Robust designs in non-inferiority three arm clinical trials with presence of heteroscedasticity

In this paper, we describe an adjusted method to facilitate a non-inferiority trial by a three-arm robust design. Because local optimal designs derived in Hasler et al. [2007] require knowledge about the ratios of the population variances and are not necessarily robust with respect to possible misspecifications, a maximin approach is adopted. This method requires only the specification of an interval for the of variance ratios and yields robust and efficient designs. We demonstrate that a maximin optimal design only depends on the boundary points specified for the intervals of the variance ratios and receive numerical and analytical solutions. The derived designs are robust and very efficient for statistical analysis in non inferiority three arm trials. --maximin design,robust design,non-inferiority,three arm design,gold design trials,randomized clinical trial

Exploiting technological synergies for future launch vehicles

Two launch vehicle concepts based on technologies available today or in a short term future in Western Europe are presented. The design of both launchers has the goal of exploiting synergies with current European programs to limit development and operational costs. Technologies of particular interest here are the high performance solid rocket motors with carbon-epoxy filament wound monolithic motor cases and the future high performance cryogenic expander cycle engine Vinci. The first concept dubbed ANGELA (A New GEneration LAuncher) is a study financed with funds of the German Ministry of Economics and managed by the DLR Space Administration. The project, which started in the summer of 2012 aims at designing a low cost versatile launcher able to place payloads between 2 and 5 tons into GTO. Three architectures have been considered during the first phase of the study. This phase was concluded in March 2013 with the preliminary stagings, which will be the starting point of more detailed analyses. The first architecture is made out of an H110 (stage with 110 tons of LOx/LH2) equipped with two Vulcain 2 engines with shortened nozzles and an H29 propelled by a Vinci engine. In addition the variation of the number of P36 solid rocket boosters allow to reach the entire range of payload performance. The second architecture differs from the first one only by the use of a new staged-combustion engine instead of two Vulcain 2 engines. The new engine, which should deliver 1800 kN in vacuum, allows a reduction of the size of the stages to H90-H24, enhanced with P34 boosters. The third and last architecture is a so called Multi PPH. The first stage is a bundle of 2 or 3 P120 solid rocket motors. The second stage is made out of one single P120, strictly similar to those used for the first stage. Finally the upper stage is an H23 equipped with a Vinci engine, the same as the two other architectures. The second launcher concept described in this paper is the small TSTO launch vehicle. It consists of a large solid rocket motor first stage P175 and a cryogenic upper stage propelled by the Vinci engine, H26. The preliminary design performed at DLR-SART considers two target performances. The light version of the small TSTO shall perform Galileo satellite replacement single launch missions to MTO corresponding to a payload performance of about 1400 kg in GTO. A heavy version of the launch vehicle shall be able to launch payloads up to 3000 kg in GTO. The performance increase for the heavy version is made possible by the addition of two pairs of P23 boosters, the second pair being ignited with a delay

Heterogeneity in the Evaluation of Quality Assurance Systems: The International Food Standard (IFS) in European Agribusiness

Due to the growing demands of customers and several food crises, quality assurance schemes have become increasingly popular in agribusiness. With this trend in mind, it seems worthwhile to take a closer look at the satisfaction of participating European companies. The study focuses on the IFS, which has gained much relevance in the food industry. A questionnaire concerned with perceptions of the advantages and disadvantages of the IFS was answered by 389 companies. The results indicate that the overall evaluation of the IFS is primarily affected by the perceived usefulness of the catalogue of requirements and its evaluation. Furthermore, a cluster analysis was conducted and three clusters were identified, representing heterogeneous evaluations of the IFS.evaluation, quality assurance systems, International Food Standard, agribusiness, Agribusiness, Food Consumption/Nutrition/Food Safety, Q10, Q13, Q18,

Regionalwirtschaftliche Effekte veränderter Wassernutzung in Nordost-Niedersachsen

Mit der Wasserrahmenrichtlinie hat die EU einen juristischen Rahmen geschaffen, alle aquatischen Ökosysteme, zu denen auch die Grundwasserkörper gehören, zu schützen. Diese vornehmlich auf den Wasserschutz abzielende Maßnahme zieht neben klaren Vorteilen für den Wasserhaushalt und die -versorger möglicherweise auch Vor- wie Nachteile für landwirtschaftliche Betriebe wie landwirtschaftlich geprägte Regionen nach sich. Mit dem vorliegenden Beitrag wird untersucht, welche regionalen Effekte eine verminderte Beregnung für eine der am stärksten von Trockenheit betroffenen Regionen Nordostniedersachsen besitzen würde. Mit Hilfe des Regionalmodels „POMMARD“ wurden die regionalen Effekte (a) einer Halbierung des verfügbaren Beregnungswassers sowie (b) eines vollständigen Verzichts auf Beregnung projiziert. Die Ergebnisse zeigen, dass eine Beschränkung der Wasserentnahmeerlaubnisse schwach negative Konsequenzen für die Region besitzt. Der vollständige Verzicht auf Beregnung dagegen hat deutliche Auswirkungen sowohl auf den Agrarsektor als auch auf die regionale Entwicklung. Die Wasserrahmenrichtlinie kann deshalb bei sachgerechter Festlegung der Entnahmemengen für Feldberegnung als eine Möglichkeit gesehen werden, die Wassernutzungseffizienz zu erhöhen und gleichzeitig natürliche Ressourcen zu schonen.Feldberegnung, Input-Output Analyse, Systemdynamiken, Regionale Wirtschaftskreisläufe, Environmental Economics and Policy,

High-level expression of a viscotoxin in Arabidopsis thaliana gives enhanced resistance against Plasmodiophora brassicae

Viscotoxins are a group of toxic thionins found in several mistletoe species. The constitutive CaMV-Ω promoter was used to drive the expression of the viscotoxin A3 cDNA from Viscum album in transgenic Arabidopsis thaliana C24. Lines with high viscotoxin A3 levels in all parts of the plant were selected and tested for resistance against the clubroot pathogen Plasmodiophora brassicae. The transgenic lines were more resistant to infection by this pathogen than the parental lin

The need for improved management of the subsurface

The subsurface is used intensively to support economic stability and growth. Human interaction with the shallow subsurface ranges from exploitation of resources, accommodation of utilities, harnessing of energy (ground source heat pumps) and storage of waste. Current practice of managing these shallow subsurface zones is far from ideal. Many subsurface interventions are preceded by feasibility studies, predictive models or investigative measures to mitigate risks or predict the impacts of the work. However, the complex interactions between the anthropogenic structures and natural processes mean that a holistic impact assessment is often not achievable. By integrating these subsurface infrastructures within three dimensional framework models, a comprehensive assessment of the potential hazards in these shallow subsurface environments may be made. Some Geological Survey Organizations (GSOs) are currently developing subsurface management systems that will aid decision making in the shallow subsurface [1]. The British Geological Survey (BGS) is developing an open Environmental Modeling Platform [2] to provide the data standards and applications to link models, numerical simulations and ultimately socio-economic models so as to generate predictive responses to questions concerning sustainable us of the subsurface

ROS - To Live and let die

Reactive oxygen species (ROS) are central factors in a couple of plant stress responses. Their role is ambiguous - they can occur as manifestation of stress-dependent damage, but they also play an important role as signals that transduce a stress situation and are important for the activation of adaptive responses

Evaluation von Maßnahmen der postoperativen Versorgung von Patienten mit vorderen Kreuzbandrupturen unter sportwissenschaftlichen Gesichtspunkten

Ausgehend von steigenden Kosten im Gesundheitssystem sollen zwei ambulante Rehabilitationsverfahren bei Patienten mit operativ versorgter vorderer Kreuzbandruptur hinsichtlich ihrer therapeutischen und ökonomischen Effizienz evaluiert werden. Als Rehabilitationsmethoden werden in dieser Arbeit die Erweitere Ambulante Physiotherapie und eine rein krankengymnastische Therapieform miteinander verglichen. Hierzu wurde ein Untersuchungsinstrumentarium entwickelt, welches als zentrales Element die Ganganalyse beinhaltet. Mit Hilfe der Ganganalyse werden Kinematik, Kinetik und elektromyographische Muskelsignale der Patienten erfaßt. Weitere Untersuchungsschwerpunkte bilden die Atemgasanalyse, die Isokinetik und die Erfassung der subjektiven Funktionalitäts- und Stabilitätsscores. Anhand der insgesamt einjährigen Betrachtungszeit kann zum einen die wissenschaftliche und therapeutische Eignung des Untersuchungsinstrumentariums evaluiert werden, zum anderen ist es möglich, die therapeutische Effizienz der vorgestellten Therapien zu beurteilen. Die Ergebnisse werden in einen ökonomischen Kontext gestellt

Investigation of the membrane localization and distribution of flavonoids by high-resolution magic angle spinning NMR spectroscopy

AbstractTo investigate the structural basis for the antioxidative effects of plant flavonoids on the lipid molecules of cellular membranes, we have studied the location and distribution of five different flavonoid molecules (flavone, chrysin, luteolin, myricetin, and luteolin-7-glucoside) with varying polarity in monounsaturated model membranes. The investigated molecules differed in the number of hydroxyl groups attached to the polyphenolic benzo-γ-pyrone compounds. To investigate the relation between hydrophobicity and membrane localization/orientation, we have applied 1H magic angle spinning NMR techniques measuring ring current induced chemical shift changes, nuclear Overhauser enhancement cross-relaxation rates, and lateral diffusion coefficients. All investigated flavonoids show a broad distribution along the membrane normal with a maximum in the lipid/water interface. With increasing number of hydroxyl groups, the maximum of this distribution is biased towards the lipid headgroups. These results are confirmed by pulsed field gradient NMR measurements of the lateral diffusion coefficients of phospholipids and flavonoids, respectively. From the localization of different flavonoid protons in the membrane, a model for the orientation of the molecules in a lipid bilayer can be deduced. This orientation depends on the position of the polar center of the flavonoid molecule