cssi/SciSciGPT-SciSciNet huggingface dataset:
Resonant-Frequency-Distribution of Internal Mass Inferred From Mechanical Impedance Matrices, With Application to Fuzzy Structure Theory

The partitioning of internal mass among bands of resonant frequencies is addressed for a prototype internal vibrating structure with small damping, attached via an arbitrary number N A of attachment points to an external structure. Insofar as the dynamics of the latter are concerned, the internal structure is adequately described by a frequency-dependent impedance matrix, any given column of which lists the ratios of the 3N A force components induced by one of the attachment points' velocity components when all of the other velocity components are held to zero. The properties of matrix elements and their frequency dependence are discussed in relation to principles of mechanics, especially the requirements of translational and rotational invariance of the potential energy functions. Among the deductions are that modal masses can be defined with values calculable solely from the impedance matrix measurements, and that the modal masses sum to the total mass of the internal vibrating system.
Dust Echoes from the Ambient Medium of Gamma-Ray Bursts

Long gamma-ray bursts (GRBs) are likely associated with the collapse of massive stars, which produce dust and are born in dusty environments. Absorption and scattering of ultraviolet/X-ray photons from the prompt, optical flash, and afterglow emission of the GRB produces dust echoes. We perform time-dependent calculations of these echoes, accounting for the evolution of the dust grain distribution due to selective grain destruction by the GRB radiation and for off-axis beaming. We explore cloud configurations of differing density and size: the echo light curve and spectrum depend on the cloud radius, with larger clouds peaking at longer wavelengths. For a region that is ~3 pc in size with a density of nH ~ 103 cm-3, the echo spectrum peaks at ~3.6 μm and ~8.8 eV for the thermal and scattered components, respectively. Dust echoes should be detectable with the Very Large Telescope up to z ~ 0.1, with IRAC, on board the Spitzer Space Telescope, up to z ~ 0.2, and with NICMOS, on board the Hubble Space Telescope, up to z ~ 0.3. Furthermore, the shape of the echo light curve allows one to infer the jet opening angle, the inclination of the jet axis with respect to the line of sight, and the size of the dust-emitting region. For sources with symmetric, bipolar jets, dust echoes exhibit two bumps in the light curve, making them easily distinguishable from the rebrightening due to an underlying supernova.
Extended bond graph reticulation of the mixed initial-boundary value problem in finite hyperelasticity

Abstract Increasingly, structural systems are being designed in the finite, or large, deformation regime. Of particular importance are the hyperelastic structure elements. In this paper, the dynamics of a general hyperelastic structural element are considered subject to mixed boundary conditions, that is, mutually disjoint traction and displacement fields specified over the element boundary. Since exact formulations of this problem for arbitrary mixed boundary conditions are often intractable, a general conjugate variable approximation is developed. This conjugate variable approximation is represented, or reticulated, in terms of the extended bond graph notation. The resulting extended bond graph reticulation then serves as a “macro” reticulation for a general class of structural element behavior represented using finite element or other weighted residual approximation techniques.
The forward premium puzzle in a model of imperfect information

Abstract This paper studies the forward premium puzzle in a model with imperfect information. The model predicts fixed effects and conditional heteroskedasticity in the forward premium regression and provides a rationale for the evidence in Mayfield and Murphy [Mayfield, E.S., Murphy, R.G. 1992. Interest rate parity and the exchange risk premium, Economics Letters 40, 319–324].
Vibration Monitoring and Damage Quantification of Faulty Ball Bearings

More often than not, the rolling element bearings in rotating machinery are the mechanical components that are first prone to premature failure. Early warning of an impending bearing failure is vital to the safety and reliability of high-speed turbomachinery. Presently, vibration monitoring is one of the most applied procedures in on-line damage and failure monitoring of rolling element bearings. This paper presents results from an experimental rotor-bearing test rig with quantified damage induced in the supporting rolling element bearings. Both good and damaged radial and tapered ball bearings are used in this study. The vibration signatures due to damage at the ball elements and the inner race of the bearing are also examined. Vibration signature analyzing schemes such as frequency domain analysis, and chaotic vibration analysis (modified Poincare diagrams) are applied and their effectiveness in pinpoint damage are compared in this study. The size/level of the damage is corroborated with the vibration amplitudes to provide quantification criteria for bearing progressive failure prediction. Based on the results from this study, it is shown that the use of the modified Poincare map, based on the relative carrier speed, can provide an effective way for identification and quantification of bearing damage in rolling element bearings.
Totally skew embeddings of manifolds

We study a version of Whitney’s embedding problem in projective geometry: What is the smallest dimension of an affine space that can contain an n-dimensional submanifold without any pairs of parallel or intersecting tangent lines at distinct points? This problem is related to the generalized vector field problem, existence of non-singular bilinear maps, and the immersion problem for real projective spaces. We use these connections and other methods to obtain several specific and general bounds for the desired dimension.
A Note on Perturbative and Nonperturbative Instabilities of Twisted Circles

In this short note we compare the endpoint of tachyon condensation of twisted circles with the endpoint of nonpertubative brane nucleation in the Kaluza-Klein Melvin spacetime.
Adaptive Quadrilateral and Triangular Finite-Element Scheme for Compressible Flows

The development of an adaptive mesh refinement procedure for analyzing high-speed compressible flows using the finite-element method is described. This new adaptation procedure, which uses both quadrilateral and triangular elements, was implemented with two explicit finite-element algorithms - the two-step Taylor-Galerkin and the multistep Galerkin-Runge-Kutta schemes. A von Neumann stability analysis and a rotating 'cosine hill'problem demonstrate the instability of the Taylor-Galerkin scheme when coupled with the adaptation procedure. For the same adaptive refinement scheme, the Galerkin-Runge-Kutta procedure yields stable solutions within its explicit stability limit. The utility of this new adaptation procedure for the prediction of compressible flow features is illustrated for inviscid problems involving strong shock interactions at hypersonic speeds.
The bi-Carleson operator

We prove Lp estimates (Theorem 1.3) for the bi-Carleson operator defined below. The methods used are essentially based on the treatment of the Walsh analogue of the operator in the prequel [MTT4] of this paper, but with additional technicalities due to the fact that in the Fourier model one cannot obtain perfect localization in both space and frequency.
An atomic hydrogen propulsion system

P ERFORMANCE characteristics of a space propulsion system utilizing atomic hydrogen as a propellant are calculated. This thruster could be utilized for missions which require reliable long life operation, such as attitude correction, stationkeeping, and orbit change. A schematic diagram of the atomic hydrogen space propulsion thruster is shown in Fig. 1. An important feature of the engine is that atomic H is used as soon as it is produced by the discharge, thus eliminating the difficult problem of storage.' A mathematical model which describes the reaction chamber is presented; however, details of the microwave discharge, connecting regions, and other parts of the propulsion system are not discussed. The H2 is assumed to be completely dissociated by the microwave discharge with no impurities. The mathematical model is formulated in terms of a derived set of coupled nonlinear, first-order, differential equations governing the rate of formation and collisional dissociation of H2 and various energy loss mechanisms. These, in addition to the rate equation governing the density of atomic hydrogen in the chamber, are solved using iterative procedures. Based upon a specified flow rate of atomic hydrogen into the reaction chamber, values are given for the thrust, specific impulse, reaction chamber pressure and gas temperature, and the densities of H and H2 inside the reaction chamber for a spherical reaction chamber geometry.
Risk Reduction as the Product of Model Assessed Reliability, Confidence, and Consequence

This paper presents our methodology for verification and validation (V&V) of models, coupled to quantification of risk and risk reduction, and the use of risk, quantified as a dollar value, in the value-engineering and decision trade-off process. We begin by defining a simple measure of quantified risk, as the numerical product of three basic terms: the lower-bound model assessment of a product's reliability, multiplied by the confidence level used in the assessment, multiplied by the actuarial consequence value of the risk or risk reduction. We discuss our process for obtaining each of these three terms, and of other terms needed to complete the quantification process. An explosives impact test example is used to show the effects of model choice, data, and uncertainty methods on the resulting quantified risk reduction value. We then show how we use the quantified risk reduction value in a benefit/cost ranking method of value engineering. In this way, we can follow the simulation results from our explosiv...
Highly Stereoselective and Scalable anti-Aldol Reactions using N-(p-dodecylphenylsulfonyl)-2-Pyrrolidinecarboxamide: Scope and Origins of Stereoselectivities

A highly enantio- and diastereoselective anti-aldol process (up to >99% ee, >99:1 dr) catalyzed by a proline mimetic—N-(p-dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide—has been developed. Catalyst loading as low as 2 mol % can be employed. Use of industry-friendly solvents for this transformation as well as neat reaction conditions have been demonstrated. The scope of this transformation on a range of aldehydes and ketones is explored. Density functional theory computations reveal that the origins of enhanced diastereoselectivity are due to the presence of nonclassical hydrogen bonds between the sulfonamide, the electrophile, and the catalyst enamine that favor the major anti-Re aldol TS in the Houk−List model.
Stellar spectroscopy: Fermions and holographic Lifshitz criticality

Electron stars are fluids of charged fermions in Anti-de Sitter spacetime. They are candidate holographic duals for gauge theories at finite charge density and exhibit emergent Lifshitz scaling at low energies. This paper computes in detail the field theory Green’s function G R(ω,k) of the gauge-invariant fermionic operators making up the star. The Green’s function contains a large number of closely spaced Fermi surfaces, the volumes of which add up to the total charge density in accordance with the Luttinger count. Excitations of the Fermi surfaces are long lived for ω ≲ k z. Beyond ω ∼ k z the fermionic quasiparticles dissipate strongly into the critical Lifshitz sector. Fermions near this critical dispersion relation give interesting contributions to the optical conductivity.
The oscillator strength in atomic absorption spectroscopy

Abstract The role of the oscillator strength in atomic absorption spectroscopy, and in particular in absolute elemental analysis by atomic absorption, is discussed. A universal method for determining atomic lifetimes, and hence absolute oscillator strengths of atomic resonance lines, for almost any element in the Periodic Table is described. It is shown that for the idealized conditions of a pure natural-broadened absorption line and a monochromatic emission line, the peak atomic absorption coefficient is independent of the oscillator strength and that the oscillator strength enters into an atomic absorption signal only through extraneous broadening processes such as Doppler, collisional, and transit-time broadening. An atomic absorption experiment, based on samples of near-stationary laser-cooled atoms and a near-monochromatic diode-laser light source, that satisfies the requirements for “oscillator-strength-free” atomic absorption is described.
Ideals of adjacent minors

Abstract We give a description of the minimal primes of the ideal generated by the 2×2 adjacent minors of a generic matrix. We also compute the complete prime decomposition of the ideal of adjacent m×m minors of an m×n generic matrix when the characteristic of the ground field is zero. A key intermediate result is the proof that the ideals which appear as minimal primes are, in fact, prime ideals. This introduces a large new class of mixed determinantal ideals that are prime.
Results from deuterium-tritium tokamak confinement experiments

Recent scientific and technical progress in magnetic fusion experiments has resulted in the achievement of plasma parameters (density and temperature) which made possible the production of significant bursts of fusion power from deuterium-tritium fuels and the first studies of the physics of burning plasmas. The key scientific issues in studying the reacting plasma core are plasma confinement, magnetohydrodynamic (MHD) stability, and the confinement and loss of energetic fusion products from the reacting fuel ions. Progress in the development of regimes of operation that both have good confinement and are MHD stable has made possible a broad study of problems in burning-plasma physics. The technical and scientific results from deuterium-tritium experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) are reviewed, with particular emphasis on alpha-particle physics issues.
Pion exchange currents and nuclear charge form factors

Abstract The effect of the pion exchange current due to the Born term in the photoproduction amplitude on the charge form factors and distributions of 4 He, 16 O and 40 Ca is calculated in the simple harmonic oscillator shell model. The exchange current contribution is most notable in the case of the α-particle while it is rather unimportant in 16 O and 40 Ca. The contribution to the nuclear mean square radius is small (≈ 0.03 fm 2 ) and roughly independent of the mass number.
Radiative tau lepton pair production as a probe of anomalous electromagnetic couplings of the tau

Abstract We calculate the squared matrix element for the process e + e − → τ + τ − γ allowing for anomalous magnetic and electric dipole moments at the ττγ vertex. No interferences are neglected and no approximations of light fermion masses are made. We show that anomalous moments affect not only the cross section, but also the shape of the photon energy and angular distributions. We also demonstrate that in the case of the anomalous magnetic dipole moment, the contribution from interference involving Standard Model and anomalous amplitudes is significant compared to the contribution from anomalous amplitudes alone. A program to perform the calculation is available and it may be employed as a Monte Carlo generator.
Spontaneous creation of inflationary universes and the cosmic landscape

We study some gravitational instanton solutions that offer a natural realization of the spontaneous creation of inflationary universes in the brane world context in string theory. Decoherence due to couplings of higher (perturbative) modes of the metric as well as matter fields modifies the Hartle-Hawking wavefunction for de Sitter space. Generalizing this new wavefunction to be used in string theory, we propose a principle in string theory that hopefully will lead us to the particular vacuum we live in, thus avoiding the anthropic principle. As an illustration of this idea, we give a phenomenological analysis of the probability of quantum tunneling to various stringy vacua. We find that the preferred tunneling is to an inflationary universe (like our early universe), not to a universe with a very small cosmological constant (i.e., like today's universe) and not to a 10-dimensional (or a higher dimensional supercritical) uncompactified de Sitter universe. Some solutions are interesting as they offer a cosmological mechanism for the stabilization of extra dimensions during the inflationary epoch.
A Relativistic-Plasma Compton Maser

A relativistic pair-plasma that contains a high excitation of electrostatic turbulence could produce intense radiation by stimulated scattering at a brightness temperature in excess of 1020 K. Important relativistic effects would include the broadband frequency response of the plasma and Compton-boosting of the scattered radiation. In radio-frequency relativistic plasma, the optical depth can be as small as tens of meters. When the plasma wave excitation is one-dimensional and particle distributions have T⊥ T||, the frequency-dependent angular distribution of the emission exhibits characteristics of pulsar emission.
An index for closed orbits in Beltrami fields

Abstract We consider the class of Beltrami fields (eigenfields of the curl operator) on three-dimensional Riemannian solid tori: such vector fields arise as steady incompressible inviscid fluids and plasmas. Using techniques from contact geometry, we construct an integer-valued index for detecting closed orbits in the flow which are topologically inessential (they have winding number zero with respect to the solid torus). The most important feature of the index is its computability: it can be rigorously determined from a C 1 -approximation to the vector field on any meridional disc of the solid torus. As a result, we obtain a test for detecting the non-existence of a global cross-section to the 3D flow via purely 2D information.
A new high density recording system: the IBM 1311 disk storage drive with interchangeable disk packs

The development of the 1311 Disk Storage Drive began with the realization that although systems were available to meet the data processing requirements of many businesses, these systems were too big for small industries and businesses. Files which had been announced or were in development up to this time had large capacities with fast data handling capabilities but could not meet the low cost objective necessary for the smaller users.
de Finetti’s theory of probability and its Jaynesian critique

For aesthetic, strategic and pragmatic reasons, Jaynes (Probability: The Logic of Science, Cambridge University Press, Cambridge, 2003, Appendix A) objects to Bruno de Finetti’s founding of probability theory on the basis of the notion of coherence. In this paper an attempt is made to diffuse this critique, as well as to point out, briefly, that these, and the remarks on a variety of foundational issues in mathematics and metamathematics (op.cit, Appendix B) are misguided.
Antileukemic Activity of 2-Bis(2-methylthio)vinyl-1-methylquinolinium Iodides

Reaction of 1-methylquinolinium-2-dithioacetic acid zwitterions with excess methyl iodide in dimethylformamide gave the corresponding bis(2-methylthio)vinyl derivatives. These compounds were more soluble in both aqueous and organic media than the dithioacetic acid zwitterions but showed comparable antileukemic activity in mice. Reaction with morpholine converted a bis(2-methylthio)vinyl derivative almost quantitatively to the 2-mono(methylthio)-2-morpholino derivative. Leukemia cell culture studies of the 6-methyl derivative showed no effect on cell cycle processes.
Deep Inelastic Scattering and Gauge/String Duality

We study deep inelastic scattering in gauge theories which have dual string descriptions. As a function of gN we find a transition. For small gN, the dominant operators in the OPE are the usual ones, of approximate twist two, corresponding to scattering from weakly interacting partons. For large gN, double-trace operators dominate, corresponding to scattering from entire hadrons (either the original `valence' hadron or part of a hadron cloud.) At large gN we calculate the structure functions. As a function of Bjorken x there are three regimes: x of order one, where the scattering produces only supergravity states; x small, where excited strings are produced; and, x exponentially small, where the excited strings are comparable in size to the AdS space. The last regime requires in principle a full string calculation in curved spacetime, but the effect of string growth can be simply obtained from the world-sheet renormalization group.
Regioselective and Stereospecific Azidation of 1,2- and 1,3-Diols by Azidotrimethylsilane via a Mitsunobu Reaction

A one-pot regio- and stereospecific azidation reaction of 1,2- and 1,3-diols with azidotrimethylsilane (Me3SiN3) via a Mitsunobu reaction has been achieved. With 1,2- and 1,3-diols, the reaction of triphenylphosphine, diisopropyl azodicarboxylate, and Me3SiN3 in dichloromethane gave regioselective azidation at C-2 and C-3, respectively, in good yield (74−90% combined yield of 1a + 1b or of 2a + 2b). However, application of the same reaction conditions to a 1,4-diol led to the exclusive formation of the cyclic ether. The regioselectivity of this one-pot reaction is influenced by the solvent, the degree of steric bulk at C-2 of the 1,2-diol or at C-3 of the 1,3-diol, and the presence of electron-donating and electron-withdrawing groups near the secondary carbinol carbon. This selectivity is discussed in terms of the mechanistic model proposed by Mathieu-Pelta and Evans (Mathieu-Pelta, I.; Evans, S. A., Jr. J. Org. Chem. 1992, 57, 3409−3413), which involves reaction of the dioxaphospholane intermediate with ...
The utility of coherent states and other mathematical methods in the foundations of affine quantum gravity

Affine quantum gravity involves (i) affine commutation relations to ensure metric positivity, (ii) a regularized projection operator procedure to accommodate first-and second-class quantum constraints, and (iii) a hard-core interpretation of nonlinear interactions to understand and potentially overcome nonrenormalizability. In this program, some of the less traditional mathematical methods employed are (i) coherent-state representations, (ii) reproducing kernel Hilbert spaces, and (iii) functional-integral representations involving a continuous-time regularization. Of special importance is the profoundly different integration measure used for the Lagrange multiplier (shift and lapse) functions. These various concepts are first introduced on elementary systems to help motivate their application to affine quantum gravity.
Witnessing Your Own Cognitive Bias: A Compendium of Classroom Exercises

ABSTRACT: Accounting and auditing professors continually stress the importance of effective judgment and decision making (JDM), yet few accounting programs or textbooks discuss the biases that may impact an individual's ability to exercise high-quality professional judgment. In recent years, KPMG (Ranzilla, Chevalier, Herrmann, Glover, and Prawitt 2011) and the Committee of Sponsoring Organizations of the Treadway Commission (KPMG, Glover, and Prawitt 2012) addressed this gap at the corporate level by publishing guidance for accounting professionals and board members on how to identify and mitigate common judgment biases, yet there remain few resources designed for accounting students. This collection of exercises enables instructors to introduce the topic of effective JDM in the classroom. It provides students with the opportunity to identify bias in their own judgments by highlighting five frequently occurring biases that adversely impact business judgments (i.e., availability, anchoring, overconfidence...
Governance quality and privately negotiated stock repurchases: Evidence of agency conflict

Abstract This study examines the impact of shareholder rights on the wealth effects of privately negotiated stock repurchases. Our results show that wealth gains are lower when shareholder rights are more suppressed. We also find that the premium paid for shares is inversely related to the strength of shareholder rights, and this suggests that managers pay higher premiums when shareholder rights are more restricted. These findings imply that managers use shareholders’ funds to eliminate blockholders who are more likely to monitor them when shareholder rights are relatively weak, thereby entrench themselves. Consistent with this view, we further show that significant positive abnormal long-run returns after private stock repurchases are limited to firms with stronger shareholder protection. Overall, the evidence is consistent with the predictions of agency theory.
Magnetic transition and spin fluctuations in the unconventional antiferromagnetic compound Yb3Pt4

Muon spin rotation and relaxation measurements have been carried out on the unconventional antiferromagnet Yb3Pt4. Oscillations are observed below TN = 2.22(1) K, consistent with the antiferromagnetic (AFM) Neel temperature observed in bulk experiments. In agreement with neutron diffraction experiments the oscillation frequency ωμ(T)/2π follows an S = 1/2 mean-field temperature dependence, yielding a quasistatic local field of 1.71(2) kOe at T = 0. A crude estimate gives an ordered moment of ~ 0.66 μB at T = 0, comparable to 0.81 μB from neutron diffraction. As from above the dynamic relaxation rate λd exhibits no critical slowing down, consistent with a mean-field transition. In the AFM phase a T-linear fit to λd(T), appropriate to a Fermi liquid, yields highly enhanced values of λd/T and the Korringa constant Kμ2T/λd, with Kμ the estimated muon Knight shift. A strong suppression of λd by applied field is observed in the AFM phase. These properties are consistent with the observed large Sommerfeld–Wilson and Kadowaki–Woods ratios in Yb3Pt4 (although the data do not discriminate between Fermi-liquid and non-Fermi-liquid states), and suggest strong enhancement of q≈0 spin correlations between large-Fermi-volume band quasiparticles in the AFM phase of Yb3Pt4.
Experimental and Finite Element Analysis of Stand-Off Layer Damping Treatments for Beams

Passive stand-off layer (PSOL) and slotted stand-off layer (SSOL) damping treatments are presently being implemented in many commercial and defense designs. In a PSOL damping treatment, a stand-off or spacer layer is added to a conventional passive constrained layer damping treatment. In an SSOL damping treatment, slots are included in the stand-off layer. A set of experiments using PSOL and SSOL beams in which the geometric properties of the stand-off layer were varied was conducted to analyze the contribution of the stand-off layer to the overall system damping. This set of experiments measured the frequency response functions for a series of beams in which the total slotted area of the stand-off layer was held constant while the number of slots in the stand-off layer was increased for a constant stand-off layer material. Finite element analysis models were developed in ANSYS to compare the predicted frequency response functions with the experimentally measured frequency response functions for the beams treated with PSOL and SSOL damping treatments. In these beams, the bonding layers used to fabricate these treatments were found to have a measurable and significant effect on the frequency response of the structure. The finite element model presented here thus included an epoxy layer between the base beam and the stand-off layer, a contact cement layer between the stand-off layer and the viscoelastic layer, and a method for modeling delamination.Copyright © 2007 by ASME
Time-dependent Force-free Pulsar Magnetospheres: Axisymmetric and Oblique Rotators

Magnetospheres of many astrophysical objects can be accurately described by the low-inertia (or ''force-free'') limit of MHD. We present a new numerical method for solution of equations of force-free relativistic MHD based on the finite-difference time-domain (FDTD) approach with a prescription for handling spontaneous formation of current sheets. We use this method to study the time-dependent evolution of pulsar magnetospheres in both aligned and oblique magnetic geometries. For the aligned rotator we confirm the general properties of the time-independent solution of Contopoulos et al. (1999). For the oblique rotator we present the 3D structure of the magnetosphere and compute, for the first time, the spindown power of pulsars as a function of inclination of the magnetic axis. We find the pulsar spindown luminosity to be L {approx} ({mu}{sup 2}{Omega}{sub *}{sup 4}/c{sup 3})(1 + sin{sup 2}{alpha}) for a star with the dipole moment {mu}, rotation frequency {Omega}{sub *}, and magnetic inclination angle {alpha}. We also discuss the effects of current sheet resistivity and reconnection on the structure and evolution of the magnetosphere.
Near-Infrared Observations of Powerful High-Redshift Radio Galaxies: 4C 40.36 and 4C 39.37

We present near-infrared imaging and spectroscopic observations of two Fanaroff-Riley type II high-redshift radio galaxies (HzRGs), 4C 40.36 (z = 2.3) and 4C 39.37 (z = 3.2), obtained with the Hubble Space Telescope and the Keck and Hale Telescopes. High-resolution images were taken with filters both in and out of strong emission lines, and together with the spectroscopic data, the properties of the line and continuum emissions were carefully analyzed. Our analysis of 4C 40.36 and 4C 39.37 shows that strong emission lines (e.g., [O III] λ5007 and Hα+[N II]) contribute to the broadband fluxes much more significantly than previously estimated (80% vs. 20%–40%) and that when the continuum sources are imaged through line-free filters, they show an extremely compact morphology with a high surface brightness. If we use the R^(1/4)-law parameterization, their effective radii (r_e) are only 2h_(50)^(-1) to 3h_(50)^(-1) kpc, while their rest-frame B-band surface brightnesses at r_e are I_e(B) ~ 18 mag arcsec^(-2). Compared with z ~ 1 3CR radio galaxies, the former is 3–5 times smaller, while the latter is 1–1.5 mag brighter than what is predicted from the I_e(B)-r_e correlation. Although exponential profiles produce equally good fits for 4C 40.36 and 4C 39.37, this clearly indicates that with respect to the z ~ 1 3CR radio galaxies, the light distribution of these two HzRGs is much more centrally concentrated. Spectroscopically, 4C 40.36 shows a flat (f_ν = const.) continuum, while 4C 39.37 shows a spectrum as red as that of a local giant elliptical galaxy. Although this difference may be explained in terms of a varying degree of star formation, the similarities of their surface brightness profiles and the submillimeter detection of 4C 39.37 might suggest that the intrinsic spectra is equally blue (young stars or an active galactic nuclei) and that the difference is the amount of reddening.
Schottky barriers: An effective work function model

The experimental observations of metallurgical interactions between compound semiconductor substrates and metallic or oxide overlayers have stimulated a new model of Fermi level ’’pinning’’ at these interfaces. This model assumes the standard Schottky picture of interface band alignment, but that the interface phases involved are not the pure metal or oxide normally assumed by other models. For both III‐V and II‐VI compounds, the barrier height to gold is found to correlate well with the anion work function, suggesting the interface phases are often anion rich. This correlation holds even for cases in which the ’’common anion rule’’ fails, and explains both successes and failures of this earlier model.
Discovery of Radio/X-Ray/Optical-resolved Supernova Remnants in the Center of the Andromeda Galaxy

We have detected a spatially resolved supernova remnant (SNR) in the center of the Andromeda galaxy, in radio, X-ray, and optical wavelengths. These observations provide the highest spatial resolution imaging of a radio/X-ray/optical SNR in that galaxy to date. The multiwavelength morphology, radio spectral index, X-ray colors, and narrowband optical imaging are consistent with a shell-type SNR. A second SNR is also seen resolved in both radio and X-ray. By comparing the morphological structure of the SNRs in different wavelengths and with that in our own Galaxy, we can study the shock morphologies of SNRs in the Andromeda galaxy. The proximity of the SNRs to the core suggests a high interstellar medium density in the vicinity of the SNRs in the center of the Andromeda galaxy.
THE COEFFICIENTS OF THE HOMFLYPT AND THE KAUFFMAN POLYNOMIALS ARE POINTWISE LIMITS OF VASSILIEV INVARIANTS

The Vassiliev conjecture states that the Vassiliev invariants are dense in the space of all numerical link invariants in the sense that any link invariant is a pointwise limit of Vassiliev invariants. In this article, we prove that the Vassiliev conjecture holds in the case of the coefficients of the HOMFLY and the Kauffman polynomials.
Quizz: targeted crowdsourcing with a billion (potential) users

We describe Quizz, a gamified crowdsourcing system that simultaneously assesses the knowledge of users and acquires new knowledge from them. Quizz operates by asking users to complete short quizzes on specific topics; as a user answers the quiz questions, Quizz estimates the user's competence. To acquire new knowledge, Quizz also incorporates questions for which we do not have a known answer; the answers given by competent users provide useful signals for selecting the correct answers for these questions. Quizz actively tries to identify knowledgeable users on the Internet by running advertising campaigns, effectively leveraging the targeting capabilities of existing, publicly available, ad placement services. Quizz quantifies the contributions of the users using information theory and sends feedback to the advertisingsystem about each user. The feedback allows the ad targeting mechanism to further optimize ad placement. Our experiments, which involve over ten thousand users, confirm that we can crowdsource knowledge curation for niche and specialized topics, as the advertising network can automatically identify users with the desired expertise and interest in the given topic. We present controlled experiments that examine the effect of various incentive mechanisms, highlighting the need for having short-term rewards as goals, which incentivize the users to contribute. Finally, our cost-quality analysis indicates that the cost of our approach is below that of hiring workers through paid-crowdsourcing platforms, while offering the additional advantage of giving access to billions of potential users all over the planet, and being able to reach users with specialized expertise that is not typically available through existing labor marketplaces.
Optimum sizing of distributed generation and storage capacity in smart households

In the near future, a smart grid will accommodate customers who are prepared to invest in generation-battery systems and employ energy management systems in order to cut down on their electricity bills. The main objective of this paper is to determine the optimum capacity of a customer's distributed-generation system (such as a wind turbine) and battery within the framework of a smart grid. The proposed approach involves developing an electricity management system based on stochastic variables, such as wind speed, electricity rates, and load. Then, a hybrid stochastic method based on Monte Carlo simulation and particle swarm optimization is proposed to determine the optimum size of the wind generation-battery system. Several sensitivity analyses demonstrate the proper performance of the proposed method in different conditions.
Sensor Selection Based on Generalized Information Gain for Target Tracking in Large Sensor Networks

In this paper, sensor selection problems for target tracking in large sensor networks with linear equality or inequality constraints are considered. First, we derive an equivalent Kalman filter for sensor selection, i.e., generalized information filter. Then, under a regularity condition, we prove that the multistage look-ahead policy that minimizes either the final or the average estimation error covariances of next multiple time steps is equivalent to a myopic sensor selection policy that maximizes the trace of the generalized information gain at each time step. Moreover, when the measurement noises are uncorrelated between sensors, the optimal solution can be obtained analytically for sensor selection when constraints are temporally separable. When constraints are temporally inseparable, sensor selections can be obtained by approximately solving a linear programming problem so that the sensor selection problem for a large sensor network can be dealt with quickly. Although there is no guarantee that the gap between the performance of the chosen subset and the performance bound is always small, numerical examples suggest that the algorithm is near-optimal in many cases. Finally, when the measurement noises are correlated between sensors, the sensor selection problem with temporally inseparable constraints can be relaxed to a Boolean quadratic programming problem which can be efficiently solved by a Gaussian randomization procedure along with solving a semi-definite programming problem. Numerical examples show that the proposed method is much better than the method that ignores dependence of noises.
Pension Type and Retirement Wealth

In this article I analyze the effect of a shift from defined-benefit pensions to defined-contribution pensions on retirement wealth. Regressions results suggest that workers with a defined-benefit pension appear to have more retirement resources than those who either have no pension or have a defined-contribution pension, although individual savings is generally insufficient. I use the Health and Retirement Survey (HRS), which contains data on individuals 51 to 61 years of age.
Effects of thermal radiation on the dynamics of binary NEAs

Abstract The Yarkovsky force, produced when thermal radiation is re-emitted asymmetrically, causes significant orbital evolution of asteroids in the 10 m–10 km size range. When acting on a non-spherical body, the momentum carried by this radiation generally produces a torque, called the YORP effect, which may be important in re-orienting asteroidal spins. Here we explore a related effect, the “binary YORP” (BYORP), that can modify the orbit of a synchronously rotating secondary in a binary system. It arises because a locked secondary is effectively an asymmetric appendage of the primary. It should be particularly important for Near-Earth Asteroids (NEAs) owing to their small sizes, proximity to the Sun, and benign collisional environment. To estimate BYORP's strength, we subjected 100 random Gaussian spheroids to the thermal radiation model of Rubincam (2000, Radiative spin-up and spin-down of small asteroids, Icarus, 148, 2–11). For most shapes, a significant torque arose on the secondary's orbit, typically modifying the orbit's size, eccentricity and inclination in less than 10 5 years, for components of 1 and 0.3 km radii, separated by 2 km, at 1 AU, each of density 1750 kg m −3 . Together YORP and BYORP are capable of synchronizing secondaries and circularizing orbits, making tidal dissipation unnecessary to explain the evolved state of observed NEA pairs. However, BYORP's rapid timescale poses a problem for the abundance of observed NEA binaries, since their formation rate is thought to be much slower. We consider and reject the following resolutions of this quandary: (i) the approximation using Gaussian spheroids inadequately models YORP; (ii) most secondaries are not synchronous, but inhabit other spin-orbit resonances (very unlikely); (iii) tidal dissipation is much more efficient than previously estimated, and thus capable of stabilizing observed systems; and (iv) moderately close encounters with planets can re-orient secondaries, turning BYORP into a slower, random-walk process. Finally, we speculate that most observed binary NEAs are in a stable state in which the obliquity-changing torques of YORP (acting on the primary) and BYORP cancel out, and that those systems must be close to 55° inclination, where the momentum-changing torques of both YORP and BYORP tend to be very small. Some retrograde systems might develop such that the nodes precess at a Sun-synchronous rate, while some prograde ones might move into the “evection” resonance. All three of these hypotheses can be tested directly by comparison with the i , Ω and ϖ observed for NEA binaries.
EXPECTATIONS FROM A MICROLENSING SEARCH FOR PLANETS

Abstract The statistical distribution of the masses of planets about stars between the Sun and the center of the Galaxy is constrained to within a factor of 3 by an intensive search for planets during microlensing events. Projected separations in terms of the lens Einstein ring radius yield a rough estimate of the distribution of planetary semimajor axes with planetary mass. The search consists of following ongoing stellar microlensing events involving sources in the center of the Galaxy lensed by intervening stars with high-time-resolution, 1% photometry in two colors in an attempt to catch any short-time-scale planetary perturbations of the otherwise smooth lightcurve. It is assumed that 3000 events are followed over an 8-year period, but with half of the lenses, those that are members of binary systems, devoid of planets. The remaining 1500 lenses have Solar System-like distributions of four or five planets. The expectations from the microlensing search are extremely assumption dependent, with 56, 138, and 81 planets being detected for three sets of assumptions involving how the planetary masses and separations vary with lens mass. The events can be covered from 54 to 62% of the time on average by high-time-resolution photometry from a system of three or four dedicated 2-m telescopes distributed in longitude, so 38 to 46% of the detectable small-mass planets (very short perturbations of the lightcurve) will be missed. But perturbations comparable to a day in length mean all of the detectable Jupiters and Saturns will in fact be detected as will a large fraction of the Uranuses. The ground-based observational technique is robust, and although no follow-up studies can be made, meaningful statistics on planetary masses and separations can be inferred from such an intensive search. These statistics, like the inferred data set, will also be dependent on the assumptions about the nature of the set of planetary systems. More precisely, the detection of few Earths gives meaningful statistics for the occurrence of Earths in the lensing zone, but does not exclude Earths very close to their stars. But, finding few Jupiters, Saturns, and Uranuses would have profound implications independent of reasonable assumptions about the nature of the systems. Finding most of many giant and sub-giant planets outside the Einstein ring radii of their respective stars may be a better indicator of the frequency of Earth-mass planets than direct detection of a few of the latter.
Moduli of products of curves

Some technical results on the deformations of varieties of general type and on permanence of semi-log-canonical singularities are proved. These results are applied to show that the connected component of the moduli space of stable surfaces containing the moduli point of a product of stable curves is the product of the moduli spaces of the curves, assuming the curves have different genera. An application of this result shows that even after compactifying the moduli space and fixing numerical invariants, the moduli spaces are still very disconnected.
Social Connections and Group Banking

Lending to the poor is expensive due to high screening, monitoring and enforcement costs. Group lending advocates believe lenders overcome this by harnessing social connections. Using data from FINCA-Peru, I exploit a quasi-random group formation process to find evidence of peers successfully monitoring and enforcing joint-liability loans. Individuals with stronger social connections to their fellow group members (i.e., either living closer or being of a similar culture) have higher repayment and higher savings. Furthermore, I observe direct evidence that relationships deteriorate after default, and that through successful monitoring, individuals know who to punish and who not to punish after default.
Liquid droplet radiator performance studies

By making use of droplets rather than solid surfaces to radiate waste heat in space, the liquid-droplet radiator (LDR) achieves a radiating area/mass much larger than that of conventional radiators which use fins or heat pipes. The light-weight potential of the LDR is shown to be limited primarily by the radiative properties of the droplets. The requirement that the LDR heat-transfer fluid have a very low vapor pressure limits the choice of fluids to relatively few several liquid metals and a silicone fluid are the only suitable candidates so far identified. An experimental determination of the emittance of submillimeter droplets of the silicon fluid indicates that an LDR using this fluid at temperatures of 275-335 K would be about 10 times lighter than the lightest solid-surface radiators. Although several liquid metals appear to offer excellent performance in LDR applications at temperatures between 200 and 975 K, experimental determination of liquid-metal emissivities is needed for a conclusive assessment.
Design and synthesis of hydrophobic, bulky χ2-constrained phenylalanine and naphthylalanine derivatives

Abstract A series of novel hydrophobic, bulky χ 2 -constrained phenylalanine and naphthylalanine derivatives were designed and synthesized. Asymmetric hydrogenations of α-enamides using Burk's DuPHOS-based Rh(I) catalysts generated high enantiomerically pure α-amino acid derivatives, which subsequently underwent Suzuki cross couplings with boronic acid derivatives to afford these aromatic substituted amino acids in high yields and with high enantioselectivity.
Real-Time Visual Tracking Using Geometric Active Contours and Particle Filters

Image processing and flltering are essential elements for the visual tracking system in an unmanned aerial vehicle. This paper presents visual tracking methodology based on particle flltering in the framework of a fast implementation of the Chan-Vese active contour model. The fast implementation greatly improves the computational time of the segmentation process. We have tested particle flltering using this fast active contour model, and the flltering algorithm has shown the ability to robustly track an aerial target under varied conditions. The computational speed of the algorithm has allowed us to employ it for formation ∞ight among UAVs. We have also demonstrated the utility of the flltering algorithm for multiple target tracking in the presence of occlusions.
Stein Estimation for Spherically Symmetric Distributions: Recent Developments

This paper reviews advances in Stein-type shrinkage estima- tion for spherically symmetric distributions. Some emphasis is placed on developing intuition as to why shrinkage should work in location problems whether the underlying population is normal or not. Consid- erable attention is devoted to generalizing the "Stein lemma" which underlies much of the theoretical development of improved minimax estimation for spherically symmetric distributions. A main focus is on distributional robustness results in cases where a residual vector is available to estimate an unknown scale parameter, and, in particu- lar, in finding estimators which are simultaneously generalized Bayes and minimax over large classes of spherically symmetric distributions. Some attention is also given to the problem of estimating a location vector restricted to lie in a polyhedral cone.