Subset sum problems with digraph constraints

We introduce and study optimization problems which are related to the well-known Subset Sum problem. In each new problem, a node-weighted digraph is given and one has to select a subset of vertices whose total weight does not exceed a given budget. Some additional constraints called digraph constraints and maximality need to be satisfied. The digraph constraint imposes that a node must belong to the solution if at least one of its predecessors is in the solution. An alternative of this constraint says that a node must belong to the solution if all its predecessors are in the solution. The maximality constraint ensures that no superset of a feasible solution is also feasible. The combination of these constraints provides four problems. We study their complexity and present some approximation results according to the type of input digraph, such as directed acyclic graphs and oriented trees.     

International coopetition for innovation: Are the benefits worth the challenges?

International coopetition has rarely been studied in relation to innovation. Further exploration of effects of international coopetition, i.e. the pursuit of simultaneous cooperation and competition, on a firm’s innovation performance is especially important as such a relationship is challenging with a high propensity to fail. This observation formed the point of departure for this study, which aims to increase the understanding of the effects of international coopetition on firm innovativeness and how these effects are conditioned on the magnitude of the organizational adjustments a firm introduces. We use an unbalanced panel of 9839 firms that participated in four waves of the Swedish Community Innovation Survey between 2008 and 2014 as our empirical base. We illustrate that firms that cooperate with competitors internationally are more likely to exhibit higher propensity to introduce radical innovations, yet this effect is conditioned upon the magnitude of organizational adjustments. Overall, our study contributes to the understanding of the implications of international coopetition and what a firm needs to benefit from it.     

Probabilistic population projections for countries with generalized HIV/AIDS epidemics

In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-term projections of policy-relevant quantities for the epidemic. We propose a simpler approach that is more compatible with existing UN projection methods for other countries. Changes in life expectancy are projected probabilistically using a simple time series regression and then converted to age- and sex-specific mortality rates using model life tables designed for countries with HIV/AIDS epidemics. These are then input to the cohort component method, as for other countries. The method performed well in an out-of-sample cross-validation experiment. It gives similar short-run projections to Spectrum/EPP, while being simpler and avoiding multistate modelling.     

Contract design and insurance fraud: an experimental investigation

This paper experimentally examines the impact of contract design on insurance fraud. We test how fraud behavior varies for insurance contracts with full coverage, a straight deductible or claim-dependent premiums (bonus-malus contracts), in a setup where rational and selfish individuals have an incentive to always claim the maximum possible indemnity. We find a substantial impact of contractual arrangements: Deductible contracts lead to a greater extent to claim build-up than full coverage contracts. In contrast, bonus-malus contracts that entail the same net gains from fraud as deductible contracts do not increase claim build-up. Thus, our results indicate that bonus-malus contracts may be superior to deductible contracts for behavioral reasons.     

Advancing Social Capital Measurement: Using General Social Survey Cycles to Develop an Efficient Survey Instrument

The General Social Survey (GSS) has provided significant insight about the state of societies around the world through the International Social Survey Programme (ISSP). Although broadly applicable, in this study the context for developing a new social capital survey instrument covers the Canadian GSS since 1985. Questions in the GSS are often used by researchers who are interested in specific questions or themes for use in some form of re-sampling. Given significant social and relational themes, GSS cycles from 1985 to 2013 were reviewed using a social capital framework to produce a new Social Capital GSS survey instrument. A process of vetting and sorting questions led to development of a 41 question instrument that includes 16 demographic and context variables and 25 social network and trust variables. After testing and refinement, the instrument was used with a randomly sampled group across selected East Hamilton Census Tracts that are differentiated by median income and a standard deviation above and below respectively (n?=?97).     

Effects of a Mindfulness Task on Women’s Sexual Response

Mindfulness-based interventions are effective at improving symptoms of sexual dysfunction in women. The mechanisms by which mindfulness improves sexual function are less clear. The main objective of our study was to investigate the impact of a mindfulness task on sexual response in women. Forty-one women (mean age = 27.2, SD = 5.6) participated in two laboratory sessions that each included two erotic films and one attention task that were presented in counterbalanced order. Both attention tasks consisted of a six-minute audio recording of either a modified body scan, focusing on genital arousal sensations (mindfulness condition), or a visualization exercise. Subjective and genital sexual arousal were measured continuously during stimulus presentation. The mindfulness task led to greater subjective and lower genital arousal. The agreement of subjective and genital sexual arousal (i.e., concordance) was greater in the mindfulness condition. Trait mindfulness was related to lower sexual arousal but also greater sexual concordance in women. Mindfulness-based interventions that encourage women to focus on physical arousal sensations in the here and now may be associated with women’s improved sexual function by enhancing feelings of sexual arousal during sexual activity and by increasing concordance between subjective and genital sexual arousal.     

Legal Marriage,Unequal Recognition,and Mental Health Among Same‐Sex Couples

The authors examined whether the perception of unequal relationship recognition ‐ a novel couple‐level minority stressor ‐ has negative consequences for mental health among same‐sex couples. Data were analyzed from a dyadic study of 100 same‐sex couples (200 individuals) in the United States. Being in a legal marriage was associated with lower perceived unequal recognition and better mental health; being in a registered domestic partnership or civil union—but not also legally married—was associated with greater perceived unequal recognition and worse mental health. Actor partner interdependence models tested associations between legal relationship status, unequal relationship recognition, and mental health (nonspecific psychological distress, depressive symptomatology, and problematic drinking), net controls (age, gender, race and ethnicity, education, and income). Unequal recognition was consistently associated with worse mental health, independent of legal relationship status. Legal changes affecting relationship recognition should not be seen as simple remedies for addressing the mental health effects of institutionalized discrimination.     

Die Finanzialisierung von Unternehmen

Since the 1990s the financialization of the enterprise is an increasingly important aspect of capitalist development also in Germany. However, more recently a growing number of scholars point at a problematic conceptual stretching of financialization. The term has been defined too differently and ambiguously and has not been distinguished sufficiently from seemingly similar concepts. Financialization has been prematurely identified with a set of fixed effects often condensed to stagist concepts of capitalist development. When analyzing effects financialization has been regarded in isolation without considering interaction effects with other structurations of fields and hence the multi-referentiality of the enterprise. In order to overcome these shortcomings the article proposes a concept for the analysis of firm level financialization which draws on a more general sociological concept of field structuration and dynamics in which the “multi-referential enterprise” operates. Based on this concept the article analyses episodes of financialization in Germany showing its dynamics and limits. Financialization of enterprises proves to be structurally limited, institutionally contested, and unfolds its effects in deferent actor constellations at firm level due to its multiple and contradictory embeddedness.