Stockholm University

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

Social-ecological resilience: insights and issues for planning theory

Abstract: With its origins in systems ecology and emerging interest in the inter-disciplinary examination of the governance of linked social-ecological systems, social-ecological resilience offers a field of ...

Does job insecurity lead to impaired well-being or vice versa? Estimation of cross-lagged effects using latent variable modelling

Abstract: Although research suggests that job insecurity is associated with impaired employee well-being, there is insufficient empirical evidence to draw any causal inferences since most studies are cross-sectional and thus do not control for previous levels of health symptoms. We used longitudinal questionnaire data to investigate the direction of the relationship between job insecurity and health complaints. After controlling for prior levels of mental and physical health complaints and five other variables that could potentially confound the results (gender, age, organizational tenure, family status, and education), the results of latent variable modelling showed that the cross-lagged effect of job insecurity on mental health complaints, one year later, was significant whereas the reversed effects of mental and physical health complaints on subsequent insecurity were non-significant. However, there was no significant cross-lagged effect of job insecurity on physical health complaints. The results provide empirical support for the theoretical notion that job insecurity leads to health complaints, and imply that prior levels of health should be taken into consideration in order to explain the relative effect of perceived job insecurity on the physical and mental health of the workforce. Copyright © 2003 John Wiley & Sons, Ltd.

Shared Molecular Mechanisms of Membrane Transporters

Abstract: The determination of the crystal structures of small-molecule transporters has shed light on the conformational changes that take place during structural isomerization from outward- to inward-facing states. Rather than using a simple rocking movement of two bundles around a central substrate-binding site, it has become clear that even the most simplistic transporters utilize rearrangements of nonrigid bodies. In the most dramatic cases, one bundle is fixed while the other, structurally divergent, bundle carries the substrate some 18 A across the membrane, which in this review is termed an elevator alternating-access mechanism. Here, we compare and contrast rocker-switch, rocking-bundle, and elevator alternating-access mechanisms to highlight shared features and novel refinements to the basic alternating-access model.

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

Abstract: The applications of exchange coupled bi-magnetic hard/soft and soft/hard ferromagnetic core/shell nanoparticles are reviewed. After a brief description of the main synthesis approaches and the core/shell structural-morphological characterization, the basic static and dynamic magnetic properties are presented. Five different types of perspective applications, based on diverse patents and research articles, are described: permanent magnets, recording media, microwave absorption, biomedical applications and other applications. Both the advantages of the core/shell morphology and some of the remaining challenges are discussed.

Overview of the international project on biogenic aerosol formation in the boreal forest (BIOFOR)

Abstract: Aerosol formation and subsequent particle growth in ambient air have been frequently observed at a boreal forest site (SMEAR II station) in Southern Finland. The EU funded project BIOFOR (Biogenic aerosol formation in the boreal forest) has focused on: (a) determination of formation mechanisms of aerosol particles in the boreal forest site; (b) verification of emissions of secondary organic aerosols from the boreal forest site; and (c) quantification of the amount of condensable vapours produced in photochemical reactions of biogenic volatile organic compounds (BVOC) leading to aerosol formation. The approach of the project was to combine the continuous measurements with a number of intensive field studies. These field studies were organised in three periods, two of which were during the most intense particle production season and one during a non-event season. Although the exact formation route for 3 nm particles remains unclear, the results can be summarised as follows: Nucleation was always connected to Arctic or Polar air advecting over the site, giving conditions for a stable nocturnal boundary layer followed by a rapid formation and growth of a turbulent convective mixed layer closely followed by formation of new particles. The nucleation seems to occur in the mixed layer or entrainment zone. However two more prerequisites seem to be necessary. A certain threshold of high enough sulphuric acid and ammonia concentrations is probably needed as the number of newly formed particles was correlated with the product of the sulphuric acid production and the ammonia concentrations. No such correlation was found with the oxidation products of terpenes. The condensation sink, i.e., effective particle area, is probably of importance as no nucleation was observed at high values of the condensation sink. From measurement of the hygroscopic properties of the nucleation particles it was found that inorganic compounds and hygroscopic organic compounds contributed both to the particle growth during daytime while at night time organic compounds dominated. Emissions rates for several gaseous compounds was determined. Using four independent ways to estimate the amount of the condensable vapour needed for observed growth of aerosol particles we get an estimate of 2–10×10 7 vapour molecules cm −3 . The estimations for source rate give 7.5–11×10 4 cm −3 s −1 . These results lead to the following conclusions: The most probable formation mechanism is ternary nucleation (water-sulphuric acid-ammonia). After nucleation, growth into observable sizes (∼3 nm) is required before new particles appear. The major part of this growth is probably due to condensation of organic vapours. However, there is lack of direct proof of this phenomenon because the composition of 1–5 nm size particles is extremely difficult to determine using the present state-of-art instrumentation DOI: 10.1034/j.1600-0889.2001.530402.x