882 resultados para Classification of urban environment
Resumo:
This article looks at the development of urban tourism in Havana, Cuba, in the period since the collapse of state socialism in the USSR and Eastern Europe. It provides an interesting case study of the adoption of an outward-oriented state development policy in the context of a socialist state. The dramatic rise of urban-based tourism in Havana since 1989 is described, followed by a review of the socio-economic impacts of such tourism. These include: income generation; job creation; the rise of the informal economy, including crime and prostitution; increased migration to the primary city, along with spatial concentration on the coastal strip, and associated environmental impacts. In conclusion, the article considers the fat that the promotion of tourism has returned Havana to some of the conditions that existed in the city Socialist Revolution in 1959.
Resumo:
Site-specific management requires accurate knowledge of the spatial variation in a range of soil properties within fields. This involves considerable sampling effort, which is costly. Ancillary data, such as crop yield, elevation and apparent electrical conductivity (ECa) of the soil, can provide insight into the spatial variation of some soil properties. A multivariate classification with spatial constraint imposed by the variogram was used to classify data from two arable crop fields. The yield data comprised 5 years of crop yield, and the ancillary data 3 years of yield data, elevation and ECa. Information on soil chemical and physical properties was provided by intensive surveys of the soil. Multivariate variograms computed from these data were used to constrain sites spatially within classes to increase their contiguity. The constrained classifications resulted in coherent classes, and those based on the ancillary data were similar to those from the soil properties. The ancillary data seemed to identify areas in the field where the soil is reasonably homogeneous. The results of targeted sampling showed that these classes could be used as a basis for management and to guide future sampling of the soil.
Resumo:
Public concern over impacts of chemicals in plant and animal production on health and the environment has led to increased demand for organic produce, which is usually promoted and often perceived as containing fewer contaminants, more nutrients, and being positive for the environment. These benefits are difficult to quantify, and potential environmental impacts on such benefits have not been widely studied. This book addresses these key points, examining factors such as the role of certain nutrients in prevention and promotion of chronic disease, potential health benefits of bioactive compounds in plants, the prevalence of food-borne pesticides and pathogens and how both local and global environmental factors may affect any differences between organic and conventionally produced food. This book is an essential resource for researchers and students in human health and nutrition, environmental science, agriculture and organic farming. Main Contents 1. Organic farming and food systems: definitions and key characteristics. 2. The health benefits of n-3 fatty acids and their concentrations in organic and conventional animal-derived foods. 3. Environmental impacts on n-3 content of foods from ruminant animals. 4. Health benefits and selenium content of organic vs conventional foods. 5. Environmental impacts concerning the selenium content of foods. 6. Contaminants in organic and conventional food: the missing link between contaminant levels and health effects. 7. Mycotoxins in organic and conventional foods and effects of the environment. 8. Human pathogens in organic and conventional foods and effects of the environment. 9. What does consumer science tell us about organic foods? 10. The beneficial effects of dietary flavonoids: sources, bioavailability and biological functions. 11. Environmental regulation of flavonoid biosynthesis. 12. Nitrates in the human diet. 13. Impacts of environment and management on nitrate in vegetables and water. 14. Effects of the environment on the nutritional quality and safety of organically produced foods: Round-up and summary.
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Bloom-forming and toxin-producing cyanobacteria remain a persistent nuisance across the world. Modelling of cyanobacteria in freshwaters is an important tool for understanding their population dynamics and predicting bloom occurrence in lakes and rivers. In this paper existing key models of cyanobacteria are reviewed, evaluated and classified. Two major groups emerge: deterministic mathematical and artificial neural network models. Mathematical models can be further subcategorized into those models concerned with impounded water bodies and those concerned with rivers. Most existing models focus on a single aspect such as the growth of transport mechanisms, but there are a few models which couple both.
Resumo:
Most research on the discourses and practices of urban regeneration in-the UK has examined case studies located in areas of relative socio-economic distress. Less research has been undertaken on regeneration projects and agendas in areas characterise by strong economic growth. Yet, it is in such places that some of the best examples of the discourses, practices and impacts of contemporary urban regeneration can be. found. In some areas of high demand regeneration projects have used inner urban brownfield sites as locations for new investment. With the New Labour government's urban policy agendas targeting similar forms of regeneration, an examination of completed or on-going schemes is timely and relevant to debates over the direction that policy should take. This paper, drawing on a study of urban regeneration in one of England's, fastest growing towns, Reading in Berkshire, examines the discourses, practices and impacts of redevelopment schemes during the 1990s and 2000s. Reading's experiences have received national attention and have been hailed as a model for other urban areas to follow. The research documents the discursive and concrete aspects of local regeneration and examines the ways in which specific priorities and defined problems have come to dominate agendas. Collectively, the study argues that market-driven objectives come to dominate regeneration agendas, even in areas of strong demand where development agencies wield a relatively high degree of influence. Such regeneration plays a symbolic and practical role in creating new forms of exclusion and interpretations of place. (C) 2003 Elsevier Science Ltd. All rights reserved.
Resumo:
Direct numerical simulations of turbulent flow over regular arrays of urban-like, cubical obstacles are reported. Results are analysed in terms of a formal spatial averaging procedure to enable interpretation of the flow within the arrays as a canopy flow, and of the flow above as a rough wall boundary layer. Spatial averages of the mean velocity, turbulent stresses and pressure drag are computed. The statistics compare very well with data from wind-tunnel experiments. Within the arrays the time-averaged flow structure gives rise to significant 'dispersive stress' whereas above the Reynolds stress dominates. The mean flow structure and turbulence statistics depend significantly on the layout of the cubes. Unsteady effects are important, especially in the lower canopy layer where turbulent fluctuations dominate over the mean flow.
Resumo:
In this work a new method for clustering and building a topographic representation of a bacteria taxonomy is presented. The method is based on the analysis of stable parts of the genome, the so-called “housekeeping genes”. The proposed method generates topographic maps of the bacteria taxonomy, where relations among different type strains can be visually inspected and verified. Two well known DNA alignement algorithms are applied to the genomic sequences. Topographic maps are optimized to represent the similarity among the sequences according to their evolutionary distances. The experimental analysis is carried out on 147 type strains of the Gammaprotebacteria class by means of the 16S rRNA housekeeping gene. Complete sequences of the gene have been retrieved from the NCBI public database. In the experimental tests the maps show clusters of homologous type strains and present some singular cases potentially due to incorrect classification or erroneous annotations in the database.