cssi/SciSciGPT-SciSciNet huggingface dataset:
Venus atmospheric circulation: Known and unknown

[1] After a pause of more than two decades, Venus' atmosphere is being explored again. Since April 2006, European Space Agency's Venus Express has been acquiring data, exploiting the near-infrared windows that allow us to peer into the deep night-side atmosphere. In June 2007, NASA's MESSENGER mission will fly past Venus on its way to Mercury, collecting useful data for a few weeks. Instruments and experiments on Venus Express are expected to provide a more comprehensive set of atmospheric observations over three and perhaps more Venus days. Venus Express observations are already providing clues about the processes that maintain the rapid circulation of Venus' atmosphere. The early observations show not only that the global circulation is organized into two hemispheric vortices centered over respective poles, but also that the vortex organization extends deep into the atmosphere. The limited Galileo NIMS near-infrared observations in 1989 had revealed the deep circulation in the equatorial regions, but because of the spacecraft, flyby trajectory could not observe the high latitudes to elucidate the polar circulation and its organization. The long hiatus in systematic Venus observations has provided an opportunity to perform some new analysis of the previous Pioneer Venus observations. This paper presents a synopsis of the circulation measurements at high latitudes and an analysis of the solar thermal tides seen in the cloud motions and suggests some limitations of previous estimates of transport of angular momentum by eddies.
Mixing Times for Random Walks on Finite Lamplighter Groups

Given a finite graph $G$, a vertex of the lamplighter graph $G^\diamondsuit=\mathbb {Z}_2 \wr G$ consists of a zero-one labeling of the vertices of $G$, and a marked vertex of $G$. For transitive $G$ we show that, up to constants, the relaxation time for simple random walk in $G^\diamondsuit$ is the maximal hitting time for simple random walk in $G$, while the mixing time in total variation on $G^\diamondsuit$ is the expected cover time on $G$. The mixing time in the uniform metric on $G^\diamondsuit$ admits a sharp threshold, and equals $|G|$ multiplied by the relaxation time on $G$, up to a factor of $\log |G|$. For $\mathbb {Z}_2 \wr \mathbb {Z}_n^2$, the lamplighter group over the discrete two dimensional torus, the relaxation time is of order $n^2 \log n$, the total variation mixing time is of order $n^2 \log^2 n$, and the uniform mixing time is of order $n^4$. For $\mathbb {Z}_2 \wr \mathbb {Z}_n^d$ when $d\geq 3$, the relaxation time is of order $n^d$, the total variation mixing time is of order $n^d \log n$, and the uniform mixing time is of order $n^{d+2}$. In particular, these three quantities are of different orders of magnitude.
A discussion of `Assessing the relative informativeness and permanence of pro forma earnings and GAAP operating earnings¿

Abstract By analyzing a carefully constructed earnings announcements sample that discloses a ‘pro forma’ earnings number, Bhattacharya et al. (J. Account. Econom. 36 (1–3) (2003)) contribute to recent research documenting increasing differences between earnings as defined by generally accepted accounting principles (GAAP) and alternative earnings definitions followed by capital markets. The paper provides interesting descriptive data on pro forma earnings per share relative to both GAAP earnings per share and actual earnings per share as tracked by I/B/E/S. Also, the authors conduct tests of the relative informativeness and persistence of these three earnings measures. Econometric and data limitations inhibit the inferences that can be drawn from some of these tests.
The impact of central lung distance, maximal heart distance, and radiation technique on the volumetric dose of the lung and heart for intact breast radiation.

Abstract Purpose : To investigate the impact of radiographic parameter and radiation technique on the volumetric dose of lung and heart for intact breast radiation. Methods and Materials : Forty patients with both two-dimensional (2D) and computed tomographic (CT) simulations were enrolled in the study. Central lung distance (CLD), maximal heart distance (MHD), and maximal heart length (MHL) were measured under virtual simulation. Four plans were compared for each patient. Plan A used a traditional 2D tangential setup. Plan B used clinical target volume (CTV) based three-dimensional (3D) planning. Both plans C and D used a combination of a medial breast field with shallow tangents. Plan D is a further modification of plan C. Results : Under the traditional tangential setup, the mean ipsilateral lung dose and volume at 20, 30, and 40 Gy correlated linearly with CLD (R = 0.85∼0.91). The mean ipsilateral lung dose (Gy) approximated 4 times the CLD value (cm), whereas the percentage volume (%) of ipsilateral lung at 20, 30, and 40 Gy was about 10 times the CLD (cm). The mean heart dose and percentage volume at 20, 30, and 40 Gy correlated with MHD (R = 0.76∼0.80) and MHL (R = 0.65∼0.75). The mean heart dose (Gy) approximated 3 times the MHD value (cm), and the percentage volume (%) of the heart at 10, 20, 30, and 40 Gy was about 6 times MHD (cm). Radiation technique impacted lung and heart dose. The 3D tangential plan (plan B) failed to reduce the volumetric dose of lung and heart from that of the 2D plan (plan A). The medial breast techniques (plans C and D) significantly decreased the volume of lung and heart receiving high doses (30 and 40 Gy). Plan D further decreased the 20 Gy volumes. By use of the medial breast technique, the lung and heart dose were not impacted by original CLD and MHD/MHL. Therefore, the improvement from the tangential technique was more remarkable for patients with CLD ≥ 3.0 cm (p Conclusions : The CLD and MHD impact the volumetric dose of lung and heart. The application of 3D planning for tangential breast irradiation does not decrease heart and lung dose. Adding a medial breast port significantly decreases percentage volume (PV) of lung and heart receiving high doses, especially when the CLD is excessive.
The dynamic variable input-output model: An advancement from the Leontief dynamic input-output model

The Dynamic Variable Input-Output (VIO) model extends the static single regional version of the Multiregional Variable Input-Output (MRVIO) model which is a general equilibrium model applied to the Leontief Input-Output model. The Dynamic VIO model which incorporates time dimensions can describe the real situation more accurately while maintaining the computational simplicity. Under the model, the investment expenditures are directly linked with the profit maximizing behavior of firms. Both technical coefficients and capital stock requirement coefficients include price terms, and they become variable instead of being fixed.
Long-Term Continuous Monitoring of the Broad-Line Radio Galaxies 3C 390.3 and 3C 120 with the Rossi X-Ray Timing Explorer

We present a study of the flux and spectral variability of the two broad-line radio galaxies (BLRGs) 3C 390.3 and 3C 120, observed almost daily with the Rossi X-Ray Timing Explorer for nearly 2 months each in 1996 and 1997, respectively. Our original motivation for this study was to search for systematic differences between BLRGs and their radio-quiet counterparts, the Seyfert galaxies, whose temporal and spectral behavior is better studied. We find that both 3C 390.3 and 3C 120 are highly variable but in different ways, and we quantify this difference by means of a structure function analysis. 3C 390.3 is significantly more variable than 3C 120, despite its jet's larger inclination angle, implying either that the X-ray variability is not dominated by the jet or that two different variability processes are simultaneously at work in 3C 390.3. We perform an energy-selected and time-resolved analysis based on the fractional variability amplitude and find that the variability amplitude of both objects is strongly anticorrelated with the energy. This last result, along with the correlated change of the photon index with the X-ray continuum flux, can be qualitatively explained within the scenario of thermal Comptonization, generally invoked for radio-quiet active galaxies. Moreover, the time-resolved and energy-selected fractional variability analysis shows a trend opposite to that observed in jet-dominated active galactic nuclei (blazars), suggesting only a minor contribution of the jet to the X-ray properties of BLRGs. Time-averaged spectral analysis indicates the presence of a strong resolved Fe Kα line with a centroid at 6.4 keV and a weak (Ω/2π 0.1-0.4) reflection component in both objects. The overall PCA+HEXTE spectra are best fitted with the constant density ionization model of Ross & Fabian, but with a modest ionization parameter. We perform a time-resolved spectral analysis of 3C 390.3 with the aim of constraining the delay between Fe Kα line and continuum variability; however, the limited signal-to-noise ratio of the line flux hampers a thorough study of the line variability.
Antimalarial bromophycolides J-Q from the Fijian red alga Callophycus serratus.

Bromophycolides J−Q (1−8) were isolated from extracts of the Fijian red alga Callophycus serratus and identified with 1D and 2D NMR spectroscopy and mass spectral analyses. These diterpene−benzoate macrolides represent two novel carbon skeletons and add to the 10 previously reported bromophycolides (9−18) from this alga. Among these 18 bromophycolides, several exhibited activities in the low micromolar range against the human malaria parasite Plasmodium falciparum.
An efficient synthesis of functionalized urethanes from azides

Catalytic hydrogenation of various azides in the presence of functionalized mixed carbonates afforded the corresponding urethanes in high yields.
N-Halosuccinimide/BF3−H2O, Efficient Electrophilic Halogenating Systems for Aromatics

N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF(3)-H(2)O, allowing the halogenations of deactivated aromatics. Because BF(3)-H(2)O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H(0) approximately 12, only slightly lower than that of trifluoromethanesulfonic acid), an efficient new electrophilic reagent combination of NXS/BF(3)-H(2)O has been developed. DFT calculations at the B3LYP/6-311++G//B3LYP/6-31G level suggest that protonated N-halosuccinimides undergo further protosolvation at higher acidities to reactive superelectrophilic species capable either in the transfer of X(+) from the protonated forms of NXS to the aromatic substrate or in forming a highly reactive and solvated X(+) which would readily react with the aromatic substrates. Structural aspects of the BF(3)-H(2)O complex have also been investigated.
Anarchy, Groups, and Conflict: An Experiment on the Emergence of Protective Associations

In this article, we investigate the implications of the philosophical considerations presented in Nozick’s Anarchy, State, and Utopia, by examining group formation in a laboratory setting where subjects engage in both cooperative and conflictual interactions. We endow participants with a commodity used to generate earnings, plunder others, or protect against plunder. In our primary treatment, we allow participants to form groups to pool their resources. We conduct a baseline comparison treatment that does not allow group formation. We find that allowing subjects to organize themselves into groups does not lead to more cooperation and may in fact exacerbate tendencies towards conflict.
IMPROVING LLR TESTS OF GRAVITATIONAL THEORY

We are exploring the modeling improvements necessary to proceed from cm to mm range accuracies enabled by the new Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) currently under development.
Geologic results from the lunar precursor probes.

we need to use only one of the arbitrary terms (note that mo and UQ are not arbitrary), setting all other arbitrary terms equal to zero. The choice depends on the requirement that the coefficient of the power of IJL should be near but not much greater than unity. For a mixed boundary-value problem, there are six integrals of motion near the moon: h, I, i, 6, a*, and TQ + /XT; and six near the earth: he = — p, le = n\, i, co, 0, and TQ + fjLTi. Subject to the necessary constraints for a moon-to-earth trajectory, a specified combination of six of the integrals will determine the remaining six (but perhaps not uniquely nor to the same order of accuracy). In general, the method for finding the six unknown integrals involves the simultaneous solution of Eqs. (35-43), (56-58), (73), and (lla) of Ref. 3, subject to the conditions of Eqs. (20) and (22). Since each particular combination of the specified integrals requires a separate analysis, it is not possible to summarize the results as was done for the initial-value problem. References 1 Lagerstrom, P. A. and Kevorkian, J., "Earth-to-Moon Trajectories in the Restricted Three-Body Problem/' Journal de Mecanique, Vol. 2, 1963, pp. 189-218. 2 Lagerstrom, P. A. and Kevorkian, J., "Numerical Aspects of Uniformly Valid Asymptotic Approximations for a Class of Trajectories in the Restricted Three-Body Problem/ AIAA Progress in Aeronautics and Astronautics: Celestial Mechanics and Astrodynamics, edited by V. G. Szebehely, Vol. 14, Academic Press, New York, 1964, pp. 3-33. 3 Lagerstrom, P. A. and Kevorkian, J., "Nonplanar Earthto-Moon Trajectories in the Restricted Three-Body Problem/' AIAA Journal, Vol. 4, No. 1, Jan. 1966, pp. 149-152. 4 Kevorkian, J. and Lancaster, J. E., "An Asymptotic Solution for a Class of Periodic Orbits of the Restricted Three-body Problem/' Astronomical Journal (to be published). 5 Shi, Y. Y. and Eckstein, M. C., "Uniformly Valid Asymptotic Solution of Non-Planar Earth-to-Moon Trajectories in the Restricted Four-Body Problem," Astronomical Journal, Vol. 72, 1967, p. 685.
On Periodic Sequences for Algebraic Numbers

Abstract For each positive integer n ⩾2, a new approach to expressing real numbers as sequences of nonnegative integers is given. The n =2 case is equivalent to the standard continued fraction algorithm. For n =3, it reduces to a new iteration of the triangle. Cubic irrationals that are roots x 3 + kx 2 + x −1 are shown to be precisely those numbers with purely periodic expansions of period length one. For general positive integers n , it reduces to a new iteration of an n dimensional simplex.
Tidal disruption of solid bodies

The problem of stress, strain, and breakup in solid satellites and stray bodies subject to tidal perturbations is presently addressed in view of three novel considerations. After presenting a new analytic solution for the stress tensor in a homogeneous and compressible elastic sphere, where the inclusion of compressibility alters stresses by several percent, realistic failure criteria are noted to demonstrate the general failure of such ductile bodies as iron meteoroids by plastic shear, while brittle ice bodies fail by either tensile or shear fracture. A reexamination of crack propagation after initial failure allows the diverse breakup criteria to be reconciled.
Chromospheric Mass Motions and Intrinsic Sunspot Rotations for NOAA Active Regions 10484, 10486, and 10488 Using ISOON Data

This work utilizes Improved Solar Observing Optical Network continuum (630.2 nm) and Hα (656.2 nm) data to: (1) detect and measure intrinsic sunspot rotations occurring in the photosphere and chromosphere, (2) identify and measure chromospheric filament mass motions, and (3) assess any large-scale photospheric and chromospheric mass couplings. Significant results from 2003 October 27-29, using the techniques of Brown et al., indicate significant counter-rotation between the two large sunspots in NOAA AR 10486 on October 29, as well as discrete filament mass motions in NOAA AR 10484 on October 27 that appear to be associated with at least one C-class solar flare.
Zeolite-supported transition metal catalysts by design

Abstract Zeolite supported metal Catalysts are prepared by ion exchange or incipient wetness impregnation, or by deposition of metal complexes, followed by calcination and reduction. Hydrogen reduction of encaged transition metal ions yields metal dusters or isolated atoms and protons of high Bronsted acidity. The elementary steps in the genesis of mono- and bimetallic metal dusters have been unravelled by a combination of dynamic and spectroscopic methods. Small metal clusters can be anchored to zeolite cage walls by transition metal ions or protons; however, adsorption of a CO which can displace the protons from the metal, initiates migration of the primary carbonyl dusters leading to their coalescence. At low temperature, this process is limited by the geometry of the metal core vis-a-vis the cage window. Protons of high Brensted acidity can reoxidize metals at elevated temperature, even selectively “leach” the less noble metal atoms out of bimetal clusters. Large metal particles, present in zeolite voids or at the external surface, can be transformed into small particles, exposing virtually all their metal atoms, by either of two novel in situ techniques which are based on oxidative dispersion with oxygen or chlorine gas.
A more powerful test for comparing two Poisson means

The problem of hypothesis testing about two Poisson means is addressed. The usual conditional test (C-test) and a test based on estimated p-values (E-test) are considered. The exact properties of the tests are evaluated numerically. Numerical studies indicate that the E-test is almost exact because its size seldom exceeds the nominal level, and it is more powerful than the C-test. Power calculations for both tests are outlined. The test procedures are illustrated using two examples.
Neutrino-pair emission from hot nuclei during stellar collapse

We present shell-model calculations showing that residual interaction-induced configuration mixing enhances the rate of neutral current de-excitation of thermally excited nuclei into neutrino-antineutrino pairs. Though our calculations reinforce the conclusions of previous studies that this process is the dominant source of neutrino pairs near the onset of neutrino trapping during stellar collapse, our shell-model result has the effect of increasing the energy of these pairs, possibly altering their role in entropy transport in supernovae.
Some aspects of core formation in Mercury

Some questions dealing with the nature and history of a large metallic core within Mercury are considered. These include the existence of a core, its size, whether it is fluid or solid, the timescale for core formation, the geological consequences of core formation, and whether such consequences are consistent with the surface geology. Several indirect lines of evidence are discussed which suggest the presence of a large iron-rich core. A core-formation model is examined in which core infall is accompanied by an increase of 17 km in planetary radius, an increase of 700 K in mean internal temperature, and substantial melting of the mantle. It is argued that if the core differentiated from an originally homogeneous planet, that event must have predated the oldest geological units comprising most of the planetary surface. A convective dynamo model for the source of Mercury's magnetic field is shown to conflict with cosmochemical models that do not predict a substantial radiogenic heat source in the core.
Segregation in the Falicov-Kimball Model

The Falicov–Kimball model is a simple quantum lattice model that describes light and heavy electrons interacting with an on-site repulsion; alternatively, it is a model of itinerant electrons and fixed nuclei. It can be seen as a simplification of the Hubbard model; by neglecting the kinetic (hopping) energy of the spin up particles, one gets the Falicov–Kimball model. We show that away from half-filling, i.e. if the sum of the densities of both kinds of particles differs from 1, the particles segregate at zero temperature and for large enough repulsion. In the language of the Hubbard model, this means creating two regions with a positive and a negative magnetization. Our key mathematical results are lower and upper bounds for the sum of the lowest eigenvalues of the discrete Laplace operator in an arbitrary domain, with Dirichlet boundary conditions. The lower bound consists of a bulk term, independent of the shape of the domain, and of a term proportional to the boundary. Therefore, one lowers the kinetic energy of the itinerant particles by choosing a domain with a small boundary. For the Falicov- Kimball model, this corresponds to having a single “compact” domain that has no heavy particles.
Natural barriers to natural disasters: replanting mangroves after the tsunami

The Indian Ocean tsunami disaster of December 2004 has increased interest in replanting degraded and deforested mangrove areas in Asia to improve coastal protection. Evidence from Thailand suggests that concern over mangrove deforestation by shrimp farms is an important motivation for many coastal households to participate in mangrove rehabilitation. However, successful re-establishment and management of mangroves as effective coastal barriers will require developing new institutions and policies, and must involve coastal communities in Thailand and other Indian Ocean countries in the conservation and protection of their local mangrove forests.
Designed molecules that fold to mimic protein secondary structures

Molecules that fold to mimic protein secondary structures have emerged as important targets of bioorganic chemistry. Recently, a variety of compounds that mimic helices, turns, and sheets have been developed, with notable advances in the design of beta-peptides that mimic each of these structures. These compounds hold promise as a step toward synthetic molecules with protein-like properties and as drugs that block protein-protein interactions.
Simultaneously bound guests and chiral recognition: a chiral self-assembled supramolecular host encapsulates hydrophobic guests

Abstract Driven by the hydrophobic effect, a water-soluble, chiral, self-assembled supramolecular host is able to encapsulate hydrophobic organic guests in aqueous solution. Small aromatics can be encapsulated in the supramolecular assembly, and the simultaneous encapsulation of multiple species is observed in many cases. The molecular host assembly is able to recognize different substitutional isomers of disubstituted benzenes with ortho substitution leading to the encapsulation of two guests, but meta or para substitution leading to the encapsulation of only one guest. The scope of hydrophobic guest encapsulation is further explored with chiral natural products. Upon encapsulation of chiral molecules into the racemic host, diastereomeric host–guest complexes are formed with observed diastereoselectivities of up to 78:22 in the case of fenchone.
Abelian groups with a $p^2$-bounded subgroup, revisited

Let Λ be a commutative local uniserial ring of length n, p be a generator of the maximal ideal, and k be the radical factor field. The pairs (B, A) where B is a finitely generated Λ-module and A ⊆B a submodule of B such that pmA = 0 form the objects in the category $\mathcal S_m(\Lambda)$. We show that in case m = 2 the categories $\mathcal S_m(\Lambda)$ are in fact quite similar to each other: If also Δ is a commutative local uniserial ring of length n and with radical factor field k, then the categories $\mathcal S_2(\Lambda)/\mathcal N_\Lambda$ and $\mathcal S_2(\Delta)/\mathcal N_\Delta$ are equivalent for certain nilpotent categorical ideals $\mathcal N_\Lambda$ and $\mathcal N_\Delta$. As an application, we recover the known classification of all pairs (B, A) where B is a finitely generated abelian group and A ⊆ B a subgroup of B which is p2-bounded for a given prime number p.
Atomic Oxygen Treatment for Non-Contact Removal of Organic Protective Coatings from Painting Surfaces

Current techniques for removal of varnish (lacquer) and other organic protective coatingsfrom paintings involve contact with the surface. This contact can remove pigment, or alter the shape and location of paint on the canvas surface. A thermal energy atomic oxygen plasma, developed to simulate the space environment in low Earth orbit, easily removes these organic materials. Uniform removal of organic protective coatings from the surfaces ofpaintings is accomplished through chemical reaction. Atomic oxygen will not react with oxides so that most paint pigments will not be affected by the reaction. For paintings containing organic pigments, the exposure can be carefully timed so that the removal stops just short of the pigment. Color samples of Alizarin Crimson, Sap Green, and Zinc White coated with Damar lacquer were exposed to atomic oxygen. The lacquer was easily removed fromall of the samples. Additionally, no noticeable change in appearance was observed after the lacquer was reapplied. The same observations were made on a painted canvas test sampleobtained from the Cleveland Museum of Art. Scanning electron microscope photographs showed a slight microscopic texturing of the vehicle after exposure. However, there was no removal or disturbance of the paint pigment on the surface. It appears that noncontact cleaning using atomic oxygen may provide a viable alternative to other cleaning techniques. Itis especially attractive in cases where the organic protective surface cannot be acceptably or safely removed by conventional techniques.
Synthesis of Solid, Spherical Zirconia Particles by Spray Pyrolysis

A model is used to predict solid particle formation during spray pyrolysis by correlating droplet shrinkage before salt precipitation with its relative solution saturation. For the rapid drying conditions and droplet size of {approximately}10 {mu}m, which are characteristic of conventional spray pyrolysis, solid salt particles are formed when a droplet's initial relative solution saturation is {approximately}10{sup {minus} 2} and the precipitated salt is sufficiently permeable to permit evolution of the remaining solvent after precipitation. It is proposed that this concentration allows the drying droplet more time and a shorter diffusion distance in which to maintain chemical homogeneity before precipitation. Using these concepts it is demonstrated that zirconyl chloride (ZrOCl{sub 2} {center dot} 8H{sub 2}O) and zirconyl hydroxychloride (ZrO(OH)Cl) are excellent zirconium salts for solid zirconia particle synthesis by spray pyrolysis.
Enumeration Schemes and, more importantly, their automatic generation

The notion of Enumeration Scheme is introduced and applied to the problem of counting permutations with forbidden patterns. Most importantly, the process is completely automated in a software package, WILF, accompanying this article.
M-theory origin of mirror symmetry in three-dimensional gauge theories

We present M-theory compactifications on K3 × K3 with membranes near the An or Dn singularities of the K3 spaces. By realizing each of these compactifications in two different ways as type I′ models with 2- and 6-branes, we explain the three-dimensional duality between gauge theories recently found by Intriligator and Seiberg. We also find new pairs of dual gauge theories, which we briefly describe.
A new algorithm for proving global asymptotic stability of rational difference equations

Global asymptotic stability (GAS) of rational difference equations is an area of research that has been well studied. In contrast to the many current methods for proving GAS, we propose an algorithmic approach. The algorithm we summarize here employs the idea of contractions. Given a particular rational difference equation, defined by a function , we attempt to find a K value for which shrinks distances to the difference equation's equilibrium point. We state some general results that our algorithm has been able to prove, and also mention the implementation of our algorithm using Maple.
Absolute Vacuum Ultraviolet Oscillator Strengths in Co II and the Interstellar Cobalt Abundance

We report the first laboratory measurements of 10 absolute oscillator strengths (f-values) for vacuum ultraviolet lines of Co II. The oscillator strengths are measured with the High-Sensitivity Absorption Spectroscopy Experiment at the University of Wisconsin. The measurements serve as a test of theoretical work on Co II f-values and set an absolute scale for relative oscillator strengths from spectra taken with the Hubble Space Telescope. Observations of interstellar absorption in the direction of ρ Oph A result in the determination of the f-value for an additional line. The set of absolute f-values is used to derive the interstellar abundance of cobalt toward ρ Oph A and ζ Oph. Cobalt is found to be less severely depleted onto grains than earlier analyses based on available theoretical f-values suggested. As a consequence of this revision, the correspondence between depletion and condensation temperature is somewhat weakened.
Components of Pearson's Phi-Squared Distance Measure for the k-Sample Problem

Abstract A general approach to the k-sample problem for continuous random variables, based on a generalization of Pearson's classical φ2 measure, is presented. Tests are developed by considering an analysis of variance type of orthogonal decomposition of a distance measure for a k-population goodness-to-fit hypothesis. Estimates of some of these components are shown to provide test statistics for the hypothesis that the k-populations have a common distribution. Several classical parametric and nonparametric tests are found to be quadratic functions of these component estimates. In addition, a new class of test statistic is derived that possesses aspects of both parametric and nonparametric methods.
Efficient radiative transfer in dust grain mixtures

The influence of a dust grain mixture consisting of spherical dust grains with different radii and/or chemical composition on the resulting temperature structure and spectral energy distribution of a circumstellar shell is investigated. The comparison with the results based on an approximation of dust grain parameters representing the mean optical properties of the corresponding dust grain mixture reveal that (1) the temperature dispersion of a real dust grain mixture decreases substantially with increasing optical depth, converging toward the temperature distribution resulting from the approximation of mean dust grain parameters, and (2) the resulting spectral energy distributions do not differ by more than 10% if � 2 5 grain sizes are considered, which justifies the mean parameter approximation and the many results obtained under its assumption so far. Nevertheless, the dust grain temperature dispersion at the inner boundary of a dust shell may amount to 4100 K and therefore has to be considered in the correct simulation of, e.g., chemical networks. In order to study the additional influence of geometrical effects, a two-dimensional configuration—the HH 30 circumstellar disk—was considered, using model parameters from Cotera et al. and Wood et al. A drastic inversion of the large to small grain temperature distribution was found within the inner � 1 AU of the disk. Subject headings: circumstellar matter — methods: numerical — radiative transfer — scattering On-line material: color figure
A geometric identity for Pappus' theorem.

Abstract An expression in the exterior algebra of a Peano space yielding Pappus' theorem was originally given by Doubilet, Rota, and Stein [Doubilet, P., Rota, G.-C. & Stein, J. (1974) Stud. Appl. Math. 8, 185-216]. Motivated by an identity of Rota, I give an identity in a Grassmann-Cayley algebra of step 3, involving joins and meets alone, which expresses the theorem of Pappus.
Age and protection of the ischemic myocardium: Is alkaline cardioplegia appropriate?

Hypothermic alkaline pharmacologic cardioplegia used in pediatric cardiac surgery may be less than satisfactory despite its benefits in adults. We determined whether the pH (7.8) of standard St. Thomas' II cardioplegic solution contributes to inadequate protection of the ischemic immature heart and whether the effect is age-related. Modified hypothermic St. Thomas' II solution (pH range, 4.8 to 8.8) was compared with hypothermic bicarbonate buffer alone (pH 7.25) in protecting the ischemic immature (7 to 10 days old) and mature (12 months old) rabbit heart. Isolated hearts (n = 6 per group) were perfused with bicarbonate buffer, and aortic flow was measured before hypothermic (14 degrees C) ischemia (immature hearts: 4 hours; mature hearts: 3 hours). Hearts were reperfused, and enzyme leakage and recovery of function were measured. In the immature heart, a bell-shaped dose-response profile was observed for pH and recovery of aortic flow but not for postischemic creatine kinase leakage. Optimal recovery of aortic flow (98% +/- 3%) occurred at pH 6.8, which was greater than protection with hypothermia alone (82% +/- 4%; p < 0.05) and standard St. Thomas' II solution (72% +/- 2%; p < 0.05). In the mature heart, a bell-shaped dose-response curve existed for recovery of aortic flow and a U-shaped curve existed for creatine kinase leakage. Again, optimal recovery of aortic flow (84% +/- 5%), which was superior to that with standard St. Thomas' II solution (60% +/- 8%; p < 0.05), and minimal enzyme leakage also occurred at pH 6.8, as did the least enzyme leakage (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Mode propagation in nonuniform circular ducts with potential flow

A previously reported closed form solution is expanded to determine effects of isentropic mean flow on mode propagation in a slowly converging-diverging duct - a circular cosh duct. On the assumption of uniform steady fluid density, the mean flow increases the power transmission coefficient. The increase is directly related to the increase of the cutoff ratio at the duct throat. With the negligible transverse gradients of the steady fluid variables, the conversion from one mode to another is negligible, and the power transmission coefficient remains unchanged with the mean flow direction reversed. With a proper choice of frequency parameter, many different modes can be made subject to a single value of the power transmission loss. The paper also describes a systematic method to include the effects of the gradients of the steady fluid variables.
Deghosting based on in-loop selective filtering using motion vector information for low-bit-rate-video coding

In this paper, a technique is presented to alleviate ghosting artifacts in the decoded video sequences for low-bit-rate video coding. Ghosting artifacts can be defined as the appearance of ghost like outlines of an object in a decoded video frame. Ghosting artifacts result from the use of a prediction loop in the video codec, which is typically used to increase the coding efficiency of the video sequence. They appear in the presence of significant frame-to-frame motion in the video sequence, and are typically visible for several frames until they eventually die out or an intra-frame refresh occurs. Ghosting artifacts are particularly annoying at low bit rates since the extreme loss of information tends to accentuate their appearance. To mitigate this effect, a procedure with selective in-loop filtering based on motion vector information is proposed. In the proposed scheme, the in-loop filter is applied only to the regions where there is motion. This is done so as not to affect the regions that are devoid of motion, since ghosting artifacts only occur in high-motion regions. It is shown that the proposed selective filtering method dramatically reduces ghosting artifacts in a wide variety of video sequences with pronounced frame-to-frame motion, without degrading the motionless regions.
Explosive molecular ionic crystals.

In ionic crystals of the form M+X-, certain covalently bonded anion groups X- are particularly associated with instability. The heavier metal cations M+ enhance this. Very sensitive explosives occur within the extended azide family, where X- = CNO-, N3-, NCO-, or NCS- (an isoelectronic set of unsaturated linear triatomic anions). Another such family are the globular oxyanions X- = ClO2-, ClO3-, ClO4-, NO3-, and MnO4-. Mishandling of NH4NO3 or NH4ClO4 has caused major disasters. An irreversible cyclic mechanism is proposed for such decomposition, involving mechanoelectronic band-gap excitation and coalescence of X with X-. From an intracrystalline ion-molecule collision complex, the singly charged dianion X2-, exothermic reactions proceed with high yield.
Theory of Exhaust-Plume/Boundary-Layer Interactions at Supersonic Speeds

At supersonic speeds, an under-expande d rocket exhaust jet produces a deflection of the external flow and generates a rise in pressure that communicates upstream through the surface boundary layer. For sufficiently large pressure ratios, the viscous layer separates some distance forward of the base and may seriously affect vehicle stability. The present investigation develops an integral method for predicting some of the main features of the nearfield interaction between the exhaust plume and the surface boundary layer. The analysis is not restricted to laminar flow and extends to turbulent interactions by utilizing a simplified eddy-diffusivity model. The method also applies to the interaction that occurs in the wake of inclined or asymmetric bodies, and results for the flow over a flat plate at angle of attack are given.
Richardson elements for classical Lie algebras

Parabolic subalgebras of semi-simple Lie algebras decompose as p = m circle plus n where m is a Levi factor and n the corresponding nilradical. By Richardson's theorem [R.W Richardson, Bull. London Math. Soc. 6 (1974) 21-24], there exists an open orbit under the action of the adjoint group P on the nilradical. The elements of this dense orbits are known as Richardson elements. In this paper we describe a normal form for Richardson elements in the classical case. This generalizes a construction for gl(N) of Briistle et al. [Algebr. Represent. Theory 2 (1999) 295-312] to the other classical Lie algebra and it extends the authors normal forms of Richardson elements for nice parabolic subalgebras of simple Lie algebras to arbitrary parabolic subalgebras of the classical Lie algebras [K. Baur, Represent. Theory 9 (2005) 30-45]. As applications we obtain a description of the support of Richardson elements and we recover the Bala-Carter label of the orbit of Richardson elements. (c) 2005 Elsevier Inc. All rights reserved.
Indexing U.S. government periodicals: Analysis and comments

Abstract The purpose of this article is to examine the indexing of U.S. government periodicals in terms of scope, specificity of indexing, organization, and currency. A number of general periodical indexes are analyzed by examination of Index to U.S. Government Periodicals , and American Statistics Index is emphasized. General conclusions are (1) coverage of government periodicals in traditional periodical indexes is inadequate, (2) adequate access to government periodicals is provided through IUSGP and ASI assuming that librarians and patrons are aware that they exist, and (3) IUSGP and ASI have relatively little duplication between them in terms of coverage and thus complement each other nicely. Specific recommendations for improvement of IUSGP, ASI , as well as improving bibliographic control of government periodicals in general, also are included.
Percutaneous method for multiple epicardial monophasic action potential recordings during magnetocardiographic mapping in intact rats

Abstract A surgical approach for subdiaphragmatic-programmed electrical stimulation (PES) in mice has been reported by Gutstein et al. [D.E. Gutstein, S.B. Danik, J.B. Sereysky, G.E. Morley, G.I. Fishman, Subdiaphragmatic murine electrophysiological studies: sequential determination of ventricular refractoriness and arrhythmia induction, Am J Physiol Heart Circ Physiol. 285 (3) (2003) H1091-96.]. We developed a percutaneous method to drive a patented magnetocardiography-compatible amagnetic catheter (AC), specifically designed for multiple monophasic action potentials (Multi-MAP) recording, at the epicardium of spontaneously breathing small animals. The aim of this study was to test the feasibility of simultaneous magnetocardiographic (MCG) estimate of ventricular repolarization (VR) and Multi-MAP recording in 5 rats. Under fluoroscopic control, the AC was introduced with a sub-xyphoid puncture, in all animals, and moved at several epicardial sites until 4 stable MAPs were recorded, with a fixed inter-electrode distance of 1 mm. An unshielded 36-channel DC-SQUID system (sensitivity 20 fT/Hz 1 / 2) was used to record the MCG. MAP signals, differentially amplified and filtered at DC-500 Hz, were digitized at 1 kHz. The same AC was used for programmed PES at pacing cycles between 200 and 250 ms. Ventricular effective refractory period (VERP) was evaluated with the accuracy of 2 ms. MAP duration (MAPd) was measured, at 90% levels of repolarization. Simultaneous MCG and MAP recordings were successful in all animals. One rat died for respiratory arrest. Four animals tolerated well the procedure and survived. In WRs, MAPd 90% and VERP were 67 ± 9.4 ms and 69.6 ± 5.6 ms, respectively. This minimally invasive method is well tolerated, avoids animal sacrifice, can be used to validate the accuracy of surface MCG estimate of dispersion of VR and for assessment of arrhythmogenic potential of new drugs.
1,3-Dipolar cycloaddition of alkynes to azides. Construction of operationally functional metal responsive fluorophores

The copper catalyzed 1,3-dipolar cycloaddition of 4-butoxyphenylazide with 2-, 3- or 4-ethynylpyridine furnishes 1,4-diaryltriazoles, which display turn-on fluorescence upon addition of metal cations.
Neutron scattering from transuranium materials

Abstract A number of neutron experiments on transuranium materials are reviewed. The purpose of these experiments, which range from studies of crystal-fields in the oxides to excitations in PuSb, is to increase our understanding of the 5f electron behaviour across the first half of the actinide series. Comparisons are made with the more familiar uranium analogues.
Structural complexity through multicomponent cycloaddition cascades enabled by dual-purpose, reactivity regenerating 1,2,3-triene equivalents

Multicomponent reactions allow for more bond-forming events per synthetic operation, enabling more step- and time-economical conversion of simple starting materials to complex and thus value-added targets. These processes invariably require that reactivity be relayed from intermediate to intermediate over several mechanistic steps until a termination event produces the final product. Here, we report a multicomponent process in which a novel 1,2,3-butatriene equivalent (TMSBO: TMSCH2C≡CCH2OH) engages chemospecifically as a two-carbon alkyne component in a metal-catalysed [5 + 2] cycloaddition with a vinylcyclopropane to produce an intermediate cycloadduct. Under the reaction conditions, this intermediate undergoes a remarkably rapid 1,4-Peterson elimination, producing a reactive four-carbon diene intermediate that is readily intercepted in either a metal-catalysed or thermal [4 + 2] cycloaddition. TMSBO thus serves as an yne-to-diene transmissive reagent coupling two powerful and convergent cycloadditions--the homologous Diels-Alder and Diels-Alder cycloadditions--through a vinylogous Peterson elimination, and enabling flexible access to diverse polycycles.
Optimal Fiscal Policy When Migration Is Feasible

This paper investigates how the feasibility of migration affects governments' optimal fiscal policies. We assume that households migrate toward economies where their welfare is higher, governments choose taxes and public expenditures to maximize a weighted sum of the households' welfare, welfare is increasing in public expenditures, and only distortionary labor income taxes are available. In isolated economies, the optimal fiscal policy implies that some households are net fiscal contributors, while other households are net fiscal beneficiaries. When households can migrate, however, governments compete for the households which are net fiscal contributors, and modify the fiscal policy in their favor, lowering their taxes and net fiscal contribution, and increasing their welfare. The magnitude of the effect increases with the sensitivity of migration to welfare. In the limiting case of free mobility, all households are zero net fiscal contributors. As to the patterns of migration, the model predicts that, with high migration costs, all households migrate toward the same high-productivity countries, which benefits low-productivity households, whereas with low migration costs, households with different productivities migrate toward different countries, which benefits high-productivity households.
Controlling quantum-dot light absorption and emission by a surface-plasmon field

The possibility for controlling both the probe-field optical gain and absorption, as well as photon conversion by a surface-plasmon-polariton near field is explored for a quantum dot located above a metal surface. In contrast to the linear response in the weak-coupling regime, the calculated spectra show an induced optical gain and a triply-split spontaneous emission peak resulting from the interference between the surface-plasmon field and the probe or self-emitted light field in such a strongly-coupled nonlinear system. Our result on the control of the mediated photon-photon interaction, very similar to the 'gate' control in an optical transistor, may be experimentally observable and applied to ultra-fast intrachip/interchip optical interconnects, improvement in the performance of fiber-optic communication networks, and developments of optical digital computers and quantum communications.
Observation and analysis of a slow termination process in the atom transfer radical polymerization of styrene

Abstract Under conditions in which the rate of polymerization is slow, we have observed the slow elimination of HBr from the polymer endgroups in the ATRP of styrene. Experimental evidence indicates that this process is likely due to the solvent effect on the stability of 1-PEBr at 110 °C. A second elimination reaction was observed in a hydrocarbon solvent. The major contribution to the second elimination process comes from the reaction of the Cu(II) species, formed after atom transfer, with the growing polymeric radical which presumably occurs via a one electron oxidation process. The bimolecular rate constant for the reaction of the growing polymeric radical with the Cu(II) species in an atom transfer process is approximately 10 3 to 10 4 times greater than for the same in a termination process. Thus, the chemoselectivity for atom transfer is very high, and the effect of this termination reaction is minimal under conditions in which the concentration of monomer is high and the concentration of Cu(II) species is at the minimum necessary to ensure good molecular weight control. These data also suggest that effect of this reaction is negligible for styrene polymerizations yielding low molecular weight polymer and that it should result in an upper molecular weight limit to styrene ATRP.