The Crab pulsar light curve in the soft gamma ray range: FIGARO II results

The FIGARO II experiment (a large area, balloon borne, crystal scintillator detector working from 0.15 to 4.3 MeV) observed the Crab pulsar on 1990 Jul. 9 for about seven hours. The study of the pulse profile confirms some structures detected with a low significance during the shorter observation of 1986, and adds new important elements to the picture. In particular, between the two main peaks, two secondary peaks appear centered at phase values 0.1 and 0.3, in the energy range 0.38 to 0.49 MeV; in the same energy range, a spectral feature at 0.44 MeV, interpreted as a redshifted positron annihilation line, was observed during the same balloon flight in the phase interval including the second main peak and the neighboring secondary peak. If the phase interval considered is extended to include also the other secondary peak, the significance of the spectral line appears to increase

High‐resolution rock magnetic cyclostratigraphy in an Eocene flysch, Spanish Pyrenees

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95346/1/ggge1746.pd

Association of follow-up infarct volume with functional outcome in acute ischemic stroke: a pooled analysis of seven randomized trials.

BACKGROUND: Follow-up infarct volume (FIV) has been recommended as an early indicator of treatment efficacy in patients with acute ischemic stroke. Questions remain about the optimal imaging approach for FIV measurement. OBJECTIVE: To examine the association of FIV with 90-day modified Rankin Scale (mRS) score and investigate its dependency on acquisition time and modality. METHODS: Data of seven trials were pooled. FIV was assessed on follow-up (12 hours to 2 weeks) CT or MRI. Infarct location was defined as laterality and involvement of the Alberta Stroke Program Early CT Score regions. Relative quality and strength of multivariable regression models of the association between FIV and functional outcome were assessed. Dependency of imaging modality and acquisition time (≤48 hours vs >48 hours) was evaluated. RESULTS: Of 1665 included patients, 83% were imaged with CT. Median FIV was 41 mL (IQR 14-120). A large FIV was associated with worse functional outcome (OR=0.88(95% CI 0.87 to 0.89) per 10 mL) in adjusted analysis. A model including FIV, location, and hemorrhage type best predicted mRS score. FIV of ≥133 mL was highly specific for unfavorable outcome. FIV was equally strongly associated with mRS score for assessment on CT and MRI, even though large differences in volume were present (48 mL (IQR 15-131) vs 22 mL (IQR 8-71), respectively). Associations of both early and late FIV assessments with outcome were similar in strength (ρ=0.60(95% CI 0.56 to 0.64) and ρ=0.55(95% CI 0.50 to 0.60), respectively). CONCLUSIONS: In patients with an acute ischemic stroke due to a proximal intracranial occlusion of the anterior circulation, FIV is a strong independent predictor of functional outcome and can be assessed before 48 hours, oneither CT or MRI

Chlorine and bromine isotope evolution within a fully developed Upper Permian natural salt sequence

The behaviour of chlorine and bromine isotopes in evaporite deposits differs significantly. We studied the isotope variations of both elements in a fully developed natural salt sequence from Zechstein evaporite deposits (Wuchiapingian, Upper Permian) in the Northern Netherlands. We observed that the Cl isotope variations follow previously predicted characteristics, showing slightly positive δ37Cl (relative to seawater) in halite (NaCl) dominated layers (up to +0.05‰), decreasing to moderately negative values in carnallite (KMgCl3·6H2O) and bischofite (MgCl2·6H2O) dominated layers (down to −0.55‰). Bromine isotope variations, the first ever measured in marine evaporite samples, show a different characteristic. δ81Br values decrease quickly in layers dominated by halite (from +0.2 to −0.5‰) and increase again in layers dominated by carnallite and bischofite (up to −0.1 ± 0.2‰). These observations suggest that the Br isotope fractionation (103lnα) during precipitation of halite can be as high as +1.3, 3.8 times as large as Cl isotope fractionation. The increasing δ81Br values during precipitation of magnesium salts may suggest a negative fractionation (103lnα) of −0.9, meaning that the Br isotope ratio in the precipitated salt is lower than in the brine. We suggest that the difference in behaviour between Cl and Br can be explained by the fact that Br, as a minor component in the brine, has to compete with Cl to fit into the crystal lattice of Cl salts, where it does not fit perfectly due to its slightly larger ionic radius than Cl, resulting in relatively large isotope fractionation. Further research is however needed to confirm or reject this suggestion