567 research outputs found

    Thermoelectric and Seebeck coefficients of granular metals

    Full text link
    In this work we present a detailed study and derivation of the thermopower and thermoelectric coefficient of nano-granular metals at large tunneling conductance between the grains, g_T>> 1. An important criterion for the performance of a thermoelectric device is the thermodynamic figure of merit which is derived using the kinetic coefficients of granular metals. All results are valid at intermediate temperatures, E_c>>T/g_T>\delta, where \delta is the mean energy level spacing for a single grain and E_c its charging energy. We show that the electron-electron interaction leads to an increase of the thermopower with decreasing grain size and discuss our results in the light of future generation thermoelectric materials for low temperature applications. The behavior of the figure of merit depending on system parameters like grain size, tunneling conductance, and temperature is presented.Comment: 27 pages, 10 figures, revtex

    Patients' experiences of clinicians' crying during psychotherapy for eating disorders

    Get PDF
    Many psychotherapists have cried in a therapy session. Those clinicians who do cry see it as likely to have a positive impact on the therapy or to have no impact, and therapist personality characteristics have not shown reliable associations to crying in therapy. However, it is not known how patients experience therapists' crying, or whether the patient's view of the therapist's characteristics is related to that experience. This study used an online survey, recruiting 202 patients with eating disorders, 188 of whom had received therapy for an eating disorder, and 105 of whom had experienced a therapist crying. Retrospective data from those 105 individuals indicated that therapists' crying tended to be seen positively, by patients but that perception was influenced by the patients' perceptions of the demeanor of their therapist and their understanding of the meaning of the crying. Although they need to be extended to other disorders, these findings suggest that therapists' crying needs to be understood in the context of the therapist's perceived characteristics and demeanor, rather than being assumed to be positive or to have no impact on the therapy

    Diffusion and Transport Coefficients in Synthetic Opals

    Full text link
    Opals are structures composed of the closed packing of spheres in the size range of nano-to-micro meter. They are sintered to create small necks at the points of contact. We have solved the diffusion problem in such structures. The relation between the diffusion coefficient and the termal and electrical conductivity makes possible to estimate the transport coefficients of opal structures. We estimate this changes as function of the neck size and the mean-free path of the carriers. The theory presented is also applicable to the diffusion problem in other periodic structures.Comment: Submitted to PR

    Solvent contribution to the stability of a physical gel characterized by quasi-elastic neutron scattering

    Full text link
    The dynamics of a physical gel, namely the Low Molecular Mass Organic Gelator {\textit Methyl-4,6-O-benzylidene-α\alpha -D-mannopyranoside (α\alpha-manno)} in water and toluene are probed by neutron scattering. Using high gelator concentrations, we were able to determine, on a timescale from a few ps to 1 ns, the number of solvent molecules that are immobilised by the rigid network formed by the gelators. We found that only few toluene molecules per gelator participate to the network which is formed by hydrogen bonding between the gelators' sugar moieties. In water, however, the interactions leading to the gel formations are weaker, involving dipolar, hydrophobic or ππ\pi-\pi interactions and hydrogen bonds are formed between the gelators and the surrounding water. Therefore, around 10 to 14 water molecules per gelator are immobilised by the presence of the network. This study shows that neutron scattering can give valuable information about the behaviour of solvent confined in a molecular gel.Comment: Langmuir (2015

    Phylogenetically Driven Sequencing of Extremely Halophilic Archaea Reveals Strategies for Static and Dynamic Osmo-response

    Full text link
    © 2014. Organisms across the tree of life use a variety of mechanisms to respond to stress-inducing fluctuations in osmotic conditions. Cellular response mechanisms and phenotypes associated with osmoadaptation also play important roles in bacterial virulence, human health, agricultural production and many other biological systems. To improve understanding of osmoadaptive strategies, we have generated 59 high-quality draft genomes for the haloarchaea (a euryarchaeal clade whose members thrive in hypersaline environments and routinely experience drastic changes in environmental salinity) and analyzed these new genomes in combination with those from 21 previously sequenced haloarchaeal isolates. We propose a generalized model for haloarchaeal management of cytoplasmic osmolarity in response to osmotic shifts, where potassium accumulation and sodium expulsion during osmotic upshock are accomplished via secondary transport using the proton gradient as an energy source, and potassium loss during downshock is via a combination of secondary transport and non-specific ion loss through mechanosensitive channels. We also propose new mechanisms for magnesium and chloride accumulation. We describe the expansion and differentiation of haloarchaeal general transcription factor families, including two novel expansions of the TATA-binding protein family, and discuss their potential for enabling rapid adaptation to environmental fluxes. We challenge a recent high-profile proposal regarding the evolutionary origins of the haloarchaea by showing that inclusion of additional genomes significantly reduces support for a proposed large-scale horizontal gene transfer into the ancestral haloarchaeon from the bacterial domain. The combination of broad (17 genera) and deep (≥5 species in four genera) sampling of a phenotypically unified clade has enabled us to uncover both highly conserved and specialized features of osmoadaptation. Finally, we demonstrate the broad utility of such datasets, for metagenomics, improvements to automated gene annotation and investigations of evolutionary processes

    Anomalous asymmetry of magnetoresistance in NbSe3_3 single crystals

    Full text link
    A pronounced asymmetry of magnetoresistance with respect to the magnetic field direction is observed for NbSe3_3 crystals placed in a magnetic field perpendicular to their conducting planes. It is shown that the effect persists in a wide temperature range and manifests itself starting from a certain magnetic induction value B0B_0, which at T=4.2T=4.2 K corresponds to the transition to the quantum limit, i.to the state where the Landay level splitting exceeds the temperature.Comment: 4 pages, 6 figures, to be appeared in JETP Let

    101 Dothideomycetes genomes: A test case for predicting lifestyles and emergence of pathogens.

    Get PDF
    Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species

    Pregnant women with bronchial asthma benefit from progressive muscle relaxation: A randomized, prospective, controlled trial

    Get PDF
    Background: Asthma is a serious medical problem in pregnancy and is often associated with stress, anger and poor quality of life. The aim of this study was to determine the efficacy of progressive muscle relaxation (PMR) on change in blood pressure, lung parameters, heart rate, anger and health-related quality of life in pregnant women with bronchial asthma. Methods: We treated a sample of 64 pregnant women with bronchial asthma from the local population in an 8-week randomized, prospective, controlled trial. Thirty-two were selected for PMR, and 32 received a placebo intervention. The systolic blood pressure, forced expiratory volume in the first second, peak expiratory flow and heart rate were tested, and the State-Trait Anger Expression Inventory and Health Survey (SF-36) were employed. Results: According to the intend-to-treat principle, a significant reduction in systolic blood pressure and a significant increase in both forced expiratory volume in the first second and peak expiratory flow were observed after PMR. The heart rate showed a significant increase in the coefficient of variation, root mean square of successive differences and high frequency ranges, in addition to a significant reduction in low and middle frequency ranges. A significant reduction on three of five State-Trait Anger Expression Inventory scales, and a significant increase on seven of eight SF-36 scales were observed. Conclusions: PMR appears to be an effective method to improve blood pressure, lung parameters and heart rate, and to decrease anger levels, thus enhancing health-related quality of life in pregnant women with bronchial asthma. Copyright (c) 2006 S. Karger AG, Basel
    corecore