Hard photon production and matrix-element parton-shower merging

We present a Monte-Carlo approach to prompt-photon production, where photons and QCD partons are treated democratically. The photon fragmentation function is modelled by an interleaved QCD+QED parton shower. This known technique is improved by including higher-order real-emission matrix elements. To this end, we extend a recently proposed algorithm for merging matrix elements and truncated parton showers. We exemplify the quality of the Monte-Carlo predictions by comparing them to measurements of the photon fragmentation function at LEP and to measurements of prompt photon and diphoton production from the Tevatron experiments.Comment: 18 pages, 5 figures, revised version with minor update

Anerkennung und ordre public: am Beispiel der Vollstreckungshilfe bei freiheitsentziehenden Sanktionen im Raum der Freiheit, der Sicherheit und des Rechts

Vollstreckungshilfe bedeutet die Vollstreckung einer freiheitsentziehenden Sanktion, die ein Staat nach seinen materiellen und prozessualen Regeln getroffen hat, durch einen anderen Staat nach dessen Vollstreckungs- und Vollzugsregeln. Sie beinhaltet damit die umfassendste Anerkennung strafrechtlicher Wertentscheidungen zwischen den Mitgliedstaaten der EU. Vollstreckungshilfe droht zugleich, die Dauer der tatsächlichen Strafverbüßung systemwidrig zu beeinflussen. Die Grenzen einer solchen zulässigen Beeinflussung werden herausgearbeitet. Der Verfasser kommt zu dem Schluss, dass eine vollständige Harmonisierung der Wertentscheidungen des materiellen Strafrechts durch die Union beim jetzigen Stand der Integration nicht möglich ist. Der Verfasser leitet daher systemkohärent zum Binnenmarktrecht und zu der ziviljustitiellen Zusammenarbeit aus Art. 67 Abs. 1, 2. Hs. AEUV einen unionsrechtlich kontrollierten nationalen $aordre public$z als Grenze des Grundsatzes der gegenseitigen Anerkennung ab.»Mutual Recognition and Ordre Public Taken the Example of Transnational Enforcement of Custodial Sanctions in the Area of Freedom, Security, and Justice«The transnational enforcement of custodial sanctions within the EU implies the utmost mutual recognition of value decision established by criminal justice systems of the EU Member States. The study evaluates the legal framework of this type of mutual legal assistance, as well as its limits. It comes to the conclusion that the principle of mutual recognition needs to be limited by a reservation of national ordre public a limitation to be derived from Art 67 § 1 TFEU

Calibrating the Nelson–Siegel–Svensson model

The Nelson–Siegel–Svensson model is widely-used for modelling the yield curve, yet many authors have reported ‘numerical difficulties’ when calibrating the model. We argue that the problem is twofold: firstly, the optimisation problem is not convex and has multiple local optima. Hence standard methods that are readily available in statistical packages are not appropriate. We implement and test an optimisation heuristic, Differential Evolution, and show that it is capable of reliably solving the model. Secondly, we also stress that in certain ranges of the parameters, the model is badly conditioned, thus estimated parameters are unstable given small perturbations of the data. We discuss to what extent these difficulties affect applications of the model.

Mapping Tasks to Interactions for Graph Exploration and Graph Editing on Interactive Surfaces

Graph exploration and editing are still mostly considered independently and systems to work with are not designed for todays interactive surfaces like smartphones, tablets or tabletops. When developing a system for those modern devices that supports both graph exploration and graph editing, it is necessary to 1) identify what basic tasks need to be supported, 2) what interactions can be used, and 3) how to map these tasks and interactions. This technical report provides a list of basic interaction tasks for graph exploration and editing as a result of an extensive system review. Moreover, different interaction modalities of interactive surfaces are reviewed according to their interaction vocabulary and further degrees of freedom that can be used to make interactions distinguishable are discussed. Beyond the scope of graph exploration and editing, we provide an approach for finding and evaluating a mapping from tasks to interactions, that is generally applicable. Thus, this work acts as a guideline for developing a system for graph exploration and editing that is specifically designed for interactive surfaces.Comment: 21 pages, minor corrections (typos etc.

OpenID as an Approach for User-centric Identity Management

Nowadays, users are confronted with a number of different passwords and accounts in the Internet, resulting in a complex and time-consuming identity management. OpenID as an approach for a user-centric identity management is supposed to reduce the user’s effort. This paper analyses how OpenID can be used as an identity management solution in the Internet and to what extent it matches the idea of a user-centric identity. On the basis of a study, we show general limitations of OpenID and specific challenges regarding the user-centricity. At the end, we point out open research questions and further developments in this area

Matching Parton Showers and Matrix Elements

We compare different procedures for combining fixed-order tree-level matrix element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW scheme and one based on the so-called MLM scheme using different matrix element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences.Comment: Proceedings of the "HERA and the LHC" workshop, CERN/DESY 2004/200

Do undersowings in maize influence the development of larvae of the western corn rootworm?

Beeinflussen Untersaaten in Mais die Entwicklung der Larven des Westlichen Maiswurzelbohrers