one of the serious problems of iran’s watersheds is soil erosion and can be considered as one of the main obstacles to achieve sustainable agricultural development and natural resources. in most countries of the world, because of absence of accurate data for the sediment erosion, deposition utilizing models to estimate erosion is inevitable. in order to apply effective management in natural res...

We present the results of an experimental study on the transition to spiral vortices in flow between concentric counter-rotating cylinders in the presence of an axial through-flow, i.e., in spiral Poiseuille flow. The experiments were performed in an apparatus having an aspect ratio Gamma=L/d=22.8 ( L axial length, d gap width between cylinders) and end plates enabling an in and outflow of mass...

The nonlinear dynamics of Taylor-Couette flow in a small-aspect-ratio wide-gap annulus in the counterrotating regime is investigated by solving the full three-dimensional Navier-Stokes equations. The system is invariant under arbitrary rotations about the axis, reflection about the annulus midplane, and time translations. A systematic investigation is presented both in terms of the flow physics...

We study the linear instabilities and bifurcations in Selkov model for glycolysis with diffusion. show that this has a zero wave-vector, finite frequency Hopf bifurcation, which is forward or supercritical to growing oscillatory but spatially homogeneous state saddle-node backward subcritical inhomogeneous steady pattern characterised by wavevector. further demonstrate tuning relative diffusivi...

In this paper, a spatial tri-trophic food chain model with ratio-dependent Michaelis-Menten type functional response under homogeneous Neumann boundary conditions is studied. Conditions for Hopf and Turing bifurcation are derived. Sufficient conditions for the emergence of spatial patterns are obtained. The results of numerical simulations reveal the formation of labyrinth patterns and the coex...

OBJECTIVES We aimed to assess the associations of stenting strategy and bifurcation anatomy with outcomes of percutaneous coronary intervention (PCI) for distal unprotected left main (ULM) coronary disease. BACKGROUND There are limited and conflicting data regarding long-term outcomes associated with stenting strategies for PCI of distal ULM coronary disease. METHODS Patients undergoing non...

OBJECTIVE To investigate the morphological and hemodynamic parameters associated with middle cerebral artery (MCA)bifurcation aneurysm rupture. METHODS A retrospective study of 67 consecutive patients was carried out based on 3D digital subtraction angiography data. Morphological and hemodynamic parameters including aneurysm size parameters (dome width, height, and perpendicular height), long...

This paper deals with a delayed ratio-dependent functional response predator-prey model with a threshold harvesting policy. We study the equilibria of the system before and after the threshold. We show that the threshold harvesting can improve the undesirable behavior such as nonexistence of interior equilibria. The global analysis of the model as well as boundedness and permanence properties a...

At the end of Sect. 2.2 I state that, as input current I increases, the first Hopf bifurcation 3 occurring in the Fitzhugh-Nagumo (FN) equation is supercritical. This is incorrect. 4 For neurally-relevant values of the time constant ratio τv/τr ! 1, it is subcritical and 5 is preceded by a saddle-node bifurcation in which the stable limit cycle and an unstable 6 cycle appear, as in the full Hod...

BACKGROUND AND PURPOSE The choice of the experimental aneurysm model is essential for valid embolization-device evaluations. So far, the use of the rabbit venous pouch arterial bifurcation aneurysm model has been limited by demanding microsurgery, low aneurysm patency rates, and high mortality. This study aimed to facilitate microsurgery and to reduce mortality by optimized peri-/postoperative ...