Assessing acute itch intensity : general labelled magnitude scale is more reliable than classic visual analogue scale

The reliable measurement of itch intensity is crucial, both in research as well as clinical contexts. For example, when the reliability of a measurement scale is unknown, it is impossible to determine whether a patient has changed sufficiently to be confident that the change is beyond that which could be attributed to measurement error (1). One factor that might influence the reliability of measurements is the type of rating scale used to assess itch intensity. Previous research (2-4) has documented the retest reliability of different rating scales for assessing chronic itch intensity. However, a retest reliability analysis of rating scales for acute experimental itch, induced using substances such as histamine or cowhage, is currently lacking. Here, we compare the test-retest reliability of three rating scales commonly used for this purpose. First, we considered the visual analogue scale in its classic form (cVAS), where participants indicate itch intensity on a line ranging from 0 (no itch) to 100 (the most intense itch imaginable). Second, we included a variant of the VAS, where an additional ‘Scratch Threshold’ marker is set at 33% (tVAS,5), defined as itching strong enough to be scratched (6). Finally, we considered the general Labelled Magnitude Scale (gLMS,7), where participants judge the magnitude of itch on a line with quasilogarithmically placed labels of “no sensation” at 0, “barely detectable” at 1, “weak” at 6, “moderate” at 17, “strong” at 35, “very strong” at 53 and “strongest imaginable sensation” at 100. Thus, all three scales have an identical range, but differ in the type and number of verbal labels provided

Cluster Structure in Cosmological Simulations I: Correlation to Observables, Mass Estimates, and Evolution

We use Enzo, a hybrid Eulerian AMR/N-body code including non-gravitational heating and cooling, to explore the morphology of the X-ray gas in clusters of galaxies and its evolution in current generation cosmological simulations. We employ and compare two observationally motivated structure measures: power ratios and centroid shift. Overall, the structure of our simulated clusters compares remarkably well to low-redshift observations, although some differences remain that may point to incomplete gas physics. We find no dependence on cluster structure in the mass-observable scaling relations, T_X-M and Y_X-M, when using the true cluster masses. However, estimates of the total mass based on the assumption of hydrostatic equilibrium, as assumed in observational studies, are systematically low. We show that the hydrostatic mass bias strongly correlates with cluster structure and, more weakly, with cluster mass. When the hydrostatic masses are used, the mass-observable scaling relations and gas mass fractions depend significantly on cluster morphology, and the true relations are not recovered even if the most relaxed clusters are used. We show that cluster structure, via the power ratios, can be used to effectively correct the hydrostatic mass estimates and mass-scaling relations, suggesting that we can calibrate for this systematic effect in cosmological studies. Similar to observational studies, we find that cluster structure, particularly centroid shift, evolves with redshift. This evolution is mild but will lead to additional errors at high redshift. Projection along the line of sight leads to significant uncertainty in the structure of individual clusters: less than 50% of clusters which appear relaxed in projection based on our structure measures are truly relaxed.Comment: 57 pages, 18 figures, accepted to ApJ, updated definition of T_X and M_gas but results unchanged, for version with full resolution figures, see http://www.ociw.edu/~tesla/sims.ps.g

Spatial Probability Distribution of Adsorbate Atoms

In order to access the dynamics of surface diffusion or of surface chemical reactions it is necessary to determine the spatial probability distributions of the adsorbed atoms or molecules rather than their average positions. Here we demonstrate how such a distribution can be determined from scanned-energy mode photoelectron diffraction data using the maximum entropy method. As a test case we have chosen the distribution of the carbon atom in the methoxy species adsorbed on Ni(111). Both simulated and experimental data are used

Automatic detection of arcs and arclets formed by gravitational lensing

We present an algorithm developed particularly to detect gravitationally lensed arcs in clusters of galaxies. This algorithm is suited for automated surveys as well as individual arc detections. New methods are used for image smoothing and source detection. The smoothing is performed by so-called anisotropic diffusion, which maintains the shape of the arcs and does not disperse them. The algorithm is much more efficient in detecting arcs than other source finding algorithms and the detection by eye.Comment: A&A in press, 12 pages, 16 figure

Temperature oscillation coupled with fungal community shifts can modulate warming effects on litter decomposition

Diel temperature oscillations are a nearly ubiquitous phenomenon, with amplitudes predicted to change along with mean temperatures under global-warming scenarios. Impact assessments of global warming have largely disregarded diel temperature oscillations, even though key processes in ecosystems, such as decomposition, may be affected. We tested the effect of a 5 degrees C temperature increase with and without diel oscillations on litter decomposition by fungal communities in stream microcosms. Five temperature regimes with identical thermal sums (degree days) were applied: constant 3 degrees and 8 degrees C; diel temperature oscillations of 5 degrees C around each mean; and oscillations of 9 degrees C around 8 degrees C. Temperature oscillations around 8 degrees C (warming scenario), but not 3 degrees C (ambient scenario), accelerated decomposition by 18% (5 degrees C oscillations) and 31% (9 degrees C oscillations), respectively, compared to the constant temperature regime at 8 degrees C. Community structure was not affected by oscillating temperatures, although the rise in mean temperature from 3 degrees to 8 degrees C consistently shifted the relative abundance of species. A simple model using temperature-growth responses of the dominant fungal decomposers accurately described the experimentally observed pattern, indicating that the effect of temperature oscillations on decomposition in our warming scenario was caused by strong curvilinear responses of species to warming at low temperature, particularly of the species becoming most abundant at 8 degrees C (Tetracladium marchalianum). These findings underscore the need to consider species-specific temperature characteristics in concert with changes in communities when assessing consequences of global warming on ecosystem processes

The Dwarf Irregular Galaxy UGC 7636 Exposed: Stripping At Work In The Virgo Cluster

We present the results of optical spectroscopy of a newly discovered H II region residing in the H I gas cloud located between the dwarf irregular galaxy UGC 7636 and the giant elliptical galaxy NGC 4472 in the Virgo Cluster. By comparing UGC 7636 with dwarf irregular galaxies in the field, we show that the H I cloud must have originated from UGC 7636 because (1) the oxygen abundance of the cloud agrees with that expected for a galaxy with the blue luminosity of UGC 7636, and (2) M_{H I}/L_B for UGC 7636 becomes consistent with the measured oxygen abundance of the cloud if the H I mass of the cloud is added back into UGC 7636. It is likely that tides from NGC 4472 first loosened the H I gas, after which ram-pressure stripping removed the gas from UGC 7636.Comment: 12 pages, 2 eps figures (AASTeX 5.0); accepted for publication in ApJ Letter