| 1. |
- Achterberg, A., et al.
(author)
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The search for muon neutrinos from northern hemisphere gamma-ray bursts with AMANDA
- 2008
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 674:1, s. 357-370
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Journal article (peer-reviewed)abstract
- We present the results of the analysis of neutrino observations by the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated with photon observations of more than 400 gamma-ray bursts (GRBs) in the northern hemisphere from 1997 to 2003. During this time period, AMANDA's effective collection area for muon neutrinos was larger than that of any other existing detector. After the application of various selection criteria to our data, we expect similar to 1 neutrino event and <2 background events. Based on our observations of zero events during and immediately prior to the GRBs in the data set, we set the most stringent upper limit on muon neutrino emission correlated with GRBs. Assuming a Waxman-Bahcall spectrum and incorporating all systematic uncertainties, our flux upper limit has a normalization at 1 PeV of E-2 Phi(nu) <= 6.3 x 10(-9) GeV cm(-2) s(-1) sr(-1), with 90% of the events expected within the energy range of similar to 10 TeV to similar to 3 PeV. The impact of this limit on several theoretical models of GRBs is discussed, as well as the future potential for detection of GRBs by next-generation neutrino telescopes. Finally, we briefly describe several modifications to this analysis in order to apply it to other types of transient point sources.
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| 2. |
- Abdo, A. A., et al.
(author)
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FERMI OBSERVATIONS OF GRB 090902B : A DISTINCT SPECTRAL COMPONENT IN THE PROMPT AND DELAYED EMISSION
- 2009
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In: Astrophysical Journal Letters. - 2041-8205 .- 0004-637X .- 1538-4357. ; 706:1, s. L138-L144
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Journal article (peer-reviewed)abstract
- We report on the observation of the bright, long gamma-ray burst (GRB), GRB 090902B, by the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) instruments on-board the Fermi observatory. This was one of the brightest GRBs to have been observed by the LAT, which detected several hundred photons during the prompt phase. With a redshift of z = 1.822, this burst is among the most luminous detected by Fermi. Time-resolved spectral analysis reveals a significant power-law component in the LAT data that is distinct from the usual Band model emission that is seen in the sub-MeV energy range. This power-law component appears to extrapolate from the GeV range to the lowest energies and is more intense than the Band component, both below similar to 50 keV and above 100 MeV. The Band component undergoes substantial spectral evolution over the entire course of the burst, while the photon index of the power-law component remains constant for most of the prompt phase, then hardens significantly toward the end. After the prompt phase, power-law emission persists in the LAT data as late as 1 ks post-trigger, with its flux declining as t(-1.5). The LAT detected a photon with the highest energy so far measured from a GRB, 33.4(-3.5)(+ 2.7) GeV. This event arrived 82 s after the GBM trigger and similar to 50 s after the prompt phase emission had ended in the GBM band. We discuss the implications of these results for models of GRB emission and for constraints on models of the extragalactic background light.
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| 3. |
- Armesto, N., et al.
(author)
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Heavy-ion collisions at the LHC-Last call for predictions
- 2008
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In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 35:5, s. 054001-
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Research review (peer-reviewed)abstract
- This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from 14th May to 10th June 2007.
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| 4. |
- Dietzek, Benjamin, et al.
(author)
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Excited-state dynamics of Ru(tbbpy)(3)(2+) investigated by femtosecond time-resolved four-wave mixing
- 2007
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In: Laser Physics Letters. - : IOP Publishing. - 1612-2011 .- 1612-202X. ; 4:2, s. 121-125
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Journal article (peer-reviewed)abstract
- Femtosecond time-resolved two-color four-wave mixing is employed to study the ultrafast excited-state relaxation processes in Ru(tbbpy)(3)(+2). The relaxation processes leading to a long-lived thermalized (MLCT)-M-3-state are found to take place on two distinct time-scales. An ultrafast process, which is attributed to intersystem crossing, rapidly depopulating the initially photoexcited (MLCT)-M-1-state, is found to take place in less than 200 fs. The second process visible in the experimental data occurs on a picosecond time-scale and is assigned to cooling within the (MLCT)-M-3-state.
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| 5. |
- Schlaepfer, T E, et al.
(author)
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Vagus nerve stimulation for depression: Efficacy and safety in a European study.
- 2008
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In: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 38:5, s. 651-661
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Journal article (peer-reviewed)abstract
- Background: Vagus nerve stimulation (VNS) therapy is associated with a decrease in seizure frequency in partial-onset seizure patients. Initial trials suggest that it may be an effective treatment, with few side-effects, for intractable depression. Method: An open, uncontrolled European multi-centre study (D03) of VNS therapy was conducted, in addition to stable pharmacotherapy, in 74 patients with treatment-resistant depression (TRD). Treatment remained unchanged for the first 3 months; in the subsequent 9 months, medications and VNS dosing parameters were altered as indicated clinically. Results: The baseline 28-item Hamilton Depression Rating Scale (HAMD-28) score averaged 34. After 3 months of VNS, response rates (≥50% reduction in baseline scores) reached 37% and remission rates (HAMD-28 score <10) 17%. Response rates increased to 53% after 1 year of VNS, and remission rates reached 33%. Response was defined as sustained if no relapse occurred during the first year of VNS after response onset; 44% of patients met these criteria. Median time to response was 9 months. Most frequent side-effects were voice alteration (63% at 3 months of stimulation) and coughing (23%). Conclusions: VNS therapy was effective in reducing severity of depression; efficacy increased over time. Efficacy ratings were in the same range as those previously reported from a USA study using a similar protocol; at 12 months, reduction of symptom severity was significantly higher in the European sample. This might be explained by a small but significant difference in the baseline HAMD-28 score and the lower number of treatments in the current episode in the European study.
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