Comparative morphometric and molecular genetic analyses of triatominae (Hemiptera: Reduviidae)

Triatomine bugs (Hemiptera: Reduviidae: Triatominae) are the vectors of Chagas disease in South and Central America. Chagas disease predominantly affects poor rural communities with simply constructed housing susceptible to infestation by triatomines. Chagas disease is restricted to the Americas largely due to the limited distribution of triatomine bugs. The global diversity of triatomines is -130 species, of which only -10% are known to occur outside the Americas, one species (Triatoma rubrofasciata) is tropicopolitan, and the others are concentrated on the Indian subcontinent (Linshcosteus spp. ) and adjacent south east Asian island groups (Triatoma spp. ). The main objectives of this PhD programme were to: a) assess the facility of morphometric approaches (measurement and robust statistical analysis of morphological variation) in the study of population structure of vector species with proximal domestic and silvatic distributions to detect population structure and give information on the risk of reinvasion, b) study interspecific and higher taxonomic level relationships of New World and Old World triatomine bugs. To these ends geometric morphometric analyses were conducted in concert with molecular genetic analyses of mitochondrial and nuclear DNA sequences. The principal question being: Does the relatively low cost method of morphometrics reveal patterns consistent with population structure, as otherwise determined by more expensive molecular genotyping methods? Or are such patterns disrupted by environmental effects and intraspecific convergent/divergent morphological evolution? Combined morphometrics and molecular genetics were used to study vector populations in three of the countries that continue to be most affected by Chagas disease. In Venezuela and Ecuador Rhodnius species (R. prolixus and R. ecuadoriensis respectively) were studied, in areas where they occur in both domestic and silvatic environments, and in Paraguay T. infestans from a domestic and a putative silvatic focus. Head and wing morphometrics were compared to mitochondrial DNA sequence data to assess the population structure and disparity among domestic and silvatic samples in each case. The results presented suggest that head shape variation is subject to morphological plasticity and/or selective pressure and functional constraint and does not correlate well with the 11 Abstract phylogeny. However, in all examples, wing shape was found to be congruent with the phylogenetic patterns inferred from sequence analysis. Consequently, it is recommended that wing shape and not head shape be used in morphometric assessments of population dynamics. It is also asserted here that if population structure is suggested by morphometrics, it should be followed by robust population genetic analysis. As such, morphometrics could be used as a tool for broad surveillance to identify areas of concern. A further objective was to elucidate the broader phylogeny of Triatominae and their relationships with other reduviid subfamilies. To investigate the debated polyphyletic origin of the Triatominae molecular approaches were used. Combined head and wing morphometric and molecular genetic analyses of New World and Old World Triatominae have revealed patterns of convergent morphological evolution (among New World and Old World Triatoma) and striking examples of strongly divergent morphological evolution (between Old World Triatoma and Linshcosteus). Applying a molecular clock based on the rate of sequence divergence for a fragment of ribosomal DNA (D2-28S), calibrated to the fossil record and vicariant events (the divergence of ancestral lineages due to separation by topographical or ecological barriers) it has been possible to reconstruct a likely evolutionary history for the Triatominae and the Reduviidae as a whole. The weight of evidence presented supports a polyphylectic origin for blood-feeding for the Triatominae. The apparent independent development of blood feeding among the main lineages of the Triatominae represented by the genera Triatoma and Rhodnius highlights a fundamental biological difference among important vector species. This difference is likely to become evident in the eventual post genomic era in studies of vector/parasite interactions and it highlights the importance of sequencing genomes from different vector genera.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Allergifritt boende genom val av invändiga ytmaterial

The number of people of getting allergic symptoms is increasing and the reasons are considered to be many. The human have changed their habits and spend more time indoor. In combination with new building technologies where denser housing constructions and new materials this causes bad indoor climate contributes to a higher occurrence of allergies There are several courses of action to deal with this problem. One action is by choosing allergy-free interior surface materials. An allergy-free material emits low concentrations of harmful substances resulting in a great indoor air quality. An allergy-free living demands a frequently cleaning and resistant material are required. As a consumer today, it is difficult to assess how allergy-friendly building materials are and the national requirements. The report summarizes the most common types of surface materials and their properties of functioning and emissions. Emissions are releases of harmful substances from the material. The harmful substances studied are VOC's, formaldehyde and phthalates. The studies have shown that there is small amount of available information about allergy-friendly materials. There are general guidelines in "Svenska miljömålen", "Boverkets byggregeler" and "Kemikalieinspektionens föreskrifter". The guidelines are difficult to apply when there is no information about specific properties of materials. It is possible to note how suitable different types of materials are relative to each other. The materials considered appropriate in an allergy-free living are a base of gypsum board and finishes of tiles and plain wallpaper. When selecting materials, it is important to consider in what environment material is used and what factors might affect it. Some materials may degrade properties while get in contact with moisture. Increased moisture increase emission of harmful substances and therefore sensitive materials should be avoided in environments with high moisture. For consumers to make informed choices of allergy-friendly surface materials a classification system is needed. For this to be applicable building materials should be labeled by this classification system

Numerical simulations of concrete slabs on grade with gradient shrinkage and reinforcement for crack control

Betongplattor på mark är en ofta använd grundläggningsmetod. Trots detta är sprickbildning ett vanligt problem där kraven på maximala sprickvidder ofta inte uppfylls. De sprickor som bildas i plattorna uppkommer bl.a. till följd av dess uttorkning, och då olika fuktförhållanden råder på var sida om plattan utvecklas en krympning som varierar med en gradient över tvärsnittet. Vid dimensionering av armeringen för denna inre last och sprickbildningen den orsakar, finns endast otillräckliga analysermetoder att tillgå i normer. Att analysera det tvång som uppstår vid krympningen är mycket svårt, speciellt då betongen spricker och lastfallet blir statiskt obestämt. I detta arbete undersöks sprickbildningen i krympande betongplattor på mark så att noggrannare dimensionering av den sprickfördelande armeringen skall kunna utföras. Analyserna har utförts med numeriska simuleringar i FEM-programmet Atena 2D där ett antal olika plattor med varierande betongklass, armeringsinnehåll och platthöjd undersökts. Arbetet omfattar en jämförelse av de erforderliga sprickfördelande armeringsinnehållen samt de analytiskt beräknade sprickvidder som erhålls dels enligt huvuddokumentet för Eurokod 2 och dels enligt huvuddokumentet och den tyska nationella bilagan. Armeringen har då dimensionerats utifrån en spänningsfördelning som varierar linjärt över tvärsnittet, på samma sätt som krympningen varierar. Studien behandlar även en jämförande undersökning av sprickutvecklingen vid inre respektive yttre last för att påvisa skillnader i sprickbeteendet. De numeriska simuleringarna visade att en ökad sprickfördelande förmåga och en minskning av sprickvidder erhålls då armeringsinnehållet i en platta ökas. Av de undersökta plattorna nås armeringens flytspänning inte i något fall, vilket tyder på att mängden armering kan minskas ytterligare utan att s.k. single cracks uppstår. Även vid underarmering, då armeringen minskas till 64 % av vad Eurokods huvuddokument anger, behålls den sprickfördelande funktionen. Undersökningarna visade att den sprickbildning som sker av den inre lasten vid krympning är beroende av uppsprickningen, till skillnad från sprickbildning vid yttre last. Den jämförande studien över armeringsinnehåll enligt Eurokod 2 visar att dimensionering enligt tyska nationella bilagan under verkan av inre last ger en reducerad erforderlig armeringsarea med 20 % i förhållande till huvuddokumentet. De analytiska beräkningarna över sprickvidder tyder på att beräkningsmetoden enligt Eurokod 2 ger större sprickvidder än den som beräknats enligt den tyska nationella bilagan

Identification of genetic markers influencing rheumatoid arthritis susceptibility and severity

Rheumatoid Arthritis (RA) is a chronic inflammatory disease characterized by progressive joint inflammation that results in bony erosions and cartilage damage. Until recently only 2 genes were unambiguously correlated with disease risk: the HLA-DRB1 and the protein tyrosine phosphatase non-receptor 22 (PTPN22). Several genome wide scans conducted in populations from UK, USA and Sweden have suggested other risk loci including TNFAIP3-OLIG3, TRAF1-C5 and STAT4. The search for genetic regions associated with complex diseases such as RA is an important challenge that could lead to better diagnosis and treatment directed at the cause of the disease.EThOS - Electronic Theses Online ServiceGBUnited Kingdo