410 research outputs found
Estmating groundwater changes in the Rufiji basin by using data from the GRACE satellites
No full textHG 13 2014 Preface This Bachelor's thesis is Carl Lindgren's degree project in Hydrology and Hydrogeology at the Department of Physical Geography and Quaternary Geology, Stockholm University. The Bachelor's thesis comprises 15 credits (one half term of full-time studies). Supervisor has been Steve Lyon at the Department of Physical Geography and Quaternary Geology, Stockholm University. Examiner has been Ian Brown at the Department of Physical Geography and Quaternary Geology, Stockholm University. The author is responsible for the contents of this thesis. Stockholm, 11 July 2014 Lars-Ove Westerberg Director of studies Estimating groundwater changes in the Rufiji basin by using data from the GRACE satellites 1 Abstract Groundwater is an important water resource and vital for providing water to sustain human life and livelihoods around the world. It is a renewable resource but recharge is often a slow process and there is therefore a significant risk for overuse. It is therefor of importance to monitor how groundwater develops over time, which is a difficult process as changes in groundwater are difficult and expensive to measure. This becomes an even larger issue in developing countries or areas where measurements in the field cannot be performed due to political or economic reasons. The launch of the GRACE satellites in 2002 made it possible to follow groundwater developments through remote sensing and this possibility has been used in numerous studies around the world. This study used the methods developed in previous studies to measure groundwater developments in the Rufiji basin in Tanzania. For the study period 2003 to 2012 no clear trends could be identified in groundwater and the larger variations that occurred during the period coincided with years of more or less precipitation than average precipitation. There is a strong seasonality in groundwater with the lowest levels prior to the rainy season and the highest levels at the end of the rainy season that clearly could be identified from the GRACE data. Although data from the GRACE satellites are a very powerful tool to monitor groundwater developments the low spatial resolution limits its practical applications. For the Rufiji basin, which has large variation in topography and human concentration, groundwater developments are likely to be unevenly distributed which cannot be measured using GRACE due to this spatial limitation
Mot ett nytt tandvårdssystem
No full textI denna artikel presenteras och belyses olika förutsättningar och förslag att förändra nuvarande försäkringssystem inom tandvården. Strävan att förändra tandvårdsförsäkringen hänger samman med den förbättrade tandhälsan och innehållet i den nya tandvårdslagen.
Lars G Petersson är docent och klinikchef vid Odontologiska specialistkliniken i Halmstad och Ingvar Westerberg fil. dr. och högskolelektor, Ekonomiska institutionen, universitetet i Linköping
In the eye of the beholder : bias and stochastic variation in cover estimates
No full textCover estimates by eye is a prevailing method to assess abundance. We examined cover estimates with regard to bias and random variation. Ten observers working with a national forest vegetation survey estimated sixteen 100 m(2)-plots, placed in two different vegetation types. These had similar species composition but were clearly distinguishable in the field. In species-wise analyses, observer bias varied greatly, with Dicranum spp., Vaccinium vitis-idaea and Vaccinium myrtillus having the largest bias. Experience had a surprisingly small impact on variation. Power analysis revealed only small differences between observers in the ability to distinguish the two vegetation types, and little value in averaging the assessments from two, three or four observers. Cover estimates did better than presence/absence data in separating the two vegetation types and multivariate analyses were more powerful than univariate ones.The original publication is available at www.springerlink.com:Johan Bergstedt, Lars Westerberg and Per Milberg, In the eye of the beholder: bias and stochastic variation in cover estimates, 2009, PLANT ECOLOGY, (204), 2, 271-283.http://dx.doi.org/10.1007/s11258-009-9590-7Copyright: Springer Science Business Mediahttp://www.springerlink.com
Geomorphology and pedology of the Engaruka archaeological environment, Tanzania, and the effects of the 1997–1998 El Niño flash-flood
No full textExperiences of Banner advertisement on a specialized homepage
No full textTitle: Experiences of Banner advertisement on a specialized homepage Author: Marcus Westerberg Supervisor: Marie Hemming Department: Department of Business Administration, IEM Course: Bachelor thesis in Business Administration, FEC 007 Purpose: Create a understanding for how the users on Internet pages experience the occurrence and the shape of the banners. Method: Methods used are quantitative and qualitative, and the facts and figures are based on a pop up inquiry and some telephoneinterviews. I elected pop up inquiry and telephoneinterview as my data collection. My inquiry had a high grade of standardization and the interviews had a low grade of standardization. Result: On the basis of the question of issue I have drawn the conclusion that the users feels that it is important with information in all advertising. It is also important for the users to create a value around the product. The users do not have the time to figure out the message behind advertising, the want simple and massive information about the product/service. It´s important for the users that the banneradvertising are about things that they are interested in. Only then the users will be drawn to the banneradvertising on different homepages.Titel: Upplevelser av bannerreklam på en nischad hemsida Författare: Marcus Westerberg Handledare: Marie Hemming Institution: Institutionen för ekonomi och management, IEM Kurs: Kandidatarbete i företagsekonomi, FEC 007 Syfte: Skapa en förståelse för hur användare på Internet upplever förekomsten och utformningen av bannerreklamen. Metod: Uppsatsen är baserad på en kvantitativ såväl som kvalitativ ansats där fakta har inhämtats med en pop up enkät och telefonintervjuer. För insamlingen av pop up enkäten använde jag mig av strukturerade frågor, där frågor och svarsalternativ redan hade bestämts på förhand. För insamlingen av telefonintervjuer använde jag mig av frågor med låg grad av standardisering. Slutsatser: Utifrån frågeställningen har jag kommit fram till att användarna upplever att det är viktigt med fakta och information i bannerreklamen. Det är viktigt för användarna att skapa ett värde kring produkten. Användarna har inte tid att tänka ut budskapet bakom reklamen, utan de vill ha enkel och mycket information om varan/tjänsten i reklamen. Det är viktigt för användarna att reklamen ska handla om det de är intresserade av. Det är då de dras till bannerreklamen på olika hemsidor
Model Predictive Control of a Combined EGR/SCR HD Diesel Engine
No full textMaterials Noise, Vibration and Harshness Parts and Components Power and Propulsion Quality, Reliability and Durability Safety Tests and Testing Transportation Systems Vehicles and Performance Other Options Papers by Event SAE Home > Papers> By Event> SAE 2010 World Congress & Exhibition Model Predictive Control of a Combined EGR/SCR HD Diesel Engine Date Published: 2010-04-12Paper Number: 2010-01-1175 DOI: 10.4271/2010-01-1175 Author(s): Claes Westerlund - Scania CV AB Bjorn Westerberg - Scania CV AB Ingemar Odenbrand - Lund Univ. Rolf Egnell - Lund Univ. View All CollapseAbstract Achieving upcoming HD emissions legislation, Euro VI / EPA 10, is a challenge for all engine manufacturers. A likely solution to meet the NO x limit is to use a combination of EGR and SCR. Combining these two technologies poses new challenges and possibilities when it comes to optimization and calibration
L-Band Polarimetric Target Decomposition of Mangroves of the Rufiji Delta, Tanzania
No full textThe mangroves of the Rufiji Delta are an important habitat and resource. The mangrove forest reserve is home to an indigenous population and has been under pressure from an influx of migrants from the landward side of the delta. Timely and effective forest management is needed to preserve the delta and mangrove forest. Here, we investigate the potential of polarimetric target decomposition for mangrove forest monitoring and analysis. Using three ALOS PALSAR images, we show that L-band polarimetry is capable of mapping mangrove dynamics and is sensitive to stand structure and the hydro-geomorphology of stands. Entropy-alpha-anisotropy and incoherent target decompositions provided valuable measures of scattering behavior related to forest structure. Little difference was found between Yamaguchi and Arii decompositions, despite the conceptual differences between these models. Using these models, we were able to differentiate the scattering behavior of the four main species found in the delta, though classification was impractical due to the lack of pure stands. Scattering differences related to season were attributed primarily to differences in ground moisture or inundation. This is the first time mangrove species have been identified by their scattering behavior in L-band polarimetric data. These results suggest higher resolution L-band quad-polarized imagery, such as from PALSAR-2, may be a powerful tool for mangrove species mapping
Biofuel potential and land availability : The case of Rufiji District, Tanzania
No full textAfrica’s attractiveness to potential biofuel investors is based on the assumption that there is plenty of unused land available for investment in different countries of the continent. However, their postulations are not based on any concrete studies about land availability at country, regional or local level. This study investigates land availability for potential biofuel investment at the local level, using Rufiji district in Tanzania as a case study. We have analyzed different land cover/land use types and separated them into areas of potential biofuel investment and areas where biofuel investment is not possible by a process of elimination. The results suggest that land availability is inadequate to meet the needs of biofuel investors. The land assumed to be unused or underutilized by biofuel investors is either part of the fallow system or used to harvest natural resources and for other traditional uses. Expropriating the assumed idle land will adversely impact on the livelihoods of the local communities
Geomorphology and environmental dynamics in Save River delta, Mozambique [Elektronisk resurs] : A cross-timescale perspective
No full textLong-term perspectives on the evolution of river deltas have provided useful knowledge capable of responding to pending questions related to the ongoing climate and environmental changes. Increasing utilization pressure on delta environments has necessitated increased attention to protect the socio-economic and ecological values. As a result, multiple local initiatives have been designed, aimed at mitigating environmental deterioration and implementing adaptive measures, but many such initiatives have shown limited success. This thesis uses a case study of Save River delta in Mozambique to explore the relation between geomorphological evolution and socio-ecological system dynamics in delta environments. In addition, key environmental variables that concern the society today are highlighted and discussed in a management perspective. The results of the study show the development of Save River delta from the mid-Holocene to the present. The geomorphological settings of the delta suggest a faulted coastline over which subsequent deposition of fluvial sediments has formed a protruding delta front. Between c. 3000 and 1300 years ago, fine-grained sediments accumulated on top of the delta-front in the proximal part of the delta. This type of material was deposited under intertidal conditions and supported the formation of mangrove habitat. The geographical distribution of the mangrove deposit was driven by successive stages of back-barrier swamp formation and sea-level change as the delta evolved. From c. 1300 years ago, the river delta started to receive fluvial sediments from pulses of floods forming an alluvial floodplain. These sediments have accumulated mainly on the fine-grained mangrove wetland deposit. All the geomorphological features have evolved in a shoreward-shifting pattern over time. Centennial to decadal changes observed in the delta have followed a predictable geomorphological pattern, which is also part of the millennial evolution. The mangrove system, the base for the socio-economic system, is consequently strongly affected by the geomorphological development of the area. An increasing sensitivity of socio-ecological systems to environmental stressors, e.g. floods, cyclones and erosion, has motivated multiple initiatives to work towards a sustainable management of delta environments. This thesis highlights the need for interplay between geomorphology and ecology, considering both long- and short-term dynamics of delta environments. Hitherto, management initiatives have been concentrated on fragmented interventions of controlling water flow, which have disrupted the natural dynamics by obstructing the sedimentation-erosion cycle. To change this trend, coastal planners need to consider the significance of natural processes, e.g. cyclones, floods, erosion and accretion, for the long-term ecological and social sustainability of delta environments.</p
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