Signed Roman domination in graphs

In this paper we continue the study of Roman dominating functions in graphs. A signed Roman dominating function (SRDF) on a graph G=(V,E) is a function f:V→{?1,1,2} satisfying the conditions that (i) the sum of its function values over any closed neighborhood is at least one and (ii) for every vertex u for which f(u)=?1 is adjacent to at least one vertex v for which f(v)=2. The weight of a SRDF is the sum of its function values over all vertices. The signed Roman domination number of G is the minimum weight of a SRDF in G. We present various lower and upper bounds on the signed Roman domination number of a graph. Let G be a graph of order n and size m with no isolated vertex. We show that $\gamma _{\mathrm{sR}}(G) \ge\frac{3}{\sqrt{2}} \sqrt{n} - n$ and that γ _sR(G)≥(3n?4m)/2. In both cases, we characterize the graphs achieving equality in these bounds. If G is a bipartite graph of order n, then we show that $\gamma_{\mathrm{sR}}(G) \ge3\sqrt{n+1} - n - 3$ , and we characterize the extremal graphs.     

Contingent capital makes credit crunches less likely: but do banks want to have it?

We analyze whether the use of CoCo bonds as a financing instrument improves credit supply and therefore reduces the likelihood of a credit crunch. In our simple model, banks decide about granting an additional loan. In case of the bank violating the regulatory constraint, it needs to issue equity associated with adjustment costs. The contribution of the paper is threefold: First, this simple model explains credit crunches in the sense that the loan decision does not only depend on loan characteristics but also on the bank’s prospects. Second, CoCo bonds can always be designed such that all loans with non-negative net present value are granted, which prevents the danger of a credit crunch. Third, banks might not want to issue CoCo bonds even though these instruments help to improve credit supply. This problem primarily concerns banks with favorable prospects, thereby challenging the notion that CoCo bonds should be issued in good times as a protection during bad times.     

Roles,race and subjective well-being: A longitudinal analysis of elderly men

The basic contention of this paper is that research on subjective well-being would benefit from an integration of theory and research from other studies of subjective states, such as mental and physical health. Toward that end, we present results of an analysis of the impact of race and social roles on subjective well-being in a nationally representative sample of elderly men. The findings demonstrate that particular role configurations have an effect on happiness and that these effects are different for blacks and whites. Theoretical implications of these findings for subjective well-being research and role accumulation theory are discussed.     

Forced Coexistence and Economic Development: Evidence From Native American Reservations

Studying Native American reservations, and their historical formation, I find that their forced integration of autonomous polities into a system of shared governance had large negative long‐run consequences, even though the affected people were ethnically and linguistically homogenous. Reservations that combined multiple sub‐tribal bands when they were formed are 30% poorer today, even when conditioning on pre‐reservation political traditions. The results hold with tribe fixed effects, identifying only off within‐tribe variation across reservations. I also provide estimates from an instrumental variable strategy based on historical mining rushes that led to exogenously more centralized reservations. Data on the timing of economic divergence and on contemporary political conflict suggest that the primary mechanism runs from persistent social divisions through the quality of local governance to the local economic environment.     

Parent Management Training, Relationships with Agency Staff, and Child Mental Health: Urban Foster Parents' Perspectives

Many foster parents are ill prepared to meet the behavioral needs of children placed in their homes. Research suggests they lack training in evidence-based behavioral interventions and feel unsupported by child welfare professionals. Given the complex needs of foster children and increased rates of placement disruption for foster children with behavior problems, implementation of effective interventions is essential. However, little is known about foster parents' receptivity to these types of interventions. In this qualitative study, we examine urban foster parents' perceptions of the specific elements of parent management training (PMT), an evidence-based treatment for disruptive behaviors that teaches parents to improve desired behaviors and decrease oppositional behaviors by rewarding positive behaviors (positive reinforcement) and responding to negative behaviors with mild, consistent punishments such as timeout or a privilege removal. We present data from four focus groups (N = 38). While the questions focused on parent's perceptions of PMT, responses often related to parent interactions with agency staff. Four strong themes emerged from the data. First, foster parents discussed a need for more support and training in how to address children's behaviors, but also had concerns that some PMT discipline techniques would be ineffective based on their past experiences with foster children. Second, they described how staff communication skills and allegations of child abuse could affect parents' motivation to continue fostering. Third, they expressed a need for more detailed information about children's histories and visits with biological families as the lack of information contributed to difficulty in meeting foster children's needs. They suggested that joint training of foster parents and staff in the intervention could improve their ability to work together to support the child's positive behaviors. Finally, parents reported little involvement in child mental health services and doubted the effectiveness of the mental health services their foster children received.     

Handicaps in Job Assignment: Insiders,Outsiders and Gender

In this study, I use personnel data from a large German company in order to analyze handicaps in job assignment. First, I compare the productivity-relevant characteristics (university degree and work experience) and wages between insiders and outsiders as well as between men and women, who have been assigned to jobs at the same hierarchical level. Second, I estimate promotion probabilities and duration models for the time until the next promotion. The overall findings indicate a significant handicap in job assignment for outsiders with respect to schooling and little evidence that women are handicapped. While gender differences in wages within job levels and promotion probabilities are small, women have, on average, significantly less work experience than men at the same job level.     

Who speaks up to whom? A relational approach to employee voice

We adopt a relational approach to examine the effects of social relations and formal structure on who speaks up to whom about problems at work. Data were collected in a two-wave employee survey in three Dutch preschools. Using exponential random graph modeling, we found significant positive effects of formal structure (recipient's hierarchical level; team co-membership) and good relations between speaker and recipient on the likelihood of voice in a dyad. Speaker's hierarchical level had positive effects, significant in Wave 1. Speaker's degree centrality significantly reduced the likelihood of voice, whereas recipient's degree centrality had no effect.     

A Note on “Sourcing Decisions with Stochastic Supplier Reliability and Stochastic Demand”

This note complements the study of Burke, Carillo, and Vakharia ( 2009 hereafter “BCV”) which analyzes a class of single‐product multisourcing problems under stochastic demand and random yields. The purpose is twofold. First, we prove that the objective function used by these authors is only a lower bound for the expected profit for which we provide the correct expression. Second, we show on some of the numerical instances provided in BCV's study that the structure and the performance of the BCV ordering policy may be substantially different from the optimal ordering policy. We conclude by giving general qualitative insights characterizing suboptimality of the BCV solution.     

Entrepreneurial Marketing in Online-Netzwerken

A growing number of professionals use online social networks (e.g., Xing or LinkedIn) for business reasons by specifically promoting themselves. Especially executives and entrepreneurs use business social networks as a marketing tool in order to manage their business contacts and, thus, positioning themselves as a brand. Using on Keller’s (1993) customer-based brand equity model, we focus on the special behavior of entrepreneurs in such social networks. Based on the a large data set from a leading social network, we empirically analyze whether entrepreneurs act differently than other users and whether this strategy pays off. Based on a SUR model, we determine what the drivers for entrepreneurs’ profile views and contacts are. The results show that entrepreneurs focus on communicating their intentions and competencies and engage actively in the community. Especially participating in user groups and attending community events are key drivers for success.     

Creeping-In als neues Instrument des Erwerbs von Unternehmenskontrollrechten ?C Taktische Meisterleistung oder unkalkulierbares Risiko?

A modern method for (partial) acquisitions is the so called creeping-in tactic. In this procedure the acquirer uses cash settled equity swaps to undermine WpHG notification requirements systematically until she holds at least 30% of the voting rights in the target company. In this case the acquirer has the obligation to submit a mandatory takeover bid for the remaining outstanding shares. In many cases acquirers are not interested in a complete acquisition of the target company but rather want to make use of low shareholder presence levels during the general assembly and therefore have the opportunity to significantly influence fundamental decisions like, e.g. allocation of the net income, corporate actions etc. The mandatory takeover bid has to be equal at least to the three months average share price. At first glance, this involves a high risk of an unintentional acceptance by the targets?? shareholders. The goal of this paper is to analyze the effectiveness of the mandatory takeover bid. We show that with a temporal shift of the mandatory takeover bid to a point in time when the share price is above the three months average share price an unintentional acceptance is virtually impossible. In a logit-regression company specific context factors for the acceptance risk are indentified and rejected.