cssi/SciSciGPT-SciSciNet huggingface dataset:
Helicopter Vibration Reduction Using Discrete Controllable-Stiffness Devices at the Rotor Hub

The present study demonstrates that optimal multi-cyclic stiffness variations of discrete controllable stiffness devices in the rotor blade root region can reduce the 4/rev vibratory hub loads of a four-bladed hingeless rotor helicopter. The controllable stiffness devices (flap, lag, and torsion devices) are modeled as discrete springs whose stiffness coefficients can be varied, and a gradient-based optimization scheme is used to determine optimal multi-cyclic device stiffness variations that minimize a composite index comprising of all six components of vibratory hub loads. Multi-cyclic stiffness variations of the flap and lag devices are most influential, and when optimal 2/rev and 3/rev stiffness variations of these devices were used in combination the vibratory hub drag force was practically eliminated and the vibratory hub side force was reduced by 55%. No significant detrimental effects were observed on the first through the fifth harmonics of the vibratory blade root loads. Multi-cyclic (3/rev and 4/rev) stiffness variations of the torsion device produced only small reductions in the 4/rev hub vertical force. Multi-cyclic stiffness variations of the flap and lag devices were seen to be effective in reducing hub vibration even when there were changes in fundamental rotor properties such as the flap, lag, and torsion stiffness of the root (flexure) element, and the cruise speed.
Effect of short-term hormone replacement therapy on left ventricular mass and contractile function

Objective: To determine the effect of hormone replacement therapy (HRT) on cardiac structure and function and whether these changes are related to changes in blood volume. Design: Open-label pilot study. Setting: Academic medical center. Patient(s): Eighteen healthy postmenopausal women. Intervention(s): We administered medroxyprogesterone acetate orally, 5 mg/d for 2 months followed by 2 months of oral sequential 17β-estradiol, 1 mg/d plus medroxyprogesterone acetate, 10 mg/d for the last 12 days of each month. Main Outcome Measure(s): Cardiac output, stroke volume, heart rate, end diastolic volume, end systolic volume, ejection fraction, and left ventricular mass were measured by echocardiography; blood and plasma volumes were measured using 125I-albumin dilution. Result(s): Cardiac output, stroke volume, left ventricular mass, end diastolic volume, and ejection fraction increased by 12.8%, 11.7%, 9.4%, 7.2%, and 10.9%, respectively, by 16 weeks. End systolic volume decreased, whereas heart rate was unaffected. There was a significant increase in blood volume (5.2%) and plasma volume (4.8%) from baseline during treatment, which could explain the increased cardiac output but not the increased ejection fraction. Conclusion(s): Hormone replacement therapy causes modest but significant increases in cardiac output, ejection fraction, and left ventricular mass. These pilot data suggest a direct myocardial effect of HRT that is preload independent.
Quantum evolution of the disoriented chiral condensates

Abstract We study the dynamics of the chiral phase transition expected during the expansion of the quark-gluon plasma produced in a high energy hadron or heavy ion collision, using the O (4) linear sigma model in the mean field approximation. Imposing boost invariant initial conditions at an initial proper time τ 0 and starting from an approximate equilibrium configuration, we investigate the possibility of formation of disoriented chiral condensate during the expansion. In order to create large domains of disoriented chiral condensates low-momentum instabilities have to last for long enough periods of time. Our simulations show no instabilities for an initial thermal configuration. For some of the out-of-equilibrium initial states studied, the fluctuation in the number of particles with low transverse momenta become large at late proper times.
THE DEMAND FOR ABSTRACT TRANSPORT MODES: THEORY AND MEASUREMENT†

A variety of techniques has been employed in estimating statistical relationships which might be used to predict the amount of travel that will take place at some future time. Some of these attempts involve the formulation of traditional demand functions according to the dictates of a priori economic theorizing; others depend upon careful stratification of the population and subsequent pragmatic extrapolation of travel propensities observed on the basis of direct samples of the various strata. The basic purposes of this paper are (a) to make a theoretical contribution to the study of travel demand and (b) to make a contribution to the estimation and measurement of demand which, in some sense, minimizes the effect of incompleteness of data. The context of the paper is somewhat speculative in that the ideas expressed here have not been fully tested on a variety of data.
Group Actions on Central Simple Algebras

Abstract Let G be a group, F a field, and A a finite-dimensional central simple algebra over F on which G acts by F-algebra automorphisms. We study the subalgebras and ideals of A which are preserved by the group action. We prove a structure theorem and two classification theorems for invariant subalgebras under suitable hypotheses on A. We illustrate these results in the case of compact connected Lie groups and give some other applications. We also classify invariant ideals.
Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

We analyze several possibilities for precisely measuring electronic transitions in atomic helium by the direct use of phase-stabilized femtosecond frequency combs. Because the comb is self-calibrating and can be shifted into the ultraviolet spectral region via harmonic generation, it offers the prospect of greatly improved accuracy for UV and far-UV transitions. To take advantage of this accuracy an ultracold helium sample is needed. For measurements of the triplet spectrum a magneto-optical trap (MOT) can be used to cool and trap metastable 2 3 S state atoms. We analyze schemes for measuring the two-photon 2 3 S → 4 3 S interval, and for resonant two-photon excitation to high Rydberg states, 2 3 S → 3 3 P → n 3 S, D. We also analyze experiments on the singlet-state spectrum. To accomplish this we propose schemes for producing and trapping ultracold helium in the 1 1 So r 2 1 S state via intercombination transitions. A particularly intriguing scenario is the possibility of measuring the 1 1 S → 2 1 S transition with extremely high accuracy by use of two-photon excitation in a magic wavelength trap that operates identically for both states. We predict a "triple magic wavelength" at 412 nm that could facilitate numerous experiments on trapped helium atoms, because here the polarizabilities of the 1 1 S, 2 1 Sa nd 2 3 S states are all similar, small, and positive.
Limiting Performance Characteristics of Steady-State Systems

The problem of determining the limiting (or absolute optimum) performance of mechanical systems subject to steady-state loadings is considered. By replacing portions of a system by generic forces which can represent any configuration, the limiting performance characteristics of the system can be found using mathematical programming techniques. For the class of problems treated here, both performance index and constraints are composed of system response variables, such as displacements, velocities, and accelerations. Details of an efficient linear programming formulation of the problem are presented. In spite of the linear programming solution, no linearity restrictions are placed on the generic forces. Several examples are included.
Prediction of Critical Temperatures and Pressures of Industrially Important Organic Compounds from Molecular Structure

Quantitative−structure property relationships methods are used to develop mathematical models to predict critical temperatures and pressures of a diverse set of organic compounds taken from the Design Institute for Physical Property Data (DIPPR) database. Each compound is represented with calculated molecular structure descriptors that encode its topological, electronic, geometrical, and other features. Subsets of descriptors are selected with simulated annealing and genetic algorithms. Models to predict the critical properties are constructed using multiple linear regression analysis and computational neural networks with errors comparable to the experimental errors of the critical property data.
Conversion of aromatic aldehydes to gem-dichlorides using boron trichloride. A new highly efficient method for preparing dichloroarylmethanes

Abstract The chlorination of aromatic aldehydes with boron trichloride in hexane under reflux conditions produces the corresponding dichloromethyl derivatives in excellent yields.
Tuning a double quantum well Fermi surface with in-plane magnetic fields

Abstract A double quantum well (QW) subject to in-plane magnetic fields B∥ has the dispersion curves of its two QWs shifted in k-space. When the QWs are strongly coupled, an anticrossing and partial energy gap occur, yielding a tunable multi-component Fermi surface. We report measurements of the resultant features in the conductance, the capacitive density of states and giant deviations in the cyclotron effective masses.
Measuring Information Diffusion in an Online Community

Measuring peer influence in social networks is an important business and policy question that has become increasingly salient with the development of globally interconnected information and communication technology networks. However, in spite of the new data sources available today, researchers still face many of the same measurement challenges that have been present in the literature for over four decades: homophily, reflection and selection problems, identifying the source of influence, and determining preexisting knowledge. The goal of this paper is to develop an empirical approach for measuring information diffusion and discovery in online social networks that have these measurement challenges. We develop such an approach and apply it to data collected from 4,000 users of an online music community. We show that peers on such networks significantly increase music discovery. Moreover, we demonstrate how future research can use this method to measure information discovery and diffusion using data from other online social networks.
Some highlights from the development and use of bulky monodentate ligands

Abstract The development of bulky monodentate alkoxide, chalcogenolate (ER, E = S, Se or Te), amide, pnictide (ER2 = N, P, As), alkyl, aryl and silyl ligands is briefly surveyed. These ligands have played a key role in the advancement of the modern organometallic and inorganic chemistry of all the major blocks (s, p, d, and f) of the periodic table. Most importantly, they have permitted numerous new classes of compounds to be isolated and studied. The investigation of steric effects induced by these ligands has led to, inter alia, transition metal alkylidene and alkylidyne complexes, room temperature cleavage of dinitrogen, and a wide range of transition metal and lanthanide complexes with two or three coordination. In addition, their use has sparked a revolution in main group chemistry which has led to the isolation of stable species with bonds and/or oxidation states hitherto unknown in stable compounds.
Rethinking the Role of Fiscal Policy

As recently as two years ago there was a widespread consensus among economists that fiscal policy is not useful as a countercyclical instrument. Now governments in Washington and around the world are developing massive fiscal stimulus packages, supported by a wide range of economists in universities, governments, and businesses. Why has this change occurred? What are the principles for designing a potentially useful fiscal stimulus? And what will happen if the current fiscal stimulus fails?
Accessing the Synthetic Chemistry of Radical Ions

Organic reactions involving radical cation and radical anion intermediates are synthetically powerful umpolung processes that enable electronically mismatched couplings between pairs of electron-rich or pairs of electron-poor organic fragments. Nevertheless, the adoption of these reactions as synthetic methods has been relatively slow in comparison with that of reactions involving more conventional reactive intermediates such as carbanions, carbocations, and neutral radicals. This Microreview provides a brief survey of radical ion chemistry and highlights the use of transition metal photocatalysis as a convenient means to investigate radical-ion-mediated transformations.
X-ray emission from PSR 0355+54

We have obtained a 20 ks observation of PSR 0355+54 using the ROSAT position sensitive proportional counter (PSPC). The pulsar is detected with a count rate of 4.2(+/- 1.3) x 10(exp -3)/s above the background. While the approximately 70 source counts are insufficient for spectral fitting, we have derived source parameters for specific cases of power law as well as blackbody spectra. For a Crab-like spectrum (photon index alpha = 2) we find L(sub x)(0.1-2.4 keV) = 1.0 x 10(exp 32) ergs/s, somewhat higher than upper limits reported from Einstein observations but consistent with typical L(sub x) versus E-dot values for other pulsars. For blackbody emission, we derive a temperature upper limit of approximately 9.5 x 10(exp 5) K for emission from the entire neutron star surface, which is consistent with standard models for cooling of the neutron star interior given a characteristic age 10(exp 5.75) yr. No evidence is present for modulation at the 156 ms pulsar period, setting a weak upper limit of approximately 75% for the pulsed fraction of the X-ray signal.
Race and Home Ownership: A Century-Long View

Abstract This paper uses census IPUMS data to analyze trends in racial differences in home ownership and housing values and to examine the connection between residential segregation and the housing status of blacks relative to whites. A widening in the ownership gap between 1940 and 1960 is explained largely by the increasing concentration of blacks in central city areas, whereas a narrowing in the ownership gap between 1960 and 1980 is explained only partly by changes in the relative characteristics of the black and white populations. Residential segregation did not widen the racial gap in home ownership rates in 1940 or 1980, but it did widen the gap in housing values after 1940.
THE INFRARED TELESCOPE FACILITY (IRTF) SPECTRAL LIBRARY: COOL STARS

We present a 0.8-5 μm spectral library of 210 cool stars observed at a resolving power of R ≡ λ/Δλ ~ 2000 with the medium-resolution infrared spectrograph, SpeX, at the 3.0 m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. The stars have well-established MK spectral classifications and are mostly restricted to near-solar metallicities. The sample not only contains the F, G, K, and M spectral types with luminosity classes between I and V, but also includes some AGB, carbon, and S stars. In contrast to some other spectral libraries, the continuum shape of the spectra is measured and preserved in the data reduction process. The spectra are absolutely flux calibrated using the Two Micron All Sky Survey photometry. Potential uses of the library include studying the physics of cool stars, classifying and studying embedded young clusters and optically obscured regions of the Galaxy, evolutionary population synthesis to study unresolved stellar populations in optically obscured regions of galaxies and synthetic photometry. The library is available in digital form from the IRTF Web site.
Optimizing a Functionally Graded Metal-Matrix Heat Sink Through Growth of a Constructal Tree of Convective Fins

This work focuses on an analytical approach to understand optimal material utilization in metal matrix heat exchangers. An objective of this work is to develop a bridge between a fully defined and discrete structure to that of a functionally graded porous media. A porous media heat exchanger is a structure which uses porous material, such as a metal foam, to achieve large convective surface areas in a small volume while also using the media as a conductive path from the heat source or sink. Therefore, a functionally graded porous media heat exchanger has a porosity that is specified as a function of position. Constructal theory is used here to develop increasingly complex convective fin structures, optimized at each level of complexity, which have a resulting characteristic of 2-D functional grading. The approach described here is developed from first principles by using Fourier’s law to develop analytical solutions and seeks to yield an optimized heat exchanger configuration that maximizes total heat transfer subject to a fixed amount conductive material, total volume, and flow condition.Copyright © 2013 by ASME
A Simple Procedure for the Preparation of 4-(α-Mercaptobenzyl)Phenoxyacetic Acid, A Thiol Linker Unit Used in Solid Phase Synthesis of Peptide-α-Thioacids

Abstract A convenient procedure for the preparation of the title compound via direct thionation of its alcohol precursor by Lawesson's reagent is described.
Novel fiber lasers and applications

Glass fiber lasers were invented in the 60's by Elias Snitzer at Americal Optical, soon after the invention of the first solid-state glass laser. However, it was not until the 80's when these waveguide devices were deployed in industrial applications, driven largely by the technological success of the semiconductor laser diode, which provided practical and efficient pumps, and by the advent of low loss rare-earth-doped optical fiber.
Why a scalar explanation of the L3 events is implausible

Abstract We investigate the question of whether an additional light neutral scalar can explain the l + l − γγ events with high invariant mass photon pairs recently observed by the L3 Collaboration. We parameterize the low energy effects of the unknown dynamics in terms of higher dimensional effective operators. We show that operators which allow for the scalar to be produced and decay into photon pairs will allow other observable processes that should have been seen in current experiments.
Microwave-Assisted Heterogeneous Cross-Coupling Reactions Catalyzed by Nickel-in-Charcoal (Ni/C)

A study involving the relatively rare combination of heterogeneous catalysis conducted under microwave conditions is presented. Carbon-carbon bond formation, including Negishi and Suzuki couplings, can be quickly effected with aryl chloride partners by using a base metal (nickel) adsorbed in the pores of activated charcoal. Aminations were also studied, along with cross-couplings of vinyl alanes with benzylic chlorides as a means to stereodefined allylated aromatics. Reaction times for all these processes are typically reduced from several hours to minutes in a microwave reactor.
Quantitative structure-property relationships for the prediction of vapor pressures of organic compounds from molecular structures

A quantitative structure−property relationship (QSPR) is developed to relate the molecular structures of 420 diverse organic compounds to their vapor pressures at 25 °C expressed as log(vp), where vp is in pascals. The log(vp) values range over 8 orders of magnitude from −1.34 to 6.68 log units. The compounds are encoded with topological, electronic, geometrical, and hybrid descriptors. Statistical and computational neural network (CNN) models are built using subsets of the descriptors chosen by simulated annealing and genetic algorithm feature selection routines. An 8-descriptor CNN model, which contains only topological descriptors, is presented which has a root-mean-square (rms) error of 0.37 log unit for a 65-member external prediction set. A 10-descriptor CNN model containing a larger selection of descriptor types gives an improved rms error of 0.33 log unit for the external prediction set.
Comprehensive DFT study of nitrous oxide decomposition over Fe-ZSM-5.

The reaction mechanism for nitrous oxide decomposition has been studied on hydrated and dehydrated mononuclear iron sites in Fe−ZSM-5 using density functional theory. In total, 46 different surface...
THE EDGE STATES OF THE BF SYSTEM AND THE LONDON EQUATIONS

It is known that the 3D Chern–Simons interaction describes the scaling limit of a quantum Hall system and predicts edge currents in a sample with boundary, the currents generating a chiral U(1) Kac-Moody algebra. It is no doubt also recognized that, in a somewhat similar way, the 4D BF interaction (with B a two-form, dB the dual *j of the electromagnetic current, and F the electromagnetic field form) describes the scaling limit of a superconductor. We show in this paper that there are edge excitations in this model as well for manifolds with boundaries. They are the modes of a scalar field with invariance under the group of diffeomorphisms (diffeos) of the bounding spatial two-manifold. Not all diffeos of this group seem implementable by operators in quantum theory, the implementable group being a subgroup of volume-preserving diffeos. The BF system in this manner can lead to the w1+∞ algebra and its variants. Lagrangians for fields on the bounding manifold which account for the edge observables on quantization are also presented. They are the analogs of the (1+1)-dimensional massless scalar field Lagrangian describing the edge modes of an Abelian Chern-Simons theory with a disk as the spatial manifold. We argue that the addition of “Maxwell” terms constructed from F∧*F and dB∧*dB does not affect the edge states, and that the augmented Lagrangian has an infinite number of conserved charges—the aforementioned scalar field modes—localized at the edges. This Lagrangian is known to describe London equations and a massive vector field. A (3+1)-dimensional generalization of the Hall effect involving vortices coupled to B is also proposed.
A TURBULENT INTERSTELLAR MEDIUM ORIGIN OF THE BINARY PERIOD DISTRIBUTION

We present a semiempirical model of isolated binary star formation. This model includes the effects of turbulence in the initial state of the gas and has binary orbital parameters consistent with observation. This model therefore provides a framework with which to examine the relative importance of turbulence in the context of isolated binary star formation and to make quantitative predictions to compare against observation. The primary results of this model are as follows: (1) a quantitative prediction of the initial width of the binary period distribution(� log Pd ¼ 1:6 2:1forastarformationefficiencyintherange � � ¼ 0:1 0:9),(2)arobustanticorrelation of binary period and mass ratio, (3) a robust, positive correlation of binary period and eccentricity, and (4) a robust prediction that the binary separation of low-mass systems should be less than that of solar-mass or larger systems. These predictions are in good agreement with observations of pre‐main-sequence binary systems with periods of P > 10 3 days, which account for the majority of all binaries. We conclude with a brief discussion of the implications of our results for observational and theoretical studies of multiple star formation. Subject headings: binaries: general — gravitation — hydrodynamics — stars: formation
NbN materials development for practical superconducting devices

Power switches such as a Superconducting Fault Current Limiter require large cross sectional area superconductors with both high critical current density J c and normal state resistivity ρ n . Large values of J c and ρ n have been previously reported in small cross sectional area "weak links" of NbN. We report on reactively sputtered NbN films up to 5 μm thick and 2.2 cm wide which have ρ n > 200 μΩ cm and a self-field J c up to 106A/cm2. Severe degradation in J c was observed with increasing film width and for millisecond current pulses. This degradation could be substantially reduced by stabilization with either low ρ n normal metal or the use of a sapphire substrate. The resistivity and critical current dependence both imply Josephson coupled grains and the results will be discussed within that model.
Synthesis and characterization of tetraalkylammonium salts of bis(5,6-dihydro-1,4-dithiin-2,3-dithiolato)cobaltate(III). Crystal structure of [(C4H9)4N]2[Co(DDDT)2]2

Abstract The reaction between CoCl2·6H2O and K2DDDT (the potassium salt of 1,2-dithiolene 5,6-dihydro-1,4- dithiin-2,3-dithiolate) under an argon atmosphere yields a dimeric dianion which can be isolated as a tetraalkylammonium salt. Constant potential electrolysis of the formally Co(III) product yields a Co(II) species. Both complexes are extremely sensitive to air in solution. The solid Co(III) product, however, is sufficiently air stable to allow a structural analysis of the tetrabutylammonium salt. The crystal belongs to the monoclinic space group C2/c with unit cell dimensions of a=23.626(3), b=16.915(3), c= 16.294(2) A, β=101.62(1)°, Z=8. The coordination around the cobalt atom is best described as square pyramid with an average basal CoS bond length of 2.197(1) A and an apical CoS distance of 2.328(1) A. The dimeric structure allows for S…S contacts in the crystal lattice as short as 3.22 A. The structure refined to R=0.037 and Rw=0.053. The frozen glass ESR spectrum of the Co(II) complex exhibits three sets of eight lines with g1=1.933, g2=2.067 and g3=2.860. A cyclic voltammogram contains a two-electron reversible wave, a quasi-reversible one- electron wave and a reversible one-electron wave indicating a four-member electrochemical series: [Co- (DDDT)2]2o[Co(DDDT)2]2− ⇄[Co(DDDT)2]22−⇄2Co(DDDT)22−. The solid-state 13C NMR spectrum shows different resonances for carbons in the double bonds of the ligand, consistent with splitting of the C=C stretch in the IR spectrum.
Minimal length elements in some double cosets of Coxeter groups

Abstract We study the minimal length elements in some double cosets of Coxeter groups and use them to study Lusztig's G-stable pieces and the generalization of G-stable pieces introduced by Lu and Yakimov. We also use them to study the minimal length elements in a conjugacy class of a finite Coxeter group and prove a conjecture in [M. Geck, S. Kim, G. Pfeiffer, Minimal length elements in twisted conjugacy classes of finite Coxeter groups, J. Algebra 229 (2) (2000) 570–600].
Pegylated filgrastim (PF) after high dose chemotherapy (HDC) and autologous stem cell transplant (ASCT)

6639 Background: PF (6 mg fixed dose) is equivalent to daily filgrastim (F) (5 mcg/kg/day for 14 days) after chemotherapy in decreasing the duration of neutropenia. Daily F (5 mcg/kg) started after HDC and ASCT leads to significant decrease in time to neutrophil engraftment (NE). The role of PF after HDC and ASCT is not known. We propose to study the role of PF given as a single fixed dose (6 mg) SQ on day +1 after stem cell (SC) infusion. Methods: Fifteen patients (pts.) undergoing HDC and ASCT using peripheral blood SC for multiple myeloma or lymphoma have been enrolled in an ongoing study. SC were collected with peripheral blood pheresis after cyclophosphamide (3 g/sq.m) and daily F (10 mcg/kg). All pts. were eligible for HDC and ASCT as per institutional criteria and consented. The conditioning regimens were high dose melphalan (200 mg/sq.m) for myeloma, and cyclophosphamide (7200 mg/sq.m), BCNU (400 mg/sq.m) and infusional etoposide (2400 mg/sq.m) for lymphoma. Pts. received antiinfective prophylaxis...
Active RC Synthesis for Significant Reduction in Magnitudes of Reactive Elements

Low impedance levels and/or large system time constants lead to network realizations with large total reactance values in ordinary passive and active RC synthesis. It is shown how active RC networks may, instead, be designed, in which one may freely a priori specify the total capacitance and the input and output resistances. The basic design philosophy is to assign relatively faroff poles to the passive part of the system. Feedback is used to obtain the desired close-in (large time constant) system poles. In one method, employing a single negative-impedance-converter, any number of system poles may be simultaneously realized. However, the output is very sensitive to variations in active and passive parameter values. Also, the negative-impedance-converter must act as such over the bandwidth of the passive part of the network, which part is much larger than that of the system as a whole. A second approach is far more practical. It employs a cascade of isolated canonic second-order structures, each of which realizes a pair of system poles. The resulting design is much less sensitive to active and passive parameter variations, and is much easier to tune. The structure used is especially suitable for narrow-band filtering. Also, the active element bandwidth need only be of the same order of magnitude as that of the system poles. Design relations are developed and optimized with respect to a figure of merit ASA, being the product of amplifier gain required and system sansitivity to amplifier gain variations.
Increasing Competition and the Winner¿s Curse: Evidence from Procurement

We assess empirically the effects of the winner's curse which, in common-value auctions, counsels more conservative bidding as the number of competitors increases. First, we construct an econometric model of an auction in which bidders' preferences have both common- and private-value components, and propose a new monotone quantile approach which facilitates estimation of this model. Second, we estimate the model using bids from procurement auctions held by the State of New Jersey. For a large subset of these auctions, we find that median procurement costs rise as competition intensifies. In this setting, then, asymmetric information overturns the common economic wisdom that more competition is always desirable.
Reactivity of molybdenum and tungsten disilene complexes

Abstract The reactions of the η2 -disilene complexes Cp2M(η 2-Me2SiSiMe2) (M = Mo, 1a; W, 1b) with a variety of inorganic and organic substrates are reported. Compound 1a reacts with methanol to yield Cp2Mo(SiMe 2H)(SiMe2OMe) (2,> 80%) and Cp2Mo(H)(Si Me2SiMe2OMe) (3,
Optimality and Improvement of Dynamic Voltage Scaling Algorithms for Multimedia Applications

The high complexity and time-varying workload of emerging multimedia applications poses a major challenge for dynamic voltage scaling (DVS) algorithms. Although many DVS algorithms have been proposed for real-time applications, an efficient method for evaluating the optimality of such DVS algorithms for multimedia applications does not yet exist. In this paper, we propose the first offline linear programming (LP) method to determine the minimum energy consumption for processing multimedia tasks under stringent delay deadlines. On the basis of the obtained energy lower bound, we evaluate the optimality of various existing DVS algorithms. Furthermore, we extend the LP formulation in order to construct an online DVS algorithm for real-time multimedia processing based on robust sequential linear programming. Simulation results obtained by decoding a wide range of video sequences show that, on average, our online algorithm provides a scheduling solution that requires less than 0.3% more energy than the optimal lower bound with only 0.03% miss rate. In comparison, a very recent algorithm consumes approximately 4% more energy than the optimal lower bound at the same miss rate.
A test complex for Gorensteinness

Let R be a commutative noetherian ring with a dualizing complex. By recent work of Iyengar and Krause (2006), the difference between the category of acyclic complexes and its subcategory of totally acyclic complexes measures how far R is from being Gorenstein. In particular, R is Gorenstein if and only if every acyclic complex is totally acyclic. In this note we exhibit a specific acyclic complex with the property that it is totally acyclic if and only if R is Gorenstein.
The challenge of empirically assessing the effects of constitutions

Mutually supporting methodologies are necessary for building a convincing case establishing a particular effect. Strengths and weaknesses of four empirical methods are discussed. Econometric methods quantify the relative importance of different factors and may assess the time frame over which constitutions matter, but have difficulties in dealing with nonlinear interactions among constitutional and cultural details. Cluster analysis can be a pre-requisite to other methods, and an analytic method in itself, useful for identifying the details that really matter and discovering surprising patterns in the data. I discuss the application of cluster analysis on the Comparative Constitutions Project database. Qualitative comparative analysis can reveal the hidden structure of interactions among different variables, but robustness checks are difficult to perform. Case studies are useful for distinguishing between rules-in-use and rules-in-form and for discovering important informal aspects. They can deal with com...
A Review of Porous Manganese Oxide Materials

This review concerns the synthesis, characterization, and applications of porous manganese oxides during the last two years. The synthesis of porous tunnel structures, layered structures, and related materials is discussed. Both microporous and mesoporous systems materials are covered here. Characterization discussed here focuses around structural studies. The focus of the application sections include electrochemical and catalytic studies.
Ten-dimensional heterotic string as a soliton

Abstract It is shown that the heterotic string emerges as a soliton in the type I superstring theory in ten dimensions. The collective coordinates of the soliton are described by a smooth, chiral worldsheet theory. There are eight bosonic and eight right-moving fermionic zero modes that arise from the partially broken supertranslations. In addition, there are 496 charged bosonic zero modes of the gauge field that describe a left-moving WZNW model on a spin(32) Z 2 group manifold. Small, stable loops of the solitonic string furnish the massive states required by duality that transform as spinors of spin(32).
Expression and Function of the c-kit Proto-Oncogene Protein in Mouse Sperm

The presence and role of the c-kit protein were examined in mature sperm of the mouse. Monoclonal antibodies (mAbs) against the c-kit protein were used to perform immunohistochemical staining, electron microscopy studies, and Western blot analysis. The acrosomal region of both fixed and unfixed noncapacitated sperm stained with the antibodies. No acrosomal staining was noted in acrosome-reacted (AR) sperm. Electron microscopy studies demonstrated immunogold label on the plasma membrane of the acrosome and confirmed the lack of binding following the acrosome reaction. Proteins corresponding to 33 kDa, 48 kDa, and 150 kDa were detected by the antibodies utilizing Western blot analysis. The 48-kDa and 150-kDa proteins were released into the media during sperm capacitation, and release from the acrosome was dependent upon the acrosome reaction. The mAbs significantly inhibited the acrosome reaction and increased sperm agglutination. Monoclonal antibody ACK1 significantly inhibited the motility of the sperm, whereas mAbs ACK2 and NCL-ckit did not. These results suggest that c-kit-related proteins are present in mature sperm and may play a role in capacitation and/or the acrosome reaction.
Clifford correspondence for algebras

Abstract We give a Clifford correspondence for an algebra A over an algebraically closed field, that is an algorithm for constructing some finite-dimensional simple A -modules from simple modules for a subalgebra and endomorphism algebras. This applies to all finite-dimensional simple A -modules in the case that A is finite-dimensional and semisimple with a given semisimple subalgebra. We discuss connections between our work and earlier results, with a view towards applications particularly to finite-dimensional semisimple Hopf algebras.
Processes controlling fast fracture of brittle solids

Brittle fracture in solids has attracted the attention of engineers and physicists because of both its technological interest and inherent scientific curiosity. Bridging the different approaches requires extensive experimental investigations and multiscale computational schemes. The authors discuss the microscale processes that control the development of fast fracture in brittle materials.
Is a Group of Economists Better Than One? Than None?

Can economists forecast the direction of economic growth? Casual observation indicates that individual economists make poor predictions of economic growth and that their forecasts are highly correlated. This article discusses the loss of information resulting from correlation and develops a method of combining forecasts that are cross-sectionally correlated. This approach greatly increases the accuracy of near-term forecasts of the direction of economic growth, although the individual with the best historical performance is better over longer horizons. Overall, when the data are properly aggregated, economists predict the direction of near-term economic growth and call turning points reasonably well. Copyright 1996 by University of Chicago Press.
Trajectory based validation of the Shuttle heating environment

Chemically reacting,three-dimensional,fullNavier ‐Stokescalculationsaregenerated around theshuttleorbiter and are compared with the STS-2 e ight database at eight trajectory locations. Numerical estimates of quantities necessary for thermal protection system design, surface temperature and heating proe les, integrated heat load, bond-line temperatures, and thermal protection system thicknesses arecompared with theSTS-2 shuttledata. The effects of surface kinetics, turbulence, and grid resolution are investigated. It is concluded that trajectory-based thermal protection system sizing, the use of a Navier ‐Stokes e ow solver combined with a conduction analysis applied over an entry trajectory, is a benee cial tool for future thermal protection system design. This conclusion is based on a reasonable agreement between the e ight data and numerical predictions of surface heat transfer and temperature proe les, integrated heat loads and bond-line temperatures at most of the wind-side thermocouples. Theeffectsofturbulentheating on thermalprotection system designareillustrated.Forfuturelargeentry vehicles, it is concluded that the prediction of turbulent transition will be a major driver in the thermal protection system design process. Finally,onepotential payoff ofusingtrajectory-based thermalprotection system sizing,a reduction in thermal protection system mass, is illustrated. Nomenclature CT = heat transfer coefe cient, W/m 2 -K cp = heat capacity of solid cs
Gender-specific gene-environment interaction in alcohol dependence: the impact of daily life events and GABRA2.

Gender-moderated gene–environment interactions are rarely explored, raising concerns about inaccurate specification of etiological models and inferential errors. The current study examined the influence of gender, negative and positive daily life events, and GABRA2 genotype (SNP rs279871) on alcohol dependence, testing two- and three-way interactions between these variables using multi-level regression models fit to data from 2,281 White participants in the Collaborative Study on the Genetics of Alcoholism. Significant direct effects of variables of interest were identified, as well as gender-specific moderation of genetic risk on this SNP by social experiences. Higher levels of positive life events were protective for men with the high-risk genotype, but not among men with the low-risk genotype or women, regardless of genotype. Our findings support the disinhibition theory of alcohol dependence, suggesting that gender differences in social norms, constraints and opportunities, and behavioral undercontrol may explain men and women’s distinct patterns of association.
One-sided patience with one-sided communication does not justify stackelberg equilibrium☆

Abstract The theory of games (with complete information) in which a single patient longrun player faces a succession of short-run opponents cannot plausibly be used to justify the Stackelberg solution concept, because if that player can select which subgame-perfect equilibrium is to be played then she can presumably also change her selection. Consequently, while she can choose among one-shot Nash outcomes, she cannot achieve the Stackelberg outcome.
Structural Changes and Strategies in the North American Flour Milling Industry

Dynamic structural changes in the flour milling industry have resulted in fewer and larger firms, larger plants, and increased concentration. A number of features in the North American Free Trade Agreement (NAFTA) could have an impact on strategies and competition in this industry. This article has three objectives. First, structural characteristics of the flour milling industries in each country, policies, and other competitive factors are described. Second, important fundamental changes from the US/Canada Free Trade Agreement (CUSTA) and NAFTA are described. Apparent changes in firm strategies since these agreements are highlighted and analyzed. © 1995 John Wiley & Sons, Inc.
Synthesis of (+)-1,5-dideoxy-1,5-imino-d-galactitol, a potent α-d-galactosidase inhibitor

The key steps in the synthesis of the title compound (VIII) are cleavage of the 6-bromopyranoside (I) by dehydrobromination and reductive amination and subsequent mercuration with simultaneous ring closure.
The facile synthesis of diiodoalkenes by the addition of I2 to alkynes on alumina.

Abstract Iodine adds to a variety of alkynes on alumina at or slightly above room temperature to form diiodoalkenes.
Uniformly factoring weakly compact operators

Abstract Let X and Y be separable Banach spaces. Suppose Y either has a shrinking basis or Y is isomorphic to C ( 2 N ) and A is a subset of weakly compact operators from X to Y which is analytic in the strong operator topology. We prove that there is a reflexive space with a basis Z such that every T ∈ A factors through Z . Likewise, we prove that if A ⊂ L ( X , C ( 2 N ) ) is a set of operators whose adjoints have separable range and is analytic in the strong operator topology then there is a Banach space Z with separable dual such that every T ∈ A factors through Z . Finally we prove a uniform version of this result in which we allow the domain and range spaces to vary.
DRM: doesn't really mean digital copyright management

Copyright is a legal system embedded in a larger technological system. In order to examine the functions of copyright it is critical to examine the larger technological context of copyright: analog media and printed paper in particular. The copyright system includes both the explicit mechanisms implemented by law and the implicit mechanisms resulting from the technologically determinant features of paper and print. In order to prevent confusion between the legal, technical, and economic elements I refer to the whole as "copy accurate".Digital rights management design should explicitly address legal issue in copyright and economics of paper, technology of mass produced analog media, and print culture. An examination of that entire system (copy accurate) yields a return to first principles for the design of digital rights management systems.
Nucleophilic perfluoroalkylation of nitrones

Abstract New methods for perfluoroalkylation of carbon nitrogen double bonds have been developed. Addition of (trifluoromethyl)trimethylsilane (TMSCF 3 ) to α,N-diarylnitrones produced a series of α-(trifluoromethyl)-N-hydroxyl amines protected as their O-trimethylsilyl derivatives. An alternate procedure using pentafluoroethyllithium (F 5 C 2 Li) and chlorotrimethylsilane (TMSCl) afforded O-trimethylsilyl-α-(pentafluoroethyl)-N-hydroxyl amines.
How edge-reinforced random walk arises naturally

We give a characterization of a modified edge-reinforced random walk in terms of certain partially exchangeable sequences. In particular, we obtain a characterization of an edge-reinforced random walk (introduced by Coppersmith and Diaconis) on a 2-edge-connected graph. Modifying the notion of partial exchangeability introduced by Diaconis and Freedman in [3], we characterize unique mixtures of reversible Markov chains under a recurrence assumption.
Energy positivity, non-renormalization, and holomorphy in Lorentz-violating supersymmetric theories

This paper shows that the positive-energy and non-renormalization theorems of traditional supersymmetry survive the addition of Lorentz violating interactions. The Lorentz-violating coupling constants in theories using the construction of Berger and Kostelecky must obey certain constraints in order to preserve the positive energy theorem. Seiberg’s holomorphic arguments are used to prove that the superpotential remains non-renormalized (perturbatively) in the presence of Lorentz-violating interactions of the Berger-Kostelecky type. We briefly comment on Lorentz-violating theories of the type constructed by Nibbelink and Pospelov to note that holomorphy arguments offer elegant proofs of many non-renormalization results, some known by other arguments, some new.
Synergistic–cooperative combination of enamine catalysis with transition metal catalysis

Synergistic–cooperative combination of enamine catalysis with transition metal catalysis is an emerging and exciting field aiming to achieve organic transformations that cannot be accomplished by individual catalysis. The biggest obstacle in this field lies in the catalyst incompatibility arising from Lewis acid–Lewis base interactions. Several strategies including soft/hard combination of a Lewis acid and a Lewis base, the utilization of a chelating ligand, and mixing an ammonium salt with a Lewis acid have been developed to solve the incompatibility problem. A number of new reactions and new reaction modes have been discovered using these strategies. In this review article, we aim to highlight these new discoveries found in the literature.
On yield consideration for the design of redundant programmable logic arrays

Redundancy techniques have been applied to conventional programmable logic arrays (PLAs) to allow for the repair of defective chips. When the redundancy technique is implemented in a VLSI or WSI chip design, the increased cost is proportional to the increased chip silicon area, and the additional spare lines can increase the silicon area and propagation delay. However, if the provided redundancy can be efficiently utilized to repair defective chip; then the additional spare lines may increase rather than decrease the chip yields. The possibility of yield enhancement through redundant design is analyzed, showing that the chip yield is increased significantly. >
Some comments on models of hadronic interactions at air shower energies

Several models of minimum-bias hadronic interactions at ultra-high energy that have been used for calculations of air showers share essential common features. In this talk I review these common elements and discuss some consequences. I concentrate on properties of hadron-nucleus interactions, and I use mean depth of shower maximum as a function of primary energy to illustrate my main points. I will contrast these models with models that use a more naive treatment of hadronic interactions in nuclei but which have been successfully used to interpret measurements of depth of shower maximum.
GPS performance: what is normal?

Proposed solutions to the GPS integrity issue generally focus on means of reliably determining when GPS deviates from some standard of performance acceptable to a given user group, and warning that group not to use the service. One of the key elements in the development of any reliable GPS integrity response system is an understanding of how GPS normally performs. To support that need, this paper examines the performance of the current Block II satellite constellation from a time-ordered and a statistical behavior perspective. The paper begins with a general discussion that relates GPS accuracy characteristics to the integrity problem. The time-ordered behavior of GPS position solution errors is then described, and error behavior dependencies on user location are defined. The paper then develops GPS range and position error statistical distribution characteristics. Finally, the results of the time-ordered and statistical behavior analyses are assessed in terms of their implications for the GPS integrity monitoring and response problem.