cssi/SciSciGPT-SciSciNet huggingface dataset:
The character sheaves on the group compactification

Abstract We give a definition of character sheaves on the group compactification which is equivalent to Lusztig's definition in [G. Lusztig, Parabolic character sheaves, II, Mosc. Math. J. 4 (4) (2004) 869–896]. We also prove some properties of the character sheaves on the group compactification.
Narrative and VAR approaches to monetary policy: Common identification problems

Abstract Romer and Romer [Romer, C.D., Romer, D.H. 1989. Does monetary policy matter? A new test in the spirit of Friedman and Schwartz. In: Blanchard, O.J., Fischer, S. (Eds.), NBER Macroeconomics Annual 1989. MIT Press, Cambridge, MA, pp. 121–170; Romer, C.D., Romer, D.H., 1994. Monetary policy matters. Journal of Monetary Economics 34, 75–88] adopted a narrative approach to address the identification problems in time series models of monetary policy. Based on Federal Reserve documents, the Romers created a dummy variable equal to one in periods when the Federal Reserve contracted in response to perceived inflationary pressures. This paper shows: (1) the dummy variable is predictable from past macroeconomic variables, reflecting the endogenous response of policy to the economy; (2) unpredictable changes in the dummy do not generate dynamic responses that look like the effects of monetary policy. The identification problems that plague time series models also afflict the narrative approach.
Balance of Payments and Related Issues in the Uruguay Round of Trade Negotiations

Little attention has been paid to the balance of payments provisions of the General Agreement on Tariffs & Trade (GATT), despite the fact that they directly influence the trade policies of the developing countries. This article suggests that there is a need to reconsider these provisions in the context of the ongoing Uruguay Round of multilateral trade negotiations. The article traces the historical evolution of GATT practices on trade restrictions for balance of payments purposes. With the general introduction of more flexible exchange rate arrangements, the original rationale for temporary barriers to safeguard a country's external financial position appears to have lost its force. Recent theoretical and empirical work has demonstrated that neutral or export promoting trade strategies are more effective for development than the import substitution frequently advocated by economists in the 1950s and 1960s. The current debt problems of developing countries strengthen the argument for a relatively open trade and payments regime to attain balance of payments viability. The article suggests that stronger international discipline over trade restrictions for balance of payments purposes would contribute to and presuppose other necessary improvements in the multilateral trading system which are already on the agenda of the Uruguay Round.
Short lists for shortest descriptions in short time

Is it possible to find a shortest description for a binary string? The well-known answer is "no, Kolmogorov complexity is not computable." Faced with this barrier, one might instead seek a short list of candidates which includes a laconic description. Remarkably such approximations exist. This paper presents an efficient algorithm which generates a polynomial-size list containing an optimal description for a given input string. Along the way, we employ expander graphs and randomness dispersers to obtain an Explicit Online Matching Theorem for bipartite graphs and a refinement of Muchnik's Conditional Complexity Theorem. Our main result extends recent work by Bauwens, Mahklin, Vereshchagin, and Zimand.
Bending and stretching of elastically coupled circular plates on elastic foundation

Abstract The general problem of the bending and stretching of two elastically coupled circular plates on elastic foundation subjected to axisymmetric thermal and static loadings is defined and solved exactly. Coupling between in-plane and out-of-plane deformation is considered as well as the arbitrary location of the points of fixity of the coupling elements with respect to the plate middle surfaces. Stiffness matrices of the coupling and the foundation elements introduced in the definition of the strain energy allow any desired degree of sophistication when evaluating the compliance of these elements. The general decoupled solution, together with a number of special cases of practical importance, is also given. The equations for the computer programming of the general solution are included. The solution is well suited for the analysis of core support plates of nuclear reactor pressure vessels as well as to the closely spaced double tube sheet heat exchangers of nuclear submarines.
Gunning for efficiency with third party enforcement in threshold public goods

When public goods can only be provided when donations cross a minimum threshold, this creates an advantage in that Pareto Efficient outcomes can be Nash Equilibria. Despite this, experiments have shown that groups struggle to coordinate on one of the many efficient equilibria. We apply a mechanism used successfully in continuous public goods games, the Hired Gun Mechanism (Andreoni and Gee in J. Public Econ. 96(11–12):1036–1046, 2012), to see if it can successfully get subjects across the threshold. When we use the mechanism to eliminate only inefficient equilibria, without addressing coordination, there is a modest but statistically insignificant improvement with the mechanism. However, when we hone the mechanism to eliminate all but one of the provision-point equilibria, thereby addressing the coordination issue, the mechanism moves all subjects to the desired efficient outcome almost immediately. In fact, after only one round using the hired gun mechanism, all subject are coordinating on the chosen equilibrium. The mechanism can be applied in settings where a group (1) has a plan for public good provision, (2) can measure contributions, (3) can fine members and (4) has an agreed upon standard for expected contributions. In these settings simple punishments, when focused on solving coordination as well as free riding, can greatly improve efficiency.
An Examination of the 1992 Increase in the Allowable Carryover of Reserves in the Bank Settlement Process

This paper examines the Federal Reserve's increase of the allowable carryover in the bank settlement process to improve bank flexibility in achieving settlement. The implication of increasing flexibility is reduced rate volatility. We find federal funds loan volume increases, but find no evidence of a reduction in federal funds rate volatility. These results are consistent with the increased carryover creating a profitable loan opportunity without changing the incentives that create the identified patterns in federal funds. We believe the difference between our results and the Federal Reserve's intention, derive from the difference in the trading behavior of the marginal and average bank.
A Simplified Dynamic Model of Parachute Inflation

This paper describes a dynamic inflation model for parachutes which predicts increased dimensionless inflation times and increased dimensionless inflation forces observed at high altitudes. As altitude is increased, greater relative parachute inertia results in increased inflation times, and greater relative total system inertia results in increased maximum inflation forces. The effect of Mach number on inflation force is also predicted by the inflation model.
Natural Ionization in Gases

Measurements of the pressure variation of the natural ionization in air, nitrogen, oxygen and carbon dioxide contained in a steel sphere of one foot inside diameter, made by H. F. Fruth for pressures from 1 to 75 atmospheres, were repeated with slight modifications. Results obtained corresponded with those of Fruth with the following exceptions: (1) although the pressure rate of variation of the natural ionization at high pressures was very small (0.4 to 1.0 ion/cc sec. atm.) no abrupt change in the rate of variation and no true "saturation" value of the ionization were observed; (2) no "anomalous" behavior was noted in the case of commercial nitrogen. Measurements to detect the variation with size of chamber were carried out with spherical iron ionization chambers of 7,9, and 12 in. respective internal diameters. The rate of production of ions per cc at high pressures did not vary unidirectionally with the size of the ionization chambers, but was least in the 9 in. sphere. To study the effect of the lining the experiments were repeated with oxygen in each of the spheres lined with aluminum of $\frac{1}{16}$ in. thickness, and in the 12 in. sphere lined with copper of $\frac{1}{16}$ in. thickness. The aluminum lining increased the ionization at low pressures, and decreased its pressure rate of variation at high pressures. The copper lining reduced the absolute value of the ionization at high pressures. The effect of water vapor on the natural ionization in aged, dust-free air, or upon its variation with pressure was found to be negligible. Both the absolute and the fractional variation of the natural ionization with time were found to depend upon the pressure, the average value of the former during a 24 hr. period being about twice and that of the latter being about $\frac{1}{5}$ as great in oxygen at 55.4 atm. pressure as in air at atmospheric pressure. Very slight evidence of a singly periodic diurnal variation in air at atmospheric pressure was observed. Attempts to determine the effects of slow chemical reactions upon the natural ionization in air and oxygen at atmospheric pressure led to negative results.
Developing extensible Lattice-Boltzmann simulators for general-purpose graphics-processing units

Lattice-Boltzmann methods are versatile numerical modeling techniques capable of reproducing a wide variety of fluid-mechanical behavior. These methods are well suited to parallel implementation, particularly on the single-instruction multiple data (SIMD) parallel processing environments found in computer graphics processing units (GPUs).Although recent programming tools dramatically improve the ease with which GPUbased applications can be written, the programming environment still lacks the flexibility available to more traditional CPU programs. In particular, it may be difficult to develop modular and extensible programs that require variable on-device functionality with current GPU architectures.This paper describes a process of automatic code generation that overcomes these difficulties for lattice-Boltzmann simulations. It details the development of GPU-based modules for an extensible lattice-Boltzmann simulation package – LBHydra. The performance of the automatically generated code is compared to equivalent purposewritten codes for both single-phase,multiphase, andmulticomponent flows. The flexibility of the new method is demonstrated by simulating a rising, dissolving droplet moving through a porous medium with user generated lattice-Boltzmann models and subroutines.
Settling the Polynomial Learnability of Mixtures of Gaussians

Given data drawn from a mixture of multivariate Gaussians, a basic problem is to accurately estimate the mixture parameters. We give an algorithm for this problem that has running time and data requirements polynomial in the dimension and the inverse of the desired accuracy, with provably minimal assumptions on the Gaussians. As a simple consequence of our learning algorithm, we we give the first polynomial time algorithm for proper density estimation for mixtures of k Gaussians that needs no assumptions on the mixture. It was open whether proper density estimation was even statistically possible (with no assumptions) given only polynomially many samples, let alone whether it could be computationally efficient. The building blocks of our algorithm are based on the work (Kalai \emph{et al}, STOC 2010) that gives an efficient algorithm for learning mixtures of two Gaussians by considering a series of projections down to one dimension, and applying the method of moments to each univariate projection. A major technical hurdle in the previous work is showing that one can efficiently learn univariate mixtures of two Gaussians. In contrast, because pathological scenarios can arise when considering projections of mixtures of more than two Gaussians, the bulk of the work in this paper concerns how to leverage a weaker algorithm for learning univariate mixtures (of many Gaussians) to learn in high dimensions. Our algorithm employs hierarchical clustering and rescaling, together with methods for backtracking and recovering from the failures that can occur in our univariate algorithm. Finally, while the running time and data requirements of our algorithm depend exponentially on the number of Gaussians in the mixture, we prove that such a dependence is necessary.
Expectation-Maximization Gaussian-Mixture Approximate Message Passing

When recovering a sparse signal from noisy compressive linear measurements, the distribution of the signal's non-zero coefficients can have a profound effect on recovery mean-squared error (MSE). If this distribution was a priori known, then one could use computationally efficient approximate message passing (AMP) techniques for nearly minimum MSE (MMSE) recovery. In practice, however, the distribution is unknown, motivating the use of robust algorithms like LASSO-which is nearly minimax optimal-at the cost of significantly larger MSE for non-least-favorable distributions. As an alternative, we propose an empirical-Bayesian technique that simultaneously learns the signal distribution while MMSE-recovering the signal-according to the learned distribution-using AMP. In particular, we model the non-zero distribution as a Gaussian mixture and learn its parameters through expectation maximization, using AMP to implement the expectation step. Numerical experiments on a wide range of signal classes confirm the state-of-the-art performance of our approach, in both reconstruction error and runtime, in the high-dimensional regime, for most (but not all) sensing operators.
Experimental Investigation of a Porous Carbon Electrode for the Removal of Mercury from Contaminated Brine

A flow(through porous electrode, made of reticulated vitreous carbon (RVC), has been designed to remove mercury from contaminated brine solutions. Experiments with a bench-scale reactor show that the mercury concentration of contaminated brine solutions can be reduced by as much as a factor of five thousand during a single pass through the electrode. The process is mass-transfer limited, and the results of the experiments are used to develop a general correlation for the dependence of the mass-transfer coefficient on the flow rate of electrolyte through RVC. In addition, the effect of counterelectrode placement on the cell resistance is examined, and the experimental data are compared to predictions from a mathematical model of the system. The model agrees favorably with the experimental results, and the benefits of upstream counterelectrode placement, indicated by the model, are verified.
Manganese and Parkinson's disease: a critical review and new findings

The goal of this review was to examine whether chronic Mn exposure produces dopamine neuron degeneration and PD or whether it has a distinct neuropathology and clinical presentation. I reviewed available clinical, neuroimaging, and neuropathological studies in humans and nonhuman primates exposed to Mn or other human conditions that result in elevated brain Mn concentrations. Human and nonhuman primate literature was examined to compare clinical, neuroimaging, and neuropathological changes associated with Mn-induced parkinsonism. Clinical, neuroimaging, and neuropathological evidence was used to examine whether Mn-induced parkinsonism involves degeneration of the nigrostriatal dopaminergic system as is the case in PD. The overwhelming evidence shows that Mn-induced parkinsonism does not involve degeneration of midbrain dopamine neurons and that l-dopa is not an effective therapy. New evidence is presented on a putative mechanism by which Mn may produce movement abnormalities. Confirmation of this hypothesis in humans is essential to make rational decisions about treatment, devise effective therapeutic strategies, and set regulatory guidelines.
Total synthesis of (±)-epicubenol

Abstract The sesquiterpenoid microbial metabolite (±)-epicubenol ( 1 ) has been synthesized in 8 steps from a readily available diene aldehyde ( 7 ) using an intramolecular Diels-Alder reaction.
Synthesis of Halomethyl and Other Bipyridine Derivatives by Reaction of 4,4‘-Bis[(trimethylsilyl)methyl]-2,2‘-bipyridine with Electrophiles in the Presence of Fluoride Ion

Bipyridine (bpy) ligands figure prominently in many areas of chemistry. Common precursors to many derivatives are the halomethyl-substituted analogues. This report describes a new, high yield route to these valuable compounds via a trimethylsilyl (TMS) intermediate. 4,4‘-Dimethyl-2,2‘-bpy was reacted with lithium diisopropylamide, and the dianion thus formed was trapped with TMSCl to generate 4,4‘-bis[(trimethylsilyl)methyl]-2,2‘-bpy (1). The TMS group was removed using dry F- sources (TBAF/SiO2 in THF or CsF in DMF) in the presence of BrF2CCF2Br or Cl3CCCl3 to produce the bromide 2 or chloride 3 analogues of 4,4‘-bis(halomethyl)-2,2‘-bipyridine, respectively. The CsF/DMF methodology extends to other electrophiles, including benzaldehyde to give 4,4‘-bis(2-hydroxy-2-phenethyl)-2,2‘-bpy, 6, as well as to alkyl halides. Benzyl Br, dodecyl Br, and α-chloroacetonitrile gave mixtures of di- and monoalkylated products along with the diprotonated product, 4,4‘-dimethyl-2,2‘-bpy.
Attracting divisors on projective algebraic varieties

We obtain sufficient and necessary conditions (in terms of positive singular metrics on an associated line bundle) for a positive divisor $D$ on a projective algebraic variety $X$ to be attracting for a holomorphic map $f:X \mapsto X$.
On determining the importance of attributes with a stopping problem

Abstract In this paper we try to answer the question of how one can determine the relative importance of the different attributes of a product. In order to answer this question a stopping problem model is constructed. An agent faces a sequence of i.i.d. multi-attribute products. From each product, he can observe only one attribute. At each period the agent has to decide whether he wants to stop and take the best product he has observed so far, or whether he prefers to continue the observation process and observe an attribute of the next product in the sequence. We find the optimal observation policy and the conditions under which it observes only one attribute, rendering it the most ‘informative’. When the sequence of products is finite, second-order stochastic dominance characterizes the case in which an optimal strategy observes only one attribute in the sense that if it holds between any two random variables induced by the expected utility given an attribute, it is never optimal to observe the ‘dominating’ attribute. When the sequence of products is infinite, observing one attribute only is always optimal. The seeming discrepancy between finite and infinite horizon models vanishes for a sufficiently large horizon, making the infinite horizon optimal attribute the one chosen for a long period in finite horizon problems as well.
Dopamine ramps are a consequence of reward prediction errors

Temporal difference learning models of dopamine assert that phasic levels of dopamine encode a reward prediction error. However, this hypothesis has been challenged by recent observations of gradually ramping stratal dopamine levels as a goal is approached. This note describes conditions under which temporal difference learning models predict dopamine ramping. The key idea is representational: a quadratic transformation of proximity to the goal implies approximately linear ramping, as observed experimentally.
Piezoelectricity in Polyacrylonitrile.

The piezoelectric and related properties in ion-doped (NH4NO3, NaNO3) and undoped films of polyacrylonitrile have been measured as a function of temperature. The piezoelectric constants of both ion-doped and undoped films reach a maximum around 80°C and thereafter decrease markedly with temperature. At about this same temperature, a maximum of thermally stimulated discharge current (TSDC) is also observed with both ion-doped and undoped films. These two effects are thought to have a common origin: the randomization of nitrile dipoles in ordered regions. The piezoelectric constant of pre-stretched films is higher than that for unstretched polyacrylonitrile.
ON THE CONNECTIVITY OF COBORDISMS AND HALF-PROJECTIVE TQFT'S

We consider a generalization of the axioms of a TQFT, the so-called half-projective TQFT's, where we inserted an anomaly, , in the composition law. Here μ0 is a coboundary (in a group cohomological sense) on the cobordism categories with non-negative, integer values. The element of the ring over which the TQFT is defined does not have to be invertible. In particular, it may be zero. This modification makes it possible to extend quantum-invariants, which vanish on S 1×S 2, to non-trivial TQFT's. Note, that a TQFT in the ordinary sense of Atiyah with this property has to be trivial all together. We organize our discussions such that the notion of a half-projective TQFT is extracted as the only possible generalization under a few very natural assumptions. Based on separate work with Lyubashenko on connected TQFT's, we construct a large class of half-projective TQFT's with . Their invariants all vanish on S 1×S 2, and they coincide with the Hennings invariant for non-semisimple Hopf algebras and, more generally, with the Lyubashenko invariant for non-semisimple categories. We also develop a few topological tools that allow us to determine the cocycle μ0 and find numbers, ϱ(M), such that the linear map associated to a cobordism, M, is of the form . They are concerned with connectivity properties of cobordisms, as for example maximal non-separating surfaces. We introduce in particular the notions of “interior” homotopy and homology groups, and of coordinate graphs, which are functions on cobordisms with values in the morphisms of a graph category. For applications we will prove that half-projective TQFT's with vanish on cobordisms with infinite interior homology, and we argue that the order of divergence of the TQFT on a cobordism, M, in the “classical limit” can be estimated by the rank of its maximal free interior group, which coincides with ϱ(M).
A move on diagrams that generates S-equivalence of knots

Two knots in three-space are S-equivalent if they are indistinguishable by Seifert matrices. We show that S-equivalence is generated by the doubled-delta move on knot diagrams. It follows as a corollary that a knot has trivial Alexander polynomial if and only if it can be undone by doubled-delta moves.
Electrodynamic response of the ionosphere to high-speed solar wind streams

[1] A combination of dawn and dusk observations from the DMSP F13 satellite and output from the thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM) are used to study the electrodynamic response of the ionosphere to quasi 9-day recurrent geomagnetic activity driven by solar wind high-speed streams during 2005. Superposed epoch analysis of the zonal and vertical plasma drifts reveal that significant electrodynamic perturbations occur in response to the high-speed streams during 2005. The peak response occurs around 0.5 days after the high-speed stream interface, and the drift perturbations slowly relax back to quiet levels over 4–6 days. The observed and modeled zonal drift perturbations are in good agreement near dusk; however, the amplitude of the zonal drift perturbations at dawn slightly differ. At low- and midlatitudes the modeled drift perturbations are westward at all local times, with the largest westward drifts occurring near midnight. At dawn, the DMSP observations at low- and midlatitudes reveal ∼20 m s−1 eastward drift perturbations, while the TIE-GCM simulates weaker eastward drifts at midlatitudes and westward drifts in the equatorial region. At dusk, the low- and midlatitude perturbation drifts are ∼10–20 m s−1 westward in both the DMSP observations and TIE-GCM simulations. Owing to equatorial expansion and strengthening of the high-latitude two-cell convection pattern, the high-latitude zonal drift perturbations are eastward in the morning and westward in the afternoon and evening. Less agreement is present between the simulated and observed vertical drift perturbations. Near dawn, at all latitudes upward drift perturbations are revealed by both the TIE-GCM simulation (∼5 m s−1) and DMSP observations (∼10–15 m s−1). However, at dusk the DMSP observes an upward drift perturbation on the order of 25–35 m s−1, while the TIE-GCM simulates vertical drift perturbations less than 10 m s−1. The disagreement may be related to errors in the DMSP observations, or deficiencies in the model. Based on the results presented, we conclude that the disturbance dynamo mechanism is an important mechanism for driving the electrodynamic response at dawn and dusk to recurrent geomagnetic activity driven by solar wind high-speed streams.
Reduced-Complexity Reed–Solomon Decoders Based on Cyclotomic FFTs

In this paper, we reduce the computational complexities of partial and dual partial cyclotomic FFTs (CFFTs), which are discrete Fourier transforms where spectral and temporal components are constrained, based on their properties as well as a common subexpression elimination algorithm. Our partial CFFTs achieve smaller computational complexities than previously proposed partial CFFTs. Utilizing our CFFTs in both transform- and time-domain Reed-Solomon decoders, we achieve significant complexity reductions.
The Necessary Maximality Principle for c.c.c. forcing is equiconsistent with a weakly compact cardinal

The Necessary Maximality Principle for c.c.c. forcing with real parameters is equiconsistent with the existence of a weakly compact cardinal. The Necessary Maximality Principle for c.c.c. forcing, denoted 2mpccc(R), asserts that any statement about a real in a c.c.c. extension that could be- come true in a further c.c.c. extension and remain true in all subsequent c.c.c. extensions, is already true in the minimal extension containing the real. We show that this principle is equiconsistent with the existence of a weakly compact cardinal. The principle is one of a family of principles considered in (Ham03) (build- ing on ideas of (Cha00) and overlapping with independent work in (SV01)). MSC: 03E55, 03E40. Keywords: forcing axiom, ccc forcing, weakly compact cardinal. The first author is affiliated with the College of Staten Islandof CUNY and The CUNY Graduate Center, and his research has been supported by grants from the Research Foun- dation of CUNY and the National Science Foundation DMS-9970993. The research of the second author has been partially supported by National Science Foundation grant DMS-9970255.
A novel aquaretic and GFR enhancing peptide without vascular vasodilatory actions in experimental CHF

Background: BNP is a cardiac peptide with vasodilatory, natriuretic and diuretic properties. Recent studies have suggested that its vasodilatory hypotensive properties may limit the renal actions of BNP, especially in patients with borderline low blood pressure. We have recently identified an alternatively spliced transcript for BNP (ASBNP) that includes a unique and distinct longer carboxyl-terminus consisting of 34 amino acids. Based upon preliminary studies, we generated a truncated form (ASBNP2.1) that contains the first 16 amino acids of the C-terminal of ASBNP. Method: We determined the cardiorenal and humoral actions of intravenous infusion of ASBNP2.1 at 2 pmol/kgmin, 10 pmol/kgmin and 100pmol/kgmin in 10 dogs with rapid ventricular pacing induced overt CHF (240 bpm for 10 days) (*p< 0.05). Results: IV infusion of ASBNP 2.1 increased aquaresis (from 0.19± 0.04 to 0.32± 0.07, 0.46± 0.11 and 0.39± 0.09ml/min*) without a significant change in urinary sodium excretion. Importantly, ASBNP 2.1 enhanced glomerular filtration rate (GFR), from 31± 4 to 47± 8, Titration of medications byHF nurses increases optimisation doses of key therapeutic agents
Alterations in Preload and Myocardial Mechanics in the Dog and in Man

Based on a myocardial mechanics approach to the analysis of left ventricular contraction, several indexes have been advanced as specific measures of myocardial contractility. Although two of these indexes, Vmax and [(dP/dt)/P]max, have been shown to be appropriately responsive to interventions known to alter the inotropic state, controversy has arisen as to whether they are unaffected by alterations in preload or initial cardiac muscle fiber length. This study was undertaken to determine which, if any, of the indexes obtained from myocardial mechanics analysis of left ventricular systole is independent of preload in the intact heart. Increases in left ventricular enddiastolic pressure were produced in seven dogs by infusion of dextran or whole blood and in eight patients by sudden elevation of the legs during cardiac catheterization. In dogs, elevation of left ventricular end-diastolic pressure was accompanied by a progressive decline in both Vmax and [(dP/dt)/P]max measured using total pressure (P < 0.01...
Compressed Sensing With Cross Validation

Compressed sensing (CS) decoding algorithms can efficiently recover an N -dimensional real-valued vector x to within a factor of its best k-term approximation by taking m = O(klogN/k) measurements y = Phix. If the sparsity or approximate sparsity level of x were known, then this theoretical guarantee would imply quality assurance of the resulting CS estimate. However, because the underlying sparsity of the signal x is unknown, the quality of a CS estimate \mathhat x using m measurements is not assured. It is nevertheless shown in this paper that sharp bounds on the error ||x - \mathhat x ||lN2 can be achieved with almost no effort. More precisely, suppose that a maximum number of measurements m is preimposed. One can reserve 10 log p of these m measurements and compute a sequence of possible estimates (\mathhat xj)j=1p to x from the m -10logp remaining measurements; the errors ||x - \mathhat xj ||lN2 for j = 1, ..., p can then be bounded with high probability. As a consequence, numerical upper and lower bounds on the error between x and the best k-term approximation to x can be estimated for p values of k with almost no cost. This observation has applications outside CS as well.
How Is Reliability Related to the Quality of Test Scores? What Is the Effect of Local Dependence on Reliability?

What are the practical implications of small decreases in reliability coefficients? How does increased item local dependence decrease reliability? How does the new format of more “authentic” reading tests affect reliability?
Reducing the 4d index to the S 3 partition function

The superconformal index of a 4d gauge theory is computed by a matrix integral arising from localization of the supersymmetric path integral on S 3 × S 1. As the radius of the circle goes to zero, it is natural to expect that the 4d path integral becomes the partition function of dimensionally reduced gauge theory on S 3. We show that this is indeed the case and recover the matrix integral of Kapustin, Willett and Yaakov from the matrix integral that computes the superconformal index. Remarkably, the superconformal index of the “parent” 4d theory can be thought of as the q-deformation of the 3d partition function.
HIGH-FIELD MAGNETOTRANSPORT STUDIES OF FERROMAGNETIC GaAs/Mn DIGITAL ALLOYS

Magnetotransport properties of ferromagnetic GaAs/Mn digital alloys have been investigated in fields up to 33 T. A series of four GaAs/Mn digital alloys with different Mn coverages (0.15 ML - 0.5 ML) at fixed GaAs spacer thickness (9 ML), with Curie temperatures, TC, between 20 and 40 K shows hopping conduction behavior in the zero-field sheet resistance below TC. Analysis of the high field magnetotransport measurements on these samples reveals hole densities between 0.45×1013 and 1.8×1013cm-2/Mn layer at 5 K. In contrast, a GaAs/Mn digital alloy with slightly different parameters (0.5 ML Mn and 14 ML GaAs spacer layers) and growth conditions shows essentially metallic behavior and much higher TC (60 K). The zero-field sheet resistance, although decreasing weakly with T at low temperatures, cannot be fit by a hopping expression. From analysis of Shubnikov-de Haas oscillations observed in this sample, an effective mass of ≈0.31m0 was determined, close to the heavy hole mass of GaAs. The hole density extracted from fits to RHall at high fields is comparable to that of the insulating GaAs/Ma digital alloys at the same Mn coverage. This suggests that the increased metallicity is the most important factor in significantly enhancing TC.
The Stellar Populations in the Outer Regions of M33. I. Metallicity Distribution Function

We present deep CCD photometry in the VI passbands using the WIYN 3.5 m telescope of a field located approximately 20' southeast of the center of M33; this field includes the region studied by Mould & Kristian in 1986. The color-magnitude diagram (CMD) extends to I ~ 25 and shows a prominent red giant branch (RGB), along with significant numbers of asymptotic giant branch and young main-sequence stars. The red clump of core helium burning stars is also discernable near the limit of our CMD. The I-band apparent magnitude of the red giant branch tip implies a distance modulus of (m - M)I = 24.77 ± 0.06, which combined with an adopted reddening of E(V-I) = 0.06 ± 0.02 yields an absolute modulus of (m - M)0 = 24.69 ± 0.07 (867 ± 28 kpc) for M33. Over the range of deprojected radii covered by our field (from about 8.5 to about 12.5 kpc), we find a significant age gradient with an upper limit of ~1 Gyr (~0.25 Gyr kpc-1). Comparison of the RGB photometry with empirical giant branch sequences for Galactic globular clusters allows us to use the dereddened color of these stars to construct a metallicity distribution function (MDF). The primary peak in the MDF is at a metallicity of [Fe/H] ~ -1.0 with a tail to lower abundances. The peak does show radial variation with a slope of Δ[Fe/H]/ΔRdeproj = -0.06 ± 0.01 dex kpc-1. This gradient is consistent with the variation seen in the inner disk regions of M33. As such, we conclude that the vast majority of stars in this field belong to the disk of M33, not the halo as previously thought.
Coupled nongray radiating flows about long blunt bodies

Time asymptotic solutions for hypervelocity blunt body flow field with coupled nongray radiation, treating shock as discrete surface
Brownian dynamics of a sphere between parallel walls

We describe direct imaging measurements of a colloidal sphere's diffusion between two parallel surfaces. The dynamics of this deceptively simple hydrodynamically coupled system have proved difficult to analyze. Comparison with approximate formulations of a confined sphere's hydrodynamic mobility reveals good agreement with both a leading-order superposition approximation as well as a more general all-images stokeslet analysis.
Hans albert einstein in South Carolina

In October 1937, a few months after completing his doctoral studies at the Eidgenossische Technische Hochschule ETH in Zurich, Switzerland, Hans Albert Einstein stepped off the boat in New York, where he was met by his father, the famous physicist Albert Einstein Fig. 1 . Getting his 33-years-old son from Switzerland to the United States had been a major effort for Albert. His son needed to learn English; his son’s wife was reluctant to leave Switzerland; acquiring the right visa was complicated; moreover, there was concern that his son as the son of a prominent Jewish scientist should avoid traveling on a German ship. Albert then had the task of finding his son a job in the United States. Albert called upon acquaintances to assist in finding his son a position. Professors Theodore von Karman at Caltech and Lewis Moody at Princeton played crucial roles in identifying possible employers. In due course, after visiting several agencies and universities, Hans Albert Einstein hereinafter called Einstein filtered down through the bureaucratic structure of the U.S. Department of Agriculture USDA and spoke with someone who could
Efficient and flexible matching of recursive types

Equality and subtyping of recursive types were studied in the 1990s by Amadio and Cardelli; Kozen, Palsberg, and Schwartzbach; Brandt and Henglein; and others. Potential applications include automatic generation of bridge code for multilanguage systems and type-based retrieval of software modules from libraries. In this paper, we present an efficient decision procedure for a notion of type equality that includes unfolding of recursive types, and associativity and commutativity of product types. Advocated by Auerbach, Barton, and Raghavachari, these properties enable flexible matching of types. For two types of size at most n, our algorithm takes O (n) iterations each of which takes O (n) time, for a total of O (n2) time. 2001 Elsevier Science
The enrichment history of baryons in the Universe

We present predictions for the cosmic metal budget in various phases of baryons from redshift z = 6 → 0, taken from a cosmological hydrodynamic simulation that includes a well-constrained model for enriched galactic outflows. We find that substantial amounts of metals are found in every baryonic phase at all epochs, with diffuse intergalactic gas dominating the metal budget at early epochs and stars and halo gas dominating at recent epochs. We provide a full accounting of metals in the context of the missing metals problem at z ≈ 2.5, showing that ∼40 per cent of the metals are in galaxies, and the remainder are divided between diffuse intergalactic medium (IGM) gas and shocked gas in haloes and filamentary structures. Comparisons with available observations of metallicity and metal mass fraction evolution show broad agreement. We predict that stars have a mean metallicity of one-tenth solar already at z = 6, which increases slowly to one-half solar today, while stars just forming today typically have solar metallicity. Our H 1 column density weighted mean metallicity (comparable to damped Lyman a system metallicities) slowly increases from one-tenth to one-third solar from z = 6 → 1, and then falls to one-quarter solar at z = 0. The global mean metallicity of the universe tracks ∼50 per cent higher than that of the diffuse phase down to z ∼ 1, and by z = 0 it has a value around one-tenth solar. Metals move towards higher densities and temperatures with time, peaking around the mean cosmic density at z = 2 and an overdensity of 100 at z = 0. We study how carbon and oxygen ions trace the path of metals in phase space, and show that O III -O VII lines provide the most-practical option for constraining IGM metals at z ≤ 2.
X-Ray Variability Characteristics of the Seyfert 1 Galaxy NGC 3783

We have characterized the energy-dependent X-ray variability properties of the Seyfert 1 galaxy NGC 3783 using archival XMM-Newton and Rossi X-Ray Timing Explorer data. The high-frequency fluctuation power spectral density function (PSD) slope is consistent with flattening toward higher energies. Light-curve cross-correlation functions yield no significant lags, but peak coefficients generally decrease as energy separation of the bands increases on both short and long timescales. We have measured the coherence between various X-ray bands over the temporal frequency range of 6 × 10-8-1 × 10-4 Hz; this range includes the temporal frequency of the low-frequency PSD break tentatively detected by Markowitz et al. and includes the lowest temporal frequency over which coherence has been measured in any active galactic nucleus to date. Coherence is generally near unity at these temporal frequencies, although it decreases slightly as energy separation of the bands increases. Temporal frequency-dependent phase lags are detected on short timescales; phase lags are consistent with increasing as energy separation increases or as temporal frequency decreases. All of these results are similar to those obtained previously for several Seyfert galaxies and stellar mass black hole systems. Qualitatively, these results are consistent with the variability models of Kotov et al. and Lyubarskii, wherein the X-ray variability is due to inwardly propagating variations in the local mass accretion rate.
The application of formyl group activation of bromopyrrole esters to formal syntheses of lycogarubin C, permethyl storniamide A and lamellarin G trimethyl ether

Lycogarubin C, permethyl storniamide A and lamellarin G trimethyl ether are pyrrole containing, natural products, which exhibit interesting biological properties. Such properties include anti-tumor activity on a variety of cancer cell lines including those that confer drug resistance, inhibition of HIV integrase and vascular disrupting activity. We now describe the use of methyl and ethyl 3-bromo-2-formylpyrrole-5-carboxylate as building blocks for the formal synthesis of these three highly functionalized, bioactive pyrroles. These new building blocks will now provide ready access to the natural products and many novel analogs due to the ability to easily modify positions 2,3,4 and 5 of the pyrrole core.
New approaches to antidepressant drug discovery: beyond monoamines

All antidepressants in use today act via the monoamine neurotransmitters. However, only ∼50% of individuals with depression show full remission. Berton and Nestler review recent development of alternative, non-monoamine-based antidepressants, highlighting the obstacles and some of the most promising strategies. All available antidepressant medications are based on serendipitous discoveries of the clinical efficacy of two classes of antidepressants more than 50 years ago. These tricyclic and monoamine oxidase inhibitor antidepressants were subsequently found to promote serotonin or noradrenaline function in the brain. Newer agents are more specific but have the same core mechanisms of action in promoting these monoamine neurotransmitters. This is unfortunate, because only ∼50% of individuals with depression show full remission in response to these mechanisms. This review summarizes the obstacles that have hindered the development of non-monoamine-based antidepressants, and provides a progress report on some of the most promising current strategies.
Aggressive behavior of chimpanzees and baboons in natural habitats.

Publisher Summary This chapter discusses the aggressive behavior of chimpanzees and baboons in natural habitats. The predator–prey relation is only one aspect of the complex interactions between chimpanzees and baboons at the Gombe Stream Reserve and certainly not the most prominent aspect on a day-to-day basis. The two species clearly know each other well and they respond to each other differentially in a way that suggests the recognition of individual animals, the recognition of signals, and mutual accommodation. Overt competition sometimes occurs, especially in relation to premium foods. It is found that while the chimpanzees are generally dominant over the baboons in these encounters, the interactions are complex. Several adult male baboons may persist for several hours in harassing adult male chimpanzees who are controlling a supply of bananas. This harassment involves repeated, close-range threats, including the display of the massive canine teeth. Occasional short runs to grab for a banana also occur. However, the baboons rarely get more than a banana peel, at least until the chimpanzees have had an abundant intake. In these persistent agonistic encounters over a premium food, baboons frequently break off contact with the adult male chimpanzees and attack a female or juvenile chimpanzee.
Geometric phase for single-photon mixed polarization states

The resilience of geometric phase against errors may enable fault-tolerant quantum computation. We use an interferometric scheme to measure geometric phases of various mixed polarization states generated classically and from conditionally prepared (entangled) single photons
THREE NEW MALYNGAMIDES FROM THE MARINE CYANOBACTERIUM LYNGBYA MAJUSCULA

Abstract Three new malyngamides, J (1), K (2) and L (3), all amides of 7(S)-methoxytetradec-4(E)-enoic acid, were isolated from Curacao collections of Lyngbya majuscula. The structures of these new malyngamides were elucidated on the basis of 1D and 2D NMR spectroscopic analysis of the natural products and key derivatives. The stereochemistry of malyngamide J (1) was probed by NMR and exciton chirality circular dichroism spectroscopy.
Two-level modeling framework for pedestrian route choice and walking behaviors

Abstract A microscopic two-level simulation modeling framework is proposed to analyze both decision-making processes at a crosswalk as well as physical interactions among pedestrians when they cross a street. The model at the higher level is based on Decision Field Theory to represent the psychological preferences of pedestrians with respect to different route choice options during their deliberation process after evaluating current surroundings. At the lower level, physical interactions among pedestrians and consequent congestions are represented using a Cellular Automata model, in which pedestrians are allowed biased random-walking without back step towards their destination that has been given by the higher level model. A typical crosswalk with split sidewalks in the Chicago Loop area is employed as a case study, which has been implemented in AnyLogic® software. Weekday pedestrian counts on the 15-min basis near the studied crosswalk have been collected and used to construct and validate the simulation models. Experiments have been conducted to investigate the impact of corresponding environment parameters, such as pedestrian types and green/red phase length, as well as social parameters such as leadership in group decision making, on the average pedestrian waiting time at the crosswalk. Initial results look quite interesting. An extension on coupling the proposed pedestrian model with a transportation simulation model is also briefly discussed.
Knowledge-based understanding of radiology text

Abstract A data acquisition tool which will extract pertinent diagnostic information from radiology reports has been designed and implemented. Pertinent diagnostic information is defined as that clinical data which is used by the HELP medical expert system. The program uses a memory-based semantic parsing technique to ‘understand’ the text. Moreover, the memory structures and lexicon necessary to perform this action are automatically generated from the diagnostic knowledge base by using a special purpose compiler. The result is a system where data extraction from free text is directed by an expert system whose goal is diagnosis.
Symbolic reachability analysis for parameterized administrative role-based access control

Role-based access control (RBAC) is a widely used access control paradigm. In large organizations, the RBAC policy is managed by multiple administrators. An administrative role-based access control (ARBAC) policy specifies how each administrator may change the RBAC policy. It is often difficult to fully understand the effect of an ARBAC policy by simple inspection, because sequences of changes by different administrators may interact in unexpected ways. ARBAC policy analysis algorithms can help by answering questions, such as user-role reachability, which asks whether a given user can be assigned to given roles by given administrators. Allowing roles and permissions to have parameters significantly enhances the scalability, flexibility, and expressiveness of ARBAC policies. This paper defines PARBAC, which extends the classic ARBAC97 model to support parameters, proves that user-role reachability analysis for PARBAC is undecidable when parameters may range over infinite types, and presents a semi-decision procedure for reachability analysis of PARBAC. To the best of our knowledge, this is the first analysis algorithm specifically for parameterized ARBAC policies. We evaluate its efficiency by analyzing its parameterized complexity and benchmarking it on case studies and synthetic policies. We also experimentally evaluate the effectiveness of several optimizations.