A Note on Queueing Systems Exposed to Disasters

We discuss queueing systems subject to total disasters. If the time intervals between successive disasters are i.i.d. random variables independent of arrival and service process and arrivals form a Poisson process, then the transient and the asymptotic analysis of such models may be based on Feller's Second Renewal Theorem. Several examples are given: the limiting behavior of M/G/1 in case of exponential disasters and its special cases M/M/1, M/M/1/K and M/M/infinity. (author´s abstract)Series: Research Report Series / Department of Statistics and Mathematic

Lattice path counting and the theory of queues

In this paper we will show how recent advances in the combinatorics of lattice paths can be applied to solve interesting and nontrivial problems in the theory of queues. The problems we discuss range from classical ones like M^a/M^b/1 systems to open tandem systems with and without global blocking and to queueing models that are related to random walks in a quarter plane like the Flatto-Hahn model or systems with preemptive priorities. (author´s abstract)Series: Research Report Series / Department of Statistics and Mathematic

A transient Analysis of M/G/1 Queues with N-policy

We consider an M/G/1 queueing model with N-policy operating. This means, that the server will start up only if a queue of a prescribed length has built up. For this model the time dependent distribution of the queue lenght is given by simple renewal arguments without resorting to integral transform techniques. (author's abstract)Series: Forschungsberichte / Institut für Statisti

Empirical Evaluation of Semi-automated XML Annotation of Text Documents with the GoldenGATE Editor

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Tarifabschluss im öffentlichen Dienst - die große Tarifrechtsreform?

Stellt der Tarifabschluss für Arbeiter und Angestellte von Bund und Kommunen einen Beitrag zum Einstieg in eine umfassende Neustrukturierung des öffentlichen Dienstes dar, oder wurde vor allem an den bisherigen alten Strukturen des öffentlichen Dienstes festgehalten? Für Dr. Thomas Böhle, Vereinigung der Kommunalen Arbeitgeberverbände, wird "das bisherige Tarifrecht … durch ein modernes, leistungsorientiertes und transparentes Tarifrecht ersetzt, das den Anforderungen einer modernen Verwaltung für die Bürgerinnen und Bürger gerecht wird". Auch Dr. Ralf Stegner, Finanzminister des Landes Schleswig-Holstein, sieht positive Elemente: "Der Potsdamer Tarifabschluss vom 9. Februar 2005 ist der erste Baustein zur großen Tarifrechtsreform durch Einführung einer neuen Entgeltordnung, in dem auch die Gewerkschaften durchaus ihre Reformfähigkeit unter Beweis gestellt haben.… Im Detail gibt es aus Ländersicht aber auch kritisch zu hinterfragende Entscheidungen." Weitaus skeptischer ist Prof. Dr. Walter A. Oechsler, Universität Mannheim: "Die Analyse macht deutlich, dass die Tarifreform nicht die große durchgreifende Modernisierung des Tarifrechts im öffentlichen Dienst darstellt." Nach Ansicht von Prof. Dr. Monika Böhm, Universität Marburg, stellt der Tarifvertrag einen wichtigen Beitrag zum Einstieg in eine umfassend erforderliche Neustrukturierung des öffentlichen Dienstes dar, obwohl weitgehend an den bisherigen Strukturen festgehalten wurde.Öffentlicher Dienst, Angestellte, Arbeiter, Tariflohn, Leistungsorientierte Vergütung, Tarifvertrag, Deutschland

Regional climate model simulations as input for hydrological applications: evaluation of uncertainties

International audienceThe ERA15 Reanalysis (1979-1993) has been dynamically downscaled over Central Europe using 4 different regional climate models. The regional simulations were analysed with respect to 2m temperature and total precipitation, the main input parameters for hydrological applications. Model results were validated against three reference data sets (ERA15, CRU, DWD) and uncertainty ranges were derived. For mean annual 2 m temperature over Germany, the simulation bias lies between -1.1°C and +0.9°C depending on the combination of model and reference data set. The bias of mean annual precipitation varies between -31 and +108 mm/year. Differences between RCM results are of the same magnitude as differences between the reference data sets

Structural manipulations of a shelter resource reveal underlying preference functions in a shell-dwelling cichlid fish

Many animals can modify the environments in which they live, thereby changing the selection pressures they experience. A common example of such niche construction is the use, creation or modification of environmental resources for use as nests or shelters. Because these resources often have correlated structural elements, it can be difficult to disentangle the relative contribution of these elements to resource choice, and the preference functions underlying niche-construction behaviour remain hidden. Here, we present an experimental paradigm that uses 3D scanning, modelling and printing to create replicas of structures that differ with respect to key structural attributes. We show that a niche-constructing, shell-dwelling cichlid fish,; Neolamprologus multifasciatus; , has strong open-ended preference functions for exaggerated shell replicas. Fish preferred shells that were fully intact and either enlarged, lengthened or had widened apertures. Shell intactness was the most important structural attribute, followed by shell length, then aperture width. We disentangle the relative roles of different shell attributes, which are tightly correlated in the wild, but nevertheless differentially influence shelter choice and therefore niche construction in this species. We highlight the broad utility of our approach when compared with more traditional methods (e.g. two-choice tasks) for studying animal decision-making in a range of contexts

Kinematic modelling of disk galaxies I. A new method to fit tilted rings to data cubes

This is the first of a series of papers in which the kinematics of disk galaxies over a range of scales is scrutinised employing spectroscopy. A fundamental aspect of these studies is presented here: the new publicly available software tool TiRiFiC (http://www.astro.uni-bonn.de/~gjozsa/tirific.html) enables a direct fit of a ``tilted-ring model'' to spectroscopic data cubes. The algorithm generates model data cubes from the tilted-ring parametrisation of a rotating disk, which are automatically adjusted to reach an optimum fit via a chi-squared minimisation method to an observed data cube. The structure of the new software, the shortcomings of the previously available programs to produce a tilted-ring model, and the performance of TiRiFiC are discussed. Our method is less affected by the well-known problem of beam smearing that occurs when fitting to the velocity field. Since with our method we fit many data points in a data cube simultaneously, TiRiFiC is sensitive to very faint structures and can hence be used to derive tilted-ring models significantly extending in radius beyond those derived from a velocity field. The software is able to parametrise HI disks of galaxies that are intersected by the line-of-sight twice or more, i.e. if the disks are heavily warped, and/or with a significant shift of the projected centre of rotation, and/or if seen edge-on. Furthermore, our method delivers the surface-brightness profile of the examined galaxy in addition to the orientational parameters and the rotation curve. In order to derive kinematic and morphological models of disk galaxies, especially reliable rotation curves, a direct-fit method as implemented in our code should be the tool of choice.Comment: 37 pages, 24 figures. Accepted for publication in Astronomy and Astrophysic

Antisense Oligonucleotide- and CRISPR-Cas9-Mediated Rescue of mRNA Splicing for a Deep Intronic CLRN1 Mutation

Mutations in CLRN1 cause Usher syndrome (USH) type III (USH3A), a disease characterized by progressive hearing impairment, retinitis pigmentosa, and vestibular dysfunction. Due to the lack of appropriate disease models, no efficient therapy for retinitis pigmentosa in USH patients exists so far. In addition, given the yet undefined functional role and expression of the different CLRN1 splice isoforms in the retina, non-causative therapies such as gene supplementation are unsuitable at this stage. In this study, we focused on the recently identified deep intronic c.254-649T>G CLRN1 splicing mutation and aimed to establish two causative treatment approaches: CRISPR-Cas9-mediated excision of the mutated intronic region and antisense oligonucleotide (AON)-mediated correction of mRNA splicing. The therapeutic potential of these approaches was validated in different cell types transiently or stably expressing CLRN1 minigenes. Both approaches led to substantial correction of the splice defect. Surprisingly, however, no synergistic effect was detected when combining both methods. Finally, the injection of naked AONs into mice expressing the mutant CLRN1 minigene in the retina also led to a significant splice rescue. We propose that both AONs and CRISPR-Cas9 are suitable strategies to initiate advanced preclinical studies for treatment of USH3A patients

Nutritional Value of the Duckweed Species of the Genus Wolffia (Lemnaceae) as Human Food

Species of the genus Wolffia are traditionally used as human food in some of the Asian countries. Therefore, all 11 species of this genus, identified by molecular barcoding, were investigated for ingredients relevant to human nutrition. The total protein content varied between 20 and 30% of the freeze-dry weight, the starch content between 10 and 20%, the fat content between 1 and 5%, and the fiber content was ~25%. The essential amino acid content was higher or close to the requirements of preschool-aged children according to standards of the World Health Organization. The fat content was low, but the fraction of polyunsaturated fatty acids was above 60% of total fat and the content of n-3 polyunsaturated fatty acids was higher than that of n-6 polyunsaturated fatty acids in most species. The content of macro- and microelements (minerals) not only depended on the cultivation conditions but also on the genetic background of the species. This holds true also for the content of tocopherols, several carotenoids and phytosterols in different species and even intraspecific, clonal differences were detected in Wolffia globosa and Wolffia arrhiza. Thus, the selection of suitable clones for further applications is important. Due to the very fast growth and the highest yield in most of the nutrients, Wolffia microscopica has a high potential for practical applications in human nutrition