cssi/SciSciGPT-SciSciNet huggingface dataset:
The electronic spectroscopy and photophysics of saturated phosphines

Abstract The near-UV absorption spectra of PH 3 and its trialkylderivatives trimethylphosphine (TMP), triethylphosphine (TEP), and tri- n -propylphosphine (TPP) are reported for the gas phase between 42 000 and 54 000 cm −1 . The diffuse structure observed in the spectrum of PH 3 is enhanced using second derivative (SD) spectroscopy, and the locations of 14 features are reported. The spacing between the lowest eight features (44 504 and 49 456 cm −1 ) is approximately constant, 707 ± 15 cm −1 . The absorption spectra of the trialkylphosphines are completely diffuse, and are devoid of SD features. The absorption spectra shift to lower energies with increasing alkylation. Absorption maxima (and extinction coefficients) for TMP, TEP, and TPP are 49 850 (1.5 × 10 4 ), 48 080 (9.0 × 10 3 ), and 47 620 (6.0 × 10 3 ) cm −1 ( M −1 cm −1 ). Unlike the saturated amines, which are strongly fluorescent in the gas phase, the trialkylphosphines do not produce measurable emission. An upper limit of 10 −4 is placed on the emission quantum efficiency. TPP was found to quench the fluorescence of N,N -dimethyloctylamine with a rate constant of 8.5 × 10 8 , M −1 s −1 in n -hexane solution at 283 K; this corresponds to ca. 0.042 times the diffusion-controlled value and 0.20 times the self-quenching rate constant of the amine.
Oxidation of phenylhydrazones of α-keto esters with hypervalent organoiodine reagents

Abstract α-Ketoacids and ketones can easily be regenerated in high yield from their phenylhydrazones via hydroxy azo compounds upon oxidation with hupervalent iodine reagents.
Planar Velocimetry of a Fin Trailing Vortex in Subsonic Compressible Flow

A subscale experiment has studied the trailing vortex shed from a tapered fin installed on a wind-tunnel wall to represent missile configurations. Stereoscopic particle image velocimetry data have been acquired for several locations downstream of the fin and at different fin angles of attack. The vortex's tangential velocity decays with downstream distance while its radius increases, but the vortex core circulation remains constant. Circulation and tangential velocity rise greatly for increased fin angle of attack, whereas the radius remains approximately constant or slightly decreasing. The vortex axial velocity is always a deficit, whose magnitude diminishes with downstream distance and smaller angle of attack. No variation with Mach number can be discerned in the normalized velocity data. Vortex roll up is largely complete by about four root chord lengths downstream of the fin trailing edge; before this point, the vortex is asymmetric in the tangential velocity but the core radius stays nearly uniform. Vortical rotation draws low-speed turbulent fluid from the wind-tunnel wall boundary layer and the fin wake toward the vortex core, which appears to hasten vortex decay and produce a larger axial velocity deficit than expected. Self-similarity of the vortex is established even while it is still rolling up.
GOPEX: a deep-space optical communications demonstration with the Galileo spacecraft

The Galileo Optical communications from an Earth-based Xmtr (GOPEX) demonstration is designed to exhibit deep-space optical communications using the Galileo spacecraft. The optical transmitter consists of a Nd:YAG laser coupled to a 24-in. telescope at the Table Mountain Observatory (TMO), and the receiver is the Solid-State Imaging camera on board Galileo. The objectives of the demonstration are to understand the issues involved in blind-pointing to a spacecraft in deep space, and to assess the quality of the optical uplink by comparing the experimental results with theoretical predictions. The demonstration is proposed for December 1992 during the second earth-flyby period of Galileo''s trajectory.
Anomalous hall effect of calcium-doped lanthanum cobaltite films

The Hall resistivity, magnetoresistance, and magnetization of La1−xCaxCoO3 epitaxial films with 0.25⩾x⩾0.4 grown on lanthanum aluminate were measured in fields up to 7 T. The x=1/3 film shows a reentrant metal insulator transition. Below 100 K, the x=1/3 and 0.4 films have significant coercivity which increases with decreasing temperature. At low temperature the Hall resistivity remains large and essentially field independent in these films, except for a sign change at the coercive field that is more abrupt than the switching of the magnetization. A unique magnetoresistance behavior accompanies this effect. These results are discussed in terms of a percolation picture and the mixed spin state model for this system. We propose that the low-temperature Hall effect is caused by spin-polarized carriers scattering off of orbital disorder in the spin-ordered clusters.
Effect of canopy-air interface roughness on HF-VHF wave propagation in forest

The problem of electromagnetic wave propagation in a realistic forest environment in the high-frequency and very high-frequency bands is considered. In particular, the effect of the nonplanar interface between the air and the canopy, which has been ignored in previous models, is examined. An analytical formulation is obtained for the mean field when both the transmitter and the receiver are within the foliage. This formulation is based on distorted Born approximation and accounts for the surface roughness that exists between the canopy and air interface. It is shown that the surface roughness attenuates the so-called lateral wave slightly, which is the dominant source of the field at receiver locations far from the transmitter. It is also shown that this attenuation rate increases when the RMS height of the surface roughness is increased.
Ejection of Supermassive Black Holes from Galaxy Cores

[Abridged] Recent numerical relativity simulations have shown that the emission of gravitational waves during the merger of two supermassive black holes (SMBHs) delivers a kick to the final hole, with a magnitude as large as 4000 km/s. We study the motion of SMBHs ejected from galaxy cores by such kicks and the effects on the stellar distribution using high-accuracy direct N-body simulations. Following the kick, the motion of the SMBH exhibits three distinct phases. (1) The SMBH oscillates with decreasing amplitude, losing energy via dynamical friction each time it passes through the core. Chandrasekhar's theory accurately reproduces the motion of the SMBH in this regime if 2 < ln Lambda < 3 and if the changing core density is taken into account. (2) When the amplitude of the motion has fallen to roughly the core radius, the SMBH and core begin to exhibit oscillations about their common center of mass. These oscillations decay with a time constant that is at least 10 times longer than would be predicted by naive application of the dynamical friction formula. (3) Eventually, the SMBH reaches thermal equilibrium with the stars. We estimate the time for the SMBH's oscillations to damp to the Brownian level in real galaxies and infer times as long as 1 Gyr in the brightest galaxies. Ejection of SMBHs also results in a lowered density of stars near the galaxy center; mass deficits as large as five times the SMBH mass are produced for kick velocities near the escape velocity. We compare the N-body density profiles with luminosity profiles of early-type galaxies in Virgo and show that even the largest observed cores can be reproduced by the kicks, without the need to postulate hypermassive binary SMBHs. Implications for displaced AGNs and helical radio structures are discussed.
Surface Optomechanics: Calculating Optically Excited Acoustical Whispering Gallery Modes in Microspheres

We numerically calculate mechanical whispering-gallery modes in a micron-scale silica sphere revealing Rayleigh, transverse, and longitudinal deformations. Experimentally observed modes vibrating at frequencies from 50MHz to 12 GHz will be shown next to their calculated mode.
Asymptotic theory of strong spin–orbit coupling in optical fiber

The spin–orbit coupling of light propagating in optical fiber can be dramatically enhanced by the presence of a high-contrast interface in the refractive index profile, even for modes that are highly paraxial. The resulting modes have spatial and polarization structures that depart greatly from the weak coupling form, and, in particular, are neither orbital nor spin angular momentum eigenstates. We explain the physical origins of this strong-coupling regime with a vector geometric theory of diffraction expansion.
EVOLUTION OF THE MERGER-INDUCED HYDROSTATIC MASS BIAS IN GALAXY CLUSTERS

In this work, we examine the effects of mergers on the hydrostatic mass estimate of galaxy clusters using high-resolution Eulerian cosmological simulations. We utilize merger trees to isolate the last merger for each cluster in our sample and follow the time evolution of the hydrostatic mass bias as the systems relax. We find that during a merger, a shock propagates outward from the parent cluster, resulting in an overestimate in the hydrostatic mass bias. After the merger, as a cluster relaxes, the bias in hydrostatic mass estimate decreases but remains at a level of ?5%-10% with 15%-20% scatter within r 500. We also investigate the post-merger evolution of the pressure support from bulk motions, a dominant cause of this residual mass bias. At r 500, the contribution from random motions peaks at 30% of the total pressure during the merger and quickly decays to ~10%-15% as a cluster relaxes. Additionally, we use a measure of the random motion pressure to correct the hydrostatic mass estimate. We discover that 4?Gyr after mergers, the direct effects of the merger event on the hydrostatic mass bias have become negligible. Thereafter, the mass bias is primarily due to residual bulk motions in the gas which are not accounted for in the hydrostatic equilibrium equation. We present a hydrostatic mass bias correction method that can recover the unbiased cluster mass for relaxed clusters with 9% scatter at r 500 and 11% scatter in the outskirts, within r 200.
Surface Brightness of Starbursts at Low and High Redshifts

Observations in the rest-frame ultraviolet from various space missions are used to define the nearby starburst regions having the highest surface brightness on scales of several hundred parsecs. The bright limit is found to be 6 × 10-16 ergs cm-2 s-1 A-1 arcsec-2 for rest-frame wavelength of 1830 A. Surface brightness in the brightest pixel is measured for 18 galaxies in the Hubble Deep Field having z > 2.2. After correcting for cosmological dimming, we find that the high-redshift starbursts have intrinsic ultraviolet surface brightness that is typically 4 times brighter than low-redshift starbursts. It is not possible to conclude whether this difference is caused by decreased dust obscuration in the high-redshift starburst regions or by intrinsically more intense star formation. Surface brightness enhancement of starburst regions may be the primary factor for explaining the observed increase with redshift of the ultraviolet luminosity arising from star formation.
Wind-Induced Magnetic Fluctuations

Irregular magnetic fluctuations, with time scales of the order 10 minutes to 2 or 3 hours, provide a characteristic feature of magnetograms at most latitudes during magnetic storms, and at high latitudes even at times of relatively low worldwide magnetic activity. Their amplitude is, of course, great at times of high activity, by definition, and decreases with decreasing activity. They have long been believed to yield a measure of the interaction between solar plasma and the geomagnetic field, and this belief has been firmly substantiated by recent observations of a close correlation between the magnetic Kp index and the speed of the solar wind [Snyder and Neugebauer, 1964]. It would be a natural extrapolation of this general viewpoint to invoke the same solar-wind source to explain the residual magnetic fluctuations, of amplitude 3-6 γ, say, that appear on most ‘quiet’ days even at middle latitudes. The present note is concerned with the possibility that a distinct second source is operative at this low level of intensity, however, and that this source provides a natural background of magnetic noise into which the fluctuations induced by the solar wind may subside on occasion. The source in question is that provided by the irregular winds of the ionospheric dynamo region.
Speaker, accent, and language identification using multilingual phone strings

In this paper we investigated the identification of non-verbal cues from spoken speech, namely speaker, accent, and language. For these tasks, a joint framework is developed which uses phone strings, derived from different language phone recognizers, as intermediate features and which performs classification decisions based on their perplexities. Our evaluation on variable distance data proved the robustness of the approach, achieving a 96.7% speaker identification rate. Furthermore, we achieved 93.7% accent discrimination accuracy between native and non-native speakers. For language identification, we obtained 95.5% classification accuracy for utterances 5 seconds in length and up to 99.89% on longer utterances. The experiments were carried out in a language independent nature, on languages not presented to the phone recognizers for training, suggesting that they could be successfully ported to non-verbal cue classification in other languages.
Accelerating D-branes.

Abstract Higher derivative terms are computed in the one-loop effective action governing the interactions of D3-branes, in two ways: (1) in a formalism with N =2 supersymmetry, and (2) in the standard background field formalism, with only on-shell supersymmetry. It is shown that these calculations only agree using tree-level equations of motion. The off-shell supersymmetric calculation exhibits acceleration terms that appear in terms with four derivatives. These may imply disagreement at two-loop order between supergravity and Yang-Mills descriptions of D-brane dynamics.
ON THE DEGENERACIES OF THE MASS-SQUARED DIFFERENCES FOR THREE-NEUTRINO OSCILLATIONS

Using an algebraic formulation, we explore two well-known degeneracies involving the mass-squared differences for three-neutrino oscillations assuming CP symmetry is conserved. For vacuum oscillation, we derive the expression for the mixing angles that permit invariance under the interchange of two mass-squared differences. This symmetry is most easily expressed in terms of an ascending mass order. This can be used to reduce the parameter space by one half in the absence of the MSW effect. For oscillations in matter, we derive within our formalism the known approximate degeneracy between the standard and inverted mass hierarchies in the limit of vanishing θ13. This is done with a mass ordering that permits the map Δ31↦-Δ31. Our techniques allow us to translate mixing angles in this mass order convention into their values for the ascending order convention. Using this dictionary, we demonstrate that the vacuum symmetry and the approximate symmetry invoked for oscillations in matter are distinctly different.
The effect of radiographic magnification on blood vessel imaging with various screen–film systems

From the computer simulation study of blood vessel imaging in cerebral angiography it is found that, with proper choice of the focal‐spot size and magnification ratio, radiographic magnification in conjunction with fast screens can give blood vessel images “equivalent” to or better than those from slower screens without magnification. However, this result is highly dependent on blood vessel diameter. If a sufficiently small focal spot is not available so that the proper choice of focal‐spot size and magnification cannot be made, then the vessel image from slower screens without magnification can be better than that from fast screens with magnification.
Cognitive and Behavioral Approaches in the Treatment of Obesity

Cognitive behavioral interventions have formed the cornerstone of obesity treatment for the past two decades. These techniques, often combined with diet and exercise strategies, have been shown to produce weight losses of sufficient magnitude so as to reduce health risks. Though success in producing short-term weight loss is improving, many factors, including a metabolic energy gap, continue to challenge long-term weight maintenance results. This article reviews the unique influence of cognitive, behavioral, and metabolic factors on weight loss and weight-loss maintenance, and how future treatment packages might be modified to improve longterm weight loss outcomes.
Deducing the Density Hales–Jewett Theorem from an Infinitary Removal Lemma

We offer a new proof of Furstenberg and Katznelson’s density version of the Hales–Jewett Theorem:
Strings on orientifolds

Abstract We construct several examples of compactification of type IIB theory on orientifolds and discuss their duals. In six dimensions we obtain models with N = 1 supersymmetry, multiple tensor multiplets, and different gauge groups. In nine dimensions we obtain a model that is dual to M-theory compactified on a Klein bottle.
Involvement of surface oxide films on iron in halide-induced pitting

Bromide-induced pitting of Fe is triggered by a critical state of the passive oxide film. The state corresponds to a specific thickness of the oxide which depends on the concentration of bromide ions, but not the anodizing potential. In addition, pitting will only occur if the critical state is established <10 s. The critical thickness for pitting is lineary dependent on the logarithm of the concentration of halide ions. Similar slopes are obtained for chloride and bromide ions, however the critical thickness for Br− is greater than for Cl− at the same concentration, reflecting the more aggressive nature of the Cl−. Once development of the passive film has passed the critical stage, pitting becomes very unlikely, even if the potential is held well above the pitting potential. Partial cathodic reduction experiments demonstrate that a thinner film does not pit more rapidly than a thicker film; instead more charge must pass for the thinner to reach the critical state prior to pitting.
Weak subintegral closure of ideals

We describe some basic facts about the weak subintegral closure of ideals in both the algebraic and complex-analytic settings. We focus on the analogy between results on the integral closure of ideals and modules and the weak subintegral closure of an ideal. We start by giving a new geometric interpretation of the Reid–Roberts–Singh criterion for when an element is weakly subintegral over a subring. We give new characterizations of the weak subintegral closure of an ideal. We associate with an ideal I of a ring A an ideal I>, which consists of all elements of A such that v(a)>v(I), for all Rees valuations v of I. The ideal I> plays an important role in conditions from stratification theory such as Whitney's condition A and Thom's condition Af and is contained in every reduction of I. We close with a valuative criterion for when an element is in the weak subintegral closure of an ideal. For this, we introduce a new closure operation for a pair of modules, which we call relative weak closure. We illustrate the usefulness of our valuative criterion.
Surface photochemistry of divalent metal alkyls on SiO2

Metal‐alkyl molecules adsorbed on chemically prepared silicon surfaces have been studied using infrared total‐internal reflection and ultraviolet transmission spectroscopies, temperature‐programmed desorption spectroscopy (TPD), and mass spectroscopy of laser induced desorption (LID) products. For chemisorbed species, the surface hydroxyl groups have been shown to be the prime adsorption sites. In addition, we determined the identity of the chemisorbed species and their fragments under ultraviolet photodissociation. Surface photodissociation was observed to be strongly wavelength dependent at 193 and 248 nm.
Descent of coherent sheaves and complexes to geometric invariant theory quotients

Abstract Fix a scheme X over a field of characteristic zero that is equipped with an action of a reductive algebraic group G. We give necessary and sufficient conditions for a G-equivariant coherent sheaf on X or a bounded-above complex of G-equivariant coherent sheaves on X to descend to a good quotient X G . This gives a description of the coherent derived category of X G as an admissible subcategory of the equivariant derived category of X.
Ekpyrotic and cyclic cosmology

Abstract Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes — and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w = P ρ ≫ 1 (where P is the average pressure and ρ the average energy density) during which the universe slowly contracts. This phase resolves the standard cosmological puzzles and generates a nearly scale-invariant spectrum of cosmological perturbations containing a significant non-Gaussian component. At the same time it produces small-amplitude gravitational waves with a blue spectrum. The dark energy dominating the present-day cosmological evolution is reinterpreted as a small attractive force between our brane and a parallel one. This force eventually induces a new ekpyrotic phase and a new brane collision, leading to the idea of a cyclic universe. This review discusses the detailed properties of these models, their embedding in M-theory and their viability, with an emphasis on open issues and observational signatures.
Stereoselective allylation for preparation of L-hexose derivatives

Abstract The reaction of allyltrimethylsilane with α,β-dialkoxyaldehydes is catalyzed by magnesium bromide, and provides for a highly stereoselective allylation which is predicted by α-chelation of the Lewis acid. The observed stereocontrol is opposite to that generally obtained from a variety of common allylation reagents.
A concentration inequality and a local law for the sum of two random matrices

Let \({H_{N}=A_{N}+U_{N}B_{N}U_{N}^{\ast}}\) where AN and BN are two N-by-N Hermitian matrices and UN is a Haar-distributed random unitary matrix, and let \({\mu _{H_{N}},}\)\({\mu_{A_{N}}, \mu _{B_{N}}}\) be empirical measures of eigenvalues of matrices HN, AN, and BN, respectively. Then, it is known (see Pastur and Vasilchuk in Commun Math Phys 214:249–286, 2000) that for large N, the measure \({\mu _{H_{N}}}\) is close to the free convolution of measures \({\mu _{A_{N}}}\) and \({\mu _{B_{N}}}\) , where the free convolution is a non-linear operation on probability measures. The large deviations of the cumulative distribution function of \({\mu _{H_{N}}}\) from its expectation have been studied by Chatterjee (J Funct Anal 245:379–389, 2007). In this paper we improve Chatterjee’s concentration inequality and show that it holds with the rate which is quadratic in N. In addition, we prove a local law for eigenvalues of \({H_{N_{N}},}\) by showing that the normalized number of eigenvalues in an interval approaches the density of the free convolution of μ A and μ B provided that the interval has width (log N)−1/2.
Can we interpret Kant as a compatibilist about determinism and moral responsibility

(2004). Can We Interpret Kant as a Compatibilist About Determinism and Moral Responsibility? British Journal for the History of Philosophy: Vol. 12, No. 4, pp. 719-730.
A Thermal graviton background from extra dimensions

Inflationary cosmology predicts a low-amplitude graviton background across a wide range of frequencies. This Letter shows that if one or more extra dimensions exist, the graviton background may have a thermal spectrum instead, dependent on the fundamental scale of the extra dimensions. The energy density is shown to be significant enough that it can affect nucleosynthesis in a substantial way. The possibility of direct detection of a thermal graviton background using the 21-cm hydrogen line is discussed. Alternative explanations for the creation of a thermal graviton background are also examined.
Drug-personality interaction in the learning of a nonsense syllable task

Summary.-DiMascio, et 01. have demonstrated that drugs produce differential effects in two personality types. The effects of three drugs (chlorpromazine, trifluoperazine, and secobarbital) on learning (nonsense syllables) were examined in individuals pre-selected according to the criteria set forth by DiMascio, et al. Drugs improved learning in one personality type only. The importance of drug-persona:icy interaction in psychopharmacologic studies is stressed. This report presents data on the learning of a nonsense syllable task by human Ss, of two contrasting personality types, after ingestion of three psychotropic drugs. These two personality types are those delineated by Klerman and DiMascio and in whom it was noted that drugs react differentially (Klerman, DiMascio, Greenblatt, & Rinkel, 1959). One type (Type A) was composed of extroverted, athletically oriented individuals, the other (Type B) of inuospective, intelleccually oriented individuals. Eight Type As and 8 Type Bs were tested under each of eight drug conditions: chlorpromazine (cpz), 100 and 200 mg.; trifluoperazine (tpz), 8 and 16 mg.; secobarbital (seco), 100 and 200 mg.; and placebos (twice). A doubleblind technique was used and drug administrations were rotated using a factorial design. At the time of peak <rug action, Ss were presented a list of 10 three-letter consonant nonsense syllables. Afcer presentation of the syllables, a I-min. task (simple addition) was interposed before Ss were asked to recall correctly as many of the syllables as possible. Eight equivalent lists of nonsense syllables had been constcucted by equating 1is:s for both association value and log frequency value. Each S was tested once on each list and the order of administration of lists was counterbalanced among drug conditions. Two measures of learning (recall ability) were the number of nonsense syllables attempted and [he per cent of these recalled correctly. Afcer placebo there was essentially no difference between the two personalicy types. When Ss were considered as one group, the only significant drug effects noted were a decrement in the number attempted after 200 mg. seco and an increment in number attempted after 8 mg. tpz. None of the drugs appeared to alter accuracy. When the data were cnalyzed separately for the two types, the As showed 'From the Psychopharmacolog~ Research Project of Massachusens Mental Health Center, 74 Fenwood Road, Boston, hlassachussetrs. Criteria for the two personality types are available from the authors.
Efficient organocatalytic α-sulfenylation of substituted piperazine-2,5-diones

Organocatalytic alpha-sulfenylation of substituted piperazine-2,5-diones is reported through the use of cinchona alkaloids as Lewis bases and electrophilic sulfur transfer reagents. 1-Phenylsulfanyl[1,2,4]triazole, a novel sulfur transfer reagent, gave excellent product yields with a number of substituted piperazine-2,5-diones under mild conditions. Catalyst loading, stoichiometry of sulfur electrophile, temperature and solvent were optimized to achieve high product yields.
New low-dimensional zinc compounds containing zinc-oxygen-phosphorus frameworks: two-layered inorganic phosphites and a polymeric organic phosphinate

The new zinc phosphites (IVa) ( P21/n, Z=4) and (IVb) (P1, Z=2), prepared according to the scheme (yields not given), have layered structures in which the Zn atoms are tetrahedrally coordinated and the alkaline-earth-metal atoms show eight-fold coordination.
Wolff's Problem of Ideals in the Multiplier Algebra on Dirichlet space

We establish an analogue of Wolff’s theorem on ideals in \(H^{\infty }(\mathbb {D})\) for the multiplier algebra of Dirichlet space.
Biomixing by chemotaxis and efficiency of biological reactions: The critical reaction case

Many phenomena in biology involve both reactions and chemotaxis. These processes can clearly influence each other, and chemotaxis can play an important role in sustaining and speeding up the reaction. In continuation of our work [A. Kiselev and L. Ryzhik, “Biomixing by chemotaxis and enhancement of biological reactions,” Comm. Partial Differential Equations 37, 298–318 (2012)]10.1080/03605302.2011.589879, we consider a model with a single density function involving diffusion, advection, chemotaxis, and absorbing reaction. The model is motivated, in particular, by the studies of coral broadcast spawning, where experimental observations of the efficiency of fertilization rates significantly exceed the data obtained from numerical models that do not take chemotaxis (attraction of sperm gametes by a chemical secreted by egg gametes) into account. We consider the case of the weakly coupled quadratic reaction term, which is the most natural from the biological point of view and was left open in Kiselev and Ryzh...
Self-Preserving Mixing Properties of Steady Round Buoyant Turbulent Plumes in Uniform Crossflows

The self-preserving mixing properties of steady round buoyant turbulent plumes in uniform crossflows were investigated experimentally. The experiments involved salt water sources injected into fresh water crossflows within the windowed test section of a water channel. Mean and fluctuating concentrations of source fluid were measured over cross sections of the flow using planar-laser-induced fluorescence which involved seeding the source fluid with Rhodamine 6G dye and adding small concentrations of ethanol to the crossflowing fluid in order to match the refractive indices of the source flow and the crossflow. The self-preserving penetration properties of the flow were correlated successfully based on the scaling analysis of Diez, Bernal, and Faeth (2003, ASME J. Heat Transfer, 125, pp. 1046-1057) whereas the self-preserving structure properties of the flow were correlated successfully based on the scaling analysis of Fischer et al. (1979, Mixing in Inland and Coastal Waters, Academic Press, New York, pp. 315-389); both approaches involved assumptions of no-slip convection in the cross stream (horizontal) direction (parallel to the crossflow) and a self-preserving line thermal having a conserved source specific buoyancy flux per unit length that moves in the streamwise (vertical) direction (parallel to the direction of both the initial source flow and the gravity vector). The resulting self-preserving structure consisted of two counter-rotating vortices having their axes nearly aligned with the crossflow direction that move away from the source in the streamwise (vertical) direction due to the action of buoyancy. Present measurements extended up to 202 and 620 source diameters from the source in the streamwise and cross stream directions, respectively. The onset of self-preserving behavior required that the axes of the counter-rotating vortex system be nearly aligned with the crossflow direction. This alignment, in turn, was a strong function of the source/crossflow velocity ratio, u o /v ∞ . The net result was that the onset of self-preserving behavior was observed at streamwise distances of 10-20 source diameters from the source for u o /v ∞ =4 (the smallest value of u o /v ∞ considered), increasing to streamwise distances of 160-170 source diameters from the source for u o /v ∞ =100 (the largest value of u o /v ∞ considered). Finally, the counter-rotating vortex system was responsible for substantial increases in the rate of mixing of the source fluid with the ambient fluid compared to axisymmetric round buoyant turbulent plumes in still environments, e.g., transverse dimensions in the presence of the self-preserving counter-rotating vortex system were 2-3 times larger than the transverse dimensions of self-preserving axisymmetric plumes at similar streamwise distances from the source.
The Discovery of Infrared Rings in the Planetary Nebula NGC 1514 During the WISE All-Sky Survey

We report the discovery of a pair of infrared, axisymmetric rings in the planetary nebula NGC 1514 during the course of the WISE all-sky mid-infrared survey. Similar structures are seen at visible wavelengths in objects such as the “Engraved Hourglass Nebula” (MyCn 18) and the “Southern Crab Nebula” (Hen 2-104). However, in NGC 1514 we see only a single pair of rings and they are easily observed only in the mid-infrared. These rings are roughly 0.2 pc in diameter, are separated by 0.05 pc, and are dominated by dust emission with a characteristic temperature of 160 K. We compare the morphology and color of the rings to the other nebular structures seen at visible, far-infrared, and radio wavelengths, and close with a discussion of a physical model and formation scenario for NGC 1514.
Housing tenure and labor market impacts: The search goes on

Abstract We develop two search-theoretic models emphasizing firm entry to examine the Oswald hypothesis, the idea that homeownership is linked to inferior labor market outcomes, and compare their predictions to three extant theories. The five models have surprisingly different predictions about the labor market at both the aggregate and micro levels. Using a suitable instrumental variable strategy, we estimate both micro and aggregate level regression models of wages and unemployment and compare the estimates to those predictions. We find that while homeowners are less likely to be unemployed, they also have lower wages, all else equal, compared to renters. In addition, higher regional homeownership rates are associated with a greater probability of individual worker unemployment and higher wages. The outcome of a horserace between our new search-theoretic models is mixed—the wage-posting model predicts observed unemployment impacts while a bargaining variant does a better job explaining observed wages and aggregate labor market outcomes. Overall, we conclude that firm behavior is important for understanding the labor market impacts of homeownership. Because this is the case, regional homeownership rates are not good instruments for individual tenure choice in empirical work. And while individual homeowners may have inferior labor market outcomes as compared to renters, from the viewpoint of society, higher homeownership rates may result in greater job creation and overall production, among other benefits.
Property rights and the political organization of agriculture

We propose a general equilibrium model where the economic organization of agriculture and the political equilibrium determining the security of property rights are jointly determined. In particular, because the form of organization may affect the probability and distribution of benefits from future property challenges, it may be shaped in anticipation of this impact. Property rights security may then be secured at the expense of economic efficiency. The model provides a framework for understanding why in some contexts land is redistributed primarily via land sales and tenancy markets but via politics and conflict in others. We test some implications of the theory using a five-decade panel dataset that traces changes in the extent of tenancy and tenancy reform across 15 Indian states.
What technical and scientific communicators do: A comprehensive model for developing academic programs

A growing number of colleges and universities are preparing programs to educate students for careers as technical and scientific communicators. The educators who design these new programs have three major resources to help them determine what their program should look like: descriptions of existing programs; published articles that discuss program design in a general way; and advice from practicing professionals. These resources do not provide a satisfactory basis for designing programs. A more satisfactory resource is a model of what the profession does. This model consists of (1) a definition of the common professional aim of all practicing technical and scientific communicators, (2) an abstract, and idealized, description of the general activities that practicing communicators perform as they pursue that aim, and (3) a catalog of the major features of the contexts within which these communicators pursue their common aim. The model is presented and its application to program design is illustrated.
Spontaneous Relaxation in Generalized Oscillator Models with Glassy Dynamics

In this paper we introduce the generalized oscillator model (GOM) as a family of exactly solvable models useful to investigate theoretical aspects related to the statistical description of the aging state. GOMs are defined by a potential function V(x) and characterized by a zero-temperature relaxation determined by entropy barriers and partial equilibration. Analytic expressions for the effective temperature can be derived using a fluctuation theorem valid in the aging regime without the need to solve the dynamical equations for correlations and responses. Two classes of models are investigated in detail: the homogeneous potential model with V(x) = (k/2p)x2p (p being a positive integer) and the wedge potential model (V(x) = k|x| where V(x) has a singularity at the ground-state coordinate x = 0). For the latter, we present some numerical simulations that reinforce the validity of the main analytical results. GOMs offer a conceptual framework to develop a statistical description of the spontaneous relaxati...
Bifurcation Control of Nonlinear Systems With Time-Periodic Coefficients

In this study, a method for the nonlinear bifurcation control of systems with periodic coefficients is presented. The aim of bifurcation control is to stabilize post bifurcation limit sets or modify other nonlinear characteristics such as stability, amplitude or rate of growth by employing purely nonlinear feedback controllers. The method is based on an application of the Lyapunov-Floquet transformation that converts periodic systems into equivalent forms with time-invariant linear parts. Then, through applications of time-periodic center manifold reduction and time-dependent normal form theory completely time-invariant nonlinear equations are obtained for codimension one bifurcations. The appropriate control gains are chosen in the time-invariant domain and transformed back to the original variables. The control strategy is illustrated through the examples of a parametrically excited simple pendulum undergoing symmetry-breaking bifurcation and a double inverted pendulum subjected to a periodic load in the case of a secondary Hopf bifurcation.
Ultra-High-Energy Cosmic Rays from Young Neutron Star Winds.

The long-held notion that the highest energy cosmic rays are of distant extragalactic origin is challenged by observations that events above ~1020 eV do not exhibit the expected high-energy cutoff from photopion production off the cosmic microwave background. We suggest that these unexpected ultra-high-energy events are due to iron nuclei accelerated from young strongly magnetized neutron stars through relativistic MHD winds. We find that neutron stars whose initial spin periods are shorter than ~10 ms and whose surface magnetic fields are in the 1012-1014 G range can accelerate iron cosmic rays to greater than ~1020 eV. These ions can pass through the remnant of the supernova explosion that produced the neutron star without suffering significant spallation reactions or energy loss. For plausible models of the Galactic magnetic field, the trajectories of the iron ions curve sufficiently to be consistent with the observed, largely isotropic arrival directions of the highest energy events.
Wide QRS Tachycardia: What Is the Rhythm?

We report a case of an elderly man who presented to the emergency room complaining of palpitations. Electrocardiogram revealed wide QRS tachycardia with a narrow beat within the tachycardia. Most commonly, a narrow complex beat during a wide complex tachycardia suggests a capture or fusion beat in the setting of ventricular tachycardia. However, there are situations where supraventricular tachycardia can also manifest this way. In our patient a pacemaker interrogation clarified the diagnosis.
Supervision Ethics: Counseling the Supervisee

Certain, but not all, models of supervision, whetherformarriage and family therapy orfor individually based counseling, have counseling the supervisee as a legitimate component of supervision. There are differing views on the boundary issues associated with allowing the supervision session to begin with a focus on the skills of the counselor and then to become therapeutically focused on the supervisee. This issue suggests thatsupervision training should consider the limits of counseling within the supervision process. Yet, many supervisors rely on skills from their therapy training as models for the supervision process. In this column, an example of a supervisee's personal difficulties arises within supervision, which cause significant changes for both supervisor and supervisee.
First total synthesis of sialylated and sulfated Lewisx mucin Core 2 structures as potential tumor associated antigens

Abstract Two branched Core 2 structures, (3-O-SO3Na)Galβ1→4(Fucα1→3)GlcNAcβ1→6(NeuAcα2→3Galβ1→3)GalNAcαOMe (1) and its positional isomer NeuAcα2→3Galβ1→4(Fucα1→3)GlcNAcβ1→6(3-OSO3Na-Galβ1→3)GalNAcαOMe (2), were chemically synthesized for the first time as potential tumor associated antigens.
Preparation of Organometallic Compounds from Highly Reactive Metal Powders

The formation of novel organometallic compounds by the reaction of organic substrates with finely divided metal powders represents a powerful tool for the synthetic chemist. The direct reaction with a zerovalent metal is the only viable method of synthesis for many of these compounds. Accordingly, chemists have been actively developing new methods for increasing the reactivity of metal powders toward organic substrates. Three principal approaches have been developed in recent years: the metal vaporization method, sonochemistry, and the preparation of finely divided metal powders by the reduction of metal salts. A number of new methods of synthesis have resulted from these studies.
Selective Reduction of Carboxylic Acid Esters in the Presence of a Five-Membered Cyclic Sulfone

Abstract Carboxylic acid esters can be selectively reduced in the presence of five-membered cyclic sulfones using AlH3. ether in anhydrous THF at cold temperatures.
Personality and performance: A comparative analysis of workers in transition economies

We use data collected from employees in five transition economies to study whether locus of control and preference for challenge versus affiliation are positively related to worker performance. We find that earnings are positively related to the internal locus of control and preference for challenge among participants of the Armenian and Serbian surveys. In the Russian sample, earnings tend to be higher among workers with a more internal locus of control. Earnings are not systematically related to personality in Kazakhstan and Kyrgyzstan. For most countries, self-reported performance tends to be significantly higher among workers with preference for challenge. Generally, the size of the personality effect on performance is at least as great as the effect of experience or education. Although more research needs to be done before final conclusions about the causes of cross-country differences can be made, we argue that variation in personality effects across countries may be influenced by level of economic development, degree of market-orientation, and cultural diversity.
Propagation of normal zones in composite superconductors

Abstract This paper describes calculations of propagation velocities of normal zones in composite superconductors. Full account is taken of (1) current sharing, (2) the variation with temperature of the thermal conductivity of the copper matrix, and the specific heats of the matrix and the superconductor, and (3) the variation with temperature of the steady-state heat transfer at a copper-helium interface in the nucleate-boiling, transition, and film-boiling ranges. The theory, which contains no adjustable parameters, is compared with experiments on bare (uninsulated) conductors. Agreement is not good. It is concluded that the effects of transient heat transfer may need to be included in the theory to improve agreement with experiment.
Fallback and Black Hole Production in Massive Stars

The compact remnants of core-collapse supernovae?neutron stars and black holes?have properties that reflect both the structure of their stellar progenitors and the physics of the explosion. In particular, the masses of these remnants are sensitive to the density structure of the presupernova star and to the explosion energy. To a considerable extent, the final mass is determined by the fallback, during the explosion, of matter that initially moves outward, yet ultimately fails to escape. We consider here the simulated explosion of a large number of massive stars (9-100 M?) of Population I (solar metallicity) and III (zero metallicity) and find systematic differences in the remnant mass distributions. As pointed out by Chevalier, supernovae in more compact progenitor stars have stronger reverse shocks and experience more fallback. For Population III stars above about 25 M? and explosion energies less than -->1.5 ? 1051 ergs, black holes are a common outcome, with masses that increase with increasing main-sequence mass up to a maximum hole mass, for very low explosion energy, of about 40 M?. If such stars produce primary nitrogen, however, their black holes are systematically smaller. For modern supernovae with nearly solar metallicity, black hole production is much less frequent and the typical masses, which depend sensitively on explosion energy, are smaller. The maximum black hole mass is about 15 M?. We explore the neutron star initial mass function for both populations and, for reasonable assumptions about the initial mass cut of the explosion, find good agreement with the average of observed masses of neutron stars in binaries. We also find evidence for a bimodal distribution of neutron star masses with a spike around 1.2 M? (gravitational mass) and a broader distribution peaked around 1.4 M?.
A Search for Active Galactic Nuclei in Sc Galaxies with H II Spectra

We have searched for nuclear radio emission from a statistically complete sample of 40 Sc galaxies within 30 Mpc that are optically classified as star-forming objects, in order to determine whether weak active galactic nuclei might be present. Only three nuclear radio sources were detected, in NGC 864, NGC 4123, and NGC 4535. These galaxies have peak 6 cm radio powers of ~1020 W Hz-1 at arcsecond resolution, while upper limits of the nondetected galaxies typically range from 1018.4 to 1020 W Hz-1. The three nuclear radio sources are all resolved and appear to have diffuse morphologies, with linear sizes of ~300 pc. This strongly indicates that circumnuclear star formation has been detected in these three H II galaxies. Comparisons with previous 20 cm Very Large Array (VLA) results for the detected galaxies show that the extended nuclear radio emission has a flat spectrum in two objects and is almost certainly generated by thermal emission from gas ionized by young stars in the centers of those galaxies. The 6 cm radio powers are comparable to predictions for thermal emission that are based on the nuclear Hα luminosities and imply nuclear star formation rates of 0.08-0.8 M☉ yr-1, while the low-resolution NRAO VLA Sky Survey implies galaxy-wide star formation rates of 0.3-1.0 M☉ yr-1 in stars above 5 M☉. In a few of the undetected galaxies, the upper limits to the radio power are lower than predicted from the Hα luminosity, possibly because of overresolution of central star-forming regions. Although the presence of active nuclei powered by massive black holes cannot be definitively ruled out, the present results suggest that they are likely to be rare in these late-type galaxies with H II spectra.