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41.
Neil S. Davies Ivan J. Sansom Robert S. Nicoll Alex Ritchie 《Alcheringa: An Australasian Journal of Paleontology》2013,37(4):553-569
The Stairway Sandstone is a 30–560 m thick succession of Middle Ordovician siliciclastic sedimentary rocks within the Amadeus Basin of central Australia, deposited in the epeiric Larapintine Sea of northern peri-Gondwana. The Stairway Sandstone is significant as one of only two known Gondwanan successions to yield articulated arandaspid (pteraspidomorph agnathan) fish. Herein we use the ichnology of the Stairway Sandstone to reveal insights into the shallow marine habitat of these early vertebrates, and compare it with that of other known pteraspidomorph-bearing localities from across Gondwana. The Stairway Sandstone contains a diverse Ordovician ichnofauna including 22 ichnotaxa of Arenicolites, Arthrophycus, Asterosoma, Cruziana, Didymaulichnus, Diplichnites, Diplocraterion, ?Gordia, Lockeia, Monocraterion, Monomorphichnus, Phycodes, Planolites, Rusophycus, Skolithos and Uchirites. These ichnofauna provide a well-preserved example of a typical Ordovician epeiric sea assemblage, recording the diverse ethologies of tracemakers in a very shallow marine environment of flashy sediment accumulation and regularly shifting sandy substrates. New conodont data refine the age of the Stairway Sandstone to the early Darriwilian, with ichnostratigraphic implications for the Cruziana rugosa group and Arthrophycus alleghaniensis. 相似文献
42.
Alex Gibson Sheena Asthana† 《Transactions (Institute of British Geographers : 1965)》2000,25(3):303-319
Notwithstanding the recent change of government, UK educational policy continues to stress school performance tables, parental choice and competition – reflecting an acceptance by New Labour of Tory notions concerning the role that market mechanisms play in improving school performance. In view of the 1997 Education White Paper's insistence that the new government's goal was to 'overcome the spiral of disadvantage … passed from one generation to the next', this implies that the DfEE remains unimpressed by long-standing arguments concerning the socially-divisive consequences of market forces in education.
This paper seeks to add empirical weight to this debate. Arguing that recent analyses of aggregate levels of social stratification have masked polarization occurring at the local level, our analysis places schools in the context of the local markets within which they operate. This yields clear evidence that educational markets tend to exacerbate existing differences between schools in terms of both their performance and social status. 相似文献
This paper seeks to add empirical weight to this debate. Arguing that recent analyses of aggregate levels of social stratification have masked polarization occurring at the local level, our analysis places schools in the context of the local markets within which they operate. This yields clear evidence that educational markets tend to exacerbate existing differences between schools in terms of both their performance and social status. 相似文献
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Walter Crist Alex de Voogt Anne‐Elizabeth Dunn‐Vaturi 《Oxford Journal of Archaeology》2016,35(2):179-196
This re‐evaluation of existing data on board games from the Near Eastern Bronze Age demonstrates their function as social lubricants in cross‐cultural interaction. Board games are situated theoretically as liminoid practices, which lie outside the bounds of normative social behaviour and allow for interaction across social boundaries. Utilizing double‐sided game boards, with an indigenous game on one side and a newly introduced game on the other, the games of senet, mehen and twenty squares provide evidence for social interactions. Cypriots had adopted Egyptian mehen and senet by the third millennium BC, and indigenized the games. This lies in contrast to the game of twenty squares, which had a particular role among elites in the Late Bronze Age interaction sphere. This anthropological discussion of evidence relating to gaming seeks to inspire further research on the role of board games in society. 相似文献
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Radiocarbon dates are presented for distinctive types of British Late Neolithic pottery, identifying questions which cannot yet be resolved. 相似文献
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Alex Anas 《Journal of regional science》1988,28(4):511-530
ABSTRACT. Boyce et al. (1981, 1983) have proposed and implementd the use of observed entropy levels to estimate the travel-cost coefficient in mathematical programming models of network equilibrium which involve logit route-choice probabilities. This so-called “dispersion-constrained” model is shown to give severely biased and statistically inefficient underestimates. A natural counterpart, the entropy-maximizing model, is proposed here and overestimates the travel-cost coefficient with much lower bias and much higher statistical efficiency. Even though the two models are mathematically homeomorphic in some respects, they have vastly different statistical properties. It follows that the use of observed entropy levels is undesirable and should be avoided, since maximizing entropy provides an unambiguously superior alternative. 相似文献
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In this article, we study the U.S. Senate to understand how legislators' previous experiences in elected office influence their political behavior. We posit that, as a result of their experiences in office, former governors in the Senate are less partisan than their colleagues. We code the political jobs held by senators between 1983 and 2015 and analyze the effects of these careers on party loyalty in Senate floor votes. We find that gubernatorial service is associated with a 7–8% decrease in Party Unity. We test several hypotheses for the observed “governor effect” and find that, relative to their colleagues, former governors are supported by donor networks that are less ideologically extreme. We conclude that the unique experiences associated with serving as governor, along with the personalized nature of governors' electoral support coalitions, affect a senator's relationship with the party. Ultimately, our analysis illuminates how personal attributes, such as prior experience in elected office, can inform the study of legislative behavior. 相似文献
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ABSTRACT RELU is a dynamic general equilibrium model of a metropolitan economy and its land use, derived by unifying in a theoretically valid way, models developed by one of the authors [ Anas (1982) , Anas–Arnott (1991, 1997) , Anas–Kim (1996) , Anas–Xu (1999) ]. RELU equilibrates floor space, land and labor markets, and the market for the products of industries, treating development (construction and demolition), spatial interindustry linkages, commuting, and discretionary travel. Mode choices and equilibrium congestion on the highway network are treated by unifying RELU with the TRAN algorithm of stochastic user equilibrium [ Anas–Kim (1990) ]. The RELU‐TRAN algorithm's performance for a stationary state is demonstrated for a prototype consisting of 4‐building, 4‐industry, 4‐labor‐type, 15‐land‐use‐zone, 68‐link‐highway‐network version of the Chicago MSA. The algorithm solves 656 equations in a special block‐recursive convergent procedure by iterations nested within loops and loops within cycles. Runs show excellent and smooth convergence from different starting points, so that the number of loops within successive cycles continually decreases. The tests also imply a numerically ascertained unique stationary equilibrium solution of the unified model for the calibrated parameters. 相似文献