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- Amundadottir, Laufey, et al.
(författare)
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Genome-wide association study identifies variants in the ABO locus associated with susceptibility to pancreatic cancer.
- 2009
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 41, s. 986-990
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Tidskriftsartikel (refereegranskat)abstract
- We conducted a two-stage genome-wide association study of pancreatic cancer, a cancer with one of the lowest survival rates worldwide. We genotyped 558,542 SNPs in 1,896 individuals with pancreatic cancer and 1,939 controls drawn from 12 prospective cohorts plus one hospital-based case-control study. We conducted a combined analysis of these groups plus an additional 2,457 affected individuals and 2,654 controls from eight case-control studies, adjusting for study, sex, ancestry and five principal components. We identified an association between a locus on 9q34 and pancreatic cancer marked by the SNP rs505922 (combined P = 5.37 x 10(-8); multiplicative per-allele odds ratio 1.20; 95% confidence interval 1.12-1.28). This SNP maps to the first intron of the ABO blood group gene. Our results are consistent with earlier epidemiologic evidence suggesting that people with blood group O may have a lower risk of pancreatic cancer than those with groups A or B.
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| 4. |
- Reimold, W U, et al.
(författare)
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Laser argon dating of melt breccias from the Siljan impact structure, Sweden : Implications for a possible relationship to Late Devonian extinction events
- 2005
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Ingår i: Meteoritics and Planetary Science. - : Wiley. - 1086-9379 .- 1945-5100. ; 40:4, s. 591-607
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Tidskriftsartikel (refereegranskat)abstract
- In earlier studies, the 65-75 km diameter Si1jan impact structure in Sweden has been linked to the Late Devonian mass extinction event. The Siljan impact event has previously been dated by K-Ar and Ar-Ar chronology at 342-368 Ma, with the commonly quoted age being 362.7 +/- 2.2 Ma (2 sigma, recalculated using currently accepted decay constants). Until recently, the accepted age for the Frasnian/Famennian boundary and associated extinction event was 364 Ma, which is within error limits of this earlier Si1jan age. Here we report new Ar-Ar ages extracted by laser spot and laser step heating techniques for several melt breccia samples from Si1jan (interpreted to be impact melt breccia). The analytical results show some scatter, which is greater in samples with more extensive alteration; these samples generally yield younger ages. The two samples with the least alteration yield the most reproducible weighted mean ages: one yielded a laser spot age of 377.2 +/- 2.5 Ma (95% confidence limits) and the other yielded both a laser spot age of 376.1 +/- 2.8 Ma (95% confidence limits) and a laser stepped heating plateau age over 70.6% (39)Ar release of 377.5 +/- 2.4 Ma (2 sigma). Our conservative estimate for the age of Siljan is 377 2 Ma (95% confidence limits), which is significantly different from both the previously accepted age for the Frasnian/Famennian (F/F) boundary and the previously quoted age of Siljan. However, the age of the F/F boundary has recently been revised to 374.5 +/- 2.6 Ma by the International Commission for Stratigraphy, which is, within error, the same as our new age. However, the currently available age data are not proof that there was a connection between the Si1jan impact event and the F/F boundary extinction. This new result highlights the dual problems of dating meteorite impacts where fine-grained melt rocks are often all that can be isotopically dated, and constraining the absolute age of biostratigraphic boundaries, which can only be constrained by age extrapolation. Further work is required to develop and improve the terrestrial impact age record and test whether or not the terrestrial impact flux increased significantly at certain times, perhaps resulting in major extinction events in Earth's biostratigraphic record.
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- Frogner Kockum, Paul, et al.
(författare)
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A diverse ecosystem response to volcanic aerosols
- 2006
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Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541 .- 1872-6836. ; 231:1-2, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- Unexpectedly high aluminium concentrations beside fluoride and essential elements are released from metal salts adsorbed to volcanic ash. Through simulation of the mixing of pristine volcanic ash leachate with fresh water and seawater using PHREEQC, we found an increased potential toxicity in fresh waters through the combination of high aluminium and fluoride concentrations. Owing to the mixing of acid ash leachate with fresh water, aluminofluoride complexes (AlFx+ 3−x) persist in aqueous systems with low turnover rates, and could be toxic to both plants and animals. In contrast, due to the well-buffered and relatively high pH in seawater, the speciation of the ash leachate/seawater mixture shows that complexes of fluoride and aluminium (i.e. AlFx+ 3−x) will not dominate in a well-mixed marine system; instead, Al(OH)x+ 3−x species will occur at greatest concentration. Consequently, compared with fresh water environments, the mixing of ash leachate with seawater indicates reduced toxic effects due to decreased formation of AlFx+ 3−x complexes and the low solubility of Al-hydroxides. In addition, the deposition of volcanic aerosols may enhance biological activity in the marine environment by providing micronutrients as some oceanic phytoplankton species tolerates extreme concentrations of fluoride (F).
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| 8. |
- Henkel, Herbert, et al.
(författare)
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Geophysical investigations of the Siljan impact structure - A short review
- 2005
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Ingår i: IMPACT TECTONICS. - Berlin/Heidelberg : Springer-Verlag. - 3540241817 ; , s. 247-283
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Konferensbidrag (refereegranskat)abstract
- Siljan in southwest Sweden is the largest impact structure in western Europe, with a present topographic diameter of ca. 75 km. Recent age determinations indicate an age of 377 Ma. The bedrock geology of the region has recently been re-mapped by the Geological Survey of Sweden in the scale of 1:50 000. There is now complete coverage with airborne geophysics. New maps of the geophysical data have been prepared for this review. In connection with the Deep Gas Project, further geophysical studies were made and two drill holes were sunk to over 6 kin depth in the central uplift of the structure. The Deep Gas Project produced a large number of reports and publications, which are listed in the summary report of Juhlin (1991). Some of the results are compiled and shortly summarized here. Digital elevation data are available with 50 in spatial resolution, and a gray tone map has been prepared with the regional trend removed. A profile of these data shows that the peak ring of the structure is still visible in the morphology.
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| 10. |
- Hicks, E.M., et al.
(författare)
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Controlling plasmon line shapes through diffractive coupling in linear arrays of cylindrical nanoparticles fabricated by electron beam lithography
- 2005
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 5:6, s. 1065-1070
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Tidskriftsartikel (refereegranskat)abstract
- The effect of diffractive coupling on the collective plasmon line shape of linear arrays of Ag nanoparticles fabricated by electron beam lithography has been investigated using Rayleigh scattering spectroscopy. The array spectra exhibit an intricate multi-peak structure, including a narrow mode that gains strength for interparticle distances that are close to the single particle resonance wavelength. A version of the discrete dipole approximation method provides an excellent qualitative description of the observed behavior.
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