1,302 research outputs found

    Surface tension of the isotropic-nematic interface

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    We present the first calculations of the pressure tensor profile in the vicinity of the planar interface between isotropic liquid and nematic liquid crystal, using Onsager's density functional theory and computer simulation. When the liquid crystal director is aligned parallel to the interface, the situation of lowest free energy, there is a large tension on the nematic side of the interface and a small compressive region on the isotropic side. By contrast, for perpendicular alignment, the tension is on the isotropic side. There is excellent agreement between theory and simulation both in the forms of the pressure tensor profiles, and the values of the surface tension.Comment: Minor changes; to appear in Phys. Rev.

    Maternal and child reflective functioning in the context of child sexual abuse: pathways to depression and externalising difficulties

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    BACKGROUND: Sexual abuse is a well-recognised risk factor for child psychopathology. Little is known regarding whether child and maternal mentalization can be considered a potential resource or protective factor in this context, respectively, mediating or moderating the relationship between sexual abuse and psychopathology. OBJECTIVE: The aims of this study were (1) to explore the relationships between child and maternal mentalizing, measured as reflective functioning (RF), and child depressive symptoms and externalising difficulties; and (2) to examine whether child mentalizing mediates the relationship between child sexual abuse (CSA) and psychopathology. METHOD: A total of 168 children aged 7-12 years and their mothers participated in the study. The sample included 74 dyads where children had experienced sexual abuse. The Child Attachment Interview was rated by using the Child Reflective Functioning Scale to assess children's mentalization, and the Child Depression Inventory was used to assess depressive symptoms. Mothers completed the Parent Development Interview to assess maternal RF and the Child Behavior Checklist to assess their child's externalising difficulties. A model involving direct and indirect paths from CSA, child and maternal RF to child psychopathology was examined using Mplus software. RESULTS: Child mentalization partially mediated the relationships between CSA and depressive symptoms, as well as the relationship between CSA and externalising difficulties. Maternal mentalization was an independent predictor of child externalising difficulties, with higher maternal RF associated with less externalising difficulties. DISCUSSION: The findings indicate that by ages 7-12, child mentalization is an important inner resource associated with lower depression and externalising. In addition, this study provides new evidence of the importance of the parent's mentalizing stance for the development of self-regulation and externalising difficulties in both abused and non-abused children. The clinical implications are discussed

    Extreme Electron-Phonon Coupling in Boron-based Layered Superconductors

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    The phonon-mode decomposition of the electron-phonon coupling in the MgB2-like system Li_{1-x}BC is explored using first principles calculations. It is found that the high temperature superconductivity of such systems results from extremely strong coupling to only ~2% of the phonon modes. Novel characteristics of E_2g branches include (1) ``mode lambda'' values of 25 and greater compared to a mean of 0.4\sim 0.4 for other modes, (2) a precipitous Kohn anomaly, and (3) E_2g phonon linewidths within a factor of ~2 of the frequency itself, indicating impending breakdown of linear electron-phonon theory. This behavior in borne out by recent inelastic x-ray scattering studies of MgB2 by Shukla et al.Comment: 4 two-column pages, 4 figures. Equations simplified. Figure 4 changed. Comparison with new data include

    Transverse instability and its long-term development for solitary waves of the (2+1)-Boussinesq equation

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    The stability properties of line solitary wave solutions of the (2+1)-dimensional Boussinesq equation with respect to transverse perturbations and their consequences are considered. A geometric condition arising from a multi-symplectic formulation of this equation gives an explicit relation between the parameters for transverse instability when the transverse wavenumber is small. The Evans function is then computed explicitly, giving the eigenvalues for transverse instability for all transverse wavenumbers. To determine the nonlinear and long time implications of transverse instability, numerical simulations are performed using pseudospectral discretization. The numerics confirm the analytic results, and in all cases studied, transverse instability leads to collapse.Comment: 16 pages, 8 figures; submitted to Phys. Rev.

    Modeling of Rotational Nonequilibrium in Post-Normal Shock Flow Analyses

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106447/1/AIAA2013-191.pd

    Using the attachment network Q-sort for profiling one's attachment style with different attachment-figures

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    Attachment instruments vary substantially in practicability of administration, employment of categorical versus dimensional scoring, quality of scales, and applicability to different attachment figures. The Attachment Network Q-sort (ANQ) is a self-report, quasi-qualitative instrument that discriminates relationship-specific attachment styles for multiple attachment figures. The current study assesses the properties of the ANQ in psychotherapy patients and in non-patient respondents, using mother, father and romantic partner as possible attachment figures. Analyzing the ANQ-data with latent class analysis, we found four types or classes of participants: a group with an overall secure profile, a group only insecure for father, a group only insecure for mother, and a group insecure for mother as well as father but not for partner (if available). These profiles proved to have good concurrent, discriminant and construct validity. We conclude that the ANQ is potentially a useful alternative clinical self-report instrument to assess combinations of attachment styles for a range of attachment figures such as parents and a romantic partner

    A Model for the Elasticity of Compressed Emulsions

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    We present a new model to describe the unusual elastic properties of compressed emulsions. The response of a single droplet under compression is investigated numerically for different Wigner-Seitz cells. The response is softer than harmonic, and depends on the coordination number of the droplet. Using these results, we propose a new effective inter-droplet potential which is used to determine the elastic response of a monodisperse collection of disordered droplets as a function of volume fraction. Our results are in excellent agreement with recent experiments. This suggests that anharmonicity, together with disorder, are responsible for the quasi-linear increase of GG and Π\Pi observed at φc\varphi_c.Comment: RevTeX with psfig-included figures and a galley macr

    Radiating dipoles in photonic crystals

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    The radiation dynamics of a dipole antenna embedded in a Photonic Crystal are modeled by an initially excited harmonic oscillator coupled to a non--Markovian bath of harmonic oscillators representing the colored electromagnetic vacuum within the crystal. Realistic coupling constants based on the natural modes of the Photonic Crystal, i.e., Bloch waves and their associated dispersion relation, are derived. For simple model systems, well-known results such as decay times and emission spectra are reproduced. This approach enables direct incorporation of realistic band structure computations into studies of radiative emission from atoms and molecules within photonic crystals. We therefore provide a predictive and interpretative tool for experiments in both the microwave and optical regimes.Comment: Phys. Rev. E, accepte

    A guanosine 5′-triphosphate-dependent protein kinase is localized in the outer envelope membrane of pea chloroplasts

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    A guanosine 5-triphosphate (GTP)-dependent protein kinase was detected in preparations of outer chloroplast envelope membranes of pea (Pisum sativum L.) chloroplasts. The protein-kinase activity was capable of phosphorylating several envelope-membrane proteins. The major phosphorylated products were 23- and 32.5-kilo-dalton proteins of the outer envelope membrane. Several other envelope proteins were labeled to a lesser extent. Following acid hydrolysis of the labeled proteins, most of the label was detected as phosphoserine with only minor amounts detected as phosphothreonine. Several criteria were used to distinguish the GTP-dependent protein kinase from an ATP-dependent kinase also present in the outer envelope membrane. The ATP-dependent kinase phosphorylated a very different set of envelope-membrane proteins. Heparin inhibited the GTP-dependent kinase but had little effect upon the ATP-dependent enzyme. The GTP-dependent enzyme accepted phosvitin as an external protein substrate whereas the ATP-dependent enzyme did not. The outer membrane of the chloroplast envelope also contained a phosphotransferase capable of transferring labeled phosphate from [-32P]GTP to ADP to yield (-32P]ATP. Consequently, addition of ADP to a GTP-dependent protein-kinase assay resulted in a switch in the pattern of labeled products from that seen with GTP to that typically seen with ATP

    Novel gonadal characteristics in an aged bovine freemartin

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    The gonads from a five year old freemartin Holstein animal were subjected to morphological analysis and to immunohistochemistry using antibodies against developmental and functional markers. We demonstrate, for the first time, the retention of anti-mullerian hormone (AMH) producing intratubular cells (Sertoli cells) in the context of abundant steroidogenic interstitial cells, and structures consistent with clusters of luteal cells. This novel report describes the clinical, gross and histological findings accompanying this newly described gonadal immunophenotype, and its implication in the understanding of freemartin development
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