The asymmetric single-impurity Anderson model - the modified perturbation theory

We investigate the single-impurity Anderson model by means of the recently introduced modified perturbation theory. This approximation scheme yields reasonable results away from the symmetric case. The agreement with exactly known results for the symmetric case is checked, and results for the non-symmetric case are presented. With decreasing conduction band occupation, the breakdown of the screening of the local moment is observed. In the crossover regime between Kondo limit and mixed-valence regime, an enhanced zero-temperature susceptibility is found.Comment: 7 pages, 7 figures, to appear in Physica

Fenomenologins möjligheter i etnologin: Rapport från en nationell workshop.

Fredag den 17 december 2010 genomfördes en nationell workshop kring fenomenologins vara i etnologin vid Institutionen för kulturvetenskaper, Lunds universitet. Denna rapport är ett resultat från workshopen och skall ses som ett försök att intensifiera den diskussion som var på workshopen. Etnologin har tagit inspiration från fenomenologin och i denna filosofi har ämnet funnit teorier och metodologier för att utveckla kulturanalysen. Ibland har inspirationen kommit från de fenomenologiska klassikerna - Martin Heidegger, Maurice Merleau-Ponty, Simone de Beauvoir – andra gånger har inspirationen varit antropologer och sociologer som har varit starkt färgade av fenomenologin. Idag vågar vi påstå att det finns en så stor etnologisk diskussion och användning av denna filosofi att vi kan prata om en etnologisk tolkning av fenomenologi

Climatic controls on the survival and loss of ancient types of barley on North Atlantic Islands

This study was partly funded by a Scottish Government Rural and Environment Science and Analytical Service award (PM, JW and TSG). The Scottish Northern Cairngorms reconstruction was finalised through the project NERC project ‘SCOT2K: Reconstructing 2000 years of Scottish climate from tree rings (NE/ K003097/1)’ while the new central and northwest Scottish data were developed as part of a NERC Iapetus PhD project.For ancient types of barley at sites in the Scottish Isles, Faroes, and Iceland, we calculated minimum temperature requirements for grain production (grain production threshold, GPT) as accumulated degree days over the cropping season. Site suitability for barley from AD 1200 to 2000 was investigated by comparing these thresholds with reconstructions of annual cropping season degree days (CSDD) using temperature and tree-ring data. In Iceland, between AD 1200 and 1500, reconstructed CSDD were more favorable in the southwest (Reykjavik), with fewer years below the GPT, than in the North, East and West, but there were two periods (1340–1389 and 1426–1475) with low average CSDD and several years below the GPT which possibly influenced the abandonment of barley cultivation around this time. Reconstructed CSDD for the Faroes (Tórshavn) had only one year below the GPT, but 15 periods of four or more consecutive years with low CSDD which would have challenged barley cultivation, especially in the thirteenth century. Reconstructed CSDD were highest for the Scottish Isles, allowing a more prominent role of barley in the farming system and economy. Nevertheless, years with poor harvests or famines were common and about half were associated with low CSDD, resulting in a significant temperature link but also demonstrating the important contribution of other factors. Despite frequent unfavorable years in both the Faroes and Scottish Isles, resilient production systems, well-adapted barley strains and socio-economic factors allowed barley cultivation to continue, and some ancient types to survive to the present day.Publisher PDFPeer reviewe

Electronic structure of undoped and potassium doped coronene investigated by electron energy-loss spectroscopy

We performed electron energy-loss spectroscopy studies in transmission in order to obtain insight into the electronic properties of potassium intercalated coronene, a recently discovered superconductor with a rather high transition temperature of about 15\,K. A comparison of the loss function of undoped and potassium intercalated coronene shows the appearance of several new peaks in the optical gap upon potassium addition. Furthermore, our core level excitation data clearly signal filling of the conduction bands with electrons.Comment: 15 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1102.328

Potentials, challenges and visions for future European organic animal farming

There is a serious need for significant and fundamental improvements to the way we currently produce and consume food if we are going to respond meaningfully to the enormous global environmental challenges that face us. The role of animal farming in particular is faced with the challenge of balancing their potential positive contribution to our food system within an effective circular economy while ensuring that the animals on our farms exist as living, sentient beings that are treated in ways that allow their lives, from their perspective, to be worth living

Glutamate-system defects behind psychiatric manifestations in a familial hemiplegic migraine type 2 disease-mutation mouse model

Migraine is a complex brain disorder, and understanding the complexity of this prevalent disease could improve quality of life for millions of people. Familial Hemiplegic Migraine type 2 (FHM2) is a subtype of migraine with aura and co-morbidities like epilepsy/seizures, cognitive impairments and psychiatric manifestations, such as obsessive-compulsive disorder (OCD). FHM2 disease-mutations locate to the ATP1A2 gene encoding the astrocyte-located α(2)-isoform of the sodium-potassium pump (α(2)Na(+)/K(+)-ATPase). We show that knock-in mice heterozygous for the FHM2-associated G301R-mutation (α(2)(+/G301R)) phenocopy several FHM2-relevant disease traits e.g., by mimicking mood depression and OCD. In vitro studies showed impaired glutamate uptake in hippocampal mixed astrocyte-neuron cultures from α(2)(G301R/G301R) E17 embryonic mice, and moreover, induction of cortical spreading depression (CSD) resulted in reduced recovery in α(2)(+/G301R) male mice. Moreover, NMDA-type glutamate receptor antagonists or progestin-only treatment reverted specific α(2)(+/G301R) behavioral phenotypes. Our findings demonstrate that studies of an in vivo relevant FHM2 disease knock-in mouse model provide a link between the female sex hormone cycle and the glutamate system and a link to co-morbid psychiatric manifestations of FHM2

Strategies And Visions For The Future Of Organic Animal Farming

Based on existing knowledge and current research projects, a number of innovative strategies and approaches are proposed that would enable organic animal farming to contribute to a more sustainable and resilient food systems that also impacts positively on our surrounding socio-ecological landscape. The focus is on 1) integrated, multispecies, diversified systems, 2) sustainable foraging strategies and efficient utilisation of natural resources, 3) home grown protein feed especially for monogastric animals, 4) resilience as the core of health development rather than just freedom of diseases, 5) breeding including multipurpose breeds, and 6) enhanced mother-infant contact

Energy gap in superconducting fullerides: optical and tunneling studies

Tunneling and optical transmission studies have been performed on superconducting samples of Rb3C60. At temperatures much below the superconducting transition temperature Tc the energy gap is 2 Delta=5.2 +- 0.2meV, corresponding to 2 Delta/kB Tc = 4.2. The low temperature density of states, and the temperature dependence of the optical conductivity resembles the BCS behavior, although there is an enhanced ``normal state" contribution. The results indicate that this fulleride material is an s-wave superconductor, but the superconductivity cannot be described in the weak coupling limit.Comment: RevTex file with four .EPS figures. Prints to four pages. Also available at http://buckminster.physics.sunysb.edu/papers/pubrece.htm

Multilocus ISSR Markers Reveal Two Major Genetic Groups in Spanish and South African Populations of the Grapevine Fungal Pathogen Cadophora luteo-olivacea

Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied. Inter-simple-sequence repeat-polymerase chain reaction (ISSR-PCR) generated 55 polymorphic loci from four ISSR primers selected from an initial screen of 13 ISSR primers. The ISSR markers revealed 40 multilocus genotypes (MLGs) in the global population. Minimum spanning network analysis showed that the MLGs from South Africa clustered around the most frequent genotype, while the genotypes from Spain were distributed all across the network. Principal component analysis and dendrograms based on genetic distance and bootstrapping identified two highly differentiated genetic clusters in the Spanish and South African C. luteo-olivacea populations, with no intermediate genotypes between these clusters. Movement within the Spanish provinces may have occurred repeatedly given the frequent retrieval of the same genotype in distant locations. The results obtained in this study provide new insights into the population genetic structure of C. luteo-olivacea in Spain and highlights the need to produce healthy and quality planting material in grapevine nurseries to avoid the spread of this fungus throughout different grape growing regions