| 1. |
- Adolfsson, Jan, et al.
(författare)
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Clinical characteristics and primary treatment of prostate cancer in Sweden between 1996 and 2005
- 2007
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Ingår i: Scandinavian Journal of Urology and Nephrology. - : Informa UK Limited. - 0036-5599 .- 1651-2065. ; 41:6, s. 456-477
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The incidence of prostate cancer is rising rapidly in Sweden and there is a need to better understand the pattern of diagnosis, tumor characteristics and treatment. MATERIAL AND METHODS: Between 1996 and 2005, all new cases of adenocarcinoma of the prostate gland were intended to be registered in the National Prostate Cancer Register (NPCR). This register contains information on diagnosing unit, date of diagnosis, cause of diagnosis, tumor grade, tumor stage according to the TNM classification in force, serum prostate-specific antigen (PSA) levels at diagnosis and primary treatment given within the first 6 months after diagnosis. RESULTS: In total, 72,028 patients were registered, comprising >97% of all pertinent incident cases of prostate cancer in the Swedish Cancer Register (SCR). During the study period there was a considerable decrease in median age at the time of diagnosis, a stage migration towards smaller tumors, a decrease in median serum PSA values at diagnosis, a decrease in the age-standardized incidence rate of men diagnosed with distant metastases or with a PSA level of > 100 ng/ml at diagnosis and an increase in the proportion of tumors with Gleason score <6. Relatively large geographical differences in the median age at diagnosis and the age-standardized incidence of cases with category T1c tumors were observed. Treatment with curative intent increased dramatically and treatment patterns varied according to geographical region. In men with localized tumors and a PSA level of <20 ng/ml at diagnosis, expectant treatment was more commonly used in those aged > or =75 years than in those aged <75 years. Also, the pattern of endocrine treatment varied in different parts of Sweden. CONCLUSIONS: All changes in the register seen over time are consistent with increased diagnostic activity, especially PSA testing, resulting in an increased number of cases with early disease, predominantly tumors in category T1c. The patterns of diagnosis and treatment of prostate cancer vary considerably in different parts of Sweden. The NPCR continues to be an important source for research, epidemiological surveillance of the incidence, diagnosis and treatment of prostate cancer.
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| 2. |
- Davidsson, Kent, 1967, et al.
(författare)
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Potassium, chlorine, and sulfur in ash, particles, deposits, and corrosion during wood combustion in a circulating fluidized-bed boiler
- 2007
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 21:1, s. 71-81
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the addition of chlorine and/or sulfur to the fuel on fly ash composition, deposit formation, and superheater corrosion has been studied during biomass combustion in a circulating fluidized-bed boiler. The chlorine (HCl (aq)) and sulfur (SO2 (g)) were added in proportions of relevance for the potassium chemistry. The composition of the bottom and the fly ashes was analyzed. Gas and particle measurements were performed downstream of the cyclone before the convection pass and the flue gas composition was recorded in the stack with a series of standard instruments and an FTIR analyzer. At the position downstream of the cyclone, a deposit probe was situated, simulating a superheater tube. Deposits on the probe and initial corrosion were examined. It is concluded that addition of sulfur and chlorine increases the formation of submicron particles leading to deposition of potassium sulfate and chloride. The results compare well with earlier work based on laboratory-scale experiments concerning effects of chlorine and sulfur on potassium chemistry.
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| 3. |
- Folkeson, Nicklas, 1981, et al.
(författare)
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Fireside corrosion of stainless and low alloyed steels in a waste-fired CFB boiler; The effect of adding sulphur to the fuel
- 2008
-
Ingår i: Materials Science Forum. ; 595-598, s. 289-297
-
Tidskriftsartikel (refereegranskat)abstract
- Corrosion field tests have been carried out in the superheater region of a commercial waste-fired 75MW CFBC boiler using air cooled probes. Exposure time was 24 and 1000 hours. The effect of adding sulphur to the fuel on the corrosion of two high alloyed steels and a low alloyed steel was studied. The fuel consisted of 50% household waste and 50% industrial waste. The exposed samples were analyzed by ESEM/EDX and XRD. Metal loss was determined after 1000 hours. Both materials suffered significant corrosion in the absence of sulphur addition and the addition of sulphur to the fuel reduced corrosion significantly. The rapid corrosion of the high alloyed steel in the absence of sulphur addition is caused by the destruction of the chromium-containing protective oxide by formation of calcium chromate. Adding sulphur to the fuel inhibited chromate formation and increased the sulphate/chloride ratio in the deposit. Iron(II) chloride formed on the low alloyed steel regardless of whether sulphur was added or not.
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| 4. |
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| 5. |
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| 6. |
- Pettersson, Jesper, 1978, et al.
(författare)
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The influence of sulphur additions on the corrosive environment in a waste-fired CFB boiler
- 2005
-
Ingår i: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 522-523, s. 563-570
-
Tidskriftsartikel (refereegranskat)abstract
- Corrosion/deposition field tests have been carried out in the superheater region of a commercial waste-fired 75MW CFBC boiler using air cooled probes. The influence of material temperature (450-500 degrees C), flue gas temperature, temperature variations (i.e. thermal cycling) and additives to the fuel (elemental sulphur and dolomite) on deposition and corrosion was studied. The results presented here mainly consider the influence of sulphur additions to the fuel. The fuel was a mixture of 50% household waste and 50% industrial waste. After exposure the samples were analyzed by ESEM/EDX, XRD, AAS, FIB and IC. With no additional sulphur, alkali chlorides made up a large part of the deposit/corrosion product layer and in some cases chromate (VI) was detected. It is suggested that the chromate (VI) has formed by reaction of the protective oxide with alkali chlorides in the deposit. Adding sulphur to the fuel changed the composition of the deposits, alkali chlorides being largely replaced by alkali sulphates. No chromates(VI) were detected in the sulphur-added runs. It is suggested that adding sulphur to the fuel may decrease fireside corrosion because it changes the composition of the deposit. Alkali sulphates are much less corrosive than alkali chlorides partly because they do not form chromate(VI).
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| 7. |
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| 8. |
- Belitsky, Victor, 1955, et al.
(författare)
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A new 3 mm band receiver for the Onsala 20 m antenna
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 580
-
Tidskriftsartikel (refereegranskat)abstract
- A new receiver for the Onsala 20 m antenna with the possibility of being equipped with 3 mm and 4 mm bands has been built and the 3 mm channel has been commissioned during the Spring 2014. For single-dish operation, the receiver uses an innovative on-source/off-source optical switch. In combination with additional optical components and within the same optical layout, the switch provides two calibration loads (for the 3 mm and 4 mm channels), sideband rejection measurement, and tuning possibilities. The optical layout of the receiver employs all cold (4 K) offset elliptical mirrors for both channels, whereas the on-off switch employs flat mirrors only. The 3 mm channel employs a sideband separation (2SB) dual polarization receiver with orthomode transducer (OMT), 4-8 GHz intermediate frequency (IF), x? 2pol x? upper and lower sidebands (USB? +? LSB). The cryostat has four optical windows made of high density polyethylene (HDPE) with anti-reflection corrugations, two for the signal and two for each frequency band cold load. The cryostat uses a two-stage cryocooler produced by Sumitomo HI? RDK? 408D2 with anti-vibration suspension of the cold-head to minimize impact of the vibrations on the receiver stability. The local oscillator (LO) system is based on a Gunn oscillator with aphase lock loop (PLL) and four mechanical tuners for broadband operation, providing independently tunable LO power for each polarization. This paper provides a technical description of the receiver and its technology and could be useful for instrumentation engineers and observers using the Onsala 20 m telescope.
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| 9. |
- Bergemalm, Daniel, 1977-, et al.
(författare)
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Systemic Inflammation in Preclinical Ulcerative Colitis
- 2021
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Ingår i: Gastroenterology. - : AGA Institute. - 0016-5085 .- 1528-0012. ; 161:5, s. 1526-1539.e9
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Preclinical ulcerative colitis is poorly defined. We aimed to characterize the preclinical systemic inflammation in ulcerative colitis, using a comprehensive set of proteins.Methods: We obtained plasma samples biobanked from individuals who developed ulcerative colitis later in life (n = 72) and matched healthy controls (n = 140) within a population-based screening cohort. We measured 92 proteins related to inflammation using a proximity extension assay. The biologic relevance of these findings was validated in an inception cohort of patients with ulcerative colitis (n = 101) and healthy controls (n = 50). To examine the influence of genetic and environmental factors on these markers, a cohort of healthy twin siblings of patients with ulcerative colitis (n = 41) and matched healthy controls (n = 37) were explored.Results: Six proteins (MMP10, CXCL9, CCL11, SLAMF1, CXCL11 and MCP-1) were up-regulated (P < .05) in preclinical ulcerative colitis compared with controls based on both univariate and multivariable models. Ingenuity Pathway Analyses identified several potential key regulators, including interleukin-1β, tumor necrosis factor, interferon-gamma, oncostatin M, nuclear factor-κB, interleukin-6, and interleukin-4. For validation, we built a multivariable model to predict disease in the inception cohort. The model discriminated treatment-naïve patients with ulcerative colitis from controls with leave-one-out cross-validation (area under the curve = 0.92). Consistently, MMP10, CXCL9, CXCL11, and MCP-1, but not CCL11 and SLAMF1, were significantly up-regulated among the healthy twin siblings, even though their relative abundances seemed higher in incident ulcerative colitis.Conclusions: A set of inflammatory proteins are up-regulated several years before a diagnosis of ulcerative colitis. These proteins were highly predictive of an ulcerative colitis diagnosis, and some seemed to be up-regulated already at exposure to genetic and environmental risk factors.
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| 10. |
- Bergsten, Eva L., 1969-, et al.
(författare)
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Physical and psychosocial work conditions among baggage handlers in six Swedish airports
- 2012
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Konferensbidrag (refereegranskat)abstract
- Introduction Flight baggage handlers are mainly engaged in sorting luggage or cargo, loading and unloading it to and from the airplanes. The Vocational Training and Working Environment Council, TYA - formed by employer’s and employee’s organizations in the transportation sector - initiated a scientific study in 2009 to investigate the prevalence of musculoskeletal disorders and their suspected determinants in six Swedish airports involving a total of about 1000 handlers in 14 cargo- and handling companies. Encouraged by an initial literature review, the present field study was designed to contain qualitative, questionnaire-based, and observational surveys of working conditions, as well as extensive direct measurements of postures using full-shift inclinometry. This paper reports the design and results of the questionnaire part of the study.MethodAll baggage handlers working at least half-time (n=1044) were encouraged to fill in an extensive questionnaire handed out at the workplace by a research team member. In general the researcher collected the questionnaires at the same occasion. The questionnaire addressed general health, work capacity and physical exposures in relevant handling tasks. It also included a modified version of the Copenhagen Psychosocial Questionnaire (COPSOQ), the Nordic Council of Minister’s Questionnaire (NMQ) on disorders, and the SOFI-questionnaire measuring perceived fatigue.ResultsThe response rate was 73%. The prevalence of musculoskeletal disorders in the back, shoulders and wrists during the last 12 months was 70%, 60% and 45%. Positive effects of devices used for reducing perceived physical load were confirmed. The handlers expressed a low confidence in the leadership, and insufficient feedback, information and influence at work. Fatigue particularly occurred in the dimensions lack of energy and physical discomfort.DiscussionThe observed prevalence of low back pain (70%) is high, and in parity with results among nurses in Sweden (64%; Josephson et al. 1997) and China (56%; Smith et al. 2004). Further examination of questionnaires, interviews and direct posture measurements will identify determinants to consider for intervention to reduce the prevalence of disorders among the baggage handlers.Josephson M, et al. Occup Environ Med 1997;54:681-685.Smith DR, et al. Occup Med 2004;54:579-582
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| 11. |
- Bergsten, Eva L., et al.
(författare)
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Skadefria cargo- och flygplanslastare - slutrapport
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SammanfattningArbetsmiljöprojektet Skadefria cargo- och flygplanslastare har utförts på uppdrag av Svenska Transportarbetareförbundet och Svenska Flygbranschen med syfte att kartlägga flygplanslastarnas arbetsförhållanden och att komma med förslag på förbättringsåtgärder för att minska belastningsrelaterade skador och sjukdomar i branschen.Projektledningsgruppen har bestått av fem personer: Eva Bergsten, ergonom, anställd av projektet; Erik Alphonse, projektledare, TYA; Reidar Pettersson, arbetsmiljökonsult, Arbetsmiljölotsen; Svend Erik Mathiassen, professor, Centrum för belastningsskadeforskning vid Högskolan i Gävle; och Dan Holmberg, regionalt skyddsombud, Transportarbetareförbundet.Projektet som omfattade 14 bolag (11 handling, 3 cargo) på sex flygplatser (Arlanda, Malmö, Göteborg, Växjö, Skavsta och Arvidsjaur) startades våren 2010 och avslutades våren 2012, efter en inledande pilotstudie våren 2010 som finansierades av TYA. Inom projektet har 1 039 enkäter distribuerats med frågor om psykosociala arbetsförhållanden, upplevd arbetsbelastning, trötthet och besvär. Svarsfrekvensen var 72 procent. Heldagsmätningar av arbetsställningar för rygg och armar har genomförts på 5-6 lastare per flygplats samtidigt som lastarna filmats och fyllt i dagböcker. Fokusgrupper har intervjuats och data om till exempel sjukskrivningar och olyckstillbud har samlats in från företagen.Parallellt med den vetenskapliga delen har projektet haft en praktisk del med fyra arbetsgrupper bestående av representanter från både arbetsgivar- och arbetstagarsidan. Grupperna har träffats två gånger per termin och jobbat inom områdena: I) fysisk belastning och arbetsskadestatistik, II) arbetsorganisation, schemaläggning och psykosocial arbetsmiljö, III) hjälpmedel och metoder samt IV) utbildning och utveckling.Våra resultat visar att besvärsfrekvenserna i muskler och leder är relativt höga. Det finns arbetsmoment i lastaryrket som är ogynnsamma och som ökar risken för besvär, framför allt i axlar/skuldra, rygg och handleder/händer. De arbetsuppgifter som en lastare har skiljer sig inte så mycket åt mellan de olika flygplatserna, men det finns betydande skillnader i hur ofta och hur länge uppgifterna förekommer. Vid vissa flygplatser är således flyglastararbetet mera varierat än vid andra, vilket förmodligen har en betydelse för risken att utveckla besvär.Överlag fanns det hjälpmedel för de mest belastande arbetsmomenten, men också brister i hur dessa används.Inom den psykosociala arbetsmiljön visade projektet på ett behov av att förbättra ledarskapet och lastarnas inflytande i planering och genomförande av det egna arbetet. Bättre feedback i form av stöd och uppmuntran från ledare efterfrågades också.Arbetsgrupperna, som löpande delgavs resultaten från den vetenskapliga kartläggningen, utvecklade i enlighet med projektets målsättning ett antal åtgärdsförslag, med stöd i kartläggningen. Förslagen, som presenteras i denna rapport, är av generell natur. Flera av förslagen omfattar ett flertal möjliga delåtgärder och initiativ, som naturligtvis måste anpassas för och prioriteras av det enskilda bolaget utifrån dess egna förutsättningar. Mot bakgrund av våra projektresultat vill vi dock generellt rekommendera samtliga bolag att lägga en viss prioritet på de psykosociala arbetsförhållandena i sitt förbättringsarbete. Det fanns även uppenbara möjligheter att förbättra den fysiska belastningsprofilen, särskilt genom att bredda arbetsinnehållet på vissa flygplatser, och genom en mera effektiv användning av tekniska hjälpmedel. Samtidigt är det viktigt att framhålla att lastaryrket även har många goda sidor i form av ett rörligt och spännande arbete med ett bra socialt klimat.Vår bedömning är att de förslag till förändringar i arbetsmiljö och arbetsvillkor som föreslås i denna rapport skulle leda till en bättre arbetsmiljö men sannolikt också kunna påverka effektiviteten i arbetet i positiv riktning.Projektet Skadefria cargo- och flygplanlastare är föremål för en avhandling vilket betyder att vidare analyser av insamlade data kommer att ske. Resultaten kommer framöver att publiceras i vetenskapliga tidsskrifter.
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| 12. |
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| 13. |
- Castarède, Dimitri, et al.
(författare)
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Development and characterization of the Portable Ice Nucleation Chamber 2 (PINCii)
- 2023
-
Ingår i: Atmospheric Measurement Techniques. - 1867-1381. ; 16:16, s. 3881-3899
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Tidskriftsartikel (refereegranskat)abstract
- The Portable Ice Nucleation Chamber 2 (PINCii) is a newly developed continuous flow diffusion chamber (CFDC) for measuring ice nucleating particles (INPs). PINCii is a vertically oriented parallel-plate CFDC that has been engineered to improve upon the limitations of previous generations of CFDCs. This work presents a detailed description of the PINCii instrument and the upgrades that make it unique compared with other operational CFDCs. The PINCii design offers several possibilities for improved INP measurements. Notably, a specific icing procedure results in low background particle counts, which demonstrates the potential for PINCii to measure INPs at low concentrations ( < 10 L (-1)). High-spatial-resolution wall-temperature mapping enables the identification of temperature inhomogeneities on the chamber walls. This feature is used to introduce and discuss a new method for analyzing CFDC data based on the most extreme lamina conditions present within the chamber, which represent conditions most likely to trigger ice nucleation. A temperature gradient can be maintained throughout the evaporation section in addition to the main chamber, which enables PINCii to be used to study droplet activation processes or to extend ice crystal growth. A series of both liquid droplet activation and ice nucleation experiments were conducted at temperature and saturation conditions that span the spectrum of PINCii's operational conditions ( 50 <= temperature <= 15 degrees C and 100 <= relative humidity with respect to ice <= 160 %) to demonstrate the instrument's capabilities. In addition, typical sources of uncertainty in CFDCs, including particle background, particle loss, and variations in aerosol lamina temperature and relative humidity, are quantified and discussed for PINCii.
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| 14. |
- Collaboration, The PANDA, et al.
(författare)
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Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
- 2016
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Ingår i: European Physical Journal A. - : Springer Publishing Company. - 1434-6001 .- 1434-601X. ; 52:10
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Tidskriftsartikel (refereegranskat)abstract
- Simulation results for future measurements of electromagnetic proton form factors at P ¯ ANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel p¯ p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.p¯ p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
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| 15. |
- Eriksson, Axel, et al.
(författare)
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Particulate PAH Emissions from Residential Biomass Combustion : Time-Resolved Analysis with Aerosol Mass Spectrometry
- 2014
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:12, s. 7143-7150
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Tidskriftsartikel (refereegranskat)abstract
- Time-resolved emissions of particulate polycyclic aromatic hydrocarbons (PAHs) and total organic particulate matter (OA) from a wood log stove and an adjusted pellet stove were investigated with high-resolution time-of-flight aerosol mass spectrometry (AMS). The highest OA emissions were found during the addition of log wood on glowing embers, that is, slow burning pyrolysis conditions. These emissions contained about 1% PAHs (of OA). The highest PAH emissions were found during fast burning under hot air starved combustion conditions, in both stoves. In the latter case, PAHs contributed up to 40% of OA, likely due to thermal degradation of other condensable species. The distribution of PAHs was also shifted toward larger molecules in these emissions. AMS signals attributed to PAHs were found at molecular weights up to 600 Da. The vacuum aerodynamic size distribution was found to be bimodal with a smaller mode (Dva ~ 200 nm) dominating under hot air starved combustion and a larger sized mode dominating under slow burning pyrolysis (Dva ~ 600 nm). Simultaneous reduction of PAHs, OA and total particulate matter from residential biomass combustion may prove to be a challenge for environmental legislation efforts as these classes of emissions are elevated at different combustion conditions.
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| 16. |
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| 17. |
- Glans, Erik, 1980-
(författare)
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Pension reforms and retirement behaviour
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of three self-contained essays. Essay 1. Knowledge about how elderly workers react to changes in pension benefits is important in guiding the design of social security systems. This essay contributes to this knowledge by examining the effect of changes in replacement rates on part-time retirement behaviour in Sweden. During the 1980s, older workers had the option of partial retirement with an income replacement rate of 65 percent. The replacement rate was lowered to 50 percent in 1981 and subsequently returned to 65 percent in 1987. Estimates using a linear probability model with register data from the LINDA database suggest that fewer men and women chose part-time retirement after the reduction in benefit levels in 1981. There was an approximate 4 percentage point drop in the partial retirement propensity among eligible 60 year-old men, and a 5.7 percent drop among women. This corresponds to proportional reductions in the retirement propensity by about 29 and 36 percent, respectively. The probability of part-time retirement increased among men by about 3.5 percentage points once benefit levels returned back in 1987, whereas the partial retirement probability of women remained largely unchanged. Essay 2. The Swedish pension reform 1999-2003 provides an opportunity to study whether and how important economic incentives are for the timing of retirement. The new pension system provides a much closer link between contributions and benefits than the former system. I study whether the reform has led to delayed retirement by examining the retirement patterns of elderly individuals in the Swedish labour force who were differentially affected by the reform. I use duration analysis with annual data from the LINDA database. Discrete time proportional hazard models are estimated. There is a clear downward trend in the retirement hazard, implying delayed retirement, among more recent cohorts. Most of the decline occurs among public sector employees. Essay 3. This essay estimates the effect of a change from a de- fined benefit pension system to a defined contribution pension system on retirement behaviour. This is done by examining the occupational pension reform for Swedish local government employees of 1998-2000. Both anticipatory and post reform behavioral response is studied. Time, age, and occupational category provide identification. Both difference-in-differences and triple differences are estimated using the discrete time proportional hazard model on a large representative sample of 60-64 year-olds in the labour market from 1996 to 2005. Estimates indicate that the retirement hazard increased by about 38 percent in anticipation of the reform, and subsequently dropped by about 60 percent. The post reform effect corresponds for an approximate additional average time in the labour force of about 6.5 months for the treated group in the 60-64 age span. This essay shows that changes in pension schemes that contribute relatively little to total individual pension wealth may have disproportionately large effects on retirement behavior if the schemes provides strong incentives for early retirement.
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| 18. |
- Hallgren, Christoffer, et al.
(författare)
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Classification and properties of non-idealized coastal wind profiles - an observational study
- 2022
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Ingår i: Wind Energy Science. - : Copernicus Publications. - 2366-7443 .- 2366-7451. ; 7:3, s. 1183-1207
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Tidskriftsartikel (refereegranskat)abstract
- Non-idealized wind profiles frequently occur over the Baltic Sea and are important to take into consideration for offshore wind power, as they affect not only the power production but also the loads on the structure and the behavior of the wake behind the turbine. In this observational study, we classified non-idealized profiles as the following wind profiles having negative shear in at least one part of the lidar wind profile between 28 and 300 m: low-level jets (with a local wind maximum in the profile), profiles with a local minimum and negative profiles. Using observations spanning over 3 years, we show that these non-idealized profiles are common over the Baltic Sea in late spring and summer, with a peak of 40 % relative occurrence in May. Negative profiles (in the 28-300 m layer) mostly occurred during unstable conditions, in contrast to low-level jets that primarily occurred in stable stratification. There were indications that the strong shear zone of low-level jets could cause a relative suppression of the variance for large turbulent eddies compared to the peak of the velocity spectra, in the layer below the jet core. Swell conditions were found to be favorable for the occurrence of negative profiles and profiles with a local minimum, as the waves fed energy into the surface layer, resulting in an increase in the wind speed from below.
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| 19. |
- Herstad-Svärd, S., et al.
(författare)
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Ramprogram – Åtgärder för samtidig minimering av alkalirelaterade driftproblem, Etapp 2
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of an increasing amount of biofuel and waste woods has resulted in certainenvironmental advantages, including decreased emissions of fossil CO2, SO2 andmetals. On the other hand, a number of chloride and alkali related operational problemshave occurred which are related to combustion of these fuels.Alkali related operational problems have been studied in a project consisting of twoparts. The overall scope has been to characterise the operational problems and to studymeasures to minimise them. The first part was reported in Värmeforsk report 997 wherethe results were summarised in a table of different measures. In part two, additionalmeasures have been included in the test plan and initial corrosion has been studiedlinked to the different measures. The tests have also in part two been carried out at the12 MW CFB boiler at Chalmers. The effect of the selected measures has beeninvestigated concerning both deposit formation and bed agglomeration, and at the sametime emissions and other operational conditions were characterised.The second part of the project has among other things focused on:• To investigate measures which decrease the content of alkali and chloride in thedeposits, and consequently decrease the risk for corrosion (by investigating theinitial corrosion). Focus was also on trying to explain favourable effects.• To investigate if it is possible to combine a rather low dosage of kaolin and injectionof ammonium sulphate. This was done in order to reduce both bed agglomerationand problems from deposits during combustion of fuels rich in chlorine.• To investigate if co-combustion with sewage sludge, de-inking sludge or peat withhigh ash content, could give similar advantages as conventional additives.• Investigate if ash from PFBC is possible to use as an alternative bed material.By comparing the different measures in part two, it could be concluded that cocombustionof sewage sludge gave the best overall effect. The judgement was based onthe effects concerning bed agglomeration, level of alkali chloride in the flue gas,deposits and initial corrosion. Simultaneous addition of kaolin and ammonia sulphatealso had a favourable impact both in the bed and on the alkali chlorides in the gas phase.Dosage of kaolin did not reduce the effect of injected ammonium sulphate. Cocombustionof peat could also be a very attractive alternative, but it is critical to select asuitable peat type. It is of special concern to avoid peat with a high content of calcium,since it can increase the level of alkali chlorides by reacting with available sulphur.Change of bed material to ash from PFBC can decrease problems with bedagglomeration, but there is a risk of increased deposit formation and corrosion. A boileroperated with high steam data should consequently combine the change of bed materialwith injection of ammonium sulphate or another source of sulphur.Co-combustion of de-inking sludge from pulp and paper production can reduceproblems with bed agglomeration. There is, however, an increased chance of corrosiondue to the high content of calcium. Injection of sulphates may improve the situationconcerning corrosion. The results also showed that low potassium chlorine content in the flue gas decreasesthe risk of corrosion. Increased amount of potassium chlorine content in the flue gaswill not necessary give a high amount of chlorine content in the deposits if there is sulphur in the system.Key words: agglomeration, deposits, corrosion, alkali, kaolin, ammonium sulphate,sludge
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| 20. |
- Höglund, Linda, 1974-, et al.
(författare)
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Energy level scheme of InAs/InxGa1-xAs/GaAs quantum-dots-in-a-well infrared photodetector structures
- 2010
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - Woodbury, NY : American Physical Society. - 1098-0121 .- 1550-235X. ; 82:3, s. 035314-
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Tidskriftsartikel (refereegranskat)abstract
- A thorough investigation of quantum-dots-in-a-well structures for infrared photodetector applications has been performed employing different experimental techniques. The electronic structure of self-assembled InAs quantum dots embedded in an In0.15Ga0.85As/GaAs quantum well (QW) was deduced from photoluminescence (PL) and PL excitation (PLE) spectroscopy. From polarization-dependent PL it was revealed that the quantum dots hold two electron energy levels and two heavy-hole levels. Tunnel capacitance spectroscopy confirmed an electron energy level separation of about 50 meV, and additionally, that the conduction-band ground state and excited state of the dots are twofold and fourfold degenerates, respectively. Intersubband photocurrent spectroscopy, combined with simultaneous interband pumping of the dots, revealed a dominant transition at 150 meV (8.5 mu m) between the ground state of the quantum dots and the excited state of the QW. Results from detailed full three-dimensional calculations of the electronic structure, including effects of composition intermixing and interdot interactions, confirm the experimentally unravelled energy level scheme of the dots and well.
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| 21. |
- Jakobsson, Erik, et al.
(författare)
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Automated Usage Characterization of Mining Vehicles For Life Time Prediction
- 2020
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER. - 2405-8963. ; , s. 11950-11955
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Konferensbidrag (refereegranskat)abstract
- The life of a vehicle is heavily influenced by how it is used, and usage information is critical to predict the future condition of the machine. In this work we present a method to categorize what task an earthmoving vehicle is performing, based on a data driven model and a single standalone accelerometer. By training a convolutional neural network using a couple of weeks of labeled data, we show that a three axis accelerometer is sufficient to correctly classify between 5 different classes with an accuracy over 96% for a balanced dataset with no manual feature generation. The results are also compared against some other machine learning techniques, showing that the convolutional neural network has the highest performance, although other techniques are not far behind. An important conclusion is that methods and ideas from the area of Human Activity Recognition (HAR) are applicable also for vehicles. Copyright (C) 2020 The Authors.
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| 22. |
- Jakobsson, Erik, 1987-, et al.
(författare)
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Data driven modeling and estimation of accumulated damage in mining vehicles using on-board sensors
- 2017
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Ingår i: PHM 2017. Proceedings of the Annual Conference of the Prognostics and Health Management Society 2017, St. Petersburg, Florida, USA, October 2–5, 2017. - : Prognostics and Health Management Society. - 9781936263264 ; , s. 98-107
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Konferensbidrag (refereegranskat)abstract
- The life and condition of a MT65 mine truck frame is to a large extent related to how the machine is used. Damage from different stress cycles in the frame are accumulated over time, and measurements throughout the life of the machine are needed to monitor the condition. This results in high demands on the durability of sensors used. To make a monitoring system cheap and robust enough for a mining application, a small number of robust sensors are preferred rather than a multitude of local sensors such as strain gauges. The main question to be answered is whether a low number of robust on-board sensors can give the required information to recreate stress signals at various locations of the frame. Also the choice of sensors among many different locations and kinds are considered. A final question is whether the data could also be used to estimate road condition. By using accelerometer, gyroscope and strain gauge data from field tests of an Atlas Copco MT65 mine truck, coherence and Lasso-regression were evaluated as means to select which signals to use. ARX-models for stress estimation were created using the same data. By simulating stress signals using the models, rain flow counting and damage accumulation calculations were performed. The results showed that a low number of on-board sensors like accelerometers and gyroscopes could give enough information to recreate some of the stress signals measured. Together with a linear model, the estimated stress was accurate enough to evaluate the accumulated fatigue damage in a mining truck. The accumulated damage was also used to estimate the condition of the road on which the truck was traveling. To make a useful road monitoring system some more work is required, in particular regarding how vehicle speed influences damage accumulation.
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| 23. |
- Jakobsson, Erik, 1987-
(författare)
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Data-driven Condition Monitoring in Mining Vehicles
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Situation awareness is a crucial capability of any autonomous system, including mining vehicles such as drill rigs and mine trucks. Typically situation awareness is interpreted as the capability of an autonomous system to interpret its surroundings and the intentions of other agents. The internal system awareness however, is often not receiving the same focus, even though the success of any given mission is completely dependent of the condition of the agents themselves. The internal system awareness in the form of vehicle health is the focus of this thesis.As the mining industry becomes increasingly automated, and vehicles become increasingly advanced, the need for condition monitoring and prognostics will continue to rise. This thesis explores data-driven methods that estimate the health of mining vehicles to accommodate those needs. We do so by utilizing available sensor signals, common on a large amount of mining vehicles, to make assessments of the current vehicle condition and tasks. The mining industry is characterized by small series of highly specialized vehicles, which affects the possibility to use more traditional prognostic solutions.The resulting health information can be used both to aid in tasks such as maintenance planning, but also as an important input to decision making for the planning system, i.e. how to run the vehicle for minimum wear and damage, while maintaining other mission objectives.The contributions include: a) A method to use operational data to estimate damage on the frame of a mine truck. This is done using system identification to find a model describing stresses in the structure with input from other sensors such as accelerometers, load sensors and pressure sensors. The estimated stress time signal is in turn used to calculate accumulated damage, and is shown to reveal interesting conclusions on driver behavior. b) A method to characterize the different driving tasks by using an accelerometer and a convolutional neural network. We show that the model is capable of classifying the vehicle task correctly in 96 % of the cases. And finally c), a system for underground road monitoring, where a quarter car model and a Kalman filter are used to generate an estimate of the road profile, while positioning the vehicle using inertial measurements and access point signal strength.
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| 24. |
- Jakobsson, Erik, 1987-, et al.
(författare)
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Fatigue Damage Monitoring for Mining Vehicles using Data Driven Models
- 2020
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Ingår i: International Journal of Prognostics and Health Management. - Rochester, NY, United States : Prognostics and Health Management Society. - 2153-2648. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The life and condition of a mine truck frame are related to how the machine is used. Damage from stress cycles is accumulated over time, and measurements throughout the life of the machine are needed to monitor the condition. This results in high demands on the durability of sensors, especially in a harsh mining application. To make a monitoring system cheap and robust, sensors already available on the vehicles are preferred rather than additional strain gauges. The main question in this work is whether the existing on-board sensors can give the required information to estimate stress signals and calculate accumulated damage of the frame. Model complexity requirements and sensors selection are also considered. A final question is whether the accumulated damage can be used for prognostics and to increase reliability. The investigation is performed using a large data set from two vehicles operating in real mine applications. Coherence analysis, ARX-models, and rain flow counting are techniques used. The results show that a low number of available on-board sensors like load cells, damper cylinder positions, and angle transducers can give enough information to recreate some of the stress signals measured. The models are also used to show significant differences in usage by different operators, and its effect on the accumulated damage.
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| 25. |
- Jakobsson, Erik, et al.
(författare)
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Fault Identification in Hydraulic Rock Drills from Indirect Measurement During Operation
- 2021
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER. - 2405-8963. ; , s. 73-78
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Konferensbidrag (refereegranskat)abstract
- This work presents a method for on-line condition monitoring of a hydraulic rock drill, though some of the findings can likely be applied in other applications. A fundamental difficulty for the rock drill application is discussed, namely the similarity between frequencies of internal standing waves and rock drill operation. This results in unpredictable pressure oscillations and superposition, which makes synchronization between measurement and model difficult. To overcome this, a data driven approach is proposed. The number and types of sensors are restricted due to harsh environmental conditions, and only operational data is available. Some faults are shown to be detectable using hand-crafted engineering features, with a direct physical connection to the fault of interest. Such features are easily interpreted and are shown to be robust against disturbances. Other faults are detected by classifying measured signals against a known reference. Dynamic Time Warping is shown to be an efficient way to measure similarity for cyclic signals with stochastic elements from disturbances, wave propagation and different durations, and also for cases with very small differences in measured pressure signals. Together, the two methods enables a step towards condition monitoring of a rock drill, robustly detecting very small changes in behaviour using a minimum amount of sensors. Copyright (C) 2021 The Authors.
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| 26. |
- Jakobsson, Erik, 1987-, et al.
(författare)
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Time Series Fault Classification for Wave Propagation Systems with Sparse Fault Data
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this work Time Series Classification techniques are investigated, and especially their applicability in applications where there are significant differences between the individuals where data is collected, and the individuals where the classification is evaluated. Classification methods are applied to a fault classification case, where a key assumption is that data from a fault free reference case for each specific individual is available. For the investigated application, wave propagation cause almost chaotic changes of a measured pressure signal, and physical modeling is difficult. Direct application of One-Nearest-Neighbor Dynamic Time Warping, a common technique for this kind of problem, and other machine learning techniques are shown to fail for this case and new methods to improve the situation are presented. By using relative features describing the difference from the reference case rather than the absolute time series, improvements are made compared to state-of-the-art time series classification algorithms.
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| 27. |
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| 28. |
- Lapkin, Igor, 1963, et al.
(författare)
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Dual Band MM-Wave Receiver for Onsala 20 m Antenna
- 2014
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Ingår i: Proceedings of the TWENTY-FIFTH INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY, April 27-30, 2014, Moscow, Russia. ; , s. 132-
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Konferensbidrag (refereegranskat)abstract
- We present the design and the first light results for the new dual band receiver (4 mm and 3 mm bands) for Onsala Observatory 20 m antenna. For single dish operation, the receiver uses innovative on-source/off-source optical switch. Within the same optical layout, the switch, in combination with additional optical components, provides 2 calibration loads and sideband measurements possibilities. The optics layout of the receiver uses offset elliptical cold mirrors for both channels whereas the on-off switch employs flat mirrors only. The 3 mm channel employs 2SB dual polarization receiver with OMT, 4-8 GHz IF, x 2pol x (USB+LSB). The cryostat has 4 optical widows made of HDPE with anti-reflection corrugations, two for the signal and two for each frequency band cold load. The cryostat employs a two stage cryocooler RDK 408D2 and uses anti-vibration suspension of the cold-head to minimize impact of the vibrations on the receiver stability. The LO system is based on Gunn oscillator with PLL and two mechanical tuners for broadband operation, providing independently tunable LO power for each polarization. At the conference, we will present details on the receiver optics, cryostat design and the result of the first on-sky observations.
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| 29. |
- Lindgren, Erik, 1981-
(författare)
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One coin - One vote : the rural political power shift that pushed Sweden towards industrialization
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Causal Effect of Political Power on the Provision of Public Education: Evidence from a Weighted Voting SystemWe estimate how political power affects the provision of public education in local governments, using data from a nondemocratic society where voters received votes in proportion to their taxable income. This was the system used in Swedish local governments during the period 1862–1909. We use two different identification strategies, a threshold regression analysis and a generalized event-study design, both of which exploit nonlinearities or discontinuities in the effect of political power between two opposing local elites: agricultural landowners and emerging industrialists. The results suggest that school spending is approximately 90–120% higher if the non-agrarian interest controls all of the votes compared to when landowners have a majority.The Causal Effect of Transport Infrastructure: Evidence from a New Historical DatabaseWe analyze the effect of railroad investments on economic growth and find large effects of having access to railways. For real non-agricultural income, the cumulative treatment effect is approximately 130% after 30 years. We also show that the effect is likely to reflect growth rather than a reorganization of existing economic activity since no spillover effects between treated and untreated regions are found. Our results are consistent with the big push hypothesis that argues that simultaneous and coordinated investment can generate economic growth if there are strong aggregate demand externalities. We corroborate this mechanism by using plant-level data and find that investments in local railways significantly increase local industrial production and employment.The Political Economics of Growth, Labor Control and Coercion: Evidence from a Suffrage Reform Here we analyze the breadth of Sweden’s industrial, economic and social development from the 1860s to the 1910s. By using a novel constructed historical dataset of approximately 2,400 Swedish local governments we find that the change in suffrage affected several outcomes at the local level. These outcomes include factor price manipulation in the form of entry barriers such as investments in local public education and transportation; technology adoption and labor productivity in agriculture and industry; changes in the real wage structure, composition of employment, and the structure of production; organized labor and labor coercion; demographic transition; and persistence in dysfunctional local political institutions. Our results support the idea that political institutions are a key determinant of long-term development and growth. Precipitation and Infant Mortality: Evidence from Sweden 1881–1950I analyze the dynamic effects of precipitation on infant mortality, using a panel dataset containing monthly mortality data from approximately 2,150 Swedish parishes and monthly precipitation levels collected at a number of weather stations around the country. Given that I use data from 1881 to 1950, the size of this novel panel dataset is considerable. Parishes have been matched to the closest weather station for every given month. Given that precipitation, is neither binary nor constant, a binned event-study design is used to estimate the dynamic effects with respect to the precipitation intensity. The results show that increased precipitation decreases infant mortality for both male and female infants. The dynamic effect after 4 months is about 8 percent.
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| 30. |
- Magnusson, Monika, 1965-, et al.
(författare)
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Digitalisering av krisövning : Erfarenheter från CriseIT-projekten
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Genomförandet av övningar är en nyckel till stärkt förmåga att agera effektivt i kris. CriseIT-projekten har haft som mål att bidra till detta genom att skapa möjligheter för kommuner och andra aktörer med krisövningsbehov att öva enklare och oftare.Det finns en önskan om, och en medvetenhet om behoven av, att öva mer än vad som görs i nuläget i många organisationer. Digitala verktyg är ett sätt att göra det möjligt att öva oftare, med lägre resursåtgång och kortare tid för planering och genomförande. Corona-pandemin har ytterligare gjort det tydligt vilka möjligheter digitaliseringen innebär för att effektivisera processer som tidigare varit inramade av tids-och rumsbegränsningar –t.ex. övning.Denna rapport syftar till att på ett lättillgängligt sätt redogöra för och diskutera utmaningar och möjligheter med den digitala övningsprocessen, så som den kommit till uttryck i CriseIT-projekten, genom att beskriva metodiska arbetssätt för design, genomförande och utvärdering av digitala krisövningar samt några perspektiv på implementering av digital övningsmetodik i organisationer. Målgrupp för rapporten är den som arbetar med krisberedskap i offentlig eller privat verksamhet, och som önskar lära sig mer om möjligheten att digitalisera sin övningsprocess. Arbetsrapporten är del av resultatredovisning för CriseIT2.
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| 31. |
- Malmberg, Erik, et al.
(författare)
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Patient-tailored analysis of minimal residual disease in acute myeloid leukemia using next-generation sequencing
- 2017
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Ingår i: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 98:1, s. 26-37
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Tidskriftsartikel (refereegranskat)abstract
- Next-generation sequencing techniques have revealed that leukemic cells in acute myeloid leukemia often are characterized by a limited number of somatic mutations. These mutations can be the basis for the detection of leukemic cells in follow-up samples. The aim of this study was to identify leukemia-specific mutations in cells from patients with acute myeloid leukemia and to use these mutations as markers for minimal residual disease. Leukemic cells and normal lymphocytes were simultaneously isolated at diagnosis from 17 patients with acute myeloid leukemia using fluorescence-activated cell sorting. Exome sequencing of these cells identified 240 leukemia-specific single nucleotide variations and 22 small insertions and deletions. Based on estimated allele frequencies and their accuracies, 191 of these mutations qualified as candidates for minimal residual disease analysis. Targeted deep sequencing with a significance threshold of 0.027% for single nucleotide variations and 0.006% for NPM1 type A mutation was developed for quantification of minimal residual disease. When tested on follow-up samples from a patient with acute myeloid leukemia, targeted deep sequencing of single nucleotide variations as well as NPM1 was more sensitive than minimal residual disease quantification with multiparameter flow cytometry. In conclusion, we here describe how exome sequencing can be used for identification of leukemia-specific mutations in samples already at diagnosis of acute myeloid leukemia. We also show that targeted deep sequencing of such mutations, including single nucleotide variations, can be used for high-sensitivity quantification of minimal residual disease in a patient-tailored manner.
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| 32. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 33. |
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| 34. |
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| 35. |
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| 36. |
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| 37. |
- Pettersson, Carolina, 1980, et al.
(författare)
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KCl-Induced High Temperature Corrosion of the Austenitic Fe-Cr-Ni Alloys 304L and Sanicro 28 at 600 °C
- 2006
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Ingår i: Corrosion Science. ; 48:6, s. 1368-1378
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Tidskriftsartikel (refereegranskat)abstract
- The influence of KCl(s) on the high temperature oxidation of the austenitic alloys 304L and Sanicro 28 at 600 °C in O2 + H2O environment is reported. 0.10 mg/cm2 KCl(s) was added before exposure. The samples are investigated by grazing angle XRD, SEM/EDX, and AES. In the absence of KCl, both alloys show protective behaviour in dry O2. In O2 + H2O environment, alloy 304L suffers local breakaway corrosion while Sanicro 28 still shows protective behaviour. The oxidation of both alloys is strongly accelerated by KCl. KCl reacts with chromium in the normally protective corundum-type oxide, forming K2CrO4. This depletes the scale in chromia and leads to the formation of a non-protective, iron-rich scale. The significance of KCl-induced corrosion in real applications is discussed and the oxidation behaviour of the two steels is compared.
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| 38. |
- Pettersson, Håkan, et al.
(författare)
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Quantum Dots-in-a-Well Infrared Photodetectors-Electronic Structure and Optical Properties
- 2010
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Ingår i: Bulletin of American Physical Society. - : American Physical Society.
-
Konferensbidrag (refereegranskat)abstract
- Quantum dots-in-a-well (DWELL) infrared photodetectors is a new class of nanophotonic devices with the potential of significantly increasing the performance and reducing the cost of infrared detectors. Here we present a comprehensive study of DWELL photodetector structures using a variety of optical techniques (PL, PLE, and PC). Complementary tunnel capacitance measurements support the electronic structure obtained from the optical measurements. A detailed energy level scheme based on the experimental findings is presented and compared to theoretical modeling. The presented work show the importance of combining different electrical and optical techniques to obtain a consistent model of complicated quantum structures which is crucial for the development of future nanophotonic devices.
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| 39. |
- Pettersson, Jesper, 1978, et al.
(författare)
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A pilot plant study of the effect of alkali salts on initial stages of the high temperature corrosion of alloy 304L
- 2004
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Ingår i: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 461-464, s. 965-972
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Tidskriftsartikel (refereegranskat)abstract
- Alloy 304L was exposed for between 15 min to 12 hr in the 12MW CFB research boiler at the Chalmers university of technology using an air-cooled probe. The base fuel consisted of a mixture of 67% wood chips and 33% pellets. In addition to the base fuel experiment, a number of exposures were performed where S and Cl was added to the fuel in the form Of SO2(g) and HCl(aq) in order to control the flue gas chemistry in the superheater region. After the exposures the samples were analysed by ESEM/EDX, XRD and SAM. Burning a mixture of woodchips/pellets without adding sulphur or chlorine results in the formation of K2SO4 deposits on the corrosion probes. When HCl is added to the fuel KCl deposits form. The simultaneous addition of HCl and SO, results in a deposit consisting of a mixture of KCl and K2SO4. In all environments studied an oxide in the 100nm range forms. With time, the oxide becomes covered by ash deposits. After exposure to the biomass flue gas environment, the oxide is enriched in K, especially the outer part. Chlorine is not present in the oxide even when the KCl(s) forms on the surface. It is suggested that potassium chromate formation occurs by the reaction of potassium chloride with chromium oxide.
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| 40. |
- Rutgersson, Anna, 1971-, et al.
(författare)
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Using land-based stations for air–sea interaction studies
- 2020
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Ingår i: Tellus. Series A, Dynamic meteorology and oceanography. - : Informa UK Limited. - 0280-6495 .- 1600-0870. ; 72:1, s. 1-23
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Tidskriftsartikel (refereegranskat)abstract
- In situ measurements representing the marine atmosphere and air-sea interaction are taken at ships, buoys, stationary moorings and land-based towers, where each observation platform has structural restrictions. Air-sea fluxes are often small, and due to the limitations of the sensors, several corrections are applied. Land-based towers are convenient for long-term observations, but one critical aspect is the representativeness of marine conditions. Hence, a careful analysis of the sites and the data is necessary. Based on the concept of flux footprint, we suggest defining flux data from land-based marine micrometeorological sites in categories depending on the type of land influence:1. CAT1: Marine data representing open sea,2. CAT2: Disturbed wave field resulting in physical properties different from open sea conditions and heterogeneity of water properties in the footprint region, and3. CAT3: Mixed land-sea footprint, very heterogeneous conditions and possible active carbon production/consumption.Characterization of data would be beneficial for combined analyses using several sites in coastal and marginal seas and evaluation/comparison of properties and dynamics. Aerosol fluxes are a useful contribution to characterizing a marine micrometeorological field station; for most conditions, they change sign between land and sea sectors. Measured fluxes from the land-based marine station Ostergarnsholm are used as an example of a land-based marine site to evaluate the categories and to present an example of differences between open sea and coastal conditions. At the Ostergarnsholm site the surface drag is larger for CAT2 and CAT3 than for CAT1 when wind speed is below 10m/s. The heat and humidity fluxes show a distinctive distinguished seasonal cycle; latent heat flux is larger for CAT2 and CAT3 compared to CAT1. The flux of carbon dioxide is large from the coastal and land-sea sectors, showing a large seasonal cycle and significant variability (compared to the open sea sector). Aerosol fluxes are partly dominated by sea spray emissions comparable to those observed at other open sea conditions.
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| 41. |
- Singh, B., et al.
(författare)
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Study of doubly strange systems using stored antiprotons
- 2016
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Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 954, s. 323-340
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Tidskriftsartikel (refereegranskat)abstract
- Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions.
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| 42. |
- Thorin, Eva, 1967-, et al.
(författare)
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PERFOMANCE OPTIMIZATION OF THE VÄXTKRAFT BIOGAS PRODUCTION PLANT –THE USE OF MEMBRANE FILTRATION
- 2009
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Ingår i: Proceedings of ICAE'09. ; , s. 594-602
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Konferensbidrag (refereegranskat)abstract
- Today we can see a large potential for biogas production from any kind of organic residue as well as from different crops, farm land residues or graze. However, the technology for biogas production is not optimized and thus not fully cost-effective. To be fully commercially competitive with other types of fuels, efficiency improvements of the process are needed. In the research project BioGasOpt, performed in cooperation between Mälardalen University and industry, performance optimization of the Växtkraft biogas production plant and surrounding systems are studied. In this paper the project will be presented and the possibility for improvements by using membrane filtration to reduce the dry matter in the recirculated water is addressed.In the Växtkraft biogas plant, in Västerås, Sweden, organic wastes from households and restaurants are mixed and fermented with crops from graze land. A lot of water is used in the process and the surplus is filtered off in decanter centrifuges. The decantate from the centrifuges is partly recirculated in the process and the problem is that the content of dry matter in the decantate is increasing and is today around 4 %. In this paper the potential to use membrane filtration to improve the performance of biogas plants is studied. The consequences concerning production capacity, energy use, and operation of the plant are discussed. The first results from tests on using ceramic membrane filters at the Växtkraft biogas plant show that it possible to decrease the content of dry matter in the process water to 2 % at operation temperatures around 100˚C.
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| 43. |
- Yucel, Yasemin Duygu, et al.
(författare)
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Powder-impregnated carbon fibers with lithium iron phosphate as positive electrodes in structural batteries
- 2023
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Ingår i: Composites Science And Technology. - : Elsevier Ltd. - 0266-3538 .- 1879-1050. ; 241
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Tidskriftsartikel (refereegranskat)abstract
- A structural battery is a multifunctional battery that can carry a load while storing energy. Structural batteries have been a cutting-edge research focus in the last decade and are mainly based on polyacrylonitrile (PAN)-carbon fibers (CFs). In this work, positive electrodes based on PAN-carbon fibers were manufactured with powder impregnation (siphon impregnation) technique using a water-based slurry containing lithium iron phosphate (LFP) as the active electrode material and the water-soluble binder polyethylene glycol (PEG). Different coating compositions, electrode-drying temperatures, and coating parameters were investigated to optimize the coating uniformity and the electrochemical performances. Scanning electron microscopy results showed that the electrode materials coat the CFs uniformly, conformably, and individually. Electrochemical characterization of pouch cells shows that the electrodes containing 6 wt% PEG dried at 140 °C have the best battery performance, delivering a first discharge capacity of 151 mAh g−1 and capacity retention higher than 80% after 100 cycles. Moreover, excellent capacity reversibility was achieved when the electrodes were cycled at multiple C-rates attesting to their stability. The results demonstrate that CFs perform excellently as current collectors in positive electrodes.
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