cssi/SciSciGPT-SciSciNet huggingface dataset:
COMMON STOCHASTIC TRENDS: EVIDENCE FROM THE LONDON METAL EXCHANGE

Recent evidence from cointegration theory points towards the efficiency of the London Metal Exchange. We show that on theoretical grounds this evidence could be misleading. We also conduct multivariate and univariate unit roots tests on prices of three different metals, namely: copper, lead and zinc. The price data are seasonal and unadjusted quarterly data from the London Metal Exchange and they cover the period from 1972.1–1987.4. The evidence presented here supports the presence of common stochastic trends in metal price movements.
An upper bound on the size of locally recoverable codes

In a locally recoverable or repairable code, any symbol of a codeword can be recovered by reading only a small (constant) number of other symbols. The notion of local recoverability is important in the area of distributed storage where a most frequent error-event is a single storage node failure (erasure). A common objective is to repair the node by downloading data from as few other storage node as possible. In this paper, we bound the minimum distance of a code in terms of of its length, size and locality. Unlike previous bounds, our bound follows from a significantly simple analysis and depends on the size of the alphabet being used.
Global Active Noise Control of a One-Dimensional Acoustic Duct Using a Feedback Controller

The active noise control of a one-dimensional hard-walled duct with a partially dissipative boundary condition is addressed. Previous techniques have attacked this problem by developing adaptive filters designed to cancel acoustic noise at a single measurement location. The work presented here applies modern, state space, control theory to globally reduce noise levels in a one-dimensional acoustic enclosure rather than at a single location. This global control requires only the addition of a single response measurement microphone and control speaker to the open-loop system
A Facile Synthesis of an (E)-4-Methyl-4-Hexenoic Acid Substituted Pyridine Analogue of Mycophenolic Acid

Abstract An (E)-4-methyl-4-hexenoic acid substituted pyridine analogue, 2, of mycophenolic acid has been synthesized from 6-methyl-2-pyridine-carboxaldehyde in 6 steps via a Claisen rearrangment.
Stereochemical evaluation of bis(phosphine) copper catalysts for the asymmetric alkylation of 3-bromooxindoles with α-arylated malonate esters

An improved method for the asymmetric alkylation of 3-bromooxindoles with α-arylated malonate esters is described. The asymmetric alkylation demonstrated was achieved up to 70% ee utilizing a copper(II) bis(phosphine) complex.
Discrete random variables over domains

In this paper we initiate the study of discrete random variables over domains. Our work is inspired by that of Daniele Varacca, who devised indexed valuations as models of probabilistic computation within domain theory. Our approach relies on new results about commutative monoids defined on domains that also allow actions of the non-negative reals. Using our approach, we define two such families of real domain monoids, one of which allows us to recapture Varacca's construction of the Plotkin indexed valuations over a domain. Each of these families leads to the construction of a family of discrete random variables over domains, the second of which forms the object level of a continuous endofunctor on the categories RB (domains that are retracts of bifinite domains), and on FS (domains where the identity map is the directed supremum of deflations finitely separated from the identity). The significance of this last result lies in the fact that there is no known category of continuous domains that is closed under the probabilistic power domain, which forms the standard approach to modelling probabilistic choice over domains. The fact that RB and FS are Cartesian closed and also are closed under a power domain of discrete random variables means we can now model, e.g. the untyped lambda calculus extended with a probabilistic choice operator, implemented via random variables.
On the Capacity of a Class of MIMO Cognitive Radios

Cognitive radios have been studied recently as a means to utilize spectrum in a more efficient manner. This paper focuses on the fundamental limits of operation of a MIMO cognitive radio network with a single licensed user and a single cognitive user. The channel setting is equivalent to an interference channel with degraded message sets (with the cognitive user having access to the licensed user's message). An achievable region and an outer bound is derived for such a network setting. It is shown that under certain conditions, the achievable region is optimal for a portion of the capacity region that includes sum capacity.
Publishing solutions for contemporary scholars: The library as innovator and partner

Purpose – The purpose of this article is to review the trend in academic libraries toward including scholarly communication, and by extension, electronic publishing, as part of their core mission, using the Cornell University Library as an example.Design/methodology/approach – The paper describes several manifestations of publishing activity organized under the Library's Center for Innovative Publishing, including the arXiv (http://arxiv.org/), Project Euclid (http://projecteuclid.org), and DPubS (http://DPubS.org).Findings – Libraries bring many competencies to the scholarly communications process, including expertise in digital initiatives, close connections with authors and readers, and a commitment to preservation. To add publishing to their responsibilities, they need to develop expertise in content acquisition, editorial management, contract negotiation, marketing, and subscription management.Originality/value – Academic libraries are making formal and informal publishing a part of their core activi...
A study of the dosimetry of small field photon beams used in intensity modulated radiation therapy in inhomogeneous media: Monte Carlo simulations, and algorithm comparisons and corrections

There is an increasing interest in the use of inhomogeneity corrections for lung, air, and bone in radiotherapy treatment planning. Traditionally, corrections based on physical density have been used. Modern algorithms use the electron density derived from CT images. Small fields are used in both conformal radiotherapy and IMRT, however, their beam characteristics in inhomogeneous media have not been extensively studied. This work compares traditional and modern treatment planning algorithms to Monte Carlo simulations in and near low-density inhomogeneities. Field sizes ranging from 0.5cmto5cm in diameter are projected onto a phantom containing inhomogeneities and depth dose curves are compared. Comparisons of the Dose Perturbation Factors (DPF) are presented as functions of density and field size. Dose Correction Factors (DCF), which scale the algorithms to the Monte Carlo data, are compared for each algorithm. Physical scaling algorithms such as Batho and Equivalent Pathlength (EPL) predict an increase in dose for small fields passing through lung tissue, where Monte Carlo simulations show a sharp dose drop. The physical model-based collapsed cone convolution (CCC) algorithm correctly predicts the dose drop, but does not accurately predict the magnitude. Because the model-based algorithms do not correctly account for the change in backscatter, the dose drop predicted by CCC occurs farther downstream compared to that predicted by the Monte Carlo simulations. Beyond the tissue inhomogeneity all of the algorithms studied predict dose distributions in close agreement with Monte Carlo simulations. Dose–volume relationships are important in understanding the effects of radiation to the lung. The dose within the lung is affected by a complex function of beam energy, lung tissue density, and field size. Dose algorithms vary in their abilities to correctly predict the dose to the lung tissue. A thorough analysis of the effects of density, and field size on dose to the lung and how modern dose calculation algorithms compare to Monte Carlo data is presented in this research project. This work can be used as a basis to further refine an algorithm's accuracy in low-density media or to correct prior dosimetric results.
A quantum Rosetta stone for interferometry

Heisenberg-limited measurement protocols can be used to gain an increase in measurement precision over classical protocols. Such measurements can be implemented using, for example, optical Mach—Zehnder interferometers and Ramsey spectroscopes. We address the formal equivalence between the Mach—Zehnder interferometer, the Ramsey spectroscope and a generic quantum logic circuit. Based on this equivalence we introduce the 'quantum Rosetta stone', and we describe a projective-measurement scheme for generating the desired correlations between the interferometric input states in order to achieve Heisenberg-limited sensitivity. The Rosetta stone then tells us that the same method should work in atom spectroscopy.
Consumer demand for potatoes: at home and away from home

Total U.S. consumption of potatoes has increased steadily over the past several decades, but significant changes have occurred in the way in which potatoes are consumed. This study identifies how socio-demographic and economic factors affect potato consumption at home and away from home, using data from the spring quarter of the 1977–1978 USDA Nationwide Food Consumption Survey. Tobit estimates indicate that the impact of income and value of time as well as factors such as race, location of residence and household size and composition on consumption differed for potatoes consumed at home versus away from home and by specific potato product. These results suggest the importance of segmenting the market in analysing consumption behaviour and developing marketing programmes.
Synthesis, Structure, and Magneto-transport of LnNi1-xSb2 (Ln = Y, Gd−Er)

Single crystals of the ternary antimonides LnNi1-xSb2 (Ln = Y, Gd−Er; x ∼ 0.4) have been grown from antimony flux. X-ray diffraction experiments reveal that these compounds crystallize in the tetragonal space group P4/nmm (No. 129) with Z = 2. Lattice parameters are a ∼ 4.3 A and c ∼ 9.3 A. Adopting the HfCuSi2 structure type, these compounds are layered and consist of Ln-capped Sb square nets and NiSb4 tetrahedra arranged in an anti-PbO fashion. The LnNi1-xSb2 compounds show antiferromagnetic ordering and field-dependent magnetization data are also presented. Transport measurements indicate metallic behavior and, most interestingly, positive magnetoresistance for each compound, with large positive magnetoresistance [MR(%) = (ρH − ρ0)/ρ0 × 100] above 100% for the Y-, Dy-, and Ho-analogues at 3 K and 9 T.
Xenon clusters in intense VUV laser fields.

A simple model is developed that quantitatively describes intense interactions of a vacuum ultraviolet (VUV) laser pulse with a xenon cluster. We find good agreement with a recent experiment [H. Wabnitz et al., Nature (London) 420, 482 (2002)]. In particular, the large number of VUV photons absorbed per atom, at intensities significantly below ${10}^{16}\text{ }\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2}$, is now understood.
Texture Discrimination Based Upon an Assumed Stochastic Texture Model

A new approach to texture discrimination is described. This approach is based upon an assumed stochastic model for texture in imagery and is an approximation to the statistically optimum maximum likelihood classifier. The construction and properties of the stochastic texture model are described and a digital filtering implementation of the resulting maximum likelihood texture discriminant is provided. The efficacy of this approach is demonstrated through experimental results obtained with simulated texture data. A comparison is provided with more conventional texture discriminants under identical conditions. The implications to texture discrimination in realworld imagery are discussed.
A Convenient Reagent for Aldehyde to Alkyne Homologation.

A convenient reagent for the one-carbon homologation of an aldehyde to the corresponding alkyne is reported. This reagent allows this conversion to conveniently be carried out on a large scale under ambient conditions.
Serotonin receptors expressed in Xenopus oocytes by mRNA from brain mediate a closing of K+ membrane channels.

Abstract Membrane currents evoked by serotonin (5-HT) were studied in Xenopus oocytes injected with rat brain mRNA. Intracellular EGTA was used to abolish the Ca2+-dependent oscillatory Cl− current to 5-HT, revealing an underlying smooth inward current. This was associated with a decreased membrane conductance, was antagonized by Ba2+ and Zn2+ (but not TEA), and probably arises through a closing of K+ channels. Half-maximal responses were obtained with 30 nM 5-HT, while 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) was ineffective. Furthermore, methysergide, mianserin and lysergic acid antagonized the K+-closing response to 5-HT, consistent with it being mediated through 5-HT1C receptors. The largest K+-closing responses were induced by a size fraction of mRNA which also induced a large K+ conductance, suggesting that the response requires expression of both receptors and K+ channels. The K+-closing response induced in the oocyte resembles the M- and S-type currents described in, respectively, mammalian and invertebrate neurons.
Numerical solution to the hermitian Yang-Mills equation on the Fermat quintic

We develop an iterative method for finding solutions to the hermitian Yang-Mills equation on stable holomorphic vector bundles, following ideas recently developed by Donaldson. As illustrations, we construct numerically the hermitian Einstein metrics on the tangent bundle and a rank three vector bundle on 2. In addition, we find a hermitian Yang-Mills connection on a stable rank three vector bundle on the Fermat quintic.
The Nucleon Elastic Form Factors

The nucleon elastic form factors are of fundamental interest, provide a unique testing ground for QCD motivated models of nucleon structure and are of critical importance to our understanding of the electromagnetic properties of nuclei. Even after an experimental effort spanning nearly 50 years the nucleon form factors are still the subject of active investigation. Advances in polarized beams, polarized targets and recoil polarimetry have been exploited over the last decade to produce an important and precise set of data. I review the status of the experimental efforts to measure the nucleon elastic form factors.
Proposal for a IR waveguide SASE FEL at the PEGASUS injector

Abstract Free Electron Lasers up to the visible regime are dominated by diffraction effects, resulting in a radiation size much larger than the electron beam. Thus the effective field amplitude at the location of the electron beam, driving the FEL process, is reduced. By using a waveguide, the radiation field is confined within a smaller aperture and an enhancement of the FEL performance can be expected. The PEGASUS injector at UCLA will be capable to provide the brilliance needed for an IR SASE FEL. The experiment Power Enhanced Radiation Source Experiment Using Structures (PERSEUS) is proposed to study the physics of a waveguide SASE FEL in a quasi 1D environment, where diffraction effects are strongly reduced as it is the case only for future FELs operating in the VUV and X-ray regime. The expected FEL performance is given by this presentation.
Vector extensions to LRLTRAN

The CDC STAR-100 brings a new concept in computing to LLL. The STAR is a string(vector) - oriented machine that is most efficient when it performs the same operations on sequentially stored operands. This approach to computer design opens up new areas of problem-solving techniques. Some algorithms that are long and cumbersome on other machines can be easily and efficiently programmed on the STAR computer. The vector extensions described in this paper represent an attempt to expand LRLTRAN (a dialect of FORTRAN) into a useful computer language for the STAR. The additions will enable an LRLTRAN-language compiler to produce vector code and hence allow the programmer to access, via LRLTRAN, the powerful STAR hardware instructions.
N-Heterocyclic carbene-catalyzed oxidations

N-Heterocyclic carbenes catalyze the oxidation of allylic and benzylic alcohols as well as saturated aldehydes to esters with manganese(IV) oxide in excellent yields. A variety of esters can be synthesized, including protected carboxylates. The oxidation proceeds under mild conditions, with low loadings of a simple triazolium salt pre-catalyst in the presence of base. Substrates containing potentially epimerizable centers are oxidized while preserving stereochemical integrity. The acyl triazolium intermediate generated under catalytic conditions can be employed as a chiral acylating agent in the desymmetrization of meso-diols.
A GENERAL AND EFFICIENT SYNTHESIS OF 2-PHENYLBENZOTHIAZOLES FROM DIPHENYL DISULFIDES

Abstract Benzothiazoles containing a substituted-phenyl at the 2 position can be synthesized cleanly and efficiently from the corresponding bis(2-aminophenyl) disulfide. Bis(2-aminophenyl) disulfides represent a stable source of 2-aminobenzenethiols.
Kinetic terms in warped compactifications

We develop formalism for computing the kinetic terms of 4d fields in string compactifications, particularly with warping. With the help of the Hamiltonian approach, we identify a gauge dependent inner product on the compactification manifold which depends on the warp factor. It is shown that kinetic terms are associated to the minimum value of the inner product over each gauge orbit. We work out the kinetic term for the complex modulus of a deformed conifold with flux, i.e. the Klebanov-Strassler solution embedded in a compact Calabi-Yau manifold. Earlier results of a power-like divergence are confirmed qualitatively (the kinetic term does contain the main effect of warping) but not quantitatively (the correct results differ by an order one coefficient).
Error estimation in linking heterogeneous data sources

There are many instances in an institution when there is a need to gather data from different departments. Record linkage is the technique used to bring together these separately compiled records into a useful format. Unfortunately, even with perfect data, error may be introduced when records from different sources are linked. We assume then, that at least for large-scale day-to-day operations, no data collection or repository produced by linking records from different sources should be declared error free. Thus, for quality assurance purposes, it will be useful to have methods that may be applied in day-to-day operations for estimating error produced by linking records. In this paper we describe our attempts to estimate the false negative error rate in record linkage serving periodic quality reporting.
Synthesis of new benzopyrans related to podophyllotoxin

Mannich bases of types 1 or 8, which are readily synthesized by condensation of 3,4-methylenedioxyphenol with aromatic aldehydes and pyrrolidine or piperazine, react with cyclic and acyclic β-diketones to yield benzopyrans. These benzopyrans are structurally similar to podophyllotoxin and like this drug some of the benzopyrans show in vivo anti-leukemic action in mice.
Cord Force Measurements in Radial Tires

Miniature force transducers in the form of strain gage instrumented tension links are used to measure the loads developed in the rayon cords in both the stabilizer and body plies of automobile tires of radial construction. These transducers are placed in series with the cord and are embedded in the rubber matrix of the tire during building. Cord forces are obtained at various wheel loads and inflation pressures for straight ahead rolling and cornering of the tires in operation. It is shown that a relatively simple formula can be used to theoretically predict the cord tension developed in the sidewall region due to inflation pressure.
Numerical Solution of the Compressible Boundary-Layer Equations Using the Finite Element Method

We study the application of the finite element method (FEM) to the boundary-layer equations governing both incompressible (with heat transfer) and compressible fluids in two dimensions. Numerical solutions for this set of equations have traditionally been obtained using the finite difference method (FDM), where the derivatives are approximated by difference quotients resulting in an algebraic representation of the partial differential equations. In FEM, the flow region is subdivided into a number of small regions called finite elements, and the dependent variables are interpolated within each element by functions of compatible order
Nucleon-Deuteron Scattering from an Effective Field Theory

Abstract We use an effective field theory to compute low-energy nucleon-deuteron scattering. We obtain the quartet scattering length using low energy constants entirely determined from low-energy nucleon-nucleon scattering. We find a th =6.33 fm, to be compared to a exp =6.35±0.02 fm.
Optimization of a fixed solar thermal collector

Abstract Criteria are presented for optimizing solar thermal energy collection. These criteria are then used in setting the design of a fixed solar thermal energy collector. This design is obtained by proceeding carefully through a series of optimization steps. While seeking near optimum performance, features have been retained which should lead to low cost. Initial optimization steps lead to an all glass vacuum collector tube whose side and lower walls are internally silvered to provide optimal Winston concentration on an interior glass tube coated with a selective absorber. Heat transfer calculations, performed for an array module of these collector tubes, produce values for the radiation, heat conduction and pumping losses and indicate operating conditions which minimize these losses. Near this minimum, heat conduction and pumping losses are small and can usually be neglected. Liquids provide much better heat transfer than gases. For liquid heat transfer fluids, the minimum loss collector tube window width (setting the transverse scale) is ∼3 cm and tube length ∼4 m, depending somewhat upon array area and the weighting used for the various losses. A window width of∼5 cm and tube length∼2 m should provide lower cost fabrication, while still allowing operation near minimum loss. Skills now used in the glass and lighting industry are expected to lead to low cost production of these tubes.
A Facile Method for the Preparation of S-(Alkylsulfenyl)cysteines

Abstract A general method for the facile preparation of S-(alkylsulfenyl)cysteines is described. It employs S-(methoxycarbonylsulfenyl)cysteine hydrochloride [H-Cys(Scm)-OH.HCl] as an easily accessible parent thiolactivated cysteine derivative.
Dilaton gravity and no-hair theorem in two dimensions

We study a general class of two-dimensional theories of the dilaton-gravity type inspired by string theory and show that they admit charged multiple-horizon black holes. These solutions are proved to satisfy scalar no-hair theorems.
Applications of microwave-accelerated organic synthesis

Abstract A comparison of microwave vs conventional heating is presented for a variety of Diels-Alder reactions, ortho-Claisen rearrangements, ene reactions, alkyl bromide preparations, Finkelstein reactions, oxidations, esterifications, hydrolyses, Williamson ether syntheses and other common organic transformations. In general, microwave-promoted reactions proceed with significant decreases in reaction times and in comparable chemical yield.
AN EXPANDED LUTTINGER MODEL

This paper generalizes Luttinger's model by introducing curvature (d2e(k)/dk2≠0) into the kinetic energy. An exact solution for arbitrary interactions is still possible in principle, but it now requires disentangling the eigenvalue spectrum of an harmonic string of interacting boson fields at each value of q. The additional boson fields, extracted from the excitation spectrum of the Fermi sea, are self-selected according to the nature and strength of the dispersion.
Harmonic functions for a class of integro-differential operators

We consider the operator \({\cal L}\) defined on \(C^2({\Bbb R}^d)\) functions by $$ \begin{array}{lll} {\cal L} f(x)&=&\frac{1}{2}\sum\limits_{i,j=1}^d a_{ij}(x)\frac{\partial^2f(x)}{\partial x_i\partial x_j}+\sum\limits_{i=1}^d b_i(x)\frac{\partial f(x)}{\partial x_i}\\ &&+\int_{{\Bbb R}^d\backslash\{0\}}\left[f(x+h)-f(x)-1_{(|h|\leq1)}h\cdot {\nabla} f(x)\right]n(x,h)dh. \end{array} $$ Under the assumption that the local part of the operator is uniformly elliptic and with suitable conditions on n(x,h), we establish a Harnack inequality for functions that are nonnegative in \( {\Bbb R}^d \) and harmonic in a domain. We also show that the Harnack inequality can fail without suitable conditions on n(x,h). A regularity theorem for those nonnegative harmonic functions is also proved.
Intramolecular light-induced electron transfer in a rigid, fixed-distance anthracene-N,N-dimethylaniline system. Exciplex-like behavior

In connection with the authors interest in light-induced electron transfer in rigid molecules, 2-(N,N-dimethylamino)-5,14-ethanopentacene (1) was synthesized. The anthracene electron acceptor and (N,N-dimethylamino)phenyl electron donor in 1 are held rigidly in a spatial configuration such that they are prevented from undergoing large structural changes before or after excitation. The fluorescence spectroscopy of 1 was investigated in solvents of differing polarity in order to probe for electron transfer from the (N,N-dimethylamino)phenyl donor to the excited anthracene acceptor, and the results are given.
Are the Dirac particles of the Standard Model dynamically confined states in a higher dimensional flat space

Some time ago Rubakov and Shaposhnikov suggested that elementary particles might be excitations trapped on a soliton in a flat higher dimensional space. They gave, as an example, ϕ4 theory in five dimensions with a bosonic excitation on a domain wall ϕcl in the fifth dimension. They also trapped a chiral Dirac particle on the domain wall with the interaction Lagrangian g ϕψ. The field equation for the Dirac field was -i. We show that a Dirac equation in eight flat dimensions with -gϕ replaced by a harmonic-oscillator "potential" in the four higher dimensions (plus a large constant M0) generates bound states in approximate SU (4) × SU (2) representations. These representations have corresponding "orbital" times "spin" quantum numbers and bear some resemblance to the quarks and leptons of the Standard Model. Soliton theory suggests that the harmonic-oscillator potential should rise only a finite amount. This will then limit the number of generations in a natural way. It will also mean that particles with su...
Selectivity of inhibition of matrix metalloproteases MMP-3 and MMP-2 by succinyl hydroxamates and their carboxylic acid analogues is dependent on P3' group chirality.

Abstract Structure–activity relationships are described for a series of succinyl hydroxamic acids 1a–o and their carboxylic acid analogues 2a–o as inhibitors of matrix metalloproteases MMP-3 and MMP-2. For this series (P1′=(CH2)3Ph, P2′=t-Bu) selectivity for the inhibition of MMP-2 was found to be strongly dependent on P3′.
Increasing the size of a piece of popcorn

Abstract Popcorn is an extremely popular snack food in the world today. Thermodynamics can be used to analyze how popcorn is produced. By treating the popping mechanism of the corn as a thermodynamic expansion, a method of increasing the volume or size of a kernel of popcorn can be studied. By lowering the pressure surrounding the unpopped kernel, one can use a thermodynamic argument to show that the expanded volume of the kernel when it pops must increase. In this project, a variety of experiments are run to test the qualitative validity of this theory. The results show that there is a significant increase in the average kernel size when the pressure of the surroundings is reduced.
A macromodular graphics system for protein structure research

Abstract A specialized graphics systems has been developed for protein research; this system achieves real-time display and manipulation for line-segment models containing up to 4095 end points. The hardware consists of three components: (1) a collection of hardware subroutines assembled from digital computer building blocks called macromodules, (2) vector-matrix transformation and display equipment and (3) a small stored-program computer. This paper provides a general description of the system. This work has been supported by the Division of Research Resources of the National Institutes of Health under Grant RR-00396. The development of macromodules has been partially supported by the Advanced Research Projects Agency of the Department of Defense under Contract SD-302. One of the authors (GRM) is partially supported by an Established Investigatorship from the American Heart Association.
A topological resolution theorem

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Adjoint functors, projectivization, and differentiation algorithms for representations of partially ordered sets

Abstract Adjoint functors and projectivization in representation theory of partially ordered sets are used to generalize the algorithms of differentiation by a maximal and by a minimal point. Conceptual explanations are given for the combinatorial construction of the derived set and for the differentiation functor.
Act similarity in case-based decision theory

Case-Based Decision Theory (CBDT) postulates that decision making under uncertainty is based on analogies to past cases. In its original version, it suggests that each of the available acts is ranked according to its own performance in similar decision problems encountered in the past. The purpose of this paper is to extend CBDT to deal with cases in which the evaluation of an act may also depend on past performance of different, but similar acts. To this end we provide a behavioral axiomatic definition of the similarity function over problem-act pairs (and not over problem pairs alone, as in the original model). We propose a model in which preferences are context-dependent. For each conceivable history of outcomes (to be thought of as the “context” of decision) there is a preference order over acts. If these context-dependent preference relations satisfy our consistency-across-contexts axioms, there is an essentially unique similarity function that represents these preferences via the (generalized) CBDT functional.
Private/Public School Choice and Student Performance Revisited

This paper examines the differences in an index of standardized test performance of urban private/public school seniors by race, using a sample of 4172 students from the 1992 US National Education Longitudinal Survey. In addition to using 257 exogenous variables to control for individual traits, family background, etc., we treat both student performance and school choice as jointly endogenous in the context of a simultaneous equations model with a latent variable: school choice. We find that while White students perform marginally better in private relative to public schools, a performance gain for private school minority students was not realized. Given the additional finding that school characteristics/quality do not affect minority student performance, we conclude that 'school choice' is mostly taken advantage of by White urban residents.
Correlations in Hawking radiation and the infall problem

It is sometimes believed that small quantum gravity effects can encode information as ‘delicate correlations’ in Hawking radiation, thus saving unitarity while maintaining a semi classical horizon. A recently derived inequality showed that this belief is incorrect: one must have order unity corrections to low energy evolution at the horizon (i.e. fuzzballs) to remove entanglement between radiation and the hole. In this paper we take several models of ‘small corrections’ and compute the entanglement entropy numerically; in each case this entanglement is seen to monotonically grow, in agreement with the general inequality. We also construct a model of ‘burning paper’, where the entanglement is found to rise and then return to zero, in agreement with the general arguments of Page. We then note that the fuzzball structure of string microstates offers a version of ‘complementarity’. Low energy evolution is modified by order unity, resolving the information problem, while for high energy infalling modes (E ≫ kT) we may be able to replace correlators by their ensemble averaged values. Israel (and others) have suggested that this ensemble sum can be represented in the thermo-field-dynamics language as an entangled sum over two copies of the system, giving the two sides of the extended black hole diagram. Thus high energy correlators in a microstate may be approximated by correlators in a spacetime with horizons, with the ensemble sum over microstates acting like the ‘sewing’ prescription of conformal field theory.
Conformational analysis of benzenediols: pyrocatechol, resorcinol and hydroquinone

Abstract Molecular orbital calculations are carried out for pyrocatechol, resorcinol and hydroquinone. The structural parameters, stable conformations, potential barrier heights, dipole moments and charges for these molecules are discussed. Only one stable isomer for pyrocatechol, three for resorcinol and two for hydroquinone are established.
Response of hot-element wall shear stress gages in unsteady turbulent flows

Experimentally determined response characteristics of two types or hot-element wall shear stress gages are described for unsteady turbulent flows. One is the substrate-type thin-film gage and the other is a gage with a small cavity below a surface-level thin-film quartz-fiber element. Two substrate-type gages were tested: a quartz-substrate gage, and a glue-on gage with a thin flexible substrate. Steady-flow gage calibrations were used in reducing unsteady flow data. The cavity gage showed excellent response to a steplike flow, whereas the two substrate gages exhibited response times on the order of tens of seconds for the same flow. Steady-flow shear stress turbulence levels indicated by the cavity and substrate gages were 28 and 12%, respectively
Silver-mediated fluorination of aryl silanes

A regiospecific silver-mediated fluorination of aryl silanes is reported. The reaction is operationally simple, and employs Ag2O as readily available, inexpensive silver source, which can be recovered.
Autonomous Landing of Miniature Aerial Vehicles

This paper outlines an algorithm for automated landing of miniature aerial vehicles (MAVs). Utilizing estimates of height above ground from barometric pressure and optic flow measurements, repeated landings were performed with a 1.5 m wingspan MAV. With height above ground estimated from barometric pressure measurements alone, landing errors averaged 7.6 m. When optic flow and barometric pressure measurements were combined to estimate height above ground, the average landing error was only 4.3 m.
Color and charge breaking minima in the MSSM

The scalar potential of theories with broken supersymmetry can have a number of local minima characterized by different gauge groups. Symmetry properties of the physical vacuum constrain the parameters of the MSSM. We discuss these constraints, in particular those that result from the vacuum stability with respect to quantum tunneling.
Effects of impurity scattering on electron-phonon resonances in semiconductor superlattice high-field transport

A nonequilibrium Green's function method is applied to model high-field quantum transport and electron-phonon resonances in semiconductor superlattices. The field-dependent density of states for elastic (impurity) scattering is found nonperturbatively in an approach which can be applied to both high and low electric fields. $I\ensuremath{-}V$ curves, and specifically electron-phonon resonances, are calculated by treating the inelastic (LO phonon) scattering perturbatively. Calculations show how strong impurity scattering suppresses the electron-phonon resonance peaks in $I\ensuremath{-}V$ curves, and their detailed sensitivity to the size, strength and concentration of impurities.
Structural change among agricultural input industries

Changes among agricultural input industries have important implications for US agriculture. Reasons for these changes have included the globalization of the marketplace, technological advances, and a changing farm sector. © 1993 John Wiley & Sons, Inc.
Cellular automaton rules conserving the number of active sites

This paper shows how to determine all of the unidimensional two-state cellular automaton rules of a given number of inputs which conserve the number of active sites. These rules have to satisfy a necessary and sufficient condition. If the active sites are viewed as cells occupied by identical particles, these cellular automaton rules represent evolution operators of systems of identical interacting particles whose total number is conserved. Some of these rules, which allow motion in both directions, mimic ensembles of one-dimensional pseudorandom walkers. Numerical evidence indicates that the corresponding stochastic processes might be non-Gaussian.
Modulation of Proliferating Renal Epithelial Cell Affinity for Calcium Oxalate Monohydrate Crystals

Adhesion of urinary crystals to distal tubular cells could be a critical event that triggers a cascade of responses ending in kidney stone formation. Monolayer cultures of distal nephron- derived MDCKI cells were used as a model to study crystal-cell interactions. COM crystal adhesion reached a peak 2 d after plating and progressively fell thereafter. The decline in crystal binding was accelerated by prostaglandin E2 (PGE2) supplemen- tation and delayed by blockade of PG production. Crystals avidly adhered to cells that migrated in to repair a scrape wound made in the monolayer and after a transient hypoglycemic insult. Exposure of MDCKI cells to uric acid crystals and soluble uric acid was also associated with increased crystal adhesion. Treatment of physi- cally or hypoglycemically injured cells with trypsin or neuramin- idase reduced crystal binding to baseline levels, suggesting that increased exposure of cell surface glycoproteins mediated the effect, whereas PGE2 treatment blunted crystal binding to regen- erating cells. Furthermore, when cells were grown in the presence of synthetic D-mannosamine analogues that can modify the con- formation of cell surface sialoglycoconjugates, crystal binding to proliferating cells was decreased, whereas blockade of N-glyco- sylation with tunicamycin increased crystal adhesion to these cells. Therefore, COM crystal binding is enhanced to growing renal cells, synthesis of N-glycosylated cell surface proteins is essential to downregulate crystal binding to cells, and this re- sponse is modulated by physiologic signals such as PGE2. Sialic acid residues seem to mediate crystal adhesion to growing cells, either directly or via linkage to other crystal-binding molecules. Subtle renal injury and subsequent nephron repair could be a factor promoting crystal adhesion and favoring calculus formation.
Optimal routing for closed queueing networks

Abstract Optimal routing is an important subclass of resource allocation and load balancing problems that has applications in file allocation, distributed database systems, local area networks, etc. In this article, we present a generalization of the vertex allocation theorem of Tripathi and Woodside. The vertex allocation theorem applies to routing of single customer chains in closed product form networks. Basically, the theorem states that to maximize the sum of throughputs, each customer should consistently use the same server for each request type rather than probabilistically choose among alternatives for each request. We show that vertex allocation is valid for any network of quasi-reversible queues and that the objective function can be any Markov reward function on the state space of the queueing network model. In many optimization problems the customers are not all known a priori but rather enter the system dynamically. We address the problem of optimally choosing the routing for a new customer being added to an operational system. We model the system as a closed multichain queueing network and show that properties of networks of quasi-reversible queues can be used to obtain efficient optimal routing algorithms for this case.
Manager–salesperson congruence in customer orientation and job outcomes: The bright and dark sides of leadership in aligning values

To create customer-oriented organizations, managers are often asked to promote a values-based vision. Yet, many managers struggle with transferring their values to employees making strategic value changes difficult. Despite this challenge, research has yet to demonstrate how managers effectively align values within the sales force, or the impact alignment has on job outcomes. Therefore, we develop and empirically test a conceptual framework to examine the role of transformational leadership in aligning salesperson customer orientation (CO) values. We find that transformational leadership is a strong mechanism in creating perceived value congruence, yet may have a surprising dark side. Results suggest that transformational managers achieve congruence by raising or, contrary to conventional wisdom, lowering salesperson CO values to meet the perceived values of the manager. Response surface modelling results support the importance of perceived manager values. Customer-oriented salespeople have higher job sat...
Janossy Densities of Coupled Random Matrices

We explicitly calculate the Janossy densities for a special class of finite determinantal random point processes with several types of particles introduced by Prahofer and Spohn and, in the full generality, by Johansson in connection with the analysis of polynuclear growth models. The results of this paper generalize the theorem we proved earlier with Borodin about the Janossy densities in biorthogonal ensembles. In particular our results can be applied to ensembles of random matrices coupled in a chain which provide a very important example of determinantal ensembles we study.
Synthesis and Investigation of Plutonium Oxide Cluster Ions:PuxOy+(x(<)(=)18)

Abstract The plutonium–oxygen system is fundamentally and technologically important. The primary goal of the present study was to prepare and carry out initial chemical studies on gas-phase plutonium oxide cluster ions, which would contribute to the general understanding of PuOx chemistry. In this effort, several plutonium oxide, oxide-hydroxide and hydroxide cluster ions, PuxOy(OH)z+, were synthesized by pulsed laser ablation of hydrated plutonium oxalate in vacuum. Cerium was studied for comparison, and a chemically less diversified oxide cluster system was observed. The large variety of PuxOy(OH)z+ compositions found is attributed to the accessibility of multiple oxidation states for Pu, and the results demonstrate the feasibility of preparing clusters with diverse stoichiometries and variable plutonium oxidation states. These clusters may be studied by various gas-phase techniques to illuminate the behavior of plutonium as a function of key variables, such as oxidation state, structure/coordination and bonding. In addition, some gas-phase reaction studies were carried out and at least one significant cluster reaction product with dimethylether was identified. This result demonstrates the desirability of studying plutonium cluster chemistry in ion traps where longer residence times, and more ion–molecule collisions will result in greater reaction efficiencies. The largest primary oxide cluster identified here comprised six Pu atoms, but two distinctive ‘magic number’ clusters were also produced, which incorporated 16 and 18 Pu atoms, respectively. These ‘magic number’ clusters suggest that special stabilities obtain for these species and that it may be possible to prepare plutonium oxide ‘nanocrystals’ in the gas phase for examination by techniques complementary to those applicable to bulk materials. The plutonium cluster compositions and abundances observed in this work are discussed in the context of the oxidation states, structures, and bonding exhibited by plutonium.
Perception of entrepreneurial opportunity: a general framework

Purpose – Previous research has predominantly approached the concept of entrepreneurial opportunities from either one of two perspectives: opportunities exist as objective phenomena in the environment waiting to be discovered by alert entrepreneurs, or opportunities are subjectively perceived and even created by individual entrepreneurs. This paper aims to put forward a framework of opportunity perception which demonstrates that all entrepreneurial opportunities possess both objective and subjective qualities, thus helping reconcile both perspectives.Design/methodology/approach – A conceptual framework is developed, based on previous literature and insights from entrepreneurship, economics, psychology and related disciplines.Findings – Various perspectives presented in previous research can be combined into a coherent framework that summarizes the components of entrepreneurial opportunity perception. Testable propositions are provided for future research.Originality/value – The authors show that elements ...
Beyond the Boltzmann factor for corrections to scaling in ferromagnetic materials and critical fluids

The Boltzmann factor comes from the linear change in entropy of an infinite heat bath during a local fluctuation; small systems have significant nonlinear terms. We present theoretical arguments, experimental data, and Monte-Carlo simulations indicating that nonlinear terms may also occur when a particle interacts directly with a finite number of neighboring particles, forming a local region that fluctuates independent of the infinite bath. A possible mechanism comes from the net force necessary to change the state of a particle while conserving local momentum. These finite-sized local regions yield nonlinear fluctuation constraints, beyond the Boltzmann factor. One such fluctuation constraint applied to simulations of the Ising model lowers the energy, makes the entropy extensive, and greatly improves agreement with the corrections to scaling measured in ferromagnetic materials and critical fluids.
Synthesis of sapphyrins via a ‘3+1+1’ procedure

Abstract Sapphyrins may be obtained in ca. 30% yield via the condensation of 1 equivalent of a tripyrrane dialdehyde with 2 equivalents of a β-substituted pyrrole, followed by oxidation with DDQ.
Laser Velocimeter Measurements in a Centrifugal Pump With a Synchronously Orbiting Impeller

Velocity profiles were measured in the impeller of a centrifugal pump with a two-directional laser velocimeter. Blade-to-blade profiles were measured at four circumferential positions and four radiiwithin and one outside the four-bladed impeller. Data are presented herein at two circumferential and three radial locations. The pump was tested in two configurations; with the impeller running centered within the pump, and with the impeller orbiting with a synchronous motion (e/r 2 =0.016). Variation in velocity profiles among the individual passages in the orbiting impeller were found
Analytic Solutions to the Constraint Equation for a Force-free Magnetosphere around a Kerr Black Hole

The Blandford-Znajek constraint equation for a stationary, axisymmetric black hole force-free magnetosphere is cast in a 3+1 absolute space and time formulation, following the work of Komissarov. We derive an analytic solution for fields and currents to the constraint equation in the far-field limit that satisfies the Znajek condition at the event horizon. This solution generalizes the Blandford-Znajek monopole solution for a slowly rotating black hole to black holes with arbitrary angular momentum. Energy and angular momentum extraction through this solution occurs mostly along the equatorial plane. We also present a nonphysical, reverse-jet-like solution.