466 resultados para suburban sprawl
Resumo:
In many countries, high densities of domestic cats (Felis catus) are found in urban habitats where they have the potential to exert considerable predation pressure on their prey. However, little is known of the ranging behaviour of cats in the UK. Twenty cats in suburban Reading, UK, were fitted with GPS trackers to quantify movement patterns. Cats were monitored during the summer and winter for an average of 6.8 24 h periods per season. Mean daily area ranged (95 % MCP) was 1.94 ha. Including all fixes, mean maximum area ranged was 6.88 ha. These are broadly comparable to those observed in urban areas in other countries. Daily area ranged was not affected by the cat’s sex or the season, but was significantly larger at night than during the day. There was no relationship between area ranged and habitat availability. Taking available habitat into account, cat ranging area contained significantly more garden and other green space than urban habitats. If cats were shown to be negatively affecting prey populations, one mitigation option for consideration in housing developments proposed near important wildlife sites would be to incorporate a ‘buffer zone’ in which cat ownership was not permitted. Absolute maximum daily area ranged by a cat in this study was 33.78 ha. This would correspond to an exclusory limit of approximately 300–400 m to minimise the negative effects of cat predation, but this may need to be larger if cat ranging behaviour is negatively affected by population density
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The impact of 1973–2005 land use–land cover (LULC) changes on near-surface air temperatures during four recent summer extreme heat events (EHEs) are investigated for the arid Phoenix, Arizona, metropolitan area using the Weather Research and Forecasting Model (WRF) in conjunction with the Noah Urban Canopy Model. WRF simulations were carried out for each EHE using LULC for the years 1973, 1985, 1998, and 2005. Comparison of measured near-surface air temperatures and wind speeds for 18 surface stations in the region show a good agreement between observed and simulated data for all simulation periods. The results indicate consistent significant contributions of urban development and accompanying LULC changes to extreme temperatures for the four EHEs. Simulations suggest new urban developments caused an intensification and expansion of the area experiencing extreme temperatures but mainly influenced nighttime temperatures with an increase of up to 10 K. Nighttime temperatures in the existing urban core showed changes of up to 2 K with the ongoing LULC changes. Daytime temperatures were not significantly affected where urban development replaced desert land (increase by 1 K); however, maximum temperatures increased by 2–4 K when irrigated agricultural land was converted to suburban development. According to the model simulations, urban landscaping irrigation contributed to cooling by 0.5–1 K in maximum daytime as well as minimum nighttime 2-m air temperatures in most parts of the urban region. Furthermore, urban development led to a reduction of the already relatively weak nighttime winds and therefore a reduction in advection of cooler air into the city.
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Using a water balance modelling framework, this paper analyses the effects of urban design on the water balance, with a focus on evapotranspiration and storm water. First, two quite different urban water balance models are compared: Aquacycle which has been calibrated for a suburban catchment in Canberra, Australia, and the single-source urban evapotranspiration-interception scheme (SUES), an energy-based approach with a biophysically advanced representation of interception and evapotranspiration. A fair agreement between the two modelled estimates of evapotranspiration was significantly improved by allowing the vegetation cover (leaf area index, LAI) to vary seasonally, demonstrating the potential of SUES to quantify the links between water sensitive urban design and microclimates and the advantage of comparing the two modelling approaches. The comparison also revealed where improvements to SUES are needed, chiefly through improved estimates of vegetation cover dynamics as input to SUES, and more rigorous parameterization of the surface resistance equations using local-scale suburban flux measurements. Second, Aquacycle is used to identify the impact of an array of water sensitive urban design features on the water balance terms. This analysis confirms the potential to passively control urban microclimate by suburban design features that maximize evapotranspiration, such as vegetated roofs. The subsequent effects on daily maximum air temperatures are estimated using an atmospheric boundary layer budget. Potential energy savings of about 2% in summer cooling are estimated from this analysis. This is a clear ‘return on investment’ of using water to maintain urban greenspace, whether as parks distributed throughout an urban area or individual gardens or vegetated roofs.
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Sensible heat fluxes (QH) are determined using scintillometry and eddy covariance over a suburban area. Two large aperture scintillometers provide spatially integrated fluxes across path lengths of 2.8 km and 5.5 km over Swindon, UK. The shorter scintillometer path spans newly built residential areas and has an approximate source area of 2-4 km2, whilst the long path extends from the rural outskirts to the town centre and has a source area of around 5-10 km2. These large-scale heat fluxes are compared with local-scale eddy covariance measurements. Clear seasonal trends are revealed by the long duration of this dataset and variability in monthly QH is related to the meteorological conditions. At shorter time scales the response of QH to solar radiation often gives rise to close agreement between the measurements, but during times of rapidly changing cloud cover spatial differences in the net radiation (Q*) coincide with greater differences between heat fluxes. For clear days QH lags Q*, thus the ratio of QH to Q* increases throughout the day. In summer the observed energy partitioning is related to the vegetation fraction through use of a footprint model. The results demonstrate the value of scintillometry for integrating surface heterogeneity and offer improved understanding of the influence of anthropogenic materials on surface-atmosphere interactions.
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By the mid-1930s the major Hollywood studios had developed extensive networks of distribution subsidiaries across five continents. This article focuses on the operation of American film distributors in Australia – one of Hollywood's largest foreign markets. Drawing on two unique primary datasets, the article compares and investigates film distribution in Sydney's first-run and suburban-run markets. It finds that the subsidiaries of US film companies faced a greater liability of foreignness in the city centre market than in the suburban one. Our data support the argument that film audiences in local or suburban cinema markets were more receptive to Hollywood entertainment than those in metropolitan centres.
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The Weather Research and Forecasting model was applied to analyze variations in the planetary boundary layer (PBL) structure over Southeast England including central and suburban London. The parameterizations and predictive skills of two nonlocal mixing PBL schemes, YSU and ACM2, and two local mixing PBL schemes, MYJ and MYNN2, were evaluated over a variety of stability conditions, with model predictions at a 3 km grid spacing. The PBL height predictions, which are critical for scaling turbulence and diffusion in meteorological and air quality models, show significant intra-scheme variance (> 20%), and the reasons are presented. ACM2 diagnoses the PBL height thermodynamically using the bulk Richardson number method, which leads to a good agreement with the lidar data for both unstable and stable conditions. The modeled vertical profiles in the PBL, such as wind speed, turbulent kinetic energy (TKE), and heat flux, exhibit large spreads across the PBL schemes. The TKE predicted by MYJ were found to be too small and show much less diurnal variation as compared with observations over London. MYNN2 produces better TKE predictions at low levels than MYJ, but its turbulent length scale increases with height in the upper part of the strongly convective PBL, where it should decrease. The local PBL schemes considerably underestimate the entrainment heat fluxes for convective cases. The nonlocal PBL schemes exhibit stronger mixing in the mean wind fields under convective conditions than the local PBL schemes and agree better with large-eddy simulation (LES) studies.
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Site-specific meteorological forcing appropriate for applications such as urban outdoor thermal comfort simulations can be obtained using a newly coupled scheme that combines a simple slab convective boundary layer (CBL) model and urban land surface model (ULSM) (here two ULSMs are considered). The former simulates daytime CBL height, air temperature and humidity, and the latter estimates urban surface energy and water balance fluxes accounting for changes in land surface cover. The coupled models are tested at a suburban site and two rural sites, one irrigated and one unirrigated grass, in Sacramento, U.S.A. All the variables modelled compare well to measurements (e.g. coefficient of determination = 0.97 and root mean square error = 1.5 °C for air temperature). The current version is applicable to daytime conditions and needs initial state conditions for the CBL model in the appropriate range to obtain the required performance. The coupled model allows routine observations from distant sites (e.g. rural, airport) to be used to predict air temperature and relative humidity in an urban area of interest. This simple model, which can be rapidly applied, could provide urban data for applications such as air quality forecasting and building energy modelling, in addition to outdoor thermal comfort.
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The performance of three urban land surface models, run in offline mode, with their default external parameters, is evaluated for two distinctly different sites in Helsinki: Torni and Kumpula. The former is a dense city centre site with 22% vegetation, while the latter is a suburban site with over 50% vegetation. At both locations the models are compared against sensible and latent heat fluxes measured using the eddy covariance technique, along with snow depth observations. The cold climate experienced by the city causes strong seasonal variations that include snow cover and stable atmospheric conditions. Most of the time the three models are able to account for the differences between the study areas as well as the seasonal and diurnal variability of the energy balance components. However, the performances are not systematic across the modelled components, season and surface type. The net all-wave radiation is well simulated, with the greatest uncertainties related to snowmelt timing, when the fraction of snow cover has a key role, particularly in determining the surface albedo. For the turbulent fluxes, more variation between the models is seen which can partly be explained by the different methods in their calculation and partly by surface parameter values. For the sensible heat flux, simulation of wintertime values was the main problem, which also leads to issues in predicting near-surface stabilities particularly at the dense city centre site. All models have the most difficulties in simulating latent heat flux. This study particularly emphasizes that improvements are needed in the parameterization of anthropogenic heat flux and thermal parameters in winter, snow cover in spring and evapotranspiration in order to improve the surface energy balance modelling in cold climate cities.
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The Surface Urban Energy and Water Balance Scheme (SUEWS) is evaluated at two locations in the UK: a dense urban site in the centre of London and a residential suburban site in Swindon. Eddy covariance observations of the turbulent fluxes are used to assess model performance over a twoyear period (2011-2013). The distinct characteristics of the sites mean their surface energy exchanges differ considerably. The model suggests the largest differences can be attributed to surface cover (notably the proportion of vegetated versus impervious area) and the additional energy supplied by human activities. SUEWS performs better in summer than winter, and better at the suburban site than the dense urban site. One reason for this is the bias towards suburban summer field campaigns in observational data used to parameterise this (and other) model(s). The suitability of model parameters (such as albedo, energy use and water use) for the UK sites is considered and, where appropriate, alternative values are suggested. An alternative parameterisation for the surface conductance is implemented, which permits greater soil moisture deficits before evaporation is restricted at non-irrigated sites. Accounting for seasonal variation in the estimation of storage heat flux is necessary to obtain realistic wintertime fluxes.
Resumo:
Many contaminants are currently unregulated by the government and do not have a set limit, known as the Maximum Contaminant Level, which is dictated by cost and the best available treatment technology. The Maximum Contaminant Level Goal, on the other hand, is based solely upon health considerations and is non-enforceable. In addition to being naturally occurring, contaminants may enter drinking water supplies through industrial sources, agricultural practices, urban pollution, sprawl, and water treatment byproducts. Exposure to these contaminants is not limited to ingestion and can also occur through dermal absorption and inhalation in the shower. Health risks for the general public include skin damage, increased risk of cancer, circulatory problems, and multiple toxicities. At low levels, these contaminants generally are not harmful in our drinking water. However, children, pregnant women, and people with compromised immune systems are more vulnerable to the health risks associated with these contaminants. Vulnerable peoples should take additional precautions with drinking water. This research project was conducted in order to learn more about our local drinking water and to characterize our exposure to contaminants. We hope to increase public awareness of water quality issues by educating the local residents about their drinking water in order to promote public health and minimize exposure to some of the contaminants contained within public water supplies.
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Urban sprawl is a significant issue in the United States, one effect of which is the departure of the wealth from cities. This study examined the distribution of wealth in Erie County, New York, focused around Buffalo. The question is then raised, why do those with the money leave the city, and to where do they go? While this study does not attempt to explain all of the reasons, it does examine two significant issues: quality of public school education, and proximity to main highways with easy access to the city. Using ArcGIS, I was able to place the public high schools and their relative ranking over a distribution of per capita income. The results of this analysis show that the wealthiest areas are located within the best school districts. Moreover, the areas where the wealth accumulates are directly connected by major highways.
Resumo:
The empirical evaluation of the effect of land property rights typically suffers from selection problems. The allocation of property rights across households is usually not random but based on wealth, family characteristics, political clientelism, or other mechanisms built on differences between the groups that acquire property rights and the groups that do not. In this paper, we address this selection concern exploiting a natural experiment in the allocation of property rights. Twenty years ago, a homogenous group of squatters occupied a piece of privately owned land in a suburban area of Buenos Aires, Argentina. When the Congress passed an expropriation law transferring the land from the former owners to the squatters, some of the former owners surrendered the land (and received a compensation), while others decide to sue in the slow Argentine courts. These different decisions by the former owners generated an allocation of property rights that is exogenous to the characteristics of the squatters. We take advantage of this natural experiment to evaluate the effect of the allocation of urban land property rights. Our preliminary results show significant effects on housing investment, household size, and school attrition. Contradicting De Soto's hypotheses, we found nonsignificant effects on labor income and access to credit markets.
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The career of civil engineer Henrique de Novaes, a remarkable figure in the academic, technical and political fields, demonstrates its extensive and relevant work across Brazil in the first half of the twentieth century. It covered from the design of water supply and sewage works, road and rail transport networks, works against drought in the Northeast, hydroelectric and harbor facilities to the urbanization planning and architectural projects, which displays a systematic and multiple production. City and territory conformed to his fields of verification, practical and above all, transformation. The search for understanding of the inclusion of a social actor in this process thus contributes to the specific analysis of the doings of Henrique de Novaes, who graduated at Polytechnic School of Rio de Janeiro in 1906. From a polymorphic activity in different scales, one tries to figure how, through academic education or professional practice, urban history in Brazil can be told or built. The introduction of technological innovations matched the purposes of planning and urban sprawl, as well as met the specifications of regulation and institutionalization of public infrastructure services at the time. The overall plans proposed by the engineer thought of the city as a whole, interconnected to the structural networks. At the same time, the knowledge of a larger physical scale the territory bounces back in the urban in a relationship of reciprocity and completeness. The objective research, therefore, tries to understand the roles played by Henrique de Novaes s works and academic education in the accomplishment of systematic modernization of Brazilian urban space and territory, recovering a little known historical figure by current historiography. It is proposed, as methodological axis, that the study of this professional career configures itself as an essential element for understanding the idea of progress embodied in the technical studies and proposals for improvements and sanitation nationwide in the first half of the twentieth century . The primary sources for the construction of this analysis were technical articles in journals of the period ( Clube de Engenharia , Viação e Revista Brasileira de Engenharia ), and technical reports, government messages, newspaper articles published at the time, autobiographical reports and the engineer s verbal communications with relatives. The work is structured in three chapters: "Biographical traces, academic education and 'technical and political' activities" illustrates the initiation into the technical, public and political environment; Chapter 2, "Technique and territory" outlines his network understanding through sanitation and transport services; Chapter 3 "Technique and City" describes the influence of polytechnics knowledge on the propositions of modernization of cities; Finally, "Final Thoughts: An Evaluation," presents an overview of the affiliations and practice of an engineer in the different scales, and its contribution to the modernization of Brazilian urban and territorial space
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It is an ethnographic work that has an objective of verifying devices throngh the residents of a low income suburban area, and the way they deal with their social relations through sonsumerism (and the aspiration connected to it), the symbolic character acquired through consumer goods, understood as one of the fundamental components for the comprehension of the web as relations that established, Though consumerism, individuais will reveal ways of communication, of the status, of creating new forms of action and identification. Using the principal that believes in a web of symbolic significance where own individuais develop their impressions, as a resource to look at their own bodies, a social order (yet unstable), and the process of inclusion in a broader society. In conclusion, the act of consuming is more than a perspective that establishes statistics on consumer goods, with their ways of production, circulation and economic functioning: it is also a way of perceiving a collection mapped by consumers individually and socially, and by those means organizing, classifying and identifyring the social world
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In this dissertation new models of propagation path loss predictions are proposed by from techniques of optimization recent and measures of power levels for the urban and suburban areas of Natal, city of Brazilian northeast. These new proposed models are: (i) a statistical model that was implemented based in the addition of second-order statistics for the power and the altimetry of the relief in model of linear losses; (ii) a artificial neural networks model used the training of the algorithm backpropagation, in order to get the equation of propagation losses; (iii) a model based on the technique of the random walker, that considers the random of the absorption and the chaos of the environment and than its unknown parameters for the equation of propagation losses are determined through of a neural network. The digitalization of the relief for the urban and suburban areas of Natal were carried through of the development of specific computational programs and had been used available maps in the Statistics and Geography Brazilian Institute. The validations of the proposed propagation models had been carried through comparisons with measures and propagation classic models, and numerical good agreements were observed. These new considered models could be applied to any urban and suburban scenes with characteristic similar architectural to the city of Natal