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Introduktion: Dental erosion definieras som förlust av tandens hårdvävnad genom en kemisk process som inte involverar bakterier. Dagens förändrade livsstil och kosthållning medför att våra tänder oftare utsätts för kemisk påverkan som kan leda till erosion. Det är flera faktorer som samverkar och dental erosion har en multifaktoriell etiologi. Syfte: Syftet är att beskriva olika registreringsmetoder för dental erosion. Frågeställningar: Vilka metoder kan användas för registrering av initial erosion? Vilka metoder kan användas för registrering av avancerad erosionsskada? Vilka metoder är kliniskt beprövade på patient? Metod: Litteraturstudie Resultat: Ett flertal registreringsmetoder fanns beskrivna i litteraturen, merparten var inte applicerbara kliniskt. Registeringsmetoderna som framgick i den beskrivande litteraturstudien var: 3D scanning microscope (IFM), Atomic absorption spectroscopy (AAS), Digital photography (DP), Focus-variation 3D microscopy (FVM), Longitudinal microradiography (LMR), Non-contact confocal laser scanning microscopy (CLSM), Optical assessment, Optical profilometry (OP), Quantitative light-induced fluorescence (QLF), Scanning electron microscopy (SEM), Stylus profilometry (SP), Ultrasound, White light interferometry (WLI) och X-ray diffraction (XRD). Konklusion: Vid registrering av initial erosion krävs analys av tandytans mineralinnehåll samt optiska analyser med hjälp av instrument. För analysering av progredierande erosion används yt-råhetsanalyser. Röntgenbildtagning och mikroradiografi används för en analys av avancerad erosion. För kliniskt bruk finns QLF metoden, digital bildtagning och optisk analys.

A research program was undertaken to quantify the effect of flow induced erosion on the stability of natural river banks along the Red River in Winnipeg, Manitoba. The study correlated the percent decrease in factor of safety to intensity of river flow and duration. Two methods to quantify flow induced erosion were assessed, the first method based on observed erosion and the second on theoretically calculated erosion. The first method involved aligning annual historical river bank cross-sections and measuring the distance between cross-sections to represent the erosion induced from the flow year between successive cross-sections. Due to the fact there are no sites along the Red River regularly surveyed, the analysis did not provide for a correlation between erosion from a specific flow event to percent decrease in factor of safety. The second part involved the use of theoretical equations to quantify erosion given the river elevation of a specific flow year. The study showed a 1% to 8% decrease in factor of safety from low to high intensity flows and as high as 14.5% for high intensity flows of long duration. Additionally, the evolutionary stability of the riverbank was generated showing the percent decrease each year in factor of safety due to erosion and the years during which failure occurs. The results correlated well to the previous analysis showing a 1% to 5% decrease for low to high intensity flows respectively and as high as 10% for high intensities of long duration.

Willow bioengineering is an alternative erosion management technique that includes the use of living and inert willow material. It is successfully used across North America, Europe and Asia but, due to lack of public awareness of the technique or concerns about its effectiveness, it is currently used only occasionally in southern Manitoba. To provide insight into possible biological limitations upon the use of willows to prevent erosion a combination of field experiments and observational studies of new bioengineering sites was carried out across southern Manitoba. The results indicate that first year willow cutting survival is likely to be below 50% unless planted within 100cm of fall low water level. Using taller cuttings may improve survival as they develop greater numbers of shoots early in the growing season, but taller cuttings have a greater chance of being cut down or even pulled from the ground by beaver. Flooding had a negative effect of shoot numbers during the first year after planting, although it did not impact survival. In 2012 flood levels were lower at the majority of sites than the long term mean; more extensive flooding may have a more negative effect upon the cuttings. Maximum shoot length was reduced by high water levels, but was improved by cutting proximity to low water later in the summer. More research is needed to better understand the effect of high water levels on long term survival. Combining live willow with erosion blanket helps reduced substrate loss during establishment and also prevented willow bundles from being removed by beaver reducing the potential of project failure.

Complex relationships exist among offshore conditions, beach sediment transport and morphology, and till cliff erosion. Modelled and measured sediment transport rates established for the Holderness coast are similar to those on comparable coasts elsewhere. The direction of sediment drift depends on wave approach, and determining sediment transport rates, cliff composition and cliff retreat rates allows a sediment budget to be prepared. The beach response predicted by the sediment budget was confirmed by field observations, with budget surpluses and deficits coinciding with full and depleted beach profiles respectively. The area of deficit in the north of the study area was associated with the reduced sheltering effect of Flamborough Head on sediment drift. At most profiles, especially those with a sediment deficit, high energy waves may remove the sand veneer completely, leaving the till platform exposed. These bare till patches which elsewhere have been called ords and have been regarded as unique, were thought, in the present study,to represent a normal beach response to limited sediment supply and prevailing offshore conditions. Beach evolution was also modelled formally, the range of beach profiles exhibited on the Holderness coast being grouped into a number of distinct types, and evolution among them described and predicted by a first-order Markov model. This can be refined to provide different models for "winter" and "summer". Different modal types occur at different locations, and certain types of transitions between classes can be associated with particular ranges of wave conditions. Beach Development, Sediment Budget and Coastal Erosion at Holderness Susan J. Mason. Till cliff retreat at Holderness is extremely variable, both spatially and temporally, being influenced by beach level, energy conditions, cliff moisture content and the actions of man. The sediment transport rates, cliff retreat data, sediment budget and beach behaviour model are all essential elements of a research programme currently being undertaken to find a cheap method of protecting this coast.

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No description available.

No description available.

This is a study of the relationship between livelihood strategies, soil fertility investment and land use in the village of Fandou Ben, southwestern Niger. The aim has been to place alleged soil degradation in a specific, differentiated and dynamic local context. The village, which is populated by Djerma and Fulani, has a low population density. The agricultural system is dominated by millet cultivation on poor soils. It now depends on short-fallow periods to restore fertility, other sources of inputs being limited. There are high erosion rates and an annual precipitation of 600mm with high variability. The local narrative can be interpreted to represent this landscape as a lifescape: an environment that is a product of a complex sequence of agricultural decisions and livelihood responses. The flexibility in the ways in which the farmers manage their soil is a reflection of the ephemerality of the factors that govern soil productivity and the need to adapt to natural biodiversity and spatial variability. They relied on their local knowledge to maximise productivity, as in their precision application of organic inputs, the ways in which they are increasingly integrating smallstock into their strategies, and the increasing signs of ethnic cooperation. Using a Sustainable Rural Livelihoods framework, the key determinants of land allocation and soil investment were found to be household productive capacity, the productive potential of the land, the degree of household livelihood diversification, and the farmer's capacity to recognise opportunities, prioritise and enact entitlement. The household's endowments were dynamic and spatially differentiated. The diversity of livelihood situation, knowledge, experience, and perceptions of power and identity created many different routes of livelihood response, and varying rates of agricultural investment. Within these multiple pathways, there were dynamic transformations between natural capital and the non-farm component of rural dwellers' livelihoods.