Experimental attempts to improve the efficiency of nutrient utilisation in ruminants

The overall efficiency of nutrient utilisation of dairy cows is primarily affected by the efficiency with which nutrients are used for milk production. Thus, nutrient use efficiency is a key factor in milk production due to its direct influence on total cost of milk production and its environ-mental impact. To optimise nutrient utilisation efficiency nutrient supply should match nutrient demand as close as possible. This requires precise knowledge of nutrient requirements and availability to for digestion and absorption in the rumen and the small intestine as the two main sites of digestion. Therefore, quantifying nutrient requirements and rumen microbial crude protein synthesis of dairy cows are two essential tools to improve current feeding sys-tems for dairy cows. This thesis aimed at contributing to this overall objective by enhancing knowledge on both topics from experimental studies. Urinary allantoin excretion was used as a non-invasive approach to assess rumen microbial crude protein synthesis and delivered a semi-quantitative prediction. Ranking of diets and the magnitude of changes in rumen microbial crude protein synthesis were reflected but the absolute amount was not yet assessable. Provided that future research improves the accuracy of this method, the approach may prove to be a valuable alternative to currents methods under research and production conditions because cannulated animals requiring excessive intervention would no further be required. Also, the approach is not based on the chemical composition of diets fed which is only a poor indication of the duodenal flow of microbial ni-trogen. This was underlined by the results of the prediction of energy density of whole-crop silage as a feedstuff. The prediction based on type of grain and their origin of growing yielded significant enhancements to the prediction that was solely based on proximate constituents. This observation provides further support that biologically based measures are needed to complement chemical composition to improve predictions of the amount of crude protein that is synthesised by rumen microbes. This would aid in optimising diet composition in order to improve the efficiency of nutrient utilisation. An evaluation of interactions between methionine and choline metabolism of dairy cows provided the basis for a theoretically derived specific requirement for methyl groups. Although this hypothesis, based on the re-evaluation of feeding trials on dairy cows with rumen-protected choline administration, would needs experimen-tal verification yet, it may provide a new approach toward a better understanding of methionine requirements at the beginning of the lactation. Moreover, this re-evaluation supported previous results regarding the effectiveness of supplemental rumen-protected choline in diets of dairy cow. The studies reported in this thesis offer attempts to improve the efficiency of nutrient utilisation of dairy cows by a better understanding of nutrient requirements and nutrient supply

‚Organisationen im öffentlichen Austausch’: Zur Karriere von Organisationsfähigkeiten von Schulen im Sozialraum

Goffman's Ansatz ›Individuum im öffentlichen Austausch‹ (1974): lässt sich dies auch auf Organisationen beziehen?Die Verwendung von Goffman für die Organisationsforschung zu diskutieren, scheint angemessen, da die neuere Schulforschung begreift, dass die Schule als Organisation nicht einfach vorausgesetzt werden kann, sondern es verschiedene Grade von Organisationsfähigkeiten gibt, die erst allmählich und nur unter bestimmten Voraussetzungen von individuellen Rollen, Wissen und Fertigkeiten übergehen zu kollektiven Rollen, Wissen und Fertigkeiten (zum Kapazitäten-Ansatz vgl. Feldhoff 2011; AG Schulinspektion 2016).Das gleiche lässt sich nicht nur für Schulen, sondern auch für ein neu herauszubildendes kommunales Bildungsmanagement (KBM) beobachten. Letzteres ist eine neue Organisati­onsform, die im Werden begriffen ist (AG Lernen vor Ort 2016). Schulen, wie auch das KBM, bedienen sich dabei verschiedener (teilweise medialer) Strategien der Sichtbarmachung, was mit zu einer Karriere der Organisationen verhilft. Der Begriff der Karriere lässt dabei zum einen für die Erforschung personaler, zum anderen auch struktureller Prozesselemente verwenden.Im Beitrag wird erörtert, wie Goffmans Konzepte der Karriere und der Territorien des Selbst (persönlicher Raum, Box, Benutzungsraum, Reihenposition, Hülle, Besitzterritorium, Informationsreservat) für eine Analyse von Organisationen fruchtbar gemacht werden können.Hierbei sollen zum einen die Positionierung von Organisationen im Sozialraum besser verstehbar gemacht werden, zum anderen dabei gleichzeitig auftretende Prozesse der Binnenorganisation.Der Beitrag basiert auf einer Meta-Analyse von Daten zweier BMBF-Projekte (zur Schulins­pektion, 2010–2016; und ›Lernen vor Ort‹, 2010-2014), die mittels qualitativer Methoden ausgewertet wurden bzw. werden, die dem Symbolischen Interaktionismus zugerechnet sind

Beratung, Organisation, Profession - Die gescheiterte Professionalisierung in der Organisationsentwicklung, systemischen Beratung und Managementberatung

Kühl S, Bohn U. Beratung, Organisation, Profession - Die gescheiterte Professionalisierung in der Organisationsentwicklung, systemischen Beratung und Managementberatung. In: Schützeichel R, Brüsemeister T, eds. Die beratene Gesellschaft. Zur gesellschaftlichen Bedeutung von Beratung. Opladen: VS Verlag; 2004: 57-77

AstroGrid-D: Grid Technology for Astronomical Science

We present status and results of AstroGrid-D, a joint effort of astrophysicists and computer scientists to employ grid technology for scientific applications. AstroGrid-D provides access to a network of distributed machines with a set of commands as well as software interfaces. It allows simple use of computer and storage facilities and to schedule or monitor compute tasks and data management. It is based on the Globus Toolkit middleware (GT4). Chapter 1 describes the context which led to the demand for advanced software solutions in Astrophysics, and we state the goals of the project. We then present characteristic astrophysical applications that have been implemented on AstroGrid-D in chapter 2. We describe simulations of different complexity, compute-intensive calculations running on multiple sites, and advanced applications for specific scientific purposes, such as a connection to robotic telescopes. We can show from these examples how grid execution improves e.g. the scientific workflow. Chapter 3 explains the software tools and services that we adapted or newly developed. Section 3.1 is focused on the administrative aspects of the infrastructure, to manage users and monitor activity. Section 3.2 characterises the central components of our architecture: The AstroGrid-D information service to collect and store metadata, a file management system, the data management system, and a job manager for automatic submission of compute tasks. We summarise the successfully established infrastructure in chapter 4, concluding with our future plans to establish AstroGrid-D as a platform of modern e-Astronomy.Comment: 14 pages, 12 figures Subjects: data analysis, image processing, robotic telescopes, simulations, grid. Accepted for publication in New Astronom

<i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties

Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data

Gaia Data Release 1. Astrometry: one billion positions, two million proper motions and parallaxes

Context. Gaia Data Release 1 (DR1) contains astrometric results for more than 1 billion stars brighter than magnitude 20.7 based on observations collected by the Gaia satellite during the first 14 months of its operational phase. Aims. We give a brief overview of the astrometric content of the data release and of the model assumptions, data processing, and validation of the results. Methods. For stars in common with the Hipparcos and Tycho-2 catalogues, complete astrometric single-star solutions are obtained by incorporating positional information from the earlier catalogues. For other stars only their positions are obtained, essentially by neglecting their proper motions and parallaxes. The results are validated by an analysis of the residuals, through special validation runs, and by comparison with external data. Results. For about two million of the brighter stars (down to magnitude ∼11.5) we obtain positions, parallaxes, and proper motions to Hipparcos-type precision or better. For these stars, systematic errors depending for example on position and colour are at a level of ±0.3 milliarcsecond (mas). For the remaining stars we obtain positions at epoch J2015.0 accurate to ∼10 mas. Positions and proper motions are given in a reference frame that is aligned with the International Celestial Reference Frame (ICRF) to better than 0.1 mas at epoch J2015.0, and non-rotating with respect to ICRF to within 0.03 mas yr−1 . The Hipparcos reference frame is found to rotate with respect to the Gaia DR1 frame at a rate of 0.24 mas yr−1 . Conclusions. Based on less than a quarter of the nominal mission length and on very provisional and incomplete calibrations, the quality and completeness of the astrometric data in Gaia DR1 are far from what is expected for the final mission products. The present results nevertheless represent a huge improvement in the available fundamental stellar data and practical definition of the optical reference frame

Gaia Data Release 1: Testing parallaxes with local Cepheids and RR Lyrae stars

Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims. In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, which involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with literature estimates and derived new period-luminosity (PL), period-Wesenheit (PW) relations for classical and Type II Cepheids and infrared PL, PL-metallicity (PLZ), and optical luminosity-metallicity (M V -[Fe/H]) relations for the RR Lyrae stars, with zero points based on TGAS. Methods. Classical Cepheids were carefully selected in order to discard known or suspected binary systems. The final sample comprises 102 fundamental mode pulsators with periods ranging from 1.68 to 51.66 days (of which 33 with σ Ω /Ω < 0.5). The Type II Cepheids include a total of 26 W Virginis and BL Herculis stars spanning the period range from 1.16 to 30.00 days (of which only 7 with σ Ω /Ω < 0.5). The RR Lyrae stars include 200 sources with pulsation period ranging from 0.27 to 0.80 days (of which 112 with σ Ω /Ω < 0.5). The new relations were computed using multi-band (V,I,J,K s ) photometry and spectroscopic metal abundances available in the literature, and by applying three alternative approaches: (i) linear least-squares fitting of the absolute magnitudes inferred from direct transformation of the TGAS parallaxes; (ii) adopting astrometry-based luminosities; and (iii) using a Bayesian fitting approach. The last two methods work in parallax space where parallaxes are used directly, thus maintaining symmetrical errors and allowing negative parallaxes to be used. The TGAS-based PL,PW,PLZ, and M V - [Fe/H] relations are discussed by comparing the distance to the Large Magellanic Cloud provided by different types of pulsating stars and alternative fitting methods. Results. Good agreement is found from direct comparison of the parallaxes of RR Lyrae stars for which both TGAS and HST measurements are available. Similarly, very good agreement is found between the TGAS values and the parallaxes inferred from the absolute magnitudes of Cepheids and RR Lyrae stars analysed with the Baade-Wesselink method. TGAS values also compare favourably with the parallaxes inferred by theoretical model fitting of the multi-band light curves for two of the three classical Cepheids and one RR Lyrae star, which were analysed with this technique in our samples. The K-band PL relations show the significant improvement of the TGAS parallaxes for Cepheids and RR Lyrae stars with respect to the Hipparcos measurements. This is particularly true for the RR Lyrae stars for which improvement in quality and statistics is impressive. Conclusions. TGAS parallaxes bring a significant added value to the previous Hipparcos estimates. The relations presented in this paper represent the first Gaia-calibrated relations and form a work-in-progress milestone report in the wait for Gaia-only parallaxes of which a first solution will become available with Gaia Data Release 2 (DR2) in 2018. © ESO, 2017