Physical Sciences and Mathematics Commons^™

Estimated Probability Of Becoming A Case Of Drug Dependence In Relation To Duration Of Drug-Taking Experience: A Function Approach, Olga A. Vsevolozhskaya, James C. Anthony

Olga A. Vsevolozhskaya

Measured as elapsed time from first use to dependence syndrome onset, the estimated 'induction interval' for cocaine clearly is short relative to the cannabis interval, but little is known about risk of becoming dependent when use persists. Published estimates for this facet of drug dependence epidemiology are from life histories elicited years after first use. To improve estimation, we turn to new data from nationally representative samples of newly incident drug users identified via probability sampling and confidential computer-assisted self-interviews for the National Surveys on Drug Use and Health, 2004-2013. Standardized modules assess first and most recent use, and dependence …

The Neutron Time-Of-Flight Cross Section Program At The University Of Kentucky - Adventures In Analysis Ii, J. R. Vanhoy, S. F. Hicks, B. C. Combs, B. P. Crider, A. J. French, E. A. Garza, S. L. Henderson, T. J. Howard, S. H. Liu, S. Nigam, R. L. Pecha, E. E. Peters, Francisco M. Prados-Estévez, Marcus T. Mcellistrem, B. J. Rice, T. J. Ross, Z. C. Santonil, L. C. Sidwell, J. L. Steves, Steven W. Yates

Chemistry Faculty Publications

Elastic and inelastic neutron differential cross sections are measured at the University of Kentucky Accelerator Laboratory (www.pa.uky.edu/accelerator/) at incident energies in the fast neutron region. The laboratorys facilities and instrumentation will be described and our measurement and analysis procedures outlined. Many corrections are required for neutron scattering experiments and the analysis utilizes information from many other cross section data sets and model calculations. Exploring and understanding the limitations of the foundational information and procedures are important for controlling the accuracy of the cross section results. We are examining the limitations in neutron detection efficiency, the normalization of (n,n′ …

“No-Spin” States And Low-Lying Structures In 130Xe And 136Xe, T. J. Ross, E. E. Peters, Anagha Chakraborty, B. P. Crider, Ajay Kumar, S. H. Liu, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, J. R. Vanhoy, Steven W. Yates

Chemistry Faculty Publications

Inelastic neutron scattering on solid ¹³⁰XeF₂ and ¹³⁶XeF₂ targets was utilized to populate excited levels in ¹³⁰Xe and ¹³⁶Xe. When calculating nuclear matrix elements vital to the understanding of double-beta decay, it is important to have a clear understanding of the low-lying level structure of both the parent and daughter nucleus. Of particular relevance to double-beta decay searches are the assignments of 0⁺ states. We show here that in the case of ¹³⁰Xe there are several discrepancies in the adopted level structure. We found that one previous 0⁺ candidate level (1590 …

Studies Of 54,56Fe Neutron Scattering Cross Sections, S. F. Hicks, J. R. Vanhoy, A. J. French, S. L. Henderson, T. J. Howard, R. L. Pecha, Z. C. Santonil, B. P. Crider, S. Liu, Marcus T. Mcellistrem, E. E. Peters, Francisco M. Prados-Estévez, T. J. Ross, Steven W. Yates

Chemistry Faculty Publications

Elastic and inelastic neutron scattering differential cross sections and γ-ray production cross sections have been measured on ^54,56Fe at several incident energies in the fast neutron region between 1.5 and 4.7 MeV. All measurements were completed at the University of Kentucky Accelerator Laboratory (UKAL) using a 7-MV Model CN Van de Graaff accelerator, along with the neutron production and neutron and γ-ray detection systems located there. The facilities at UKAL allow the investigation of both elastic and inelastic scattering with nearly mono-energetic incident neutrons. Time-of-flight techniques were used to detect the scattered neutrons for the differential cross section measurements. …

Dipole Strength Distributions From Higs Experiments, V. Werner, N. Cooper, P. M. Goddard, P. Humby, R. S. Ilieva, G. Rusev, J. Beller, C. Bernards, B. P. Crider, J. Isaak, J. H. Kelley, E. Kwan, B. Löher, E. E. Peters, N. Pietralla, C. Romig, D. Savran, M. Scheck, A. P. Tonchev, W. Tornow, Steven W. Yates, M. Zweidinger

Chemistry Faculty Publications

A series of photon scattering experiments has been performed on the double-beta decay partners ⁷⁶Ge and ⁷⁶Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesis

Inelastic Neutron Scattering Studies Of 76Ge And 76Se: Relevance To Elevance To Neutrinoless Double-Β Decay, B. P. Crider, E. E. Peters, T. J. Ross, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, J. M. Allmond, J. R. Vanhoy, Steven W. Yates

Chemistry Faculty Publications

Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched ⁷⁶Ge and ⁷⁶Se scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, γ-ray cross sections for the ⁷⁶Ge(n,n′γ) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of γ rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double β …

Descant And Β-Delayed Neutron Measurements At Triumf, V. Bildstein, P. E. Garrett, S. F. Ashley, G. C. Ball, L. Bianco, D. Bandyopadhyay, J. Bangay, B. P. Crider, G. Demand, G. Deng, I. Dillman, A. Finlay, A. B. Garnsworthy, G. Hackman, B. Hadinia, R. Krücken, K. G. Leach, J-P. Martin, Marcus T. Mcellistrem, C. J. Pearson, E. E. Peters, Francisco M. Prados-Estévez, A. Radich, F. Sarazin, C. Sumithrarachchi, C. E. Svensson, J. R. Vanhoy, J. Wong, Steven W. Yates

Chemistry Faculty Publications

The DESCANT array (Deuterated Scintillator Array for Neutron Tagging) consists of up to 70 detectors, each filled with approximately 2 liters of deuterated benzene. This scintillator material o_ers pulse-shape discrimination (PSD) capabilities to distinguish between neutrons and γ-rays interacting with the scintillator material. In addition, the anisotropic nature of n – d scattering allows for the determination of the neutron energy spectrum directly from the pulse height spectrum, complementing the traditional time-of-flight (ToF) information. DESCANT can be coupled either to the TIGRESS (TRIUMF-ISAC Gamma-Ray Escape …

Inelastic Neutron Scattering Studies Of 132,134Xe: Elucidating Structure In A Transitional Region And Possible Interferences For 0vββ Searches, E. E. Peters, T. J. Ross, B. P. Crider, S. F. Ashley, Anagha Chakraborty, M. D. Hennek, Ajay Kumar, S. H. Liu, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, J. S. Thrasher, Steven W. Yates

Chemistry Faculty Publications

Highly enriched (> 99.9%) ¹³²Xe and ¹³⁴Xe gases were converted to solid ¹³²XeF₂ and ¹³⁴XeF₂ and were used as scattering samples for inelastic neutron scattering measurements at the University of Kentucky Accelerator Laboratory (UKAL). Lifetimes of levels up to 3.5MeV in excitation energy in these xenon isotopes were measured using the Doppler-shift attenuation method, allowing the determination of reduced transition probabilities. Gamma rays corresponding to new transitions and levels have been observed. In particular, tentative new excited 0⁺ states and associated decays have been examined in an effort to elucidate the structure of …

Crystal Growth And Electronic Phase Diagram Of 4D-Doped Na1-ΔFe1-XRhXAs In Comparison To 3D-Doped Na1-ΔFe1-XCoXAs, Frank Steckel, Maria Roslova, Robert Beck, Igor Morozov, Saicharan Aswartham, Daniil Evtushinsky, Christian G. F. Blum, Mahmoud Abdel-Hafiez, Dirk Bombor, Janek Maletz, Sergey Borisenko, Andrei V. Shevelkov, Anja U. B. Wolter, Christian Hess, Sabine Wurmehl, Bernd Büchner

Physics and Astronomy Faculty Publications

Single crystals of Na_1−δFe_1−xT_xAs with T = Co, Rh have been grown using a self-flux technique. The crystals were thoroughly characterized by powder x-ray diffraction, magnetic susceptibility, and electronic transport with particular focus on the Rh-doped samples. Measurements of the specific heat and ARPES were conducted exemplarily for the optimally doped compositions. The spin-density wave transition (SDW) observed for samples with low Rh concentration (0≤x≤0.013) is fully suppressed in the optimally doped sample. The superconducting transition temperature (T_c) is enhanced from 10 K in Na_1−δFeAs to 21 …

Metal-Poor, Strongly Star-Forming Galaxies In The Deep2 Survey: The Relationship Between Stellar Mass, Temperature-Based Metallicity, And Star Formation Rate, Chun Ly, Jane R. Rigby, Michael Cooper, Renbin Yan

Physics and Astronomy Faculty Publications

We report on the discovery of 28 z ≈ 0.8 metal-poor galaxies in DEEP2.

For the remainder of the abstract, please download this article or visit https://doi.org/10.1088/0004-637X/805/1/45.

Isolation Of Flow And Nonflow Correlations By Two- And Four-Particle Cumulant Measurements Of Azimuthal Harmonics In √SNn=200 Gev Au+Au Collisions, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, N. M. Abdelwahab, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin

Physics and Astronomy Faculty Publications

A data-driven method was applied to Au+Au collisions at √sNN = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δη-dependent and Δη-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a Δη-independent component of the correlation, which is dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity |η| < 1. In 20–30% central Au+Au colli- sions, the relative flow fluctuation was found to be 34% ± 2%(stat.) ± 3%(sys.) for particles with transverse momentum P_T less than 2 GeV/c. The Δη-dependent part, attributed to nonflow correlations, is found to be 5% ± 2%(sys.) relative to the flow …

High-Energy Electronic Excitations In Sr2Iro4 Observed By Raman Scattering, Jhih-An Yang, Yi-Ping Huang, Michael Hermele, Tongfei Qi, Gang Cao, Dmitry Reznik

Physics and Astronomy Faculty Publications

Spin-orbit interaction in Sr₂IrO₄ leads to the realization of the J_eff=1/2 state and also induces an insulating behavior. Using large-shift Raman spectroscopy, we found two high-energy excitations of the d-shell multiplet at 690 and 680 meV with A_1g and B_1g symmetry, respectively. As temperature decreases, the A_1g and B_1g peaks narrow, and the A_1g peak shifts to higher energy while the energy of the B_1g peak remains the same. When 25% of Ir is substituted with Rh the A_1g peak softens by 10% but the B …

Accurate Determination Of The Free–Free Gaunt Factor – Ii. Relativistic Gaunt Factors, P. A. M. Van Hoof, Gary J. Ferland, R. J. R. Williams, K. Volk, Marios Chatzikos, M. Lykins, R. L. Porter

Physics and Astronomy Faculty Publications

When modelling an ionized plasma, all spectral synthesis codes need the thermally averaged free–free Gaunt factor defined over a very wide range of parameter space in order to produce an accurate prediction for the spectrum. Until now no data set exists that would meet these needs completely. We have therefore produced a table of relativistic Gaunt factors over a much wider range of parameter space than has ever been produced before. We present tables of the thermally averaged Gaunt factor covering the range ¹⁰log γ² = −6 to 10 and ¹⁰log u = −16 to 13 for …

Precision Measurements Of AN1 In The Deep Inelastic Regime, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, D. S. Parno, D. Flay, M. Posik, W. Armstrong, T. Averett, F. Benmokhtar, W. Bertozzi, A. Camsonne, M. Canan, G. D. Cates

Physics and Astronomy Faculty Publications

We have performed precision measurements of the double-spin virtual-photon asymmetry A₁ on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer and a longitudinally and transversely polarized ³He target. Our data cover a wide kinematic range 0.277 ≤ x ≤ 0.548 at an average Q² value of 3.078 (GeV/c)², doubling the available high-precision neutron data in this x range. We have combined our results with world data on proton targets to make a leading-order extraction of the ratio of polarized-to-unpolarized parton distribution functions for up quarks and for down quarks in …

P-Manga: Gradients In Recent Star Formation Histories As Diagnostics For Galaxy Growth And Death, Cheng Li, Enci Wang, Lin Lin, Matthew A. Bershady, Kevin Bundy, Christy A. Tremonti, Ting Xiao, Renbin Yan, Dmitry Bizyaev, Michael Blanton, Sabrina Cales, Brian Cherinka, Edmond Cheung, Niv Drory, Eric Emsellem, Hai Fu, Joseph Gelfand, David R. Law, Lahwai Lin, Nick Macdonald, Claudia Maraston, Karen L. Masters, Michael R. Merrifield, Kaike Pan, S. F. Sánchez, Donald P. Schneider, Daniel Thomas, David Wake, Lixin Wang, Anne-Marie Weijmans, David Wilkinson, Peter Yoachim, Kai Zhang, Tiantian Zheng

Physics and Astronomy Faculty Publications

We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Å break (D_n(4000)), Hδ absorption (EW(Hδ_A)), and Hα emission (EW(Hα)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether D_n(4000) measured in the central spaxel of each datacube exceeds 1.6. For …

Assessing The Probability That A Finding Is Genuine For Large-Scale Genetic Association Studies, Chia-Ling Kuo, Olga A. Vsevolozhskaya, Dmitri V. Zaykin

Olga A. Vsevolozhskaya

Genetic association studies routinely involve massive numbers of statistical tests accompanied by P-values. Whole genome sequencing technologies increased the potential number of tested variants to tens of millions. The more tests are performed, the smaller P-value is required to be deemed significant. However, a small P-value is not equivalent to small chances of a spurious finding and significance thresholds may fail to serve as efficient filters against false results. While the Bayesian approach can provide a direct assessment of the probability that a finding is spurious, its adoption in association studies has been slow, due in part to the ubiquity …

A Wfc3 Grism Emission Line Redshift Catalog In The Goods-South Field, Aaron M. Morris, Dale D. Kocevski, Jonathan R. Trump, Benjamin J. Weiner, Nimish P. Hathi, Guillermo Barro, Tomas Dahlen, Sandra M. Faber, Steven L. Finkelstein, Adriano Fontana, Henry C. Ferguson, Norman A. Grogin, Ruth Grützbauch, Yicheng Guo, Li-Ting Hsu, Anton M. Koekemoer, David C. Koo, Bahram Mobasher, Janine Pforr, Mara Salvato, Tommy Wiklind, Stijn Wuyts

Physics and Astronomy Faculty Publications

We combine Hubble Space Telescope (HST)/Wide Field Camera3 (WFC3) imaging and G141 grism observations from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and 3D-HST surveys to produce a catalog of grism spectroscopic redshifts for galaxies in the CANDELS/GOODS-South field. The WFC3/G141 grism spectra cover a wavelength range of 1.1 ≼ λ ≼ 1.7 μm with a resolving power of R ~ 130 for point sources, thus providing rest-frame optical spectra for galaxies out to z ~ 3.5. The catalog is selected in the H-band (F160W) and includes both galaxies with and without previously …

Bootstrapping Dielectronic Recombination From Second-Row Elements And The Orion Nebula, N. R. Badnell, Gary J. Ferland, T. W. Gorczyca, D. Nikolić, Gururaj Anil Wagle

Physics and Astronomy Faculty Publications

Dielectronic recombination (DR) is the dominant recombination process for most heavy elements in photoionized clouds. Accurate DR rates for a species can be predicted when the positions of autoionizing states are known. Unfortunately such data are not available for most third- and higher-row elements. This introduces an uncertainty that is especially acute for photoionized clouds, where the low temperatures mean that DR occurs energetically through very low-lying autoionizing states. This paper discusses S²⁺ → S⁺ DR, the process that is largely responsible for establishing the [S iii]/[S ii] ratio in nebulae. We derive an empirical rate coefficient using …

Atomic Data For Zn Ɪɪ: Improving Spectral Diagnostics Of Chemical Evolution In High-Redshift Galaxies, Romas Kisielius, Varsha P. Kulkarni, Gary J. Ferland, Pavel Bogdanovich, Debopam Som, Matt L. Lykins

Physics and Astronomy Faculty Publications

Damped Lyα (DLA) and sub-DLA absorbers in quasar spectra provide the most sensitive tools for measuring the element abundances of distant galaxies. The estimation of abundances from absorption lines depends sensitively on the accuracy of the atomic data used. We have started a project to produce new atomic spectroscopic parameters for optical and UV spectral lines using state-of-the-art computer codes employing a very broad configuration interaction (CI) basis. Here we report our results for Zn ii, an ion used widely in studies of the interstellar medium (ISM) as well as DLAs and sub-DLAs. We report new calculations of many …

Bh2 Revisited: New, Extensive Measurements Of Laser-Induced Fluorescence Transitions And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Fumie X. Sunahori, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni

Chemistry Faculty Publications

The spectroscopy of gas phase BH₂ has not been explored experimentally since the pioneering study of Herzberg and Johns in 1967. In the present work, laser-induced fluorescence (LIF) spectra of the òB₁(Πu)-X̃²A₁ band system of ¹¹BH₂, ¹⁰BH₂, ¹¹BD₂, and ¹⁰BD₂ have been observed for the first time. The free radicals were "synthesized" by an electric discharge through a precursor mixture of 0.5% diborane (B₂H₆ or B₂D₆) in high pressure argon at the exit of …

P-Manga: Full Spectral Fitting And Stellar Population Maps From Prototype Observations, David M. Wilkinson, Claudia Maraston, Daniel Thomas, Lodovico Coccato, Rita Tojeiro, Michele Cappellari, Francesco Belfiore, Matthew Bershady, Mike Blanton, Kevin Bundy, Sabrina Cales, Brian Cherinka, Niv Drory, Eric Emsellem, Hai Fu, David Law, Cheng Li, Roberto Maiolino, Karen Masters, Christy Tremonti, David Wake, Enci Wang, Anne-Marie Weijmans, Ting Xiao, Renbin Yan, Kai Zhang, Dmitry Bizyaev, Jonathan Brinkmann, Karen Kinemuchi, Daniel Oravetz, Kaike Pan, Audrey Simmons

Physics and Astronomy Faculty Publications

MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is a 6-yr SDSS-IV (Sloan Digital Sky Survey IV) survey that will obtain resolved spectroscopy from 3600 to 10 300 Å for a representative sample of over 10 000 nearby galaxies. In this paper, we derive spatially resolved stellar population properties and radial gradients by performing full spectral fitting of observed galaxy spectra from P-MaNGA, a prototype of the MaNGA instrument. These data include spectra for 18 galaxies, covering a large range of morphological type. We derive age, metallicity, dust, and stellar mass maps, and their radial gradients, using high spectral-resolution stellar …

P-Manga Galaxies: Emission-Lines Properties – Gas Ionization And Chemical Abundances From Prototype Observations, F. Belfiore, R. Maiolino, K. Bundy, D. Thomas, C. Maraston, D. Wilkinson, S. F. Sánchez, M. Bershady, G. A. Blanc, M. Bothwell, S. L. Cales, L. Coccato, N. Drory, E. Emsellem, H. Fu, J. Gelfand, D. Law, K. Masters, J. Parejko, C. Tremonti, D. Wake, A. Weijmans, Renbin Yan, T. Xiao, K. Zhang, T. Zheng, K. Bizyaev, K. Kinemuchi, D. Oravetz, A. Simmons

Physics and Astronomy Faculty Publications

MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is a 6-yr Sloan Digital Sky Survey (SDSS-IV) survey that will obtain spatially resolved spectroscopy from 3600 to 10 300 Å for a representative sample of over 10 000 nearby galaxies. In this paper, we present the analysis of nebular emission-line properties using observations of 14 galaxies obtained with P-MaNGA, a prototype of the MaNGA instrument. By using spatially resolved diagnostic diagrams, we find extended star formation in galaxies that are centrally dominated by Seyfert/LINER-like emission, which illustrates that galaxy characterizations based on single fibre spectra are necessarily incomplete. We observe extended …

A Slow Neutron Polarimeter For The Measurement Of Parity-Odd Neutron Rotary Power, W. M. Snow, E. Anderson, L. Barrón-Palos, C. D. Bass, T. D. Bass, B. E. Crawford, Christopher Crawford, J. M. Dawkins, D. Esposito, J. Fry, H. Gardiner, K. Gan, C. Haddock, B. R. Heckel, A. T. Holley, J. C. Horton, C. Huffer, J. Lieffers, D. Luo, M. Maldonado-Velázquez, D. M. Markoff, A. M. Micherdzinska, H. P. Mumm, J. S. Nico, M. Sarsour, S. Santra, E. I. Sharapov, H. E. Swanson, S. B. Walbridge, V. Zhumabekova

Physics and Astronomy Faculty Publications

We present the design, description, calibration procedure, and an analysis of systematic effects for an apparatus designed to measure the rotation of the plane of polarization of a transversely polarized slow neutron beam as it passes through unpolarized matter. This device is the neutron optical equivalent of a crossed polarizer/analyzer pair familiar from light optics. This apparatus has been used to search for parity violation in the interaction of polarized slow neutrons in matter. Given the brightness of existing slow neutron sources, this apparatus is capable of measuring a neutron rotary power of dϕ/dz = 1 × 10⁻⁷ rad/m.

Phenomenology Of N-N̄ Oscillations Revisited, Susan Gardner, Ehsan Jafari

Physics and Astronomy Faculty Publications

We revisit the phenomenology of n−n̄ oscillations in the presence of external magnetic fields, highlighting the role of spin. We show, contrary to long-held belief, that the n−n̄ transition rate need not be suppressed, opening new opportunities for its empirical study.

Measurement Of The Scattering Cross Section Of Slow Neutrons On Liquid Parahydrogen From Neutron Transmission, K. B. Grammer, R. Alarcon, L. Barrón-Palos, D. Blyth, J. D. Bowman, J. Calarco, Christopher Crawford, K. Craycroft, D. Evans, N. Fomin, J. Fry, M. Gericke, R. C. Gillis, G. L. Greene, J. Hamblen, C. Hayes, S. Kucuker, R. Mahurin, M. Maldonado-Velázquez, E. Martin, M. Mccrea, P. E. Mueller, M. Musgrave, H. Nann, S. I. Penttilä, W. M. Snow, Z. Tang, W. S. Wilburn

Physics and Astronomy Faculty Publications

Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many-body physics. . . .

The remainder of this abstract can be read at:

http://dx.doi.org/10.1103/PhysRevB.91.180301

Measurement Of The Formation Rate Of Muonic Hydrogen Molecules, V. A. Andreev, T. I. Banks, R. M. Carey, T. A. Case, S. M. Clayton, K. M. Crowe, J. Deutsch, J. Egger, S. J. Freedman, V. A. Ganzha, Tim Gorringe, F. E. Gray, D. W. Hertzog, M. Hildebrandt, P. Kammel, B. Kiburg, S. Knaack, P. A. Kravtsov, A. G. Krivshich, B. Lauss, K. R. Lynch, E. M. Maev, O. E. Maev, F. Mulhauser, C. Petitjean, G. E. Petrov, R. Prieels, G. N. Schapkin, G. G. Semenchuk, M. A. Soroka, Vladimir Tishchenko, A. A. Vasilyev, A. A. Vorobyov, M. E. Vznuzdaev, P. Winter

Physics and Astronomy Faculty Publications

Background: The rate λ_ppμ characterizes the formation of ppμ molecules in collisions of muonic pμ atoms with hydrogen. In measurements of the basic weak muon capture reaction on the proton to determine the pseudoscalar coupling g_P, capture occurs from both atomic and molecular states. Thus knowledge of λ_ppμ is required for a correct interpretation of these experiments.

Purpose: Recently the MuCap experiment has measured the capture rate Λ_S from the singlet pμ atom, employing a low-density active target to suppress ppμ formation [V. Andreev et al. (MuCap Collaboration), Phys. Rev. Lett. 110, 012504 (2013) …

Collectivity Of 0+ States In 160Gd, S. R. Lesher, C. Casarella, A. Aprahamian, B. P. Crider, R. Ikeyama, I. R. Marsh, Marcus T. Mcellistrem, Erin E. Peters, F. M. Prados-Estévez, M. K. Smith, Z. R. Tully, J. R. Vanhoy, Steven W. Yates

Chemistry Faculty Publications

Excited 0⁺ states in ¹⁶⁰Gd have been examined with the (n,n′γ) reaction at incident neutron energies up to 2.8 MeV. Gamma-ray excitation functions and angular distribution measurements allow the confirmation of the existence of 0⁺ states at 1379.70 keV and 1558.30 keV, but we reject the assignments of additional previously suggested 0⁺ candidates. Limits on the level lifetimes of the observed 0⁺ states permit an evaluation of the collectivity of these states.

Practicing Good Stewardship When Applying Herbicides For Pasture Weed Control, Jonathan D. Green

Agriculture and Natural Resources Publications

Various methods and strategies can be used to combat weed problems in pasture fields. These include mechanical and cultural practices such as mowing or clipping fields, maintaining a good soil fertility program, grazing methods, and other management practices that promote the growth of desirable forage grasses which in turn compete against weeds. Herbicides can be the best alternative to effectively control several troublesome broadleaf weeds. However, it is important to understand the proper use of herbicides and practice good stewardship. Below are some important tips to consider when choosing and applying a herbicide product.

Aquatic Macroinvertebrates: Biological Indicators Of Stream Health, Carmen T. Agouridis, Evan T. Wesley, Tyler M. Sanderson, Blake L. Newton

Agriculture and Natural Resources Publications

Streams are an important part of the landscape. Streams transport water, sediment and energy; provide habitat for aquatic life and support terrestrial life; provide a place for recreation; and in many cases serve as a water supply. The health of streams—or their ability to perform these important functions—is dependent on the conditions of the watersheds which they drain. Changes in land use within a watershed can affect a stream’s health (Figure 1).

The Role Of Bulge Formation In The Homogenization Of Stellar Populations At Z ~ 2 As Revealed By Internal Color Dispersion In Candels, Steven Boada, V. Tilvi, R. F. Quadri, M. Hilton, S. Finkelstein, Yicheng Guo, N. Bond, C. Conselice, A. Dekel, H. Ferguson, M. Giavalisco, N. A. Grogin, Dale D. Kocevski, A. M. Koekemoer, D. C. Koo

Physics and Astronomy Faculty Publications

We use data from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey to study how the spatial variation in the stellar populations of galaxies relates to the formation of galaxies at 1.5 < z < 3.5. We use the internal color dispersion (ICD), measured between the rest-frame UV and optical bands, which is sensitive to age (and dust attenuation) variations in stellar populations. The ICD shows a relation with the stellar masses and morphologies of the galaxies. Galaxies with the largest variation in their stellar populations as evidenced by high ICD have disk-dominated morphologies (with Sérsic indexes M/M_⊙) < 11. There is a marked decrease in the ICD as the stellar mass and/or the Sérsic index increases. By studying the relations between the ICD and other galaxy properties including size, total color, star formation rate, and dust attenuation, we conclude that the largest variations in stellar populations occur in galaxies where the light from newly, high star-forming clumps contrasts older stellar disk populations. This phase reaches a peak for galaxies only with a specific stellar mass range, 10 < log(M/M_⊙) < 11, and prior to the formation of a substantial bulge/spheroid. In contrast, galaxies at higher or lower stellar masses and/or higher Sérsic index (n > 2) show reduced ICD values, implying a greater homogeneity of their stellar populations. This indicates that if a galaxy is to have a quiescent bulge along with a star-forming disk, typical of Hubble sequence galaxies, this is most common for stellar masses 10 < log(M/M_⊙) < 11 and when the bulge component remains relatively small (n > 2).