background: spine of an adult is made up of five areas that include 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, sacrum and finally coccyx. selecting appropriate assumptions for modeling and biological analysis of the spine components has a significant impact on the accuracy of results in biomechanical simulation for different modes. methods: in the present study, biomechani...

The main goal of this paper is to study the maximum number of limit cycles that bifurcate from the period annulus of the cubic centers that have a rational first integral of degree 2 when they are perturbed inside the class of all cubic polynomial differential systems using the averaging theory. The computations of this work have been made with Mathematica and Maple.

laminar mixed convection of aluminium oxide (al2o3)–water nanofluid flow in an inclined annulus using a single-phase approach was numerically studied. constant heat flux boundary conditions were applied on the inner and outer walls. all the thermophysical properties of nanofluid, such as, viscosity, heat capacity, thermal conductivity, and thermal expansion coefficient, except density in the bo...

An annulus SLEκ trace tends to a single point on the target circle, and the density function of the end point satisfies some differential equation. Some martingales or local martingales are found for annulus SLE4, SLE8 and SLE8/3. From the local martingale for annulus SLE4 we find a candidate of discrete lattice model that may have annulus SLE4 as its scaling limit. The local martingale for ann...

background: sickle-cell disease (scd) is an inherited hemoglobin childhood disorder, frequently complicated by pulmonary hypertension and cardiac involvement. cardiovascular events and complications are the leading cause of mortality and morbidity in patients with scd. tissue doppler imaging and the myocardial performance index (tei index), are simple indices for the assessment of the cardiac f...

We give sufficient conditions in terms of the Melnikov functions in order that an analytic or a polynomial differential system in the real plane has a period annulus. We study the first nonzero Melnikov function of the analytic differential systems in the real plane obtained by perturbing a Hamiltonian system having either a nondegenerate center, a heteroclinic cycle, a homoclinic cycle, or thr...

We suggest a fiber micro-knot fabricated on a long-period fiber grating. The long-period fiber grating excites high-order modes into the micro-knot and transfers the output back to the Gaussian mode. We show theoretically and experimentally that these micro-knots have an improved Q-factor, higher stability, and have an increased evanescence wave coupling to the environment than single mode fibe...