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  • Wan, Minli (2009)
    China's primary wood processing industry and wood consuming sectors have experienced rapid growth in recent years. Industries like sawnwood and plywood have developed very quickly. The purpose of this study is to: 1) provide an overview of the demand, supply, imports and exports of raw wood and primary wood products in the China market between 1993 and 2007, 2) present quantitative estimates of the relative importance of factors influencing the demand, supply and exports of Chinese plywood, 3) draw conclusions about China's potentials and challenges for foreign enterprises, including Finnish companies. The information, analyses and findings presented in this study can give a reference for wood processing companies, especially for sawnwood and plywood firms, and governmental agencies in China. In addition, the study provides a basis for further study and research. Even though much information has been published in China, academic research in the Chinese woodworking market is scarce, and especially, time-series data is missing and unreliable. This study tries to fill this gap. It is based on secondary data collected from various sources, including literatures, journals, magazines, consulting reports, industry analysis, news, and so on. The annual time-series data obtained for variables in models are mainly gathered from original official Chinese sources. The study increases the information and understanding on the Chinese wood products markets by using descriptive and explanatory methods to analyze the data for background information, markets and empirical modeling. By employing econometric models, based on the elasticity estimates, Chinese plywood demand seems to be income elastic but price inelastic, Chinese plywood supply would be highly elastic with raw material price but scale inelastic, and Chinese plywood exports appear to be highly income elastic.
  • Dinku, Zerihun Megersa (2014)
    Coronal magnetic field governs most of the coronal activities. Despite of its importance in solar atmosphere, there is no accurate method of measuring the coronal magnetic field. The current measurement methods of coronal magnetic fields depend on extrapolation of photospheric magnetic fields. There are different models to study the global structure of coronal magnetic field. The most commonly used models are PFSS model and magnetohydrodynamic (MHD) model. In this thesis, we study the coronal magnetic field condition during major solar energetic particle (SEP) event of 23rd solar cycle by using the PFSS model. We use 114 SEP events observed by the SOHO/ERNE experiment in 1996-2010. In the beginning we identified 43 events that are relatively free from the disturbance caused by interplanetary coronal mass ejections (ICMEs). We examined these SEP events using IDL software developed by Lockheed Martin Solar and Astrophysics Lab (LMSAL). We produced plots of open coronal magnetic field of each events using SolarSoft. We also classified SEP events according to their number of connection points as events with; single connection point, double connection points and multiple connection points. Events with multiple connection points make up almost one third of the total events. These events show that the coronal magnetic connection are typically complicated and neighboring magnetic field lines in the solar wind can be magnetically connected to regions that are well separated in the low corona. We also found that the actual connection longitude (a longitude that takes in to account the coronal magnetic field) is most of the time is closer to the flare site associated with the event than the Parker spiral connection longitude. The Parker spiral longitudes, connection longitudes and flare longitudes are analyzed in detail by histograms. Finally, we chose two example events and analyzed them by using intensity-time profile of particles, plots of from LASCO CME catalog and plots produce by the SolarSoft. Based on our analysis we classified the example events into gradual and hybrid SEP events.
  • Brilhante, Virginia (2013)
    This thesis presents a workflow for analysis of exome sequencing data aiming at identification of single nucleotide variants (SNVs) causing recessively inherited mitochondrial disease in children. Several variant selection criteria that are consistent with such group of genetic disorders are applied along the workflow in relation to mode of inheritance, allele frequency and the Finnish ancestry of the patients. These are combined with knowledge of nuclear-encoded mitochondrial proteins and prediction of pathogenic variants, narrowing down the total set of SNVs found in a patient to those most likely to be causative. Patient exomes are analysed individually (n=1 studies). The bioinformatic resources used for implementation include public and in-house databases of mitochondrial nuclear genes, human genetic variation and exome controls, as well as software tools for prediction of pathogenic SNVs and mitochondria-targeting proteins. Exome variant data from a cohort of 49 molecularly undiagnosed children were analysed through the workflow, leading to the identification of mitochondrial disease-causing SNVs located in nuclear genes for 10 of the patients. Therefore, a success rate of 20% was achieved. The workflow has been an important element in the use of exome sequencing as a new research tool at the Wartiovaara group of the Research Program for Molecular Neurology, Faculty of Medicine, University of Helsinki.
  • Brilhante, Virginia (2013)
    This thesis presents a workflow for analysis of exome sequencing data aiming at identification of single nucleotide variants (SNVs) causing recessively inherited mitochondrial disease in children. Several variant selection criteria that are consistent with such group of genetic disorders are applied along the workflow in relation to mode of inheritance, allele frequency and the Finnish ancestry of the patients. These are combined with knowledge of nuclear-encoded mitochondrial proteins and prediction of pathogenic variants, narrowing down the total set of SNVs found in a patient to those most likely to be causative. Patient exomes are analysed individually (n=1 studies). The bioinformatic resources used for implementation include public and in-house databases of mitochondrial nuclear genes, human genetic variation and exome controls, as well as software tools for prediction of pathogenic SNVs and mitochondria-targeting proteins. Exome variant data from a cohort of 49 molecularly undiagnosed children were analysed through the workflow, leading to the identification of mitochondrial disease-causing SNVs located in nuclear genes for 10 of the patients. Therefore, a success rate of 20% was achieved. The workflow has been an important element in the use of exome sequencing as a new research tool at the Wartiovaara group of the Research Program for Molecular Neurology, Faculty of Medicine, University of Helsinki.
  • Brilhante, Virginia (2013)
    This thesis presents a workflow for analysis of exome sequencing data aiming at identification of single nucleotide variants (SNVs) causing recessively inherited mitochondrial disease in children. Several variant selection criteria that are consistent with such group of genetic disorders are applied along the workflow in relation to mode of inheritance, allele frequency and the Finnish ancestry of the patients. These are combined with knowledge of nuclear-encoded mitochondrial proteins and prediction of pathogenic variants, narrowing down the total set of SNVs found in a patient to those most likely to be causative. Patient exomes are analysed individually (n=1 studies). The bioinformatic resources used for implementation include public and in-house databases of mitochondrial nuclear genes, human genetic variation and exome controls, as well as software tools for prediction of pathogenic SNVs and mitochondria-targeting proteins. Exome variant data from a cohort of 49 molecularly undiagnosed children were analysed through the workflow, leading to the identification of mitochondrial disease-causing SNVs located in nuclear genes for 10 of the patients. Therefore, a success rate of 20% was achieved. The workflow has been an important element in the use of exome sequencing as a new research tool at the Wartiovaara group of the Research Program for Molecular Neurology, Faculty of Medicine, University of Helsinki.
  • Xu, Yuan (2013)
    The increasing recognition of eco-friendly packaging in the packaging industry makes paperboard one of the most promising green packaging materials. The global demand for paperboard has increased rapidly in the past two decades. The purposes of the study are: firstly, to provide an overview of the consumption, production, imports and exports of paperboard products in different regions worldwide between 1992 and 2010. Secondly, as the Finnish paperboard industry has been highly export-oriented, the study also aims to provide quantitative analysis of the main determinants influencing the demand for Finnish paperboard exports in its main destinations-Germany and Russia by applying economic models from the first quarter of 1995 to the third quarter of 2011. Finally, trends projection for the future development of Finnish paperboard is presented based on results of analysis. The research is both descriptive and explanatory based on secondary data collected from various databases. The regional analysis of paperboard market from 1992 to 2010 revealed that North America and Western Europe’s paperboard production exceeded the consumption, where Asia, Eastern Europe and Latin America’s consumption exceeded the production. The consumption and production growth was extremely fast in Asia and it has been the largest consumer and producer of paperboard products since 2000s. Western Europe has been the largest exporter and importer throughout the years. The empirical modeling of Finnish paperboard export demand showed that the export demand for Finnish paperboard in Germany was highly affected by the total paperboard imports of Germany and its GDP. It also has high sensitivity to the income changes of Germany in long term, but the price effect was not significant. The export demand for Finnish paperboard in Russia has low income elasticity and the price effect was statistically significant. Oil price has also significant influence on Finnish paperboard export demand to Russia. According to the linear trends projection for Finnish paperboard market to 2020, the consumption and imports will grow very slowly or even stagnate, but the production and exports will continuously increase at a faster pace.
  • Järvinen, Ilpo (Helsingin yliopisto, 2006)
    Wireless access is expected to play a crucial role in the future of the Internet. The demands of the wireless environment are not always compatible with the assumptions that were made on the era of the wired links. At the same time, new services that take advantage of the advances in many areas of technology are invented. These services include delivery of mass media like television and radio, Internet phone calls, and video conferencing. The network must be able to deliver these services with acceptable performance and quality to the end user. This thesis presents an experimental study to measure the performance of bulk data TCP transfers, streaming audio flows, and HTTP transfers which compete the limited bandwidth of the GPRS/UMTS-like wireless link. The wireless link characteristics are modeled with a wireless network emulator. We analyze how different competing workload types behave with regular TPC and how the active queue management, the Differentiated services (DiffServ), and a combination of TCP enhancements affect the performance and the quality of service. We test on four link types including an error-free link and the links with different Automatic Repeat reQuest (ARQ) persistency. The analysis consists of comparing the resulting performance in different configurations based on defined metrics. We observed that DiffServ and Random Early Detection (RED) with Explicit Congestion Notification (ECN) are useful, and in some conditions necessary, for quality of service and fairness because a long queuing delay and congestion related packet losses cause problems without DiffServ and RED. However, we observed situations, where there is still room for significant improvements if the link-level is aware of the quality of service. Only very error-prone link diminishes the benefits to nil. The combination of TCP enhancements improves performance. These include initial window of four, Control Block Interdependence (CBI) and Forward RTO recovery (F-RTO). The initial window of four helps a later starting TCP flow to start faster but generates congestion under some conditions. CBI prevents slow-start overshoot and balances slow start in the presence of error drops, and F-RTO reduces unnecessary retransmissions successfully.
  • Luukkainen, Pekka (2003)
    Sydän- ja verisuonitaudit nousivat teollisuusmaissa suurimmaksi julkisen terveydenhuollon ongelmaksi 1940-luvulla, tartuntatautien hävittyä lääketieteen kehityksen seurauksena. Suomi saavutti jopa kyseenalaista kunniaa 1950- ja 1960-luvuilla korkeimmilla mitatuilla sydän- ja verisuonitautikuolleisuusluvuilla maailmassa. Kuolleisuudessa on kuitenkin havaittu selviä alueellisia eroja, ja varsinkin Itä-Suomi on kärsinyt erittäin korkeasta sydän- ja verisuonitautikuolleisuudesta. Useissa tutkimuksissa on todettu kohonneen verenpaineen, korkean kolesterolin, ylipainon ja tupakoinnin olevan tärkeimpiä sydän- ja verisuonitautien riskitekijöitä. Näihin tekijöihin yksilö voi kuitenkin helposti vaikuttaa muokkaamalla elintapojaan ja ruokavaliotaan. Tässä tutkielmassa on seurattu vuodesta 1959 lähtien kahta vuosina 1900-1919 syntyneiden miesten kohorttia Itä- ja Länsi-Suomesta. Tarkoituksena oli selvittää eroja alueiden kuolleisuudessa ja riskitekijöiden kehityksessä kilpailevien kuolinsyiden näkökulmasta käyttäen Coxin verrannollisten hasardien mallia. Tutkimuksen kuluessa huomattiin sydän- ja verisuonitautikuolleisuuden alueellisten erojen vähentyneen, sekä kolesterolin ja tupakoinnin olevan merkittävimpiä riskitekijöitä ikääntyneiden ihmisten joukossa.
  • Luukkainen, Pekka (2003)
    Cardiovascular diseases became the leading public health problem in the developed countries in the late 1940s. Finland has obtained questionable fame for having even the highest coronary heart disease mortality in the world. Previous studies have shown that there are clear regional differencies in mortality due to cardiovascular diseases, especially eastern Finland has suffered from exeptionally high cardiovascular disease mortality. Elevated blood pressure, high total cholesterol, obesity and smoking are suggested to be the main risk factors for the cardiovascular diseases. These factors could be easily affected by making changes in the way of life and dietary habits. In this thesis, we studied two cohorts consisting men born between 1900-1919 from east and west Finland. Cohorts have been examined since year 195$ The aim was to clarify the differensies in the mortality between the cohorts and in the risk factor levels by using competing risks. Data was analysed with Cox's proportional hazards model. During the follow-up study, differensies between the cohorts in mortality due to cardiovascular diseases diminished. According to this study the main risk factors for aging population are high total cholesterol and smoking.
  • Döhla, Julia Maria (2013)
    Peroxisome proliferator activated receptor γ coactivator 1α (PGC-1α) is a transcriptional coactivator involved in mitochondrial biogenesis, oxidative stress response, and energy metabolism. PGC-1α is part of an energy sensing network that translates environmental influences into alterations in gene expression of mainly mitochondrial molecular pathways. A role in neuroprotection has been implicated for PGC-1α in the context of mitochondrial expression networks. Our research group has previously established a transgenic mouse line with stable overexpression of PGC-1α in brain neurons. Transgenic overexpression of PGC-1α is associated with an enhanced functional state of mitochondrial energy production. In the context of neurodegenerative processes, brain neurons of PGC-1α transgenic mice are protected against oxidative stressors in the MPTP mouse model of Parkinson’s Disease. To further characterize the transcriptional activity of PGC-1α regulated gene networks in brains of transgenic mice, a quantitative real-time PCR based system was established. Gene expression was measured for a subset of genes found to be differentially regulated in a microarray based screening of RNA obtained from hippocampus and cortex of PGC-1α transgenic mice. Increased PGC-1α gene expression was found in hippocampus and cortex of PGC-1α transgenic mice, and their translation into protein was confirmed immunohistochemically. Expression analysis revealed significant changes in mRNA levels of PGC-1α controlled molecular pathways involved in mitochondrial energy production and antioxidant responses. Furthermore, alterations in the expression of some non-mitochondrial genes with established links to neurodegeneration were observed. Furthermore, a change in GABAA receptor subunit expression was detected. In accordance with previous studies on the PGC-1α transgenic mouse line, these findings suggest that differential gene expression associated with PGC-1α overexpression contributes to an enhanced functional state of neurons in hippocampus and cortex of PGC-1α transgenic mice. Increased knowledge about the transcriptional modulation of neuronal genes regulated by PGC-1α can lead to better insights into mechanisms governing neurodegeneration and neuroprotective pathways. Pharmacological modulation of PGC-1α activity may be a feasible approach for neuroprotective treatments in neurodegenerative diseases, such as Parkinson’s Disease.
  • Suominen, Tina (Helsingin yliopisto, 2015)
    Neurotransmitters and neurosteroids are compounds that regulate the functions of the brain. The neurotransmitters dopamine (DA) and serotonin (5-HT) play a role in several psychological conditions, including schizophrenia, depression and anxiety. DA also has an important role in Parkinson s disease. Neurosteroids are involved in neurodegenerative diseases. In Alzheimer s disease and multiple sclerosis, the levels of neurosteroids are decreased in certain areas of the brain. Neurosteroids differ from classical neurotransmitters in that they are lipid-soluble and can easily cross the blood-brain barrier (BBB). Neurotransmission can be studied in vivo by microdialysis, and as the concentrations of neurotransmitters in the microdialysates are very low, sensitive analytical methods are needed for their analysis. In this work an UPLC-MS/MS method was developed for the determination of 5-HT, DA, their phase I metabolites 5-HIAA, DOPAC and HVA, and their sulfonate and glucuronide conjugates. The method was validated and applied for analyzing human brain microdialysis and cerebrospinal fluid (CSF) samples. Intact glucuronide and sulfate conjugates were identified and quantified for the first time in the human brain. The origin of the determined phase II metabolites in the brain is unknown. Even though sulfonate-conjugated compounds such as dopamine sulfonate (DA-S) and 5-HIAA-S were detected in the human brain, it is unclear whether they were locally formed or transported into the brain through the BBB from peripheral sources. The BBB permeation of DA-S was studied by administration of isotope (13C6)-labelled DA-S, which can be distinguished from endogenous DA-S by mass spectrometry, subcutaneously (s.c.) while brain microdialysis samples were collected and analyzed by UPLC-MS/MS. The fate of 13DA-S in brain was followed by monitoring 13C6-labelled DA-S metabolites and hydrolysis products. The results proved that DA-S permeates through the BBB, and indicated that DA-S finally either permeates through the BBB back to the peripheral circulation or is dissociated or metabolized by unknown mechanisms. While the hydrophilic neurotransmitters DA and 5-HT are well suited for analysis by liquid chromatography coupled to atmospheric pressure ionization, the neurosteroids have more commonly been analyzed by methods based on gas chromatography (GC) coupled to ionization in vacuum. Recently GC has been combined to atmospheric pressure photoionization utilizing heated nebulizer microchips (μAPPI). We now constructed a simpler interface for combining GC to mass spectrometry (MS) using dopant-assisted atmospheric pressure photoionization (APPI), utilizing commercially available hardware. The neurosteroids were analyzed as trimethylsilyl (TMS) derivatives, and the effect of different dopants (chlorobenzene, toluene and anisole) on the ionization and on the sensitivity of the method was investigated. Chlorobenzene was chosen as the best dopant, as the neurosteroid-TMS derivatives formed intense molecular ions with minimal fragmentation, while with toluene and anisole also protonated molecules were observed. The molecular ions of the steroids formed by APPI ionization showed fragmentation patterns in their MS/MS spectra similar to the patterns seen in corresponding spectra obtained by electron impact ionization (EI). Therefore the use of EI libraries could be possible, thus enabling the identification of a wide range of unknown compounds.
  • Selin, Markus (2012)
    This thesis is constructed as a part of a larger research project aiming to increase understanding of polyketone reductases (PKR) and develop applications from them. PKRs are enzymes in biosynthetic pathways leading to several aromatic secondary metabolites in plants. The previous work in the research group has led to establishment of several callus cultures from plants belonging to the genus Rubus in the family Rosaceae. The aim in the experimental part of this thesis is the identification and semi-quantitation of raspberry ketone (RK) and related aromatics in the cell suspension cultures initiated from the previously established callus cultures. RK is biosynthetically produced by reduction of p-hydroxybenzalacetone (p-OH-BA) by benzalacetone reductase (BAR). As a part of the experimental work, p-OH-BA has to be chemically synthetized and analysed. Special emphasis is placed to experiment, develop and validate an extraction method for phenolic compounds using ASE 200 working station. In the review part of this thesis, the basic procedures of chemical analysis are described, optimization and validation of analytical methods are discussed, and lastly studies related to raspberry ketone (RK) are summarized. The detection limit is 0.73 μg/ml for RK with the established UPLC-UV method, and the quantitation limit (QL) is 2.22 μg/ml. At the QL, the standard deviation of the extraction method is 8.9 % and the results are 6.4 % higher than expected. At the high end of the standard curve the extraction results are 18.7 % higher than expected. Some changes are proposed to optimize the method. Analysis of the cell line extracts with the established UPLC-UV method did not readily reveal any of the studied compounds. Although the interpretation of the results of the MS experiment is still underway, RK was detected from the arctic bramble cell line Ra15. Also, a possible derivative of zingerone was detected from cloudberry cell line extract even without the corresponding standard compound. This shows the power of the MS in metabolite profiling, and gives a course for future studies.
  • Islam, Hasan Mahmood Aminul (2013)
    The Web has introduced a new technology in a more distributed and collaborative form of communication, where the browser and the user replace the web server as the nexus of communications in a way that after the call establishment through web servers, the communication is performed directly between browsers as peer to peer fashion without intervention of the web servers. The goal of Real Time Collaboration on the World Wide Web (RTCWeb) project is to allow browsers to natively support voice, video, and gaming in interactive peer to peer communications and real time data collaboration. Several transport protocols such as TCP, UDP, RTP, SRTP, SCTP, DCCP presently exist for communication of media and non-media data. However, a single protocol alone can not meet all the requirements of RTCWeb. Moreover, the deployment of a new transport protocol experiences problems traversing middle boxes such as Network Address Translation (NAT) box, firewall. Nevertheless, the current implementation for transportation of non-media in the very first versions of RTCWeb data does not include any congestion control on the end-points. With media (i.e., audio, video) the amount of traffic can be determined and limited by the codec and profile used during communication, whereas RTCWeb user could generate as much as non-media data to create congestion on the networks. Therefore, a suitable transport protocol stack is required that will provide congestion control, NAT traversal solution, and authentication, integrity, and privacy of user data. This master’s thesis will give emphasis on the analysis of transport protocol stack for data channel in RTCWeb and selects Stream Control Transmission Protocol (SCTP), which is a reliable, message oriented general-purpose transport layer protocol, operating on top of both IPv4 and IPv6, providing congestion control similar to TCP and additionally, some new functionalities regarding security, multihoming, multistreaming, mobility, and partial reliability. However, due to the lack of universal availability of SCTP within the OS(s), it has been decided to use the SCTP userland implementation. WebKit is an open source web browser engine for rendering web pages used by Safari, Dashboard, Mail, and many other OS X applications. In WebKit RTCWeb implementation using GStreamer multimedia framework, RTP/UDP is utilized for the communication of media data and UDP tunnelling for non-media data. Therefore, in order to allow a smooth integration of the implementation within WebKit, we have decided to implement GStreamer plugins using SCTP userland stack.. This thesis work also investigates the way Mozilla has integrated those protocols in the browser’s network stack and how the Data Channel has been designed and implemented using SCTP userland stack.
  • Lizcano, Raymundo (2013)
    In the literature part an introduction to emerging organic contaminants is presented as well as the subcategory of endocrine disrupting chemicals, which includes steroid hormones. An overview of liquid chromatography trends in environmental analysis as well as mass spectrometry operational conditions are discussed. Review is focused on ionization techniques and tandem mass spectrometry functionalities reported on state of the art studies of steroidal compounds in environmental samples. Experimental part presents an extensive sample preparation method and a liquid chromatography – mass spectrometry (HPLC-MS) method that were developed for the determination of concentration of eleven steroidal compounds: 4-androstene-3,17-dione (A1), trans-androsterone (A2), Corticosterone (C1), Cortisone (C2), Estrone (E1), 17-β-estradiol (E2), Estriol (E3), 17-α-ethynil estradiol (EE2), Progesterone (P), 17-hydroxy progesterone (HP) and Testosterone (T). Separation efficiency and analysis time were compared for three HPLC columns with different stationary phase: Pentafluorophenyl (PFP), C8 and C18 monolithic. Three atmospheric pressure ionization (API) techniques were tested to compare their performance: Electrospray ionization (ESI), Atmospheric Pressure Chemical Ionization (APCI) and Atmospheric Pressure Photoionization (APPI). The proposed method included the best column choice coupled with the API technique, which presented an efficient ionization for most of the target analytes. Best methodology was applied to the analysis of effluent and influent samples from the wastewater treatment plant in Viikinmäki, Helsinki.
  • Talew, Eyob (2015)
    Solar Energetic particle (SEP) events are sudden and temporary increases in the cosmic ray fluxes which are related to solar flares or interplanetary shocks originating from the Sun. Solar energetic particle transport modelling requires a systematic understanding of the properties of the heliosphere. In the current modelling of particle transport in the heliosphere, it is assumed that the interplanetary medium has a steady-state solar wind and that the magnetic field in the heliosphere follows a Parker spiral. The presence of coronal mass ejections (CMEs) or interplanetary coronal mass ejections (ICMEs) in the heliosphere could cause interference with the solar wind and the magnetic field in the heliosphere. In this project we analyse two heliospheric modelling tools, called ENLIL and ENLIL-with-cone models, to see how accurately they could describe the heliosphere in the presence of Coronal mass ejections. To realize this goal we investigated the SEP events of the 23rd solar cycle. At first we investigated 114 SEP events recorded in this cycle for their relationships with CMEs and ICMEs. First, we investigated whether the SEP events could be related to ICME using time-window analysis and the position of the ICME when the SEP event was recorded. Using this process we identified 43 SEP events that are ICME-clean (not related to any ICME according to the two criteria we set). We then modelled the ICME-clean events using ENLIL modelling. We further analysed the ICME-clean events if they have any relation to CMEs. We narrowed our search only to SEP events that have three or less CME that could be associated with them. We then produced a plot for these SEP events to further study the relation between the SEP and the CMEs. We singled out the SEP event that was recorded on May 9, 1999 as a perfect candidate to be further analysed using ENLIL-with-cone model. This event is chosen because it is associated with a fast northward CME that expands into the western hemisphere and could possibly have accelerated the SEP towards Earth. When analysed with ENLIL-with-cone model, we found out that the CME interfered with the magnetic field lines that are directed towards Earth, thus providing a likely origin for the observed SEP event at 1AU. Though the contact between the CME and the Earthward field lines was very brief, it disrupted the Parker spiral structure of the magnetic field lines. From the statistical analysis of the ICMEs and CMEs during the large SEP events of the 23rd solar cycle, we deduced that the two assumptions used in the modelling of heliospheric SEP transport (steady-state solar wind and Parker spiral structure of the magnetic field) could not be made in typical cases. However, more advanced descriptions of the heliospheric field like ENLIL-with-cone could be utilized for modelling instead. From this project we concluded that a future heliospheric modelling tools need to encompass more factors than the two assumptions discussed above.
  • Kamlang-ek, Pimwalee (2012)
    The literature survey reviewed principles of oxidation of edible oils, adverse effects of lipid oxidation and analysis of volatile oxidation products by SPME-GC-MS. The main aim of the experimental research was to study the influence of relative humidity (RH) on the release of volatile oxidation products from spray-dried emulsions with natural and cross-linked casein as emulsifier. The release of volatiles was determined by SPME-GC-MS. The sub aims were to study the effects of stabilization time at specific RHs, of temperature and agitation speed during the SPME extraction. The spray-dried emulsions were oxidised at 40oC in order to reach a certain level of oxidation. Next, the powders were stabilised under five RHs (0%, 11%, 33%, 54% and 75%) for one or two weeks in order to observe the effect of the RH and the stabilisation time on the release of volatiles. After adjusting the RHs, volatile compounds were analysed by SPME-GC-MS. The following SPME extraction conditions were tested: C1: temperature 40oC, agitation speed 250 rpm, C2: 50oC, 250 rpm, C3: 40oC, 500 rpm and C4: 50oC, 500 rpm. Identification of the compounds was carried out by matching their MS spectra with the NIST database. Altogether 45 volatiles released from the powders could be identified, and 18 of them were found in most samples. RH had an important effect on the release of volatiles from the encapsulated samples. The highest release was always observed at 11% and 33% RH, whereas the lowest release was found at 0% and/or 75% RH, depending on the SPME extraction conditions. The stabilisation time did not have a significant effect on the release of volatiles in most RHs. During the SPME extraction step, elevation of the temperature from 40oC to 50oC, as well as the agitation speed from 250 rpm to 500 rpm, facilitated higher release. However, the effect of temperature was greater than that of agitation speed. Although it was suspected that cross-linking of sodium-caseinate would enhance retention of volatiles, our experiment showed greater peak areas of most volatiles from the cross-linked samples than from the natural ones. By controlling the SPME parameters, it was possible to obtain repeatable volatile compound results. The SPME-GC-MS method applied in this study can be reliably used to analyse volatile oxidation products from spray-dried emulsions. Only at very low or high RH the release of volatiles may differ from samples stored at 11% -54% RH.
  • Javanainen, Timo (2007)
    Market risk is among the most important sources of risk for companies in the financial and commodity markets. Proper estimation of market risk has become very important in the electricity market, where volatility is very high and trading volumes continue to increase. Value at Risk (VaR) is the most widely used approach to quantify market risk. The aim of this thesis is to study how well analytical VaR methods can be applied to trading portfolios of electricity derivatives. The objectives of the thesis are: 1. To study how the financial electricity market differs from the financial markets and other commodity markets, and what are the implications of these differences to the estimation of market risk 2. To study which analytical VaR methods provide the best results in the financial and commodity markets 3. To study how well these analytical VaR methods perform in estimating the daily market risk for portfolios of electricity derivatives and conclude the implications of this performance to the Nordic electricity market 4. To give recommendations on how the market risk of portfolios of electricity derivatives should be measured in the financial electricity market. Several studies show that due to the non-storability of electricity, the dynamics of the forward curve in financial electricity market differ from other commodity markets. Both the literature study and statistical analysis done in this thesis reveal that the return distributions of Nord Pool traded electricity forwards exhibit fat tails and are skewed. The non-normality of risk factor returns causes some challenges for VaR estimation. In this thesis, the most prominent analytical VaR methods are identified based on the literature study and assessed with a thorough backtesting procedure. The statistical analysis and backtesting conducted in this thesis are unique in terms of focus and scope. The results show that using the studied VaR methods in the Nordic electricity market underestimates market risk. Practical recommendations on using VaR methods are given to market participants. The MATLAB implementation done in connection to this thesis is of considerable extent and could be used by a small or medium size company to estimate its market risk.
  • Javanainen, Timo (2007)
    Markkinariski on merkittävä riskilähde finanssi- ja hyödykemarkkinoilla toimivilla yrityksillä. Markkinariskin estimoiminen riittävällä tarkkuudella on erittäin tärkeä asia sähkön johdannaismarkkinalla, jossa volatiliteetti on muihin markkinoihin verrattuna hyvin korkea ja kaupankäyntivolyymit jatkavat kasvamistaan. Value at Risk (VaR) on yleisimmin käytetty lähestymistapa markkinariskin kvantifioimiseksi. Tämän Pro gradu -työn tavoitteena on tutkia, kuinka hyvin ns. analyyttiset Value at Risk -menetelmät toimivat sähkön johdannaissalkkujen markkinariskin estimoimisessa. Työn tarkemmat tavoitteet ovat: 1. Tutkia, miten sähkön johdannaismarkkina eroaa finanssimarkkinoista ja muista hyödykemarkkinoista ja miten nämä eroavaisuudet vaikuttavat markkinariskin estimointiin sähkön johdannaismarkkinalla 2. Tutkia, mitkä analyyttiset VaR-menetelmät toimivat parhaiten finanssimarkkinoilla ja muilla hyödykemarkkinoilla markkinariskin estimoimisessa 3. Tutkia, kuinka hyvin analyyttiset VaR-menetelmät toimivat sähkön johdannaissalkun päivittäisen markkinariskin estimoimisessa, ja päätellä tulosten seuraamukset pohjoismaiselle sähkön johdannaismarkkinalle. 4. Antaa suosituksia siitä, miten markkinariskiä tulisi sähkön johdannaismarkkinalla estimoida. Sähkö eroaa muista hyödykkeistä siinä, että sähköä ei pystytä taloudellisesti järkevästi varastoimaan pitkiä aikoja. Useat aiemmat tutkimukset ovat osoittaneet, että todennäköisesti juuri sähkön varastoimattomuus on muovannut sähkön johdannaismarkkinan dynamiikan erilaiseksi kuin muiden hyödykemarkkinoiden dynamiikan. Tämän työn kirjallisuuskatsaus ja empiirinen osa osoittavat, että pohjoismaisen sähköpörssin finanssijohdannaisten tuottojakaumat ovat paksuhäntäisiä ja vinoja. Tämä riskifaktoreiden ei-normaalisuus aiheuttaa tiettyjä haasteita VaR-lukujen estimointiin. Tässä työssä identifioidaan kirjallisuuskatsauksen avulla lupaavimmat analyyttiset VaR-menetelmät ja menetelmiä verrataan toisiinsa ns. backtestauksella. Tässä työssä esitetyt backtesting-tulokset ja tilastollinen analyysi ovat sähkön johdannaismarkkinalla sekä toteutustavaltaan että laajuudeltaan uusia. Työn tulokset osoittavat, että käyttämällä työssä käsiteltyjä VaR-menetelmiä markkinatoimijat aliarvioivat markkinariskiä sähkön johdannaismarkkinalla. Tätä työtä varten rakennettu MATLAB-toteutus on laajuudeltaan mittava ja kelpaisi sinällään pienen- tai keskisuuren yrityksen markkinariskin estimoimiseen.
  • Saikku, Laura (Helsingin yliopisto, 2010)
    Industrial ecology is an important field of sustainability science. It can be applied to study environmental problems in a policy relevant manner. Industrial ecology uses ecosystem analogy; it aims at closing the loop of materials and substances and at the same time reducing resource consumption and environmental emissions. Emissions from human activities are related to human interference in material cycles. Carbon (C), nitrogen (N) and phosphorus (P) are essential elements for all living organisms, but in excess have negative environmental impacts, such as climate change (CO2, CH4 N2O), acidification (NOx) and eutrophication (N, P). Several indirect macro-level drivers affect emissions change. Population and affluence (GDP/capita) often act as upward drivers for emissions. Technology, as emissions per service used, and consumption, as economic intensity of use, may act as drivers resulting in a reduction in emissions. In addition, the development of country-specific emissions is affected by international trade. The aim of this study was to analyse changes in emissions as affected by macro-level drivers in different European case studies. ImPACT decomposition analysis (IPAT identity) was applied as a method in papers I III. The macro-level perspective was applied to evaluate CO2 emission reduction targets (paper II) and the sharing of greenhouse gas emission reduction targets (paper IV) in the European Union (EU27) up to the year 2020. Data for the study were mainly gathered from official statistics. In all cases, the results were discussed from an environmental policy perspective. The development of nitrogen oxide (NOx) emissions was analysed in the Finnish energy sector during a long time period, 1950 2003 (paper I). Finnish emissions of NOx began to decrease in the 1980s as the progress in technology in terms of NOx/energy curbed the impact of the growth in affluence and population. Carbon dioxide (CO2) emissions related to energy use during 1993 2004 (paper II) were analysed by country and region within the European Union. Considering energy-based CO2 emissions in the European Union, dematerialization and decarbonisation did occur, but not sufficiently to offset population growth and the rapidly increasing affluence during 1993 2004. The development of nitrogen and phosphorus load from aquaculture in relation to salmonid consumption in Finland during 1980 2007 was examined, including international trade in the analysis (paper III). A regional environmental issue, eutrophication of the Baltic Sea, and a marginal, yet locally important source of nutrients was used as a case. Nutrient emissions from Finnish aquaculture decreased from the 1990s onwards: although population, affluence and salmonid consumption steadily increased, aquaculture technology improved and the relative share of imported salmonids increased. According to the sustainability challenge in industrial ecology, the environmental impact of the growing population size and affluence should be compensated by improvements in technology (emissions/service used) and with dematerialisation. In the studied cases, the emission intensity of energy production could be lowered for NOx by cleaning the exhaust gases. Reorganization of the structure of energy production as well as technological innovations will be essential in lowering the emissions of both CO2 and NOx. Regarding the intensity of energy use, making the combustion of fuels more efficient and reducing energy use are essential. In reducing nutrient emissions from Finnish aquaculture to the Baltic Sea (paper III) through technology, limits of biological and physical properties of cultured fish, among others, will eventually be faced. Regarding consumption, salmonids are preferred to many other protein sources. Regarding trade, increasing the proportion of imports will outsource the impacts. Besides improving technology and dematerialization, other viewpoints may also be needed. Reducing the total amount of nutrients cycling in energy systems and eventually contributing to NOx emissions needs to be emphasized. Considering aquaculture emissions, nutrient cycles can be partly closed through using local fish as feed replacing imported feed. In particular, the reduction of CO2 emissions in the future is a very challenging task when considering the necessary rates of dematerialisation and decarbonisation (paper II). Climate change mitigation may have to focus on other greenhouse gases than CO2 and on the potential role of biomass as a carbon sink, among others. The global population is growing and scaling up the environmental impact. Population issues and growing affluence must be considered when discussing emission reductions. Climate policy has only very recently had an influence on emissions, and strong actions are now called for climate change mitigation. Environmental policies in general must cover all the regions related to production and impacts in order to avoid outsourcing of emissions and leakage effects. The macro-level drivers affecting changes in emissions can be identified with the ImPACT framework. Statistics for generally known macro-indicators are currently relatively well available for different countries, and the method is transparent. In the papers included in this study, a similar method was successfully applied in different types of case studies. Using transparent macro-level figures and a simple top-down approach are also appropriate in evaluating and setting international emission reduction targets, as demonstrated in papers II and IV. The projected rates of population and affluence growth are especially worth consideration in setting targets. However, sensitivities in calculations must be carefully acknowledged. In the basic form of the ImPACT model, the economic intensity of consumption and emission intensity of use are included. In seeking to examine consumption but also international trade in more detail, imports were included in paper III. This example demonstrates well how outsourcing of production influences domestic emissions. Country-specific production-based emissions have often been used in similar decomposition analyses. Nevertheless, trade-related issues must not be ignored.