scispace - formally typeset
Search or ask a question
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
More filters
Journal ArticleDOI
TL;DR: A review of the advances in stratospheric aerosol research can be found in this article, with a focus on the agreement between in situ and space-based inferences of aerosol properties during volcanically quiescent periods.
Abstract: Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes.

299 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a discourse approach to the study of legitimacy of governance beyond the democratic state, starting from the empirical question of how international organizations legitimate themselves beyond the traditional democratic state.
Abstract: This article presents a discourse approach to the study of legitimacy of governance beyond the democratic state. It starts from the empirical question of how international organizations legitimate ...

299 citations

21 May 2014
TL;DR: Given a fixed state description based on instantiated predicates, a general abstraction scheme is provided to automatically create admissible domain-independent memory-based heuristics for planning problems, where abstractions are found in factorizing the planning space.
Abstract: Heuristic search planning effectively finds solutions for large planning problems, but since the estimates are either not admissible or too weak, optimal solutions are found in rare cases only In contrast, heuristic pattern databases are known to significantly improve lower bound estimates for optimally solving challenging single-agent problems like the 24-Puzzle or Rubik’s Cube This paper studies the effect of pattern databases in the context of deterministic planning Given a fixed state description based on instantiated predicates, we provide a general abstraction scheme to automatically create admissible domain-independent memory-based heuristics for planning problems, where abstractions are found in factorizing the planning space We evaluate the impact of pattern database heuristics in A* and hill climbing algorithms for a collection of benchmark domains

299 citations

Journal ArticleDOI
04 Apr 2003-Science
TL;DR: It is concluded that Afro-Asian monsoonal rains did not cross the subtropical desert zone during the early to mid-Holocene and is best explained by enhancement and southward extension of rainfall from Mediterranean sources.
Abstract: Paleosalinity and terrigenous sediment input changes reconstructed on two sediment cores from the northernmost Red Sea were used to infer hydrological changes at the southern margin of the Mediterranean climate zone during the Holocene. Between approximately 9.25 and 7.25 thousand years ago, about 3 per thousand reduced surface water salinities and enhanced fluvial sediment input suggest substantially higher rainfall and freshwater runoff, which thereafter decreased to modern values. The northern Red Sea humid interval is best explained by enhancement and southward extension of rainfall from Mediterranean sources, possibly involving strengthened early-Holocene Arctic Oscillation patterns and a regional monsoon-type circulation induced by increased land-sea temperature contrasts. We conclude that Afro-Asian monsoonal rains did not cross the subtropical desert zone during the early to mid-Holocene.

298 citations

Journal ArticleDOI
TL;DR: In this article, the effect of cooling and lubrication during the grinding process of a machined part has been investigated in the field of fluid dynamic processes in supply nozzles and in the grinding zone, thus offering the chance to minimize the amount of coolant in circulation.

298 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
Network Information
Related Institutions (5)
ETH Zurich
122.4K papers, 5.1M citations

93% related

University of Hamburg
89.2K papers, 2.8M citations

92% related

Centre national de la recherche scientifique
382.4K papers, 13.6M citations

92% related

Technische Universität München
123.4K papers, 4M citations

91% related

École Polytechnique Fédérale de Lausanne
98.2K papers, 4.3M citations

91% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023343
2022709
20212,106
20202,309
20192,191
20181,965