Surviving in a Competitive Spatial Market: The Threshold Capture Model

Many facility location decision models ignore the fact that for a facility to survive it needs a minimum demand level to cover costs. In this paper we present a decision model for a firm that wishes to enter a spatial market where there are several competitors already located. This market is such that for each outlet there is a demand threshold level that has to be achieved in order to survive. The firm wishes to know where to locate its outlets so as to maximize its market share taking into account the threshold level. It may happen that due to this new entrance, some competitors will not be able to meet the threshold and therefore will disappear. A formulation is presented together with a heuristic solution method and computational experience.     

A Voice for Black Interests: Congressional Black Caucus Cohesion and Bill Cosponsorship

This study enhances our understanding of the vexing dilemma (i.e., the crosspressures emanating from individual goals and collective aspirations) confronting black legislators. Extant research based on roll call votes or on interest group scores that are also based on roll call votes is limited in what it can tell us about African-American representation in Congress. By examining African-American representatives' cosponsorship of legislation, this study uses a more accurate measure of members' legislative behavior and thus overcomes the "censored sample problem" associated with roll call data. Bill cosponsorship is a good indicator of a representative's intensity of commitment to constituent interests. We examine public bills cosponsored by African-American representatives from 1971 through 1993. The analysis finds that the cohesiveness of the Congressional Black Caucus (CBC) transcends policy arenas, notwithstanding higher rates of cosponsorship on social issues, and that the number of bills cosponsored by the CBC is noticeably higher after 1982. In addition, analysis suggests that CBC members, just like all members of Congress, respond to the structure that governs the House and the political forces that shape their electoral fortunes.     

Cartographic,Geophysical and Diver Surveys of the Medieval Town Site at Dunwich,Suffolk, England

This paper presents the results of an integrated historical and geophysical survey of a medieval town lost through cliff recession and coastal inundation. Key objectives included evaluating historic maps in supporting the relocation and identification of major buildings, and applying integrated multibeam, side‐scan and sub‐bottom profiling to determine the location and extent of archaeological remains. The results demonstrate that cartographic sources from 1587 onwards can be a reliable source of data to guide geophysical survey. Integration of historical mapping with geophysical data enabled identification of the remains of two medieval structures, and the tentative identification of two others. © 2010 The Authors     

The Quaternary fossil record of the genus Testudo in the Iberian Peninsula. Archaeological implications and diachronic distribution in the western Mediterranean

This paper explores the presence of tortoise remains and its meaning in Palaeolithic archaeological contexts. We focus on two topics: (1) the presence or absence of the genus Testudo from the Early Pleistocene to the Holocene in SW Europe; and (2) the relationship between Testudo and the palaeoclimatic and palaeoenvironmental conditions diachronically. In order to address this objective, we collected published and unpublished data from different sites on the eastern Iberian Peninsula. The results obtained by this study demonstrate that Testudo hermanni was the only tortoise present in this area until recent times and its presence in archaeological sites is almost always related to anthropic activities. Finally, the disappearance of Testudo from archaeological sites in some areas is related to climatic changes and events that occurred during the last stages of the Pleistocene.     

Spatial and Socio-environmental Dynamics of Catalan Regional Planning from a Multivariate Statistical Analysis Using 1980s and 2000s Data

This article summarizes the protocol applied to analyse the spatial consequences of diverse regional plans included in the General Spatial Planning of Catalonia (GSPC) municipalities since 1985. The main aims of the GSPC were to achieve a more balanced distribution of population, avoiding Barcelona metropolitan region congestion, coastal overcrowding and mountain areas depopulation, and to improve mobility infrastructures and social welfare. The methodology used was based on factor analysis that reduced 30 socioeconomic and geographic variables provided by different sources into a smaller number of common factors. Afterwards a non-hierarchical clustering was employed to simplify the analysis of dynamics. The six first common factors retained in the model explained the 82.6% of total variance. After labelling them, six clusters were mapped to describe the most important dynamics: urban sprawl, urbanalization, depopulation, reterritorialization and coastalization. Finally, some socio-environmental consequences of such dynamics are discussed.     

The Style of Blugzeimat and the “Masks” of the Prehistoric Rock Art of the Western Sahara: New Evidence for Long-Distance Contacts

Blugzeimat is a prehistoric rock-art site in the Tiris region (southern Western Sahara), with more than 100 engraved slabs. The major portion of these engravings represents zoomorphs, anthropomorphs and non-figurative signs. Based on the absence of protohistoric texts, chariots or horse riders, and the probable depiction of a halberd, the age of these engravings may correspond to the first half of the second millennium BCE. The stylistic attributes of the engraved bovines, which are the most commonly represented subject, allow us to relate Blugzeimat to several sites with pecked engravings located in the Tiris (Western Sahara) and Adrar (north-western Mauritania) regions. In addition to this first stylistic and geographic delimitation, we have also been able to identify signs, traditionally designated as “masks” in the literature, which relate Blugzeimat to several sites with incised engravings located in the northern Saguia el Hamra basin. As incised and pecked engraving techniques have been regularly considered examples of unrelated rupestrian traditions in the Western Sahara, the engraving of these highly specific signs using both techniques allows us to question that paradigm. Finally, the long-distance thematic coincidence represented by the presence of such signs, in regions far from one another, provides additional evidence to refute the common idea of an absence or scarcity of cultural contacts between the north and south of the Western Sahara before the adoption of the horse and camel.     

Analysis of the Effect of Provisional Ties on the Construction and Current Deformation of Mallorca Cathedral

This article presents the analysis of the structure of Mallorca Cathedral taking into account the influence on the structural behavior of auxiliary iron ties used during the construction process. Recent studies (Roca et al. 2012, 2013) presented some hypotheses about the construction process of the cathedral. This article complements the previous results by considering the use of auxiliary ties as temporary stabilizing device during the construction. Evidence of the use of ties during the construction has been recognized after a comprehensive survey. The study of the role of such ties and the effect of their later removal are studied by a FE analysis carried out on a representative bay of the structure. The study includes a time-dependent FE analysis after the removal of the ties to assess the long-term structural behavior. The results of the numerical analysis are compared with the deformation trends identified by means of a recent monitoring campaign.     

Estimating Rapidity of Change in Complex Urban Systems: A Multidimensional,Local‐Scale Approach

This study illustrates an exploratory approach based on a Multiway Factor Analysis (MFA) to estimate rapidity of change in complex urban systems, based on “fast” and “slow” variables. The proposed methodology was applied to 18 socioeconomic indicators of long‐term (1960–2010) transformations in 115 municipalities of Athens’ metropolitan area (Greece), including demography, land‐use/planning, and urban form and functions. Athens was regarded as a dynamic urban area with diversified structures and functions at the local scale, expanding through a self‐organized pattern rather than a centralized planning strategy. Athens’ urban system was described using nine supplementary (topographic and territorial) variables and 30 independent indicators assessing the local context in recent times. Exploratory data analysis found an increasing connectedness and redundancy among socioeconomic indicators during the phase of largest urban expansion (1960–1990). Only the rate of population growth was classified as a “fast” variable for all five decades investigated. The overall rapidity of change was higher in 1960–1970, 1980–1990, and 2000–2010, decades that coincided with specific phases of urban expansion driven by migration inflow, second‐home suburbanization, and Olympic games, respectively. Rapidity of change was high for functional indicators during all five decades studied, while demography indicators changed more rapidly in the first three decades and land‐use/planning indicators in the last two decades. Rapidity of change was highest in peri‐urban municipalities with a highly diversified economic structure dominated by industry. Our methodology provides a comprehensive overview of the transformations of a complex urban system, quantifying low‐level indicators that are rarely assessed in the mainstream literature on urban studies. These results may contribute to design policies addressing complexity and promoting resilience in expanding metropolitan areas.