Understanding resilience of farming systems: Insights from system dynamics modelling for an arable farming system in the Netherlands

Farming systems in Europe are facing economic, social, environmental and institutional challenges. Highly intensive, climate-exposed, arable farming systems like the Veenkoloniën in the north of the Netherlands are particularly vulnerable to many of these challenges. Just in the past twenty years, the Veenkoloniën has lost half of its small and medium sized family farms specialised in cultivating starch potatoes. While starch potato production continues to be stable as the remaining farms are increasing the size of their operation, local stakeholders are concerned that the farming system in the Veenkoloniën is endangered. In this paper we investigate this issue by using a system dynamics simulation model to explore what the potential structures are that could threaten the long term future of starch potato production and to identify leverage points that can enhance the resilience of the system. Our analysis shows that, so far, farmers’ active engagement in a processing cooperative has been an important element to their resilience to cope with economic and environmental challenges. In practice, the cooperative has been able to act as a buffer and stabilise prices for farmers in the region by implementing strategies that increase the value of their products, open new markets and increase starch potato production.publishedVersio

Modellability of System Characteristics - Using Formal Mark-up Languages for Change Capability by Design

AbstractChange capability enables a production system to cope with external influences in an efficient, fast and self-organized manner. Several approaches have been designed for measuring change capability by specific indicators which represent core characteristics of production systems. On the other hand, formal modelling languages are used for production system design. Unfortunately, these languages do not match with system characteristics and especially with those indicators of change capability. Due to this missing linkage, existent production system models don’t facilitate the implementation of a system's change capability by design. Goal of this contribution is to point out the possibilities of operationalization approaches and their potential to be extended for (formal) modelling of system characteristics and sub properties, exemplified by using the concept of change capability. Additionally, the potential of change capability to be representable in a formal language will be exemplarily outlined by emphasizing on Systems Modelling Language (SysML). For this purpose, a qualitative approach with an emphasis on literature- and content analysis will be applied. Results of this contribution are (1) to pinpoint the research gap (which is also of crucial practical relevance) and (2) to point out possible solution approaches for a formal modellability of system characteristics

Cholesterol Slows down the Lateral Mobility of an Oxidized Phospholipid in a Supported Lipid Bilayer

We investigated the mobility and phase-partitioning of the fluorescent oxidized phospholipid analogue 1-palmitoyl-2-glutaroyl-sn-glycero-3-phospho-N-Alexa647-ethanolamine (PGPE-Alexa647) in supported lipid bilayers. Compared to the conventional phospholipid dihexadecanoylphosphoethanolamine (DHPE)-Bodipy we found consistently higher diffusion constants. The effect become dramatic when immobile obstacles were inserted into the bilayer. which essentially blocked the diffusion of DHPE-Bodipy but hardly influenced the movements of PGPE-Alexa647. In a supported lipid bilayer made of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), the differences in probe mobility leveled off with increasing cholesterol content. Using coarse-grained molecular dynamics simulations, we could ascribe this effect to increased interactions between the oxidized phospholipid and the membrane matrix, concomitant with a translation in the headgroup position of the oxidized phospholipid: at zero cholesterol content, its headgroup is shifted to the outside of the DOPC headgroup region, whereas increasing cholesterol concentrations pulls the headgroup into the bilayer plane

Extensive de novo solid-state NMR assignments of the 33kDa C-terminal domain of the Ure2 prion

We present the de novo resonance assignments for the crystalline 33kDa C-terminal domain of the Ure2 prion using an optimized set of five 3D solid-state NMR spectra. We obtained, using a single uniformly 13C, 15N labeled protein sample, sequential chemical-shift information for 74% of the N, Cα, Cβ triples, and for 80% of further side-chain resonances for these spin systems. We describe the procedures and protocols devised, and discuss possibilities and limitations of the assignment of this largest protein assigned today by solid-state NMR, and for which no solution-state NMR shifts were available. A comparison of the NMR chemical shifts with crystallographic data reveals that regions with high crystallographic B-factors are particularly difficult to assign. While the secondary structure elements derived from the chemical shift data correspond mainly to those present in the X-ray crystal structure, we detect an additional helical element and structural variability in the protein crystal, most probably originating from the different molecules in the asymmetric unit, with the observation of doubled resonances in several parts, including entire stretches, of the protein. Our results provide the point of departure towards an atomic-resolution structural analysis of the C-terminal Ure2p domain in the context of the full-length prion fibril

Peer mentoring for first-year students: Evaluation mentee academic performance in dependence of different mentoring styles.

Universities often offer support programs to assist first-year students with the transition from school to university. The purpose of this study was to examine the effects of different mentoring styles on mentee academic performance after one year and two years of study. Participants consisted of 828 psychology students who started their course of study in winter term 2006/07 or 2007/08 at the University of Vienna. 328 students from winter term 2007/08 participated in the peer mentoring program Cascaded Blended Mentoring (Leidenfrost …), in which they were supported by 48 student mentors (advanced students) in small groups. The mentoring groups were classified according to one of three mentoring styles described by Leidenfrost, Strassnig, Schabmann, Carbon, and Spiel (2011): motivating master mentoring, informatory standard mentoring, and negative minimalist mentoring. Our data suggest that participants in the mentoring program performed better in their studies. Mentees from winter term 2007/08 achieved better average grades than non-mentees from winter term 2007/08. They passed a higher number of courses than non-mentees from winter term 2007/08 and students from winter term 2006/07. There was, however, no specific impact of the different mentoring styles on mentee academic performance

Yersinia enterocolitica exploits different pathways to accomplish adhesion and toxin injection into host cells.

The current paradigm suggests that Yersinia enterocolitica (Ye) adheres to host cells via the outer membrane proteins Yersinia adhesin A (YadA) or invasin (Inv) to facilitate injection of Yops by the type III secretion system. In this process Inv binds directly to β1 integrins of host cells while YadA may bind indirectly via extracellular matrix proteins to β1 integrins. Here we challenged this paradigm and investigated the requirements for Yop injection. We demonstrate that Inv- but not YadA-mediated adhesion depends on β1 integrin binding and activation, and that tight adhesion is a prerequisite for Yop injection. By means of novel transgenic cell lines, shRNA approaches and RGD peptides, we found that YadA, in contrast to Inv, may use a broad host cell receptor repertoire for host cell adhesion. In the absence of β1 integrins, YadA mediates Yop injection by interaction with αV integrins in cooperation with yet unknown cofactors expressed by epithelial cells, but not fibroblasts. Electron microscopic and flow chamber studies revealed that a defined intimate contact area between Ye and host cells resulting in adhesion forces resisting shear stress is required for Yop injection. Thus, the indirect binding of YadA to a broad extracellular matrix (ECM) binding host cell receptor repertoire of different cell types makes YadA a versatile tool to ensure Yop injection. In conclusion, given the differential expression of the outer membrane proteins Inv and YadA in the course of Ye infection and differential expression of integrins by various host cell populations, the data demonstrate that Ye is flexibly armed to accomplish Yop injection in different host cell types, a central event in its immune evasion strategy

Improved Sterilization of Sensitive Biomaterials with Supercritical Carbon Dioxide at Low Temperature: Research Article

The development of bio-resorbable implant materials is rapidly going on. Sterilization of those materials is inevitable to assure the hygienic requirements for critical medical devices according to the medical device directive (MDD, 93/42/EG). Biopolymer-containing biomaterials are often highly sensitive towards classical sterilization procedures like steam, ethylene oxide treatment or gamma irradiation. Supercritical CO2 (scCO2) treatment is a promising strategy for the terminal sterilization of sensitive biomaterials at low temperature. In combination with low amounts of additives scCO2 treatment effectively inactivates microorganisms including bacterial spores. We established a scCO2 sterilization procedure under addition of 0.25% water, 0.15% hydrogen peroxide and 0.5% acetic anhydride. The procedure was successfully tested for the inactivation of a wide panel of microorganisms including endospores of different bacterial species, vegetative cells of gram positive and negative bacteria including mycobacteria, fungi including yeast, and bacteriophages. For robust testing of the sterilization effect with regard to later application of implant materials sterilization all microorganisms were embedded in alginate/agarose cylinders that were used as Process Challenge Devices (PCD). These PCD served as surrogate models for bioresorbable 3D scaffolds. Furthermore, the impact of scCO2 sterilization on mechanical properties of polysaccharide-based hydrogels and collagen-based scaffolds was analyzed. The procedure was shown to be less compromising on mechanical and rheological properties compared to established low-temperature sterilization methods like gamma irradiation and ethylene oxide exposure as well as conventional steam sterilization. Cytocompatibility of alginate gels and scaffolds from mineralized collagen was compared after sterilization with ethylene oxide, gamma irradiation, steam sterilization and scCO2 treatment. Human mesenchymal stem cell viability and proliferation were not compromised by scCO2 treatment of these materials and scaffolds. We conclude that scCO2 sterilization under addition of water, hydrogen peroxide and acetic anhydride is a very effective, gentle, non-cytotoxic and thus a promising alternative sterilization method especially for biomaterials

Profillinie 5: Kommunikation, Medien, Technik:

Die Forschungsprofillinie 5 “Kommunikation, Medien, Technik” entstand im Jahr 2005 aus der ursprünglichen Profillinie “Medien, Kommunikation und Informationstechnologien”. Sie zeigt heute eine deutlich stärkere Vernetzung über die verschiedenen Fakultäten hinweg, als das die bisherige Ausrichtung des Profils leisten konnte. Der wesentliche Unterschied zu den anderen Forschungsprofillinien der Technischen Universität Chemnitz besteht darin, dass hier der Mensch als der Nutzer technischer Systeme im Zentrum steht. Dies bedeutet jedoch nicht, dass vor allem sozial-, verhaltens- und kulturwissenschaftlich orientierte Professuren die Forschungsprofillinie tragen. Ganz im Gegenteil ist gerade in diesem Themenbereich eine enge Kooperation von naturwissenschaftlichen und technischen Disziplinen auf der einen Seite und sozialwissenschaftlichen Fächern auf der anderen Seite gefordert

Solid-state NMR sequential assignments of the amyloid core of Sup35pNM

Sup35pNM represents the N-terminal and middle (M) domains of the yeast Saccharomyces cerevisiae prion Sup35p. This fragment is commonly used for structural and functional studies of Sup35p. We here present a solid-state NMR study of fibrils formed by this fragment and show that sequential assignments can be obtained for the rigid and well-ordered parts of the protein using 3D spectroscopy. We describe in detail the sequential assignment of the 22 residues yielding strong, narrow signals with chemical shifts that correspond mostly to β-sheet secondary-structured amino acids that form the fibril core

Solid-state NMR sequential assignments of the amyloid core of full-length Sup35p

Sup35p is a yeast prion and is responsible for the [PSI +] trait in Saccharomyces cerevisiae. With 685 amino acids, full-length soluble and fibrillar Sup35p are challenging targets for structural biology as they cannot be investigated by X-ray crystallography or NMR in solution. We present solid-state NMR studies of fibrils formed by the full-length Sup35 protein. We detect an ordered and rigid core of the protein that gives rise to narrow and strong peaks, while large parts of the protein show either static disorder or dynamics on time scales which interfere with dipolar polarization transfer or shorten the coherence lifetime. Thus, only a small subset of resonances is observed in 3D spectra. Here we describe in detail the sequential assignments of the 22 residues for which resonances are observed in 3D spectra: their chemical shifts mostly corresponding to β-sheet secondary structure. We suspect that these residues form the amyloid core of the fibril