7,285 research outputs found
Does On-Farm quality Assurance Pay? A Cost-Benefit Analysis of the GrainSafe Program
Since the introduction of genetically modified (GM) crops, the commodity grain system has been under pressure to segregate GM and non-GM crops. Starting at the level of the grain handler, members of the grain supply chain have successfully used quality assurance and identity preservation programs to segregate non-GM crops. Producers delivering high value, identity preserved crops have become interested in implementing these quality management systems at the farm level. We conduct a cost-benefit analysis that shows that quality assurance program may be profitable for producers, depending on their farm size and equipment management strategy.on-farm quality assurance, identity preservation, cost-benefit analysis, @Risk
Genetic and Biochemical Characterization of COP1/SPA Funktion in Arabidopsis Photomorphogenesis
Plants as sessile organisms are dependent on a complex interaction with their
environment. Light is one of the most important factors that affect multiple stages of plant growth and development. In concert with the four SPA proteins (SPA1-SPA4) the E3-ubiquitin ligase COP1 acts as a repressor of light signaling in darkness. COP1 and SPA proteins were also found to regulate processes like Determination of leaf size, stomata differentiation and Induktion of photoperiodic flowering. In this regard, COP1 targets transcription factors like HY5, HFR1 or CO for ubiquitination and subsequent 26S proteasome-dependent degradation. Furthermore, SPA proteins physically interact with the COP1 protein.
In the present study I could show that SPA proteins can interact with each other in vitro and in planta, building homo- and heterodimers. This indicates the existence of larger COP1/SPA containing complexes in which every combination of SPA dimers is possible. Further, I could show that the N-terminus including the proteins’ coiled-coil domain mediates the interactions within the SPAs.
Since SPA proteins carry out overlapping but also distinct functions throughout plant development and this cannot be solely explained by their mRNA and Protein expression patterns, there must be other mechanisms regulating COP1/SPA complex assembly and/or activity. Using antibodies against native SPA1 and SPA2 protein generated in this study, I could show that SPA1 and SPA2 Protein levels decrease in far-red light compared to darkness, whereas transcript levels remained unchanged, pointing to a post-translational mechanism regulating SPA Funktion. However, whether this is dependent on COP1 needs to be verified. COP1/SPA complexes most likely are involved in a broad spectrum of developmental processes. Thus, I analyzed the regulation of two new potential targets, PAP1 and PAP2, which are transcription factors involved in the regulation of light-dependent anthocyanin biosynthesis. I could show that PAP1 and PAP2 interact with the members of COP1/SPA complexes in yeast. Further, I could show that PAP1 and PAP2 proteins from overexpressing plants are stabilized by light and accumulate upon treatment with the proteasomal blocker MG132, indicating a post-translational regulation of PAP protein abundance. Analysis of RNAi mutants and PAP overexpressing plants in cop1-4 background revealed an effect of the cop1 Mutation on PAP-dependent anthocyanin biosynthesis. Furthermore, an initial Experiment showed, that PAP2 protein in 35S::HA-PAP2 cop1-4 overexpressing plants is further stabilized in darkness and light compared to overexpressing lines in wild-type background, supporting the hypothesis that COP1/SPA complexes regulate PAP protein levels under both conditions
Tenfold your photons -- a physically-sound approach to filtering-based variance reduction of Monte-Carlo-simulated dose distributions
X-ray dose constantly gains interest in the interventional suite. With dose
being generally difficult to monitor reliably, fast computational methods are
desirable. A major drawback of the gold standard based on Monte Carlo (MC)
methods is its computational complexity. Besides common variance reduction
techniques, filter approaches are often applied to achieve conclusive results
within a fraction of time. Inspired by these methods, we propose a novel
approach. We down-sample the target volume based on the fraction of mass,
simulate the imaging situation, and then revert the down-sampling. To this end,
the dose is weighted by the mass energy absorption, up-sampled, and distributed
using a guided filter. Eventually, the weighting is inverted resulting in
accurate high resolution dose distributions. The approach has the potential to
considerably speed-up MC simulations since less photons and boundary checks are
necessary. First experiments substantiate these assumptions. We achieve a
median accuracy of 96.7 % to 97.4 % of the dose estimation with the proposed
method and a down-sampling factor of 8 and 4, respectively. While maintaining a
high accuracy, the proposed method provides for a tenfold speed-up. The overall
findings suggest the conclusion that the proposed method has the potential to
allow for further efficiency.Comment: 6 pages, 3 figures, Bildverarbeitung f\"ur die Medizin 202
Resonant enhancement of second harmonic generation in the mid-infrared using localized surface phonon polaritons in sub-diffractional nanostructures
We report on strong enhancement of mid-infrared second harmonic generation
(SHG) from SiC nanopillars due to the resonant excitation of localized surface
phonon-polaritons within the Reststrahlen band. The magnitude of the SHG peak
at the monopole mode experiences a strong dependence on the resonant frequency
beyond that described by the field localization degree and the dispersion of
linear and nonlinear-optical SiC properties. Comparing the results for the
identical nanostructures made of 4H and 6H SiC polytypes, we demonstrate the
interplay of localized surface phonon polaritons with zone-folded weak phonon
modes of the anisotropic crystal. Tuning the monopole mode in and out of the
region where the zone-folded phonon is excited in 6H-SiC, we observe a
prominent increase of the already monopole-enhanced SHG output when the two
modes are coupled. Envisioning this interplay as one of the showcase features
of mid-infrared nonlinear nanophononics, we discuss its prospects for the
effective engineering of nonlinear-optical materials with desired properties in
the infrared spectral range.Comment: 16 pages, 3 figure
Spherical nanoindentation – advancements and prospects towards its application as a multifunctional testing technique
With the development of modern high-performance materials and components, cases increase where conventional testing techniques used for the mechanical characterization miss their target. Material fabrication at a bench scale, miniaturization and not least cost-effectiveness yearn for a highly reliable, fast and highly automatable testing technique. Even though uniaxial micromechanical tests on micro-pillars or -tensile samples are well suitable for the extraction of flow curves, they face the problem of elaborate specimen manufacturing.
Spherical nanoindentation could be a candidate technique to overcome the mentioned drawbacks, since time needed for sample preparation is tremendously reduced. The present study will outline solutions of existing problems, which may lay the foundation for spherical nanoindentation to become a widely-used testing technique. Main objections concerning tip imperfections will be resolved by modifying the calibration procedure, and validated on a broad spectrum of materials independent of the indenter tip radius. Once the actual tip shape is available, displacement-time profiles can be designed to guarantee constant strain-rates during testing and thus permit the determination of the strain-rate sensitivity for rate-dependent materials. Finally, the comparison between nanoindentation flow curves and uniaxial tests will evidence that spherical indentation is a highly reliable technique for the extensive mechanical characterization of modern high-performance materials and show its high potential as a multifunctional standard testing technique.
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A Composite of Polyether Ether Ketone and Silica-Coated Copper Particles for Creating Tailored Conductive Tracks via Laser Printing
Conventional substrates for optoelectronic systems include inorganic or organic carrier materials; however, these systems are typically subjected to environmentally harmful multistep processes to prepare printed circuit boards. To mitigate these issues, the present article reports a polyether ether ketone (PEEK)-based composite densely filled with copper microparticles, prepared using a simple, cost-effective, and sustainable synthesis method. The material exhibits high thermal conductivity but is electrically nonconductive prior to undergoing laser treatment. To prevent the composite from exhibiting electrical conductivity, the copper particles are coated with a thin silica layer through a sol–gel reaction. The thermal stability of PEEK and the Cu–PEEK composites with Cu contents of up to 70 vol%, which are prepared via heat melding, is investigated by thermogravimetric analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy to clarify the manner in which copper affects the chemical structure of the polymer. The developed composite exhibits a significantly higher thermal conductivity than that of the unfilled PEEK polymer. This paper also describes the effects of laser treatment on the surface morphology. Overall, this study suggests that conductive tracks with low electrical resistance can be created on electrically insulating substrates with high thermal conductivity
Discovering the Child? Individualization Processes of Catholic Religious Education in the Horizon of Secularization since 1900
At the beginning of the 20th century, early processes of secularization – especially in working-class families living in large cities – and inadequate teaching methods led to a crisis of Catholic religious education. Teachers and professors highlighted that it was becoming more and more difficult for reliÂgious education to reach students and to ensure that they become devoted members of the Church. In this situation, a catechetical movement was established, which was mainly situated in Munich and Vienna, where teachers, catechists, and academics discussed reforms of the commonly used teaching methods in religious education. Conferences and the foundation of journals followed. It is at least from this point that the process of modernization in the field of religious education in the German-speaking context begins. This modernization gained traction after the Second Vatican Council and was also proÂmoted by the phenomenon of secularization and pluralization after the 1960s. Against this background, the essay will address the following questions: What led to the modernization of religious education that began around 1900? What role was played by the new openness of catechists and theologians for eduÂcation science and the (religious) pluralization of society? To answer this question, the article will focus on developments between 1900 and the 1920s, during the 1970s, and the more or less topical discusÂsion about the concept of ‘theology of children’ since the late 1990s. This study will also ask whether this development can be described as the discovery of the child in theology and religious education. Finally, this paper asks what consequences this development has for a denominational religious education in state schools today and in the future
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