Bias-Reduction in Variational Regularization

The aim of this paper is to introduce and study a two-step debiasing method for variational regularization. After solving the standard variational problem, the key idea is to add a consecutive debiasing step minimizing the data fidelity on an appropriate set, the so-called model manifold. The latter is defined by Bregman distances or infimal convolutions thereof, using the (uniquely defined) subgradient appearing in the optimality condition of the variational method. For particular settings, such as anisotropic $\ell^1$ and TV-type regularization, previously used debiasing techniques are shown to be special cases. The proposed approach is however easily applicable to a wider range of regularizations. The two-step debiasing is shown to be well-defined and to optimally reduce bias in a certain setting. In addition to visual and PSNR-based evaluations, different notions of bias and variance decompositions are investigated in numerical studies. The improvements offered by the proposed scheme are demonstrated and its performance is shown to be comparable to optimal results obtained with Bregman iterations.Comment: Accepted by JMI

Criteria for a transparent assessment of carbon footprints in the food supply chain

Our daily consumption patterns have a major influence on climate change. Several European initiatives use CO2-labels for products to provide guidance for climate friendly consumption decisions. Different methodological details affect the total amount of greenhouse gas emissions (CO2-e) being labeled. A standardized method is needed to generate comparable results. The objective of this study conducted at the Institute for Marketing and Innovation of the University of Natural Resources and Life Sciences, Vienna, was to identify the key methodological criteria for transparent assessment of the carbon footprint of food products. Expert interviews and content analyses were the methodological approach applied. Current carbon footprint standardization processes have to meet the challenge of meeting both scientific accuracy and practicability in order to enable comprehensive implementation in management practice

Mythos Résistance – Tabu Kollaboration

Die Darstellung der französischen 'Rolle' im Zweiten Weltkrieg erfuhr seit den 1980er Jahren bedeutende Veränderungen. Weg vom gaullistischen Mythos des widerständischen Frankreichs, entwickelte sich ein nuancierter und kritischer politischer Diskurs, der heute die Kollaboration und die Shoa thematisiert. Kristallisationspunkte markieren die Veränderung der französischen Gedächtnispolitik bis zur deutlichen Wende im Jahr 1995.The image of France's 'role' during the Second World War has considerably changed since the 1980s. Turning away from the 'gaullist myth' of France as the country of resistance, a multi-faceted and critical political discourse has been developed. Today's discourse broaches the issue of collaboration and Shoa. Focal points mark the change of the French politics of remembrance until its definit turn in 1995

Effect of ischemia on localization of heat shock protein 25 in kidney

Effect of ischemia on localization of heat shock protein 25 in kidney. The effects of renal ischemia on the intracellular distribution of the low-molecular weight heat shock protein (HSP)25 were examined using immunofluorescence microscopy. In all kidney zones, ischemia decreased HSP25 in the supernatant of the tissue homogenates and increased it in the pellet fraction (containing mainly nuclei and cytoskeletal components). This was associated with disappearance of HSP25 staining from the brush border of proximal convoluted tubule (PCT) cells. Because no nuclear staining of cortical tubule cells was apparent either in control or ischemic kidneys, ischemia seems to cause a closer association of HSP25 with cytoskeletal components. HSP25 probably participates in the postischemic restructuring of the cytoskeleton of PCT cells

On the origin of chirality in plasmonic meta-molecules

Chirality is a fundamental feature in all domains of nature, ranging from particle physics over electromagnetism to chemistry and biology. Chiral objects lack a mirror plane and inversion symmetry and therefore cannot be spatially aligned with their mirrored counterpart, their enantiomer. Both natural molecules and artificial chiral nanostructures can be characterized by their light-matter interaction, which is reflected in circular dichroism (CD). Using DNA origami, we assemble model meta-molecules from multiple plasmonic nanoparticles, representing meta-atoms accurately positioned in space. This allows us to reconstruct piece by piece the impact of varying macromolecular geometries on their surrounding optical near fields. Next to the emergence of CD signatures in the instance that we architect a third dimension, we design and implement sign flipping signals through addition or removal of single particles in the artificial molecules. Our data and theoretical modelling reveal the hitherto unrecognized phenomenon of chiral plasmonic-dielectric coupling, explaining the intricate electromagnetic interactions within hybrid DNA-based plasmonic nanostructures.Comment: Article and Supporting Informatio