The impact of permafrost degradation on methane fluxes : a field study in Abisko

All over the arctic and sub-arctic region global warming is affecting permafrost. When permafrost thaws, organic material becomes available for decomposition, hence an increase of greenhouse gas emissions to the atmosphere. In the northernmost of Sweden, on a mire close to Abisko, a snow manipulation project is ongoing. The experiment is trying to mimic predictions of future conditions and advance the thawing of permafrost. This is done by setting up snow fences which concentrated the snow to a certain area. In this thesis the measurements of methane were conducted inside of the existing snow manipulation project with the closed chamber technique, both in control and manipulated plots. Other variables that could affect the emissions were also collected or measured. The results show much higher methane emissions from manipulated plots. Average emissions from manipulated plots were 0.66 mg CH4 m-2 h-1 compared to 0.16 mg CH4 m-2 h-1 from control plots. Variables that showed the highest correlation with the methane flux was water table and active layer. Higher water table and thicker active layer for manipulated plots (higher emissions of CH4) and the opposite for control plots (lower emissions of CH4). If the trend of the global warming is continuing it will lead to even more thawing of permafrost. Then even more organic material will be available for decomposition and even more methane will be produced, adding to the global warming.All over the arctic and sub-arctic region global warming is affecting permafrost. When permafrost thaws, organic material that has been frozen shut in the soil becomes available for decomposition. During the process of decomposition greenhouse gases such as methane is produced, hence adding to global warming. In the northernmost of Sweden, on a mire close to Abisko, there is an ongoing experiment with permafrost. The experiment is trying to mimic predictions of future conditions and advance the thawing of permafrost. This was done by setting up a snow fence which concentrated the snow to a certain area. This in turn leads to changes in greenhouse gas fluxes. In this thesis measurements of methane were conducted both from plots where there had been manipulations done to advance the thawing of the permafrost and from control plots. Other variables that could affect the emissions were also collected or measured. The results show much higher methane emissions from areas where manipulations have been made. Average emissions from manipulated plots were 0.66 mg CH4 m-2 h-1 compared to 0.16 mg CH4 m-2 h-1 from control plots. The results are not only affected by the direct effects of the manipulations (a thicker snow cover). Other indirect variables such as the amount of thawed permafrost, the active layer, and the level of the water table also had an impact. Where the highest emissions were occurring, the thickest active layer and the highest water table was also present. If the trend of the global warming is continuing it will lead to even more thawing of permafrost. Then even more organic material will be available for decomposition and even more methane will be produced, adding to the global warming

The relationship between oil prices and the BRICS stock markets before and after the onset of Covid-19 pandemic : Differences in oil importing and oil exporting countries

The purpose of this study is to examine the relationship between the BRICS stock markets and global oil prices. The paper investigates how the fluctuations in oil prices impact the stock returns in BRICS countries before and after the onset of Covid-19 pandemic. The BRICS countries have become an important part of the global financial markets, and they are among the fastest growing economies in the world. Hence it is essential for market participants to understand the influence of different global factors, such as oil price, on these markets. In addition to their importance for the global financial markets, the BRICS countries include some of the most important oil exporters and oil importers in the world. Therefore it will be interesting to examine whether there are differences in the oil price-stock market relationship between the oil importing and oil exporting BRICS economies. The study uses the daily MSCI index returns of each BRICS stock market as well as the Brent and WTI oil prices. The daily returns are analyzed over a period from November 19, 2014 to January 30, 2023. This study utilizes a multiple linear regression model in order to empirically examine whether there is a significant relationship between the global oil prices and the BRICS stock returns during the study period. In order to control the macroeconomic circumstances, exchange rate and interest rate changes are added to the model as control variables, in addition to the global market returns. The empirical analysis finds evidence that, in general, there is a significant relationship between the BRICS stock returns and global oil prices. The degree of the relationship is not consistent through the whole study period, and it varies between oil importing and oil exporting countries. Oil exporting countries have a positive and generally stronger relationship with the oil price movements, whereas in oil importing countries, the relationship is mostly negative. Additionally, in contrast to previous studies, not much evidence is found of a stronger relationship since the onset of the Covid-19 pandemic.Tämän tutkimuksen tarkoituksena on tutkia BRICS osakkemarkkinoiden ja globaalien öljyn hintojen välistä yhteyttä. Tutkimus selvittää, kuinka heilunnat öljyn hinnassa vaikuttavat osaketuottoihin BRICS maissa ennen koronapandemian alkua sekä sen jälkeen. BRICS maista on tullut tärkeä osa globaaleja rahoitusmarkkinoita ja ne ovat maailman nopeiten kasvavien talouksien joukossa. Sen vuoksi markkinaosapuolille on tärkeää ymmärtää globaalien muuttujien, kuten öljyn hinnan, vaikutus näillä markkinoilla. Sen lisäksi, että BRICS mailla on merkittävä vaikutus globaaleihin rahoitusmarkkinoihin, nämä maat ovat yksiä maailman tärkeimpiä öljyn viejiä ja tuojia. Niinpä on mielenkiintoista tutkia onko öljyn hinnan ja osakemarkkinoiden välisessä suhteessa eroja niiden BRICS maiden välillä, jotka ovat öljyn tuojia ja niiden, jotka ovat öljyn viejiä. Tutkimus käyttää päivittäisiä MSCI indeksituottoja jokaiselta BRICS osakemarkkinalta ja lisäksi Brent ja WTI -öljyjen hintoja. Päivittäisiä tuottoja analysoidaan ajanjaksolla, joka alkaa 19. marraskuuta, 2014 ja päättyy 30. tammikuuta, 2023. Tämä työ hyödyntää usean muut-tujan lineaarista regressioanalyysia tutkiakseen empiirisesti, onko globaalien öljyn hintojen ja BRICS osaketuottojen välillä merkittävää suhdetta tutkimusajanjakson aikana. Jotta makroekonomisia olosuhteita voidaan kontrolloida, valuuttakurssi- ja korkokurssimuutokset lisätään regressioon kontrollimuutujiksi, globaalien markkinatuottojen lisäksi. Empiirisen analyysin tulokset osoittavat, että yleisesti BRICS osaketuottojen ja globaalien öljyn hintojen välillä on merkittävä suhde. Suhteen aste ei ole yhtenäinen koko tutkimusjakson ajan ja se vaihtelee öljyn tuonti- ja öljyn vientimaiden välillä. Öljyn viejämailla on positiivinen ja yleisesti vahvempi suhde öljyn hintojen kanssa, kun taas öljyn tuojamailla suhden on enimmäkseen negatiivinen. Lisäksi, verrattuna aiempiin tutkimuksiin, vahvemmasta suhteesta koronapandemian alkamisen jälkeen ei juurikaan löydetty todisteita

The New Informatics

The discipline that used to be called “information systems” is changing its identity. In Sweden, we have emphasized this reorientation by changing our name from “administrative data processing” to “informatics.” I will attempt to characterize this new informatics, describing it as a theory and design oriented study of information technology use, an artificial science with the intertwined complex of people and information technology as its subject matter. I will end by giving some suggestions for how to think of a new curriculum

A high-performance data structure for mobile information systems

Mobile information systems can now be provided on small form-factor computers. Dictionary-based data compression extends the capabilities of systems with limited processing and memory to enable data intensive applications to be supported in such environments. The nature of judicial sentencing decisions requires that a support system provides accurate and up-to-date data and is compatible with the professional working experience of a judge. The difficulties caused by mobility and the data dependence of the decision-making process are addressed by an Internet-based architecture for collecting and distributing system data.We describe an approach to dictionary-based data compression and the structure of an information system that makes use of this technology

Mobile Informatics

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AN ARTIFICIAL WORLD: An invitation to creative conversations on future use and design of computer technology

Aims and methods for the practice of system development were formulated in relation to early computer technology use in the sixties. These aims and methods provided a foundation for research and a framework for discussion which still set the agenda for theoretical work. Changes in computer technology use in the eighties raise issues that tend to fall outside the established research tradition. New user groups, the industrialization of software development, a tremendous diversification of computer technology use, and profound changes in society, everyday life, and world view broaden the need for research on how to put computer technology to good human use. In this paper we want to contribute to a discussion of how this challenge can be met, in general, and by the system development community, in particular

Ansvarsgenombrott - en jämförelse av gällande rätt och ny hovrättspraxis

Ett mycket omdiskuterat fenomen i svensk doktrin är när aktieägare åläggs ett ansvar för aktiebolagets förpliktelser trots ansvarsbegränsningen i 1 kap. 3§ ABL. Detta fenomen har kommit att kallas för ansvarsgenombrott. I två nyligen avkunnade hovrättsdomar har ansvarsgenombrott använts för att motivera ett sådant genombrott av 1 kap. 3§ ABL. Båda rättsfallen behandlade bolag vars enda syfte var att driva rättsprocesser, s.k. processbo-lag. Följande undersökning avser att utreda ifall HovR hade stöd för sina domskäl i gällande rätt. För att genomföra en sådan undersökning är en utgångspunkt att gällande rätt först utreds. Vad gällande rätt på området består i visade sig efter en undersökning av prejudikat, doktrin och lagförarbeten vara mycket svårt att konstatera. Samt-liga prejudikat präglades av oklarhet och inga principiella ställningstaganden togs av HD i något av rättsfallen. Doktrin har därav också kommit att präglas av osäkerhet och till viss mån oenighet om vad som egentligen krävs för att ansvarsgenombrott ska ske i svensk rätt. Det enda försök som gjorts för att instifta en generell lagregel på området avvisades och lagförarbeten därefter har inte erkänt ett behov av en sådan regel. De allra flesta tycks dock vara överens om ansvarsgenombrottets existens. Något konstaterande om institutets närmare innebörd och omfång är däremot inte möjligt att göra i dagsläget. Domskälen i de båda hovrättsdomarna blir därför av naturliga skäl i högsta grad präglade av denna osäkerhet. Stödet för utgången i de båda målen bygger på ett uttalande i doktrin från Rhode år 1984. Detta är ett stöd som inte bara är mindre lämpligt i sammanhanget då det dels bortser från all senare doktrin och samtliga lagförarbeten på området och dels för att Rhode baserat sitt resonemang på ett vagt rättsfall i ett internationellt perspektiv. Undersökningen går också vidare och konstaterar att ett behov av en generell lagregel på området numera existerar för att råda bukt med processbolag och potentiellt framtida bolagskonstruktioner av liknande slag

Optimal use of radar radial winds in the HARMONIE numerical weather prediction system

The use of radial velocity information from the European weather radar network is a challenging task, due to a rather heterogeneous radar network and the different ways of providing the Doppler velocity information. A preprocessing is therefore needed to harmonize the data. Radar observations consist of a very high resolution dataset which means that it is both demanding to process as well as that the inherent resolution is much higher than the model resolution. One way of reducing the amount of data is to create super observations (SO) by averaging observations in a predefined area. This paper describes the preprocessing necessary to use radar radial velocities in the data assimilation where the SO construction is included. The main focus is to optimize the use of radial velocities in the HARMONIE-AROME numerical weather model. Several experiments were run to find the best settings for first-guess check limits as well as a tuning of the observation error value. The optimal size of the SO and the corresponding thinning distance for radar radial velocities was also studied. It was found that the radial velocity information and the reflectivity from weather radars can be treated differently when it comes to the size of the SO and the thinning. A positive impact was found when adding the velocities together with the reflectivity using the same SO size and thinning distance, but the best results were found when the SO and thinning distance for the radial velocities are smaller compared to the corresponding values for reflectivity

A theoretical evaluation of the impact of the type of reaction on heat production and material losses in biomass piles

Self-heating during storage of biomass in piles causes material losses, leads to emissions to air, and poses a risk of fire. There are different techniques to assess a biomass material's propensity for self-heating, some of these are briefly reviewed. One of these techniques is isothermal calorimetry, which measures thermal power from materials and produces time-resolved curves. A recently developed and published test standard, ISO 20049-1:2020, describes how the self-heating of pelletized biofuels can be determined by means of isothermal calorimetry and how thermal power and the total heat produced during the test should be measured by isothermal calorimetry. This paper supports interpretation of the result obtained by isothermal calorimetry; the mentioned standard provides examples of peak thermal power and total heat but does not provide any assistance on how the result from isothermal measurements should be interpreted or how the result from measurements on different samples could be compared. This paper addresses the impact of different types of reactions, peak thermal power, total heat released (heat of reaction), activation energy, heat conductivity, and pile size on the temperature development in a generic pile of biomass. This paper addresses important parameters when the result from isothermal calorimetry is evaluated. The most important parameter, with respect to temperature development in large piles, was found to be the total heat released. It was also proposed that safe storage times, that is, the time until a run-away of the temperature in the pile, could be ranked based on the time to the peak thermal power