Discriminant function analyses in archaeology: are classification rates too good to be true?

The use of discriminant function analyses (DFA) in archaeological and related research is on the increase, however many of the assumptions of this method receive a mixed treatment in the literature. Statisticians frequently use complex statistical models to investigate analytical parameters, but such idealised datasets may be hard to relate to “real-life” examples and the literature difficult to assess. Using two faunal datasets that are more typical of archaeological and related research, one comprised of size-corrected linear measurements of bovid humeri and another of 3D geometric morphometric (GMM) shape data of African monkey skulls, and two simulated datasets, we illustrate some of the most important but often ignored issues of DFA. We specifically show why it is paramount to address “over-fitting” by cross-validation when applying this method and how the probability of correctly classifying cases by chance can be properly and explicitly taken into account.     

High‐temperature magmatic fluid exsolved from magma at the Duobuza porphyry copper–gold deposit,Northern Tibet

The Duobuza porphyry copper–gold deposit (proven Cu resources of 2.7 Mt, 0.94% Cu and 13 t gold, 0.21 g t^?1 Au) is located at the northern margin of the Bangong‐Nujiang suture zone separating the Qiangtang and Lhasa Terranes. The major ore‐bearing porphyry consists of granodiorite. The alteration zone extends from silicification and potassic alteration close to the porphyry stock to moderate argillic alteration and propylitization further out. Phyllic alteration is not well developed. Sericite‐quartz veins only occur locally. High‐temperature, high‐salinity fluid inclusions were observed in quartz phenocrysts and various quartz veins. These fluid inclusions are characterized by sylvite dissolution between 180 and 360°C and halite dissolution between 240 and 540°C, followed by homogenization through vapor disappearance between 620 and 960°C. Daughter minerals were identified by SEM as chalcopyrite, halite, sylvite, rutile, K–feldspar, and Fe–Mn‐chloride. They indicate that the fluid is rich in ore‐forming elements and of high oxidation state. The fluid belongs to a complex hydrothermal system containing H₂O – NaCl – KCl ± FeCl₂ ± CaCl₂ ± MnCl₂. With decreasing homogenization temperature, the fluid salinity tends to increase from 34 to 82 wt% NaCl equiv., possibly suggesting a pressure or Cl/H₂O increase in the original magma. No coexisting vapor‐rich fluid inclusions with similar homogenization temperatures were found, so the brines are interpreted to have formed by direct exsolution from magma rather than trough boiling off of a low‐salinity vapor. Estimated minimum pressure of 160 MPa imply approximately 7‐km depth. This indicates that the deposit represents an orthomagmatic end member of the porphyry copper deposit continuum. Two key factors are proposed for the fluid evolution responsible for the large size of the gold‐rich porphyry copper deposit of Duobuza: (i) ore‐forming fluids separated early from the magma, and (ii) the hydrothermal fluid system was of magmatic origin and highly oxidized.     

Perceptual images of Conimbriga using High Dynamic Range

It is widely recognized that new technologies can play an important role in the interpretation of our cultural heritage legacy. This has become a powerful tool providing a better understanding of our past, and thereby, allowing us to attain a glimpse of the environments in which our ancestors lived. In this domain, the way we see such reconstructed environments is particularly important in order to establish an accurate interpretation of that historical setting. However, the desired visual accuracy in the representation of any archaeological scenario is strictly related to the technology used to visualize it. High Dynamic Range (HDR) technology encompasses the capacity to produce visual results similar to the visual acuity of the human eye, particularly in extreme lighting conditions, such as bright light or dim environments.     

Geospatial modeling of pedestrian transportation networks: a case study from precolumbian Oaxaca,Mexico

Using accumulated cost surfaces and various pathfinding techniques within Geographic Information Systems (GIS) software, archaeologists and other spatial scientists have developed increasingly sophisticated models of human movement. Despite their utility, these approaches can be limited because standard GIS software cannot model movement (1) from many origins to many destinations or (2) without specific origins and destinations. Absent these capabilities, it is particularly difficult to model networks of movement over a given tract of land if you are interested in obtaining a more general sense of movement dynamics, not specific site-to-site patterns. In this paper, we present an innovative way of modeling past movement that generates both natural-looking networks and also indicates the degree of traffic that may have existed on any particular segment of those networks. The “From Everywhere to Everywhere” (FETE) model generates networks based on topography and landcover without requiring that origin and destination points be supplied in advance. We apply the FETE model to a case from the southern Mexican state of Oaxaca, a region that has extensive archaeological and ethnohistoric data sets that serve as a test of the efficacy of our technique. A comparison of the FETE output with known late precolumbian and early colonial movement corridors indicates that the method is effective and should be useful for modeling networks in other areas.     

How reliable are our published archaeometric analyses? Effects of analytical techniques through time on the elemental analysis of obsidians

To assess the analytical accuracies and precisions of archaeometric elemental analyses by different techniques, a relatively homogeneous material such as obsidian must be studied. An assessment of published elemental concentration data from two Anatolian obsidian sources shows that while in most cases analytical accuracy is as high as is commonly expected, in some cases it is not. It also shows that the dispersions of elemental concentration data (indicators of analytical precisions) coming from modern analytical procedures are akin to the estimated homogeneity of the obsidian. Based on this latter observation, if one has element dispersion data from a single analytical technique, with a single source of obsidian as a control, data sets that contain multiple, but similar sources of obsidian may be differentiated.     

宋代以“重禄法”治吏惩赃政策评析

宋代熙宁年间,着力通过市易法、募役法等解决国家的财政收入问题,进而在国家行政体系的改革中推行增加吏禄、以重法治赃的"重禄法"(亦称"仓法",因首先推行自仓吏)。而市易法的收入是"重禄"的直接经济来源。实行"重禄法"以治吏惩贪,一定程度上遏制了吏的卖法弄权。由于熙宁改革的破产,重禄法难以广泛推行,并在元祐初年被名义上废止,但其以"重禄人"的形式至少推延至南宋绍兴年间;吏之有禄成为行政惯例,延续到南宋。重典治吏的思想则贯穿于宋王朝的始终。     

《陕西行都司志》存佚考

包节所撰《陕西行都司志》是明代唯一的一部行都司志。《包侍御集》卷5收有《甘肃志六序》,此《甘肃志》即《陕西行都司志》。该志《四库全书总目》收入"史部地理类存目"中,后世诸家目录即不见载,《陇右方志录》断定已佚,《四库全书存目丛书》也没有收录。但其资料被大量保存在清顺治十四年(1657年)重刊的《西镇志》、《凉镇志》、《甘镇志》、《肃镇志》和乾隆《甘肃通志》等地方志及顾炎武《肇域志》、《天下郡国利病书》等典籍中,其他如《禹贡锥指》、《水经注疏》等地理学著作也有引用。《古今图书集成.方舆汇编.职方典》之《陕西行都司部汇考》即由《陕西行都司志》删削篡改而成。该志有重要的史料价值,我们期待着辑本的成书出版。     

瓷器热释光高温峰测年的初步研究

对陕西耀州窑4个古瓷器碎片的热释光高温峰测量的结果表明,瓷器样品具有天然热释光信号,而且,其信号增长呈良好的线性,高温峰可以用于瓷器的年龄测定和真假鉴定之中,瓷器热释光高温峰技术有望成为热释光测定瓷器年龄的一个方法。     

The Silverton Field Experience: a model geography course for achieving high-impact educational practices (HEPs)

High-Impact Educational Practices (HEPs) are a set of specific teaching and learning approaches proven effective in university education. This paper focuses on the benefits derived from utilizing three particular HEPs (inquiry-based collaborative activities, undergraduate research, and experiential learning) while teaching a snow and ice field course titled “Silverton Field Experience.” Student evaluations and instructor feedback reinforce the notion that HEPs encourage deep learning. Deep learning is manifest through increased enthusiasm and participation as well as learning in ways that are meaningful, creative, and stimulating. In terms of pedagogy in geography, these HEPs also create an expanded sense of place and a new way to encourage spatial thinking. The HEPs outlined here are replicable in different geography sub-disciplines and among different settings in higher education and prove exciting to an audience of pedagogic researchers and teacher-practitioners in geographical education.     

Judging government economic performance

ABSTRACT

The macroeconomic theory of judging contends that when justices on courts of last resort consider cases involving their governments and economic issues their voting behaviour will be affected by the state of the economy. Using decisions from the High Court of Australia from 1970 through 2018, the findings suggest that both economic conditions, particularly inflation and the GDP growth rate, and the partisan identity of the Commonwealth government affect the Commonwealth’s probability of winning economic cases. The High Court’s behaviour is consistent with an institution that is part of the national policymaking system and is responsive to the state of the economy.