| 1. |
- Berger, E., et al.
(författare)
-
An Intermediate Luminosity Transient in NGC 300 : The Eruption of a Dust-Enshrouded Massive Star
- 2009
-
Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 699, s. 1850-1865
-
Tidskriftsartikel (refereegranskat)abstract
- We present multi-epoch high-resolution optical spectroscopy, UV/radio/X-ray imaging, and archival Hubble and Spitzer observations of an intermediate luminosity optical transient recently discovered in the nearby galaxy NGC 300. We find that the transient (NGC 300 OT2008-1) has a peak absolute magnitude of M bol ≈ -11.8 mag, intermediate between novae and supernovae, and similar to the recent events M85 OT2006-1 and SN 2008S. Our high-resolution spectra, the first for this event, are dominated by intermediate velocity (~200-1000 km s-1) hydrogen Balmer lines and Ca II emission and absorption lines that point to a complex circumstellar environment, reminiscent of the yellow hypergiant IRC+10420. In particular, we detect asymmetric Ca II H&K absorption with a broad red wing extending to ~103 km s-1, indicative of gas inflow at high velocity (possibly the wind of a massive binary companion). The low luminosity, intermediate velocities, and overall similarity to a known eruptive star indicate that the event did not result in a complete disruption of the progenitor. We identify the progenitor in archival Spitzer observations, with deep upper limits from Hubble data. The spectral energy distribution points to a dust-enshrouded star with a luminosity of about 6 × 104 L sun, indicative of a ~10-20 M sun progenitor (or binary system). This conclusion is in good agreement with our interpretation of the outburst and circumstellar properties. The lack of significant extinction in the transient spectrum indicates that the dust surrounding the progenitor was cleared by the outburst. We thus predict that the progenitor should be eventually visible with Hubble if the transient event marks an evolutionary transition to a dust-free state, or with Spitzer if the event marks a cyclical process of dust formation.
|
|
| 2. |
- Diamond, Merle, et al.
(författare)
-
Topiramate improves health-related quality of life when used to prevent migraine
- 2005
-
Ingår i: Headache. ; 45:8, s. 1023-30
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess changes in health-related quality of life (HRQoL) measures among patients receiving topiramate (TPM) 100 mg/d in two divided doses for migraine prevention in three randomized, double-blind, placebo-controlled, 26-week trials with similar protocols and study populations. BACKGROUND: Migraine substantially impairs HRQoL and work productivity before, during, and after attacks. Approximately 50% of patients with migraine could be recommended for preventive therapies, yet only 3% to 5% of patients receive them. TPM is an effective and generally well-tolerated migraine prophylactic (preventive) therapy for adults, as demonstrated in several randomized, double-blind, placebo-controlled trials. The most common adverse events in double-blind, placebo-controlled studies of TPM in migraine prevention are paresthesia, fatigue, anorexia, nausea, taste alteration, and diarrhea. DESIGN AND METHODS: The Migraine-Specific Questionnaire (MSQ, version 2.1) was used to assess the effect of TPM 100 mg/d on the functionality and HRQoL of randomized intent-to-treat (ITT) and study-completer populations pooled from three randomized, double-blind, placebo-controlled trials. MSQ scores (0 to 100, higher score indicates better functioning) were assessed for the following three domains: role restriction (examines the degree to which performance of daily activities is limited by migraine), role prevention (examines the degree to which performance of daily activities is interrupted by migraine), and emotional function (examines feelings of frustration and helplessness due to migraine). Between-group differences from baseline in mean MSQ domain scores for TPM 100 mg/d and placebo were compared using a mixed-effects model with piecewise linear regression. Effect sizes were calculated to estimate the magnitude of change in HRQoL that can be associated with TPM therapy. RESULTS: TPM 100 mg/d significantly improved all three MSQ domains compared with placebo for both the ITT (TPM, n = 372; placebo, n = 362) and study-completer (TPM, n = 220; placebo, n = 216) populations (P < .001 for all three domains, both populations). Effect sizes for TPM 100 mg/d varied from 0.40 to 0.78, indicating that the changes in MSQ scores for TPM 100 mg/d were moderate and may be clinically significant. CONCLUSION: TPM 100 mg/d has been shown to be effective in the prevention of migraine headache in adults. As the MSQ results from the three randomized, placebo-controlled trials indicate, HRQoL is significantly improved for up to 6 months following initiation of treatment.
|
|
