617 research outputs found

    Chaotic synchronization of coupled electron-wave systems with backward waves

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    The chaotic synchronization of two electron-wave media with interacting backward waves and cubic phase nonlinearity is investigated in the paper. To detect the chaotic synchronization regime we use a new approach, the so-called time scale synchronization [Chaos, 14 (3) 603-610 (2004)]. This approach is based on the consideration of the infinite set of chaotic signals' phases introduced by means of continuous wavelet transform. The complex space-time dynamics of the active media and mechanisms of the time scale synchronization appearance are considered.Comment: 11 pages, 7 figures, published in CHAOS, 15 (2005) 01370

    Self-tuning of threshold for a two-state system

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    A two-state system (TSS) under time-periodic perturbations (to be regarded as input signals) is studied in connection with self-tuning (ST) of threshold and stochastic resonance (SR). By ST, we observe the improvement of signal-to-noise ratio (SNR) in a weak noise region. Analytic approach to a tuning equation reveals that SNR improvement is possible also for a large noise region and this is demonstrated by Monte Carlo simulations of hopping processes in a TSS. ST and SR are discussed from a little more physical point of energy transfer (dissipation) rate, which behaves in a similar way as SNR. Finally ST is considered briefly for a double-well potential system (DWPS), which is closely related to the TSS

    Two Scenarios of Breaking Chaotic Phase Synchronization

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    Two types of phase synchronization (accordingly, two scenarios of breaking phase synchronization) between coupled stochastic oscillators are shown to exist depending on the discrepancy between the control parameters of interacting oscillators, as in the case of classical synchronization of periodic oscillators. If interacting stochastic oscillators are weakly detuned, the phase coherency of the attractors persists when phase synchronization breaks. Conversely, if the control parameters differ considerably, the chaotic attractor becomes phase-incoherent under the conditions of phase synchronization break.Comment: 8 pages, 7 figure

    Engineered single nucleotide polymorphisms in the mosquito MEK docking site alter Plasmodium berghei development in Anopheles gambiae.

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    BackgroundSusceptibility to Plasmodium infection in Anopheles gambiae has been proposed to result from naturally occurring polymorphisms that alter the strength of endogenous innate defenses. Despite the fact that some of these mutations are known to introduce non-synonymous substitutions in coding sequences, these mutations have largely been used to rationalize knockdown of associated target proteins to query the effects on parasite development in the mosquito host. Here, we assay the effects of engineered mutations on an immune signaling protein target that is known to control parasite sporogonic development. By this proof-of-principle work, we have established that naturally occurring mutations can be queried for their effects on mosquito protein function and on parasite development and that this important signaling pathway can be genetically manipulated to enhance mosquito resistance.MethodsWe introduced SNPs into the A. gambiae MAPK kinase MEK to alter key residues in the N-terminal docking site (D-site), thus interfering with its ability to interact with the downstream kinase target ERK. ERK phosphorylation levels in vitro and in vivo were evaluated to confirm the effects of MEK D-site mutations. In addition, overexpression of various MEK D-site alleles was used to assess P. berghei infection in A. gambiae.ResultsThe MEK D-site contains conserved lysine residues predicted to mediate protein-protein interaction with ERK. As anticipated, each of the D-site mutations (K3M, K6M) suppressed ERK phosphorylation and this inhibition was significant when both mutations were present. Tissue-targeted overexpression of alleles encoding MEK D-site polymorphisms resulted in reduced ERK phosphorylation in the midgut of A. gambiae. Furthermore, as expected, inhibition of MEK-ERK signaling due to D-site mutations resulted in reduction in P. berghei development relative to infection in the presence of overexpressed catalytically active MEK.ConclusionMEK-ERK signaling in A. gambiae, as in model organisms and humans, depends on the integrity of conserved key residues within the MEK D-site. Disruption of signal transmission via engineered SNPs provides a purposeful proof-of-principle model for the study of naturally occurring mutations that may be associated with mosquito resistance to parasite infection as well as an alternative genetic basis for manipulation of this important immune signaling pathway

    Synchronization of chaotic oscillator time scales

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    This paper deals with the chaotic oscillator synchronization. A new approach to detect the synchronized behaviour of chaotic oscillators has been proposed. This approach is based on the analysis of different time scales in the time series generated by the coupled chaotic oscillators. It has been shown that complete synchronization, phase synchronization, lag synchronization and generalized synchronization are the particular cases of the synchronized behavior called as "time--scale synchronization". The quantitative measure of chaotic oscillator synchronous behavior has been proposed. This approach has been applied for the coupled Rossler systems.Comment: 29 pages, 11 figures, published in JETP. 100, 4 (2005) 784-79

    Legal problems of the corruption prevention in state and municipal health care institutions

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    The purpose of the research: to investigate the problems of legal regulation of the corruption prevention in health care institutions, outline ways of their solution. Materials and methods: normative-legal base of Ukraine, method of analysis, method of synthesis, comparative-legal method. Results: The issues of the corruption prevention, including its prevention in health care institutions, are regulated by a number of normative legal acts, in particular the Law of Ukraine "About Corruption Prevention", the Code of Ukraine on Administrative Offenses, and the Criminal Code of Ukraine. However, a number of norms are collisional, therefore they need legal improvement. Conclusions: One of the main problems of the corruption prevention is the formation of a unified normative approach to the legal regulation of the health care institutions financing, which is to bring in compliance all other normative legal acts regulating these issues with the Constitution of Ukraine or changing the Constitution. The requirements of the Criminal Code of Ukraine, the Labor Code of Ukraine, and the Civil Code of Ukraine require alignment with the Law of Ukraine "About Corruption Prevention". It is necessary to legislatively define mechanisms for the protection of the rights of officials, in particular the right to extract information about a person from the Unified State Register of persons who committed corruption or corruption-related offenses in the event of the expiration of the period provided for by the Code of Ukraine on Administrative Offenses and the Labor Code of Ukraine after the end of which the person is considered to be not attracted to a certain type of responsibility. The urgent need is to increase social standards for health workers. The need for significant improvement of the notion and settlement of the conflict of interests in accordance with the current legislation is dictated by the threat of bringing this legal institution to the point of absurdity. And, of course, strengthening legal education and legal work with patients and health care providers, maximizing the openness of information is an effective prevention of corruption manifestations
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