Reduction in Predator Defense in the Presence of Neighbors in a Colonial Fish

Predation pressure has long been considered a leading explanation of colonies, where close neighbors may reduce predation via dilution, alarming or group predator attacks. Attacking predators may be costly in terms of energy and survival, leading to the question of how neighbors contribute to predator deterrence in relationship to each other. Two hypotheses explaining the relative efforts made by neighbors are byproduct-mutualism, which occurs when breeders inadvertently attack predators by defending their nests, and reciprocity, which occurs when breeders deliberately exchange predator defense efforts with neighbors. Most studies investigating group nest defense have been performed with birds. However, colonial fish may constitute a more practical model system for an experimental approach because of the greater ability of researchers to manipulate their environment. We investigated in the colonial fish, Neolamprologus caudopunctatus, whether prospecting pairs preferred to breed near conspecifics or solitarily, and how breeders invested in anti-predator defense in relation to neighbors. In a simple choice test, prospecting pairs selected breeding sites close to neighbors versus a solitary site. Predators were then sequentially presented to the newly established test pairs, the previously established stimulus pairs or in between the two pairs. Test pairs attacked the predator eight times more frequently when they were presented on their non-neighbor side compared to between the two breeding sites, where stimulus pairs maintained high attack rates. Thus, by joining an established pair, test pairs were able to reduce their anti-predator efforts near neighbors, at no apparent cost to the stimulus pairs. These findings are unlikely to be explained by reciprocity or byproduct-mutualism. Our results instead suggest a commensal relationship in which new pairs exploit the high anti-predator efforts of established pairs, which invest similarly with or without neighbors. Further studies are needed to determine the scope of commensalism as an anti-predator strategy in colonial animals.

Late diagnosis of fucosidosis in a child with progressive fixed dystonia, bilateral pallidal lesions and red spots on the skin

Fucosidosis is a rare lysosomal storage disease. A 14-year-old girl is presented, with recurrent infections, progressive dystonic movement disorder and mental retardation with onset in early childhood. The clinical picture was also marked by mild morphologic features, but absent dysostosis multiplex and organomegaly. MRI images at 6.5 years of age were reminiscent of pallidal iron deposition ("eye-of-the-tiger" sign) seen in neurodegeneration with brain iron accumulation (NBIA) disorders. Progressively spreading angiokeratoma corporis diffusum led to the correct diagnosis. This case extends the scope of clinical and neuroradiological manifestations of fucosidosis.

What is the Role of Universities in High-tech Economic Development? The Case of Portland, Oregon, and Washington, DC

This paper focuses on two regions in the United States that have emerged as high-technology regions in the absence of major research universities. The case of Portland's Silicon Forest is compared to Washington, DC. In both regions, high-technology economies grew because of industrial restructuring processes. The paper argues that in both regions other actors—such as firms and government laboratories—spurred the development of knowledge-based economies and catalysed the engagement of higher education institutions in economic development. The paper confirms and advances the triple helix model of university–government–industry relationships and posits that future studies have to examine degrees of university-region engagement.