cssi/SciSciGPT-SciSciNet huggingface dataset:
Intensity Distribution in Unresolved Electronic Bands of Diatomic and Symmetric-Top Molecules*†

The band spectra of molecules have been theoretically investigated under conditions when the individual line components within the band are unresolved. In particular, treatments for diatomic molecule bands, the symmetric top molecule perpendicular bands, and the symmetric-top molecule parallel bands, are given. This treatment indicates the methods which may be followed in order to determine the molecular constants or molecular moments of inertia from unresolved spectra. The theory is illustrated by the computation of the O,ON2+ band and the CH3Br fundamental band for the diatomic and symmetric-top perpendicular band cases, respectively. Some features of the A10, and B00 absorption bands of C6H6 are also discussed.
Human Evolutionary Research in Eastern Germany

Human evolutionary research in Eastern Germany, limited in this paper to the origins and evolution of Pleistocene man, has mainly focused during the last decade on theoretical aspects of the evolution of man and human society from multiple and interdisciplinary perspectives. An interdisciplinary working group «Probleme der Menschwerdung» was founded in 1977. About 30 specialists from various fields have discussed problems of the origins and evolution of man and human society under interdisciplinary aspects. The activities, difficulties and results of this cooperation will be outlined in this paper. There will also be given a progress report on the disciplinary initiated research on local sites as well as on general aspects and problems.
Analysis and design of ferroelectric-based smart antenna structures

Ferroelectrics in microwave antenna systems offer benefits of electronic tunability, compact size and light weight, speed of operation, high power-handling, low dc power consumption, and potential for low loss and cost. Ferroelectrics allow for the tuning of microwave devices by virtue of the nonlinear dependence of their dielectric permittivity on an applied electric field. Experiments on the field-polarization dependence of ferroelectric thin films show variation in dielectric permittivity of up to 50%. This is in contrast to the conventional dielectric materials used in electrical devices which have a relatively constant permittivity, indicative of the linear field-polarization curve. Ferroelectrics, with their variable dielectric constant introduce greater flexibility in correction and control of beam shapes and beam direction of antenna structures. The motivation behind this research is applying ferroelectrics to mechanical load bearing antenna structures, but in order to develop such structures, we need to understand not just the field-permittivity dependence, but also the coupled electro-thermo-mechanical behavior of ferroelectrics. In this paper, two models are discussed: a nonlinear phenomenological model relating the applied fields, strains and temperature to the dielectric permittivity based on the Devonshire thermodynamic framework, and a phenomenological model relating applied fields and temperature to the dielectric loss tangent. The models attempt to integrate the observed field-permittivity, strain-permittivity and temperature-permittivity behavior into one single unified model and extend the resulting model to better fit experimental data. Promising matches with experimental data are obtained. These relations, coupled with the expression for operating frequency vs. the permittivity are then used to understand the bias field vs. frequency behavior of the antenna. Finally, the effect of the macroscopic variables on the antenna radiation efficiency is discussed.
Rayed craters on the moon and Mercury

Abstract Many fresh craters on the moon and Mercury exhibit systems of bright rays. Statistical comparison of the diameter/density distributions of fresh craters and rayed craters on these two bodies indicate that the rayed-crater populations are representative samples of the larger populations of fresh craters. The rayed-crater population on Mercury, however, is not similar either to the rayed- or to the fresh-crater population on the moon. Photogeological interpretation of the best available lunar imagery indicates that “ray material” is indeed ejected from the primary craters, and should be present in the lunar soil. Although the distribution of the ray material may be patchy, it probably occurs in deposits of thickness greater than the characteristic depth to which subsequent impact processes overturn the regolith. The time needed to darken a ray system thus may be more dependent on the thickness of the ray material than on the rates of the various darkening processes, and darkening rate may be a function of crater size. Ray darkening on the lunar surface is an inefficient process at present. The rays of craters more than 1 b.y. old are still bright, whereas the rays of craters older than Class 1 have generally faded to imperceptibility.
Liquid Light and Accelerated Frames

The interaction of an accelerated detector with a Klein-Gordon relativistic wave field partitioned into two subsystems by the two Rindler coordinate charts of a pair of accelerated coordinate frames (PACF) is considered theoretically, reviewing the results of recent investigations. The properties of the Rindler vacuum are explored, and the nature of the photon dynamics, as determined by the total boost generator, is characterized. A calculation in the thermodynamic limit shows that a Rindler vacuum state relative to one PACF cannot be related via a unitary transformation to another Rindler vacuum state relative to a parallel translated PACF. It is concluded that a Klein-Gordon field can be prepared in any one of an infinite number of condensed vacuum states, all lying in different Hilbert spaces; i.e., that a Rindler vacuum state breaks translation symmetry. 15 refs.
Ceramic candle filter performance at the Grimethorpe (UK) Pressurized Fluidized Bed Combustor

A pilot hot-gas particulate removal system, based on positive porous ceramic filters, has been tested on the Grimethorpe Pressurized Fluidized Bed Combustor facility. The filters are in the form of closed-ended tubes, 1.5 m long: These are generally called candles. The dust accumulates on the outside of the cradles, and is periodically removed by a pulse of air into the candle interior, which then flows outward through the candle wall in the reverse direction to the normal flow of the combustion gas. The EPRI system contained a maximum of 130 candles, which is approximately equivalent to the requirement for 7 MW(e) capacity, depending on the filter-operating parameters. The filter unit operated for a total of 860 h under PFBC conditions, of which 790 h were at defined process conditions, typically 850{degrees}C and 10 bar. The amount of gas flowing through each filter element was varied, and the time between cleaning pulses also was varied. The pressure drop through each filter element rose as the dust accumulated on the outer wall, and recovered after the cleaning pulse.
Use of antipsychotic drugs in nursing homes: current compliance with OBRA regulations.

OBJECTIVE: To examine the degree and patterns of compliance with the Omnibus Budget Reconciliation Act (OBRA) regulations regarding the use of antipsychotic drugs in nursing homes. DESIGN: Retrospective chart review of all resident records. PARTICIPANTS: Eight nursing homes: five community, two county-owned, and one university-affiliated Veterans Administration facility. MEASUREMENTS: A structured assessment instrument to track compliance with each aspect of the OBRA regulations regarding antipsychotic drug use. RESULTS: A total of 1573 nursing home residents' pharmacy records were reviewed between August 1994 and March 1996. Two hundred seventy-nine residents were actively taking antipsychotic medications (prevalence = 17.7%). Mean compliance greater than 70% was found for (1) appropriate diagnostic indication (X = 70.9%), (2) dosage within recommended limits (X = 90.1%), and 3) documented appropriate target symptoms (X = 90.4%). Dosages were more likely to exceed limits in those patients with histories of major mental illness, particularly schizophrenia. CONCLUSIONS: Nursing homes were better able to comply with those guidelines that are most specific. Educational interventions now need to focus on behavioral interventions, monitoring of adverse effects, and efficacy. These data are useful in establishing threshold levels of performance and can be used by nursing homes for continuous quality improvement. OBRA continues to impact neuroleptic drug prescribing practices in nursing homes significantly.
Pyridine-derived triflating reagents : an improved preparation of vinyl triflates from metallo enolates

Abstract Metallo enolates of ketones are trapped with an N-(2-pyridyl)triflimide at low temperatures to give vinyl triflates.
International trade and the U.S. automobile industry: Current research, issues, and questions

Abstract This paper has dual goals. On the one hand, it attempts a review of recent econometric work on the U.S. automobile industry. Three studies of this industry are reviewed, compared, and contrasted. These are studies by Koujianou Goldberg [Koujianou Goldberg, P., 1993, U.S. trade policy implications of a new approach to modelling the demand for automobiles, mimeo (Princeton University)], Feenstra and Levinsohn [Feenstra, R. and J. Levinsohn, 1994, Estimating markups and market conduct with multidimensional product attributes, Review of Economic Studies, forthcoming] and Berry et al. [Berry, S., J. Levinsohn and A. Pakes, 1994, Automobile prices in market equilibrium, Econometrica, forthcoming]. On the other hand, a number of current policy issues facing the industry are also reviewed. These issues include the Voluntary Export Restraint applying to exports from Japan, the NAFTA, anti-dumping law, and industry globalization. The paper provides a broad overview, then, of econometric and policy issues as they relate to the U.S. automobile industry.
A construction of derived equivalent pairs of symmetric algebras

Recently, Hu and Xi have exhibited derived equivalent endomorphism rings arising from (relative) almost split sequences as well as AR-triangles in triangulated categories. We present a broader class of triangles (in algebraic triangulated categories) for which the endomorphism rings of different terms are derived equivalent. We then study applications involving 0-Calabi-Yau triangulated categories. In particular, applying our results in the category of perfect complexes over a symmetric algebra gives a nice way of producing pairs of derived equivalent symmetric algebras. Included in the examples we work out are some of the algebras of dihedral type with two or three simple modules. We also apply our results to stable categories of Cohen-Macaulay modules over odd-dimensional Gorenstein hypersurfaces having an isolated singularity.
The Tesserae Project: intertextual analysis of Latin poetry

Tesserae is a web-based tool for automatically detecting allusions in Latin poetry. Although still in the start-up phase, it already is capable of identifying significant numbers of known allusions, as well as similar numbers of allusions previously unnoticed by scholars. In this article, we use the tool to examine allusions to Vergil's Aeneid in the first book of Lucan's Civil War. Approximately 3,000 lin- guistic parallels returned by the program were compared with a list of known allusions drawn from commentaries. Each was examined individually and graded for its literary significance, in order to benchmark the program's performance. All allusions from the program and commentaries were then pooled in order to examine broad patterns in Lucan's allusive techniques which were largely unapproachable without digital methods. Although Lucan draws relatively con- stantly from Vergil's generic language in order to maintain the epic idiom, this baseline is punctuated by clusters of pointed allusions, in which Lucan frequently subverts Vergil's original meaning. These clusters not only attend the most sig- nificant characters and events but also play a role in structuring scene transitions. Work is under way to incorporate the ability to match on word meaning, phrase context, as well as metrical and phonological features into future versions of the program.
Seiberg duality is an exceptional mutation

The low energy gauge theory living on D-branes probing a del Pezzo singularity of a non-compact Calabi-Yau manifold is not unique. In fact there is a large equivalence class of such gauge theories related by Seiberg duality. As a step toward characterizing this class, we show that Seiberg duality can be defined consistently as an admissible mutation of a strongly exceptional collection of coherent sheaves.
Applications of Klee’s Dehn–Sommerville Relations

We use Klee’s Dehn–Sommerville relations and other results on face numbers of homology manifolds without boundary to (i) prove Kalai’s conjecture providing lower bounds on the f-vectors of an even-dimensional manifold with all but the middle Betti number vanishing, (ii) verify Kuhnel’s conjecture that gives an upper bound on the middle Betti number of a 2k-dimensional manifold in terms of k and the number of vertices, and (iii) partially prove Kuhnel’s conjecture providing upper bounds on other Betti numbers of odd- and even-dimensional manifolds. For manifolds with boundary, we derive an extension of Klee’s Dehn–Sommerville relations and strengthen Kalai’s result on the number of their edges.
Statement on the Breakfast Cereals Industry

This summary of my recommendations as advisor to the US District Court in an antitrust proceeding involving the acquisition by Post of Nabisco Cereals is based almost entirely on the evidence in that case. There is ample basis for dissatisfaction with the performance of the industry—especially with its comparative absence of everyday price competition, except where private brands bulk large. There is no reason to believe, however, that the merger at issue would weaken price competition or that if Nabisco were sold to some other entity it would be any more willing to dilute the value of its Shredded Wheat brand by selling product for private labeling. On the other hand, the merger would probably make the combined entity more effective in the ways in which the industry typically competes—including heavy distribution of coupons and specials, which are undeniably a form of price competition. [EconLit cites: L100, L410, L660] © 1999 John Wiley & Sons, Inc.
(−)‐3,6‐Dioxo‐5β‐cholanic acid: hydrogen bonding in the hemihydrate of a steroidal diketo acid

The hemihydrate of the title diketo acid, C24H36O4·0.5H2O, forms hydrogen-bonded carboxyl dimers related by a C2 axis at crystallographic sites on the a and b edges of the chosen cell [O⋯O = 2.643 (7) and 2.716 (7) A]. The ketone ends of the mol­ecules approach each other at sites near (½,½,½), (½,0,½), (0,0,½) and (0,½,½) in an interleaved arrangement incorporating partial-occupancy water hydrogen bonded to the B-ring ketone.
Propagation of uncertainty and analysis of signal-to-noise in nonlinear compliance estimations of an arterial system model

The arterial system dynamically loads the heart through changes in arterial compliance. The pressure-volume relation of arteries is known to be nonlinear, but arterial compliance is often modeled as a constant value, due to ease of estimation and interpretation. Incorporating nonlinear arterial compliance affords insight into the continuous variations of arterial compliance in a cardiac cycle and its effects on the heart, as the arterial system is coupled with the left ventricle. We recently proposed a method for estimating nonlinear compliance parameters that yielded good results under various vasoactive states. This study examines the performance of the proposed method by quantifying the uncertainty of the method in the presence of noise and propagating the uncertainty through the system model to analyze its effects on model predictions. Kernel density estimation used within a bootstrap Monte Carlo simulation showed the method to be stable for various vasoactive states.
Mount Hood Earthquake Activity: Volcanic or Tectonic Origins?

On 29 June 2002, a M D 4.5 earthquake occurred 4.6 km south of Mount Hood, Oregon. More than 200 small aftershocks ( M D ≤3.8) occurred between 29 June and 15 August 2002, by which time seismicity returned to background levels. We analyze well-constrained earthquakes from the summer 2002 sequence near Mount Hood, recorded by the Pacific Northwest Seismic Network (pnsn), and well-constrained, small earthquakes ( M D ≤3.5) recorded by the pnsn between 1986 and 2002. We apply waveform cross-correlation to selected events, establish a one-dimensional P -wave velocity model, and relocate the entire catalog by using the double-difference algorithm of Waldhauser and Ellsworth (2000). We find that earthquakes before 2002 occur in four distinct clusters: (A) a well-defined linear feature, striking N15E, about 5 km south of the summit, (B) a linear feature, trending northwest–southeast a few kilometers south of group A, (C) a few tight clusters located about 9 km south-southwest of the summit, and (D) a small cluster beneath the summit. Earthquakes in group D do not appear to lie on a fault and may relate to volcanic activity. However, almost all earthquakes in the 2002 swarm occur in group A, south of the summit, at depths similar to earthquakes from previous swarms. First-motion fault-plane solutions from the mainshock and largest aftershocks have normal mechanisms, and solutions from well-constrained aftershocks have normal to oblique normal mechanisms. This is consistent with the apparent strike of the feature south of Mount Hood’s summit and is similar to focal mechanisms of older earthquakes in group A. b - and p -values for the summer 2002 earthquakes resemble a tectonic mainshock-aftershock sequence. We interpret these earthquakes as the northernmost example of Basin-and-Range seismicity yet recorded and conclude that the Mount Hood earthquakes do not yet suggest potential for volcanic unrest.
Synthesis and structure of Nb3SiTe6, a new layered ternary niobium telluride compound

Abstract Nb3SiTe6, a new type of layered ternary telluride compound, has been synthesized. The structure is determined by single-crystal X-ray diffraction methods. The compound crystallizes in space group Pnma (No. 62) with Z=4, a=6.353(2) A , b=13.938(5) A , c=11.507(4) A , V=1018.9(6) A 3 , R=4.77% and R w =4.88% . The structure contains sheets of mixed niobium and silicon with tellurium atoms capping both sides. The layered framework has an unusual coordination environment.
LQG-MP: Optimized path planning for robots with motion uncertainty and imperfect state information

In this paper we present LQG-MP (linear-quadratic Gaussian motion planning), a new approach to robot motion planning that takes into account the sensors and the controller that will be used during the execution of the robotâs path. LQG-MP is based on the linear-quadratic controller with Gaussian models of uncertainty, and explicitly characterizes in advance (i.e. before execution) the a priori probability distributions of the state of the robot along its path. These distributions can be used to assess the quality of the path, for instance by computing the probability of avoiding collisions. Many methods can be used to generate the required ensemble of candidate paths from which the best path is selected; in this paper we report results using rapidly exploring random trees (RRT). We study the performance of LQG-MP with simulation experiments in three scenarios: (A) a kinodynamic car-like robot, (B) multi-robot planning with differential-drive robots, and (C) a 6-DOF serial manipulator. We also present a method that applies Kalman smoothing to make paths Ck-continuous and apply LQG-MP to precomputed roadmaps using a variant of Dijkstraâs algorithm to efficiently find high-quality paths.
Encoding of incompletely specified Boolean matrices

The problem discussed in this paper is a generalization of the problem of choosing the binary codes for the various operations of a digital computer with a view towards minimizing the gating circuitry in the computer's central control. The general procedure is a systematic method for the simultaneous encoding of a large number of arbitrary Boolean functions in an economical manner. The method is applicable to those cases where the designer is allowed to choose the independent variables so as to minimize the circuit which realizes the given Boolean functions. Other applications of the procedure are indicated. The method given includes a means for determining a lower bound on the cost of the circuit which realizes the given Boolean functions. The entire procedure is systematic and lends itself well to mechanization via a digital computer program. A discussion of the advantages and limitations of the method presented here is included, and the method is compared with a previously published procedure for attacking the same problem.
Glaucomatous disease in patients with normal pressure hydrocephalus.

PURPOSE To investigate the relative prevalence of glaucomatous disease in patients with normal pressure hydrocephalus (NPH) compared with age-matched non-NPH controls with hydrocephalus. DESIGN Case-control study. PARTICIPANTS Using International Classification of Diseases (ICD-9) codes, we identified the medical records of 72 NPH cases and 72 age-matched controls with hydrocephalus treated at Stanford University Hospital between 1996 and 2007. METHODS All available electronic medical records were reviewed. The diagnosis of NPH was verified based on clinical presentation, neuroimaging results, and opening pressure on initial access to cerebrospinal fluid space. Glaucoma status was determined based on history and prior medical, laser, or surgical intraocular pressure-lowering therapy. MAIN OUTCOME MEASURE The proportion of subjects determined as having glaucomatous disease in cases and controls. RESULTS The prevalence of glaucoma in NPH cases was estimated to be 18.1% in contrast to 5.6% in controls (chi=5.403, P=0.0201). The average age of NPH cases and non-NPH controls was 75.40+/-13.4 and 73.96+/-9.92 years (mean+/-SD), respectively. CONCLUSIONS We found the prevalence of a glaucoma diagnosis to be 3-fold greater in patients with NPH as compared with age-matched non-NPH controls with hydrocephalus. These findings suggest the possiblity of an association between these 2 neurodegenerative diseases which should be studied prospectively.
Asymmetric Synthesis of 2H-Azirine 2-Carboxylate Esters.

2H-Azirine 2-carboxylate esters (5), the smallest unsaturated nitrogen heterocycle, are readily prepared in enantiomerically pure form via the base-induced elimination of sulfenic acid (RSOH) from nonracemic N-sulfinylaziridine 2-carboxylate esters (4). Optimum yields were obtained when the aziridine was treated with TMSCl at −95 °C followed by LDA, which was attributed to the improved leaving group ability of an silicon−oxonium species. By using this new methodology the first asymmetric syntheses of the marine cytotoxic antibiotics (R)-(−)- and (S)-(+)-dysidazirine (2) were accomplished.
Dirac Particles in Twisted Tubes

Abstract We consider the dynamics of a relativistic Dirac particle constrained to move in the interior of a twisted tube by confining boundary conditions, in the approximation that the curvature of the tube is small and slowly varying. In contrast with the nonrelativistic theory, which predicts that a particle's spin does not change as the particle propagates along the tube, we find that the angular momentum eigenstates of a relativistic spin– 1 2 particle may behave non- trivially. For example, a particle with its angular momentum initially polarized in the direction of propagation may acquire a nonzero component of angular momentum in the opposite direction on turning through 2π radians. Also, the usual nonrelativistic effective potential acquires an additional factor in the relativistic theory.
Reliability in missile and space operations

Three crucial factors in missile reliability are design, component quality and human error, with special emphasis on component quality. Success in our missile effort will not be achieved unless there are orders of magnitude improvement in parts reliability.
Isolation of a phytoalexin, trans-p-coumaryl aldehyde, from Cucurbita maxima, Cucurbitaceae

An induced antifungal compound, trans-p-coumaryl aldehyde, was isolated from fruit tissue of Cucurbita maxima which had been elicited with pectinase. Its chemical structure was identified by NMR and MS. This is the first report of a phytoalexin from a member of the Cucurbitaceae.
Environmental Dependence of the Fundamental Plane of Galaxy Clusters.

Galaxy clusters approximate a planar distribution in a three-dimensional parameter space that can be characterized, for example, by an optical luminosity, half-light radius, and X-ray luminosity. We find the nearest neighbor clusters for those common to either of two previous fundamental-plane studies and a high-quality cluster redshift catalog. Examining scatter about one plane in parameter space, we find a 2 σ result that it is dependent on the nearest neighbor distance. Study of another sample of X-ray clusters shows that those with high central gas densities are systematically (2.5 σ) closer to neighbor clusters. These results suggest a possible explanation for recent evidence that X-ray cooling flow clusters reside in crowded environments.
Problems in the analysis of gamma-ray burst spectra

Abstract Spectral measurements by the Solar Maximum Mission have been used to confirm the cyclotron lines in gamma-ray bursts reported from the Konus experiment. We present ISEE-3 data for the same burst (GB800419) during the same period of time which show no line. We discuss various problems in the analysis of scintillator spectra and point out that unfolded spectra are not necessarily unique and that the position of a data point in a deconvolved spectrum may vary depending on the assumed overall shape of the spectrum. As a result, if the analysis assumes a soft spectrum (such as optically thin thermal bremsstrahlung) an absorption feature might appear, whereas a harder spectrum (such as a Comptonized blackbody) would not require the feature. Since the continuum shape probably changes during the duration of a typical burst, the nonuniqueness of the spectral unfolding, combined with the assumption that the continuum is optically thin thermal bremsstrahlung, could give rise to spurious “absorption” features which vary on a time scale of seconds. Despite these problems, there is still some evidence for narrow spectral lines in the range 45 to 65 keV but not for the broad lines reported from the Konus experiment. Unfortunately, the range 45 to 65 keV is the most difficult spectral region to unfold.
Monolithic silica liquid chromatography columns for the determination of cyclooxygenase II inhibitors in human plasma.

Abstract Methods employing monolithic HPLC columns for the determination of the cyclooxygenase II inhibitors rofecoxib (I) and 3-isopropoxy-4-(4-methanesulfonylphenyl)-5,5′-dimethyl-5H-furan-2-one (DFP, III) in human plasma are described. Each analyte, together with an internal standard was extracted from the plasma matrix using solid-phase extraction in the 96-well format. The analytes were chromatographed on a Chromolith Speed Rod monolithic HPLC column (4.6×50 mm). Analyte detection for rofecoxib was via fluorescence following post-column photochemical derivatization. Detection for III was based on the native fluorescence of the compound. The precision, accuracy, and linearity of the methods were found to be comparable to those obtained using methods employing conventional packed HPLC columns. Use of the monolithic column permitted mobile phase flow-rates of up to 6.5 ml/min to be employed in the assays. The use of elevated flow-rates enabled the per sample analysis time to be reduced by up to a factor of 5 compared with assays based on packed HPLC columns. The results of experiments aimed at evaluating the ruggedness and reproducibility of monolithic columns employed in bioanalytical methods are presented.
The neural decoding toolbox

Population decoding is a powerful way to analyze neural data, however currently only a small percentage of systems neuroscience researchers use this method. In order to increase the use of population decoding, we have created the Neural Decoding Toolbox (NDT) which is a Matlab package that makes it easy to apply population decoding analyses to neural activity. The design of the toolbox revolves around four abstract object classes which enables users to interchange particular modules in order to try different analyses while keeping the rest of the processing stream intact. The toolbox is capable of analyzing data from many different types of recording modalities, and we give examples of how it can be used to decode basic visual information from neural spiking activity and how it can be used to examine how invariant the activity of a neural population is to stimulus transformations. Overall this toolbox will make it much easier for neuroscientists to apply population decoding analyses to their data, which should help increase the pace of discovery in neuroscience.
On Overlays and Minimization Diagrams

The overlay of 2≤m≤d minimization diagrams of n surfaces in ℝ d is isomorphic to a substructure of a suitably constructed minimization diagram of mn surfaces in ℝ d+m−1. This elementary observation leads to a new bound on the complexity of the overlay of minimization diagrams of collections of d-variate semi-algebraic surfaces, a tight bound on the complexity of the overlay of minimization diagrams of collections of hyperplanes, and faster algorithms for constructing such overlays. Further algorithmic implications are discussed.
A Theory of Financing Constraints and Firm Dynamics

There is widespread evidence supporting the conjecture that borrowing constraints have important implications for firm growth and survival. In this paper we model a multiperiod borrowing/lending relationship with asymmetric information. We show that borrowing constraints emerge as a feature of the optimal long-term lending contract, and that such constraints relax as the value of the borrower's claim to future cash flows increases. We also show that the optimal contract has interesting implications for firm dynamics. In agreement with the empirical evidence, as age and size increase, mean and variance of growth decrease, and firm survival increases.
Kinetics of hydroxyl radical reactions with formaldehyde and 1,3,5‐trioxane between 290 and 600 K

Absolute rate constants are measured for the reactions: OH + CH2O, over the temperature range 296–576 K and for OH + 1,3,5-trioxane over the range 292–597 K. The technique employed is laser photolysis of H2O2 or HNO3 to produce OH, and laser-induced fluorescence to directly monitor the relative OH concentration. The results fit the following Arrhenius equations: k (CH2O) = (1.66 ± 0.20) × 10−11 exp[−(170 ± 80)/RT] cm3 s−1 and k(1,3,5-trioxane) = (1.36 ± 0.20) × 10−11 exp[−(460 ± 100)/RT] cm3 s−1. The transition-state theory is employed to model the OH + CH2O reaction and extrapolate into the combustion regime. The calculated result covering 300 to 2500 K can be represented by the equation: k(CH2O) = 1.2 × 10−18T2.46 exp(970/RT) cm3 s−1. An estimate of 91 ± 2 kcal/mol is obtained for the first CH bond in 1,3,5-trioxane by using a correlation of CH bond strength with measured activation energies.
The Human Genome Project: Prospects and Implications for Clinical Medicine

The recently initiated human genome project is a large international effort to elucidate the genetic architecture of the genomes of man and several model organisms. The initial phases of this endeavor involve the establishment of rough blueprints (maps) of the genetic landscape of these genomes, with the long-term goal of determining their precise nucleotide sequences and identifying the genes. The knowledge gained by these studies will provide a vital tool for the study of many biologic processes and will have a profound impact on clinical medicine.
The vertical structure and thickness of Saturn's rings

The steady state thickness and vertical structure of Saturn's rings are discussed with regard to whether a collapse to a monolayer due to particle collisions may be prevented by various mechanisms. The differences between thick rings and wavy monolayers are outlined and used to show that such coherent perturbations to the rings as satellite and solar gravitational effects would produce a wavy monolayer while such dispersive mechanisms as meteoroid impact, radiation pressure, Kepler shear and radial spreading, which would produce the random particle motions necessary to maintain a thick layer, are probably insignificant. Given a typical power law distribution of particle sizes, it is found that gravitational scattering of small particles by large ones would maintain a ring thickness of several times the radius of the largest particles. A steady state ring thickness of 20 to 50 meters, derived from energy considerations, would imply a maximum particle size of a few meters.
Estimating the profits from trading strategies

Price improvement is the difference between the execution price of an order and the quoted bid or ask when the order was submitted. We show that expected price improvement falls off dramatically as the size of the order approaches the quoted depth, and becomes negative for larger orders. This is particularly important for small firms because the quoted depths are low. Using quoted spreads and depths and our estimate of expected price improvement, we show that trading strategies that attempt to exploit the weekly predictability of small-firm returns would be swamped by transaction costs. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Oxidative cyclizations of allenic aldehydes

Abstract Allenyl aldehydes and ketones are oxidatively cyclized by dimethyldioxirane to provide cyclic acetals and hemiacetals.
Comparing and Calibrating Black Hole Mass Estimators for Distant Active Galactic Nuclei

Black hole mass (MBH) is a fundamental property of active galactic nuclei (AGNs). In the distant universe, MBHis commonly estimated using the Mg II, Hβ, or Hα emission line widths and the optical/UV continuum or line luminosities as proxies for the characteristic velocity and size of the broad-line region. Although they all have a common calibration in the local universe, a number of different recipes are currently used in the literature. It is important to verify the relative accuracy and consistency of the recipes, as systematic changes could mimic evolutionary trends when comparing various samples. At z = 0.36, all three lines can be observed at optical wavelengths, providing a unique opportunity to compare different empirical recipes. We use spectra from the Keck Telescope and the Sloan Digital Sky Survey to compare MBHestimators for a sample of 19 AGNs at this redshift. We compare popular recipes available from the literature, finding that MBHestimates can differ up to 0.38 ± 0.05 dex in the mean (or 0.13 ± 0.05 dex, if the same virial coefficient is adopted). Finally, we provide a set of 30 internally self-consistent recipes for determining MBHfrom a variety of observables. The intrinsic scatter between cross-calibrated recipes is in the range 0.1-0.3 dex. This should be considered as a lower limit to the uncertainty of the MBHestimators. © 2008. The American Astronomical Society. All rights reserved.
Interferometric Density Measurements in the Arc of a Pulsed Plasma Thruster

Abstract : Spatial and temporal measurements of the electron density were made using a He-Ne laser. The multiple pass Mach-Zehnder interferometer detects densities above ten to the fifteenth power particles/cubic centimerers. Using these data and free streaming solutions to the Boltzmann equation, which model the expansion of the exhaust, we determine the ion temperature and total charge in the exhaust. The percentage ionization can than be found, and estimates made of the gas dynamic portion of the thrust.
A Generalization of Moufang and Steiner Loops

We study a variety of loops, RIF, which arise naturally from considering inner mapping groups, and a somewhat larger variety, ARIF. All Steiner and Moufang loops are RIF, and all flexible C-loops are ARIF. All ARIF loops are diassociative.
Role of kinetic inductance in transport properties of shunted superconducting nanowires

Recently, transport measurements have been carried out in resistively shunted long superconducting nanowires (Brenner et?al 2012 Phys. Rev. B 85 224507). The measured voltage?current (V?I) characteristics were explained by the appearance of the phase slip centers in the shunted wire, and the whole wire was modeled as a single Josephson junction. The kinetic inductance of the long nanowires used in experiments is generally large. Here we argue that the shunted superconducting nanowire acts as a Josephson junction in series with an inductor. The inductance depends on the length and the cross section of the wire. The inclusion of inductance in our analysis modifies the V?I curves, and increases the rate of switching from the superconducting state to the resistive state. The quantitative differences can be quite large in some practical parameter sets, and might be important to properly understand the experimental results. Our proposed model can be verified experimentally by studying the shunted superconducting nanowires of different lengths and cross sections.
The structure of dark matter halos in an annihilating dark matter model

The inability of standard non-interacting cold dark matter (CDM) to account for the small scale structure of individual galaxies has led to the suggestion that the dark matter may undergo elastic and/or inelastic scattering. We simulate the evolution of an isolated dark matter halo which undergoes both scattering and annihilation. Annihilations produce a core that grows with time due to adiabatic expansion of the core as the relativistic annihilation products flow out of the core, lessening the binding energy. An effective annihilation cross section per unit mass equal to 0.03 cm2 g−1 (100 km s−1/v) with a scattering cross section per unit mass of 0.6 cm g−1 produces a 3 kpc core in a 1010 M⊙ halo that persists for 100 dynamical times. The same cross section leads to a core of only 120 pc in a rich cluster. In addition to creating to cores, annihilation should erase structure on scales below ∼3×108 M⊙. Annihilating dark matter provides a mechanism for solving some of the problems of non-interacting CDM, at the expense of introducing a contrived particle physics model.
Total Synthesis of Reblastatin

Enantioselective total synthesis of reblastatin is described. The synthesis highlights hydrozirconation, transmetalation, aldehyde addition sequence to install E-trisubstituted olefin and C7 stereocenter, and the first use of an intramolecular Buchwald-like amidation reaction to close the 19-membered macrolactam.
The Far-Infrared Spectral Energy Distributions of Quasars

The origin of the infrared emission in Active Galactic Nuclei (AGN), whose strength is comparable to the optical/ultraviolet (OUV) emission, is generally thought to be a combination of thermal emission from dust and non-thermal, synchrotron emission. Although data are sparse, particularly in the far-infrared, the broad wavelength range of this emission suggests a wide range of temperatures and a combination of AGN and starburst heating mechanisms. The strength of the non-thermal emission is expected to be related to the radio emission. While this scenario is well-established, basic questions, such as the spatial and temperature distribution of the dust, the relative importance of AGN and starburst heating, and the significance of the non-thermal contribution remain largely undetermined. The wide wavelength range of the Infrared Space Observatory (ISO) combined with its arcmin spatial resolution and increased sensitivity facilitated the observation of a larger subset of the AGN population than previously covered, allowing these questions to be investigated in more detail. This paper will review the spectral energy distributions (SED) of AGN with particular emphasis on the infrared emission and on ISO's contributions to our knowledge. Preliminary results from ISO observations of X-ray selected and high-redshift AGN will be described.
Total variation approximations and conditional limit theorems for multivariate regularly varying random walks conditioned on ruin

We study a new technique for the asymptotic analysis of heavy-tailed systems conditioned on large deviations events. We illustrate our approach in the context of ruin events of multidimensional regularly varying random walks. Our approach is to study the Markov process described by the random walk conditioned on hitting a rare target set. We construct a Markov chain whose transition kernel can be evaluated directly from the increment distribution of the associated random walk. This process is shown to approximate the conditional process of interest in total variation. Then, by analyzing the approximating process, we are able to obtain asymptotic conditional joint distributions and a conditional functional central limit theorem of several objects such as the time until ruin, the whole random walk prior to ruin, and the overshoot on the target set. These types of joint conditional limit theorems have been obtained previously in the literature only in the one dimensional case. In addition to using different techniques, our results include features that are qualitatively different from the one dimensional case. For instance, the asymptotic conditional law of the time to ruin is no longer purely Pareto as in the multidimensional case.
Active control of propeller-induced noise fields inside a flexible cylinder

An active noise control model has been evaluated for reducing aircraft interior noise. The structural noise transmission properties of an aircraft fuselage were modelled as a flexible cylinder excited by external acoustic dipoles simulating the noise produced by twin propellers. The amplitudes of an internal distribution of monopole control sources were determined such that the area-weighted mean square acoustic pressure was minimized in the propeller plane. The noise control model was evaluated at low frequencies corresponding to the blade passage frequency and first few harmonics of a typical turbo-prop aircraft. Interior noise reductions of 20 25 dB were achieved, over a substantial region of the cylindrical cross-section, with just a few monopole control sources. The most favorable interior noise reductions were achieved when the active noise control model was used in combination with propeller source phasing.
An Effective Carathéodory Theorem

By means of the property of effective local connectivity, the computability of finding the Caratheodory extension of a conformal map of a Jordan domain onto the unit disk is demonstrated.
Redefining Individual Growth and Development Indicators Phonological Awareness

Learning to read is one of the most important indicators of academic achievement. The development of early literacy skills during the preschool years is associated with improved reading outcomes in later grades. One of these skill areas, phonological awareness, shows particular importance because of its strong link to later reading success. Presented here are two studies that describe the development and revision of four measures of phonological awareness skills: Individual Growth and Development Indicators Sound Blending, Syllable Sameness, Rhyming, and Alliteration 2.0. The authors discuss the measure development process, revision, and utility within an early childhood Response to Intervention framework.
Elevated-temperature ``ultra`` fast fracture strength of advanced ceramics: An approach to elevated-temperature ``inert`` strength

The determination of "ultra" fast fracture strengths of five silicon nitride ceramics at elevated temperatures has been made by using constant stress-rate ("dynamic fatigue") testing with a series of "ultra" fast test rates. The test material included four monolithic and one SiC whisker-reinforced composite silicon nitrides. Of the five test materials, four silicon nitrides exhibited the elevated -temperature strengths that approaches their respective room-temperature strengths at an "ultra" fast test rate of 3.3 x 10(exp 4) MPa/s. This implies that slow cracks growth responsible for elevated-temperature failure can be eliminated or minimized by using the "ultra" fast test rate. These ongoing experimental results have shed light on laying a theoretical and practical foundation on the concept and definition of elevated-temperature "inert" strength behavior of advanced ceramics.
On a Singular Limit Problem for Nonlinear Maxwell's Equations

In this paper we study the following nonlinear Maxwell's equations, eEt+σ(x, |E|) E=∇×H+F, Ht+∇×E=0, where σ(x, s) is a monotone graph of s. It is shown that the system has a unique weak solution. Moreover, the limit of the solution as e→0 converges to the solution of quasi-stationary Maxwell's equations.
Convex Models of Distribution System Reconfiguration

We derive new mixed-integer quadratic, quadratically constrained, and second-order cone programming models of distribution system reconfiguration, which are to date the first formulations of the ac problem that have convex, continuous relaxations. Each model can be reliably and efficiently solved to optimality using standard commercial software. In the course of deriving each model, we obtain original quadratically constrained and second-order cone approximations to power flow in radial networks.
The bend stiffness of S-DNA

We formulate and solve a two-state model for the elasticity of nicked, double-stranded DNA that borrows features from both the Worm Like Chain and the Bragg-Zimm model. Our model is computationally simple, and gives an excellent fit to recent experimental data through the entire overstretching transition. The fit gives the first value for the bending stiffness of the overstretched state as about 12 nmkBT, a value quite different from either B-form or single-stranded DNA.
Applications of Microlensing to Stellar Astrophysics

Over the past decade, microlensing has developed into a powerful tool to study stellar astrophysics, especially stellar atmospheres, stellar masses, and binarity. I review this progress. Stellar atmospheres can be probed whenever the source in a microlensing event passes over the caustic (contour of infinite magnification) induced by the lens because the caustic effectively resolves the source. Broadband observations of four events have yielded limb-darkening measurements, which in essence map the atmospheric temperature as a function of depth. And now, for the first time, spectroscopic observations of one event promise much richer diagnostics of the source atmosphere. In the past 2 years, a practical method has finally been developed to systematically measure the lens masses in microlensing events. This will permit a census of all massive objects, both dark and luminous, in the Galactic bulge, including low-mass stars, brown dwarfs, white dwarfs, neutron stars, and black holes. The method combines traditional ground-based photometry with astrometric and photometric measurements by the Space Interferometry Mission (SIM) in solar orbit. Using a related technique, SIM can also obtain accurate (1%) mass measurement of a dozen or so nearby stars, thus enabling precision tests of stellar models. Binary lenses can give rise to dramatic and easily detectable microlensing signatures, even for large mass ratios. This makes microlensing a potentially powerful probe of the companion mass distribution, especially in the Galactic bulge, where this function is difficult to probe by other techniques.
Descent Identities, Hessenberg Varieties, and the Weil Conjectures

We apply the Weil conjectures to the Hessenberg varieties to obtain information about the combinatorics of descents in the symmetric group. Combining this with elementary linear algebra leads to elegant proofs of some identities from the theory of descents.