ESTIMATION PROBLEMS IN MODELS WITH SPATIAL WEIGHTING MATRICES WHICH HAVE BLOCKS OF EQUAL ELEMENTS*

ABSTRACT Spatial models whose weighting matrices have blocks of equal elements might be considered if units are viewed as equally distant within certain neighborhoods, but unrelated between neighborhoods. We give exact small sample results for such models that contain a spatially lagged‐dependent variable. We consider cases in which the data relate to one or more panels, for example, villages, schools, etc. Our results are consistent with large sample results given in Kelejian and Prucha (2002) but indicate a variety of issues they did not consider.     

A SPATIAL CLIFF‐ORD‐TYPE MODEL WITH HETEROSKEDASTIC INNOVATIONS: SMALL AND LARGE SAMPLE RESULTS*

ABSTRACT In this paper, we specify a linear Cliff‐and‐Ord‐type spatial model. The model allows for spatial lags in the dependent variable, the exogenous variables, and disturbances. The innovations in the disturbance process are assumed to be heteroskedastic with an unknown form. We formulate multistep GMM/IV‐type estimation procedures for the parameters of the model. We also give the limiting distributions for our suggested estimators and consistent estimators for their asymptotic variance‐covariance matrices. We conduct a Monte Carlo study to show that the derived large‐sample distribution provides a good approximation to the actual small‐sample distribution of our estimators.     

A comprehensive numerical chronology for the pre-Columbian cultures of the Palpa valleys,south coast of Peru

Before the arrival of the Spaniards in Peru in 1532, many different societies flourished in the coastal desert of southern Peru. Of these, one of the best known is the Nasca culture (living in the area between about 260 cal BC and 640 cal BC.), which created the famous geoglyphs on the desert floor. In this paper we present a numerical chronology for the cultural development in the valleys of Palpa, in the northern part of the Nazca region, which spans the time from the Archaic Period (starting there around 3760 cal BC) to the Late Intermediate Period (terminating with the arrival of the Spaniards in 1532 AD). The chronology is based on more than 150 ¹⁴C samples collected by our project from well-documented archaeological excavations of 17 different sites in and around Palpa. Thanks to the advanced AMS-¹⁴C dating technique, demanding only few milligrams of organic material, we could focus on samples of plants, like beans, corn, or reed, representing single years of growth or use, and also on delicate materials like straw from clay bricks (adobe) and textiles. All single ¹⁴C dates were combined to cultural phases using a Bayesian statistical model, implementing the a priori information of the archaeological contexts, and adopting the relative ceramic chronologies available for this area.     

Self-Organization in Urban Regeneration: A Two-Case Comparative Research

Urban regeneration processes in which local stakeholders take the lead are interesting for realizing tailor made and sustainable urban regeneration, but are also faced with serious difficulties. We use the concept of self-organization from complexity theory to examine the relationship between local stakeholders’ initiatives and vital urban regeneration processes. We conducted a two-case comparative research, Caterham Barracks and Broad Street Business Improvement Districts Birmingham (UK), in which local stakeholders take the lead. We analyse the evolution of these regeneration processes by using two different manifestations of self-organization: autopoietic and dissipative self-organization. We found that a balanced interplay between autopoietic and dissipative self-organization of local stakeholders is important for vital urban regeneration processes to establish. We elaborate four explanatory conditions for this interplay. These conditions provide at the one hand stability and identity development, but also the needed connections with established actors and institutions around urban regeneration and flexibility to adjust to evolving demands during the process of regeneration. However, consolidation of such initiatives does mean a challenge for existing structures for the government, market and society that will need to adapt and change their roles to new governance realities. In this way self-organizing processes become meaningful in the regeneration of urban areas.