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  • Bäckman, Stefan (2008)
    The purpose of this study was to evaluate intensity, productivity and efficiency in agriculture in Finland and show implications for N and P fertiliser management. Environmental concerns relating to agricultural production have been and still are focused on arguments about policies that affect agriculture. These policies constrain production while demand for agricultural products such as food, fibre and energy continuously increase. Therefore the importance of increasing productivity is a great challenge to agriculture. Over the last decades producers have experienced several large changes in the production environment such as the policy reform when Finland joined the EU 1995. Other and market changes occurred with the further EU enlargement with neighbouring countries in 2005 and with the decoupling of supports over the 2006-2007 period. Decreasing prices a decreased number of farmers and decreased profitability in agricultural production have resulted from these changes and constraints and of technological development. It is known that the accession to the EU 1995 would herald changes in agriculture. Especially of interest was how the sudden changes in prices of commodities on especially those of cereals, decreased by 60%, would influence agricultural production. The knowledge of properties of the production function increased in importance as a consequence of price changes. A research on the economic instruments to regulate productions was carried out and combined with earlier studies in paper V. In paper I the objective was to compare two different technologies, the conventional farming and the organic farming, determine differences in productivity and technical efficiency. In addition input specific or environmental efficiencies were analysed. The heterogeneity of agricultural soils and its implications were analysed in article II. In study III the determinants of technical inefficiency were analysed. The aspects and possible effects of the instability in policies due to a partial decoupling of production factors and products were studied in paper IV. Consequently connection between technical efficiency based on the turnover and the sales return was analysed in this study. Simple economic instruments such as fertiliser taxes have a direct effect on fertiliser consumption and indirectly increase the value of organic fertilisers. However, fertiliser taxes, do not fully address the N and P management problems adequately and are therefore not suitable for nutrient management improvements in general. Productivity of organic farms is lower on average than conventional farms and the difference increases when looking at selling returns only. The organic sector needs more research and development on productivity. Livestock density in organic farming increases productivity, however, there is an upper limit to livestock densities on organic farms and therefore nutrient on organic farms are also limited. Soil factors affects phosphorous and nitrogen efficiency. Soils like sand and silt have lower input specific overall efficiency for nutrients N and P. Special attention is needed for the management on these soils. Clay soils and soils with moderate clay content have higher efficiency. Soil heterogeneity is cause for an unavoidable inefficiency in agriculture.
  • Rudanko, Mikko (2015)
    Pro gradu -tutkielmassani tarkastellaan ja vertaillaan rikosoikeudellista tahallisuutta ja sen alarajaa eri valtioiden oikeusjärjestelmissä, erityisesti kahden vakavan rikostyypin, seksuaali- ja henkirikosten kohdalla. Tutkielmaani varten olen keskittynyt tarkastelemaan ja vertailemaan Suomen ja Ruotsin, Saksan ja Alankomaiden sekä Englannin ja Yhdysvaltojen oikeusjärjestelmissä käytettyä rikosoikeudellista tahallisuutta käsitteineen sekä näissä maissa rangaistavaksi säädettyjä tahallisia seksuaali- ja henkirikoksia niiden tunnusmerkistössä kuvaillun teon tekijän tahallisuudelta edellyttämine vaatimuksineen. Tutkielmassani olen vertaillut tahallisuutta muun muassa lapseen kohdistuvissa seksuaalirikoksissa, HIV-tartuntaan liittyvissä rikoksissa sekä niin sanottua venäläistä rulettia koskevissa henkirikoksissa. Tahallisuuden alarajalla on usein hyvin merkityksellinen asema teon rikosoikeudellisen arvioinnin osalta. Kuten olen tutkielmassani havainnut, pääsääntö rikosoikeudessa usein on, että teot ovat rangaistavia vain tahallisina. Osa teoista on rangaistavia myös tuottamuksellisina, esimerkiksi toisen henkilön surmaaminen ilman tahallisuutta on silti tuomittavissa kuolemantuottamuksena. Englannissa osa rikoksista on jopa säädetty ankaran vastuun alaisiksi, jolloin jo pelkkä laissa kuvatun teon suorittaminen riittää rikosvastuuseen ilman erityisiä tietoisuus- tai tahtovaatimuksia. Tällaisia tekoja ovat muun muassa seksuaalirikokset alle 13- vuotiaita lapsia kohtaan. Tarkastelemissani oikeusjärjestelmissä useimmista teoista ei kuitenkaan ole säädetty rangaistavaksi tällaisia tahallisuutta alempia vastineita, jolloin tahallisuuden alaraja on myös rikosoikeudellisen vastuun alaraja ja sen merkitys korostuu. Tarkastelemissani oikeusjärjestelmissä tahallisuuden alarajalla on omat painopisteensä tietoisuuden ja tahtomisen osalta. Erityisesti Saksassa on esitetty alarajasta erilaisia teorioita, joista nykyään vallassa on korkeimman tuomioistuimen BGH:n käyttämä malli, jossa lähes mikä tahansa todennäköisyys riittää, jos tekijä on hyväksynyt siihen liittyvän seurauksen. Henkirikoksissa alaraja on kuitenkin korkeammalla. Alankomaissa on painotettu tilastollisia todennäköisyyksiä ja asetettu esimerkiksi HIV-tapauksista annettaville tuomioille korkeampi kynnys kuin Saksassa, mutta vaadittu todennäköisyys on kuitenkin alempi kuin Suomessa. Englannissa on annettu moraalisille ja muille lain ulkopuolisille sosiaalisille ulottuvuuksille selkeästi enemmän painoarvoa kuin muissa tarkastelemissani maissa. Englannissa ja Yhdysvalloissa käytetty recklessness-käsite myös vastaa vain osittain muiden tarkastelemieni maiden dolus eventualis -tahallisuuden tasoa. Ruotsi on siirtynyt 2000-luvulla käyttämään tekijän välinpitämättömyyteen perustuvaa tahallisuutta, josta Suomessakin on ollut keskustelua. Suomen korkein oikeus on kuitenkin pitäytynyt ratkaisuissaan siinä, että tekijän tulee olla mieltänyt sekä seuraus että olosuhteet varsin todennäköisiksi.
  • Xu, Enjun (Helsingin yliopisto, 2015)
    Regulation of cellular homeostasis is crucial for proper development, survival, defense responses, programmed cell death and ultimately survival. Maintaining cellular homeostasis requires tight regulation of multiple highly interactive signaling pathways. The apoplast lies at the frontier between the cell and the environment, where the plant perceives environmental cues. Since the apoplast is also a site for cell-to-cell communication, it has an important role in mediating plant-environment interactions. Reactive oxygen species (ROS) are known as both toxic agents and indispensable signaling molecules in all aerobic organisms. A ROS burst in the apoplast is one of the first measurable events produced in response to different biotic and abiotic stresses, eventually leading to the initiation of signal transduction pathways and altered gene expression. Apoplastic ROS signaling is well known to dynamically coordinate multiple signaling pathways in the activation of defense responses in plants. Dissection of the signaling crosstalk within such a signaling network could therefore reveal the molecular mechanisms underlying defense responses. Treatments with ozone (O3) have been adopted as an efficient tool to study apoplastic ROS signaling. Plants exposed to O3 trigger a ROS burst in the apoplast and induce extensive changes in gene expression and alteration of defense hormones, such as salicylic acid (SA), jasmonic acid (JA), and ethylene. Genetic variation in O3 sensitivity among Arabidopsis thaliana accessions or mutants highlights the complex genetic architecture of plant responses to ROS. To gain insight into the genetic basis of apoplastic ROS signaling, a recombinant inbred line (RIL) population from a reciprocal cross between two Arabidopsis accessions C24 (O3 tolerant) and Tenela (O3 sensitive) was used for quantitative trait loci (QTL) mapping. Through a combination of QTL mapping and transcriptomic analyses in the response to apoplastic-ROS treatment, three QTL regions containing several potential candidate genes were identified in this study. In addition, multiple mutants with varying O3-sensitivities were employed to dissect the signaling components involved in the early apoplastic ROS signaling and O3-triggered cell death. A combination of global and targeted gene expression profiling, genetic analysis, and cell death assays was performed to dissect the contribution of hormone signaling and various transcription factors to the regulation of apoplastic ROS-triggered gene expression and cell death. The contributions of SA, JA and ethylene were assessed through analysis of mutants deficient in these hormones, mutants with constitutively activated hormone signaling and the exogenous application of hormones. Plants with elevated SA levels were found to be associated with an attenuated O3 response, whereas simultaneous elimination of SA-dependent and SA- independent signaling components enhanced the response to apoplastic ROS treatment. JA could act as both a positive and negative modifier of apoplastic ROS signaling, which was enhanced when ethylene signaling was also impaired. However, transcriptome analysis of a triple mutant deficient in SA, JA and ethylene revealed that these hormones signaling only contributed part (about 30%) of early-apoplastic ROS-triggered changes in gene expression, suggesting multiple signaling pathways could be required to regulate the apoplastic ROS response via combinatorial or overlapping mechanisms.
  • Saad, Elyana (Helsingin yliopisto, 2015)
    The relationship between mental representations based on external visual percepts (i.e., information held in short-term memory or via mental imagery) and the encoding of visual input remains unsettled. What stimulates this debate is the share of overlapping neural resources between visual short-term memory (VSTM), mental imagery and visual perception in the realm of the early visual cortex (EVC). This overlap raises a number of questions: how do the internal memory and imagery representations affect the perception of incoming visual information? What happens to imagery and VSTM abilities when cognitive resources need to be shared with the encoding of visual input? In short: how do visual memory/imagery and visual perception interact? This work addressed these questions by the use of behavioral paradigms coupled with transcranial magnetic stimulation (TMS) in situations where the encoding of the visual percept (measured via the tilt after effect (TAE) magnitude) happens either simultaneously or subsequently to holding information in VSTM/imagery. Therefore, when VSTM and the encoding of external input occurred concurrently, VSTM maintenance was found to inhibit visual encoding, reflected as a reduction of the TAE. Using TMS, it was shown that this inhibition takes place at the level of EVC. This reduction was found when the VSTM content matched the visual input, and when they were incongruent. However, when the encoding of external input occurred after VSTM maintenance phase had ended, VSTM maintenance was found to facilitate the former when the VSTM content matched the visual input. The subjective strength and the contrast of VSTM and mental imagery content (as reported by participants) affect visual detection of a briefly presented masked target. The reported visual contrast was positively associated with reporting target presence for both VSTM and mental imagery, in other words, inducing a more liberal bias. However, a differential effect was found for the subjective strength of the representations. Whereas the subjective VSTM strength was positively associated with the visual detection of the target, the opposite effect was observed for imagery. Finally, TMS applied at the EVC revealed a partial dissociation in the neural basis of VSTM and mental imagery by inducing delayed responses for the former selectively. Thus, while VSTM and mental imagery share neural resources, their neural mechanisms are partly dissociable at the level of early visual cortex.
  • Venäläinen, Salla (Helsingin yliopisto, 2010)
    Continuous growth in the number of immigrant students has changed the Finnish school environment. The resulting multicultural school environment is new for both teachers and students. In order to develop multicultural learning environments, there is a need to understand immigrant students everyday lives in school. In this study, home economics is seen as a fruitful school subject area for understanding these immigrant students lives as they cope with school and home cultures that may be very different from each other. Home economics includes a great deal of knowledge and skills that immigrant students need during their everyday activities outside of school. -- The main aim of the study is to clarify the characteristics of multicultural home economics classroom practices and the multicultural contacts and interaction that take place between the students and the teacher. The study includes four parts. The first part, an ethnographical prestudy, aims to understand the challenges of multicultural schoolwork with the aid of ethnographical fieldwork done in one multicultural school. The second part outlines the theoretical frames of the study and focuses on the sociocultural approach. The third part of the study presents an analysis of videodata collected in a multicultural home economics classroom. The teacher s and students interaction in the home economics classroom is analyzed through the concepts of the sociocultural approach and the cultural-historical activity theory. Firstly, this is done by analyzing the focusedness of the teacher s and the students actions as well as the questions presented and apparent disturbances during classroom interaction. Secondly, the immigrant students everyday experiences and cultural background are examined as they appear during discussions in the home economics lessons. Thirdly, the teacher s tool-use and actions as a human mediator are clarified during interaction in the classroom. The fourth part presents the results, according to which a practice-based approach in the multicultural classroom situation is a prerequisite for the teacher s and the students shared object during classroom interaction. Also, the practice-based approach facilitates students understanding during teaching and learning situations. Practice in this study is understood as collaborative teaching and learning situations that include 1) guided activating learning, 2) establishing connections with students everyday lives and 3) multiple tool-use. Guided activating learning in the classroom is defined as situations that occur and assignments that are done with a knowledgeable adult or peer and include action. The teacher s demonstrations during the practical part of the lessons seemed to be fruitful in the teaching and learning situations in the multicultural classroom. Establishing connections with students everyday lives motivated students to follow the lesson and supported understanding of meaning. Furthermore, if multiple tools (both psychological and material) were used, the students managed better with new and sometimes difficult concepts and different working habits, and accomplished the practical work more smoothly . The teacher s tool-use and role as a mediator of meaning are also highlighted in the data analysis. Hopefully, this study can provide a seedbed for situations in which knowledge produced together, as well as horizontally oriented tool-use, can make school-learned knowledge more relevant to immigrant students everyday lives, and help students to better cope with both classroom work and outside activities. KEY WORDS: home economics education, multicultural education, sociocultural perspective, classroom interaction, videoanalysis
  • Salaspuro, Ville (Helsingin yliopisto, 2006)
    Background: Alcohol consumption and smoking are the main causes of upper digestive tract cancers. These risk factors account for over 75% of all cases in developed countries. Epidemiological studies have shown that alcohol and tobacco interact in a multiplicative way to the cancer risk, but the pathogenetic mechanism behind this is poorly understood. Strong experimental and human genetic linkage data suggest that acetaldehyde is one of the major factors behind the carcinogenic effect. In the digestive tract, acetaldehyde is mainly formed by microbial metabolism of ethanol. Acetaldehyde is also a major constituent of tobacco smoke. Thus, acetaldehyde from both of these sources may have an interacting carcinogenic effect in the human upper digestive tract. Aims: The first aim of this thesis was to investigate acetaldehyde production and exposure in the human mouth resulting from alcohol ingestion and tobacco smoking in vivo. Secondly, specific L-cysteine products were prepared to examine their efficacy in the binding of salivary acetaldehyde in order to reduce the exposure of the upper digestive tract to acetaldehyde. Methods: Acetaldehyde levels in saliva were measured from human volunteers during alcohol metabolism, during tobacco smoking and during the combined use of alcohol and tobacco. The ability of L-cysteine to eliminate acetaldehyde during alcohol metabolism and tobacco smoking was also investigated with specifically developed tablets. Also the acetaldehyde production of Escherichia coli - an important member of the human microbiota - was measured in different conditions prevailing in the digestive tract. Results and conclusions: These studies established that smokers have significantly increased acetaldehyde exposure during ethanol consumption even when not actively smoking. Acetaldehyde exposure was dramatically further increased during active tobacco smoking. Thus, the elevated aerodigestive tract cancer risk observed in smokers and drinkers may be the result of the increased acetaldehyde exposure. Acetaldehyde produced in the oral cavity during ethanol challenge was significantly decreased by a buccal L-cysteine -releasing tablet. Also smoking-derived acetaldehyde could be totally removed by using a tablet containing L-cysteine. In conclusion, this thesis confirms the essential role of acetaldehyde in the pathogenesis of alcohol- and smoking-induced cancers. This thesis presents a novel experimental approach to decrease the local acetaldehyde exposure of the upper digestive tract with L-cysteine, with the eventual goal of reducting the prevalence of upper digestive tract cancers.
  • Ahmed, Imtiaj (2013)
    This thesis explores interaction paradigms for virtual 3D models on large displays. We explored three distant freehand interaction paradigms and for each paradigm we implemented a prototype system. Among these paradigms, it has been found that pointing by hand/eye with selection gesture is the ideal technique to interact with such interfaces. In the pointing technique we reduced the 3D interaction into 2D interaction to explore the 3D contents presented on the large displays. We propose a pinch gesture to select items effortlessly: a gesture of touching index finger with the thumb. Also we found a user-friendly way to present content meta-information of the virtual 3D models and its interactive units during interaction.
  • Palva, J. Matias (Helsingin yliopisto, 2005)
  • Pernu, Tuomas (Helsingin yliopisto, 2013)
    The notion of causal explanation is an essential element of the naturalistic world view. This view is typically interpreted to claim that we are only licensed to postulate entities that make a causal difference , or have causal power . The rest are epiphenomena and hence eliminable from the correct view of reality. The worry that some entities and phenomena that we take for granted mental properties in particular turn out to be epiphenomenal, can be seen as stemming from this sort of naturalistic attitude. This thesis reviews the issue of causal explanation within the context of the naturalistic philosophy of mind. It is argued that there is no single monolithic, unanimously accepted notion of causation that the naturalist should be committed to. Views vary on what this notion amounts to exactly, and fields of science vary with respect to their causal commitments. However, the naturalist can still presume that a scientifically informed philosophical account of causation exists, an account that is fundamentally philosophical, but also sensitive to actual scientific practice and its view of reality. The central issue of the current naturalistic philosophy of mind is the so-called problem of causal exclusion. According to this, the assumption that mental states could have genuine and autonomous effects on the physical world is inconsistent with physical commitments, namely the idea that mental states are necessarily neurally based and the idea that the physical world is causally complete. The causal exclusion argument claims that mental causes must be reduced to physical causes, as there remains no role for independent mental causes. The thesis reviews some central responses to the causal exclusion argument. It is shown that within the context of the interventionist notion of causation, inter-level causation can be ruled out. The causal exclusion argument would thus find support, contrary to what the proponents of the interventionist view typically claim. However, the result is also shown to have the corollary that purely higher-level, mental-to-mental causation is possible. The thesis suggests that this offers a consistent view of mental causation for a naturalist to hold.
  • von Nandelstadh, Pernilla (Helsingin yliopisto, 2010)
    The striated muscle sarcomere is a force generating and transducing unit as well as an important sensor of extracellular cues and a coordinator of cellular signals. The borders of individual sarcomeres are formed by the Z-disks. The Z-disk component myotilin interacts with Z-disk core structural proteins and with regulators of signaling cascades. Missense mutations in the gene encoding myotilin cause dominantly inherited muscle disorders, myotilinopathies, by an unknown mechanism. In this thesis the functions of myotilin were further characterized to clarify the molecular biological basis and the pathogenetic mechanisms of inherited muscle disorders, mainly caused by mutated myotilin. Myotilin has an important function in the assembly and maintenance of the Z-disks probably through its actin-organizing properties. Our results show that the Ig-domains of myotilin are needed for both binding and bundling actin and define the Ig domains as actin-binding modules. The disease-causing mutations appear not to change the interplay between actin and myotilin. Interactions between Z-disk proteins regulate muscle functions and disruption of these interactions results in muscle disorders. Mutations in Z-disk components myotilin, ZASP/Cypher and FATZ-2 (calsarcin-1/myozenin-2) are associated with myopathies. We showed that proteins from the myotilin and FATZ families interact via a novel and unique type of class III PDZ binding motif with the PDZ domains of ZASP and other Enigma family members and that the interactions can be modulated by phosphorylation. The morphological findings typical of myotilinopathies include Z-disk alterations and aggregation of dense filamentous material. The causes and mechanisms of protein aggregation in myotilinopathy patients are unknown, but impaired degradation might explain in part the abnormal protein accumulation. We showed that myotilin is degraded by the calcium-dependent, non-lysosomal cysteine protease calpain and by the proteasome pathway, and that wild type and mutant myotilin differ in their sensitivity to degradation. These studies identify the first functional difference between mutated and wild type myotilin. Furthermore, if degradation of myotilin is disturbed, it accumulates in cells in a manner resembling that seen in myotilinopathy patients. Based on the results, we propose a model where mutant myotilin escapes proteolytic breakdown and forms protein aggregates, leading to disruption of myofibrils and muscular dystrophy. In conclusion, the main results of this study demonstrate that myotilin is a Z-disk structural protein interacting with several Z-disk components. The turnover of myotilin is regulated by calpain and the ubiquitin proteasome system and mutations in myotilin seem to affect the degradation of myotilin, leading to protein accumulations in cells. These findings are important for understanding myotilin-linked muscle diseases and designing treatments for these disorders.
  • Sopanen, Sanna (Helsingin yliopisto, 2009)
    The aim of the studies reported in this thesis was to examine the feeding interactions between calanoid copepods and toxic algae in the Baltic Sea. The central questions in this research concerned the feeding, survival and egg production of copepods exposed to toxic algae. Furthermore, the importance of copepods as vectors in toxin transfer was examined. The haptophyte Prymnesium parvum, which produces extracellular toxins, was the only studied species that directly harmed copepods. Beside this, it had allelopathic effects (cell lysis) on non-toxic Rhodomonas salina. Copepods that were exposed to P. parvum filtrates died or became severely impaired, although filtrates were not haemolytic (indicative of toxicity in this study). Monospecific Prymnesium cell suspensions, in turn, were haemolytic and copepods in these treatments became inactive, although no clear effect on mortality was detected. These results suggest that haemolytic activity may not be a good proxy of the harmful effects of P. parvum. In addition, P. parvum deterred feeding, and low egestion and suppressed egg production were consequently observed in monospecific suspensions of Prymnesium. Similarly, ingestion and faecal pellet production rates were suppressed in high concentration P. parvum filtrates and in mixtures of P. parvum and R. salina. These results indicate that the allelopathic effects of P. parvum on other algal species together with lowered viability as well as suppressed production of copepods may contribute to bloom formation and persistence. Furthermore, the availability of food for planktivorous animals may be affected due to reduced copepod productivity. Nodularin produced by Nodularia spumigena was transferred to Eurytemora affinis via grazing on filaments of small N. spumigena and by direct uptake from the dissolved pool. Copepods also acquired nodularin in fractions where N. spumigena filaments were absent. Thus, the importance of microbial food webs in nodularin transfer should be considered. Copepods were able to remove particulate nodularin from the system, but at the same time a large proportion of the nodularin disappeared. This indicates that copepods may possess effective mechanisms to remove toxins from their tissues. The importance of microorganisms, such as bacteria, in the degradation of cyanobacterial toxins could also be substantial. Our results were the first reports of the accumulation of diarrhetic shellfish toxins (DSTs) produced by Dinophysis spp. in copepods. The PTX2 content in copepods after feeding experiments corresponded to the ingestion of <100 Dinophysis spp. cells. However, no DSTs were recorded from field-collected copepods. Dinophysis spp. was not selected by the copepods and consumption remained low. It seems thus likely that copepods are an unimportant link in the transfer of DSTs in the northern Baltic Sea.
  • Voutilainen, Liina (Helsingin yliopisto, 2013)
    Among rodent-borne pathogens, hantaviruses are one of the most important groups concerning human health and economy. Understanding the interactions between hantaviruses and their reservoir host species is crucial for prediction and prevention of human epidemics. In this thesis, I studied the interactions between Puumala hantavirus (PUUV) and its host, the bank vole (Myodes glareolus). The study was conducted in the boreal zone of Europe, where human incidence of nephropathia epidemica (NE, a mild form of haemorrhagic fever with renal syndrome) caused by PUUV is the highest. Endemic pathogens, such as hantaviruses, have been hypothesized to cause no apparent symptoms or fitness costs to their hosts. However, we found PUUV infection to decrease the over-winter survival of wild bank voles. We also found wild bank voles to shed PUUV via urine, faeces, and saliva throughout their life span without any remarkable decline, in contrast to earlier results from laboratory-reared rodent hosts. For the first time, dynamics of PUUV infection were studied during winter, when the majority of NE cases occur in the boreal zone. We found PUUV-infected bank voles to be most abundant in the winters of increase and peak years of the 3-year density cycle. In bank voles, the prevalence of PUUV infection showed a regular, seasonal fluctuation, which resulted from seasonal population turnover and the positive correlation between age and the likelihood of being PUUV infected. However, despite its regular fluctuation, PUUV prevalence in voles is not a good predictor of human NE risk since the periods of high prevalence coincided with low NE incidence in humans. Aggression has been suggested as the key driver for other hantaviruses in their host species, but the rate of PUUV transmission in bank voles was higher outside the breeding season, when bank voles do not show aggressive behaviour, than during the breeding season. The high rate of transmission outside the breeding season may be attributed to subnivean conditions that promote virus stability, lower immune response during cold conditions, and high host density in fall. We also found evidence for the dilution effect hypothesis, which assumes non-host species to reduce virus transmission between hosts: the prevalence of PUUV was low in bank voles when other small mammals were abundant. Male sex bias in infection is a general phenomenon that has also been observed in several hantavirus-host systems. We found a male bias in PUUV infection only in overwintered, breeding bank voles, whereas a female bias was seen in summer-born breeding animals. In non-breeding animals, no sex differences existed. Therefore, the effects of host sex in hantavirus transmission may be more complex than previously thought. Forest habitats disturbed by intensive forest management were associated with a higher likelihood of PUUV infection in bank voles. This finding could be explained by the poorer quality of these habitats, leading to lower condition and higher susceptibility, and also by more favourable environmental conditions for virus survival outside the host. Despite the higher infection prevalence in voles, the total number of PUUV-infected bank voles was 46-64% lower in young, intensively managed than in undisturbed, old forests. Thus, environmental change per se does not automatically lead to relative success of species that serve as reservoirs for zoonotic pathogens, and thereby, to increased human disease risk. The results of this thesis encourage further studies of host-pathogen interactions in natural conditions, and in different host-hantavirus systems. They also provide a framework for risk models aiming at reduction of human hantavirus infections.
  • Seppänen, Sanna-Kaisa (Helsingin yliopisto, 2007)
    The development of biotechnology techniques in plant breeding and the new commercial applications have raised public and scientific concerns about the safety of genetically modified (GM) crops and trees. To find out the feasibility of these new technologies in the breeding of commercially important Finnish hardwood species and to estimate the ecological risks of the produced transgenic plants, the experiments of this study have been conducted as a part of a larger project focusing on the risk assessment of GM-trees. Transgenic Betula pendula and Populus trees were produced via Agrobacterium mediated transformation. Stilbene synthase (STS) gene from pine (Pinus sylvestris) and chitinase gene from sugar beet (Beta vulgaris) were transferred to (hybrid) aspen and birch, respectively, to improve disease resistance against fungal pathogens. To modify lignin biosynthesis, a 4-coumarate:coenzyme A ligase (4CL) gene fragment in antisense orientation was introduced into two birch clones. In in vitro test, one transgenic aspen line expressing pine STS gene showed increased resistance to decay fungus Phellinus tremulae. In the field, chitinase transgenic birch lines were more susceptible to leaf spot (Pyrenopeziza betulicola) than the non-transgenic control clone while the resistance against birch rust (Melampsoridium betulinum) was improved. No changes in the content or composition of lignin were detected in the 4CL antisense birch lines. In order to evaluate the ecological effects of the produced GM trees on non-target organisms, an in vitro mycorrhiza experiment with Paxillus involutus and a decomposition experiment in the field were performed. The expression of a transgenic chitinase did not disturb the establishment of mycorrhizal symbiosis between birch and P. involutus in vitro. 4CL antisense transformed birch lines showed retarded root growth but were able to form normal ectomycorrhizal associations with the mycorrhizal fungus in vitro. 4CL lines also showed normal litter decomposition. Unexpected growth reductions resulting from the gene transformation were observed in chitinase transgenic and 4CL antisense birch lines. These results indicate that genetic engineering can provide a tool in increasing disease resistance in Finnish tree species. More extensive data with several ectomycorrhizal species is needed to evaluate the consequences of transgene expression on beneficial plant-fungus symbioses. The potential pleiotropic effects of the transgene should also be taken into account when considering the safety of transgenic trees.
  • Alakoskela, Juha-Matti (Helsingin yliopisto, 2006)
  • Alava, Henni (2008)
    The aim of the study is to analyse the interactions of development intervention and conflict in northern Uganda, where over 20 years of armed conflict between the Lord’s Resistance Army rebel movement and the Government of Uganda have caused massive population displacement. The study provides an explanation for the marked increase of development intervention in the region between 2001 and 2006, and an analysis of the effects of this increase. A further aim of the study is to discuss some of the theoretical and methodological challenges in studying development interventions, and to comment on the possibilities for analysing the impacts of intervention on conflict. The research is underpinned by the idea presented by Koponen of intervention as an inseparable element of the modern notion of development. The study can be characterised as methodological developmentalism, that is, the study of how the developmentalist complex works and what it produces in northern Uganda. Long’s notion of social interface is applied as a tool to this analysis. Following Long, it is suggested that development intervention is embedded in complex frameworks and arenas, which must be analysed in order to understand the interactions of intervention and conflict. The transformation of humanitarianism in the post Cold War era is introduced as the normative and conceptual framework into which development intervention in northern Uganda is embedded. The historical, political and international context of conflict in northern Uganda is presented as the arena into which intervention in the region becomes entangled. It is argued that the increase of development intervention in northern Uganda after 2001 can be understood through an analysis of this framework and arena. The study maintains that development intervention and conflict have interacted in northern Uganda, and that such interactions are multifaceted and complex. It is shown that the interactions of intervention and conflict occur both at the level of regional conflict dynamics and donor relations, and on the ground in northern Uganda, in encounters between organisations and individuals involved in intervention processes. The study also shows that such interactions are generally unacknowledged by development and humanitarian actors in the region.
  • Alava, Henni (2008)
    Tutkimuksen tavoitteena on analysoida kehitysintervention ja konfliktin vuorovaikutuksia Pohjois-Ugandassa, missä yli 20 vuotta jatkunut konflikti kapinallisliike Lord’s Resistance Armyn ja Ugandan hallituksen välillä on aiheuttanut laajamittaista maansisäistä pakolaisuutta. Tutkimus tarjoaa selityksen kehitysintervention voimakkaalle lisääntymiselle alueella vuosien 2001 ja 2006 välillä sekä analyysin tämän lisääntymisen vaikutuksista. Tutkimuksen laajempana tavoitteena on keskustella kehitysinterventioiden tutkimiseen liittyvistä teoreettisista ja metodologisista haasteista, sekä kommentoida mahdollisuuksia analysoida kehitysintervention konfliktivaikutuksia. Tutkimus pohjaa Koposen esittämään ajatukseen interventiosta erottamattomana osana modernia kehityksen käsitettä. Tutkimusta voidaan luonnehtia metodologiseksi developmentalismiksi (methodological developmentalism) – tutkimukseksi siitä miten developmentalistinen kompleksi (developmentalist complex) toimii ja mitä se tuottaa Pohjois-Ugandassa. Työkaluna tässä analyysissä sovelletaan Longin sosiaalisen rajapinnan (social interface) käsitettä. Longia mukaillen kehitysintervention katsotaan olevan juurrutettu (embedded) viitekehyksiin ja areenoihin, joiden analysointi on edellytys kehitysintervention ja konfliktin vuorovaikutusten ymmärtämiselle. Kylmän sodan jälkeinen humanitarismin muutos esitellään normatiivisena ja käsitteellisenä viitekehyksenä, johon kehitysinterventio Pohjois-Ugandassa on juurrutettu. Pohjois-Ugandan konfliktin historiallinen, poliittinen ja kansainvälinen konteksti taas esitellään areenana, johon alueelle kohdistuva interventio kietoutuu. Tutkimuksessa esitetään että kehitysintervention lisääntyminen Pohjois-Ugandassa vuoden 2001 jälkeen voidaan ymmärtää tämän viitekehyksen ja areenan analyysin valossa. Tutkimuksen mukaan kehitysinterventio ja konflikti ovat vuorovaikuttaneet Pohjois-Ugandassa, ja tällaiset vuorovaikutukset ovat moni-ilmeisiä ja monimutkaisia. Kehitysintervention ja konfliktin vuorovaikutusten osoitetaan ilmenevän sekä alueellisen konfliktidynamiikan ja avunantajasuhteiden tasolla että interventioprosesseissa mukana olevien järjestöjen ja yksilöiden kohtaamisissa Pohjois-Ugandassa. Tutkimuksessa osoitetaan lisäksi, etteivät kehitys- ja humanitaariset toimijat Pohjois-Ugandassa yleisesti tunnista tämän tyyppisiä vuorovaikutuksia.
  • Kailanto, Sanna (Helsingin yliopisto, 2010)
    It has been hypothesized that abuse of supra-therapeutic doses of anabolic androgenic steroids (AASs) can lead to dependence and function as a gateway to abuse of other drugs. This is supported by behavioral studies on animal models and psychiatric evaluations of human subjects, although their neurochemical effects remain largely unknown. A large body of evidence suggests that the ability of the drugs to induce a strong elevation of extracellular dopamine (DA) levels in the nucleus accumbens (NAc), especially, plays a crucial role in their reinforcing effects. -- This study had four main aims. The first was to explore the effects of nandrolone decanoate on dopaminergic and serotonergic activities in the brains of rats. The second aim was to assess whether or not nandrolone pre-exposure modulates the acute neurochemical and behavioral effects of psychostimulant drugs in experimental animals. The third was to investigate if the AAS-pre-treatment induced changes in brain reward circuitry are reversible. And the fourth main goal was to evaluate the role of androgen and estrogen receptors in the modulation of the dopaminergic and serotonergic effects of acute injections of stimulant drugs by sub-chronic nandrolone treatment. The results showed that nandrolone decanoate at doses, high enough to induce erythropoiesis, significantly increased the levels of DOPAC and 5-HT in the cerebral cortex. Co-administration of AAS and psychostimulant drugs showed that the increase in extracellular DA and 5-HT concentration evoked by amphetamine, MDMA and cocaine in the NAc was attenuated dose-dependently by pretreatment with nandrolone. Nandrolone pre-exposure also attenuated the ability of stimulants to cause increased stereotyped behavior and locomotor activity. Despite the significant decrease in nandrolone concentration in blood, the attenuation of cocaine’s effects remained unchanged after a fairly long period without nandrolone, suggesting that nandrolone effects could be long lasting. Blockade of androgen receptors with flutamide abolished the attenuating effect of nandrolone pretreatment on amphetamine-induced elevation of extracellular DA concentration. --- In conclusion, the results show that AAS-pretreatment is able to inhibit the reward-related neurochemical and behavioral effects of amphetamine, MDMA and cocaine in experimental animals. Furthermore, it seems that these effects could be long lasting and it appears that the ability of nandrolone to modulate reward-related effects of stimulants is dependent on activation of androgen receptors.