9 resultados para three-hybrid system
em Helda - Digital Repository of University of Helsinki
Resumo:
This dissertation is a synchronic description of adnominal person in the highly synthetic morphological system of Erzya as attested in extensive Erzya-language written-text corpora consisting of nearly 140 publications with over 4.5 million words and over 285,000 unique lexical items. Insight for this description have been obtained from several source grammars in German, Russian, Erzya, Finnish, Estonian and Hungarian, as well as bounteous discussions in the understanding of the language with native speakers and grammarians 1993 2010. Introductory information includes the discussion of the status of Erzya as a lan- guage, the enumeration of phonemes generally used in the transliteration of texts and an in-depth description of adnominal morphology. The reader is then made aware of typological and Erzya-specifc work in the study of adnominal-type person. Methods of description draw upon the prerequisite information required in the development of a two-level morphological analyzer, as can be obtained in the typological description of allomorphic variation in the target language. Indication of original author or dialect background is considered important in the attestation of linguistic phenomena, such that variation might be plotted for a synchronic description of the language. The phonological description includes the establishment of a 6-vowel, 29-consonant phoneme system for use in the transliteration of annotated texts, i.e. two phonemes more than are generally recognized, and numerous rules governing allophonic variation in the language. Erzya adnominal morphology is demonstrated to have a three-way split in stem types and a three-layer system of non-derivative affixation. The adnominal-affixation layers are broken into (a) declension (the categories of case, number and deictic marking); (b) nominal conjugation (non-verb grammatical and oblique-case items can be conjugated), and (c) clitic marking. Each layer is given statistical detail with regard to concatenability. Finally, individual subsections are dedicated to the matters of: possessive declension compatibility in the distinction of sublexica; genitive and dative-case paradigmatic defectivity in the possessive declension, where it is demonstrated to be parametrically diverse, and secondary declension, a proposed typology modifiers without nouns , as compatible with adnominal person.
Resumo:
Gender in eastern Nyland – from dialect levelling to identity marking The study of dialect leveling in eastern Nyland focuses on variation and change in the Swedish dialects of Nyland (Fi. Uusimaa) on the south coast of Finland. During the last century the grammatical gender system of the dialects in the area has been reduced from a three-gender system to a two-gender system (cf. Corbett 1991). The present study is based on five linguistic variables in the gender system: the anaphoric pronouns (han, hon, den) when used for inanimates; the neuter pronouns he(t) and de(t) – when used anaphorically or as expletives; and three different types of morphological postposed definite articles. For all these variables, both dialect variants and standard variants are used in the dialects. Within the study of processes of variation and change, the work focuses on the mechanisms of leveling, simplification and reallocation; cf. Trudgill (1986) and Hinskens, Auer Kerswill (2005). With regard to the reductions of the gender system, the possibility that some of these variables might have turned into becoming dialect markers (Labov 1972) in the modern varieties of eastern Nyland is given special attention. The primary data consist of tape recordings with 25 informants done in the 1960s and 1970s. The informants were born in 1881–1913. In addition, recent changes were investigated in detail in tape recordings from 2005–2008 with 15 informants, who were born in the period 1927–1947 or 1976–1988. The study combines quantitative and qualitative methods in the systematic analysis of the data. Theoretically and methodologically the study relies on methods and results from variation studies and socio-dialectology, as well as on methods and results from traditional dialectology; cf. Ahlbäck (1946) and the dictionary of Swedish dialects, Ordbok över Finlands svenska folkmål, (1976–). The results show that there are different strategies among the informants in their use of the features studied. In the modern varieties of the dialects, most of the informants use only two genders, uter and neuter. Of the variables, the masculine pronoun for inanimates, the traditional neuter pronoun he(t) and some variants of the traditional definite articles have received a new function as dialect markers in my data. These changes first affect the gender distinctions, and the function of marking gender is lost; gradually the features then get new functions as dialect markers through processes of dialect leveling and reallocation. These processes are connected to changes taking place in the communities in eastern Nyland because of urbanization. When the dialect speakers experience that the traditional values of both the dialects and the culture are threatened, they begin to mark their dialectal identity by using dialect markers in their speech.
Resumo:
In this dissertation we study the interaction between Saturn's moon Titan and the magnetospheric plasma and magnetic field. The method of research is a three-dimensional computer simulation model, that is used to simulate this interaction. The simulation model used is a hybrid model. Hybrid models enable individual tracking or tracing of ions and also take into account the particle motion in the propagation of the electromagnetic fields. The hybrid model has been developed at the Finnish Meteorological Institute. This thesis gives a general description of the effects that the solar wind has on Earth and other planets of our solar system. Planetary satellites can also have similar interactions with the solar wind but also with the plasma flows of planetary magnetospheres. Titan is clearly the largest among the satellites of Saturn and also the only known satellite with a dense atmosphere. It is the atmosphere that makes Titan's plasma interaction with the magnetosphere of Saturn so unique. Nevertheless, comparisons with the plasma interactions of other solar system bodies are valuable. Detecting charged plasma particles requires in situ measurements obtainable through scientific spacecraft. The Cassini mission has been one of the most remarkable international efforts in space science. Since 2004 the measurements and images obtained from instruments onboard the Cassini spacecraft have increased the scientific knowledge of Saturn as well as its satellites and magnetosphere in a way no one was probably able to predict. The current level of science on Titan is practically unthinkable without the Cassini mission. Many of the observations by Cassini instrument teams have influenced this research both the direct measurements of Titan as well as observations of its plasma environment. The theoretical principles of the hybrid modelling approach are presented in connection to the broader context of plasma simulations. The developed hybrid model is described in detail: e.g. the way the equations of the hybrid model are solved is shown explicitly. Several simulation techniques, such as the grid structure and various boundary conditions, are discussed in detail as well. The testing and monitoring of simulation runs is presented as an essential routine when running sophisticated and complex models. Several significant improvements of the model, that are in preparation, are also discussed. A main part of this dissertation are four scientific articles based on the results of the Titan model. The Titan model developed during the course of the Ph.D. research has been shown to be an important tool to understand Titan's plasma interaction. One reason for this is that the structures of the magnetic field around Titan are very much three-dimensional. The simulation results give a general picture of the magnetic fields in the vicinity of Titan. The magnetic fine structure of Titan's wake as seen in the simulations seems connected to Alfvén waves an important wave mode in space plasmas. The particle escape from Titan is also a major part of these studies. Our simulations show a bending or turning of Titan's ionotail that we have shown to be a direct result of the basic principles in plasma physics. Furthermore, the ion flux from the magnetosphere of Saturn into Titan's upper atmosphere has been studied. The modelled ion flux has asymmetries that would likely have a large impact in the heating in different parts of Titan's upper atmosphere.
Resumo:
In his grammatical treatise, the Astadhyayi, Panini includes sutras that state guiding rules for the right interpretation and application of his other directly grammatical sutras. These sutras are called paribhasas. In addition to these paribhasas, the various commentaries on Panini frequently invoke supplementary paribhasas which are not stated explicitly in his Astadhyayi. These paribhasas have been a subject of study since early times after Panini and have also occupied modern scholars on Panini s grammar. In regard to most of them, it remains unsettled even today whether they are used in the Astadhyayi, where they apply, what is their role, and whether they are necessary in arriving at the desired grammatical form. Some scholars go even further and argue that none of such paribhasas were intended by Panini. This study aims to settle this question by dealing with three such of these paribhasas individually considering all the information available in the commentaries in their regard and examining the cases in which, according to commentaries, the paribhasas apply. I select the paribhasas arthavadgrahane nanarthakasya, laksanapratipadoktayoh pratipadoktasyaiva grahanam and ekadesavikrtam ananyavat, which are all considered nyayasiddha or lokanyayasiddha; they express logical and obvious principles which are found in daily life. On this basis, Paniniyas explain why Panini did not mention them in the Astadhyayi. I discuss each paribhasa separately and all the issues it involves. I present and explain the cases where the specified paribhasas are invoked in the major commentaries, the Mahabhasya, the Kasika and the Siddhantakaumudi and the arguments found in the commentaries concerning these cases. If available, I supply other solutions to the difficulties for which these paribhasas are invoked. The study aims to make the issue of these paribhasas clearer, which will help us to reach a solution to the key question, that is, whether Panini has presupposed them in his Astadhyayi. My study shows that Panini has presupposed the paribhasa ekadesavikrtam ananyavat (or a similar principle). He also may have used the paribhasa arthavadgrahane nanarthakasya (or a similar principle) as this paribhasa does not lead to undesired results. As for the paribhasa laksanapratipadoktayoh pratipadoktasyaiva grahanam (or a similar principle), the original scope of this paribhasa was clearly extended by later Paniniyas. Moreover, their interpretation of this paribhasa conflicts with Panini s procedure. If Panini has used this paribhasa, he has used it in a very limited way.
Resumo:
The primary aim of the present study was to find an efficient and simple method of vegetative propagation for producing large numbers of hybrid aspen (Populus tremuloides L. x P. tremula Michx.) plants for forest plantations. The key objectives were to investigate the main physiological factors that affect the ability of cuttings to regenerate and to determine whether these factors could be manipulated by different growth conditions. In addition, clonal variation in traits related to propagation success was examined. According to our results, with the stem cutting method, depending on the clone, it is possible to obtain only 1−8 plants from one stock plant per year. With the root cutting method the corresponding values for two-year-old stock plants are 81−207 plants. The difference in number of cuttings between one- and two-year-old stock plants is so pronounced that it is economically feasible to grow stock plants for two years. There is no reason to use much older stock plants as a source of cuttings, as it has been observed that rooting ability diminishes as root diameter increases. Clonal variation is the most important individual factor in propagation of hybrid aspen. The fact that the efficiently sprouted clones also rooted best facilitates the selection of clones for large-scale propagation. In practice, root cuttings taken from all parts of the root system of hybrid aspen were capable of producing new shoots and roots. However, for efficient rooting it is important to use roots smaller than one centimeter in diameter. Both rooting and sprouting, as well as sprouting rate, were increased by high soil temperature; in our studies the highest temperature tested (30ºC) was the best. Light accelerated the sprouting of root cuttings, but they rooted best in dark conditions. Rooting is essential because without roots the sprouted cutting cannot survive long. For aspen the criteria for clone selection are primarily fiber qualities and growth rate, but ability to regenerate efficiently is also essential. For large-scale propagation it is very important to find clones from which many cuttings per stock plant can be obtained. In light of production costs, however, it is even more important that the regeneration ability of the produced cuttings be high.
Resumo:
The studies presented in this thesis contribute to the understanding of evolutionary ecology of three major viruses threatening cultivated sweetpotato (Ipomoea batatas Lam) in East Africa: Sweet potato feathery mottle virus (SPFMV; genus Potyvirus; Potyviridae), Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus; Closteroviridae) and Sweet potato mild mottle virus (SPMMV; genus Ipomovirus; Potyviridae). The viruses were serologically detected and the positive results confirmed by RT-PCR and sequencing. SPFMV was detected in 24 wild plant species of family Convolvulacea (genera Ipomoea, Lepistemon and Hewittia), of which 19 species were new natural hosts for SPFMV. SPMMV and SPCSV were detected in wild plants belonging to 21 and 12 species (genera Ipomoea, Lepistemon and Hewittia), respectively, all of which were previously unknown to be natural hosts of these viruses. SPFMV was the most abundant virus being detected in 17% of the plants, while SPMMV and SPCSV were detected in 9.8% and 5.4% of the assessed plants, respectively. Wild plants in Uganda were infected with the East African (EA), common (C), and the ordinary (O) strains, or co-infected with the EA and the C strain of SPFMV. The viruses and virus-like diseases were more frequent in the eastern agro-ecological zone than the western and central zones, which contrasted with known incidences of these viruses in sweetpotato crops, except for northern zone where incidences were lowest in wild plants as in sweetpotato. The NIb/CP junction in SPMMV was determined experimentally which facilitated CP-based phylogenetic and evolutionary analyses of SPMMV. Isolates of all the three viruses from wild plants were genetically similar to those found in cultivated sweetpotatoes in East Africa. There was no evidence of host-driven population genetic structures suggesting frequent transmission of these viruses between their wild and cultivated hosts. The p22 RNA silencing suppressor-encoding sequence was absent in a few SPCSV isolates, but regardless of this, SPCSV isolates incited sweet potato virus disease (SPVD) in sweetpotato plants co-infected with SPFMV, indicating that p22 is redundant for synergism between SCSV and SPFMV. Molecular evolutionary analysis revealed that isolates of strain EA of SPFMV that is largely restricted geographically in East Africa experience frequent recombination in comparison to isolates of strain C that is globally distributed. Moreover, non-homologous recombination events between strains EA and C were rare, despite frequent co-infections of these strains in wild plants, suggesting purifying selection against non-homologous recombinants between these strains or that such recombinants are mostly not infectious. Recombination was detected also in the 5 - and 3 -proximal regions of the SPMMV genome providing the first evidence of recombination in genus Ipomovirus, but no recombination events were detected in the characterized genomic regions of SPCSV. Strong purifying selection was implicated on evolution of majority of amino acids of the proteins encoded by the analyzed genomic regions of SPFMV, SPMMV and SPCSV. However, positive selection was predicted on 17 amino acids distributed over the whole the coat protein (CP) in the globally distributed strain C, as compared to only 4 amino acids in the multifunctional CP N-terminus (CP-NT) of strain EA largely restricted geographically to East Africa. A few amino acid sites in the N-terminus of SPMMV P1, the p7 protein and RNA silencing suppressor proteins p22 and RNase3 of SPCSV were also submitted to positive selection. Positively selected amino acids may constitute ligand-binding domains that determine interactions with plant host and/or insect vector factors. The P1 proteinase of SPMMV (genus Ipomovirus) seems to respond to needs of adaptation, which was not observed with the helper component proteinase (HC-Pro) of SPMMV, although the HC-Pro is responsible for many important molecular interactions in genus Potyvirus. Because the centre of origin of cultivated sweetpotato is in the Americas from where the crop was dispersed to other continents in recent history (except for the Australasia and South Pacific region), it would be expected that identical viruses and their strains occur worldwide, presuming virus dispersal with the host. Apparently, this seems not to be the case with SPMMV, the strain EA of SPFMV and the strain EA of SPCSV that are largely geographically confined in East Africa where they are predominant and occur both in natural and agro-ecosystems. The geographical distribution of plant viruses is constrained more by virus-vector relations than by virus-host interactions, which in accordance of the wide range of natural host species and the geographical confinement to East Africa suggest that these viruses existed in East African wild plants before the introduction of sweetpotato. Subsequently, these studies provide compelling evidence that East Africa constitutes a cradle of SPFMV strain EA, SPCSV strain EA, and SPMMV. Therefore, sweet potato virus disease (SPVD) in East Africa may be one of the examples of damaging virus diseases resulting from exchange of viruses between introduced crops and indigenous wild plant species. Keywords: Convolvulaceae, East Africa, epidemiology, evolution, genetic variability, Ipomoea, recombination, SPCSV, SPFMV, SPMMV, selection pressure, sweetpotato, wild plant species Author s Address: Arthur K. Tugume, Department of Agricultural Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O Box 27, FIN-00014, Helsinki, Finland. Email: tugume.arthur@helsinki.fi Author s Present Address: Arthur K. Tugume, Department of Botany, Faculty of Science, Makerere University, P.O. Box 7062, Kampala, Uganda. Email: aktugume@botany.mak.ac.ug, tugumeka@yahoo.com
Resumo:
A new rock mass classification scheme, the Host Rock Classification system (HRC-system) has been developed for evaluating the suitability of volumes of rock mass for the disposal of high-level nuclear waste in Precambrian crystalline bedrock. To support the development of the system, the requirements of host rock to be used for disposal have been studied in detail and the significance of the various rock mass properties have been examined. The HRC-system considers both the long-term safety of the repository and the constructability in the rock mass. The system is specific to the KBS-3V disposal concept and can be used only at sites that have been evaluated to be suitable at the site scale. By using the HRC-system, it is possible to identify potentially suitable volumes within the site at several different scales (repository, tunnel and canister scales). The selection of the classification parameters to be included in the HRC-system is based on an extensive study on the rock mass properties and their various influences on the long-term safety, the constructability and the layout and location of the repository. The parameters proposed for the classification at the repository scale include fracture zones, strength/stress ratio, hydraulic conductivity and the Groundwater Chemistry Index. The parameters proposed for the classification at the tunnel scale include hydraulic conductivity, Q´ and fracture zones and the parameters proposed for the classification at the canister scale include hydraulic conductivity, Q´, fracture zones, fracture width (aperture + filling) and fracture trace length. The parameter values will be used to determine the suitability classes for the volumes of rock to be classified. The HRC-system includes four suitability classes at the repository and tunnel scales and three suitability classes at the canister scale and the classification process is linked to several important decisions regarding the location and acceptability of many components of the repository at all three scales. The HRC-system is, thereby, one possible design tool that aids in locating the different repository components into volumes of host rock that are more suitable than others and that are considered to fulfil the fundamental requirements set for the repository host rock. The generic HRC-system, which is the main result of this work, is also adjusted to the site-specific properties of the Olkiluoto site in Finland and the classification procedure is demonstrated by a test classification using data from Olkiluoto. Keywords: host rock, classification, HRC-system, nuclear waste disposal, long-term safety, constructability, KBS-3V, crystalline bedrock, Olkiluoto
Resumo:
This study addressed the large-scale molecular zoogeography in two brackish water bivalve molluscs, Macoma balthica and Cerastoderma glaucum, and genetic signatures of the postglacial colonization of Northern Europe by them. The traditional view poses that M. balthica in the Baltic, White and Barents seas (i.e. marginal seas) represent direct postglacial descendants of the adjacent Northeast Atlantic populations, but this has recently been challenged by observations of close genetic affinities between these marginal populations and those of the Northeast Pacific. The primary aim of the thesis was to verify, quantify and characterize the Pacific genetic contribution across North European populations of M. balthica and to resolve the phylogeographic histories of the two bivalve taxa in range-wide studies using information from mitochondrial DNA (mtDNA) and nuclear allozyme polymorphisms. The presence of recent Pacific genetic influence in M. balthica of the Baltic, White and Barents seas, along with an Atlantic element, was confirmed by mtDNA sequence data. On a broader temporal and geographical scale, altogether four independent trans-Arctic invasions of Macoma from the Pacific since the Miocene seem to have been involved in generating the current North Atlantic lineage diversity. The latest trans-Arctic invasion that affected the current Baltic, White and Barents Sea populations probably took place in the early post-glacial. The nuclear genetic compositions of these marginal sea populations are intermediate between those of pure Pacific and Atlantic subspecies. In the marginal sea populations of mixed ancestry (Barents, White and Northern Baltic seas), the Pacific and Atlantic components are now randomly associated in the genomes of individual clams, which indicates both pervasive historical interbreeding between the previously long-isolated lineages (subspecies), and current isolation of these populations from the adjacent pure Atlantic populations. These mixed populations can be characterized as self-supporting hybrid swarms, and they arguably represent the most extensive marine animal hybrid swarms so far documented. Each of the three swarms still has a distinct genetic composition, and the relative Pacific contributions vary from 30 to 90 % in local populations. This diversity highlights the potential of introgressive hybridization to rapidly give rise to new evolutionarily and ecologically significant units in the marine realm. In the south of the Danish straits and in the Southern Baltic Sea, a broad genetic transition zone links the pure North Sea subspecies M. balthica rubra to the inner Baltic hybrid swarm, which has about 60 % of Pacific contribution in its genome. This transition zone has no regular smooth clinal structure, but its populations show strong genotypic disequilibria typical of a hybrid zone maintained by the interplay of selection and gene flow by dispersing pelagic larvae. The structure of the genetic transition is partly in line with features of Baltic water circulation and salinity stratification, with greater penetration of Atlantic genes on the Baltic south coast and in deeper water populations. In all, the scenarios of historical isolation and secondary contact that arise from the phylogeographic studies of both Macoma and Cerastoderma shed light to the more general but enigmatic patterns seen in marine phylogeography, where deep genetic breaks are often seen in species with high dispersal potential.