In this context, packing is defined as the number of BUILT nodes (regions) monotonic relationship between constellation size (area) and the number of types of urban land use and, more specifically, different categories of residential land. (however defined) are nonlinearly related to traffic speed and density. Previous studies has a monotonic relationship to space mean speed. After testing. define urban very carefully and precisely and designate as rural that which is not urban. The only indicator with a monotonic relationship, increasing from.
Only a few UM studies exist, and none gives more than a cursory explanation and justification of the analogy. It is timely and necessary to undertake a thorough examination of its theoretical and practical aspects e. Conceptualization and Emergence of UM UM has been defined as the material and energy flows through a city.
Emphasis is placed on the efficiency with which resources are used.
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Rather than develop a theory of UM, though, researchers have explicated the concept through its usage. The Hypothetical City In a paper considered seminal, Wolman first invoked metabolism to describe a hypothetical city.
To set the stage, he asserted: Over a period of time these requirements include even the construction materials needed to build and rebuild the city itself. The metabolic cycle is not completed until the wastes and residues of daily life have been removed and disposed of with a minimum of nuisance and hazard Wolman An input—output I—O analysis summed the water, food, and fuel required by the city as well as the resulting sewage, refuse, and air pollutants Wolman Though the UM analogy provided a platform for discussing resources quantitatively, strict parallels to organismic metabolism were not drawn.
Indeed, Wolman only mentioned the concept; he did not expound a theory. He simply referenced metabolism to explain I—O analysis: If Wolman labeled the reliance of urban environments upon the natural world as metabolism, the Hong Kong study operationalized it by cataloging the rates of resource consumption and waste production, with additional analyses of energy, food, nutrients, and water supply Boyden et al.
This pioneering case study used previous mass-balance studies to characterize physical indicators of flows through the city and social variables affecting the population Newcombe et al.
This analysis was used to project the effects of urbanization on resource requirements for the turn of the century. A metabolic study of Tokyo considered the health and ecosystem risks of various material stocks and flows Akiyama It quantified the accumulation, and calculated the residual time, of chemical elements in urban waterways and synthetic compounds.
The study noted the high energy consumption in the city and the large amount of materials rapidly moving through the transport system, highlighting two approaches to UM: The former considered city-level macroscopic indicators and the latter looked at flows of materials and their controls. Twenty-five years after the Hong Kong study, material flow analysis and emergy evaluation were contextualized with the UM analogy: Newman presented material flows for Sydney, Australia in andshowing an increase through time in per capita resource inputs and most waste outputs.
Several metabolic concepts were considered, including the anthropogenic metabolism i. The metabolism of the city was then linked to the hinterland.
A UM study of Toronto estimated the inflows of food, water, and manmade energy and the outflows of air emissions, residential solid waste, and wastewater Sahely et al. The study showed inputs increased more than outputs between and and also compared the per capita material flow for Sydney, Hong Kong, and Toronto in terms of food, water, energy, emissions, solid wastes, discharged wastewater, and biochemical oxygen demand.
Further international comparisons were made by Decker et al. They defined the UM concept: Specifically, UM provides a framework for describing the consumption of land and energy and expulsion of waste by economic activity. Usefully, UM has led researchers to catalog the resources used, consumed, and transformed into waste. However, a city is a physical and biological system. In doing so, it addresses self-selection, uses a series of dependent variables based on longitudinal data, and proceeds at a detailed spatial level.
In particular, it examines the opportunities available to displaced workers in terms of the spatial distribution of potentially-available jobs by industry and earnings. This research is made possible by the availability of a new confidential Census data source: These data provide, for over 1million U.
They are longitudinal, permitting estimation of models explaining rehiring after a separation. Likewise, measures of job accessibility are defined not only on the spatial distribution of employment but also based on the spatial distribution of new hires. These areas vary in size, changes in manufacturing employment, and opportunities in alternate industry sectors. In line with economic theory, we treat these cost-earnings differentials as estimates of the value of amenities in different locations, or 'quality of life'.
Wage data comes from an individual level panel covering of the UK workforce allowing us to control for observable and unobservable characteristics of individuals as well as to correct for the effect of non-linearities in tax schedules. When controlling for observables, we show that housing costs rise one for one with the earnings of the average household. However, when we use movers to control for unobservables, we find that sorting leads us to understate the cost effect of living in the highest house price locations.
We rank labour markets, according to cost-earnings differentials and explore the factors leading to high 'quality of life'. In common with the existing literature we find that climate and low levels of pollutants or their sources appear to be one of the main drivers. Evidence on the Role of Entry and Exit A vast array of research has focused on the earnings premium greater economic density appears to afford to workers in a given location. In this paper, we explore the role of establishment entry, exit, and growth in generating the positive relationship between earnings and density across locations observed in the data.
We focus our analysis on how these dynamic processes interact with the earnings-density relationship across the distribution of earnings within a metropolitan area. We motivate our work with recent research by Combes et al.
Definition of monotonic, and implications for using Spearman's correlation - Cross Validated
We use a rich panel of establishment micro data for the U. Our preliminary findings show that the earnings of both entrants and exits exhibit a positive relationship to urban density.
This is true in absolute terms, as well as when their earnings are normalized by the earnings of incumbents. Since both entrants and exits have lower earnings than incumbents do, on average, these results suggest that entry and exit generate a greater compression of the earnings distribution in more dense metropolitan areas. The recorded geography of dialects provides an ideal opportunity to comprehensively portray deep cultural differences at the local level.
Dialects have been shaped during centuries in a process of linguistic evolution and reflect domains of cultural identity that would otherwise be immeasurable.
We then show in a gravity analysis that cross-regional migration in the period is positively affected by historical dialect similarity. This points at highly time-persistent cultural borders that impede economic exchange across regions of the same country. Finally, we also investigate the effects of dialect similarity on intra-national trade flows in Germany.
Evidence from the Roestigraben This paper studies the role of culture in shaping unemployment outcomes. The empirical analysis is based on a spatial regression discontinuity design with local comparisons across a language barrier in Switzerland.
This 'Roestigraben' separates cultural groups, but neither labor markets nor political jurisdictions. Local contrasts across thel anguage border identify the role of culture for unemployment.
Culture and Diversity in Knowledge Creation What are the costs and benefits of knowledge diversity? Does the creation of a culture of ideas in common among a population raise or lower productivity? What role is played by interregional interaction among researchers? Can a real technological increase in the cost of collaboration and cost of public knowledge flow between regions increase welfare? In our framework, a culture is a set of ideas held exclusively by residents of a location.
In general in our model, the equilibrium path generates separate cultures in different cities. As a result, equilibrium productivity is lower relative to the situation when there are multiple cultures and workers are more diverse. In other words, it is better to differentiate workers spatially so that they become more diverse and develop more diverse cultures.
Is There a Metabolism of an Urban Ecosystem? An Ecological Critique
This increases productivity relative to the situation where there is only one culture and workers are relatively homogeneous. University of California, Berkeley Social Networks and Interactions in Cities We develop a model where both the urban space and the social space are explicitly taken into account.
Agents are located in a social network. Each agent derives utility from consumption but also from interactions with their direct friends. Each agent optimally decides how many visits to make to the city center given that there is a trade off between the positive externalities they obtain from interacting with other agents in the center and the transportation costs. There are only two locations in the city, the center and the suburbs, and only agents living in the suburbs pay transportation costs to commute to the center.
We show that more central agents in the social space tend to live in the city center and interact more with other agents that peripheral agents. We also show that denser networks lead to more aggregate social activities. We finally show that the market equilibrium is not optimal because of social externalities.
We determine the value of the social-interaction subsidy that can restore the first best outcome. Theories of Agglomeration Pikes Peak Chair: The answers to these questions are essential in assessing urban policy. A dynamic model is used to produce the life-cycle of a city. An important innovation of this dynamic model is that cities are formed by individuals without large agents such as developers.
The previous literature on self-organized city formation has been limited by a coordination problem, which this dynamic model has solved. The dynamic model is able to match the empirical facts that almost all cities grow through time, city growth tends be sequential, and cities experience periods or rapid growth. In addition the behavior of cities that are able to limit mobility of migrants is analyzed.
A system of cities that are able to limit migration through zoning greenbelts around the city and density within the city are found to be undersized relative to the socially efficient population level.
A system of cities that are unable to exclude migrants are found to be oversized relative to the socially efficient population level. However, a system of cities that are able to charge migrants a fee for entering the city are found to be efficiently distributed. Individuals consume differentiated goods or services and firms purchase differentiated inputs or services in product or service markets where firms compete under monopolistic competition.
Workers rent their residential lots in an urban land market and contribute to the production of differentiated goods and inputs. We show that firms and workers co-agglomerate and endogenously form a city. We characterize and discuss the spatial distribution of firms and consumers in such cities on one- and two-dimensional spaces linear city and planar city.
We show that final demand and input-output linkages raise the urban density and reduce the city spread. We finally show that a city is too much dispersed compared to the social optimum.
An auction approach I propose a model of a city in which uncompensated knowledge transfers to entrepreneurs are bids by experts in auctions for jobs. The model derives from the key ideas about how knowledge differs from other inputs of production, namely that knowledge must be possessed for its value to be assessed Arrowand that knowledge is freely reproducible.
The model identifies conditions under which knowledge 'spills' in non-market interactions, as opposed to being transacted in markets. Endogenous agglomeration economies result from growth in the number of meetings between experts and entrepreneurs, and from heightened competition for jobs between experts. Wen-Tai Hsu Thomas J.
The selection mechanism can be decomposed into two stages: In a larger market, the mill prices are lower, the average plant size is larger, the selection rate is smaller, but the ex post average productivity is larger. We make several points different from the literature: Selection and agglomeration are intertwined, the variance of ex post productivity distribution can be larger in the larger market, and the selection pressure across firms with different productivity differs in a continuous way and hence does not imply a minimum cutoff for survival.
Education and Sorting Longs Peak Chair: In this model, charter schools offer an alternative to neighborhood public schools. In the second stage, students choose among the available schools. We estimate the model using data for the DC school district. We use our parameter estimates to investigate the potential effects of changes in charter school legislation on charter school entry, and on post-entry outcomes such as enrollment and achievement. Transfers that redistribute resources equitably across regions will likely target areas with individuals of low earnings potential or low real incomes.
Examining these metrics in practice, federal transfer differences across Canadian provinces are neither efficient nor equitable, but exacerbate pre-existing inefficiencies and underfund minorities.
Total locational inefficiencies cost the economy 0. Previous research has shown that school quality is capitalized into house prices Black, ; Figlio and Lucas, and thus homeowners are likely to be sensitive to the quality of the local public school when making the decision of whether or not to invest in their property. Thus homeowner investment decisions play a large role in determining the trajectories of urban neighborhoods. Understanding the interactions between urban schools and urban homeowners can help inform policy decisions surrounding urban revitalization.
Those spillovers augment private investment in idea discovery and human capital and are central to modern theories of spatial equilibrium and endogenous economic growth Romer andLucas and and Glaeser and Gottleib Upon accounting for regional differentials in skill-based compensation, cost-of-living, and natural and other amenities, model estimation indicates that high-skill migrants attach significant importance to knowledge and human capital spillovers arising from FDI and human capital concentration in destination regions.
Among low-skill migrants, the importance of spillover effects is considerably damped, reflecting institutional and other barriers to social interactions and human capital investment in destination cities.
Moreover, results suggest important potential welfare gains from removing barriers for low-skill migrants to access spillover benefits. Maria Marta Ferreyra 05A. Is it unobserved heterogeneity or externalities? The aim of our paper is to develop a methodology that allows us to exploit the micro-geographic nature of firm location data while allowing us to disentangle the determinants of localization unobserved heterogeneity vs interactions.
To this end, we blend standard spatial econometric techniques with a Monte Carlo approach using firm-level data for a large sample of Canadian manufacturing firms. We discuss existence of equilibrium of and characterize the stationary distribution of firms in each location.
The parameters of the model can be estimated using a nested fixed point algorithm. We implement the estimator using data collect by Dunn and Bradstreet for the Pittsburgh metropolitan area.
The data suggest that firms located in the city are older and larger than firms located outside the urban core. As a consequence they use more land and labor in the production process. However, they face higher rental rates for land and office space.
As a consequence they operate with a higher employee per land ratio. We find that our model explains these observed features of the data well. Finally, we consider the impact of different relocation policies that provide targeted subsidies to new start-ups and superstar firms. Why New York, Los Angeles and Detroit attract the greatest minds as well as the unskilled We propose a theory of skill mobility across cities.
It confirms the well documented city size-wage premium: Yet, because this premium reflects higher house prices, this does not necessarily imply that this stochastic dominance relation also exists in the distribution of skills. Our model entails evidence quite to the contrary: We show that this is due to patterns of sorting across cities in a model with mobility.
Our model predicts a 'Sinatra' as well as an 'Eminem' effect: Based on our theory, the pattern of spatial sorting can be explained by a simple technology with varying elasticity of substitution by skill. Using CPS data on wages and Census data on house prices, this technology with the elasticity of substitution decreasing in skill density is consistent with the observed patterns of skills.
We first calculate frictions in labor supply and demand decisions as well as productivity in most MSAs in the U. Using this theory, we can relate productivity, frictions and amenities, to land rents and MSA population size. We then implement this decomposition in the data.
The results show that there is a mechanism by which more efficient cities are larger but, as result, also exhibit more frictions. That is, size involves frictions through congestion and other negative effects of agglomeration. Cities that exhibit larger frictions than the ones implied by this size-productivity mechanism are smaller and have lower rents. We show that frictions and productivity are the main determinants of differences in city sizes.
Counter-factual exercises allow us to calculate city sizes absent efficiency, excessive frictions, or amenity differences.
The Case of Spain This paper describes a quantitative model developed to account for the change in the level of house prices boom-and-bust cycle in Spain. The driving forces behind the housing boom are residential investment, immigration, current account de cits, and the elimination of land regulation.
The model emphasizes the interaction of housing supply determined by the existing stock of residential investment and new construction with market demand. A calibrated version of the model for the Spanish economy replicates the key aggregate of the economy in The model predicts that a change in observed fundamentals can rationalize at least 84 percent of the recent boom in the value of housing capital.
The model suggests that without large current account de cits and demographic changes the housing boom could have been much smaller. Some conservative predictions quantify adjustments that range between and 29 percent.
We explicitly model locational choice. Housing services derive positive utility but are decayed away from the city center.
Is There a Metabolism of an Urban Ecosystem? An Ecological Critique
Our model enables a full characterization of the dynamic paths of housing as well as housing and land prices. The calibrated model is then used to quantitatively assess the long-run and short-run consequences of changes in preferences and technologies. According to our estimates, land accounts for percent of housing costs, labor 64 percent, and mobile capital 11 percent.
The estimated elasticity of substitution between factors of production is greater than one, although it is not precisely estimated. Furthermore, we are able to estimate differences in total factor productivity in the housing sector across cities.
A one-standard deviation increase in the regulatory environment is associated with an 8 percent increase in housing costs, while a similar increase in undevelopable land is associated with a 7 percent increase. Overall, the most productive housing environments are found in the West Central North and South regions, while the least productive are in the Pacific region. Productivity in housing is negatively correlated with measures of productivity in the tradable sector.