| 1. |
- Steinicke, Robert, et al.
(författare)
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Kidney Function and White Matter Disease in Young Stroke Patients Analysis of the Stroke in Young Fabry Patients Study Population
- 2012
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Ingår i: Stroke: a journal of cerebral circulation. - 1524-4628. ; 43:9, s. 2382-2388
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose-Impaired kidney function is thought to be associated with small vessel disease, outcome, and mortality in the general stroke population. Data are limited regarding young patients. The aim of this study was to investigate the association of kidney function and white matter hyperintensities (WMHs) in young patients with first ischemic stroke. Methods-We analyzed 2500 young (18-55 years) patients with first-ever ischemic stroke from the prospective observational Stroke in Young Fabry Patients (SIFAP1) study with available MRI data on WMH. Of these, 2009 had available data concerning estimated glomerular filtration rate (eGFR). Kidney function was expressed as eGFR by the Modification of Diet in Renal Disease method. Deep WMHs on MRI were classified by the Fazekas score. Multivariate analysis was performed using a regression model with random effects. Results-Mean eGFR was 96.7 mL/min in those with WMH Grade 0 to 1 (none to mild), 90.7 mL/min in WMH Grade 2 (moderate), and 89 mL/min in WMH Grade 3 (severe). Univariate analysis revealed WMH to be associated with age (P<0.001), hypertension (P<0.001), cardiovascular disease (P=0.015), overweight (body mass index >25 kg/m(2); P=0.013), current smoking (P=0.044), and eGFR (P=0.009). In multivariate analysis, age, hypertension, and eGFR remained associated with WMH severity. Conclusions-In young patients with acute ischemic stroke, lower eGFR values in the normal range are associated with the presence of moderate to severe WMH.
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| 2. |
- Milisavljevic, Dan, et al.
(författare)
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MULTI-WAVELENGTH OBSERVATIONS OF SUPERNOVA 2011ei : TIME-DEPENDENT CLASSIFICATION OF TYPE IIb AND Ib SUPERNOVAE AND IMPLICATIONS FOR THEIR PROGENITORS
- 2013
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 767:1, s. 71-
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Tidskriftsartikel (refereegranskat)abstract
- We present X-ray, UV/optical, and radio observations of the stripped-envelope, core-collapse supernova (SN) 2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within similar to 1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogen Balmer profiles that subside rapidly and are replaced by Type Ib-like He-rich features on a timescale of one week. High-cadence monitoring of this transition suggests absorption attributable to a high-velocity (greater than or similar to 12,000 km s(-1)) H-rich shell, which is likely present in many Type Ib events. Radio observations imply a shock velocity of v approximate to 0.13 c and a progenitor star average mass-loss rate of (M) over dot approximate to 1.4 x 10(-5) M-circle dot yr(-1) (assuming wind velocity v(w) = 10(3) km s(-1)). This is consistent with independent constraints from deep X-ray observations with Swift-XRT and Chandra. Overall, the multi-wavelength properties of SN 2011ei are consistent with the explosion of a lower-mass (3-4 M-circle dot), compact (R-* less than or similar to 1 x 10(11) cm), He-core star. The star retained a thin hydrogen envelope at the time of explosion, and was embedded in an inhomogeneous circumstellar wind suggestive of modest episodic mass loss. We conclude that SN 2011ei's rapid spectral metamorphosis is indicative of time-dependent classifications that bias estimates of the relative explosion rates for Type IIb and Ib objects, and that important information about a progenitor star's evolutionary state and mass loss immediately prior to SN explosion can be inferred from timely multi-wavelength observations.
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| 3. |
- Schulte, Peter, et al.
(författare)
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Cretaceous Extinctions: Evidence Overlooked Response
- 2010
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 328:5981, s. 975-976
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Schulte, Peter, et al.
(författare)
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The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary
- 2010
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 327:5970, s. 1214-1218
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Tidskriftsartikel (refereegranskat)abstract
- The Cretaceous-Paleogene boundary similar to 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.
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