| 1. |
- Abreu, P., et al.
(författare)
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Measurement of the gluon fragmentation function and a comparison of the scaling violation in gluon and quark jets
- 2000
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 13:4, s. 573-589
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Tidskriftsartikel (refereegranskat)abstract
- The fragmentation functions of quarks and gluons are measured in various three-jet topologies in Z decays from the full data set collected with the DELPHI detector at the Z resonance between 1992 and 995. The results at different values of transverse momentum-like scales are compared. A parameterization of the quark and gluon fragmentation functions at a fixed reference scale is given. The quark and gluon fragmentation functions show the predicted pattern of scaling violations. The scaling violation for quark jets as a function of a transverse momentum-like scale is in a good agreement with that observed in lower energy e+e- annihilation experiments. For gluon jets it appears to be significantly stronger. The scale dependences of the gluon and quark fragmentation functions agree with the prediction of the DGLAP evolution equations from which the colour factor ratio CA/CF is measured to be: CA/CF = 2.26 ± 0.09stat. ± 0.06sys. ± 0.12clus.,scale..
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| 2. |
- Abreu, P., et al.
(författare)
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Study of dimuon production in photon-photon collisions and measurement of QED photon structure functions at LEP
- 2001
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 19:1, s. 15-28
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Tidskriftsartikel (refereegranskat)abstract
- Muon pair production in the process e+e- → e+e- μ+μ- is studied using the data taken at LEP1 (√s ≃ mz) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb-1. The QED predictions have been tested over the whole Q2 range accessible at LEP1 (from several GeV2/c4 to several hundred GeV2/c4) by comparing experimental distributions with distributions resulting from Monte Carlo simulations using various generators. Selected events are used to extract the leptonic photon structure function Fγ 2. Azimuthal correlations are used to obtain information on additional structure functions, Fγ A and Fγ B, which originate from interference terms of the scattering amplitudes. The measured ratios Fγ A/Fγ 2 and FγB/Fγ 2 are significantly different from zero and consistent with QED predictions.
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| 3. |
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| 4. |
- Bower, K. N., et al.
(författare)
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ACE-2 HILLCLOUD. An overview of the ACE-2 ground-based cloud experiment
- 2000
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Ingår i: Tellus. Series B: Chemical and Physical Meteorology. - : Stockholm University Press. - 0280-6509. ; 52:2, s. 750-778
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Tidskriftsartikel (refereegranskat)abstract
- The ACE-2 HILLCLOUD experiment was carried out on the island of Tenerife in June-July 1997 to investigate the interaction of the boundary layer aerosol with a hill cap cloud forming over a ridge to the north-east of the island. The cloud was used as a natural flow through reactor to investigate the dependence of the cloud microphysics and chemistry on the characteristics of the aerosols and trace gases entering cloud, and to simultaneously study the influence of the physical and chemical processes occurring within the cloud on the size distribution, chemical and hygroscopic properties of the aerosol exiting cloud. 5 major ground base sites were used, measuring trace gases and aerosols upwind and downwind of the cloud, and cloud microphysics and chemistry and interstitial aerosol and gases within the cloud on the hill. 8 intensive measurement periods or runs were undertaken during cloud events, (nocturnally for seven of the eight runs) and were carried out in a wide range of airmass conditions from clean maritime to polluted continental. Polluted air was characterised by higher than average concentrations of ozone (> 50 ppbv), fine and accumulation mode aerosols (> 3000 and > 1500 cm -3 , respectively) and higher aerosol mass loadings. Cloud droplet number concentrations N, increased from 50 cm -3 in background maritime air to > 2500 cm -3 in aged polluted continental air, a concentration much higher than had previously been detected. Surprisingly, N was seen to vary almost linearly with aerosol number across this range. The droplet aerosol analyser (DAA) measured higher droplet numbers than the corrected forward scattering spectrometer probe (FSSP) in the most polluted air, but at other times there was good agreement (FSSP = 0.95 DAA with an r 2 = 0.89 for N < 1200 cm -3 ). Background ammonia gas concentrations were around 0.3 ppbv even in air originating over the ocean, another unexpected but important result for the region. NO 2 was present in background concentrations of typically 15 pptv to 100 pptv and NO 3 . (the nitrate radical) was observed at night throughout. Calculations suggest NO 3 . losses were mainly by reaction with DMS to produce nitric acid. Low concentrations of SO 2 (~30 pptv), HNO 3 and HCl were always present. HNO 3 concentrations were higher in polluted episodes and calculations implied that these exceeded those which could be accounted for by NO 2 oxidation. It is presumed that nitric and hydrochloric acids were present as a result of outgassing from aerosol, the HNO 3 from nitrate rich aerosol transported into the region from upwind of Tenerife, and HCl from sea salt aerosol newly formed at the sea surface. The oxidants hydrogen peroxide and ozone were abundant (i.e., were well in excess over SO 2 throughout the experiment). Occasions of significant aerosol growth following cloud processing were observed, particularly in cleaner cases. Observations and modelling suggested this was due mainly to the take up of nitric acid, hydrochloric acid and ammonia by the smallest activated aerosol particles. On a few occasions a small contribution was made by the in-cloud oxidation of S(IV). The implications of these results from HILLCLOUD for the climatologically more important stratocumulus Marine Boundary Layer (MBL) clouds are considered.
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| 14. |
- Skari, H, et al.
(författare)
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Congenital diaphragmatic hernia: a survey of practice in Scandinavia
- 2004
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Ingår i: Pediatric Surgery International. - : Springer Science and Business Media LLC. - 1437-9813 .- 0179-0358. ; 20:5, s. 309-313
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Tidskriftsartikel (refereegranskat)abstract
- There is no consensus on the treatment of congenital diaphragmatic hernia (CDH), and practice seems to vary between centres. The main purpose of the present study was to survey current practice in Scandinavia. Thirteen paediatric surgical centres serving a population of about 22 million were invited, and all participated. One questionnaire was completed at each centre. The questionnaire evaluated management following prenatal diagnosis, intensive care strategies, operative treatment, and long-term follow-up. Survival data (1995-1998) were available from 12 of 13 centres. Following prenatal diagnosis of CDH, vaginal delivery and maternal steroids were used at eight and six centres, respectively. All centres used high-frequency oscillation ventilation (HFOV), nitric oxide (NO), and surfactant comparatively often. Five centres had extracorporeal membrane oxygenation (ECMO) facilities, and four centres transferred ECMO candidates. The majority of centres (7/9) always tried HFOV before ECMO was instituted. Surgery was performed when the neonate was clinically stable (11/13) and when no signs of pulmonary hypertension were detected by echo-Doppler (6/13). The repair was performed by laparotomy at all centres and most commonly with nonabsorbable sutures (8/13). Thoracic drain was used routinely at seven centres. Long-term follow-up at a paediatric surgical centre was uncommon (3/13). Only three centres treated more than five CDH patients per year. Comparing survival in centres treating more than five with those treating five or fewer CDH patients per year, there was a tendency towards better survival in the higher-volume centres (72.4%) than in the centres with lower volume (58.7%), p =0.065.
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| 15. |
- Tiselius, Peter, 1958, et al.
(författare)
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Functional response of Oikopleura dioica to house clogging due to exposure to algae of different sizes
- 2003
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Ingår i: Marine Biology. - 0025-3162. ; 142:2, s. 253-261
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Tidskriftsartikel (refereegranskat)abstract
- The functional response of the appendicularian Oikopleura dioica was investigated with a unialgal diet (Isochrysis galbana, 0-1,600 mug Cl-1) and with additions of specific concentrations of algae either smaller than the incurrent filter mesh size (Rhodomonas baltica, 90 mug Cl-1; Thalassiosira weissflogii, 60 mug Cl-1) or larger algae (Ceratium lineatum, 8 mug Cl-1; C. tripos, 52 mug C l(-1)). Clearance ranged from 0.13 to 3.3 ml mug C-1 h(-1) and followed a Michaelis-Menten curve corresponding to a maximum filtration rate (particles collected by both animal and house), FRmax = 164 ng C mug C-1 h(-1) and K-m = 64 mug C l(-1). Maximum pellet production was 9 pellets ind(-1) h(-1) and occurred at 100 mugC (-1). Pellet production was proportional to filtration rate below this level, but declined at higher concentrations. House production ranged from 0.5 to 5.5 houses ind(-1) day(-1) and the corresponding curve fit resulted in H-max = 4.6 houses ind(-1) day(-1) and K-m house = 32 mug Cl-1. Addition of edible small algae caused increased internal clogging of the houses, evidenced by significantly higher pigment concentrations in abandoned houses than in houses produced with I.. galbana as a single food. House production was not affected. In contrast, larger algae caused a significantly higher house production, but the algae were not collected on the houses. Increased levels of edible algae will not have negative effects on O. dioica at ecologically realistic concentrations. Ambient bloom concentrations of larger algae may, however, have a negative effect on the growth of O. dioica populations, owing to the compensatory increased house production.
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| 16. |
- Vallon-Christersson, J, et al.
(författare)
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Functional analysis of BRCA1 C-terminal missense mutations identified in breast and ovarian cancer families
- 2001
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 10:4, s. 60-353
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Tidskriftsartikel (refereegranskat)abstract
- Germline mutations in the breast and ovarian cancer susceptibility gene BRCA1 are responsible for the majority of cases involving hereditary breast and ovarian cancer. Whereas all truncating mutations are considered as functionally deleterious, most of the missense variants identified to date cannot be readily distinguished as either disease-associated mutations or benign polymorphisms. The C-terminal domain of BRCA1 displays an intrinsic transactivation activity, and mutations linked to disease predisposition have been shown to confer loss of such activity in yeast and mammalian cells. In an attempt to clarify the functional importance of the BRCA1 C-terminus as a transcription activator in cancer predisposition, we have characterized the effect of C-terminal germline variants identified in Scandinavian breast and ovarian cancer families. Missense variants A1669S, C1697R, R1699W, R1699Q, A1708E, S1715R and G1738E and a truncating mutation, W1837X, were characterized using yeast- and mammalian-based transcription assays. In addition, four additional missense variants (V1665M, D1692N, S1715N and D1733G) and one in-frame deletion (V1688del) were included in the study. Our findings demonstrate that transactivation activity may reflect a tumor-suppressing function of BRCA1 and further support the role of BRCA1 missense mutations in disease predisposition. We also report a discrepancy between results from yeast- and mammalian-based assays, indicating that it may not be possible to unambiguously characterize variants with the yeast assay alone. We show that transcription-based assays can aid in the characterization of deleterious mutations in the C-terminal part of BRCA1 and may form the basis of a functional assay.
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| 17. |
- Vargas, C. A., et al.
(författare)
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Importance of copepods versus appendicularians in vertical carbon fluxes in a Swedish fjord
- 2002
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Ingår i: Marine Ecology-Progress Series. - 0171-8630. ; 241, s. 125-138
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Tidskriftsartikel (refereegranskat)abstract
- We examined and quantified the contributions of copepods and appendicularians to the vertical flux of carbon during autumn and spring in Gullmar Fjord (west coast of Sweden). Faecal pellet-production rate was determined for major copepod and appendicularian species. In addition, house-production rates were estimated for the appendicularian Oikopleura dioica. Vertical flux of pigments, faecal carbon and appendicularian houses were measured using short-term (24 h) deployments of sediment traps at 2 depths (15 and 30 m). Copepods dominated the community biomass in both spring and autumn and their pellets dominated the faecal carbon flux. O. dioica houses with attached detritus were an important component of the biogenic carbon flux in October (15.3 mg C m(-2) d(-1)), equalling the contribution from copepods at 15 m and 50% of the flux at 30 m. At that time, we observed a loss rate of 70% d(-1) of the houses produced in the water column. In the spring, although Fritillaria borealis dominated the appendicularians, its houses did not appear to contribute to the biogenic flux. Our results suggest that oikopleurids and fritillariids may not operate equivalently in biogeochemical cycles. Because of the significant contribution of appendicularians to carbon fluxes, they should be incorporated in future flow models of coastal oceans.
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| 21. |
- Jacobsson, A., et al.
(författare)
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The effect of packaging material on the sensory properties of broccoli.
- 2003
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Ingår i: ISHS Acta Horticulturae. - 0567-7572. ; 599, s. 323-323
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Konferensbidrag (refereegranskat)abstract
- Three different commercially available polymeric films were studied to determine their effect on the sensory properties of fresh broccoli (Brassica oleracea L. var. Italica cv. ‘Marathon’). The polymer materials investigated were oriented polypropylene (OPP), polyvinyl chloride (PVC) and one low density polyethylene (LDPE) which contained an ethylene absorber. The fresh broccoli was packaged and stored for one week at 10°C or 3 days at 4°C followed by 4 days at 10°C. The oxygen and carbon dioxide concentrations inside the packages were monitored during storage. After storage the broccoli was evaluated according to sensory analyses, i.e. triangle test and quantitative descriptive analysis, by an analytical panel. The panel judged the broccoli according to smell, taste, texture and appearance. The triangle test showed significant differences between the smell of the broccoli samples, stored in the different packaging materials, when cooked. However, no differences between the raw broccoli, stored in the different packaging materials could be detected. The quantitative descriptive analysis showed that the following attributes; fresh smell and taste, chewing resistance, and crispness, differed significantly between the packaged broccoli when cooked. The appearance was shown to be the sensory property of broccoli most affected by the storage conditions, i.e. packaging material used and storage temperature. The results indicated the importance of the packaging material for maintaining the broccoli quality. However, one packaging material that was able to maintain all the studied sensory properties could not be identified.
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| 22. |
- Maar, M., et al.
(författare)
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Trophodynamic function of copepods, appendicularians and protozooplankton in the late summer zooplankton community in the Skagerrak
- 2004
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 144:5, s. 917-933
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Tidskriftsartikel (refereegranskat)abstract
- The study was carried out in the Skagerrak during late summer when population development in the pelagic cycle culminated in the yearly maximum in zooplankton biomass. The cyclonic circulation of surface water masses created the characteristic dome-shaped pycnocline across the Skagerrak. The large dinoflagellate Ceratium furca dominated the phytoplankton biomass. Ciliates and heterotrophic dinoflagellates were the major grazers and, potentially, consumed 43-166% of daily primary production. The grazing impact of copepods was estimated from specific egg production rates and grazing experiments. The degree of herbivory differed between species (14-85%), but coprophagy (e.g. feeding on fecal pellets) and ingestion of microzooplankton were also important. The appendicularian Oikopleura dioica was present in lower numbers than copepods, but cleared a large volume of water. The grazing impact of copepods and O. dioica was estimated to 57+/-24% and 12+/-12% of daily primary production, respectively. Sedimentation of organic material (30 m) varied between 169 and 708 mg C m(-2) day(-1), and the contribution from the mesozooplankton (copepod fecal pellets and mucus houses with attached phytodetritus of O. dioica) was 5-33% of this sedimentation. Recycling of fecal pellets and mucus houses in the euphotic zone was 59% and 36%, respectively. However, there was a high respiration of organic material by microorganisms in the mid-water column, and 34% of the sedimenting material actually reached the benthic community in the deep, central part of the Skagerrak.
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| 23. |
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| 25. |
- Rosén, Christian, et al.
(författare)
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On-line estimation of nitrification and denitrification capacity at Avedøre wastewater treatment plant
- 2004
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Konferensbidrag (refereegranskat)abstract
- In this paper, on-line nitrification and denitrification rate estimation in an alternating wastewater treatment plant is discussed. The nitrification/denitrification rates are estimated on-line using continuous measurements of ammonia and nitrate. From the rate estimates, the plant capacity is derived. This information is useful in various ways: for early warning to prevent severe disturbances such as nitrification inhibition; for optimising phase lengths and distribution of the phases in the alternating operation; and directly for the control system of the treatment plant. The estimation is based on the derivatives of the measurement signals combined with a simplified model of nitrogen dynamics of the plant. In the paper, we show examples of a successful application of the estimation methods to full-scale operation of the treatment plant and are today incorporated in the control system.
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| 26. |
- Roy, A, et al.
(författare)
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Excess tryptophan hydroxylase 17 779C allele in surviving cotwins of monozygotic twin suicide victims
- 2001
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Ingår i: Neuropsychobiology. - : S. Karger AG. - 0302-282X .- 1423-0224. ; 43:4, s. 233-236
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Tidskriftsartikel (refereegranskat)abstract
- <i>Objective:</i> To evaluate the relationship of the tryptophan hydroxylase (TPH) genotype to suicidality by the study of surviving monozygotic (MZ) cotwins of twins who committed suicide. <i>Method:</i> Twenty-four surviving Swedish MZ twins whose MZ cotwins had committed suicide were compared to 158 demographically sampled Swedish general population controls for TPH alleles. We also examined serotonin transporter alleles. <i>Results:</i> The living MZ cotwins of suicide victims had a significantly higher TPH 17 779C allele frequency than controls. No significant difference was observed for serotonin transporter alleles. <i>Conclusion: </i>These results, in a small sample, suggest the possibility that the 17 779C allele of the TPH gene may be associated with an increased risk of suicide. Further studies in larger samples are needed.
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| 27. |
- Syrjäsuo, M., Pulkkinen, T.I., Pellinen, R.P., Janhunen, P., Kauristie, K., Viljanen, A., Opgenoorth, H.J., Karllson, P., Wallman, S., Eglitis, P., Nielsen, E. and Thomas, C.
(författare)
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Observations of substorm electrodynamics using the miracle network.
- 2001
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Ingår i: The 4th International Conference on Substorms, ICS4. - : Terra Scient. Publ. Comp. Tokyo, Japan. Kaje Hamana, Japan.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 28. |
- Von, Sydow L.M., et al.
(författare)
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Natural background levels of trifluoroacetate in rain and snow
- 2000
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 34:15, s. 3115-3118
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Tidskriftsartikel (refereegranskat)abstract
- It has been shown that some of the fluorinated ethane derivatives being introduced as CFC-replacements can be transformed to TFA (trifluoroacetate) in the atmosphere. Moreover, TFA is extremely stable in the environment, and this has raised questions regarding how widespread TFA is in the environment. We found that TFA is ubiquitous in precipitation: samples of rain from Ireland and Poland and snow from Canada, Sweden, New Zealand, and East Antarctica contained 1-1100 ng/L, and, studying a firn core drilled in Antarctica, concentrations of 3-56 ng/L were measured in layers formed during the 19th century. We have confirmed the preindustrial presence of significant background concentrations of trifluoroacetate in historic precipitation samples from the analysis of firn. Extensive procedures were enforced to prevent sample contamination.It has been shown that some of the fluorinated ethane derivatives being introduced as CFC-replacements can be transformed to TFA (trifluoroacetate) in the atmosphere. Moreover, TFA is extremely stable in the environment, and this has raised questions regarding how widespread TFA is in the environment. We found that TFA is ubiquitous in precipitation: samples of rain from Ireland and Poland and snow from Canada, Sweden, New Zealand, and East Antarctica contained 1-1100 ng/L, and, studying a firn core drilled in Antarctica, concentrations of 3-56 ng/L were measured in layers formed during the 19th century. We have confirmed the preindustrial presence of significant background concentrations of trifluoroacetate in historic precipitation samples from the analysis of firn. Extensive procedures were enforced to prevent sample contamination.
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