Freezing and low temperature photoinhibition tolerance in cultivated potato and potato hybrids

Selostus: Perunan ja perunahybridien jäätymisen ja fotoinhibition kestävyys

Avian Evolutionary Genomics: Studies of Ficedula Flycatchers

In this thesis, different genetic tools are used to investigate both natural variation and speciation in the Ficedula flycatcher system: pied (Ficedula hypoleuca) and collared (F. albicollis) flycatchers. The molecular evolution of a gene involved in postnatal body growth, GH, has shown high degree of conservation at the mature protein between birds and mammals, whereas the variation observed in its signal peptide seems to be adaptive in pied flycatcher (I & II). Speciation is the process by which reproductive barriers to gene flow evolve between populations, and understanding the mechanisms involved in pre- and post-zygotic isolation have been investigated in Ficedula flycatchers. The Z chromosome have been suggested to be the hotspot for genes involved in speciation, thus sequencing of 13 Z-linked coding genes from the two species in allopatry and sympatry have been conducted (III). Surprisingly, the majority of Z-linked genes seemed to be highly conserved, suggesting instead a potential involvement of regulatory regions. Previous studies have shown that genes involved in hybrid fitness, female preferences and male plumage colouration are sex-linked. Hence, three pigmentation genes have been investigated: MC1R, AGRP, and TYRP1. Of these three genes, TYRP1 was identified as a strong candidate to be associated with black-brown plumage variation in sympatric populations, and hence is a strong candidate for a gene contributing to pre-zygotic isolation (IV). In sympatric areas, where pied and collared flycatchers have overlapping breeding areas, hybridization sometimes occurs leading to the production of unfit hybrids. By using a proteomic approach a novel expression pattern in hybrids was revealed compared to the parental species (V) and differentially expressed proteins subsequently identified by sequence similarity (VI). In conclusion, the Z chromosome appears to play an important role in flycatcher speciation, but probably not at the coding level. In addition the novel expression patterns might give new insights into the maladaptive hybrids.

Permanent Magnet Synchronous Machine for Parallel Hybrid Vehicle

The aim of this thesis is to describe hybrid drive design problems, the advantages and difficulties related to the drive. A review of possible hybrid constructions, benefits of parallel, series and series-parallel hybrids is done. In the thesis analytical and finite element calculations of permanent magnet synchronous machines with embedded magnets were done. The finite element calculations were done using Cedrat’s Flux 2D software. This machine is planned to be used as a motor-generator in a low power parallel hybrid vehicle. The boundary conditions for the design were found from Lucas-TVS Ltd., India. Design Requirements, briefly: • The system DC voltage level is 120 V, which implies Uphase = 49 V (RMS) in a three phase system. • The power output of 10 kW at base speed 1500 rpm (Torque of 65 Nm) is desired. • The maximum outer diameter should not be more than 250 mm, and the maximum core length should not exceed 40 mm. The main difficulties which the author met were the dimensional restrictions. After having designed and analyzed several possible constructions they were compared and the final design selected. Dimensioned and detailed design is performed. Effects of different parameters, such as the number of poles, number of turns and magnetic geometry are discussed. The best modification offers considerable reduction of volume.

Enhancing performance of paper coatings by tailor-made plastic pigments

The paper industry is constantly looking for new ideas for improving paper products while competition and raw material prices are increasing. Many paper products are pigment coated. Coating layer is the top layer of paper, thus by modifying coating pigment also the paper itself can be altered and value added to the final product. In this thesis, synthesis of new plastic and hybrid pigments and their performance in paper and paperboard coating is reported. Two types of plastic pigments were studied: core-shell latexes and solid beads of maleimide copolymers. Core-shell latexes with partially crosslinked hydrophilic polymer core of poly(n-butyl acrylate-co-methacrylic acid) and a hard hydrophobic polystyrene shell were prepared to improve the optical properties of coated paper. In addition, the effect of different crosslinkers was analyzed and the best overall performance was achieved by the use of ethylene glycol dimethacrylate (EGDMA). Furthermore, the possibility to modify core-shell latex was investigated by introducing a new polymerizable optical brightening agent, 1-[(4-vinylphenoxy)methyl]-4-(2-henylethylenyl)benzene which gave promising results. The prepared core-shell latex pigments performed smoothly also in pilot coating and printing trials. The results demonstrated that by optimizing polymer composition, the optical and surface properties of coated paper can be significantly enhanced. The optimal reaction conditions were established for thermal imidization of poly(styrene-co-maleimide) (SMI) and poly(octadecene-co-maleimide) (OMI) from respective maleic anhydride copolymer precursors and ammonia in a solvent free process. The obtained aqueous dispersions of nanoparticle copolymers exhibited glass transition temperatures (Tg) between 140-170ºC and particle sizes from 50-230 nm. Furthermore, the maleimide copolymers were evaluated in paperboard coating as additional pigments. The maleimide copolymer nanoparticles were partly imbedded into the porous coating structure and therefore the full potential of optical property enhancement for paperboard was not achieved by this method. The possibility to modify maleimide copolymers was also studied. Modifications were carried out via N-substitution by replacing part of the ammonia in the imidization reaction with amines, such as triacetonediamine (TAD), aspartic acid (ASP) and fluorinated amines (2,2,2- trifluoroethylamine, TFEA and 2,2,3,3,4,4,4-heptafluorobuthylamine, HFBA). The obtained functional nanoparticles varied in size between 50-217 nm and their Tg from 150-180ºC. During the coating process the produced plastic pigments exhibited good runnability. No significant improvements were achieved in light stability with TAD modified copolymers whereas nanoparticles modified with aspartic acid and those containing fluorinated groups showed the desired changes in surface properties of the coated paperboard. Finally, reports on preliminary studies with organic-inorganic hybrids are presented. The hybrids prepared by an in situ polymerization reaction consisted of 30 wt% poly(styrene- co-maleimide) (SMI) and high levels of 70 wt% inorganic components of kaolin and/or alumina trihydrate. Scanning Electron Microscopy (SEM) images and characterization by Fourier Transform Infrared Spcetroscopy (FTIR) and X-Ray Diffraction (XRD) revealed that the hybrids had conventional composite structure and inorganic components were covered with precipitated SMI nanoparticles attached to the surface via hydrogen bonding. In paper coating, the hybrids had a beneficial effect on increasing gloss levels.

Pricing anomalies in the Finnish stock market

The aim of this thesis is to examine whether the pricing anomalies exists in the Finnish stock markets by comparing the performance of quantile portfolios that are formed on the basis of either individual valuation ratios, composite value measures or combined value and momentum indicators. All the research papers included in the thesis show evidence of value anomalies in the Finnish stock markets. In the first paper, the sample of stocks over the 1991-2006 period is divided into quintile portfolios based on four individual valuation ratios (i.e., E/P, EBITDA/EV, B/P, and S/P) and three hybrids of them (i.e. composite value measures). The results show the superiority of composite value measures as selection criterion for value stocks, particularly when EBITDA/EV is employed as earnings multiple. The main focus of the second paper is on the impact of the holding period length on performance of value strategies. As an extension to the first paper, two more individual ratios (i.e. CF/P and D/P) are included in the comparative analysis. The sample of stocks over 1993- 2008 period is divided into tercile portfolios based on six individual valuation ratios and three hybrids of them. The use of either dividend yield criterion or one of three composite value measures being examined results in best value portfolio performance according to all performance metrics used. Parallel to the findings of many international studies, our results from performance comparisons indicate that for the sample data employed, the yearly reformation of portfolios is not necessarily optimal in order to maximally gain from the value premium. Instead, the value investor may extend his holding period up to 5 years without any decrease in long-term portfolio performance. The same holds also for the results of the third paper that examines the applicability of data envelopment analysis (DEA) method in discriminating the undervalued stocks from overvalued ones. The fourth paper examines the added value of combining price momentum with various value strategies. Taking account of the price momentum improves the performance of value portfolios in most cases. The performance improvement is greatest for value portfolios that are formed on the basis of the 3-composite value measure which consists of D/P, B/P and EBITDA/EV ratios. The risk-adjusted performance can be enhanced further by following 130/30 long-short strategy in which the long position of value winner stocks is leveraged by 30 percentages while simultaneously selling short glamour loser stocks by the same amount. Average return of the long-short position proved to be more than double stock market average coupled with the volatility decrease. The fifth paper offers a new approach to combine value and momentum indicators into a single portfolio-formation criterion using different variants of DEA models. The results throughout the 1994-2010 sample period shows that the top-tercile portfolios outperform both the market portfolio and the corresponding bottom-tercile portfolios. In addition, the middle-tercile portfolios also outperform the comparable bottom-tercile portfolios when DEA models are used as a basis for stock classification criteria. To my knowledge, such strong performance differences have not been reported in earlier peer-reviewed studies that have employed the comparable quantile approach of dividing stocks into portfolios. Consistently with the previous literature, the division of the full sample period into bullish and bearish periods reveals that the top-quantile DEA portfolios lose far less of their value during the bearish conditions than do the corresponding bottom portfolios. The sixth paper extends the sample period employed in the fourth paper by one year (i.e. 1993- 2009) covering also the first years of the recent financial crisis. It contributes to the fourth paper by examining the impact of the stock market conditions on the main results. Consistently with the fifth paper, value portfolios lose much less of their value during bearish conditions than do stocks on average. The inclusion of a momentum criterion somewhat adds value to an investor during bullish conditions, but this added value turns to negative during bearish conditions. During bear market periods some of the value loser portfolios perform even better than their value winner counterparts. Furthermore, the results show that the recent financial crisis has reduced the added value of using combinations of momentum and value indicators as portfolio formation criteria. However, since the stock markets have historically been bullish more often than bearish, the combination of the value and momentum criteria has paid off to the investor despite the fact that its added value during bearish periods is negative, on an average.

Synthesis and Characterization of Cellulose fiber-silica nanocomposites

Cellulose fiber-silica nanocomposites with novel mechanical, chemical and thermal properties have potential to be widely applied in different area. Monodispered silica nanoparticles play an important role in enhancing hybrids properties of hardness, strength, thermal stability etc. On the other hand, cellulose is one of the world’s most abundant and renewable polymers and possesses several unique properties required in many areas and biomedicine. The aim of this master thesis is to study if silica particles from reaction of sodium silicate and sulphuric acid can be adsorbed onto cellulose fiber surfaces via in situ growth. First, nanosilica particles were synthesized. Effect of pH and silica contents were tested. In theoretical part, introduction of silica, methods of preparation of nanosilica from sodium silicate, effect factors and additives were discussed. Then, cellulose fiber-silica nanocomposites were synthesis via route from sodium silicate and route silicic acid. In the experiment of route from sodium silicate, the effects of types of sodium silicate, pH and target ratio of silica to fiber were investigated. From another aspect, the effects of types of sodium silicate, fiber concentration in mixture solution and target ratio of silica to fiber were tested in the experiment of route from silicic acid. Samples were investigated via zeta potential measurement, particle size distribution, ash content measurement and Scanning Electron Microscopy (SEM). The Results of the experiment of preparing silica sol were that the particle size of silica sol was smaller prepared in pH 11.7 than that prepared in pH 9.3. Then in the experiment of synthesis of cellulose fiber-silica nanocomposites, it was concluded that the zeta potential of all the samples were around -16 mV and the highest ash content of all the samples was only 1.4%. The results of SEM images showed only a few of silica particles could be observed on the fiber surface, which corresponded to the value of ash content measurement.

Pojkar kan visst skriva! : skrivkompetenser på nationellt prov i svenska i årskurs tre i Sverige

10-year old boys are writing texts in a National Test in the spring of 2009. The aim of this study is to increase knowledge in and understanding of boys’ writing skills through description, analysis and interpretation of the texts produced by the boys in the National Test in Swedish for junior level year three, taken in Sweden in 2009. The material consists of texts produced by boys and is focused on their ability to write. Through avoiding relating to texts produced by girls, it is possible to search, review, interpret and observe without simultaneously comparing the two genders. The aim of the test is to measure writing proficiency from a normative perspective, while I am investigating content, reception, awareness, and other aspects relevant when producing text. Genres are described through the instruction given in the test, which defines the work that takes place in the classroom and thereby my approach to the analysis. The latter is focused on finding patterns in the competence of the students rather than looking for flaws and limitations. When competence is searched for beyond the relationship to syllabi or the demands of the test in itself, the boys’ texts from the test provide a general foundation for investigating writing proficiency. Person, place and social group have been removed from the texts thereby avoiding aspects of social positioning. The texts are seen from the perspective of 10-year old boys who write texts in a National Test. The theoretical basis as provided by Ivaničs (2004; 2012) offers models for theory on writing. A socio-cultural viewpoint (Smidt, 2009; Säljö, 2000) including literacy and a holistic view on writing is found throughout. By the use of abdicative logic (see 4.4) material and theory work in mutual cooperation. The primary method hermeneutics (Gadamer 1997) and analytical closereading (Gustavsson, 1999) are used dependent on the requirements of the texts. The thesis builds its foundation through the analysis from theoretically diverse areas of science. Central to the thesis is the result that boys who write texts in the National Test, are able to write in two separate genres without conversion or the creating hybrids between the two. Furthermore, the boys inhibit extensive knowledge about other types of texts, gained from TV, film, computers, books, games, and magazines even in such a culturally bound context as a test. Texts the boy has knowledge of through other situations can implicitly be inserted in his own text, or be explicitly written with a name of the main character, title, as well as other signifiers. These texts are written to express and describe what is required in the topic heading of the test. In addition other visible results of the boys’ ability to write well occur though the multitude of methods for analysis throughout the thesis which both search, and find writing competence in the texts written by the boys.

Messiaanista identiteettiä etsimässä

Kirjallisuusarvostelu