1,091 research outputs found

    The Scale Invariant Wigner Spectrum Estimation of Gaussian Locally Self-Similar Processes

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    We study locally self-similar processes (LSSPs) in Silverman's sense. By deriving the minimum mean-square optimal kernel within Cohen's class counterpart of time-frequency representations, we obtain an optimal estimation for the scale invariant Wigner spectrum (SIWS) of Gaussian LSSPs. The class of estimators is completely characterized in terms of kernels, so the optimal kernel minimizes the mean-square error of the estimation. We obtain the SIWS estimation for two cases: global and local, where in the local case, the kernel is allowed to vary with time and frequency. We also introduce two generalizations of LSSPs: the locally self-similar chrip process and the multicomponent locally self-similar process, and obtain their optimal kernels. Finally, the performance and accuracy of the estimation is studied via simulation.Comment: 28 page

    Application of predictive degree day model for field development of sandfly vectors of visceral leishmaniasis in northwest of Iran

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    Background & objectives: Temperature plays a significant role in insect’s development where arise in temperature, accelerates the insect’s metabolic rates, increases egg production and makesblood feeding more frequent. It also shortens the time period required for the development ofpathogens within insects. Visceral leishmaniasis (VL) is one of the most important vector-bornediseases transmitted by different sandfly species. In this study, a phenological model was used toestimate the number of generations, peak activity and temporal variability of sandflies in the mainVL foci in northwest Iran.Methods: Development requirements of different life stages of a Phlebotomus papatasi laboratorycolony were measured and were subjected to the formula for calculation of accumulated degree day(ADD) for field sandflies using the online soft (UC IPM), using horizontal cut-off method andsingle triangle model. Sandflies population dynamics was monitored in the field during the seasonalactivity in the region and its association with the ADD was tested using SAS software.Results: Populations of sandflies accommodated well with the amount of accumulated degree days(ADD) in the region. During the seasonal activity, a total of 639 ADD were produced which wasenough to support one complete life cycle and growth of the next generation up to late larvalinstar. Larvae of the second generation hibernate through winter and the first adult populationappears in the mid to late June of the next year when they receive at least 182 ADD from thebeginning of the spring. The highest population density of sandflies was observed in early August,followed by a rapid decrease in early September, with the adult population disappearing completelyin late September. This is the first degree day model related to sandflies in the most important VLfoci of Iran.Interpretation & conclusion: Further studies in various regions with variable climate arerecommended in order to better estimate and understand the development time, population dynamicsand activities of the vectors which in turn could be used in proper implementation of effectivevector control programmes

    Generalized Grassmannian Coherent States For Pseudo-Hermitian nn Level Systems

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    The purpose of this paper is to generalize fermionic coherent states for two-level systems described by pseudo-Hermitian Hamiltonian \cite{Trifonov}, to n-level systems. Central to this task is the expression of the coherent states in terms of generalized Grassmann variables. These kind of Grassmann coherent states satisfy bi-overcompleteness condition instead of over-completeness one, as it is reasonably expected because of the biorthonormality of the system. Choosing an appropriate Grassmann weight function resolution of identity is examined. Moreover Grassmannian coherent and squeezed states of deformed group SUq(2)SU_{q}(2) for three level pseudo-Hermitian system are presented.Comment: 17 page

    Maximal Entanglement of Two-qubit States Constructed by Linearly Independent Coherent States

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    In this paper, we find the necessary and sufficient condition for the maximal entanglement of the state, ψ>=μα>β>+λα>δ>+ργ>β>+νγ>δ>, |\psi>=\mu|\alpha>|\beta>+\lambda|\alpha>|\delta>+ \rho|\gamma>|\beta>+\nu|\gamma>|\delta>, constructed by linearly independent coherent states with \emph{real parameters} when ==. This is a further generalization of the classified nonorthogonal states discussed in Ref. Physics Letters A {\bf{291}}, 73-76 (2001).Comment: some examples added; Int J Theor Phys 201

    Selective reporting: a half signalling load algorithm for distributed sensing

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    Spectrum sensing is a powerful tool of the cognitive cycle to help circumvent the apparent spectrum scarcity faced by wireless transmission systems. To overcome the challenging issues faced by the localized sensing, multiple cognitive radios can cooperate to explore the multiuser diversity and generate a more reliable decision on the presence of a signal in the frequencies of interest. In such a cooperative sensing scenario, a common reporting channel is needed for the transmission of the information of each element. As the number of elements that participate in the sensing operation increases, so does the bandwidth demanded for the reporting channel, quickly becoming the limiting factor in this scenario. To tackle the issue of reducing the sensing report overhead, this paper introduces a new cooperative sensing scheme that introduces silence periods in the reporting and, relying on information theory principles, explores the information present in these periods to reduce by 50% the sensing reporting overhead while maintaining the same performance of standard reporting schemes. Numerical and experimental results confirm the theoretical analysis and show the predicted reduction in reporting overhead and performance preservation

    Treatment of Noninfectious Retinal Vasculitis Using Subcutaneous Repository Corticotropin Injection

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    Purpose: To show whether subcutaneous repository corticotropin injection (RCI, Acthar® Gel, a repository corticotropin injection, can be an effective potential therapeutic agent for noninfectious retinal vasculitis. Methods: Patients with active retinal vasculitis were followed with serial ultra-widefield fluorescein angiograms and treated with 80 units of subcutaneous repository corticotropin injection twice weekly. Results: Primary outcome of ≥50% improvement in response level (RL) for retinal vasculitis and percent improvement in retinal vasculitis severity scoring (RVSS) by more than one quartile (≥25%) at week 12 was met in 15 and 16 of the 30 total eyes, respectively, including 1 eye with severe retinal vasculitis in each group. Complete resolution of retinal vasculitis was seen in seven eyes with a mean time of 17.1 weeks. Intraocular pressure elevation requiring therapy and cataract progression were noted in two and three eyes, respectively. One patient stopped medication due to side effects (injection site reaction). Conclusion: Repository corticotropin injection was well-tolerated overall. Repository corticotropin injection may be an effective therapeutic agent in the treatment of noninfectious retinal vasculitis
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