727 research outputs found

    Relational Fluidity in Collaborative Governance: Unveiling stakeholdersā€™ relating dynamics and their connection to issue framing dynamics in collaborative governance processes

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    The main research question of this thesis is as follows: _How and why do stakeholder relations evolve over time in collaborative governance processes, and how do relating dynamics interplay with the issue framing dynamics?

    Automated supervised classification of variable stars I. Methodology

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    The fast classification of new variable stars is an important step in making them available for further research. Selection of science targets from large databases is much more efficient if they have been classified first. Defining the classes in terms of physical parameters is also important to get an unbiased statistical view on the variability mechanisms and the borders of instability strips. Our goal is twofold: provide an overview of the stellar variability classes that are presently known, in terms of some relevant stellar parameters; use the class descriptions obtained as the basis for an automated `supervised classification' of large databases. Such automated classification will compare and assign new objects to a set of pre-defined variability training classes. For every variability class, a literature search was performed to find as many well-known member stars as possible, or a considerable subset if too many were present. Next, we searched on-line and private databases for their light curves in the visible band and performed period analysis and harmonic fitting. The derived light curve parameters are used to describe the classes and define the training classifiers. We compared the performance of different classifiers in terms of percentage of correct identification, of confusion among classes and of computation time. We describe how well the classes can be separated using the proposed set of parameters and how future improvements can be made, based on new large databases such as the light curves to be assembled by the CoRoT and Kepler space missions.Comment: This paper has been accepted for publication in Astronomy and Astrophysics (reference AA/2007/7638) Number of pages: 27 Number of figures: 1

    Mapping Stakeholdersā€™ Relating Pathways in Collaborative Planning Processes; A Longitudinal Case Study of an Urban Regeneration Partnership

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    This article reports on a longitudinal case study of stakeholdersā€™ relating dynamics in the collaborative planning process concerning the urban regeneration of Katendrecht, an area located in Rotterdam, the Netherlands. Findings challenge the focusā€“typical for collaborative planning literatureā€“on an ā€˜idealā€™ relational setting, characterized by consensus and joint-ness, as a necessary precursor for collaborative success. Analysis reveals the relevance of a ā€˜hybridā€™ relational setting and the potential functionality of relational settings, which emphasize organizational autonomy. Also, analysis shows that relations change through the accumulation of different events, i.e. scaffolding, rather than by single, specific events. Finally, findings point out how in particular group composition/dynamics events impact on stakeholder relations

    Dusty shells surrounding the carbon variables S Scuti and RT Capricorni

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    For the Mass-loss of Evolved StarS (MESS) programme, the unprecedented spatial resolution of the PACS photometer on board the Herschel space observatory was employed to map the dusty environments of asymptotic giant branch (AGB) and red supergiant (RSG) stars. Among the morphologically heterogeneous sample, a small fraction of targets is enclosed by spherically symmetric detached envelopes. Based on observations in the 70 {\mu}m and 160 {\mu}m wavelength bands, we investigated the surroundings of the two carbon semiregular variables S Sct and RT Cap, which both show evidence for a history of highly variable mass-loss. S Sct exhibits a bright, spherically symmetric detached shell, 138" in diameter and co-spatial with an already known CO structure. Moreover, weak emission is detected at the outskirts, where the morphology seems indicative of a mild shaping by interaction of the wind with the interstellar medium, which is also supported by the stellar space motion. Two shells are found around RT Cap that were not known so far in either dust emission or from molecular line observations. The inner shell with a diameter of 188" shows an almost immaculate spherical symmetry, while the outer ~5' structure is more irregularly shaped. MoD, a modification of the DUSTY radiative transfer code, was used to model the detached shells. Dust temperatures, shell dust masses, and mass-loss rates are derived for both targets

    Risk Factors for Arthralgias or Myalgias Associated with Quinupristinā€Dalfopristin Therapy

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90134/1/phco.23.2.159.32078.pd

    The enigmatic nature of the circumstellar envelope and bow shock surrounding Betelgeuse as revealed by Herschel. I. Evidence of clumps, multiple arcs, and a linear bar-like structure

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    Context. The interaction between stellar winds and the interstellar medium (ISM) can create complex bow shocks. The photometers on board the Herschel Space Observatory are ideally suited to studying the morphologies of these bow shocks. Aims. We aim to study the circumstellar environment and wind-ISM interaction of the nearest red supergiant, Betelgeuse. Methods. Herschel PACS images at 70, 100, and 160 micron and SPIRE images at 250, 350, and 500 micron were obtained by scanning the region around Betelgeuse. These data were complemented with ultraviolet GALEX data, near-infrared WISE data, and radio 21 cm GALFA-HI data. The observational properties of the bow shock structure were deduced from the data and compared with hydrodynamical simulations. Results. The infrared Herschel images of the environment around Betelgeuse are spectacular, showing the occurrence of multiple arcs at 6-7 arcmin from the central target and the presence of a linear bar at 9 arcmin. Remarkably, no large-scale instabilities are seen in the outer arcs and linear bar. The dust temperature in the outer arcs varies between 40 and 140 K, with the linear bar having the same colour temperature as the arcs. The inner envelope shows clear evidence of a non-homogeneous clumpy structure (beyond 15 arcsec), probably related to the giant convection cells of the outer atmosphere. The non-homogeneous distribution of the material even persists until the collision with the ISM. A strong variation in brightness of the inner clumps at a radius of 2 arcmin suggests a drastic change in mean gas and dust density some 32 000 yr ago. Using hydrodynamical simulations, we try to explain the observed morphology of the bow shock around Betelgeuse. Conclusions: [abbreviated]Comment: 26 page

    Temporal resolution deficits in the visual fields of MS patients

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    AbstractWe assessed the relationship between temporal resolution and MS-induced neuropathy. A diagnostic strategy comprising assessments of temporal resolution at 16 points in the extra-foveal visual field up to 12Ā° from the fovea was first compared with foveal temporal resolution and with a standard VEP procedure in the same MS patients. At the group level, foveal temporal resolution was less sensitive to demyelination than the 16-point diagnostic strategy, the detection rate of which was comparable to that of the VEP procedure. Cross-sensitivity of the VEP and the 16-point diagnostic procedure was low. Subsequently, the average severity of MS-induced temporal resolution deficits was studied at three retinal loci of the same size but different eccentricities. Foveal deficits were not significantly greater than more peripheral deficits within the central 12Ā°

    Herschel/PACS observations of the 69 Ī¼m\mu m band of crystalline olivine around evolved stars

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    We present 48 Herschel/PACS spectra of evolved stars in the wavelength range of 67-72 Ī¼\mum. This wavelength range covers the 69 Ī¼\mum band of crystalline olivine (Mg2āˆ’2xFe(2x)SiO4\text{Mg}_{2-2x}\text{Fe}_{(2x)}\text{SiO}_{4}). The width and wavelength position of this band are sensitive to the temperature and composition of the crystalline olivine. Our sample covers a wide range of objects: from high mass-loss rate AGB stars (OH/IR stars, MĖ™ā‰„10āˆ’5\dot M \ge 10^{-5} MāŠ™_\odot/yr), through post-AGB stars with and without circumbinary disks, to planetary nebulae and even a few massive evolved stars. The goal of this study is to exploit the spectral properties of the 69 Ī¼\mum band to determine the composition and temperature of the crystalline olivine. Since the objects cover a range of evolutionary phases, we study the physical and chemical properties in this range of physical environments. We fit the 69 Ī¼\mum band and use its width and position to probe the composition and temperature of the crystalline olivine. For 27 sources in the sample, we detected the 69 Ī¼\mum band of crystalline olivine (Mg(2āˆ’2x)Fe(2x)SiO4\text{Mg}_{(2-2x)}\text{Fe}_{(2x)}\text{SiO}_{4}). The 69 Ī¼\mum band shows that all the sources produce pure forsterite grains containing no iron in their lattice structure. The temperature of the crystalline olivine as indicated by the 69 Ī¼\mum band, shows that on average the temperature of the crystalline olivine is highest in the group of OH/IR stars and the post-AGB stars with confirmed Keplerian disks. The temperature is lower for the other post-AGB stars and lowest for the planetary nebulae. A couple of the detected 69 Ī¼\mum bands are broader than those of pure magnesium-rich crystalline olivine, which we show can be due to a temperature gradient in the circumstellar environment of these stars. continued...Comment: Accepted for publication in A&
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