Continuous‐Time Modeling with Spatial Dependence

(Spatial) panel data are routinely modeled in discrete time (DT). However, compelling arguments exist for continuous‐time (CT) modeling of (spatial) panel data. Particularly, most social processes evolve in CT, so that statistical analysis in DT is an oversimplification, gives an incomplete representation of reality, and may lead to misinterpretation of estimation results. The most compelling reason for a CT approach is that, in contrast to DT modeling, it allows adequate modeling of dynamic adjustment processes. This article introduces spatial dependence in a CT modeling framework. We propose a nonlinear structural equation model (SEM) with latent variables for estimation of the exact discrete model (EDM), which links CT model parameters to DT observations. The use of a SEM with latent variables enables a specification that accounts for measurement errors in the variables, leading to a reduction of attenuation bias (i.e., disattenuation). The SEM‐CT model with spatial dependence developed here is the first dynamic SEM with spatial dependence. A simple regional labor market model for Germany, comprising changes in unemployment and population as endogenous state variables, and changes in regional average wages and in the structure of the manufacturing sector as exogenous input variables, illustrates this spatial econometric SEM‐CT framework. El modelamiento de datos panel espaciales se realiza habitualmente utilizando una conceptualización del tiempo discreto (TD). Sin embargo, existen argumentos de peso para conceptualizar el tiempo de manera continua (TC). En concreto, la mayoría de procesos sociales se desarrolla en TC, por lo que el análisis estadístico en DT trae como consecuencia una simplificación excesiva de los procesos, da una representación incompleta de la realidad, y puede conducir a una interpretación errónea de los resultados de la estimación. La razón más convincente para el uso de un enfoque CT es que a diferencia de modelos DT, una conceptualización CT permite el modelado adecuado de los procesos de ajuste dinámico (dynamic adjustment). Este artículo incorpora la dependencia espacial en un marco de modelamiento con CT. Los autores proponen un modelo de ecuaciones estructurales no lineal (nonlinear structural equation model ‐SEM) con variables latentes para la estimación del modelo discreto exacto (exact discrete model‐EDM), que vincula los parámetros del modelo CT a las observaciones de DT. El uso de un SEM con variables latentes permite una especificación que da cuenta de los errores de medición en las variables, dando lugar a una reducción del sesgo de atenuación (es decir, “desatenuacion”). El modelo SEM‐CT con dependencia espacial desarrollado en el presente estudio es el primer SEM dinámico con dependencia espacial. Para ilustrar el marco conceptual SEM‐CT los autores presentan un modelo simple del mercado laboral regional de Alemania. El modelo está compuesto por los cambios en el desempleo y la población como variables endógenas de estado, y los cambios en los salarios regionales promedio y en la estructura del sector manufacturero como variables de entrada exógenas. （空间）面板数据通常基于离散时间（DT）进行建模。然而更令人信服的观点是基于连续时间（CT）进行（空间）面板数据建模。特别是多数社会过程均在连续时间中演化,基于离散时间的统计分析可能过度简化,使得对现实状况的表达不完备,并可能导致对估计结果的错误解释。相比于离散时间（DT）建模,连续时间（CT）建模最具说服力的原因在于在建模过程中允许足够多的动态调整。本文介绍了CT模型框架中的空间依赖性。把CT模型参数链接到DT观察值中,我们提出了用于估计精确离散模型（EDM）的包含潜变量的非线性结构方程模型（SEM）。包含潜在变量的SEM提供了变量测量误差的计算方案,使得衰减偏差（如反衰减性）减小。本文了提出的空间相关SEM‐CT模型是第一个动态空间相关的SEM模型,并以德国一个简单的区域劳动力市场模型为例,以失业和人口构成变化为内生状态变量,以区域平均工资和制造业结构部门变化为外生输入变量,阐述了该空间计量SEM‐ CT模型的框架。     

Metallic encounters in Cuba: The technology,exchange and meaning of metals before and after Columbus

Metals held important symbolic and political values for the indigenous communities of the Caribbean islands. However, metal objects are not abundant in indigenous archaeological sites, and their study has hitherto been very limited. This paper presents the results of the first analytical programme focused on metal artifacts recovered in a range of Taíno sites in Cuba, chronologically covering the periods before and after contact with Europeans. Our aims were: (a) to identify metallurgical traditions related to a diversity of cultural or learning backgrounds; (b) to investigate the origins of different metal artifacts found in Cuba, as a proxy to reconstruct patterns of exchange and interaction among indigenous communities and between these and Europeans; and (c) to approach the meaning and symbolism of different metals by considering their contexts of appropriation and use. The techniques employed included optical microscopy, SEM–EDS, pXRF and PIXE. The results allow a diachronic picture of the procurement, transformation, use and symbolism of metals in Cuba with broader implications for Caribbean archaeology. We reveal culture-specific Taíno choices in their interaction with materials and value systems from continental America and Europe. We also discuss the selective appropriation, recontextualization and meaning of different metals in the indigenous cultures.     

PERSISTENCE OF REGIONAL UNEMPLOYMENT: APPLICATION OF A SPATIAL FILTERING APPROACH TO LOCAL LABOR MARKETS IN GERMANY*

ABSTRACT The geographical distribution and persistence of regional/local unemployment rates in heterogeneous economies (such as Germany) have been, in recent years, the subject of various theoretical and empirical studies. Several researchers have shown an interest in analyzing the dynamic adjustment processes of unemployment and the average degree of dependence of the current unemployment rates or gross domestic product from the ones observed in the past. In this paper, we present a new econometric approach to the study of regional unemployment persistence, in order to account for spatial heterogeneity and/or spatial autocorrelation in both the levels and the dynamics of unemployment. First, we propose an econometric procedure suggesting the use of spatial filtering techniques as a substitute for fixed effects in a panel estimation framework. The spatial filter computed here is a proxy for spatially distributed region‐specific information (e.g., the endowment of natural resources, or the size of the “home market”) that is usually incorporated in the fixed effects coefficients. The advantages of our proposed procedure are that the spatial filter, by incorporating region‐specific information that generates spatial autocorrelation, frees up degrees of freedom, simultaneously corrects for time‐stable spatial autocorrelation in the residuals, and provides insights about the spatial patterns in regional adjustment processes. We present several experiments in order to investigate the spatial pattern of the heterogeneous autoregressive coefficients estimated for unemployment data for German NUTS‐3 regions. We find widely heterogeneous but generally high persistence in regional unemployment rates.     

Determinants of Market Extension in Knowledge-Intensive Business Services: Evidence from a Regional Innovation System

Several studies have emphasized the role of knowledge-intensive business services (KIBS) in fostering innovation in metropolitan areas and regional innovation systems. Such areas are capable of expressing a strong demand for KIBS and consequently stimulate the rise and growth of KIBS. Despite an abundance of literature on KIBS emphasizing the relevance of spatial proximity to customers, many KIBS develop relationships on a broader national or even international scale. No studies have focused explicitly on this apparent discrepancy as yet. The aim of this paper is therefore to fill this theoretical and empirical gap by explaining the firm-level factors relating to the market extension of KIBS within the framework of regional innovation systems. Our analysis is based on a quantitative study on more than 150 KIBS supplying design or communication services located in the Veneto region (north-eastern Italy), an area that can be described as a regional innovation system. Five variables were considered, that is, size, experience, service standardization, investments in network technologies and relational intensity. Our results confirm that three of these variables, but not service standardization and relational intensity, correlate positively with the market extension of KIBS. Policy implications are also discussed.     

Late antique glass from Salapia: Tracking production and trading networks

The investigation of 38 late antique vessels from the archaeological excavation of Salapia has been performed using EMPA and LA-ICP-MS. The collection was made using impure sands and mineral soda. Among coloured glass, most vessels were made of ‘fresh’ glass. The use of colouring agents is rare, and most decoloured glass is obtained by Mn addition. Sb-decolouration is limited to one cup, and two colourless vessels show both manganese and antimony. As for provenance, the prevalence of Egyptian-HIMT glass over the Levantine is evident. Among Levantine glass, Jalame glass is represented, whereas Apollonia glass is absent. Among Egyptian (and deemed Egyptian) glass, the prevalence of HIMT glass over the other types has been observed. The high attestation of fresh glass, most notable in the earlier centuries, suggests the importation of glass in the form of finished objects, especially luxury vessels.     

The enemy underground: geostrategic intelligence and the war in Algeria

During the Algerian war (1954–1962), beside the war events proper, another conflict took place: a diplomatic and technocratic battle for the possession of Saharan oil resources in the name of national energy security. Its main actors were France, Italy, the US, and Algerian independence fighters. In the case I analyse in this paper, I show that the three Western-block countries used their local knowledge of the subsurface given by the collaboration of the three elements of: (1) geoscientists, (2) their national oil companies, and (3) their respective diplomatic bodies, in order to carve out a prominent place for themselves in the exploitation of Saharan resources. Algerian nationalists also succeeded in benefiting from this knowledge. I argue that this struggle for natural resources in a post-independence scenario, and the corresponding role of the geosciences in it, significantly contributed to influence the final configuration of the postwar Algerian hydrocarbon sector.     

Railways and manufacturing productivity in Italy after unification

This paper contributes to the debate on the effects of transport infrastructure endowment on productivity by adding a historical perspective. This allows us to address the issue in a proving ground where the effects of the existing stock of infrastructure are negligible. At the time of unification, the Kingdom of Italy initiated a large infrastructure project to build railways. We find that railways had a positive effect on manufacturing productivity over the period 1871–1911. Railways also had strong spillover effects in neighboring provinces so that provinces that started with a higher endowment of railways benefited more than those who were newly endowed.     

Radiocarbon and U-series dating of the endemic deer Praemegaceros cazioti (Depéret) from “Grotta Juntu”, Sardinia

Radiocarbon and U-series methods (²³⁰Th/U and ²³¹Pa/²³⁵U) for absolute age determination have been applied to some fossil samples from Grotta Juntu, in North Eastern Sardinia (Italy). The remains belong to the endemic deer species Praemegaceros cazioti, which is here represented by an almost complete skeleton. The three dating methods lead to concordant ages of about 7500 years BP, indicating that the skeleton was maintained as closed system after burial. Taking into consideration these results, Praemegaceros cazioti from Grotta Juntu is now the youngest representative of this species in Sardinia.     

Regional Efficiency in the European Union

This paper examines existing disparities in technical efficiency levels across the European regions over the period 1986–2002. The results reveal that technical efficiency is not randomly distributed across space in the European setting. On the contrary, the different tests performed highlight the presence of positive spatial autocorrelation and spatial heterogeneity in the distribution under consideration. In fact, we have detected several regional clusters characterized by similar efficiency levels distinguishing them from the rest of the sample. Nevertheless, the estimates carried out show the existence of a process of regional convergence in terms of technical efficiency during the study period. Our findings also reveal that factors such as the regional stock of capital per worker or the patterns of productive specialization are relevant in explaining the changes in technical efficiency experienced by the European regions between 1986 and 2002.     

Rewriting the end of the Early Bronze Age in the United Arab Emirates through the anthropological and artefactual evaluation of two collective Umm an-Nar graves at Hili (eastern region of Abu Dhabi)

The Hili archaeological complex in Al Ain (U.A.E.) is important for its wealth of third-millennium BC Umm an-Nar burial and settlement sites. Two of the most significant burial sites are Tomb N at Hili and Tomb A Hili North. The latter is a classic circular Umm an-Nar monumental grave, while Hili N is a pit-grave, one of only two Umm an-Nar period pit-graves discovered so far in the U.A.E. Both of these tombs contained the remains of hundreds of individuals, in the case of Tomb A Hili North, more than 300, while around 600 people had been deposited in Hili N. Both population groups have been the subject of anthropological and artefactual analyses and a comparison of the findings help to shed light on the chronology of the end of the Umm an-Nar period.