896 resultados para Urban vegetation management
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This paper presents MOTION, a modular on-line model for urban traffic signal control. It consists of a network and a local level and builds on enhanced traffic state estimation. Special consideration is given to the prioritization of public transit. MOTION provides possibilities for the interaction with integrated urban management systems.
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Fisheries are very important to Uganda's economy. The sector provides a vital source of food, recreation, trade and socioeconomic well being for the people and community globally. The fisheries of small lakes are important for producing fish for local populations who are not near the large lakes. These satellite lakes support important fisheries and other economic activities like fishing, water for domestic purposes and tourism, besides socio-cultural values. A number-of fish;- species, some of which were found only in Lake Victoria have been depleted through over-exploitation, introduction of exotics especiaily Nile perch and environmental degradation. Some of these fishes have been observed to survive in satellite lakes in the Victoria and Kyoga Lake basins. The Nabugabo satellite lakes (Manywa, Kayugi and Kayanja) contain endemic Cichlid fish species acting as reservoirs and therefore very important for conservation of fish biodiversity. Despite the socio-economic importance and uniqueness of these satellite lakes little research on socio-economic studies has been carried out. The sustainability of the lake is being threatened by increasing human activities. The fish stocks and species diversity are declining and this poses a threat to the livelihood of the people who depend on fish for food and income. Arising from this need a study was carried out to establish the socio-economic aspects of Nabugabo fisheries and implications for management, on which basis resource users would be made aware of the impacts of their activities. It was hoped that this would go further to ensure wise use and management of the resources by the users. The specific objectives were identifying activities around the lake, establishing socioeconomic values attached to the lake, identifying problems of the lake and resource users and examining existing local based management institutions. Results show that the activities taking place around the lakes include fishing, farming, watering of animals, deforestation and charcoal burning, brick making, resort beach development and food and refreshment. The major problem facing the lake was found to be encroachment of Hippo grass (Vossia) on the lake, which is decreasing the size of the lake, and limiting open waters for fishing (this only applied to Lake Nabugabo). Other important problems include use of illegal fishing methods, declining fish stocks and loss of cultural identity. The resource users are most pressed by the low incomes resulting from poor fish catches, theft of gears and lack of market. On examining the resource base for the lakes, it was only Lake Nabugabo that had a Landing Management Committee. The other three lakes did not have leadership institutions in place except the local councils for the respective villages. This was probably due to observed limited fisheries activities. Majority of the respondents agreed that Government and other service providers should work jointly to supplement local beach management committees in the management of the lakes resources. This is a good gesture because with increase in fishing effort and rampant use of illegal fishing methods, there is need to strengthen management institutions present on the lake. This would require Government, local community and other service providers to work together in a participatory way to control environment-degrading activities and stop the use of illegal fishing methods. Burning of vegetation on the lake should be stopped since it enhances growth of this grass. Finally, traditional taboos; which are present on some of the Nabugabo lakes, should be enhanced, as away of preserving them.
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A casual study of the hydrological map of Uganda would convince every serious fisherman and fisheater that he is most favoured to be in Uganda. The extent and distribution of the country's aquatic system plus the rich variety of fish species there is promises a fishery potential of considerable magnitude: The open waterways comprised by the Uganda portions of Lakes Victoria, Albert and Edward; and Lakes Kyoga, George plus minor lakes Wamala, Kijanebarora, mutanda, etc. occupy about 15% of the total surface area (91,000 m2; Depart. Land Survey, 1962). Most of the nation's fish supplies are currontly from this source. 1.2. A rich network of permanent and seasonal rivers and streams filling and/or emptying various water systems covers most of Uganda. This aquatic network is associated with a fish fauna whose immense significance as a source of protein is perhaps better appreciated by the local subsistance fisherman and consumer than by the fisheries scientist and manager in this country. Many species of this fish fauna have strong affinities with the open water systems while some are typically riverine. 1.3. Then there are wetlands composed mainly of expanses of swamp, but including some areas of bog. These cover about 2% of the country. While the variety of fish fauna found here is limited by the rather hostile nature of the environment (comparatively de-oxygenated under a canopy of dense stands of emergont vegetation) several specialised fishes e.g. Clarias spp. and Protpterus aethiopicus (Kamongo) occur here. Availability of permanent and seasonal sources of water, well distributed throughout most areas of Uganda, opens up immense potential for a variety of aquaculture practices. However, while active exploitation of much of these fishery resources is currently underway, important questions regarding the magnitudes of the various resource potentials and dynamics, and about suitable levels and modes of exploitation, are yet unanswered. These gaps in knowledge go about the fishery resources of Uganda would hinder formulation of adequate development and management schemes. This short paper examines some of the above problems and suggests some approaches towards balanced oxploitation and management of the fisheries of Uganda.
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Carbon and nitrogen loading to streams and rivers contributes to eutrophication as well as greenhouse gas (GHG) production in streams, rivers and estuaries. My dissertation consists of three research chapters, which examine interactions and potential trade-offs between water quality and greenhouse gas production in urban streams of the Chesapeake Bay watershed. My first research project focused on drivers of carbon export and quality in an urbanized river. I found that watershed carbon sources (soils and leaves) contributed more than in-stream production to overall carbon export, but that periods of high in-stream productivity were important over seasonal and daily timescales. My second research chapter examined the influence of urban storm-water and sanitary infrastructure on dissolved and gaseous carbon and nitrogen concentrations in headwater streams. Gases (CO2, CH4, and N2O) were consistently super-saturated throughout the course of a year. N2O concentrations in streams draining septic systems were within the high range of previously published values. Total dissolved nitrogen concentration was positively correlated with CO2 and N2O and negatively correlated with CH4. My third research chapter examined a long-term (15-year) record of GHG emissions from soils in rural forests, urban forest, and urban lawns in Baltimore, MD. CO2, CH4, and N2O emissions showed positive correlations with temperature at each site. Lawns were a net source of CH4 + N2O, whereas forests were net sinks. Gross CO2 fluxes were also highest in lawns, in part due to elevated growing-season temperatures. While land cover influences GHG emissions from soils, the overall role of land cover on this flux is very small (< 0.5%) compared with gases released from anthropogenic sources, according to a recent GHG budget of the Baltimore metropolitan area, where this study took place.
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Lake Albert/Mobutu lies along the Zaire-Uganda border in 43/57 per cent ratio in the faulted depression tending south-west to the north east. It is bounded by latitudes 1o0 n to 2o 20’ N and longitudes 30o 20’ to 31o 20’E. It has a width varying from 35 to 45 km (22 to 28 miles) as measured between the scarps at the lake level. It covers an area of 5600km2 and has a maximum depth of 48m. The major inflow is through the Semiliki, an outflow of Lake Edward, Muzizi and Victoria Nile draining lakes Victoria and Kyoga while the Albert Nile is the outflow. The physical, chemical and biological productivity parameters are summarized in Table 1. The scarp is steep but not sheer and there are at least 4 tracks leading down it to villages on the shore and scarp land scarp is a young one, formed as a result of earth movements of the Pleistocene times, and the numerous streams come down headlong down its thousand feet drop, more often than not in falls (Baker, 1954). Sometimes there appears to be a clean fault; and at other places there is the appearrence of step faulting, although this may be of only a superical nature .The escarpment’s composed of rocks belonging to the pre-Cambrian Basement complex of the content; but the floor of the depression is covered with young sedimentary rocks, known as kaiso beds. In their upper part these latter beds contains many pebbles; whilst low down the occurrence fossiliferous beds is sufficiently rare phenomenon in the interior plateau of Africa. The kaiso beds dated as possibly middle Pleistocene in age, are exposed in various flats on the shore, and they presumably extend under the relatively shallow waters of the lake. A feature of the shore is the development of sandpits and the enclosure of lagoons; and these can be observed in various stages of development at kaiso, Tonya, kibiro, Buhuka and above all, at Butiaba. On an island lake over 1100 km (700 miles) from the shores of the Indian Ocean one can thus study some of the shore-line phenomena usually associated with the sea- coast (Worthington, 1929). In the north, from Butiaba onwards, the flats become wider and from a continuous lowland as the lake shore curves away from the straight edge of the escarpment. At a height of just 610m (2000 feet) above sea-level, the rift valley floor at Butiaba has a mean annual temperature of 25.60c (780 f), from which there is virtually no seasonal variation; and and the mean daily range is only 6.50c (130f) (E.Afr. met. Dept.1953). With a mean annual rainfall of not much more than 762mm (309 inches) and only 92 rain days in ayear, again to judge from Butiaba, conditions in the rift valley are semi-arid; and the vegetation cover consists of grasses and scattered drought-resisting trees and bushes. Only near the stream courses does the vegetation thicken.
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Land-use change can have a major influence on soil organic carbon (SOC) and above-ground C pools. We assessed a change from native vegetation to introduced Pinus species plantations on C pools using eight paired sites. At each site we determined the impacts on 0–50 cm below-ground (SOC, charcoal C, organic matter C, particulate organic C, humic organic C, resistant organic C) and above-ground (litter, coarse woody debris, standing trees and woody understorey plants) C pools. In an analysis across the different study sites there was no significant difference (P > 0.05) in SOC or above-ground tree C stocks between paired native vegetation and pine plantations, although significant differences did exist at specific sites. SOC (calculated based on an equivalent soil mass basis) was higher in the pine plantations at two sites, higher in the native vegetation at two sites and did not differ for the other four sites. The site to site variation in SOC across the landscape was far greater than the variation observed with a change from native vegetation to introduced Pinus plantation. Differences between sites were not explained by soil type, although tree basal area was positively correlated with 0–50 cm SOC. In fact, in the native vegetation there was a significant linear relationship between above-ground biomass and SOC that explained 88.8% of the variation in the data. Fine litter C (0–25 mm diameter) tended to be higher in the pine forest than in the adjacent native vegetation and was significantly higher in the pine forest at five of the eight paired sites. Total litter C (0–100 mm diameter) increased significantly with plantation age (R2 = 0.64). Carbon stored in understorey woody plants (2.5–10 cm DBH) was higher in the native vegetation than in the adjacent pine forest. Total site C varied greatly across the study area from 58.8 Mg ha−1 at a native heathland site to 497.8 Mg ha−1 at a native eucalypt forest site. Our findings suggest that the effects of change from native vegetation to introduced Pinus sp. forest are highly site-specific and may be positive, negative, or have no influence on various C pools, depending on local site characteristics (e.g. plantation age and type of native vegetation).
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Starting from the relationship between urban planning and mobility management, TeMA has gradually expanded the view of the covered topics, always remaining in the groove of rigorous scientific in-depth analysis. During the last two years a particular attention has been paid on the Smart Cities theme and on the different meanings that come with it. The last section of the journal is formed by the Review Pages. They have different aims: to inform on the problems, trends and evolutionary processes; to investigate on the paths by highlighting the advanced relationships among apparently distant disciplinary fields; to explore the interaction’s areas, experiences and potential applications; to underline interactions, disciplinary developments but also, if present, defeats and setbacks. Inside the journal the Review Pages have the task of stimulating as much as possible the circulation of ideas and the discovery of new points of view. For this reason the section is founded on a series of basic’s references, required for the identification of new and more advanced interactions. These references are the research, the planning acts, the actions and the applications, analysed and investigated both for their ability to give a systematic response to questions concerning the urban and territorial planning, and for their attention to aspects such as the environmental sustainability and the innovation in the practices. For this purpose the Review Pages are formed by five sections (Web Resources; Books; Laws; Urban Practices; News and Events), each of which examines a specific aspect of the broader information storage of interest for TeMA.
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Agricultural activity has direct consequences on the soil and water quality. Thus, assessing environmental impacts of this vital economic activity, through soil attribute analysis, is essential to the proposal of alternatives. The aim of this study was to analyze soil quality under different land management practices, conventional and organic. The study was carried out in a watershed of the Ibiuna municipality, SP, Brazil, an important supplier of agricultural products for the São Paulo metropolitan area. A hundred samples were collected, 20 in each type of land use: reforested areas, native vegetation, pasture, conventional cultivation and organic cultivation. The soil resistance to penetration, its pH (in water and KO), electrical conductivity, bulk density, particle density, porosity, soil color, soil texture and the percentages of carbon and nitrogen were analyzed. The data were statistically analyzed, searching for significant differences. The results of soil analysis showed great similarity between the organic and conventional culture, with no statistical differences. However, organic cultivation showed greater similarity to the soil of native vegetation in the percentage of carbon and nitrogen in soils compared to conventional culture. Thus, the discussion begins on a topic very little explored so far, and the results obtained should be further studied.
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Urban forests are often highly fragmented with many exotic species. Altered disturbance regimes and environmental pollutants influence urban forest vegetation. One of the best ways to understand the impacts of land-use on forest composition is through long-term research. In 1998, the Baltimore Ecosystem Study established eight forest plots to investigate the impacts of urbanization on natural ecosystems. Four plots were located in urban forest patches and four were located in rural forests. In 2015, I revisited these plots to measure abundances and quantify change in forest composition, diversity, and structure. Sapling, shrub, and seedling abundance were reduced in the rural plots. Alpha diversity and turnover was lower in the rural plots. Beta diversity was reduced in the rural plots. The structure of the urban plots was mostly unchanged, except for a highly reduced sapling layer. Beta diversity in the urban plots was consistent across surveys due to high species turnover.
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Electric vehicle (EV) batteries tend to have accelerated degradation due to high peak power and harsh charging/discharging cycles during acceleration and deceleration periods, particularly in urban driving conditions. An oversized energy storage system (ESS) can meet the high power demands; however, it suffers from increased size, volume and cost. In order to reduce the overall ESS size and extend battery cycle life, a battery-ultracapacitor (UC) hybrid energy storage system (HESS) has been considered as an alternative solution. In this work, we investigate the optimized configuration, design, and energy management of a battery-UC HESS. One of the major challenges in a HESS is to design an energy management controller for real-time implementation that can yield good power split performance. We present the methodologies and solutions to this problem in a battery-UC HESS with a DC-DC converter interfacing with the UC and the battery. In particular, a multi-objective optimization problem is formulated to optimize the power split in order to prolong the battery lifetime and to reduce the HESS power losses. This optimization problem is numerically solved for standard drive cycle datasets using Dynamic Programming (DP). Trained using the DP optimal results, an effective real-time implementation of the optimal power split is realized based on Neural Network (NN). This proposed online energy management controller is applied to a midsize EV model with a 360V/34kWh battery pack and a 270V/203Wh UC pack. The proposed online energy management controller effectively splits the load demand with high power efficiency and also effectively reduces the battery peak current. More importantly, a 38V-385Wh battery and a 16V-2.06Wh UC HESS hardware prototype and a real-time experiment platform has been developed. The real-time experiment results have successfully validated the real-time implementation feasibility and effectiveness of the real-time controller design for the battery-UC HESS. A battery State-of-Health (SoH) estimation model is developed as a performance metric to evaluate the battery cycle life extension effect. It is estimated that the proposed online energy management controller can extend the battery cycle life by over 60%.
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The health of people living with HIV and AIDS (PLWHA) is nutritionally challenged in many nations of the world. The scourge has reduced socio-economic progress globally and more so in sub-Saharan Africa (SSA) where its impact has been compounded by poverty and food insecurity. Good nutrition with proper drug use improves the quality of life for those infected but it is not known how PLWHA exposed to chronic malnutrition and food shortages from developing nations adjust their nutrition with use of Anti-Retro-viral Drugs (ARVs). This study assessed nutritional status, dietary practices, and dietary management of common illnesses that hinder daily food intake by the patients and use of ARVs with food recommendations provided by the health care givers. A descriptive case study design was used to sample 120 HIV-infected patients using systematic sampling procedure. These patients sought health care from an urban slum, Kibera AMREF clinic. Data were collected by anthropometric measurements, bio-chemical analysis, semi-structured questionnaire and secondary data. The Statistical Package for Social Sciences (SPSS) and the Nutri-Survey software packages were used to analyze data. Dietary intakes of micro-nutrients were inadequate for >70% of the patients when compared to the Recommended Daily Requirements. When Body Mass Indices (BMI) were used, only 6.7% of the respondents were underweight (BMI<18.5kg/m2) and 9.2% were overweight (BMI> 25kg/m2), serum albumin test results (mean 3.34±0.06g/dl) showed 60.8% of the respondents were protein deficient and this was confirmed by low dietary protein intakes. The BMI was not related to dietary nutrient intakes, serum albumin and CD4 cell counts (p>0.05). It appeared that there was no significant difference in BMI readings at different categories of CD4 cell count (p>0.05) suggesting that the level of immunity did not affect weight gain with ARV as observed in many studies from developed countries. Malnutrition was, therefore, evident among the 60.8% of the cases as identified by serum albumin tests and food intake was not adequate (68%) for the patients as they ate once a day due to lack of food. National food and nutrition policy should incorporate food security boosting guidelines for the poor people infected with HIV and using ARVs.
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Reports of triatomine infestation in urban areas have increased. We analysed the spatial distribution of infestation by triatomines in the urban area of Diamantina, in the state of Minas Gerais, Brazil. Triatomines were obtained by community-based entomological surveillance. Spatial patterns of infestation were analysed by Ripley’s K function and Kernel density estimator. Normalised difference vegetation index (NDVI) and land cover derived from satellite imagery were compared between infested and uninfested areas. A total of 140 adults of four species were captured (100 Triatoma vitticeps, 25 Panstrongylus geniculatus, 8 Panstrongylus megistus, and 7 Triatoma arthurneivai specimens). In total, 87.9% were captured within domiciles. Infection by trypanosomes was observed in 19.6% of 107 examined insects. The spatial distributions of T. vitticeps, P. geniculatus, T. arthurneivai, and trypanosome-positive triatomines were clustered, occurring mainly in peripheral areas. NDVI values were statistically higher in areas infested by T. vitticeps and P. geniculatus. Buildings infested by these species were located closer to open fields, whereas infestations of P. megistus and T. arthurneivai were closer to bare soil. Human occupation and modification of natural areas may be involved in triatomine invasion, exposing the population to these vectors.
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Transportation system resilience has been the subject of several recent studies. To assess the resilience of a transportation network, however, it is essential to model its interactions with and reliance on other lifelines. In this work, a bi-level, mixed-integer, stochastic program is presented for quantifying the resilience of a coupled traffic-power network under a host of potential natural or anthropogenic hazard-impact scenarios. A two-layer network representation is employed that includes details of both systems. Interdependencies between the urban traffic and electric power distribution systems are captured through linking variables and logical constraints. The modeling approach was applied on a case study developed on a portion of the signalized traffic-power distribution system in southern Minneapolis. The results of the case study show the importance of explicitly considering interdependencies between critical infrastructures in transportation resilience estimation. The results also provide insights on lifeline performance from an alternative power perspective.
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Soil tillage with chisel ploughing is the conventional soil management system in chestnut stands for fruit production in Northern Portugal. A study was developed to assess the effects of three soil management systems on in situ soil N mineralization dynamics, tree nutrition status and fruit productivity, in a 50-yr old chestnut stand. The treatments were: conventional tillage with a chisel ploughing twice a year (CT), no-tillage with rainfed improved pasture with leguminous and grasses plants (NIP), and no-tillage with spontaneous herbaceous vegetation - natural pasture (NP). The CT treatment showed a strong increase of the soil N mineral concentration following soil disturbance by tillage, but the cumulative net N mineralized along the year was significantly lower (51.8 kg ha-1) than in the NIP (85.1 kg ha-1) treatment. The NP treatment (65.9 kg ha-1) did not cause a reduction in the soil N mineralization when compared to the CT treatment. The mineralization rate (g mineralized N kg-1 total N) in 2004 was about 26, 30 and 38 in the treatments CT, NP and NIP, respectively. Treatments showed different soil N dynamics, the proportion of mineralized NO3--N being lower in the NP (10-48%) than in CT and NIP treatments (53-74%). Our study indicates that no-tillage systems improve the tree nutrition status and enhance productivity
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Doutoramento em Engenharia Florestal - Instituto Superior de Agronomia - UL