Effect of 2-Substitution on the Rearrangement of 1-Cyclopropylvinyl Cations

2-Substitution in 1-cyclopropylvinyl cations produces a steric effect on cation generation and solvent trapping, but an electronic charge-stabilizing effect on cyclopropyl-to-cyclobutyl rearrangement

Telescope Time Without Tears: A Distributed Approach to Peer Review

The procedure that is currently employed to allocate time on telescopes is horribly onerous on those unfortunate astronomers who serve on the committees that administer the process, and is in danger of complete collapse as the number of applications steadily increases. Here, an alternative is presented, whereby the task is distributed around the astronomical community, with a suitable mechanism design established to steer the outcome toward awarding this precious resource to those projects where there is a consensus across the community that the science is most exciting and innovative.Comment: 9 pages, accepted for publication in Astronomy & Geophysic

Analysis and identification of subsynchronous vibration for a high pressure parallel flow centrifugal compressor

The summary of a complete analytical design evaluation of an existing parallel flow compressor is presented and a field vibration problem that manifested itself as a subsynchronous vibration that tracked at approximately 2/3 of compressor speed is reviewed. The comparison of predicted and observed peak response speeds, frequency spectrum content, and the performance of the bearing-seal systems are presented as the events of the field problem are reviewed. Conclusions and recommendations are made as to the degree of accuracy of the analytical techniques used to evaluate the compressor design

Why Do Real Estate Master Limited Partnerships Seem to be Undervalued?

This study investigates one reason why real estate master limited partnerships (MLPs) are undervalued. The study finds that parents of MLPs, generally, and parents of non-real estate MLPs experience positive stock price increases when creating MLPs in the same business as the parent firm and insignificant price increases otherwise. Parents of real estate MLPs experience insignificant stock price changes whether or not the MLP is in the same business as the parent firm. However, despite insignificance, we find evidence that real estate parents forming real estate MLPs may experience greater stock price appreciation than non-real estate parents creating real estate MLPs.

Missouri farm prices and purchasing power

Publication authorized February 26, 1926.Includes bibliographical references

Aging, Emotion, Attention, and Binding in the Taboo Stroop Task: Data and Theories.

How does aging impact relations between emotion, memory, and attention? To address this question, young and older adults named the font colors of taboo and neutral words, some of which recurred in the same font color or screen location throughout two color-naming experiments. The results indicated longer color-naming response times (RTs) for taboo than neutral base-words (taboo Stroop interference); better incidental recognition of colors and locations consistently associated with taboo versus neutral words (taboo context-memory enhancement); and greater speed-up in color-naming RTs with repetition of color-consistent than color-inconsistent taboo words, but no analogous speed-up with repetition of location-consistent or location-inconsistent taboo words (the consistency type by repetition interaction for taboo words). All three phenomena remained constant with aging, consistent with the transmission deficit hypothesis and binding theory, where familiar emotional words trigger age-invariant reactions for prioritizing the binding of contextual features to the source of emotion. Binding theory also accurately predicted the interaction between consistency type and repetition for taboo words. However, one or more aspects of these phenomena failed to support the inhibition deficit hypothesis, resource capacity theory, or socio-emotional selectivity theory. We conclude that binding theory warrants further test in a range of paradigms, and that relations between aging and emotion, memory, and attention may depend on whether the task and stimuli trigger fast-reaction, involuntary binding processes, as in the taboo Stroop paradigm

Photolytically generated aerosols in the mesosphere and thermosphere of Titan

Analysis of the Cassini Ultraviolet Imaging Spectrometer (UVIS) stellar and solar occultations at Titan to date include 12 species: N$_{2}$ (nitrogen), CH$_{4}$ (methane), C$_{2}$H$_{2}$ (acetylene), C$_{2}$H$_{4}$ (ethylene), C$_{2}$H$_{6}$ (ethane), C$_{4}$H$_{2}$ (diacetylene), C$_{6}$H$_{6}$ (benzene), C$_{6}$N$_{2}$ (dicyanodiacetylene), C$_{2}$N$_{2}$ (cyanogen), HCN (hydrogen cyanide), HC$_{3}$N (cyanoacetylene), and aerosols distinguished by a structureless continuum extinction (absorption plus scattering) of photons in the EUV. The introduction of aerosol particles, retaining the same refractive index properties as tholin with radius $\sim$125 \AA and using Mie theory, provides a satisfactory fit to the spectra. The derived vertical profile of aerosol density shows distinct structure, implying a reactive generation process reaching altitudes more than 1000 km above the surface. A photochemical model presented here provides a reference basis for examining the chemical and physical processes leading to the distinctive atmospheric opacity at Titan. We find that dicyanodiacetylene is condensable at $\sim$650 km, where the atmospheric temperature minimum is located. This species is the simplest molecule identified to be condensable. Observations are needed to confirm the existence and production rates of dicyanodiacetylene.Comment: A typo in Table 1 was made in the previous version. The corrected tholin abundance is 4.6x10^11. ApJL in press. Will be published on June 1st, or May 21 onlin

Neonatal growth of Steller sea lion (Eumetopias jubatus) pups in Alaska

The growth rate of Steller sea lion (Eumetopias jubatus) pups was studied in southeast Alaska, the Gulf of Alaska, and the Aleutian Islands during the first six weeks after birth. The Steller sea lion population is currently stable in southeast Alaska but is declining in the Aleutian Islands and parts of the Gulf of Alaska. Male pups (22.6 kg [±2.21 SD]) were significantly heavier than female pups (19.6 kg [±1.80 SD]) at 1−5 days of age, but there were no significant differences among rookeries. Male and female pups grew (in mass, standard length, and axillary girth) at the same rate. Body mass and standard length increased at a faster rate for pups in the Aleutian Islands and the western Gulf of Alaska (0.45−0.48 kg/day and 0.47−0.53 cm/day, respectively) than in southeast Alaska (0.23 kg/day and 0.20 cm/day). Additionally, axillary girth increased at a faster rate for pups in the Aleutian Islands (0.59 cm/ day) than for pups in southeast Alaska v(0.25 cm/day). Our results indicate a greater maternal investment in male pups during gestation, but not during early lactation. Although differences in pup growth rate occurred among rookeries, there was no evidence that female sea lions and their pups were nutritionally stressed in the area of population declin

Reaction kinetics of muonium with the halogen gases (F2, Cl2, and Br2)

Copyright @ 1989 American Institute of PhysicsBimolecular rate constants for the thermal chemical reactions of muonium (Mu) with the halogen gases—Mu+X2→MuX+X—are reported over the temperature ranges from 500 down to 100, 160, and 200 K for X2=F2,Cl2, and Br2, respectively. The Arrhenius plots for both the chlorine and fluorine reactions show positive activation energies Ea over the whole temperature ranges studied, but which decrease to near zero at low temperature, indicative of the dominant role played by quantum tunneling of the ultralight muonium atom. In the case of Mu+F2, the bimolecular rate constant k(T) is essentially independent of temperature below 150 K, likely the first observation of Wigner threshold tunneling in gas phase (H atom) kinetics. A similar trend is seen in the Mu+Cl2 reaction. The Br2 data exhibit an apparent negative activation energy [Ea=(−0.095±0.020) kcal mol−1], constant over the temperature range of ∼200–400 K, but which decreases at higher temperatures, indicative of a highly attractive potential energy surface. This result is consistent with the energy dependence in the reactive cross section found some years ago in the atomic beam data of Hepburn et al. [J. Chem. Phys. 69, 4311 (1978)]. In comparing the present Mu data with the corresponding H atom kinetic data, it is found that Mu invariably reacts considerably faster than H at all temperatures, but particularly so at low temperatures in the cases of F2 and Cl2. The current transition state calculations of Steckler, Garrett, and Truhlar [Hyperfine Interact. 32, 779 (986)] for Mu+X2 account reasonably well for the rate constants for F2 and Cl2 near room temperature, but their calculated value for Mu+Br2 is much too high. Moreover, these calculations seemingly fail to account for the trend in the Mu+F2 and Mu+Cl2 data toward pronounced quantum tunneling at low temperatures. It is noted that the Mu kinetics provide a crucial test of the accuracy of transition state treatments of tunneling on these early barrier HX2 potential energy surfaces.NSERC (Canada), Donors of the Petroleum Research Fund, administered by the American Chemical Society, for their partial support of this research and the Canada Council

Blue horizontal branch stars in the Sloan Digital Sky Survey: II. Kinematics of the Galactic halo

We carry out a maximum-likelihood kinematic analysis of a sample of 1170 blue horizontal branch (BHB) stars from the Sloan Digital Sky Survey presented in Sirko et al. (2003) (Paper I). Monte Carlo simulations and resampling show that the results are robust to distance and velocity errors at least as large as the estimated errors from Paper I. The best-fit velocities of the Sun (circular) and halo (rotational) are 245.9 +/- 13.5 km/s and 23.8 +/- 20.1 km/s but are strongly covariant, so that v_0 - v_halo = 222.1 +/- 7.7 km/s. If one adopts standard values for the local standard of rest and solar motion, then the halo scarcely rotates. The velocity ellipsoid inferred for our sample is much more isotropic [(sigma_r,sigma_theta,sigma_phi) = (101.4 +/- 2.8, 97.7 +/- 16.4, 107.4 +/- 16.6) km/s] than that of halo stars in the solar neighborhood, in agreement with a recent study of the distant halo by Sommer-Larsen et al. (1997). The line-of-sight velocity distribution of the entire sample, corrected for the Sun's motion, is accurately gaussian with a dispersion of 101.6 +/- 3.0 km/s.Comment: 23 pages including 4 figures, 1 color; submitted to A