Molecular and epidemiological aspects of Streptococcus pyogenes disease in Finland: Severe infections and bacterial, non-necrotizing cellulitis

Streptococcus pyogenes (group A streptococcus) is an important human pathogen, causing a wide array of infections ranging in severity. The majority of S. pyogenes infections are mild upper respiratory tract or skin infections. Severe, invasive infections, such as bacteraemia, are relatively rare, but constitute a major global burden with a high mortality. Certain streptococcal types are associated with a more severe disease and higher mortality. Bacterial, non-necrotizing cellulitis and erysipelas are localised infections of the skin, and although they are usually not life-threatening, they have a tendency to recur and therefore cause substantial morbidity. Despite several efforts aimed at developing an effective and safe vaccine against S. pyogenes infections, no vaccine is yet available. In this study, the epidemiology of invasive S. pyogenes infections in Finland was described over a decade of national, population-based surveillance. Recent trends in incidence, outcome and bacterial types were investigated. The beta-haemolytic streptococci causing cellulitis and erysipelas infections in Finland were studied in a case-control study. Bacterial isolates were characterised using both conventional and molecular typing methods, such as the emm typing, which is the most widely used typing method for beta-haemolytic streptococci. The incidence of invasive S. pyogenes disease has had an increasing trend during the past ten years in Finland, especially from 2006 onwards. Age- and sex-specific differences in the incidence rate were identified, with men having a higher incidence than women, especially among persons aged 45-64 years. In contrast, more infections occurred in women aged 25-34 years than men. Seasonal patterns with occasional peaks during the midsummer and midwinter were observed. Differences in the predisposing factors and underlying conditions of patients may contribute to these distinctions. Case fatality associated with invasive S. pyogenes infections peaked in 2005 (12%) but remained at a reasonably low level (8% overall during 2004-2007) compared to that of other developed countries (mostly exceeding 10%). Changes in the prevalent emm types were associated with the observed increases in incidence and case fatality. In the case-control study, acute bacterial non-necrotizing cellulitis was caused predominantly by Streptococcus dysgalactiae subsp. equisimilis, instead of S. pyogenes. The recurrent nature of cellulitis became evident. This study adds to our understanding of S. pyogenes infections in Finland and provides a basis for comparison to other countries and future trends. emm type surveillance and outcome analyses remain important for detecting such changes in type distribution that might lead to increases in incidence and case fatality. Bacterial characterisation serves as a basis for disease pathogenesis studies and vaccine development.

Atrial remodeling in atrial fibrillation : Epidemiological, clinical and magnetocardiographic aspects

Atrial fibrillation is the most common arrhythmia requiring treatment. This Thesis investigated atrial fibrillation (AF) with a specific emphasis on atrial remodeling which was analysed from epidemiological, clinical and magnetocardiographic (MCG) perspectives. In the first study we evaluated in real-life clinical practice a population-based cohort of AF patients referred for their first elective cardioversion (CV). 183 consecutive patients were included of whom in 153 (84%) sinus rhythm (SR) was restored. Only 39 (25%) of those maintained SR for one year. Shorter duration of AF and the use of sotalol were the only characteristics associated with better restoration and maintenance of SR. During the one-year follow-up 40% of the patients ended up in permanent AF. Female gender and older age were associated with the acceptance of permanent AF. The LIFE-trial was a prospective, randomised, double-blinded study that evaluated losartan and atenolol in patients with hypertension and left ventricular hypertrophy (LVH). Of the 8,851 patients with SR at baseline and without a history of AF 371 patients developed new-onset AF during the study. Patients with new-onset AF had an increased risk of cardiac events, stroke, and increased rate of hospitalisation for heart failure. Younger age, female gender, lower systolic blood pressure, lesser LVH in ECG and randomisation to losartan therapy were independently associated with lower frequency of new-onset AF. The impact of AF on morbidity and mortality was evaluated in a post-hoc analysis of the OPTIMAAL trial that compared losartan with captopril in patients with acute myocardial infarction (AMI) and evidence of LV dysfunction. Of the 5,477 randomised patients 655 had AF at baseline, and 345 patients developed new AF during the follow-up period, median 3.0 years. Older patients and patients with signs of more serious heart disease had and developed AF more often. Patients with AF at baseline had an increased risk of mortality (hazard ratio (HR) of 1.32) and stroke (HR 1.77). New-onset AF was associated with increased mortality (HR 1.82) and stroke (HR of 2.29). In the fourth study we assessed the reproducibility of our MCG method. This method was used in the fifth study where 26 patients with persistent AF had immediately after the CV longer P-wave duration and higher energy of the last portion of atrial signal (RMS40) in MCG, increased P-wave dispersion in SAECG and decreased pump function of the atria as well as enlarged atrial diameter in echocardiography compared to age- and disease-matched controls. After one month in SR, P-wave duration in MCG still remained longer and left atrial (LA) diameter greater compared to the controls, while the other measurements had returned to the same level as in the control group. In conclusion is not a rare condition in either general population or patients with hypertension or AMI, and it is associated with increased risk of morbidity and mortality. Therefore, atrial remodeling that increases the likelihood of AF and also seems to be relatively stable has to be identified and prevented. MCG was found to be an encouraging new method to study electrical atrial remodeling and reverse remodeling. RAAS-suppressing medications appear to be the most promising method to prevent atrial remodeling and AF.

Very Low Birth Weight Infants as Young Adults : Focus on aspects of cognition, behavior and sleep

Major advances in the treatment of preterm infants have occurred during the last three decades. Survival rates have increased, and the first generations of preterm infants born at very low birth weight (VLBW; less than 1500 g) who profited from modern neonatal intensive care are now in young adulthood. The literature shows that VLBW children achieve on average lower scores on cognitive tests, even after exclusion of individuals with obvious neurosensory deficits. Evidence also exists for an increased risk in VLBW children for various neuropsychiatric disorders such as attention-deficit hyperactivity disorder (ADHD) and related behavioral symptoms. Up till now, studies extending into adulthood are sparse, and it remains to be seen whether these problems persist into adulthood. The aim of this thesis was to study ADHD-related symptoms and cognitive and executive functioning in young adults born at VLBW. In addition, we aimed to study sleep disturbances, known to adversely affect both cognition and attention. We hypothesized that preterm birth at VLBW interferes with early brain development in a way that alters the neuropsychological phenotype; this may manifest itself as ADHD symptoms and impaired cognitive abilities in young adulthood. In this cohort study from a geographically defined region, we studied 166 VLBW adults and 172 term-born controls born from 1978 through 1985. At ages 18 to 27 years, the study participants took part in a clinic study during which their physical and psychological health was assessed in detail. Three years later, 213 of these individuals participated in a follow-up. The current study is part of a larger research project (The Helsinki Study of Very Low Birth Weight Adults), and the measurements of interest for this particular study include the following: 1) The Adult Problem Questionnaire (APQ), a self-rating scale of ADHD-related symptoms in adults; 2) A computerized cognitive test battery designed for population studies (CogState®) which measures core cognitive abilities such as reaction time, working memory, and visual learning; 3) Sleep assessment by actigraphy, the Basic Nordic Sleep Questionnaire, and the Morningness-Eveningness Questionnaire. Actigraphs are wrist-worn accelerometers that separate sleep from wakefulness by registering body movements. Contrary to expectations, VLBW adults as a group reported no more ADHD-related behavioral symptoms than did controls. Further subdivision of the VLBW group into SGA (small for gestational age) and AGA (appropriate for gestational age) subgroups, however, revealed more symptoms on ADHD subscales pertaining to executive dysfunction and emotional instability among those born SGA. Thus, it seems that intrauterine growth retardation (for which SGA served as a proxy) is a more essential predictor for self-perceived ADHD symptoms in adulthood than is VLBW birth as such. In line with observations from other cohorts, the VLBW adults reported less risk-taking behavior in terms of substance use (alcohol, smoking, and recreational drugs), a finding reassuring for the VLBW individuals and their families. On the cognitive test, VLBW adults free from neurosensory deficits had longer reaction times than did term-born peers on all tasks included in the test battery, and lower accuracy on the learning task, with no discernible effect of SGA status over and above the effect of VLBW. Altogether, on a group level, even high-functioning VLBW adults show subtle deficits in psychomotor processing speed, visual working memory, and learning abilities. The sleep studies provided no evidence for differences in sleep quality or duration between the two groups. The VLBW adults were, however, at more than two-fold higher risk for sleep-disordered breathing (in terms of chronic snoring). Given the link between sleep-disordered breathing and health sequelae, these results suggest that VLBW individuals may benefit from an increased awareness among clinicians of this potential problem area. An unexpected finding from the sleep studies was the suggestion of an advanced sleep phase: The VLBW adults went to bed earlier according to the actigraphy registrations and also reported earlier wake-up times on the questionnaire. In further study of this issue in conjunction with the follow-up three years later, the VLBW group reported higher levels of morningness propensity, further corroborating the preliminary findings of an advanced sleep phase. Although the clinical implications are not entirely clear, the issue may be worth further study, since circadian rhythms are closely related to health and well-being. In sum, we believe that increased understanding of long-term outcomes after VLBW, and identification of areas and subgroups that are particularly vulnerable, will allow earlier recognition of potential problems and ultimately lead to improved prevention strategies.

The Saintly Madman : A Study of the Scholarly Reception History of Buile Shuibhne

This study examines the scholarly reception history of an early Irish text, Buile Shuibhne (The Frenzy of Suibhne), by focusing on the various theoretical and methodological presuppositions which have determined the scholars’ understanding of the text’s religious allegorical significance in the course of the 20th century. The reception-oriented inquiry takes the intersubjective aspect of literary interpretation as the basis for accentuating the importance of communally shared presumptions and reading strategies in the explication of interpretive variety. The materials of the study have been divided into four frameworks of interpretation: historical, pre-Christian, Christian and anthropological. This heuristic division does not denote mutually exclusive paradigms, but rather refers to perceived similarities within each group regarding the questions posed, and the evidence adduced, in textual analysis. The historical framework concentrates on the issues of the origins of the tale and the possible historicity of its main protagonist. The pre-Christian framework covers the theories of the shamanic, Indo-European and Celtic elements in the text, whereas the Christian framework includes readings emphasising the biblical, monastic and ascetic aspects of the tale. The anthropological framework in turn focuses on the parallels drawn between the narrative and the universal structure of the rites of passage. In addition to the examination of these four frameworks, the study also links the question of methodology with wider issues of authorship and textual integrity, and critically reconsiders the manner in which J.G. O'Keeffe's 1913 edition of the text has been reified in previous scholarship as a representation of a 12th century authorial original. The overall objective of the present case-study is to relate theoretical conceptions of literary theory, comparative religion and historiography to the study of early Irish narrative material by considering the communal and institutional dimension of meaning-making, and the implications of comparative methodology for historical research. In this aim, the prevailing methodological presuppositions informing the scholarly discourse on Buile Shuibhne are set against the wider context of Celtic Studies scholarship, in order to draw attention to the need to critically reflect upon the operations of knowledge production in future research.

The Homeless Etiquette : Social Interaction and Behavior Among the Homeless in Taito Ward, Tokyo

The thesis focuses on the social interaction and behavior of the homeless living in Tokyo's Taito Ward. The study is based on the author's own ethnographic field research carried out in the autumn 2003. The chosen methodologies were based on the methodology called "participant observation", and they were used depending on the context. The ethnographic field research was carried out from the mid-August to the beginning of the October in 2003. The most important targets of the research were three separate loosely knit groups placed in certain parts of Taito Ward. One of these groups was based in proximity to the Ueno train station, one group gathered every morning around a homeless support organization called San'yûkai, and one was based in Tamahime Park located in the old San'ya area of Tokyo. The analysis is based on the aspects of Takie Sugiyama Lebra's theory of "social relativism". Lebra's theory consists of the following, arguably universal aspects: belongingness, empathy, dependence, place in the society, and reciprocity. In addition, all the interaction and behavior is tied to the context and the situation. According to Lebra, ritual and intimate situations produce similar action, which is socially relative. Of these, the norms of the ritual behavior are more regulated, while the intimate bahavior is less spontaneous. On the contrary, an anomic situation produces anomic behavior, which is not socially relative. Lebra's theory is critically reviewed by the author of the thesis, and the author has attempted to modify the theory to make it more adaptable to the present-day society and to the analysis. Erving Goffman's views of the social interaction and Anthony Giddens' theories about the social structures have been used as complementary thoretical basis. The aim of the thesis is to clarify, how and why the interaction and the behavior of some homeless individuals in some situations follow the aspects of Lebra's "social relativism", and on the other hand, why in some situations they do not. In the latter cases the answers can be sought from regional and individual differences, or from the inaptness of the theory to analyze the presented situation. Here, a significant factor is the major finding of the field study: the so called "homeless etiquette", which is an abstract set of norms and values that influences the social interaction and behavior of the homeless, and with which many homeless individuals presented in the study complied. The fundamental goal of the thesis is to reach profound understanding about the daily life of the homeless, whose lives were studied. The author argues that this kind of profound understanding is necessary in looking for sustainable solutions in the areas of social and housing policy to improve the position of the homeless and the qualitative functioning of the society.

Proektirovanie perevodčeskih slovarej special'noj leksiki

The methodology of designing normative terminological products has been described in several guides and international standards. However, this methodology is not always applicable to designing translation-oriented terminological products which differ greatly from normative ones in terms of volume, function, and primary target group. This dissertation has three main goals. The first is to revise and enrich the stock of concepts and terms required in the process of designing an LSP dictionary for translators. The second is to detect, classify, and describe the factors which determine the characteristics of an LSP dictionary for translators and affect the process of its compilation. The third goal is to provide recommendations on different aspects of dictionary design. The study is based on an analysis of dictionaries, dictionary reviews, literature on translation-oriented lexicography, material from several dictionary projects, and the results of questionnaires. Thorough analysis of the concept of a dictionary helped us to compile a list of designable characteristics of a dictionary. These characteristics include target group, function, links to other resources, data carrier, list of lemmata, information about the lemmata, composition of other parts of the dictionary, compression of the data, structure of the data, and access structure. The factors which determine the characteristics of a dictionary have been divided into those derived from the needs of the intended users and those reflecting the restrictions of the real world (e.g. characteristics of the data carrier and organizational factors) and attitudes (e.g. traditions and scientific paradigms). The designer of a dictionary is recommended to take the intended users' needs as the starting point and aim at finding the best compromise between the conflicting factors. When designing an LSP dictionary, much depends on the level of knowledge of the intended users about the domain in question as well as their general linguistic competence, LSP competence, and lexicographic competence. This dissertation discusses the needs of LSP translators and the role of the dictionary in the process of translation of an LSP text. It also emphasizes the importance of planning lexicographic products and activities, and addresses many practical aspects of dictionary design.

Turning the Kaleidoscope - (E)FL Educational Experience and Inquiry as Auto/biography

This book is a study on learning, teaching/counselling, and research on the two. My quest has been to find a pedagogically-motivated way of researching learning and teaching interaction, and in particular counselling, in an autonomous language-learning environment. I have tried to develop a method that would make room for lived experience, meaning-making and narrating, because in my view these all characterise learning encounters between language learners and counsellors, and learners and their peers. Lived experience as a source of meaning, telling and co-telling becomes especially significant when we try to listen to the diverse personal and academic voices of the past as expressed in autobiographical narratives. I have aimed at researching various ALMS dialogues (Autonomous Learning Modules, University of Helsinki Language Centre English course and programme), and autobiographical narratives within them, in a way that shows respect for the participants, and that is relevant, reflective and, most importantly, self-reflexive. My interest has been in autobiographical telling in (E)FL [(English as a) foreign language], both in students first-person written texts on their language- learning histories and in the sharing of stories between learners and a counsellor. I have turned to narrative inquiry in my quest and have written the thesis as an experiential narrative. In particular, I have studied learners and counsellors in one and the same story, as characters in one narrative, in an attempt to avoid the impression that I am telling yet another separate, anecdotal story, retrospectively. Through narrative, I have shed light on the subjective dimensions of language learning and experience, and have come closer to understanding the emotional aspects of learning encounters. I have questioned and rejected a distanced and objective approach to describing learning and teaching/counselling. I have argued for a holistic and experiential approach to (E)FL encounters in which there is a need to see emotion and cognition as intertwined, and thus to appreciate learners and counsellors emotionally-charged experiences as integral to their identities. I have also argued for a way of describing such encounters as they are situated in history, time, autobiography, and the learning context. I have turned my gaze on various constellations of lived experience: the data was collected on various occasions and in various settings during one course and consists of videotaped group sessions, individual counselling sessions between students and their group counsellor, biographic narrative interviews with myself, open-ended personally-inspired reflection texts written by the students about their language-learning histories, and student logs and diaries. I do not consider data collection an unproblematic occasion, or innocent practice, and I defend the integrity of the research process. Research writing cannot be separated from narrative field work and analysing and interpreting the data. The foci in my work have turned to be the following: 1) describing ALMS encounters and specifying their narrative aspects; 2) reconceptualising learner and teacher autonomy in ALMS and in (E)FL; 2) developing (E)FL methodologically through a teacher-researcher s identity work; 4) research writing as a dialogical narrative process, and the thesis as an experiential narrative. Identity and writing as inquiry, and the deeply narrative and autobiographical nature of the (E)FL teaching/counselling/researching have come to the fore in this research. Research writing as a relational activity and its implications for situated ways of knowing and knowledge turned out to be important foci. I have also focussed on the context-bound and local teacher knowledge and ways of knowing about being a teacher, and I have argued for personal ways of knowing about, and learning and studying foreign languages. I discuss research as auto/biography: as a practising counsellor I use my own life and (E)FL experience to understand and interpret the stories of the research participants even though I was not involved in their course work. The supposedly static binaries of learner/teacher, and also learner autonomy/teacher autonomy, are thus brought into the discussion. I have highlighted the infinite variability and ever-changing nature of learning and teaching English, but the book is also of relevance to foreign language education in general.

Virtual versus classroom language teaching : A comparative study of the learning outcomes and student responses between two English reading comprehension groups

A 26-hour English reading comprehension course was taught to two groups of second year Finnish Pharmacy students: a virtual group (33 students) and a teacher-taught group (25 students). The aims of the teaching experiment were to find out: 1.What has to be taken into account when teaching English reading comprehension to students of pharmacy via the Internet and using TopClass? 2. How will the learning outcomes of the virtual group and the control group differ? 3. How will the students and the Department of Pharmacy respond to the different and new method, i.e. the virtual teaching method? 4. Will it be possible to test English reading comprehension learning material using the groupware tool TopClass? The virtual exercises were written within the Internet authoring environment, TopClass. The virtual group was given the reading material and grammar booklet on paper, but they did the reading comprehension tasks (written by the teacher), autonomously via the Internet. The control group was taught by the same teacher in 12 2-hour sessions, while the virtual group could work independently within the given six weeks. Both groups studied the same material: ten pharmaceutical articles with reading comprehension tasks as well as grammar and vocabulary exercises. Both groups took the same final test. Students in both groups were asked to evaluate the course using a 1 to 5 rating scale and they were also asked to assess their respective courses verbally. A detailed analysis of the different aspects of the student evaluation is given. Conclusions: 1.The virtual students learned pharmaceutical English relatively well but not significantly better than the classroom students 2. The overall student satisfaction in the virtual pharmacy English reading comprehension group was found to be higher than that in the teacher-taught control group. 3. Virtual learning is easier for linguistically more able students; less able students need more time with the teacher. 4. The sample in this study is rather small, but it is a pioneering study. 5. The Department of Pharmacy in the University of Helsinki wishes to incorporate virtual English reading comprehension teaching in its curriculum. 6. The sophisticated and versatile TopClass system is relatively easy for a traditional teacher and quite easy for the students to learn. It can be used e.g. for automatic checking of routine answers and document transfer, which both lighten the workloads of both parties. It is especially convenient for teaching reading comprehension. Key words: English reading comprehension, teacher-taught class, virtual class, attitudes of students, learning outcomes

Aavan meren täällä puolen : Arkkityyppiset piirteet ja amerikkalaisvaikutteet suosituimmissa suomalaisissa molli-iskelmissä

What are the musical features that turn a song into a hit? The aim of this research is to explore the musical features of hit tunes by studying the 224 most popular Finnish evergreens from the 1930s to the 1990s. It is remarkable, that 80-90% of Finnish oldies are in a minor key, though parallel major keys have also been widely employed within single pieces through, for example, modulations. Furthermore, melodies are usually diatonic, staying mostly in the same key. Consequently, chromatically altered tones in the melody and short modulations in the bridge sections become more prominent. I have concentrated in particular on the melodic lines in order to find the most typical melodic formulas from the data. These analyzed melodic formulas play an important role, because they serve as leading phrases and punchlines in songs. Analysis has revealed three major melodic formulas, which most often appear in the melodic lines of hit tunes. All of these formulas share common thematic ground, because they originate from the triadic tonic chord. Because the tonic chord is the most conventional opening chord in the verse parts, it is logical that these formulas occur most often in verses. The strong dominance of these formulas is very much a result of the rhythmic flexibility they possess; for instance, they can be found in every musical style from waltz to foxtrot. Alongside the major formulas lies a miscellaneous group of other tonic-related melodic formulas. One group of melodic formulas consists of melodic quotations. These quotations appear in a different musical context, for instance in a harmonically altered form, and are therefore often difficult to recognize as such. Yet despite the contextual manipulation, the distinctive character of the cited melody usually remains the same. Composers have also made use of certain popular chord-progressions in order to create new but familiar-sounding melodies. The most important individual progression in this case is what is known as a "circle of fifths" and its shortened, prolonged and altered versions. Because that progression is harmonically strong, it is also a contrastive tool used especially in chorus parts and middle sections (AABA). I have also paid attention to ragtime and jazz influences, which can be found in harmony parts and certain melody notes, which extend, suspend or alter the accompaning chords. Other influences from jazz and ragtime in the Finnish evergreen are evident in the use of typical Tin Pan Alley popular song forms. The most important is the AABA form, which dominates over the data along with the verse/chorus-type popular song form. To briefly illustrate the main results, the basic concept of the hit tune can be traced back to Tin Pan Alley songs, whereas the major stylistic aspects, such as minor keys and musical styles, bear influences from Russian, Western European, and Finnish traditions.

Changes in Beer Labels and their Meaning : A Holistic Approach to the Semiosic Process

The purpose of this study is to find a framework for a holistic approach to, and form a conceptual toolbox for, investigating changes in signs and in their interpretation. Charles S. Peirce s theory of signs in a communicative perspective is taken as a basis for the framework. The concern directing the study is the problem of a missing framework in analysing signs of visual artefacts from a holistic perspective as well as that of the missing conceptual tools. To discover the possibility of such a holistic approach to semiosic processes and to form a conceptual toolbox the following issues are discussed: i) how the many Objects with two aspects involved in Peirce s definition of sign-action, promote multiple semiosis arising from the same sign by the same Interpretant depending on the domination of the Objects; ii) in which way can the relation of the individual and society or group be made more apparent in the construction of the self since this construction is intertwined with the process of meaning-creation and interpretation; iii) how to account for the fundamental role of emotions in semiosis, and the relation of emotions with the often neglected topic of embodiment; iv) how to take into account the dynamic, mediating and processual nature of sign-action in analysing and understanding the changes in signs and in the interpretation of signs. An interdisciplinary approach is chosen for this dissertation. Concepts that developed within social psychology, developmental psychology, neurosciences and semiotics, are discussed. The common aspect of the approaches is that they in one way or another concentrate on mediation provided by signs in explaining human activity and cognition. The holistic approach and conceptual toolbox found are employed in a case study. This consists of an analysis of beer brands including a comparison of brands from two different cultures. It becomes clear that different theories and approaches have mutual affinities and do complement each other. In addition, the affinities in different disciplines somewhat provide credence to the various views. From the combined approach described, it becomes apparent that by the semiosic process, the emerging semiotic self intertwined with the Umwelt, including emotions, can be described. Seeing the interpretation and meaning-making through semiosis allows for the analysis of groups, taking into account the embodied and emotional component. It is concluded that emotions have a crucial role in all human activity, including so-called reflective thinking, and that emotions and embodiment should be consciously taken into account in analysing signs, the interpretation, and in changes of signs and interpretations from both the social and individual level. The analysis of the beer labels expresses well the intertwined nature of the relationship between signs, individual consumers and society. Many direct influences from society on the label design are found, and also some indirect attitude changes that become apparent from magazines, company reports, etc. In addition, the analysis brings up the issues of the unifying tendency of the visual artefacts of different cultures, but also demonstrates that the visual artefacts are able to hold the local signs and meanings, and sometimes are able to represent the local meanings although the signs have changed in the unifying process.

Assessing organizational culture in complex sociotechnical systems : Methodological evidence from studies in nuclear power plant maintenance organizations

Failures in industrial organizations dealing with hazardous technologies can have widespread consequences for the safety of the workers and the general population. Psychology can have a major role in contributing to the safe and reliable operation of these technologies. Most current models of safety management in complex sociotechnical systems such as nuclear power plant maintenance are either non-contextual or based on an overly-rational image of an organization. Thus, they fail to grasp either the actual requirements of the work or the socially-constructed nature of the work in question. The general aim of the present study is to develop and test a methodology for contextual assessment of organizational culture in complex sociotechnical systems. This is done by demonstrating the findings that the application of the emerging methodology produces in the domain of maintenance of a nuclear power plant (NPP). The concepts of organizational culture and organizational core task (OCT) are operationalized and tested in the case studies. We argue that when the complexity of the work, technology and social environment is increased, the significance of the most implicit features of organizational culture as a means of coordinating the work and achieving safety and effectiveness of the activities also increases. For this reason a cultural perspective could provide additional insight into the problem of safety management. The present study aims to determine; (1) the elements of the organizational culture in complex sociotechnical systems; (2) the demands the maintenance task sets for the organizational culture; (3) how the current organizational culture at the case organizations supports the perception and fulfilment of the demands of the maintenance work; (4) the similarities and differences between the maintenance cultures at the case organizations, and (5) the necessary assessment of the organizational culture in complex sociotechnical systems. Three in-depth case studies were carried out at the maintenance units of three Nordic NPPs. The case studies employed an iterative and multimethod research strategy. The following methods were used: interviews, CULTURE-survey, seminars, document analysis and group work. Both cultural analysis and task modelling were carried out. The results indicate that organizational culture in complex sociotechnical systems can be characterised according to three qualitatively different elements: structure, internal integration and conceptions. All three of these elements of culture as well as their interrelations have to be considered in organizational assessments or important aspects of the organizational dynamics will be overlooked. On the basis of OCT modelling, the maintenance core task was defined as balancing between three critical demands: anticipating the condition of the plant and conducting preventive maintenance accordingly, reacting to unexpected technical faults and monitoring and reflecting on the effects of maintenance actions and the condition of the plant. The results indicate that safety was highly valued at all three plants, and in that sense they all had strong safety cultures. In other respects the cultural features were quite different, and thus the culturally-accepted means of maintaining high safety also differed. The handicraft nature of maintenance work was emphasised as a source of identity at the NPPs. Overall, the importance of safety was taken for granted, but the cultural norms concerning the appropriate means to guarantee it were little reflected. A sense of control, personal responsibility and organizational changes emerged as challenging issues at all the plants. The study shows that in complex sociotechnical systems it is both necessary and possible to analyse the safety and effectiveness of the organizational culture. Safety in complex sociotechnical systems cannot be understood or managed without understanding the demands of the organizational core task and managing the dynamics between the three elements of the organizational culture.