Intergenerational Transfer of Sabbath Observance : How is Religious Tradition Transferred to Children among Finnish Seventh-day Adventists?

This study examined religious home education in educational, psychological, and sociological context. Growing up within a religious denomination is a process of learning the rules, norms, opinions, and attitudes, which serve to make the individual an active member of the group. It is a process of transferring the cultural inheritance between generations. Sabbathkeeping can be regarded as a strong indicator of the Seventh-day Adventist value system, which is also why I have concentrated on this specific issue in my study. The purpose of the study was to find out, how the Sabbath is transferred from parents to children among Finnish Adventists. It was also examined how parents could make the day of rest positively exceptional for children, and how the parental authoritativeness affects the process of transference. According to Bull & Lockhart s (1989) theory, the amount of Adventist generations in family history influences the transfer of religious tradition. This study aimed to find out whether or not this theory would apply to the present-day Finland. The nature of religious development among Adventist young people was also one of the interests of the research. The methods used in the study were in-depth interviews (n = 10) and a survey (n = 106). The majority of the interviewees was young adults (age 15-30) grown up in Adventist families. The interviews were taped and transcribed for the study, and survey answers were analysed with SPSS-data analysis program. The amount of survey questionnaires evaluated was 106, whole population of 15-30 year-old Finnish Adventists being about one thousand. Democratic relationship between parents and children, parents' example, encouragement to own thinking, and positive experiences of Sabbath and the whole religion, including the social dimension of the Adventism, seem to be some of the most significant factors in transference of religious tradition. Both too severe and too permissive education were considered to lead to similar results: unsuccessful transfer of values, or even rebellion and adopting a totally opposite way of life than that of the parents. In this study the amount of Adventist generations in family history does not correlate significantly with the end results of value transference. Keywords: Sabbath, intergenerational, value transference, religious home education Avainsanat: sapatti, arvojen siirtyminen vanhemmilta lapsille, uskonnollinen kotikasvatus

Prevention of type 2 diabetes with lifestyle intervention - emphasis on dietary composition and identification of high-risk individuals

Type 2 diabetes is an increasing, serious, and costly public health problem. The increase in the prevalence of the disease can mainly be attributed to changing lifestyles leading to physical inactivity, overweight, and obesity. These lifestyle-related risk factors offer also a possibility for preventive interventions. Until recently, proper evidence regarding the prevention of type 2 diabetes has been virtually missing. To be cost-effective, intensive interventions to prevent type 2 diabetes should be directed to people at an increased risk of the disease. The aim of this series of studies was to investigate whether type 2 diabetes can be prevented by lifestyle intervention in high-risk individuals, and to develop a practical method to identify individuals who are at high risk of type 2 diabetes and would benefit from such an intervention. To study the effect of lifestyle intervention on diabetes risk, we recruited 522 volunteer, middle-aged (aged 40 - 64 at baseline), overweight (body mass index > 25 kg/m2) men (n = 172) and women (n = 350) with impaired glucose tolerance to the Diabetes Prevention Study (DPS). The participants were randomly allocated either to the intensive lifestyle intervention group or the control group. The control group received general dietary and exercise advice at baseline, and had annual physician's examination. The participants in the intervention group received, in addition, individualised dietary counselling by a nutritionist. They were also offered circuit-type resistance training sessions and were advised to increase overall physical activity. The intervention goals were to reduce body weight (5% or more reduction from baseline weight), limit dietary fat (< 30% of total energy consumed) and saturated fat (< 10% of total energy consumed), and to increase dietary fibre intake (15 g / 1000 kcal or more) and physical activity (≥ 30 minutes/day). Diabetes status was assessed annually by a repeated 75 g oral glucose tolerance testing. First analysis on end-points was completed after a mean follow-up of 3.2 years, and the intervention phase was terminated after a mean duration of 3.9 years. After that, the study participants continued to visit the study clinics for the annual examinations, for a mean of 3 years. The intervention group showed significantly greater improvement in each intervention goal. After 1 and 3 years, mean weight reductions were 4.5 and 3.5 kg in the intervention group and 1.0 kg and 0.9 kg in the control group. Cardiovascular risk factors improved more in the intervention group. After a mean follow-up of 3.2 years, the risk of diabetes was reduced by 58% in the intervention group compared with the control group. The reduction in the incidence of diabetes was directly associated with achieved lifestyle goals. Furthermore, those who consumed moderate-fat, high-fibre diet achieved the largest weight reduction and, even after adjustment for weight reduction, the lowest diabetes risk during the intervention period. After discontinuation of the counselling, the differences in lifestyle variables between the groups still remained favourable for the intervention group. During the post-intervention follow-up period of 3 years, the risk of diabetes was still 36% lower among the former intervention group participants, compared with the former control group participants. To develop a simple screening tool to identify individuals who are at high risk of type 2 diabetes, follow-up data of two population-based cohorts of 35-64 year old men and women was used. The National FINRISK Study 1987 cohort (model development data) included 4435 subjects, with 182 new drug-treated cases of diabetes identified during ten years, and the FINRISK Study 1992 cohort (model validation data) included 4615 subjects, with 67 new cases of drug-treated diabetes during five years, ascertained using the Social Insurance Institution's Drug register. Baseline age, body mass index, waist circumference, history of antihypertensive drug treatment and high blood glucose, physical activity and daily consumption of fruits, berries or vegetables were selected into the risk score as categorical variables. In the 1987 cohort the optimal cut-off point of the risk score identified 78% of those who got diabetes during the follow-up (= sensitivity of the test) and 77% of those who remained free of diabetes (= specificity of the test). In the 1992 cohort the risk score performed equally well. The final Finnish Diabetes Risk Score (FINDRISC) form includes, in addition to the predictors of the model, a question about family history of diabetes and the age category of over 64 years. When applied to the DPS population, the baseline FINDRISC value was associated with diabetes risk among the control group participants only, indicating that the intensive lifestyle intervention given to the intervention group participants abolished the diabetes risk associated with baseline risk factors. In conclusion, the intensive lifestyle intervention produced long-term beneficial changes in diet, physical activity, body weight, and cardiovascular risk factors, and reduced diabetes risk. Furthermore, the effects of the intervention were sustained after the intervention was discontinued. The FINDRISC proved to be a simple, fast, inexpensive, non-invasive, and reliable tool to identify individuals at high risk of type 2 diabetes. The use of FINDRISC to identify high-risk subjects, followed by lifestyle intervention, provides a feasible scheme in preventing type 2 diabetes, which could be implemented in the primary health care system.

Markers of systemic inflammation in diagnostics and in prediction of outcome of community-acquired infection

Sepsis is associated with a systemic inflammatory response. It is characterised by an early proinflammatory response and followed by a state of immunosuppression. In order to improve the outcome of patients with infection and sepsis, novel therapies that influence the systemic inflammatory response are being developed and utilised. Thus, an accurate and early diagnosis of infection and evaluation of immune state are crucial. In this thesis, various markers of systemic inflammation were studied with respect to enhancing the diagnostics of infection and of predicting outcome in patients with suspected community-acquired infection. A total of 1092 acutely ill patients admitted to a university hospital medical emergency department were evaluated, and 531 patients with a suspicion of community-acquired infection were included for the analysis. Markers of systemic inflammation were determined from a blood sample obtained simultaneously with a blood culture sample on admission to hospital. Levels of phagocyte CD11b/CD18 and CD14 expression were measured by whole blood flow cytometry. Concentrations of soluble CD14, interleukin (IL)-8, and soluble IL-2 receptor α (sIL-2Rα) were determined by ELISA, those of sIL-2R, IL-6, and IL-8 by a chemiluminescent immunoassay, that of procalcitonin by immunoluminometric assay, and that of C-reactive protein by immunoturbidimetric assay. Clinical data were collected retrospectively from the medical records. No marker of systemic inflammation, neither CRP, PCT, IL-6, IL-8, nor sIL-2R predicted bacteraemia better than did the clinical signs of infection, i.e., the presence of infectious focus or fever or both. IL-6 and PCT had the highest positive likelihood ratios to identify patients with hidden community-acquired infection. However, the use of a single marker failed to detect all patients with infection. A combination of markers including a fast-responding reactant (CD11b expression), a later-peaking reactant (CRP), and a reactant originating from inflamed tissues (IL-8) detected all patients with infection. The majority of patients (86.5%) with possible but not verified infection showed levels exceeding at least one cut-off limit of combination, supporting the view that infection was the cause of their acute illness. The 28-day mortality of patients with community-acquired infection was low (3.4%). On admission to hospital, the low expression of cell-associated lipopolysaccharide receptor CD14 (mCD14) was predictive for 28-day mortality. In the patients with severe forms of community-acquired infection, namely pneumonia and sepsis, high levels of soluble CD14 alone did not predict mortality, but a high sCD14 level measured simultaneously with a low mCD14 raised the possibility of poor prognosis. In conclusion, to further enhance the diagnostics of hidden community-acquired infection, a combination of inflammatory markers is useful; 28-day mortality is associated with low levels of mCD14 expression at an early phase of the disease.

Noncommutativity and Some of Its Present-Day Developments

This masters thesis explores some of the most recent developments in noncommutative quantum field theory. This old theme, first suggested by Heisenberg in the late 1940s, has had a renaissance during the last decade due to the firmly held belief that space-time becomes noncommutative at small distances and also due to the discovery that string theory in a background field gives rise to noncommutative field theory as an effective low energy limit. This has led to interesting attempts to create a noncommutative standard model, a noncommutative minimal supersymmetric standard model, noncommutative gravity theories etc. This thesis reviews themes and problems like those of UV/IR mixing, charge quantization, how to deal with the non-commutative symmetries, how to solve the Seiberg-Witten map, its connection to fluid mechanics and the problem of constructing general coordinate transformations to obtain a theory of noncommutative gravity. An emphasis has been put on presenting both the group theoretical results and the string theoretical ones, so that a comparison of the two can be made.

Mechanisms of KCC2 upregulation during development

Gamma-aminobutyric acid (GABA) acting through ionotropic GABAA receptors plays a crucial role in the activity of the central nervous system (CNS). It triggers Ca2+ rise providing trophic support in developing neurons and conducts fast inhibitory function in mature neuronal networks. There is a developmental change in the GABAA reversal potential towards more negative levels during the first two postnatal weeks in rodent hippocampus. This change provides the basis for mature GABAergic activity and is attributable to the developmental expression of the neuron-specific potassium chloride cotransporter 2 (KCC2). In this work we have studied the mechanisms responsible for the control of KCC2 developmental expression. As a model system we used hippocampal dissociated cultures plated from embryonic day (E) 17 mice embryos before the onset of KCC2 expression. We showed that KCC2 was significantly up-regulated during the first two weeks of culture development. Interestingly, the level of KCC2 upregulation was not altered by chronic pharmacological blockage of action potentials as well as GABAergic and glutamatergic synaptic transmission. By in silico analysis of the proximal KCC2 promoter region we identified 10 candidate transcription factor binding sites that are highly conserved in mammalian KCC2 genes. One of these transcription factors, namely early growth response factor 4 (Egr4), had similar developmental profile as KCC2 and considerably increased the activity of mouse KCC2 gene in neuronal cells. Next we investigated the involvement of neurotrophic factors in regulation of Egr4 and KCC2 expression. We found that in immature hippocampal cultures Egr4 and KCC2 levels were strongly up-regulated by brain derived neurotrophic factor (BDNF)and neurturin. The effect of neurotrophic factors was dependent on the activation of a mitogen activated protein kinase (MAPK) signal transduction pathway. Intact Egr4-binding site in proximal KCC2 promoter was required for BDNF-induced KCC2 transcription. In vitro data were confirmed by several in vivo experiments where we detected an upregulation of KCC2 protein levels after intrahippocampal administration of BDNF or neurturin. Importantly, a MAPK-dependent rise in Egr4 and KCC2 expression levels was also observed after a period of kainic acid-induced seizure activity in neonatal rats suggesting that neuronal activity might be involved in Egr4-mediated regulation of KCC2 expression. Finally we demonstrated that the mammalian KCC2 gene (alias Slc12a5) generated two neuron-specific isoforms by using alternative promoters and first exons. A novel isoform of KCC2, termed KCC2a, differed from the previously known KCC2b isoform by 40 unique N-terminal amino acid residues. KCC2a expression was restricted to CNS,remained relatively constant during postnatal development, and contributed 20 50% of total KCC2 mRNA expression in the neonatal mouse brainstem and spinal cord. In summary, our data provide insight into the complex regulation of KCC2 expression during early postnatal development. Although basal KCC2 expression seems to be intrinsically regulated, it can be further augmented by neurotrophic factors or by enhanced activity triggering MAPK phosphorylation and Egr4 induction. Additional KCC2a isoform, regulated by another promoter, provides basal KCC2 level in neonatal brainstem and spinal cord required for survival of KCC2b knockout mice.

Day Surgery in Finland : randomized and cross-sectional studies on treatment, quality, and outcome

The aims of this study were to describe Finnish day surgery practice at present and to evaluate quality of care by assessing postdischarge minor morbidity and quality indicators. Potential treatment options were approached by investigating the role of oral dexamethasone as a part of multimodal analgesia and the feasibility of day surgery in patients aged 65 years and older. Over a 2-month period, all patient cases at 14 Finnish day surgery or short-stay units were analyzed (Study I). Quality indicators included rates and reasons for overnight admission, readmission, reoperation, cancellations, and patient satisfaction. Recovery during the first postoperative week was assessed at two units (Study II). Altogether 2732 patients graded daily the intensity of predefined symptoms. To define risk factors of postdischarge symptoms, multinomial regression analysis was used. Sixty patients scheduled to undergo day surgery for hallux valgus were randomized to receive twice perioperatively dexamethasone 9 mg or placebo (Study III). Paracetamol 1 g was administered 3 times daily. Rescue medication (oxycodone) consumption during 0-3 postoperative days (POD), maximal pain scores and adverse effects were documented. Medically stable patients aged 65 years or older, scheduled for open inguinal hernia repair, were randomized to receive treatment either as day cases or inpatients (Study IV). Complications, unplanned admissions, healthcare visits, and patients’ acceptance of the type of care provided were assessed during 2 weeks postoperatively. In Study I, unplanned overnight admissions were reported in 5.9%, return hospital visits during PODs 1-28 in 3.7%, and readmissions in 0.7% of patients. Patient satisfaction was high. In Study II, pain was the most common symptom in adult patients (57%). Postdischarge symptoms were more frequent in adults aged < 40 years, children aged ≥ 7 years, females, and following a longer duration of surgery. In Study III, the total median (range) oxycodone consumption during the study period was 45 (0–165) mg in the dexamethasone group, compared with 78 (15–175) mg in the placebo group (P < 0.049). On PODs 0-1, patients in the dexamethasone group reported significantly lower pain scores. Following inguinal hernia repair, no significant differences in outcome measures were seen between the study groups. Patient satisfaction was equally high in day cases and inpatients (Study IV). Finnish day surgery units provide good-quality services. Minor postdischarge symptoms are common, and they are influenced by several patient-, surgery-, and anesthesia-related factors. Oral dexamethasone combined with paracetamol improves pain relief and reduces the need for oxycodone rescue medication following correction of hallux valgus. Day surgery for open inguinal hernia repair is safe and well accepted by patients aged 65 years or older and can be recommended as the primary choice of care for medically stable patients.

Water in Action : Encounters among 2- to 3-Year-Old Children, Adults, and Water in Day Care

In line with cultural psychology and developmental theory, a single case approach is applied to construct knowledge on how children s interaction emerge interlinked to historical, social, cultural, and material context. The study focuses on the negotiation of constraints and meaning construction among 2-to 3-year-old children, a preschool teacher, and the researcher in settings with water. Water as an element offers a special case of cultural canalization: adults selectively monitor and guide children s access to it. The work follows the socio-cultural tradition in psychology, particularly the co-constructivist theory of human development and the Network of Meanings perspective developed at the University of São Paulo. Valsiner s concepts of Zone of Free Movement and Zone of Promoted Action are applied together with studies where interactions are seen as spaces of construction where negotiation of constraints for actions, emotions, and conceptions occur. The corpus was derived at a Finnish municipal day care centre. During a seven months period, children s actions were video recorded in small groups twice a month. The teacher and the researcher were present. Four sessions with two children were chosen for qualitative microanalysis; the analysis also addressed the transformations during the months covered by the study. Moreover, the data derivation was analyzed reflectively. The narrowed down arenas for actions were continuously negotiated among the participants both nonverbally and verbally. The adults expectations and intentions were materialized in the arrangements of the setting canalizing the possibilities for actions. Children s co-regulated actions emerged in relation to the adults presence, re-structuring attempts, and the constraints of the setting. Children co-constructed novel movements and meanings in relation to the initiatives and objects offered. Gestures, postures, and verbalizations emerged from the initially random movements and became constructed to have specific meanings and functions; meaning construction became abbreviated. The participants attempted to make sense of the ambiguous (explicit and implicit) intentions and fuzzy boundaries of promoted and possible actions: individualized yet overlapping features were continuously negotiated by all the participants. Throughout the months, children s actions increasingly corresponded adults (re-defined) conceptions of water researchers as an emerging group culture. Water became an instrument and a context for co-regulations. The study contributes to discussions on children as participants in cultural canalization and emphasizes the need for analysis in early childhood education practices on the implicit and explicit constraint structures for actions.

Fast in-memory XPath search using compressed indexes

A large fraction of an XML document typically consists of text data. The XPath query language allows text search via the equal, contains, and starts-with predicates. Such predicates can be efficiently implemented using a compressed self-index of the document's text nodes. Most queries, however, contain some parts querying the text of the document, plus some parts querying the tree structure. It is therefore a challenge to choose an appropriate evaluation order for a given query, which optimally leverages the execution speeds of the text and tree indexes. Here the SXSI system is introduced. It stores the tree structure of an XML document using a bit array of opening and closing brackets plus a sequence of labels, and stores the text nodes of the document using a global compressed self-index. On top of these indexes sits an XPath query engine that is based on tree automata. The engine uses fast counting queries of the text index in order to dynamically determine whether to evaluate top-down or bottom-up with respect to the tree structure. The resulting system has several advantages over existing systems: (1) on pure tree queries (without text search) such as the XPathMark queries, the SXSI system performs on par or better than the fastest known systems MonetDB and Qizx, (2) on queries that use text search, SXSI outperforms the existing systems by 1-3 orders of magnitude (depending on the size of the result set), and (3) with respect to memory consumption, SXSI outperforms all other systems for counting-only queries.

Growing up in Affiliation with a Religious Community : A Case Study of Seventh-day Adventist Youth in Finland

This study investigates how the religious community as a socialization context affects the development of young people's religious identity and values, using Finnish Seventh-day Adventism as a context for the case study. The research problem is investigated through the following questions: (1) What aspects support the intergenerational transmission of values and tradition in religious home education? (2) What is the role of social capital and the social networks of the religious community in the religious socialization process? (3) How does the religious composition of the peer group at school (e.g., a denominational school in comparison to a mainstream school) affect these young people s social relations and choices and their religious identity (as challenged versus as reinforced by values at school)? And (4) How do the young people studied negotiate their religious values and religious membership in the diverse social contexts of the society at large? The mixed method study includes both quantitative and qualitative data sets (3 surveys: n=106 young adults, n=100 teenagers, n=55 parents; 2 sets of interviews: n=10 young adults and n=10 teenagers; and fieldwork data from youth summer camps). The results indicate that, in religious home education, the relationship between parents and children, the parental example of a personally meaningful way of life, and encouraging critical thinking in order for young people to make personalized value choices were important factors in socialization. Overall, positive experiences of the religion and the religious community were crucial in providing direction for later choices of values and affiliations. Education that was experienced as either too severe or too permissive was not regarded as a positive influence for accepting similar values and lifestyle choices to those of the parents. Furthermore, the religious community had an important influence on these young people s religious socialization in terms of the commitment to denominational values and lifestyle and in providing them with religious identity and rooting them in the social network of the denomination. The network of the religious community generated important social resources, or social capital, for both the youth and their families, involving both tangible and intangible benefits, and bridging and bonding effects. However, the study also illustrates the sometimes difficult negotiations the youth face in navigating between differentiation and belonging when there is a tension between the values of a minority group and the larger society, and one wants to and does belong to both. It also demonstrates the variety within both the majority and the minority communities in society, as well as the many different ways one can find a personally meaningful way of being an Adventist. In the light of the previous literature about socialization-in-context in an increasingly pluralistic society, the findings were examined at four levels: individual, family, community and societal. These were seen as both a nested structure and as constructing a funnel in which each broader level directs the influences that reach the narrower ones. The societal setting directs the position and operation of religious communities, families and individuals, and the influences that reach the developing children and young people are in many ways directed by societal, communal and family characteristics. These levels are by nature constantly changing, as well as being constructed of different parts, like the pieces of a jigsaw puzzle, each of which alters in significance: for some negotiations on values and memberships the parental influence may be greater, whereas for others the peer group influences are. Although agency does remain somewhat connected to others, the growing youth are gradually able to take more responsibility for their own choices and their agency plays a crucial role in the process of choosing values and group memberships. Keywords: youth, community, Adventism, socialization, values, identity negotiations

The expiration day effect of indexoptions and index futures on the underlying shares

This paper studies the effect of the expiration day of index options and futures on the trading volume, variance and price of the underlying shares. The data consists of all trades for the underlying shares in the FOX-index for expiration days during the period October 1995 to the mid of yer 1999. The main results seem to support the findings of Kan 2001, i.e. no manipulation on a larger scale. However, some indication of manipulation could be found if certain characteristics are favorable. These characteristics include: a) a large quantity of outstanding futures or at/in the money options contracts, b) there exists shares with high index weight but fairly low trading volume. Lastly, there is some indication that manipulation might be more popular towards the end of the examined time period.

Bootstrap and Fast Double Bootstrap Tests of Cointegration Rank with Financial Time Series

The likelihood ratio test of cointegration rank is the most widely used test for cointegration. Many studies have shown that its finite sample distribution is not well approximated by the limiting distribution. The article introduces and evaluates by Monte Carlo simulation experiments bootstrap and fast double bootstrap (FDB) algorithms for the likelihood ratio test. It finds that the performance of the bootstrap test is very good. The more sophisticated FDB produces a further improvement in cases where the performance of the asymptotic test is very unsatisfactory and the ordinary bootstrap does not work as well as it might. Furthermore, the Monte Carlo simulations provide a number of guidelines on when the bootstrap and FDB tests can be expected to work well. Finally, the tests are applied to US interest rates and international stock prices series. It is found that the asymptotic test tends to overestimate the cointegration rank, while the bootstrap and FDB tests choose the correct cointegration rank.

The Day of the Week Effect and Option Pricing - A Study of the German Option Market

The use of different time units in option pricing may lead to inconsistent estimates of time decay and spurious jumps in implied volatilities. Different time units in the pricing model leads to different implied volatilities although the option price itself is the same.The chosen time unit should make it necessary to adjust the volatility parameter only when there are some fundamental reasons for it and not due to wrong specifications of the model. This paper examined the effects of option pricing using different time hypotheses and empirically investigated which time frame the option markets in Germany employ over weekdays. The paper specifically tries to get a picture of how the market prices options. The results seem to verify that the German market behaves in a fashion that deviates from the most traditional time units in option pricing, calendar and trading days. The study also showed that the implied volatility of Thursdays was somewhat higher and thus differed from the pattern of other days of the week. Using a GARCH model to further investigate the effect showed that although a traditional tests, like the analysis of variance, indicated a negative return for Thursday during the same period as the implied volatilities used, this was not supported using a GARCH model.

Fast- and drift-ice communities in the Bothnian Bay and the impact of UVA radiation on the Baltic Sea ice ecology

The aim of this thesis was to study ecology of Baltic Sea ice from two perspectives. In the first two studies, sea-ice ecology from riverine-influenced fast ice to drift ice in the Bothnian Bay was investigated, whereas the last two studies focus on the sensitivity of sea-ice bacteria and algae to UVA examined in situ. The seasonal sea ice cover is one of the main characteristics of the Baltic Sea, and despite the brackish parental water, the ice structure is similar to polar ice with saline brine inclusions, the sea ice habitat. The decreasing seawater salinity from the northern Baltic Sea to the Bothnian Bay translates to decreasing brine volumes along the gradient, governing the size and community structure of the food webs in ice. However, the drift and fast ice in the Bothnian Bay may differ greatly in this sense, as drift ice may have been formed at more southern locations. Rafting and the formation of snow ice are common processes in the ice field of the Bothnian Bay. As evidenced in this thesis, rafting altered the vertical distribution of organisms and snow-ice formation provided habitable space in the better-illuminated, nitrogen-rich surface layer. The divergence between fast and drift ice became apparent at the more advanced stages, and chlorophyte biomass decreased from fast to drift ice, while the opposite held true for protozoan and metazoan biomass. The brine volumes affected the communities somewhat, and a higher percentage of flagellate species was generally linked to lower brine volumes, whereas chain-forming diatoms were mostly concentrated in layers with larger brine volumes. These results add to knowledge of the ecological significance of the ice cover lasting up to 7 months per year in this area. Sea-ice food webs are generally light-limited, but while increasing light irradiances typically enhance the primary production and further, the secondary production in sea ice, any increase in solar radiation also includes an increase in harmful UVA radiation. The Baltic Sea ice microbial communities were clearly sensitive to UVA and the responses were strongly linked to the earlier light history, as well as to the solar irradiances they were exposed to. The increased biomass of chlorophytes and pennate diatoms, when UVA was excluded, indicates that their normally minor contribution to the biomass in the upper layers of sea ice might be partly dictated by UVA. The effects of UVA on bacterial production in Baltic Sea ice mostly followed the responses in algal growth, but occasionally the exposure to UVA even enhanced the bacterial production. The dominant bacterial class, Flavobacteria, seemed to be UVA-tolerant, whereas all the Alpha-, Beta- and Gammaproteobacteria present in the surface layer showed UVA sensitivity. These results indicate that changes in the light field of ice may alter the community structure and affect the functioning of ice food webs, and are of importance when the effects of thinning of the ice cover are assessed.