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Glenda Cox

Bio: Glenda Cox is an academic researcher from University of Cape Town. The author has contributed to research in topics: Open educational resources & Open education. The author has an hindex of 12, co-authored 23 publications receiving 650 citations.

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Journal ArticleDOI
TL;DR: Isotopic analysis of skeletons excavated during the 1950s has confirmed that they are the remains of shipwreck victims: slaves on board the Portuguese slaving brig Pacquet Real when it sank on 18 May 1818 as mentioned in this paper.
Abstract: Isotopic analysis of skeletons excavated during the 1950s has confirmed that they are the remains of shipwreck victims: slaves on board the Portuguese slaving brig Pacquet Real when it sank on 18 May 1818. Twenty-five slaves drowned and the remaining 133 became “Prize Negroes” at the Cape. The isotopic signatures are consistent with values expected for people living in an African village eating a terrestrially based diet. Analyses of different skeletal elements, i.e., teeth, long bone, and rib, are shown to be a valuable tool in tracing change or consistency in diet during a person's life, because different skeletal elements form at different stages of life and, subsequently, remodel at different rates. A comparison of isotope ratios from different skeletal elements indicates a change in diet in all these individuals, probably coincident with their enslavement. Variation between individuals in the isotopic composition of diets eaten early in life is sufficiently large to deduce heterogeneous origins for the group.

168 citations

Journal ArticleDOI
TL;DR: The roles of course design, group dynamics, and facilitation style in the successful use of online collaboration within primarily face-to-face courses, as well as the potential forOnline collaboration within a blended course design to facilitate more inclusive learning conversations than are possible with exclusively face- to-face interaction are considered.
Abstract: Residential universities are increasingly integrating online interaction within courses in the form of synchronous online chats, asynchronous online discussions and access to interactive resources. This article evaluates the educational effectiveness of online chats within a Humanities postgraduate course and a final year Commerce course. We consider the roles of course design, group dynamics, and facilitation style in the successful use of online collaboration within primarily face-to-face courses, as well as the potential for online collaboration within a blended course design to facilitate more inclusive learning conversations than are possible with exclusively face-to-face interaction.

116 citations

Journal ArticleDOI
TL;DR: Analysis of the stable carbon and nitrogen isotope ratios of burials in a colonial cemetery in Cape Town, South Africa, reveals life histories of the underclass there and is the first use of bone chemistry to reconstruct the lives of a mixed population of diverse origin, buried in a cosmopolitan colonial city.
Abstract: Analysis of the stable carbon and nitrogen isotope ratios of burials in a colonial cemetery in Cape Town, South Africa, reveals life histories of the underclass there. We are able to distinguish foreign from local-born people, and to infer social status, specifically slavery, by linking bone chemistry and somatic modification. This is the first use of bone chemistry to reconstruct the life histories of a mixed population of diverse origin, buried in a cosmopolitan colonial city. As such, it may be used as a guide for future work in other colonial sites.

75 citations

Journal ArticleDOI
TL;DR: In this paper, the authors focus on a project to innovate the use of wikis for collaborative writing within student groups in a final-year undergraduate political science course, and raise questions concerning the nature and limits of lecturer and tutor power to deliver transformative educational innovations in relation to the capacity of students to embrace, comply with, or resist such innovation.

75 citations

Journal ArticleDOI
TL;DR: The results indicate that the bone density fractionation method is applicable to archaeological material, here extending to a maximum of 5,000 years BP, and that collagen can successfully be extracted from such fractions.
Abstract: A number of recent studies have attempted to trace diet at different stages of an individual's life by comparing isotope ratios of bone from different gross anatomical sites within the skeleton. In this study we develop this approach further by separating bone of differing mineral densities within one skeletal element, where each density fraction represents a different period of time. Isotope ratios are measured for these fractions. Each density fraction represents a period of bone formation and maturation, where younger (more recently formed) bone is less well-mineralized and therefore less dense than relatively older packets of bone. In an adult, bone is therefore able to partition approximately the last 15 years of life. Bone fractions were recovered by stepped ultracentrifugation in a series of organic solvents of increasing density, and then collagen was recovered by decalcification in dilute acid, and stable carbon isotope ratios (13C/12C) were measured. Bone density microstructure was checked for bacterial remodelling using backscattered electron imaging in a scanning electron microscope. Our results indicate that the bone density fractionation method is applicable to archaeological material, here extending to a maximum of 5,000 years BP, and that collagen can successfully be extracted from such fractions. The carbon isotope values for bone fractions of different densities patterned out as expected in one modern control bone and in specimens from five archaeological human skeletons, including three precolonial hunter-gatherers and two 18th/19th century individuals. The latter two are known (from previous assessments) to have undergone marked changes in diet during their lifetimes. Postmortem alteration was evident in some of the specimens examined. The bone density fractionation approach has allowed greater resolution of diet than has hitherto been possible and has provided access to the elusive last years and months of an individual's life. Am J Phys Anthropol 116:66–79, 2001. © 2001 Wiley-Liss, Inc.

68 citations


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01 Jan 1980
TL;DR: In this article, the influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition and found that the variability of the relationship between the δ^(15)N values of animals and their diets is greater for different individuals raised on the same diet than for the same species raised on different diets.
Abstract: The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

5,548 citations

01 Oct 2006

1,866 citations

Journal ArticleDOI
TL;DR: Strontium isotope analysis of archaeological skeletons has provided useful and exciting results in archaeology in the last 20 years, particularly by characterizing past human migration and mobility as mentioned in this paper.
Abstract: Strontium isotope analysis of archaeological skeletons has provided useful and exciting results in archaeology in the last 20 years, particularly by characterizing past human migration and mobility. This review covers the biogeochemical background, including the origin of strontium isotope compositions in rocks, weathering and hydrologic cycles that transport strontium, and biopurification of strontium from to soils, to plants, to animals and finally into the human skeleton, which is subject to diagenesis after burial. Spatial heterogeneity and mixing relations must often be accounted for, rather than simply ``matching'' a measured strontium isotope value to a presumed single-valued geologic source. The successes, limitations and future potential of the strontium isotope technique are illustrated through case studies from geochemistry, biogeochemistry, ecology and archaeology.

947 citations

Journal ArticleDOI
TL;DR: If bone is considered as a composite of collagen (protein) and bioapatite (mineral), then three pathways of diagenesis are identified: (1) chemical deterioration of the organic phase; (2) chemical deteriorated of the mineral phase; and (3) (micro) biological attack of the composite.
Abstract: If bone is considered as a composite of collagen (protein) and bioapatite (mineral), then three pathways of diagenesis are identified: (1) chemical deterioration of the organic phase; (2) chemical deterioration of the mineral phase; and (3) (micro) biological attack of the composite. The first of these three pathways is relatively unusual and will only occur in environments that are geochemically stable for bone mineral. However, because rates of biomolecular deterioration in the burial environment are slow, such bones would yield useful biomolecular information. In most environments, bones are not in thermodynamic equilibrium with the soil solution, and undergo chemical deterioration (path 2). Dissolution of the mineral exposes collagen to biodeterioration, and in most cases the initial phase of dissolution will be followed by microbial attack (path 3). Biological attack (3) also proceeds by initial demineralization; therefore paths 2 and 3 are functionally equivalent. However,in a bone that follows path 3 the damage is more localized than in path 2, and regions equivalent to path 1 may therefore exist outside these zones of destruction. Other biomolecules, such as blood proteins, cellular lipids and DNA, exist within the physiological spaces within bone.For these biomolecules, death history may be particularly important for their survival.

523 citations