Preprotachykinin A (PPTA) is expressed by a distinct population of excitatory neurons in the mouse superficial spinal dorsal horn including cells that respond to noxious and pruritic stimuli

The superficial dorsal horn, which is the main target for nociceptive and pruritoceptive primary afferents, contains a high density of excitatory interneurons. Our understanding of their roles in somatosensory processing has been restricted by the difficulty of distinguishing functional populations among these cells. We recently defined three non-overlapping populations among the excitatory neurons, based on the expression of neurotensin, neurokinin B (NKB) and gastrin-releasing peptide (GRP). Here we identify and characterise another population: neurons that express the tachykinin peptide substance P. We show with immunocytochemistry that its precursor protein (preprotachykinin A, PPTA) can be detected in ~14% of lamina I-II neurons, and these are concentrated in the outer part of lamina II. Over 80% of the PPTA-positive cells lack the transcription factor Pax2 (which determines an inhibitory phenotype), and these account for ~15% of the excitatory neurons in this region. They are different from the neurotensin, NKB or GRP neurons, although many of them contain somatostatin, which is widely expressed among superficial dorsal horn excitatory interneurons. We show that many of these cells respond to noxious thermal and mechanical stimuli, and to intradermal injection of pruritogens. Finally, we demonstrate that these cells can also be identified in a knock-in Cre mouse line (Tac1Cre), although our findings suggest that there is an additional population of neurons that transiently express PPTA. This population of substance P-expressing excitatory neurons is likely to play an important role in transmission of signals that are perceived as pain and itch

A quantitative study of neurochemically-defined populations of inhibitory interneurons in the superficial dorsal horn of the mouse spinal cord

Around a quarter of neurons in laminae I-II of the dorsal horn are inhibitory interneurons. These play an important role in modulating somatosensory information, including that perceived as pain or itch. Previous studies in rat identified four largely non-overlapping neurochemical populations among these cells, defined by expression of galanin, neuropeptide Y (NPY), neuronal nitric oxide synthase (nNOS) or parvalbumin. The galanin cells were subsequently shown to coexpress dynorphin. Several recent studies have used genetically-modified mice to investigate the function of different interneuron populations, and it is therefore important to determine whether the same pattern applies in mouse, and to estimate the relative sizes of these populations. We show that the neurochemical organisation of inhibitory interneurons in mouse superficial dorsal horn is similar to that in the rat, although a larger proportion of these neurons (33%) express NPY. Between them, these four populations account for ∼75% of inhibitory cells in laminae I-II. Since ∼25% of inhibitory interneurons in this region belong to a novel calretinin-expressing type, our results suggest that virtually all inhibitory interneurons in superficial dorsal horn can be assigned to one of these five neurochemical populations. Although our main focus was inhibitory neurons, we also identified a population of excitatory dynorphin-expressing cells in laminae I-II that are largely restricted to the medial part of the mid-lumbar dorsal horn, corresponding to glabrous skin territory. These findings are important for interpretation of studies using molecular-genetic techniques to manipulate the functions of interneuron populations to investigate their roles in somatosensory processing

A survey for large image-separation lensed quasars

The statistics of gravitationally lensed quasars with multiple images in the 0.1''-7'' range have been measured in various surveys. Little is known, however, about lensed-quasar statistics at larger image separations, which probe masses on the scale of galaxy clusters. We extend the results of the HST Snapshot Survey for Lensed Quasars to the 7''-50'' range for a sub-sample of 76 quasars that is free of known selection effects. Using a combination of multicolor photometry and spectroscopy, we show that none of the point sources in the entire field of view of the HST observations of these quasars are lensed images. Large-separation quasar lensing is therefore not common. We carry out a detailed calculation of the expected statistics of large-separation lensing for this quasar sample, incorporating realistic input for the mass profiles and mass function of galaxy clusters. We find that the observational null results are consistent with the expected effect of galaxy clusters, even if these have existed in their present form and number since z of about 2. The rarity of large-separation lensed quasars can rule out some extreme scenarios, e.g. that the mass-function of clusters has been severely underestimated, or that large mass concentrations that are not associated with galaxies (i.e. ``failed'' clusters) are common. The rareness of wide lensing also sets limits on the cosmological constant that are independent of limits derived from galaxy lensing. The lensing statistics of larger quasar samples can probe the structure, number, and evolution of clusters, as well as the geometry of space.Comment: LaTex, ApJ, submitte

PNF 2.0? Initial evidence that gamification can increase the efficacy of brief, web-based personalized normative feedback alcohol interventions

Gamified interventions exploit the motivational characteristics of a game in order to provide prevention information and promote behavior change. Despite the modest effect sizes observed in increasingly popular web-based personalized normative feedback (PNF) alcohol interventions for college students, previous research has yet to consider how gamification might be used to enhance efficacy. This study examines whether a novel, gamified PNF intervention format, which includes a point-based reward system, the element of chance, and personal icons to visually represent users, is more effective in reducing short-term alcohol use than the standard web-based style of PNF currently used on college campuses. Two-hundred and thirty-seven college students were randomly assigned to receive either a standard brief, web-based PNF alcohol intervention or the same alcohol intervention components delivered within a Facebook-connected social game called CampusGANDR (Gamified Alcohol Norm Discovery and Readjustment). In both study conditions participants answered identical questions about their perceptions of peer drinking norms and own drinking and then received the same PNF slides. Two weeks following PNF delivery, participants again reported their perceptions of peers\u27 alcohol use and own drinking. Students in the CampusGANDR condition reported significantly reduced peer drinking norms and alcohol use at the two-week follow-up relative to students who received identical PNF delivered by standard online survey. Further, a mediation model demonstrated that this effect was driven by larger reductions in perceived drinking norms among participants assigned to receive CampusGANDR, relative to control. As web-based PNF is becoming an increasingly universal prevention strategy, findings from this study suggest gamification may represent one method by which intervention efficacy could be substantially improved. The potential methodological and economic benefits associated with gamified PNF interventions are emphasized and directions for future research are discussed

Resolving the Stellar Populations in a z=4 Lensed Galaxy

We present deep near-infrared Keck/NIRC imaging of a recently-discovered z=4.04 galaxy (Frye & Broadhurst 1998). This is lensed by the rich foreground cluster Abell~2390 (z~0.23) into highly-magnified arcs 3-5arcsec in length. Our H- and K'-band NIRC imaging allows us to map the Balmer+4000Ang break amplitude. In combination with high-quality archival HST/WFPC2 data, we can spatially resolve stellar populations along the arcs. The WFPC2 images clearly reveal several bright knots, which correspond to sites of active star formation. However, there are considerable portions of the arcs are significantly redder, consistent with being observed >100Myr after star formation has ceased. Keck/LRIS long-slit spectroscopy along the arcs reveals that the Ly-alpha emission is spatially offset by ~1arcsec from the rest-UV continuum regions. We show that this line emission is most probably powered by star formation in neighboring HII regions, and that the z=4 system is unlikely to be an AGN.Comment: Accepted for publication in the Astrophysical Journal. Uses emulateapj.sty and graphics.sty (included). 34 pages - has 5 tables and 21 encapsulated postscript figures, 4 in colour mail (B&W versions also provided

An HST/WFPC2 Snapshot Survey of 2MASS-Selected Red QSOs

Using simple infrared color selection, 2MASS has found a large number of red, previously unidentified, radio-quiet QSOs. Although missed by UV/optical surveys, the 2MASS QSOs have K-band luminosities that are comparable to "classical" QSOs. This suggests the possible discovery of a previously predicted large population of dust-obscured radio-quiet QSOs. We present the results of an imaging survey of 29 2MASS QSOs observed with WFPC2 onboard the Hubble Space Telescope. I-band images, which benefit from the relative faintness of the nuclei at optical wavelengths, are used to characterize the host galaxies, measure the nuclear contribution to the total observed I-band emission, and to survey the surrounding environments. The 2MASS QSOs are found to lie in galaxies with a variety of morphologies, luminosities, and dynamical states, not unlike those hosting radio-quiet PG QSOs. Our analysis suggests that the extraordinary red colors of the 2MASS QSOs are caused by extinction of an otherwise typical QSO spectrum due to dust near the nucleus.Comment: 23 pages including 9 figures and 7 tables, accepted for publication in ApJ, higher resolution HST images at: http://shapley.as.arizona.edu/~amarble/papers/twomq

Radio Observations of the Hubble Deep Field South region: I. Survey Description and Initial Results

This paper is the first of a series describing the results of the Australia Telescope Hubble Deep Field South (ATHDFS) radio survey. The survey was conducted at four wavelengths - 20, 11, 6, and 3 cm, over a 4-year period, and achieves an rms sensitivity of about 10 microJy at each wavelength. We describe the observations and data reduction processes, and present data on radio sources close to the centre of the HDF-S. We discuss in detail the properties of a subset of these sources. The sources include both starburst galaxies and galaxies powered by an active galactic nucleus, and range in redshift from 0.1 to 2.2. Some of them are characterised by unusually high radio-to-optical luminosities, presumably caused by dust extinction.Comment: Accepted by AJ. 32 pages, 4 tables, 3 figures. PDF with full-resolution figures is on http://www.atnf.csiro.au/people/rnorris/N197.pd

Neutral kaon mixing beyond the Standard Model with nf=2+1 chiral fermions part II:Non Perturbative Renormalisation of the ΔF=2 four-quark operators

We compute the renormalisation factors (Z-matrices) of the $\Delta F=2$ four-quark operators needed for Beyond the Standard Model (BSM) kaon mixing. We work with nf=2+1 flavours of Domain-Wall fermions whose chiral-flavour properties are essential to maintain a continuum-like mixing pattern. We introduce new RI-SMOM renormalisation schemes, which we argue are better behaved compared to the commonly-used corresponding RI-MOM one. We find that, once converted to MS, the Z-factors computed through these RI-SMOM schemes are in good agreement but differ significantly from the ones computed through the RI-MOM scheme. The RI-SMOM Z-factors presented here have been used to compute the BSM neutral kaon mixing matrix elements in the companion paper [1]. We argue that the renormalisation procedure is responsible for the discrepancies observed by different collaborations, we will investigate and elucidate the origin of these differences throughout this work