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918 Uppsatser om Species interactions - Sida 52 av 62
Passage efficiency and migration behavior for adult Atlantic salmon at a Half-Ice Harbor fish ladder
Due to exploitation of the world?s rivers, the upstream migration of anadromous species is frequently delayed or even prevented. To mitigate these problems and allow fish to migrate past obstacles, structures such as fish ladders have been developed. However, recent studies show that many of the present fish passage facilities are deficient. Monitoring and evaluation of passage facilities is therefore crucial to enable necessary adjustments.
Emerging zoonotic viruses : what characterizes them and what are the risk factors for their emergence?
Emerging infectious diseases poses a great future threat, not only to humans but also to domestic animals and wildlife. Even though the majority of these infections only cause minor health problems, the relatively recent emergence of HIV clearly illustrates that the next major human pandemic may surface at any time. Regardless of what the name indicates, most emerging human pathogens are not believed to be recently evolved, but to have existed previously in the natural environment. Most emerging pathogens are zoonotic, i.e. able to infect animals besides humans.
När en norsk del av Danmark tillfogades Sverige : en ingång till att förstå bohuslänska identitetsföreställningar 1662-1668
This essay discusses the Nordic region Bohuslän the decade after it became "Swedish" in 1658, during what I call the region's "transition period". The wide cause of the study is to show how the traditional understanding of this state shift (and of state shifts in general) need to be problemized and understood in the light of the state conditions of Early Modern Europe. By examine court protocols from the local-court of Orust and Tjörn (one of five local courts in contemporary Bohuslän) and the local noble's writings to the Swedish parliament, a tricky mixture of references to different territories gets observed and analyzed.To approach the difficult identity problems, I have assistance in Peter Sahlins' conclusions from his study of the French-Spanish borderland during the same period. Especially helpful are his identity schemes by which he (inspired by the Norwegian anthropologist Fredrik Barth) supposes that each identity originates from a counter-identity. This study ends up in an attempt to reconstruct the landscape of identities and counter-identities found in the sources, according to professor Sahlins' schemes.
Flerspråkiga barns språkutveckling i förskolans praktik : Hur förskolan arbetar genom förskollärares uppfattningar, val av metoder och utformningen av den fysiska miljön
AbstractThe Swedish society has always been monolingual, but has for the past decades transformed into a multicultural and multilingual society. The aim of this study is to investigate if and in that case how preschool teachers work with language development in bilingual and multicultural preschools. The concept of linguistic and cultural diversity includes several different components, not least the social interactions that are of great importance to every individual's development, learning and participation in the world. By understanding the importance of language, language development and the role of mother tongue in second language acquisition, we look into various researches done concerning the effects of the preschool teachers? opinions, methods used to language developmental primarily for children who are multilingual and how the physical environment is shaped to promote language in multicultural and multilingual preschools.The method used in this study is semi-structured interviews with preschool teacher working in multicultural or bilingual preschool settings.
Migration losses of Atlantic salmon (Salmo salar L.) smolts at a hydropower station area in River Åbyälven, Northern Sweden : passage fates at a reservoir, a power house and a bypass structure
A large number of rivers in northern Sweden have hydropower developments that cause negative effects on both up- and downstream migrations of anadromous species like Atlantic salmon. So far, most attention has focused on the hindrances of adult fish during their upstream spawning migration. However, since turbines in power stations cause losses on downstream passing fish, the focus on negative effects on smolts has increased. The aim of this study was to compare three different causes of losses of salmon smolts passing downstream through a power station area in the flow-controlled River Åbyälven in northern Sweden.A total of 61 wild salmon smolts were caught and radio-tagged in the River Åbyälven during their downstream migration in June 2009. The salmon smolts were released at three locations, 1.1 km upstream from the power station, in the turbine intake and in the upper part of a fishway, acting both for up- and downstream fish passage.
En pilotstudie av unghästars användning av ligghall i grupphållningssystem
Today, individual indoor stalls and individual outdoor paddocks are the most common way to house horses in Sweden. The way that we manage, house and feed the horses are not optimal for the species natural basic behavioural needs. However, the awareness of this grows in the context of research and the emergence of alternative housing systems. One of the alternatives to the traditional format in individual boxes is called group housing. Group housing systems allow horses to live in herds and they can choose how they want to distribute the hours of the day between movement, resting and foraging.
The purpose of this study is to examine how frequently the young horses in a group housing system use the indoor lying area.
Social kontakt för hund i rastgård ? när kan kraven anses uppfyllda?
People in Sweden have more and more dogs in their care, and several of these dogs are kept in kennels in back yards for various reasons. According to Swedish animal welfare legislations the need for social contact for dogs has to be met. However, there are few details presented on how to meet the need and when it can be considered satisfied. Does the dog need human contact to fulfill the need, or is the company of other dogs enough? This study aims to specify what can be acceptable when it comes to fulfilling dogs? social needs in accordance with the Swedish animal welfare legislation.
Inter-species embryo transfer in South American camelids
Embryotransfer är en metod där ett embryo i tidigt stadium flyttas från en donator till ett mottagardjur som sedan bär dräktigheten till förlossning. Det innebär att donatorhonan kan donera flera embryon under en säsong då den vanligtvis endast skulle kunna producera en avkomma. Embryo transfer är således en metod för att snabba på det genetiska urvalet i en grupp djur. Bland de mycket ekonomiskt värdefulla alpackorna i Peru, där många av herdarna saknar alternativa inkomstkällor kan embryo transfer bidra till ett mer effektivt avelsarbete och i förlängningen en bättre levnadsstandard för alpackaherdarna och deras familjer. Studien beskriver ett experiment där ett protokoll för embryo transfer från alpacka till lama utförs under fältmässiga omständigheter på en forskningsstation i de peruanska Anderna.
Provtagning av trädkärnor för att bedöma föroreningsgraden av klorerade lösningsmedel i grundvatten
Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons.
Kaliumgödsling på torvmark - effekt på tillväxten hos planterade granar (Picea abies)
Peat lands are a great potential resource for increased forest growth in Sweden, there are approximately 6.5 million hectares of peat lands, whereof around 70% produce less wood than one m3sk/ha and year and are therefore classed as forest waste land. There are over 200 000 hectares of peat land that is already drained and wooded, and that may be suitable for fertilization. Forest production on peat soils usually requires drainage and fertilization. Dewatering requires ditching the area, so that the roots can have access to oxygen. Nitrogen is often abundant in the peat but other nutrients; especially potassium is in short supply. The purpose of this work was to examine the effects of potassium fertilization on the growth of spruces that were planted on drained peat land and how different amount of fertilizers affects the growth. Potassium deficiency is strongly growth inhibiting, since potassium is important for substance transport in the tree. Potassium is also important for the carbohydrate formation, and because increasing the sugar content of the cells constitutes a lower freezing temperature does potassium availability in the soil play a major role in the winter resistance of many species. Potassium is not found in any organic compounds in the tree, but is present in cell and tissue fluids. A fertilization trial was started in 1978 in Siljansfors Experimental Forest. The plots in the experiment were fertilized with different amounts of potassium and one plot was left without fertilization. All plots that were fertilized with potassium grew considerably better than the unfertilized plot. The difference in production between the unfertilized plot and the plot that received the most potassium was 7.2 m3sk/ha and year. The unfertilized plot can still be classified as waste land. The theoretical production capacity was estimated using a Swedish system for site quality estimation of wetlands after ditching (dikningsbonitering). The plot with most potassium produced after fertilizationaproximately in level with theoretical estimations. Key words: Peat land, Fertilization, Ditching, Growth, site quality..
Synchronizing migration with birth: an exploration of migratory tactics in female moose
Migration and giving birth are crucial decisions for animals during their life cycle, which may have lasting consequences on their population demography and fitness. Migration can entail a variety of possible effects for an individual, such as access to high quality food and reduced risk for predation. The moose (Alces alces) in northern Sweden is partially migratory and moose females are known to give birth to one or two calves. The synchrony between time of calving and timing of migration has not been compared before, especially in terms of energy maximizing and time minimizing perspectives, which may provide vital cues for fitness benefits of migration. I investigated effect of timing of birth and individual life history on distance, timing, stopovers and duration of 190 individually marked female moose that have been tracked for multiple years in ten different areas in northern Sweden.
Upprepad administrering av trimetoprim/sulfadiazin till neonatala föl : plasmaproteinbindning och effekt på serumbilirubinkoncentrationen
Today most dosages used in horse medicine are based on studies in adult horses. Since there are differences between adult and neonatal horses with respect to different pharmacological parameters this can cause problems when administring drugs to neonatal foals. Neonatal sepsis is a common cause of morbidity and mortality in foals and aggressive antibiotic treatment is needed immediately when sepsis is suspected. In Sweden the combination of trimethoprim/sulphadiazine and bensylpenicillin is often used as the initial treatment. When administering drugs, interactions can occur between the drugs and endogenous substances.
Djurskyddskontroller ur lantbrukarnas perspektiv - från kommun till länsstyrelse
On the first January 2009 the official animal welfare control were transferred from the municipalities to the County Administrative board. With this transition, some changes occurred for those who work as animal welfare inspectors. The aim for this study was to examine farmers' view on the transition between the municipalities and County Administrative board, in order to compare the two authorities. I have also studied the farmers view about animal welfare inspectors' knowledge, both theoretical and practical. The questionnaire also included questions about farmers' view on animal welfare legislation.
Inga miljövinster med ekologisk produktion? : Lägesrapport över den svenska jordbruksdebatten
Organic agriculture is financially promoted in Sweden by special environmental support and as consumers we are all encouraged to buy organic food. At the same time scholars at the Swedish University of Agricultural Sciences claim that organic farming does not provide any environmental benefits. The main criticism is that organic farming has lower yields than conventional, which means that more land is needed to produce the same amount of food as in conventional farming, leading to deforestation and loss of biodiversity. As for climate change, the critics claim that the significantly higher productivity in conventional crop production compared to organic, releases surplus land, which could be used for bio-fuel production and thereby replace the fossil fuels. The critics also claim that organic farming causes higher nutrient leaching than conventional.
Identifiering av fel i skogliga beståndsregister med hjälp av satellitdata :
This thesis has focused on the possibility to use a satellite image method developed by Metria Mijöanalys to identify stands that are wrongly registered in Holmen Skogs database. The method is only intended for identifying stand with poor descriptions in Holmen?s database that needs to be updated and not for updating the stand information.
The study area is located several km west of Hudiksvall on the borderline between Gävleborgs- och Västernorrlands län. The area is covered by a SPOT image from 2005. By which Metria Miljöanalys has made estimates of forest parameters for all stands in the area, and compared them with corresponding estimates according to the stand database.