Physical Sciences and Mathematics Commons^™

Merged Ionization/Dissociation Fronts In Planetary Nebulae, William J. Henney, R. J. R. Williams, Gary J. Ferland, Gargi Shaw, C. R. O'Dell

Physics and Astronomy Faculty Publications

The hydrogen ionization and dissociation front around an ultraviolet radiation source should merge when the ratio of ionizing photon flux to gas density is sufficiently low and the spectrum is sufficiently hard. This regime is particularly relevant to the molecular knots that are commonly found in evolved planetary nebulae, such as the Helix Nebula, where traditional models of photodissociation regions have proved unable to explain the high observed luminosity in H₂ lines. In this paper we present results for the structure and steady state dynamics of such advection-dominated merged fronts, calculated using the Cloudy plasma/molecular physics code. We find …

Spitzer Irs Observations Of Seyfert 1.8 And 1.9 Galaxies: A Comparison With Seyfert 1 And Seyfert 2, R. P. Deo, D. M. Crenshaw, S. B. Kraemer, M. Dietrich, Moshe Elitzur, H. Teplitz, T. J. Turner

Physics and Astronomy Faculty Publications

We present Spitzer mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 μm region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and 2 galaxies from the Spitzer archives. An analysis of the spectral shapes, the silicate 10 μm feature and the emission-line fluxes have enabled us to characterize the mid-IR properties of Seyfert 1.8/1.9s. We find that the EWs of the 10 μm silicate feature are generally weak in all Seyfert galaxies, as previously reported by several studies. The few Seyfert galaxies in this sample that show …

Forage Spokesman Information, Lowell J. Clifford, Barry Drury, John Mcglone, Mac Stone

Kentucky Grazing Conference

No abstract provided.

Techniques For Reducing Mud Problems And Improving Pasture Abused Areas, Ken Johnson

Kentucky Grazing Conference

I would like to approach this topic from two directions, mud control and then problem areas. Mud control in concentrated areas almost impossible with forages alone. Using a mud control product is usually advised. I will talk about several.

My Experiences With Summer Lovegrass, Tim Phillips

Kentucky Grazing Conference

I first heard about teff (Eragrostis tef) being used as a hay crop in early 2006 at a meeting near the Shenandoah Valley area of Virginia. The meeting was about orchardgrass production, so I was speaking about new varieties that are available for producers to grow. Several farmers had experienced massive stand losses of their established orchardgrass hay fields, so they had tried this ‘new’ summer annual grass. Some of the farmers were surprised that I knew about this grass, but I didn’t know about its use as a hay or pasture grass. Teff is the Ethiopian name for a …

Experiences With "Teff" (Summer Love Grass) In Kentucky, Bob Jaynes

Kentucky Grazing Conference

Following publicity about the Klamath Experiment Station evaluation of Teff as an annual forage in 2003 and 2004, requests for more information and seed sources kept KES staff busy for weeks last spring. We received over 300 contacts from 41 states. Local seed salesman Laverne Hankins processed over 150 orders for more than 5 tons of seed. Those who received seed were sent a questionnaire this fall in hopes that we would get feedback on growers experience with this new forage species. To date we have received responses from about 15 growers.

Options For Summer Grazing, David C. Ditsch

Kentucky Grazing Conference

Summer is the time during the growing season when shortages of forage most often occur in Kentucky. The summer of 2007 will long be remembered as one the warmest and driest in recent years and cause many livestock producers to evaluate their current forage systems. Most Kentucky pastures are predominately cool-season grasses such as tall fescue, orchardgrass and bluegrass. During the historically hot, dry periods in July and August, these species produce very little growth and can quickly become overgrazed. At this point, some producers have no alternative except to buy feed or begin feeding stored forage intended for winter …

Surviving The 2007 Drought, Roy Burris

Kentucky Grazing Conference

Kentucky beef producers could feel the effects of the ’07 drought for a long time. Decisions made now will impact the ’08 and ’09 calf crops. The current hay/feed shortage has stimulated a lot of “panic buying”. Feedstuffs with very low nutritive values are being purchased at an alarming rate. These “feeds” are being purchased at much higher costs than we normally pay for good quality hay. If properly supplemented, they can be used successfully. However, their use to replace the normal hay supply could have disastrous results.

Does Grazing Method Matter?, Garry D. Lacefield

Kentucky Grazing Conference

Interest in and opportunities for grazing continues to increase not only in Kentucky, but throughout the U.S. In Wisconsin, 12% or approximately 5000 dairymen are now using grazing. In Michigan, over 40% of the dairymen are using grazing for a significant part of their feed requirements. Over 15% of these dairymen are using intensive grazing. Similar numbers exist for Pennsylvania.

Recovering From The "Freeze" And "Drought" Of 2007, S. Ray Smith

Kentucky Grazing Conference

As all of you know, 2007 has been a devastating year for forage agriculture in Kentucky. The season started with an abnormally warm 7 weeks during late winter and early spring, which promoted lush vegetative growth. Normally this would have been a “good thing”, but it actually made forage plants more vulnerable to below freezing temperatures. Then the severe freeze occurred, with April 7, 8, and 9 the coldest 3 day period in April in KY history. Pastures were stunted for weeks and first cut hay yields were reduced by 35 to 100%. At this point we were still hopeful …

Foreword And Kfgc Award Winners [2007], Garry D. Lacefield, Christi L. Forsythe

Kentucky Grazing Conference

No abstract provided.

A Simple Array Platform For Microrna Analysis And Its Application In Mouse Tissues, Xiaoqing Tang, Jozsef Gal, Xun Zhuang, Wang-Xia Wang, Haining Zhu, Guiliang Tang

Plant and Soil Sciences Faculty Publications

MicroRNAs (miRNAs) are a novel class of small noncoding RNAs that regulate gene expression at the post-transcriptional level and play a critical role in many important biological processes. Most miRNAs are conserved between humans and mice, which makes it possible to analyze their expressions with a set of selected array probes. Here, we report a simple array platform that can detect 553 nonredundant miRNAs encompassing the entire set of miRNAs for humans and mice. The platform features carefully selected and designed probes with optimized hybridization parameters. Potential cross-reaction between mature miRNAs and their precursors was investigated. The array platform was …

The Agn-Obscuring Torus: The End Of The "Doughnut" Paradigm?, Moshe Elitzur, Isaac Shlosman

Physics and Astronomy Faculty Publications

Unified schemes of active galactic nuclei (AGNs) require an obscuring dusty torus around the central engine. The compact sizes (only a few parsecs) determined in recent high-resolution observations require that the obscuring matter be clumpy and located inside the region where the black hole gravity dominates over the galactic bulge. This location is in line with the scenario depicting the torus as the region of the clumpy wind coming off the accretion disk in which the clouds are dusty and optically thick. We study here the outflow scenario within the framework of hydromagnetic disk winds, incorporating the cloud properties determined …

Revisiting He-Like X-Ray Emission-Line Plasma Diagnostics, R. L. Porter, Gary J. Ferland

Physics and Astronomy Faculty Publications

A complete model of helium-like line and continuum emission has been incorporated into the plasma simulation code Cloudy. All elements between He and Zn are treated, any number of levels can be considered, and radiative and collisional processes are included. This includes photoionization from all levels, line transfer, including continuum pumping and destruction by background opacities, scattering, and collisional processes. The model is calculated self-consistently along with the ionization and thermal structure of the surrounding nebula. The result is a complete line and continuum spectrum of the plasma. Here we focus on the ions of the He I sequence and …

The Mid-Infrared Emission Of M87, Eric S. Perlman, R. E. Mason, Christopher Packham, N. A. Levenson, Moshe Elitzur, Justin J. Schaefer, Masatoshi Imanishi, William B. Sparks, James Radomski

Physics and Astronomy Faculty Publications

We discuss Subaru and Spitzer Space Telescope imaging and spectroscopy of M87 in the mid-infrared (mid-IR) from 5 to 35 μm. These observations allow us to investigate mid-IR emission mechanisms in the core of M87 and to establish that the flaring, variable jet component HST-1 is not a major contributor to the mid-IR flux. The Spitzer data include a high signal-to-noise ratio 15-35 μm spectrum of the knot A/B complex in the jet, which is consistent with synchrotron emission. However, a synchrotron model cannot account for the observed nuclear spectrum, even when contributions from the jet, necessary due …

Optically Thick [O I] And [C Ii] Emission Toward Ngc 6334a, N. P. Abel, A. P. Sarma, Thomas H. Troland, Gary J. Ferland

Physics and Astronomy Faculty Publications

This work focuses on [O I] and [C II] emission toward NGC 6334A, an embedded H⁺ region/PDR only observable at infrared or longer wavelengths. A geometry in which nearly all the emission escapes out the side of the cloud facing the stars, such as Orion, is not applicable to this region. Instead, we find the geometry to be one in which the H⁺ region and associated PDR is embedded in the molecular cloud. Constant-density PDR calculations are presented which predict line intensities as a function of A_V [or N(H)], hydrogen density (n_H), and …

Gemini Mid-Ir Polarimetry Of Ngc 1068: Polarized Structures Around The Nucleus, C. Packham, S. Young, S. Fisher, K. Volk, R. Mason, J. H. Hough, P. F. Roche, Moshe Elitzur, J. Radomski, E. Perlman

Physics and Astronomy Faculty Publications

We present diffraction-limited, 10 μm imaging polarimetry data for the central regions of the archetypal Seyfert active galactic nucleus NGC 1068. The position angle of polarization is consistent with three dominant polarizing mechanisms. We identify three distinct regions of polarization: (1) north of the nucleus, arising from aligned dust in the narrow emission line region, (2) south, east, and west of the nucleus, consistent with dust being channeled toward the central engine, and (3) a central minimum of polarization consistent with a compact (≤22 pc) torus. These observations provide continuity between the geometrically and optically thick torus and the …

An Investigation Into The Effects Of Luminosity On The Mid-Infrared Spectral Energy Distributions Of Radio-Quiet Quasars, S. C. Gallagher, G. T. Richards, M. Lacy, D. C. Hines, Moshe Elitzur, L. J. Storrie-Lombardi

Physics and Astronomy Faculty Publications

We present an analysis of the effects of luminosity on the shape of the mid-infrared spectral energy distributions (SEDs) of 234 radio-quiet quasars originally presented by Richards et al. In quasars without evident dust extinction, the spectrally integrated optical and infrared luminosities are linearly correlated over nearly three decades in luminosity. We find a significant (≳99.99\% confidence) correlation between the 1.8-8.0 μm spectral index and infrared luminosity that indicates an enhancement of the mid-infrared continuum with increasing luminosity. Coupled with strong evidence for spectral curvature in more luminous quasars, we conclude that this trend is likely a manifestation of …

A Photon Dominated Region Code Comparison Study, M. Röllig, Nicholas Paul Abel, T. Bell, F. Bensch, J. Black, Gary J. Ferland, B. Jonkheid, I. Kamp, M. J. Kaufman, J. Le Bourlot, F. Le Petit, R. Meijerink, O. Morata, V. Ossenkopf, E. Roueff, Gargi Shaw, M. Spaans, A. Sternberg, J. Stutzki, W.-F. Thi, E. F. Van Dishoeck, P. A. M. Van Hoof, S. Viti, M. G. Wolfire

Physics and Astronomy Faculty Publications

Aims. We present a comparison between independent computer codes, modeling the physics and chemistry of interstellar photon dominated regions (PDRs). Our goal was to understand the mutual differences in the PDR codes and their effects on the physical and chemical structure of the model clouds, and to converge the output of different codes to a common solution.

Methods. A number of benchmark models have been created, covering low and high gas densities n = 10³,10^5.5 cm^-3 and far ultraviolet intensities χ = 10, 10⁵ in units of the Draine field (FUV: 6 < h_ν < 13.6 eV). The benchmark models were computed in two ways: one set assuming constant temperatures, thus testing the consistency of the chemical network and photo-processes, and a second set determining the temperature self consistently by solving the thermal balance, thus testing the modeling of the heating and cooling mechanisms accounting for the detailed energy balance throughout the clouds.

Results. …

Trans-Excision-Splicing Ribozyme And Methods Of Use, Stephen M. Testa, Michael A. Bell

Chemistry Faculty Patents

A group I intron-derived ribozyme which binds RNA in trans, excises an internal segment from within the RNA, and splices the remaining 5′ and 3′ ends of the RNA back together (the trans-excision-splicing reaction) is disclosed. The excised segment can be as long as 28 nucleotides, or more, and as little as one nucleotide. The ribozymes of the invention are easily modified to alter their sequence specificity. Such ribozymes represent a new and potentially powerful class of generally adaptable genetic therapeutics.

Determination Of The Physical Conditions Of The Knots In The Helix Nebula From Optical And Infrared Observations, C. R. O'Dell, W. J. Henney, Gary J. Ferland

Physics and Astronomy Faculty Publications

We use new Hubble Space Telescope and archived images to clarify the nature of the ubiquitous knots in the Helix Nebula, which are variously estimated to contain a significant to majority fraction of the material ejected by its central star. We employ published far-infrared spectrophotometry and existing 2.12 μm images to establish that the population distribution of the lowest rovibrational states of H2 is close to the distribution of a gas in local thermodynamic equilibrium at 988 ± 119 K. In addition, we present calculations that show that the weakness of the H₂ 0-0 S(7) line is not …

Dust And Pah Emission In The Star-Forming Active Nucleus Of Ngc 1097, R. E. Mason, N. A. Levenson, C. Packham, Moshe Elitzur, J. Radomski, A. O. Petric, G. S. Wright

Physics and Astronomy Faculty Publications

The nucleus of the nearby galaxy NGC 1097 is known to host a young, compact (r < 9 pc) nuclear star cluster, as well as a low-luminosity active galactic nucleus (AGN). It has been suggested both that the nuclear stellar cluster is associated with a dusty torus and that low-luminosity AGNs like NGC 1097 do not have the torus predicted by the unified model of AGNs. To investigate these contradictory possibilities we have acquired Gemini/T-ReCS 11.7 and 18.3 μm images of the central few hundred parsecs of this galaxy at <45 pc angular resolution, in which the nucleus and spectacular, kiloparsec-scale star-forming ring are detected in both bands. The small-scale mid-IR luminosity implies thermal emission from warm dust close to the central engine. Fitting of torus models shows that the observed mid-IR emission cannot be accounted for by dust heated by the central engine. Rather, the principal source heating the dust in this object is the nuclear star cluster itself, suggesting that the detected dust is not the torus of AGN unified schemes (although it is also possible that the dusty starburst itself could provide the obscuration invoked by the unified model). Comparison of Spitzer IRS and Gemini GNIRS spectra shows that, although PAH bands are strong in the immediate circumnuclear region of the galaxy, PAH emission is weak or absent in the central 19 pc. The lack of PAH emission can probably be explained largely by destruction/ionization of PAH molecules by hard photons from the nuclear star cluster. If NGC 1097 is typical, PAH emission bands may not be a useful tool with which …

Subdivision Surface-Based Geometric Modeling System, Fuhua Cheng

Computer Science Faculty Patents

A method for surface modeling of images to produce realistic images or to provide simulations with accurate surface information is provided. More particularly, the present invention relates to a new subdivision depth computation technique and to an improved label-driven adaptive subdivision technique for use in Catmull-Clark subdivision surface modeling systems. The method comprises computing a subdivision depth to determine the number of recursive subdivisions which may be performed on a control mesh to generate a plurality of finer mesh elements while preserving a predetermined error tolerance, and using the computed subdivision depth to construct an adaptively refined mesh that is …

A Magnetically Supported Photodissociation Region In M17, E. W. Pellegrini, J. A. Baldwin, C. L. Brogan, M. M. Hanson, N. P. Abel, Gary J. Ferland, H. B. Nemala, G. Shaw, Thomas H. Troland

Physics and Astronomy Faculty Publications

The southwestern (SW) part of the Galactic H II region M17 contains an obscured ionization front that is most easily seen at infrared and radio wavelengths. It is nearly edge-on, thus offering an excellent opportunity to study the way in which the gas changes from fully ionized to molecular as radiation from the ionizing stars penetrates into the gas. M17 is also one of the very few H II regions for which the magnetic field strength can be measured in the photodissociation region ( PDR) that forms the interface between the ionized and molecular gas. Here we model an observed …

Poster Session, Kentucky Water Resources Research Institute, University Of Kentucky

Kentucky Water Resources Annual Symposium

• Identification of potential bacterial sources and levels, Red Duck Creek, Mayfield, Kentucky, Brooke Vorbeck, Travis Martin, and Mike Kemp, Dept of Industrial and Engineering Technology, Murray State University
• Water-quality trend analysis for streams in Kentucky, A.S. Crain and G.R. Martin, USGS, Louisville
• Preliminary Results of a Fecal Microbe Survey in a Eutrophic Lake, Wilgreen Lake, Madison County, Kentucky, W.S. Borowski and M.S. Albright, Depts of Earth Sciences and Geography, EKU
• Preliminary Physical and Chemical Characteristics of an Eutrophic Lake, Wilgreen Lake, Madison County, Kentucky, E.C. Jolly and W.S. Borowski, Dept of Earth Sciences, EKU
• Lethal and …

Session 2d: Superfund, Kentucky Water Resources Research Institute, University Of Kentucky

Kentucky Water Resources Annual Symposium

• Challenges and Opportunities in Working Directly with Affected Superfund Communities in Kentucky, Lisa Gaetke, Nutrition and Food Science, UK
• Selected Chloro-Organic Detoxifications by Poly-Chelate (polyacrylic acid) and Citrate-Based Fenton Reaction at Neutral pH Environment, YongChao Li, L. G. Bachas, and Dibakar Bhattacharyya, Depts of Chemical & Materials Engineering and Chemisty, UK
• Reductive Degradation of Cholorinated Organics by Membrane-Supported Nonoparticles, Jian Xu and Dibakar Bhattacharyya, Dept of Chemical & Materials Engineering, UK

Session 2c: Education/Outreach, Kentucky Water Resources Research Institute, University Of Kentucky

Kentucky Water Resources Annual Symposium

• 5 Stars, 15 Students, and 5000 Trees, A.A. Gumbert and others, Extension Associate for Environmental and Natural Resource Issues, UK
• The Water Pioneers Water Quality Initiative, Stephanie Jenkins, Doug McLaren, Blake Newton, Amanda Abnee, UK
• Local and State Partnership for MS4 Success in Kentucky – Coordinated Communication, Education and Outreach, C.D. McCormick and Shelby Jett, FMSM Engineers, Louisville and Kentucky Transportation Cabinet
• Illicit Discharge Detection and Elimination: A Challenge for Kentucky’s Stormwater Program Cities, B. Tonning, R. Walker, and J. Arnold, Tetra Tech, Lexington

Session 2b: Goundwater, Kentucky Water Resources Research Institute, University Of Kentucky

Kentucky Water Resources Annual Symposium

• Kentucky Groundwater-Quality Mapping Service, R.S. Fisher and Bart Davidson, KGS
• Kentucky Groundwater-Quality Data Search Engine, Bart Davidson and R.S. Fisher, KGS
• Water Quality in the Karst Terrane of the Sinking Creek Basin, Kentucky 2004-06, Angela S. Crain, USGS, Louisville
• Salt Movement Through the Vadose Zone of a Karst Soil – First Experiences with a Transfer Function Approach, Ole Wendroth and others, Dept Plant and Soil Sciences, UK

Session 2a: Surface Water, Kentucky Water Resources Research Institute, University Of Kentucky

Kentucky Water Resources Annual Symposium

• Development and Application of a New Sediment Fingerprinting Methodology for the Commonwealth of Kentucky, Charles Davis and Jimmy Fox, Dept of Civil Engineering, UK
• Accounting for Construction Stormwater in TMDL Development for Sediment Impaired Streams in Rapidly Growing Residential Areas, Jon Ludwig and John Bekman, Tetra Tech, and David Montali, WVDEP
• Responses of Riparian Plant Diversity to Gradients in Flood Frequency and Severity, Patrick Lawless and Jimmy Fox, Depts of Geography and Civil Engineering, UK

Session 1d: Biology, Kentucky Water Resources Research Institute, University Of Kentucky

Kentucky Water Resources Annual Symposium

• Long-Term Assessments and Seasonal Variations of Polychlorinated Biphenyls (PCBs) in Water, Sediments, Floodplain Soils, and Sentinel Fish Species from Big and Little Bayou Creeks, McCracken County, Kentucky, D.J. Price, Dept of Biology, UK
• Characterization of total dissolved solids (TDS) toxicity to Ceriodaphnia dubia associated with effluent discharges from a meat packaging industry, Agus Sofyan and David Price, Dept of Biology, UK
• Wilson Creek Restoration and the Response in Food Web Function and Fish Community Structure, Wesley Daniel and Jeff Jack, Dept of Biology and Center for Environmental Science, U of L