Effect of neurostimulation on cognition and mood in refractory epilepsy.

Epilepsy is a common, debilitating neurological disorder characterized by recurrent seizures. Mood disorders and cognitive deficits are common comorbidities in epilepsy that, like seizures, profoundly influence quality of life and can be difficult to treat. For patients with refractory epilepsy who are not candidates for resection, neurostimulation, the electrical modulation of epileptogenic brain tissue, is an emerging treatment alternative. Several forms of neurostimulation are currently available, and therapy selection hinges on relative efficacy for seizure control and amelioration of neuropsychiatric comorbidities. Here, we review the current evidence for how invasive and noninvasive neurostimulation therapies affect mood and cognition in persons with epilepsy. Invasive therapies include vagus nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS). Noninvasive therapies include trigeminal nerve stimulation (TNS), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS). Overall, current evidence supports stable cognition and mood with all neurostimulation therapies, although there is some evidence that cognition and mood may improve with invasive forms of neurostimulation. More research is required to optimize the effects of neurostimulation for improvements in cognition and mood

Prediction of hydrocarbon reservoirs within coal-bearing formations

This paper presents a case study on the prediction of hydrocarbon reservoirs within coal-bearing formations of the Upper Palaeozoic. The target reservoirs are low-permeability low-pressure tight-sandstone reservoirs in the Daniudi Gas Field, Ordos Basin, China. The prime difficulty in reservoir prediction is caused by the interbedding coal seams within the formations, which generate low-frequency strong-amplitude reflections in seismic profiles. To tackle this difficulty, first, we undertook a careful analysis regarding the stratigraphy and lithology of these coal-bearing formations within the study area. Then, we conducted a geostatistical inversion using 3D seismic data and obtained reservoir parameters including seismic impedance, gamma ray, porosity and density. Finally, we carried out a reservoir prediction in the coal-bearing formations, based on the reservoir parameters obtained from geostatistical inversion and combined with petrophysical analysis results. The prediction result is accurately matched with the actual gas-test data for the targeted four segments of the coal-bearing formations

3D seismic inversion by model parameterization with Fourier coefficients

In seismic inversion, the subsurface model can be parameterized by a truncated Fourier series, and the inversion problem is then the inversion of the Fourier coefficients. To improve the efficiency of the evaluation of the Fourier coefficients and the reconstruction of the model from the inverted coefficients, we propose to use the efficient implementation of the fast Fourier transform (FFT) to speed up these two calculations. By using the FFT pair, the computation time for 3D subsurface models with realistic size could be reduced by two to three orders of magnitude compared to conventional methods. When this model parameterization scheme is applied to seismic impedance inversion, we proposed two strategies to further improve the efficiency. One is to invert the Fourier coefficients from small-valued numbers to large-valued numbers, and the other is to divide the seismic data into subgroups and use part of them for the inversion of the Fourier coefficients. Both strategies are helpful for efficient inversion of the Fourier coefficients from the seismic data. Moreover, thanks to this model parameterization scheme, the Fourier coefficients are inverted in a multi-trace manner, and the impedance model reconstructed from the inverted Fourier coefficients has good spatial continuity. The scheme is able to generate stable and continuous impedance models from the inversion of seismic data with missing traces, with affordable computation times

Seismic resolution enhancement in shale-oil reservoirs

We developed a case study of seismic resolution enhancement for shale-oil reservoirs in the Q Depression, China, featured by rhythmic bedding. We proposed an innovative methodology for the resolution enhancement, a full-band extension method, and implemented this method in three consecutive steps: wavelet extraction, filter construction and data filtering. First, we extracted a constant-phase wavelet from the entire seismic data set. Then, we constructed the full-band extension filter in the frequency domain using the least-squares inversion method. Finally, we applied the band extension filter to the entire seismic data set. We demonstrated that this full-band extension method, with a stretched frequency band from 7-70 Hz to 2-90 Hz, may significantly enhance the 3D seismic resolution and distinguish reflection events of the rhythmite groups in shale-oil reservoirs

Teacher Education

The young today are facing a world in which communication and information revolution has led to changes in all spheres: scientific, technological, political, economic, social and cultural. To be able to prepare our young people face the future with confidence purpose and responsibility, the crucial role of teachers cannot be overemphasized. Given these multidimensional demands, Role of teachers also have to change. In the past, teachers used to be a major source of knowledge, the leader and educator of their students school life. The changes that took place in education have initiated to change the role of teachers. In this article we will examine how the role of teachers in the present society has to change

Reconsideration of Second Harmonic Generation from neat Air/Water Interface: Broken of Kleinman Symmetry from Dipolar Contribution

It has been generally accepted that there are significant quadrupolar and bulk contributions to the second harmonic generation (SHG) reflected from the neat air/water interface, as well as common liquid interfaces. Because there has been no general methodology to determine the quadrupolar and bulk contributions to the SHG signal from a liquid interface, this conclusion was reached based on the following two experimental phenomena. Namely, the broken of the macroscopic Kleinman symmetry, and the significant temperature dependence of the SHG signal from the neat air/water interface. However, because sum frequency generation vibrational spectroscopy (SFG-VS) measurement of the neat air/water interface observed no apparent temperature dependence, the temperature dependence in the SHG measurement has been reexamined and proven to be an experimental artifact. Here we present a complete microscopic analysis of the susceptibility tensors of the air/water interface, and show that dipolar contribution alone can be used to address the issue of broken of the macroscopic Kleinman symmetry at the neat air/water interface. Using this analysis, the orientation of the water molecules at the interface can be obtained, and it is consistent with the measurement from SFG-VS. Therefore, the key rationales to conclude significantly quadrupolar and bulk contributions to the SHG signal of the neat air/water interface can no longer be considered as valid as before. This new understanding of the air/water interface can shed light on our understanding of the nonlinear optical responses from other molecular interfaces as well