cssi/SciSciGPT-SciSciNet huggingface dataset:
The Set of Packing and Covering Densities of Convex Disks

For every convex disk $$K$$K (a convex compact subset of the plane, with non-void interior), the packing density $$\delta (K)$$ź(K) and covering density $${\vartheta (K)}$$ź(K) form an ordered pair of real numbers, i.e., a point in $$\mathbb{R }^2$$R2. The set $$\varOmega $$Ω consisting of points assigned this way to all convex disks is the subject of this article. A few known inequalities on $$\delta (K)$$ź(K) and $${\vartheta (K)}$$ź(K) jointly outline a relatively small convex polygon $$P$$P that contains $$\varOmega $$Ω, while the exact shape of $$\varOmega $$Ω remains a mystery. Here we describe explicitly a leaf-shaped convex region $$\Lambda $$ź contained in $$\varOmega $$Ω and occupying a good portion of $$P$$P. The sets $$\varOmega _T$$ΩT and $$\varOmega _L$$ΩL of translational packing and covering densities and lattice packing and covering densities are defined similarly, restricting the allowed arrangements of $$K$$K to translated copies or lattice arrangements, respectively. Due to affine invariance of the translative and lattice density functions, the sets $$\varOmega _T$$ΩT and $$\varOmega _L$$ΩL are compact. Furthermore, the sets $$\varOmega , \,\varOmega _T$$Ω,ΩT and $$\varOmega _L$$ΩL contain the subsets $$\varOmega ^\star , \,\varOmega _T^\star $$Ωź,ΩTź and $$\varOmega _L^\star $$ΩLź respectively, corresponding to the centrally symmetric convex disks $$K$$K, and our leaf $$\Lambda $$ź is contained in each of $$\varOmega ^\star , \,\varOmega _T^\star $$Ωź,ΩTź and $$\varOmega _L^\star $$ΩLź.
Multiple Light Scattering by Spherical Dielectric Particles

The general multiple light-scattering theory due to Hartel for the angular scattering from high concentrations of spherical scattering particles has been calculated for the case of large spheres. Experimental data for the multiple scattering for various volume concentrations of monodisperse polystyrene latex particles are compared with calculations of the theory. The results indicate that the theory as generalized in this paper is a valid general multiple light-scattering theory for fairly high concentrations of spherical scattering particles.
Changes in rotator cuff muscle volume, fat content, and passive mechanics after chronic detachment in a canine model.

BackgroundLong-standing tears of the rotator cuff can lead to substantial and perhaps irreversible changes in the affected rotator cuff muscles. We developed a chronic rotator cuff tear in a canine model to investigate and quantify the time-related changes in passive mechanics, volume, and fat of th
Nonlinear Criterion for the Stability of Molecular Clouds

Dynamically significant magnetic fields are routinely observed in molecular clouds, with mass-to-flux ratio λ ≡ (2π)Σ/B ~ 1 (here Σ is the total column and B the field strength). It is widely believed that "subcritical" clouds with λ < 1 cannot collapse, based on virial arguments by Mestel and Spitzer and a linear stability analysis by Nakano and Nakamura. Here we confirm, using high-resolution numerical models that begin with a strongly supersonic velocity dispersion, that this criterion is a fully nonlinear stability condition. All the high-resolution models with λ ≤ 0.95 form "Spitzer sheets" but collapse no further. All models with λ ≥ 1.02 collapse to the maximum numerically resolvable density. We also investigate other factors determining the collapse time for supercritical models. We show that there is a strong stochastic element in the collapse time: models that differ only in details of their initial conditions can have collapse times that vary by as much as a factor of 3. The collapse time cannot be determined from just the velocity dispersion; it depends also on its distribution. Finally, we discuss the astrophysical implications of our results.
Substitution behavior and stable charge carrier species in long-bond length layered cuprates

The stabilities of charge carriers, the transport properties, and the defect structures of the layered, quadruple perovskite La2Ba2Cu2Sn2O11 have been investigated by chemical substitutions, powder X-ray diffraction, and simultaneous high-temperature electrical conductivity and thermopower measurements. The in-plane copper-oxygen bond lengths, in cooperation with the copper-coordination environment, are observed to control the chemical solubilities, stable charge carrier species, and oxygen defects. Potential n-type substitutions are successful via the substitution of niobium for tin. However, oxygen defects are demonstrated to be important compensation species for the incorporation of the substituted cations and in the mediation of the charge carrier concentration with the ambient atmosphere in the near-synthesis temperature region. These materials are intrinsic semiconductors and display crossover from n-type to p-type behavior with increasing oxygen partial pressure, from 10 -5 to 1 atm pO2, in the temperature range from 600 to 800 °C. Furthermore, the transport parameters are shown to be composition-dependent for these compounds and asymmetric with respect to electron and electron-hole conduction, in contrast to other layered copper oxides. Specifics of the inner architecture of layered copper oxides, particularly residual internal stresses between layers, are discussed with respect to their control over the redox behavior of copper-oxygen networks, and the implications of these findings are elaborated on with respect to the realization of new n-type superconductors.
A Mordell inequality for lattices over maximal orders

In this paper we prove an analogue of Mordell's inequality for lattices in finite-dimensional complex or quaternionic Hermitian space that are modules over a maximal order in an imaginary quadratic number field or a totally definite rational quaternion algebra. This inequality implies that the 16-dimensional Barnes-Wall lattice has optimal density among all 16-dimensional lattices with Hurwitz structures.
“The Hitlerian Rule of Quotas”: Racial Conservatism and the Politics of Fair Employment Legislation in New York State, 1941–1945

In 1945, New York became the first state of two dozen states in the North to adopt a fair employment practices (FEP) law. Passing with bipartisan support, New York's Ives-Quinn law prohibited discrimination in employment and established a new state commission with administrative authority to enforce the law. This article examines the politics behind the passage of Ives-Quinn, drawing on a wide range of underutilized or undertapped primary sources. I find that a new bipartisan, interfaith, interracial coalition of liberals - championing "freedom from discrimination" - was the main force propelling the campaign forward. Opposing them was a coalition of conservative Republicans, business interests, and rural and suburban whites, who together staged a major insurgency that nearly derailed Ives-Quinn. This conservative coalition professed to share the ideal of racial equality, but argued that the passage of FEP legislation - while facially race-neutral - would lead to the development of racial quotas, grant preferential treatment to unqualified minorities, and foster rather than reduce color-consciousness. Conservatives eventually fell to defeat, but the battle over Ives-Quinn nonetheless represented a watershed moment in modern American political history.
State and federal tax equity: Estimates before and after the Tax Reform Act of 1986

The progressivity and equity of both state and federal individual income taxes, as well as the combined system of both taxes, are examined before and after the federal Tax Reform Act of 1986 using a variety of measures applied to federal Statistics of Income individual income tax data; state taxes are calculated using TAXSIM. Our findings are as follows: First, in both 1985 and 1987, state personal income taxes were generally less progressive and more horizontally equitable than the federal system. Second, in moving from 1985 to 1987, state personal income tax systems generally displayed decreased progressivity and horizontal inequity. The combination of the two systems displayed generally lower progressivity and horizontal equity scores when we compare 1987 to 1985. Last, the after-tax income distribution became more unequal when we compared 1987 to 1985.
Optical properties of cation-substituted zinc oxide.

Zinc oxide (ZnO)-based optoelectronics has emerged as a frontier area in semiconductor research in recent years. In the design of ZnO-based optoelectronic devices, cation-substituted ZnO serves as essential components for the desired device functions. Band-gap engineering by cation substitution enables the facile preparation of barrier layers and quantum wells in device structures. Wurtzite solid solutions Zn1−xMgxO, Zn1−xCdxO, and Zn1−xBexO have been reported as examples where band gaps are gradually modulated as functions of x. In this contribution, we present an overview of composition-dependent band-gap variations of Zn1−xMxO solid solutions. In addition, we describe the optical properties and microstructural evolution in polycrystalline Zn1−xMgxO (0 ≤ x ≤ 0.15). It is proposed that chemical strain associated with cation substitution has an impact on the band-gap magnitude, crystallite morphology, and optical defects.
Stable superstring relics

Abstract We investigate the cosmological constraints on exotic stable matter states which arise in realistic free fermionic superstring models. These states appear in the superstring models due to a “Wilsonline” breaking of the unifying non-abelian gauge symmetry. In the models that we consider the unifying SO(10) gauge symmetry is broken at the string level to SO(6) x SO(4), SU(5) x U(1) or SU(3) x SU(2) x U(1)2. The exotic matter states are classified according to the patterns of the SO(10) symmetry breaking. In SO(6) x SO(4) and SU(5) x U(1) type models one obtains fractionally charged states with Q e.m. = ± 1 2 . In SU (3) x SU (2) x U(1)2 type models one also obtains states with the regular charges under the Standard Model gauge group but with “fractional” charges under the U(1)z′ symmetry. These states include down-like color triplets and electroweak doublets, as well as states which are Standard Model singlets. By analyzing the renormalizable and nonrenormalizable terms of the superpotential in a specific superstring model, we show that these exotic states can be stable. We investigate the cosmological constraints on the masses and relic density of the exotic states. We propose that, while the abundance and the masses of the fractionally charged states are highly constrained, the Standard Model-like states, and in particular the Standard Model singlet, are good dark matter candidates.
Synthesis of Cyclo-2,2‘:4‘,4‘‘:2‘‘,2‘‘‘:4‘‘‘,4‘‘‘‘:2‘‘‘‘,2‘‘‘‘‘:4‘‘‘‘‘,4-sexipyridine

Preparation of the title compound (2) by use of Stille couplings and a Krohnke pyridine synthesis is described. By application of the Stille coupling reaction, preparation and functionalization of quater- and quinquepyridines 26, 27, and 28 were achieved. Elaboration of quinquepyridine 27 to the pyridinium salt 30 bearing a protected enal allowed for the synthesis of 2 by a one-pot deprotection/Krohnke reaction in nine steps from 4,4‘-bipyridine. Use of the Krohnke pyridine synthesis has been applied to prepare sexipyridine dibromide 19, but attempts to induce a macrocyclization via metal-mediated (Pd/Ni/Cu) aryl−aryl coupling procedures proved unsuccessful. Acetylene-bridged sexipyridines 3a and 3b incorporating 2,2‘-bipyridine units proved to be inaccessible via sp−sp2 or sp−sp coupling protocols.
A survey of read-only memories

Consider the problem of the design of a combinational circuit with A inputs and B outputs, where each of the output variables is given as a Boolean function of the input variables. Such a circuit might be part of the control unit of a digital computer, where the A inputs are the operation code of an instruction, and the B outputs are the signals which directly control the opening and closing of gates throughout the machine to effect an execution of that instruction. The circuit might be a code converter, where the A inputs are an input code (for example, the machine-code of an alphanumeric character); and the B outputs are an output code (for example, the pattern of signals required for a display of that character). The circuit might be a table look-up device, where, for example, the input variables are a code for the numeric value of a given argument, and the output variables are a code for the value of some function of that argument. Finally, the circuit might be considered as a memory, with fixed information stored, where the A input bits are an address, and the B output bits are the word stored at that address. It is called a "read-only" or "fixed" memory if the information stored is not alterable at electronic speeds.
Kinetics of Heterogeneous Catalyzed Reactions

Abstract The literature on heterogeneous catalytic kinetics is enormous, For this reason, the author has chosen to be selective rather than comprehensive. This review discusses, semihistorically and by reference to illustrative papers, the development of ideas and trends in research within the chosen topics. By way of warning: The author's interest in kinetics and chemisorption has been developing for some 50 years [1–6], One hopes that prejudices have softened over the years, but one knows they have not disappeared.
An area-efficient VLSI implementation for programmable FIR filters based on a parameterized divide and conquer approach

In this paper, we propose an optimal VLSI implementation for a class of programmable FIR filters with binary coefficients, whose architecture is based on a parameterized divide and conquer approach. The proposed design is shown to be easily extendable to FIR filters with multibit coefficients of arbitrary sign. The area efficiency achieved in comparison to direct form realization is demonstrated by VLSI implementation examples, synthesized in TSMC [email protected] single poly six metal layer CMOS process using state-of-art VLSI EDA tools. The possible saving in average power consumption is estimated using gate-level power analysis. Suggestions for applications and topics for further research conclude the paper.
Three-Phase Flash in Compositional Simulation Using a Reduced Method

CO2 flooding at low temperatures often results in three or more hydrocarbon-phases. Multiphase compositional simulation must accurately simulate such gas floods. Drawbacks of modeling three hydrocarbon-phases are the increased computational time and convergence problems associated with flash calculations. Use of a reduced method is a potential solution.
Top-quark decay via R-parity violating interactions at the Tevatron

Abstract We consider the top-quark decay t→ τ b and t→τb χ 0 1 via explicit R -parity violating interactions in SUSY theories. We discuss the observability of those channels at the Fermilab Tevatron collider. The existing Tevatron data indicate a 95% confidence level upper bound on the coupling to be 0.94 (0.63) for a long-lived (short-lived) χ 0 1 with m τ =70 GeV. At Tevatron Run II with an integrated luminosity of 2 (10) fb −1 , one can obtain a 2 σ constraint as 0.38 (0.24) for a long-lived χ 0 1 and 0.29 (0.19) for a short-lived χ 0 1 , beyond the current indirect limit.
Realization of a skillful bridge bidding program

The problem of bidding at contract bridge is an "intellectual" task which has never before been performed skillfully by a computer program. Only Carley has made the attempt to handle this problem and his program used a very crude treatment; as a result, inferior contracts were produced because bidding requires many fine lines of distinction which his approach could not make.
Eddington Limit and Radiative Transfer in Highly Inhomogeneous Atmospheres

Radiation-dominated accretion disks are likely to be subject to the "photon bubble" instability, which may lead to strong density inhomogeneities on scales much shorter than the disk scale height. Such disks, and magnetized, radiation-dominated atmospheres in general, could radiate well above the Eddington limit without being disrupted. When density contrasts become large over distances of the order of the photon mean free path, radiative transfer cannot be described adequately using either the standard diffusion approximation or existing prescriptions for flux-limited diffusion. Using analytical and Monte Carlo techniques, we consider the effects of strong density gradients deep within radiation- and scattering-dominated atmospheres. We find that radiation viscosity, i.e., the off-diagonal elements of the radiation stress tensor, has an important effect on radiative transfer under such conditions. We compare analytical and numerical results in the specific case of a plane-parallel density-wave structure and calculate Eddington enhancement factors due to the porosity of the atmosphere. Our results can be applied to the study of dynamical coupling between radiation forces and density inhomogeneities in radiation-dominated accretion disks in two or three dimensions.
Defaults and interest rates in international lending

Abstract Since lenders cannot observe the riskiness of the projects that borrowers could choose, interest rates alone cannot be used as an instrument to discipline borrowers. A credible threat to exclude borrowers who default more than a certain number of times from participating in the capital markets makes international debt contracts incentive compatible. Since larger borrowers get fewer chances to default, they choose safer projects and are therefore charged lower interest rates. Also, borrowers, after each successive default, switch to safer and safer projects, which may result in lower and lower interest rates. This paper provides empirical evidence supporting these two predictions.
Dividend-Yield Strategies in the Canadian Stock Market

The “Dogs of the Dow” strategy has become an increasingly popular investment strategy for unit investment trusts, resulting in superior performance for U.S.-based investors. To examine its effectiveness for Canadian investors, we applied this high-dividend-yield strategy to the Toronto 35 Index for the first 10 years of the index's existence. The 10 top-performing portfolios' higher compound returns were sufficient to compensate for taxes and transaction costs. Perhaps more important, both the Sharpe ratio, which measures excess return to total risk, and the Treynor index, which measures excess return to market risk, indicate that the strategy produced higher risk-adjusted returns than the Toronto 35. The Dogs strategy also performed well against the broader, but similar, Toronto Stock Exchange 300 Index.
Crystal structure of hormone-bound atrial natriuretic peptide receptor extracellular domain: rotation mechanism for transmembrane signal transduction.

A cardiac hormone, atrial natriuretic peptide (ANP), plays a major role in blood pressure and volume regulation. ANP activities are mediated by a single span transmembrane receptor carrying intrinsic guanylate cyclase activity. ANP binding to its extracellular domain stimulates guanylate cyclase activity by an as yet unknown mechanism. Here we report the crystal structure of dimerized extracellular hormone-binding domain in complex with ANP. The structural comparison with the unliganded receptor reveals that hormone binding causes the two receptor monomers to undergo an intermolecular twist with little intramolecular conformational change. This motion produces a Ferris wheel-like translocation of two juxtamembrane domains in the dimer with essentially no change in the interdomain distance. This movement alters the relative orientation of the two domains by a shift equivalent to counterclockwise rotation of each by 24°. These results suggest that transmembrane signaling by the ANP receptor is initiated via a hormone-induced rotation mechanism.
Note on loss of regularity for solutions of the $3$-D incompressible Euler and related equations

One of the central problems in the mathematical theory of turbulence is that of breakdown of smooth (indefinitely differentiable) solutions to the equations of motion. In 1934 J. Leray advanced the idea that turbulence may be related to the spontaneous appearance of singularities in solutions of the 3—D incompressible Navier-Stokes equations. The problem is still open. We show in this report that breakdown of smooth solutions to the 3—D incompressible slightly viscous (i.e. corresponding to high Reynolds numbers, or “highly turbulent”) Navier-Stokes equations cannot occur without breakdown in the corresponding solution of the incompressible Euler (ideal fluid) equation. We prove then that solutions of distorted Euler equations, which are equations closely related to the Euler equations for short term intervals, do breakdown.
The Proteins of Membranes

Abstract Proteins constitute the largest fraction by weight of most membranes, and their properties are critical to membrane functions. A brief discussion is given of some salient theoretical and experimental advances of the last decade in our understanding of the structures of proteins in membranes, which have led to the fluid mosaic model of membrane structure, and to new insights into the molecular mechanisms of membrane functions.
Photometric Identification of Cool White Dwarfs

We investigate the use of a narrowband DDO51 filter for photometric identification of cool white dwarfs. We report photometric observations of 30 known cool white dwarfs with temperatures ranging from 10,000 K down to very cool temperatures (?3500 K). Follow-up spectroscopic observations of a sample of objects selected using this filter and our photometric observations show that DDO51 filter photometry can help select cool white dwarf candidates for follow-up multiobject spectroscopy by rejecting 65% of main-sequence stars with the same broadband colors as the cool white dwarfs. This technique is not selective enough to efficiently feed single-object spectrographs. We present the white dwarf cooling sequence using this filter. Our observations show that very cool white dwarfs form a sequence in the r - DDO versus r - z color-color diagram and demonstrate that significant improvements are needed in white dwarf model atmospheres.
Executive compensation of large acquirors in the 1980s

Abstract To examine the role of executive compensation in corporate acquisition decisions, we compare executive compensation of firms undertaking large acquisitions to a control sample of non-acquirors. Before the acquisitions, we find a positive relation between firm size and compensation for executives of acquirors; we do not find such a relation for non-acquirors. This result suggests an ex ante expectation that larger firm size will result in larger managerial remuneration. Ex post, however, large acquisitions have a small positive effect on total compensation. When we separate good from bad acquisitions, we find that good acquisitions increase compensation, whereas bad acquisitions do not have a positive effect on compensation.
Optimizing i/o costs of multi-dimensional queries using bitmap indices

Bitmap indices are efficient data structures for processing complex, multi-dimensional queries in data warehouse applications and scientific data analysis. For high-cardinality attributes, a common approach is to build bitmap indices with binning. This technique partitions the attribute values into a number of ranges, called bins, and uses bitmap vectors to represent bins (attribute ranges) rather than distinct values. In order to yield exact query answers, parts of the original data values have to be read from disk for checking against the query constraint. This process is referred to as candidate check and usually dominates the total query processing time. In this paper we study several strategies for optimizing the candidate check cost for multi-dimensional queries. We present an efficient candidate check algorithm based on attribute value distribution, query distribution as well as query selectivity with respect to each dimension. We also show that re-ordering the dimensions during query evaluation can be used to reduce I/O costs. We tested our algorithm on data with various attribute value distributions and query distributions. Our approach shows a significant improvement over traditional binning strategies for bitmap indices.
Naturalness Versus Supersymmetric Non-renormalization Theorems

We give an intuitive proof of a new non-renormalization theorem in supersymmetric field theories. It applies both perturbatively and non-perturbatively. The superpotential is not renormalized in perturbation theory but receives non-perturbative corrections. However, these non-perturbative corrections are not generic functions of the fields consistent with the symmetries. Certain invariant terms are not generated. This violation of naturalness has applications to dynamical supersymmetry breaking.
Child Care Subsidies and Childhood Obesity

In this paper, we study the impact of child care subsidy receipt on low-income children’s weight outcomes in the fall and spring of kindergarten using data from the Early Childhood Longitudinal Study, Kindergarten Cohort. Our results suggest that subsidy receipt is associated with increases in BMI and a greater likelihood of being overweight and obese. Using quantile regression methods, we find substantial variation in subsidy effects across the BMI distribution. Specifically, child care subsidies have no effect on BMI at the lower end of the distribution, inconsistent effects in the middle of the distribution, and large effects at the top of the distribution. Our results point to the use of non-parental child care, particularly center-based services, as the key mechanism through which subsidies influence children’s weight outcomes.
Trajectory Design for Mechanical Control Systems: from Geometry to Algorithms

Trajectory design is a key problem in a vast array of robotic applications including the design of autonomous agile vehicles and of minimalist manipulators. This problem can be accurately formalized within the language of affine connections and of geometric control theory. This paper surveys recent results on kinematic controllability and on oscillatory controls. The treatment emphasizes how to translate geometric controllability conditions into algorithms for generating and tracking trajectories.
Creating a software-engineering knowledge base

A description is given of the CASE/MVS project, which combines knowledge engineering and software engineering to provide a powerful computer-aided software engineering (CASE) environment for developing the MVS/XA operating system. The components and characteristics of the knowledge base are discussed. Aspects of the CASE/MVS project are examined, namely, managing source specifications, creating and analyzing static models, dynamic analysis, and code generation. >
THE STRUCTURAL ELABORATION OF BOARD INDEPENDENCE: EXECUTIVE POWER, INSTITUTIONAL LOGICS, AND THE ADOPTION OF CEO-ONLY BOARD STRUCTURES IN U.S. CORPORATE GOVERNANCE

This study builds on structural elaboration theory by developing a model to explain the adoption of board structures that appear to conform to the prevailing institutional logic, but which in fact contradict it. We test our theory with the case of CEO-only board structures, a formal increase in board independence that prior research has shown to lead to greater CEO entrenchment rather than increased shareholder value. Using an event history analysis of the Fortune 250 over a 27-year period, we examine three mechanisms that drive its adoption: executive interests, executive power, and elaboration opportunities. We show that the CEO-only structure is more likely to occur in firms in which a higher proportion of insiders predate the CEO, and in which the CEO has greater formal power and agenda control. We also find that powerful CEOs are more likely to realize the structural change following institutional opportunities, such as the passage of Sarbanes-Oxley (SOX), and organizational contingencies, such as positive changes in firm performance. By exploring the mechanisms leading to the proliferation of the CEO-only structure, our study contributes to sociopolitical perspectives on corporate governance, as well as to theories of institutional logics and structural elaboration
Universities as research partners in publicly supported entrepreneurial firms

Partnerships between universities and industrial firms can play a key role in enhancing competitiveness because they provide a conduit for the spillover of knowledge from the academic organization where knowledge is created to the firm where it is transformed into innovative activity. We set forth in this paper a model of industry/university participation, and we test the model empirically, using research project data on entrepreneurial firms that were funded through the US Department of Energy's Small Business Innovation Research (SBIR) program. We find that larger firms are more likely to be involved in a research partnership with a university, in general, as are firms with founders who have an academic background. We find the latter result holds across disaggregated types of university partnerships, as well. We find no empirical evidence that the size of the SBIR award influences the likelihood of a research partnership.
Convergence of a Class of Decentralized Beamforming Algorithms

One of the key issues in decentralized beamforming is the need to phase-align the carriers of all the sensors in a wireless sensor network. Recent work in this area has shown the viability of certain methods that incorporate single-bit feedback from a beacon. This paper analyzes the behavior of the method (showing conditions for convergence in distribution and also giving a concrete way to calculate the final distribution of the convergent ball) and then generalizes the method in three ways. First, by incorporating both negative and positive feedback it is possible to double the convergence rate of the algorithm without adversely effecting the final variance. Second, a way of reducing the amount of energy required (by reducing the number of transmissions needed for convergence) is shown; its convergence and final variance can also be conveniently described. Finally, a wideband analog is proposed that operates in a decentralized manner to align the time delay (rather than the phase) between sensors.
Preparation of optically active β-carboxyaspartic acid derivatives via Pd(0)-catalyzed asymmetric substitution of Schiff base acetates

Abstract Optically active β-carboxyaspartic acid derivative 6 (77% ee) was obtained in 48% total yield from the coupling of Schiff base acetate 3 with sodium dimethyl malonate in the presence of 5% Pd(OAc) 2 -(2 S ,4 S )-BPPM followed by a single recrystallization. Phase-transfer catalyzed alkylation of malonates 6 affords β-substituted ASA derivatives 7 in excellent yield without racemization at the α-carbon.
Flutter and Divergence Analysis using the Generalized Aeroelastic Analysis Method

The Generalized Aeroelastic Analysis Method (GAAM) is applied to the analysis of three well-studied checkcases: restrained and unrestrained airfoil models, and a wing model. An eigenvalue iteration procedure is used for converging upon roots of the complex stability matrix. For the airfoil models, exact root loci are given which clearly illustrate the nature of the flutter and divergence instabilities. The singularities involved are enumerated, including an additional pole at the origin for the unrestrained airfoil case and the emergence of an additional pole on the positive real axis at the divergence speed for the restrained airfoil case. Inconsistencies and differences among published aeroelastic root loci and the new, exact results are discussed and resolved. The generalization of a Doublet Lattice Method computer code is described and the code is applied to the calculation of root loci for the wing model for incompressible and for subsonic flow conditions. The error introduced in the reduction of the singular integral equation underlying the unsteady lifting surface theory to a linear algebraic equation is discussed. Acknowledging this inherent error, the solutions of the algebraic equation by GAAM are termed 'exact.' The singularities of the problem are discussed and exponential series approximations used in the evaluation of the kernel function shown to introduce a dense collection of poles and zeroes on the negative real axis. Again, inconsistencies and differences among published aeroelastic root loci and the new 'exact' results are discussed and resolved. In all cases, aeroelastic flutter and divergence speeds and frequencies are in good agreement with published results. The GAAM solution procedure allows complete control over Mach number, velocity, density, and complex frequency. Thus all points on the computed root loci can be matched-point, consistent solutions without recourse to complex mode tracking logic or dataset interpolation, as in the k and p-k solution methods.
Effects of rapid prey evolution on predator–prey cycles

We study the qualitative properties of population cycles in a predator–prey system where genetic variability allows contemporary rapid evolution of the prey. Previous numerical studies have found that prey evolution in response to changing predation risk can have major quantitative and qualitative effects on predator–prey cycles, including: (1) large increases in cycle period, (2) changes in phase relations (so that predator and prey are cycling exactly out of phase, rather than the classical quarter-period phase lag), and (3) “cryptic” cycles in which total prey density remains nearly constant while predator density and prey traits cycle. Here we focus on a chemostat model motivated by our experimental system (Fussmann et al. in Science 290:1358–1360, 2000; Yoshida et al. in Proc roy Soc Lond B 424:303–306, 2003) with algae (prey) and rotifers (predators), in which the prey exhibit rapid evolution in their level of defense against predation. We show that the effects of rapid prey evolution are robust and general, and furthermore that they occur in a specific but biologically relevant region of parameter space: when traits that greatly reduce predation risk are relatively cheap (in terms of reductions in other fitness components), when there is coexistence between the two prey types and the predator, and when the interaction between predators and undefended prey alone would produce cycles. Because defense has been shown to be inexpensive, even cost-free, in a number of systems (Andersson et al. in Curr Opin Microbiol 2:489–493, 1999: Gagneux et al. in Science 312:1944–1946, 2006; Yoshida et al. in Proc Roy Soc Lond B 271:1947–1953, 2004), our discoveries may well be reproduced in other model systems, and in nature. Finally, some of our key results are extended to a general model in which functional forms for the predation rate and prey birth rate are not specified.
A multicomponent Ni-, Zr-, and Cu-catalyzed strategy for enantioselective synthesis of alkenyl-substituted quaternary carbons.

The availability of enantiomerically enriched carbonyl-containing compounds is essential to the synthesis of biologically active molecules. Since catalytic enantioselective conjugate addition (ECA) reactions directly generate the latter valuable class of molecules, the design and development of such protocols represents a compelling objective in modern chemistry. Herein, we disclose the first solution to the problem of ECA of alkenyl groups to acyclic trisubstituted enones, an advance achieved by adopting an easily modifiable and fully catalytic approach. The requisite alkenylaluminum reagents are synthesized with exceptional site- and/or stereoselectivity by a Ni-catalyzed hydroalumination process, and the necessary enones are prepared through a site- and stereoselective zirconocene-catalyzed carboalumination/acylation reaction. The all-catalytic procedure is complete within four hours, furnishing the desired products in up to 77 % overall yield and 99:1 enantiomeric ratio.
Bias reduction in traceroute sampling - towards a more accurate map of the internet

Traceroute sampling is an important technique in exploring the internet router graph and the autonomous system graph. Although it is one of the primary techniques used in calculating statistics about the internet, it can introduce bias that corrupts these estimates. This paper reports on a theoretical and experimental investigation of a new technique to reduce the bias of traceroute sampling when estimating the degree distribution. We develop a new estimator for the degree of a node in a traceroute-sampled graph; validate the estimator theoretically in Erdos-Renyi graphs and, through computer experiments, for a wider range of graphs; and apply it to produce a new picture of the degree distribution of the autonomous system graph.
Homology theory for the set-theoretic Yang&#8211;Baxter equation and knot invariants from generalizations of quandles

A homology theory is developed for set-theoretic Yang-Baxter equations, and knot invariants are constructed by generalized colorings by biquandles and Yang-Baxter cocycles.
Management, Law, and the Pursuit of the Public Good in Public Administration

The tension between managerialism and legalism in public administration has been a recurring theme at Minnowbrook conferences. This tension, increasingly evident in the literature, is couched in the often-conflicting values of efficiency and performance, on one hand, and legal and democratic values such as accountability, equality, and transparency, on the other hand. Building on conversations we began at Minnowbrook III, we specify a three-part proposal through which the legal and managerial approaches to US public administration might be better integrated. At a time when public administrative reforms potentially exacerbate the law management tension, our proposal's primary implication is the simultaneous achievement of public service delivery that is efficient, effective, and defendable in the US constitutional democracy.
Partial Order Reduction for Model Checking of Timed Automata

The paper presents a partial order reduction method applicable to networks of timed automata. The advantage of the method is that it reduces both the number of explored control states and the number of generated time zones. The approach is based on a local-time semantics for networks of timed automata defined by Bengtsson et al. [1998], and used originally for local reachability analysis. In this semantics, each component automaton executes asynchronously, in its own local time scale, which is tracked by an auxiliary reference clock. On communication transitions, the automata synchronize their time scales. We show how this model can be used to perform model checking for an extension of linear temporal logic, which can express timing relations between events. We also show how for a class of timed automata, the local-time model can be implemented using difference bound matrices without any space penalty, despite the need to represent local time. Furthermore, we analyze the dependence relation between transitions in the new model and give practical conditions for selecting a reduced set of transitions.
SAASM: Rockwell Collins' next generation GPS receiver design

Rockwell Collins has leveraged its position as a primary military Global Positioning System (GPS) supplier by developing a new, low cost version of the Selective Availability Anti-Spoofing Module (SAASM) for use in multiple applications. The Rockwell Collins SAASM has been designed as a common module that can be used to support all internal SAASM applications. Its architecture provides an advanced set of core functions while at the same time supporting easy integration into various applications. This paper presents the architecture, features, and status of the Rockwell Collins SAASM and describes three applications that incorporate this module, specifically, NavStrike/sup TM/, the small serial interface (SSI) receiver, and GPS Embedded Module (GEM) V/sup TM/. "NavStrike" is a very small, high A/J, high G, fast direct Y (DY), receiver specifically designed for precision guided munitions (PGM) applications. Through the use of a proprietary technique, this receiver provides unclassified GPS measurement data for use in tightly coupled integrations. Position, velocity and time (PVT) outputs are also available. NavStrike uses special features such as a high-speed serial interface, a unique frequency standard and a clock calibration mode to perform fast DY acquisitions after up to 20 years of storage. A SSI product is being developed using the common SAASM module. Among the users of this GPS technology are the ground (low dynamics, minimal environmental) applications that embed the GPS directly within their own equipment. The PVT data provided by the SSI receiver can be easily integrated with the host system providing additional navigation performance with minimal space and cost impact. This SSI module, which uses the new GPS receiver applications module (GRAM) SSI standard, is being designed to be a seamless drop in replacement of existing ground applications embedded receivers. GEM V is the most recent member of the GEM product line. The GEM receivers are designed for high performance, high dynamic embedded applications. GEM V is a SAASM-based module that features the high A/J characteristics and direct Y capabilities of previous GEM products. The GEM V/sup TM/ is integrated with a host system through a dual port RAM or a serial port (RS-422) interface. Once integrated, the GEM can perform as a fully functional guidance system, as a PVT engine, or as a GPS measurement sensor.
Must Improved Labor Standards Hurt Accumulation in the Targeted Sector? Stylized Analysis of a Developing Economy

Abstract This paper analyzes a stylized small open economy that consists of two tradable output-producing sectors: a manufacturing sector and a (mainly tourism-related) services sector. Assuming sectoral differences based on stylized facts, we explore the impact of higher labor standards in the manufacturing sector on the long-term prospects of the economy using comparative dynamic exercises to analyze changes in relative prices, foreign capital flows, and the sectoral distribution of investment and output. We find, in particular, that imposing higher standards across the manufacturing sector could, under certain conditions, shift the structure of the domestic economy in favor of that sector. This result is driven by changes in relative profitability in the presence of learning-by-exporting.
Structure, Context and Replication in a Spatial-Temporal Architecture

This paper examines some general aspects of partitioning software architecture and the structuring of complex computing systems. It relates these topics in terms of the continued development of a generalized processing model for spatial-temporal processing. Data partitioning across several copies of a generic processing stack is used to implement horizontal scaling by reducing search space and enabling parallel processing. Temporal partitioning is used to provide fast response to certain types of queries and in quickly establishing initial context when using the system.
Groupes fondamentaux motiviques de Tate mixte

Resume Nous definissons la categorie des motifs de Tate mixte sur l'anneau des S-entiers d'un corps de nombres, et le groupe fondamental motivique (rendu unipotent) d'une variete unirationnelle sur un corps de nombres. Nous considerons plus en detail le groupe fondamental motivique de la droite projective moins 0, ∞ et les racines N-iemes de l'unite.
A SUBSTANTIAL DUST DISK SURROUNDING AN ACTIVELY ACCRETING FIRST-ASCENT GIANT STAR

We report identification of the first unambiguous example of what appears to be a new class of first-ascent giant stars that are actively accreting gas and dust and that are surrounded by substantial dusty disks. These old stars, who are nearing the end of their lives, are experiencing a rebirth into characteristics typically associated with newborn stars. The F2-type first-ascent giant star TYC 4144 329 2 is in a wide separation binary system with an otherwise normal G8 IV star, TYC 4144 329 1. From Keck near-infrared imaging and high-resolution spectroscopy, we are able to determine that these two stars are ~1 Gyr old and reside at a distance of ~550 pc. One possible explanation for the origin of the accreting material is common-envelope interaction with a low-mass stellar or substellar companion. The gaseous and dusty material around TYC 4144 329 2, as it is similar to the primordial disks observed around young classical T Tauri stars, could potentially give rise to a new generation of planets and/or planetesimals.
On one-dimensional digamma and polygamma series related to the evaluation of Feynman diagrams

We consider summations over digamma and polygamma functions, often with summands of the form (+/-1)^n@j(n+p/q)/n^r and (+/-1)^n@j^(^m^)(n+p/q)/n^r, where m, p, q, and r are positive integers. We develop novel general integral representations and present explicit examples. Special cases of the sums reduce to known linear Euler sums. The sums of interest find application in quantum field theory, including evaluation of Feynman amplitudes.
Simulating a class of stationary Gaussian processes using the Davies-Harte algorithm, with application to long memory processes

We demonstrate that the fast and exact Davies–Harte algorithm is valid for simulating a certain class of stationary Gaussian processes – those with a negative autocovariance sequence for all non-zero lags. The result applies to well known classes of long memory processes: Gaussian fractionally differenced (FD) processes, fractional Gaussian noise (fGn) and the nonstationary fractional Brownian Motion (fBm).
An Appearance-Based Particle Filter for Visual Tracking in Smart Rooms

This paper presents a visual particle filter for tracking a variable number of humans interacting in indoor environments, using multiple cameras. It is built upon a 3-dimensional, descriptive appearance model which features (i) a 3D shape model assembled from simple body part elements and (ii) a fast while still reliable rendering procedure developed on a key view basis of previously acquired body part color histograms. A likelihood function is derived which, embedded in an occlusion-robust multibody tracker, allows for robust and ID persistent 3D tracking in cluttered environments. We describe both model rendering and target detection procedures in detail, and report a quantitative evaluation of the approach on the `CLEAR'07 3D Person Tracking' corpus.
Comovement as an Investment Tool

A new tool for discovering mispriced securities is based on an analysis of comovement in asset prices. Recent research demonstrates that comovement can be due to both the trading patterns of noise traders and underlying economic fundamentals. As comovement can be measured much more accurately than expected returns, it can be used to identify securities for which the influence of noise traders is high and thus the securities most likely subject to mispricing. Analysis of comovement is a screening device that can provide important information about potential mispricing.