cssi/SciSciGPT-SciSciNet huggingface dataset:
Excess Modes and Enhanced Scattering in Rare-Earth Doped Amorphous Silicon Thin Films

We report specific heat and thermal conductivity of gadolinium- and yttrium-doped amorphous silicon thin films measured using silicon-nitride membrane-based microcalorimeters. Addition of gadolinium or yttrium to the amorphous silicon network reduces the thermal conductivity over a wide temperature range while significantly increasing the specific heat. This result indicates that a large number of nonpropagating states are added to the vibrational spectrum that are most likely caused either by localized vibration of the dopant atom in a Si cage or softening of the material forming the cage structures. High-resolution cross-sectional electron micrographs reveal columnar features in Gd-doped material which do not appear in pure amorphous silicon. Scattering from both the nanoscaled columns and the filled-cage structures play a role in the reduced thermal conductivity in the rare-earth-doped amorphous semiconductor. The overall result is an amorphous solid with a large bump in $C∕{T}^{3}$ and no plateau in thermal conductivity.
Interaction of Astrodynamics and a Mars Imaging Mission

Arrival geometry at the planet and orbit size significantly influence sensor field-of-view requirements, mapping altitude, and subvehicle illumination. Additional consideration of mapping time, planet coverage, allowable velocity, and data transmission capability result in a complex interaction of these parameters. The 1973 opportunity is taken for illustration, and the use of Type I trajectories is assumed. The present paper graphically displays these interactions with emphasis on the imaging experiment and telecommunication subsystem. Polar and inclined orbits are examined, and the effects of apsidal rotation and orbit inclination on illumination are discussed. Design charts that allow a rapid preliminary determination of sensor field-of-view and velocity requirements are presented. Auxiliary design charts determine the related bit rate and storage requirements, assuming a contiguous mapping mode. The data transmission capability of the telecommunication subsystem is expressed in terms of antenna si^e, power gain product, and subsystem weight.
Facile One-Pot Conversion of Aldehydes into Amides

A facile one-pot synthesis of amides from aldehydes has been developed. This tandem process involves the formation of a nitrile intermediate obtained from the reaction of an aldehyde with hydroxylamine hydrochloride in dimethylsulfoxide at 100°C and the subsequent treatment of the nitrile with basic hydrogen peroxide. The resulting amide products were produced in good yields (67–95%) and purity (>95%).
Possible effects of European Monetary Union on Switzerland

Abstract This paper examines the possible effects on Switzerland of asset preference shifts in favor of Swiss franc-denominated assets that could result from European Economic and Monetary Union (EMU). Alternative policy responses to temporary and persistent asset preference shifts and the consequent pressures for exchange rate appreciation are examined. Simulations of a stylized macroeconomic model of the Swiss economy indicate that monetary policy is likely to be the most effective tool for stabilizing output in the short run, but at the cost of a temporary increase in inflationary pressures. The simulations highlight the dilemmas faced by policymakers in an environment with low levels of inflation and nominal interest rates.
Peptidic macrocyclization via palladium-catalyzed chemoselective indole C-2 arylation.

A highly efficient macrocyclization reaction has been developed via the palladium-catalyzed C–H arylation of the side-chains of tryptophan with halophenyl-containing amino acids. This method allows for direct access to 15- to 25-membered biaryl macrocycles in 40–75% yield, at moderate concentration, with C–H arylation proceeding exclusively at the C-2 position of the tryptophan indole.
GeV emission from the nearby radio galaxy Centaurus A

Abstract EGRET has detected 67 sources associated with active galactic nuclei. With the exception of radio galaxy Cen A, all are classified as belonging to the blazar class of active galactic nuclei. The cumulative exposure from multiple EGRET observations has provided the first clear detection of Centaurus A. Unlike the γ-ray blazars seen by EGRET which are believed to exhibit near-alignment of the central jet along the line-of-sight, Cen A provides the first evidence for > 100 MeV emission from a source with a confirmed large-inclination jet. Although the high-energy emission represents a lower luminosity than most EGRET blazars, with the advent of new more sensitive instruments such as GLAST and VERITAS, the detection of off-axis high-energy emission from more distant radio galaxies (space density of radio galaxies being ∼103 times the blazar density) is an exciting possibility.
Effect of tapering on optical guiding and sideband growth in a finite-pulse free-electron laser

Abstract The radiation outputs from a finite-pulse high-power laser for several tapering rates are compared. Simulations reveal that fast tapering leads to increased efficiency as compared to slow tapering, but with little change in the peak radiation intensity. Increasing the tapering rate reduces refractive guiding and increases the spot size of the optical field. The enhanced power for fast tapering rates is due to the increase in the optical pulse cross section, rather than an increase in the amplitude. This is analyzed by an envelope equation for the radiation beam. Reduced sideband modulation due to distortion of the synchrotron motion by the tapering is also observed.
Preparation of Trifluoromethylated Dihydrocoumarins, Indanones, and Arylpropanoic Acids by Tandem Superacidic Activation of 2-(Trifluoromethyl)acrylic Acid with Arenes

Indanones and coumarins are important intermediates for the convenient synthesis of many pharmaceutical and biologically active compounds. Fluoroorganics play a vital role in the design of very effective therapeutics due to significant enhancenment in their lipophilicity, bioavailability, and fast uptake by the presence of fluorine in these molecules. Herein, we report an efficient one-pot synthesis of trifluoromethylated arylpropanoic acids, indanones, and dihydrocoumarins using Friedel−Crafts alkylation or tandem Friedel−Crafts alkylation−cycloacylation of arenes/phenols with 2-(trifluoromethyl)acrylic acid under superacidic conditions using trifluoromethanesulfonic acid. The results have been rationalized by the structure energy calculations of the involved reaction intermediates using ab initio theoretical methods.
ANALYSIS OF SPITZER SPECTRA OF IRRADIATED PLANETS: EVIDENCE FOR WATER VAPOR?

Published mid-infrared spectra of transiting planets HD 209458b and HD 189733b, obtained during secondary eclipse by the InfraRed Spectrograph (IRS) aboard the Spitzer Space Telescope, are predominantly featureless. In particular, these flux ratio spectra do not exhibit an expected feature arising from water vapor absorption shortward of . Here we suggest that in the absence of flux variability, the spectral data for HD 189733b 10 mm are inconsistent with 8 mm photometry obtained with Spitzer’s InfraRed Array Camera (IRAC), perhaps an indication of problems with the challenging reduction of the IRS spectra. The IRAC point, along with previously published secondary eclipse photometry for HD 189733b, are in good agreement with a one-dimensional model of HD 189733b that clearly shows absorption due to water vapor in the emergent spectrum. We are not able to draw firm conclusions regarding the IRS data for HD 209458b, but spectra predicted by 1D and 3D atmosphere models fit the data adequately, without adjustment of the water abundance or reliance on cloud opacity. We argue that the generally good agreement between model spectra and IRS spectra of brown dwarfs with atmospheric temperatures similar to these highly irradiated planets lends confidence in the modeling procedure. Subject headings: planetary systems — radiative transfer — stars: individual (HD 189733, HD 209458)
Synthesis of New Dideoxynucleosides Bearing Ring-Extended Nucleobases

Abstract New dideoxynucleosides where the nucleobase is lin-benzoadenine is reported. The key target compound, (S,S)-isodideoxybenzoadenosine, is stable with respect to hydrolytic cleavage of the glycosyl bond and it is a poor substrate for adenosine deaminase. Its monophosphate is not a substrate for AMP deaminase.
Vaporization thermodynamics and heat capacities of Cr3Ge and Cr5Ge3

Abstract Thermodynamic stabilities of two chromium germanides Cr 3 Ge and Cr 5 Ge 3 have been studied by means of high-temperature Knudsen effusion mass spectrometry (KEMS) and differential scanning calorimetry (DSC). Thermodynamic activities of Cr and Ge have been measured over the Cr 3 Ge single phase and over two-phase mixtures of (Cr) solid solution+Cr 3 Ge and Cr 3 Ge+Cr 5 Ge 3 in a temperature range of approximately 1400–1600 K by direct comparison with solid Cr and liquid Ge metals. The standard free energies of formation of the chromium germanides at high temperature were determined from the activity data. Heat capacities of Cr 0.75 Ge 0.25 and Cr 0.63 Ge 0.37 were measured by DSC in the temperature range of 300–700 K. Standard enthalpies of formation of Cr 0.75 Ge 0.25 and Cr 0.63 Ge 0.37 at 298 K were calculated by the third-law method with the use of literature absolute entropy and estimated high-temperature heat capacity data. The results obtained are: Cr 0.75 Ge 0.25 , −19.3±2.5 kJ; Cr 0.63 Ge 0.37 , −12.3±2.5 kJ. The results are compared with previously reported measurements.
A combinatorial proof of the Rogers-Ramanujan and Schur identities

We give a combinatorial proof of the first Rogers-Ramanujan identity by using two symmetries of a new generalization of Dyson's rank. These symmetries are established by direct bijections.
Maximum-Rate Transmission With Improved Diversity Gain for Interference Networks

Interference alignment (IA) was shown to be effective for interference management in improving transmission rate in terms of the degree of freedom (DoF) gain. On the other hand, orthogonal space-time block codes were widely used in point-to-point multiantenna channels to enhance transmission reliability in terms of the diversity gain. In this paper, we connect these two ideas, i.e., IA and space-time block coding, to improve the designs of alignment precoders for multiuser networks. Specifically, we consider the use of Alamouti codes for IA because of their rate-one transmission and achievability of full diversity in point-to-point systems. The Alamouti codes protect the desired link by introducing orthogonality between the two symbols in one Alamouti codeword, and create alignment at the interfering receiver. We show that the proposed alignment methods can maintain the maximum DoF gain and improve the ergodic mutual information in the long-term regime, while increasing the diversity gain to 2 in the short-term regime. The presented examples of interference networks have two antennas at each node and include the two-user X channel, the interfering multiaccess channel, and the interfering broadcast channel.
A ``littlest Higgs'' model with custodial SU(2) symmetry

In this note, a ``littlest higgs'' model is presented which has an approximate custodial SU(2) symmetry. The model is based on the coset space SO(9)/(SO(5) × SO(4)). The light pseudo-goldstone bosons of the theory include a single higgs doublet below a TeV and a set of three SU(2)W triplets and an electroweak singlet in the TeV range. All of these scalars obtain approximately custodial SU(2) preserving vacuum expectation values. This model addresses a defect in the earlier SO(5) × SU(2) × U(1) moose model, with the only extra complication being an extended top sector. Some of the precision electroweak observables are computed and do not deviate appreciably from Standard Model predictions. In an S-T oblique analysis, the dominant non-Standard Model contributions are the extended top sector and higgs doublet contributions. In conclusion, a wide range of higgs masses is allowed in a large region of parameter space consistent with naturalness, where large higgs masses requires some mild custodial SU(2) violation from the extended top sector.
TERAHERTZ GaAs DEVICES AND CIRCUITS FOR HETERODYNE RECEIVER APPLICATIONS

GaAs Schottky barrier diodes are used in heterodyne receiver applications to frequencies as high as 4,000 GHz. The primary application that has driven this technology has been radio astronomy. However, other applications are now also very important, particularly studies of the constituents of the Earth’s atmosphere. This paper presents a summary of this increasingly important technology. The requirements that the diodes must meet and the benefits of GaAs Schottky devices are discussed. The optimization of the diodes for frequency mixing and multiplication throughout the frequency range of interest is overviewed. The analysis of terahertz frequency electronic transport in the diodes is then briefly considered with an emphasis on numerical modeling techniques. The typical circuit designs and the efficient coupling of energy are considered, and the state-of-the-art systems are reviewed. Finally, ongoing and future research topics are discussed. It is concluded that although this technology is quite well developed, much remains to be done, particularly in the areas of combining accurate circuit and device simulations for optimization and design purposes and the development of lower cost systems.
Low Noise Preamplifiers/Amplifiers for the Time Projection Chamber

The special problems associated with the Time Projection Chamber resulted in the development of a new preamplifier/amplifier system which is discussed here. The need for 16,000 channels of low noise electronics imposed serious constraints on the cost, size, and power consumption of the Circuits. Also the preamplifiers are designed to work inside the detector chamber. This chamber operates at 10 atmosphere pressure and is sensitive both to the presence of magnetic materials that distort the drift field, and to the effects of gas contamination. These problems resulted in the use of new components and fabrication techniques as described in the paper. The large number of units involved requires automatic testing as discussed in the paper.
Semistability theory for spatially distributed systems

Abstract The concepts of semistability and exponential semistability are well-developed for finite-dimensional systems with nonisolated equilibrium points, where asymptotic or exponential stability is not possible. Definitions of semistability and exponential semistability have recently been formulated for networks with time-delays. This paper further extends the semistability theory to continuous and discrete spatially distributed systems. This requires the definition of the notions of exact and approximate semicontrollability and semiobservability, and discrete approximate semicontrollability and semiobservability. Also introduced is the property of weak semistability. Necessary and sufficient conditions are given for exponential semistability and weak semistability, and sufficient conditions are given for semistability.
Transport of diazinon in the San Joaquin River Basin, California

ABSTRACT: Most of the application of the organophosphate insecticide diazinon in the San Joaquin River Basin occurs in winter to control wood-boring insects in dormant almond orchards. A federalstate collaborative study found that diazinon accounted for most of the observed toxicity of San Joaquin River water in February 1993. Previous studies focused mainly on west-side inputs to the San Joaquin River. In this 1994 study, the three major east-side tributaries to the San Joaquin River - the Merced, Tuolumne, and Stanislaus rivers - and a downstream site on the San Joaquin River were sampled throughout the hydrographs of a late January and an early February storm. In both storms, the Tuolumne River had the highest concentrations of diazinon and transported the largest load of the three tributaries. The Stanislaus River was a small source in both storms. On the basis of previous storm sampling and estimated travel times, ephemeral west-side creeks probably were the main diazinon source early in the storms, whereas the Tuolumne and Merced rivers and east-side drainages directly to the San Joaquin River were the main sources later. Although 74 percent of diazinon transport in the San Joaquin River during 1991–1993 occurred in January and February, transport during each of the two 1994 storms was only 0.05 percent of the amount applied during preceding dry periods. Nevertheless, some of the diazinon concentrations in the San Joaquin River during the January storm exceeded 0.35 μ/L, a concentration shown to be acutely toxic to water fleas. On the basis of this study and previous studies, diazinon concentrations and streamflow are highly variable during January and February storms, and frequent sampling is required to evaluate transport in the San Joaquin River Basin.
Redundant arm kinematic control with recurrent loop

Abstract A new method for generating redundant arm inverse kinematic solutions based on the iterative update of joint vectors is presented. A novel neural network architecture with a recurrent loop is then formed based on the proposed method. In the proposed method, the pseudoinverse of the gradient of a Lyapunov function is defined in the joint space to update the joint vector toward a solution. This differs from the conventional methods based on the Jacobian pseudoinverse or Jacobian transpose. This paper establishes explicit convergence control schemes to achieve fast and stable convergence: 1) the convergence speed is enhanced by modifying the convergence dynamics based on terminal attractors, and 2) the convergence stability is ensured by the adaptive selection of update intervals based on the stability condition derived in this paper. The proposed neural network consists of a feedforward network and a feedback network forming a recurrent loop. The feedforward network is a multilayer network with hidden units having sinusoidal activation functions. As such, it computes accurately the forward kinematic solutions with simple training. The feedback network is derived from the feedforward network and computes joint vector updates. The proposed neural network has definite advantages over conventional neural networks for robot arm kinematic control, because it can not only handle redundant arm kinematic control, but can also provide an accurate computation of forward and inverse kinematic solutions with very simple training. The simulation results demonstrate that the proposed method is effective for the real-time kinematic control of a redundant arm as well as the real-time generation of collision-free joint trajectories.
Experimental Study of Pressure Wave Propagation in Granular Propellant Bed

The ignition transients and penetrative burning characteristics of confined granular propellant beds in a cylindrical tube (loading densities up to 1.03 g cm3 and pressures up to 4000 bar) were investigated to test the 1-D pressure-wave propagation profiles predicted by the 1971 Kuo-Vichnevetsky-Summerfield analytical model. Thus, it was found that following the initial pressure rise along the bed, the position of peak pressure occurs within the bed and progresses downstream at an accelerating rate. The ignition time of the granular bed increases sharply with decreasing loading density. Wall friction acting on the unburned propellant along the tube attenuates downstream transmission of solid phase pressure generated by the upstream burning processes. This work has applications to the internal ballistics of guns, deflagration to detonation transition, and fast-burning rocket charges.
Energetics of cobalt phosphate frameworks: α, β, and red NaCoPO4

Abstract Thermal behavior, relative stability, and enthalpy of formation of α (pink phase), β (blue phase), and red NaCoPO 4 are studied by differential scanning calorimetry, X-ray diffraction, and high-temperature oxide melt drop solution calorimetry. Red NaCoPO 4 with cobalt in trigonal bipyramidal coordination is metastable, irreversibly changing to α NaCoPO 4 at 827 K with an enthalpy of phase transition of −17.4±6.9 kJ mol −1 . α NaCoPO 4 with cobalt in octahedral coordination is the most stable phase at room temperature. It undergoes a reversible phase transition to the β phase (cobalt in tetrahedra) at 1006 K with an enthalpy of phase transition of 17.6±1.3 kJ mol −1 . Enthalpy of formation from oxides of α , β , and red NaCoPO 4 are −349.7±2.3, −332.1±2.5, and −332.3±7.2 kJ mol −1 ; standard enthalpy of formation of α , β , and red NaCoPO 4 are −1547.5±2.7, −1529.9±2.8, and −1530.0±7.3 kJ mol −1 , respectively. The more exothermic enthalpy of formation from oxides of β NaCoPO 4 compared to a structurally related aluminosilicate, NaAlSiO 4 nepheline, results from the stronger acid–base interaction of oxides in β NaCoPO 4 (Na 2 O, CoO, P 2 O 5 ) than in NaAlSiO 4 nepheline (Na 2 O, Al 2 O 3 , SiO 2 ).
Learning a factor model via regularized PCA

We consider the problem of learning a linear factor model. We propose a regularized form of principal component analysis (PCA) and demonstrate through experiments with synthetic and real data the superiority of resulting estimates to those produced by pre-existing factor analysis approaches. We also establish theoretical results that explain how our algorithm corrects the biases induced by conventional approaches. An important feature of our algorithm is that its computational requirements are similar to those of PCA, which enjoys wide use in large part due to its efficiency.
Fractal Structure in Galactic Star Fields

The fractal structure of star formation on large scales in disk galaxies is studied using the size distribution function of stellar aggregates in kiloparsec-scale star fields. Archival Hubble Space Telescope images of 10 galaxies are Gaussian-smoothed to define the aggregates, and a count of these aggregates versus smoothing scale gives the fractal dimension. Fractal and Poisson models confirm the procedure. The fractal dimension of star formation in all of the galaxies is ~2.3. This is the same as the fractal dimension of interstellar gas in the Milky Way and nearby galaxies, suggesting that star formation is a passive tracer of gas structure defined by self-gravity and turbulence. Dense clusters such as the Pleiades form at the bottom of the hierarchy of structures, where the protostellar gas is densest. If most stars form in such clusters, then the fractal arises from the spatial distribution of their positions, giving dispersed star fields from continuous cluster disruption. Dense clusters should have an upper mass limit that increases with pressure, from ~103 M⊙ in regions like the solar neighborhood to ~106 M⊙ in starbursts.
Smooth bumps, a Borel theorem and partitions of smooth functions on p.c.f. fractals

We provide two methods for constructing smooth bump functions and for smoothly cutting off smooth functions on fractals, one using a probabilistic approach and sub-Gaussian estimates for the heat operator, and the other using the analytic theory for p.c.f. fractals and a fixed point argument. The heat semigroup (probabilistic) method is applicable to a more general class of metric measure spaces with Laplacian, including certain infinitely ramified fractals; however the cutoff technique involves some loss in smoothness. From the analytic approach we establish a Borel theorem for p.c.f. fractals, showing that to any prescribed jet at a junction point there is a smooth function with that jet. As a consequence we prove that on p.c.f. fractals smooth functions may be cut off with no loss of smoothness, and thus can be smoothly decomposed subordinate to an open cover. The latter result provides a replacement for classical partition of unity arguments in the p.c.f. fractal setting.
Preemptive entry in differentiated product markets

Summary. Models of spatial competition are typically static, and exhibit multiple free-entry equilibria. Incumbent firms can earn rents in equilibrium because any potential entrant expects a significantly lower market share (since it must fit into a niche between incumbent firms) along with fiercer price competition. Previous research has usually concentrated on the zero-profit equilibrium, at which there is normally excessive entry, and so an entry tax would improve the allocation of resources. At the other extreme, the equilibrium with the greatest rent per firm normally entails insufficient entry, so an entry subsidy should be prescribed. A model of sequential firm entry (with an exogenous order of moves) resolves the multiplicity problem but raises a new difficulty: firms that enter earlier can expect higher spatial rents, and so firms prefer to be earlier in the entry order. This tension disappears when firms can compete for entry positions. We therefore suppose that firms can commit capital early to the market in order to lay claim to a particular location. This temporal competition dissipates spatial rents in equilibrium and justifies the sequential move structure. However, the policy implications are quite different once time is introduced. An atemporal analysis of the sequential entry process would prescribe an entry subsidy, but once proper account is taken of the entry dynamics, a tax may be preferable.
Airborne video systems for agricultural assessment

Abstract Remote sensing data has not been used to its fullest potential for management of natural resources largely because these data are not readily available. Video remote sensing has been proposed as an alternative to provide near-real-time information about natural resources. This paper reviews the status and development of airborne video imaging systems and their application for resource management, with special emphasis on agriculture. Video imagery has been used to detect or assess a variety of agricultural variables such as plant species, chlorosis, grass phytomass levels, cotton and alfalfa root rot infestations, wind erosion, soil moisture and irrigated crops, soil drainage and salinity, and insect pests. The digitization and computer processing of video imagery has also been demonstrated. Presently video does not have the detailed resolution of film, but it can provide farm managers with immediately available remote sensing data that can allow them to make quick decisions concerning their operations.
Unicritical Blaschke Products and Domains of Ellipticity

Elliptic Mobius transformations of the unit disk are those for which there is a fixed point in $$\mathbb {D}$$ . It is not hard to classify which Mobius transformations are elliptic in terms of the parameters. The set of parameters can be identified with the solid torus $$S^1 \times \mathbb {D}$$ , and the set of elliptic parameters is called the domain of ellipticity. In this paper, we study the domain of ellipticity for non-trivial unicritical Blaschke products. We will also study the set corresponding to the Mandelbrot set for this family, and show how it can be obtained from the domain of ellipticity by adding one point.
Synthesis and evaluation of heterocyclic carboxamides as potential antipsychotic agents.

Heterocyclic analogues of 1192U90, 2-amino-N-(4-(4-(1,2-benzisothiazol-3-yl)-1-piperazinyl)-butyl) benzamide hydrochloride (1), were prepared and evaluated as potential antipsychotic agents. These analogues were evaluated in vitro for their binding to the dopamine D2, serotonin 5-HT2, and serotonin 5-HT1a receptors and in vivo for their ability to antagonize the apomorphine-induced climbing response in mice. Nine different types of heterocyclic carboxamides were studied in this investigation (i.e., pyridine-, thiophene-, benzothiophene-, quinoline-, 1,2,3,4-tetrahydroquinoline-, 2,3-dihydroindole-, indole-, benzimidazole-, and indazolecarboxamides). Two derivatives exhibited potent in vivo activities comparable to 1: 3-amino-N-(4-(4-(1,2-benzisothiazol-3-yl)-1-piperazinyl)butyl)-2 -pyridinecarboxamide (16) and 3-amino-N-(4-(4-(1,2-benzisothiazol-3-yl)-1-piperazinyl)butyl) -2-thiophenecarboxamide (29). Furthermore, these derivatives were found to be much less active in behavioral models predictive of extrapyramidal side effects than in the mouse climbing assay, which predicts antipsychotic activity. Carboxamides 16 and 29 were selected for further evaluation as potential backup compounds to 1.
TECHNIHADRON PRODUCTION AND DECAY AT LEP2

Abstract The simple “straw-man” model of low-scale technicolor contains light color-singlet technihadrons, which mix with the electroweak gauge bosons. We present lepton collider production rates at the parton level, and show that experiments at LEP2 may be sensitive to the presence of technirho and techniomega states with masses 10–20 GeV beyond the center-of-mass energy because of the mixing. The exact sensitivity depends on several parameters, such as the technipion mass, the technipion mixing angle, and the charge of the technifermions. In an appendix, we describe the implementation of the model into the event generator PYTHIA for particle-level studies at lepton and hadron colliders.
Ratchet cellular automata for colloids in dynamic traps

We numerically investigate the transport of kinks in a ratchet cellular automata geometry for colloids interacting with dynamical traps. We find that thermal effects can enhance the transport efficiency in agreement with recent experiments. At high temperatures we observe the creation and annihilation of thermally induced kinks that degrade the signal transmission. We consider both the deterministic and stochastic cases and show how the trap geometry can be adjusted to switch between these two cases. The operation of the dynamical trap geometry can be achieved with the adjustment of fewer parameters than ratchet cellular automata constructed using static traps.
The palladium catalyzed asymmetric addition of oxindoles and allenes: an atom-economical versatile method for the construction of chiral indole alkaloids.

The Pd-catalyzed asymmetric allylic alkylation (AAA) is one of the most useful and versatile methods for asymmetric synthesis known in organometallic chemistry. Development of this reaction over the past 30 years has typically relied on the use of an allylic electrophile bearing an appropriate leaving group to access the reactive Pd(π-allyl) intermediate that goes on to the desired coupling product after attack by the nucleophile present in the reaction. Our group has been interested in developing alternative approaches to access the reactive Pd(π-allyl) intermediate that does not require the use of an activated electrophile, which ultimately generates a stoichiometric byproduct in the reaction that is derived from the leftover leaving group. Along these lines, we have demonstrated that allenes can be used to generate the reactive Pd(π-allyl) intermediate in the presence of an acid cocatalyst, and this system is compatible with nucleophiles to allow for formation of formal AAA products by Pd-catalyzed add...
Synthesis of Fluorenes via the Palladium‐Catalyzed 5‐exo‐dig Annulation of o‐Alkynylbiaryls

The direct Pd-catalyzed intramolecular rapidly with electron-deficient benzene ring, which, in hydroarylation of o-alkynyl biaryls proceeded in highly combination with a substantial isotope effect observed, stereoselective manner producing fluorenes 2, the products of 5-exo-dig cyclization, in excellent yields. The cascade intermolecular arylation, incorporated in this transformation, allowed for efficient synthesis of fully-substituted fluorenes 12. These cyclizations proceed more rapidly with electron-deficient benzene ring, which, in combination with a substantial isotope effect observed, strongly supports a C-H activation mechanism for the key annulation step.
Convergence of Compact Ricci Solitons

We show that sequences of unit-volume compact gradient Ricci solitons converge to complete orbifold gradient solitons, assuming constraints on the L n/2 -norm of curvature, the soliton constant λ, and the auxiliary constant C 1 . The strongest results are in dimension 4, where L 2 curvature bounds are equivalent to bounds on the Euler number, given the other constraints. We obtain necessary and sufficient conditions for limits to be compact.
A framework for evaluating operations control on a metro line: integrating multiple perspectives and automatically collected train and passenger movement data

Transit operations control, the task of implementing the operations plan in daily operations on a metro line, plays a key role in service delivery because it determines the quality of the service experienced by passengers. Yet, it is one of the most poorly understood aspects of rail transit operations. Faced with a disruption or infeasibility, dispatchers typically choose between several response strategies. However, to date, it has been very difficult to evaluate the positive and negative effects of individual control strategies with respect to operations and passenger travel times under real-world conditions. This paper proposes a framework for the study of rail operations control decisions that integrates automatically collected service and passenger demand data, which are increasingly available and accessible to transit agencies. The framework supports a multiperspective analysis methodology that can inform operational policies and plans, and help operations control decision-makers choose the most appropriate strategies to manage service. By using automatically collected data, taking into consideration the operations control decision environment, and acknowledging that the reliability of the resulting service depends on many factors endogenous to it, this paper takes a distinctly different approach from previous studies, which have relied heavily on modeling, assumed simple operating contexts, and did not consider the full range of available data. Two real-world applications of the framework, where control decisions are evaluated in terms of their operational and passenger impacts, are presented. The methodology is found to be versatile and valuable in providing insights that could not have been gained otherwise. Although the framework is applied to the London Underground, its logic, structure, and procedures are applicable and transferable to other metro systems recognizing that certain specifics would need to be tailored to the available data.
CONTRIBUTION OF GIANT SPIN CLUSTERS TO THE RESISTIVITY, NEUTRON SCATTERING CROSS SECTION AND SPECIFIC HEAT IN ALLOYS : APPLICATION TO Ni-Cu

A simple model for a nondilute alloy containing giant spin clusters is used to calculate the spin contribution to the resistivity, the neutron cross section, and the specific heat ${C}_{V}$. The model is expected to be applicable to Ni-Cu alloys near the critical concentration for ferromagnetism. Intracluster interactions are treated exactly using a near-neighbor Heisenberg exchange interaction. Intercluster interactions are treated within the molecular-field approximation. It is assumed that in paramagnets there is a weak local field, which derives from the magnetic-anisotropy energy. Reasonable semiquantitative agreement with resistivity, elastic neutron scattering, and low-temperature specific-heat measurements on Ni-Cu for a range of concentrations and temperatures is obtained if the average cluster contains 50 Ni spins and if a Ni atom has a spin when eight or more of its near neighbors are also Ni. It is found that the anomalous temperature dependence of the resistivity, which behavior is common to a variety of alloy systems, can be accounted for using the present theory if the Fermi wave vector times the lattice spacing is less than \ensuremath{\cong}2. The previously unexplained behavior of the elastic neutron cross section in paramagnetic alloys can also be understood within this theoretical framework. In contrast to earlier discussions, it is shown that the spin contribution to ${C}_{V}$ is not temperature independent; in ferromagnetic alloys this contribution is found to increase with increasing temperature and in paramagnetic alloys it decreases with temperature. It is believed that this temperature dependence has, in the past, been incorrectly attributed to the electronic contribution to the specific heat. The validity of previous suggestions that the specific-heat and neutron-scattering measurements on these alloys probe different spin clusters is also questioned.
Technology variation vs. R&D uncertainty: What matters most for energy patent success?

Abstract R&D is an uncertain activity with highly skewed outcomes. Nonetheless, most recent empirical studies and modeling estimates of the potential of technological change focus on the average returns to research and development (R&D) for a composite technology and contain little or no information about the distribution of returns to R&D – which could be important for capturing the range of costs associated with climate change mitigation policies – by individual technologies. Through an empirical study of patent citation data, this paper adds to the literature on the outcomes of energy R&D by focusing on the behavior of the most successful innovations for six energy technologies, allowing us to determine whether uncertainty or differences in technologies matter most for success. We highlight two key results. First, we compare the results from an aggregate analysis of six energy technologies to technology-by-technology results. Our results show that existing work that assumes diminishing returns but assumes one generic technology is too simplistic and misses important differences between more successful and less successful technologies. Second, we use quantile regression techniques to learn more about patents that have a high positive error term in our regressions – that is, patents that receive many more citations than predicted based on observable characteristics. We find that differences across technologies, rather than differences across quantiles within technologies, are more important. The value of successful technologies persists longer than those of less successful technologies, providing evidence that success is the culmination of several advances building upon one another, rather than resulting from one single breakthrough. Diminishing returns to research activities appear most problematic during rapid increases of research investment, such as experienced by solar energy in the 1970s.
Verifiable origin of neutrino mass at TeV scale

Abstract The physics responsible for neutrino mass may reside at or below the TeV energy scale. The neutrino mass matrix in the (ν e ν μ ν gt ) basis may then be deduced from future high-energy accelerator experiments. The newly observed excess in the muon anomalous magnetic moment may also be related.
POLARIZED PARTON DISTRIBUTIONS AND THE POLARIZED GLUON ASYMMETRY

The flavor-dependent valence, sea quark and antiquark spin distributions can be determined separately from theoretical assumptions and experimental data. We have determined the valence distributions using the Bjorken sum rule and have extracted polarized sea distributions, assuming that the quarks and anti-quarks for each flavor are symmetric. Other experiments have been proposed which will allow us to completely break the SU(3) symmetry of the sea flavors. To create a physical model for the polarized gluons, we investigate the gluon spin asymmetry in a proton, . By assuming that htis is is approximately Q2 invariant, we can completely determine the x-dependence of this asymmetry, which satisfies constituent counting rules and reproduces the basic results of the Bremsstrahlung model originated by Close and Sivers. This asymmetry can be combined with the measured unpolarized gluon density, G(x,Q2) to provide a prediction for ΔG(x,Q2). Existing and proposed experiments can test both the prediction of scale-invariance for AG(x,Q2) and the nature of ΔG itself. These models will be discussed along with suggestions for specific experiments which can be performed at energies typical of HERA, RHIC and LHC to determine the nature of these polarized distributions.
Studies of iron-mediated Pauson–Khand reactions of 1,1-disubstituted-allenylsilanes: mechanistic implications for a reactive three-membered iron metallacycle

Pauson–Khand reactions of 1,1-disubstituted allenylsilanes have been explored using diiron nonacarbonyl. These studies describe the characterization of three-membered iron metallacycles as reaction-competent intermediates leading to stereoselective formation of highly functionalized 4-alkylidene-2-cyclopenten-1-ones. Studies of the reaction profile provide insights leading to the proposal of a stereoselective mechanistic pathway, which has not been previously explored. Furthermore, these reactions have been examined using computational chemistry, and these efforts have detailed the unique behavior of Fe(CO)4 and its role in Pauson–Khand processes.
Weinberg CP-violation model revisited.

Chiral properties of the weak amplitudes in the Weinberg model of CP violation are carefully treated. The CP-odd K\ensuremath{\rightarrow}2\ensuremath{\pi} amplitude is chiral-symmetry nonlinear-realization dependent, and so is the soft-pion relation. This realization dependence is canceled by the pole contribution arising from the combination of a strong K\ensuremath{\pi} vertex and a K-vacuum tadpole, so that to lowest order in chiral symmetry the physical K\ensuremath{\rightarrow}2\ensuremath{\pi} amplitude is chiral-model independent. The vacuum-insertion method is valid only in a particular realization scheme. Various CP-violating effects are then reexamined in this model. When the \ensuremath{\eta}-\ensuremath{\eta}' mixing is taken into account, \ensuremath{\epsilon}'/\ensuremath{\epsilon}\ensuremath{\approxeq}-0.007 is obtained. The electric dipole moment of a neutron due to neutral-Higgs-boson exchange and the current experimental limit are used to set an upper bound for neutral-Higgs-boson mixing. Finally, CP violation in K\ensuremath{\rightarrow}3\ensuremath{\pi} decays is discussed.
A mass formula for unimodular lattices with no roots

We derive a mass formula for n-dimensional unimodular lattices having any prescribed root system. We use Katsurada's formula for the Fourier coefficients of Siegel Eisenstein series to compute these masses for all root systems of even unimodular 32-dimensional lattices and odd unimodular lattices of dimension n ≤ 30. In particular, we find the mass of even unimodular 32- dimensional lattices with no roots, and the mass of odd unimodular lattices with no roots in dimension n ≤ 30, verifying Bacher and Venkov's enumerations in dimensions 27 and 28. We also compute better lower bounds on the number of inequivalent unimodular lattices in dimensions 26 to 30 than those afforded by the Minkowski-Siegel mass constants.
Random Design Analysis of Ridge Regression

This work gives a simultaneous analysis of both the ordinary least squares estimator and the ridge regression estimator in the random design setting under mild assumptions on the covariate/response distributions. In particular, the analysis provides sharp results on the "out-of-sample" prediction error, as opposed to the "in-sample" (fixed design) error. The analysis also reveals the effect of errors in the estimated covariance structure, as well as the effect of modeling errors, neither of which effects are present in the fixed design setting. The proofs of the main results are based on a simple decomposition lemma combined with concentration inequalities for random vectors and matrices.
Two versions of the tragedy of the commons

The commons are a one input-one output production process with increasing marginal cost. In the everage return game, each agent chooses his input contribution and total output is shared in proportion to individual contributions. In the average cost game, each agent chooses his output share and total input cost is shared in proportion to individual demands. The tragedy is that the non cooperative equilibrium results in inefficient overutilization of the technology. We prove formally the tragedy when individual preferences are convex and both goods are normal. This result has not been proved previously on such a general preference domain. We also show that overutilization is less severe in the average cost game than in the average return game.
Feedback effects of credit ratings

Abstract Rating agencies are often criticized for being biased in favor of borrowers, for being too slow to downgrade following credit quality deterioration, and for being oligopolists. Based on a model that takes into account the feedback effects of credit ratings, I show that: (i) rating agencies should focus not only on the accuracy of their ratings but also on the effects of their ratings on the probability of survival of the borrower; (ii) even when rating agencies pursue an accurate rating policy, multi-notch downgrades or immediate default may occur in response to small shocks to fundamentals; (iii) increased competition between rating agencies can lead to rating downgrades, increasing default frequency and reducing welfare.
OPTICALLY PUMPED POLARIZED ION SOURCES

Abstract The principles of operation for the optically pumped polarized hydrogen ion source based on charge exchange collisions between hydrogen ions and optically pumped electron-spin polarized alkali atoms are described. The problems associated with the use of an optically pumped-charge exchange polarized ion source for 3 He are discussed.
A least squares estimation method for the linear learning model

The author presents a new method for estimating the parameters of the linear learning model. The procedure, essentially a least squares method, is easy to carry out and avoids certain difficulties ...
The conceptual design of deck-launched waverider-configured aircraft

Abstract The results of five graduate classroom design teams are reviewed in order to assess the feasibility of carriercapable tactical waverider-configured aircraft designed for cruise Mach numbers in the range 3≤M∞≤5. The efforts of the design teams suggests that such aircraft are probably feasible for combat radii of 580 nm nm . Low-speed research to support the development of such aircraft indicates that within the subsonic flight regime, waverider planforms may be statically unstable, vortex lift may be less strong for waverider configurations than for similar simple delta wing planforms and lift, drag and pitching moment data appear to be well behaved within a large (−20°≤α≤20° data shown herein) angle-of-attack range.
On the Reduction of the Eigenvalue Problem for Spinning Axisymmetric Structures

This paper presents an entirely new method for the calculation of the natural frequencies and natural modes of a spinning axisymmetric spacecraft with flexible appendages. The approach is based on a method for the solution of the eigenvalue problem for general linear gyroscopic systems developed recently by this author. When the structure is axisymmetric, the matrices defining the eigenvalue problem are of a special type. The present paper takes advantage of the special nature of the system to reduce the order of the eigenvalue problem by a factor of two. Moreover, it develops a computational algorithm that solves the "reduced eigenvalue problem" more efficiently than existing algorithms. The method should find its application to a large variety of spinning axisymmetric structures.