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Articles 21361 - 21390 of 21971

Full-Text Articles in Physical Sciences and Mathematics

Introduction: Structural Properties For Determining Mechanisms Of Toxic Action, Steven P. Bradbury, Robert L. Lipnick Jan 1990

Introduction: Structural Properties For Determining Mechanisms Of Toxic Action, Steven P. Bradbury, Robert L. Lipnick

Steven P. Bradbury

The U.S. Environmental Protection Agency (EPA), under a variety of Federal legislation, is charged with the responsibility of assessing the hazards of chemicals to human health and the environment. In some cases EPA incorporates predictive techniques in its decisionmaking processes. In the context of some statutes, predictive toxicological methods can be cost-effective components in an overall approach for prioritizing chemicals for in-depth toxicological investigation. Predictive approaches are also used where empirical toxicological data are either unavailable or not required under a specific statute. For example, under Section 5 of the Toxic Substances Control Act (TSCA), EPA's Office of Toxic Substances …


Influence Of Cytochrome P450 Mixed-Function Oxidase Induction On The Acute Toxicity To Rainbow Trout (Salmo Gairdneri) Of Primary Aromatic Amines, Steven P. Bradbury, Joop L. M. Hermens, Steven J. Broderius Jan 1990

Influence Of Cytochrome P450 Mixed-Function Oxidase Induction On The Acute Toxicity To Rainbow Trout (Salmo Gairdneri) Of Primary Aromatic Amines, Steven P. Bradbury, Joop L. M. Hermens, Steven J. Broderius

Steven P. Bradbury

The influence of enzyme induction on the acute toxicity of aniline and 4-chloroaniline to rainbow trout (Salmo gairdneri) was investigated. For these two xenobiotics, bioactivation reactions are known to occur in mammals. Induction of cytochrome P450 mixed-function oxidase was obtained by intraperitoneal (ip) injection of trout with a mixture of polychlorinated biphenyls (Aroclor 1254). Five days after ip injection with three different doses of Aroclor 1254 (50. 100. and 200 mg/kg). benzo[a)pyrene hydroxylase activity in trout liver microsomes increased five- to sixfold. Cytochrome P450 concentrations in the microsomes were slightly. but significantly. enhanced in two of the three dose levels. …


Coincidence Orientations Of Crystals In Tetragonal Systems, With Applications To Yba2cu3o7, Abha Singh, N. Chandrasekhar, Alexander H. King Jan 1990

Coincidence Orientations Of Crystals In Tetragonal Systems, With Applications To Yba2cu3o7, Abha Singh, N. Chandrasekhar, Alexander H. King

Alexander H. King

We have developed a method for the characterization of coincidence-site lattices (CSL's) in tetragonal or near-tetragonal orthorhombic structures, by suitable modifications to the method of Grimmer & Warrington [Acta Cryst. (1987), A43, 232-243]. We have applied our method to determine coincidence rotations and the associated information appropriate for forming constrained CSL's in the high-To superconductor YBazCu307-n. The unit cell is orthorhombic with lattice parameters a = 3.82, b = 3"89 and c = 11.67 A for the nominal composition. We present tables of coincidence rotation angles, .Z, CSL, DSCL and associated step vectors up to ,~ = 50. We find …


Hyperfine Structure Of The Mnh X 7-Sigma(+) State: A Large Gas-To-Matrix Shift In The Fermi Contact Interaction, Thomas Varberg, R. Field, A. Merer Jan 1990

Hyperfine Structure Of The Mnh X 7-Sigma(+) State: A Large Gas-To-Matrix Shift In The Fermi Contact Interaction, Thomas Varberg, R. Field, A. Merer

Thomas D. Varberg

No abstract provided.


Inhomogeneous Broadening In Spectral Bands Of Carbonmonoxymyoglobin: The Connection Between Spectral And Functional Heterogeneity, Todd B. Sauke, P. Ormos, A. Ansari, D. Braunstein, B. R. Cowen, H. Fraunfelder, M. K. Hong, I. E. T. Iben, P. J. Steinbach, R. D. Young Jan 1990

Inhomogeneous Broadening In Spectral Bands Of Carbonmonoxymyoglobin: The Connection Between Spectral And Functional Heterogeneity, Todd B. Sauke, P. Ormos, A. Ansari, D. Braunstein, B. R. Cowen, H. Fraunfelder, M. K. Hong, I. E. T. Iben, P. J. Steinbach, R. D. Young

Todd B. Sauke

The rebinding kinetics of CO to myoglobin after flash photolysis is nonexponential in time below approximately 180 K; the kinetics is governed by a distribution of enthalpic barriers. This distribution results from inhomogeneities in the protein conformation, referred to as conformational substates. Hole-burning experiments on the Soret and IR CO-stretch bands test the assumption that an inhomogeneous distribution of conformational substates results in inhomogeneously broadened spectra. CO was slowly photolyzed at different wavelengths in the Soret band at 10 K. Both the Soret band and the CO-stretch band A1, centered at 1,945 cm-1, shift during photolysis, demonstrating that different wavelengths …


Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick Jan 1990

Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick

Michael Sinensky

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. …


Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser Jan 1990

Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser

June Ann Oberdorfer

No abstract provided.


Seasonal Variations In Theequatorial Thermospheric Wind Measured At Arequipa, Peru, M. A. Biondi, J. W. Meriwether, Bela G. Fejer, S. A. Gonzalez Jan 1990

Seasonal Variations In Theequatorial Thermospheric Wind Measured At Arequipa, Peru, M. A. Biondi, J. W. Meriwether, Bela G. Fejer, S. A. Gonzalez

Bela G. Fejer

Studies have been carried out at Arequipa, Peru, of the seasonal variations in the thermospheric winds at moderate solar flux levels and low geomagnetic activity. Fabry-Perot interferometer measurements of the Doppler shifts in the 630.0 nm nightglow emission line from March to August 1983 and from April to October 1988 have yielded monthly-average meridional winds that are nearly zero (<50 m/s) and possibly fluctuating in direction through much of the night but develop a southward flow at 50–100 m/s in the early and the late night from May onward. The average zonal winds are eastward throughout the night, reaching peak velocities before local midnight and then decreasing. The peak velocities increase to a maximum around the June solstice. The winds are generally stronger in 1988 than in 1983, even though the solar EUV fluxes are comparable for both years. Comparison of the present results with earlier satellite measurements, as embodied in the Horizontal Wind Model of Hedin et al., reveals generally satisfactory agreement at the equinox and June solstice, except for the June 1988 period. Killeen et al.'s vector spherical harmonic form of the NCAR Thermospheric General Circulation Model, calculated for similar solar flux levels, yields meridional and zonal wind variations which exhibit the same temporal behaviors but generally smaller values than the present measurements. The present wind patterns are also compared with those measured during the same years at Arecibo, Puerto Rico; one finds oppositely directed meridional flows and similar, eastward zonal flows at the two locations, as expected from a consideration of solar EUV heating as the principal driving force.


The Vcl Hypothesis Revisited: Patterns Of Femoral Morphology Among Quadrupedal And Saltatorial Prosimian Primates, Robert Anemone Dec 1989

The Vcl Hypothesis Revisited: Patterns Of Femoral Morphology Among Quadrupedal And Saltatorial Prosimian Primates, Robert Anemone

Robert L. Anemone

The descriptive and functional morphology of the postcranium of the vertical clinging and leaping prosimians is of great interest in both adaptational and phylogenetic studies of extant and extinct primates. An analysis of patterns of femoral morphology among quadrupedal and saltatory living prosimians indicates the presence of at least two, and possibly three, distinct femoral adaptations to the demands of an arboreal, saltatory existence. Osteological measurements were taken on 277 postcranial skeletons representing eight prosimian families, with skeletal trunk length (Biegert and Maurer, Folia Primatol. 17:142–156, 1972) used as an estimator of body size in both bivariate and multivariate (discriminant …


A Method For Assessing Software Measurement Technology, Robert Yacobellis Dec 1989

A Method For Assessing Software Measurement Technology, Robert Yacobellis

Robert H Yacobellis

No abstract provided.


Interpolation And Spectra Of Regular Lp-Space Operators, Karen Saxe Dec 1989

Interpolation And Spectra Of Regular Lp-Space Operators, Karen Saxe

Karen Saxe

No abstract provided.


The Zero Momentum Limit Of The Vacuum Polarization At Finite Temperature, Ps Gribosky, Br Holstein Dec 1989

The Zero Momentum Limit Of The Vacuum Polarization At Finite Temperature, Ps Gribosky, Br Holstein

Barry R Holstein

We examine the zero momentum limit of the finite temperature vacuum polarization for a quantized scalar field coupled to a classical external field. Ordinarily, this type of Feynman diagram is plagued by nonanalytic behaviour when the external momentum tends to zero. Using imaginary-time, we show that this behaviour is not present in an exact background field solution and how the Feynman diagram calculation may be trivially modified to match the exact solution. Comparisons with recent real-time results are also made.


Petrology And Provenance Of Miocene Sedimentary Rocks, Point Sur, California: Implications For Offset Along The San Gregorio-Hosgri Fault Zone, Mark Sutherland Dec 1989

Petrology And Provenance Of Miocene Sedimentary Rocks, Point Sur, California: Implications For Offset Along The San Gregorio-Hosgri Fault Zone, Mark Sutherland

Mark Sutherland

No abstract provided.


Why December 21 Is The Longest Day Of The Year, Stan Wagon Dec 1989

Why December 21 Is The Longest Day Of The Year, Stan Wagon

Stan Wagon, Retired

No abstract provided.


A Warning For The Wagner Polarization Cell, Michael Setter, J. Akridge, M. Balkanski Dec 1989

A Warning For The Wagner Polarization Cell, Michael Setter, J. Akridge, M. Balkanski

Michael P. Setter

No abstract provided.


Radiative K13 Decays And Chiral Symmetry, Br Holstein Dec 1989

Radiative K13 Decays And Chiral Symmetry, Br Holstein

Barry R Holstein

No abstract provided.


Editor's Corner: The Euclidean Algorithm Strikes Again, Stan Wagon Dec 1989

Editor's Corner: The Euclidean Algorithm Strikes Again, Stan Wagon

Stan Wagon, Retired

No abstract provided.


Parallel Machines: Parallel Machine Languages, Robert Iannucci Dec 1989

Parallel Machines: Parallel Machine Languages, Robert Iannucci

Robert A Iannucci

No abstract provided.


Efficient Application Of The Schauder-Tychonoff Theorem To Systems Of Functional Differential Equations, William F. Trench Dec 1989

Efficient Application Of The Schauder-Tychonoff Theorem To Systems Of Functional Differential Equations, William F. Trench

William F. Trench

No abstract provided.


Bivariate C1 Quadratic Finite Elements And Vertex Splines, Tian-Xiao He Dec 1989

Bivariate C1 Quadratic Finite Elements And Vertex Splines, Tian-Xiao He

Tian-Xiao He

No abstract provided.


What One Intelligence Test Measures: A Theoretical Account Of The Processing In The Raven Progressive Matrices Test, Patricia A. Carpenter, Marcel Adam Just, Peter Shell Dec 1989

What One Intelligence Test Measures: A Theoretical Account Of The Processing In The Raven Progressive Matrices Test, Patricia A. Carpenter, Marcel Adam Just, Peter Shell

Marcel Adam Just

No abstract provided.


Spectral Evolution Of A One-Parameter Extension Of A Real Symmetric Toeplitz Matrix, William F. Trench Dec 1989

Spectral Evolution Of A One-Parameter Extension Of A Real Symmetric Toeplitz Matrix, William F. Trench

William F. Trench

No abstract provided.


Forces And Policy Issues Affecting Forest Use In Northeast Thailand 1900-1985, James A. Hafner Emeritus Professor Dec 1989

Forces And Policy Issues Affecting Forest Use In Northeast Thailand 1900-1985, James A. Hafner Emeritus Professor

James A Hafner

No abstract provided.


Jual Hammer Of Thor Asli Di Bali 0821-6765-4444 Denpasar Cod, Rt Satu, Hammer Of Thor Asli 22227096 Dec 1989

Jual Hammer Of Thor Asli Di Bali 0821-6765-4444 Denpasar Cod, Rt Satu, Hammer Of Thor Asli 22227096

TOKO OBAT VITALITAS BALI

Jual Hammer Of Thor Asli Di Bali
Toko – Agen – Jual Obat Hammer Of Thor Asli Di Bali Denpasar 0821-67654444 | Alamat Toko Obat Vitalitas Hammer Of Thor Original Di Denpasar Bali | Tempat Agen Obat Kuat Hammer Of Thor Di Bali | Jual Obat Pembesar Penis Resmi Hammer Of Thor Di Denpasar Bali Siap COD / Antar Gratis
Jual Hammer Of Thor Asli Di Bali | Agen Obat Hammer Thor’s Asli Di Bali | Jual Obat Kuat Hammer Of Thor Di Bali | Obat Pria Hammer Of Thor Asli Di Denpasar | Ciri Ciri Hammer Of Thor Asli Di Bali …


Positive Residues Involved In The Voltage-Gating Of The Mitochondrial Porin-Channel Are Localized In The External Moiety Of The Pore, Philadelphia University Dec 1989

Positive Residues Involved In The Voltage-Gating Of The Mitochondrial Porin-Channel Are Localized In The External Moiety Of The Pore, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


A Note On A Toeplitz Inversion Formula, William F. Trench Dec 1989

A Note On A Toeplitz Inversion Formula, William F. Trench

William F. Trench

No abstract provided.


Http://Www.Guidemehealth.Com/Anamax-Male-Enhancement/, Naeck Kamcne Dec 1989

Http://Www.Guidemehealth.Com/Anamax-Male-Enhancement/, Naeck Kamcne

Naeck Kamcne

Probably at this time being bought within Anamax Male Enhancement the market encompass Dr. Joel's Penis development capsules, Vimax Penis medicines development, Magna Rx Plus, pro-Plus Male Enhancement pill, Bonded Labs super LQ Penis development method, PROSOLUTION, NxCare, Erexor, and plenty of others. With a discount, male .


Comparison Of Conjoint Analysis, Multiple Regression Models With Person Vectors And Profile Analysis To Assess Important Factors Used To Select Colleges, John Fraas, Isadore Newman Dec 1989

Comparison Of Conjoint Analysis, Multiple Regression Models With Person Vectors And Profile Analysis To Assess Important Factors Used To Select Colleges, John Fraas, Isadore Newman

John W. Fraas

The purpose of this study was to investigate the relative effectiveness of the traditional conjoint analysis approach to the multiple regression approach that includes person vectors and profile analysis. It was expected that the more sophisticated models would increase the effectiveness in terms of its shrinkage estimates and the accuracy of its predictability of two holdout groups. The data source consisted of a sample of 100 students who rated eight colleges on five attributes -- quality of education, financial aid, quality of dorm life, student/faculty relations, and social life.


Ripoplex Male Enhancement (Reviews 2019):, Edam Smith Dec 1989

Ripoplex Male Enhancement (Reviews 2019):, Edam Smith

edam smith

The failure to perform well in the room can murder the certainty of any man. He will begin feeling very low and embarrassed with self. Also, this will hamper his day by day life and exercises. Erectile brokenness is a typical issue with numerous men. More often than not, the issue begins exasperating with age. In any case, right now, there are different factors as well, that add to the issue. These incorporate pressure, over the top smoking, and drinking, poor way of life, and so forth. Alongside these, there are issues like anxiety, dread of shame and low testosterone …


An Analogue In Certain Unique Factorization Domains Of The Euclid-Euler Theorem On Perfect Numbers, Wayne L. Mcdaniel Dec 1989

An Analogue In Certain Unique Factorization Domains Of The Euclid-Euler Theorem On Perfect Numbers, Wayne L. Mcdaniel

UMSL Emeritus

We show that there exists a natural extention of the sum of divisors function to all unique factorization domains F having a finite number of units such that if a perfect number in F is defined to be an integer η whose proper divisors sum to η, then the analogue of Euclid's theorem giving the sufficient condition that an integer be an even perfect number holds in F, and an analogue of the Euclid-Euler theorem giving the necessary and sufficient condition that an even integer be perfect holds in those domains having more than two units, i. e., in Q(−1) …