High amplitude high frequency oscillations during posttraumatic epileptogenesis

Background: The aim of the present study was to investigate if high amplitude high frequency oscillations(haHFOs) could be a biomarker of posttraumatic epileptogenesis. Methods: After an initial craniotomy of rats and inducement of traumatic brain injury(TBI) through a fluid percussion, recording microelectrodes were implanted bilaterally in different brain areas.Wideband brain electrical activity was recorded intermittently from Day 1 of TBI and continued till week 21. HaHFO analysis was performed during the first 4 weeks to investigate whether the occurrence of this brain activity predicted development of epilepsy or not. Results: Of the 21 rats which received the TBI, 9 became epileptic(E+) and 12 did not(E-). HaH FOs were observed in the prefrontal and perilesional cortices, hippocampus, and striatum in both E+ and E-group. In comparison to the rats in E-, the E+ group showed a significant increase in the rate of haHFO from weeks 1 to 4 after TBI.Conclusion: The results indicate that an increase in the rate of haHFOs after TBI could be an electroencephalographic biomarker of posttraumatic epileptogenesis.

NUMERICAL EXPERIMENTS AND ANALYSIS OF DIGITAL FILTER INITIALIZATION FOR WRF MODEL

Initialization and initial imbalance problem were discussed in the context of a three-dimensional variational data assimilation system of the new generation"Weather Research and Forecasting Model". Several options of digital filter initialization have been tested with a rain storm case. It is shown that digital filter initialization, especially diabatic digital filter initialization and twice digital filter initialization, have effectively removed spurious high frequency noise from initial data for numerical weather prediction and produced balanced initial conditions. For six consecutive intermittent data assimilation cycles covering a 3-day period, mean initialization increments and impact on forecast variables are studied. DFI has been demonstrated to provide better adjustment of the hydrometeors and vertical velocity, reduced spin-up time, and improved forecast variables quantity.

0.15-μm T-gate In_(0.52)Al_(0.48)As/In_(0.53)Ga_(0.47)As InP-based HEMT with fmax of 390 GHz

In this paper, 0.15-μm gate-length In0.52Al0.48As/In0.53Ga0.47As InP-based high electron mobility transistors （HEMTs） each with a gate-width of 2×50 μm are designed and fabricated. Their excellent DC and RF characterizations are demonstrated. Their full channel currents and extrinsic maximum transconductance （gm,max） values are measured to be 681 mA/mm and 952 mS/mm, respectively. The off-state gate-to-drain breakdown voltage （BVGD） defined at a gate current of-1 mA/mm is 2.85 V. Additionally, a current-gain cut-off frequency （fT） of 164 GHz and a maximum oscillation frequency （fmax） of 390 GHz are successfully obtained; moreover, the fmax of our device is one of the highest values in the reported 0.15-μm gate-length lattice-matched InP-based HEMTs operating in a millimeter wave frequency range. The high gm,max, BVGD, fmax, and channel current collectively make this device a good candidate for high frequency power applications.