3,260 research outputs found

    A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151

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    The active galaxy NGC 4151 has a crucial role as one of only two active galactic nuclei for which black hole mass measurements based on emission line reverberation mapping can be calibrated against other dynamical methods. Unfortunately, effective calibration requires an accurate distance to NGC 4151, which is currently not available. Recently reported distances range from 4 to 29 megaparsecs (Mpc). Strong peculiar motions make a redshift-based distance very uncertain, and the geometry of the galaxy and its nucleus prohibit accurate measurements using other techniques. Here we report a dust-parallax distance to NGC 4151 of DA=19.0−2.6+2.4D_A = 19.0^{+2.4}_{-2.6} Mpc. The measurement is based on an adaptation of a geometric method proposed previously using the emission line regions of active galaxies. Since this region is too small for current imaging capabilities, we use instead the ratio of the physical-to-angular sizes of the more extended hot dust emission as determined from time-delays and infrared interferometry. This new distance leads to an approximately 1.4-fold increase in the dynamical black hole mass, implying a corresponding correction to emission line reverberation masses of black holes if they are calibrated against the two objects with additional dynamical masses.Comment: Authors' version of a letter published in Nature (27 November 2014); 8 pages, 5 figures, 1 tabl

    Competition between phonon superconductivity and Kondo screening in mixed valence and heavy fermion compounds

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    We consider competition of Kondo effect and s-wave superconductivity in heavy fermion and mixed valence superconductors, using the phenomenological approach for the periodic Anderson model. Similar to the well known results for single-impurity Kondo effect in superconductors, we have found principal possibility of a re-entrant regime of the superconducting transition temperature, TcT_c, in heavy fermion superconductors in a narrow range of model parameters and concentration of f-electrons. Suppression of TcT_c in mixed valence superconductors is much weaker. Our theory has most validity in the low-temperature Fermi liquid regime, without re-entrant behavior of TcT_c. To check its applicability, we performed the fit for the xx-dependence of TcT_c in Ce1−x_{1-x}Lax_xRu3_3Si2_2 and obtained an excellent agreement with the experimental data, although no re-entrance was found in this case. Other experimental data are discussed in the light of our theoretical analysis. In particular, we compare temperatures of the superconducting transition for some known homologs, i.e., the analog periodic lattice compounds with and without f-elements. For a few pairs of homologs superconductivity exists only in the heavy fermion materials, thus confirming uniqueness of superconductivity mechanisms for the latter. We suggest that for some other compounds the value of TcT_c may remain of the same order in the two homologs, if superconductivity originates mainly on some light Fermi surface, but induces sizable superconducting gap on another Fermi surface,for which hybridization or other heavy fermion effects are more significant.Comment: 11 pages, 4 figures, pd

    The Bipolar Prodrome Symptom Interview and Scale-Prospective (BPSS-P): description and validation in a psychiatric sample and healthy controls

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    Objective: The aim of the present study was to investigate the psychometric properties of the Bipolar Prodrome Symptom Interview and Scale-Prospective (BPSS-P), the first specific interview for emerging bipolar disorder (BD) symptoms. Methods: A total of 205 youth aged 12-23 years and/or their caregivers underwent BPSS-P interviews: 129 patients with mood spectrum disorders [ depression spectrum disorder (n = 77), mood disorder not otherwise specified (NOS) (n = 27), BD-NOS (n = 14), bipolar I disorder (BD-I)/bipolar II disorder (BD-II)/cyclothymia (n = 11), 34 with non-mood spectrum disorders, and 42 healthy controls (HCs)]. We used Cronbach\u27s alpha to assess internal consistency; intra-class correlation (ICC) for inter-rater reliability; Spearman\u27s rho for convergent validity with the Young Mania Rating Scale (YMRS), General Behavior Inventory-10-item Mania Form (GBI-M-10), and Cyclothymic-Hypersensitive Temperament (CHT) scale; and analysis of variance for discriminatory power between diagnostic groups. Results: Internal consistency was good to very good for the BPSS-P Mania (Cronbach\u27s alpha = 0.87), Depression (Cronbach\u27s alpha = 0.89), and General Symptom indices (Cronbach\u27s alpha = 0.74). Inter-rater reliability was high for the BPSS-P Total score (ICC = 0.939), and BPSS-P Mania (ICC = 0.934), Depression (ICC = 0.985), and General (ICC = 0.981) indices. Convergent validity was large (rho \u3e= 0.50) between the BPSS-P Mania Index and YMRS, GBI-M-10, and CHT; BPSS-P Depression Index and Montgomery-Asberg Depression Rating Scale (MADRS) and CHT; and BPSS-P General Index and GBI-M-10 and CHT. Expectedly, convergent validity was small (rho = 0.10 to \u3c 0.30) between the BPSS-P Mania Index and MADRS, and BPSS-P Depression Index and YMRS. Furthermore, the BPSS-P and its subscales discriminated each patient group from HCs and from non-mood spectrum patients (except for the BPSS-P General Index). Moreover, the BPSS-P Total score discriminated BD-I/BD-II/cyclothymia from depression spectrum patients, and the BPSS-Mania Index differentiated all three bipolar spectrum groups from depression spectrum patients. Conclusions: The BPSS-P has good to excellent psychometric properties. Its use across multiple settings and predictive validity requires further investigation

    High field x-ray diffraction study on a magnetic-field-induced valence transition in YbInCu4

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    We report the first high-field x-ray diffraction experiment using synchrotron x-rays and pulsed magnetic fields exceeding 30 T. Lattice deformation due to a magnetic-field-induced valence transition in YbInCu4 is studied. It has been found that the Bragg reflection profile at 32 K changes significantly at around 27 T due to the structural transition. In the vicinity of the transition field the low-field and the high-field phases are observed simultaneously as the two distinct Bragg reflection peaks: This is a direct evidence of the fact that the field-induced valence state transition is the first order phase transition. The field-dependence of the low-field-phase Bragg peak intensity is found to be scaled with the magnetization.Comment: 5 pages, 6 figures, submitted to J. Phys. Soc. Jp

    A Simple Separable Exact C*-Algebra not Anti-isomorphic to Itself

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    We give an example of an exact, stably finite, simple. separable C*-algebra D which is not isomorphic to its opposite algebra. Moreover, D has the following additional properties. It is stably finite, approximately divisible, has real rank zero and stable rank one, has a unique tracial state, and the order on projections over D is determined by traces. It also absorbs the Jiang-Su algebra Z, and in fact absorbs the 3^{\infty} UHF algebra. We can also explicitly compute the K-theory of D, namely K_0 (D) = Z[1/3] with the standard order, and K_1 (D) = 0, as well as the Cuntz semigroup of D.Comment: 16 pages; AMSLaTeX. The material on other possible K-groups for such an algebra has been moved to a separate paper (1309.4142 [math.OA]

    Perturbations of nuclear C*-algebras

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    Kadison and Kastler introduced a natural metric on the collection of all C*-subalgebras of the bounded operators on a separable Hilbert space. They conjectured that sufficiently close algebras are unitarily conjugate. We establish this conjecture when one algebra is separable and nuclear. We also consider one-sided versions of these notions, and we obtain embeddings from certain near inclusions involving separable nuclear C*-algebras. At the end of the paper we demonstrate how our methods lead to improved characterisations of some of the types of algebras that are of current interest in the classification programme.Comment: 45 page

    Highly anisotropic Bose-Einstein condensates: crossover to lower dimensionality

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    We develop a simple analytical model based on a variational method to explain the properties of trapped cylindrically symmetric Bose-Einstein condensates (BEC) of varying degrees of anisotropy well into regimes of effective one dimension (1D) and effective two dimension (2D). Our results are accurate in regimes where the Thomas-Fermi approximation breaks down and they are shown to be in agreement with recent experimental data.Comment: 4 pages, 2 figures; significantly more new material added; title and author-list changed due to changes in conten

    Unusual trivial trauma may end with extrusion of a well-functioning penile prosthesis: a case report

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    <p>Abstract</p> <p>Background</p> <p>Diabetes mellitus (DM) is the most common indication for insertion of a penile prosthesis and is a risk factor for infection of such prostheses.</p> <p>Case presentation</p> <p>Two patients presented with infected prostheses following unusual trivial penile trauma. Both patients underwent exploration and removal of the prostheses with uneventful recovery.</p> <p>Conclusion</p> <p>Appropriate sizing of the prosthesis should be taken into account to ensure good concealment and avoid easy exposure of the penis to unexpected trauma. Use of the newly designed antibiotic-coated prostheses appears preferable. As soon as signs of prosthesis infection appeared, extrusion of the device should be expedited.</p
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