Local Distance Pattern Distinguishing Sets in Graphs

2019 ◽  
pp. 517-525
Author(s):  
R. Anantha Kumar
Keyword(s):  
Local Distance

659Left atrial wall thickness evaluation during atrial fibrillation redo procedures

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
C Teres ◽  
D Soto ◽  
B Jauregui ◽  
D Penela ◽  
A Ordonez ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Wall Thickness ◽  
Atrial Wall ◽  
Ablation Procedure ◽  
Left Atrial Wall ◽  
Local Distance ◽  
The Mean ◽  
The Right ◽  
The Relationship ◽  
Funding Acknowledgements

Abstract Funding Acknowledgements Dr Teres was funded by Swiss Heartrhythm Foundation Introduction pulmonary vein (PV) reconnections due to gaps on circumferential ablation lines are responsible for atrial fibrillation recurrences after catheter ablation. We sought to analyze the local left atrial wall thickness (LAWT) of PV line gaps at AF redo ablation during real-time catheter positioning. LAWT was measured on the MDCT 3D reconstruction and fused with the LA anatomy using CARTO-merge. Objective To analyze the relationship between local reconnection gaps and the LAWT during AF redo procedures. Methods Single-Center cohort study that included 41 consecutive patients referred for AF redo procedure. All patients had a MDCT prior to the ablation procedure. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium. Each PV line was subdivided into 8 segments and mean LAWT was computed. During the procedure, the local gap was defined as the earliest activation site at the reconnected segment of the circumferential PV line (Figure 1A & 1B). Results 41 patients [31 (75.6%) male, age 60 ± 10 years] were included. Mean LAWT was 1.36 ± 0.20 mm. Mean PV circumferential line WT was higher in left PVs than in the right PVs 1.68 ± 0.57 vs. 1.31 ± 0.39 mm p < 0.001 respectively. Mean WT of the reconnected points was 44% higher than the mean WT of the segment where the reconnection was located. Mean reconnection point WT was at the 87th percentile of the circumferential line in the LPVs and at the 76th percentile in the RPVs. The reconnected point WT was higher in the LPVs than RPVs 2.13 ± 1.14 vs. 1.47 ± 0.48 mm p < 0.001 respectively.  The most frequent location for reconnections was the left anterior carina (71%), with a mean WT of 2.24 ± 0.91mm; and the right anterior carina (56%) with a mean WT of 1.57 ± 0.62mm (Figure 2A & 2B). Conclusions Reconnection points were more frequently present in the thicker segments of the PV circumferential line. The most frequently reconnected segment was the anterior carina in both right and left PVs. Atrial wall thickness maps derived from MDCT are useful to guide AF redo procedures. Abstract Figure. 1) Activation & WT map; 2) Segment WT

Local Distance Metric Adaptation

2011 ◽  
pp. 613-613
Author(s):  
Geoffrey I. Webb ◽  
Claude Sammut ◽  
Claudia Perlich ◽  
Tamás Horváth ◽  
Stefan Wrobel ◽  
...  
Keyword(s):  
Distance Metric ◽  
Local Distance

On Main Sequence Distances and the Local Distance Scale

1992 ◽  
pp. 485-485
Author(s):  
R. A. Schommer ◽  
E. W. Olszewski ◽  
M. A. Aaronson
Keyword(s):  
Main Sequence ◽  
Distance Scale ◽  
Local Distance

scholarly journals OCAAT: automated analysis of star cluster colour-magnitude diagrams for gauging the local distance scale

2014 ◽  
Vol 10 (S306) ◽  
pp. 298-300
Author(s):  
Gabriel I. Perren ◽  
Ruben A. Vázquez ◽  
Andrés E. Piatti ◽  
André Moitinho
Keyword(s):  
Main Sequence ◽  
Star Clusters ◽  
Automated Analysis ◽  
Star Cluster ◽  
Magellanic Clouds ◽  
Distance Scale ◽  
Analysis Tool ◽  
Large Set ◽  
Uncertainty Estimates ◽  
Local Distance

AbstractStar clusters are among the fundamental astrophysical objects used in setting the local distance scale. Despite its crucial importance, the accurate determination of the distances to the Magellanic Clouds (SMC/LMC) remains a fuzzy step in the cosmological distance ladder. The exquisite astrometry of the recently launched ESA Gaia mission is expected to deliver extremely accurate statistical parallaxes, and thus distances, to the SMC/LMC. However, an independent SMC/LMC distance determination via main sequence fitting of star clusters provides an important validation check point for the Gaia distances. This has been a valuable lesson learnt from the famous Hipparcos Pleiades distance discrepancy problem. Current observations will allow hundreds of LMC/SMC clusters to be analyzed in this light.Today, the most common approach for star cluster main sequence fitting is still by eye. The process is intrinsically subjective and affected by large uncertainties, especially when applied to poorly populated clusters. It is also, clearly, not an efficient route for addressing the analysis of hundreds, or thousands, of star clusters. These concerns, together with a new attitude towards advanced statistical techniques in astronomy and the availability of powerful computers, have led to the emergence of software packages designed for analyzing star cluster photometry. With a few rare exceptions, those packages are not publicly available.Here we present OCAAT (Open Cluster Automated Analysis Tool), a suite of publicly available open source tools that fully automatises cluster isochrone fitting. The code will be applied to a large set of hundreds of open clusters observed in the Washington system, located in the Milky Way and the Magellanic Clouds. This will allow us to generate an objective and homogeneous catalog of distances up to ~ 60 kpc along with its associated reddening, ages and metallicities and uncertainty estimates.

scholarly journals Manifold construction based on local distance invariance

2010 ◽  
Vol 2 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Wei-Chen Cheng ◽  
Cheng-Yuan Liou
Keyword(s):  
Local Distance ◽  
Manifold Construction

scholarly journals STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408−5354

2020 ◽  
Vol 494 (4) ◽  
pp. 6072-6102 ◽  
Author(s):  
A J Shajib ◽  
S Birrer ◽  
T Treu ◽  
A Agnello ◽  
E J Buckley-Geer ◽  
...  
Keyword(s):  
Time Delay ◽  
Hubble Space Telescope ◽  
Hubble Constant ◽  
Lens System ◽  
Microwave Background ◽  
Angular Diameter Distance ◽  
Measured Time ◽  
Local Distance ◽  
Previous Sample ◽  
The Cost

ABSTRACT We present a blind time-delay cosmographic analysis for the lens system DES J0408−5354. This system is extraordinary for the presence of two sets of multiple images at different redshifts, which provide the opportunity to obtain more information at the cost of increased modelling complexity with respect to previously analysed systems. We perform detailed modelling of the mass distribution for this lens system using three band Hubble Space Telescope imaging. We combine the measured time delays, line-of-sight central velocity dispersion of the deflector, and statistically constrained external convergence with our lens models to estimate two cosmological distances. We measure the ‘effective’ time-delay distance corresponding to the redshifts of the deflector and the lensed quasar $D_{\Delta t}^{\rm eff}=$$3382_{-115}^{+146}$ Mpc and the angular diameter distance to the deflector Dd = $1711_{-280}^{+376}$ Mpc, with covariance between the two distances. From these constraints on the cosmological distances, we infer the Hubble constant H0= $74.2_{-3.0}^{+2.7}$ km s−1 Mpc−1 assuming a flat ΛCDM cosmology and a uniform prior for Ωm as $\Omega _{\rm m} \sim \mathcal {U}(0.05, 0.5)$. This measurement gives the most precise constraint on H0 to date from a single lens. Our measurement is consistent with that obtained from the previous sample of six lenses analysed by the H0 Lenses in COSMOGRAIL’s Wellspring (H0LiCOW) collaboration. It is also consistent with measurements of H0 based on the local distance ladder, reinforcing the tension with the inference from early Universe probes, for example, with 2.2σ discrepancy from the cosmic microwave background measurement.

scholarly journals Strongly lensed SNe Ia in the era of LSST: observing cadence for lens discoveries and time-delay measurements

2019 ◽  
Vol 631 ◽  
pp. A161 ◽  
Author(s):  
S. Huber ◽  
S. H. Suyu ◽  
U. M. Noebauer ◽  
V. Bonvin ◽  
D. Rothchild ◽  
...  
Keyword(s):  
Time Delay ◽  
Percent Level ◽  
Hubble Constant ◽  
Sampling Frequency ◽  
Season Length ◽  
Delay Measurement ◽  
Type Ia ◽  
Local Distance ◽  
Ia Supernovae

The upcoming Large Synoptic Survey Telescope (LSST) will detect many strongly lensed Type Ia supernovae (LSNe Ia) for time-delay cosmography. This will provide an independent and direct way for measuring the Hubble constant H0, which is necessary to address the current 4.4σ tension in H0 between the local distance ladder and the early Universe measurements. We present a detailed analysis of different observing strategies (also referred to as cadence strategy) for the LSST, and quantify their impact on time-delay measurement between multiple images of LSNe Ia. For this, we simulated observations by using mock LSNe Ia for which we produced mock-LSST light curves that account for microlensing. Furthermore, we used the free-knot splines estimator from the software PyCS to measure the time delay from the simulated observations. We find that using only LSST data for time-delay cosmography is not ideal. Instead, we advocate using LSST as a discovery machine for LSNe Ia, enabling time delay measurements from follow-up observations from other instruments in order to increase the number of systems by a factor of 2–16 depending on the observing strategy. Furthermore, we find that LSST observing strategies, which provide a good sampling frequency (the mean inter-night gap is around two days) and high cumulative season length (ten seasons with a season length of around 170 days per season), are favored. Rolling cadences subdivide the survey and focus on different parts in different years; these observing strategies trade the number of seasons for better sampling frequency. In our investigation, this leads to half the number of systems in comparison to the best observing strategy. Therefore rolling cadences are disfavored because the gain from the increased sampling frequency cannot compensate for the shortened cumulative season length. We anticipate that the sample of lensed SNe Ia from our preferred LSST cadence strategies with rapid follow-up observations would yield an independent percent-level constraint on H0.

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