cssi/SciSciGPT-SciSciNet huggingface dataset:
Second Sourcing vs. Sole Sourcing with Capacity Investment and Asymmetric Information

We study the decision of a manufacturer (the buyer), expecting new sourcing opportunities in the future, in selecting between sole-and second-sourcing strategies for a noncommodity component. In a sole-sourcing strategy, the buyer commits to sourcing from a single supplier (the incumbent) over the entire horizon. In a second-sourcing strategy, the buyer keeps the option open to source from a new supplier (the entrant) in the future. Supplier costs are private information, and the incumbent's cost may change in the future because of what it has learned. The buyer is relatively sure about current demand but uncertain about future demand. A supplier has to invest in capacity to produce the inputs for the buyer. With future private cost information, the incumbent earns rent in the future, and this prospective rent influences the incumbent's decision early in the horizon. On one hand, a second-sourcing strategy allows the buyer to take advantage of alternative sourcing opportunities, lowering her future cost. This benefit to the buyer is referred to as the option value of second sourcing. On the other hand, the future supplier competition in second-sourcing hurts the incumbent's future profit. The expectation of a lower future profit in second sourcing induces the incumbent to ask for a higher price at the beginning of the horizon. This causes more initial sourcing cost for the buyer in second sourcing than in sole sourcing, and is referred to as the cost of future supplier competition of second sourcing. The overall benefit of second sourcing relative to sole sourcing is influenced by the demand distribution and capacity cost. If the demand increases over time with positive probability, the incumbent's initial capacity may not be able to cover all future demand. If the capacity is cheap, the entrant may serve as an exclusive supplier, ousting the incumbent. In this case, the option value of second sourcing is high. If the capacity is expensive, the entrant may serve as a supplementary supplier by receiving only the demand in excess of the incumbent's installed capacity. In this case, the cost of future supplier competition is low and the option value is still significant. Thus second sourcing is better than sole sourcing not only when the capacity cost is low, but also when it is high (under the condition that demand increases over time with positive probability and the entrant's cost is relatively low). For intermediate capacity cost, the cost of future supplier competition dominates the option value; hence, sole sourcing is preferred. We also find that second sourcing is more attractive when the buyer expects the future demand to be higher or more volatile. Finally, more initial incumbent capacity strengthens the incumbent's competitiveness against the entrant, reducing the cost of future supplier competition. As a result, we find that second sourcing may lead to overinvestment of the initial capacity.
Privacy considerations for a pervasive eye tracking world

Multiple vendors now provide relatively inexpensive desktop eye and gaze tracking devices. With miniature-ization and decreasing manufacturing costs, gaze trackers will follow the path of webcams, becoming ubiquitous and inviting many of the same privacy concerns. However, whereas the privacy loss from webcams may be obvious to the user, gaze tracking is more opaque and deserves special attention. In this paper, we review current research in gaze tracking and pupillometry and argue that gaze data should be protected by both policy and good data hygiene.
Preparation of 1-(tert-butoxycarbonyl)-2,6-dialkyl-2,3-dihydro-4-pyridones. A stereocontrolled synthesis of (±)-myrtine

Abstract A convenient preparation of N-BOC-2,6-dialkyl-2,3-dihydro-4-pyridones is described and utilized in a stereocontrolled synthesis of (±)-myrtine
Evolution of galaxies and its significance for cosmology

Possible effects on observational cosmology of star evolution in ordinary galaxies are described. Only Friedman models with zero cosmological constants are considered. Numerical models for elliptical galaxies are discussed. 46 references. (BJG)
Natural organic matter and the event horizon of mass spectrometry.

Soils, sediments, freshwaters, and marine waters contain natural organic matter (NOM), an exceedingly complex mixture of organic compounds that collectively exhibit a nearly continuous range of pro...
Competitive delivered pricing and production

Abstract This paper studies price and production competition between profit-maximizing firms that use delivered spatial prices. Firms produce an identical good and customers buy from the firm offering the least delivered price. Each firm's transportation cost is quantity dependent and customer's demands are price elastic. This contrasts with much of the literature on competitive spatial pricing that assumes inelastic customer demand and linear firm costs, and which ignores the firm's production problem. This paper makes three contributions. First,a game-theoretic model is defined and the existence of the delivered price and production equilibrium is proved. Second, properties of the equilibrium are shown including patterns of spatial pricing. Properties of pricing and production are different from the case when transportation costs are quantity independent. For example, more than one firm may serve a single market. Third, it is shown that in equilibrium, competing firms may optimally choose delivered mill prices and have incentive to locate coincidentally. This result can explain coincident location of mill pricing firms.
Strong-Coupling Superconductivity. I

The pairing theory of superconductivity is extended to treat systems having strong electron-phonon coupling. In this regime the Landau quasiparticle approximation is invalid. In the theory we treat phonon and Coulomb interactions on the same basis and carry out the analysis using the nonzero-temperature Green's functions of the Nambu formalism. The generalized energy-gap equation thus obtained is solved (at $T=0$ \ifmmode^\circ\else\textdegree\fi{}K) for a model which closely represents lead and the complex energy-gap parameter $\ensuremath{\Delta}(\ensuremath{\omega})$) is plotted as a function of energy for several choices of phonon and Coulomb interaction strengths. An expression for the single-particle tunneling density of states is derived, which, when combined with $\ensuremath{\Delta}(\ensuremath{\omega})$, gives excellent agreement with experiment, if the phonon interaction strength is chosen to give the observed energy gap ${\ensuremath{\Delta}}_{0}$ at zero temperature. The tunneling experiments therefore give a detailed justification of the phonon mechanism of superconductivity and of the validity of the strong-coupling theory. In addition, by combining theory and the tunneling experiments, much can be learned about the electron-phon interaction and the phonon density of states. The theory is accurate to terms of order the square root of the electron-ion mass ratio, ${\mathrm{\ensuremath{\sim}}10}^{\ensuremath{-}2}$-${10}^{\ensuremath{-}3}$.
On program development effort and productivity

Abstract Many claims are made in the literature concerning large productivity increases as a result of the introduction of various new programming tools and techniques. Seldom do the researchers substantiate these claims, however. Further, many of the reported studies have been unsuccessful because much of the existing research is methodologically flawed and poorly grounded in theory. This paper investigates the methodological problems of previous studies and reports the results of a field study conducted to assess the feasibility of conducting controlled studies of the programming process. A field study of COBOL programs from three commercial organizations investigated the effects of programming style (i.e., structured programming) and programmer skill on (i) the effort required to develop programs and (ii) programming productivity; program size was used as a control variable. The results of the study support the underlying concept: that use of disciplined approaches and well-defined variables leads to more readily interpretable and more conclusive results.
Taming Capital Flows

Abstract The argument of this paper is that growing capital mobility is unavoidable. Domestic financial liberalization and the revolution in information and communications technologies make it much more difficult to stop capital flows at the border. Effective controls will therefore have to become increasingly comprehensive, onerous, and distortionary. The issue is therefore how to cope with the reality of high capital mobility and to manage the transition. This means not freeing capital flows before substantial progress has been made in liberalizing domestic financial markets and strengthening financial supervision. It means liberalizing foreign direct investment first, access to stock and bond markets second, and offshore bank-funding last. It means putting in place exchange rate, monetary and fiscal policies that do not destabilize the capital account. It means reforming monetary and fiscal institutions to assure the markets of the capacity to deliver desirable monetary and fiscal outcomes.
Regioselective ketone α-alkylation with simple olefins via dual activation

Alkylation of carbonyl compounds is a commonly used carbon-carbon bond-forming reaction. However, the conventional enolate alkylation approach remains problematic due to lack of regioselectivity, risk of overalkylation, and the need for strongly basic conditions and expensive alkyl halide reagents. Here, we describe development of a ketone-alkylation strategy using simple olefins as the alkylating agents. This strategy employs a bifunctional catalyst comprising a secondary amine and a low-valent rhodium complex capable of activating ketones and olefins simultaneously. Both cyclic and acyclic ketones can be mono-α-alkylated with simple terminal olefins, such as ethylene, propylene, 1-hexene, and styrene, selectively at the less hindered site; a large number of functional groups are tolerated. The pH/redox neutral and byproduct-free nature of this dual-activation approach shows promise for large-scale syntheses.
P(i-BuNCH2CH2)3N: an efficient promoter for the nucleophilic aromatic substitution reaction of aryl fluorides with aryl TBDMS (or TMS) ethers.

The nucleophilic aromatic substitution reaction between electron-deficient aryl fluorides and aryl TBDMS (or TMS) ethers has been shown to be efficiently promoted by proazaphosphatranes such as P(i-BuNCH2CH2)3N (3). Excellent yields of diaryl ether products were obtained under unusually mild conditions.
Super Yang-Mills in (11,3) dimensions

Abstract A supersymmetric Yang-Mills system in (11, 3) dimensions is constructed with the aid of two mutually orthogonal null vectors which naturally arise in a generalized spacetime superalgebra. An obstacle encountered in an attempt to extend this result to beyond 14 dimensions is described. A null reduction of the (11, 3) model is shown to yield the known super Yang-Mills model in (10, 2) dimensions. An (8, 8) supersymmetric super Yang-Mills system in (3, 3) dimensions is obtained by an ordinary dimensional reduction of the (11, 3) model, and it is suggested there may exist a superbrane with (3, 3) dimensional worldvolume propagating in (11, 3) dimensions.
Physics at the light-front

Abstract The light-front representation of quantum chromodynamics provides a frame-independent, quantum-mechanical representation of hadrons at the amplitude level, capable of encoding their multi-quark, hidden-color and gluon momentum, helicity, and flavor correlations in the form of universal process-independent hadron wavefunctions. The universality and frame-independence of the light-cone wavefunctions thus allow a profound connection between diffractive dissociation, hard scattering exclusive processes such as elastic form factors, two-photon reactions, and heavy hadron decays. In this concluding talk of the ECT∗ International Conference On Light-Cone Physics: Particles And Strings (Trento 2001), I review recent calculations and new applications of light-front wavefunctions in QCD and other theories. I also review the distinction between the structure functions measured in deep inelastic lepton scattering and the quark distributions determined from light-front wavefunctions.
The Accuracy of Morphological Decomposition of Active Galactic Nucleus Host Galaxies

In order to assess the accuracy with which we can determine the morphologies of AGN host galaxies, we have simulated more than 50,000 ACS images of galaxies with z 1 : 4. We give quantitative estimates of parameter errors as a function of host-to-point-source ratio. In general, we separate host and point-source magnitudes reliably at all redshifts; point sources are well recovered more than 90% of the time, although spurious detection of central point sources can be as high as 25% for bulge-dominated sources. We find a general correlation between Sersic index and intrinsic bulge-to-total ratio, such that a host galaxy with Sersic n 4 typically derive at least 70% of their total host galaxy light from a bulge, but this number can be as low as 55%. Single-component Sersic fits to an AGN host galaxy are statistically very reliable to z < 1.25 (for ACS survey data like ours). In contrast, two-component fits involving separate bulge and disk components tend to overestimate the bulge fraction by ~10%, with uncertainty of order 50%.
The international effects of government spending composition

Abstract This paper incorporates a distinction between spending for government employment and spending for non-wage government consumption in a ‘new open economy macroeconomics’ model. Our results show that a permanent reduction in public employment in one country increases relative private consumption and appreciates the domestic exchange rate. We also compare announced reductions in domestic government employment and consumption, showing that these two policies have the same qualitative effects. When the reduction in public employment is used to finance increased government non-wage spending, the analytical results of the model are ambiguous, but a numerical analysis shows that relative consumption increases for a reasonable parameterization.
On the lower central series quotients of a graded associative algebra

We continue the study of the lower central series Li(A) and its successive quotients Bi(A) of a noncommutative associative algebra A, defined by L1(A)=A, Li+1(A)=[A,Li(A)], and Bi(A)=Li(A)/Li+1(A). We describe B2(A) for A a quotient of the free algebra on two or three generators by the two-sided ideal generated by a generic homogeneous element. We prove that it is isomorphic to a certain quotient of Kahler differentials on the non-smooth variety associated to the abelianization of A.
Allenyls and propargyls: versatile ligands in transition-metal chemistry

Abstract Mononuclear, binuclear, and trinuclear transition-metal allenyl and/or propargyl complexes are reviewed with respect to methods of synthesis, structure, and reaction chemistry. Structural relationships among the various types of complexes are presented and, to the extent possible, used to rationalize some patterns of reactivity. Recent developments in the field are accorded special emphasis.
The Recombination of Argon Ions and Electrons

Afterglow spectrum in argon due to recombination.---The arc spectrum of argon is found to persist approximately 0.001 sec. after an arc of 0.4 amp. in pure argon at 0.5 mm pressure is cut off. Lines involving jumps from high energy levels are relatively much stronger in the afterglow than in the arc. When sodium vapor is present the $D$ lines are strong in the arc but absent in the afterglow showing that the electron speeds in the afterglow are too low to excite the spectrum of argon by direct electron impact. The highly excited argon atoms must therefore be produced by the recombination of ions and electrons. The presence of 0.001 mm of hydrogen does not affect the intensity of the afterglow so that the persistence of metastable atoms is not involved in the production of the afterglow.Effect of applied potentials on the afterglow.---Accelerating voltages of 3 to 10 volts quench the afterglow during the period of application of 0.001 sec. Retarding after-voltages up to 90 volts have practically no effect. Measurements with an intermittently connected exploring electrode show that the velocities of the electrons are increased by the applied accelerating voltage but unaffected by the retarding voltage. The quenching is apparently the result of the decreased probability of recombination because of the higher velocities of the electrons. When low accelerating voltages have been applied for 0.001 sec. the intensity of the afterglow and the conductivity of the arc space in the period immediately following this application are both greater than they would be had the voltage not been applied. The intensity of the afterglow is thus directly related to the concentration of positive ions and the quenching of the afterglow shown to be connected with a saving up of ions as it should be if the effect of the after-voltages is to prevent recombination.Ordinary arc spectra are obtained under conditions which are here most unfavorable to the occurrence of recombination. They are presumaly primarily excitation spectra. The use of intermittent discharges for obtaining recombination spectra and strong high series members is suggested.The measurements show positive ion concentrations in the afterglow of the order of ${10}^{12}$ per cc. The mean energy of the electrons is 0.4 volt. From the measured rate of change of the concentration of ions, there results a value of 2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ for the coefficient of recombination. This value may be in error by a factor of 5 because of several unavoidable errors.
Capability Reconfiguration: An Analysis Of Incumbent Responses To Technological Change

I present a model of capability reconfiguration, integrating the Schumpeterian perspective on technological discontinuities with the dynamic capabilities literature to explain the responses of incumbents to technological change. I identify substitution, evolution, and transformation as three mechanisms of capability reconfiguration and then link the choice of reconfiguration mechanism to the nature of technological change and to the attributes of capabilities. I conclude that the extent to which the chosen mechanism enables incumbents to overcome cognitive and operational impediments influences their capacity to bridge capability gaps.
EVOLUTION OF THE UV EXCESS IN EARLY-TYPE GALAXIES

We examine the UV emission from luminous early-type galaxies as a function of redshift. We perform a stacking analysis using Galaxy Evolution Explorer images of galaxies in the NOAO Deep Wide Field Survey Bo?tes field and examine the evolution in the UV colors of the average galaxy. Our sample, selected to have minimal ongoing star formation based on the optical to mid-IR spectral energy distributions of the galaxies, includes 1843 galaxies spanning the redshift range 0.05 ? z ? 0.65. We find evidence that the strength of the UV excess decreases, on average, with redshift, and our measurements also show moderate disagreement with previous models of the UV excess. Our results show little evolution in the shape of the UV continuum with redshift, consistent either with the binary model for the formation of extreme horizontal branch (EHB) stars or with no evolution in EHB morphology with look-back time. However, the binary formation model predicts that the strength of the UV excess should also be relatively constant, in contradiction with our measured results. Finally, we see no significant influence of a galaxy's environment on the strength of its UV excess.
Corporate-sponsored foundations and earnings management

Abstract This study examines the strategic use of corporate philanthropy programs to achieve financial reporting objectives. Corporate-sponsored foundations allow managers to maintain stable levels of giving to charitable causes while providing substantial discretion as to the amount of contribution expense recorded on the income statement in any given period. I find that firms reporting small earnings increases make income-increasing discretionary foundation funding choices. This result is associated with firms that have strong equity market incentives to manage earnings. The evidence presented in this paper is consistent with firms using their charitable foundations as off-balance sheet reserves.
High-performance concurrency control mechanisms for main-memory databases

A database system optimized for in-memory storage can support much higher transaction rates than current systems. However, standard concurrency control methods used today do not scale to the high transaction rates achievable by such systems. In this paper we introduce two efficient concurrency control methods specifically designed for main-memory databases. Both use multiversioning to isolate read-only transactions from updates but differ in how atomicity is ensured: one is optimistic and one is pessimistic. To avoid expensive context switching, transactions never block during normal processing but they may have to wait before commit to ensure correct serialization ordering. We also implemented a main-memory optimized version of single-version locking. Experimental results show that while single-version locking works well when transactions are short and contention is low performance degrades under more demanding conditions. The multiversion schemes have higher overhead but are much less sensitive to hotspots and the presence of long-running transactions.
Quiet-Time Spectra and Abundances of Energetic Particles During the 1996 Solar Minimum

This report concerns the energy spectra and abundances of ions with atomic number, Z, in the interval 2 greater than or equal to Z and Z less than or equal to 36 and energies approximately 3-20 MeV/amu for solar and interplanetary quiet periods between November 1994 and April 1998 as measured by the large-geometry LEMT telescope on the Wind spacecraft near Earth. The energy spectra show the presence of galactic (GCR) and 'anomalous' cosmic ray (ACR) components, depending on the element. ACR components are reported for Mg and Si for the first time at 1 AU and the previous observation of S and Ar is confirmed. However, only GCR components are clearly apparent for the elements Ca, Ti, Cr, Fe, as well as for C. New limits are placed on a possible ACR contribution for other elements, including Kr.
Smoothing proximal gradient method for general structured sparse learning

We study the problem of learning high dimensional regression models regularized by a structured-sparsity-inducing penalty that encodes prior structural information on either input or output sides. We consider two widely adopted types of such penalties as our motivating examples: 1) overlapping group lasso penalty, based on the l1/l2 mixed-norm penalty, and 2) graph-guided fusion penalty. For both types of penalties, due to their non-separability, developing an efficient optimization method has remained a challenging problem. In this paper, we propose a general optimization approach, called smoothing proximal gradient method, which can solve the structured sparse regression problems with a smooth convex loss and a wide spectrum of structured-sparsity-inducing penalties. Our approach is based on a general smoothing technique of Nesterov. It achieves a convergence rate faster than the standard first-order method, subgradient method, and is much more scalable than the most widely used interior-point method. Numerical results are reported to demonstrate the efficiency and scalability of the proposed method.
Seismic Design of Friction-Damped Precast Concrete Frame Structures

This paper presents the seismic design of unbonded posttensioned precast concrete frame structures that use friction dampers for supplemental energy dissipation. A procedure is described to determine the friction damper slip forces and posttensioning steel areas needed to satisfy prescribed design lateral strength and energy dissipation requirements for a trial frame with given geometry, beam and column member dimensions, and selected damper distribution. The proposed design procedure assumes that the lateral strength requirements for the frame have been obtained from a linear elastic analysis of the structure under equivalent lateral forces. Nonlinear reversed-cyclic analyses of friction-damped precast concrete beam-column subassemblies and multistory frame structures under lateral loads are conducted to critically evaluate the design procedure and to identify areas where improvement may be needed. The analytical results show that friction-damped precast frames can be designed to achieve significant energy dissipation levels while maintaining a large level of self-centering capability due to the posttensioning force.
The bifurcation behavior of an autothermal packed bed tubular reactor

Abstract A model describing the dynamic behavior of a laboratory scale, autothermal tubular CO oxidation reactor with countercurrent coolant flow is presented. After a discussion of the solution to this model, the steady state version of the same model is subjected to an application of static bifurcation theory. Numerical difficulties encountered and overcome in this study include steady state reactor profiles accessible only by the use of spline collocation, a reactor model whose large number of differential equations requires efficient computational procedures for mapping the steady state behavior, and isolated solution branches reachable only by an algorithm developed to create three-dimensional solution surfaces. The reactor behavior uncovered will be cataloged over the relevant range of reactant inlet conditions by the use of a numerical singularity technique. Among the unusual solution branches found is a reactor behavior that will be shown to be a characteristic of not only this particular model, but of nonadiabatic tubular reactors in general.
Regularity criterion for 3D Navier-Stokes equations in terms of the direction of the velocity

In this short note we give a link between the regularity of the solution u to the 3D Navier-Stokes equation and the behavior of the direction of the velocity u/|u|. It is shown that the control of div(u/|u|) in a suitable L t/p (L x/q ) norm is enough to ensure global regularity. The result is reminiscent of the criterion in terms of the direction of the vorticity, introduced first by Constantin and Fefferman. However, in this case the condition is not on the vorticity but on the velocity itself. The proof, based on very standard methods, relies on a straightforward relation between the divergence of the direction of the velocity and the growth of energy along streamlines.
A method for using a time interval counter to measure frequency stability

An interval timer is used in a single-mixer frequency-stability measurement system in place of an event timer. The dead-time problem is avoided with the aid of a reference pulse train and an algorithm for ambiguity resolution. The noise floor test and the unfolding algorithm are described. Advantages of the technique are high precision, convenient interfacing, and low cost. A disadvantage is the vulnerability of the technique to missing data. >
Improved upper bounds for the information rates of the secret sharing schemes induced by the Vámos matroid

An access structure specifying the qualified sets of a secret sharing scheme must have information rate less than or equal to one. The Vamos matroid induces two non-isomorphic access structures V"1 and V"6, which were shown by Marti-Farre and Padro to have information rates of at least 3/4. Beimel, Livne, and Padro showed that the information rates of V"1 and V"6 are bounded above by 10/11 and 9/10 respectively. Here we improve those upper bounds to 8/9 for V"1 and 17/19 for V"6. We also indicate a general method that allows one to read off an upper bound for the information rate of V"6 directly from the coefficients of any non-Shannon inequality with certain properties, properties that hold for all 4-variable non-Shannon inequalities known to the author.
Fractal dimensions in perceptual color space: a comparison study using Jackson Pollock's art.

The fractal dimensions of color-specific paint patterns in various Jackson Pollock paintings are calculated using a filtering process that models perceptual response to color differences (L*a*b* color space). The advantage of the L*a*b* space filtering method over traditional red-green-blue (RGB) spaces is that the former is a perceptually uniform (metric) space, leading to a more consistent definition of “perceptually different” colors. It is determined that the RGB filtering method underestimates the perceived fractal dimension of lighter-colored patterns but not of darker ones, if the same selection criteria is applied to each. Implications of the findings to Fechner’s “principle of the aesthetic middle” and Berlyne’s work on perception of complexity are discussed.
Self-consistent treatment of crystal-electric-field-levels in the Anderson lattice

Abstract We consider an Anderson lattice model with a spin 1 2 degenerated conduction electron band and localized ionic CEF-levels, classified according to the irreducible representation of the point group of the lattice. We present the self-consistency equations for local approximations (“d → ∞” approximation) for the periodic Anderson model. It leads to a matrix formulation of the effective local density of states and the lattice f-Green's function. We derive the quasi-particle life-time which enters the Boltzmann transport equations. The impact of a k-dependent hybridization is discussed. We prove that vertex corrections will vanish, as long as all states of an irreducible representation couple to the conduction electron band with a hybridization matrix element of the same parity.
Continuum Modeling of the Mechanical and Thermal Behavior of Discrete Large Structures

In the present paper we introduce a rather straightforward construction procedure in order to derive continuum equivalence of discrete truss-like repetitive structures. Once the actual structure is specified, the construction procedure can be outlined by the following three steps: (a) all sets of parallel members are identified, (b) unidirectional 'effective continuum' properties are derived for each of these sets and (c) orthogonal transformations are finally used to determine the contribution of each set to the 'overall effective continuum' properties of the structure. Here the properties includes mechanical (stiffnesses), thermal (coefficients of thermal expansions) and material densities. Once expanded descriptions of the steps (b) and (c) are done, the construction procedure will be applied to a wide variety of discrete structures and the results will be compared with those of other existing methods.
An N = 2 dual pair and a phase transition

Abstract We carefully analyze the N = 2 dual pair of string theories in four dimensions introduced by Ferrara, Harvey, Strominger and Vafa. The analysis shows that a second discrete degree of freedom must be switched on in addition to the known “Wilson line” to achieve a non-perturbatively consistent theory. We also identify the phase transition this model undergoes into another dual pair via a process analogous to a conifold transition. This provides the first known example of a phase transition which is understood from both the type II and the heterotic string picture.
Computational singular perturbation method for dynamic systems

Abstract A computational method for stiff differential equations based on singular perturbation theory has recently been developed to solve chemical reaction systems. In this paper, the application of the method to general dynamic systems is reviewed and illustrated with simple examples. The method has several advantages over conventional singular perturbation analysis for complex systems.
LOW-MASS STAR FORMATION IN THE GUM NEBULA: THE CG 30/31/38 COMPLEX

We present photometric and spectroscopic results for the low-mass pre–main-sequence (PMS) stars with spectral types K–M in the cometary globule (CG) 30/31/38 complex. We obtained multiobject high-resolution spectra for the targets selected as possible PMS stars from multiwavelength photometry. We identified 11 PMS stars brighter than V = 16.5 with ages 5 Myr at a distance of approximately 200 pc. The spatial distribution of the PMS stars, CG clouds, and ionizing sources (O stars and supernova remnants) suggests a possible triggered origin of the star formation in this region. We confirm the youth of the photometrically selected PMS stars using the lithium abundances. The radial velocities of the low-mass PMS stars are consistent with those of the cometary globules. Most of the PMS stars show weak Hα emission with Wλ(Hα) < 10 A. Only one out of the 11 PMS stars shows a moderate near-IR excess, which suggests a short survival time (t < 5 Myr) of circumstellar disks in this star-forming environment. In addition, we find five young late-type stars and one Ae star that have no obvious relation to the CG 30/31/38 complex. We also discuss a possible scenario of the star formation history in the CG 30/31/38 region.
Delegation logic: A logic-based approach to distributed authorization

We address the problem of authorization in large-scale, open, distributed systems. Authorization decisions are needed in electronic commerce, mobile-code execution, remote resource sharing, privacy protection, and many other applications. We adopt the trust-management approach, in which "authorization" is viewed as a "proof-of-compliance" problem: Does a set of credentials prove that a request complies with a policy?We develop a logic-based language, called Delegation Logic (DL), to represent policies, credentials, and requests in distributed authorization. In this paper, we describe D1LP, the monotonic version of DL. D1LP extends the logic-programming (LP) language Datalog with expressive delegation constructs that feature delegation depth and a wide variety of complex principals (including, but not limited to, k-out-of-n thresholds). Our approach to defining and implementing D1LP is based on tractably compiling D1LP programs into ordinary logic programs (OLPs). This compilation approach enables D1LP to be implemented modularly on top of existing technologies for OLP, for example, Prolog.As a trust-management language, D1LP provides a concept of proof-of-compliance that is founded on well-understood principles of logic programming and knowledge representation. D1LP also provides a logical framework for studying delegation.
Fibonacci numbers in the topological theory of benzenoid hydrocarbons and related graphs

Fibonacci numbers are studied with respect to the topological theory of benzenoid hydrocarbons. These numbers are identified as the number of Kekule structures of nonbranched all-benzenoid hydrocarbons, the number of matchings of paths, the number of independent sets of vertices of paths, the number of nonattacking rooks of certain rook boards, as well as the number of Clar structures of certain benzenoid hydrocarbons. Fibonacci numbers were also identified as the number of conjugated circuits of certain benzenoid hydrocarbons and thus they were also related to the structure-resonance model. Maximal independent sets of caterpillar trees are also shown to be Fibonacci numbers.
Robust torque and torque-per-inertia optimization of a switched reluctance motor using the Taguchi methods

This paper presents the use of Taguchi methods in optimizing a switched reluctance motor (SRM) for applications requiring fast actuation. In these applications, the SRM is designed to provide a high electromagnetic torque-to-inertia ratio required for high rates of mechanical acceleration. This is accomplished using two simultaneous robust optimizations of an SRM, namely: 1) an optimization of the motor torque and 2) an optimization of the torque per inertia (mechanical acceleration). The Taguchi two-step optimization method and the zero-point-proportional dynamic response were used successfully in the double optimization. Two orthogonal arrays were used to lead the design of experiments (DOE). Finite-element analysis was used to compute the performance of the motor designs generated by the Taguchi DOE.
Polygallide RE2MGa9Ge2 (RE = Ce, Sm; M = Ni, Co) phases grown in molten gallium.

The quaternary intermetallics Ce2CoGa9Ge2, Ce2NiGa9Ge2, and Sm2NiGa9Ge2 were prepared by reacting elemental metals in excess of gallium at 850 °C. The title compounds crystallize in the tetragonal ...
Acetonitrile synthesis from CO, H2, and NH3 over iron catalysts

Abstract The reaction of 1 : 2 : 1 CO : H 2 : NH 3 at 698-723 K over reduced or prenitrided iron powder is initially active for production of CH 3 CN, but deactivates quickly due to extensive carbon deposition. Much longer periods of stability are observed over a highly dispersed, prereduced Fe/SiO 2 or Fe on carbon catalysts, suggesting the importance of small particle size for resistance to coking. Prereduced Fe/SiO 2 catalysts containing only Fe 2+ are less active for the nitrile reaction initially than those containing larger particle Fe 0 or Fe 2 N phases, but increase in activity with time on stream. Mossbauer spectroscopy measurements indicate that the nitrided Fe/SiO 2 catalyst is converted in minutes to Fe carbide during reaction. Thus little or no bulk nitrogen remains during reaction. Fe 0 in supported or unsupported catalysts quickly converts to a carbide during reaction as well. Unlike the unsupported catalyst, which ceases to be active, the supported catalyst always maintains some finite activity. This activity is attributed to the iron particles that are below the size that produces excessive carbon deposition.
Within-category discrimination of musical chords: perceptual magnet or anchor?

Recent speech research has begun to evaluate the internal structure of categories. In one such study, Kuhl (1991) found that discrimination was poorer for vowel stimuli that were more representative of the category (prototype, or P, set) than it was for less representative stimuli (nonprototype, or NP, set). This finding was interpreted as indicating that a category prototype may function as a “perceptual magnet,” effectively decreasing perceptual distance, and thus discriminability, between stimuli. The present study examines the function of prototypes in a musical category—another natural, but nonspeech category. Paralleling the Kuhl study, representative (P) and less representative (NP) sets of major triad stimuli were constructed, based on equal temperament. Musically experienced subjects rated the stimuli in each set for goodness as a major triad, with the highest rated stimulus serving as a prototype standard for a subsequent discrimination task. Results from the discrimination task demonstrated better performance in the P context than in the NP context. The current nonspeech results indicate that a prototype functions as an anchor rather than a magnet. In addition to providing a natural, nonspeech standard for comparison with speech findings, the results provide some important insights into the nature of musical categories.
Enzymatic strategies and biocatalysts for amide bond formation: tricks of the trade outside of the ribosome

Amide bond-containing (ABC) biomolecules are some of the most intriguing and functionally significant natural products with unmatched utility in medicine, agriculture and biotechnology. The enzymatic formation of an amide bond is therefore a particularly interesting platform for engineering the synthesis of structurally diverse natural and unnatural ABC molecules for applications in drug discovery and molecular design. As such, efforts to unravel the mechanisms involved in carboxylate activation and substrate selection has led to the characterization of a number of structurally and functionally distinct protein families involved in amide bond synthesis. Unlike ribosomal synthesis and thio-templated synthesis using nonribosomal peptide synthetases, which couple the hydrolysis of phosphoanhydride bond(s) of ATP and proceed via an acyl-adenylate intermediate, here we discuss two mechanistically alternative strategies: ATP-dependent enzymes that generate acylphosphate intermediates and ATP-independent transacylation strategies. Several examples highlighting the function and synthetic utility of these amide bond-forming strategies are provided.
A decentralized algorithm for spectral analysis

In many large network settings, such as computer networks, social networks, or hyperlinked text documents, much information can be obtained from the network's spectral properties. However, traditional centralized approaches for computing eigenvectors struggle with at least two obstacles: the data may be difficult to obtain (both due to technical reasons and because of privacy concerns), and the sheer size of the networks makes the computation expensive. A decentralized, distributed algorithm addresses both of these obstacles: it utilizes the computational power of all nodes in the network and their ability to communicate, thus speeding up the computation with the network size. And as each node knows its incident edges, the data collection problem is avoided as well. Our main result is a simple decentralized algorithm for computing the top k eigenvectors of a symmetric weighted adjacency matrix, and a proof that it converges essentially in O(@t"m"i"xlog^2n) rounds of communication and computation, where @t"m"i"x is the mixing time of a random walk on the network. An additional contribution of our work is a decentralized way of actually detecting convergence, and diagnosing the current error. Our protocol scales well, in that the amount of computation performed at any node in any one round, and the sizes of messages sent, depend linearly on the degree of the node, polynomially on k, but not at all on the (typically much larger) number n of nodes. To achieve independence of n, the coordinates of the computed eigenvectors are held locally by the nodes to which they correspond, enabling many eigenanalyses without distributing complete global state.
The Angelman Syndrome Protein Ube3A Regulates Synapse Development by Ubiquitinating Arc

Angelman Syndrome is a debilitating neurological disorder caused by mutation of the E3 ubiquitin ligase Ube3A, a gene whose mutation has also recently been associated with autism spectrum disorders (ASDs). The function of Ube3A during nervous system development and how Ube3A mutations give rise to cognitive impairment in individuals with Angleman Syndrome and ASDs are not clear. We report here that experience-driven neuronal activity induces Ube3A transcription and that Ube3A then regulates excitatory synapse development by controlling the degradation of Arc, a synaptic protein that promotes the internalization of the AMPA subtype of glutamate receptors. We find that disruption of Ube3A function in neurons leads to an increase in Arc expression and a concomitant decrease in the number of AMPA receptors at excitatory synapses. We propose that this deregulation of AMPA receptor expression at synapses may contribute to the cognitive dysfunction that occurs in Angelman Syndrome and possibly other ASDs.
Microwave-Assisted Direct Biaryl Coupling: First Application to the Synthesis of Aporphines

We have investigated the use of microwaves in a direct biaryl coupling reaction for the synthesis of analogs of the aporphine alkaloid nantenine. Our study shows that the aporphine core may be rapidly accessed from benzyl-tetrahydroisoquinoline substrates with this method. This is the first report of a microwave-assisted direct biaryl coupling reaction in the synthesis of aporphine molecules.
Outcomes of Phase II Clinical Trials with Single-Agent Therapies in Advanced/Metastatic Non-Small Cell Lung Cancer Published between 2000 and 2009

Purpose: We analyzed the outcomes of single-agent phase II clinical trials in non–small cell lung cancer (NSCLC) to determine trial parameters that predicted clinical activity. Exoerimental Design: Data on response rate (RR), progression-free survival (PFS), and overall survival (OS) from all English language, single-agent phase II trials in advanced/metastatic NSCLC indexed by PubMed (January 2000 through December 2009) were abstracted. Results: A total of 143 single-agent phase II trials (7,701 patients) were identified. The median RR was 10%, PFS 2.8 months, and OS 7.6 months. RR and PFS correlated with OS ( r = 0.46, P r = 0.52, P r = 0.61, P P = 0.005), longer median PFS (6 vs. 2.8 months, P = 0.005), and OS (11.3 vs. 7.5 months, P = 0.05) as compared with those of unselected patients. In multivariate analysis, only studies enriched for patients with molecular targets or including drugs that eventually gained FDA/EMA approval were associated with a higher RR, and longer PFS/OS. Conclusions: In phase II trials in NSCLC, RR and PFS correlated with OS. Studies enriched for patients with putative molecular drug targets were associated with higher therapeutic benefit as compared with those of unselected populations. Clin Cancer Res; 18(22); 6356–63. ©2012 AACR .
Adaptation of the fuzzy k-nearest neighbor classifier for manufacturing automation

The use of supervised pattern recognition technologies for automation in the manufacturing environment requires the development of systems that are easy to train and use. In general, these systems attempt to emulate an inspection or measurement function typically performed by a manufacturing engineer or technician. This paper describes a self- optimizing classification system for automatic decision making in the manufacturing environment. This classification system identifies and labels unique distributions of product defects denoted as `signatures'. The technique relies on encapsulating human experience through a teaching method to emulate the human response to various manufacturing situations. This has been successfully accomplished through the adaptation and extension of a feature-based, fuzzy k- nearest neighbor (k-NN) defined classes so that a significant reduction in feature space and problem complexity can be achieved. This k-NN implementation makes extensive use of hold-one-out results and fuzzy ambiguity information to optimize its performance. A semiconductor manufacturing case study will be presented. The technique uses data collected from in-line optical inspection tools to interpret and rapidly identify characteristic signatures that are uniquely associated with the manufacturing process. The system then alerts engineers to probable yield-limiting conditions that require attention.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Inferring Disability Status from Corrupt Data

In light of widespread concerns about the reliability of self-reported disability, we investigate what can be learned about the prevalence of work disability under various assumptions on the reporting error process. Developing a nonparametric bounding framework, we provide tight inferences under our strongest assumptions but then find that identification deteriorates rapidly as the assumptions are relaxed. For example, we find that inferences are highly sensitive to how one models potential inconsistencies between subjective self-assessments of work limitation and more objective measures of functional limitation. These two indicators appear to measure markedly different aspects of health status. Copyright © 2008 John Wiley & Sons, Ltd.
On complete intersections with trivial canonical class

Abstract We prove birational boundedness results on complete intersections with trivial canonical class of base point free divisors in (some version of) Fano varieties. Our results imply in particular that Batyrev–Borisov toric construction produces only a bounded set of Hodge numbers in any given dimension, even as the codimension is allowed to grow.