A PSO based transportation network design optimization of the mega city Dhaka

Transportation network is a key issue for urban areas and is require to update to fulfill the growing demand modifying existing road(s) and/or constructing new road(s) considering various constraints. In general, transportation network design problem (TNDP) concerns optimal selection of several projects from various alternative proposed projects (with estimated costs) maintaining associated constraints to ensure benefit versus cost. Various approaches have been investigated to solve TNDP in last several decades. Recently, particle swarm optimization (PSO) based method is shown to outperform other methods. However, the most of the existing methods, including PSO, tested on the small scale TNDP. Therefore, the aim of this study is to identify the effectiveness of the PSO based method for a mega city heaving large number nodes and arcs. The mega city considered in this study is Dhaka, the capital of Bangladesh. The experiment has been conducted on the roughly estimated data for exiting network as well as proposed projects. Experimental results for revealed that the method able to select projects for optimal (or near optimal) utilization of a given budget amount. The selected projects are seem to be effective to increase traffic flow while observe on the schematic diagram of the road network

Structural model of the circadian clock KaiB–KaiC complex and mechanism for modulation of KaiC phosphorylation

The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by the KaiA, KaiB and KaiC proteins in the presence of ATP. The principal clock component, KaiC, undergoes regular cycles between hyper- and hypo-phosphorylated states with a period of ca. 24 h that is temperature compensated. KaiA enhances KaiC phosphorylation and this enhancement is antagonized by KaiB. Throughout the cycle Kai proteins interact in a dynamic manner to form complexes of different composition. We present a three-dimensional model of the S. elongatus KaiB–KaiC complex based on X-ray crystallography, negative-stain and cryo-electron microscopy, native gel electrophoresis and modelling techniques. We provide experimental evidence that KaiB dimers interact with KaiC from the same side as KaiA and for a conformational rearrangement of the C-terminal regions of KaiC subunits. The enlarged central channel and thus KaiC subunit separation in the C-terminal ring of the hexamer is consistent with KaiC subunit exchange during the dephosphorylation phase. The proposed binding mode of KaiB explains the observation of simultaneous binding of KaiA and KaiB to KaiC, and provides insight into the mechanism of KaiB's antagonism of KaiA