Evolutionary Dynamics and Optimization: Neutral Networks as Model-Landscapes for RNA Secondary-Structure Folding-Landscapes

We view the folding of RNA-sequences as a map that assigns a pattern of base pairings to each sequence, known as secondary structure. These preimages can be constructed as random graphs (i.e. the neutral networks associated to the structure $s$). By interpreting the secondary structure as biological information we can formulate the so called Error Threshold of Shapes as an extension of Eigen's et al. concept of an error threshold in the single peak landscape. Analogue to the approach of Derrida & Peliti for a of the population on the neutral network. On the one hand this model of a single shape landscape allows the derivation of analytical results, on the other hand the concept gives rise to study various scenarios by means of simulations, e.g. the interaction of two different networks. It turns out that the intersection of two sets of compatible sequences (with respect to the pair of secondary structures) plays a key role in the search for ''fitter'' secondary structures.Comment: 20 pages, uuencoded compressed postscript-file, Proc. of ECAL '95 conference, to appear., email: chris @ imb-jena.d

Structure

An exploration of ground’s connections to structure (joint-carving, naturalness). The notion of structure is often invoked in connection to ground, because grounding is understood to impose constraints on the ‘structure of reality’. There is another, technical sense of structure, sometimes captured with reference to the notion of ‘joint-carving’. Both of these senses of structure as well as their potential connections are discussed

Structure of Sn_1-xGe_x random alloys as obtained from the coherent potential approximation

The structure of the Sn1-xGex random alloys is studied using density functional theory and the coherent potential approximation. We report on the deviation of the Sn1-xGex alloys from Vegard's law, addressing their full compositional range. The findings are compared to the related Si1-xGex alloys and to experimental results. Interestingly, the deviation from Vegard's law is quantitatively and qualitatively different between the Sn1-xGex and Si1-xGex alloys. An almost linear dependence of the bulk modulus as a function of composition is found for Si1-xGex, whereas for Sn1-xGex the dependence is strongly nonlinear

Structure–property relationships of iron arsenide superconductors

Iron based superconductors sent material scientists into a renewed excitement reminiscent of the time when the first high-Tc superconductors were discovered 25 years ago. This feature article reviews relationships between structural chemistry and magnetic as well as superconducting properties of iron arsenide compounds, which are outstandingly rich and uniquely coupled. Particular attention is paid to the nature of the structural phase transitions of the parent compounds and their possible origins, on effects of doping on the crystal structures and on the coexistence of magnetic ordering and superconductivity. In spite of the many fascinating insights that have already enriched the research on superconductivity, many questions are still open and prove iron based superconductors to be a good recipe for future discoveries in this lively field

Effects of Asset Structure, Operating Cash Flow, and Profitability on Debt Policy in Property and Real Estate Companies on the Indonesia Stock Exchange Period 2013-2017

This study aims to determine the effect of asset structure, operating cash flow, and profitability on debt policy in property and real estate companies in the Indonesia Stock Exchange in 2013-2017. The analytical method used is multiple linear regression, F test and t test. The results of the analysis of this study indicate that the structure of assets, operating cash flows, and profitability have a simultaneous effect on debt policy. Meanwhile the analysis partially shows that the asset structure, operating cash flows, and profitability do not partially affect debt policy

Combinatorial Penalties: Which structures are preserved by convex relaxations?

We consider the homogeneous and the non-homogeneous convex relaxations for combinatorial penalty functions defined on support sets. Our study identifies key differences in the tightness of the resulting relaxations through the notion of the lower combinatorial envelope of a set-function along with new necessary conditions for support identification. We then propose a general adaptive estimator for convex monotone regularizers, and derive new sufficient conditions for support recovery in the asymptotic setting

Factors Affecting Capital Structure and Stock Prices of Agricultural and Mining Companies

The purpose of this study was to analyze the influence of business risk, asset growth, sales growth, earning per share, and asset structure to capital structure and share price. This study involved mining and agriculture companies listed on IDX within the period of 2010-2017. The analysis employed eViews 9. Based on the hypothesis testing, it was found that that business risk, sales growth, and asset structure do not have a significant effect on capital structure. However, asset growth has a significant influence. Furthermore, sales growth and EPS do not have a significant effect on share price, but the asset structure has a significant influence. This research is a development of previous research by adding earnings per share as an independent variable and covering the period 2010 - 2017 in order to show the most actual conditions. Company management can make the results of this study a consideration in determining the optimal capital structure.   This study only examined the mining and agricultural sectors on the Indonesian stock exchange