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The National Center for Radioecology: A Network of Excellence for Environmental and Human Radiation Risk Reduction (open access)

The National Center for Radioecology: A Network of Excellence for Environmental and Human Radiation Risk Reduction

Radioecology in the United States can be traced back to the early 1950s when small research programs were established to address the fate and effects of radionuclides released in the environment from activities at nuclear facilities. These programs focused primarily on local environmental effects, but global radioactive fallout from nuclear weapons testing and the potential for larger scale local releases of radioisotopes resulted in major concerns about the threat, not only to humans, but to other species and to ecosystems that support all life. These concerns were shared by other countries and it was quickly recognized that a multi-disciplinary approach would be required to address and understand the implications of anthropogenic radioactivity in the environment. The management, clean-up and long-term monitoring of legacy wastes at Department of Energy (DOE), Department of Defense (DOD), and Nuclear Regulatory Commission (NRC)-regulated facilities continues to be of concern as long as nuclear operations continue. Research conducted through radioecology programs provides the credible scientific data needed for decision-making purposes. The current status of radioecology programs in the United States are: fragmented with little coordination to identify national strategies and direct programs; suffering from a steadily decreasing funding base; soon to be hampered by closure of …
Date: January 9, 2013
Creator: Jannik, T.
System: The UNT Digital Library
Diverse values of nature for sustainability (open access)

Diverse values of nature for sustainability

Article describes how, twenty-five years since foundational publications on valuing ecosystems services for human well-being, addressing the global biodiversity crisis still implied confronting barriers to incorporating nature's diverse values into decision-making. The authors assert that a better understanding of how and why nature is (under)valued is more urgent than ever.
Date: August 9, 2023
Creator: Pascual, Unai; Balvanera, Patricia; Anderson, Christopher B.; Chaplin-Kramer, Rebecca; Christie, Michael; González-Jiménez, David et al.
System: The UNT Digital Library
Combined influence of soil moisture and atmospheric humidity on land surface temperature under different climatic background (open access)

Combined influence of soil moisture and atmospheric humidity on land surface temperature under different climatic background

Article describes how soil moisture (SM) and atmospheric humidity (AH) are crucial climatic variables that significantly affect the climate system. However, the combined influencing mechanisms of SM and AH on the land surface temperature (LST) under global warming are still unclear. The authors systematically analyzed the interrelationships among annual mean values of SM, AH, and LST using ERA5-Land reanalysis data and revealed the role of SM and AH on the spatiotemporal variations of LST through mechanism analysis and regression methods.
Date: May 9, 2023
Creator: Jiang, Kang; Pan, Zhihua; Pan, Feifei; Teuling, Adriaan J.; Han, Guolin; An, Pingli et al.
System: The UNT Digital Library
Seeing plants as never before (open access)

Seeing plants as never before

Authors of the article assert that imaging has long supported our ability to understand the inner life of plants, their development, and response to a dynamic environment. The purpose of this review was to provide the scientific community with an overview of current imaging methods, which rely variously on either nuclear magnetic resonance (NMR), mass spectrometry (MS) or infrared (IR) spectroscopy, and to present some examples of their application in order to illustrate their utility.
Date: March 9, 2023
Creator: Borisjuk, Ljudmilla; Horn, Patrick J.; Chapman, Kent Dean; Jakob, Peter M.; Gündel, Andre & Rolletschek, Hardy
System: The UNT Digital Library
Holographic Fabrication of 3D Moiré Photonic Crystals Using Circularly Polarized Laser Beams and a Spatial Light Modulator (open access)

Holographic Fabrication of 3D Moiré Photonic Crystals Using Circularly Polarized Laser Beams and a Spatial Light Modulator

The authors of the article state that holographic fabrication of a 3D moiré photonic crystal is very difficult due to the coexistence of the bright and dark regions, where the exposure threshold is suitable for one region but not for the other. In this paper, the authors study the holographic fabrication of 3D moiré photonic crystals using an integrated system of a single reflective optical element (ROE) and a spatial light modulator (SLM) where nine beams (four inner beams + four outer beams + central beam) are overlapped.
Date: June 9, 2023
Creator: Hurley, Noah; Kamau, Steve; Cui, Jingbiao & Lin, Yuankun
System: The UNT Digital Library
Capabilities, Opportunities, and Motivation: Exploring Fitness Program Experiences of Adults with Intellectual and Developmental Disabilities (open access)

Capabilities, Opportunities, and Motivation: Exploring Fitness Program Experiences of Adults with Intellectual and Developmental Disabilities

Article asserts that, although there are many benefits to regular engagement in physical activity, adults with intellectual and developmental disabilities often do not engage in or near the recommended amount of physical activity. The present study used qualitative methods to explore the experiences of adults with intellectual and developmental disabilities enrolled in a fitness program.
Date: May 9, 2023
Creator: Savage, Melissa N. & Colombo-Dougovito, Andrew M.
System: The UNT Digital Library
Study of B to pi l nu and B to rho l nu Decays and Determination of |V_ub| (open access)

Study of B to pi l nu and B to rho l nu Decays and Determination of |V_ub|

We present an analysis of exclusive charmless semileptonic B-meson decays based on 377 million B{bar B} pairs recorded with the BABAR detector at the {Upsilon} (4S) resonance. We select four event samples corresponding to the decay modes B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}, B{sup +} {yields} {pi}{sup 0}{ell}{sup +}{nu}, B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}, and B{sup +} {yields} {rho}{sup 0}{ell}{sup +}{nu}, and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B {yields} {pi}{ell}{nu} samples, and similarly the two B {yields} {rho}{ell}{nu} samples, and measure the branching fractions {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.41 {+-} 0.05 {+-} 0.07) x 10{sup -4} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{ell}{sup +}{nu}) = (1.75 {+-} 0.15 {+-} 0.27) x 10{sup -4}, where the errors are statistical and systematic. We compare the measured distribution in q{sup 2}, the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the CKM matrix element |V{sub ub}|. Based on the measured partial branching fraction for B {yields} {pi}{ell}{nu} in the range q{sup 2} < 12 GeV{sup 2} and the most recent LCSR calculations we obtain |V{sub ub}| = (3.78 {+-} 0.13{sub -0.40}{sup …
Date: December 9, 2011
Creator: del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
System: The UNT Digital Library
Study of di-pion Bottomonium Transitions and Search for the h_b(1P) State (open access)

Study of di-pion Bottomonium Transitions and Search for the h_b(1P) State

We study inclusive di-pion decays using a sample of 108 x 10{sup 6} {Upsilon}(3S) events recorded with the BABAR detector. We search for the decay mode {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}h{sub b} (1P) and find no evidence for the bottomonium spin-singlet state h{sub b}(1P) in the invariant mass distribution recoiling against the {pi}{sup +}{pi}{sup -} system. Assuming the h{sub b}(1P) mass to be 9.900 GeV/c{sup 2}, we measure the upper limit on the branching fraction {Beta}[{Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}h{sub b}(1P)] < 1.2 x 10{sup -4}, at 90% confidence level. We also investigate the {chi}{sub bJ}(2P) {yields} {pi}{sup +}{pi}{sup -} {chi}{sub bJ}(1P), {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(2S), and {Upsilon}(2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S) di-pion transitions and present an improved measurement of the branching fraction of the {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(2S) decay and of the {Upsilon}(3S) - {Upsilon}(2S) mass difference.
Date: December 9, 2011
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
System: The UNT Digital Library
Rapid Column Extraction Methods for Urine (open access)

Rapid Column Extraction Methods for Urine

A new fecal analysis method that dissolves plutonium oxide was developed at the Westinghouse Savannah River Site. Diphonix Resin (Eichrom Industries), is used to pre-concentrate the actinides from digested fecal samples. A rapid microwave digestion technique is used to remove the actinides from the Diphonix Resin, which effectively extracts plutonium and americium from acidic solutions containing hydrofluoric acid. After resin digestion, the plutonium and americium are recovered in a small volume of nitric acid that is loaded onto small extraction chromatography columns, TEVA Resin and TRU Resin (Eichrom Industries). The method enables complete dissolution of plutonium oxide and provides high recovery of plutonium and americium with good removal of thorium isotopes such as thorium-228.
Date: June 9, 2000
Creator: Maxwell, S. L., III
System: The UNT Digital Library
Effect of Native Defects on Optical Properties of InxGa1-xNAlloys (open access)

Effect of Native Defects on Optical Properties of InxGa1-xNAlloys

The energy position of the optical absorption edge and the free carrier populations in In{sub x}Ga{sub 1-x}N ternary alloys can be controlled using high energy {sup 4}He{sup +} irradiation. The blue shift of the absorption edge after irradiation in In-rich material (x > 0.34) is attributed to the band-filling effect (Burstein-Moss shift) due to the native donors introduced by the irradiation. In Ga-rich material, optical absorption measurements show that the irradiation-introduced native defects are inside the bandgap, where they are incorporated as acceptors. The observed irradiation-produced changes in the optical absorption edge and the carrier populations in In{sub x}Ga{sub 1-x}N are in excellent agreement with the predictions of the amphoteric defect model.
Date: May 9, 2005
Creator: Li, S. X.; Haller, E. E.; Yu, K. M.; Walukiewicz, W.; Ager, J. W., III; Wu, J. et al.
System: The UNT Digital Library
Densities of Sodium Tetrafluoroborate Aqueous Solutions at 20 Degrees C (open access)

Densities of Sodium Tetrafluoroborate Aqueous Solutions at 20 Degrees C

Analytical data and plant solution compositions are often reported in molarity units. Densities of salt solutions are needed to convert the concentrations to molal basis in order to utilize physical property data that have been established on a molal basis, for example, solution reaction equilibrium constants or activity coefficients. We report here the densities at 20.0 Degrees C of sodium tetrafluoroborate (NaBF4) solutions from 0.05 molal to 9.0 molal, near saturation of 9.2 molal.
Date: July 9, 2002
Creator: Crooks, W. J., III
System: The UNT Digital Library
Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/LiOH system (open access)

Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/LiOH system

In this report, we present the use of temperature programmed reaction/decomposition (TPR) in the isoconversion mode to measure outgassing kinetics and to make kinetic prediction concerning hydrogen release from the polycrystalline LiH/LiOH system in the absence of any external H{sub 2}O source.
Date: March 9, 2005
Creator: Dinh, L. N.; Grant, D. M.; Schildbach, M. A.; Smith, R. A.; Leckey, J. H.; Siekhaus, W. J. et al.
System: The UNT Digital Library
Gas Phase Molecular Dynamics (open access)

Gas Phase Molecular Dynamics

The goal of this research is the understanding of elementary chemical and physical processes important in the combustion of fossil fuels. Interest centers on reactions involving short-lived chemical intermediates and their properties. High-resolution, high-sensitivity, laser absorption methods are augmented by high temperature flow-tube reaction kinetics studies with mass-spectrometric sampling. These experiments provide information on the energy levels, structures and reactivity of molecular free radical species and, in turn, provide new tools for the study of energy flow and chemical bond cleavage in the radicals in chemical systems. The experimental work is supported by theoretical and computational work using time-dependent quantum wavepacket calculations that provide insights into energy flow between the vibrational modes of the molecule. The work of group members Fockenberg and Muckerman is described in separate abstracts of this volume.
Date: June 9, 1999
Creator: Sears, T. J.; Hall, G. E.; Preses, J. M. & Weston, R. E., Jr.
System: The UNT Digital Library
Perchlorate and Nitrate Remediation Efficiency and Microbial Diversity in a Containerized Wetland Bioreactor (open access)

Perchlorate and Nitrate Remediation Efficiency and Microbial Diversity in a Containerized Wetland Bioreactor

We have developed a method to remove perchlorate (14 to 27 {micro}g/L) and nitrate (48 mg/L) from contaminated groundwater using a wetland bioreactor. The bioreactor has operated continuously in a remote field location for more than two years with a stable ecosystem of indigenous organisms. This study assesses the bioreactor for long-term perchlorate and nitrate remediation by evaluating influent and effluent groundwater for reduction-oxidation conditions and nitrate and perchlorate concentrations. Total community DNA was extracted and purified from 10-g sediment samples retrieved from vertical coring of the bioreactor during winter. Analysis by denaturing gradient gel electrophoresis of short, 16S rDNA, polymerase-chain-reaction products was used to identify dominant microorganisms. Bacteria genera identified were closely affiliated with bacteria widely distributed in soils, mud layers, and fresh water. Of the 17 dominant bands sequenced, most were gram negative and capable of aerobic or anaerobic respiration with nitrate as the terminal electron acceptor (Pseudomonas, Acinetobacter, Halomonas, and Nitrospira). Several identified genera (Rhizobium, Acinetobactor, and Xanthomonas) are capable of fixing atmospheric nitrogen into a combined form (ammonia) usable by host plants. Isolates were identified from the Proteobacteria class, known for the ability to reduce perchlorate. Initial bacterial assessments of sediments confirm the prevalence of facultative …
Date: June 9, 2004
Creator: Daily, Bill, Jr.; Dibley, Valerie; Pinkart, Holly & Legler, Tina
System: The UNT Digital Library
Two legume fatty acid amide hydrolase isoforms with distinct preferences for microbial- and plant-derived acylamides (open access)

Two legume fatty acid amide hydrolase isoforms with distinct preferences for microbial- and plant-derived acylamides

Article describes how analysis of FAAHs from multiple angiosperm species, which revealed two conserved phylogenetic groups that differed in key conserved residues in the substrate binding pocket. The authors combined computational and biochemical approaches to compare the structural and enzymatic properties of two FAAH isoforms in the legume Medicago truncatula designated MtFAAH1 MtFAAH2a.
Date: May 9, 2023
Creator: Arias-Gaguancela, Omar; Herrell, Emily; Aziz, Mina & Chapman, Kent Dean
System: The UNT Digital Library
Phrasal Proper Names in German and Norwegian (open access)

Phrasal Proper Names in German and Norwegian

Article discusses the morpho-syntax of phrasal proper names like Deutsche Bahn 'German Railway' and Norske Skog 'Norwegian Forest' in German and Norwegian. The authors document that phrasal proper names may show features of recursivity evidenced most clearly in Norwegian.
Date: September 9, 2023
Creator: Julien, Marit & Roehrs, Dorian
System: The UNT Digital Library