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Now showing items 4523-4542 of 24408
  • F. 
    Lahti, Leo (1975)
  • F. 
    Leino, Lasse (1952)
  • F. 
    Autio, Risto (1965)
  • F. 
    Liukko, Suvikki (1968)
  • F. 
    Liukko, Suvikki (1968)
  • F. 
    Lönnbohm, O. A. (1881)
  • F. 
    Nissi, Eliisa (1972)
  • F. 
    Oksa, Marita (1982)
  • F. 
    Seppälä, Sirkka (1956)
  • F. 
    Hammas, Toivo (1929)
  • F. 
    Heinonen, Aune (1945)
  • F. 
    Hiisku, Aune (1955)
  • Hautsalo, Juho (2013)
    The objective of this study was to develop functional method for producing doupled-haploid plants for faba bean. Microspore culture is an advanced method to produce doubled-haploids and it is based on the totipotent nature of plant cells, since even a microspore, which is an immature pollen cell with haploid genome, can develop into a plant. This plant is either haploid or doupled haploid depending on whether there has been chromosome doubling or not and because the chromosomes either do not have pairs or the pairs are pure copies of each other, the plant is completely homozygous. Doubled haploids are already used in breeding programs with several crops such as wheat, barley and oilseed rape. Faba bean is an important legume for food, feed and crop rotation. Together with other legumes it has the potential to replace soybean imports entirely in Finland. Faba bean yield stability and anti-nutritional factors restrain its use and active breeding is required to improve the crop. In Finland, where pea and faba bean are the only grain legumes actively cultivated, the breeding of faba bean has been recently reactivated and its objectives are earliness, higher yield, protein content and improved quality factors. Big bottle neck in faba bean breeding is the creation of pure homozygote lines because the partial cross-breeding in the species sets restrains for the procedure. In this study promising pea and chick pea protocols that were developed in 2009 and an efficient rapeseed protocol were applied with faba bean. The interaction of various stress treatments and two different induction media with five genotypes of faba bean on microspore culture were analysed. Pro-embryos and cell divisions were observed from the cultures. Heat shock was the most effective stress treatment. Effects of density and induction medium were high and cultivar’s low tannin content seemed to impact positively to induction efficiency. These results suggest that for faba bean microspore culture is as suitable method as anther culture is and that there is hope to produce doubled-haploid faba beans in the future.
  • Igna, Cornel (Helsingin yliopisto, 2013)
    Previous research has shown that negative affectivity (NA) and lifestyle associate with CVD/CHD risk factors. In the present thesis the relationships between some key indicators of NA (depressive symptoms, vital exhaustion, hopelessness, and anger expression) and lifestyle factors, body mass index, serum lipids and blood pressure were investigated. All the four studies that constitute this investigation were based on data from the Helsinki Metabolic Syndrome Prevention Trial, which was an uncontrolled preventive trial aimed at improving prevention of metabolic syndrome, type 2 diabetes and cardiovascular diseases by developing a practical method for primary health care. The main idea was to screen and identify men with cardiovascular risk clustering and give them individual counselling based on their risk profile. Evaluation of risk was based on a Risk Index that included five factors: body mass index, total serum cholesterol, blood pressure (systolic and diastolic), smoking habits, and physical inactivity. The participants in the screening were 40-55 year-old-men residing in the north-east Helsinki. Data collection was carried out between May 2001 and June 2004, and all the participants were asked to answer questionnaires dealing with lifestyle factors and psychosocial risk factors. Study nurses from the Helsinki Heart District interviewed all the participants and recorded basic biomedical measurements (e.g. blood pressure, waist circumference, weight). The size of the sample in studies I-IV was 893, 705, 444, and 710, respectively. The findings of this study indicate that depressive symptoms had a consistent statistically significant correlation with adverse lifestyle factors and triglycerides. For cholesterol fractions, path analyses indicated the parallel existence of two main pathways: from depression through the adverse health behaviour to an unfavourable cholesterol fraction balance, and from depression through a direct, probably physiological, link to favourable cholesterol levels.
  • Mustamäki, Milla (2013)
    The World Trade Organization (WTO), established in 1994, has been criticized for not sufficiently accommodating other values of international law such as the environment or human rights. This study examines interaction and possible collisions between the WTO and other special regimes of international law from the viewpoint of the WTO dispute settlement mechanism. Both normative and jurisdictional conflicts are studied. The purpose is to analyze the means available in international law to solve these conflicts and whether they actually are working. There is no hierarchy between international tribunals and no codified rules on how to solve conflicts of jurisdiction. Treaty clauses may be of some help, but often the clauses are too vague to offer any guidance in practical situations. Traditional principles governing jurisdiction, such as res judicata and lis pendens, might solve conflicts inside one regime, but they seem to work poorly in conflicts of jurisdiction between different special regimes. Parallel proceedings can be avoided if one of the tribunals shows deference to the other, or if the parties manage to agree on the relevant tribunal. Paradoxically, politics and diplomacy seems to play an important role in solving conflicts of jurisdiction between international tribunals. Normative conflicts can be defined either narrowly or broadly. This study advocates a broad definition of conflict in order to realize conflicts between obligations and permissions, and to avoid solving conflicts by merely defining them narrowly. Conflicts can be avoided through interpretation in the light of other rules of international law applicable between the parties, also known as systemic integration. Systemic integration could be especially useful in smoothing friction in the interaction between the WTO and other special regimes. However, so far the WTO panels and the Appellate Body have not made use of systemic integration to the extent possible. Actual conflict rules become necessary when interpretation fails in providing harmony between two conflicting norms. It is concluded that conflict rules, such as lex posterior and lex specialis, can be of use when solving conflicts inside one regime, but their applicability to conflicts between special regimes is problematic. Possible conflicts between peremptory norms and WTO law are also discussed. It is concluded that solving jurisdictional and normative conflicts has more to do with political decision-making than with the application of legal rules. It is suggested that the interaction between the WTO and other special regimes could further be enhanced by a broad definition of conflict and the utilization of systemic integration to its full extent.
  • Nandelstadh, Casper von (2003)
    Studien har två syften. För det första att ta reda på varför fackförbund väljer att inte godta det av centralförbunden och regeringen överenskomna inkomstpolitiska avtalet. För det andra att bedöma om denna strategi som kallas friåkning leder till ett för fackförbundet fördelaktigare kollektivavtal. Fackförbunden i denna studie är Elbranschens fackförbund som valde friåkandet för telebranschen, Byggnadsförbundet för husbyggnadsbranschens del och Gummi- och läderarbetarnas förbund i fråga om bildäcks- och gummiindustrin. Det inkomstpolitiska avtal förbunden hade att ta ställning till gällde åren 1992–1993. Studiens referensram har inspirerats av Leif Lewins teorier om den rationella aktören som han presenterat i bland annat Ideologi och strategi. Svensk politik under 100 år. Jag har också presenterat det systemteoretiska perspektivet. De tre friåkarförbunden förenas ideologiskt genom att de alla tre enligt sina stadgar strävar efter att förvandla produktionssystemet till socialistiskt. Men när det gäller de specifika motiveringarna just denna gång skiljer de sig åt. Gummi- och läderarbetarnas fackförbunds syn på löneutvecklingen i sina branscher var den att inga löneglidningar förekommer, alltså var det viktigt att avtala om löneförhöjningarna. Byggnadsförbundet uppgav en förnyelse av förtroendemannaavtalet som orsak till friåkandet och Elbranschens fackförbund ansåg att telebranschen hamnat på efterkälken i avlöningen jämfört med övriga löntagare. År 1991 såg de sin chans att korrigera detta då omsättningen i telebranschen ökat. Samhällsekonomin i övrigt upplevde samtidigt en dramatisk konjunkturnedgång. Lyckades fackförbunden förbättra sina kollektivavtal genom friåkandet? Även här skiljer sig fackförbunden från varandra. Elbranschens fackförbund uppnådde de största framgångarna och det är inget tvivel om att friåkandet lönade sig för förbundet och dess medlemmar. Gummi- och läderarbetarnas förbund lyckades höja vissa tillägg i båda branscherna och inom gummiidustrin gavs huvudförtroendemännen rätt att ägna all arbetstid för förtroendeuppdraget. Byggnadsförbundets resultat är däremot svårare att bedöma. Visserligen nåddes ett nytt förtroendemannaavtal för husbyggnadsbranschen. Men snarast var det väl en avvärjningsseger där facket lyckades förhindra de av arbetsgivarna tänkta försämringarna. Eftersom friåkandet inte medförde några direkta kostnader för fackförbundens medlemmar annat än i telebranschen där övertidsförbud rådde i tio dagar kan man konstatera att det lönade sig att friåka inför avtalen år 1992–1993.
  • Koskinen, Mikko (Helsingin yliopisto, 2014)
    Dendritic spines are small bulbous protrusions extending from dendritic shafts of neurons. These compartments house most of the postsynaptic terminals of excitatory synapses in the mammalian central nervous system. Dendritic spines are formed during early development and their density and morphology undergoes significant changes during maturation. After maturation dendritic spines are not static structures but display constant changes in their morphology and stability. The shape and size of dendritic spines have been linked to synaptic transmission, coupling the form of spines to neuron function. Several neurological diseases and disabilities are characterized by abnormal spine density and morphology. The main structural component of the dendritic spines is the actin filament, F-actin. Actin filaments are dynamic polymers of the monomeric protein actin. The filaments are constantly turning over and reorganizing. Both processes are regulated by actin binding proteins. All structural changes and the maintenance of dendritic spines are dependent on actin dynamics. Current research indicates that the dynamics of actin filaments do not change following spine maturation. Maturation does lead to a decrease in the movement of spines and an increase in stability, indicating changes in F-actin dynamics. In this study I have shown that the dynamics of F-actin do change during maturation. The stable pool of F-actin increases in size and the turnover of the dynamic pool increases. One of the actin binding proteins with a potential to regulate actin stabilization is myosin IIb, a motor protein with capabilities to bind F-actin and to introduce contractility into the filament network. Myosin IIb has been shown to regulate dendritic spine development, size and shape and play a role in memory consolidation. In this study I have shown that myosin IIb regulates dendritic spine F-actin via two distinct mechanisms. Myosin IIb can bind F-actin and stabilize it without affecting the turnover of the dynamic filaments. Myosin IIb-mediated contractility on the other hand can facilitate the turnover of the dynamic filaments. These findings help us to understand the molecular mechanism behind dendritic spine structure regulation and possibly in the future how it is related to synaptic transmission and different pathological states. Due to their small size, dendritic spines pose unique challenges for the study of actin dynamics. Most of the available methods are based on advanced fluorescence microscopy. In this study I have made a critical evaluation of the methods used to measure F-actin turnover in dendritic spines and the analysis of the data. I have also developed a novel approach to use fluorescence anisotropy to measure the level of actin bundling. The method has been previously applied to measure actin polymerization. My findings have led to the conclusion that in actin-dense compartments, such as the dendritic spines, fluorescence anisotropy reflects actin bundling rather than polymerization and that conclusions based on earlier research using similar techniques should be re-evaluated.
  • Pyykkönen, Perttu (Helsingin yliopisto, 2006)
    The purpose of the study was to analyse factors affecting the differences in land prices between regions. The key issue was to find out the policy effects on farmland prices. In addition to comprehensive literature review, a theoretical analysis as well as modern panel and spatial econometric techniques were utilized. The study clearly pointed out the importance of taking into account the possible spatial dependence. The data were exceptionally large, comprising more than 6 000 observations. Thus, it allowed a thorough econometric estimation including the possibility to take into account the spatial nature of the data. This study supports the view that there are many other factors that affect farmland prices besides pure agricultural returns. It was also found that the support clearly affects land prices. However, rather than assuming the discount rates for support and market returns to be similar, the rough analysis refers to the discount rate for support being a little lower. If this were true it would indicate that farmers rely more on support income than market returns. The results support the view presented in literature that land values are more responsive to government payments when these payments are perceived to be permanent. An important result of this study is that the structural differences between regions and the structural change in agriculture seemed to have a considerable role in affecting land prices. Firstly, the present structure affects the competition in the land market: the more dense farms are in the region the more there are potential buyers, and the land price increases. Secondly, the change in farm structure (especially in animal husbandry) connected to the policy changes that increase area-based support affects land prices. The effect comes from two sources. Growing farms need more land for the manure, and the proportion of retiring farmers may be lower. The introduction of the manure density variable proved to be an efficient way to aggregate the otherwise very difficult task of taking into account the environmental pressure caused by structural change in animal husbandry. Finally, infrastructure also has a very important role in determining the price level of agricultural land. If other industries are prospering in the surrounding area, agricultural viability also seems to improve. The non-farm opportunities offered to farm families make continuing and developing farming more tempting.
  • Wang, Lei (Helsingin yliopisto, 2011)
    This dissertation is a broad study of factors affecting perceptions of CSR issues in multiple stakeholder realms, the main purpose being to determine the effects of the values of individuals on their perceptions regarding CSR. It examines perceptions of CSR both at the emic (observing individuals and stakeholders) and etic levels (conducting cross-cultural comparison) through a descriptive-empirical research strategy. The dissertation is based on quantitative interview data among Chinese, Finnish and US stakeholder groups of industry companies (with an emphasis on the forest industries) and consists of four published articles and two submitted manuscripts. Theoretically, this dissertation provides a valuable and unique philosophical and intellectual perspective on the contemporary study of CSR `The Harmony Approach to CSR'. Empirically, this dissertation does values assessment and CSR evaluation of a wide variety of business activities covering CSR reporting, business ethics, and three dimensions of CSR performance. From the multi-stakeholder perspective, this dissertation use survey methods to examine the perceptions and stakeholder salience in the context of CSR by describing, comparing the differences between demographic factors as well as hypothetical drivers behind perceptions. The results of study suggest that the CSR objective of a corporation's top management should be to manage the divergent and conflicting interests of multiple stakeholders, taking others than key stakeholders into account as well. The importance of values as a driver of ethical behaviour and decision-making has been generally recognized. This dissertation provides more empirical proof of this theory by highlighting the effects of values on CSR perceptions. It suggests that since the way to encourage responsible behaviour and develop CSR is to develop individual values and cultivate their virtues, it is time to invoke the critical role of moral (ethics) education. The specific studies of China and comparison between Finland and the US contribute to a common understanding of the emerging CSR issues, problems and opportunities for the future of sustainability. The similarities among these countries can enhance international cooperation, while the differences will open up opportunities and diversified solutions for CSR in local conditions.
  • Lindholm, Agneta (Helsingin yliopisto, 2010)
    Bacteria are utilized for the production of many heterologous proteins, including industrially important enzymes, pharmaceuticals and vaccines. This has resulted in an extensive research on the steps along the protein production pathway in both Gram-negative and Gram-positive bacteria, in order to understand the mechanisms involved and to develop new and better tools for optimal production. However, there is still a lack in our understanding regarding bacterial protein synthesis and the production of every target protein has to be experimentally evaluated. Even so, satisfying quantity and quality of many produced proteins have not been reached. In some applications, including industrial production of enzymes, the aim is usually to produce high yields of the target protein. This can best be accomplished if the protein is secreted into the culture medium from where it can be purified. In other applications, e.g. bacterial delivery of an antigen to mucosal surfaces, the requirement to reach the maximum yield might not be the main goal. Instead, the production system could be optimized in order to display the target antigen on the bacterial surface, from where it could be presented to the immune system on mucosal surfaces. During the last decade, there has been an increasing interest to utilize non-pathogenic and probiotic bacteria as vehicles for the delivery of therapeutic and prophylactic molecules to mucosal surfaces. Especially, lactic acid bacteria (LAB) with putative probiotic properties are interesting candidates. In this work, the secretion and surface display of heterologous proteins in the food-grade LAB Lactococcus lactis was studied. In the first part, the protein secretion pathway of L. lactis was complemented with the extracellular chaperone PrsA from Bacillus subtilis. With the nisin-controlled gene expression (NICE) system, PrsA was produced in an active form in L. lactis and its function was similar to its function in B. subtilis. That is, PrsA increased the secretion yield of a PrsA-target protein, whereas it had no effect on the secretion of a PrsA-nontarget protein. Even though the secretion yield increased, some of the PrsA-target protein remained partly trapped on the trans side of the cytoplasma membrane in an unprocessed form, indicating a problem at late stages of secretion. In the second part, the secretion efficiency and surface display of different proteins were optimized. The target proteins were produced as translational fusions with the lactococcal proteinase PrtP and the lactococcal autolysin AcmA cell wall binding repeats. Different fragments, spanning the H- and W-domains of PrtP were utilized as spacers, to extend the target protein through the cell wall to the bacterial surface. With this method, two target proteins were successfully surface displayed and recognized by their respective antibodies in whole-cell enzyme-linked immunosorbent assay studies. Escherichia coli beta-lactamase (Bla) was mainly used as an easily detectable reporter protein when the first constructs were made, whereas the Lactobacillus brevis S-layer (SlpA) receptor binding domain rendered the nonadhesive L. lactis cell the ability to adhere to fibronectin and the human intestinal epithelial cell line, Intestine 407. In the third part of the study, the aim was to employ the surface display system to construct a live bacterial mucosal vaccine against porcine post-weaning diarrhoea and oedema disease, caused by F18-positive E. coli. The secretion efficiency of the receptor-binding domain of FedF, the adhesin of F18 fimbriae, was evaluated by translational fusion of FedF-PrtP to either one of the signal peptides of L. lactis Usp45 or L. brevis SlpA. Expression in the NICE system resulted in a larger protein yield with the SlpA signal peptide, which was used in further studies. Purified secreted FedF-protein was able to bind to isolated porcine epithelial cells. For efficient surface display of the receptor binding domain of FedF several parameters were evaluated, including length of FedF protein, length of PrtP spacer, type of cell wall anchor, and host background (wild type L. lactis NZ9000 and an NZ9000htrA mutant). The strongest adhesion to isolated porcine intestinal epithelial cells was attained with a construct comprising 42 amino acid residues FedF adhesin, 516 amino acid residues PrtP spacer, and the AcmA cell wall anchor, produced in the NZ9000htrA mutant. In the fourth study, the FedF surface display system was further developed for constitutive expression. For this, a set of artificial promoters were synthesized and used to express the gene fusion. With the strongest constitutive promoter, L. lactis cells surface displayed FedF to the same extent as with optimized nisin induction, indicating the attainment of an optimal constitutive expression level for the construct.