886 resultados para Use of web-based educational resources


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This thesis examines the impact of foreign exchange rate volatility to the extent of use of foreign currency derivatives. Especially the focus is on the impacts of 2008 global financial crisis. The crisis increased risk level in the capital markets greatly. The change in the currency derivatives use is analyzed by comparing means between different periods and in addition, by linear regression that enables to analyze the explanatory power of the model. The research data consists of financial statements figures from fiscal years 2006-2011 published by firms operating in traditional Finnish industrial sectors. Volatilities of the chosen three currency pairs is calculated from the daily fixing rates of ECB. Based on the volatility the sample period is divided into three sub-periods. The results suggest that increased FX market volatility did not increase the use foreign currency derivatives. Furthermore, the increased foreign exchange rate volatility did not increase the power of linear regression model to estimate the use foreign currency derivatives compared to previous studies.

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This study examines the Magic Formula and ERP5 value strategies in the Finnish stocks markets. Magic Formula ranks stocks based on EV/EBIT and ROA and ERP5 based on EV/EBIT, ROA, P/B and five-year trailing ROA. The purpose of the study is to examine whether the value strategies can be used to generate excess returns over the market index. The data has been collected from the Datastream database for the sample period from May 1997 to May 2010 and consists of the companies listed on the main list of Helsinki Stock Exchange. This study confirms the findings of previous research that value premium exists in the Finnish stock markets and that systematic value strategies can be used to form portfolios that outperform the market index with lower volatility.

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Longitudinal surveys are increasingly used to collect event history data on person-specific processes such as transitions between labour market states. Surveybased event history data pose a number of challenges for statistical analysis. These challenges include survey errors due to sampling, non-response, attrition and measurement. This study deals with non-response, attrition and measurement errors in event history data and the bias caused by them in event history analysis. The study also discusses some choices faced by a researcher using longitudinal survey data for event history analysis and demonstrates their effects. These choices include, whether a design-based or a model-based approach is taken, which subset of data to use and, if a design-based approach is taken, which weights to use. The study takes advantage of the possibility to use combined longitudinal survey register data. The Finnish subset of European Community Household Panel (FI ECHP) survey for waves 1–5 were linked at person-level with longitudinal register data. Unemployment spells were used as study variables of interest. Lastly, a simulation study was conducted in order to assess the statistical properties of the Inverse Probability of Censoring Weighting (IPCW) method in a survey data context. The study shows how combined longitudinal survey register data can be used to analyse and compare the non-response and attrition processes, test the missingness mechanism type and estimate the size of bias due to non-response and attrition. In our empirical analysis, initial non-response turned out to be a more important source of bias than attrition. Reported unemployment spells were subject to seam effects, omissions, and, to a lesser extent, overreporting. The use of proxy interviews tended to cause spell omissions. An often-ignored phenomenon classification error in reported spell outcomes, was also found in the data. Neither the Missing At Random (MAR) assumption about non-response and attrition mechanisms, nor the classical assumptions about measurement errors, turned out to be valid. Both measurement errors in spell durations and spell outcomes were found to cause bias in estimates from event history models. Low measurement accuracy affected the estimates of baseline hazard most. The design-based estimates based on data from respondents to all waves of interest and weighted by the last wave weights displayed the largest bias. Using all the available data, including the spells by attriters until the time of attrition, helped to reduce attrition bias. Lastly, the simulation study showed that the IPCW correction to design weights reduces bias due to dependent censoring in design-based Kaplan-Meier and Cox proportional hazard model estimators. The study discusses implications of the results for survey organisations collecting event history data, researchers using surveys for event history analysis, and researchers who develop methods to correct for non-sampling biases in event history data.

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A high final brightness is desired in most paper and board products. This requires bleaching processes that are able to produce high-brightness pulps. Mechanical pulps are widely bleached for high brightness using alkaline hydrogen peroxide with traditional sodium hydroxide and sodium silicate as additives. With high doses however, peroxide bleaching causes high organic loads in the mill effluent and anionic trash carry-over to papermaking. To alleviate the problems that arise from the use of sodium-based additives in peroxide bleaching, interest in the use of alternative magnesium-based chemicals has increased. In this study, a new, technical high-purity magnesium hydroxide-based bleaching additive was evaluated on laboratory-scale, pilot-scale and mill-scale experiments and trials for its ability to produce a high brightness in peroxide bleaching without the known problems of sodium-based chemicals. The key findings of this study include: a high brightening potential of peroxide bleaching using the Mg(OH)2-based additive, significant reductions (40-70%) in all categories of environmental load, and cationic demand lowered by 60-70% in bleached pulp with no loss in strength properties or in sheet bulk. When used in TMP refiner bleaching, the Mg(OH)2-based additive resulted in savings in specific energy consumption and provided a good bleaching response.

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The purpose of this investigation was to evaluate the possibility to enhance certain qualities of facial prostheses. Polymethyl methacrylate is still being used as base mate¬rial or clip carrier material, but it is hard and heavy, and debonding of the silicone from the acrylic base material is a frequent problem. This thesis aims to evaluate the use of fiber-reinforced composite (FRC) as framework material for maxillofacial silicone prostheses. FRC has been used as reinforcement in removable and fixed partial dentures since the 1990s. This material is lightweight and can be fabricated to compress the margins of the prosthesis slightly, to keep it tightly against the skin during jaw movements and facial expressions. Additionally, the use of a thermochromic pigment, colorless in room temperature and red in a cold environment, was studied in order to evaluate the possibility of using this color changing pigment in facial prostheses to mimic the color change of facial skin in cold weather. The tensile bond strength between pre-impregnated, unidirectional FRC and maxillofacial silicone elastomer was studied. Three different bonding agents or primers were compared. Bond strength was improved by one of the primers and by roughening the surface. The effect of a skin compressing glass fiber-reinforced composite framework on facial skin blood flow was studied by using a face mask, constructed with a compression pad corresponding to the outer margin of a glass fiber-reinforced framework beam of a facial prosthesis. The skin blood flow of ten healthy volunteers, aged 23-25 years, was measured during touch, light, and moderate compression of the skin, by using laser Doppler imaging technique. None of the compressions showed any marked effects on local skin blood flow. There were no significant differences between blood flow during compression and at baseline. Maxillofacial silicone elastomer was colored intrinsically with conventional color pigments: a control group containing only conventional pigments was compared to two test groups with 0.2 wt% and 0.6 wt% thermochromic pigment added. The color of the material was measured with a spectrophotometer in room temperature and after storage in a freezer. The color stability of the maxillofacial silicone elastomer colored with thermo¬chromic pigment was evaluated by artificial aging. The color dif¬ference of the L* (lightness) and a* values (redness), comparing color after the samples were stored at room temperature and in a freezer (-19°C), was statistically significant for both 0.2 wt% and 0.6 wt% thermo¬chromic pigment groups. The differences in the b* values (yellowness) were statistically significant for the 0.6 wt% group. Exposure to ultraviolet (UV) radiation led to visually noticeable and statistically signifi¬cant color changes (ΔE) in all color values in both test groups. The specimens containing thermochromic pigment were very sensitive to UV radiation. In conclusion, a framework of fiber-reinforced composite can successfully be bonded to maxillofacial silicone elastomer, and a framework beam, compressing the facial skin, did not remarkably alter the skin blood flow on healthy, young adults. The thermochromic pigment showed color change in maxillofacial silicone elastomer. However, artificial aging showed that it was too sensitive to UV radiation to be used, as such, in maxillofacial prostheses.

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Long-term independent budget travel to countries far away has become increasingly common over the last few decades, and backpacking has now entered the tourism mainstream. Nowadays, backpackers are a very important segment of the global travel market. Backpacking is a type of tourism that involves a lot of information search activities. The Internet has become a major source of information as well as a platform for tourism business transactions. It allows travelers to gain information very effortlessly and to learn about tourist destinations and products directly from other travelers in the form of electronic word-of-mouth (eWOM). Social media has penetrated and changed the backpacker market, as now modern travelers can stay connected to people at home, read online recommendations, and organize and book their trips very independently. In order to create a wider understanding on modern-day backpackers and their information search and share behavior in the Web 2.0 era, this thesis examined contemporary backpackers and their use of social media as an information and communication platform. In order to achieve this goal, three sub-objectives were identified: 1. to describe contemporary backpacker tourism 2. to examine contemporary backpackers’ travel information search and share behavior 3. to explore the impacts of new information and communications technologies and Web 2.0 on backpacker tourism The empirical data was gathered with an online survey, thus the method of analysis was mainly quantitative, and a qualitative method was used for a brief analysis of open questions. The research included both descriptive and analytical approaches, as the goal was to describe modern-day backpackers, and to examine possible interdependencies between information search and share behavior and background variables. The interdependencies were tested for statistical significance with the help of five research hypotheses. The results suggested that backpackers no longer fall under the original backpacker definitions described some decades ago. Now, they are mainly short-term travelers, whose trips resemble more those of mainstream tourists. They use communication technologies very actively, and particularly social media. Traditional information sources, mainly guide books and recommendations from friends, are of great importance to them but also eWOM sources are widely used in travel decision making. The use of each source varies according to the stage of the trip. All in all, Web 2.0 and new ICTs have transformed the backpacker tourism industry in many ways. Although the experience has become less authentic in some travelers’ eyes, the backpacker culture is still recognizable.

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Hermostoon vaikuttavien lääkkeiden käyttö on yleistä iäkkäässä väestössä. Erityisen yleistä käyttö on pitkäaikaisessa laitoshoidossa asuvilla iäkkäillä. Hermostoon vaikuttavien lääkkeiden haittavaikutuksia on tutkittu paljon, ja useat hermostoon vaikuttavat lääkeaineryhmät on tunnistettu murtumien riskitekijöiksi. Aikaisemmin ei ole kuitenkaan tutkittu usean hermostoon vaikuttavan lääkkeen yhteiskäytön yhteyksiä murtuman riskiin 65 vuotta täyttäneillä. Väitöskirjatutkimuksessa havaittiin, että usean hermostoon vaikuttavan lääkeaineen yhtäaikainen käyttö oli hyvin yleistä Porin kaupunginsairaalan viidellä pitkäaikaisen laitoshoidon osastolla (n = 154) vuosien 2004 ja 2005 vaihteessa. Kolmasosa tutkituista käytti säännöllisesti kolmea tai useampaa hermostoon vaikuttavaa lääkettä samanaikaisesti. Kun huomioitiin myös tarvittaessa otettavat lääkkeet, vastaava luku oli 53 %. Tutkimuksessa havaittiin myös viitteitä lääkkeiden epäasianmukaisesta käytöstä, kun potilaiden käyttämiä lääkkeitä verrattiin heidän kognitiiviseen ja fyysiseen suorituskyynsä sekä asetettuihin diagnooseihin. Liedon kunnassa 1990-luvulla toteutettuun väestöpohjaiseen Liedon Iäkkäät -seurantatutkimukseen osallistui 1177 lietolaista 65 vuotta täyttänyttä. Lääkitystietoja sekä seuranta-aikana tapahtuneita murtumia analysoimalla havaittiin, että kahden tai useamman bentsodiatsepiinin sekä kahden tai useamman psykoosilääkkeen käyttö oli yhteydessä murtuman riskiin 65 vuotta täyttäneillä miehillä. Opioidin ja psykoosilääkkeen yhteiskäyttö sekä opioidin ja bentsodiatsepiinin yhteiskäyttö oli yhteydessä iäkkäiden miesten murtuman riskiin. Naisilla vastaavia tilastollisesti merkitseviä yhteyksiä ei havaittu. Väitöskirjatutkimuksen uusin osa-aineisto perustui Porissa vuosina 2009–2010 toteutetun Satauni-tutkimuksen aineistoon. Tutkimuksessa osoitettiin 89 potilaan aineistossa, että hallittu, yhden kuukauden aikana lääkärin ja hoitajan tuella toteutettu bentsodiatsepiinivieroitus paransi merkitsevästi 55 vuotta täyttäneiden naisten käden puristusvoimaa kuuden kuukauden seuranta-aikana. Vastaavaa yhteyttä ei havaittu miehillä. Bentsodiatsepiinivieroituksella ei ollut yhteyttä osallistujien tasapainotestin tulosten paranemiseen kuuden kuukauden seurantaaikana. Murtumilla on vakavia seurauksia sekä yksilötasolla että yhteiskunnallisesti iäkkäässä väestössä. Murtumien ehkäisy on hyvin tärkeää. Siinä tulee kiinnittää huomiota potilaan käyttämään lääkitykseen ja arvioida erityisesti usean hermostoon vaikuttavan lääkkeen yhteiskäytön tarpeellisuutta.

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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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Context: Web services have been gaining popularity due to the success of service oriented architecture and cloud computing. Web services offer tremendous opportunity for service developers to publish their services and applications over the boundaries of the organization or company. However, to fully exploit these opportunities it is necessary to find efficient discovery mechanism thus, Web services discovering mechanism has attracted a considerable attention in Semantic Web research, however, there have been no literature surveys that systematically map the present research result thus overall impact of these research efforts and level of maturity of their results are still unclear. This thesis aims at providing an overview of the current state of research into Web services discovering mechanism using systematic mapping. The work is based on the papers published 2004 to 2013, and attempts to elaborate various aspects of the analyzed literature including classifying them in terms of the architecture, frameworks and methods used for web services discovery mechanism. Objective: The objective if this work is to summarize the current knowledge that is available as regards to Web service discovery mechanisms as well as to systematically identify and analyze the current published research works in order to identify different approaches presented. Method: A systematic mapping study has been employed to assess the various Web Services discovery approaches presented in the literature. Systematic mapping studies are useful for categorizing and summarizing the level of maturity research area. Results: The result indicates that there are numerous approaches that are consistently being researched and published in this field. In terms of where these researches are published, conferences are major contributing publishing arena as 48% of the selected papers were conference published papers illustrating the level of maturity of the research topic. Additionally selected 52 papers are categorized into two broad segments namely functional and non-functional based approaches taking into consideration architectural aspects and information retrieval approaches, semantic matching, syntactic matching, behavior based matching as well as QOS and other constraints.

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Positroniemissiotomografia (PET) on kajoamaton kuvantamismenetelmä, jolla voidaan tutkia biologisia ja farmakologisia prosesseja elävissä ihmisissä ja eläimissä. PET käyttää biologisesti aktiivisia yhdisteitä, joihin on liitetty lyhytikäinen positroni (β+) säteilijä, kuten 18F. Lääketieteellinen fluorikemia perustuu luonnonyhdisteiden tai niiden johdosten fluoraukseen, vaikka luonnonyhdisteissä fluori onkin harvinainen. Fluorin hapetuskyky on korkea, mikä johtaa helposti lämpöä vapauttaviin radikaaliketjureaktioihin ja epätoivottujen sivutuotteiden muodostumiseen. Alkuaine fluorin voimakkaasta reaktiivisuudesta johtuen elektrofiilisessa radiofluorauksessa saavutetaan usein huono paikkaselektiivisyys ja matala saanto. Tästä johtuen elektrofiilisessa radiofluorauksessa on tavoitteena kehittää helpommin käsiteltäviä ja vähemmän reaktiivisia elektrofiilisen fluorin lähteitä, joilla saavutetaan myös parempi paikkaselektiivisyys radiofluorauksessa. [18F]F2:n johdokset, [18F]Selectfluor bis(triflaatti) ([18F]SF) ja [18F]ClF, tehtiin korkealla ominaisaktiivisuudella ja niitä käytettiin malliyhdisteiden elektrofiilisessa synteesissä. Kaksi 6-[18F]FDOPA:n lähtöainetta, tina- ja booriesteriyhdiste, leimattiin käyttäen [18F]SF:a. [18F]NS12137, norepinefriinin kuljettajaproteiini (NET) -selektiivinen PET-merkkiaine, fluorattiin käyttäen kahta elektrofiilista fluorauslähtöainetta, [18F]SF ja [18F]F2, sekä nukleofiilista synteesimenetelmää. [18F]ClF:lle

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Neuron-specific enolase (NSE) is a glycolytic enzyme present almost exclusively in neurons and neuroendocrine cells. NSE levels in cerebrospinal fluid (CSF) are assumed to be useful to estimate neuronal injury and clinical outcome of patients with serious clinical manifestations such as those observed in stroke, head injury, anoxic encephalopathy, encephalitis, brain metastasis, and status epilepticus. We compared levels of NSE in serum (sNSE) and in CSF (cNSE) among four groups: patients with meningitis (N = 11), patients with encephalic injuries associated with impairment of consciousness (ENC, N = 7), patients with neurocysticercosis (N = 25), and normal subjects (N = 8). Albumin was determined in serum and CSF samples, and the albumin quotient was used to estimate blood-brain barrier permeability. The Glasgow Coma Scale score was calculated at the time of lumbar puncture and the Glasgow Outcome Scale (GOS) score was calculated at the time of patient discharge or death. The ENC group had significantly higher cNSE (P = 0.01) and albumin quotient (P = 0.005), but not sNSE (P = 0.14), levels than the other groups (Kruskal-Wallis test). Patients with lower GOS scores had higher cNSE levels (P = 0.035) than patients with favorable outcomes. Our findings indicate that sNSE is not sensitive enough to detect neuronal damage, but cNSE seems to be reliable for assessing patients with considerable neurological insult and cases with adverse outcome. However, one should be cautious about estimating the severity of neurological status as well as outcome based exclusively on cNSE in a single patient.

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Repowering existing power plants by replacing coal with biomass might offer an interesting option to ease the transition from fossil fuels to renewable energy sources and promote a fur-ther expansion of bioenergy in Europe, on account of the potential to decrease greenhouse gas emissions, as well as other pollutants (SOx, NOx, etcetera). In addition, a great part of the appeal of repowering projects comes from the opportunity to reuse the vast existing invest-ment and infrastructure associated with coal-based power generation. Even so, only a limited number of experiences with repowering are found. Therefore, efforts are required to produce technical and scientific evidence to determine whether said technology might be considered feasible for its adoption within European conditions. A detailed evaluation of the technical and economic aspects of this technology constitutes a powerful tool for decision makers to define the energy future for Europe. To better illustrate this concept, a case study is analyzed. A Slovakian pulverized coal plant was used as the basis for determining the effects on perfor-mance, operation, maintenance and cost when fuel is shifted to biomass. It was found that biomass fuel properties play a crucial role in plant repowering. Furthermore, results demon-strate that this technology offers renewable energy with low pollutant emissions at the cost of reduced capacity, relatively high levelized cost of electricity and sometimes, a maintenance-intensive operation. Lastly, regardless of the fact that existing equipment can be reutilized for the most part, extensive additions/modifications may be required to ensure a safe operation and an acceptable performance.

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The application of pulp and paper mill (PPM) sludge in agriculture and forestry has been acknowledged as soil amendments and a plant nutrient source. The main objectives of this study were to evaluate the total cost of the use of recycled nutrients from PPM sludge in fast growing pulpwood production, and the financial profitability of fast growing pulpwood production with the use of these recycled nutrients. The investment and production costs of fast growing pulpwood plantation were directly acquired from a previous research, while the other data was compiled through different studies. The total cost of the use of PPM sludge was evaluated based on assumed factors. Discounted cash flow method was used to evaluate the financial profitability, using NPV and IRR as indicators. The results of estimated sludge nutrient contents were 16.2 g N, 2.9 g P, and 2.4 g K kg-1 of dry sludge. The sludge application rate was estimated at 1.36 Mg/ha in the first year. The total cost of the use of PPM sludge involved transport and spreading cost of US$49.15/dry ton. The fertilization cost applied in the financial model was designed in 3 different options and their results were as follows: option (1) was taken directly from the reference research (US$97/ha); option (2) was the use of sludge alone (US$66.75/ha); and option (3) was the use of sludge and TSP fertilizer (US$83.80/ha). The average NPV without discounting was US$248,180 while the IRRs ranged between approximately 3-4% with an average of 3.63%. Although option (2) and (3) contributed to higher IRRs compared to option (1), this increase was still not significant as the IRR was not sensitive to the total fertilization cost. The advantages are that this practice can be performed at a lower cost and the application rate can be still increased if necessary. It is better for forest plantations compared to agriculture and consequently supports reforestation program. In addition, it can be similarly applied in wood biomass production. A disadvantage is that the IRRs were not very favorable compared to the criterion of 11%. The sludge high in C:N ratio can cause nitrogen immobilization, and regulatory concerns may restrict and complicate the use of sludge landspreading and contribute to additional costs and processes.

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The present study proposes to apply magnitude-squared coherence (MSC) to the somatosensory evoked potential for identifying the maximum driving response band. EEG signals, leads [Fpz'-Cz'] and [C3'-C4'], were collected from two groups of normal volunteers, stimulated at the rate of 4.91 (G1: 26 volunteers) and 5.13 Hz (G2: 18 volunteers). About 1400 stimuli were applied to the right tibial nerve at the motor threshold level. After applying the anti-aliasing filter, the signals were digitized and then further low-pass filtered (200 Hz, 6th order Butterworth and zero-phase). Based on the rejection of the null hypothesis of response absence (MSC(f) > 0.0060 with 500 epochs and the level of significance set at a = 0.05), the beta and gamma bands, 15-66 Hz, were identified as the maximum driving response band. Taking both leads together ("logical-OR detector", with a false-alarm rate of a = 0.05, and hence a = 0.0253 for each derivation), the detection exceeded 70% for all multiples of the stimulation frequency within this range. Similar performance was achieved for MSC of both leads but at 15, 25, 35, and 40 Hz. Moreover, the response was detected in [C3'-C4'] at 35.9 Hz and in [Fpz'-Cz'] at 46.2 Hz for all members of G2. Using the "logical-OR detector" procedure, the response was detected at the 7th multiple of the stimulation frequency for the series as a whole (considering both groups). Based on these findings, the MSC technique may be used for monitoring purposes.