Spatio-temporal variations of ozone and nitrogen dioxide concentrations under urban trees and in a nearby open area

The evergreen Quercus ilex L. is one of the most common trees in Italian urban environments and is considered effective in the uptake of particulate and gaseous atmospheric pollutants. However, the few available estimates on O3 and NO2 removal by urban Q. ilex originate from model-based studies (which indicate NO2/O3 removal capacity of Q. ilex) and not from direct measurements of air pollutant concentrations. Thus, in the urban area of Siena (central Italy) we began long-term monitoring of O3/NO2 concentrations using passive samplers at a distance of 1, 5, 10 m from a busy road, under the canopies of Q. ilex and in a nearby open-field. Measurements performed in the period June 2011-October 2013 showed always a greater decrease of NO2 concentrations under the Q. ilex canopy than in the open-field transect. Conversely, a decrease of average O3 concentrations under the tree canopy was found only in autumn after the typical Mediterranean post-summer rainfalls. Our results indicate that interactions between O3/NO2 concentrations and trees in Mediterranean urban ecosystems are affected by temporal variations in climatic conditions. We argue therefore that the direct measurement of atmospheric pollutant concentrations should be chosen to describe local changes of aerial pollution.

Quantification of particle emission characteristics and development of an emission model for use in transport microenvironments affected by traffic emissions

Vehicle emitted particles are of significant concern based on their potential to influence local air quality and human health. Transport microenvironments usually contain higher vehicle emission concentrations compared to other environments, and people spend a substantial amount of time in these microenvironments when commuting. Currently there is limited scientific knowledge on particle concentration, passenger exposure and the distribution of vehicle emissions in transport microenvironments, partially due to the fact that the instrumentation required to conduct such measurements is not available in many research centres. Information on passenger waiting time and location in such microenvironments has also not been investigated, which makes it difficult to evaluate a passenger’s spatial-temporal exposure to vehicle emissions. Furthermore, current emission models are incapable of rapidly predicting emission distribution, given the complexity of variations in emission rates that result from changes in driving conditions, as well as the time spent in driving condition within the transport microenvironment. In order to address these scientific gaps in knowledge, this work conducted, for the first time, a comprehensive statistical analysis of experimental data, along with multi-parameter assessment, exposure evaluation and comparison, and emission model development and application, in relation to traffic interrupted transport microenvironments. The work aimed to quantify and characterise particle emissions and human exposure in the transport microenvironments, with bus stations and a pedestrian crossing identified as suitable research locations representing a typical transport microenvironment. Firstly, two bus stations in Brisbane, Australia, with different designs, were selected to conduct measurements of particle number size distributions, particle number and PM2.5 concentrations during two different seasons. Simultaneous traffic and meteorological parameters were also monitored, aiming to quantify particle characteristics and investigate the impact of bus flow rate, station design and meteorological conditions on particle characteristics at stations. The results showed higher concentrations of PN20-30 at the station situated in an open area (open station), which is likely to be attributed to the lower average daily temperature compared to the station with a canyon structure (canyon station). During precipitation events, it was found that particle number concentration in the size range 25-250 nm decreased greatly, and that the average daily reduction in PM2.5 concentration on rainy days compared to fine days was 44.2 % and 22.6 % at the open and canyon station, respectively. The effect of ambient wind speeds on particle number concentrations was also examined, and no relationship was found between particle number concentration and wind speed for the entire measurement period. In addition, 33 pairs of average half-hourly PN7-3000 concentrations were calculated and identified at the two stations, during the same time of a day, and with the same ambient wind speeds and precipitation conditions. The results of a paired t-test showed that the average half-hourly PN7-3000 concentrations at the two stations were not significantly different at the 5% confidence level (t = 0.06, p = 0.96), which indicates that the different station designs were not a crucial factor for influencing PN7-3000 concentrations. A further assessment of passenger exposure to bus emissions on a platform was evaluated at another bus station in Brisbane, Australia. The sampling was conducted over seven weekdays to investigate spatial-temporal variations in size-fractionated particle number and PM2.5 concentrations, as well as human exposure on the platform. For the whole day, the average PN13-800 concentration was 1.3 x 104 and 1.0 x 104 particle/cm3 at the centre and end of the platform, respectively, of which PN50-100 accounted for the largest proportion to the total count. Furthermore, the contribution of exposure at the bus station to the overall daily exposure was assessed using two assumed scenarios of a school student and an office worker. It was found that, although the daily time fraction (the percentage of time spend at a location in a whole day) at the station was only 0.8 %, the daily exposure fractions (the percentage of exposures at a location accounting for the daily exposure) at the station were 2.7% and 2.8 % for exposure to PN13-800 and 2.7% and 3.5% for exposure to PM2.5 for the school student and the office worker, respectively. A new parameter, “exposure intensity” (the ratio of daily exposure fraction and the daily time fraction) was also defined and calculated at the station, with values of 3.3 and 3.4 for exposure to PN13-880, and 3.3 and 4.2 for exposure to PM2.5, for the school student and the office worker, respectively. In order to quantify the enhanced emissions at critical locations and define the emission distribution in further dispersion models for traffic interrupted transport microenvironments, a composite line source emission (CLSE) model was developed to specifically quantify exposure levels and describe the spatial variability of vehicle emissions in traffic interrupted microenvironments. This model took into account the complexity of vehicle movements in the queue, as well as different emission rates relevant to various driving conditions (cruise, decelerate, idle and accelerate), and it utilised multi-representative segments to capture the accurate emission distribution for real vehicle flow. This model does not only helped to quantify the enhanced emissions at critical locations, but it also helped to define the emission source distribution of the disrupted steady flow for further dispersion modelling. The model then was applied to estimate particle number emissions at a bidirectional bus station used by diesel and compressed natural gas fuelled buses. It was found that the acceleration distance was of critical importance when estimating particle number emission, since the highest emissions occurred in sections where most of the buses were accelerating and no significant increases were observed at locations where they idled. It was also shown that emissions at the front end of the platform were 43 times greater than at the rear of the platform. The CLSE model was also applied at a signalled pedestrian crossing, in order to assess increased particle number emissions from motor vehicles when forced to stop and accelerate from rest. The CLSE model was used to calculate the total emissions produced by a specific number and mix of light petrol cars and diesel passenger buses including 1 car travelling in 1 direction (/1 direction), 14 cars / 1 direction, 1 bus / 1 direction, 28 cars / 2 directions, 24 cars and 2 buses / 2 directions, and 20 cars and 4 buses / 2 directions. It was found that the total emissions produced during stopping on a red signal were significantly higher than when the traffic moved at a steady speed. Overall, total emissions due to the interruption of the traffic increased by a factor of 13, 11, 45, 11, 41, and 43 for the above 6 cases, respectively. In summary, this PhD thesis presents the results of a comprehensive study on particle number and mass concentration, together with particle size distribution, in a bus station transport microenvironment, influenced by bus flow rates, meteorological conditions and station design. Passenger spatial-temporal exposure to bus emitted particles was also assessed according to waiting time and location along the platform, as well as the contribution of exposure at the bus station to overall daily exposure. Due to the complexity of the interrupted traffic flow within the transport microenvironments, a unique CLSE model was also developed, which is capable of quantifying emission levels at critical locations within the transport microenvironment, for the purpose of evaluating passenger exposure and conducting simulations of vehicle emission dispersion. The application of the CLSE model at a pedestrian crossing also proved its applicability and simplicity for use in a real-world transport microenvironment.

Operational semantics of aspects in business process management

Aspect orientation is an important approach to address complexity of cross-cutting concerns in Information Systems. This approach encapsulates these concerns separately and compose them to the main module when needed. Although there a different works which shows how this separation should be performed in process models, the composition of them is an open area. In this paper, we demonstrate the semantics of a service which enables this composition. The result can also be used as a blueprint to implement the service to support aspect orientation in Business Process Management area.

Sensor Data Integrity : Multi-Sensor Perception for Unmanned Ground Vehicles

This document describes large, accurately calibrated and time-synchronised datasets, gathered in controlled environmental conditions, using an unmanned ground vehicle equipped with a wide variety of sensors. These sensors include: multiple laser scanners, a millimetre wave radar scanner, a colour camera and an infra-red camera. Full details of the sensors are given, as well as the calibration parameters needed to locate them with respect to each other and to the platform. This report also specifies the format and content of the data, and the conditions in which the data have been gathered. The data collection was made in two different situations of the vehicle: static and dynamic. The static tests consisted of sensing a fixed ’reference’ terrain, containing simple known objects, from a motionless vehicle. For the dynamic tests, data were acquired from a moving vehicle in various environments, mainly rural, including an open area, a semi-urban zone and a natural area with different types of vegetation. For both categories, data have been gathered in controlled environmental conditions, which included the presence of dust, smoke and rain. Most of the environments involved were static, except for a few specific datasets which involve the presence of a walking pedestrian. Finally, this document presents illustrations of the effects of adverse environmental conditions on sensor data, as a first step towards reliability and integrity in autonomous perceptual systems.

On the measurement of the surface energy budget over a land surface during the summer monsoon

The measurement of surface energy balance over a land surface in an open area in Bangalore is reported. Measurements of all variables needed to calculate the surface energy balance on time scales longer than a week are made. Components of radiative fluxes are measured while sensible and latent heat fluxes are based on the bulk method using measurements made at two levels on a micrometeorological tower of 10 m height. The bulk flux formulation is verified by comparing its fluxes with direct fluxes using sonic anemometer data sampled at 10 Hz. Soil temperature is measured at 4 depths. Data have been continuously collected for over 6 months covering pre-monsoon and monsoon periods during the year 2006. The study first addresses the issue of getting the fluxes accurately. It is shown that water vapour measurements are the most crucial. A bias of 0.25% in relative humidity, which is well above the normal accuracy assumed the manufacturers but achievable in the field using a combination of laboratory calibration and field intercomparisons, results in about 20 W m(-2) change in the latent heat flux on the seasonal time scale. When seen on the seasonal time scale, the net longwave radiation is the largest energy loss term at the experimental site. The seasonal variation in the energy sink term is small compared to that in the energy source term.

Locus Bonus : The Relationship of the Roman Villa to its Environment in the Vicinity of Rome

The aim of this study is to examine the relationship of the Roman villa to its environment. The villa was an important feature of the countryside intended both for agricultural production and for leisure. Manuals of Roman agriculture give instructions on how to select a location for an estate. The ideal location was a moderate slope facing east or south in a healthy area and good neighborhood, near good water resources and fertile soils. A road or a navigable river or the sea was needed for transportation of produce. A market for selling the produce, a town or a village, should have been nearby. The research area is the surroundings of the city of Rome, a key area for the development of the villa. The materials used consist of archaeological settlement sites, literary and epigraphical evidence as well as environmental data. The sites include all settlement sites from the 7th century BC to 5th century AD to examine changes in the tradition of site selection. Geographical Information Systems were used to analyze the data. Six aspects of location were examined: geology, soils, water resources, terrain, visibility/viewability and relationship to roads and habitation centers. Geology was important for finding building materials and the large villas from the 2nd century BC onwards are close to sources of building stones. Fertile soils were sought even in the period of the densest settlement. The area is rich in water, both rainfall and groundwater, and finding a water supply was fairly easy. A certain kind of terrain was sought over very long periods: a small spur or ridge shoulder facing preferably south with an open area in front of the site. The most popular villa resorts are located on the slopes visible from almost the entire Roman region. A visible villa served the social and political aspirations of the owner, whereas being in the villa created a sense of privacy. The area has a very dense road network ensuring good connectivity from almost anywhere in the region. The best visibility/viewability, dense settlement and most burials by roads coincide, creating a good neighborhood. The locations featuring the most qualities cover nearly a quarter of the area and more than half of the settlement sites are located in them. The ideal location was based on centuries of practical experience and rationalized by the literary tradition.

Comunidades de anfíbios anuros em duas fitofisionomias do Parque Estadual da Serra do Tabuleiro, estado de Santa Catarina

O estado de Santa Catarina possuía sua área inteiramente coberta por Mata Atlântica, um dos biomas mais ameaçados mundialmente. Mesmo com o crescente aumento de informações sobre os anfíbios no estado, ainda existe muitas lacunas de informações para este grupo e o desconhecimento é alto mesmo no interior das Unidades de Conservação. O Parque Estadual da Serra do Tabuleiro é a maior unidade de conservação de proteção integral de Santa Catarina e ainda assim possui inúmeras ameaças e pressões antrópicas. Os objetivos deste estudo foram estudar os anfíbios anuros em duas fitofisionomias, restinga e floresta ombrófila densa submontana, do Parque Estadual da Serra do Tabuleiro, verificar as diferenças dos parâmetros da comunidade entre três mesohábitats na restinga, compreender em que extensão algumas variáveis estruturais do hábitat afetam a riqueza e abundância dos anuros na restinga e na floresta ombrófila densa submontana, conhecer os anuros de folhiço na área de floresta e, adicionalmente, verificar o atual conhecimento sobre os anuros de folhiço no mundo. Os anuros no parque foram amostrados por meio dos métodos de procura ativa em transecções, armadilhas de queda com cerca guia e parcelas no chão da floresta durante três anos consecutivos com amostragens trimestrais, de julho de 2007 a abril de 2010. As variáves estruturais foram medidas nos locais amostrados enquanto que os dados climáticos foram obtidos da estação meteorológica mais próxima da área de estudo. A revisão sobre os anuros de folhiço no mundo foi realizada por uma busca na base de dados ISI Web if Science entre os anos de 1945 e 2008. Foram registradas 39 espécies de anuros no Parque, sendo 15 espécies para a restinga, 31 espécies na floresta. No folhiço do chão da floresta, a comunidade foi composta por 13 espécies de anuros. No total, 66% dos anuros registrados aqui, foram endêmicos da Mata Atlântica, 17% possuíram distribuição restrita à Santa Catarina e quatro espécies foram consideradas como vulneráveis na lista de espécies ameaçadas de extinção de Santa Catarina. Na restinga, a área aberta e a mata de restinga foram as mais dissimilares com relação à composição e abundância de anuros e também para as variáveis estruturais do hábitat. Na floresta ombrófila densa, a cobertura de dossel e o número de corpos dágua foram as variáveis mais importantes para a riqueza e abundância das espécies de anuros. Também para os anuros de folhiço do parque, a cobertura de dossel foi importante, conjuntamente com a umidade do ar e a profundidade de folhiço. O atual conhecimento sobre os anuros de folhiço no mundo se concentra nas regiões tropicais, sendo que o Brasil possui o maior número de estudos. Algumas tendências para as comunidades de anuros de folhiço puderam ser identificadas, mas estudos adicionais são necessários para que mais inferências possam ser feitas. O presente estudo contribuiu para preencher parte das lacunas de conhecimento existentes para a biodiversidade dos anuros do estado de Santa Catarina e em especial para o Parque Estadual da Serra do Tabuleiro.

Emissão de CO2 do solo e sua correlação com a rizosfera de diferentes paisagens de áreas mineradas do município de Santo Antônio de Pádua-RJ

Objetivando avaliar o comportamento das emissões de CO2 do solo em áreas mineradas do município de Santo Antônio de Pádua-RJ e sua correlação com a rizosfera, este presente estudo utilizou uma câmara fechada com sensor de infravermelho em três diferentes paisagens, a saber: A-1 (área reflorestada há 10 anos), A-2 (área desmatada) e A-3 (área em processo de recuperação). Em cada área foi instalada três cilindros para efeitos de repetição. O monitoramento foi realizado durante os meses representativos de cada estação do ano de 2013, sendo a análise realizada durante dois dias consecutivos. Concomitantemente as coletas de CO2 foram realizadas coletas de dados de temperatura e umidade do solo, sendo também avaliadas informações pedológicas através das análises de granulometria, porosidade, pH, carbono orgânico e matéria orgânica. Informações meteorológicas e microclimatológicas também foram extraídas através de uma estação meteorológica automática e através de sensores portáteis. Os resultados permitem concluir que existe uma variação sazonal dos fluxos de CO2, havendo uma tendência de máximos de emissão durante o verão e de mínimas durante o inverno, sendo o outono e a primavera marcados por valores medianos. A correlação das áreas entre os dois dias monitoramento indicam que as emissões foram semelhantes ao da análise em dia anterior, apresentando uma correlação significativa a 5% para A-1 e A-2 e de 1% para A-3. A-1 e A-2 apresentaram emissões de CO2 mais homogêneas que A-3, havendo, entretanto, um maior fluxo de CO2 durante o verão para todas as áreas. Os dados de MOS, COS e pH demonstraram não haver uma correlação direta com as emissões de CO2. Os dados de porosidade e densidade, porém, apontam para uma possível correlação com as menores emissões de CO2 em A-3 devido a menor porosidade e maior densidade de seus solos. A temperatura do solo foi a variável que mais se correlacionou com as emissões de CO2, havendo um índice igual a r =0,68 para A-1 e de r =0,74 para A-2, sendo que em A-3 esta correlação não foi significativa. A temperatura do ar demonstrou uma correlação somente na área descampada de A-2. No que se refere à correlação da umidade do solo não houve correlações diretas significativas, sendo que somente houve uma correlação negativa (r=-0,50) significativa a 5% em A-3 com a umidade do ar. O diagnóstico ambiental das áreas de monitoramento revela que estas possuem baixos indicadores de qualidade, sendo afetados também pela escassez hídrica da região durante oito meses do ano. A-1 apresenta os melhores indicadores biológicos, químicos e microclimáticos, seguidos por A-2 e A-3 que apresentam diversas deficiências e problemas em termos de estrutura e atividade biológica dos solos. Neste estudo permite-se concluir que áreas próximas, porém com características distintas podem produzir diferentes padrões de emissão de CO2, dificultando, portanto, estimativas globais de emissão de CO2. Os elementos mais associados às emissões de CO2 parecem estar relacionados à temperatura do solo e do ar, umidade do ar e estrutura do solo, havendo, entretanto, outros fatores que podem estar indiretamente relacionados e que exercem diferentes influências de acordo com o ambiente analisado.

Composição elementar corporal, desbalanço alimentar e reciclagem de nutrientes em peixes de um riacho costeiro de Mata Atlântica

No presente estudo foi avaliada a variação na dieta e na composição elementar corporal (C:N:P) de oito espécies de peixes que coocorrem em dois trechos de um riacho. Além disso, foram investigadas as diferenças na demanda e excreção de nutrientes por duas espécies de Loricariidae, sendo uma nativa (Hypostomus punctatus) e a outra não nativa (Parotocinclus maculicauda). As coletas foram realizadas no rio Ubatiba, através de pesca elétrica em diferentes meses entre os anos de 2010 e 2012. A partir da análise alimentar, observamos que as espécies apresentaram variação na dieta entre as localidades, com exceção das duas espécies de Characidium. Apesar destas variações, o presente estudo corroborou a hipótese de homeostase estequiométrica corporal. A exceção foi a espécie Hoplias malabaricus que apresentou variação na concentração elementar corporal e alto desbalanço alimentar entre as localidades, sendo as diferenças mais acentuadas na área aberta. Analisando as diferenças na demanda nutricional dos Loricariidae verificamos uma maior concentração corporal de carbono e nitrogênio para a espécie nativa e maior de fósforo na espécie não nativa, sendo essa diferença confirmada por um maior consumo de fósforo pela espécie não nativa. A análise da excreção revelou que a espécie nativa excreta mais nitrogênio e fósforo que a não nativa. Sendo assim, os resultados sugerem que a espécie não nativa apresenta uma requisição de fósforo maior do que a nativa. Logo, ambientes com altas concentrações de nutrientes, tal como o riacho estudado, podem favorecer o estabelecimento desta espécie

Land-cover changes in an urban lake watershed in a mega-city, Central China

Urbanization can exert a profound influence on land covers and landscape characteristics. In this study, we characterize the impact of urbanization on land cover and lacustrine landscape and their consequences in a large urban lake watershed, Donghu Lake watershed (the largest urban lake in China), Central China, by using Landsat TM satellite images of three periods of 1987, 1993 and 1999 and ground-based information. We grouped the land covers into six categories: water body, vegetable land, forested land, shrub-grass land, open area and urban land, and calculated patch-related landscape indices to analyze the effects of urbanization on landscape features. We overlaid the land cover maps of the three periods to track the land cover change processes. The results indicated that urban land continuously expanded from 9.1% of the total watershed area in 1987, to 19.4% in 1993, and to 29.6% in 1999. The vegetable land increased from 7.0% in 1987, 11.9% in 1993, to 13.9% in 1999 to sustain the demands of vegetable for increased urban population. Concurrently, continuous reduction of other land cover types occurred between 1987 and 1999: water body decreased from 30.4% to 23.8%, and forested land from 33.6% to 24.3%. We found that the expansion of urban land has at least in part caused a decrease in relatively wild habitats, such as urban forest and lake water area. These alterations had resulted in significant negative environmental consequences, including decline of lakes, deterioration of water and air quality, and loss of biodiversity.

Simulating the evacuation of very large populations in large domains using a parallel implementation of the buildingEXODUS evacuation model

Computer egress simulation has potential to be used in large scale incidents to provide live advice to incident commanders. While there are many considerations which must be taken into account when applying such models to live incidents, one of the first concerns the computational speed of simulations. No matter how important the insight provided by the simulation, numerical hindsight will not prove useful to an incident commander. Thus for this type of application to be useful, it is essential that the simulation can be run many times faster than real time. Parallel processing is a method of reducing run times for very large computational simulations by distributing the workload amongst a number of CPUs. In this paper we examine the development of a parallel version of the buildingEXODUS software. The parallel strategy implemented is based on a systematic partitioning of the problem domain onto an arbitrary number of sub-domains. Each sub-domain is computed on a separate processor and runs its own copy of the EXODUS code. The software has been designed to work on typical office based networked PCs but will also function on a Windows based cluster. Two evaluation scenarios using the parallel implementation of EXODUS are described; a large open area and a 50 story high-rise building scenario. Speed-ups of up to 3.7 are achieved using up to six computers, with high-rise building evacuation simulation achieving run times of 6.4 times faster than real time.

Effet du développement résidentiel sur l'habitat et la distribution des macrophytes dans les lacs des Laurentides

L’effet du développement résidentiel des bassins versants sur l’habitat et la distribution des macrophytes dans le littoral de six lacs des Laurentides a été évalué à l’aide de carottes de sédiments et de quadrats. Le développement augmente la proportion de milieux déboisés ce qui réduit l’apport en débris de bois et augmente l’érosion et les apports de nutriments dans les sédiments du littoral. Les sédiments sont plus fins, plus denses et contiennent moins de matière organique. Ces changements favorisent les macrophytes en augmentant leur couverture dans les lacs développés. La présence d’espèces submergées de macrophytes est également favorisée au détriment des espèces à feuilles flottantes, plus caractéristiques des lacs moins développés. Même si la biomasse des macrophytes est limitée dans certains lacs, celle-ci augmente dans les lacs développés et montre des signes d’un effet tampon sur les apports de nutriments. Des quantités équivalentes à des valeurs entre 35 et 230% des apports annuels de phosphore et entre 79 et 659% des apports d’azote par les résidents ont été accumulées dans les tissus des macrophytes des lacs dont le bassin versant est très déboisé. Les sédiments s’enrichissent à la sénescence des macrophytes et contiennent alors plus de nutriments que la colonne d’eau et ce, pour tous les lacs. Une présence accrue d’espèces submergées et plus de nutriments dans les tissus des macrophytes des lacs développés, jumelés à l’absence de prolifération de phytoplancton malgré un plus grand apport de nutriments, laisse penser que les lacs des Laurentides sont en état d’eutrophisation précoce.

Von den Markenteilungen bis zum Emscher Landschaftspark: Freiraumverluste und Freiraumschutz im Ruhrgebiet

In der vorliegenden Arbeit werden die Erfolge und Misserfolge der Freiraumpolitik im Ruhrgebiet untersucht. Ausgangspunkte sind der Freiraumschwund, der über einen Zeitraum von fast 200 Jahren dokumentiert wird, sowie die Gegenbewegungen, die sich für den Freiraumschutz einsetzen. Nach der Vorstellung einer Freiraumtypologie werden diese Entwicklungen in detaillierten historischen Abrissen für jeden Freiraumtyp dargestellt, woraus sich eine eigene Ruhrgebietsgeschichte - aus der Perspektive der Freiflächen und ihrer Nutzer - ergibt. Folgerichtig beginnt die vorliegende Arbeit nicht mit Kohle und Eisen, sondern mit der Land- und Forstwirtschaft. Anhand historischer Quellen wird die gängige Am-Anfang-war-die-Heide-These widerlegt, denn das Ruhrgebiet war waldreich und ein produktiver Agrarraum. Landwirtschaftliche Flächen- und Waldverluste sind die Basis der Siedlungstätigkeit. Ohne die Gemeinheitsteilungen im 19. Jahrhundert wären die Stadterweiterungen und Industrieansiedlungen im Ruhrgebiet nicht möglich gewesen. Die - in Grundzügen im Ersten Weltkrieg entwickelte - Agrarpolitik mit der Förderung von Produktivitätssteigerungen und Hofaufgaben erleichterte den weiteren Entzug von Agrarflächen, und genauso wirkt heute die Liberalisierung der Agrarmärkte. Alternative Ansätze (z.B. Direktvermarktung) konnten diesen Trend noch nicht aufhalten. Auch das Baumschutzgesetz von 1922 konnte die nationalsozialistischen Kahlschläge, die Waldverluste im Zweiten Weltkrieg und durch den Wiederaufbau nicht verhindern. Erst seit der Deindustrialisierung, der Aufforstung von Halden und der Umweltbewegung nehmen Wälder wieder zu. Demgegenüber treten Ende des 19. Jahrhunderts völlig neue Freiraumtypen auf. Die bürgerschaftliche Kleingartenbewegung wurde dank ihrer Bedeutung für die Ernährung in den Städten seit dem Ersten Weltkrieg vom Staat stark unterstützt, von den Nationalsozialisten gleichgeschaltet, konnte aber in den 1950er Jahren ihren bürgerschaftlichen Charakter und ihre Stärke wieder zurückgewinnen. Auch wenn Kleingärten als bauliche Reserveflächen missbraucht werden, geschieht dies nicht mehr ohne Ersatzland. Im Unterschied hierzu wurde die Stadtparkbewegung kommunalisiert. Sodann entstanden Volksparks mit Sportanlagen, ästhetisch ausgerichtete Gartenschauen, die breit gefächerten Revierparks der 1970er Jahre und neue Parktypen im Emscher Landschaftspark. 1920 wird der Siedlungsverband Ruhrkohlenbezirk gegründet, der mit den Verbandsgrünflächen ein eigenes Instrument zum Freiraumschutz und die Kompetenz zur Fluchtlinien- bzw. Bebauungsplanung erhielt. Inzwischen darf der Verband, vor einigen Jahren in den Regionalverband Ruhr umgewandelt, zu kommunalen Planungen nur noch Stellungnahmen abgeben. Schon früh versuchte der Verband, industrielles Ödland zu begrünen. Nach den Bahndammbegrünungen vor dem Zweiten Weltkrieg hat er seit den 1950er Jahren Halden aufgeforstet, bis in den 1990er Jahren der Aufbau des Emscher Landschaftsparks begann. Zechen- und Industriebrachen werden in neue Parks, Halden und Mülldeponien in Landmarken und Freizeitlandschaften verwandelt. Zu fragen ist, was aus diesen Geschichten für die Freiraumpolitik folgt. Zwei gegensätzliche Thesen werden diskutiert: die Tragedy of the Commons, die im Gemeineigentum die Ursache ökologischer Probleme sieht, während der Common-Property-Ansatz gerade in gemeinschaftlichen Nutzungen einen Ansatz für Problemlösungen sieht. Dabei liegt eine Besonderheit von Freiräumen in ihrem hohen Öffentlichkeitsgrad, d.h. dass sie von vielen Menschen genutzt werden und gleichzeitig mehrere, z.B. produktive, ökologische, politische oder berufliche Funktionen erfüllen. Untersucht wird, inwieweit erfolgreich gesicherte Freiflächen Merkmale von stabilen Common-Property-Institutionen tragen, d.h. welche Funktionen die Freiräume erfüllen, wie ihre Nutzung geregelt ist und vor allem welchen Einfluss die Nutzer auf Entscheidungen haben. Thesenhaft lässt sich zusammenfassen, dass ein Teil der Freiräume sein Wachstum einer derzeit unverzichtbaren Funktion verdankt, nämlich der Camouflage von Müll und Altlasten, die eine bauliche Nutzung ausschließen. Andere Freiräume verdanken ihren Bestand ihren vielfältigen Nutzungen, zur Erholung, durch Denkmäler, für Veranstaltungen, aber auch der Wertsteigerung für umliegende Wohngebiete. Ein kleiner Teil der Freiräume hat tatsächlich einen Common-Property-Charakter: Kleingartenanlagen, die von bürgerschaftlichen Gruppen gegründeten Parks sowie die Flächen, die durch Bürgerinitiativen o.ä. gegen eine bauliche Umnutzung verteidigt werden. Grund genug, um die Idee eines Netzwerks von Parkvereinen aufzugreifen, die sich von bürgerschaftlicher Seite aus für Freiräume einsetzen können.

Como constroem os juízes a decisão de casos difíceis? R. Posner e o Direito como uma Área Aberta. Algumas reflexões

In “How Judges Think” R. Posner’s main purpose is to develop a “cogent, unified, realist and appropriately eclectic account of how judges arrive to their decisions in nonroutine cases”. Because “law” is unnable to generate acceptable answers to all legal questions there’s an open area in which judges have decisional discretion. This article focuses on that concept of “open area” and in how judges behave when they are judging in the open area.

Effect of mountain breeze in ventilating the city under calm and neutral atmospheric environment: Interaction of airflow structures and ventilation efficiency

Many modern cities locate in the mountainous areas, like Hong Kong, Phoenix City and Los Angles. It is confirmed in the literature that the mountain wind system developed by differential heating or cooling can be very beneficial in ventilating the city nearby and alleviating the UHI effect. However, the direct interaction of mountain wind with the natural-convection circulation due to heated urban surfaces has not been studied, to our best knowledge. This kind of unique interaction of two kinds of airflow structures under calm and neutral atmospheric environment is investigated in this paper by CFD approach. A physical model comprising a simple mountain and three long building blocks (forming two street canyons) is firstly developed. Different airflow structures are identified within the conditions of different mountain-building height ratios (R=Hm/Hb) by varying building height but fixing mountain height. It is found that the higher ventilation rate in the street canyons is expected in the cases of smaller mountain-building ratios, indicating the stronger natural convection due to increasing heated building surfaces. However, there is the highest air change rate (ACH) in the lowest-building-height case and most of the air is advective into the street canyon through the top open area, highlighting the important role played by the mountain wind. In terms of the ventilation efficiency, it is shown that the smallest R case enjoys the best air change efficiency followed by the highest R case, while the worst ventilative street canyons occur at the middle R case. In the end, a gap across the streets is introduced in the modeling. The existence of the gap can greatly channel the mountain wind and distribute the air into streets nearby. Thus the ACH can be doubled and air quality can be significantly improved.