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Articles 2581 - 2610 of 2617

Full-Text Articles in Life Sciences

Esr Study Of Free Radicals In Irradiated Single Crystals Of Potassium Hydroxylamine Disulfonate, B. J. Wilson, Robert W. Holmberg Aug 1976

Esr Study Of Free Radicals In Irradiated Single Crystals Of Potassium Hydroxylamine Disulfonate, B. J. Wilson, Robert W. Holmberg

Faculty Publications

Two free radicals formed when single crystals of potassium hydroxylamine disulfonate are irradiated with gamma rays at 77degrees K were studied by ESR. The ESR spectra result from a predominant center (radical A) exhibiting large 14N and 1H hyperfine splittings and from lesser amounts of Fremy's radical [O-dotN(SO3)2-2]. The g and hyperfine tensors of these radicals have been evaluated and are discussed. Radical A, whose identity remains in doubt, may be regarded as the precursor to Fremy's radical; on warming its lines decay and those of Fremy's radical are formed. Lines from radical A decrease in strength and those of …

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Van Der Waals Interactions Of Carbon Monoxide, Gregory A. Parker, Russell T. Pack Mar 1976

Van Der Waals Interactions Of Carbon Monoxide, Gregory A. Parker, Russell T. Pack

Faculty Publications

Pade approximant methods and experimental frequency dependent polarizabilities are used to calculate reliable van der Waals C6 coefficients for the interaction of CO with He, Ne, Ar, Kr, Xe, H, Li, Na, K, Rb, Cs, H2, N2, O2, CO2, and CO. Error bounds are given for the C6 coefficients and for the CO oscillator strength sums.

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Van Der Waals Interactions Of Ii-State Linear Molecules With Atoms. C6 For No(X 2Π) Interactions, Glen C. Nielson, Gregory A. Parker, Russell T. Pack Mar 1976

Van Der Waals Interactions Of Ii-State Linear Molecules With Atoms. C6 For No(X 2Π) Interactions, Glen C. Nielson, Gregory A. Parker, Russell T. Pack

Faculty Publications

Formulas are derived for the van der Waals Cn coefficients for the interaction of a diatomic molecule in a II electronic state with an S-state atom. Two triatomic states arise from the degenerate IIstate. The average of the two energies has the usual Legendre polynomial (PL) angular dependence, but the difference in energies of the two states is shown to have associated Legendre polynomial (PML with M=2) angular dependence. Procedures for including spin orbit coupling are included, and the extension to interactions of Delta- and Phi-state molecules is discussed. Values of the spherical part of the C6 coefficients for the …

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Comment On ''Inelastic Scattering In Atom-Diatomic Molecule Collisions. I. Rotational Transitions In The Sudden Approximation'', Russell T. Pack Feb 1976

Comment On ''Inelastic Scattering In Atom-Diatomic Molecule Collisions. I. Rotational Transitions In The Sudden Approximation'', Russell T. Pack

Faculty Publications

It is argued that conflicting approximations in a recent paper [J. R. Stallcop, J. Chem. Phys. 61, 5085 (1974)] render the resulting theory invalid.

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Effects Of Six Insecticides On Emergence Of Some Parasites And Predators From Southern Pine Beetle Infested Trees, Jack E. Coster, I. R. Ragenovich Jan 1976

Effects Of Six Insecticides On Emergence Of Some Parasites And Predators From Southern Pine Beetle Infested Trees, Jack E. Coster, I. R. Ragenovich

Faculty Publications

Six insecticides (lindane, phosmet, diazinon, acephate, propoxur, and carbaryl) were tested to determine effects on predators and parasites associated with southern pine beetle, Dendroctonus frontalis Zimmerman, in eastern Texas. Eleven species of parasites and predators emerged from insecticide-treated pine bolts. The most prevalent species was Coeloides pissodis followed by Medetera lJistriata, Roptrocerus xylophagorum, Corticeus glaber, and Thanasimus dulJius. In terms of emergence from treated pines, only diazinon significantly reduced the total number of associated insects. They were 65% fewer in number following diazinon treatment. The insecticides differed in their effects on the 11 associates. C. glaber, C. pissodis, M. lJistriata, …

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Endoparasitic Nematodes Of Ips Bark Beetles In Eastern Texas, Jack E. Coster, William Hoffard Jan 1976

Endoparasitic Nematodes Of Ips Bark Beetles In Eastern Texas, Jack E. Coster, William Hoffard

Faculty Publications

East Texas Ips species contained 4 specific internal nematodes; I. avulsus (Eichhoff) were infected with Parasitylenchus avulsi Massey, I. grandicollis (Eichhoff) with Contortylenchus grandicolli (Massey) Rlihm, and I. calligraphus (Germar) with Contortylenchus elongatus (Massey) Nickle and Parasitaphelenchus sp. In all 3 bark beetles, infection peaked in July and August when 50-58% of adults from naturally attacked pine trees contained nematodes. Infection levels declined to 20-30% during January and February. Infected I. grandicollis and I. avulsus adults appeared lighter in color than noninfected adults. Nematode infection apparently delayed emergence of both sexes of I. grandicollis and females of I. avulsus. In …

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Close Coupling Test Of Classical And Semiclassical Cross Sections For Rotationally Inelastic Ar-N2 Collisions, Russell T. Pack Apr 1975

Close Coupling Test Of Classical And Semiclassical Cross Sections For Rotationally Inelastic Ar-N2 Collisions, Russell T. Pack

Faculty Publications

Accurate quantum mechanical close coupling (CC) integral cross sections are reported for rotationally inelastic Ar-N2 collisions at room temperature using an empirical intermolecular potential. These cross sections are used to test the infinite order sudden (IOS) approximation and the results of several methods [classical trajectories (CT), full sudden (SA), generalized phase shift (GPS), and classical limit generalized phase shift (CGPS)] as reported in the preceding paper by Pattengill. The IOS approximation works very well for cross sections involving low rotational states. The CT method works well for all the cross sections examined, justifying the popular belief that the rotational motion …

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Notes On Nosodendron Californicum Horn On Slime Fluxes Of Grand Fir, Abies Grandis (Douglas) Lindley, In Northern Idaho (Coleoptera: Nosodendridae), David Kulhavy, Harold Osborne Jan 1975

Notes On Nosodendron Californicum Horn On Slime Fluxes Of Grand Fir, Abies Grandis (Douglas) Lindley, In Northern Idaho (Coleoptera: Nosodendridae), David Kulhavy, Harold Osborne

Faculty Publications

Adults and larvae of Nosodendron californicum Horn were observed and collected from sap exudations on and adjacent to frost cracks of Abiesgrandis (Douglas) Lindley. This is the first published record of this species in Idaho and east of the Cascade Range in the Pacific Northwest.

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Erratum: On Improved Wkb (Uniform Asymptotic) Quantum Conditions, Dunham Corrections, The Langer Modification, And Rkr Potentials, Russell T. Pack Nov 1974

Erratum: On Improved Wkb (Uniform Asymptotic) Quantum Conditions, Dunham Corrections, The Langer Modification, And Rkr Potentials, Russell T. Pack

Faculty Publications

In Eqs. (28) and (29) p should be changed to t.

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The Vegetarian Advantage Part 2, Harald Habenicht Aug 1974

The Vegetarian Advantage Part 2, Harald Habenicht

Faculty Publications

No abstract provided.

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The Vegetarian Advantage Part 1, Harald Habenicht Jul 1974

The Vegetarian Advantage Part 1, Harald Habenicht

Faculty Publications

No abstract provided.

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Improving Height/Age Data From Stem Analysis, J. David Lenhart Jan 1974

Improving Height/Age Data From Stem Analysis, J. David Lenhart

Faculty Publications

No abstract provided.

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Needle Variation In Loblolly Pine From Mesic And Xeric Seed Sources, M. Victor Bilan, T.A. Knauf Jan 1974

Needle Variation In Loblolly Pine From Mesic And Xeric Seed Sources, M. Victor Bilan, T.A. Knauf

Faculty Publications

Anatomical modifications in protective layers and stomatal characteristics of needles which would have moisture conserving effects were found in 2-yr-old seedlings of 1oblolly pines of the Bastrop County, Texas, provenance. Most of these modifications were absent from needles of 16-yr-old trees of the same provenance. Forest Sci. 20:88-90.

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Rotationally Inelastic Molecular Scattering. Computational Tests Of Some Simple Solutions Of The Strong Coupling Problem, Thomas P. Tsien, Gregory A. Parker, Russell T. Pack Nov 1973

Rotationally Inelastic Molecular Scattering. Computational Tests Of Some Simple Solutions Of The Strong Coupling Problem, Thomas P. Tsien, Gregory A. Parker, Russell T. Pack

Faculty Publications

Partial cross sections (opacity functions) for rotational transitions in atom-diatom collisions are computed in the infinite-order sudden (IOS) approximation and compared with accurate close-coupling (CC) calculations. Agreement is good in the dominant coupling (small total angular momentum J) region. Simple methods for calculating integral inelastic cross sections are discussed, and it is found that accurate cross sections can often be computed very simply, even when large numbers of channels are coupled together, by using IOS or first-order sudden (FOS) approximations for small J and CC or exponential Born (EBDW) methods for large J.

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Systemic Insecticides Effective Against Poplar Tentmaker In Cottonwood Plantations, Jack E. Coster Jan 1973

Systemic Insecticides Effective Against Poplar Tentmaker In Cottonwood Plantations, Jack E. Coster

Faculty Publications

No abstract provided.

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On Improved Wkb (Uniform Asymptotic) Quantum Conditions, Dunham Corrections, The Langer Modification, And Rkr Potentials, Russell T. Pack Dec 1972

On Improved Wkb (Uniform Asymptotic) Quantum Conditions, Dunham Corrections, The Langer Modification, And Rkr Potentials, Russell T. Pack

Faculty Publications

An improvement to the WKB quantum condition for the rotation-vibration levels of diatomic molecules, known empirically to give RKR potentials of increased accuracy and to account for the Dunham correction Y00, is derived using uniform asymptotic methods. The role of the Langer transformation in this problem is also discussed.

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Evaluation Of Four Systemic Insecticides Against The Cottonwood Twig Borer, Jack E. Coster, Robert G. Merrifield, R.A. Woessner Apr 1972

Evaluation Of Four Systemic Insecticides Against The Cottonwood Twig Borer, Jack E. Coster, Robert G. Merrifield, R.A. Woessner

Faculty Publications

No abstract provided.

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On The Mechanism Of Low-Temperature Termolecular Atomic Recombination, Russell T. Pack, Richard L. Snow, Wesley D. Smith Jan 1972

On The Mechanism Of Low-Temperature Termolecular Atomic Recombination, Russell T. Pack, Richard L. Snow, Wesley D. Smith

Faculty Publications

A simple theory of gas-phase termolecular atomic recombination kinetics is presented which treats the bound-complex (BC) mechanism in a fashion which parallels the Roberts, Bernstein, and Curtiss resonance theory of the energy-transfer (ET) mechanism. The ET rate constant has a low temperature maximum, but the BC rate constant does not. The contributions of the two mechanisms to the low-temperature recombination of hydrogen atoms, with He, Ar, and H2 as third bodies, are estimated and compared. The presence (absence) of a low-temperature maximum in the observable total rate constant is determined by absence (presence) of bound vibrational levels of the hydrogen-third …

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Effects Of Feeding And Mating On Pheromone Release In The Southern Pine Beetle, Jack E. Coster, J.P. Vite` Jan 1972

Effects Of Feeding And Mating On Pheromone Release In The Southern Pine Beetle, Jack E. Coster, J.P. Vite`

Faculty Publications

Response of field populations of Delldroetoll1lS frontalis Zimmermann to their aggregating pheromone was correlated with pheromone content of dissectted hindgut tissues of adult beetles a determined by the gas-liquid chromatography (GLC) technique. Adult beetles in various stages of feeding activity and reproductive states were used for this purpose. Two major components of the aggregating pheromones, frontalin and trans-verbenol, were found in the largest quantities in emergent unfed females. After 48 hours of feeding, frontal in content of the hindguts was 29% and trans-verbeno content was only 5% of that of emergent females. Continuous bioassays of females feeding in host material …

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Predicting Survival Of Unthinned, Old-Field Loblolly Pine Plantations, J. David Lenhart Jan 1972

Predicting Survival Of Unthinned, Old-Field Loblolly Pine Plantations, J. David Lenhart

Faculty Publications

A prediction equation, graph, and tables can assist forest landowners in estimating tree survival in unthinned loblolly pine (Pinus Taeda L.) plantations in the Interior West Gulf coastal plain.

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An Alternative Procedure For Improving Height/Age Data From Stem Analysis, J. David Lenhart Jan 1972

An Alternative Procedure For Improving Height/Age Data From Stem Analysis, J. David Lenhart

Faculty Publications

No abstract provided.

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High-Pressure Phase Studies On Sodium–Potassium Alloys, D. Ray Anderson, J. Bevan Ott, Rex J. Goates, H. Tracy Hall Jan 1971

High-Pressure Phase Studies On Sodium–Potassium Alloys, D. Ray Anderson, J. Bevan Ott, Rex J. Goates, H. Tracy Hall

Faculty Publications

The solid–liquid phase diagrams were investigated to 60 kbar for elemental sodium, potassium, and various sodium–potassium alloys. The data for Na and K are in general agreement with those of earlier workers. In the alloy system the temperatures of both the peritectic and eutectic halts increase as the pressure increases, but with different slopes, so that the two invariant points merge at approximately 35 kbar. Above this pressure, two halts are again observed. One increases with increasing pressure, and the other decreases with increasing pressure up to 55 kbar, where it abruptly starts increasing again. Melting points for samples in …

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Two-, Three-, And Four-Particle Spatial Correlations Among Tertiary Cosmic Ray Muons, David D. Busath, R O. Stevenson Jan 1971

Two-, Three-, And Four-Particle Spatial Correlations Among Tertiary Cosmic Ray Muons, David D. Busath, R O. Stevenson

Faculty Publications

Showers of muons which result from interactions of primary cosmic rays high in the atmosphere appear deep underground as bundles of nearly parallel muons. For threshold energies of 1 TeV and arrival zenith angles of 45 degrees, those events having a small mean number of muons are described by a power law distribution in shower size having an exponent of ≅ -3.7 and a radial density distribution that decreases with distance R from the shower axis a little less rapidly than exp(-R/5.4 m). Comparison of new data on four muon spatial correlations in terms of the same phenomenology with data …

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Asymptotic Evaluation Of Wkb Matrix Elements. Ii. Use Of Langer's Uniform Asymptotic Wavefunctions, Wesley D. Smith, Russell T. Pack Feb 1970

Asymptotic Evaluation Of Wkb Matrix Elements. Ii. Use Of Langer's Uniform Asymptotic Wavefunctions, Wesley D. Smith, Russell T. Pack

Faculty Publications

An improvement in a previous procedure for the analytic asymptotic evaluation of integrals arising in the quantum-mechanical theory of inelastic molecular collisions is presented. The integrals are evaluated using Langer's uniform asymptotic wavefunctions and the higher-order saddle-point or steepest-descents method. It is found that the Langer functions give no better results than WKB functions, but the higher-order steepest-descents corrections produce a marked improvement. The result is a simple method for evaluating a large class of integrals with an error of 0.1%-2.1%.

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Production Of Aggregating Pheromones In Re-Emerged Parent Females Of The Southern Pine Beetle, Jack E. Coster Jan 1970

Production Of Aggregating Pheromones In Re-Emerged Parent Females Of The Southern Pine Beetle, Jack E. Coster

Faculty Publications

No abstract provided.

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Quasilattice Interpretation Of The Thermodynamic Properties Of Mixing Of Binary Alkali-Metal Systems, J. Bevan Ott, J. Rex Goates Nov 1969

Quasilattice Interpretation Of The Thermodynamic Properties Of Mixing Of Binary Alkali-Metal Systems, J. Bevan Ott, J. Rex Goates

Faculty Publications

Quasilattice theory was applied to heats of mixing in the six systems formed from the binary combinations of Na, K, Rb, and Cs. The alkali-metal systems are particularly well suited for a critical test of the quasi-crystalline assumption since the theoretical model for these systems is relatively simple and the thermodynamic data are fairly complex. Very good fits of the heat-of-mixing data were achieved by assuming that the larger atom in the binary system covered multiple sites on the quasilattice. The values of the empirically determined constants appear to fit the physical significance accorded to them by the quasilattice model. …

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Observations On Platypus Flavicornis (Coleoptera: Platypodidae) In Southern Pine Beedle Infestation, Jack E. Coster Jan 1969

Observations On Platypus Flavicornis (Coleoptera: Platypodidae) In Southern Pine Beedle Infestation, Jack E. Coster

Faculty Publications

No abstract provided.

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Expectation Values Of Simple Correlated Helium-Atom Wavefunctions, Thomas P. Tsien, Russell T. Pack Nov 1968

Expectation Values Of Simple Correlated Helium-Atom Wavefunctions, Thomas P. Tsien, Russell T. Pack

Faculty Publications

In this Note we present the results of a calculation of the expectation values of a number of one- and two electron properties of the ground-state helium atom using two very simple correlated wavefunctions.

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Acrylic Resin Tubes For Studying Root Growth In Tree Seedlings, M. Victor Bilan Jan 1964

Acrylic Resin Tubes For Studying Root Growth In Tree Seedlings, M. Victor Bilan

Faculty Publications

A new method was designed to study root growth of intact tree seedlings grown in acrylic resin tubes filled with soil.

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Natural Areas Of The Southeast, Laurence C. Walker Jan 1963

Natural Areas Of The Southeast, Laurence C. Walker

Faculty Publications

The following article on the status of the natural area program in the Southeastern Section (Alabama, Georgia, and Florida) is condensed from a report summarizing the progress of the Section's liaison officer (Laurence C. Walker) to the National Natural Area Committee. Each Section of our Society has such a liaison officer--some Sections have a natural area committee--who conducts the field work for the National Committee. The goal of the Committee, as well as that of cooperating agencies and organizations, is to locate and to have preserved in perpetuity, for purposes of research and education, examples of undisturbed, natural forests representing …

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