Influenza viruses belong to the family Orthomyxoviridae with a negative-sense, single-stranded segmented RNA genome. They infect a wide range of animals, including humans. From 1918 to 2009, there were four influenza pandemics, which caused millions of casualties. Frequent spillover of animal influenza viruses to humans with or without intermediate hosts poses a serious zoonotic and pandemic threat. The current SARS-CoV-2 pandemic overshadowed the high risk raised by animal influenza viruses, but highlighted the role of wildlife as a reservoir for pandemic viruses. In this review, we summarize the occurrence of animal influenza virus in humans and describe potential mixing vessel or intermediate hosts for zoonotic influenza viruses. While several animal influenza viruses possess a high zoonotic risk (e.g., avian and swine influenza viruses), others are of low to negligible zoonotic potential (e.g., equine, canine, bat and bovine influenza viruses). Transmission can occur directly from animals, particularly poultry and swine, to humans or through reassortant viruses in “mixing vessel” hosts. To date, there are less than 3000 confirmed human infections with avian-origin viruses and less than 7000 subclinical infections documented. Likewise, only a few hundreds of confirmed human cases caused by swine influenza viruses have been reported. Pigs are the historic mixing vessel host for the generation of zoonotic influenza viruses due to the expression of both avian-type and human-type receptors. Nevertheless, there are a number of hosts which carry both types of receptors and can act as a potential mixing vessel host. High vigilance is warranted to prevent the next pandemic caused by animal influenza viruses.
We discuss a methodology that could be gainfully exploited using easily measurable experimental quantities to ascertain if the ``no-slip" boundary condition is appropriate for the flows of fluids past a solid boundary.
In this paper, flows of a viscid fluids on curves are considered. Symmetry algebras and the corresponding fields of differential invariants are found. We study their dependence on thermodynamic states of media, and provide classification of thermodynamic states.
These notes are based on some lectures that the author gave at the University of Campinas - UNICAMP. The notes are in Portuguese, and deal with some methods of mathematics applied to Fluid Mechanics.
In every turbulent flow with non-zero viscosity, heat is generated by viscous friction. This heat is then mixed by the velocity field. We consider how heat fluctuations generated this way are injected and distributed over length scales in isotropic turbulence. A triadic closure is derived and numerically integrated. It is shown how the heat fluctuation spectrum depends on the Reynolds and Prandtl numbers.
In this final note we demonstrate that the authors of manuscripts arXiv:1210.2036, arXiv:1309.0405 and arXiv:1309.5513 use mathematical notations and notions sometimes in the standard meaning and sometimes in a sense which differs from the standard. As this specific use is not defined beforehand, the authors' statements are self-contradictory which makes any further scientific discussion meaningless.
We discuss the scaling laws for the flow generated in a viscous fluid by a wave propagating along a solid boundary. This has applications to the displacement of tiny objects on solids, under the effect of progressive surface waves and for the swimming of microanimals by undulation of ciliae along their body surface.
Wojcik's hypothesis has been mentioned on page 32 of the text S.Piekarski, "Galilean-Invariant Formulation of the Fluid Mechanics", IFTR REPORTS, 7/2007. Here we discuss it in more detail. Our main is to show that the form of the restrictions imposed by the Gibbs identity can depend on the choice of coordinates. The possible reactions for this unpleasant fact are shortly discused
A fluid dynamics video of the rotating, weakly stratified Boussinesq equations is presented that illustrates the spontaneous formation of columnar vortices in the presence of stochastic, white noise forcing.
Philipp A. Boettcher, Brian Ventura, Joseph E. Shepherd
Hot surface ignition and subsequent flame propagation of premixed n-hexane air mixtures are shown in this fluid dynamics video. High speed schlieren photography revealed 3 distinct behaviors of ignition and propagation as a function of mixture composition and initial pressure.
It is shown that, for stationary isotropic turbulence, Taylor's well known surrogate for the dissipation can be derived directly from the Karman-Howarth equation and is in fact a surrogate for inertial transfer, which becomes equal to the dissipation rate as the Reynolds number tends to infinity.
We consider special solution to the 3D compressible Navier-Stokes system with and without the Coriolis force and dry friction and find the respective initial data implying a finite time gradient catastrophe.
It is shown that in a rotating compressible fluid the resonant frequencies (measured in a system of reference rotating together with the medium) for the azimuthally running acoustic waves are split into two components. The received results can be of practical significance as a basis of a method of measurements of angular speed of medium and for acoustics of rotating technical devices.
The Monte Carlo simulation of $N$ point vortices with square periodic boundary conditions is performed where $N$ is order of 100. The clustering property is examined by computing the $L$ function familiar in the field of spatial ecology. The case of a positive value of $L$ corresponds to the state of clustering and the Onsager's negative temperature.