Kohn-Sham potential with discontinuity for band gap materials

We model a Kohn-Sham potential with a discontinuity at integer particle numbers derived from the GLLB approximation of Gritsenko et al. We evaluate the Kohn-Sham gap and the discontinuity to obtain the quasiparticle gap. This allows us to compare the Kohn-Sham gaps to those obtained by accurate many-body perturbation theory based optimized potential methods. In addition, the resulting quasiparticle band gap is compared to experimental gaps. In the GLLB model potential, the exchange-correlation hole is modeled using a GGA energy density and the response of the hole to density variations is evaluated by using the common-denominator approximation and homogeneous electron gas based assumptions. In our modification, we have chosen the PBEsol potential as the GGA to model the exchange hole, and add a consistent correlation potential. The method is implemented in the GPAW code, which allows efficient parallelization to study large systems. A fair agreement for Kohn-Sham and the quasiparticle band gaps with semiconductors and other band gap materials is obtained with a potential which is as fast as GGA to calculate.Comment: submitted to Physical Review

Kohn-Sham decomposition in real-time time-dependent density-functional theory: An efficient tool for analyzing plasmonic excitations

The real-time-propagation formulation of time-dependent density-functional theory (RT-TDDFT) is an efficient method for modeling the optical response of molecules and nanoparticles. Compared to the widely adopted linear-response TDDFT approaches based on, e.g., the Casida equations, RT-TDDFT appears, however, lacking efficient analysis methods. This applies in particular to a decomposition of the response in the basis of the underlying single-electron states. In this work, we overcome this limitation by developing an analysis method for obtaining the Kohn-Sham electron-hole decomposition in RT-TDDFT. We demonstrate the equivalence between the developed method and the Casida approach by a benchmark on small benzene derivatives. Then, we use the method for analyzing the plasmonic response of icosahedral silver nanoparticles up to Ag$_{561}$. Based on the analysis, we conclude that in small nanoparticles individual single-electron transitions can split the plasmon into multiple resonances due to strong single-electron-plasmon coupling whereas in larger nanoparticles a distinct plasmon resonance is formed.Comment: 11 pages, 3 figure

Many ways to Rome: Exogenous and endogenous pathways to environmental and social performance

It is often taken for granted that corporate social responsibility (CSR) will bring about social benefits and environmental improvements. Yet there is little empirical evidence of outcomes of CSR initiatives for the natural environment or the wider society as studies have focused on the influence of CSR on financial performance rather than its societal outcomes. This study begins addressing this gap in the literature by empirically studying the environmental and social performance of CSR in 19 European companies. We analyse which configurations of institutional constraints and organizational CSR practices influence environmental and social performance. Based on this analysis, we identify two pathways that can lead to high environmental and social performance and we scrutinize configurations that lead to low performance. The exogenous pathway is characterized by the use of externally certified management tools and certificates and a high importance of external rating schemes. This pathway seems typical for large publicly listed firms. The endogenous pathway, in turn, includes firms that are characterized by internally developed means of conducting CSR

”Bosniassa ei ole takeita mistään.”:Bosnia ja Hertsegovina Helsingin Sanomien pääkirjoituksissa vuosina 1992–1995

Tiivistelmä. Helsingin Sanomat oli 1990-luvulla Suomen suurin sanomalehti. Sillä oli maassa laajin määrä lukijoita, joten lehden pääkirjoituksilla ja muilla kannanotoilla voidaan sanoa olleen painoarvoa yhteiskunnallisessa keskustelussa. Toinen merkittävä tapahtuma 90-luvulla oli Jugoslavian hajoaminen ja sitä seuranneet sodat Balkanilla. Verisin näistä sodista oli Bosnian sota ja nämä konfliktit vaikuttivat merkittävästi siihen minkälainen Balkanin alue nykyään on. Tämä työ tutkii sitä miten Helsingin Sanomien pääkirjoituksissa Bosnia ja Hertsegovinan tilannetta käsiteltiin ja minkälainen toimituksen kanta sekä näkemys tähän tilanteeseen oli

Phosphorus in manure and sewage sludge more recyclable than in soluble inorganic fertilizer

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Baltic Ecological Recycling Agriculture and Society (BERAS project) - a case of Juva milk system

The aim of the study was to determine the potential, impact and prerequisites of localization and enhanced recycling in a rural food system, illustrated by the case of Juva milk. An interdisciplinary scenario based on the increase of local, organic milk to 50 % of milk comsumption was created and the sustainability was compared, on the basis of the statistics and data collected from the actors, with the present milk system

Nutrient and energy potential for sustainable biorefineries based on wastes of agrifood systems: two regional cases

The aim of our study is to identify business models and opportunities with corporate social responsibility(CSR) presented by biorefineries based on wastes and return flows of agrifood systems. Two regional cases are explored and methods for generalisation are developed

Temporal differences in gamma-hydroxybutyrate overdoses involving injecting drug users versus recreational drug users in Helsinki : a retrospective study

Peer reviewe

Prehospital Phase of the Stroke Chain of Survival : A Prospective Observational Study

Background-Few studies have discussed the emergency call and prehospital care as a continuous process to decrease the prehospital and in-hospital delays for acute stroke. To identify features associated with early hospital arrival ( Methods and Results-This was a 2-year prospective observational study. All stroke patients who were transported to the hospital by emergency medical services and received recanalization therapy were recruited for the study. For a sample of 308 patients, the stroke code was activated in 206 (67%) and high priority was used in 258 (84%) of the emergency calls. Emergency medical services transported 285 (93%) of the patients using the stroke code and 269 (87%) using high priority. In the univariate analysis, the most dominant predictors of early hospital arrival were transport using stroke code (P= 0.001) and high priority (P= 0.002) and onset-to-call (P 23.5 minutes) for both early and late-arriving patients. Conclusions-Fast emergency medical services activation and ambulance transport promoted early hospital arrival and treatment. Although patient-dependent delays still dominate the prehospital process, it should be ensured that the minutes on the scene are well spent.Peer reviewe