cssi/SciSciGPT-SciSciNet huggingface dataset:
Improved linear response for stochastically driven systems

The recently developed short-time linear response algorithm, which predicts the average response of a nonlinear chaotic system with forcing and dissipation to small external perturbation, generally yields high precision of the response prediction, although suffers from numerical instability for long response times due to positive Lyapunov exponents. However, in the case of stochastically driven dynamics, one typically resorts to the classical fluctuation-dissipation formula, which has the drawback of explicitly requiring the probability density of the statistical state together with its derivative for computation, which might not be available with sufficient precision in the case of complex dynamics (usually a Gaussian approximation is used). Here, we adapt the short-time linear response formula for stochastically driven dynamics, and observe that, for short and moderate response times before numerical instability develops, it is generally superior to the classical formula with Gaussian approximation for both the additive and multiplicative stochastic forcing. Additionally, a suitable blending with classical formula for longer response times eliminates numerical instability and provides an improved response prediction even for long response times.
An unprecedented uranyl phosphate framework in the structure of [(UO2)3(PO4)O(OH)(H2O)2](H2O).

The new uranyl phosphate [(UO2)3(PO4)O(OH)(H2O)2] (H2O) (1) with an unprecedented framework structure has been synthesized at 150 and 185 °C. The structure (tetragonal, P42/mbc, a = 14.015(1) A, c = 13.083(2) A, V = 2575.6(4) A3, Z = 8) contains uranyl phosphate chains composed of uranyl pentagonal and hexagonal bipyramids and phosphate tetrahedra linked by sharing of polyhedral edges. The uranyl phosphate chains are aligned both along [100] and [010] and are linked into a novel framework structure involving channels along [001]. Topologically identical chains occur linked into sheets in more than a dozen uranyl phosphate minerals, but these chains have never been observed in opposing orientations and linked into a framework as in 1.
Morning Commute in a Single-Entry Traffic Corridor with No Late Arrivals

This paper analyzes a model of early morning traffic congestion, that is a special case of the model considered in Newell (1988). A fixed number of identical vehicles travel along a single-lane road of constant width from a common origin to a common destination, with LWR flow congestion and Greenshields’ Relation. Vehicles have a common work start time, late arrivals are not permitted, and trip cost is linear in travel time and time early. The paper explores traffic dynamics for the Social Optimum, in which total trip cost is minimized, and for the User Optimum, in which no vehicle’s trip cost can be reduced by altering its departure time. Analytical and, when possible, closed-form solutions are presented, along with numerical examples.
Freedom of Navigation Assertions: The United States as the World’s Policeman

In line with its “Freedom of Navigation” program, the United States conducts “operational assertions” by sending naval vessels to violate what it considers to be the excessive maritime claims of other states. Efforts have been made to legitimate this program to the public and elected officials on both liberal and realist grounds: Freedom of navigation is an important component of the liberal international order while also central to the exercise of U.S. naval power. However, it does not follow that military assertions, which create a security risk and are inconsistent with liberal principles, should take precedence over diplomatic and multilateral steps. Rather, the program has faced little scrutiny to date due to its relative obscurity.
Growth by Destination (Where You Export Matters): Trade with China and Growth in African Countries*

I perform Arellano-Bond GMM estimations using panel data over the period 1995-2008 and explore the growth effects of Africa’s trade with China, distinguishing between the effect of imports and the effect of exports, and controlling for the role of export concentration. Four important results are obtained from the empirical analysis. First, there is no empirical evidence that exports to China enhance growth unconditionally. Second, the results suggest that export concentration enhances the growth effects of exporting to China, implying that countries which export one major commodity to China benefit more (in terms of growth) than do countries that have more diversified exports. Third, contrary to the widely held view that increasing imports from China would have a negative effect, the empirical results show that the share of China in a country’s total imports has a robust positive effect on growth. Finally, the evidence suggests that there is an inverted-U relationship between exports to developed countries and growth in Africa. Overall, the results seem to provide support for the hypothesis of growth by destination (i.e., that where a country exports matters for the exporting country’s growth and development). I draw on these findings to outline some policy implications.
Experimental Series on Behavior of Post-Damage Recollected Material

Summary form only given. Spallation damage, a typical method of failure for ductile materials, results from the nucleation, growth and coalescence of voids caused by high tensile stress. Specific areas of research on spallation damage include the damage initiation regime in convergent geometry, behavior of material recollected after damage, and effects of convergent geometry (shear stresses, etc.) on the material response. Currently, models of spallation phenomena are typically based on experiments using a planar configuration, where a significant body of data exists from gas gun, laser and high-explosive experiments. Planar experiments allow for one-dimensional analysis of the evolution of failure characteristics. Using a cylindrical configuration to study spallation damage, however, requires the consideration of physical effects not present in the planar configuration. Cylindrical experiments allow for a careful analysis of the effect of convergence and two-dimensional strains and shear stresses on the spallation profile of a material. These experiments challenge existing computational material models and databases and provide motivation to improve these models and increase the predictive capabilities of codes. A series of experiments (R-Damage-0, -1 and -2) previously provided data about failure initiation of a well-characterized material (aluminum) in a cylindrical geometry. This presentation will cover the theory, design and results for the next series of experiments (R-Damage-3, -4 and -5), which studied the behavior of material recollected after damage from pressures in the damage initiation regime.
Piezoelectric micromotors for microrobots

The authors have begun research into piezoelectric ultrasonic motors using ferroelectric thin films. The authors have fabricated the stator components of these millimeter diameter motors on silicon wafers. Ultrasonic motors consist of two pieces: a stator and a rotor. The stator includes a piezoelectric film in which bending is induced in the form of a traveling wave. A small glass lens placed upon the stator becomes the spinning rotor. Piezoelectric micromotors overcome the problems currently associated with electrostatic micromotors such as low torque, friction, and the need for high voltage excitation. More importantly, they may offer a much simpler mechanism for coupling power out. Using thin films of lead zirconate titanate on silicon nitride membranes, various types of actuator structures can be fabricated. By combined new robot control systems with piezoelectric motors and micromechanics, the authors propose creating micromechanical systems that are small, cheap and completely autonomous. >
Person Tracking in UAV Video

The UAV person tracking task for this evaluation was particularly difficult because of large, complicated, and low-quality videos, with only small images of people. We found that our best results were obtained using a combination of intensity thresholding (for IR imagery), motion compensation, interest-point detection and correspondence, and pattern classification. This can be considered a preliminary exploration into an extremely challenging problem.
Regiodivergent and Stereoselective Hydrosilylation of 1,3-Disubstituted Allenes†

Methods for the highly stereoselective and regiodivergent hydrosilylation of 1,3-disubstituted allenes have been developed. The synthesis of E allylsilanes is accomplished with palladium NHC catalysts, and trisubstituted Z alkenylsilanes are accessed with nickel NHC catalysts. Unsymmetrically substituted allenes are well tolerated with nickel catalysis and afford Z alkenylsilanes. Evidence for a plausible mechanism was obtained through an isotopic double-labeling crossover study.
A Novel Method for Instantaneous, Quantitative Measurement of Molecular Mixing in Gaseous Flows

We describe a novel method for making in- stantaneous, quantitative, planar measurements of fluid mixed at the molecular level in gaseous flows. The method relies on the effective oxygen quenching of the phospho- rescence of luminescent tracers, such as acetone and bi- acetyl. The tracer's fluorescence emission is used to obtain information about the passive scalar, regardless of its molecular mixing state, whereas the phosphorescence emission from the same tracer displays mixing-state-de- pendant behavior and reveals the presence of molecularly unmixed fluid. By combining the information from both fluorescence and phosphorescence signals, the instanta- neous, quantitative measurements of molecularly mixed fluid fraction can be obtained at each pixel of the detector. This method accomplishes the same objectives as previous dual-tracer LIF methods, but with a single tracer and a much-reduced burden on the instrumentation and the experimental setup. The new technique is demonstrated in a study of mixing in a forced acetone-seeded nitrogen jet discharging into ambient air. The instantaneous spatial maps of molecularly mixed jet fluid fraction and jet fluid mixing efficiency are presented. The capability of the present technique to identify stirring at sub-resolution scale is also demonstrated.
Power Combining in an Array of Microwave Power Rectifiers

Microwave power rectifiers have been developed previously with greater than 85-percent RF-to-dc conversion efficiency. To obtain useful power levels for proposed free-space microwave power transmission applications, numerous rectifier outputs are interconnected in series and/or parallel to share a common dc load. This work analyzes the resultant efficiency degradation when identical rectifiers operate at different RF power Ievels as caused by the power beam taper. Both a closed-form analytical circuit model and a detailed computer-simulation model are used to obtain the output dc load line of the rectifier. The efficiency degradation is nearly identical with series and parallel combining, and the closed-form analytical model provides results which are similar to the detailed computer-simulation model.
Attitude tracking with adaptive rejection of rate gyro disturbances

The classical attitude control problem for a rigid body is revisited under the assumption that measurements of the angular rates obtained by means of rate gyros are corrupted by harmonic disturbances, a setup of importance in several aerospace applications. The paper extends previous methods developed to compensate bias in angular rate measurements by accounting for a more general class of disturbances, and by allowing uncertainty in the inertial parameters. By resorting to adaptive observers designed on the basis of the internal model principle, it is shown how converging estimates of the angular velocity can be obtained, and used effectively in a passivity-based certainty-equivalence controller yielding global convergence within the chosen parametrization of the group of rotations. Since a persistence of excitation condition is not required for the convergence of the state estimates, only an upper bound on the number of distinct harmonic components of the disturbance is needed for the applicability of the method.
WordNet::Similarity: measuring the relatedness of concepts

WordNet::Similarity is a freely available software package that makes it possible to measure the semantic similarity and relatedness between a pair of concepts (or synsets). It provides six measures of similarity, and three measures of relatedness, all of which are based on the lexical database WordNet. These measures are implemented as Perl modules which take as input two concepts, and return a numeric value that represents the degree to which they are similar or related.
PHYSICAL INTERPRETATION OF CERTAIN STRONG COUPLING SINGULARITIES

We interpret certain strong coupling singularities of the E8×E8 heterotic string on K3 in terms of exotic six-dimensional theories in which E8 is a gauge symmetry. These theories are closely related to theories obtained at small instanton singularities, which have E8 as a global symmetry.
Pork versus public goods: an experimental study of public good provision within a legislative bargaining framework

We experimentally investigate a legislative bargaining model with both public and particularistic goods. Consistent with the qualitative implications of the model: there is near exclusive public good provision in the pure public good region, in the pure private good region minimum winning coalitions sharing private goods predominate, and in the “mixed” region proposers generally take some particularistic goods for themselves, allocating the remainder to public goods. As in past experiments, proposer power is not nearly as strong as predicted, resulting in public good provision decreasing in the mixed region as its relative value increases, which is inconsistent with the theory.
Coupled noise predictors for lossy interconnects

Closed form expressions for the near and far end noise of a coupled 2-line transmission structure with resistive losses have been developed for implementation in coupled noise checking software. Criteria have been defined to quantify the error of these predictors, which is shown through extensive comparisons to simulation results to be quite good over a wide range of transmission line losses. A design curve is also presented and defines the region of validity for these predictors. >
Attitudes toward Highly Skilled and Low-skilled Immigration: Evidence from a Survey Experiment

Past research has emphasized two critical economic concerns that appear to generate anti-immigrant sentiment among native citizens: concerns about labor market competition and concerns about the fiscal burden on public services. We provide direct tests of both models of attitude formation using an original survey experiment embedded in a nationwide U.S. survey. The labor market competition model predicts that natives will be most opposed to immigrants who have skill levels similar to their own. We find instead that both low-skilled and highly skilled natives strongly prefer highly skilled immigrants over low-skilled immigrants, and this preference is not decreasing in natives' skill levels. The fiscal burden model anticipates that rich natives oppose low-skilled immigration more than poor natives, and that this gap is larger in states with greater fiscal exposure (in terms of immigrant access to public services). We find instead that rich and poor natives are equally opposed to low-skilled immigration in general. In states with high fiscal exposure, poor (rich) natives are more (less) opposed to low-skilled immigration than they are elsewhere. This indicates that concerns among poor natives about constraints on welfare benefits as a result of immigration are more relevant than concerns among the rich about increased taxes. Overall the results suggest that economic self-interest, at least as currently theorized, does not explain voter attitudes toward immigration. The results are consistent with alternative arguments emphasizing noneconomic concerns associated with ethnocentrism or sociotropic considerations about how the local economy as a whole may be affected by immigration.
A ZERO-ONE RESULT FOR THE LEAST SQUARES ESTIMATOR

The least squares estimator for the linear regression model is shown to converge to the true parameter vector either with probability one or with probability zero. In the latter case, it either converges to a point not equal to the true parameter with probability one, or it diverges with probability one. These results are shown to hold under weak conditions on the dependent random variable and regressor variables. No additional conditions are placed on the errors. The dependent and regressor variables are assumed to be weakly dependent-in particular, to be strong mixing. The regressors may be fixed or random and must exhibit a certain degree of independent variability. No further assumptions are needed. The model considered allows the number of regressors to increase without bound as the sample size increases. The proof proceeds by extending Kolmogorov's 0-1 law for independent random variables to strong mixing random variables.
On Equivalence Relationships Between Classification and Ranking Algorithms

We demonstrate that there are machine learning algorithms that can achieve success for two separate tasks simultaneously, namely the tasks of classification and bipartite ranking. This means that advantages gained from solving one task can be carried over to the other task, such as the ability to obtain conditional density estimates, and an order-of-magnitude reduction in computational time for training the algorithm. It also means that some algorithms are robust to the choice of evaluation metric used; they can theoretically perform well when performance is measured either by a misclassification error or by a statistic of the ROC curve (such as the area under the curve). Specifically, we provide such an equivalence relationship between a generalization of Freund et al.'s RankBoost algorithm, called the "P-Norm Push," and a particular cost-sensitive classification algorithm that generalizes AdaBoost, which we call "P-Classification." We discuss and validate the potential benefits of this equivalence relationship, and perform controlled experiments to understand P-Classification's empirical performance. There is no established equivalence relationship for logistic regression and its ranking counterpart, so we introduce a logistic-regression-style algorithm that aims in between classification and ranking, and has promising experimental performance with respect to both tasks.
Touring Protein Space with Matt

Using the Matt structure alignment program, we take a tour of protein space, producing a hierarchical clustering scheme that divides protein structural domains into clusters based on geometric dissimilarity. While it was known that purely structural, geometric, distance-based measures of structural similarity, such as Dali/FSSP, could largely replicate hand-curated schemes such as SCOP at the family level, it was an open question as to whether any such scheme could approximate SCOP at the more distant superfamily and fold levels. We partially answer this question in the affirmative, by designing a clustering scheme based on Matt that approximately matches SCOP at the superfamily level, and demonstrates qualitative differences in performance between Matt and DaliLite. Implications for the debate over the organization of protein fold space are discussed. Based on our clustering of protein space, we introduce the Mattbench benchmark set, a new collection of structural alignments useful for testing sequence aligners on more distantly homologous proteins.
Geometrically Nonlinear Theory of Composite Beams with Deformable Cross Sections

dynamic equations that includes direct measures of both the large global displacement and rotations of a reference line, and the small local deformations of the cross sections. Two situations are studied in which this approach provides a simpler alternative to shell models with comparable fidelity. First, we look at the detailed structural response of composite beams with distributed loads. In particular, the case of a composite box beam with embedded piezoelectric actuators is considered. Second, this methodology is applied to study the low-frequency response characterization of composite beams. Numerical results in both cases show that a reduced set of finite-section modes allows a full description of the actual three-dimensional displacement field using a strictly one-dimensional formulation. Nomenclature A = area of the cross section ai = unit vectors of the reference coordinate system Bi = unit vectors of the local coordinate system in the deformed reference line bi = unit vectors of the local coordinate system in the undeformed reference line C sr = rotation tensor from coordinate systemsr tos c = tensor of material elastic constants ei = unit vector along thei-direction F = vector of cross-sectional internal forces fs0 = column matrix of applied conjugated forces ofq
Design of materials with extreme thermal expansion using a three-phase topology optimization method

Abstract Composites with extremal or unusual thermal expansion coefficients are designed using a three-phase topology optimization method. The composites are made of two different material phases and a void phase. The topology optimization method consists in finding the distribution of material phases that optimizes an objective function (e.g. thermoelastic properties) subject to certain constraints, such as elastic symmetry or volume fractions of the constituent phases, within a periodic base cell. The effective properties of the material structures are found using the numerical homogenization method based on a finite-element discretization of the base cell. The optimization problem is solved using sequential linear programming. To benchmark the design method we first consider two-phase designs. Our optimal two-phase microstructures are in fine agreement with rigorous bounds and the so-called Vigdergauz microstructures that realize the bounds. For three phases, the optimal microstructures are also compared with new rigorous bounds and again it is shown that the method yields designed materials with thermoelastic properties that are close to the bounds. The three-phase design method is illustrated by designing materials having maximum directional thermal expansion (thermal actuators), zero isotropic thermal expansion, and negative isotropic thermal expansion. It is shown that materials with effective negative thermal expansion coefficients can be obtained by mixing two phases with positive thermal expansion coefficients and void.
The dynamics of teacher quality

Abstract An extensive literature finds that while teachers vary considerably in initial quality there are limited teacher quality dynamics: except for the first few years of teaching, teacher quality does not improve over the course of a teacher's career. This study evaluates the importance of various modeling restrictions to the key findings of this literature. Using data covering all 5th grade public school teachers from the state of North Carolina, I replicate the findings of the previous literature using their restrictive experience assumptions. However, using an unrestricted experience model I find that for mathematics achievement there are high returns to later career teaching experience, about twice as much dispersion in initial teacher quality as previously estimated, and a pattern of negative selection where high quality teachers are more likely to exit.
Psychological and Physical Factors Involved in Chronic Idiopathic Prostatitis

Idiopathic prostatitis is a common, often chronic condition in which psychological factors are suspected to play a role. Men with chronic prostatitis (n = 51) and a control group of 34 men without any chronic pain condition, equivalent on demographic characteristics, were compared on psychological and perineal muscle tension measures. Prostate-specific antigen and expressed prostatic secretion cell counts were also measured. Chronic prostatitis patients were consistently more elevated than controls on hypochondriasis, depression, and hysteria (MMPI), and on somaticization and depression (Brief Symptom Inventory), and were less elevated on masculine/instrumentality (Personal Attributes Questionnaire) scales. A cluster analysis of MMPI profiles revealed that 57% of the chronic prostatitis patients produced generally unelevated MMPI profiles, whereas the remaining 43% fell into two groups with distinct patterns of distress. The results indicate depression and psychosocial distress are common among chronic prostatitis patients, calling for careful evaluation and attention to psychological symptoms.
Synthesis of cyclobutane lignans via an organic single electron oxidant–electron relay system

A direct method to synthesize lignan cyclobutanes and analogs via photoinduced electron transfer is presented. A variety of oxygenated alkenes are employed to furnish terminal or substituted cyclobutane adducts with complete regiocontrol, yielding cycloadducts with trans stereochemistry. Key to minimizing competing cycloreversion is the inclusion of an aromatic electron relay (ER). This method has been adapted to the synthesis of the natural products magnosalin and pellucidin A.
Inferring unusual crowd events from mobile phone call detail records

The pervasiveness and availability of mobile phone data offer the opportunity of discovering usable knowledge about crowd behavior in urban environments. Cities can leverage such knowledge to provide better services e.g., public transport planning, optimized resource allocation and safer environment. Call Detail Record CDR data represents a practical data source to detect and monitor unusual events considering the high level of mobile phone penetration, compared with GPS equipped and open devices. In this paper, we propose a methodology that is able to detect unusual events from CDR data, which typically has low accuracy in terms of space and time resolution. Moreover, we introduce a concept of unusual event that involves a large amount of people who expose an unusual mobility behavior. Our careful consideration of the issues that come from coarse-grained CDR data ultimately leads to a completely general framework that can detect unusual crowd events from CDR data effectively and efficiently. Through extensive experiments on real-world CDR data for a large city in Africa, we demonstrate that our method can detect unusual events with 16% higher recall and over 10$$\times $$ higher precision, compared to state-of-the-art methods. We implement a visual analytics prototype system to help end users analyze detected unusual crowd events to best suit different application scenarios. To the best of our knowledge, this is the first work on the detection of unusual events from CDR data with considerations of its temporal and spatial sparseness and distinction between user unusual activities and daily routines.
N-Heterocyclic Carbene-Initiated α-Acylvinyl Anion Reactivity: Additions of α-Hydroxypropargylsilanes to Aldehydes

Highly substituted α,β-unsaturated ketones are prepared by the N-heterocyclic carbene-initiated addition of α-hydroxypropargylsilanes to aldehydes. This strategy serves as a highly efficient alternative to the standard Morita−Baylis−Hillman (MBH) approaches for these types of compounds. In contrast to the MBH reaction, different substitution in the β-position of the product (R1) can be accommodated in moderate to excellent yields with a high degree of control over the resulting alkene.
The Individual, the Organization, and the Career: A Conceptual Scheme

This paper presents a set of concepts about the nature of the organization, the nature of the individual, and the nature of the career-the set of events which tie the individual and the organization together. The purpose is to provide a frame of reference and a set of concepts to make it possible to think in more empirical terms about a variable like "career," yet which relate this variable both to organizational and psychological variables. Concepts such as "organizational boundaries," labile and stable "social selves," career stages and transitional processes are used to generate some hypotheses about organizational influences on the individual (socialization) and individual influences on the organization (innovation).
Boronic acid compounds as potential pharmaceutical agents.

Boronic acid compounds have been used, because of their unique structural features, for the development of potent enzyme inhibitors, boron neutron capture agents for cancer therapy, and as antibody mimics that recognize biologically important saccharides. Consequently, there has been a surge of interests in boronic acid compounds. This study reviews the recent development in this area during the last six years.
Near-contact electrophoretic motion of a sphere parallel to a planar wall

The electrophoretic motion of a sphere resulting from an applied electric field directed parallel to a nearby plane wall is analysed for the case of a small sphere-wall gap width. The thin-Debye-layer approximation is employed. Using matched asymptotic expansions, the fluid domain is separated into an 'inner' (gap-scaled) region, wherein the electric field and velocity gradients are large, and an 'outer' (sphere-scaled) region, wherein field variations are moderate. Asymptotic expressions for the force and torque acting on the sphere are obtained using a reciprocal theorem, thereby avoiding the need to explicitly solve the pertinent Stokes equations. These expressions, as well as the sphere's electrophoretic mobility, become unbounded for near-contact separations. The present asymptotic solution complements existing 'exact' bipolar-coordinate eigenfunction expansions, which are numerically suitable only for O(1) gap thicknesses
Quest Hierarchy for Hyperspectral Face Recognition

A qualia exploitation of sensor technology (QUEST) motivated architecture using algorithm fusion and adaptive feedback loops for face recognition for hyperspectral imagery (HSI) is presented. QUEST seeks to develop a general purpose computational intelligence system that captures the beneficial engineering aspects of qualia-based solutions. Qualia-based approaches are constructed fromsubjective representations and have the ability to detect, distinguish, and characterize entities in the environment Adaptive feedback loops are implemented that enhance performance by reducing candidate subjects in the gallery and by injecting additional probe images during the matching process. The architecture presented provides a framework for exploring more advanced integration strategies beyond those presented. Algorithmic results and performance improvements are presented as spatial, spectral, and temporal effects are utilized; additionally, a Matlab-based graphical user interface (GUI) is developed to aid processing, track performance, and to display results.
LARGE SCALE STRUCTURE OF INTERFACES: AN INVERSE METHOD

We propose an inverse method to extract effective couplings and the renormalization group flow for growing interfaces. We apply it to discrete surface growth models in the Kardar-Parisi-Zhang universality class in 1+1 dimensions and obtain the first measurement of a universal coupling constant. We consider interfaces not in the steady state. It may also be applicable to analyze experimental data and for other forms of interface growth.
Total synthesis of the Isodon diterpene sculponeatin N.

The total synthesis of sculponeatin N, a bioactive polycyclic diterpene isolated from Isodon sculponeatus, is reported. Key features of the synthesis include diastereoselective Nazarov and ring-closing metathesis reactions, and a highly efficient formation of the bicyclo[3.2.1]octane ring system by a reductive radical cyclization.
Whole Field Measurement of Temperature in Water using Two-Color Laser Induced Fluorescence

A technique is described that measures the instantaneous three-dimensional temperature distribution in water using two-color laser-induced fluorescence (LIF). Two fluorescent dyes, Rhodamine B and Rhodamine 110, are used as temperature indicators. A laser light sheet scanned across the entire measurement volume excites the fluorescent dye, and an optical system involving a color beam splitter gives the intensity distribution of the individual fluorescent dyes on two separate monochrome CCD cameras. The ratio of these fluorescence intensities at each point of the image is calibrated against the temperature to eliminate the effect of the fluctuation of illuminating light intensity. A stable thermally stratified layer was measured by this system to evaluate the total accuracy of the measurement system. The random error of the measurement was ±1.4 K with 95% confidence. Measurements of thermal convection over a heated horizontal surface show temperature iso-surfaces having typical structures such as plumes, ridges and thermals.
Eddy current power dissipation at sharp corners

This paper develops corrections to the impedance per unit length when the conductor cross section includes sharp corners. The case of a right internal angle is treated in detail. Corrections are given for all real positive values of the ratio of internal to external magnetic permeabilities. Both the real and imaginary parts of the corrections are determined. Application of the results to a conductor of square cross section is given. Higher order terms are developed and compared to a numerical solution. These higher order terms are generalized to the conductor of rectangular cross section. >
A Vector Uniform Cramer-Rao Bound for SPECT System Design

In this paper, we present the use of modified uniform Cramer-Rao type bounds (MUCRB) for the design of single photon emission tomography (SPECT) systems. The MUCRB is the lowest attainable total variance using any estimator of an unknown vector parameter, whose mean gradient matrix satisfies a given constraint. Since the mean gradient is closely related to local impulse function, the MUCRB approach can be used to evaluate the fundamental tradeoffs between spatial resolution and variance that are achievable with a given SPECT system design. As a possible application, this approach allows one to compare different SPECT system designs based on the optimum average resolution-variance tradeoffs that can be achieved across multiple control-points inside a region-of-interest. The formulation of the MUCRB allows detailed modelling of physical aspects of practical SPECT systems and requests only a modest computation load. It can be used as an analytical performance index for comparing different SPECT system or aperture designs.
Comprehensive mutational scanning of a kinase in vivo reveals substrate-dependent fitness landscapes

Deep mutational scanning has emerged as a promising tool for mapping sequence-activity relationships in proteins, ribonucleic acid and deoxyribonucleic acid. In this approach, diverse variants of a sequence of interest are first ranked according to their activities in a relevant assay, and this ranking is then used to infer the shape of the fitness landscape around the wild-type sequence. Little is currently known, however, about the degree to which such fitness landscapes are dependent on the specific assay conditions from which they are inferred. To explore this issue, we performed comprehensive single-substitution mutational scanning of APH(3')II, a Tn5 transposon-derived kinase that confers resistance to aminoglycoside antibiotics, in Escherichia coli under selection with each of six structurally diverse antibiotics at a range of inhibitory concentrations. We found that the resulting local fitness landscapes showed significant dependence on both antibiotic structure and concentration, and that this dependence can be exploited to guide protein engineering. Specifically, we found that differential analysis of fitness landscapes allowed us to generate synthetic APH(3')II variants with orthogonal substrate specificities.
ANALYTICAL PARTITION OF SOFTWARE COMPONENTS FOR EVOLVABLE AND RELIABLE MEMS DESIGN TOOLS

Transforming software requirements into a software design involves the iterative partition of a solution into software components. The process is human-intensive and does not guarantee that design objectives such as reusability, evolvability, and reliable performance are satisfied. The costly process of designing, building, and modifying high-assurance systems motivates the need for precise methods and tools to generate designs whose corresponding implementations are reusable, evolvable, and reliable. This paper demonstrates an analytical approach for partitioning basic elements of a software solution into reusable and evolvable software components. First, we briefly overview the role of partitioning in current design methods and explain why computer-aided design (CAD) tools to automate the design of microelectromechanical systems (MEMS) are high-assurance applications. Then we present our approach and apply it to the design of CAD software to layout an optimized design of a MEMS accelerometer to be used in the navigational units of aircraft. Lastly, we discuss the implications of our approach and future research directions.
An experimental study of the small world problem

Arbitrarily selected individuals (N=296) in Nebraska and Boston are asked to generate acquaintance chains to a target person in Massachusetts, employing “the small world method” (Milgram, 1967). Sixty-four chains reach the target person. Within this group the mean number of intermediaries between starters and targets is 5.2. Boston starting chains reach the target person with fewer intermediaries than those starting in Nebraska; subpopulations in the Nebraska group do not differ among themselves. The funneling of chains through sociometric “stars” is noted, with 48 per cent of the chains passing through three persons before reaching the target. Applications of the method to studies of large scale social structure are discussed.
Growth and Ideas

Abstract Ideas are different from nearly all other economic goods in that they are nonrivalrous. This nonrivalry implies that production possibilities are likely to be characterized by increasing returns to scale, an insight that has profound implications for economic growth. The purpose of this chapter is to explore these implications.
Asymmetric Induction in Hydrogen-Mediated Reductive Aldol Additions to α-Amino Aldehydes Catalyzed by Rhodium: Selective Formation of syn-Stereotriads Directed by Intramolecular Hydrogen-Bonding

Rhodium-catalyzed hydrogenation of methyl vinyl ketone and ethyl vinyl ketone in the presence of N-Boc-alpha-aminoaldehydes 3a-8a at ambient temperature and pressure results in reductive C-C coupling to furnish aldol adducts 3b-8b and 3c-8c, respectively, which incorporate stereotriads that embody high levels of syn-aldol selectivity accompanied by high levels of anti-Felkin-Anh control. The collective data are consistent with a catalytic mechanism involving addition of the Z(O)-rhodium enolate to the sterically less-encumbered aldehyde pi-face of an intramolecularly hydrogen-bonded chelate through a Zimmerman-Traxler type transition structure. Stereochemical assignments are supported by single-crystal X-ray diffraction analysis of 5b-O-3,5-dinitrobenzoate, iso-5b, N-Me-iso-5b-O-3,5-dinitrobenzoate, and 7b. As revealed by HPLC analysis, optical purity of the stereochemically labile alpha-aminoaldehydes is completely preserved under the conditions of hydrogen-mediated aldol coupling. Deletion of the intramolecular hydrogen bond, as in the case of N-methyl-N-Boc-l-leucinal N-Me-5a, inverts stereoselectivity to furnish the Felkin-Anh product N-Me-iso-5b in 17% yield. Additionally, reactions performed in the presence of tert-amyl alcohol (10 equiv) exhibit markedly lower levels of anti-Felkin-Anh control (7:1 versus > or = 20:1). The collective studies suggest that intramolecular hydrogen bonding plays a key role in both activating the alpha-aminoaldehyde toward addition and directing facial selectivity.
Precision Astrometry With Adaptive Optics

We investigate the limits of ground-based astrometry with adaptive optics using the core of the Galactic globular cluster M5. Adaptive optics systems provide near diffraction-limit imaging with the world's largest telescopes. The substantial improvement in both resolution and signal-to-noise ratio enables high-precision astrometry from the ground. We describe the dominant systematic errors that typically limit ground-based differential astrometry, and enumerate observational considerations for mitigating their effects. After implementing these measures, we find that the dominant limitation on astrometric performance in this experiment is caused by tilt anisoplanatism. We then present an optimal estimation technique for measuring the position of one star relative to a grid of reference stars in the face of this correlated random noise source. Our methodology has the advantage of reducing the astrometric errors to and faster than the square root of the number of reference stars, effectively eliminating noise caused by atmospheric tilt to the point that astrometric performance is limited by centering accuracy. Using 50 reference stars, we demonstrate a single-epoch astrometric precision of ≈1 mas in 1 s, decreasing to 100 μas in 2 minutes of integration time at the Hale 200 inch telescope. We also show that our astrometry is accurate to 100 μas for observations separated by 2 months. Finally, we discuss the limits and potential of differential astrometry with current and next-generation large-aperture telescopes. At this level of accuracy, numerous astrometric applications become accessible, including planet detection, astrometric microlensing signatures, and kinematics of distant Galactic stellar populations.
Stereoselective construction and synthetic applications of phenylthio substituted iodoolefins

Abstract (E)- and (Z)-Phenylthio substituted iodoolefins 1 and 2 have been synthesized stereoselectively via lower order stannylcuprate addition to and hydroalumination of appropriate alkyne precursors. Their utility in model studies on the synthesis of calichemicin/esperamicin and neocarzinostatin aglycones is shown.
External Economies and International Trade Redux

We study a world with national external economies of scale at the industry level. In contrast to the standard treatment with perfect competition and two industries, we assume Bertrand competition in a continuum of industries. With Bertrand competition, each firm can internalize the externalities from production by setting a price below those set by others. This out-of-equilibrium threat eliminates many of the "pathologies" of the standard treatment. There typically exists a unique equilibrium with trade guided by "natural" comparative advantage. And, when a country has CES preferences and any finite elasticity of substitution between goods, gains from trade are ensured.
Ductal Patency in Neonates With Respiratory Distress Syndrome: A Randomized Surfactant Trial

• The purpose of this study was to evaluate in a controlled study the effect of exogenous surfactant on various manifestations of ductal patency. Premature infants with respiratory distress syndrome were randomized to receive surfactant (Survanta) (n=22) or air (n=14). In neonates receiving surfactant, there was a greater tendency for an audible murmur to develop (13 of 22 vs four of 14). In spite of this, the clinical use of indomethacin was similar for the two groups, 10 (45%) of 22 vs six (43%) of 14. Excluding neonates given indomethacin early, a comparable number of surfactant-treated neonates (9/17 [53%]) vs control neonates (6/12 [50%]) demonstrated spontaneous closure of the ductus within a physiologic time frame (on or before day 4). For the gestational ages studied, the beneficial effects of exogenous surfactant were not associated with either an increased risk for delayed closure of the ductus arteriosus or a greater incidence of indomethacin usage. Utilization of exogenous surfactant does not appear to have an adverse impact on ductal patency. ( AJDC . 1991;145:1017-1020)
The impact of regional trade agreements and trade facilitation in the Middle East and North Africa region

The Middle East and North Africa (MENA) region's trade performance over the past two decades has been disappointing. Efforts to boost trade through a plethora of regional trade agreements (RTAs) are underway. This study examines the potential contribution of regional trade agreements, as well as trade facilitation improvements, in enhancing the development prospects of the region. Using the Global Trade Analysis Project (GTAP) model and database, both intra-regional integration and integration with the European Union are observed to have a favorable impact on welfare in the MENA region. The welfare gains from integrating with the European Union are observed to be at least twice as much as intra-regional integration. Furthermore, these welfare gains are observed to at least triple when the implementation of the RTAs is complemented with trade facilitation improvements.
The Rohlin Property for Shifts of Finite Type

Abstract We show that an automorphism of a unital AF C * -algebra with a certain approximate Rohlin property has the Rohlin property. This generalizes a result of Kishimoto. Using this we show that the shift automorphism on the bilateral C * -algebra associated with an aperiodic irreducible shift of finite type has the Rohlin property.
The geometry of fusion inspired channel design

This paper is motivated by the problem of integrating multiple sources of measurements. We consider two multiple-input-multiple-output (MIMO) channels, a primary channel and a secondary channel, with dependent input signals. The primary channel carries the signal of interest, and the secondary channel carries a signal that shares a joint distribution with the primary signal. The problem of particular interest is designing the secondary channel matrix, when the primary channel matrix is fixed. We formulate the problem as an optimization problem, in which the optimal secondary channel matrix maximizes an information-based criterion. An analytical solution is provided in a special case. Two fast-to-compute algorithms, one extrinsic and the other intrinsic, are proposed to approximate the optimal solutions in general cases. In particular, the intrinsic algorithm exploits the geometry of the unit sphere, a manifold embedded in Euclidean space. The performances of the proposed algorithms are examined through a simulation study. A discussion of the choice of dimension for the secondary channel is given.
Continuous Locational Marginal Pricing (CLMP)

This paper proposes a solution to eliminate the step change in the curve of location marginal price (LMP) with respect to load variation. The new solution is named continuous locational marginal pricing (continuous LMP or CLMP) because it is a continuous function with respect to load. The present LMP methodology leads to a step change when a new constraint, either transmission or generation, becomes binding as load increases. Similarly, there is also a step change of LMP if an existing constraint is no longer binding when load decreases. The proposed CLMP methodology smoothes the step changes in the price curve and introduces a fourth component, future limit risk (FLR) price, in addition to the present three LMP components, energy price, congestion price, and loss price. also, FLR is an indication of how close the present system state moves to the next constraint. An algorithm is proposed in this paper to give a technically efficient method to calculate CLMP and FLR price. Two case studies are presented to demonstrate the proposed CLMP methodology.