Well-posedness of a class of hyperbolic partial differential equations on the semi-axis

In this article we study a class of hyperbolic partial differential equations of order one on the semi-axis. The so-called port-Hamiltonian systems cover for instance the wave equation and the transport equation, but also networks of the aforementioned equations fit into this framework. Our main results firstly characterize the boundary conditions which turn the corresponding linear operator into the generator of a strongly continuous semigroup. Secondly, we equip the equation with inputs (control) and outputs (observation) at the boundary and prove that this leads to a well-posed boundary control system. We illustrate our results via an example of coupled transport equations on a network, that allows to model transport from and to infinity. Moreover, we study a vibrating string of infinite length with one endpoint. Here, we show that our results allow to treat cases where the physical constants of the string tend to zero at infinity.Comment: 26 page

Representing glaciers in a regional climate model

A glacier parameterization scheme has been developed and implemented into the regional climate model REMO. The new scheme interactively simulates the mass balance as well as changes of the areal extent of glaciers on a subgrid scale. The temporal evolution and the general magnitude of the simulated glacier mass balance in the European Alps are in good accordance with observations for the period 1958-1980, but the strong mass loss towards the end of the twentieth century is systematically underestimated. The simulated decrease of glacier area in the Alps between 1958 and 2003 ranges from −17.1 to −23.6%. The results indicate that observed glacier mass balances can be approximately reproduced within a regional climate model based on simplified concepts of glacier-climate interaction. However, realistic results can only be achieved by explicitly accounting for the subgrid variability of atmospheric parameters within a climate model grid bo

Evaluation of river flood extent simulated with multiple global hydrological models and climate forcings

Global flood models (GFMs) are increasingly being used to estimate global-scale societal and economic risks of river flooding. Recent validation studies have highlighted substantial differences in performance between GFMs and between validation sites. However, it has not been systematically quantified to what extent the choice of the underlying climate forcing and global hydrological model (GHM) influence flood model performance. Here, we investigate this sensitivity by comparing simulated flood extent to satellite imagery of past flood events, for an ensemble of three climate reanalyses and 11 GHMs. We study eight historical flood events spread over four continents and various climate zones. For most regions, the simulated inundation extent is relatively insensitive to the choice of GHM. For some events, however, individual GHMs lead to much lower agreement with observations than the others, mostly resulting from an overestimation of inundated areas. Two of the climate forcings show very similar results, while with the third, differences between GHMs become more pronounced. We further show that when flood protection standards are accounted for, many models underestimate flood extent, pointing to deficiencies in their flood frequency distribution. Our study guides future applications of these models, and highlights regions and models where targeted improvements might yield the largest performance gains

Stories that Change Our World? Narratives of the Sustainable Economy

Narratives are shaping our understanding of the world. They convey values and norms and point to desirable future developments. In this way, they justify and legitimize political actions and social practices. Once a narrative has emerged and this world view is supported by broad societal groups, narratives can provide powerful momentum to trigger innovation and changes in the course of action. Narratives, however, are not necessarily based on evidence and precise categories, but can instead be vague and ambiguous in order to be acceptable and attractive to different actors. However, the more open and inclusive a narrative is, the less impact can be expected. We investigate whether there is a shared narrative in research for the sustainable economy and how this can be evaluated in terms of its potential societal impact. The paper carves out the visions for the future that have been underlying the research projects conducted within the German Federal Ministry of Education and Research (BMBF) funding programme “The Sustainable Economy”. It then analyzes whether these visions are compatible with narratives dominating societal discourse on the sustainable economy, and concludes how the use of visions and narratives in research can contribute to fostering societal transformations

Using our agrobiodiversity: plant-based solutions to feed the world

International audienceAbstractThe growing global demand for food poses a serious challenge to mankind: How can we provide an increasing world population with an adequate, reliable and nutritious food supply? We argue that this can best be achieved through the utilization of biodiversity and the inclusion of marginal arable lands for agricultural production, while maintaining a broad gene pool to secure the potential for future plant production and supporting rural agricultural communities. We present several specific examples of how an emphasis on agricultural biodiversity can provide the basis for a nutritional, reliable, culinary and sustainable food production, and analyse the advantages, limitations and risks of an increased focus on agrobiodiversity. We conclude that the potential for approaches based on the preservation and development of existing agrobiodiversity has not been given sufficient attention in the current scientific and political debates concerning the best strategy to keep pace with global population growth and increasing demand for food. An emphasis on agrobiodiversity is the basis for the most appropriate strategies if the goal is to feed the world in the twenty-first century

Metastasierungsverhalten des kolorektalen Karzinoms

Background. Molecular differences in colorectal cancer (CRC) are associated with the metastatic route. Patient survival is mainly driven by metastatic spread thus it is imperative to understand its key drivers to develop biomarkers for risk stratification, follow-up protocols and personalized therapy. Thus, this study aimed to identify genes associated with the metastatic route in CRC. Material and Methods. CRC patients resected at our clinic from 2005 to 2014 and with a minimum 5-year follow-up were included in this analysis and grouped into CRC with hepatic (HEP), peritoneal (PER) or without distant metastases (M0), and HEP/PER. Firstly, tumor RNA of 6 patients each was isolated by microdissection from formalin-fixed paraffin-embedded specimens and analyzed by a NanoString analysis. Subsequently, these results were validated with immunohistochemistry and correlated to clinicopathological parameters in a larger collective of CRC patients (HEP n=51, PER n=44, M0 n=47, HEP/PER n=28). Results. Compared to M0, HEP tumors showed 20 differentially expressed genes associated with epithelial-mesenchymal transition (EMT) and angiogenesis. Compared to M0, PER tumors had 18 differentially expressed genes. The finding of different gene signatures was supported by the multidimensional principal component clustering analysis. Tumor perforation did not influence the metastatic route. CIB1 was homogenously and significantly overexpressed in HEP compared to M0 (p<0.001), but not in PER. Furthermore, immunohistochemical validation demonstrated that the mean CIB1 expression in HEP was 80% higher than in M0 (p<0.001). Conclusion. Gene expression analysis revealed that CIB1 is significantly overexpressed in CRC leading to liver metastases compared to M0 and PER. Thus, the present results suggest that CIB1 may play a crucial role for hematogenous spread to the liver but not for peritoneal carcinomatosis. Consequently, CIB1 seems to be a promising prognostic marker and a potential tool for future targeted therapies as well as early diagnostics and follow-up

Site demand adaption and production potential for birch in Gävleborg County

Large amounts of birch-timber are imported to Sweden, from particularly the Baltic States, since the domestic production can’t support the pulp industry. The goal of this study was to show the potential of birch and the area’s most suitable for birch production. The study was limited to Gävleborg County. Using site characteristics, site index (SI) for birch was estimated on all National Forest Inventory plots in Gävleborg County. Based on these estimations the site characteristics that gave the highest production for birch was found. To find the highest producing (m3sk ha-1 yr-1) birch sites in Gävleborg County and their size, a GIS-model divided in three classes was created. The birch production was also compared with the production-showing tree species (pine or spruce) on the plot to find the areas where birch best could match their production. The sites where birch had the highest production were low altitude and mesic sites with rich field layer type and slopes, in the southern parts of Gävleborg County. When birch was compared with pine and spruce, the sites where birch best could match their production were: low altitude and mesic sites with poor field layer type and slopes. Compared with pine, birch produced better in the southern parts of Gävleborg County, but that was not the case when comparing birch with spruce. The GIS-analysis showed that 15,4 % of all forested land qualified in class 1, the best class. In class 2, 57,4 % of the forested land was placed, and 27,2 % in class 3 with the lowest production.Vårt mål med den här studien var att visa att det finns alternativ till trädslagen gran och tall i det svenska skogsbruket. Det finns redan idag ett behov av björk till industrin och därför kändes det passande att skriva om vilka ståndorter som bäst lämpar sig för björkproduktion. Även ämnet ståndortsanpassning är väldigt aktuellt i nuläget och förhoppningsvis kan vårt arbete ge vägledning om vilka marker som björk lämpar sig bäst på. Detta arbete är gjort inom kursen kandidatarbete i skogsvetenskap på jägmästarprogrammet, SLU. Vi vill rikta ett tack till Ulf Johansson, försöksledare på Tönnersjöhedens och Skarhults försöksparker, för hjälp med att förstå regressionsmodellen, Mats Högström, Institutionen för skoglig resurshushållning, för all hjälp med GIS-analysen samt vänner och familj för givande diskussioner och korrekturläsning

Strong polarization mode coupling in microresonators

We observe strong modal coupling between the TE00 and TM00 modes in Si3N4 ring resonators revealed by avoided crossings of the corresponding resonances. Such couplings result in significant shifts of the resonance frequencies over a wide range around the crossing points. This leads to an effective dispersion that is one order of magnitude larger than the intrinsic dispersion and creates broad windows of anomalous dispersion. We also observe the changes to frequency comb spectra generated in Si3N4 microresonators due polarization mode and higher-order mode crossings and suggest approaches to avoid these effects. Alternatively, such polarization mode-crossings can be used as a novel tool for dispersion engineering in microresonators.Comment: Comments are very welcome (send to corresponding author

Age-related macular degeneration associated polymorphism rs10490924 in ARMS2 results in deficiency of a complement activator

Background Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. The polymorphism rs10490924 in the ARMS2 gene is highly associated with AMD and linked to an indel mutation (del443ins54), the latter inducing mRNA instability. At present, the function of the ARMS2 protein, the exact cellular sources in the retina and the biological consequences of the rs10490924 polymorphism are unclear. Methods Recombinant ARMS2 was expressed in Pichia pastoris, and protein functions were studied regarding cell surface binding and complement activation in human serum using fluoresence-activated cell sorting (FACS) as well as laser scanning microscopy (LSM). Biolayer interferometry defined protein interactions. Furthermore, endogenous ARMS2 gene expression was studied in human blood derived monocytes and in human induced pluripotent stem cell- derived microglia (iPSdM) by PCR and LSM. The ARMS2 protein was localized in human genotyped retinal sections and in purified monocytes derived from AMD patients without the ARMS2 risk variant by LSM. ARMS2 expression in monocytes under oxidative stress was determined by Western blot analysis. Results Here, we demonstrate for the first time that ARMS2 functions as surface complement regulator. Recombinant ARMS2 binds to human apoptotic and necrotic cells and initiates complement activation by recruiting the complement activator properdin. ARMS2-properdin complexes augment C3b surface opsonization for phagocytosis. We also demonstrate for the first time expression of ARMS2 in human monocytes especially under oxidative stress and in microglia cells of the human retina. The ARMS2 protein is absent in monocytes and also in microglia cells, derived from patients homozygous for the ARMS2 AMD risk variant (rs10490924). Conclusions ARMS2 is likely involved in complement- mediated clearance of cellular debris. As AMD patients present with accumulated proteins and lipids on Bruch’s membrane, ARMS2 protein deficiency due to the genetic risk variant might be involved in drusen formation