cssi/SciSciGPT-SciSciNet huggingface dataset:
Credit ratings and IPO pricing

Abstract We examine the effects of credit ratings on IPO pricing. The evidence from U.S. common share IPOs during 1986–2004 shows that when firms go public, those with credit ratings are underpriced significantly less than firms without credit ratings. Credit rating levels, however, do not have a significant effect on IPO underpricing. The existence of credit rating reduces uncertainty about firm value. It is the value certainty that matters, not the value per se. Credit ratings also reduce the degree of price revision during the bookbuilding process and the aftermarket volatility in the post-IPO period. The evidence suggests that credit ratings convey useful information in reducing value uncertainty of the issuing firms as well as information asymmetry in the IPO markets.
Quantum Monte Carlo calculations for light nuclei

Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 30 different (j{sup {prime}}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.
Ion pair potentials-of-mean-force in water

Motivated by the surprising dielectric model predictions of alkali-halide ion pair potentials-of-mean-force in water due to Rashin, we reanalyze the theoretical bases of that comparison. We discuss recent, pertinent molecular simulation and integral equation results that have appeared for these systems. We implement dielectric model calculations to check the basic features of Rashin's calculations. We confirfn that the characteristic structure of contact and solvent-separated minima does appear in the dielectric model results for the pair potentials-of-mean-force for oppositely charged ions in water under physiological thermodynamic conditions. Comparison of the dielectric model results with the most current molecular level information indicates that the dielectric model does not, however, provide an accurate description of these potentials-of-mean-force. Since literature results indicate that dielectric models can be helpfully accurate on a coarse, or chemical energy scale, we consider how they might be based more firmly on molecular theory. The objective is a parameterization better controlled by molecular principles and thus better adapted to the prediction of quantities of physical interest. Such a result might be expected to describe better the thermal-level energy changes associated with simple molecular rearrangements, i.e. ion pair potentials-of-mean-force. We note that linear dielectric models correspond to modelistic implementations of second-order thermodynamic perturbation theory for the excess chemical potential of a distinguished solute molecule at infinite dilution. Therefore, the molecular theory corresponding to the dielectric models is second-order thermodynamic perturbation theory for that excess chemical potential. Examination of the required formulae indicate that this corresponding molecular theory should be quite amenable to computational implementation. The second-order, or fluctuation, term raises a technical computational issue of treatment of long-ranged interactions similar to the one which arises in calculation of the dielectric constant of the solvent. Satisfactory calculation of that term will require additional theoretical consideration of those issues. It is contended that the most important step for further development of dielectric models would be a separate assessment of the first-order perturbative term (equivalently thepotential at zero charge) which vanishes in the dielectric models but is generally nonzero. Parameterization of radii and molecular volumes should then be based on the second-order perturbative term alone. Illustrative initial calculations are presented and discussed.
The role of mortality in the transmission of knowledge

We investigate, both theoretically and quantitatively, a previously unexplored link between gains in adult mortality and productivity growth. Our mechanism allocates a central role to individuals as carriers of useful ideas and to personal contact as an important means of transferring these ideas. It thus implies that disrupting a human life impedes the process of knowledge transmission across time. We derive a simple and intuitive form of the dependence of aggregate knowledge transfer on adult mortality and incorporate it into a model of endogenous growth. We then quantitatively examine the relevance of the proposed link in application to the long-run growth experience of England. Our calibration exercise suggests that the reduction in adult mortality, by improving knowledge transmission across time and encouraging more innovation, was a quantitatively important force behind the takeoff in output per capita.
A Class of Efficient Contention Resolution Algorithms for Multiple Access Channels

A discrete time multiaccess channel is considered where the outcome of a transmission is either "idle," "success," or "collision," depending on the number of users transmitting simultaneously. Messages involved in a "collision" must be retransmitted. An efficient access allocation policy is developed for the case where infinitely many sources generate traffic in a Poisson manner and can all observe the outcomes of the previous transmissions. Its rate of success is 0.48776. Modifications are presented for the cases where the transmission times depend on the transmission outcomes and where observations are noisy.
Constructing cell data for diagram algebras

Abstract We show how the treatment of cellularity in families of algebras arising from diagram calculi, such as Jones’ Temperley–Lieb wreaths, variants on Brauer’s centralizer algebras, and the contour algebras of Cox et al. (of which many algebras are special cases), may be unified using the theory of tabular algebras. This improves an earlier result of the first author (whose hypotheses covered only the Brauer algebra from among these families).
Broad Beam Ion Source Operation with Four Common Gases.

A Kaufman-type broad beam ion source, used for sputtering and etching purposes, has been operated with Ar, Kr, O2 and N2 gas inputs over a wide range of beam energies (200-1200 eV) and gas flow rates (1-10 sccm). The maximum ion beam current density for each gas saturates at about 2.5 mA/sq cm as gas flow is increased. The discharge threshold voltage necessary to produce a beam and the beam efficiency (beam current/molecular current), however, varied considerably. Kr had the lowest threshold and highest efficiency, Ar next, then N2 and O2. The ion beam current varied only weakly with beam energy for low gas flow rates, but showed a factor of two increase when the gas flow was higher.
Toxicity of imidazolium ionic liquids to freshwater algae

Room-temperature ionic liquids (ILs) are a class of novel green chemicals being designed to replace traditional volatile organic solvents in industrial processes. The potential effects of ILs on aquatic ecosystems have been poorly studied, despite the possibility of unintentional discharge into rivers and lakes, and their intentional disposal in wastewater treatment plants. We studied the effects of three imidazolium ionic liquids, 1-butyl-, 1-hexyl- and 1-octyl-3-methylimidazolium bromide, on the growth rates of two freshwater algae, Scenedesmus quadricauda and Chlamydomonas reinhardtii, in 96 h standard toxicity bioassays. Increases in alkyl chain length increased the toxicity of these ionic liquids to both S. quadricauda (EC50 values of 0.005–13.23 mg L–1) and C. reinhardtii (EC50 values of 4.07–2138 mg L–1). Bioassays were performed in both nutrient-amended media and low-nutrient groundwater to evaluate if test conditions altered IL toxicity. EC50 values for S. quadricauda were similar between nutrient media and groundwater for all ILs tested, while the presence of nutrient media appeared to partially mitigate the toxicity of ILs to C. reinhardtii (groundwater EC50 < media EC50). Overall, S. quadricauda was much more sensitive than C. reinhardtii to all ILs tested, perhaps reflecting differences in cell wall structure. EC50 values suggest that ILs are more, or just as, toxic to algae than many of the solvents they are intended to replace. Results of this study show that ionic liquids can elicit a range of algal responses, suggesting that a diversity of target organisms be tested in order to predict the effects of ILs in natural environments.
Connecting past and present climate variability to the water levels of Lakes Michigan and Huron.

[1] The water levels of Lakes Michigan and Huron have been monitored since 1865, and numerous attempts have since been made to connect their variations to potentially predictable large-scale climate modes. In the present study, the levels are analyzed after outflow-related damping effects were removed, increasing the transparency of the lake level fluctuations and potential climate connections. This filtering exposes a large oscillation which is connected to the Atlantic Multidecadal Oscillation (AMO), and a ∼27-yr periodicity that is likely resulting from the intermodulation of two near-decadal cycles originating in the North Atlantic region. While the lake level fluctuations prior to 1980 were predominately driven by changes in precipitation, it is now found that for the first time in our years of record, evaporation has begun to significantly contribute to lake level changes. Summertime evaporation rates have more than doubled since 1980 as a result of increasing water-surface temperatures, which are significantly correlated with decreasing wintertime ice cover.
Regulation of atmospheric oxygen during the Proterozoic

Abstract Many studies suggest that oxygen has remained near modern levels throughout the Phanerozoic, but was much less abundant from the “Great Oxygenation Event” around 2.4 Ga until the late Neoproterozoic around 600 Ma ( Kump, 2008 ). Using a simple model, we show that the maintenance of atmospheric pO2 at ∼1% of present atmospheric levels (PAL) is inconsistent with modern biogeochemical cycling of carbon, sulfur and iron unless new feedbacks are included. Low oxygen conditions are stable in our model if the flux of phosphorus to the oceans was greatly reduced during the Proterozoic. We propose a mechanism to reduce this flux through the scavenging of phosphate ions with an “iron trap” driven by greater surface mobility of ferrous iron in a low pO2 world. Incorporating this feedback leads to two stable equilibria for atmospheric oxygen, the first quantitative hypothesis to explain both Proterozoic and Phanerozoic O2 concentrations.
Arterial sodium content in experimental congestive heart failure.

This study sought to determine whether the electrolyte content of peripheral arteries is altered in experimental congestive heart failure (CHF) and whether such change, if present, would help to explain the abnormal vascular stiffness seen in human CHF. The concentrations of sodium (Na+) and potassium (K+) were determined in samples of aorta (Ao) and femoral arterial branches (FA) of 17 dogs. Six had ascites due to CHF produced by rapid ventricular pacing (left ventricular end-diastolic pressure [LVEDP] 26.2 mm Hg and maximal velocity of myocardial shortening [Vmax] 2.39 circumferences/sec). In the 11 animals in the control group pacing was stopped prior to the onset of CHF or the animals were not paced (LVEDP, 8.8 mm Hg and Vmax, 2.98 circumferences/sec). In CHF, mean Ao Na+ was 38.0 ± 2.3 mEq/100 g dry weight and FA Na+ was 44.2 ± 3.2 mEq/100 g. These were significantly higher than similar samples taken from the 11 normal dogs (Na+, 31.9 ± 1.6 [P < 0.05] and 31.9 ± 1.8 [P < 0.01] mEq/100 g, respectively...
Microwave spectrum and conformation of vinyl fluoroformate

Abstract The microwave spectrum of vinyl fluoroformate displays strong R branch a -type transitions from a planar syn-anti conformer with rotational constants, A 0 = 309(1) MHz, B 0 = 2277.113(6) MHz, and C 0 = 1866.873(6) MHz. Five satellites attributed to successively excited states of the O-vinyl (τ 2 (COCC)) torsion have been assigned. Their inertial defects are consistent with a vibrational frequency of 63 cm −1 indicating that the internal rotation barrier about the O-vinyl bond is at least 640 cm −1 . Two vibrational satellites attributed to the O-fluoroformyl (τ 1 (OCOC)) torsion have been assigned. Their inertial defects are consistent with a torsional frequency of 104 cm −1 which is compatible with an internal rotation barrier about the O-fluoroformyl bond of at least 1675 cm −1 . An extensive search for rotational transitions of other conformers, particularly the syn-syn conformer was not successful. Based on the spectral signal/noise ratio of the observed transitions it is estimated that all other conformers must be at least 350 cm −1 higher in energy than the syn-syn conformer.
Developmental outcomes of very preterm infants with tracheostomies

Objectives To evaluate the neurodevelopmental outcomes of very preterm ( Study design Retrospective cohort study from 16 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network over 10 years (2001-2011). Infants who survived to at least 36 weeks (N = 8683), including 304 infants with tracheostomies, were studied. Primary outcome was death or neurodevelopmental impairment (NDI; a composite of ≥1 of developmental delay, neurologic impairment, profound hearing loss, severe visual impairment) at a corrected age of 18-22 months. Outcomes were compared using multiple logistic regression. We assessed the impact of timing by comparing outcomes of infants who underwent tracheostomy before and after 120 days of life. Results Tracheostomies were associated with all neonatal morbidities examined and with most adverse neurodevelopmental outcomes. Death or NDI occurred in 83% of infants with tracheostomies and 40% of those without (OR adjusted for center 7.0, 95% CI 5.2-9.5). After adjustment for potential confounders, odds of death or NDI remained higher (OR 3.3, 95% CI 2.4-4.6), but odds of death alone were lower (OR 0.4, 95% CI 0.3-0.7) among infants with tracheostomies. Death or NDI was lower in infants who received their tracheostomies before, rather than after, 120 days of life (aOR 0.5, 95% CI 0.3-0.9). Conclusions Tracheostomy in preterm infants is associated with adverse developmental outcomes and cannot mitigate the significant risk associated with many complications of prematurity. These data may inform counseling about tracheostomy in this vulnerable population.
Structures, energetics and spectroscopy of gas phase transition metal ion–benzene complexes

Abstract Metal–benzene complexes provide classic examples of organometallic chemistry, and their ions have similar appeal for mass spectrometry and ion chemistry. This review covers new formation methods for the generation of novel metal ion–benzene complexes and clusters in the gas phase, as well as new measurements of their properties. Collision induced dissociation, radiative decay kinetics and photodissociation methods have been applied to determine bonding energetics, while UV–vis, infrared and photoelectron spectroscopic measurements have been applied to determine structure and bonding patterns. Electronic structure calculations have been pursued to complement these various experiments. This review surveys recent progress in these areas, providing an overview of the field and suggesting future research directions.
Exact solutions of anisotropic diffusion-limited reactions with coagulation and annihilation

We report exact results for one-dimensional reaction-diffusion modelsA+A→inert,A+A→A, andA+B→inert, where in the latter case like particles coagulate on encounters and move as clusters. Our study emphasizes anisotropy of hopping rates; no changes in universal properties are found, due to anisotropy, in all three reactions. The method of solution employs mapping onto a model of coagulating positive integer charges. The dynamical rules are synchronous, cellular-automaton type. All the asymptotic large-time results for particle densities are consistent, in the framework of universality, with other model results with different dynamical rules, when available in the literature.
Time-marching transonic flutter solutions including angle-of-attack effects

Transonic aeroelastic solutions based upon the transonic small perturbation potential equation were studied. Time-marching transient solutions of plunging and pitching airfoils were analyzed using a complex exponential modal identification technique, and seven alternative integration techniques for the structural equations were evaluated. The HYTRAN2 code was used to determine transonic flutter boundaries versus Mach number and angle-of-attack for NACA 64A010 and MBB A-3 airfoils. In the code, a monotone differencing method, which eliminates leading edge expansion shocks, is used to solve the potential equation. When the effect of static pitching moment upon the angle-of-attack is included, the MBB A-3 airfoil can have multiple flutter speeds at a given Mach number.
Automated detection of semagram-laden images using adaptive neural networks

Digital steganography has been used extensively for electronic copyright stamping, but also for criminal or covert activities. While a variety of techniques exist for detecting steganography the identification of semagrams, messages transmitted visually in a non-textual format remain elusive. The work that will be presented describes the creation of a novel application which uses hierarchical neural network architectures to detect the likely presence of a semagram message in an image. The application was used to detect semagrams containing Morse Code messages with over 80% accuracy. These preliminary results indicate a significant advance in the detection of complex semagram patterns.
Cross-coupling reactions of aryl pivalates with boronic acids.

The first cross-coupling of acylated phenol derivatives has been achieved. In the presence of an air-stable Ni(II) complex, readily accessible aryl pivalates participate in the Suzuki−Miyaura coupling with arylboronic acids. The process is tolerant of considerable variation in each of the cross-coupling components. In addition, a one-pot acylation/cross-coupling sequence has been developed. The potential to utilize an aryl pivalate as a directing group has also been demonstrated, along with the ability to sequentially cross-couple an aryl bromide followed by an aryl pivalate, using palladium and nickel catalysis, respectively.
Accurate Navier-Stokes results for the hypersonic flow over a spherical nosetip

The unsteady, thin-layer Navier-Stokes equations for a perfect gas are solved with a linearized block, alternating direction implicit finite-difference solution procedure. Solution errors due to numerical dissipation added to the governing equations are evaluated. Errors in the numerical predictions on three-differe nt grids are determined where Richardson extrapolation is used to estimate the exact solution. Accurate computational results are tabulated for the hypersonic laminar flow over a spherical body, which can be used as a benchmark test case. Predictions obtained from the code are in good agreement with inviscid numerical results and experimental data.
Liquid−Liquid Equilibria of the Benzene + Water + Acetic Acid Ternary System and Solubility of Benzene in Water: Effect of Calcium Chloride

The aqueous solubility of benzene in the presence of calcium chloride at different concentrations was measured at 303.15 K. Also, experimental liquid−liquid equilibrium data were obtained at 303.15 K for the ternary system benzene + water + acetic acid as a function of calcium chloride concentration. The solubility of benzene in water is 1910 ppm at 303.15 K and decreases to 502 ppm with the addition of 20 mass % calcium chloride. The solubility data of benzene in calcium chloride solutions were correlated with the Setschenow equation, and the Setschenow constant, ks, is 0.33 ± 0.002. From the liquid−liquid equilibrium studies it is observed that the amount of acetic acid extracted to the organic phase increases with the amount of added calcium chloride. It is suggested that the salt effect should be explored further to develop or improve processes to treat waste streams contaminated with organic compounds.
Density, Overcompleteness, and Localization of Frames. I. Theory

Frames have applications in numerous fields of mathematics and engineering. The fundamental property of frames which makes them so useful is their overcompleteness. In most applications, it is this overcompleteness that is exploited to yield a decomposition that is more stable, more robust, or more compact than is possible using nonredundant systems. This work presents a quantitative framework for describing the overcompleteness of frames. It introduces notions of localization and approximation between two frames \({\frak F} = \{f_i\}_{i\in I}\) and \({\frak E} = \{e_j\}_{j\in G}\) (\(G\) a discrete abelian group), relating the decay of the expansion of the elements of \({\frak F}\) in terms of the elements of \({\frak E}\) via a map \(a : I \rightarrow G\). A fundamental set of equalities are shown between three seemingly unrelated quantities: The relative measure of \({\frak F}\), the relative measure of \({\frak E}\) — both of which are determined by certain averages of inner products of frame elements with their corresponding dual frame elements — and the density of the set \(a(I)\) in \(G\). Fundamental new results are obtained on the excess and overcompleteness of frames, on the relationship between frame bounds and density, and on the structure of the dual frame of a localized frame. In a subsequent article, these results are applied to the case of Gabor frames, producing an array of new results as well as clarifying the meaning of existing results. The notion of localization and related approximation properties introduced in this article are a spectrum of ideas that quantify the degree to which elements of one frame can be approximated by elements of another frame. A comprehensive examination of the interrelations among these localization and approximation concepts is presented.
An enantioselective total synthesis of (+)-geissoschizine.

A concise asymmetric synthesis of the indole alkaloid (+)-geissoschizine (1) has been completed. The synthesis features the highly diastereoselective vinylogous Mannich reaction of 3 with 4 to give 5, which is elaborated into the key tetracyclic intermediate 7 in two steps. Following the stereoselective introduction of the ethylidene moiety to give 9, reduction of the lactam and radical decarboxylation via an acyl selenide gave 12, which was converted into (+)-geissoschizine by formylation. The synthesis requires only 11 chemical operations and proceeds in an overall yield of 17%.
Phase transfer catalyzed oxidation of alcohols with sodium hypochlorite

Abstract Phase transfer catalyzed oxidation of alcohols with sodium hypochlorite in ethyl acetate media resulted in good to excellent yield of oxidized products. These reactions are mild, efficient, and safe. The experimental procedures and work-ups are very convenient.
Tuning structure and mobility of solvation shells surrounding tracer additives.

Molecular dynamics simulations and a stochastic Fokker-Planck equation based approach are used to illuminate how position-dependent solvent mobility near one or more tracer particle(s) is affected when tracer-solvent interactions are rationally modified to affect corresponding solvation structure. For tracers in a dense hard-sphere fluid, we compare two types of tracer-solvent interactions: (1) a hard-sphere-like interaction, and (2) a soft repulsion extending beyond the hard core designed via statistical mechanical theory to enhance tracer mobility at infinite dilution by suppressing coordination-shell structure [Carmer et al., Soft Matter 8, 4083–4089 (2012)]. For the latter case, we show that the mobility of surrounding solvent particles is also increased by addition of the soft repulsive interaction, which helps to rationalize the mechanism underlying the tracer’s enhanced diffusivity. However, if multiple tracer surfaces are in closer proximity (as at higher tracer concentrations), similar interactions that disrupt local solvation structure instead suppress the position-dependent solvent dynamics.
Total Synthesis of (−)-Bafilomycin A1

A highly stereoselective total synthesis of (-)-bafilomycin A(1), the naturally occurring enantiomer of this potent vacuolar ATPase inhibitor, is described. The synthesis features the highly stereoselective aldol reaction of methyl ketone 8b and aldehyde 60c and a Suzuki cross-coupling reaction of the highly functionalized advanced intermediates 12 and 39. Vinyl iodide 12 was synthesized by a 14-step sequence starting from the readily available beta-alkoxy aldehyde 14, while the vinylboronic acid component 39 was synthesized by a nine-step sequence from beta-hydroxy-alpha-methyl butyrate 44 via a sequence involving the alpha-methoxypropargylation of chiral aldehyde 49 with the alpha-methoxypropargylstannane reagent 54. Syntheses of fragments 12 and 39 also feature diastereoselective double asymmetric crotylboration reactions to set several of the critical stereocenters. The Suzuki cross-coupling of 12 and 39 provided seco ester 40, which following conversion to the seco acid underwent smooth macrolactonization to give 41. The success of the macrocyclization required that C(7)-OH be unprotected. The Mukaiyama aldol reaction between aldehyde 60c and the TMS enol ether generated from 8b provided aldol 65 with high diastereoselectivity. Finally, all silicon protecting groups were removed by treatment of the penultimate intermediate 65 with TAS-F (tris(dimethylamino)sulfonium difluorotrimethylsilicate), thereby completing the total synthesis of (-)-bafilomycin A(1).
A New Generation of π-Basic Dearomatization Agents

A new generation of dearomatizing π-bases having the general form {TpM(L)(π-acid)} (where Tp = hydridotris(pyrazolyl)borate, M = rhenium, molybdenum, tungsten, L = variable ligand, and π-acid = CO, NO+) has been developed. These fragments show reactivity patterns similar to those of their pentaammineosmium(II) predecessor, binding aromatic molecules across two carbons and subsequently activating these ligands toward electrophilic addition and cycloaddition reactions. In many cases, these second-generation dearomatization agents show a greater degree of π-back-bonding than was observed for the analogous pentaammineosmium(II) complexes. A number of unprecedented reaction pathways have been discovered for these second-generation systems, most notably a broad array of cyclization reactions. In addition, these chiral-at-metal dearomatization agents are readily resolved and have been utilized in reaction sequences to give highly enantioenriched polycyclic molecules from common aromatic precursors.
The K-Theoretic Formulation of D-Brane Aharonov-Bohm Phases

The topological calculation of Aharonov-Bohm phases associated with D-branes in the absence of a Neveu-Schwarz B-field is explored. The K-theoretic classification of Ramond-Ramond fields in Type II and Type I theories is used to produce formulae for the Aharonov-Bohm phase associated with a torsion flux. A topological construction shows that K-theoretic pairings to calculate such phases exist and are well defined. An analytic perspective is then taken, obtaining a means for determining Aharonov-Bohm phases by way of the reduced eta-invariant. This perspective is used to calculate the phase for an experiment involving the (−1) −8 system in Type I theory and compared with previous calculations performed using different methods.
Thermal desorption spectroscopy of palladium and copper on silica

Abstract Thermal desorption spectroscopy of palladium and copper films grown on clean silica substrates was performed using CO2 laser heating. After cleaning the surface by high temperature heating, a controlled, low coverage dose of metal atoms was deposited on the substrate. Temperature ramping was achieved using a constant laser power, the value of which depended on the nature of the metal and substrate as well as the substrate size. At high temperatures (above 1025 K for palladium and above 975 K for copper), metal films vaporize and desorption spectra provide information about the nature of the metal deposit and metal-support interaction. With increasing coverage of palladium on silica, a positive temperature shift in the leading edge of desorption was seen. At higher coverages, above about 2 × 1015 atoms cm-2, a common leading edge appears and zero-order kinetic analysis gave Eact values between 3.9 and 4.3 ± 0.1 eV which can be compared with the value of 3.83 eV for ΔHvap(1200 K) for palladium metal. Similar coverage-dependent properties were not seen for copper on silica; instead, a common desorption leading edge appeared down to submonolayer coverages. Zero-order analysis at about 1 × 1015 atoms cm-2 gave an Eact of 3.3 ± 0.1 eV, which is comparable with the value of 3.44 eV for ΔHvap(1100 K) for copper metal.
Kondo effect in nanostructures

Kondo effect arises whenever a coupling to the Fermi gas induces transitions within the otherwise degenerate ground state multiplet of an interacting system. Both coupling to the Fermi gas and interactions are naturally present in any nanoscale transport experiment. At the same time, many nanostructures can easily be tuned to the vicinity of a degeneracy point. This is why the Kondo effect in its various forms often influences the low temperature transport in meso- and nanoscale systems. In this short review we discuss the basic physics of the Kondo effect and its manifestations in the low-temperature electronic transport through a single electron transistor.
Pharmacokinetics and its role in small molecule drug discovery research.

Pharmacokinetics (PK), which describes the disposition of a drug in the body, should be a primary consideration in the selection of a drug candidate, ultimately contributing to its eventual clinical success or failure. Accordingly, a sound understanding of PK concepts and an appreciation of the judicious use of PK and related (e.g., metabolism, transporter) data in drug discovery can be beneficial to those involved in the process. This review defines important PK parameters (e.g., clearance, volume of distribution, half-life), describes methods of PK data analysis (noncompartmental vs. compartmental) and provides an overview of additional concepts such as allometric scaling, PK/pharmacodynamic modeling, and nonlinear PK. Furthermore, the role and strategic use of PK screens in drug discovery are discussed.
Orbital ordering in orthorhombic perovskites

In addition to a cooperative MO6/2 site rotation, orthorhombic AMO3 perovskites with Pbnm space group have a universal, intrinsic MO6/2 site distortion consisting of an orthorhombic component and a reduction from 90° of the O–M–O bond angle α that subtends the octahedral-site edges parallel to the orthorhombic b axis. RMO3 perovskites (R = rare earth or Y, M = 3d-block transition metal) exhibit a maximum intrinsic orthorhombic site distortion at an R3+-ion radius IR ≈ 1.11 A and a reduction of α that increases with IR > 1.11 A. How the universal site distortions influence Jahn–Teller cooperative orbital orderings on the M cations is illustrated in four orthorhombic perovskite families: RTiO3, RVO3, RMnO3, and RNiO3.
Crystal-field effects in spinel: oxidation states of iron and chromium

Abstract Experiments with a chrome-iron spinel from Lesotho (Free State), a spinel from the Philippines, and two lunar spinels have led to a system for assigning crystal-field transitions to observed absorption bands of chromium and iron. It was possible to detect and assign bands for tetrahedrally coordinated Fe2+, Fe3+ and Cr2+ ions, and for octahedrally coordinated Fe2+ and Cr3+ ions in the spinels. Data on the Lesotho spinel treated at 1400°C and P O 2 = 10 −11.5 atm were used to relate composition, partial pressure of oxygen, temperature, and coordination site in spinel crystals.
Infrared emission spectrum of the atmosphere

A device for the convenient quantitative measurement of the thermal radiation from the atmosphere has been developed. In the instrument the emission spectrum of the earth’s atmosphere as observed at ground level is compared automatically with a spectrum approximating that of a blackbody at the boiling point of liquid nitrogen at atmospheric pressure. The most prominent features of the atmospheric spectrum between 4 μ and 15.5 μ, observed during daylight and darkness when the sky is clear, are due to emission by carbon dioxide, ozone, and water vapor; the intensity of the water vapor emission shows pronounced variations with atmospheric temperature and humidity. The spectrum of an overcast sky resembles that of a blackbody. By comparing the recorder traces of the atmospheric spectra with similar traces obtained with a blackbody source, it is possible to estimate the effective radiation temperature of various portions of the sky for various atmospheric conditions.
Characterizing and reproducing working set size dynamics

Abstract A characterization of program referencing dynamics based on the temporal behavior of memory demand (as represented by the working set size of a program for a given window size) is proposed. A deterministic generative model which produces a references string having a given dynamic characterization is then presented, and its practical implementation is discussed. An experimental study of the accuracy and the viability of such a model is performed, together with a theoretical and empirical investigation of the feasibility of constructing a synthetic program which produces an approximation to that artificial string, thereby exhibiting the given dynamic behavior. The results for working-set-like environments with window sizes larger than or equal to that used in the generation of the artificial string are satisfactory, but those for other types of memory policies reveal that improvements to the string generation algorithm or different characterizations are needed.
Do Big 4 Auditors Provide Higher Audit Quality after Controlling for the Endogenous Choice of Auditor

SUMMARY: Recent research suggests that Big 4 auditors do not provide higher audit quality than other auditors, after controlling for the endogenous choice of auditor. We re-examine this issue using the incidence of accounting restatements as a measure of audit quality. Using a propensity-score matching procedure similar to that used by recent research to control for clients' endogenous choice of auditor, we find that clients of Big 4 audit firms are less likely to subsequently issue an accounting restatement than are clients of other auditors. In additional tests, we find weak evidence that clients of Big 4 auditors are less likely to issue accounting restatements than are clients of Mid-tier auditors (Grant Thornton and BDO Seidman). Taken together, the evidence suggests that Big 4 auditors do perform higher quality audits. JEL Classifications: M41, M42 Data Availability: All data are publicly available from sources identified in the text.
Charged particle depletion surrounding Saturn's F ring - Evidence for a moonlet belt?

An improved model of the Saturn magnetosphere and of the locations of known moons and rings is invoked in the present reconsideration of Pioneer 11 observations of five abrupt depletions in the flux of trapped magnetospheric electrons within a 2000-km-wide band around the F ring. It is inferred that the observed depletions of charged particles are caused by clumps of material with low optical depth; it is further hypothesized that these clumps are composed of regolith ejecta, are generated by collisions occurring within a belt of unseen, moonlet-scale (or smaller) objects occupying the entire radial region between Pandora and Prometheus. Attention is given to a self-consistent scenario in which these debris clouds are created, longitudinally spread, swept up onto belt object surfaces, and then thrown off by a subsequent collision.
Status of solar sail technology within NASA

Abstract In the early 2000s, NASA made substantial progress in the development of solar sail propulsion systems for use in robotic science and exploration of the solar system. Two different 20-m solar sail systems were produced. NASA has successfully completed functional vacuum testing in their Glenn Research Center’s Space Power Facility at Plum Brook Station, Ohio. The sails were designed and developed by Alliant Techsystems Space Systems and L’Garde, respectively. The sail systems consist of a central structure with four deployable booms that support each sail. These sail designs are robust enough for deployment in a one-atmosphere, one-gravity environment and are scalable to much larger solar sails – perhaps as large as 150 m on a side. Computation modeling and analytical simulations were performed in order to assess the scalability of the technology to the larger sizes that are required to implement the first generation of missions using solar sails. Furthermore, life and space environmental effects testing of sail and component materials was also conducted. NASA terminated funding for solar sails and other advanced space propulsion technologies shortly after these ground demonstrations were completed. In order to capitalize on the $30 M investment made in solar sail technology to that point, NASA Marshall Space Flight Center funded the NanoSail-D, a subscale solar sail system designed for possible small spacecraft applications. The NanoSail-D mission flew on board a Falcon-1 rocket, launched August 2, 2008. As a result of the failure of that rocket, the NanoSail-D was never successfully given the opportunity to achieve orbit. The NanoSail-D flight spare was flown in the Fall of 2010. This review paper summarizes NASA’s investment in solar sail technology to date and discusses future opportunities.
Scandium(III) Triflate as an Efficient and Reusable Catalyst for Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones

Abstract Sc(III) triflate efficiently catalyzes the three‐component condensation reaction of an aldehyde, a β‐ketoester, and urea in refluxing acetonitrile to afford the corresponding 3,4‐dihydropyrimidin‐2(1H)‐ones in excellent yields. The catalyst can be recovered and reused, making this method friendly and environmentally acceptable.
Preparation of a protected triamino analogue of cholic acid and sequential incorporation of amino acids in solution and on a solid support.

We have prepared a triamine derivative of cholic acid with protecting groups on the amines that allow sequential amide formation. The triamine was formed from 3α,7α,12α-trihydroxycholan-24-ol with good stereoselectivity. Sequential removal of the amine protecting groups and amide formation was achieved in high-yielding steps and was performed in solution and on a solid support.
Regio- and enantioselective iridium-catalyzed intermolecular allylic etherification of achiral allylic carbonates with phenoxides.

An enantioselective and regioselective iridium-catalyzed allylic etherification is described. The reaction of sodium and lithium aryloxides with achiral (E)-cinnamyl and terminal aliphatic allylic electrophiles in the presence of 2 mol % of an iridium−phosphoramidite complex provides chiral allylic aryl ethers in high yields and excellent levels of regio- and enantioselectivity. Lithium aryloxides containing a single substituent at an ortho, meta, or para position as well as sterically hindered phenoxides were tolerated. Reactions in THF displayed the most suitable balance of rate, regio-, and enantioselectivity. High ee's were also observed for the products from the reaction of alkyl (E)-allylic carbonates.
Control-Relevant Discretization of Nonlinear Systems With Time-Delay Using Taylor-Lie Series

A new time-discretization method for the development of a sampled-data representation of a nonlinear continuous-time input-driven system with time delay is proposed. It is based on the Taylor-Lie series expansion method and zero-order hold assumption. The mathematical structure of the new discretization scheme is explored and characterized as useful for establishing concrete connections between numerical and system-theoretic properties. In particular, the effect of the time-discretization method on key properties of nonlinear control systems, such as equilibrium properties and asymptotic stability, is examined. The resulting time-discretization provides a finite-dimensional representation for nonlinear control systems with time-delay enabling the application of existing controller design techniques. The performance of the proposed discretization procedure is evaluated using the case study of a two-degree-of-freedom mechanical system that exhibits nonlinear behavior. Various sampling rates and time-delay values are considered.
Differential Virulence of Clinical and Bovine-Biased Enterohemorrhagic Escherichia coli O157:H7 Genotypes in Piglet and Dutch Belted Rabbit Models

Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) is an important cause of food and waterborne illness in the developed countries. Cattle are a reservoir host of EHEC O157 and a major source of human exposure through contaminated meat products. Shiga toxins (Stxs) are an important pathogenicity trait of EHEC O157. The insertion sites of the Stx-encoding bacteriophages differentiate EHEC O157 isolates into genogroups commonly isolated from cattle but rarely from sick humans (bovine-biased genotypes [BBG]) and those commonly isolated from both cattle and human patients (clinical genotypes [CG]). Since BBG and CG share the cardinal virulence factors of EHEC O157 and are carried by cattle at similar prevalences, the infrequent occurrence of BBG among human disease isolates suggests that they may be less virulent than CG. We compared the virulence potentials of human and bovine isolates of CG and BBG in newborn conventional pig and weaned Dutch Belted rabbit models. CG-challenged piglets experienced severe disease accompanied by early and high mortality compared to BBG-challenged piglets. Similarly, CG-challenged rabbits were likely to develop lesions in kidney and intestine compared with the BBG-challenged rabbits. The CG strains used in this study carried stx2 and produced significantly higher amounts of Stx, whereas the BBG strains carried the stx2c gene variant only. These results suggest that BBG are less virulent than CG and that this difference in virulence potential is associated with the Stx2 subtype(s) carried and/or the amount of Stx produced.
On De Jong’s conjecture

Let X be a smooth projective curve over a finite field F q . Let ρ be a continuous representation π(X) → GL n (F), where F = F l ((t)) with F l being another finite field of order prime to q. Assume that $$ \rho \left| {_{\pi (\bar X)} } \right. $$ is irreducible. De Jong’s conjecture says that in this case $$ \rho (\pi (\bar X)) $$ is finite. As was shown in the original paper of de Jong, this conjecture follows from an existence of an F-valued automorphic form corresponding to ρ is the sense of Langlands. The latter follows, in turn, from a version of the Geometric Langlands conjecture. In this paper we sketch a proof of the required version of the geometric conjecture, assuming that char(F) ≠ 2, thereby proving de Jong’s conjecture in this case.
Laser controlled molecular switches and transistors

We investigate the possibility of optical current control through single molecules which are weakly coupled to leads. A master equation approach for the transport through a molecule is combined with a Floquet theory for the time-dependent molecule. This yields an efficient numerical approach to the evaluation of the current through time-dependent nano-structures in the presence of a finite external voltage. We propose tunable optical current switching in two- and three-terminal molecular electronic devices driven by properly adjusted laser fields, i.e., a novel class of molecular transistors.
Two-part reconstruction in compressed sensing

Two-part reconstruction is a framework for signal recovery in compressed sensing (CS), in which the advantages of two different algorithms are combined. Our framework allows to accelerate the reconstruction procedure without compromising the reconstruction quality. To illustrate the efficacy of our two-part approach, we extend the author's previous Sudocodes algorithm and make it robust to measurement noise. In a 1-bit CS setting, promising numerical results indicate that our algorithm offers both a reduction in run-time and improvement in reconstruction quality.
Refining edges detected by a LoG operator

Abstract The Laplacian-of-Gaussian (LoG) operator is one of the most popular operators used in edge detection. This operator, however, has some problems: zero-crossings do not always correspond to edges, and edges with an asymmetric profile introduce a symmetric bias between edge and zero-crossing locations. In this paper, we offer solutions to these two problems. First, for one-dimensional signals, such as slices from images, we propose a simple test to detect “true” edges, and, for the problem of bias, we propose different techniques: the first one combines the results of the convultion of two LoG operators of different standard deviations, whereas the others sample the convolution with a single LoG filter at two points besides the zero-crossing. In addition to localization, these methods allow us to further characterize the shape of the edge. We then present an implementation of these techniques for edges in 2D images, in which we apply the refining process to linear segments approximating the detected contours. The methods are illustrated on several examples.
Tetrahedral curves via graphs and Alexander duality

Abstract A tetrahedral curve is a (usually nonreduced) curve in P 3 defined by an unmixed, height two ideal generated by monomials. We characterize when these curves are arithmetically Cohen–Macaulay by associating a graph with each curve and, using results from combinatorial commutative algebra and Alexander duality, relating the structure of the complementary graph to the Cohen–Macaulay property.
Current/Voltage-Based Detection of Faults in Gears Coupled to Electric Motors

Gears form a critical part of many electromechanical systems. Since gear faults cause vibrations, and vibration-based diagnostics are very reliable, this has traditionally been the most commonly used approach to detecting gear faults. However, it is expensive due to the use of high-priced accelerometers and sensor wiring. This paper proposes an alternative way of detecting faults in gears coupled to brushless dc motors by monitoring either the motor current or voltage. It will be shown that gear faults create unique spectral components in the voltage and current spectrums. The faults investigated include damage to gear teeth and loss of lubrication. Experimental and simulation results demonstrate that motor current/voltage signature analysis is a viable tool to detect these gear faults and is a cheaper alternative than vibration-based fault-detection scheme