1,260 research outputs found

    Molecular Realism in Default Models for Information Theories of Hydrophobic Effects

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    This letter considers several physical arguments about contributions to hydrophobic hydration of inert gases, constructs default models to test them within information theories, and gives information theory predictions using those default models with moment information drawn from simulation of liquid water. Tested physical features include: packing or steric effects, the role of attractive forces that lower the solvent pressure, and the roughly tetrahedral coordination of water molecules in liquid water. Packing effects (hard sphere default model) and packing effects plus attractive forces (Lennard-Jones default model) are ineffective in improving the prediction of hydrophobic hydration free energies of inert gases over the previously used Gibbs and flat default models. However, a conceptually simple cluster Poisson model that incorporates tetrahedral coordination structure in the default model is one of the better performers for these predictions. These results provide a partial rationalization of the remarkable performance of the flat default model with two moments in previous applications. The cluster Poisson default model thus will be the subject of further refinement.Comment: 5 pages including 3 figure

    Paa station i Vestindien for 100 aar siden. Uddrag af breve fra H. G. F. Garde

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    Foliar Application of Several Nitrogen Sources as Fertilisers to Tempranillo Grapevines: Effect on Wine Volatile Composition

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    Foliar nitrogen applications to the vineyard make it possible to improve grape and wine phenolic and amino acid concentration. However, to our knowledge, there is little information about their impacts on the volatile composition of wine. Therefore, the aim of this work was to evaluate the effects of the application of several nitrogen sources in Tempranillo vineyards on wine volatile composition during the first season. Subsequently, two dosages of phenylalanine and urea were applied to the vineyard with the aim of evaluating their effect on wine volatile composition. The results show that the different nitrogen sources applied to the grapevines during the first season did not affect higher alcohols, fatty acids, esters and other volatile compounds in the wines. The two dosages of phenylalanine and urea applied to the vineyard during the second vintage barely affected wine volatile composition. Consequently, this study shows that foliar nitrogen treatments in vineyards did not modify the wine aromatic profile

    Universal trend of the information entropy of a fermion in a mean field

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    We calculate the information entropy of single-particle states in position-space SrS_{r} and momentum-space SkS_{k} for a nucleon in a nucleus, a Λ\Lambda particle in a hypernucleus and an electron in an atomic cluster. It is seen that SrS_{r} and SkS_{k} obey the same approximate functional form as functions of the number of particles, SrS_{r} ({\rm or} Sk)=a+bN1/3S_{k}) = a+bN^{1/3} in all of the above many-body systems in position- and momentum- space separately. The net information content Sr+SkS_{r}+S_{k} is a slowly varying function of NN of the same form as above. The entropy sum Sr+SkS_{r}+S_{k} is invariant to uniform scaling of coordinates and a characteristic of the single-particle states of a specific system. The order of single-particle states according to Sr+SkS_r +S_k is the same as their classification according to energy keeping the quantum number nn constant. The spin-orbit splitting is reproduced correctly. It is also seen that Sr+SkS_{r}+S_{k} enhances with excitation of a fermion in a quantum-mechanical system. Finally, we establish a relationship of Sr+SkS_r +S_k with the energy of the corresponding single-particle state i.e. Sr+Sk=kln(μE+ν)S_r +S_k = k \ln (\mu E +\nu). This relation holds for all the systems under consideration.Comment: 9 pages, latex, 6 figure

    Transcriptome Metabolic Characterization of Tuber borchii SP1—A New Spanish Strain for In Vitro Studies of the Bianchetto Truffle

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    Truffles are ascomycete hypogeous fungi belonging to the Tuberaceae family of the Pezizales order that grow in ectomycorrhizal symbiosis with tree roots, and they are known for their peculiar aromas and flavors. The axenic culture of truffle mycelium is problematic because it is not possible in many cases, and the growth rate is meager when it is possible. This limitation has prompted searching and characterizing new strains that can be handled in laboratory conditions for basic and applied studies. In this work, a new strain of Tuber borchii (strain SP1) was isolated and cultured, and its transcriptome was analyzed under different in vitro culture conditions. The results showed that the highest growth of T. borchii SP1 was obtained using maltose-enriched cultures made with soft-agar and in static submerged cultures made at 22 °C. We analyzed the transcriptome of this strain cultured in different media to establish a framework for future comparative studies, paying particular attention to the central metabolic pathways, principal secondary metabolite gene clusters, and the genes involved in producing volatile aromatic compounds (VOCs). The results showed a transcription signal for around 80% of the annotated genes. In contrast, most of the transcription effort was concentrated on a limited number of genes (20% of genes account for 80% of the transcription), and the transcription profile of the central metabolism genes was similar in the different conditions analyzed. The gene expression profile suggests that T. borchii uses fermentative rather than respiratory metabolism in these cultures, even in aerobic conditions. Finally, there was a reduced expression of genes belonging to secondary metabolite clusters, whereas there was a significative transcription of those involved in producing volatile aromatic compounds
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