1,143 research outputs found

    The impact of hypoxia on tumor-associated macrophages

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    Erhebung der Grundlagen für die bessere Vermarktung von nach besonderen Richtlinien erzeugten landwirtschaftlichen Produkten aus dem Oberrheingebiet

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    Die vorliegende Untersuchung basiert auf einer Situationsanalyse der Produktions- und Marktstrukturen der regionalen Landwirtschaft. Neben dem Nachfrageverhalten sowie den Erwartungen und Wünschen der Verbraucher und regionalen Marktpartner der Landwirtschaft (Mikroumfeld) werden zudem übergeordnete physische, gesellschaftliche, politische und ökonomische Faktoren (Makroumfeld), die die Ausrichtung der regionalen Landwirtschaft beeinflussen, betrachtet. Die Analyse des Mikro- und Makroumfeldes setzt sich aus folgenden Projektteilen zusammen: - Analyse der landwirtschaftlichen Produktion und ihres Umfeldes, - Analyse der landwirtschaftlichen Vermarktungsstruktur und des Grades der Vernetzung der Landwirtschaft mit ihren regionalen Marktpartnern, - Analyse des Kaufverhaltens und der Präferenzen bei Verbrauchern bezüglich regional und umweltgerecht erzeugter Produkte in verschiedenen Markttypen (Biomarkt/ Naturkostgeschäft, Supermarkt sowie Verbrauchermarkt/Einkaufszentrum), - Analyse des Grossverbrauchermarktes (Einrichtungen der Gemeinschaftsverpflegung) hinsichtlich des Einsatzes von regionalen und umweltgerecht erzeugten Agrarprodukten, - Untersuchung der grenzüberschreitenden Aktivitäten der Landwirtschaft und ihrer Marktpartner in der REGIO, - Systematisierung und Bewertung der handelsrechtlichen Hemmnisse im grenzüberschreitenden Warenaustausch. Da die Bedeutung einzelner Produktgruppen, wie auch einzelner Vermarktungswege im Untersuchungsgebiet variieren, konzentriert sich die Untersuchung auf die für die drei Regionen jeweils wichtigsten Nahrungsmittelmärkte Brotgetreide, Milch, Fleisch sowie Obst und Gemüse. Zusätzlich werden produktübergreifend die Märkte für integriert sowie für ökologisch erzeugte Nahrungsmittel analysiert. Aufbauend auf die im Rahmen dieser Arbeit erstellten Umfeldanalyse sowie die Schätzung der weiteren Entwicklung der wichtigsten Einflussfaktoren der landwirtschaftlichen Erzeugung und Vermarktung, werden, mit Hilfe einer produktbezogenen Betrachtung der fördernden und hemmenden Faktoren, die Möglichkeiten für eine stärkere regionale Marktausrichtung der Landwirtschaft unter besonderer Berücksichtigung der ökologischen und integrierten Produktion beurteilt

    J004457+4123 (Sharov 21): not a remarkable nova in M31 but a background quasar with a spectacular UV flare

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    We announce the discovery of a quasar behind the disk of M31, which was previously classified as a remarkable nova in our neighbour galaxy. The paper is primarily aimed at the outburst of J004457+4123 (Sharov 21), with the first part focussed on the optical spectroscopy and the improvement in the photometric database. Both the optical spectrum and the broad band spectral energy distribution of Sharov 21 are shown to be very similar to that of normal, radio-quiet type 1 quasars. We present photometric data covering more than a century and resulting in a long-term light curve that is densely sampled over the past five decades. The variability of the quasar is characterized by a ground state with typical fluctuation amplitudes of ~0.2 mag around B~20.5, superimposed by a singular flare of ~2 yr duration (observer frame) with the maximum at 1992.81 where the UV flux has increased by a factor of ~20. The total energy in the flare is at least three orders of magnitudes higher than the radiated energy of the most luminous supernovae, provided that it comes from an intrinsic process and the energy is radiated isotropically. The profile of the flare light curve appears to be in agreement with the standard predictions for a stellar tidal disruption event where a ~10 M_sun giant star was shredded in the tidal field of a ~2...5 10^8 M_sun black hole. The short fallback time derived from the light curve requires an ultra-close encounter where the pericentre of the stellar orbit is deep within the tidal disruption radius. Gravitational microlensing provides an alternative explanation, though the probability of such a high amplification event is very low.Comment: Accepted for publication in Astronomy and Astrophysics, 14 pages, 11 figure

    A Transiting Jupiter Analog

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    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of (0.91±0.02)(0.91\pm0.02) RJupR_{\mathrm{Jup}}, a low orbital eccentricity (0.060.04+0.100.06_{-0.04}^{+0.10}) and an equilibrium temperature of (131±3)(131\pm3) K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric coverage, we are able to uniquely and precisely measure the orbital period of this post snow-line planet (1071.2323±0.00061071.2323\pm0.0006 d), paving the way for follow-up of this K=11.8K=11.8 mag target.Comment: 14 pages, 10 figures. Accepted to ApJ. Posteriors available at https://github.com/CoolWorlds/Kepler-167-Posterior

    Discovery of a Transiting Planet Near the Snow-Line

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    In most theories of planet formation, the snow-line represents a boundary between the emergence of the interior rocky planets and the exterior ice giants. The wide separation of the snow-line makes the discovery of transiting worlds challenging, yet transits would allow for detailed subsequent characterization. We present the discovery of Kepler-421b, a Uranus-sized exoplanet transiting a G9/K0 dwarf once every 704.2 days in a near-circular orbit. Using public Kepler photometry, we demonstrate that the two observed transits can be uniquely attributed to the 704.2 day period. Detailed light curve analysis with BLENDER validates the planetary nature of Kepler-421b to >4 sigmas confidence. Kepler-421b receives the same insolation as a body at ~2AU in the Solar System and for a Uranian albedo would have an effective temperature of ~180K. Using a time-dependent model for the protoplanetary disk, we estimate that Kepler-421b's present semi-major axis was beyond the snow-line after ~3Myr, indicating that Kepler-421b may have formed at its observed location.Comment: 14 pages, 10 figures, 3 tables. Accepted in Ap

    Geometrical constraints on the origin of timing signals from black holes

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    We present a systematic study of the orbital inclination effects on black hole transients fast time-variability properties. We have considered all the black hole binaries that have been densely monitored by the Rossi X-ray Timing Explorer satellite. We find that the amplitude of low-frequency quasi-periodic oscillations (QPOs) depends on the orbital inclination. type-C QPOs are stronger for nearly edge-on systems (high inclination), while type-B QPOs are stronger when the accretion disc is closer to face-on (low inclination). Our results also suggest that the noise associated with type-CQPOs is consistent with being stronger for low-inclination sources, while the noise associated with type-B QPOs seems inclination independent. These results are consistent with a geometric origin of the type-C QPOs - for instance arising from relativistic precession of the inner flow within a truncated disc - while the noise would correspond to intrinsic brightness variability from mass accretion rate fluctuations in the accretion flow. The opposite behaviour of type-B QPOs - stronger in low-inclinations sources supports the hypothesis that type-B QPOs are related to the jet, the power of which is the most obvious measurable parameter expected to be stronger in nearly face-on sources

    Physical fitness is associated with neural activity during working memory performance in major depressive disorder

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    Background: Deficits in cognition like working memory (WM) are highly prevalent symptoms related to major depressive disorder (MDD). Neuroimaging studies have described frontoparietal abnormalities in patients with MDD as a basis for these deficits. Based on research in healthy adults, it is hypothesized that increased physical fitness might be a protective factor for these deficits in MDD. However, the relationship between physical fitness and WM-related neural activity and performance has not been tested in MDD, to date. Understanding these associations could inform the development of physical exercise interventions in MDD. Methods: Within a larger project, 111 (53female) MDD outpatients and 56 (34female) healthy controls performed an n-back task (0-, 1-, 2-, 3-back) during functional Magnetic Resonance Imaging. Physical fitness from a graded exercise test on a cycle ergometer was performed by 106 MDD patients. Results: Patients showed reduced performance particularly at high loads of the n-back WM task and prolonged reaction times at all n-back loads. A whole-brain interaction analysis of group by WM load revealed reduced neural activity in six frontoparietal clusters at medium and high WM loads in MDD patients compared to healthy controls. Analysis of covariance within the MDD sample showed that physical fitness was associated with neural activity in right and left superior parietal lobules. Externally defined Regions of Interest confirmed this analysis. Conclusions: Results indicate frontoparietal hypoactivity in MDD at high demands, arguing for decreased WM capacity. We demonstrate a parietal fitness correlate which could be used to guide future research on effects of exercise on cognitive functioning in MDD

    Deep XMM-Newton observations of the northern disc of M31. I. Source catalogue

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    We carried out new observations of two fields in the northern ring of M31 with XMM-Newton with two exposures of 100 ks each and obtained a complete list of X-ray sources down to a sensitivity limit of ~7 x 10^34 erg s^-1 (0.5 - 2.0 keV). The major objective of the observing programme was the study of the hot phase of the ISM in M31. The analysis of the diffuse emission and the study of the ISM is presented in a separate paper. We analysed the spectral properties of all detected sources using hardness ratios and spectra if the statistics were high enough. We also checked for variability. We cross-correlated the source list with the source catalogue of a new survey of the northern disc of M31 carried out with Chandra and Hubble (Panchromatic Hubble Andromeda Treasury, PHAT) as well as with other existing catalogues. We detected a total of 389 sources, including 43 foreground stars and candidates and 50 background sources. Based on the comparison to the Chandra/PHAT survey, we classify 24 hard X-ray sources as new candidates for X-ray binaries (XRBs). In total, we identified 34 XRBs and candidates and 18 supernova remnants (SNRs) and candidates. Three of the four brightest SNRs show emission mainly below 2 keV, consistent with shocked ISM. The spectra of two of them also require an additional component with a higher temperature. The SNR [SPH11] 1535 has a harder spectrum and might suggest that there is a pulsar-wind nebula inside the SNR. We find five new sources showing clear time variability. We also studied the spectral properties of the transient source SWIFT J004420.1+413702, which shows significant variation in flux over a period of seven months (June 2015 to January 2016) and associated change in absorption. Based on the likely optical counterpart detected in the Chandra/PHAT survey, the source is classified as a low-mass X-ray binary.Comment: Accepted for publication in A&
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