Change search
Refine search result
2088208920902091209220932094 104501 - 104550 of 105609
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 104501.
    Éll, Alida H
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Csjernyik, Gábor
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Slagt, Vincent F
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Berner, Simon
    Puglia, Carla
    Greger, Ledung
    Oscarsson, Sven
    Synthesis os S-Thioacetate Functionalized Cobalt(II) Porphyrins and Heterogenization on gold Surface2006In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 5, p. 1193-1199Article in journal (Refereed)
    Abstract [en]

    Cobalt tetraarylporphyrins 1-Co and 2-Co with thioacetate-functionalized carbon chains on the aryl groups were synthesized. The cobalt porphyrin 2-Co was immobilized on a gold surface after deprotection of the S-acetyl group. The immobilized porphyrin was studied by X-ray Photoelectron Spectroscopy (XPS) and the results suggest that a complete monolayer of porphyrins is formed.

  • 104502. Éll, Alida H
    et al.
    Samec, Joseph S M
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Brasse, Claudia
    Bäckvall, Jan-E
    Dehydrogenation of aromatic amines to imines via ruthenium-catalyzed hydrogen transfer2002In: Chemical Communications, ISSN 1359-7345, no 10, p. 1144 - 1145Article in journal (Refereed)
  • 104503.
    Ólafsdóttir, Hildigunnur
    et al.
    Reykjavík akademi.
    Leifman, Håkan
    Stockholm University, Faculty of Social Sciences, Centre for Social Research on Alcohol and Drugs (SoRAD).
    Legalizing beer in Iceland: its effects on alcohol consumption in times of recession2002In: The effects of Nordic alcohol policies: what happens to drinking and harm when alcohol controls change? / [ed] Robin Room, Helsingfors: Nordiska nämnden för alkohol- och drogforskning (NAD) , 2002, p. 95-116Chapter in book (Other academic)
  • 104504.
    Ólafsson, Einar B.
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Varas-Godoy, Manuel
    Barragan, Antonio
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Toxoplasma gondii infection shifts dendritic cells into an amoeboid rapid migration mode encompassing podosome dissolution, secretion of TIMP-1, and reduced proteolysis of extracellular matrix2018In: Cellular Microbiology, ISSN 1462-5814, E-ISSN 1462-5822, Vol. 20, no 3, article id e12808Article in journal (Refereed)
    Abstract [en]

    Dendritic cells (DCs) infected by Toxoplasma gondii rapidly acquire a hypermigratory phenotype that promotes systemic parasite dissemination by a Trojan horse mechanism in mice. Recent paradigms of leukocyte migration have identified the amoeboid migration mode of DCs as particularly suited for rapid locomotion in extracellular matrix and tissues. Here, we have developed a microscopy-based high-throughput approach to assess motility and matrix degradation by Toxoplasma-challenged murine and human DCs. DCs challenged with T.gondii exhibited dependency on metalloproteinase activity for hypermotility and transmigration but, strikingly, also dramatically reduced pericellular proteolysis. Toxoplasma-challenged DCs up-regulated expression and secretion of tissue inhibitor of metalloproteinases-1 (TIMP-1) and their supernatants impaired matrix degradation by naive DCs and by-stander DCs dose dependently. Gene silencing of TIMP-1 by short hairpin RNA restored matrix degradation activity in Toxoplasma-infected DCs. Additionally, dissolution of podosome structures in parasitised DCs coincided with abrogated matrix degradation. Toxoplasma lysates inhibited pericellular proteolysis in a MyD88-dependent fashion whereas abrogated proteolysis persevered in Toxoplasma-infected MyD88-deficient DCs. This indicated that both TLR/MyD88-dependent and TLR/MyD88-independent signalling pathways mediated podosome dissolution and the abrogated matrix degradation. We report that increased TIMP-1 secretion and cytoskeletal rearrangements encompassing podosome dissolution are features of Toxoplasma-induced hypermigration of DCs with an impact on matrix degradation. Jointly, the data highlight how an obligate intracellular parasite orchestrates key regulatory cellular processes consistent with non-proteolytic amoeboid migration of the vehicle cells that facilitate its dissemination.

  • 104505.
    Öberg, Anette I.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    β-adrenergic signalling and novel effects in skeletal muscle2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Skeletal muscles have, due to their large mass, a big impact on the whole body metabolism. There are many signals that can regulate the functions of skeletal muscles and one such signal is activation of α- and β-adrenoceptors (α- and β-ARs) by epinephrine and norepinephrine. This activation leads to several effects which are examined in this thesis.

     

    Stimulation of β-AR on muscle cells induces glucose uptake, an event that both provides the muscle with energy and lowers the blood glucose levels. We discovered two key components in the β-ARs signal to glucose uptake: the transporter protein GLUT4 and the kinase mTOR, a molecule involved in several metabolic processes but not previously known to be activated by β-ARs.

     

    The classical second messenger downstream of β-ARs, cAMP, was surprisingly found to be only partly involved in the β-adrenergic glucose uptake. We also found that a molecule called GRK2 is very important for this glucose uptake.

     

    A novel effect of β-AR stimulation presented in this thesis is the inhibition of myosin II-dependent contractility in skeletal muscle cells. The intracellular pathway regulating this event was different from that regulating glucose uptake and involved both classical and novel molecules in the β-AR pathway.

     

    Another stimulus that we found to activate insulin-independent glucose uptake in skeletal muscle cells was the natural compound Shikonin. Shikonin increased glucose uptake in skeletal muscle cells via a calcium- and GLUT4-dependent mechanism and improved glucose homeostasis in diabetic rats.

     

    Taken together, we have identified new key molecules in the adrenergic signaling pathway as well as novel downstream effects. We conclude that glucose uptake in muscles can be activated by β-adrenergic stimulation or by Shikonin and that both treatments improves glucose homeostasis in diabetic animals. This knowledge can hopefully be used in the search for new drugs to combat type II diabetes.

  • 104506.
    Öberg, Anette I.
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Dehvari, Nodi
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Bengtsson, Tore
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    beta-Adrenergic Inhibition of Contractility in L6 Skeletal Muscle Cells2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 7, p. e22304-Article in journal (Refereed)
    Abstract [en]

    The beta-adrenoceptors (beta-ARs) control many cellular processes. Here, we show that beta-ARs inhibit calcium depletion-induced cell contractility and subsequent cell detachment of L6 skeletal muscle cells. The mechanism underlying the cell detachment inhibition was studied by using a quantitative cell detachment assay. We demonstrate that cell detachment induced by depletion of extracellular calcium is due to myosin-and ROCK-dependent contractility. The beta-AR inhibition of L6 skeletal muscle cell detachment was shown to be mediated by the beta(2)-AR and increased cAMP but was surprisingly not dependent on the classical downstream effectors PKA or Epac, nor was it dependent on PKG, PI3K or PKC. However, inhibition of potassium channels blocks the beta(2)-AR mediated effects. Furthermore, activation of potassium channels fully mimicked the results of beta(2)-AR activation. In conclusion, we present a novel finding that beta(2)-AR signaling inhibits contractility and thus cell detachment in L6 skeletal muscle cells by a cAMP and potassium channel dependent mechanism.

  • 104507.
    Öberg, Anette I.
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Sato, Masaaki
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Merlin, Jon
    Csikasz, Robert I.
    Sandström, Anna L.
    Hutchinson, Dana S.
    Summers, Roger J.
    Bengtsson, Tore
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Glucose uptake in skeletal muscle can be fully induced via the β2-adrenoceptor and GRK2 without cAMP-productionManuscript (preprint) (Other academic)
  • 104508.
    Öberg, Anette I.
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Yassin, Kamal
    Csikasz, Robert I.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Dehvari, Nodi
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Shabalina, Irina G.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Hutchinson, Dana S.
    Wilcke, Mona
    Östenson, Claes-Göran
    Bengtsson, Tore
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    Shikonin Increases Glucose Uptake in Skeletal Muscle Cells and Improves Plasma Glucose Levels in Diabetic Goto-Kakizaki Rats2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 7, p. e22510-Article in journal (Refereed)
    Abstract [en]

    Background: There is considerable interest in identifying compounds that can improve glucose homeostasis. Skeletal muscle, due to its large mass, is the principal organ for glucose disposal in the body and we have investigated here if shikonin, a naphthoquinone derived from the Chinese plant Lithospermum erythrorhizon, increases glucose uptake in skeletal muscle cells. Methodology/Principal Findings: Shikonin increases glucose uptake in L6 skeletal muscle myotubes, but does not phosphorylate Akt, indicating that in skeletal muscle cells its effect is medaited via a pathway distinct from that used for insulin-stimulated uptake. Furthermore we find no evidence for the involvement of AMP-activated protein kinase in shikonin induced glucose uptake. Shikonin increases the intracellular levels of calcium in these cells and this increase is necessary for shikonin-mediated glucose uptake. Furthermore, we found that shikonin stimulated the translocation of GLUT4 from intracellular vesicles to the cell surface in L6 myoblasts. The beneficial effect of shikonin on glucose uptake was investigated in vivo by measuring plasma glucose levels and insulin sensitivity in spontaneously diabetic Goto-Kakizaki rats. Treatment with shikonin (10 mg/kg intraperitoneally) once daily for 4 days significantly decreased plasma glucose levels. In an insulin sensitivity test (s.c. injection of 0.5 U/kg insulin), plasma glucose levels were significantly lower in the shikonin-treated rats. In conclusion, shikonin increases glucose uptake in muscle cells via an insulin-independent pathway dependent on calcium. Conclusions/Significance: Shikonin increases glucose uptake in skeletal muscle cells via an insulin-independent pathway dependent on calcium. The beneficial effects of shikonin on glucose metabolism, both in vitro and in vivo, show that the compound possesses properties that make it of considerable interest for developing novel treatment of type 2 diabetes.

  • 104509. Öberg, Britt-Marie
    et al.
    Närvänen, Anna-LiisaNäsman, ElisabetOlsson, ErikStockholm University, Faculty of Social Sciences, Department of Social Anthropology.
    Changing worlds and the ageing subject: dimensions in the study of ageing and later life2004Collection (editor) (Refereed)
  • 104510.
    Öberg, Cecilia
    Stockholm University, Faculty of Humanities, Department of Journalism, Media and Communication (JMK).
    "Forty is the new twenty": En analys av representationen av kvinnor i TV-serien Cougar Town2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Populärkulturella fenomen når ut till ett stort antal människor och representationen av olikasaker blir således viktig eftersom det kan avspegla hur människor uppfattarolika ting. Syftet med min uppsats är att undersöka representationen av de trekvinnliga karaktärerna, Jules, Ellie och Laurie, i tv-serien Cougar Town.

    De teoretiska begreppsom står till grund för min analys är bland annat, representation somdefinieras i boken Genus, medier ochmasskultur skriven av Linda Fagerström och Maria Nilson och som AnjaHirdman också behandlar i sin avhandling Tilltalandebilder. Vidare har jag använt mig av begreppet postfeminism som både Karen Boyle (Massmedia and Society, 2005)och Karen Ross (Gendered Media, 2010) skriver om i sina böcker.

    För att undersökarepresentationen av de olika kvinnliga karaktärerna i tv-serien använder jagmig av Keith Selby och Ron Cowderys bok Howto study television. I deras bok finns olika steg att gå igenom för attkritiskt granska television, jag har vidare valt att fokusera på den narrativaoch konstruktionsanalysen med fokus på mise-enscène och den icke verbala kommunikationen samt klädkoderna. För att kunnainrikta mig på den narrativa analysen har jag även använt mig av annanlitteratur som jag tillämpat på min metod- och analysdel.

    Genom att kritisktgranska tv- serien Cougar Town tydliggörsvissa stereotypiska drag som återkommer under de två analyserade avsnitten (The Pilot) och (Feel a whole lot better). Jules och hennes två vänner kan vidförsta anblicken ses som exempel på postfeministiska karaktärer som är självsäkra och karriärsinriktade. Dock efter att ha studerat olika sekvenser på ett merdjupgående sätt framkommer många så kallade ”typiska kvinnliga drag” som populärkulturella fenomen ofta tenderar att visa. 

  • 104511.
    Öberg, Christian
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Hammarsten, Philip
    Stockholm University, Faculty of Social Sciences, School of Business.
    Kassaflödesvärdering Vs Utdelningsbaseradvärdering: – en fallstudie av Delicard AB & SkiStar AB2005Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund och frågeställning: Att värdera ett företag har stort användningsområde, exempelvis vid försäljning av bolag, taxeringsärenden eller utlösen av delägarskap. Fler företag etablerar sig på denna marknad som aktörer som utför dessa tjänster. Adeqvat Företagsvärdering AB är en av dessa. På uppdrag av Adeqvat har frågan varit vilken värderingsmodell som är mest lämpad att använda vid företagsvärdering.

  • 104512. Öberg, Elisabet
    et al.
    Schäfer, Bernhard
    Geng, Xue-Li
    Pettersson, Jenny
    Hu, Qi
    Kritikos, Mikael
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Rasmussen, Torben
    Ott, Sascha
    C, C-Diacetylenic Phosphaalkenes as Heavy Diethynylethene Analogues2009In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 74, no 24, p. 9265-9273Article in journal (Refereed)
    Abstract [en]

    A series of C,C-diacetylenic phosphaalkenes 1be has been prepared from 1-chloropenta-1,2-dien-4-ynes 6be in a reaction with Mes*PCl2 (Mes* = 2,4,6-(tBu)3Ph) in the presence of LDA. Under identical conditions, isomeric butadiyne-substituted phosphaalkenes 2cf can be obtained from 3-chloropenta-1,4-diynes 5cf. The title compounds represent rare examples of diethynylethenes in which a constituting methylene has been replaced by a phosphorus center. The formation of both isomers can be rationalized by a common pathway that involves isomeric allenyllithium species. Spectroscopic, electrochemical, and theoretical investigations show that the phosphorus heteroatoms are an intrinsic part of the compounds’ π−systems and lead to decreased HOMO−LUMO gaps compared to those in all-carbon-based reference compounds.

  • 104513.
    Öberg, Erik
    Stockholm University, Faculty of Social Sciences, Department of Economics. Stockholm University, Faculty of Social Sciences, Institute for International Economic Studies.
    On Money and Consumption2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Price Level Determination When Tax Payments Are Required in Money. We formalize the idea that the price level can be determined by a requirement that taxes be paid in money. We show that if households have to pay a money tax of a fixed real value and the money supply is constant, there is a unique stationary price level, and a continuum of non-stationary deflationary equilibria. The non-stationary equilibria can be excluded if we introduce an arbitrarily lax borrowing constraint. Thus, in the basic model, tax requirements can uniquely determine the price level. When money has liquidity value, tax requirements can exclude self-fulfilling hyperinflations.

    The New Keynesian Transmission Mechanism: A Heterogeneous-Agent Perspective. We argue that a two-agent version of the standard New Keynesian model - where a "worker'' receives only labor income and a "capitalist'' only profit income - offers insights about how income inequality affects the monetary transmission mechanism. Under rigid prices, monetary policy has no effect on output as workers choose not to change their hours worked in response to wage movements. In the corresponding representative-agent model, in contrast, hours do rise after a monetary policy loosening due to a wealth effect on labor supply: profits fall, thus reducing the representative worker's income. If wages are rigid too, however, the monetary transmission mechanism is active and resembles that in the corresponding representative-agent model.

    Consumption Dynamics under Time-varying Unemployment Risk. We argue that adjustment frictions for durable goods generate a powerful amplification channel from fluctuations in unemployment risk to aggregate consumption demand. First, we use survey data to document that durable expenditures react strongly to increased unemployment risk, while the effect on nondurable expenditures is indistinguishable from zero. Second, we propose and calibrate a buffer-stock savings model that includes adjustment frictions for durable goods. Although not targeted in the calibration, we find that the model reproduces the semi-elasticities of expenditures to unemployment risk estimated in the data. Using the model, we find that the inclusion of adjustment frictions raises the aggregate demand response of durable goods to fluctuations in perceived unemployment risk by approximately 200 percent. Moreover, upon experiencing an adverse risk shock, the responsiveness of aggregate demand for durable goods to the interest rate and transitory income shocks is dampened.

    Consumption Dynamics under Time-varying Unemployment Risk: Evidence from Time Series Data. We investigate the relationship between consumption expenditures and unemployment risk using aggregate time series data for the US and ten EU countries. As a proxy for perceived unemployment risk, we use data on households' subjective expectations over the future unemployment rate. First, we employ a single-equation framework to test whether subjective unemployment expectations predict aggregate consumption growth when controlling for predicted aggregate income growth. Second, we exploit the timing of the survey interviews in relation to the publication of official statistics to isolate exogenous innovations to unemployment expectations in a small-scale vector autoregression. For the US, both methods suggest that there is a large effect of unemployment risk on aggregate consumption. For the ten EU countries, the evidence is mixed.

  • 104514.
    Öberg, Evelina
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Art and Design City Helsingfors: En studie av stadsbyggnadsprojektet Arabiastranden2007Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna uppsats har varit att studera på vilket sätt stadsbyggnadsprojektet Arabiastranden i Helsingfors kan ses som ett exempel på en generell trend inom samhällsplaneringen. Denna trend handlar om att använda sig av varumärken och estetiska uttryck i den byggda miljön för att marknadsföra och konkurrera på en global marknad. Uppsatsens fallstudieområde är stadsbyggnadsprojektet och stadsdelen Arabiastranden, som representerar konst, historia och design i Helsingforsregionens ambition att uppnå ett varumärke som en ”Art and Design City”. Metoden är baserad på personliga intervjuer, guidning, föreläsningar, planeringsdokument och litteratur. Teorier och koncept om informationssamhället, kreativa städer och den ”kreativa klassen” har använts för att diskutera en trend inom samhällsplaneringen som tillsammans med en global marknad, ny teknologi och livsstilar ställer krav på den fysiska miljön. Flera faktorer visar att Arabiastranden långsiktigt är ett exempel på en urban trend att marknadsföra städer med redan existerande värden i en allt högre global konkurrens.

  • 104515.
    Öberg, Fredrik
    Stockholm University, Faculty of Humanities, Department of French, Italian and Classical Languages.
    "...ad exaltacionem nominis venerabilis domine beate Katerine...": Fem Katarinamirakler ur Cod. Skokloster I 4° 152010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 104516.
    Öberg, Fredrik
    Stockholm University, Faculty of Humanities, Department of Romance Studies and Classics.
    Quasi quedam stella splendidissima: Katarinatexter ur Skoklosterhandskriften2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 104517. Öberg, Gunnar
    et al.
    Öberg, Bente
    Skilsmässa, sorg och förluster: kristerapi som alternativ till vårdnadsutredning : en effekt- och processtudie1979Doctoral thesis, monograph (Other academic)
  • 104518.
    Öberg, Helena
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Diatoms in Lake Duluti: Tracking Environmental Variability in Northern Tanzania during the Past 1000 Years2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The tropics are the regions which are least understood climatically and new data on past climate variability is necessary for reliable future modeling of climate change. This thesis contributes with new paleoenvironmental information from a small crater lake in northern Tanzania and provides an additional link between the integrated history of climate, environment and socioeconomic variability in tropical Africa. Pollen and diatom records from three short sediment cores and one piston core have been used to infer variations in past climate and environmental conditions. The chronological framework has been established by 210Pb and 137Cs activity profiles combined with AMS 14C dates on bulk sediment and Bayesian statistics have been used to construct the age-models. Together, the four cores cover approximately the last 1000 years. Modern limnological conditions (temperature, dissolved oxygen, pH and conductivity) and diatom assemblages from plankton, vegetation, stone scrape and near shore sediments have been surveyed to facilitate the paleoenvironmental interpretation. A detailed morphological analysis of Discostella species in Lake Duluti is presented. Frustule morphology of Discostella species have been examined using light microscope (LM) and scanning electron microscope (SEM) and led to the identification of a new variety; Discostella woltereckii v. minor Öberg, Risberg & Stabell. The multi-proxy record from the piston core infers dry conditions c. AD 1040–1470. Between c. AD 1470 and 1510 there are moist conditions with a lake high-stand centered on c. AD 1490. The period c. AD 1510–1640 is dry and between c. AD 1640 and 1790 there are indications of a continuously increase in moisture and higher lake levels, with a brief reversals in the 1660s. The results from the short cores indicate dry conditions from the late 19th century followed by a rapid rise in lake level sometime in the early 20th century. The observed trends show a good correlation with other paleoenvironmental data from East Africa. The results support the general hypothesis of regionally-wide dry conditions in the beginning of the last millennium and an inverse humidity pattern between western equatorial and eastern equatorial sites during the last centuries.

  • 104519.
    Öberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Andersen, Thorbjørn J.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Holmgren, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    A diatom record of recent environmental change in Lake Duluti, northern Tanzania2012In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 48, no 2, p. 401-416Article in journal (Refereed)
    Abstract [en]

    Lake Duluti is a small, topographically closed crater lake located on the flanks of Mt Meru, northern Tanzania. Analyses of diatoms in three short sediment cores and four modern samples from Lake Duluti were used to infer past environmental changes. 210Pb and 137Cs activity profiles combined with AMS 14C dates provide the chronological framework. Weak agreement between the 210Pb and 14C records, together with dating uncertainty, precludes construction of precise age models. The modern diatom flora, from plankton and three periphytic habitats, is dominated by Aulacoseira ambigua (Grunow) Simonsen, Gomphonema parvulum (Kützing) Grunow and Nitzschia amphibia Grunow. All three cores display similar stratigraphic succession, but the relative ratio of habitats represented by the diatoms varies substantially between cores. Diatoms indicate that the oldest part of the record is characterized by relatively low lake level and swampy vegetation. In the late nineteenth or early twentieth century there was a rapid lake level rise and the swamp turned into an open-water lake. High lake levels have prevailed since that time.

  • 104520.
    Öberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Norström, Elin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Ryner, Maria
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Holmgren, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dögg Eddudóttir, Sigrún
    Muzuka, Alfred
    Institute of Marine Science, University of Dar es Salaam.
    Environmental variability in northern Tanzania from c. AD 1000 to 1800, as inferred from diatoms and pollen in Lake DulutiManuscript (preprint) (Other academic)
    Abstract [en]

    Fossil pollen and diatoms have been analysed in a sediment sequence from a topographically closed crater lake in northern Tanzania(Lake Duluti), with the aim to reconstruct past changes in lake level and vegetation dynamics. The results contribute with a new paleoenvironmental record from equatorial Africacovering the period c. AD 1000 to AD 1800. Overall, the pollen and diatom records generate comparative stories of dry and wet periods. Dry conditions are inferred at c. AD 1040–1470, c. AD 1510–1640 and c. AD 1650–1670 with the lowest lake levels at c. AD 1260–1290 and AD 1600–1640. Wetter conditions occurred c. AD 1640–1650 and c. AD 1670–1790. The chronology is based on combined analyses of 210Pb activity and AMS 14C on bulk sediment, and a Bayesian model was applied to establish the age-depth relationship. The hydroclimatic record fromLakeDuluti shows good correlation with several East African lakes although precise comparison is hampered by dating uncertainties.

  • 104521.
    Öberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Norström, Elin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Ryner, Maria Malmström
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Holmgren, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eddudottir, Sigrun Dogg
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Andersen, Thorbjörn J.
    Muzuka, Alfred
    Environmental variability in northern Tanzania from AD 1000 to 1800, as inferred from diatoms and pollen in Lake Duluti2013In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 374, p. 230-241Article in journal (Refereed)
    Abstract [en]

    Fossil pollen and diatoms have been analyzed in a sediment sequence from a topographically closed crater lake in northern Tanzania (Lake Duluti), with the aim to reconstruct past changes in lake level and vegetation dynamics. The results provide a new paleoenvironmental record from equatorial Africa covering the period c. AD 1000 to AD 1800. Overall, the pollen and diatom records generate comparable stories of dry and wet periods. Dry conditions are inferred at c. AD 1040-1470, c. AD 1510-1640 and C. AD 1650-1670 with the lowest lake levels at c. AD 1260-1290 and AD 1600-1640. Wetter conditions occurred c. AD 1640-1650 and c. AD 1670-1790. The chronology is based on combined analyses of Pb-210 activity and AMS C-14 on bulk sediment, and a Bayesian model was applied to establish the age-depth relationship. The hydroclimatic record from Lake Duluti shows good correlation with several East African lakes in a centennial time perspective, although comparison of high frequency variability in the region is hampered by dating uncertainties.

  • 104522.
    Öberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Stabell, Bjørg
    Department of Geosciences, University of Oslo.
    Morphology, valve ultrastructure and stratigraphical variability of Discostella taxa in a tropical crater lake, northern Tanzania2009In: Diatom Research, ISSN 0269-249X, E-ISSN 2159-8347, Vol. 24, no 2, p. 341-356Article in journal (Refereed)
    Abstract [en]

    Morphological and ultrastructural variability of Discostella Houk et Klee (Bacillariophyceae) valves from a small crater lake in northern Tanzania have been examined under scanning electron microscope (SEM) and light microscope (LM). Three types of Discostella are described; Discostella woltereckii, as well as a small variety of D. woltereckii denoted Discostella woltereckii var. minor Öberg, Risberg et Stabell and an unidentified species, Discostella sp. The diatom record during the last ~100 years is dominated by D. woltereckii and D. woltereckii var. minor. The lithology and diatom stratigraphy of a 36 cm sediment surface core show a period of low lake level with extensive aquatic vegetation from around AD 1600. Sometime around AD 1900 there is a substantial rise in the lake water level indicated by an increase in euplanktonic Aulacoseira ambigua and facultative planktonic Discostella spp.

  • 104523.
    Öberg, Henrik
    Stockholm University, Faculty of Science, Department of Physics.
    Electronic structure and spectroscopy calculations in fuel cell catalysis2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents joint experimental and theoretical studies of surface phenomena at an electronic structure level in proton exchange membrane fuel cells (PEM-FC's).

    The fuel cell activity can be related to the oxygen reduction taking place at the cathodic surface through the oxygen reduction reaction (ORR). Under certain conditions the dissociative adsorption of O2 becomes the rate limiting reaction step and may therefore affect the overall fuel cell activity. Using core-level spectroscopy in terms of X-ray Photoemission Spectroscopy (XPS), the O2 dissociation barrier on Pt(111) has been determined and density functional theory (DFT) calculations reproduce the estimate well, using structure models that account for lateral adsorbate-adsorbate interactions, a finding that may have implications on the approach to calculate electronic structure properties of heterogeneous surface catalysis.

    Through a Brønsted-Evans-Polanyi (BEP) relation, the activation barrier for dissociation can be connected to the chemisorption energy of the atomic oxygen binding to the Pt surface. By affecting this energy, the activity of the fuel cell can be tuned; straining the Pt lattice weakens the O-Pt bond according to the Nørskov-Hammer d-band model which relates the adsorbate-substrate chemisorption energy to the position of the d-band center relative the Fermi level.

    X-ray Absorption (XAS) and Emission Spectroscopy (XES) have been used together with DFT to investigate the electronic structure effect in Pt due to strain, by depositing overlayers of Pt on Cu(111). The  d-band model can to some extent be employed to describe the strain effect - but the discrepancies between the calculations and the experiments remain an open question at present.

    Furthermore, the oxidation of the Pt(111) surface have been studied using XPS and XAS. DFT calculations support the experimental picture and suggest an oxidation resulting in an α-PtO2 type of surface-oxide.

  • 104524.
    Öberg, Henrik
    Stockholm University, Faculty of Science, Department of Physics.
    Surface reactions and chemical bonding in heterogeneous catalysis2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis summarizes studies which focus on addressing, using both theoretical and experimental methods, fundamental questions about surface phenomena, such as chemical reactions and bonding, related to processes in heterogeneous catalysis. The main focus is on the theoretical approach and this aspect of the results. The included articles are collected into three categories of which the first contains detailed studies of model systems in heterogeneous catalysis. For example, the trimerization of acetylene adsorbed on Cu(110) is measured using vibrational spectroscopy and modeled within the framework of Density Functional Theory (DFT) and quantitative agreement of the reaction barriers is obtained. In the second category, aspects of fuel cell catalysis are discussed. O2 dissociation is rate-limiting for the reduction of oxygen (ORR) under certain conditions and we find that adsorbate-adsorbate interactions are decisive when modeling this reaction step. Oxidation of Pt(111) (Pt is the electrocatalyst), which may alter the overall activity of the catalyst, is found to start via a PtO-like surface oxide while formation of α-PtO2 trilayers precedes bulk oxidation. When considering alternative catalyst materials for the ORR, their stability needs to be investigated in detail under realistic conditions. The Pt/Cu(111) skin alloy offers a promising candidate but segregation of Cu atoms to the surface is induced by O adsorption. This is confirmed by modeling oxygen x-ray emission (XES) and absorption spectra of the segregated system and near-perfect agreement with experiment is obtained when vibrational interference effects are included in the computed XES. The last category shows results from femtosecond laser measurements of processes involving CO on Ru(0001). Using free-electron x-ray laser experiments a precursor state to desorption is detected and also found in simulations if van der Waals effects are included. Resonant XES can be used to distinguish two different species of CO on the surface; vibrationally hot, chemisorbed CO and CO in the precursor state. Laser-induced CO oxidation on Ru(0001) is modeled and three competing mechanisms are found. Kinetic modeling reproduces the experiment qualitatively.

  • 104525.
    Öberg, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Anniyev, Toyli
    Vojvodic, Aleksandra
    Kaya, Sarp
    Ogasawara, Hirohito
    Friebel, Daniel
    Miller, Daniel J.
    Nordlund, Dennis
    Bergmann, Uwe
    Ljungberg, Mathias P.
    Stockholm University, Faculty of Science, Department of Physics.
    Abild-Pedersen, Frank
    Nilsson, Anders
    Stockholm University, Faculty of Science, Department of Physics. SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, Menlo Pk, CA 94025 USA.
    Pettersson, Lars G.M.
    Stockholm University, Faculty of Science, Department of Physics.
    Stability of Pt-Modified Cu(111) in the Presence of Oxygen and Its Implication on the Overall Electronic Structure2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 32, p. 16371-16380Article in journal (Refereed)
    Abstract [en]

    The electronic structure and stability of Cu(111)-hosted Pt overlayers with and without the presence of atomic oxygen have been studied by means of core-level spectroscopy and density functional theory (DFT). Because of lattice mismatch, Pt(111) overlayers grown on Cu(111) are compressively strained, and hard X-ray photoelectron spectroscopy together with Pt L-3-edge X-ray absorption spectroscopy (XAS) reveals a pronounced downshift of the Pt d-band owing to the increased overlap of the d-orbitals, an effect also reproduced theoretically. Exposure to oxygen severely alters the surface composition; the O-Cu binding energy largely exceeds that of O-Pt, and DFT calculations predict surface segregation of Cu atoms. Comparing the adsorbate electronic structure for O on unstrained Pt(111) with that of O on Pt-modified Cu(111) using O K-edge XAS and X-ray emission spectroscopy salient differences are observed and calculations show that Cu-segregation to the topmost layer is required to reproduce the measured spectra. It is proposed that O is binding in a hollow site constituted by at least two Cu atoms and that up to 75% of the Pt atoms migrate below the surface.

  • 104526.
    Öberg, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Gladh, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Dell'Angela, M.
    Anniyev, T.
    Beye, M.
    Coffee, R.
    Föhlisch, A.
    Katayama, T.
    Kaya, S.
    LaRue, J.
    Mögelhöj, A.
    Nordlund, D.
    Ogasawara, H.
    Schlotter, W. F.
    Sellberg, Jonas A.
    Stockholm University, Faculty of Science, Department of Physics. SLAC National Accelerator Laboratory, USA.
    Sorgenfrei, F.
    Turner, J. J.
    Wolf, M.
    Wurth, W.
    Öström, Henrik
    Stockholm University, Faculty of Science, Department of Physics.
    Nilsson, Anders
    Stockholm University, Faculty of Science, Department of Physics. SLAC National Accelerator Laboratory, USA.
    Nörskov, J. K.
    Pettersson, L. G. M.
    Stockholm University, Faculty of Science, Department of Physics.
    Optical laser-induced CO desorption from Ru(0001) monitored with a free-electron X-ray laser: DFT prediction and X-ray confirmation of a precursor state2015In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 640, p. 80-88Article in journal (Refereed)
    Abstract [en]

    We present density functional theory modeling of time-resolved optical pump/X-ray spectroscopic probe data of CO desorption from Ru(0001). The BEEF van der Waals functional predicts a weakly bound state as a precursor to desorption. The optical pump leads to a near-instantaneous (<100 fs) increase of the electronic temperature to nearly 7000 K. The temperature evolution and energy transfer between electrons, substrate phonons and adsorbate is described by the two-temperature model and found to equilibrate on a timescale of a few picoseconds to an elevated local temperature of similar to 2000K. Estimating the free energy based on the computed potential of mean force along the desorption path, we find an entropic barrier to desorption (and by time-reversal also to adsorption). This entropic barrier separates the chemisorbed and precursor states, and becomes significant at the elevated temperature of the experiment (similar to 1.4 eV at 2000 K). Experimental pump-probe X-ray absorption/X-ray emission spectroscopy indicates population of a precursor state to desorption upon laser-excitation of the system (Dell'Angela et al., 2013). Computing spectra along the desorption path confirms the picture of a weakly bound transient state arising from ultrafast heating of the metal substrate.

  • 104527.
    Öberg, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Gladh, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Marks, Kess
    Stockholm University, Faculty of Science, Department of Physics.
    Ogasawara, H.
    Nilsson, Anders
    Stockholm University, Faculty of Science, Department of Physics. SLAC National Accelerator Laboratory, USA.
    Pettersson, Lars G. M.
    Stockholm University, Faculty of Science, Department of Physics.
    Östrom, Henrik
    Stockholm University, Faculty of Science, Department of Physics.
    Indication of non-thermal contribution to visible femtosecond laser-induced CO oxidation on Ru(0001)2015In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 143, no 7, article id 074701Article in journal (Refereed)
    Abstract [en]

    We studied CO oxidation on Ru(0001) induced by 400 nm and 800 nm femtosecond laser pulses where we find a branching ratio between CO oxidation and desorption of 1: 9 and 1: 31, respectively, showing higher selectivity towards CO oxidation for the shorter wavelength excitation. Activation energies computed with density functional theory show discrepancies with values extracted from the experiments, indicating both a mixture between different adsorbed phases and importance of non-adiabatic effects on the effective barrier for oxidation. We simulated the reactions using kinetic modeling based on the two-temperature model of laser-induced energy transfer in the substrate combined with a friction model for the coupling to adsorbate vibrations. This model gives an overall good agreement with experiment except for the substantial difference in yield ratio between CO oxidation and desorption at 400 nm and 800 nm. However, including also the initial, non-thermal effect of electrons transiently excited into antibonding states of the O-Ru bond yielded good agreement with all experimental results.

  • 104528.
    Öberg, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Gladh, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Pettersson, Lars G M
    Stockholm University, Faculty of Science, Department of Physics.
    Öström, Henrik
    Stockholm University, Faculty of Science, Department of Physics.
    CO oxidation on Ru(0001) modeled from first-principles and femtosecond laser measurementsManuscript (preprint) (Other academic)
  • 104529.
    Öberg, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Nestsiarenka, Yuliya
    Stockholm University, Faculty of Science, Department of Physics.
    Matsuda, A.
    Stockholm University, Faculty of Science, Department of Physics.
    Gladh, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Hansson, Tony
    Stockholm University, Faculty of Science, Department of Physics.
    Pettersson, Lars G.M.
    Stockholm University, Faculty of Science, Department of Physics.
    Öström, Henrik
    Stockholm University, Faculty of Science, Department of Physics.
    Adsorption and Cyclotrimerization Kinetics of C2H2 at a Cu(110) Surface2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 17, p. 9550-9560Article in journal (Refereed)
    Abstract [en]

    The kinetics of acetylene adsorption and cyclotrimerization was studied by vibrational sum-frequency generation spectroscopy (SFG) and density functional theory (DFT) calculations. At low temperature, SFG shows two resonances corresponding to acetylene adsorbed in two different sites. Upon heating, two new vibrational resonances appear. We interpret these resonances as being due to C2H2 island formation and adsorbed C4H4, which is the intermediate in the subsequent cyclotrimerization reaction to form benzene. A kinetic model is applied, which allows determination of the relevant activation barriers. The barrier for C2H2 diffusion is determined to be 43 +/- 1 kJ/mol. The activation barrier for formation of the C4H4 intermediate is found to be 84 +/- 6 kJ/mol and the barrier for benzene formation 5 +/- 3 kJ/mol lower. Barriers to diffusion and formation of C4H4 and C6H6 obtained from DFT calculations are in quantitative agreement with the experiments once the locally high coverage in C2H2 islands is included.

  • 104530.
    Öberg, Jan
    Stockholm University, Faculty of Humanities.
    Cena Trimalchionis1999Book (Other academic)
  • 104531.
    Öberg, Jan
    Stockholm University, Faculty of Humanities.
    Chronica regni Gothorum [av] Ericus Olai: 2, Prolegomena und Indizes1995Book (Other academic)
  • 104532.
    Öberg, Jan
    Stockholm University, Faculty of Humanities.
    Formularia Lincopensia: zwei spätmittelalterliche Briefsteller aus dem Bistum Linköping (Cod. Upsal. C 204) : textkritische Gesamtausgabe mit Einleitung und Register1997Book (Other academic)
  • 104533.
    Öberg, Jan
    Stockholm University, Faculty of Humanities.
    Notice et extraits du manuscrit Q 19 (XVIe s.) de Strängnäs.1968Book (Other academic)
  • 104534.
    Öberg, Jan
    Stockholm University, Faculty of Humanities.
    Serlon de Wilton poèmes latins1965Doctoral thesis, monograph (Other academic)
  • 104535.
    Öberg, Jan
    et al.
    Stockholm University, Faculty of Humanities, Department of French, Italian and Classical Languages. Klassiska språk.
    Kihlman, ErikaStockholm University, Faculty of Humanities, Department of French, Italian and Classical Languages. Klassiska språk.Melin, PiaDepartment of the History of Art.
    Den mångsidige målaren: vidgade perspektiv på Albertus Pictors bild- och textvärld.: Föredrag från ett symposium vid Stockholms universitet oktober 20052007Collection (editor) (Other academic)
  • 104536.
    Öberg, Jesper
    Stockholm University, Faculty of Law, Department of Law.
    Mervärdesbeskattning vid obestånd2000Doctoral thesis, monograph (Other academic)
  • 104537.
    Öberg, Johan
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Gloudemans, Henrik
    Stockholm University, Faculty of Social Sciences, School of Business.
    Ehnar, Magnus
    Stockholm University, Faculty of Social Sciences, School of Business.
    Skuldsättningsgrader - En jämförelse mellan O-listans IT-bolag och A-listan2000Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats går i huvudsak ut på att undersöka kapitalstrukturen bland IT-bolag på O-listan samt jämföra dessa med A-listans genomsnitt.

  • 104538.
    Öberg, Johanna
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Hernvall, Patrik
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Participatory Design with Teachers: Designing the Workshops2016In: Proceedings of the 5th International Conference on Designs for Learning / [ed] Anne-Mette Nortvig, Birgitte Holm Sørensen, Morten Misfeldt, Rikke Ørngreen, Benjamin Allsopp, Birgitte Henningsen, Heidi Hautopp, Aalborg: Aalborg University Press , 2016, p. 269-282Conference paper (Refereed)
    Abstract [en]

    Participatory methods are becoming more and more commonly used in social research. These methods are used in a variety of research fields, such as; Human Computer Interaction, Education, Public Health, Civic Engagement, and so on. Participatory methods are valuable because they utilize the knowledge and experience of all the collaborators. The paper focuses on the participatory design process performed with a group of junior high school teachers and the conditions for the development of a pedagogical practice. The process, which aimed for supporting increased pupil participation, was fuelled by the development of a pedagogical model at four workshops during 2015 (April to September). Main findings from the analysis of these workshops propose that participatory design as an action research method support the appropriation of new pedagogical approaches in general, and the understanding of the possibilities of supporting pupil participation in formal education in particular.

  • 104539.
    Öberg, Johanna
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Nouri, Jalal
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Cerratto-Pargman, Teresa
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Aghaee, Nam
    Students' perspective on the use of digital tools for participation in the school/classroom2018In: EDULEARN18: Proceedings, The International Academy of Technology, Education and Development, 2018, p. 5291-5297Conference paper (Refereed)
  • 104540.
    Öberg, Louise
    Stockholm University, Faculty of Social Sciences, Department of Special Education.
    Den stora utmaningen: Gymnasielärares uppfattning och upplevelse av arbetet med extra anpassning och särskilt stöd2018Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Trots de goda intentioner som finns i skolans styrdokument dras gymnasieskolan med en rad problemsom berör elever i behov av stöd. Problem som till exempel att eleven själv förväntas ta ansvar för sina studier, otydligheter i regelverket kring extra anpassningar och särskilt stöd samt lärarens inställning till elever i behov av stöd, gör att skolan har svårt att vara en skola för alla. Syftet med denna studie är att undersöka gymnasielärares uppfattning och upplevelse av att genomföra extra anpassningar och särskilt stöd. Genom semistrukturerade intervjuer med åtta gymnasielärare från sex olika skolor har datamaterial samlats in som sedan analyserats med hjälp av tematisk analys. I analysen synliggörs tre teman, identifiering av elever i behov av stöd, försvårande faktorer i arbetet med extra anpassningar och särskilt stöd samt främjande faktorer i arbetet med extra anpassningar och särskilt stöd. I resultatet framkommer att arbetet med extra anpassningar och särskilt stöd ses som komplext. Det är varje lärares uppdrag att anpassa sin undervisning så att den möter alla elevers olika behov men det är förknippat med svårigheter. De största hindren är enligt lärarna att det är för stora grupper och att tiden inte räcker till för att både planera och utföra extra anpassningar och särskilt stöd. Det blir tydligt att bland de lärare som anser att de inte får tillräckliga förutsättningar för arbetet med extra anpassningar och särskilt stöd så saknas ett nära samarbete med skolans ledning. Resultatet visar också på vilka faktorer som lärarna upplever som förutsättningar för att lyckas med uppdraget. Där framhålls samarbete med elevens mentor, kollegor och elevhälsa som den allra viktigaste framgångsfaktorn föratt lyckas med extra anpassningar och särskilt stöd. De resultat som framkommer får betydelse för det specialpedagogiska yrket då det belyser både hinder och förutsättningar från lärarens perspektiv. Resultatet tyder också på att ett systematiskt arbete kring extra anpassning och särskilt stöd motverkar den osäkerhet många oerfarna lärare känner och där har en specialpedagog en viktig roll att spela.

  • 104541.
    Öberg, Marcus
    Stockholm University, Faculty of Humanities, Department of English.
    Belief and Religion in Terry Pratchett’s The Hogfather2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Being widely known as comedy fantasy, Terry Pratchett’s Discworld series has been highly regarded by fans and critics alike. While known for their comic tone, Pratchett’s novels have also dealt with grave topics, such as the power of belief and the notion that gods are created, destroyed and made relevant through belief and worship. Yet, there is a distinct gap in academic literature investigating Pratchett’s ideas concerning the nature of both belief and religion. Although Amanda Cockrell has touched upon similar subjects, this paper will address the nature of belief and religion in the Discworld further, by focusing on the novel The Hogfather. I argue that The Hogfather suggests humans are capable of giving meaning to the world around them through the power of belief, and that religion is created by humans to make the world around them more meaningful. In Pratchett’s Discworld, humans have created gods to make sense of what they cannot understand and in this way, they try to bring meaning to the world around them. Furthermore, I argue that The Hogfather presents a case for the importance of religious belief in a modern, secularised world. By presenting “Hogswatch”—the Discworld equivalent of Christmas—as a satire of belief and tradition, Pratchett suggests that, in the end, both secular and religious worldviews should co-exist.

  • 104542. Öberg, Peter
    et al.
    Bildtgård, Torbjörn
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    New sexual relationships in later life: The case of late modern Sweden2013In: The Gerontologist, ISSN 0016-9013, E-ISSN 1758-5341, Vol. 53, no S1Article in journal (Other academic)
    Abstract [en]

    It is often argued that in late modernity sex has escaped its reproductive cage and people form pure relationships, based on mutual satisfaction. Ironically, although older people are per definition non-reproductive, and thus in a position to form pure relationships, they have often been neglected in studies on sexuality. In this paper we present results from a qualitative interview study with a strategic sample of 28 63–91 year old Swedes currently dating or in a heterosexual relationship (married, cohabiting, LAT) initiated 60+. The interviews revealed a clear normative change: The majority reported a definite ban on pre-marital sex when growing up. All had experienced the 1960s sexual liberation, either directly or from the inside of a marriage. Today, these liberal attitudes seem to encompass later life. None of our respondents reported negative reactions from family or friends for initializing new sexual relationships. With two exceptions all informants in new relationships were sexually active, and sexual attraction had been a precondition for the relationship. Sexuality had changed focus: from intercourse to other forms of intimacy, partly aided by a change in sexual functionality. Many informants had interpreted sexual decline as “natural” and age-related in former relationships, but re-discovered sexuality with their new partner. Some female informants had been worried about their body’s beauty or functionality which had led them to re-initiate relationships with former “safe” partners. The qualitative results will be critically discussed in the light of a representative survey of 3000 Swedes, 60– 90 year old (data just collected).

  • 104543.
    Öberg, Rickard
    Stockholm University, Faculty of Humanities, Department of History.
    Varthän flyr vi, mina tappra män?: En komparativ studie av militärideologi i Vegetius och Ammianus Marcellinus texter2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study is situated between the disciplines of military history and the history of ideas. It focuses on two late Roman writers; the bureaucrat Vegetius and the historian Ammianus Marcellinus. Drawing on linguistic methodology and a theory of ideology formulated by the Swedish political scientist Herbert Tingsten, this is the first comprehensive and comparative study of these two important sources of information on the late Roman military. The purpose of the study has been to elucidate and explain ideological differences and similarities between the two figures. Previous research suggests that Vegetius’ De Re Militari is a less trustworthy source given its author’s lack of military experience and his reliance on earlier written sources. By comparing it with Ammianus’ Res Gestae, a source often attributed greater credibility, this study hoped to demonstrate significant similarities that would warrant a re-evaluation of Vegetius’ source value. However, the conclusion drawn from the comparative examination of these two texts is that Ammianus and Vegetius did not share a common military ideology and that there are no grounds for a profound re-evaluation of Vegetius’ credibility.

  • 104544. Öborn, Ingrid
    et al.
    Bengtsson, Jan
    Hedenus, Fredrik
    Rydhmer, Lotta
    Stenström, Maria
    Vrede, Katarina
    Westin, Charles
    Stockholm University, Faculty of Social Sciences, Department of Social Anthropology.
    Magnusson, Ulf
    Scenario Development as a Basis for Formulating a Research Program on Future Agriculture: A Methodological Approach2013In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 42, no 7, p. 823-839Article, review/survey (Refereed)
    Abstract [en]

    To increase the awareness of society to the challenges of global food security, we developed five contrasting global and European scenarios for 2050 and used these to identify important issues for future agricultural research. Using a scenario development method known as morphological analysis, scenarios were constructed that took economic, political, technical, and environmental factors into account. With the scenarios as a starting point future challenges were discussed and research issues and questions were identified in an interactive process with stakeholders and researchers. Based on the outcome of this process, six socioeconomic and biophysical overarching challenges for future agricultural were formulated and related research issues identified. The outcome was compared with research priorities generated in five other research programs. In comparison, our research questions focus more on societal values and the role of consumers in influencing agricultural production, as well as on policy formulation and resolving conflicting goals, areas that are presently under-represented in agricultural research. The partly new and more interdisciplinary research priorities identified in Future Agriculture compared to other programs analyzed are likely a result of the methodological approach used, combining scenarios and interaction between stakeholders and researchers.

  • 104545.
    Öbrink, Charlott
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Damm, Jenny
    Stockholm University, Faculty of Social Sciences, School of Business.
    Corporate branding and the implications of emotional values2001Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim with this thesis was to explore the process of corporate brandin and the implications emotional values may have on this process. With this aim, there is in a hermeneutic philosophy way an aspiration to create an understanding of the subject. The empirical results are gained through qualitative interviews. The understanding that has been reached in this thesis are among others that one of the characteristics of a corporate brand is that the employees' values have a more complex influence on the brand. Emotional values make the brand distinct and create customer - and employee loyalty throuhg creating a feeling for the brand. The result of this is that in order to be able to build a strong corporate brand, the corporation needs to consider not only the functional values within the corporation but also its emotional values.

  • 104546.
    Öbrink, Charlott
    et al.
    Stockholm University, Faculty of Social Sciences, School of Business.
    Damm, Jenny
    Stockholm University, Faculty of Social Sciences, School of Business.
    Positionering: En utredning av framgångfaktorer och fallgropar vid positionering av konsumentföretag2001Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med uppsatsen är att identifiera, utreda och skapa förståelse för ett antal framgångsfaktorer och fallgropar vid positionering av konsument företag. För att uppfylla syftet har ett antal konsulter inom marknadsföring, positionering och corporate design intervjuats. Det har i uppsatsen framkommit att för en framgångsrik positionering krävs kunskap om konsumenter, konkurrenter, och företagets identitet.

  • 104547.
    Öckert, Björn
    Stockholm University, Faculty of Social Sciences, The Swedish Institute for Social Research (SOFI).
    Effects of higher education and the role of admission selection2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Study I Using Admission Selection Rules to Estimate the University Earnings Premium - A Regression-Discontinuity Design

    This study estimates the earnings premiums for university admission and graduation, using unique data from the admission selection process. Applicants and non-applicants for university in Sweden in 1982 are studied in terms of earnings in 1996. Admitted applicants are compared with four groups of non-admitted individuals. The choice of comparison group proves crucial when estimating the admission earnings premium. A comparison between admitted applicants and a random sample of non-applicants yields a significantly higher admission effect than a similar comparison using withdrawals or screen-outs. When the admission selection variables are added to the model, the effect of admission is completely eliminated. When admitted applicants are decomposed into no-shows, dropouts and completers, the same pattern emerges as in the case of the effect of admission. The university completion premium falls from 18 per cent when non-applicants provide the comparison group to 5 per cent when screen-outs are used instead and admission selection variables are controlled for. Hence, two thirds of the estimated effects are attributable to unobserved differences, while only one third can be seen as a causal effect. In order to find unbiased estimates of the effects of different programmes or interventions, information about all the selection mechanisms seems to be crucial.

    Study II Estimating the Return to Higher Education Using a Social Experiment

    Applicants for a university education in Sweden who possess equal qualifications have been subject to selection by lottery, i.e. there has been a social experiment at the margin. This study uses a unique data set of over 1,600 individuals who in the autumn of 1982 were subject to randomized admission to university. Annual earnings between 1982 and 1996 are used to compute lifetime earnings. To adjust for dropout and substitution bias in the estimated treatment effects, two new estimators are proposed. They allow for non-zero effects of partial treatment and for alternative treatment for all treatment group members.

    The choice of estimator proves crucial. If no adjustments are made, only about half the estimated returns to university training are positive. Accounting for dropout bias raises the estimates. The result is not sensitive to alternative identifying assumptions. When the earnings differences between treatment group and control group members are adjusted for both dropout bias and substitution bias, the estimated effects becomes much higher. Allowing all treatment group members to receive alternative treatment reduces the estimates substantially. The estimates suggest that the internal rate of return to completed university education is about 20 per cent, significantly different from zero.

    Study IIIDoes Pre-University Background Matter?

    This study analyses the completion probability and the effects of university on labour market performance for groups with different pre-university background. The data includes detailed information on the admission selection process for most applicants to university education in Sweden in 1982. The results reveal considerable heterogeneity in the probability of obtaining a degree and the effect of university studies on labour market performance. Applicants with long upper secondary schooling are more likely to graduate from university than other students are. The best indicator of degree completion is grade point averages from upper secondary school and the field of educational interest. It is interesting to note that age is negatively related to student performance.

    In terms of employment and earnings, returning adults have more to gain from being admitted to university or receiving a degree there than students with any other pre-university background. Hence, the pay-off for allowing individuals a 'second chance' seems substantial. Another finding is that completers generally do better than no-shows, who in turn do better than dropouts. Further, the effects of attending university on employment and earnings are small for all groups, particularly for students with short upper secondary schooling. The return to a completed programme for students with long upper secondary schooling is estimated at 5 per cent. 

  • 104548.
    Öcut, Belkiz
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Vägen till akademisk utbildning: En kvantitativ studie om hur etnicitet, kulturellt kapital och klass påverkar individens möjligheter till högre studier2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrunden till denna uppsats är ett intresse för att undersöka huruvida skillnader i utbildningsnivå kan förklaras utifrån etnicitet, kulturellt kapital och klass. Med utgångspunkt i litteraturen finns det förklaringar som menar att kulturellt kapital är en begränsad resurs i samhället och alla har inte de kulturella förutsättningar som gör det “enklare” för människor att satsa på utbildning för sig själva och sina framtida barn. Det förekommer även förklaringar som menar att beroende på föräldrarnas etniska och socioekonomiska ursprung uppstår det olikheter utbildningsprocessen som påverkar både livschanser och beteenden som i sin tur kan leda till att individer inte kan leva upp till sin fulla potential.I studien har kvantitativ metod använts och mätningar har gjorts med data från Levnadsnivåundersökningen (LNU) 2010. Uppsatsen utgår från två hypoteser och analyserar stödet för följande hypoteser: (1) Det finns skillnader i utbildning mellan personer födda i Sverige jämfört med personer som inte är det, (2) Dessa skillnader kan förklaras med socioekonomiska resurser och kulturellt kapital. I resultatet kan man se att den första hypotesen inte visar ett inget signifikant samband mellan skillnader etnicitet (individer med utländsk bakgrund och individer med svenskfödda föräldrar) och utbildning. Resultatet visar vidare att hypotesen 2 delvis stämmer. Socioekonomiska resurser och kulturellt kapital påverkar till en viss del skillnader som uppstår i utbildning, men enbart socioekonomiska resurser och kulturellt kapital kan inte förklara skillnader i utbildningsval mellan individer med utländsk bakgrund och individer med svenskfödda föräldrar.

  • 104549.
    Ödalen, Malin
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nycander, Jonas
    Stockholm University, Faculty of Science, Department of Meteorology .
    Oliver, Kevin I. C.
    Brodeau, Laurent
    Stockholm University, Faculty of Science, Department of Meteorology . Barcelona Supercomputer Center, Spain.
    Ridgwell, Andy
    The influence of the ocean circulation state on ocean carbon storage and CO2 drawdown potential in an Earth system model2018In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 15, no 5, p. 1367-1393Article in journal (Refereed)
    Abstract [en]

    During the four most recent glacial cycles, atmospheric CO2 during glacial maxima has been lowered by about 90-100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air-sea CO2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO2 disequilibrium component. We also relate these contributions to differences in the strength of the ocean overturning circulation. Depending on which ocean forcing parameter is tuned, the origin of the change in carbon storage is different. When wind stress or ocean diapycnal diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean isopycnal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Despite this complexity, we obtain a negative linear relationship between total ocean carbon and the combined strength of the northern and southern overturning cells. This relationship is robust to different reservoirs dominating the response to different forcing mechanisms. Finally, we conduct a drawdown experiment in which we investigate the capacity for increased carbon storage by artificially maximising the efficiency of the biological pump in our ensemble members. We conclude that different initial states for an ocean model result in different capacities for ocean carbon storage due to differences in the ocean circulation state and the origin of the carbon in the initial ocean carbon reservoir. This could explain why it is difficult to achieve comparable responses of the ocean carbon pumps in model intercomparison studies in which the initial states vary between models. We show that this effect of the initial state is quantifiable. The drawdown experiment highlights the importance of the strength of the biological pump in the control state for model studies of increased biological efficiency.

  • 104550.
    Ödalen, Malin
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nycander, Jonas
    Stockholm University, Faculty of Science, Department of Meteorology .
    Ridgwell, Andy
    Oliver, Kevin I. C.
    Peterson, Carlye D.
    Nilsson, Johan
    Stockholm University, Faculty of Science, Department of Meteorology .
    Variable C/P composition of organic production and its effect on ocean carbon storage in glacial model simulations2019In: Biogeosciences Discussions, ISSN 1810-6277, E-ISSN 1810-6285Article in journal (Other academic)
    Abstract [en]

    During the four most recent glacial maxima, atmospheric CO2 has been lowered by about 90--100 ppm with respect to interglacial concentrations. It is likely that most of the atmospheric CO2 deficit was stored in the ocean. Changes of the biological pump, which are related to the efficiency of the biological carbon uptake in the surface ocean and/or of the export of organic carbon to the deep ocean, have been proposed as a key mechanism for the increased glacial oceanic CO2 storage. The biological pump is strongly constrained by the amount of available surface nutrients. In models, it is generally assumed that the ratio between elemental nutrients, e.g. phosphorus, and carbon (C/P ratio) in organic material is fixed according to the classical Redfield ratio. The constant Redfield ratio appears to hold approximately when averaged over basin scales, but observations document highly variable C/P ratios on regional scales and between species. If the C/P ratio decreases when nutrient availability is scarce, as observations suggest, this has the potential to further increase glacial oceanic CO2 storage in response to changes in surface nutrient distributions. In the present study, we perform a sensitivity study to test how a phosphate--concentration dependent C/P ratio influences the oceanic CO2 storage in an Earth system model of intermediate complexity (cGENIE). We carry out simulations of glacial--like changes in albedo, radiative forcing, wind--forced circulation, remineralisation depth of organic matter, and mineral dust deposition. Specifically, we compare model versions with with the classical constant Redfield ratio and an observationally-motivated variable C/P ratio, in which the carbon uptake increases with decreasing phosphate concentration. While a flexible C/P ratio does not impact the model's ability to simulate benthic d13C patterns seen in observational data, our results indicate that, in production of organic matter, flexible C/P can further increase the oceanic storage of CO2 in glacial model simulations. Past and future changes in the C/P ratio thus have implications for correctly projecting changes in oceanic carbon storage in glacial-to-interglacial transitions as well as in the present context of increasing atmospheric CO2 concentrations.

2088208920902091209220932094 104501 - 104550 of 105609
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf