cssi/SciSciGPT-SciSciNet huggingface dataset:
An integral equation approach to the analysis of finite microstrip antennas: volume/surface formulation

An E-field integral equation for the analysis of finite printed circuit antennas with multiple dielectric regions is developed. In this analysis, the ground plane is considered to be finite. The dielectric substrates may be either lossless or lossy, and they may be inhomogeneous but must be finite. The equivalence principle is used to replace all conducting bodies by equivalent surface electric currents and all dielectrics by equivalent volume polarization currents. The respective boundary conditions on the dielectrics and the conductors are utilized to solve for the electric current on the entire structure. Typical results are presented to illustrate the potential of this method. >
The effect of pension design on employer costs and employee retirement choices: Evidence from Oregon☆

Abstract We use administrative data from Oregon's Public Employees Retirement System (PERS) to study the effect of pension design on employer costs and employee retirement-timing decisions. During our 1990–2003 sample period, PERS calculates each member's retirement benefit using up to three different formulas (defined benefit (DB), defined contribution (DC), and a combination of DB and DC), and PERS pays the maximum benefit for which the member is eligible. We show that this “maximum benefit” calculation results in average ex post retirement benefits that are 54% higher than if they had been calculated using only the DB formula and that employees receiving DC benefits are significantly more likely than employees receiving DB benefits to retire before the plan's normal retirement age. Monte Carlo simulations verify that the higher costs could have been predicted at the start of our sample period. Exploiting exogenous plan changes, we show that employees respond to within-year variation in their retirement incentives and, consistent with peer effects, that they respond more strongly to these incentives when more of their coworkers face similar incentives. Finally, consistent with the emerging literature on financial mistakes by households, we show that a small but noteworthy fraction of retirees would have benefited from shifting their retirements by as little as one month.
Total Synthesis of Platensimycin and Related Natural Products

Platensimycin is the flagship member of a new and growing class of antibiotics with promising antibacterial properties against drug-resistant bacteria. The total syntheses of platensimycin and its congeners, platensimycins B1 and B3, platensic acid, methyl platensinoate, platensimide A, homoplatensimide A, and homoplatensimide A methyl ester, are described. The convergent strategy developed toward these target molecules involved construction of their cage-like core followed by attachment of the various side chains through amide bond formation. In addition to a racemic synthesis, two asymmetric routes to the core structure are described: one exploiting a rhodium-catalyzed asymmetric cycloisomerization, and another employing a hypervalent iodine-mediated de-aromatizing cyclization of an enantiopure substrate. The final two bonds of the core structure were forged through a samarium diiodide-mediated ketyl radical cyclization and an acid-catalyzed etherification. The rhodium-catalyzed asymmetric reaction invo...
Synthesis of Substituted Oxindoles from α-Chloroacetanilides via Palladium-Catalyzed C−H Functionalization

A novel method for the synthesis of oxindoles is described. In the presence of catalytic palladium acetate and 2-(di-tert-butylphosphino)biphenyl, α-chloroacetanilides are converted to oxindoles in good to excellent yields with high functional group compatibility using triethylamine as a stoichiometric base. The cyclization is highly regioselective, obviating the need for prefunctionalized arenes. Plausible mechanistic pathways for the reaction are discussed.
Quantum- and quasi-Plücker coordinates

Abstract We demonstrate a passage from the “quasi-Plucker coordinates” of Gelfand and Retakh, to the quantum Plucker coordinates built from q-generic matrices. In the process, we rediscover the defining relations of the quantum Grassmannian of Taft and Towber and provide that algebra with more concrete geometric origins.
On continuum incidence problems related to harmonic analysis

Abstract We consider averaging operators over curves and surfaces satisfying the rotational curvature condition of Phong and Stein. Using combinatorial arguments restricted weak-type versions of the standard estimates are obtained under weaker assumptions on the regularity of these surfaces. We also consider maximal functions over circles in the plane and obtain a simpler proof of Wolff's endpoint result.
Reasoning on the Location of Components for Assembly Packaging

The process of locating components in an available space while satisfying spatial relationships among the components is called packaging. The task requires extensive spatial reasoning about geometric shapes. It is a generic design task common to many domains. It is also very time-consuming, especially as machines become more compact and complex. This paper describes progress toward automation of the packaging problem. An approach is proposed to determine the optimal locations of components in an assembly from spatial relationships between the components. The approach utilizes a novel combination of optimization and solid modeling techniques.
Holomorphic triangles and invariants for smooth four-manifolds

Abstract In earlier articles, the authors introduced invariants for closed, oriented three-manifolds, defined using a variant of Lagrangian Floer homology in the symmetric products of Riemann surfaces. The aim of this article is to introduce invariants of oriented, smooth four-manifolds, built using these Floer homology groups. This four-dimensional theory also endows the corresponding three-dimensional theories with additional structure: an absolute grading of certain of its Floer homology groups.
Crystal growth of calcium carbonate in the invertebrates

Mineral formation is widely observed in living systems and twenty four inorganic compounds have been found to date to be present in various organisms (Lowenstam, 1974; Lowenstam and Margulis, 1980). Of these, calcium carbonate is the most conxnon and occurs as calcite and/or aragonite, and also to a lesser extent as amorphous CaC03, vaterite, or monohydrocalcite (Watabe, 1974; Watabe and Dunkelberger, 1979; Lowenstam and Margulis, 1980). The size, habit, and the state of aggregate of polymorphic species of calcium carbonate which build calcareous structures vary by the organisms; however, each organism normally maintains specific characteristics of these crystalline patterns. In the following sections, we shall examine the crystalline characteristics of calcareous structures, the sites of their formation, nucleation and growth of crystals, the organic matrix and other factors controlling the crystalline patterns. Discussions will be limited to those structures in the invertebrate animals in which the majority of the CaCO 3 crystals are concentrated.
Product platform design through sensitivity analysis and cluster analysis

Scale-based product platform design consists of platform configuration to decide which variables are shared among which product variants, and selection of the optimal values for platform (shared) and non-platform variables for all product variants. The configuration step plays a vital role in determining two important aspects of a product family: efficiency (cost savings due to commonality) and effectiveness (capability to satisfy performance requirements). Many existing product platform design methods ignore it, assuming a given platform configuration. Most approaches, whether or not they consider the configuration step, are single-platform methods, in which design variables are either shared across all product variants or not shared at all. In multiple-platform design, design variables may be shared among variants in any possible combination of subsets, offering opportunities for superior overall design but presenting a more difficult computational problem. In this work, sensitivity analysis and cluster analysis are used to improve both efficiency and effectiveness of a scale-based product family through multiple-platform product family design. Sensitivity analysis is performed on each design variable to help select candidate platform design variables and to provide guidance for cluster analysis. Cluster analysis, using performance loss due to commonization as the clustering criterion, is employed to determine platform configuration. An illustrative example is used to demonstrate the merits of the proposed method, and the results are compared with existing results from the literature.
Time-dependent lateral transmission of force in skeletal muscle

There is experimental evidence to suggest that extensible connective tissues are mechanically time-dependent. In view of this, the mechanics of time-dependent lateral stress transfer in skeletal muscle is investigated by employing a viscoelastic shear lag model for the transfer of tensile stress between muscle fibres and the surrounding extracellular matrix (ECM) by means of shear stresses at the interface between the muscle fibre and the ECM. The model allows for both mechanical strains in the muscle as well as the strain owing to muscle contraction. Both the ECM and the muscle fibre are modelled as viscoelastic solids. As a result, time-dependent lateral stress transfer can be studied under a variety of loading and muscle stimulation conditions. The results show that the larger the muscle fibre creep time relative to the ECM relaxation time, the longer it takes for the muscle fibre stress to relax. It also shows that the response of the muscle–ECM composite system also depends on the characteristic time of a strain history relative to the characteristic relaxation time of the ECM. The results from the present model provide significant insight into the role of the parameters that characterize the response of the muscle composite system.
Compensating Differentials for Sexual Harassment

Workplace sexual harassment is illegal, but many workers report that they have been sexually harassed. Exposure to the risk of sexual harassment may decrease productivity, which would reduce wages. Alternatively, workers may receive a compensating differential for exposure to sexual harassment, which would increase wages. Data on claims of sexual harassment filed with the Equal Employment Opportunity Commission are used to calculate the first measures of sexual harassment risks by industry, age group, and sex. Female workers face far higher sexual harassment risks. On balance, workers receive a compensating wage differential for exposure to the risk of sexual harassment.
Pregnancy and adoption among infertile women following ovulation induction and intrauterine insemination.

Using a retrospective cohort study, 214 clinically diagnosed infertile women who underwent ovulation induction and intrauterine insemination between 1991 and 1994 at a hospital-based centre of reproductive medicine, were followed up 5 years after treatment to assess their overall health, pregnancy and adoption status. Multivariate logistic regression analysis was used to estimate odds ratios and 95% confidence intervals for these outcomes, adjusted for age, education, infertility diagnosis, infertility status, parity, number of prior intrauterine insemination cycles, pregnancy following intrauterine insemination treatment, and undergoing other assisted reproductive procedures. Significant increased likelihood of pregnancy was observed for younger women, for women with secondary versus primary infertility, and for women who underwent other assisted reproductive procedures versus those who did not. Significant decreased likelihood of adoption was observed for women with a lower versus a higher educational l...
Regio- and stereoselective intramolecular Heck reactions of N-acyl-2,3-dihydro-4-pyridones

Abstract Intramolecular Heck reactions of N-acyl-2,3-dihydro-4-pyridones provide polycyclic heterocycles with high regio- and stereoselectivity.
Information-processing models of cognition

This article reviews recent progress in modeling human cognitive processes. Particular attention is paid to the use of computer programming languages as a formalism for modeling, and to computer simulation of the behavior of the systems modeled. Theories of human cognitive processes can be attempted at several levels: at the level of neural processes, at the level of elementary information processes (e.g., retrieval from memory, scanning down lists in memory, comparing simple symbols, etc.), or at the level of higher mental processes (e.g., problem solving, concept attainment). This article will not deal at all with neural models; it focuses mainly upon higher mental processes, but not without some attention to modeling the elementary processes and especially to the relationships between elementary and complex processes.
ROSAT/ASCA observations of the mixed-morphology supernova remnant W28

We present three sets of ROSAT PSPC and four sets of ASCA observations of the supernova remnant (SNR) W28. The overall shape of x-ray emission in W28 is elliptical, dominated by a centrally-concentrated interior emission, sharply peaked at the center. There are also partial northeastern and southwestern shells, and both central and shell x-ray emission is highly patchy.
Laser-driven polarized sources of hydrogen and deuterium

Abstract A novel laser-driven polarized source of hydrogen and deuterium which operates on the principle of spin exchange optical pumping is described. The advantages of this method over conventional polarized sources for internal target experiments are presented. Technological difficulties which prevent ideal source operation are outlined along with proposed solutions. At present, the laser-driven polarized hydrogen source delivers 8 × 10 16 atoms/s with a polarization (P z ) of 24%.
G-NetMon: A GPU-accelerated network performance monitoring system for large scale scientific collaborations

We have prototyped a GPU-accelerated network performance monitoring system, called G-NetMon, to support large-scale scientific collaborations at Fermilab. Our system exploits the data parallelism that exists within network flow data to provide fast analysis of bulk data movement between Fermilab and collaboration sites. Experiments demonstrate that our G-NetMon can rapidly detect sub-optimal bulk data movements.
Evolution and Fragmentation of Wide-Angle Wind Driven Molecular Outflows

We present two dimensional cylindrically symmetric hydrodynamic simulations and synthetic emission maps of a stellar wind propagating into an infalling, rotating environment. The resulting outflow morphology, collimation and stability observed in these simulations have relevance to the study of young stellar objects, Herbig-Haro jets and molecular outflows. Our code follows hydrogen gas with molecular, atomic and ionic components tracking the associated time dependent molecular chemistry and ionization dynamics with radiative cooling appropriate for a dense molecular gas. We present tests of the code as well as new simulations which indicate the presence of instabilities in the wind-blown bubble’s swept-up shell.
Chemoradiotherapy in squamous cell carcinoma of the anal canal: a single institution experience.

Purpose We reviewed the treatment outcomes and prognostic factors for patients with anal canal carcinoma who were treated with curative intent chemoradiotherapy (CRT) at Severance Hospital from 2005 to 2011.
What are the Building Blocks of Our Universe

We are living in a Golden Age of Astronomy. Cosmological Parameters are found with an unprecedented accuracy comparable to high energy physics. Yet, the known form of matter forms only a small fraction of the total energy density of the universe. Also, a mysterious dark energy dominates the universe and causes acceleration in the rate of expansion. These findings raise new questions concerning the ultimate constitution of matter in the universe.
In Defense of the Use of Commonsense Psychology in the Criminal Law

The criminal law depends upon 'commonsense' or 'folk' psychology, a seemingly innate theory used by all normal human beings as a means to understand and predict other humans' behavior. This paper discusses two major types of arguments that commonsense psychology is not a true theory of human behavior, and thus should be eliminated and replaced. The paper argues that eliminitivist projects fail to provide evidence that commonsense psychology is a false theory, and argues that there is no need to seek a replacement theory of behavior for use in the criminal law.
Determining the existence and nature of the quark-gluon plasma by Upsilon suppression at the LHC

Minijet production in √s = 5.5 TeV Pb + Pb collissions at the LHC is expected to produce a gluon-dominated plasma with large initial temperatures and energy densities. We discuss the implications of the high initial temperatures on the screening mass and on the relative suppression of members of the ϒ family. We demonstrate that pT dependence of the ϒ′/ϒ ratio is only expected if a quark-gluon plasma with significant energy density is present, and that the precise dependence of this ratio will strongly constrain the QGP models. We also propose that the PT spectra of the ϒ resonances themselves will provide valuable information by comparing these spectra to that of the Z boson, which should not be influenced by plasma production.
THE EFFECT OF REACTOR IRRADIATION UPON HYDROGEN ADSORPTION BY AN ALUMINA CATALYST

Abstract Hydrogen adsorption experiments were carried out on unirradiated and reactor-irradiated samples of gamma alumina (γ-Al 2 O 2 ) in an effort to interpret the known enhancement by radiation of the catalytic activity of this material. The specific surface area of 85 m 2 /g was not changed by irradiation, but the shapes of the hydrogen adsorption isotherms were altered. The observed monolayer capacity for hydrogen indicates that hydrogen atoms are adsorbed (at 78 °K) in one-to-one correspondence with the oxygen ions in the alumina surface. Nitrogen contamination, which is not removed by outgassing at 300 °C, has been detected. It is displaced systematically as hydrogen is adsorbed at 78 °K. Reactor irradiation appears to enhance this nitrogen release phenomenon.
Two-Dimensional Jet Mixing With a Pressure Gradient

An analytical study of nonsimilar jet mixing is made for compressible, nonisoenergetic flows. The conservation equations are solved for each of the streams above and below the dividing streamline by using Meksyn's asymptotic method of integration for solving boundary-layer problems. The problem of laminar mixing between two parallel streams is investigated for the case of a constant pressure gradient. It is found that the velocity and temperature profiles from the exact solution to the nonsimilar governing equations can be well approximated by the locally similar solution.
Some results in tree automata

The following three results concerning tree automata are presented in this paper. (1) Rounds has presented the following open problem: For every recognizable setR, can we construct a deterministic finite-state transformation recognizingR? We show that this is not possible, in fact, even for a local set. However, the following is true: For every recognizable setR there is an inverse projectionR′ effectively obtained such thatR′ is recognized by a deterministic finite-state transformation. (2) Martin and Vere in their study of tree automata leave open the question of whether Generalized Syntax Directed Transductions (GSDT's) are closed under Arden's transformation or Greibach's transformation, and conjecture that they are not. We prove that this conjecture is true. It is also shown that GSDT's are not closed under transformation to LR(k) grammars. (3) Peters and Ritchie have shown that if, in a grammar where the generative rules are context-free, there are “recognition” rules which are context-sensitive, the language recognized is still context-free. A tree-automata-oriented proof is given by Rounds. We show that a similar result holds also for right linear grammars, i.e., if the generative rules are right linear, then using context-sensitive rules for “recognition”, one can still recognize only regular languages. Some other related results concerning context-sensitive extensions of subclasses of context-free languages are also presented.
Fractal Structures in Adversarial Prediction

Fractals are self-similar recursive structures that have been used in modeling several real world processes. In this work we study how "fractal-like" processes arise in a prediction game where an adversary is generating a sequence of bits and an algorithm is trying to predict them. We will see that under a certain formalization of the predictive payoff for the algorithm it is most optimal for the adversary to produce a fractal-like sequence to minimize the algorithm's ability to predict. Indeed it has been suggested before that financial markets exhibit a fractal-like behavior [FP98, Man05]. We prove that a fractal-like distribution arises naturally out of an optimization from the adversary's perspective.In addition, we give optimal trade-offs between predictability and expected deviation (i.e. sum of bits) for our formalization of predictive payoff. This result is motivated by the observation that several time series data exhibit higher deviations than expected for a completely random walk.
A benchmark comparison of Monte Carlo particle transport algorithms for binary stochastic mixtures

Abstract We numerically investigate the accuracy of two Monte Carlo algorithms originally proposed by Zimmerman [1] and Zimmerman and Adams [2] for particle transport through binary stochastic mixtures. We assess the accuracy of these algorithms using a standard suite of planar geometry incident angular flux benchmark problems and a new suite of interior source benchmark problems. In addition to comparisons of the ensemble-averaged leakage values, we compare the ensemble-averaged material scalar flux distributions. Both Monte Carlo transport algorithms robustly produce physically realistic scalar flux distributions for the benchmark transport problems examined. The base Monte Carlo algorithm reproduces the standard Levermore–Pomraning model [3] , [4] results. The improved Monte Carlo algorithm generally produces significantly more accurate leakage values and also significantly more accurate material scalar flux distributions. We also present deterministic atomic mix solutions of the benchmark problems for comparison with the benchmark and the Monte Carlo solutions. Both Monte Carlo algorithms are generally significantly more accurate than the atomic mix approximation for the benchmark suites examined.
Integrability and fusion algebra for quantum mappings

We apply the fusion procedure to a quantum Yang-Baxter algebra associated with time-discrete integrable systems, notably integrable quantum mappings. We present a general construction of higher-order quantum invariants for these systems. As an important class of examples, we present the Yang-Baxter structure of the Gel'fand-Dikii mapping hierarchy that we have introduced in previous papers, together with the corresponding explicit commuting family of quantum invariants.
Functional rational expectations equilibria in market games

The rational expectations equilibrium (REE) has been criticized as an equilibrium concept in market game environments. Such an equilibrium may not exist generically, or it may introduce unrealistic assumptions about an economic agent’s knowledge or computational ability. We define an REE as a probability measure over uncertain states of nature which exploits all available information in a market game, and which exists for almost all economies. Furthermore, if retrading is allowed, it is possible for agents to compute such a ‘functional rational expectations equilibrium’ using straightforward numerical fixed point algorithms. The approach is demonstrated in a detailed numerical example.
Infrared emission from central dominant galaxies in X-ray luminous clusters

IRAS strip scans are used to study the emission properties of 27 dominant galaxies that lie in the center of clusters rich in hot gas. In this sample, 30 percent of the objects were detected at 12/25 microns, while 46 percent were detected at 60/100 microns. The ratio of the IR to optical flux densities is an order of magnitude greater than for elliptical and S0 galaxies. The presence of IR emission is not obviously correlated with z, m(v), Mv, the presence of young stellar populations, emission-line gas, the X-ray luminosity, or the cooling rate of hot gas.
The Higgs boson sector of the complex MSSM in the Feynman-diagrammatic approach

In the Minimal Supersymmetric Standard Model with complex parameters (cMSSM) we calculate higher order corrections to the Higgs boson sector in the Feynman-diagrammatic approach using the on-shell renormalization scheme. The application of this approach to the cMSSM, being complementary to existing approaches, is analyzed in detail. Numerical examples for the leading fermionic corrections, including the leading two-loop effects, are presented. Numerical agreement within 10% with other approaches is found for small and moderate mixing in the scalar top sector. The leading fermionic corrections, supplemented by the full logarithmic one-loop and the leading two-loop contributions are implemented into the public Fortran code FeynHiggsFastC.
Spontaneous reversal of vertical diplopia in Graves' eye disease

Two patients, among 77 examined in the past five years with Graves' eye disease and vertical diplopia, spontaneously resolved their vertical deviation. One had a maximum of 33 prism diopters of hypotropia decreasing to 1 prism diopter of hypophoria in 22 months, and the other a maximum of 12, improving to orthophoria in ten months. Ten mechanisms are considered. Five seem compatible with the findings of each of our two patients: reversal of a hormonal effect causing intracellular deposition of mucopolysaccharides, lengthening of the involved muscles from being chronically stretched, hypertrophy of the antagonist of the restricted muscle, resolution of abnormal co-contraction of the involved muscle when it was functioning as an antagonist, and reversal of fast calcium channel problems affecting muscle relaxation. No mechanism is proven to be the operating one. This report emphasizes the importance of delaying strabismus surgery in patients with Graves' eye disease until the motility findings are unchanged ...
Ultrarelativistic motion: Inertial and tidal effects in Fermi coordinates

Fermi coordinates are the natural generalization of inertial Cartesian coordinates to accelerated systems and gravitational fields. We study the motion of ultrarelativistic particles and light rays in Fermi coordinates and investigate inertial and tidal effects beyond the critical speed . In particular, we discuss the black-hole tidal acceleration mechanism for ultrarelativistic particles in connection with a possible origin for high-energy cosmic rays.
The Farahat–Higman ring of wreath products and Hilbert schemes

We study the structure constants of the class algebra RZ(Γn) of the wreath products Γn associated to an arbitrary finite group Γ with respect to the basis of conjugacy classes. We show that a suitable filtration on RZ(Γn) gives rise to the graded ring GΓ(n) with non-negative integer structure constants independent of n (some of which are computed), which are then encoded in a Farahat–Higman ring GΓ. The real conjugacy classes of Γ come to play a distinguished role and are treated in detail in the case when Γ is a subgroup of SL2(C). The above results provide new insight to the cohomology rings of Hilbert schemes of points on a quasi-projective surface X.
Stability of Roots of Polynomials Under Linear Combinations of Derivatives

Let T=α0I+α1D+⋅⋅⋅+αnDn, where D is the differentiation operator and \(\alpha_{0}\not=0\) , and let f be a square-free polynomial with large minimum root separation. We prove that the roots of Tf are close to the roots of f translated by −α1/α0.
Spectral inversion of an indefinite Sturm-Liouville problem due to Richardson

We study an indefinite Sturm?Liouville problem due to Richardson whose complicated eigenvalue dependence on a parameter has been a puzzle for decades. In atomic physics a process exists that inverts the usual Schr?dinger situation of an energy eigenvalue depending on a coupling parameter into the so-called Sturmian problem where the coupling parameter becomes the eigenvalue which then depends on the energy. We observe that the Richardson equation is of the Sturmian type. This means that the Richardson and its related Schr?dinger eigenvalue functions are inverses of each other and that the Richardson spectrum is therefore no longer a puzzle.
Focal points for DSS effectiveness

The primary emphasis in this presentation is to take a top-down view of a decision support system (DSS) and to see how the mere existence of DSS causes improvement in management effectiveness. The areas covered include development of information needs, requirement of consistency in using information, discipline in decision making, and the integration of decisions toward goals.The improved effectiveness from these areas is inherent in the information requirements that are set up during the development of a DSS. Can there be any doubt that improved information consistency and discipline in decision making improves management effectiveness? In other words, no matter the computational advantages and the efficiency of computers to manipulate and display numbers, a DSS automatically results in the identification of issues, begs for the resolution of those issues, and thus produces more consistent and integrated decisions in the choices of action plans and programs for the achievement of corporate goals.
Enantiopure enynyl sulfoxides via palladium-catalyzed coupling reactions

Abstract Enantiomerically pure 1-sulfinyl-1-en-3-ynes are prepared from 2-halovinylsulfoxides via Sonogashira or Stille coupling procedures. The trans -enynyl sulfoxides may be hydrogenated to provide (1 E , 3 Z )-dienylsulfoxides.
Observations of dislocation interactions with recrystallized grain boundaries

Abstract Possible evidence of the interaction of individual dislocations with recrystallized grain boundaries (GBs) was found in aluminum specimens that had been statically recrystallized after hot deformation. Matrix dislocations from the deformed material appeared to terminate on the recrystallized GB; however, GB dislocations (GBDs) that should have formed from the absorption of the matrix dislocations were not present. In addition, subboundary structure immediately in front of the moving GB appeared to have undergone accelerated dissociation. These observations suggest that rapid GB motion is not associated with lateral movement of GBDs, and short-range dislocation-GB interaction forces, probably image forces, could cause climb-induced vacancy supersaturations to form in front of the GB. This supersaturated vacancy atmosphere could constitute an important contribution to rapid GB migration.
Interaction of Spalled Particles with Shock Layer Flow

The influence of the solid particles injected into the shock layer by the spaliation of a carbonaceous ablating heatshield on the shock layer flow is investigated theoretically. The equation of motion of a solid particle is integrated using a polynomial expansion. Assuming a Gaussian distribution for the initial masses and velocities of the particles, the rates of production of CO, CN, C 3 , and turbulence energy are calculated by integrating those production rates for one particle over the mass and velocity distributions. The results for the environment of Stardust Earth reentry show that these production rates decay approximately exponentially in the normal direction from the ablating wall. Correlation formulas for the magnitudes and slopes of this decay pattern are derived. The lower limits of particle size and initial velocity are estimated for a carbon-phenolic material from a spectroscopic result obtained in an arcjet wind-tunnel test
Limited view Mach-Zehnder interferometric tomography for three-dimensional temperature reconstruction

Abstract The Mach-Zehnder interferometer is used in combination with axial tomography to obtain three-dimensional temperature measurements. Although axial tomography is well developed for when the two-dimensional projections of the field to be reconstructed are available in all directions, it is rather awkward when the viewing range of the projections is severely limited. It was demonstrated earlier, however, that when an initial guess of the reconstructed field is available, good quality reconstructions can be obtained. The purpose of this study is to demonstrate the usefulness of this technique with actual experimental data that contain noise. The case studied is that of an axisymmetric air jet, and the axial tomographic algorithm used is the algebraic reconstruction technique (ART) with some modifications.
Scattering at Planckian energies

Abstract We give a systematic analysis of forward scattering in (3+1)-dimensional quantum gravity, at center of mass energies comparable or larger than the Planck energy. We show that quantum gravitational effects in this kinematical regime are described by means of a topological field theory. We find that the scattering amplitudes display a universal behaviour similar to two-dimensional string amplitudes, thereby recovering results obtained previously by 't Hooft. Finally, we discuss the two-particle process in some detail.
Local Electronic Structure of a Single Magnetic Impurity in a Superconductor

We present the first three-dimensional, self-consistent calculation of the electronic structure near a strong classical magnetic impurity in a superconductor. Localized excited states are found within the energy gap which are half electron and half hole. The spatial structure of the positive-frequency (electronlike) spectral weight (or local density of states) can differ strongly from that of the negative frequency (holelike) spectral weight. The effect of the impurity on the continuum states above the energy gap is calculated with good spectral resolution for the first time. For sufficiently strong impurity potentials, the order parameter may change sign at the impurity site.
A Quasicontinuum study of nanovoid collapse under uniaxial loading in Ta

Abstract The mechanisms underlying the deformation of nanovoids in Ta single crystals are analyzed when they are subjected to cyclic uniaxial deformation using numerical simulations. Boundary and cell-size effects have been mitigated by means of the Quasicontinuum (QC) method. We have considered ≈1 billion-atom systems containing 10.9 nm voids. Two kinds of simulations have been performed, each characterized by a different boundary condition. First, we compress the material along the nominal [0 0 1] direction, resulting in a highly symmetric configuration that results in high stresses. Second, we load the material along the high-index [ 4 ¯ 8 19 ] direction to confine plasticity to a single slip system and break the symmetry. We find that the plastic response under these two conditions is strikingly different, the former governed by dislocation loop emission and dipole formation, while the latter is dominated by twinning. We calculate the irreversible plastic work budget derived from a loading–unloading cycle and identify the most relevant yield points. These calculations represent the first fully three-dimensional, fully non-local simulations of any body-centered cubic metal using QC.
Abort determination with non-adaptive neural networks for the Mars precision landers

Abstract The 2009 Mars Science Laboratory (MSL) will attempt the first precision landing on Mars using a modified version of the Apollo Earth entry guidance program. The guidance routine, Entry Terminal Point Controller (ETPC), commands the deployment of a supersonic parachute while converging the range to the landing target. For very dispersed cases, ETPC is unlikely to converge the range to the target and command parachute deployment within Mach number and dynamic pressure constraints. A full-lift-up abort can save 85% of these failed trajectories while abandoning the precision landing objective. In order to implement an abort, a failed trajectory needs to be recognized in real time. The application of artificial neural networks (ANNs) as an abort determination technique was evaluated. An ANN was designed, trained and tested using Monte Carlo simulations of MSL descent for a severe dust storm scenario. When incorporated into ETPC, the ANN correctly classifies 87% of descent trajectories as abort or non-abort, reducing the probability of losing MSL in a severe dust storm from 18% to 3.5%. This research shows that ANNs are capable of recognizing failed descent trajectories and can significantly increase the survivability of MSL for very dispersed cases.
Cluster Ellipticities as a Cosmological Probe

We investigate the dependence of the ellipticities of clusters of galaxies on cosmological parameters using large-scale cosmological simulations. We determine cluster ellipticities out to redshift unity for λCDM models with different mean densities Ωm and amplitudes of mass fluctuation σ8,0. The mean ellipticity increases monotonically with redshift for all models. Larger values of σ8,0, i.e., earlier cluster formation times, produce lower ellipticities. The dependence of ellipticity on Ωm is relatively weak in the range 0.2 ≤ Ωm ≤ 0.5 for high-mass clusters. The mean ellipticity (z) decreases linearly with the amplitude of mass fluctuations at the cluster redshift z, nearly independent of Ωm; on average, older clusters are more relaxed and are thus less elliptical. The distribution of ellipticities about the mean is approximated by a Gaussian, allowing a simple characterization of the evolution of ellipticity with redshift as a function of cosmological parameters. At z = 0, the mean ellipticity of high-mass clusters is approximated by (z = 0) = 0.245 - 0.070σ8,0 + 0.020Ωm,0. This relation opens up the possibility that, when compared with future observations of large cluster samples, the mean cluster ellipticity and its evolution could be used as a new, independent tool to constrain cosmological parameters, especially the amplitude of mass fluctuations, σ8,0.
Nobel Lecture: Bose-Einstein condensation in a dilute gas, the first 70 years and some recent experiments

Bose-Einstein condensation, or BEC, has a long and rich history dating from the early 1920s. In this article we will trace briefly over this history and some of the developments in physics that made possible our successful pursuit of BEC in a gas. We will then discuss what was involved in this quest. In this discussion we will go beyond the usual technical description to try and address certain questions that we now hear frequently, but are not covered in our past research papers. These are questions along the lines of: How did you get the idea and decide to pursue it? Did you know it was going to work? How long did it take you and why? We will review some our favorites from among the experiments we have carried out with BEC. There will then be a brief encore on why we are optimistic that BEC can be created with nearly any species of magnetically trappable atom. Throughout this article we will try to explain what makes BEC in a dilute gas so interesting, unique, and experimentally ${\mathrm{challenging}.}^{1}$
A survey of numerical solutions to the coagulation equation

We present the results of a systematic survey of numerical solutions to the coagulation equation for a rate coefficient of the form Aij (iμ jν + iν jμ) and monodisperse initial conditions. The results confirm that there are three classes of rate coefficients with qualitatively different solutions. For ν ≤ 1 and λ = μ + ν ≤ 1, the numerical solution evolves in an orderly fashion and tends towards a self-similar solution at large time t. The properties of the numerical solution in the scaling limit agree with the analytic predictions of van Dongen and Ernst. In particular, for the subset with μ > 0 and λ 1, the numerical solution tends towards a self-similar solution as t approaches a finite time t0. The mass spectrum nk develops at t0 a power-law tail nk k −τ at large masses that violates mass conservation, and runaway growth/gelation is expected to start at tcrit = t0 in the limit the initial number of particles n0 → ∞. The exponent τ is in general less than the analytic prediction (λ + 3)/2, and t0 = K / [(λ − 1)n0A11] with K = 1–2 if λ 1.1. For ν > 1, the behaviours of the numerical solution are similar to those found in a previous paper by us. They strongly suggest that there are no self-consistent solutions at any time and that runaway growth is instantaneous in the limit n0 → ∞. They also indicate that the time tcrit for the onset of runaway growth decreases slowly towards zero with increasing n0.
Decentralization, Hierarchies, and Incentives: A Mechanism Design Perspective

Separation of ownership from management, multidivisional firm organizations, delegation of production decisions to worker teams, delegation of pricing and advertising decisions to retail franchisers, reliance on intermediaries in trade or finance, and distribution of regulatory authority across different agencies represent examples of organizations that delegate and distribute decision-making authority instead of centralizing it. This paper reviews literature on costs and benefits of delegated decision making in hierarchical organizations or contracting networks with regard to problems of incentives and coordination. It starts by describing incentive and coordination costs of delegation in simple canonical examples of hierarchies where both information and incentives of different decisionmakers differ. One class of models pertain to contexts where the classical Revelation Principle applies, i.e., where costs of contractual complexity, information processing, or communication are absent, agents do not collude, and the mechanism designer can commit to the mechanism. Delegation may conceivably entail a loss of control and coordination arising from the divergence of information and incentives. Sufficient and necessary conditions for this loss to be mitigated entirely include risk neutrality, top-down contracting, and monitoring of transfers or production assignments between subordinates. The next class of models introduces communication costs that restrict the performance of centralized arrangements relative to delegation owing to a resulting loss of flexibility, which has to be traded off against possible control losses of delegation. Finally, consequences of collusion among agents is discussed, which typically enlarge the range of circumstances under which delegation can attain optimal second-best outcomes. The paper concludes with a discussion of the relevance of this theoretical literature to recently emerging empirical studies of industrial organizations where delegated decision making plays an important role: adoption of innovative human resource management practices, new information technologies and retail franchising.
Surrogate decision makers and proxy ownership: challenges of privacy management in health care decision making.

This study explored the communicative experiences of surrogates who served as decision makers for patients who were unable to convey health information and choices about treatment options. Drawing ...
Intermetallic compounds for high-temperature structural use.

The next generation of efficient turbines and engines will require materials that can withstand operating temperatures approaching 2000°C. Intermetallic compounds with high melting temperatures are candidates for this application, but the obstacle of their limited ductility must first be overcome. Because the available data on these materials is limited, a survey of the effects of chemistry and crystal structure must be performed. With the use of melting temperature and density as figures of merit, the most likely candidates have been identified for preliminary screening.
THE PERSISTENCE OF COOL GALACTIC WINDS IN HIGH STELLAR MASS GALAXIES BETWEEN z ~ 1.4 AND ~ 1

We present an analysis of the Mg II λλ2796, 2803 and Fe II λλ2586, 2600 absorption line profiles in co-added spectra of 468 galaxies at 0.7 10 M ☉ yr–1 host strong outflows in both this and the W09 sample, we do not detect outflows in lower-SFR (i.e., log M */M ☉ 10.5) galaxies at lower redshifts. Using a simple galaxy evolution model that assumes exponentially declining SFRs, we infer that strong outflows persist in galaxies with log M */M ☉ > 10.5 as they age between z = 1.4 and z ~ 1, presumably because of their high absolute SFRs. Finally, our spectral analysis, combined with high-resolution Hubble Space Telescope/Advanced Camera for Surveys imaging, weakly suggests that outflow absorption strength increases with galaxy SFR surface density.
Super Silyl Stereo-Directing Groups for Complete 1,5-Syn and -Anti Stereoselectivities in the Aldol Reactions of β-Siloxy Methyl Ketones with Aldehydes

In this communication, we report that substrate-controlled 1,5-syn and -anti stereoinduction in the aldol reaction of β-tris(trialkylsilyl)siloxy methyl ketones can be achieved with high diastereoselectivities. Tris(trialkylsilyl)silyl groups are easily prepared and play an important role in the selectivities of these reactions. Furthermore, all of the 1,3,5-triol stereoisomers can easily be prepared from β-siloxy methyl ketones in no more than three steps.
Synthesis of 2‐amino‐6,7‐dihydrothieno‐[3′,2′:5,6]pyrido[2,3‐d]pyrimidin‐4‐one

2-Amino-6,7-dihydrothieno[3′,2′:5,6]pyrido[2,3-rf]pyrimidin-4-one (1) was prepared in three steps from S-(3-butynyl)thiosemicarbazide hydroiodide (3) and diethyl ketomalonate. The featured step in this synthetic sequence was an intramolecular Diels-Alder reaction of the in situ generated 3-(3-butynylthio)-6-carboethoxy-5-chloro-1,2,4-triazine (9) to provide the key intermediate 5-carboethoxy-6-chloro-2,3-dihydrothieno-[2,3-b]pyridine (6). In the course of studies directed toward the preparation of 1, thermolysis of 3-(3-butynyl-thio)-6-carboethoxy-1,2,4-triazin-5(2H)-one (2) was found to involve competitive intramolecular Diels-Alder and intramolecular coplanar cycloamination processes, providing the 2,3-dihydrothieno[2,3-b]pyridin-6(7H)-one (4) and the 1,3-thiazino[3,2-b]-1,2,4-triazin-3-one (5) derivatives, respectively.
The Performance Effects of Modular Production in the Apparel Industry

This article identifies and explains differences in performance between two widely used alternative work methods-module and bundle production—in the basics sector of the apparel industry. This research is based on interviews with managers and surveys of worker attitudes and perceptions. We find that a team production system in the apparel industry, called modules, performs better than the traditional bundle system on such measures as quality, costs, and responsiveness to retailers. Modules also perform better than bundles in reducing work-in-process inventory and throughput time. We argue that performance improvements are realized through coordination among the team members as a result of their ability to self-regulate work, eliminate bottlenecks, resolve conflicts, help one another solve problems, and make improvements in the production process.
ON THE FEEDBACK CONTROL OF THE WAVE EQUATION

Abstract This paper addresses the problem of design of collocated and non-collocated controllers for a uniform bar without structural damping. The bar whose dynamics are described by the wave equation is required to perform a rest-to-rest maneuver. A time delay controller whose gains are determined using the root-locus technique is used to control the non-collocated system. The effect of sensor locations on the stability of the system is investigated when the actuator is located at the one end of the bar. The critical gains which correspond to a pair of poles entering the right-half of the s -plane and the optimal gains corresponding to locating the closed-loop poles at the left extreme of the root-locus for each vibration mode are determined. The gain which minimizes a quadratic cost, in the range of the critical gains, is selected as the optimum gain.