1,920 research outputs found

    Epigenetics, Responsiveness and Embodiment

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    This short paper comments on the connections between epigenetics, responsiveness and embodiment. Epigenetics has solidified a new conception of DNA as “responsive,” and rightfully so. Yet, the discussion too easily falls back to metaphors of agency and can show a tendency to see responsiveness and embodiment as based on epigenetics, which is shown to be wrong

    Photometric Properties of Void Galaxies in the Sloan Digital Sky Survey DR7 Data Release

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    Using the sample presented in Pan:2011, we analyse the photometric properties of 88,794 void galaxies and compare them to galaxies in higher density environments with the same absolute magnitude distribution. In Pan et al. (2011), we found a total of 1054 dynamically distinct voids in the SDSS with radius larger than 10h^-1 Mpc. The voids are underdense, with delta rho/rho < -0.9 in their centers. Here we study the photometric properties of these void galaxies. We look at the u - r colours as an indication of star formation activity and the inverse concentration index as an indication of galaxy type. We find that void galaxies are statistically bluer than galaxies found in higher density environments with the same magnitude distribution. We examine the colours of the galaxies as a function of magnitude, and we fit each colour distribution with a double-Gaussian model for the red and blue subpopulations. As we move from bright to dwarf galaxies, the population of red galaxies steadily decreases and the fraction of blue galaxies increases in both voids and walls, however the fraction of blue galaxies in the voids is always higher and bluer than in the walls. We also split the void and wall galaxies into samples depending on galaxy type. We find that late type void galaxies are bluer than late type wall galaxies and the same holds for early galaxies. We also find that early type, dwarf void galaxies are blue in colour. We also study the properties of void galaxies as a function of their distance from the center of the void. We find very little variation in the properties, such as magnitude, colour and type, of void galaxies as a function of their location in the void. The only exception is that the dwarf void galaxies may live closer to the center. The centers of voids have very similar density contrast and hence all void galaxies live in very similar density environments (ABRIDGED)Comment: 10 pages, 25 figure

    Contribution of Direct Heating, Thermal Conduction and Perfusion During Radiofrequency and Microwave Ablation

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    Both radiofrequency (RF) and microwave (MW) ablation devices are clinically used for tumor ablation. Several studies report less dependence on vascular mediated cooling of MW compared to RF ablation. We created computer models of a cooled RF needle electrode, and a dipole MW antenna to determine differences in tissue heat transfer

    Spatial and Dynamical Properties of Voids in a LCDM Universe

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    We study statistical properties of voids in the distribution of mass, dark-matter haloes and galaxies (B_J<-16) in a LCDM numerical simulation populated with galaxies using a semi-analytic galaxy formation model(GALFORM, Cole et al. 2000). We find that the properties of voids selected from GALFORM galaxies are compatible with those of voids identified from a population of haloes with mass M>10^11.5 M_sun/h, similar to the median halo mass, M_med=10^11.3 M_sun/h. We also find that the number density of galaxy- and halo-defined voids can be up to two orders of magnitude higher than mass-defined voids for large void radii. As expected, there are outflow velocities which show their maximum at larger void-centric distances for larger voids (well described by a linear relation). The void-centric distance where this maximum occurs, follows a suitable power law fit of the form, log(d_vmax)=(r_void/A)^B. At sufficiently large distances, we find mild infall motions onto the sub-dense regions. We find that a similar analysis in redshift space would make both outflows and infalls to appear with a lower amplitude. We also find that the velocity dispersion of galaxies and haloes is larger in the direction parallel to the void walls by ~10-20%. We analyse the void-tracer cross-correlation functions in real- and redshift-space as a function of separation, and also as a function of separations parallel and perpendicular to the line of sight. The distortion pattern observed in xi(sigma,pi) is that of an elongation along the line of sight which extends out to large separations. Positive xi contours evidence finger-of-god motions at the void walls. Elongations along the line of sight are roughly comparable between galaxy-, halo- and mass-defined voids. (Abridged)Comment: 16 pages, 11 figures, accepted for Publication in MNRA

    Large-scale modulation of star formation in void walls

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    We perform a statistical study of the characteristics of galaxies in voids and void walls in the SDSS and 2dFGRS catalogues. We investigate dependencies of the distribution of galaxy spectral types and colours as a function of the relative position to the void centres for different luminosity and local density ranges. We find a trend towards bluer, star forming galaxies in void walls beyond the local density dependence. These results indicate that luminosity and local density do not entirely determine the distribution of galaxy properties such as colours and spectral types, and point towards a large scale modulation of star formation. We argue that this effect is due to the lower accretion and merger history of galaxies arriving at void walls from the emptier inner void regions.Comment: 5 pages, 6 figures, submitted to MRNAS Letter

    Pleural Mesothelioma in New Caledonia: Associations with Environmental Risk Factors

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    International audienceBackground: High incidences of malignant mesothelioma (MM) have been observed in New Caledonia. Previous work has shown an association between MM and soil containing serpentinite. Objectives: We studied the spatial and temporal variation of MM and its association with environmental factors. Methods: We investigated the 109 MM cases recorded in the Cancer Registry of New Caledonia between 1984 and 2008 and performed spatial, temporal, and space-time cluster analyses. We conducted an ecological analysis involving 100 tribes over a large area including those with the highest incidence rates. Associations with environmental factors were assessed using logistic and Poisson regression analyses. Results: The highest incidence was observed in the HouaĂŻlou area with a world age-standardized rate of 128.7 per 100,000 person-years [95% confidence interval (CI), 70.41-137.84]. A significant spatial cluster grouped 18 tribes (31 observed cases vs. 8 expected cases; p = 0.001), but no significant temporal clusters were identified. The ecological analyses identified serpentinite on roads as the greatest environmental risk factor (odds ratio = 495.0; 95% CI, 46.2-4679.7; multivariate incidence rate ratio = 13.0; 95% CI, 10.2-16.6). The risk increased with serpentinite surface, proximity to serpentinite quarries and distance to the peridotite massif. The association with serpentines was stronger than with amphiboles. Living on a slope and close to dense vegetation appeared protective. The use of whitewash, previously suggested to be a risk factor, was not associated with MM incidence. Conclusions: Presence of serpentinite on roads is a major environmental risk factor for mesothelioma in New Caledonia
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