Dissertations / Theses on the topic 'Spatial host population structure'
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Kendrick, Gary. "The epiphyte Microcladia coulteri (Rhodophyta) : changes in population structure with spatial and temporal variation in availablity of host species." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/25881.
Full textScience, Faculty of
Botany, Department of
Graduate
Appelgren, Anais. "Evolutionay consequences of the population structure of an ectoparasite at different spatial scales : an empirical approach of the hen flea-passerines system." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10296/document.
Full textDivergent evolution is a key process generating biodiversity. This can occur between localities, through reduced gene flow followed by local adaptation or genetic drift, and within localities through ecological specialization. In the case of multi-host parasite systems, adaptation can be driven by the relative rate of host-parasite gene flow among spatially isolated populations, and the amount of parasite exchange among local host types. Combining population genetics and field experiments, we examined how adaptation and genetic isolation shape parasite evolution. Focusing on the hen flea Ceratophyllus gallinae, a presumed host generalist, and two of its hosts, the great tit Parus major and the collared flycatcher Ficedula albicollis, we investigated parasite population structure and adaptation within a fragmented landscape. Additionally, we tested how hosts can influence encounter rates with specialized flea populations through their habitat choice. Neutral markers analyses show that flea populations are genetically differentiated at fine spatial scales, and frequently between the two host species. Evidence for parasite adaptation to each host type were also observed. Host specialization may therefore be ongoing in hen fleas. However, birds did not show specific habitat choice strategies regarding flea-infested nests. Host responses differed between two replicate sites, indicating that local population history may impact parasite evolution. Both isolation and host-based selection are therefore acting on hen flea populations at a local scale. Investigations in new localities will help to assess to what extend this divergent evolution may generate biodiversity
Henri, Dominic Charles. "From individuals to ecosystems : a study of the temporal and spatial variation in ecological network structure." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15726.
Full textBrouard, Vianney. "Cell dynamics of multitype populations in oncology and Invasion probability of cooperative parasites in structured host populations." Electronic Thesis or Diss., Lyon, École normale supérieure, 2024. http://www.theses.fr/2024ENSL0037.
Full textThis thesis focuses on the study of two stochastic models related to medical problems. The first one lies on understanding infection spread of cooperating bacteriophages on a structured multi-drug resistant bacterial host population. Motivated by this example, we introduce an epidemiological model where infections are generated by cooperation of parasites in a host population structured on a configuration model. We analysed the invasion probability for which we obtain a phase transition depending on the connectivity degree of the vertices and the offspring number of parasites during an infection of a host. At the critical scaling, the invasion probability is identified as the survival probability of a Galton-Watson process. With the aim to get a biological more relevant model, we analysed a similar model where a spatial structure is added for the host population using a random geometric graph. We have shown that such spatial structure facilitates cooperation of parasites. A similar phase transition occurs where at the same critical scaling the invasion probability is upper and lower bounded by the survival probabilities of two discrete branching processes with cooperation. The second medical question deals with understanding the evolution of the genetic composition of a tumor under carcinogenesis, using multitype birth and death branching process models on a general finite trait space. In the case of neutral and deleterious cancer evolution, we provide first-order asymptotics results on all mutant subpopulation sizes. In particular such results capture the randomness of all cell trait sizes when a tumor is clinically observed, and mostly it allows to characterize the effective evolutionary pathways, providing information on the past, present, and future of tumor evolution.Moving beyond this restrictive neutral and deleterious cancer evolution framework, we provide a new method to understand the first selective mutant trait size
Vogwill, Tom. "The ecology and evolution of host-parasite interactions in spatially structured populations." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533910.
Full textPurves, Drew William. "Local spatial structure and plant population dynamics." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251813.
Full textHamid, Mohd Norowi. "The analysis of host-parasitoid relationships at various spatial scales." Thesis, University of Greenwich, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267350.
Full textCheshire, J. A. "Population structure and the spatial analysis of surnames." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1324522/.
Full textPenington, Sarah. "Branching processes with spatial structure in population models." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:361e5c58-e6dd-47a0-9a52-303e897547e8.
Full textSurendran, Anudeep. "Stochastic and continuum descriptions of population dynamics with spatial structure." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/207574/1/Anudeep_Surendran_Thesis.pdf.
Full textYin, Mingbo. "Population structure and host-parasite interactions in the Daphnia longispina hybrid complex." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-137838.
Full textKing, Rachel, and n/a. "Spatial Structure and Population Genetic Variation in a Eucalypt Species Complex." Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20050113.091713.
Full textKing, Rachel. "Spatial Structure and Population Genetic Variation in a Eucalypt Species Complex." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/365496.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Full Text
Hopkins, Skylar R. "Multi-scale Transmission Ecology: How Individual Host Characteristics, Host Population Density, and Community Structure Influence Transmission in a Multi-host Snail Symbiont System." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/85567.
Full textPh. D.
Gordon, David M. "Population dynamics of a host-parasitoid system with particular reference to age-structure effects." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75358.
Full textSemeao, Altair Arlindo. "Spatial distribution, dispersal behavior and population structure of Tribolium castaneum herbst (Coleoptera: tenebrionidae)." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/7135.
Full textDepartment of Entomology
James F. Campbell
Phillip E. Sloderbeck
Robert "Jeff" J. Whitworth
Knowledge of factors influencing the establishment, persistence and distribution of stored-product pests aids the development of effective Integrated Pest Management (IPM) programs in food storage and processing facilities. This research focused primarily on Tribolium castaneum, which is one of the most important pests of mills. Populations of T. castaneum from different food facilities can potentially be interconnected by either their own dispersal behavior or by human transportation. Population genetic structure analyses based on microsatellites and other insertion-deletion polymorphisms (“indels”) showed that populations from different mills around the US are genetically distinct from each other, but the level of differentiation was not correlated with the geographic distance. A potential source of insect infestation within a food facility is spillage that accumulates outside or movement from bulk storage facilities on site. Results from three facilities showed that most stored-product species were captured both inside and outside buildings, but T. castaneum was rarely captured outside of the facilities. Spatial distribution of all species outside was associated with the proximity of buildings, not necessarily with areas with accumulated spillage. T. castaneum populations inside facilities are potentially exposed to frequent genetic bottlenecks resulting from structural fumigations. Changes in allele frequencies through time, based on the analysis of microsatellites and other indels in individuals collected in a mill, confirmed bottleneck effects. To understand how spatial distribution of T. castaneum within a mill could be influenced by environmental and physical factors, a range of variables were measured at each trap location. There was significant variation among trap locations regarding beetle captures and the variables measured, but increase in beetle captures correlated only with increase in temperature and spillage production. Tribolium castaneum response to visual cues could influence attraction to pheromone and kairomone olfactory cues used in traps. Results of laboratory experiments showed that adults respond to tall narrow black shapes and placing traps in front of these shapes can increase captures. This research provides new insights into factors influencing the spatial distribution of T. castaneum and could help in improving monitoring programs for this important pest of the food industry.
Moore, Catrin Elisabeth. "Case-control study of invasive Staphylococcus aureus disease-host genetic susceptibility and bacterial population structure." Thesis, University of Oxford, 2002. https://ora.ox.ac.uk/objects/uuid:85a3a6b4-b0cc-48ed-b584-5037ea884250.
Full textMenard, Katrina Louise. "Population genetic structure of Conophthorus ponderosae Hopkins (Coleoptera: Scolytidae) inferred from mitochondrial DNA haplotypes." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4210.
Full textTeichert, Sonja. "Habitat use and population spatial structure of the forked fungus beetle, Bolitotherus cornutus Panzer." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ45379.pdf.
Full textLaurence, Sophie. "GENETIC VARIATION AND POPULATION GENETIC STRUCTURE OF MUSKRAT, ONDATRA ZIBETHICUS, AT DIFFERENT SPATIAL SCALES." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2171.
Full textGoldberg, Caren. "Habitat, spatial population structure, and methods for monitoring barking frogs (Eleutherodactylus augusti) in southern Arizona." Thesis, The University of Arizona, 2002. http://hdl.handle.net/10150/278788.
Full textCilli, Elisabetta <1978>. "Spatial and temporal population structure and species traceability in fishery resources of the Mediterranean Sea." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1747/1/Elisabetta_Cilli_THESIS_PhD.pdf.
Full textCilli, Elisabetta <1978>. "Spatial and temporal population structure and species traceability in fishery resources of the Mediterranean Sea." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1747/.
Full textYin, Mingbo [Verfasser], and Wilfried [Akademischer Betreuer] Gabriel. "Population structure and host-parasite interactions in the Daphnia longispina hybrid complex / Mingbo Yin. Betreuer: Wilfried Gabriel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2011. http://d-nb.info/1018615741/34.
Full textOosthuysen, Wilhelm Frederick. "Population structure, host cell interactions and pathogenesis of Staphylococcus aureus strains isolated at Tygerberg hospital, South Africa." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85580.
Full textENGLISH ABSTRACT: Numerous studies conducted internationally have identified and described several endemic methicillin-susceptible Staphylococcus aureus (MSSA) clones. However, only some of these clones are associated with methicillin resistance (CC5, CC8, CC22, CC30 and CC45). To date, studies reporting on the population structure of S. aureus isolated in South Africa represent limited demographic areas, focus on methicillin-resistant S. aureus (MRSA) only and have displayed little emphasis on virulence. This study was undertaken to elucidate the population structure of S. aureus isolated from specific clinical sources at Tygerberg hospital, and to investigate specific host-pathogen interactions of representative isolates. Consecutive non-repetitive clinical S. aureus isolates were collected over one year (September 2009/2010) with patient demographics and limited clinical information. Strains were typed by PFGE and molecular markers (spa, multi-locus sequence typing (MLST), agr, Staphylococcal Chromosome Cassette mec and Panton-Valentine leukocidin (PVL)). Representative isolates were selected and investigated for the presence of virulence genes, adherence (to immobilised fibronectin [Fn], fibrinogen [Fg], collagens IV [CnIV] and VI [CnVI]), cellular invasion and cell death induction. Statistical association were determined between all in vitro results and methicillin-resistance, clonality, patient HIV status and bacterial PVL status. Fifteen percent of the isolates (n = 367) were MRSA. Forty four present of isolates were PVL+. agr I-IV and SCCmec I-V were identified. The MSSA population was diverse: ST22 (dominant), ST1865 and ST121 were PVL+. ST45, ST1863 and ST15 were PVL-. PVL- MRSA were diverse: ST612-MRSA-IV (dominant), ST5-MRSA-I, ST239-MRSA-III, ST36-MRSA-II and ST22-MRSA-IV. The genes fnbA/B (fibronectin-binding protein A/B), clfA/B (clumping factor A/B), eap (extracellular adherence protein), nuc (nuclease), coa (coagulase) and hld (delta toxin) were detected in all representative isolates. The CC8 and CC6 isolates adhered strongly to all ligands (100-700% of control, ligand dependent), while isolates of CC45, CC22 and CC88 adhered strongly only to Fg and Fn. The CC30, CC15, and CC12 isolates adhered extremely strongly to CnIV (>300%) and CC8, CC15, and C6 to CnVI (>200%). Isolates from CC30, CC8, CC15, CC6, CC12, CC97, CC88 and CC45 were highly invasive (>100%). ST121 was non-invasive (>50%). Isolates of CC5, CC30 and CC121 were non-cytotoxic (<50%), while isolates of CC22, CC8, CC15, CC45 and CC88 were very cytotoxic (>70%). No significant difference was observed in adherence or cell death induction of MRSA vs. MSSA clones or between isolates from HIV+ vs. HIV- persons. PVL- isolates displayed higher cellular invasiveness than PVL+ isolates. The presence of ST612-MRSA-IV, ST22-MRSA-V and ST8-MRSA-V points to local SCCmec acquisition, as we found MSSA isolates with the same spa types. Numerous MSSA clones were prevalent, but do not appear to have a major common genetic background with MRSA. PVL was highly prevalent among MSSA, indicating acquisition of PVL genes independently of SCCmec. The abilities to adhere to specific immobilised ligands in vitro were diverse and grouped with the genetic background, while the vast majority of isolates were invasive and induced significant cell death. We can conclude that the population of S. aureus at Tygerberg hospital is composed of a vast number of MSSA and MRSA clones, which display varying patters of adherence to selected ligands and of which, the majority clones are invasive and cytotoxic.
AFRIKAANSE OPSOMMING: Talle internasionale studies het verskeie endemiese metisillien vatbare Staphylococcus aureus (MSSA) klone geïdentifiseer en beskryf. Slegs 'n paar van hierdie klone word geassosieer met metisillien weerstandigheid (Klonale kompleks (KK) 5, KK8, KK22, KK30 en KK45). Studies oor die bevolking struktuur van S. aureus geïsoleer in Suid-Afrika is tot dusver beperk tot demografiese gebiede, fokus slegs op metisillien-weerstande S. aureus (MRSA) en het min klem op virulensie geplaas. Hierdie studie is onderneem om die bevolking struktuur van S. aureus, geïsoleer vanaf spesifieke kliniese bronne, in die pasiëntpopulasie van Tygerberg-hospitaal te ondersoek en om ondersoek in te stel na spesifieke gasheer-patogeen interaksies van verteenwoordigende isolate. Opeenvolgende, nie-herhalende en suiwer kliniese S. aureus isolate is versamel oor ´n periode van een jaar (September 2009/2010), tesame met pasiënt demografiese- en beperkte kliniese inligting. Stamme is deur PFGE en molekulêre merkers (spa, MLST, agr, SCCmec en PVL) beskryf. Verteenwoordigende isolate is gekies en ondersoek vir die teenwoordigheid van virulensie gene, aanhegting ( aan geïmmobiliseerde fibronektien [Fn], fibrinogeen [Fg], kollageen IV [CnIV] en kollageen VI [CnVI]), sellulêre indringing en die induksie van seldood. Statistiese assosiasies is bepaal tussen alle in vitro resultate en methicillin-weerstandigheid, klonaliteit, pasiënt MIV status en bakteriese PVL status. Fyftien persent van die isolate (n = 367) was MRSA. Vier-en-veertig van die isolate was PVL+. agrI-IV en SCCmec I-V is geïdentifiseer. Die MSSA bevolking was divers: ST22 (dominant), ST1865 en ST121 PVL +. ST45, ST1863 en ST15 was PVL+. PVL- MRSA was divers: ST612-MRSA-IV (dominant), ST5-MRSA-I, ST239-MRSA-III, ST36-MRSA-II en ST22-MRSA-IV. Die gene fnbA/B (fibronektien A/B), clfA/B (klontings faktor A/B), eap (ekstrasellulêre aanhegtings protein), nuc (nukease), coa (koagulase) en hld (delta toksien) was aangetref in alle verteenwoordigende isolate. Isolate van KK8 en KK6 het sterk aan alle ligande (100-700% van kontrole, ligand-afhanklike) aangeheg, terwyl isolate van KK45, KK22 en KK88 slegs sterk aand fibronektien en fibrinogeen aangeheg het. Isolate van KK30, KK15, en KK12 het baie sterk aan CnIV (> 300%) aangeheg en KK8, KK15, en KK6 and CnVI (> 200%). Isolate van KK30, KK8, KK15, KK6, KK12, KK97, KK88 en KK45 was hoogs indringend (> 100%). ST121 was nie-indringende (> 50%). Isolate van KK5, KK30 en KK121 was nie-sitotoksiese (<50%), terwyl isolate van KK22, KK8, KK15, KK45 en KK88 baie sitotoksies was (> 70%). Geen betekenisvolle verskil is waargeneem in die aanhegting of seldood induksie van MRSA teenoor MSSA klone of tussen isolate van MIV+ teenoor MIV- persone nie. PVL- isolate het hoër sellulêre indringing as PVL+ isolate vertoon. Die teenwoordigheid van ST612-MRSA-IV, ST22-MRSA-V en ST8-MRSA-V verwys na die plaaslike verwerwing van SCCmec, aangesien ons MSSA isolate beskryf het met dieselfde spa-tipes. Talle MSSA klone was algemeen, maar het nie 'n beduidende genetiese agtergrond met MRSA vertoon nie. PVL was baie algemeen onder MSSA isolate en die PVL gene is dalk onafhanklik van SCCmec verkry. Die vermoë om aan spesifieke geïmmobiliseer ligande in vitro aan te heg was divers en groepeer met die genetiese agtergrond, terwyl die meerderheid van die isolate indringend was en kon betekenisvolle sel dood veroorsaak. Ons kan aflei dat die bevolking van S. aureus by die Tygerberg hospitaal saamgestel is uit 'n groot aantal van MSSA en MRSA klone, wat verskillende patrone van aanhegting aan geselekteerde ligande vertoon en waarvan die meeste klone indringende en sitotoksies is.
DFG/NRF International Research and Training Group (IRTG) 1522 “HIV and associated infectious diseases in Southern Africa”
National Research Foundation
Medical Research Council, Medi-Clinic
Harry Crossley Fund (Stellenbosch University)
Stellenbosch University
De, Wit Erika. "Analysis of host determining factors in susceptibility to tuberculosis in the South African coloured population." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/4584.
Full textDissertation presented for the degree of Doctor of Philosophy in Medical Biochemistry at Stellenbosch University.
ENGLISH ABSTRACT: The infectious disease tuberculosis (TB) still represents a global threat due to its devastating effect on health and the subsequent high mortality rate. Previous studies have indicated that host genetic factors are implicated in host susceptibility to TB. Since TB is a complex disease, it can be assumed that susceptibility to M. tuberculosis has multiple genetic causative factors (as well as environmental causes). The current study focussed on a number of South African Coloured (SAC) individuals, some of whom were TB cases and others controls. Population substructure was tested in the admixed SAC population as it can be a strong confounding factor for association studies. Our results using the programme STRUCTURE indicated no population substructure in the SAC population. We further investigated the population structure of the SAC group using Affymetrix 500k SNP chip data which showed that the SAC population group has 4 major ancestral components: the Khoesan, European, African and Asian (Indian). A number of candidate polymorphisms in eight genes, previously indicated to play an important role in TB susceptibility, were tested in case-control associations studies. We found statistically significant associations between IFNGR1, IL-8, IL-1Ra and NRAMP1 polymorphisms and TB susceptibility in the SAC population. It has become increasingly evident that gene-gene interactions play a far more important part in an individual’s susceptibility to a complex disease than single polymorphisms would on their own. The importance of epistasis was clearly identifiable in this study with only four associations found between the individual variants and TB susceptibility, but eight instances of statistically significant gene-gene interactions. A combined data set consisting of 106 variants constructed from our database and also used for gene-gene interaction analysis yielded numerous statistically significant interactions. The interaction between the genotype of the human host and the bacterial strain genotype was also investigated and yielded interesting results. Owing to various polymorphisms in several cytokine genes, the protein levels of the main modulators of the immune system, cytokines and chemokines, are changed in several diseases such as infectious diseases and may affect susceptibility or resistance to TB. The functional polymorphisms or haplotype patterns in some of these cytokine genes might be vital for protective immune responses and may serve as biomarkers of protection or susceptibility to TB. The present study investigated 18 cytokines including pro-inflammatory, anti-inflammatory and chemokine factors in healthy (mantoux positive or negative) children using the Linco-plex immunoassay, and investigated potential interactions. The basic research will one day contribute to personalised genetics which may benefit infectious diseases such as TB. If individuals can be identified as potentially more vulnerable, they may require different vaccination strategies, a higher index of suspicion if exposed to TB, and prophylactic treatment.
AFRIKAANSE OPSOMMING: Die infektiewe siekte tuberkulose (TB) is steeds ‘n gevaar wat die hele wêreld bedreig weens die groot impak op gesondheid en die gevolglike hoë mortaliteit. Vorige studies het bevind dat die gasheer se genetiese faktore wel betrokke mag wees by die gasheer se vatbaarheid vir TB. Aangesien TB ‘n komplekse siekte is, kan dit aanvaar word dat vatbaarheid tot M. tuberculosis veelvuldige genetiese oorsaaklike faktore (sowel as omgewingsoorsake) het. Hierdie studie het gefokus op ‘n aantal Suid-Afrikaanse Kleurling (SAC) individue, waarvan sommige TB pasiënte en ander kontroles was. Die gemengde SAC populasie is getoets vir populasie-stratifikasie, aangesien stratifikasie ‘n sterk verwarrende invloed op pasiënt-kontrole studies kan hê. Ons resultate is verkry met behulp van die program STRUCTURE en het aangedui dat daar geen populasie sub-struktuur tussen die pasiënte en kontroles was nie. Ons het ook die populasiesamestelling van die SAC groep ondersoek met data verkrygbaar van die Affymetrix 500k enkel nukleotied polimorfisme mikroskyfie. Hierdie data het getoon dat die SAC populasie uit 4 hoof voorouerlike komponente bestaan naamlik die Khoesan, Europeërs, Afrikane en Asiate (Indiërs). ‘n Aantal kandidaat polimorfismes in agt gene, wat volgens vorige studies ‘n belangrike rol in TB vatbaarheid te speel, was in hierdie pasiënt-kontrole assosiasie studie bestudeer. Ons het statistiese beduidende verwantskappe tussen IFNGR1, IL-8, IL-1Ra en NRAMP1 polimorfismes en TB vatbaarheid in die SAC populasie gevind. Dit het al hoe meer duidelik geword dat geen-geen interaksies ‘n baie belangriker rol in ‘n individu se vatbaarheid vir ‘n komplekse siekte speel as enkel polimorfismes op hul eie. Die belang van epistase kon duidelik in hierdie studie geïdentifiseer word met slegs vier assosiasies wat tussen die individuele variante en TB vatbaarheid gevind is, in vergelyking met agt statisties beduidende geen-geen interaksies. ‘n Gekombineerde datastel wat uit ons databasis saamgestel is en wat 106 variante bevat is ook in ‘n aparte geen-geen interaksie analise gebruik, wat verskeie statisties beduidende interaksies getoon het. Die interaksie tussen die menslike gasheer genotipe en die bakteriese stam genotipe is ook in hierdie studie ondersoek en het interessante resultate opgelewer. Veranderde proteïen uitdrukking van die hoofmoduleerders van die immuunsisteem, sitokine en chemokine, kom voor in verskeie siektes soos infektiewe siektes weens verskillende polimorfismes in verskeie sitokien-gene. Sulke polimorfismes kan ook vatbaarheid vir of weerstandigheid teen TB beïnvloed. Die funksionele polimorfismes of haplotipe patrone in sommige van hierdie sitokien-gene mag noodsaaklik wees vir beskermende immuunresponse en mag ook as biomerkers vir beskerming teen of vatbaarheid vir TB dien. Hierdie studie het 18 sitokiene (insluitend pro-inflammatoriese-, anti-inflammatoriese- en chemokiene faktore), sowel as potensiële interaksies in gesonde (mantoux positiewe of negatiewe) kinders, ondersoek met behulp van die Linco-plex immuno-analise. Hierdie basiese navorsing sal eendag in die toekoms bydrae tot persoonlike genetiese analises wat tot voordeel kan wees vir infektiewe siektes soos TB. Indien individue as potensieël meer vatbaar vir TB geïdentifiseer kan word, kan sulke persone ander vaksineringstrategieë sowel as voorkomende behandeling vereis.
Piri, Rebecca D. "Spatial Genetic Structure and Local Adaptation within and among Foxtail Pine (Pinus balfouriana subsp. balfouriana) Populations Located in the Klamath Mountains, California." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6018.
Full textHailu, Solomon Ghebremeskel. "THE EFFECT OF HABITAT FRAGMENTATION ON THE SPATIAL POPULATION GENETIC STRUCTURE OF SOUTHERN PINE BEETLE (DENDROCTONUS FRONTALIS)." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/624.
Full textForien, Raphael. "The spatial structure of genetic diversity under natural selection and in heterogeneous environments." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX082/document.
Full textThis thesis deals with the spatial structure of genetic diversity. We first study a measure-valued process describing the evolution of the genetic composition of a population subject to natural selection. We show that this process satisfies a central limit theorem and that its fluctuations are given by the solution to a stochastic partial differential equation. We then use this result to obtain an estimate of the drift load in spatially structured populations.Next we investigate the genetic composition of a populations whose individuals move more freely in one part of space than in the other (a situation called dispersal heterogeneity). We show in this case the convergence of allele frequencies via the convergence of ancestral lineages to a system of skew Brownian motions.We then detail the effect of a barrier to gene flow dividing the habitat of a population. We show that ancestral lineages follow partially reflected Brownian motions, of whom we give several constructions.To apply these results, we adapt a method for demographic inference to the setting of dispersal heterogeneity. This method makes use of long blocks of genome along which pairs of individuals share a common ancestry, and allows to estimate several demographic parameters when they vary accross space. To conclude, we demonstrate the accuracy of our method on simulated datasets
Boothe, Rena Almena. "Influence of host plant and host population structure on physiological and behavioural characteristics of Chilocorus nigritus and the efficacy of control of the scale insect, Aspidiotus nerii (Bouche)." Thesis, University of Kent, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523517.
Full textZehetbauer, Josef [Verfasser], and Christoph [Akademischer Betreuer] Walker. "Stability of equilibria for a nonlinear population model with age- and spatial-structure / Josef Zehetbauer ; Betreuer: Christoph Walker." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1204459304/34.
Full textLee, David Jung-Hwi. "Optimal Regional Allocation of Population and Employment: Application of a Spatial Interaction Commuting Model." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276787325.
Full textMcConway, Alex. "The effects of trace metals on juvenile cockles (Austrovenus stutchburyi)." Thesis, University of Canterbury. Biological Sciences, 2008. http://hdl.handle.net/10092/1696.
Full textStasek, David Jon. "BUTTERFLY MOVEMENTS AMONG ISOLATED PRAIRIE PATCHES: HABITAT EDGE, ISOLATION, AND FOREST-MATRIX EFFECTS." Oxford, Ohio : Miami University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1150217598.
Full textWoo, Myungje. "Impacts of urban containment policies on urban growth and structure." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195263668.
Full textBrewer, Andrew M. "Interactions between demographic rates, population density and the environment : the spatial structure of the range of the holly leaf-miner." Thesis, University of Sheffield, 2001. http://etheses.whiterose.ac.uk/14830/.
Full textStraulino, Daniel. "Selection in a spatially structured population." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:3a20f7a3-27cd-4cbb-9e88-7ebb21ce4e0d.
Full textTambarussi, Evandro Vagner. "Contemporary gene flow, mating system, and spatial genetic structure in a Jequitibá-rosa (Cariniana legalis Mart. Kuntze) fragmented population by microsatellite markers." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-24032014-101908/.
Full textCariniana legalis Mart. O. Kuntze (Lecidiaceae) é a maior árvore da Mata Atlântica. Para contribuir com a conservação in e ex situ nós investigamos a diversidade genética, endogamia, estrutura genética espacial intrapopulacional (EGE), sistema de reprodução e fluxo contemporâneo de pólen em três populações fragmentadas da espécie. Encontrámos 65 árvores adultas na população Ibicatu, 22 em MGI, e quatro em MGII. As sementes foram colhidas e amostradas hierarquicamente entre e dentro de frutos diretamente da copa de 15 árvores matrizes em Ibicatu (n = 40), cinco em MGI (n = 50), e duas em MGII (n = 100). Treze locos microssatélites foram desenvolvidos e validados em 51 indivíduos de C. legalis. Onze deles foram polimórficos, revelando um máximo de dois a 15 alelos por loco. Usando os genótipos das progênies e matrizes, foi investigada a herança mendeliana, ligação genética e desequilíbrio genotípico de sete locos isolados de C. legalis e dois heterólogos. Não foram detectados desvios notáveis da segregação mendeliana, de ligação, ou desequilíbrio genotípico. A riqueza alélica média de adultos de Ibicatu foi 11,65 e 14,29 para MGI-II e para as sementes foi de 14,18 em Ibicatu e 10,85 na MGI-II, a heterozigosidade média observada para adultos em Ibicatu foi 0,811 e 0,838 para MGI-II, para as sementes foi de 0,793 em Ibicatu e 0,786 em MGI-II, a heterozigosidade média esperada para adultos de Ibicatu foi 0,860 e 0,900 para MGI-II, para as sementes foi de 0,856 em Ibicatu e 0,853 em MGI-II. O índice médio de fixação foi significativamente maior do que zero para adultos e sementes de ambas as populações. A taxa de cruzamento Multilocus (? ) nas três populações foi significativamente menor do que a unidade (1,0), especialmente para MGII ( = 0,830). A taxa de acasalamento entre parentes foi significativa apenas para Ibicatu ( . A correleção de paternidade foi substancialmente maior dentro do que entre os frutos. O coeficiente médio de coancestria (?) foi maior e variação de tamanho efetivo (Ne ) foi menor do que o esperado para progênies de meio-irmãos em todas as populações. O número estimado de árvores matrizes necessárias para a coleta de sementes para se obter um tamanho efetivo de 150 foi de 54-58 árvores. A taxa de imigração de pólen foi baixa, especialmente para os fragmentos menores (máximo de 0,4% para MGI), indicando isolamento genético significativo. O raio efetivo de polinização foi baixo em MGI (68 m) e MGII (191 m). Para MGII também encontramos níveis mais elevados de autofecundação (18%) do que para Ibicatu (6%) e MGI (6,4%). O isolamento genético substancial desses estandes sugerem que podemos esperar um aumento na EGE e que estratégias para aumentar o fluxo gênico e tamanho efetivo da população, como o transplante de indivíduos nas populações, são desejáveis para o longo prazo. Em conclusão, este estudo gerou informações valiosas para a gestão de populações fragmentadas de C. legalis, contribuindo para programas de melhoramento e fornecendo orientações para a coleta de sementes destinadas a programas de conservação e reflorestamento.
Adams, Thomas P. "Reconstructing Scotland's pine forests." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4730.
Full textCorrales, Duque Carolina. "Population Genetic Structure of Black Grouse (Tetrao tetrix) : From a Large to a Fine Scale Perspective." Doctoral thesis, Uppsala universitet, Institutionen för ekologi och genetik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-150117.
Full textPuncher, Gregory Neils <1980>. "Assessment of the population structure and temporal changes in spatial dynamics and genetic characteristics of the Atlantic bluefin tuna under a fishery independent framework." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7227/4/Puncher_Gregory_Neils_tesi.pdf.
Full textPuncher, Gregory Neils <1980>. "Assessment of the population structure and temporal changes in spatial dynamics and genetic characteristics of the Atlantic bluefin tuna under a fishery independent framework." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7227/.
Full textHannunen, Salla. "Trivial movements and redistribution of polyphagous insect herbivores in heterogeneous vegetation /." Uppsala : Swedish Univ. of Agricultural Sciences, Dept. of Entomology, 2003. http://epsilon.slu.se/a376.pdf.
Full textBanda, Jo Ann. "Temporal and Spatial Genetic Consistency of Walleye (Sander vitreus) Spawning Groups." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321498533.
Full textAndersson, Bea Angelica. "Analysis of Selection and Genetic Drift in a Dioecious Plant : Spatial Genetic Structure and Selection in Phenotypic Traits in a Young Island Population of Silene dioica." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-96275.
Full textSjolund, M. Jennifer. "Interactions between natural and anthropogenic impacts on the genetic diversity and population genetic structure of European beech forests." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/21657.
Full textClostio, Rachel Wallace. "Use of environmental variables to infer gene flow and population structure in the gopher tortoise (Gopherus polyphemus) and predict the seroprevalence of an emerging infectious disease." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1230.
Full textFisco, Dana. "Reef Fish Spatial Distribution and Benthic Habitat Associations on the Southeast Florida Reef Tract." NSUWorks, 2016. http://nsuworks.nova.edu/occ_stuetd/408.
Full textChumacero, de Schawe Claudia [Verfasser], Teja [Akademischer Betreuer] Tscharntke, Michael [Akademischer Betreuer] Kessler, Isabell [Akademischer Betreuer] Hensen, and Dirk [Akademischer Betreuer] Gansert. "Pollination ecology and spatial genetic population structure of wild and cultivated species of cacao (Theobroma) in Bolivia / Claudia Chumacero de Schawe. Gutachter: Michael Kessler ; Isabell Hensen ; Dirk Gansert. Betreuer: Teja Tscharntke." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1048734498/34.
Full textLeger, Elsa. "Structure de la communauté d'hôtes et évolution de la spécialisation chez la tique Ixodes ricinus." Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON13512.
Full textThe degree of host specialization in parasites can greatly modify the nature of interspecific interactions. When parasites are also vectors, their ability to adapt to new hosts and their response to changes in the host community will have important consequences for both their population dynamics and evolution, but may also cascade down to the microparasites they transmit. A first step to better apprehend the importance of this phenomenon for the evolution and ecology of vector-borne disease systems is to study patterns of host-associated genetic divergence across diverse vector populations. We used this approach in the host-vector-pathogen system involving the European tick Ixodes ricinus, its various vertebrate hosts and the bacteria responsible for Lyme disease Borrelia burgdorferi sl. We predicted that longer established interactions would show stronger patterns of host-associated divergence than more recently established ones. We tested this prediction by combining field samples from a European-wide transect (including both historical and newly colonized zones) and molecular analyses based on 14 microsatellite markers (9 newly developed). As a major obstacle for tackling the question of host associations in the I. ricinus system is determining local host use, we also experimentally tested for biases in molecular host detection. Our results reveal a complex pattern of tick adaptation across the European landscape; host specialization does evolve, but not in a predictable way in relation to the evolutionary age of the interaction. More generally, the results of this thesis highlight that vector ecology (and not just host-pathogen interactions) require careful consideration, if we are to improve our understanding of these systems