PANEL DATA MODELS WITH SPATIALLY DEPENDENT NESTED RANDOM EFFECTS

This paper focuses on panel data models combining spatial dependence with a nested (hierarchical) structure. We use a generalized moments estimator to estimate the spatial autoregressive parameter and the variance components of the disturbance process. A spatial counterpart of the Cochrane‐Orcutt transformation leads to a feasible generalized least squares procedure to estimate the regression parameters. Monte Carlo simulations show that our estimators perform well in terms of root mean square error compared to the maximum likelihood estimator. The approach is applied to English house price data for districts nested within counties.     

Complex Contagions and the Diffusion of Innovations: Evidence from a Small-N Study

The recent literature on “complex contagions” challenges Granovetter’s classic hypothesis on the strength of weak ties and argues that, when the actors’ choice requires reinforcement from several sources, it is the structure of strong ties that really matters to sustain rapid and wide diffusion. The paper contributes to this debate by reporting on a small-N study that relies on a unique combination of ethnographic data, social network analysis, and computational models. In particular, we investigate two rural populations of Indian and Kenyan potters who have to decide whether to adopt new, objectively more efficient and economically more attractive, technical/stylistic options. Qualitative field data show that religious sub-communities within the Indian and Kenyan populations exhibit markedly different diffusion rates and speed over the last thirty years. To account for these differences, we first analyze empirically observed kinship networks and advice networks, and, then, we recreate the actual aggregate diffusion curves through a series of empirically calibrated agent-based simulations. Combining the two methods, we show that, while single exposure through heterophilious weak ties were sufficient to initiate the diffusion process, large bridges made of strong ties can in fact lead to faster or slower diffusion depending on the type of signals circulating in the network. We conclude that, even in presence of “complex contagions,” dense local ties cannot be regarded as a sufficient condition for faster diffusion.     

MODELING RESIDENTIAL CHOICE*

ABSTRACT. This paper presents a new approach in the modeling of residential choices for simulation purpose. The originality of the approach resides in the way recent developments in stochastic choice models are combined with deterministic mathematical programming which allows to define an equilibration process for simulation. In that respect, ex ante probabilities of housing choice based on random utility maximization under perceived constraints are distinguished from ex post probabilities of choice that respect supply constraints. The proposed model is tested on the Montreal Metropolitan Region, and a few simulation results based on a scenario of population aging and decrease in household size are analyzed.     

ABORIGINAL SOCIAL INEQUALITY AND RECIPROCITY

This paper seeks to show that while the idea of reciprocity is fundamental in Australian Aboriginal societies, inequalities are also inherent in the kinship system itself. An attempt is then made to articulate these two aspects and to specify the form of social inequality which is characteristic of Australia. Cet article prétend montrer, d'une part, que l'idée de réciprocité est fondamentale dans les sociétés australiennes, d'autre part, que les inégalités le sont tout autant dans la mesure où elles sont insuites et fondeés dans la parenté elle-même. Il cherche aussi à montrer comment réciprocité et inégalité s'articulent entre elles. Enfin, it tente de spécifier la forme d'inégalité sociale caractéristique de l'Australie.     

Multi-method (TL and OSL), multi-material (quartz and flint) dating of the Mousterian site of Roc de Marsal (Dordogne,France): correlating Neanderthal occupations with the climatic variability of MIS 5–3

Roc de Marsal has yielded numerous remains of Mousterian occupations, including lithics, fauna and combustion features. It was made famous by the discovery of the skeleton of a Neanderthal child. Given the need to date the sequence, TL and OSL were applied on heated flints and quartz, and OSL on unheated quartz. Chronological results combined with palaeoenvironmental data – faunal remains and micromorphological features in the sediments from the cave, pollen proxies and faunal remains from the region – allowed us to place climate variations in southwest France on a numerical time scale. Denticulate Mousterian occupations were dated to the middle of MIS 4 (65–70 ka) and Quina layers either to the very end of MIS 4 or to MIS 3. Interestingly, a faunal pattern showing a mix of red deer, roe deer and reindeer was found to have occurred during MIS 4, which was shown to be consistent with data from other similar sites in southwest France.     

The significance of Ptolemy’s Almagest for its early readers

The paper explores the historical reasons why Ptolemy's Almagest was cultivated in Antiquity as a legitimate part of ancient culture. It tries to elucidate first the precise nature of Ptolemy's project in the Almagest, its relation to ethics as well as to the particular conception that Ptolemy had of mathematics. It then proposes an explanation for the fact that this treatise, both in Ptolemy's period and afterwards, was studied within the milieu of ancient astrologers.     

Strontium isotope ratios in fossil teeth from South Africa: assessing laser ablation MC-ICP-MS analysis and the extent of diagenesis

This study tests the precision and accuracy of laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) for measuring strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) in fossil teeth from Swartkrans and Sterkfontein in South Africa, and explores the extent of diagenesis in these specimens. Compared to solution MC-ICP-MS or thermal ionization mass spectrometry (TIMS) methods, LA-MC-ICP-MS can be faster and less expensive, but has lower precision and accuracy. We found that ⁸⁷Sr/⁸⁶Sr ratios in fossil rodent teeth measured by LA-MC-ICP-MS were offset from solution values by a mean of 0.0005 ± 0.0010 (2σ). Because of the very wide spread of biologically available ⁸⁷Sr/⁸⁶Sr ratios (∼0.710 to ∼0.790) in the region, LA-MC-ICP-MS is more than sufficient for assessing the geographic origins of the fossil rodents. The concentration of strontium in modern and fossil enamel from the area is statistically indistinguishable, as is the range of ⁸⁷Sr/⁸⁶Sr ratios in modern rodents and fossil rodents from Swartkrans. Thus, there is little evidence of diagenetic Sr in the fossil enamel. In contrast, the fossil dentine may contain up to ∼50% diagenetic strontium, although many dentine ⁸⁷Sr/⁸⁶Sr ratios are still far removed from the background cave value of 0.729. We propose that LA-MC-ICP-MS will also be of use for investigating the geographic origins of other, non-rodent fossil teeth from the Sterkfontein and Swartkrans collections, and may prove of similar utility at other suitable sites.     

The Teaching of Arabic in French Algeria and Contemporary France

This article examines the history of the teaching of Arabicin colonial Algeria as a means of clarifying the contemporarydebate on language policy in the French education system. Untilnow this history has only been explored in the limited contextof post-Independence Algeria and in a rather simplistic fashion,which suggests that the colonial authorities conducted a hostilecampaign against the Arab language. In fact, as will be seen,the situation was far more complex, with a much more sympatheticapproach being adopted than one might expect. However, therewere various forms of Arabic to take into account and attitudeswere in a constant state of flux throughout the colonial period.     

Satellite imagery and archaeology: the example of CORONA in the Altai Mountains

Satellite imagery, and specifically CORONA, is now of common use in archaeology. CORONA, as it produces two images of the same spot (afterward and forward), allows for stereoscopic view and is a perfect tool for the production of maps, especially in remote areas, where maps are not reliable of even absent.     

À propos du colloque « The Machine as Model and Metaphor » Max-Planck-Institut für Wissenschaftsgeschichte Berlin,novembre 2006

Sans résumé ? Lève la peau, dissèque: ici commencent les machines. Puis, tu te perds dans une substance inexplicable, étrangère à tout ce que tu sais et qui est pourtant l’essentielle. ? Paul Valéry, Tel quel, Cahier B 1910 Ses recherches portent sur l’épistémologie, l’histoire des sciences et l’histoire de la philosophie à l’age classique (xvi ^e-xvii ^e siècles). Elle a notamment dirigé avec Walter Roy Laird, Mechanics and Natural Philosophy before the Scientific Revolution (Dortrecht/Boston/Londres, Kluwer Academic Publishers, 2007), puis, en collaboration avec Massimo Bucciantini et Michele Camerota, Mechanics and Cosmology in the Medieval and Early Modern Period (Florence, Olschki, 2007).