Geography and development

The most striking fact about the economic geography of the world is the uneven spatial distribution of economic activity, including the coexistence of economic development and underdevelopment. High-income regions are almost entirely concentrated in a few temperate zones, half of the world's GDP is produced by 15 percent of the world's population, and 54 percent of the world's GDP is produced by countries occupying just 10 percent of the world's land area. The poorest half of the world's population produces only 14 percent of the world's GDP, and 17 of the poorest 20 nations are in tropical Africa. The unevenness is also manifest within countries and within metropolitan concentrations of activity. Why are these spatial differences in land rents and wages not bid away by firms and individuals in search of low-cost or high-income locations? Why does economic activity cluster in centers of activity? And what are the consequences of remoteness from existing centers? The authors argue that understanding these issues is central for understanding many aspects of economic development and underdevelopment at the international, national, and subcontinental levels. They review the theoretical and empirical work that illuminates how the spatial relationship between economic units changes and conclude that geography matters for development, but that economic growth is not governed by a geographic determinism. New economic centers can develop, and the costs of remoteness can be reduced. Many explicit policy instruments have been used to influence location decisions. But none has been systematically successful, and many have been very costly-in part because they were based on inappropriate expectations. Moreover, many ostensibly nonspatial policies that benefit specific sectors and households have spatial consequences since the targeted sectors and households are not distributed uniformly across space. These nonspatial policies can sometimes dominate explicitly spatial policies. Further work is needed to better understand these dynamics in developing countries.Economic Theory&Research,Decentralization,Labor Policies,Environmental Economics&Policies,Banks&Banking Reform,Banks&Banking Reform,Municipal Financial Management,Health Economics&Finance,Economic Theory&Research,Environmental Economics&Policies

Neuroprotective effects of metabotropic glutamate receptor ligands in a rodent 6-hydroxydopamine model of Parkinson's disease

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The Dynamics of City Formation

This paper examines city formation in a country whose urban population is growing steadily over time, with new cities required to accommodate this growth. In contrast to most of the literature there is immobility of housing and urban infrastructure, and investment in these assets is taken on the basis of forward-looking behavior. In the presence of these fixed assets cities form sequentially, without the population swings in existing cities that arise in current models, but with swings in house rents. Equilibrium city size, absent government, may be larger or smaller than is efficient, depending on how urban externalities vary with population. Efficient formation of cities with internalization of externalities involves local government intervention and borrowing to finance development. The paper explores the institutions required for successful local government intervention.

Separation of Lift-Generated Vortex Wakes Into Two Diverging Parts

As part of an ongoing study of the spreading rate of lift-generated vortex wakes, the present investigation considers possible reasons as to why segments of lift-generated wakes sometimes depart from the main part of the wake to move rapidly in either an upward or downward direction. It is assumed that deficiencies or enhancements of the lift carry over across the fuselage-shrouded wing are the driving mechanism for departures of wake-segments. The computations presented first indicate that upwardly departing wake segments that were observed and photographed could have been produced by a deficiency in lift carryover across the fuselage-shrouded part of the wing. Computations made of idealized vortex wakes indicate that upward departure of a wake segment requires a centerline reduction in the span loading of 70% or more, whether the engines are at idle or robust thrust. Similarly, it was found that downward departure of wake segments is produced when the lift over the center part of the wing is enhanced. However, it was also found that downward departures do not occur without the presence of robust engine-exhaust streams (i.e., engines must NOT be at idle). In those cases, downward departures of a wake segment occurs when the centerline value of the loading is enhanced by any amount between about 10% to 100%. Observations of condensation trails indicate that downward departure of wake segments is rare. Upward departures of wake segments appears to be more common but still rare. A study to determine the part of the aircraft that causes wake departures has not been carried out. However, even though departures of wake segments rarely occur, some aircraft do regularly shed these wake structures. If aircraft safety is to be assured to a high degree of reliability, and a solution for eliminating them is not implemented, existing guidelines for the avoidance of vortex wakes [1,3] may need to be broadened to include possible increases in wake sizes caused by vertical departures of wake segments. Further study may indicate that it is not possible to modify existing aircraft enough to prevent wake departures. Wake-avoidance guidelines must then be adjusted to provide the desired degree of safety. It appears that steps to avoid upwardly moving wake segments have already been incorporated into the avoidance procedures used for aircraft on approach to runways at the Frankfurt Airport [6,7]. The uncertainty in the prospects for compromises in flight safety caused by rapidly upwardly or downwardly moving wake segments suggest that it be specified that aircraft do not fly above or below each other during operations in the airport vicinity where aircraft are likely to be closely spaced [20]

Building the city: sunk capital, sequencing andinstitutional frictions

This paper models a growing city, and focuses on investment decisions and consequent patterns of land use and urban density. We distinguish between formal and informal sector construction. The former can be built tall (at a cost), but structures once built are durable and cannot be modified. Investments are based on expectations about future growth of the city. In contrast, informal structures are malleable and do not involve sunk costs. As the city grows areas will initially be developed informally, and then formally; formal areas are redeveloped periodically. This process can be hindered by land right issues which raise the costs of converting informal to formal sector development. The size and shape of the city are sensitive to the expected returns to durable investments and to the costs of converting informal to formal sector usage. We take the model to data on the built environment for Nairobi, to study urban growth and change between 2004 and 2015 in a context where population is growing at about 4% a year. We study the evolution of building footprints and heights, development at the fringe, infilling, and redevelopment of the formal sector

Building the city: from slums to a modern metropolis

We model the building of a city, estimate parameters of the model, and calculate welfare losses from institutional frictions encountered in changing land-use. We distinguish formal and slum construction technologies; in contrast to slums, formal structures can be built tall, are durable, and nonmalleable. As the city grows areas are initially developed informally, then formally, and then redeveloped periodically. Slums are modelled as a technology choice; however, institutional frictions in land markets may hinder their conversion to formal usage that requires secure property rights. Using unique data on Nairobi for 2003 and 2015, we develop a novel set of facts that support assumptions of the model, estimate all parameters of the model, and calculate welfare losses of conversion frictions. We track the dynamic evolution of the city and compare it with model predictions. In the core city formal sector, about a third of buildings were torn down over 12 years and replaced by buildings on average three times higher. For slums in older areas near the centre, even after buying out slumlords, overcoming institutional frictions would yield gains amounting to about $18,000 per slum household, 30 times typical annual slum rent payments

Statistical description and comparison of Boston University Junior College Division Class of 1953 and Boston University Junior College Class of 1954.

Thesis (M.A.)--Boston Universit