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1.
  • Jakobsson, Johan, et al. (author)
  • Visual cues of oviposition sites and spectral sensitivity of Cydia strobilella L.
  • 2017
  • In: Journal of Insect Physiology. - : Elsevier BV. - 0022-1910. ; 101, s. 161-168
  • Journal article (peer-reviewed)abstract
    • We investigated whether the spruce seed moth (Cydia strobilella L., Tortricidae: Grapholitini), an important pest in seed orchards of Norway spruce (Picea abies (L.) Karst.), can make use of the spectral properties of its host when searching for flowers to oviposit on. Spectral measurements showed that the flowers, and the cones they develop into, differ from a background of P. abies needles by a higher reflectance of long wavelengths. These differences increase as the flowers develop into mature cones. Electroretinograms (ERGs) in combination with spectral adaptation suggest that C. strobilella has at least three spectral types of photoreceptor; an abundant green-sensitive receptor with maximal sensitivity at wavelength λmax = 526 nm, a blue-sensitive receptor with λmax = 436 nm, and an ultraviolet-sensitive receptor with λmax = 352 nm. Based on our spectral measurements and the receptor properties inferred from the ERGs, we calculated that open flowers, which are suitable oviposition sites, provide detectable achromatic, but almost no chromatic contrasts to the background of needles. In field trials using traps of different spectral properties with or without a female sex pheromone lure, only pheromone-baited traps caught moths. Catches in baited traps were not correlated with the visual contrast of the traps against the background. Thus, visual contrast is probably not the primary cue for finding open host flowers, but it could potentially complement olfaction as a secondary cue, since traps with certain spectral properties caught significantly more moths than others.
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2.
  • Saxena, Richa, et al. (author)
  • Genome-wide association analysis identifies loci for type 2 diabetes and triglyceride levels
  • 2007
  • In: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 316:5829, s. 1331-1336
  • Journal article (peer-reviewed)abstract
    • New strategies for prevention and treatment of type 2 diabetes (T2D) require improved insight into disease etiology. We analyzed 386,731 common single-nucleotide polymorphisms (SNPs) in 1464 patients with T2D and 1467 matched controls, each characterized for measures of glucose metabolism, lipids, obesity, and blood pressure. With collaborators (FUSION and WTCCC/UKT2D), we identified and confirmed three loci associated with T2D - in a noncoding region near CDKN2A and CDKN2B, in an intron of IGF2BP2, and an intron of CDKAL1 - and replicated associations near HHEX and in SLC30A8 found by a recent whole-genome association study. We identified and confirmed association of a SNP in an intron of glucokinase regulatory protein (GCKR) with serum triglycerides. The discovery of associated variants in unsuspected genes and outside coding regions illustrates the ability of genome-wide association studies to provide potentially important clues to the pathogenesis of common diseases.
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3.
  • Svensson, Akiko Kishi, et al. (author)
  • Incident diabetes mellitus may explain the association between sleep duration and incident coronary heart disease
  • 2018
  • In: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 61:2, s. 331-341
  • Journal article (peer-reviewed)abstract
    • Aims/hypothesis: Sleep duration is a risk factor for incident diabetes mellitus and CHD. The primary aim of the present study was to investigate, in sex-specific analyses, the role of incident diabetes as the possible biological mechanism for the reported association between short/long sleep duration and incident CHD. Considering that diabetes is a major risk factor for CHD, we hypothesised that any association with sleep duration would not hold for cases of incident CHD occurring before incident diabetes (‘non-diabetes CHD’) but would hold true for cases of incident CHD following incident diabetes (‘diabetes-CHD’). Methods: A total of 6966 men and 9378 women aged 45–73 years from the Malmö Diet Cancer Study, a population-based, prospective cohort, who had answered questions on habitual sleep duration and did not have a history of prevalent diabetes or CHD were included in the analyses. Incident cases of diabetes and CHD were identified using national registers. Sex-specific Cox proportional hazards regression models were stratified by BMI and adjusted for known covariates of diabetes and CHD. Results: Mean follow-up times for incident diabetes (n = 1137/1016 [men/women]), incident CHD (n = 1170/578), non-diabetes CHD (n = 1016/501) and diabetes-CHD (n = 154/77) were 14.2–15.2 years for men, and 15.8–16.5 years for women. In men, short sleep duration (< 6 h) was associated with incident diabetes (HR 1.35, 95% CI 1.01, 1.80), CHD (HR 1.41, 95% CI 1.06, 1.89) and diabetes-CHD (HR 2.34, 95% CI 1.20, 4.55). Short sleep duration was not associated with incident non-diabetes CHD (HR 1.35, 95% CI 0.98, 1.87). Long sleep duration (≥ 9 h) was associated with incident diabetes (HR 1.37, 95% CI 1.03, 1.83), CHD (HR 1.33, 95% CI 1.01, 1.75) and diabetes-CHD (HR 2.10, 95% CI 1.11, 4.00). Long sleep duration was not associated with incident non-diabetes CHD (HR 1.33, 95% CI 0.98, 1.80). In women, short sleep duration was associated with incident diabetes (HR 1.53, 95% CI 1.16, 2.01), CHD (HR 1.46, 95% CI 1.03, 2.07) and diabetes-CHD (HR 2.88, 95% CI 1.37, 6.08). Short sleep duration was not associated with incident non-diabetes CHD (HR 1.29, 95% CI 0.86, 1.93). Conclusions/interpretation: The associations between sleep duration and incident CHD directly reflect the associations between sleep duration and incident diabetes. Incident diabetes may thus be the explanatory mechanism for the association between short and long sleep duration and incident CHD.
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4.
  • Svensson, Glenn, et al. (author)
  • Assessment of genetic and pheromonal diversity of the Cydia strobilella species complex (Lepidoptera: Tortricidae)
  • 2013
  • In: Systematic Entomology. - : Wiley. - 1365-3113 .- 0307-6970. ; 38:2, s. 305-315
  • Journal article (peer-reviewed)abstract
    • Combining pheromone trapping and genetic analyses can be useful whentrying to resolve complexes of closely related insect taxa that are difficult to distinguishbased on morphological characters. Nearctic and Palearctic populations of the spruceseed moth, Cydia strobilella L., have been considered taxonomically synonymoussince 1983, but more recent work revealing distinct sex pheromones for Canadianand Swedish moths suggest that populations in the two regions belong to differentspecies. In order to test this hypothesis, we performed field trapping using differentpheromone lures at ten sites in North America, Europe and Asia, and reconstructedphylogenetic relationships among trapped moths using mitochondrial (cytochromeoxidase subunit I ) and nuclear (elongation factor 1 alpha) DNA sequence data.Trapping data and tree topologies for both genes revealed distinct pherotypes in NorthAmerica and Eurasia. A genetically distinct population from China was investigatedfurther with respect to its sex pheromone. Electrophysiological data indicated thatChinese females produce a deviant ratio of the sex pheromone components (dienicacetates) compared to Swedish females. However, trapping experiments in both areasrevealed a similar broad response profile in males to a wide range of acetate ratios,and these populations should be considered taxonomically synonymous. A previoussuggestion of an agonistic effect on the attraction of C. strobilella males in Swedenwhen adding the corresponding alcohols to the binary acetate blend was also testedin Sweden as well as in China, with no observed effect on attraction of males. In conclusion, our study demonstrates the great potential of using pheromone trappingas a tool for identification and delimitation of taxa within cryptic species complexes.Based on our data, Nearctic and Palearctic populations of C. strobilella should beconsidered different species, and C. youngana Kearfott stat. rev. is resurrected hereas valid name for North American populations, which was the case before the revisionin 1983.
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5.
  • Svensson, Glenn P., et al. (author)
  • Challenges of pheromone-based mating disruption of Cydia strobilella and Dioryctria abietella in spruce seed orchards
  • 2018
  • In: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 91, s. 639-650
  • Journal article (peer-reviewed)abstract
    • Seed orchards function as the primary source of high-quality seeds for reforestation in many European countries, but their seed yields can be severely reduced due to seed- and cone-feeding insects. We evaluated various parameters of pheromone-based mating disruption for control of the moths Cydia strobilella and Dioryctria abietella, which are major pests in European Picea abies seed orchards. We applied different types of pheromone dispensers (rubber septa or wax droplets) at different densities and heights, and with different amounts of active components, covering whole orchards or part of an orchard. The efficacy of the treatment was evaluated by analysing male captures in pheromone-baited assessment traps, and presence of larvae in cones. A dramatic decrease (94–100%) in capture of males in traps occurred in all pheromone-treated plots compared to control plots for both moth species. In contrast, a subsequent reduction in larval numbers in cones was only achieved when wax droplets were used as the dispensing formulation at high density and at the highest pheromone dose tested, and only in half of the trials for each pest species. Electrophysiological recordings using antennae of male C. strobilella indicated elevated pheromone concentrations in a treated plot versus a control plot. Our results show that mating disruption has potential to reduce cone damage in spruce seed orchards caused by C. strobilella and D. abietella, but optimisation of the technique is required to achieve consistent and efficient population suppression of these pests.
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6.
  • Svensson, Thomas, et al. (author)
  • Association of Sleep Duration with All- And Major-Cause Mortality among Adults in Japan, China, Singapore, and Korea
  • 2021
  • In: JAMA Network Open. - : American Medical Association (AMA). - 2574-3805. ; 4:9
  • Journal article (peer-reviewed)abstract
    • Importance: The association between long sleep duration and mortality appears stronger in East Asian populations than in North American or European populations. Objectives: To assess the sex-specific association between sleep duration and all-cause and major-cause mortality in a pooled longitudinal cohort and to stratify the association by age and body mass index. Design, Setting, and Participants: This cohort study of individual-level data from 9 cohorts in the Asia Cohort Consortium was performed from January 1, 1984, to December 31, 2002. The final population included participants from Japan, China, Singapore, and Korea. Mean (SD) follow-up time was 14.0 (5.0) years for men and 13.4 (5.3) years for women. Data analysis was performed from August 1, 2018, to May 31, 2021. Exposures: Self-reported sleep duration, with 7 hours as the reference category. Main Outcomes and Measures: Mortality, including deaths from all causes, cardiovascular disease, cancer, and other causes. Sex-specific hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards regression with shared frailty models adjusted for age and the key self-reported covariates of marital status, body mass index, smoking status, alcohol consumption, physical activity, history of diabetes and hypertension, and menopausal status (for women). Results: For 322721 participants (mean [SD] age, 54.5 [9.2] years; 178542 [55.3%] female), 19419 deaths occurred among men (mean [SD] age of men, 53.6 [9.0] years) and 13768 deaths among women (mean [SD] age of women, 55.3 [9.2] years). A sleep duration of 7 hours was the nadir for associations with all-cause, cardiovascular disease, and other-cause mortality in both men and women, whereas 8 hours was the mode sleep duration among men and the second most common sleep duration among women. The association between sleep duration and all-cause mortality was J-shaped for both men and women. The greatest association for all-cause mortality was with sleep durations of 10 hours or longer for both men (hazard ratio [HR], 1.34; 95% CI, 1.26-1.44) and women (HR, 1.48; 95% CI, 1.36-1.61). Sex was a significant modifier of the association between sleep duration and mortality from cardiovascular disease (χ25= 13.47, P =.02), cancer (χ25= 16.04, P =.007), and other causes (χ25= 12.79, P =.03). Age was a significant modifier of the associations among men only (all-cause mortality: χ25= 41.49, P <.001; cancer: χ25= 27.94, P <.001; other-cause mortality: χ25= 24.51, P <.001). Conclusions and Relevance: The findings of this cohort study suggest that sleep duration is a behavioral risk factor for mortality in both men and women. Age was a modifier of the association between sleep duration in men but not in women. Sleep duration recommendations in these populations may need to be considered in the context of sex and age.
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7.
  • Svensson, Thomas, et al. (author)
  • Plasma concentration of Caspase-8 is associated with short sleep duration and the risk of incident diabetes mellitus
  • 2018
  • In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 103:4, s. 1592-1600
  • Journal article (peer-reviewed)abstract
    • Context: The biological mechanism for the association between sleep duration and incident diabetes mellitus (DM) is unclear. Sleep duration and Caspase-8, a marker of apoptotic activity, have both been implicated in beta cell function.Objective: To investigate the associations between sleep duration and plasma Caspase-8, and incident DM, respectively.Design: Prospective cohort study.Setting: The Malmö Diet and Cancer (MDC) Study is a population-based, prospective study run in the city of Malmö, Sweden.Participants: 4023 individuals from the MDC Study aged 45-68 years at baseline without a history of prevalent DM, and with information on habitual sleep duration.Main outcomes: Incident DM.Results: Mean follow-up time was 17.8 years. Sleep duration was the only behavioural variable significantly associated with plasma Caspase-8. Plasma Caspase-8 was significantly associated with incident DM per standard deviation of its transformed continuous form (hazard ratio [HR]= 1.24, 95% confidence interval [CI] 1.13-1.36), and when dichotomized into high (quartile 4) (HR=1.44, 95%CI: 1.19-1.74) compared to low (quartiles 1-3) concentrations. Caspase-8 interacted with sleep duration; compared to 7-8 hours of sleep and low plasma Caspase-8, individuals with high plasma Caspase-8 and sleep duration <6 hours (HR=3.54, 95%CI: 2.12-5.90), 6-7 hours (HR=1.81, 95%CI: 1.24-2.65), and 8-9 hours (HR=1.54, 95%CI: 1.09-2.18) were at significantly increased risks of incident DM.Conclusions: Sleep duration is associated with plasma Caspase-8. Caspase-8 independently predicts DM years before disease onset and modifies the effect of sleep duration on incident DM. Future studies should investigate if change of sleep duration modifies plasma concentrations of Caspase-8.
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8.
  • Svensson, Thomas, et al. (author)
  • Very short sleep duration reveals a proteomic fingerprint that is selectively associated with incident diabetes mellitus but not with incident coronary heart disease : a cohort study
  • 2024
  • In: BMC Medicine. - 1741-7015. ; 22:1
  • Journal article (peer-reviewed)abstract
    • Background: The molecular pathways linking short and long sleep duration with incident diabetes mellitus (iDM) and incident coronary heart disease (iCHD) are not known. We aimed to identify circulating protein patterns associated with sleep duration and test their impact on incident cardiometabolic disease. Methods: We assessed sleep duration and measured 78 plasma proteins among 3336 participants aged 46–68 years, free from DM and CHD at baseline, and identified cases of iDM and iCHD using national registers. Incident events occurring in the first 3 years of follow-up were excluded from analyses. Tenfold cross-fit partialing-out lasso logistic regression adjusted for age and sex was used to identify proteins that significantly predicted sleep duration quintiles when compared with the referent quintile 3 (Q3). Predictive proteins were weighted and combined into proteomic scores (PS) for sleep duration Q1, Q2, Q4, and Q5. Combinations of PS were included in a linear regression model to identify the best predictors of habitual sleep duration. Cox proportional hazards regression models with sleep duration quintiles and sleep-predictive PS as the main exposures were related to iDM and iCHD after adjustment for known covariates. Results: Sixteen unique proteomic markers, predominantly reflecting inflammation and apoptosis, predicted sleep duration quintiles. The combination of PSQ1 and PSQ5 best predicted sleep duration. Mean follow-up times for iDM (n = 522) and iCHD (n = 411) were 21.8 and 22.4 years, respectively. Compared with sleep duration Q3, all sleep duration quintiles were positively and significantly associated with iDM. Only sleep duration Q1 was positively and significantly associated with iCHD. Inclusion of PSQ1 and PSQ5 abrogated the association between sleep duration Q1 and iDM. Moreover, PSQ1 was significantly associated with iDM (HR = 1.27, 95% CI: 1.06–1.53). PSQ1 and PSQ5 were not associated with iCHD and did not markedly attenuate the association between sleep duration Q1 with iCHD. Conclusions: We here identify plasma proteomic fingerprints of sleep duration and suggest that PSQ1 could explain the association between very short sleep duration and incident DM.
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9.
  • Tchaplyguine, Maxim, et al. (author)
  • Absolute core-level binding energy shifts between atom and solid: The Born-Haber cycle revisited for free nanoscale metal clusters
  • 2008
  • In: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048 .- 1873-2526. ; 166, s. 38-44
  • Journal article (peer-reviewed)abstract
    • Core-level binding energy shifts between the free atom and corresponding large clusters, the latter closely approximating the infinite solid, have been experimentally derived for several elemental metals. The cluster core-level binding energies in question have been determined relative to the vacuum level using synchrotron-based photoelectron spectroscopy. As expected, the experimental shift values show reasonable agreement with those calculated using the thermochemical Born–Haber cycle approach. The largest uncertainty factors defining the discrepancies between the experiment and the model, such as the difference in the multiplet structure of free atoms and the solid, the in some cases indirectly established cluster work functions, and the metal solvation energy, are discussed.
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  • Wang, Hong-Lei, et al. (author)
  • Sex pheromone of the cloaked pug moth, Eupithecia abietaria (Lepidoptera: Geometridae), a pest of spruce cones
  • 2015
  • In: Journal of Applied Entomology. - : Wiley. - 0931-2048 .- 1439-0418. ; 139:5, s. 352-360
  • Journal article (peer-reviewed)abstract
    • The sex pheromone of the cloaked pug moth, Eupithecia abietaria Götze, an important cone-feeding pest in spruce seed orchards in Europe, was investigated. Chemical and electrophysiological analyses of pheromone gland extracts of female moths and analogous analyses of synthetic hydrocarbons and epoxides of chain length C19 and C21 revealed (3Z,6Z,9Z)-3,6,9-nonadecatriene (3Z,6Z,9Z-19:H) and 3Z,6Z-cis-9,10-epoxynonadecadiene (3Z,6Z-cis-9,10-epoxy-19:H) as candidate pheromone components, which were found in a gland extract in a ratio of 95 : 5. In field trapping experiments, conspecific males were only attracted to a combination of 3Z,6Z,9Z-19:H and the (9S,10R)-enantiomer of 3Z,6Z-cis-9,10-epoxy-19:H. The (9R,10S)-enantiomer was not attractive, which is in agreement with studies on other Eupithecia species, for which males have only been attracted by the (9S,10R)-enantiomer of epoxides. Subsequent experiments showed that E. abietaria males were attracted to a wide range of ratios of the two active compounds and that trap catches increased with increasing dose of the binary blend. A two-component bait containing 300 μg 3Z,6Z,9Z-19:H and 33 μg of the (9S,10R)-enantiomer of 3Z,6Z-cis-9,10-epoxy-19:H was efficient for monitoring E. abietaria in spruce seed orchards in southern Sweden, where this species has probably been overlooked as an important pest in the past. With sex pheromones recently identified for two other moths that are major pests on spruce cones, the spruce seed moth, Cydia strobilella L., and the spruce coneworm, Dioryctria abietella Denis & Schiffermüller, pheromone-based monitoring can now be achieved for the whole guild of cone-feeding moths in European spruce seed orchards.
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12.
  • Aasmundtveit, K.E., et al. (author)
  • Structural ordering in phenyl-substituted polythiophenes
  • 2000
  • In: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 33:15, s. 5481-5489
  • Journal article (peer-reviewed)abstract
    • Various substituted poly(phenylthiophene)s have been studied by X-ray diffraction. They are semicrystalline, with very different degrees of crystallinity. Those with para-substituted phenyl groups have a low degree of crystallinity, whereas those with ortho-substituted phenyl groups are more crystalline. The most crystalline materials in this study have two equally long substituents on the phenyl ring, one at the ortho position and the other at the ortho or meta position on the opposite side of the phenyl ring. Poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) was most thoroughly studied, and a structural model is proposed. The structure of PDOPT is quite different from previously studied substituted polythiophenes in that the octyl side chains are directed normal to the thiophene planes. In this way, the conjugated polymer chains are kept separated from each other. Solution-cast and spin-cast PDOPT films are anisotropic, with the octyl side chains oriented normal to the film surface in both cases. This is contrary to the situation for poly(3-alkylthiophene)s, where solution-cast and spin-cast films orient in different ways.
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13.
  • Acosta, Stefan, et al. (author)
  • Epidemiology, risk and prognostic factors in mesenteric venous thrombosis.
  • 2008
  • In: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; Aug 21, s. 1245-1251
  • Journal article (peer-reviewed)abstract
    • BACKGROUND:: Epidemiological reports on risk and prognostic factors in patients with mesenteric venous thrombosis (MVT) are scarce. METHODS:: Patients with MVT were identified through the inpatient and autopsy registry between 2000 and 2006 at Malmö University Hospital. RESULTS:: Fifty-one patients had MVT, diagnosed at autopsy in six. The highest incidence (11.3 per 100 000 person-years) was in the age category 70-79 years. Activated protein C resistance was present in 13 of 29 patients tested. D-dimer at admission was raised in all five patients tested. Multidetector row computed tomography (CT) in the portal venous phase was diagnostic in all 20 patients investigated, of whom 19 were managed conservatively. The median length of resected bowel in 12 patients who had surgery was 0.6 (range 0.1-2.2) m. The overall 30-day mortality rate was 20 per cent; intestinal infarction (P = 0.046), treatment on a non-surgical ward (P = 0.001) and CT not done (P = 0.022) were associated with increased mortality. Cancer was independently associated with long-term mortality: hazard ratio 4.03, 95 per cent confidence interval 1.03 to 15.85; P = 0.046. CONCLUSION:: Portal venous phase CT appeared sensitive in diagnosing MVT. As activated protein C resistance was a strong risk factor, lifelong anticoagulation should be considered. Copyright (c) 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
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  • Admassie, Shimelis, et al. (author)
  • A polymer photodiode using vapour-phase polymerized PEDOT as an anode
  • 2006
  • In: Solar Energy Materials & Solar Cells. ; 90:2, s. 133-141
  • Journal article (peer-reviewed)abstract
    • We report the photovoltaic properties of devices made using a highly conducting polymer electrode, from vapor-phase polymd. poly (3,4-ethylenedioxy) thiophene (VPP PEDOT) on glass substrate as an anode and a polyfluorene copolymer poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2thienyl-2',1'3'-benzothiadiazole)] (APFO-3) mixed with [6,6]-phenyl-C61-butyric acid methylester (PCBM) in the ratio of 1:4 as the active layer. The device performance was compared with that of devices made with PEDOT-PSS on glass substrates. The surfaces of VPP PEDOT were imaged using at. force microscopy (AFM). [on SciFinder (R)]
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18.
  • Althoff, David M., et al. (author)
  • The influence of interaction type and feeding location on the phylogeographic structure of the yucca moth community associated with Hesperoyucca whipplei
  • 2007
  • In: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1095-9513 .- 1055-7903. ; 43:2, s. 398-406
  • Journal article (peer-reviewed)abstract
    • The interactions between herbivorous insects and their host plants have been central in generating diversification in both groups. We used a community of four yucca moth species, monophagous on the host plant Hesperoyucca whipplei (Agavaceae), to examine how the type of interaction and where insects feed within a plant influence phylogeographic structure of herbivorous insects. These four species included two fruit-feeders, one mutualistic and one commensalistic, and two commensalistic stalk-feeders. Surveys based on mtDNA cytochrome oxidase I sequence data demonstrated that the moth species differed in phylogeographic history. Populations of the mutualist pollinator, Tegeticula maculata, exhibited the most subdivision in comparison to the three commensal Prodoxus species (both genera in Lepidoptera, Prodoxidae). Feeding location was also correlated with differences in phylogeographic history through its influence on population sizes and the probability of gene flow. The results suggest that both the outcome of interactions and where insects feed may influence population structure. (C) 2006 Elsevier Inc. All rights reserved.
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21.
  • Anderbrant, Olle, et al. (author)
  • Occurrence of Z- and E-strain Ostrinia nubilalis in Sweden shortly after first detection of the Z-strain
  • In: Journal of Applied Entomology. - 0931-2048.
  • Journal article (peer-reviewed)abstract
    • Introduction: The European corn borer (ECB), Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is a major pest insect in maize. New cultivars and climate change have allowed range expansion of the crop northwards in Europe, and a similar range expansion of associated pests has been predicted. ECB exists as two distinct pheromone strains using different blends of (E)-11-tetradecenyl acetate and (Z)-11-tetradecenyl acetate for sexual communication; in addition, the Z-strain feeds almost exclusively on maize. In Sweden, the maize cropping area has increased tenfold during the last two decades, increasing the potential for spread of the Z-strain, which was recorded for the first time in the country in 2010. Aim of the study/methods: In this study, we performed trapping experiments with strain-specific lures in maize fields in southern Sweden during 2013–2022 to monitor the presence and relative abundance of the two ECB strains and evaluate the potential increase of the Z-strain. Trapping was also performed at least 5 km away from maize fields. Molecular markers were used to verify the strain identity of trapped males and larvae that fed on maize. Results: Catch data revealed that both pheromone strains were present in the major maize cultivation areas of Sweden, as predicted by recent modelling studies. Our data indicate that the flight period of ECB in southern Sweden lasts from the middle of June to late August, with peak flight in July. Catches of both strains were low at all trapping sites and throughout the study period and decreased further during the years following the dry summer of 2018. No Z-strain males were trapped far away from maize fields. Conclusion: Based on our results, and the low levels of ECB-related damage observed in local maize fields, the Z-strain is currently not imposing a threat to Swedish maize growers.
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22.
  • Anderbrant, Olle, et al. (author)
  • Odour signals for detection and control of indoor pyralid moths
  • 2009
  • In: IOBC/WPRS Bulletin. - 1027-3115. ; 41, s. 69-74
  • Journal article (peer-reviewed)abstract
    • Three pyralid moths, the Mediterranean flour moth (Ephestia kuehniella), the almond moth (Ephestia cautella) and the Indian meal moth (Plodia interpunctella), infest food products all over the world and cause severe problems in factories, shops and households. For health and environmentalreasons chemical control becomes more and more restricted. We here present some promising results offering efficient detection and control of these species based on semiochemicals, and line up a number of remaining questions to be answered in order to improve the reliability and competitiveness of the methods used. For P. interpunctella and E. cautella we found that more complex pheromone blends were superior to the commercially available one-component blend in attracting males, andshould be used if increased sensitivity is desired. The almond moth, males as well as females, can be trapped in buckets with tap water, which will give an estimate of the population level without use of pheromone traps. All three species show positive response to odours identified from chocolate, and this could possibly be developed further and used to determine relative population densities. For population suppression the pheromone-mediated mating disruption technique was employed inlocalities with infestations of all three species. Based on several indirect methods to estimate the population densities we conclude that this technique has a large potential for controlling all three mothspecies.
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  • Andersson, Henrik, et al. (author)
  • Apoptotic neutrophils augment the inflammatory response to Mycobacterium tuberculosis infection in human macrophages
  • 2014
  • In: PLOS ONE. - : PLOS. - 1932-6203. ; 9:7
  • Journal article (peer-reviewed)abstract
    • Macrophages in the lung are the primary cells being infected by Mycobacterium tuberculosis (Mtb) during the initial manifestation of tuberculosis. Since the adaptive immune response to Mtb is delayed, innate immune cells such as macrophages and neutrophils mount the early immune protection against this intracellular pathogen. Neutrophils are short-lived cells and removal of apoptotic cells by resident macrophages is a key event in the resolution of inflammation and tissue repair. Since anti-inflammatory activity is not compatible with effective immunity to intracellular pathogens, we therefore investigated how uptake of apoptotic neutrophils modulates the function of Mtb-activated human macrophages. We show that Mtb infection exerts a potent proinflammatory activation of human macrophages with enhanced gene activation and release of proinflammatory cytokines and that this response was augmented by apoptotic neutrophils. The enhanced macrophage response is linked to apoptotic neutrophil-driven activation of the NLRP3 inflammasome and subsequent IL-1β signalling. We also demonstrate that apoptotic neutrophils not only modulate the inflammatory response, but also enhance the capacity of infected macrophages to control intracellular growth of virulent Mtb. Taken together, these results suggest a novel role for apoptotic neutrophils in the modulation of the macrophage-dependent inflammatory response contributing to the early control of Mtb infection.
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24.
  • Andersson, Martin N, et al. (author)
  • Characterization of olfactory sensory neurons in the white clover seed weevil, Apion fulvipes (Coleoptera: Apionidae).
  • 2012
  • In: Journal of Insect Physiology. - : Elsevier BV. - 1879-1611 .- 0022-1910. ; 58:10, s. 1325-1333
  • Journal article (peer-reviewed)abstract
    • Seed-eating Apion weevils (Coleoptera: Apionidae) cause large economic losses in white and red clover seed production across Europe. Monitoring and control of clover weevils would be facilitated by semiochemical-based methods. Until now, however, nothing was known about physiological or behavioral responses to semiochemicals in this insect group. Here we analyzed the antenna of the white clover (Trifolium repens L.) specialist Apion fulvipes Geoffroy with scanning electron microscopy, and used single sensillum recordings with a set of 28 host compounds to characterize 18 classes of olfactory sensory neurons (OSNs). Nine of the OSN classes responded strongly to synthetic compounds with high abundance in clover leaves, flowers, or buds. Eight classes responded only weakly to the synthetic stimuli, whereas one collective class responded exclusively to volatiles released from a crushed clover leaf. The OSNs showed a remarkable degree of specificity, responding to only one or a few chemically related compounds. In addition, we recorded a marked difference in the temporal dynamics of responses between different neurons, compounds, and doses. The identified physiologically active compounds will be screened for behavioral activity, with the ultimate goal to develop an odor-based control strategy for this pest.
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25.
  • Andersson, Tomas, et al. (author)
  • Photon energy influence on valence photoelectron spectra of silver clusters
  • 2012
  • In: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 388:15, s. 152028-
  • Journal article (peer-reviewed)abstract
    • Silver clusters in the size range of ∼102 constituent atoms have been studied using photoelectron spec-troscopy. The 5s and 4d valence bands have been probed with 40 and 60.5 eV photon energies. Differences in the valence band spectral features have been observed and are discussed in view of earlier results on copper clusters and in terms of differences in mean free path for electrons of different energies.
  •  
26.
  • Andersson, Tomas, et al. (author)
  • Plasmon single- and multi-quantum excitation in free metal clusters as seen by photoelectron spectroscopy
  • 2011
  • In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 134:9, s. 094511-
  • Journal article (peer-reviewed)abstract
    • Plasmons are investigated in free nanoscale Na, Mg, and K metal clusters using synchrotron radiation-based x-ray photoelectron spectroscopy. The core levels for which the response from bulk and surface atoms can be resolved are probed over an extended binding energy range to include the plasmon loss features. In all species the features due to fundamental plasmons are identified, and in Na and K also those due to either the first order plasmon overtones or sequential plasmon excitation are observed. These features are discussed in view of earlier results for planar macroscopic samples and free clusters of the same materials.
  •  
27.
  • Andersson, Tomas, et al. (author)
  • The electronic structure of free aluminum clusters: Metallicity and plasmons
  • 2012
  • In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 136:20
  • Journal article (peer-reviewed)abstract
    • The electronic structure of free aluminum clusters with similar to 3-4 nm radius has been investigated using synchrotron radiation-based photoelectron and Auger electron spectroscopy. A beam of free clusters has been produced using a gas-aggregation source. The 2p core level and the valence band have been probed. Photoelectron energy-loss features corresponding to both bulk and surface plasmon excitation following photoionization of the 2p level have been observed, and the excitation energies have been derived. In contrast to some expectations, the loss features have been detected at energies very close to those of the macroscopic solid. The results are discussed from the point of view of metallic properties in nanoparticles with a finite number of constituent atoms. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4718362]
  •  
28.
  • Aspenberg, Per, 1949-, et al. (author)
  • Artrosskolan : evidensen måste stärkas
  • 2018
  • In: Läkartidningen. - : Läkartidningen Förlag AB. - 0023-7205 .- 1652-7518. ; 115
  • Journal article (pop. science, debate, etc.)
  •  
29.
  • Assadi, A., et al. (author)
  • Interaction of planar polymer Schottky barrier diodes with gaseous substances
  • 1994
  • In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 20:1, s. 71-77
  • Journal article (peer-reviewed)abstract
    • Conducting polymers appear very attractive as sensor materials either as the gas-sensitive component or as a matrix for easy immobilization of a specific substrate. The planar Schottky barrier diode with poly(3-octylthiophene), P3OT, as the semiconductor is used as a sensor for the detection of different gas species. The shifts in the current-voltage (C-V) characteristics as well as the C-V characteristics of the diodes due to water and ethanol vapour, ammonia gas and nitric oxide gases are studied. Nitric oxide and ammonia give the largest and most specific changes of the C-V characteristics. Nitric oxide has a doping effect, which increases the reverse current, while ammonia is the only gas that causes a negative change in the forward bias current of the I-V curve. The planar configuration of the Schottky barrier diode facilitates the absorption of gaseous species in the environment, and provides a simple method for production of gas sensors.
  •  
30.
  • Aurand, Bastian, et al. (author)
  • A setup for studies of laser-driven proton acceleration at the Lund Laser Centre
  • 2015
  • In: Laser and Particle Beams. - 0263-0346. ; 33:1, s. 59-64
  • Journal article (peer-reviewed)abstract
    • We report on a setup for the investigation of proton acceleration in the regime of target normal sheath acceleration. The main interest here is to focus on stable laser beam parameters as well as a reliable target setup and diagnostics in order to do extensive and systematic studies on the acceleration mechanism. A motorized target alignment system in combination with large target mounts allows for up to 340 shots with high repetition rate without breaking the vacuum. This performance is used to conduct experiments with a split mirror setup exploring the effect of spatial and temporal separation between the pulses on the acceleration mechanism and on the resulting proton beam.
  •  
31.
  •  
32.
  • Baev, A, et al. (author)
  • Picturing molecular femtosecond processes through an ultra-fast controllable X-ray shutter
  • 2003
  • In: Chemical Physics. - 0301-0104 .- 1873-4421. ; 289, s. 51-56
  • Journal article (peer-reviewed)abstract
    • We show that frequency detuning in a resonant X-ray scattering experiment acts as an X-ray camera shutter by regulating the duration time of the scattering process. The camera shutter can be used to select processes at different time scales for observation. This is illustrated by a resonant Auger study of the ultra-fast dissociation of the core-excited HF molecule. We present experimental results and first principle simulations of the molecular fraction in the resonant Auger spectra of HF which is a dynamical parameter that well illustrates X-ray shutter controlled dissociation.
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33.
  •  
34.
  •  
35.
  • Benetou, V, et al. (author)
  • Mediterranean diet and incidence of hip fractures in a European cohort
  • 2013
  • In: Osteoporosis International. - : Springer London. - 0937-941X .- 1433-2965. ; 24:5, s. 1587-1598
  • Journal article (peer-reviewed)abstract
    • Prevention of hip fractures is of critical public health importance. In a cohort of adults from eight European countries, evidence was found that increased adherence to Mediterranean diet, measured by a 10-unit dietary score, is associated with reduced hip fracture incidence, particularly among men. INTRODUCTION: Evidence on the role of dietary patterns on hip fracture incidence is scarce. We explored the association of adherence to Mediterranean diet (MD) with hip fracture incidence in a cohort from eight European countries. METHODS: A total of 188,795 eligible participants (48,814 men and 139,981 women) in the European Prospective Investigation into Cancer and nutrition study with mean age 48.6 years (±10.8) were followed for a median of 9 years, and 802 incident hip fractures were recorded. Diet was assessed at baseline through validated dietary instruments. Adherence to MD was evaluated by a MD score (MDs), on a 10-point scale, in which monounsaturated were substituted with unsaturated lipids. Association with hip fracture incidence was assessed through Cox regression with adjustment for potential confounders. RESULTS: Increased adherence to MD was associated with a 7 % decrease in hip fracture incidence [hazard ratio (HR) per 1-unit increase in the MDs 0.93; 95 % confidence interval (95 % CI) = 0.89-0.98]. This association was more evident among men and somewhat stronger among older individuals. Using increments close to one standard deviation of daily intake, in the overall sample, high vegetable (HR = 0.86; 95 % CI = 0.79-0.94) and high fruit (HR = 0.89; 95 % CI = 0.82-0.97) intake was associated with decreased hip fracture incidence, whereas high meat intake (HR = 1.18; 95 % CI = 1.06-1.31) with increased incidence. Excessive ethanol consumption (HR high versus moderate = 1.74; 95 % CI = 1.32-2.31) was also a risk factor. CONCLUSIONS: In a prospective study of adults, increased adherence to MD appears to protect against hip fracture occurrence, particularly among men.
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36.
  • Bergersen, Henrik, et al. (author)
  • First observation of vibrations in core-level photoelectron spectra of free neutral molecular clusters
  • 2006
  • In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 429:1-3, s. 109-113
  • Journal article (peer-reviewed)abstract
    • Core-level photoelectron spectra of free neutral methane clusters have been recorded. These spectra exhibit well-resolved surface and bulk features as well as vibrational fine structure. The vibrational structure in the cluster signal is well reproduced by a theoretical model that assumes independent contributions from inter- and intramolecular modes. The intramolecular contribution to the vibrational line-shape is taken to be equal to that of the monomer in the gas phase, while the intermolecular part is simplified to line broadening. An estimate of the cluster size has been made on the basis of the observed surface-to-bulk intensity ratio.
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37.
  • Bergersen, Henrik, 1978- (author)
  • Free Neutral Clusters and Liquids Studied by Electron Spectroscopy and Lineshape Modeling
  • 2008
  • Doctoral thesis (other academic/artistic)abstract
    • The electronic and geometrical structure of free neutral clusters and liquids have been studied using synchrotron-radiation based photoelectron and Auger electron spectroscopy in combination with lineshape modeling. A novel experimental setup has been developed for studies of liquids, based on the liquid microjet technique. Theoretical lineshapes have been computed using both classical (molecular dynamics) and quantum mechanical (mainly density functional theory) methods.Clusters are finite ensembles of atoms or molecules, ranging in size from a few to several thousand atoms. Apart from being fundamentally interesting, clusters are also promising as building blocks for nano-technology. In this thesis results are presented for rare-gas and molecular clusters, ranging from weakly van-deer-Waals bonded to hydrogen bonded. It is shown that the combination of core-level photoelectron spectroscopy (XPS) and lineshape modeling can be used to estimate the sizes of clusters. A model for treating the effect of inter-molecular nuclear relaxation upon ionization is proposed. The structure of single-component molecular clusters are investigated by molecular dynamics simulations, validated against XPS data. Finally, the radial structure of a two-component molecular cluster is investigated by XPS.Liquids have been studied for centuries, but still many questions remain regarding the microscopic properties. With the recent development of the liquid microjet technique, new insight into the atomic structure can be obtained. In this thesis we study aqueous solutions using photoelectron and Auger electron spectroscopy (AES). We investigate the structure of surface active molecules by XPS, study the Auger decay after core-level ionization in aqueous potassium chloride (KCl), and follow the changes in molecular structure of glycine as a function of pH.
  •  
38.
  •  
39.
  • Bergersen, Henrik, et al. (author)
  • Two size regimes of methanol clusters produced by adiabatic expansion
  • 2006
  • In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 125:18, s. 184303-
  • Journal article (peer-reviewed)abstract
    • Free neutral methanol clusters produced by adiabatic expansion have been studied by photoelectron spectroscopy and line shape modeling. The results show that clusters belonging to two distinct size regimes can be produced by changing the expansion conditions. While the larger size regime can be well described by line shapes calculated for clusters consisting of hundreds of molecules, the smaller size regime corresponds to methanol oligomers, predominantly of cyclic structure. There is little contribution from dimers to the spectra.
  •  
40.
  • Bergström, Ulrica, 1970-, et al. (author)
  • Fracture mechanisms and fracture pattern in men and women aged 50 years and older : a study of a 12-year population-based injury register, Umeå, Sweden
  • 2008
  • In: Osteoporosis International. - London : Springer International. - 0937-941X .- 1433-2965. ; 19:9, s. 1267-1273
  • Journal article (peer-reviewed)abstract
    • Summary: In a study of a 12-year population-based injury register, Umeå, Sweden, we analyzed the fracture mechanisms and fracture pattern in men and women 50 years and older. Low-energy trauma was responsible for the major and costliest part of the fracture panorama, but the pattern differs between age groups. Introduction: Osteoporosis-related fracture is a major health problem: the number of hip fractures is expected to double to 2030. While osteoporosis is one of many risk factors, trauma is almost always involved. Therefore, we analyzed injury mechanisms in patients aged over 50. Methods: We registered injury mechanism, cause, diagnosis in all trauma patients at Umeå University hospital, Sweden. This population-based register (1993–2004) comprises a total of 113,668 injuries (29,189 fractures). Patients ≥50 years contributed to 13,279 fractures. Results: Low-energy trauma (fall <1 m) caused 53% of all fractures ≥50 years and older. In those over 75 low-energy trauma caused >80%. The seasonal variation of fractures was maximally 25%. With increasing age, proximal fractures became more common, in both upper and lower extremities. Proximal locations predominate in older age groups. Conclusions: Low-energy trauma was responsible for the largest and costliest part of the fracture panorama. In fact, almost all fractures in middle-aged and old people were caused by low-energy mechanisms; thus, most fractures in these patients have a fragility component, and the contribution of osteoporosis-related fractures is more important than previously thought. A better understanding of injury mechanisms also in low-energy trauma is a prerequisite for preventive interventions.
  •  
41.
  • Bergström, Ulrica, et al. (author)
  • Fracture panorama in Umeå
  • 2006
  • In: Läkartidningen. - 0023-7205. ; 103:40, s. 2967-8
  • Journal article (peer-reviewed)
  •  
42.
  • Bergström, Ulrica, 1970-, et al. (author)
  • The hip fracture incidence curve is shifting to the right : a forecast of the age-quake
  • 2009
  • In: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 80:5, s. 520-524
  • Journal article (peer-reviewed)abstract
    • Background The number of hip fractures has doubled in the last 30–40 years in many countries. Age-adjusted incidence has been reported to be decreasing in Europe and North America, but is there a decreasing trend in all age groups? Patients and methods This population-based study included all hip-fracture patients over 50 years of age (a total of 2,919 individuals, 31% of whom were men) admitted to Umeå University Hospital, Sweden, from 1993 through 2005. Results The incidence of hip fracture declined between the periods 1993–1996 and 2001–2005: from 706 to 625 hip fractures per 105 women and from 390 to 317 hip fractures per 105 men. However, there was a 114% increase in the number of fractures in women aged 90 or older (12 and 25 hip fractures/year, respectively, in the two time periods). For the period 2001–05, women ≥ 90 years of age accounted for almost the same numbers of hip fractures as women aged 75–79 (27 fractures/year). The rate increased during this period, from 2,700 per 105 women to 3,900 per 105 women > 90 years. In men there were declining trends for both relative and absolute numbers. Interpretation Although age-adjusted incidence declined in the population > 50 years of age, absolute fracture rate and incidence increased in the very old. Women over 90 now have the same absolute number of hip fractures every year as women aged 75–79 years. There was a right-shift in hip fracture distribution towards the oldest old, probably due to an increased number of octo/nonagenarians, a new population of particularly frail old people that hardly existed earlier. Better health among septuagenarians may also have delayed the age at which fractures occurred. This changing pattern will strain orthopedic and geriatric resources even more.
  •  
43.
  • Bjarnason, Thordur, et al. (author)
  • One-Year Follow-up After Open Abdomen Therapy With Vacuum-Assisted Wound Closure and Mesh-Mediated Fascial Traction
  • 2013
  • In: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 37:9, s. 2031-2038
  • Journal article (peer-reviewed)abstract
    • Open abdomen (OA) therapy frequently results in a giant planned ventral hernia. Vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) enables delayed primary fascial closure in most patients, even after prolonged OA treatment. Our aim was to study the incidence of hernia and abdominal wall discomfort 1 year after abdominal closure. A prospective multicenter cohort study of 111 patients undergoing OA/VAWCM was performed during 2006-2009. Surviving patients underwent clinical examination, computed tomography (CT), and chart review at 1 year. Incisional and parastomal hernias and abdominal wall symptoms were noted. The median age for the 70 surviving patients was 68 years, 77 % of whom were male. Indications for OA were visceral pathology (n = 40), vascular pathology (n = 22), or trauma (n = 8). Median length of OA therapy was 14 days. Among 64 survivors who had delayed primary fascial closure, 23 (36 %) had a clinically detectable hernia and another 19 (30 %) had hernias that were detected on CT (n = 18) or at laparotomy (n = 1). Symptomatic hernias were found in 14 (22 %), 7 of them underwent repair. The median hernia widths in symptomatic and asymptomatic patients were 7.3 and 4.8 cm, respectively (p = 0.031) with median areas of 81.0 and 42.9 cm(2), respectively (p = 0.025). Of 31 patients with a stoma, 18 (58 %) had a parastomal hernia. Parastomal hernia (odds ratio 8.9; 95 % confidence interval 1.2-68.8) was the only independent factor associated with an incisional hernia. Incisional hernia incidence 1 year after OA therapy with VAWCM was high. Most hernias were small and asymptomatic, unlike the giant planned ventral hernias of the past.
  •  
44.
  • Björklund, Henrik, et al. (author)
  • Controlled Linear Programming: Boundedness and Duality
  • 2004
  • Reports (other academic/artistic)abstract
    • Computer supported work is often stressful and inadequate computer sys-tems and poor usability contribute to the problem. Still the work situation, and work environment of users are seldom considered when developing computer systems, and it is difficult to incorporate the ideas of User Centred Systems Design (UCSD) in practice. Hence, this research addresses the dif-ficulty in integrating usability, UCSD and occupational health issues in IT systems development in order to improve the resulting work situation and well-being of users. How do basic values and perspectives of stakeholders in systems development projects affect the work with UCSD, usability and users’ health issues in the organisations studied?This research aims at influencing systems development in practice; hence, research is carried out in real life settings with an action research approach. Data is gathered and analysed with a qualitative research approach with in-terview studies, meetings with stakeholders, analysis of documentation, ob-servations and field studies. The theoretical framework adheres to situated action, participatory design, and UCSD that stresses the importance of in-volving users in the design process.This research shows that several basic values and perspectives affect sys-tems development and hinder the usability work, for example, the perspec-tive on user representatives, the value of rationality and objectivity, and the perspective underpinning descriptions and discourse on work. Moreover, this research indicates that the strong business values of automation, efficiency and customer satisfaction shape the development of new technology, and ultimately the tasks and work practices of the civil servants. In short, the studies show that there are some contradictions in business values and the implementation of user-centred systems design, usability and health issues in systems development.Attitudes and perspectives are not easily changed, and change comes gradually. In these organisations, we continuously discuss the integration of health issues in systems development, and by introducing and changing the models of systems development these will hopefully enable communication and change forwards of new perspectives and values. However, a focus on models alone is insufficient and therefore we need to develop a systematic approach to include reflection and new perspectives. Perhaps the reflection itself would help us see our values and perspectives and to alter them?
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45.
  •  
46.
  •  
47.
  • Björklund Svensson, Jonas, et al. (author)
  • Double-bunches for two-color soft X-ray free-electron laser at the MAX IV Laboratory
  • 2018
  • In: Proceedings of FEL2017, Santa Fe, NM, USA. - 9783954501793 ; , s. 269-272
  • Conference paper (other academic/artistic)abstract
    • The ability to generate two-color free-electron laser (FEL) radiation enables a wider range of user experiments than just single-color FEL radiation. There are different schemes for generating the two colors, the original being to use a single bunch and two sets of undulators with different K-parameters. An alternative scheme was recently shown, where two separate bunches in the same RF bucket are used for lasing at different wavelengths in a single set of undulators. We here investigate the feasibility of accelerating and compressing a double-bunch time structure generated in the photocathode electron gun for subsequent use in a soft X-ray FEL at the MAX IV Laboratory.
  •  
48.
  • Björklund Svensson, Jonas, et al. (author)
  • Driver-witness-bunches for plasma-wakefield acceleration at the MAX IV Linear Accelerator
  • 2017
  • In: IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference. - 9783954501823 ; , s. 1743-1746
  • Conference paper (other academic/artistic)abstract
    • Beam-driven plasma-wakefield acceleration is an acceleration scheme promising accelerating fields of at least two to three orders of magnitude higher than in conventional radiofrequency accelerating structures. The scheme relies on using a charged particle bunch (driver) to drive a non-linear plasma wake, into which a second bunch (witness) can be injected at an appropriate distance behind the first, yielding a substantial energy gain of the witness bunch particles. This puts very special demands on the machine providing the particle beam. In this article, we use simulations to show that, if driver-witness-bunches can be generated in the photocathode electron gun, the MAX IV Linear Accelerator could be used for plasma-wakefield acceleration.
  •  
49.
  • Björklund Svensson, Jonas, et al. (author)
  • Low-divergence femtosecond X-ray pulses from a passive plasma lens
  • 2021
  • In: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2481 .- 1745-2473. ; 17:5, s. 639-645
  • Journal article (peer-reviewed)abstract
    • Electron and X-ray beams originating from compact laser-wakefield accelerators have very small source sizes that are typically on the micrometre scale. Therefore, the beam divergences are relatively high, which makes it difficult to preserve their high quality during transport to applications. To improve on this, tremendous efforts have been invested in controlling the divergence of the electron beams, but no mechanism for generating collimated X-ray beams has yet been demonstrated experimentally. Here we propose and realize a scheme where electron bunches undergoing focusing in a dense, passive plasma lens can emit X-ray pulses with divergences approaching the incoherent limit. Compared with conventional betatron emission, the divergence of this so-called plasma lens radiation is reduced by more than an order of magnitude in solid angle, while maintaining a similar number of emitted photons per electron. This X-ray source offers the possibility of producing brilliant and collimated few-femtosecond X-ray pulses for ultra-fast science, in particular for studies based on X-ray diffraction and absorption spectroscopy. X-ray pulses with low divergences are produced in a laser-wakefield accelerator by focusing electron bunches in a dense passive plasma lens.
  •  
50.
  • Björklund Svensson, Jonas, et al. (author)
  • Third-order double-achromat bunch compressors for broadband beams
  • 2019
  • In: Physical Review Accelerators and Beams. - 2469-9888. ; 22:10
  • Journal article (peer-reviewed)abstract
    • Many state-of-the-art applications for linear accelerators, such as free-electron lasers (FELs) and plasma-wakefield accelerators (PWFAs), require small normalized emittances, and PWFAs in particular are very sensitive to transverse slice offsets along the beam. Dispersive systems, such as bunch compressors, can cause different chromatic aberrations, one of which yields transverse slice offsets. In this paper, we show a design approach to double-achromat bunch compressors which greatly reduces different chromatic aberrations and mitigates coherent synchrotron radiation effects.
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