NETWORK LOADING VERSUS EQUILIBRIUM ESTIMATION OF THE STOCHASTIC ROUTE CHOICE MODEL MAXIMUM LIKELIHOOD AND LEAST SQUARES REVISITED*

Daganzo (1977, 1979), Daganzo and Sheffi (1977), Sheffi (1985), and Sheffi and Daganzo (1980) have used one assumption about traveler behavior in developing estimation techniques for the stochastic route-choice problem and another assumption in predicting flows on networks by using the same model. In estimation, they calculate the congested travel costs of the network links from observed flows on the network, and the network is loaded based on these costs. In prediction, they follow their stochastic user-equilibrium assumption by which travelers evaluate costs using the mean of the observed flows (or equilibrium flows). The travel-cost coefficient obtained from the loading method systematically overestimates the true travel-cost coefficient from which the observed flow data (which must be used in loading) is generated. The estimates of the same coefficient, obtained in this paper, by constraining the estimation results to conform to the equilibrium conditions are unbiased, and only marginally less efficient (have larger standard deviations). The average percentage error and inefficiency of the link flow predictions based on the loading method increases as the level of congestion on the network rises. In contrast, the average percentage error of link flow predictions based on the equilibrium estimation method declines and their efficiency remains very high as the level of congestion on the network rises.     

Zopilotes,Alacranes, y Hormigas (Vultures,Scorpions, and Ants): Animal Metaphors as Organizational Politics in a Nicaraguan Garbage Crisis

While scholars frequently frame conflicts over urban waste in terms of a politics of infrastructure, this article frames such conflicts in terms of a politics of organization. In 2008, self‐employed recyclers in and around Managua, Nicaragua blockaded local dumps in an effort to secure rights to scavenge for resellable material. Over the course of this “garbage crisis”, a material and semiotic entanglement of human labor organization with animal ecology became politically salient. At different points, recyclers were compared to ants (hormigas), vultures (zopilotes), and scorpions (alacranes). State officials, NGOs, and recyclers themselves used these animal metaphors to describe the organization of waste collection. Drawing on theories of value from political ecology and economic anthropology, as well as analysis of the deployment of these “organic” metaphors, we outline an “organizational politics” of urban waste.     

Late Middle Palaeolithic occupations in Ciemna Cave,southern Poland

Recent excavations in Ciemna Cave in the Pr?dnik valley near Ojców, southern Poland have brought to light new stratigraphic and techno-typological evidence concerning Late Middle Palaeolithic groups and their cultural affinities. In 2007, excavations began in the hitherto-unexplored main chamber of Ciemna Cave, with the goal of clarifying the results of previous work in other parts of the cave. During excavation the rocky floor of the cave was reached. About 1000 stone artifacts have been collected to date. Three cultural traditions have been documented: Mousterian, Taubachian, and Micoquian. Within the Micoquian tradition, three cultural levels were observed, which enriches the previous understanding of occupational phases at the site. These findings permit revision of the traditional terms “Pr?dnik industry” and “Pr?dnik technique.”     

The Current Status of the Kenya Capsian

East Africa is home to a rich array of stone-tool traditions that span human prehistory. It is unsurprising, therefore, that the region attracted pioneer prehistorians in the early twentieth century, including L. S. B. Leakey, E. J. Wayland and T. P. O’Brien, who created the first cultural framework for East African prehistory during the 1930s. Although aspects of this framework remain relevant today, others have become misunderstood relics of an old classification system that hinders current research. This is particularly evident in the classification of a Later Stone Age (LSA) culture – the Kenya (East African) Aurignacian, later known as Kenya (East African) Capsian. Although this cultural entity was redressed during the 1970s and 1980s and redefined as the Eburran industry, there is still mystique surrounding the current status of the Kenya Capsian, its original scope and definition, the relationship with the Eburran and its position within a modern understanding of the East African LSA. This is largely due to paradigmatic shifts in researcher attitudes, leading to the use of the Eburran as a false proxy. It is necessary now to completely remove the term Kenya Capsian as an indication of similarity among the different LSA technologies. However, there also needs to be less emphasis on the importance of the Eburran and recognition that it is just one example of a multitude of diverse localised LSA industries. This will open the way for future research into the LSA and facilitate our greater understanding of recent prehistory in East Africa.     

Theoretical change and therapeutic innovation in the treatment of syphilis in mid-nineteenth-century France

This article examines changes in the treatment of venereal disease in mid-nineteenth-century France in light of theoretical developments in the understanding of these diseases. It focuses on three theories of venereal disease: the orthodox theory of the "unity" of gonorrhea and syphilis; the physiological theory of Fran?ois Broussais, which essentially denied the actual existence of such a disease; and Philippe Ricord's new doctrine of venereal disease, a theory that is often credited with having established the distinction between syphilis and gonorrhea. The argument is that theoretical considerations played a major role in the evaluation of the relative merits of these theories and that any understanding of the appeal of Ricord's new doctrine must consider not only its pathological claims but its therapeutic implications as well. This was not, however, simply an instance of theory applied. These two aspects of Ricord's new doctrine, its pathology and its therapeutics, were inextricably bound up with one another, so that judgment of the one necessarily entailed judgment of the other. The argument is that therapeutic practice should not be seen simply as a downwind consequence of changes in the theoretical understanding of disease, but rather as an integral part of the process of change. These were the kinds of developments that led doctors to believe that French medicine was making very real progress at mid-century.     

WHY ARE URBAN TRAVEL TIMES SO STABLE?

Personal travel time in U.S. urban areas has been stable, clashing with the assertion that urban sprawl greatly lengthens travel. Average commute time rises by 7.7 percent with each cross‐sectional doubling of Metropolitan Statistical Area (MSA) jobs. Using the RELU‐TRAN structural computable general equilibrium model of the Chicago MSA, we simulate the equilibrium effects of a 24 percent population increase projected from 2000 to 2030 by the Chicago Metropolitan Agency for Planning. If no new road capacity is added, then congestion per mile increases. Although the urbanized land area increases by 19 percent, indicating sprawl, the vehicle miles traveled (VMT) per car‐trip decreases by 1.31 percent and the VMT per car‐trip to work decreases by 2.78 percent. Car travel time increases by only 6.25 percent and commuting time by only 4.54 percent, from 30.3 minutes in 2000 to 31.7 in 2030 or 3.4 seconds per year. We further explore the effects of new road capacity, gasoline prices, public transit speed, fuel economy gains, limits on suburban construction, and importantly, the cross‐elasticity of public transit use with respect to car times. The availability of public transportation, economizing on nonwork travel, and land use adjustments that increase job‐residence proximity keep times stable.     

Creative geographies of ceramic artists: knowledges and experiences of landscape,practices of art and skill

This paper argues for a conception of art as an embodied and creative material practice. It draws on research conducted with seven professional ceramic artists who deal with landscape in their work to explore their processes of art-making through interview and (filmed) observation. It demonstrates the distributed range of embodied and relational more-than-artistic practices which inform how landscape is encountered, known and ultimately represented. It argues that artists’ self-expression in art is based upon material, social and political knowledges which interweave in artists’ lives. By studying ceramicists’ making this paper demonstrates both the non-conscious skill and the conscious technical knowledge needed to make art. It shows chance to have a triple role in practices of making, as something to work alongside, to work against and to draw on as a creative resource. This paper both argues for and demonstrates the value of an approach to art-making that frames it as a complex of both conscious, socio-cultural, technical knowledges and non-conscious skills which together (in)form works of (ceramic) art.