Use of the Fluorescence-Activated Cell Sorter to Quantitate and Enrich for Subpopulations of Human Skin Cells

A variety of immunologic staining techniques were compared in a quantitative study of antigen expression by human epidermal cells. Virtually all nucleated epidermal cells express β2-microglobulin, which is associated with HLA-A, -B, and -C antigens, whereas only about 4% expressed T6, an antigen expressed by Langerhans cells but not other cells in the skin. With the fluorescence-activated cell sorter (FACS), epidermal cell suspensions were selectively enriched 10- to 15-fold for T6-positive Langerhans cells.An average of 6.5% of cells were specifically stained by anti-HLA-DR antibody. When dispersed cells stained with anti-DR plus peroxidase were examined with the technique of immunoelectron microscopy, only mononuclear leukocytes (probably Langerhans cells) were stained. After separating HLA-DR positive skin cells with the FACS, the DR-positive population but not the DR-negative population stimulated proliferation of allogeneic responder lymphocytes, indicating that sorted cells are metabolically active. We conclude that HLA-DR antigen is not expressed by keratinocytes in normal human skin cell suspensions and that the FACS can be used to selectively enrich or deplete skin cell suspensions of antigenically distinct subpopulations such as Langerhans cells

Temperature Fluctuations and Abundances in HII Galaxies

There is evidence for temperature fluctuations in Planetary Nebulae and in Galactic HII regions. If such fluctuations occur in the low-metallicity, extragalactic HII regions used to probe the primordial helium abundance, the derived 4He mass fraction, Y_P, could be systematically different from the true primordial value. For cooler, mainly high-metallicity HII regions the derived helium abundance may be nearly unchanged but the oxygen abundance could have been seriously underestimated. For hotter, mainly low-metallicity HII regions the oxygen abundance is likely accurate but the helium abundance could be underestimated. The net effect is to tilt the Y vs. Z relation, making it flatter and resulting in a higher inferred Y_P. Although this effect could be large, there are no data which allow us to estimate the size of the temperature fluctuations for the extragalactic HII regions. Therefore, we have explored this effect via Monte Carlos in which the abundances derived from a fiducial data set are modified by \Delta-T chosen from a distribution with 0 < \Delta-T < \Delta-T_max where \Delta-T_max is varied from 500K to 4000K. It is interesting that although this effect shifts the locations of the HII regions in Y vs. O/H plane, it does not introduce any significant additional dispersion.Comment: 11 pages, 9 postscript figures; submitted to the Ap

Risk Tolerance, Self-Interest, and Social Preferences

We use an experimental method to investigate whether systematic relationships exist across distinct aspects of individual preferences: risk aversion in monetary outcomes, altruism in a twoperson context, and social preferences in a larger group context. Individual preferences across these three contexts are measured, and there is no possibility for risk sharing, wealth effects, or updating expectations of the population choices. We find that social preferences are related to demographic variables, including years of education, gender, and age. Perhaps most importantly, self allocation in a two-person dictator game is related to social preferences in a group context. Participants who are more generous in a dictator game are more likely to vote against their selfinterest in a group decision-making task which we interpret to be expressions of social preferences

Four quasars above redshift 6 discovered by the Canada-France High-z Quasar Survey

The Canada-France High-z Quasar Survey (CFHQS) is an optical survey designed to locate quasars during the epoch of reionization. In this paper we present the discovery of the first four CFHQS quasars at redshift greater than 6, including the most distant known quasar, CFHQS J2329-0301 at z=6.43. We describe the observational method used to identify the quasars and present optical, infrared, and millimeter photometry and optical and near-infrared spectroscopy. We investigate the dust properties of these quasars finding an unusual dust extinction curve for one quasar and a high far-infrared luminosity due to dust emission for another. The mean millimeter continuum flux for CFHQS quasars is substantially lower than that for SDSS quasars at the same redshift, likely due to a correlation with quasar UV luminosity. For two quasars with sufficiently high signal-to-noise optical spectra, we use the spectra to investigate the ionization state of hydrogen at z>5. For CFHQS J1509-1749 at z=6.12, we find significant evolution (beyond a simple extrapolation of lower redshift data) in the Gunn-Peterson optical depth at z>5.4. The line-of-sight to this quasar has one of the highest known optical depths at z~5.8. An analysis of the sizes of the highly-ionized near-zones in the spectra of two quasars at z=6.12 and z=6.43 suggest the IGM surrounding these quasars was substantially ionized before these quasars turned on. Together, these observations point towards an extended reionization process, but we caution that cosmic variance is still a major limitation in z>6 quasar observations.Comment: 15 pages, 9 figures, AJ, in press, minor changes to previous versio

Does wage rank affect employees' well-being?

How do workers make wage comparisons? Both an experimental study and an analysis of 16,000 British employees are reported. Satisfaction and well-being levels are shown to depend on more than simple relative pay. They depend upon the ordinal rank of an individual's wage within a comparison group. “Rank” itself thus seems to matter to human beings. Moreover, consistent with psychological theory, quits in a workplace are correlated with pay distribution skewness

Responses to Selection for Partial Resistance to Crown Rust in Oat

Crown rust, caused by the fungal pathogen, Puccinia coronata Corda var. avenae W.P. Fraser Ledingham, reduces kernel quality and grain yield in oat (Avena sativa L.). Partial resistance is considered to be a durable form of rust resistance. This study sought to evaluate the feasibility of simultaneously improving partial resistance to crown rust, grain yield, and seed weight in an oat population, and to estimate predicted and realized heritabilities for area under disease progress curve (AUDPC) and genetic correlations between AUDPC and agronomic traits in both crown rust-inoculated and fungicide-treated plots. A single cycle of selection for partial resistance to crown rust was performed. The initial (C0) and selected (C1) generations were evaluated in a field experiment in 2001 and 2002 at two Iowa locations. Selection on an index increased the levels of crown rust resistance, grain yield, and seed weight in crown rust−inoculated plots, and seed weight in fungicide-treated plots. However, the change for the grain yield in fungicide-treated plots was not significant. In both C0 and C1 populations, AUDPC was highly heritable (H = 0.77 and 0.78 respectively), and was favorably correlated with grain yield, seed weight, and test weight measured in inoculated plots. Realized heritabilities for all traits except grain yield under fungicide treatment were consistent with predicted heritabilities. Our results suggested that index selection could increase levels of crown rust resistance, grain yield, and seed weight simultaneously

CACHD1 is an α2δ-like protein that modulates CaV3 voltage-gated calcium channel activity

The putative cache (Ca2+ channel and chemotaxis receptor) domain containing 1 (CACHD1) protein has predicted structural similarities to members of the alpha2delta voltage-gated Ca2+ channel (VGCC) auxiliary subunit family. CACHD1 mRNA and protein were highly expressed in the male mammalian CNS, in particular in the thalamus, hippocampus and cerebellum, with a broadly similar tissue distribution to CaV3 subunits, in particular, CaV3.1. In expression studies, CACHD1 increased cell-surface localization of CaV3.1 and these proteins were in close proximity at the cell surface consistent with the formation of CACHD1-CaV3.1 complexes. In functional electrophysiological studies, co-expression of human CACHD1 with CaV3.1, CaV3.2 and CaV3.3 caused a significant increase in peak current density and corresponding increases in maximal conductance. By contrast, alpha2delta-1 had no effect on peak current density or maximal conductance in either CaV3.1, CaV3.2 or CaV3.3. Comparison of CACHD1-mediated increases in CaV3.1 current density and gating currents revealed an increase in channel open probability. In hippocampal neurons from male and female E19 rats, CACHD1 overexpression increased CaV3-mediated action potential (AP) firing frequency and neuronal excitability. These data suggest that CACHD1 is structurally an alpha2delta-like protein that functionally modulates CaV3 voltage-gated calcium channel activity