| 1. |
- Aad, G., et al.
(författare)
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Studies of the performance of the ATLAS detector using cosmic-ray muons
- 2011
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:3
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Tidskriftsartikel (refereegranskat)abstract
- Muons from cosmic-ray interactions in the atmosphere provide a high-statistics source of particles that can be used to study the performance and calibration of the ATLAS detector. Cosmic-ray muons can penetrate to the cavern and deposit energy in all detector subsystems. Such events have played an important role in the commissioning of the detector since the start of the installation phase in 2005 and were particularly important for understanding the detector performance in the time prior to the arrival of the first LHC beams. Global cosmic-ray runs were undertaken in both 2008 and 2009 and these data have been used through to the early phases of collision data-taking as a tool for calibration, alignment and detector monitoring. These large datasets have also been used for detector performance studies, including investigations that rely on the combined performance of different subsystems. This paper presents the results of performance studies related to combined tracking, lepton identification and the reconstruction of jets and missing transverse energy. Results are compared to expectations based on a cosmic-ray event generator and a full simulation of the detector response.
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| 2. |
- Aad, G., et al.
(författare)
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The ATLAS Inner Detector commissioning and calibration
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 787-821
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
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| 3. |
- Aad, G., et al.
(författare)
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The ATLAS Simulation Infrastructure
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 823-874
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Tidskriftsartikel (refereegranskat)abstract
- The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.
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| 4. |
- Aad, G., et al.
(författare)
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Commissioning of the ATLAS Muon Spectrometer with cosmic rays
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 875-916
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.
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| 5. |
- Lin, Qin-Lu, et al.
(författare)
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Effect of colloidal structures on the stability of five flavonoids with different hydrophilicity
- 2008
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 22:4, s. 700-705
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Tidskriftsartikel (refereegranskat)abstract
- Autoxidation of five flavonoids representing range of different hydrophilicities (epicatechin gallate (ECG), (+) catechin((+)Q, epicatechin (EC), epigallocatechin gallate (EGCG) and epigallocatechin (EGC)) in three different aqueous solutions: molecular solution, micellar solution (Tween 20) and liposoml dispersion (soybean lecithin) was monitored by HPLC. The rate of oxidaton of the five flvonoids was higher at pH 4.5 than at pH 3.5. Compared with the control, addition of Tween-20 (micellar structure) and lecithin (liposomal structure) significantly decreased the degradation of flavonoids. In the presence of lecithin the autoxidation of all the five flavonoids was slower than in the presence of Tween-20. The effective protection of the colloidal structures was compared the hydrophilicity of the flavonoids estimated from the partitioning between octanol and water. The protection from oxidation in the presence of the colloidal structures (micellar or liposomal) increased with increasing partitioning of a flavonoid towards the hydrophobic environment. The protecting effect of the colloidal structures was more effective at pH 4.5 than at pH 3.5.
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| 6. |
- Penarrieta, Mauricio, et al.
(författare)
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Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): An Andean pseudocereal
- 2008
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Ingår i: Molecular Nutrition and Food Research. - : Wiley. - 1613-4133 .- 1613-4125. ; 52:6, s. 708-717
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Tidskriftsartikel (refereegranskat)abstract
- Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 in altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as mu mol of Trolox equivalents/g dw. The content of TPH was 12.4-71.2 mu mol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 mu mol of catechin equivalents/g dw. The data obtained by the four methods showed several significant Correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health.
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| 7. |
- Penarrieta, Mauricio, et al.
(författare)
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Total Antioxidant Capacity and Content of Phenolic Compounds in Wild Strawberries (Fragaria vesca) Collected in Bolivia
- 2009
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Ingår i: International Journal of Fruit Science. - : Informa UK Limited. - 1553-8362 .- 1553-8621. ; 9:4, s. 344-359
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Tidskriftsartikel (refereegranskat)abstract
- To study the composition of wild strawberries grown at high altitude, total antioxidant capacity, total phenolic compounds, total flavonoids, and individual phenolic compounds were measured in wild strawberries (Fragaria vesca) collected between 2,650 and 3,300 m above sea level in Bolivia. Total antioxidant capacity, as assessed by the ferric-reducing antioxidant power and 2,2¢-azinobis( 3-ethylbenzotiazoline-6-sulphonic acid) methods, was in the range 16-39 mmol of Trolox equivalents/g fw by both methods. The total phenolic content was 9.7–21 mmol gallic acid equivalents/g fw, and the flavonoid content ranged between 2.8 and 4.9 mmol of catechin equivalents/g fw. The data obtained by the four methods showed several significant linear correlations confirming that flavonoids and other phenolic compounds contributed significantly to the total antioxidant capacity values. Reversed-phase high performance liquid chromatography analysis of extracts subjected to acid hydrolysis showed the presence of seven major fractions, tentatively identified as ellagic acid, cyanidin, pelargonidin, quercetin, kaempferol, gallic acid derivatives, and catechin derivatives. The data indicated that wild strawberries have a somewhat higher total antioxidant capacity content in comparison with that reported for cultivated strawberries. No obvious difference to the composition reported for wild strawberries grown at low altitude could be found.
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| 8. |
- Samuelsson, John, 1981-, et al.
(författare)
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Autoimmune comorbidity in type 1 diabetes and its association with metabolic control and mortality risk in young people: a population-based study
- 2024
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Ingår i: Diabetologia. - : SPRINGER. - 0012-186X .- 1432-0428.
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis: This register-based study aimed to describe autoimmune comorbidity in children and young adults from type 1 diabetes onset, and to investigate whether such comorbidity was associated with a difference in HbA1c or mortality risk compared with children/young adults with type 1 diabetes without autoimmune comorbidity. Methods: A total of 15,188 individuals from the Swedish National Diabetes Register, registered with type 1 diabetes before 18 years of age between 2000 and 2019, were included. Five randomly selected control individuals from the Swedish population (Statistics Sweden) were matched to each individual with type 1 diabetes (n=74,210 [346 individuals with type 1 diabetes were not found in the Statistics Sweden register at the date of type 1 diabetes diagnosis, so could not be matched to control individuals]). The National Patient Register was used to attain ICD-10 codes on autoimmune diseases and the Cause of Death Register was used to identify deceased individuals. Results: In the total type 1 diabetes cohort, mean±SD age at onset of type 1 diabetes was 9.5±4.4 years and mean disease duration at end of follow-up was 8.8±5.7 years. Of the individuals with type 1 diabetes, 19.2% were diagnosed with at least one autoimmune disease vs 4.0% of the control group. The HRs for comorbidities within 19 years from onset of type 1 diabetes were 11.6 (95% CI 10.6, 12.6) for coeliac disease, 10.6 (95% CI 9.6, 11.8) for thyroid disease, 1.3 (95% CI 1.1, 1.6) for psoriasis, 4.1 (95% CI 3.2, 5.3) for vitiligo, 1.7 (95% CI 1.4, 2.2) for rheumatic joint disease, 1.0 (95% CI 0.8, 1.3) for inflammatory bowel disease, 1.0 (95% CI 0.7, 1.2) for systemic connective tissue disorder, 1.4 (95% CI 1.1, 1.9) for uveitis, 18.3 (95% CI 8.4, 40.0) for Addison’s disease, 1.8 (95% CI 0.9, 3.6) for multiple sclerosis, 3.7 (95% CI 1.6, 8.7) for inflammatory liver disease and 19.6 (95% CI 4.2, 92.3) for atrophic gastritis. Autoimmune disease in addition to type 1 diabetes had no statistically significant effect on HbA1c or mortality risk. Conclusions/interpretation: To our knowledge, this is the first comprehensive study where young individuals with type 1 diabetes were followed regarding development of a wide spectrum of autoimmune diseases, from onset of type 1 diabetes. In this nationwide and population-based study, there was already a high prevalence of autoimmune diseases in childhood, especially coeliac and thyroid disease. The presence of autoimmune comorbidity did not have a statistically significant effect on metabolic control or mortality risk. Graphical Abstract: [Figure not available: see fulltext.]
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| 9. |
- Aad, G., et al.
(författare)
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The ATLAS Experiment at the CERN Large Hadron Collider
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08003
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Forskningsöversikt (refereegranskat)abstract
- The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.
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| 10. |
- Abat, E., et al.
(författare)
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A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test
- 2011
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Ingår i: Journal of Instrumentation. - : Institute of Physics (IOP). - 1748-0221. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20 GeV and 180 GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.
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