This study presents a discrete-time model for the effects of selection and immigration on the demographic and genetic compositions of a population. Under biologically reasonable conditions, it is shown that the model always has an equilibrium. Although equilibria for similar models without migration must have real eigenvalues, for this selection-migration model we illustrate a Hopf bifurcation ...

Attenuation in seismic wave propagation is a common cause for poor illumination of subsurface structures. Attempts to compensate for amplitude loss in seismic images by amplifying the wavefield may boost high-frequency components and create undesirable imaging artifacts. In this paper, rather than amplifying the wavefield directly, we develop a stable compensation operator using smooth division...

Abstract Migration between countries is not a fresh problem; it has occurred since the dawn of time, but little research been conducted on it, particularly by employing effective technologies such as Geographic Information Systems (GIS). As result, purpose this paper was to investigate migration Sudanese other and vice versa, well students higher education from Sudan countries. To study all thi...

The migration of packaging material constituents into food is a product of the interaction between the food and packaging material. This phenomenon is of importance because some migrating substances may be toxicologically carcinogenic and endanger the consumer safety. Polystyrenes are used in many food-contact applications for the packaging of aqueous-based, fatty and dry foods. The correlation...

Background and Objectives: The addition of plasticizers (mainly phthalates and adipates) makes plastic flexible and popular for packaging, storing and preserving food, water, and so on. The most widely used plasticizer in food contact applications is di-ethylhexyl phthalate (DEHP) though being suspected to have carcinogenic and estrogenic properties. The aim of this study is application of magn...

Impairments in cell migration processes may cause various diseases, among which cancer cell metastasis, tumor angiogenesis, and the disability of immune cells to infiltrate into tumors are prominent ones. Mathematical modeling has been widely used to analyze the cell migration process. Cell migration is a complicated process and requires statistical methods such as random walk for proper analys...

Optimal migration theory suggests specific scaling relationships between body size and migration speed for individual birds based on the minimization of time, energy, and risk. Here we test if the quantitative predictions originating from this theory can be detected when migration decisions are integrated across individuals. We estimated population-level migration trajectories and daily migrati...

T cell activation is based on interactions of T cell antigen receptors with MHC-peptide complexes in a specialized cell-cell junction between the T cell and antigen-presenting cell-the immunological synapse. The immunological synapse coordinates naïve T cell activation and migration by stopping T cell migration with antigen-presenting cells bearing appropriate major histocompatibility complex (...