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...

RECENTL Y we reported that. in human liver transplantation, a preservation period of greater than 20 hours caused the rate of graft failure to increase nonlinearly.l Even with University of Wisconsin (UW) solution. there is a finite limit to the permissible time of cold storage of livers. In this study, we investigated whether microcirculatory disturbance during and after preservation is correl...

OBJECTIVE To examine ethnic differences in observed parenting and child behavior and the moderating effects of ethnicity on the relationship between treatment and parent and child behavior. METHOD Observations of 508 children with ADHD (ages 7-9) and their caregivers, collected during the Multimodal Treatment Study of ADHD, were analyzed using univariate and mixed-model ANOVAs. RESULTS Alth...

U M LTIORGAN harvesting for individual organ transplantation is well defined according to the principles of Starzl. However, some pancreatic transplant surgeons believe the pancreas should not suffer hyperperfusion as occurs in multiorgan harvesting. This is in conflict with the need of all donor organs for transplantation and specially when multivisceral transplantation is planned. We believe ...

We apply a single Boltzmann-like integro-diierential equation to model pattern formation in aspect space. Dynamics of density distributions are considered in two cases. First, the distribution of organisms on the real line is investigated. A linear stability analysis reveals conditions on interactions between the organisms that lead to aggregation and periodic patterns. Use of diiusion approxim...