55 research outputs found

    Tsetse Salivary Gland Hypertrophy Virus: Hope or Hindrance for Tsetse Control?

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    Many species of tsetse flies (Diptera: Glossinidae) are infected with a virus that causes salivary gland hypertrophy (SGH), and flies with SGH symptoms have a reduced fecundity and fertility. The prevalence of SGH in wild tsetse populations is usually very low (0.2%–5%), but higher prevalence rates (15.2%) have been observed occasionally. The successful eradication of a Glossina austeni population from Unguja Island (Zanzibar) using an area-wide integrated pest management approach with a sterile insect technique (SIT) component (1994–1997) encouraged several African countries, including Ethiopia, to incorporate the SIT in their national tsetse control programs. A large facility to produce tsetse flies for SIT application in Ethiopia was inaugurated in 2007. To support this project, a Glossina pallidipes colony originating from Ethiopia was successfully established in 1996, but later up to 85% of adult flies displayed symptoms of SGH. As a result, the colony declined and became extinct by 2002. The difficulties experienced with the rearing of G. pallidipes, epitomized by the collapse of the G. pallidipes colony originating from Ethiopia, prompted the urgent need to develop management strategies for the salivary gland hypertrophy virus (SGHV) for this species. As a first step to identify suitable management strategies, the virus isolated from G. pallidipes (GpSGHV) was recently sequenced and research was initiated on virus transmission and pathology. Different approaches to prevent virus replication and its horizontal transmission during blood feeding have been proposed. These include the use of antiviral drugs such as acyclovir and valacyclovir added to the blood for feeding or the use of antibodies against SGHV virion proteins. In addition, preliminary attempts to silence the expression of an essential viral protein using RNA interference will be discussed

    The tearing instability of resistive magnetohydrodynamics

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    In this chapter we explore the linear onset of one of the most important instabilities of resistive magnetohydrodynamics, the tearing instability. In particular, we focus on two important aspects of the onset of tearing: asymptotic (modal) stability and transient (non-modal) stability. We discuss the theory required to understand these two aspects of stability, both of which have undergone significant development in recent years

    Nonlinear wave heating of the solar corona

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    3d nonlinear-wave heating of coronal loops

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    The heating of solar coronal loops by the resonant absorption or phase-mixing of incident wave energy is investigated in the framework of 3D nonlinear magnetohydrodynamics (MHD) by means of numerical simulations.status: publishe

    2D and 3D nonlinear MHD simulations of coronal loop heating by Alfven waves

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    Book subtitle: PROTOTYPES OF STELLAR MAGNETIC ACTIVITYstatus: publishe

    Coronal heating: the role of resonant absorption

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    Parallel magnetohydrodynamics on the Cray T3D

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    The equations of magnetohydrodynamics (MHD) are discussed in the framework of parallel computing. Both linear and nonlinear MHD models are addressed. Special attention is given to the parallellisation of the kernels of the existing sequential MHD codes. These kernels involve matrix-vector multiplications and dot products for the linear MHD calculations, and Fast Fourier Transforms and tri-diagonal systems solvers for the nonlinear MHD simulations.status: publishe

    Calculations of soft X-ray images from MHD simulations of heating of coronal loops

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    Book subtitle: PROTOTYPES OF STELLAR MAGNETIC ACTIVITYstatus: publishe

    Kink modes is coronal loops

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