Bereavement Research: An Historical Introduction

Early research in the field of bereavement and widowhood was often problem generated and focused on intrapersonal issues such as health consequences. More recent research has emphasized that, to understand the grieving individual, we must also understand the social context in which the bereavement occurred and in which recovery must progress. This introduction traces the historical development of theory, empirical research, and methodology in the field, and places current developments in perspective. The papers in this issue underline the complexity of the bereavement phenomenon, and the need for conceptual perspectives with which to understand the cultural, socioeconomic, interpersonal, and physiological determinants of grief, mourning, and recovery.     

Combinatorics of TCP reordering

We study a combinatorial problem motivated by a receiver-oriented model of TCP traffic from Istrate et al. (2006), that incorporates information on both arrival times, and the dynamics of packet IDs. An important component of this model is a many-to-one mapping FB from sequences of IDs into a sequence of buffer sizes. We show that: i) Given a buffer sequence B, constructing a sequence A of IDs that belongs to the preimage of B is no harder than finding matchings in bipartite graph. ii) Counting the number of sequences A of packet IDs that belong to the preimage of B can be done in linear time in the special case when there exists a constant upper bound on the maximum entry in B. iii) This problem also has a fully polynomial randomized approximation scheme when we have a constant upper bound on the number of repeats in the packet sequences in the preimage. We also provide experimental evidence that the two previous results suffice to efficiently count the number of preimages for buffer sequences observed in real TCP data.     

Moral philosophy has much more to offer

Moral philosophy is a rich tradition that contains many alternative approaches to determining what is right and wrong. A limited account that only considers (hedonistic) utilitarianism and deontology cannot do justice to moral philosophy. It is necessary to also consider the many other general-purpose moral theories that have been proposed, as well as the approaches developed in various branches of applied ethics, such as healthcare ethics, the ethics of technology, and the ethics of risk.