University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Membrane. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

Structure of the rotor ring of F-Type Na+-ATPase from Ilyobacter tartaricus.

Abstract: In the crystal structure of the membrane-embedded rotor ring of the sodium ion-translocating adenosine 5'-triphosphate (ATP) synthase of Ilyobacter tartaricus at 2.4 angstrom resolution, 11 c subunits are assembled into an hourglass-shaped cylinder with 11-fold symmetry. Sodium ions are bound in a locked conformation close to the outer surface of the cylinder near the middle of the membrane. The structure supports an ion-translocation mechanism in the intact ATP synthase in which the binding site converts from the locked conformation into one that opens toward subunit a as the rotor ring moves through the subunit a/c interface.

Spectral Analysis of Signed Graphs for Clustering, Prediction and Visualization.

Abstract: We study the application of spectral clustering, prediction and visualization methods to graphs with negatively weighted edges. We show that several characteristic matrices of graphs can be extended to graphs with positively and negatively weighted edges, giving signed spectral clustering methods, signed graph kernels and network visualization methods that apply to signed graphs. In particular, we review a signed variant of the graph Laplacian. We derive our results by considering random walks, graph clustering, graph drawing and electrical networks, showing that they all result in the same formalism for handling negatively weighted edges. We illustrate our methods using examples from social networks with negative edges and bipartite rating graphs.

Gross growth efficiencies of protozoan and metazoan zooplankton and their dependence on food concentration, predator-prey weight ratio, and taxonomic group

Abstract: A comprehensive datasct on the gross growth efficiency (GGE) of planktonic protozoans and metazoans was gathered from the literature in order to (1) identify typical ranges of values, (2) to reexamine the taxon specificity of GGE, and (3) to evaluate the impact of food concentration, predator-prey weight ratio, and temperature on GGE. All taxa (i.e. nano/microAagellates, dinoflagellates, ciliates, rotifers, cladocerans, and copepods) were found to have mean and median GGE of -2O-30%. Contrary to the common practice of using different values of GGE for ciliates and crustaceans, I found that the GGE hardly differed between taxa. Variability within all taxa was high and could only partially be attributed to the independent variables mentioned above. The dependency of GGE on food concentrations was the most reliable relationship identified by multiple regression. Establishing further generalizations regarding the dependency of GGE on other factors was hampered by methodological differences among studies and taxa and the lack of information on other potentially important factors such as the clemental composition of prey items. Future studies of GGE should recognize the importance of these factors. Knowledge of fluxes of matter and energy within ecosystems is a prerequisite for the understanding of food web regulation and of the role that oceans and lakes play in the global carbon cycle (Longhurst 199 1). However, quantifying carbon fluxes reliably in particular ecosystems is hampered by many difficulties. The complexity of aquatic food webs outpaces our capacity to make all the necessary measure

Carbon nitride deposited using energetic species: a review on xps studies

Abstract: This paper reviews x-ray photoelectron spectroscopy studies on carbon nitride (CN) and reports on results obtained from CN thin films prepared by mass selected ion-beam deposition. The core-level spectra of samples deposited at room temperature show that nitrogen is incorporated into the amorphous network in two different bonding configurations; carbon has three main bonding configurations whose relative contributions vary as a function of the nitrogen content. For samples deposited at elevated temperatures an ordering of the amorphous CN network towards a crystalline graphitelike structure is observed. Furthermore, both deposition at elevated temperatures (350 \ifmmode^\circ\else\textdegree\fi{}C) and post-deposition ion irradiation have a strong influence on the bonding configuration in the CN films. Based on these results and the results reported in the reviewed literature a picture of the microstructure of carbon nitride deposited using energetic species is developed.

A review of volunteered geographic information quality assessment methods

Abstract: With the ubiquity of advanced web technologies and location-sensing hand held devices, citizens regardless of their knowledge or expertise, are able to produce spatial information. This phenomenon is known as volunteered geographic information VGI. During the past decade VGI has been used as a data source supporting a wide range of services, such as environmental monitoring, events reporting, human movement analysis, disaster management, etc. However, these volunteer-contributed data also come with varying quality. Reasons for this are: data is produced by heterogeneous contributors, using various technologies and tools, having different level of details and precision, serving heterogeneous purposes, and a lack of gatekeepers. Crowd-sourcing, social, and geographic approaches have been proposed and later followed to develop appropriate methods to assess the quality measures and indicators of VGI. In this article, we review various quality measures and indicators for selected types of VGI and existing quality assessment methods. As an outcome, the article presents a classification of VGI with current methods utilized to assess the quality of selected types of VGI. Through these findings, we introduce data mining as an additional approach for quality handling in VGI.