Detecting Instability in Animal Social Networks: Genetic Fragmentation Is Associated with Social Instability in Rhesus Macaques

The persistence of biological systems requires evolved mechanisms which promote stability. Cohesive primate social groups are one example of stable biological systems, which persist in spite of regular conflict. We suggest that genetic relatedness and its associated kinship structure are a potential source of stability in primate social groups as kinship structure is an important organizing principle in many animal societies. We investigated the effect of average genetic relatedness per matrilineal family on the stability of matrilineal grooming and agonistic interactions in 48 matrilines from seven captive groups of rhesus macaques. Matrilines with low average genetic relatedness show increased family-level instability such as: more sub-grouping in their matrilineal groom network, more frequent fighting with kin, and higher rates of wounding. Family-level instability in multiple matrilines within a group is further associated with group-level instability such as increased wounding. Stability appears to arise from the presence of clear matrilineal structure in the rhesus macaque group hierarchy, which is derived from cohesion among kin in their affiliative and agonistic interactions with each other. We conclude that genetic relatedness and kinship structure are an important source of group stability in animal societies, particularly when dominance and/or affilative interactions are typically governed by kinship

Radiologic diagnosis of Barrett's esophagus: Critical analysis of 65 cases

A recent increase in the number of Barrett's esophagis being diagnosed is probably directly related to a proportional increase in endoscopic biopsies of the esophagus and awareness of premalignant potential of Barrett's mucosa. While the endoscopist can detect Barrett's mucosa with fair degree of accuracy, the radiologic diagnosis of Barrett's esophagus still remains a diagnostic challenge despite several well established radiologic features. We reviewed 65 patients with pathologically proven Barrett's esophagus and found a wide spectrum of radiologic features. These include hiatus hernia in 49, gastroesophageal reflux in 38, strictures in 32, esophagitis in 20, and characteristic Barrett's ulcer in 12. In addition ascending or migrating strictures were found in 10, mucosal pattern simulating areae gastricae in 5, cricopharyngeal dysfunction in 4, and fixed spiral folds in 3 patients. This constellation of radiologic features, some of which have not been previously emphasized, should further assist radiologists in suggesting the diagnosis of Barrett's esophagus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48125/1/261_2005_Article_BF02035052.pd