Characterisation of FAD-family folds using a machine learning approach

Flavin adenine dinucleotide (FAD) and its derivatives play a crucial role in biological processes. They are major organic cofactors and electron carriers in both enzymatic activities and biochemical pathways. We have analysed the relationships between sequence and structure of FAD-containing proteins using a machine learning approach. Decision trees were generated using the C4.5 algorithm as a means of automatically generating rules from biological databases (TOPS, CATH and PDB). These rules were then used as background knowledge for an ILP system to characterise the four different classes of FAD-family folds classified in Dym and Eisenberg (2001). These FAD-family folds are: glutathione reductase (GR), ferredoxin reductase (FR), p-cresol methylhydroxylase (PCMH) and pyruvate oxidase (PO). Each FADfamily was characterised by a set of rules. The “knowledge patterns” generated from this approach are a set of rules containing conserved sequence motifs, secondary structure sequence elements and folding information. Every rule was then verified using statistical evaluation on the measured significance of each rule. We show that this machine learning approach is capable of learning and discovering interesting patterns from large biological databases and can generate “knowledge patterns” that characterise the FADcontaining proteins, and at the same time classify these proteins into four different families

Magnetism and superconductivity in strongly correlated CeRhIn5

Specific heat studies of CeRhIn5 as functions of pressure and magnetic field have been used to explore the relationship between magnetism and unconventional superconductivity, both of which involve the 4f electron of Ce. Results of these studies cannot be understood as a simple competition for Fermi-surface states and require a new conceptual framework.Comment: 9 pages, 7 figure

Pressure effects on the superconducting thin film Ba1−x_{1-x}Kx_{x}Fe2_{2}As2_{2}

We report electrical resistivity measurements on a high-quality Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ thin film ($x=0.4$) under pressure. The superconducting transition temperature (=39.95 K) of the optimally-doped thin film shows a dome shape with pressure, reaching a maximal value 40.8 K at 11.8 kbar. The unusually high superconducting transition temperature and its anomalous pressure dependence are ascribed to a lattice mismatch between the LaAlO$_3$ substrate and the thin film. The local temperature exponent of the resistivity ($n=d\text{ln}\Delta\rho/d\text{ln}T$) shows a funnel shape around the optimal pressure, suggesting that fluctuations associated with the anomalous normal state are responsible for high-temperature superconductivity.Comment: To appear in Appl. Phys. Let

Imatges i paraules

La idea que vivim en l'era de les imatges és posada en qüestió en aquest escrit, en què es planteja una continuïtat entre etapes molt antigues del desenvolupament humà, on ja existia una harmonia entre la dimensió visual i la sonora o lingüística. L'increment de les imatges, a més, no sembla que posi en perill la capacitat humana, essencial i distintiva, d'adquisició i ús de les llengües. Si de cas, l'allau de les imatges deixarà empremtes en el lèxic; però no influiran en els nivells pregons de les llengües, sotmesos, és clar, al canvi lingüístic ordinari.This article casts doubt over the idea that we live in an era of images, and puts forward a continuity between the far-distant periods of human development, where there was harmony between the visual dimension and that of the sonorous or linguistic ambit. Furthermore, the increase in images does not appear to have threatened the essential and distinctive human capacity for the acquisition and use of languages. It may well be that the veritable avalanche of images will leave its mark on the lexis; but this will not influence the deepest levels of language, which are submitted, naturally, to ordinary linguistic change

Diferència sexual i variació lingüística

This paper presents typical female and male oral traits after surveying the main studies on the topic. The approach used to study linguistic diversity as determined by sex differences is from an anthropological and sociolingüístic view. Sex differences are conditioned by historical and cultural forces that determine the meaning of "being a man" or "being a woman" in a given society. Some of the characteristics of typical communicative behavior in men and women as well as some current indications of change are also examined

Anomalous Pressure Dependence of Kadowaki-Woods ratio and Crystal Field Effects in Mixed-valence YbInCu4

The mixed-valence (MV) compound YbInCu4 was investigated by electrical resistivity and ac specific heat at low temperatures and high pressures. At atmospheric pressure, its Kadowaki-Woods (KW) ratio, A/\gamma ^2, is 16 times smaller than the universal value R_{KW}(=1.0 x 10^-5 \mu \Omega cm mol^2 K^2 mJ^-2), but sharply increases to 16.5R_{KW} at 27 kbar. The pressure-induced change in the KW ratio and deviation from R_{KW} are analyzed in terms of the change in f-orbital degeneracy N and carrier density n. This analysis is further supported by a dramatic change in residual resistivity \rho_0 near 25 kbar, where \rho_0 jumps by a factor of 7.Comment: 4pages, 3figure