cssi/SciSciGPT-SciSciNet huggingface dataset:
Primality Proving via One Round in ECPP and One Iteration in AKS

In August 2002, Agrawal, Kayal and Saxena announced the first deterministic and polynomial-time primality-testing algorithm. For an input n, the Agarwal-Kayal-Saxena (AKS) algorithm runs in time $\tilde{O}(\log^{7.5} n)$ (heuristic time $\tilde{O}(\log^6 n)$). Verification takes roughly the same amount of time. On the other hand, the Elliptic Curve Primality Proving algorithm (ECPP) runs in random heuristic time $\tilde{O}(\log^{6} n)$ (some variant has heuristic time complexity $\tilde{O}(\log^4 n)$) and generates certificates which can be easily verified. However, it is hard to analyze the provable time complexity of ECPP even for a small portion of primes. More recently, Berrizbeitia gave a variant of the AKS algorithm, in which some primes (of density $O({ 1 / {\log}^2\,n })$) cost much less time to prove than a general prime does. Building on these celebrated results, this paper explores the possibility of designing a randomized primality-proving algorithm based on the AKS algorithm. We first generalize Berrizbeitia's algorithm to one which has higher density ($\Omega( {1/{\log}\log n })$) of primes whose primality can be proved in time complexity $\tilde{O}(\log^{4} n)$. For a general prime, one round of ECPP is deployed to reduce its primality proof to the proof of a random easily proved prime, thus we achieve heuristic time complexity $\tilde{O}(\log^{4} n)$ for all primes.
Corporate entrepreneurship strategy: extending the integrative framework through the lens of complexity science

Whereas our understanding of corporate entrepreneurship (CE) and corporate entrepreneurship strategy (CES) continues to expand, there has been little theoretical development to support the most extensive framework to date: the integrative model of CES as proposed by Ireland et al. (Entrep Theory Pract 33(1):19–46, 2009). According to the model, CES is built upon the “three foundational elements of an entrepreneurial strategic vision, a pro-entrepreneurship organizational architecture, and entrepreneurial processes and behaviors as exhibited throughout the organization” (Ireland et al. 2009, p. 38). The purpose of this study is to present a broad, overarching theory—complexity science—to examine the key elements and propositions of the CES model. Complexity science—founded on assumptions of interdependent heterogeneous agents and nonlinear interactions, as well as non-deterministic and potentially extreme outcomes—offers established multi-level concepts, theoretical boundary conditions, and methodological guidance for scholars to build and test future studies on CE and CES. Though our complexity perspective draws extensively from conceptual work on complex adaptive systems and agent-based models, we ground our arguments on the empirical ubiquity of power law distributions in all constructs and levels of analysis within the CES model. We conclude with a detailed research agenda, as well as a prescriptive discussion related to theory development, quantitative analysis, and practical applications to guide future studies on CE.
Effective field theory for highly ionized plasmas

Abstract We examine the equilibrium properties of hot, non-relativistic plasmas. The partition function and density correlation functions of a plasma with several species are expressed in terms of a functional integral over electrostatic potential distributions. This is a convenient formulation for performing a perturbative expansion. The theory is made well-defined at every stage by employing dimensional regularization which, among other virtues, automatically removes the unphysical (infinite) Coulomb self-energy contributions. The leading order, field-theoretic tree approximation automatically includes the effects of Debye screening. No further partial resummations are needed for this effect. Subleading, one-loop corrections are easily evaluated. The two-loop corrections, however, have ultraviolet divergences. These correspond to the short-distance, logarithmic divergence which is encountered in the spatial integral of the Boltzmann exponential when it is expanded to third order in the Coulomb potential. Such divergences do not appear in the underlying quantum theory – they are rendered finite by quantum fluctuations. We show how such divergences may be removed and the correct finite theory obtained by introducing additional local interactions in the manner of modern effective quantum field theories. We compute the two-loop induced coupling by exploiting a non-compact su(1, 1) symmetry of the hydrogen atom. This enables us to obtain explicit results for density–density correlation functions through two-loop order and thermodynamic quantities through three-loop order. The induced couplings are shown to obey renormalization group equations, and these equations are used to characterize all leading logarithmic contributions in the theory. A linear combination of pressure plus energy and number densities is shown to be described by a field-theoretic anomaly. The effective Lagrangian method that we employ yields a simple demonstration that, at long distance, correlation functions have an algebraic fall off (because of quantum effects) rather than the exponential damping of classical Debye screening. We use the effective theory to compute, easily and explicitly, this leading long-distance behavior of density correlation functions. The presentation is pedagogical and self-contained. The results for thermodynamic quantities at three-loop [or O(n5/2)] order, and for the leading long-distance forms of correlation functions, agree with previous results in the literature, but they are obtained in a novel and simple fashion using the effective field theory. In addition to the new construction of the effective field theory for plasma physics, we believe that the results we report for the explicit form of correlation functions at two-loop order, as well as the determination of higher-order leading-logarithmic contributions, are also original.
Effect of Cell and Microvillus Mechanics on the Transmission of Applied Loads to Single Bonds in Dynamic Force Spectroscopy

Receptor-ligand interactions that mediate cellular adhesion are often subjected to forces that regulate their detachment via modulating off-rates. Although the dynamics of detachment is primarily controlled by the physical chemistry of adhesion molecules, cellular features such as cell deformability and microvillus viscoelasticity have been shown to affect the rolling velocity of leukocytes in vitro through experiments and simulation. In this work, we demonstrate via various micromechanical models of two cells adhered by a single (intramolecular) bond that cellular viscoelasticity resulting from the interplay of cellular deformation and hydrodynamic drag modulates transmission of an applied external load to an intramolecular bond, and thus the dynamics of detachment. Specifically, it is demonstrated that the intermolecular bond force is not equivalent to the instantaneous applied force and that the instantaneous bond force decreases with increasing cellular viscoelasticity. As cellular compliance increases, not only does the time lag between the applied load and the bond force increase, an initial response time is observed during which cell deformation is observed without transfer of force to the bond. It is further demonstrated that following tether formation the instantaneous intramolecular bond force increases linearly at a rate dependent on microvillus viscosity. Monte Carlo simulations with fixed kinetic parameters predict that both cell and microvillus compliance increase the average rupture time, although the average rupture force based on bond length remains nearly unchanged.
Exponentially tapered H-tree clock distribution networks

Exponentially tapered interconnect can reduce the dynamic power dissipation of clock distribution networks. A criterion for sizing H-tree clock networks is proposed. The technique reduces the power dissipated for an example clock network by up to 15% while preserving the signal transition times and propagation delays. Furthermore, the inductive behavior of the interconnects is reduced, decreasing the inductive noise. Exponentially tapered interconnects decrease by approximately 35% the difference between the overshoots in the signal at the input of a tree. As compared to a uniform tree with the same area overhead, overshoots in the signal waveform at the source of the tree are reduced by 40%.
Reheating of the Universe and Population III

We note that current observational evidence strongly favors a conventional recombination of ionized matter subsequent to redshift z = 1200, followed by reionization prior to redshift z = 5 and compute how this would have occurred in a standard scenario for the growth of structure. Extending prior semianalytic work, we show by direct, high-resolution numerical simulations (of a COBE normalized CDM + Λ model) that reheating will occur in the interval 20 > z > 7, followed by reionization and accompanied by a significant increase in the Jeans mass. However, the evolution of the Jeans mass does not significantly affect star formation in dense, self-shielded clumps of gas, which are detached from the thermal evolution of the rest of the universe. On average, the growth of the Jeans mass tracks the growth of the nonlinear mass scale, a result we suspect is due to nonlinear feedback effects. Cooling on molecular hydrogen leads to a burst of star formation prior to reheating, which produces Population III stars with Ω* reaching 10-5.5 and /Z☉ reaching 10-3.7 by z ~ 14. Star formation subsequently slows down as molecular hydrogen is depleted by photodestruction and the rise of the temperature. At later times, z < 10, when the characteristic virial temperature of gas clumps reach 104 degrees, star formation increases again as hydrogen line cooling become efficient. Objects containing Population III stars accrete mass with time and, as soon as they reach 104 K virial temperature, engage in renewed star formation and turn into normal Population II objects having an old Population III metal-poor component.
Electronic automotive clocks

Electronic clocks are rapidly becoming practical for automotive applications. These digital clocks promise not only superior timekeeping in automotive clocks, but they also could be used for a myriad of timing functions throughout the car. These range from turn signal flashers to top-speed limiting and safety-monitoring checks. Integrated circuits utilizing complementary metal oxide semiconductor devices (CMOS and silicon gate CMOS) make several system approaches feasible. This paper outlines some possible system approaches and summarizes considerations for CMOS IC's, quartz crystals, and electronic readout devices.
Modal reduction of mathematical models of biological molecules

This paper reports a detailed study of modal reduction based on either linear normal mode (LNM) analysis or proper orthogonal decomposition (POD) for modeling a single @a-d-glucopyranose monomer as well as a chain of monomers attached to a moving atomic force microscope (AFM) under harmonic excitations. Also a modal reduction method combining POD and component modal synthesis is developed. The accuracy and efficiency of these methods are reported. The focus of this study is to determine to what extent these methods can reduce the time and cost of molecular modeling and simultaneously provide the required accuracy. It has been demonstrated that a linear reduced order model is valid for small amplitude excitation and low frequency excitation. It is found that a nonlinear reduced order model based on POD modes provides a good approximation even for large excitation while the nonlinear reduced order model using linear eigenmodes as the basis vectors is less effective for modeling molecules with a strong nonlinearity. The reduced order model based on component modal synthesis using POD modes for each component also gives a good approximation. With the reduction in the dimension of the system using these methods the computational time and cost can be reduced significantly.
How many kinds of reasoning? Inference, probability, and natural language semantics

Abstract The “new paradigm” unifying deductive and inductive reasoning in a Bayesian framework (Oaksford & Chater, 2007; Over, 2009 ) has been claimed to be falsified by results which show sharp differences between reasoning about necessity vs. plausibility (Heit & Rotello, 2010; Rips, 2001; Rotello & Heit, 2009). We provide a probabilistic model of reasoning with modal expressions such as “necessary” and “plausible” informed by recent work in formal semantics of natural language, and show that it predicts the possibility of non-linear response patterns which have been claimed to be problematic. Our model also makes a strong monotonicity prediction, while two-dimensional theories predict the possibility of reversals in argument strength depending on the modal word chosen. Predictions were tested using a novel experimental paradigm that replicates the previously-reported response patterns with a minimal manipulation, changing only one word of the stimulus between conditions. We found a spectrum of reasoning “modes” corresponding to different modal words, and strong support for our model’s monotonicity prediction. This indicates that probabilistic approaches to reasoning can account in a clear and parsimonious way for data previously argued to falsify them, as well as new, more fine-grained, data. It also illustrates the importance of careful attention to the semantics of language employed in reasoning experiments.
Magnetic Flares on Asymptotic Giant Branch Stars

We investigate the consequences of magnetic flares on the surface of asymptotic giant branch (AGB) and similar stars. In contrast to the solar wind, in the winds of AGB stars the gas cooling time is much shorter than the outflow time. As a result, we predict that energetic flaring will not inhibit, and may even enhance, dust formation around AGB stars. If magnetic flares do occur around such stars, we expect some AGB stars to exhibit X-ray emission; indeed, certain systems including AGB stars, such as Mira, have been detected in X-rays. However, in these cases, it is difficult to distinguish between potential AGB star X-ray emission and, e.g., X-ray emission from the vicinity of a binary companion. Analysis of an archival ROSAT X-ray spectrum of the Mira system suggests an intrinsic X-ray luminosity ~2 × 1029 ergs s-1 and temperature ~107 K. These modeling results suggest that magnetic activity, either on the AGB star (Mira A) or on its nearby companion (Mira B), is the source of the X-rays, but do not rule out the possibility that the X-rays are generated by an accretion disk around Mira B.
The Abundance of Interstellar Boron

We use new Space Telescope Imaging Spectrograph (STIS) and archival Goddard High Resolution Spectrograph (GHRS) observations to study interstellar B II λ1362 and O I λ1355 absorption along seven sight lines. Our new column density measurements, combined with measurements of four sight lines from the literature, allow us to study the relative B/O abundances over a wide range of interstellar environments. We measure sight-line-integrated relative gas-phase abundances in the range [B/O] = -1.00 to -0.17, and our data show that the B/O abundances are anticorrelated with average sight line densities over the range lognH ≈ -1.3 to +0.7. Detailed comparisons of the B II and O I line shapes show that the B/O ratio is significantly higher in warm interstellar clouds than in cool clouds. These results are consistent with the incorporation of boron into dust grains in the diffuse ISM. Since boron is likely incorporated into grains, we derive a lower limit to the present-day total (gas + dust) interstellar boron abundance of B/H (2.5 ± 0.9) × 10-10. The effects of dust depletion and ionization differences from element to element will make it very difficult to reliably determine 11B/10B along most interstellar sight lines.
Exploring the correlations between globular cluster populations and supermassive black holes in giant galaxies

This paper presents an analysis of the correlation between the number of globular clusters (N GC) in giant galaxies and the mass of the galaxies' central supermassive black hole (M SMBH). I construct a sample of 20 elliptical, spiral, and S0 galaxies with known SMBH masses and with accurately measured GC system properties derived from wide-field imaging studies. The coefficients of the best-fitting N GC-M SMBH relation for the early-type galaxies are consistent with those from previous work but in some cases have smaller relative errors. I examine the correlation between N GC and M SMBH for various subsamples and find that elliptical galaxies show the strongest correlation, while S0 and pseudobulge galaxies exhibit increased scatter. I also compare the quality of the fit of the numbers of metal-poor GCs versus SMBH mass and the corresponding fit for metal-rich GCs. I supplement the 20 galaxy sample with 10 additional galaxies with reliable N GC determinations but without measured M SMBH. I use this larger sample to investigate correlations between N GC and host galaxy properties like total galaxy luminosity and stellar mass, and bulge luminosity and mass. I find that the tightest correlation is between N GC and total galaxy stellar mass. This lends support to the notion that N GC and M SMBH are not directly linked but are correlated because both quantities depend on the host galaxy potential. Finally, I use the N GC-M SMBH relation derived from the 20 galaxy sample to calculate predicted M SMBH values for the 10 galaxies with accurate N GC measurements but without measured SMBH masses.
AN APPLICATION OF MULTILEVEL MODEL PREDICTION TO NELS:88

Multilevel modeling is often used in the social sciences for analyzing data that has a hierarchical structure, e.g., students nested within schools. In an earlier study, we investigated the performance of various prediction rules for predicting a future observable within a hierarchical data set (Afshartous & de Leeuw, 2004). We apply the multilevel prediction approach to the NELS:88 educational data in order to assess the predictive performance on a real data set; four candidate models are considered and predictions are evaluated via both cross-validation and bootstrapping methods. The goal is to develop model selection criteria that assess the predictive ability of candidate multilevel models. We also introduce two plots that 1) aid in visualizing the amount to which the multilevel model predictions are “shrunk” or translated from the OLS predictions, and 2) help identify if certain groups exist for which the predictions are particularly good or bad.
Integrated identification and robust control

Abstract A framework for integrated identification and control is presented. As part of this framework, frequency domain uncertainty bounds are derived for robust stability tests, a robust stability test for elliptical bounds is developed for SISO systems, a methodology for estimating controller performance is derived, and an optimal experiment design methodology for control-relevant identification is outlined. An example is presented to illustrate how the tools of the framework fit together.
Hydrodynamic and magnetohydrodynamic computations inside a rotating sphere

Numerical solutions of the incompressible magnetohydrodynamic (MHD) equations are reported for the interior of a rotating, perfectly-conducting, rigid spherical shell that is insulator-coated on the inside. A previously-reported spectral method is used which relies on a Galerkin expansion in Chandrasekhar?Kendall vector eigenfunctions of the curl. The new ingredient in this set of computations is the rigid rotation of the sphere. After a few purely hydrodynamic examples are sampled (spin down, Ekman pumping, inertial waves), attention is focused on selective decay and the MHD dynamo problem. In dynamo runs, prescribed mechanical forcing excites a persistent velocity field, usually turbulent at modest Reynolds numbers, which in turn amplifies a small seed magnetic field that is introduced. A wide variety of dynamo activity is observed, all at unit magnetic Prandtl number. The code lacks the resolution to probe high Reynolds numbers, but nevertheless interesting dynamo regimes turn out to be plentiful in those parts of parameter space in which the code is accurate. The key control parameters seem to be mechanical and magnetic Reynolds numbers, the Rossby and Ekman numbers (which in our computations are varied mostly by varying the rate of rotation of the sphere) and the amount of mechanical helicity injected. Magnetic energy levels and magnetic dipole behaviour are exhibited which fluctuate strongly on a timescale of a few eddy turnover times. These seem to stabilize as the rotation rate is increased until the limit of the code resolution is reached.
The Spin-Statistics Theorem in Arbitrary Dimensions

We investigate the spin-statistics connection in arbitrary dimensions for hermitian spinor or tensor quantum fields with a rotationally invariant bilinear Lagrangian density. We use essentially the same simple method as for space dimension D=3. We find the usual connection (tensors as bosons and spinors as fermions) for D=8n+3,8n+4,8n+5, but only bosons for spinors and tensors in dimensions 8n±1 and 8n. In dimensions 4n+2 the spinors may be chosen as bosons or fermions.
Inventor moral hazard in university licensing: The role of contracts

Abstract We examine commonly observed forms of payment, such as milestones, royalties, or consulting contracts as ways of engaging inventors in the development of licensed inventions. Our theoretical model shows that when milestones are feasible, royalties are not optimal unless the licensing firm is risk averse. The model also predicts the use of consulting contracts which improve the firm’s ability to monitor inventor effort. Because these contracts increase the firm’s expected profits, the upfront fee that the university can charge is higher than otherwise. These results therefore support the commonly observed university policy of allowing faculty to consult with licensing firms outside of their university contracts. They also support firm policies of including milestones. An empirical analysis based on a survey of 112 businesses that license-in university inventions supports the complementarity of milestones and consulting suggested by the theory.
Non-Gaussian features of primordial fluctuations in single field inflationary models

We compute the three point correlation functions for primordial scalar and tensor fluctuations in single field inflationary models. We obtain explicit expressions in the slow roll limit where the answer is given terms of the two usual slow roll parameters. In a particular limit the three point functions are determined completely by the tilt of the spectrum of the two point functions. We also make some remarks on the relation of this computation to dS/CFT and AdS/CFT. We emphasize that (A)dS/CFT can be viewed as a statement about the wavefunction of the universe.
Temperature inversions, thermal tides, and water ice clouds in the Martian tropics

[1] We report new results on the structure and dynamics of the tropical atmosphere of Mars derived from a combination of radio occultation measurements by Mars Global Surveyor and simulations by a Mars general circulation model (MGCM). Radio occultation experiments sounded the equatorial atmosphere at latitudes of 36°N to 30°S during midsummer of the Northern Hemisphere (Ls = 134°–162°), sampling the predawn thermal structure at a local time of ∼0412. Elevated temperature inversions are a conspicuous feature of these observations. They appear at pressures between 30 and 200 Pa, well above the surface, and their magnitude exceeds 6 K in 34% of the temperature profiles in this latitude band. The properties and spatial distribution of these elevated inversions are organized across the tropics on planetary scales. Inversions are strongest and occur most frequently above elevated terrain, achieving a peak magnitude of ∼30 K near Tharsis, and their altitude generally increases toward the south. According to MGCM simulations, which closely resemble the observations, these temperature inversions arise from zonally modulated thermal tides. The best simulation includes an interactive hydrologic cycle, which results in strong coupling between the thermal tides and radiatively active water ice clouds. Prominent clouds form in response to wave-induced adiabatic cooling and evolve in a pattern closely correlated with the thermal structure of the tides. The tides in turn are intensified by radiative forcing from the clouds. This tide-cloud coupling imposes strong diurnal modulation on the properties of clouds in the tropics.
Report on Forum 2000: Fluid Properties for New Technologies -- Connecting Virtual Design With Physical Reality

Forum 2000 was held at the 14th Symposium for Thermophysical Properties, with all symposium attendees invited. The forum addressed the present needs and priorities for thermophysical properties measurements and the challenges facing the experimental community. Seven distinguished panelists presented brief overviews of issues related to a wide variety of subjects, and three discussion periods were held. Topics included whether simulation can replace experiment, properties needs for new miniaturization techniques, real problems such as nuclear waste cleanup, data needs for electrolyte systems and new generations of electric power plants, and data needs for unconventional materials such as molten metals and soft solids.
Testing the mean of an asymmetric population: Johnson's modified t test revisited

Confidence intervals for the mean of an asymmetric distribution can be based on Student's t statistic or on Johnson's modified t statistic; Johnson's statistic has two variants, based on a linear and a quadratic approximation respectively. The quadratic approximation is complicated and is first investigated geometrically, which results in new insight. Next Monte Carlo experiments yield estimates of the coverage and power of several variations on Johnson's test. These experiments show that the quadratic approximation is superior.
Simple robust stability tests for polynomials with real parameter uncertainty

In this paper we consider several problems related to the robust stability of polynomials whose coefficients depend on real parameters. We first show that if these parameters appear linearly in the coefficients, the computation of the largest stability hypercube with a fixed centre does not require a frequency ‘sweep’. Its size can be determined by considering a finite set of frequencies. We also demonstrate that for some polynomials where the coefficients themselves are polynomials in the parameters, the determination of stability can be made in a manner that involves a single frequency sweep and where at each frequency a finite number of simple tests are carried out. The methods are based on the Nyquist theorem and ‘value set’ ideas, and the approach provides analytical solutions.
Testing Bayes Rule and the Representativeness Heuristic: Some Experimental Evidence

The psychological literature has identified a number of heuristics which individuals may use in making judgements or choices under uncertainty. Mathematically equivalent problems may be treated differently depending upon details of the decision setting. The results presented in this paper are consistent with those findings. In equivalent problems subjects appear to adopt different strategies in response to observing different data. Some experiments included financial incentives for accuracy and some did not. The majority of subjects in both treatments behaved reasonably, but of those lacking financial incentives a larger proportion gave absurd responses. This suggests that data from decision experiments in which no financial incentives were should be treated as possibly contaminated and statistical methods robust against outliers employed.
A Quantum Mechanical Relation Connecting Time, Temperature, and Cosmological Constant of the Universe: Gamow'S Relation Revisited as a Special Case

Considering our expanding universe as made up of gravitationally interacting particles which describe particles of luminous matter, dark matter and dark energy which is represented by a repulsive harmonic potential among the points in the flat 3-space and incorporating Mach’s principle into our theory, we derive a quantum mechanical relation connecting, temperature of the cosmic microwave background radiation, age, and cosmological constant of the universe. When the cosmological constant is zero, we get back Gamow’s relation with a much better coefficient. Otherwise, our theory predicts a value of the cosmological constant 2.0×10−56 cm−2 when the present values of cosmic microwave background temperature of 2.728 K and age of the universe 14 billion years are taken as input.
Freeform Skeletal Shape Optimization of Compliant Mechanisms

Compliant mechanisms are elastic continua used to transmit or transform force and motion mechanically. The topology optimization methods developed for compliant mechanisms also give the shape for a chosen parameterization of the design domain with a fixed mesh. However, in these methods, the shapes of the flexible segments in the resulting optimal solutions are restricted either by the type or the resolution of the design parameterization. This limitation is overcome in this paper by focusing on optimizing the skeletal shape of the compliant segments in a given topology. It is accomplished by identifying such segments in the topology and representing them using Bezier curves. The vertices of the Bezier control polygon are used to parameterize the shape-design space. Uniform parameter steps of the Bezier curves naturally enable adaptive finite element discretization of the segments as their shapes change. Practical constraints such as avoiding intersections with other segments, self-intersections, and restrictions on the available space and material, are incorporated into the formulation. A multi-criteria function from our prior work is used as the objective. Analytical sensitivity analysis for the objective and constraints is presented and is used in the numerical optimization. Examples are included to illustrate the shape optimization method.
Copper-Catalyzed Hydroalkylation of Terminal Alkynes

We have developed a copper-catalyzed hydroalkylation of terminal alkynes using alkyl triflates as coupling partners and (Me2HSi)2O as a hydride donor. The hydroalkylation proceeds with excellent anti-Markovnikov regioselectivity and provides exclusively (E)-alkenes. We have demonstrated that both alkyl- and aryl-substituted alkynes can be used as substrates, together with 1° alkyl and benzylic triflates. Finally, the transformation can be accomplished in the presence of a wide range of functional groups. Overall, the new hydroalkylation reaction allows highly efficient and diastereospecific synthesis of (E)-alkenes from readily available terminal alkynes and alkyl triflates. On the basis of a preliminary mechanistic study, we propose that the hydroalkylation reaction involves copper hydride formation, hydrocupration of an alkyne, and alkylation of an alkenyl copper intermediate.
Numerical studies of differential equations related to theoretical financial markets

Abstract Numerical computations are performed on a model which has been proposed to describe the characteristic and psychological aspects of financial markets in a pure setting. Overreactions, fluctuations, and convergence to realistic values are observed in these calculations. By varying parameters related to either emotional or rational motivations, one can obtain the spectrum of patterns which range from efficient to chaotic markets.
A DES Procedure Applied to a Wall-Mounted Hump

This paper describes a detached-eddy simulation(DES) for the flow over a wall mounted hump using MBFLO3 1,2 . The Reynolds number based on the hump chord is Rec = 9.36◊10 5 with an inlet Mach number of 0.1. Solutions of the three-dimensional Reynolds-averaged NavierStokes(RANS) procedure are obtained using the Wilcox k ! equations. The DES results are obtained using the model presented by Bush and Mani 3 and are compared with RANS solutions and experimental data from NASA’s 2004 Computational Fluid Dynamics Validation on Synthetic Jets and Turbulent Separation Control Workshop 4,5 . The DES procedure exhibited a three-dimensional flow structure in the wake, with a 13.65% shorter mean separation region compared to RANS and a mean reattachment length that is in good agreement with experimental measurements. DES predictions of the pressure coecient in the separation region also exhibit good agreement with experiment and are more accurate than RANS predictions.
Flag arrangements and triangulations of products of simplices

Abstract We investigate the line arrangement that results from intersecting d complete flags in C n . We give a combinatorial description of the matroid T n , d that keeps track of the linear dependence relations among these lines. We prove that the bases of the matroid T n , 3 characterize the triangles with holes which can be tiled with unit rhombi. More generally, we provide evidence for a conjectural connection between the matroid T n , d , the triangulations of the product of simplices Δ n − 1 × Δ d − 1 , and the arrangements of d tropical hyperplanes in tropical ( n − 1 ) -space. Our work provides a simple and effective criterion to ensure the vanishing of many Schubert structure constants in the flag manifold, and a new perspective on Billey and Vakil's method for computing the non-vanishing ones.
Plasma synthesis of single-crystal silicon nanoparticles for novel electronic device applications

Single-crystal nanoparticles of silicon, several tens of nanometres in diameter, may be suitable as building blocks for single-nanoparticle electronic devices. Previous studies of nanoparticles produced in low-pressure plasmas have demonstrated the synthesis of nanocrystals 2–10 nm diameter but larger particles were amorphous or polycrystalline. This work reports the use of a constricted, filamentary capacitively coupled low-pressure plasma to produce single-crystal silicon nanoparticles with diameters between 20 and 80 nm. Particles are highly oriented with predominantly cubic shape. The particle size distribution is rather monodisperse. Electron microscopy studies confirm that the nanoparticles are highly oriented diamond-cubic silicon.
Theories of non-Fermi liquid behavior in heavy fermions

Abstract I will review our incomplete understanding of non-Fermi liquid behavior in heavy fermion systems at a quantum critical point. General considerations suggest that critical antiferromagnetic fluctuations do not destroy the Fermi surface by scattering the heavy electrons, but by actually breaking up the internal structure of the heavy fermion. I contrast the weak, and strong-coupling view of the quantum phase transition, emphasizing puzzles and questions that recent experiments raise.
Recent advances in stimuli-responsive degradable block copolymer micelles: synthesis and controlled drug delivery applications

(Bio)degradation in response to external stimuli (stimuli-responsive degradation, SRD) is a desired property in constructing novel nanostructured materials. For polymer-based multifunctional drug delivery applications, the degradation enables fast and controlled release of encapsulated therapeutic drugs from delivery vehicles in targeted cells. It also ensures the clearance of the empty device after drugs are delivered to the body. This review summarizes recent development of various strategies to the design and synthesis of self-assembled micellar aggregates based on novel amphiphilic block copolymers having different numbers of stimuli-responsive cleavable elements at various locations. These cleavable linkages including disulfide, acid-labile, and photo-cleavable linkages are incorporated into micelles, and then are cleaved in response to cellular triggers such as reductive reaction, light, and low acid. The well-designed SRD micelles have been explored as controlled/enhanced delivery vehicles of drugs and genes. For future design and development of effective stimuli-responsive degradable micelles toward tumor-targeting delivery applications in vivo, a high degree of control over degradation for tunable release of encapsulated anticancer drugs as well as bioconjugation for active tumor-targeting is required.
QCD at a finite density of static quarks

Abstract Recently, cluster methods have been used to solve a variety of sign problems including those that arise in the presence of fermions. In all cases an analytic partial re-summation over a class of configurations in the path integral was necessary. Here the new ideas are illustrated using the example of QCD at a finite density of static quarks. In this limit the sign problem simplifies since the fermionic part decouples. Furthermore, the problem can be solved completely when the gauge dynamics is replaced by a Potts model. On the other hand in QCD with light quarks the solution will require a partial re-summation over both fermionic and gauge degrees of freedom. The new approach points to unexplored directions in the search for a solution to this more challenging sign problem.
The allocation of badly needed goods to low-income consumers: A system of central planning without redistributive taxation☆

Abstract A simple planning model is constructed that is designed to deliver more of certain badly needed goods to poor consumers than they would receive under a competitive system. The model increases the supply of the badly needed goods, while minimizing the cost, in terms of welfare losses, of the increased production to those consumers for whom the goods are relatively unimportant. Simulation examples are used to demonstrate the methodology, which is sufficiently general to be used to represent many different central-planning systems.
Two-Dimensional Flow Analysis of a Laboratory Centrifugal Pump

Two-dimensional potential flow was used to determine the velocity field within a laboratory centrifugal pump. In particular, the finite element techniquie was used to model the impeller and volute simultaneously. The rotatiion of the impeller within the volute was simulated by using steady-state solutions with the impeller in ten different angular orientations. This allowed the interaction between the impeller and the volute to develop naturally as a result of the solution. The results for the complete pump model showed that there are circumferential asymmetries in the velocity field, even at the design flow rate
The Simple Economics of Approximately Optimal Auctions

The intuition that profit is optimized by maximizing marginal revenue is a guiding principle in microeconomics. In the classical auction theory for agents with quasi-linear utility and single-dimensional preferences, BR89 show that the optimal auction of M81 is in fact optimizing marginal revenue. In particular Myerson's virtual values are exactly the derivative of an appropriate revenue curve. This paper considers mechanism design in environments where the agents have multi-dimensional and non-linear preferences. Understanding good auctions for these environments is considered to be the main challenge in Bayesian optimal mechanism design. In these environments maximizing marginal revenue may not be optimal, and furthermore, there is sometimes no direct way to implement the marginal revenue maximization mechanism. Our contributions are three fold: we characterize the settings for which marginal revenue maximization is optimal (by identifying an important condition that we call revenue linearity), we give simple procedures for implementing marginal revenue maximization in general, and we show that marginal revenue maximization is approximately optimal. Our approximation factor smoothly degrades in a term that quantifies how far the environment is from an ideal one (i.e., where marginal revenue maximization is optimal). Because the marginal revenue mechanism is optimal for well-studied single-dimensional agents, our generalization immediately extends many approximation results for single-dimensional agents to more general preferences. Finally, one of the biggest open questions in Bayesian algorithmic mechanism design is in developing methodologies that are not brute-force in size of the agent type space (usually exponential in the dimension for multi-dimensional agents). Our methods identify a sub problem that, e.g., for unit-demand agents with values drawn from product distributions, enables approximation mechanisms that are polynomial in the dimension.
On the torsion of Jacobians of principal modular curves of level 3 n

We demonstrate that the 3-power torsion points of the Jacobians of the principal modular curves X(3 n ) are fixed by the kernel of the canonical outer Galois representation of the pro-3 fundamental group of the projective line minus three points. The proof proceeds by demonstrating the curves in question satisfy a two-part criterion given by Anderson and Ihara. Two proofs of the second part of the criterion are provided; the first relies on a theorem of Shimura, while the second uses the moduli interpretation.
Bound States of Type I' D-particles and Enhanced Gauge Symmetry

Abstract Duality between the E8 × E8 heterotic string Type I′ theory predicts a tower of D(irichlet)-particle bound states corresponding to perturbative heterotic string states. In the limit of infinite Type I′ coupling, some of these bound states become massless, giving rise to enhanced E8 × E8 gauge symmetry. By taking a different infinite coupling limit, one can recover the E8 × E8 gauge bosons of M-theory, compactified on S 1 / Z 2 . In this paper we use the matrix model description of the D-particle dynamics to study these bound states. We find results consistent with the chain of dualities and clarify a number of issues that arise in the application of the matrix mechanics to this system.
Parametric study of shock‐induced transport and energization of relativistic electrons in the magnetosphere

[1] The sudden appearance of a new radiation belt consisting of electrons with energies greater than 13 MeV near 2.5 Earth radii (RE), was observed by CRRES (Combined Radiation and Release Experiment Satellite) on 24 March 1991. Li et al. (1993) showed that the cause was an electromagnetic pulse within the Earth's magnetosphere caused by an unusually strong, fast shock in the solar wind. Sudden shock-induced injections of electrons with energies above 10 MeV to equatorial distances within 2.5 RE are extremely rare because of the intensity of the shock required. In the current study, the propagation velocity parameter and electric field amplitude of pulses within the magnetosphere in the Li et al. model were varied from 750 to 2500 km/s and 70 to 400 mV/m, respectively. It was found that a stronger electric field shifted the peak of the resultant relativistic electron population toward the Earth. Doubling the electric field amplitude from 120 to 240 mV/m moved the peak of the injected electrons with energies above 13 MeV from 2.8 to 2.4 RE. However, as the electric field pulse becomes even larger, the increase in response diminishes. This asympotic behavior shows that it is extremely difficult to produce energetic electron injections inside two Earth radii. The nominal propagation velocity (velocity parameter) is compared to the radial propagation velocities that would have been measured under this model and others and compared to observation. It is found that although the model radial velocity is smaller than the velocity parameter and decreasing with radial distance, it is faster than MHD results and observations. Decreasing the nominal propagation velocity of the pulse within the magnetosphere from 2500 km/s to 1400 km/s also moved the peak of the injected electrons with energies above 13 MeV slightly closer to the Earth. However, at velocities smaller than approximately 1200 km/s the number of electrons injected within 2.5 Earth radii with energies above 13 MeV greatly decreased. Halving the velocity from 2000 to 1000 km/s shifted the peak of electrons with energy greater than 13 MeV from L = 2.6 to L = 2.4 but produced a count rate reduced by a factor of more than 250, resulting in no significant new radiation belt. These results show that the typical large electromagnetic impulses caused by interplanetary shocks, with amplitudes of the order of 10 mV/m, are more than an order of magnitude too small to produce any significant new radiation belts within 2.5 Earth radii with energies of the order of 10 MeV. Contributing to the difficulty in producing such a new belt is the need for an already relativistic electron population with adequate flux beyond geosynchronous orbit. These results thus also help explain the rarity of events such as the 24 March 1991 injection.
The need of considering the interactions in the analysis of screening designs

Fractional factorial designs are widely used experimental plans for identifying important factors in screening studies where many factors are involved. Traditionally, Plackett–Burman (PB) and related designs are employed in such studies because of their cost efficiencies. The caveat with the use of PB designs is that interactions among factors are implicitly assumed to be non-existent. However, there are many practical situations where some interactions are significant and ignoring them can result in wrong statistical inferences, including biased estimates, missing out on important factors, and detection of spurious factors. We reanalyze data for three chemical experiments using the Hamada and Wu's method and showed that we are able to identify significant interactions in each of these chemical experiments and improve the overall fit of the model. In addition, we analyze the data using a Bayesian approach that confirms our findings. In both approaches, graphical tools are employed along with easily available software for analysis. Copyright © 2009 John Wiley & Sons, Ltd.
A Protocol To Generate Phthaloyl Peroxide in Flow for the Hydroxylation of Arenes

A flow protocol for the generation of phthaloyl peroxide has been developed. This process directly yields phthaloyl peroxide in high purity (>95%) and can be used to bypass the need to isolate and recrystallize phthaloyl peroxide, improving upon earlier batch procedures. The flow protocol for the formation of phthaloyl peroxide can be combined with arene hydroxylation reactions and provides a method for the consumption of peroxide as it is generated to minimize the accumulation of large quantities of peroxide.
Multicomponent Polymers of Poly(Lactic Acid) Macromonomers with Methacrylate Terminal and Copolymers of Poly(2-Hydroxyethyl Methacrylate)

Abstract Poly(lactic acid) macromonomers with methacrylate terminal functionality have been synthesized from the cyclic dimer of lactic acid (referred to as lactide) with 2-hydroxyethyl methacrylate (HEMA) as initiator and stannous 2-ethyl hexanoate as catalyst. The macromonomers were characterized with FT-IR, NMR, GPC, DSC, WAXS, and CD. The molecular weights of the macromonomers ranging from M n 1425 to 19,169 are predictable from the lactide/HEMA ratio in the polymerization feeds. The properties of the macromonomers vary with the stereochemistry of the lactide and the composition. Circular dichroism measurements demonstrate that there is little racemization during polymerization.