Efficient computation of location depth contours by methods of computational geometry

The concept of location depth was introduced as a way to extend the univariate notion of ranking to a bivariate configuration of data points. It has been used successfully for robust estimation, hypothesis testing, and graphical display. The depth contours form a collection of nested polygons, and the center of the deepest contour is called the Tukey median. The only available implemented algorithms for the depth contours and the Tukey median are slow, which limits their usefulness. In this paper we describe an optimal algorithm which computes all bivariate depth contours in O(n ²) time and space, using topological sweep of the dual arrangement of lines. Once these contours are known, the location depth of any point can be computed in O(log² n) time with no additional preprocessing or in O(log n) time after O(n ²) preprocessing. We provide fast implementations of these algorithms to allow their use in everyday statistical practice.     

Affection and conflict in marital and parent-child relationships

In this study, we examined affection and conflict in marital and parent-child relationships, as reported by mothers, fathers, and 9- and 10-year-old children in a community sample of 87 families. Affection and conflict were inversely related within relationships, with mixed findings across relationships. Most reports showed an association between marital and parent-child conflict as well as between marital and parent-child affection. According to fathers, however, the association between marital affection and father-child affection is moderated by marital conflict. Clinical implications of the associations between positive and negative dimensions of family interaction and of the links between marital and parent-child relations are discussed.     

Are game theoretic concepts suitable negotiation support tools? From Nash equilibrium refinements toward a cognitive concept of rationality

If game theory is to be used as a negotiation support tool, it should be able to provide unambiguous recommendations for a target to aim at and for actions to reach this target. This need cannot be satisfied with the Nash equilibrium concept, based on the standard instrumental concept of rationality. These equilibria, as is well known, are generally multiple in a game. The concept of substantive or instrumental rationality has proved to be so pregnant, however, that researchers, instead of re-evaluating its use in game theory, have simply tried to design concepts related to the Nash equilibrium, but with the property of being unique in a game — i.e., they have devised ways ofselecting among Nash equilibria. These concepts have been labeledrefined Nash equilibria. The purpose of this paper is to show the following.

1. The different types of refined Nash equilibria, based on the principle of backward induction, can lead to severe contradictions within the framework itself. This makes these concepts utterly unsatisfactory and calls for a new appraisal of the reasoning process of the players.
2. The degree of confidence in the principle of backward induction depends upon the evaluation of potential deviations with respect to the extended Nash equilibrium concept used and upon the possible interpretations of such deviations by the different players. Our goal is to show that the nature of these possible interpretations reinforces the argument that a serious conceptual reappraisal is necessary.
3. Some form of forward induction should then become the real yardstick of rationality, extending Simonianprocedural rationality towards the concept ofcognitive rationality. This could open the way to a renewed game theoretic approach to negotiation support systems. Such a research program, which would be a revision of the basic game theoretic concepts, is dealt with in the end of the paper.

     

The Norwegian state railways—Profit-motivated enterprise or a community service?

In Norway there is increasing realization among politicians and the general public that it will be to the advantage of the community to make better use of the transport facilities offered by the railways. There is extensive agreement, across party lines, that the railways should not be operated on purely business principles and that railway policy must be formulated to contribute to the overall aims of social policy.However, general views and political claims of this kind are far removed from the problems encountered in putting theory into practice. Where is the boundary line between the proper extent of railway facilities to be provided for the community and the facilities to be provided by other forms of transport?Assuming that we were able to draw such a line, what measures would we have to take in our endeavour to approach the proper economic balance of transport work between the railways and other forms of transport?The political parties are sharply divided in their views as to what measures are acceptable. Controversial measures include economic sanctions or support and regulatory legislation. There is no reason to suppose that these problems are peculiar to Norway. They are no doubt shared by many other countries.     

Effects of the physical accessibility of maternal health services on their use in rural Haiti

An analysis of data from the 2000 Demographic and Health Survey shows that little use is made of antenatal and delivery-care services in rural Haiti. After adjusting for individual-level factors, poor road conditions significantly reduce the likelihood of timely receipt of antenatal care and of four or more antenatal care visits, while the availability of a health centre within 5 kilometres significantly increases the odds of each outcome. The odds of being attended at delivery by trained medical personnel and of institutional delivery are significantly reduced by mountainous terrain and distance from the nearest hospital, and are increased if a health worker providing antenatal care is present in the neighbourhood. Neighbourhood poverty reduces the likelihood of safe delivery care. The findings suggest that improving the use made of maternal healthcare services would require, among other things, improvement of the availability of services and road conditions, and the reduction of poverty.     

Body image,satisfaction with sexual life,self-esteem,and anxiodepressive symptoms: A comparative study between premenopausal,perimenopausal, and postmenopausal women

Menopause is an important life transition in women, and it is associated with significant physical and psychological changes. This study aimed at examining how the menopausal transition influences body image and satisfaction with sexual life. To this aim, body image dissatisfaction, sexual dissatisfaction, and self-esteem were compared in three groups of women with distinct menopausal status (premenopausal n = 142, perimenopausal n = 66, or postmenopausal n = 149), while controlling for depressive and anxiety symptoms and BMI. Using ANOVA between these three groups, we observed that dissatisfaction with body image was significantly higher in the perimenopausal sample compared with its premenopausal counterpart. In the postmenopausal sample, body image improved, as this group displayed body image scores close to the premenopausal level. In addition, sexual dissatisfaction was significantly increased in the perimenopausal and postmenopausal samples, which is compatible with the concept that higher body appreciation positively predicted sexual function. We conclude that body image dissatisfaction reaches a maximum during the perimenopausal phase, before returning to a level nearly identical between the premenopausal and the postmenopausal phases.     

Being a Foster-to-Adopt Parent: Experiences of (Un)certainty and Their Influence on the Sense of Being the Parent

The Mixed-Bank Program (Quebec, Canada) is based on concurrent planning principles. While the primary goal of this placement is reunification of the child with their birth parents, the low probability of this happening calls for simultaneously planning for an alternative solution, such as adoption. As a result, foster-to-adopt families have to deal with the uncertainty of the adoptability of the child and having no legal status nor control over the situation. In a qualitative study focusing on understanding how foster families from the Mixed-Bank Program develop the sense of being the parent of the child they care for, 25 semi-structured interviews with foster parents from 20 different families were conducted. As part of grounded theory methodology, a typology of profiles according to the level of uncertainty was constructed: (1) experience of certainty, (2) experience of momentary uncertainty, and (3) chronic uncertainty. This article presents these profiles and discusses the following challenges: the willingness to settle for permanence without adoption in all profiles, the link between the level of uncertainty and the assiduity of birth parents to supervised visits with the child, and the lack of power and control over the fulfillment of the goal of having or completing a family.