Three-dimensional random walk models of individual animal movement and their application to trap counts modelling.

BACKGROUND: Random walks (RWs) have proved to be a powerful modelling tool in ecology, particularly in the study of animal movement. An application of RW concerns trapping which is the predominant sampling method to date in insect ecology and agricultural pest management. A lot of research effort has been directed towards modelling ground-dwelling insects by simulating their movement in 2D, and computing pitfall trap counts, but comparatively very little for flying insects with 3D elevated traps. METHODS: We introduce the mathematics behind 3D RWs and present key metrics such as the mean squared displacement (MSD) and path sinuosity, which are already well known in 2D. We develop the mathematical theory behind the 3D correlated random walk (CRW) which involves short-term directional persistence and the 3D Biased random walk (BRW) which introduces a long-term directional bias in the movement so that there is an overall preferred movement direction. In this study, we focus on the geometrical aspects of the 3D trap and thus consider three types of shape; a spheroidal trap, a cylindrical trap and a rectangular cuboidal trap. By simulating movement in 3D space, we investigated the effect of 3D trap shapes and sizes and of movement diffusion on trapping efficiency. RESULTS: We found that there is a non-linear dependence of trap counts on the trap surface area or volume, but the effect of volume appeared to be a simple consequence of changes in area. Nevertheless, there is a slight but clear hierarchy of trap shapes in terms of capture efficiency, with the spheroidal trap retaining more counts than a cylinder, followed by the cuboidal type for a given area. We also showed that there is no effect of short-term persistence when diffusion is kept constant, but trap counts significantly decrease with increasing diffusion. CONCLUSION: Our results provide a better understanding of the interplay between the movement pattern, trap geometry and impacts on trapping efficiency, which leads to improved trap count interpretations, and more broadly, has implications for spatial ecology and population dynamics.

Limb regeneration in salamanders and digital tip regeneration in experimental mice: implications for the hand surgeon.

UNLABELLED: Several lessons and observations from limb regeneration in animals could open new insights to direct related research in the field of hand surgery. This article briefly reviews the biology of limb regeneration in salamanders and experimental mice, with special emphasis on implications for hand surgery. LEVEL OF EVIDENCE: 5.

Effect of vaccination on expression of intracellular adhesion molecules 1 and vascular cell adhesion molecules 1 in murine schistosomiasis.

This work studied the approach of vaccination by utilizing ultraviolet attenuated S. mansoni cercariae on two surface adhesion molecules expression, intercellular adhesion molecules 1 (ICAM-1) and vascular cell adhesion molecules 1(VCAM-1). ICAM-1 and VCAM-1 expression were studied in livers of 37 CD-1 female mice (2 months aged and about 30 gm waited) which were divided into 3 groups. Analysis of adhesion molecules expression was done by direct immunofluorescence staining and quantitative measurement of positive signals by image analyzer. The main findings were: (1) ICAM-1 and VCAM-1 expression was mainly localized on granuloma cells. (2) The video count areas that expressed ICAM-1 and VCAM-1 were markedly increased in vaccinated than naive animals. The ICAM-1 intensity was (58.7%) in VC while (31.1%) in NC mice group. (3) Similarly the intensity of VCAM-1 expression was (73%) In VC while (54.2%) in NC. (4) The % change in ICAM-I expression relative to naive mice group was (326.9%) and (704.7) in NC and VC mice group respectively. (5) The % change in VCAM-1 expression in vaccinated animals relative to naive animals was (67,700) and (91,175) in NC and VC mice groups respectively.