clustering technique is one of the most important techniques of data mining and is the branch of multivariate statistical analysis and a method for grouping similar data in to same clusters. with the databases getting bigger, the researchers try to find efficient and effective clustering methods so that they can make fast and real decisions. thus, in this paper, we proposed an improved ant syst...

Four pigeons were given simultaneous discrimination training with visual patterns arbitrarily divided into two sets, with the stimuli in one set designated A1, B1, C1, and D1 and those in the other set designated A2, B2, C2, and D2. In sequentially introduced training phases, the pigeons were exposed to a series of reversals to establish AB and then CD equivalences. In subsequent testing sessio...

Repeat proteins are composed of tandem structural modules in which close contacts do not extend beyond adjacent repeats. Despite the local nature of these close contacts, repeat proteins often unfold as a single, highly coupled unit. Previous studies on the Notch ankyrin domain suggest that this lack of equilibrium unfolding intermediates results both from stabilizing interfaces between each re...

When a major technological innovation spreads out in both high-tech and middle/low-tech industries, new clusters appear, develop and grow at the expenses of “older” historical industrial sites. The literature has, under various labels, recognised three main stages of cluster development: an initial stage sparked by an initial exogenous, shock; a second stage driven by Marshall’s (1920) agglomer...

Although biosynthetic gene clusters (BGCs) have been discovered for hundreds of bacterial metabolites, our knowledge of their diversity remains limited. Here, we used a novel algorithm to systematically identify BGCs in the extensive extant microbial sequencing data. Network analysis of the predicted BGCs revealed large gene cluster families, the vast majority uncharacterized. We experimentally...

The radial distribution of globular clusters in our Galaxy, M 31 and M 87 is studied and compared with that of halo stars. The globular cluster distributions seem significantly flatter than those of the parent-galaxy stellar bulge. Assuming this is a consequence of an evolution of the globular cluster distribution in these galaxies, a comparison with the (unevolved) stellar distribution allows ...

Dedicated to Professor G. M. Schwab on his 80. birthday The onset of the Lm edge of the X-ray absorption spectrum of platinum in F-zeolites involves an electronic transition from core to band levels producing a so-called white line. The spectral area of this increases and the edge position shifts to higher energies, first when the platinum particle size becomes small enough so that the clusters...

Within the complex set of activities that comprise the scientific method, three clusters of activities can be recognized: experimentation, mathematization, and conceptual analysis. In psychology, the first two of these clusters are well-known and valued, but the third seems less known and valued. The authors show the value of these three clusters of scientific method activities in the works of ...

Clustering has the following challenges: 1) clusters with arbitrary shapes; 2) minimal domain knowledge to determine the input parameters; 3) scalability for large data sets. Density-based clustering has been recognized as a powerful approach for discovering clusters with arbitrary shapes. However, the other two challenges still remain in most existing clustering algorithms. In this paper, we e...

Forty rhizobia nodulating four Acacia species (A. gummifera, A. raddiana, A. cyanophylla, and A. horrida) were isolated from different sites in Morocco. These rhizobia were compared by analyzing both the 16S rRNA gene (rDNA) and the 16S-23S rRNA spacer by PCR with restriction fragment length polymorphism (RFLP) analysis. Analysis of the length of 16S-23S spacer showed a considerable diversity w...