cssi/SciSciGPT-SciSciNet huggingface dataset:
First Constraints on Rings in the Pluto System

Simple theoretical calculations have suggested that small-body impacts onto Pluto's newly discovered small satellites, Nix and Hydra, are capable of generating time-variable rings or dust sheets in the Pluto system. Using Hubble Space Telescope ACS data obtained on 2006 February 15 and 2006 March 2, we find no observational evidence for such a ring system and present the first constraints on the present-day I/F and optical depth of a putative ring system, where I is the observed intensity and πF is the incident (solar) flux. At the 1500 km radial resolution of our search, we place a 3 σ upper limit on the azimuthally averaged normal I/F of ring particles of 5.1 × 10-7 at a distance of 42,000 km from the Pluto-Charon barycenter, the minimum distance for a dynamically stable ring (Stern et al. 1994; Nagy et al. 2006); 4.4 × 10-7 at the orbit of Nix; and 2.5 × 10-7 at the orbit of Hydra. For an assumed ring particle albedo of 0.04 (0.38), these I/F limits translate into 3 σ upper limits on the normal optical depth of macroscopic ring particles of 1.3 × 10-5 (1.4 × 10-6), 1.1 × 10-5 (1.2 × 10-6), and 6.4 × 10-6 (6.7 × 10-7), respectively. Were the New Horizons spacecraft to fly through a ring system with an optical depth of 1.3 × 10-5, it would collide with a significant number of potentially damaging ring particles. We therefore recommend that, unless tighter constraints can be obtained, New Horizons cross the putative ring plane within 42,000 km of the Pluto-Charon barycenter, where rings are dynamically unstable. We derive a crude estimate of the lifetime of putative ring particles of 900 yr.
Bond energy-bond order relations in transition-metal bonds: vanadium

Etude par spectroscopie de masse a faisceau d'ions des energies de liaison entre l'ion vanadium V + et l'hydrogene, l'oxygene et des coordinats carbones. Mise au point d'une correlation entre D o (V-A) et D o (H n C-A) (ou A:H, C, O, CH, C 2 H...)
Half-Heusler Semiconductors as Piezoelectrics

We use a first-principles rational-design approach to demonstrate the potential of semiconducting half-Heusler compounds as a previously unrecognized class of piezoelectric materials. We perform a high-throughput scan of a large number of compounds, testing for insulating character and calculating structural, dielectric, and piezoelectric properties. Our results provide guidance for the experimental realization and characterization of high-performance materials in this class that may be suitable for practical applications.
Multiple equilibria in a single‐column model of the tropical atmosphere

[1] A single-column model run under the weak temperature gradient approximation, a parameterization of large-scale dynamics appropriate for the tropical atmosphere, is shown to have multiple stable equilibria. Under conditions permitting persistent deep convection, the model has a statistically steady state in which such convection occurs, as well as an extremely dry state in which convection does not occur. Which state is reached depends on the initial moisture profile.
Acetylcholine receptor antibodies in patients with Graves' ophthalmopathy.

Objectives: To determine the frequency and clinical correlates of acetylcholine receptor (AChR) antibody seropositivity in patients with Graves' ophthalmopathy. Materials and Methods: Fifty consecutive new patients with Graves' ophthalmopathy diagnosed in an outpatient neuro-ophthalmology practice underwent determination of AChR-binding antibodies. Clinical and biochemical thyroid variables were compared between seropositive and seronegative patients. Clinical variables included age, sex, thyroid disorder, and duration and course of illness. Biochemical variables included thyroid hormone levels and thyroid antibodies. Seropositive patients were followed clinically to identify signs of myasthenia gravis. Results: Four of 50 (8%) patients had definitely elevated levels of AChR-binding antibodies. No obvious differences existed between the seropositive and seronegative groups in regards to age, sex, underlying thyroid disorder, biochemical thyroid state, presence of thyroid antibodies, or duration and course of their disease. None of the four seropositive patients developed signs of myasthenia gravis during the median follow-up period of 4.5 years. Conclusion: AChR-binding antibody seropositivity occurs in a small proportion of patients with Graves' ophthalmopathy but, by itself, does not necessarily identify an individual with concurrent myasthenia gravis or an individual at risk to develop myasthenia gravis.
Consideration of plant uncertainties in the optimum structural-control design

An integrated design approach for the optimum design of a controlled structure is presented. The control design method takes into consideration both structured and unstructured uncertainties by improving a bound on the H∞ norm of the closed-loop system and satisfying a constraint on the linear quadratic Gaussian performance index. The controller is designed by solving three Riccati equations. The weight of the structure is specified as an objective function with constraints on the structural frequencies, the closed-loop damping, and the performance index. The numerical results are presented for a three-dimensional truss structure to illustrate the application of the integrated approach
Circles minimize most knot energies

Abstract We define a new class of knot energies (known as renormalization energies ) and prove that a broad class of these energies are uniquely minimized by the round circle. Most of O'Hara's knot energies belong to this class. This proves two conjectures of O'Hara and of Freedman, He, and Wang. We also find energies not minimized by a round circle. The proof is based on a theorem of Lukő on average chord lengths of closed curves.
Comprehensive modeling of a liquid rocket combustion chamber

An analytical model for the simulation of detailed three-phase combustion flows inside a liquid rocket combustion chamber is presented. The three phases involved are: a multispecies gaseous phase, an incompressible liquid phase, and a particulate droplet phase. The gas and liquid phases are continuum described in an Eulerian fashion. A two-phase solution capability for these continuum media is obtained through a marriage of the Implicit Continuous Eulerian (ICE) technique and the fractional Volume of Fluid (VOF) free surface description method. On the other hand, the particulate phase is given a discrete treatment and described in a Lagrangian fashion. All three phases are hence treated rigorously. Semi-empirical physical models are used to describe all interphase coupling terms as well as the chemistry among gaseous components. Sample calculations using the model are given. The results show promising application to truly comprehensive modeling of complex liquid-fueled engine systems.
Closed quasi-Fuchsian surfaces in hyperbolic knot complements

said to be hyperbolic if it admits a complete hyperbolic metric of finite volume. By a surface we mean, in this paper, the complement of a finite (possibly empty) set of points in the interior of a compact, connected, orientable 2‐manifold. By a surface in a 3‐manifold M; we mean a continuous, proper map fW S! M from a surface S into M . A surface fW S! M in a 3‐manifold M is said to be incompressible if S is not a 2‐sphere and the induced homomorphism f W 1.S;s/! 1.M;f.s// is injective for one (and thus for any) choice of base point s in S . A surface fW S! M in a 3‐manifold M is said to be essential if it is incompressible and the map fW S! M cannot be homotoped into a boundary component or an end component of M . Essential surfaces in hyperbolic knot complements can be divided into three mutually exclusive geometric types: quasi-Fuchsian surfaces, geometrically infinite surfaces and essential surfaces with accidental parabolics. Now we recall the relevant terminology. Let H 3 denote the hyperbolic 3‐space (always in the upper half space model) and let S 2 1 D C[f1g denote the boundary at infinity, where C is the plane of complex numbers. Let H 3 D H 3 [S 2 1 be the compactification of H 3 ; which is topologically a compact 3‐ball. The action of every element of the orientation preserving isometry group Isom C .H 3 / extends to an action on H 3 . For a discrete subgroup A of
An Age Constraint for the Very Low Mass Stellar/Brown Dwarf Binary 2MASS J03202839?0446358AB

2MASS J03202839-0446358AB is a recently identified, late-type M dwarf/T dwarf spectroscopic binary system for which both the radial velocity orbit for the primary and spectral types for both components have been determined. By combining these measurements with predictions from four different sets of evolutionary models, we determine a minimum age of 2.0 {+-} 0.3 Gyr for this system, corresponding to minimum primary and secondary masses of 0.080 M {sub sun} and 0.053 M {sub sun}, respectively. We find broad agreement in the inferred age and mass constraints between the evolutionary models, including those that incorporate atmospheric condensate grain opacity; however, we are not able to independently assess their accuracy. The inferred minimum age agrees with the kinematics and absence of magnetic activity in this system, but not the rapid rotation of its primary, further evidence of a breakdown in angular momentum evolution trends amongst the lowest luminosity stars. Assuming a maximum age of 10 Gyr, we constrain the orbital inclination of this system to i {approx}> 53{sup 0}. More precise constraints on the orbital inclination and/or component masses of 2MASS 0320-0446AB, through either measurement of the secondary radial velocity orbit (optimally in the 1.2-1.3 {mu}m band) or detection of anmore » eclipse (only 0.3% probability based on geometric constraints), would yield a bounded age estimate for this system, and the opportunity to use it as an empirical test for brown dwarf evolutionary models at late ages.« less
A Deodhar-type stratification on the double flag variety

We describe a partition of the double flag variety G/B+ × G/B- of a complex semisimple algebraic group G analogous to the Deodhar partition on the flag variety G/B+. This partition is a refinement of the stratification into orbits both for B+ × B- and for the diagonal action of G, just as Deodhar's partition refines the orbits of B+ and B-. We give a coordinate system on each stratum, and show that all strata are coisotropic subvarieties. Also, we discuss possible connections to the positive and cluster geometry of G/B+ × G/B-, which would generalize results of Fomin and Zelevinsky on double Bruhat cells and Marsh and Rietsch on double Schubert cells.
A study of conjugate addition to a γ,δ-dioxolanyl-α,β-unsaturated ester

Abstract Diastereoselective phenylcuprate addition to (S)-3-(2,2-dimethyl-1,3-dioxolan-4-yl)-trans-2-propenoate has been achieved in the presence of lithium bromide, copper(I) cyanide, trimethylsilyl chloride and dimethylsulfide cocatalysts.
The Use of tert-Butyl Vinyl Ether in Stepwise Electrophilic Addition Reactions.

Abstract tert-Butyl vinyl ether (1) reacts with p-TolSCl to give 2-tert-butoxy-2-chloroethyl p-tolyl sulfide (2). In the presence of SnCl4, 2 reacts with silyl enol ethers, allyltrimethylsilane, and vinyl ethers to form a C-C bond. In the case of vinyl ethers, the reaction proceeds through the formation of the 5-membered sulfonium salt intermediate which in turn can react with H2O, TMSCN, allyltrimethylsilane, and Grignard reagents.
Triarylamine-enchained semifluorinated perfluorocycloalkenyl (PFCA) aryl ether polymers

A variety of perfluorocycloalkenyl (PFCA) aryl ether monomers and polymers with enchained triarylamine units were successfully synthesized, characterized and reported here. These polymers are highly thermally stable and show variable thermal properties. Successful conversion of the newly synthesized TAA enchained perfluorocyclopentenyl (PFCP) aryl ether polymers via formylation and EAS demonstrates the synthetic versatility of TAA moiety and provides an excellent option for application specific post polymerization reactions. The cross-linking behavior of PFCP aryl ether polymers was studied under different reaction conditions. The combination of processability, thermal stabilities, and tailorability makes these polymers suitable for a wide variety of applications including electro-optics, proton exchange membranes and super-hydrophobic applications.
Detection of X-Ray-emitting Hypernova Remnants in M101

Based on an ultradeep (230 ks) ROSAT HRI imaging of M101, we have detected five X-ray sources that coincide spatially with optical emission line features previously classified as supernova remnants (SNRs) in this nearby galaxy. Two of these coincidences (SNR MF 83 and NGC 5471B) most likely represent the true physical association of X-ray emission with shock-heated interstellar gas. MF 83, with a radius of ~134 pc, is one of the largest remnants known. NGC 5471B, with a radius of 30 pc and a velocity of at least 350 km s-1 (FWZI), is extremely bright in both radio and optical. The X-ray luminosities of these two shell-like remnants are ~1 and 3×1038 ergs s-1 (0.5-2 keV), about an order of magnitude brighter than the brightest supernova remnants known in our Galaxy and in the Magellanic Clouds. The inferred blast-wave energy is ~3×1052 ergs for NGC 5471B and ~3×1053 ergs for MF 83. Therefore, the remnants likely originate in hypernovae, which are a factor of 10 more energetic than canonical supernovae and are postulated as being responsible for gamma-ray bursts observed at cosmological distances. The study of such hypernova remnants in nearby galaxies has the potential to provide important constraints on the progenitor type, rate, energetics, and beaming effect of gamma-ray bursts.
Thio FCMA Intermediates as Strong Acyl Donors: A General Solution to the Formation of Complex Amide Bonds

Novel methodology for the formation of amide bonds under neutral conditions is described. Evidence is presented that the active acyl donors are thio FCMA intermediates, generated from the reactions of thioacids with isonitriles.
Twining genera of (0,4) supersymmetric sigma models on K3

Conformal field theories with (0,4) worldsheet supersymmetry and K3 target can be used to compactify the E 8 × E 8 heterotic string to six dimensions in a supersymmetric manner. The data specifying such a model includes an appropriate configuration of 24 gauge instantons in the E 8 × E 8 gauge group to satisfy the constraints of anomaly cancellation. In this note, we compute twining genera — elliptic genera with appropriate insertions of discrete symmetry generators in the trace — for (0,4) theories with various instanton embeddings. We do this by constructing linear sigma models which flow to the desired conformal field theories, and using the techniques of localization. We present several examples of such twining genera which are consistent with a moonshine relating these (0,4) models to the finite simple sporadic group M 24.
On the matter of the Dijkgraaf-Vafa conjecture

With the aim of extending the gauge theory-matrix model connection to more general matter representations, we prove that for various two-index tensors of the classical gauge groups, the perturbative contributions to the glueball superpotential reduce to matrix integrals. Contributing diagrams consist of certain combinations of spheres, disks, and projective planes, which we evaluate to four and five loop order. In the case of Sp(N) with antisymmetric matter, independent results are obtained by computing the nonperturbative superpotential for N = 4,6 and 8. Comparison with the Dijkgraaf-Vafa approach reveals agreement up to N/2 loops in matrix model perturbation theory, with disagreement setting in at h = N/2 + 1 loops, h being the dual Coxeter number. At this order, the glueball superfield S begins to obey nontrivial relations due to its underlying structure as a product of fermionic superfields. We therefore find a relatively simple example of an = 1 gauge theory admitting a large-N expansion, whose dynamically generated superpotential differs from the one obtained in the matrix model approach.
A Recalibration of IUE NEWSIPS Low-Dispersion Data

While the low-dispersion IUE New Spectroscopic Image Processing System (NEWSIPS) data products represent a significant improvement over original IUE Spectroscopic Image Processing System (SIPS) data, they still contain serious systematic effects which compromise their utility for certain applications. We show that NEWSIPS low-resolution data are internally consistent to only 10%-15% at best, with the majority of the problem due to time-dependent systematic effects. In addition, the NEWSIPS flux calibration is shown to be inconsistent by nearly 10%. We examine the origin of these problems and proceed to formulate and apply algorithms to correct them to the ~3% level—a factor of 5 improvement in accuracy. Because of the temporal systematics, transforming the corrected data to the IUE flux calibration becomes ambiguous. Therefore, we elect to transform the corrected data onto the Hubble Space Telescope Faint Object Spectrograph system. This system is far more self-consistent, and transforming the IUE data to it places data from both telescopes on a single system. Finally, we perform a detailed error analysis of the corrected NEWSIPS data. We demonstrate that much of the remaining 3% systematic effects in the corrected data is traceable to problems with the NEWSIPS intensity transformation function (ITF). The accuracy could probably be doubled by rederiving the ITF.
Safety-belt effectiveness: The influence of crash severity and selective recruitment

While theoretical considerations show that the effectiveness of occupant protection devices declines from 100% at very low crash severity to 0% at high severity, empirical details have been lacking. When overall in-use effectiveness is estimated by applying traditional methods to data sets that lack a measure of severity, large biases are introduced because non-wearing drivers are riskier drivers, an effect that has been called selective recruitment. These effects are investigated empirically using National Accident Sampling System (NASS) data in which crash severity is measured by delta-v, the estimated change in the speed of the car as a result of the crash. Supplemental results are obtained using published police-reported data containing a more easily obtained but less objective severity measure. Both data sets provide information on driver fatalities and injuries, thus allowing four comparisons of effectiveness estimates based only on total casualties with ones taking into account the different severities of crashes by belted and unbelted drivers. The data show consistently that the probability that a driver is belted declines as crash severity increases. Belt effectiveness estimates ignoring this effect are biased upwards by large amounts (for example, 60% compared to 40% for injuries using NASS data). Belts appear more effective at preventing fatalities than at preventing injuries. The results are consistent with a prior estimate, derived using a method unaffected by the biases discussed here, which found that, averaged over all crashes, safety belts reduce driver fatality risk by (42 +/- 4).
The Format Model: A Theory of database Organization

A mathematical theory for the study of data representation in databases is introduced and developed. The theory focuses on three data constructs (collection, composition and classification). "Formats" with semantically rich yet tractable structure are built recursively using these constructs. Using formats, we obtain several nontrivial results concerning notions of relative information capacity and restructuring of data sets. As such, the format model provides a new approach for the formal study of the construction of "user views" and other data manipulations in databases.
EVOLUTION OF CHEMISTRY AND MOLECULAR LINE PROFILES DURING PROTOSTELLAR COLLAPSE

Understanding the chemical evolution in star-forming cores is a necessary precondition to correctly assessing physical conditions when using molecular emission. We follow the evolution of chemistry and molecular line profiles through the entire star formation process, including a self-consistent treatment of dynamics, dust continuum radiative transfer, gas energetics, chemistry, molecular excitation, and line radiative transfer. In particular, the chemical code follows a gas parcel as it falls toward the center, passing through regimes of density, dust temperature, and gas temperature that are changing because of both the motion of the parcel and the evolving luminosity of the central source. We combine a sequence of Bonnor-Ebert spheres and the inside-out collapse model to describe dynamics from the pre-protostellar stage to later stages. The overall structures of abundance profiles show complex behavior that can be understood as interactions between freezeout and evaporation of molecules. We find that the presence or absence of gas-phase CO has a tremendous effect on the less abundant species. In addition, the ambient radiation field and the grain properties have important effects on the chemical evolution, and the variations in abundance have strong effects on the predicted emission-line profiles. Multitransition and multiposition observations are necessary to constrain the parameters and interpret observations correctly in terms of physical conditions. Good spatial and spectral resolution is also important in distinguishing evolutionary stages.
Palladium-Catalyzed One-Step Synthesis of Isoindole-1,3-diones by Carbonylative Cyclization of o-Halobenzoates and Primary Amines

The palladium-catalyzed aminocarbonylation of o-halobenzoates produces 2-substituted isoindole-1,3-diones in good yields. This methodology provides a good one-step approach to this important class of heterocycles and tolerates a variety of functional groups, including methoxy, alcohol, ketone, and nitro groups.
The Sampling Relationship Between Sharpe's Performance Measure and its Risk Proxy: Sample Size, Investment Horizon and Market Conditions

Sharpe's, Treynor's and Jensen's measures have been extensively used for the performance evaluation of mutual funds or portfolios. These three widely used performance measures have been found to be highly correlated with their corresponding risk measures by a number of empirical studies. This paper focuses the investigation on the possible sources of the bias associated with the empirical relationship between the estimated Sharpe's measure and its estimated risk measure. In general, the sample size, the investment horizon and the market conditions are three important factors in determining the strong relationship between the ex-post Sharpe's measure and its estimated risk surrogate. The interesting findings of this study are as follows: 1 the estimated Sharpe's measure is uncorrelated with the estimated risk measure either when the risk free rate of interest equals the expected return on the market portfolio over the sample period or when the sample size is infinite, 2 the estimated Sharpe's measure is positively or negatively correlated with the estimated risk measure if the risk-free rate of interest is greater than or less than the expected return on the market portfolio, 3 an observation horizon shorter than the true investment horizon can reduce the dependence of the estimated Sharpe's measure on its estimated risk measure, and 4 an observation horizon longer than the true investment horizon will magnify the dependence. The results have indicated that, in conducting empirical research, a shorter observation horizon and a large sample size should be used to reduce the bias associated with the estimated Sharpe's measure.
GUT AND SUSY BREAKING BY THE SAME FIELD

Abstract We present a model in which the same modulus field breaks both SUSY and a simple GUT gauge group down to the SM gauge group. The modulus is stabilized by the inverted hierarchy mechanism in a perturbative region so that the model is calculable. This is the first example of this kind in the literature. All mass scales (other than the Planck scale) are generated dynamically. In one of the models doublet-triplet splitting is achieved naturally by the sliding singlet mechanism while another model requires fine tuning. The gauge mediation contribution to the right handed slepton (mass)2 is negative. But, for the modulus vacuum expectation value close to the GUT scale, the supergravity contribution to the slepton (mass)2 is comparable to the gauge mediation contribution and thus a realistic spectrum can be attained.
Grammatical Models of Organizational Processes

Grammar has been used metaphorically to describe organizational processes, but the metaphor has never been systematically developed so that it can be applied in empirical research. This paper develops the grammatical metaphor into a rigorous model for describing and theorizing about organizational work processes, defined here as sequences of actions that occur in the context of enabling and constraining structures. A grammatical model starts with a lexicon of elementary actions called moves and specifies the ways in which they can be combined to create a process. Unlike other sequential data analysis techniques, grammatical models provide a natural way of describing the layering and nesting of actions that typifies organizational processes. The example of a simple retail sales transaction is used to illustrate the underlying concepts. The paper also examines some methodological considerations involved in using process grammars and proposes an agenda for research, including: 1 creating descriptive taxonomies of organizational processes; 2 creating disconfirmable theories about the relationship between processes and the structures that enable and constrain them; 3 explaining the distribution of observed processes and predicting new processes that have not yet been observed; and 4 designing new organizational processes.
Chemoenzymatic synthesis of 1,3-dideoxynojirimycin

Abstract Enone 3 , readily available from cyclopentadiene, was transformed via Pd(0)-mediated carbon monoxide coupling, ozonolysis and reductive amination to enantiopure 1,3-dideoxynojirimycin ( 7 ) in high diastereoselectivity.
Terrace width variations in complex lunar craters

The widths of terrace structures in complex craters on the moon are compared to existing theoretical models of their origin. Terrace widths in an individual crater increase monotonically outward toward the crater rim. Similarly, the width W of the terraces lying closest to the rim of a crater of diameter D increases monotonically, obeying a least-squares power-law relation WS (km) = 0.09D exp 0.87 km). A simple model of slumping that ignores inertial forces and assumes a constant bedrock yield strength is in good agreement with the observations.
Compressive wavefront sensing with weak values

We demonstrate a wavefront sensor that unites weak measurement and the compressive-sensing, single-pixel camera. Using a high-resolution spatial light modulator (SLM) as a variable waveplate, we weakly couple an optical field's transverse-position and polarization degrees of freedom. By placing random, binary patterns on the SLM, polarization serves as a meter for directly measuring random projections of the wavefront's real and imaginary components. Compressive-sensing optimization techniques can then recover the wavefront. We acquire high quality, 256 × 256 pixel images of the wavefront from only 10,000 projections. Photon-counting detectors give sub-picowatt sensitivity.
Asymptotic properties of model selection procedures in linear regression

In the regression analysis, there is typically a large collection of competing models available from which we want to select an appropriate one. This article is concerned with asymptotic properties of procedures for selecting linear models, which are based on certain data-dependent criteria such as Mallows’ C p , cross-validation and the generalized information criterion. We avoid the assumption of an adequate (‘correct’) model and allow the maximal model dimension to increase with the sample size. General asymptotic concepts are introduced, covering the usual ones of consistency and asymptotic optimality. The focus is on conditions for penalizing the model complexity, which are necessary to obtain the different optimality properties. For example, the consistency of a procedure is decided by the interplay between these penalties, the complexity of the class of model candidates, and some quantity describing the ability to identify ‘wrong’ (pseudo-inadequate) models. Many results known from the literature a...
Kolmogorov Similarity Hypotheses for Scalar Fields: Sampling Intermittent Turbulent Mixing in the Ocean and Galaxy

Kolmogorov's three universal similarity hypotheses are extrapolated to describe scalar fields like temperature mixed by turbulence. The analogous first and second hypotheses for scalars include the effects of Prandtl number and rate-of-strain mixing. Application of velocity and scalar similarity hypotheses to the ocean must take into account the damping of active turbulence by density stratification and the Earth's rotation to form fossil turbulence. By the analogous Kolmogorov third hypothesis for scalars, temperature dissipation rates $\chi $ averaged over lengths r > L$\_{\text{K}}$ should be lognormally distributed with intermittency factors $\sigma ^{2}$ that increase with increasing turbulence energy length scales L$\_{\text{O}}$ as $\sigma \_{\ln \langle \chi \rangle \_{r}}^{2}\approx \mu \_{\theta}$ ln (L$\_{\text{O}}$/r). Tests of kolmogorovian velocity and scalar universal similarity hypotheses for very large ranges of turbulence length and timescales are provided by data from the ocean and the galactic interstellar medium. These ranges are from 1 to 9 decades in the ocean, and over 12 decades in the interstellar medium. The universal constant for turbulent mixing intermittency $\mu _{\theta}$ is estimated from oceanic data to be 0.44 $\pm $ 0.01, which is remarkably close to estimates for Kolmogorov's turbulence intermittency constant $\mu $ of 0.45 $\pm $ 0.05 from galactic as well as atmospheric data. Extreme intermittency complicates the oceanic sampling problem, and may lead to quantitative and qualitative undersampling errors in estimates of mean oceanic dissipation rates and fluxes. Intermittency of turbulence and mixing in the interstellar medium may be a factor in the formation of stars.
Air mass classification in coastal New England and its relationship to meteorological conditions

[1] The dominant air mass types along coastal New England during summer 2004 were classified and their relationship to synoptic meteorological conditions investigated as a component of the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign. Representative air mass types were defined on the basis of variability in the occurrence of volatile organic compounds (VOCs), and they were further grouped into distinct source-related categories. Emissions from nearby anthropogenic sources were found to govern the total variance of the data set (58% at Appledore Island (AI) and 56% at Thompson Farm (TF)), whereas long-distance transport was much less dominant (15% on AI and 17% at TF). This result indicates frequent influence from recent anthropogenic emissions at TF and AI, with periodic inputs of aged/processed pollutants. The fractional time periods dominated by anthropogenic (recent and aged/processed) and marine biogenic air masses were almost the same at TF and AI (36% versus 30% and 14% versus 16% respectively), clearly showing the strong impact of continental outflow on the nearshore marine atmosphere and a surprising persistent influence of marine biogenic emissions at an inland site. Empirical orthogonal function (EOF) analysis suggested that the most important circulation pattern during summer 2004 was characterized by a low trough positioned along coastal New England, leaving this region under the control of northwesterly flow from central Canada. This result helps explain why New England in summer 2004 was less polluted compared to previous years.
Distance estimation and object location via rings of neighbors

We consider four problems on distance estimation and object location which share the common flavor of capturing global information via informative node labels: low-stretch routing schemes [48], distance labeling [25], searchable small worlds [31], and triangulation-based distance estimation [34]. Focusing on metrics of low doubling dimension, we approach these problems with a common technique called rings of neighbors, which refers to a sparse distributed data structure that underlies all our constructions. Apart from improving the previously known bounds for these problems, our contributions include extending Kleinberg’s small world model to doubling metrics, and a short proof of the main result in Chan et al. [15]. Doubling dimension is a notion of dimensionality for general metrics that has recently become a useful algorithmic concept in the theoretical computer science literature.
Self-consistent calculation for valence subband structure and hole mobility in p-channel inversion layers

Using six- and eight-band k⋅p models—with parameters calibrated against the bulk band structure obtained using non-local empirical pseudopotentials—we have employed a new hybrid self-consistent method to calculate the valence subband structure in p-channel inversion layers of InAs, InSb, GaAs, In0.53Ga0.47As, and GaSb. This method involves two separate stages: first, density-of-states (DOS) of the three lowest-energy subbands (heavy, light, and split-off holes) is calculated using the triangular-well approximation. Then, the self-consistent calculation is performed using the DOS previously obtained, but shifting each subband by the amount obtained from the self-consistent eigenvalues obtained during the self-consistent iteration. Finally, we present results regarding the hole mobility in Ge p-channel inversion layers. The results are compared to those obtained employing the subband structure computed with the triangular-well approximation and also with experimental data.
Time optimal trajectories for mobile robots with two independently driven wheels

This paper addresses the problem of time-optional motions for a mobile platform in a planar environment. The platform has two non-steerable independently driven wheels. The overall mission of the robot is expressed in terms of a sequence of via points at which the platform must be at rest in a given configuration (position and orientation). The objective is to plan time-optimal trajectories between these configurations assuming an unobstructed environment. Using Pontryagin`s maximum principle (PMP), we formally demonstrate that all time optimal motions of the platform for this problem occur for bang-bang controls on the wheels (at each instant, the acceleration on each wheel is either at its upper or lower limit). The PMP, however, only provides necessary conditions for time optimality. To find the time optimal robot trajectories, we first parameterize the bang-bang trajectories using the switch times on the wheels (the times at which the wheel accelerations change sign). With this parameterization, we can fully search the robot trajectory space and find the switch times that will produce particular paths to a desired final configuration of the platform. We show numerically that robot trajectories with three switch times (two on one wheel, one on the other) can reach anymore » position, while trajectories with four switch times can reach any configuration. By numerical comparison with other trajectories involving similar or greater numbers of switch times, we then identify the sets of time-optimal trajectories. These are uniquely defined using ranges of the parameters, and consist of subsets of trajectories with three switch times for the problem when the final orientation of the robot is not specified, and four switch times when a full final configuration is specified. We conclude with a description of the use of the method for trajectory planning for one of our robots.« less
Case study of a functional genomics application for an FPGA-based coprocessor

Abstract Although microarrays are already having a tremendous impact on biomedical science, they still present great computational challenges. We examine a particular problem involving the computation of linear regressions on a large number of vector combinations in a high-dimensional parameter space, a problem that was found to be virtually intractable on a PC cluster. We observe that characteristics of this problem map particularly well to FPGAs and confirm this with an implementation that results in a 1600-fold speed-up over an optimized serial implementation. Some of the other contributions involve the data routing structure, the analysis of bit-width allocation, and the handling of missing data. Since this problem is representative of many in functional genomics, part of the overall significance of this work is that it points to a new area of applicability for FPGA coprocessors.
In Utero Progression of Isolated Renal Pelvis Dilation

The objective of this study to determine the risk of in uteroprogression of renal pelvis dilation when detected on antenatal ultrasound examination. We reviewed 230 fetuses with evidence of renal pelvis dilation. At least one exam was subsequently performed prior to delivery in all cases. Renal pelvis dilation was defined as an anterior-posterior renal pelvis measurement > 4 mm at 7 mm at > or = 32 weeks' gestation. Hydronephrosis was considered to be present when the renal pelvis measured +10 mm independent of gestational age. Multiple gestations and fetuses with additional congenital anomalies were excluded. The mean gestational age at diagnosis was 24 weeks. Renal pelvis dilation progressed to hydronephrosis in a total of 10.9% (25 of 230) of fetuses. There was a 3.3% chance of unilateral renal pelvis dilation progressing to hydronephrosis versus 26.0% in bilateral dilation (OR 10.4 [95% Cl 3.5-33.3]). Of those fetuses with progression, 80% had bilateral dilation (p < 0.0001). There was no difference in progression between right and left kidneys. Additionally, gender, gestational age at diagnosis and delivery, and birth weight did not differ between those fetuses with and without progression. The hydronephrosis in 7 of 25 (28%) regressed to pyelectasis on a subsequent ultrasound exam. Thus, the overall rate of progression of renal pelvis dilation to persistent hydronephrosis was 7.8% (18 of 230). In conclusion, the risk of isolated renal pelvis dilation progressing to hydronephrosis is low. Although bilateral pelvis dilation carries a higher risk for progression, no fetus in our study required in utero intervention. A follow up scan prior to delivery may be considered to identify those fetuses who will require postpartum intervention.
Materials for small radius leading edges for hypersonic vehicles.

Symmetrical wedge models of sharp leading edges were fabricated from candidate refractory materials and tested in a 10-Mw-arc-heated, freejet facility producing nominal plenum conditions of 380 psia and 5500 °F. Experiments were first conducted with specially developed temperature probes to determine heat-transfer coefficients and recovery temperature at various stations in the freejet. Tests of the models were then carried out at appropriate stations in the freejet to produce tip temperatures in the range 3200-3900°F to simulate temperatures such as would be encountered in flight at velocities up to 7800 fps at altitudes near 70,000 ft. Successful performance was obtained with several models having 0.03-in. or smaller radii with little or no erosion occurring during runs of 13 sec duration. The best results were obtained with solid models of a ductile metallic alloy of hafnium-20% tantalum and with coatings of this alloy on a graphite or tantalum-10% tungsten alloy substrate. Several brittle materials, such as metallic carbides and boron nitride, showed good erosion resistance, but fracture was frequently encountered due to the unusually severe thermal shock associated with the test. The results indicate that the materials may be serviceable at similar velocities and altitudes near sea level.
The double ramification cycle and the theta divisor

We compute the classes of universal theta divisors of degrees zero and g-1 over the Deligne-Mumford compactification of the moduli space of curves, with various integer weights on the points, in particular reproving a recent result of M\"uller. We also obtain a formula for the class in the Chow ring of the moduli space of curves of compact type of the double ramification locus, given by the condition that a fixed linear combination of the marked points is a principal divisor, reproving a recent result of Hain. Our approach for computing the theta divisor is more direct, via test curves and the geometry of the theta divisor, and works easily over the entire Deligne-Mumford compactification. We use our extended result in another paper to study the partial compactification of the double ramification cycle.
Aesthetic Experience: From Analysis to Eros

Despite its technical and relatively modern coinage by a rationalist philosopher in the mideighteenth century, the concept of the aesthetic has proven so very vague, variable, and contested that theorists working in the field it supposedly defines have often expressed distinct frustration and sometimes even skepticism concerning this concept and its cognates (such as aesthetic attitude, aesthetic judgment). One source of the concept's blurredness is that the aesthetic ambiguously refers not only to distinctive but also diverse objects of perception (whether these be artworks, other artifacts, natural things, or even simply distinctive qualities, such as beauty, grace, and so forth, that can be found in these objects). It also refers to a distinctive mode of consciousness that grasps such objects-the very term 'aesthetic' being derived from the Greek word for sensory perception and used by Alexander Baumgarten, its inventor, to characterize what he regarded as our lower or more sensory faculties of cognition. To complicate things further, 'aesthetic' also applies to the distinctive discourse used to discuss those objects and modes of perception. Even more elusively vague, problematically polysemic, and confusingly controversial than the aesthetic, while also older, more central, and more influential in philosophical inquiry, is the concept of experience. Already a contested notion in ancient Greece where it was often
Existence of self-financing and Pareto-improving congestion pricing: Impact of value of time distribution

This paper considers a static congestion pricing model in which travelers select a mode from either, driving on highway or taking public transit, to minimize a combination of travel time, operating cost and toll. The focus is to examine how travelers' value of time (VOT), which is continuously distributed in a population, affects the existence of a pricing-refunding scheme that is both self-financing (i.e. requiring no external subsidy) and Pareto-improving (i.e. reducing system travel time while making nobody worse off). A condition that insures the existence of a self-financing and Pareto-improving (SFPI) toll scheme is derived. The authors' derivation reveals that the toll authority can select a proper SFPI scheme to distribute the benefits from congestion pricing through a credit-based pricing scheme. Under mild assumptions, the authors prove that an SFPI toll always exists for concave VOT functions, of which the linear function corresponding to the uniform distribution is a special case. Existence conditions are also established for a class of rational functions. These results can be used to analyze more realistic VOT distributions such as log-normal distribution. A useful implication of study analysis is that the existence of an SFPI scheme is not guaranteed for general functional forms. Thus, external subsidies may be required to ensure Pareto-improving, even if policy-makers are willing to return all toll revenues to road users.
Electrographic Instrumentation For Ultraviolet Imaging And Spectrography

The latest results in the Naval Research Laboratory program of far-ultraviolet electrographic camera development, and application of these cameras to astrophysical and upper-atmospheric investigations, are presented. A new large electrographic Schmidt camera, of 15 cm aperture and f/2 focal ratio, has been successfully used in two sounding rocket flights, one for direct imagery in the 1230-2000 A wavelength range and the second for objective spectrography in the 950-2000 A range, of stars and nebulae in the Cygnus region of the sky. The camera has an 11° field of view and better than 30 arc sec resolution (2 A spectral resolution with 600 line/mm objective grating). A nebular spectrograph, based on a microchannel-intensified electrographic Schmidt camera, was then payload of a June 1979 rocket flight. It covers the 1050-2000 A range, and can reach emission line features as faint as 10 Rayleighs in 60 second ex-posures with 5 A spectral resolution. Electrographic cameras with mesh-based semitransparent photocathodes, capable of observations in the extreme ultraviolet below 1050 A, are being developed for a number of space science applications. A camera with microchannel intensification is the detector in an XUV airglow/auroral spectrograph used in a February 1978 rocket flight, and cameras without microchannel intensification are proposed for various solar XUV spectrographic and spectroheliographic applications.
General neutralino NLSPs at the early LHC

Gauge mediated supersymmetry breaking (GMSB) is a theoretically well-motivated framework with rich and varied collider phenomenology. In this paper, we study the Tevatron limits and LHC discovery potential for a wide class of GMSB scenarios in which the next-to-lightest superpartner (NLSP) is a promptly-decaying neutralino. These scenarios give rise to signatures involving hard photons, W ’s, Z’s, jets and/or higgses, plus missing energy. In order to characterize these signatures, we define a small number of minimal spectra, in the context of General Gauge Mediation, which are parameterized by the mass of the NLSP and the gluino. Using these minimal spectra, we determine the most promising discovery channels for general neutralino NLSPs. We find that the 2010 dataset can already cover new ground with strong production for all NLSP types. With the upcoming 2011-2012 dataset, we find that the LHC will also have sensitivity to direct electroweak production of neutralino NLSPs.
Modeling and analysis of bias-ply motorcycle tires

Abstract Physical properties of motorcycle tire structure are considered to help select a good and true-to-life mechanistic model suitable for finite element analysis of tires. Rubber and bias-ply layered-cord together make the inflated unhomogeneous tire structure anisotropic and geometrically highly nonlinear. A mathematical model made of 3-D solid and truss elements is discussed, and presented as realistic and adequate to accommodate the anisotropy and nonlinearity inherent in the tire problem. Various loading cases, including a cambered tire with inflation pressure and vertical load on contact patch, are studied and evaluated for force and moment acting on the tire. The results are very encouraging and satisfactory.
Intermolecular ene reactions utilizing oxazolones and enol ethers.

We report herein an intermolecular ene reaction using oxazolones with enol ethers which results in the formation of novel quaternary amino esters in near quantitative yields. The overall reaction transformation closely resembles an intermolecular version of the Conia-ene reaction. The reactions are uncatalyzed and occur under very mild conditions.