Institution
University of Bremen
Education•Bremen, Germany•
About: University of Bremen is a education organization based out in Bremen, Germany. It is known for research contribution in the topics: Population & Context (language use). The organization has 14563 authors who have published 37279 publications receiving 970381 citations. The organization is also known as: Universität Bremen.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: Repairs inhibition may well explain the potentiation of genotoxic effects by arsenic in combination with other DNA damaging agents and may thus be of high relevance for the carcinogenic action of arsenic compounds.
Abstract: Even though epidemiological studies have identified arsenic compounds as carcinogenic to humans, they are not mutagenic in bacterial and mammalian test systems. However, they increase the mutagenicity and clastogenicity in combination with other DNA damaging agents and there are indications of inhibition of DNA repair processes. We investigated the effect of arsenic(III) on nucleotide excision repair (NER) after UV irradiation in human fibroblasts in detail by using two repair-proficient and one partly repair-deficient xeroderma pigmentosum group C human fibroblast cell lines. The results show that two steps of NER are affected by arsenite. Most severely, the incision frequency is reduced at concentrations as low as 2.5 microM arsenic(III); at higher, cytotoxic concentrations, the ligation of repair patches is also impaired. Furthermore, our results indicate that both the global genome repair pathway and the transcription-coupled repair pathway are affected by arsenite. Repair inhibition may well explain the potentiation of genotoxic effects by arsenic in combination with other DNA damaging agents and may thus be of high relevance for the carcinogenic action of arsenic compounds.
184 citations
••
TL;DR: A review of conventional 2D as well as 3D roughness parameters, with particular emphasis on recent international standards and developments, and a discussion on the relevance of the different parameters and quantification methods in terms of functional correlations.
183 citations
••
Met Office1, National Center for Atmospheric Research2, University of Barcelona3, Barcelona Supercomputing Center4, University of Bremen5, Alfred Wegener Institute for Polar and Marine Research6, Max Planck Society7, Centre national de la recherche scientifique8, University of California, Irvine9, Niigata University10, Gwangju Institute of Science and Technology11, University of Alaska Fairbanks12
TL;DR: The Polar Amplification Model Intercomparison Project (PAMIP) contribution to the sixth iteration of CMIP6 as mentioned in this paper seeks to improve our understanding of this phenomenon through a coordinated set of numerical model experiments documented here.
Abstract: . Polar amplification – the phenomenon where external radiative
forcing produces a larger change in surface temperature at high latitudes
than the global average – is a key aspect of anthropogenic climate change,
but its causes and consequences are not fully understood. The Polar
Amplification Model Intercomparison Project (PAMIP) contribution to the sixth
Coupled Model Intercomparison Project (CMIP6; Eyring et al., 2016) seeks to
improve our understanding of this phenomenon through a coordinated set of
numerical model experiments documented here. In particular, PAMIP will
address the following primary questions: (1) what are the relative roles of
local sea ice and remote sea surface temperature changes in driving polar
amplification? (2) How does the global climate system respond to changes in
Arctic and Antarctic sea ice? These issues will be addressed with multi-model
simulations that are forced with different combinations of sea ice and/or sea
surface temperatures representing present-day, pre-industrial and future
conditions. The use of three time periods allows the signals of interest to
be diagnosed in multiple ways. Lower-priority tier experiments are proposed
to investigate additional aspects and provide further understanding of the
physical processes. These experiments will address the following specific
questions: what role does ocean–atmosphere coupling play in the response to
sea ice? How and why does the atmospheric response to Arctic sea ice depend
on the pattern of sea ice forcing? How and why does the atmospheric response
to Arctic sea ice depend on the model background state? What have been the
roles of local sea ice and remote sea surface temperature in polar
amplification, and the response to sea ice, over the recent period since
1979? How does the response to sea ice evolve on decadal and longer
timescales? A key goal of PAMIP is to determine the real-world situation using imperfect
climate models. Although the experiments proposed here form a coordinated
set, we anticipate a large spread across models. However, this spread will
be exploited by seeking “emergent constraints” in which model uncertainty
may be reduced by using an observable quantity that physically explains the
intermodel spread. In summary, PAMIP will improve our understanding of the
physical processes that drive polar amplification and its global climate
impacts, thereby reducing the uncertainties in future projections and
predictions of climate change and variability.
183 citations
••
TL;DR: In this paper, the authors describe the development of a new, community best-practice NO2 retrieval algorithm based on a synthesis of existing approaches, and implement an enhanced spectral fitting method for NO2, a 1°''×''1° TM5-MP data assimilation scheme to estimate the stratospheric background and improve air mass factor calculations.
Abstract: . Global observations of tropospheric nitrogen dioxide (NO2) columns have been shown to be feasible from space, but consistent multi-sensor records do not yet exist, nor are they covered by planned activities at the international level. Harmonised, multi-decadal records of NO2 columns and their associated uncertainties can provide crucial information on how the emissions and concentrations of nitrogen oxides evolve over time. Here we describe the development of a new, community best-practice NO2 retrieval algorithm based on a synthesis of existing approaches. Detailed comparisons of these approaches led us to implement an enhanced spectral fitting method for NO2, a 1° × 1° TM5-MP data assimilation scheme to estimate the stratospheric background and improve air mass factor calculations. Guided by the needs expressed by data users, producers, and WMO GCOS guidelines, we incorporated detailed per-pixel uncertainty information in the data product, along with easily traceable information on the relevant quality aspects of the retrieval. We applied the improved QA4ECV NO2 algorithm to the most current level-1 data sets to produce a complete 22-year data record that includes GOME (1995–2003), SCIAMACHY (2002–2012), GOME-2(A) (2007 onwards) and OMI (2004 onwards). The QA4ECV NO2 spectral fitting recommendations and TM5-MP stratospheric column and air mass factor approach are currently also applied to S5P-TROPOMI. The uncertainties in the QA4ECV tropospheric NO2 columns amount to typically 40 % over polluted scenes. The first validation results of the QA4ECV OMI NO2 columns and their uncertainties over Tai'an, China, in June 2006 suggest a small bias (−2 %) and better precision than suggested by uncertainty propagation. We conclude that our improved QA4ECV NO2 long-term data record is providing valuable information to quantitatively constrain emissions, deposition, and trends in nitrogen oxides on a global scale.
183 citations
••
TL;DR: In this article, the impact of uncertainty, distance, and conflict on key elements comprising the quality of the relationship between U.S. industrial exporters and their overseas customers was examined.
183 citations
Authors
Showing all 14961 results
Name | H-index | Papers | Citations |
---|---|---|---|
Roger Y. Tsien | 163 | 441 | 138267 |
Klaus-Robert Müller | 129 | 764 | 79391 |
Ron Kikinis | 126 | 684 | 63398 |
Ulrich S. Schubert | 122 | 2229 | 85604 |
Andreas Richter | 110 | 769 | 48262 |
Michael Böhm | 108 | 755 | 66103 |
Juan Bisquert | 107 | 450 | 46267 |
John P. Sumpter | 101 | 266 | 46184 |
Jos Lelieveld | 100 | 570 | 37657 |
Michael Schulz | 100 | 759 | 50719 |
Peter Singer | 94 | 702 | 37128 |
Charles R. Tyler | 92 | 325 | 31724 |
John P. Burrows | 90 | 815 | 36169 |
Hans-Peter Kriegel | 89 | 444 | 73932 |
Harald Haas | 85 | 750 | 34927 |