18 research outputs found
Multiscale Edge Detection in the Corona
Coronal Mass Ejections (CMEs) are challenging objects to detect using
automated techniques, due to their high velocity and diffuse, irregular
morphology. A necessary step to automating the detection process is to first
remove the subjectivity introduced by the observer used in the current,
standard, CME detection and tracking method. Here we describe and demonstrate a
multiscale edge detection technique that addresses this step and could serve as
one part of an automated CME detection system. This method provides a way to
objectively define a CME front with associated error estimates. These fronts
can then be used to extract CME morphology and kinematics. We apply this
technique to a CME observed on 18 April 2000 by the Large Angle Solar
COronagraph experiment (LASCO) C2/C3 and a CME observed on 21 April 2002 by
LASCO C2/C3 and the Transition Region and Coronal Explorer (TRACE). For the two
examples in this work, the heights determined by the standard manual method are
larger than those determined with the multiscale method by approximately 10%
using LASCO data and approximately 20% using TRACE data.Comment: 14 pages, 7 figures, In Solar Physics Topical Issue "Solar Image
Analysis and Visualization
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele