Measuring Space-Time Accessibility Benefits within Transportation Networks: Basic Theory and Computational Procedures

Accessibility is a fundamental but often neglected concept in transportation analysis and planning. Three complementary views of accessibility have evolved in the literature. The first is the constraints-oriented approach, best implemented by Hägerstrand's space-time prisms. The second perspective follows a spatial interaction framework and derives “attraction-accessibility measures” that compare destinations' attractiveness with the travel costs required. A third approach measures the benefit provided to individuals by the transportation/land-use system. This paper reconciles the three complementary approaches by deriving space-time accessibility and benefit measures that are consistent with the rigorous Weibull axiomatic framework for accessibility measures. This research also develops computational procedures for calculating these measures within network structures. This provides realistic accessibility measures that reflect the locations, distances, and travel velocities allowed by an urban transportation network. Since their computational burdens are reasonable, they can be applied at the urban scale using a GIS.     

Bedding, hearths, and site maintenance in the Middle Stone Age of Sibudu Cave, KwaZulu-Natal, South Africa

Micromorphological analysis of sediments from the Middle Stone Age site of Sibudu Cave, KwaZulu-Natal, South Africa, provides a high-resolution sequence and evidence of site formation processes of predominantly anthropogenic deposits. This methodology allows for a detailed interpretation of individual anthropogenic activities, including the construction of hearths and bedding and the maintenance of occupational surfaces through the sweep out of hearths and the repeated burning of bedding. This analysis also provides a context for evaluating other studies at the site relating to magnetic susceptibility, paleobotany, paleozoology, anthracology, and studies of ochre.     

The fish of Lake Titicaca: implications for archaeology and changing ecology through stable isotope analysis

Research on past human diets in the southern Lake Titicaca Basin has directed us to investigate the carbon and nitrogen stable isotopes of an important dietary element, fish. By completing a range of analyses on modern and archaeological fish remains, we contribute to two related issues regarding the application of stable isotope analysis of archaeological fish remains and in turn their place within human diet. The first issue is the potential carbon and nitrogen isotope values of prehistoric fish (and how these would impact human dietary isotopic data), and the second is the observed changes in the fish isotopes through time. Out of this work we provide quantitative isotope relationships between fish tissues with and without lipid extraction, and a qualitative analysis of the isotopic relationships between fish tissues, allowing archaeologists to understand these relationships and how these values can be applied in future research. We test a mathematical lipid normalization equation to examine whether future researchers will need to perform lipid extraction procedures for Lake Titicaca fish. We also analyze a number of aquatic plants to better understand the range of isotopic signatures of the Lake Titicaca ecosystem. We use these data to better understand prehistoric human diet and the role that fish may have played in the past as well as potential changes in local lake ecology through time.     

Oral History in a Wounded Country: Interactive Interviewing in South Africa

The utility of oral history has always seemed most evident whengreat change occurs. Political, social, and cultural upheavalscall for documentation of the direct participants, and the printedarchives inevitably reflect the viewpoint of the old regime.Nowhere has such change been more dramatic and breathtakingthan in South Africa since the 1990s, when decades of strictapartheid collapsed into a multiracial, multicultural societythat is now ruled by its former political prisoners. Although     

An experimental micromorphological investigation of bedding construction in the Middle Stone Age of Sibudu,South Africa

We conducted experiments to compare the micromorphological signatures of modern burnt sedge and grass bedding to laminated layers of carbonized material and phytoliths in Middle Stone Age deposits at the shelter, Sibudu. The experiments were designed to clarify the formation processes associated with the laminated layers and to investigate whether these previously identified layers of bedding were deliberately burned or not. The results indicate that the laminated layers were most likely produced by human activity related to the construction, maintenance and burning of bedding. Furthermore, our experiments demonstrate that large volumes of vegetal material could have produced the relatively thin, archaeological deposits of burnt bedding.