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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.
51

Inventering av mångfalden av lavar i en produktionsskog jämfört med en barrblandskog

Gustafsson, Sigrid, Rolandsson, Nellie January 2023 (has links)
Lichens are complex organisms that can live at extreme places, at the same time they are important for several ecosystem services but also sensitive to forestry, air pollution and climate change. Something that several studies on lichens have concluded is that the lack of old trees or trees with a large circumference affects many species of lichens, and this is a consequence of today's forestry in Sweden. Since Småland has a high value of forests and is far ahead when it comes to revenue, it was interesting to investigate how epiphytic lichens are affected by this. The study was conducted in Härensås, a village that belongs to Växjö municipality. Two different forests were surveyed, a production forest with spruce and a mixed coniferous forest consisting mainly of pine and spruce. By comparing the species richness of epiphytic lichens in both forest types, we got the result that lichens are not only dependent on large and old trees, but are also influenced by the diversity of tree species in an area.
52

Health-hazardous Fungi in Feces from Feral Pigeons

Hermann, Elin January 2023 (has links)
The spread of pathogens by animals is a global issue that poses a significant threat to human health. The feral pigeon (Columba livia forma domestica) lives in cities near humans, where it nests, eats, and litters. The pigeons are known to be zoonotic carriers of several pathogenic fungi which can be transmitted to humans through contamination of air and water by their feces. This study aims to review the literature to determine which fungi from the World Health Organization’s (WHO) fungal priority pathogen list (2022) have been detected in pigeon feces and from which countries. Literature searches were conducted in PubMed and Web of Science in April 2023, where 32 papers comprised the results in this study. Among the fungal species listed by the World Health Organization (WHO), 11 of them have been reported in pigeon feces. The majority of studies focused on Cryptococcus neoformans and Candida albicans. All the 11 detected fungal pathogens can cause human diseases where immunocompromised and critically ill individuals are at a higher risk of serious infections. Thus, more information about the risk of exposure to feral pigeons is needed due to their pathogenic potential. Furthermore, it is important to deter pigeons from nesting in sensitive areas such as near hospitals. Population size of pigeons could also be controlled to improve their health and prevent the spread of pathogens. Most studies included in the results were conducted in countries located in South America, Africa, and Asia. There seems to be a limited number of studies investigating the fungi species on the WHO’s list and their global distribution is not extensively studied. Global research on the prevalence of the fungi species on WHO’s list is necessary to determine their health impact, especially as climate change might increase the distribution of pathogenic fungi.
53

Synen på förekomsten avhälsoproblem hos brakycefala hundar / Attitudes towards the presence of health problems in brachycephalic dogs

Van Den Weghe, Johannes January 2023 (has links)
The selective breeding of dogs (canis lupus familiaris) has a long history. Dogs thathave been bred to be brachycephalic are associated with a number of differenthealth problems such as breathing issues, problems with regulating bodytemperature and eye-, skin-, and dental disorders. A survey was used to comparedog breeder’s and clinical veterinarians’ attitudes to the prevalence of healthproblems in brachycephalic dog breeds. This study showed that there is a differencein the attitude towards health problems when comparing dog breeders andveterinarians. For most statements in the survey the dog breeders agreed to a lesserextent then the veterinarians to the health problems in their breed with the biggestdifference in the attitude towards eye-, skin- and dental disorders. This discrepancyin the answers in the survey indicates that dog breeders and veterinarians have adifferent standard for what they consider a health problem. In the long run thesedifferent standards risk to negatively affect the health of pedigree dogs.
54

Genetic and Experimental investigations of the pathogenicity of Sindbis virus genotypes.

Chandra Singh, Manish January 2020 (has links)
Sindbis virus (SINV) is a virus transmitted by mosquitoes. It has a wide geographical distribution covering most of Europe, Africa, Asia, Australia and New Zeeland. To date, six main different types of SINV are known (genotypes), but only genotype I (SINV-I) has been linked to human disease. SINV-I is present in Europe and Africa but has only been reported to cause outbreaks in northern Europe (Finland and Sweden) and South Africa. It is interesting to note that SINV does not cause any outbreaks in other parts of Europe or around the world; for example, no known cases have been observed in Germany. In this study, we aimed to characterize differences among SINV genotypes from different parts of the world, that can potentially explain why outbreaks of disease only occur in certain regions. This was done by full genome sequencing, as well as experiments where different SINV viruses were allowed to infect cells. The full genome sequencing will add to the existing knowledge about SINV genotypes and will help to establish a relationship between the divergence or the mutations associated with the SINV isolates. The experiments will help us understand the growth and infectivity of the different genotypes. Analysis of the sequencing showed that SINV formed five very distinct groups confirming earlier proposed division into genotypes. SINV isolates originating from Africa, Germany, Finland, and Sweden were all groped within one cluster. The result further supported the hypothesis that SINV-I was introduced to northern Europe from Central Africa. We compared the similarity of nucleotides and amino acids for all proteins coded for by the virus, and they showed high levels of similarity within genotypes as well as in between genotypes, with certain point-mutations in nucleotides and few amino acid substitutions in peptide sequences. In our growth experiments, we found considerable differences in the growth pattern of SINV genotypes. SINV-I strain from Germany followed the growth pattern of SINV-I strains from Finland and Sweden which are associated with causing the disease. Interestingly, even though on a molecular level SINV-II and SINV-III seemed to be similar, they differ in their growth rate and how much infectious virus particles they produce. These findings were very interesting because, to date, there are no human cases of SINV infection in Germany, and the antibody prevalence in the human population is 0,1% as compared to 3% in Sweden and 5.2% in Finland. Our results suggest that the German SINV strain is not less infectious than the Swedish and Finnish strains, thus the absence of cases and low antibody prevalence in Germany is likely to be due to other factors than the virus itself. Such factors could be related to the transmission ecology, meaning that the virus might not be transmitted as efficiently in central Europe as in the north. One suggested reason is that the vector mosquito species (Culex torrentium) that most efficiently transmit SINV is less common in central Europe than in the north.
55

Våtmarker i Mariestad : Restaurering, åter- eller nyetableringspotential? / Wetlands in Mariestad : Potential of restoration, re- or new establishment?

Bjurén, Jenny January 2023 (has links)
Antropocena aktiviteter har påverkat både terrestra och akvatiska livsmiljöer negativt under de senaste århundradena. Världens våtmarker har sedan 1700-talet minskat med 90% och Sverige är inte undantaget trenden med minskade arealer. Genom restaurerings- eller etableringsåtgärder kan denna trend bromsas. Inför framtagande av lämpliga restaurerings- eller etableringslokaler ska våtmarkens tilltänkta ändamål specificeras. För detta projekt är syftet att identifiera lokaler där restaurering, återetablering eller nyetablering kan bidra positivt till biodiversiteten, både lokalt inom Mariestad och regionalt i Västra Götaland. Vidare är syftet också att undersöka om dessa objekt kan få positiva effekter för näringsretention. Parametrar med avsikt att synliggöra gynnsamhet för biodiversitet respektive näringsretention användes i analyser inom Geografiskt informationssystem (QGIS). Värden som dessa analyser genererade sattes samman till ett biodiversitetsindex samt ett näringsretentionsindex som sedan genomgick kategorisering för framtagande av de mest gynnsamma lokalerna. Ett slumpat urval av dessa besöktes även i fält. Resultaten visar att våtmarker inom Mariestad minskat sedan 1800-talet. Vid jämförelse av täthet synliggjordes dessutom att våtmarker lokaliseras glesare inom kommunen (0.099/km²) än för länet i stort (0.127/km²). Därtill uppdagades att objekt kunde ”dubbelklassas” vilket innebar att objekt inom de mest gynnsamma kategorierna för biodiversitet även kunde hamna inom motsvarande kategorier för näringsretention. Vilket indexvärde som bör väljas för att gynna biodiversitet mest är dock invecklat eftersom biodiversitet både kan gynnas eller missgynnas av förhöjda näringshalter. Dock kan fokus på näringsretention gynna biodiversitet för Mariestads del på grund av recipienter som bör skyddas från näringsläckage. ”Dubbelklassade” objekt kan därav vara mest gynnsamma för kommunen att fokusera på. / In recent centuries anthropocene activities have negatively affected both terrestrial and aquatic habitats. Wetlands of the world have decreased by 90% since 18th century and Sweden is not an exception from this trend of reduced areas. To restrict this trend wetland restoration, or establishment, can be implemented. This is advantageously done by specifying the intended purpose of the wetland, before measures are carried out. This project aims to identify locations with positive auspiciousness for biodiversity or nutrient retention both locally within Mariestad and regionally in Västra Götaland. Parameters that would display the favorability of biodiversity (and nutrient retention respectively) were used within Geographical Information System (QGIS). The values generated from these analyzes were compiled into a biodiversity index (and a nutrient retention index). These underwent categorization to produce the most favorable locations. A random selection of these was also visited. The results show that wetlands within Mariestad has decreased since the 19th century. When comparing density, it was shown that wetlands are located more sparsely within the municipality (0.099/km²) than for the county (0.127/km²). Further, objects could be "double-classified", which meant that objects in the most favorable categories for biodiversity also could be in the corresponding categories for nutrient retention. It’s a complex matter to choose which index value that would benefit biodiversity the most. Biodiversity can both benefit and be disadvantaged by increased nutrient levels. However, focus on nutrient retention can benefit biodiversity for Mariestad due to reduced leakage. "Double-classified" objects can therefore be favorable for the municipality.
56

Investigation of the interaction of A-MYB and TCFL5 on pachytene PIWI-interacting RNA genes in two sub-species of mice, mus musculus musculus and mus musculus castaneus

Banu, Most Shova January 2023 (has links)
Spermatogenesis is a complex process that involves the production of sperm cells from germ cells in order to transmit genetic information to progeny. The PIWI-interacting RNA (piRNA) is a non-coding small silencing RNA that guides the PIWI protein to silence target transposon transcripts to regulate the production of germ cells. In mammals, distinct sets of piRNAs function in gonocytes, spermatogonia, and developing spermatocytes. Coinciding with puberty, pachytene piRNAs, expressed at pachytene stage of meiosis I, silence mRNAs to regulate spermatogenesis. At the onset of meiosis I, the transcription factors A-MYB and TCFL5 initiate the transcription of pachytene piRNA genes via binding to their transcription start sites. This study aims to detect which pachytene piRNA genes are bound by these two transcription factors in two sub-species of mice, Mus Musculus musculus and Mus Musculus castaneus, and if there is a variation in binding regions between these sub-species. Here, chromatin immunoprecipitation followed by sequencing (ChIP-seq) was performed to map the binding regions of A-MYB and TCFL5 in the genomes of mouse sub-species. Three testis tissues from each sub-species were sonicated for ChIP-seq on A-MYB and three from each mouse for TCFL5. Sonication was optimized at high power for 40 cycles of 60 sec on, 30 sec off, for 1 h. After 20 cycles, lysates were transferred to a fresh tube, vortex, and sonicated for 20 more cycles. Library DNAs were average 333-360 bp, and qPCR showed enough DNA for Illumina sequencing. Analysis of sequencing data is ongoing. The transcription start sites of pachytene piRNAs could be identified after analysis.
57

New Birkeniid Anaspid from the Silurian of the Canadian Arctic

Su, Ruiying January 2022 (has links)
No description available.
58

Size range analysis of an early actinopterygian assemblage from East Greenland

Li, Jixiang January 2022 (has links)
No description available.
59

Identifiering av LPS-bindning till cellytor hos olika blodkroppstyper i sötvattenskräfta

Eriksson, Linnea January 2023 (has links)
Both vertebrates and invertebrates use an innate system to recognise and fight pathogens such as bacteria. In this study, I focus on the methods the freshwater crayfish Pacifastacus leniusculus possess to inhibit the Gram-negative bacteria via LPS-recognition. Previous research has shown that this crayfish has certain proteins that can bind LPS, and that its bloodcells, the haemocytes, have an important role in this. However, scientists have yet to find evidence that LPS can bind the outside of these cells, similar to LPS-binding in humans. By bleeding crayfish and treating the cells with a primary and secondary antibody I could observe LPS-binding to the outside of granular haemocytes. This suggests there might be a protein positioned in or on the membrane of these types of cells that can bind LPS, which initiates the defence mechanisms.
60

DINCH and DINP Plasticizers Alter Lipid Metabolism in 3T3-L1 cells

Häggblom, Isabel January 2022 (has links)
Di(isononyl)cyclohexane – 1,2 dicarboxylate (DINCH) and Diisononyl phthalate (DINP) are high molecular weight compounds used as plasticizers. DINCH and DINP use on the market have been increasing recently to replace previously used phthalate plasticizers in polymeric products. Exposure to the compounds DINCH and DINP has been shown to be targeting the adipose tissue and potentially inducing lipid metabolism. However, few studies have reported the potential toxicity of these plasticizers and in this study, their effect on the 3T3-L1 cell line was investigated. The preadipocytes 3T3-L1 cell lines were exposed to 1 μM, 10 μM, and 100 μM DINCH and DINP for 10 days and assessed by lipid accumulation, gene expression, and protein analysis. The result of the lipid accumulation showed that higher concentrations of DINCH and DINP can induce adipogenesis. The proliferator-activated receptor gamma (Pparγ) agonist Rosiglitazone (Rosi) was used as a positive control. Further, the result of DINCH and DINP on gene expression showed that these compounds can both upregulate and downregulate genes involved in adipogenesis. The plasticizers DINCH and DINP upregulated proliferator-activated receptor-gamma and alpha (Pparγ, Pparα), CCAAT/enhancer-binding protein alpha (C/EBPα) and the fatty acid-binding protein 4 and 5 (Fabp4, Fabp5) and downregulated Fatty acid synthase (Fasn) and Gata binding factor 2 (Gata2) transcript levels. Protein analysis using Western blot showed that both DINCH and DINP can downregulate FASN protein expression. From this study, it can be concluded that DINCH and DINP influence the metabolic pathways and this can be a serious threat to animals and humans as the use and their levels in the environment are increasing.

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