914 resultados para Trees in cities


Relevância:

80.00% 80.00%

Publicador:

Resumo:

In the process of urbanization, natural and semi-natural landscapes are increasingly cherished as open space and recreational resource. Urban rivers are part of this kind of resource and thus play an important role in managing urban resilience and health. Employing the example of Tianjin, this doctoral dissertation research aims at learning to understand how to plan and design for the interface zones between urban water courses and for the land areas adjacent to such water courses. This research also aims at learning how to link waterfront space with other urban space in order to make a recreational space system for the benefit of people. Five questions of this dissertation are: 1) what is the role of rivers in spatial and open space planning? 2) What are the human needs regarding outdoor open space? 3) How do river and water front spatial structures affect people's recreational activities? 4) How to define the recreational service of urban river and waterfront open space? 5) How might answering these question change planning and design of urban open space? Quantitative and qualitative empirical approaches were combined in this study for which literature review and theoretical explorations provide the basis. Empirical investigations were conducted in the city of Tianjin. The quantitative approach includes conducting 267 quantitative interviews, and the qualitative approach includes carrying out field observations and mappings. GIS served to support analysis and visualization of empirical information that was generated through this study. By responding to the five research questions, findings and lessons include the following: 1) In the course of time rivers have gained importance in all levels and scales of spatial planning and decision making. Regarding the development of ecological networks, mainly at national scale, rivers are considered significant linear elements. Regarding regional and comprehensive development, river basins and watersheds are often considered as the structural link for strategic ecological, economic, social and recreational planning. For purposes of urban planning, particularly regarding recreational services in cities, the distribution of urban open spaces often follows the structure of river systems. 2) For the purpose of classifying human recreational needs that relate to outdoor open space Maslow's hierarchy of human needs serves as theoretical basis. The classes include geographical, safety, physiological, social and aesthetic need. These classes serve as references while analyzing river and waterfront open space and other kinds of open space. 3) Regarding the question how river and waterfront spatial structures might affect people's recreational activities, eight different landscape units were identified and compared in the case study area. Considering the thermal conditions of Tianjin, one of these landscape units was identified as affording the optimal spatial arrangement which mostly meets recreational needs. The size and the shape of open space, and the plants present in an open space have been observed as being most relevant regarding recreational activities. 4) Regarding the recreational service of urban river and waterfront open space the results of this research suggest that the recreational service is felt less intensively as the distances between water 183 front and open space user’s places of residence are increasing. As a method for estimating this ‘Service Distance Effect’ the following formula may be used: Y = a*ebx. In this equation Y means the ‘Service Distance’ between homes and open space, and X means the percentage of the people who live within this service distance. Coefficient "a" represents the distance of the residential area nearest to the water front. The coefficient "b" is a comprehensive capability index that refers to the size of the available and suitable recreational area. 5) Answers found to the questions above have implications for the planning and design of urban open space. The results from the quantitative study of recreational services of waterfront open space were applied to the assessment of river-based open space systems. It is recommended that such assessments might be done employing the network analysis function available with any GIS. In addition, several practical planning and designing suggestions are made that would help remedy any insufficient base for satisfying recreational needs. The understanding of recreational need is considered helpful for the proposing planning and designing ideas and for the changing of urban landscapes. In the course of time Tianjin's urban water system has shrunk considerably. At the same time rivers and water courses have shaped Tianjin's urban structure in noticeable ways. In the process of urbanization water has become increasingly important to the citizens and their everyday recreations. Much needs to be changed in order to improve recreational opportunities and to better provide for a livable city, most importantly when considering the increasing number of old people. Suggestions made that are based on results of this study, might be implemented in Tianjin. They are 1) to promote the quality of the waterfront open space and to make all linear waterfront area accessible recreational spaces. Then, 2), it is advisable to advocate the concept of green streets and to combine green streets with river open space in order to form an everyday recreational network. And 3) any sound urban everyday recreational service made cannot rely on only urban rivers; the whole urban structure needs to be improved, including adding small open space and optimize the form of urban communities, finally producing a multi-functional urban recreational network.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Perennial plants are the main pollen and nectar sources for bees in the tropical areas where most of the annual flora are burned in dry seasons. Therefore perennial plants constitute the most reliable bio materials for determining and evaluating the beekeeping regions of the Republic of Benin. A silvo-melliferous region (S-MR) is a geographical area characterised by a particular set of homogenous melliferous plants that can produce timber. Using both the prevailing climatic and the agro-ecological conditions six S-MRs could be identified, i.e. the South region, the Common Central region, the Central West region, the Central North region, the Middle North region and the Extreme North region. At the country level, the melliferous plants were dominated by Vitellaria paradoxa which is common to all regions. The most diversified family was the Caesalpiniaceae (12 species) followed by the Combretaceae (10 species) and Combretum being the richest genus. The effect of dominance is particularly high in the South region where Elaeis guineensis alone represented 72.6% of the tree density and 140% of the total plant importance. The total melliferous plant density varied from 99.3 plants ha^(−1) in the Common Central region to 178.0 plants ha^(−1) in the Central West region. On the basis of nectar and pollen source, the best region for beekeeping is the CentralWest region with 46.7% of nectar producing trees, 9.4% of pollen producing trees and 40.6% of plants that issue both, this in opposition to the South region which was characterised by an unbalanced distribution of melliferous trees.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

La liberalización colombiana es analizada, con frecuencia, con los coeficientes de apertura, este documento, en cambio, presenta un análisis complementario a través de algoritmos usados en la teoría de redes para caracterizar sistemas complejos. Esta nueva aproximación devela estructuras de la red mundial de comercio antes y después de la apertura, así como cambios en la posición colombiana.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Después de la llegada de las grandes superficies, los supermercados familiares y tradicionales, han visto comprometida su perdurabilidad en el mediano plazo, debido al deterioro en las ventas y la falta de inversión en capital de trabajo, desmejorando así su productividad y competitividad Se tomara como objeto de estudio un almacén de ventas al por menor “Supermercado Kompremos”, ubicado en la ciudad de Girardot , el cual ha sido el claro reflejo del impacto de las grandes superficies en las ciudades intermedias con baja población. La investigación busca reconocer la posición actual de la empresa en el mercado, la capacidad de esta para seguir compitiendo y generar valor a sus clientes externos e internos, para continuar en el sector sin deteriorarse. Para este estudio se utilizo el modelo matricial, el cual analiza el entorno de la compañía y la situación interna con el fin de interrelacionarlos, para definir una posición estratégica en el mercado, generando como resultado una estrategia de fusión, que permitan mejorar la situación competitiva de la empresa, hasta al punto de lograr perdurabilidad.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

La siguiente reflexión sobre el disfrute del derecho a la ciudad de las mujeres y de todos sus derechos humanos en los contextos urbanos se realiza a partir de las dimensiones propuestas por el enfoque de seguridad humana, en las cuales se establecen los mínimos que requieren las mujeres para gozar de una vida urbana renovada y superar las limitaciones existentes en la ciudad como espacio no neutral, que produce y reproduce inequidades entre hombres y mujeres, donde se feminiza la pobreza y se exterioriza la violencia basada en género. En este sentido, este artículo de reflexión, en el cual se presentan los resultados de la investigación “El derecho a la ciudad de las mujeres: una mirada a su goce y reconocimiento en la ciudad de Cartagena de Indias”, retoma algunas ideas propuestas por el movimiento feminista y plasmadas en las Cartas del Derecho a la Ciudad, las cuales son leídas desde la definición hecha sobre derecho a la ciudad de las mujeres y las dimensiones de la seguridad humana, resaltando en ambas su carácter integrador, indivisible y necesario, para dejar a un lado las estructuras androcéntricas y patriarcales sobre la seguridad, la democracia y la ciudadanía.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

En este estudio se realizó un análisis predictivo de la aparición de eventos adversos de los pacientes de una IPS de Bogotá, Mederi Hospital Universitario de Barrios Unidos (HUBU) durante el año 2013; relacionados con los indicadores de eficiencia hospitalaria (Porcentaje de ocupación hospitalaria, número de egresos hospitalarios, promedio de estancia hospitalaria, número de egresos de urgencias, promedio de estancia en urgencias). Los datos fueron exportados a una matriz de análisis de las variables cualitativas; fueron presentadas con frecuencias absolutas y relativas, las variables cuantitativas (edad, tiempos de estancia) fueron presentadas con media, desviaciones estándar. Se agruparon los datos de eventos adversos y de eficiencia hospitalaria en una nueva matriz que permitiera el análisis predictivo la nueva matriz fue exportada al software de modelación estadístico Eviews 6.5; se especificaron modelos predictivos multivariados para la variable número de eventos adversos, respecto de los indicadores de eficiencia hospitalaria y se estimaron las probabilidades de ocurrencia, análisis de correlación y multicolinealidad; los resultados se presentaron en tablas de estimación para cada modelo, se restringieron los eventos adversos prevenibles y no prevenibles información obtenida a través de un sistema de información que registra los factores relacionados con la ocurrencia de eventos adversos en salud, a través del sistema de reporte de eventos en salud, reporte en las historias clínicas, reporte individual, reporte por servicio, análisis de datos y estudios de caso, de la misma forma fueron extraídos los datos de eficiencia hospitalaria para el mismo periodo. El análisis y gestión de eventos adversos pretende establecer estrategias de mejoramiento continuo y análisis de resultados frente a los indicadores de eficiencia que permitan intervención de los factores de riesgo operativo de los servicios del Hospital Universitario de Barrios Unidos (HUBU), relacionados con eventos adversos en la atención de los pacientes en especial se debe enfocar en la gestión de los egresos de pacientes de acuerdo a los resultados obtenidos con el fin de alinearse y fortalecer las políticas de seguridad del paciente para brindar una atención integral con calidad y eficiencia, disminuyendo las quejas en la atención, las glosas, los riesgos jurídicos, de acuerdo al modelo predictivo estudiado.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We document the existence of a Crime Kuznets Curve in US states since the 1970s. As income levels have risen, crime has followed an inverted U-shaped pattern, first increasing and then dropping. The Crime Kuznets Curve is not explained by income inequality. In fact, we show that during the sample period inequality has risen monotonically with income, ruling out the traditional Kuznets Curve. Our finding is robust to adding a large set of controls that are used in the literature to explain the incidence of crime, as well as to controlling for state and year fixed effects. The Curve is also revealed in nonparametric specifications. The Crime Kuznets Curve exists for property crime and for some categories of violent crime.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Los principales aeropuertos del mundo han cambiado radicalmente su vocación de simples máquinas de transporte aéreo para integrarse a los territorios y ser ejes de engranajes productivos, que impulsan la economía de las ciudades contemporáneas. En ese sentido, la presente investigación busca examinar cómo ha sido el modelo de planificación desarrollado para el Aeropuerto Internacional El Dorado (AIED) y cuál es el rol que juega su entorno inmediato en dicho modelo. ¿Se ha concebido el AIED como un espacio físico que cohesiona el territorio y cataliza encadenamientos productivos y actividades económicas supraregionales? Este trabajo de grado intentará demostrar a través de un análisis cualitativo y cuantitativo, que a diferencia de las tendencias globales, el modelo de planificación del AIED aún se basa en la visión tradicional y sectorial, lo que genera un impacto económico negativo en el desarrollo económico de la ciudad de Bogotá y su área metropolitana.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In November 2008, Colombian authorities dismantled a network of Ponzi schemes, making hundreds of thousands of investors lose tens of millions of dollars throughout the country. Using original data on the geographical incidence of the Ponzi schemes, this paper estimates the impact of their break down on crime. We find that the crash of Ponzi schemes differentially exacerbated crime in affected districts. Confirming the intuition of the standard economic model of crime, this effect is only present in places with relatively weak judicial and law enforcement institutions, and with little access to consumption smoothing mechanisms such as microcredit. In addition, we show that, with the exception of economically-motivated felonies such as robbery, violent crime is not affected by the negative shock.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Los servicios de extinción de incendios en las ciudades se ven obligados a realizar su tarea cada vez con mayor rapidez y eficiencia, pero sin que exista a menudo un equilibrio entre el aumento de las exigencias en su trabajo y el correspondiente incremento de los recursos tanto materiales como humanos. Por eso se hace cada vez más imprescindible contar con nuevas técnicas y herramientas que faciliten su labor, permitiéndoles mejorar sus prestaciones con los mismos recursos. Una de las herramientas emergentes que puede ayudar a los servicios de extinción de incendios a optimizar su funcionamiento son los Sistemas de Información Geográfica (SIG). En este artículo se presentan los trabajos desarrollados hasta el momento por los autores para construir una herramienta informática basada en la tecnología SIG que pueda ser utilizada por los servicios de extinción de incendios tanto para prevenirlos como para responder de manera más rápida, eficaz y económica ante una emergencia por incendio en una vivienda o edificio. La herramienta desarrollada está orientada fundamentalmente al análisis de la distribución espacio-temporal de los incendios, con el objetivo de determinar los puntos calientes, esto es, aquellos lugares y/o momentos en los que existe una concentración atípica de incendios en el espacio y/o en el tiempo. Dicha herramienta ha sido desarrollada utilizando como base los programas gvSIG y R, ambos de acceso libre. El primero proporciona la funcionalidad de los SIG para trabajar con información geográfica, mientras que del segundo se aprovecha su capacidad para realizar análisis estadísticos. El sistema desarrollado se está utilizando para estudiar puntos calientes de incendios ocurridos en el municipio de Vigo entre los años 2005 y 2008

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Esta dissertação é muito mais do que um trabalho sobre ajardinamento de edifícios, pois pretende-se que seja uma ferramenta de ajuda em benefício da transformação de milhares de metros quadrados, das coberturas e das fachadas, muitas vezes negligenciados, em espaços verdes públicos beneficiando, não somente, os promotores imobiliários mas, acima de tudo os seus ocupantes e usufrutuários, que desta forma podem tirar partido de novos espaços de estar, ao ar livre. Enquanto a cidade, ao nível térreo, apresenta um aumento de tráfego rodoviário, com inegável poluição e confusão, é possível, desta forma, usufruir de um espaço aberto. Esta dissertação procura estudar os edifícios que já integram o elemento vegetal no seu conceito e que sejam um sucesso na forma como usam o elemento vegetal, de modo a divulgar as técnicas de construção, entender as decisões dos projectistas e o impacto nos utilizadores que habitam e usufruem dos espaços – Análise-Pós-Ocupação. Esta dissertação pretende demonstrar o quanto é importante que as cidades apresentem espaços verdes para uso da população. As zonas verdes existentes nas cidades são inequivocamente um importante indicador da qualidade ambiental existente nessas mesmas cidades. As coberturas e fachadas verdes arrefecem os edifícios, capturam e filtram as águas da chuva, proporcionam habitat à vida selvagem, reduzem o efeito de estufa das cidades, proporcionam uma preciosidade estética, uma experiência recreativa e por vezes comida, para os habitantes das cidades. Pretende-se assim, focar os benefícios humanos, sociais e naturais que se obtêm ao introduzir vegetação nas paredes, terraços, pátios e coberturas dos edifícios. Assim foi considerado útil usar uma metodologia para também analisar o tipo de espécies usadas nos estudos de caso, e determinar a necessidade de uma ferramenta para que a selecção vegetal respeite critérios de biodiversidade e melhor adaptabilidade aos ecossistemas locais, sabendo de antemão que não podem nem pretendem substituir os habitats naturais, que as cidades também podem e devem apresentar.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

1. The spatial and temporal abundance of the aphid Euceraphis betulae was investigated in relation to heterogeneity in host plant ( Betula pendula) vigour and pathogenic stress. The performance of aphids feeding on vigorous and stressed foliage was also examined. 2. The plant stress and plant vigour hypotheses have been suggested as opposing ways in which foliage quality influences herbivore abundance. In many plants, however, vigorous growing foliage co-exists with stressed or damaged foliage. 3. There was a negative correlation between branch growth ( vigour) and branch stress ( leaf chlorosis), with the most vigorous branches displaying little or no stress, and the most stressed branches achieving poor growth. There was a similar negative correlation between vigour and stress at the level of individual trees, which themselves represented a continuum in quality. 4. At the beginning of the season, E. betulae were intermittently more abundant on vigorous branches than on branches destined to become stressed, but aphids became significantly more abundant on stressed branches later in the season, when symptoms of stress became apparent. Similar patterns of aphid abundance were seen on vigorous and stressed trees in the following year. 5. Euceraphis betulae performance was generally enhanced when feeding on naturally stressed B. pendula leaves, but there was some evidence for elevated potential reproduction when feeding on vigorous leaves too. 6. Overall, plant stress probably influences E. betulae distribution more than plant vigour, but the temporal and spatial variability in plant quality suggests that plant vigour could play a role in aphid distribution early in the season.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Background If biofuels are to be a viable substitute for fossil fuels, it is essential that they retain their potential to mitigate climate change under future atmospheric conditions. Elevated atmospheric CO2 concentration [CO2] stimulates plant biomass production; however, the beneficial effects of increased production may be offset by higher energy costs in crop management. Methodology/Main findings We maintained full size poplar short rotation coppice (SRC) systems under both current ambient and future elevated [CO2] (550 ppm) and estimated their net energy and greenhouse gas balance. We show that a poplar SRC system is energy efficient and produces more energy than required for coppice management. Even more, elevated [CO2] will increase the net energy production and greenhouse gas balance of a SRC system with 18%. Managing the trees in shorter rotation cycles (i.e. 2 year cycles instead of 3 year cycles) will further enhance the benefits from elevated [CO2] on both the net energy and greenhouse gas balance. Conclusions/significance Adapting coppice management to the future atmospheric [CO2] is necessary to fully benefit from the climate mitigation potential of bio-energy systems. Further, a future increase in potential biomass production due to elevated [CO2] outweighs the increased production costs resulting in a northward extension of the area where SRC is greenhouse gas neutral. Currently, the main part of the European terrestrial carbon sink is found in forest biomass and attributed to harvesting less than the annual growth in wood. Because SRC is intensively managed, with a higher turnover in wood production than conventional forest, northward expansion of SRC is likely to erode the European terrestrial carbon sink.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

K-Means is a popular clustering algorithm which adopts an iterative refinement procedure to determine data partitions and to compute their associated centres of mass, called centroids. The straightforward implementation of the algorithm is often referred to as `brute force' since it computes a proximity measure from each data point to each centroid at every iteration of the K-Means process. Efficient implementations of the K-Means algorithm have been predominantly based on multi-dimensional binary search trees (KD-Trees). A combination of an efficient data structure and geometrical constraints allow to reduce the number of distance computations required at each iteration. In this work we present a general space partitioning approach for improving the efficiency and the scalability of the K-Means algorithm. We propose to adopt approximate hierarchical clustering methods to generate binary space partitioning trees in contrast to KD-Trees. In the experimental analysis, we have tested the performance of the proposed Binary Space Partitioning K-Means (BSP-KM) when a divisive clustering algorithm is used. We have carried out extensive experimental tests to compare the proposed approach to the one based on KD-Trees (KD-KM) in a wide range of the parameters space. BSP-KM is more scalable than KDKM, while keeping the deterministic nature of the `brute force' algorithm. In particular, the proposed space partitioning approach has shown to overcome the well-known limitation of KD-Trees in high-dimensional spaces and can also be adopted to improve the efficiency of other algorithms in which KD-Trees have been used.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

High quality wind measurements in cities are needed for numerous applications including wind engineering. Such data-sets are rare and measurement platforms may not be optimal for meteorological observations. Two years' wind data were collected on the BT Tower, London, UK, showing an upward deflection on average for all wind directions. Wind tunnel simulations were performed to investigate flow distortion around two scale models of the Tower. Using a 1:160 scale model it was shown that the Tower causes a small deflection (ca. 0.5°) compared to the lattice on top on which the instruments were placed (ca. 0–4°). These deflections may have been underestimated due to wind tunnel blockage. Using a 1:40 model, the observed flow pattern was consistent with streamwise vortex pairs shed from the upstream lattice edge. Correction factors were derived for different wind directions and reduced deflection in the full-scale data-set by <3°. Instrumental tilt caused a sinusoidal variation in deflection of ca. 2°. The residual deflection (ca. 3°) was attributed to the Tower itself. Correction of the wind-speeds was small (average 1%) therefore it was deduced that flow distortion does not significantly affect the measured wind-speeds and the wind climate statistics are reliable.