Literature that describes the prevalence of inherited red-green color deficiency in different populations is reviewed. Large random population surveys show that the prevalence of deficiency in European Caucasians is about 8% in men and about 0.4% in women and between 4% and 6.5% in men of Chinese and Japanese ethnicity. However, the male: female prevalence ratio is markedly different in Europeans and Asians. Recent surveys suggest that the prevalence is rising in men of African ethnicity and in geographic areas that have been settled by incoming migrants. It is proposed that founder events and genetic drift, rather than natural selection, are the cause of these differences.

Radiocarbon data suggest the need to reconsider current dates and assumptions for contact-era Iroquoian history.

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The accuracy of three new pseudoisochromatic tests for detecting red-green colour deficiency was assessed. These were the Ishihara plates, the Ishihara test for 'unlettered persons' and Ohkuma's test cards. We examined 500 subjects; 471 normal trichromats and 29 colour-deficient people. Results obtained for the 1989 edition of the Ishihara plates were compared with the 9th edition and the most efficient plates identified. Although normal trichromats may be expected to make several interpretive misreadings, the Ishihara plates were found to be superior to the 9th edition and to the Ohkuma test (1986) for colour vision screening. The new symbol designs of the Ishihara plates for 'unlettered persons' (1990) were found to be very effective for colour vision screening, and a further study with young children is proposed. The 38 plate 1989 edition of the Ishihara test is recommended for use in clinical practice. The designs included in the concise 24 plate edition and the new abbreviated 14 plate edition are not selected from the point of view of accuracy and more reliable results are obtained if the full test is given or if the practitioner shows only the most efficient designs.

This paper explores processes of settlement aggregation among ancestral Huron-Wendat populations in south-central Ontario, Canada. During the fifteenth century A.D., numerous small communities came together, forming large, fortified village aggregates. In order to understand these processes a multiscalar analytical approach was combined with a conceptual framework emphasizing cross-cultural perspectives on coalescent societies, the archaeology of communities, and historical trajectories of societal change. Regional settlement data are presented to illustrate the movement and increasing size of settlements. In order to determine how individual coalescent communities were formed and maintained, a single village relocation sequence is examined in detail. This sequence illustrates how people constructed, inhabited, and negotiated domestic and public spaces in these new community aggregates. Detailed analyses of the occupational histories of these sites point to the creation of new community-based identities, corporate decision-making structures, and increasing social integration over time. The results of this study demonstrate that while settlement aggregation can be documented at the regional level, only detailed intrasite analyses can identify the small-scale changes in practice that reflect the lived experience of coalescence.

This article presents results to date of the Dating Iroquoia project. Our objective is to develop high-precision radiocarbon chronologies for northeastern North American archaeology. Here, we employ Bayesian chronological modeling of 184 AMS radiocarbon dates derived from 42 Northern Iroquoian village sites in five regional sequences in order to construct new date estimates. The resulting revised chronology demands a rethinking of key assumptions about cultural process in the region regarding the directionality and timing of processes of coalescence and conflict and the introduction of European trade goods. The results suggest that internal conflict may have preceded confederacy formation among the Haudenosaunee but not the Wendat, as has been previously assumed. External conflict, previously thought to have begun in the early seventeenth century, began more than a century earlier. New data also indicate that the timing and distribution of European materials were more variable between communities than acknowledged by the logic underlying traditional trade-good chronologies. This enhanced chronological resolution permits the development and application of archaeological theories that center the lived experiences and relational histories of Iroquoian communities, as opposed to the generalized thinking that has dominated past explanatory frameworks.

The Ishihara test is the most widely used screening test for red-green colour deficiency. Results obtained by 401 people with red-green colour deficiency show that the combined sensitivity of the Transformation and Vanishing plates of the 38 plate Edition of the Ishihara plates is 95.5% on eight errors, 97.5% on six errors and 99.0% on three errors. The Hidden digit designs only identified approximately 50% of colour-deficient subjects. The protan/deutan classification plates were found to be more effective for deutans than for protans. No classification was obtained for 18% of protanopes and 3% of deuteranopes who saw neither figure on classification plates; 40% of protanomalous trichromats and 37.5% of deuteranomalous trichromats saw both classification figures and were classified on the relative luminance (clarity) of these figures. The specificity of the Ishihara test was determined in a previous study (Birch and McKeever, 1993) and the results combined with the present data to obtain the overall efficiency of the Ishihara plates for a representative cross section of colour-deficient subjects. © 1997 The College of Optometrists. Published by

Objective: To determine whether histopathologists with deficient colour vision make more errors in slide interpretation than those with normal colour vision. Design: Examination of projected transparencies of histopathological slides under standardised conditions by subjects whose colour discriminating ability was accurately assessed. Setting: Departments of histopathology in 45 hospitals in the United Kingdom.