High-density Development Research Articles

High-Density Lipoprotein and the Dynamics of Atherosclerotic Lesions

Plump et al1 reported in 1994 that the expression of a human transgene for apoA-I, the major apolipoprotein of HDL, in apoE knockout mice dramatically reduced lesion formation. In the present issue of Circulation , Rong et al2 demonstrate that the composition and structure of advanced atherosclerotic plaques can be significantly altered by the expression of this same transgene. Rong and colleagues2 used a novel transplant model. They fed apoE knockout mice a Western diet for 6 months to generate advanced lesions. Subsequently, they surgically removed portions of the aorta from these mice and transplanted them into the aortas of syngeneic mice on a chow diet, some of which also expressed the transgene for human apoA-I. The recipient mice expressing the human transgene had ≈2.5-fold higher HDL cholesterol levels and expressed 130±15 mg/dL of human apoA-I. The non-HDL cholesterol levels were approximately half of those that had been present in the donor mice and were similar, regardless of whether the transgene was expressed or not. Five months later, despite non-HDL cholesterol levels that were half those of the donor mice, there was progression in the transplanted lesions, although there was less progression in the mice expressing the human apoA-I transgene. However, the characteristics of the lesions were dramatically different. The recipients expressing the transgene had a >80% decrease in lesion macrophage area and a >300% increase in smooth muscle cell content, with most of the changes occurring in the superficial subendothelial layer. See p 2447 In another study, Reis et al3 found that transplanting aortic segments from apoE knockout mice on a Western diet with advanced lesions into the aortas of …

The Continuing Value of a Planned Community: Radburn in the Evolution of Suburban Development

Radburn was built at the edge of early 20th-century suburbs in Fair Lawn, New Jersey, in a time of transition between suburban development patterns. Although only a quarter of the original town plan was completed because of the Great Depression, its distinctive characteristics have remained unchanged. Its location on the border between early 20th-century suburban development, which is based on a strict grid system, and post-World War II suburban development allows us to compare Radburn's distinctive values with other schemes of residential development. The paper finds that the Radburn model is still working. The pedestrian-oriented scheme encourages high transit use. The market still values Radburn's integration of high-density development with attractive public space and its complete pedestrian network as a premium in property value. Since many contemporary planners and designers are once again pursuing these Radburn values in New Urbanist schemes, they would do well to consider the Radburn model.

The Continuing Value of a Planned Community: Radburn in the Evolution of Suburban Development

Radburn was built at the edge of early 20th-century suburbs in Fair Lawn, New Jersey, in a time of transition between suburban development patterns. Although only a quarter of the original town plan was completed because of the Great Depression, its distinctive characteristics have remained unchanged. Its location on the border between early 20th-century suburban development, which is based on a strict grid system, and post-World War II suburban development allows us to compare Radburn's distinctive values with other schemes of residential development. The paper finds that the Radburn model is still working. The pedestrian-oriented scheme encourages high transit use. The market still values Radburn's integration of high-density development with attractive public space and its complete pedestrian network as a premium in property value. Since many contemporary planners and designers are once again pursuing these Radburn values in New Urbanist schemes, they would do well to consider the Radburn model.

What Does "Smart Growth Mean for Community Development?

Sprawling patterns of dispersed residential and commercial development are seen as wasteful of land, expensive to service, automobile-dependent, environmentally harmful, and, ultimately, community-defeating. The state of Maryland has enacted a package of "Smart Growth" programs to promote more compact development by targeting public infrastructure and providing financial incentives in designated growth areas. It is hoped that this strategy will result in less sprawl, higher density development, greater use of mass transit, a pedestrian orientation, more closely-knit communities, and a higher quality of life. But smart growth will succeed only if people in designated growth and redevelopment areas are able to improve the economic, social, and physical aspects of their communities. Smart growth must build the capacity of community residents to undertake land use planning and solve community problems. Otherwise, additional policies will be needed to link smart growth and community development.

Coastal-Zone Hazard Maps and Recommendations: Eastern Puerto Rico

A series of coastal zone hazard maps cover the area impacted by Hurricane Hugo (1989) in eastern Puerto Rico. The mapping strategy was to develop a tool for quick visualization of multiple hazards for use by coastal planners, managers, property owners, and potential property owners. The Puerto Rico shoreline is heavily developed in places and also highly compartmentalized in terms of shoreline types, geology, and adjacent shelf conditions. Hazards such as coastal erosion, storm surge, riverine flooding, landsliding, and seismic impact also may be compartmentalized. From a management perspective, resources therefore can be allocated on a compartment-by-compartment basis. Six types of hazards were considered in this investigation: (1) shoreline-setting hazards (long-term coastal problems), (2) marine hazards (short-term impacts of coastal storms), (3) earthquake and slope hazards (ground shaking, landslides, and liquefaction), (4) riverine hazards (historical floods), (5) development hazards (high-density development at risk or lowdensity development in extreme-hazard settings), and (6) engineering hazards (special cases in which shoreline engineering projects such as breakwaters or sand mining have significant detrimental effects on portions of the shoreline). Shoreline segments were ranked as being at extreme, high, moderate, or low risk, depending on the number of hazards present within that segment. These rankings are likely to change, gradually over decades with natural coastal evolution, more rapidly as human development infringes on the coastal zone, or in an instant during a severe storm. The hazard maps provide a basis for hazard mitigation and management recommendations.

The urban forestry programme in the heavily built-up milieu of Hong Kong

Urban forestry in Hong Kong is performed in exceptionally trying conditions due to the rampant occurrence of inherent physical and physiological constraints. The high-density development mode has resulted in cramped and poor-quality growing conditions both above and below the ground. The urban forest is unevenly scattered in a wide range of land uses with different canopy covers, species composition, tree dimensions and performance. Whilst overall tree number is limited, the floristic diversity is surprisingly high due to a combination of factors including a history of plant introduction, natural native diversity, and inheritance from pre-urbanization woodland and from former private gardens. Various participants and stakeholders play different roles in the urban forestry regime. Recent comprehensive studies of trees commissioned by the government at roadsides and urban parks provided valuable objective data and insight to design systematic and citywide management and planting plans. Trees dwelling in the peri- and intra-urban woodlands of high ecological and environmental values requires upgraded care and protection. The contribution of private developers in the urban greening programme needs to be encouraged with appropriate incentives, and be integrated into a comprehensive landscape plan.

Optimizing Transportation Infrastructure Planning with a Multiobjective Genetic Algorithm Model

Most transportation infrastructure planning studies are conducted with only a few alternative networks and land use scenarios. Generally, these studies analyze only a few transportation-related measures of effectiveness, such as vehicle-miles traveled, congestion, and air-quality emissions. When such a small subset of possible alternatives and variables is analyzed, it is probable that optimal alternative designs are not included. Ideally, all combinations of land use, infrastructure, and social variables would be examined; however, even a small city of 200 traffic zones with an average of 10 land uses will have more than 10200 possible zoning alternatives. A more efficient way to examine an extremely large search set of feasible designs is to employ artificial intelligence techniques to quickly narrow the number of alternatives to be considered. The use of a multiobjective genetic algorithm model to optimize land use, infrastructure, social, and fiscal variables is demonstrated. The model considers three primary objective functions: minimizing travel time, minimizing per capita cost (as related to property taxes), and minimizing land use change. A large number of constraints are used. A Pareto fitness function is used to develop a small set of optimal solutions. The model was applied to Provo, Utah, which is a fast-growing community. More than 1.9 million alternative designs were evaluated, and 195 optimal Pareto plans were found. The Pareto set of optimal solutions indicated that solutions clustering higher-density development along existing arterials were most likely to meet the objectives.

Landscape context of rural residential development in southeastern Wisconsin (USA)

Private on-site sewage systems serve residential development in rural landscapes throughout the United States. In the State of Wisconsin, three major types of private sewage systems facilitate residential development on sites that span gradients in slope, soil permeability, depth to bedrock, and depth to water-table. Conventionalsoil-absorption sewage treatment systems are constructed on sites with minimal physiographic constraints; more highly engineered alternative sewage treatment systems are installed on sites with moderate to severe constraints; holding tanks provide no on-site sewage treatment and are employed on sites with the most severe physiographic limitations. An environmental impact statement (EIS), prepared in 1979 on the proposed widespread use of alternative private sewage systems, suggested that alternative systems might facilitate in-fill development on poor sites near existing cities and lead to compact, higher density development patterns. The research reported in this paper tested the validity of this EIS scenario by comparing development patterns associated with a sample of conventional systems, alternative systems, and holding tanks installed during the 1980s in Ozaukee County, Wisconsin. Land use data, soils data, and other site attribute data were assembled and analyzed in a vector geographic information system (GIS). Because each type of private sewage system has a unique set of siting criteria, the three sets of sampled systems are located in significantly different physiographic regions within the County. Collectively, installations of all three systems facilitated scattered residential development throughout the rural landscape. This development consists of relatively small residential patches dispersed within an agricultural matrix. Wastewater management technology, if not constrained by public policies or other socioeconomic factors, can be an important anthropogenic factor influencing both the process and pattern of landscape change.

L.A. Story: A Reality Check for Transit-Based Housing

Proponents of high-density residential development near rail stations, or “transit-based housing,” argue that such projects will get more people onto trains, reduce developers' expenses, and potentially lower commuting costs, housing prices, and air pollution. This paper focuses on a separate question: Whatever virtues transit-based housing may have, what are its prospects? We find that transit-based housing faces a much steeper uphill battle than the conventional wisdom suggests. Cities' parochial fiscal and economic interests often conflict with transit-based housing, a view strongly supported by our behavioral analysis of zoning data for all 232 existing and proposed Southern California rail transit stations. Municipalities behave as if they prefer to use rail transit stations for economic rather than residential development. These results suggest that a planning framework should account for and reconcile the local as well as system-wide costs and benefits of transit-oriented policies. Regional incentives to encourage transit-oriented land uses are justified, for example, only where regional benefits outweigh both the direct cost of the intervention and the indirect costs to the tax and economic base of each affected community.

Trees and high-density urban development: Opportunities out of constraints

Trees and high-density urban development do not seem to be compatible in Hong Kong. The grave shortage of developable lands and the resultant tightly packed urban fabric have apparently left few plantable niches. A historical review of urban trees provides a baseline to gauge recent changes marked by rampant tree constraints and decimation. The contributions of the different government departments in greening some quarters of the city are assessed through the relevant policies and changing urbanisation patterns. The attitude of private developers and their combined effects on the cityscape are evaluated with reference to the quality and quantity of urban trees. The existing diffuse legislation and controls on tree preservation are difficult to enforce and cannot bring effective protection in private developments. To arrest further damage and to bring about a greener city, collaborative government and private-sector inputs and departure from past attitudes are needed. An assessment of the city matrix for potential planting and preservation suggests many opportunities for improvement. Recommendations on the approaches and methods to implement tree planting programmes are suggested.

Serum cholesterol, cholesteryl ester, and high-density lipoprotein development in newborn infants: Response to formulas supplemented with cholesterol and γ-linolenic acid

Healthy newborn infants were either breast-fed or randomly designated to receive a standard formula, formula plus cholesterol, or formula plus gamma-linolenic acid at birth. At 0, 7, and 30 days of life, the following variables were measured: cholesteryl esters (cholesteryl arachidonate, cholesteryl oleate, cholesteryl palmitate, and cholesteryl linoleate), high-density lipoprotein (HDL) cholesterol, apoproteins (A-I, A-II, B, C-II, C-III, and E), and the cholesterol and apoprotein A-I content of the HDL subfractions HDL-2b, HDL-(2a + 3a), and HDL-(3b + 3c). Breast-fed infants had higher serum levels of cholesterol, cholesteryl oleate, cholesteryl palmitate, cholesteryl arachidonate, and HDL-2b than had formula-fed infants. Addition of gamma-linolenic acid to formula raised cholesteryl-arachidonate levels, and cholesterol and gamma-linolenic acid raised serum HDL-2b levels compared with those produced by unsupplemented formula. Our data suggest that both exogenous cholesterol and gamma-linolenic acid contribute to the maturation of HDL particles associated with human milk consumption in newborn infants. They may also promote adequate delivery of cholesterol and arachidonic acid to the developing brain.

Southwestern Distribution and Habitat Ecology of Gryllodes supplicans

The “Indian house” or “decorated” cricket, Gryllodes supplicans (Walker), probably existed in Tucson, Ariz. from the late 1940s (verified 1963). Its local populations have expanded dramatically in Thcson and other Arizona cities over the past decade, and the species has extended its range to include other southwestern United States cities. It is found in urban ecosystems in the arid Southwest from sea level to 750 m and is most numerous in high-density residential developments. It is distributed along the Pacific coast of southern California, and north along the Colorado river into Nevada below 36° N latitude. This is the first report of the natural occurrence of G. supplicans in the United States outside of Florida. In Thcson, G. supplicans populations fluctuate with temperature and rainfall. Populations attain highest levels in the hot rainy months ofJuly and August. The origin of the southwestern United States population is not known, but its recent dramatic geographical and ecological expansion suggests that urban demes have coalesced coincident with urbanization and that the Southwest population may have evolved greater tolerance for arid environments.

Urban Commuting Journeys Are Not "Wasteful"

Do urban workers commute too much? Bruce Hamilton (1982) was the first to raise the question whether urban workers' commuting journeys are too long or, in his terms, "wasteful." He argued that the monocentric urban model predicts that workers' commuting journeys will be minimized. To test the model, he calculated the minimum commuting journey length for the average worker in a group of U.S. cities and compared the results to the actual average commuting journey length for those workers. He assumed that any difference between the two figures was "wasteful commuting." He found that the average minimum commuting distance was only 1.1 miles, but the average distance actually commuted by workers in those cities was 8.7 miles, or nearly eight times as great. Hamilton therefore concluded that the monocentric urban model has little predictive value concerning commuting behavior and that actual commuting behavior could be predicted just as well using an assumption that commuting is random. Commuting behavior is a central feature of any model that purports to explain urban residential and job location choice. Hamilton's assertion that the monocentric urban model has little predictive value concerning commuting behavior therefore strikes at the heart of

Aga Khan Program for Islamic Architecture, "Design for High-Density Development" (Book Review)

Aga Khan Program for Islamic Architecture, "Design for High-Density Development" (Book Review)

The status and prospects of urban trees in Hong Kong

The status and prospects of urban trees in Hong Kong are evaluated with information gathered from questionnaires and a tree survey. Planting and maintenance responsibilities fall to four government departments plus the private sector. Species composition is unevenly distributed, with five popular species constituting over half of the trees sampled. The numbers of introduced and cultivated trees far exceed those of native and voluntary ones. Species-selection without an evaluation programme is generally conservative, but gradual shifts in preference are discernible. The multifarious physical constraints in both the above-ground and subterranean environments that pose stringent limits on the number of potential planting sites and the growth of existing trees are elaborated. Typhoons, which could periodically cause widespread damage, often regardless of species and location, could only be partially mitigated by more comprehensive preventive measures. Pests and diseases which have not received detailed study are apparently mild. Vandalism, which damages roughly 10–15% of trees planted, could be alleviated by planting more heavy standard trees, but their supply is limited because of inadequate nursery space. The chronic shortage of tree staff aggravated by a high job mobility, due mainly to comparatively low remuneration and poor promotion prospects, creates a bottleneck in the tree programme. For the future, a city-wide tree survey together with a computer database are essential for efficient management, maintenance and research. The existing, rather lax statutory control should be consolidated and tightened, with authority being given to a single department which should be adequately supported by supervisory staff. Land could be zoned specifically, like other land-uses, for tree planting, and this could be more generous and spatially more evenly distributed to allow penetration of greenery into wider parts of the city. The potential in urban renewal areas where land could be released and reserved for planting should be realized as far as possible. Overall, rising aspirations for better environmental quality could be achieved by a combination of high-density vertical developments and strategically situated open spaces liberally adorned by landscape planting.

Mass Transport for High‐Rise High‐Density Living

Interactions between transportation, especially mass transportation, and high-rise, high-density living pose interesting questions. Attempts were made to measure these in typical major cities of the United States and in several other countries. It was generally found that historically, transportation has done much to shape all cities. In countries where government policy fosters high-density residential development, transit is an especially effective tool in shaping development, regardless of density. Transportation planners can make important contributions in planning high density. Transit and high density living can be mutually supportive, but one does not necessarily assure the other where free market real estate conditions prevail.

The Pinelands National Reserve: An Ecosystem Approach to Management

The history of the designation of the New Jersey Pine Barrens as the nation's first National Reserve is reviewed, and the natural features and land-use history of the Barrens are described. Federal legislation created the Pinelands National Reserve, and state legislation endorsed the establishment of the Pinelands Commission, which developed land-use regulations in its Comprehensive Management Plan. The regulations provide for a continuum of protection, ranging from maintenance of pristine conditions to high-density development in designated areas. Continued maintenance and enhancement of Pinelands ecosystems will depend on appropriate application of existing knowledge and future studies in such areas as nutrient transfer, the role of fire in nutrient dynamics, sustainable aquifer yields, and the effects of ecosystem fragmentation. (Accepted for publication 21 October 1983)

SEDIMENT METALS ACCUMULATION IN A SUBURBAN LAKE

ABSTRACT Lake Hopatcong is a 1,087 ha lake located in the suburban New York metropolitan area in Sussex and Morris Counties, N.J., and is the head waters of the Musconetcong River in the Delaware River Drainage Basin. The lake watershed is 5,483 ha in area with 71 percent forested and 25 percent in high-density residential development that is clustered around the immediate shoreline of the lake. The recreational use of the lake is extremely heavy, with an excessive number of large motor boats. Also, stormwater from the residential areas empties directly into the lake via storm sewers and direct runoff. Preliminary analysis of selected sediment samples indicated substantial levels of metals (especially lead) in the surficial sediments. As part of a Sec. 314 Lake Restoration study a series of 30 shallow sediment core samples were taken at various locations throughout the lake. These were analyzed for lead, aluminum, iron, zinc, mercury, cadmium and percent of solids. The results indicated significant concen...

Improving Energy Efficiency in Community Land-Use—Transportation Systems

The form of our cities is a major determinant of energy consumption, especially that related to the oil-consuming transport sector. This is particularly so in Australia, which is one of the most highly urbanized nations in the world with a high degree of dependence on automotive transport. The paper discusses planning changes to cope with future oil shortages in terms of modifying urban form, community hardware (buildings, infrastructure, and rolling stock), and community software (life-styles, rules and regulations, fuel economics, etc). Energy savings of at least 40% are possible in the larger cities through changes such as increasing vehicle operating costs, increasing vehicle occupancy, higher-density development, and shorter-trip behaviour. Subcentre development within the urban area is found to be less energy expensive than fringe or satellite development.