| 1. |
- Bastos Lima, Mairon G., et al.
(författare)
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Large-scale collective action to avoid an Amazon tipping point - key actors and interventions
- 2021
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Ingår i: Current Research in Environmental Sustainability. - : Elsevier BV. - 2666-0490. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The destruction of the Amazon is a major global environmental issue, not only because of greenhouse gas emissions or direct impacts on biodiversity and livelihoods, but also due to the forest's role as a tipping element in the Earth System. With nearly a fifth of the Amazon already lost, there are already signs of an imminent forest dieback process that risks transforming much of the rainforest into a drier ecosystem, with climatic implications across the globe. There is a large body of literature on the underlying drivers of Amazon deforestation. However, insufficient attention has been paid to the behavioral and institutional microfoundations of change. Fundamental issues concerning cooperation, as well as the mechanisms facilitating or hampering such actions, can play a much more central role in attempts to unravel and address Amazon deforestation. We thus present the issue of preventing the Amazon biome from crossing a biophysical tipping point as a large-scale collective action problem. Drawing from collective action theory, we apply a novel analytical framework on Amazon conservation, identifying six variables that synthesize relevant collective action stressors and facilitators: information, accountability, harmony of interests, horizontal trust, knowledge about consequences, and sense of responsibility. Drawing upon literature and data, we assess Amazon deforestation and conservation through our heuristic lens, showing that while growing transparency has made information availability a collective action facilitator, lack of accountability, distrust among actors, and little sense of responsibility for halting deforestation remain key stressors. We finalize by discussing interventions that can help break the gridlock.
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| 2. |
- Hofving, Tobias, 1989, et al.
(författare)
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SMAD4 haploinsufficiency in small intestinal neuroendocrine tumors
- 2021
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with small intestinal neuroendocrine tumors (SINETs) frequently present with lymph node and liver metastases at the time of diagnosis, but the molecular changes that lead to the progression of these tumors are largely unknown. Sequencing studies have only identified recurrent point mutations at low frequencies with CDKN1B being the most common harboring heterozygous mutations in less than 10% of all tumors. Although SINETs are genetically stable tumors with a low frequency of point mutations and indels, they often harbor recurrent hemizygous copy number alterations (CNAs) yet the functional implications of these CNA are unclear. Methods: Utilizing comparative genomic hybridization (CGH) arrays we analyzed the CNA profile of 131 SINETs from 117 patients. Two tumor suppressor genes and corresponding proteins i.e. SMAD4, and CDKN1B, were further characterized using a tissue microarray (TMA) with 846 SINETs. Immunohistochemistry (IHC) was used to quantify protein expression in TMA samples and this was correlated with chromosome number evaluated with fluorescent in-situ hybridization (FISH). Intestinal tissue from a Smad4+/− mouse model was used to detect entero-endocrine cell hyperplasia with IHC. Results: Analyzing the CGH arrays we found loss of chromosome 18q and SMAD4 in 71% of SINETs and that focal loss of chromosome 12 affecting the CDKN1B was present in 9.4% of SINETs. No homozygous loss of chromosome 18 was detected. Hemizygous loss of SMAD4, but not CDKN1B, significantly correlated with reduced protein levels but hemizygous loss of SMAD4 did not induce entero-endocrine cell hyperplasia in the Smad4+/− mouse model. In addition, patients with low SMAD4 protein expression in primary tumors more often presented with metastatic disease. Conclusions: Hemizygous loss of chromosome 18q and the SMAD4 gene is the most common genetic event in SINETs and our results suggests that this could influence SMAD4 protein expression and spread of metastases. Although SMAD4 haploinsufficiency alone did not induce tumor initiation, loss of chromosome 18 could represent an evolutionary advantage in SINETs explaining the high prevalence of this aberration. Functional consequences of reduced SMAD4 protein levels could hypothetically be a potential mechanism as to why loss of chromosome 18 appears to be clonally selected in SINETs.
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| 3. |
- Kmoch, Laura, 1987, et al.
(författare)
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Access mapping highlights risks from land reform in upland Myanmar
- 2021
-
Ingår i: Journal of Land Use Science. - 1747-4248 .- 1747-423X. ; 16:1, s. 34-54
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Tidskriftsartikel (refereegranskat)abstract
- Secure land access is vital for Myanmar's upland households, who rely on crops and forests to meet their subsistence needs. But recent land reforms threaten to undermine customary tenure and land-use practices in Myanmar. This paper combines income accounting methods with access theory to assess how new legislation may affect four Chin communities in the country's north-west. Our assessment of 94 households' land-access mechanisms and economic benefits from different types of land reveals existing land-access inequalities among Chin households and demonstrates communities' continued dependence on environmental resources, especially those from swidden fields, home gardens and forests. A majority of households would lose all of their land-derived income, if they were denied access to communities' customarily governed land, e.g., under the Vacant, Fallow and Virgin Land Management Law. Policy stakeholders should therefore intervene, to alleviate land-access inequalities among Chin households and to direct Myanmar's land-system dynamics onto more just development trajectories.
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| 4. |
- Kmoch, Laura, 1987, et al.
(författare)
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Cyclone Komen’s aftermath: Local knowledge shows how poverty and inequalities fuel climate risk in western Myanmar
- 2021
-
Ingår i: Regional Environmental Change. - : Springer Science and Business Media LLC. - 1436-378X .- 1436-3798. ; 21:4
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Tidskriftsartikel (refereegranskat)abstract
- Cyclones and other extreme events exert increasing pressure on South-East Asia’s societies and put smallholder farmers at risk. Here, we draw on participatory causal-diagramming workshops, interviews and survey data, to provide contextually grounded knowledge about rural communities’ exposure and vulnerability to climate-related hazards in western Myanmar. By tracing how the 2015 cyclone Komen led to a prolonged humanitarian disaster, we show that climate-related risks in this area arise from the complex interplay of households’ pre-existing vulnerabilities, persistent farming challenges, extensive disasters and cascading effects, which disparately affect lowland and upland communities. The different household strata’s dissimilar vulnerabilities vis-à-vis Komen’s impacts were rooted in the distinct exposure of their production systems to landslides and floods. Pre-existing land-access barriers, land-degradation processes, climatic stressors, agricultural pests and diseases, and chronic lack of assets and food insecurity further mediated households’ vulnerability. Relief interventions did not stop the disaster’s escalation, although this could have been achieved with early technical and material assistance to address the cyclone’s impacts on farmers’ land. Targeted aid for households facing imminent food insecurity or debt crisis could have lessened engagement in precarious coping strategies and distress migration. A diversification of households’ livelihood and land-use practices and increased redundancies of critical assets and infrastructure could help to mitigate future cyclone-triggered disasters. By demonstrating the strengths of local knowledge approaches in untangling the complex interplay of extreme events with households’ everyday vulnerabilities and agricultural land-use practices, we make a case for more contextually grounded disaster risk and climate adaptation research.
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| 5. |
- Kmoch, Laura, 1987, et al.
(författare)
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Upland Livelihoods between Local Land and Global Labour Market Dependencies: Evidence from Northern Chin State, Myanmar
- 2018
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- Livelihoods and agrarian change processes across upland South-East Asia have been explored for decades. Yet, knowledge gaps remain about contemporary livelihood strategies and land dependence in areas previously inaccessible to academic research, such as in upland Myanmar. Moreover, new strands of inquiry arise with continued globalisation, e.g., into the effects of remittances and labour migration on household incomes and livelihoods in distant upland areas. This study applied clustering techniques to income accounts of 94 households from northern Chin State, Myanmar to: (i) Identify households’ livelihood strategies; (ii) assess their dependence on access to land and natural resources; and (iii) compare absolute and relative incomes across strategies. We show that households engaged in six relatively distinct livelihood strategies: Relying primarily on own farming activities; making a living off the land with mixed income from agriculture and forest resources; engaging in wage employment; living from remittances; practicing non-forest tree husbandry; or engaging in self-employed business activities. We found significant income inequalities across clusters, with households engaging in remittance and wage-oriented livelihood strategies realizing higher incomes than those primarily involved in land-based activities. Our findings point to differentiated vulnerabilities associated with the identified livelihood strategies—to climate risks, shifting land-governance regimes and labour market forces.
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| 6. |
- Lis, D. C., et al.
(författare)
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Herschel/HIFI measurements of the ortho/para ratio in water towards Sagittarius B2(M) and W31C
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1, s. Article Number: L26 -
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Tidskriftsartikel (refereegranskat)abstract
- We present Herschel/HIFI observations of the fundamental rotational transitions of ortho- and para-H216O and H218O in absorption towards Sagittarius B2(M) and W31C. The ortho/para ratio in water in the foreground clouds on the line of sight towards these bright continuum sources is generally consistent with the statistical high-temperature ratio of 3, within the observational uncertainties. However, somewhat unexpectedly, we derive a low ortho/para ratio of 2.35 +/- 0.35, corresponding to a spin temperature of similar to 27 K, towards Sagittarius B2(M) at velocities of the expanding molecular ring. Water molecules in this region appear to have formed with, or relaxed to, an ortho/para ratio close to the value corresponding to the local temperature of the gas and dust.
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| 7. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten : 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
- 2022
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Ingår i: Aftonbladet. - : Aftonbladet. ; :2022-12-07
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Vi, 1 620 forskare samt lärare vid universitet och högskolor, är eniga med de unga bakom Auroramålet: De drabbas och riskerar att drabbas allvarligt av klimatkrisen under sin livstid. De klimatåtgärder vi vidtar i närtid avgör deras framtid. Sverige måste ta ansvar och göra sin rättvisa andel av det globala klimatarbetet. I strid med Parisavtalet ökar utsläppen av växthusgaser i en takt som gör att 1,5-gradersmålet kan överskridas om några år. De globala effekterna blir allt mer synliga med ständiga temperaturrekord, smältande isar, havshöjning och extremväder som torka, förödande bränder och skyfall med enorma översvämningar, som i Pakistan nyligen. Försörjningen av befolkningen utsätts för allvarliga hot i många länder.Minskningen av den biologiska mångfalden är extrem. Klimatkrisen är enligt WHO det största hotet mot människors hälsa i hela världen och barn utgör en särskilt sårbar grupp. Med Sveriges nordliga läge sker uppvärmningen här dubbelt så fort som det globala genomsnittet. Det förskjuter utbredningsområden för växtlighet och sjukdomsbärande insekter och ökar förekomsten av extremväder såsom värmeböljor, skogsbränder och översvämningar samt av många olika sorters infektioner och allergier. När extremväder ökar, ökar även stressen och risken för mental ohälsa. Värmeböljor ökar risken för sjukdom och död hos sårbara grupper som äldre, små barn och personer med kroniska sjukdomar. De negativa effekterna på hälsan kommer att öka i takt med klimatkrisen och barn riskerar att drabbas av ackumulerade negativa hälsoeffekter under hela sina liv. Redan i dag är mer än hälften av unga mellan 12 och 18 år i Sverige ganska eller mycket oroliga för klimat och miljö. Detta är förståeligt när våra beslutsfattare inte gör vad som krävs.Den juridiska och moraliska grunden för arbetet mot klimatförändringarna är att varje land måste göra sin rättvisa andel av det globala klimatarbetet. Centralt i det internationella klimatramverket är att rika länder med höga historiska utsläpp, däribland Sverige, måste gå före resten av världen. Dessa länder måste också bidra till att finansiera klimatomställningen i länderna i det Globala Syd, som är minst ansvariga för klimatkrisen men drabbas hårdast. Denna rättviseprincip är tydlig i Parisavtalet och var en het diskussionsfråga under COP27 i Sharm el-Sheikh, men lyser med sin frånvaro i det svenska klimatarbetet. Sverige har satt mål för att minska sina utsläpp. Men de är helt otillräckliga: minskningstakten är för låg och målen tillåter samtidigt att åtgärder skjuts på framtiden. Dessutom exkluderas merparten av Sveriges utsläpp från de svenska nationella utsläppsmålen; bland annat utelämnas utsläpp som svensk konsumtion orsakar utanför Sveriges gränser, utsläpp från utrikes transporter och utsläpp från markanvändning och skogsbruk, exempelvis utsläpp från förbränning av biobränslen eller utsläpp från dikade våtmarker (Prop. 2016/17:146 s.25-28).Sverige saknar dessutom ett eget mål för att öka upptaget av växthusgaser genom utökat skydd och restaurering av ekosystem, något som krävs för att begränsa de värsta konsekvenserna av klimatkrisen (IPCC s.32). Trots dessa låga ambitioner misslyckas Sverige med att nå sina utsläppsmål, konstaterar både Klimatpolitiska rådet och Naturvårdsverket. En klimatpolitik i linje med Parisavtalet kräver både att alla typer av växthusgasutsläpp minskar samtidigt som – inte i stället för – upptaget av växthusgaser maximeras: i dag misslyckas Sverige på bägge fronter.Slutsatsen är tydlig. Sverige vidtar inte de åtgärder som krävs för att skydda barns och ungdomars rättigheter enligt Europakonventionen till skydd för de mänskliga rättigheterna. Detta medför allvarliga risker för liv och hälsa för unga generationer, människor i andra länder och särskilt utsatta grupper. Detta kan inte fortsätta. Därför ställer vi oss bakom Auroras krav att Sverige börjar göra sin rättvisa andel och omedelbart sätter igång ett omfattande och långtgående klimatarbete som vilar på vetenskaplig grund och sätter rättvisa i centrum.
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| 8. |
- Svensson, Martin, 1979-, et al.
(författare)
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Pinetree: A Learning Content Repository Based on Semantic Web Technologies
- 2009
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Ingår i: Ninth IEEE International Conference on Advanced Learning Technologies. - : IEEE Press. - 9780769537115 ; , s. 522-526
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Konferensbidrag (refereegranskat)abstract
- During the last few years, mobile devices such as cellular phones and PDAs have become sophisticated tools for creating digital content. Moreover, their built-in or attachable sensor capabilities make it possible to derive metadata that denote the context of the user. The challenge of annotating digital content with contextual metadata is a central part of our current research efforts and the main rationale for the development of Pinetree. Pinetree is a learning content repository based on Semantic Web technologies. The aim of the article is to explore the utility of using RDF (Resource Description Framework) as a data model in a learning content repository. We describe the different components of Pinetree and illustrate its use in a specific learning scenario. Our initial results indicate that a learning content repository based on RDF can be a flexible solution for digital content storage in terms of metadata expressivity, interoperability and data distribution.
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| 9. |
- Andersson, Per A., et al.
(författare)
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Anger and disgust shape judgments of social sanctions across cultures, especially in high individual autonomy societies
- 2024
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- When someone violates a social norm, others may think that some sanction would be appropriate. We examine how the experience of emotions like anger and disgust relate to the judged appropriateness of sanctions, in a pre-registered analysis of data from a large-scale study in 56 societies. Across the world, we find that individuals who experience anger and disgust over a norm violation are more likely to endorse confrontation, ostracism and, to a smaller extent, gossip. Moreover, we find that the experience of anger is consistently the strongest predictor of judgments of confrontation, compared to other emotions. Although the link between state-based emotions and judgments may seem universal, its strength varies across countries. Aligned with theoretical predictions, this link is stronger in societies, and among individuals, that place higher value on individual autonomy. Thus, autonomy values may increase the role that emotions play in guiding judgments of social sanctions.
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| 10. |
- Asavei, T., et al.
(författare)
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Engineering Optically Driven Micromachines. - art. no. 703816
- 2008
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Ingår i: Optical Trapping and Optical Micromanipulation V. - 9780819472588 ; 7038, s. 3816-3816
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Konferensbidrag (refereegranskat)abstract
- Optical forces and torques acting on microscopic objects trapped in focussed laser beams promise flexible methods of driving micromachines through a microscope cover slip or even a cell wall. We are endeavouring to engineer special purpose micro-objects for a range of tasks. Colloidal self assembly of calcium carbonate provides birefringent spheres which can exert considerable torque, while two photon polymerisation allows us to fabricate objects of arbitrary shape that can be designed to exchange both spin and orbital angular momentum. Numerical calculations of forces and torques can allow an optimal design, and optical measurements provide us with certain knowledge of the forces and torques which are actually exerted.
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| 11. |
- Bendz, Anna, 1967, et al.
(författare)
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Why do people accept or reject climate policies targeting food consumption? Unpacking justifications in the public debate in online social forums
- 2023
-
Ingår i: Food Policy. - 0306-9192. ; 121
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Tidskriftsartikel (refereegranskat)abstract
- A shift in dietary habits will be required to meet global climate targets. However, from a social dilemma perspective, major voluntary shifts in diet patterns are unlikely. Hence, government interventions are called for. This may be a perilous political endeavor, since food habits and choices are assumed to be personal and contentious matters and any food regulation policy risks stepping over the line for what people accept, risking policy legitimacy. In order to construct feasible policy measures, it is therefore important to gain knowledge of the prerequisites for support of climate food regulations and to understand why people accept or oppose regulations. The aim of this paper is to do so by analyzing the public debate concerning meat-free days in school canteens and a tax on meat in two public online social forums in Sweden. We seek to 1) map the arguments supporting (non)acceptability of the two food consumption regulation issues and 2) analyze what policy-specific and factual beliefs are reflected in the arguments and then detangle their meaning and content as revealed in the arguments. We find that policy-specific beliefs around freedom, fairness, and effectiveness are commonly used in support of or objection to these policies, but to different degrees, and often linked to factual beliefs about consequences for health or disadvantaged social groups. We conclude that the general reluctance of policy makers to interfere with what people eat is not necessarily well founded, and that better policy design, framing, and communication have the potential to increase policy support.
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| 12. |
- Coria, Jessica, 1979, et al.
(författare)
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The progress of GHG markets : opportunities and risks
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The climate negotiations at the COP15 in December 2009 did not produce a new international treaty with binding emissions commitments but the Copenhagen Accord for dealing with post-2012 climate change. Given the current climate negotiation process it is unlikely that we will see a global climate agreement soon on a global cap between all Convention members participating in a single carbon market. We may be more likely to see a stepwise process moving towards this scenario, most likely involving linkages between different national policy programs when it comes to mitigation as well as offsetting emissions. In such a process countries will offer commitments based on their domestic abilities, preferences and policies, norms and institutions. National and sub-national policies are thus likely to be the de-facto building blocks of nations' abilities to make and fulfill international commitments. However, also with multilateral mitigation programs without binding commitments, carbon markets will be needed as well as international authorities that support measurement, reporting and verification rules and the international registries. Such markets will necessarily be complicated and temporary in a world without an overarching binding agreement. There will be numerous tradeoffs between different kinds of second-best arrangements. The purpose of this report is to build knowledge about the effects of the development of regional and international carbon markets and the auxiliary technology agreements that might be needed. Among the topics we address are: the evolution and integration of carbon markets, the impacts of policy and technology cost uncertainty on the cost of meeting targets through a carbon market mechanism, the effect of banking, price floors and ceilings, institutional constraints and technological change in the further development of carbon markets and their links to other environmental policy instruments, and the potential of REDD-plus to encourage sustainable forest development and climate mitigation.
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| 13. |
- Dalin, Martin, 1982, et al.
(författare)
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Multi-dimensional genomic analysis of myoepithelial carcinoma identifies prevalent oncogenic gene fusions
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Myoepithelial carcinoma (MECA) is an aggressive salivary gland cancer with largely unknown genetic features. Here we comprehensively analyze molecular alterations in 40 MECAs using integrated genomic analyses. We identify a low mutational load, and high prevalence (70%) of oncogenic gene fusions. Most fusions involve the PLAG1 oncogene, which is associated with PLAG1 overexpression. We find FGFR1-PLAG1 in seven (18%) cases, and the novel TGFBR3-PLAG1 fusion in six (15%) cases. TGFBR3-PLAG1 promotes a tumorigenic phenotype in vitro, and is absent in 723 other salivary gland tumors. Other novel PLAG1 fusions include ND4-PLAG1; a fusion between mitochondrial and nuclear DNA. We also identify higher number of copy number alterations as a risk factor for recurrence, independent of tumor stage at diagnosis. Our findings indicate that MECA is a fusion-driven disease, nominate TGFBR3-PLAG1 as a hallmark of MECA, and provide a framework for future diagnostic and therapeutic research in this lethal cancer.
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| 14. |
- Ekström, David, et al.
(författare)
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Optimization of the Internal Structure and Shape of a 470 Dinghy Centerboard
- 2020
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Ingår i: Proceedings (MDPI). - Basel Switzerland : MDPI. - 2504-3900. ; 49:1
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Konferensbidrag (refereegranskat)abstract
- The purpose of this paper is to design an improved centerboard for the Olympic 470 sailing dinghy sailing upwind. The design is improved by introducing a composite design that makes the centerboard twist to windward when sailing upwind, thereby reducing the angle of attack of the hull. The results show that a beneficial twist up to 1.5° is possible to achieve without compromising the centerboard strength. According to our estimates, by utilizing the improved design it is possible to obtain a gain of up to 9 s per race in a world cup race.
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| 15. |
- Engström, David, 1976, et al.
(författare)
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Calibration of spatial light modulators suffering from spatially varying phase response
- 2013
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 21:13, s. 16086-16103
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Tidskriftsartikel (refereegranskat)abstract
- We present a method for converting the desired phase values of a hologram to the correct pixel addressing values of a spatial light modulator (SLM), taking into account detailed spatial variations in the phase response of the SLM. In addition to thickness variations in the liquid crystal layerof the SLM, we also show that these variations in phase response can be caused by a non-uniform electric drive scheme in the SLM or by local heating caused by the incident laser beam. We demonstrate that the use of a global look-up table (LUT), even in combination with a spatially varyingscale factor, generally does not yield sufficiently accurate conversion forapplications requiring highly controllable output fields, such as holographicoptical trapping (HOT). We therefore propose a method where the pixeladdressing values are given by a three-dimensional polynomial, with twoof the variables being the (x;y)-positions of the pixels, and the third theirdesired phase values. The coefficients of the polynomial are determined bymeasuring the phase response in 8×8 sub-sections of the SLM surface; thedegree of the polynomial is optimized so that the polynomial expressionnearly replicates the measurement in the measurement points, while stillshowing a good interpolation behavior in between. The polynomial evaluationincreases the total computation time for hologram generation by onlya few percent. Compared to conventional phase conversion methods, for an SLM with varying phase response, we found that the proposed methodincreases the control of the trap intensities in HOT, and efficiently preventsthe appearance of strong unwanted 0th order diffraction that commonlyoccurs in SLM systems.
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| 16. |
- Engström, David, 1976, et al.
(författare)
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Three-dimensional imaging of liquid crystal structures and defects by means of holographic manipulation of colloidal nanowires with faceted sidewalls
- 2011
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Ingår i: Soft Matter. ; 7, s. 6304-6312
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Tidskriftsartikel (refereegranskat)abstract
- We use nanowires with faceted sidewalls for mapping of the patterns of three-dimensional orientational order and defect structures. In chiral nematics, the nanowires follow the local average orientation of rod-shaped molecules. When spatially translated by use of holographic optical tweezers in three dimensions, they mediate direct nondestructive visualization of the helicoidal ground-state structures, edge and screw dislocations, and kinks, as well as enable non-contact manipulation of these defects. We probe interactions of faceted nanowires with different defects and demonstrate their spontaneous self-alignment along the cores of singular defect lines.
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| 17. |
- Engström, David, 1976, et al.
(författare)
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Unconventional structure-assisted optical manipulation of high-index nanowires in liquid crystals
- 2012
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Ingår i: Optics Express. - 1094-4087. ; 20:7, s. 7741-7748
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Tidskriftsartikel (refereegranskat)abstract
- Stable optical trapping and manipulation of high-index particles in low-index host media is often impossible due to the dominance of scattering forces over gradient forces. Here we explore optical manipulation in liquid crystalline structured hosts and show that robust optical manipulation of high-index particles, such as GaN nanowires, is enabled by laser-induced distortions in long-range molecular alignment, via coupling of translational and rotational motions due to helicoidal molecular arrangement, or due to elastic repulsive interactions with confining substrates. Anisotropy of the viscoelastic liquid crystal medium and particle shape give rise to a number of robust unconventional trapping capabilities, which we use to characterize defect structures and study rheological properties of various thermotropic liquid crystals.
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| 18. |
- Falgarone, E., et al.
(författare)
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CH+(1-0) and 13CH+(1-0) absorption lines in the direction of massive star-forming regions
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1
-
Tidskriftsartikel (refereegranskat)abstract
- We report the detection of the ground-state rotational transition of the methylidyne cation CH+ and its isotopologue (CH+)-C-13 toward the remote massive star-forming regions W33A, W49N, and W51 with the HIFI instrument onboard the Herschel satellite. Both lines are seen only in absorption against the dust continuum emission of the star-forming regions. The CH+ absorption is saturated over almost the entire velocity ranges sampled by the lines-of-sight that include gas associated with the star-forming regions (SFR) and Galactic foreground material. The CH+ column densities are inferred from the optically thin components. A lower limit of the isotopic ratio [(CH+)-C-12]/[(CH+)-C-13]> 35.5 is derived from the absorptions of foreground material toward W49N. The column density ratio, N(CH+)/N(HCO+), is found to vary by at least a factor 10, between 4 and > 40, in the Galactic foreground material. Line-of-sight 12CH+ average abundances relative to total hydrogen are estimated. Their average value, N(CH+)/NH > 2.6 x 10(-8), is higher than that observed in the solar neighborhood and confirms the high abundances of CH+ in the Galactic interstellar medium. We compare this result to the predictions of turbulent dissipation regions (TDR) models and find that these high abundances can be reproduced for the inner Galaxy conditions. It is remarkable that the range of predicted N(CH+)/ N(HCO+) ratios, from 1 to similar to 50, is comparable to that observed.
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| 19. |
- Gerin, M., et al.
(författare)
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Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1, s. Article Number: L16-
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Tidskriftsartikel (refereegranskat)abstract
- We report the detection of the ground state N, J = 1, 3/2 -> 1, 1/2 doublet of the methylidyne radical CH at similar to 532 GHz and similar to 536 GHz with the Herschel/ HIFI instrument along the sight-line to the massive star-forming regions G10.6-0.4 (W31C), W49N, and W51. While the molecular cores associated with these massive star-forming regions show emission lines, clouds in the diffuse interstellar medium are detected in absorption against the strong submillimeter background. The combination of hyperfine structure with emission and absorption results in complex profiles, with overlap of the different hyperfine components. The opacities of most of the CH absorption features are linearly correlated with those of CCH, CN, and HCO+ in the same velocity intervals. In specific narrow velocity intervals, the opacities of CN and HCO+ deviate from the mean trends, giving rise to more opaque absorption features. We propose that CCH can be used as another tracer of the molecular gas in the absence of better tracers, with [CCH]/[H2] similar to 3.2 +/- 1.1 x 10-8. The observed [CN]/[CH], [CCH]/[CH] abundance ratios suggest that the bulk of the diffuse matter along the lines of sight has gas densities nH = n(H) + 2n(H2) ranging between 100 and 1000 cm-3).
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| 20. |
- Gerin, M., et al.
(författare)
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Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6-0.4
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:4, s. 110-
-
Tidskriftsartikel (refereegranskat)abstract
- We report the detection of absorption lines by the reactive ions OH+, H2O+ and H3O+ along the line of sight to the submillimeter continuum source G10.6$-$0.4 (W31C). We used the Herschel HIFI instrument in dual beam switch mode to observe the ground state rotational transitions of OH+ at 971 GHz, H2O+ at 1115 and 607 GHz, and H3O+ at 984 GHz. The resultant spectra show deep absorption over a broad velocity range that originates in the interstellar matter along the line of sight to G10.6$-$0.4 as well as in the molecular gas directly associated with that source. The OH+ spectrum reaches saturation over most velocities corresponding to the foreground gas, while the opacity of the H2O+ lines remains lower than 1 in the same velocity range, and the H3O+ line shows only weak absorption. For LSR velocities between 7 and 50 kms$^{-1}$ we estimate total column densities of $N$(OH+) $> 2.5 \times 10^{14}$ cm$^{-2}$, $N$(H2O+) $\sim 6 \times 10^{13}$ cm$^{-2}$ and $N$(H3O+) $\sim 4.0 \times 10^{13}$ cm$^{-2}$. These detections confirm the role of O$^+$ and OH$^+$ in initiating the oxygen chemistry in diffuse molecular gas and strengthen our understanding of the gas phase production of water. The high ratio of the OH+ by the H2O+ column density implies that these species predominantly trace low-density gas with a small fraction of hydrogen in molecular form.
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| 21. |
- Holte, Martin Bech, 1979-
(författare)
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Essays on Incentives and Leadership
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- "Taxation, Career Concerns and CEO Pay". This paper proposes a simple dynamic model of equilibrium CEO compensation. Motivated by the strengthened career incentives stemming from the fall in the top income tax rates over the past decades, I study the implications of a model where the quality of talent identification depends on how hard individuals work in order to be among the winners in the contest for managerial positions. It is shown how the compensation of CEOs can be interpreted in this light, across time, across industries, and across countries, and I provide some evidence showing that the predictions of the model are in line with several empirical developments over the past decades."Incentives under Communism: The Value of Low-Quality Goods". In this paper, I study how efficiently centrally planned regimes can provide incentives across different stages of economic development. In particular, I study the attractiveness of an incentive system based on exclusive provision of high-quality goods to high-ranked members of society. At low levels of economic development, a self-interested regime can exploit such an incentive system to reduce the cost of providing incentives. However, such an incentive system generally loses its attractiveness as the economy grows. The economic performance of the centrally planned economies is then analyzed in light of this result."The Business of Troubled Autocrats". Many autocrats control resource rents. Typically, they rely on these rents in order to buy political support. In this paper, I study how such autocrats behave in product and capital markets, in particular at times of financial distress. The main questions are: How does the asset position of an autocrat affect his behavior as a producer in a market with rents? From whom does the autocrat obtain financing in order to get out of difficulties? I show that when the asset position of the autocrat drops below a certain threshold, output drops below the level of a standard monopolist. Further, the autocrat can obtain less expensive financing domestically by exploiting the presence of vested interests, implying that there is zero foreign debt in equilibrium.
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| 22. |
- Mookerjea, B., et al.
(författare)
-
Excitation and abundance of C3 in star forming cores Herschel/HIFI observations of the sight-lines to W31C and W49N
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1, s. Article Number: L13 -
-
Tidskriftsartikel (refereegranskat)abstract
- We present spectrally resolved observations of triatomic carbon (C-3) in several ro-vibrational transitions between the vibrational ground state and the low-energy nu(2) bending mode at frequencies between 1654-1897 GHz along the sight-lines to the submillimeter continuum sources W31C and W49N, using Herschel's HIFI instrument. We detect C-3 in absorption arising from the warm envelope surrounding the hot core, as indicated by the velocity peak position and shape of the line profile. The sensitivity does not allow to detect C-3 absorption due to diffuse foreground clouds. From the column densities of the rotational levels in the vibrational ground state probed by the absorption we derive a rotation temperature (T-rot) of similar to 50-70 K, which is a good measure of the kinetic temperature of the absorbing gas, as radiative transitions within the vibrational ground state are forbidden. It is also in good agreement with the dust temperatures for W31C and W49N. Applying the partition function correction based on the derived T-rot, we get column densities N(C-3) similar to 7-9 x 10(14) cm(-2) and abundance x(C-3) similar to 10(-8) with respect to H-2. For W31C, using a radiative transfer model including far-infrared pumping by the dust continuum and a temperature gradient within the source along the line of sight we find that a model with x(C-3) = 10(-8), T-kin = 30-50 K, N(C-3) = 1.5 x 10(15) cm(-2) fits the observations reasonably well and provides parameters in very good agreement with the simple excitation analysis.
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| 23. |
- Neufeld, D. A., et al.
(författare)
-
Herschel/HIFI observations of interstellar OH+ and H2O+ towards W49N: a probe of diffuse clouds with a small molecular fraction
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1, s. Article Number: L10-
-
Tidskriftsartikel (refereegranskat)abstract
- We report the detection of absorption by interstellar hydroxyl cations and water cations, along the sight-line to the bright continuum source W49N. We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 972 GHz N = 1-0 transition of OH+ and the 1115 GHz 1(11)-0(00) transition of ortho-H2O+. The resultant spectra show absorption by ortho-H2O+, and strong absorption by OH+, in foreground material at velocities in the range 0 to 70 km s(-1) with respect to the local standard of rest. The inferred OH+/H2O+ abundance ratio ranges from similar to 3 to similar to 15, implying that the observed OH+ arises in clouds of small molecular fraction, in the 2-8% range. This conclusion is confirmed by the distribution of OH+ and H2O+ in Doppler velocity space, which is similar to that of atomic hydrogen, as observed by means of 21 cm absorption measurements, and dissimilar from that typical of other molecular tracers. The observed OH+/H abundance ratio of a few x10(-8) suggests a cosmic ray ionization rate for atomic hydrogen of 0.6-2.4 x 10(-16) s(-1), in good agreement with estimates inferred previously for diffuse clouds in the Galactic disk from observations of interstellar H-3(+) and other species.
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| 24. |
- Neufeld, D.A., et al.
(författare)
-
Strong absorption by interstellar hydrogen fluoride: Herschel/HIFI observations of the sight-line to G10.6-0.4 (W31C)
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:4, s. 108-
-
Tidskriftsartikel (refereegranskat)abstract
- We report the detection of strong absorption by interstellar hydrogen fluoride along the sight-line to the submillimeter continuum source G10.6-0.4 (W31C). We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 1232.4763 GHz J=1-0 HF transition in the upper sideband of the Band 5a receiver. The resultant spectrum shows weak HF emission from G10.6-0.4 at LSR velocities in the range -10 to -3 km/s, accompanied by strong absorption by foreground material at LSR velocities in the range 15 to 50 km/s. The spectrum is similar to that of the 1113.3430 GHz 1(11)-0(00) transition of para-water, although at some frequencies the HF (hydrogen fluoride) optical depth clearly exceeds that of para-H2O. The optically-thick HF absorption that we have observed places a conservative lower limit of 1.6E+14 cm-2 on the HF column density along the sight-line to G10.6-0.4. Our lower limit on the HF abundance, 6E-9 relative to hydrogen nuclei, implies that hydrogen fluoride accounts for between ~ 30 and 100% of the fluorine nuclei in the gas phase along this sight-line. This observation corroborates theoretical predictions that - because the unique thermochemistry of fluorine permits the exothermic reaction of F atoms with molecular hydrogen - HF will be the dominant reservoir of interstellar fluorine under a wide range of conditions.
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| 25. |
- Nieminen, T. A., et al.
(författare)
-
Tailoring particles for optical trapping and micromanipulation: An overview
- 2008
-
Ingår i: Piers 2008 Hangzhou: Progress in Electromagnetics Research Symposium, Vols I and Ii, Proceedings. - 9781934142004 ; , s. 864-868
-
Konferensbidrag (refereegranskat)abstract
- Optical trapping and micromanipulation has developed from an interesting novelty to a powerful and widely used tool, with the capability to move or trap microscopic live biological specimens and measure forces on the order of piconewtons, typical of forces in microbiological systems. Despite this, the range of particles typically trapped or manipulated is quite small, and it is unusual to see applications involving objects other than biological specimens or homogeneous isotropic microspheres, typically polymer or silica. However, particles can be modified or specially fabricated to expand the possible applications of optical tweezers. For example, while non-absorbing homogeneous isotropic spheres cannot be rotated, optically anisotropic spheres can, and can therefore function as microscopic torque sensors, extending the usual translational micromanipulation and force measurement to rotational manipulation and torque sensing. The development of such particles has led to applications in microscale metrology and biophysics, along with potential deployment of optically-driven micro-machines in lab-on-a-chip devices. We present an overview of our work on the tailoring of microparticles for versatile optical trapping and micromanipulation. This includes approaches based on controlled chemistry - nano-assembly - and optical microfabrication. Beginning with the production of anisotropic vaterite microspheres, we review some. of the applications, and difficulties encountered along the way. Some of these difficulties can be overcome by coating of the vaterite microspheres. We also discuss the use of anti-reflection coating to allow strong trapping of high refractive index particles. The alternative strategy of producing arbitrarily shaped polymer microstructures through two-photon photopolymerization is also discussed. This can be used to produce optically-driven microrotors or structurally anisotropic microspheres to replace vaterites for particular applications.
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| 26. |
- Paganini, Anna, 1979, et al.
(författare)
-
Being Normal yet Different : A Qualitative Study on the Dualistic Experience of Living With Unilateral Cleft Lip and Palate
- 2022
-
Ingår i: The Cleft Palate-Craniofacial Journal. - : SAGE Publications. - 1055-6656 .- 1545-1569. ; , s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of the present study was to describe the experiences of young adults living with cleft lip and palate (CLP) and to explore potential gender differences. Design A descriptive qualitative study was designed involving semi-structured interviews. The interviews were analyzed using qualitative content analysis, as described by Graneheim and Lundman. Participants A total of 9 women and 8 men, aged 22 to 26 years with UCLP. Results The main theme identified was: the duality of living with a cleft—being normal yet different, and 2 subcategories: “My cleft and me” and “My cleft and the World.” The participants described themselves as normal yet different, both in relation to themselves and in relation to others. They also stated that gender norms regarding appearance affected their lives and how they saw the cleft. Conclusion This study adds to the growing body of qualitative research on CLP. It highlights the dualistic experiences of feeling normal and different at the sametime. The interviews indicated that this dualism was based on context and gender, showing the psychological complexity of an individual. The clinical implications of this study emphasizes the need of a person-centered care approach in the cleft care setting where the clinicians are aware of the potential dualistic experience that also may differ over time that individuals with cleft can experience. This can also help clinicians better understand and help patients reduce distress and strengthen positive coping mechanisms.
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| 27. |
- Pannee, Josef, 1979, et al.
(författare)
-
The amyloid-beta degradation pattern in plasma A possible tool for clinical trials in Alzheimer's disease
- 2014
-
Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 573, s. 7-12
-
Tidskriftsartikel (refereegranskat)abstract
- Amyloid beta (A beta) is the main component of plaques, the central neuropathological hallmark in Alzheimer's disease (AD). A beta is derived from the amyloid precursor protein (APP) by beta- and gamma-secretase-mediated cleavages. A large number of A beta peptides are found in cerebrospinal fluid and these peptides are produced in specific metabolic pathways, which are important for diagnosis, in drug development and to explore disease pathogenesis. To investigate whether a similar pattern could be found also in blood samples, an immunoprecipitation (IP) based method for enrichment of A beta peptides from human plasma was developed. The peptides were analyzed using matrix-assisted-laser-desorption/ionization time-of-flight/time-of-flight mass spectrometry for A beta profiling and selected reaction monitoring (SRM) for MS quantification of A beta 1-38, A beta 1-40 and A beta 1-42 using tripe quadrupole MS. Sixteen N- or C-terminally truncated A beta peptides were reproducibly detected in human plasma, of which 11 were verified by tandem MS. In a pilot study including 9 AD patients and 10 controls, where A beta 1-38, A beta 1-40 and A beta 1-42 were quantified using SRM, no AD-associated change in plasma levels of the peptides were observed. Using MS-based measurement techniques, we show that several A beta peptides can be monitored in a single analysis and the developed methods have the potential to be used as a read out in clinical trials of drugs affecting APP processing or A beta homeostasis.
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| 28. |
- Parkin, S. J., et al.
(författare)
-
Highly birefringent vaterite microspheres: production, characterization and applications for optical micromanipulation
- 2009
-
Ingår i: Optics Express. - 1094-4087. ; 17:24, s. 21944-21955
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports on a simple synthesis and characterization of highly birefringent vaterite microspheres, which are composed of 20-30 nm sized nanocrystalls. Scanning electron microscopy shows a quite disordered assembly of nanocrystals within the microspheres. However, using optical tweezers, the effective birefringence of the microspheres was measured to Delta n = 0.06, which compares to Delta n = 0.1 of vaterite single crystals. This suggests a very high orientation of the nanocrystals within the microspheres. A hyperbolic model of the direction of the optical axis throughout the vaterite spherulite best fits the experimental data. Results from polarized light microscopy further confirm the hyperbolic model. (C) 2009 Optical Society of America
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| 29. |
-
Perspektiv på offentlig verksamhet i utveckling : tolv kapitel om demokrati, styrning och effektivitet
- 2011. - 1
-
Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Perspektiv på offentlig verksamhet i utveckling - Tolv kapitel om demokrati, styrning och effektivitet samlar texter från doktorander och forskare knutna till Forskarskolan Offentlig verksamhet i utveckling (FOVU) vid Örebro Universitet. Antologin erbjuder en mångdisciplinär och omfångsrik behandling av en rad viktiga utmaningar för dagens offentlig verksamhet. I boken behandlas ämnen som korruption, jämställdhet, trygghet, medborgardialog, sjukskrivning och högerextremism. Målsättningen med boken är att skapa en bro mellan inomvetenskapliga debatter, offentlig praktik och politik. Här erbjuds kortare texter som på ett överskådligt sätt angriper praktikrelevanta ämnen utan att göra avkall på den vetenskapliga kvaliteten. Vissa texter erbjuder forskningsöversikter och reder ut oklarheter i teoretiska debatter, medan andra presenterar resultat av empirisk forskning.
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| 30. |
- Persson, Carina, 1964, et al.
(författare)
-
Nitrogen hydrides in interstellar gas Herschel/HIFI observations towards G10.6-0.4 (W31C)
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1, s. Article Number: L45 -
-
Tidskriftsartikel (refereegranskat)abstract
- The HIFI instrument on board the Herschel Space Observatory has been used to observe interstellar nitrogen hydrides along the sight-line towards G10.6-0.4 in order to improve our understanding of the interstellar chemistry of nitrogen. We report observations of absorption in NH N = 1
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| 31. |
- Persson, Martin, 1979
(författare)
-
Advances in Holographic Optical Trapping
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Holographic optical trapping (HOT) is a technique for non-invasive dynamic anipulation of multiple microscopic objects, which has been used for many applications in the life sciences during the past decade. The technique uses holographic beam steering with a spatial light modulator (SLM) to direct light to the desired positions of optical traps. In many cases, the control of the optical intensity of the traps is impaired by imperfections in the SLM. This has limited the use of HOT for applications sensitive to variations in the trap intensities, such as optical force measurement (OFM). Also, the algorithms for optimization of holograms used in HOT are computationally demanding, and real-time manipulation with optimized holograms has not been possible. In this thesis, four different methods for improving the accuracy of holographic beam steering are presented, along with a novel application for the combination of HOT and position measurement. The control of trap intensities is improved by compensating for crosstalk between pixels, and for spatial variations of the phase response of the SLM; and by dumping a controlled amount of light to specified regions away from the traps. Variations in trap intensities occurring when updating the SLM with new holograms are suppressed by enforcing a stronger correlation between consecutive holograms. The methods consist of modifications of the algorithm used for hologram generation, or alternative methods for post-processing of generated holograms. Applications with high stability requirements, such as OFM with HOT, will benefit from the presented improvements. A method for reducing computation time for hologram optimization is also presented, allowing the accuracy improvements to be used also for time critical applications. Further, it is shown that position measurement of nanowires, held by multiple optical traps, can be used to probe the orientational structure and defects in liquid crystal materials.
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| 32. |
- Persson, Martin, 1979, et al.
(författare)
-
Computer Generated Holograms Designed to Reduce Intensity Fluctuations During SLM Update
- 2009
-
Ingår i: Digital Holography and Three-Dimensional Imaging, OSA Technical Digest (CD). - Washington, D.C. : OSA. - 2162-2701. ; , s. DWC3-
-
Konferensbidrag (refereegranskat)abstract
- We have investigated design criteria for calculation of computer generated holograms, aiming to reduce the deterioration of the spot pattern during SLM updates. A modified Gerchberg-Saxton algorithm that efficiently minimizes unwanted intensity fluctuations is introduced.
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| 33. |
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| 34. |
- Persson, Martin, 1979, et al.
(författare)
-
Improving spot uniformity in holographic optical tweezers
- 2011
-
Ingår i: Optics InfoBase Conference Papers. - Washington, D.C. : OSA. - 2162-2701. - 9781557529091
-
Konferensbidrag (refereegranskat)abstract
- We have developed a method for compensating for crosstalk between adjacent pixels in liquid crystal based spatial light modulators. The method decreases the uniformity error of the trap intensities in holographic optical tweezers (HOT) systems.
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| 35. |
- Persson, Martin, 1979, et al.
(författare)
-
Minimizing intensity fluctuations in dynamic holographic optical tweezers by restricted phase change
- 2010
-
Ingår i: Optics Express. - 1094-4087. ; 18:11, s. 11250-11263
-
Tidskriftsartikel (refereegranskat)abstract
- We present a method for reducing intensity fluctuations that typically occur when a spatial light modulator is updated between consecutive computer generated holograms. The method is applicable to most iterative hologram generating algorithms and minimizes the average phase difference between consecutive holograms. Applications with high stability requirements, such as optical force measurement with holographic optical tweezers, should benefit from this improvement. (C) 2010 Optical Society of America
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| 36. |
- Persson, Martin, 1979, et al.
(författare)
-
Probing the elasticity of single yeast cells with holographic optical tweezers.
- 2013
-
Ingår i: Optics in the Life Sciences Congress Technical Digest. - 9781557529664
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The elasticity of single yeast cells is probed using optical force measurement in a holographic optical tweezers setup. The measurements reveal differences in cell wall /membrane stability due to the absence of various proteins.
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| 37. |
- Persson, Martin, 1979, et al.
(författare)
-
Real-time generation of fully optimized holograms for optical trapping applications
- 2011
-
Ingår i: Proc. SPIE. - : SPIE. ; 8097
-
Konferensbidrag (refereegranskat)abstract
- We have implemented several algorithms for hologram generation, aimed for holographic optical tweezers applications, using the parallel computing architecture CUDA. We compare required computation time for different implementations of the Gerchberg-Saxton algorithm and provide guidelines for choosing the best suited version with respect to the application. We also show that additional calculations, compensating for limitations in the used spatial light modulator and optical system, can be included in the hologram generating software with little or no loss in computational speed.
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| 38. |
- Persson, Martin, 1979, et al.
(författare)
-
Reducing the effect of pixel crosstalk in phase only spatial light modulators
- 2012
-
Ingår i: Optics Express. - 1094-4087. ; 20:20, s. 22334-22343
-
Tidskriftsartikel (refereegranskat)abstract
- A method for compensating for pixel crosstalk in liquid crystal based spatial light modulators is presented. By modifying a commonly used hologram generating algorithm to account for pixel crosstalk, the intensity errors in obtained diffraction spot intensities are significantly reduced. We also introduce a novel method for characterizing the pixel crosstalk in phase-only spatial light modulators, providing input for the hologram generating algorithm. The methods are experimentally evaluated and an improvement of the spot uniformity by more than 100% is demonstrated for an SLM with large pixel crosstalk.
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| 39. |
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| 40. |
- Roelofs, S. H., et al.
(författare)
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Calibration of trap stiffness and viscoelasticity in polymer solutions - art. no. 703823
- 2008
-
Ingår i: Optical Trapping and Optical Micromanipulation V. - : SPIE. - 9780819472588 ; 7038, s. 3823-3823
-
Konferensbidrag (refereegranskat)abstract
- We present an experimental demonstration of a method using optical tweezers proposed by Fischer and Berg-Sorensen for measuring viscoelasticity using optical tweezers. it is based on a sinusoidal oscillation of the liquid in combination with force measurements using optical tweezers. We verify the method by applying it to measurements in water, glycerol and polyethylene oxide (PEO).
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| 41. |
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| 42. |
- Sonnentrucker, P., et al.
(författare)
-
Detection of hydrogen fluoride absorption in diffuse molecular clouds with Herschel/HIFI: an ubiquitous tracer of molecular gas
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1, s. Article Number: L12-
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the detection of absorption by interstellar hydrogen fluoride (HF) along the sight line to the submillimeter continuum sources W49N and W51. We have used Herschel's HIFI instrument in dual beam switch mode to observe the 1232.4762 GHz J = 1-0 HF transition in the upper sideband of the band 5a receiver. We detected foreground absorption by HF toward both sources over a wide range of velocities. Optically thin absorption components were detected on both sight lines, allowing us to measure - as opposed to obtain a lower limit on - the column density of HF for the first time. As in previous observations of HF toward the source G10.6-0.4, the derived HF column density is typically comparable to that of water vapor, even though the elemental abundance of oxygen is greater than that of fluorine by four orders of magnitude. We used the rather uncertain N(CH) - N(H-2) relationship derived previously toward diffuse molecular clouds to infer the molecular hydrogen column density in the clouds exhibiting HF absorption. Within the uncertainties, we find that the abundance of HF with respect to H-2 is consistent with the theoretical prediction that HF is the main reservoir of gas-phase fluorine for these clouds. Thus, hydrogen fluoride has the potential to become an excellent tracer of molecular hydrogen, and provides a sensitive probe of clouds of small H-2 column density. Indeed, the observations of hydrogen fluoride reported here reveal the presence of a low column density diffuse molecular cloud along the W51 sight line, at an LSR velocity of similar to 24 km s(-1), that had not been identified in molecular absorption line studies prior to the launch of Herschel.
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| 43. |
- Stadler, Michael, et al.
(författare)
-
A Customised Finn Dinghy Rudder for Optimal Olympic Performance
- 2020
-
Ingår i: Proceedings (MDPI). - Basel Switzerland : MDPI. - 2504-3900. ; 49:1
-
Konferensbidrag (refereegranskat)abstract
- Because of the long history of the Finn Dinghy sailing class, the difference between a gold medal and a mediocre result often comes down to personal mistakes of the sailor, or to who has the most optimised equipment. Regarding the latter, the Finn class rules permit certain design variations of the hull, mast, sail and rudder. In the current contribution, we describe a method for developing a customised rudder system aimed at optimal performance during the Tokyo 2020 Olympics. Based on hydrodynamic analysis of existing rudder designs, an improved rudder geometry was developed. Based on the concept geometry, the rudder and tiller were structurally designed and manufactured to achieve high stiffness and sufficient strength, while respecting the minimum mass requirements as specified by the rules.
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| 44. |
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| 45. |
- Staffas, Anna, 1982, et al.
(författare)
-
Wild-type KRAS inhibits oncogenic KRAS-induced T-all in mice.
- 2015
-
Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 29, s. 1032-1040
-
Tidskriftsartikel (refereegranskat)abstract
- The role of hyperactive RAS signaling is well established in myeloid malignancies but less clear in T-cell malignancies. The Kras2LSLMx1-Cre (KM) mouse model expresses endogenous KRASG12D in hematopoietic cells and is widely used to study mechanisms and treatment of myeloproliferative neoplasms (MPN). The model displays an intriguing shift from MPN to acute T-cell leukemia (T-ALL) after transplantation to wild-type mice but the mechanisms underlying this lineage shift is unknown. Here, we show that KRASG12D increases proliferation of both myeloid and T-cell progenitors, but whereas myeloid cells differentiate, T-cell differentiation is inhibited at early stages. Secondary mutations in the expanded pool of T-cell progenitors accompany T-ALL development, and our results indicate that the shift from myeloid to T-lymphoid malignancy after transplantation is explained by the increased likelihood for secondary mutations when the tumor life-span is increased. We demonstrate that tumor life span increases after transplantation because primary KM mice die rapidly, not from MPN, but from KRASG12D expression in nonhematopoietic cells which causes intestinal bleeding and severe anemia. We also identify loss of the wild-type KRAS allele as a secondary mutation in all T-ALL cells and provide evidence that wild-type KRAS acts as a tumor suppressor in the T-cell lineage in mice.Leukemia accepted article preview online, 05 November 2014. doi:10.1038/leu.2014.315.
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| 46. |
- Stenberg, Simon, et al.
(författare)
-
Control of mitochondrial superoxide production includes programmed mtDNA deletion and restoration
- 2020
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Deletion of mitochondrial DNA in eukaryotes is mainly attributed to rare accidental events associated with mitochondrial replication or repair of double-strand breaks. We report the discovery that yeast cells arrest harmful intramitochondrial superoxide production by shutting down respiration through genetically controlled deletion of mitochondrial oxidative phosphorylation genes. We show that the regulatory circuitry underlying this editing critically involves the antioxidant enzyme superoxide dismutase 2 and two-way mitochondrial-nuclear communication. While mitochondrial DNA homeostasis is rapidly restored after cessation of a short-term superoxide stress, long-term stress causes maladaptive persistence of the deletion process, leading to complete annihilation of the cellular pool of intact mitochondrial genomes and irrevocable loss of respiratory ability. Our results may therefore be of etiological as well as therapeutic importance with regard to age-related mitochondrial impairment and disease.One-Sentence SummaryGenetically controlled editing of mitochondrial DNA is an integral part of the yeast’s defenses against oxidative damage.
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| 47. |
- Stenberg, Simon, et al.
(författare)
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Genetically controlled mtDNA deletions prevent ROS damage by arresting oxidative phosphorylation.
- 2022
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Ingår i: eLife. - 2050-084X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Deletion of mitochondrial DNA in eukaryotes is currently attributed to rare accidental events associated with mitochondrial replication or repair of double-strand breaks. We report the discovery that yeast cells arrest harmful intramitochondrial superoxide production by shutting down respiration through genetically controlled deletion of mitochondrial oxidative phosphorylation genes. We show that this process critically involves the antioxidant enzyme superoxide dismutase 2 and two-way mitochondrial-nuclear communication through Rtg2 and Rtg3. While mitochondrial DNA homeostasis is rapidly restored after cessation of a short-term superoxide stress, long-term stress causes maladaptive persistence of the deletion process, leading to complete annihilation of the cellular pool of intact mitochondrial genomes and irrevocable loss of respiratory ability. This shows that oxidative stress-induced mitochondrial impairment may be under strict regulatory control. If the results extend to human cells, the results may prove to be of etiological as well as therapeutic importance with regard to age-related mitochondrial impairment and disease.
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| 48. |
- Vogel, R., et al.
(författare)
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Synthesis and Surface Modification of Birefringent Vaterite Microspheres
- 2009
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Ingår i: Langmuir. - 0743-7463. ; 25:19, s. 11672-11679
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the synthesis of birefringent vaterite microspheres with narrow size distribution using a seeded growth method. In a post-treatment the microspheres were stabilized and functionalized through coating with a combination of organosilica and silica. The coating vastly enhanced the stability of the vaterite microspheres in biological buffers and allowed the attachment of biomolecules such as DNA or proteins. As an example, streptavidin was attached to the surface of the functionalized microspheres. These results pave the way for the use of birefringent vaterite particles for the micromanipulation of single biological molecules such as DNA or specific proteins in an optical trap capable of exerting and measuring torques. The stabilized birefringent microspheres may also find use for biosensor and biological screening applications.
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| 49. |
- Wolfson, D., et al.
(författare)
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Rapid 3D fluorescence imaging of individual optically trapped living immune cells
- 2015
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Ingår i: Journal of Biophotonics. - : Wiley. - 1864-0648 .- 1864-063X. ; 8:3, s. 208-216
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate an approach to rapidly characterize living suspension cells in 4 dimensions while they are immobilized and manipulated within optical traps. A single, high numerical aperture objective lens is used to separate the imaging plane from the trapping plane. This facilitates full control over the position and orientation of multiple trapped cells using a spatial light modulator, including directed motion and object rotation, while also allowing rapid 4D imaging. This system is particularly useful in the handling and investigation of the behavior of non-adherent immune cells. We demonstrate these capabilities by imaging and manipulating living, fluorescently stained Jurkat T cells.
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