Stockholm University

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.

Searching for dark matter annihilation in recently discovered Milky Way Satellites with Fermi-LAT

Abstract: We search for excess gamma-ray emission coincident with the positions of confirmed and candidate Milky Way satellite galaxies using six years of data from the Fermi Large Area Telescope (LAT). Our sample of 45 stellar systems includes 28 kinematically confirmed dark-matter-dominated dwarf spheroidal galaxies (dSphs) and 17 recently discovered systems that have photometric characteristics consistent with the population of known dSphs. For each of these targets, the relative predicted gamma-ray flux due to dark matter annihilation is taken from kinematic analysis if available, and estimated from a distance-based scaling relation otherwise, assuming that the stellar systems are DM-dominated dSphs. LAT data coincident with four of the newly discovered targets show a slight preference (each ~ 2sigma local) for gamma-ray emission in excess of the background. However, the ensemble of derived gamma-ray flux upper limits for individual targets is consistent with the expectation from analyzing random blank-sky regions, and a combined analysis of the population of stellar systems yields no globally significant excess (global significance < 1sigma ). Our analysis has increased sensitivity compared to the analysis of 15 confirmed dSphs by Ackermann et al. The observed constraints on the DM annihilation cross section are statistically consistent with the background expectation, improving by a factor of ~2 for large DM masses ({m}{DM,b\bar{b}}≳ 1 {TeV} and {m}{DM,{tau }+{tau }-}≳ 70 {GeV}) and weakening by a factor of ~1.5 at lower masses relative to previously observed limits.

Likelihood-based cointegration tests in heterogeneous panels

Abstract: Summary This paper presents a maximum likelihood panel test of the cointegrating rank in heterogeneous panel models based on the mean of the individual rank trace statistics. The existence of the first two moments of the asymptotic distribution of the individual trace statistic is established. Based on this, the asymptotic distribution of the test statistic is shown to be normal. The small-sample size and power properties are investigated using Monte Carlo simulations. An empirical example for a consumption model including consumption, income and inflation is estimated for 23 OECD countries over the period 1960-1994. The results indicate that two cointegrating relations exist in the system: one containing consumption and income and one inflation only.

Power Resources and Employer-Centered Approaches in Explanations of Welfare States and Varieties of Capitalism: Protagonists, Consenters, and Antagonists

Abstract: The power resources approach, underlining the relevance of socioeconomic class and partisan politics in distributive conflict within capitalist economies, is challenged by employer-centered approaches claiming employers and cross-class alliances to have been crucial in advancing the development of welfare states and varieties of capitalism. Theoretically and empirically these claims are problematic. In welfare state expansion, employers have often been antagonists, under specific conditions consenters, but very rarely protagonists. Well-developed welfare states and coordinated market economies have emerged in countries with strong left parties in long-term cabinet participation or in countries with state corporatist institutional traditions and confessional parties in intensive competition with left parties.