The Nuclear Ionized Gas in the Radio Galaxy M84 (NGC 4374)

We present optical images of the nucleus of the nearby radio galaxy M84 (NGC 4374 = 3C272.1) obtained with the Wide Field/Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope (HST). Our three images cover the H$\alpha$ + [N II] emission lines as well as the V and I continuum bands. Analysis of these images confirms that the H$\alpha$ + [N II] emission in the central 5'' (410 pc) is elongated along position angle (P.A.) \approx 72\arcdeg, which is roughly parallel to two nuclear dust lanes.Our high-resolution images reveal that the H$\alpha$ + [N II] emission has three components, namely a nuclear gas disk,an `ionization cone', and outer filaments. The nuclear disk of ionized gas has diameter $\approx 1'' = 82$ pc and major axis P.A. \approx 58\arcdeg \pm 6\arcdeg. On an angular scale of 0\farcs5, the major axis of this nuclear gas disk is consistent with that of the dust. However, the minor axis of the gas disk (P.A. \approx 148\arcdeg) is tilted with respect to that of the filamentary H$\alpha$ + [N II] emission at distances > 2'' from the nucleus; the minor axis of this larger scale gas is roughly aligned with the axis of the kpc-scale radio jets (P.A. \approx 170\arcdeg). The ionization cone (whose apex is offset by \approx 0\farcs3 south of the nucleus) extends 2'' from the nucleus along the axis of the southern radio jet. This feature is similar to the ionization cones seen in some Seyfert nuclei, which are also aligned with the radio axes.Comment: 11 pages plus 4 figure

The R-Process Alliance: Chemical Abundances for a Trio of R-Process-Enhanced Stars -- One Strong, One Moderate, One Mild

We present detailed chemical abundances of three new bright (V ~ 11), extremely metal-poor ([Fe/H] ~ -3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25 neutron-capture elements in each of our stars. J1432-4125 is among the most r-process rich r-II stars, with [Eu/Fe]= +1.44+-0.11. J2005-3057 is an r-I star with [Eu/Fe] = +0.94+-0.07. J0858-0809 has [Eu/Fe] = +0.23+-0.05 and exhibits a carbon abundance corrected for evolutionary status of [C/Fe]_corr = +0.76, thus adding to the small number of known carbon-enhanced r-process stars. All three stars show remarkable agreement with the scaled solar r-process pattern for elements above Ba, consistent with enrichment of the birth gas cloud by a neutron star merger. The abundances for Sr, Y, and Zr, however, deviate from the scaled solar pattern. This indicates that more than one distinct r-process site might be responsible for the observed neutron-capture element abundance pattern. Thorium was detected in J1432-4125 and J2005-3057. Age estimates for J1432-4125 and J2005-3057 were adopted from one of two sets of initial production ratios each by assuming the stars are old. This yielded individual ages of 12+-6 Gyr and 10+-6 Gyr, respectively.Comment: 30 pages, includes a long table, 5 figure

Cross-correlation Weak Lensing of SDSS Galaxy Clusters III: Mass-to-light Ratios

We present measurements of the excess mass-to-light ratio measured aroundMaxBCG galaxy clusters observed in the SDSS. This red sequence cluster sample includes objects from small groups with masses ranging from ~5x10^{12} to ~10^{15} M_{sun}/h. Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean \Delta \rho(r) = \rho(r) - \bar{\rho} for clusters in bins of richness and optical luminosity. We also measure the excess luminosity density \Delta l(r) = l(r) - \bar{l} measured in the z=0.25 i-band. For both mass and light, we de-project the profiles to produce 3D mass and light profiles over scales from 25 kpc/ to 22 Mpc/h. From these profiles we calculate the cumulative excess mass M(r) and excess light L(r) as a function of separation from the BCG. On small scales, where \rho(r) >> \bar{\rho}, the integrated mass-to-light profile may be interpreted as the cluster mass-to-light ratio. We find the M/L_{200}, the mass-to-light ratio within r_{200}, scales with cluster mass as a power law with index 0.33+/-0.02. On large scales, where \rho(r) ~ \bar{\rho}, the M/L approaches an asymptotic value independent of cluster richness. For small groups, the mean M/L_{200} is much smaller than the asymptotic value, while for large clusters it is consistent with the asymptotic value. This asymptotic value should be proportional to the mean mass-to-light ratio of the universe . We find /b^2_{ml} = 362+/-54 h (statistical). There is additional uncertainty in the overall calibration at the ~10% level. The parameter b_{ml} is primarily a function of the bias of the L <~ L_* galaxies used as light tracers, and should be of order unity. Multiplying by the luminosity density in the same bandpass we find \Omega_m/b^2_{ml} = 0.02+/-0.03, independent of the Hubble parameter.Comment: Third paper in a series; v2.0 incorporates ApJ referee's suggestion

Evaluating the Effectiveness of Streambank Stabilization Techniques for Reducing Bank Erosion on the Upper Clark Fork River, Western Montana

Lateral channel movement on the upper Clark Fork River of western Montana has resulted in loss of valuable agricultural land and delivery of sediment and mine tailings into the river. In spring 1996, we initiated a study to evaluate the effectiveness of streambank stabilization treatments to reduce the potential for bank erosion. The treatments implemented in this study focus on the use of native riparian vegetation to stabilize banks instead of traditional hard treatments such as rip rap. This study examines the effectiveness of 21 different bank stabilization treatment combinations for reducing bank erosion on a large river system. The treatments incorporate coir (coconut husk) fabric, conifer revetments, log barbs, rock barbs, rock toe stabilization, coir fascines, willow (Salix spp.) and red-osier dogwood (Cornus stolonifera) fascines, willow cuttings, containerized seedlings, mature shrub transplants and rock rip rap. Treatments were installed in fall 1996, spring and summer 1997, and fall 1998 on 24 reaches totaling 1,740 m (5,708 ft) in length. Typical sites are on the actively-eroding, concave side of channel meanders and consist of 5-ft. tall, nearly-vertical banks. 140 permanently-monumented cross sections have been monitored before construction and after the construction for all treatments, after ice events in 1997 and 1998 for treatments established at that time, and after peak flow events in 1997 and 1998. A total of 100 bank surface profiles have been monitored by total station and changes in streambank surface volume have been calculated. Survival rates of various vegetative treatments were also monitored, and costs of construction for each individual treatment were calculated from detailed monitoring of construction activities.The 1996-97 and 1997-1998 bankfull discharge ice event caused little erosion. However, the 1997 flood event, rare in its volume and duration, caused substantial erosion of treatment and control banks. 1997 and 1998 flood-caused erosion rates varied between treatments. First year survival was high for mature transplants (100%), containerized seedlings (90%), and vertically-planted willow cuttings (88%). Second year survival was also high for mature transplants and constainerized seedlings, but survival rates dropped drammatically in the second year for vertical willow stakes. Cost of various treatment implementation ranged widely from a low of $5.58/ft to a high of$82.29/ft

The evolutionary diversification of LSF and Grainyhead transcription factors preceded the radiation of basal animal lineages

<p>Abstract</p> <p>Background</p> <p>The transcription factors of the LSF/Grainyhead (GRH) family are characterized by the possession of a distinctive DNA-binding domain that bears no clear relationship to other known DNA-binding domains, with the possible exception of the p53 core domain. In triploblastic animals, the LSF and GRH subfamilies have diverged extensively with respect to their biological roles, general expression patterns, and mechanism of DNA binding. For example, <it>Grainyhead </it>(GRH) homologs are expressed primarily in the epidermis, and they appear to play an ancient role in maintaining the epidermal barrier. By contrast, LSF homologs are more widely expressed, and they regulate general cellular functions such as cell cycle progression and survival in addition to cell-lineage specific gene expression.</p> <p>Results</p> <p>To illuminate the early evolution of this family and reconstruct the functional divergence of LSF and GRH, we compared homologs from 18 phylogenetically diverse taxa, including four basal animals (<it>Nematostella vectensis</it>, <it>Vallicula multiformis</it>, <it>Trichoplax adhaerens</it>, and <it>Amphimedon queenslandica</it>), a choanoflagellate (<it>Monosiga brevicollis</it>) and several fungi. Phylogenetic and bioinformatic analyses of these sequences indicate that (1) the LSF/GRH gene family originated prior to the animal-fungal divergence, and (2) the functional diversification of the LSF and GRH subfamilies occurred prior to the divergence between sponges and eumetazoans. Aspects of the domain architecture of LSF/GRH proteins are well conserved between fungi, choanoflagellates, and metazoans, though within the Metazoa, the LSF and GRH families are clearly distinct. We failed to identify a convincing LSF/GRH homolog in the sequenced genomes of the algae <it>Volvox carteri </it>and <it>Chlamydomonas reinhardtii </it>or the amoebozoan <it>Dictyostelium purpureum</it>. Interestingly, the ancestral GRH locus has become split into two separate loci in the sea anemone <it>Nematostella</it>, with one locus encoding a DNA binding domain and the other locus encoding the dimerization domain.</p> <p>Conclusions</p> <p>In metazoans, LSF and GRH proteins play a number of roles that are essential to achieving and maintaining multicellularity. It is now clear that this protein family already existed in the unicellular ancestor of animals, choanoflagellates, and fungi. However, the diversification of distinct LSF and GRH subfamilies appears to be a metazoan invention. Given the conserved role of GRH in maintaining epithelial integrity in vertebrates, insects, and nematodes, it is noteworthy that the evolutionary origin of Grh appears roughly coincident with the evolutionary origin of the epithelium.</p

Asteroseismology of the Hyades red giant and planet host epsilon Tauri

Asteroseismic analysis of solar-like stars allows us to determine physical parameters such as stellar mass, with a higher precision compared to most other methods. Even in a well-studied cluster such as the Hyades, the masses of the red giant stars are not well known, and previous mass estimates are based on model calculations (isochrones). The four known red giants in the Hyades are assumed to be clump (core-helium-burning) stars based on their positions in colour-magnitude diagrams, however asteroseismology offers an opportunity to test this assumption. Using asteroseismic techniques combined with other methods, we aim to derive physical parameters and the evolutionary stage for the planet hosting star epsilon Tau, which is one of the four red giants located in the Hyades. We analysed time-series data from both ground and space to perform the asteroseismic analysis. By combining high signal-to-noise (S/N) radial-velocity data from the ground-based SONG network with continuous space-based data from the revised Kepler mission K2, we derive and characterize 27 individual oscillation modes for epsilon Tau, along with global oscillation parameters such as the large frequency separation and the ratio between the amplitude of the oscillations measured in radial velocity and intensity as a function of frequency. The latter has been measured previously for only two stars, the Sun and Procyon. Combining the seismic analysis with interferometric and spectroscopic measurements, we derive physical parameters for epsilon Tau, and discuss its evolutionary status.Comment: 13 pages, 13 figures, 4 tables, accepted for publication in Astronomy & Astrophysic

Past, present, and future roles of long-term experiments in the LTER Network

Author Posting. © American Institute of Biological Sciences, 2012. This article is posted here by permission of American Institute of Biological Sciences for personal use, not for redistribution. The definitive version was published in BioScience 62 (2012): 377-389, doi:10.1525/bio.2012.62.4.9.The US National Science Foundation—funded Long Term Ecological Research (LTER) Network supports a large (around 240) and diverse portfolio of long-term ecological experiments. Collectively, these long-term experiments have (a) provided unique insights into ecological patterns and processes, although such insight often became apparent only after many years of study; (b) influenced management and policy decisions; and (c) evolved into research platforms supporting studies and involving investigators who were not part of the original design. Furthermore, this suite of long-term experiments addresses, at the site level, all of the US National Research Council's Grand Challenges in Environmental Sciences. Despite these contributions, we argue that the scale and scope of global environmental change requires a more-coordinated multisite approach to long-term experiments. Ideally, such an approach would include a network of spatially extensive multifactor experiments, designed in collaboration with ecological modelers that would build on and extend the unique context provided by the LTER Network.2012-10-0

Rapid Display of Radiographic Images

The requirements for the rapid display of radiographic images exceed the capabilities of widely available display, computer and communication technologies. Computed radiography captures data with a resolution of about four megapixels. Large format displays are available that can present over four megapixels. One megapixel displays are practical for use in combination with large format displays and in areas where the viewing task does not require primary diagnosis. This paper describes an electronic radiology system that approximates the highest quality systems, but through the use of several interesting techniques allows the possibility of its widespread installation throughout hospitals. The techniques uses can be grouped under three major systems concepts: a local, high-speed Image Server, one of more physician\u27s workstations each with one or more high-performance Auxiliary Displays specialized to the radiology viewing task, and dedicated, high-speed communication links between the server and the displays. This approach is enhanced by the use of a progressive transmission scheme to decrease the latency for viewing four megapixel images. The system includes an Image Server with storage for over 600 4 megapixel images and high-speed link. A subsampled megapixel image is fetched from disk and transmitted to the display in about one second followed by the full resolution 4 megapixel in about 2.5 seconds. Other system components include a megapixel display with a 6 megapixel display memory space and frame-rate update of image roam, zoom and contrast. Plans for clinical use are presented

ArborZ: Photometric Redshifts Using Boosted Decision Trees

Precision photometric redshifts will be essential for extracting cosmological parameters from the next generation of wide-area imaging surveys. In this paper we introduce a photometric redshift algorithm, ArborZ, based on the machine-learning technique of Boosted Decision Trees. We study the algorithm using galaxies from the Sloan Digital Sky Survey and from mock catalogs intended to simulate both the SDSS and the upcoming Dark Energy Survey. We show that it improves upon the performance of existing algorithms. Moreover, the method naturally leads to the reconstruction of a full probability density function (PDF) for the photometric redshift of each galaxy, not merely a single "best estimate" and error, and also provides a photo-z quality figure-of-merit for each galaxy that can be used to reject outliers. We show that the stacked PDFs yield a more accurate reconstruction of the redshift distribution N(z). We discuss limitations of the current algorithm and ideas for future work.Comment: 10 pages, 13 figures, submitted to Ap