58 resultados para azimuthal variation


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Pertussis or whooping cough is a highly contagious vaccine-preventable disease of the human respiratory tract caused by the Bordetella pertussis bacteria. In Finland, pertussis vaccinations were started in 1952 leading to a dramatic decrease in the morbidity and mortality. In the late 1990s, the incidence of pertussis increased despite the high vaccination coverage. Strain variation has been connected to the re-emergence of pertussis in countries with long history of pertussis vaccination. In 2005, the pertussis vaccine and the vaccination schedule were changed in Finland. The molecular epidemiology and the strain variation of the B. pertussis isolates were examined in Finland and in countries with similar (France) and different (Sweden) vaccination history. Continuous evolution of the B. pertussis population in Finland was observed since the 1950s, and the recently circulating isolates were antigenically different from the vaccine strains. Comparison of the circulating isolates from Finland, France and Sweden did not refer to significant differences. Certain type of strains noticed in France already in 1994 mainly caused the recent epidemics in Sweden (1999) and in Finland (2003-4). On several occasions, a new type of strains first appeared in Sweden and some years later in Finland. The B. pertussis isolates from the infants were shown to be similar to those from the other age groups. It is suggested that the strains originate from the same reservoir among adolescents and adults. The strain variation does not seem to have a major effect on the morbidity among recently vaccinated individuals, but it might play a role among those who are in the waning phase of immunity. The incidence of pertussis in Finland has remained low since the change of the vaccination programme. This might be related to the epidemic nature of pertussis and the near future will show the real effectiveness of the new vaccination programme. At present, many infants are infected because they are too young to be immunised with the current schedule. New strategies or vaccines are needed to protect those who are the most vulnerable.

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In many industrial applications, accurate and fast surface reconstruction is essential for quality control. Variation in surface finishing parameters, such as surface roughness, can reflect defects in a manufacturing process, non-optimal product operational efficiency, and reduced life expectancy of the product. This thesis considers reconstruction and analysis of high-frequency variation, that is roughness, on planar surfaces. Standard roughness measures in industry are calculated from surface topography. A fast and non-contact method to obtain surface topography is to apply photometric stereo in the estimation of surface gradients and to reconstruct the surface by integrating the gradient fields. Alternatively, visual methods, such as statistical measures, fractal dimension and distance transforms, can be used to characterize surface roughness directly from gray-scale images. In this thesis, the accuracy of distance transforms, statistical measures, and fractal dimension are evaluated in the estimation of surface roughness from gray-scale images and topographies. The results are contrasted to standard industry roughness measures. In distance transforms, the key idea is that distance values calculated along a highly varying surface are greater than distances calculated along a smoother surface. Statistical measures and fractal dimension are common surface roughness measures. In the experiments, skewness and variance of brightness distribution, fractal dimension, and distance transforms exhibited strong linear correlations to standard industry roughness measures. One of the key strengths of photometric stereo method is the acquisition of higher frequency variation of surfaces. In this thesis, the reconstruction of planar high-frequency varying surfaces is studied in the presence of imaging noise and blur. Two Wiener filterbased methods are proposed of which one is optimal in the sense of surface power spectral density given the spectral properties of the imaging noise and blur. Experiments show that the proposed methods preserve the inherent high-frequency variation in the reconstructed surfaces, whereas traditional reconstruction methods typically handle incorrect measurements by smoothing, which dampens the high-frequency variation.

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Soitinnus: piano. Sininen helmi -baletin kolmannen näytöksen lisäaineistoa. Melartinin käsikirjoitusluettelon tunnus Mel 11:67 (ks. http://lib.siba.fi/fi/kokoelmat/kasikirjoitusarkisto/melartin_erkki/).

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This dissertation discusses Holocene palaeoenvironmental and palaeomagnetic secular variation (PSV) records reconstructed from sediments preserved in Lake Lehmilampi (63º37´N, 29º06´E) and Lake Kortejärvi (63º37´N, 28º56´E) in eastern Finland. Several piston and freeze cores were obtained from both lakes for varve and magnetic analyses. Sediment samples were impregnated in low-viscosity epoxy and physical parameters of varves, including varve thickness and relative grey-scale values, were recorded using x-ray densitometry combined with semiautomatic digital image analysis. On average, varve records of Lehmilampi and Kortejärvi cover 5122 and 3902 years, respectively. Past solar activity, as estimated by residual 14C data, compares favourably with varve thicknesses from Lehmilampi during the last 2000 years. This indicates the potential of clastic-organic varves to record sensitively climatic variations. Bulk magnetic parameters, including magnetic susceptibility together with natural, anhysteretic and isothermal remanent magnetizations, were measured to describe mineral magnetic properties and geomagnetic palaeosecular variation recorded in the sediments. Main stages in the development of the investigated lakes are reflected in the variations in the mineral magnetic records, sediment lithology and composition. Similar variations in magnetic parameters and sediment organic matter suggest contribution of bacterial magnetite in the magnetic assemblages of Lehmilampi. Inclination and relative declination records yielded largely consistent results, attesting to the great potential of these sediments to preserve directional palaeosecular variation in high resolution. The PSV data from Lehmilampi and Kortejärvi were stacked into North Karelian PSV stack, which may be used for dating homogenous lake sediments in the same regional context. Reconstructed millennial variations in relative palaeointensity results are approximately in agreement with those seen in the absolute palaeointensity data from Europe. Centennial variations in the relative palaeointensity, however, are influenced by environmental changes. Caution is recommended when using varved lake sediments in reconstructing relative palaeointensity.

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A common feature of natural populations is that individuals differ in morphology, physiologyand behavior (i.e .phenotype). A thorough understanding of the molecular mechanisms and evolutionary forces behind this phenotypic variation is a prerequisite for understanding evolution.This thesis examines the molecular mechanism and the roles of the different evolutionary forces in plumage colour variation in pied flycatchers (Ficedulahypoleuca). Malepied flycatchers exhibit marked variation in both pigmentary and structural plumage colourand the trait has repeatedly been suggested to be of adaptive significance. An examination of plumage colour variation on reproductive output trevealed that structural colouration, and more specifically the degree of ultraviolet (UV) reflectance had an effect on number of young sired. Paternity analyses of breeding males revealed that males that had been cuckolded by their social mate tended to be less UV reflectant than males that had not been cuckolded.Neither pigment-based norstructural colouration was found to affect the probability of siring young in other nests. Phenotypic differentiation was found to be markedly greater than differentiation at neutralgenetic markers across the pied flycatcher breeding range. Furthermore patterns of differentiationin phenotypes and selectively neutral genes were not uniform. Outlier tests searching for genomic footprints of selection revealed elevated levels of genetic divergence in a gene associated with feather development (and thus potentially structural colouration) and ultraviolet vision. Th eobserved differentiation in allelic frequencies was particularly pronounced in the Spanish piedflycatcher populations. Examining gene expression during feather development indicated that the TYRP1 gene (known to be involved in the production of black pigment) may be relevant in generating phenotypic variation in pied flycatcher plumage. Also, energy homeostasis related genesfeatured prominently among the genes found to be expressed in one extreme phenotype but not the other. This is of particular interest in light of what is known about the pleiotropy ofthe melanocortin system which underlies brown-black pigment production. The melanocortinsystem is also associated with energy homeostasis (among a number of other physiological functions) and thus the results could be pointing to the signalling function of brown-blackplumage. Plumage colour variation in pied flycatchers, both structural and pigmentary, can thus beconcluded to be exhibiting signals of non-neutral evolution. Structural colouration was found to play a role in sexual selection and putative signals of selection were further detected in acandidate gene for this trait. Evidence for non-neutral evolution of pigmentary colouration was also detected. These findings, together with the fact that preliminary evidence for an energy balance associated signalling function for plumage was found, present good starting points for further investigations into the meaning and mechanisms of plumage colour variation in piedflycatchers.

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I sin avhandling studerar Viveca Rabb grammatiskt genus i Kvevlaxdialekten i Österbotten. Det traditionella tregenussystemet med maskulinum (t.ex. hande biilin 'den där bilen'), femininum (t.ex. honde såjen 'den där sågen') och neutrum (hede epłe 'det där äpplet') befinner sig i förändring. Rabb fokuserar i sin avhandling på den bestämda slutartikeln och på fem pronomen, nämligen honde/hande 'den där', miin/menn 'min', eron/eran 'er' in tołonde/in tołinde 'en sån där' samt naon/nain 'någon'. Förändringarna i genussystemet diskuteras genom en analys av rapporterat språkbeteende i byarna Kvevlax, Koskö, Vassor och Västerhankmo i nuvarande Korsholm, och med hjälp av grammatisk teori och språksociologi. Informanterna hör till tre olika åldersgrupper: födda ca 1920, 1950 och 1980. Metoden är främst kvantitativ och inbegriper statistisk testning. Undersökningen visar att äldre, lägre utbildade och stationära informanter använde feminint genus mera än yngre, högre utbildade informanter som pendlar till sitt arbete. Informanternas hemby hade betydelse vid bevarandet av feminint (men inte maskulint) genus, medan deras kön inte hade någon påvisbar betydelse. Analysen visar även hur substantivböjningen har betydelse vid val av pronomenvariant (maskulin, feminin eller neutral), men att användningen av den bestämda slutartikeln som ledtråd till genus ändå tycks vara på tillbakagång, och då främst vid orden med den bestämda slutartikeln -en (t.ex. handen). Detta gynnar maskulint genus (hande) på bekostnad av feminint genus (honde). Konkreta substantiv bevarar vidare feminint genus bättre än abstrakta. Suffixet -ingg verkar kopplas samman med feminint genus, medan suffixen -heit och -els kopplas till maskulint genus. Det semantiska fältet träd har å sin sida betydelse främst i de byar (Vassor och Västerhankmo) där ledtrådar från substantivböjningen saknas. Resultaten ger sålunda en bild av ett samspel mellan överlappande ledtrådar i ett system där kongruensen på pronomenen minskar och användningen av feminint genus avtar.

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"Helmiä sioille", pärlor för svin, säger man på finska om någonting bra och fint som tas emot av en mottagare som inte vill eller har ingen förmåga att förstå, uppskatta eller utnyttja hela den potential som finns hos det mottagna föremålet, är ointresserad av den eller gillar den inte. För sådana relativt stabila flerordiga uttryck, som är lagrade i språkbrukarnas minnen och som demonstrerar olika slags oregelbundna drag i sin struktur använder man inom lingvistiken bl.a. termerna "idiom" eller "fraseologiska enheter". Som en oregelbundenhet kan man t.ex. beskriva det faktum att betydelsen hos uttrycket inte är densamma som man skulle komma till ifall man betraktade det som en vanlig regelbunden fras. En annan oregelbundenhet, som idiomforskare har observerat, ligger i den begränsade förmågan att varieras i form och betydelse, som många idiom har jämfört med regelbundna fraser. Därför talas det ofta om "grundform" och "grundbetydelse" hos idiom och variationen avses som avvikelse från dessa. Men när man tittar på ett stort antal förekomstexempel av idiom i språkbruk, märker man att många av dem tillåter variation, t.o.m. i sådan utsträckning att gränserna mellan en variant och en "grundform" suddas ut, och istället för ett idiom råkar vi plötsligt på en "familj" av flera besläktade uttryck. Allt detta väcker frågan om hur dessa uttryck egentligen ska vara representerade i språket. I avhandlingen utförs en kritisk granskning av olika tidigare tillvägagångssätt att beskriva fraseologiska enheter i syfte att klargöra vilka svårigheter deras struktur och variation erbjuder för den lingvistiska teorin. Samtidigt presenteras ett alternativt sätt att beskriva dessa uttryck. En systematisk och formell modell som utvecklas i denna avhandling integrerar en beskrivning av idiom på många olika språkliga nivåer och skildrar deras variation i form av ett nätverk och som ett resultat av samspel mellan idiomets struktur och kontexter där det förekommer, samt av interaktion med andra fasta uttryck. Modellen bygger på en fördjupande, språkbrukbaserad analys av det finska idiomet "X HEITTÄÄ HELMIÄ SIOILLE" (X kastar pärlor för svin).