| 1. |
- Adloff, C, et al.
(författare)
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Measurement of D*(+/-) meson production and F-2(c) in deep-inelastic scattering at HERA
- 2002
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 528:3-4, s. 199-214
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive production of D*+/-(2010) mesons in deep-inelastic scattering is studied with the HI detector at HERA. In the kinematic region 1 < Q(2) < 100 GeV2 and 0.05 < y < 0.7 an e(+) p cross section for inclusive D*+/- meson production of 8.50 +/- 0.42(stat.)(-100)(+1.21)(syst.) nb is measured in the visible range p(tD*) > 1.5 GeV and eta(D*) < 1.5. Single and double differential inclusive D*+/- meson cross sections are compared to perturbative QCD calculations in two different evolution schemes, The charm contribution to the proton structure, F-c(2)(x, Q(2)), is determined by extrapolating the visible charm cross section to the full phase space. This contribution is found to rise from about 10% at Q(2) = 1.5 GeV2 to more than 25% at Q(2) = 60 GeV2 corresponding to x values ranging from 5 x 10(-5) to 3 x 10(-3). (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Adloff, C, et al.
(författare)
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Measurement of dijet electroproduction at small jet separation
- 2002
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 24:1, s. 33-41
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Tidskriftsartikel (refereegranskat)abstract
- Deep-inelastic scattering data in the range 150 < Q(2) < 35000 GeV2 are used to investigate the minimum jet separation necessary to allow accurate description of the rate of dijet production using next-to-leading order perturbative QCD calculations. The required jet separation is found to be small, allowing about 1/3 of DIS data to be classified as dijet, as opposed to approximately 1/10 with more typical jet analyses. A number of precision measurements made using this dijet sample are well described by the calculations. The data are also described by the combination of leading order matrix elements and parton showers, as implemented in the QCD based Monte Carlo model RAPGAP.
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| 3. |
- Adloff, C, et al.
(författare)
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Search for excited neutrinos at HERA
- 2002
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 525:1-2, s. 9-16
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for excited neutrinos using e(-) p data taken by the H1 experiment at HERA at a center-of-mass energy of 318 GeV with an integrated luminosity of 15 pb(-1). No evidence for excited neutrino production is found. Mass dependent exclusion limits are determined for the ratio of the coupling to the compositeness scale, f/Lambda, independently of the relative couplings to the SU(2) and U(1) gauge bosons. These limits extend the excluded region to higher masses than has been possible in previous searches at other colliders.
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| 4. |
- Wallstrom, P, et al.
(författare)
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Serum concentrations of beta-carotene and alpha-tocopherol are associated with diet, smoking, and general and central adiposity
- 2001
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Ingår i: American Journal of Clinical Nutrition. - 1938-3207. ; 73:4, s. 777-785
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Previous studies of associations between diet, obesity, and blood concentrations of alpha-tocopherol and beta-carotene have been equivocal. Furthermore, most studies used only body mass index (BMI) as an obesity measure. OBJECTIVES: Our objectives were to examine the associations between energy and nutrient intakes, alcohol consumption, tobacco use, and serum cholesterol and serum concentrations of alpha-tocopherol and beta-carotene, and to examine the associations between different measures of general and central adiposity and serum concentrations of alpha-tocopherol and beta-carotene. DESIGN: This was a cross-sectional, population-based study of 253 men and 276 women aged 46-67 y. Nutrient data were collected by a modified diet history method. Measures of obesity included BMI, percentage of body fat (impedance analysis), waist-to-hip ratio, and waist circumference. The associations between serum nutrient concentrations and the other factors were examined by multiple linear regression. RESULTS: Twenty-one percent of men and 34% of women used antioxidant supplements. The mean BMI was 26.1 in men and 25.4 in women. Serum beta-carotene concentration was positively associated with serum cholesterol concentration, fiber intake, and beta-carotene intake, and negatively associated with smoking and all measures of obesity. In men, serum beta-carotene concentration was not significantly associated with central adiposity after adjustment for body fat. Serum alpha-tocopherol concentration was positively correlated with serum cholesterol, obesity, and vitamin E intake. In women, serum alpha-tocopherol concentration was also positively associated with intakes of ascorbic acid and selenium. Serum alpha-tocopherol concentration was associated with central adiposity after adjustment for body fat. CONCLUSION: Serum beta-carotene and alpha-tocopherol concentrations have different associations with diet, smoking, general adiposity, and central adiposity.
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| 5. |
- Lahmann, Martina, Docent i kemi, 1963-, et al.
(författare)
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A facile approach to diosgenin and furostan type saponins bearing a 3 beta-chacotriose moiety
- 2002
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 337:21-23, s. 2153-2159
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Tidskriftsartikel (refereegranskat)abstract
- Combination of a one-pot coupling technique and the use of benzyl ethers as permanent protecting groups offered a short and simple route to dioscin-type saponins. This strategy in combination with a mild reductive opening procedure of the spiroketal function in diosgenin also offered a convenient approach to bidesmosidic furostan type saponins. (Me3NBH3)-B-./AlCl3 promoted acetal opening of 3-O-TBDMS-protected diosgenin gave the 26-OH acceptor 9 into which a benzylated beta-glucose moiety was introduced by a S(N)2-type imidate coupling. After cleavage of the silyl ether, the 3beta-O-glucose and the 4-O-linked rhamnose of the chacotriose unit were introduced by a NIS/AgOTf-promoted one-pot coupling sequence utilising thioglycoside donors and their different reactivity in different solvents. After removal of a benzoyl group, the same coupling conditions were also used for the coupling of the second 2-O-linked rhamnose unit. The target substance was obtained after cleavage of the protecting benzyl ethers under Birch-type conditions, which did not affect the double bond in the steroid skeleton.
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