Beyond rates: time-varying dynamics of high frequency oscillations as a biomarker of the seizure onset zone

Objective. High frequency oscillations (HFOs) recorded by intracranial electrodes have generated excitement for their potential to help localize epileptic tissue for surgical resection. However, the number of HFOs per minute (i.e. the HFO 'rate') is not stable over the duration of intracranial recordings; for example, the rate of HFOs increases during periods of slow-wave sleep. Moreover, HFOs that are predictive of epileptic tissue may occur in oscillatory patterns due to phase coupling with lower frequencies. Therefore, we sought to further characterize between-seizure (i.e. 'interictal') HFO dynamics both within and outside the seizure onset zone (SOZ).Approach. Using long-term intracranial EEG (mean duration 10.3 h) from 16 patients, we automatically detected HFOs using a new algorithm. We then fit a hierarchical negative binomial model to the HFO counts. To account for differences in HFO dynamics and rates between sleep and wakefulness, we also fit a mixture model to the same data that included the ability to switch between two discrete brain states that were automatically determined during the fitting process. The ability to predict the SOZ by model parameters describing HFO dynamics (i.e. clumping coefficients and coefficients of variation) was assessed using receiver operating characteristic curves.Main results. Parameters that described HFO dynamics were predictive of SOZ. In fact, these parameters were found to be more consistently predictive than HFO rate. Using concurrent scalp EEG in two patients, we show that the model-found brain states corresponded to (1) non-REM sleep and (2) awake and rapid eye movement sleep. However the brain state most likely corresponding to slow-wave sleep in the second model improved SOZ prediction compared to the first model for only some patients.Significance. This work suggests that delineation of SOZ with interictal data can be improved by the inclusion of time-varying HFO dynamics

A Game Theoretic Analysis of a Regional Approach toward the Sustainability of Kolkata-Agartala Transit Route

This paper attempts to explore the possibilities of a viable transport network in the long run which can respond to the demand for communication by people of Tripura as well as the demand of Tripura’s projected economy. Since, Tripura is constantly facing the problem of lack of a smooth transportation and naturally, it is an economic imperative for this landlocked state to seek benefits for itself through greater regional integration. Most of the cargo originates from Kolkata (Port) and terminates at Guwahati and distributed to various destinations of north eastern states. This paper examines the perspectives of such cargo movement from Kolkata to Agartala and the strategic options of the transiting countries, namely Bangladesh and Myanmar. The development of a new transit route through Myanmar, depriving Bangladesh of its former monopoly, has modified the situation profoundly. The thrust of the paper is an analysis of the strategies that Bangladesh and Myanmar may pursue in transiting cargo for Agartala in terms of a game theoretic structure. The long run sustainability of such transit route from Kolkata to Agartala depends on regional cooperation among these countries in a political emotional state of nature

A Game Theoretic Analysis of a Regional Approach toward the Sustainability of Kolkata-Agartala Transit Route

This paper attempts to explore the possibilities of a viable transport network in the long run which can respond to the demand for communication by people of Tripura as well as the demand of Tripura’s projected economy. Since, Tripura is constantly facing the problem of lack of a smooth transportation and naturally, it is an economic imperative for this landlocked state to seek benefits for itself through greater regional integration. Most of the cargo originates from Kolkata (Port) and terminates at Guwahati and distributed to various destinations of north eastern states. This paper examines the perspectives of such cargo movement from Kolkata to Agartala and the strategic options of the transiting countries, namely Bangladesh and Myanmar. The development of a new transit route through Myanmar, depriving Bangladesh of its former monopoly, has modified the situation profoundly. The thrust of the paper is an analysis of the strategies that Bangladesh and Myanmar may pursue in transiting cargo for Agartala in terms of a game theoretic structure. The long run sustainability of such transit route from Kolkata to Agartala depends on regional cooperation among these countries in a political emotional state of nature

Optimal pricing policy of continental transit route: a study of Kolkata-Agartala transit route

The aim of this paper is to investigate the pricing policy of transhipment route for India to move cargo through Bangladesh from Kolkata port to the capital city of Tripura i.e. Agartala. Initially, Bangladesh was hesitating to allow India to provide transhipment facility for the north eastern region but India reciprocate it in right direction by providing similar facility to Bangladesh to reach the Himalayan landlocked countries like Nepal and Bhutan, thereby, actively participate in moving towards an integrated transport network for this region as a whole. The future opening of Myanmar route further gives some relief to India. Most of the cargo originates from Kolkata (Port) and terminates at Guwahati and distributed to various destinations of north eastern states. We try to investigate the pricing policy of such transhipment route for India in terms of a Bertrand type model with non homogeneous type cargo movement where the unit price of cargo transhipment taken as a proxy for such transhipment route

A fixed point formula for the index of multi-centered N=2 black holes

We propose a formula for computing the (moduli-dependent) contribution of multi-centered solutions to the total BPS index in terms of the (moduli-independent) indices associated to single-centered solutions. The main tool in our analysis is the computation of the refined index Tr(-y)^{2J_3} of configurational degrees of freedom of multi-centered BPS black hole solutions in N=2 supergravity by localization methods. When the charges carried by the centers do not allow for scaling solutions (i.e. solutions where a subset of the centers can come arbitrarily close to each other), the phase space of classical BPS solutions is compact and the refined index localizes to a finite set of isolated fixed points under rotations, corresponding to collinear solutions. When the charges allow for scaling solutions, the phase space is non-compact but appears to admit a compactification with finite volume and additional non-isolated fixed points. We give a prescription for determining the contributions of these fixed submanifolds by means of a `minimal modification hypothesis', which we prove in the special case of dipole halo configurations.Comment: 61 pages, 3 figure

Volkov solution for two laser beams and ITER

We find the solution of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an alectron. The practical meaning of the two laser beams is, that two laser beams impinging on a targed which is constituted from material in the form of a foam, can replace 100-200 laser beams impinging on a normal targed. It means that the nuclear fusion with two laser beams is realistic in combination with the nuclear reactor such as ITER.Comment: 13 page

Security and Privacy Issues in Wireless Mesh Networks: A Survey

This book chapter identifies various security threats in wireless mesh network (WMN). Keeping in mind the critical requirement of security and user privacy in WMNs, this chapter provides a comprehensive overview of various possible attacks on different layers of the communication protocol stack for WMNs and their corresponding defense mechanisms. First, it identifies the security vulnerabilities in the physical, link, network, transport, application layers. Furthermore, various possible attacks on the key management protocols, user authentication and access control protocols, and user privacy preservation protocols are presented. After enumerating various possible attacks, the chapter provides a detailed discussion on various existing security mechanisms and protocols to defend against and wherever possible prevent the possible attacks. Comparative analyses are also presented on the security schemes with regards to the cryptographic schemes used, key management strategies deployed, use of any trusted third party, computation and communication overhead involved etc. The chapter then presents a brief discussion on various trust management approaches for WMNs since trust and reputation-based schemes are increasingly becoming popular for enforcing security in wireless networks. A number of open problems in security and privacy issues for WMNs are subsequently discussed before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the author's previous submission in arXiv submission: arXiv:1102.1226. There are some text overlaps with the previous submissio

Logarithmic Corrections to N=2 Black Hole Entropy: An Infrared Window into the Microstates

Logarithmic corrections to the extremal black hole entropy can be computed purely in terms of the low energy data -- the spectrum of massless fields and their interaction. The demand of reproducing these corrections provides a strong constraint on any microscopic theory of quantum gravity that attempts to explain the black hole entropy. Using quantum entropy function formalism we compute logarithmic corrections to the entropy of half BPS black holes in N=2 supersymmetric string theories. Our results allow us to test various proposals for the measure in the OSV formula, and we find agreement with the measure proposed by Denef and Moore if we assume their result to be valid at weak topological string coupling. Our analysis also gives the logarithmic corrections to the entropy of extremal Reissner-Nordstrom black holes in ordinary Einstein-Maxwell theory.Comment: LaTeX file, 66 page

Reflection coefficient and localization length of waves in one-dimensional random media

We develop a novel and powerful method of exactly calculating various transport characteristics of waves in one-dimensional random media with (or without) coherent absorption or amplification. Using the method, we compute the probability densities of the reflectance and of the phase of the reflection coefficient, together with the localization length, of electromagnetic waves in sufficiently long random dielectric media. We find substantial differences between our exact results and the previous results obtained using the random phase approximation (RPA). The probabilty density of the phase of the reflection coefficient is highly nonuniform when either disorder or absorption (or amplification) is strong. The probability density of the reflectance when the absorption or amplification parameter is large is also quite different from the RPA result. We prove that the probability densities in the amplifying case are related to those in the absorbing case with the same magnitude of the imaginary part of the dielectric permeability by exact dual relationships. From the analysis of the average reflectance that shows a nonmonotonic dependence on the absorption or amplification parameter, we obtain a useful criterion for the applicability of the RPA. In the parameter regime where the RPA is invalid, we find the exact localization length is substantially larger than the RPA localization length.Comment: 16 pages, 9 figure