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  • Granström, Mari (Helsingin yliopisto, 2009)
    Even though cellulose is the most abundant polymer on Earth, its utilisation has some limitations regarding its efficient use in the production of bio-based materials. It is quite clear from statistics that only a relatively small fraction of cellulose is used for the production of commodity materials and chemicals. This fact was the driving force in our research into understanding, designing, synthesising and finding new alternative applications for this well-known but underused biomaterial. This thesis focuses on the developing advanced materials and products from cellulose by using novel approaches. The aim of this study was to investigate and explore the versatility of cellulose as a starting material for the synthesis of cellulose-based materials, to introduce new synthetic methods for cellulose modification, and to widen the already existing synthetic approaches. Due to the insolubility of cellulose in organic solvents and in water, ionic liquids were applied extensively as the reaction media in the modification reactions. Cellulose derivatives were designed and fine-tuned to obtain desired properties. This was done by altering the inherent hydrogen bond network by introducing different substituents. These substituents either prevented spontaneous formation of hydrogen bonding completely or created new interactions between the cellulose chains. This enabled spontaneous self-assembly leading to supramolecular structures. It was also demonstrated that the material properties of cellulose can be modified even those molecules with a low degree of substitution when highly hydrophobic films and aerogels were prepared from fatty acid derivatives of nanocellulose. Development towards advanced cellulose-based materials was demostrated by synthesising chlorophyllcellulose derivatives that showed potential in photocurrent generation systems. In addition, liquid crystalline cellulose derivatives prepared in this study, showed to function as UV-absorbers in paper.
  • Kuutti, Lauri (Helsingin yliopisto, 2013)
    Despite the similarity of their structural basic units, cellulose- and starch-based materials behave differently in many industrial applications. In this thesis, the structure and properties of these polysaccharides and their selected derivatives were studied by means of five comprehensive examples. In the first investigation, highly crystalline cellulose was identified from Valonia macrophysa vesicles by atomic force microscopy. The role of water as a possible modifier on the surface of cellulose was found to be very important. The monoclinic phases were found on the cellulose surfaces with a lateral resolution of about 4 Å, indicating that water molecules cannot penetrate and thus disturb the surface structure of monoclinic cellulose. On the other hand, the absence of triclinic phases was explained by the used measuring geometry without liquid cell. The ageing of metastable oat and barley thermoplastic starch films was followed by frictional imaging. As a consequence of the ageing, the films lose some of their mechanical properties. In the oat films, glycerol used as a plasticiser diffused from the starch-glycerol-water matrix to the surface of thermoplastic starch, resulting in areas with low friction. In the case of barley starch films, the ageing first resulted in short range reorientation of polymers and finally slow crystallization of amylopectin branches. Solution precipitation techniques were applied to produce ideally spherical starch ester particles (with a diameter about half the wavelength of visible light), suitable for fillers in paper coatings in the third study. Particles assume their shape and size spontaneously when solvated starch polymer is mixed with non-solvent, due to the free mobility of the modified starch chains. Starch pigment has improved affinity to paper surface and it can be used as such or mixed with other pigments to enhance the optical or printing properties of paper. Starch-based pigmenting materials with improved optical performance were prepared in the laboratory by the complexation approach. Analytical results indicated that the complexation of carboxymethyl starch and inorganics strongly depends on the carboxymethyl group in the starch-based hybrid pigmented materials. The formed insoluble hybrids were mostly amorphous and the crystalline contribution of the inorganic component was not evident. The resulting precipitates exhibited composite structures. Finally, three starch-based and two cellulose-based polymers were selected for flocculation and filtration tests. In shearless dewatering conditions, the retention and dewatering properties of the starch-based polymers were similar to those of commercial polyacrylamide-based polymers. The flow studies in higher shear conditions showed that with the studied dosages the starch-based polymers could not reach the flocculation levels needed to maintain sufficient retention properties. The performance of the cellulose-based polymers as flocculating agents was less efficient. The reasons for the more limited performance of the polysaccharide-based flocculants were too low molecular weight and the charge density distribution. Better understanding of how to improve the hydrodynamic properties of bio-based polymers will be essential when planning new bio-based flocculants. The deeper understanding of the relationships between the desired structures and properties of polysaccharides helps to utilize them more effectively. In this way it is possible to obtain better bio-based and environmentally sustainable products in the competition with the current products based on conventional petrochemistry.
  • Holopainen, Juha (Helsingin yliopisto, 2001)
  • Linko-Parvinen, Anna-Maria (Helsingin yliopisto, 2006)
    Several studies link the consumption of whole-grain products to a lowered risk of chronic diseases, such as certain types of cancer, type II diabetes, and cardiovascular diseases. However, the final conclusions of the exact protective mechanisms remain unclear, partly due to a lack of a suitable biomarker for the whole-grain cereals intake. Alkylresorcinols (AR) are phenolic lipids abundant in the outer parts of wheat and rye grains usually with homologues of C15:0- C25:0 alkyl chains, and are suggested to function as whole-grain biomarkers. Mammalian lignan enterolactone has also previously been studied as a potential whole-grain biomarker. In the present work a quantified gas chromatography-mass spectrometry method for the analysis of AR in plasma, erythrocytes, and lipoproteins was developed. The method was used to determine human and pig plasma AR concentrations after the intake of whole-grain wheat and rye products compared to low-fibre wheat bread diets to assess the usability of AR as biomarkers of whole-grain intake. AR plasma concentrations were compared to serum ENL concentrations. AR absorption and elimination kinetics were investigated in a pig model. AR occurrence in human erythrocyte membranes and plasma lipoproteins were determined, and the distribution of AR in blood was evaluated. Plasma AR seem to be absorbed via the lymphatic system from the small intestine, like many other lipophilic compounds. Their apparent elimination half-life is relatively short and is similar to that of tocopherols, which have a similar chemical structure. Plasma AR concentrations increased significantly after a one- to eight-week intake of whole-grain wheat and further on with whole-grain rye bread. The concentrations were also higher after habitual Finnish diet compared to diet with low-fibre bread. Inter-individual variation after a one-week intake of the same amount of bread was high, but the mean plasma AR concentrations increased with increasing AR intake. AR are incorporated into erythrocyte membranes and plasma lipoproteins, and VLDL and HDL were the main AR carriers in human plasma. Based on these studies, plasma AR could function as specific biomarkers of dietary whole-grain products. AR are exclusively found in whole-grains and are more suitable as specific biomarkers of whole-grain intake than previously investigated mammalian lignan enterolactone, that is formed from several plants other than cereals in the diet. Plasma AR C17:0/C21:0 -ratio could distinguish whether whole-grain products in the diet are mainly wheat or rye. AR could be used in epidemiological studies to determine whole-grain intake and to better assess the role of whole-grains in disease prevention.
  • Hannikainen, Heikki (2013)
    Background and purpose: Cerebral venous thrombosis (CVT) is a rare, but serious disease, commonly occurring in young to middle‐aged women. It is not yet known whether sinus size and shape confers a risk for thrombosis and whether clot size is correlated with recanalization rates, and because there is no established method for measuring sinus or clot size, we decided to develop one. Patients and methods: CVT patients with 3‐D magnetic resonance imaging done early for diagnosis and follow‐up imaging around 6 months or later were recruited. Age and sexmatched (1:2) control subjects were patients with various benign headache problems who underwent 3D MRI for excluding CVT or other acute structural disease. All major sinuses were measured in size (area and diameter). All detected clots underwent similar measurement (volume, area and length). Measurements were done with Osirix‐software. Results: 25 CVT patients (17 females and 8 males) and 50 control subjects were measured. Volume of the thrombus was either dissolved or reduced in all except one case. Sinus area in CVT patients in follow‐up imaging was slightly smaller compared to healthy subjects ( P=0.052‐0.170). Thrombus volumes were bigger (P=0.009) but also dissolved more effectively in women, with no difference in sex‐groups in follow‐up imaging. Residual clot volume was bigger in older patients (P=0.007). Other factors did not strongly correlate with thrombus volume. Measurement reproducibility with two individual investigators was good, with best interrater correlation of over 95% in volume measures. Conclusions: This is the first attempt in establishing a volumetric measurement of cerebral sinuses and clots. The methodology may help in estimating probability of recanalization and in trials with interventions such as local thrombolysis and thrombectomy.
  • Hannikainen, Heikki (2014)
    Background and purpose: Cerebral venous thrombosis (CVT) is a rare, but serious disease, commonly occurring in young to middle‐aged women. It is not yet known whether sinus size and shape confers a risk for thrombosis and whether clot size is correlated with recanalization rates, and because there is no established method for measuring sinus or clot size, we decided to develop one. Patients and methods: CVT patients with 3‐D magnetic resonance imaging done early for diagnosis and follow‐up imaging around 6 months or later were recruited. Age and sexmatched (1:2) control subjects were patients with various benign headache problems who underwent 3D MRI for excluding CVT or other acute structural disease. All major sinuses were measured in size (area and diameter). All detected clots underwent similar measurement (volume, area and length). Measurements were done with Osirix‐software. Results: 25 CVT patients (17 females and 8 males) and 50 control subjects were measured. Volume of the thrombus was either dissolved or reduced in all except one case. Sinus area in CVT patients in follow‐up imaging was slightly smaller compared to healthy subjects ( P=0.052‐0.170). Thrombus volumes were bigger (P=0.009) but also dissolved more effectively in women, with no difference in sex‐groups in follow‐up imaging. Residual clot volume was bigger in older patients (P=0.007). Other factors did not strongly correlate with thrombus volume. Measurement reproducibility with two individual investigators was good, with best interrater correlation of over 95% in volume measures. Conclusions: This is the first attempt in establishing a volumetric measurement of cerebral sinuses and clots. The methodology may help in estimating probability of recanalization and in trials with interventions such as local thrombolysis and thrombectomy.
  • Nikkilä, Heikki (Helsingin yliopisto, 2000)
  • Constantin, Camelia (Helsingin yliopisto, 2008)
    B. cereus is one of the most frequent occurring bacteria in foods . It produces several heat-labile enterotoxins and one stable non-protein toxin, cereulide (emetic), which may be pre-formed in food. Cereulide is a heat stable peptide whose structure and mechanism of action were in the past decade elucidated. Until this work, the detection of cereulide was done by biological assays. With my mentors, I developed the first quantitative chemical assay for cereulide. The assay is based on liquid chromatography (HPLC) combined with ion trap mass spectrometry and the calibration is done with valinomycin and purified cereulide. To detect and quantitate valinomycin and cereulide, their [NH4+] adducts, m/z 1128.9 and m/z 1171 respectively, were used. This was a breakthrough in the cereulide research and became a very powerful tool of investigation. This tool made it possible to prove for the first time that the toxin produced by B. cereus in heat-treated food caused human illness. Until this thesis work (Paper II), cereulide producing B. cereus strains were believed to represent a homogenous group of clonal strains. The cereulide producing strains investigated in those studies originated mostly from food poisoning incidents. We used strains of many origins and analyzed them using a polyphasic approach. We found that the cereulide producing B. cereus strains are genetically and biologically more diverse than assumed in earlier studies. The strains diverge in the adenylate kinase (adk) gene (two sequence types), in ribopatterns obtained with EcoRI and PvuII (three patterns), tyrosin decomposition, haemolysis and lecithine hydrolysis (two phenotypes). Our study was the first demonstration of diversity within the cereulide producing strains of B. cereus. To manage the risk for cereulide production in food, understanding is needed on factors that may upregulate cereulide production in a given food matrix and the environmental factors affecting it. As a contribution towards this direction, we adjusted the growth environment and measured the cereulide production by strains selected for diversity. The temperature range where cereulide is produced was narrower than that for growth for most of the producer strains. Most cereulide was by most strains produced at room temperature (20 - 23ºC). Exceptions to this were two faecal isolates which produced the same amount of cereulide from 23 ºC up until 39ºC. We also found that at 37º C the choice of growth media for cereulide production differed from that at the room temperature. The food composition and temperature may thus be a key for understanding cereulide production in foods as well as in the gut. We investigated the contents of [K+], [Na+] and amino acids of six growth media. Statistical evaluation indicated a significant positive correlation between the ratio [K+]:[Na+] and the production of cereulide, but only when the concentrations of glycine and [Na+] were constant. Of the amino acids only glycine correlated positively with high cereulide production. Glycine is used worldwide as food additive (E 640), flavor modifier, humectant, acidity regulator, and is permitted in the European Union countries, with no regulatory quantitative limitation, in most types of foods. B. subtilis group members are endospore-forming bacteria ubiquitous in the environment, similar to B. cereus in this respect. Bacillus species other than B. cereus have only sporadically been identified as causative agents of food-borne illnesses. We found (Paper IV) that food-borne isolates of B. subtilis and B. mojavensis produced amylosin. It is possible that amylosin was the agent responsible for the food-borne illness, since no other toxic substance was found in the strains. This is the first report on amylosin production by strains isolated from food. We found that the temperature requirement for amylosin production was higher for the B. subtilis strain F 2564/96, a mesophilic producer, than for B. mojavensis strains eela 2293 and B 31, psychrotolerant producers. We also found that an atmosphere with low oxygen did not prevent the production of amylosin. Ready-to-eat foods packaged in micro-aerophilic atmosphere and/or stored at temperatures above 10 °C, may thus pose a risk when toxigenic strains of B. subtilis or B. mojavensis are present.
  • Honkasalo, Julia (Helsingin yliopisto, 2006)
    Epistemological foundationalism has for centuries attempted to unify all scientific inquiry into the context of one grand science, the first philosophy. One of the most important tasks of this tradition has been to ground all knowledge on absolutely certain foundations. In this master s thesis I ask the following question: To what extent and under what conditions is it possible to achieve absolute certainty in the sense of the attempts of Cartesian foundationalism? By examining how the 20th century philosophers, Edmund Husserl (1859-1938), Hannah Arendt (1906-1975) and Maurice Merleau-Ponty (1908-1961) interpret the epistemological methodology of René Descartes, I claim that the Cartesian achievement of absolute certainty rests on the implicit presupposition of an epistemologically prior form of faith in the world and trust (pistis) in other conscious beings. I show that knowledge is possible only within the context of a common world that is inhabited by several conscious beings that share a common linguistic system. This threefold element is shown to be the bedrock condition for any kind of philosophical inquiry. The main literature sources for this thesis are The Life of the Mind by Hannah Arendt, Le Visible et l invisible by Maurice Merleau-Ponty, Meditationes de Prima Philosophiae by René Descartes and Erfahrung und Urteil by Edmund Husserl.
  • Kirjavainen, Mirja (Helsingin yliopisto, 2010)
    Class II division 1 malocclusion occurs in 3.5 to 13 percent of 7 12 year-old children. It is the most common reason for orthodontic treatment in Finland. Correction is most commonly performed using headgear treatment. The aim of this study was to investigate the effects of cervical headgear treatment on dentition, facial skeletal and soft tissue growth, and upper airway structure, in children. 65 schoolchildren, 36 boys and 29 girls were studied. At the onset of treatment a mean age was 9.3 (range 6.6 12.4) years. All the children were consequently referred to an orthodontist because of Class II division 1 malocclusion. The included children had protrusive maxilla and an overjet of more than 2mm (3 to 11 mm). The children were treated with a Kloehn-type cervical headgear as the only appliance until Class I first molar relationships were achieved. The essential features of the headgear were cervical strong pulling forces, a long upward bent outer bow, and an expanded inner bow. Dental casts and lateral and posteroanterior cephalograms were taken before and after the treatment. The results were compared to a historical, cross-sectional Finnish cohort or to historical, age- and sex-matched normal Class I controls. The Class I first molar relationships were achieved in all the treated children. The mean treatment time was 1.7 (range 0.3-3.1) years. Phase 2 treatments were needed in 52% of the children, most often because of excess overjet or overbite. The treatment decreased maxillary protrusion by inhibiting alveolar forward growth, while the rest of the maxilla and mandible followed normal growth. The palate rotated anteriorly downward. The expansion of the inner bow of the headgear induced widening of the maxilla, nasal cavity, and the upper and lower dental arches. Class II malocclusion was associated with narrower oro- and hypopharyngeal space than in the Class I normal controls. The treatment increased the retropalatal airway space, while the rest of the airway remained unaffected. The facial profile improved esthetically, while the facial convexity decreased. Facial soft tissues masked the facial skeletal convexity, and the soft tissue changes were smaller than skeletal changes. In conclusion, the headgear treatment with the expanded inner bow may be used as an easy and simple method for Class II correction in growing children.
  • Metso, Tiina (Helsingin yliopisto, 2013)
    Cervicocerebral artery dissection (CeAD) is one of the leading causes of ischemic stroke in the young and middle-aged adults. The pathophysiology of CeAD is poorly understood. CeAD patients probably have a constitutional, partly genetic weakness of the vessel wall, which predisposes to tears in the connective tissue within the vascular wall in occurrence of environmental triggers of the disease, such as acute infection, migraine, or minor trauma. For this thesis project, we collected a register of all consecutive CeAD patients treated at the Helsinki University Central Hospital, Finland, between 1994 and 2008. In the first part of the thesis, we studied 103 patients with intracranial artery dissections (IAD). IADs could be divided into 2 distinct groups: i) non-aneurysmatic IADs presenting without subarachnoid hemorrhage that are associated with favorable outcomes and safe anticoagulant therapy, and ii) aneurysmatic IADs, characterized by subarachnoid hemorrhage and poorer prognosis. Secondly, we evaluated characteristics, prognostic factors and vascular risk factors in 301 CeAD patients. We found association of CeAD with male sex, and possible association with smoking and migraine, especially migraine with aura. Stroke severity and recent infection were associated with poorer outcome. The three other publications for the thesis were part of the CADISP project (Cervical Artery Dissection and Ischemic Stroke Patients), an international consortium focusing on research on CeAD. For the clinical part of CADISP, 983 patients with CeAD, 658 patients with ischemic stroke due to causes other than dissection, and 1170 healthy control subjects were included in 8 countries and 18 centers. In the CADISP cohort, vascular risk factors were less frequent in CeAD patients compared with young patients with a non-CeAD ischemic stroke. In comparison with healthy controls, hypercholesterolemia, obesity, and overweight were less frequent in CeAD patients, whereas CeAD patients had more hypertension. This suggests that hypertension may be a risk factor for CeAD. Finally, migraine was more common in CeAD patients with stroke than in patients with ischemic stroke due to a cause other than CeAD. We detected no excess of ischemic strokes, specific arterial distribution or other clinical or prognostic features characteristic to migraineous CeAD patients compared to those without migraine.
  • Zhang, Liangying (1999)
    The recently continuing proliferation of regional Preferential Trade Agreements (PTAs) and the glowing trend of emerging tri-bloc (Europe, America, Asia) raise the concern that the regional trade arrangements may challenge the world trading system embodied in the General Agreement on Tariff and Trade (GATT) and World Trade Organisation (WTO). In response to this background, this thesis reviews both the old and new key theoretical contributions on PTAs. The emphasis is put on the new one, which addresses the direct effect of regional arrangement on multilateral process. Basic international trade theory and policy, terminology and background are provided at the beginning to facilitate reading. While the paper does not attempt to put normative judgement on PTAs, it does call for more effort on multilateral process in the conclusion. Among the old literature, this paper reviews the classical work of Viner. Viner had a doubt on the welfare improvement Customs Union by raising the concept of trade diversion and trade creation. His model implies that unambiguous gain can only be obtained when the partner countries are the sole source of import even in the initial equilibrium. Among the recent literature, this paper reviews the analyses from the viewpoint of 'new political economy' which view trade policy as being determined by lobbying of the concentrated interest groups. Two models, Grossman-Helpman's and Krishna's, are introduced. Grossman-Helpman's small union model, which takes a specific factor model with n+1 goods in a political economy framework, addresses the incentive for the government to conclude a Free Trade Area, and reaches conclusion that free trade agreement could more likely be reached when it affords enhanced protection. Krishna's Cournot oligopoly model uses a similar framework of Grossman and Helpman's, however examines further the direction relation between the regional arrangement and multilateral process besides the incentive, and concludes the trade-diversion incentive and harmful effect of regional trade agreement on multilateral trade liberalisation.
  • Joas, Markus (2014)
    The Finnish forest industries are going through heavy adjustments as especially the western world is moving towards a more digitalized model where the amount of paper and pulp consumed is diminishing. It is obvious that the whole industry is in need for new solutions. These new solutions and innovations can be found from the field of bioenergy. Finland is rich with forest-based raw material which can provide a long-term and local source of energy. In the future this will be of primary importance as the prices of the non-renewable energy sources will climb higher as the deposits of the fossil fuels dry up. The usage of the renewable energy sources are also very important in order to prevent the global climate change and to achieve the goals regulated for Finland in the Kyoto Protocol and the European RES-E directive. This Master’s Thesis takes a look at the current state and the future trends of the Finnish wood pellet industries. The domestic wood-based pellet industries are studied with a concise literature review and a SWOT analysis based on the earlier literature. The analysis is linked to the future expectations and current retailer perspectives with a survey conducted between June and October 2013. The sample consists of 39 low, medium and high sales volume wood pellet manufacturers and retailers whom mostly do only domestic pellet trading business. Most of the strengths of the domestic wood-based pellet industries are related to different kinds of ecological aspects or different kinds of raw material related issues. In the future especially the prices of the raw materials, prices of other energy sources and prices of the end-product will be in a crucial role. Most of the survey participants underlined the significance of the governmental acts concerning the future of the whole business in Finland: a favorable taxing policy and different subsidies can make Finland truly a greener economy but this have not happened yet, much due to the unfavorable domestic politics. According to the survey respondents, in the future the demand of wood-based pellet services, especially tailored and ready-to-use services from maintenance to deliveries are going to increase.
  • Hätönen, Katja (Helsingin yliopisto, 2014)
    Glycaemic response to carbohydrate-containing foods is a combination of glucose absorption, endogenous glucose production, and tissue glucose uptake. After a carbohydrate-containing meal, blood glucose rises, which stimulates insulin secretion. The different amount and type of carbohydrates influence postprandial glucose and insulin responses differently. The concept of the glycaemic index (GI) was developed to rank carbohydrates according to their effect on blood glucose levels. Food with a low GI value is considered beneficial in maintaining optimal blood glucose due to smaller incremental increase in blood glucose than food with a high GI value. Foods characterized by a low GI therefore have been found to induce benefits on several risk markers related to type 2 diabetes and cardiovascular disease. The concept of the GI was originally developed as a tool for individuals with diabetes in choosing the most beneficial carbohydrate-rich foods regarding blood glucose responses. To assess the extent to which eaten food raises insulin levels, the concept of the insulinaemic index (II) was launched. The calculation of II values is performed similarly to GI values. The concept of GI has been widely studied and debated in the scientific literature. The main aim of this thesis was to investigate the effect of methodological choices on measured glucose and insulin responses, especially on GI values. To achieve these goals, five different postprandial studies were conducted in healthy individuals and in individuals with impaired glucose tolerance. Capillary and venous blood samples were collected up to 2-3 h postprandially and the incremental area under the curve (IAUC), GIs, and IIs were calculated. In the first study, the effects of methodological choices on measured glycaemic response and GI values were determined. Comparisons were done between blood sampling type (capillary vs. venous blood samples), type of reference food (white bread vs. glucose solution), and how many times the reference food should be repeated. Results revealed that the variation was smaller when capillary samples were used, performing the reference food test twice is sufficient, and to achieve better accuracy the glucose solution should be used as the reference food. In the second study, the effects of coffee on postprandial glucose and insulin responses were determined. Coffee as such does not modify the glucose and insulin responses of a carbohydrate food. Coffee had no marked effect on GI values. In the third study, the effects of subjects physiological characteristics, namely glucose tolerance and overweight, on postprandial glucose and insulin responses were examined. Both overweight and impaired glucose tolerance increased glycaemic and insulinaemic responses to the tested meals and the reference food. As a consequence, physiological characteristics did not affect the measured GI values. In the fourth study, the effects of other macronutrients, namely fat and protein, on glycaemic responses to a starchy food were examined. Both fat and protein have an independent decreasing effect on glycaemia, and as a consequence, GI values diminished. Insulin responses to the meals were also measured. Adding protein to the mashed potato-based meals considerably enhanced insulin responses to the meal. In the fifth study, the effects of alcohol on postprandial glucose and insulin responses were determined. Alcohol was found to increase postprandial glucose and insulin responses, probably through acutely increased insulin resistance. In addition, high GI values were measured for both beer and non-alcoholic beer. This should be taken into account when GI databases are compiled for epidemiologic studies. In summary, several factors affect measured GI values, highlighting that different methodological choices should be carefully considered. The use of recent international standards, for measuring GI values is highly recommended, and GI values measured prior to the standard should be interpreted and utilized with caution. To increase the reliability of GI measurements in the future, GI should be measured in combination with II measurements.
  • Hakojärvi, Mikko (Helsingin yliopisto, 2015)
    Precision farming is a set of advanced technologies and cultivation practices that aim to enhance crop growing conditions in a site-specific manner. Current machinery offers many technical tools for such actions, but information about when and where it is necessary to use the developed machinery effectively is lacking. The use of crop models has been proposed to combine the effects of growing season conditions and field spatial properties. However, in a timely and spatially variable environment, which a field often is, much information about site-specific growing conditions should be available in order for an advanced crop model to reproduce the site-specific growth in a detailed manner. Unfortunately the information from fields has often been very limited, and insufficient for such purposes. Furthermore the set of precision farming tools and the number of growth factors that can be managed is limited. For describing maximal biomass accumulation, a simple crop model was introduced and evaluated in this thesis. The model is mechanistic, and it uses a minimal number of parameters that all are based on physics, chemistry or physiology. The model can be used for calculating the radiation or radiation and water limited biomass accumulation of a C3-crop. A field experiment equipped with continuous measurements was used for model establishment and after model establishment the model was evaluated with a field experiment with various radiation, nitrogen fertilization and precipitation conditions. In both the studies the crop model was found to produce the maximal biomass accumulation when parameter values measured in the experiment were used. The model was applied in a study evaluating the effects of selected site- and depth-specific soil properties on yield variation on three different clay soil fields located in southern Finland. In order to evaluate the effects of selected soil properties under various weather conditions a Monte Carlo method was used with the biomass accumulation model and generated precipitations. The yield variation was evaluated according to temporal mean biomass yield and temporal standard deviation of the biomass yield. For studying the use of the model in a spatial environment, the introduced biomass accumulation model was applied in a simulator built for simulating a fully automated crop farm. In addition, the use of continuous soil moisture measurements for measuring the crop water use and further for biomass accumulation was tested. According to the results, the crop model was capable of simulating the highest biomass accumulation of the crops used in the experiments. This was the case for all radiation-limited simulations and for most of the water-limited simulations. In a few cases the values of the observed soil properties were found to cause too low biomass accumulation in simulations but in such cases the problem was also present in the comparisons of observed soil properties and observed soil water content during the growing season. For future research with the model, the next phase will be to test the model use in precision farming-related decision making. The structure of the model enables its use with other C3-crops than small grain cereals. Therefore testing of the model with other C3-crops could be performed in future research.
  • Koskimies, Silka (1999)
    Socialarbetarna bemöts i dag av en allt ökande andel klienter av annan etnisk bakgrund. De sedvanliga arbetsmetoderna är denna nya situation inte alltid ändamålsenliga. Socialtarbete måste därför utveckla nya metoder för att bättre kunna ta i beaktande de nya behoven som uppkommer i detta multietniska samhälle. Avsikten med denna studie är att jämföra hur socialtarbete i England och Finland har bemött de nya klientgrupperna och hur servicen har utvecklats. Denna studie är en fall studie av socialtarbete i två lokala områden, nämligen stadsdelen Islington i London, England och Vanda stad i Finland. Studiematerialet består av tolv halvstrukturerade intervjuer med socialarbetare i både Islington och Vanda, och av dokument om politik och praktik i socialservicen. I studien har kvalitativa metoder använts och intervjumaterialet har analyserats genom "grounded theory", som har utvecklats av Strauss och Corbin (1990), och genom jämförande metoder (Miles & Huberman 1994). Det jämförande perspektivet utvecklades under studiens gång till att möjliggöra en förståelse och jämförelse av situationen i de två olika länderna. Utgångspunkten var att de två samhällena måste noggranna studeras för att omständigheterna för socialtarbete skall förstås. För det första jämfördes olika concept som används i de olika länderna, för det andra jämfördes situationen för de etniska minoriteterna i vardera landet och för det tredje användes teoretisk litteratur för analyserandet av studiematerialet. Den teoretiska ramen för studien byggdes i huvudsak upp av minoritets politiska ideologier (Ely & Denney 1989), teorier om etnisk identitet (Liebkind 1994, Hutnik 1991) och av teorin om multikulturell medvetenhet (Matinheikki-Kokko 1997). I studien analyserades både politiken och praktiken i socialservicebyråerna. Resultaten från studien visar att social servicen i de båda länderna strävar till att ta i beaktande olika etniska grupper. I Vanda är detta dock ännu i ett tidigt stadium. Vanda har baserat sin service på jämlikhetsprincipen, som betyder i Finska förhållanden att alla klienter ges likadan service. Detta har dock visat sig vara problematiskt eftersom servicen då ofta är baserad på majoritetsbehov och stöder inte alltid minoritetsgrupper. Effekten kan därför vara den motsatta, det vill säga "assimilatorisk". I Islington strävade social arbetarna också efter jämlikhet, men utgångspunkten vara mera pluralistisk genom att i servicen ta i beaktande kulturell bakgrund. I studien kom det också fram att politiken, som speciellt tar i beaktande etniska minoriteter, måste tydligt anges för hela personalen och klienterna. Politiken måste också tillämpas i praktiken. Detta betyder för det första att socialbyrån i sin helhet måste vara medveten om olika etniska gruppers behov och om ändamålsenliga tillvägagångssätt för att möta dessa behov. För det andra måste socialarbetarna själva vara medvetna om situationen för deras etniska minoritets klienter. Socialarbetarna kan inte lämnas ensamma med ansvaret att utveckla servicen. Socialbyrån måste stöda socialarbetarna genom att ge medel för utvecklingen av service i form av politiska ståndpunkter, träning för hela personalen i dessa frågor och återkommande diskussioner och handledning om de etniska minoriteternas situation i samhället.
  • Koskimies, Silka (1999)
    Social work is today faced with a bigger diversity in society and ethnically mixed client groups. Mainstream social work methods are not always enough to meet the needs of all these new client groups. Therefore, social work has to develop its practices to be able to meet the challenges of the multi-ethnic society. The aim of this study is to compare how social work in England and Finland has responded to its minority ethnic clients, what policies and practices are developed. The study is a case study of social work in two local areas, namely the London borough of Islington in England and the city of Vantaa in Finland. The study material consists of semi-structured interviews with twelve social workers from different social service departments in Islington and Vantaa and of policy and practice documents. The study is a qualitative study and the interview material is analysed by using grounded theory (Strauss & Corbin 1990) and comparative methodology (Miles & Huberman 1994). A comparative framework was developed firstly by comparing different concepts used in each country concerning social work and minority ethnic groups, secondly by examining the situation of the minority ethnic groups in each country and finally by using theoretical literature for analysing the study material. The theoretical framework was mainly developed by theories about minority political ideologies (Ely and Denney 1989), theories about ethnic identity (Liebkind 1992, Hutnik 1991) and by a multicultural awareness framework (Matinheikki-Kokko 1997). The results of the study show that both countries have developed some responses to take into account the needs of minority ethnic clients. However, in Vantaa the process has just recently started. In Vantaa the services are based on an equality principle, which means in Finnish conditions that all clients are given the same kind of services. This has shown to be problematic as the service are often based on majority needs, which does not support minority groups. The effects might be the opposite, that is assimilationist. In Islington the social workers strive also for equality, but the starting point is more pluralistic, as the social workers attempt to take into account cultural background when providing services. The study showed also the importance of a clearly stated policy, which particularly takes into account minority ethnic groups. The policy has to be clearly outlined for all staff and even for clients. To put policy into practice means that it has to be effectively implemented. This means firstly that the whole social service department has to be aware of the needs of minority ethnic groups and of adequate intervention strategies to meet the needs. Secondly, the social workers have to be aware of the situation of their minority ethnic clients. This means that the social workers cannot be left alone with the responsibility to improve services. The social service department has to support the social workers by providing them means to develop the services. This includes a clear policy statement, training for all staff and regular supervision and discussions in meetings about issues concerning minority ethnic groups.