| 1. |
- Schaad, K, et al.
(författare)
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FISH mapping of i(7q) in acute leukemias and myxoid liposarcoma reveals clustered breakpoints in 7p11.2 : implications for formation and pathogenetic outcome of the idic(7)(p11.2)
- 2006
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Ingår i: Cytogenetic and Genome Research. - : S. Karger AG. - 1424-859X .- 1424-8581. ; 114:2, s. 126-130
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Tidskriftsartikel (refereegranskat)abstract
- Isochromosome 7q - i(7q) - is seen in a wide variety of hematologic malignancies and solid tumors, often as a secondary change to a characteristic primary translocation. Despite its high frequency, nothing is known about the formation and the pathogenetic outcome of this abnormality. To address these issues, we performed a detailed fluorescence in situ hybridization (FISH) investigation of four acute lymphoblastic leukemias, one acute myeloid leukemia, and two myxoid liposarcomas with i(7q). Using FISH with bacterial artificial chromosomes (BACs) mapping between 7p12.2 and 7q11.2, the breakpoints (BPs) in all seven cases were shown to cluster to an approximately 340 kb segment at 7p11.2, covered by the overlapping BAC probes RP11-760D2 and RP11-10F11. Thus, the i(7q) should formally be designated idic(7) (p11.2). In one of the cases, FISH with fosmids could narrow down the BP further to an 80-kb sequence delineated by G248P81983A10 and G248P8793H7. No known genes are located in the 340-kb BP cluster region, indicating that the idic(7)(p11.2) does not result in a fusion or deregulation of genes in this segment. The pathogenetically important outcome is thus likely to be an altered gene expression because of copy number changes. The clustering of breakpoints might be due to frequent intrachromosomal duplicons in the BP region.
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| 2. |
- Aad, G., et al.
(författare)
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- 2015
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Aartsen, M. G., et al.
(författare)
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Neutrino interferometry for high-precision tests of Lorentz symmetry with IceCube
- 2018
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Ingår i: Nature Physics. - : NATURE PUBLISHING GROUP. - 1745-2473 .- 1745-2481. ; 14:9, s. 961-966
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Tidskriftsartikel (refereegranskat)abstract
- Lorentz symmetry is a fundamental spacetime symmetry underlying both the standard model of particle physics and general relativity. This symmetry guarantees that physical phenomena are observed to be the same by all inertial observers. However, unified theories, such as string theory, allow for violation of this symmetry by inducing new spacetime structure at the quantum gravity scale. Thus, the discovery of Lorentz symmetry violation could be the first hint of these theories in nature. Here we report the results of the most precise test of spacetime symmetry in the neutrino sector to date. We use high-energy atmospheric neutrinos observed at the IceCube Neutrino Observatory to search for anomalous neutrino oscillations as signals of Lorentz violation. We find no evidence for such phenomena. This allows us to constrain the size of the dimension-four operator in the standard-model extension for Lorentz violation to the 10(-28) level and to set limits on higher-dimensional operators in this framework. These are among the most stringent limits on Lorentz violation set by any physical experiment.
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| 4. |
- Aartsen, Marja, et al.
(författare)
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The future of greying Europe : Conclusion
- 2013
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Ingår i: Old age in Europe. - Dordrecht : Springer Netherlands. - 9789400761346 - 9789400761339 ; , s. 131-136
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Bokkapitel (refereegranskat)abstract
- Although Europe’s population is greying, the future of Europe does not look grey. What can be learned from this book is that old age is not necessarily characterized by frailty and decline, but instead can be a time of self-fulfillment, activity, and social participation. Moreover, we now know that population ageing does not need to threaten extant social and welfare state-related institutions, but instead opens up potentials for restructuring and reinvention. Life expectancy is longer than ever before and living conditions that enhance healthy ageing have very much improved. New technologies and Information and Communication Technologies may assist older people to stay in their homes longer. The growing possibilities to reach a good old age may have given rise to what is sometimes called ‘a silver economy’: an economy with all kinds of new products and services, particularly aimed at the growing share of healthy and wealthy senior citizens. The greying of Europe might, thus, ultimately lead us into a bright and colourful future.
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| 5. |
- Aartsen, M. G., et al.
(författare)
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The Search For Transient Astrophysical Neutrino Emission With Icecube-Deepcore
- 2016
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 816:2
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of a search for astrophysical sources of brief transient neutrino emission using IceCube and DeepCore data acquired between 2012 May 15 and 2013 April 30. While the search methods employed in this analysis are similar to those used in previous IceCube point source searches, the data set being examined consists of a sample of predominantly sub-TeV muon-neutrinos from the Northern Sky (-5 degrees < delta < 90 degrees) obtained through a novel event selection method. This search represents a first attempt by IceCube to identify astrophysical neutrino sources in this relatively unexplored energy range. The reconstructed direction and time of arrival of neutrino events are used to search for any significant self-correlation in the data set. The data revealed no significant source of transient neutrino emission. This result has been used to construct limits at timescales ranging from roughly 1 s to 10 days for generic soft-spectra transients. We also present limits on a specific model of neutrino emission from soft jets in core-collapse supernovae.
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| 6. |
- Abbasi, R., et al.
(författare)
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Measurement of the anisotropy of cosmic-ray arrival directions with icecube
- 2010
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Ingår i: The Astrophysical Journal Letters. - 2041-8205. ; 718, s. L194-L198
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Tidskriftsartikel (refereegranskat)abstract
- We report the first observation of an anisotropy in the arrival direction of cosmic rays with energies in the multi-TeV region in the Southern sky using data from the IceCube detector. Between 2007 June and 2008 March, the partially deployed IceCube detector was operated in a configuration with 1320 digital optical sensors distributed over 22 strings at depths between 1450 and 2450 m inside the Antarctic ice. IceCube is a neutrino detector, but the data are dominated by a large background of cosmic-ray muons. Therefore, the background data are suitable for high-statistics studies of cosmic rays in the southern sky. The data include 4.3 billion muons produced by downward-going cosmic-ray interactions in the atmosphere; these events were reconstructed with a median angular resolution of 3 degrees and a median energy of similar to 20 TeV. Their arrival direction distribution exhibits an anisotropy in right ascension with a first-harmonic amplitude of (6.4 +/- 0.2 stat. +/- 0.8 syst.) x 10(-4).
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| 7. |
- Aartsen, M. G., et al.
(författare)
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SEARCH FOR TIME-INDEPENDENT NEUTRINO EMISSION FROM ASTROPHYSICAL SOURCES WITH 3 yr OF IceCube DATASearch for time-independent neutrino emission from astrophysical sources with 3 yr of icecube data
- 2013
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 779:2, s. 132-
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of a search for neutrino point sources using the IceCube data collected between 2008 April and 2011 May with three partially completed configurations of the detector: the 40-, 59-, and 79-string configurations. The live-time of this data set is 1040 days. An unbinned maximum likelihood ratio test was used to search for an excess of neutrinos above the atmospheric background at any given direction in the sky. By adding two more years of data with improved event selection and reconstruction techniques, the sensitivity was improved by a factor of 3.5 or more with respect to the previously published results obtained with the 40-string configuration of IceCube. We performed an all-sky survey and a dedicated search using a catalog of a priori selected objects observed by other telescopes. In both searches, the data are compatible with the background-only hypothesis. In the absence of evidence for a signal, we set upper limits on the flux of muon neutrinos. For an E-2 neutrino spectrum, the observed limits are (0.9-5) x 10(-12) TeV-1 cm(-2) s(-1) for energies between 1 TeV and 1 PeV in the northern sky and (0.9-23.2) x 10(-12) TeV-1 cm(-2) s(-1) for energies between 10(2) TeV and 10(2) PeV in the southern sky. We also report upper limits for neutrino emission from groups of sources that were selected according to theoretical models or observational parameters and analyzed with a stacking approach. Some of the limits presented already reach the level necessary to quantitatively test current models of neutrino emission.
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| 8. |
- Abbasi, R., et al.
(författare)
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A Search for Time-dependent Astrophysical Neutrino Emission with IceCube Data from 2012 to 2017
- 2021
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 911:1
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Tidskriftsartikel (refereegranskat)abstract
- High-energy neutrinos are unique messengers of the high-energy universe, tracing the processes of cosmic ray acceleration. This paper presents analyses focusing on time-dependent neutrino point-source searches. A scan of the whole sky, making no prior assumption about source candidates, is performed, looking for a space and time clustering of high-energy neutrinos in data collected by the IceCube Neutrino Observatory between 2012 and 2017. No statistically significant evidence for a time-dependent neutrino signal is found with this search during this period, as all results are consistent with the background expectation. Within this study period, the blazar 3C 279, showed strong variability, inducing a very prominent gamma-ray flare observed in 2015 June. This event motivated a dedicated study of the blazar, which consists of searching for a time-dependent neutrino signal correlated with the gamma-ray emission. No evidence for a time-dependent signal is found. Hence, an upper limit on the neutrino fluence is derived, allowing us to constrain a hadronic emission model.
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| 9. |
- Abbasi, R., et al.
(författare)
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IceCube Search for High-Energy Neutrinos from Ultra-Luminous Infrared Galaxies
- 2022
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Ingår i: 37th International Cosmic Ray Conference (ICRC 2021). - Trieste, Italy : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- With infrared luminosities LIR ≥ 1012L⊙, Ultra-Luminous Infrared Galaxies (ULIRGs) are the most luminous objects in the infrared sky. They are predominantly powered by starburst regions with star-formation rates ≳ 100 M⊙ yr−1. ULIRGs can also host an active galactic nucleus (AGN). Both the starburst and AGN environments contain plausible hadronic accelerators, making ULIRGs candidate neutrino sources. We present the results of an IceCube stacking analysis searching for high-energy neutrinos from a representative sample of 75 ULIRGs with redshift z ≤0.13. While no significant excess of ULIRG neutrinos is found in 7.5 years of IceCube data, upper limits are reported on the neutrino flux from these 75 ULIRGs as well as an extrapolation for the full ULIRG source population. In addition, constraints are provided on models predicting neutrino emission from ULIRGs.
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| 10. |
- Abbasi, R., et al.
(författare)
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Measurement of acoustic attenuation in South Pole ice
- 2011
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 34:6, s. 382-393
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Tidskriftsartikel (refereegranskat)abstract
- Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient alpha = 3.20 +/- 0.57 km(-1) between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for lambda equivalent to 1/alpha of similar to 300 m with 20% uncertainty. No significant depth or frequency dependence has been found.
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