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  • 105551.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Idrott, krig och svenska löparstjärnor: om idrottens samhällsetablering och den massmediala uppmärksamheten kring Gunder Hägg och friidrotten under andra världskriget2000In: Studier i idrott, historia och samhälle: tillägnade professor Jan Lindroth på hans 60-årsdag 23 februari 2000 / [ed] Johan R. Norberg, Stockholm: HLS Förlag, 2000, p. 293-325Chapter in book (Other academic)
  • 105552.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Idrotten tjänar på de politiska aktionerna och hot om bojkotter - om Davis Cup-matchen i Malmö och historien om politiska bojkotter runt idrotten.2009In: Newsmill.se, no 7 marsArticle in journal (Other (popular science, discussion, etc.))
  • 105553.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Idrottens framgångsspiral: om orsakssamband och framgångsfaktorer utifrån exemplen svensk tennis och svensk golf och deras prallella framgångsberättelser2010In: Idrottsforum.org, ISSN 1652-7224, Vol. 15 decemberArticle in journal (Other academic)
  • 105554.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Idrottshistoriska pionjärer går i pension. Recension av Sport as History: Essays in Honor of Wray Vamplew2011In: Idrottsforum.org, ISSN 1652-7224, no 14 decArticle, book review (Other academic)
  • 105555.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Kvinnor som utmanar män: Om elitidrottskvinnor som idrottsproffs, meideobjekt och celebriteter, samt upptåndelsen kring idrottsliga "könskamper" utifrån exemplen Billie Jean King och Annika Sörenstam2013In: Idrottsforum.org/Nordic sport science forum, ISSN 1652-7224, no 17 septemberArticle in journal (Other academic)
  • 105556.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Lucky Strike: svenska krigsbrudar, krigsbarn och allierade flygare. brottstycken från ett land i krig2014In: Militärhistorisk Tidskrift, ISSN 0283-8400Article, book review (Other academic)
  • 105557.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Nationell identitet i Kanada - före ishockeyn2010In: Idrottsforum.org, ISSN 1652-7224, Vol. 6 juniArticle, book review (Other academic)
  • 105558.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    När den stora massan kom på fötter - om uppsvinget för massidrott, kroppskultur och motionskampanjer i Sverige under andra världskriget.2003Article in journal (Other academic)
  • 105559.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Om fotboll som integration och makt - och Evitra Peron - i Argentina2015In: Idrottsforum.org/Nordic sport science forum, ISSN 1652-7224, no 8 septemberArticle, book review (Other academic)
  • 105560.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Om idrott, kropp, diskurser och nationell identitet - vilken verklighet är det vi studerar i massmedias konstruktioner av verkligheten?2009In: Idrottsforum.org, no 25 febrArticle in journal (Other academic)
  • 105561.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Om idrott, kropp, diskurser och nationell identitet - vilken verklighet är det vi studerar i massmedias konstruktioner av verkligheten?2009In: Idrott, historia & samhälle. Svenska idrottshistoriska föreningens årsskrift 2009., ISSN 0280-2775Article in journal (Other academic)
  • 105562.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Oviktiga detaljkunskaper - Om Levande historias syn på historielärare och historieämnets förutsättningar.2009In: Historielärarnas förenings årsskrift, ISSN 0439-2434w, p. 73-76Article in journal (Other (popular science, discussion, etc.))
  • 105563.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Svarta börsen - samhällslojalitet i kris: livsmedelsransoneringarna och den illegala handeln i Sverige 1940-19491992Doctoral thesis, monograph (Other academic)
  • 105564.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Svarta börsen i Sverige under andra världskriget1987In: Krig og moral: kriminalitet og kontroll i Norden under andre verdenskrig / [ed] Hannu Takala, Henrik Tham, Oslo: Universitetsforlaget, 1987, p. 261-280Chapter in book (Other academic)
  • 105565.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    The Swedish ´golf and tennis miracle´ - two parallell stories2011In: Nordic Elite Sport - same ambitions different tracks / [ed] Svein S. Andersen & Las Tore Ronglan, Oslo: Universitetsforlaget , 2011, 1, p. 109-130Chapter in book (Refereed)
  • 105566.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Veckan då Sörenstam utmanade männen och blev "Annika" med världen: Om idrottsstjärnor, celebriteter och känslor, eller en idrotsbagatell som blev en massmedial världshändelse2012In: Idrott, historia & samhälle, ISSN 0280-2775, no 1, p. 94-111Article in journal (Other academic)
  • 105567.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Vietnamkrigets mörka historia av brott mot civila, kvinnor och barn - ett brott mot mänskligheten,  recension av Döda allt som rör sig - det verkliga Vietnamkriget, av Nick Turse.2015In: Militärhistorisk Tidskrift, ISSN 0283-8400, no 1Article, book review (Other academic)
  • 105568.
    Wijk, Johnny
    Stockholm University, Faculty of Humanities, Department of History.
    Vietnemkrigets mörka historia av brott mot civila, kvinnor och barn – ett brott mot mänskligheten. Recension av Nick Turse, Döda allt som rör sig – det verkliga Vietnamkriget2015In: Militärhistorisk Tidskrift, ISSN 0283-8400, no 2, p. 205-211Article, book review (Other academic)
  • 105569.
    Wijk, Maria
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Inorganic Chemistry.
    Synthesis and characterisation of heterobimetallic erbium alkoxides1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes the synthesis and characterisation of alkoxides in the Er-M systems, where M = Al, Ti and Zr. The compounds found have been characterised by IR, UV-Vis DSC and single-crystal X-ray diffraction techniques and by chemical behaviour. It is shown that UV-Vis spectra can be used as an analytical tool to distinguish between different Er-containing alkoxides.

    Two homometallic erbium isopropoxides have been synthesised. The first (1) is assumed to be a solvated non-oxo-alkoxide, which decomposes almost quantitatively to Er5O(OPri)13 when it is evaporated or partially hydrolysed. Er5O(OPri)13 can also be synthesised directly in high yields, using a reaction that involves partial hydrolysis. The reactivity of Er5O(OPri)13 is demonstrated by the reaction with Al4(OPri)12. The Nd analogues are also presented.

    The structures of two different compounds in the Er-Al-isopropoxide system have been determined: Er2Al2(OPri)12(HOPri)2 and ErAl3(OPri)12, and a fourth[SGIW1] compound with the approximate Er-to-Al ratio 3:1 has also been found. ErAl3(OPri)12 could be syntesised using Er5O(OPri)13 as erbium source. This reaction was monitored by UV-Vis measurements and by IR studies of evaporated samples at different stages in the reaction. In the Er-Ti-ethoxide system only one compound could be isolated: Er2Ti4O2(OEt)18(HOEt)2, and partial hydrolysis was necessary in order to reach high yields. Synthesis under strictly anhydrous conditions produced only non-isolable compound(s). When using isopropanol in stead of ethanol, another oxo-alkoxide was formed: Er4TiO(OPri)13.

    In the Er-Zr-isopropoxide system, the compound Er2Zr2O(OPri)12(HOPri)3 is obtained both under anhydrous conditions and after partial hydrolysis. No alkoxides with higher Zr content are formed in this system.

    Most of the structural fragments, i.e. the M-O core structures (M = Er, Al, Ti and Zr) found in the different erbium-containing alkoxides, are rather common in both homometallic and heterometallic alkoxides. Examples of these fragments are: the square pyramidal M5O core, the C2h configuration (M4O62) and the "butterfly configuration" (M4O). Er2Al2(OPri)12(HOPri)2 is exceptional in containing the rarely seen linear arrangement of the M-O core.

  • 105570.
    Wijkander, Hans
    Stockholm University.
    Indirect corrections and disequilibrium pricing: studies in second-best policies1986Doctoral thesis, comprehensive summary (Other academic)
  • 105571.
    Wijkander, Keith
    Stockholm University.
    Kungshögar och sockenbildning: studier i Södermanlands administrativa indelning under vikingatid och tidig medeltid1983Doctoral thesis, monograph (Other academic)
  • 105572.
    Wijkman, Anders
    et al.
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre.
    Bankrupting nature: denying our planetary boundaries2012Book (Other (popular science, discussion, etc.))
  • 105573. Wijkman, Anders
    et al.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Vi kan inte förhandla med naturen2009Report (Other (popular science, discussion, etc.))
  • 105574.
    Wijkman, Per
    Stockholm University, Faculty of Social Sciences, Institute for International Economic Studies.
    Capital Movements and Economic Development: The Determinants of Capital Imports into Australia, Canada, and Sweden 1860-19141971Report (Other academic)
    Download full text (pdf)
    FULLTEXT01
  • 105575.
    Wijkman, Per
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Contributions to Evolutionary Computation1997Doctoral thesis, monograph (Other academic)
    Abstract [en]

    We present in this thesis (1) an alternative model in the field of evolutionary computation, and (2) an experimental platform that can be used to evaluate and compare many different models in evolutionary computation.

    The presented model is, like other models in evolutionary computation, based on the principle of natural selection. The difference between the presented model and the other models is a difference in the interpretation of the principle of natural selection. Traditional models in evolutionary computation provide only a partial interpretation of the principle of natural selection, while the presented model is based on a more complete interpretation. As a consequence, the presented model can deal with the problem of local optima in a novel way.

    We have built an experimental platform in such a way that a large number of different evolutionary models can be simulated and tested in parallel. We present the result of a number of such simulations. In the construction of this platform, we divided the platform into different modules so that new evolutionary mechanisms and new problem modules easily can be added.

  • 105576.
    Wijkmark, Nicklas
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kullander, Sven O.
    Barriga Salazar, Ramiro E.
    Andinoacara blombergi, a new species from the rio Esmeraldas basin in Ecuador and a review of A. rivulatus (Teleostei: Cichlidae)2012In: Ichthyological exploration of freshwaters, ISSN 0936-9902, Vol. 23, no 2, p. 117-137Article in journal (Refereed)
    Abstract [en]

    Andinoacara blombergi, new species, is described from the rio Esmeraldas basin in northern Ecuador. It is distinguished from the most similar species, A. rivulatus (Gunther, 1860) by 25 vs. 24 scales in the El scale row, slightly higher average meristics, narrower head, and narrower interorbital space. Andinoacara rivulatus is redescribed on the basis of specimens from the Guayas, Tumbes and Zarumilla drainages in Ecuador and Peru. Aequidens azurifer Fowler, 1911 is a junior synonym of A. rivulatus. The syntypes of Acara aequinoctialis Regan, 1905 are also syntypes of A. rivulatus. A common lectotype is designated for A. rivulatus and A. aequinoctialis, making A. aequinoctialis a junior objective synonym of A. rivulatus.

  • 105577.
    Wijkström, Filip
    et al.
    Handelshögskolan i Stockholm.
    Lundström, Tommy
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    Den ideella sektorn: organisationerna i det civila samhället2002Book (Other academic)
  • 105578. Wijkström, Filip
    et al.
    Reuter, MartaStockholm University, Faculty of Social Sciences, Department of Political Science.Emami, Abbas
    Civilsamhället i det transnationella rummet2017Collection (editor) (Other academic)
    Abstract [sv]

    Ibland ses det civila samhället som en alltigenom svensk historia. I denna nya bok uppmärksammas istället civilsamhällets plats i ett transnationellt rum av ständigt tilltagande aktiviteter och växande flöden av människor, resurser, information och idéer. De idéer som bär organisationslivets frågor och former har rest in från andra delar av världen. De översätts och vävs ihop med tidigare generationer samhälle, ibland vandrar de vidare. Så gick det till igår och så går det till idag. Med den transnationella blicken får vi syn på den pågående radikala omförhandlingen av systemet och på nationalstatens förändrade roll. I tolv aktuella kapitel möter läsaren forskare från olika discipliner och lärosäten med detaljerade analyser av civilsamhällets utveckling, men också motstånd och resistens.

    I bokens första kapitel sätts scenen för övriga kapitel. Vi möter Pride och undersöker kvinnorörelsens organisering i Europa. Vi får lära oss mer om både sparbankernas och konsumentkooperationens europeiska resor. Konturerna för ett nytt rum för importerad frivillighet och filantropi mejslas fram och arbetarrörelsens problem att hantera globaliseringen analyseras. Vi får veta vilka som är nationalstatens sista väktare, hur det går till när pappaskolor går på export, men också vad som kan hända med en transnationell gåva och varför en invandrarorganisation inte når hela vägen i sin europeiska strävan. Antologin är en fristående uppföljning på Civilsamhället i samhällskontraktet.

  • 105579. Wijnbladh, Erik
    et al.
    Jönsson, Bror Fredrik
    Kumblad, Linda
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Marine ecosystem modeling beyond the box: Using GIS to study carbon fluxes in a coastal ecosystem2006In: Ambio, Vol. 35, no 8, p. 484-495Article in journal (Refereed)
  • 105580.
    Wijnbladh, Gustav
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Olofsson, Fredrik
    Stockholm University, Faculty of Social Sciences, School of Business.
    Outsourcingmodell: En modell som anger de premisser, under vilka, det bör vara fördelaktigt att anlita en konsult vid outsourcing.2006Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Outsourcing är ett väletablerat begrepp som det har skrivits mycket om. När ett företag lägger ut delar av sin verksamhet till ett annat företag, så är det inte helt ovanligt att man utnyttjar en konsult för att hantera den praktiska processen. Den så kallade outsourcingprocessen. Konsulten (mellanhanden) marknadsför sig mot kunden (den outsourcande parten) som en motpol till de leverantörer (den part som verksamheten outsourcas till) som har stor erfarenhet av outsourcingprocessen och därmed ett övertag vid förhandlingar. Författarna vill i sin undersökning nå fram till en mer nyanserad bild av vilka fördelar respektive nackdelar det finns med att anlita en konsult av motsvarande slag. Den huvudsakliga frågeställningen i uppsatsen är följande: Under vilka förutsättningar borde ett företag kunna dra nytta av en mellanhand vid outsourcing. Syftet med detta är att ta fram en modell som anger under vilka förutsättningar som det kan anses motiverat att anlita en konsult för att hantera outsourcingprocessen. Uppgiften löses genom användandet av en kvalitativ metod; vilket i praktiken i detta fall innebär att resultatet från intervjuer och litteraturstudier tolkas. Uppsatsen inleds med en förstudie som baserar sig på intervju- och litteraturstudier. Resultaten från denna förstudie mynnar ut i ett utkast till en modell som är ämnad att korrespondera med vår frågeställning. Den empiri som bildar fyllningen i vår modell är upphängd över en ram som utgörs av en beslutsmodell. Efter att det första förslaget har tagits fram, testas den. I denna process låter vi en särskilt tillsatt grupp av experter granska modellen och avge kritik beträffande densamma. Vilket i sin tur ger den slutgiltiga modellen. Resultatet från undersökningen är en fantastiskt bra modell för den som är intresserad av att ta reda på under vilka förutsättningar ett företag kan dra nytta av en mellanhand i outsourcingprocessen.

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    FULLTEXT01
  • 105581.
    Wijnja, Jennie
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Hermansson, Lovisa
    Stockholm University, Faculty of Social Sciences, School of Business.
    Kaurén, Anna
    Stockholm University, Faculty of Social Sciences, School of Business.
    Organisationsteori enligt konstens alla regler: En filosofisk resa från upplysningsfilosofins estetikbegrepp till modernt företagande2003Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna uppsats har varit att studera huruvida estetiken kan vara ett användbart verktyg i en organisation för att skapa mervärde för den anställde, och därigenom för organisationen. Vi har koncentrerat oss på de effekter som ett estetiskt förhållningssätt kan ge, utan att föra resonemang kring effektivitet eller kostnader.

  • 105582.
    Wik, Annika
    Stockholm University, Faculty of Humanities, Department of Cinema Studies.
    Experiences: The Transmedial Expansion of the Matrix Universe2010In: Acta Universitatis Sapientiae. Film and Media Studies, ISSN 2065-5924, Vol. 2, p. 73-90Article in journal (Refereed)
  • 105583.
    Wik, Annika
    Stockholm University, Faculty of Humanities, Department of Cinema Studies.
    Förebild film: panoreringar över den samtida konstscenen2001Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The contemporary art scene includes a large number of art works which utilise existing film material. This dissertation assesses many of these works and includes artists such as Douglas Gordon, Christoph Girardet, Stephanie Smith, Pierre Bismuth, Pierre Huyghe, Susan Hiller, Matthias Müller, Fiona Banner, Stan Douglas, Christoph Draeger, and others who have worked in a similar field. Today, these frequent but specific art events are part of an art tradition as well as a film tradition, and their explicit interartiality calls for an interdisciplinary research method. This dissertation, therefore, closely examines the interrelation of art and film, and the intersection between art and film theory, drawing upon the broad field generally referred to as "visual theory" or "visual culture".

    The purpose of this dissertation is to study the phenomenon of audio-visual appropriation. By discussing the relation between the "ready-made", and the strategy of "appropriation" and "rearticulation", a theoretical background to the concept of audio-visual appropriation is formed in Chapter 1 and Chapter 2. The following three chapters are devoted to analyses of art events that have taken place from the late 1970s, with emphasis on the 1990s, and concern the conceptual, aesthetic, and contextual tendencies in the contemporary art scene. The art scene is here understood as a discursive field of the art event, gallery space, exhibitions, texts, reviews, and academic discourse. The most frequently encountered film material are the films of Alfred Hitchcock, but a great many other films are also used. New meanings are generated by the new works as well as for the films that have been used. Just as familiar films are experienced in new ways as they are transferred to an art institutional context, this study throws new light on the contemporary art scene and the changes which have taken place when film plays such a major role. 

  • 105584.
    Wik, Annika
    Stockholm University, Faculty of Humanities, Department of Cinema Studies. Stockholm University, Faculty of Humanities, Department of Cinema Studies.
    Upplevelse2008In: Film och andra rörliga bilder - en introduktion, 2008, p. 203-220Chapter in book (Other academic)
  • 105585.
    Wik, Annika
    et al.
    Stockholm University, Faculty of Humanities, Department of Cinema Studies.
    Malm, Magdalena
    Rörlig konstproduktion: Mobile Art Production (sv/eng, tvåspråkig)2010Book (Other academic)
  • 105586.
    Wik, Kristofer
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Davidsson, Tomas
    Stockholm University, Faculty of Social Sciences, School of Business.
    Kompetens och kompetensförsörjning - en fallstudie av Crevita1999Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats är baserad på en studie av IT-bolaget Crevita i Uppsala. Avsikten med problemformuleringen är att granska hur företaget definierar kompetens samt hur kompetensförsörjning sker i praktiken. Syftet med uppsatsen är att belysa varför verkligheten, i denna studie Crevitas kompetensdefinition och kompetensförsörjning, är,sålunda utformad.

  • 105587.
    Wik, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Emission of methane from northern lakes and ponds2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Northern lakes and ponds are abundant and emit large amounts of the potent climate forcer methane to the atmosphere at rates prone to change with amplified Arctic warming. In spite of being important, fluxes from surface waters are not well understood. Long-term measurements are lacking and the dominant and irregular transport mode ebullition (bubbling) is rarely quantified, which complicate the inclusion of lakes and ponds in the global methane budget. This thesis focuses on variations in emissions on both local and regional scales. A synthesis of methane fluxes from almost all studied sites constrains uncertainties and demonstrates that northern lakes and ponds are a dominant source at high latitudes. Per unit area variations in flux magnitudes among different types of water bodies are mainly linked to water depth and type of sediment. When extrapolated, total area is key and thus post-glacial lakes dominate emissions over water bodies formed by peat degradation or thermokarst processes. Further, consistent multiyear measurements in three post-glacial lakes in Stordalen, northern Sweden, reveal that seasonal ebullition, primarily driven by fermentation of acetate, can be predicted by easily measured parameters such as temperature and heat energy input over the ice-free season. Assuming that most water bodies respond similarly to warming, this thesis also suggests that northern lakes and ponds will release substantially more methane before the end of the century, primarily as a result of longer ice-free seasons. Improved uncertainty reductions of both current and future estimates rely on increased knowledge of landscape-level processes related to changes in aquatic systems and organic loading with permafrost thaw, as well as more high-quality measurements, seldom seen in contemporary data. Sampling distributed over entire ice-free seasons and across different depth zones is crucial for accurately quantifying methane emissions from northern lakes and ponds.

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  • 105588.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Bastviken, David
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Danielsson, Åsa
    Norback, Elin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Bubbles trapped in arctic lake ice: Potential implications for methane emissions2011In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 116, p. G03044-Article in journal (Refereed)
    Abstract [en]

    The amount of methane (CH(4)) emitted from northern lakes to the atmosphere is uncertain but is expected to increase as a result of arctic warming. A majority of CH4 is thought to be released through ebullition (bubbling), a pathway with extreme spatial variability that limits the accuracy of measurements. We assessed ebullition during early and late winter by quantifying bubbles trapped in the ice cover of two lakes in a landscape with degrading permafrost in arctic Sweden using random transect sampling and a digital image processing technique. Bubbles covered up to similar to 8% of the lake area and were largely dominated by point source emissions with spatial variabilities of up to 1056%. Bubble occurrence differed significantly between early and late season ice, between the two lakes and among different zones within each lake (p < 0.001). Using a common method, we calculated winter fluxes of up to 129 +/- 486 mg CH(4) m(-2) d(-1). These calculations are, on average, two times higher than estimates from North Siberian and Alaskan lakes and four times higher than emissions measured from the same lakes during summer. Therefore, the calculations are likely overestimates and point to the likelihood that estimating CH(4) fluxes from ice bubble distributions may be more difficult than believed. This study also shows that bubbles quantified using few transects will most likely be unsuitable in making large-scale flux estimates. At least 19 transects covering similar to 1% of the lake area were required to examine ebullition with high precision in our studied lakes.

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  • 105589.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Varner, Ruth K.
    Bastviken, David
    Stockholm University, Faculty of Science, Department of Geological Sciences. Linköping University, Sweden.
    Multiyear measurements of ebullitive methane flux from three subarctic lakes2013In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 118, no 3, p. 1307-1321Article in journal (Refereed)
    Abstract [en]

    Ebullition (bubbling) from small lakes and ponds at high latitudes is an important yet unconstrained source of atmospheric methane (CH4). Small water bodies are most abundant in permanently frozen peatlands, and it is speculated that their emissions will increase as the permafrost thaws. We made 6806 measurements of CH4 ebullition during four consecutive summers using a total of 40 bubble traps that were systematically distributed across the depth zones of three lakes in a sporadic permafrost landscape in northernmost Sweden. We identified significant spatial and temporal variations in ebullition and observed a large spread in the bubbles' CH4 concentration, ranging from 0.04% to 98.6%. Ebullition followed lake temperatures, and releases were significantly larger during periods with decreasing atmospheric pressure. Although shallow zone ebullition dominated the seasonal bubble CH4 flux, we found a shift in the depth dependency towards higher fluxes from intermediate and deep zones in early fall. The average daily flux of 13.4mg CH4 m(-2) was lower than those measured in most other high-latitude lakes. Locally, however, our study lakes are a substantial CH4 source; we estimate that 350kg of CH4 is released via ebullition during summer (June-September), which is approximately 40% of total whole year emissions from the nearby peatland. In order to capture the large variability and to accurately scale lake CH4 ebullition temporally and spatially, frequent measurements over long time periods are critical.

  • 105590.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Johnson, Joel E.
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    DeStasio, Joel P.
    Erickson, Lance
    Halloran, Madison J.
    Fahnestock, M. Florencia
    Crawford, Maurice K.
    Phillips, Stephen C.
    Varner, Ruth K.
    Sediment Characteristics and Methane Ebullition in Three Subarctic Lakes2018In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 123, no 8, p. 2399-2411Article in journal (Refereed)
    Abstract [en]

    Ebullition (bubbling) from climate-sensitive northern lakes remains an unconstrained source of atmospheric methane (CH4). Although the focus of many recent studies, ebullition is rarely linked to the physical characteristics of lakes. In this study we analyze the sediments of subarctic postglacial lakes and investigate how sediment properties relate to the large spatial variation in CH4 bubble flux, quantified over multiple years using bubble traps. The results show that the sediments from our lakes are rich in total organic carbon, containing 37 kg/m(3) on average. This number is roughly 40% higher than the average for yedoma deposits, which have been identified as high CH4 emitters. However, the quantity of total organic carbon is not a useful indicator of high emissions from the study lakes. Neither is the amount of CH4 in the sediment a reliable measure of ebullition potential. Instead, our data point to coarse detritus, partly from buried submerged aquatic vegetation and redeposited peat as spatial controls on fluxes, often in combination with previously established effects of incoming solar radiation and water depth. The results once again highlight the climate sensitivity of northern lakes, indicating that biological responses to warmer waters and increased energy input and heating of organic sediments during longer ice-free seasons can substantially alter future CH4 emissions.

  • 105591.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Thornton, Brett F.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Bastviken, David
    MacIntyre, Sally
    Varner, Ruth K.
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Energy input is primary controller of methane bubbling in subarctic lakes2014In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 41, no 2, p. 555-560Article in journal (Refereed)
    Abstract [en]

    Emission of methane (CH4) from surface waters is often dominated by ebullition (bubbling), a transport mode with high-spatiotemporal variability. Based on new and extensive CH4 ebullition data, we demonstrate striking correlations (r(2) between 0.92 and 0.997) when comparing seasonal bubble CH4 flux from three shallow subarctic lakes to four readily measurable proxies of incoming energy flux and daily flux magnitudes to surface sediment temperature (r(2) between 0.86 and 0.94). Our results after continuous multiyear sampling suggest that CH4 ebullition is a predictable process, and that heat flux into the lakes is the dominant driver of gas production and release. Future changes in the energy received by lakes and ponds due to shorter ice-covered seasons will predictably alter the ebullitive CH4 flux from freshwater systems across northern landscapes. This finding is critical for our understanding of the dynamics of radiatively important trace gas sources and associated climate feedback.

  • 105592.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Thornton, Brett F.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Bastviken, David
    Uhlbäck, Jo
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Biased sampling of methane release from northern lakes: A problem for extrapolation2016In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 3, p. 1256-1262Article in journal (Refereed)
    Abstract [en]

    Methane emissions from lakes are widely thought to be highly irregular and difficult to quantify with anything other than numerous distributed measurement stations and long-term sampling campaigns. In spite of this, a large majority of the study sites north of 50°N have been measured over surprisingly short time periods of only one to a few days. Using long-term data from three intensively studied small subarctic lakes, we recommend that measurements of diffusive methane flux and ebullition should be made over at least 11 and 39 days scattered throughout the ice-free season using depth-stratified sampling at 3 and 11 or more locations, respectively. We further show that low temporal and spatial resolutions are unlikely to cause overestimates. Therefore, we argue that most sites measured previously are likely underestimated in terms of emission potential. Avoiding these biases seen in much of the contemporary data is crucial to further constrain large-scale methane emissions from northern lakes and ponds.

  • 105593.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Varner, Ruth K.
    Thornton, Brett
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    McCalley, Carmody
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Large isotopic variations and similarities in methane ebullition from northern lakesManuscript (preprint) (Other academic)
    Abstract [en]

    Lakes are abundant in northern, high latitude landscapes and considered a substantial source of atmospheric methane (CH4). In spite of this, little is known about how CH4 release mechanisms relate to underlying organic sources and biogenic production pathways in different types of water bodies. Here, we present a substantial, multiyear dataset of the stable isotopes of CH4 ebullition from three interconnected, subarctic post-glacial lakes. The δ13C-CH4 and δD-CH4 vary from -78.4 to -53.1‰ and from -369.8 to -218.8‰, respectively. Overall, these observations suggest predominantly acetoclastic methanogenesis in the shallow zones, possibly fueled by in-situ plant production, and a shift towards a mix with hydrogenotrophy at depth. The bubbles’ δ13C-CH4 are similar to most of those reported from other northern natural systems, but we found differences in δD-CH4, possibly due to evaporation-driven fractionation over summer. Stable isotopes provide valuable information about underlying organic sources and production pathways, however, due to large overlaps they may not be effective in reducing uncertainties in emissions potentials among different water body types, and in general between lakes and wetlands.

  • 105594.
    Wik, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Varner, Ruth K.
    Walter Anthony, Katey
    MacIntyre, Sally
    Bastviken, David
    Climate-sensitive northern lakes and ponds are critical components of methane release2016In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 9, p. 99-105Article, review/survey (Refereed)
    Abstract [en]

    Lakes and ponds represent one of the largest natural sources of the greenhouse gas methane. By surface area, almost half of these waters are located in the boreal region and northwards. A synthesis of measurements of methane emissions from 733 lakes and ponds north of ~50° N, combined with new inventories of inland waters, reveals that emissions from these high latitudes amount to around 16.5 Tg CH4 yr−1 (12.4 Tg CH4-C yr−1). This estimate — from lakes and ponds alone — is equivalent to roughly two-thirds of the inverse model calculation of all natural methane sources in the region. Thermokarst water bodies have received attention for their high emission rates, but we find that post-glacial lakes are a larger regional source due to their larger areal extent. Water body depth, sediment type and ecoclimatic region are also important in explaining variation in methane fluxes. Depending on whether warming and permafrost thaw cause expansion or contraction of lake and pond areal coverage, we estimate that annual water body emissions will increase by 20–54% before the end of the century if ice-free seasons are extended by 20 days. We conclude that lakes and ponds are a dominant methane source at high northern latitudes.

  • 105595.
    Wik, Michaela
    Stockholm University, Faculty of Law, Department of Law.
    Children´s consent to medical treatment: with emphasis on essential treatments and the procedural protection of children´s rights2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
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    Michaela_Wik
  • 105596.
    Wik, Theres
    Stockholm University, Faculty of Humanities, Department of Asian, Middle Eastern and Turkish Studies, Japanese Studies.
    Dancing Gods at Godless Festivals: An Introduction to the Phenomenon of Japanese Dance Yosakoi through a Comparative Analysis of Three Yosakoi Performances with the Theme Princess Kaguya2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
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    fulltext
  • 105597.
    Wikander, Håkan
    Stockholm University, Faculty of Humanities, Department of Literature and History of Ideas.
    Plats för läsaren?: En receptionsteoretisk studie av tre barnböcker2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta arbete har varit att med utgångspunkter i forskning om läsförståelse samt receptionsteorier studera tre aktuella barnböcker för att se om och hur de ger läsaren möjlighet till textrörlighet genom att erbjuda plats att fylla i tomrum och oklarheter, och om de därigenom ger läsaren stöd i sin utveckling av läsförståelse. Man kan se studien som ett sätt att skapa sig en uppfattning om en bok utifrån en aspekt på att utveckla och stödja läsförståelse. Böckerna har analyserats med avseende på textens beskrivningar av personer, miljö och händelser, samt textens temporalitet och sätt att berätta. Resultatet visar att två av böckerna kan betraktas som stödjande i läsares utveckling av läsförståelse, medan den tredje uppvisar oklarheter som är svårlösta och kan därför ifrågasättas i det hänseendet.

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    fulltext
  • 105598.
    Wikander, Ulla
    Stockholm University, Faculty of Social Sciences, Department of Economic History.
    Delat arbete, delad makt: om kvinnors underordning i och genom arbetet. En historisk essä1992In: Kontrakt i kris: Om kvinnors plats i välfärdsstaten / [ed] Gertrud Åström och Yvonne Hirdman, Stockholm: Carlsson , 1992, p. 21-84Chapter in book (Other academic)
  • 105599.
    Wikander, Ulla
    Stockholm University, Faculty of Social Sciences, Department of Economic History.
    Demands on the ILO by Internationally Organized Women in 19192010In: ILO Histories : Essays on the International Labour Organization and Its Impact on the World During the Twentieth Century / [ed] Jasmien Van Daele, Magaly Rodríguez Garćia, Geert Van Goethem, Marcel van der Linden, Bern: ILO , 2010, p. 67-89Chapter in book (Other academic)
  • 105600.
    Wikander, Ulla
    Stockholm University, Faculty of Social Sciences, Department of Economic History.
    Det evigt kvinnliga: en historia om förändring1994Collection (editor) (Other academic)
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