The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform

Marija Krstic - One of the best experts on this subject based on the ideXlab platform.

  • stochastically perturbed vector borne disease models with Direct Transmission
    Applied Mathematical Modelling, 2012
    Co-Authors: Miljana Jovanovic, Marija Krstic
    Abstract:

    Abstract In this paper we study a stochastic epidemic model of vector-borne diseases with Direct mode of Transmission and its delay modification. More precisely, we extend the deterministic epidemic models by introducing random perturbations around the endemic equilibrium state. By using suitable Lyapunov functions and functionals, we obtain stability conditions for the considered models and study the effect of the delay on the stability of the endemic equilibrium. Finally, numerical simulations for the stochastic model of malaria disease Transmission are presented to illustrate our mathematical findings.

Kazuhiro Tobe - One of the best experts on this subject based on the ideXlab platform.

  • Phenomenological aspects of a Direct-Transmission model of dynamical supersymmetry breaking with the gravitino mass m 3 / 2 1 keV
    Physical Review D, 1998
    Co-Authors: Yasunori Nomura, Kazuhiro Tobe
    Abstract:

    We analyze a Direct-Transmission model of dynamical supersymmetry breaking previously proposed. In the model the gravitino mass is naturally smaller than $1 \mathrm{keV},$ which is required from standard cosmology. We find that there are many distinguishable features with other models: for example the so-called GUT relation among the gaugino masses does not hold even if we consider the GUT models. Furthermore, the gauginos are always lighter than the sfermions since the gaugino masses have extra suppression factors. We also discuss a collider signature ``$\ensuremath{\gamma}\ensuremath{\gamma}+$ missing energy'' in the present model.

  • Direct-Transmission models of dynamical supersymmetry breaking
    Physical Review D, 1997
    Co-Authors: Ken-iti Izawa, Yasunori Nomura, Kazuhiro Tobe, T. Yanagida
    Abstract:

    We systematically construct gauge-mediated supersymmetry- (SUSY-) breaking models with Direct Transmission of SUSY-breaking effects to the standard-model sector. We obtain a natural model with the gravitino mass m{sub 3/2} smaller than 1 keV as required from the standard cosmology. If all Yukawa coupling constants are of order one, the SUSY-breaking scale m{sub SUSY} transmitted into the standard-model sector is given by m{sub SUSY}{approx_equal}0.1({alpha}{sub i}/4{pi}){Lambda} where {Lambda} is the original dynamical SUSY-breaking scale. Imposing m{sub SUSY}{approx_equal}(10{sup 2}{endash}10{sup 3}) GeV, we get {Lambda}{approx_equal}(10{sup 5}{endash}10{sup 6}) GeV, which yields the gravitino mass m{sub 3/2}{approx_equal}(10{sup {minus}2}{endash}1) keV. {copyright} {ital 1997} {ital The American Physical Society}

Miljana Jovanovic - One of the best experts on this subject based on the ideXlab platform.

  • stochastically perturbed vector borne disease models with Direct Transmission
    Applied Mathematical Modelling, 2012
    Co-Authors: Miljana Jovanovic, Marija Krstic
    Abstract:

    Abstract In this paper we study a stochastic epidemic model of vector-borne diseases with Direct mode of Transmission and its delay modification. More precisely, we extend the deterministic epidemic models by introducing random perturbations around the endemic equilibrium state. By using suitable Lyapunov functions and functionals, we obtain stability conditions for the considered models and study the effect of the delay on the stability of the endemic equilibrium. Finally, numerical simulations for the stochastic model of malaria disease Transmission are presented to illustrate our mathematical findings.

Dawit Denu - One of the best experts on this subject based on the ideXlab platform.

  • existence of traveling wave solutions of a deterministic vector host epidemic model with Direct Transmission
    Journal of Mathematical Analysis and Applications, 2020
    Co-Authors: Dawit Denu, Sedar Ngoma, Rachidi B Salako
    Abstract:

    Abstract We consider an epidemic model with Direct Transmission given by a system of nonlinear partial differential equations and study the existence of traveling wave solutions. When the basic reproductive number of the considered model is less than one, we show that there is no nontrivial traveling wave solution. On the other hand, when the basic reproductive number is greater than one, we prove that there is a minimum wave speed c ⁎ such that the system has a traveling wave solution with speed c connecting both equilibrium points for any c ≥ c ⁎ . Moreover, under suitable assumption on the diffusion rates, we show that there is no traveling wave solution with speed less than c ⁎ . We conclude with numerical simulations to illustrate our findings. The numerical experiments support the validity of our theoretical results.

  • Existence of traveling wave solutions of a deterministic vector-host epidemic model with Direct Transmission
    arXiv: Analysis of PDEs, 2019
    Co-Authors: Dawit Denu, Sedar Ngoma, Rachidi B Salako
    Abstract:

    We consider an epidemic model with Direct Transmission given by a system of nonlinear partial differential equations and study the existence of traveling wave solutions. When the basic reproductive number of the considered model is less than one, we show that there is no nontrivial traveling wave solution. On the other hand, when the basic reproductive number is greater than one, we prove that there is a minimum wave speed $c^*$ such that the system has a traveling wave solution with speed $c$ connecting both equilibrium points for any $c\ge c^*$. Moreover, under suitable assumption on the diffusion rates, we show that there is no traveling wave solution with speed less than $c^*$. We conclude with numerical simulations to illustrate our findings. The numerical experiments supports the validity of our theoretical results.

  • Analysis of stochastic vector-host epidemic model with Direct Transmission
    Discrete and Continuous Dynamical Systems - Series B, 2016
    Co-Authors: Yanzhao Cao, Dawit Denu
    Abstract:

    In this paper, we consider the stochastic vector-host epidemic model with Direct Transmission. First, we study the existence of a positive global solution and stochastic boundedness of the system of stochastic differential equations which describes the model. Then we introduce the basic reproductive number $\mathcal{R}^s_0$ in the stochastic model, which reflects the deterministic counterpart, and investigate the dynamics of the stochastic epidemic model when $\mathcal{R}^s_0 1$. In particular, we show that random effects may lead to extinction in the stochastic case while the deterministic model predicts persistence. Additionally, we provide conditions for the extinction of the infection and stochastic stability of the solution. Finally, numerical simulations are presented to illustrate some of the theoretical results.

Yasunori Nomura - One of the best experts on this subject based on the ideXlab platform.

  • Phenomenological aspects of a Direct-Transmission model of dynamical supersymmetry breaking with the gravitino mass m 3 / 2 1 keV
    Physical Review D, 1998
    Co-Authors: Yasunori Nomura, Kazuhiro Tobe
    Abstract:

    We analyze a Direct-Transmission model of dynamical supersymmetry breaking previously proposed. In the model the gravitino mass is naturally smaller than $1 \mathrm{keV},$ which is required from standard cosmology. We find that there are many distinguishable features with other models: for example the so-called GUT relation among the gaugino masses does not hold even if we consider the GUT models. Furthermore, the gauginos are always lighter than the sfermions since the gaugino masses have extra suppression factors. We also discuss a collider signature ``$\ensuremath{\gamma}\ensuremath{\gamma}+$ missing energy'' in the present model.

  • Direct-Transmission models of dynamical supersymmetry breaking
    Physical Review D, 1997
    Co-Authors: Ken-iti Izawa, Yasunori Nomura, Kazuhiro Tobe, T. Yanagida
    Abstract:

    We systematically construct gauge-mediated supersymmetry- (SUSY-) breaking models with Direct Transmission of SUSY-breaking effects to the standard-model sector. We obtain a natural model with the gravitino mass m{sub 3/2} smaller than 1 keV as required from the standard cosmology. If all Yukawa coupling constants are of order one, the SUSY-breaking scale m{sub SUSY} transmitted into the standard-model sector is given by m{sub SUSY}{approx_equal}0.1({alpha}{sub i}/4{pi}){Lambda} where {Lambda} is the original dynamical SUSY-breaking scale. Imposing m{sub SUSY}{approx_equal}(10{sup 2}{endash}10{sup 3}) GeV, we get {Lambda}{approx_equal}(10{sup 5}{endash}10{sup 6}) GeV, which yields the gravitino mass m{sub 3/2}{approx_equal}(10{sup {minus}2}{endash}1) keV. {copyright} {ital 1997} {ital The American Physical Society}