| 61. |
- Aartsen, M. G., et al.
(författare)
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South Pole glacial climate reconstruction from multi-borehole laser particulate stratigraphy
- 2013
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Ingår i: Journal of Glaciology. - 0022-1430 .- 1727-5652. ; 59:218, s. 1117-1128
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Tidskriftsartikel (refereegranskat)abstract
- The IceCube Neutrino Observatory and its prototype, AMANDA, were built in South Pole ice, using powerful hot-water drills to cleanly bore >100 holes to depths up to 2500 m. The construction of these particle physics detectors provided a unique opportunity to examine the deep ice sheet using a variety of novel techniques. We made high-resolution particulate profiles with a laser dust logger in eight of the boreholes during detector commissioning between 2004 and 2010. The South Pole laser logs are among the most clearly resolved measurements of Antarctic dust strata during the last glacial period and can be used to reconstruct paleoclimate records in exceptional detail. Here we use manual and algorithmic matching to synthesize our South Pole measurements with ice-core and logging data from Dome C, East Antarctica. We derive impurity concentration, precision chronology, annual-layer thickness, local spatial variability, and identify several widespread volcanic ash depositions useful for dating. We also examine the interval around similar to 74 ka recently isolated with radiometric dating to bracket the Toba (Sumatra) supereruption.
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| 62. |
- Aartsen, M. G., et al.
(författare)
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The IceProd framework : Distributed data processing for the IceCube neutrino observatory
- 2015
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Ingår i: Journal of Parallel and Distributed Computing. - : Elsevier BV. - 0743-7315 .- 1096-0848. ; 75, s. 198-211
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Tidskriftsartikel (refereegranskat)abstract
- IceCube is a one-gigaton instrument located at the geographic South Pole, designed to detect cosmic neutrinos, identify the particle nature of dark matter, and study high-energy neutrinos themselves. Simulation of the IceCube detector and processing of data require a significant amount of computational resources. This paper presents the first detailed description of IceProd, a lightweight distributed management system designed to meet these requirements. It is driven by a central database in order to manage mass production of simulations and analysis of data produced by the IceCube detector. IceProd runs as a separate layer on top of other middleware and can take advantage of a variety of computing resources, including grids and batch systems such as CREAM, HTCondor, and PBS. This is accomplished by a set of dedicated daemons that process job submission in a coordinated fashion through the use of middleware plugins that serve to abstract the details of job submission and job management from the framework. (C) 2014 Elsevier Inc. All rights reserved.
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| 63. |
- 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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| 64. |
- 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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| 65. |
- Abdulle, Assyr, et al.
(författare)
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High weak order methods for stochastic differential equations based on modified equations
- 2012
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Ingår i: SIAM Journal on Scientific Computing. - : Society for Industrial & Applied Mathematics (SIAM). - 1064-8275 .- 1095-7197. ; 34:3, s. A1800-A1823
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by recent advances in the theory of modified differential equations, we propose a new methodology for constructing numerical integrators with high weak order for the time integration of stochastic differential equations. This approach is illustrated with the constructions of new methods of weak order two, in particular, semi-implicit integrators well suited for stiff (mean-square stable) stochastic problems, and implicit integrators that exactly conserve all quadratic firstintegrals of a stochastic dynamical system. Numerical examples confirm the theoretical results and show the versatility of our methodology.
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| 66. |
- Abolfathi, Bela, et al.
(författare)
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The LSST DESC DC2 Simulated Sky Survey
- 2021
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 253:31
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Tidskriftsartikel (refereegranskat)abstract
- We describe the simulated sky survey underlying the second data challenge (DC2) carried out in preparation for analysis of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) by the LSST Dark Energy Science Collaboration (LSST DESC). Significant connections across multiple science domains will be a hallmark of LSST; the DC2 program represents a unique modeling effort that stresses this interconnectivity in a way that has not been attempted before. This effort encompasses a full end-to-end approach: starting from a large N-body simulation, through setting up LSST-like observations including realistic cadences, through image simulations, and finally processing with Rubin's LSST Science Pipelines. This last step ensures that we generate data products resembling those to be delivered by the Rubin Observatory as closely as is currently possible. The simulated DC2 sky survey covers six optical bands in a wide-fast-deep area of approximately 300 deg2, as well as a deep drilling field of approximately 1 deg2. We simulate 5 yr of the planned 10 yr survey. The DC2 sky survey has multiple purposes. First, the LSST DESC working groups can use the data set to develop a range of DESC analysis pipelines to prepare for the advent of actual data. Second, it serves as a realistic test bed for the image processing software under development for LSST by the Rubin Observatory. In particular, simulated data provide a controlled way to investigate certain image-level systematic effects. Finally, the DC2 sky survey enables the exploration of new scientific ideas in both static and time domain cosmology.
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| 67. |
- Abu-Much, Arsalan, et al.
(författare)
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Influence of Left Ventricular Ejection Fraction in Patients Undergoing Contemporary pLVAD-Supported High-Risk PCI.
- 2023
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Ingår i: American heart journal. - 1097-6744.
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Tidskriftsartikel (refereegranskat)abstract
- Left ventricular (LV) systolic dysfunction worsens outcomes in patients undergoing percutaneous coronary intervention (PCI). The objective of this study, therefore, was to evaluate outcomes of pLVAD-supported high-risk PCI (HRPCI) patients according to LV ejection fraction (LVEF).Patients from the PROTECT III study undergoing pLVAD-supported HRPCI were stratified according to baseline LVEF: severe LV dysfunction (LVEF<30%), mild and moderate LV dysfunction (LVEF ≥30% to <50%), or preserved LV function (LVEF≥50%). Major adverse cardiovascular and cerebrovascular events (MACCE: composite of all-cause death, myocardial infarction, stroke/transient ischemic attack, and repeat revascularization), and PCI-related complications were assessed at 90 days and mortality was assessed at 1-year.From March 2017 to March 2020, 940 patients had evaluable baseline LVEF recorded in the study database. Patients with preserved LV function were older, more frequently presented with myocardial infarction, and underwent more left main PCI and atherectomy. Immediate PCI-related coronary complications were infrequent (2.7%, overall), similar between groups (p=0.98), and not associated with LVEF. Unadjusted 90-day MACCE rates were similar among LVEF groups; however, as a continuous variable, LVEF was associated with both 90-day MACCE (adj.HR per 5% 0.89, 95% CI [0.80, 0.98], p=0.018) and 1-year mortality (adj.HR per 5% 0.84 [0.78, 0.90], p<0.0001).Patients who underwent pLVAD-supported HRPCI exhibited low incidence of PCI-related complications, regardless of baseline LVEF. However, LVEF was associated with 90-day MACCE and 1-year mortality.
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| 68. |
- Ackermann, M., et al.
(författare)
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THE FIRST FERMI-LAT CATALOG OF SOURCES ABOVE 10 GeV
- 2013
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 209:2
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Tidskriftsartikel (refereegranskat)abstract
- We present a catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first 3 yr of the Fermi Gamma-ray Space Telescope mission. The first Fermi catalog of > 10 GeV sources (1FHL) has 514 sources. For each source we present location, spectrum, a measure of variability, and associations with cataloged sources at other wavelengths. We found that 449 (87%) could be associated with known sources, of which 393 (76% of the 1FHL sources) are active galactic nuclei. Of the 27 sources associated with known pulsars, we find 20 (12) to have significant pulsations in the range > 10 GeV (> 25 GeV). In this work we also report that, at energies above 10 GeV, unresolved sources account for 27% +/- 8% of the isotropic. gamma-ray background, while the unresolved Galactic population contributes only at the few percent level to the Galactic diffuse background. We also highlight the subset of the 1FHL sources that are best candidates for detection at energies above 50-100 GeV with current and future ground-based gamma-ray observatories.
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| 69. |
- Agnelli, G, et al.
(författare)
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Safety assessment of new antithrombotic agents : Lessons from the EXTEND study on ximelagatran.
- 2009
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 123:3, s. 488-497
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Ximelagatran, the first oral direct thrombin inhibitor, was shown to be an effective antithrombotic agent but was associated with potential liver toxicity after prolonged administration. OBJECTIVES AND METHODS: The aim of the EXTEND study was to assess safety and efficacy of extended administration (35 days) of ximelagatran or enoxaparin for the prevention of venous thromboembolism after elective hip replacement and hip fracture surgery. A follow-up period, including assessment of liver enzymes (in particular alanine aminotransferase; ALAT), until post-operative day 180 was planned, with visits at days 56 and 180. RESULTS: Randomization and administration of study drugs were stopped following a report of serious liver injury occurring 3 weeks after completion of ximelagatran treatment. At the time of study termination, 1158 patients had been randomized and 641 had completed the 35-day treatment; with 303 ximelagatran and 265 enoxaparin patients remaining in the study through to the day 56 follow-up visit. Overall, 58 patients showed an ALAT increase to >2x upper limit of normal: 31 treated with enoxaparin, 27 with ximelagatran. Three ximelagatran patients also showed symptoms potentially related to liver toxicity. Eleven ximelagatran patients showed an ALAT increase after study treatment ended. The clinical development of ximelagatran was terminated and the drug withdrawn from the market. Evaluation of the relative efficacy of the two treatments as specified in the protocol was impossible due to the premature termination of the study. CONCLUSIONS: Prolonged administration of ximelagatran was associated with an increased risk of liver toxicity. In a substantial proportion of patients, ALAT increase occurred after treatment withdrawal. The findings seen with ximelagatran should be considered when designing studies with new antithrombotic agents.
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| 70. |
- Anand-Ivell, Ravinder, et al.
(författare)
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Amniotic fluid INSL3 measured during the critical time window in human pregnancy relates to cryptorchidism, hypospadias, and phthalate load : A large case-control study
- 2018
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 9:APR
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Tidskriftsartikel (refereegranskat)abstract
- The period of the first to second trimester transition in human pregnancy represents a sensitive window for fetal organogenesis, particularly in regard to the development of the male reproductive system. This is a time of relative analytical inaccessibility. We have used a large national biobank of amniotic fluid samples collected at routine amniocentesis to determine the impacts of exogenous endocrine disruptor load on specific fetal biomarkers at this critical time. While adrenal and testicular steroids are highly correlated, they are also mostly positively influenced by increasing phthalate load, represented by the metabolites 7cx-MMeHP and 5cx-MEPP, by perfluorooctane sulfonate (PFOS) exposure, and by smoking, suggesting an adrenal stress response. In contrast, the testis specific biomarkers insulin-like peptide 3 (INSL3) and androstenedione are negatively impacted by the phthalate endocrine disruptors. Using a case-control design, we show that cryptorchidism and hypospadias are both significantly associated with increased amniotic concentration of INSL3 during gestational weeks 13-16, and some, though not all steroid biomarkers. Cases are also linked to a specifically increased variance in the Leydig cell biomarker INSL3 compared to controls, an effect exacerbated by maternal smoking. No influence of phthalate metabolites or PFOS was evident on the distribution of cases and controls. Considering that several animal and human studies have shown a negative impact of phthalate load on fetal and cord blood INSL3, respectively, the present results suggest that such endocrine disruptors may rather be altering the relative dynamics of testicular development and consequent hormone production, leading to a desynchronization of tissue organization during fetal development. Being born small for gestational age appears not to impact on the testicular biomarker INSL3 in second trimester amniotic fluid.
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