König's Infinity Lemma and Beth's Tree Theorem

König, D. [1926. ‘Sur les correspondances multivoques des ensembles’, Fundamenta Mathematica, 8, 114–34] includes a result subsequently called König's Infinity Lemma. Konig, D. [1927. ‘Über eine Schlussweise aus dem Endlichen ins Unendliche’, Acta Litterarum ac Scientiarum, Szeged, 3, 121–30] includes a graph theoretic formulation: an infinite, locally finite and connected (undirected) graph includes an infinite path. Contemporary applications of the infinity lemma in logic frequently refer to a consequence of the infinity lemma: an infinite, locally finite (undirected) tree with a root has a infinite branch. This tree lemma can be traced to [Beth, E. W. 1955. ‘Semantic entailment and formal derivability’, Mededelingen der Kon. Ned. Akad. v. Wet., new series 18, 13, 309–42]. It is argued that Beth independently discovered the tree lemma in the early 1950s and that it was later recognized among logicians that Beth's result was a consequence of the infinity lemma. The equivalence of these lemmas is an easy consequence of a well known result in graph theory: every connected, locally finite graph has among its partial subgraphs a spanning tree.     

A systematic review of research on religion and spirituality in the Journal of Traumatic Stress: 1990–1999

Surveys reveal that religion and spirituality are highly valuable to many people in times of crisis, trauma, and grief. The relationship between coping with trauma and the use of various spiritual beliefs is well established. The importance of clergy in trauma recovery is also well documented. A review of the 469 research and non-research articles published between 1990 and 1999 in the Journal of Traumatic Stress revealed that 8.7% (6/69) of non-research articles, 4.1% (15/366) of quantitative research articles and 2.9% (1/34) of qualitative research articles considered religion or spirituality in their work. Analysis of variance found a significant overall increase in the percentage of articles that mentioned religion/spirituality between the first half (1990–1994) and the second half (1995–1999) of the study period. The results are discussed in the context of the trauma research and in comparison to related disciplines. Recommendations for future research and clinical application are suggested for both traumatologists and religious scholars.     

Rational decision‐making among male street prostitutes

This ethnographic study examines the lives of 18 young male street prostitutes. The focus of this study is to identify the benefits and liabilities associated with this activity by grounding the decision to engage in this behavior in a rational choice perspective. Benefits identified include financial gain, sexual pleasure, control of work schedule, and affection. The liabilities include fear of arrest, potential for violence, having sex with undesirable people, and not being paid for services rendered. This study demonstrates that the decision to engage in street prostitution is a complicated process that involves the weighing of the perceived benefits against the perceived risks.