cssi/SciSciGPT-SciSciNet huggingface dataset:
4D and 2D superconformal index with surface operator

We study the superconformal index of the N = 4 super-Yang-Milles theory on S^3 × S^1 with the half BPS superconformal surface operator (defect) inserted at the great circle of S^3. The half BPS superconformal surface operators preserve the same supersymmetry as well as the symmetry of the chemical potential used in the definition of the superconformal index, so the structure and the parameterization of the superconformal index remain unaffected by the presence of the surface operator. On the surface defect, a two-dimensional (4, 4) superconformal field theory resides, and the four-dimensional superconformal index may be regarded as a superconformal index of the two-dimensional (4, 4) superconformal field theory coupled with the four-dimensional bulk system. We construct the matrix model that computes the superconformal index with the surface operator when it couples with the bulk N = 4 super-Yang-Milles theory through the defect hypermultiplets on it.
Model misspecification tests, model building and predictability in complex systems

Abstract In this paper we show that significant advantages can be realized by using functions of simple variables, such as time lags, as directions in reconstruction spaces for complicated time series. First, we show that more sensitive model misspecification tests can be constructed when the candidate model is used as one of the directions in the reconstruction space. This naturally results in misspecification tests based on the construction of conditional probabilities which can reveal misspecified models even when other powerful methods, such as the BDS test applied to a sequence of residuals, fails. Second, we show that model building and predictability of the time series can be substantially improved by using an informational criterion to determine the functions with which to associate the directions of the reconstruction space. This criterion is of the form of a conditional probability and is related to a measure of the short term predictability of the time series. We consider specifically an example in which the search space of functions is linear combinations of time-lags, and we compare the resulting model with a linear least squares fit to the data. We also show that this optimized reconstruction space can improve longer-term predictability. We demonstrate this by comparing longer-term predictions made using the optimized space with predictions made using a simple time-lagged reconstruction space.
Randomized allocation processes

Many dynamic resource allocation and on-line load balancing problems can be modeled by processes that sequentially allocate balls into bins. The balls arrive one by one and are to be placed into bins on-line without using a centralized controller. If n balls are sequentially placed into n bins by placing each ball in a randomly chosen bin, then it is widely known that the maximum load in bins is ln n /ln ln n⋅(1+o(1)) with high probability. Azar, Broder, Karlin, and Upfal extended this scheme, so that each ball is placed sequentially into the least full of d randomly chosen bins. They showed that the maximum load of the bins reduces exponentially and is ln ln n/In d+Θ(1) with high probability, provided d<2. In this paper we investigate various extensions of these schemes that arise in applications in dynamic resource allocation and on-line load balancing. Traditionally, the main aim of allocation processes is to place balls into bins to minimize the maximum load in bins. However, in many applications it is equally important to minimize the number of choices performed (the allocation time). We study adaptive allocation schemes that achieve optimal tradeoffs between the maximum load, the maximum allocation time, and the average allocation time. We also investigate allocation processes that may reallocate the balls. We provide a tight analysis of a natural class of processes that each time a ball is placed in one of d randomly chosen bins may move balls among these d bins arbitrarily. Finally, we provide a tight analysis of the maximum load of the off-line process in which each ball may be placed into one of d randomly chosen bins. We apply this result to competitive analysis of on-line load balancing processes. ©2001 John Wiley & Sons, Inc. Random Struct. Alg., 18: 297–331, 2001
Core formation, evolution, and convection - A geophysical model

We propose a model for the formation and evolution of the Earth's core which provides an adequate energy source for maintaining the geodynamo. A modified inhomogeneous accretion model is proposed which leads to initial iron and refractory enrichment at the center of the planet. The probable heat source for melting of the core is the decay of ^(26)Al. The refractory material is emplaced irregularly in the lowermost mantle with uranium and thorium serving as a long-lived heat source. Fluid motions in the core are driven by the differential heating from above and the resulting cyclonic motions may be the source of the geodynamo.
When Does Privatization Work? The Impact of Private Ownership on Corporate Performance in the Transition Economies

This paper compares the performance of privatized and state firms in the transition economies of Central Europe, while controlling for various forms of selection bias. It argues that privatization has different effects depending on the types of owners to whom it gives control. In particular, privatization to outsider, but not insider, owners has significant performance effects. Where privatization is effective, the effect on revenue performance is very pronounced, but there is no comparable effect on cost reduction. Overlooking the strong revenue effect of privatization to outsider owners leads to a substantial overstatement of potential employment losses from postprivatization restructuring.
An intersectional approach to diversity research

Diversity can be analyzed using one of two approaches. The dominant unidimensional approach examines diversity across a single dimension at a time (e.g. first by race, then by sex). By contrast, an emerging intersectional approach considers diversity across multiple dimensions at once (e.g. by race and sex). This article presents a visual study of marketing images using unidimensional and intersectional approaches to reveal the strengths and weaknesses of both approaches. Unidimensional research proves much easier to conduct, but its conclusions tend to be simplistic, misleading, and repressive. By contrast, intersectional research is cumbersome, but its relatively complex conclusions are more inclusive, precise, and radical. Only intersectional research can reveal how the multiply disadvantaged are often completely erased (intersectional invisibility) or disproportionately ridiculed (intersectional travesty), drawing overdue attention to the market's most marginalized segments.
Using electronic conductivity and hardness data for rapid assessment of stream water quality.

Abstract A graphical screening method was previously developed by Kney and Brandes (2007) for assessing stream water quality data using electronic conductivity (EC) and alkalinity data. The method was aimed at providing citizen scientists involved in stream monitoring programs with a relatively simple way to interpret EC data. The method utilizes a plot of EC against concurrent alkalinity data, and is used to distinguish EC values for impacted or degraded streams from those that can be considered background values in a particular geologic setting. The method performs well in areas underlain by carbonate bedrock, as streams in those areas characteristically have EC values that are strongly correlated with alkalinity. However, in areas of low stream alkalinity (less than approximately 50 mg/L as CaCO 3 ), the Kney and Brandes (2007) method was found to be much less effective in identifying impacted streams. This paper extends the graphical screening approach to streams with low alkalinity, specifically regions underlain by clastic sedimentary or crystalline bedrock, by using the strong correlation between EC and total hardness (TH). A baseline relationship of EC vs. TH is developed using surface water chemistry data from Hydrologic Benchmark Network streams (deemed as having minimal anthropogenic impacts) and regional groundwater quality data. The usefulness of the method is demonstrated by application to publicly available stream chemistry data and to field data collected from streams of eastern Pennsylvania under baseflow conditions. Results demonstrate that for streams with alkalinity 3 , the TH-based graphical screening method should be used rather than the alkalinity-based method of Kney and Brandes (2007).
Synthesis and antitumor activity of a series of 1,2-diaminocyclohexanepalladium(II) dicarboxylate complexes

Abstract A series of complexes of the type [Pd(O O(DACH)] (O O = dicarboxylate ligand, DACH = 1,2-diaminocyclohexane) has been prepared. These complexes have been characterized by elemental analysis and infrared spectroscopy. The complexes have been screened in vivo for antitumor activity against the L1210 leukemia cell line. These palladium complexes lack antitumor activity, which may be due to (1) lack of solubility and/or (2) lack of stability of the complexes in solution.
Optimal hierarchical layouts for cache-oblivious search trees

This paper proposes a general framework for generating cache-oblivious layouts for binary search trees. A cache-oblivious layout attempts to minimize cache misses on any hierarchical memory, independent of the number of memory levels and attributes at each level such as cache size, line size, and replacement policy. Recursively partitioning a tree into contiguous subtrees and prescribing an ordering amongst the subtrees, Hierarchical Layouts generalize many commonly used layouts for trees such as in-order, pre-order and breadth-first. They also generalize the various flavors of the van Emde Boas layout, which have previously been used as cache-oblivious layouts. Hierarchical Layouts thus unify previous attempts at deriving layouts for search trees. The paper then derives a new locality measure (the Weighted Edge Product) that mimics the probability of cache misses at multiple levels, and shows that layouts that reduce this measure perform better. We analyze the various degrees of freedom in the construction of Hierarchical Layouts, and investigate the relative effect of each of these decisions in the construction of cache-oblivious layouts. Optimizing the Weighted Edge Product for complete binary search trees, we introduce the MINWEP layout, and show that it outperforms previously used cache-oblivious layouts by almost 20%.
Cyclic systems of simultaneous congruences

This paper considers the cyclic system of n ≥ 2 simultaneous congruences for fixed nonzero integers (r, s) with r > 0 and (r, s) = 1. It shows there are only finitely many solutions in positive integers qi ≥ 2, with gcd(q1q2 ⋯ qn, s) = 1 and obtains sharp bounds on the maximal size of solutions for almost all (r, s). The extremal solutions for r = s = 1 are related to Sylvester's sequence 2, 3, 7, 43, 1807,…. If the positivity condition on the integers qi is dropped, then for r = 1 these systems of congruences, taken (mod|qi|), have infinitely many solutions, while for r ≥ 2 they have finitely many solutions. The problem is reduced to studying integer solutions of the family of Diophantine equations depending on three parameters (r, s, m).
Thermocapillary flow with evaporation and condensation at low gravity. Part 2. Deformable surface

The free surface behavior of a volatile wetting liquid at low gravity is studied using scaling and numerical techniques. An open cavity model, which was applied in part 1 to investigate fluid flow and heat transfer in non-deforming pores, is used to evaluate the influence of convection on surface morphology with length scales and subcooling/superheating limits of 1 less than or equal to D less than or equal to 10(exp 2) microns and approximately 1 K, respectively. Results show that the menisci shapes of highly wetting fluids are sensitive to thermocapillary flow and to a lesser extent the recoil force associated with evaporation and condensation. With subcooling, thermocapillarity produces a suction about the pore centerline that promotes loss of mechanical equilibrium, while condensation exerts an opposing force that under some conditions offsets this destabilizing influence. With superheating, thermocapillarity and evaporation act in the same direction and mutually foster surface stability. All of these trends are magnified by high capillary and Biot numbers, and the stronger circulation intensities associated with small contact angles. These phenomena strongly depend on the thermal and interfacial equilibrium between the liquid and vapor, and have important ramifications for systems designed to maintain a pressure differential across a porous surface.
Subsonic mechanical alignment of irregular grains

We show that grains can be efficiently aligned by interacting with a subsonic gaseous flow. The alignment arises from grains having irregularities that scatter atoms with different efficiency in the right and left directions. The grains tend to align with long axes perpendicular to magnetic field, which corresponds to Davis-Greenstein predictions, but does not involve paramagnetic dissipation. Choosing conservative estimates of the scattering efficiency of impinging atoms and a conservative ``degree of helicity'' of grains, the alignment of helical grains is much more efficient than the Gold-type alignment processes.
Periodic Monopoles With Singularities And N = 2 Super-QCD

We study solutions of the Bogomolny equation on ℝ2×𝕊1 with prescribed singularities. We show that the Nahm transform establishes a one-to-one correspondence between such solutions and solutions of the Hitchin equations on a punctured cylinder with the eigenvalues of the Higgs field growing at infinity in a particular manner. The moduli spaces of solutions have natural hyperkahler metrics of a novel kind. We show that these metrics describe the quantum Coulomb branch of certain 𝒩=2 d=4 supersymmetric gauge theories on ℝ3×𝕊1. The Coulomb branches of the corresponding uncompactified theories have been previously determined by E. Witten using the M-theory fivebrane. We show that the Seiberg-Witten curves of these theories are identical to the spectral curves associated to solutions of the Bogomolny equation on ℝ2×𝕊1. In particular, this allows us to rederive Witten's results without recourse to the M-theory fivebrane.
Catalytic Hydrogenation of L-Ascorbic Acid (Vitamin C): A Stereoselective Process for the Production of L-Gulono-1, 4-Lactone

Abstract Reduction of functional groups with hydrogen gas is one of the most important reactions in organic chemistry, dating to the first hydrogenation of ethene to ethane reported by Von Wilde in 18741. Indeed, alkenes are generally rapidly hydrogenated, in the presence of a catalyst, usually, platinum, Raney nickel, palladium, or rhodium on carbon, to the corresponding alkane via heterogeneous reaction. Most undergraduate, introductory texts introduce this reaction as occurring via a stermspecific syn addition, although this is an oversimplification, due to possible rearrangements on the catalyst surface2. While the chemistry of Vitamin C (L-ascorbic acid), in regards to oxidative degradation, is well studied, its behavior under reductive conditions has been relatively overlooked. The catalytic reduction of ascorbic acid has been reported earlier (24 hours, palladium catalyst, water, 50°) by workers at Pfizer3.
Rotordynamic Stability Predictions for Centrifugal Compressors Using a Bulk-Flow Model to Predict Impeller Shroud Force and Moment Coefficients

An analysis is developed for a compressible bulk-flow model of the leakage path between a centrifugal-compressor impeller’s shroud and its housing along the impeller’s front and back sides. This development is an extension of analyses performed first by Childs (1989, ASME J. Vib. Acoust., Stress, Reliab. Des., 111, pp. 216–225) for pump impellers. The bulk-flow model is used to predict reaction force and moment coefficients for the impeller shroud. A labyrinth seal code developed by Childs and Scharrer ( 1986, ASME Trans. J. Eng. Gas Turbines Power, 108, pp. 325–331) is used to calculate the rotordynamic coefficients developed by the labyrinth seals in the compressor stage and also provides a boundary condition for the shroud calculations. Comparisons between the measured shroud moment coefficients by Yoshida (1996, Proceedings of the 6th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, 2, pp. 151–160) and model predictions show reasonable agreements for the clearance flow and reaction moments. For the conditions considered, low Mach number flow existed in the shroud clearance areas and compressible-flow and incompressible-flow models produced similar predictions. Childs’ model predictions for the direct damping and cross-coupled stiffness coefficients of a pump impeller produced reasonable agreement; hence the present model was validated to the extent possible. A rotor model consisting of an overhung impeller stage supported by a nominally cantilevered rotor was analyzed for stability using the present bulk-flow model and an API standard Wachel–von Nimitz formula model (1981, J. Petrol. Technol., pp. 2252–2260). The bulk-flow model predicted significantly higher onset speeds of instability. Given that some compressors have been predicted to be comfortably stable using API standard Wachel–von Nimitz formula but have been unstable on the test stand, these results suggest that unidentified destabilizing forces and or moments are present in compressors. Seal rub conditions that arise from surge events and increase the seal clearances are simulated, showing that enlarged clearances increase the preswirl at the seals, thus increasing these seal’s destabilizing forces and reducing stability margins. These results are consistent with field experience. Predictions concerning the back shroud indicate that shunt-hole injection mainly acts to enhance stability by changing the flow field of the division wall or balance piston seals, not by influencing the back-shroud’s forces or moments. Effective swirl brakes at these seals also serve this purpose.
Synthesis of annelated pyridines from 1,5-diketone equivalents using cupric acetate and ammonium acetate

Abstract Cupric acetate serves as a mild oxidant in the efficient synthesis of 1,2,3,4,5,6,7,8-octahydroacridines 2 and 7 from a 1,5-diketone (6) a ketoalcohol (1) or a 4H-pyran (5) using ammonium acetate in acetic acid.
Strong nuclear enhancement in intermediate mass Drell–Yan production

Abstract We calculate nuclear effect in Drell–Yan massive lepton-pair production in terms of parton multiple scattering in Quantum Chromodynamics (QCD). We present the nuclear modification to inclusive Drell–Yan cross section dσ / dQ 2 in terms of multiparton correlation functions. By extracting the size of the correlation functions from measured Drell–Yan transverse momentum broadening in nuclear medium, we determine the nuclear modification at O ( α s / Q 2 ). We find that the nuclear modification strongly enhances the inclusive Drell–Yan cross section in the intermediate mass region (IMR): 1.5 Q
The Cauchy problem for wave maps on a curved background

We consider the Cauchy problem for wave maps $${u: {\mathbb R}\times M \to N,}$$ for Riemannian manifolds (M, g) and (N, h). We prove global existence and uniqueness for initial data, u[0] = (u 0, u 1), that is small in the critical norm $${\dot{H}^{\frac{d}{2}}\times \dot{H}^{\frac{d}{2}-1}(M; TN),}$$ in the case (M, g) = $${({\mathbb R}^4, g),}$$ where g is a small perturbation of the Euclidean metric. The proof follows the method introduced by Statah and Struwe in (Commun Pure Appl Math 47(5):719–754, 1994) for proving global existence and uniqueness of small data wave maps $${u : {\mathbb R}\times {\mathbb R}^d \to N}$$ in the critical norm, for d ≥ 4. In our argument we employ the Strichartz estimates for variable coefficient wave equations established by Metcalfe and Tataru in (To appear in Math Ann).
Holographic gravitational anomalies

In the AdS/CFT correspondence one encounters theories that are not invariant under diffeomorphisms. In the boundary theory this is a gravitational anomaly, and can arise in 4k+2 dimensions. In the bulk, there can be gravitational Chern-Simons terms which vary by a total derivative. We work out the holographic stress tensor for such theories, and demonstrate agreement between the bulk and boundary. Anomalies lead to novel effects, such as a nonzero angular momentum for global AdS3. In string theory such Chern-Simons terms are known with exact coefficients. The resulting anomalies, combined with symmetries, imply corrections to the Bekenstein-Hawking entropy of black holes that agree exactly with the microscopic counting.
Radical pair recombination stereoselectivity as a probe of magnetic isotope and magnetic field effects

Photolysis of meso- or dl-2,4-diphenylpentan-3-one within NaY zeolites, coadsorbed with a chiral inductor, lead to enantioselective radical pair recombinations which are sensitive to 13C isotope effects, but insensitive towards external magnetic field effects.
A Stereodivergent Approach to (−)-α-Kainic Acid and (+)-α-Allokainic Acid Utilizing the Complementarity of Alkyne and Allene Cyclizations

A formal synthesis of (+)-α-allokainic acid and a total synthesis of (−)-α-kainic acid were carried out using a short, efficient, and highly stereoselective approach. From an alkyne precursor, a nickel-catalyzed cyclization and a palladium-catalyzed rearrangement were utilized in the synthesis of (+)-α-allokainic acid. From an allene precursor, a nickel-catalyzed cyclization was utilized in the synthesis of (−)-α-kainic acid. The allene cyclization used in the latter sequence was the first example of a metal-catalyzed cyclization of this type.
Atmospheric Turbulence Measurements with the Palomar Testbed Interferometer

Data from the Palomar Testbed Interferometer, with a baseline length of 110 m and an observing wavelength of 2.2 μm, were used to derive information on atmospheric turbulence on 64 nights in 1999. The measured two-aperture variance coherence times at 2.2 μm ranged from 25 to 415 ms (the lower value was set by instrumental limitations—the interferometer could not operate when the coherence time was lower than this). On all nights, the spectrum of the short-timescale (less than 600 ms) delay fluctuations had a shallower spectrum than the theoretical Kolmogorov value of 5/3. On most nights, the mean value of the power-law slope was between 1.40 and 1.50. Such a sub-Kolmogorov slope will result in the seeing improving as the ≈0.4 power of wavelength, rather than the slower 0.2 power predicted by Kolmogorov theory. On four nights, the combination of delay and angle-tracking measurements allowed a derivation of the (multiple) wind velocities of the turbulent layers, for a frozen-flow model. The derived wind velocities were all ≤4 m s-1, except for a small 10 m s-1 component on one night. The combination of measured coherence time, turbulence spectral slope, and wind velocity for the turbulent layer(s) allowed a robust solution for the outer scale size (beyond which the fluctuations do not increase). On the four nights with angle-tracking data, the outer scale varied from 6 to 54 m, with most values in the 10-25 m range. Such small outer scale values cause some components of visibility and astrometric errors to average down rapidly.
Selection for Drought Resistance in Dry Bean Landraces and Cultivars

Drought is a worldwide constraint to dry bean (Phaseolus vulgaris L.) production. The objective of this research was to determine the response of three dry bean landraces and 13 cultivars evaluated under non-stressed (NS) and intermittent drought-stressed (DS) environments at Kimberly, Idaho in 2003 and 2004. The NS received seven irrigations in 2003 and five in 2004, and DS only four in 2003 and two in 2004. Most water use occurred within the top 0.5 m soil in both the NS and DS. Drought reduced biomass and seed yield, harvest index, and seedweight. Maturitywas delayedin severe drought,butwassimilar or shortened by 1 to 6 d under moderate drought. Mean seed yield was reduced by 62% in 2003 and by 27% in 2004. Common Red Mexican and CO 46348 had high seed yield in both NS and DS environments, whereas ‘Matterhorn’ and ‘Othello’ yielded comparatively high under DS but moderately in NS environment. Drought resistance was inadvertently reduced from Common Red Mexican landrace to intermediate levels in ‘NW-63’ and ‘UI 239’ released in 1979 and 1993, respectively, andmore recently released ‘LeBaron’ (1999) and ‘UI 259’ (1996)weresusceptible.Conversely,droughtresistancewasincreasedin newer pinto (Othello 1986; CO 46348) and great northern (Matterhorn 1998) releases compared to the landraces and older cultivars tested for thosemarketclasses.SeedyieldinNSandDSwaspositivelycorrelated. Seed yield was also correlated with harvest index in DS and NS. All early maturing cultivars except Othello (e.g., UI 59, US 1140, Common Pinto, Topaz, UI 320, and LeBaron) were susceptible. Common Red Mexicandidnothaveanyreductioninseedweightduetodroughtstress. Drought resistant genotypes should be used for determining irrigation frequency,amountofwatertobeapplied,andmechanismsofresistance and for identifying, mapping, and pyramiding favorable genes for dryland and irrigation-assisted sustainable production systems.
Distributed network and multiprocessing minicomputer state-of-the-art capabilities

Today's minicomputer and midicomputer state-of-the-art provides two basic types of capabilities for users to evaluate for their applications. The two categories are:• Distributed Networking Systems• Multiprocessing Architectures with High Speed Busses, Shared Main Memory and Shared Disk Systems
A precompiler for the formula manipulation system TRIGMAN

Discussion of a translator designed to simplify the programming of problems involving the TRIGMAN formula manipulation system. The translator allows for the introduction of a new data type, SERIES, into a FORTRAN program and translates a user's program into legal FORTRAN. The translator is adaptable to other formula manipulation systems presently used in celestial mechanics.
A comparison of preoperative and intraoperative evaluations for patients who undergo site-specific operation for the correction of pelvic organ prolapse.

Abstract Objective: We compared preoperative and intraoperative assessments of pelvic organ prolapse to ascertain whether differences existed. Study Design: This study is a retrospective analysis of information that was collected of 193 women who underwent reconstructive operation for pelvic organ prolapse between January 1994 and April 1999 by the senior author (B. L. S.) in this institution. Support for the urethra, bladder, cervix or vaginal cuff, cul-de-sac, and rectum were assessed with the Baden-Walker halfway system before and during the operations. Results: Preoperative and intraoperative assessments were significantly correlated (Spearman rank order correlation, 0.85-0.94). A comparison of the assessments revealed significantly greater prolapse at the urethra, cervix/cuff, cul-de-sac, and rectum on intraoperative evaluation ( P ≤.00007). Conclusion: Intraoperative evaluation of women who are to undergo reconstructive operation for pelvic organ prolapse may reveal greater prolapse at selected sites than previously noted in up to 32% of patients. (Am J Obstet Gynecol 2002;186:1155-9.)
Estradiol improves right ventricular function in rats with severe angioproliferative pulmonary hypertension: effects of endogenous and exogenous sex hormones.

Estrogens are disease modifiers in PAH. Even though female patients exhibit better right ventricular (RV) function than men, estrogen effects on RV function (a major determinant of survival in PAH)...
Nonstationary statistical image models (and their application to image data compression)

Publisher Summary This chapter explores the transformations of a nonstationary image that would yield an image that satisfies the stationary model assumptions. Statistical image models are frequently employed in some current procedures of digital image processing. The models are essentially made implicit by the adoption of assumptions that incorporate certain model assumptions within them. Little has been done in analyzing or processing images on the basis of assumptions other than a stationary process. What has been done has shown that favorable results come from abandoning the stationary process assumption. In almost any situation, the virtue of abandoning the statistically stationary image model can be understood if it is recalled what an image that is truly stationary looks like. The most convenient example of a statistically stationary image is to tune a television set to channel where no station is broadcasting. What is remarkable is that algorithms incorporating the stationary assumption produce usable results.
Exact one-loop thermal free energies of solitons

Abstract I show how to compute the exact one-loop thermal correction to the free energy of a soliton. The method uses the effective potential as an auxiliary step to ensure that the soliton is quantized around the appropriate vacuum. The exact result is then computed using scattering theory techniques, and includes all orders in the derivative expansion. It can be efficiently combined with a calculation of the exact quantum correction to yield the full free energy to one loop. I demonstrate this technique with explicit computations in φ 4 models, obtaining the free energy for a kink in 1+1 dimensions and a domain wall in 2+1 dimensions.
Focusing X-ray monochromator for EXAFS studies in the energy range 4–30 keV☆

Abstract The design and operating principles of a focusing X-ray monochromator are described. Consistent with EXAFS applications, it allows rapid tuning while maintaining high energy resolution and a fixed focus at the sample. The basic instrument consists of two opposing two crystal monochromators with the second and third crystals operating as a dispersive monochromator. This provides the intrinsic resolution of the crystals independent of slit settings or source size effects. Focusing is achieved by a sagittally bent fourth crystal. To maintain a fixed focus, two options are available. In the first, the second crystal pair is translated while the radius of the fourth crystal is held fixed. Thus, the focus remains at the sample, even though the angle of incidence on the bent crystal is changing. In the second option, the radius of the bent crystal is changed dynamically as the scan is carried out. These techniques are compared and a crystal bender designed for rapid tuning is described.
Entropy and Specificity in a Mathematical Theory of Evidence

We review Shafer’s theory of evidence. We then introduce the concepts of entropy and specificity in the framework of Shafer’s theory. These become complementary aspects in the indication of the quality of evidence.
Algorithmic strategies for full waveform inversion: 1D experiments

Full-waveform seismic inversion, i.e., the iterative minimization of the misfit between observed seismic data and synthetic data obtained by a numerical solution of the wave equation provides a systematic, flexible, general mechanism for reconstructing earth models from observed ground motion. However, many difficulties arise for highly resolved models and the associated large-dimensional parameter spaces and high-frequency sources. First, the least-squares data-misfit functional suffers from spurious local minima, which necessitates an accurate initial guess for the smooth background model. Second, total variation regularization methods that are used to resolve sharp interfaces create significant numerical difficulties because of their nonlinearity and near-degeneracy. Third, bound constraints on continuous model parameters present considerable difficulty for commonly used active-set or interior-point methods for inequality constraints because of the infinite-dimensional nature of the parameters. Finally, common gradient-based optimization methods have difficulties scaling to the many model parameters that result when the continuous parameter fields are discretized. We have developed an optimization strategy that incorporates several techniques address these four difficulties, including grid, frequency, and time-window continuation; primal-dual methods for treating bound inequality constraints and total variation regularization; and inexact matrix-free Newton-Krylov optimization. Using this approach, several computations were performed effectively for a 1D setting with synthetic observations.
Phosphine-catalyzed hydration and hydroalkoxylation of activated olefins: use of a strong nucleophile to generate a strong base.

The direct addition of water and a variety of alcohols to activated olefins was observed in the presence of nucleophilic phosphine catalysts. Unlike existing methods, the reactions proceed at room temperature and in the absence of transition metals, or strong acids or bases. The use of simple commercially available catalysts makes this an attractive method for the preparation of β-hydroxy and β-alkoxy substrates, which are prevalent targets and intermediates in organic synthesis. The scope and mechanism of this reaction has been explored, and the compound that acts as the resting state of the catalyst was synthesized independently. Our mechanism also suggests the possibility of extending the scope of this reactivity to other classes of nucleophiles.
Large N gauge theories from orientifolds with NS NS B flux

Abstract We consider D-branes and orientifold planes embedded in non-compact (orbifolded) space-time. We point out that even in the non-compact cases we can turn on non-zero (quantized) NS-NS antisymmetric B-field. In particular, we study the effect of the B-field on four-dimensional large N gauge theories from orientifolds. Thus, in theories with both D3- and D7-branes, the effect of the B-field is non-trivial: the number of D7-branes (of each species) is reduced from 8 (which is the required number if the B-field is trivial) to 4. This results in a different orientifold string theory, and, subsequently, the corresponding large N gauge theory is also different. We explicitly construct large N gauge theories from orientifolds with non-zero B-field backgrounds with N = 2, 1, 0 supersymmetries. These theories, just as their counterparts without the B-field, have the property that in the large N limit computation of any M-point correlation function reduces to the corresponding computation in the parent N = 4 supersymmetric theory with a unitary gauge group.
Negative Regulation of Gq-mediated Pathways in Platelets by G12/13 Pathways through Fyn Kinase

Platelets contain high levels of Src family kinases (SFKs), but their functional role downstream of G protein pathways has not been completely understood. We found that platelet shape change induced by selective G12/13 stimulation was potentiated by SFK inhibitors, which was abolished by intracellular calcium chelation. Platelet aggregation, secretion, and intracellular Ca2+ mobilization mediated by low concentrations of SFLLRN or YFLLRNP were potentiated by SFK inhibitors. However, 2-methylthio-ADP-induced intracellular Ca2+ mobilization and platelet aggregation were not affected by PP2, suggesting the contribution of SFKs downstream of G12/13, but not Gq/Gi, as a negative regulator to platelet activation. Moreover, PP2 potentiated YFLLRNP- and AYPGKF-induced PKC activation, indicating that SFKs downstream of G12/13 regulate platelet responses through the negative regulation of PKC activation as well as calcium response. SFK inhibitors failed to potentiate platelet responses in the presence of Gq-selective inhibitor YM254890 or in Gq-deficient platelets, indicating that SFKs negatively regulate platelet responses through modulation of Gq pathways. Importantly, AYPGKF-induced platelet aggregation and PKC activation were potentiated in Fyn-deficient but not in Lyn-deficient mice compared with wild-type littermates. We conclude that SFKs, especially Fyn, activated downstream of G12/13 negatively regulate platelet responses by inhibiting intracellular calcium mobilization and PKC activation through Gq pathways.
A note on the Marchenko-Pastur law for a class of random matrices with dependent entries

We consider a class of real random matrices with dependent entries and show that the limiting empirical spectral distribution is given by the Marchenko-Pastur law. Additionally, we establish a rate of convergence of the expected empirical spectral distribution.
A Torquoselective Extrusion of Isoxazoline N-Oxides. Application to the Synthesis of Aryl Vinyl and Divinyl Ketones for Nazarov Cyclization

A mild, convenient reaction sequence for the synthesis of Nazarov cyclization substrates is described. The [3+2] dipolar cycloaddition of a nitrone and an electron-deficient alkyne gives an isolable isoxazoline intermediate, which upon oxidation undergoes stereoselective extrusion of nitrosomethane to give aryl vinyl or divinyl ketones.
Analyzing Convergence and Rates of Convergence of Particle Swarm Optimization Algorithms Using Stochastic Approximation Methods

Recently, much progress has been made on particle swarm optimization (PSO). A number of works have been devoted to analyzing the convergence of the underlying algorithms. Nevertheless, in most cases, rather simplified hypotheses are used. For example, it often assumes that the swarm has only one particle. In addition, more often than not, the variables and the points of attraction are assumed to remain constant throughout the optimization process. In reality, such assumptions are often violated. Moreover, there are no rigorous rates of convergence results available to date for the particle swarm, to the best of our knowledge. In this paper, we consider a general form of PSO algorithms, and analyze asymptotic properties of the algorithms using stochastic approximation methods. We introduce four coefficients and rewrite the PSO procedure as a stochastic approximation type iterative algorithm. Then we analyze its convergence using weak convergence method. It is proved that a suitably scaled sequence of swarms converge to the solution of an ordinary differential equation. We also establish certain stability results. Moreover, convergence rates are ascertained by using weak convergence method. A centered and scaled sequence of the estimation errors is shown to have a diffusion limit.
The Mechanism of the Claisen Rearrangement: Déjà Vu All Over Again

The great baseball player Yogi Berra, who is quoted in the title, succinctly described what it meant to learn something that others had long ago appreciated. The mechanism by which the enzyme chorismate mutase accelerates the Claisen rearrangement of chorismic acid has for many years perplexed and intrigued chemists and biochemists. Yet classical effects of solvents and catalysts, which were largely ignored by the chemical community, not only provided important clues about the mechanism of the enzyme, but put the Claisen rearrangement in a new perspective. Whereas chorismic acid once seemed exceptional because it rearranged so rapidly under physiological conditions, it is now clear that even allyl vinyl ether rearranges at room temperature in aqueous solution. While the ability of the enzyme to accelerate the rearrangement of chorismate by a factor of 106 was once considered extraordinary, catalysis by trivalent aluminum compounds matches, and in some cases exceeds, those rate enhancements. Therefore, it really should not be surprising to learn that Nature has independently evolved several structurally distinct solutions to the design of enzyme catalysts for the rearrangement of chorismic acid.
Matching in Networks with Bilateral Contracts

We introduce a model in which firms trade goods via bilateral contracts which specify a buyer, a seller, and the terms of the exchange. This setting subsumes (many-to-many) matching with contracts, as well as supply chain matching. When firms’ relationships do not exhibit a supply chain structure, stable allocations need not exist. By contrast, in the presence of supply chain structure, a natural substitutability condition characterizes the maximal domain of firm preferences for which stable allocations are guaranteed to exist. Furthermore, the classical lattice structure, rural hospitals theorem, and one-sided strategy-proofness results all generalize to this setting. ( C78, D85, D86, L14)
Limited Rationality and the Limits of Supply Reduction

Drug markets have been targeted for increasingly tough enforcement, yet retail prices for cocaine and heroin have fallen by 70–80%. No research has explained adequately why prices have fallen. This paper explores the possibility that part of the explanation may lie in the failure of drug dealers to respond to risks the way the simplest rational actor models might predict.
Overview of the self-sustaining mechanisms of wall turbulence

Abstract This paper reviews the ideas about why wall turbulence is self-sustaining. The paper is to distribute this information to fluid dynamists who are nonspecialists in turbulence. The production of turbulence and Reynolds stress centers on vortices and “streaks” of low speed fluid near the wall. There are two main categories of self-sustaining mechanisms. In one category, parent vortices interact with the wall and produce offspring vortices. In the second category, workers view the mechanisms as instabilities. Streak velocity profiles, profiles where low velocity fluid has accumulated in long streamwise regions of small spanwise extent, are unstable. These regions are caused by streamwise vortices in the near-wall region. The most dangerous perturbation is a sinuous streamwise mode. The mode may be a normal mode or a transient-growth mode. Ultimately the nonlinear development produces a streamwise vortex. In turn, the vortex can reproduce the streak profile. A third category is based on a common mathematical approach. The goal is to construct a low-order dynamical system of differential equations that display the elemental processes of turbulence.
X-ray spectroscopy of cataclysmic variables

Abstract In cataclysmic variables (CVs), accretion onto white dwarfs produces high temperature, high density plasmas. They cool down from kT≈10 keV via bremsstrahlung continuum and K and L shell line emissions. The small volume around white dwarfs means that the plasma densities are much higher than in, e.g., stellar coronae, probably beyond the range well-described by existing models. I will describe potential diagnostics of the temperatures, the densities, and the optical depths of X-ray emitting plasmas in CVs, and present the recent Chandra grating spectra of the magnetic; CV V1223 Sgr as an example.
Fifty Years of Hard-Sphere Bose Gas: 1957-2007

Fifty years ago, Yang and I worked on the dilute hard-sphere Bose gas, which has been experimentally realized only relatively recently. I recount the background of that work, subsequent developments, and fresh understanding. In the original work, we had to rearrange the perturbation series, which was equivalent to the Bogoliubov transformation. A deeper reason for the rearrangement has been a puzzle. I can now explain it as a crossover from ideal gas to interacting gas behavior, a phenonmenon arising from Bose statistics. The crossover region is infinitesimally small for a macroscopic system, and thus unobservable. However, it is experimentally relevant in mesoscopic systems, such as a Bose gas trapped in an external potential, or on an optical lattice.
Structure of Trichosphaerium micrum sp. n.

SYNOPSIS Trichosphaerium micrum sp. n., a marine testate rhizopod, is described. It is ∼ 36 μ in diameter, covered with acicular, hollow, blunt-ended calcite spicules, 1–3 μm in length, that lie flat in a fibrous sheath. The test is penetrated by circular semipermanent apertures through which extend short dactylopodia. Locomotion is by lobopodia which the organism uses to adhere to the substrate. It is multinucleate with an average of 9 nuclei/individual. The type locality is the shallow littoral of Big Pine Key, Florida. Spicules of other species are described and it is suggested that until more is known about the biology of the group, species classification in the order Trichosida be based on spicule structure and orientation, as well as the size of the organism.
Measuring Black Hole Spin Via the X-Ray Continuum-Fitting Method: Beyond the Thermal Dominant State

All prior work on measuring the spins of stellar-mass black holes (BHs) via the X-ray continuum-fitting (CF) method has relied on the use of weakly Comptonized spectra obtained in the thermal dominant (TD) state. Using a self-consistent Comptonization model, we show that one can analyze spectra that exhibit strong power-law components and obtain values of the inner disk radius, and hence spin, that are consistent with those obtained in the TD state. Specifically, we analyze many RXTE spectra of two BH transients, H1743?322 and XTE J1550?564, and we demonstrate that the radius of the inner edge of the accretion disk remains constant to within a few percent as the strength of the Comptonized component increases by an order of magnitude, i.e., as the fraction of the thermal seed photons that are scattered approaches 25%. We conclude that the CF method can be applied to a much wider body of data than previously thought possible, and to sources that have never been observed to enter the TD state (e.g., Cyg X-1).
The Reaction of Organometallic Reagents with Unsymmetrically Substituted Vinamidinium and Chloropropeniminium Salts

Abstract A variety of organometallic reagents have been found to undergo regioselective reaction with 1-aryl-vinamidinium salts and 3-aryl-3-chloropropeniminium salts. The products of such reactions were found to be α,β-unsaturated ketones and chlorovinyl amines, respectively.