Empirical Models for Dark Matter Halos. III. The Kormendy relation and the log(rho_e)-log(R_e) relation

We have recently shown that the 3-parameter density-profile model from Prugniel & Simien provides a better fit to simulated, galaxy- and cluster-sized, dark matter halos than an NFW-like model with arbitrary inner profile slope gamma (Paper I). By construction, the parameters of the Prugniel-Simien model equate to those of the Sersic R^{1/n} function fitted to the projected distribution. Using the Prugniel-Simien model, we are therefore able to show that the location of simulated (10^{12} M_sun) galaxy-sized dark matter halos in the _e-log(R_e) diagram coincides with that of brightest cluster galaxies, i.e., the dark matter halos appear consistent with the Kormendy relation defined by luminous elliptical galaxies. These objects are also seen to define the new, and equally strong, relation log(rho_e) = 0.5 - 2.5log(R_e), in which rho_e is the internal density at r=R_e. Simulated (10^{14.5} M_sun) cluster-sized dark matter halos and the gas component of real galaxy clusters follow the relation log(rho_e) = 2.5[1 - log(R_e)]. Given the shapes of the various density profiles, we are able to conclude that while dwarf elliptical galaxies and galaxy clusters can have dark matter halos with effective radii of comparable size to the effective radii of their baryonic component, luminous elliptical galaxies can not. For increasingly large elliptical galaxies, with increasingly large profile shapes `n', to be dark matter dominated at large radii requires dark matter halos with increasingly large effective radii compared to the effective radii of their stellar component.Comment: AJ, in press. (Paper I can be found at astro-ph/0509417

Robustness of quantum Markov chains

If the conditional information of a classical probability distribution of three random variables is zero, then it obeys a Markov chain condition. If the conditional information is close to zero, then it is known that the distance (minimum relative entropy) of the distribution to the nearest Markov chain distribution is precisely the conditional information. We prove here that this simple situation does not obtain for quantum conditional information. We show that for tri-partite quantum states the quantum conditional information is always a lower bound for the minimum relative entropy distance to a quantum Markov chain state, but the distance can be much greater; indeed the two quantities can be of different asymptotic order and may even differ by a dimensional factor.Comment: 14 pages, no figures; not for the feeble-minde

Electronic transport in films of colloidal CdSe nanocrystals

We present results for electronic transport measurements on large three-dimensional arrays of CdSe nanocrystals. In response to a step in the applied voltage, we observe a power-law decay of the current over five orders of magnitude in time. Furthermore, we observe no steady-state dark current for fields up to 10^6 V/cm and times as long as 2x10^4 seconds. Although the power-law form of the decay is quite general, there are quantitative variations with temperature, applied field, sample history, and the material parameters of the array. Despite evidence that the charge injected into the film during the measurement causes the decay of current, we find field-scaling of the current at all times. The observation of extremely long-lived current transients suggests the importance of long-range Coulomb interactions between charges on different nanocrystals.Comment: 11 pages, 10 figure

Monte-Carlo Simulations of the Dynamical Behavior of the Coulomb Glass

We study the dynamical behavior of disordered many-particle systems with long-range Coulomb interactions by means of damage-spreading simulations. In this type of Monte-Carlo simulations one investigates the time evolution of the damage, i.e. the difference of the occupation numbers of two systems, subjected to the same thermal noise. We analyze the dependence of the damage on temperature and disorder strength. For zero disorder the spreading transition coincides with the equilibrium phase transition, whereas for finite disorder, we find evidence for a dynamical phase transition well below the transition temperature of the pure system.Comment: 10 pages RevTeX, 8 Postscript figure

Fluctuations of Matrix Entries of Regular Functions of Wigner Matrices

We study the fluctuations of the matrix entries of regular functions of Wigner random matrices in the limit when the matrix size goes to infinity. In the case of the Gaussian ensembles (GOE and GUE) this problem was considered by A.Lytova and L.Pastur in J. Stat. Phys., v.134, 147-159 (2009). Our results are valid provided the off-diagonal matrix entries have finite fourth moment, the diagonal matrix entries have finite second moment, and the test functions have four continuous derivatives in a neighborhood of the support of the Wigner semicircle law.Comment: minor corrections; the manuscript will appear in the Journal of Statistical Physic

Electrical transport studies of quench condensed Bi films at the initial stage of film growth: Structural transition and the possible formation of electron droplets

The electrical transport properties of amorphous Bi films prepared by sequential quench deposition have been studied in situ. A superconductor-insulator (S-I) transition was observed as the film was made increasingly thicker, consistent with previous studies. Unexpected behavior was found at the initial stage of film growth, a regime not explored in detail prior to the present work. As the temperature was lowered, a positive temperature coefficient of resistance (dR/dT > 0) emerged, with the resistance reaching a minimum before the dR/dT became negative again. This behavior was accompanied by a non-linear and asymmetric I-V characteristic. As the film became thicker, conventional variable-range hopping (VRH) was recovered. We attribute the observed crossover in the electrical transport properties to an amorphous to granular structural transition. The positive dR/dT found in the amorphous phase of Bi formed at the initial stage of film growth was qualitatively explained by the formation of metallic droplets within the electron glass.Comment: 7 pages, 6 figure

The Orphan Adhesion-GPCR GPR126 Is Required for Embryonic Development in the Mouse

Adhesion-GPCRs provide essential cell-cell and cell-matrix interactions in development, and have been implicated in inherited human diseases like Usher Syndrome and bilateral frontoparietal polymicrogyria. They are the second largest subfamily of seven-transmembrane spanning proteins in vertebrates, but the function of most of these receptors is still not understood. The orphan Adhesion-GPCR GPR126 has recently been shown to play an essential role in the myelination of peripheral nerves in zebrafish. In parallel, whole-genome association studies have implicated variation at the GPR126 locus as a determinant of body height in the human population. The physiological function of GPR126 in mammals is still unknown. We describe a targeted mutation of GPR126 in the mouse, and show that GPR126 is required for embryonic viability and cardiovascular development

The European Registry for Patients with Mechanical Circulatory Support (EUROMACS)

OBJECTIVES: A second paediatric report has been generated from the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). The purpose of EUROMACS, which is operated by the European Association for Cardio-Thoracic Surgery, is to gather data related to durable mechanical circulatory support for scientific purposes and to publish reports with respect to the course of mechanical circulatory support therapy. Since the first report issued, efforts to increase compliance and participation have been extended. Additionally, the data provided the opportunity to analyse patients of younger age and lower weight. METHODS: Participating hospitals contributed pre-, peri- and long-term postoperative data on mechanical circulatory support implants to the registry. Data for all implants in paediatric patients (≤19 years of age) performed from 1 January 2000 to 1 July 2019 were analysed. This report includes updates of patient characteristics, implant frequency, outcome (including mortality rates, transplants and recovery rates) as well as adverse events including neurological dysfunction, device malfunction, major infection and bleeding. RESULTS: Twenty-nine hospitals contributed 398 registered implants in 353 patients (150 female, 203 male) to the registry. The most frequent aetiology of heart failure was any form of cardiomyopathy (61%), followed by congenital heart disease and myocarditis (16.4% and 16.1%, respectively). Competing outcomes analysis revealed that a total of 80% survived to transplant or recovery or are ongoing; at the 2-year follow-up examination, 20% died while on support. At 12 months, 46.7% received transplants, 8.7% were weaned from their device and 18.5% died. The 3-month adverse events rate was 1.69 per patient-year for device malfunction including pump exchange, 0.48 for major bleeding, 0.64 for major infection and 0.78 for neurological events. CONCLUSIONS: The overall survival rate was 81.5% at 12 months following ventricular assist device implant. The comparison of survival rates of the early and later eras shows no significant difference. A focus on specific subgroups showed that survival was less in patients of younger age (<1 year of age) (P = 0.01) and lower weight (<20 kg) (P = 0.015). Transplant rates at 6 months contin