Bakgrund: Längdskidåkning är en sport med hög förekomst av överbelastningsskador i ländryggen. Anledningarna till besvärens uppkomst har diskuterats frekvent och flera faktorer har setts spela in. Att variera träningen har setts vara viktigt, inte minst under uppväxten, för att undvika skador längre upp i åldrarna.  Syfte: Att undersöka förekomsten av upplevda ländryggsbesvär de senaste 12 månaderna hos elever på längdskidgymnasium i Sverige. Studien undersökte även skillnader i träningsminuter och träningsvariation under åldern 10–12 år mellan elever utan ländryggsbesvär och elever med lindriga–svåra ländryggsbesvär. Metod: En deskriptiv jämförande tvärsnittsstudie gjordes där 11 av Sveriges 12 längdskidgymnasium deltog. Antalet studiedeltagare var 147, vilket motsvarade en svarsfrekvens på 46%. Könsfördelningen var 52,4% kvinnor och 47,6% män. En webbenkät besvarades angående ländryggsbesvär de senaste 12 månaderna baserat på frågeformuläret Nordic Musculoskeletal Questionnaire (NMQ). Även frågor gällande träning under åldern 10–12 och ländryggsbesvär under längdskidåkning besvarades. Utifrån svaren delades deltagarna in i grupper baserade på besvärsgrad.  Resultat: Förekomsten av ländryggsbesvär senaste 12 månaderna var 50,3%. Det fanns inga signifikanta skillnader gällande träningsminuter under uppväxten mellan grupperna “ej besvär” och “måttliga-svåra besvär” respektive “ej besvär” och “besvär”. Slutsats: Studiens resultat kunde bekräfta en hög förekomst av ländryggsbesvär hos längdskidgymnasieelever. Inga skillnader sågs i träningen under uppväxten mellan de med respektive utan besvär. Fler faktorer spelar in och vidare studier krävs för att få klarhet i varför besvären uppstår i en så hög grad. / Background: Cross-country skiing have a high prevalence of overuse injuries mainly located at the lower back. Low back pain (LBP) is frequently discussed among cross-country skiers and several factors may cause the problem. A variation in training has been seen to be important, especially during childhood, to avoid overuse injuries in higher ages.  Objective: To investigate the prevalence of LBP for the past 12 months in Swedish high school students specialized at cross-country skiing. The study also investigated the differences in training minutes and the variation in training during age 10–12 years between students without LBP and students with mild to severe LBP. Method: A descriptive comparative cross-sectional study was made, 11 of the 12 cross-country ski high schools in Sweden participated. The response rate was 46% which corresponds 147 participants, 52,4% women and 47,6% men.  The participants answered a web survey with questions regarding LBP the last 12 months and training during childhood. Groups based on the severity of LBP was formed.  Results: The prevalence of LBP the last 12 months was 50,3%. There were no significant differences regarding training in the age of 10–12 years between the groups. Conclusion: The study confirms that the prevalence of LBP is high in high school students specialized at cross-country skiing. No differences were found regarding training during childhood between the groups. More factors may affect the problem and further research is needed.

<p>The overarching theme of this research is about environmental microplastic pollution, and how much various entities are willing to sacrifice economically to obtain a cleaner environment. To gauge such willingness, this research utilizes various economic measures that have been widely used, albeit with novel modifications. The focus of this research is on stated preferences about microplastic pollution. The topic of microplastics is still very novel, and market players on the demand side or on the supply side have yet to provide products that deal with this new pollutant. This lack has necessitated the need for stated preference research. This research delves into this novel environmental problem from various viewpoints.</p> <p> Chapter 1 of this research is about how much the US adult population is willing to sacrifice to obtain an environment that is less impacted by microplastic pollution. The results show that US adults in general possess a willingness to obtain an environment free from microplastics. However, a sizable minority of US adults do not show such willingness as well. Such results remained true even when information about microplastic pollution were provided to all respondents before preference elicitation. </p> <p> Chapter 2 investigates how much consumers in different countries will diverge about their willingness to pay for seafood that has less microplastic contamination. The countries chosen differed widely in their seafood consumption habits. Thus, it was hypothesized that such differences will lead to contrasts in their willingness to pay for less contaminated seafood. The hypothesis was found to be true but not in the way that was expected. The results show that frequent consumers of seafood had less willingness to pay when compared to others, although in whole all consumers showed willingness to avoid microplastics in their seafood. </p> <p> Chapter 3 makes use of the same data as Chapter 2 but looks at possible reasons for the disparity in responses besides factors explored in Chapter 2. Chapter 3 focuses on the cultural differences to explain the differences in behavior. To do so, it utilizes the Value-Belief-Norm theory widely employed in past research but modifies it to account for a form of hypothetical bias. The research delves into the relationships between many factors of interest that affect environmentally friendly consumption behavior and the findings show that a certain cultural tendency is central to such behavior, at least for microplastics. </p> <p> The research has done its best to research into the economic relationship between microplastic contamination of the environment and how much various individuals are willing to sacrifice to obtain an environment that is less impacted by such pollution. The findings here show that there is room for improvement in the way the microplastic pollution problem is being handled. However, in all settings the results show that a sizable majority want to be less impacted by microplastic pollution, a key takeaway for all interested parties.</p>

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24099号 / 工博第5021号 / 新制||工||1784(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 CRUZ Ana Maria , 教授 須崎 純一, 准教授 松島 格也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Bioenergy contributes significantly towards the share of renewable energies, in Europe and worldwide. Besides solid and liquid biofuels, gaseous biofuels, such as biogas or upgraded biogas (biomethane), are an established renewable fuel in Europe. Although many studies consider biomethane technologies, feedstock potentials, or sustainability issues, the literature on the required legislative framework for market introduction is limited. Therefore, this research aims at identifying the market and legislative framework conditions in the three leading biomethane markets in Europe and compare them to the framework conditions of the top six non-European biomethane markets. This study shows the global status and national differences in promoting this renewable energy carrier. For the cross-country comparison, a systematic and iterative literature review is conducted. The results show the top three European biomethane markets (Germany, United Kingdom, Sweden) and the six non-European biomethane markets (Brazil, Canada, China, Japan, South Korea, and the United States of America), pursuing different promotion approaches and framework conditions. Noteworthy cross-national findings are the role of state-level incentives, the tendency to utilise biomethane as vehicular fuel and the focus on residues and waste as feedstock for biomethane production. Presenting a cross-country comparison, this study supports cross-country learning for the promotion of renewable energies like biomethane and gives a pertinent overview of the work.

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Cross-country skiing has turned into the most highly competitive winter sport, with skiers having the ability to win by merely milliseconds. Every year researchers, ski - technicians, and athletes come together to prepare the ski base surface that gives the best possible results. However, much current information is based on the ski technician’s experience. Therefore, this project has been carried out to help to bridge the gap between ski technician’s knowledge and experimental research. The ski bases are passed through several surface preparation steps before competitions. Stone grinding and hand texturing are two of them. Since grinding cannot be specifically applied as per the environmental conditions, it is followed by texturing. This application of grinding and texturing changes the surface topography of the ski base, which will affect the contact area between the ski base surface and snow/ice and the wettability of the ski base. For this project, work is focused on how the application of different grinds and hand textures affects the wettability of the ski base. This project illustrates the change in wettability of ultra-high molecular weight polyethylene (UHMWPE) and its composites under the application of ten different commercial grinds followed by three other hands texturing. Surface topography was observed under an Optical profilometer, and wettability was measured by measuring the contact angles of droplets on these ski base materials. It was found that the hydrophobicity of ski base materials can be increased to a certain level by increasing the Arithmetic mean roughness (Ra) of specimens. Different ski base materials showed different hydrophobic behaviour when roughness was increased. Applying hand textured to different ground specimens again improved the hydrophobic behaviour of the ski base.

Poly- och perfluorerade ämnen, även kallad PFAS, har både globalt och i Sverige upptäckts i höga halter i mark samt i yt-och grundvatten de senaste åren. Kemikalierna är svårnedbrytbara och studier visar på att de bland annat är reproduktionsstörande hos djur. Källorna till utsläpp av PFAS är många, men något som uppmärksammats den senaste tiden är fluorvallor som används inom längdskidåkning. I den här studien undersöks hur användningen av skidvalla innehållande PFAS påverkar ett område samt hur dessa ämnen sprids. För att undersöka detta har tidigare mätningar utförda i anslutning till längdskidspår använts, för att se hur spridningen skett vid dem samt vilka koncentrationer som kan påträffas.  Mätningarna var utförda vid skidspår i Oslo, Trondheim, vid Vasaloppet samt vid en tävling i Maine, USA. För att visualisera var i Sverige påverkade områden skulle kunna finnas gjordes dessutom en karta där orter togs ut på två olika sätt. Skidvalla bidrar till att orsaka högre lokala koncentrationer av PFAS, och kan få en stor påverkan i de områden där mycket skidåkning pågår. Samtidigt är det svårt att dra tydliga slutsatser då det finns fåtal studier och många diffusa källor som kan bidra till spridningen av PFAS. / Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals used for their water, grease, and dirt repellent properties. Today these substances are widespread due to their ability to spread through both air and water. PFAS are long-term persistent and have hazardous environmental impact. Among others, affecting the reproduction of animals and has been shown to accumulate in the food chain. One product containing PFAS that has recently gained attention is fluorinated ski wax, due to the ban imposed on fluorinated ski wax by the International Ski Federation (FIS) from the season 2021/2022.  To investigate how the use of ski wax containing PFAS spreads and affects the environment at areas with cross-country skiing, results from previous studies have been analyzed. The previous studies were located at cross-country ski areas in Oslo and Trondheim in Norway, Maine in the USA and at the location of the Swedish competition Vasaloppet. A map has also been made to visualize where in Sweden there might be areas who have been contaminated with per- and polyfluoroalkyl substances by the use of ski wax. To find the locations for these areas two different methods have been used.  The results of the previous studies shows that the use of fluorinated ski waxes gives higher local concentrations of PFAS at the locations of cross-country ski areas that are frequently used. However, it is still difficult to draw clear conclusions about how big the spread of PFAS contamination is, since the substances can be found in many different products and are easily spread. In the future there is a need for more studies and investigation to reach clearer conclusions. In addition, there is a need for more tests around different ski areas to see the impact that competitions have, but also how everyday skiing affects the spread of PFAS.

Syfte Undersöka biomekaniska och fysiologiska skillnader mellan modern och gammeldags stakteknik vid konstant submaximalt arbete på rullskidor. Metod Tolv manliga elitskidåkare rekryterades till studien (ålder: 21 ± 4 år, längd: 183,6 ± 9,3 cm, och vikt: 77,8 ± 10,3 kg). Efter en standardiserad uppvärmning genomfördes två deltester, om fyra minuter vardera, i modern och gammeldags stakning med en individanpassad hastighet och lutningen 2,5°. Syreförbrukningen och ventilation analyserades under testen och efter varje deltest togs ett laktatprov och skattning av ansträngning utifrån Borgs RPE. Testerna filmades, där vinklar sedan plockades ut i ett videoanalysprogram. De olika testvärdena analyserade sedan med Paired samples t-test samt Paired samples Wilcoxon signed-ranked test. Resultat Ingen signifikant skillnad påvisades mellan modern och gammeldags stakning för syreförbrukning, energiförbrukning, rörelseekonomi, andningsfrekvens samt laktathalt. Signifikanta skillnader påvisades för hjärtfrekvens, ventilation, respiratory exchange ratio (RER) samt Borg RPE, där gammeldags stakning uppvisade högre värden för samtliga variabler förutom RER. Även i en del ledvinklar samt för tiden i den kraftskapande- och återhämtningsfasen stakcyklerna och tyngdpunktsförflyttningen. Slutsatser Studien visar inga signifikanta skillnader i energikostnad, syrekonsumtion, rörelseekonomi samt blodlaktatskoncentration mellan modern och gammeldags stakning vid submaximalt arbete. Däremot finns signifikanta skillnader i hjärtfrekvens, ventilation samt den skattade tröttheten som tyder på att gammeldags stakning upplevs något mer ansträngande. Framtida forskning behövsför att avgöra om detta skiljer sig i annan lutning och hastighet. / Purpose Examine whether biomechanical and physiological variables differ between modern and old-fashioned double poling technique (OFDP) at a constant submaximal work rate during roller skiing. Methods Twelve male elite cross-country skiers were recruited (age: 21 ± 4 years, length: 183,6 ± 9,3 cm, and weight: 77,8 ± 10,3 kg). After a standardized two subtests followed, in modern and OFDP technique at an individual velocity and the incline 2,5°. Oxygen consumption and ventilation were measured during the testand lactate concentration as well as estimation of Borg RPE were measuredafter every subtest. The test was recorded and angles were analysed. Test values were analysed using Paired samples t-test as well as Paired samples Wilcoxon signed-ranked test. Results No significant difference in energy expenditure (EE), O2 consumption, gross efficiency (GE), breathing frequency (BF) and lactate were shown. Significant differences were shown between heart rate (HR), ventilation, RER and Borg RPE, where higher values were shown for OFDP at all variables except RER. Significant differences were shown in some joint angles as well as the time of the power creating phase,returning phase of the pole stroke and the centre of mass (COM) displacement. Conclusions No significant difference in EE, O2 consumption, GE and lactate between modern and OFDP during a submaximal work rate. Differences in HR and estimated exhaustion gives a hint of the OFDP being more exhausting. Future research is required to determine if this differs in other inclines and velocities.

The aim of the thesis is to understand why European countries show a very different picture of female employment (in their fertile ages) which is not the case for men of the same age. We shed light on the various positions of countries in this framework of earner-carer models, in analysing policy designs, policy outcomes and policy determinants. That is, respectively, family policy indicators, employment of mothers and childless women, gender role attitudes and their interacting effect with policies and employment outcomes. We have used a wide range of primary or secondary quantitative and qualitative data to carry out our comparative analysis, mixing approaches, techniques and methods, from micro-econometric models to macro-level harmonised indicators, supplemented with a case study. The dissertation is divided in three parts, each focusing on one question: (i) Are there complementarities or distinctions between types of family policies across Europe, as regards gender equality and dual-earner friendliness, and how can we compare different policy settings as they are found to be very heterogeneous? (ii) To what extent can institutional settings explain cross-country differences in female employment outcomes, and especially those of mothers, in a context of decreasing fertility? (iii) Do individual preferences counteract (or reinforce) the policy impact on employment in connexion with the prevalence of traditional gender role attitudes? Results show that the institutional variation across countries explains a great deal of differences in female employment, especially for mothers. If policies are not supportive of the dual-earner model, even those women who have a stronger preference for labour market attachment face obstacles that reduce their employment opportunities in the presence of young children. However, even in countries where a somewhat dual-earner friendly model is favoured, our detailed analysis of policy instruments reveals that gender equality is still far from being achieved.

Elite athletes of today use specialized, scientific training methods and the increasing role of science in sports is undeniable. Scientific methods and equipment has even found its way into the practice of everyday exercisers, a testament to the impact of sport science. From the experiential, personal training regimes of the first half of the 20th century to the scientific training theories of the 1970s, the ideas about training and the athletic body shifted. The rationalization process started in endurance sports in the 1940s. It was part of a struggle between two models of training; natural training and rational training. Physiologists wanted to rid training of individual and local variations and create a universal model of rational, scientific training. The rationalization of training and training landscapes is here understood as an aspect of sportification, a theory commonly used to describe similar developments in sports where increasing regimentation, specialization and rationalization are among the main criteria. This dissertation adds the concept of technologies of sportification to explain the role that micro-technologies and practices (such as training logs, training camps and scientific tests) have in the scientization of training. This thesis thus sets out to analyze the role that science has played in training during the 20th century. It is a history about the rationalization of training, but also about larger issues regarding the role of personal, experiential knowledge and scientific knowledge. The main conclusions are that the process of scientization never managed to rid training of components from natural, experiential training, and that the effort by Swedish physiologists to introduce rational training was part of the larger rationalization movement at the time. In the end, training knowledge was a co-production between practitioners and theoreticians, skiers and scientists. / <p>QC 20161114</p> / Rationell träning: vetenskapliggörandet äv träning för längdskidåkning