1,930 research outputs found
Epigenetics, Responsiveness and Embodiment
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
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
Use of attribute association error probability estimates to evaluate quality of medical record geocodes
BACKGROUND: The utility of patient attributes associated with the spatiotemporal analysis of medical records lies not just in their values but also the strength of association between them. Estimating the extent to which a hierarchy of conditional probability exists between patient attribute associations such as patient identifying fields, patient and date of diagnosis, and patient and address at diagnosis is fundamental to estimating the strength of association between patient and geocode, and patient and enumeration area. We propose a hierarchy for the attribute associations within medical records that enable spatiotemporal relationships. We also present a set of metrics that store attribute association error probability (AAEP), to estimate error probability for all attribute associations upon which certainty in a patient geocode depends. METHODS: A series of experiments were undertaken to understand how error estimation could be operationalized within health data and what levels of AAEP in real data reveal themselves using these methods. Specifically, the goals of this evaluation were to (1) assess if the concept of our error assessment techniques could be implemented by a population-based cancer registry; (2) apply the techniques to real data from a large health data agency and characterize the observed levels of AAEP; and (3) demonstrate how detected AAEP might impact spatiotemporal health research. RESULTS: We present an evaluation of AAEP metrics generated for cancer cases in a North Carolina county. We show examples of how we estimated AAEP for selected attribute associations and circumstances. We demonstrate the distribution of AAEP in our case sample across attribute associations, and demonstrate ways in which disease registry specific operations influence the prevalence of AAEP estimates for specific attribute associations. CONCLUSIONS: The effort to detect and store estimates of AAEP is worthwhile because of the increase in confidence fostered by the attribute association level approach to the assessment of uncertainty in patient geocodes, relative to existing geocoding related uncertainty metrics
Contribution of Direct Heating, Thermal Conduction and Perfusion During Radiofrequency and Microwave Ablation
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
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
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
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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