Explore the vast range of titles available.

We present the first observations at an interplanetary shock of large-amplitude (> 100 mV/m pk-pk) solitary waves and large-amplitude (approx.30 mV/m pk-pk) waves exhibiting characteristics consistent with electron Bernstein waves. The Bernstein-like waves show enhanced power at integer and half-integer harmonics of the cyclotron frequency with a broadened power spectrum at higher frequencies, consistent with the electron cyclotron drift instability. The Bernstein-like waves are obliquely polarized with respect to the magnetic field but parallel to the shock normal direction. Strong particle heating is observed in both the electrons and ions. The observed heating and waveforms are likely due to instabilities driven by the free energy provided by reflected ions at this supercritical interplanetary shock. These results offer new insights into collisionless shock dissipation and wave-particle interactions in the solar wind.

The properties of magnetic reconnection in an asymmetric magnetopause current layer are investigated using three‐dimensional particle‐in‐cell simulations and THEMIS subsolar magnetopause crossings. The strong density gradient region on the magnetosphere side of the current layer is found to be unstable to a k⋅B = 0 lower hybrid drift instability type mode with dominant wave number kyρe ∼ 0.5. The accompanying perpendicular electric fields are intense (Ey ∼ 4vAB0 ∼ 100 mV/m) with characteristic frequencies (typically two narrowband signals) between the proton cyclotron and lower hybrid frequencies. In the observations, neither the wave amplitude nor frequency appears to be sensitive to the value of any guide magnetic field or to the degree of asymmetry in Bz/n across the magnetopause. These electric fields remain confined away from the reconnection X line and do not appear to affect the value of the reconnection rate. Key Points The subsolar magnetopause is unstable to a localized LHDI type mode The electric fields are intense (100mV/m) and contain discrete frequencies The electric fields remain confined away from the X line

This paper analyses the promotion of culture-based tourism as a tool for cultural conservation and community livelihoods improvement in Buganda region, Uganda. A pragmatic approach was adopted to explore the existing cultural heritage resources in Buganda and their conservation for tourism as a means for community development. Data were collected using documentary reviews, focus group discussions with key actors in the tourism subsector, and a questionnaire interview. Results indicate that culture-based tourism is positively correlated to cultural conservation and community livelihood. The paper highlights the importance of culture-based tourism and culture conservation on community livelihood in the context of Uganda. The significant results obtained in this case study also show that cultural conservation was a strong predictor of community livelihoods. It is concluded that if culture-based tourism is enhanced and promoted, it has the potential to influence people’s livelihoods through the income generated from tourism activities and employment. This in turn contributes to the preservation of cultural heritage sites and hence sustainability. There is however need to investigate the novel and innovative ways of marketing and promoting cultural tourism in Uganda to enable improvement in people’s livelihood. It is also necessary to devise ways on how to increase community involvement in planning, implementation, and securing benefits of culture-based tourism.

We present a detailed case study of the plasma and fields measured by the Cluster spacecraft fleet at the high‐altitude auroral zone (∼3.5 RE) across the plasma sheet boundary layer and into the polar cap. This event, which occurred during quiet geomagnetic conditions (Kp = 1+, AE = 50 nT), is of particular interest in that Cluster provides measurements at key instances during the time development of a new large‐scale auroral arc system. Central to the formation of the arc system is the depletion of ionospheric plasma through a region of small‐scale, field‐aligned currents having the properties of Alfvén waves. This depletion occurred prior to the growth of and ultimately bounded a well‐defined equatorward moving, upward and downward current sheet pair. In association with the transverse scales approaching the electron inertial scale, the Alfvénic currents have amplitudes that appear to be attenuated subsequent to the formation of the cavity. Potential structures essentially time invariant over particle transit times (quasi‐static) associated with the current pair are identified and observed to drive a poleward boundary intensification (PBI) identified in coincident IMAGE satellite far ultraviolet measurements. The PBI formed in association with a local thickening of the plasma sheet via the injection of new magnetospheric plasma, which may be the result of a bursty, patchy reconnection process. Estimates of the ionospheric equatorward velocity and thickness of the PBI are consistent with their ionospheric mapped cavity counterparts, suggesting that the motion and thickness are controlled by the plasma and electrodynamic features at or above the altitude sampled by Cluster. The magnitude of the upward and downward current region parallel potentials is correlated with the temperature of the newly injected electrons suggesting that the electron temperature is an important controlling factor. These novel observations indicate that quasi‐static systems of field‐aligned currents do form out of the highly dynamic Alfvénic region at the plasma sheet boundary layer, and perhaps suggest that the Alfvénic region can be the initial stage in the development of quasi‐static systems. The observed time sequence of the currents is qualitatively similar to the expectations of transient response models of magnetospheric‐ionospheric coupling, however, such models may need to be modified to account for the attenuation of electron inertial scale currents/Alfvén waves.

We report occasional observations of two simultaneously distinct ion foreshock components recorded by the Cluster spacecraft upstream of the Earth's bow shock. In most occurrences, the lower-energy population originates as a field-aligned beam (FAB) associated with quasi-perpendicular regions, which loses energy as the IMF rotates into oblique geometries. A second beam, with energies in excess of ~10 keV, appears sometimes in association with the onset of ultra-low frequency (ULF) waves, and sometimes ahead of the appearance of the latter. Measurements from the mass spectrometer indicate that both beams consist of protons. While the lower-speed beam is well-accounted for by a known reflection mechanism, the non-radial IMF orientations as well as other arguments seem to rule out magnetosheath or magnetospheric sources for the higher energy component. The wave characteristics are typical of the oblique foreshock and we have found that they are in cyclotron-resonance with the low speed beam (FAB). These observations constitute a theoretical challenge since conventional mechanisms described in the literature cannot account for the production of beams at two different energies.

Pulmonary vein antrum isolation (PVI) as a treatment of paroxysmal atrial fibrillation (AF) is associated with a high rate of success; however, outcomes for treating persistent and long-standing persistent AF with PVI alone are substantially lower and often require multiple procedures to maintain long-term freedom from atrial arrhythmias. Foci and/or substrate outside the pulmonary veins, particularly in the left atrial appendage (LAA), has been identified as a key mechanism in the maintenance of persistent AF and long-standing persistent AF. The goals of the study are to evaluate the safety and effectiveness of the LARIAT System to percutaneously isolate and ligate the LAA and to determine if LAA ligation as adjunctive therapy to PVI improves maintenance of sinus rhythm in patients with persistent and long-standing persistent AF. The trial is a prospective, multicenter, randomized controlled study. The trial design incorporates a Bayesian adaptive design that will randomize a maximum of 600 patients with persistent or long-standing persistent AF to LAA ligation and PVI vs PVI alone in a 2:1 randomization. The primary end points include 30-day safety of the LARIAT procedure and freedom from documented AF, atrial flutter, or atrial tachycardia of more than 30 seconds at 12 months after the PVI off antiarrhythmic drugs. Key secondary outcomes include a composite of cardiovascular death and stroke, as well as quality of life. The aMAZE trial will determine if LAA ligation as adjunctive therapy to PVI increases the efficacy of maintaining sinus rhythm in patients with persistent and long-standing persistent AF.

Observations of a unique cusp feature at low and mid altitudes are reported. This feature has a consistent double-peaked or \"V\"-shaped structure at the equatorward edge of high-latitude particle precipitation flux, and is predominantly present for high IMF B^sub y^ conditions. The observations are consistent with the Crooker ('A split separator line merging model of the dayside magnetopause', J. Geophys. Res. 90 (1985) 12104, 'Mapping the merging potential from the magnetopause to the ionosphere through the dayside cusp', J. Geophys. Res. (1988) 93 7338.) antiparallel merging model, which predicts a narrow wedge-shaped cusp whose geometry depends greatly on the dawn/dusk component of the IMF. Various observations are presented at low altitudes (DE-2, Astrid-2, Munin, UARS, DMSP) and at mid altitudes (DE-1, Cluster) that suggest a highly coherent cusp feature that is consistent with the narrow, wedge-shaped cusp of Crooker (1988), and contains persistent wave signatures that are compatible with previously reported high-altitude measurements. A statistical survey of Astrid-2 and DMSP satellite data is also presented, which shows this feature to be persistent and dependent on the IMF angle at the magnetopause, as expected. Thus, the cusp signatures observed at a wide range of altitudes present a coherent picture that may be interpreted in terms of a footprint of the magnetopause current layer.[PUBLICATION ABSTRACT]

Patients with diabetes mellitus, prior myocardial infarction, older age, and a relatively preserved left ventricular ejection fraction remain at risk for sudden cardiac death that is potentially amenable by the subcutaneous implantable cardioverter defibrillator with a good risk-benefit profile. The launched MADIT S-ICD study is designed to test the hypothesis that post–myocardial infarction diabetes patients with relatively preserved ejection fraction of 36%-50% will have a survival benefit from a subcutaneous implantable cardioverter defibrillator.

Prior reports describing magnetic resonance (MR) imaging abnormalities in arrhythmogenic right ventricular dysplasia (ARVD/C) were limited by nonuniform inclusion criteria. The aim of our study was to define the prevalence, sensitivity, and specificity of quantitative MR imaging findings in the probands of multidisciplinary study of right ventricular dysplasia. Individuals with ventricular arrhythmias of left bundle-branch block morphology meeting the Task Force criteria for ARVD/C underwent MR imaging. The MR images were compared with 10 patients with idiopathic ventricular tachycardia (VT) and 25 controls. Of the 42 study probands, 40 met the Task Force criteria exclusive of MR imaging findings. All MR images were interpreted in a blinded fashion. Right ventricle fat infiltration was reported in 24 (60%) probands and none of the patients with idiopathic VT or controls. Six patients (15%) had fat infiltration of the left ventricle. Right ventricle regional dysfunction was observed in 32 probands (80%) and none of the patients with idiopathic VT or controls. Qualitative RV function was abnormal in 26 probands (60%); however, quantitative RV ejection fraction was abnormal in 85% (24/28) of the probands. An RV ejection fraction <50% had a sensitivity of 73% and a specificity of 95% in diagnosis of ARVD/C. Fat infiltration is seldom the only MR imaging abnormality and is less sensitive for ARVD/C diagnosis compared with RV regional dysfunction. Qualitative estimates of RV function may underestimate the prevalence of RV dysfunction in ARVD/C. Quantitative evaluation of RV by MR imaging may have a high sensitivity and specificity for ARVD/C diagnosis.

It is unknown whether recurrence of atrial fibrillation (AF) is related to severity of left ventricular diastolic dysfunction (LVDD) before ablation in patients with preserved left ventricular ejection fraction (LVEF). We tested the hypothesis that the presence and/or severity of LVDD before catheter ablation are related to AF recurrence during the 12-month follow-up period in patients with normal LVEF. We also aimed to determine what echocardiographic and Doppler indexes of LVDD before ablation are associated with recurrence of AF after ablation. We identified 198 patients with normal LVEF who underwent catheter ablation for AF with evidence of normal sinus rhythm within 1 year before ablation. The recurrence rate during 12-month follow-up period was assessed. Of the 198 patients, 76 patients (38%) had symptomatic recurrence and 122 patients (62%) had no recurrence. None of the independent variables, including mitral valve Doppler E and A peak velocities, E/A ratio, tissue Doppler e′ and a′ peak velocities, left atrial volume index, isovolumic relaxation time, and deceleration time, predicted recurrence. Patients with average E/e′ ratio >13, however, had increased recurrence (67% vs 35%, odds ratio 3.70, 95% confidence interval 1.21 to 11.3, p <0.05). In conclusion, there was no difference in the severity of LVDD using conventional echocardiographic indexes of LVDD in patients with or without recurrence of AF ablation. However, patients with average E/e′ ratio >13 did have an increased recurrence rate of AF at 12 months after procedure. Therefore, E/e′ ratio, indicative of increased left atrial pressure, may serve as a marker for AF recurrence after ablation.