Data clustering is one of the most popular techniques of information management, which is used in many applications of science and engineering such as machine learning, pattern reorganization, image processing, data mining, and web mining. Different algorithms have been suggested by researchers, where the evolutionary algorithms are the best in data clustering and especially in big datasets. It...

The objective of this paper is to propose three modified versions of the Gravitational Search Algorithm for continuous optimization problems. Although the Gravitational Search Algorithm is a recently introduced promising memory-less heuristic but its performance is not so satisfactory in multimodal problems particularly during the later iterations. With a view to improve the exploration and exp...

The Gravitational Search Algorithm (GSA) is a novel heuristic optimization method based on the law of gravity and mass interactions. It has been proven that this algorithm has good ability to search for the global optimum, but it suffers from slow searching speed in the last iterations. This work proposes a hybrid of Particle Swarm Optimization (PSO) and GSA to resolve the aforementioned proble...

Glutamate 1-semialdehyde aminotransferase (GSA-AT) is the last enzyme in the C5 pathway converting glutamate into the tetrapyrrole precursor delta-aminolevulinate in plants, algae, and several bacteria. Sequence analysis of the genes encoding GSA-AT in barley, Synechococcus, and Escherichia coli revealed 50-70% similarity in the primary structures of the proteins. The enzyme is inhibited rapidl...

Salicylic acid (SA) is a putative signal that activates plant resistance to pathogens. SA levels increase systemically following the hypersensitive response produced by tobacco mosaic virus (TMV) inoculation of tobacco (Nicotiana tabacum L. cv Xanthi-nc) leaves. The SA increase in the inoculated leaf coincided with the appearance of a [beta]-glucosidase-hydrolyzable SA conjugate identified as [...

50828: EVIDENCE FOR A MAJOR, EARLY PROTEROZO... file:///Users/jbrady/JBB_Documents/JBB/Abstracts/GSA,%201999%20-... 1 of 2 3/5/08 7:39 AM 1999 GSA Annual Meeting -Denver, Colorado

Lateral branches in higher plants are often maintained at specific angles with respect to gravity, a quantity known as the gravitropic setpoint angle (GSA) [1]. Despite the importance of GSA control as a fundamental determinant of plant form, the mechanisms underlying gravity-dependent angled growth are not known. Here we address the central questions of how stable isotropic growth of a branch ...

The stimulatory GTP-binding protein Gsa transmits signals from catecholamine receptors to activate adenylyl cyclase and thereby initiate a cascade leading to cardiac chronotropy and inotropy. Transgenic mice overexpressing the Gs a subunit (Gsa) selectively in their hearts exhibit increased cardiac contractility in response to b-adrenergic receptor stimulation. However, with aging, these mice d...