conditions.</p

    Diffractive orbits in isospectral billiards

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    Isospectral domains are non-isometric regions of space for which the spectra of the Laplace-Beltrami operator coincide. In the two-dimensional Euclidean space, instances of such domains have been given. It has been proved for these examples that the length spectrum, that is the set of the lengths of all periodic trajectories, coincides as well. However there is no one-to-one correspondence between the diffractive trajectories. It will be shown here how the diffractive contributions to the Green functions match nevertheless in a ''one-to-three'' correspondence.Comment: 20 pages, 6 figure

    An integral-field spectroscopic strong lens survey

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    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS, and nearly Poisson-limited sky subtraction.Comment: Invited contribution to "Gravitational Lensing" Focus Issue of the New Journal of Physics. Some figures at reduced resolutio

    The management of pancreatic cancer. Current expert opinion and recommendations derived from the 8th World Congress on Gastrointestinal Cancer, Barcelona, 2006

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    This article summarizes the expert discussion on the management of pancreatic cancer, which took place during the 8th World Congress on Gastrointestinal Cancer in June 2006 in Barcelona. A multidisciplinary approach to a patient with pancreatic cancer is essential, in order to guarantee an optimal staging, surgery, selection of the appropriate (neo-)adjuvant strategy and chemotherapeutic choice management. Moreover, optimal symptomatic management requires a dedicated team of health care professionals. Quality control of surgery and pathology is especially important in this disease with a high locoregional failure rate. There is now solid evidence in favour of chemotherapy in both the adjuvant and palliative setting, and gemcitabine combined with erlotinib, capecitabine or platinum compounds seems to be slightly more active than gemcitabine alone in advanced pancreatic cancer. There is a place for chemoradiotherapy in selected patients with locally advanced disease, while the role in the adjuvant setting remains controversial. Those involved in the care for patients with pancreatic cancer should be encouraged to participate in well-designed clinical trials, in order to increase the evidence-based knowledge and to make further progres

    A False Start in the Race Against Doping in Sport: Concerns With Cycling’s Biological Passport

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    Professional cycling has suffered from a number of doping scandals. The sport’s governing bodies have responded by implementing an aggressive new antidoping program known as the biological passport. Cycling’s biological passport marks a departure from traditional antidoping efforts, which have focused on directly detecting prohibited substances in a cyclist’s system. Instead, the biological passport tracks biological variables in a cyclist’s blood and urine over time, monitoring for fluctuations that are thought to indirectly reveal the effects of doping. Although this method of indirect detection is promising, it also raises serious legal and scientific concerns. Since its introduction, the cycling community has debated the reliability of indirect biological-passport evidence and the clarity, consistency, and transparency of its use in proving doping violations. Such uncertainty undermines the legitimacy of finding cyclists guilty of doping based on this indirect evidence alone. Antidoping authorities should address these important concerns before continuing to pursue doping sanctions against cyclists solely on the basis of their biological passports

    Measurements of double-helicity asymmetries in inclusive J/ψJ/\psi production in longitudinally polarized p+pp+p collisions at s=510\sqrt{s}=510 GeV

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    We report the double helicity asymmetry, ALLJ/ψA_{LL}^{J/\psi}, in inclusive J/ψJ/\psi production at forward rapidity as a function of transverse momentum pTp_T and rapidity ∣y∣|y|. The data analyzed were taken during s=510\sqrt{s}=510 GeV longitudinally polarized pp++pp collisions at the Relativistic Heavy Ion Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision energy, J/ψJ/\psi particles are predominantly produced through gluon-gluon scatterings, thus ALLJ/ψA_{LL}^{J/\psi} is sensitive to the gluon polarization inside the proton. We measured ALLJ/ψA_{LL}^{J/\psi} by detecting the decay daughter muon pairs ÎŒ+Ό−\mu^+ \mu^- within the PHENIX muon spectrometers in the rapidity range 1.2<∣y∣<2.21.2<|y|<2.2. In this kinematic range, we measured the ALLJ/ψA_{LL}^{J/\psi} to be 0.012±0.0100.012 \pm 0.010~(stat)~±\pm~0.0030.003(syst). The ALLJ/ψA_{LL}^{J/\psi} can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken xx: one at moderate range x≈0.05x \approx 0.05 where recent RHIC data of jet and π0\pi^0 double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-xx region x≈2×10−3x \approx 2\times 10^{-3}. Thus our new results could be used to further constrain the gluon polarization for x<0.05x< 0.05.Comment: 335 authors, 10 pages, 4 figures, 3 tables, 2013 data. Version accepted for publication by Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    The diagnosis and management of gastric cancer: expert discussion and recommendations from the 12th ESMO/World Congress on Gastrointestinal Cancer, Barcelona, 2010

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    Well-recognized experts in the field of gastric cancer discussed during the 12th European Society Medical Oncology (ESMO)/World Congress Gastrointestinal Cancer (WCGIC) in Barcelona many important and controversial topics on the diagnosis and management of patients with gastric cancer. This article summarizes the recommendations and expert opinion on gastric cancer. It discusses and reflects on the regional differences in the incidence and care of gastric cancer, the definition of gastro-esophageal junction and its implication for treatment strategies and presents the latest recommendations in the staging and treatment of primary and metastatic gastric cancer. Recognition is given to the need for larger and well-designed clinical trials to answer many open question
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