Dependence of nucleotide physical properties on their placement in codons and determinative degree

Various physical properties such as dipole moment, heat of formation and energy of the most stable formation of nucleotides and bases were calculated by PM3 (modified neglect of diatomic overlap, parametric method number 3) and AM1 (Austin model 1) methods. As distinct from previous calculations, for nucleotides the interaction with neighbours is taken into account up to gradient of convergence equaling 1. The dependences of these variables from the place in the codon and the determinative degree were obtained. The difference of these variables for codons and anticodons is shown.Comment: 13 pages, 8 figures, PD

Bayesian Synthesis: Combining subjective analyses, with an application to ozone data

Bayesian model averaging enables one to combine the disparate predictions of a number of models in a coherent fashion, leading to superior predictive performance. The improvement in performance arises from averaging models that make different predictions. In this work, we tap into perhaps the biggest driver of different predictions---different analysts---in order to gain the full benefits of model averaging. In a standard implementation of our method, several data analysts work independently on portions of a data set, eliciting separate models which are eventually updated and combined through a specific weighting method. We call this modeling procedure Bayesian Synthesis. The methodology helps to alleviate concerns about the sizable gap between the foundational underpinnings of the Bayesian paradigm and the practice of Bayesian statistics. In experimental work we show that human modeling has predictive performance superior to that of many automatic modeling techniques, including AIC, BIC, Smoothing Splines, CART, Bagged CART, Bayes CART, BMA and LARS, and only slightly inferior to that of BART. We also show that Bayesian Synthesis further improves predictive performance. Additionally, we examine the predictive performance of a simple average across analysts, which we dub Convex Synthesis, and find that it also produces an improvement.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS444 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

An investigation of site-bond percolation on many lattices

A calculation of site-bond percolation thresholds in many lattices in two to five dimensions is presented. The line of threshold values has been parametrized in the literature, but we show here that there are strong deviations from the known approximate equations. We propose an alternative parametrization that lies much closer to the numerical valuesComment: LaTeX, 14 pages, 6 figures, 5 tables, submitted to Int. J. Mod. Phys.

Broadband Quantum Efficiency Enhancement in High Index Nanowires Resonators

Light trapping in sub-wavelength semiconductor nanowires (NWs) offers a promising approach to simultaneously reducing material consumption and enhancing photovoltaic performance. Nevertheless, the absorption efficiency of a NW, defined by the ratio of optical absorption cross section to the NW diameter, lingers around 1 in existing NW photonic devices, and the absorption enhancement suffers from a narrow spectral width. Here, we show that the absorption efficiency can be significantly improved in NWs with higher refractive indices, by an experimental observation of up to 350% external quantum efficiency (EQE) in lead sulfide (PbS) NW resonators, a 3-fold increase compared to Si NWs. Furthermore, broadband absorption enhancement is achieved in single tapered NWs, where light of various wavelengths is absorbed at segments with different diameters analogous to a tandem solar cell. Overall, the single NW Schottky junction solar cells benefit from optical resonance, near bandgap open circuit voltage, and long minority carrier diffusion length, demonstrating power conversion efficiency (PCE) comparable to single Si NW coaxial p-n junction cells11, but with much simpler fabrication processes

Analysis of Service-Retrieved TBC-Coated Industrial Gas Turbine Components

Thermal barrier coatings (TBCs) have been widely used in gas turbine applications such as aerospace and power generation. TBC systems serve numerous purposes – the bond coat acts as a sacrificial layer for oxidation and the ceramic top coat works together with internal cooling systems to protect the superalloys from extreme temperature environments. With the rising demand for better fuel efficiency, the hot gas temperature within modern gas turbine engines has exceeded the working temperature of most advanced superalloys. The state-of-the-art TBCs have raised the high temperature capabilities of modern superalloys to a new level and have become an absolute necessity in modern gas turbine applications. While most research focus on the improvements of TBCs, the present study examines the environmental attacks which could lead to failures of TBCs. To be more exact, sand and dust particles often enter the mainstream hot gas flow path of gas turbines due to the powerful suction of its compressors, and internally generated particles, such as wear debris of the components, also could enter the mainstream hot gas flow path of the gas turbine. Once these particles (external and internal) pass through the combustion stage of the gas turbine engine, some of these particles become molten and adhere onto the surface of TBC-coated turbine components. These sand particles and debris gradually build-up in thickness and cause discoloration on the TBC surface. In some cases, the accumulated deposits could reduce the lifetime of TBCs. In other cases where particles carried by the mainstream hot gas flow path remain in solid state after passing through the hot combustion stage, such solid particles are very likely to impact the TBC coated turbine components, mainly the nozzle guide vanes and turbine blades right after the combustion chamber, damaging the TBCs. Since the gas stream inside the gas turbine engine travels at a high velocity, even micron size particles could build-up high kinetic energies. Upon striking the TBCs, these particles wear down the thickness of the TBCs, reducing its thermal insulation capability. Ex-service roll one (R1) turbine nozzle guide vanes and second stage turbine blades were retrieved from a land-based gas turbine for power generation and an aero-engine for transportation respectively, and the three nozzle guide vanes received were contaminated with surface deposits of various colours, while the turbine blades suffered from erosion and foreign object damage. These turbine components were analyzed using laboratory techniques, primarily by scanning electron microscopy with energy dispersive X-ray analysis and X-ray diffraction. In addition, heat treatment tests are also conducted to study the effect of these environmental attacks on the performance and lifetime of TBCs to determine the response of the deposit to prolonged thermal exposure