Related variety and the dynamics of European photonic clusters

This article aims at assessing the role of related variety, that is, the relatedness of knowledge bases used by different sectors within a region, as a major driver of clusters’ development. Some recent theoretical papers underline the role of clusters as ‘knowledge platforms’ organizing the recombination of technologies in overlapping industries, following the seminal definition of clusters by Porter as ‘geographic concentrations of linked industries’. In order to investigate the role of related variety in cluster dynamics, we analyse the patterns of development of clusters specializing in photonics in Europe. Photonics constitutes a new and rapidly evolving set of technologies with a high expected degree of technological recombination. However, due to inadequate traditional sectoral classifications, we propose an original method to delineate the perimeter of photonics in patent databases. A two-step algorithm is then used to identify systematically photonic clusters in Western Europe at the local level. In the last part of the paper, a typology of technological trajectories of clusters over the last decades is developed and then correlated with a set of quantitative measures of technological relatedness. The results highly confirm the role of related variety as a major driver of success, particularly for the biggest European clusters.     

A Covering Tour Model for Planning Mobile Health Care Facilities in SuhumDistrict, Ghama

The provision of adequate primary health care in developing countries is often troublesome. The problem is to provide a sufficient number of facilities to be geographically accessible, yet few enough to be properly stocked and staffed. In many less developed countries accessibility problems are exacerbated by extensive rainy seasons in which travel is only possible on paved roads. Using the covering tour model we investigate the use of mobile facilities to resolve this dilemma in Suhum District, Ghana. The model minimizes a mobile facility's travel while serving all population centers within range of a feasible stop. Computational results show that in the rainy season the model cannot provide full coverage; over six percent of the population is beyond a covering distance of eight kilometers. In the dry season, 99 percent of the population can be served by a tour at a covering distance of seven kilometers.Beyond a distance of four kilometers, the dry season problem becomes a trade-off between the distance traveled by healthcare patrons and mobile facilities. These results illustrate the importance of flexibility of mobile systems: if accessibility cannot be provided in all seasons it may still be provided at favorable times of the year.     

Theory,Practice, Life: Rethinking Americanist Anthropology for the Twenty- First Century

Collier, Jane Fishburne, and Sylvia Junko Yanagisako, eds. Gender and Kinship: Essays Toward a Unified Analysis. Stanford: Stanford University Press, 1987. xiii + 369 pp. including references. $39.50 cloth.

Lamphere, Louise. From Working Daughters to Working Mothers: Immigrant Women in a New England Industrial Community. Ithaca: Cornell University Press, 1987. xviii + 390 pp. including references and index. $45.00 cloth; $14.95 paper.

Shaver, Phillip, and Clyde Hendrick, eds. Sex and Gender. Newbury Park, California: Sage Publications, 1987. 328 pp. including references. No price.     

Nahal Lavan 108: A Pre-Pottery Neolithic a Site in the Western Negev,Israel

Abstract

Although the recent publication of the results of excavation and restoration in the Siq at Petra by the Petra National Trust has thrown welcome light on the hydraulic engineering skills of the Nabataeans, it is suggested here that the conclusions reached by the authors regarding the chronology of those works are not necessarily correct and should not be accepted as definitive. It is shown that the interpretation of the ceramic evidence is faulty and that other, epigraphic, evidence is ignored. In particular, it is argued that the major works — the dam and the tunnel — as well as the paved road through the Siq, may be as late as, or even later than, the middle of the 1st century AD, rather than the late 1st century BC, as the authors assume. It is further suggested that this could also be the date of the Khazneh, and that this may be indicated also by the recent discovery of earlier tomb façades beneath the Khazneh.