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Institution

University of Bremen

EducationBremen, Germany
About: University of Bremen is a education organization based out in Bremen, Germany. It is known for research contribution in the topics: Population & Glacial period. The organization has 14563 authors who have published 37279 publications receiving 970381 citations. The organization is also known as: Universität Bremen.


Papers
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Journal ArticleDOI
29 Dec 2010-PLOS ONE
TL;DR: This study shows that statistically significant co-occurrence of chronic diseases can be subsumed in three prevalent multimorbidity patterns if accounting for the fact that different multimor bidity patterns share some diagnosis groups, influence each other and overlap in a large part of the population.
Abstract: Objective Multimorbidity is a common problem in the elderly that is significantly associated with higher mortality, increased disability and functional decline. Information about interactions of chronic diseases can help to facilitate diagnosis, amend prevention and enhance the patients' quality of life. The aim of this study was to increase the knowledge of specific processes of multimorbidity in an unselected elderly population by identifying patterns of statistically significantly associated comorbidity.

317 citations

Journal ArticleDOI
TL;DR: The ecological niches of methanotrophic Archaea seem to be mainly defined by the availability of methane and sulfate, but it remains open which additional factors lead to the dominance of ANME-I or -II in the environment.
Abstract: The anaerobic oxidation of methane (AOM) is one of the major sinks for methane on earth and is known to be mediated by at least two phylogenetically different groups of anaerobic methanotrophic Archaea (ANME-I and ANME-II) We present the first comparative in vitro study of the environmental regulation and physiology of these two methane-oxidizing communities, which occur naturally enriched in the anoxic Black Sea (ANME-I) and at Hydrate Ridge (ANME-II) Both types of methanotrophic communities are associated with sulfate-reducing-bacteria (SRB) and oxidize methane anaerobically in a 1:1 ratio to sulfate reduction (SR) They responded sensitively to elevated methane partial pressures with increased substrate turnover The ANME-II-dominated community showed significantly higher cell-specific AOM rates Besides sulfate, no other electron acceptor was used for AOM The processes of AOM and SR could not be uncoupled by feeding the SRB with electron donors such as acetate, formate or molecular hydrogen AOM was completely inhibited by the addition of bromoethanesulfonate in both communities, indicating the participation of methanogenic enzymes in the process Temperature influenced the intensity of AOM, with ANME-II being more adapted to cold temperatures than ANME-I The variation of other environmental parameters, such as sulfate concentration, pH and salinity, did not influence the activity of both communities In conclusion, the ecological niches of methanotrophic Archaea seem to be mainly defined by the availability of methane and sulfate, but it remains open which additional factors lead to the dominance of ANME-I or -II in the environment

315 citations

Journal ArticleDOI
TL;DR: In this paper, porewater profiles of sulfate with constant gradients above the transition zones are indicative for anaerobic methane oxidation controlling sulfate reduction, and flux calculations were carried out on the basis of the determined pore water profiles revealed that anaerobacterial methane oxidation accounts for 100% of deep sulfur reduction within the sulfate-methane transition zone and consumes the total net diffusive sulfate flux.

314 citations

Journal ArticleDOI
TL;DR: A review of existing attempts to define and classify SoS is used to identify several dimensions that characterise SoS applications and the state of the art for SoS modelling, architectural description, simulation, verification, and testing is reviewed.
Abstract: The term “System of Systems” (SoS) has been used since the 1950s to describe systems that are composed of independent constituent systems, which act jointly towards a common goal through the synergism between them. Examples of SoS arise in areas such as power grid technology, transport, production, and military enterprises. SoS engineering is challenged by the independence, heterogeneity, evolution, and emergence properties found in SoS. This article focuses on the role of model-based techniques within the SoS engineering field. A review of existing attempts to define and classify SoS is used to identify several dimensions that characterise SoS applications. The SoS field is exemplified by a series of representative systems selected from the literature on SoS applications. Within the area of model-based techniques the survey specifically reviews the state of the art for SoS modelling, architectural description, simulation, verification, and testing. Finally, the identified dimensions of SoS characteristics are used to identify research challenges and future research areas of model-based SoS engineering.

314 citations

Journal ArticleDOI
01 Apr 2008
TL;DR: The h(t) solution, as it includes the gravity term (hydrostatic pressure), enables the calculation of the liquid rise behavior for longer times than the classical Lucas-Washburn equation.
Abstract: We derive an analytic solution for the capillary rise of liquids in a cylindrical tube or a porous medium in terms of height h as a function of time t. The implicit t(h) solution by Washburn is the basis for these calculations and the Lambert W function is used for its mathematical rearrangement. The original equation is derived out of the 1D momentum conservation equation and features viscous and gravity terms. Thus our h(t) solution, as it includes the gravity term (hydrostatic pressure), enables the calculation of the liquid rise behavior for longer times than the classical Lucas-Washburn equation. Based on the new equation several parameters like the steady state time and the validity of the Lucas-Washburn equation are examined. The results are also discussed in dimensionless form.

314 citations


Authors

Showing all 14961 results

NameH-indexPapersCitations
Roger Y. Tsien163441138267
Klaus-Robert Müller12976479391
Ron Kikinis12668463398
Ulrich S. Schubert122222985604
Andreas Richter11076948262
Michael Böhm10875566103
Juan Bisquert10745046267
John P. Sumpter10126646184
Jos Lelieveld10057037657
Michael Schulz10075950719
Peter Singer9470237128
Charles R. Tyler9232531724
John P. Burrows9081536169
Hans-Peter Kriegel8944473932
Harald Haas8575034927
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023343
2022709
20212,106
20202,309
20192,191
20181,965