A numerical study of the formation of magnetisation plateaus in quasi one-dimensional spin-1/2 Heisenberg models

We study the magnetisation process of the one dimensional spin-1/2 antiferromagnetic Heisenberg model with modulated couplings over j=1,2,3 sites. It turns out that the evolution of magnetisation plateaus depends on j and on the wave number q of the modulation according to the rule of Oshikawa, et al. A mapping of two- and three-leg zig-zag ladders on one dimensional systems with modulated couplings yields predictions for the occurence of magnetization plateaus. The latter are tested by numerical computations with the DMRG algorithm.Comment: 7 pages, 10 figures, accepted for publication in Euro. Phys. J.

Youths, elders, and the wages of war in Enga province, Papua New Guinea

"Here I will consider cycles of Enga warfare within the 350-year span for which we have information on warfare from oral and written historical records. The first is a period of intensive warfare that occurred in the first half of the 19th century, redrawing the map of Enga after the introduction of the sweet potato. These turbulent times were followed by a hundred-year period of successful initiatives to keep warfare in check and to promote prosperity. The Colonial Era then intervened with a ban on warfare. The second is a period of devastating “modern” warfare that began a few years before Independence in 1975 (Gordon and Kipilan 1982); Paney 1973) and accelerated in 1990 with the adoption of new technology in warfare, homemade shotguns and high-powered weapons, reversing the power hierarchy between older men and youths. Fieldwork and village court records allow us to trace the rise in violence, the formation of warring gangs of mercenaries, the impact on the population of Enga and the state of Papua New Guinea, and in the last few years, what may be a trend back towards moderation ..." - page 1AusAI

The roles of Eu during the growth of eutectic Si in Al-Si alloys

Controlling the growth of eutectic Si and thereby modifying the eutectic Si from flake-like to fibrous is a key factor in improving the properties of Al-Si alloys. To date, it is generally accepted that the impurity-induced twinning (IIT) mechanism and the twin plane re-entrant edge (TPRE) mechanism as well as poisoning of the TPRE mechanism are valid under certain conditions. However, IIT, TPRE or poisoning of the TPRE mechanism cannot be used to interpret all observations. Here, we report an atomic-scale experimental and theoretical investigation on the roles of Eu during the growth of eutectic Si in Al-Si alloys. Both experimental and theoretical investigations reveal three different roles: (i) the adsorption at the intersection of Si facets, inducing IIT mechanism, (ii) the adsorption at the twin plane re-entrant edge, inducing TPRE mechanism or poisoning of the TPRE mechanism, and (iii) the segregation ahead of the growing Si twins, inducing a solute entrainment within eutectic Si. This investigation not only demonstrates a direct experimental support to the well-accepted poisoning of the TPRE and IIT mechanisms, but also provides a full picture about the roles of Eu atoms during the growth of eutectic Si, including the solute entrainment within eutectic Si

Core hole-electron correlation in coherently coupled molecules

We study the core hole-electron correlation in coherently coupled molecules by energy dispersive near edge X-ray absorption fine-structure spectroscopy. In a transient phase, which exists during the transition between two bulk arrangements, 1,4,5,8-naphthalene-tetracarboxylicacid-dianhydride multilayer films exhibit peculiar changes of the line shape and energy position of the X-ray absorption signal at the C K-edge with respect to the bulk and gas phase spectra. By a comparison to a theoretical model based on a coupling of transition dipoles, which is established for optical absorption, we demonstrate that the observed spectroscopic differences can be explained by an intermolecular delocalized core hole-electron pair. By applying this model we can furthermore quantify the coherence length of the delocalized core-exciton.Comment: 5 pages, 3 figures, Accepted Version, PRL, minor wording change

Beyond gentrification: Diversified neighbourhood upgrading in the inner city of Budapest

The concept of gentrification has been extensively used in post-socialist context in association with neighbourhood renewal processes, despite the exact meaning of the term and its social effects not always being sufficiently clarified. This paper builds upon empirical research from downtown Budapest. Our investigation primarily focused on the interplay of three groups of stakeholders involved in urban renewal: politicians, investors and residents. On the basis of our multi-dimensional analysis, we could identify three main types of upgrading: classical gentrification (with two sub-types), as well as incumbent upgrading and soft forms of revitalisation. In the studied neighbourhoods, a mixture of these forms of upgrading could be identified, reflecting a diversified rejuvenation. Gentrification was spatially limited to poverty ridden neighbourhoods subject to local government organised regeneration programmes. The predominance of soft forms of revitalisation is a function of housing market mechanisms as well as the planning control of local districts, which in general together create a healthy social mix despite pervasive regeneration activities

Polyploid superficial cells that maintain the urothelial barrier are produced via incomplete cytokinesis and endoreplication

Summary: The urothelium is an epithelia barrier lined by a luminal layer of binucleated, octoploid, superficial cells. Superficial cells are critical for production and transport of uroplakins, a family of proteins that assemble into a waterproof crystalline plaque that helps protect against infection and toxic substances. Adult urothelium is nearly quiescent, but rapidly regenerates in response to injury. Yet the mechanism by which binucleated, polyploid, superficial cells are produced remains unclear. Here, we show that superficial cells are likely to be derived from a population of binucleated intermediate cells, which are produced from mononucleated intermediate cells via incomplete cytokinesis. We show that binucleated intermediate and superficial cells increase DNA content via endoreplication, passing through S phase without entering mitosis. The urothelium can be permanently damaged by repetitive or chronic injury or disease. Identification of the mechanism by which superficial cells are produced may be important for developing strategies for urothelial repair. : Binucleated superficial cells are critical for urothelial barrier function. Wang et al. show that they derive from binucleated intermediate cells that form via incomplete cytokinesis. Both superficial and intermediate cells increase ploidy via endoreplication, a feature likely to be important for repair and response to environmental changes. Keywords: endoreplication, urothelium, polyploidy, epithelial barrier, regeneratio

Adsorption geometry and electronic structure of iron phthalocyanine on Ag surfaces: A LEED and photoelectron momentum mapping study

We present a comprehensive study of the adsorption behavior of iron phthalocyanine on the low-index crystal faces of silver. By combining measurements of the reciprocal space by means of photoelectron momentum mapping and low energy electron diffraction, the real space adsorption geometries are reconstructed. At monolayer coverage ordered superstructures exist on all studied surfaces containing one molecule in the unit cell in case of Ag(100) and Ag(111), and two molecules per unit cell for Ag(110). The azimuthal tilt angle of the molecules against the high symmetry directions of the substrate is derived from the photoelectron momentum maps. A comparative analysis of the momentum patterns on the substrates with different symmetry indicates that both constituents of the twofold degenerate FePc lowest unoccupied molecular orbital are occupied by charge transfer from the substrate at the interface

Effect of daptomycin and vancomycin on Staphylococcus epidermidis biofilms: An in vitro assessment using fluorescence in situ hybridization

Colonization of in-dwelling catheters by microbial biofilms is a major concern in patient health eventually leading to catheter-related blood stream infections. Biofilms are less susceptible to standard antibiotic therapies that are effective against planktonic bacteria. Standard procedure for the detection of microorganisms on the catheter tip is culture. However, viable but non-culturable cells (VBNCs) may be missed. The aim of this study was to evaluate the use of fluorescence in situ hybridization (FISH) as an indicator to visualize and quantify the effect of the antibiotics daptomycin and vancomycin on biofilms in situ. We established an in vitro catheter biofilm model of Staphylococcus epidermidis biofilms on polyurethane catheters. Biofilm activity was measured by FISH and correlated to colony forming units (CFU) data. Digital image analysis was used for quantification of total biofilm mass and the area of the FISH positive biofilm cells. FISH showed a pronounced effect of both antibiotics on the biofilms, with daptomycin having a significantly stronger effect in terms of both reduction of biofilm mass and number of FISH-positive cells. This supports the anti-biofilm capacity of daptomycin. Interestingly, neither antibiotic was able to eradicate all of the FISH-positive cells. In summary, FISH succeeded in visualization, quantification, and localization of antibiotic activity on biofilms. This technique adds a new tool to the arsenal of test systems for anti-biofilm compounds. FISH is a valuable complementary technique to CFU since it can be highly standardized and provides information on biofilm architecture and quantity and localization of survivor cells

Indigenous Sovereignty: A Reassessment in Light of the UN Declaration on the Rights of Indigenous Peoples

This Article explores the concept of indigenous sovereignty against the backdrop of the resurgence of indigenous peoples as actors in international and domestic law and policy. The Author starts with the traditional Western notion of sovereignty and its dynamization via the principle of self-determination, cabined by the exclusionary concepts of terra nullius and uti possidetis. The next Part delineates the global indigenous renascence occurring since the 1970s and the resulting state practice that has led to treaties and to the development of customary international law in the field. The Article proceeds to analyze the scope and legal effect of the 2007 UN Declaration on the Rights of Indigenous Peoples. It lays out various understandings of indigenous self-government under the rubric of self-determination; and ultimately, based on an assessment of the authentic aspirations of indigenous peoples, their innerworlds, it suggests a functional redefinition of the legal scope and the limits of indigenous sovereignty

Law as a Means to a Public Order of Human Dignity: The Jurisprudence of Michael Reisman

Words cannot do justice to the man who has transformed the lives of so many of us who have gathered at the Yale Law School today. But words are all we have to share our feelings, as we must, over space, and over time. Michael Reisman is the man we have the pleasure and deep satisfaction to honor and to celebrate: our teacher, our guide, our mentor, our friend. He has touched our lives in a variety of ways. In my case, the introduction to his magnificent work was made by a young South African scholar at the Peace Palace in The Hague, and I never looked back. His jurisprudence of insight and empowerment was a liberation indeed-a fountain of truth on how law is really made and changed, and a treasure trove of wisdom on what considerations should guide the decisions we consciously and unconsciously make. He made us, who call themselves professionals of the law, realize that we are not mere bouches de la loi; he challenged us to live up to the role we actually play in society and to assume the responsibility that comes with leadership. This statement of friendship and respect is designed to highlight our honoree\u27s distinct place in the pantheon of jurisprudence (Part I); his keen sense of observation and analysis (Part II); his consummate skills of communication (Part 1II); and his abiding quest for a public order of human dignity (Part IV)