ETYK III-vaihe: Tasavallan Presidentin päätössanat 1.8.1975 = Third Stage of the CSCE = closing statement by the President of Finland August 1, 1975

Puhe

Tasavallan Presidentin tervehdyssanat Euroopan turvallisuus- ja yhteistyökonferenssin avajaisissa Helsingissä 3.7.1973 = speech of welcome by the President of the Republic, Dr. Urho Kekkonen, at the inaugural session of CSCE in Helsinki, July 3rd, 1973

Puhe

Optimization of the procedure for removing iron deposits on ceramic filter media

In this thesis, cleaning of ceramic filter media was studied. Mechanisms of fouling and dissolution of iron compounds, as well as methods for cleaning ceramic membranes fouled by iron deposits were studied in the literature part. Cleaning agents and different methods were closer examined in the experimental part of the thesis. Pyrite is found in the geologic strata. It is oxidized to form ferrous ions Fe(II) and ferric ions Fe(III). Fe(III) is further oxidized in the hydrolysis to form ferric hydroxide. Hematite and goethite, for instance, are naturally occurring iron oxidesand hydroxides. In contact with filter media, they can cause severe fouling, which common cleaning techniques competent enough to remove. Mechanisms for the dissolution of iron oxides include the ligand-promoted pathway and the proton-promoted pathway. The dissolution can also be reductive or non-reductive. The most efficient mechanism is the ligand-promoted reductive mechanism that comprises two stages: the induction period and the autocatalytic dissolution.Reducing agents(such as hydroquinone and hydroxylamine hydrochloride), chelating agents (such as EDTA) and organic acids are used for the removal of iron compounds. Oxalic acid is the most effective known cleaning agent for iron deposits. Since formulations are often more effective than organic acids, reducing agents or chelating agents alone, the citrate¿bicarbonate¿dithionite system among others is well studied in the literature. The cleaning is also enhanced with ultrasound and backpulsing.In the experimental part, oxalic acid and nitric acid were studied alone andin combinations. Also citric acid and ascorbic acid among other chemicals were tested. Soaking experiments, experiments with ultrasound and experiments for alternative methods to apply the cleaning solution on the filter samples were carried out. Permeability and ISO Brightness measurements were performed to examine the influence of the cleaning methods on the samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the solutions was carried out to determine the dissolved metals.

The effect of the birth hospital and the time of birth on the outcome of Finnish very preterm infants

The purpose of this study was to evaluate the effect of the birth hospital and the time of birth on mortality and the long-term outcome of Finnish very low birth weight (VLBW) or very low gestational age (VLGA) infants. This study included all Finnish VLBW/VLGA infants born at <32 gestational weeks or with a birth weight of ≤1500g, and controls born full-term and healthy. In the first part of the study, the mortality of VLBW/VLGA infants born in 2000–2003 was studied. The second part of the study consisted of a five-year follow-up of VLBW/VLGA infants born in 2001–2002. The study was performed using data from parental questionnaires and several registers. The one-year mortality rate was 11% for live-born VLBW/VLGA infants, 22% for live-born and stillborn VLBW/VLGA infants, and 0% for the controls. In live-born and in all (including stillbirths) VLBW/VLGA infants, the adjusted mortality was lower among those born in level III hospitals compared with level II hospitals. Mortality rates of live-born VLBW/VLGA infants differed according to the university hospital district where the birth hospital was located, but there were no differences in mortality between the districts when stillborn infants were included. There was a trend towards lower mortality rates in VLBW/VLGA infants born during office hours compared with those born outside office hours (night time, weekends, and public holidays). When stillborn infants were included, this difference according to the time of birth was significant. Among five-year-old VLBW/VLGA children, morbidity, use of health care resources, and problems in behaviour and development were more common in comparison with the controls. The health-related quality of life of the surviving VLBW/VLGA children was good but, statistically, it was significantly lower than among the controls. The median and the mean number of quality-adjusted life-years were 4.6 and 3.6 out of a maximum five years for all VLBW/VLGA children. For the controls, the median was 4.8 and the mean was 4.9. Morbidity rates, the use of health care resources, and the mean quality-adjusted life-years differed for VLBW/VLGA children according to the university hospital district of birth. However, the time of birth, the birth hospital level or university hospital district were not associated with the health-related quality of life, nor with behavioural and developmental scores of the survivors at the age of five years. In conclusion, the decreased mortality in level III hospitals was not gained at the expense of long-term problems. The results indicate that VLBW/VLGA deliveries should be centralized to level III hospitals and the regional differences in the treatment practices should further be clarified. A long-term follow-up on the outcome of VLBW/VLGA infants is important in order to recognize the critical periods of care and to optimise the care. In the future, quality-adjusted life-years can be used as a uniform measure for comparing the effectiveness of care between VLBW/VLGA infants and different patient groups

Effects of algal turbidity on foraging and antipredator behaviour of the three-spined stickleback (Gasterosteus aculeatus)

The aim of this thesis was to examine how aquatic organisms, such as fish, behave in an altered environmental condition. Many species of fish use vision as their primary tool to gain information about their surrounding environment. The visual conditions of aquatic habitats are often altered as a result of anthropogenic disturbance, such as eutrophication that initiates algal turbidity. In general, turbidity reduces the visibility and can be hypothesized to have an influence on the behaviour of fish. I used the three-spined stickleback (Gasterosteus aculeatus) as a model species and conducted four studies in the laboratory to test how algal turbidity affects its behaviour. In this thesis, two major behavioural aspects are discussed. The first is antipredator behaviour. In study I, the combined effects of turbidity and shoot density on habitat choice (shelter vs open) behaviour was tested on a group of sticklebacks (20 fish) in the presence and absence of piscivorous perch (Perca fluviatilis). In study II, I examined the behavioural responses of feeding sticklebacks when they were exposed to the sudden appearance of an avian predator (the silhouette of a common tern, Sterna hirundo). The study was done in turbid and clear water using three different groups sizes (1, 3 and 6 fish). The second aspect is foraging behaviour. Study III & IV focused on the effects of algal turbidity on the foraging performance of sticklebacks. In study III, I conducted two separate experiments to examine the effects of turbidity on prey consumption and prey choice of sticklebacks. In this experiment turbidity levels and the proportion of large and small prey (Daphnia spp.) were manipulated. In study IV, I studied whether a group of six sticklebacks can distribute themselves according to food input at two feeding stations in a way that provided each fish with the same amount of food in clear and turbid water. I also observed whether the fish can follow changes in resource distribution between the foraging patches. My results indicate an overall influence of algal turbidity on the antipredator and foraging behaviour of sticklebacks. In the presence of a potential predator, the use of the sheltered habitat was more pronounced at higher turbidity. Besides this, sticklebacks reduced their activity levels with predator presence at higher turbidity and shoot density levels, suggesting a possible antipredator adaptation to avoid a predator. When exposed to a sudden appearance of an avian predator, sticklebacks showed a weaker antipredator response in turbid water, which suggests that turbidity degrades the risk assessment capabilities of sticklebacks. I found an effect of group size but not turbidity in the proportion of sticklebacks that fled to the shelter area, which indicates that sticklebacks are able to communicate among group members at the experimental turbidity levels. I found an overall negative effect of turbidity on food intake. Both turbidity and changes in the proportion of prey sizes played a significant role in a stickleback’s prey selection. At lower turbidity levels (clear <1 and 5 NTU) sticklebacks showed preferences for large prey, whereas in more turbid conditions and when the proportion of large to small prey increased sticklebacks became increasingly random in their prey selection. Finally, my results showed that groups of sticklebacks disperse themselves between feeding stations according to the reward ratios following the predictions of the ideal free distribution theory. However, they took a significantly longer time to reach the equilibrium distribution in turbid water than in clear water. In addition, they showed a slower response to changes in resource distribution in a turbid environment. These findings suggest that turbidity interferes with the information transfer among group foragers. It is important to understand that aquatic animals are often exposed to a degraded environment. The findings of this thesis suggest that algal turbidity negatively affects their behavioural performance. The results also shed light on the underlying behavioural strategies of sticklebacks in turbid conditions that might help them adapt to an altered environmental situation and increase their survival. In conclusion, I hold that although algal turbidity has detrimental effects on the antipredator and foraging behaviour of sticklebacks, their behavioural adjustment might help them adapt to a changing environment.