Risk management with regard to dioxin residues in pork meat

Maximum levels for dioxins have been established in 2001 in feed (feed materials and compound feed) and food of animal origin (fish, meat, eggs, milk and derived products). They are in force since 1 January 2002. These maximum levels were complemented in 2006 with maximum levels for the sum of dioxins and dioxin-like PCBs in feed and food. By the Regulation (EC) No 183/2005 of the European Parliament and of the Council of 12 January 2005 feed business operators have to put in place, implement and maintain procedures based on the Hazard Analysis Critical Control Points (HACCP) principles. This means the identification of critical control points and the identification of, inter alia, possible chemical contamination

On arrangements of hyperplanes from connected subgraphs

We investigate arrangements of hyperplanes whose normal vectors are given by connected subgraphs of a fixed graph. These include the resonance arrangement and certain ideal subarrangements of Weyl arrangements. We characterize those which are free, simplicial, factored, or supersolvable. In particular, such an arrangement is free if and only if the graph is a cycle, a path, an almost path, or a path with a triangle attached to it.Comment: 22 pages, 7 figures, minor edit

A Massively Parallel Algorithm for the Approximate Calculation of Inverse p-th Roots of Large Sparse Matrices

We present the submatrix method, a highly parallelizable method for the approximate calculation of inverse p-th roots of large sparse symmetric matrices which are required in different scientific applications. We follow the idea of Approximate Computing, allowing imprecision in the final result in order to be able to utilize the sparsity of the input matrix and to allow massively parallel execution. For an n x n matrix, the proposed algorithm allows to distribute the calculations over n nodes with only little communication overhead. The approximate result matrix exhibits the same sparsity pattern as the input matrix, allowing for efficient reuse of allocated data structures. We evaluate the algorithm with respect to the error that it introduces into calculated results, as well as its performance and scalability. We demonstrate that the error is relatively limited for well-conditioned matrices and that results are still valuable for error-resilient applications like preconditioning even for ill-conditioned matrices. We discuss the execution time and scaling of the algorithm on a theoretical level and present a distributed implementation of the algorithm using MPI and OpenMP. We demonstrate the scalability of this implementation by running it on a high-performance compute cluster comprised of 1024 CPU cores, showing a speedup of 665x compared to single-threaded execution

What a MESS: Multi-Domain Evaluation of Zero-Shot Semantic Segmentation

While semantic segmentation has seen tremendous improvements in the past, there is still significant labeling efforts necessary and the problem of limited generalization to classes that have not been present during training. To address this problem, zero-shot semantic segmentation makes use of large self-supervised vision-language models, allowing zero-shot transfer to unseen classes. In this work, we build a benchmark for Multi-domain Evaluation of Semantic Segmentation (MESS), which allows a holistic analysis of performance across a wide range of domain-specific datasets such as medicine, engineering, earth monitoring, biology, and agriculture. To do this, we reviewed 120 datasets, developed a taxonomy, and classified the datasets according to the developed taxonomy. We select a representative subset consisting of 22 datasets and propose it as the MESS benchmark. We evaluate eight recently published models on the proposed MESS benchmark and analyze characteristics for the performance of zero-shot transfer models. The toolkit is available at https://github.com/blumenstiel/MESS

Mobiltelefonerfahrung und Antwortqualität bei Umfragen

"Telefonische Befragungen über das Mobilfunknetz sind inzwischen ein Bestandteil der sozialwissenschaftlichen Datengewinnung. Da es sich beim Mobilfunk jedoch noch um eine relativ junge Befragungstechnologie handelt, stellt sich die Frage, inwieweit die Routine im Umgang mit dem Handy als eine Determinante der Antwortqualität wirkt. Dieser Frage wurde im Rahmen des Projektes CELLA nachgegangen (Telefonbefragungen in der Allgemeinbevölkerung über das Mobilfunknetz 2009, GESIS Köln, Deutschland, DOI: 10.4232/1.4875). CELLA wurde durch die Deutsche Forschungsgemeinschaft gefördert und steht für telefonische Befragungen via Mobilfunk (CELl phone) und via Festnetz (LAndline phone). Zunächst werden die Operationalisierung und die Bildung eines Index beschrieben, anhand dessen die Routine im Umgang mit dem Mobilfunk gemessen werden kann. Auf der Basis von sechs Kriterien der Antwortqualität wird dann nach den entsprechenden Zusammenhängen gesucht. Dabei stellt sich heraus, dass sich - entgegen unseren ursprünglichen Erwartungen - solche Zusammenhänge jedoch kaum nachweisen lassen. Die Befunde sind für den Einsatz von telefonischen Befragungen über das Mobilfunknetz insgesamt positiv zu bewerten. Sie verdienen es aber auch, bei der Diskussion um die Determinanten der Antwortqualität bei Umfragen allgemein berücksichtigt zu werden. So zeigt sich vor allem, dass von einer ganzen Reihe an Determinanten ein stärkerer Einfluss auf die Antwortqualität ausgeht als von der Routine." (Autorenreferat)"Telephone surveys via mobile phones have become increasingly important for the social sciences. The use of mobile phones in interviews is still a novelty. Thus the question arises to what extent the respondents' experience with mobile phones influences the response quality. The German Research Foundation funded a CELLA project to investigate how to conduct mobile phone surveys. CELLA stands for CELl phone and LAndline phone surveys. Technische Universität Dresden, Germany, and GESIS - Leibniz Institute for Social Sciences, Germany, cooperated for that purpose. Data presented in the following section were collected within the frame of CELLA (Telefonbefragungen in der Allgemeinbevölkerung über das Mobilfunknetz 2009, GESIS Köln, DOI: 10.4232/1.4875). Firstly, an index for the experience in handling mobile phones is presented. This is followed by an examination of correlations between the index and six aspects of response quality. A significant influence of the experience was - against our expectations - not found. The results support the conduct of telephone surveys via mobile phones. Nevertheless, there are numerous determinants with stronger influence, which suggests that further research needs to be done." (author's abstract