cssi/SciSciGPT-SciSciNet huggingface dataset:
Enantioselective synthesis of 1-vinyltetrahydroisoquinolines via Pd-catalyzed intramolecular asymmetric allylic amination reactions

1-Vinyltetrahydroisoquinolines serve as versatile intermediates for the synthesis of a variety of naturally occurring isoquinoline alkaloids. 1-Vinyl-6,8-dimethoxytetrahydroisoquinoline 4 and 1-vinyl-5,6,7-trimethoxytetrahydroisoquinoline 6 with >90% ee by means of Pd-catalyzed intramolecular asymmetric allylic amination reactions, using MPN and BOP ligands, developed in our laboratory. The fine-tuning capability of the MPN and BOP ligands has played a significant role in the optimization of enantioselectivity. Interesting substituent effect as well as solvent effect on the product selectivity and enantioselectivity was observed. Plausible mechanisms are proposed, which can accommodate various findings, including the critical importance of the activation of the trifluoroamide moiety through its coordination to the Lewis acidic Pd2+ metal center.
Linearized Integral Theory of Three-Dimensional Unsteady Flow in a Shear Layer

A linearized integral theory is developed for calculating the pressure on a perturbed wall in three-dimensi onal unsteady supersonic flow in the presence of a shear layer. An explicit formula for the wall pressure is given for an array of panels undergoing simple harmonic motion. Asymptotic and numerical results are presented for the kernel of the wall pressure. The integral theory reduces to the exact linearized inviscid theory in the limit of zero shear layer thickness. Also, it reduces to the two-dimensional steady-state theory of Ref. 1. For a finite layer, there are three integral thickness parameters. A critical Mach number is calculated (^1.8) below which there is upstream influence and the kernel is attenuated by the shear layer. For supercritical Mach numbers, there is no upstream influence.
On the locality of codeword symbols in non-linear codes

Coordinate i of an error-correcting code has locality r if its value is determined by some r other coordinates. Recently an optimal trade-off between information locality of linear codes, code distance, and redundancy has been obtained. Furthermore, for linear codes meeting this trade-off, structure theorems were derived. In this work we generalize the trade-off and structure theorems to non-linear codes.
Cosmology solved? Maybe

Abstract For two decades the hot big-bang model as been referred to as the standard cosmology - and for good reason. For just as long cosmologists have known that there are fundamental questions that are not answered by the standard cosmology and point to a grander theory. The best candidate for that grander theory is inflation + cold dark matter. It holds that the Universe is flat, that slowly moving elementary particles left over from the earliest moments provide the cosmic infrastructure, and that the primeval density inhomogeneities that seed all the structure arose from quantum fluctuations. There is now prima facie evidence that supports two basic tenets of this paradigm. An avalanche of high-quality cosmological observations will soon make this case stronger or will break it. Key questions remain to be answered; foremost among them are: identification and detection of the cold dark matter particles and elucidation of the dark-energy component. These are exciting times in cosmology!
Law and the Public's Health:

This installment of Law and the Public’s Health examines the problem of state laws that permit various types of insurers to exclude from coverage all costs related to “intoxication” injuries and considers the implications of these laws for public health policy and practice. Although laws permitting insurers to use intoxication exclusionary clauses have fallen out of favor with the National Association of Insurance Commissioners (NAIC), nearly all states and the District of Columbia continue to explicitly or implicitly permit licensed insurers to exclude coverage for diagnostic and treatment services for conditions related to the use of alcohol or drugs. 1 Such exclusions not only have potentially significant consequences for health care quality and financing, but also may impede efforts to protect the public’s health through efforts to encourage providers to promptly identify and begin treatment for acute intoxication and chronic substance use disorders. Indeed, laws permitting intoxication exclusions represent a fundamental disjunction between evidence-based medical care on the one hand and health financing on the other, since intoxication exclusions financially disincentivize precisely the type of medical response that has been identified as a benchmark of clinically appropriate medical care. 2
Analysis of some projection method based preconditioners for models of incompressible flow

In this paper, several projection method based preconditioners for various incompressible flow models are studied. In the derivations of these projection method based preconditioners, we use three different types of the approximations of the inverse of the Schur complement, i.e., the exact inverse, the Cahouet-Chabard type approximation and the BFBt type approximation. We illuminate the connections and the distinctions between these projection method based preconditioners and those related preconditioners. For the preconditioners using the Cahouet-Chabard type approximation, we show that the eigenvalues of the preconditioned systems have uniform bounds independent of the parameters and most of them are equal to 1. The analysis is based on a detailed discussion of the commutator difference operator. Moreover, these results demonstrate the stability of the staggered grid discretization and reveal the effects of the boundary treatment. To further illustrate the effectiveness of these projection method based preconditioners, numerical experiments are given to compare their performances with those of the related preconditioners. Generalizations of the projection method based preconditioners to other saddle point problems are also discussed.
Bulls, bears and market sheep

Abstract A deterministic excess demand model of stock market behavior is presented that generates stochastically fluctuating prices and randomly switching bear and bull markets.
On the inevitability of divided government and improbability of a complete separation of powers

This paper provides a tightly written overview and modest extension of the constitutional exchange and evolution model developed in Perfecting Parliament and uses that approach to analyze the division of authority that one would expect to see in contemporary constitutional governments. The analysis suggests that constitutions tend to be written, based on the king and council template, and buttressed by a more or less independent court system. Moreover, it suggests that constitutions change at the margin through time as constitutional bargaining takes place. This suggests that a complete separation of power is unlikely to be observed in the long run. Empirical evidence developed from the IAEP data base is consistent with these predictions.
THREAD (three-dimensional reconstruction and display) with biomedical applications in neuron ultrastructure and computerized tomography

THREAD is a computer system capable of displaying three-dimensional images from serial two-dimensional sections. The serial two-dimensional input images can either be in the format of 35 mm films or in digital cross sectional pictures of live patients generated by the ACTA (Automatic Computerized Transverse Axial) Scanner. The hardware components of the system consists of FIDAC (Film Input to Digital Automatic Computer), MACDAC (MAn Communication and Display to Automatic Computer), and the Display Subsystem of the ACTA-Scanner. The software includes such features as segmentation, rotation, hidden line removal, shading plane definition, shading and display. Two examples, one from serial electron micrographs of a neuron and the other from serial ACTA, live patient, scans are given to demonstrate the capability of the system.
The effects of phosphine ligands on the benzannulation reaction of molybdenum carbene complexes with alkynes

The effects of phosphine substitution at the metal on the reactions of group 6 pentacarbonyl Fischer carbene complexes with alkynes have been found not to be those expected from what is known about these reactions. The product distribution for the reaction of the molybdenum complex 5 with 3-hexyne changes dramatically from predominately indene product to predominately quinone product upon substitution of one of the CO ligands in 5a with a tri-n-butylphosphine.
ASYMMETRIC SYNTHESIS OF ALKYLARYLCARBINOLS VIA REACTION OF A CHIRAL PINANEDIOL ALKYLBORONIC ESTER WITH ARYLMETHYL CHLORIDES

Abstract The reaction of arylmethyl chlorides with chiral pinanediol esters of alkylboronic acids in the presence of lithium dicyclohexylamide affords chiral alkylarylcarbinols in good stereochemical yields after oxidation.
Techniques for selecting pose algorithms

Abstract A technique for selecting one pose algorithm from m algorithms containing zero mean Gaussian errors is derived. The procedure consists of a two stage analysis. First, the joint entropy of each algorithm is found. The algorithm with minimum entropy is shown to possess the greatest possible lower bound reliability of meeting any quadratic specification of the pose error. Hence it is the best pose algorithm to select without further analysis. In addition, the entropy of pose measurements is shown to be invariant with respect to homogeneous coordinate transformations, so the analysis is simplified for physically distributed robotic systems. To guarantee a minimum reliability, a second stage of analysis is necessary. Methods of calculating reliability bounds for a given quadratic specification are derived. The resulting bounds require three orders of magnitude less computations than the alternative, Monte Carlo simulations. Entropy analysis requires another order of magnitude less computations than reliability analysis, so the computations are reduced by a total of four orders of magnitude. The concepts are simulated using a visual pose measurement system developed by NASA, where each viewpoint of the camera is considered to be a separate pose algorithm (accuracy depends upon viewpoint). The results indicate that entropy is very effective for selecting pose algorithms, and the reliability greatest lower bound is close to the actual reliability.
Synthesis of Variable-Aspect-Ratio, Single-Crystalline ZnO Nanostructures

Variable-aspect-ratio (length/diameter), one-dimensional (1-D) ZnO nanostructures (nanorods and nanowires) were prepared in alcohol/water solution by reacting a Zn2+ precursor with an organic weak base, tetramethylammonium hydroxide (Me4NOH). The effect of the experimental parameters (temperature, base concentration, reaction time, and water content) on nucleation, growth, and the final morphology of the ZnO nanostructures was investigated. The low-temperature syntheses (75-150 degrees C) yielded aspect ratios of the 1-D ZnO nanostructures that depended on the water content. The individual ZnO nanorods and nanowires were determined to be perfect, single crystals with their c axes as the primary growth direction.
Aspects of ABJM orbifolds with discrete torsion

We analyze orbifolds with discrete torsion of the ABJM theory by a finite subgroup Γ of SU(2) × SU(2) . Discrete torsion is implemented by twisting the crossed product algebra resulting after orbifolding. It is shown that, in general, the order m of the cocycle we chose to twist the algebra by, enters in a non-trivial way in the moduli space of vacua of the resulting theory. To be more precise, the circle identified with the M-theory fiber is multiplied by a factor of m. Then, the action of the discrete quotient on the fiber is shown to be given by \( {\mathbb{Z}_{\frac{{k\left| \Gamma \right|}}{m}}} \). This is shown to be in agreement with previously found results in the literature regarding orbifolds of the ABJM theory. We present a general analysis on how this quotient arises along with a detailed analysis of the cases where Γ is abelian.
Integrable boundary conditions and reflection matrices for the O(N) nonlinear sigma model

Abstract We find new integrable boundary conditions, depending on a free parameter g, for the O ( N ) nonlinear σ model, which are of nondiagonal type, that is, particles can change their “flavor” through scattering off the boundary. These boundary conditions are derived from a microscopic boundary Lagrangian, which is used to establish their integrability, and exhibit integrable flows between diagonal boundary conditions investigated previously. We solve the boundary Yang–Baxter equation, connect these solutions to the boundary conditions, and examine the corresponding integrable flows.
Cuts and flows of cell complexes

We study the vector spaces and integer lattices of cuts and flows associated with an arbitrary finite CW complex, and their relationships to group invariants including the critical group of a complex. Our results extend to higher dimension the theory of cuts and flows in graphs, most notably the work of Bacher, de la Harpe, and Nagnibeda. We construct explicit bases for the cut and flow spaces, interpret their coefficients topologically, and give sufficient conditions for them to be integral bases of the cut and flow lattices. Second, we determine the precise relationships between the discriminant groups of the cut and flow lattices and the higher critical and cocritical groups with error terms corresponding to torsion (co)homology. As an application, we generalize a result of Kotani and Sunada to give bounds for the complexity, girth, and connectivity of a complex in terms of Hermite's constant.
Private money as a competing medium of exchange

Abstract By introducing costly centralized exchange into a traditional search theoretic decentralized market, where money can mediate trade, we show private money can arise endogenously because it is profitable for the centralized intermediary to satisfy the demand for money that will naturally arise. Trading money to another agent for a good, rather than trading good for good through the centralized intermediary, allows the money holder to obtain the good while avoiding the fee the centralized intermediary must charge to cover its costs. The model provides a set of pure strategy monetary equilibria where the quantity of privately issued money is a monotonically increasing function of the confidence agents have in money. The model indicates that the circulation of fiat money is explained by the role it can play in reducing transaction costs more so than the role it can play as a medium of exchange in resolving the double coincidence of wants problem.
Effects of sample orientation on the corrosion of zinc in ammonium sulfate and sodium hydroxide solutions

Abstract The corrosion and electrochemical properties of three zinc single crystal surfaces with different orientations have been investigated. In near-neutral 1 M (NH4)2SO4, the corrosion rates on all three surfaces were found to be similar. However, the SEM morphologies of the corresponding corroded surfaces were markedly different from each other, but consistent with preferential attack of {11 2 0} surfaces. In alkaline 0.5 N NaOH solution, the three sample orientations showed significantly different reactivities, with the (11 2 0) surface exhibiting the highest reactivity and corrosion rate. Here, passivation ultimately occurred and the difference in the corrosion performance of the three surfaces, even for small overvoltages, is attributed to the presence of oxide or hydrated oxide films.
Off-centers: A new type of Steiner points for computing size-optimal quality-guaranteed Delaunay triangulations

We introduce a new type of Steiner points, called off-centers, as an alternative to circumcenters, to improve the quality of Delaunay triangulations in two dimensions. We propose a new Delaunay refinement algorithm based on iterative insertion of off-centers. We show that this new algorithm has the same quality and size optimality guarantees of the best known refinement algorithms. In practice, however, the new algorithm inserts fewer Steiner points, runs faster, and generates smaller triangulations than the best previous algorithms. Performance improvements are significant especially when user-specified minimum angle is large, e.g., when the smallest angle in the output triangulation is 30^o, the number of Steiner points is reduced by about 40%, while the mesh size is down by about 30%. As a result of its shown benefits, the algorithm described here has already replaced the well-known circumcenter insertion algorithm of Ruppert and has been the default quality triangulation method in the popular meshing software Triangle.
Localization and scaling in the quantum Hall regime.

A new experimental study of the quantum Hall effect is presented. Detailed measurements are made of the temperature and magnetic field dependences in the electronic transport coefficients, ${\ensuremath{\sigma}}_{\mathrm{xx}}$ and ${\ensuremath{\sigma}}_{\mathrm{xy}}$, in ${\mathrm{In}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$As-InP heterostructures for the n=0 and 1 Landau levels. The results are studied in the context of the (two-parameter) renormalization-group theory of the integral quantum Hall effect.
Unknotting information from Heegaard Floer homology

We use Heegaard Floer homology to obtain bounds on unknotting numbers. This is a generalisation of Ozsvath and Szabo's obstruction to unknotting number one. We determine the unknotting numbers of 910, 913, 935, 938, 1053, 10101 and 10120; this completes the table of unknotting numbers for prime knots with crossing number nine or less. Our obstruction uses a refined version of Montesinos' theorem which gives a Dehn surgery description of the branched double cover of a knot.
The national biological information infrastructure: present and future

~ding the vast amounts of biorlogical data related to the management, study, and use of biological resources cached in hundreds of databases around the world is difficult at best. According to the President's Council of Advisors on Science and Technology (PCAST), most of this information sits unused because of a lack of eftlcient means to retrieve and derive comprehensible information from it. A solution is in the midst of development: The National Biological Information Infrastructure, an initiative of the US Geological Survey's Biological Resources Division (BRD), will eventually allow researchers, land and natural resource managers, students, and the general public to locate these databases, query multiple databases simultaneously, and retrieve data. But NBIl is still far from achieving this goal, and the substantial funding needed to make biological data more accessible via NBIl comes from the same dwindling pool of money for research that generates those data. When NBIl is completed, users will be able to draw from any number of databases to assess biological and environmental processes and conditions. NBIl will also provide software to help users analyze these data. For example, a property owner or manager trying to maintain good habitat for wildlife could use NBIl to track long-term trends in vegetation cover and changes in animal and plant species diversity, composition, and abundance on the property. The property owner could also search for literature to determine possible causes of observed changes and to identify restoration measures. Initiated in 1994, NBIl is still in what its creators refer to as the "first generation." Described by NBIl manager Anne Frondorf as a "distributed electronic federation;' NBIl, in its cur-
The Bismuth (III) Chloride Mediated N-Derivatization of L-Proline and Pipecolinic Esters in Aqueous Media

Abstract An efficient method for the N-derivatization, in aqueous media, of L-proline and pipecolinic esters is reported, using benzotriazole as a synthetic auxiliary.
Dense stereo correspondence using color

We investigate the use of chromatic information in dense stereo correspondence. Specifically the chromatic photometric constraint which is used to specify a mathematical optimality criterion for solving the dense stereo correspondence problem is developed. The result is a theoretical construction for developing dense stereo correspondence algorithms which use chromatic information. The efficacy of using chromatic information via this construction is tested by implementing singleand multi-resolution versions of a stereo correspondence algorithm which uses simulated annealing as a means of solving the optimization problem. Results demonstrate that the use of chromatic information can significantly improve the performance of dense stereo correspondence. 1.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Extended Emission-Line Regions: Remnants of Quasar Superwinds?

We give an overview of our recent integral-field-unit spectroscopy of luminous extended emission-line regions (EELRs) around low-redshift quasars, including new observations of five fields. Previous work has shown that the most luminous EELRs are found almost exclusively around steep-spectrum radio-loud quasars, with apparently disordered global velocity fields, and little, if any, morphological correlation with either the host galaxy or the radio structure. Our new observations confirm and expand these results. The EELRs often show some clouds with velocities exceeding 500 km s^(–1), ranging up to 1100 km s^(–1), but the velocity dispersions, with few exceptions, are in the 30-100 km s^(–1) range. Emission-line ratios show that the EELRs are clearly photoionized by the quasars. Masses of the EELRs range up to 10^(10) M☉. Essentially all of the EELRs show relatively low metallicities, and they are associated with quasars that, in contrast to most, show similarly low metallicities in their broad-line regions. The two objects in our sample that do not have classical double-lobed radio morphologies (3C 48, with a compact-steep-spectrum source; Mrk 1014, radio quiet, but with a weak compact-steep-spectrum source) are the only ones that appear to have recent star formation. While some of the less luminous EELRs may have other origins, the most likely explanation for those in our sample is that they are examples of gas swept out of the host galaxy by a large-solid-angle blast wave accompanying the production of the radio jets. The triggering of the quasar activity is almost certainly the result of the merger of a gas-rich galaxy with a massive, gas-poor galaxy hosting the supermassive black hole.
Recent developments in sheet molding compound technology

The molding of fiber-reinforced thermoset components is a complex process involving a highly exothermic chemical reaction which takes place in the presence of flow and thermal gradients. The flow in turn is complicated by time and temperature-dependent rheological characteristics. The industry has grown largely on the basis of empirical developments. However, numerous problems do remain which required increased understanding for solution. This report reviews work underway in numerous laboratories to characterize the flow and cure of SMC and phenomena associated with these processes such as orientation, mechanical properties, residual internal stresses, mold fill, and surface defects.
Tax Distortions and Global Climate Policy

Abstract We consider the efficiency implications of policies to reduce global carbon emissions in a world with pre-existing tax distortions. We first note that the weak double dividend, the proposition that the welfare improvement from a tax reform where environmental taxes are used to lower distorting taxes must be greater than the welfare improvement from a reform where the environmental taxes are returned in a lump sum fashion, need not hold in a world with multiple distortions. We then present a large-scale computable general equilibrium model of the world economy with distortionary taxation. We use this model to evaluate a number of policies to reduce carbon emissions. We find that the weak double dividend is not obtained in a number of European countries. Results also demonstrate the point that the interplay between carbon policies and pre-existing taxes can differ markedly across countries. Thus, one must be cautious in extrapolating the results from a country specific analysis to other countries.
Finite Type Link Homotopy Invariants

In [2], Bar-Natan used unitrivalent diagrams to show that finite type invariants classify string links up to homotopy. In this paper, I will construct the correct spaces of chord diagrams and unitrivalent diagrams for links up to homotopy. I will use these spaces to show that, far from classifying links up to homotopy, the only rational finite type invariants of link homotopy are the linking numbers of the components.
Large-area atmospheric Cherenkov detectors for high-energy gamma-ray astronomy.

This paper describes the development of new ground-based gammaray detectors to explore the energy region between 20 and 200 GeV. This region in energy is interesting because it is currently unexplored by any experiment. The proposed detectors use the atmospheric Cherenkov technique, in which Cherenkov radiation produced in the gamma-ray air showers is detected using mirrors and light-sensitive devices. The important feature of the proposed experiments is the use of large mirror collection areas, which should allow for a significant improvement (i.e. reduction) in energy threshold over existing experiments. Large mirror areas are available for relatively low cost at central tower solar power plants, and there are two groups developing gamma-ray experiments using solar heliostat arrays. This paper summarizes the progress in the design of experiments using this novel approach.
Land use regulations and the returns to low-income homeownership

I investigate the relationship between land use regulations and the house prices of urban low-income homeowners in the United States between 1998 and 2010. Because low-income homeowners generally hold a larger fraction of their wealth as home equity and are less likely to sustain homeownership, the overall financial position of this population is especially dependent on house price movements during short holding periods and the timing of house purchase and sale. The data used for analysis include zip-code-level house price estimates provided by Fannie Mae and proprietary mortgage origination data for a representative sample of low-income US homeowners who received community reinvestment mortgages between 1998 and 2004. I estimate a series of linear mixed-effects models to predict house price appreciation and the risk premium associated with investment in housing as opposed to a risk-free asset. Controlling for a variety of related factors, including land scarcity and subprime lending activity, I find that land use regulations are associated with greater house price volatility and a greater risk premium for urban low-income households. Thus, the results suggest that the dependence of low-income homeowner wealth on the timing of house purchase and sale is weaker in less regulated markets.
Liquidity Provision, Interest Rates, and Unemployment

Abstract The effective liquidity supply of the economy—the weighted-sum of all assets that serve as media of exchange—matters for interest rates and unemployment. We formalize this idea by adding an over-the-counter market with collateralized trades to the Mortensen–Pissarides model. An increase in public liquidity through a higher supply of real government bonds raises the real interest rate, crowding out private liquidity and increasing unemployment. If unemployment is inefficiently high, keeping liquidity scarce can be socially optimal. A liquidity crisis affecting the acceptability of private assets as collateral widens the rate-of-return difference between private and public liquidity, also increasing unemployment.
Absence of crystalline order in two dimensions

It is proven that in two dimensions a system of electrons embedded in a uniform neutralizing positive background and interacting by a potential given by $\frac{{e}^{2}}{r}$ cannot exhibit long-range crystalline order at any finite temperature. The proof is conditional to the following prescription for taking the thermodynamic limit: The potential $\frac{{e}^{2}}{r}$ is replaced by a screened potential $\frac{{e}^{2}{e}^{\ensuremath{-}\ensuremath{\mu}r}}{r}$ and $\ensuremath{\mu}$ is set to zero after the thermodynamic limit is taken.
A De Sitter hoedown

Rotating black holes in de Sitter space are known to have interesting limits where the temperatures of the black hole and cosmological horizon are equal. We give a complete description of the thermal phase structure of all allowed rotating black hole configurations. Only one configuration, the rotating Nariai limit, has the black hole and cosmological horizons both in thermal and rotational equilibrium, in that both the temperatures and angular velocities of the two horizons coincide. The thermal evolution of the spacetime is shown to lead to the pure de Sitter spacetime, which is the most entropic configuration. We then provide a comprehensive study of the wave equation for a massless scalar in the rotating Nariai geometry. The absorption cross section at the black hole horizon is computed and a condition is found for when the scattering becomes superradiant. The boundary-to-boundary correlators at finite temperature are computed at future infinity. The quasinormal modes are obtained in explicit form. Finally, we obtain an expression for the expectation value of the number of particles produced at future infinity starting from a vacuum state with no incoming particles at past infinity. Some of our results are used to provide further evidence for a recent holographic proposal between the rotating Nariai geometry and a two-dimensional conformal field theory.
A new efficient synthesis of 3-(4-pyridinyl)methylindoles

Abstract A new efficient method for the preparation of 3-(4-pyridinyl)methylindoles has been developed. The new method involves coupling of indoles with 4-pyridinecarboxaldehyde to give 3-indolyl 4-pyridinyl methanols, which upon treatment with triethylsilane in the presence of trifluoroacetic acid afford 3-(4-pyridinyl)methylindoles in 64–76% overall yield.
Impact on hearing of routine ear suctioning at the tympanic membrane.

Abstract Objective Patient and equipment safety has become increasingly scrutinized in today's medical care. Routine otolaryngologic evaluation often involves suctioning with Frazier-type suction devices in the ear canal for improved visualization, but data are limited on the potential acoustic trauma from ear canal suction devices. This study intends to document the objective and subjective effects of ear canal suctioning to identify any risk for hearing threshold shifts or other potential negative effects. Patients and Methods Prospective study on 21 healthy volunteers enlisted for evaluation. Presuctioning tympanogram, audiogram, and otoacoustic emissions data were obtained. Spectrum analyses were recorded during ear canal suctioning with a probe microphone placed lateral to the tympanic membrane. Subjective data were recorded, and a follow-up audiogram and otoacoustic emissions were obtained to identify any temporary threshold shifts. Results Spectrum analyses revealed a high degree of variability between subjects. A peak intensity of 111 dB sound pressure level was recorded. All patients tolerated suctioning, and none reported hearing loss. No threshold shifts were observed. Subjective data failed to correlate with the objective recorded intensities. Conclusions Clinicians and patients need to be acutely aware of potential risks and benefits from any medical intervention. Routine ear canal suctioning can be extremely loud and uncomfortable for patients. This study failed to document objective proof of hearing detriment from ear canal suctioning, although the possibility exists during office and surgical intervention. Further study and potential alternative suctioning methods deserve attention.
A graphical programming system with speech input

Abstract An interactive programming system is described where human speech commands and computer graphic input-output facilities are used for the exchange of information between man and machine. The experimental problem solving environment is one of formulating, specifying, debugging and executing (algebraic) procedures interactively on a small processor. The speech recognition system is a real time, syntax directed, limited vocabulary, highly cost effective scheme specifically tailored to this environment. The data transformation operations of the language are verbally specified and the control flow is specified graphically as a two-dimensional directed graph. The semantics of the latter structure is independent of the time sequence of its input. An input restricted (conditional input) pseudo-finite state machine model is used for the continuous syntax checking of the input on an atomic token basis and for directing the speech recognizer. The system has been successfully implemented on a small processor at the University of California, Berkeley.
PSR J1518+4904: A mildly relativistic binary pulsar system

PSR J1518+4904 is a recently discovered 40.9 ms pulsar in an 8.6 day, moderately eccentric orbit. We have measured pulse arrival times for this pulsar over 1.4 yr at several radio frequencies, from which we have derived high-precision rotational, astrometric, and orbital parameters. The upper limit for the period derivative of the pulsar, < 4 × 10-20, gives a characteristic age of at least 1.6 × 1010 yr, which is among the highest known. We find the orbit to be precessing at a rate of 00111 ± 00002 yr-1, which yields a total system mass (pulsar plus companion) of 2.62 ± 0.07 M☉ according to general relativity. Further analysis of the orbital parameters yields a firm upper limit of 1.75 M☉ on the pulsar mass and constrains the companion mass to the range 0.9-2.7 M☉. These masses, together with the sizable orbital eccentricity and other evidence, strongly suggest that the companion is a second neutron star.
Terminal Alkyne-Ethylene Cross-Metathesis: Reaction of 1-Substituted Propargyl Esters at Elevated Ethylene Pressure

Substituted propargylic esters, resistant to complete ethylene cross-metathesis at ambient pressure, underwent cross-metathesis with ethylene at elevated pressure (4 atm) to give 2-substituted butadienes in good to excellent yields. Enantioenriched propargylic acetates, obtained through enzymatic kinetic resolution of secondary propargyl alcohols, similarly underwent ethylene metathesis with retention of stereochemistry at the chiral center.
Neuron PRM: a framework for constructing cortical networks☆

The brain has extraordinary computational power to represent and interpret complex natural environments is essentially determined by the topology and geometry of the brain’s architectures. We present a framework to construct cortical networks which borrows from probabilistic roadmap methods developed for robotic motion planning. We abstract the network as a large-scale directed graph, and use L-systems and statistical data to ‘grow’ neurons that are morphologically indistinguishable from real neurons. We detect connections (synapses) between neurons using geometric proximity tests.
A Cryogenic Infrared Calibration Target

A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R ⩽ 0.003, from 800 to 4800 cm−1 (12 − 2 μm). Upon expanding the spectral range under consideration to 400–10 000 cm−1 (25 − 1 μm) the observed performance gracefully degrades to R ⩽ 0.02 at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to ∼4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials—Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder—are characterized and presented.
Unitary supermultiplets of OSp(1/32,R) and M theory

Abstract We review the oscillator construction of the unitary representations of non-compact groups and supergroups and study the unitary supermultiplets of OSp( 1 32 , R ) in relation to M-theory. OSp( 1 32 , R ) has a singleton supermultiplet consisting of a scalar and a spinor field. Parity invariance leads us to consider OSp( 1 32 , R ) L × OSp( 1 32 , R ) R as the “minimal” generalized AdS supersymmetry algebra of M-theory corresponding to the embedding of two spinor representations of SO(10, 2) in the fundamental representation of Sp(32, R ) . The contraction to the Poincare superalgebra with central charges proceeds via a diagonal subsupergroup OSp( 1 32 , R ) L−R which contains the common subgroup SO(10, 1) of the two SO(10, 2) factors. The parity invariant singleton supermultiplet of OSp( 1 32 , R ) L × OSp( 1 32 , R ) R decomposes into an infinite set of “doubleton” supermultiplets of the diagonal OSp( 1 32 , R ) L−R . There is a unique “CPT self-conjugate” doubleton supermultiplet whose tensor product with itself yields the “massless” generalized AdS11 supermultiplets. The massless graviton supermultiplet contains fields corresponding to those of eleven-dimensional supergravity plus additional ones. Assuming that an AdS phase of M-theory exists we argue that the doubleton field theory must be the holographic superconformal field theory in ten dimensions that is dual to M-theory in the same sense as the duality between the N = 4 super-Yang-Mills in d = 4 and the IIB superstring over AdS5 × S5.
Effects of high-temperature environments on flaw generation and fracture behavior of SiC/SiC composites

Abstract Flaw generation and fracture behavior in Nicalon fiber-reinforced SiC matrix composites are influenced by high temperatures. We evaluated the effects by measuring strength at several temperatures ranging from 800 to 1300 °C, and by microstructural characterization. While composite strength increased from ≈ 400 MPa at room temperature to ≈ 532 MPa at 800 °C, it decreased to ≈ 270 MPa at 1300 °C. Such degradation of composite strength at high temperature is believed to be related to fiber degradation. In-situ fiber strength in composites tested at room and elevated temperatures was estimated by fractographic techniques. The in-situ strength of fibers in composites was significantly lower than that of as-received fibers. This decrease is believed to be related to flaws that develop during processing and to exposure to elevated-temperature service environments.
Reaction rate constant of SO3 + CH3OH in the gas phase

The reaction rates of SO 3 with CH 3 OH in He were measured at total pressures of 0.7-1.6 torr in flow tubes. The concentration of SO 3 was monitored by the SO 2 * fluorescence from excitation of SO 3 at 147 nm. The reaction rate constant of SO 3 +CH 3 OH in the gas phase is determined to be (1.17±0.16)×10 −13 cm 3 molec −1 s −1 at romm temperature
Tachyons in a slice of AdS

Abstract Stability of AdS space allows scalar fields to have negative mass squared as long as the Breitenlohner–Freedman bound is satisfied. In a compactification of AdS instead, to avoid instabilities, a tachyonic bulk mass must be supplemented by appropriate brane actions. In this Letter we clarify the meaning of the lower bound in the Randall–Sundrum scenario with two branes and explain how the instability disappears in the infinite space limit. A CFT interpretation is also given as radiative symmetry breaking.
Enantioselective Total Synthesis of (+)-Largazole, a Potent Inhibitor of Histone Deacetylase†

An enantioselective total synthesis of the cytotoxic natural product (+)-largazole (1) is described. It is a potent histone deacetylase inhibitor. Our synthesis is convergent and involves the assembly of thiazole 3-derived carboxylic acid with amino ester 4 followed by cycloamidation of the corresponding amino acid. The synthesis features an efficient cross-metathesis, an enzymatic kinetic resolution of a β-hydroxy ester, a selective removal of a Boc-protecting group, a HATU/HOAt-promoted cycloamidation reaction, and synthetic manipulations to a sensitive thioester functional group.
Higgs as a slepton

Abstract In theories with TeV scale quantum gravity there is a logical possibility where the electroweak Higgs can be a fourth generation slepton. Despite maximal supersymmetry breaking such a scenario turns out to be tightly constrained, and might be testable already at present collider experiments. Also, a light Higgs is no longer a prediction of supersymmetry.
Minimal surfaces in quasi-Fuchsian 3-manifolds

In this paper, we prove that if a quasi-Fuchsian 3-manifold M contains a closed geodesic with complex length \({\fancyscript {L} = l + i\theta}\) such that \({|\theta|/l \gg 1}\) , where l > 0 and −π ≤ θ < π, then it contains at least two incompressible minimal surfaces near the geodesic.
On the Computational Modeling of Unfluidized and Fluidized Bed Dynamics

Two factors of great importance when considering gas–solid fluidized bed dynamics are pressure drop and void fraction, which is the volume fraction of the gas phase. It is, of course, possible to obtain pressure drop and void fraction data through experiments, but this tends to be costly and time consuming. It is much preferable to be able to efficiently computationally model fluidized bed dynamics. In the present work, ANSYS Fluent® is used to simulate fluidized bed dynamics using an Eulerian–Eulerian multiphase flow model. By comparing the simulations using Fluent to experimental data as well as to data from other fluidized bed codes such as Multiphase Flow with Interphase eXchanges (MFIX), it is possible to show the strengths and limitations with respect to multiphase flow modeling. The simulations described herein will present modeling beds in the unfluidized regime, where the inlet gas velocity is less than the minimum fluidization velocity, and will deem to shed some light on the discrepancies between experimental data and simulations. In addition, this paper will also include comparisons between experiments and simulations in the fluidized regime using void fraction.
Hypersonic Flow Control Using Upstream Focused Energy Deposition

A numerical study of centerline and off-centerline power deposition at a point upstream of a two-dimensional blunt body at Mach 6.5 at 30 km altitude are presented. The full Navier-Stokes equations are used. Wave drag, lift, and pitching moment are presented as a function of amount of power absorbed in the flow and absorption point location. It is shown that wave drag is considerably reduced. Modifications to the pressure distribution in the flow field due to the injected energy create lift and a pitching moment when the injection is off-centerline. This flow control concept may lead to effective ways to improve the performance and to stabilize and control hypersonic vehicles.
CHANDRA X-RAY AND HUBBLE SPACE TELESCOPE IMAGING OF OPTICALLY SELECTED KILOPARSEC-SCALE BINARY ACTIVE GALACTIC NUCLEI. I. NATURE OF THE NUCLEAR IONIZING SOURCES*

Kiloparsec-scale binary active galactic nuclei (AGNs) signal active supermassive black hole (SMBH) pairs in merging galaxies. Despite their significance, unambiguously confirmed cases remain scarce and most have been discovered serendipitously. In a previous systematic search, we optically identified four kpc-scale binary AGNs from candidates selected with double-peaked narrow emission lines at z = 0.1-0.2. Here, we present Chandra and Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging of these four systems. We critically examine and confirm the binary-AGN scenario for two of the four targets, by combining high angular resolution X-ray imaging spectroscopy with Chandra ACIS-S, better nuclear position constraints from WFC3 F105W imaging, and direct starburst estimates from WFC3 F336W imaging; for the other two targets, the existing data are still consistent with the binary-AGN scenario, but we cannot rule out the possibility of only one AGN ionizing gas in both merging galaxies. We find tentative evidence for a systematically smaller X-ray-to-[O III] luminosity ratio and/or higher Compton-thick fraction in optically selected kpc-scale binary AGNs than in single AGNs, possibly caused by a higher nuclear gas column due to mergers and/or a viewing angle bias related to the double-peak narrow-line selection. While our result lends some further support to the general approach of optically identifying kpc-scale binary AGNs, it also highlights the challenge and ambiguity of X-ray confirmation.
Chiral Phosphoramide-Catalyzed Aldol Additions of Ketone Enolates. Preparative Aspects

Trichlorosilyl enolates of ketones (enoxytrichlorosilanes) were demonstrated to be highly reactive aldol addition reagents. Trichlorosilyl enolates of cyclohexanone (E-enolate) and propiophenone (Z-enolate) reacted readily at room temperature with a wide variety of aldehydes to afford aldol addition products in high yield and diastereoselectivity (E → syn, Z → anti). These reactions were shown to be highly susceptible to acceleration by catalytic quantities of chiral phosphoramides. In particular, a phosphoramide derived from (S,S)-stilbenediamine was remarkably effective not only in accelerating the reaction but also in modulating the diastereoselectivity and in providing the aldol addition products in good to excellent enantioselectivity. The diastereoselectivity of the unpromoted process has been interpreted as a consequence of reaction via a pentacoordinate, trigonal bipyramidal (tbp) silicon complex through a boatlike transition structure. The phosphoramide-catalyzed reactions are more complicated an...
Synthesis and characterization of wurtzite-phase copper tin selenide nanocrystals.

A new wurtzite phase of copper tin selenide (CTSe) was discovered, and the resulting nanocrystals were synthesized via a facile solution-phase method. The wurtzite CTSe nanocrystals were synthesized with dodecylamine and 1-dodecanethiol as coordinating solvents and di-tert-butyl diselenide (tBu2Se2) as the selenium source. Specific reaction control (i.e., a combination of 1-dodecanethiol with tBu2Se2) was proven to be critical in order to obtain this new phase of CTSe, which was verified by powder X-ray diffraction and selected area electron diffraction. The wurtzite CTSe nanocrystals possess an optical and electrochemical band gap of 1.7 eV and display an electrochemical photoresponse indicative of a p-type semiconductor.
Head-strictness is not a monotonic abstract property

Abstract A property P of a language is said to be definable by abstract interpretation if there is a monotonic map abs from the domain of standard semantics to an abstract domain A of finite height, and a partition of the abstract domain into parts A P and A non- P , such that any value has property P if and only if abs maps it to an element of A P . Head-strictness is a property of functions over lists which asserts, roughly speaking, that whenever the function looks at some prefix of a list, it looks at every element in that prefix. We prove that head-strictness is not definable by abstract interpretation.
One carbon homologation of halides to benzyl ethers

The preparation of one carbon homologated benzyl ethers from alkyl and aromatic halides is reported. The coupling reaction is rapid and efficient at room temperature.