| 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. |
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| 3. |
- Abbasi, R., et al.
(författare)
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The IceCube data acquisition system : Signal capture, digitization, and timestamping
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 601:3, s. 294-316
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Tidskriftsartikel (refereegranskat)abstract
- IceCube is a km-scale neutrino observatory under construction at the South Pole with sensors both in the deep ice (InIce) and on the surface (IceTop). The sensors, called Digital Optical Modules (DOMs). detect, digitize and timestamp the signals from optical Cherenkov-radiation photons. The DOM Main Board (MB) data acquisition subsystem is connected to the central DAQ in the IceCube Laboratory (ICL) by a single twisted copper wire-pair and transmits packetized data on demand. Time calibration is maintained throughout the array by regular transmission to the DOMs of precisely timed analog signals, synchronized to a central GPS-disciplined clock. The design goals and consequent features, functional capabilities, and initial performance of the DOM MB, and the operation of a combined array of DOMs as a system, are described here. Experience with the first InIce strings and the IceTop stations indicates that the system design and performance goals have been achieved. (c) 2009 Elsevier B.V. All rights reserved.
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| 4. |
- Abbasi, R., et al.
(författare)
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SEARCH FOR HIGH-ENERGY MUON NEUTRINOS FROM THE "NAKED-EYE" GRB 080319B WITH THE IceCube NEUTRINO TELESCOPE
- 2009
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 701:2, s. 1721-1731
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Tidskriftsartikel (refereegranskat)abstract
- We report on a search with the IceCube detector for high-energy muon neutrinos from GRB 080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.1 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, no excess was found above background. The 90% CL upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.5 x 10(-3) erg cm(-2) in the energy range between 120 TeV and 2.2 PeV, which contains 90% of the expected events.
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| 5. |
- Abbasi, R., et al.
(författare)
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Search for point sources of high energy neutrinos with final data from AMANDA-II
- 2009
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 79, s. 062001-
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for point sources of high energy neutrinos using 3.8 yr of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the northern sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E(-2) neutrino fluxes from points in the northern sky, with an average upper limit of E(2)Phi(nu mu)+nu(tau)<= 5.2x10(-11) TeV cm(-2) s(-1) on the sum of nu(mu) and nu(tau) fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.
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| 6. |
- Abbasi, R., et al.
(författare)
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Solar energetic particle spectrum on 2006 December 13 determined by IceTop
- 2008
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 689:1, s. L65-L68
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Tidskriftsartikel (refereegranskat)abstract
- On 2006 December 13 the IceTop air shower array at the South Pole detected a major solar particle event. By numerically simulating the response of the IceTop tanks, which are thick Cerenkov detectors with multiple thresholds deployed at high altitude with no geomagnetic cutoff, we determined the particle energy spectrum in the energy range 0.6-7.6 GeV. This is the first such spectral measurement using a single instrument with a well-defined viewing direction. We compare the IceTop spectrum and its time evolution with previously published results and outline plans for improved resolution of future solar particle spectra.
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| 7. |
- Abbasi, R, et al.
(författare)
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FIRST NEUTRINO POINT-SOURCE RESULTS FROM THE 22 STRING ICECUBE DETECTOR
- 2009
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Ingår i: Astrophysical Journal Letters. - 2041-8205. ; 701, s. L47-L51
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Tidskriftsartikel (refereegranskat)abstract
- We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-2008 with 22 strings of the IceCube detector (approximately one-fourth of the planned total) and 275.7 days of live time. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2 sigma after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E-2 spectrum is E-2 Phi(v mu) < 1.4 x 10(-11) TeV cm(-2) s(-1), in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of 2.
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| 8. |
- Abbasi, R, et al.
(författare)
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Limits on a Muon Flux from Neutralino Annihilations in the Sun with the IceCube 22-String Detector
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:20, s. 201302-
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Tidskriftsartikel (refereegranskat)abstract
- A search for muon neutrinos from neutralino annihilations in the Sun has been performed with the IceCube 22-string neutrino detector using data collected in 104.3 days of live time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured neutralinos in the Sun and converted to limits on the weakly interacting massive particle (WIMP) proton cross sections for WIMP masses in the range 250-5000 GeV. These results are the most stringent limits to date on neutralino annihilation in the Sun.
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| 9. |
- Abbasi, R, et al.
(författare)
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Determination of the atmospheric neutrino flux and searches for new physics with AMANDA-II
- 2009
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 79, s. 102005-
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Tidskriftsartikel (refereegranskat)abstract
- The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance or quantum decoherence. Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on violation of Lorentz invariance and quantum decoherence parameters using a maximum likelihood method. Given the absence of evidence for new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV.
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| 10. |
- Abbasi, R, et al.
(författare)
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Extending the Search for Neutrino Point Sources with IceCube above the Horizon
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:22, s. 221102-
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Tidskriftsartikel (refereegranskat)abstract
- Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.
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| 11. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 12. |
- Antinori, A., et al.
(författare)
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Updated research nosology for HIV-associated neurocognitive disorders
- 2007
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Ingår i: Neurology. ; 69:18, s. 1789-99
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Tidskriftsartikel (refereegranskat)abstract
- In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.
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| 13. |
- Bishop, D. Timothy, et al.
(författare)
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Genome-wide association study identifies three loci associated with melanoma risk
- 2009
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 41:8, s. 920-925
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Tidskriftsartikel (refereegranskat)abstract
- We report a genome-wide association study of melanoma conducted by the GenoMEL consortium based on 317K tagging SNPs for 1,650 selected cases and 4,336 controls, with replication in an additional two cohorts (1,149 selected cases and 964 controls from GenoMEL, and a population-based case-control study in Leeds of 1,163 cases and 903 controls). The genome-wide screen identified five loci with genotyped or imputed SNPs reaching P < 5 x 10(-7). Three of these loci were replicated: 16q24 encompassing MC1R (combined P = 2.54 x 10(-27) for rs258322), 11q14-q21 encompassing TYR (P = 2.41 x 10(-14) for rs1393350) and 9p21 adjacent to MTAP and flanking CDKN2A (P = 4.03 x 10(-7) for rs7023329). MC1R and TYR are associated with pigmentation, freckling and cutaneous sun sensitivity, well-recognized melanoma risk factors. Common variants within the 9p21 locus have not previously been associated with melanoma. Despite wide variation in allele frequency, these genetic variants show notable homogeneity of effect across populations of European ancestry living at different latitudes and show independent association to disease risk.
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| 14. |
- Liu, Y, et al.
(författare)
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Properties of porcine and recombinant human collagen matrices for optically clear tissue engineering applications
- 2006
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Ingår i: Biomacromolecules. - : American Chemical Society. - 1525-7797 .- 1526-4602. ; 7:6, s. 1819-1828
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Tidskriftsartikel (refereegranskat)abstract
- Porcine and recombinant human atelocollagen I solutions were cross-linked with a water soluble carbodiimide at various stoichiometries and collagen concentrations (5-20 w/w %). The resulting hydrogels were clear and, when used as cell growth matrices, allowed cell and nerve visualization in vitro and in vivo. We have previously reported that, after six months of implantation in pigs and rabbits corneas, these robust hydrogels allowed regeneration of host cells and nerves to give optically clear corneas with no detected loss in thickness, indicating stable engraftment. Here, the biocompatible hydrogel formulations leading to this novel in vivo performance were characterized for amine consumption, gel hydration, thermal properties, optical clarity, refractive index, nutrient diffusion, biodegradation, tensile measurements, and average pore diameters. Gels with excellent in vitro (epithelial overgrowth, neurite penetration) and in vivo performance (clarity, touch sensitivity regeneration) had 4-11 nm pores, yet had glucose and albumin diffusive coefficients similar to mammalian corneas and allowed neurite extension through the gels.
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