cssi/SciSciGPT-SciSciNet huggingface dataset:
The Number of Halving Circles

For the rest of sections 1 and 2, n is a fixed positive integer and S signifies an arbitrary set of 2n + 1 points in general position in the plane. There are several solutions to Problem 1. One possible approach is the following. Let A and B be two consecutive vertices of the convex hull of S. We claim that some circle going through A and B is halving. All circles through A and B have their centers on the perpendicular bisector e of the segment A B. Pick a point O on f that lies on the same side of A B as S and is sufficiently far away from A B that the circle F with center O and passing through A and B completely contains S. This can clearly be done. Now slowly "push" O along e, moving it towards AB. The circle F changes continuously with O. As we do this, F stops containing some points of S. In fact, it loses the points of S one at a time: if it lost P and Q simultaneously, then points P, Q, A, and B would be concyclic. We can move O sufficiently far away past AB that, in the end, the circle does not contain any points of S. Originally, F contained all the points of S. Now, as it loses one point of S at a time in this process, we can decide how many points we want it to contain. In particular, if we stop moving O when the circle is about to lose the nth point P of S, then the
The evolution of shareholder voting for executive compensation schemes

We examine shareholder voting on management-sponsored compensation proposals from 1992 through 2003 to determine how voting has evolved as a result of changes in the corporate governance environment. We investigate three questions: have regulatory changes and changes in investor sentiment affected voting; do the same factors appear to influence voting over time and has the impact of the various factors changed over time; and do additional factors such as the level of compensation and alternate definitions of dilution influence voting support? We find evidence of changing trends in voting, that shareholders have become more sensitive to potentially harmful plan provisions, and that additional factors do affect voting. D 2005 Elsevier B.V. All rights reserved.
Cosmic Variance and Its Effect on the Luminosity Function Determination in Deep High-z Surveys

We study cosmic variance in deep high-redshift surveys and its influence on the determination of the luminosity function for high-redshift galaxies. For several survey geometries relevant for Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) instruments, we characterize the distribution of the galaxy number counts. This is obtained by means of analytic estimates via the two-point correlation function in extended Press-Schechter theory, as well as by using synthetic catalogs extracted from N-body cosmological simulations of structure formation. We adopt a simple luminosity-dark halo mass relation to investigate the effects of environment on the fitting of the luminosity function. We show that in addition to variations of the normalization of the luminosity function, a steepening of its slope is also expected in underdense fields, similar to what is observed within voids in the local universe. Therefore, to avoid introducing artificial biases, caution must be taken when attempting to correct for field underdensity, such as in the case of the HST UDF i-dropout sample, which exhibits a deficit of bright counts with respect to the average counts in GOODS. A public version of the cosmic variance calculator based on the two-point correlation function integration is available on the Web at STScI.
Fine-scale partitioning of contemporary strain in the southern Walker Lane: Implications for accommodating divergent strike-slip motion

Treating the crust as a micropolar continuum and inverse modeling a high-quality catalog of earthquake focal mechanisms reveals that >km-scale heterogeneous strain is partitioned at ∼km-scales into pairs of plane strains with sub-perpendicular principal axes. These earthquakes occurred in a shallow crustal volume centered on the western Indian Wells Valley of eastern California, the site of divergent, right-lateral strike-slip motion along the boundary between the Sierran microplate and the southern Basin and Range province. The seismic events defining the plane strains occur in a diffuse seismic source zone and cannot be additionally subdivided on the basis of the type of strain they accommodate. The results indicate that seismic moment release for background earthquakes is partitioned into events associated with either fault-zone-perpendicular extension by normal faults or horizontal shearing by conjugate strike-slip faults. The spatial scales over which this partitioning occurs suggest that outcrop-scale brittle faults may in some cases record nearly perpendicular plane strains related to a single continuous deformation.
A Free Boundary Problem Inspired by a Conjecture of De Giorgi

We study global monotone solutions of the free boundary problem that arises from minimizing the energy functional , where V(u) is the characteristic function of the interval (−1, 1). This functiona...
FACILE SYNTHESIS OF SATURATED EIGHT-MEMBERED RING LACTONES

The synthesis of functionalized saturated eight-membered ring lactones from their corresponding seco acids is a very facile process using conventional macrolactonization protocols. This heretofore unrecognized and overlooked strategy is illustrated for several examples. A possible explanation for the success of this approach is also presented.
A coding approach to guarantee information integrity against a Byzantine relay

This paper presents a random coding scheme with which two nodes can exchange information with guaranteed integrity over a two-way Byzantine relay. This coding scheme is employed to obtain an inner bound on the capacity region with information integrity. No pre-shared secret or secret transmission is needed for the proposed scheme. Hence the inner bound obtained is generally larger than those achieved based on secret transmission schemes. This approach advocates the separation of supporting information integrity and secrecy.
The influence of an advecting vortex on the heat transfer to a liquid droplet

Abstract The unsteady three-dimensional interaction of an initially cylindrical vortex tube with a droplet in a uniform stream is investigated through a numerical solution of the Navier-Stokes equations. Particular attention is given to the effect of the vortex on the droplet convective heat transfer. The transient response of the droplet Nusselt number is sensitive to the geometrical factors that specify the vortex initial position and structure. The time-averaged Nusselt number is approximately the value for the axisymmetric case when the vortex center approaches the droplet along the base flow symmetry axis; otherwise, it varies monotonically with the vortex initial distance from the base flow symmetry axis, vortex circulation, and base flow Reynolds number. Beyond a certain range, the time-averaged Nusselt number reaches an asymptotic value. A correlation quantifying average effects of the vortex advection on the droplet heating, signifying a self-similar pattern in this unsteady problem, has been produced, and is shown to be also applicable to a rigid sphere in a comparable condition. This correlation compliments the existing ones for droplet healing in an axisymmetric flow. Based on these findings, it may be speculated that, in a spray combustion system, the vortex-droplet interactions within the Kolmogorov scale can have significant effects on the droplet convective heat transfer.
Shock interference prediction using direct simulation Monte Carlo

The shock interaction produced when an incident shock impinges on an inlet cowl lip is investigated for a cowl lip radius of 0.1 in. and flight conditions of Mach 15 and 35-km altitude. This problem is of interest in the design of hypersonic flight vehicles because the interference heating at the cowl lip surface from such a shock interaction is expected to be very high and the design of adequate thermal protection in this region will be challenging. Noncontinuum effects may be significant at this combination of altitude and small dimensions. If this is so, a computational solution based on the Navier-Stokes equations could significantly overpredict the surface heating on the cowl lip. Therefore, a kinetic theory solution technique, direct simulation Monte Carlo (DSMC), is used to predict the flowfield and surface heating. The details of modeling this problem and some preliminary results are presented. The same qualitative flow patterns are seen with DSMC and a continuum solution of the shock interference case, but the peak heating predicted with DSMC is somewhat lower.
Electronic and redox properties of stacked-ring silicon phthalocyanines from molecular orbital theory

Abstract : It is shown that the multi-peaked cyclic voltammograms for silicon phthalocyanine monomer-oligomer sets may be predicted from initial state molecular orbital energy levels if field shifts are used to allow for the charges of the anions and cations. The theory should have broad application for the understanding of the redox properties of other cofacial macrocyclic ring systems and the conductivity of doped cofacial polymers. The molecular orbital energy levels also produce the features of the optical and photoemission spectra of silicon phthalocyanine monomer-oligomer sets in the HOMO-LUMO energy regions, showing the importance of direct pi overlap.
First isolated active titanium peroxo complex: characterization and theoretical study.

monomeric Keggin type structure of 1 bearing one peroxo ligand attached to Ti(IV) in a 2 -coordination mode. The protonation of the titanium peroxo complex results in an increase of the redox potential of the peroxo group, E1/2 ) 1.25 and 0.88 V relative to Ag/AgCl reference electrode for 1 and 2, respectively. In contrast to 2, 1 readily reacts with 2,3,6-trimethylphenol (TMP) at 40 °C in MeCN to give 2,2′,3,3′,5,5′-hexamethyl-4,4′-biphenol (BP) and 2,3,5-trimethyl-p-benzoquinone (TMBQ). The proportion between BP and TMBQ in the reaction products depends on the TMP/1 ratio. When a 2-fold excess of TMP is used, the main reaction product is BP (90%), while using a 2-fold excess of 1 leads to TMBQ (95%). On the basis of the product study, a homolytic oxidation mechanism that implicates the formation of phenoxyl radicals is suggested. The RR deuterium labeling experiments show that the activating proton is most likely localized at a Ti-O-W bridging oxygen rather than at the peroxo group. Theoretical calculations carried out at the DFT level on the protonated and unprotonated titanium peroxo derivatives also propose that the most stable complex is formed preferentially after protonation of the Ti-O-W site; however, both Ti-OH-W and TiOO-H protonated anions could coexist in solution.
The Hecke Bicategory

We present an application of the program of groupoidification leading up to a sketch of a categorification of the Hecke algebroid—the category of permutation representations of a finite group. As an immediate consequence, we obtain a categorification of the Hecke algebra. We suggest an explicit connection to new higher isomorphisms arising from incidence geometries, which are solutions of the Zamolodchikov tetrahedron equation. This paper is expository in style and is meant as a companion to Higher Dimensional Algebra VII: Groupoidification and an exploration of structures arising in the work in progress, Higher Dimensional Algebra VIII: The Hecke Bicategory, which introduces the Hecke bicategory in detail.
Stall transients of axial compression systems with inlet distortion

A previously derived system of differential equations, based on fluid mechanics, is extended to provide a theory to predict how rotating stall or surge will develop in an axial compression system under combined influences of inlet distortion and throttle ramping. Results are relevant to the problem of stagnation stall of gas turbines. It is found that stall margin is improved by large aerodynamic lag in the compressor. Both stall and recovery transients are considered. A distinction between axisymmetric and in-rotating-stall compressor performance characteristics leads to a concept of rotating-stall stability that explains the appearance of classic stall at low stage loading and the hysteresis associated with rotating stall. The influences of various system parameters are systematically explored, and the large B parameter, tall compressor characteristic diagram, and rapid throttle closure are all found to favor surge, while large distortion and small shut-off head relative to peak pressure rise both favor rotating stall. When surge occurs, rotating stall is usually also present.
Artifact evaluation for software conferences

Software and other digital artifacts are amongst the most valuable contributions of computer science. Yet our conferences treat these mostly as second-class artifacts--especially conferences in the software sciences, which ought to know better. This article argues for elevating these other artifacts by making them part of the evaluation process for papers, and reports on experience from an iteration of an Artifact Evaluation Committee for ESEC/FSE 2011.
Chern-Simons solitons, chiral model, and (affine) Toda model on noncommutative space

We consider the Dunne-Jackiw-Pi-Trugenberger model of a U(N) Chern-Simons gauge theory coupled to a nonrelativistic complex adjoint matter on noncommutative space. Soliton configurations of this model are related the solutions of the chiral model on noncommutative plane. A generalized Uhlenbeck's uniton method for the chiral model on noncommutative space provides explicit Chern-Simons solitons. Fundamental solitons in the U(1) gauge theory are shaped as rings of charge and spin − where the Chern-Simons level should be an integer upon quantization. Toda and Liouville models are generalized to noncommutative plane and the solutions are provided by the uniton method. We also define affine Toda and sine-Gordon models on noncommutative plane. Finally the first order moduli space dynamics of Chern-Simons solitons is shown to be trivial.
Moisture and Temperature Effects on the Instability of Cylindrical Composite Panels.

Abstract : An analytical investigation was performed to evaluate the influences of moisture and temperature on the bifurcation load of cylindrical, composite panels subject to axial loading. The composite panels were 8-ply graphite/epoxy (AS/3501-5) laminates. The laminate ply orientations considered were (0., 45., -45., 90.) S, (90., 45., -45., 0.) S, and (45., -45.) 2S. The analysis included several different panel radii, two sets of boundary conditions, and three sets of initial moisture conditions. To evaluate the influences of moisture and temperature, the transverse moduli, E2, and shear moduli, G12, were degraded based on test data for the AS/3501-5 system. Each ply orientation was evaluated at 20 time/temperature conditions that ranged from 80 F to 300 F and moisture concentrations ranging from zero moisture content to an equilibrium moisture concentration distribution. The bifurcation loads were determined using the STAGS-C1 finite element shell analysis program. The bifurcation analysis mode with a pre-buckled linear displacement option was used for the analysis. Moisture and temperature were found to cause a reduction in the panels' bifurcation load ranging from 20.6 percent for the (0., 45., -45., 90.)S laminate to 42.7 percent for the (45., -45.) 2S laminate. (Author)
Cooling atoms with a moving one-way barrier

We demonstrate the use of a moving optical one-way barrier for cooling a collection of atoms, and how sensitive this method is to varying experimental parameters.
Teacher Incentives and Student Achievement: Evidence from New York City Public Schools

As global policy makers and school leaders look for ways to improve student performance, financial incentives programs for teachers have become increasingly popular. This article describes a school-based randomized trial in over 200 New York City public schools designed to better understand the impact of teacher incentives. I find no evidence that teacher incentives increase student performance, attendance, or graduation, nor do I find evidence that these incentives change student or teacher behavior. If anything, teacher incentives may decrease student achievement, especially in larger schools. The article concludes with a speculative discussion of theories to explain these stark results.
Optical Properties of Particulates

Optical properties of small particles of olivine (less than 0.1 μ) have been studied in the ultraviolet as an example of an insulating solid. Very little structure survives in the ultraviolet extinction curves for such small particles. By contrast ‘surface modes’, observed for graphite small particles in the ultraviolet and for olivine particles in the infrared, produce dominant and persistent structure in extinction. The general trend of optical properties of graphite is surprisingly similar to the behavior required to explain all features of the interstellar extinction and albedo curves from near visible to 1000 A. Measured extinction of small olivine particles in the infrared agrees with calculations based on newly measured optical constants, but dominant sharp structure in the 10μ region still presents a bit of a problem in explaining ‘silicate’ features in astronomical data.
The flying radiation case

Summary form only given, as follows. The Los Alamos foil implosion program has the goal of producing an intense high-energy density X-ray source by converting the energy of a magnetically imploded plasma into radiation and material energy. One of the methods for converting the kinetic energy of the plasma into thermal energy and radiation and utilizing it for experiments is called the "flying radiation case (FRC)." In this paper we shall model the FRC and provide a physical description of the processes involved.
High-repetition-rate continuously pumped ruby laser

The first successful operation of a high-repetition-rate repetitively Q -switched ruby laser is reported. Using an acousto-optic Q switch, repetition rates up to 5000 pps have been achieved. When the laser is optimized, peak power outputs of 20 kW at 500 pps and 8 kW at 2000 pps can be expected.
Directional multiscale statistical modeling of images

The contourlet transform is a new extension to the wavelet transform in two dimensions using non-separable and directional filter banks. The contourlet expansion is composed of basis images oriented at varying directions in multiple scales, with flexible aspect ratios. With this rich set of basis images, the contourlet transform can effectively capture the smooth contours that are the dominant features in natural images with only a small number of coefficients. We begin with a detail study of the statistics of the contourlet coefficients of natural images, using histogram estimates of the marginal and joint distributions, and mutual information measurements to characterize the dependencies between coefficients. The study reveals the non-Gaussian marginal statistics and strong intra-subband, cross-scale, and cross-orientation dependencies of contourlet coefficients. It is also found that conditioned on the magnitudes of their generalized neighborhood coefficients, contourlet coefficients can approximately be modeled as Gaussian variables with variances directly related to the generalized neighborhood magnitudes. Based on these statistics, we model contourlet coefficients using a hidden Markov tree (HMT) model that can capture all of their inter-scale, inter-orientation, and intra-subband dependencies. We experiment this model in the image denoising and texture retrieval applications where the results are very promising. In denoising, contourlet HMT outperforms wavelet HMT and other classical methods in terms of both peak signal-to-noise ratio (PSNR) and visual quality. In particular, it preserves edges and oriented features better than other existing methods. In texture retrieval, it shows improvements in performance over wavelet methods for various oriented textures.
New Synchronous Orbits Using the Geomagnetic Lorentz Force

The Lorentz-augmented orbits concept provides propellantless electromagnetic propulsion without a tether, using the interaction between an electrostatically charged satellite and the Earth's magnetic field to provide a useful thrust. New types of Earth-synchronous orbits are found from equations governing the motion of satellites experiencing the Lorentz force in orbit. The equations of motion for such a spacecraft are derived based on a simplified magnetic field model, in which the dipole is aligned with true north. For a polar-orbiting satellite, a constant electrical charge can create arbitrary changes in the right-ascension angle. This method allows for single-orbit repeat-groundtrack low-Earth-orbit satellites. Analytical expressions for changes in orbital elements due to Lorentz forces are verified by numerical simulation for the polar and equatorial cases. In the equatorial case, manipulation of the longitude of perigee by constant electrostatic charge is possible. Perigee movement also allows for the creation of an Earth-synchronous type of orbit. The case of a dipole field, for which the north pole is not aligned with true north, is also examined. Feedback control using only the Lorentz force for actuation is shown to stabilize this general case.
Securities Trading in the Absence of Dealers: Trades, and Quotes on the Tokyo Stock Exchange

Yasushi HamaoColumbia UniversityJoel HasbrouckNew York UniversityThis article investigates the behavior of intra-day trades and quotes for individual stocks onthe Tokyo Stock Exchange (TSE). We examine thetransaction and quote record for three firms forthe first 3 months of 1990. Our findings suggestthat the immediacy available (at least for smalltrades) in the market is high, despite the re-liance on public limit orders to supply liquidity.When orders that would otherwise walk throughthe limit order book are converted into limit or-ders, execution is delayed; but some orders exe-cute (at least in part) at more favorable prices.
Application of the Vortex-Lattice Technique to Arbitrary Bodies

A numerical technique that predicts the potential flowfield past arbitrary bodies is presented. To epresent the body surface, the technique utilizes a combination of a vortex lattice and sources. The vortex-lattice is formed by constant-strength quadrilateral, as well as triangular, elements. The technique features the minimum selfinduced-velocity control point, which was found to be the best choice, and uses the element loop circulations as the unknowns while working with predetermined surface-source strengths. For blunt bodies, the combination of a vortex lattice and sources appears to be superior to either the votex lattice or the sources acting alone. For slender bodies, the combination offers no apparent advantage over the vortex lattice alone, and the vortex lattice appears to be superior to the sources. This technique was tested by comparing the predicted pressures with exact solutions and experimental data. The present method can reliably and accurately treat flows past arbitrary bodies.
Fine-Scale Turbulence Noise from Dual-Stream Jets

Nowadays, commercial aircrafts, invariably, use high-bypass-ratio dual-stream jets for propulsion. As yet, there is still an urgent need for an accurate physics-based noise prediction theory for jets of this configuration. Thus, an investigation is made to determine whether the Tam and Auriault theory, originally developed for predicting the fine-scale turbulence noise of single-stream jets, is capable of predicting accurately the fine-scale turbulence noise of dual-stream jets from separate flow nozzles operating at various bypass ratios. The configuration of a separate flow nozzle is fairly complex. Hence, the jet flow and turbulence in the nozzle region and in the region immediately downstream are also fairly complex. However, these are also the most important noise source regions of the jet. To enable an accurate computation of the mean flow and turbulence level in these regions, a computational aeroacoustics marching algorithm for calculating the parabolized Reynolds averaged Navier-Stokes equations supplemented by the k-e turbulence model is provided
Doppler ambiguity resolution using optimal multiple pulse repetition frequencies

Ferrari, Berenguer, and Alengrin (ibid., vol. 33, pp. 738-51, 1997) proposed an algorithm for velocity ambiguity resolution in coherent pulsed Doppler radar using multiple pulse repetition frequencies (PRFs). In this algorithm, two step estimations (folded frequency and ambiguity order) for the Doppler frequency is used by choosing particular PRF values. The folded frequency is the fractional part of the Doppler frequency and is estimated by averaging the folded frequency estimates for each PRF. The ambiguity order is the integer part of the Doppler frequency and is estimated by using the quasi-maximum-likelihood criterion. The PRF are grouped into pairs and each pair PRF values are symmetric about 1. The folded frequency estimate for each pair is the circular mean of the two folded frequency estimates of the pair due to the symmetry property. We propose a new algorithm based on the optimal choice of the PRF values, where the PRF values are also grouped into pairs. In each pair PRF values, one is given and the other is optimally chosen. The optimality is built upon the minimal sidelobes of the maximum likelihood criterion. Numerical simulations are presented to illustrate the improved performance.
Distributed space-time-coded protocols for exploiting cooperative diversity in wireless networks

We develop and analyze space-time coded cooperative diversity protocols for combating multipath fading across multiple protocol layers in a wireless network. The protocols exploit spatial diversity available among a collection of distributed terminals that relay messages for one another in such a manner that the destination terminal can average the fading, even though it is unknown a priori which terminals will be involved. In particular, a source initiates transmission to its destination, and many relays potentially receive the transmission. Those terminals that can fully decode the transmission utilize a space-time code to cooperatively relay to the destination. We demonstrate that these protocols achieve full spatial diversity in the number of cooperating terminals, not just the number of decoding relays, and can be used effectively for higher spectral efficiencies than repetition-based schemes. We discuss issues related to space-time code design for these protocols, emphasizing codes that readily allow for appealing distributed versions.
Tuning ground states and excitations in complex electronic materials

Modern electronic materials are characterized by a great variety of broken-symmetry ground states and excitations. Their control requires understanding and tuning underlying driving forces of spin-charge-lattice coupling, critical to macroscopic properties and applications. We report representative model calculations which demonstrate some of the richness of the phenomena and the challenges for successful microscopic modeling.
Small talk and cooperation: A note on bounded rationality

Abstract Neyman has shown that bounded rationality can lead to cooperation in the finitely repeated prisoner's dilemma game, if the game is conducted by finite automata of fixed size. We obtain similar results utilizing finite automata which can send messages back and forth over a given communication channel. The communication protocol utilized does not involve the transfer of any relevant information. Rather, it saturates the computational resources of the players thus preventing them from engaging in complex strategies which could potentially undermine cooperation.
Renal cell carcinoma metastatic to the pancreas: results of surgical management

Metastatic tumors to the pancreas are uncommon. Renal cell carcinoma is one of the few tumors known to metastasize to the pancreas. The purpose of the current report is to evaluate the surgical management and long-term outcome of patients with metastatic renal cell carcinoma. A retrospective review of patients undergoing pancreatic resection for renal cell carcinomas metastatic to the pancreas or periampullary region between April 1989 and May 1999, inclusive, was performed. Time from initial presentation, other metastatic sites, surgical outcomes, and long-term survival were evaluated. During the 10-year time period, 10 patients underwent pancreatic resection for renal cell carcinoma metastases. Of those, six underwent pancreaticoduodenectomy and two underwent distal pancreatectomy, whereas the two remaining patients underwent total pancreatectomy for extensive tumor involvement throughout the entire gland. The mean time from nephrectomy for resection of the primary tumor to reoperation for periampullary recurrence was 9.8 years (median 8.5 years). The range was 0 to 28 years, with one patient presenting with a synchronous metastasis. The mean age of the patients was 61.2 years with 60% of patients being male and 90% being white. Pathologic findings included histologically negative lymph nodes and negative surgical margins in all patients. One patient had tumor involving the retroperitoneal soft tissue, but final margins were negative. The mean live patient follow-up was 30 months (median = 15 months), with eight patients remaining alive. The Kaplan-Meier actuarial 5-year survival was 75%, with the longest survivor still alive 117 months following resection. The patient with retroperitoneal soft tissue involvement died 4 months after resection. The pancreas is an uncommon site of metastasis for renal cell carcinoma, typically occurring years after treatment of the primary tumor. When the metastatic focus is isolated and the tumor can be resected in its entirety, patients can experience excellent 5-year survival rates. The current report suggests that pancreatic metastases from renal cell carcinoma should be managed aggressively with complete resection when possible.
MEMS packaging and microassembly challenges

MEMS devices have evolved in the last 10 years from an academic and laboratory curiosity to a viable technology with potential widespread application. Significant advancements are now being made to package and manufacture MEMS devices for the commercial and consumer marketplace. In MEMS devices that are silicon-based, integrated circuit fabrication techniques are used to reduce the size of mechanical features to the miniature dimensions of microelectronics. Integrating these mechanical features with electronic circuits on the same chip offers a wealth of new product opportunities not possible with conventional design and manufacturing approaches. Initially MEMS referred to silicon-based devices but today refers to a complete miniature device that may or may not be silicon based. Also MEMS devices have expanded beyond the integration of electronic and mechanical functions. Today devices can have mechanical, optical, fluidic, and thermal functions in some combination with each other and generally integrated with electronic functions. MEMS technology can be used to fabricate extremely sensitive sensors for a variety of applications including pressure, sound, mass, motion, acceleration, rotation, flow, chemicals, vibration, and temperature. The technology can also be used to fabricate field-emission tips and probes for use in high-brightness specialized displays, electron-beam sources, information storage applications and precision temperature sensing. Actuators can be fabricated for use in optical switching, flow control, micropositioning, adaptive optics, and displays. Finally, a variety of passive, three-dimensional, micromechanical structures can be fabricated with applications in telecommunications, electronic components, and sensors.
The LEMMA concept: A new manipulator

Abstract The LEMMA is a proposed conceptual design of a remote teleoperator manipulator arm with 6 degrees of freedom, exclusive of the end-effector. The bevel gear arrangement in 4 of the 6 degrees of freedom, together with the concentric-tubular arm configuration, requires a unique and a novel drive mechanism. This differential drive assembly, housed in the shoulder, is a self-compensating device and simplifies the matrix solution for the resolved motion rate control system needed to guide the arm in its performances. The article will describe the need for the 6 degrees of freedom as established by the work envelope, the functioning of the differential shoulder drive, the arm and joint configuration, and the anticipated degree of accuracy.
Structure of supergiant shells in the large magellanic cloud

Nine supergiant shells (SGSs) have been identified in the Large Magellanic Cloud (LMC) based on Hα images, and 23 SGSs have been reported based on H I 21 cm line observations, but these sets do not always identify the same structures. We have examined the physical structure of the optically identified SGSs using H I channel maps and P-V diagrams to analyze the gas kinematics. There is good evidence for seven of the nine optically identified SGSs to be true shells. Of these seven Hα SGSs, four are the ionized inner walls of H I SGSs, while three are an ionized portion of a larger and more complex H I structure. All of the Hα SGSs are identified as such because they have OB associations along the periphery or in the center, with younger OB associations more often found along the periphery. After roughly 12 Myr, if no new OB associations have been formed, a SGS will cease to be identifiable at visible wavelengths. Thus, the presence and location of ionizing sources is the main distinction between shells seen only in H I and those also seen in Hα. Based on our analysis, Hα observations alone cannot unambiguously identify SGSs, especially in distant galaxies.
On Justifying Democracy

Part 1: Decisions and Procedures Part 2: Procedural Fairness and Equality 1. Majority Rule and Fairness 2. Procedural Fairness and Justification 3. Possible Replies and Further Considerations Conclusions Part 3: Participation 1. Background: Schumpeter and the Revisionists 2. Participation Theory 3. Problems and Questions 4. Self Government, Consent and Authorization 5. Equal Rights to Participate 6. Participation and Virtue Conclusions Part 4: Popular Sovereignty 1. Arrow's Theorem 2. The Relevance of Arrow's Theorem 3. An Alternative Approach 4. Why Popular Sovereignty? 5. Some Consequences Part 5: Economic Theories 1. An Example of Economic Analysis: The Intensity Problem 2. Buchanan and Tullock's Rationale for Democracy 3. Internal Criticism 4. External Criticism Part 6: Open Government and Just Legislation: A Defense of Democracy 1. Dahl on Madison 2. Morality and Just Government 3. A Conception of Morality 4. Democracy and Just Government: Mill's Argument 5. Summary, Objections and Qualifications 6. Comparisons and Contrasts Part 7: Law and Morality: The Problem of Political Obligation 1. Law and Morality 2. An Act Utilitarian View 3. The Content of Morality and the Interpretation of Law 4. Secondary Principles of Obligation
International term structures and real economic growth

Abstract This paper extends previous work on the information in the term structure about future real economic growth. For the U.S. and Germany, and to a lesser extent for the U.K., we find evidence that the long end of the term structure has information about future growth of industrial production beyond expectations about future monetary policy. We also find evidence that foreign term structures can forecast domestic low frequency movements in economic activity especially in countries that experience high and variable rates of inflation.
Advances in Supersonic Configuration Design Methods

A linearized panel method program developed for the design and analysis of wing-body configurations at supersonic speeds (Woodward 1) has been modified to permit the user to specify the loading for an arbitrary region of the wing. The remaining portion of the wing is then optimized on the basis of the prescribed loading. This insures that the final shape will produce the minimum drag possible within the constraints. In addition, the design feature has been incorporated into an improved panel method supersonic analysis program (Woodward II). Since this code has the capability of representing bodies of noncircular cross section, it is expected to prove useful in the design of aircraft configurations with arbitrarily shaped fuselages. Comparisons are presented with other known minimum drag solutions which demonstrate the validity of both new techniques.
Deciding Combinations of Theories

A method is given for deciding formulas in combinations of unquatified first-order theories. Rather than coupling separate decision procedures for the contributing theories, it makes use of a single, uniform procedure that minimizes the code needed to accommodate each additional theory. The method is applicable to theories whose semantics can be encoded within a certain class of purely equational canonical form theories that is closed under combination. Examples are given from the equational theories of integer and real arithmetic, a subtheory of monadic set theory, the theory of cons, car, and cdr, and others. A discussion of the speed performance of the procedure and a proof of the theorem that underlies its completeness are also given. The procedure has been used extensively as the deductive core of a system for program specification and verification.
Stellar Dynamics at the Galactic Center with an Extremely Large Telescope

We discuss physical experiments achievable via the monitoring of stellar dynamics near the massive black hole at the Galactic center with a diffraction-limited, next-generation, extremely large telescope (ELT). Given the likely observational capabilities of an ELT and what is currently known about the stellar environment at the Galactic center, we synthesize plausible samples of stellar orbits around the black hole. We use the Markov Chain Monte Carlo method to evaluate the constraints that the monitoring of these orbits will place on the matter content within the dynamical sphere of influence of the black hole. We express our results as functions of the number N of stars with detectable orbital motions and the astrometric precision δθ and spectroscopic precision δv at which the stellar proper motions and radial velocities are monitored. Our results are easily scaled to different telescope sizes and precisions. For N = 100, δθ = 0.5 mas, and δv = 10 km s-1 (a conservative estimate of the capabilities of a 30 m telescope) we find that if the extended matter distribution enclosed by the orbits at 0.01 pc has a mass greater than ~103 M☉, it will produce measurable deviations from Keplerian motion. Thus, if the concentration of dark matter at the Galactic center matches theoretical predictions, its influence on the orbits will be detectable. We also estimate the constraints that will be placed on the mass of the black hole and on the distance to the Galactic center and find that both will be measured to better than ~0.1%. We discuss the significance of knowing the distance to within a few parsecs and the importance of this parameter for understanding the structure of the Galaxy. We demonstrate that the lowest order relativistic effects, such as the prograde precession, will be detectable if δθ 0.5 mas. Barring the favorable discovery of a star on a highly compact, eccentric orbit, the higher order effects, including the frame dragging due to the spin of the black hole, will require δθ 0.05 mas. Finally, we calculate the rate at which monitored stars experience detectable nearby encounters with background stars. The encounters probe the mass function of stellar remnants that accumulate near the black hole. We find that ~30 such encounters will be detected over a 10 yr baseline for δθ = 0.5 mas.
Uniqueness of Low-Rank Matrix Completion by Rigidity Theory

The problem of completing a low-rank matrix from a subset of its entries is often encountered in the analysis of incomplete data sets exhibiting an underlying factor model with applications in collaborative filtering, computer vision, and control. Most recent work has been focused on constructing efficient algorithms for exact or approximate recovery of the missing matrix entries and proving lower bounds for the number of known entries that guarantee a successful recovery with high probability. A related problem from both the mathematical and algorithmic points of view is the distance geometry problem of realizing points in a Euclidean space from a given subset of their pairwise distances. Rigidity theory answers basic questions regarding the uniqueness of the realization satisfying a given partial set of distances. We observe that basic ideas and tools of rigidity theory can be adapted to determine uniqueness of low-rank matrix completion, where inner products play the role that distances play in rigidity theory. This observation leads to efficient randomized algorithms for testing necessary and sufficient conditions for local completion and for testing sufficient conditions for global completion. Crucial to our analysis is a new matrix, which we call the completion matrix, that serves as the analogue of the rigidity matrix.
Poly(silylenemethylenes) — a novel class of organosilicon polymers

Abstract The synthesis and investigation of the poly(silylenemethylene)s, linear polymers with a regular -RR'SiCH2- repeat unit, are reviewed, particularly from the standpoint of recent work carried out in the authors' own laboratory in the past few years. Improvement in the synthetic routes to the substituted disilacyclobutanes used as monomers in the ring-opening polymerization process employed for the synthesis of these polymers has enabled the preparation of a wide range of new polymers of this type. This range of polymers has been extended further by using reactive functionalities on Si in polymers containing Si-Cl, Si-OR and Si-H groups to append various side chains on to the polymer backbone. The parent polymer in this series, polysilaethylene, has been studied as an analog of polyethylene and as a precursor for silicon carbide, leading to information about the crystalline structure for the solid form of this polymer, as well as on the polymer-to-ceramic conversion process. The ethoxy-substituted polymer, [Si(OEt)2CH2]n, undergoes hydrolysis and condensation on treatment with water to produce a gel which has an inorganic (Si-O-Si)/organic (Si-CH2-Si) network structure. Upon pyrolysis to 1000°C, this gel is converted into a silicon oxycarbide having a full distribution of SiC4−xOx (x - 0–4) microenvironments.
A New Route to Acyclic Diaminocarbenes via Lithium−Halogen Exchange

A lithium−halogen exchange route has been developed to generate acyclic diaminocarbenes (ADC) from chloroamidinium salts. Convenient access to various ADC complexes (B, Rh, Ir, Pd) stems from a one-pot transmetalation protocol. Formation of a carbenoid species is suggested by 1D and 2D NMR studies with a 13C-labeled chloroamidinium precursor and also by X-ray structures of transition metal−carbene complexes. Rh-ADC complex 4 is an effective catalyst for the 1,2-addition of aryl boronic acids to aryl aldehydes.
Cilk: An Efficient Multithreaded Runtime System

Abstract Cilk (pronounced “silk”) is a C-based runtime system for multithreaded parallel programming. In this paper, we document the efficiency of the Cilk work-stealing scheduler, both empirically and analytically. We show that on real and synthetic applications, the “work” and “critical-path length” of a Cilk computation can be used to model performance accurately. Consequently, a Cilk programmer can focus on reducing the computation's work and critical-path length, insulated from load balancing and other runtime scheduling issues. We also prove that for the class of “fully strict” (well-structured) programs, the Cilk scheduler achieves space, time, and communication bounds all within a constant factor of optimal. The Cilk runtime system currently runs on the Connection Machine CM5 MPP, the Intel Paragon MPP, the Sun Sparcstation SMP, and the Cilk-NOW network of workstations. Applications written in Cilk include protein folding, graphic rendering, backtrack search, and the ★Socrates chess program, which won second prize in the 1995 ICCA World Computer Chess Championship.
Exchange Rate Misalignments in Frequency Domain

This research uses spectral methodology to study how the volatility of spot exchange rate misalignments changed as a result of (1) signing of the Plaza Accord and (2) introduction of the Euro. We study the deviations of Canadian Dollar/US Dollar, Japanese Yen/US Dollar and US Dollar/British Pound spot exchange rates from CPI- and TPI-based equilibrium exchange rates. The spectral density results indicate that the Plaza Accord and the introduction of the Euro helped reduce the volatility of exchange rate misalignments and excess returns for the Yen and the Pound along virtually all frequency components. On the other hand, the Canadian Dollar/US Dollar misalignments are characterized by higher volatility after the adoption of the Plaza Accord.
Novel pyrrolo-quinoline derivatives as potent inhibitors for PI3-kinase related kinases.

Abstract Several pyrrolo-quinoline γ-lactones were found as novel inhibitors for two members of the PI3-kinase related kinase (PIKK) family, Ataxia-Telangiectasia-mutated (ATM) protein and the mammalian Target of Rapamycin (mTOR). Preliminary structure–activity relationship studies indicated that an electrophilic exocyclic double bond conjugated to the carbonyl group of the γ-lactone ring was crucial for the PIKK inhibitory potency. One of the best ATM inhibitors in this series, DK8G557, showed IC50 values of 0.6 and 7.0 μM for ATM and mTOR, respectively. This compound exhibited potent and selective growth inhibition activities in the NCI 60 human tumor cell line screen with a GI50 MG-MID value of 2.69 μM. The best mTOR inhibitor in this series, HP9912, exhibited IC50 values of 0.5 and 6.5 μM for mTOR and ATM, respectively. These compounds suggest novel leads for the discovery of potent small molecule inhibitors of PIKKs as potential anticancer drugs, with therapeutic activities as either single, or as sensitizing agents to conventional radio-, or chemo-therapeutic strategies.
Cosmic-Ray Rejection and Readout Efficiency for Large-Area Arrays

We present an algorithm to optimally process uniformly sampled array image data obtained with a nondestructive readout. The algorithm discards full wells, removes cosmic-ray (particle) hits and other glitches, and makes a nearly optimum estimate of the signal on each pixel. The algorithm also compresses the data. The computer requirements are modest, and the results are robust. The results are shown and compared to results of Fowler-sampled and -processed data. Nonideal detector performance may require some additional code, but this is not expected to cost much processing time. Known types of detector faults are addressed.