180 research outputs found

    On the trails of Josias Braun-Blanquet II : first results from the 12th EDGG Field Workshop studying the dry grasslands of the inneralpine dry valleys of Switzerland

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    The 12th EDGG Field Workshop took place from 11 to 19 May 2019, organised by the Vegetation Ecology Group of the Institute of Natural Resource Sciences (IUNR) of the Zurich University of Applied Sciences (ZHAW). Like in the 11th Field Workshop in Austria, the main target was the "Inneralpine Trockenvegetation" (Festuco-Brometea and Sedo-Scleranthetea), which was first extensively sampled by Josias Braun-Blanquet and collaborators during the 1950s. We visited the Rhône valley in the cantons of Vaud and Valais, one of the most ex-treme xerothermic islands of the Alps and the Rhine and Inn valleys in the canton of Grison. In total, 30 nested-plot series (EDGG biodi-versity plots) of 0.0001 to 100 m² and 82 plots of 10 m² were sampled in meso-xeric, xeric and rocky grasslands of 25 different sites, rang-ing from 500 to 1,656 m a.s.l., under different topographic, bedrock and landuse conditions. All vascular plants, bryophytes and lichens were recorded in each plot, along with their cover values. We found on average 28.9 vascular plants on 10 m²; which was the lowest mean species richness of any previous EDGG Field Workshop. These values are comparable to the average species richness values of dry grasslands of the Aosta valley in Italy. The data sampled will be used to understand the biodiversity patterns regionally and in the Palae-arctic context as well as to place the Swiss dry grasslands in the modern European syntaxonomic system

    The Bursty Star Formation Histories of Low-mass Galaxies at 0.4<z<10.4<z<1 Revealed by Star Formation Rates Measured from Hβ\beta and FUV

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    We investigate the burstiness of star formation histories (SFHs) of galaxies at 0.4<z<10.4<z<1 by using the ratio of star formation rates (SFRs) measured from Hβ\beta and FUV (1500 \AA) (Hβ\beta--to--FUV ratio). Our sample contains 164 galaxies down to stellar mass (M*) of 108.5M10^{8.5} M_\odot in the CANDELS GOODS-N region, where Team Keck Redshift Survey DEIMOS spectroscopy and HST/WFC3 F275W images from CANDELS and Hubble Deep UV Legacy Survey are available. When the {\it ratio} of Hβ\beta- and FUV-derived SFRs is measured, dust extinction correction is negligible (except for very dusty galaxies) with the Calzetti attenuation curve. The Hβ\beta--to--FUV ratio of our sample increases with M* and SFR. The median ratio is \sim0.7 at M*108.5M\sim10^{8.5} M_\odot (or SFR0.5M/yr\sim 0.5 M_\odot/yr) and increases to \sim1 at M*1010M\sim10^{10} M_\odot (or SFR 10M/yr\sim 10 M_\odot/yr). At M*<109.5M<10^{9.5} M_\odot, our median Hβ\beta--to--FUV ratio is lower than that of local galaxies at the same M*, implying a redshift evolution. Bursty SFH on a timescale of a few tens of megayears on galactic scales provides a plausible explanation of our results, and the importance of the burstiness increases as M* decreases. Due to sample selection effects, our Hβ\beta--to--FUV ratio may be an upper limit of the true value of a complete sample, which strengthens our conclusions. Other models, e.g., non-universal initial mass function or stochastic star formation on star cluster scales, are unable to plausibly explain our results.Comment: 13 pages, 8 figures. ApJ accepted. The main conclusions are not changed. Major modifications include: (1) to be consistent with the literature, now reporting H\beta--to--FUV ratio (rather than FUV--to--H\beta\ in the first version); (2) detailed discussions on dust extinction correction; (3) new SF bustiness calculation; and (4) enriched discussions in Introductio

    CANDELS/GOODS-S, CDFS, ECDFS: Photometric Redshifts For Normal and for X-Ray-Detected Galaxies

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    We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). The work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revisit multi-wavelength counterparts for published X-ray sources from the 4Ms-CDFS and 250ks-ECDFS surveys, finding reliable counterparts for 1207 out of 1259 sources (96%\sim 96\%). Data used for photometric redshifts include intermediate-band photometry deblended using the TFIT method, which is used for the first time in this work. Photometric redshifts for X-ray source counterparts are based on a new library of AGN/galaxy hybrid templates appropriate for the faint X-ray population in the CDFS. Photometric redshift accuracy for normal galaxies is 0.010 and for X-ray sources is 0.014, and outlier fractions are 4%4\% and 5.4%5.4\% respectively. The results within the CANDELS coverage area are even better as demonstrated both by spectroscopic comparison and by galaxy-pair statistics. Intermediate-band photometry, even if shallow, is valuable when combined with deep broad-band photometry. For best accuracy, templates must include emission lines.Comment: The paper has been accepted by ApJ. The materials we provide are available under [Surveys] > [CDFS] through the portal http://www.mpe.mpg.de/XraySurvey

    Competitive Balance and Consumer Demand in the English Football League

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    Competitive balance in sports leagues is often used to justify revenue sharing agreements. The justification is that competitive balance leads to higher attendance and higher attendance generates more revenues. By sharing revenue, small market teams can afford to pay for high quality talent, assuring more equal distribution of that talent. Unlike US professional leagues, English football operates under a system of relegation and promotion so that at the end of each season the worst performing teams are "relegated" and the top performing teams in the next level down are "promoted". This may serve as an alternative to revenue sharing to maintain competitive balance.Using data from the top English football league (currently the Premiership) from 1888-89 through the 2014-15 season we calculate multiple measures of league competitive balance for each year using both 3-1-0 and 2-1-0 point systems. We then use these measures with available macroeconomic control variables to examine the relationship between competitive balance and match attendance.We find that, counter to related work in US sports leagues, competitive balance in English football is negatively associated with attendance. This is particularly true in the case of the Premiership era, wherein only five teams have won the championship and in the past 10 seasons, the top 4 places of the championship has been dominated by 7 clubs, yet attendance has steadily increased. This result raises questions about the utility of revenue sharing in increasing attendance in English football

    CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field

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    We present a UV-to-mid infrared multi-wavelength catalog in the CANDELS/GOODS-S field, combining the newly obtained CANDELS HST/WFC3 F105W, F125W, and F160W data with existing public data. The catalog is based on source detection in the WFC3 F160W band. The F160W mosaic includes the data from CANDELS deep and wide observations as well as previous ERS and HUDF09 programs. The mosaic reaches a 5σ\sigma limiting depth (within an aperture of radius 0.17 arcsec) of 27.4, 28.2, and 29.7 AB for CANDELS wide, deep, and HUDF regions, respectively. The catalog contains 34930 sources with the representative 50% completeness reaching 25.9, 26.6, and 28.1 AB in the F160W band for the three regions. In addition to WFC3 bands, the catalog also includes data from UV (U-band from both CTIO/MOSAIC and VLT/VIMOS), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), and infrared (HST/WFC3 F098M, VLT/ISAAC Ks, VLT/HAWK-I Ks, and Spitzer/IRAC 3.6, 4.5, 5.8, 8.0 μ\mum) observations. The catalog is validated via stellar colors, comparison with other published catalogs, zeropoint offsets determined from the best-fit templates of the spectral energy distribution of spectroscopically observed objects, and the accuracy of photometric redshifts. The catalog is able to detect unreddened star-forming (passive) galaxies with stellar mass of 10^{10}M_\odot at a 50% completeness level to z\sim3.4 (2.8), 4.6 (3.2), and 7.0 (4.2) in the three regions. As an example of application, the catalog is used to select both star-forming and passive galaxies at z\sim2--4 via the Balmer break. It is also used to study the color--magnitude diagram of galaxies at 0<z<4.Comment: The full resolution article is now published in ApJS (2013, 207, 24). 22 pages, 21 figures, and 5 tables. The catalogue is available on the CANDELS website: http://candels.ucolick.org/data_access/GOODS-S.html MAST: http://archive.stsci.edu/prepds/candels and Rainbow Database: https://arcoiris.ucolick.org/Rainbow_navigator_public and https://rainbowx.fis.ucm.es/Rainbow_navigator_publi

    The Science Case for an Extended Spitzer Mission

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    Although the final observations of the Spitzer Warm Mission are currently scheduled for March 2019, it can continue operations through the end of the decade with no loss of photometric precision. As we will show, there is a strong science case for extending the current Warm Mission to December 2020. Spitzer has already made major impacts in the fields of exoplanets (including microlensing events), characterizing near Earth objects, enhancing our knowledge of nearby stars and brown dwarfs, understanding the properties and structure of our Milky Way galaxy, and deep wide-field extragalactic surveys to study galaxy birth and evolution. By extending Spitzer through 2020, it can continue to make ground-breaking discoveries in those fields, and provide crucial support to the NASA flagship missions JWST and WFIRST, as well as the upcoming TESS mission, and it will complement ground-based observations by LSST and the new large telescopes of the next decade. This scientific program addresses NASA's Science Mission Directive's objectives in astrophysics, which include discovering how the universe works, exploring how it began and evolved, and searching for life on planets around other stars.Comment: 75 pages. See page 3 for Table of Contents and page 4 for Executive Summar

    Establishing a maturity model for design automation in sales-delivery processes of ETO products

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    Short delivery times are considered a competitive advantage in the engineer-to-order (ETO) sector. Design-related tasks contribute to a substantial amount of delivery times and costs since ETO products have to be either fully developed or adapted to customer specifications within tendering or order fulfillment. Approaches aiming at a computerised automation of tasks related to the design process, often termed design automation or knowledge-based engineering, are generally regarded as an effective means to achieve lead time and cost reductions while maintaining, or even improving product quality. In this study we propose a maturity model as a framework for analyzing and improving such activities in ETO companies. We contribute to the literature in being the first to investigate design automation in the ETO sector from a maturity perspective. Beyond that, we extend the extant literature on design automation, which is of a highly technical nature, by providing a framework considering organizational and managerial aspects. The findings indicate that five different levels of maturity can be achieved across the dimensions strategies, processes, systems, and people. Empirical cases give insight into these different levels. Our investigation draws from extant literature and a comparative case study involving four companies over two years

    Modelling nonlinear dynamics of interacting tipping elements on complex networks: the PyCascades package

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    Tipping elements occur in various systems such as in socio-economics, ecology and the climate system. In many cases, the individual tipping elements are not independent of each other, but they interact across scales in time and space. To model systems of interacting tipping elements, we here introduce the PyCascades open source software package for studying interacting tipping elements (https://doi.org/10.5281/zenodo.4153102). PyCascades is an object-oriented and easily extendable package written in the programming language Python. It allows for investigating under which conditions potentially dangerous cascades can emerge between interacting dynamical systems, with a focus on tipping elements. With PyCascades it is possible to use different types of tipping elements such as double-fold and Hopf types and interactions between them. PyCascades can be applied to arbitrary complex network structures and has recently been extended to stochastic dynamical systems. This paper provides an overview of the functionality of PyCascades by introducing the basic concepts and the methodology behind it. In the end, three examples are discussed, showing three different applications of the software package. First, the moisture recycling network of the Amazon rainforest is investigated. Second, a model of interacting Earth system tipping elements is discussed. And third, the PyCascades modelling framework is applied to a global trade network
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