| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Acciari, V. A., et al.
(författare)
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Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5939, s. 444-448
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Tidskriftsartikel (refereegranskat)abstract
- The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.
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| 3. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 4. |
- Wild, W., et al.
(författare)
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Millimetron—a large Russian-European submillimeter space observatory
- 2009
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:1, s. 221-244
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Tidskriftsartikel (refereegranskat)abstract
- Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
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| 12. |
- Gulz, Agneta, et al.
(författare)
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Virtual pedagogical agents - design guidelines regarding visual appearance and pedagogical roles
- 2006
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Ingår i: [Host publication title missing]. - 8469024698 ; 3, s. 1848-1852
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Konferensbidrag (refereegranskat)abstract
- Following a brief discussion on aspects of visual appearance and roles respectively, two user studies are presented and discussed. Both focus on learner experiences and explore the reciprocal relation between visual appearance of virtual agents and their pedagogical roles. The paper concludes with some preliminary guidelines for the early stages of the design process of virtual pedagogical agents.
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| 13. |
- Mazzali, P. A., et al.
(författare)
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High-Velocity Features : A Ubiquitous Property of Type Ia Supernovae
- 2005
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 623, s. L37-L40
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Tidskriftsartikel (refereegranskat)abstract
- Evidence of high-velocity features (HVFs) such as those seen in the near-maximum spectra of some Type Ia supernovae (SNe Ia; e.g., SN 2000cx) has been searched for in the available SN Ia spectra observed earlier than 1 week before B maximum. Recent observational efforts have doubled the number of SNe Ia with very early spectra. Remarkably, all SNe Ia with early data (seven in our Research Training Network sample and 10 from other programs) show signs of such features, to a greater or lesser degree, in Ca II IR and some also in the Si II λ6355 line. HVFs may be interpreted as abundance or density enhancements. Abundance enhancements would imply an outer region dominated by Si and Ca. Density enhancements may result from the sweeping up of circumstellar material (CSM) by the highest velocity SN ejecta. In this scenario, the high incidence of HVFs suggests that a thick disk and/or a high-density companion wind surrounds the exploding white dwarf, as may be the case in single degenerate systems. Large-scale angular fluctuations in the radial density and abundance distribution may also be responsible: this could originate in the explosion and would suggest a deflagration as the more likely explosion mechanism. CSM interaction and surface fluctuations may coexist, possibly leaving different signatures on the spectrum. In some SNe, the HVFs are narrowly confined in velocity, suggesting the ejection of blobs of burned material.
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| 14. |
- Mendez, M. A., et al.
(författare)
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Cereal fiber intake may reduce risk of gastric adenocarcinomas: The EPIC-EURGAST study
- 2007
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 121:7, s. 1618-1623
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Tidskriftsartikel (refereegranskat)abstract
- Numerous case-control studies suggest dietary fiber may reduce risk of gastric cancer, but this has not been confirmed prospectively. A previous case-control study reported reduced risk of gastric cardia adenocarcinomas associated with cereal fiber, but not with fruit or vegetable fiber. To date, different food sources of fiber have not been examined with respect to noncardia tumors or diverse histologic sub-types. This study prospectively examines associations between fiber from different food sources and incident gastric adenocarcinomas (GC) among more than 435,000 subjects from 10 countries participating in the European Prespective Investigation into Cancer and Nutrition study. Subjects aged 25-70 years completed dietary questionnaires in 1992-98, and were followed up for a median of 6.7 years. About 312 incident GCs were observed. The relative risk of GC was estimated based on cohort-wide sex-specific fiber intake quartiles using proportional hazards models to estimate hazards ratios (HRs) and 95% confidence intervals (CIs). Intakes of cereal fiber, but not total, fruit or vegetable fiber, were associated with reduced GC risk [adjusted HR for the highest vs. lowest quartile of cereal fiber 0.69, 0.48-0.99]. There was a strong inverse association for diffuse [HR 0.43, 0.22-0.86], but not intestinal type [HR 0.98, 0.54-1.80] tumors. Associations for cardia vs. noncardia tumors were similar to those for overall GC, although cardia associations did not reach significance. Cereal fiber consumption may help to reduce risk of GC, particularly diffuse type tumors. Further study on different food sources of fiber in relation to GC risk is warranted to confirm these relationships.
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| 15. |
- Ossiannilsson, Ebba, et al.
(författare)
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Web 2.0 to Encourage Usability of GIS (Geographical Information Systems) in Society – the eGIS+ Project
- 2009
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Ingår i: Research, Reflections and Innovations in Integrating ICT in Education. - 9788469217900 - 9788469217887 ; 2, s. 1131-1135
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- GIS applications are nowadays used in nearly every area of society and the need for GIS competence is therefore increasing over all. Micro-training and open educational resources are important concepts to reach new target groups, not least from a higher education perspective. The use of Web 2.0 creates possibilities for a more user friendly approach and for broader outreach. The eGIS+ project addresses the question of how to capture the interest of children and new groups for GIS and to offer GIS competence with a high level of flexibility in time, space and study pace.
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| 16. |
- Preston, R J S, et al.
(författare)
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Selective modulation of protein C affinity for EPCR and phospholipids by Gla domain mutation
- 2005
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 272:1, s. 97-108
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Tidskriftsartikel (refereegranskat)abstract
- Uniquely amongst vitamin K-dependent coagulation proteins, protein C interacts via its Gla domain both with a receptor, the endothelial cell protein C receptor (EPCR), and with phospholipids. We have studied naturally occurring and recombinant protein C Gla domain variants for soluble (s)EPCR binding, cell surface activation to activated protein C (APC) by the thrombin-thrombomodulin complex, and phospholipid dependent factor Va (FVa) inactivation by APC, to establish if these functions are concordant. Wild-type protein C binding to sEPCR was characterized with surface plasmon resonance to have an association rate constant of 5.23x10(5) M-1.s(-1), a dissociation rate constant of 7.61x10(-2) s(-1) and equilibrium binding constant (K-D) of 147 nM. It was activated by thrombin over endothelial cells with a K-m of 213 nM and once activated to APC, rapidly inactivated FVa. Each of these interactions was dramatically reduced for variants causing gross Gla domain misfolding (R-1L, R-1C, E16D and E26K). Recombinant variants Q32A, V34A and D35A had essentially normal functions. However, R9H and H10Q/S11G/S12N/D23S/Q32E/N33D/H44Y (QGNSEDY) variants had slightly reduced (
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| 17. |
- Altavilla, G., et al.
(författare)
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Type Ia SNe Along Redshift : The \mathcal {R}(Si II) Ratio and the Expansion Velocities in Intermediate-z Supernovae
- 2009
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 695, s. 135-148
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of intermediate-z Type Ia supernovae (SNe Ia) using empirical physical diagrams which permit the investigation of those SNe explosions. This information can be very useful to reduce systematic uncertainties of the Hubble diagram of SNe Ia up to high z. The study of the expansion velocities and the measurement of the ratio \mathcal {R}(Si II) allow subtyping of SNe Ia as done in nearby samples. The evolution of this ratio as seen in the diagram \mathcal {R}(Si II)-(t) together with \mathcal {R}(Si II)max versus (B - V)0 indicates consistency of the properties at intermediate-z compared with the nearby SNe Ia. At intermediate-z, expansion velocities of Ca II and Si II are found similar to those of the nearby sample. This is found in a sample of six SNe Ia in the range 0.033 <=z<= 0.329 discovered within the International Time Programme of SNe Ia for Cosmology and Physics in the spring run of 2002.7The program run under Omega and Lambda from Supernovae and the Physics of Supernova Explosions within the International Time Programme at the telescopes of the European Northern Observatory (ENO) at La Palma (Canary Islands, Spain). Two SNe Ia at intermediate-z were of the cool FAINT type, one being an SN1986G-like object highly reddened. The \mathcal {R}(Si II) ratio as well as subclassification of the SNe Ia beyond templates help to place SNe Ia in their sequence of brightness and to distinguish between reddened and intrinsically red supernovae. This test can be done with very high z SNe Ia and it will help to reduce systematic uncertainties due to extinction by dust. It should allow to map the high-z sample into the nearby one.
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| 18. |
- Costa, F., et al.
(författare)
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Management of neuroendocrine tumors : a meeting of experts from Latin America
- 2008
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 88:3, s. 235-42
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Tidskriftsartikel (refereegranskat)abstract
- A panel of experts from Latin America convened in Brazil, in May of 2007, for consensus recommendations regarding the management of neuroendocrine tumors (NETs) of the gastrointestinal tract and pancreas. The recently introduced World Health Organization classification of NETs represents a step forward, but the former classification of carcinoids into foregut, midgut and hindgut is still likely to be useful in the near future. Macroscopic description of the tumor should be followed by light microscopic examination and immunohistochemical staining, whereas other techniques might not be widely available in Latin America. Surgery remains the mainstay of treatment for patients with potentially curable tumors, and adequate selection is paramount in order to optimize treatment results. Regarding systemic therapy, patients with well-differentiated tumors or islet-cell carcinomas may be categorized as having indolent disease, while patients with poorly differentiated, anaplastic, and small-cell carcinomas, or with atypical carcinoids, may be approached initially as having aggressive disease. Somatostatin analogues play a cytostatic role in indolent tumors, and chemotherapy may play a role against other, more aggressive NETs. Obviously, there is an urgent need for novel therapies that are effective against NETs.
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| 19. |
- Friedenreich, Christine, et al.
(författare)
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Physical activity and risk of colon and rectal cancers: The European Prospective Investigation into Cancer and Nutrition
- 2006
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 15:12, s. 2398-2407
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Tidskriftsartikel (refereegranskat)abstract
- We investigated several aspects of the role of physical activity in colon and rectal cancer etiology that remain unclear in the European Prospective Investigation into Nutrition and Cancer. This cohort of 413,044 men and women had 1,094 cases of colon and 599 cases of rectal cancer diagnosed during an average of 6.4 years of follow-up. We analyzed baseline data on occupational, household, and recreational activity to examine associations by type of activity, tumor subsite, body mass index (BMI), and energy intake. The multivariate hazard ratio for colon cancer was 0.78 [95% confidence interval (95% CI), 0.59-1.03] among the most active participants when compared with the inactive, with evidence of a dose-response effect (P-trend = 0.04). For right-sided colon tumors, the risk was 0.65 (95% CI, 0.43-1.00) in the highest quartile of activity with evidence of a linear trend (P-trend=0.004). Active participants with a BMI under 25 had a risk of 0.63 (95% CI, 0.39-1.01) for colon cancer compared with the inactive. Finally, an interaction between BMI and activity (P-interaction=0.03) was observed for right-sided colon cancers; among moderately active and active participants with a BMI under 25, a risk of 0.38 (95% CI, 0.21-0.68) was found as compared with inactive participants with BMI > 30. No comparable decreased risks were observed for rectal cancer for any type of physical activity for any subgroup analyses or interactions considered. We found that physical activity reduced colon cancer risk, specifically for right-sided tumors and for lean participants, but not rectal cancer.
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| 20. |
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| 21. |
- Saenz-Mendez, Patricia, et al.
(författare)
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Theoretical prediction of binding modes and hot sequences for allopsoralen-DNA interaction
- 2007
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Ingår i: Chemical Physics Letters. - Amsterdam : Elsevier. - 0009-2614 .- 1873-4448. ; 450:1-3, s. 127-131
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Tidskriftsartikel (refereegranskat)abstract
- Molecular docking studies of two duplex DNA sequences as target fragments and allopsoralen as ligand were performed. The calculated interaction energies showed that the ligand can be docked into the minor groove as well as become intercalated. However, unlike psoralen, allopsoralen preferred binding mode for non-poly-TA sequences is minor groove binding. Calculated energies for intercalation between different base pairs suggest that the predicted sequence selectivity for allopsoralen is analogous to that observed for psoralen. Intercalation is favored in 5'-TpA sites in poly-TA sequences.
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| 22. |
- Saenz-Mendez, Patricia, et al.
(författare)
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Theoretical study of sequence selectivity and preferred binding mode of psoralen with DNA
- 2007
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Ingår i: Research Letters in Physical Chemistry. - : Hindawi Limited. - 1687-6873 .- 1687-6881. ; , s. Article number 60623-
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Tidskriftsartikel (refereegranskat)abstract
- Psoralen interaction with two models of DNA was investigated using molecular mechanics and molecular dynamics methods. Calculated energies of minor groove binding and intercalation were compared in order to define a preferred binding mode for the ligand.We found that both binding modes are possible, explaining the low efficiency for monoadduct formation from intercalated ligands. A comparison between the interaction energy for intercalation between different base pairs suggests that the observed sequence selectivity is due to favorable intercalation in 5'-TpA in (AT)n sequences.
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| 23. |
- Stanishev, Vallery, et al.
(författare)
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SN 2003du: 480 days in the life of a normal type Ia supernova
- 2007
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 469:2, s. 645-661
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Tidskriftsartikel (refereegranskat)abstract
- Aims.We present a study of the optical and near-infrared (NIR) properties of the Type Ia Supernova (SN Ia) 2003du.Methods: An extensive set of optical and NIR photometry and low-resolution long-slit spectra was obtained using a number of facilities. The observations started 13 days before B-band maximum light and continued for 480 days with exceptionally good time sampling. The optical photometry was calibrated through the S-correction technique.Results: The {UBVRIJHK} light curves and the color indices of SN 2003du closely resemble those of normal SNe Ia. SN 2003du reached a B-band maximum of 13.49 ± 0.02 mag on JD2 452 766.38 ± 0.5. We derive a B-band stretch parameter of 0.988 ±0.003, which corresponds to Δ m15=1.02 ±0.05, indicative of a SN Ia of standard luminosity. The reddening in the host galaxy was estimated by three methods, and was consistently found to be negligible. Using an updated calibration of the V and {JHK} absolute magnitudes of SNe Ia, we find a distance modulus μ=32.79±0.15 mag to the host galaxy, UGC 9391. We measure a peak {uvoir} bolometric luminosity of 1.35(±0.20)×1043 erg s-1 and Arnett's rule implies that M56Ni≃0.68 ±0.14 Mȯ of 56Ni was synthesized during the explosion. Modeling of the {uvoir} bolometric light curve also indicates M56Ni in the range 0.6-0.8 Mȯ. The spectral evolution of SN 2003du at both optical and NIR wavelengths also closely resembles normal SNe Ia. In particular, the Si II ratio at maximum R(Si II) = 0.22 ±0.02 and the time evolution of the blueshift velocities of the absorption line minima are typical. The pre-maximum spectra of SN 2003du showed conspicuous high-velocity features in the Ca II H&K doublet and infrared triplet, and possibly in Si II λ6355, lines. We compare the time evolution of the profiles of these lines with other well-observed SNe Ia and we suggest that the peculiar pre-maximum evolution of Si II λ6355 line in many SNe Ia is due to the presence of two blended absorption components.
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