Development of Trigger Levels to Assess Catchment Disturbance on Stream Suspended Sediment Loads in the Magela Creek Catchment,Northern Territory,Australia

Trigger levels for fine suspended sediment (FSS) load in streams are required to identify rainfall-runoff events that have significantly elevated FSS loads, compared with expected background loads, as a result of catchment disturbance. Stream FSS load data collected in the mine-impacted Magela Creek catchment in the wet-dry tropics were used to derive water quality management trigger levels for two approaches – a Before-After-Control-Impact Paired difference design (BACIP) and a regression relationship between observed FSS load and corresponding event discharge characteristics. The results indicate that both the BACIP and regression relationship approaches behave similarly, with similar FSS load events elevated above trigger levels. Notwithstanding this, it is recommended that in order to reliably assess the location and magnitude of a catchment disturbance on FSS load, a combination of BACIP and regression relationship approaches must be adopted. In this study, an event with a FSS load above trigger levels associated with both BACIP and the regression relationship fitted for the downstream site is considered to be significantly elevated as a result of a disturbance within the mine-impacted region. While this technique cannot conclusively determine whether the cause of the disturbance is mine-related or natural (such as fire or bank erosion), it is an efficient statistical method of identifying events that warrant further investigation and management action, if required.     

Neutron activation analysis of fine grey pottery from Conimbriga,Santa Olaia and Tavarede,Portugal

The concentrations of two major elements and thirteen trace elements in 73 selected sherds of fine grey ware from the Iron Age and Roman period, excavated at Conimbriga, Santa Olaia and Tavarede, Portugal, were determined by instrumental neutron activation analysis. These concentrations were used to calculate distance matrices which were then subjected to cluster analysis employing SAHN and k-means methods, as well as to principal components analysis, to group the sherds according to the overall similarity of their compositional characteristics. The results showed that equivalent groupings appeared regardless of the taxonomic method used. Two major clusters were recognized corresponding to two different sites, namely Conimbriga and Santa Olaia, suggesting that the ceramics from these sites were made locally. No significant differences in compositional patterns were observed between iron age and roman sherds from Conimbriga.     

Geographical structure in nineteenth-century urban retailing: Milwaukee, 1836–1890

This study explores the spatial structure of retailing in Milwaukee, Wisconsin, in the era before the introduction of the electric streetcar in 1890. It uses city directory listings to chart changes in the numbers and types of retail outlets, their degree of nucleation and the functional complexity of such nucleations. The evidence suggests the early appearance of non-central retailing, the rapid dispersal of high as well as low order goods to non-central sites and the early emergence initially of a three-level and then, by 1870, a four-level hierarchy of shopping clusters. The pattern of retail clustering varied with the class and ethnic character of neighbourhoods, and clusters gravitated toward major arterial routes even in the pre-mass transit ear. Urban retailing in the second half of the nineteenth century was neither randomly dispersed nor over-whelmingly concentrated in a single central retail district, but developed a spatial hierarchy that clearly anticipated modern patterns.     

Fear and loathing in Kansas City: Political harassment and the making of moderates in America's abortion wars (Respond to this article at http://www.therai.org.uk/at/debate)

The pro‐life movement regularly employs tactics of political harassment in its campaign against abortion. As the murder of the controversial abortion doctor George Tiller in Wichita, Kansas, demonstrated last year, such tactics often betray a potential for violence. This paper explores how the militant tactics of the pro‐life movement in the 1990s have contributed to the formation of a ‘new’ political identity in Kansas politics: that of the moderate Republican. But for those that seek to counter‐mobilize against the Christian right, the political stakes remain high.     

Buried assumptions: Some problems in the interpretation of the “Younger Fill” raised by recent data from Greece

A distinctive “Younger Fill” has been identified in the Mediterranean and adjacent regions. The dominant explanation for it is that of climatic change, first advanced by Vita-Finzi in 1960. Recent work on Greece by Bintliff appears to support the hypothesis. However, there are weaknesses. The present paper isolates the assumptions upon which the climatic hypothesis rests, particularly the notion of synchroneity and the apparent need for a universal mechanism. It sets out the grounds for scepticism, which include the ambiguity of the data, and attempts to evaluate the recent evidence from Greece. The paper then proceeds to argue that an anthropogenic origin cannot be ruled out and that it merits serious consideration. Criteria are suggested which the reinstated explanation would need to meet.