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Institution

Stockholm University

EducationStockholm, Sweden
About: Stockholm University is a education organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Supernova. The organization has 21052 authors who have published 62567 publications receiving 2725859 citations. The organization is also known as: University of Stockholm & Stockholms universitet.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors used tree-ring chronologies from the Russian Altai and European Alps to reconstruct summer temperatures over the past two millennia and found an unprecedented, longlasting and spatially synchronized cooling following a cluster of large volcanic eruptions in 536, 540 and 547 AD.
Abstract: Societal upheaval occurred across Eurasia in the sixth and seventh centuries. Tree-ring reconstructions suggest a period of pronounced cooling during this time associated with several volcanic eruptions. Climatic changes during the first half of the Common Era have been suggested to play a role in societal reorganizations in Europe1,2 and Asia3,4. In particular, the sixth century coincides with rising and falling civilizations1,2,3,4,5,6, pandemics7,8, human migration and political turmoil8,9,10,11,12,13. Our understanding of the magnitude and spatial extent as well as the possible causes and concurrences of climate change during this period is, however, still limited. Here we use tree-ring chronologies from the Russian Altai and European Alps to reconstruct summer temperatures over the past two millennia. We find an unprecedented, long-lasting and spatially synchronized cooling following a cluster of large volcanic eruptions in 536, 540 and 547 AD (ref. 14), which was probably sustained by ocean and sea-ice feedbacks15,16, as well as a solar minimum17. We thus identify the interval from 536 to about 660 AD as the Late Antique Little Ice Age. Spanning most of the Northern Hemisphere, we suggest that this cold phase be considered as an additional environmental factor contributing to the establishment of the Justinian plague7,8, transformation of the eastern Roman Empire and collapse of the Sasanian Empire1,2,5, movements out of the Asian steppe and Arabian Peninsula8,11,12, spread of Slavic-speaking peoples9,10 and political upheavals in China13.

527 citations

Journal ArticleDOI
TL;DR: In this article, the degradation of coral reefs is often associated with changes in community structure where macroalgae become the dominant benthic life form, and these phase shifts can be difficult to reverse.
Abstract: Degradation of coral reefs is often associated with changes in community structure where macroalgae become the dominant benthic life form. These phase shifts can be difficult to reverse. The debate ...

526 citations

Journal ArticleDOI
TL;DR: It is argued that urban governance need to harness social networks of urban innovation to sustain ecosystem services, while nurturing discourses that situate the city as part of regional ecosystems.
Abstract: Urbanization is a global multidimensional process paired with increasing uncertainty due to climate change, migration of people, and changes in the capacity to sustain ecosystem services. This article lays a foundation for discussing transitions in urban governance, which enable cities to navigate change, build capacity to withstand shocks, and use experimentation and innovation in face of uncertainty. Using the three concrete case cities—New Orleans, Cape Town, and Phoenix—the article analyzes thresholds and cross-scale interactions, and expands the scale at which urban resilience has been discussed by integrating the idea from geography that cities form part of “system of cities” (i.e., they cannot be seen as single entities). Based on this, the article argues that urban governance need to harness social networks of urban innovation to sustain ecosystem services, while nurturing discourses that situate the city as part of regional ecosystems. The article broadens the discussion on urban resilience while challenging resilience theory when addressing human-dominated ecosystems. Practical examples of harnessing urban innovation are presented, paired with an agenda for research and policy.

526 citations

Journal ArticleDOI
TL;DR: In this paper, a fine columnar sub-grain structure of size 0.5μm was observed inside each individual large grain of single-crystal nature and with grain sizes in the range of 10-100μm.
Abstract: Laser melting (LM), with a focused Nd: YAG laser beam, was used to form solid bodies from a 316L austenite stainless steel powder. The microstructure, phase content and texture of the LM stainless steel were characterized and compared with conventional 316L stainless steel. The crack-free LM samples achieved a relative density of 98.6±0.1%. The XRD pattern revealed a single phase Austenite with preferential crystallite growth along the (100) plane and an orientation degree of 0.84 on the building surface. A fine columnar sub-grain structure of size 0.5 μm was observed inside each individual large grain of single-crystal nature and with grain sizes in the range of 10–100 μm. Molybdenum was found to be enriched at the sub-grain boundaries accompanied with high dislocation concentrations. It was proposed that such a sub-grain structure is formed by the compositional fluctuation due to the slow kinetics of homogeneous alloying of large Mo atoms during rapid solidification. The local enrichment of misplaced Mo in the Austenite lattice induced a network of dislocation tangling, which would retard or even block the migration of newly formed dislocations under indentation force, turning otherwise a soft Austenite to hardened steel. In addition, local formation of spherical nano-inclusions of an amorphous chromium-containing silicate was observed. The origin and the implications of the formation of such oxide nano-inclusions were discussed.

526 citations

Journal ArticleDOI
TL;DR: In this paper, the time-dependent climate response to changing concentrations of greenhouse gases and sulfate aerosols is studied using a coupled general circulation model of the atmosphere and the ocean (ECHAM4/OPYC3).
Abstract: The time-dependent climate response to changing concentrations of greenhouse gases and sulfate aerosols is studied using a coupled general circulation model of the atmosphere and the ocean (ECHAM4/OPYC3). The concentrations of the well-mixed greenhouse gases like CO2, CH4, N2O, and CFCs are prescribed for the past (1860–1990) and projected into the future according to International Panel on Climate Change (IPCC) scenario IS92a. In addition, the space–time distribution of tropospheric ozone is prescribed, and the tropospheric sulfur cycle is calculated within the coupled model using sulfur emissions of the past and projected into the future (IS92a). The radiative impact of the aerosols is considered via both the direct and the indirect (i.e., through cloud albedo) effect. It is shown that the simulated trend in sulfate deposition since the end of the last century is broadly consistent with ice core measurements, and the calculated radiative forcings from preindustrial to present time are within th...

526 citations


Authors

Showing all 21326 results

NameH-indexPapersCitations
Hongjie Dai197570182579
Hyun-Chul Kim1764076183227
Richard S. Ellis169882136011
Stanley B. Prusiner16874597528
Anders Björklund16576984268
Yang Yang1642704144071
Tomas Hökfelt158103395979
Bengt Winblad1531240101064
Zhenwei Yang150956109344
Marvin Johnson1491827119520
Jan-Åke Gustafsson147105898804
Markus Ackermann14661071071
Hans-Olov Adami14590883473
Markku Kulmala142148785179
Kjell Fuxe142147989846
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023158
2022537
20213,664
20203,602
20193,347
20183,092