Hyperostotic tympanic bone spicules in domestic and wild animal species

Hyperostotic tympanic bone spicules (HTBS), or "mucoperiosteal exostoses" (ME, syn.) are small, globular (>= 1 mm in diameter), mostly stalked and drumstick-like, bony structures, which arise from the inner wall of the tympanic bulla and project into the middle ear cavity. HTBS present as mineral densities inside the tympanic bulla on radiographs or computed tomographic (CT) images. They have previously been referred to as "otoliths" and were thought to represent mineral concretions secondary to otitis media. Recently, it was shown that HTBS actually consist of regularly composed bone tissue, covered by normal middle ear mucosa. So far, HTBS have only extensively been described in dogs, where they occur with a prevalence of up to >45%. A recent study detected ME, most likely representing HTBS, in the tympanic cavities of skeletonised skull bones of African lions. To estimate the occurrence of HTBS in other mammal species, the middle ears of adult animals of 78 different domestic, wild, and zoo species undergoing routine necropsy at the Institute of Veterinary Pathology of the LMU Munich, Germany were examined in the present study. HTBS were found in the tympanic bullae of carnivorous species, such as canids (wolf, fox), and in several large felid species (lion, tiger, leopard, cheetah). In contrast, HTBS were not present in domestic cats (more than to 200 cases), small carnivorous species such as mustelids, nor in any primate, ungulate, ruminant, pig, insectivore, or rodent species. The detectability of HTBS by CT of the tympanic bullae of large felids was demonstrated in an African lion. Histologically, HTBS consisted of mature lamellar bone, covered by periosteum and a partially ciliated, flat epithelium, regularly without any apparent inflammatory alterations. The present study demonstrates that HTBS may frequently occur in large felids and in different canid species. These findings should be taken into account when examining the middle ear, or interpreting bulla radiographs/CT-images of the respective species. However, the factors triggering the development of HTBS remain to be identified

The Nonlinear Cosmological Matter Power Spectrum with Massive Neutrinos I: The Halo Model

Measurements of the linear power spectrum of galaxies have placed tight constraints on neutrino masses. We extend the framework of the halo model of cosmological nonlinear matter clustering to include the effect of massive neutrino infall into cold dark matter (CDM) halos. The magnitude of the effect of neutrino clustering for three degenerate mass neutrinos with m_nu=0.9 eV is of order ~1%, within the potential sensitivity of upcoming weak lensing surveys. In order to use these measurements to further constrain--or eventually detect--neutrino masses, accurate theoretical predictions of the nonlinear power spectrum in the presence of massive neutrinos will be needed, likely only possible through high-resolution multiple particle (neutrino, CDM and baryon) simulations.Comment: v2: matches PRD versio

Quantum Magnetic Properties in Perovskite with Anderson Localized Artificial Spin-1/2

Quantum magnetic properties in a geometrically frustrated lattice of spin-1/2 magnet, such as quantum spin liquid or solid and the associated spin fractionalization, are considered key in developing a new phase of matter. The feasibility of observing the quantum magnetic properties, usually found in geometrically frustrated lattice of spin-1/2 magnet, in a perovskite material with controlled disorder is demonstrated. It is found that the controlled chemical disorder, due to the chemical substitution of Ru ions by Co-ions, in a simple perovskite CaRuO3 creates a random prototype configuration of artificial spin-1/2 that forms dimer pairs between the nearest and further away ions. The localization of the Co impurity in the Ru matrix is analyzed using the Anderson localization formulation. The dimers of artificial spin-1/2, due to the localization of Co impurities, exhibit singlet-to-triplet excitation at low temperature without any ordered spin correlation. The localized gapped excitation evolves into a gapless quasi-continuum as dimer pairs break and create freely fluctuating fractionalized spins at high temperature. Together, these properties hint at a new quantum magnetic state with strong resemblance to the resonance valence bond system.Comment: 8 pages, 6 figure

Young's moduli of carbon materials investigated by various classical molecular dynamics schemes

Classical carbon potentials together with classical molecular dynamics are employed to calculate structures and physical properties of such carbon-based materials where quantum mechanical methods fail either due to the excessive size, irregular structure or long-time dynamics. Examples are given by recently synthesized free-standing carbon nanomembranes (CNM) with molecular thickness and macroscopic lateral size as well as by amorphous carbon. Although such potentials, as for instance implemented in LAMMPS, yield reasonably accurate bond lengths and angles for several carbon materials such as graphene, it is not clear how accurate they are in terms of mechanical properties such as Young's moduli. We performed large-scale classical molecular dynamics investigations of three carbon-based materials using the various potentials implemented in LAMMPS as well as the highly sophisticated EDIP potential of Nigel Marks. We demonstrate how the Young's moduli vary with classical potentials and compare to experimental results. Since classical descriptions of carbon are bound to be approximations it is not astonishing that different realizations yield differing results. One should therefore carefully check for which observables a certain potential is suited. We hope to contribute to such a clarification.Comment: 12 pages, 5 figure

Strategic Networking for Online Success

The growth of online social networks and the decreasing effectiveness of traditional marketing have lead to a large interest in social networks. For an appropriate application of new marketing approaches marketers have to understand the impact of interactions and relationships among network members on their individual outcome and network popularity in order to use online social networks effectively in marketing. In this study we analyze networking behavior of music artists for promoting their music. Our sample consists of a set of 480 music artists who actively operate online social networks for personal success on two independent online social network platforms at the same time. Personal network information on both platforms is tracked monthly over a period of six months. Applying a count data approach we relate well-established egocentric network measures to online success. Our results indicate that online success is determined by the social network structure and networking activities of the music artists rather than by their outside popularity. Most importantly, the drivers of online success are not limited to the size of the of the artist’s personal network. The findings of our study provide several insights into the use of personal online social networks for marketing products and services

The Inflationary Perturbation Spectrum

Motivated by the prospect of testing inflation from precision cosmic microwave background observations, we present analytic results for scalar and tensor perturbations in single-field inflation models based on the application of uniform approximations. This technique is systematically improvable, possesses controlled error bounds, and does not rely on assuming the slow-roll parameters to be constant. We provide closed-form expressions for the power spectra and the corresponding scalar and tensor spectral indices.Comment: 4 pages, 1 figur

Nonparametric Dark Energy Reconstruction from Supernova Data

Understanding the origin of the accelerated expansion of the Universe poses one of the greatest challenges in physics today. Lacking a compelling fundamental theory to test, observational efforts are targeted at a better characterization of the underlying cause. If a new form of mass-energy, dark energy, is driving the acceleration, the redshift evolution of the equation of state parameter w(z) will hold essential clues as to its origin. To best exploit data from observations it is necessary to develop a robust and accurate reconstruction approach, with controlled errors, for w(z). We introduce a new, nonparametric method for solving the associated statistical inverse problem based on Gaussian Process modeling and Markov chain Monte Carlo sampling. Applying this method to recent supernova measurements, we reconstruct the continuous history of w out to redshift z=1.5.Comment: 4 pages, 2 figures, accepted for publication in Physical Review Letter

The Rotationally-Resolved Absorption Spectrum of Formaldehyde from 6547 to 7051 cm−1

We report new experimental data on the rotationally resolved room temperature absorption spectrum of CH2O in the near infrared (NIR) region between 6804 and 7051 cm–1 (1470–1418 nm). Data have been obtained by cavity enhanced absorption spectroscopy and complement the spectrum in the wavelength range 6547–6804 cm–1, obtained using virtually the same experimental set-up and already published in an earlier publication (Staak et al., J. Mol. Spectrosc. 229 (2005) 115–121). Several vibrational combination bands occur in this region and give rise to a congested spectrum and over 4500 lines with cross- sections over 5 · 10–23 cm2 were observed. Recent experimental studies using NIR absorption spectroscopy for quantifying CH2O in different chemical systems indicate that the absorption cross-sections obtained by Staak et al. may have been overestimated. The results of these experiments are reviewed here and a recommendation for absolute absorption cross sections of CH2O in the NIR range will be given. Absolute absorption cross-sections stated here are corrected by the recommended factor

Far-infrared spectra of lateral quantum dot molecules

We study effects of electron-electron interactions and confinement potential on the magneto-optical absorption spectrum in the far-infrared range of lateral quantum dot molecules. We calculate far-infrared (FIR) spectra for three different quantum dot molecule confinement potentials. We use accurate exact diagonalization technique for two interacting electrons and calculate dipole-transitions between two-body levels with perturbation theory. We conclude that the two-electron FIR spectra directly reflect the symmetry of the confinement potential and interactions cause only small shifts in the spectra. These predictions could be tested in experiments with nonparabolic quantum dots by changing the number of confined electrons. We also calculate FIR spectra for up to six noninteracting electrons and observe some additional features in the spectrum.Comment: For better quality Figs download manuscript from http://www.fyslab.hut.fi/~mma/FIR/Helle_qdmfir.ps.g

Three-Dimensionally Confined Optical Modes in Quantum Well Microtube Ring Resonators

We report on microtube ring resonators with quantum wells embedded as an optically active material. Optical modes are observed over a broad energy range. Their properties strongly depend on the exact geometry of the microtube along its axis. In particular we observe (i) preferential emission of light on the inside edge of the microtube and (ii) confinement of light also in direction of the tube axis by an axially varying geometry which is explained in an expanded waveguide model.Comment: 5 pages, 4 figure