Cayley-Bacharach Formulas

The Cayley-Bacharach Theorem states that all cubic curves through eight given points in the plane also pass through a unique ninth point. We write that point as an explicit rational function in the other eight.Comment: 13 pages, 4 figure

International-vergleichende Analyse regionaler Schulentwicklung: Yorkshire und Westfalen

In dem Artikel werden ausgewählte empirische Befunde aus zwei Forschungsprojekten integriert, um den möglichen Ertrag einer international-vergleichenden Analyse regionaler Schulentwicklung für die Vergleichende Erziehungswissenschaft auszuloten. Mit diesem Ziel werden amtliche Daten zu den allgemein bildenden Sekundarschulen in zwei englischen (York und Bradford) und zwei deutschen (Münster und Bochum) Großstädten in Tabellen systematisiert und in zwei Schritten ausgewertet: Es wird gezeigt, dass das Schulrecht in England und Nordrhein-Westfalen ein breites Spektrum von Prinzipien und Instrumenten der Schulgliederung eröffnet, das in jeder Stadt zur Entwicklung von ortsspezifischen und sehr differenzierten Schulangebotstrukturen geführt hat. Die Daten zur sozialräumlichen Vernetzung der Schulen geben darüber hinaus eine inoffizielle Typologie von Schulen zu erkennen, die andere Dimensionen der schulischen Profilbildung ergänzen oder überlagern. Abschließend werden die Ergebnisse der empirischen Analyse im Kontext aktueller wissenschaftlicher und bildungspolitischer Debatten diskutiert. (DIPF/Orig.)The authors integrate selected empirical findings from two research projects in order to assess the usefulness of an international comparative analysis of regional school development for comparative educational science. Official data on general secondary schools in two English (York and Bradford) and two German (Muenster and Bochum) cities are systematized in tables and evaluated in two steps: it is shown that school regulations in both England and North Rhine-Westphalia offer a broad spectrum of principles and instruments for a subdivision into different school types, which has led to the development of region-specific and highly differentiated structures of schooling in each of these cities. Furthermore, data on the interconnection between individual schools based upon regional social conditions reveals an inofficial typology of schools which supplements or overrides other dimensions of a school\u27s profile development. Finally, the results of the empirical analysis are discussed within the context of recent debates on educational science and politics. (DIPF/Orig.

On the McLafferty Rearrangement of Ionized Phenyl Pyridyl Alkanones

A detailed investigation concerning the genesis of McLafferty rearrangement products from molecular ions of phenyl pyridyl alkanones reveals the following features: 1) The various products are not formed by competitive dissociations of the molecular ion. Most of the relevant fragment ions are generated from the primary McLafferty product of a hydrogen transfer to the ionized carbonyl group (M+·→m/z 163, ion k). The ion k plays a decisive role for the generation of the abundant product ions at m/z 93 (ion g) and m/z 106 (ion s) both of which are formed by further dissociation of k. Details of the mechanisms for the decomposition of k are obtained by investigating [D]-labelled isotopomers, the analysis of low and high resolution data, the application of MIKE and CA spectra. The problem of keto/enol tautomerism between some ions, relevant in this context, is discussed and it is shown that these isomerization processes are not involved. A detailed description is given for the syntheses of various [D]-labelled phenyl pyridyl alkanones

Railway Timetabling Based on Systematic Follow-up on Realized Railway Operations

This paper shows that the use of systematic follow-up on realized railway operations has potential to improve current and future timetables. After describing the present timetabling process at the main Danish Infrastructure Manager, Rail Net Denmark, it is concluded that systematic follow-up on realized railway operations is not yet a formal integrated part of the timetabling process. As Rail Net Denmark uses timetabling guidelines from the European professional organization of infrastructure managers - Rail Net Europe – the lack of systematic follow-up may very well exist elsewhere in Europe. Following the introduction, an initial theoretical approach to systematic follow-up on realized operations is described. Focus is on identifying delay patterns in regards to individual train numbers, train categories, time periods and geography or combinations hereof. Subsequently theory is put into practice. First, the current system for collecting data on operational performance is described as well as methods on how to aggregate this. Six chosen cases are examined to cover the four focus points and combinations hereof. Detailed results are shown in Appendices 1-6. The analyses prove existing ideas about delay patterns in today’s railway operations. Finally it can be concluded that the timetabling process at Rail Net Denmark has a potential for improvements by integrating systematic follow-up on realized operations in the process. By introducing closer cooperation between timetabling and operations monitoring specialists regarding systematic analyses throughout the entire timetabling process there is a potential to improve valid and future timetables

Traceability of Chemical Measurement Results

Traceability to recognised references, ultimately to the SI units, is an indispensable prerequisite for measurement results to be comparable and trustworthy and hence accepted worldwide. This holds also for chemical measurement results, particularly as these are often used as a basis for important decisions and agreements, for example in health care and environmental protection. The concept of traceability and the special problems associated with its application to chemical analysis as compared to metrology in general are described. Current approaches to establish traceability of chemical measurement results are reported. The most important development in the last two decades was the establishment of the Consultative Committee for Metrology in Chemistry under the Metre Convention, which provided the basis for an international reference framework for chemical measurements. In order to link up laboratory results anywhere in the world with this international reference framework, traceability structures on the national level are required. It is shown, using the demand for traceable chemical measurements in Germany as an example, how such structures can be established and efficiently used

The ESARDA Working Group on Containment and Surveillance: Activities and achievements

The working group on containment and surveillance (C/S) is one of the discipline-oriented working groups of ESARDA ¿ the European Safeguards Research and Development Association. Its mission is (a) to provide the safeguards community with expert advice on C/S instruments and methods and on their performance and (b) to act as a forum for the exchange of information on such instruments and methods, including unattended and remote monitoring systems. Currently, sixteen institutions contribute to the working group as members or observers. The institutions represent safeguards authorities including the European Commission¿s Directorate General for Energy (in charge of the implementation of the EURATOM treaty) and the International Atomic Energy Agency (IAEA), instrument developers, plant operators, national authorities and research laboratories. The working group meets twice per year, in order to address and discuss topics of interest. To this end, individual working group members volunteer to prepare discussion and working papers. The goal is to publish the results of the working group¿s discussions, preferably in the ESARDA Bulletin. The working group¿s current topics include: (i) Guidelines for developing sealing systems; (ii) XCam: IAEA¿s Next Generation Surveillance System; (iii) Interface between Safeguards and Security; (iv) 3D Laser based applications in Safeguards; (v) New generation of sealing developments; (vi) Enhanced Data Authentication System; (vii) Designing and simulating tools for surveillance and remote monitoring, and (viii) Performance & assurance of C/S instrumentation. For the ESARDA web site, the working group maintains a compendium of C/S instruments and methods and contributes to drafting technical sheets on safeguards-specific topics. When appropriate, the working group holds joint meetings with other ESARDA working groups to discuss topics of common interest. Regarding the annual ESARDA course on Nuclear Safeguards and Non-Proliferation, the working group provides a lecturer and material on C/S instrumentation and methods. The paper describes the working group¿s current terms of reference, membership, working method, topics of interest, achievements, and gives an outlook on the topics to be addressed in the near future.JRC.E.9-Nuclear security (Ispra

Der Anteil Transportwasser bei Heringsanlandungen mittels Vakuumsauganlage in Großraumbehältern

Estimation of the water content of herring landings caused by pressure-vacuum double tank pumps and using of multi purpose transport containers About 80 % of herring that is landed in the fish processing company Euro-Baltic Fischverarbeitungs GmbH Mukran, on the Isle of Rügen at the Baltic coast is transported from the cutter into the processing plant by pumping. For this purpose 700 l-Euro-size polyethylene tubs (containers) are filled with herring by means of a pressure-vacuum pump-systems during the unloading of the cutter. To be able to pump the fish from the hold on board it is kept floating in water (transport water). At the end of the pumping/transporting process the fish ends in a dewatering box before reaching the tub, where the transport water is separated from the fish. Then, the not completely dewatered fish is slipped into the transport containers. The amount of transport water reaching the containers depends on the type of PV-equipment and on the amount of transport water in the fish holds of the different cutters. Methodologically the mixture of fish and water must be weighed together. For the experiments specially designed transport container were used which allow the measurement of the run-off of the water to be quantified and thus to measure the proportion of water remaining with the fish. Based on 30 experiments it could be shown that on average 6 % of remaining weight of the mixture is water. Furthermore, factors were detected which influence the variability of the proportion of water

Der Haftwasseranteil bei Heringsanlandungen über Bandwaagen

In 2004 the fish processing company Euro-Baltic Fischverarbeitungs GmbH Mukran, went into operation on the Isle of Rügen at the Baltic coast of Germany. About 20 % of the herring landed there is discharged from the cutters into the processing plant by pipes, driven by pumps, in case that the landed volume exceeds 10 t fresh weight. In such case the herring is transported in water suspension by means of a pressure-vacuum suction pump system into containers and further transported via conveyer belt to a flowscale. During this process most of the water runs off. It is however unknown how much water remains with the fish and is eventually weighted as fish. To estimate this proportion the mixture of water and fish was stored in special transport containers, which allow the measurement of the run-off. As a result the study shows that on average 2 % of weight measured by the tape scale is water. Along with this factors were determined which influence the variability of the proportion of water