Electronic structure of the muonium center as a shallow donor in ZnO

The electronic structure and the location of muonium centers (Mu) in single-crystalline ZnO were determined for the first time. Two species of Mu centers with extremely small hyperfine parameters have been observed below 40 K. Both Mu centers have an axial-symmetric hyperfine structure along with a [0001] axis, indicating that they are located at the AB_{O,//} and BC_{//} sites. It is inferred from their small ionization energy (~6 meV and 50 meV) and hyperfine parameters (~10^{-4} times the vacuum value) that these centers behave as shallow donors, strongly suggesting that hydrogen is one of the primary origins of n type conductivity in as-grown ZnO.Comment: 4 pages, 4 figures, submitted to PR

A low-rank solution method for Riccati equations with indefinite quadratic terms

Algebraic Riccati equations with indefinite quadratic terms play an important role in applications related to robust controller design. While there are many established approaches to solve these in case of small-scale dense coefficients, there is no approach available to compute solutions in the large-scale sparse setting. In this paper, we develop an iterative method to compute low-rank approximations of stabilizing solutions of large-scale sparse continuous-time algebraic Riccati equations with indefinite quadratic terms. We test the developed approach for dense examples in comparison to other established matrix equation solvers, and investigate the applicability and performance in large-scale sparse examples.Comment: 19 pages, 2 figures, 5 table

Deep polytopic autoencoders for low-dimensional linear parameter-varying approximations and nonlinear feedback design

Polytopic autoencoders provide low-dimensional parametrizations of states in a polytope. For nonlinear PDEs, this is readily applied to low-dimensional linear parameter-varying (LPV) approximations as they have been exploited for efficient nonlinear controller design via series expansions of the solution to the state-dependent Riccati equation. In this work, we develop a polytopic autoencoder for control applications and show how it outperforms standard linear approaches in view of LPV approximations of nonlinear systems and how the particular architecture enables higher order series expansions at little extra computational effort. We illustrate the properties and potentials of this approach to computational nonlinear controller design for large-scale systems with a thorough numerical study.Comment: 9 pages, 6 figures, 2 table

Fertility Ideals of Women and Men Across the Life Course

This paper explores the stability of women’s and men’s fertility preferences across the life course. The data come from the first six waves of the German Family Panel (pairfam), which span the period from 2008/2009 until 2013/2014. In our analysis, fertility preferences are measured using the following question: “Under ideal circumstances, how many children would you like to have?” The average number cited by both women and men is 2.2. With rising age, this number declines modestly. Relying on fixed-effects modelling, we find that neither partnership status nor economic circumstances have any causal effect on fertility preferences. However, as the number of children a respondent has increases, his or her ideal number of children is also likely to grow. Thus, fertility ideals appear to undergo changes over time, and are adjusted in line with the size of the respondent’s own family

Family-Friendly Management, Organizational Performance and Social Legitimacy

Research on family-friendly practices has concentrated on the predictors of their use, particularly from the perspective of either institutional theory or the high involvement or commitment management vogue. This paper first shows how such perspectives can be used to generate hypotheses about the link between family-friendly management and organizational performance. Second, the paper reports research designed to test these, using data from a national representative sample of workplaces across the British economy, the Workplace Employment Relations Survey of 2004 (WERS2004). The results support the high commitment thesis that family-friendly management will strengthen the relationship between commitment and key economic outcomes, as the relationships between workforce commitment and productivity or quality are stronger in organizations when friendly management is high, which is consistent with social exchange theory. Family-friendly management is not, however, related to the human resource outcomes of labour turnover and absenteeism. Nor does the study find support for the argument that its use in conjunction with high involvement management enhances the performance effects of both. Equally, there is no support for the hypothesis from the institutional thesis that family-friendly management has positive effects on the legitimacy of the organization

H3K9me-Independent Gene Silencing in Fission Yeast Heterochromatin by Clr5 and Histone Deacetylases

Nucleosomes in heterochromatic regions bear histone modifications that distinguish them from euchromatic nucleosomes. Among those, histone H3 lysine 9 methylation (H3K9me) and hypoacetylation have been evolutionarily conserved and are found in both multicellular eukaryotes and single-cell model organisms such as fission yeast. In spite of numerous studies, the relative contributions of the various heterochromatic histone marks to the properties of heterochromatin remain largely undefined. Here, we report that silencing of the fission yeast mating-type cassettes, which are located in a well-characterized heterochromatic region, is hardly affected in cells lacking the H3K9 methyltransferase Clr4. We document the existence of a pathway parallel to H3K9me ensuring gene repression in the absence of Clr4 and identify a silencing factor central to this pathway, Clr5. We find that Clr5 controls gene expression at multiple chromosomal locations in addition to affecting the mating-type region. The histone deacetylase Clr6 acts in the same pathway as Clr5, at least for its effects in the mating-type region, and on a subset of other targets, notably a region recently found to be prone to neo-centromere formation. The genomic targets of Clr5 also include Ste11, a master regulator of sexual differentiation. Hence Clr5, like the multi-functional Atf1 transcription factor which also modulates chromatin structure in the mating-type region, controls sexual differentiation and genome integrity at several levels. Globally, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci

Influence of surgical approach on component positioning in primary total hip arthroplasty

Background: Minimal invasive surgery (MIS) has gained growing popularity in total hip arthroplasty (THA) but concerns exist regarding component malpositioning. The aim of the present study was to evaluate femoral and acetabular component positioning in primary cementless THA comparing a lateral to a MIS anterolateral approach. Methods: We evaluated 6 week postoperative radiographs of 52 hips with a minimal invasive anterolateral approach compared to 54 hips with a standard lateral approach. All hips had received the same type of implant for primary cementless unilateral THA and had a healthy hip contralaterally. Results: Hip offset was equally restored comparing both approaches. No influence of the approach was observed with regard to reconstruction of acetabular offset, femoral offset, vertical placement of the center of rotation, stem alignment and leg length discrepancy. However, with the MIS approach, a significantly higher percentage of cups (38.5 %) was malpositioned compared to the standard approach (16.7 %) (p = 0.022). Conclusions: The MIS anterolateral approach allows for comparable reconstruction of stem position, offset and center of rotation compared to the lateral approach. However, surgeons must be aware of a higher risk of cup malpositioning for inclination and anteversion using the MIS anterolateral approach

Misty, Spellbound and the lost Gothic of British girls’ comics.

This article is a case study of the 1970s British girls’ comics Spellbound (DC Thomson, 1976–1977) and Misty (IPC, 1978–1980). These mystery anthology comics followed the more famous American horror comics from publishers like EC Comics - but were aimed at pre-teen girls. The article situates these comics with respect to Gothic critical theory and within the wider landscape of British girls’ comics. Firstly, it closely considers and compares the structure and content of their stories with respect to theories of the terror and horror Gothic. It discovers that both comics offer similar fare, with a subversive streak that undercuts established horror archetypes. The article then looks closely at both titles’ aesthetics and their use of the page to draw comparisons. It uses comics theory and Gothic cinematic theory to demonstrate that the appearance of Misty is more strongly Gothic than the aesthetic of Spellbound. Finally, it considers a selection of stories from both comics and analyses their common themes using Gothic critical theory. It argues that both comics rework Gothic themes into new forms that are relevant to their pre-teen and teenage readers. It concludes by summarising the study’s findings and suggesting that these comics offer a “Gothic for Girls” that is part cautionary tale and part bildungsroman. This article is published as part of a collection on Gothic and horror