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Abstract History of syncope is an independent predictor for sudden cardiac death. Programmed stimulation may be considered for risk stratification, but data remain sparse among different populations. Here, we analyzed the prognostic value of inducible ventricular arrhythmia (VA) regarding clinical outcome in patients with syncope undergoing defibrillator implantation. Among 4196 patients enrolled in the prospective, multi-center German Device Registry, patients with syncope and inducible VA (n = 285, 6.8%) vs. those with a secondary preventive indication (n = 1885, 45.2%), defined as previously documented sustained ventricular tachycardia or ventricular fibrillation, serving as a control group were studied regarding demographics, device implantation and post-procedural adverse events. Patients with syncope and inducible VA (64.9 ± 14.4 years, 81.1% male) presented less frequently with congestive heart failure (15.1% vs. 29.1%; p

Background Ultra-high-density mapping enables detailed mechanistic analysis of atrial reentrant tachycardia but has yet to be used to assess circuit conduction velocity (CV) patterns in adults with congenital heart disease. Methods and Results Circuit pathways and central isthmus CVs were calculated from consecutive ultra-high-density isochronal maps at 2 tertiary centers over a 3-year period. Circuits using anatomic versus surgical obstacles were considered separately and pathway length 85% predicted isthmus block in all cases. Over >1 year of follow-up, arrhythmia-free survival was better for homogeneous CV patterns (90% versus 57%; P=0.04). Conclusions Ultra-high-density mapping-guided CV analysis distinguishes atrial reentrant patterns in adults with congenital heart disease with surgical obstacles producing slower and smaller circuits. Very slow central isthmus CV may be essential for atrial tachycardia maintenance in small circuits, and non-isthmus conduction time in tachycardia appears to be useful for rapid assessment of postablation conduction block.

Meaningful Instruction Design (MID) merupakan model pembelajaran yang mengutamakan kebermaknaan bagi siswa agar memudahkan siswa dalam mengingat kembali materi yang telah dipelajari. Alasan dilakukan penelitian ini dikarenakan studi pendahuluan yang mengatakan bahwa pembelajaran matematika masih disajikan secara abstrak, serta dengan model yang konvensional sehingga terkesan membosankan, serta kesulitan guru dalam menjelaskan materi matematika terutama pada materi pecahan. Hal ini tentunya berdampak pada perolehan hasil belajar. Maka dari itu, diperlukan pendekatan Realistic Mathematics Education (RME) berbasis kehidupan nyata yang akan memudahkan dalam menjelaskan pembelajaran matematika. Penelitian ini bertujuan untuk melihat pengaruh model MID dengan pendekatan RME terhadap hasil belajar matematika siswa. Penelitian ini menggunakan jenis praeksperimen dengan desain pretes dan postes satu grup. Teknik pengambilan sampel seacra bertujuan sebanyak 20 sampel dari total populasi sebanyak 23 siswa. Dari hasil perhitungan, rata-rata pretest dan postes siswa yaitu sebesar 22,762 yang memiliki kenaikan hasil belajar yang signifkan. Kemudian dari signifikansi yang diperoleh yaitu 0,00 < 0,05 dengan t hitung sebesar 9,316 > 2,086 (t tabel), sehingga dapat disimpulkan bahwa model MID dengan pendekatan RME memiliki pengaruh positif dalam peningkatkan hasil belajar matematika siswa materi pecahan.

The present article analyzes the comparative characteristics of the recreational potential of hydro areas of the Republic of Kazakhstan. 20 hydro areas were marked out for comparative assessment of their attractiveness and recreational possibilities of the development of medical health tourism on the basis of balneological resources. The aim of the study is to identify the areas with the high natural recreational potential, but with a low level of exploration, thus identifying the most promising areas for the development of medical health tourism. The article gives comparative characteristics of areas with health-improving resources and the level of their development to achieve this goal. The outline maps of natural and socio-economic and recreational resources of Kazakhstan and zoning were made for the purpose of comparison of the recreational potential areas on the basis on the performed analyses. As a result, the hydro mineral regions of Kazakhstan were classified into 4 groups with very high, high, medium and low-recreational potential. The presented results of the study will help to formulate proposals for the development of specific areas with a high medical-health potential.

Abstract The World Magnetic Model (WMM) is a geomagnetic main field model that is widely used for navigation by governments, industry and the general public. In recent years, the model has been derived using high accuracy magnetometer data from the Swarm mission. This study explores the possibility of developing future WMMs in the post-Swarm era using data from the Iridium satellite constellation. Iridium magnetometers are primarily used for attitude control, so they are not designed to produce the same level of accuracy as magnetic data from scientific missions. Iridium magnetometer errors range from 30 nT quantization to hundreds of nT errors due to spacecraft contamination and calibration uncertainty, whereas Swarm measurements are accurate to about 1 nT. The calibration uncertainty in the Iridium measurements is identified as a major error source, and a method is developed to calibrate the spacecraft measurements using data from a subset of the INTERMAGNET observatory network producing quasi-definitive data on a regular basis. After calibration, the Iridium data produced main field models with approximately 20 nT average error and 40 nT maximum error as compared to the CHAOS-7.2 model. For many scientific and precision navigation applications, highly accurate Swarm-like measurements are still necessary, however, the Iridium-based models were shown to meet the WMM error tolerances, indicating that Iridium is a viable data source for future WMMs. Graphical Abstract

Background: Optimal lesion formation during catheter-based radiofrequency current (RFC) ablation depends on electro-mechanical tip-tissue coupling measurable via contact force (CF) and local impedance (LI) monitoring. We aimed to investigate CF and LI dynamics in patients with previous atrial fibrillation (AF) ablation who frequently present with heterogenous arrhythmia substrate.Methods: Data from consecutive patients presenting for repeat AF or atrial tachycardia ablation using a novel open-irrigated single-tip ablation catheter were studied. RFC applications were investigated regarding CF, LI and the maximum LI drop (∆LI) for evaluation of ablation efficacy. ∆LI > 20 Ω was defined as a successful RFC application.Results: A total of 730 RFC applications in 20 patients were analyzed. Baseline CF was not associated with baseline LI (R = 0.06, p = 0.17). A mean CF < 8 g during ablation resulted in lower ∆LI ( 20 Ω (area under the receiver operating characteristic curve (AUC) 0.75) better compared to baseline LI (AUC 0.72), mean CF (AUC 0.60), force-time integral (AUC 0.59) and local bipolar voltage (0.55).Conclusion: Combination of CF and LI may aid monitoring real-time catheter-tissue electro-mechanical coupling and lesion formation within heterogenous atrial arrhythmia substrate in patients with repeat AF or atrial tachycardia ablation.

Abstract In December 2019, the 13th revision of the International Geomagnetic Reference Field (IGRF) was released by the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group V-MOD. This revision comprises two new spherical harmonic main field models for epochs 2015.0 (DGRF-2015) and 2020.0 (IGRF-2020) and a model of the predicted secular variation for the interval 2020.0 to 2025.0 (SV-2020-2025). The models were produced from candidates submitted by fifteen international teams. These teams were led by the British Geological Survey (UK), China Earthquake Administration (China), Universidad Complutense de Madrid (Spain), University of Colorado Boulder (USA), Technical University of Denmark (Denmark), GFZ German Research Centre for Geosciences (Germany), Institut de physique du globe de Paris (France), Institut des Sciences de la Terre (France), Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (Russia), Kyoto University (Japan), University of Leeds (UK), Max Planck Institute for Solar System Research (Germany), NASA Goddard Space Flight Center (USA), University of Potsdam (Germany), and Université de Strasbourg (France). The candidate models were evaluated individually and compared to all other candidates as well to the mean, median and a robust Huber-weighted model of all candidates. These analyses were used to identify, for example, the variation between the Gauss coefficients or the geographical regions where the candidate models strongly differed. The majority of candidates were sufficiently close that the differences can be explained primarily by individual modeling methodologies and data selection strategies. None of the candidates were so different as to warrant their exclusion from the final IGRF-13. The IAGA V-MOD task force thus voted for two approaches: the median of the Gauss coefficients of the candidates for the DGRF-2015 and IGRF-2020 models and the robust Huber-weighted model for the predictive SV-2020-2025. In this paper, we document the evaluation of the candidate models and provide details of the approach used to derive the final IGRF-13 products. We also perform a retrospective analysis of the IGRF-12 SV candidates over their performance period (2015–2020). Our findings suggest that forecasting secular variation can benefit from combining physics-based core modeling with satellite observations.

Abstract The International Geomagnetic Reference Field (IGRF) is a set of parameters representing the large-scale internal part of Earth’s magnetic field. The 13th generation IGRF requested candidate models for a definitive main field for 2015.0, a provisional main field for 2020.0, and a predictive secular variation covering the period 2020.0–2025.0. The University of Colorado (CU) and the National Centers for Environmental Information (NCEI), part of the National Oceanic and Atmospheric Administration (NOAA), have produced these three candidate models for consideration in IGRF-13. In this paper, we present the methodology used to derive our candidate models. Our candidates were built primarily from Swarm satellite data, and also relied on geomagnetic indices derived from the ground observatory network. The ground observatories played a crucial role as independent data in validating our candidates. This paper also provides a retrospective assessment of the CU/NCEI candidate model to the previous IGRF (IGRF-12) and discusses the impact of differences between candidate and final IGRF models on global model errors.

Abstract In December 2019, the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group (V-MOD) adopted the thirteenth generation of the International Geomagnetic Reference Field (IGRF). This IGRF updates the previous generation with a definitive main field model for epoch 2015.0, a main field model for epoch 2020.0, and a predictive linear secular variation for 2020.0 to 2025.0. This letter provides the equations defining the IGRF, the spherical harmonic coefficients for this thirteenth generation model, maps of magnetic declination, inclination and total field intensity for the epoch 2020.0, and maps of their predicted rate of change for the 2020.0 to 2025.0 time period.

Abstract In this study, we have derived field-aligned currents (FACs) from magnetometers onboard the Defense Meteorological Satellite Project (DMSP) satellites. The magnetic latitude versus local time distribution of FACs from DMSP shows comparable dependences with previous findings on the intensity and orientation of interplanetary magnetic field (IMF) B y and B z components, which confirms the reliability of DMSP FAC data set. With simultaneous measurements of precipitating particles from DMSP, we further investigate the relation between large-scale FACs and precipitating particles. Our result shows that precipitation electron and ion fluxes both increase in magnitude and extend to lower latitude for enhanced southward IMF B z , which is similar to the behavior of FACs. Under weak northward and southward B z conditions, the locations of the R2 current maxima, at both dusk and dawn sides and in both hemispheres, are found to be close to the maxima of the particle energy fluxes; while for the same IMF conditions, R1 currents are displaced further to the respective particle flux peaks. Largest displacement (about 3.5°) is found between the downward R1 current and ion flux peak at the dawn side. Our results suggest that there exists systematic differences in locations of electron/ion precipitation and large-scale upward/downward FACs. As outlined by the statistical mean of these two parameters, the FAC peaks enclose the particle energy flux peaks in an auroral band at both dusk and dawn sides. Our comparisons also found that particle precipitation at dawn and dusk and in both hemispheres maximizes near the mean R2 current peaks. The particle precipitation flux maxima closer to the R1 current peaks are lower in magnitude. This is opposite to the known feature that R1 currents are on average stronger than R2 currents.

Abstract The technique of spherical elementary current systems (SECS) is a powerful way to determine ionospheric and field-aligned currents (FAC) from magnetic field measurements made by low-Earth-orbiting satellites, possibly in combination with magnetometer arrays on the ground. The SECS method consists of two sets of basis functions for the ionospheric currents: divergence-free (DF) and curl-free (CF) components, which produce poloidal and toroidal magnetic fields, respectively. The original CF SECS are only applicable at high latitudes, as they build on the assumption that the FAC flow radially into or out of the ionosphere. The FAC at low and middle latitudes are far from radial, which renders the method inapplicable at these latitudes. In this study, we modify the original CF SECS by including FAC that flow along dipolar field lines. This allows the method to be applied at all latitudes. We name this method dipolar elementary current systems (DECS). Application of the DECS to synthetic data, as well as Swarm satellite measurements are carried out, demonstrating the good performance of this method, and its applicability to studies of ionospheric current systems at low and middle latitudes.

Abstract For the past 20 years, state of the art geomagnetic core field models have relied heavily on magnetic measurements made from space-based instrumentation. These models have revealed rapid global magnetic field variations on sub-decadal timescales originating in Earth’s core. With the end of the CHAMP mission in 2010 and the launch of Swarm in late 2013, there has been a 3-year gap in high-quality satellite measurements of the geomagnetic field. Geomagnetic field models have therefore relied on ground observatory data to fill in this gap period. However, ground observatories are unable to provide a truly global picture of the core field and its temporal changes. Many satellites in operation carry vector fluxgate “platform” magnetometers for attitude control, which can offer an alternative to relying on ground observatory measurements during the gap period. However, these instruments need to be carefully calibrated in order to provide meaningful information on Earth’s core field. Some previous studies attempted to calibrate such instruments with a priori geomagnetic field models. This approach has several disadvantages: (1) errors in the model will introduce errors in the calibration parameters, and (2) relying on an a priori model may not be feasible in the post-Swarm era. In this paper, we develop a novel approach to build a time-dependent geomagnetic field model from platform magnetometer data, by co-estimating their calibration parameters with the internal field parameters. This method does not require an a priori geomagnetic field model, but does require a dataset of previously calibrated data. We use CHAMP, Swarm, and ground observatory measurements to supply this dataset, and incorporate platform magnetic measurements from DMSP and Cryosat-2 during the gap years. We find that the calibration parameters of DMSP and Cryosat-2 can be reliably estimated, and these missions provide meaningful information on rapid core field variations during the gap period.

Background Ultra‐high‐density mapping enables detailed mechanistic analysis of atrial reentrant tachycardia but has yet to be used to assess circuit conduction velocity (CV) patterns in adults with congenital heart disease. Methods and Results Circuit pathways and central isthmus CVs were calculated from consecutive ultra‐high‐density isochronal maps at 2 tertiary centers over a 3‐year period. Circuits using anatomic versus surgical obstacles were considered separately and pathway length 85% predicted isthmus block in all cases. Over >1 year of follow‐up, arrhythmia‐free survival was better for homogeneous CV patterns (90% versus 57%; P=0.04). Conclusions Ultra‐high‐density mapping‐guided CV analysis distinguishes atrial reentrant patterns in adults with congenital heart disease with surgical obstacles producing slower and smaller circuits. Very slow central isthmus CV may be essential for atrial tachycardia maintenance in small circuits, and non‐isthmus conduction time in tachycardia appears to be useful for rapid assessment of postablation conduction block.

BackgroundMyocardial slow conduction is a cornerstone of ventricular tachycardia (VT). Prolonged electrogram (EGM) duration is a useful surrogate parameter and manual annotation of EGM characteristics are widely used during catheter-based ablation of the arrhythmogenic substrate. However, this remains time-consuming and prone to inter-operator variability. We aimed to develop an algorithm for 3-D visualization of EGM duration relative to the 17-segment American Heart Association model.MethodsTo calculate and visualize EGM duration, in sinus rhythm acquired high-density maps of patients with ischemic cardiomyopathy undergoing substrate-based VT ablation using a 64-mini polar basket-catheter with low noise of 0.01 mV were analyzed. Using a custom developed algorithm based on standard deviation and threshold, the relationship between EGM duration, endocardial voltage and ablation areas was studied by creating 17-segment 3-D models and 2-D polar plots.Results140,508 EGMs from 272 segments (n = 16 patients, 94% male, age: 66±2.4, ejection fraction: 31±2%) were studied and 3-D visualization of EGM duration was performed. Analysis of signal processing parameters revealed that a 40 ms sliding SD-window, 15% SD-threshold and >70 ms EGM duration cutoff was chosen based on diagnostic odds ratio of 12.77 to visualize rapidly prolonged EGM durations. EGMs > 70 ms matched to 99% of areas within dense scar (ConclusionThe novel algorithm allows rapid visualization of prolonged EGM durations. This may facilitate more objective characterization of arrhythmogenic substrate in patients with ischemic cardiomyopathy.

Catheter ablation is a common therapy for atrial fibrillation but disrupts cardiac cholinergic neurons. Here the authors report that cholinergic neurons innervate heart ventricles and show that their ablation leads to increased susceptibility to ventricular arrhythmias in mouse models and in patients.

Purpose: The production of formulaic expressions (conversational speech formulas, pause fillers, idioms, and other fixed expressions) is excessive in the left hemisphere and deficient in the right hemisphere and in subcortical stroke. Speakers with Alzheimer's disease (AD), having functional basal ganglia, reveal abnormally high proportions of formulaic language. Persons with Parkinson's disease (PD), having dysfunctional basal ganglia, were predicted to show impoverished formulaic expressions in contrast to speakers with AD. This study compared participants with PD, participants with AD, and healthy control (HC) participants on protocols probing production and comprehension of formulaic expressions. Method: Spontaneous speech samples were recorded from 16 individuals with PD, 12 individuals with AD, and 18 HC speakers. Structured tests were then administered as probes of comprehension. Results: The PD group had lower proportions of formulaic expressions compared with the AD and HC groups. Comprehension testing yielded opposite contrasts: participants with PD showed significantly higher performance compared with participants with AD and did not differ from HC participants. Conclusions: The finding that PD produced lower proportions of formulaic expressions compared with AD and HC supports formulaic expressions. Contrasting results on formal testing of comprehension, whereby participants with AD performed significantly worse than participants with PD and HC participants, indicate differential effects on procedural and declarative knowledge associated with these neurological conditions.

The development of miniaturized nephroscopes which allow one-stage stone clearance with minimal morbidity has brought the role of shock wave lithotripsy (SWL) in stone management into question. Design innovations in SWL machines over the last decade have attempted to address this problem. We reviewed the recent literature on SWL using a MEDLINE/PUBMED research. For commenting on the future of SWL, we took the subjective opinion of two senior urologists, one mid-level expert, and an upcoming junior fellow. There have been a number of recent changes in lithotripter design and techniques. This includes the use of multiple focus machines and improved coupling designs. Additional changes involve better localization real-time monitoring. The main goal of stone treatment today seems to be to get rid of the stone in one session rather than being treated multiple times non-invasively. Stone treatment in the future will be individualized by genetic screening of stone formers, using improved SWL devices for small stones only. However, there is still no consensus about the design of the ideal lithotripter. Innovative concepts such as emergency SWL for ureteric stones may be implemented in clinical routine.