15 research outputs found

    Density functional theory study of the multimode Jahn-Teller effect – ground state distortion of benzene cation

    Get PDF
    The multideterminental-DFT approach performed to analyze Jahn-Teller (JT) active molecules is described. Extension of this method for the analysis of the adiabatic potential energy surfaces and the multimode JT effect is presented. Conceptually a simple model, based on the analogy between the JT distortion and reaction coordinates gives further information about microscopic origin of the JT effect. Within the harmonic approximation the JT distortion can be expressed as a linear combination of all totally symmetric normal modes in the low symmetry minimum energy conformation, which allows calculating the Intrinsic Distortion Path, IDP, exactly from the high symmetry nuclear configuration to the low symmetry energy minimum. It is possible to quantify the contribution of different normal modes to the distortion, their energy contribution to the total stabilization energy and how their contribution changes along the IDP. It is noteworthy that the results obtained by both multideterminental-DFT and IDP methods for different classes of JT active molecules are consistent and in agreement with available theoretical and experimental values. As an example, detailed description of the ground state distortion of benzene cation is given

    Large-scale patterns in community structure of benthos and fish in the Barents Sea

    Get PDF
    Biogeographical patterns have an ecological basis, but few empirical studies possess the necessary scale and resolution relevant for investigation. The Barents Sea shelf provides an ideal study area, as it is a transition area between Atlantic and Arctic regions, and is sampled by a comprehensive survey of all major functional groups. We studied spatial variation in species composition of demersal fish and benthos to elucidate how fish and benthos communities co-varied in relation to environmental variables. We applied co-correspondence analysis on presence–absence data of 64 fishes and 302 benthos taxa from 329 bottom trawl hauls taken at the Barents Sea ecosystem survey in August–September 2011. We found highly significant similarities in the spatial pattern of distribution of benthos and fishes, despite their differences in motility and other ecological traits. The first common ordination axis separated boreal species in the south-west (Atlantic temperate water) from Arctic species in the north-east (Arctic cold water, ice-covered in winter). The second common axis separated shallow bank species from species found in deep basins and trenches. Our results show that fish and benthos communities had a similar relationship to the environmental gradients at the scale of hundreds to thousands of kilometres. We further discussed how fish–benthos interactions vary between sub-regions in the Barents Sea based on species traits and a food web topology for the Barents Sea. This study forms a basis for further investigations on links between fish and benthos communities in the Barents Sea

    Gender inequality in economic resources

    No full text
    Women’s lower economic power is one of the symptoms of a hierarchical organization of societies. Creating economic gender equality needs to be a core interest of policies and research as it is a key to better well-being for other social groups and has advantages for society at large. This chapter first presents current trends in the understanding of unequal distribution of economic resources and specifically the gender pay gap based on several structural and psychological factors. It then takes a different angle on these individual differences approaches and analyzes the contributions and moderating forces in the social context which reinforce or inhibit both structural and psychological reasons for economic inequalities. Social psychological findings help to understand how stereotypes and social norms affect bias in pay allocators, the differential valuation of job content when stereotyped as feminine or masculine, and the gender variance in pay receivers’ preferences and behaviors. In the concluding remarks three contextual keys for efficient interventions are advanced aiming at changing the social reality and thereby attenuating gender bias of individuals: The increase of female representation in positions of power, combined with diversity friendly societal and organizational climates, and transparency of the distribution of economic power
    corecore