11 resultados para general studies
em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland
Resumo:
The study examines international cooperation in product development in software development organisations. The software industry is known for its global nature and knowledge-intensity, which makes it an interesting setting to examine international cooperation in. Software development processes are increasingly distributed worldwide, but for small or even medium-sized enterprises, typical for the software industry, such distribution of operations is often possible only in association with crossing the company’s boundaries. The strategic decision-making of companies is likely to be affected by the characteristics of the industry, and this includes decisions about cooperation or sourcing. The objective of this thesis is to provide a holistic view on factors affecting decisions about offshore sourcing in software development. Offshore sourcing refers to a cooperative mode of offshoring, where a firm does not establish its own presence in a foreign country, but utilises a local supplier. The study examines product development activities that are distributed across organisational and geographical boundaries. The objective can be divided into two subtopics: general reasons for international cooperation in product development and particular reasons for cooperation between Finnish and Russian companies. The focus is on the strategic rationale at the company level, in particular in small and medium-sized enterprises. The theoretical discourse of the study builds upon the literature on international cooperation and networking, with particular focus on cooperation with foreign suppliers and within product development activities. The resource-based view is also discussed, as heterogeneity and interdependency of the resources possessed by different firms are seen as factors motivating international cooperation. Strategically, sourcing can be used to access resources possessed by an industrial network, to enhance the product development of a firm, or to optimise its cost structure. In order to investigate the issues raised by the theoretical review, two empirical studies on international cooperation in software product development have been conducted. The emphasis of the empirical part of the study is on cooperation between Finnish and Russian companies. The data has been gathered through four case studies on Finnish software development organisations and four case studies on Russian offshore suppliers. Based on the material from the case studies, a framework clarifying and grouping the factors that influence offshore sourcing decisions has been built. The findings indicate that decisions regarding offshore sourcing in software development are far more complex than generally assumed. The framework provides a holistic view on factors affecting decisions about offshore sourcing in software development, capturing the multidimensionality of motives for entering offshore cooperation. Four groups of factors emerged from the data: A) strategy-related aspects, B) aspects related to resources and capabilities, C) organisation-related aspects, and D) aspects related to the entrepreneur or management. By developing a holistic framework of decision factors, the research offers in-depth theoreticalunderstanding of offshore sourcing rationale in product development. From the managerial point of view, the proposed framework sums up the issues that a firm should pay attention to when contemplating product development cooperation with foreign suppliers. Understanding different components of sourcing decisions can lead to improved preconditions for strategising and engaging in offshore cooperation. A thorough decisionmaking process should consider all the possible benefits and risks of product development cooperation carefully.
Resumo:
The dissertation is based on four articles dealing with recalcitrant lignin water purification. Lignin, a complicated substance and recalcitrant to most treatment technologies, inhibits seriously pulp and paper industry waste management. Therefore, lignin is studied, using WO as a process method for its degradation. A special attention is paid to the improvement in biodegradability and the reduction of lignin content, since they have special importance for any following biological treatment. In most cases wet oxidation is not used as a complete ' mineralization method but as a pre treatment in order to eliminate toxic components and to reduce the high level of organics produced. The combination of wet oxidation with a biological treatment can be a good option due to its effectiveness and its relatively low technology cost. The literature part gives an overview of Advanced Oxidation Processes (AOPs). A hot oxidation process, wet oxidation (WO), is investigated in detail and is the AOP process used in the research. The background and main principles of wet oxidation, its industrial applications, the combination of wet oxidation with other water treatment technologies, principal reactions in WO, and key aspects of modelling and reaction kinetics are presented. There is also given a wood composition and lignin characterization (chemical composition, structure and origin), lignin containing waters, lignin degradation and reuse possibilities, and purification practices for lignin containing waters. The aim of the research was to investigate the effect of the operating conditions of WO, such as temperature, partial pressure of oxygen, pH and initial concentration of wastewater, on the efficiency, and to enhance the process and estimate optimal conditions for WO of recalcitrant lignin waters. Two different waters are studied (a lignin water model solution and debarking water from paper industry) to give as appropriate conditions as possible. Due to the great importance of re using and minimizing the residues of industries, further research is carried out using residual ash of an Estonian power plant as a catalyst in wet oxidation of lignin-containing water. Developing a kinetic model that includes in the prediction such parameters as TOC gives the opportunity to estimate the amount of emerging inorganic substances (degradation rate of waste) and not only the decrease of COD and BOD. The degradation target compound, lignin is included into the model through its COD value (CODligning). Such a kinetic model can be valuable in developing WO treatment processes for lignin containing waters, or other wastewaters containing one or more target compounds. In the first article, wet oxidation of "pure" lignin water was investigated as a model case with the aim of degrading lignin and enhancing water biodegradability. The experiments were performed at various temperatures (110 -190°C), partial oxygen pressures (0.5 -1.5 MPa) and pH (5, 9 and 12). The experiments showed that increasing the temperature notably improved the processes efficiency. 75% lignin reduction was detected at the lowest temperature tested and lignin removal improved to 100% at 190°C. The effect of temperature on the COD removal rate was lower, but clearly detectable. 53% of organics were oxidized at 190°C. The effect of pH occurred mostly on lignin removal. Increasing the pH enhanced the lignin removal efficiency from 60% to nearly 100%. A good biodegradability ratio (over 0.5) was generally achieved. The aim of the second article was to develop a mathematical model for "pure" lignin wet oxidation using lumped characteristics of water (COD, BOD, TOC) and lignin concentration. The model agreed well with the experimental data (R2 = 0.93 at pH 5 and 12) and concentration changes during wet oxidation followed adequately the experimental results. The model also showed correctly the trend of biodegradability (BOD/COD) changes. In the third article, the purpose of the research was to estimate optimal conditions for wet oxidation (WO) of debarking water from the paper industry. The WO experiments were' performed at various temperatures, partial oxygen pressures and pH. The experiments showed that lignin degradation and organics removal are affected remarkably by temperature and pH. 78-97% lignin reduction was detected at different WO conditions. Initial pH 12 caused faster removal of tannins/lignin content; but initial pH 5 was more effective for removal of total organics, represented by COD and TOC. Most of the decrease in organic substances concentrations occurred in the first 60 minutes. The aim of the fourth article was to compare the behaviour of two reaction kinetic models, based on experiments of wet oxidation of industrial debarking water under different conditions. The simpler model took into account only the changes in COD, BOD and TOC; the advanced model was similar to the model used in the second article. Comparing the results of the models, the second model was found to be more suitable for describing the kinetics of wet oxidation of debarking water. The significance of the reactions involved was compared on the basis of the model: for instance, lignin degraded first to other chemically oxidizable compounds rather than directly to biodegradable products. Catalytic wet oxidation of lignin containing waters is briefly presented at the end of the dissertation. Two completely different catalysts were used: a commercial Pt catalyst and waste power plant ash. CWO showed good performance using 1 g/L of residual ash gave lignin removal of 86% and COD removal of 39% at 150°C (a lower temperature and pressure than with WO). It was noted that the ash catalyst caused a remarkable removal rate for lignin degradation already during the pre heating for `zero' time, 58% of lignin was degraded. In general, wet oxidation is not recommended for use as a complete mineralization method, but as a pre treatment phase to eliminate toxic or difficultly biodegradable components and to reduce the high level of organics. Biological treatment is an appropriate post treatment method since easily biodegradable organic matter remains after the WO process. The combination of wet oxidation with subsequent biological treatment can be an effective option for the treatment of lignin containing waters.
Resumo:
The purpose of this study is to deepen the understanding of the meaning of ownership in the context of small and medium sized businesses. The research on ownership has increased and widened during the last few years. Ownership is treated increasingly as a psychological phenomenon and it has been noticed that it is common for SME ownermanagers to be mentally linked to their firms. Previous research is suggesting that the central role of an owner-manager in an SME is specifying the concept of SMEs, and that ownership is creating a great heterogeneity within SMEs. This study suggests that there is a variation whitin ownership behaviour of small business owners, and the variation is not totally random or irrational, but following the general patterns of business ownership and of doing business on an SME level. This study is a concept analytical in nature and it builds on the theoretical clarification of the concept of ownership. The theoretical consideration concludes with proposing a definition of ownership: Ownership means a subject’s relatively sustaining position of control in regard to an object. The empirical part of this study consists of five articles, out of which one is conceptual and four are empirical in nature. The notion of contextuality of ownership and the notions of SME characteristics form the basic premise of this study and the theoretical basis for the publications. From the owner-managers point of view, ownership relates the owner also to his or her environment and therefore also to the valuations of the owner-managers. This means that all the dimensions are not equally valued, but certain dimensions in his or her ownership are more important. The presented empirical research is supporting the claim that there is a variation whitin ownership behaviour of small business owners. When bringing the definition of ownership onto a personal and psychological level and into the SME context, it was noticed that ownership is not only a closed system phenomenon occurring between the owner and object owned, but it is also elementarily connected to the environment. Ownership - along with the psychological side of it - is a contextual phenomenon where the fundamental factor is the relatively sustaining position of control with regard to an object. As a contribution of the study, this definition is bringing a new point of view to the discussion on SMEs, SME strategic behaviour and family businesses. The study concludes with pointing out directions for future research.
Resumo:
In this Thesis the interaction of an electromagnetic field and matter is studied from various aspects in the general framework of cold atoms. Our subjects cover a wide spectrum of phenomena ranging from semiclassical few-level models to fully quantum mechanical interaction with structured reservoirs leading to non-Markovian open quantum system dynamics. Within closed quantum systems, we propose a selective method to manipulate the motional state of atoms in a time-dependent double-well potential and interpret the method in terms of adiabatic processes. Also, we derive a simple wave-packet model, based on distributions of generalized eigenstates, explaining the finite visibility of interference in overlapping continuous-wave atom lasers. In the context of open quantum systems, we develop an unraveling of non-Markovian dynamics in terms of piecewise deterministic quantum jump processes confined in the Hilbert space of the reduced system - the non-Markovian quantum jump method. As examples, we apply it for simple 2- and 3-level systems interacting with a structured reservoir. Also, in the context of ion-cavity QED we study the entanglement generation based on collective Dicke modes in experimentally realistic conditions including photonic losses and an atomic spontaneous decay.
Resumo:
Modern cancer therapy has resulted in increased survival among patients diagnosed with cancer at a young age. These improvements have led to the investigation of late morbidity and mortality associated with cancer and its treatments. The aim of this study was to evaluate late effects of cancer treated at a young age on the health of patients and their offspring. Utilising the nationwide population-based registries in Finland, we evaluated the risk of hypothyroidism and the probability of parenthood in cancer survivors as well as preterm birth, neonatal outcomes, and the risk of cancer among offspring of patients. The survivor cohort, identified from the Finnish Cancer Registry, consisted of 25,784 cancer patients diag-nosed between ages 0 and 34 in 1953–2004. By linkage to the population register, siblings of these patients were identified for comparison. The prevalence of hypothyroidism was higher among former childhood cancer (aged 0–16) patients than in the general population. The probability of parenthood following early onset cancer was overall significantly reduced compared to siblings. Offspring of female cancer survivors were at an increased risk of preterm birth, this risk being highest among patients diagnosed in childhood and early adulthood (aged 20–34 years). The offspring were not, however, at a significantly increased risk of neonatal death or stillbirth, though they were more likely to need monitoring or intensive care in the neonatal period. The risk of sporadic cancer among offspring of male and female cancer survivors was not elevated in comparison to the general population. The study showed that former cancer patients are at risk of certain adverse endocrine and reproductive health outcomes and should be followed for timely intervention. The offspring of cancer survivors do not appear to be at risk for adverse health outcomes.
Resumo:
Neuromuscular blocking agents (NMBAs) are widely used in clinical anaesthesia and emergency medicine. Main objectives are to facilitate endotracheal intubation and to allow surgery by reducing muscle tone and eliminating sudden movements, which may otherwise lead to trauma and complications. The most commonly used NMBAs are non-depolarizing agents with a medium duration of action, such as rocuronium and cisatracurium. They bind to the acetylcholine receptors in the neuromuscular junction, thus inhibiting the depolarization of the postsynaptic (muscular) membrane, which is a prerequisite for muscle contraction to take place. Previously, it has been assumed that nitrous oxide (N2O), which is commonly used in combination with volatile or intravenous anaesthetics during general anaesthesia, has no effect on NMBAs. Several studies have since claimed that N2O in fact does increase the effect of NMBAs when using bolus administration of the relaxant. The effect of N2O on the infusion requirements of two NMBAs (rocuronium and cisatracurium) with completely different molecular structure and pharmacological properties was assessed. A closed-loop feedback controlled infusion of NMBA with duration of at least 90 minutes at a 90% level of neuromuscular block was used. All patients received total intravenous anaesthesia (TIVA) with propofol and remifentanil. In both studies the study group (n=35) received N2O/Oxygen and the control group (n=35) Air/Oxygen. There were no significant differences in the mean steady state infusion requirements of NMBA (rocuronium in Study I; cisatracurium in Study II) between the groups in either study. In Study III the duration of the unsafe period of recovery after reversal of rocuronium-induced neuromuscular block by using neostigmine or sugammadex as a reversal agent was analyzed. The unsafe period of recovery was defined as the time elapsed from the moment of no clinical (visual) fade in the train-of-four (TOF) sequence until an objectively measured TOF-ratio of 0.90 was achieved. The duration of these periods were 10.3 ± 5.5 and 0.3 ± 0.3 min after neostigmine and sugammadex, respectively (P < 0.001). Study IV investigated the possible effect of reversal of a rocuronium NMB by sugammadex on depth of anaesthesia as indicated by the bispectral index and entropy levels in thirty patients. Sugammadex did not affect the level of anaesthesia as determined by EEG-derived indices of anaesthetic depth such as the bispectral index and entropy.
Resumo:
The aim of this thesis research was to gain a better understanding of the emplacement of rapakivi granite intrusions, as well as the emplacement of gold-bearing hydrothermal fluids in structurally controlled mineralizations. Based on investigations of the magnetic fabric, the internal structures could be analysed and the intrusion mechanisms for rapakivi granite intrusions and respectively different deformation stages within gold-bearing shear and fault zones identified. Aeromagnetic images revealed circular structures within the rapakivi granite batholiths of Wiborg, Vehmaa and Åland. These circular structures represent intrusions that eventually build up these large batholiths. The rapakivi granite intrusions of Vehmaa, Ruotsinpyhtää within the Wiborg batholith and Saltvik intrusions within the Åland batholith all show bimodal magnetic susceptibilities with paramagnetic and ferromagnetic components. The distribution of the bimodality is related to different magma batches of the studied intrusions. The anisotropy of magnetic susceptibility (AMS) reveals internal structures that cannot be studied macroscopically or by microscope. The Ruotsinpyhtää and Vehmaa intrusions represent similar intrusion geometries, with gently to moderately outward dipping magnetic foliations. In the case of Vehmaa, the magnetic lineations are gently plunging and trend in the directions of the slightly elongated intrusion. The magnetic lineations represent magma flow. The shapes of the AMS ellipsoids are also more planar (oblate) in the central part of the intrusion, whereas they become more linear (prolate) near the margin. These AMS results, together with field observations, indicate that the main intrusion mechanism has involved the subsidence of older blocks with successive intrusion of fractionated magma during repeated cauldron subsidence. The Saltvik area within the Åland batholith consists of a number of smaller elliptical intrusions of different rapakivi types forming a multiple intrusive complex. The magnetic fabric shows a general westward dipping of the pyterlite and eastward dipping of the contiguous even-grained rapakivi granite, which indicates a central inflow of magma batches towards the east and west resulting from a laccolitic emplacement of magma batches, while the main mechanism for space creation was derived from subsidence. The magnetic fabric of structurally controlled gold potential shear and fault zones in Jokisivu, Satulinmäki and Koijärvi was investigated in order to describe the internal structures and define the deformation history and emplacement of hydrothermal fluids. A further aim of the research was to combine AMS studies with palaeomagnetic methods to constrain the timing for the shearing event relative to the precipitation of ferromagnetic minerals and gold. All of the studied formations are dominated by monoclinic pyrrhotite. The AMS directions generally follow the tectonic structures within the formations. However, internal variations in the AMS direction as well as the shapes of the AMS ellipsoids are observed within the shear zones. In Jokisivu and Satulinmäki in particular, the magnetic signatures of the shear zone core differ from the margins. Furthermore, the shape of the magnetic fabric in the shear zone core of Jokisivu is dominated by oblate shapes, whereas the margins exhibit prolate shapes. These variations indicate a later effect of the hydrothermal fluids on the general shear event. The palaeo-magnetic results reveal a deflection from the original Svecofennian age geomagnetic direction. These results, coupled with correlations between the orientation of the NRM vectors and the magnetic and rock fabrics, imply that the gold-rich hydrothermal fluids were emplaced pre/syntectonically during the late stages of the Svecofennian orogeny.
Resumo:
Background: Approximately 11,000 revascularization procedures, either percutaneous coronary interventions (PCI) or coronary artery bypass grafting surgery (CABG), are performed yearly in Finland for coronary artery disease. Periprocedural risk factors for mortality and morbidity as well as long-term outcome have been extensively studied in general populations undergoing revascularization. Treatment choice between PCI and CABG in many high risk groups and risk-stratification, however, needs clarification and there is still room for improvement in periprocedural outcomes. Materials and methods: Cohorts of patients from Finnish hospitals revascularized between 2001 and 2011 were retrospectively analyzed. Patient records were reviewed for baseline variables and postprocedural outcomes (stroke, myocardial infarction, quality of life measured by the EQ-5D –questionnaire, repeat revascularization, bleeding episodes). Data on date and mode of death was acquired from Statistics Finland. Statistical analysis was performed to identify predictors of adverse events and compare procedures. Results: Postoperative administration of blood products (red blood cells, fresh frozen plasma, platelets) after isolated CABG independently and dose-dependently increases the risk of stroke. Patients 80 years or older who underwent CABG had better survival at 5 years compared to those who underwent PCI. After adjusting for baseline differences survival was similar. Patients on oral anticoagulation (OAC) for atrial fibrillation (AF) treated with CABG had better survival and overall outcome at 3 years compared to PCI patients. There was no difference in incidence of stroke or bleeding episodes. Differences in outcome remained significant after adjusting for propensity score. Lower health-related quality of life (HRQOL) scores as measured by the visual analogue scale (VAS) of the EQ-5D questionnaire at 6 months after CABG predicted later major adverse cardiac and cerebrovascular events (MACCE). Deteriorating function and VAS scores between 0 and 6 months on the EQ-5D also independently predicted later MACCE. Conclusions: Administration of blood products can increase the risk of stroke after CABG and liberal use of transfusions should be avoided. In the frail subpopulations of patients on OAC and octogenarians CABG appears to offer superior long-term outcome as compared to PCI. Deteriorating HRQOL scores predict later adverse events after CABG. Keywords: percutaneous coronary intervention, coronary artery bypass grafting, age over 80, transfusion, anticoagulants, coronary artery disease, health-related quality of life, outcome.
Resumo:
The cosmological standard view is based on the assumptions of homogeneity, isotropy and general relativistic gravitational interaction. These alone are not sufficient for describing the current cosmological observations of accelerated expansion of space. Although general relativity is extremely accurately tested to describe the local gravitational phenomena, there is a strong demand for modifying either the energy content of the universe or the gravitational interaction itself to account for the accelerated expansion. By adding a non-luminous matter component and a constant energy component with negative pressure, the observations can be explained with general relativity. Gravitation, cosmological models and their observational phenomenology are discussed in this thesis. Several classes of dark energy models that are motivated by theories outside the standard formulation of physics were studied with emphasis on the observational interpretation. All the cosmological models that seek to explain the cosmological observations, must also conform to the local phenomena. This poses stringent conditions for the physically viable cosmological models. Predictions from a supergravity quintessence model was compared to Supernova 1a data and several metric gravity models were studied with local experimental results. Polytropic stellar configurations of solar, white dwarf and neutron stars were numerically studied with modified gravity models. The main interest was to study the spacetime around the stars. The results shed light on the viability of the studied cosmological models.
Resumo:
Aino Toiviainen Probiotics and oral health: in vitro and clinical studies University of Turku, Faculty of Medicine, Institute of Dentistry, Periodontology, Finnish Doctoral Program in Oral Sciences (FINDOS-Turku), Turku, Finland Annales Universitatis Turkuensis, Sarja – Ser. D, Medica-Odontologica. Painosalama Oy, Turku, Finland, 2015 Probiotics are used, for example, to prevent and treat diarrhea, allergies and respiratory infections, and there is an increasing interest to use probiotics also for oral health purposes. The most commonly used probiotic bacteria are lactobacilli and bifidobacteria, which are acidogenic and aciduric. From the oral point of view, use of these probiotics may, at least in theory, mean an increased risk of caries. In this thesis, the effects of probiotics on oral microbial composition, acid production of dental plaque and gingival health were studied through in vitro studies and two clinical studies. In a randomized, double-blind and crossover study, 13 healthy adults were allocated into two groups. Half of the subjects first consumed Lactobacillus rhamnosus GG tablets twice a day for two weeks, and after the washout period, L. reuteri tablets twice a day for two weeks. The other half of the subjects used the tablets in reverse order. In another controlled, randomized and double-blind study, 62 healthy adults were allocated into two groups. One group used the test tablets containing L. rhamnosus GG and B. lactis BB-12 and the other group used control tablets without probiotics. The recommendation for the use of the tablets was 4 per day for 4 weeks. Probiotic lactobacilli interfered with S. mutans biofilm formation and the adhesion of S. mutans to saliva-coated hydroxyapatite in vitro. No effect was found in S. mutans levels in the three-species biofilms. In clinical studies, the studied probiotics had no effect on the acid production of plaque. The counts of mutans streptococci and the oral microbial composition remained the same. Tablets containing L. rhamnosus GG and Bifidobacterium animalis subsp. lactis BB-12 did decrease the amount of plaque and gingival bleeding. According to our results, it seems that probiotics have beneficial effects on gingival health. The present results confirmed that probiotics are safe and have beneficial effects on oral health. Since the consumption of probiotics by the general population is steadily increasing, an understanding of the functions of probiotics in the oral cavity has become more important. Keywords: lactobacilli, bifidobacteria, caries, periodontal disease, mutans streptococci, probiotics
Resumo:
The non-idealities in a rotor-bearing system may cause undesirable subcritical superharmonic resonances that occur when the rotating speed of the rotor is a fraction of the natural frequency of the system. These resonances arise partly from the non-idealities of the bearings. This study introduces a novel simulation approach that can be used to study the superharmonic vibrations of rotor-bearing systems. The superharmonic vibrations of complex rotor-bearing systems can be studied in an accurate manner by combining a detailed rotor and bearing model in a multibody simulation approach. The research looks at the theoretical background of multibody formulations that can be used in the dynamic analysis of flexible rotors. The multibody formulations currently in use are suitable for linear deformation analysis only. However, nonlinear formulation may arise in high-speed rotor dynamics applications due to the cenrrifugal stiffening effect. For this reason, finite element formulations that can describe nonlinear deformation are also introduced in this work. The description of the elastic forces in the absolute nodal coordinate formulation is studied and improved. A ball bearing model that includes localized and distributed defects is developed in this study. This bearing model could be used in rotor dynamics or multibody code as an interface elements between the rotor and the supporting structure. The model includes descriptions of the nonlinear Hertzian contact deformation and the elastohydrodynamic fluid film. The simulation approaches and models developed here are applied in the analysis of two example rotor-bearing systems. The first example is an electric motor supported by two ball bearings and the second is a roller test rig that consists of the tube roll of a paper machine supported by a hard-bearing-type balanceing machine. The simulation results are compared to the results available in literature as well as to those obtained by measuring the existing structure. In both practical examples, the comparison shows that the simulation model is capable of predicting the realistic responses of a rotor system. The simulation approaches developed in this work can be used in the analysis of the superharmonic vibrations of general rotor-bearing systems.