760 research outputs found
Mapping and regionalisation of permafrost phenomena as a basis for natural hazard analyses in South Tyrol (Italy)
No full textIn the Rieserferner-Ahrn Nature Park (South Tyrolean Alps, Italy) a detailed mapping of the spatial distribution ofpermafrost phenomena is carried out in order to provide the basis for natural hazards analyses. The study is based on the surveying of the characteristics of geomorphological, hydrological and physical permafrost indicators, such as rock glaciers, ice-cored debris and moraine deposits, perennial snow patches, temperatures at the base of the winter snow cover (BTS) as well as temperatures and electrical conductivity of melt water. By means of a statistical model an analysis is made as to what extent the spatial density of perennial snow patches is appropriate to forecast the spatial distribution of permafrost. First results show that this approach - that was not considered useful so far - provides a significant approximation for determining the lower limit of discontinuous permafrost areas
Manfred Moritz 60 Jahre alt
No full textAm 12. September 1991 beging der Arachnologe Dr. Manfred MORITZ (Berlin) seinen 60. Geburtstag. Sein langjähriges Wirken als Kustos am Museum für Naturkunde der Humboldt-Universität zu Berlin, das seinen Niederschlag auch in zahlreichen wissenschaftlichen Publikationen und umfangreicher
Korrespondenz fand, wird aus der Sicht des Gratulanten dargestellt
A Fun-Loving Friend in Solidarity and Comrade: An Obituary for Bodo Zeuner (1942-2021)
No full textBodo Zeuner war der PROKLA als Autor und Mitglied des Fördervereins 50 Jahre eng verbunden, arbeitete in den 1970er-Jahren im Redaktionskollektiv Gewerkschaften mit. Am 30. November verstarb Bodo Zeuner im Alter von 79 Jahren.Bodo Zeuner was closely associated with PROKLA for 50 years as an author and member of the friends’ association, and worked in the editorial collective trade unions in the 1970s. On November 30, Bodo Zeuner died at the age of 79
Argininmethyliertes hnRNP K - Synthese und kombinatorische Multidomänen-Nukleinsäure-Assoziation
No full textDie biophysikalische Analyse der Argininmethylierung bedarf ausreichender Mengen des modifizierten Proteins. Die Methylierung von heterogenem nukleären Ribonukleoprotein K (hnRNP K) wurde durch Koexpression von protein arginine methyltransferase 1 in E. coli erreicht und ist mit der Methylierung des Säugerproteins identisch. Rekombinantes nicht-methylierte und methyliertes Protein wurde für vergleichende Untersuchungen der Aggregation, Proteininteraktion und RNA-Bindung genutzt. Die beobachtete Aggregation von hnRNP K ist vom Methylierungsstatus unabhängig, reversibel und kann durch hohe Ionenstärken oder Osmolyte verhindert werden. Gleichgewichts-Assoziationen mit repetetiven pyrimidin-reichen DNAs und RNAs wurden mittels Fluoreszenztitrationen untersucht. Die Stöchiometrie eines sequenziellen Bindemechanismus und die einzelnen Dissoziationskonstanten wurden bestimmt. Die Sequenzabhängigkeit der Assoziation deutet darauf hin, dass alle hnRNP K homology (KH)- Domänen von hnRNP K an der Wechselwirkung partizipieren, wobei die erste und zweite KH-Domäne als Tandem-Domäne und die dritte KH-Domäne unabhängig fungieren.Analysis of arginine methylation requires access to methylated protein for biophysical and biochemical analyses. Methylation of heterogeneous nuclear ribonucleoprotein K (hnRNP K) upon co-expression with protein arginine methyltransferase 1 in E. coli was found to be identical to the modification of hnRNP K from mammalian cells. Recombinant non-methylated and arginine-methylated hnRNP K was used to characterize self-aggregation, protein-protein interaction and nucleic acid binding. Reversible self-aggregation is independent of hnRNP Ks methylation but can be prevented by high ionic strength and specific osmolytes. Steady state association of hnRNP K with pyrimidine repeat-containing RNA and DNA was analyzed by fluorescence titration. The stoichiometry of a sequencial binding mechanism and the individual affinity constants were determined. Sequence dependence of association, measured by steady state competition assay, indicate that all hnRNP K homology (KH) domains of hnRNP K contribute differentially to RNA binding, with KH1-KH2 acting as a tandem domain and KH3 as an individual binding domain.von Bodo Morit
Learning in networks: An experimental study using stationary concepts
No full textOur study analyzes theories of learning for strategic interactions in networks. Participants played two of the 2 x 2 games used by Selten and Chmura (2008) and in the comment by Brunner, Camerer and Goeree (2009). Every participant played against four neighbors and could choose a different strategy against each of them. The games were played in two network structures: a lattice and a circle. We compare our results with the predictions of different theories (Nash equilibrium, quantal response equilibrium, action-sampling equilibrium, payoff-sampling equilibrium, and impulse balance equilibrium) and the experimental results of Selten and Chmura (2008). One result is that the majority of players choose the same strategy against each neighbor. As another result we observe an order of predictive success for the stationary concepts that is different from the order shown by Selten and Chmura. This result supports our view that learning in networks is different from learning in random matching. --experimental economics,networks,learning
Biophysical and biochemical analysis of hnRNP K: arginine methylation, reversible aggregation and combinatorial binding to nucleic acids
No full textAnalysis of arginine methylation, which affects specific protein interactions in eukaryotic cells, requires access to methylated protein for biophysical and biochemical studies. Methylation of heterogeneous nuclear ribonucleoprotein K (hnRNP K) upon co-expression with protein arginine methyltransferase 1 in E. coli was monitored by mass spectrometry and found to be identical to the modification of hnRNP K purified from mammalian cells. Recombinant non-methylated and arginine-methylated hnRNP K ((Met)hnRNP K) were used to characterize self-aggregation and nucleic acid binding. Analytical ultracentrifugation and static light scattering experiments revealed that hnRNP K methylation does not impact reversible self-aggregation, which can be prevented by high ionic strength and organic additives. Filter binding assays were used to compare the binding of non-methylated and (Met)hnRNP K to the pyrimidine repeat-containing differentiation control element (DICE) of reticulocyte 15-lipoxygenase mRNA 3' UTR. No affinity differences were detected for both hnRNP K variants. A series of oligonucleotides carrying various numbers of C-4 motifs at different positions was used in steady state competition assays with fluorescently-labeled functional differentiation control element (2R). Quantitative evaluation indicated that all hnRNP K homology domains of hnRNP K contribute differentially to RNA binding, with KH1-KH2 acting as a tandem domain and KH3 as an individual binding domain
A simple questionnaire can change everything: Are strategy choices in coordination games stable?
No full textThis paper presents results from an experiment designed to study the effect of self reporting risk preferences on strategy choices made in a subsequently played 2x2 coordination game. The main finding is that the act of answering a questionnaire about one's own risk preferences significantly alters strategic behavior. Within a best response correspondence framework, this result can be explained by a change in either risk preferences or beliefs. We find that self reporting risk preferences induces an increase in subjects' risk aversion while keeping their beliefs unchanged. Our findings raise some questions about the stability of strategy choices in coordination games. --coordination game,questionnaire,risk preferences,beliefs,best response correspondence
Untersuchungen zur Bedeutung von CAVEOLIN-1, VE-CADHERIN und CONNEXIN-43 an der Helium-vermittelten Regulation der endothelialen Permeabilität
No full textBackground: Recent studies suggested that helium is able to protect the heart against ischemia/reperfusion injury. We have recently shown that helium attenuates permeability of monolayers of HUVEC and that helium leads to decreased intra-cellular protein levels of caveolin-1 (Cav-1). Nevertheless, the underlying cellular and molecular mechanisms and the precise role of Cav-1 in helium-mediated regulation of endothelial barrier integrity are still unclear. We therefore investigated whether Cav-1 is involved in helium-mediated stabilization of the endothelial barrier and whether the expression of the key junctional molecules vascular endothelial-cadherin (VE-cadherin) and connexin-43 (Cx43) is regulated by helium and might be involved in the effects of helium on the endothelial barrier function. Methods: HUVEC were either exposed to 20 min of helium or control gas. Permeability was measured using confluent monolayers of HUVEC on microporous membranes and FITC-BSA flow through. To investigate if the effects of helium on the endothelial barrier function are related to Cav-1, HUVEC were transfected with Cav-1 siRNA prior to helium application. Expression of VE-cadherin and Cx43 was analyzed by western blotting. Results: While helium attenuated permeability of HUVEC monolayers in non-transfected HUVEC, effects of helium on cell permeability were abrogated in Cav-1 siRNA transfected HUVEC, suggesting a key role of Cav-1 in endothelial permeability. In the helium group, protein analyses in cell lysates showed a significantly higher expression of VE-cadherin and Cx43 at 6 and 12 hours. Transfecting HUVEC with Cav-1 siRNA abolished the effect of helium on VE-cadherin and Cx43 expression, pointing towards a role of Cav-1 in the helium-induced alteration of junctional molecule expression. Conclusion: Our findings suggest that Cav-1 is involved in the helium-mediated attenuation of HUVEC permeability and in the helium-mediated increase in the expression of VE-cadherin and Cx43.Hintergrund: Wir zeigten kürzlich, dass Helium die Permeabilität von HUVEC-Monolayers und die intrazellulären Proteinspiegel von Caveolin-1 (Cav-1) verringert. Dennoch sind die zugrundeliegenden zellulären und molekularen Mechanismen und die genaue Rolle von Cav-1 bei der Helium-vermittelten Regulation der Endothelbarriere noch unklar. Wir untersuchten daher, ob Cav-1 an der Helium-vermittelten Stabilisierung der endothelialen Barrierefunktion beteiligt ist und ob die Expression von VE-Cadherin und Connexin-43 (Cx43) durch Helium reguliert wird und möglicherweise an der Wirkung von Helium auf die endotheliale Barrierefunktion beteiligt ist. Methoden: HUVEC wurden entweder mit 20 min Helium oder Kontrollgas behandelt. Die Permeabilität wurde mittels konfluenter HUVEC-Monolayers auf mikroporösen Membranen und FITC-BSA Durchflusses gemessen. Um zu untersuchen, ob die Auswirkungen von Helium auf die endotheliale Barrierefunktion von Cav-1 abhängig sind, wurden HUVEC vor der Heliumapplikation mit Cav-1-siRNA transfiziert. Die Expression von VE-Cadherin und Cx43 wurde durch Western Blot gemessen. Ergebnisse: Während Helium die Permeabilität von HUVEC-Monolayers in nicht transfizierten HUVEC verminderte, wurde die Wirkung von Helium auf die Permeabilität in Cav-1-siRNA-transfizierten HUVEC aufgehoben, was auf eine Schlüsselrolle von Cav-1 für die Endothelpermeabilität hindeutet. In der Heliumgruppe zeigten Proteinanalysen von Zelllysaten eine signifikant höhere Expression von VE-Cadherin und Cx43 nach 6 und 12 Stunden. Die Transfektion von HUVEC mit Cav-1-siRNA hob die Wirkung von Helium auf die Expression von VE-Cadherin und Cx43 auf und wies auf eine Rolle von Cav-1 bei der Helium-induzierten Regulation der Expression von VE-Cadherin und Cx43 hin. Schlussfolgerung: Unsere Ergebnisse legen nahe, dass Cav-1 an der Helium-vermittelten Verminderung der endothelialen Permeabilität und erhöhten Expression von VE-Cadherin und Cx43 beteiligt ist
Experimental evidence of context-dependent preferences in risk-free settings
No full textThis study investigates context effects in general and the compromise effect in particular. It is argued that earlier research in this area lacks realism, a shortcoming that is a major drawback to research conclusions and stated management implications. The importance of this issue is stressed by previous research showing that behavioral anomalies found in hypothetical experimental settings tend to be significantly reduced when real payoff mechanisms are introduced. Therefore, to validate the compromise effect, an enhanced design is presented with participants making binding purchase decisions in the laboratory. We find that the compromise effect holds for real purchase decisions, and therefore is validated, and is not an artificial effect in surveys on hypothetical buying decisions. While conclusions and implications for marketing managers, derived in previous work assume that context effects hold for real market decisions, the results created by this enhanced design close this gap in the literature. --decision-making,anomalies,irrelevant alternatives,context effects
Upstalsboom - An Example of Caring Economics
No full textIn recent years, innovative approaches to corporate culture and leadership, such as the concept of New Work and its meaning and value-oriented corporate management, are gaining attention in science and organizational practice. However, critical voices doubt their feasibility citing challenges associated with their benefit realization. Nevertheless, through a case study of Upstalsboom, a German medium-sized family business in the tourism industry, the authors of this article illustrate how a people-centered, meaning-oriented corporate culture, and values-based leadership are not only possible and successful, but also sustainable from a crisis-resistant stability and resilience perspective. A reconstruction of the company\u27s development along biographical events and lived experiences of the CEO and co-author, Bodo Janssen, shows a high congruence with Riane Eisler’s path leading to the development of her concept of Caring Economics and caring organizational policies through a partnership orientation - the antithesis of dominance orientation systems
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