A Framework for Exploring Urban Retail Discontinuities. 探索城市零售业不连续性的框架

A key area in the analysis of urban structural evolution is identifying discontinuities. Effective analysis could improve long‐term forecasting and provide a better understanding of how to steer an urban system toward a desirable future state. We use a simple aggregate retail model to demonstrate an algorithm for identifying discontinuities in model parameter space. Explorations of retailing in both Greater London and South Yorkshire in the United Kingdom illustrate how understanding a system's potential for discontinuity can provide insights for both policy makers and retail businesses. The Harris and Wilson model, described in the section so‐named, is used as a simple archetype to illustrate the new framework. This model can be developed in a straightforward way to incorporate further refinement. In “ Executing the model and visualizing the results ,” we describe a single model run and in “ Investigating discontinuities ,” we explain our framework for detecting and analyzing discontinuities. “ Identifying discontinuities in the London retail system ” shows the results of applying this methodology to the Greater London retail system, and in “ Practical applications ,” we explore the policy applications for this technique as related to the decline of town centers in the South Yorkshire retail system. Some concluding comments are offered in “ Conclusions .”     

Unsightly urban menaces and the rescaling of residential segregation in the United States

In this article, the author uses a slum clearance project in Lexington, Kentucky, as a lens through which to examine the spatial dynamics of racial residential segregation during the first half of the twentieth century. At the time, urban migration and upward socioeconomic mobility on the part of African Americans destabilized extant residential segregation patterns. Amid this instability, various spatial practices were employed in the interest of maintaining white social and economic supremacy. The author argues that such practices were indicative of a thoroughgoing reinvention of urban socio-spatial order that in turn precipitated the vastly expanded scale of residential segregation still found in U.S. cities today. Evidence of this reinvented ordering of urban space lies in the rendering of some long-standing African American neighborhoods as “out of place” within it and the use of slum clearance to remove the “menace” such neighborhoods posed to it.     

TIPPING AND RESIDENTIAL SEGREGATION: A UNIFIED SCHELLING MODEL*

ABSTRACT This paper presents a Schelling‐type checkerboard model of residential segregation formulated as a spatial game. It shows that although every agent prefers to live in a mixed‐race neighborhood, complete segregation is observed almost all of the time. A concept of tipping is rigorously defined, which is crucial for understanding the dynamics of segregation. Complete segregation emerges and persists in the checkerboard model precisely because tipping is less likely to occur to such residential patterns. Agent‐based simulations are used to illustrate how an integrated residential area is tipped into complete segregation and why this process is irreversible. This model incorporates insights from Schelling's two classical models of segregation (the checkerboard model and the neighborhood tipping model) and puts them on a rigorous footing. It helps us better understand the persistence of residential segregation in urban America.     

Determinants of Variation in Population–Employment Interaction Findings: A Quasi‐Experimental Meta‐Analysis. 人口‐就业相互作用的决定因素研究：一种准实验元分析法

This article reports about a metaregression analysis of empirical results generated using data for the northern Netherlands (1988–2002) in order to investigate the ambiguity in results in the population–employment interaction literature. Specifically, the analysis deals with the issue whether “jobs follow people” or “people follow jobs.” The article starts with introducing the basics of quasi‐experimental meta‐analysis and with identifying some advantages of using quasi‐experimental meta‐analysis as compared with the standard meta‐analysis approach. Two subsequent sections document the selection of the population–employment interaction model and salient characteristics of the data set as well as the setup of the primary analyses. A total of 4,050 quasi‐experimental empirical results for the jobs–people direction of causality are generated using different specifications and estimators for a spatial econometric interaction model. The subsequent metaregression analysis reveals that the empirical results are largely shaped by the spatial, temporal, and employment characteristics of the data sampling. The results also appear much more sensitive to different measurements of the model's key variables when compared with alternative specifications of the spatial weights matrix. The main determinant driving empirical results about jobs–people causality are differences in model specification and estimation, as revealed by an inherent bias in parameter estimates and misguided inferences for some of the commonly used specifications. Finally, suggestions for future research are identified.     

The Impact of Neutral and Nonneutral Productivity Growth on Creative Capital in a Trading Regional Economy. 区域经济贸易中中性和非中性生产力增长对创新资本的影响

We analyze a two‐sector model of a trading creative regional economy (TCRE) of the sort studied by Florida. Our analysis focuses on two cases. The first case concerns the impact of faster neutral, whereas the second case concerns the impact of faster nonneutral, productivity growth in the tradable sector on the employment of creative people in each of a TCRE's two sectors. In both cases, the sign of the percentage change in the steady‐state use of creative capital in the nontradable sector is ambiguous. In other words, the potential departure of creative people from the tradable to the nontradable sector does not depend upon whether the faster productivity growth being studied is neutral or nonneutral. In addition, because the effects of faster productivity growth in the tradable sector are not necessarily innocuous, a potential role exists for activist policy designed to countermand the possibly negative effects of faster productivity growth on either the tradable or the nontradable sector. This finding of possible “uneven development” is consistent with Florida's view that TCREs can give rise to externalities such as uneven regional development.     

Gibrat Revisited: An Urban Growth Model Incorporating Spatial Interaction and Innovation Cycles. 再评吉尔布瑞特：顾及空间相互作用和创新周期的城市增长模型

We designed a geographical model for simulating the distribution of urban growth in systems of cities. The model incorporates the hierarchical and spatial diffusion of innovation cycles through gravitational interactions within a set of cities. Using theoretical simulations, we demonstrate that this model is able to reproduce the observed properties of urban systems for the log‐normal distribution of city sizes as well as the observed distribution of growth rates. Our experimentation was performed on a large harmonized historical database that includes a few hundred French urban agglomerations between 1831 and 1999 (Pumain‐INED database). Both spatial interaction and innovation cycles are necessary ingredients to explain the evolution of urban hierarchies. We suggest that Gibrat's generic stochastic growth model based on independent entities should be replaced by a more relevant model of spatially and temporally interdependent geographical entities.     

A Geostatistical Linear Regression Model for Small Area Data. 一种适用于小区域数据的地统计线性回归模型

We present a new linear regression model for use with aggregated, small area data that are spatially autocorrelated. Because these data are aggregates of individual‐level data, we choose to model the spatial autocorrelation using a geostatistical model specified at the scale of the individual. The autocovariance of observed small area data is determined via the natural aggregation over the population. Unlike lattice‐based autoregressive approaches, the geostatistical approach is invariant to the scale of data aggregation. We establish that this geostatistical approach also is a valid autoregressive model; thus, we call this approach the geostatistical autoregressive (GAR) model. An asymptotically consistent and efficient maximum likelihood estimator is derived for the GAR model. Finite sample evidence from simulation experiments demonstrates the relative efficiency properties of the GAR model. Furthermore, while aggregation results in less efficient estimates than disaggregated data, the GAR model provides the most efficient estimates from the data that are available. These results suggest that the GAR model should be considered as part of a spatial analyst's toolbox when aggregated, small area data are analyzed. More important, we believe that the GAR model's attention to the individual‐level scale allows for a more flexible and theory‐informed specification than the existing autoregressive approaches based on an area‐level spatial weights matrix. Because many spatial process models, both in geography and in other disciplines, are specified at the individual level, we hope that the GAR covariance specification will provide a vehicle for a better informed and more interdisciplinary use of spatial regression models with area‐aggregated data.     

5. IMPERIAL SPACES IN PEKKA HÄMÄLÄINEN'S THE COMANCHE EMPIRE

This review focuses on Pekka Hämäläinen's characterization and analysis of the Comanche empire as a spatial category in The Comanche Empire and discusses how this work relates to broader discussions about space and power in borderlands and imperial histories. Although empires have long been central actors in borderlands histories, “empire” has not necessarily been a category of spatial organization and analysis and certainly not one used to describe spaces controlled by Native peoples. By contrast, while Hämäläinen emphasizes the imperial characteristics of the economic, political, and cultural dimensions of Comanche history (as other contributors to this forum discuss), he also uses “empire” to characterize Comanche dominance spatially. Hämäläinen helps us to rethink the spatial dynamics that both shaped and were produced by the encounters between Comanches and Spaniards, French, Mexicans, Americans, and other Native peoples in the Great Plains during the eighteenth and nineteenth centuries. By analyzing how Comanches came to control vast stretches of the southern plains, The Comanche Empire challenges our assumptions about how Native polities and imperial powers (and groups like the Comanches that Hämäläinen argues were both) thought about territorial claims and how they employed more nuanced spatial strategies to assert their authority, extend their cultural influence, and control trade and resources.     

“UNABLE TO RESIST”: ON THE “POSSIBILITY” OF “IMPOSSIBILITY” AND CHRISTOPHE BOUTON'S TIME AND FREEDOM

This essay reflects critically on Martin Heidegger's remarks about authenticity and death with the aid of Christophe Bouton's Temps et liberté (2002), translated by Christopher Macann as Time and Freedom (2014). It first raises general questions concerning the possible thematic relationship between human endeavoring (action) and the experiences of finitude and freedom. Heidegger's Being and Time is particularly useful for exploring this relationship, but certain problems emerge when using this text for accessing the essay's themes. To wit: there are good reasons for mistrusting readings of Being and Time as a “practical” guide for grounding action. Against the practical reading, the essay wishes to reclaim the ontological‐existential significance of Heidegger's text. Although Bouton's treatment of Being and Time excludes its ontological dimensions and is entirely practical, even to the point of disregarding certain theoretical risks inherent in this approach, Bouton's study is indispensable for situating Being and Time in a historical‐intellectual context, whereby the experiences of freedom and time are understood within certain metaphysical presuppositions rendering them difficult to establish together on reliable grounds. Following Bouton's lead, the essay shows that the hermeneutic differences between practical and ontological readings of Being and Time can be explored through reflections on what Heidegger might have meant by the term “Möglichkeit” (“possibility”), from which Bouton infers “freedom.” It is alleged that Bouton does not fully consider all of Heidegger's assertions regarding Möglichkeit, most problematically the claim that the human being's most essential “possibility” is its “impossibility,” that is to say, its death.     

A Wavelet‐Based Extension of Generalized Linear Models to Remove the Effect of Spatial Autocorrelation. 基于小波扩展广义线性模型消除空间自相关的影响

Biogeographical studies are often based on a statistical analysis of data sampled in a spatial context. However, in many cases standard analyses such as regression models violate the assumption of independently and identically distributed errors. In this article, we show that the theory of wavelets provides a method to remove autocorrelation in generalized linear models (GLMs). Autocorrelation can be described by smooth wavelet coefficients at small scales. Therefore, data can be decomposed into uncorrelated and correlated parts. Using an appropriate linear transformation, we are able to extend GLMs to autocorrelated data. We illustrate our new method, called the wavelet‐revised model (WRM), by applying it to multiple regression with response variables conforming to various distributions. Results are presented for simulated data and real biogeographical data (species counts of the plant genus Utricularia [bladderworts] in grid cells throughout Germany). The results of our WRM are compared with those of GLMs and models based on generalized estimating equations. We recommend WRMs, especially as a method that allows for spatial nonstationarity. The technique developed for lattice data is applicable without any prior knowledge of the real autocorrelation structure.     

Neoliberalism and the Aestheticization of New Middle‐Class Landscapes

Abstract: If according to Terry Eagleton (The Ideology of the Aesthetic 1990:28), the aesthetic is from the start “a contradictory, double‐edged concept”, how are seemingly innocent acts of viewing and consuming aesthetically pleasing landscapes implicated in the neoliberal politics of urban restructuring? Using contemporary Shanghai as a case study, this paper critically examines the role of the aesthetic in the politics of exclusion and urban segregation in post‐Socialist Shanghai where the restructuring and commodification of erstwhile public welfare housing have led to the rapid development of private “middle‐class” gated enclaves. A central objective of this paper is to excavate the underlying cultural politics of neoliberalism and demonstrate how the aestheticization of urban spaces in Shanghai has become increasingly intertwined with and accentuated by neoliberal ideologies and exclusionary practices in the city. Imbricated in the pristine neighborhoods of Shanghai's gated communities are the fault lines of social division and class distinction that are rapidly transforming urban China.     

Sociospatial Residential Dynamics: Stability and Instability within a Self-Organizing City

Conceiving the city as a self-organizing system we highlight and examine the phenomena of residential sociospatial segregation in a city and the existence and role of local regions of instability within an otherwise stable urban system. It is argued that the emergence of local pockets of sociospatial instability is governed (among other things) by a self-organization principle we term the captivity principle. The latter is essential to the systemic stability and reproduction of the city as a whole. The discussion is elaborated by reference to empirical evidence and by means of “city games” played on City, a cellular automata simulation model we have specifically designed for this purpose.     

Sites of Social Centrality and Segregation: Lefebvre in Belfast,a “Divided City”

Abstract: This paper applies Henri Lefebvre's ideas on participatory democracy and spatial politics to the context of “divided cities”, a milieu often overlooked by scholars of Lefebvre. It considers, via Lefebvre, how the heterogeneous and contradictory statist methods to deal with ethno‐national violence in Belfast have in effect increased segregated space. State‐led approaches to public space as part of conflict transformation strategies appear contradictory, including attempts to “normalize” the city through inward capital investment and cultural regeneration, encouraging cosmopolitan notions of inclusive “civic identity”, and reinforcing segregation to contain violence. These processes have done little to challenge sectarianism. However, as Lefebvre suggests that dominant representations of space cannot be imposed without resistance, this paper considers the alternative strategies of a disparate range of groups in Belfast. These groups have formed cross‐cleavage networks to develop ritualized street performances which challenge the programming of public space for segregation.     

EXPERIENTIALITY AND “NARRATIVE REFERENCE,” WITH THANKS TO THUCYDIDES1

Lately, the concept of experience, which postmodernist theoreticians declared dead, has seen a renaissance. The immediacy of experience seems to offer the possibility of reaching beyond linguistic discourses. In their attempt to overcome the “linguistic turn,” scholars such as Ankersmit, Gumbrecht, and Runia pit experience against narrative. This paper takes up the recent interest in experience, but argues against the opposition to narrative into which experience tends to be cast. The relation between experience and narrative is more complex than is widely assumed. Besides representing and giving shape to experience, narratives are received in the form of a (reception) experience. Through their temporal structure, narratives are crucial to letting us re‐experience the past as well as to representing the experiences of historical agents. This potential of narrative is nicely illustrated by Thucydides' History of the Peloponnesian War in which “side‐shadowing” devices restore history's experientiality. Through “side‐shadowing,” narrative can challenge the tendency toward teleologies inherent in merely retrospective histories and can re‐create the openness intrinsic to the past when it still was a present. However, the “side‐shadowing” devices used by Thucydides are fictional. To conceptualize the price and gain of “side‐shadowing” in historiography, the paper advances the concept of a “narrative reference” (a concept analogous to Ricoeur's “metaphorical reference”). Introspection, speeches, and other “side‐shadowing” devices sacrifice truth in a positivist sense, but permit a second‐level reference, namely to history's experientiality. In a final step, the paper turns toward modern historians—most of whom are reluctant to use the means of fiction—to briefly survey their attempts at restoring the openness of the past.     

“SEEING” THE PAST: TEXT AND QUESTIONS OF HISTORY IN THE RĀJATARAṄGIṆĪ

Traditional scholarly opinion has regarded Kalha?a's Rājatara?gi?ī, the twelfth‐century Sanskrit chronicle of Kashmiri kings, as a work of history. This essay proposes a reinvestigation of the nature of the iconic text from outside the shadow of that label. It first closely critiques the positivist “history hypothesis,” exposing its internal contradictions over questions of chronology, causality, and objectivity as attributed to the text. It then argues that more than an empiricist historical account that modern historians like to believe it is—in the process bracketing out integral rhetorical, mythic, and didactic parts of the text—the Rājatara?gi?ī should be viewed in totality for the kāvya (epic poem) that it is, which is to say, as representing a specific language practice that sought to produce meaning and articulated the poet's vision of the land and its lineages. The essay thus urges momentarily reclaiming the text from the hegemonic but troubled understanding of it as history—only to restore it ultimately to a more cohesive notion of historicality that is consistent with its contents. Toward this end, it highlights the concrete claim to epistemic authority that is asserted both by the genre of Sanskrit kāvya generally and by the Rājatara?gi?ī in particular, and their conception of the poetic “production” of the past that bears a striking resonance with constructivist historiography. It then traces the intensely intertextual and value‐laden nature of the epistemology that frames the Rājatara?gi?ī into a narrative discourse on power and ethical governance. It is in its narrativity and discursivity—its meaningful representation of what constitutes “true” knowledge of time and human action—that the salience of the Rājatara?gi?ī may lie.     

A “Scented Declaration of Progress”: Globalisation,Afropolitan Imagineering and Familiar Orientations

Branded as “Africa's first luxury perfume”, the Scent of Africa perfume is a “scented declaration of progress”. Particularly fascinating is the commercial advertisement for the perfume, which I argue to be an “Afropolitan Imagineering” project that is intended to signal Africa's rise and its new association with global cosmopolitanism. At first glance, the Scent of Africa perfume advertisement seems to point to the ways in which Imagineering projects can reproduce colonial discourses about Africanness. However, in this article, I suggest that we complicate the advertisement and examine its subversive potential to decentre whiteness and celebrate Africanness while writing Africa into the world. Despite this subversion, I conclude that African worlding practices should disinherit the familiarity of Eurocentric geographic determinism that is embedded in Afropolitan Imagineering and instead become informed by afro‐futuristic imaginings and disidentification politics.     

Deracinated Dispossessions: On the Foreclosures of “Gentrification” in Oakland,CA

This paper challenges dominant geographies of urban theory by conceptualising the dynamics of displacement in Oakland through place‐specific histories of racial/spatial politics. It argues that the repeated transposition of a San Francisco‐based model of “tech gentrification” results in deracinated dispossessions, or accounts of displacement uprooted from grounded histories of racial violence and resistance. It also argues that, while urban scholars acknowledge the role of historical difference in contouring dispossessions in metropolitan versus postcolonial cities, this consideration should be broadened to account for the racial/colonial dimensions of urbanism in the US as well. Treating Oakland as a “crossroads of theory”, this paper joins calls for a deeper engagement between postcolonial urban studies and critical race and ethnic studies from North America. Drawing upon the authors’ activist and empirical work, it contends that “thinking from Oakland” demands a foregrounding of racial capitalism, policing, and refusal.     

The Colocation Quotient: A New Measure of Spatial Association Between Categorical Subsets of Points. 协同区位商：点集分类子集间空间关联性的新度量标准

This article presents a new metric we label the colocation quotient (CLQ), a measurement designed to quantify (potentially asymmetrical) spatial association between categories of a population that may itself exhibit spatial autocorrelation. We begin by explaining why most metrics of categorical spatial association are inadequate for many common situations. Our focus is on where a single categorical data variable is measured at point locations that constitute a population of interest. We then develop our new metric, the CLQ, as a point‐based association metric most similar to the cross‐k‐function and join count statistic. However, it differs from the former in that it is based on distance ranks rather than on raw distances and differs from the latter in that it is asymmetric. After introducing the statistical calculation and underlying rationale, a random labeling technique is described to test for significance. The new metric is applied to economic and ecological point data to demonstrate its broad utility. The method expands upon explanatory powers present in current point‐based colocation statistics.     

“FUTURE PAST”: TIME AND TELEOLOGY IN (ANCIENT) HISTORIOGRAPHY

The historian's account of the past is strongly shaped by the future of the events narrated. The telos, that is, the vantage point from which the past is envisaged, influences the selection of the material as well as its arrangement. Although the telos is past for historians and readers, it is future for historical agents. The term “future past,” coined by Reinhart Koselleck to highlight the fact that the future was seen differently before the Sattelzeit, also lends itself to capturing this asymmetry and elucidating its ramifications for the writing of history. The first part of the essay elaborates on the notion of “future past”: besides considering its significance and pitfalls, I offset it against the perspectivity of historical knowledge and the concept of narrative “closure” (I). Then the works of two ancient historians, Polybius and Sallust, serve as test cases that illustrate the intricacies of “future past.” Neither has received much credit for intellectual sophistication in scholarship, and yet the different narrative strategies Polybius and Sallust deploy reveal profound reflections on the temporal dynamics of writing history (II). Although the issue of “future past” is particularly pertinent to the strongly narrative historiography of antiquity, the controversy about the end of the Roman Republic demonstrates that it also applies to the works of modern historians (III). Finally, I will argue that “future past” alerts us to an aspect of how we relate to the past that is in danger of being obliterated in the current debate on “presence” and history. The past is present in customs, relics, and rituals, but the historiographical construction of the past is predicated on a complex hermeneutical operation that involves the choice of a telos. The concept of “future past” also differs from post‐structuralist theories through its emphasis on time. Retrospect calms the flow of time, but is unable to arrest it fully, as the openness of the past survives in the form of “future past” (IV).     

“Die wissenschaftliche Ausbildung des Arztes ist eine Culturfrage …”. Über das Verhältnis von Wissenschaftsanspruch,Bildungsprogramm und Praxis der Medizin

The article shows that the elite, nationalistic and imperial mentality of German medicine in the second half of the nineteenth century was closely connected to its aim to be understodd as a natural science. With this in view leading representatives of German medicine propagated a scientific approach to man and nature instead of the traditional values of humanistic education (“Bildung”). One of the most important consequences of the new scientific ideal in medicine — integration in governmental planning, the change in professionel status of doctors, the increasing tendeny to recognize biologistic ideologies — was the loss of the medical ideal of the ars medica, a subject which has not received sufficient thematic attention. This theme is explored in the third part of the article.