In this paper, we consider spatial predator-prey models with diffusion and prey-taxis. We investigate necessary conditions for pattern formation using a variety of non-linear functional responses, linear and non-linear predator death terms, linear and non-linear prey-taxis sensitivities, and logistic growth or growth with an Allee effect for the prey. We identify combinations of the above non-l...

We report on the experimental observation of speckle formation from a transparent crystal formed by a random distribution of nonlinear domains. The angular distribution of second-harmonic light generated by a transparent strontium barium niobate crystal is measured for different diameters of the fundamental beam and crystal thicknesses. Distinct manifestations of speckle pattern formation are f...

The effects of non-equilibrium charge screening in mixtures of oppositely charged interacting molecules on surfaces are analyzed in a closed system. The dynamics of charge screening and the strong deviation from the standard Debye-Hückel theory are demonstrated via a new formalism based on computing radial distribution functions suited for analyzing both short-range and long-range spacial order...

We present an experimental and theoretical investigation of spontaneous pattern formation in the transverse section of a single retroreflected laser beam passing through a cloud of cold rubidium atoms. In contrast to previously investigated systems, the nonlinearity at work here is that of a two-level atom, which realizes the paradigmatic situation considered in many theoretical studies of opti...

Background: Patients who undergo major orthopedic surgery are at risk of acute kidney injury (AKI) due to blood loss, electrolyte disorders, infection, and the presence of other co-morbidities. In this study, the frequency and risk factors of AKI were investigated. Objective & Methods: This study is a cross-sectional-analytical study with a sample size of 180 people. The studied population wer...

the aim of this study is to find causes of cardiac disrhytmias during ophthalmic surgeries in patients under general anesthesia with no history of heart disease in iran’s educational hospitals. this was a univarient study. a sample of 250 patients selected randomly. data were gathered by four resources: interview, patient’s documents, kind of treatment selected by anesthesiologist and monitorin...