cssi/SciSciGPT-SciSciNet huggingface dataset:
Efficient estimation of structural reliability for problems with uncertain intervals

Abstract The uncertain parameters in engineering design may appear as random or intervals based on the information available from the past history or physical experiments. When the random variables are provided with probability distribution functions, suitable methods have to be used in computing the failure probability. Similarly, when there are only bounds or ranges on some of the uncertain variables, failure analysis methods are needed to consider the complete range of uncertain intervals. When dealing with the combination of both random distributions and interval variables, the computational cost involved in estimating the reliability of the structure increases exponentially. Every combination of interval values requires one probabilistic based analysis, which is by itself an expensive procedure. Therefore, to make the problem tractable, use of function approximations is presented in this paper, which reduces the number of actual FEA/computational fluid dynamics (CFD) simulations. The proposed method is demonstrated with structural examples.
Connecting discrete and continuous path-dependent options

This paper develops methods for relating the prices of discrete- and continuous-time versions of path-dependent options sensitive to extremal values of the underlying asset, including lookback, barrier, and hindsight options. The relationships take the form of correction terms that can be interpreted as shifting a barrier, a strike, or an extremal price. These correction terms enable us to use closed-form solutions for continuous option prices to approximate their discrete counterparts. We also develop discrete-time discrete-state lattice methods for de- termining accurate prices of discrete and continuous path-dependent options. In several cases, the lattice methods use correction terms based on the connection between discrete- and continuous-time prices which dramatically improve con- vergence to the accurate price.
Monitoring of complex systems of interacting dynamic systems

Increases in functionality, power and intelligence of modern engineered systems led to complex systems with a large number of interconnected dynamic subsystems. In such machines, faults in one subsystem can cascade and affect the behavior of numerous other subsystems. This complicates the traditional fault monitoring procedures because of the need to train models of the faults that the monitoring system needs to detect and recognize. Unavoidable design defects, quality variations and different usage patterns make it infeasible to foresee all possible faults, resulting in limited diagnostic coverage that can only deal with previously anticipated and modeled failures. This leads to missed detections and costly blind swapping of acceptable components because of one's inability to accurately isolate the source of previously unseen anomalies. To circumvent these difficulties, a new paradigm for diagnostic systems is proposed and discussed in this paper. Its feasibility is demonstrated through application examples in automotive engine diagnostics.
A partial data result for the magnetic Schrödinger inverse problem

This article shows that knowledge of the Dirichlet-Neumann map on certain subsets of the boundary for input functions supported roughly on the rest of the boundary can be used to determine a magnetic Schr\"{o}dinger operator. With some geometric conditions on the domain, either the subset on which the DN map is measured or the subset on which the input functions have support may be made arbitrarily small. This is an improvement on the partial data result in a paper by Dos Santos Ferreira, Kenig, Sj\"{o}strand, and Uhlmann. The method involves modifying the Carleman estimate in that paper by conjugation with operators built from pseudodifferential pieces.
Gold(I)-catalyzed tandem cyclization approach to tetracyclic indolines

Two highly stereoselective cationic gold(I)-catalyzed tandem cyclization reactions of alkynylindoles are described. These reactions demonstrated a novel and general strategy to rapidly construct highly functionalized polycyclic indolines. This approach was successfully employed for a formal synthesis of the akuammiline alkaloid minfiensine.
Half-plane capacity and conformal radius

In this note, we show that the half-plane capacity of a subset of the upper half-plane is comparable to a simple geometric quantity, namely the euclidean area of the hyperbolic neighborhood of radius one of this set. This is achieved by proving a similar estimate for the conformal radius of a subdomain of the unit disc, and by establishing a simple relation between these two quantities.
Wireless communications with mobile devices in a web-based teleoperations environment

Deploying robotic devices for Web-based teleoperation is currently the domain of academic researchers, commercial enterprises and a small group of dedicated hobbyists. Before more people can deploy their own devices, a number of difficult issues need to be addressed. In previous work, we presented a reusable framework for Web-based teleoperation of robotic devices and attempted to address some of these deployment issues. However, a number of problems still remain, including how to support communication with a mobile remote device. Any remotely operated device requires some form of communication channel to its operator. In many current systems, this communications channel is composed of a long-haul network connection as well as a short-range connection between the device and a base unit. For a mobile device, one traditional solution for this short-range connection has been tethered operation. Tethered operation imposes a number of undesirable limitations on mobile devices however, so many researchers have turned to wireless communication as an alternative. As both the monetary and power costs associated with wireless communications continue to decrease, it becomes more viable as a general solution to the problem of providing communication between a base unit and a mobile device. We present an overview of the current state of the art in commercially available wireless communications and its implications for Web-based teleoperations. We also discuss how the requirements and implementation of our existing reusable framework will be modi ed in response to the new requirements imposed by wireless communication.
The Puiseux Characteristic of a Goursat Germ

Germsof Goursat distributions can be classified according to a geometric coding called an RVT code. Jean (ESAIM Control Optim Calc Var. 1:241---266, 1996) and Mormul (Cent Eur J Math 2:859---883, 2004) have shown that this coding carries precisely the same data as the small growth vector. Montgomery and Zhitomirskii (Mem Amer Math Soc 203(956):x+137, 2010) have shown that such germs correspond to finite jets of Legendrian curve germs, and that the RVT coding corresponds to the classical invariant in the singularity theory of planar curves: the Puiseux characteristic. Here, we derive a simple formula, Theorem 2, for the Puiseux characteristic of the curve corresponding to a Goursat germ with given small growth vector. The simplicity of our theorem (compared with the more complex algorithms previously known) suggests a deeper connection between singularity theory and the theory of nonholonomic distributions.
Synthesis of 9-fluorenylidenes and 9,10-phenanthrenes through palladium-catalyzed aryne annulation by o-halostyrenes and o-halo allylic benzenes.

A number of functionally substituted 9-fluorenylidenes and 9,10-phenanthrenes have been synthesized from substituted o-halostyrenes and o-halo allylic benzenes respectively in good yields by the palladium-catalyzed annulation of arynes. The methodology tolerates a variety of functional groups, including cyano, ester, aldehyde, and ketone groups, occurs under relatively mild reaction conditions, and involves the generation of two new carbon−carbon bonds, thus providing these important carbocyclic ring systems in a single synthetic step.
A Survey of Intrinsic Absorption in Active Galaxies using the Far Ultraviolet Spectroscopic Explorer

We present a survey of 72 Seyfert galaxies and quasars observed by the Far Ultraviolet Spectroscopic Explorer. We have determined that 72 of 253 available active galactic nuclei (AGNs) targets are viable targets for detection of intrinsic absorption lines. We examined these spectra for signs of intrinsic absorption in the O VI doublet (λλ1031.9, 1037.6) and Lyβ (λ1025.7). The fraction of Seyfert 1 galaxies and low-redshift quasars at z 0.15 that show evidence of intrinsic UV absorption is ~50%, which is slightly lower than that found by Crenshaw et al. (1999), who found 60% based on a smaller sample of Seyfert 1 galaxies observed with the Hubble Space Telescope. With this new fraction we find a global covering factor of the absorbing gas with respect to the central nucleus of ~0.4. Our survey is to date the largest search for intrinsic UV absorption with high spectral resolution and is the first step toward a more comprehensive study of intrinsic absorption in low-redshift AGNs.
Non-Locality as an Essential Feature of Brane Worlds

Weak gravity in the brane world scenario with a scalar field in the bulk between two end-of-the-world branes is investigated by using the doubly gauge invariant formalism. We review the result. that Einstein gravity is restored in the low energy limit and that high-energy corrections to Elinstein gravity can be mimicked by higher derivative terms. After that, it is argued that non-locality is one of essential features of brane worlds.
Dissociable perceptual-learning mechanisms revealed by diffusion-model analysis

Performance on perceptual tasks improves with practice. Most theories address only accuracy data and tacitly assume that perceptual learning is a monolithic phenomenon. The present study pioneers the use of response time distributions in perceptual learning research. The 27 observers practiced a visual motion-direction discrimination task with filtered-noise textures for four sessions with feedback. Session 5 tested whether the learning effects transferred to the orthogonal direction. The diffusion model (Ratcliff, Psychological Review, 85, 59–108, 1978) achieved good fits to the individual response time distributions from each session and identified two distinct learning mechanisms with markedly different specificities. A stimulus-specific increase in the drift-rate parameter indicated improved sensory input to the decision process, and a stimulus-general decrease in nondecision time variability suggested improved timing of the decision process onset relative to stimulus onset (which was preceded by a beep). A traditional d’ analysis would miss the latter effect, but the diffusion-model analysis identified it in the response time data.
The fracture stress and its dependence on slow crack growth

An analysis is presented which enables the fracture strength, (under constant stress-rate conditions) to be predicted from fracture mechanics data obtained during slow crack growth — by identifying and evaluating several key parameters. The predicted strength characteristics are illustrated using fracture mechanics data obtained for a soda lime silicate glass. Finally, the predicted strengths are compared with strengths measured in flexure on abraded soda lime silicate glass specimens. A good correlation is obtained, indicating an equivalence between micro- and macro-crack propagation conditions for this material.
Application of Hidden Markov Models to Biological Data Mining: A Case Study

In this paper we present an example of biological data mining: the detection of splicing junction acceptors in eukaryotic genes. Identification or prediction of transcribed sequences from within genomic DNA has been a major rate-limiting step in the pursuit of genes. Programs currently available are far from being powerful enough to elucidate the gene structure completely. Here we develop a hidden Markov model (HMM) to represent the degeneracy features of splicing junction acceptor sites in eukaryotic genes. The HMM system is fully trained using an expectation maximization (EM) algorithm and the system performance is evaluated using the 10-way cross- validation method. Experimental results show that our HMM system can correctly classify more than 94% of the candidate sequences (including true and false acceptor sites) into right categories. About 90% of the true acceptor sites and 96% of the false acceptor sites in the test data are classified correctly. These results are very promising considering that only the local information in DNA is used. The proposed model will be a very important component of an effective and accurate gene structure detection system currently being developed in our lab.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Synthesis and catalytic properties of eggshell cobalt catalysts for the Fischer-Tropsch synthesis

CO diffusional restrictions decrease C5+ synthesis rates and selectivity within large (1–3 mm) catalyst pellets often required in Fischer-Tropsch (FT) synthesis reactors. Eggshell catalysts, where Co is located preferentially near outer pellet surfaces, reduce the severity of these transport restrictions and lead to higher synthesis rates and C5+ selectivity. Maximum C5+ selectivities occur on catalysts with intermediate shell thickness, within which transport restrictions limit the removal of reactive olefins but not the arrival of reactants at catalytic sites. A new synthetic technique leads to sharp distributions of active sites near outer pellet surfaces by controlling the rate of imbibition of cobalt nitrate melts. Also, slow reduction of the impregnated salt leads to moderate Co dispersions (0.05–0.10) even at high local Co loadings present within shell regions.
Numerical studies of instanton induced baryon decay

We describe an application of computational techniques to the study of instanton induced baryon decay in high energy electroweak interactions.
Inflation and welfare in a stochastic production economy

Abstract This paper analyzes the relationship between money and labor supply, and derives money's optimal rate of return when production functions experience stochastic shocks. Increases in money's return increase both the deterministic component and variance of labor supply. Moreover, money's optimal rate is found to differ from both the rate suggested by Friedman and the. rates suggested by others for stochastic but pure endowment economies. Optimal policy is either inflationary or deflationary depending on parameterization.
New Brand Positioning and Pricing in an Oligopolistic Market

The positioning and pricing of a new brand requires knowledge about the relationship of both demand and cost with potential attribute locations and prices. This paper addresses this problem and illustrates it in the context of the automobile market. Multi-attribute expected utility theory which allows for consumer uncertainty about the brands is used to model individuals' behavior. Attribute weights are estimated from market survey data on brands' attributes and preferences using LINMAP as an estimation procedure. Expected utility is then updated using the multinomial logit model and choice data to account for the observation that stated preferences do not perfectly reflect the eventual choice. It is hypothesized that when faced with an actual choice price may become more important to the consumer, while other attributes may become more or less important than is reflected in stated preferences. The resulting estimated choice probabilities are aggregated to form demand functions facing each brand which depend on all brands' prices and attribute space locations. Assuming there is a price equilibrium in the existing market and that firms have the same variable cost function, variable costs as a function of a brand's attribute levels are estimated. Given the demand and cost functions facing each firm including the potential new entrant, the profit maximizing positioning and pricing of a new brand is analyzed using a game theoretic approach. A solution is sought under the assumption that incumbents react to entry by changing their prices. Possible approaches to the translation of the perceptual attribute positioning of the new brand to physical and engineering attributes are reviewed. Improvements and future extensions of the study are discussed.
Aqueous Synthesis and Structural Comparison of Rare Earth Niobates and Tantalates: (La,K,◻)2Nb2O7−x(OH)2 and Ln2Ta2O7(OH)2(◻ = vacancy; Ln = La−Sm)

Rare-earth niobates and tantalates are functional materials that are exploited as photocatalysts, host lattices for phosphors, and ion conductors. These phases are extremely challenging to synthesize by methods other than solid-state processing, which limits expansion of this useful class of materials. Hydrothermal processing in particular is hampered by the incompatibility of base-soluble tantalate or niobate with acid-soluble rare-earth oxides. Furthermore, an added challenge with tantalates is they are especially inert and insoluble. We present here a general hydrothermal process that has produced a range of rare-earth niobate/tantalate materials; including new phases, (La,K,◻)2Nb2O7−x(OH)2 (1) and Ln2Ta2O7(OH)2 (2) (◻ = vacancy, Ln = La−Sm—excluding radioactive promethium). The structures of 1 and the La-analogue of 2 were determined from powder X-ray diffraction data collected at the APS 11-BM line and corroborated by compositional analyses, infrared spectroscopy, 139La and 1H MAS NMR, and thermograv...
On an extension of the H^{k} mean curvature flow

In this note, we generalize an extension theorem in [Le-Sesum] and [Xu-Ye-Zhao] of the mean curvature flow to the Hk mean curvature flow under some extra conditions. The main difficulty in proving the extension theorem is to find a suitable version of Michael-Simon inequality for the Hk mean curvature flow, and to do a suitable Moser iteration process. These two problems are overcome by imposing some extra conditions which may be weakened or removed in our forthcoming paper. On the other hand, we derive some estimates for the generalized mean curvature flow, which have their own interesting.
Large Eddy Numerical Simulations of Turbulent Flows

Large eddy simulations are a numerical technique in which large-scale turbulent structures are computed explicitly, and the small structures are modeled. Arguments for believing this method to be superior to more conventional approaches are given, the basis of the method is given, and some typical results displayed. The results show that the method does have enormous promise, but much further development is required. I. Rationale T URBULENCE originates in instabilities of laminar flow, the precise nature of which depend on the geometry of the flow. Generally, the instabilities produce wavelike structures which can absorb energy from the mean flow. As they grow, nonlinear effects cause energy transfers to other modes, and, eventually, the noisy pattern that is generally regarded as "turbulence" results. Fully developed turbulence always reflects its origins to some degree. Since the maintenance of turbulence requires continuous nourishment, turbulent structures must be capable of absorbing energy from the mean flow. Although the mean flow is changed by the presence of turbulence, the energy absorbing structures bear some resemblance to those from which the turbulence originated. Thus, in turbulent flows, the large structures are the ones which absorb energy from the mean flow. They tend to be highly anisotropic, vortical in nature, and quite variable from flow to flow, and they are responsible for most of the property transport in turbulent flows. Furthermore, since the production mechanism is largely the stretching of vortices, which is a process requiring three dimensions, we would argue that all true turbulent flows are three dimensional. Through nonlinear interactions, they transfer some of their energy to smaller-scale structures, and the major function of the small structures is to dissipate the energy provided by the larger ones. In contrast, it is well known that the parameters of the small scales are determined almost entirely by the amount of energy they are required to dissipate. For this reason, they are much more universal than the large structures, and they are therefore nearly the same in all flows and nearly isotropic. Over the past 10 to 20 years, a large body of experimental evidence for the picture just presented has been accumulating. The total picture is, in fact, much more complicated than that described in the foregoing, and it is likely to be some time before many of the missing elements are filled in. Almost all of the approaches to the prediction of turbulent flow are based on Reynolds' idea of averaging the NavierStokes equations over an ensemble of identical flows or some equivalent (time or span averaging) to obtain an equation for the mean velocity. The equations are not closed because of the nonlinear terms in the Navier-Stokes equations, so approximations are needed, i.e., models must be introduced. Since many of the difficulties that occur in this approach have analogs in what we will be doing in this paper, no direct discussion of them will be given here. Rather, the interested reader is referred to the recent review of these methods by Reynolds.1
Assessment of relative stabilities of positional isomers of polyhedral heteronuclear clusters via a simplified method of bond energy calculations based on tight-binding approach and adjacent matrix method: applications to binary icosahedral clusters.

A new and simple method for assessing the relative stabilities of various positional isomers of a given heteronuclear cluster is described. The method is based on a tight-binding approach in conjun...
Cohomology of tilting modules over quantum groups and t-structures on derived categories of coherent sheaves

The paper is concerned with cohomology of the small quantum group at a root of unity, and of its upper triangular subalgebra, with coefficients in a tilting module. It turns out to be related to irreducible objects in the heart of a certain t-structure on the derived category of equivariant coherent sheaves on the Springer resolution, and to equivariant coherent IC sheaves on the nil-cone. The support of the cohomology is described in terms of cells in affine Weyl groups. The basis in the Grothendieck group provided by the cohomology modules is shown to coincide with the Kazhdan-Lusztig basis, as predicted by J. Humphreys and V. Ostrik. The proof is based on the results of [ABG ], [AB] and [B], which allow us to reduce the question to purity of IC sheaves on affine flag varieties.
Gravimagnetism, Causality, and Aberration of Gravity in the Gravitational Light-Ray Deflection Experiments

Experimental verification of the existence of gravimagnetic fields generated by currents of matter is important for a complete understanding and formulation of gravitational physics. Although the rotational (intrinsic) gravimagnetic field has been extensively studied and is now being measured by the Gravity Probe B, the extrinsic gravimagnetic field generated by the translational current of matter is less well studied. The present paper uses the post-Newtonian parametrized Einstein and light geodesics equations to show that the extrinsic gravimagnetic field generated by the translational current of matter can be measured by observing the relativistic time delay and/or light deflection caused by the moving mass. We prove that the extrinsic gravimagnetic field is generated by the relativistic effect of the aberration of the gravity force caused by the Lorentz transformation of the metric tensor and the Levi–Civita connection. We show that the Lorentz transformation of the gravity field variables is equivalent to the technique of the retarded Lienard–Wiechert gravitational potentials predicting that a light particle is deflected by gravitational field of a moving body from its retarded position so that both general-relativistic phenomena—the aberration and the retardation of gravity—are tightly connected and observing the aberration of gravity proves that gravity has a causal nature. We explain in this framework the 2002 deflection experiment of a quasar by Jupiter where the aberration of gravity from its orbital motion was measured with accuracy 20%. We describe a theory of VLBI experiment to measure the gravitational deflection of radio waves from a quasar by the Sun, as viewed by a moving observer from the geocentric frame, to improve the measurement accuracy of the aberration of gravity to a few percent.
Another self-similar blast wave - Early time asymptote with shock-heated electrons and high thermal conductivity

Accurate approximations are presented for the self-similar structures of nonradiating blast waves with adiabatic ions, isothermal electrons, and equation ion and electron temperatures at the shock. The cases considered evolve in cavities with power law ambient densities (including the uniform density case) and have negligible external pressure. The results provide the early time asymptote for systems with shock heating of electrons and strong thermal conduction. In addition, they provide analytical results against which two fluid numerical hydrodynamic codes can be checked.
A chiral rhodium carboxamidate catalyst for enantioselective C-H amination.

Rh2(S-nap)4, a chiral dirhodium tetracarboxamidate complex, has been developed and shown to be an effective catalyst for the asymmetric, intramolecular C−H amination of sulfamate esters. Enantiomeric excesses range from 60−99% for a collection of disparately substituted 3-arylpropylsulfamates. In addition, Rh2(S-nap)4 is found to promote chemoselective allylic C−H oxidation of unsaturated sulfamates, a property not observed with other dirhodium complexes tested to date.
A gap property for the growth of closed 3-manifold groups

We provide a lower bound for the uniform exponential growth rate of closed nonflat nonpositively curved 3-manifold groups. A detailed study of the uniform exponential growth rate of closed 3-manifold groups is also presented.
One-pot synthesis of enantiomerically enriched 2,3-disubstituted cyclopentanones via copper-catalyzed 1,4-reduction and alkylation

[reaction: see text]. Enantiomerically enriched 2,3-disubstituted cyclopentanones were prepared via copper-catalyzed 1,4-reduction of 3-substituted cyclopentenones followed by alkylation of the resulting silyl enol ether. Using this procedure, trans-2,3-disubstituted cyclopentanones were produced in moderate to good overall yields (42-67%) and with excellent enantiomeric and diastereomeric excesses. The reduction and alkylation were performed in a single reaction vessel.
Finite Larmor Radius Effects on the Magnetorotational Instability

The linear dispersion relation for the magnetorotational instability (MRI) is derived including finite Larmor radius (FLR) effects. In particular, the Braginskii form of the ion gyroviscosity, which represents the first-order FLR corrections to the two-fluid equations, is retained. It is shown that FLR effects are the most important effects in the limit of weak magnetic fields and are much more important than the Hall effect when βi 1, where βi is the ratio of the ion thermal pressure to the magnetic pressure. FLR effects may completely stabilize even MRI modes having wavelengths much greater than the ion Larmor radius. Some implications for astrophysical accretion disks are discussed.
Volatile-rich Earth-Mass Planets in the Habitable Zone

A small planet is not necessarily a terrestrial planet. Planets that form beyond the snow line with too little mass to seed rapid gas accretion (10 M⊕) should be rich in volatile ices like H2O and NH3. Some of these planets should migrate inward by interacting with a circumstellar disk or with other planets. Such objects can retain their volatiles for billions of years or longer at ~1 AU as their thick steam atmospheres undergo slow hydrodynamic escape. These objects could appear in future surveys for extrasolar Earth analogs.
The Theoretical Benefits of Food Safety Policies: A Total Economic Value Framework

In this paper we examine consumer benefits from food safety policy. The main objective is to develop a model that integrates important insights from the literature on consumers' responses to food safety. We consider four consumer responses: product avoidance, brand switching, averting behavior, and mitigation. We suggest how these responses are affected by consumers' knowledge of marginal product contamination, the effect of averting on marginal product contamination, the health effects of total exposure to contaminants, and the mitigation expense associated with these health effects.
Japanese and Korean automobile exports and the Alchian-Allen theorem

This paper compares data on Japanese and Korean automobile exports to the USA to examine consistency with the Alchian–Allen theorem. The theorem suggests that imposing a per unit charge such as transport cost will lower the relative price and increase the relative consumption of higher quality cars. Empirical results show that the relative price of higher quality cars is not necessarily lower with increased shipping costs, measured by CIF charges (cost, insurance and freight). A possible explanation is that insurance and other shipping charges are imposed based on the car price, and these charges reduce or eliminate the Alchian–Allen effect of per–unit freight charge.
On the modeling of electromagnetically coupled microstrip antennas--The printed strip dipole

A generalized solution for a class of printed circuit antennas excited by a strip transmission line is presented. The strip transmission line may be embedded inside or printed on the substrate. As an example, microstrip dipoles electromagnetically coupled (Parasitically excited) to embedded strip transmission line have been analyzed accurately, and design graphs are provided for a specific substrate material. These graphs permit the establishment of a design procedure which yields the microstrip dipole length, overlap, offset, and substrate thickness with the goal of a desired input match for a given substrate material. The method accounts for conductor thickness and for arbitrary substrate parameter. Comparison with experiment shows excellent agreement.
Effect of Geometry on the Unsteady Type-IV Shock Interaction

This work describes the effect of cowl geometry on the unsteady behavior of a type-IV shock interaction. The numerical procedure used for the thin-layer approximation to the compressible Navier› Stokes calculations is a second-order central difference approximation for the diffusion terms and a total variation diminishing type scheme for the inviscid terms. The calculations show that the peak surface pressure, the impingement location of the supersonic jet, and the time required for the development of the interaction are functions of both the impinging shock location and the cowl geometry. In addition, it is shown that the peak pressure loads associated with the type-IV shock interaction can be reduced by changing the geometric shape of the cowl.
Multigrid algorithms for optimization and inverse problems

A variety of new imaging modalities, such as optical diffusion tomography, require the inversion of a forward problem that is modeled by the solution to a three-dimensional partial differential equation. For these applications, image reconstruction can be formulated as the solution to a non-quadratic optimization problem. In this paper, we discuss the use of nonlinear multigrid methods as both tools for optimization and algorithms for the solution of difficult inverse problems. In particular, we review some existing methods for directly formulating optimization algorithm in a multigrid framework, and we introduce a new method for the solution of general inverse problems which we call multigrid inversion. These methods work by dynamically adjusting the cost functionals at different scales so that they are consistent with, and ultimately reduce, the finest scale cost functional. In this way, the multigrid optimization methods can efficiently compute the solution to a desired fine scale optimization problem. Importantly, the multigrid inversion algorithm can greatly reduce computation because both the forward and the inverse problems are more coarsely discretized at lower resolutions. An application of our method to optical diffusion tomography shows the potential for very large computational savings.
Why Income Comparison is Rational

A major factor affecting a person s happiness is the gap between their income and their neighbors , independent of their own income. This effect is strongest when the neighbor has moderately higher income. In addition a person s lifetime happiness often follows a "U" shape. Previous models have explained subsets of these phenomena, typically assuming the person has limited ability to assess their own (hedonic) utility. Here I present a model that explains all the phenomena, without such assumptions. In this model greater income of your neighbor is statistical data that, if carefully analyzed, would recommend that you explore for a new income-generating strategy. This explains unhappiness that your neighbor has greater income, as an emotional "prod" that induces you to explore, in accord with careful statistical analysis. It explains the "U" shape of happiness similarly. Another benefit of this model is that it makes many falsifiable predictions.
A Hexanuclear Cobalt(II) Cluster Incorporated in a Banana-Shaped Tungstovanadate: [(Co(OH2)Co2VW9O34)2(VW6O26)]17–

The hexanuclear cobalt-containing tungstovanadate complex, Na17[(Co(OH2)Co2VW9O34)2(VW6O26)]·31H2O (1) has been synthesized through reaction of cobalt nitrate, sodium tungstate, and V2O5 in acetate buffer solution. The title compound has been characterized by X-ray crystallography, elemental analysis, FTIR, UV/Vis, and 51V NMR spectroscopy and by cyclic voltammetry. Complex 1 crystallizes in the monoclinic space group P21/c (a = 15.706(3) A, b = 21.973(5) A, c = 35.080(8) A, α = 90°, β = 97.420(3)°, γ = 90°; V = 12005(5) A3; Z = 4; based on 192337 independent reflections), which consists of two tri-CoII substituted B-α-[(Co(OH2)Co2VW9O39)] Keggin units bridged by one unique [VW6O16] fragment leading to a banana-shaped structure with idealized C2ν symmetry. Stability studies show that polyoxoanion 1 ultimately transforms into the tetracobalt-containing sandwich-type polyoxoanion, 2, as confirmed by 51V NMR and X-ray crystallographic analyses. Polyoxoanion 1 shows catalytic activity for the H2O2-based epoxidation of 1-hexene and cyclohexene in 1,2-dichloroethane solvent.
Equivalence of SQL queries in presence of embedded dependencies

We consider the problem of finding equivalent minimal-size reformulations of SQL queries in presence of embedded dependencies [1]. Our focus is on select-project-join (SPJ) queries with equality comparisons, also known as safe conjunctive (CQ) queries, possibly with grouping and aggregation. For SPJ queries, the semantics of the SQL standard treats query answers as multisets (bags), whereas the stored relations are treated either as sets, which is called bag-set semantics, or as bags, which is called bag semantics. (Under set semantics, both query answers and stored relations are treated as sets.)In the context of the above Query-Reformulation Problem, we develop a comprehensive framework for equivalence of CQ queries under bag and bag-set semantics in presence of embedded dependencies, and make a number of conceptual and technical contributions. Specifically, we develop equivalence tests for CQ queries in presence of arbitrary sets of embedded dependencies under bag and bag-set semantics, under the condition that chase [10] under set semantics (set-chase) on the inputs terminates. We also present equivalence tests for CQ queries with grouping and aggregation in presence of embedded dependencies. We use our equivalence tests to develop sound and complete (whenever set-chase on the inputs terminates) algorithms for solving instances of the Query-Reformulation Problem with CQ queries under each of bag and bag-set semantics, as well as for instances of the problem with aggregate queries.Our contributions are clearly applicable beyond the Query-Reformulation Problem considered in this paper. Specifically, the results of this paper can be used in developing algorithms for rewriting CQ queries and queries in more expressive languages (e.g., including grouping and aggregation, or arithmetic comparisons) using views in presence of embedded dependencies, under bag or bag-set semantics for query evaluation.
A Strong X-Ray Flux Ratio Anomaly in the Quadruply Lensed Quasar PG 1115+080

PG 1115+080 is a quadruply lensed quasar at z = 1.72 whose image positions are well fit by simple models of the lens galaxy (at z = 0.31). At optical wavelengths, the bright close pair of images exhibits a modest flux ratio anomaly (factors of ~1.2-1.4 over the past 22 yr) with respect to these same models. We show here that as observed in X-rays with Chandra, the flux ratio anomaly is far more extreme, roughly a factor of 6. The contrasting flux ratio anomalies in the optical and X-ray band confirm the microlensing hypothesis and set a lower limit on the size of the optical continuum emission region that is ~10-100 times larger than expected from a thin accretion disk model.
On the homotopy invariance of configuration spaces

For a closed PL manifold M , we consider the conguration space F (M;k) of ordered k-tuples of distinct points in M. We show that a suitable iterated suspension of F (M;k) is a homotopy invariant of M. The number of suspensions we require depends on three parameters: the number of points k , the dimension of M and the connectivity of M.O ur proof uses a mixture of Poincar e embedding theory and berwise algebraic topology. AMS Classication 55R80; 57Q35, 55R70
Gauge fixing, zero-momentum modes and the calculation of masses on a lattice

Abstract It is shown that the zero-momentum modes can strongly affect the values of the masses, for example the magnetic screening mass m m , calculated from gauge-dependent correlators with zero momentum.
A novel reducing agent. The reduction of dicarbonyls, acyloins, alkynes, and alkenes with active uranium

Abstract Active uranium, prepared in hydrocarbon solvents from UCl 4 and [(TMEDA)Li] 2 [naphthalene] is a novel reducing agent. The unprecedented stepwise reduction of benzil and benzoin to bibenzyl has been shwon to proceed via the unsaturated species diphenylacetylene, cis -stilbene, and trans -stilbene. Active uranium also effects oligomerizations of diphenylacetylene and trans -stilbene.
International Equity Asset Classes in the Turkish Fund Industry

We examine Turkish fund portfolios and identify the role of international investments in their formation. We find that (1) Turkish funds hold a very small fraction of international assets during 1987-2008, (2) the weight of international equity in the funds with an international mandate is smaller than the total weight of domestic asset classes as of 2009, and (3) international stock holdings of Turkish portfolio managers show significant similarity, which can be explained by the fact that the managers tend to hold stocks with which they are familiar. We compare the performance of funds that have the international investment objective with benchmark portfolios and provide suggestions for more diverse funds in the Turkish fund industry.
Systematic Construction of the Equations of Motion for Multibody Systems Containing Closed Kinematic Loops

This papers presents a systematic method for deriving the minimum number of equations of motion for multibody system containing closed kinematic loops. A set of joint or natural coordinates is used to describe the configuration of the system. The constraint equations associated with the closed kinematic loops are found systematically in terms of the joint coordinates. These constraints and their corresponding elements are constructed from known block matrices representing different kinematic joints. The Jacobian matrix associated with these constraints is further used to find a velocity transformation matrix. The equations of motions are initially written in terms of the dependent joint coordinates using the Lagrange multiplier technique. Then the velocity transformation matrix is used to derive a minimum number of equations of motion in terms of a set of independent joint coordinates. An illustrative example and numerical results are presented, and the advantages and disadvantages of the method are discussed.
Application and limitations on thermal and spectroscopic methods for shelf-life prediction

In medical products, shelf-life after thermoplastic processing and sterilization is important, and ionizing radiation has become a preferred sterilization mode for medical devices. We have employed successfully thermal analytical methods to predict shelf-life for many polyolefin materials. However, as the material of construction becoming more sophisticated: multiphase alloys and blends, multi-layer constructions etc., issues existed that require clarification as to what extent these methodologies are applicable. We have employed thermal analytical methods in conjunction with spectroscopic and morphological methods to study the applicability and limitation of these techniques. Results were combined with real life and simulated aging experiments and presented in this article.
One-Pot Multicomponent Synthesis of Diversely Substituted 2-Aminopyrroles. A Short General Synthesis of Rigidins A, B, C and D

Privileged medicinal scaffolds based on the structures of tetra- and pentasubstituted 2-aminopyrroles were prepared via one-pot multicomponent reactions of structurally diverse aldehydes and N-(aryl-, hetaryl-, alkylsulfonamido)acetophenones with activated methylene compounds. This methodology was used in a four-step synthesis of alkaloids rigidins A, B, C, and D in overall yields of 61%, 58%, 60%, and 53%, respectively. Of these, rigidins B, C, and D were synthesized for the first time.
A Spectroscopic Study of HL Canis Majoris

We present optical spectroscopy of the dwarf nova HL Canis Majoris over a span of 4 years. The observations were made during standstill, outburst, and quiescence. We determine an orbital period of 0.2167867 ± 0.0000017 days, based on radial velocities determined from Hα, Hβ, and He i λ 5876 emission. We also present equivalent widths of the spectral features in outburst and in quiescence.
Three-quantifier sentences

We give a complete proof that all 3 quanti er sentences in the primitive notation of set theory (, =), are decided in , and in fact in a weak fragment of without the power set axiom. We obtain information concerning witnesses of 2 quanti er formulas with one free variable. There is a 5 quanti er sentence that is not decided in (see [2]).
Low-energy dynamics of the spinon-gauge system

Abstract The effective field theory describing the normal phase of the high-Tc cuprates is evidently not the usual Fermi liquid theory. It has been proposed that it must include a dynamically generated gauge field. Even the simplest such theory, with spinon and gauge fields only, has complicated dynamics, becoming strongly coupled at low energy. We show that in a large-n approximation the theory can be solved and has a non-trivial fixed point. Also, we find that there is no antiferromagnetic instability at weak coupling.
A Skolem–Mahler–Lech theorem in positive characteristic and finite automata

Lech proved in 1953 that the set of zeroes of a linear recurrence sequence in a field of characteristic 0 is the union of a finite set and finitely many infinite arithmetic progressions. This result is known as the Skolem–Mahler–Lech theorem. Lech gave a counterexample to a similar statement in positive characteristic. We will present some more pathological examples. We will state and prove a correct analog of the Skolem–Mahler–Lech theorem in positive characteristic. The zeroes of a recurrence sequence in positive characteristic can be described using finite automata.
'A Towering Virtue of Necessity': Interdisciplinarity and the Rise of Computer Music at Vietnam-Era Stanford

AbstractStanford, more than most American universities, transformed in the early Cold War into a research powerhouse tied to national security priorities. The budgetary and legitimacy crises that beset the military-industrial-academic research complex in the 1960s thus struck Stanford so deeply that many feared the university itself might not survive. We argue that these crises facilitated the rise of a new kind of interdisciplinarity at Stanford, as evidenced in particular by the founding of the university’s computer music center. Focusing on the “multivocal technology” of computer music, we investigate the relationships between Stanford’s broader institutional environment and the interactions among musicians, engineers, administrators, activists, and funders in order to explain the emergence of one of the most creative and profitable loci for Stanford’s contributions to industry and the arts.
Rate-Independent Constructs for Chemical Computation

This paper presents a collection of computational modules implemented with chemical reactions: an inverter, an incrementer, a decrementer, a copier, a comparator, a multiplier, an exponentiator, a raise-to-a-power operation, and a logarithm in base two. Unlike previous schemes for chemical computation, this method produces designs that are dependent only on coarse rate categories for the reactions (“fast” vs. “slow”). Given such categories, the computation is exact and independent of the specific reaction rates. The designs are validated through stochastic simulations of the chemical kinetics.