700 research outputs found

    Cost Decision Support in Product Design

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    The constraints addressed in decision making during product design, process planning and production planning determine the admissible solution space for the manufacture of products. The solution space determines largely the costs that are incurred in the production process. In order to be able to make economically sound decisions, costing data support must be integrated into the decision making processes. Regarding product design, the designer must be supplied with transparent costing data, that is ready for direct application. In this paper a functional architecture for costing data support during product design, as well as a corresponding data structure are presented

    Analysis of the three lowest bending frequencies of a rotating propeller

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    The available literature on rotating propeller oscillations reveals a lack of uniformity in interpretation, particularly as concerns the data on the overtone frequency with respect to the centrifugal forces. The present report is a survey of the existing data for computing the bending frequency and a check on the dependability of the calculating methods

    The 1926 German seaplane contest

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    The report discusses the problem of rating the various seaplane designs from the 1926 seaplane contest. The whole process of rating consists in measuring the climbing speed, flying weight and carrying capacity of a seaplane and then using these data as the basis of a construction problem

    Effectiveness of Light-Quality and Dark-White Growth Light Shifts in Short-Term Light Acclimation of Photosynthesis in Arabidopsis

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    Photosynthesis needs to run efficiently under permanently changing illumination. To achieve this, highly dynamic acclimation processes optimize photosynthetic performance under a variety of rapidly changing light conditions. Such acclimation responses are acting by a complex interplay of reversible molecular changes in the photosynthetic antenna or photosystem assemblies which dissipate excess energy and balance uneven excitation between the two photosystems. This includes a number of non-photochemical quenching processes including state transitions and photosystem II remodeling. In the laboratory such processes are typically studied by selective illumination set-ups. Two set-ups known to be effective in a highly similar manner are (i) light quality shifts (inducing a preferential excitation of one photosystem over the other) or (ii) dark-light shifts (inducing a general off-on switch of the light harvesting machinery). Both set-ups result in similar effects on the plastoquinone redox state, but their equivalence in induction of photosynthetic acclimation responses remained still open. Here, we present a comparative study in which dark-light and light-quality shifts were applied to samples of the same growth batches of plants. Both illumination set-ups caused comparable effects on the phosphorylation of LHCII complexes and, hence, on the performance of state transitions, but generated different effects on the degree of state transitions and the formation of PSII super-complexes. The two light set-ups, thus, are not fully equivalent in their physiological effectiveness potentially leading to different conclusions in mechanistic models of photosynthetic acclimation. Studies on the regulation of photosynthetic light acclimation, therefore, requires to regard the respective illumination test set-up as a critical parameter that needs to be considered in the discussion of mechanistic and regulatory aspects in this subject. Copyright © 2022 Hommel, Liebers, Offermann and Pfannschmidt

    Spatio-temporal expression of nuclear-encoded proteins associated to the plastid-encoded RNA polymerase essential for chloroplast biogenesis in Arabidopsis thaliana L.

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    The development of functional chloroplasts originating from undifferentiated proplastids is a complex process that depends on the proper function of the plastid-encoded RNA polymerase (PEP). The PEP complex comprises the plastid-encoded bacteria-like core-proteins αββ ʹβʺ and 12 tightly associated, nuclear-encoded proteins (PAPs; Steiner et al., 2011; Pfalz and Pfannschmidt, 2013). Biochemical analyses suggest expression and assembly of these proteins appears in a development- and/or light-dependent manner, however, this process is far from understood. It, however, represents a bottleneck in chloroplast biogenesis since genetic inactivation of any PAP disturbs the plastid gene expression resulting in an ivory/albino mutant phenotype. This thesis provides a detailed catalogue of the temporal and spatial expression of PAP genes during seedling development and describes novel and unexpected features of PAP localization, particularly with regard to the dual distribution between nucleus and plastid. Future studies will target mechanisms that control this dual localization and will aim to identify a transcriptional master regulator of the PAPs. The reporter lines that were designed during this thesis will provide useful tools for the assessment of these open questions

    Cross-cultural adaptation of the delphi definitions of low back pain prevalence (German DOLBaPP)

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    Background Assessed dimensions of low back pain (LBP) vary in prevalence studies. This may explain the heterogeneity in frequency estimates. To standardize definitions of LBP, an English consensus with 28 experts from 12 countries developed the “Delphi Definitions of Low Back Pain Prevalence” (DOLBaPP). The optimal definition and the shorter minimal definition with the related questionnaires for online, paper, and face-to-face use and telephone surveys are suitable for population-based studies. The definitions have to be adapted to different languages and cultures to provide comparable frequency estimates. The objective was to culturally adapt and pre-test the English definitions and corresponding Delphi DOLBaPP questionnaire forms into German. Methods The German DOLBaPP adaptation was conducted using the systematic approach suggested by Beaton et al. A pre-test of the Delphi DOLBaPP optimal paper questionnaire including an additional evaluation form was conducted in a sample of 121 employees (mainly office workers). In order to evaluate the comprehensibility, usability, applicability, and completeness of the adapted questionnaire, response to the questionnaire and 6 closed evaluation questions were analyzed descriptively. Qualitative methods were used for the 3 open questions of the evaluation form. Results The cultural adaptation of the DOLBaPP for a German-speaking audience required little linguistic adaptation. Conceptual equivalence was difficult for the expression “low back pain”. The expert committee considered the face validity of the pre-final version of the related Delphi DOLBaPP questionnaires as good. In the pre-test, most participants (95%) needed less than 5 minutes to fill in the optimal Delphi DOLBaPP questionnaire. They were generally positive regarding length, wording, diagram, and composition. All subjects with LBP (n = 61 out of 121 – 50.4%) answered the questions on functional limitation, sciatic pain, frequency and duration of symptoms as well as pain severity. Conclusion The results indicate that the cross-cultural German adaptation of the DOLBaPP Definitions and the corresponding questionnaires was successful. The definitions can be used in epidemiological studies to measure the prevalence of LBP. Some critical issues were raised regarding the general features of the Delphi DOLBaPP questionnaires. Future research is needed to evaluate these instruments
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