cssi/SciSciGPT-SciSciNet huggingface dataset:
False vacuum decay in Jordan-Brans-Dicke cosmologies

The bubble nucleation rate in a first-order phase transition taking place in a background Jordan-Brans-Dicke cosmology is examined. The leading order terms in the nucleation rate when the Jordan-Brans-Dicke field is large (i.e., late times) are computed by means of a Weyl rescaling of the fields in the theory. It is found that despite the fact that the Jordan-Brans-Dicke field (hence the effective gravitational constant) has a time dependence in the false vacuum at late times the nucleation rate is time independent.
Long-time existence and convergence of graphic mean curvature flow in arbitrary codimension

Let f:Σ1↦Σ2 be a map between compact Riemannian manifolds of constant curvature. This article considers the evolution of the graph of f in Σ1×Σ2 by the mean curvature flow. Under suitable conditions on the curvature of Σ1 and Σ2 and the differential of the initial map, we show that the flow exists smoothly for all time. At each instant t, the flow remains the graph of a map ft and ft converges to a constant map as t approaches infinity. This also provides a regularity estimate for Lipschitz initial data.
Chemical Solution Deposition of PLZT Films on Base Metal Foils

In an effort to develop cost effective, volumetrically efficient, high charge density and high energy density capacitors, Pb(Zr,Ti)O 3 and La-doped Pb(Zr,Ti)O 3 films were deposited by chemical solution deposition on nickel and alloy foils. PZT films deposited on bare foils exhibited lower permittivity and more electric field hysteresis compared to films deposited on platinized silicon substrates, due to the formation of low capacitance interfacial layers and/or diffusion of foil elements into the PZT. However, an ultimate dielectric breakdown strength of approximately 1.35 MV/cm was obtained for a film thickness of 1.8 μm, corresponding to a withstand voltage of 245 V. A reduced temperature dependence of capacitance was observed with decreasing film thickness. In order to improve the dielectric response, barrier layers of LaNiO 3 , Ru, or Ir were deposited on top of the metal foils used as substrates. The barrier improved relative permittivity and reduced hysteresis in relative permittivity as a function of dc bias.
Microstructural Investigation of the Weld HAZ in a Modified 800H Alloy

Detailed metallographic investigations of Gleeble simulated HAZ samples in modified 800H were performed. Precipitate dissolution, gain growth, HAZ liquation and the hardness degradation behavior in modified 800H were also addressed. Results of this study agree with previous HAZ hot cracking and softening behavior evaluations. Modified 800H is one of the newly developed high-temperature alloys for applications in coal-fired power generating systems (Swindeman, 1991). Modified 800H possesses a greater creep and higher temperature tensile strength as compared to standard alloy 800 and conventional austenitic stainless steels. To achieve excellent creep and high-temperature tensile strength a thermomechanical treatment is applied during alloy fabrication (5--10% cold work). Therefore, grain growth, recrystallization, and precipitate dissolution and redistribution will occur in the weld HAZ during fabrication. Thus, both mechanical and metallurgical degradation may occur in the HAZ. Additionally, metallurgical reactions adjacent to the fusion boundary, including a partially melted region and constitutional liquation, may occur and influence the hot cracking resistance.
Image modeling with parametric texture sources for design and analysis of image processing algorithms

A novel statistical image model is proposed to facilitate the design and analysis of image processing algorithms. A mean-removed image neighborhood is modeled as a scaled segment of a hypothetical texture source, characterized as a 2-D stationary zero-mean unit-variance random field, specified by its autocorrelation function. Assuming that statistically similar image neighborhoods are derived from the same texture source, a clustering algorithm is developed to optimize both the texture sources and the cluster of neighborhoods associated with each texture source. Additionally, a novel parameterization of the texture source autocorrelation function and the corresponding power spectral density is incorporated into the clustering algorithm. The parametric auto-correlation function is anisotropic, suitable for describing directional features such as edges and lines in images. Experimental results demonstrate the application of the proposed model for designing linear predictors and analyzing the performance of wavelet-based image coding methods.
Rotational Sweepback of Magnetic Field Lines in Geometrical Models of Pulsar Radio Emission

We study the rotational distortions of the vacuum dipole magnetic field in the context of geometrical models of the radio emission from pulsars. We find that at low altitudes the rotation deflects the local direction of the magnetic field by at most an angle of the order of r(sup 2 sub n), where r(sub n) = r/R(sub lc), r is the radial distance and R(sub lc) is the light cylinder radius. To the lowest (i.e. second) order in r(sub n) this distortion is symmetrical with respect to the plane containing the dipole axis and the rotation axis ((Omega, mu) plane). The lowest order distortion which is asymmetrical with respect to the (Omega, mu) plane is third order in r(sub n). These results confirm the common assumption that the rotational sweepback has negligible effect on the position angle (PA) curve. We show, however, that the influence of the sweep back on the outer boundary of the open field line region (open volume) is a much larger effect, of the order of r(sup 1/2 sub n). The open volume is shifted backwards with respect to the rotation direction by an angle delta(sub o nu) approx. 0.2 sin alpha r(sup 1/2 sub n) where alpha is the dipole inclination with respect to the rotation axis. The associated phase shift of the pulse profile Delta phi(sub o nu) approx. 0.2 r(sup 1/2 sub n) can easily exceed the shift due to combined effects of aberration and propagation time delays (approx. 2r(sub n)). This strongly affects the misalignment of the center of the PA curve and the center of the pulse profile, thereby modifying the delay radius relation. Contrary to intuition, the effect of sweepback dominates over other effects when emission occurs at low altitudes. For r(sub n) < or approx. 3 x 10(exp -3) the shift becomes negative, i.e. the center of the position angle curve precedes the profile center. With the sweepback effect included, the modified delay-radius relation predicts larger emission radii and is in much better agreement with the other methods of determining r(sub n).
Possible magnetic activity in the low-mass X-ray binary EXO 0748-676

We report evidence of magnetic activity associated with the secondary star in the EXO 0748-676 low-mass X-ray binary system. An analysis of a sequence of five consecutive X-ray eclipses observed during 2003 December with the RXTE satellite brings out a feature occurring during ingress we interpret as the X-ray photoelectric absorption shadow, as seen by an observer at Earth, of a plasma structure suspended above the surface of the secondary star. The light curve feature consists of an initial drop in count rate to near zero (the absorption shadow) with a very short rebound to a significant fraction of the pre-ingress count rate and then a final plunge to totality over a total timescale of ~25 s. The ingress feature persists for at least five consecutive orbital periods (a total of ~19 hr), and possibly up to 5 days in our data. Our data also show significant post-egress dipping during this eclipse sequence, unusual for this source, indicating possible secondary star mass ejection during this episode.
STABILITY CRITERION FOR CONVOLUTION-DOMINATED INFINITE MATRICES

Let be the space of all -summable sequences on . An infinite matrix is said to have -stability if it is bounded and has bounded inverse on . In this paper, a practical criterion is established for the -stability of convolution-dominated infinite matrices.
Synthesis of Tetrazolo-Fused Benzodiazepines and Benzodiazepinones by a Two-Step Protocol Using an Ugi-Azide Reaction for Initial Diversity Generation.

A two-step strategy for the synthesis of arrays of tricyclic tetrazolo-fused benzodiazepines and benzodiazepinones has been investigated. The protocol uses ortho-N-Boc phenylisocyanides and phenylglyoxaldehydes or ethyl glyoxylate in the four-component Ugi-azide reaction to afford MCR (MultiComponent Reactions) derived adducts equipped with the desired diversity inputs. A subsequent acidic treatment (TFA/DCE) allows a simultaneous deprotectionecyclization leading to the final products. 2012 Elsevier Ltd. All rights reserved.
Technologies and health care in the 21st century

The factors shaping the nature and scope of health care in the 21st century are examined. Included are the technically driven infusion of new and innovative research and clinical tools; the diversity and capability of modern imaging methods; the predominance of diagnostic capabilities over effective therapy in clinical medicine; the focus of basic research on engineering issues such as instrumentation, biomaterials, modeling, and physiological functions; the growing use of image-based therapy; and the quest for causation in chronic conditions. >
Current OPEs in superconformal theories

It’s well known that in conformal theories the two- and three-point functions of a subset of the local operators — the conformal primaries — suffice, via the operator product expansion (OPE), to determine all local correlation functions of operators. It’s less well known that, in superconformal theories, the OPE of superdescendants is generally undetermined from those of the superprimaries, and there is no universal notion of superconformal blocks. We recall these and related aspects of 4d (S)CFTs, and then we focus on the super operator product expansion (sOPE) of conserved currents in 4d \( \mathcal{N} = 1 \) SCFTs. The current-current OPE J(x)J(0) has applications to general gauge mediation. We show how the superconformal symmetry, when combined with current conservation, determines the OPE coefficients of superconformal descendants in terms of those of the superconformal primaries. We show that only integer-spin real superconformal-primary operators of vanishing R-charge, and their descendants, appear in the sOPE. We also discuss superconformal blocks for four-point functions of the conserved currents.
Prediction of remaining life of power transformers based on left truncated and right censored lifetime data

Prediction of the remaining life of high-voltage power transformers is an important issue for energy companies because of the need for planning maintenance and capital expenditures. Lifetime data for such transformers are complicated because transformer lifetimes can extend over many decades and transformer designs and manufacturing practices have evolved. We were asked to develop statistically-based predictions for the lifetimes of an energy company’s fleet of high-voltage transmission and distribution transformers. The company’s data records begin in 1980, providing information on installation and failure dates of transformers. Although the dataset contains many units that were installed before 1980, there is no information about units that were installed and failed before 1980. Thus, the data are left truncated and right censored. We use a parametric lifetime model to describe the lifetime distribution of individual transformers. We develop a statistical procedure, based on age-adjusted life distributions, for computing a prediction interval for remaining life for individual transformers now in service. We then extend these ideas to provide predictions and prediction intervals for the cumulative number of failures, over a range of time, for the overall fleet of transformers.
A local greedy algorithm and higher-order extensions for global numerical continuation of analytically varying subspaces

We present a family of numerical implementations of Kato's ODE propagating global bases of analytically varying invariant subspaces of which the first-order version is a surprisingly simple "greedy algorithm" that is both stable and easy to program and the second-order version a relaxation of a first-order scheme of Brin and Zumbrun. The method has application to numerical Evans function computations used to assess stability of traveling-wave solutions of time-evolutionary PDE.
Optimal vaccine allocation to control epidemic outbreaks in arbitrary networks

We consider the problem of controlling the propagation of an epidemic outbreak in an arbitrary contact network by distributing vaccination resources throughout the network. We analyze a networked version of the Susceptible-Infected-Susceptible (SIS) epidemic model when individuals in the network present different levels of susceptibility to the epidemic. In this context, controlling the spread of an epidemic outbreak can be written as a spectral condition involving the eigenvalues of a matrix that depends on the network structure and the parameters of the model. We study the problem of finding the optimal distribution of vaccines throughout the network to control the spread of an epidemic outbreak. We propose a convex framework to find cost-optimal distribution of vaccination resources when different levels of vaccination are allowed.We illustrate our approaches with numerical simulations in a real social network.
Multicore and GPU algorithms for Nussinov RNA folding

Background One segment of a RNA sequence might be paired with another segment of the same RNA sequence due to the force of hydrogen bonds. This two-dimensional structure is called the RNA sequence's secondary structure. Several algorithms have been proposed to predict an RNA sequence's secondary structure. These algorithms are referred to as RNA folding algorithms.
Algorithms for graded injective resolutions and local cohomology over semigroup rings

Let Q be an affine semigroup generating Z^d, and fix a finitely generated Z^d-graded module M over the semigroup algebra k[Q] for a field k. We provide an algorithm to compute a minimal Z^d-graded injective resolution of M up to any desired cohomological degree. As an application, we derive an algorithm computing the local cohomology modules H"I^i(M) supported on any monomial (that is, Z^d-graded) ideal I. Since these local cohomology modules are neither finitely generated nor finitely cogenerated, part of this task is defining a finite data structure to encode them.
Toward the synthesis of mycalamides A, B and onnamide A: a highly stereoselective synthesis of the trioxadecalin ring system

Abstract A highly diastereoselective synthesis of the trioxadecalin ring system ( 5 ) of mycalamides A, B and onnamide A is described.
Optimizing information credibility in social swarming applications

With the advent of smartphone technology, it has become possible to conceive of entirely new classes of applications. Social swarming, in which users armed with smartphones are directed by a central director to report on events in the physical world, has several real-world applications. In this paper, we focus on the following problem: how does the director optimize the selection of reporters to deliver credible corroborating information about an event? We first propose a model, based on common intuitions of believability, about the credibility of information. We then cast the problem as a discrete optimization problem, and introduce optimal centralized solutions and an approximate solution amenable to decentralized implementation whose performance is about 20% off on average from the optimal while being 3 orders of magnitude more computationally efficient. More interesting, a time-averaged version of the problem is amenable to a novel stochastic utility optimization formulation, and can be solved optimally, while in some cases yielding decentralized solutions.
Vapor condensation on liquid surface due to laminar jet-induced mixing

The effects of system parameters on the interface condensation rate in a laminar jet-induced mixing tank are numerically studied. The physical system consists of a partially filled cylindrical tank with a subcooled jet discharge from the center of the tank bottom toward the liquid-vapor interface which is at a saturation temperature corresponding to the constant tank pressure. Liquid is also withdrawn from the outer part of the tank bottom to maintain the constant liquid level. The steady-state conservation equations in nondimensiohal form are solved by a finite-difference method for various system parameters including liquid height to tank diameter ratio (////>), tank to jet diameter ratio (Did}, liquid outflow to jet area ratio (Aout/A7), and a heat leak parameter (Nh) which characterizes the uniform wall heat-flux. It is found that the average Condensation Stanton number (Stc) is decreasing with increasing H/D, Did, and Nh. For small Nh9 Stc is nearly independent of Aout/A,. For R€J ^ 600, Stc is essentially equal to (d/D)2 if (Did} > 20 and Nh « 1.
Global Magnetohydrodynamical Simulations of Accretion Tori

Global time-dependent simulations provide a means to investigate time-dependent dynamic evolution in accretion disks. This paper seeks to extend previous local simulations by beginning a systematic effort to develop fully global three-dimensional simulations. The nonlinear development of the magnetorotational instability is investigated using a time-explicit finite difference code written in cylindrical coordinates. The equations of ideal magnetohydrodynamics are solved with the assumption of an adiabatic equation of state. Both a Newtonian potential and a pseudo-Newtonian potential are used. Two simplifications are also explored: a cylindrical gravitational potential (the "cylindrical disk") and axisymmetry. The results from those simulations are compared with fully three-dimensional global simulations. The global simulations begin with equilibrium pressure-supported accretion tori. Two different initial field geometries are investigated: poloidal fields that are constant along initial equidensity surfaces and toroidal fields with a constant ratio of gas to magnetic pressure. In both cases the magnetorotational instability rapidly develops and the torus becomes turbulent. The resulting turbulence transports angular momentum, and the torus develops an angular momentum distribution that is near Keplerian. A comparison with axisymmetric simulations shows that in three dimensions the magnetorotational instability can act as a dynamo and regenerate poloidal field, thereby sustaining the turbulence. As previously observed in local simulations, the stress is dominated by the Maxwell component. The total stress in the interior of the disk is ≈0.1-0.2 times the thermal pressure. At late time the disks are characterized by relatively thick configurations, with rapid time dependence and tightly wrapped, low-m spiral structures.
Ratiometric detection of mercury ions in water: accelerated response kinetics of azo chromophores having ethynyl ligand tethers

The metal-induced intramolecular cyclization reaction of an azo dye was exploited for the colorimetric detection of mercury ions in water. The molecular probe 3 responds selectively to nM-level Hg(II) ions in neutral aqueous solutions.
Fund Manager Succession in Closed‐End Mutual Funds

Managing the succession process by the hiring and firing of key executives is one of the important functions of a board of directors. In this research we study successions of fund managers in the closed-end mutual fund industry. The agency issues inherent in closed-end mutual funds makes them a unique laboratory for such a study. Our results suggest that while the overall abnormal returns of these manager changes are statistically insignificant, that the returns are more positive for funds with large expense ratios and for funds trading at a discount. We also find the abnormal returns are negatively related to the percentage of inside director stock ownership. Corporate bond funds and international equity funds react more negatively to these announcements than other types of funds. The abnormal returns do not appear to be related to board composition, but board composition does vary across fund type, and may therefore indirectly influence the results.
A K-theoretic note on geometric quantization

We give a purely K-theoretic proof of a case of the “quantization commutes with reduction” result, conjectured by Guillemin and Sternberg and proved by Meinrenken and Vergne. We show that the quantization is simply a pushforward in K-theory, and use Lerman's symplectic cutting and the localization theorem in equivariant K-theory to prove that quantization commutes with reduction. The case where G=S 1 and the action is free on the zero level set of the moment map is addressed.
Development of sizing nomograms for stand-alone photovoltaic/storage systems☆

Abstract This paper describes the development of a simplified technique for sizing stand-alone photovoltaic/storage systems. The sizing criterion is the long-term loss-of-load probability which is the fraction of the total energy demand that the photovoltaic system will not be able satisfy over a 23-year period. The technique was derived using 23 years of hourly insolation data from 20 U.S. weather stations. These data were used to develop correlations between the variability in insolation and average monthly horizontal insolation. The correlations were then used to generate sizing nomograms that give the array size as a function of average horizontal insolation and the storage capacity as a function of the long-term loss-of-load probability. The technique is valid for systems with a fixed tilt array, product or energy storage, and any hourly or daily demand profile provided that thee average monthly demand does not vary by more than ±10% from month to month.
On the Galois group of generalized Laguerre polynomials

Using the theory of Newton Polygons, we formulate a simple criterion for the Galois group of a polynomial to be "large." For a fixed � ∈ Q − Z<0, Filaseta and Lam have shown that the nth degree Generalized Laguerre Polynomial L (�) n (x) = P n=0 n+� n j � (−x) j /j! is irreducible for all large enough n. We use our criterion to show that, under these condi- tions, the Galois group of L (�) n (x) is either the alternating or symmetric group on n letters, generalizing results of Schur for � = 0,1.
Non-unitary minimal models, Bailey's Lemma and N =1,2 Superconformal algebras

Using the Bailey flow construction, we derive character identities for the N=1 superconformal models SM(p′,2p+p′) and SM(p′,3p′−2p), and the N=2 superconformal model with central charge c=3 Open image in new window from the nonunitary minimal models M(p,p′). A new Ramond sector character formula for representations of N=2 superconformal algebras with central element c=3Open image in new window is given.
Introducing the Elasticity of Spatial Data

The data quality of a vector spatial data can be assessed using the data contained within one or more data warehouses. Spatial consistency includes topological consistency, or the conformance to topological rules (Hadzilacos & Tryfona, 1992, RodrA­guez, 2005). Detection of inconsistencies in vector spatial data is an important step for improvement of spatial data quality (Redman, 1992; Veregin, 1991). An approach for detecting topo-semantic inconsistencies in vector spatial data is presented. Inconsistencies between pairs of neighboring vector spatial objects are detected by comparing relations between spatial objects to rules (Klein, 2007). A property of spatial objects, called elasticity, has been defined to measure the contribution of each of the objects to inconsistent behavior. Grouping of multiple objects, which are inconsistent with one another, based on their elasticity is proposed. The ability to detect groups of neighboring objects that are inconsistent with one another can later serve as the basis of an effort to increase the quality of spatial data sets stored in data warehouses, as well as increase the quality of results of data-mining processes
Non-Pyrolytic Syntheses of Buckybowls: Corannulene, Cyclopentacorannulene, and a Semibuckminsterfullerene

Corannulene (1), cyclopentacorannulene (2), and a C30H12 semibuckminsterfullerene (3) have been prepared by non-pyrolytic methods employing bromomethyl/dibromomethyl and/or dibromomethyl/dibromomethyl coupling with low-valent titanium or vanadium. Reductive coupling of tetrakis(dibromomethyl)fluoranthene (8) with vanadium(III) chloride and lithium aluminum hydride affords corannulene in 70−75% yield. Similarly, hexakis(dibromomethyl)fluoranthene (13) leads to cyclopentacorannulene in 20−30% yield, and dodecabromo(octamethyl)indenofluoranthene (6) affords semibuckminsterfullerene (3) in 20% yield.
An Untriggered Search for Optical Bursts

We present an untriggered search for optical bursts with the Robotic Optical Transient Search Experiment (ROTSE-I) telephoto array. Observations were taken that monitor an effective 256 deg2 field continuously over 125 hr to mROTSE = 15.7. The uniquely large field, moderate limiting magnitude, and fast cadence of ~10 minutes permit transient searches in a new region of sensitivity. Our search reveals no candidate events. To quantify this result, we simulate potential optical bursts with peak magnitude mp at t = 10 s, which fade as f = , where αt < 0. Simple estimates based on observational evidence indicate that a search of this sensitivity begins to probe the possible region occupied by gamma-ray burst (GRB) orphan afterglows. Our observing protocol and image sensitivity result in a broad region of high detection efficiency for light curves to the bright and slowly varying side of a boundary running from [αt,mp] = [-2.0, 6.0] to [-0.3, 13.2]. Within this region, the integrated rate of brief optical bursts is less than 1.1 × 10-8 s-1 deg-2. At ~22 times the observed GRB rate from BATSE, this suggests a limit on θopt/θγ 5, where θopt and θγ are the optical and gamma-ray collimation angles, respectively. Several effects might explain the absence of optical bursts, and a search of the kind described here but more sensitive by about 4 mag should offer a more definitive probe.
Reauthorization of the Federal Higher Education Act and Accountability for Student Learning: The Dog that Didn't Bark

An important feature of President George W. Bush's education policy was the promotion of accountability by requiring the collection and dissemination of data on student learning outcomes. In the case of primary-secondary education, this resulted in the No Child Left Behind act. When the Department of Education sought to initiate a rulemaking on measuring student achievement in postsecondary institutions, this was rebuffed by Congress in 2007 and then further precluded in the 2008 reauthorization of the Higher Education Act. This difference in outcomes reflects differences in policy issues, institutional relationships between federal, state and private actors, and interest group communities. As a result, explanations for the expansion of federal authority under No Child Left Behind do not necessarily transfer to postsecondary education. Copyright 2009, Oxford University Press.
An experimental evaluation of the constant β relating the contact stiffness to the contact area in nanoindentation

Measurements of mechanical properties by nanoindentation with triangular pyramidal indenters like the Berkovich rely heavily upon the relationship between the contact stiffness, S, the contact area, A, and the reduced elastic modulus, Er . This relationship is often written in the form S=2βEr (A/π)1/2, where β is a constant that depends on the geometry of the indenter. Although the most common values for β used in experimental measurements are 1.000 and 1.034, various theoretical analyses have yielded values as small as 1.00 or as large as 1.20, depending on the assumptions made to model the deformation. Here, the most appropriate value of β is explored by performing careful experiments in fused quartz with thin gold coatings applied to the surface to reveal the actual contact area when observed in the scanning electron microscope. Experiments were performed not only with the Berkovich indenter, but with five other three-sided pyramidal indenters with centreline-to-face angles ranging from 35.3° (cube cor...
Defects and Charge Transport near the Hematite (0001) Surface: An Atomistic Study of Oxygen Vacancies

Atomistic calculations were performed on a slab model of the (0001) surface of hematite as well as the bulk structure. In particular, the energetics of oxygen vacancies near the surface was studied. Atomistic modeling was used to establish the defect energies in the bulk versus distance from the surface. Transition state calculations were performed to compute barriers for several pathways of migration of oxygen vacancies in the bulk and at varying depths relative to the surface. We find energy barriers of several transitions considerably lowered closer to the surface. Considerations of literature data for electrical conductivity and Seebeck coefficient on bulk versus thin-film hematite suggest high populations of point defects near surfaces, in agreement with our predictions.
Pyramid simulation of image processing applications

Abstract Detecting lines in images using pyramid architecture is the main subject of this paper. The approach is based on the parallel calculation of Hough transform. A pyramid architecture of size n is a fine-grain architecture with a mesh base of size √n ∗ √n processors each holding a single pixel of the image. The pyramid operates in an SIMD mode. Two algorithms for computing the Hough transform are explained. The first algorithm initially uses different angles, θj's, and its complexity is O(k + log2n) with O(m) storage requirement. The second algorithm computes the Hough transform in a pipeline fashion for each angle θj at a time. This method produces results in O(k∗ log 2 n) time with O(1) storage, where k is the number of θj angles, m is the number of ρi normal distances from the origin, and n is the number of pixels. A simulation program is also described.
The Impact of Pre- and Post-Lecture Quizzes on Performance in Intermediate Accounting II

ABSTRACT: The purpose of this paper is to report the results of an investigation of the impact of online quizzing on accounting majors' examination performance in the second intermediate accounting course. Specifically, course sections with no quizzes, post-lecture quizzes, and a combination of pre- and post-lecture quizzes are compared. The data are based on 666 students completing Intermediate Accounting II at a large public university in the United States. Results suggest that using both pre- and post-lecture quizzes can lead to improved student preparation, increased student participation during class discussions, more effective use of lecture time, and significant improvement in students' performance on subsequent examinations. Significant interactions between GPA and the presence of pre- and post-lecture quizzes indicate that the effectiveness of specific quiz formats is contingent upon student aptitude level. Students with low GPAs benefit more from the addition of post-lecture quizzes, while stude...
Transaction costs and asset prices : a dynamic equilibrium model

In this article we study the effects of transaction costs on asset prices. We assume an overlapping generations economy with a riskless, liquid bond, and many risky stocks carrying proportional transaction costs. We obtain stock prices and turnover in closed form. Surprisingly, a stock's price may increase in transaction costs, and a more frequently traded stock may be less adversely affected by an increase in transaction costs. Calculations based on the 'marginal' investor overestimate the effects of transaction costs. For realistic parameter values, transaction costs have very small effects on stock prices but large effects on turnover.
Particle adhesion to surfaces under vacuum

The release of glass beads and standard dust from aluminum and glass substrates under centrifugation (simulating atmospheric pressure, low vacuum, and high vacuum conditions) was measured, with application to the estimation of contaminant particle release during spacecraft launch. For particles in the 10-100 micron range, dust was found to adhere more strongly than glass beads in all the cases considered. For most of the cases, dust and glass beads adhered more strongly to glass than to aluminum at all pressures. The adhesion force for dust on glass at 10 torr was shown to be as small as the value for dust on aluminum.
Packing algorithms for arborescences (and spanning trees) in capacitated graphs

In a digraph with real-valued edge capacities, we pack the greatest number of arborescences in time O(n 3m log(n 2/m)); the packing uses at mostm distinct arborescences. Heren andm denote the number of vertices and edges in the given graph, respectively. Similar results hold for integral packing: we pack the greatest number of arborescences in time O(min{n, logN}n 2m log(n 2/)) using at mostm + n − 2 distinct arborescences; hereN denotes the largest (integral) capacity of an edge. These resuts improve the best previous bounds for capacitated digraphs. The algorithm extends to several related problems, including packing spanning trees in an undirected capacitated graph, and covering such graphs by forests. The algorithm provides a new proof of Edmonds' theorem for arborescence packing, for both integral and real capacities, based on a laminar family of sets derived from the packing. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.
The Role of Ego Network Structure in Facilitating Ego Network Innovations

A great deal of research on innovation implicitly relies upon the network in which a firm is embedded to explain its innovative capabilities. Interestingly, however, most research examines innovation at the firm level, rather than at the network level. Thus, there is a significant gap in the literature regarding the effects of network structure on innovation within a firm's network. In this research, we contribute to the literature of supply chain innovations by developing and testing theoretically derived hypotheses regarding the effect of network structure on innovation output and distribution, as measured by the aggregate count and variance in the distribution of patents of the ego network in which a firm exists. Utilizing a manufacturing joint venture network dataset, we identify effects of various ego network constructs such as betweenness, density, brokerage, and weakness on ego network innovation. We find support for the idea that innovation in a supply chain is highly dependent upon the network structure of the interfirm relationships. Thus, it is not just what you know or how well you individually innovate, but also how well the firm can leverage its supply network connections that engender superior innovation outcomes.
Dynamical Structure of Peptide Molecules

In view of the importance of the peptide linkage in structural biology, we have carried out intensive investigations on peptide molecules consisting of a peptide linkage with one or two substituents in the gas phase by Fourier transform microwave spectroscopy, paying special attention to the internal rotation of the substituents relative to the central linkage framework. We have found that, in sharp contrast with the stiff structure around the central C-N bond of the linkage, the internal rotations of the substituents are of low frequency and thus of large amplitude and are extremely susceptible to their local environment such as the presence of other substituents.
Gauge fields on non‐commutative spaces and renormalization

Constructing renormalizable models on non-commutative spaces constitutes a big challenge. Only few examples of renormalizable theories are known, such as the scalar Grosse-Wulkenhaar model. Gauge fields are even more difficult, since new renormalization techniques are required which are compatible with the inherently non-local setting on the one hand, and also allow to properly treat the gauge symmetry on the other hand. In this proceeding (which is based on my talk given at the “Workshop on Noncommutative Field Theory and Gravity” in Corfu/Greece, September 8–15, 2013), I focus on this last point and present new extensions to existing renormalization schemes (which are known to work for gauge field theories in commutative space) adapted to non-commutative Moyal space.
Velocity Effects of Increased Variability in Monetary Growth in Egypt: A Test of Friedman's Velocity Hypothesis

: This paper tests Friedman's hypothesis that increased variability in the growth of money supply causes velocity to decline, using Egyptian data from the period 1960–99. The monetary aggregates M1 and M2 are decomposed into anticipated and unanticipated components and the variability of money growth is computed as the standard deviation of five years of monetary growth rates. Cointegration tests show that there is a statistically significant long-run relationship between the variability in money growth and velocity, for both M1 and M2. However, while increased variability in the growth of M2 is found to be associated with lower velocity — supporting Friedman's velocity hypothesis — increased variability in the growth of M1 seems to have no influence on velocity, possibly because the definition of M1 has changed over time. The findings also suggest that anticipated movements in M2 volatility are not neutral, in the sense that they do affect velocity. An important implication is that the scope for discretionary monetary policy in Egypt is somewhat circumscribed in the short run. However, if the Central Bank of Egypt were to make its decisions more transparent and pre-announce its policies, then velocity would be more predictable and monetary policy more potent. Resume: Sur la base de donnees relatives a l’Egypte pour la periode 1960–1990, cet article teste l’hypothese de velocite de Friedman, selon laquelle la variabilite accrue de la croissance de la masse monetaire ralentit la velocite. Les agregats monetaires M1 et M2 sont repartis en composantes prevues et imprevues et la variabilite de la croissance monetaire est calculee en tant qu’ecart type des taux de croissance monetaire sur une periode de cinq ans. Les tests de co-integration revelent l’existence d’une relation importante a long terme, du point de vue statistique, entre la variabilite de la croissance monetaire et la velocite, tant pour les agregats M1 que pour les agregats M2. Cependant, meme si l’on constate que la variabilite accrue de la croissance de M2 est associee a une faible velocite— ce qui corrobore l’hypothese de velocite de Friedman — la variabilite accrue de la croissance de M1 semble n’avoir aucune influence sur la velocite, peut-etre parce que la definition de M1 a change au fil des ans. Il ressort egalement des resultats que les mouvements prevus de la volatilite de M2 ne sont pas sans effet, en ce sens qu’ils influent sur la velocite. Une des incidences importantes est que la portee de la politique monetaire discretionnaire de l’Egypte est quelque peu circonscrite a court terme. Toutefois, si la Banque centrale de l’Egypte prenait des decisions plus transparentes et annoncait a l’avance ses politiques, la velocite serait alors plus previsible et la politique monetaire plus efficace.
An identity of hitting times and its application to the valuation of guaranteed minimum withdrawal benefit

In this paper we explore an identity in distribution of hitting times of a finite variation process (integrated geometric Brownian motion) and a diffusion process (geometric Brownian motion with affine drift), both of which arise from various applications in financial mathematics. We develop semi-analytical solutions to fair charges of variable annuity guaranteed minimum withdrawal benefit from both a policyholder’s perspective and an insurer’s perspective. The pricing framework from the policyholder’s perspective was known previously in the literature only by numerical methods, whereas the insurer’s pricing method was used in the industry but only with Monte Carlo simulations. While comparing their similarities and differences, we prove under the assumption of no friction cost the two pricing approaches are equivalent. In the presence of friction cost, the semi-analytic solutions in this paper lead to a fast and accurate algorithm for determining rider charges and other management fees.
Convenient fluorination of nitro and nitrile compounds with Selectfluor

Abstract A variety of nitro and nitrile compounds were fluorinated in good yields by Selectfluor under mild conditions. For these transformations to be successful, it is crucial to select proper amounts of an appropriate base as a function of the properties of the substrate and also to use Selectfluor only as required.
A Suboptimum Maximum Likelihood Approach to Parametric Signal Analysis

L'estimation discrete minimise une version de la fonction de vraisemblance en utilisant des techniques lineaires uniquement, evitant ainsi la complexite de calcul de la methode du maximum de vraisemblance
Synthesis and characterization of single-crystalline alkali titanate nanowires

A simple, one-step method has been utilized to synthesize functional ternary alkali titanate nanowires of single crystallinity. Nanostructural characterization shows that the nanowires are Na2Ti6O13 with [010] growth direction and KTi8O16.5 with [001] growth direction.
Business Interest Groups in Nineteenth-Century Brazil

Introduction 1. The genesis of Brazilian business interest groups 2. Leadership and organisation 3. Influence, ideology, and public relations 4. The export economy: agricultural quality, markets, and profits 5. The export economy: banking, credit, and currency 6. The export economy: manpower 7. Taxation 8. Industrialisation 9. Communications: regionalism perpetuated 10. Port areas and harbors: efficiency and rivalry 11. Business interest groups and economic and urban integration 12. Business interest groups and the Republic 13. Conclusion Notes Bibliography.
Design considerations for cryptography

Enciphering data can protect the transmission of information against unauthorized observers. One way of doing this when data is transmitted in binary form is to add random numbers to the data. If the string of random numbers is never repeated, the scheme is unbreakable. p. 398.
Scalable libraries for solving systems of nonlinear equations and unconstrained minimization problems

Developing portable and scalable software for the solution of large-scale optimization problems presents many challenges that traditional libraries do not adequately meet. Using object-oriented design in conjunction with other innovative techniques, we address these issues within the SNES (Scalable Nonlinear Equation Solvers) and SUMS (Scalable Unconstrained Minimization Solvers) packages, which are part of the multilevel PETSc (Portable, Extensible Tools for Scientific computation) library. The paper focuses on our design philosophy and its benefits in providing a uniform and versatile framework for developing optimization software and solving large-scale nonlinear problems. We also consider a three-dimensional anisotropic Ginzburg-Landau model as a representative application that exploits the packages' flexible interface with user specified data structures and customized routines for function evaluation and preconditioning. >
Bank-moneylender linkage as an alternative to bank competition in rural credit markets

This paper proposes a new method in which banks and moneylenders can link in rural credit markets. Banks and moneylenders, two of the major lenders in rural credit markets, differ in their information on borrowers and costs of funds. Due to information constraints, banks must deny further loans to borrowers who cannot repay a certain amount. In the linkage, these borrowers obtain loans from moneylenders, repay the banks, and have continuing access. We then evaluate conditions under which the linkage would be preferred to bank competition and find that the linkage dominates for a wide range of parameters. In light of recent proposals to liberalize Indian banking, the analysis provides a cautionary note to the limits of introducing banking competition in rural credit markets and provides an alternative. Copyright 2005, Oxford University Press.
Generalized phase spectrum

The generalized discrete transform (GT) r and its modified version (MGT) r have been defined and their properties have been developed. The phase or position spectra and the shift-invariant power spectra for these transforms have been developed. For the (GT) r family, these transforms range from the Walsh-Hadamard transform (WHT) to the discrete Fourier transform (DFT) whereas for the (MGT) r group, the range is from the modified WHT (MWHT) to the DFT. The power and phase spectra for these transforms represent groups of frequencies unlike the individual frequency composition characteristic of the DFT. Recently, it was shown that the input data can be recovered from the power and phase spectra of the WHT. This concept is now extended to the generalized transforms and it is shown that the original signal can be reconstructed from the phase and power spectra of any of the members of the (GT) r family. Also an efficient algorithm for evaluating the generalized phase spectrum for various cyclic shifts of the data sequence is developed.
Eco-Labeling Strategies and Price-Premium: The Wine Industry Puzzle

Although there is increasing use of eco-labeling, conditions under which eco-labels can command price premiums are not fully understood. In this article, we demonstrate that the certification of environmental practices by a third party should be analyzed as a strategy distinct from—although related to—the disclosure of the eco-certification through a label posted on the product. By assessing eco-labeling and eco-certification strategies separately, researchers can identify benefits associated with the certification process, such as improved reputation in the industry or increased product quality, independently from those associated with the actual label. In the context of the wine industry, we show that eco-certification leads to a price premium while the use of the eco-label does not.
Regulatory Federalism and Environmental Protection in the United States

In this paper we address two aspects of regulatory federalism in U.S. environmental policy. First, we suggest that environmental quality in U.S. states responds positively to increases in income. Second, we provide evidence that environmental quality did not decline when President Reagan's policy of new federalism returned responsibility for many environmental regulations to the states. Thus, state environmental quality appears to reflect more than just the dictates of federal policy. Additionally, we find that a “race to the bottom” in environmental quality did not materialize in the 1980s.
Toroidal and Annular Dehn Fillings

Suppose $M$ is a hyperbolic 3-manifold which admits two Dehn fillings $M(r_1)$ and $M(r_2)$ such that $M(r_1)$ contains an essential torus and $M(r_2)$ contains an essential annulus. It is known that $\Delta = \Delta(r_1, r_2) \leq 5$. We will show that if $\Delta = 5$ then $M$ is the Whitehead sister link exterior, and if $\Delta = 4$ then $M$ is the exterior of either the Whitehead link or the 2-bridge link associated to the rational number $3/10$. There are infinitely many examples with $\Delta = 3$.
Choosing Your Future: Temporal Distance and the Balance between Self-Control and Indulgence

This article investigates how temporal distance influences consumers’ self-control. We demonstrate that self-control is dependent on the content of currently active information in decisions for the future. When indulgence information is currently active, decisions for the future tend to be oriented toward self-control. When self-control information is currently active, decisions for the future tend to be oriented toward indulgence. In four experiments investigating two self-control domains (healthy eating and saving money), we find evidence for an information activation/inhibition account of the influence of temporal distance on self-control decisions.