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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 model the incentives of the media to deliver news to different groups and predict that this change should raise spending on government programmes used by poor and rural voters.
Abstract: If better informed voters receive favourable policies, then mass media will affect policy because mass media provide most of the information people use in voting. This paper models the incentives of the media to deliver news to different groups. The increasing-returns-to-scale technology and advertising financing of media firms induce them to provide more news to large groups, such as taxpayers and dispersed consumer interests, and groups that are valuable to advertisers. This news bias alters the tradeoff in political competition and therefore introduces a bias in public policy. The paper also discusses the effects of broadcast media replacing newspapers as the main information source about politics. The model predicts that this change should raise spending on government programmes used by poor and rural voters.

451 citations

Journal ArticleDOI
TL;DR: In this article, a model of ocean and sediment geochemistry is used to evaluate the current proposals for explaining the glacial/interglacial pCO2 cycles within the context of the ocean carbon cycle.
Abstract: Fifteen years after the discovery of major glacial/interglacial cycles in the CO2 concentration of the atmosphere, it seems that all of the simple mechanisms for lowering pCO2 have been eliminated. We use a model of ocean and sediment geochemistry, which in- cludes new developments of iron limitation of biological production at the sea surface and anoxic diagenesis and its effect on CaCO3 preservation in the sediments, to evaluate the current proposals for explaining the glacial/ interglacial pCO2 cycles within the context of the ocean carbon cycle. After equilibration with CaCO3 the model is unable to generate glacial pCO2 by increasing ocean NO3 but predicts that a doubling of ocean H4SiO4 might suffice. However, the model is unable to generate a doubling of ocean H4SiO4 by any reasonable changes in SiO2 weathering or production. Our conclusions force us to challenge one or more of the assumptions at the foundations of chemical oceanography. We can abandon the stability of the "Redfield ratio" of nitrogen to phos- phorus in living marine phytoplankton and the ultimate limitation of marine photosynthesis by phosphorus. We can challenge the idea that the pH of the deep ocean is held relatively invariant by equilibrium with CaCO3 .A third possibility, which challenges physical oceanogra- phers, is that diapycnal mixing in ocean circulation mod- els exceeds the rate of mixing in the real ocean, dimin- ishing the model pCO2 sensitivity to biological carbon uptake.

450 citations

Journal ArticleDOI
19 Jan 2001-Science
TL;DR: In this paper, the mtDNA control region sequences of 191 domestic horses were analyzed and found a high diversity of matrilines, which implies an unprecedented and widespread integration of mtrilines and an extensive utilization and taming of wild horses.
Abstract: Domestication entails control of wild species and is generally regarded as a complex process confined to a restricted area and culture. Previous DNA sequence analyses of several domestic species have suggested only a limited number of origination events. We analyzed mitochondrial DNA (mtDNA) control region sequences of 191 domestic horses and found a high diversity of matrilines. Sequence analysis of equids from archaeological sites and late Pleistocene deposits showed that this diversity was not due to an accelerated mutation rate or an ancient domestication event. Consequently, high mtDNA sequence diversity of horses implies an unprecedented and widespread integration of matrilines and an extensive utilization and taming of wild horses. However, genetic variation at nuclear markers is partitioned among horse breeds and may reflect sex-biased dispersal and breeding.

449 citations

Journal ArticleDOI
R. Adam1, Nabila Aghanim2, M. Ashdown3, J. Aumont2  +218 moreInstitutions (58)
TL;DR: In this paper, the authors investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data and find that the universe is ionized at less than the 10% level at redshifts above z ≃ 10.8.
Abstract: We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058 ± 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric or an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Δz < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z ≃ 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. We show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.

449 citations

Journal ArticleDOI
Marco Ajello1, Andrea Albert2, W. B. Atwood3, Guido Barbiellini4  +155 moreInstitutions (45)
TL;DR: The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of the emission toward the Galactic center (GC) in high-energy gamma-rays as mentioned in this paper.
Abstract: The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of the emission toward the Galactic center (GC) in high-energy gamma-rays. This paper describes the analysis of data ...

448 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