cssi/SciSciGPT-SciSciNet huggingface dataset:
Mathematical techniques for quantum communication theory

We present mathematical techniques for addressing two closely related questions in quantum communication theory. In particular, we give a statistically motivated derivation of the Bures-Uhlmann measure of distinguishability for density operators, and we present a simplified proof of the Holevo upper bound to the mutual information of quantum communication channels. Both derivations give rise to novel quantum measurements.
An effective lagrangian with broken scale and chiral symmetry IV: Nucleons and mesons at finite temperature

Abstract We study the finite temperature properties of an effective chiral Lagrangian which describes nuclear matter. Thermal fluctuations in both the nucleon and the meson fields are considered. The logarithmic and square root terms in the effective potential are evaluated by expansion and resummation with the result written in terms of the exponential integral and the error function, respectively. In the absence of explicit chiral symmetry breaking a phase transition restores the symmetry, but when the pion has a mass the transition is smooth. The nucleon and meson masses as a functions of density and temperature are discussed.
Counting Semisimple Orbits of Finite Lie Algebras by Genus

Abstract The adjoint action of a finite group of Lie type on its Lie algebra is studied. A simple formula is conjectured for the number of semisimple orbits of a given split genus. This conjecture is proved for type A , and partial results are obtained for other types. For type A a probabilistic interpretation is given in terms of card shuffling.
Concept and model of a piezoelectric structural fiber for multifunctional composites

The use of piezoceramic materials for structural sensing and actuation is a fairly well developed practice that has found use in a wide variety of applications. However, just as advanced composites offer numerous benefits over traditional engineering materials for structural design, actuators that utilize the active properties of piezoelectric fibers can improve upon many of the limitations encountered when using monolithic piezoceramic devices. Several new piezoelectric fiber composites have been developed, however almost all studies have implemented these devices such that they are surface-bonded patches used for sensing or actuation. This paper will introduce a novel active piezoelectric structural fiber that can be laid up in a composite material to perform sensing and actuation, in addition to providing load bearing functionality. The sensing and actuation aspects of this multifunctional material will allow composites to be designed with numerous embedded functions including, structural health monitoring, power generation, vibration sensing and control, damping, and shape control through anisotropic actuation. A one-dimensional micromechanics model of the piezoelectric fiber will be developed to characterize the feasibility of constructing structural composite lamina with high piezoelectric coupling. The theoretical model will be validated through finite element (FE) modeling in ABAQUS. The results will show that the electromechanical coupling of a fiber-reinforced polymer composite incorporating the active structural fiber (ASF) could be more than 70% of the active constituent.
Destruction of the fractional quantum Hall effect by disorder

Abstract I suggest that Hall steps in the fractional quantum Hall effect are physically similar to those in the ordinary quantum Hall effect. This proposition leads to a simple scaling diagram containing a new type of fixed point, which I identify with the destruction of the fractional states by disorder.
Exotica and the confining flux

Abstract Recent developments in Quantum Chromodynamics (QCD) are reviewed on three major topics where nonperturbative gluon excitations of the QCD vacuum and the physical properties of the confining flux play a central role: (1) New lattice results on the spectrum and wave functions of heavy Q Q gluon molecules, known as heavy hybrids, will be discussed. (2) Recent advances on the glueball spectrum in lattice QCD will be presented with some theoretical observations. (3) Progress in our understanding of the nonperturbative internal structure of the confining flux and its excitation spectrum will be reported.
Regiochemical control in intramolecular cyclization of methylene-interrupted epoxydiols.

Methylene-interrupted epoxydiols have multiple regiochemical routes for cyclization. The 5-exo process is the most prevalent under acidic conditions. However, the regioselectivity can be controlled...
Combining the advantages of superconducting MgB2 and CaC6 in one material: suggestions from first-principles calculations

We show that a recently predicted layered phase of lithium monoboride ${\mathrm{Li}}_{2}{\mathrm{B}}_{2}$ combines the key mechanism for strong electron-phonon coupling in ${\mathrm{MgB}}_{2}$ (i.e., interaction of covalent $\mathrm{B}\phantom{\rule{0.3em}{0ex}}\ensuremath{\sigma}$ bands with B bond-stretching modes) with the dominant coupling mechanism in ${\mathrm{CaC}}_{6}$ (i.e., interaction of free-electron-like interlayer states with soft intercalant modes). Yet, surprisingly, the electron-phonon coupling in ${\mathrm{Li}}_{2}{\mathrm{B}}_{2}$ is calculated to be weaker than in either ${\mathrm{MgB}}_{2}$ or ${\mathrm{CaC}}_{6}$. We demonstrate that this is due to the accidental absence of $\mathrm{B}\phantom{\rule{0.3em}{0ex}}\ensuremath{\pi}$ states at the Fermi level in ${\mathrm{Li}}_{2}{\mathrm{B}}_{2}$. In ${\mathrm{MgB}}_{2}$, the $\ensuremath{\pi}$ electrons play an indirect but important role in strengthening the coupling of $\ensuremath{\sigma}$ electrons. Doping ${\mathrm{Li}}_{2}{\mathrm{B}}_{2}$ to restore $\ensuremath{\pi}$ electrons at the Fermi level is expected to lead to a new superconductor that could surpass ${\mathrm{MgB}}_{2}$ in ${T}_{c}$.
Legitimacy, Interest Group Pressures, and Change in Emergent Institutions: The Case of Foreign Investors and Host Country Governments

We offer a simple model of policy making, emphasizing socialization and limits on human cognition to explicate mechanisms of change in emergent (as opposed to established) institutions. Emergent institutions are more susceptible to change, and their opponents may use frames or existing reference points to illustrate inconsistency with prevailing notions of legitimacy. Broader institutional structures and specific organizational characteristics moderate pressure for change. This perspective has novel implications for strategy and policy design.
Congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is a family of autosomal recessive disorders in which there is a deficiency of one of the enzymes necessary for cortisol synthesis. An abnormality in each of the enzymatic activities required for cortisol synthesis has been described. As a result of the disordered enzymatic step, there is decreased cortisol synthesis, increased ACTH via a negative feedback system, overproduction of the hormones prior to the enzymatic step or not requiring the deficient enzyme, and deficiency of the hormones distal to the disordered enzymatic step. Since several of the enzymatic steps are required for sex hormone synthesis by the gonad, a disordered enzymatic step in the gonad resulting in gonadal steroid hormone deficiency may also be present. This chapter presents an overview of all of the enzymatic deficiencies resulting in CAH with the most extensive review of 21-hydroxylase deficiency which is the most common, first described, and most intensively studied of the enzymatic disorders.
New mixing-length model for turbulent high-speed flows

A modification of Prandtl's mixing-length model is presented which takes into account the effects of compressibility on turbulence for high speed flows. A parameter is introduced into the turbulent transport formula which acts like an effective turbulent Schmidt number for mixtures of gases or a turbulent Prandtl number for a homogeneous gas. Results presented for such cases as high Mach number turbulent boundary layer flows over a flat surface, tangential slot injection problems, and shock/turbulent shear-layer and boundary-layer interactions agree well with experimental data.
Preference-directed regulation when ethical environmental policy choices are formed with limited information

Preference-directed regulation (PDR) can supplement traditional environmental policies through frequent regulatory revision (Livermore, Va Environ Law J 25:311–386, 2007). Using original survey data, PDR is operationalized via counterfactual simulations within a limited information discrete choice model. Augmenting individual opinions about one of the three policies at driving environmental outcomes, stakeholders can induce preference switching in favor of or in detriment to a specific policy. The three policies are summarized as: (1) ban; (2) tax; and (3) label. The resulting substitution patterns demonstrate that the extent of preference switching between policies depends on the relative change in individual opinions about a policy. Furthermore, different forms of PDR may be more effective at inducing preference switching in favor of or in detriment to a specific policy.
Gravitational radiation, inspiraling binaries, and cosmology

We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.
Microtext: the design of a microprogrammed finite state search machine for full-text retrieval

The Microtext system represents a new approach to the design and implementation of a full-text retrieval system. The approach is unusual in that it integrates hardware, firmware, and software components in an attempt to provide a solution to the problems involved in processing large files of unformatted textual data. The system is based on a minicomputer specialized for high-speed full-text retrieval, through the use of a finite state search algorithm implemented in firmware.
Remarks on Quantum Transmutation

We want to sketch here a program and a framework along with a few ideas about implementing it (cf. [121]). First we indicate briefly some results of Koelink and Rosengren [402], involving tramsmutation kernels for little q-Jacobi functions. This is modeled in part on earlier work of Koornwinder [414] and others on classical Fourier-Jacobi, Abel, and Weyl transforms, plus formulas in q-hypergeometric functions (see e.g. [401, 404, 412]). Here transmutation refers to intertwining of operators (i.e. QB = BP) and the development gives a q-analysis version of some transforms and intertwinings whose classical versions were embedded as examples in a general theory of transmutation of operators by the author (and collaborators) in [76, 110, 111, 112, 113] (see also the references in these books and papers). It is clear that many of the formulas from the extensive general theory will have a q-analysis version (as in [402]) and the more interesting problem here would seem to be that of phrasing matters entirely in the language of quantum groups and ultimately connecting the theory to tau functions in the spirit indicated below. In this direction we sketch some of the “canonical” development of the author in [110].
Estimating electrical conductivity tensors of biological tissues using microelectrode arrays.

Finding the electrical conductivity of tissue is highly important for understanding the tissue’s structure and functioning. However, the inverse problem of inferring spatial conductivity from data is highly ill-posed and computationally intensive. In this paper, we propose a novel method to solve the inverse problem of inferring tissue conductivity from a set of transmembrane potential and stimuli measurements made by microelectrode arrays (MEA). We first formalize the discrete forward model of transmembrane potential propagation, based on a reaction–diffusion model with an anisotropic inhomogeneous electrical conductivity-tensor field. Then, we propose a novel parallel optimization algorithm for solving the complex inverse problem of estimating the electrical conductivity-tensor field. Specifically, we propose a single-step approximation with a parallel block-relaxation optimization routine that simplifies the joint tensor field estimation problem into a set of computationally tractable subproblems, allowing the use of efficient standard optimization tools. Finally, using numerical examples of several electrical conductivity field topologies and noise levels, we analyze the performance of our algorithm, and discuss its application to real measurements obtained from smooth-muscle cardiac tissue, using data collected with a high-resolution MEA system.
Oxidation of Organotrifluoroborates via Oxone

A method for the oxidation of organotrifluoroborates using Oxone was developed. A variety of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates were converted into the corresponding oxidized products in excellent yields. This method proved to be tolerant of a broad range of functional groups, and in secondary alkyl substrates it was demonstrated to be completely stereospecific.
A stereoselective formal synthesis of (±)-(γ)-lycorane

Abstract Compound 11 , a common intermediate in several syntheses of (±)-γ-lycorane, was prepared, from commercially available N -triisopropylsilyl pyrrole, in 13 steps and overall 34% yield. The key step of the synthesis involved the diastereoselective hydrogenation of a substituted pyrrole ring.
On S. Mazur's problems 8 and 88 from the Scottish Book

The paper discusses Problems 8 and 88 posed by Stanislaw Mazur in the Scottish Book. It turns out that negative solutions to both problems are immediate consequences of the results of Section 5 of my paper "Estimates of functions of power bounded operators on Hilbert spaces", J. Operator Theory 7 (1982), 341-372. We discuss here some quantitative aspects of Problems 8 and 88 and give answers to open problems discussed in a recent paper by Pelczynski and Sukochev.
U duality covariant M theory cosmology

Abstract A manifestly U-duality covariant approach to M-theory cosmology is developed and applied to cosmologies in dimensions D =4,5. Cosmological properties such as expansion powers and Hubble parameters turn out to be U-duality invariant in certain asymptotic regions. U-duality transformations acting on cosmological solutions, on the other hand, shift the transition time between two asymptotic regions and determine the details of the transition. Moreover, in D =5, we show that U-duality can map expanding negative and positive branch solutions into each other.
Biomedical applications of dendrimers: a tutorial

Since their development in the mid-80s, dendrimers have become prominent synthetic macromolecules in the field of biomedical science. This tutorial review begins by discussing pertinent background information about dendrimers, focusing on their behavior in solution, how they are synthesized and what advantages they have over linear polymers. Then the focus of the review shifts to the biomedical applications of dendrimers, including their use in drug delivery, tissue engineering, gene transfection, and contrast enhancement for magnetic resonance imaging. This tutorial review is written for first-year graduate students or senior undergraduates and “asks” and “answers” many of the questions that arise in our first discussions of dendrimers.
The Pattern of Migration With Variable Migration Cost

In this paper the role of migrant networks in determining patterns of out-migration is examined. Conditions under which migration equilibrium may permit multiple steady states are identified. The analysis discusses instances where migration generates its own demand and explains differences in migration propensities across potential sources of out-migration.
Reverse-wave suppressor mirror effects on cw HF unstable ring laser performance.

The effect of a reverse-wave suppressor (RWS) mirror on the performance of a multiline cw HF ring laser was measured and theoretically discussed. Forward-wave far-field brightness was found to be very sensitive to the tilt of a conventional RWS mirror, being reduced by a factor of 2 for a 200-μrad RWS tilt. An aberrated mirror was found to reduce this tilt senstivity by nearly an order of magnitude. Also discussed is a possible mechanism whereby the tilt of the conventional RWS mirror reinforced a higher-order mode in the forward-wave output, yet the tilt of the aberrated mirror did not.
Rhodium(II)-catalyzed enantioselective C-H functionalization of indoles.

A catalytic, enantioselective method for the C−H functionalization of indoles by diazo compounds has been achieved. With catalytic amounts of Rh2(S-NTTL)4, the putative Rh−carbene intermediates from α-alkyl-α-diazoesters react with indoles at C(3) to provide α-alkyl-α-indolylacetates in high yield and enantioselectivity. From DFT calculations, a mechanism is proposed that involves a Rh−ylide intermediate with oxocarbenium character.
An ‘almost all versus no’ dichotomy in homogeneous dynamics and Diophantine approximation

Let Y 0 be a not very well approximable m × n matrix, and let $${\mathcal {M}}$$ be a connected analytic submanifold in the space of m × n matrices containing Y 0. Then almost all $${Y \in \mathcal {M}}$$ are not very well approximable. This and other similar statements are cast in terms of properties of certain orbits on homogeneous spaces and deduced from quantitative nondivergence estimates for‘quasi-polynomial’ flows on the space of lattices.
Enhancing current density using vertically oriented organic photovoltaics

We report a new organic photovoltaics (OPV) design, a wrapped OPV, which can circumvent both challenges of short exciton diffusion length [1], and low charge carrier mobility [2] of organic semiconductors by orienting the OPV vertically, to capture; manage; guide and use all incident photons and therefore, generate higher current. Resonant light, on being transmitted into a wrapped OPV, makes multiple passes through the photoactive layer and is absorbed completely, thus achieving benefits of thick photoactive layer while maintaining its ultra-thin thickness requirement. The current density generated from a wrapped OPV is twice than that generated by a similar OPV with flat orientation.
Fractional calculus in the transient analysis of viscoelastically damped structures

Fractional calculus is used to model the viscoelastic behavior of a damping layer in a simply supported beam. The beam is analyzed by using both a continuum formulation and a finite element formulation to predict the transient response to a step loading. The construction of the finite element equations of motion and the resulting nontraditional orthogonality conditions for the damped mode shapes are presented. Also presented are the modified forms of matrix iteration required to calculate eigenvalues and mode shapes for the damped structure. The continuum formulation, also incorporating the fractional calculus model, is used to verify the finite element approach. The location of the poles (damping and frequency) are found to be in satisfactory agreement, as are the modal amplitudes for the first several modes.
The effective temperature distribution function of cataclysmic variable white dwarfs

With the recent detection of direct white dwarf photospheric radiation from certain cataclysmic variables in quiescent (low accretion) states, important implications and clues about the nature and long-term evolution of cataclysmic variables can emerge from an analysis of their physical properties. Detection of the underlying white dwarfs has led to a preliminary empirical CV white dwarf temperature distribution function and, in a few cases, the first detailed look at a freshly accreted white dwarf photosphere. The effective temperatures of CV white dwarfs plotted versus orbital period for each type of CV appears to reveal a tendency for the cooler white dwarf primaries to resisde in the shorter period systems. Possible implications are briefly discussed.
Possible explanation of the pseudogap in high-temperature cuprates

A concept describing the origin and some properties of the ``pseudogap phase'' of high-${T}_{c}$ superconducting cuprates is proposed based on the author's idea about resonant tunneling connection between the ${\mathrm{CuO}}_{2}$ layers. The superconducting critical temperature in this picture is defined at low doping by establishment of a three-dimensional phase correlation between the layers, and at high doping by destruction of a d-wave superconductivity by disorder. The result is a nonmonotonic behavior of ${T}_{c}$ with doping. The pseudogap phase is analyzed qualitatively on the basis of the recently discovered existence of vortices in this phase and one-dimensional fluctuations due to extended saddle points (``hot spots'').
A Synthesis of the 4-Alkylamino-2,4-Dideoxy-l-threo-pentopyranose Components of the Calicheamicins and Esperamicins

Abstract A general synthetic approach to enantiomerically pure 4-substituted 2,4-dideoxypentopyranosides has been developed which provides access to the 4-alkylamino-2,4-dideoxy-L-threo-pentopyranose components of the calicheamicins and esperamicins.
An Improved Synthetic Route to Aminoxypropylamine (APA) and Related Homologs

Abstract Aminoxypropylamine (APA) has been found to be a potent inhibitor of several enzymatic pathways involved in the biosynthesis of the naturally occurring polyamines putrescine, spermidine, and spermine. This report describes a convenient, three-step synthesis of APA, as well as its ethyl and butyl homologs, utilizing starting materials and intermediates useful in the preparation of other related aminoxyalkylamines.
Blue Stragglers in Low-Luminosity Star Clusters*

We examine the blue straggler populations of 13 low-luminosity (M -6) globular clusters and two old open clusters. These clusters test blue straggler formation in environments intermediate between higher luminosity (and usually higher density) clusters and the Galactic field. The anticorrelation between the relative frequency of blue stragglers (FBSS = NBSS/NHB) and cluster luminosity continues to the lowest luminosity clusters, which have frequencies meeting or exceeding that of field stars. In addition, we find that the anticorrelation between straggler frequency and central density disappears for clusters with density less than about 300 LV, ☉ pc-3, although this appears to be an artifact of the correlation between cluster luminosity and central density. We argue on observational (wide, eccentric binaries containing blue stragglers in M67, and the existence of very bright stragglers in most of the clusters in our sample) and theoretical grounds that stellar collisions still produce a significant fraction of the blue stragglers in low-luminosity star clusters, due to the long-term survival of wide binaries.
Rotor Wake Mixing Effects Downstream of a Compressor Rotor

An experimental study of rotor wake was conducted in the trailing-edge and near-wake regions of a moderately loaded compressor rotor blade using a rotating tri-axial hot-wire probe in a rotating frame of reference. The flow-field was surveyed very close to the trailing-edge as well as inside the annulus and hub-wall boundary layers. 9 refs.
Right Limits and Reflectionless Measures for CMV Matrices

We study CMV matrices by focusing on their right-limit sets. We prove a CMV version of a recent result of Remling dealing with the implications of the existence of absolutely continuous spectrum, and we study some of its consequences. We further demonstrate the usefulness of right limits in the study of weak asymptotic convergence of spectral measures and ratio asymptotics for orthogonal polynomials by extending and refining earlier results of Khrushchev. To demonstrate the analogy with the Jacobi case, we recover corresponding previous results of Simon using the same approach.
The Star Formation History of NGC 6822

Images of five fields in the Local Group dwarf irregular galaxy NGC 6822 obtained with the Hubble Space Telescope in the F555W and F814W filters are presented. Three of the fields lie mostly within the central bar of NGC 6822, where most of the sites of current star formation are concentrated, while two other fields sample more of the outer regions of the galaxy. Photometry for the stars in these images was extracted using the point-spread function–fitting program HSTPHOT/MULTIPHOT. The resulting color-magnitude diagrams reach down to V ≈ 26, a level well below the red clump, and were used to solve quantitatively for the star formation history of NGC 6822. Assuming that stars began forming in this galaxy from low-metallicity gas and that there is little variation in the metallicity at each age, the distribution of stars along the red giant branch is best fitted with star formation beginning in NGC 6822 12–15 Gyr ago. The best-fitting star formation histories for the old and intermediate-age stars are similar among the five fields and show a constant or somewhat increasing star formation rate from 15 Gyr ago to the present except for a possible dip in the star formation rate from 3 to 5 Gyr ago. The main differences among the five fields are in the higher overall star formation rate per area in the bar fields, as well as in the ratio of the recent star formation rate to the average past rate. These variations in the recent star formation rate imply that stars formed within the past 0.6 Gyr are not spatially very well mixed throughout the galaxy. The star formation histories in conjunction with a galaxy evolution code are used to infer the evolution of the integrated absolute magnitude of NGC 6822 as a function of look-back time and redshift. The results indicate that galaxies with star formation histories similar to that determined for NGC 6822 would have an absolute magnitude of MB = -15.7 at a redshift z = 0.6, well below the detection limit of the current redshift surveys, and therefore are most likely not contributing to the evolving galaxy population detected in deep redshift surveys.
Radical aromatic substitution via atom-transfer addition

Abstract New methodology for radical aromatic substitution has been developed involving the addition of electron-deficient radicals to unprotected pyrroles and indole. This non-oxidative process is presumed to be occurring via atom-transfer addition of suitable organoiodides and bromides with subsequent non-radical elimination of HI or HBr, respectively. The process also occurs under stannane-free conditions.
A New Color-Magnitude Diagram for Palomar 11

We present new photometry for the Galactic thick-disk globular cluster Palomar 11 extending well past the main-sequence turnoff in the V and I bands. This photometry shows noticeable, but depleted, red giant and subgiant branches. The difference in magnitude between the red horizontal branch (red clump) and the subgiant branch is used to determine that Palomar 11 has an age of 10.4 ± 0.5 Gyr. The red clump is used to derive a distance d⊙ = 14.3 ± 0.4 kpc and a mean cluster reddening of E(V - I) = 0.40 ± 0.03. There is differential reddening across the cluster, of order δE(V - I) ~ 0.07. The color-magnitude diagram of Palomar 11 is virtually identical to that of the thick-disk globular cluster NGC 5927, implying that these two clusters have a similar age and metallicity. Palomar 11 has a slightly redder red giant branch than 47 Tuc, implying that Palomar 11 is 0.15 dex more metal-rich, or 1 Gyr older, than 47 Tuc. Ca II triplet observations, such as those of Rutledge and coworkers, favor the hypothesis that Palomar 11 is the same age as 47 Tuc, but slightly more metal-rich.
Calculation of electronic properties of amorphous alloys

Abstract The application of the locally-self-consistent-multiple-scattering (LSMS) method to amorphous alloys is described. The LSMS algorithm is optimized for the Intel XP/S-150, a multiple-instruction-multiple-data parallel computer with 1024 nodes and 2 compute processors per node. The electron density at each site is determined by solving the multiple scattering equation for atoms within a specified distance of the atom under consideration. Because this method is carried out in real space, it is ideal for treating amorphous alloys. The code was adapted to the calculation of the electronic properties of amorphous alloys. In these calculations, the potentials in the atomic sphere approximation were determined self-consistently at each site, unlike previous calculations where the potentials were determined self-consistently at an average site. With these self-consistent potentials, the electronic properties of various amorphous alloy systems were then calculated. The calculated total electronic densities of states are presented for amorphous Ni 80 P 20 and Ni 40 Pd 40 P 20 with 300 atoms in a supercell.
Diastereoselective 1,2- and 1,3-diol formation via oxygen-centered radical cyclizations

Abstract Allylic and homoallylic alkoxycarbonyloxyl radicals, produced in chain reactions of 3-hydroxy-4-methylthiazole-2(3 H )-thione carbonates, cyclize to give, ultimately, 1,2- and 1,3-diol carbonates in fair to good yield and, in some cases, high diastereoselectivity.
Reducing Lateral Vibrations of a Rotor Passing Through Critical Speeds by Acceleration Scheduling

A method is presented for reducing the lateral response of an imbalanced rotor accelerating or decelerating through its first lateral bending critical speed by using a variable acceleration rate. A lumped parameter model along with a numerical integration scheme is used to simulate the response of a simply supported, single disk rotor during fast acceleration and deceleration through critical speed. The results indicate that the maximum response and/or the total vibrational energy ofa rotor passing through the critical speed can be reduced significantly by using a variable acceleration schedule. That is, reducing the acceleration rate after the nominal critical speed is passed. These predictions were verified experimentally for a single disk rotor.
Intercepting moving targets: A little foresight helps a lot

Behavioral studies suggest that humans intercept moving targets by maintaining a constant bearing angle (CBA). The purely feedback-driven CBA strategy has been contrasted with the strategy of predicting the eventual time and location of the future interception point. This study considers an intermediate anticipatory strategy of moving so as to produce a CBA a short duration into the future. Subjects controlled their speed of self-motion along a linear path through a simulated environment to intercept a moving target. When targets changed speed midway through the trial in Experiment 1, subjects abandoned an ineffective CBA strategy in favor of a strategy of anticipating the most likely change in target speed. In Experiment 2, targets followed paths of varying curvature. Behavior was inconsistent with both the CBA and the purely predictive strategy. To investigate the intermediate anticipatory strategy, human performance was compared with a model of interceptive behavior that, at each time-step t, produced the velocity adjustment that would minimize the change in bearing angle at time t + ∆t, taking into account the target’s behavior during that interval. Values of ∆t at which the model best fit the human data for practiced subjects varied between 0.5 and 3.5 s, suggesting that actors adopt an anticipatory strategy to keep the bearing angle constant a short time into the future.
A simple enantioselective synthesis of serratenediol.

A short synthesis of serratenediol is described, which involves a number of powerful key steps including (1) catalytic enantioselective syntheses of the phenyl sulfone and acylsilane shown above, (2) their coupling, and (3) further stereoselective cationic cyclizations.
A novel reagent for the synthesis of myo-inositol phosphates: N,N-diisopropyl dibenzyl phosphoramidite

Abstract It has been found that partially protected inositols are phosphorylated in near quantitative yields by use of N , N -diisopropyl dibenzyl phosphoramidite, 1-H-tetrazole and MCPBA in CH2Cl2. Subsequent hydrogenolysis of the resulting perbenzylated products gives the corresponding free inositol phosphates in quantitative yields without tedious ion exchange chromatography.
Japan and Hong Kong Exchange-Traded Funds (ETFs): Discounts, Returns, and Trading Strategies

Foreign exchange-traded funds (ETFs) trade on U.S. exchanges but provide broad exposure to foreign markets. ETFs are designed to minimize the deviation between price and value of the underlying securities. However, nonoverlapping trading hours between the United States and many foreign markets inhibit this mechanism. The data for Japan and Hong Kong iShares show that deviations exist between the ETF price and the value of the underlying securities. The deviations are positively related to subsequent ETF returns creating potential profit opportunities. A simple trading rule based on this observation produces impressive gross returns when compared to a buy-and-hold strategy.
EL-labelings, supersolvability and 0-Hecke algebra actions on posets

It is well known that if a finite graded lattice of rank n is supersolvable, then it has an EL-labeling where the labels along any maximal chain form a permutation. We call such a labeling an Sn EL-labeling and we show that a finite graded lattice of rank n is supersolvable if and only if it has such a labeling. We next consider finite graded posets of rank n with 0' and 1' that have an Sn EL-labeling. We describe a type A 0-Hecke algebra action on the maximal chains of such posets. This action is local and gives a representation of these Hecke algebras whose character has characteristic that is closely related to Ehrenborg's flag quasisymmetric function. We ask what other classes of posets have such an action and in particular we show that finite graded lattices of rank n have such an action if and only if they have an Sn EL-labeling.
Synthesis of enantiomerically pure cis-2,4-disubstituted piperidines: extension of chiral homoenolate alkylations toward the preparation of nitrogen heterocycles

Abstract Enantiomerically pure cis -2,4-disubstituted piperidines were synthesized from chiral thiolactam 2 in six steps via a highly diastereoselective homoenolate alkylation which set the stereochemistry at the C4 carbon. In addition, two cleavage methods were used to cleave the lactam to the desired piperidines with a high level of diastereoselection at the newly created C2 stereocenter.
Extended Torelli Map to the Igusa Blowup in Genus 6, 7, and 8

It was conjectured in [Namikawa 73] that the Torelli map associating to a curve its Jacobian extends to a regular map from the Deligne–Mumford moduli space of stable curves to the (normalization of the) Igusa blowup . A counterexample in genus g=9 was found in [Alexeev and Brunyate 11]. Here, we prove that the extended map is regular for all g⩽8, thus completely solving the problem in every genus.
Autocatalytic Water Dissociation on Cu(110) at Near Ambient Conditions

Autocatalytic dissociation of water on the Cu(110) metal surface is demonstrated on the basis of X-ray photoelectron spectroscopy studies carried out in situ under near ambient conditions of water vapor pressure (1 Torr) and temperature (275−520 K). The autocatalytic reaction is explained as the result of the strong hydrogen-bond in the H2O−OH complex of the dissociated final state, which lowers the water dissociation barrier according to the Bronsted−Evans−Polanyi relations. A simple chemical bonding picture is presented which predicts autocatalytic water dissociation to be a general phenomenon on metal surfaces.
Oligopolistic Competition and Economic Geography

This paper studies a general equilibrium model of economic geography in which firms engage in oligopolistic competition. This framework is conducive to analytic results. With increasing returns, oligopolistic competition leads to inter-industry trade between regions rather than intra-industry trade. The choice of appropriate technology is a channel of concentration of industries.
Real-Time PCR: An Effective Tool for Measuring Transduction Efficiency in Human Hematopoietic Progenitor Cells

Accurate measurement of gene transfer into hematopoietic progenitor cells is an essential prerequisite for assessing the utility of gene therapy approaches designed to correct hematologic defects. We developed a reliable method to measure transduction efficiency at the level of the progenitor cell with real-time polymerase chain reaction (PCR) analysis of individual progenitor-derived colonies. We hypothesized that this method would demonstrate better sensitivity and specificity than are currently achievable with conventional PCR. An oncoretroviral vector containing the enhanced green fluorescent protein was used to transduce human CD34+ cells derived from bone marrow or granulocyte-colony-stimulating factor-mobilized peripheral blood. Progenitor assays were set up and colonies plucked after visualization by fluorescence microscopy. By analyzing microscopically identified fluorescent samples and nontransduced samples, we calculated an overall sensitivity and specificity of 90.2 and 95.0%, respectively. Real-time PCR had higher specificity and sensitivity than conventional PCR as analyzed by generalized linear models (P = 0.002 and P = 0.019, respectively). In conclusion, we found real-time PCR to have superior sensitivity and specificity compared to conventional PCR in determining transduction efficiency of hematopoietic progenitor cells.
On the Design of Reliable Boolean Circuits That Contain Partially Unreliable Gates

We investigate a model of gate failure for Boolean circuits in which a faulty gate is restricted to output one of its input values. For some types of gates, the model, which we call theshort-circuit model of gate failure, is weaker than the traditionalvon Neumann modelin which faulty gates always output precisely the wrong value. Our model has the advantage that it allows us to design Boolean circuits that can tolerate worst-case faults, as well as circuits that have arbitrarily high success probability in the case of random faults. Moreover, the short-circuit model captures a particular type of fault that commonly appears in practice, and it suggests a simple method for performing posttest alterations to circuits that have more severe types of faults. A variety of bounds on the size of fault-tolerant circuits are proved in the paper. Perhaps, the most important is a proof that anyk-fault-tolerant circuit for any input-sensitive function using any type of gates (even arbitrarily powerful, multiple-input gates) must have size at least?(klogk/loglogk). Obtaining a tight bound on the size of a circuit for computing the AND of two values if up tokof the gates are faulty is one of the central questions left open in the paper.
Pseudodifferential Operators with Rough Symbols

In this work, we develop L p boundedness theory for pseudodifferential operators with rough (not even continuous in general) symbols in the x variable. Moreover, the B(L p ) operator norms are estimated explicitly in terms of scale invariant quantities involving the symbols. All the estimates are shown to be sharp with respect to the required smoothness in the ξ variable. As a corollary, we obtain L p bounds for (smoothed out versions of) the maximal directional Hilbert transform and the Carleson operator.
Decisionmaking organizations with acyclical information structures

An analytical model of a team of well-trained human decisionmakers executing a well-defined decisionmaking task is presented. Each team member is described by a two-stage model consisting of a situation assessment (SA) and a response selection (RS) stage. An information theoretic framework is used, in which bounded rationality is modelled as a constraint on the total rate of internal processing by each decisionmaker. Optimising and satisfying strategies are derived and their properties analysed in terms of organisational performance and individual workload. The results are applied to the analysis of two three-person organisational designs.
THREE-BODY DECAYS OF SELECTRONS AND SMUONS IN LOW-ENERGY SUPERSYMMETRY BREAKING MODELS

Abstract In models with low-energy supersymmetry breaking, it is well known that charged sleptons can be significantly lighter than the lightest neutralino, with the gravitino and lighter stau being the lightest and next-to-lightest supersymmetric particles respectively. We give analytical formulas for the three-body decays of right-handed selectrons and smuons into final states involving a tau, a stau, and an electron or muon, which are relevant in this scenario. We find that the three-body decays dominate over much of the parameter space, but the two-body decays into a lepton and a gravitino can compete if the three-body phase space is small and the supersymmetry breaking scale (governing the two-body channel) is fairly low. We study this situation quantitatively for typical gauge-mediated supersymmetry breaking model parameters. The three-body decay lengths are possibly macroscopic, leading to new unusual signals. We also analyze the final-state energy distributions, and briefly assess the prospects for detecting these decays at CERN LEP2 and other colliders.
Light and life: Niels Bohr's legacy to contemporary biology

On August 15, 1932 Niels Bohr gave the opening address of the International Congress on Light Therapy held in Copenhagen. Bohr's title was "Light and Life," and his purpose was to draw attention to the epistemological implications for the life sciences of the fundamental changes that the quantum theory had brought to the conception of natural law (Bohr 1933). He thought that these changes, which extend to the very idea of the nature of scientific explanation, were important not only for a full appreciation of the new situation brought to physics by the quantum theory. According to Bohr, these developments had also created an entirely new background for viewing the problems of biology, especially as concerns "our views on the position of living organisms in the realm of natural science." In particular, Bohr proposed that the notion of complementarity, which he had first presented 5 years earlier at the International Congress of Physics in Como, is relevant also for the physiological and psychological aspects of life. Bohr began his address by stating what is nowadays stigmatized as the "reductionist" credo, namely that the subtle character of the riddle of life notwithstanding, any scientific explanation of biological phenomena "necessarily must consist of reducing the description of more complex phenomena to that of simpler ones." But, Bohr continued, the discovery of an essential limitation of the mechanical description of natural phenomena, as revealed by the recent development of the atomic theory, has lent new interest to the old problem of how far the program of reductive biological explanations can be carried. Bohr then presented a brief historical account of the rise of the quantum theory in connection with the study of light, which he thought "is perhaps the least complex of all physical phenomena." Yet, it turned out that despite its lack of complexity, the phenomenon of light cannot be given a coherent mechanical explanation, inasmuch as from the viewpoint of classical physical theories, "the quantum of action . . . must be considered as an irrational notion." The spatial continuity of light propagation, on the one hand, and the atomicity of light effects on the other hand, must, therefore, be considered as complementary aspects of one reality, in the sense that each expresses an important feature of the phenomena of light. Those aspects are complementary, because, although they are conceptually irreconcilable from a mechanical point of view, they can never be shown to be in direct, or empirical, contradiction. The reason for this is that any closer analysis of either the wave aspect or the particle aspect of light demands mutually exclusive observational arrangements.
Dimerization of (+)-Myrmicarin 215B. A Potential Biomimetic Approach to Complex Myrmicarin Alkaloids

The acid promoted diastereoselective dimerization of myrmicarin 215B is described. The reactivity of these sensitive alkaloids, structural assignment, and a possible mechanism for the observed dimerization is discussed. These finding raise the intriguing possibility of the synthesis of the highly sensitive myrmicarin alkaloids based on a strategy involving the direct dimerization of functional tricyclic myrmicarin derivatives.
Atom transfer cyclization of simple hexenyl iodides. A caution on the use of alkenyl iodides as probes for the detection of single electron transfer processes

Abstract The trialkyltin initiated isomerization of 1-iodo-5-hexene to (iodomethyl)cyclopentane is reported. Rapid and reversible iodine atom transfer between alkyl radicals is the key chain transfer step. The results suggest an important caution in the use of hexenyl iodides as SET probes: a good mechanism exists whereby the yield of rearranged products may be much greater than the amount of radicals produced by the reaction under study!
Rayleigh-Taylor Instabilities in Young Supernova Remnants Undergoing Efficient Particle Acceleration

We employ hydrodynamic simulations to study the effects of high shock compression ratios, as expected for fast shocks with efficient particle acceleration, on the convective instability of driven waves in supernova remnants. We find that the instability itself does not depend significantly on the compression ratio, σ, with the growth rates and the width of the mixing region at saturation being comparable for the range of ratios we studied; 4 ≤ σ ≤ 21. However, because the width of the interaction region between the forward and reverse shocks can shrink significantly with increasing σ, we find that convective instabilities can reach all the way to the forward shock front if compression ratios are high enough. Thus, if supernova blast waves accelerate particles efficiently, we expect the forward shock to be perturbed with small-amplitude, small-wavelength bumps and to find clumps and filaments of dense ejecta material in the vicinity of the shock. In addition and in contrast to situations in which σ ≤ 4, any enhancement of the radial magnetic field from Rayleigh-Taylor instabilities will also extend all the way to the shock front, and this may help explain the slight dominance of radial fields long seen in polarization measurements of young remnants like Tycho.
Jupiter, Saturn, and the Edge of Chaos

Abstract When Saturn's orbital elements are slightly changed from their present values, the motion of the jovian planets enters a large, robustly chaotic zone associated with the 2:5 mean-motion near-resonance between Jupiter and Saturn. The transition to chaos is through large increases in the secular frequency associated with Saturn's perihelion, while the other secular frequencies do not change appreciably. The chaotic zone is closer in the orbital elements' phase space to their current values than the range taken on by these values. It is plausible, therefore, to suspect that passages through such chaotic zones did occur throughout the history of the Solar System.