cssi/SciSciGPT-SciSciNet huggingface dataset:
A Luminous Spider

ONE day in Central Burma the trail in the jungle was exceptionally difficult. It was long past noon when I realised that the return journey would be equally long and tiring. Camp lay on the other side of a long range of hills, and there was a short cut from the main trail that would save several miles, but this trail was faint. I reached the supposed cut-off about dusk and followed it upward. Darkness came on swiftly, and my pony began to stumble. Somewhere we had missed the trail, for at intervals I could still glimpse the crest of the hills, and I knew my general direction.
HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON THE COSMOLOGICAL DECELERATION-ACCELERATION TRANSITION REDSHIFT

We compile a list of 28 independent measurements of the Hubble parameter between redshifts 0.07 ≤ z ≤ 2.3 and use this to place constraints on model parameters of constant and time-evolving dark energy cosmologies. These H(z) measurements by themselves require a currently accelerating cosmological expansion at about, or better than, 3σ confidence. The mean and standard deviation of the six best-fit model deceleration-acceleration transition redshifts (for the three cosmological models and two Hubble constant priors we consider) are z da = 0.74 ± 0.05, in good agreement with the recent Busca et al. determination of z da = 0.82 ± 0.08 based on 11 H(z) measurements between redshifts 0.2 ≤ z ≤ 2.3, almost entirely from baryon-acoustic-oscillation-like data.
Mitigating timing errors in time-interleaved ADCs: A signal conditioning approach

Novel techniques based on signal-conditioning are presented to mitigate timing errors in time-interleaved ADCs. A theoretical bound on the achievable spurious signal content, on applying the techniques, is also derived. Behavioral simulations corroborating the same are presented.
Coherent anti-stokes Raman scattering in benzene and nitromethane shock-compressed to 10 GPa

Abstract The frequency shifts of the ring-stretching mode of shock-compressed liquid benzene and the CN stretching mode of nitromethane have been measured using coherent anti-Stokes Raman scattering. Shock pressures up to 11 GPa were achieved using a two-stage light gas gun. The frequency shifted Raman signal was generated using single pulse Nd:YAG and broadband-type lasers.
Multiphoton ionization of azulene and naphthalene

Molecular beams of azulene and naphthalene are irradiated by the output of a tunable pulsed laser and the charged species produced by multiphoton ionization (MPI) are analyzed using a quadrupole mass spectrometer. A study of the ion fragmentation pattern as a function of laser power and laser wavelength permits these two C10H8 isomers to be readily distinguished. Compared to electron impact (EI) ionization, the MPI process can produce more gentle ionization at low laser powers and more extensive fragmentation at high laser powers. The former permits the study of azulene and naphthalene dimers from which their heats of dissociation are estimated. In the case of azulene, two‐color excitation yields a mass spectrum that differs from the mass spectrum obtained by excitation with either color, alone. The ionization efficiency of MPI is very high, exceeding that of EI during the time the pulsed laser is on. A qualitative description involving autoionizing states is presented to account for this efficiency and t...
Estimating the variance in before-after studies.

Abstract Problem To simplify the computation of the variance in before-after studies, it is generally assumed that the observed crash data for each entity (or observation) are Poisson distributed. Given the characteristics of this distribution, the observed value ( x i ) for each entity is implicitly made equal to its variance. However, the variance should be estimated using the conditional properties of this observed value (defined as a random variable), that is, f ( x i | μ i ), since the mean of the observed value is in fact unknown. Method Parametric and non-parametric bootstrap methods were investigated to evaluate the conditional assumption using simulated and observed data. Results The results of this study show that observed data should not be used as a substitute for the variance, even if the entities are assumed to be Poisson distributed. Consequently, the estimated variance for the parameters under study in traditional before-after studies is likely to be underestimated. Conclusions The proposed methods offer more accurate approaches for estimating the variance in before-after studies.
Recursive sparse recovery in large but structured noise — Part 2

We study the problem of recursively recovering a time sequence of sparse vectors, St, from measurements Mt := St + Lt that are corrupted by structured noise Lt which is dense and can have large magnitude. The structure that we require is that Lt should lie in a low dimensional subspace that is either fixed or changes “slowly enough” and the eigenvalues of its covariance matrix are “clustered”. We do not assume any model on the sequence of sparse vectors. Their support sets and their nonzero element values may be either independent or correlated over time (usually in many applications they are correlated). The only thing required is that there be some support change every so often. We introduce a novel solution approach called Recursive Projected Compressive Sensing with cluster-PCA (ReProCS-cPCA) that addresses some of the limitations of earlier work. Under mild assumptions, we show that, with high probability, ReProCS-cPCA can exactly recover the support set of St at all times; and the reconstruction errors of both St and Lt are upper bounded by a time-invariant and small value.
The demand-side dynamics of entrant heterogeneity

Differences in demand conditions between the early and later parts of the demand-growth stage of an industry’s life-cycle generate three sets of hypotheses about industry entrants. These differences in demand conditions explain why later industry entrants differ in their vertical scope, in their product offerings, and in their geographic scope. The hypotheses are tested in the context of the post-divestiture US Long Distance Telecommunications Services industry during 1984–1996. The tests control for firm-specific explanations of industry entrants’ characteristics and the results are consistent with the main hypotheses.
Jones–Witten Invariants for Nonsimply Connected Lie Groups and the Geometry of the Weyl Alcove

Abstract The quotient process of Muger and Bruguieres is used to construct modular categories and TQFTs out of closed subsets of the Weyl alcove of a simple Lie algebra. In particular it is determined at which levels closed subsets associated to nonsimply connected groups lead to TQFTs. Many of these TQFTs are shown to decompose into a tensor product of TQFTs coming from smaller subsets. The “prime” subsets among these are classified, and apart from some giving TQFTs depending on homology as described by Murakami, Ohtsuki and Okada, they are shown to be in one-to-one correspondence with the TQFTs predicted by Dijkgraaf and Witten to be associated to Chern–Simons theory with a nonsimply connected Lie group. Thus in particular a rigorous construction of the Dijkgraaf–Witten TQFTs is given. As a byproduct, a purely quantum groups proof of the modularity of the full Weyl alcove for arbitrary quantum groups at arbitrary levels is given.
Computer Simulation and Design of the Control System for a Wind Turbine Generator

This project is a part of an overall study aimed at producing a new generation of wind turbine generators. The wind turbine generator proposed is a horizontal axis machine with three blades operating downwind. A hydraulic system actuates mechanical linkages to control blade pitch during operation. The blade pitch control concept provides active control of rotor rpm above the rated wind speed and during no load condition. The lowering of blade and tower loads while providing the capability for well tuned rotor control are its primary features. A hydraulic system, designed to control the pitch of the blades of a wind turbine generator, is simulated on the digital computer using the Runge-Kutta method. The control system subroutine is coupled with the aerodynamic subroutines of the blades to represent the model for the wind turbine generator. The response of the simulated wind turbine to a real wind case is shown to agree with the desired response.
CATALYST DISPERSION ON SUPPORTED ULTRAMICROPOROUS INORGANIC MEMBRANES USING DERIVATIZED SILYLATION AGENTS

Two approaches were utilized to disperse rhodium metal particles onto the ultramicroporous silica separation layer of a composite inorganic membrane prepared by modification of a commercial alumina support. In one approach, the silica membrane surface was first amine-derivatized using the silylation agent H2N (CH2)2 NH (CH2)3 Si (OCH3)3, followed by reaction with the metal-organic compound [(1,5-COD) RhCl]2. This approach led to uniformly dispersed ca. 6 nm rhodium particles located only on the surface of the membrane (as revealed by cross-sectional transmission electron microscopy) after a hydrogen reduction at 200°C. The size of the [(1,5-COD) RhCl]2 molecule combined with a reduction of the pore size due to silylation apparently prevented significant penetration into the membrane separation layer. Modest reductions (ca. 50%) in helium and nitrogen permeability resulted from this treatment. An alternative procedure involved wet impregnation of the membrane with a (Rh(acac)3)/THF solution, followed by air calcination and hydrogen reduction. This approach produced a much lower coverage of ca. 4 nm rhodium particles. Helium and nitrogen permeability measurements indicated that considerable pore blockage existed after the calcination step, and that the reduction step led to defect or crack formation in the SiO2 membrane layer as evidenced by a sizeable increase in permeability. It was proposed that the silylation approach led to the [(1,5-COD) RhCl]2 precursor being located primarily on the surface with little pore penetration, while the Rh(acac)3 was able to penetrate the pores to a greater extent, leading to damage of the membrane layer during decomposition of the ligands. The silylation approach appears to be a general strategy to control the size, surface coverage, and location of catalyst in catalytic membrane design.
Contrastive Rhetoric: Cross-Cultural Aspects of Second Language Writing

PART 1 PRELIMINARIES: EARLY PHASES OF THE FIELD 1 Toward an extended definition of contrastive rhetoric 2 Contrastive rhetoric studies in applied linguistics 3 Historical evaluation of contrastive rhetoric: from Kaplan's 1966 study to diversification in languages, genres, and authors PART 2 INTERFACES WITH OTHER DISCIPLINES 4 Contrastive rhetoric and the field of rhetoric and composition 5 Contrastive rhetoric and text linguistics 6 Writing as an activity embedded in a culture 7 Contrastive rhetoric and translation studies 8 Genre-specific studies in contrastive rhetoric PART 3 IMPLICATIONS OF CONTRASTIVE RHETORIC 9 Methods of research in contrastive rhetoric 10 Conclusion: Implications and research directions
Cryotronics: problems and promise

In the past few years cryotronic technology has matured to the point where one may reasonably discuss basic limitations and important engineering problems. The basic limitations stem from certain specifics of the technology, such as gain bandwidth products, impedance and signal levels and the required low-temperature environment. The engineering problems are the problems associated with taking a device from the laboratory to the production line. Reliability, electrical and mechanical strengths, quality control, yield rates and other economic problems have, at worst, a certain nuisance value in the laboratory, but are of vital importance in a production situation.
Dyakonov–Tamm waves guided jointly by an ordinary, isotropic, homogeneous, dielectric material and a hyperbolic, dielectric, structurally chiral material

The planar interface of an ordinary, isotropic, homogeneous, dielectric material and a hyperbolic, dielectric, structurally chiral material can support the propagation of one or multiple Dyakonov–Tamm waves, at a specified frequency and along a specified direction in the interface plane. When multiple Dyakonov–Tamm waves can exist, they differ in phase speed, propagation length, degree of localization to the interface, and spatial profiles of the associated electromagnetic fields. Dependence on the relative permittivity scalar of the isotropic partnering material suggests exploitation for optical sensing of analytes in fluids.
Systematic Uncertainties in Black Hole Masses Determined from Single-Epoch Spectra

We explore the nature of systematic errors that can arise in measurement of black hole masses from single-epoch (SE) spectra of active galactic nuclei (AGNs) by utilizing the many epochs available for NGC 5548 and PG1229+204 from reverberation mapping (RM) databases. In particular, we examine systematics due to AGN variability, contamination due to constant spectral components (i.e., narrow lines and host galaxy flux), data quality (i.e., signal-to-noise ratio (S/N)), and blending of spectral features. We investigate the effect that each of these systematics has on the precision and accuracy of SE masses calculated from two commonly used line width measures by comparing these results to recent RM studies. We calculate masses by characterizing the broad H? emission line by both the full width at half maximum and the line dispersion, and demonstrate the importance of removing narrow emission-line components and host starlight. We find that the reliability of line width measurements rapidly decreases for S/N lower than ~ 10-20 (per pixel), and that fitting the line profiles instead of direct measurement of the data does not mitigate this problem but can, in fact, introduce systematic errors. We also conclude that a full spectral decomposition to deblend the AGN and galaxy spectral features is unnecessary, except to judge the contribution of the host galaxy to the luminosity and to deblend any emission lines that may inhibit accurate line width measurements. Finally, we present an error budget which summarizes the minimum observable uncertainties as well as the amount of additional scatter and/or systematic offset that can be expected from the individual sources of error investigated. In particular, we find that the minimum observable uncertainty in SE mass estimates due to variability is 0.1 dex for high S/N (20 pixel?1) spectra.
A two factor theory of schizophrenia

Publisher Summary This chapter discusses an alternative theory to the dopamine theory of schizophrenia that would be a two-factor theory of schizophrenia. The theory proposes that the schizophrenic episode is controlled by some factor other than excess dopaminergic stimulation such as an abnormal molecule like dimethoxydopamine (DMPEA) or the first factor. Dopaminergic stimulation, however, markedly aggravates schizophrenia or the second factor. This first factor represents the turning on of schizophrenia, the second factor, dopaminergic stimulation, turns up the gain. One needs both factors to have an overt schizophrenic episode. Phenothiazines, in blocking dopaminergic stimulation, turn down the gain. This allows the normal reparative processes to occur so that the basic schizophrenic pathology heals, after weeks or months. Conversely, methylphenidate and the amphetamines stimulate schizophrenia by turning up the gain.
Tax Planning and the Exercise of Employee Stock Options

This paper analyzes tax planning by holders of employee stock options and examines their response to a proposed tax rate increase. Consistent with tax planning, the frequency of exercise is greater for employees afiected by the tax change than for (i) employees unlikely to be afiected by the tax increase who contemporaneously held identical options, and (ii) employees with comparable incomes who held similar options in other years. Consistent with a reluctance to act in anticipation of tax law changes, less than one third of the option holders who would beneflt most from exercise for tax reasons chose to exercise early.
Control and stability problems of remote orbital capture

Certain space shuttle missions may require retrieval of passive spinning and precessing satellites. One proposed means of retrieval utilizes a free-flying teleoperator launched from the shuttle. A study of misalignment, stability, and certain control aspects during capture of an object is reported here. The approach used is to model the dynamics by a Lagrangian formulation and apply torque components to dissipate motion. Differential angular rates between teleoperator and object are assumed, and control responses after capture are reviewed.
New model catalysts (platinum nanoparticles) and new techniques (SFG and STM) for studies of reaction intermediates and surface restructuring at high pressures during catalytic reactions

Abstract Single-crystal surfaces have long served us well as model catalysts; however, a new type of model catalyst has been prepared using electron beam lithography. Ordered arrays of platinum nano-particles in the 2.5–50 nm size range are deposited on oxide substrates (silica, alumina, and titania) of 1 cm 2 surface area, and are used in catalyzed surface reactions at high pressures (atmospheres). Their preparation, cleaning, and reactivity is discussed. Scanning tunneling microscopy (STM) and vibrational spectroscopy by sum frequency generation (SFG) can be utilized to monitor the substrate and adsorbate structure, respectively, over a fourteen order of magnitude pressure range (10 −10 –10 4 Torr). As a consequence, we can monitor the surface structure and reaction intermediates during high pressure catalytic reactions. An STM that operates at both high pressure (atmosphere) and high temperature has been constructed and utilized to monitor platinum (111) and (110) surface structure during chemisorption of H 2 , O 2 and CO, and during catalytic reactions of olefin hydrogenation and hydrogenolysis. Changes of surface structure upon chemisorption and during reactions have been monitored. Catalysis by the platinum tip was also detected in the presence of H 2 or O 2 at high pressures and 300 K, leading to hydrogenation or oxidation of carbonaceous deposits with nanometer spatial resolution. Vibrational spectroscopy using SFG has been used to monitor pressure dependent changes in the chemisorption of CO and NO over Pt(111). Bonding — which is similar to that in Pt m (CO) n (where n m > 1 ) clusters and for an incommensurate CO overlayer — is observed above 100 Torr. Reaction intermediates that form during ethylene, propylene, and isobutene hydrogenation, as well as CO oxidation, at atmospheric pressures and 300 K were monitored by SFG. The dominant reacting species that hydrogenate are the weakly π-bonded olefins, while the strongly chemisorbed alkylidyne and di-σ bonded species are spectators during the reaction. From quantitative measurement of coverages, the absolute turnover rates can be determined.
Synthesis of Tc(NO)(PPh3)3(H)2: a novel hydrido complex of technetium

Description of the preparation and characterization of a novel diamagnetic dihydrido complex of technetium(I) containing a nitrosyl trans to a hydrido ligand.
Uniform peak optical conductivity in single-walled carbon nanotubes

Recent Rayleigh scattering measurements show that all single-walled carbon nanotubes have a peak optical conductivity of approximately 8 ${e}^{2}/h$, independent of radius, chiral angle, or whether the nanotube is semiconducting or metallic [D. Y. Joh et al., Nat. Nanotechnol. 6, 51 (2011)]. We show that this uniform peak conductivity is a consequence of the relativistic band structure and strength of the Coulomb interaction in carbon nanotubes. We also show that a simple exciton model accurately describes the general phenomenology and the numerical value of the peak optical conductivity. Our work illustrates the need for careful treatment of relaxation mechanisms in modeling the optoelectronic properties of carbon nanotubes.
Reexamination of over-the-barrier and tunneling ionization of the hydrogen atom in an intense field

Ionization of the hydrogen atom in an intense laser field is calculated using the classical-trajectory Monte Carlo method with allowance of tunneling at the classical turning points. With an initial condition of zero angular momentum, excellent agreement with an accurate quantum-mechanical calculation is obtained. The usually mentioned classical threshold for ionization at field strength ${0.0625e/a}_{0}^{2}$ is shown to be irrelevant to realistic pulses; the effective classical thresholds for an adiabatically ramped dc pulse are found to be ${0.080e/a}_{0}^{2}$ in one dimension and ${0.130e/a}_{0}^{2}$ in three dimensions.
Application of Daugulis Copper-Catalyzed Direct Arylation to the Synthesis of 5-Aryl Benzotriazepines

A method for the direct arylation of benzotriazepines is reported, employing an aryl iodide as the coupling partner, copper iodide as the catalyst, and lithium tert-butoxide as the base. A variety of electron-rich, electron-poor, and sterically hindered aryl iodides are compatible with the reaction conditions. The arylation reaction can also be performed outside a glovebox in air without a significant decrease in yield. Furthermore, convenient microwave conditions for carrying out this transformation are reported.
Matched comparison of radical nephrectomy vs. nephron-sparing surgery in patients with unilateral renal cell carcinoma and a normal contralateral kidney.

Objective: To report the long-term follow-up of a matched comparison of radical nephrectomy (RN) and nephron-sparing surgery (NSS) in patients with single unilateral renal cell carcinoma (RCC) and a normal contralateral kidney. Patients and Methods: Between August 1966 and March 1999, 1492 and 189 patients with unilateral RCC and a normal contralateral kidney underwent RN and NSS, respectively. Patients with renal impairment, previous nephrectomy, bilateral or multiple RCCs, metastasis, and familial cancer syndromes were excluded. A total 164 patients in each cohort were matched according to pathological grade, pathological T stage, size of tumor, age, sex, and year of surgery. The Kaplan-Meier method and stratified Cox proportional hazards model were used to estimate and compare overall, cancer-specific, local recurrence-free, and metastasis-free survival and survival free of chronic renal insufficiency. The 2 groups were evaluated for early (⩽30 days) complications and proteinuria at last follow-up. Results: At last follow-up, 126 RN patients (77%) and 130 NSS patients (79%) were alive with no evidence of disease. There was no significant difference observed between patients who had RN and those who had NSS with respect to overall survival (risk ratio, 0.96; 95% confidence interval [CI], 0.52–1.74; P = .88) or cancer-specific survival (risk ratio, 1.33; 95% CI, 0.30–5.95; P = .71). At 10 years, similar rates of contralateral recurrence (0.9% for RN vs 1% for NSS) and metastasis (4.9% for RN vs 4.3% for NSS) were seen in each group, whereas the rate of ipsilateral local recurrence for patients who underwent RN and NSS was 0.8% and 5.4%, respectively (P = .18). There was no significant difference in the early complications between the RN and NSS groups. However, patients who underwent RN had a significantly higher risk for proteinuria as defined by a protein/osmolality ratio of 0.12 or higher (55.2% vs 34.5%; P = .01). At 10 years, the cumulative incidence of chronic renal insufficiency (creatinine > 2.0 mg/dL at least 30 days after surgery) was 22.4% and 11.6%, respectively, for the RN and NSS groups (risk ratio, 3.7; 95% CI, 1.2–11.2; P = .01). Conclusions: This retrospective study of patients with unilateral RCC and a normal contralateral kidney suggests that NSS is as effective as RN for the treatment of RCC on long-term follow-up. The increased risk of chronic renal insufficiency and proteinuria after RN supports use of NSS.
More superstrings from supergravity

Abstract The four six-dimensional “little string” theories are all described in the infinite momentum frame (IMF) as matrix theories by non-trivial 1 + 1-dimensional infra-red fixed points. We characterize these fixed points using supergravity. Starting from the matrix theory definition of M5-branes, we derive an associated dual supergravity description of the fixed point theories, arising as the near-horizon geometry of certain brane configurations. These supergravity solutions are all smooth, and involve three-dimensional anti-de Sitter space AdS 3 . They therefore provide a complete description of the fixed point theories, and hence the IMF little string theories, if the AdS/CFT correspondence holds.
Observations of circumstellar disks with infrared interferometry

The structure and composition of circumstellar disks around young stars is one of the areas in which infrared interferometry has had a major impact. I will review the observational progress in this field starting from the earliest observations of T Tauri, Herbig Ae/Be and FU Ori objects with smaller interferometers. Highlights of recent work include measurements of the inner disk size across 5 orders of magnitude in stellar luminosity, characterization of the dust composition as a function of radius in Herbig disks, high spectral resolution observations of gas emission and closure phase measurements of structure in disks. These observations have challenged models of disk structure and as the only direct probe on AU scales will continue to provide essential input in our understanding of the formation of stars and planets.
Role of Complement in Porphyrin-induced Photosensitivity

Addition of porphyrins to sera of guinea pigs in vitro, followed by irradiation with 405 nm light, resulted in dose-dependent inhibitions of hemolytic activity of complement (CH50, C3, and C5). With guinea pig as an animal model, we also found that systemically administered porphyrins, followed by irradiation with 405 nm light, resulted in dose-dependent inhibition of CH50 in vivo. The erythrocytes from porphyrin-treated guinea pigs showed an increased susceptibility to hemolysis induced by 405 nm irradiation in vitro. Clinical changes in these animals were limited to light-exposed areas and consisted of erythema, crusting, and delayed growth of hair. Histologically, dermal edema, dilation of blood vessels, and infiltration of mononuclear and polymorphonuclear cells were observed. Guinea pigs irradiated with ultraviolet-B developed erythema, but had no alteration of their complement profiles. It is suggested that complement products may play a specific role in the pathogenesis of the cutaneous lesions of some porphyrias.
On the uniqueness of a circuit's DC operating point when its transistors have variable current gains

The theory regarding the uniqueness of the DC operating point of bipolar transistor circuits is extended to the more general situation where each transistor model's controlled-source current gains are allowed to vary. It is then shown that, in certain cases, a transistor with variable current gain can be modeled at two of its operating points as a transistor with fixed gain combined with nonpassive elements. The topological criteria for unique DC operating points is examined. >
On the pseudolocalized solutions in multi-dimension of Boussinesq equation

A new class of solutions of three-dimensional equations from the Boussinesq paradigm are considered. The corresponding profiles are not localized functions in the sense of the integrability of the square of the solution over an infinite domain. For the new type of solutions, the gradient and the Hessian/Laplacian are square integrable. In the linear limiting case, analytical expressions for the profiles of the pseudolocalized solutions are found. The nonlinear case is treated numerically with a special approximation of the differential operators with spherical symmetry that allows for automatic acknowledgement of the behavioral conditions at the origin of the coordinate system. The asymptotic boundary conditions stem from the 1/? behavior at infinity of the pseudolocalized profile. A special approximation is devised that allows us to obtain the proper behavior with a much smaller computational domain. The pseudolocalized solutions are obtained for both quadratic and cubic nonlinearity.
Rhodium-catalyzed cyclopropanations of allylsilanes and allylstannanes: the role of the silyl/stannyl group in trans–cis stereoselection

Abstract The stereochemistry of cyclopropanation reactions between allylsilanes and allylstannanes 6 with four representative diazoalkanes in the presence of rhodium acetate has been studied. Cyclopropanations with ethyl diazoacetate show a preference for the formation of the trans cyclopropane esters 7 , whereas the corresponding reactions with (trimethylsilyl)diazomethane favor the cis stereoisomers. In both cases, overall stereoselection is low, ranging from 1.3:1 to 2.4:1. The product ratios show a small dependence on the nature of the silyl or stannyl groups, with silyl substituents giving better stereoselection than stannyl, and larger ligands on the metal center leading to lower selectivity. On the other hand, rhodium-catalyzed cyclopropanations using methyl 2-diazo-4-phenyl-3-butenoate or 1-aryldiazoacetates occur with excellent stereocontrol. The stereochemical patterns found in these reactions are in accord with an open transition state model wherein the rhodium carbenoid approaches the allylmetal π-bond from an antiperiplanar orientation with respect to the allylic carbonML 3 bond. While the metal center may help stabilize developing β-cationic charge in the transition states, hyperconjugation effects appear to play a minor role, if any, in directing the stereochemical course of cyclopropanation.
A Conversation with Chris Heyde

Born in Sydney, Australia, on April 20, 1939, Chris Heyde shifted his interest from sport to mathematics thanks to inspiration from a schoolteacher. After earning an M.Sc. degree from the University of Sydney and a Ph.D. from the Australian National University (ANU), he began his academic career in the United States at Michigan State University, and then in the United Kingdom at the University of Sheffield and the University of Manchester. In 1968, Chris moved back to Australia to teach at ANU until 1975, when he joined CSIRO, where he was Acting Chief of the Division of Mathematics and Statistics. From 1983 to 1986, he was a Professor and Chairman of the Department of Statistics at the University of Melbourne. Chris then returned to ANU to become the Head of the Statistics Department, and later the Foundation Dean of the School of Mathematical Sciences (now the Mathematical Sciences Institute). Since 1993, he has also spent one semester each year teaching at the Department of Statistics, Columbia University, and has been the director of the Center for Applied Probability at Columbia University since its creation in 1993. Chris has been honored worldwide for his contributions in probability, statistics and the history of statistics. He is a Fellow of the International Statistical Institute and the Institute of Mathematical Statistics, and he is one of three people to be a member of both the Australian Academy of Science and the Australian Academy of Social Sciences. In 2003, he received the Order of Australia from the Australian government. He has been awarded the Pitman Medal and the Hannan Medal. Chris was conferred a D.Sc. honoris causa by University of Sydney in 1998. Chris has been very active in serving the statistical community, including as the Vice President of the International Statistical Institute, President of the Bernoulli Society and Vice President of the Australian Mathematical Society. He has served on numerous editorial boards, most notably as Editor of Stochastic Processes and Their Applications from 1983 to 1989, and as Editor-in-Chief of Journal of Applied Probability and Advances in Applied Probability since 1990. His research has spanned almost all areas of probability and statistics, ranging from random walks to branching processes, from martingales to quasi-likelihood inference, from genetics to option pricing, from queueing theory to long-range dependence. He has edited twelve books, and authored or co-authored three books, I. J. Bienayme: Statistical Theory Anticipated (1977), with E. Seneta, Martingale Limit Theory and Its Application (1980), with P. Hall, and Quasi-Likelihood and Its Applications (1977). Chris Heyde has been an outstanding citizen and leader of the probability and statistics research community. The interview ranges over his education in Australia, moves to the USA and the UK, return to Australia, appointment at Columbia, major research contributions, and professional society and editorial activities. It ends with a look forward in time and some concerned comments about the future for statistics departments.
Anomalous electromagnetic microwave absorption of superconducting alloys in a static magnetic field.

Abstract The microwave surface-resistance anomaly of impure superconducting Al in a static magnetic field is qualitatively explained. It is also discussed how surface-superconductivity affects the surface-resistance.
Minimizing the Flow Time Without Migration

We consider the classical problem of scheduling jobs in a multiprocessor setting in order to minimize the flow time (total time in the system). The performance of the algorithm, both in offline and online settings, can be significantly improved if we allow preemption, i.e., interrupt a job and later continue its execution, perhaps migrating it to a different machine. Preemption is inherent to make a scheduling algorithm efficient. While in the case of a single processor most operating systems can easily handle preemptions, migrating a job to a different machine results in a huge overhead. Thus, it is not commonly used in most multiprocessor operating systems. The natural question is whether migration is an inherent component for an efficient scheduling algorithm in either the online or offline setting. Leonardi and Raz [Proceedings of the Twenty-Ninth Annual ACM Symposium on Theory of Computing, El Paso, TX, 1997, pp. 110--119] showed that the well-known algorithm, shortest remaining processing time (SRPT), performs within a logarithmic factor of the optimal offline algorithm. Note that SRPT must use both preemption and migration to schedule the jobs. It is not known if better approximation factors can be reached and thus SRPT, although it is an online algorithm, becomes the best known algorithm in the offline setting. In fact, in the online setting, Leonardi and Raz showed that no algorithm can achieve a better bound. Without migration, no (offline or online) approximations are known. This paper introduces a new algorithm that does not use migration, works online, and is just as effective (in terms of approximation ratio) as the best known offline algorithm that uses migration.
Scheduling master-slave multiprocessor systems

The author defines the master-slave multiprocessor scheduling model in which a master processor coordinates the activities of several slave processors. O(n log n) centralized, deterministic, batch-oriented algorithms are developed for some of the problems formulated. Some others are shown to be NP-hard.
Including Foreshocks and Aftershocks in Time‐Independent Probabilistic Seismic‐Hazard Analyses

Time‐independent probabilistic seismic‐hazard analysis treats each source as being temporally and spatially independent; hence foreshocks and aftershocks, which are both spatially and temporally dependent on the mainshock, are removed from earthquake catalogs. Yet, intuitively, these earthquakes should be considered part of the seismic hazard, capable of producing damaging ground motions. In this study, I consider the mainshock and its dependents as a time‐independent cluster, each cluster being temporally and spatially independent from any other. The cluster has a recurrence time of the mainshock; and, by considering the earthquakes in the cluster as a union of events, dependent events have an opportunity to contribute to seismic ground motions and hazard. Based on the methods of the U.S. Geological Survey for a high‐hazard site, the inclusion of dependent events causes ground motions that are exceeded at probability levels of engineering interest to increase by about 10% but could be as high as 20% if variations in aftershock productivity can be accounted for reliably.
UNSTABLE BAR AND SPIRAL MODES OF DISK GALAXIES

We present new analytical and numerical results for modes of flat stellar disks that lie in potentials with soft centers. Stars primarily circulate in one direction. We identify two modes of angular wavenumber 2: a more central fundamental mode and a more extensive and more spiral (trailing) secondary mode. The fundamental mode is particularly sensitive to the population of stars of low angular momentum. Depending on that population, a small fraction of the whole, the fundamental mode varies from a small compact bar to a trailing spiral that is almost as wound as the secondary mode. Modes transfer angular momentum from the central to the outer regions of the disk. Most of them release gravitational energy and convert it to kinetic energy, which also flows outward through the disk. Few Fourier components contribute significantly to this transfer. All modes rotate too rapidly to have an inner Lindblad resonance and are unstable unless there is a sufficiently large external halo or bulge.
Spatial networks evolving to reduce length

Motivated by results of Henry, Pralat and Zhang (PNAS 108.21 (2011): 8605-8610), we propose a general scheme for evolving spatial networks in order to reduce their total edge lengths. We study the properties of the equilbria of two networks from this class, which interpolate between three well studied objects: the Erd} os-R enyi random graph, the random geometric graph, and the minimum spanning tree. The rst of our two evolutions can be used as a model for a social network where individuals have xed opinions about a number of issues and adjust their ties to be connected to people with similar views. The second evolution which preserves the connectivity of the network has potential applications in the design of transportation networks and other distribution systems.
Multihead two-way probabilistic finite automata

We present properties of multihead two-way probabilistic finite automata that parallel those of their deterministic and nondeterministic counterparts. We define multihead probabilistic finite automata withlogspace constructible transition probabilities, and we describe a technique to simulate these automata by standard logspace probabilistic Turing machines. Next, we represent logspace probabilistic complexity classes as proper hierarchies based on corresponding multihead two-way probabilistic finite automata, and we show their (deterministic logspace) reducibility to the second levels of these hierarchies. We obtain a simple formula for the maximum inherent bandwidth of the configuration transition matrices associated with thek-head probabilistic finite automata processing a length-n input string. (The inherent bandwidth of the configuration transition matrices associated with an automaton processing a length-n input string is the smallest bandwidth we can get by changing the enumeration order of the automaton’s configurations.) Partially based on this relation, we find an apparently easier logspace complete problem forPL (the class of languages recognized by logspace unbounded-error probabilistic Turing machines), and we discuss possibilities for a space-efficient deterministic simulation of probabilistic automata.
Static domain walls in N = 1 supergravity

Abstract We study supersymmetric domain walls in N = 1 supergravity theories, including those with modular-invariant superpotentials arising in superstring compactifications. Such domain walls are shown to saturate the Bogomol'nyi bound of wall energy per unit area. We find static and reflection asymmetric domain wall solutions of the self-duality equations for the metric and the matter fields. Such solutions interpolate between nondegenerate supersymmetric minima of the matter potential. Our result establishes a new class of domain walls beyond those previously classified. As a corollary, we define a precise notion of vacuum degeneracy in the supergravity theories. In addition, we found examples of global supersymmetric domain walls that do not have an analog when gravity is turned on. This result establishes that in the case of extended topological defects gravity plays a crucial, nontrivial role.
Instability of a cantilever under a follower force according to Timoshenko beam theory.

Stability of cantilevered elastic bar with end under compressive follower force, noting shear deformation, rotationary inertia and internal damping forces
Stability of a model of relativistic quantum electrodynamics

The relativistic “no pair” model of quantum electrodynamics uses the Dirac operator, D(A) for the electron dynamics together with the usual self-energy of the quantized ultraviolet cutoff electromagnetic field A — in the Coulomb gauge. There are no positrons because the electron wave functions are constrained to lie in the positive spectral subspace of some Dirac operator, D, but the model is defined for any number, N, of electrons, and hence describes a true many-body system. In addition to the electrons there are a number, K, of fixed nuclei with charges ≤ Z. If the fields are not quantized but are classical, it was shown earlier that such a model is always unstable (the ground state energy E = − ∞) if one uses the customary D(0) to define the electron space, but is stable (E < −const. (N + K)) if one uses D(A) itself (provided the fine structure constant α and Z are not too large). This result is extended to quantized fields here, and stability is proved for α 1/137 and Z ≤ 42. This formulation of QED is somewhat unusual because it means that the electron Hilbert space is inextricably linked to the photon Fock space. But such a linkage appears to better describe the real world of photons and electrons.
Teaching Old Indicators New Tricks

Most synthetic sensors are designed with covalent attachment between a receptor and a reporter moiety. In this report, we describe the current progress of our use of noncovalently attached indicators to signal binding of analytes. With these systems, analyte binding leads to indicator displacement from the binding cavity, which in turn yields an optical signal modulation. We include previous examples, the strategies involved in our development, and the advantages as well as disadvantages of this method. Finally, our latest research in this field is briefly presented.
Wave packet parametrices for evolutions governed by pdo’s with rough symbols

Author(s): Marzuola, Jeremy; Metcalfe, Jason; Tataru, Daniel | Abstract: In this note, we consider wave packet parametrices for Schrodinger-like evolution equations. Under an integrability condition along the flow, we prove that the flow is then globally well-defined and bilipschitz. Under an additional smallness assumption, we prove that the kernel of the phase space operator decays rapidly away from the graph of the Hamilton flow. This can be used to prove that smoothness is preserved for finite times by the flow of the equation.
Asymptotically liberating sequences of random unitary matrices

A fundamental result of free probability theory due to Voiculescu and subsequently refined by many authors states that conjugation by independent Haar-distributed random unitary matrices delivers asymptotic freeness. In this paper we exhibit many other systems of random unitary matrices that, when used for conjugation, lead to freeness. We do so by first proving a general result asserting “asymptotic liberation” under quite mild conditions, and then we explain how to specialize these general results in a striking way by exploiting Hadamard matrices. In particular, we recover and generalize results of the second-named author and of Tulino, Caire, Shamai and Verdu.
Supercapacitor Cycle Life Equalization in a Microgrid Through Flexible Distribution of Energy and Storage Resources

Industrial microgrids functioning under islanded mode of operation are often subjected to large and fluctuating demands from loads such as crushers, excavators, and steel rolling mills. This paper studies the supercapacitor (SC) cycle life when multiple small rated but distantly located distributed energy resources are supplying a cement plant crusher-conveyor load in the islanded operation of the microgrid. Each DER consists of a fuel cell (FC) supplemented with a SC. After having carried out extensive modeling, simulation, and analysis, this paper demonstrates that the SC cycle life can be equalized by employing the cooperative framework of flexible distribution of energy and storage resources.
Optimal replication algorithms for hierarchical mobility management in PCS networks

In the context of heterogeneous networks and diverse communication devices, real person-to-person communication can be achieved with a universal personal identification (UPI) that uniquely identifies an individual and is independent of the access networks and communication devices. Hierarchical mobility management techniques (MMTs) have been proposed to support UPI. Traditional replication methods for improving the performance of such MMTs are threshold based. In this paper, we present optimal replication algorithms that minimize the network messaging cost based on network structure, communication link cost, and user calling and mobility statistics. We develop our algorithms for both unicast and multicast replica update strategies. The performance of these replication algorithms is studied via large scale network simulations and compared to results obtained from the threshold-based method.
Triple Bars and Complex Central Structures in Disk Galaxies

We present an analysis of ground-based and Hubble Space Telescope images of three early-type barred galaxies. The first, NGC 2681, may be the clearest example yet of a galaxy with three concentric bars. The two other galaxies were previously suggested to be triple barred. Our analysis shows that while NGC 3945 is probably double barred, NGC 4371 has only one bar; but both have intriguing central structures. NGC 3945 has a large, extremely bright disk inside its primary bar, with patchy dust lanes, a faint nuclear ring or pseudoring within the disk, and an apparent secondary bar crossing the ring. NGC 4371 has a bright nuclear ring that is only marginally bluer than the surrounding bulge and bar. There is no evidence for significant dust or star formation in either of these nuclear rings. The presence of stellar nuclear rings suggests that the centers of these galaxies are dynamically cool and disklike.
Explicit unobstructed primes for modular deformation problems of squarefree level

Abstract Let f be a newform of weight k ⩾ 3 with Fourier coefficients in a number field K. We give explicit bounds on the set of primes λ of K for which the deformation problem associated to the mod λ Galois representation of f is obstructed. We include some explicit examples.
FFTs in external or hierarchical memory

Conventional algorithms for computing large one-dimensional fast Fourier transforms (FFTs), even those algorithms recently developed for vector and parallel computers, are largely unsuitable for systems with external or hierarchical memory. The principal reason for this is the fact that most FFT algorithms require at least m complete passes through the data set to compute a 2 m -point FFT. This paper describes some advanced techniques for computing an ordered FFT on a computer with external or hierarchical memory. These algorithms (1) require as few as two passes through the external data set, (2) employ strictly unit stride, long vector transfers between main memory and external storage, (3) require only a modest amount of scratch space in main memory, and (4) are well suited for vector and parallel computation. Performance figures are included for implementations of some of these algorithms on Cray supercomputers. Of interest is the fact that a main memory version outperforms the current Cray library FFT routines on the CRAY-2, the CRAY X-MP, and the CRAY Y-MP systems. Using all eight processors on the CRAY Y-MP, this main memory routine runs at nearly two gigaflops.