cssi/SciSciGPT-SciSciNet huggingface dataset:
Gravitational microlensing with the space interferometry mission

The Space Interferometry Mission (SIM), with its launch date planned for 2005, has as its goal astrometry with ~1 μas accuracy for stars as faint as 20 mag. If the SIM lives up to expectations, it can be used to measure astrometric displacements in the light centroid caused by gravitational microlensing in the events detected photometrically from the ground. The effect is typically ~0.1 mas, i.e., 2 orders of magnitude larger than planned for SIM's accuracy. Therefore, it will be possible to determine the mass, the distance, and the proper motion of almost any MACHO capable of inducing a photometric microlensing event toward the Galactic bulge or the Magellanic Clouds, even though no light from the MACHO has to be detected. For strong microlensing events in which the source is photometrically resolved, like the recent MACHO 95-30 event, SIM's astrometry combined with accurate ground-based photometry will allow the determination of the angular stellar radii, and therefore the effective temperature of the source. The effective astrometric cross sections for gravitational lensing by nearby high proper-motion stars and brown dwarfs are ~(1'')2, and the effective timescales are ~1 yr. SIM will provide the only practical way to measure masses of single nearby objects with ~1% accuracy. The times of lensing events can be predicted years in advance.
Infinitesimal presentations of the Torelli groups

This is a significant revision of the early version of this paper which was posted last December. The speculative section has been removed in light of some recent results of Morita and Kawazumi. Numerous typos have been fixed. The companion paper "The Hodge de Rham Theory of Relative Malcev Completion" has just been posted.
An Overhaul of Fed Doctrine: Nominal Income and the Great Moderation

The Great Moderation is often characterized by the decline in the variability of output and inflation from earlier periods. While a multitude of explanations for the Great Moderation exist, notable research has focused on the role of monetary policy. Specifically, early evidence suggested that the increased stability has been associated with monetary policy that responded much more strongly to rising inflation. Recent evidence casts doubt on this change in monetary policy. An alternative hypothesis is that the change in monetary policy was the result of a change in doctrine; specifically the rejection of the view that inflation was largely a cost-push phenomenon. As a result, this alternative hypothesis suggests that the change in monetary policy beginning in 1979 is reflected in the Federal Reserve's response to movements in nominal income rather than inflation as previously argued. I provide evidence for this hypothesis by estimating the parameters of a monetary policy rule in which policy adjusts to forecasts of nominal GDP for the pre- and post-Volcker eras. Finally, I embed the rule in two dynamic stochastic general equilibrium models with gradual price adjustment to determine whether the overhaul of doctrine can explain the reduction in the volatility of inflation and the output gap.
How Large is the Stock Component of Human Capital

Abstract This paper examines the value of an individual's human capital and the associated return on human capital using U.S. data on male earnings and financial asset returns. We measure the size of the stock component of human capital and assess the implications for life-cycle portfolio decisions. We find that (1) the value of human capital is far below the value implied by discounting earnings at the risk-free rate and (2) the stock component of the value of human capital is smaller than the bond component at all ages and typically averages less than 35 percent of the value of human capital. Data properties that increase the stock component of the value of human capital also act to lower the stock share held in financial wealth.
Evolution of the Chandra CCD spectra of SNR 1987A: probing the reflected-shock picture

We continue to explore the validity of the reflected-shock structure (RSS) picture in SNR 1987A that was proposed in our previous analyses of the X-ray emission from this object. We used an improved version of our RSS model in a global analysis of 14 CCD spectra from the monitoring program with Chandra. In the framework of the RSS picture, we are able to match both the expansion velocity curve deduced from the analysis of the X-ray images and light curve. Using a simplified analysis, we also show that the X-rays and the non-thermal radio emission may originate from the same shock structure (the blast wave). We believe that using the RSS model in the analysis of grating data from the Chandra monitoring program of SNR 1987A that cover a long enough time interval will allow us to build a more realistic physical picture and model of SNR 1987A.
ISO Observations of Quasars and Quasar Hosts

The Infrared Space Observatory (ISO), launched in November 1995, allows us to measure the far-infrared (far-IR) emission of quasars in greater detail and over a wider energy range than previously possible. In this paper, preliminary results in a study of the 5–200 μm continuum of quasars and active galaxies are presented. Comparison of the spectral energy distributions show that, if the far-IR emission from quasars is thermal emission from galaxian dust, the host galaxies of quasars must contain dust in quantities comparable to IR luminous galaxies rather than normal spiral galaxies. In the near-IR, the ISO data confirm an excess due to a warm ‘AGN-related’ dust component, possibly from the putative molecular torus. We report detection of the high-redshift quasar, 1202-0727, in the near-IR indicating that it is unusually IR-bright compared with low-redshift quasars.
Streaming Tree Transducers

The theory of tree transducers provides a foundation for understanding expressiveness and complexity of analysis problems for specification languages for transforming hierarchically structured data such as XML documents. We introduce streaming tree transducers as an analyzable, executable, and expressive model for transforming unranked ordered trees (and forests) in a single pass. Given a linear encoding of the input tree, the transducer makes a single left-to-right pass through the input, and computes the output in linear time using a finite-state control, a visibly pushdown stack, and a finite number of variables that store output chunks that can be combined using the operations of string-concatenation and tree-insertion. We prove that the expressiveness of the model coincides with transductions definable using monadic second-order logic (MSO). Existing models of tree transducers either cannot implement all MSO-definable transformations, or require regular look-ahead that prohibits single-pass implementation. We show a variety of analysis problems such as type-checking and checking functional equivalence are decidable for our model.
Cyclophanes containing large polycyclic aromatic hydrocarbons

Cyclophanes have been firmly entrenched as a distinct class of compounds for well over half a century. The two main factors that have kept this field of chemistry going so strongly for such a long time are tremendous structural diversity and the interesting behaviour that is often observed. Although a very large number cyclophanes has been reported, only a very small proportion of them contain polycyclic aromatic systems that can be thought of as “large”, i.e. with ≥4 rings. This Review puts the spotlight on such cyclophanes, illuminating both the chemistry that was used to synthesize them and what was learned from studying them. Context for the main body is provided by the careful consideration of the anatomy of a cyclophane and the classification of general synthetic approaches. The subsequent sections cover eleven different PAHs and are organized primarily according to increasing size of the aromatic system, starting with pyrene (C16, the only large polycyclic aromatic system to have been incorporated into numerous cyclophanes) and ending with hexabenzo[bc,ef,hi,kl,no,qr]coronene (C42).
Using Worker Quality Scores to Improve Stopping Rules

We consider the crowdsourcing task of learning the answer to simple multiple-choice microtasks. In order to provide statistically significant results, one often needs to ask multiple workers to answer the same microtask. A stopping rule is an algorithm that for a given microtask decides for any given set of worker answers if the system should stop and output an answer or iterate and ask one more worker. A quality score for a worker is a score that reflects the historic performance of that worker. In this paper we investigate how to devise better stopping rules given such quality scores. We conduct a data analysis on a large-scale industrial crowdsourcing platform, and use the observations from this analysis to design new stopping rules that use the workers’ quality scores in a non-trivial manner. We then conduct a simulation based on a real-world workload, showing that our algorithm performs better than the more naive approaches.
An Empirical Analysis of Electricity Regulation on Technical Change in Texas

To evaluate the impact of regulation on the innovativeness of firms, this studyconsiders the unusual case of electric utilities in the state of Texas. In the currentera of deregulation, the electric utility industry in Texas is unique because itsregulation was relatively limited until 1975, after which time Texas legislatorsimposed rate-of-return regulation. Utilizing a translog cost framework on annualdata covering the years 1965 to 1985, this study is thus able to compare the rateof technological change both before and after the imposition of rate-of-returnregulation. The findings indicate that before the implementation of rate-of-returnregulation, costs decreased significantly because of technological progress. Afterthe implementation, however, the findings indicate that costs increased significantlydue to technological regress brought on by regulation.
Robust Benchmark Design

Abstract We model the design of a benchmark fixing as an estimator of fair market value. The fixing data are the transactions of agents whose profits depend on the fixing, implying incentives for manipulation. We derive the optimal linear fixing under an assumption that transaction weights are unidimensional. We also axiomatically characterize the unique linear fixing that is robust to a certain form of collusion among traders. Our analysis provides a foundation for the commonly used volume-weighted average price (VWAP) and its analogue based on unidimensional weights. We characterize the relative advantages of these fixing designs, depending on market characteristics.
The impact of remittances on labor supply : the case of Jamaica

A puzzle in the recently stagnated economy of Jamaica is that high rates of unemployment have persisted even when real wages have been increasing. This paper examines aspects of the labor supply in an effort to understand why high rates of unemployment have existed with increasing real wages. This is a sign of a badly functioning labor market. The cross-sectional analysis suggests that remittances have some impact on labor supply, especially on labor market participation. The pseudo panel data analysis also confirms that remittances have a strong impact on labor participation but not on weekly working hours. Households with remittance income have a higher reservation wage and have reduced the supply of labor by moving out of the labor force.
Direct-Write Photolithography for Cylindrical Tooling Fabrication in Roll-to-Roll Microcontact Printing

The scale-up of microcontact printing (μCP) to a roll-to-roll technique for large-scale surface patterning requires scalable tooling for continuous pattern printing with μm-scale features (e.g., 1–50 μm). Here, we examine the process of creating such a tool using an optical direct-write or “maskless” method working on a rotating cylindrical substrate. A predictive model of pattern formation is presented along with experimental results to examine the key control factors for this process. It is shown that factors can be modulated to vary the cross-sectional shape in addition to feature height and width. This feature can then be exploited to improve the robustness of the final printing process.
Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis.

Objectives Treatment guidelines for acute pulmonary embolism (PE) recommend risk stratifying patients to assess PE severity, as those at higher risk should be considered for therapy in addition to standard anticoagulation to prevent right ventricular (RV) failure, which can cause hemodynamic collapse. The hypothesis was that 12-lead electrocardiography (ECG) can aid in this determination. The objective of this study was to measure the prognostic value of specific ECG findings (the Daniel score, which includes heart rate > 100 beats/min, presence of the S1Q3T3 pattern, incomplete and complete right bundle branch block [RBBB], and T-wave inversion in leads V1–V4, plus ST elevation in lead aVR and atrial fibrillation suggestive of RV strain from acute pulmonary hypertension), in patients with acute PE. Methods Studies were identified by a structured search of MEDLINE, PubMed, EMBASE, the Cochrane library, Google Scholar, Scopus, and bibliographies in October 2014. Case reports, non-English papers, and those that lacked either patient outcomes or ECG findings were excluded. Papers with evidence of a predefined reference standard for PE and the results of 12-lead ECG, stratified by outcome (hemodynamic collapse, defined as circulatory shock requiring vasopressors or mechanical ventilation, or in hospital or death within 30 days) were included. Papers were assessed for selection and publication bias. The authors also assessed heterogeneity (I2) and calculated the odds ratios (OR) for each ECG sign from the random effects model if I2 > 24% and fixed effects if I2 < 25%. Funnel plots were used to examine for publication bias. Results Forty-five full-length studies of 8,209 patients were analyzed. The most frequent ECG signs found in patients with acute PE were tachycardia (38%), T-wave inversion in lead V1 (38%), and ST elevation in lead aVR (36%). Ten studies with 3,007 patients were included for full analysis. Six ECG findings (heart rate > 100 beats/min, S1Q3T3, complete RBBB, inverted T waves in V1–V4, ST elevation in aVR, and atrial fibrillation) had likelihood and ORs with lower-limit 95% confidence intervals above unity, suggesting them to be significant predictors of hemodynamic collapse and 30-day mortality. OR data showed no evidence of publication bias, but the proportions of patients with hemodynamic collapse or death and S1Q3T3 and RBBB tended to be higher in smaller studies. Patients who were outcome-negative had a significantly lower mean ± SD Daniel score (2.6 ± 1.5) than patients with hemodynamic collapse (5.9 ± 3.9; p = 0.039, ANOVA with Dunnett's post hoc), but not patients with all-cause 30-day mortality (4.9 ± 3.3; p = 0.12). Conclusions This systematic review and meta-analysis revealed 10 studies, including 3,007 patients with acute PE, that demonstrate that six findings of RV strain on 12-lead ECG (heart rate > 100 beats/min, S1Q3T3, complete RBBB, inverted T waves in V1–V4, ST elevation in aVR, and atrial fibrillation) are associated with increased risk of circulatory shock and death.
A preliminary review of influential works in data-driven discovery.

The Gordon and Betty Moore Foundation ran an Investigator Competition as part of its Data-Driven Discovery Initiative in 2014. We received about 1100 applications and each applicant had the opportunity to list up to five influential works in the general field of “Big Data” for scientific discovery. We collected nearly 5000 references and 53 works were cited at least six times. This paper contains our preliminary findings.
A Jump Diffusion Model for Agricultural Commodities with Bayesian Analysis

Stochastic volatility, price jumps, seasonality, and stochastic cost of carry have been included separately, but not collectively, in pricing models of agricultural commodity futures and options. We propose a comprehensive model that incorporates all four features. We employ a special Markov chain Monte Carlo algorithm, new in the agricultural commodity derivatives pricing literature, to estimate the proposed stochastic volatility (SV) and stochastic volatility with jumps (SVJ) models. Overall model fitness tests favor the SVJ model. The in-sample and out-of-sample pricing results for corn, soybeans and wheat generally, with few exceptions, lend support for the SVJ model. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark 34:235–260, 2014
Analysis of Cohesive Microsized Particle Packing Structure Using History-Dependent Contact Models

Granular packing structures of cohesive microsized particles with different sizes and size distributions, including monosized, uniform, and Gaussian distribution, are investigated by using two different history dependent contact models with discrete element method (DEM). The simulation is carried out in the framework of liggghts, which is a DEM simulation package extended based on branch of granular package of widely used open-source code LAMMPS. Contact force caused by translation and rotation, frictional and damping forces due to collision with other particles or container boundaries, cohesive force, van der Waals force, and gravity is considered. The radial distribution functions (RDFs), force distributions, porosities, and coordination numbers under cohesive and noncohesive conditions are reported. The results indicate that particle size and size distributions have great influences on the packing density for particle packing under cohesive effect: particles with Gaussian distribution have the lowest packing density, followed by the particles with uniform distribution; the particles with monosized distribution have the highest packing density. It is also found that cohesive effect to the system does not significantly affect the coordination number that mainly depends on the particle size and size distribution. Although the magnitude of net force distribution is different, the results for porosity, coordination number, and mean value of magnitude of net force do not vary significantly between the two contact models.
Optimal decentralized state-feedback control with sparsity and delays

This work presents the solution to a class of decentralized linear quadratic state-feedback control problems, in which the plant and controller must satisfy the same combination of delay and sparsity constraints. Using a novel decomposition of the noise history, the control problem is split into independent subproblems that are solved using dynamic programming. The approach presented herein both unifies and generalizes many existing results.
Development of a six-degree of freedom simulation model for the REMUS autonomous underwater vehicle

Describes the development and verification of a six degree of freedom, non-linear simulation model for the REMUS AUV, the first such model for this platform. In this model, the external forces and moments resulting from hydrostatics, hydrodynamic lift and drag, added mass, and the control inputs of the vehicle propeller and fins are all defined in terms of vehicle coefficients. The paper briefly describes the derivation of these coefficients. The equations determining the coefficients, as well as those describing the vehicle rigid-body dynamics, are left in non-linear form to better simulate the inherently non-linear behavior of the vehicle. Simulation of the vehicle motion is achieved through numeric integration of the equations of motion. The simulator output is then verified against vehicle dynamics data collected in experiments performed at sea. The simulator is shown to accurately model the motion of the vehicle. The paper concludes with recommendations for future model validation experiments.
Robust camera location estimation by convex programming

3D structure recovery from a collection of 2D images requires the estimation of the camera locations and orientations, i.e. the camera motion. For large, irregular collections of images, existing methods for the location estimation part, which can be formulated as the inverse problem of estimating n locations t 1 , t 2 , …, tn in ℝ 3 from noisy measurements of a subset of the pairwise directions t i −t j /∥t i −t j ∥, are sensitive to outliers in direction measurements. In this paper, we firstly provide a complete characterization of well-posed instances of the location estimation problem, by presenting its relation to the existing theory of parallel rigidity. For robust estimation of camera locations, we introduce a two-step approach, comprised of a pairwise direction estimation method robust to outliers in point correspondences between image pairs, and a convex program to maintain robustness to outlier directions. In the presence of partially corrupted measurements, we empirically demonstrate that our convex formulation can even recover the locations exactly. Lastly, we demonstrate the utility of our formulations through experiments on Internet photo collections.
Extremizing Feedback Control of a High-Speed and High Reynolds Number Jet

We present results of the development and application of extremizing feedback control to high-speed and high Reynolds number axisymmetric jets. In particular, we demonstrate control authority on the near-field pressure of a Mach 0.9 jet with a Reynolds number based on jet diameter of 7.8 ◊ 10 5 . Open-loop forcing experiments are presented wherein localized arc filament plasma actuators are shown to have two distinct effects on the near-field pressure, similar to their effect on the far-field acoustics reported earlier. At low forcing Strouhal numbers (StDF’s) near the jet column mode instability, a large amplification in the pressure fluctuations is observed. At higher StDF’s (close to the initial shear layer instability) a broad attenuation is observed in the near-field pressure fluctuations, especially in the axisymmetric mode. Previous experiments have shown that forcing the jet with these low and high frequencies result in jet mixing enhancement and far-field noise reduction, respectively. Two different gradient-free extremizing feedback control algorithms have been implemented, each of which can perform online minimum-seeking as well as maximumseeking. Both methods demonstrate fast convergence to the optimum followed by steady operation.
THE FIRST GALAXIES: ASSEMBLY OF DISKS AND PROSPECTS FOR DIRECT DETECTION

The James Webb Space Telescope (JWST) will enable observations of galaxies at redshifts z {approx}> 10 and hence allow us to test our current understanding of structure formation at very early times. Previous work has shown that the very first galaxies inside halos with virial temperatures T{sub vir} {approx} 10 are probably too faint, by at least one order of magnitude, to be detected even in deep exposures with JWST. The light collected with JWST may therefore be dominated by radiation from galaxies inside 10 times more massive halos. We use cosmological zoomed smoothed particle hydrodynamics simulations to investigate the assembly of such galaxies and assess their observability with JWST. We compare two simulations that are identical except for the inclusion of non-equilibrium H/D chemistry and radiative cooling by molecular hydrogen. In both simulations a large fraction of the halo gas settles in two nested, extended gas disks which surround a compact massive gas core. The presence of molecular hydrogen allows the disk gas to reach low temperatures and to develop marked spiral structure but does not qualitatively change its stability against fragmentation. We post-processmore » the simulated galaxies by combining idealized models for star formation with stellar population synthesis models to estimate the luminosities in nebular recombination lines as well as in the ultraviolet continuum. We demonstrate that JWST will be able to constrain the nature of the stellar populations in galaxies such as simulated here based on the detection of the He1640 recombination line. Extrapolation of our results to halos with masses both lower and higher than those simulated shows that JWST may find up to a thousand star-bursting galaxies in future deep exposures of the z {approx}> 10 universe.« less
Analysis of printed transmission lines for monolithic integrated circuits

Planar transmission lines formed with MIS and Schottky barrier contacts are analysed based on the spectral domain technique. Depending on the frequency and the resistivity of the substrates, three different types of fundamental modes are predicted. The calculated slow-wave factors and attenuation constants agree well with experimental results.
Orthogonal Square Root Eigenfactor Parameterization of Mass Matrices

An improved method is presented to parameterize a smoothly time varying, symmetric, positive dee nite system mass matrix M(t) in terms of the instantaneous eigenfactors, namely, the eigenvalues and eigenvectors of M(t). Differential equations are desired whose solutions generate the instantaneous spectral decomposition of M(t). The derivationmakesuseofthefactthattheeigenvectormatrixisorthogonaland,thus,evolvesanalogously to ahigherdimensional rotation matrix. Careful attention is given to cases where some eigenvalues and/or their derivatives are equal or near equal. A robust method is presented to approximate the corresponding eigenvector derivatives in these cases, which ensures that the resulting eigenvectors still diagonalize the instantaneous M(t) matrix. This method is also capable of handling the rare case of discontinuous eigenvectors, which may only occur if both the corresponding eigenvalues and their derivatives are equal. I. Introduction M OST multibody dynamical systems such as multilink robots have cone guration-dependent mass matrices. This dependency makes the mass matrix vary with time. Solving such dynamical systems involves performing an inverse of the system mass matrix at each integration step. Finding this inverse is computationally dife cult and expensive for large systems. Furthermore, standard inverse and linear equations solution techniques are not easily parallelizable and, therefore, cannot take full advantage of modern parallel computing systems. Amethodisintroducedthatparameterizesthesymmetric,positive dee nite mass matrix in terms of its eigenfactors, i.e., eigenvectors and eigenvalues. Instead of forward integrating the original mass matrix differential equation directly, only the eigenfactors themselves are forward integrated. The resulting formulation is one that could be easily implemented on a massively parallel computer system. A paper by Oshman and Bar-Itzhack 1 introduces an important orthogonal square root eigenfactor parameterization to solve the differential matrix Riccati equation. However, some details of their treatmentofequalornear-equaleigenvalues werefoundtobeincorrect, and the case of discontinuous eigenvectors was not accounted for. This paper provides an approximate treatment of the near-equal eigenvalue case and an associated error analysis where the symmetric,positive dee nite matrix parameterized is a state-dependent mass matrix M.x;t/. Eigenfactor derivatives have been discussed in the literature for quite some time, but they are mostly used to establish modal sensitivities and not to derive eigenfactor differential equations. 2;3 A majority of the engineering literature on eigenfactor derivatives is for the general structural eigenvalue problem .K i ¸iM/vi D 0. This paper deals with the problem where we need to e nd the eigenfactors and their derivatives for given continuous matrices M.x;t/ and P M.x; P
Data Streams: Algorithms and Applications

1 Introduction 2 Map 3 The Data Stream Phenomenon 4 Data Streaming: Formal Aspects 5 Foundations: Basic Mathematical Ideas 6 Foundations: Basic Algorithmic Techniques 7 Foundations: Summary 8 Streaming Systems 9 New Directions 10 Historic Notes 11 Concluding Remarks Acknowledgements References.
Mathematical modeling of drug delivery from autocatalytically degradable PLGA microspheres--a review

PLGA microspheres are widely studied for controlled release drug delivery applications, and many models have been proposed to describe PLGA degradation and erosion and drug release from the bulk polymer. Autocatalysis is known to have a complex role in the dynamics of PLGA erosion and drug transport and can lead to size-dependent heterogeneities in otherwise uniformly bulk-eroding polymer microspheres. The aim of this review is to highlight mechanistic, mathematical models for drug release from PLGA microspheres that specifically address interactions between phenomena generally attributed to autocatalytic hydrolysis and mass transfer limitation effects. Predictions of drug release profiles by mechanistic models are useful for understanding mechanisms and designing drug release particles.
Vortices in the Co-orbital Region of an Embedded Protoplanet

We present global two-dimensional inviscid disk simulations with an embedded planet, emphasizing the nonlinear dynamics in its co-orbital region. We find that the potential vorticity of the flow in this region is not conserved because of the presence of two spiral shocks produced by the planet. As the system evolves, the potential vorticity profile develops extrema (inflection points) that eventually render the flow unstable. Vortices are produced in association with the potential vorticity minima. Born in the separatrix region, these vortices experience close encounters with the planet, consequently exerting strong torques on the planet. The existence of these vortices have important implications for understanding the migration rates of low-mass planets.
Partial median sternotomy: an attractive approach to mediastinal parathyroid disease.

Background Parathyroid exploration through a standard cervical approach is adequate for the resection of most mediastinal parathyroid glands. A subset of mediastinal parathyroid glands causing hyperparathyroidism, however, cannot be removed in this manner.
Best Conventional Solutions to the King’s Problem

In the King's Problem, a physicist is asked to prepare a d-state quantum system in any state of her choosing and give it to a king who measures one of (d + 1) sets of mutually unbiased observables on it. The physicist is then allowed to make a control measurement on the system, following which the king reveals which set of observables he measured and challenges the physicist to predict correctly all the eigenvalues he found. This paper obtains an upper bound on the physicist's probability of success at this task if she is allowed to make measurements only on the system itself (the "conventional" solution) and not on the system as well as any ancillary systems it may have been coupled to in the preparation phase, as in the perfect solutions proposed recently. An optimal conventional solution, with a success probability of 0.7, is constructed in d = 4; this is to be contrasted with the success probability of 0.902 for the optimal conventional solution in d = 2. The gap between the best conventional solution and the perfect solution grows quite rapidly with increasing d.
Detection of a CP-42 cyclotron unique black “burn” pattern

Abstract A unique black “burn” pattern was observed at the outer perimeter of the cyclotron accelerator vacuum chamber. The cause of this black “burn” pattern is attributed to Lorentz stripping of the accelerated H − beam, which then bombards the vacuum chamber walls. This finding provides an explanation for the failure of the CP-42 rf dee insulators. These dee insulators are bombarded by the neutral beam current. This understanding led to corrective action that resulted in reduced cyclotron operating downtime.
Diphoton background to Higgs boson production at the LHC with soft gluon effects

Abstract The detection and the measurement of the production cross section of a light Higgs boson at the CERN Large Hadron Collider demand the accurate prediction of the background distributions of photon pairs. To improve this theoretical prediction, we present the soft-gluon resummed calculation of the pp → γγX cross section, including the exact one loop gg → γγg contribution. By incorporating the known fixed order results and the leading terms in the higher order corrections, the resummed cross section provides a reliable prediction for the inclusive diphoton invariant mass and transverse momentum distributions. Given our results, we propose the search for the Higgs boson in the inclusive diphoton mode with a cut on the transverse momentum of the photon pair, without the requirement of an additional tagged jet.
Fluctuation effects on the physical properties of Cd2Re2O7 near 200 K

Experimental investigation of the resistivity ρ, susceptibility χ, specific heat Cp and Hall coefficient RH of the pyrochlore Cd2Re2O7 reveals the presence of a continuous phase transition of uncertain origin with critical temperature T* = 200 K. Electron and x-ray diffraction measurements indicate that a commensurate structural transformation accompanies the changes in the electronic properties, implying that lattice as well as electronic degrees of freedom are involved in the transition. Remarkable scaling relationships between ρ, χ and Cp are observed, indicating that fluctuations are crucial in the transition regime. Both spin and ionic density fluctuation scenarios are considered.
Cyanide and Carbon Monoxide Ligand Formation in Hydrogenase Biosynthesis

Carbon monoxide (CO) and cyanide (CN–) can act as potent inhibitors of enzymes necessary for primary biochemical processes, however they also play important roles in biological systems. Well-studied cases include CN– biosynthesis in plants to act as a defense against herbivores and pathogens, CN– biosynthesis in certain species of bacteria to remove excess glycine, and CO biosynthesis by microbes for energy metabolism in the Wood–Ljungdahl pathway. The utilization of CO and CN– as essential metal ligands in biology is even more limited, with the only known examples being at the active sites of hydrogenase enzymes. This class of enzymes catalyzes the reversible oxidation of hydrogen, a reaction that in biology appears to be entirely dependent on the presence of CO and/or CN– ligands. To date, synthetic mimicsof hydrogenase active sites have not reproduced hydrogen production rates observed in some hydrogenases; it is thus of considerable interest to understand how biology has solved the intriguing problem of biosynthesizing efficient hydrogen catalysts. Of the hydrogenase enzymes discussed herein, recent advances in the [FeFe]-hydrogenase family has provided important insights into the synthesis of the CO and CN– ligands for its active site (H-cluster). Biosynthesis of the complex [FeFe]-hydrogenase active site requires only three iron–sulfur cluster-containing maturation proteins, where two act as radical S-adenosylmethionine (AdoMet) enzymes (HydE and HydG) and the other as a GTPase (HydF). In this review, biological CO and CN– genesis mechanisms will be assessed with specific focus on [FeFe]-hydrogenase maturation.
Directional sea spectrum determination using HF Doppler radar techniques

Second-order features in HF radar Doppler spectral data are compared with a theoretical model of the radar spectrum. The model is the corner reflector double-scatter model which employs a more realistic directional sea spectrum model than those used in earlier works. It includes a frequency-dependent angular spreading function and assumes the existence of spectral energy over a full 360\deg arising from an apparent second-order wave-wave interaction. Comparison is made with ground wave data collected at the NRL/NOAA/ITS San Clemente Island HF radar.
Charge, Polarizability, and Photoionization of Single Semiconductor Nanocrystals

The electrostatic properties of individual CdSe nanocrystals are directly measured using electrostatic force microscopy (EFM) in dry air at room temperature. We determine that the static dielectric constant of CdSe nanocrystals with diameters 5 nm is uniform. However, the charge per nanocrystal is nonuniform, with some nanocrystals possessing a positive charge. Furthermore, a small fraction of the nanocrystals exhibit a blinking behavior in their charge. This is entirely unexpected for a dielectric particle with no additional charge carriers. In addition, EFM measurements with simultaneous photoexcitation provide direct evidence of nanocrystal photoionization and increased blinking behavior.
Promoting essential laminations

We show that a co-orientable taut foliation of a closed, orientable, algebraically atoroidal 3-manifold is either the weak stable foliation of an Anosov flow, or else there are a pair of very full genuine laminations transverse to the foliation.
Molecular Ecology of Teleost Fish Hemoglobins Strategies for Adapting to Changing Environments

Animals live in environments where physical chemical and biological parameters are continually changing. If homeostasis is to be maintained animals must adapt. The respiratory complex (and specifically hemoglobins) is perhaps the best system to use to study adaptation to environmental stress because it exists at the organism environment interface. Fish are particularly useful in such studies since they respond directly to such variables as temperature oxygen pH and salinity . Maintenance of respiratory homeostasis is achieved by a host of molecular cellular and physiological mechanisms. The linkage between these molecular interactions the animals and the physicochemical environment. I have termed Molecular Ecology. In the following paper I will consider some of these relationships.
Pseudomoments of the Riemann zeta-function and pseudomagic squares

Abstract We compute integral moments of partial sums of the Riemann zeta function on the critical line and obtain an expression for the leading coefficient as a product of the standard arithmetic factor and a geometric factor. The geometric factor is equal to the volume of the convex polytope of substochastic matrices and is equal to the leading coefficient in the expression for moments of truncated characteristic polynomial of a random unitary matrix.
Calculative trust: Oxymoron or tautology?

The Williamsonian model of trust (Williamson, O. E. [1993]. Calculativeness, trust, and economic organization. The Journal of Law and Economics, 36, 453–486) makes the claim that the term ‘trust’ is regularly misused in social sciences research for behavioural phenomena which are better explained in terms of ‘calculativeness’. This essay explores the inescapably calculative nature of trust, organises the multiplex layers of calculative reciprocities and strategic preferences developed by trust parties and further explains how such individual and collectivised trust expectations and premises are ‘bullet-proofed’ into the self-referential and autopoietic process of the trust exchange. Humans are conditioned to calculatively trust for purposes of (economic) cooperation – a process that crucially requires the masking of calculativeness in their trust exchanges. Trust may therefore be best understood as double-blind calculativeness. Given the carefully shielded (self-)deceptive nature of trust relations – and ...
Boundary manifolds of line arrangements

Abstract. While the boundary 3-manifold of a line arrangement in the complex plane depends only on the incidence correspondence of the line arrangement, the homotopy type of the complement depends on the relative positions of incidences. In this paper we describe the homotopy type of line arrangement complements in terms of an associated plumbed graph. For pseudo-real line arrangements this method provides an explicit description of the homotopy type and fundamental group of the complement in terms of its ordered incidence graph. The method also extends to a larger class of “unknotted” line arrangements.
Systematic improvement of parton showers with effective theory

We carry out a systematic classification and computation of next-to-leading order kinematic power corrections to the fully differential cross section in the parton shower. To do this we devise a map between ingredients in a parton shower and operators in a traditional effective field theory framework using a chain of soft-collinear effective theories. Our approach overcomes several difficulties including avoiding double counting and distinguishing approximations that are coordinate choices from true power corrections. Branching corrections can be classified as hard-scattering, that occur near the top of the shower, and jet-structure, that can occur at any point inside it. Hard-scattering corrections include matrix elements with additional hard partons, as well as power suppressed contributions to the branching for the leading jet. Jet-structure corrections require simultaneous consideration of potential $1\ensuremath{\rightarrow}2$ and $1\ensuremath{\rightarrow}3$ branchings. The interference structure induced by collinear terms with subleading powers remains localized in the shower.
CO dissociation induced by adsorbed oxygen and water on Ir(111)

Although CO does not dissociate on the clean Ir(111) surface, the addition of atomic oxygen induces COdissociation at low temperatures (lower than 400 K); similarly, COdissociation has also been observed on water co-adsorbed Ir(111) or water and oxygen co-adsorbed Ir(111).
White holes and eternal black holes

We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi-thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal.
γ-Lactonizations of 2H-chromenes via cyclopropanation

Abstract A two-step synthesis of tetrahydro-2H-furochromenones from 2H-chromenes is reported. The reaction of a series of tert-butyl 2-diazoacetate derivatives with 2H-chromenes, catalyzed by Rh2(OAc)4, generated cyclopropane intermediates that rearranged to γ-lactones on treatment with Sn(OTf)2.
TBAF-Mediated Aldol Reaction of β-Allenoates: Regio- and Stereoselective Synthesis of (2E,4E)-4-Carbinol Alkadienoates

The aldol reaction of β-allenoate with use of a commercial THF solution of tetrabutylammonium fluoride (TBAF) yielded polyfunctionalized (2E,4E)-4-carbinol alkadienoate—a valuable building block—in highly regio- and stereoselective fashion.
Measurements of the Continuum and Atomic Line Radiation from High-Temperature Air

Radiation sources from high temperature equilibrium air noting measurements, equipment and results
Substructure and the halo model of large-scale structure

We develop the formalism to include substructure in the halo model of clustering. Real haloes are not likely to be perfectly smooth, but have substructure which has, to date, been neglected in the halo model - our formalism allows one to estimate the effects of this substructure on measures of clustering. We derive expressions for the two-point correlation function, the power-spectrum, the cross-correlation between galaxies and mass, as well as higher order clustering measures. Simple forms of the formulae are obtained for the limit in which the size of the substructure and the mass fraction in it is small. Inclusion of substructure allows for a more accurate analysis of the statistical effects of gravitational lensing. It may also bring the halo model predictions into better agreement with the small-scale structure seen in recent high-resolution simulations of hierarchical clustering.
Simulation of Supersonic Reacting Hydrocarbon Flows with Detailed Chemistry

This paper presents a parallel multigrid method for computing inviscid and viscous high speed steadystate flows with reacting hydrocarbons. The governing equations for reactive flow are solved using an explicit multigrid algorithm while treating the chemical source terms in a point implicit manner. The CUSP (Convective Upwind and Split Pressure) scheme is used to provide necessary artificial dissipation without contaminating the solution. This explicit method yields excellent parallel speedups, thus enabling the calculation of reactive flows with detailed chemical kinetics including large numbers of species and reactions. Results indicate good multigrid speedups and adequate resolution of the reaction zone in inviscid and viscous two-dimensional hydrogen/air and methane/air test cases.
Approaches to selective isoprenologation via reactions of (η3-allyl)Fe(CO)+4 with allyl nucleophiles

Abstract The reactions of substituted (η 3 -allyl)Fe(CO) 4 BF 4 complexes 1 with various allyl-metals [M = SiMe 3 ( 2 ), -SnBu 3 ( 3 ) and -FeCp(CO) 2 ( 4 )] and dienolate derivatives [CH 2 C(CH 3 )CH COM(OR) (M = Li, SiMe 3 )] have been investigated in search of a method for regio- and stereocontrolled allyl-allyl coupling. All three classes of allyl derivatives react with 1 in moderate to good yield with variable regioselectivity; the silyl derivatives 2 generally provide good regioselectivity for attack at the less substituted terminus of unsymmetrical derivatives of 1 but deprotonation of the 1,1-dimethylallyl complex 1e prevents efficient isoprenylation. Although deprotonation of 1e also dominates with the siloxydienes, the lithium dienolates couple efficiently with 1 ; however, reaction at the α position of the dienolate dominates.
Efficient online learning for opportunistic spectrum access

The problem of opportunistic spectrum access in cognitive radio networks has been recently formulated as a non-Bayesian restless multi-armed bandit problem. In this problem, there are N arms (corresponding to channels) and one player (corresponding to a secondary user). The state of each arm evolves as a finite-state Markov chain with unknown parameters. At each time slot, the player can select K &#60; N arms to play and receives state-dependent rewards (corresponding to the throughput obtained given the activity of primary users). The objective is to maximize the expected total rewards (i.e., total throughput) obtained over multiple plays. The performance of an algorithm for such a multi-armed bandit problem is measured in terms of regret, defined as the difference in expected reward compared to a model-aware genie who always plays the best K arms. In this paper, we propose a new continuous exploration and exploitation (CEE) algorithm for this problem. When no information is available about the dynamics of the arms, CEE is the first algorithm to guarantee near-logarithmic regret uniformly over time. When some bounds corresponding to the stationary state distributions and the state-dependent rewards are known, we show that CEE can be easily modified to achieve logarithmic regret over time. In contrast, prior algorithms require additional information concerning bounds on the second eigenvalues of the transition matrices in order to guarantee logarithmic regret. Finally, we show through numerical simulations that CEE is more efficient than prior algorithms.