179 research outputs found
Quantal calculations on the rotational excitation of NH(_3) and OH in collisions with H(_2)
No full textResults are presented for quantal close coupled calculations of the rotational excitation of NH(_3) and OH in collisions with both ortho and para-H(_2). For the latter, these are the first calculations to include the rotational structure of the H(_2) molecule, whilst for the former, previous NH(_3) - ortho-H(_2) calculations have been subject to subsidiary approximations. The results from the NH3-H2 calculation show substantial qualitative changes in the cross-sections when ground state ortho-H(_2) (j = 1) replaces ground state para-H(_2) (j = 0) as the collision partner. In particular, cross-sections which were very small for NH(_3) - para-H(_2) collisions can be of a comparable magnitude with the other rotationally inelastic cross-sections for NH(_3) - ortho-H(_2) collisions. The changes in cross-sections are discussed in relation to the collisional pumping scheme for an astrophysical maser in the (jk = 33) inversion lines. From the OH-H(_2) calculations it is found that the propensities towards preferential excitation of a given component of the A doublets are reduced in strength when ortho-H(_2) replaces ground state para-H(_2) as the collision partner, similarly when (j = 2) para-H(_2) replaces ground state para-H(_2) the propensities are weakened. In both cases, the results are discussed in the context of crossed beam measurements at energies of 605cm(^-1)(NH(_3)-H(_2)) and 680cm(^-1) (OH-H(_2)). It is found that discrepancies between the experimental results and theoretical calculations for ground state para-H(_2) collisions can be explained, at least in part, by the neglect of the (j > 0) H(_2) rotational states in the latter
A study of vibrating-rotating motions of polyatomic molecules
No full textExact vibration-rotational eigenstates for the ground electronic state of HCN were obtained by solving the time-independent Schrodinger equation. The Hamiltonian of the system was expressed in both rectilinear and curvilinear coordinates, Potential energy surfaces were obtained from fitting either ab initio or experimental data points by a series expansion of convenient functions in the same coordinates as the kinetic energy operator. We have formulated the problem such that the variables are separable and hence the dimension of the problem is reduced to one. The energy levels were obtained variationally by using harmonic oscillator, Kratzer oscillator, and pendulum functions as basis functions. Our approach is computationally efficient and our results agrees with those published in the literature.Made available in DSpace on 2011-05-07T13:59:40Z (GMT). No. of bitstreams: 2
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Quantum mechanical molecular scattering theory: Orbiting to room temperature
No full textA series of time-independent scattering calculations were done on the helium and silicon-monoxide (B =.0901 meV) system in its ground electronic state using the rigid rotor approximation. Close Coupling results were compared with those of the L-average form of Coupled States (CS), its first order perturbational improvement, the Recoupled (RE) method, and an extension of the Exponential Distorted Wave (EDW) method called the EX method. EX used the CS solution as its zeroth order member. Four energies were studied extensively. The lowest energy, 2.25 meV (equal to.4 times the potential well-depth), produced intense orbiting behavior. At this energy, CS performed very poorly, RE performed exceedingly poorly, and EX, though improving the RE results, did not significantly improve the CS results. At an energy 4 times this, CS performed a little better and the other methods were of little added value. Two higher energies (18 meV and 27 meV) were studied. CS was excellent and RE made minor improvements. EX results were significantly worse than CS. Orbiting is shown to be the factor causing the poor results at low energy. Also, great sensitivity of cross sections to slight changes in energy in the low energy range is shown.Numerous (approx. 500) m-dependent differential cross sections are plotted. Many degeneracy averaged differential and integral cross sections are given. A 35 page table of m-dependent integral cross sections is included, as are pertinent computer programs.Made available in DSpace on 2011-05-07T12:01:36Z (GMT). No. of bitstreams: 2
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Previous issue date: 1990Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:35:38Z
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News During the 1930s: Reporting on the European Jewish Plight
No full textIn this paper, the author chronicles and asks hard questions about genocides that have taken place at various times and places, using them to illustrate how news did or did not filter into the U.S. mainstream and the consciousness of the American people.Archived web contentFriends of Drake Librar
Efficacy and Safety of Tadalafil Once Daily in the Treatment of Men With Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Hyperplasia: Results of an International Randomized, Double-Blind, Placebo-Controlled Trial
No full textBackground: Tadalafil is being investigated for the treatment of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH-LUTS). Objective: To assess efficacy, including onset, and safety of tadalafil on BPH-LUTS and the subject's and clinician's perception of changes in urinary symptoms. Design, setting, and participants: This randomized, double-blind, placebo-controlled, 12-week trial enrolled men >= 45 yr of age with BPH-LUTS for >6 mo, International Prostate Symptom Score (IPSS) >= 13, and maximum urine flow rate (Q(max)) >= 4 to <= 15 ml/s. Intervention: Tadalafil 5 mg (n = 161) or placebo (n = 164), once daily. Measurements: Analysis of covariance (ANCOVA) modeling evaluated change from baseline in continuous efficacy variables. Categoric efficacy variables were analyzed with the Cochran-Mantel-Haenszel test, and between-group differences in treatment-emergent adverse events (TEAEs) were assessed using the Fisher exact test. Results and limitation: Tadalafil significantly improved IPSS results, from baseline to endpoint, compared to placebo (-5.6 vs -3.6; p = 0.004). Reduction in IPSS results was apparent after 1 wk and significant after 4 wk (tadalafil -5.3 vs placebo -3.5; p = 0.003). The BPH Impact Index (BII) was not assessed at week 1; however, BII improvement was apparent at 4 wk (tadalafil -1.8 vs placebo -1.2; p = 0.029) and continued at 12 wk (tadalafil -1.8 vs placebo -1.3; p = 0.057). Tadalafil significantly improved the International Index of Erectile Function-Erectile Function score in sexually active men with erectile dysfunction (ED; 6.7 vs 2.0; p < 0.001) at 12 wk (not assessed at week 1). Few subjects reported one TEAE or more (p = 0.44). For tadalafil, the most common TEAEs were headache (3.7%) and back pain (3.1%). Tadalafil did not significantly improve Q(max) or reduce postvoid residual volume. Conclusions: Tadalafil 5 mg once daily for 12 wk resulted in a clinically meaningful reduction in total IPSS results as early as 1 wk and achieved statistical significance at 4 wk in men with BPH-LUTS. The adverse event profile was consistent with that previously reported in men with ED. Trial registration: This clinical trial is registered on the clinicaltrials.gov website (http://www.clinicaltrials.gov). The registration number is NCT00827242. (C) 2011 Published by Elsevier B. V. on behalf of European Association of Urology
Climate Response of Metasequoia glyptostroboides Inferred from Tree Rings, Secrest Arboretum, Wooster, Ohio, USA
No full textMetasequoia glyptostroboides, a deciduous gymnosperm, also known as dawn redwood, was thought to be extinct until living members of the species were found in China in 1943. Analyzing the climate response of a transplanted stand of the trees can give insights into their physiological plasticity, into their use in restoration and reforestation, as well as into interpreting the environmental conditions of the geologic past from fossil Metasequoia. An annual ring-width chronology—spanning 1955 to 2010 and based on a stand of 19 M. glyptostroboides trees planted in Secrest Arboretum in northeast Ohio, USA—shows negative correlations with maximum monthly temperatures: with the strongest relationship with February and the warm months of June and July, all significant at the 99% confidence levels. A positive May to June precipitation correlation is the strongest moisture signal (p < 0.05) and the narrowest rings in the chronology occurred during the drought of 1987 to 1988, consistent with one of the warmest and driest Junes on record. These results have implications for the future as climate change affects the native and transplanted range of this species. Future response of this species to a changing climate will depend on the relative rates of warming maximum temperatures in the winter and summer, as well as changing moisture conditions during the summer months
VLBI position variability of AGNs is inversely correlated with their photometric variability
No full textAims. The stability of the International Celestial Reference Frame (ICRF), realized through geodetic very long baseline interferometry (VLBI) positions of thousands of extragalactic objects, is dependent on the individual positional stability of these objects. It has been recently shown that the prevalence of offsets between the VLBI positions of ICRF objects and their Gaia optical positions, which limit the optical-radio reference frame tie, is inversely correlated with optical photometric variability, suggesting that photometrically variable objects may be more positionally stable. In this work, we determine the relationship between VLBI position stability of ICRF objects and optical-radio position offsets as well as optical photometric variability.
Methods. We created multi-epoch geodetic VLBI solutions for a sample of 520 ICRF sources that have sufficient data to determine the variability in their VLBI positions over time. We compared this position variability with the fractional photometric variability provided by the Gaia extragalactic source catalog, the Gaia-ICRF optical-radio position offsets, the uncertainty-normalized position offsets, and optical BP-RP color as well as with possible confounders such as optical magnitude, VLBI/Gaia position error, and redshift. We determined the relationship between VLBI position stability and γ-ray detection by the Fermi Large Area Telescope (LAT), and we determined how the VLBI position and optical flux variabilities correlate with the spectral classification of our sample, considering flat spectrum radio quasars (FSRQs), quasi-stellar objects, BL Lacs, Seyfert, and gigahertz-peaked spectrum radio sources or compact-steep-spectrum radio sources.
Results. We found that VLBI astrometric variability is (i) negatively correlated with optical flux variability, (ii) positively correlated with optical-radio offsets, (iii) negatively correlated with optical color index BP-RP, and (iv) negatively correlated with γ-ray detection. We also found that the most positionally stable sources are among the FSRQ and BL Lac classes. In other words, redder, photometrically variable sources have the most stable VLBI positions, the smallest optical-radio position offsets, and the highest rate of γ-ray detection, and these sources tend to be spectrally classified as blazars.
Conclusions. Our results are consistent with the most positionally stable sources being blazars, a class of object in which the jet is oriented close to the line of sight and where relativistic beaming increases photometric variability and minimizes the projected offset between the optical and radio positions. Our study should therefore orient future geodetic VLBI observing programs preferentially toward sources with high photometric variability because these sources are predicted to have better VLBI position stabilities and smaller optical-radio position offsets, improving the stability of the celestial reference frame axes
A Seasoned Instructors New Look At Fixed-Income Securities: An Exercise Using Discounted Bonds
No full textHaving returned to teaching the basics of pricing fixed-income securities after several years, the author recalls the difficulty students have in understanding the total return provided by fixed-income securities that are purchased at either a discount or premium from face value.This teaching note attempts to clarify the concept by suggesting that separation of the return provided by coupon payments from the return provided by periodic changes in the fair market value may aid in student understanding.The integration of financial calculators in the classroom improves and simplifies this process for seasoned instructors
Personal Papers (MS 80-0002)
No full textLetter from Isaac Herbert Kempner to Mike Secrest stating that the writer, Mr. Lee Kempner, and Mr. Harris Kempner are not available to attend the Salute to Industry Committee meeting
Criminal Law
No full textThis article analyzes the evolving landscape of criminal law in the mid-1990s, focusing on significant legislative changes and their implications for justice and public safety. It addresses the impact of tough-on-crime policies and the growing emphasis on law enforcement and incarceration. The author critiques the balance between protecting community interests and upholding individual rights, particularly in light of recent judicial rulings. Through an examination of notable cases, the author highlights issues such as due process, sentencing disparities, and the role of discretion in the criminal justice system. Ultimately, it advocates for reforms aimed at ensuring a more equitable and effective approach to criminal law
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