cssi/SciSciGPT-SciSciNet huggingface dataset:
CfA4: LIGHT CURVES FOR 94 TYPE Ia SUPERNOVAE

We present multi-band optical photometry of 94 spectroscopically confirmed Type Ia supernovae (SNe Ia) in the redshift range 0.0055-0.073, obtained between 2006 and 2011. There are a total of 5522 light-curve points. We show that our natural-system SN photometry has a precision of 0.03 mag in BVr'i', 0.06 mag in u', and 0.07 mag in U for points brighter than 17.5 mag and estimate that it has a systematic uncertainty of 0.014, 0.010, 0.012, 0.014, 0.046, and 0.073 mag in BVr'i'u'U, respectively. Comparisons of our standard-system photometry with published SN Ia light curves and comparison stars reveal mean agreement across samples in the range of ~0.00-0.03 mag. We discuss the recent measurements of our telescope-plus-detector throughput by direct monochromatic illumination by Cramer et al. This technique measures the whole optical path through the telescope, auxiliary optics, filters, and detector under the same conditions used to make SN measurements. Extremely well characterized natural-system passbands (both in wavelength and over time) are crucial for the next generation of SN Ia photometry to reach the 0.01 mag accuracy level. The current sample of low-z SNe Ia is now sufficiently large to remove most of the statistical sampling error from the dark-energy error budget. But pursuing the dark-energy systematic errors by determining highly accurate detector passbands, combining optical and near-infrared (NIR) photometry and spectra, using the nearby sample to illuminate the population properties of SNe Ia, and measuring the local departures from the Hubble flow will benefit from larger, carefully measured nearby samples.
Electrophysiological effects of amphetamine on dopaminergic neurons

Publisher Summary This chapter elaborates the electrophysiological effects of amphetamine on dopaminergic neurons. Antipsychotic phenothiazines and haloperidol were shown to reverse, and block the depressant effect of d-AMP. In addition, one found that blockade of DA synthesis by the intra-peritoneal administration of 50 mg/kg of the tyrosine hydroxylase inhibitor, α-methyl-p-tyrosine prevented, and reversed the slowing of DA cells induced by intravenous d-AMP. It is found that when the blockade of DA synthesis by AMPT was bypassed by the intravenous administration of the immediate precursor of DA/dihydroxyphenylalanine, the cell firing rate again decreased. The results suggest that ongoing DA synthesis is necessary for d-AMP to exert its effect, and that DA receptors may be involved in d-AMPs ability to depress DA neurons. In contrast to the minimal response of DA cells to iontophoretic d-AMP, one found postsynaptic cells in the caudate nucleus, accumbens nucleus, and olfactory tubercles that were markedly depressed by low ejection currents of d-AMP, and DA.
Bistatic synthetic aperture radar inversion with application in dynamic object imaging

An inversion method is presented for bistatic synthetic aperture radar imaging. The method is based on a Fourier analysis (Doppler processing) of the bistatic synthesized array's data followed by a phase modulation analysis of the Doppler data. The Doppler data are shown to provide samples of the reflectivity function's spatial Fourier transform within a band that depends upon the bistatic angles and ranges. Finally, the bistatic SAR inversion is used to formulate an inversion for multistatic measurements made along a physical linear array due to a single transmission to image a dynamic object. >
Investigation of the leeward side of a delta wing at hypersonic speeds.

A series of experiments were performed at Mm — 10 using a delta wing with sharp leading edges swept to 75°. Surface oil-flow measurements and impact pressure data were acquired in the lee-side region. Analysis of the results led to a description of the principal features of the flowfield. Results of the impact pressure survey indicated that, to a good approximation, the flowfield was conical. A theoretical analysis in two dimensions was utilized to calculate the in viscid flow properties.
A computational analysis of the structural features and reactive behavior of some heterocyclic aromatic N-oxides

Abstract An ab initio self-consistent-field molecular orbital analysis of the structural features and reactive behavior of pyridine, pyrazine and some of their N -oxide and nitro derivatives has been carried out. Optimized structures have been computed at the 6-31G ∗ level, yielding geometries in good agreement with experiment. These structures have been used to compute STO-5G electrostatic potentials and average local ionization energies on the respective molecular surfaces. There is considerable conjugation between the N -oxide groups and the aromatic rings, leading to significant para -quinonoid influence, manifested both in terms of structures and reactive properties. The charge-donor role of the N -oxide group allows the aromatic ring in pyridine N -oxide to be susceptible to electrophiles (at the para position) as well as nucleophiles; however, the rings in the pyrazine oxides are only receptive to the latter. The local ionization energies have permitted predictions of pK a values for pyrazine N -oxide and p -nitropyridine.
Plasma Polymerization of Sulfonated Fluorochlorocarbon Ionomer Films

Sulfonated fluorochlorocarbon ionomer films were prepared by radio frequency plasma polymerization of trifluorochloroethylene (TFCE) and trifluoromethane sulfonic acid (TFMSA). The TFMSA was introduced into the plasma chamber by bubbling a carrier gas through a vessel containing the neat acid. We show that the sulfonate content of the film prepared can be controlled by varying the temperature of the TFMSA‐containing vessel. We also show that films with high sulfonate contents can be prepared by using TFCE as the carrier gas for the TFMSA and then allowing this gas mixture to sustain the plasma. This may be contrasted to previous experiments of this type, where Ar was used to sustain the plasma and as the carrier gas. To our knowledge, this approach (i.e., of using the reactant gases to support the plasma) has never been used in the synthesis of plasma‐polymerized films. Finally, we have measured the ionic conductivities of the plasma‐polymerized films. The films prepared from the TFCE plasma are an order of magnitude more conductive than the films prepared from the Ar plasma.
Intramolecular Anodic Olefin Coupling Reactions and the Synthesis of Cyclic Amines

Anodic olefin coupling reactions using a tosylamine trapping group have been studied. The cyclizations are favored by the use of a less-polar radical cation and more basic reaction conditions. The most significant factor for obtaining good yields of cyclic product is the use of the more basic reaction conditions. However, a number of factors including the nature of both the solvent and the electrolyte used can influence the yield of the cyclizations. The cyclizations allow for the rapid synthesis of both substituted proline and pipecolic acid type derivatives.
A model for nonlinear rotary slosh in propellant tanks

A compound pendulum model is developed to predict rotary slosh of liquid in a scale model Centaur propellant tank at low fill level. A portion of the liquid behaves as a spherical pendulum that experiences rotary motion throughout a frequency range below, at, and above first mode resonance. The remainder of the fluid behaves as an ordinary linear pendulum. Phasing of the rotary motion is such that it subtracts from the effects of normal slosh below resonance and adds to the effects above resonance. The compound pendulum experiences analogous responses to that observed experimentally for the liquid, including bivalued states and jump phenomena, in a range just above resonance. Its responses are used to predict the effective weight response of the liquid by assigning pendulum mass, frequency, and damping parameters based on experimental measurements. An especially important result is that a significant magnitude cross-axis force exists for the rotary motion. This force is predicted by the compound pendulum model, but it is not predicted by the usual linear theory models.
EQUIVALENCE OF HIGHER TORSION INVARIANTS

Abstract We show that the smooth torsion of bundles of manifolds constructed by Dwyer, Weiss, and Williams satisfies the axioms for higher torsion developed by Igusa. As a consequence we obtain that the smooth Dwyer–Weiss–Williams torsion is proportional to the higher torsion of Igusa and Klein.
Supersymmetric Wilson loops, superstring-like observables, and the natural coupling of superstrings to supersymmetric gauge theories

Abstract We obtain an explicit expression for the supersymmetric Wilson loop in terms of chiral superfields and supercurrents in superspace. In the abelian supersymmetric gauge theories, generalizing the super-particle coupling represented by the exponent of the supersymmetric Wilson loop, we show that there exists a unique dimensionless coupling of a superstring to abelian supersymmetric gauge theories that respects all known symmetries. The coupling is expressed in terms of chiral currents in superspace. This dimensionless superstring coupling gives rise to a new observable that is “stringy” in nature and has no analogue in non-supersymmetric gauge theories.
A new light synthesis optimization program. Test on simulated Algol data

Simulation of light curve effects in Algol systems that are near contact or that may evolve into contact requires a different model than the tri-axial ellipsoid used in many current studies. A new light synthesis optimization program, based on the Roche model, satisfies the model requirements and determines system parameters with excellent accuracy, given a sufficiently large set of observations.
Prospects for hydrogen production by water electrolysis to be competitive with conventional methods

Abstract With the impending unavailability of oil and natural gas, hydrogen will be produced on a large scale in the United States (1) from coal, or (2) by water electrolysis using electricity derived from nuclear or solar energy. In many parts of the world which lack fossil fuels, the latter will be the only possible method. The cost of purification of hydrogen produced from fossil fuels will increase its cost to about the same level as that of electrolytic hydrogen. When hydrogen is required in relatively small quantities too, the electrolytic method is advantageous. To minimize the cost of hydrogen produced by water electrolysis, it is necessary to reduce capital costs and approach 100% energy efficiencies. Areas of research, which will be necessary to achieve these goals are: (1) maximization of surface areas of electrodes; (2) use of thin electrolyte layers; (3) increase of operating temperature in alkaline water electrolysis cells to about 120–150°C; (4) selection and evaluation of separator materials; (5) electrocatalysis of the hydrogen and oxygen electrode reaction; (6) mixed oxides as oxygen electrodes; and (7) photoelectrochemical effects. The progress made to date and proposed studies on these topics are briefly dealt with in this paper. The General Electric Solid Polymer Water Electrolyzer and Teledyne Alkaline Water Electrolysis Cells, operating at about 120–150°C, look most promising in achieving the goals of low capital cost and high energy efficiency.
VORTEX BREAKDOWN OVER A PITCHING DELTA WING

Unsteady pressure measurements were carried out on a pitching delta wing in order to study the effects of pressure gradient on the phase lag between the wing motion and the movement of breakdown location. The results indicate that the observed time lag of breakdown location is strongly linked to the external pressure gradient generated by the wing.
Advances in Old-Fashioned Heterotic String Model Building

Abstract I review findings of various research groups regarding perturbative heterotic string model building in the last 12 months. Attention is given to recent studies of extra U(1)'s and local discrete symmetries (LDS's) in generic string models. Issues covered include the role of U(1)'s and LDS's in limiting proton decay, developments in classification of models containing anomalous U(1), and possible complications resulting from kinetic mixing between observable and hidden sector U(1)'s. Additionally, recent string-derived and string-inspired models are briefly reviewed.
Localized Polynomial Frames on the Interval with Jacobi Weights

As is well known the kernel of the orthogonal projector onto the polynomials of degree n in L2(wα,β, [−1, 1]), wα,β(t) = (1 − t)α(1 + t)β, can be written in terms of Jacobi polynomials. It is shown that if the coefficients in this kernel are smoothed out by sampling a compactly supported C∞ function then the resulting function has nearly exponential (faster than any polynomial) rate of decay away from the main diagonal. This result is used for the construction of tight polynomial frames for L2(wα,β) with elements having almost exponential localization.
High-resolution saturation spectroscopy of singly-ionized iron with a pulsed UV laser

We describe the design and realization of a scheme for UV laser spectroscopy of singly-ionized iron (Fe II) with very high resolution. A buffer-gas cooled laser ablation source is used to provide a room-temperature plasma with a high density of Fe II. We combine this with a scheme for pulsed-laser saturation spectroscopy to yield sub-Doppler resolution. In a demonstration experiment, we have examined an Fe II transition near 260 nm, attaining a linewidth of about 250 MHz. The method is well suited to measure transition frequencies and hyperfine structure. It could also be used to measure small isotope shifts in isotope-enriched samples.
Torsion-balance tests of the weak equivalence principle

We briefly summarize motivations for testing the weak equivalence principle and then review recent torsion-balance results that compare the differential accelerations of beryllium–aluminum and beryllium–titanium test-body pairs with precisions at the part in 1013 level. We discuss some implications of these results for the gravitational properties of antimatter and dark matter and speculate about the prospects for further improvements in experimental sensitivity.
Kinetics and thermochemistry of the methyl radical: Study of the CH3 + HCl reaction

The kinetics of the reaction between CH3 and HCl was studied in a tubular reactor coupled to a photoionization mass spectrometer. Rate constants were measured as a function of temperature (296–495 K) and were fitted to an Arrhenius expression: k1 = 5.0(±0.7) × 10−13 exp{−1.4(±0.3) kcal mol−1/RT} cm3 molecule−1 s−1. This information was combined with known kinetic parameters of the reverse reaction to obtain Second Law determinations of the methyl radical heat of formation {34.7(±0.6) kcal mol−1} and entropy {46(±2) cal mol−1 K−1} at 298 K. Using the known entropy of CH3, a more accurate Third Law determination of the CH3 heat of formation at this temperature was also obtained {34.8(±0.3) kcal mol−1}. The values of k1 obtained in this study are between those reported in prior investigations. The results were also used to test the accuracy of the thermochemical information which can be obtained from kinetic studies of R + HX (X = Cl, Br, I) reactions of the type described here.
Methanol Conversion for the Production of Hydrogen

The production of methanol from a variety of biomass sources is gaining favor. Several facilities exist or are under construction throughout the world to convert biogenerated methane from the decomposition of biomass into methanol using conventional steam reforming. Methanol is an excellent liquid-hydrogen-transport medium. When powered by hydrogen, fuel cells have the potential to be the cleanest and most efficient source of electricity for use by the automotive industry. On-board reforming of liquid hydrocarbon fuels is a viable alternative to the storage of compressed hydrogen. A problem in current reforming processes is the quantity of carbon monoxide (CO) produced. Our research is geared toward circumventing the production of carbon monoxide in methanol reforming through the development of novel reforming catalysts. By modifying a copper-based catalyst, we have produced several catalysts that retain their activity and high surface area after extended methanol reforming runs both with and without the addition of steam.
A Numerical Scheme for Dynamic Systems Containing Fractional Derivatives

This paper presents a numerical scheme for dynamic analysis of mechanical systems subjected to damping forces that are proportional to fractional derivatives of displacements. These equations appear in the modeling of frequency dependent viscoelastic damping of materials. In the scheme presented, the fractional differential equation governing the dynamics of a system is transformed into a set of differential equations with no fractional derivative terms. Using Laguerre integral formula, this set is converted to a set of first order ordinary differential equations, which are integrated using a numerical scheme to obtain the response of the system. In contrast to other numerical techniques, this method does not require one to store the past history of the response. Numerical studies show that the solution converges as the number of Laguerre node points increase. Further, results obtained using this scheme agree well with those obtained using analytical techniques.
Finding Linear Patterns of Complexity One

We study the following generalization of Roth's theorem for 3-term arithmetic progressions. For s>1, define a nontrivial s-configuration to be a set of s(s+1)/2 integers consisting of s distinct integers x_1,...,x_s as well as all the averages (x_i+x_j)/2. Our main result states that if a set A contained in {1,2,...,N} has density at least (log N)^{-c(s)} for some positive constant c(s)>0 depending on s, then A contains a nontrivial s-configuration. We also deduce, as a corollary, an improvement of a problem involving sumfree subsets.
An experimental comparison between several active composite actuators for power generation

The use of piezoelectric materials for power harvesting has attracted significant interest over the past few years. The majority of research on this subject has sought to quantify the amount of energy generated in power harvesting applications, or to develop methods of improving the amount of energy generated. Usually, a monolithic piezoelectric material with a traditional electrode pattern and poled through its thickness is used for power harvesting. However, in recent years several companies and research institutions have begun to develop and market a broad range of piezoelectric composite sensor/actuator packages, each conceived for specific operational advantages and characteristics. Commonly, these devices are employed in control and vibration suppression applications, and their potential for use in power-harvesting systems remains largely unknown. Two frequently implemented design techniques for improving the performance of such actuators are the use of interdigitated electrodes and piezofibers. This paper seeks to experimentally quantify the differences in performance in power-harvesting applications between several of these new actuators and to identify the reasons for their relative performance characteristics. A special focus on the structural and compositional differences between each actuator is incorporated in the discussion of the effectiveness of each actuator as a power-harvesting device.
The multibank holding company effect on cost efficiency in banking

Abstract This paper tests the hypothesis that differences in the organizational form embodied in independent banks, one-bank holding companies, and multibank holding companies result in differences in operating cost efficiency. The transaction and agency cost paradigms for analysis of organizational efficiency provide theoretical motivation for the hypothesis. The effects of organizational form on bank operating expenses for individual banks are evaluated on subsamples divided into quartiles based on total revenue. Results indicate that for banks having revenues in the lowest quartile, both one-bank and multibank holding company affiliates are cost efficient relative to independent banks. Multibank holding company affiliates are cost efficient relative to both one-bank affiliates and independent banks for banks in the interquartile range. No significant differences in cost efficiency are noted banks in the highest revenue quartile. Relative efficiency at the organizational level is also evaluated. Results provide evidence of lower operating costs for banking operations of both multibank and one-bank holding company organizations relative to independent banks. Taken as a whole, the results imply that holding company affiliation conveys cost advantages to banking units below the 75th revenue percentile.
Leibniz cohomology and the calculus of variations

Abstract A geometric interpretation of the Leibniz coboundary is given in terms of the calculus of variations. For a differentiable manifold M , Leibniz cohomology generalizes de Rham cohomology by including all tensors as cochains. When applied to two-tensors, the conditions for the vanishing of a Leibniz cochain are related to the necessary conditions to achieve an extreme value of the integral of the tensor over an immersed surface. A local formula for the coboundary of any tensor is given in terms of a coordinate chart, and the Leibniz coboundary of the Riemann curvature tensor is computed in terms of the derivative of sectional curvature.
Comment on effective-Lagrangian formulations of the U(1) axial anomaly

Recent effective-Lagrangian formulations of the U(1) axial anomaly are examined to determine their consistency and the extent to which the fundamental quantum-chromodynamics theory is replicated. One formulation is shown to possess the desired properties, and some difficulties with two other formulations are pointed out.
Solving the open XXZ spin chain with nondiagonal boundary terms at roots of unity

We consider the open XXZ quantum spin chain with nondiagonal boundary terms. For bulk anisotropy value η=iπp+1, p=1,2,…, we propose an exact (p+1)-order functional relation for the transfer matrix, which implies Bethe-ansatz-like equations for the corresponding eigenvalues. The key observation is that the fused spin-p+12 transfer matrix can be expressed in terms of a lower-spin transfer matrix, resulting in the truncation of the fusion hierarchy.
Chronology protection in string theory

Many solutions of General Relativity appear to allow the possibility of time travel. This was initially a fascinating discovery, but geometries of this type violate causality, a basic physical law which is believed to be fundamental. Although string theory is a proposed fundamental theory of quantum gravity, geometries with closed timelike curves have resurfaced as solutions to its low energy equations of motion. In this paper, we will study the class of solutions to low energy effective supergravity theories related to the BMPV black hole and the rotating Wave-D1-D5-brane system. Time travel appears to be possible in these geometries. We will attempt to build the causality violating regions and propose that stringy effects prohibit their construction. We will show how the geometry is corrected and that, once corrected, causality is preserved. We will track our chronology protection proposal in the dual conformal field theory. The absence of closed timelike curves in the geometry coincides with the preservation of unitarity in the conformal field theory. The agent of chronology protection for the geometries studied here mirrors the enhancon mechanism, a mechanism string theory employs to resolve a class of naked singularities
Ex ante valuation of atmospheric visibility

In a world incomplete markets for environmental goods, ex ante planned expenditures rather than ex post realized outcomes explain the values which individuals attach to these goods. We use the distance function to develop restrictions from a model of ex ante consumer behaviour involving these goods. A Contigent valuation approach is then employed to estimate policy-relavant components of the ex ante economic values that recreationists attach to differing subjective probabilities of alternative atmospheric visibility levels at a wilderness location and at an urban location in Oregon. Marginal valuations of probability changes are similar at the two sites. Marginal rates of time preference for resolving uncertainities vary between 10 and 50% and are inversely related to education. Existence value averages 10% of total value, and evidence is mixed that site-specific value act as surrogates for general environmental preferences.
Dynamics of (n,1) strings

Abstract An (n,1) string is a bound state of a D-string and n fundamental strings. It may be described by a D-string with a world volume electric field turned on. As the electric field approaches its critical value, n becomes large. We calculate the 4-point function for transverse oscillations of an (n,1) string, and the two-point function for massless closed strings scattering off an (n,1) string. In both cases we find a set of poles that becomes dense in the large n limit. The effective tension that governs the spacing of these poles is the fundamental string tension divided by 1+(nλ)2, where λ is the closed string coupling. We associate this effective tension with the open strings attached to the (n,1) string, thereby governing its dynamics. We also argue that the effective coupling strenth of these open strings is reduced by the electric field and approaches zero in the large n limit.
The wound hormone jasmonate

Plant tissues are highly vulnerable to injury by herbivores, pathogens, mechanical stress, and other environmental insults. Optimal plant fitness in the face of these threats relies on complex signal transduction networks that link damage-associated signals to appropriate changes in metabolism, growth, and development. Many of these wound-induced adaptive responses are triggered by de novo synthesis of the plant hormone jasmonate (JA). Recent studies provide evidence that JA mediates systemic wound responses through distinct cell autonomous and non-autonomous pathways. In both pathways, bioactive JAs are recognized by an F-box protein-based receptor system that couples hormone binding to ubiquitin-dependent degradation of transcriptional repressor proteins. These results provide a framework for understanding how plants recognize and respond to tissue injury.
Spatial correlation and mobility-aware traffic modeling for wireless sensor networks

Recently, there has been a great deal of research on using mobility in wireless sensor networks (WSNs) to facilitate surveillance and reconnaissance in a wide deployment area. Besides providing an extended sensing coverage, node mobility along with spatial correlation introduces new network dynamics, which could lead to the traffic patterns fundamentally different from the traditional (Markovian) models. In this paper, a novel traffic modeling scheme for capturing these dynamics is proposed that takes into account the statistical patterns of node mobility and spatial correlation. The contributions made in this paper are twofold. First, it is shown that the joint effects of mobility and spatial correlation can lead to bursty traffic. More specifically, a high mobility variance and small spatial correlation can give rise to pseudo-long-range-dependent (LRD) traffic (high bursty traffic), whose autocorrelation function decays slowly and hyperbolically up to a certain cutoff time lag. Second, due to the ad hoc nature of WSNs, certain relay nodes may have several routes passing through them, necessitating local traffic aggregations. At these relay nodes, our model predicts that the aggregated traffic also exhibits the bursty behavior characterized by a scaled power-law decayed autocovariance function. According to these findings, a novel traffic shaping protocol using movement coordination is proposed to facilitate effective and efficient resource provisioning strategy. Finally, simulation results reveal a close agreement between the traffic pattern predicted by our theoretical model and the simulated transmissions from multiple independent sources, under specific bounds of the observation intervals.
SMC complexes link gene expression and genome architecture

The structural maintenance of chromosomes (SMC) complexes are associated with transcriptional enhancers, promoters and insulators, where they contribute to the control of gene expression and genome structure. We review here recent insights into the interlinked roles of SMC complexes in gene expression and genome architecture. Among these, we note evidence that SMC complexes play important roles in the regulation of genes that control cell identity. We conclude by reviewing diseases associated with SMC mutations.
Synthesis of Substituted Phenothiazines Analogous to Methylene Blue by Electrophilic and Nucleophilic Aromatic Substitutions in Tandem. a Mechanistic Perspective

Abstract 3,7-Disubstituted phenothiazines analogous to methylene blue (1) were synthesized from phenothiazine (6) reacting first with an excess of bromine in acetic acid to give 3,7-dibromophenothiazin-5-ium bromide (8), according to a reaction sequence that involves two electrophilic aromatic substitutions and one oxidation. Subsequently, 8 reacting with diallylamine or allylmethylamine via two nucleophilic aromatic substitution steps gave 3,7-bis[di(2-propenyl)amino]phenothiazin-5-ium bromide (3) or 3,7-bis[methyl, (2-propenyl)amino]phenothiazin-5-ium bromide (4), compounds analogous to methylene blue. The choice of solvent for the second step is critically important as 3,7-dibromophenothiazin-5-ium bromide is very reactive and prone to irreversible oxidation, reduction, and ipso attack at the 3- and 7-positions. The best yields (∼63%) for the methylene blue analogues 3 and 4 were obtained when CHCl3 or CH2Cl2 were employed as solvents for the nucleophilic aromatic substitution step. These solvents dissolve the methylene blue analogue products, but not 3,7-dibromophenothiazin-5-ium bromide. © 1997 Elsevier Science Ltd.
Arylation of Heterocycles via Rhodium-Catalyzed C−H Bond Functionalization

A new method for the rhodium-catalyzed arylation of a variety of heterocycles has been developed. The reaction provided moderate to good yields of the arylated products. A preliminary mechanistic investigation of this reaction revealed the intermediacy of an isolable N-heterocyclic carbene complex.
Two-dimensional matter: Order, curvature and defects

Many systems in nature and the synthetic world involve ordered arrangements of units on two-dimensional surfaces. We review here the fundamental role payed by both the topology of the underlying surface and its Gaussian curvature. Topology dictates certain broad features of the defect structure of the ground state but curvature-driven energetics control the detailed structure of the ordered phases. Among the surprises are the appearance in the ground state of structures that would normally be thermal excitations and thus prohibited at zero temperature. Examples include excess dislocations in the form of grain boundary scars for spherical crystals above a minimal system size, dislocation unbinding for toroidal hexatics, interstitial fractionalization in spherical crystals and the appearance of well-separated disclinations for toroidal crystals. Much of the analysis leads to universal predictions that do not depend on the details of the microscopic interactions that lead to order in the first place. These p...
Chelation controlled allylation of aldehydes with a chiral allylsilylene derived from (−)-10-phenylpinanediol

Abstract The chiral allylsilylene prepared from (−)-10-phenylpinanediol reacts with chiral α-alkoxy aldehydes in the presence of stannic chloride to afford homoallylic alcohols with diastereofacial selectivity ratios as high as 100:0. The results are consistent with attack of the allylsilylene on the less hindered face of the chelated intermediate. Our preliminary studies on several silylenes prepared from bicyclo[3.1.1] systems revealed that substituent effects on the chiral auxiliary and the silicon atom play an important role in the selectivity of these unique compounds.
A Lagrangian analysis of a developing and non-developing disturbance observed during the PREDICT experiment

Abstract. The problem of tropical cyclone formation requires among other things an improved understanding of recirculating flow regions on sub-synoptic scales in a time evolving flow with typically sparse real-time data. This recirculation problem has previously been approached assuming as a first approximation both a layer-wise two-dimensional and nearly steady flow in a co-moving frame with the parent tropical wave or disturbance. This paper provides an introduction of Lagrangian techniques for locating flow boundaries that encompass regions of recirculation in time-dependent flows that relax the steady flow approximation. Lagrangian methods detect recirculating regions from time-dependent data and offer a more complete methodology than the approximate steady framework. The Lagrangian reference frame follows particle trajectories so that flow boundaries which constrain particle transport can be viewed in a frame-independent setting. Finite-time Lagrangian scalar field methods from dynamical systems theory offer a way to compute boundaries from grids of particles seeded in and near a disturbance. The methods are applied to both a developing and non-developing disturbance observed during the recent pre-depression investigation of cloud systems in the tropics (PREDICT) experiment. The data for this analysis is derived from global forecast model output that assimilated the dropsonde observations as they were being collected by research aircraft. Since Lagrangian methods require trajectory integrations, we address some practical issues of using Lagrangian methods in the tropical cyclogenesis problem. Lagrangian diagnostics are used to evaluate the previously hypothesized import of dry air into ex-Gaston, which did not re-develop into a tropical cyclone, and the exclusion of dry air from pre-Karl, which did become a tropical cyclone and later a major hurricane.
A note on interface solutions in higher-spin gravity

In this paper we construct holographic interface solutions in the Chern-Simons formulation of higher-spin gravity. It is shown that the global regularity of the gauge connection imposes conditions on the conserved currents consistent with interface being totally transmissive or topological. An interface solution connecting the W3 and W (2) 3 vacuum is constructed in the SL(3;R) higher spin gravity. An interface solution corresponding to turning on relevant deformations in higher spin SL(4;R) gravity is presented.
NLO corrections in MC event generator for angular distribution of Drell-Yan lepton pair production

Using a subtraction method, we derive the formulae suitable for use in Monte-Carlo event generators to give the angular distribution for the gluon-quark induced NLO corrections in Drell-Yan lepton pair production. We also give the corresponding helicity density matrix for W and Z boson production.
Nietzsche and Aestheticism

Alexander Nehamas’s 1985 book Nietzsche: Life as a Literature offers an elegant synthesis of themes from other (then au courant) readings of Nietzsche by Jacques Derrida, Sarah Kofman, Paul DeMan, and Richard Rorty. He effected this synthesis primarily through the introduction of a novel interpretive rubric: what Nehamas calls "aestheticism." According to aestheticism, "Nietzsche... looks at [the world] as if it were a literary text. And he arrives at many of his views of human beings by generalizing to them ideas and principles that apply almost intuitively to the literary situation, to the creation and interpretation of literary texts and characters". For Nehamas, then, the literary text is Nietzsche's "overarching metaphor" (164), the "model" he "always depended on" (194) in pursuing his philosophical inquiries, "the single thread running through" his work. I show that aestheticism is, in fact, not Nietzsche’s view, and that Nehamas fails to adduce a single passage from Nietzsche in which he actually embraces aestheticism. I also show how aestheticism leads Nehamas to an idiosyncratic reading of Nietzsche’s "positive" ethical views. I conclude that this intelligent but sometimes idiosyncratic book is not really about Nietzsche.
A practical, distributed environment for Macintosh software development

We describe a development environment we created for prototyping software for the Macintosh. The programs are developed and executed on a large time-shared computer but can use the full facilities of the Macintosh. By using this system, we combine the advantages of the large system, such as large amounts of disk storage and automatic file backups, with the advantages of the Macintosh, such as advanced graphics, mouse control and sound synthesis. We also describe several projects that used the distributed development system. We conclude with a description of our future plans for this environment.
QCDF90: a set of Fortran 90 modules for a high-level, efficient implementation of QCD simulations

Abstract We present a complete set of Fortran 90 modules that can be used to write very compact, efficient, and high level QCD programs. The modules define fields (gauge, fermi, generators, complex, and real fields) as abstract data types, together with simpler objects such as SU (3) matrices or color vectors. Overloaded operators are then defined to perform all possible operations between the fields that may be required in a QCD simulation. QCD programs written using these modules need not have cumbersome subroutines and can be very simple and transparent. This is illustrated with two simple example programs.
Resonant Generation of Internal Waves on a Model Continental Slope

We study internal wave generation in a laboratory model of oscillating tidal flow on a continental margin. Waves are found to be generated only in a near-critical region where the slope of the bottom topography matches that of internal waves. Fluid motion with a velocity an order of magnitude larger than that of the forcing occurs within a thin boundary layer above the bottom surface. The resonant wave is unstable because of strong shear; Kelvin-Helmholtz billows precede wave breaking. This work provides a new explanation for the intense boundary flows on continental slopes.
Long Time Results for a Weakly Interacting Particle System in Discrete Time

We study long time behavior of a discrete time weakly interacting particle system, and the corresponding nonlinear Markov process in , described in terms of a general stochastic evolution equation. In a setting where the state space of the particles is compact such questions have been studied in previous works, however, for the case of an unbounded state space very few results are available. Under suitable assumptions on the problem data we study several time asymptotic properties of the N-particle system and the associated nonlinear Markov chain. In particular, we show that the evolution equation for the law of the nonlinear Markov chain has a unique fixed point and starting from an arbitrary initial condition convergence to the fixed point occurs at an exponential rate. The empirical measure μNn of the N-particles at time n is shown to converge to the law μn of the nonlinear Markov process at time n, in the Wasserstein-1 distance, in L1, as N → ∞, uniformly in n. Several consequences of this uniform con...
Bearing Failure in Pin Contact of Composite Laminates

A fiber-microbuc kling-based failure model for contact between a pin and a composite laminate was reviewed. In this paper, this failure model was employed to study the effects of various parameters on the bearing failure. The parameters considered included ply orientation, stacking sequence, laminate thickness, pin material, and clamping condition. Accompanying the analysis, pin contact experiments were conducted. The test results' demonstrated the influence of these parameters on the contact bearing strength. They were also used to evaluate the model predictions. Several bearing failure mechanisms were found to be dependent upon ply thickness and orientation. If the failure was dominated by fiber microbuckling, then the present model yielded quite accurate predictions of bearing failure.
THE DIFFERENCE BETWEEN METAL-POOR AND METAL-RICH BINARIES

In the past there have been many discrepant studies about whether metal-poor (Population II) stars were deficient in binaries or had approximately the same binary frequency as metal-rich stars. We consider here the distributions of periods in five samples of binaries: (1) 138 field halo binaries with low metal abundances ([Fe/H] −0.30 as listed on-line by Pourbaix, (4) 31 binaries among the well-studied FG dwarfs within 25 pc of the Sun, and (5) binaries in three open clusters with ages of 108-109 yr. The main result is that the metal-poor stars lack short-period binaries relative to the metal-rich stars; the period distributions are very different. This tells us two things. First, the determination of the frequency of discovered binaries for metal-poor and metal-rich stars will depend upon the equipment used: if one uses low-resolution spectrographs, one will detect many of the short-period binaries but not many of the long-period binaries and conclude that the metal-poor stars are deficient in binaries. If one uses higher resolution, as did Latham et al., one will detect many more binaries and conclude that there is no difference in binary frequency between metal-poor and metal-rich stars. Second, if binaries are formed in three-body interactions in clusters and, as n-body simulations show, the longer they remain in dense cluster environments, the harder (shorter periods) they become.
Analysis of an All-Metallic Resilient Pad Gas-Lubricated Thrust Bearing

A resilient-pad gas thrust bearing that does not contain any elastomers in the bearing assembly is described and analyzed. The bearing consists of sector-shaped pads mounted asymmetrically on resilient foil beams. The effects of bearing design parameters on performance are shown. Performance of a resilient-pad bearing is compared with that of a pivoted-pad bearing.
Matrix description of (1,0) theories in six dimensions

We propose descriptions of interacting (1,0) supersymmetric theories without gravity in six dimensions in the infinite momentum frame. They are based on the large N limit of quantum mechanics or 1+1 dimensional field theories with SO(N) gauge group and four supercharges. We argue that this formulation allows for a concrete description of the chirality-changing phase transitions which connect (1,0) theories with different numbers of tensor multiplets.
Rotational spectra of p-isopropylbenzaldehyde: assignment of two conformers and observation of torsionally excited states

Abstract Rotational spectra of p -isopropylbenzaldehyde were obtained at a very low temperature in a pulsed-beam Fourier transform-microwave spectrometer and over a range of much higher temperatures in a continuous wave spectrometer. Two species with ground-state rotational constants A =2975.15(14) MHz, B =550.1631(1) MHz, C =516.3000(1) MHz and A =3183.80(30) MHz, B =538.8124(1) MHz, C =512.0049(1) MHz were observed in the beam and are consistent with structures having the methine hydrogen coplanar with the benzene ring and respectively anti and syn to the carbonyl oxygen of the para formyl group. Relative intensities of the rotational transitions indicate that the two conformers have almost equal energies. Near room temperature, in addition to R-branch a -type band series consistent with the anti and syn conformers, a very intense band series with an intermediate B + C value is observed in the low-resolution microwave spectrum of p -isopropylbenzaldehyde, as previously reported [N.S. True, J. Phys. Chem., 87 (1983) 4622]. Temperature-dependent relative intensity measurements do not support the proposal of these authors that the intensity of this series reflects the population in torsional states above the torsional barrier and can be used to estimate the internal rotation barrier height. Additional factors not directly related to the free rotor population must contribute to the observed intensity.
Towards an Informational Pragmatic Realism

I discuss the design of the method of entropic inference as a general framework for reasoning under conditions of uncertainty. The main contribution of this discussion is to emphasize the pragmatic elements in the derivation. More specifically: (1) Probability theory is designed as the uniquely natural tool for representing states of incomplete information. (2) An epistemic notion of information is defined in terms of its relation to the Bayesian beliefs of ideally rational agents. (3) The method of updating from a prior to a posterior probability distribution is designed through an eliminative induction process that singles out the logarithmic relative entropy as the unique tool for inference. The resulting framework includes as special cases both MaxEnt and Bayes' rule. It therefore unifies entropic and Bayesian methods into a single general inference scheme. I find that similar pragmatic elements are an integral part of Putnam's internal realism, of Floridi's informational structural realism, and also of van Fraasen's empiricist structuralism. I conclude with the conjecture that their valuable insights can be incorporated into a single coherent doctrine--an informational pragmatic realism.
Wide-bandwidth analog correlator and its application to mode-locked laser measurements

A new instrument for the analog determination of correlation functions of wide-bandwidth signals is described and characterized. The instrument is comprised of microwave electronic components; a double-balanced mixer performs the multiplication operation involved in the correlation process, whereas a constant-impedance line stretcher introduces the variable delay. Measurements indicate that the correlator has a bandwidth of approximately 3 GHz. It is shown that this inexpensive and simple device can be used as a diagnostic tool for mode-locked argon-ion lasers when used in conjunction with a fast photodiode detector.
New discoveries at the interface of boron and carbon chemistries

The continued growth of polyhedral borane chemistry is illustrated by the success- ful synthesis of (closo-B 12 (OH) 12 ) 2- by the H 2 O 2 oxidation of (closo-B 12 H 12 ) 2- . The hy- droxylated species reacts with common organic reagents to produce 12-fold degenerately substituted carboxylate esters, ethers, and carbamate esters. The ether derivatives undergo facile and reversible redox reactions in which the B 12 scaffold serves as a one- or two-elec- tron donor giving stable oxidation states described by (closo- or hypercloso-B 12 (OR) 12 ) n with n = -2, -1, and 0. The loss of polyhedral electrons is compensated by back-bonding from the attached ether oxygen substituents. Structural comparisons are presented along with representative reaction chemistry. Derivatives that bear functional groups on the termini of the 12-fold set of substituents provide a vast array of potential applications. To distinguish these new polyfunctional icosahedral species from dendrimers, they have been designated as closomers.
Temporal price dispersion: Evidence from an online consumer electronics market

Economic theory indicates that e-retailers competing at price comparison sites, such as Shopper.com, must charge prices that cannot be systematically predicted by their rivals. Consistent with theory, we find significant variation in the identity of the low-price firm as well as the level of the lowest price for 36 of the best-selling consumer electronics products sold at Shopper.com between November 1999 and May 2001.The observed pricing patterns can be explained by firms engaging in short-term price promotions in an attempt to avoid the deleterious outcome associated with price competition. Based on our arguments and the evidence presented, the managerial implications are clear: Strategic unpredictability in prices—through the use of hit and run sales—is a widely used and effective weapon for avoiding all-out price competition in online markets.