cssi/SciSciGPT-SciSciNet huggingface dataset:
Isotopic splittings and OPE in B→D semileptonic decays

Abstract It is shown that the kinematical difference in the decays B − →D 0 l ν and B 0 →D + l ν due to the isotopic mass splittings of the B and D mesons is compensated in the total decay rate by an appropriate difference in the lepton spectra. Thus there is no effect on the total decay rates in the linear order in the isotopic mass splittings, as required by the general consideration based on the operator product expansion. Although phenomenologically the isotopic difference in the spectra amounts to at most about 1%, in the theoretical aspect this effect can be viewed as an additional illustration of how the general OPE results emerge from the properties of exclusive channels.
NEAR-CONTEMPORANEOUS OPTICAL SPECTROSCOPIC AND INFRARED PHOTOMETRIC OBSERVATIONS OF CANDIDATE HERBIG Ae/Be STARS IN THE MAGELLANIC CLOUDS

We present near-IR (J, H, Ks) photometry for 27 of the 28 candidate Herbig Ae/Be stars in the Small and Large Magellanic Clouds (SMC and LMC) identified via the EROS1 and EROS2 surveys as well as near-contemporaneous optical (Hα) spectroscopy for 21 of these 28 candidates. Our observations extend previous efforts to determine the evolutionary status of these objects. We compare the IR brightness and colors of a subset of our sample with archival ground-based IR data and find evidence of statistically significant photometric differences for EROS LMC HAeBe candidates (ELHC) 5, 7, 12, 18, and 21 in one or more filters. In all cases, these near-IR photometric variations exhibit a gray color as compared to earlier epoch data. The ~1 mag IR brightening and minimal change in the Hα emission strength we observe in ELHC 7 is consistent with previous claims that it is a UX Ori type HAe/Be star, which is occasionally obscured by dust clouds. We also detect a ~1 mag IR brightening of ELHC 12, but find little evidence of a similar large-scale change in its Hα line strength, suggesting that its behavior could also be caused by a UX Ori-like event. The ~0.5 mag IR variability we observe for ELHC 21, which also exhibited little evidence of a change in its Hα emission strength, could conceivably be caused by a major recent enhancement in the density of the inner disk region of a classical Be star. We also report the first near-IR photometry for two EROS SMC HAeBe Candidates (ESHC) stars and the first Hα spectroscopy for one ELHC and five ESHC stars. Although Hα emission is detected in all of these new observations, they do not exhibit a strong near-IR excess. It is therefore possible that many of these objects may be classical Be stars rather than Herbig Ae/Be stars.
Kinetics and Mechanism of the Epoxidation of Alkyl-Substituted Alkenes by Hydrogen Peroxide, Catalyzed by Methylrhenium Trioxide

Epoxidations of alkyl-substituted alkenes, with hydrogen peroxide as the oxygen source, are catalyzed by CH(3)ReO(3) (MTO). The kinetics of 28 such reactions were studied in 1:1 CH(3)CN-H(2)O at pH 1 and in methanol. To accommodate the different requirements of these reactions, (1)H-NMR, spectrophotometric, and thermometric techniques were used to acquire kinetic data. High concentrations of hydrogen peroxide were used, so that diperoxorhenium complex CH(3)Re(O)(eta(2)-O(2))(2)(H(2)O), B, was the only predominant and reactive form of the catalyst. The reactions between B and the alkenes are about 1 order of magnitude more rapid in the semiaqueous solvent than in methanol. The various trends in reactivity are medium-independent. The rate constants for B with the aliphatic alkenes correlate closely with the number of alkyl groups on the olefinic carbons. The reactions become markedly slower when electron-attracting groups, such as halo, hydroxy, cyano, and carbonyl, are present. The rate constants for catalytic epoxidations with B and those reported for the stoichiometric reactions of dimethyldioxirane show very similar trends in reactivity. These findings suggest a concerted mechanism in which the electron-rich double bond of the alkene attacks a peroxidic oxygen of B. These data, combined with those reported for the epoxidation of styrene (a term intended to include related molecules with ring and/or aliphatic substituents) by B and by the monoperoxo derivative of MTO, suggest that all of the rhenium-catalyzed epoxidations occur by a common mechanism. The geometry of the system at the transition state can be inferred from these data, which suggest a spiro arrangement.
NEW DISORDER INDUCED PHASE TRANSITIONS OF CLASSICAL RARE GASES IN POROUS VYCOR GLASS

We report the results of x-ray diffraction studies of Ar and Kr confined in Vycor glass. The freezing and melting temperatures of both Ar and Kr were suppressed well below their bulk freezing points. On solidification, both samples crystallized in a disordered hexagonal close packed structure similar to that observed in molecular dynamics simulations of confined solids. A new solid-solid phase transition is observed at a reduced temperature of ${T/T}_{f}\ensuremath{\approx}0.5$ when confined to Vycor. Below this temperature the disordered hexagonal closed packed structure coexists with the fcc structure.
Non-linear plasma wake growth of electron holes

An object's wake in a plasma with small Debye length that drifts across the magnetic field is subject to electrostatic electron instabilities. Such situations include, for example, the moon in the solar wind and probes in magnetized laboratory plasmas. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the plasma wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of electron to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that electron holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable size, beyond which their uncontrolled growth disrupts the ions. The hole growth calculations provide a quantitative prediction of hole profile and size evolution. Hole growth appears to explain the observations of recent particle-in-cell simulations.
Cooperative Defense Against Pollution Attacks in Network Coding Using SpaceMac

Intra-session network coding is inherently vulnerable to pollution attacks. In this paper, first, we introduce a novel homomorphic MAC scheme called SpaceMac, which allows an intermediate node to verify whether received packets belong to a specific subspace, even if the subspace is expanding over time. Then, we use SpaceMac as a building block to design a cooperative scheme that provides complete defense against pollution attacks: (i) it can detect polluted packets early at intermediate nodes, and (ii) it can identify the exact location of all, even colluding, attackers, thus making it possible to eliminate them. Our scheme is cooperative: parents and children of any node cooperate to detect any corrupted packets sent by the node, and nodes in the network cooperate with a central controller to identify the exact location of all attackers. We implement SpaceMac in both C/C++ and Java as a library, which we make publicly available. Our evaluation on both a PC and an Android device shows that the SpaceMac algorithms can be computed quickly and efficiently and that our cooperative defense scheme has low computation overhead and significantly lower communication overhead than those of state-of-the-art schemes.
Cooperative self-propulsion of active and passive rotors

Using minimal models for low Reynolds number passive and active rotors in a fluid, we characterize the hydrodynamic interactions among rotors and the resulting dynamics of a pair of interacting rotors. This allows us to treat in a common framework passive or externally driven rotors, such as magnetic colloids driven by a rotating magnetic field, and active or internally driven rotors, such as sperm cells confined at boundaries. The hydrodynamic interaction of passive rotors is known to contain an azimuthal component ∼1/r2 to dipolar order that can yield the recently studied “cooperative self-propulsion” of a pair of rotors of opposite vorticity. It is also known, although not widely appreciated, that this interaction is identically zero for active rotors as a consequence of torque balance. In this paper we show that a ∼1/r4 azimuthal component of the interaction arises in active systems to octupolar order. This is a new result that allows us to discuss the dynamic behavior of pairs of passive and active interacting rotors in a unified manner and to show that cooperative self-propulsion, although weaker, can also occur for pairs of active rotors.
Adapting a Navier-Stokes code to the ICL-DAP

This is a report of the results of an experiment: to adapt a Navier-Stokes code, originally developed on a serial computer, to concurrent processing on the ICL Distributed Array Processor (DAP). In this paper the algorithm used in solving the Navier-Stokes equations is briefly described. The architecture of the DAP and DAP Fortran is also described. The modifications of the algorithm so as to fit the DAP are given and discussed. Finally, performance results are given and conclusions are drawn.
iSee: interactive scenario explorer for online tournament games

Fantasy games, in which players compete to correctly predict real-world outcomes in sports, entertainment, and politics, have grown in popularity and now represent a significant portion of online gaming. Pick'em pools, also known as office pools, are a fantasy game specifically focused on tournament-style competitions such as the "March Madness" NCAA basketball championship. Pick'em pool players often spend significant time trying to understand the current state of competition and to anticipate future events that may significantly affect their performance within the pool. Unfortunately, the combinatorial nature of the outcome space makes these tasks extremely challenging, and intuition is often a highly inaccurate guide. In this paper we present iSee, a system that allows players to make these complex calculations and inferences. We describe a variety of interface options for the interactive presentation of tournament outcome visualizations. We also describe in detail the implementation of a set of algorithms for reliably projecting player performance and distilling the complex outcome space to a number of key scenarios. Finally, we report on a pilot study soliciting user feedback on the system.
Chirality sensing using stereodynamic probes with distinct electronic circular dichroism output

Circular dichroism (CD) spectroscopy is one of the most useful techniques for the stereochemical analysis of chiral biopolymers and fine chemicals. It has become invaluable for the assignment of the absolute configuration, the study of conformational isomers, and the determination of racemization kinetics of CD active chiral compounds. Molecular interactions between a nonracemic chiral substrate and a chromophoric, CD-silent probe that is achiral or exists as a racemic mixture of rapidly interconverting enantiomeric conformations or configurations can induce a strong, characteristic chiroptical readout. A covalent or noncovalent binding event that coincides with a well-defined asymmetric induction process can effectively imprint the chiral information of the substrate on the stereodynamic sensor and thus generate intense Cotton effects in the UV region of the latter. The probe can thus function as a stereochemical reporter unit and analysis of the CD spectrum often provides accurate information about the absolute configuration and enantiomeric composition of the substrate used. In this review, recent developments in circular dichroism analysis of chiral compounds with stereodynamic probes are described and particular emphasis is given to sensor design, chiral induction processes and applications scope.
Student Evaluations of Teachers

Rodin and Rodin point out that there are two ways of judging teaching through students—ascertaining how much students have learned and obtaining student evaluations of teacher effectiveness. Some commonly accepted notions regarding student evaluations are challenged in this article, which comments on the results obtained in a number of studies. The authors suggest that “students are less than perfect judges of teaching effectiveness”—at least if teaching effectiveness is measured by how much students learn. This paper, reprinted from Science, helps to set the stage for the remaining articles in this issue.
Synthetic design of crystalline inorganic chalcogenides exhibiting fast-ion conductivity

Natural porous solids such as zeolites are invariably formed with inorganic cations such as Na+ and K+ (refs 1, 2). However, current research on new porous materials is mainly focused on the use of organic species as either structure-directing or structure-building units; purely inorganic systems have received relatively little attention in exploratory synthetic work3,4,5,6,7,8,9. Here we report the synthesis of a series of three-dimensional sulphides and selenides containing highly mobile alkali metal cations as charge-balancing extra-framework cations. Such crystalline inorganic chalcogenides integrate zeolite-like architecture with high anionic framework polarizability and high concentrations of mobile cations. Such structural features are particularly desirable for the development of fast-ion conductors10. These materials demonstrate high ionic conductivity (up to 1.8 × 10-2 ohm-1 cm-1) at room temperature and moderate to high humidity. This synthetic methodology, together with novel structural, physical and chemical properties, may lead to the development of new microporous and open-framework materials with potential applications in areas such as batteries, fuel cells, electrochemical sensors and photocatalysis.
Molecular association at the microscopic level

For the molecular equilibrium A + B ⇔ AB occurring in a dilute solution or gas, the two-particle Helmholtz free energy, W, is used to evaluate the association constant, KAB, which, for ionic A and ...
Self-similar shear thickening behavior in CTAB/NaSal surfactant solutions

The effect of salt concentration Cs on the critical shear rate γc required for the onset of shear thickening and apparent relaxation time λ of the shear-thickened phase has been investigated systematically for dilute Cetyl-trimethylammonium bromide/sodium salicylate solutions. Experimental data suggest a self-similar behavior of γc and λ as functions of Cs. Specifically, γc∼Cs−6 whereas λ∼Cs6 such that an effective Weissenberg number We≡λγ for the shear-thickened phase is only weakly dependent on Cs. A procedure has been developed to collapse the apparent shear viscosity versus shear rate data obtained for various values of Cs into a single master curve. The effect of Cs on the elastic modulus and mesh size of the shear-induced gel phase for different surfactant concentrations is discussed. Experiments performed using different flow cells (Couette and cone-and-plate) show that γc, λ and the maximum viscosity attained are geometry independent. The elastic modulus of the gel phase inferred indirectly b...
A COMPARISON OF SHORTENING OF THE PROJECTION TO AXIAL ELASTICITY

In this paper we consider the combined bending and axial vibration of beams and we analyze the magnitudes of the different effects that contribute to the motion. Specifically, we consider the transverse elasticity, the axial elasticity, and the shortening of the projection. The goal of our study is to ascertain the circumstances under which the axial elasticity is larger than the shortening of the projection and vice versa. We show that for the majority of cases the shortening of the projection has larger amplitude than the axial stretch. We also develop a general closed-form solution for the response when a force is applied at a free end.
Theoretical high-pressure equations of state and phase diagrams of the alkali metals

Abstract A two-parameter Heine-Abarenkov local pseudopotential has been fitted to experimental solid isotherms of Li, Na, and K to 100 kbar pressure. A one-component plasma fluid variational theory is then used with the fitted potentials to compute alkali metal liquid isotherms, Hugoniots, and melting curves. Agreement between theory and experiment is good.
Probabilistic Simulation of Multi-Scale Composite Behavior

Abstract A methodology is developed to computationally assess the probabilistic composite behavior at all composite scales (from micro to structural) due to the uncertainties in the constituent (fiber and matrix) properties, in the fabrication process and in structural variables (primitive variables). The methodology is computationally efficient for simulating the probability distributions of composite behavior, such as material properties, laminate and structural responses. Byproducts of the methodology are probabilistic sensitivities of the composite primitive variables. The methodology has been implemented into the computer codes: Probabilistic Integrated Composite ANalyzer (PICAN) and Integrated Probabilistic Assessment of Composite Structures (IPACS). The accuracy and efficiency of this methodology are demonstrated by simulating the uncertainties in composite typical laminates and comparing the results with the Monte Carlo simulation method. Available experimental data of composite laminate behavior at all scales fall within the scatters predicted by PICAN. Multi-scaling is extended to simulate probabilistic thermo-mechanical fatigue and to simulate the probabilistic design of a composite redome in order to illustrate its versatility. Results show that probabilistic fatigue can be simulated for different temperature amplitudes and for different cyclic stress magnitudes. Results also show that laminate configurations can be selected to increase the redome reliability by several orders of magnitude without increasing the laminate thickness––a unique feature of structural composites.
On Symplectic Cobordisms

In this note we make several observations concerning symplectic cobordisms. Among other things we show that every contact 3-manifold has infinitely many concave symplectic fillings and that all overtwisted contact 3-manifolds are “symplectic cobordism equivalent”.
Why Quantum Mechanics is Complex

The zero-signature Killing metric of a new, real-valued, 8-dimensional gauging of the conformal group accounts for the complex character of quantum mechanics. The new gauge theory gives manifolds which generalize curved, relativistic phase space. The difference in signature between the usual momentum space metric and the Killing metric of the new geometry gives rise to an imaginary proportionality constant connecting the momentumlike variables of the two spaces. Path integral quantization becomes an average over dilation factors, with the integral of the Weyl vector taking the role of the action. Minimal U(1) electromagnetic coupling is predicted.
Efficient pseudorandom functions from the decisional linear assumption and weaker variants

In this paper, we generalize Naor and Reingold's construction of pseudorandom functions under the DDH Assumption [22] to yield a construction of pseudorandom functions under the decisional k-Linear Assumption, for each k › 1. The decisional Linear Assumption was first introduced by Boneh, Boyen, and Shacham in [5] as an alternative assumption for settings where the DDH problem is easy, such as bilinear groups. Shacham [25] and Hofheinz and Kiltz [16] independently introduced the generalized decisional k-Linear Assumptions and showed that the decisional (k+1)-Linear problem is hard for generic groups even when the decisional k-Linear problem is easy. It is thus desirable to have constructions of cryptographic primitives based on the decisional k-Linear Assumption instead of DDH. Not surprisingly, one must pay a small price for added security: as k increases, our constructed functions become slightly less efficient to compute and the key size increases (quadratically in k).
The relationship between geophysical conditions and ELF amplitude in modulated heating experiments at HAARP: Modeling and experimental results

Extremely Low Frequency (ELF) wave generation using the ionospheric heater at the High Frequency Active Auroral Research Program facility in Gakona, Alaska depends on electrojet currents. We use diagnostics from a radar, riometer, ionosonde, and magnetometer chain to understand how natural conditions affect ELF generation. We then present results of statistical models that show ELF amplitude is proportional to magnetometer measurements for a fixed value of riometer absorption, and that the proportionality constant decreases as riometer absorption increases. Numerical simulations using several ionospheric density profiles verify that denser profiles result in smaller gains for ELF generation than for electrojet current.
Inverse Littlewood-Offord theorems and the condition number of random discrete matrices

Consider a random sum r)\V\ + • • • + r]nvn, where 771, . . . , rin are independently and identically distributed (i.i.d.) random signs and vi, . . . , vn are integers. The Littlewood-Offord problem asks to maximize concentration probabilities such as P(r?i^iH In this paper we develop an inverse Littlewood-Offord theory (somewhat in the spirit of Freiman's inverse theory in additive combinatorics), which starts with the hypothesis that a concentration probability is large, and concludes that almost all of the v\ , . . . , vn are efficiently contained in a generalized arithmetic progression. As an application we give a new bound on the magnitude of the
Current collection by a long conducting cylinder in a flowing magnetized plasma

The numerical techniques, the definitions, and the normalizations used in the simulations of plasma flow past a long conducting cylinder with a magnetic field along the cylinder axis are described. The effect of cross-field plasma transport on the current collection without any contribution to the current from the field-aligned motion of the plasma particles is highlighted. The electric fields in the structure create a two-cell circulation of the electrons near the cylinder. The cell in the wake region has negative potentials. A fan-shaped circulation cell forms around the cylinder and in this cell the potential is generally positive. The geometry and the size of this positive cell affect the current collection. The potential structure around the cylinder is examined, along with its effect on the current collection and its oscillatory behavior. The variation of the time-average current as a function of the relative motion between the plasma and the cylinder is also investigated.
Measurable Categories and 2-Groups

Using the theory of measurable categories developed in [10], we provide a notion of representations of 2-groups better suited to physically and geometrically interesting examples than that using 2-VECT (cf. [8]). Using this theory we sketch a 2-categorical approach to the state-sum model for Lorentzian quantum gravity proposed in [6], and suggest state-integral constructions for 4-manifold invariants.
On the Price of Heterogeneity in Parallel Systems

Suppose we have a parallel or distributed system whose nodes have limited capacities, such as processing speed, bandwidth, memory, or disk space. How does the performance of the system depend on the amount of heterogeneity of its capacity distribution? We propose a general framework to quantify the worst-case effect of increasing heterogeneity in models of parallel systems. Given a cost function g(C,W) representing the system’s performance as a function of its nodes’ capacities C and workload W (such as the makespan of an optimum schedule of jobs W on machines C), we say that g has price of heterogeneity α when for any workload, cost cannot increase by more than a factor α if node capacities become arbitrarily more heterogeneous. The price of heterogeneity also upper bounds the “value of parallelism”: the maximum benefit obtained by increasing parallelism at the expense of decreasing processor speed. We give constant or logarithmic bounds on the price of heterogeneity of several well-known job scheduling and graph degree/diameter problems, indicating that in many cases, increasing heterogeneity can never be much of a disadvantage.
Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending, Part 2: Statistical Tube Tolerance Analysis and Adaptive Bend Correction

The control of each individual bend and overall process is presented in Part 1 of the paper. In Part 2 of the paper, statistical methods are used to analyze and improve 3-D tube bending accuracy. The relationship between bending process error and tube geometry error is obtained with Monte Carlo simulation. For the same tube tolerance requirement, the required process tolerance varies in a large range based on tube geometry. Among the three bending errors: bend angle, bend plane and distance between bends, bend angle error has the largest influence on tube error. For a tube with multiple bends, the overall tube geometry error can be minimized by intentionally modifying the nominal values of the bends to be made based on the errors in the existing bends. The required modification of the bending commands is calculated with an adaptive bend correction algorithm.
Speed estimation in wireless systems using wavelets

A new technique is described for estimating the speed of a mobile station in a wireless system. The mobile speed maps the characteristic spatial scale of the received signal into a characteristic temporal scale. The continuous wavelet transform tracks changes in the temporal scale to estimate the mobile speed as a function of time. This technique requires neither knowledge of the average received power of the nonstationary signal nor adaptation of a temporal observation window, in contrast to other speed estimators given in the literature. Simulations show the tracking of a variable speed profile.
Upscaling relative permeabilities in a structured porous medium

Upscaling of multi-phase flow problems for a heterogeneous porous medium requires modification of constitutive functions at the grid-block scale. A particular type of heterogeneity that has important environmental consequences involves thin, continuous streaks of high permeability through lower-permeability background rocks. These streaks, which may correspond to features like abandoned wells in mature sedimentary basins, can become preferential flow paths for an invading fluid. Quantification of flow through these types of heterogeneities in deep, geological formations is necessary for estimates of migration and possible leakage of injected fluids such as hazardous liquid wastes, municipal liquid wastes, and, possibly, carbon dioxide. One of the important constitutive functions for proper estimation of flow through these flow paths is the relative permeability function. In the simple case of a single high-permeability streak in a uniform rock matrix, with both materials having identical (local) relative permeability functions, the upscaled relative permeability must be changed significantly to capture the proper leakage. Standard petroleum reservoir pseudo-functions for relative permeability capture the general features of the upscaled function, but they still produce errors of several hundred percent in the leakage estimation. Detailed three-dimensional numerical simulations and associated upscaled calculations demonstrate the proper form for the upscaled relative permeability, and provide a modified derivation of pseudo-functions to capture the leakage behavior in upscaled models.
Oxidative Rearrangement of Yohimbanones

Abstract A concise new route to 1‐aroyl‐β‐carboline‐3‐carboxylates is presented in the context of a novel oxidative ring opening of the yohimbanone backbone.
The intensifying effects of exciting television programs on the reception of subsequent commercials

This paper examines the effects of viewer excitement as elicited by television programs on the effectiveness of commercials embedded in such programs. A review of the literature suggests that the physiological arousal which results from suspenseful or emotional programs can be usefully characterized as an intensifier of important viewer responses. A brief overview of the literature on program context effects to date is given and a model is developed which positions arousal in relation to other mediating variables affecting commercial impact. The paper concludes with a summary of the more pressing issues arising from the study of excitement as an aspect of media environment.
4D-QSAR analysis of a set of ecdysteroids and a comparison to CoMFA modeling.

The ecdysteroid-responsive Drosophila melanogaster BII cell line is a prototypical homologous inducible gene expression system. A training set of 71 ecdysteroids, for which the −log(EC50) potencies in the ecdysteroid-responsive BII cell line were measured, was used to construct 4D-QSAR models. Four nearly equivalent optimum 4D-QSAR models, for two modestly different alignments, were identified (Q2 = 0.76−0.80). These four models, together with two CoMFA models, were used in consensus modeling to arrive at a three-dimensional pharmacophore. The C-2 and C-22 hydroxyls are identified as hydrogen-bond acceptor sites which enhance activity. A hydrophobic site near C-12 is consistent with increasing activity. The side-chain substituents at C-17 are predicted to adopt semiextended “active” conformations which could fit into a cylinder-shaped binding pocket lined largely with nonpolar residues for enhanced activity. A test set of 20 ecdysteroids was used to evaluate the QSAR models. Two 4D-QSAR models for one ali...
Cooperating or fighting with control noise in the optimal manipulation of quantum dynamics

This paper investigates the impact of control field noise on the optimal manipulation of quantum dynamics. Simulations are performed on several multilevel quantum systems with the goal of population transfer in the presence of significant control noise. The noise enters as run-to-run variations in the control amplitude and phase with the observation being an ensemble average over many runs as is commonly done in the laboratory. A genetic algorithm with an improved elitism operator is used to find the optimal field that either fights against or cooperates with control field noise. When seeking a high control yield it is possible to find fields that successfully fight with the noise while attaining good quality stable results. When seeking modest control yields, fields can be found which are optimally shaped to cooperate with the noise and thereby drive the dynamics more efficiently. In general, noise reduces the coherence of the dynamics, but the results indicate that population transfer objectives can be met by appropriately either fighting or cooperating with noise, even when it is intense.
Attractive energy and entropy or particle size: the Yin and Yang of physical and biological science

It is well known that equilibrium in a thermodynamic system results from a competition or balance between lowering the energy and increasing the entropy, or at least the product of the temperature and entropy. This is remarkably similar to the Taoist concept of yin, a downward influence, and yang, an upward influence, where harmony is established by balancing yin and yang. Entropy is due to structure, which is largely determined by core repulsions or particle size whereas energy is largely determined by longer range attractive interactions. Here, this balance between energy and entropy or particle size is traced through the theory of simple fluids, begining with Andrews and van der Waals, the subsequent developments of perturbation theory, theories of correlation functions that are based on the Ornstein-Zernike relation and the mean spherical approximation, electrolytes, and recent work on ion channels in biological membranes, where the competition between energy and size gives an intuitively attractive explanation of the selectivity of cation channels. Simulations of complex systems, including proteins in aqueous solution, should be studied to determine the extent to which these concepts are useful for such situations.
Active tuning and coupling enhancement of piezoelectric vibration absorbers for variable-frequency harmonic excitations in multiple-degrees-of-freedom mechanical systems

It has been shown that piezoelectric materials can be used as electromechanical vibration absorbers when they are shunted by an electrical network. Semi-active piezoelectric absorbers have also been proposed for the purpose of suppressing harmonic excitations with varying frequencies. These semi- active devices can be constructed using a variable inductance or variable capacitance element in the shunt circuit, however both of these implementations have several limitations that restrict their practical use. The design presented here is a high performance alternative to semi-active absorbers that uses a combination of a passive RL circuit and an adaptive feedback law to suppress harmonic excitations with varying frequency. The adaptive tuning is accomplished by simulating a variable inductor using feedback. An equation for the optimal tuning of the piezoelectric absorber on a general MDOF structure is derived. Next, it is illustrated that the performance and robustness of the piezoelectric absorber can be increased by using additional active actions to reduce the circuit resistance and enhance the coupling of the piezoelectric. Two methods for increasing the effective coupling of the absorber are examined -- a negative capacitance shunt and active coupling feedback. Finally, the effectiveness of the proposed algorithm is demonstrated experimentally.
Risk sharing vs. incentives: Contract design under two-sided heterogeneity

We study the matching patterns between heterogeneous principals and agents in a principal agent model. The resulting equilibrium relationship between risk and incentives could be negative, positive or U-shaped. These results may provide an explanation for the absence of systematic empirical support for the standard risk model. D 2005 Elsevier B.V. All rights reserved.
Development of a Design Model for Airfoil Leading Edge Film Cooling

Leading edge showerhead cooling designs represent an important feature of certain classes of high temperature turbine airfoils. This paper outlines a methodology for predicting the surface temperatures of showerhead designs with spanwise injection through an array of discrete holes. The paper describes a series of experiments and analyses on scaled cylinder models with injection through holes inclined at 20, 30, 45, and 90 degrees for typical radial and circumferential spacing-to-diameter ratios of 10 and 4, respectively. The experiments were conducted in a wind tunnel on several stainless steel test specimens in which flow and heat transfer parameters were measured over the simulated airfoil leading edge surfaces. Based on the experiments, an engineering design model is proposed that treats the gas-to-surface heat transfer coefficient with film cooling in a manner suggested by a recent Purdue-NASA investigation and includes the important contribution of upstream (coolant inlet face) heat transfer. The experiments suggest that the averaged film cooling effectiveness in the showerhead region is primarily influenced by the inclination of the injection holes. The effectiveness parameter is not strongly affected by variations in coolant-to-gas stream pressure ratio, freestream Mach number, gas-to-coolant temperature ratio and gas stream Reynolds number. This is appropriately reflected in the design model in which the increase in coolant side heat transfer coefficient (with blowing ratio) is essentially offset by a simultaneous increase in the gas side film coefficient. The model is also employed to determine (inferentially) the average Stanton number reduction parameter for a series of pressure ratios varying from 1.004 to 1.3, Mach numbers ranging from 0.1 to 0.2, temperature ratios between 1.6 and 2.0, and Reynolds numbers ranging from 3.5 × 104 to 9.0 × 104. Design capabilities of the analytical model are explored for typical high temperature first stage turbine vanes and rotor blades operating at rotor inlet temperatures in excess of 1644°K.© 1985 ASME
Estimating Central Bank Preferences under Commitment and Discretion

This paper explains U.S. macroeconomic outcomes with an empirical New Keynesian model in which monetary policy minimizes the central bank’s loss function. The presence of expectations in the model forms a well-known distinction between two modes of optimization, termed commitment and discretion. The model is estimated separately under each policy using maximum likelihood over the Volcker–Greenspan–Bernanke period. Comparisons of fit reveal that the data favor the specification with discretionary policy. Estimates of the loss function weights point to an excessive concern for interest rate smoothing in the commitment model but a more balanced concern relative to inflation and output stability in the discretionary model.
Level Curve Configurations and Conformal Equivalence of Meromorphic Functions

Let $$f=B_1/B_2$$ be a ratio of finite Blaschke products having no critical points on $$\partial \mathbb {D}$$ . Then $$f$$ has finitely many critical level curves (level curves containing critical points of $$f$$ ) in the disk, and the non-critical level curves interpolate smoothly between the critical level curves. Thus, to understand the geometry of all the level curves of $$f$$ , one needs only understand the configuration of the finitely many critical level curves of $$f$$ . In this paper, we show that in fact such a function $$f$$ is determined not just geometrically but conformally by the configuration of its critical level curves. That is, if $$f_1$$ and $$f_2$$ have the same configuration of critical level curves, then there is a conformal map $$\phi $$ such that $$f_1\equiv f_2\circ \phi $$ . We then use this to show that every configuration of critical level curves which could come from an analytic function is instantiated by a polynomial. We also include a new proof of a theorem of Bocher (which is an extension of the Gauss–Lucas theorem to rational functions) using level curves.
A Constrained-Transport Magnetohydrodynamics Algorithm with Near-Spectral Resolution

Numerical simulations including magnetic fields have become important in many fields of astrophysics. Evolution of magnetic fields by the constrained-transport algorithm preserves magnetic divergence to machine precision and thus represents one preferred method for the inclusion of magnetic fields in simulations. We show that constrained transport can be implemented with volume-centered fields and hyperresistivity on a high-order finite-difference stencil. In addition, the finite-difference coefficients can be tuned to enhance high-wavenumber resolution. Similar techniques can be used for the interpolations required for dealiasing corrections at high wavenumber. Together, these measures yield an algorithm with a wavenumber resolution that approaches the theoretical maximum achieved by spectral algorithms. Because this algorithm uses finite differences instead of fast Fourier transforms, it runs faster and is not restricted to periodic boundary conditions. In addition, since the finite differences are spatially local, this algorithm is easily scalable to thousands of processors. We demonstrate that, for low-Mach number turbulence, the results agree well with a high-order, non-constrained-transport scheme with Poisson divergence cleaning.
Molecular mechanics (MM2 and MM3) calculations on aliphatic and aromatic nitro compounds

Abstract The structures of a variety of nitroalkanes, and nitrocyclopropane, nitroethylene, and nitrobenzene have been studied using molecular mechanics methods. Heats of formation fit well and the vibrational spectra moderately well.
Polyethylene Glycol Without Electrolytes for Children With Constipation and Encopresis

ABSTRACTBackgroundChildren with functional constipation and encopresis benefit from behavior modification and from long-term laxative medication. Polyethylene glycol without electrolytes has become the first option for many pediatric gastroenterologists.MethodsTwenty-eight children treated with poly
Microphysics of Shock Acceleration from Observations of X-Ray Synchrotron Emission from Supernova Remnants

Recent observations of non-thermal X-rays from supernova remnants have been attributed to synchrotron radiation from the loss-steepened tail of a non-thermal distribution of electrons accelerated at the remnant blast wave. In the test-particle limit of diffusive shock acceleration, in which the energy in shock-accelerated particles is unimportant, the slope of a shock-accelerated power-law is independent of the diffusion coefficient κ and on how κ depends on particle energy. However, the maximum energy to which particles can be accelerated depends on the rate of acceleration and that does depend on the energy-dependence of the diffusion coefficient. If the time to accelerate an electron from thermal energies to energy E≫mec2 is τ(E) and if κ∝Eβ, then τ(E)∝Eβ in parallel shocks and τ∝E2−β in perpendicular shocks. Most work on shock acceleration has made the plausible assumption that κ∝rg (where rg is the particle gyroradius), so that β=1 at relativistic energies, implying a particular (wavelength-independent) spectrum of MHD turbulence, where Kolmogorov or Kraichnan spectra might be more physically plausible. I derive the β dependence of the maximum electron energy resulting from limitations due to radiative (synchrotron and inverse-Compton) losses and to finite remnant age (or size). I then exhibit calculations of synchrotron X-ray spectra, and model images, for supernova remnants as a function of β and compare to earlier β=1 results. Spectra can be considerably altered for β<1 and images are dramatically different for values of β corresponding to Kolmogorov or Kraichnan spectra of turbulence. The predicted images are quite unlike observed remnants, suggesting that the turbulence near SNRs is generated by the high-energy particles themselves.
Stereospecific intramolecular C-H amination of 1-aza-2-azoniaallene salts.

We report that 1-aza-2-azoniaallene salts, generated from α-chloroazo compounds by treatment with halophilic Lewis acids, participate in intramolecular C–H amination reactions to provide pyrazoline products in good to excellent yield. This intramolecular amination occurs readily at both benzylic and tertiary aliphatic positions and proceeds at an enantioenriched chiral center without loss of enantiomeric excess. A competition reaction shows that insertion occurs more readily at an electron-rich benzylic position than an electron-deficient one. These observations are consistent with the 1-aza-2-azoniaallene intermediate reacting as a nitrenium-like ion by a concerted insertion mechanism.
The Ventral Striatum of the Syrian Hamster

The Syrian hamster, Mesocricetus auratus, was first used in laboratory experiments some fifty years ago in the Middle East, from animals captured in the wild. 1 Since then the Syrian hamster has been domesticated and used extensively in laboratory studies of motivation, includuing reproduction, feeding, aggression and circadian behaviors. 2 In comparison to the rat, the male Syrian hamster is a solitary animal known for its territorial aggression, photoperiodic mating and hoarding behaviors. Many neural circuits controlling reproductive behaviors are now known. 3 While these motivated behaviors have been demonstrated to be regulated by endocrine status there is increasing evidence that dopamine within the nucleus accumbens conveys the rewarding tone of sexual motivation
Macrocyclic Drugs and Synthetic Methodologies toward Macrocycles

Macrocyclic scaffolds are commonly found in bioactive natural products and pharmaceutical molecules. So far, a large number of macrocyclic natural products have been isolated and synthesized. The construction of macrocycles is generally considered as a crucial and challenging step in the synthesis of macrocyclic natural products. Over the last several decades, numerous efforts have been undertaken toward the synthesis of complex naturally occurring macrocycles and great progresses have been made to advance the field of total synthesis. The commonly used synthetic methodologies toward macrocyclization include macrolactonization, macrolactamization, transition metal-catalyzed cross coupling, ring-closing metathesis, and click reaction, among others. Selected recent examples of macrocyclic synthesis of natural products and druglike macrocycles with significant biological relevance are highlighted in each class. The primary goal of this review is to summarize currently used macrocyclic drugs, highlight the therapeutic potential of this underexplored drug class and outline the general synthetic methodologies for the synthesis of macrocycles.
An experimental study of a pulse compression scatterometer system

The ideal scatterometer, operating from either an aircraft or a satellite platform, should be capable of making rapid, accurate estimates of the sea backscatter cross section \sigma over as wide a range of grazing angles \psi as possible. Efficient operation over a large range of grazing angles is desirable because 1) \sigma behavior for 90\deg \geq \psi \geq 70\deg yields rms gravity wave slope information and is an indicator of sea state and 2) \sigma behavior for 70\deg \geq \psi \geq 0\deg yields data on surface wind magnitude and direction as well as information about the power spectrum of the sea. A "hybrid" estimation procedure has been developed for pulse compression radars which uses both frequency and spatially decorrelated samples of \sigma to provide an unbiased estimate of \sigma having minimum variance over the entire range of grazing angles for which radar reception is not noise-limited.
A facile synthesis of 5-alkoxypyrrol-2(5H)-ones using a modified aza-Achmatowicz oxidation

An efficient approach to 2,4-disubstituted pyrroles has been uncovered and is based on an oxidative rearrangement of a furanyl carbamate followed by sequential reaction of the resulting 5-methoxypyrrol-2(5H)-one with various alkyl lithiates. The final step of the procedure involves heating the ring opened 1-methoxy-5-oxopentylcarbamate with a primary amine. The overall process can be carried out under mild conditions and complements existing methods to prepare 2,4-disubstituted pyrroles.
320 x 256 complementary barrier infrared detector focal plane array for long-wave infrared imaging

A 320 x 256 Complementary Barrier Infrared (CBIRD) focal plane array for long-wavelength infrared (LWIR) imaging is reported. The arrays were grown by molecular beam expitaxy (MBE) with a 300 period 1.9 um thick absorber. The mean dark current density of 2.2 x 10-4 A/cm2 was measured at an operating bias of 128 mV with a long wavelength cutoff of 8.8 mm observed at 50% of the peak. The maximum quantum efficiency was 54% measured at 5.6 mm. Operating at T = 80K, the array yielded an 81% fill factor with 97% operability. Good imagery with a mean noise equivalent different temperature (NEuT) of 18.6 mK and a mean detectivity of D* = 1.3 x 1011 cm-Hz1/2/W was achieved. The substrate was thinned using mechanical lapping and neither an AR coating nor a passivation layer was applied. This article provides the details of the fabrication process for achieving low-dark current LWIR CBIRD arrays. Discussion for an effective hard mask for excellent pattern transfer is given and appropriate mounting techniques for good thermal contact during the dry etching process is described. The challenges and differences between etching large 200 mm test diodes and small 28 mm FPA pixels are given.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.