| 1. |
- Joas, Erik, et al.
(författare)
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Effect of CYP2C19 polymorphisms on antidepressant prescription patterns and treatment emergent mania in bipolar disorder.
- 2023
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Ingår i: The pharmacogenomics journal. - : Springer Science and Business Media LLC. - 1473-1150 .- 1470-269X. ; 23:1, s. 28-35
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Tidskriftsartikel (refereegranskat)abstract
- Antidepressant medication is used extensively to treat bipolar depression despite uncertain efficacy. The cytochrome P450 (CYP) 2C19 enzyme metabolize several antidepressants, and polymorphisms in the corresponding gene CYP2C19 influence plasma concentration and hence treatment outcomes in major depressive disorder. Here, we investigate if CYP2C19 polymorphisms are associated with antidepressant treatment patterns and the risk of mania when antidepressants are used in bipolar disorder. Two single nucleotide polymorphisms (rs4244285 and rs12248560) were used to classify 5019 bipolar disorder patients into CYP2C19 metabolic phenotypes ranging from poor to ultra-rapid metabolizers. We used Swedish national registry data 2005-2017 on dispensed medications and inpatient care to estimate risks for early-treatment persistence, treatment discontinuation, switching to a new antidepressant medication, and mania within 3 months of treatment initiation in patients treated with citalopram, escitalopram, sertraline, amitriptyline, and clomipramine. Metabolic phenotypes of CYP2C19 were not robustly associated with the investigated treatment outcomes based on dispense patterns. Slower metabolism was associated with an increased risk of treatment emergent mania for sertraline (hazard ratio [HR]=1.3, 95% CI=1.04-1.62, p=0.02) and the tricyclic antidepressants amitriptyline and clomipramine (HR=1.46, 95% CI=1.05-2.02, p=0.024). In a large study of the impact of CYP2C19 metabolic phenotypes on antidepressant treatment of bipolar depression, we found an association between slower CYP2C19 metabolism and higher risk of treatment emergent mania, which is a step towards personalized risk assessments. There were, however, no clear associations with early treatment persistence, treatment discontinuation, and switching to a new antidepressant.
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| 2. |
- Ahlbeck Bergendahl, Ida, et al.
(författare)
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Fisk- och skaldjursbestånd i hav och sötvatten 2016 : Resursöversikt
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES).De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.Rapporten omfattar 41 fiskarter uppdelade i olika bestånd, samt sju skal- och blötdjursarter.Nytt för årets upplaga är kapitlet om ekosystemtjänster. Avsnittet beskriver de fördelar människan får genom ekosystemen, till exempel hur fisk och skaldjur kommer till nytta för människan genom föda, rekreation och biologisk mångfald. Nytt för i år är också att rapportens diagram och figurer anpassats för läsare med defekt färgseende.Översikten är utarbetad av SLU Aqua på uppdrag av Havs- och vattenmyndigheten.
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| 3. |
- Aidas, Kestutis, et al.
(författare)
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The Dalton quantum chemistry program system
- 2014
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Ingår i: WIREs Computational Molecular Science. - : Wiley. - 1759-0876 .- 1759-0884. ; 4:3, s. 269-284
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Tidskriftsartikel (refereegranskat)abstract
- Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied using linear-scaling and massively parallel algorithms. Dalton is distributed at no cost from for a number of UNIX platforms.
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| 4. |
- Andersson, Malte, 1941, et al.
(författare)
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”Minskande befolkning är inte problemet”
- 2020
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Ingår i: Dagens Nyheter. ; :1 augusti, DN-debatt
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Nätverket Population Matters Sweden: En uppmärksammad studie i The Lancet pekar mot en lägre befolkningsökning i världen än tidigare prognoser. Men en miljard människor till är fortfarande långt över vad jorden klarar. Befolkningstrenden måste snarare vända neråt, och det kräver åtgärder för att stärka kvinnors rättigheter världen över.
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| 5. |
- Andreou, Dimitrios, et al.
(författare)
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Associations between a locus downstream DRD1 gene and cerebrospinal fluid dopamine metabolite concentrations in psychosis
- 2016
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 619, s. 126-130
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Tidskriftsartikel (refereegranskat)abstract
- Dopamine activity, mediated by the catecholaminergic neurotransmitter dopamine, is prominent in the human brain and has been implicated in schizophrenia. Dopamine targets five different receptors and is then degraded to its major metabolite homovanillic acid (HVA). We hypothesized that genes encoding dopamine receptors may be associated with cerebrospinal fluid (CSF) HVA concentrations in patients with psychotic disorder. We searched for association between 67 single nucleotide polymorphisms (SNPs) in the five dopamine receptor genes i.e., DRD1, DRD2, DRD3, DRD4 and DRD5, and the CSF HVA concentrations in 74 patients with psychotic disorder. Nominally associated SNPs were also tested in 111 healthy controls. We identified a locus, located downstream DRD1 gene, where four SNPs, rs11747728, rs11742274, rs265974 and rs11747886, showed association with CSF HVA concentrations in psychotic patients. The associations between rs11747728, which is a regulatory region variant, and rs11742274 with HVA remained significant after correction for multiple testing. These associations were restricted to psychotic patients and were absent in healthy controls. The results suggest that the DRD1 gene is implicated in the pathophysiology of psychosis and support the dopamine hypothesis of schizophrenia.
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| 6. |
- Andreou, Dimitrios, et al.
(författare)
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Cerebrospinal fluid monoamine metabolite concentrations as intermediate phenotypes between glutamate-related genes and psychosis
- 2015
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0165-1781 .- 1872-7123. ; 229:1-2, s. 497-504
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Tidskriftsartikel (refereegranskat)abstract
- Glutamate-related genes have been associated with schizophrenia, but the results have been ambiguous and difficult to replicate. Homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) are the major degradation products of the monoamines dopamine, serotonin and noradrenaline, respectively, and their concentrations in the cerebrospinal fluid (CSF), mainly HVA, have been associated with schizophrenia. In the present study, we hypothesized that CSF HVA, 5-HIAA and MHPG concentrations represent intermediate phenotypes in the association between glutamate-related genes and psychosis. To test this hypothesis, we searched for association between 238 single nucleotide polymorphisms (SNPs) in ten genes shown to be directly or indirectly implicated in glutamate transmission and CSF HVA, 5-HIAA and MHPG concentrations in 74 patients with psychotic disease. Thirty-eight nominally significant associations were found. Further analyses in 111 healthy controls showed that 87% of the nominal associations were restricted to the patients with psychosis. Some of the psychosis-only-associated SNPs found in the D-amino acid oxidase activator (DADA) and the kynurenine 3-monooxygenase (KMO) genes have previously been reported to be associated with schizophrenia. The present results suggest that CSF monoamine metabolite concentrations may represent intermediate phenotypes in the association between glutamate-related genes and psychosis.
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| 7. |
- Eklund, Johan, 1991, et al.
(författare)
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Field exposure of FeCrAl model alloys in a waste-fired boiler at 600°C: The influence of Cr and Si on the corrosion behaviour
- 2019
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Ingår i: Materials and Corrosion. - : Wiley. - 0947-5117 .- 1521-4176. ; 70:8, s. 1476-1485
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Tidskriftsartikel (refereegranskat)abstract
- Materials and Corrosion WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The aim of this study was to examine the performance of FeCrAl model alloys in a waste-fired boiler and investigate the influence of chromium and silicon content on the corrosion behaviour. The investigation was executed by utilising an air-cooled probe, giving a material temperature of 600°C throughout a 672 hr exposure. The material loss measurements were performed by utilizing an ultrasonic thickness gauge in combination with scanning electron microscopy analysis. It was found that increasing the chromium content significantly reduced the overall material loss of the FeCrAl model alloys but further accelerated the corrosion attack on the windward side. Simultaneously, the increased chromium content caused embrittlement of the material. Minor additions of silicon drastically reduced the material loss of the FeCrAl model alloys, whereas the sample ring with no silicon present was completely deteriorated. The trends observed in this field study correlated well with what has been observed in previous laboratory studies. A state-of-the-art alloy in the present environment, Inconel 625, was simultaneously exposed and showed similar performance to the silicon-containing FeCrAl model alloys with ≥10 wt% Cr.
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| 8. |
- Eklund, Johan, 1991, et al.
(författare)
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The influence of silicon on the corrosion properties of FeCrAl model alloys in oxidizing environments at 600 °C
- 2018
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X. ; 144, s. 266-276
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigates the influence of Si on the high temperature corrosion behaviour of FeCrAl model alloys in O2, O2+H2O and O2+H2O + KCl at 600 °C for up to 168 h. The investigation by SEM/EDX showed that all alloys displayed a protective behaviour in dry O2. In the more corrosive environments (O2+H2O and O2+H2O + KCl) the addition of Si affected the oxidation properties in two ways; Alloys containing Si resisted breakaway oxidation caused by Cr-evaporation (O2+H2O) and the thickness of the oxide formed after breakaway oxidation decreased with increasing amount of Si (O2+H2O + KCl).
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| 9. |
- Engelborghs, Sebastiaan, et al.
(författare)
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Consensus guidelines for lumbar puncture in patients with neurological diseases
- 2017
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Ingår i: Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. - : Wiley. - 2352-8729. ; 8, s. 111-126
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Cerebrospinal fluid collection by lumbar puncture (LP) is performed in the diagnostic workup of several neurological brain diseases. Reluctance to perform the procedure is among others due to a lack of standards and guidelines to minimize the risk of complications, such as post-LP headache or back pain. Methods We provide consensus guidelines for the LP procedure to minimize the risk of complications. The recommendations are based on (1) data from a large multicenter LP feasibility study (evidence level II-2), (2) systematic literature review on LP needle characteristics and post-LP complications (evidence level II-2), (3) discussion of best practice within the Joint Programme Neurodegenerative Disease Research Biomarkers for Alzheimer's disease and Parkinson's Disease and Biomarkers for Multiple Sclerosis consortia (evidence level III). Results Our consensus guidelines address contraindications, as well as patient-related and procedure-related risk factors that can influence the development of post-LP complications. Discussion When an LP is performed correctly, the procedure is well tolerated and accepted with a low complication rate.
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| 10. |
- Genberg, Johan, et al.
(författare)
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Source apportionment of carbonaceous aerosol in southern Sweden
- 2011
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 11:22, s. 11387-11400
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Tidskriftsartikel (refereegranskat)abstract
- A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C) and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (80%), which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (32%) and fossil fuel combustion (28%) were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP MSC-W chemical transport model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 2.2 compared to the measurements.
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| 11. |
- Golub, Malgorzata, et al.
(författare)
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Diel, seasonal, and inter-annual variation in carbon dioxide effluxes from lakes and reservoirs
- 2023
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 18:3
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Tidskriftsartikel (refereegranskat)abstract
- Accounting for temporal changes in carbon dioxide (CO2) effluxes from freshwaters remains a challenge for global and regional carbon budgets. Here, we synthesize 171 site-months of flux measurements of CO2 based on the eddy covariance method from 13 lakes and reservoirs in the Northern Hemisphere, and quantify dynamics at multiple temporal scales. We found pronounced sub-annual variability in CO2 flux at all sites. By accounting for diel variation, only 11% of site-months were net daily sinks of CO2. Annual CO2 emissions had an average of 25% (range 3%-58%) interannual variation. Similar to studies on streams, nighttime emissions regularly exceeded daytime emissions. Biophysical regulations of CO2 flux variability were delineated through mutual information analysis. Sample analysis of CO2 fluxes indicate the importance of continuous measurements. Better characterization of short- and long-term variability is necessary to understand and improve detection of temporal changes of CO2 fluxes in response to natural and anthropogenic drivers. Our results indicate that existing global lake carbon budgets relying primarily on daytime measurements yield underestimates of net emissions.
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| 12. |
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| 13. |
- Grip, Carl Erik, et al.
(författare)
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Numerical prediction and experimental verification of thermal stratification during holding in pilot plant and production ladles
- 1999
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 39:7, s. 715-721
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Tidskriftsartikel (refereegranskat)abstract
- A 3-dimensional CFD-model has been developed to simulate the natural convection flow in ladles. Qualified measurements of temperature and velocities in 107 and 7 tonne ladles have been made to verify the model. The downward convection flow at the ladle wall has been studied using radioactive isotopes and the thermal stratification has been studied by means of continuous temperature measurements. The experimental techniques are complex and additional numerical simulations have been carried out to study the effect of the measurement technique on the measurement error. The result indicates that the measurements are of sufficient accuracy for the validation. The measurements are compared to predictions from the numerical model. The main conclusion is that the theoretical CFD model gives a very accurate estimation of the temperature distribution during holding.
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| 14. |
- Grip, Carl-Erik, et al.
(författare)
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Theoretical and practical study of thermal stratification and drainage in ladles of different geometry
- 2000
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Ingår i: Scandinavian journal of metallurgy. - : Wiley. - 0371-0459 .- 1600-0692. ; 29:1, s. 30-38
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Tidskriftsartikel (refereegranskat)abstract
- SSAB Lulea, SSAB Oxelosund, MEFOS and Lulea University of Technology have cooperated in developing theoretical models for prediction of thermal stratification and drainage in steel ladles. Predicted results have been verified by measurements done in production ladles with heat weighs of 105 and 200 tonne as well as in a 7-tonne pilot plant ladle. The thermal stratification was measured by thermocouples at different depths. The drainage flow was studied by means of tracer experiments. Numerical simulation models of the steel flow were developed for 7, 105 and 200 tonne steel ladles. The agreement between predictions and measurements was found to be good. The conclusion is that CFD simulation gives a good prediction of stratification and drainage flows in production ladles.
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| 15. |
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| 16. |
- Göteson, Andreas, 1991, et al.
(författare)
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Cerebrospinal fluid proteomics targeted for central nervous system processes in bipolar disorder
- 2021
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 26, s. 7446-53
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Tidskriftsartikel (refereegranskat)abstract
- The etiopathology of bipolar disorder is largely unknown. We collected cerebrospinal fluid (CSF) samples from two independent case-control cohorts (total n = 351) to identify proteins associated with bipolar disorder. A panel of 92 proteins targeted towards central nervous system processes identified two proteins that replicated across the cohorts: the CSF concentrations of testican-1 were lower, and the CSF concentrations of C-type lectin domain family 1 member B (CLEC1B) were higher, in cases than controls. In a restricted subgroup analysis, we compared only bipolar type 1 with controls and identified two additional proteins that replicated in both cohorts: draxin and tumor necrosis factor receptor superfamily member 21 (TNFRSF21), both lower in cases than controls. This analysis additionally revealed several proteins significantly associated with bipolar type 1 in one cohort, falling just short of replicated statistical significance in the other (tenascin-R, disintegrin and metalloproteinase domain-containing protein 23, cell adhesion molecule 3, RGM domain family member B, plexin-B1, and brorin). Next, we conducted genome-wide association analyses of the case-control-associated proteins. In these analyses, we found associations with the voltage-gated calcium channel subunit CACNG4, and the lipid-droplet-associated gene PLIN5 with CSF concentrations of TNFRSF21 and CLEC1B, respectively. The reported proteins are involved in neuronal cell-cell and cell-matrix interactions, particularly in the developing brain, and in pathways of importance for lithium's mechanism of action. In summary, we report four novel CSF protein associations with bipolar disorder that replicated in two independent case-control cohorts, shedding new light on the central nervous system processes implicated in bipolar disorder.
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| 17. |
- Haukvik, Unn Kristin, et al.
(författare)
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No effect of obstetric complications on basal ganglia volumes in schizophrenia
- 2010
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Ingår i: Progress in Neuro-Psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846 .- 1878-4216. ; 34:4, s. 619-623
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Forskningsöversikt (refereegranskat)abstract
- Background: Heterogeneous findings have been reported in studies of basal ganglia volumes in schizophrenia patients as compared to healthy controls. The basal ganglia contain dopamine receptors that are known to be involved in schizophrenia pathology and to be vulnerable to pre- and perinatal hypoxic insults. Altered volumes of other brain structures (e.g. hippocampus and lateral ventricles) have been reported in schizophrenia patients with a history of obstetric complications (005). This is the first study to explore if there is a relationship between OCs and basal ganglia volume in schizophrenia. Methods: Thorough clinical investigation (including information on medication) of 54 schizophrenia patients and 54 healthy control subjects was undertaken. MR images were obtained on a 1.5T scanner, and volumes of nucleus caudatus, globus pallidum, putamen, and nucleus accumbens were quantified automatically. Information on OCs was blindly collected from original birth records. Results: Unadjusted estimates demonstrated a relationship between increasing number of OCs and larger volume of nucleus accumbens in schizophrenia patients and healthy controls. No statistically significant relationships were found between OCs and the basal ganglia volumes when controlled for intracranial volume, age, and multiple comparisons. There were no effects of typical versus atypical medication on the basal ganglia volumes. The patients with schizophrenia had larger globus pallidum volumes as compared to healthy controls, but there were no case-control differences for accumbens, putamen, or caudate volumes. Conclusion: The present results do not support the hypothesis that OCs are related to alterations in basal ganglia volume in chronic schizophrenia. (C) 2010 Elsevier Inc. All rights reserved.
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| 18. |
- Jonsson, Lina, 1982, et al.
(författare)
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Association of Occupational Dysfunction and Hospital Admissions With Different Polygenic Profiles in Bipolar Disorder.
- 2024
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Ingår i: The American journal of geriatric psychiatry. - 1064-7481. ; 181:7, s. 620-629
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Tidskriftsartikel (refereegranskat)abstract
- Many but not all persons with bipolar disorder require hospital care because of severe mood episodes. Likewise, some but not all patients experience long-term occupational dysfunction that extends beyond acute mood episodes. It is not known whether these dissimilar outcomes of bipolar disorder are driven by different polygenic profiles. Here, polygenic scores (PGSs) for major psychiatric disorders and educational attainment were assessed for associations with occupational functioning and psychiatric hospital admissions in bipolar disorder.A total of 4,782 patients with bipolar disorder and 2,963 control subjects were genotyped and linked to Swedish national registers. Longitudinal measures from at least 10 years of registry data were used to derive percentage of years without employment, percentage of years with long-term sick leave, and mean number of psychiatric hospital admissions per year. Ordinal regression was used to test associations between outcomes and PGSs for bipolar disorder, schizophrenia, major depressive disorder, attention deficit hyperactivity disorder (ADHD), and educational attainment. Replication analyses of hospital admissions were conducted with data from the Bipolar Disorder Research Network cohort (N=4,219).Long-term sick leave and unemployment in bipolar disorder were significantly associated with PGSs for schizophrenia, ADHD, major depressive disorder, and educational attainment, but not with the PGS for bipolar disorder. By contrast, the number of hospital admissions per year was associated with higher PGSs for bipolar disorder and schizophrenia, but not with the other PGSs.Bipolar disorder severity (indexed by hospital admissions) was associated with a different polygenic profile than long-term occupational dysfunction. These findings have clinical implications, suggesting that mitigating occupational dysfunction requires interventions other than those deployed to prevent mood episodes.
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| 19. |
- Jonsson, Sofi, et al.
(författare)
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Differentiated availability of geochemical mercury pools controls methylmercury levels in estuarine sediment and biota
- 2014
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5, s. 4624-
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Tidskriftsartikel (refereegranskat)abstract
- Neurotoxic methylmercury (MeHg) formed from inorganic divalent mercury (HgII) accumulates in aquatic biota and remains at high levels worldwide. It is poorly understood to what extent different geochemical Hg pools contribute to these levels. Here we report quantitative data on MeHg formation and bioaccumulation, in mesocosm water-sediment model ecosystems, using five HgII and MeHg isotope tracers simulating recent Hg inputs to the water phase and Hg stored in sediment as bound to natural organic matter or as metacinnabar. Calculations for an estuarine ecosystem suggest that the chemical speciation of HgII solid/adsorbed phases control the sediment Hg pool's contribution to MeHg, but that input of MeHg from terrestrial and atmospheric sources bioaccumulates to a substantially greater extent than MeHg formed in situ in sediment. Our findings emphasize the importance of MeHg loadings from catchment runoff to MeHg content in estuarine biota and we suggest that this contribution has been underestimated.
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| 20. |
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| 21. |
- Jonsson, Sofi, 1984-, et al.
(författare)
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Geochemical and Dietary Drivers of Mercury Bioaccumulation in Estuarine Benthic Invertebrates
- 2022
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:14, s. 10141-10148
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Tidskriftsartikel (refereegranskat)abstract
- Sediments represent the main reservoir of mercury (Hg) in aquatic environments and may act as a source of Hg to aquatic food webs. Yet, accumulation routes of Hg from the sediment to benthic organisms are poorly constrained. We studied the bioaccumulation of inorganic and methylmercury (HgII and MeHg, respectively) from different geochemical pools of Hg into four groups of benthic invertebrates (amphipods, polychaetes, chironomids, and bivalves). The study was conducted using mesocosm experiments entailing the use of multiple isotopically enriched Hg tracers and simulation of estuarine systems with brackish water and sediment. We applied different loading regimes of nutrients and terrestrial organic matter and showed that the vertical localization and the chemical speciation of HgII and MeHg in the sediment, in combination with the diet composition of the invertebrates, consistently controlled the bioaccumulation of HgII and MeHg into the benthic organisms. Our results suggest a direct link between the concentration of MeHg in the pelagic planktonic food web and the concentration of MeHg in benthic amphipods and, to some extent, in bivalves. In contrast, the quantity of MeHg in benthic chironomids and polychaetes seems to be driven by MeHg accumulation via the benthic food web. Accounting for these geochemical and dietary drivers of Hg bioaccumulation in benthic invertebrates will be important to understand and predict Hg transfer between the benthic and the pelagic food web, under current and future environmental scenarios.
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| 22. |
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| 23. |
- Jonsson, Sofi, 1984-, et al.
(författare)
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Mercury methylation rates for geochemically relevant HgII species in sediments
- 2012
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:21, s. 11653-11659
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Tidskriftsartikel (refereegranskat)abstract
- Monomethylmercury (MeHg) in fish from freshwater, estuarine and marine environments are a major global environmental issue. Mercury levels in biota are mainly controlled by the methylation of inorganic mercuric mercury (HgII) to MeHg in water, sediments and soils. There is, however, a knowledge gap concerning the mechanisms and rates of methylation of specific geochemical HgII species. Such information is crucial for a better understanding of variations in MeHg concentrations among ecosystems and, in particular, for predicting the outcome of currently proposed measures to mitigate mercury emissions and reduce MeHg concentrations in fish. To fill this knowledge gap we propose an experimental approach using HgII isotope tracers, with defined and geochemically important adsorbed and solid HgII forms in sediments, to study MeHg formation. We report HgII methylation rate constants, km, in estuarine sediments which span over two orders of magnitude depending on chemical form of added tracer: metacinnabar (β-201HgS(s)) < cinnabar (α-199HgS(s)) < HgII reacted with mackinawite (≡FeS-202HgII) < HgII bonded to natural organic matter (NOM-196HgII) < a typical aqueous tracer (198Hg(NO3)2(aq)). We conclude that a combination of thermodynamic and kinetic effects of HgII solid-phase dissolution and surface desorption control the HgII methylation rate in sediments and causes the large observed differences in km-values. The selection of relevant solid-phase and surface adsorbed HgII tracers will therefore be crucial to achieving biogeochemically accurate estimates of ambient HgII methylation rates.
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| 24. |
- Jonsson, Sofi, et al.
(författare)
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Terrestrial discharges mediate trophic shifts and enhance methylmercury accumulation in estuarine biota
- 2017
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Ingår i: Science Advances. - : American association for the advancement of science. - 2375-2548. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- The input of mercury (Hg) to ecosystems is estimated to have increased two- to fivefold during the industrial era, and Hg accumulates in aquatic biota as neurotoxic methylmercury (MeHg). Escalating anthropogenic land use and climate change are expected to alter the input rates of terrestrial natural organic matter (NOM) and nutrients to aquatic ecosystems. For example, climate change has been projected to induce 10 to 50% runoff increases for large coastal regions globally. A major knowledge gap is the potential effects on MeHg exposure to biota following these ecosystem changes. We monitored the fate of five enriched Hg isotope tracers added to mesocosm scale estuarine model ecosystems subjected to varying loading rates of nutrients and terrestrial NOM. We demonstrate that increased terrestrial NOM input to the pelagic zone can enhance the MeHg bioaccumulation factor in zooplankton by a factor of 2 to 7 by inducing a shift in the pelagic food web from autotrophic to heterotrophic. The terrestrial NOM input also enhanced the retention of MeHg in the water column by up to a factor of 2, resulting in further increased MeHg exposure to pelagic biota. Using mercury mass balance calculations, we predict that MeHg concentration in zooplankton can increase by a factor of 3 to 6 in coastal areas following scenarios with 15 to 30% increased terrestrial runoff. The results demonstrate the importance of incorporating the impact of climate-induced changes in food web structure on MeHg bioaccumulation in future biogeochemical cycling models and risk assessments of Hg.
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| 25. |
- Jonsson, Sofi, 1984-
(författare)
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Unraveling the importance of solid and adsorbed phase mercury speciation for methylmercury formation, evasion and bioaccumulation
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Monomethylmercury, MeHg, is formed under anoxic conditions in waters, sediments and soils and then bioaccumulated and biomagnified in aquatic food webs, negatively effecting both human and wildlife health. It is generally accepted that precipitation of mercury, Hg, and adsorption of Hg to e.g. organic matter and mineral surfaces are important processes limiting the reactivity of Hg mobilized in the environment by natural and anthropogenic activities. However, knowledge concerning the role of different solid and adsorbed chemical forms of Hg for MeHg formation, evasion and bioaccumulation is missing. Such information is vital for the understanding of environmental processes controlling MeHg formation and bioaccumulation, as well as for predicting how changes in e.g. loading rates of atmospheric Hg and the outcome of climate change scenarios and anthropogenic land use could alter Hg concentrations in biota.In this thesis, a novel experimental approach, using isotopically enriched solid and adsorbed phases of inorganic Hg, HgII, as tracers, was developed. Using this approach, we successfully determined rates of MeHg formation from solid and adsorbed Hg species in sediment slurries and in mesocosm systems under conditions closely resembling those in field. We conclude that the solid/adsorbed phase speciation of HgII is a major controlling factor for MeHg net formation rates. Microcosm experiments revealed that newly formed MeHg was a major contributor to the evasion of MeHg from the water‒sediment system, emphasizing the importance of MeHg formation rate, rather than MeHg concentration, in the sediment for this process. From mesocosm systems, we provide experimental evidence, as well as quantitate data, for that terrestrial and atmospheric sources of HgII and MeHg are more available for methylation and bioaccumulation processes than HgII and MeHg stored and formed in sediments. This suggests that the contribution from terrestrial and atmospheric sources to the accumulation of Hg in fish may have been underestimated. As a consequence, in regions where climate change is expected to further increase land runoff, terrestrial MeHg sources may have even higher negative effects on biota than previously thought. Data and concepts presented in this thesis lay the basis for unprecedented in-depth modeling of processes in the Hg biogeochemical cycle that will improve our understanding and the predicting power on how aquatic ecosystems may respond to environmental changes or differences in loading rates for atmospheric Hg.
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| 26. |
- Karlsson, Sofia, 1982, et al.
(författare)
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A Laboratory Study of the in Situ Sulfation of Alkali Chloride Rich Deposits: Corrosion Perspective
- 2016
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 30:9, s. 7256-7267
-
Tidskriftsartikel (refereegranskat)abstract
- The initial corrosive effect of small (1.35 mu mol/cm(2)) and large (13.5 mu mol/cm(2)) amounts of KCl on 304L has been investigated. The investigations were performed in both the absence and presence of 300 ppm of SO2 at 600 degrees C. The results showed that in the absence of SO2 KCl accelerates the rate of corrosion by means of two types of corrosion attack: a general attack and a steel grain boundary attack. The general attack has been proved to be initiated by K2CrO4 formation. Meanwhile, the steel grain boundary attack is suggested to be accelerated by HCl released due to the chromate formation which increased with higher amounts of KCl. The presence of KCl and SO2 resulted in the simultaneous formation of K2SO4 and K2CrO4. The chromate formation resulted in a general corrosion attack. However, the oxide growth was significantly reduced due to the very fast sulfation reaction. In contrast, the steel grain boundary attack increased in the presence of SO2. It is suggested that the attack is accelerated by HCl released from the sulfation reaction and by sulfidation of the steel grain boundaries.
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| 27. |
- Larsson, Erik, 1983, et al.
(författare)
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A Comparative Study of the Initial Corrosion of KCl and PbCl2 on a Low-Alloyed Steel
- 2017
-
Ingår i: Oxidation of Metals. - : Springer Science and Business Media LLC. - 1573-4889 .- 0030-770X. ; 87:5-6, s. 779-787
-
Tidskriftsartikel (refereegranskat)abstract
- Heat exchange surfaces in biomass- and waste-fired boilers are exposed to corrosive species due to the considerable amounts of alkali chlorides and PbCl2 which are released during combustion. The corrosivity of alkali chlorides toward superheater alloys exposed at high temperature has been studied extensively. However, at lower material temperatures, i.e., at waterwall conditions, considerably less research has been performed. In order to investigate the effect of small amounts of KCl and PbCl2 during the initial stages of the corrosion attack, a Fe–2.25Cr–1Mo steel was exposed for 24 h in an atmospheres consisting of O2 + H2O + N2 at 400 °C. Both KCl and PbCl2 resulted in an increased corrosion rate compared to the reference. The aim of the present paper is to investigate the influence of KCl and PbCl2 on the initial oxidation of a Fe–2.25Cr–1Mo steel. The work involves a detailed microstructural investigation as well as thermodynamic equilibrium calculations.
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| 28. |
- Larsson, Erik, 1983, et al.
(författare)
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The Influence of KCl and HCl on the High-Temperature Oxidation of a Fe-2.25Cr-1Mo Steel at 400 °C
- 2020
-
Ingår i: Oxidation of Metals. - : Springer Science and Business Media LLC. - 1573-4889 .- 0030-770X. ; 93:1-2, s. 29-52
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of alkali- and chlorine-containing compounds on the corrosion of superheater alloys has been studied extensively. The current paper instead investigates the corrosive effects of KCl and HCl under conditions relevant to waterwall conditions. A low-alloy (Fe-2.25Cr-1Mo) steel was exposed to KCl(s), 500 vppm HCl(g) and (KCl + HCl) in the presence of 5%O2 and 20% H2O at 400 °C. The results indicate that alloy chlorination by KCl occurs by an electrochemical process, involving cathodic formation of chemisorbed KOH on the scale surface and anodic formation of solid FeCl2 at the bottom of the scale. The process is accompanied by extensive cracking and delamination of the iron oxide scale, resulting in a complex, convoluted scale morphology. Adding 500 vppm HCl to the experimental environment (KCl + HCl) initially greatly accelerated the formation of FeCl2 at the scale/alloy interface. The accelerated alloy chlorination is attributed to HCl reacting with KOH at the scale surface, causing the cathodic process to be depolarized. A rapid slowing down of the rate of chlorination and corrosion in KCl + HCl environment was observed which was attributed to the electronically insulating nature of the FeCl2 layer which forms at the bottom of the scale, disconnecting the anodic and cathodic regions.
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| 29. |
- Liem-Nguyen, Van, et al.
(författare)
-
Effects of Nutrient Loading and Mercury Chemical Speciation on the Formation and Degradation of Methylmercury in Estuarine Sediment
- 2016
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:13, s. 6983-6990
-
Tidskriftsartikel (refereegranskat)abstract
- Net formation of methylmercury (MeHg) in sediments is known to be affected by the availability of inorganic divalent mercury (HgII) and by the activities of HgII methylating and MeHg demethylating bacteria. Enhanced autochthonous organic matter deposition to the benthic zone, following increased loading of nutrients to the pelagic zone, has been suggested to increase the activity of HgII methylating bacteria and thus the rate of net methylation. However, the impact of increased nutrient loading on the biogeochemistry of mercury (Hg) is challenging to predict as different geochemical pools of Hg may respond differently to enhanced bacterial activities. Here, we investigate the combined effects of nutrient (N and P) supply to the pelagic zone and the chemical speciation of HgII and of MeHg on MeHg formation and degradation in a brackish sediment-water mesocosm model ecosystem. By use of Hg isotope tracers added in situ to the mesocosms or ex situ in incubation experiments, we show that the MeHg formation rate increased with nutrient loading only for HgII tracers with a high availability for methylation. Tracers with low availability did not respond significantly to nutrient loading. Thus, both microbial activity (stimulated indirectly through plankton biomass production by nutrient loading) and HgII chemical speciation were found to control the MeHg formation rate in marine sediments.
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| 30. |
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| 31. |
- Moberg, Christina, et al.
(författare)
-
De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 32. |
- Najar, Hemen, et al.
(författare)
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Recent Secular Trends of Body Mass Index in Individuals With Bipolar Disorders and in the General Population.
- 2024
-
Ingår i: The American journal of psychiatry. - 1535-7228. ; 181:1, s. 39-46
-
Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to investigate secular trends and distribution of body mass index (BMI) among individuals with bipolar disorders and the general population between 2008 and 2019.Data were from the Swedish National Quality Register for Bipolar Disorder, where 24,423 adults with bipolar disorders were identified, and from the national Swedish Living Conditions Surveys, where 77,485 adults from the general population were identified. Quantile regression was used to compare the 15th, 50th, and 85th percentiles of BMI across age and study years.The study sample included 22,127 individuals with bipolar disorders (mean age, 48 years; 63% women) and 71,894 individuals from the general population (mean age, 52 years; 51% women). BMI percentiles were higher among individuals with bipolar disorders. At the 50th percentile, the BMI group differences were 1.1 (95% CI=0.8-1.14) for men and 1.8 (95% CI=1.5-2.1) for women. The gap was widest at the 85th BMI percentile: men, 2.3 (95% CI=1.8-2.8); women, 4.1 (95% CI=3.7-4.6). BMI increased over time in both study groups, but more in the group with bipolar disorders. The changes per decade in mean BMI were 0.4 (95% CI=0.3-0.5) among men in the general population, 1.1 (95% CI=0.7-1.4) among men with bipolar disorders, 0.6 (95% CI=0.5-0.7) among women in the general population, and 1.4 (95% CI=1.1-1.7) among women with bipolar disorders. Women with bipolar disorders had the highest prevalence and the greatest rate of increase of obesity. In 2019, the obesity prevalence was 33% among women and 29% among men with bipolar disorders, compared with 13% and 15%, respectively, among women and men in the general population.Adults with bipolar disorders had a higher BMI and a higher prevalence of obesity than the general population, indicating a higher cardiometabolic risk. Annually, BMI increased more in the group with bipolar disorders than in the general population, particularly among women and among those with high BMI.
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| 33. |
- Wennström, Lovisa, et al.
(författare)
-
Acute Myeloid Leukemia in Adolescents and Young Adults Treated in Pediatric and Adult Departments in the Nordic Countries
- 2016
-
Ingår i: Pediatric Blood & Cancer. - : Wiley-Blackwell. - 1545-5009 .- 1545-5017. ; 63:1, s. 83-92
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Studies on adolescents and young adults with acute lymphoblastic leukemia suggest better results when using pediatric protocols for adult patients, while corresponding data for acute myeloid leukemia (AML) are limited. Procedure: We investigated disease characteristics and outcome for de novo AML patients 10-30 years old treated in pediatric or adult departments. We included 166 patients 10-18 years of age with AML treated according to the pediatric NOPHO-protocols (1993-2009) compared with 253 patients aged 15-30 years treated in hematology departments (1996-2009) in the Nordic countries. Results: The incidence of AML was 4.9/million/year for the age group 10-14 years, 6.5 for 15-18 years, and 6.9 for 19-30 years. Acute promyelocytic leukemia (APL) was more frequent in adults and in females of all ages. Pediatric patients with APL had similar overall survival as pediatric patients without APL. Overall survival at 5 years was 60% (52-68%) for pediatric patients compared to 65% (58-70%) for adult patients. Cytogenetics and presenting white blood cell count were the only independent prognostic factors for overall survival. Age was not an independent prognostic factor. Conclusions: No difference was found in outcome for AML patients age 10-30 years treated according to pediatric as compared to adult protocols.
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| 34. |
- Zackrisson, Erik, et al.
(författare)
-
Hunting for dark halo substructure using submilliarcsecond-scale observations of macrolensed radio jets
- 2013
-
Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 431:3, s. 2172-2183
-
Tidskriftsartikel (refereegranskat)abstract
- Dark halo substructure may reveal itself through secondary, small-scale gravitational lensing effects on light sources that are macrolensed by a foreground galaxy. Here, we explore the prospects of using Very Long Baseline Interferometry (VLBI) observations of multiply-imaged quasar jets to search for submilliarcsecond-scale image distortions produced by various forms of dark substructures in the 10(3)-10(8) M-circle dot mass range. We present lensing simulations relevant for the angular resolutions attainable with the existing European VLBI Network, the global VLBI array and an upcoming observing mode in which the Atacama Large Millimeter Array (ALMA) is connected to the global VLBI array. While observations of this type would not be sensitive to standard cold dark matter subhaloes, they can be used to detect the more compact forms of halo substructure predicted in alternative structure formation scenarios. By mapping approximately five strongly lensed systems, it should be possible to detect or robustly rule out primordial black holes in the 10(3)-10(6) M-circle dot mass range if they constitute greater than or similar to 1 per cent of the dark matter in these lenses. Ultracompact minihaloes are harder to detect using this technique, but 10(6)-10(8) M-circle dot ultracompact minihaloes could in principle be detected if they constitute greater than or similar to 10 per cent of the dark matter.
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| 35. |
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| 36. |
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| 37. |
- Abdallah, J., et al.
(författare)
-
A study of b(b)over-bar production in e(+)e(-) collisions at root s=130-207 GeV
- 2009
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 60:1, s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements are presented of R-b, the ratio of the b (b) over bar cross-section to the q (q) over bar cross-section in e(+)e(-) collisions, and the forward-backward asymmetry A(FB)(b) at twelve energy points in the range root s = 130-207 GeV. These results are found to be consistent with the Standard Model expectations. The measurements are used to set limits on new physics scenarios involving contact interactions.
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| 38. |
- Abdallah, J., et al.
(författare)
-
A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z Pole
- 2011
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:2, s. 1557-
-
Tidskriftsartikel (refereegranskat)abstract
- The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP. Two complementary methods are used to reconstruct the energy of weakly decaying b-hadrons, E-B(weak). The average value of x(B)(weak) = E-B(weak)/E-beam is measured to be 0.699 +/- 0.011. The resulting x(B)(weak) distribution is then analysed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract measurements of the non-perturbative contribution to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data: a = 1.84(-0.21)(+0.23) and b = 0.642(-0.063)(+0.073) GeV-2, with a correlation factor rho = 92.2%. Combining the data on the b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of x(B)(weak) is found to be 0.7092 +/- 0.0025 and the non-perturbative fragmentation component is extracted. Using the combined distribution, a better determination of the Lund parameters is also obtained: a = 1.48(-0.10)(+0.11) and b = 0.509(-0.023)(+0.024) GeV-2, with a correlation factor rho = 92.6%.
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| 39. |
- Abdallah, J, et al.
(författare)
-
Correlations between polarisation states of W particles in the reaction e(-)e(+)-> W-W+ at LEP2 energies 189-209 GeV
- 2009
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 63:4, s. 611-623
-
Tidskriftsartikel (refereegranskat)abstract
- In a study of the reaction e(-)e(+)-> W-W+ with the DELPHI detector, the probabilities of the two W particles occurring in the joint polarisation states transverse-transverse (T T), longitudinal-transverse plus transverse-longitudinal (LT) and longitudinal-longitudinal (LL) have been determined using the final states WW -> lvq (q) over bar (l = e, mu). The two-particle joint polarisation probabilities, i.e. the spin density matrix elements rho T T, rho LT, rho LL, are measured as functions of the W- production angle, theta(W-), at an average reaction energy of 198.2 GeV. Averaged over all cos.W-, the following joint probabilities are obtained: (rho) over barT T = (67 +/- 8)%, (rho) over barL T = (30 +/- 8)%, (rho) over barL T = (3 +/- 7)%. These results are in agreement with the Standard Model predictions of 63.0%, 28.9% and 8.1%, respectively. The related polarisation cross-sections sigma(TT), sigma(LT) and sigma(LL) are also presented.
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| 40. |
- Abdallah, J, et al.
(författare)
-
Inclusive single-particle production in two-photon collisions at LEP II with the DELPHI detector
- 2009
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 678:5, s. 444-449
-
Tidskriftsartikel (refereegranskat)abstract
- A study of the inclusive charged hadron production in two-photon collisions is described. The data were collected with the DELPHI detector at LEP II. Results on the inclusive single-particle p(T) distribution and the differential charged hadrons d sigma/dp(T) cross-section are presented and compared to the predictions of perturbative NLO QCD calculations and to published results. (C) 2009 Elsevier B.V. All rights reserved.
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| 41. |
- Abdallah, J., et al.
(författare)
-
Measurement of the electron structure function F-2(e) at LEP energies
- 2014
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 737, s. 39-47
-
Tidskriftsartikel (refereegranskat)abstract
- The hadronic part of the electron structure function F-2(e) has been measured for the first time, using e(+)e(-) data collected by the DELPHI experiment at LEP, at centre-of-mass energies of root s = 91.2-209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F-2(e) data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F-2(gamma) analyses and help in refining existing parameterisations.
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| 42. |
- Abdallah, J., et al.
(författare)
-
Measurements of CP-conserving trilinear gauge boson couplings WWV (V gamma, Z) in e(+)e(-) collisions at LEP2
- 2010
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 66:1-2, s. 35-56
-
Tidskriftsartikel (refereegranskat)abstract
- The data taken by DELPHI at centre-of-mass energies between 189 and 209 GeV are used to place limits on the CP-conserving trilinear gauge boson couplings Delta g(1)(Z), lambda(gamma) and Delta k(gamma) associated to W+W- and single W production at LEP2. Using data from the jjl nu, jjjj, jjX and lX final states, where j,l and X represent a jet, a lepton and missing four-momentum, respectively, the following limits are set on the couplings when one parameter is allowed to vary and the others are set to their Standard Model values of zero: Delta g(1)(Z) =-0.025-(+0.033)(0.030,), lambda(gamma) = 0.002(-0.035)(+0.035) and Delta k(gamma) = 0.024(-0.081)(+0.077). Results are also presented when two or three parameters are allowed to vary. All observations are consistent with the predictions of the Standard Model and supersede the previous results on these gauge coupling parameters published by DELPHI.
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| 43. |
- Abdallah, J, et al.
(författare)
-
Observation of the muon inner bremsstrahlung at LEP1
- 2008
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:57, s. 499-514
-
Tidskriftsartikel (refereegranskat)abstract
- Muon bremsstrahlung photons converted in front of the DELPHI main tracker (TPC) in dimuon events at LEP1 were studied in two photon kinematic ranges: 0.2< E-gamma <= 1 GeV and transverse momentum with respect to the parent muon p(T) < 40 MeV/c, and 1< E-gamma <= 10 GeV and pT < 80 MeV/c. A good agreement of the observed photon rate with predictions from QED for the muon inner bremsstrahlung was found, contrary to the anomalous soft photon excess that has been observed recently in hadronic Z(0) decays. The obtained ratios of the observed signal to the predicted level of the muon bremsstrahlung are 1.06 +/- 0.12 +/- 0.07 in the photon energy range 0.2< E-gamma <= 1 GeV and 1.04 +/- 0.09 +/- 0.12 in the photon energy range 1< E-gamma <= 10 GeV. The bremsstrahlung dead cone is observed for the first time in the direct photon production at LEP.
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| 44. |
- Abdallah, J., et al.
(författare)
-
Search for one large extra dimension with the DELPHI detector at LEP
- 2009
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 60:1, s. 17-23
-
Tidskriftsartikel (refereegranskat)abstract
- Single photons detected by the DELPHI experiment at LEP2 in the years 1997-2000 are reanalysed to investigate the existence of a single extra dimension in a modified ADD scenario with slightly warped large extra dimensions. The data collected at centre-of-mass energies between 180 and 209 GeV for an integrated luminosity of similar to 650 pb(-1) agree with the predictions of the Standard Model and allow a limit to be set on graviton emission in one large extra dimension. The limit obtained on the fundamental mass scale M-D is 1.69 TeV/c(2) at 95% CL, with an expected limit of 1.71 TeV/c(2).
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| 45. |
- Abdallah, J., et al.
(författare)
-
Search for pentaquarks in the hadronic decays of the Z boson with the DELPHI detector at LEP
- 2007
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 653:2-4, s. 151-160
-
Tidskriftsartikel (refereegranskat)abstract
- The quark model does not exclude states composed of more than three quarks, like pentaquark systems. Controversial evidence for such states has been published in the last years, in particular: for a strange pentaquark Theta(1540)(+); for a double-strange state, the Xi(1862)(--), subsequently called Phi(1860)--; and for a charmed state, the Theta(c)(3100)(0). If confirmed, a full pentaquark family might exist; such pentaquark states could be produced in e(+)e(-) annihilations near the Z energy. In this Letter a search for pentaquarks is described using the DELPHI detector at LEP, characterized by powerful particle identification sub-systems crucial in the separation of the signal from the background for these states. At 95% CL, upper limits are set on the production rates N of such particles and their charge-conjugate state per Z decay: N-Theta+ x Br(Theta(+) -> pK(S)(0)) < 5.1 x 10(-4), N Theta++ < 1.6 x 10(-3), N Phi(1860)-- x Br((P(1860)-- -> Xi(-)pi(-)) < 2.9 x 10(-4), N-Theta c(3100)0 x Br(Theta(c)(3100)(0) -> D*(+)p) < 8.8 x 10(-4).
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| 46. |
- Abdallah, J., et al.
(författare)
-
Search for single top quark production via contact interactions at LEP2
- 2011
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:2, s. 1555-
-
Tidskriftsartikel (refereegranskat)abstract
- Single top quark production via four-fermion contact interactions associated to flavour-changing neutral currents was searched for in data taken by the DELPHI detector at LEP2. The data were accumulated at centre-of-mass energies ranging from 189 to 209 GeV, with an integrated luminosity of 598.1 pb(-1). No evidence for a signal was found. Limits on the energy scale Lambda, were set for scalar-, vector- and tensor-like coupling scenarios.
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| 47. |
- Abdallah, J., et al.
(författare)
-
Study of leading hadrons in gluon and quark fragmentation
- 2006
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 643:3-4, s. 147-157
-
Tidskriftsartikel (refereegranskat)abstract
- The study of quark jets in e(+)e(-) reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However. our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (less than or similar to 2 GeV/c(2)) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.
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| 48. |
- Abdallah, J., et al.
(författare)
-
Study of the dependence of direct soft photon production on the jet characteristics in hadronic Z (0) decays
- 2010
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 67:3-4, s. 343-366
-
Tidskriftsartikel (refereegranskat)abstract
- An analysis of the direct soft photon production rate as a function of the parent jet characteristics is presented, based on hadronic events collected by the DELPHI experiment at LEP1. The dependences of the photon rates on the jet kinematic characteristics (momentum, mass, etc.) and on the jet charged, neutral and total hadron multiplicities are reported. Up to a scale factor of about four, which characterizes the overall value of the soft photon excess, a similarity of the observed soft photon behavior to that of the inner hadronic bremsstrahlung predictions is found for the momentum, mass, and jet charged multiplicity dependences. However for the dependence of the soft photon rate on the jet neutral and total hadron multiplicities a prominent difference is found for the observed soft photon signal as compared to the expected bremsstrahlung from final state hadrons. The observed linear increase of the soft photon production rate with the jet total hadron multiplicity and its strong dependence on the jet neutral multiplicity suggest that the rate is proportional to the number of quark pairs produced in the fragmentation process, with the neutral pairs being more effectively radiating than the charged ones.
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| 49. |
- Abdallah, J., et al.
(författare)
-
Z gamma* production in e(+) e(-) interactions at root s=183-209 GeV
- 2007
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 51:3, s. 503-523
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of Z gamma* production are presented using data collected by the DELPHI detector at centre-of-mass energies ranging from 183 to 209 GeV, corresponding to an integrated luminosity of about 667 pb(-1). The measurements cover a wide range of the possible final state four-fermion configurations: hadronic and leptonic (e(+) e(-) q (q) over bar, mu(+) mu(-) q (q) over bar ,q (q) over barv (v) over bar), fully leptonic (l(+) l(-) l' (+) l'(-)) and fully hadronic. nal states (q (q) over barq (q) over bar, with a low mass q (q$) over bar pair). Measurements of the Z gamma* cross-section for the various. nal states have been compared with the Standard Model expectations and found to be consistent within the errors. In addition, a total cross-section measurement of the l(+) l(-) l'(+)l'(-) cross-section is reported, and found to be in agreement with the prediction of the Standard Model.
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| 50. |
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