Radiographic measurements of the trachea in domestic short haired and Persian cats

Tracheal diameter can be assessed from a thoracic radiograph, with assessment of tracheal diameter in dogs based on ratios between tracheal diameter and a skeletal measurement – however reference ranges are not available for the cat. Tracheal narrowing may cause significant clinical problems, although tracheal hypoplasia in dogs may be clinically silent, and is rarely reported in cats (both mesati- and brachycephalic). The tracheal diameter and trachea:thoracic inlet and trachea:rib ratios were calculated for populations of Domestic Short Haired (DSH) (n=68) and Persian (n=40) cats. This gave reference ranges for radiographic tracheal measurements in these breeds. It is proposed that the tracheal diameter in a normal DSH cat should be 18% of the diameter of the thoracic inlet, and compared to 20% in Persian cats

Dynamical segregation of galaxies in groups and clusters

We have performed a systematic analysis of the dynamics of different galaxy populations in galaxy groups from the 2dFGRS. For this purpose we have combined all the groups into a single system, where velocities v and radius r are expressed adimensionally. We have used several methods to compare the distributions of relative velocities of galaxies with respect to the group centre for samples selected according to their spectral type (as defined by Madgwick et al., 2002), bj band luminosity and B-R colour index. We have found strong segregation effects: spectral type I objects show a statistically narrower velocity distribution than that of galaxies with a substantial star formation activity (type II-IV). Similarly, the same behavior is observed for galaxies with colour index B-R>1 compared to galaxies with B-R<1. Bright (Mb-19) galaxies show the same segregation. It is not important once the sample is restricted to a given spectral type. These effects are particularly important in the central region (Rp<Rvirial/2) and do not have a strong dependence on the mass of the parent group. These trends show a strong correlation between the dynamics of galaxies in groups and star formation rate reflected both by spectral type and by colour index.Comment: 7 pages, 8 figures. Accepted for publication in MNRA

Condensation of `composite bosons' in a rotating BEC

We provide evidence for several novel phases in the dilute limit of rotating BECs. By exact calculation of wavefunctions and energies for small numbers of particles, we show that the states near integer angular momentum per particle are best considered condensates of composite entities, involving vortices and atoms. We are led to this result by explicit comparison with a description purely in terms of vortices. Several parallels with the fractional quantum Hall effect emerge, including the presence of the Pfaffian state.Comment: 4 pages, Latex, 3 figure

The Ca2+ sensor protein Swiprosin-1/EFhd2 is present in neurites and involved in kinesin-mediated transport in neurons

This work was supported by grants from the German Science Foundation (Deutsche Forschungsgemeinschaft, DFG; FOR832, to DM), the German Federal Ministry of Education and Research (01GQ113; to BW), the Bavarian Ministry of Sciences, Research and the Arts in the framework of the Bavarian Molecular Biosystems Reseach Network, the Interdisciplinary Center for Clinical Research (IZKF, Universitatsklinikum Erlangen; E8, to DM; NIII, to BW; Lab rotation to MR), the ELAN Fonds (Universitatsklinikum Erlangen; 11.08.19.1, to IP), and the Alzheimer’s Research UK (EB, FGM).Swiprosin-1/EFhd2 (EFhd2) is a cytoskeletal Ca2+ sensor protein strongly expressed in the brain. It has been shown to interact with mutant tau, which can promote neurodegeneration, but nothing is known about the physiological function of EFhd2 in the nervous system. To elucidate this question, we analyzed EFhd2-/-/lacZ reporter mice and showed that lacZ was strongly expressed in the cortex, the dentate gyrus, the CA1 and CA2 regions of the hippocampus, the thalamus, and the olfactory bulb. Immunohistochemistry and western blotting confirmed this pattern and revealed expression of EFhd2 during neuronal maturation. In cortical neurons, EFhd2 was detected in neurites marked by MAP2 and co-localized with preand post-synaptic markers. Approximately one third of EFhd2 associated with a biochemically isolated synaptosome preparation. There, EFhd2 was mostly confined to the cytosolic and plasma membrane fractions. Both synaptic endocytosis and exocytosis in primary hippocampal EFhd2-/- neurons were unaltered but transport of synaptophysin-GFP containing vesicles was enhanced in EFhd2-/- primary hippocampal neurons, and notably, EFhd2 inhibited kinesin mediated microtubule gliding. Therefore, we found that EFhd2 is a neuronal protein that interferes with kinesin-mediated transport.Peer reviewe

Alzheimer’s disease in humans and other animals; a consequence of post-reproductive lifespan and longevity rather than ageing

Two diseases of the modern world – Alzheimer’s and diabetes mellitus – are linked by epidemiology, genetics and molecular pathogenesis. They may also be linked by the remarkable observation that insulin signaling sets the limits on longevity. In worms, flies and mice, disrupting insulin signaling increases lifespan leading some to speculate that caloric restriction might extend lifespan in man. It is our contention that man is already a long lived organism, specifically with a remarkably high post-fertility life span, and that it is this that results in the high prevalence of Alzheimer’s and diabetes. We review evidence for this hypothesis that carries specific predictions including that other animals with exceptionally long post-reproductive lifespan will have increased risk of both diabetes and Alzheimer’s disease and present novel evidence that Dolphin, like man, an animal with exceptional longevity, might be one of the very few natural models of Alzheimer’s disease

The velocity peaks in the cold dark matter spectrum on Earth

The cold dark matter spectrum on earth is expected to have peaks in velocity space. We obtain estimates for the sizes and locations of these peaks. To this end we have generalized the secondary infall model of galactic halo formation to include angular momentum of the dark matter particles. This new model is still spherically symmetric and it has self-similar solutions. Our results are relevant to direct dark matter search experiments.Comment: 12 pages including 1 table and 4 figures, LaTeX, REVTEX 3.0 versio

Quantum Phases of Vortices in Rotating Bose-Einstein Condensates

We investigate the groundstates of weakly interacting bosons in a rotating trap as a function of the number of bosons, $N$, and the average number of vortices, $N_V$. We identify the filling fraction $\nu\equiv N/N_V$ as the parameter controlling the nature of these states. We present results indicating that, as a function of $\nu$, there is a zero temperature {\it phase transition} between a triangular vortex lattice phase, and strongly-correlated vortex liquid phases. The vortex liquid phases appear to be the Read-Rezayi parafermion states

A multiscale approach to environment and its influence on the colour distribution of galaxies

We present a multiscale approach to measurements of galaxy density, applied to a volume-limited sample constructed from SDSS DR5. We populate a rich parameter space by obtaining independent measurements of density on different scales for each galaxy, avoiding the implicit assumptions involved, e.g., in the construction of group catalogues. As the first application of this method, we study how the bimodality in galaxy colour distribution (u-r) depends on multiscale density. The u-r galaxy colour distribution is described as the sum of two gaussians (red and blue) with five parameters: the fraction of red galaxies (f_r) and the position and width of the red and blue peaks (mu_r, mu_b, sigma_r and sigma_b). Galaxies mostly react to their smallest scale (< 0.5 Mpc) environments: in denser environments red galaxies are more common (larger f_r), redder (larger mu_r) and with a narrower distribution (smaller sigma_r), while blue galaxies are redder (larger mu_b) but with a broader distribution (larger sigma_b). There are residual correlations of f_r and mu_b with 0.5 - 1 Mpc scale density, which imply that total or partial truncation of star formation can relate to a galaxy's environment on these scales. Beyond 1 Mpc (0.5 Mpc for mu_r) there are no positive correlations with density. However f_r (mu_r) anti-correlates with density on >2 (1) Mpc scales at fixed density on smaller scales. We examine these trends qualitatively in the context of the halo model, utilizing the properties of haloes within which the galaxies are embedded, derived by Yang et al, 2007 and applied to a group catalogue. This yields an excellent description of the trends with multiscale density, including the anti-correlations on large scales, which map the region of accretion onto massive haloes. Thus we conclude that galaxies become red only once they have been accreted onto haloes of a certain mass.Comment: 22 pages, 14 figures. Accepted for publication in MNRAS

Properties of satellite galaxies in the SDSS photometric survey: luminosities, colours and projected number density profiles

We analyze photometric data in SDSS-DR7 to infer statistical properties of faint satellites associated to isolated bright galaxies (M_r<-20.5) in the redshift range 0.03<z<0.1. The mean projected radial profile shows an excess of companions in the photometric sample around the primaries, with approximately a power law shape that extends up to ~700kpc. Given this overdensity signal, a suitable background subtraction method is used to study the statistical properties of the population of bound satellites, down to magnitude M_r=-14.5, in the projected radial distance range 100 < r_p/kpc < 3 R_{vir}. We have also considered a color cut consistent with the observed colors of spectroscopic satellites in nearby galaxies so that distant redshifted galaxies do not dominate the statistics. We have tested the implementation of this procedure using a mock catalog. We find that the method is effective in reproducing the true projected radial satellite number density profile and luminosity distributions, providing confidence in the results derived from SDSS data. The spatial extent of satellites is larger for bright, red primaries. Also, we find a larger spatial distribution of blue satellites. For the different samples analyzed, we derive the average number of satellites and their luminosity distributions down to M_r=-14.5. The mean number of satellites depends very strongly on host luminosity. Bright primaries (M_r<-21.5) host on average ~6 satellites with M_r<-14.5, while primaries with -21.5<M_r<-20.5 have less than 1 satellite per host. We provide Schechter function fits to the luminosity distributions of satellite galaxies with faint-end slopes -1.3+/-0.2. This shows that satellites of bright primaries lack an excess population of faint objects, in agreement with the results in the Milky Way and nearby galaxies.Comment: 14 pages, 13 figures. Accepted for publication in Astronomical Journa

Halo mass - concentration relation from weak lensing

We perform a statistical weak lensing analysis of dark matter profiles around tracers of halo mass from galactic- to cluster-size halos. In this analysis we use 170,640 isolated ~L* galaxies split into ellipticals and spirals, 38,236 groups traced by isolated spectroscopic Luminous Red Galaxies (LRGs) and 13,823 MaxBCG clusters from the Sloan Digital Sky Survey (SDSS) covering a wide range of richness. Together these three samples allow a determination of the density profiles of dark matter halos over three orders of magnitude in mass, from 10^{12} M_{sun} to 10^{15} M_{sun}. The resulting lensing signal is consistent with an NFW or Einasto profile on scales outside the central region. We find that the NFW concentration parameter c_{200b} decreases with halo mass, from around 10 for galactic halos to 4 for cluster halos. Assuming its dependence on halo mass in the form of c_{200b} = c_0 [M/(10^{14}M_{sun}/h)]^{\beta}, we find c_0=4.6 +/- 0.7 (at z=0.22) and \beta=0.13 +/- 0.07, with very similar results for the Einasto profile. The slope (\beta) is in agreement with theoretical predictions, while the amplitude is about two standard deviations below the predictions for this mass and redshift, but we note that the published values in the literature differ at a level of 10-20% and that for a proper comparison our analysis should be repeated in simulations. We discuss the implications of our results for the baryonic effects on the shear power spectrum: since these are expected to increase the halo concentration, the fact that we see no evidence of high concentrations on scales above 20% of the virial radius suggests that baryonic effects are limited to small scales, and are not a significant source of uncertainty for the current weak lensing measurements of the dark matter power spectrum. [ABRIDGED]Comment: 17 pages, 5 figures, accepted to JCAP pending minor revisions that are included in v2 here on arXi