the purpose of this descriptive- correlational research was to investigate factors affecting use of information and communication technology (ict) by agricultural extension experts. the statistical population of the study consisted of the agricultural extension experts in the khorasane razavi province out of whom 196 individuals were taken as sample, using cochran formula and proportional strat...

Geological disaster causes loss of lives and damage to man-made and natural stuctures. In this paper, a coupling method with optimal combination weighing law and extension model was established. Based on dynamic impact factors such as forest coverage, annual average rainfall, topography and gemorphogy, geologic structure, and type of rock and soil, the amount of disaster points and human engine...

BACKGROUND Branching morphogenesis remodels epithelial tissues into tubular networks. This process is crucial to many organs, from the insect trachea to the vertebrate vasculature. Although Drosophila tracheal development has been well characterized morphologically and genetically, very little is known about the forces involved during morphogenesis. The repertoire of cell behaviors underlying t...

Correct pathfinding by Drosophila photoreceptor axons requires recruitment of p21-activated kinase (Pak) to the membrane by the SH2-SH3 adaptor Dock. Here, we identify the guanine nucleotide exchange factor (GEF) Trio as another essential component in photoreceptor axon guidance. Regulated exchange activity of one of the two Trio GEF domains is critical for accurate pathfinding. This GEF domain...

The guidance of axons to their targets represents a key stage in the assembly of the nervous system, linking the early inductive interactions that establish neuronal identity to the later steps of synapse formation. Neurons are required to extend axons through a variety of cellular environments, and the task of perceiving, integrating, and responding to the myriad signals present in the immedia...

Carcinoma extension to adjacent organs is an important prognostic factor in papillary thyroid carcinoma (PTC). However, the biological behavior of PTC with carcinoma extension varies according to the degree of extension. In this study, we investigated whether and how subdivision of PTC extension accurately reflects patients' prognosis, using a series of 5508 patients with PTC without distant ...

Netrin-1, secreted by floor plate cells, orients axon extension in relation to the ventral midline of the embryonic spinal cord. Oligodendrocyte precursor (OP) cells are born close to the ventral midline and migrate away from the floor plate. Here we show that OP cells, identified by expression of the platelet-derived growth factor alpha receptor, express the netrin receptors dcc and unc5h1 but...

Developing axons are guided to their targets by molecular cues in their local environment. Some cues are shortrange, deriving from cells along axonal pathways. There is also increasing evidence for longer-range guidance cues, in the form of gradients of diffusible chemoattractant molecules, which originate from restricted populations of target cells. The guidance of developing commissurai axons...

Mathematical modeling and computer simulation are valuable tools in unravelling the complexities underlying the morphological development of neurons. In this chapter, we consider biologically plausible mathematical models of neurite initiation, elongation, and branching. These models attempt to describe the intraand extracellular environments of a developing neuron and determine the limiting fa...

Axon extension and guidance require a coordinated assembly of F-actin and microtubules as well as regulated translation. The molecular basis of how the translation of mRNAs encoding guidance proteins could be closely tied to the pace of cytoskeletal assembly is poorly understood. Previous studies have shown that the F-actin-microtubule crosslinker Short stop (Shot) is required for motor and sen...