7,318 research outputs found
The East-West asymmetry of single muons at Campinas
The EASCAMP experiment, one of the few situated in the Southern Hemisphere, operating at the State University of Campinas, UNICAMP, Brazil, detected for two years single muons in the low energetic range. The primary cosmic
rays that produce these muons have a geomagnetic vertical cut-off of 10.6 GV. We studied the azimuthal distribution of three million single muons obtaining an East-West asymmetry of AEW = ( 8.91 ± 0.04)%. Another analysis concerned with the atmospheric muons propagation index is performed comparing the experimental zenith angular distribution and a simulated isotropic cosmic rays distribution
Model reduction for analysis of cascading failures in power systems
In this paper, we apply a principal-orthogonal decomposition based method to the model reduction of a hybrid, nonlinear model of a power network. The results demonstrate that the sequence of fault events can be evaluated and predicted without necessarily simulating the whole system
Fireshape: a shape optimization toolbox for Firedrake
Shape optimization studies how to design a domain such that a shape function is minimized. Ubiquitous in industrial applications, shape optimization is often constrained to partial differential equations (PDEs). One of the main challenges in PDE-constrained shape optimization is the coupling of domain updates and PDE-solvers. Fireshape addresses this challenge by elegantly coupling the finite element library Firedrake and the Rapid Optimization Library (ROL). The main features of Fireshape are: accessibility to users with minimal shape optimization knowledge; decoupled discretization of control and state variables; full access to Firedrake's PDE-solvers; automated derivation of adjoint equations and shape derivatives; different metrics to define shape gradients; access to ROL's optimization algorithms via PyROL. Fireshape is available at https://github.com/fireshape/fireshape. Fireshape's documentation comprises several tutorials and is available at https://fireshape.readthedocs.io/en/latest/
Longitudinal Assessment of Cognitive Function by Clock Drawing in Older Adults
www.karger.com/dee This is an Open Access article licensed under the terms of the Creative Commons Attribution- NonCommercial-NoDerivs 3.0 License (www.karger.com/OA-license), applicable to the online version of the article only. Distribution for non-commercial purposes only
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Cerebral Microbleeds in a Stroke Prevention Clinic.
The objective of this study is to assess the effectiveness of a stroke clinic in stroke prevention and progression of cerebral microbleeds (CMB). We conducted a retrospective observational study of patients who visited a stroke clinic between January 2011 and March 2017. Susceptibility-weighted imaging (SWI) MRI studies were obtained at baseline and follow-up visits to identify new infarctions and CMB progression. Patients with CMB who also underwent brain computed tomography (CT) imaging were identified and their cerebral arterial calcification was quantified to evaluate the relationship between the extent of intracranial calcification and CMB burden. A total of 64 stroke patients (mean age 73.1 ± 11.0, 47% males) had CMB on baseline and follow-up MRI studies. During a mean follow-up period of 22.6 months, four strokes occurred (4/64, 6%; 3 ischemic, 1 hemorrhagic), producing mild neurological deficit. Progression of CMB was observed in 54% of patients with two MRIs and was significantly associated with length of follow-up. Subjects with intracranial calcification score > 300 cm3 had higher CMB count than those with scores <300 cm3 at both baseline (12.6 ± 11.7 vs. 4.9 ± 2.2, p = 0.02) and follow-up (14.1 ± 11.8 vs. 5.6 ± 2.4, p = 0.03) MRI evaluations. Patients with CMB had a relatively benign overall clinical course. The association between CMB burden and intracranial calcification warrants further study
A Measurement of Water Vapour amid a Largely Quiescent Environment on Europa
Previous investigations proved the existence of local density enhancements in Europas atmosphere, advancing the idea of a possible origination from water plumes. These measurement strategies, however, were sensitive either to total absorption or atomic emissions, which limited the ability to assess the water content. Here we present direct searches for water vapour on Europa spanning dates from February 2016 to May 2017 with the Keck Observatory. Our global survey at infrared wavelengths resulted in non-detections on 16 out of 17 dates, with upper limits below the water abundances inferred from previous estimates. On one date (26 April 2016) we measured 2,095 658 tonnes of water vapour at Europas leading hemisphere. We suggest that the outgassing ls than previously estimated, with only rare localized events of stronger activity
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