Browsing by Title

Sort by: Order: Results:

Now showing items 4612-4631 of 24762
  • 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.
  • Kaukomaa, Timo (Helsingin yliopisto, 2015)
    This study examines facial expressions in naturally occurring face-to-face interaction. The focus is on how facial expressions (e.g., smiles and frowns) are part of the collaborative construction and modification of shared emotional stances between speakers and hearers. The data corpus of this study consists of five recorded dyadic Finnish conversations over lunch between individuals who were familiar with each other. The conversations were recorded with three video cameras: two cameras recorded the participants facial expressions and upper bodies and one camera the overall situation. The method of this study is conversation analysis, which makes it possible to examine how participants use their facial expression, move-by-move or turn-by-turn, in the joint negotiation processes of shared emotional stances. The dissertation consists of three original articles and an introduction. In the introduction, I lay out the central concepts and the perspective of the study, describe the data and method, and provide an overview and short examples of the results of the study. I also discuss at a more general level the ways in which my study contributes to earlier studies on embodied socio-emotional communication, and to our understanding of social interaction and social life. The analysis highlights the important role facial expressions have in construction and modification of the public emotional sphere of conversation. The emotional sphere is in continuous transformation, as the participants collaboratively negotiate their situational relationship and interpersonal (in)congruence with regard to the activity at hand. The articles 1 and 2 examine how speakers turn initial facial expression (a smile or a frown) contributes to the action of the utterance it foreshadows and to the larger sequential environment. The results show that the interactional trajectories of these turn-opening facial expressions vary substantially: smiles are first steps to a shared moment of positive or humorous stance, whereas frowns initiate a problem turn that creates momentary distance between participants. The article 3 demonstrates the ways in which recipients facial expression may shift the emotional stance of the speaker s utterance. The recipient s facial expressions play a major role in the collaborative modification of shared emotional stance. They do not simply mirror the speaker s stance or display understanding of the speaker s talk; rather, they perform well-timed systematic operations on the projected course of the talk. The contribution of the article is to show how speakers and hearers work in collaboration using subtle and well-timed facial (and other) expressions of emotion in order to negotiate, move-by-move, the emotional stance(s) that they will share. This study reveals the significance of facial expressions in communicative actions and in the regulation of situational affective relationship between speakers and hearers in mundane interactions. These processes resonate with the larger social structures and the reproduction of micro-social order.
  • 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.
  • Santala, Johanna (Helsingin yliopisto, 2015)
    The spraing symptoms on potato tubers caused by Potato mop-top virus (PMTV) are considered as one of the most important quality problems in potato production in the Nordic countries. PMTV has a tripartite single stranded positive sense RNA genome. RNA-RdRp encodes the viral replicase. PMTV-CP codes for a coat protein (CP) and a read through part of CP associated with the vector transmission. RNA-TGB encodes three movement related triple gene block proteins (TGBp) and an 8 kDa cysteine rich protein (8K) implicated as suppressor of RNA silencing. The aim of this study was to find new host and viral factors affecting PMTV infection and detection. As only few PMTV sequences were available in databanks prior to this study, 28 PMTV isolates obtained from symptomatic and asymptomatic potato tubers were partially sequenced. Two distinguishable types of RNA-CP and RNA-TGB were found, each showing only little genetic variability. Occurrence of tuber symptoms did not correlate with the types of PMTV RNA but seemed to depend on potato cultivar and environmental conditions. Indeed, in some cultivars almost all PMTV infections were asymptomatic. Potato sprouts grown in dark were found to contain high titers of PMTV and can be used to test potatoes for PMTV. However, viral titers decreased rapidly in sprouts exposed to light. Accumulation of PMTV specific small interfering RNAs (siRNA) in both dark grown and light exposed sprouts indicated that RNA silencing was acting against the virus in the sprouts. Moreover, the amount of viral siRNA, as opposed to viral RNA, did not decrease in the light-exposed sprouts indicating that RNA silencing was enhanced in the light exposed sprouts. PMTV TGBp1 was found, and PMTV 8K confirmed, to act as weak suppressor of silencing. PMTV TGBp3 interacts with TGBp2 to target viral ribonucleoprotein complexes to plasmodesmata and further to adjacent cells, but TGBp2 and TGBp3 are recycled through endocytosis. PMTV TGBp3 was found to be phosphorylated on two tyrosine residues, both of which are located within tyrosine based sorting motifs implicated in endocytosis. Mutation of one of the sites led to strengthening of the TGBp2-TGBp3 interaction and restricted the virus to the originally infected cell. Therefore, tyrosine phosphorylation of TGBp3 seemed to affect PMTV infection by regulating the interaction between TGBp2 and TGBp3. According to this study, the current reliance on symptoms in seed potato inspections for PMTV is unreliable and risks spreading the virus to new fields. Light was found to accelerate antiviral silencing in sprouts, which may explain why PMTV and its symptoms are rarely detected in aboveground parts of potato plants. Tyrosine phosphorylation of TGBp3 marked the first evidence that viral proteins can be tyrosine-phosphorylated in plants. This find could offer means for breeding PMTV resistant potato cultivars.