Bøger udgivet af Cuvillier

Fagus sylvatica is one of the most important tree species in Europe. Due to its extensive distributionand dominance in its range, the performance of European forests in the contexts of perceivedclimate change will largely depend on the reaction of beech forests. Adequate informationabout the genetic diversity and structure of the species is indispensable for the conservation andsustainable utilization of the forests. Forest management systems currently in use in Germany areconsidered sustainable. However, their impact on the genetic diversity and spatial genetic structureof F. sylvatica is largely unknown. In these contexts, the main objectives of this dissertationwere a) to assess the genetic diversity and differentiation of F. sylvatica at different spatialscales, b) to determine the level and magnitude of fine-scale genetic structure of the beechstands, c) to investigate the effect of forest management activities on the genetic diversity andfine-scale genetic structure of the beech stands independent of the marker used and d) to comparemicrosatellite and AFLP markers to estimate genetic diversity and structure of the stands,and their applicability to detect management impacts on genetic structure of the stand.

The automatic verification of computer programs is an important step in software engineering. In this regard temporal logics have been invented as an extension of modal logic which itself is an extension of propositional logic. Therefore, one may call them \emph{modal logic variants}.The first part of this thesis will investigate the two temporal logics CTL and CTL* with respect to their model-checking and satisfiability problem. We will analyze the complexity of fragments of these problems by means of operator and Boolean function restrictions. There we will see for the satisfiability problem, how the operator fragments form a trichotomy and the Boolean fragments form a quartering. The model-checking problem for CTL is divided into three types: monotone, atomic negation, and positive fragments. Surprisingly, we will see that these three fragments are computationally equivalent. Furthermore, several prominent extensions of CTL will be visited and classified with respect to their Boolean and operator fragments.In the second part we will concentrate on description logics which are modal logic extensions settled in the area of semantic web, databases, and artificial intelligence. These types of logics are used to express, and work on, large sets of data. Besides the usual satisfiability problems, we will work with some special kind of implication problem, which is called subsumption. We will see that these logics combine two very strong Boolean concepts, namely implication and conjunction, such that restricting large sets of Boolean functions do not reduce the complexity of the problems significantly.

People use talk in marked and varied ways to make sense of the world. This has constituted one ofthe major themes in humanistic and social scientific thought since the mid-twentieth century. Thisbook discusses the defining elements of the study of these themes (Discourse Analysis), throwsmore light on the narrative discourse showing its implications on the pedagogic role of translation.The major interest of this study lies in the belief that mere descriptive accounts of sentencesare insufficient in connected discourse. One needs to go beyond the surface realisation in order toattain the intended meaning. Thus, it is not enough to describe the internal structure of the elementsin a sentence or a discourse; the ¿why¿ and the ¿where¿ these elements should be used is equallyimportant. It is for this reason that the study draws from Functional Grammar and Relevancetheoretical frameworks to identify and characterize the constituents of the Nweh narrative genre andto portray the relevance of such a study in Discourse Analysis to translation, both as a discipline andas a pedagogic tool in Second Language Acquisition contexts.It is hoped that language teachers and translators will use the suggestions in this book toameliorate their performances.This study challenges Nweh speakers to work towards the standardization and developmentof the Nweh Language and invites other scholars to continue to promote research in Africanlanguages at large and Cameroon national languages in particular. It is through such commitmentthat the much-needed preservation of Cameroon¿s multilingual heritage can be achieved.Professor Gabriel Mba

European beech (Fagus sylvatica L.) is the dominant tree species of the potential natural vegetationin Central Europe. In temperate forest ecosystems not affected by anthropogenic activities, nitrogenis a growth-limiting factor. Beech trees form mutualistic associations with ectomycorrhizal (EM)fungi, which have the ability to take up different inorganic and organic nitrogen-containingcompounds and to improve plant nitrogen-status. EM fungal communities and functions are thereforeof major interest for tree nutrition.In this work, the functional diversity of beech ectomycorrhizas with respect to nitrogen (N) andcarbon (C) availability has been investigated. The following hypotheses were tested:Mobilization of litter-derived nitrogen by EM fungi differs amongst fungal species in the firstphase of litter decomposition.Long-distance EM exploration types accumulate more litter-derived N than short distanceones, because of their higher accessibility to the litter.Differences in litter-derived N accumulation between EM fungal species decrease over timewith the increasing availability of litter-released N via the soil.Functional differences exist between EM fungal species with respect to nitrogen uptake andprocessing.

Agri-food enterprises are challenged by a multitude of complexities. The globalisation and increasing international competition in the food sector, the high degree of small- and medium-sized enterprises, as well as national and cross-national food crises and related uncertainties for consumers and agri-food enterprises lead to different public and private requirements. Transparency on products and inter-enterprise processes has become an important factor for competitiveness and trust in agri-food enterprises and their provided products. The provision of product- and process-related information for the timely discovery of critical situations in the distribution process requires the efficient organisation and coordination of inter-enterprise communication in order to react to these situations directly and effectively. Transparency, in respect to the shared understanding and undistorted access to product- and process-related information, represents an unresolved challenge for the organisation of inter-enterprise communication of relevant information.The objective of this thesis is to formulate a generic framework for the development of business information services, which connect distributed information sources at agri-food enterprises along the supply network, to provide relevant information to stakeholders to meet their information needs. Within this framework, generic service alternatives for static and dynamically changing information, service activation patterns matching the organisational needs of business interactions, as well as supportive technology components are described to establish this connection. The framework is applied to an application case concentrating on the fresh- fruit and vegetable supply network. Within this application case, three service alternatives are elaborated out of different identified information needs with the objective to provide decentralised stored product-quality and process-related information to users in order to identify deficient products or other critical issues in the distribution process. These services are developed in different levels of technology. An economic decision model is provided for the selection and adoption of technology related to these technology levels based on a generic cost-benefit-analysis and the consideration of the company¿s general ability to adopt new technology. The thesis closes with a discussion of different key requirements for the adoption of business information services in the food sector.

This study presents a method to assess yield performance of dual-purpose cowpea types for human consumption and to reveal potentials for further improvement of its use as leafy vegetable. Eleven cowpea accessions with different genetic background and sample status were chosen from AVRDC¿s working collection in Arusha, Tanzania. Among them, dual-purpose cowpeas like Dakawa, Ex Iseke and Ngoji were present that the center has been distributing to local farmers. Multi-location trials in typical cowpea production environments were established both on farm and on station in the regions Arusha, Dodoma, and Kilimanjaro in Tanzania and in Eastern Region, Uganda during the short and long rainy season 2007 and 2008, respectively. Young, tender leaves were picked in successive leaf harvests about every and two weeks until the plants did not produce further leaves. Cowpea seeds were harvested when pods reached 80% maturity. Data of yield parameters were analyzed with analysis of variance (ANOVA), stability analyses were carried out according to the dynamic and static concepts. Reliability of leaf and seed yield performances were calculated based on the probability of outperformance of local check cowpeas that were previously recommended by farmers and extension workers in informal group sessions.

While the trading prices of issued Certified Emission Reductions (CERs) within theEuropean Union Emissions Trading Scheme (EU-ETS) are transparent, there is limitedknowledge about the actual origination cost of Clean Development Mechanism (CDM)projects. Minimum CER prices required for financial viability of a CDM project ideadefine a measure for CDM cost effectiveness and indicate the floor price for projectparticipation. As CDM projects are located in developing countries, they face substantialimplementation and performance risks that need to be considered for CDM costeffectiveness calculation. As existing studies primarily focus on qualitative riskassessment, there is a lack of a monetary evaluation of risk impact on CDM originationcost and CER floor price.

Despite economic growths observed over the last half-century, global poverty and hunger still remain big challenges to overcome. Most of the poor people live in rural areas and depend on agriculture for livelihood. Advancements and access to agricultural innovations and skills are thus essential components for mass poverty alleviation. Apparently, a wide range of agricultural technologies are readily available for potential uptake; some of these technologies are specifically devised to address productivity improvements in crops that would otherwise be difficult to breed conventionally. However, the rate and scale of adoption of these technologies in developing countries is still less than expected. Technology adoption rates are even much lower in sub-Saharan Africa, a region that is persistently characterized by stagnated economic growth rates and deteriorating welfare conditions for its citizens.Literature on agricultural technology adoption and its actual or potential impacts in developing countries is vast. However, the general understanding of these effects is still hampered by the limited scope of robust economic studies. Particularly, most new technologies require farmers to substantially change traditional production practices in order to make significant gains, which often also requires access to new information and complementary input resources. The failure for existing studies to give considerable empirical detail to information and other related institutional constraints as well as the role of complementary inputs limits avenues for wider policy making. Moreover, it is reasonable that impact studies address broader welfare outcomes such as, the net effects of new technology on household income and food security. Although relatively more empirical evidence is available for income, quite little is known about the effect of new technology on improving household food security. The latter could be partly due to the conceptual complexities and costs involved in estimating household food security.

This thesis is concerned with the problem of optimally rearranging objects, in particular, railcars in a rail yard. The work is motivated by a research project of the Institute of Mathematical Optimization at Technische Universität Braunschweig, together with our project partner BASF, The Chemical Company, in Ludwigshafen. For many variants of such rearrangement problems ¿ including the real-world application at BASF ¿ we state the computational complexity by exploiting their equivalence to particular graph coloring, scheduling, and bin packing problems. We present mathematical optimization methods for determining schedules that are either optimal or close to optimal, and computational results are discussed from both a theoretical and practical point of view. In addition to the railway industry, there are other fields of application in which efficiently rearranging, sorting, or stacking is an important issue. For instance, the results obtained in this thesis could also be applied to solving certain piling problems in warehouses or container terminals.

The continuously expanding commercial air traffic of the last decades steadily increasedthe demand for highly efficient aircraft which offer extended operation timeswhile reducing costs and environmental impact at the same time. The associated designrequirements for reduced structural weight and improved fatigue life representthe major challenges for todays aircraft structures and have significantly intensifiedthe competition between metallic and composite airframe applications. New metallicdesign concepts try to face this competition by combining latest materials andinnovative manufacturing methods, like high speed machining, laser beam weldingor friction stir welding, which allows for possible savings with respect to structuralweight and manufacturing costs. However, due to their integral characteristics, thedamage tolerance behaviour of these new designs is generally inferior to the commondifferential design. Reliable estimations on the fatigue life of integrally stiffenedstructures consequently necessitate assessment methodologies that are capable to includeadditional manufacturing influences and offer numerical efficiency in order tobe practical for parametric studies during airframe design.Therefore, the development and enhancement of simulation methods for efficient andreliable evaluation of cracks and crack growth represents the main objective of thisthesis. Two simulation methods are implemented and investigated for this purpose,that are based on different approaches and intended for distinct applications. Onemethod is based on analytical stress function expressions and enables a very efficientevaluation of the complete fatigue crack growth life of cracked airframe structures.The proposed approach in this context is generally based on plane assumptions andlimited to pure mode I crack loading. In order to be able to additionally considercrack turning under mixed mode loading, a second simulation method is presentedwhich implements an extended finite element framework for a mesh independentrepresentation of cracks in two dimensions. The additional combination with thematerial force concept, as alternative crack state parameter, allows for automatedsimulations of crack growth under mixed mode loading without any need for remeshingoperations.Both simulation methods are validated based on different crack configurations andare applied for crack growth investigations of varying configurations of integrallystiffened panels under pure mode I and mixed mode loading conditions. In thiscontext, a special focus is set on the influences of additional internal stresses thatfollow either from the applied manufacturing processes or an intentional prestressingof the stiffeners. Despite the general limitation to plane considerations, the proposedmethods show a good accordance with experimental, theoretical and alternativenumerical results. This demonstrates their capabilities to simulate fatigue crackgrowth and crack turning in integrally stiffened airframe structures and motivatesfurther research with respect to a possible extension to three-dimensional problems.

Disparity and inequality have emerged as central issues in regional development realmwhich need to be worked out. In the case of Java Island ¿ Indonesia, even thoughinfrastructures mainly in transportati on and communicati on have already built-uprelati vely evenly compared to other islands in the country, it is in fact not suffi cientto reduce disparity and inequality among provinces or in each province within theisland. Furthermore, urbanizati on mostly in developing countries leads to the blurringof the disti ncti on between rural and urban areas. Concerning inequality that leads topropensity of unbalanced development patt erns as has been taking place in Java Islandincluding in Central Java Province as one big province in the Island, the emergingof rural-urban regions are considered to be further examined. Expectedly, furthercomprehension regarding the dynamics of these regions would be advantageous topromote balanced development as well as to enforce the creati on of integrated regionaldevelopment policies which are not simply dichotomized rural and urban regions.

A regression analysis describes the dependency of random variables in the form of a functional relationship. One distinguishes between the dependent response variable and one or more independent influence variables. There is a variety of model classes and inference methods available, ranging from the conventional linear regression model up to recent non- and semiparametric regression models. The so-called generalized regression models form amethodically consistent framework incorporating many regression approaches with response variables that are not necessarily normally distributed, including the conventional linear regression model based on the normal distribution assumption as a special case. Whenrepeated measurements are modeled in addition to fixed effects also random effects or coefficients can be included. Such models are known as Random Effects Models or Mixed Models. As a consequence, regression procedures are applicable extremely versatile andconsider very different problems.In this dissertation regularization techniques for generalized mixed models are developed that are able to perform variable selection. These techniques are especially appropriate when many potential influence variables are present and existing approaches tend to fail. First of all a componentwise boosting technique for generalized linear mixed models is presented which is based on the likelihood function and works by iteratively fitting the residuals using weak learners. The complexity of the resulting estimator is determined by information criteria. For the estimation of variance components two approaches are considered, an estimator resultingfrom maximizing the profile likelihood, and an estimator which can be calculated using an approximative EM-algorithm. Then the boosting concept is extended to mixed models with ordinal response variables. Two different types of ordered models are considered, the threshold model, also known as cumulative model, and the sequential model. Both are based on the assumption that the observed response variable results from a categorized version of a latent metric variable. In the further course of the thesis the boosting approach is extendedto additive predictors. The unknown functions to be estimated are expanded in B-spline basis functions, whose smoothness is controlled by penalty terms. Finally, a suitable L1-regularization technique for generalized linear models is presented, which is based on acombination of Fisher scoring and gradient optimization. Extensive simulation studies and numerous applications illustrate the competitiveness of the methods constructed in this thesis compared to conventional approaches. For the calculation of standard errors bootstrap methods are used.

Soluble N-ethylmaleimide-sensitive attachment receptor (SNARE) proteins are thekey players in membrane fusion. Localized in opposed membranes, they assemble viathe SNARE motif in a stable four-helix bundle bringing the membranes close to eachother and promoting membrane fusion by using the energy release during complexformation. SNARE complex assembly is regulated by several proteins. One of these,Complexin, is known to partially associate with the core complex, it may stabilizeSNARE complex intermediates and unbinds upon calcium trigger. Nevertheless, theexact function of Complexin is still under discussion. After membrane fusion therecycling of free SNARE proteins is mediated by the AAA+ protein NSF in conjunctionwith its cofactor a-SNAP. Afterwards, the individual SNARE proteins are available foranother round of membrane fusion.To date, no effective model systems for preventing or at least decelerating thedisassembly mechanism are known. Development of a potent inhibitor of the a-SNAP/NSF mediated disassembly was carried out. Therefore, the SNARE motif ofSynaptobrevin, one of the SNARE proteins, was used as a model system for theinvestigation of defined SNARE/SNAP complex recognition sites. The full length of theSNARE motif of Synaptobrevin was obtained using solid phase peptide synthesis.Different modifications at various residues within the sequence were introduced inorder to identify important interactions between a-SNAP and the SNARE complex andto prevent a-SNAP recognition.Additionally, the regulator protein Complexin was synthesized as a ß-peptide analog,also designed to inhibit the disassembly mechanism by preventing a-SNAPrecognition through enhanced interaction between the ß-mimic and theSynaptobrevin and Syntaxin helices. By development of the Complexin ß-peptidemimic as a 14-helix, the advantages of a well-defined secondary structure with highhelix propensity are obtained. Furthermore, the binding fragment of Complexin wasperformed as a-peptide, extended with amino acids known to promote the a-helicalpropensity.For understanding of biological systems the investigation of conformational dynamicsand interactions of individual proteins is important. Therefore, in a final part, smallindependently folding protein domains were synthesized by solid phase peptidesynthesis and labeled with respect to the development of the single moleculefluorescence spectroscopy (smFRET) technique. This method is a convenient tool ofmonitoring single folding and unfolding events of proteins.

In einer vergleichenden Studie zwischen Schüttelkolben und Bioreaktor wurden Morphologieund Laccaseausbeute eines mit dem Plasmid pYSK7 transformierten Stammes desBasidiomyceten Coprinopsis cinerea untersucht. Das verwendete Plasmid beinhaltet dasC. cinerea Laccase Gen lcc1, das in seiner Expression durch den Agaricus bisporus gpdIIPromotor kontrolliert wird. Der C. cinerea Transformant wuchs in beiden Kultivierungsformenin Form von Pellets, wobei die Pellets in den Schüttelkulturen bei 120 upm (Umdrehung proMinute) gleichmäßiger und kleiner waren als jene, die sich im Bioreaktor bei einerRührgeschwindigkeit von 120 upm ausbildeten. Im Rührkesselreaktor, in dem der pH Wertkonstant bei pH 6, pH 7 oder pH 8 gehalten wurde, konnte man eine höhere Fragmentierungder Pellets bei den höheren pH Werten pH 7 und pH 8 feststellen. Bei pH 6 zeigten diePellets allerdings eine gleichmäßigere Größe. Außerdem wurden die höchstenLaccaseaktivitäten in den Bioreaktorkulturen bei pH 6 gemessen. In den Schüttelkulturen, diebei 25 °C und 37 °C inkubiert wurden, konnten Laccaseaktivitäten von bis zu 10 U/ml bei derniedrigeren Kultivierungstemperatur von 25 °C erreicht werden.

For more than 20 years, the so-called field-oriented control is standard for controlled electric drive systems. Until now, the strategies based on this method fulfill completely the requirements of drive technology. However, due to the system characteristics, an arbitrary improvement of the controller properties is not possible. Predictive or precalculating control methods which need no controller cascade are an alternative.Main focus of this work is to examine model-based predictive controllers for their applicability in drive technology. These methods with their high prediction horizon are well-known from classic control theory and in process engineering they are applied with great success. Several strategies are presented, explained and evaluated, whereas, at the same time, the interested reader gets advice for the implementation of these methods. Since model-based predictive control is, until now, not very common in drive technology, this work also includes detailed derivations of the control algorithms.

In experimental economics cooperation is frequently modeledby a so-called public-good design. This design tries to depict theproblem that cooperation is benefi cial for every participant butthat there are individual incentives to free-ride, i.e., to invest nopersonal effort to increase the common welfare. In public-goodexperiments cooperation usually breaks down due to imperfectconditional cooperation if measures like sanction possibilities,reputation-building or communication are absent.We contribute to the literature in a number of ways. For examplewe introduce a new dynamic public-good design to analyzewhether subjects behave differently when they do not receivenew resources in a multiperiod public-good design. We furtherprovide a monitoring mechanism that mitigates the free-ridingproblem, in the fi rst study with a linear and in a second studywith a non-linear production function. However, the costlyimplementation of the monitoring in itself represents either a(second-level) step-level public-good or a second-level linearpublic-good in the latter case. Finally we introduce a limit onpunishment.

Die vorliegende Arbeit befasst sich mit der Struktur der Penumbra von Sonnen-¿ecken und dem Evershed Effekt (EE). Obwohl der EE seit über einhundert Jahrenbekannt ist, sind seine ursächlichen Mechanismen bisher nicht vollständig geklärt.Mittels hochaufgelöster spektropolarimetrischer Daten des SatellitenobservatoriumsHINODE werden sowohl das kleinskalige (¿ 240 km) penumbrale Magnetfeld, alsauch die Vertikal- und Horizontalkomponenten des EE untersucht.Am Anfang wird der Aufbau und die magnetische Aktivität der Sonne beschrie-ben. Eine Reihe von theoretischen Modellen zur Erklärung des EE werden disku-tiert und die theoretischen Grundlagen der Spektropolarimetrie werden zusam-mengefasst. Das Beobachtungsinstrument wird skizziert und eine Reihe von Meth-oden zur absoluten Wellenlängenkalibrierung sowie zur Untersuchung von solarenMaterieströmungen in der tiefen Photosphäre werden miteinander verglichen.Die Forschungsresultate zeigen, dass sich das penumbrale Geschwindigkeits-feld signi¿kant von dem der ruhigen Sonne unterscheidet. Morphologische Studienergeben elongierte Aufströmungen in der inneren und runde Abströmungen in deräußeren Penumbra, welche als Quellen und Senken des EE interpretiert werden.Für die Senken des EE konnte ein außerordentlich großer Zenitwinkel nachgewiesenwerden. Weiterhin ist anzumerken, dass die Plasmageschwindigkeit in den penum-bralen Abströmungen weit größer ist als in der ruhigen Sonne. Das kleinskaligeGeschwindigkeitsfeld innerhalb penumbraler Filamente wird statistisch und an-hand von Fallstudien untersucht, wobei die Vorhersagen von Flußröhrenmodellenbestätigt werden. Des Weiteren werden helle penumbrale Abströmungen beschrie-ben und zwei Klassen von penumbralen Filamenten identi¿ziert. Beobachtungenvon Flecken am Rand der Sonnenscheibe werden benutzt, um die Horizontalkom-ponente des EE zu untersuchen.

Stress during human pregnancy is associated with various adverse consequences for the physiological and psychological wellbeing of mother and child. A main focus for the research field of stress during pregnancy is to identify the underlying biological mechanism by which the maternal psychological stress is transferred to the developing foetus. Glucocorticoids, such as cortisol seem to play a pivotal role, since an overexposure of maternal cortisol, for example due to psychological stress is capable of crossing the placental barrier and thereby reaching the foetus. Heightened cortisol levels in the prenatal period have been associated with preterm birth and low birth weight. In animal studies, the placental enzyme 11¿-hydroxysteroid dehydrogenase type 2 (11¿-HSD2) which converts active cortisol into its inactive metabolite cortisone, protects the developing foetus against an overexposure to maternal cortisol concentrations. This enzyme is also present in the adult salivary glands, where it exerts the same conversion of cortisol to cortisone.The aim of the present thesis was to examine the psychological and physiological stress reactivity of pregnant women confronted with a standardized stressor and to concurrently investigate the conversion of cortisol to cortisone in the saliva and amniotic fluid of pregnant women.

The objective of this study was the investigation of the resistance of modifiedwood against sapstaining fungi and the investigation of the influences of fungalgrowth. Specimens of Scots pine sapwood (Pinus sylvestris L.) and Beech wood(Fagus sylvatica L.) were investigated after being treated with an amino-alkylfunctionaloligomeric siloxane, a sodium water glass solution and 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU).The following is a structured outline of this study:Laboratory tests for the resistance against the blue stain fungusAureobasidium pullulansThe objective was to develop a laboratory test method against blue stain formodified wood as well as the determination of the resistance against blue stain.After definition of a suitable test method, the laboratory tests displayed animproved resistance against blue stain for all tested modified wood specimens.Regardless of the wood species, the fungal infestation was reduced but notinhibited. Among the treated specimens, the water glass treated specimensshowed the lowest, the siloxane treated specimens the highest infestationrespectively.

Hundreds of millions of people all around the world have driven cars for over a century. Soon, technological progress will allow us to substitute the manually driven car with the autonomous vehicle. As the autonomous vehicle is considered to have the potential to disrupt the mobility industry, it is of high relevance for researchers and practitioners to examine this radical innovation from a consumer perspective. So far, we do not have a comprehensive understanding about the benefits that drive consumers¿ intention to use an autonomous vehicle in the future and the sacrifices that act as psychological barriers. Therefore, the goal of this thesis is to explore these benefits and sacrifices and investigate their importance for consumers¿ decision to use autonomous vehicles.For this thesis, a theoretical framework was developed by integrating the decomposed theory of reasoned action with an enhanced version of means-end theory. The framework led to the qualitative examination of benefits and sacrifices that consumers believe exist when using an autonomous vehicle. The relative importance of each benefit and sacrifice for the decision to use an autonomous vehicle in the future was then investigated with a quantitative study. In addition, four consumer segments that differ in their decision drivers and barriers were discovered with a latent class regression.The results of this thesis include several meaningful implications for practitioners and future research. These implications have the potential to guide managerial decision-making in the mobility and related industries and create an opportunity to directly influence the future of mobility by taking action to make the autonomous vehicle succeed in the market.