Search results for " NATURA"
showing 10 items of 34989 documents
Strictly correlated electrons approach to excitation energies of dissociating molecules
2019
In this work we consider a numerically solvable model of a two-electron diatomic molecule to study a recently proposed approximation based on the density functional theory of so-called strictly correlated electrons (SCE). We map out the full two-particle wave function for a wide range of bond distances and interaction strengths and obtain analytic results for the two-particle states and eigenenergies in various limits of strong and weak interactions, and in the limit of large bond distance. We then study the so-called Hartree-exchange-correlation (Hxc) kernel of time-dependent density functional theory which is a key ingredient in calculating excitation energies. We study an approximation b…
Board structures, liberal countries, and developed market economies. Do they matter in environmental reporting? An international outlook
2019
This is the pre-peer reviewed version of the following article: Board structures, liberal countries, and developed market economies. Do they matter in environmental reporting? An international outlook, which has been published in final form at: https://doi.org/10.1002/bse.2275. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Previous empirical evidence has shown the effect of most corporate governance mechanisms on corporate social responsibility and environmental disclosure. However, there is scant empirical evidence that examines the influence of liberal countries, developed market economies, and board s…
The associations of quantitative/qualitative job insecurity and well-being: The role of self-esteem.
2019
Job insecurity is recognized as one of the most prominent job stressors for employees. Despite decades of research, the concurrent examination of both quantitative (i.e. perceived threat of job loss) and qualitative (i.e., perceived threat of losing some job features) job insecurity and the analysis of their different relationships with well-being at work have received relatively scarce attention. This study examined a moderated mediation model of the relationship between quantitative job insecurity and well-being at work. In doing so, the focus was on the mediating effects of qualitative job insecurity and the moderating effects of self-esteem in the abovementioned relationships. Drawing f…
Search for photons with energies above 1018 eV using the hybrid detector of the Pierre Auger Observatory
2017
A search for ultra-high energy photons with energies above 1 EeV is performed using nine years of data collected by the Pierre Auger Observatory in hybrid operation mode. An unprecedented separation power between photon and hadron primaries is achieved by combining measurements of the longitudinal air-shower development with the particle content at ground measured by the fluorescence and surface detectors, respectively. Only three photon candidates at energies 1-2 EeV are found, which is compatible with the expected hadron-induced background. Upper limits on the integral flux of ultra-high energy photons of 0.027, 0.009, 0.008, 0.008 and 0.007 km-2 sr-1 yr-1 are derived at 95% C.L. for ener…
Ultra-High Energy Neutrinos at the Pierre Auger Observatory
2013
The observation of ultrahigh energy neutrinos (UHE nu s) has become a priority in experimental astroparticle physics. UHE nu s can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going nu) or in the Earth crust (Earth-skimming nu), producing air showers that can be observed with arrays of detectors at the ground. With the surface detector array of the Pierre Auger Observatory we can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after having traversed a large amount of atmosphere). In this work we review the procedure and …
Experimental Constraints on the Deep Magma Feeding System at StromboliVolcano, Italy
2009
International audience; New experiments have been performed on a high-K basalt (PST-9) from Stromboli volcano, Italy, to constrain the physical conditions of golden pumice magmas at their storage level and discuss their petrogenesis. Fluid-present, H2O- and CO2-bearing, near-liquidus experiments were performed at 11508C between 100 and 400MPa and under oxidizing conditions. Glasses were analyzed by Fourier transform IR spectroscopy and their H2O and CO2 concentrations compared with those in glass inclusions.Most glass inclusions cluster near the 200MPa isobar, suggesting entrapment at a depth of ~8 km. Golden pumice magmas have viscosities of 7.9 Pa s and densities of 2.48-2.57 g/cm3. Compo…
Ultra-high temperature metamorphism recorded in Fe-rich olivine-bearing migmatite from the Khondalite Belt, North China Craton
2018
International audience; We document the first occurrence of Fe‐rich olivine‐bearing migmatitic metapelite in the Khondalite Belt, North China Craton. Petrological analyses revealed two exotic assemblages of orthopyroxene+spinel+olivine and orthopyroxene+spinel+cordierite. Phase relation modelling suggests that these assemblages are diagnostic of ultra‐high temperature (UHT) metamorphism in the Fe‐rich system, with temperatures from 1,000 to 1,050°C at 0.6 GPa. U–Th–Pb SIMS analyses on zircon reveal a similar age of c. 1.92 Ga for the olivine‐bearing migmatite and an adjacent gabbronoritic intrusion that is therefore identified as the heat source for the UHT metamorphism. These results, coup…
Effects of UV Radiation and Diet on Polyunsaturated Fatty Acids in the Skin, Ocular Tissue and Dorsal Muscle of Atlantic Salmon (Salmo salar) Held in…
2010
Article published in Photochemistry and Photobiology, 86 (4): 909-919 JUL-AUG 2010 The effect of UV radiation (UVR) on juvenile Atlantic salmon (Salmo salar) was assessed by measuring the fatty acid (FA) profiles of muscle, dorsal and ventral skin, and ocular tissues following 4-month long exposures to four different UVR treatments in outdoor rearing tanks. Fish were fed two different diets (Anchovy- and Herring-oil based) that differed in polyunsaturated fatty acid (PUFA) concentrations. Anchovy-fed salmon had higher concentrations of ALA (alpha-linoleic acid; 18:3n-3), EPA (eicosapentaenoic acid; 20:5n-3) and DPA (docosapentaenoic acid, 22:5n-3) in their muscle tissues than fish fed the H…
Læringspotensial i en digital interaktiv matematikkundervisning : en analyse av læringspotensialet i geometriundervisningen på 8. trinn med utstrakt …
2016
Masteroppgave matematikkdidaktikk – Universitetet i Agder 2016 The theme of this master thesis is learning potential in mathematical tasks designed for geometry teaching in GeoGebra in 8th grade. This thesis is written in connection to the project Digital interactive mathematics teaching (DIM), where the goal is to create innovative mathematics teaching by using digital tools in a pedagogic context. Previous research has documented that students learning outcome of the teaching is largely influenced and limited by the tasks that are given. In this context analysis of the tasks learning potential is particular interesting. Therefore, my research question is: What learning potential is it in …
Den Virtuelle Matematikkskolen - Ungdomstrinnet : En studie av hvilke pedagogiske konsekvenser bruk av nettressursen DVM-U kan føre med seg
2016
Masteroppgave matematikkdidaktikk – Universitetet i Agder 2016 Many lower secondary school students struggle with mathematics and with motivation in the subject. To improve student achievement and motivation in mathematics, The Norwegian Centre for ICT in Education and The Norwegian Centre for Mathematics Education have developed an online learning resource that contains mathematical examples, exercises and games, called The Virtual School of Mathematics – Lower Secondary (DVM-U). The Norwegian Centre for ICT in Education suggest that DVM-U can be used in preparation of a topic, or as something students can work with if they do not benefit on a satisfactory level from the classroom teaching…