cssi/SciSciGPT-SciSciNet huggingface dataset:
Better LATE Than Nothing: Some Comments on Deaton (2009) and Heckman and Urzua (2009)

Two recent papers, Deaton (2009), and Heckman and Urzua (2009), argue against what they see as an excessive and inappropriate use of experimental and quasi-experimental methods in empirical work in economics in the last decade. They specifically question the increased use of instrumental variables and natural experiments in labor economics, and of randomized experiments in development economics. In these comments I will make the case that this move towards shoring up the internal validity of estimates, and towards clarifying the description of the population these estimates are relevant for, has been important and beneficial in increasing the credibility of empirical work in economics. I also address some other concerns raised by the Deaton and Heckman-Urzua papers.
Relativistic mean-field theory and the high-density nuclear equation of state

Abstract The properties of high-density nuclear and neutron matter are studied using a relativistic mean-field approximation to the nuclear matter energy functional. Based on ideas of effective field theory, nonlinear interactions between the fields are introduced to parametrize the density dependence of the energy functional. Various types of nonlinearities involving scalar-isoscalar (σ), vector-isoscalar (ω) and vector-isovector (ϱ) fields are studied. After calibrating the model parameters at equilibrium nuclear matter density, the model and parameter dependence of the resulting equation of state is examined in the neutron-rich and high-density regime. It is possible to build different models that reproduce the same observed properties at normal nuclear densities, but which yield maximum neutron star masses that differ by more than one solar mass. Implications for the existence of kaon condensates or quark cores in neutron stars are discussed.
Uncertainty measures for general Type-2 fuzzy sets

Five uncertainty measures have previously been defined for interval Type-2 fuzzy sets (IT2 FSs), namely centroid, cardinality, fuzziness, variance and skewness. Based on a recently developed @a-plane representation for a general T2 FS, this paper generalizes these definitions to such T2 FSs and, more importantly, derives a unified strategy for computing all different uncertainty measures with low complexity. The uncertainty measures of T2 FSs with different shaped Footprints of Uncertainty and different kinds of secondary membership functions (MFs) are computed and are given as examples. Observations and summaries are made for these examples, and a Summary Interval Uncertainty Measure for a general T2 FS is proposed to simplify the interpretations. Comparative studies of uncertainty measures for Quasi-Type-2 (QT2), IT2 and T2 FSs are also performed to examine the feasibility of approximating T2 FSs using QT2 or even IT2 FSs.
A Lewis Acid Catalyzed annulation to 2,1-benzisoxazoles.

We report here a new, atom economical annulation to 2,1-benzisoxazole scaffolds via the BF3·Et2O-catalyzed reaction of glyoxylate esters and nitrosoarenes. The developed method represents a convergent route to this compound class from previously unexplored inputs and provides a range of 2,1-benzisoxazoles in moderate to high yields under convenient conditions. Along with exploration of substrate scope, initial mechanistic investigation through 18O labeling and the synthesis of a reaction intermediate provides evidence for an unusual umpolung addition of glyoxylates to nitrosobenzenes with high O-selectivity, followed by a new type of Friedel–Crafts cyclization.
Iridium−Monodentate Phosphoramidite-Catalyzed Asymmetric Hydrogenation of Substituted Benzophenone N−H Imines

Homogeneous asymmetric hydrogenation of unprotected benzophenone N-H imines 1a-r using Ir-(S)-N-benzyl-N-methyl-MonoPhos as a catalyst provides chiral amines 2a-r in 80-96% yield with enantioselectivities up to 98% ee (18 examples) for ortho-substituted substrates.
The viability of minority-owned banks

Abstract The poor performance of minority-owned banks that has been widely documented in the literature over the last three decades is not due to their operating environments. Even after local market conditions are considered, the findings of this study reveal that black and Hispanic banks generally underperform their nonminority peers competing in the same marketplace. High levels of government deposits in minority banks did not improve the long-term viability of these institutions. The one exception appears to be the Asian-American banks which are not found to be significantly different from their local nonminority peer banks.
Evaluating sliding and sticky target policies by measuring temporal drift in acyclic walks through a web archive

When viewing an archived page using the archive's user interface (UI), the user selects a datetime to view from a list. The archived web page, if available, is then displayed. From this display, the web archive UI attempts to simulate the web browsing experience by smoothly transitioning between archived pages. During this process, the target datetime changes with each link followed, potentially drifting away from the datetime originally selected. For sparsely archived resources, this almost transparent drift can be many years in just a few clicks. We conducted 200,000 acyclic walks of archived pages, following up to 50 links per walk, comparing the results of two target datetime policies. The Sliding Target policy allows the target datetime to change as it does in archive UIs such as the Internet Archive's Wayback Machine. The Sticky Target policy, represented by the Memento API, keeps the target datetime the same throughout the walk. We found that the Sliding Target policy drift increases with the number of walk steps, number of domains visited, and choice (number of links available). However, the Sticky Target policy controls temporal drift, holding it to $$<$$<30 days on average regardless of walk length or number of domains visited. The Sticky Target policy shows some increase as choice increases, but this may be caused by other factors. We conclude that based on walk length, the Sticky Target policy generally produces at least 30 days less drift than the Sliding Target policy.
A maximal affine stochastic volatility model of oil prices

This study develops and estimates a stochastic volatility model of commodity prices that nests many of the previous models in the literature. The model is an affine three-factor model with one state variable driving the volatility and is maximal among all such models that are also identifiable. The model leads to quasi-analytical formulas for futures and options prices. It allows for time-varying correlation structures between the spot price and convenience yield, the spot price and its volatility, and the volatility and convenience yield. It allows for expected mean-reversion in the short term and for an increasing expected long-term price, and for time-varying risk premia. Furthermore, the model allows for the situation in which options' prices depend on risk not fully spanned by futures prices. These properties are desirable and empirically important for modeling many commodities, especially crude oil. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 30:101–133, 2010
The norm of products of free random variables

Let Xi denote free identically-distributed random variables. This paper investigates how the norm of products \({\Pi_{n} = X_{1}X_{2}\cdots X_{n}}\) behaves as n approaches infinity. In addition, for positive Xi it studies the asymptotic behavior of the norm of \({Y_{n} = X_{1}\circ X_{2}\circ \cdots \circ X_{n},}\) where \({\circ}\) denotes the symmetric product of two positive operators: \({A\circ B=:A^{1/2}BA^{1/2}}\) . It is proved that if EXi = 1, then \({\left\Vert Y_{n}\right\Vert }\) is between \({c_{1}\sqrt{n}}\) and c2n for certain constant c1 and c2. For \({\left\Vert \Pi_{n}\right\Vert ,}\) it is proved that the limit of \({n^{-1}\log \left\Vert \Pi _{n}\right\Vert }\) exists and equals \({\log \sqrt{E\left( X_{i}^{\ast }X_{i}\right) }.}\) Finally, if π is a cyclic representation of the algebra generated by Xi, and if ξ is a cyclic vector, then \({n^{-1}\log \left\Vert \pi \left( \Pi _{n}\right) \xi \right\Vert = \log \sqrt{E\left( X_{i}^{\ast }X_{i}\right) }}\) for all n. These results are significantly different from analogous results for commuting random variables.
Expressing graph algorithms using generalized active messages

Recently, graph computation has emerged as an important class of high-performance computing application whose characteristics differ markedly from those of traditional, compute-bound, kernels. Libraries such as BLAS, LAPACK, and others have been successful in codifying best practices in numerical computing. The data-driven nature of graph applications necessitates a more complex application stack incorporating runtime optimization. In this paper, we present a method of phrasing graph algorithms as collections of asynchronous, concurrently executing, concise code fragments which may be invoked both locally and in remote address spaces. A runtime layer performs a number of dynamic optimizations, including message coalescing, message combining, and software routing. Practical implementations and performance results are provided for a number of representative algorithms.
A Structure Function Representation Theorem with Applications to Frequency Stability Estimation

Random processes with stationary nth differences serve as models for oscillator phase noise. The theorem proved here allows one to obtain the structure function (covariances of the nth differences) of such a process in terms of the differences of a single function of one time variable. In turn, this function can easily be obtained from the spectral density of the process. The theorem is used for computing the variance of two estimators of frequency stability.
Precautionary Reserves and the Interbank Market

Large excess reserve balances are held by banks in the U.S. despite the ability of large banks to closely target end-of-day balances close to zero. We show that the friction faced by small banks to participate in the fed funds market leads to all banks holding precautionary reserves. The precautionary motive for reserves can explain that small banks hold relatively large amounts of excess reserves overnight, while at the same time lending large amounts to large banks. Small banks are large net lenders despite their reluctance to lend as large of a percentage of available balances during the day as large banks. We also explain an increase in the volatility of the fed funds rate late in the day,
Exploring How Shroud Constraint Can Affect Vibratory Response in Turbomachinery

Unusual resonant responses were observed during spin pit tests of shrouded blades. The unusual behavior consisted of blades that exhibited strong response over a broad range of frequencies. The frequencies of peak resonance were considerably lower than predicted and were also lower than those observed in other tests of nominally identical wheels. In addition, the tracking plots of blade amplitudes versus frequency were truncated rather than displaying the usual sharp peaks seen in other tests. The unusual response is potentially dangerous since high vibratory response could be excited over a broad range of operating speeds. The blades were designed to be free standing with gaps of approximately 0.25 mm between neighboring shrouds. It is hypothesized that shroud contact at the blade tips could the unusual vibratory response. A simple model of a blade with shroud contact is developed in order to determine if shroud contact could cause blades to vibrate in the observed manner. The model is unusual in that it seeks to explore how contact could cause the blade to respond at lower (rather than higher) frequencies since contact typically increases the constraints on a structure and raises its natural frequencies
Fluorous-Assisted One-Pot Oligosaccharide Synthesis

A new method for oligosaccharide assembly that combines the advantages of one-pot synthesis and fluorous separation is described. After one-pot glycosylations are completed, a fluorous tag is introduced into the reaction mixture to selectively “catch” the desired oligosaccharide, which is rapidly separated from non-fluorous impurities by fluorous solid-phase extraction (F-SPE). Subsequent “release” of the fluo rous tag and F-SPE achieved the purification of the desired oligosaccharide without the use of time- and solvent-consuming silica gel chromatography. Linear and branched oligosaccharides have been synthesized with this approach in just a few hours (for the overall oligosaccharide assembly and purification process).
CEO Involvement in Director Selection: Implications for REIT Dividend Policy

This paper examines the relationship between CEO entrenchment and dividend policy of real estate investment trusts (REITs). We develop an index for CEO entrenchment using CEO tenure and duality and find that this index has significant impact on dividend policy. We further separate our sample into two sub-groups: REITs with and without nomination committees. Our analyses show a strong positive relationship between CEO entrenchment level and dividend payout for REITs without a nomination committee. In REITs with nomination committees, CEO entrenchment has less influence on dividend policy. We conclude that dividend policy serves as a substitution for other governance mechanisms. Further, our results are consistent with the evidence for other US firms—CEO that are more entrenched pay higher dividends to avoid shareholder sanctions and the threat of takeover.
Electrodynamics of disk-accreting magnetic neutron stars

We have investigated the electrodynamics of magnetic neutron stars accreting from Keplerian disks and the implications for particle acceleration and gamma-ray emission by such systems. We argue that the particle density in the magnetospheres of such stars is larger by orders of magnitude than the Goldreich-Julian density, so that the formation of vacuum gaps is unlikely. We show that even if the star rotates slowly, electromotive forces (EMFs) of order 10(exp 15) V are produced by the interaction of plasma in the accretion disk with the magnetic field of the neutron star. The resistance of the disk-magnetosphere-star circuit is small, and hence these EMFs drive very large conduction currents. Such large currents are likely to produce magnetospheric instabilities, such as relativistic double layers and reconnection events, that can accelerate electrons or ions to very high energies.
Tree and Loop Amplitudes in Open Twistor String Theory

We compute the one-loop gluon amplitude for the open twistor string model of Berkovits, using a symmetric form of the vertex operators. We discuss the classical solutions in various topologies and instanton sectors and the canonical quantization of the world sheet Lagrangian. We derive the N-point functions for the gluon tree and one-loop amplitudes, and calculate a general one-loop expression for the current algebra.
Using ionic liquid [EMIM][CH3COO] as an enzyme-‘friendly’ co-solvent for resolution of amino acids

Abstract An ionic liquid (IL), 1-ethyl-3-methylimidazolium acetate [EMIM][CH3COO], was used in 0–4.0 M (∼60% IL, v/v), as a nonvolatile organic medium for the enzymatic resolution of amino acids. When dl -phenylalanine methyl ester was studied as a model substrate, high enantiomeric excesses (ee) of l -amino acid were obtained in all ionic concentrations; however, lower yields were observed at high IL concentrations. This IL is more enzyme-‘friendly’ than the hydrophilic organic solvent acetonitrile and those ILs containing chaotropic anions (such as [EMIM][OTs]). Among three proteases and two lipases investigated, lyophilized Bacillus licheniformis protease exhibited the best enantioselectivity and activity. Highly enantioselective resolutions were also produced for several other amino acids in 2.0 M IL. Interestingly, high ee were also found in deuterium oxide (D2O) rather than in ordinary water, and a further enhancement was achieved with the co-existence of [EMIM][CH3COO]. The heavy water effect was explained in terms of protein stabilization by D2O. The secondary structural changes of enzyme in various media were interpreted by the second derivatives of FT-IR spectra.
Readily Accessible and Easily Modifiable Ru-Based Catalysts for Efficient and Z-Selective Ring-Opening Metathesis Polymerization and Ring-Opening/Cross-Metathesis

Rationally designed Ru-based catalysts for efficient Z-selective olefin metathesis are featured. The new complexes contain a dithiolate ligand and can be accessed in a single step from commercially available precursors in 68–82% yield. High efficiency and exceptional Z selectivity (93:7 to >98:2 Z:E) were achieved in ring-opening metathesis polymerization (ROMP) and ring-opening/cross-metathesis (ROCM) processes; the transformations typically proceed at 22 °C and are operationally simple to perform. Complete conversion was observed with catalyst loadings as low as 0.002 mol %, and turnover numbers of up to 43 000 were achieved without rigorous substrate purification or deoxygenation protocols. X-ray data and density functional theory computations provide support for key design features and shed light on mechanistic attributes.
Dynamical SUSY Breaking with a Hybrid Messenger Sector

Abstract In this paper we present a dynamical model of SUSY breaking with a hybrid messenger sector. SUSY is broken dynamically at a scale of order 10 9 GeV via strong SU(2) gauge interactions. SUSY breaking is then transmitted to the observable sector via two distinct sources: (1) messengers, carrying Standard Model gauge quantum numbers, with the messenger mass of order 10 15 GeV, and (2) the D term of an anomalous U(1) X . The model is quite constrained. The messenger scale is fixed by the Fayet-Iliopoulos term for the anomalous U(1) X interaction. In addition, we show that the D term SUSY breaking contributions to squark and slepton masses are “naturally” the same order as those coming from the messengers.
Decomposing Racial and Ethnic Differences in Small Business Lending: Evidence of Discrimination

In this paper, we use the Blinder–Oaxaca method for nonlinear models to decompose observed differences in credit rationing of small businesses between white- and minority-owned firms in the USA. We utilize a representative dataset of small businesses from the Survey of Small Business Finances between 1987 and 2003. Our results show that minority owners, on average, have about a 24 percentage points higher loan denial rate than white-owned firms and about three quarters of the difference is attributed to discrimination in bank lending. Although the difference in the probability of getting a smaller loan than requested is only 5 percentage points, this difference is almost entirely attributed to discrimination.
An experimental study of space chamber molecular kinetics.

Increased simulation of the near perfect molecular sink found in space is desirable for present and future space chambers. However, the parameter pressure as conventionally defined is an inadequate means of expressing simulation fidelity in such chambers. An experiment was conducted to illustrate the importance of molecular flux upon simulation fidelity and to show the effects of various gases and chamber geometries upon the chamber molecular flux profiles. The experimental results were compared to a theoretical flux profile calculation. Good agreement was obtained in the definition of molecular fluxes upon a centrally suspended vehicle; differences between theory and experiment were observed in the flux profiles near a solar simulator in the chamber wall. The conclusions reached from the study were integrated with previous work in space chamber molecular kinetics.
Theory of ion acceleration with closed electron drift

A theory is developed for Ex H acceleration of ions in channels with closed electron drift paths. Two classes of solutions were found depending on whether the electron temperature was constant throughout the acceleration channel or allowed to rise as the anode was approached. In the case of constant electron temperature a continuous potential variation was obtained. This solution corresponds, from the experimental viewpoint, to the Hall-current accelerator. If the electron temperature was allowed to rise, a near discontinuous jump was predicted at the positive end of the acceleration channel. This solution corresponds to the anode-layer accelerator described in Soviet literature.
E2 Strength in the Radiative Charmed Baryon Decay

Abstract The radiative decay ∑ Q ∗ → Λ Qγ can have both magnetic dipole (M1) and electric quadrupole (E2) components. In the heavy quark limit M Q → ∞ the transition arises from the spin of the light degrees of freedom changing from s l = 1 to s l = 0 and hence the E2 contribution vanishes. We compute the leading contribution to the E2 strength in chiral perturbation theory and find that the amplitude is enhanced by a small energy denominator in the chiral limit. This enhancement essentially compensates for the 1 M c suppression that is present in the charm system. We find a mixing ratio of order a few percent dependent upon the ∑ c -∑ c ∗ spin symmetry breaking mass difference. The analogous quantity in the b-baryon sector is smaller by a factor of ∼ M c M b .
SELECTIVELY MATERIALIZING DATA IN MEDIATORS BY ANALYZING USER QUERIES

There is currently great interest in building information mediators that can integrate information from multiple data sources such as databases or Web sources. The query response time for such mediators is typically quite high, mainly due to the time spent in retrieving data from remote sources. We present an approach for optimizing the performance of information mediators by selectively materializing data. We first present our overall framework for materialization in a mediator environment. The data is materialized selectively. We outline the factors that are considered in selecting data to materialize. We present an algorithm for identifying classes of data to materialize by analyzing one of the factors which is the distribution of user queries. We present results with an implemented version of our optimization system for the Ariadne information mediator, which show the effectiveness of our algorithm in extracting patterns of frequently accessed classes from user queries. We also demonstrate the effectiveness of approach in optimizing mediator performance by materializing such classes.
Picosecond all-optical switching in hydrogenated amorphous silicon microring resonators

We utilize cross-phase modulation to observe all-optical switching in microring resonators fabricated with hydrogenated amorphous silicon (a-Si:H). Using 2.7-ps pulses from a mode-locked fiber laser in the telecom C-band, we observe optical switching of a cw telecom-band probe with full-width at half-maximum switching times of 14.8 ps, using approximately 720 fJ of energy deposited in the microring. In comparison with telecom-band optical switching in undoped crystalline silicon microrings, a-Si:H exhibits substantially higher switching speeds due to reduced impact of free-carrier processes.
The skewness of the aperture mass statistic

We present simple formulae for calculating the skewness and kurtosis of the aperture mass statistic for weak lensing surveys, which is insensitive to masking effects of survey geometry or variable survey depth. The calculations are the higher order analogues of the formula given by Schneider, van Waerbeke & Mellier, which has been used to compute the variance of the aperture mass from several lensing surveys. As our formula requires the three-point shear correlation function, we also present an efficient tree-based algorithm for measuring it. We show how our algorithm would scale in computing time and memory usage for future lensing surveys. We also apply the procedure to our Cerro Tololo Inter-American Observatory (CTIO) survey data, originally described by Jarvis et al. We find that the skewness is positive (inconsistent with zero) at the 2a level. However, the signal is too noisy from this data to usefully constrain cosmology.
Critical theories of the dissipative Hofstadter model

Abstract It has recently been shown that the dissipative Hofstadter model (dissipative quantum mechanics of an electron subject to uniform magnetic field and periodic potential in two dimensions) exhibits critical behavior on a network of lines in the dissipation/magnetic field plane. Apart from their obvious condensed matter interest, the corresponding critical theories represent non-trivial solutions of open string field theory, and a detailed account of their properties would be interesting from several points of view. A subject of particular interest is the dependence of physical quantities on the magnetic field since it, much like θ QCD , serves only to give relative phases to different sectors of the partition sum. In this paper we report the results of an initial investigation of the free energy, N -point functions and boundary state of this type of critical theory. Although our primary goal is the study of the magnetic field dependence of these quantities, we will present some new results which bear on the zero magnetic field case as well.
Priming Effects With Drugs and Other Reinforcers

Abstinent drug users often report that taking even a small amount of their previously abused drug increases their desire for the drug and can lead to a full relapse. This apparent "priming" effect of drugs has been studied in both laboratory animals and humans. In animals trained to selfadminister drugs, small amounts of a previously self-administered drug readily reinstate responding. In humans, administration of a previously abused drug increases self-reported craving and desire for the drug. Priming effects also occur with other reinforcers (e.g., presentation of a food stimulus increases food-reinforced responding). This article examines the generality of priming phenomena, and it examines some of the learned or unlearned processes that underlie the effect. Abstinent drug users who consume even a small quantity of their previously preferred drug often report that the drug increases both the subjective desire for more of the drug and the likelihood of resuming regular use of the drug. One of the basic tenets of Alcoholics Anonymous is that a single alcoholic drink greatly increases the risk that an abstinent individual will relapse, or return to regular, excessive alcohol use (Alcoholics Anonymous, 1955). This effect is thought to occur even after long periods of abstinence and is even believed to extend to the alcoholic individual's responses to other classes of psychoactive drugs, such as tranquilizers and sedatives. Similarly, many cigarette smokers report that they failed in previous attempts to quit when they "tested themselves," or sampled, even one or two puffs from a cigarette. Even ex-smokers who successfully abstain from smoking for lengthy periods of time report that having a single cigarette markedly increases their desire to smoke and their likelihood of relapsing. This apparent increase in the motivation to consume a drug after a single dose of the drug is referred to as the priming effect. Priming is likely to be an important factor in relapse to drug abuse. Whereas many drug users succeed in achieving an initial period of abstinence, most of these users relapse within a relatively short period of time. The relapse process is likely to consist of several phases, including, for example, an initial phase that results in the first re-use of the drug, and a secondary phase that begins' as soon as the drug is ingested. Shiffman (1986) has studied the factors involved in the initial phase using retrospective reports from relapsed drug users. Drug users reported that relapse episodes may be precipitated by a wide range of situations and stimuli, including positive and negative emotional states and intra- and interpersonal factors. During the second phase (i.e., after the drug is ingested), other factors may prevail. For example, the direct pharmacological effects of the drug or learned associations resulting from previous administrations of the drug may influence behavior.
Competition policy trends and economic growth: Cross-national empirical evidence

Abstract Motivated by the general lack of empirical scholarship concerning the cross‐national environment for competition policy, I present measures here of the overall resources dedicated to competition policy and the merger policy work‐load for thirty‐two antitrust jurisdictions over the 1992–2007 period. The data allow a number of perceived trends in competition policy over the last two decades to be analysed, and allow the generation of some factual insights concerning these trends: e.g. the budgetary commitment to competition policy in the cross‐national environment for antitrust has substantially increased over this period; budgetary increases appear to be commensurate with increased antitrust workloads, and yet, the role of economics does not appear to have substantially increased relative to the role of law. Moreover, I am also able to provide some evidence that budgetary commitments to antitrust institutions yield economic benefits in terms of improved economic growth: i.e. higher budgetary commi...
Deconstructing noncommutativity with a giant fuzzy moose

We argue that the worldvolume theories of D-branes probing orbifolds with discrete torsion develop, in the large quiver limit, new non-commutative directions. This provides an explicit `deconstruction' of a wide class of noncommutative theories. This also provides insight into the physical meaning of discrete torsion and its relation to the T-dual B field. We demonstrate that the strict large quiver limit reproduces the matrix theory construction of higher-dimensional D-branes, and argue that finite `fuzzy moose' theories provide novel regularizations of non-commutative theories and explicit string theory realizations of gauge theories on fuzzy tori. We also comment briefly on the relation to NCOS, (2,0) and little string theories.
Preparation and Wittig reactions of an α-keto amino acid derivative

Le benzhydrylideneamide t-butyle ester de l'acide oxalique a ete synthetise, par reaction de Wittig il conduit a des esters N-benzhydrylidene de deshydroaminoacides
Palladium-Catalyzed β-Allylation of 2,3-Disubstituted Indoles

Given the prevalence of the indole nucleus in biologically active compounds, the direct C3-functionalization of 2,3-disubstituted indoles represents an important problem. Described is a general, high-yielding method for the palladium-catalyzed β-allylation of carba- and heterocycle fused indoles, including complex natural product substrates.
The effect of discrimination training on speech perception: Noncategorical perception

Three subjects were given extensive practice in discriminating syllables which differed in voice onset time. For these subjects, there were two major findings. First, discrimination of speech follows normal psychophysical laws: long-onset-time stimuli require larger differences than shorter ones for comparable discrimination. Second, the shape of the discrimination function for experienced subjects is more like a leaning W than an inverted V, the usual shape for naive subjects. The data support a model of speech perception with both an acoustic and a phonetic component. The phonetic component is best characterized as a prototype matching process, with the prototype including information on the simultaneity of formant onset.
Minimization of the Peak-to-Peak Gain in Periodic Systems Under Full State Feedback

Abstract The paper considers the minimization of the l∞-induced norm of the closed loop in linear periodically time varying (LPTV) systems when state information is available for feedback. A state-space approach is taken and concepts of viability theory and controlled invariance are utilized. It is shown that a memoryless periodically varying nonlinear controller can be constructed to achieve near-optimal performance. The construction involves the solution of several finite linear programs and generalizes to the periodic case earlier work on linear time-invariant systems (LTI).
The liquid crystal light valve, an optical-to-optical interface device☆

Abstract A new device is described that transfers high resolution, two-state (black and white) images from a noncoherent beam of light to a fully coherent beam of light in quasi real-time (less than 1 sec). The device is a photoconductor activated liquid crystal light valve that operates in the dynamic scattering mode of the liquid crystal. It has sensitivity of 1–10 μW/cm 2 (at 5100 A), resolution of 100 lines/mm and cycles on and off in 0.25 sec or less. This paper describes the construction and operation of the device and discusses its application to coherent optical data processing.
Control design variable linking for optimization of structural/control systems

A method is presented to integrate the design space of structural/control system optimization problems in the case of linear state feedback control. Conventional structural sizing variables and elements of the feedback gain matrix are both treated as strictly independent design variables in optimization by extending design variable linking concepts to the control gains. Several approximation concepts including new control design variable linking schemes are used to formulate the integrated structural/control optimization problem as a sequence of explicit nonlinear mathematical programming problems. Examples which involve a variety of behavior constraints, including constraints on dynamic stability, damped frequencies, control effort, peak transient displacement, acceleration, and control force limits, are effectively solved by using the method presented.
Chiral metal as a ferromagnetic super spin chain

Abstract The electrons on the surface of a disordered multi-layer integer quantum Hall system constitute an unusual chiral metal with ballistic motion transverse to the field, and diffusive motion parallel to it. We present a non-perturbative analytic treatment of an appropriate model, consisting of disordered chiral fermions in two dimensions. A supersymmetric generating functional is set up for the correlation functions of this system. The strong disorder limit is mapped into a supersymmetric spin chain, with ferromagnetic exchange coupling, reflecting the electron's chiral motion. The ferromagnetic ground state and the spin wave excitations, corresponding to the diffusion modes of the chiral metal, are found exactly. The parametric density of states correlator in the ergodic limit is computed from a Boltzmann-weighted sum over low-energy spin states. The result is of a universal form and coincides with that for a hermitian random matrix.
Storm Morphology and Rainfall Characteristics of TRMM Precipitation Features

Abstract Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), TRMM Microwave Imager (TMI), and Visible and Infrared Scanner (VIRS) observations within the Precipitation Feature (PF) database have been analyzed to examine regional variability in rain area and maximum horizontal extent of rainfall features, and role of storm morphology on rainfall production (and thus modes where vertically integrated heating occurs). Particular attention is focused on the sampling geometry of the PR and the resulting impact on PF statistics across the global Tropics. It was found that 9% of rain features extend to the edge of the PR swath, with edge features contributing 42% of total rainfall. However, the area (maximum dimension) distribution of PR features is similar to the wider-swath TMI up until a truncation point of nearly 30 000 km2 (250 km), so a large portion of the feature size spectrum may be examined using the PR as with past ground-based studies. This study finds distinct differences in land an...
Compact roundtrip routing with topology-independent node names

Consider a strongly connected directed weighted network with n nodes. This paper presents compact roundtrip routing schemes with [email protected]?(n) sized local tables and stretch 6 for any strongly connected directed network with arbitrary edge weights. A scheme with local tables of size [email protected]?(@e^-^1n^2^/^k) and stretch min((2^k^/^2-1)([email protected]),8k^2+4k-4), for any @e>0 is also presented in the case where edge weights are restricted to be polynomially-sized. Both results are for the topology-independent node-name model. These are the first topology-independent results that apply to routing in directed networks.
Linear parametric instabilities at high-pump powers

The linear parametric decay and oscillating two‐stream instabilities have been studied at high‐pump power for perturbations propagating oblique to the pump field. The electrostatic Vlasov–Poisson system for a homogeneous two‐component plasma has been solved numerically to investigate the high‐frequency branches of these instabilities. Results show that the maximum growth rate of the oscillating two‐stream instability occurs oblique to the pump field for power levels above a critical value. The angular dependence of this growth rate is dependent on the electron‐ion mass ratio. For these cases, the maximum value of the oscillating two‐stream growth rate remains constant for increasing power above the critical level while the direction of maximum growth rate becomes more oblique to the pump field and the volume in k space of the unstable region increases. The maximum value of the parametric decay growth rate increases with increasing power level and occurs parallel to the pump field for all values of pump intensity investigated.
A signalizer functor theorem for groups of finite Morley rank

There is a longstanding conjecture, due to Gregory Cherlin and Boris Zilber, that all simple groups of finite Morley rank are simple algebraic groups. Towards this end, the development of the theory of groups of finite Morley rank has achieved a good theory of Sylow 2-subgroups. It is now common practice to divide the Cherlin–Zilber conjecture into different cases depending on the nature of the connected component of the Sylow 2-subgroup, known as the Sylow◦ 2-subgroup. We shall be working with groups whose Sylow◦ 2-subgroup is divisible, or odd type groups. To date, the main theorem in the area of odd type groups is Borovik’s trichotomy theorem. The “trichotomy” here is a case division of the minimal counterexamples within odd type. More technically, Borovik’s result represents a major success at transferring signalizer functors and their applications from finite group theory to the finite Morley rank setting. The major difference between the two settings is the absence of a solvable signalizer functor theorem. This forced Borovik to work only with nilpotent signalizer functors, and the trichotomy theorem ends up depending on the assumption of tameness to assure that the necessary signalizer functors are nilpotent. The present paper shows that one may obtain a connected nilpotent signalizer functor from any sufficiently non-trivial solvable signalizer functor. This result plugs seamlessly into Borovik’s work to eliminate the assumption of tameness from his trichotomy theorem. In the meantime, a new approach to the trichotomy theorem has been developed by Borovik [7], based on the “generic identification theorem” of Berkman and Borovik [5]. Borovik uses his original signalizer functor arguments, and incorporates the result of the present paper. The paper is organized as follows. The first section will develop a limited characteristic zero notion of unipotence to complement the usual p-unipotence theory. The section on centralizers and generation which follows will establish some background needed in the rest of the paper. In Section 4 we prove our main result on signalizer functors, and in Section 5 we discuss some applications. With Borovik’s kind permission, we include a proof of the nilpotent signalizer functor theorem as an appendix. The results of Section 3 are based in part on a section of an unpublished version of [3].
EXPERTS AND THEIR RECORDS

A market where short-lived customers interact with long-lived experts is considered. Experts privately observe which treatment best serves a customer, but are free to choose more or less profitable treatments. Customers only observe records of experts' past actions. If experts are homogeneous there exists an equilibrium where experts always choose the customer's preferred treatment (play truthfully). Experts are incentivized with the promise of future business: new customers tend to choose experts who performed less profitable treatments in the past. If expert payoffs are private information, experts can never always be truthful. But sufficiently patient experts may be truthful almost always. (JEL C73, D82)
Abstracting abstract machines: a systematic approach to higher-order program analysis

Predictive models are fundamental to engineering reliable software systems. However, designing conservative, computable approximations for the behavior of programs (static analyses) remains a difficult and error-prone process for modern high-level programming languages. What analysis designers need is a principled method for navigating the gap between semantics and analytic models: analysis designers need a method that tames the interaction of complex languages features such as higher-order functions, recursion, exceptions, continuations, objects and dynamic allocation. We contribute a systematic approach to program analysis that yields novel and transparently sound static analyses. Our approach relies on existing derivational techniques to transform high-level language semantics into low-level deterministic state-transition systems (with potentially infinite state spaces). We then perform a series of simple machine refactorings to obtain a sound, computable approximation, which takes the form of a non-deterministic state-transition systems with finite state spaces. The approach scales up uniformly to enable program analysis of realistic language features, including higher-order functions, tail calls, conditionals, side effects, exceptions, first-class continuations, and even garbage collection.
New variable-population paradoxes for resource allocation

We identify previously unnoticed ways in which agents can strategically distort allocation rules, by affecting the set of “active” agents. (i) An agent withdraws with his endowment. (ii) He gives control of his endowment to someone else and withdraws. (iii) He invites someone in and let him use some of his endowment. (iv) He pre-delivers to some other agent the net trade that the rule would assign to that second agent if that second agent had participated. In (i) and (ii), he and his co-conspirator may end up controlling resources that allow them to reach higher welfare levels than they otherwise would. In (iii) and (iv), he may end up with a bundle that he prefers to the one he would have been assigned had he not engaged in the manipulation. We show that (i) the Walrasian rule is not “withdrawing-proof”, nor “endowments-merging-proof, nor “endowments-splitting-proof”, but that it is “pre-delivery-proof”, and that (ii) canonical selections from the egalitarian-equivalence-in-trades solutions satisfy none of the properties.
Considerations concerning the radiative corrections to muon decay in the Fermi and Standard theories

The FAC, PMS, and BLM optimization methods are applied to the QED corrections to the muon lifetime in the Fermi V-A theory. The FAC and PMS scales are close to me, while the BLM scale nearly coincides with the geometric average √memμ. The optimized expressions are employed to estimate the third order coefficient in the α(mμ) expansion and the theoretical error of the perturbative series. Using arguments based on effective field theory and a simple examination of Feynman diagrams, it is shown that, if contributions of O(αmμ2/MW2) are neglected, the corrections to muon decay in the SM factorize into the QED correction of the Fermi V-A theory and the electroweak amplitude g2/(1 − Δr), both of which are strictly scale-independent. We use the results to clarify how the QED corrections to muon decay and the Fermi constant GF should be used in the SM, and what is the natural choice of scales if running couplings are employed.
The age of globular clusters

Abstract I review here recent developments which have affected our understanding of both the absolute age of globular clusters and the uncertainties in this age estimate, and comment on the implications for cosmological models. This present estimate is in agreement with the range long advocated by David Schramm. The major uncertainty in determining ages of globular clusers based upon the absolute magnitude of the main sequence turn-off remains the uncertainty in the distance to these clusters. Estimates of these distances have recently been upwardly revised due to Hipparcos parallax measurements, if one calibrates luminosities of main sequence stars. However, it is important to realize that at the present time, different distance measures are in disagreement. A recent estimate is that the oldest clusters are 11.5±1.3 Gyr, implying a one-sided 95% confidence level lower limit of 9.5 Gyr, if statistical parallax distance measures are not incorporated. Incorporating more recent measures, including Hipparcos-based statistical parallax measures, raises the mean predicted age to 12.8±1 Gyr, with a 95% confidence range of 10–17 Gyr. I conclude by discussing possible improvements which may allow a more precise age distribution in the near future.
Resolution of nucleic acids by high-performance liquid chromatography

Abstract High-performance liquid chromatography is a very powerful technique for the separation and isolation of nucleic acids. Nucleic acids can be generally characterized as long, negatively charged polymers with hydrophobic nucleobases. Chromatographic processes which use electrostatic interactions (anion-exchange), hydrophobic interactions (reversed-phase or salting-out) or both types of interactions (mixed-mode) are most effective for resolution of these materials.
Reductive Amination with Zinc Borohydride. Efficient, Safe Route to Fluorinated Benzylamines

Abstract Abstract: Fluorinated benzylamines are synthesized in high yields by reductive alkylation of secondary amines with appropriate fluoroaldehydes using a combination of zinc chloride and zinc borohydride. The present method offers an alternative to toxic sodium cyanoborohydride and is adaptable to multigram-scale preparations.
Lateral velocity variation related correction in asymptotic true-amplitude one-way propagators

It was mathematically proved that the asymptotic true-amplitude one-way wave equation could provide the same amplitude as the full-wave equation in heterogeneous lossless media in the sense of high-frequency asymptotics. Much work has been done on the vertical velocity variation related amplitude correction term but the lateral velocity variation related term has not received much attention, even being excluded in some asymptotic true-amplitude one-way propagator formulations. Here we analyse the effects of different amplitude correction terms in the asymptotic true-amplitude one-way propagator, especially the effect related to the lateral velocity variation, by comparing the wavefield amplitude from the one-way propagator with that from full-wave modelling. We derive a dual-domain wide-angle screen type asymptotic true-amplitude one-way propagator and evaluate two implementations of the amplitude correction. Numerical examples show that the lateral velocity variation related correction term can play a significant role in the asymptotic true-amplitude one-way propagator. Optimization of the expansion coefficients in the asymptotic true-amplitude one-way propagator can improve both the amplitude and phase accuracy for wide-angle waves.