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Fluid inclusions of the H2O‐NaCl‐CaCl2 system are notorious for their metastable behavior during cooling and heating processes, which can render microthermometric measurement impossible or difficult and interpretation of the results ambiguous. This study addresses these problems through detailed microscopic examination of synthetic solutions during cooling and warming runs, development of methods to enhance nucleation of hydrates, and comparison of microthermometric results with different degrees of metastability with values predicted for stable conditions. Synthetic H2O‐NaCl‐CaCl2 solutions with different NaCl/(NaCl + CaCl2) ratios were prepared and loaded in fused silica capillaries and glass‐sandwiched films for microthermometric studies; pure solutions were used with the capillaries to simulate fluid inclusions, whereas alumina powder was added in the solutions to facilitate ice and hydrate crystallization in the sandwiched samples. The phase changes observed and the microthermometric data obtained in this study have led to the following conclusions that have important implications for fluid inclusion studies: (i) most H2O‐NaCl‐CaCl2 inclusions that appear to be completely frozen in the first cooling run to ?185°C actually contain large amounts of residual solution, as also reported in some previous studies; (ii) inability of H2O‐NaCl‐CaCl2 inclusions to freeze completely may be related to their composition (low NaCl/(NaCl + CaCl2) ratios) and lack of solid particles; (iii) crystallization of hydrates, which is important for cryogenic Raman spectroscopic studies of fluid inclusion composition, can be greatly enhanced by finding an optimum combination of cooling and warming rates and temperatures; and (iv) even if an inclusion is not completely frozen, the melting temperatures of hydrohalite and ice are still valid for estimating the fluid composition. 相似文献
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Andrew Ayres Alexander Degolia Matthew Fienup Yunyeol Kim Jade Sainz Laura Urbisci Daniel Viana Graham Wesolowski Andrew J. Plantinga Christina Tague 《Geography Compass》2016,10(2):67-86
In western North America, wildfire is a critical component of many ecosystems and a natural hazard that can result in catastrophic losses of human lives and property. Billions of dollars are spent suppressing wildfires each year. In the past decades, academic research has made substantial contributions to the understanding of fire and its interaction with climate and land management. Most reviews of the academic literature, however, are centered in either natural or social science. We offer an integrated cross‐disciplinary guide to state‐of‐the art fire science and use this review to identify research gaps. We focus on the modern era and understanding fire in the context of a changing climate in western North America. We find that studies combining social and natural science perspectives remain limited and that interactions among coupled system components are poorly understood. For example, while natural science studies have identified how fuel treatments alter fire regimes, few social science studies examine how decisions are made about fuel treatments and how these decisions respond to changes in fire regimes. A key challenge is to better quantify the effects of actual fire management policies in a way that accounts for the complexity of coupled natural and natural–human system interactions. 相似文献
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Daniel Eddisford 《Arabian Archaeology and Epigraphy》2022,33(1):23-48
Imported ceramics from Early Bronze Age contexts in southeast Arabia illustrate a complex multidirectional network of material and social interactions at this time. Significant socioeconomic changes that occurred in the Hafit (3200–2800 B.C.) and Umm an-Nar (2800–2000 B.C.) periods have been linked to external demand for copper, which is argued to have stimulated a change in subsistence patterns. Similarly, disruption to long-distance exchange networks by external factors has been cited as driving change at the end of the Umm an-Nar period. Archaeological evidence from the region suggests a shift in the direction of exchange from Mesopotamia to the Indus occurred around the middle of the third millennium B.C. However, a recent analysis of Mesopotamian historical sources has highlighted the scale of state-organised textile production for export to the lower Gulf in the later third millennium B.C. The site of Kalba 4 has a stratified sequence of occupation deposits dating from the Umm an-Nar and Iron Age (1300–300 B.C.). In this study, a typological analysis of imported ceramics is used to locate the Kalba in the chronological framework of the region and discuss the changing networks of long-distance exchange that were operating. The imported pottery at Kalba 4 indicates that the inhabitants of the site were exchanging goods with a range of polities, including southern Mesopotamia, the Indus Valley (Meluhha), southeast Iran (Marhashi) and Bahrain (Dilmun). A significant quantity of Late Akkadian ceramics at the site suggests it became an important location for Mesopotamian trade at this time. 相似文献
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Aura Korppi‐Tommola 《Scandinavian journal of history》2013,38(1-2):181-191
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Nancy Scheper‐Hughes 《Anthropology today》2015,31(4):26-27
This narrative deals with the author's experiences while attending a human trafficking panel at the Pontifical Academy of Social Sciences (PASS) in the Casina Pio IV, Vatican City, 7–21 April 2015. 相似文献