Landau Theory of Domain Wall Magnetoelectricity

We calculate the exact analytical solution to the domain wall properties in a multiferroic system with two order parameters that are coupled bi-quadratically. This is then adapted to the case of a magnetoelectric multiferroic material such as BiFeO3, with a view to examine critically whether the domain walls can account for the enhancement of magnetization reported for thin films fo this material, in view of the correlation between increasing magnetization and increasing volume fraction of domain walls as films become thinner. The present analysis can be generalized to describe a class of magnetoelectric devices based upon domain walls rather than bulk properties.Comment: 9 pages, 4 figure

Ground state representations of loop algebras

Let g be a simple Lie algebra, Lg be the loop algebra of g. Fixing a point in S^1 and identifying the real line with the punctured circle, we consider the subalgebra Sg of Lg of rapidly decreasing elements on R. We classify the translation-invariant 2-cocycles on Sg. We show that the ground state representation of Sg is unique for each cocycle. These ground states correspond precisely to the vacuum representations of Lg.Comment: 22 pages, no figur

Influence of phosphoproteins’ biomimetic analogues on remineralization of mineral-depleted resin-dentin interfaces created with ion-releasing resin-based systems

Objectives. The study aimed at evaluating the remineralization of acid-etched dentin pre-treated with primers containing biomimetic analogues and bonded using an ion-releasing Ca-Silicate/CaP light-curable resin-based material.Methods. An experimental etch-and-rinse adhesive system filled with Ca++, PO4-3-relesing micro-fillers was created along with two experimental primers containing biomimetic analogues such as sodium trimetaphosphate (TMP) and/or polyaspartic acid (PLA). Dentin specimens etched with 37% H3PO4 were pre-treated with two aqueous primers containing the polyanionic biomimetic analogues or deionized water and subsequently bonded using the experimental resin-based materials. The specimens were sectioned and analyzed by AFM/nanoindentation to evaluate changes in the modulus of elasticity (Ei) across the resin-dentin interface at different AS storage periods (up to 90 days). Raman cluster analysis was also performed to evaluate the chemical changes along the interface. The phosphate uptake by the acid-etched dentin was evaluated using the ATR-FTIR. Additional resin–dentin specimens were tested for microtensile bond strength. SEM examination was performed after de-bonding, while confocal laser microscopy was used to evaluate the interfaces ultramorphology and micropermeability.Results. Both biomimetic primers induced phosphate uptake by acid-etched dentin. Specimens created with the ion-releasing resin in combination with the pre-treatment primers containing either PLA and TMA showed the greatest recovery of the Ei of the hybrid layer, with no decrease in μTBS (P>0.05) after 3-month AS storage. The ion-releasing resin applied after use of the biomimetic primers showed the greatest reduction in micropermeability due to mineral precipitation; these results were confirmed using SEM.Significance. The use of Ca-Silicate/CaP ion-releasing resin-based system applied to acid-etched dentin pre-treated with biomimetic primers containing analogues of phosphoproteins such as poly-L-aspartic acid and/or sodium trimetaphosphate, provide a suitable bonding approach for biomimetic remineralization of resin-dentin interfaces.This work was supported by grant MINECO/FEDER MAT2011-24551 and MINECO/FEDER MAT2014-52036-P

Microtensile bond strength of several adhesive systems to different dentin depths

Abstract no. 15published_or_final_versio

Surface treatments for improving bond strength to prefabricated fiber posts: A literature review

This literature review summarizes the research on fiber post surface treatments and provides information related to their benefit in enhancing bond strength to composites, based on the results of original scientific full papers from peer-reviewed journals listed in Pub Med. The search was conducted using the terms "fiber post," "surface treatment" "surface conditioning," "etching" and "sandblasting." A consistent number of in vitro studies that investigated the surface treatment of fiber posts in an attempt to improve bond strength have been published to date. Their results have been summarized in the following categories: chemical treatments and micromechanical treatments of fiber post surfaces (or a combination of both principles). The majority of available literature data is based on studies that investigated different "chairside" post superficial treatments. According to the in vitro results, surface conditioning improves fiber post bonding properties, and the bond strength of pre-treated fiber posts to restorative materials is satisfactory. Long-term clinical studies are needed prior to making a general recommendation for their use

Small-area methods for investigation of environment and health

Small-area studies offer a powerful epidemiological approach to study disease patterns at the population level and assess health risks posed by environmental pollutants. They involve a public health investigation on a geographic scale (e.g. neighbourhood) with overlay of health, environmental, demographic and potential confounder data. Recent methodological advances, including Bayesian approaches, combined with fast growing computational capabilities permit more informative analyses than previously possible, including the incorporation of data at different scales, from satellites to individual-level survey information. Better data availability has widened the scope and utility of small-area studies, but also led to greater complexity, including choice of optimal study area size and extent, duration of study periods, range of covariates and confounders to be considered, and dealing with uncertainty. The availability of data from large, well-phenotyped cohorts such as UK Biobank enables the use of mixed-level study designs and the triangulation of evidence on environmental risks from small-area and individual-level studies, therefore improving causal inference, including use of linked biomarker and -omics data. As a result, there are now improved opportunities to investigate the impacts of environmental risk factors on human health, particularly for the surveillance and prevention of non-communicable diseases

The Current Status of the Distribution Range of the Western Pine Beetle, Dendroctonus brevicomis (Curculionidae: Scolytinae) in Northern Mexico

Abstract The distribution range of the western pine beetle Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae) is supported only by scattered records in the northern parts of Mexico, suggesting that its populations may be marginal and rare in this region. In this study, we review the geographical distribution of D. brevicomis in northern Mexico and perform a geometric morphometric analysis of seminal rod shape to evaluate its reliability for identifying this species with respect to other members of the Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae) complex. Our results provide 30 new records, with 26 distributed in the Sierra Madre Occidental and 4 in the Sierra Madre Oriental. These records extend the known distribution range of D. brevicomis to Durango and Tamaulipas states in northern Mexico. Furthermore, we find high geographic variation in size and shape of the seminal rod, with conspicous differences among individuals from different geographical regions, namely west and east of the Great Basin and between mountain systems in Mexico. Key words: seminal rod shape, geometric morphometry, Dendroctonus frontalis comple

‘If you look the part you’ll get the job’: should career professionals help clients to enhance their career image?

This article presents a critical exploration of the role of career professionals in supporting people to reflect on and enhance their appearance, attractiveness and self-presentation (career image). The article is conceptual and based on a review of the broader literature on career success, appearance and attractiveness. It explores the evidence for a relationship between attractiveness and career, and the authors propose a conceptual framework in which career image is comprised of three elements (interpersonal skills, aesthetic presentation and beauty). The paper examines a possible role for career professionals in relation to this and then critically examines this role and concludes with the proposition of a research agenda in this area