[Waves Paz Analyzer Crack
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Methods: Forty consecutive F-waves were recorded from the ulnar and peroneal nerve in 52 patients with ALS and 52 healthy control subjects. Data were imported into the F Wave Analyzer which identifies Freps and groups them. Parameters of Freps and non repeater F-waves (Fnonreps) were compared.
Conclusion: In ALS, the high numbers of Freps, reduced overall F-wave persistence and increased F-wave amplitude measurements in a relatively unaffected nerve-muscle complex reflects excitability alterations of the corresponding motor neuron pool. Overall, automatic analysis facilitates accurate and fast detection of Freps and could be useful in other clinical settings.
The High Frequency Analyzer (HFA) is a subsystem of the Plasma Wave Experiment onboard the Arase (ERG) spacecraft. The main purposes of the HFA include (1) determining the electron number density around the spacecraft from observations of upper hybrid resonance (UHR) waves, (2) measuring the electromagnetic field component of whistler-mode chorus in a frequency range above 20 kHz, and (3) observing radio and plasma waves excited in the storm-time magnetosphere. Two components of AC electric fields detected by Wire Probe Antenna and one component of AC magnetic fields detected by Magnetic Search Coils are fed to the HFA. By applying analog and digital signal processing in the HFA, the spectrograms of two electric fields (EE mode) or one electric field and one magnetic field (EB mode) in a frequency range from 10 kHz to 10 MHz are obtained at an interval of 8 s. For the observation of plasmapause, the HFA can also be operated in PP (plasmapause) mode, in which spectrograms of one electric field component below 1 MHz are obtained at an interval of 1 s. In the initial HFA operations from January to July, 2017, the following results are obtained: (1) UHR waves, auroral kilometric radiation (AKR), whistler-mode chorus, electrostatic electron cyclotron harmonic waves, and nonthermal terrestrial continuum radiation were observed by the HFA in geomagnetically quiet and disturbed conditions. (2) In the test operations of the polarization observations on June 10, 2017, the fundamental R-X and L-O mode AKR and the second-harmonic R-X mode AKR from different sources in the northern polar region were observed. (3) The semiautomatic UHR frequency identification by the computer and a human operator was applied to the HFA spectrograms. In the identification by the computer, we used an algorithm for narrowing down the candidates of UHR frequency by checking intensity and bandwidth. Then, the identified UHR frequency by the computer was checked and corrected if needed by the human operator. Electron number density derived from the determined UHR frequency will be useful for the investigation of the storm-time evolution of the plasmasphere and topside ionosphere.
In addition to editing the mission data packets, onboard software for the HFA is required to perform onboard automatic determination of UHR frequency using the HFA spectrogram. The determined UHR frequency is provided to S-WPIA at an interval of 1 s for onboard determination of the expected velocity of the resonant electrons with observed chorus emissions.
Example of the spectrograms obtained in PP-1 and EB modes. The AC electric field is indicated in a. The AC magnetic field is indicated in b. The electron cyclotron frequency is indicated by white curve
After confirming that the gains of Eu and Ev are the same in the EE-UV mode operation performed in initial check phase, we started the operation in EE-LR mode, in which the left- and right-handed electric fields, \(\left\langle \left \right\rangle\) and \(\left\langle \tildeE_\textR \right \right\rangle\), are obtained. A typical example of the spectrogram obtained in test operations of EE-LR mode on June 10, 2017, is shown in Fig. 6. The total intensity of left- and right-handed components \(\left\langle \left \right\rangle + \left\langle \left \right\rangle\) and the axial ratio \(\left( \left\langle ^2 \right\rangle - \left\langle \tildeE_\textL \right \right\rangle \right) \mathord\left/ \vphantom \left( \left\langle \left \right\rangle - \left\langle \left \right\rangle \right) \left( \left\langle \left \right\rangle + \left\langle \left \right\rangle \right) \right. \kern-0pt \left( \left\langle \left \right\rangle + \left\langle \tildeE_\textL \right \right\rangle \right)\) of the radio and plasma waves are indicated in Fig. 6a, b, respectively. Since the polarization in the HFA observation is defined with respect to the anti-sunward direction, and the magnetic field is in the sunward direction in the northern hemisphere on the night side, the positive axial ratio (red) indicates left-hand polarization with respect to the magnetic field; a negative axial ratio (blue) indicates right-hand polarization with respect to the magnetic field. AKR in a frequency range from 100 to 500 kHz is found in the spectrograms. There are both polarized components below 300 kHz and right-handed component only above the 300 kHz. In addition, although some of left-handed components (red) below 300 kHz are masked by intense right-handed components (blue), left-handed components (red) below 300 kHz always accompany right-handed components (blue) with similar spectral structures above 300 kHz. In this observation, the spacecraft is around a geocentric distance of 5 RE and a geomagnetic latitude of +30, and AKR from the southern polar region cannot be observed due to shielding by the plasmasphere. Therefore, the AKR is considered to be from two different sources in the northern polar regions. One is the typical R-X mode AKR below 300 kHz, and the other is the fundamental L-O mode AKR below 300 kHz, with the second-harmonic component in R-X mode as reported by several previous studies (Benson 1982; Mellott et al. 1986). They are suggested to be generated depending on plasma density in AKR sources; when fpe/fce is less than 0.3, a high growth rate in R-X mode is expected. When fpe/fce is as large as 0.3, the growth rate in the fundamental L-O mode and second-harmonic R-X mode can be higher than that in the fundamental R-X mode (Wu and Qiu 1983; Melrose et al. 1984). The AKR from two sources at different locations is considered to be observed simultaneously probably due to the effects of mode filtering around the plasmasphere, as discussed by Hashimoto (1984). We also checked the survey plot of Cluster/WBD (Gurnett et al. 1997) provided via -pw.physics.uiowa.edu/cluster/ and confirmed that the spectra of intense (probably right-handed) AKR observed by Cluster in the southern hemisphere are quite different from the spectra of left-handed AKR observed by Arase in the northern hemisphere. This also suggests that the left-handed AKR observed by Arase in the northern hemisphere is not from the R-X mode AKR sources in the southern hemisphere. The start of EE-LR mode observation will bring us useful datasets for discussions on the plasma conditions, generation mechanisms at the AKR sources, and AKR propagation from the sources in the both northern and southern polar regions.
Datasets obtained in EE-LR mode will also be useful with regard to discussions on not only AKR but also kilometric continuum (KC). Since KC is observed as L-O mode waves in most cases, KC is considered to be generated by the linear mode conversion processes in plasma density gradients around the plasmapause. On the other hand, Kalaee and Katoh (2016) reported that R-X mode KC are also observed by the Akebono satellite, suggesting that R-X mode waves can be generated by nonlinear interactions between Z-mode waves and energetic electrons based on simulations. Further discussion will be enabled by HFA EE-LR mode data and energetic electron data around the plasmapause obtained by Arase/LEP-e (Kazama et al. 2017) and MEP-e (Kasahara et al. 2018a).
In this study, we chose an approach with semiautomatic identification of UHR frequency by the computer and a human operator. First, we applied an algorithm for identification of the UHR frequency to the HFA spectrogram data. The algorithm was developed not to identify UHR frequency in all cases but to identify it in easy cases. Then, a human operator checked the identifications made by the computer and corrected them if needed. A similar approach was also used by Kurth et al. (2015) to identify UHR frequency in spectrograms obtained by the Van Allen Probe. They also mentioned that inspections and corrections by a human operator were necessary. They used an algorithm called AURA (automated upper hybrid resonance detection algorithm), which identifies the UHR frequency at the peak of the spectrum weighted by a Gaussian function whose peak is at the previously identified UHR frequency. Although the algorithm is quite simple, and seems sufficiently effective, we used another step-by-step algorithm so that we could arrange multiple criteria and parameters manually to improve UHR identification.
Comparisons of identified UHR frequency. a UHR frequency automatically determined under geomagnetically quiet conditions. b UHR frequency automatically determined under geomagnetically disturbed conditions. c UHR frequency after the manual correction of that in b
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