A tighter insertion-based approximation of the crossing number

Let G be a planar graph and F a set of additional edges not yet in G. The multiple edge insertion problem (MEI) asks for a drawing of \(G+F\) with the minimum number of pairwise edge crossings, such that the subdrawing of G is plane. Finding an exact solution to MEI is NP-hard for general F. We present the first polynomial time algorithm for MEI that achieves an additive approximation guarantee—depending only on the size of F and the maximum degree of G, in the case of connected G. Our algorithm seems to be the first directly implementable one in that realm, too, next to the single edge insertion. It is also known that an (even approximate) solution to the MEI problem would approximate the crossing number of the F-almost-planar graph \(G+F\), while computing the crossing number of \(G+F\) exactly is NP-hard already when \(|F|=1\). Hence our algorithm induces new, improved approximation bounds for the crossing number problem of F-almost-planar graphs, achieving constant-factor approximation for the large class of such graphs of bounded degrees and bounded size of F.     

Capital structure decisions in family firms: empirical evidence from a bank-based economy

This paper analyzes the question if and how founding families influence the capital structure decision of their firms. By using a unique, partially hand-collected panel dataset of 660 listed German companies (5,135 firm years) over the period 1995–2006, we come up with the following results: German family firms have significantly lower leverage ratios than non-family firms. With respect to the question how families influence the capital structure of their firms, we can show that the family impact is mostly driven via management involvement. In this context, we also detect that the presence of a founder CEO has a strong negative effect on the leverage ratio. Our results prove to be stable against a battery of robustness tests, including the influence of other types of blockholders and the firms’ life cycle. Moreover, we use a propensity-score based matching estimator to alleviate concerns of reverse causality. Overall, our study suggests a strong, negative and causal relationship between family firm characteristics (especially family management) and the level of leverage.     

The Impact of Complexity on Knowledge Transfer in Manufacturing Networks

Coordinating knowledge transfer within multi‐plant manufacturing networks is a challenging task. Using a computational model, we examine when it is beneficial to create production knowledge within a central unit, the “lead factory,” and transfer it to geographically dispersed plants. We demonstrate that the knowledge transfer generates a trade‐off between a positive cost‐saving effect due to fewer adaptations in each plant, and a negative transfer cost effect due to the costly knowledge transfer itself. The complexity of the production process moderates the performance implications of the knowledge transfer because it determines the relative strength of these two effects. For production processes with low complexity, knowledge transfer can engender superior network performance. Here, an optimal extent of knowledge transfer exists, and thus, a complete knowledge transfer is not performance maximizing. For production processes with medium and high levels of complexity, performance is reduced rather than enhanced through knowledge transfer so that it is optimal not to transfer any knowledge from the lead factory to the plants. While we analyze knowledge transfer within a manufacturing network, our results are transferable to other settings that consist of a knowledge sending and receiving unit.     

Psychiatric Symptoms and Same-Sex Sexual Attraction and Behavior in Light of Childhood Gender Atypical Behavior and Parental Relationships

This study explores the relation between the level of current symptoms of depression and anxiety and recalled childhood gender atypical behavior (GAB), and quality of relationships with parents among men and women who reported same-sex sexual attraction or engaged in same-sex sexual behavior and men and women who did not. Matched pairs, 79 men (n = 158) and 148 women (n = 296), with equal levels of GAB were created of Finnish participants with either same-sex sexual attraction or behavior and participants without. The measures used were retrospective questionnaires. Ratings of maternal and paternal over-control and coldness differed as a function of same-sex sexual attraction or behavior. Childhood GAB was correlated with negative ratings of parental relationships. Both same-sex sexual attraction or behavior and a history of childhood GAB affected the reported levels of current depression and anxiety. Only gender typical participants with no same-sex sexual attraction or behavior reported significantly lower levels of symptoms. The findings suggest that childhood GAB is related to later distress both among hetero- and homosexual individuals. The elevated level of psychological distress among homosexual individuals, reported in several studies, might—to some extent—be caused by their generally higher levels of childhood GAB as opposed to a homosexual orientation per se.     

Overcoming neoliberal globalization: social-ecological transformation from a Polanyian perspective and beyond

ABSTRACT

The ecological crisis has intensified in many respects. Prominent proposals to deal with the crisis are discussed under the header ‘sustainability transformations’ or even ‘Great Transformation’. We argue that most contributions suffer from a narrow analytical approach to transformation ignoring the largely unsustainable dynamics of global capitalism and the power relations involved in it. Thus, a ‘new critical orthodoxy’ of knowledge about transformation is emerging which runs the danger to contribute to a spatially and socially highly uneven green capitalism. This article claims that the current debate on social-ecological transformation can be enriched by a Polanyian understanding but also based on regulation theory. We distinguish between three types of transformation: incremental adaptation of the current institutional systems, institutional change in favour of a new ‘green’ phase of capitalism, and a post-capitalist great transformation that implies a profound structural change of the mode of production and living.     

Rain and the Democratic Window of Opportunity

We show that democratic change may be triggered by transitory economic shocks. Our approach uses within‐country variation in rainfall as a source of transitory shocks to sub‐Saharan African economies. We find that negative rainfall shocks are followed by significant improvement in democratic institutions. This result is consistent with the economic approach to political transitions, where transitory negative shocks can open a window of opportunity for democratic improvement. Instrumental variables estimates indicate that following a transitory negative income shock of 1 percent, democracy scores improve by 0.9 percentage points and the probability of a democratic transition increases by 1.3 percentage points.     

Determinants of sexual arousal and the accuracy of its self‐estimation in sexually functional males

Men with and without sexual dysfunction present with varying patterns of agreement between subjective estimates of sexual arousal and more objective psychophysiological measures of the same construct. This relative accuracy seems to be associated with sexual function, with men who have sexual dysfunction presenting less accurate estimations (mostly reporting below measured arousal levels). The purpose of this study is to clarify the processes underlying sexual arousal and the accuracy of its self‐estimation. We looked at potential predictors of sexual arousal (subjective and physiological) and accuracy in estimating objective sexual arousal in a sample of 60 sexually functional males. Predictors included pre‐existing sexual attitudes (erotophobia), both trait and state positive and negative affect, self‐focused attention, and interoceptive awareness. Results indicate that this sexually functional sample generally reported below their own erection level. Interestingly, trait negative affect was associated with somewhat lower levels of subjective arousal and higher levels of physiological arousal. On the other hand, state positive affect facilitated both subjective and objective arousal and increased somewhat the accuracy of estimates of erectile responding. Pre‐existing sexual attitudes as well as variations in self‐focused attention and interoceptive awareness evidenced little effect on sexual arousal or the accuracy of its estimation.     

Hat die personzentrierte, gruppenbezogene Beratung einen Platz in der Zahnmedizin?

Group-counseling in dentistry represents an unusual subject, even though consultation and advisory services are integral parts in the daily dental practice. These are, however, almost exclusively individual consultations of patients who are only occasionally accompanied by a spouse or a parent. Moreover, such advice is almost always regarded as medical advice provided by an expert. In dentistry, and particularly in the field of chronic orofacial pains, psychological and social factors play a significant role alongside somatic problems. On the basis of the literature and my personal experience that a person-centered approach is well accepted by patients, this essay will describe why the person-centered approach in general and a person-centered group-counseling in particular represent promising alternatives for successful counseling and therapy for this clientele. Additionally, I will adress problems with the implementation in the daily routine of a dental practice and the need for scientific verification of that approach.