Extreme self-organization in networks constructed from gene expression data

We study networks constructed from gene expression data obtained from many types of cancers. The networks are constructed by connecting vertices that belong to each others' list of K-nearest-neighbors, with K being an a priori selected non-negative integer. We introduce an order parameter for characterizing the homogeneity of the networks. On minimizing the order parameter with respect to K, degree distribution of the networks shows power-law behavior in the tails with an exponent of unity. Analysis of the eigenvalue spectrum of the networks confirms the presence of the power-law and small-world behavior. We discuss the significance of these findings in the context of evolutionary biological processes.Comment: 4 pages including 3 eps figures, revtex. Revisions as in published versio

Leveraging Social Capital through Classroom Communities of Practice

Educators have advocated the use of informal complementary learning approaches such as Communities of Practice (CoPs) to support existing formal educational structures. They argue that educational structures need to leverage its social capital through informal learning to support the sociocultural approaches to instructions. The CoP concept has been successfully used in business and other organizational settings. However, its application in the educational setting has not been examined in a systematic and deliberate manner. This extended abstract establishes this primary research question by providing a preliminary literature review and also gives an overview of the planned research methodology

A Comparative adsorption study of copper on various industrial solid wastes

The adsorption behavior of Cu on three solid waste materials—sea nodule residue (SNR), fly ash (FA), and red mud (RM)—was investigated. The effects of various parameters, such as pH of the feed solution, contact time, temperature, adsorbate and adsorbent concentration, and particle size of the adsorbent, were studied for optimization of the process parameters. Adsorption of copper increased with increasing time, temperature, pH, and adsorbate concentration, and decreased with increasing initial copper concentration. The equilibrium data fit well with the Langmuir and Freundlich isotherms in the case of SNR, but not on RM and FA, because there was no appreciable effect of temperature on the metal removal on these two adsorbents. The adsorption of copper on SNR followed first-order kinetics involving the surface complex formation mechanism on the charged surface. Under the optimized conditions the adsorption capacity for copper was found to be 19.65 mg/g of SNR, 1.98 mg/g of FA, and 2.28 mg/g of RM. Thus the adsorption capacity of SNR was found to be more than that of activated carbon, thus making it suitable for the treatment of industrial effluents to reduce the level of copper within the permissible limits for its land disposal (3 mg/L) according to ISI guidelines

Polarization and dispersion properties of elliptical hole golden spiral photonic crystal fiber

An elliptical air-hole golden spiral photonic crystal fiber (EGS-PCF) is analyzed with the full-vectorial finite element method. The air-holes in the EGS-PCF are arranged in a spiral pattern governed by the Golden Ratio, where the design has been inspired by the optimal arrangement of seeds found in nature. The EGS-PCF exhibits extremely high birefringence (∼0.022 at operating wavelength 1550 nm) which is particularly useful for generating a polarization stable supercontinuum (SC). The fiber can also be designed to have a Zero Dispersion Wavelength (ZDW) at a suitable wavelength for only one polarization and large negative dispersion for the other, leading to a single-polarization SC. In addition, the fiber dispersion can be designed to obtain ZDWs at 800 nm and 1064 nm simultaneously, which can facilitate broadband supercontinuum generation (SCG) through multi-wavelength pumping

Characterization of silicon nanowire by use of full-vectorial finite element method.

We have carried out a rigorous H-field-based full-vectorial modal analysis and used it to characterize, more accurately, the abrupt dielectric discontinuity of a high index contrast optical waveguide. The full-vectorial H and E fields and the Poynting vector profiles are described in detail. It has been shown through this work that the mode profile of a circular silicon nanowire is not circular and also contains a strong axial field component. The single-mode operation, vector field profiles, modal hybridness, modal ellipticity, and group velocity dispersion of this silicon nanowire are also presented