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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Effects of a fish farm on downstream macroinvertebrates

Thoresson, Joakim January 2018 (has links)
The number of fish farms is increasing worldwide tomeet the global demand for fish used as a food source for humans. The WorldBank predicts that by 2030, 62 percent of all consumed fish globally will beproduced in fish farms. Due to this increasing demand for fish, fish farming isa growing business and the numbers of fish farms are increasing. Today, thereare fish farms situated in more than one hundred municipalities in rural partsof Sweden. Fish farms may besituated in hydropower plant reservoirs, which have been foundto be suitable locations for cage fish farming. However, environmental concernshave been raised regarding excess dissolved nutrients from fish farms thatmight enrich downstream ecosystems. The source of this enrichment is primarilyfish feces and uneaten fish feed, which contain both nitrogen and phosphorus. The overall objective of this study is to evaluate the effects of a largefish farm located in north-central Sweden on the downstream river ecosystem. Todo this, I compared benthic macroinvertebrate diversity, functional feedinggroup representation, community composition, and indices of biotic integritybetween a site downstream of a fish farm and a nearby (control) reach withoutan upstream fish farm. No significant difference between these sites wasobserved for any metric accept for the species richness, but due to the lowreplication results should be interpreted with caution. Further studies areneeded to assess the possible impact of fish farms on the water quality andecological health of rivers.
242

Relation between herbivore abundance, herbivore diversity and vegetation diversity

Lundgren, Andreas January 2018 (has links)
No description available.
243

Investigation of developmental neurotoxic effects of exposure to a combination of methylmercury and chlorpyrifos

Forslund, Annica January 2018 (has links)
No description available.
244

Hur uppfattar elever på naturvetar-programmet visualiseringar inom ämnet biologi?

Svensson, Thomas January 2018 (has links)
Detta avslutande självständiga arbete handlar om visualiseringar i undervisningen inom naturvetarprogrammet och då främst inom ämnet biologi på gymnasiet och då främst avseende hur eleverna upplever användningen av visualiseringar i undervisningen. Bakgrunden till detta arbete är att i undervisningen inom biologi ska eleverna enligt Skolverkets läroplan Lgr 11 få möjligheten att utveckla förmågan att ”… använda kunskaper i biologi för att kommunicera samt för att granska och använda information.” Modeller och begrepp som är centrala i undervisningen anges i centrala innehållet inom respektive kurs i biologi och bl.a. cellen och cellers egenskaper, funktioner och kommunikation, cellmetabolism, ekosystem, evolutionen, fotosyntesen, livscykler, människan och andra organismers fysiologi ska ingå (Skolverket, 2011a). I Sverige har vi ett flertal forskare som forskar kring visualiseringar i undervisningen med olika inriktningar och jag har försökt att belysa delar av deras forskning i min bakgrund till uppsatsen för att försöka sätta in läsaren i forskningen kring olika former av visualiseringar. Flera av dessa forskare inriktar sin forskning till områden som berör ämnet biologi i stort. Syftet med arbetet var att försöka ta reda på elevers erfarenheter av användningen av visualiseringar genom två enkätundersökningar. Enkätundersökningen har, främst, fokuserat på hur visualiseringar används inom ramen för biologiundervisningen på naturvetarprogrammet på gymnasiet och hur eleverna upplever detta. Frågeställningarna i enkätundersökningen var: Hur uppfattar eleverna användningen av visualiseringar i undervisningen, med tyngdpunkt på ämnet biologi, på naturvetarprogrammet? Hjälper visualiseringar i undervisningen på naturvetarprogrammet eleverna i deras lärande, enligt eleverna själva? En tredje fråga som fick sitt svar under processens gång utan att ha varit en fråga som arbetet tog sin utgångspunkt i, utan var en fråga i enkäten var: Hur anser eleverna att man bör följa upp visualiseringar i undervisningen? Jag fann att eleverna till stora delar upplever att de är hjälpta av visualiseringar i undervisningen.
245

Organic carbon getting buried deep: A study on a subtropical reservoir and comparisonwith a chain of reservoirs.

Åkerman Fulford, Emma January 2017 (has links)
Anthropogenic emissions of greenhouse gases are widely known to have damaging effects on the world’s environment. In the search for green energy, recent studies propose that hydropower, which is considered a renewable source of energy, contribute significantly to the emissions of carbon dioxide and in particular methane gas to the atmosphere. Hydropower dams can globally act as an important carbon source, however they can bury substantial amounts of carbon and simultaneously act as net carbon sinks. The main objective of this study is to determine, with high spatial resolution, OC burial in a tropical reservoir, Camargos, Brazil, and compare data with two reservoirs downstream to see if there is any effect of multiple damming. This master’s thesis included field studies in terms of sub-bottom profiling and sediment coring. This was followed by data analysis and mapping of seismic survey data as well as lab work including organic carbon content analysis, C:N ratio and particle size calculations in order to estimate sediment characteristics. The results propose that there is significant burial of organic carbon in Camargos reservoir, of 57.7 g C m-2 yr-1 and 121.3 g C m-2 yr-1 by sub-bottom data and individual coring respectively and evidently, reservoirs further upstream tend to accumulate more sediment and have a higher rate of OC burial. More precisely, the sub-bottom data indicate a steady decrease in OC burial rates of approximately 20%, per dam following the cascade of reservoirs downstream. However, in order to rely on hydropower as a sustainable renewable source of energy to meet the demands of a world wide growing population and economy it is essential to continue studying this topic to fully understand all aspects of the carbon processes within these systems and whether they function as substantial net sinks or sources. / Minor field studies / HYDROCARB- European Research Council
246

Kan man förutsäga biologisk mångfald i en livsmiljö utifrån livsmiljöns fördelning i ett landskap? : En teoretisk variabels förmåga att uppskatta biologisk mångfald testad mot empirin / Is it possible to predict biological diversity in a habitat based on the distribution of habitat in the landscape? : The ability of a theoretical variable to estimate biodiversity tested against empiricism

Gyltman, Frida January 2019 (has links)
Biologisk mångfald är en förutsättning för leverans av ekosystemtjänster vilka utgör en viktig resurs för människan. Idag förekommer ett antal hot mot den biologiska mångfalden varav förlust och fragmentering av habitat räknas till de största. Modeller för att uppskatta biologisk mångfald på landskapsnivå är således viktiga verktyg i bevarandebiologi och vid planering av grön infrastruktur. Detta examensarbete är en studie kopplat till ett pågående forskningsprojekt vid högskolan i Skövde som finansieras av Naturvårdsverket där syftet är att ta fram en ny biodiversitetsindikator på landskapsnivå; Landscape Biodiversity Capacity Index (LBCI). I detta examensarbete prövades en av LBCI:s teoretiska variabler med korrelationsanalyser mot empiriska data från landmiljön betesmark i Sverige för att utvärdera dess förmåga att göra teoretiska uppskattningar mot empirin. Variabeln som testades var Biotope Functional Capacity (BFC). Testerna utfördes genom att i södra och mellersta Sverige slumpa 20 replikat ifrån vilka empiriska data erhölls från betesmarker genom Nationell Inventering av Landskapet i Sverige (NILS). Den empiriska datan sammanställdes i fyra olika diversitetsindex; artantal, Shannons index, Simpsons index of diversity och Simpsons reciprocal index. Avslutningsvis utfördes statistiska korrelationsanalyser vilka inte påvisade någon korrelation mellan BFC och diversitetsindexen. Orsaker till detta kan bland annat bero på hur den empiriska datan har analyserats och sammanställts eller brister i variabeln BFC. Denna studie har trots det bidragit till viktiga synpunkter vid den fortsatta utvecklingen av den nya biodiversitetsindikatorn LBCI och metodutveckling för att i fortsättningen undersöka samband mellan variabeln BFC och empiriska värden. / Biodiversity is a prerequisite for the delivery of ecosystem services, which constitute an important resource for man. Today, there are several threats to biodiversity, of which loss and fragmentation of habitats are among the largest. Models for estimating biodiversity at the landscape level are thus important tools in conservation biology and in green infrastructure planning. This thesis is a study linked to an ongoing research project at the University of Skövde, which is financed by the Swedish Environmental Protection Agency. The aim is to develop a new biodiversity indicator at the landscape level; Landscape Biodiversity Capacity Index (LBCI). In this thesis, one of LBCI's theoretical variables was tested whether it correlates with empirical data from the pastoral land in Sweden in order to test its ability to make theoretical estimates against the empiric. The variable tested was Biotope Functional Capacity (BFC). It was done by sampling 20 replicates in southern and central Sweden from which empirical data were obtained from pastures through the National Inventory of the Landscape in Sweden (NILS), compiled into four diversity indexes; species richness, Shannon's index, Simpson's index of diversity and Simpson's reciprocal index. Lastly, statistical correlation analyzes were performed which did not show any correlation between the variable and the various diversity indices. Reasons for this may be due to how the empirical data has been analyzed and compiled or deficiencies in the BFC variable. Nevertheless, this study has contributed to important viewpoints in the continued development of the new biodiversity indicator LBCI and method development to further investigate the relationship between the BFC variable and empirical values.
247

Att arbeta med sex och samlevnadsundervisning : En undersökning om ämnesövergripande samarbeten och svårigheter att undervisa i ett ämne utan tydliga ramar

Vinberg, Janni January 2020 (has links)
No description available.
248

Identification of mRNA expressions as biomarkers of environmental pollutants in the great pond snail (Lymnaea stagnalis)

Eriksson, Johanna January 2022 (has links)
The great pond snail, Lymnaea stagnalis is considered a sensitive species to environmentalpollution and is used in ecotoxicology testing. The snail is naturally found in the environment inthe Holarctic realm in Europe, northern America and Asia but also in some parts of Australia. Itis a species of great interest for ecotoxicology studies and is used in research where commonendpoints are reproduction, mortality and immune responses. In this study we wanted to establisha method of using gene expressions in L. stagnalis as biomarkers of chemicals and pollutants inSTP effluent water. The study was conducted in two different experiments where gene expressionfor elongation factor 1a (ef1a), nuclear hormone receptor 3d (nr3d), cytochrome p450 3 (cyp3),metallothionein (mt), catalase (cat), glutathione peroxidase (gpx), and yolk ferritin (yf) from thehepatopancreas of L. stagnalis were measured. In experiment 1, animals were exposed tocadmium, 17α-ethinylestradiol, diclofenac, tramadol, PCB and a solvent control for seven days.In experiment 2 one group of animals were exposed to regular STP effluent water (UT), onegroup exposed to regular STP with an additional treatment of ozone (OZ), one group exposed toregular STP with an additional treatment of granulated active carbon (GAC) and finally, one lastgroup exposed to tap water (KV) as a control. The exposures lasted three weeks. In experiment 1,yf was upregulated 1.4-fold in snails exposed to PBC. In experiment 2, differences between thewaters were seen in the expressions of cyp3, gpx and yf. The expression of cyp3 was lower in theGAC group compared to the other groups. There was a difference in the expression of gpxbetween GAC and OZ but not compared to regular effluent water, UT or the tap water, KV. Theexpression of yf was higher in KV, but not different between the other groups. In summary, the yfgene expression in L. stagnalis is altered by PCB. There were also measurable effects of theexpression of cyp3 and gpx in snails exposed to effluent water treated with GAC. Conclusions ofthe results are difficult to draw but the changes in gene expressions indicates that L. stagnalis is apromising candidate as a model organism to gene expressions as biomarkers. Further studies arehowever needed to refine the method.
249

Positiva välfärdsindikatorer avseende beteendet hos sällskapskaniner : -vilka är kända och tar nuvarande djurskyddslagstiftning hänsyn till dem?

Nilsson, Marcus January 2021 (has links)
Historically, welfare assessments have focused on indicators of reduced welfare. However, positive welfare indicators in animals have recently captured the interest of researchers, animal owners and the general public. Regarding the behavior of pet rabbits, there are several positive welfare indicators described in scientific articles. There are for example expressions of joy in the form of so-called "binkies" and "zoomies", social rabbit companionship and what is called "allogrooming", exploratory behavior and a couple of different kinds of resting positions when the rabbit obviously feels relaxed, safe and secure. The Swedish animal welfare legislation would need to be adjusted to ensure that companion rabbits can display the behaviors that are classified as positive welfare indicators. Even if rabbits are kept in hutches with approved sizes, access to larger areas is required in order for several of the positive welfare behaviors to be expressed. In addition, today it is far too easy to circumvent the requirement for rabbit companionship. From an animal welfare point of view, it would also be advisable to call for supervision and attention more than just once a day. Given how common but complex pet rabbits are, more research is needed on their behavior and welfare needs, but also more information and knowledge for both current and future rabbit owners.
250

A SYK-dependent activation of STAT1-IRF1 amplifies the IFN signaling in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP)

Cuellar-Giraldo, David January 2018 (has links)
No description available.

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