Spatial Relation of Stem Hydroids to Branch Hydroids in Four Pleurocarpous Mosses

The anatomy of branch and main stem connections, with respect to the spatial relation of central strands, was studied in four species of pleurocarpous mosses: Climacium americanum, Climacium dendroides, Rhytidiadelphus triquetrus, and Rhytidium rugosum. In each of these species the central strand consisted entirely of hydroids. Fresh specimens obtained in Iowa and Wisconsin were fixed in CRAF III. To soften tough cell walls, samples were soaked in concentrated (50% aqueous) hydrofluoric acid for one week prior to dehydration in ethyl alcohol. Paraffin (61°c mp) was used as the embedding medium. In the several branch connections studied for each species there was no direct connection between stem and branch central strands

The Bright Ages Survey. II. Evolution of Luminosity, Dust Extinction, and Star Formation from z = 0.5 to z = 2.5

The Bright Ages Survey is a K-band-selected redshift survey over six separate fields with UBVRIzJHK imaging covering a total of 75.6 arcmin(2) and reaching K = 20-20.5. Two fields have deep HST imaging, while all are centered on possible overdensities in the z similar to 2 range. Here we report photometric redshifts and spectroscopy for this sample, which has been described in Paper I. We find 18 galaxies with spectroscopic redshifts of z > 1:5. The derived rest-frame R-band luminosity functions show strong evolution out to z = 2. The luminosity function at z = 2 shows more bright galaxies than at any other epoch, even the extrapolated z = 3 luminosity function from Shapley et al. However, the R-band integrated luminosity density remains roughly constant from to z = 0:5 to z = 2. Evolved galaxies (E, S0, Sa) show a decreasing contribution to the total R-band luminosity density with redshift. The dust extinction in our K-selected sample is moderately larger [median z = 2 E(B - V) 0:30] than that found in Lyman break galaxies, although not enough to make a significant impact on the total light or star formation found at high redshift. We measure the extinction-corrected star formation rate density at z 2, finding ρ_(SFR)(z = 1.5-2.5)= 0.093 M_⊙ yr^(-1) Mpc^(-3), consistent with a relatively flat instantaneous star formation rate from z = 1-4

The Theory of Evolution is Not an Explanation for the Origin of Life

The propagation of misconceptions about the theory of biological evolution must be addressed whenever and wherever they are encountered. The recent article by Paz-y-Mino and Espinoza in this journal contained several such misconceptions, including: that biological evolution explains the origin of life, confusion between biological and cosmological evolution, and the use of the term “Darwinism,” all of which we address here. We argue that science educators, and biology educators particularly, must be aware of these (and other) misconceptions and work to remove them from their classrooms

Ultraviolet-Bright, High-Redshift ULIRGS

We present Spitzer Space Telescope observations of the z=2.38 lya-emitter over-density associated with galaxy cluster J2143-4423, the largest known structure (110 Mpc) above z=2. We imaged 22 of the 37 known lya-emitters within the filament-like structure, using the MIPS 24um band. We detected 6 of the lya-emitters, including 3 of the 4 clouds of extended (>50 kpc) lyman alpha emission, also known as Lya Blobs. Conversion from rest-wavelength 7um to total far-infrared luminosity using locally derived correlations suggests all the detected sources are in the class of ULIRGs, with some reaching Hyper-LIRG energies. Lya blobs frequently show evidence for interaction, either in HST imaging, or the proximity of multiple MIPS sources within the Lya cloud. This connection suggests that interaction or even mergers may be related to the production of Lya blobs. A connection to mergers does not in itself help explain the origin of the Lya blobs, as most of the suggested mechanisms for creating Lya blobs (starbursts, AGN, cooling flows) could also be associated with galaxy interactions.Comment: 12 pages, 3 figures, accepted by ApJ Letter