Brugada-type Electrocardiographic Pattern Induced by Fever

ST-segment elevation in Brugada syndrome is caused by a shift in the ionic current balance and the creation of a voltage gradient between the epicardium and the endocardium. This ionic mechanism have been shown to be temperature dependent. We describe a 33-year-old man who presented with fever with the dynamic electrocardiographic changes similar to the Brugada syndrome. These electrocardiographic anomalies disappeared when the temperature returned to normal

Effects of ULF wave power on relativistic radiation belt electrons: 8-9 October 2012 geomagnetic storm

Electromagnetic ultralow-frequency (ULF) waves are known to play a substantial role in radial transport, acceleration, and loss of relativistic particles trapped in the Earth's outer radiation belt. Using in situ observations by multiple spacecraft operating in the vicinity of outer radiation belts, we analyze the temporal and spatial behavior of ULF waves throughout the geomagnetic storm of 8–9 October 2012 and compare with the dynamics of relativistic electron fluxes on board the twin Van Allen Probes spacecraft. The analysis shows that the relativistic electron fluxes reduce from their prestorm levels during the first phase of the storm and rapidly increase during the second phase of the storm. We demonstrate that the behavior of ULF wave power changes throughout the storm, from ULF oscillations being a mixture of compressional and shear magnetic components during the first phase of the storm to ULF oscillations being dominated by transverse (shear) components during the second phase. We analyze the parameters of ULF-driven radial diffusion throughout the storm and compare the observed diffusion coefficients with their statistical averages. We demonstrate that the observed diffusion coefficients are strong enough to impact the redistribution of relativistic electron fluxes from and to the outer boundary of radiation belts and the diffusion might influence the effects of any local electron acceleration by transporting fluxes inward or outward according to phase space density gradients

Postępowanie w przypadku zatoru powietrznego tętnic wieńcowych podczas implantacji stentów wewnątrzwieńcowych

Coronary air embolism is a rare complication of cardiac catheterisation. We describe an alternative method of managing this complication which may be preferable to conventional methods. Kardiol Pol 2010; 68, 6: 716-71

Determining the mode, frequency, and azimuthal wave number of ULF waves during a HSS and moderate geomagnetic storm

Ultra-low frequency (ULF) waves play a fundamental role in the dynamics of the inner-magnetosphere and outer radiation belt during geomagnetic storms. Broadband ULF wave power can transport energetic electrons via radial diffusion and discrete ULF wave power can energize electrons through a resonant interaction. Using observations from the Magnetospheric Multiscale (MMS) mission, we characterize the evolution of ULF waves during a high-speed solar wind stream (HSS) and moderate geomagnetic storm while there is an enhancement of the outer radiation belt. The Automated Flare Inference of Oscillations (AFINO) code is used to distinguish discrete ULF wave power from broadband wave power during the HSS. During periods of discrete wave power and utilizing the close separation of the MMS spacecraft, we estimate the toroidal mode ULF azimuthal wave number throughout the geomagnetic storm. We concentrate on the toroidal mode as the HSSs compresses the day side magnetosphere resulting in an asymmetric magnetic field topology where toroidal mode waves can interact with energetic electrons. Analysis of the mode structure and wave numbers demonstrates that the generation of the observed ULF waves is a combination of externally driven waves, via the Kelvin-Helmholtz instability, and internally driven waves, via unstable ion distributions. Further analysis of the periods and toroidal azimuthal wave numbers suggests that these waves can couple with the core electron radiation belt population via the drift resonance during the storm. The azimuthal wave number and structure of ULF wave power (broadband or discrete) have important implications for the inner-magnetospheric and radiation belt dynamics

On the Relative Strength of Electric and Magnetic ULF Wave Radial Diffusion During the March 2015 Geomagnetic Storm

In this paper, we study electron radial diffusion coefficients derived from Pc4‐Pc5 ultralow frequency (ULF) wave power during the intense geomagnetic storm on 17–18 March 2015. During this storm the population of highly relativistic electrons was depleted within 2 hr of the storm commencement. This radial diffusion, depending upon the availability of source populations, can cause outward radial diffusion of particles and their loss to the magnetosheath, or inward transport and acceleration. Analysis of electromagnetic field measurements from Geostationary Operational Environment Satellite (GOES), Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite, and ground‐based magnetometers shows that the main phase storm‐specific radial diffusion coefficients do not correspond to statistical estimates. Specifically, during the main phase, the electric diffusion ( urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0001) is reduced, and the magnetic diffusion ( urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0002) is increased, compared to empirical models based on Kp. Contrary to prior results, the main phase magnetic radial diffusion cannot be neglected. The largest discrepancies, and periods of dominance of urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0003 over urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0004, occur during intervals of strongly southward IMF. However, during storm recovery, both magnetic and electric diffusion rates are consistent with empirical estimates. We further verify observationally, for the first time, an energy coherence for both urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0005 and urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0006 where diffusion coefficients do not depend on energy. We show that, at least for this storm, properly characterizing main phase radial diffusion, potentially associated with enhanced ULF wave magnetopause shadowing losses, cannot be done with standard empirical models. Modifications, associated especially with southward IMF, which enhance the effects of urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0007 and introduce larger main phase outward transport losses, are needed

Energy deposition in the ionosphere through a global field line resonance

International audienceWe present an interval whereby we can estimate the energy dissipation in the ionosphere through an externally-driven field line resonance. In this paper, we utilise an interval described in general by Rae et al. (2005), where the global magnetospheric cavity was shown to be energised via a high solar wind speed stream. Using the ground-based instrumentation available, we estimate the spatial extent of the generated pulsations to be at least 10° in latitude and 65° in longitude, a sizeable fraction of the dusk-sector ionosphere. Using a fortuitous conjunction with the Polar spacecraft, we compare point measurements of the net downward Poynting vector to the estimated Joule heating rate in the ionosphere, and find that model values of the Pedersen conductance are reasonable. In the interval of interest, we estimate the total dissipation rate during a global field line resonance to be comparable to that reported in substorm studies. Previous studies have estimated the total energy deposition via field line resonance to be up to 4% of that deposited during a small substorm. However, in this paper we find that the total energy deposited via Joule heating may actually be 30% or more of the energy deposited in the ionosphere during a substorm cycle using a conservative estimate of the pulsation duration

Diagnosing the Role of Alfvén Waves in Magnetosphere-Ionosphere Coupling: Swarm Observations of Large Amplitude Nonstationary Magnetic Perturbations During an Interval of Northward IMF

High-resolution multispacecraft Swarm data are used to examine magnetosphere-ionosphere coupling during a period of northward interplanetary magnetic field (IMF) on 31 May 2014. The observations reveal a prevalence of unexpectedly large amplitude (>100 nT) and time-varying magnetic perturbations during the polar passes, with especially large amplitude magnetic perturbations being associated with large-scale downward field-aligned currents. Differences between the magnetic field measurements sampled at 50 Hz from Swarm A and C, approximately 10 s apart along track, and the correspondence between the observed electric and magnetic fields at 16 samples per second, provide significant evidence for an important role for Alfvén waves in magnetosphere-ionosphere coupling even during northward IMF conditions. Spectral comparison between the wave E- and B-fields reveals a frequency-dependent phase difference and amplitude ratio consistent with interference between incident and reflected Alfvén waves. At low frequencies, the E/B ratio is in phase with an amplitude determined by the Pedersen conductance. At higher frequencies, the amplitude and phase change as a function of frequency in good agreement with an ionospheric Alfvén resonator model including Pedersen conductance effects. Indeed, within this Alfvén wave incidence, reflection, and interference paradigm, even quasi-static field-aligned currents might be reasonably interpreted as very low frequency (ω → 0) Alfvén waves. Overall, our results not only indicate the importance of Alfvén waves for magnetosphere-ionosphere coupling but also demonstrate a method for using Swarm data for the innovative experimental diagnosis of Pedersen conductance from low-Earth orbit satellite measurements

ULF wave activity in the magnetosphere: resolving solar wind interdependencies to identify driving mechanisms

Ultra-low frequency (ULF) waves in the magnetosphere are involved in the energisation and transport of radiation belt particles and are strongly driven by the external solar wind. However, the interdependency of solar wind parameters and the variety of solar wind-magnetosphere coupling processes make it difficult to distinguish the effect of individual processes and to predict magnetospheric wave power using solar wind properties. We examine fifteen years of dayside ground-based measurements at a single representative frequency (2.5 mHz) and a single magnetic latitude (corresponding to $L \sim 6.6 R_E$). We determine the relative contribution to ULF wave power from instantaneous non-derived solar wind parameters, accounting for their interdependencies. The most influential parameters for ground-based ULF wave power are solar wind speed $v_{sw}$, southward interplanetary magnetic field component $B_z < 0$ and summed power in number density perturbations $\delta N_p$. Together, the subordinate parameters $B_z$ and $\delta N_p$ still account for significant amounts of power. We suggest that these three parameters correspond to driving by the Kelvin-Helmholtz instability, formation and/or propagation of flux transfer events and density perturbations from solar wind structures sweeping past the Earth. We anticipate that this new parameter reduction will aid comparisons of ULF generation mechanisms between magnetospheric sectors and will enable more sophisticated empirical models predicting magnetospheric ULF power using external solar wind driving parameters

Energetic Electron and Proton Interactions with Pc5 Ultra Low Frequency (ULF) Waves during the Great Geomagnetic Storm of 15–16 July 2000

The dynamics of the outer zone radiation belt has received a lot of attention mainly due to the correlation between the occurrence of enhancing relativistic electron flux and spacecraft operation anomalies or even failures (e.g., Baker et al. 1994). Relativistic electron events are often observed during great storms associated with ultra low frequency (ULF) waves. For example, a large buildup of relativistic electrons was observed during the great storm of March 24, 1991 (e.g., Li et al. 1993; Hudson et al. 1995; Mann et al. 2013). However, the dominant processes which accelerate magnetospheric radiation belt electrons to MeV energies are not well understood. In this paper, we present observations of Pc5 ULF waves in the recovery phase of the Bastille day storm of July 16, 2000 and electron and proton flux simultaneously oscillating with the same frequencies as the waves. The mechanism for the observed electron and proton flux modulations is examined using groundbased and satellite observations. During this storm time, multiple packets of discrete frequency Pc5 ULF waves appeared associated with energetic particle flux oscillations. We model the drift paths of electrons and protons to determine if the particles drift through the ULF wave to understand why some particle fluxes are modulated by the ULF waves and others are not. We also analyze the flux oscillations of electrons and protons as a function of energy to determine if the particle modulations are caused by a ULF wave drift resonance or advection of a particle density gradient. We suggest that the energetic electron and proton modulations by Pc5 ULF waves provide further evidence in support of the important role that ULF waves play in outer radiation belt dyanamics during storm times

The global statistical response of the outer radiation belt during geomagnetic storms

Using the total radiation belt electron content calculated from Van Allen Probe phase space density (PSD), the time-dependent and global response of the outer radiation belt during storms is statistically studied. Using PSD reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and non-adiabatic effects, and revealing a clear modality and repeatable sequence of events in storm-time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant (mu) dependent behaviour in the seed (150 MeV/G), relativistic (1000 MeV/G), and ultra-relativistic (4000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, whilst the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly mu-dependent and occurs at low mu first, appearing to be repeatable from storm to storm