Institution
University of Hamburg
Education•Hamburg, Germany•
About: University of Hamburg is a education organization based out in Hamburg, Germany. It is known for research contribution in the topics: Population & Laser. The organization has 45564 authors who have published 89286 publications receiving 2850161 citations. The organization is also known as: Hamburg University.
Topics: Population, Laser, Transplantation, Large Hadron Collider, Higgs boson
Papers published on a yearly basis
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TL;DR: Very metal-deficient stars have been identified in the last few decades as discussed by the authors, leading to the discovery of the majority of stars with [Fe/H] < −2.0.
Abstract: ▪ Abstract We discuss the importance of very metal-poor stars to develop an understanding of the nature of the first stars that formed in the Universe and the nucleosynthesis events associated with them, as well as to refine models of galaxy formation, in particular for large spiral galaxies such as the Milky Way. After briefly reviewing the history of the search for very metal-deficient stars in the Galaxy, we summarize ongoing efforts, concentrating on the two large objective-prism surveys that have led to the discovery of the majority of stars with [Fe/H] < −2.0 known at present: the HK survey of Beers and collaborators and the Hamburg/ESO survey of Christlieb and collaborators. We then consider the wealth of information that can be gleaned from high-resolution spectroscopic study of very metal-poor stars. We close with a list of open questions and a discussion of new survey techniques that will expand the sample of recognized very metal-deficient stars in the Galaxy by several orders of magnitude.
1,173 citations
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TL;DR: In this article, a study of the clinical data and periprosthetic tissues associated with endoprostheses with a metal-on-metal articulation that had been retrieved at revision was performed.
Abstract: Background: Some patients who have a total hip replacement with a second-generation metal-on-metal articulation have persistent or early recurrence of preoperative symptoms. Characteristic histological changes in the periprosthetic tissues suggested the development of an immunological response. Therefore, in order to determine the relevance of these symptoms, we performed a study of the clinical data and periprosthetic tissues associated with endoprostheses with a metal-on metal articulation that had been retrieved at revision.
Methods: Periprosthetic tissues as well as the clinical data on the patients were obtained from the first nineteen consecutive revisions performed at the treating hospitals. At the time of the revision, fourteen patients had the metal-on-metal articulation exchanged for either an alumina-ceramic or a metal-on-polyethylene articulation. Five patients received another second-generation metal-on-metal total joint replacement. Five-micrometer sections were prepared from the tissue samples, were stained with routine and immunohistochemical methods, and were examined histologically. Histological specimens from three groups of patients, two of which were treated with non-metal-on-metal implants, served as controls.
Results: The majority of patients had persistence of their preoperative pain or early recurrence of the pain after the original total hip replacement, and often a pronounced hip joint effusion had developed after the original replacement. Radiographic follow-up showed the development of radiolucent lines in five hips and of osteolysis in another seven hips. At the revision surgery, both the cup and the stem were found to be well fixed in nine patients. The characteristic histological features were diffuse and perivascular infiltrates of T and B lymphocytes and plasma cells, high endothelial venules, massive fibrin exudation, accumulation of macrophages with droplike inclusions, and infiltrates of eosinophilic granulocytes and necrosis. Only a few metal particles were detected. Immunohistochemical analysis demonstrated that the cellular reaction was still active. The patients who received another second-generation metal-on-metal articulation at the time of the revision had no decrease in symptoms. In the control group of tissues obtained at revisions of endoprostheses without cobalt, chromium, or nickel articulations, there were no similar signs of immune reactions.
Conclusions: These histological findings support the possibility of a lymphocyte-dominated immunological response. Although the prevalence of this reaction is low, the persistence or early reappearance of symptoms, including a marked joint effusion and the development of osteolysis, after primary implantation may suggest the possibility of such a reaction.
1,172 citations
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TL;DR: The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers as discussed by the authors.
Abstract: The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers. In this paper we present full results from a search for binary black hole merger signals with total masses up to 100M⊙ and detailed implications from our observations of these systems. Our search, based on general-relativistic models of gravitational wave signals from binary black hole systems, unambiguously identified two signals, GW150914 and GW151226, with a significance of greater than 5σ over the observing period. It also identified a third possible signal, LVT151012, with substantially lower significance, which has a 87% probability of being of astrophysical origin. We provide detailed estimates of the parameters of the observed systems. Both GW150914 and GW151226 provide an unprecedented opportunity to study the two-body motion of a compact-object binary in the large velocity, highly nonlinear regime. We do not observe any deviations from general relativity, and place improved empirical bounds on several high-order post-Newtonian coefficients. From our observations we infer stellar-mass binary black hole merger rates lying in the range 9−240Gpc−3yr−1. These observations are beginning to inform astrophysical predictions of binary black hole formation rates, and indicate that future observing runs of the Advanced detector network will yield many more gravitational wave detections.
1,172 citations
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Stockholm University1, Alfred Wegener Institute for Polar and Marine Research2, University of Hamburg3, United States Geological Survey4, Northern Arizona University5, University of Florida6, University of Alaska Fairbanks7, Lawrence Berkeley National Laboratory8, National Park Service9, University of Copenhagen10, Argonne National Laboratory11, Bowdoin College12, Lehigh University13
TL;DR: In this article, the authors presented revised estimates of permafrost organic carbon stocks, including quantitative uncertainty estimates, in the 0-3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska.
Abstract: Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of permafrost SOC stocks, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. Revised estimates are based on significantly larger databases compared to previous studies. Despite this there is evidence of significant remaining regional data gaps. Estimates remain particularly poorly constrained for soils in the High Arctic region and physiographic regions with thin sedimentary overburden (mountains, highlands and plateaus) as well as for deposits below 3 m depth in deltas and the Yedoma region. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are substantial differences in other components, including the fraction of perennially frozen SOC. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 12 and 472 ± 27 Pg for the 0–0.3 and 0–1 m soil depths, respectively (±95% confidence intervals). Storage of SOC in 0–3 m of soils is estimated to 1035 ± 150 Pg. Of this, 34 ± 16 Pg C is stored in poorly developed soils of the High Arctic. Based on generalized calculations, storage of SOC below 3 m of surface soils in deltaic alluvium of major Arctic rivers is estimated as 91 ± 52 Pg. In the Yedoma region, estimated SOC stocks below 3 m depth are 181 ± 54 Pg, of which 74 ± 20 Pg is stored in intact Yedoma (late Pleistocene ice- and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits. Total estimated SOC storage for the permafrost region is ∼1300 Pg with an uncertainty range of ∼1100 to 1500 Pg. Of this, ∼500 Pg is in non-permafrost soils, seasonally thawed in the active layer or in deeper taliks, while ∼800 Pg is perennially frozen. This represents a substantial ∼300 Pg lowering of the estimated perennially frozen SOC stock compared to previous estimates.
1,168 citations
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TL;DR: The main logistics processes and operations in container terminals are described and classified and a survey of methods for their optimization is presented.
Abstract: In the last four decades the container as an essential part of a unit-load-concept has achieved undoubted importance in international sea freight transportation. With ever increasing containerization the number of seaport container terminals and competition among them have become quite remarkable. Operations are nowadays unthinkable without effective and efficient use of information technology as well as appropriate optimization (operations research) methods. In this paper we describe and classify the main logistics processes and operations in container terminals and present a survey of methods for their optimization.
1,158 citations
Authors
Showing all 46072 results
Name | H-index | Papers | Citations |
---|---|---|---|
Rudolf Jaenisch | 206 | 606 | 178436 |
Bruce M. Psaty | 181 | 1205 | 138244 |
Stefan Schreiber | 178 | 1233 | 138528 |
Chris Sander | 178 | 713 | 233287 |
Dennis J. Selkoe | 177 | 607 | 145825 |
Daniel R. Weinberger | 177 | 879 | 128450 |
Ramachandran S. Vasan | 172 | 1100 | 138108 |
Bradley Cox | 169 | 2150 | 156200 |
Anders Björklund | 165 | 769 | 84268 |
J. S. Lange | 160 | 2083 | 145919 |
Hannes Jung | 159 | 2069 | 125069 |
Andrew D. Hamilton | 151 | 1334 | 105439 |
Jongmin Lee | 150 | 2257 | 134772 |
Teresa Lenz | 150 | 1718 | 114725 |
Stefanie Dimmeler | 147 | 574 | 81658 |