cssi/SciSciGPT-SciSciNet huggingface dataset:
Characterizing 1-dof Henneberg-I graphs with efficient configuration spaces

We define and study exact, efficient representations of realization spaces of a natural class of underconstrained 2D Euclidean Distance constraint systems (Linkages or Frameworks) based on 1-dof Henneberg-I graphs. Each representation corresponds to a choice of parameters and yields a different parametrized configuration space. Our notion of efficiency is based on the algebraic complexities of sampling the configuration space and of obtaining a realization from the sample (parametrized) configuration. Significantly, we give purely combinatorial characterizations that capture (i) the class of graphs that have efficient configuration spaces and (ii) the possible choices of representation parameters that yield efficient configuration spaces for a given graph. Our results automatically yield an efficient algorithm for sampling realizations, without missing extreme or boundary realizations. In addition, our results formally show that our definition of efficient configuration space is robust and that our characterizations are tight. We choose the class of 1-dof Henneberg-I graphs in order to take the next step in a systematic and graded program of combinatorial characterizations of efficient configuration spaces. In particular, the results presented here are the first characterizations that go beyond graphs that have connected and convex configuration spaces.
Relaxation of nonlinear oscillations in BCS superconductivity

The diagonal case of the sl(2) Richardson–Gaudin quantum pairing model is known to be solvable as an Abel–Jacobi inversion problem. The effect of random time-dependent perturbations of the single-particle spectrum on the exact solution is an open question of considerable physical relevance. Weak perturbations introduce a new, slow time scale, while preserving the nonlinear character of the dynamics. In this paper, such perturbations are considered. It is shown that the long-time asymptotics can be obtained by a deformation of the original integrable system, equivalent to phase averaging over the fast time scale.
Bases for chain-complete posets

Various authors (especially Scott, Egli, and Constable) have introduced concepts of "basis" for various classes of partially ordered sets (posets). This paper studies a basis concept directly analogous to the concept of a basis for a vector space. The new basis concept includes that of Egli and Constable as a special case, and one of their theorems is a corollary of our results. This paper also summarizes some previously reported but little known results of wide utility. For example, if every linearly ordered subset (chain) in a poset has a least upper bound (supremum), so does every directed subset. Given posets P and Q, it is often useful to construct maps g: P → Q that are Chain-continuous: supremums of nonempty chains are preserved. Chain-continuity is analogous to topological continuity and is generally much more difficult to verify than isofonicity: the preservation of the order relation. This paper introduces the concept of an extension basis: a subset B of P such that any isotone f: B → Q has a unique chain-continuous extension g: P → Q. Two characterizations of the chain-complete posets that have extension bases are obtained. These results are then applied to the problem of constructing an extension basis for the poset [P → Q] of chain-continuous maps from P to Q, given extension bases for P and Q. This is not always possible, but it becomes possible when a mild (and independently motivated) restriction is imposed on either P or Q. A lattice structure is not needed.
Disclination loop behavior near the nematic-isotropic transition

We investigate the behavior of disclination loops in the vicinity of the first-order nematic-isotropic transition in the Lebwohl-Lasher and related models. We find that two independent measures of the transition temperature, the free energy, and the distribution of disclination line segments, give essentially identical values. We also calculate the distribution function D(p) of disclination loops of perimeter p and fit it to a quasiexponential form. Below the transition, D(p) falls off exponentially, while in the neighborhood of the transition, it decays with a power-law exponent approximately equal to 2.5, consistent with a "blowout" of loops at the transition. In a modified Lebwohl-Lasher model with a strongly first-order transition we are able to measure a jump in the disclination line tension at the transition, which is too small to be measured in the Lebwohl-Lasher model. We also measure the monopole charge of the disclination loops and find that in both the original and modified Lebwohl-Lasher models, there are large loops that carry monopole charge, while smaller isolated loops do not. Overall, the nature of the topological defects in both models is very similar.
Synthesis of Lower Valent Molybdenum Oxides by an Ambient Temperature Reduction of Aqueous K2MoO4 by KBH4

Reduction of aqueous K2MoO4 with aqueous KBH4 at ambient temperatures has been investigated systematically to obtain lower valent molybdenum oxides. Several lower valent oxides such as MoO2, Mo4O11...
Qualitative Characterization of Anti-Swirl Gas Dampers

Anti-swirl gas dampers have applications in high-temperature turbomachinery. Nozzles comprising the circumference of the damper inject air against the direction of shaft rotation, providing a force tangential to the rotor surface that acts to damp rotor vibration. The present work involves prediction of experiments by using direct damping and cross-coupled stiffness coefficients given in Vance and Handy (1997) that characterize the rotordynamic performance of an anti-swirl damper. Direct stiffness added at the damper location is vital to representing the changes in critical speeds and the onset and cease of backward whirl given in the experiments. This direct stiffness arises due to the release of air axially across the annulus of the damper. With the addition of this significant direct stiffness, experimental results compare well with the present rotordynamic model. Predictions using the experimentally obtained damping coefficients adequately reproduce the reduction in vibration amplitudes at the critical speeds. However, applying the cross-coupled stiffness coefficients in predictions fails to show increases in the speed at which backward whirl begins and does not reproduce the wrecking instability experienced in the tests. A further study investigates the magnitude of the cross-coupled stiffness coefficient necessary to cause instability in the rotor-damper system.
A note on subsidizing gifts

Abstract Altruistically motivated gifts involve a species of consumption externality. Donors obtain an altruistic benefit from the effect of their gifts on donees' utility but do not take into account that the benefit to donees is itself relevant to social welfare. The level of gift-giving thus will be lower than is optimal. A subsidy can correct this problem, while compulsory transfers (assuming the state lacks information about who is altruistic) and bargaining between donors and donees cannot. The rationale for subsidizing gifts offered here does not depend on whether the donee's activity is a public good (as with gifts for medical research) or whether the transfer tends to equalize the wealth of donors and donees — factors emphasized in the exisitng literature on the subject.
Catalytic asymmetric induction Part 2. Chiral tricarbonyl (η6 arene) chromium (0) complexes as enantioselective catalysts

Abstract A chiral metallocyclic Lewis acid based catalyst system derived from norephedrine is reported. A key stereodirective element emanates from a tricarbonyl chromium (0) group complexed to the aryl ring. The catalysts mediate the addition of dialkyl zinc species to a variety of aldehydes with high enantioselectivity.
Decentralized control for interconnected uncertain systems: extensions to higher-order uncertainties

Abstract Decentralized controller design for large-scale uncertain systems with higher-order uncertainties is investigated. The uncertainties are assumed to be bounded by a known or unknown pth-order polynomial in states. A non-adaptive controller is proposed to handle the case when the pth-order polynomial is known. An adaptive controller is proposed to deal with the unknown case. The effectiveness of the proposed decentralized control schemes is demonstrated by a numerical simulation of two inverted pendulums on carts.
Lithium in the Upper Centaurus Lupus and Lower Centaurus Crux Subgroups of Scorpius-Centaurus

We utilize spectroscopically derived model atmosphere parameters and the Li I λ6104 subordinate line and the λ6708 doublet to derive lithium abundances for 12 members of the Upper Centaurus Lupus and Lower Centaurus Crux subgroups of the Scorpius-Centaurus OB Association. The results indicate any intrinsic Li scatter in our 0.9-1.4 M_☉ stars is limited to ~0.15 dex, consistent with the lack of dispersion in ≥1.0 M_☉ stars in the 100 Myr Pleiades and 30-50 Myr IC 2391 and 2602 clusters. Both ab initio uncertainty estimates and the derived abundances themselves indicate that the λ6104 line yields abundances with equivalent or less scatter than is found from the λ6708 doublet as a result of lower uncertainties for the subordinate feature, a result of low sensitivity to broadening in the subordinate feature. Because non-local thermodynamic equilibrium (NLTE) corrections are less susceptible to changes in surface gravity and/or metallicity for the 6104 A line, the subordinate Li feature is preferred for deriving lithium abundances in young Li-rich stellar association stars with T_(eff) ≥ 5200 K. At these temperatures, we find no difference between the Li abundances derived from the two Li I lines. For cooler stars, having temperatures at which main-sequence dwarfs show abundance patterns indicating overexcitation and overionization, the λ6104-based Li abundances are ~0.4 dex lower than those derived from the λ6708 doublet. The trends of the abundances from each feature with T eff suggest that this difference is due to (near)UV photoionization, which in NLTE preferentially ionizes Li atoms in the subordinate 2p state relative to the 2s resonance line state due to opacity effects. Consequently, this overionization of Li in the 2p state, apparently not adequately accounted for in NLTE corrections, weakens the λ6104 feature in cooler stars. Accordingly, the λ6708-based abundances may give more reliable estimates of the mean Li abundance in cool young stars. Our mean Li abundance, log N(Li) =3.50 ± 0.07 is ~0.2 dex larger than the meteoritic value. While stellar models suggest that Li depletion of at least 0.4 dex, and possibly much larger, should have occurred in our lowest mass star(s), our Li abundances show no decline with decreasing mass indicative of such depletion.
Responses of Plants to Saline Environments

Plants can only grow and reproduce when their cells are bathed by water and permeated by it. Algae and the most active organs of higher plants, the leaves, and the roots, are 85–95 percent water by weight. Desiccation or freezing do not necessarily spell death of all plant cells but slow down to imperceptible rates the metabolic processes of growth and development. Water, then, is of the essence in the functioning of plants.
STEADY STATES FOR ONE-DIMENSIONAL CURVATURE FLOWS

We define two conformal structures on S1 which give rise to a different view of the affine curvature flow and a new curvature flow, the "Q-curvature flow". The steady states of these flows are studied. More specifically, we prove four sharp inequalities, which state the existence of the corresponding extremal metrics.
Benzylic oxidation by sodium bismuthate in acetic acid: A simple method for the synthesis of polycyclic aromatic ketones

Abstract Oxidation of benzylic methylenes in polycyclic systems to the benzylic ketones was carried out with sodium bismuthate in the presence of acetic acid.
Tiros preflight testing and postlaunch evaluation

Eight TIROS satellites have been launched into orbit and have successfully performed the mission for which they were intended. The attainment of the scientific and engineering objectives for these spacecraft is, in large measure, the result of a comprehensive testing and evaluation program. The test phases for flight-qualified pay loads include acceptance, hangar, on-stand precountdown and countdown, and postlaunch evaluation. Several special test fixtures were designed explicitly for this test program. In evaluating the performance of TIROS I, a "magnetic-dipole" effect was discovered which caused precession of the satellite's spin axis. This effect has now been usefully applied for active attitude control on several TIROS satellites and also for the Relay satellites.
Improved synthesis of functionalized 2,2'-bipyrroles.

A series of 2,2‘-bipyrroles has been efficiently synthesized using an improved synthetic approach based on Pd(0)-catalyzed homocoupling of various 2-iodopyrroles. This new synthetic approach takes place at room temperature and in the presence of water. Functional groups such as formyl, ester, and nitrile are able to survive these reaction conditions. Solvents are found to play an important role in this reaction.
Shapes of Elliptic Methane Laminar Jet Diffusion Flames

Buoyant and nonbuoyant shapes of methane flames issued from a 2:1 aspect ratio elliptic tube burner were measured. Nonbuoyant conditions were obtained in the KC-135 micro-gravity research aircraft operated by NASA's Johnson Space Center. A mathematical model based on the extended Burke-Schumann flame theory is developed to predict the flame length of an elliptic burner. The model utilizes Roper's theoretical method for circular burners and extends the analysis for elliptic burners. The predicted flame length using the theoretical model agrees well with experimental measurements. In general for the elliptic burner the nonbuoyant flames are longer than the buoyant flames. However, measured lengths of both buoyant and nonbuoyant flame lengths change proportionally with the volumetric fuel flow rate and support the L vs Q correlation. The maximum flame width measured at buoyant and nonbuoyant conditions also show a proportional relation with the volumetric fuel flow rate. Normalized buoyant and nonbuoyant flame lengths of the elliptic burner correlate (L/d∝Re) with the jet exit Reynolds number and exhibit a higher slope compared to a circular burner. Normalized flame width data show a power correlation (w/d=c Fr") with the jet exit Froude number.
Range counting coresets for uncertain data

We study coresets for various types of range counting queries on uncertain data. In our model each uncertain point has a probability density describing its location, sometimes defined as k distinct locations. Our goal is to construct a subset of the uncertain points, including their locational uncertainty, so that range counting queries can be answered by just examining this subset. We study three distinct types of queries. RE queries return the expected number of points in a query range. RC queries return the number of points in the range with probability at least a threshold. RQ queries returns the probability that fewer than some threshold fraction of the points are in the range. In both RC and RQ coresets the threshold is provided as part of the query. And for each type of query we provide coreset constructions with approximation-size tradeoffs. We show that random sampling can be used to construct each type of coreset, and we also provide significantly improved bounds using discrepancy-based approaches on axis-aligned range queries.
α-Keto heterocycle inhibitors of fatty acid amide hydrolase: carbonyl group modification and α-substitution

Two sets of novel analogues of the recently disclosed α-keto heterocycle inhibitors of fatty acid amide hydrolase (FAAH), the enzyme responsible for regulation of endogenous oleamide and anandamide, were synthesized and evaluated in order to clarify a role of the electrophilic carbonyl group and structural features important for their activity. Both the electrophilic carbonyl and the degree of α-substitution markedly affect inhibitor potency.
Interactive ray tracing

We examine a rendering system that interactively ray traces an image on a conventional multiprocessor. The implementation is "brute force" in that it explicitly traces rays through every screen pixel, yet pays careful attention to system resources for acceleration. The design of the system is described, along with issues related to material models, lighting and shadows, and frameless rendering. The system is demonstrated for several different types of input scenes.
Estimation of upper limits using a Poisson statistic

Abstract Bayesian, classical, and extended maximum-likelihood approaches to estimation of upper limits in experiments with small numbers of signal events are surveyed. The discussion covers only experiments whose outcomes are well described by a Poisson statistic. A new approach is proposed, based on the statistical significance of a signal rather than on the number of events in the signal region. Application of these techniques is illustrated using a toy model.
Psychiatric training in medicine residencies: current needs, practices, and satisfaction.

The purpose of this study was to determine the current level of psychiatric training in internal medicine residencies, satisfaction with this training, and perceived need, if any, for more training. Surveys were mailed to all training directors of accredited primary care (N = 178) and categorical (N = 410) internal medicine residencies in the United States; 110 primary care (62%) and 238 categorical (58%) training directors returned the surveys. Seventy-five percent of categorical and 66% of primary care training directors thought their program should spend more time on psychiatric disorders. For all categories of psychiatric disorder, training intensity was greater and satisfaction with training higher in the primary care programs, but less than half of the directors were satisfied with their current level of training, e.g., 33% of categorical and 47% of primary care directors were satisfied with their residents training concerning depression. Training in somatoform disorders, psychotropic drugs, and office psychotherapy were most frequently identified as deficient. The most favored additions to the curriculum were psychiatric consultants in medical clinics and on medical wards. Although most outpatient care for psychiatric disorders is given by primary care physicians, internal medicine training directors perceive current levels of training in their residencies as inadequate. Innovative collaborations between medicine and psychiatry departments will be necessary if treatment of psychiatric disorders in primary care is to be improved.
Hormonal steroids and sexual communication in primates.

Abstract Under laboratory conditions, pairs of rhesus monkeys show at least four different patterns of sexual behavior in relation to the stage of the menstrual cycle. The most interesting of these is characterized by a distinct mid-cycle peak followed by a secondary pre-menstrual rise. High doses of progesterone administered to ovariectomized females receiving estrogen replacement treatment resulted in a marked reduction of the sexual behavior of the pair either because the female refused the male or because the male made fewer mounting attempts. Males were shown by operant conditioning and nose-blocking procedures to detect the hormonal status of theier female partners by olfactory mechanisms. Shortchain fatty acids in the vaginal secretions of females were found to be responsible for this effect. The same acids have been shown to be normal constituents of human vaginal secretions, and levels were highest in the late follicular phase but declined progressively during the luteal phase of the menstrual cycle. In women taking oral contraceptives, levels of volatile acids in the secretions were lower than normal and rhythmic production during the menstrual cycle was abolished.
Multiprocessor FFT methods

Proceeding first by experiment and then by analysis, the problem of implementing FFT algorithms on a shared memory multiprocessor is investigated. Several algorithms for performing a single FFT and multiple FFTs are implemented and compared on the Denelcor HEP computer. These algorithms are then analyzed using performance models which reproduce the experimental timing curves. For both the single and multiple FFT a clear choice of superior algorithms can be made. These algorithms are expected to be useful and to preserve their performance characteristics on other shared memory multiprocessors.
Identification of a Fundamental Transition in a Turbulently Supported Interstellar Medium

The interstellar medium (ISM) in star-forming galaxies is a multiphase gas in which turbulent support is at least as important as thermal pressure. Sustaining this configuration requires continuous radiative cooling, such that the overall average cooling rate matches the decay rate of turbulent energy into the medium. Here we carry out a set of numerical simulations of a stratified, turbulently stirred, radiatively cooled medium, which uncover a fundamental transition at a critical one-dimensional turbulent velocity of ≈35 km s–1. At turbulent velocities below ≈35 km s–1, corresponding to temperatures below 105.5 K, the medium is stable, as the time for gas to cool is roughly constant as a function of temperature. On the other hand, at turbulent velocities above the critical value, the gas is shocked into an unstable regime in which the cooling time increases strongly with temperature, meaning that a substantial fraction of the ISM is unable to cool on a turbulent dissipation timescale. This naturally leads to runaway heating and ejection of gas from any stratified medium with a 1D turbulent velocity above ≈35 km s–1, a result that has implications for galaxy evolution at all redshifts.
Solar sailcraft motion in Sun-Earth-Moon space with application to lunar transfer from geosynchronous orbit

Abstract A three-dimensional model of the dynamics of a solar sailcraft in the Earth-Sun-Moon system is presented. The model includes the following features: (1) the derivation of a unit vector describing the direction of the resultant radiation force for a spectrally reflecting sail; (2) the derivation of equations of motion for the sailcraft and the Moon in spherical co-ordinates; (3) the derivation of generalized equations for the initial conditions of the sailcraft in terms of orbit parameters; and (4) the development of attitude control equations for the sail. A computer program based on the above model which includes a search routine is described. The program is used, together with a strategy for searching through a four-dimensional parametric space of initial orbit parameters, to investigate the problem of transfer to the Moon from a geosynchronous orbit. Results are obtained for two types of lunar encounters and three values of the sailcraft's area to mass ratio. Plots are presented for the orbits of the sailcraft and the Moon for the lunar encounter and for post-encounter sailcraft trajectories. It is found that a close flyby of the Moon can take place in 63–67 days for an area to mass ratio of 100 and that the type of lunar encounter can result in significantly different post-encounter sailcraft trajectories.
Approximation algorithms for multiple sequence alignment

We consider the problem of aligning of k sequences of length n. The cost function is sum of pairs, and satisfies triangle inequality. Earlier results on finding approximation algorithms for this problem are due to Gusfield, 1991, who achieved an approximation ratio of 2 − 2/k, and Pevzner, 1992, who improved it to 2 − 3/k. We generalize this approach to assemble an alignment of k sequences from optimally aligned subsets of l<k sequences to obtain an improved performance guarantee. For arbitrary l<k, we devise deterministic and randomized algorithms yielding performance guarantees of 2−l/k. For fixed l, the running times of these algorithms are polynomial in n and k.
Does Professor Quality Matter? Evidence from Random Assignment of Students to Professors

In primary and secondary education, measures of teacher quality are often based on contemporaneous student performance on standardized achievement tests. In the postsecondary environment, scores on student evaluations of professors are typically used to measure teaching quality. We possess unique data that allow us to measure relative student performance in mandatory follow‐on classes. We compare metrics that capture these three different notions of instructional quality and present evidence that professors who excel at promoting contemporaneous student achievement teach in ways that improve their student evaluations but harm the follow‐on achievement of their students in more advanced classes.
Natural little hierarchy from a partially goldstone twin Higgs

We construct a simple theory in which the fine-tuning of the standard model is significantly reduced. Radiative corrections to the quadratic part of the scalar potential are constrained to be symmetric under a global U(4) × U(4)' symmetry due to a discrete Z2 ``twin'' parity, while the quartic part does not possess this symmetry. As a consequence, when the global symmetry is broken the Higgs fields emerge as light pseudo-Goldstone bosons, but with sizable quartic self-interactions. This structure allows the cutoff scale, Λ, to be raised to the multi-TeV region without significant fine-tuning. In the minimal version of the theory, the amount of fine-tuning is about 15% for Λ = 5 TeV, while it is about 30% in an extended model. This provides a solution to the little hierarchy problem. In the minimal model, the ``visible'' particle content is exactly that of the two Higgs doublet standard model, while the extended model also contains extra vector-like fermions with masses ≈ (1 ~ 2) TeV. At the LHC, our minimal model may appear exactly as the two Higgs doublet standard model, and new physics responsible for cutting off the divergences of the Higgs mass-squared parameter may not be discovered. Several possible processes that may be used to discriminate our model from the simple two Higgs doublet model are discussed for the LHC and for a linear collider.
What are the potential benefits of including latent storage in common wallboard

Previous work has shown that wallboard can be successfully manufactured to contain up to 30% phase change material (PCM), or wax, thus enabling this common building material to serve as a thermal energy storage device. This material was analyzed for passive solar applications and found to save energy with a reasonable pay-back time period. Further evaluations of the wallboard are reported in this paper. This analysis looks at potential applications of PCM wallboard as a load management device and as a comfort enhancer. Results show that the wallboard is ineffective in modifying the comfort level but can provide significant load management relief with no energy penalty. Modifications to typical heating and air-conditioning control strategies were necessary for successful load management.
PSPACE-completeness of sliding-block puzzles and other problems through the nondeterministic constraint logic model of computation

We present a nondeterministic model of computation based on reversing edge directions in weighted directed graphs with minimum in-flow constraints on vertices. Deciding whether this simple graph model can be manipulated in order to reverse the direction of a particular edge is shown to be PSPACE-complete by a reduction from Quantified Boolean Formulas. We prove this result in a variety of special cases including planar graphs and highly restricted vertex configurations, some of which correspond to a kind of passive constraint logic. Our framework is inspired by (and indeed a generalization of) the "Generalized Rush Hour Logic" developed by Flake and Baum [Theoret. Comput. Sci. 270(1-2) (2002) 8951.We illustrate the importance of our model of computation by giving simple reductions to show that several motion-planning problems are PSPACE-hard. Our main result along these lines is that classic unrestricted sliding-block puzzles are PSPACE-hard, even if the pieces are restricted to be all dominoes (1 × 2 blocks) and the goal is simply to move a particular piece. No prior complexity results were known about these puzzles. This result can be seen as a strengthening of the existing result that the restricted Rush HourTM puzzles are PSPACE-complete [Theoret. Comput. Sci. 270(1-2) (2002) 895], of which we also give a simpler proof. We also greatly strengthen the conditions for the PSPACE-hardness of the Warehouseman's Problem [Int. J. Robot. Res. 3(4) (1984) 76], a classic motion-planning problem. Finally, we strengthen the existing result that the pushing-blocks puzzle Sokoban is PSPACE-complete [In: Proc. Internat. Conf. on Fun with Algorithms, Elba, Italy, June 1998, pp. 65-76.], by showing that it is PSPACE-complete even if no barriers are allowed.
Spinal Cord Stimulation

Over 25 years ago, electrical stimulation of the spinal cord using implanted electrodes was introduced as a reversible technique for the management of chronic, intractable pain.1 As a reversible alternative to ablative procedures, this prototypical “neuroaugmentative” procedure was appealing; but the indications for neurosurgical intervention for chronic, benign pain were not widely understood at that time. As the behavioral and psychological issues in pain management have become more widely appreciated, and as programs specializing in chronic pain have proliferated, the process of patient selection has been refined considerably. At the same time, there have been major improvements in implantable spinal cord stimulation devices, which have significantly enhanced clinical results.2,3
A thermodynamically consistent non-ideal stochastic hard-sphere fluid

A grid-free variant of the direct simulation Monte Carlo (DSMC) method is proposed, named the isotropic DSMC (I-DSMC) method, that is suitable for simulating dense fluid flows at molecular scales. The I-DSMC algorithm eliminates all grid artifacts from the traditional DSMC algorithm; it is Galilean invariant and microscopically isotropic. The stochastic collision rules in I-DSMC are modified to yield a non-ideal structure factor that gives consistent compressibility, as first proposed by Donev et al (2008 Phys. Rev. Lett. 101 075902). The resulting stochastic hard-sphere dynamics (SHSD) fluid is empirically found to have the same pair correlation function as a deterministic Hamiltonian system of penetrable spheres interacting with a linear core pair potential, well described by the hypernetted chain (HNC) approximation. We apply a stochastic Enskog kinetic theory to the SHSD fluid to obtain estimates for the transport coefficients that are in excellent agreement with particle simulations over a wide range of densities and collision rates. The fluctuating hydrodynamic behavior of the SHSD fluid is verified by comparing its dynamic structure factor against theory based on the Landau–Lifshitz Navier–Stokes equations. We also study the Brownian motion of a nanoparticle suspended in an SHSD fluid and find a long-time power-law tail in its velocity autocorrelation function consistent with hydrodynamic theory and molecular dynamics calculations.
Characteristics Of Near-Millimeter Wave Propagation In Snow

AbstractResults of an investigation of propagation in snow at 96, 140, and 225 GHz are reported.Measurements were made with the Harry Diamond Laboratories near -millimeter wave mobilemeasurement facility in snow with mass concentrations up to 0.9 gm /m3. For each frequencya correlation was found to exist between attenuation coefficients and snow mass concentra- tion. Snow back tatter cross sections per unit volume at 96 GHz were found to range between1 and 7 x 10-5 ma /m3 for snow concentrations between 0.1 and 0.6 gm /m3.IntroductionThere has been an increasing interest during the past several years in systems that oper-ate in the near -millimeter wavelength region (3.2 to 0.3 mm). Within this spectral range,limited component availability and propagation considerations have resulted in system de-signers focussing their attention on those frequencies lying within the atmospheric windowsabout 95, 140, and 225 GHz. A serious problem for the system designers has been the lack ofdata on propagation characteristics at these frequencies, not only for clear air but alsofor adverse weather conditions. In this paper we wish to report on near -millimeter wavepropagation measurements for one adverse weather condition: snow. Attenuation coefficientswere determined at 96, 140, and 225 GHz for snow with varying mass concentrations at a test
The uBVI Photometric System. I. Motivation, Implementation, and Calibration

This paper describes the design principles for a CCD-based photometric system that is highly optimized for ground-based measurement of the size of the Balmer jump in stellar energy distributions. It is shown that, among ultraviolet filters in common use, the Thuan-Gunn u filter is the most efficient for this purpose. This filter is combined with the standard Johnson-Kron-Cousins B, V, and I bandpasses to constitute the uBVI photometric system. Model stellar atmospheres are used to calibrate color-color diagrams for the uBVI system in terms of the fundamental stellar parameters of effective temperature, surface gravity, and metallicity. The u - B index is very sensitive to log g, but also to [Fe/H]. It is shown that an analog of the Stromgren c1 index, defined as (u - B) - (B - V), is much less metallicity dependent but still sensitive to log g. The effect of interstellar reddening on u - B is determined through synthetic photometric calculations, and practical advice is given on dealing with flat fields, atmospheric extinction, the red leak in the u filter, and photometric reductions. The uBVI system offers a wide range of applicability in detecting stars of high luminosity in both young (yellow supergiants) and old (post-AGB stars) populations, in using stars of both types as standard candles to measure extragalactic distances with high efficiency, and in exploring the horizontal branch in globular clusters. In many stellar applications, it can profitably replace the classical UBVI system. Paper II in this series will present a network of well-calibrated standard stars for the uBVI system.
Bulk flow and shear moments of the SFI++ survey

We find the nine bulk flow and shear moments from the SFI++ survey, as well as for subsamples of group and field galaxies. We constrain the velocity power spectrum shape parameter r in linear theory using these moments. A likelihood function for r was found after marginalizing over the power spectrum amplitude σ8Ω 0.6 m using constraints obtained from comparisons between redshift surveys and peculiar velocity data. We have estimated the velocity noise σ* from the data since without it our results may be biased. We also performed a statistical analysis of the difference between the field and group catalogues and found that the results from each reflect the same underlying large-scale flows. We found that we can constrain the power spectrum shape parameter to be Γ = 0.15 +0.18 -0.08 for the groups catalogue and r = 0.09 +0.04 -0.04 for the field galaxy catalogue in fair agreement with the value from Wilkinson Microwave Anisotropy Probe.
Spatial Scan Density Estimates

The detection and identification of regions of interest in spatial or temporal data is a common concern in automatic target recognition. One approach to region-of-interest identification involves the use of spatial scan statistics. A difficulty arises due to competing concerns: Small scan windows are required for potentially small targets, but larger scan windows are necessary to improve the accuracy of the detector. When the scan statistics are mixture-model density estimates, a borrowed strength profile likelihood approach is shown to be superior to conventional likelihood estimators. We investigate these spatial scan density estimates on example imagery from an unmanned aerial vehicle.
Graph mining: laws, generators and tools

How do graphs look like? How do they evolve over time? How can we generate realistic-looking graphs? We review some static and temporal 'laws,' and we describe the "Kronecker" graph generator, which naturally matches all of the known properties of real graphs. Moreover, we present tools for discovering anomalies and patterns in two types of graphs, static and time-evolving. For the former, we present the 'CenterPiece' subgraphs (CePS), which expects q query nodes (eg., suspicious and finds the node that is best connected to all q of them (eg., the master mind of a criminal group). We also show how to compute CenterPiece subgraphs efficiently. For the time evolving graphs, we present tensor-based methods, and apply them on real data, like the DBLP author-paper dataset, where they are able to find natural research communities, and track their evolution. Finally, we also briefly mention some results on influence and virus propagation on real graphs, as well as on the emerging map/reduce approach and its impact on large graph mining.
Solvent-free synthesis of amides from non-enolizable esters and amines using microwave irradiation

Abstract An efficient solid state synthesis of amides is described from non-enolizable esters and amines using potassium tert-butoxide under microwave irradiation conditions.
Approximation algorithms for restless bandit problems

The restless bandit problem is one of the most well-studied generalizations of the celebrated stochastic multi-armed bandit (MAB) problem in decision theory. In its ultimate generality, the restless bandit problem is known to be PSPACE-Hard to approximate to any nontrivial factor, and little progress has been made on this problem despite its significance in modeling activity allocation under uncertainty.In this article, we consider the Feedback MAB problem, where the reward obtained by playing each of n independent arms varies according to an underlying on/off Markov process whose exact state is only revealed when the arm is played. The goal is to design a policy for playing the arms in order to maximize the infinite horizon time average expected reward. This problem is also an instance of a Partially Observable Markov Decision Process (POMDP), and is widely studied in wireless scheduling and unmanned aerial vehicle (UAV) routing. Unlike the stochastic MAB problem, the Feedback MAB problem does not admit to greedy index-based optimal policies.We develop a novel duality-based algorithmic technique that yields a surprisingly simple and intuitive (2+ϵ)-approximate greedy policy to this problem. We show that both in terms of approximation factor and computational efficiency, our policy is closely related to the Whittle index, which is widely used for its simplicity and efficiency of computation. Subsequently we define a multi-state generalization, that we term Monotone bandits, which remains subclass of the restless bandit problem. We show that our policy remains a 2-approximation in this setting, and further, our technique is robust enough to incorporate various side-constraints such as blocking plays, switching costs, and even models where determining the state of an arm is a separate operation from playing it.Our technique is also of independent interest for other restless bandit problems, and we provide an example in nonpreemptive machine replenishment. Interestingly, in this case, our policy provides a constant factor guarantee, whereas the Whittle index is provably polynomially worse.By presenting the first O(1) approximations for nontrivial instances of restless bandits as well as of POMDPs, our work initiates the study of approximation algorithms in both these contexts.
Design of New Superconducting Materials, and Point-Contact Spectroscopy as a Probe of Strong Electron Correlations

At this centenary of the discovery of superconductivity, the design of new and more useful superconductors remains as enigmatic as ever. These materials play crucial roles both for fundamental science and applications, and they hold great promise in addressing our global energy challenge. The recent discovery of a new class of high-temperature superconductors has made the community more enthusiastic than ever about finding new superconductors. Historically, these discoveries were almost completely guided by serendipity, and now, researchers in the field have grown into an enthusiastic global network to find a way, together, to predictively design new superconductors. After a short history of discoveries of superconducting materials, we share our own guidelines for searching for high-temperature superconductors. Finally, we show how point-contact spectroscopy (PCS) is used to detect strong correlations in the normal state, with a focus on the normal state region of the Fe-based superconductors, defining a new region in the phase diagram of Ba(Fe1−x Co x )2As2.
Formal and Operative Rules in Overliquidation Per Se Cases

Liquidated damages clauses are typically upheld where the damages are of a type that will be difficult to ascertain, and where the parties have made a reasonable estimate of the potential damages. A unique but not entirely rare phenomenon the author calls overliquidation per se occurs when, fortuitously, no damage is sustained as a result of a contract breach. The applicable formal rule of law, the penalty doctrine, is quite ineffective in resolving this interesting contract dilemma. So what do judges do? What should they do? On the one hand, strong freedom of contract principles dictate enforcement; while on the other, the equally well entrenched principle of just compensation prescribes non-enforcement. By analyzing the modern overliquidation per se case law, the author is able to look beyond the formal rule of law to the functional 'operative rules,' a series of sometimes overlapping questions that explain the cases. This original analysis permits the development and articulation of a new formal rule for overliquidation per se cases.
Hydroxy-directed hydroaluminations: A stereoselective approach to cycloalkanols from β-aryl enones

Abstract Various aryl substituted enones are reduced using lithium aluminum hydride to afford sterioselectively trans substituted alkanols. Mechanistic studies demonstrate 1,2 addition followed by hydroxy-directed hydroalumination of the conjugated styryl unit.
A new layered metal–organic framework as a promising heterogeneous catalyst for olefin epoxidation reactions

A new layered MOF material [Co(Hoba)2·2H2O] (1) (H2oba = 4,4′-oxybis(benzoic acid)) has been synthesized and used as a highly recyclable heterogeneous catalyst for olefin epoxidation reactions. Both high conversion (96%) and high selectivity of epoxide products (96%) are achieved.
Comparison of atmospheric temperatures obtained through infrared sounding and radio occultation by Mars Global Surveyor

[1] Mars Global Surveyor monitors temperatures in the Martian atmosphere through infrared sounding by the Thermal Emission Spectrometer (TES) as well as Radio Science (RS) occultation experiments. We report results from extensive comparisons of TES nadir and RS temperature profiles, focusing on data obtained under conditions that allow nearly simultaneous measurements at the same location and local time. We analyzed data from 13 intervals with durations of 7–19 sols that sample latitudes of 62°–85°N during midspring through early autumn. Our results generally confirm the accuracy and reliability of both sets of observations. We find particularly good agreement between the zonal variations of temperature observed by the two instruments. Zonally averaged temperature profiles agree to within ∼2 K at pressures <400 Pa. Results are less satisfactory at 610 Pa, where the TES retrievals are persistently warmer by a margin of 2–8 K. These discrepancies arise primarily from a wide disparity in vertical resolution. The RS measurements reveal subtle but significant vertical variations of temperature, particularly at low altitudes, that the TES is unable to resolve. For the range of latitudes and seasons considered here, the most serious consequence is that vertical gradients of temperature deduced from TES profiles are unreliable in the lowest scale height above the surface. Our analysis also shows that the RS profiles from selected intervals might contain a low-altitude bias due to the unmodeled effect of water vapor. These results should contribute to a more confident characterization of Martian climate.
Compensating a String PDE in the Actuation or Sensing Path of an Unstable ODE

How to control an unstable linear system with a long pure delay in the actuator path? This question was resolved using 'predictor' or 'finite spectrum assignment' designs in the 1970s. Here we address a more challenging question: How to control an unstable linear system with a wave partial differential equation (PDE) in the actuation path? Physically one can think of this problem as having to stabilize a system to whose input one has access through a string. The challenges of overcoming string/wave dynamics in the actuation path include their infinite dimension, finite propagation speed of the control signal, and the fact that all of their (infinitely many) eigenvalues are on the imaginary axis. In this technical note we provide an explicit feedback law that compensates the wave PDE dynamics at the input of an linear time-invariant ordinary differential equation and stabilizes the overall system. In addition, we prove robustness of the feedback to the error in a priori knowledge of the propagation speed in the wave PDE. Finally, we consider a dual problem where the wave PDE is in the sensing path and design an exponentially convergent observer.
Knowledge complementarity and innovation

This paper uses an innovation production fi.mc- tion to relate the presence of geographically-mediated com- plementary knowledge resources to the innovative activity of small and large firms. The empirical results suggest that small firm innovation appears to benefit from the presence of external institutions and resources. Although large firm innovative activity benefits from the presence of knowledge resources, location appears to be especially beneficial to small firm innovative activity.
EIGHTH-ORDER IMAGE MASKS FOR TERRESTRIAL PLANET FINDING

We describe a new series of band-limited image masks for coronagraphy that are insensitive to tip-tilt errors and other low spatial frequency optical aberrations. For a modest cost in throughput, these "eighth-order" masks would allow the Terrestrial Planet Finder Coronagraph (TPF-C) to operate with a pointing accuracy no better than that of the Hubble Space Telescope. We also provide eighth-order notch filter masks that offer the same robustness to pointing errors combined with more manageable construction tolerances: binary masks and sampled graded masks with moderate optical density requirements.
Organic Base‐Catalyzed Stereoselective Isomerizations of 4‐Hydroxy‐4‐phenyl‐but‐2‐ynoic Acid Methyl Ester to (E)‐ and (Z)‐4‐Oxo‐4‐phenyl‐but‐2‐enoic Acid Methyl Esters

Abstract We have developed a 1,4‐diazabicyclo[2.2.2]octane (DABCO)‐catalyzed isomerization of 4‐hydroxy‐4‐phenyl‐but‐2‐ynoic acid methyl ester to (E)‐4‐oxo‐4‐phenyl‐but‐2‐enoic acid methyl ester and an N,N‐diisopropylethylamine‐catalyzed isomerization of the same substrate to (Z)‐4‐oxo‐4‐phenyl‐but‐2‐enoic acid methyl ester.
Finite automorphisms of negatively curved Poincaré duality groups

In this paper, we show that if G is a finite p-group (p prime) acting by automorphisms on a δ-hyperbolic Poincare Duality group over \( \mathbb{Z} \), then the fixed subgroup is a Poincare Duality group over \( \mathbb{Z}_p \). We also provide a family of examples to show that the fixed subgroup might not be a Poincare Duality group over \( \mathbb{Z} \). In fact, the fixed subgroups in our examples even fail to be duality groups over \( \mathbb{Z} \).
Low-temperature pressure broadening in the ν3 band of methane in the presence of para and ortho hydrogen

Abstract High-accuracy measurements of the pressure broadening of the methane ν 3 band have been made in the presence of different concentrations of para and ortho hydrogen. No appreciable difference has been found.