Experimental design for response surface gradient estimation

In this paper, a new experimental design and gradient estimation procedure is presented for Phase I response surface optimization. The design is motivated by basic principles of differential calculus, which imply that if a point in Rⁿ has been reached by exactly minimizing a function along a given direction, then the gradient of the function at that point must be orthogonal to the search direction followed. While exact line search is not required for the new design to be effective, this principle implies that the dimension of the gradient estimation procedure may often be reduced from n to n-1 variables, and the experimenter is able to concentrate experimental effort within the most productive region around the center of the design. The new design and gradient estimation procedures are presented, and bias and variance properties are derived. The effectiveness of the new design is shown to depend on the experimenter's ability to terminate line search within a near-stationary region of the line search function A simple heuristic is presented which indicates whether the new design should be used at a given experimental region.     

Slope heuristics: overview and implementation

Model selection is a general paradigm which includes many statistical problems. One of the most fruitful and popular approaches to carry it out is the minimization of a penalized criterion. Birgé and Massart (Probab. Theory Relat. Fields 138:33–73, 2006) have proposed a promising data-driven method to calibrate such criteria whose penalties are known up to a multiplicative factor: the “slope heuristics”. Theoretical works validate this heuristic method in some situations and several papers report a promising practical behavior in various frameworks. The purpose of this work is twofold. First, an introduction to the slope heuristics and an overview of the theoretical and practical results about it are presented. Second, we focus on the practical difficulties occurring for applying the slope heuristics. A new practical approach is carried out and compared to the standard dimension jump method. All the practical solutions discussed in this paper in different frameworks are implemented and brought together in a Matlab graphical user interface called capushe. Supplemental Materials containing further information and an additional application, the capushe package and the datasets presented in this paper, are available on the journal Web site.     

Tipping the Multiracial Color-Line: Racialized Preferences of Multiracial Online Daters

Building on previous work on US multiraciality, we analyze the messaging patterns of Asian-white, Hispanic-white, and black-white multiracial heterosexual     

More present than absent: Men who use domestic violence and their fathering

An earlier article referred to the “absent presence” of the perpetrator in the lives of children and their mothers who have lived with domestic violence. It identified the ways in which the shadow of the perpetrator continued and was evidenced in the “symptoms of abuse” that both women and children experienced in spite of his absence. The current article argues that fathers who use violence are actually more present than absent in the lives of children (and women), even following separation. A mixed method approach surveyed men in Men's Behaviour Change Programs (N = 101), and interviewed women who had experienced violence (N = 50). The studies reported that the majority of men in both the quantitative men's study (80%) and the qualitative women's study (77%) had substantial contact with children. The women's interviews highlight the problematic fathering that many of their children experienced, both before and after separation. They reported very high levels of child abuse and poor attitudes to both women and children. The article concludes that the family violence and child welfare systems are poorly configured to address fathers who use violence and continue to hold substantial parenting roles, including following separation.     

Retaining clients in an outcome monitoring evaluation study: HIV prevention efforts in community settings

The Centers for Disease Control and Prevention (CDC), Division of HIV/AIDS Prevention (DHAP) conducted outcome monitoring studies on evidence-based interventions (EBIs) provided by CDC-funded community-based organizations (CBOs). Critical to the success of outcome monitoring was the ability of CBOs to recruit and retain clients in evaluation studies. Two EBIs, Video Opportunities for Innovative Condom Education and Safer Sex (VOICES/VOCES) and Healthy Relationships, were evaluated using repeated measure studies, which require robust follow-up retention rates to increase the validity and usefulness of the findings. The retention rates were high for both VOICES/VOCES CBOs (95.8% at 30 days and 91.1% at 120 days), and Healthy Relationships CBOs (89.5% at 90 days and 83.5% at 180 days). This paper presents an overview of the retention of clients, challenges to follow-up, and strategies developed by CBOs to achieve high retention rates. These strategies and rates are discussed within the context of the CBOs’ target populations and communities.     

Research Review: Engaging men: a multi‐level model to support father engagement

While there is a growing body of work on using fatherhood as an opportunity to engage men in strategies to prevent child maltreatment and further acts of domestic violence, there is limited research on engaging fathers in strategies to prevent domestic violence from occurring. To fill this gap in the literature, this paper explores existing father engagement frameworks used in child and family services and supports a multi‐level model of father engagement for domestic violence primary prevention. Drawing together evidence about father engagement from a range of studies, including the more general parenting literature, we describe factors that influence father engagement based on an analysis of the literature. These factors include accessibility, staff attitudes and behaviours, programme marketing and the format of service provision.     

Absent presence: the ongoing impact of men's violence on the mother–child relationship

This paper draws from interviews with 45 mothers and 52 children who participated in an action research project to develop activities to support women and children in the aftermath of domestic violence. A thematic analysis was used to analyse the data and explore the question: In what ways does the perpetrator of abuse remain present in the lives of women and children following separation? The paper invites workers to recognize the distortions created by domestic violence that may need to be identified and addressed in the aftermath of violence. The ways in which past trauma, erosion of self‐esteem and the undermining of the mother–child relationship continues to create a shadow across the present relationship are identified. The continued presence of the perpetrator of abuse through child contact arrangements and ongoing harassment is also highlighted. The ‘absent presence’ of the abusive partner is posited as a concept to assist workers with a framework through which to understand problems in the mother–child relationship which emerge when living with and separating from a violent partner. The paper has implications for social workers orientating practice to focus on perpetrator accountability and support strengthening the mother–child relationship.     

Creating stabilizers and safety nets for successor executives' high‐wire act

This article explores executive succession planning in a nonprofit health care organization with a strong values‐based culture. Case study research was used to explore how retiring executives have prepared the organization for their departure and have used various strategies in an attempt to limit any potentially negative impact.