The Location Choice of Employment‐based Immigrants among U.S. Metro Areas*

Abstract. This paper examines the initial location choice of legal employment‐based immigrants to the United States using Immigration and Naturalization Service data on individual immigrants, as well as economic, demographic, and social data to characterize the 298 metropolitan areas we define as the universal choice set. Focusing on interactions between place characteristics and immigrant characteristics, we provide multinomial logit model estimates for the location choices of about 38,000 employment‐based immigrants to the United States in 1995, focusing on the top 10 source countries. We find that, as groups, immigrants from nearly all countries are attracted to large cities with superior climates, and to cities with relatively well‐educated adults and high wages. We also find evidence that employment‐based immigrants tend to choose cities where there are relatively few immigrants of nationalities other than their own. However, when we introduce interaction terms to account for the sociodemographic characteristics of the individual immigrants, we find that the estimated effects of location destination factors can reverse as one takes account of the age, gender, marital status, and previous occupation of the immigrants.     

Common ware production at Thamusida: dating and characterisation of Roman and Islamic pottery

Twenty-one samples of likely Roman, likely Islamic and unknown common ware from the archaeological site of Thamusida (Rabat, Morocco) were analysed in order to anchor selected types of pottery to a limited time span and, possibly, to a production area and technology. Analytical techniques were thermoluminescence, optical microscopy, scanning electron microscopy and X-ray fluorescence. The results arising from this research are definitely useful for the study of the site of Thamusida as well as for all researchers involved in archaeological and archaeometrical research in Morocco. Chronologies proposed on a typological base have been denied twice: a likely Islamic cup dates back to the second century a.d.; vice versa, a stewpot, framed into the Roman period, resulted to be an eighth century a.d. production. Moreover, the identification of an eighteenth century ceramic production is of outstanding importance, as it characterises a completely unknown production. Regarding the production area, four samples of both Roman and Islamic periods have been recognised as local productions of Thamusida.     

Technology Transfer at the Periphery of the Mycenaean World: The Cases of Mycenaean Pottery Found in Central Macedonia (Greece) and the Plain of Sybaris (Italy)*

The study of technology transfer in pottery production to the periphery of the Mycenaean world has been addressed by considering two different areas, southern Italy and central Macedonia. Technological features such as ceramic paste, decoration and firing have been determined for different ceramic groups established according to provenance criteria. The studies of technology and provenance have been performed following an archaeometric approach, using neutron activation analysis, petrographic analysis, X‐ray diffraction and scanning electron microscopy. The results have revealed the existence of two different models. On the one hand, southern Italy seems to exhibit a more organized pottery production, which follows a Mycenaean‐like technology, while in central Macedonia production is probably more varied, being based in part on the technology of the local tradition.     

THE PETROGRAPHY AND CHEMISTRY OF THIN‐WALLED WARE FROM AN HELLENISTIC– ROMAN SITE AT SEGESTA (SICILY)*

Samples of Roman thin‐walled ware from Segesta (northwestern Sicily), dating back to the early Imperial period, were studied by optical microscopy (OM) and Neutron Activation Analysis (NAA). Up to now, this class of Roman fine tableware has only occasionally been evaluated archaeometrically. Nevertheless, numerous production centres are believed to have been simultaneously active in the western Mediterranean area. Petrographic and chemical data seem to be in agreement with the archaeological hypothesis of local manufacture in Segesta for most of the analysed samples, through a comparison with kiln wasters and local raw materials. The effectiveness of thin‐section petrography for determining the provenance of such a tiny tempered class of pottery and the integrated use of two different grouping procedures (petrography and chemistry) were also tested.     

Infiltration of basinal fluids into high-grade basement, South Norway: sources and behaviour of waters and brines

Quartz veins hosted by the high‐grade crystalline rocks of the Modum complex, Southern Norway, formed when basinal fluids from an overlying Palaeozoic foreland basin infiltrated the basement at temperatures of c. 220°C (higher in the southernmost part of the area). This infiltration resulted in the formation of veins containing both two‐phase and halite‐bearing aqueous fluid inclusions, sometimes with bitumen and hydrocarbon inclusions. Microthermometric results demonstrate a very wide range of salinities of aqueous fluids preserved in these veins, ranging from c. 0 to 40 wt% NaCl equivalent. The range in homogenization temperatures is also very large (99–322°C for the entire dataset) and shows little or no correlation with salinity. A combination of aqueous fluid microthermometry, halogen geochemistry and oxygen isotope studies suggest that fluids from a range of separate aquifers were responsible for the quartz growth, but all have chemistries comparable to sedimentary formation waters. The bulk of the quartz grew from relatively low δ¹⁸O fluids derived directly from the basin or equilibrated in the upper part of the basement (T < 200°C). Nevertheless, some fluids acquired higher salinities due to deep wall‐rock hydration reactions leading to salt saturation at high temperatures (>300°C). The range in fluid inclusion homogenization temperatures and densities, combined with estimates of the ambient temperature of the basement rocks suggests that at different times veins acted as conduits for influx of both hotter and colder fluids, as well as experiencing fluctuations in fluid pressure. This is interpreted to reflect episodic flow linked to seismicity, with hotter dry basement rocks acting as a sink for cooler fluids from the overlying basin, while detailed flow paths reflected local effects of opening and closing of individual fractures as well as reaction with wall rocks. Thermal considerations suggest that the duration of some flow events was very short, possibly in the order of days. As a result of the complex pattern of fracturing and flow in the Modum basement, it was possible for shallow fluids to penetrate basement rocks at significantly higher temperatures, and this demonstrates the potential for hydrolytic weakening of continental crust by sedimentary fluids.     

Chemical tracers of Lusitanian amphorae kilns from the Tagus estuary (Portugal)

In this paper, the characterization of Roman amphorae from the Porto dos Cacos (PC) and Quinta do Rouxinol (QR) workshops, in the Tagus estuary, dating to a period between the 1st and 5th century AD was carried out on the basis of instrumental neutron activation analysis data on 260 amphorae fragments, together with mineralogical compositional studies obtained by X-ray diffraction.     

Investigation of palaeodiet in the North Caucasus (South Russia) Bronze Age using stable isotope analysis and AMS dating of human and animal bones

This paper addresses the question of human palaeodietary adaptation in the Eneolithic and Early Bronze Age periods of the North Caucasus (South Russia) using stable isotope analysis. One of the key questions is the presence of fish in the diet. AMS radiocarbon dating of archaeological bone collagen has also been carried out to investigate potential radiocarbon reservoir effects in human skeletal material as a result of an aquatic diet. A fish component has previously been suggested in the diet of Iron Age and Bronze Age humans across Eurasia by isotopic research and radiocarbon dating of contemporaneous human and animal bones. In the North Caucasus however, isotopic data is scant. This study presents a new set of stable isotopic data from several Early Bronze Age sites, mainly belonging to the Maikop culture of the North Caucasus. The results show that the diversity in climate and environment across the northern Caucasus may be a causal factor for the patterns observed in the stable isotope values of terrestrial herbivores. This affects the isotopic values of the humans consuming them. The differences in δ¹⁵N and δ¹³C ranges of both humans and fauna were found to correlate strongly with geography and climate; the most enriched isotopic values are found in the dry steppe areas to the north. Overall, a relatively high enrichment in δ¹⁵N values of humans compared to local terrestrial herbivores and carnivores was observed. This indicates that aquatic resources were probably part of the Bronze Age diet in the region although the extent of this needs further investigation. The dramatic effect of environmental factors on isotopic values in the Early Bronze Age of the North Caucasus illustrates how confident conclusions cannot be drawn on the basis of a small number of samples from widely differing regions and time periods. Radiocarbon dating can provide a useful tool for identifying dietary derived reservoir ages in humans, potentially caused by a fish diet. With two possible exceptions, the nine human–animal bone pair dated as part of this study showed no consistent indication for a consistent reservoir effect.     

3D numerical modeling of hydrothermal processes during the lifetime of a deep geothermal reservoir

Understanding hydrothermal processes during production is critical to optimal geothermal reservoir management and sustainable utilization. This study addresses the hydrothermal (HT) processes in a geothermal research doublet consisting of the injection well E GrSk3/90 and production well Gt GrSk4/05 at the deep geothermal reservoir of Groß Schönebeck (north of Berlin, Germany) during geothermal power production. The reservoir is located between ?4050 to ?4250 m depth in the Lower Permian of the Northeast German Basin. Operational activities such as hydraulic stimulation, production (T = 150°C; Q = ?75 m³ h^?1; C = 265 g l^?1) and injection (T = 70°C; Q = 75 m³ h^?1; C = 265 g l^?1) change the HT conditions of the geothermal reservoir. The most significant changes affect temperature, mass concentration and pore pressure. These changes influence fluid density and viscosity as well as rock properties such as porosity, permeability, thermal conductivity and heat capacity. In addition, the geometry and hydraulic properties of hydraulically induced fractures vary during the lifetime of the reservoir. A three‐dimensional reservoir model was developed based on a structural geological model to simulate and understand the complex interaction of such processes. This model includes a full HT coupling of various petrophysical parameters. Specifically, temperature‐dependent thermal conductivity and heat capacity as well as the pressure‐, temperature‐ and mass concentration‐dependent fluid density and viscosity are considered. These parameters were determined by laboratory and field experiments. The effective pressure dependence of matrix permeability is less than 2.3% at our reservoir conditions and therefore can be neglected. The results of a three‐dimensional thermohaline finite‐element simulation of the life cycle performance of this geothermal well doublet indicate the beginning of thermal breakthrough after 3.6 years of utilization. This result is crucial for optimizing reservoir management. Geofluids (2010) 10 , 406–421