Frustrated quantum Ising spins simulated by spinless bosons in a tilted lattice: from a quantum liquid to antiferromagnetic order

We study spinless bosons in a decorated square lattice with a near-diagonal tilt. The resonant subspace of the tilted Mott insulator is described by an effective Hamiltonian of frustrated quantum Ising spins on a non-bipartite lattice. This generalizes an earlier proposal for the unfrustrated quantum Ising model in one dimension which was realized in a recent experiment on ultracold $^{87}$Rb atoms in an optical lattice. Very close to diagonal tilt, we find a quantum liquid state which is continuously connected to the paramagnet. Frustration can be reduced by increasing the tilt angle away from the diagonal, and the system undergoes a transition to an antiferromagnetically ordered state. Using quantum Monte Carlo simulations and exact diagonalization, we find that for realistic system sizes the antiferromagnetic order appears to be quasi-one-dimensional; however, in the thermodynamic limit the order is two-dimensional.Comment: 27 pages, 14 figure

Correction to: Biometric technology in "no-gate border crossing solutions" under consideration of privacy, ethical, regulatory and social acceptance

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Schule und Migration: Einblicke in die Praxis des interkulturellen Lernens

'Die Wiener Gesellschaft ist geprägt von kultureller und sprachlicher Vielfalt, die auch Einzug in die Klassenzimmer gefunden hat. Die Etablierung von 'Interkulturellem Lernen' als Unterrichtsprinzip ist eine Reaktion darauf. Ein ethnologisches Forscherinnen-Team ist der Frage nachgegangen, wie LehrerInnen in Wien über interkulturelles Lernen denken und wie sie es im Schulalltag umsetzen. Es zeigte sich, dass kulturelle Vielfalt und Mehrsprachigkeit oft als Störfaktor und weniger als wertvolle (Wissens-)Kompetenz und Bereicherung betrachtet werden. Eine praktische Umsetzung gestaltet sich insofern schwierig, weil sowohl in der LehrerInnen-Ausbildung die Vermittlung interkultureller Kompetenzen als auch eine konkrete Ausformulierung von Inhalten und eine Zielorientierung des Unterrichtsprinzips 'Interkulturelles Lernen' fehlen. Dieser Beitrag bietet Ansätze für LehrerInnen, wie interkulturelles Lernen praktikabler und zugänglicher gemacht werden kann.' (Autorenreferat

Interkulturelles Lernen aus ethnologischer Perspektive

Das Unterrichtsprinzip Interkulturelles Lernen kann dazu beitragen migrationsbedingten Anforderungen mit einer gewissen Kreativität zu begegnen, der Kreativität Raum zu verschaffen oder aber auch Konfliktpotentiale auszuloten und etwaige Hürden zu überwinden

Flüchtlingsforschung: sozialanthropologische Ansätze und genderspezifische Aspekte

'In diesem Artikel werden relevante Ergebnisse der gegenwärtigen Flüchtlingsforschung als spezieller Teilbereich der Globalisierungs- und Migrationsforschung vorgestellt. Dabei werden zwei Schwerpunkte gesetzt: Zum einen wird die These vertreten, dass insbesondere die sozial- und kulturanthropologische Forschung das Klischee von Flüchtlingen als 'passive HilfsempfängerInnen' durchbrochen und auf die wesentliche Bedeutung eines Aktiv-Seins für Menschen während und nach der Flucht hingewiesen hat. Zum anderen werden frauenspezifische Fluchtgründe und die Anerkennung von frauenspezifischen Verfolgungsformen erläutert. Abschließend werden genderspezifische Aspekte mit Fallbeispielen aus empirischen Studien der beiden Autorinnen näher ausgeführt.' (Autorenreferat)'In the context of research about globalisation and migration, this article presents crucial results of refugee studies. Two aspects are covered: social and cultural anthropology help deconstructing the image of refugees as helpless and passive aid receivers, and emphasize the need for an active role of refugees during and after their flight. The gender specific reasons that produce refugees and also gender specific forms of persecution are discussed in detail. Finally, case studies, carried out by the two authors, exemplify these gender issues.' (author's abstract)

counterfactuals: An R Package for Counterfactual Explanation Methods

Counterfactual explanation methods provide information on how feature values of individual observations must be changed to obtain a desired prediction. Despite the increasing amount of proposed methods in research, only a few implementations exist whose interfaces and requirements vary widely. In this work, we introduce the counterfactuals R package, which provides a modular and unified R6-based interface for counterfactual explanation methods. We implemented three existing counterfactual explanation methods and propose some optional methodological extensions to generalize these methods to different scenarios and to make them more comparable. We explain the structure and workflow of the package using real use cases and show how to integrate additional counterfactual explanation methods into the package. In addition, we compared the implemented methods for a variety of models and datasets with regard to the quality of their counterfactual explanations and their runtime behavior

The role of leptomeningeal collaterals in redistributing blood flow during stroke

Leptomeningeal collaterals (LMCs) connect the main cerebral arteries and provide alternative pathways for blood flow during ischaemic stroke. This is beneficial for reducing infarct size and reperfusion success after treatment. However, a better understanding of how LMCs affect blood flow distribution is indispensable to improve therapeutic strategies. Here, we present a novel in silico approach that incorporates case-specific in vivo data into a computational model to simulate blood flow in large semi-realistic microvascular networks from two different mouse strains, characterised by having many and almost no LMCs between middle and anterior cerebral artery (MCA, ACA) territories. This framework is unique because our simulations are directly aligned with in vivo data. Moreover, it allows us to analyse perfusion characteristics quantitatively across all vessel types and for networks with no, few and many LMCs. We show that the occlusion of the MCA directly caused a redistribution of blood that was characterised by increased flow in LMCs. Interestingly, the improved perfusion of MCA-sided microvessels after dilating LMCs came at the cost of a reduced blood supply in other brain areas. This effect was enhanced in regions close to the watershed line and when the number of LMCs was increased. Additional dilations of surface and penetrating arteries after stroke improved perfusion across the entire vasculature and partially recovered flow in the obstructed region, especially in networks with many LMCs, which further underlines the role of LMCs during stroke

The role of leptomeningeal collaterals in redistributing blood flow during stroke.

Leptomeningeal collaterals (LMCs) connect the main cerebral arteries and provide alternative pathways for blood flow during ischaemic stroke. This is beneficial for reducing infarct size and reperfusion success after treatment. However, a better understanding of how LMCs affect blood flow distribution is indispensable to improve therapeutic strategies. Here, we present a novel in silico approach that incorporates case-specific in vivo data into a computational model to simulate blood flow in large semi-realistic microvascular networks from two different mouse strains, characterised by having many and almost no LMCs between middle and anterior cerebral artery (MCA, ACA) territories. This framework is unique because our simulations are directly aligned with in vivo data. Moreover, it allows us to analyse perfusion characteristics quantitatively across all vessel types and for networks with no, few and many LMCs. We show that the occlusion of the MCA directly caused a redistribution of blood that was characterised by increased flow in LMCs. Interestingly, the improved perfusion of MCA-sided microvessels after dilating LMCs came at the cost of a reduced blood supply in other brain areas. This effect was enhanced in regions close to the watershed line and when the number of LMCs was increased. Additional dilations of surface and penetrating arteries after stroke improved perfusion across the entire vasculature and partially recovered flow in the obstructed region, especially in networks with many LMCs, which further underlines the role of LMCs during stroke