cssi/SciSciGPT-SciSciNet huggingface dataset:
Effect of nonstationarities on detrended fluctuation analysis.

Detrended fluctuation analysis ~DFA! is a scaling analysis method used to quantify long-range power-law correlations in signals. Many physical and biological signals are ‘‘noisy,’’ heterogeneous, and exhibit different types of nonstationarities, which can affect the correlation properties of these signals. We systematically study the effects of three types of nonstationarities often encountered in real data. Specifically, we consider nonstationary sequences formed in three ways: ~i! stitching together segments of data obtained from discontinuous experimental recordings, or removing some noisy and unreliable parts from continuous recordings and stitching together the remaining parts—a ‘‘cutting’’ procedure commonly used in preparing data prior to signal analysis; ~ii! adding to a signal with known correlations a tunable concentration of random outliers or spikes with different amplitudes; and ~iii! generating a signal comprised of segments with different properties—e.g., different standard deviations or different correlation exponents. We compare the difference between the scaling results obtained for stationary correlated signals and correlated signals with these three types of nonstationarities. We find that introducing nonstationarities to stationary correlated signals leads to the appearance of crossovers in the scaling behavior and we study how the characteristics of these crossovers depend on ~a! the fraction and size of the parts cut out from the signal, ~b! the concentration of spikes and their amplitudes ~c! the proportion between segments with different standard deviations or different correlations and ~d! the correlation properties of the stationary signal. We show how to develop strategies for preprocessing ‘‘raw’’ data prior to analysis, which will minimize the effects of nonstationarities on the scaling properties of the data, and how to interpret the results of DFA for complex signals with different local characteristics.
Dependence of mixed-layer entrainment on shear stress and velocity jump

From rotating-screen annulus experiments the entrainment rate, w e , normalized by the friction velocity, u * , has been found to be a function of both the overall Richardson number, R T , and the inverse Froude number, R v . The R T −½ dependence deduced by Price (1979) and Thompson (1979) satisfactorily explains the present data if multiplied by an approximate R v −1·4 dependence. The measurements indicate that R v is a variable that is influenced by side-wall friction, time after onset of the surface stress, or other factors. The greater w e / u * values of experiments of the type of Kantha, Phillips & Azad (1977) over that of the Kato & Phillips (1969) experiment can be explained by somewhat greater R v values in the latter case. A close connection is now apparent between entrainment experiments in two-layer systems designed to have only one velocity scale (the interfacial velocity jump, Δ v ), and the rotating-screen annulus experiments having two velocity scales ( u * and Δ v ). The former also have (at least) two velocity scales, the second one being associated with the presence of turbulence throughout one or both of the fluid layers. The turbulent layer is found to be quite well mixed in density only if w e / u * does not exceed about 0·03, or w e /|Δ v | does not exceed about 0·003. The present data suggest more rapid entrainment when temperature rather than salt provides the density jump, as first noted by Turner (1968) in oscillating grid experiments. If this is a Peclet-number effect, the trend did not continue for still greater P e values, the data for kaolin (clay) being very compatible with that for salt.
Algebraic K-theory and abstract homotopy theory

Abstract We decompose the K -theory space of a Waldhausen category in terms of its Dwyer–Kan simplicial localization. This leads to a criterion for functors to induce equivalences of K -theory spectra that generalizes and explains many of the criteria appearing in the literature. We show that under mild hypotheses, a weakly exact functor that induces an equivalence of homotopy categories induces an equivalence of K -theory spectra.
Solving the “Marketing Mix” Problem using Geometric Programming

This paper investigates the optimal allocation of the marketing budget within the marketing-mix decision variables so that sales or profit is maximized in a planning horizon. Since the influence of marketing mix variables upon sales are, in reality, nonlinear and interactive, a geometric programming algorithm is used that solves this problem. A procedure to estimate a functional of sales on the marketing mix and environmental variables utilizing the experienced judgments of the firm's executives and the raw data is provided. The derived functional is later optimized by the Geometric Programming algorithm under a constraint set consisting of budget and strategy restrictions imposed by a firm's marketing environment, and conditions under which the optimal solution is either local or global are identified. An empirical application for a large midwestern brewery is provided which utilizes and illustrates both the estimation an optimization procedures.
Partially awakened giants : uneven growth in China and India

The paper examines the ways in which recent economic growth has been uneven in China and India and what this has meant for inequality and poverty. Drawing on analyses based on existing household survey data and aggregate data from official sources, the authors show that growth has indeed been uneven—geographically, sectorally and at the household level—and that this has meant uneven progress against poverty, less poverty reduction than might have been achieved had growth been more balanced, and an increase in income inequality. The paper then examines why growth was uneven and why this should be of concern. The discussion is structured around the idea that there are both "good" and "bad" inequalities—drivers and dimensions of inequality and uneven growth that are good or bad in terms of what they imply for both equity and long-term growth and development. The authors argue that the development paths of both China and India have been influenced by, and have generated, both types of inequalities and that while good inequalities—most notably those that reflect the role of economic incentives—have been critical to the growth experience thus far, there is a risk that bad inequalities—those that prevent individuals from connecting to markets and limit investment and accumulation of human capital and physical capital—may undermine the sustainability of growth in the coming years. The authors argue that policies are needed that preserve the good inequalities—continued incentives for innovation and investment—but reduce the scope for bad ones, notably through investments in human capital and rural infrastructure that help the poor connect to markets.
Graphs with the Strong Havel---Hakimi Property

The Havel---Hakimi algorithm iteratively reduces the degree sequence of a graph to a list of zeroes. As shown by Favaron, Maheo, and Sacle, the number of zeroes produced, known as the residue, is a lower bound on the independence number of the graph. We say that a graph has the strong Havel---Hakimi property if in each of its induced subgraphs, deleting any vertex of maximum degree reduces the degree sequence in the same way that the Havel---Hakimi algorithm does. We characterize graphs having this property (which include all threshold and matrogenic graphs) in terms of minimal forbidden induced subgraphs. We further show that for these graphs the residue equals the independence number, and a natural greedy algorithm always produces a maximum independent set.
Induced Over-Benefiting and Under-Benefiting on the Web: Inequity Effects on Feelings and Motivations With Implications for Consumption Behavior

Inequity in its many forms has been the subject of a number of empirical research efforts. Results show that positive inequity, an over-benefited condition, and negative inequity, an under-benefited condition, have divergent effects on subsequent affects and behavioral tendencies. We embed equity treatments within a motivational structure to predict reactions to a quasi-shopping experience in which these methods operate in concert. Interaction effects—predicted by procedural justice considerations as well as instrumentally based arguments—are also tested whereby technical motivation is crossed with the equity conditions. In testing, an online experiment was created incorporating pre- and posttreatment measures. While completing a hypothetical sale, respondents received either an unanticipated, completed coupon field (the over-benefited group), an uncompleted, empty coupon field (the under-benefited group), or were not prompted with a coupon field (the control group). Results showed strong negative effects on postexposure satisfaction, intention, and desire to complete the purchase in the empty coupon field group, and similar positive effects in the completed coupon field group. Moreover, a model linking preexposure variables (expectations and technical sophistication) to postexposure measures was supported indicating carry-through effects. Lastly, procedural justice and instrumental predictions received mixed support when testing for the interaction between technical motivation and inequity. Results showed that, for those in the under-benefited group, there was only a slight tendency for those with higher levels of technical sophistication to report greater satisfaction; however a strong tendency was found for the same individuals to report a lower likelihood of completing the purchase. Implications for future research are discussed.
Network Failure Detection and Graph Connectivity

We consider a model for monitoring the connectivity of a network subject to node or edge failures. In particular, we are concerned with detecting $(\epsilon,k)$-failures: events in which an adversary deletes up to $k$ network elements (nodes or edges), after which there are two sets of nodes $A$ and $B$, each at least an $\epsilon$ fraction of the network, that are disconnected from one another. We say that a set $D$ of nodes is an $(\epsilon,k)$-detection set if, for any $(\epsilon,k)$-failure of the network, some two nodes in $D$ are no longer able to communicate; in this way, $D$ “witnesses” any such failure. Recent results show that for any graph $G$, there is an $(\epsilon,k)$-detection set of size bounded by a polynomial in $k$ and $\epsilon$, independent of the size of $G$. In this paper, we expose some relationships between bounds on detection sets and the edge-connectivity $\lambda$ and node-connectivity $\kappa$ of the underlying graph. Specifically, we show that detection set bounds can be made considerably stronger when parameterized by these connectivity values. We show that for an adversary that can delete $k \lambda$ edges, there is always a detection set of size $O(\frac{k}{\epsilon}\log\frac{1}{\epsilon})$ which can be found by random sampling. Moreover, an $(\epsilon,\lambda)$-detection set of minimum size (which is at most $\frac{1}{\epsilon}$) can be computed in polynomial time. A crucial point is that these bounds are independent not just of the size of $G$ but also of the value of $\lambda$. Extending these bounds to node failures is much more challenging. The most technically difficult result of this paper is that a random sample of $O(\frac{1}{\epsilon}\log\frac{1}{\epsilon})$ nodes is a detection set for adversaries that can delete a number of nodes up to $\kappa$, the node-connectivity. For the case of edge-failures we use VC-dimension techniques and the cactus representation of all minimum edge-cuts of a graph; for node failures, we develop a novel approach for working with the much more complex set of all minimum node-cuts of a graph.
Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Trifluoromethanesulfonate-Catalyzed Allylation of Dioxolanes

A bismuth trifluoromethanesulfonate (triflate)-catalyzed (2.0 mol-%) multicomponent reaction involving the allylation of dioxolanes followed by in situ derivatization with anhydrides to generate highly functionalized esters has been developed under solvent-free conditions. Most reagents used to date for allylation of dioxolanes are highly corrosive and are often required in stoichiometric amounts. In contrast, the use of a relatively non-toxic and non-corrosive bismuth(iii)-based catalyst makes this methodology especially attractive for scale-up.
The Economic Effects of Technological Progress: Evidence from the Banking Industry

This paper examines technological progress and its effects in the banking industry. Banks are intensive users of both IT and financial technologies, and have a wealth of data available that may be helpful for the general understanding of the effects of technological change. The research suggests improvements in costs and lending capacity due to improvements in “back-office” technologies, as well as consumer benefits from improved “front-office” technologies. The research also suggests significant overall productivity increases in terms of improved quality and variety of banking services. In addition, the research indicates that technological progress likely helped facilitate consolidation of the industry. This paper examines the available evidence on technological progress and its effects in the banking industry. Innovations in information processing, telecommunications, and related technologies—known collectively as “information technology” or “IT”—are often credited with helping fuel strong growth in the U.S. economy, although questions remain about the relative importance of IT versus other factors. The extensive research on the banking industry may help in the general understanding about the effects of technological change. The category of Depository and Nondepository Financial Institutions—of which banking is an integral part—is the most IT-intensive industry in the U.S. as measured by the ratio of computer equipment and software to value added (Triplett and Bosworth 2002, Table 2).
Wilhelm Launhardt and Bid-Rent Curves: A Note

One of the very important components in the urban and agricultural land use model is the so-called bid-rent curve. Regional and urban economists, city planners, and economic geographers have used this curve extensively as an analytical device. It is generally accepted that the explicit bid-rent function was first applied to the equilibrium of land use patterns in agricultural production by August Losch (1954) in Germany and Edgar S. Dunn (1954) in America, and was later extended by William Alonso (1964).
Survivable virtual infrastructure mapping over Transport Software-Defined Networks (T-SDN)

An algorithm is proposed to map virtual infrastructures with survivability over T-SDN for the first time. The algorithm improves the traffic-carrying capacity of networks by provisioning at least 13% more demands than the baseline algorithms.
EL ESTADO CHILENO, LOS AGENTES FISCALES Y EL TEMPRANO ORDENAMIENTO ADMINISTRATIVO DEL ESPACIO ANDINO DE LA PROVINCIA DE TARAPACÁ (1880-1930)

En la decada de 1880, una vez afianzada la anexion territorial de Tarapaca, Chile se aboco a su ordenamiento politico-administrativo. Bajo este contexto, y tomando como base registros encontrados en los archivos de la Intendencia de Tarapaca ubicados en Iquique y en Santiago, en este trabajo se sostiene que la conjuncion de los intereses salitreros rentistas con los lineamientos modernizadores llevo a que, entre las decadas de 1880 y 1930, el Estado chileno tuviera un comportamiento marcadamente distante respecto a los recursos, la poblacion y el espacio andino de Tarapaca, lo que se reflejo en una escasa presencia del aparato fiscal como en la ausencia de una politica de chilenizacion especifica.
Trellis termination of Multi-h CPM and the Diophantine Frobenius Problem

This paper presents a method for terminating the phase trellis in Multi-h Continuous Phase modulation (CPM). It is shown that tilted phase trellis for a Multi-h CPM signal is periodic and enables the representation of the modulator as the cascade of a periodic recursive continuous phase encoder (CPE) and a phase modulator (PM). We then pose the problem of finding the number of symbols that will terminate the tilted phase trellis, and establish a connection of its solution to the Diophantine Frobenius Problem (FP). Results are derived for the existence of a terminating sequence (TS), and bounds are established on its length in terms of the modulation parameters.
A phase transition behavior for Brownian motions interacting through their ranks

Consider a time-varying collection of n points on the positive real axis, modeled as Exponentials of n Brownian motions whose drift vector at every time point is determined by the relative ranks of the coordinate processes at that time. If at each time point we divide the points by their sum, under suitable assumptions the rescaled point process converges to a stationary distribution (depending on n and the vector of drifts) as time goes to infinity. This stationary distribution can be exactly computed using a recent result of Pal and Pitman. The model and the rescaled point process are both central objects of study in models of equity markets introduced by Banner, Fernholz, and Karatzas. In this paper, we look at the behavior of this point process under the stationary measure as n tends to infinity. Under a certain ‘continuity at the edge’ condition on the drifts, we show that one of the following must happen: either (i) all points converge to 0, or (ii) the maximum goes to 1 and the rest go to 0, or (iii) the processes converge in law to a non-trivial Poisson–Dirichlet distribution. The underlying idea of the proof is inspired by Talagrand’s analysis of the low temperature phase of Derrida’s Random Energy Model of spin glasses. The main result establishes a universality property for the BFK models and aids in explicit asymptotic computations using known results about the Poisson–Dirichlet law.
Grounded semantic composition for visual scenes

We present a visually-grounded language understanding model based on a study of how people verbally describe objects in scenes. The emphasis of the model is on the combination of individual word meanings to produce meanings for complex referring expressions. The model has been implemented, and it is able to understand a broad range of spatial referring expressions. We describe our implementation of word level visually-grounded semantics and their embedding in a compositional parsing framework. The implemented system selects the correct referents in response to natural language expressions for a large percentage of test cases. In an analysis of the system's successes and failures we reveal how visual context influences the semantics of utterances and propose future extensions to the model that take such context into account.
Electrical critical dimension metrology for 100-nm linewidths and below

In this paper, we have demonstrated an electrical CD process capable of resolving linewidth swell below 100 nm compatible with a standard polysilicon patterning flow. Appropriate selection of dopant species combined with a reduction in anneal temperature were in the primary means for achieving a physical to electrical linewidth bias of 20 nm. These findings supported our hypothesis that dopant our-diffusion was the primary source of the bias. Also, ECD metrology is applied to quantifying poly CD variations in the presence of substrate topography.
TrustDavis: a non-exploitable online reputation system

We present TrustDavis, an online reputation system that provides insurance against trade fraud by leveraging existing relationships between players, such as the ones present in social networks. Using TrustDavis and a simple strategy, an honest player can set an upper bound on the losses caused by any malicious collusion of players. In addition, TrustDavis incents participants to accurately rate each other, resists participants' pseudonym changes, and is inherently distributed.
A Compact Acoustic Recorder

Abstract : This paper discusses the design and operation of a portable compact acoustic recorder. Designed to be used in arctic conditions for applications that require portable equipment, the device is configured to fit into a lightweight briefcase. It will operate for eight hours at -40 F with heat provided by a hot water bottle. It has proven to be an effective scientific tool in the measurement of underwater acoustic signals in arctic experiments. It has also been used successfully in warmer climates, e.g., in recording acoustic signals from small boats with no AC power. The acoustic recorder's cost is moderate since it is based on a Sony Walkman Professional (WM-D6C) tape recorder playback unit. A speaker and battery assembly and a hydrophone interface electronic assembly complete the system electronics. The interface assembly supplies a number of functions, including a calibration tone generator, an audio amplifier, and a hydrophone interface. Calibrated acoustic recordings can be made by comparing the calibration tone amplitude with the acoustic signal amplitude. The distortion of the recording is minimized by using a high quality, consumer tape recorder.
Making sense out of massive data by going beyond differential expression

With the rapid growth of publicly available high-throughput transcriptomic data, there is increasing recognition that large sets of such data can be mined to better understand disease states and mechanisms. Prior gene expression analyses, both large and small, have been dichotomous in nature, in which phenotypes are compared using clearly defined controls. Such approaches may require arbitrary decisions about what are considered “normal” phenotypes, and what each phenotype should be compared to. Instead, we adopt a holistic approach in which we characterize phenotypes in the context of a myriad of tissues and diseases. We introduce scalable methods that associate expression patterns to phenotypes in order both to assign phenotype labels to new expression samples and to select phenotypically meaningful gene signatures. By using a nonparametric statistical approach, we identify signatures that are more precise than those from existing approaches and accurately reveal biological processes that are hidden in case vs. control studies. Employing a comprehensive perspective on expression, we show how metastasized tumor samples localize in the vicinity of the primary site counterparts and are overenriched for those phenotype labels. We find that our approach provides insights into the biological processes that underlie differences between tissues and diseases beyond those identified by traditional differential expression analyses. Finally, we provide an online resource (http://concordia.csail.mit.edu) for mapping users’ gene expression samples onto the expression landscape of tissue and disease.
Stability of a strongly-attractive, two-component Fermi gas

Summary form only given. Using a simple model, we show that a strongly-attractive, two-component Fermi gas of atoms should be mechanically stable as a consequence of unitarity. We demonstrate this stability experimentally in a degenerate gas of /sup 6/Li atoms.
Phase-domain all-digital phase-locked loop

A fully digital frequency synthesizer for RF wireless applications has recently been proposed. At its foundation lies a digitally controlled oscillator that deliberately avoids any analog tuning controls. When implemented in a digital deep-submicrometer CMOS process, the proposed architecture appears more advantageous over conventional charge-pump-based phase-locked loops (PLLs), since it exploits signal processing capabilities of digital circuits and avoids relying on the fine voltage resolution of analog circuits. An actual implementation of an all-digital PLL (ADPLL)-based local oscillator and transmitter used in a commercial 0.13-/spl mu/m CMOS single-chip Bluetooth radio has recently been disclosed. The conventional phase/frequency detector, charge pump and RC loop filter are replaced by a time-to-digital converter and a simple digital loop filter. Due to the lack of the correlational phase detection mechanism, the loop does not contribute to the reference spurs. The measured close-in phase noise of -86 dBc/Hz is adequate even for Global System for Mobile communications (GSM) applications. In this paper, we present the mathematical description and operational details of the phase-domain ADPLL.
Dispersion and betatron function correction in the Advanced Photon Source storage ring using singular value decomposition

Magnet errors and off-center orbits through sextupoles perturb the dispersion and beta functions in a storage ring (SR), which affects machine performance. In a large ring such as the Advanced Photon Source (APS), the magnet errors are difficult to determine with beam-based methods. Also the non-zero orbit through sextupoles result from user requests for steering at light source points. For expediency, a singular value decomposition (SVD) matrix method analogous to orbit correction was adopted to make global corrections to these functions using strengths of several quadrupoles as correcting elements. The direct response matrix is calculated from the model of the perfect lattice. The inverse is calculated by SVD with a selected number of singular vectors. Resulting improvement in the lattice functions and machine performance are presented.
Simulation of Respiratory Regulation of Blood Gases in the Critically Ill Patient

In the regulation of arterial blood gases, the relative importance of metabolic exchange, respiratory capability, and level of ventilatory control sensitivity to blood O2 , CO2 and pH was investigated. The study was based on a dynamic computer simulation of a multi-compartment elastic lung and its interactions with the cardiorespiratory system, and the regulation of acid/base balance. The model was evaluated with clinical data from control and critically ill patients. This study suggests that increases in metabolic demand and reduced ventilatory capability are major factors in influencing the regulation of arterial gas tensions and pH in patients with severe sepsis, rather than changes in the level of sensitivity to arterial CO2 and O2 .
Motion estimation with quadtree splines

This paper presents a motion estimation algorithm based on a new multiresolution representation, the quadtree spline. This representation describes the motion field as a collection of smoothly connected patches of varying size, where the patch size is automatically adapted to the complexity of the underlying motion. The topology of the patches is determined by a quadtree data structure, and both split and merge techniques are developed for estimating this spatial subdivision. The quadtree spline is implemented using another novel representation, the adaptive hierarchical basis spline, and combines the advantages of adaptively-sized correlation windows with the speedups obtained with hierarchical basis preconditioners. Results are presented on some standard motion sequences.
Measurement of machine performance degradation using a neural network model

Abstract Machines degrade as a result of aging and wear, which decreases performance reliability and increases the potential for faults and failures. The impact of machine faults and failures on factory productivity is an important concern for manufacturing industries. Economic impacts relating to machine availability and reliability, as well as corrective (reactive) maintenance costs, have prompted facilities and factories to improve their maintenance techniques and operations to monitor machine degradation and detect faults. This paper presents an innovative methodology that can change maintenance practice from that of reacting to breakdowns, to one of preventing breakdowns, thereby reducing maintenance costs and improving productivity. To analyze the machine behavior quantitatively, a pattern discrimination model (PDM) based on a cerebellar model articulation controller (CMAC) neural network was developed. A stepping motor and a PUMA 560 robot were used to study the feasibility of the developed technique. Experimental results have shown that the developed technique can analyze machine degradation quantitatively. This methodology could help operators set up machines for a given criterion, determine whether the machine is running correctly, and predict problems before they occur. As a result, maintenance hours could be used more effectively and productively.
A multiple discrete-continuous model for independent- and joint-discretionary-activity participation decisions

This paper presents a multiple discrete-continuous econometric structure to model the daily time-investment decisions of couples in solo- and joint-discretionary activities incorporating intra-personal and inter-personal inter-dependencies. The empirical model was estimated using data from the 2000 Bay Area Travel Survey. The results indicate evidence of the positive impact of vehicle availability on independent activity participation and the negative impacts of the presence of children and mandatory time investments on the joint discretionary-activity engagement of the spouses. In addition, we also find the mandatory- and maintenance-activity-participation characteristics of the spouse to influence the discretionary activity choices of individuals. Finally, the analysis also indicates a strong impact of common unobserved factors on the decisions of couples. From a policy analysis perspective, these results imply that demand-management actions directly impacting one adult could also result in changes to the activity patterns of his/her spouse and to changes in joint activity participation characteristics.
Rational surface maps with invariant meromorphic two-forms

Let $$f:S\dashrightarrow S$$ be a rational self-map of a smooth complex projective surface $$S$$ and $$\eta $$ be a meromorphic two-form on $$S$$ satisfying $$f^*\eta = \delta \eta $$ for some $$\delta \in \mathbf {C}^*$$ . We show that under a mild topological assumption on $$f$$ , there is a birational change of domain $$\psi : X\dashrightarrow S$$ such that $$\psi ^*\eta $$ has no zeros. In this context, we investigate the notion of algebraic stability for $$f$$ , proving that $$f$$ can be made algebraically stable if and only if it acts nicely on the poles of $$\eta $$ . We illustrate this last result in the case $$\eta = \frac{dx\wedge dy}{xy}$$ , where we translate our stability result into a condition on whether a circle homeomorphism associated to $$f$$ has rational rotation number.
Financial markets, specialization, and learning by doing

Abstract This paper considers three questions: (1) what is the role of financial markets in development, (2) why do some economies have such poorly developed financial markets, and (3) can government policy be used to promote financial market development? With respect to the first question, we formalize the widely-held notion that financial markets promote entrepreneurship, specialization, and learning-by-doing. However, if economic incentives for specialization are absent, financial markets may fail to form. This occurs when real interest rates are too low. We also discuss policies that can be used to promote financial market development. When these policies are successful, they will be growth promoting. Finally, we examine policies intended to manipulate returns on savings, which are often important components of “financial liberalizations”. We describe conditions under which such policies will be conducive to growth.
Weak Galerkin methods for second order elliptic interface problems

Weak Galerkin methods refer to general finite element methods for partial differential equations (PDEs) in which differential operators are approximated by their weak forms as distributions. Such weak forms give rise to desirable flexibilities in enforcing boundary and interface conditions. A weak Galerkin finite element method (WG-FEM) is developed in this paper for solving elliptic PDEs with discontinuous coefficients and interfaces. Theoretically, it is proved that high order numerical schemes can be designed by using the WG-FEM with polynomials of high order on each element. Extensive numerical experiments have been carried out to validate the WG-FEM for solving second order elliptic interface problems. High order of convergence is numerically confirmed in both L 2 and L ∞ norms for the piecewise linear WG-FEM. Special attention is paid to solve many interface problems, in which the solution possesses a certain singularity due to the nonsmoothness of the interface. A challenge in research is to design nearly second order numerical methods that work well for problems with low regularity in the solution. The best known numerical scheme in the literature is of order O ( h ) to O ( h 1.5 ) for the solution itself in L ∞ norm. It is demonstrated that the WG-FEM of the lowest order, i.e., the piecewise constant WG-FEM, is capable of delivering numerical approximations that are of order O ( h 1.75 ) to O ( h 2 ) in the L ∞ norm for C 1 or Lipschitz continuous interfaces associated with a C 1 or H 2 continuous solution.
Public key cryptography sans certificates in ad hoc networks

Several researchers have proposed the use of threshold cryptographic model to enable secure communication in ad hoc networks without the need of a trusted center. In this model, the system remains secure even in the presence of a certain threshold t of corrupted/malicious nodes. In this paper, we show how to perform necessary public key operations without node-specific certificates in ad hoc networks. These operations include pair-wise key establishment, signing, and encryption. We achieve this by using Feldman's verifiable polynomial secret sharing (VSS) as a key distribution scheme and treating the secret shares as the private keys. Unlike in the standard public key cryptography, where entities have independent private/public key pairs, in the proposed scheme the private keys are related (they are points on a polynomial of degree t) and each public key can be computed from the public VSS information and node identifier. We show that such related keys can still be securely used for standard signature and encryption operations (using resp. Schnorr signatures and ElGamal encryption) and for pairwise key establishment, as long as there are no more that t collusions/corruptions in the system. The proposed usage of shares as private keys can also be viewed as a threshold-tolerant identity-based cryptosystem under standard (discrete logarithm based) assumptions.
The Case for Animal Rights

I regard myself as an advocate of animal rights—as part of the animal rights movement. That movement, as I conceive it, is committed to a number of goals, including: the total abolition of the use of animals in science; the total dissolution of commercial animal agriculture; the total elimination of commercial and sport hunting and trapping.
Implications for the Yen of Japanese Current Account Adjustment

This paper presents a quantitative evaluation of the effect on the yen of some alternative scenarios under which Japan reaches current account balance. The analytical framework is a global general-equilibrium model, based closely on Obstfeld and Rogoff (2005a, 2005b), within which relative prices clear the world markets for traded goods as well as the domestic markets for nontraded goods. Depending on assumptions about the critical substitution elasticities underlying the model, the yen could appreciate by as much as 10 per cent for each 1 percent of GDP reduction in its current account surplus. The effect would be smaller if substitution elasticities are larger, or if adjustment is accompanied by an expansion of Japanese nontradable output, the latter presumably implied by a return to a more efficient level of labor utilization.
Adaptive satellite attitude control in the presence of inertia and CMG gimbal friction uncertainties

A nonlinear adaptive attitude controller is designed in this paper that compensates for dynamic uncertainties in the spacecraft inertia matrix and unknown dynamic and static friction effects in the control moment gyroscope (CMG) gimbals. Attitude control torques are generated by means of a four single gimbal CMG pyramid cluster. The challenges to develop the adaptive controller are that the control input is multiplied by uncertainties due to dynamic friction effects and is embedded in a discontinuous nonlinearity due to static friction effects. A uniformly ultimately bounded result is proven via Lyapunov analysis for the case in which both static and dynamic gimbal friction is included in the dynamic model, and an extension is provided that illustrates how asymptotic tracking is achieved when only dynamic friction is present in the CMG model.
Monetary Policy Rules, Macroeconomic Stability, and Inflation: A View from the Trenches

I estimate a forward-looking monetary policy reaction function for the Federal Reserve for the periods before and after Paul Volcker’s appointment as Chairman in 1979, using information that was available to the FOMC in real time from 1966 to 1995. The results suggest broad similarities in policy and point to a forward-looking approach to policy consistent with a strong reaction to inflation forecasts during both periods. This contradicts the hypothesis, based on analysis with ex post constructed data, that the instability of the Great Inflation was the result of weak FOMC policy responses to expected inflation. A difference is that prior to Volcker’s appointment, policy was too activist in reacting to perceived output gaps that retrospectively proved overambitious. Drawing on contemporaneous accounts of FOMC policy, I discuss the implications of the findings for alternative explanations of the Great Inflation and the improvement in macroeconomic stability since then.
Phase Equilibria in the Systems CaO–CuO and CaO‐Bi2O3

New data are presented on the phase equilibria of the binary systems CaO-CuO and CaO-Bi2O3. Corrected compositions are reported for Ca.Bi6O13 and Ca2Bi2O5 and a new metastable high-temperature phase is reported for a composition near Ca6Bi7O16.5. The composition and decomposition temperatures for Ca1–x.CuO2 are given for both air and 1 atm of oxygen at 755 ± 5° and 835 ± 5°C, respectively.
Ion concentration dynamics as a mechanism for neuronal bursting

We describe a simple conductance-based model neuron that includes intra- and extracellular ion concentration dynamics and show that this model exhibits periodic bursting. The bursting arises as the fast-spiking behavior of the neuron is modulated by the slow oscillatory behavior in the ion concentration variables and vice versa. By separating these time scales and studying the bifurcation structure of the neuron, we catalog several qualitatively different bursting profiles that are strikingly similar to those seen in experimental preparations. Our work suggests that ion concentration dynamics may play an important role in modulating neuronal excitability in real biological systems.
Tug-of-War and Infinity Laplace Equation with Vanishing Neumann Boundary Condition

We study a version of the stochastic “tug-of-war” game, played on graphs and smooth domains, with the empty set of terminal states. We prove that, when the running payoff function is shifted by an appropriate constant, the values of the game after n steps converge in the continuous case and the case of finite graphs with loops. Using this we prove the existence of solutions to the infinity Laplace equation with vanishing Neumann boundary condition.
Synthetic studies on spinosyn A. Convenient enantioselective construction of a suitably functionalized trans,anti,cis-decahydro-as-indacene intermediate via [3.3] sigmatropy and double configurational inversion

Abstract An enantioselective route to the decahydro-as-indacene15 is described. Anionic oxy-Cope rearrangement of alcohol 5 initiates the sequence, which capitalizes on thermodynamics to control ultimate elaboration of the four key stereogenic centers resident in the several intermediates.
Total Synthesis of Piericidin A1 and B1

The first total syntheses of piericidin A1 and B1 are disclosed and unambiguously establish the relative and absolute stereochemistry of the natural products by an approach that will facilitate the synthesis of a series of analogues. Central to the approach is an inverse electron demand Diels−Alder reaction of a N-sulfonyl-1-aza-1,3-butadiene with tetramethoxyethene followed by Lewis acid-promoted aromatization used to assemble the functionalized pyridine core. Additional key elements in the convergent approach include the use of an anti-aldol reaction to install the C9 and C10 relative and absolute stereochemistry, a modified Julia olefination for formation of the C5−C6 trans double bond with convergent assemblage of the side chain, and a penultimate heterobenzylic Stille cross-coupling reaction of the pyridyl core with the fully elaborated side chain.
Motherhood Delay and the Human Capital of the Next Generation

This paper uses biological fertility shocks as instrumental variables to estimate the causal effect of motherhood delay on the cognitive ability of first children. Maternal age at first birth represents a potential determinant of early human capital formation that reflects choices that respond to financial incentives, cultural norms, and policy environment. The key measures of cognitive ability are Peabody Individual Achievement Test (PIAT) scores. Test scores have long been predictors of individual educational attainment and earn ings, and their importance has only increased (Richard Murnane, John Willet, and Frank Levy 1995). At the national level, test perfor mance in mathematics and science is strongly related to economic growth, and may matter more than years of completed schooling (Eric Hanushek and Dennis Kimko 2000). Using data on first-born children age 5 to 14 in the National Longitudinal Survey of Youth 1979 (NLSY79) Children survey, this paper finds delayed moth erhood leads to significant increases in PIAT test scores. The relationship is robust to the inclusion of various controls for observable ele
Meixner polynomials of the second kind and quantum algebras representing su(1, 1)

We show how Viennot’s combinatorial theory of orthogonal polynomials may be used to generalize some recent results of Sukumar and Hodges (Hodges & Sukumar 2007 Proc. R. Soc. A 463 , 2401–2414 ([doi:10.1098/rspa.2007.0001][1]); Sukumar & Hodges 2007 Proc. R. Soc. A 463 , 2415–2427 ([doi:10.1098/rspa.2007.0003][2])) on the matrix entries in powers of certain operators in a representation of su(1, 1). Our results link these calculations to finding the moments and inverse polynomial coefficients of certain Laguerre polynomials and Meixner polynomials of the second kind. As an immediate consequence of results by Koelink, Groenevelt and Van Der Jeugt (Van Der Jeugt 1997 J. Math. Phys. 38 , 2728–2740 ([doi:10.1063/1.531984][3]); Koelink & Van Der Jeugt 1998 SIAM J. Math. Anal. 29 , 794–822 ([doi:10.1137/S003614109630673X][4]); Groenevelt & Koelink 2002 J. Phys. A 35 , 65–85 ([doi:10.1088/0305-4470/35/1/306][5])), for the related operators, substitutions into essentially the same Laguerre polynomials and Meixner polynomials of the second kind may be used to express their eigenvectors. Our combinatorial approach explains and generalizes this ‘coincidence’. [1]: http://dx.doi.org/doi:10.1098/rspa.2007.0001 [2]: http://dx.doi.org/doi:10.1098/rspa.2007.0003 [3]: http://dx.doi.org/doi:10.1063/1.531984 [4]: http://dx.doi.org/doi:10.1137/S003614109630673X [5]: http://dx.doi.org/doi:10.1088/0305-4470/35/1/306
Line-drawing interpretation: a mathematical framework

The author reports on the progress toward a mathematical theory of line-drawing interpretation. A working framework is developed, and a variety of tools and techniques are demonstrated within it. He reviews related work and discusses his assumptions. He presents a projective mapping which he expects will find use in the extension of results derived for orthographic projection to perspective projection. H. Whitney's definition (1955) of an excellent mapping is reviewed and it is shown that both orthographic and perspective projections of piecewise C/sup 3/ surfaces are excellent under general viewpoint. It is thus demonstrated that there are only two types of local singularities, folds and cusps, associated with the projection of a C/sup 3/ surface. The results render unnecessary the assumption of stability under perturbation of the viewed surface, which was required in previous work based on Whitney's results. The modes of interaction between viewpoint-independent and viewpoint-dependent edges are dealt with and the continuity constraints imposed on the scene by its line drawing investigated. >
Generalized 1-Skeleta and a Lifting Result

Guillemin and Zara (Duke Math J 107(2):283–349, 2001) described an analogue of Morse theory on a certain class of 1-skeleta including all those coming from simple polytopes. In this paper we extend the methods of Guillemin and Zara to a larger class of 1-skeleta including all those coming from simple polytopes and their 1-skeleton projections. As an application of these methods we prove a lifting result which yields an intrinsic characterization of 1-skeleton projections of simple polytopes.
Involvement of purinergic P2X4 receptors in alcohol intake of high-alcohol-drinking (HAD) rats

Background The P2X4 receptor (P2X4R) is thought to be involved in regulating alcohol-consuming behaviors, and ethanol (EtOH) has been reported to inhibit P2X4Rs. Ivermectin is an antiparasitic agent that acts as a positive allosteric modulator of the P2X4R. This study examined the effects of systemically and centrally administered ivermectin on alcohol drinking of replicate lines of high-alcohol-drinking (HAD-1/HAD-2) rats, and the effects of lentiviral-delivered short-hairpin RNAs (shRNAs) targeting P2rx4 on EtOH intake of female HAD-2 rats. Methods For the first experiment, adult male HAD-1 and HAD-2 rats were given 24-hour free-choice access to 15% EtOH versus water. Dose–response effects of ivermectin (1.5 to 7.5 mg/kg, intraperitoneally [i.p.]) on EtOH intake were determined; the effects of ivermectin were then examined for 2% w/v sucrose intake over 5 consecutive days. In the second experiment, female HAD-2 rats were trained to consume 15% EtOH under 2-hour limited access conditions, and dose–response effects of intracerebroventricular (ICV) administration of ivermectin (0.5 to 2.0 μg) were determined over 5 consecutive days. The third experiment determined the effects of microinfusion of a lentivirus expressing P2rx4 shRNAs into the posterior ventral tegmental area (VTA) on 24-hour EtOH free-choice drinking of female HAD-2 rats. Results The highest i.p. dose of ivermectin reduced alcohol drinking (30 to 45%) in both rat lines, but did not alter sucrose intake. HAD-2 rats appeared to be more sensitive than HAD-1 rats to the effects of ivermectin. ICV administration of ivermectin reduced 2-hour limited access intake (~35%) of female HAD-2 rats; knockdown of P2rx4 expression in the posterior VTA reduced 24-hour free-choice EtOH intake (~20%). Conclusions Overall, the results of this study support a role for P2X4Rs within the mesolimbic system in mediating alcohol-drinking behavior.