TESTING FOR CAUSALITY BETWEEN PRODUCTIVITY AND AGGLOMERATION ECONOMIES

ABSTRACT The productivity effects of agglomeration economies are often treated as endogenous in empirical work due to the potential for reverse causality. The extent to which these relationships are actually simultaneously determined, however, remains largely unobserved. This paper estimates panel data vector autoregressions for different sectors of the economy to test for bidirectional causality between productivity and both localization and urbanization economies. The aim is to address some key questions that will help to identify the extent of the endogeneity problem. Can we actually observe bidirectionality in the data? Does it feature more for some industries than for others? Is it more prevalent for localization or urbanization economies? The results show that agglomeration economies are not strictly unidirectional and that higher levels of productivity can induce growth in the scale of local urban and industrial environments. The paper discusses the difficulties that these issues pose for the estimation of agglomeration economies.     

Oxygen isotope seasonality in a temperate estuarine shell midden: a case study from CA-ALA-17 on the San Francisco Bay,California

Seasonality determination using stable oxygen isotope (δ¹⁸O) analyses in archaeological mollusk shell has been largely limited to aquatic settings where one of the two factors that control shell δ¹⁸O – water δ¹⁸O (or salinity) and temperature – is assumed to be constant. Open coastal marine environments reflect the former situation, and tropical estuaries constitute the latter. In an effort to expand stable isotope seasonality to an ecological setting where neither variable remains constant, we present a model of annual shell δ¹⁸O cycle of aragonite deposition derived from instrumental data on salinity and temperature from San Francisco Bay, California. The predicted range of modeled shell δ¹⁸O is consistent with observed δ¹⁸O values in prehistoric and modern shells when local conditions are considered. Measurements of δ¹⁸O taken at 0 mm and 2 mm from the terminal growth margin were made on 36 archaeological specimens of Macoma nasuta from a late Holocene hunter-gatherer site CA-ALA-17, and season of collection was inferred using the shell δ¹⁸O model. We conclude that shellfish exploitation occurred through the year with the exception of fall, which may indicate scheduling conflicts with acorn harvesting or other seasonally abundant resources elsewhere. The model supports the feasibility of stable isotope seasonality studies in temperate estuaries, provided that instrumental records are available to quantify the relevant water conditions at appropriate spatial and temporal scales.     

Counselling Citizens and Producing Patronage: AIDS Treatment in South African and Ugandan Clinics

Global health interventions to provide antiretroviral (ARV) drug treatment for people living with HIV/AIDS in developing countries have linked global and local actors in unprecedented ways. These uneven relationships have been described as creating new forms of citizenship that challenge the liberal understanding of rights and responsibilities bestowed by the state. A comparative case study based on fieldwork from South Africa and Uganda suggests different theoretical understandings of the link between technologies of AIDS treatment and relationships of belonging. Yet, ethnographic data from local clinics in both countries point to similarities that exist across AIDS interventions, and to the importance of counsellors in negotiating the rules of ARVs. Neither patients living with HIV nor the local providers of their AIDS treatment are ‘bare life’ subjects to be acted upon by a global development intervention. As ARV technologies are increasingly prescribed in developing country clinics, diverse social relationships are taught and negotiated as part of the pedagogy of biopolitics. The following discussion demonstrates how local counsellors and clients negotiate the rules of AIDS treatment together for mutual benefit. The article concludes that AIDS treatment creates relationships of therapeutic citizenship and clientship in ways that constrain the possibilities of citizenship and development.     

Where East Meets West: The Formative in Mexico’s Central Highlands

Mexico’s Central Highlands form one of Mesoamerica’s fundamental cultural seams, a point of overlap between two traditions, one to the east and the other to the west. Although this area is usually included in the west, it can be more productively viewed as an interface, the physical space where people, goods, and ideas passed from one side to the other, and thus it holds many keys for our understanding of emerging social complexity in Mesoamerica. In reviewing the last two decades of Formative period (1500 BC–AD 100) research in this crucial territory, we focus on themes that reveal the variation and dynamism of interregional interaction, including the formation of regional traditions, exchange systems, and foreign “influence,” and others that help contextualize the events and processes of that time, like household studies and environmental degradation. We stress that this part of Mexico is undergoing relentless development so time is of the essence if we are to broaden our perspectives on social evolution in the Central Highlands. This issue cannot be resolved by rescue and salvage work because it requires long-term, interdisciplinary projects to unravel multifaceted problems.     

Stable isotope analysis of dog,fox, and human diets at a Late Holocene Chumash village (CA-SRI-2) on Santa Rosa Island,California

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analyses of dog (Canis familiaris), island fox (Urocyon littoralis), and human bone collagen from CA-SRI-2 (AD 130–1830) on Santa Rosa Island, California provide a proxy of diet and the relationships between humans and these animals. Carbon isotopic signatures indicate that Native Americans and their dogs at CA-SRI-2 subsisted almost exclusively on marine resources, while the island fox ate primarily terrestrial foods. Nitrogen isotopes and archaeofaunal remains indicate that humans and dogs also ate higher trophic level foods, including finfishes, marine mammals, and seabirds with smaller amounts of shellfish. The CA-SRI-2 island foxes appear to have eaten higher amounts of terrestrial foods, similar to the diets observed in modern fox populations. These data generally confirm the commensal relationship assumed to exist between domesticated dogs and people, but the carbon isotopic composition of dogs is enriched ∼2‰ compared to humans. We hypothesize that the difference in carbon isotopes between dogs and humans may have resulted from a higher consumption of C3 plants with lower δ¹³C values by humans, or less likely from the ingestion by dogs of significant amounts of bone collagen, which is enriched by ∼4‰ over associated muscle.     

Using hearths for temper: petrographic analysis of Middle Woodland charcoal-tempered pottery in Northeast Florida

Charcoal-tempered pottery is uncommon in North America, but was produced with notable frequency in Northeast Florida from ca. AD 300–600. Thirty-six thin sections of pottery were analyzed by petrographic analysis and compared to 10 clay samples in order to characterize the paste of charcoal-tempered wares in terms of charcoal and mineralogical composition and abundance, assess the number of clay sources used to make the pottery, identify the species of wood represented in charcoal inclusions, and infer techniques of ceramic production. This analysis identified four temper categories, three texture groups, and three distinct clay resources used to make charcoal-tempered pottery, all of which were likely local to Northeast Florida. Identified wood taxa include pine (Pinus sp.), cedar (cf. Juniperus sp.), cypress (cf. Taxodium sp.), and sassafras (Sassafras albidum), with pine suspected to be the most common. These genera of charred wood, which exhibit minimal shrinkage in the samples, along with the prevalence of bone and grog inclusions, indicate that hearth contents were processed as temper, sometimes in combination with quartz sand. Potential reasons for the use of hearth contents as temper are considered.