The p‐Regions Problem. p‐区域问题

The p‐regions problem involves the aggregation or clustering of n small areas into p spatially contiguous regions while optimizing some criteria. The main objective of this article is to explore possible avenues for formulating this problem as a mixed integer‐programming (MIP) problem. The critical issue in formulating this problem is to ensure that each region is a spatially contiguous cluster of small areas. We introduce three MIP models for solving the p regions problem. Each model minimizes the sum of dissimilarities between all pairs of areas within each region while guaranteeing contiguity. Three strategies designed to ensure contiguity are presented: (1) an adaptation of the Miller, Tucker, and Zemlin tour‐breaking constraints developed for the traveling salesman problem; (2) the use of ordered‐area assignment variables based upon an extension of an approach by Cova and Church for the geographical site design problem; and (3) the use of flow constraints based upon an extension of work by Shirabe. We test the efficacy of each formulation as well as specify a strategy to reduce overall problem size.     

Subsistence variations and landscape use among maritime hunter-gatherers. A zooarchaeological analysis from the Beagle Channel (Tierra del Fuego,Argentina)

Changes in the exploitation of resources among prehistoric hunter-gatherer-fishers of the Beagle Channel (Southern South America) are examined in this paper. Archaeological investigations show the prevalence of maritime hunter-gatherer organization throughout the occupation of the region (ca. 6400 BP – 19th century). Notwithstanding, variations in the exploitation of different kind of animal resources have been detected, and a concomitant reorientation in the landscape use is then inferred. Zooarchaeological evidence from five shellmiddens is analyzed here: evenness measures and relative abundance prey types are used to evaluate such adjustments. Results indicate the major utilization of coastal and terrestrial ecozones and the predominance in the exploitation of mammals (pinnipeds and guanacos) in ancient occupations. While, during the Late Holocene an expansion in ranges of maritime mobility for subsistence is detected, which was associated with an increase in the representation of birds and fish in the zooarchaeological record.     

Building local nodes in a global sector: Clustering within the aeronautics industry in Montreal

This article analyzes the mechanisms through which metropolitan governance is established in Montreal's aeronautics sector, one of the most important and innovative industries in the region. The article also examines the role of lead firms, socio‐economic actors, and public agencies from a territorial point of view. It is established that on the one hand the existence of a small number of prime producers at the local level facilitates productive linkages among businesses through subcontracting, and on the other hand, the intensive participation of intermediate socio‐economic agencies and organizations ensures a metropolitan anchoring of the sector and creates a strong territorial identity among the players.     

A Static Nonlinear Procedure for the Evaluation of the Elastic Buckling of Anchored Steel Tanks Due to Earthquakes

Ground-supported steel tanks experienced extensive damage in past earthquakes. The failure of tanks in earthquakes may cause severe environmental damage and economic losses. This study deals with the evaluation of the elastic buckling of above-ground steel tanks anchored to the foundation due to seismic shaking. The proposed nonlinear static procedure is based on the capacity spectrum method (CSM) utilized for the seismic evaluation of buildings. Different from the standard CSM, the results are not the base shear and the maximum displacement of a characteristic point of the structure but the minimum value of the horizontal peak ground acceleration (PGA) that produces buckling in the tank shell. Three detailed finite element models of tank-liquid systems with height to diameter ratios H/D of 0.40, 0.63, and 0.95 are used to verify the methodology. The 1997 UBC design spectrum and response spectra of records of the 1986 El Salvador and 1966 Parkfield earthquakes are used as seismic demand. The estimates of the PGA for the occurrence of first elastic buckling obtained with the proposed nonlinear static procedure were quite accurate compared with those calculated with more elaborate dynamic buckling studies. For all the cases considered, the proposed methodology yielded slightly smaller values of the critical PGA for the first elastic buckling compared to the dynamic buckling results.     

Successive Earthquake-Tsunami Analysis to Develop Collapse Fragilities

Over the last half century, scientists and engineers have developed methods to better understand and mitigate the damage caused by tsunamis. According to U.S. Federal Emergency Management Agency (FEMA) P646, buildings in many regions, including the U.S. Pacific Northwest, will experience substantial ground shaking from an offshore earthquake that precedes a tsunami and then experience the tsunami forces themselves. Thus, both hazards should be considered in computing the damage and collapse risk to buildings. This article summarizes a basic approach to numerically consider the successive seismic and tsunami risk to buildings in near-field tsunami regions such as the U.S. Pacific Northwest.     

After the Nicaraguan Non‐Payment Crisis: Alternatives to Microfinance Narcissism

This article argues against ‘microfinance narcissism’ and calls for a re‐politicization of the microfinance paradigm. The dominant verdict on microcredit has undergone a damning transformation, from ‘magic bullet for poverty reduction’ to ‘cause of suicide’. Nowadays, both radical critics and mainstream voices deplore microcredit's negative impact on micro‐entrepreneurs. They argue for a reorientation where credit is targeted at established small and medium‐sized enterprises, particularly in rural areas. The crisis in microfinance worldwide, including burgeoning protests, are viewed as proof of the commercial derailment and/or misplaced faith in microfinance's positive social and economic impact on the poor. This article engages with this debate through a study of the Nicaraguan micro‐finance crisis. It challenges existing analyses that pin the crisis on agricultural over‐indebtedness, lack of due diligence, or Sandinista populist politics. Illustrating the dangers of neglecting the diverse nature of microfinance, it reveals the paradoxical outcomes of the crisis: a refocus on the urban at the expense of agricultural credit for small and medium enterprises and a consolidation of the power of national processing elites. Nicaragua's Non‐Payment Movement is also shown to be both a product of elite manipulation and an expression of legitimate resistance to an industry that turns a blind eye to the manner in which markets and politics constrain clients’ potential.     

Reception,wit, and the unity of Virgil's Georgics 1

This essay considers the ways in which the reception of Virgil's Georgics in eighteenth-century English verse may inform, enrich and complicate present-day readings of Virgil, focusing on questions raised by readers’ detection of wit or humorousness in Virgil and by the critical aim of discovering poetic unity in the Georgics.