The purpose of the study was to examine the effects of a workplace physical exercise intervention on the perceived intensity of headache and the intensity of symptoms in the neck and shoulders, as well as on the extension and flexion strength of the upper extremities. The study was a cluster randomized controlled trial. The cross-over design consisted of physical exercise intervention (15 weeks) and no-intervention (15 weeks). The subjects (n=53) were office workers (mean age 46.6 (SD 8.4)) who reported headache (n=41) symptoms in the neck (n=37) or shoulders (n=41), which had restricted their daily activities during the last 12 months. Pain symptoms were measured using the Borg CR10 scale and muscular strength with a 5RM test. Statistical analyses were based on linear mixed models. Physical exercise intervention resulted in a slight, but statistically significant, decrease in the intensity of headache and neck symptoms, as well as an increase in the extension strength of the upper extremities. The mean decrease in headache during the 5-week period was 0.64 CR10 (95% CI 0.28-1.00) (P=0.001) or 49% (95% CI 22-77), and 0.42 CR10 (95% CI 0.11-0.72) (P=0.002) or 49% (95% CI 13-85) in the intensity of neck symptoms. The mean increase in the extension strength of the upper extremities was 1.3 kg (95% CI 0.5-2.1) (P=0.001) or 4% (95% CI 1-6). The intervention had no effect on the intensity of shoulder symptoms or the flexion strength of the upper extremities. Specific exercise may be clinically important to alleviate headache and neck symptoms.

The purpose of the study was to examine the effects of a workplace physical exercise intervention on subjective physical well-being, psychosocial functioning and general well-being. The study was a cluster randomized-controlled trial with the department (n=4) as the unit of randomization. The subjects (n=90) were office workers [mean age 45.7 (SD 8.5) years]. Psychosocial functioning and well-being variables were measured by descriptive visual rating scales. The cross-over design consisted of one 15-week intervention period of light resistance training and guidance and another 15-week period of no training and no guidance. The statistical analysis was based on linear mixed models. The active component of the intervention, light resistance training, resulted in a slight, but statistically significant, increase in subjective physical well-being (P=0.015). At the average training time of 5 min/working day (25 min/week) the average increase during the 15-week period was 4 units (95% confidence interval (CI) 1-7) and 5% (95% CI 1-9). The physical exercise intervention had no effect on somatic symptoms, anxiety, self-confidence, mood, mental stress at work, working atmosphere, life satisfaction or meaning of life. Daily light resistance training, conducted during the working day, had a positive direction on subjective physical well-being among office workers.

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Understanding the effects of inbreeding and genetic drift within populations and hybridization between genetically differentiated populations is important for many basic and applied questions in ecology and evolutionary biology. The magnitudes and even the directions of these effects can be influenced by various factors, especially by the current and historical population size (i.e. inbreeding rate). Using Drosophila littoralis as a model species, we studied the effect of inbreeding rate over a range of inbreeding levels on (i) mean fitness of a population (relative to that of an outbred control population), (ii) within-population inbreeding depression (reduction in fitness of offspring from inbred versus random mating within a population) and (iii) heterosis (increase in fitness of offspring from interpopulation versus within-population random mating). Inbreeding rate was manipulated by using three population sizes (2, 10 and 40), and fitness was measured as offspring survival and fecundity. Fast inbreeding (smaller effective population size) resulted in greater reduction in population mean fitness than slow inbreeding, when populations were compared over similar inbreeding coefficients. Correspondingly, populations with faster inbreeding expressed more heterosis upon interpopulation hybridization. Inbreeding depression within the populations did not have a clear relationship with either the rate or the level of inbreeding.

Summary 1.The breeding success of Finnish grouse has been in decline for decades. While it has been shown that fragmentation and modern forestry practices such as clear-cutting affect the viability of grouse populations, little is known about effects of large-scale drainage. The drainage network in Finland has increased dramatically during the past decades. By 1988, 6 million ha of bog ecosystems had been drained. This is likely to have had a profound direct and indirect effects on grouse productivity. Because ditches persist in time, large-scale drainage may therefore have strong potential for affecting the long-term breeding success of three forest grouse species in Finland. 2. Using a mixed-model approach on nation-wide data, we estimate the effects of drainage on breeding success of three grouse species for the period from 1966 to 1988. The possible additive effect of precipitation is investigated using regional precipitation data. For each species, we compare a set of hypotheses and select the best model(s) according to the Akaike information criterion. 3. For all species, the model which included the main effects of both ditch density and precipitation outperformed the models with just one of the main effects as well as the interaction model. The effects are restricted to southern and central Finland, where drainage is most intensive. 4. The effects of drainage are likely to be both direct and indirect, but the mechanisms are less clear. Both bottom-up, such as decreased availability of insect food, and top-down effects, such as increased predation risk, may account for indirect effects. Direct effects are likely to involve drowning of chicks. 5. Synthesis and applications . Bogs are classified as key biotopes by the European Union, and Finland is obliged to maintain their favourable conservation status and to protect typical bog communities. While this goal may be achieved for state-owned land, restoration of drainage systems on private land continues. Considering the persistence of ditches, new legislation are therefore needed to favour the recovery of former bogs and mires on private land as well as to protect remaining ones.