Tensile loaded membrane constructions without cutting patterns - computer based modeling and analysis of high points

In this paper, the high points of a stretch-tent construction are analyzed by using two different software programs. The modeling and results are verified by a puncture resistance testing. The possibilities and limits of the software programs are shown as well as the further research opportunities

Equity-Linked Pension Schemes with Guarantees

This paper analyses the relationship between the level of a return guarantee in an equity-linked pension scheme and the proportion of an investor's contribution needed to finance this guarantee. Three types of schemes are considered: investment guarantee, contribution guarantee and participation surplus. The evaluation of each scheme involves pricing an Asian option, for which relatively tight upper and lower bounds can be calculated in a numerically efficient manner. We find a negative (and for two contracts pecifications also concave) relationship between the participation in the surplus return of the investment strategy and the guarantee level in terms of a minimum rate of return. Furthermore, the introduction of a possibility of early termination of the contract (e.g. due to the death of the investor) has no qualitative and very little quantitative impact on this relationship.pension funds; forward risk adjusted measure; Asian option

Uniqueness of the Fair Premium for Equity-Linked Life Insurance Contracts

An equity-linked life insurance contract combines an endowment life insurance and an investment strategy with a minimum guarantee. The benefit of this contract is determined by the guaranteed amount plus a bonus equal to a call on the portfolio. This bonus is similar to an Asian option. We analyze the relationship between the periodic insurance premium and its proportional share invested into the portfolio. For a general model of the financial risks we show the existence and uniqueness of an insurance premium. Furthermore the premium is strictly increasing and convex as a function of the share invested. An earlier version of this paper was presented under the title Security Linked Life Policies under Stochastic Interest Rates .Asian option, forward risk adjusted measure, Monte Carlo simulations, life insurance, stochastic interest rates

Equity-linked life insurance - a model with stochastic interest rates

Assuming constant interest rates Brennan and Schwartz (1976, 1979) obtained the rational insurance premium on an equity-linked insurance contract through the application of the theory of contingent claims pricing. Further considerations with deterministic interest rates have been discussed in Aase and Persson (1992) and in Persson (1993). Analysing the single premium case Bacinello and Ortu (1993b) allow for the short term interest rate to develop in accordance to an Ornstein-Uhlenbeck process. In a paper from 1994 they consider extensions to both the single and the periodic premium model. This paper presents a model similar to the one by Bacinello and Ortu (1994) for the periodic premium case with a stochastic interest rate dynamic. It is shown that the insurance contract includes an Asian-like option contract. Sufficient conditions on the guaranteed amount for the existence of a solution are derived. As no closed form solution will be obtained, we discuss different numerical approaches and apply Monte Carlo simulations with a variance reduction technique.Asian option, forward risk adjusted measure, Monte Carlo simulations

Carrier relaxation dynamics in quantum dots: Scattering mechanisms and state-filling effects

Stressor-induced InxGa1−xAs quantum dot structures of high structural quality allow a detailed experimental investigation of carrier relaxation between distinct zero-dimensional quantized states. Time-resolved photoluminescence studies combined with appropriate model calculations show that state filling effects, Coulomb scattering, and acoustic phonon scattering determine the relaxation scenario in a way characteristic for a zero-dimensional electronic system. These investigations allow a quantitative estimation of the inter-dot-level relaxation rates mediated by (i) Coulomb scattering and (ii) acoustic phonon scattering.Peer reviewe

Engineering of tomato for the sustainable production of ketocarotenoids and its evaluation in aquaculture feed

Ketocarotenoids are high-value pigments used commercially across multiple industrial sectors as colorants and supplements. Chemical synthesis using petrochemical-derived precursors remains the production method of choice. Aquaculture is an example where ketocarotenoid supplementation of feed is necessary to achieve product viability. The biosynthesis of ketocarotenoids, such as canthaxanthin, phoenicoxanthin, or astaxanthin in plants is rare. In the present study, complex engineering of the carotenoid pathway has been performed to produce high-value ketocarotenoids in tomato fruit (3.0 mg/g dry weight). The strategy adopted involved pathway extension beyond β-carotene through the expression of the β-carotene hydroxylase (CrtZ) and oxyxgenase (CrtW) from Brevundimonas sp. in tomato fruit, followed by β-carotene enhancement through the introgression of a lycopene β-cyclase (β-Cyc) allele from a Solanum galapagense background. Detailed biochemical analysis, carried out using chromatographic, UV/VIS, and MS approaches, identified the predominant carotenoid as fatty acid (C14:0 and C16:0) esters of phoenicoxanthin, present in the S stereoisomer configuration. Under a field-like environment with low resource input, scalability was shown with the potential to deliver 23 kg of ketocarotenoid/hectare. To illustrate the potential of this “generally recognized as safe” material with minimal, low-energy bioprocessing, two independent aquaculture trials were performed. The plant-based feeds developed were more efficient than the synthetic feed to color trout flesh (up to twofold increase in the retention of the main ketocarotenoids in the fish fillets). This achievement has the potential to create a new paradigm in the renewable production of economically competitive feed additives for the aquaculture industry and beyond

Empirische Shortcuts:Studentische Forschungsprojekte in der Methodenlehre

Die empirische Bildungsforschung hat in den letzten Jahren einen nachhaltigen quantitativen und qualitativen Aufschwung genommen. Erziehungswissenschaftliche Forschung erschöpft sich jedoch nicht im M&E des schulischen Lernstands im nationalen und internationalen Vergleich und seiner Ursachen sondern umfasst ein weites Feld an Fragestellungen aus unterschiedlichsten Bereichen. Dies muss den Studierenden, neben den methodischen Modellen und Instrumentarien exemplarisch vermittelt werden. Das ideale didaktische Modell hierfür ist zweifellos ein von den Studierenden selbst konzipiertes und durchgeführtes Forschungsprojekt, wie es seit Jahren im Programmbereich „Empirische Pädagogik“ des Instituts für Erziehungswissenschaft der WWU Münster praktiziert. Dadurch werden den Studierenden Dimensionen eröffnet, die im Zeitalter von Modularisierung, OECD-Statistiken und Ressourcenverknappung sich zunehmend verengen. Die damit verbundenen Impulse und Erfahrungsgewinne sind in eine Belebung und Bereicherung des Studiums

Metabolic engineering of astaxanthin biosynthesis in maize endosperm and characterization of a prototype high oil hybrid

Maize was genetically engineered for the biosynthesis of the high value carotenoid astaxanthin in the kernel endosperm. Introduction of a β-carotene hydroxylase and a β-carotene ketolase into a white maize genetic background extended the carotenoid pathway to astaxanthin. Simultaneously, phytoene synthase, the controlling enzyme of carotenogenesis, was over-expressed for enhanced carotenoid production and lycopene ε-cyclase was knocked-down to direct more precursors into the β-branch of the extended ketocarotenoid pathway which ends with astaxanthin. This astaxanthin-accumulating transgenic line was crossed into a high oil- maize genotype in order to increase the storage capacity for lipophilic astaxanthin. The high oil astaxanthin hybrid was compared to its astaxanthin producing parent. We report an in depth metabolomic and proteomic analysis which revealed major up- or down- regulation of genes involved in primary metabolism. Specifically, amino acid biosynthesis and the citric acid cycle which compete with the synthesis or utilization of pyruvate and glyceraldehyde 3-phosphate, the precursors for carotenogenesis, were down-regulated. Nevertheless, principal component analysis demonstrated that this compositional change is within the range of the two wild type parents used to generate the high oil producing astaxanthin hybrid