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387 Uppsatser om Northern Ireland - Sida 17 av 26
Spawning site selection of brown trout in habitat restored streams
During the timber floating era, most of Sweden?s watercourses were altered. This decreased the amount of available spawning habitats for salmonids, and hence had a negative effect on the riverine brown trout (Salmo trutta) populations. Reconstruction of spawning grounds is today a common measure in restoration of altered streams in Sweden. However, very little evaluation of the effectiveness of these reconstructed spawning grounds exists.
Trafikverkets effektstyrningssystem - EFS 132 kV : Bidraget till minskade förluster
The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.
Kan markfuktighetskartor användas för att hitta skogsmark med hög bonitet? : ett gis-baserat försök med dtw-index och laserskannad övre höjd
The depth-to-water-index (DTW-index) is derived from digital elevation models (DEM) to map soil wetness, in terms of distance from soil surface to the ground water table. The aim of this GIS based study was to investigate the existence of a relationship between DTW-index and forest site productivity (SP). The belief of such an assumed relationship was based on knowledge that the ground water level is related to site properties that can either promote or impede tree growth.
Data primarily comprised rasters of the Krycklan catchment in northern Sweden and depicted DTW-index and a laser scanned vegetation height. The 100th height percentile of each pixel in the vegetation raster was assumed to mirror the top-height, letting it act as a relative measure of SP within a delineated area of equal stand age.
Beror KRAV-grisars ledanmärkningar på miljöfaktorer?
This project investigated how elevation and vegetation type influences variation in plant litter phenolic content and protein precipitation capacity among and within common plant species for two different vegetation types, heath and meadow, in a subarctic ecosystem in the Abisko region of northern Sweden. As nutrient availability generally decreases with increasing elevation as a result of decreasing temperature, I hypothesised that phenolic content would increase with elevation and be higher on the heath than the meadow. To test this, the total phenolic content and protein precipitation capacity was estimated in leaf litter from 13 species in both heath and meadow vegetation across an elevational gradient ranging from 500 to 1000 meters above sea level (m.a.s.l.) in the study region. The results showed that elevation and vegetation type both had a strong impact on both variables. Total phenolic concentrations decreased with elevation for the meadow, and were greater for the heath than the meadow.
African swine fever in Uganda : attitudes and possible interventions to limit the spread of the disease
The objective of this study was to investigate the attitude towards African swine fever (ASF) primarily among smallholder pig farmers but also among other actors along the pork value chain in Gulu district, Uganda. More specifically, the study aimed to investigate the specific
challenges facing both farmers and other members of the pork value chain using participatory epidemiology (PE).
ASF is a feared viral disease of pigs associated with high mortality, which is endemic in many parts of Africa. The recent history of Gulu district in Northern Uganda can be described as turbulent and the human population has suffered during decades of war and civil unrest. Pig
keeping is considered a potential opportunity for business as well as a way of providing more animal protein in the diet. However, this is threatened by ASF as farmers can lose entire herds due to the disease.
This study can confirm some previously known factors and risk activities such as the free range system of pigs and movement of pigs and pork during ongoing outbreaks, which make disease control difficult.
Införande av mjuka golv för mjölkkor : en fallstudie
Soft rubber flooring have gained in popularity over the last years. Rubber flooring al-lows cow to move more freely without slipping and improves claw and leg health. The purpose of this study was to investigate the influence of a stepwise introduktion of soft flooring on cow`s placement in cow houses with robotic milking.
A case study was carried out in a herd in northern Sweden with 41 cows. Observations were made every 15 minutes between 09.00 and 16.00 concering cow placement in cu-bicles, in cubicle alley, in feeding alley and in feeding alley with the head through feed-ing gate. One observation period was carried out per flooring alternativ: 1) all concrete slatted floor, 2) rubber slatted floor in feeding alley and concrete slatted floor in cubicle alley and 3) rubber slatted floors in feeding alley and solid rubber floors in cubicle alley.
The study showed that 6 %-units fewer cows lay in the cubicles when the feeding alley surface was slatted rubber.
Motiv och avkastningsvärde vid köp av skogsfastigheter : en intervjuundersökning
The purpose of this paper has been to find out what motives buyers of forest property has for there purchasse, what competence they have in economics and forestry, and what analysis they had done before the purchase. The study is based on interviews with nine different buyers from two geographical areas, five from Hälsingland and four from Småland/Skåne. A forest property is a property where the value to 100 % consist of forest. A part from the interviews every purhase has been analysed in comparison to an estimation of the yield value. The theoretical yield value was estimated with a computer programme.
Svartgran ? ett alternativ när allt ser mörkt ut? : en kartmodell för att visa lämpliga ståndorter för odling av svartgran
A common problem in forestry is plant death caused by frost. The risk of frost is highest on wind protected, flat or low-lying areas in the terrain. Here you often have regeneration problems with Norwegian spruce which is especially sensitive to spring frost. Swedish tree experiments have shown that the black spruce can be a suitable alternative on these areas, for example on moisture frost prone areas. The species originates from North America and its pioneer tree characteristics make it more frost hardy than Norwegian spruce.
Relationship between moose (Alces alces) home range size and crossing wildlife fences
Wildlife fences are today commonly used along highways to reduce the risk of vehicle collisions with wildlife. Since traffic and roads have expanded over the years, wildlife behaviour has become more interesting not only for the prevention of vehicle collisions but also to understand how human activities impact their natural habitats. Moose is one of those animals that have increased in interest in such studies. In this study, I tested if the probability to cross wildlife fences of moose would increase with increasing home range sizes, and also at what time of the year they cross. The study area is situated in Nordmaling municipality, located in Northern Sweden in the County of Västerbotten.
Kväveomsättning i gräsmark med olika artantal och artsammansättningar :
This study was carried out at the Swedish University of Agricultural Sciences, Dept. of
Agricultural Research for Northern Sweden. The aim of the study was to determine how plant species richness and diversity influence the nitrogen pools and nitrogen fluxes in the soil. Plant and soil samples from a biodiversity experiment in grasslands were used. Thirty plots with 12 grassland plant species (legumes, grasses, and non-legume herbs), combined from 1-12 species were investigated.
Ruminants´production within agroforestry systems in rural Rwanda : production benefits and problems
Intercropping involving trees is called agroforestry and makes it possible to get higher production for every area unit. The trees can function as food, fodder, fuel, medicine; prevent mark erosion and much more. Agroforestry can also be combined with animal husbandry.
The aim of this study was to document the animal production systems used by rural small-scale farmers maintaining ruminants and using agroforestry in the northern province of Rwanda. The farmers using agroforestry is expected to have higher milk yield than average due to homegrown protein.
The method used during the study was semi-structural interviews with booth open and closed questions. In order to get in contact with farmers that matched the criteria; small-scaled rural farmers with ruminants and using agroforestry, the ?Vi Agroforestry Programme? (Vi-Life) in Kigali were contacted and the staff worked as supervisors, translators and contact with the farmers throughout the study.
During the study nine individual farmers, two cooperatives breeding sheep and one group interview were conducted.
Utbildning och ideologi-en komparativ analys av medborgerlig och politisk bildning i en svensk respektive kubansk kontext
Hunting ground graves were distinguished as a separate category during the 1930s. There is however no clear definition of what a hunting ground grave is. They have been constructed over a large area over a long period of time (200 BC-1200 AD) and their morphology varies.This paper investigates how the archaeologists have discussed the hunting ground graves since they were distinguished as a separate category until today. It investigates what concepts that have been used to define and categorize the graves as a group. It also investigates if the choices of concepts are depending on a broader societal perspective.To find the answers to these questions two surveys have been done.
Trygghet och samverkan i en av Sveriges mest trygga städer : En kvalitativ fallstudie om staden där nästan alla känner sig trygga.
We have in this field study been researching how social comfort is affected by the work of social services and their collaboration with police, schools and health care within a small village located countryside in the northern part of Sweden. The attribute which sets this village a part from most other small countryside villages is the fact that the crime rate is amongst the lowest in Sweden as well as the social security feeling within the inhabitants are amongst the highest. We traveled 2298 kilometers back and forth to be able to interview professionals and gather empiric material for this study. The method we have used for data collection has been in the form of semi structured interviews. We have used previous research concerning collaboration, social comfort, social discomfort and fear of crime as our aid to analyze our findings with the help of theories regarding different types of communites (gemeinschaft and gesellschaft) invented by Ferdinand Tönnies (2001) and Human Service Organisation by Hasenfeld (1983).
Föreställningen om Australiens outback : En diskursanalys av australiensiska officiella webbsidor
The Internet is a constant source of information about the world and has contributed to the globalization of texts and pictures. A part in the tourists process of consumption involves looking at pictures and read about places that create an image of places that they have never been to. Websites are therefore important as a first impression and it is here that places are being represented. Places are created on the Internet and the Australian outback is an example of this. The study is interesting because it can be used to understand the relationship between people and places.
Död ved i vatten - funktionella strukturer och dess påverkan på öring (Salmo trutta, L.)
The background to this work was to see if there was a connection between large woody debris (LWD) and the presence of brown trout in our Swedish forest streams. Previous researches by Degerman et al. (2004) have shown that there is a strong correlation between the amount of dead wood and the presence of brown trout. The goal was then to find a way to restore, maintain and increase the trout habitats by constructing and adding manmade wooden structures that would mimic natural deadwood and its features in flowing water. The inspiration was partially taken from a water restoration program in the Klamath River of northern California, USA.