cssi/SciSciGPT-SciSciNet huggingface dataset:
On the Radio/X-ray Correlation in Microquasars

Context. The broadband spectral energy distribution of microquasars has proven to be a valuable tool for assessing the roles of je ts and accretion flows in microquasars, as well as the coupling b etween the two. The coupling might manifest itself observationally in the correlated radio and X-ray variabilities of a source. Su ch a radio/X-ray correlation has indeed been seen in several microquasars during the low-hard state and subsequently been claimed to be universal for all. If proven, the universal correlation wo uld have profound implications on theoretical models. However, there is already observational evidence that suggests otherwi se. Aims. In this paper, we critically examine the radio/X-ray correlation in a sample of microquasars, in the low-hard state as well as during state transitions, with a goal of testing the claimed universality of the correlation on observational grounds. Methods. We have assembled a comprehensive data set from the simultaneous/contemporaneous radio and X-ray observations of representative microquasars. The data have allowed us to quantify the radio/X-ray correlation on a source by source basis. Results. We find that the radio /X-ray correlation of microquasars exhibits diverse behaviors, both in the low-hard and transitional states, ranging from being very week (or none at all) to very strong. There is even a hint of spectral dependence of the correlation in some cases. Conclusions. Our results rule out the claimed universality of the radio/X-ray correlation of microquasars, even for the low-hard state. On the other hand, we do find that the radio and X-ray variabili ties are, to varying degrees, correlated in most cases.
The Velocity Dispersion Profile of the Remote Dwarf Spheroidal Galaxy Leo I: A Tidal Hit and Run?

We present new kinematic results for 387 stars near the Milky Way satellite dwarf spheroidal galaxy Leo I. Spectra were obtained with the Hectochelle multiobject echelle spectrograph on the MMT, centered in the optical near 5200 A. From 297 repeat measurements of 108 stars, we estimate the mean velocity error (1 σ) of our sample to be 2.4 km s−1, with a systematic precision of ≤1 km s−1. The final sample of 328 Leo I members gives a mean heliocentric velocity of -->282.9 ± 0.5 km s−1 and a dispersion of -->9.2 ± 0.4 km s−1. The dispersion profile of Leo I is flat to beyond its classical tidal radius. We fit the profile to various equilibrium dynamical models. We strongly rule out all models where mass follows light. Anisotropic Sersic+NFW models fit the dispersion profile well, but isotropic models are ruled out at a 95% confidence level. Inside a projected radius of ~1040 pc, the mass and V-band mass-to-light ratio of Leo I from equilibrium models are in the ranges -->(5–7) × 107 M☉ and 9-14 (solar units), respectively. Leo I members outside a break radius of -->Rb ~ 400'' (500 pc) exhibit significant velocity anisotropy, whereas stars interior to this radius are consistent with an isotropic velocity distribution. We interpret the break radius as the tidal radius of Leo I at perigalacticon some 1-2 Gyr ago. This interpretation accounts for the complex star formation history of Leo I, population segregation within the galaxy, and Leo I's large outward galactocentric velocity. The lack of evident tidal arms in Leo I suggests that the galaxy may have been injected into its present highly elliptical orbit by a third body a few Gyr before its last perigalacticon. This scenario is plausible within current hierarchical structure formation models.
A multi—objective personal computer model for energy conservation planning

Abstract In this paper a microcomputer software package is implemented to help the decision maker (DM) to obtain the best energy conservation policy in the melting phase of glass production. A multiple objective linear programming formulation for the melting phase is developed that demonstrates how different energy conservation options can be incorporated into the model. An interactive paired comparison method as a decision support system is discussed. The paired comparison method is implemented by the DM to find the best compromise solution given the conflicting objectives. A report of the implementation and the DM's interactions with the method is provided.
Solvent effects on photophysical parameters for coumarin laser dyes

Abstract The red shifts of absorption bands of coumarin dyes in polar solvents correlate with the solvent polarity-polarizability parameter π ∗ . Emission frequencies correlate well with the hydrogenbonding parameter, α and show a regular dependence on π ∗ if a solvent polarizability correction term is incorporated for chlorinated hydrocarbon and aromatic solvents. Quantum yield and lifetime measurements reveal that the reduced emission observed for dyes with non-rigid structures is associated with enhanced nonradiative decay in polar solvents. The solvent effect on fluorescence yield is interpreted in terms of the intervention of planar and non-planar excited species which appears to be general for polar dyes.
Single-mode coherent synchrotron radiation instability

The microwave instability driven by the coherent synchrotron radiation (CSR) has been previously studied [S. Heifets and G. V. Stupakov, Phys. Rev. ST Accel. Beams 5, 054402 (2002)] neglecting effect of the shielding caused by the finite beam pipe aperture. In practice, the unstable mode can be close to the shielding threshold where the spectrum of the radiation in a toroidal beam pipe is discrete. In this paper, the CSR instability is studied in the case when it is driven by a single synchronous mode. A system of equations for the beam-wave interaction is derived and its similarity to the 1D free-electron laser theory is demonstrated. In the linear regime, the growth rate of the instability is obtained and a transition to the case of continuous spectrum is discussed. The nonlinear evolution of the single-mode instability, both with and without synchrotron damping and quantum diffusion, is also studied.
The Information Technology Revolution and the Puzzling Trends in Tobin's average q

A growing literature argues that the Information Technology revolution caused the stock market crash of 1973-1974, its subsequent stagnation and eventual recovery. This paper employs general equilibrium theory to test whether this good news hypothesis is consistent with the behavior of US equity prices and with the trends in corporate output, investment and consumption. I …nd it is not. A model based exclusively on good news can make equity prices fall as much as in the data but it must also imply a strong economic expansion right when the US economy stagnated. However, when the observed productivity slowdown in old production methods is incorporated into the model consistency with major macroeconomic aggregates can be achieved and a 20% drop in equity values can be accounted for. (JEL E44, O33, O41)
Development of braided rope seals for hypersonic engine applications - Flow modeling

A new type of engine seal is being developed to meet the needs of advanced hypersonic engines. A seal braided of emerging high temperature ceramic fibers comprised of a sheath-core construction was selected for study based on its low leakage rates. Flexible, low-leakage, high temperature seals are required to seal the movable engine panels of advanced ramjet-scramjet engines either preventing potentially dangerous leakage into backside engine cavities or limiting the purge coolant flow rates through the seals. To predict the leakage through these flexible, porous seal structures new analytical flow models are required. Two such models based on the Kozeny-Carman equations are developed herein and are compared to experimental leakage measurements for simulated pressure and seal gap conditions. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal. The first model treats the seal as a homogeneous fiber bed. The second model divides the seal into two homogeneous fiber beds identified as the core and the sheath of the seal. Flow resistances of each of the main seal elements are combined to determine the total flow resistance. Comparisons between measured leakage rates and model predictions for seal structures covering a wide range of braid architectures show good agreement. Within the experimental range, the second model provides a prediction within 6 to 13 percent of the flow for many of the cases examined. Areas where future model refinements are required are identified.
BROMINATION OF ALKYNES WITH SODIUM PERBORATE AND SODIUM BROMIDE

Abstract Bromination of alkynes using sodium bromide in the presence of sodium perborate provides a convenient and safe method for generating vicinal dibromoalkenes.
The Value of Homes in Cluster Development Residential Districts: The Relative Significance of the Permanent Open Spaces Associated with Clusters

This study uses the hedonic framework to look at an aspect of planning and its effects on property values. Specifically, the study examines the impacts of cluster residential development on home value using data on Lower Gwynedd Township (Pennsylvania, USA). Other factors remaining constant, the study finds that properties located within cluster developments (CLUS) attract premium prices of roughly 3.9 %, on average, relative to properties in conventional developments. However, part of the 3.9 % price premium is attributable to the permanent open spaces which are parts and parcels of clusters. When the variable for open space (OPEN) is introduced, the cluster (CLUS) premium reduces to 2.02 % suggesting the relative importance the permanent open spaces. The open space variable (OPEN) is associated with a premium of as much as 5.2 %, on average. The density of development variable (DENSITY) is significantly negative at conventional levels. The normative implication of the density finding is that raising permitted densities, per se, in a sub-urban setting where market densities are lower than permitted densities, will have adverse impacts on home value. The results of this study provide empirical support for sustainable, greener, residential cluster development.
Intramolecular [2 + 2] cycloaddition reactions of alkynyl ether derived ketenes. A convenient synthesis of donor-acceptor cyclobutanes.

Mild thermolysis of tert-butyl alkynyl ethers furnishes aldoketenes, which undergo facile [2+2] cycloaddition reactions with pendant di- and trisubstituted alkenes. A wide variety of cis-fused cyclobutanones are produced in moderate to high diastereoselectivity and good to excellent yields by this method, and free hydroxyl groups are tolerated in the ene-ynol ether starting materials. Enol-ynol ethers also undergo efficient reaction to produce donor-acceptor cyclobutanes in high yields.
Loop calculations in quantum-mechanical non-linear sigma models

Abstract By carefully analyzing the relations between operator methods and the discretized and continuum path integral formulations of quantum-mechanical systems, we have found the correct Feynman rules for one-dimensional path integrals in curved spacetime. Although the prescription how to deal with the products of distributions that appear in the computation of Feynman diagrams in configuration space is surprising, this prescription follows unambiguously from the discretized path integral. We check our results by an explicit two-loop calculation.
Stellar Populations of Elliptical Galaxies in the Local Universe

We study the stellar populations of 1923 elliptical galaxies at z < 0.05 selected from the Sloan Digital Sky Survey as a function of velocity dispersion, σ, and environment. Our sample constitutes among the largest high-fidelity samples of elliptical galaxies with uniform imaging and optical spectroscopy assembled to date. Confirming previous studies, we find that elliptical galaxies dominate at high luminosities (L*), and that the highest-σ ellipticals favor high-density environments. We construct average, high signal-to-noise spectra in bins of σ and environment and find the following: (1) lower-σ galaxies have a bluer optical continuum and stronger (but still weak) emission lines; (2) at fixed σ, field ellipticals have a slightly bluer stellar continuum, especially at wavelengths 4000 A, and have stronger (but still weak) emission lines compared with their group counterparts, although this environmental dependence is strongest for low-σ ellipticals and the highest-σ ellipticals are much less affected. Based on Lick indices measured from both the individual and average spectra, we find that (1) at a given σ, elliptical galaxies in groups have systematically weaker Balmer absorption than their field counterparts, although this environmental dependence is most pronounced at low σ; (2) there is no clear environmental dependence of Fe, while the α-element absorption indices such as Mg b are only slightly stronger in galaxies belonging to rich groups. An analysis based on simple stellar populations (SSPs) reveals that more massive elliptical galaxies are older, more metal-rich, and more strongly α-enhanced. We also find that (1) the SSP-equivalent ages of galaxies in rich groups are, on average, ~1 Gyr older than in the field, although once again this effect is strongest at low σ; (2) galaxies in rich groups have slightly lower [Fe/H] and are marginally more strongly α-enhanced; and (3) there is no significant environmental dependence of total metallicity, [Z/H]. Our results are generally consistent with stronger low-level recent star formation in field ellipticals at low σ, similar to recent results based on ultraviolet and infrared observations. We conclude with a brief discussion of our results in the context of recent theoretical models of elliptical galaxy formation.
A new method for the generation of substituted homotrimethylenemethane diradicals

Abstract The elimination of nitrogen from the 1,1-diazine 11 produces the homotrimethylenemethane diradical 12 which undergoes ring closure to form the substituted methylenecyclobutanes 13 and 14 . No cleavage of the diradical intermediate to produce 1,1-dimethylallene and styrene is observed.
OPTICAL AND X-RAY SPECTROSCOPY OF 1E 0449.4(1823: DEMISE OF THE ORIGINAL TYPE 2 QSO

New optical spectra of the original narrow-line quasar 1E 0449.4-1823 show that it now has broad emission lines of considerable strength, eliminating it as a type 2 QSO candidate. Although broad emission line components were probably weakly present in 1981 and 1984, they have certainly increased in strength and are accompanied by Balmer continuum emission that makes the spectrum bluer than it was previously. We suggest that the behavior of 1E 0449.4-1823 is the same as that of some Seyfert 1.8 and 1.9 galaxies, in which Goodrich attributed long-term variations of their broad Balmer lines to dynamical motions of obscuring material located in or around the broad-line region. The optical continuum and broad emission line regions of 1E 0449.4-1823 may still be partly covered in our line of sight, which would explain its large forbidden-line equivalent widths and flat αox relative to other low-redshift QSOs. Also present are apparent absorption features in the broad Balmer lines and in Mg II, which may be related to the past obscuration and current emergence of the broad-line region. However, it is difficult to distinguish absorption from broad emission line peaks that are displaced in velocity; we consider the latter a plausible competing interpretation of these peculiar line profiles. An ASCA X-ray spectrum of 1E 0449.4-1823 can be fitted with a power law of Γ=1.63 -->+ 0.12−0.09, intrinsic NH < 9 × 1020 cm-2, and no Fe Kα line emission. Its 2-10 keV luminosity is 6.7 × 1044 ergs s-1. Thus, there is no evidence for Seyfert 2 properties in the X-ray emission from 1E 0449.4-1823, which resembles that of an ordinary QSO. With regard to the still hypothetical type 2 QSOs, we argue that there is little evidence for the existence of any among X-ray-selected samples.
Max weight learning algorithms with application to scheduling in unknown environments

We consider a discrete time stochastic queueing system where a controller makes a 2-stage decision every slot. The decision at the first stage reveals a hidden source of randomness with a control-dependent (but unknown) probability distribution. The decision at the second stage incurs a penalty vector that depends on this revealed randomness. The goal is to stabilize all queues and minimize a convex function of the time average penalty vector subject to an additional set of time average penalty constraints. This setting fits a wide class of stochastic optimization problems. This includes problems of opportunistic scheduling in wireless networks, where a 2-stage decision about channel measurement and packet transmission must be made every slot without knowledge of the underlying transmission success probabilities. We develop a simple max-weight algorithm that learns efficient behavior by averaging functionals of previous outcomes. The algorithm yields performance that can be pushed arbitrarily close to optimal, with a tradeoff in convergence time and delay.
Iodoetherification of unactivated alkenes catalyzed by diphosphine palladium(II) complexes

A palladium-catalyzed intramolecular iodoetherification of alkenes is reported. The reaction is efficient and highly diastereoselective for disubstituted alkenes. The tether length between the alcohol and alkene can be varied to produce tetrahydrofuran and tetrahydropyran rings. Diphosphine palladium(II) salts are highly active catalysts enabling future studies on the development of an enantioselective process.
A Disruptive Innovation Model for Indigenous Medicine Research: A Nigerian Perspective

Non-availability of affordable medicines remains a recurring theme in the healthcare sector of countries in the South where it hampers drug compliance and creates an ambience for continued morbidity and mortality. Countries in sub-Saharan Africa have attempted to remedy this situation via developing drugs from indigenous pharmacopeia; however, their efforts have yielded only a collection of one-off success stories due to a prevailing climate of economic, infrastructural and technological constraints. Using Nigeria as a case example, this paper argues that the core issues plaguing pharmaceutical innovation in developing countries go beyond existing constraints but revolve around an inability to evolve viable frameworks vis-a-vis scientific validation as well as failure on the part of researchers (in the course of conducting their research) and policy makers (in formulating and implementing drug-related policies) to reckon with the local reality. On this note, this paper explores a disruptive innovational f...
Nucleophilic Substitution Reactions of 2-Phenylthio-Substituted Carbohydrate Acetals and Related Systems: Episulfonium Ions vs. Oxocarbenium Ions as Reactive Intermediates

A powerful approach for controlling the stereochemistry of glycosylation reactions involves using a directing group at an adjacent carbon to influence the stereochemistry of nucleophilic attack. The use of substituents such as I, PhS, and PhSe has proven to be especially valuable because it enables the preparation of 2-deoxysugars after reductive removal of the directing group. The mechanisms of these reactions are generally considered to involve nucleophilic opening of bridged onium ions and to proceed with inversion. Onium ions, however, equilibrate with open cations, and these open forms can be favored when the cation is highly stabilized. Although the selectivities of reactions of carbohydrate-derived cations are consistent with the intermediacy of onium ions, the reactions of acyclic cations are not. Instead, consideration of the preferred conformations of the oxocarbenium ions and stereoelectronically favored additions to these intermediates provides a predictive model to explain the diastereoselectivities observed in reactions of oxocarbenium ions bearing proximal heteroatoms.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Meritocracy Voting: Measuring the Unmeasurable

Learned societies commonly carry out selection processes to add new fellows to an existing fellowship. Criteria vary across societies but are typically based on subjective judgments concerning the merit of individuals who are nominated for fellowships. These subjective assessments may be made by existing fellows as they vote in elections to determine the new fellows or they may be decided by a selection committee of fellows and officers of the society who determine merit after reviewing nominations and written assessments. Human judgment inevitably plays a central role in these determinations and, notwithstanding its limitations, is usually regarded as being a necessary ingredient in making an overall assessment of qualifications for fellowship. The present article suggests a mechanism by which these merit assessments may be complemented with a quantitative rule that incorporates both subjective and objective elements. The goal of “measuring merit” may be elusive, but quantitative assessment rules can hel...
SketchPadN-D: WYDIWYG Sculpting and Editing in High-Dimensional Space

High-dimensional data visualization has been attracting much attention. To fully test related software and algorithms, researchers require a diverse pool of data with known and desired features. Test data do not always provide this, or only partially. Here we propose the paradigm WYDIWYGS (What You Draw Is What You Get). Its embodiment, SketchPadND, is a tool that allows users to generate high-dimensional data in the same interface they also use for visualization. This provides for an immersive and direct data generation activity, and furthermore it also enables users to interactively edit and clean existing high-dimensional data from possible artifacts. SketchPadND offers two visualization paradigms, one based on parallel coordinates and the other based on a relatively new framework using an N-D polygon to navigate in high-dimensional space. The first interface allows users to draw arbitrary profiles of probability density functions along each dimension axis and sketch shapes for data density and connections between adjacent dimensions. The second interface embraces the idea of sculpting. Users can carve data at arbitrary orientations and refine them wherever necessary. This guarantees that the data generated is truly high-dimensional. We demonstrate our tool's usefulness in real data visualization scenarios.
An experimental study of turbulent boundary layer with slit suction

Abstract Experiments are performed on a flat plate with a transverse suction slit in the Reynolds number range 5 × 10 5 R e 6 . Mean velocity profiles, RMS values are measured with hot wire anemometry. Friction velocity is numerically calculated. The experiments showed that a classical boundary layer parameter α is related to the suction coefficient S c with an equation of the form: 1 n α with suction α without suction = A · S c + B for 0 and y ∗ > 10 . The value of A seems to depend strongly on the relative location with respect to suction slit and possibly weakly on Reynolds number.
Cell selection from technology libraries for minimizing power

Abstract In this paper, we present a new library-oriented cell selection approach to minimize power consumption of combinational circuits. We formulate the low power cell selection problem as a mixed integer-linear-programming (MILP) problem. Cells with different sizes, supply voltages, and threshold voltages, can be selected simultaneously by our unified approach. Level shifter insertion required by supply voltage scaling is integrated into the cell selection process and the effect of insertion positions on power consumption is investigated. We put special efforts to reduce the size of the MILP and present efficient and effective heuristics to solve the MILP in short CPU time. Experiments are conducted on ISCAS’85 benchmark circuits. A 0.5 μ CMOS library from IBM is used as the technology library. Comparing with other approaches which select cells with one or two kinds of variations, our approach achieve 9–26% more power saving in 30–79% less CPU time.
Simulation of sloshing dynamics induced forces and torques actuated on Dewar container driven by gravity gradient and jitter accelerations in microgravity

Some experimental spacecraft use superconducting sensors for gyro read-out and so must be maintained at a very low temperature. The boil-off from the cryogenic liquid used to cool the sensors can also be used, as the Gravity Probe B (GP-B) spacecraft does, as propellant to maintain attitude control and drag-free operation of the spacecraft. The cryogenic liquid for such spacecraft is, however, susceptible to both slosh-like motion and non-axisymmetric configurations under the influence of various kinds of gravity jitter and gravity gradient accelerations. Hence, it is important to quantify the magnitude of the liquid-induced perturbations on the spacecraft. We use the example of the GP-B to investigate such perturbations by numerical simulations. For this spacecraft disturbances can be imposed on the liquid by atmospheric drag, spacecraft attitude control maneuvers, and the earth's gravity gradient. More generally, onboard machinery vibrations and crew motion can also create disturbances. Recent studies suggest that high frequency disturbances are relatively unimportant in causing liquid motions in comparison to low frequency ones. The results presented here confirm this conclusion. After an initial calibration period, the GP-B spacecraft rotates in orbit at 0.1 rpm about the tank symmetry axis. For this rotation rate, the equilibrium liquid free surface shape is a 'doughnut' configuration for all residual gravity levels of 10(exp -6) g(sub 0) or less, as shown by experiments and by numerical simulations; furthermore, the superfluid behavior of the 1.8 K liquid helium used in GP-B eliminates temperature gradients and therefore such effects as Marangoni convection do not have to be considered. Classical fluid dynamics theory is used as the basis of the numerical simulations here, since Mason's experiments show that the theory is applicable for cryogenic liquid helium in large containers. To study liquid responses to various disturbances, we investigate and simulate three levels of gravity jitter (10(exp -6), 10(exp -7), and 10(exp -8) g(sub 0)) each at three predominant frequencies (0.1, 1.0, and 10 Hz), combined with a gravity gradient appropriate for the GP-B orbit. Dynamical evolution of sloshing dynamics excited fluid forces and torque fluctuations exerted on the dewar container driven by the combined gravity gradient and jitter accelerations are also investigated and simulated.
Acyclopyrimidine C-nucleosides: Synthesis of 5-[(2,3-dihydroxy-1-propoxy)methyl]pyrimidines†

From the condensation of 5-hydroxymethyluracil and glycerine, 5-[(2,3-dihydroxy-1-propoxy)methyl]uracil (3) was synthesized, which was converted to the isocytosine derivative 9 by the ring-transformation reaction via dimethyluracil derivative 7.
Bayesian Nonparametric Shrinkage Applied to Cepheid Star Oscillations

Bayesian nonparametric regression with dependent wavelets has dual shrinkage properties: there is shrinkage through a dependent prior put on functional differences, and shrinkage through the setting of most of the wavelet coefficients to zero through Bayesian variable selection methods. The methodology can deal with unequally spaced data and is efficient because of the existence of fast moves in model space for the MCMC computation. The methodology is illustrated on the problem of modeling the oscillations of Cepheid variable stars; these are a class of pulsating variable stars with the useful property that their periods of variability are strongly correlated with their absolute luminosity. Once this relationship has been calibrated, knowledge of the period gives knowledge of the luminosity. This makes these stars useful as “standard candles” for estimating distances in the universe.
Particle simulation of vibrated gas- fluidized beds of cohesive fine powders

We have used three-dimensional particle dynamics simulations, coupled with volume-averaged gas phase hydrodynamics, to study vertically vibrated gas-fluidized beds of fine, cohesive powders. The volume-averaged interstitial gas flow is restricted to be one-dimensional (1D). This simplified model captures the spontaneous development of 1D traveling waves, which corresponds to bubble formation in real fluidized beds. We have used this model to probe the manner in which vibration and gas flow combine to influence the dynamics of cohesive particles. We have found that, as the gas flow rate increases, cyclic pressure pulsation produced by vibration becomes more and more significant than direct impact, and in a fully fluidized bed, this pulsation is virtually the only relevant mechanism. We demonstrate that vibration assists fluidization by creating large tensile stresses during transient periods, which helps break up the cohesive assembly into agglomerates.
On Europe's functional constitutionalism Towards a constitutional theory of specialized international regimes

Constitutionalism is enjoying yet another renaissance, this time in the context of supernational institutions. 1 Barring a few holdouts, most observers believe that the answer to the question popular during the late 1990s—is constitutionalism possible beyond the nation-state?— ought to be in the affirmative. At the very least, it has become de rigueur to reach for constitutional language when considering post-national legal entities so long as they bear some resemblance to formal features we associate with constitutionalism. Never mind that these entities (variously taxonomized as regimes, systems, institutions, orders, processes, and so on) have little in common with each other. International institutions ranging from the UN to the WTO, IMF, and ICSID, human rights regimes including the UDHR and the ECHR, juridical constructs such as jus cogens, transnational contract law, and treaties from the Vienna Convention on the Law of Treaties to the New York Convention on the Enforcement of Foreign
Halocyclizations: The cyclization of heterocyclic olefinic amides and ureas

Abstract The halocyclization of N-heterocyclicpentenamides and allylureas with N-bromosuccinimide yields the pyrrolidinones 3 and imidazolidinones 5 , respectively. The thiazolylpentenamide also yields the 6-membered ring lactam.
A Magellanic Origin for the Warp of the Galaxy

We show that a Magellanic Cloud origin for the warp of the Milky Way can explain most quantitative features of the outer H I layer recently identified by Levine et al. We construct a model, similar to that presented by Weinberg in 1998, that produces distortions in the dark matter halo, and we calculate the combined effect of these dark halo distortions and the direct tidal forcing by the Magellanic Clouds on the disk warp in the linear regime. The interaction of the dark matter halo with the disk and resonances between the orbit of the Clouds and the disk account for the large amplitudes observed for the vertical m = 0, 1, and 2 harmonics. The observations lead to six constraints on warp-forcing mechanisms, and our model reasonably approximates all six. The disk is shown to be very dynamic, constantly changing its shape as the Clouds proceed along their orbit. We discuss the challenges to MOND posed by the observations.
Rough-wall layer modeling using the Brinkman equation

A flow model to facilitate the Reynolds-averaged Navier-Stokes (RANS) type of calculations of the turbulent flow over rough walls is proposed. Given that the roughness region is thin compared to the thickness of the boundary layer, the turbulent flow is viewed as consisting of two regions: (1) where the medium is entirely fluid and the RANS equations can be applied, and (2) a region of two phases where the fluid meanders around the solid roughness elements. The method of volume-averaging often used in the study of porous medium flows is applied in the rough-wall layer region. The resulting parameters such as porosity allow a direct inclusion of the geometric characteristics of the roughness element and their pattern in the model equations. In this formulation, the Brinkman equation, a reduced form of the volume-averaged Navier-Stokes (VANS) equations has been used. We have experimented with adapting an existing low Reynolds number eddy-viscosity, two-equation turbulence model developed for smooth walls, t...
TeV Physics and Conformality

Lattice gauge theory has been very successful in deepening our understanding of the strong nuclear interactions. During the past two years, stimulated to some extent by the start-up of the Large Hadron Collider, interest is growing in applying lattice methods to new, strongly interacting theories that could play a role in extending the standard model. I will focus here on the use of lattice methods to study strongly coupled gauge theories with some application to models of dynamical electroweak symmetry breaking.
Supermultiplets of AdS black holes in 2+1 dimensions

Abstract We construct super AdS black holes in 2+1 dimensions in terms of Chern Simons gauge theory of N =(1,1) super AdS group coupled to a (super)source. We take the source to be a super AdS state specified by its Casimir invariants. We show that the corresponding space-time is a supermultiplet of AdS space-times related to each other by supersymmetry transformations. We give explicit expressions for the masses and the angular momenta of the black holes in a supermultiplet. With one exception, for N =(1,1) one pair of extremal black holes can be accommodated in such all-black hole supermultiplets. The requirement that the source be a unitary representation leads to a discrete tower of excited states which provide a microscopic model for the super black hole.
Turbulence: the chief outstanding difficulty of our subject

A review of interesting current topics in turbulence research is decorated with examples of popular fallacies about the behaviour of turbulence. Topics include the status of the Law of the Wall, especially in compressible flow; analogies between the effects of Reynolds number, pressure gradient, unsteadiness and roughness change; the status of Kolmogorov's universal equilibrium theory and local isotropy of the small eddies; turbulence modelling, with reference to universality, pressure-strain modelling and the dissipation equation; and chaos. Fallacies include the mixing-length concept; the effect of pressure gradient on Reynolds shear stress; the separability of time and space derivatives; models of the dissipation equation; and chaos.
Predicting Caco-2 cell permeation coefficients of organic molecules using membrane-interaction QSAR analysis.

A methodology termed membrane−interaction QSAR (MI-QSAR) analysis has been developed in order to predict the behavior of organic compounds interacting with the phopspholipid-rich regions of biological membranes. One important application of MI-QSAR analysis is to estimate ADME properties including the transport of organic solutes through biological membranes as a computational approach to forecasting drug intestinal absorption. A training set of 30 structurally diverse drugs, whose permeability coefficients across the cellular membranes of Caco-2 cells were measured, was used to construct significant MI-QSAR models of Caco-2 cell permeation. Cellular permeation is found to depend primarily upon aqueous solvation free energy (solubility) of the drug, the extent of drug interaction with a model phospholipid (DMPC) monolayer, and the conformational flexibility of the solute within the model membrane. A test set of eight drugs was used to evaluate the predictivity of the MI-QSAR models. The permeation coeffic...
Basic capacity calculation methods and benchmarking for MF-TDMA and MF-CDMA communication satellites

SUMMARY This paper introduces basic capacity calculation methods for circuit switched, multiple-beam, low earth orbit (LEO) communication satellites that use MF-TDMA and MF-CDMA schemes. Capacity is deflned as the number of simultaneous duplex channels that a satellite can support for a given data rate and bit error rate. This paper integrates the bandwidth limit and the power limit on capacity, and derives the equations by which the capacity of a MF-TDMA or a MF-CDMA system can be calculated using key system parameters. Therefore, these methods enable system designers to quickly estimate the communication system capacity when key system parameters are known. The paper uses the Iridium and Globalstar systems for benchmarking by comparing the results obtained from the analytical methods with the 1,100 and 2,5000 simultaneous channels reported by Iridium and Globalstar, respectively. The analytic capacity estimate matches reported single satellite capacities to within 6%, but the predictions are sensitive to various loss assumptions made in the link budget. Copyright c ∞ 2004 John Wiley & Sons, Ltd.
Demystifying Disruption: A New Model for Understanding and Predicting Disruptive Technologies

The failure of firms in the face of technological change has been a topic of intense research and debate, spawning the theory (among others) of disruptive technologies. However, the theory suffers from circular definitions, inadequate empirical evidence, and lack of a predictive model. We develop a new schema to address these limitations. The schema generates seven hypotheses and a testable model relating to platform technologies. We test this model and hypotheses with data on 36 technologies from seven markets. Contrary to extant theory, technologies that adopt a lower attack (“potentially disruptive technologies”) (1) are introduced as frequently by incumbents as by entrants, (2) are not cheaper than older technologies, and (3) rarely disrupt firms; and (4) both entrants and lower attacks significantly reduce the hazard of disruption. Moreover, technology disruption is not permanent because of multiple crossings in technology performance and numerous rival technologies coexisting without one disrupting the other. The proposed predictive model of disruption shows good out-of-sample predictive accuracy. We discuss the implications of these findings.
The Maslov cycle as a Legendre singularity and projection of a wavefront set

A Maslov cycle is a singular variety in the lagrangian grassmannian Λ(V) of a symplectic vector space V consisting of all lagrangian subspaces having nonzero intersection with a fixed one. Givental has shown that a Maslov cycle is a Legendre singularity, i.e. the projection of a smooth conic lagrangian submanifold S in the cotangent bundle of Λ(V). We show here that S is the wavefront set of a Fourier integral distributionwhich is “evaluation at 0 of the quantizations”.
Promoter regions of many neural- and nutrition-related genes have experienced positive selection during human evolution

Surveys of protein-coding sequences for evidence of positive selection in humans or chimpanzees have flagged only a few genes known to function in neural or nutritional processes, despite pronounced differences between humans and chimpanzees in behavior, cognition and diet. It may be that most such differences are due to changes in gene regulation rather than protein structure. Here, we present the first survey of promoter (5'-flanking) regions, which are rich in cis-regulatory sequences, for evidence of positive selection in humans. Our results indicate that positive selection has targeted the regulation of many genes known to be involved in neural development and function, both in the brain and elsewhere in the nervous system, and in nutrition, particularly in glucose metabolism.
Subharmonic generation in quantum systems

Abstract We show how the classical-quantum correspondence permits long-lived subharmonic motion in a quantum system driven by a periodic force. Exponentially small deviations from exact subharmonicity are due to coherent tunneling between quantized vortex tubes which surround classical elliptic periodic orbits.
Surface morphology and electronic properties of ErSi2

Abstract The surface of ErSi 2 , formed by the reaction of thin erbium layers with a single-crystal silicon substrate, is typically dominated by deeply penetrating regularly shaped pits. These pits are shown to have detrimental effects on the electronic performance of Schottky barrier diodes. Surface pits may be reduced in density or eliminated entirely (i) by the use of silicon substrate surfaces prepared under ultrahigh vacuum conditions prior to metal deposition, (ii) by means of ion irradiation techniques or (iii) by reacting erbium with an amorphous silicon (a-Si) layer. In this investigation, planar ErSi 2 layers (pit free) are made using the third approach with a sample structure of a-Si/Er/c-Si where c-Si denotes crystalline silicon. The fast reaction between a-Si and erbium leads to a planar sample structure of ErSi 2 /c-Si with little or no reaction between erbium and the c-Si substrate. The electronic performance of pit-free ErSi 2 diodes made in this manner is shown to be much superior to that of diodes made by reacting erbium with silicon substrates.
Minimax Design of Robust Controllers for Flexible Systems

The design of robust time-delay and saturating controllers based on the range of expected variation of uncertain parameters from their nominal values is investigated. A minimax optimization problem is formulated with the objective of minimizing the maximum value of the cost function over the range of the uncertain parameter. By the adoption of the residual energy as the cost function, the optimization problem formulation is simple because it requires only one equation that is used both as the cost function and constraint. To expedite the optimization process, equations are derived for the gradient of the cost and constraint functions with respect to the parameters of the controller. The proposed technique is illustrated on two examples. The first is a spring-mass-dashpot and the second is the two-mass-spring benchmark problem.
A General Synthetic Procedure for Heteropolyniobates

The heteropolyanions of W, Mo, and V, which have found numerous applications, are formed simply by acidification of solutions of their oxoanions. Under similar conditions, these oxoanion precursors are not available for Nb, and Nb-oxo chemistry is dominated by formation of the Lindquist ion [Nb6O19]8– only. However, heteropolyniobate formation is favored in hydrothermal reactions of aqueous, alkaline precursor mixtures. Here we give two examples of heteropolyniobates formed by this general reaction type: K12[Ti2O2][SiNb12O40]·16H2O [1], which contains chains of silicododecaniobate Keggin ions, and Na14[H2Si4Nb16O56]·45.5H2O [2], a new heteropolyanion structure type.
Why the World Suddenly Cares About Global Supply Chains

The global value chain (GVC) concept has gained popularity as a way to analyze the international expansion and geographical fragmentation of contemporary supply chains and value creation and capture therein. It has been used broadly in academic publications that examine a wide range of global industries, and by many of the international organizations concerned with economic development. This note highlights some of the main features of GVC analysis and discusses the relationship between the core concepts of governance and upgrading. The key dynamics of contemporary global supply chains and their implications for global production and trade are illustrated by: (1) the consolidation of global value chains and the new geography of value creation and capture, with an emphasis on China; (2) the key roles of global supermarkets and private standards in agri-food supply chains; and (3) how the recent economic crisis contributes to shifting end markets and the regionalization of value chains. It concludes with a discussion of the future direction of GVC analysis and a potential collaboration with supply chain researchers.
Offshore Sandstone Reservoir Perforating Practices Used in Saudi Arabia

Perforating wells for production has been a widely accepted industry practice for nearly 50 years. Today, many producing wells are completed with metal casings cemented across hydrocarbon-bearing zones to control oil, gas, water, and solid particle entry into the wellbores. Reservoir fluid flow into wellbores is obtained through perforation tunnels made in casings, cement sheaths, and reservoir rock. Perforation technology and methods of evaluating perforation efficiencies have advanced greatly during the past 50 years. The resulting selection of well perforating devices and perforating methods is vast. However, few studies have been published that address field assessment of well perforating efficiencies. The inability of many oil-producing wells to flow naturally to surface hampers evaluation of their perforation effectiveness. Saudi Arabian offshore oil production is obtained from naturally flowing wells. This situation readily lends itself to analysis of well production profiles and perforation flow efficiencies. This paper examines perforation efficiencies of jet guns in high-production flowing wells. Perforation interval flow profiles, wellbore pressure buildups and productivity index (PI) tests were evaluated for comparison of well perforation efficiencies. Effects of drilling operations and the quality of primary cementation on the well perforation efficiencies were evaluated also.
Government intervention and the structure of social capital

Over the past decade, policymakers and scholars have devoted increasing attention to the nature and role of social capital in the functioning of society. We examine the implications of government attempts to manipulate the existing structure of social capital to create homogeneity among agents. We find that these attempts can weaken, erode or destroy existing social capital. We conclude with policy implications regarding government efforts to create or manipulate social capital.
Characterization of Printer MTF

We develop a comprehensive procedure for characterizing the modulation transfer function (MTF) of a digital printer. Especially designed test pages consisting of a series of patches, each with a different one-dimensional (1D) sinusoidal modulation, enable measurement of the dependence of the MTF on spatial frequency, bias point, modulation amplitude, spatial direction of modulation, and direction of modulation in the color space. Constant tone patches also yield the extreme and center color values for the input modulation. After calibrating the scanner specifically for the direction of modulation in the color space, we spatially project the scanned test patches in the direction orthogonal to the modulation to obtain a 1D signal, and then project these sample points onto a line in the CIE L*a*b* color space between the extreme color values to obtain a perceptually relevant measure of the frequency response in a specific color direction. Appropriate normalization of the frequency response followed by compensation for the scanner MTF completes the procedure. For a specific inkjet printer using a dispersed-dot halftoning algorithm, we examine the impact of the above-mentioned parameters on the printer MTF, and obtain results that are consistent with the expected behavior of this combination of print mechanism and halftoning algorithm.
Testing Relativity with Orbiting Oscillators

Clock-comparison experiments using a satellite platform can give Planck-scale sensitivity to many parameters for Lorentz and CPT violation that are difficult to measure on Earth. A discussion of the theoretical framework for such tests is given, with emphasis on comparisons of output frequencies of atomic clocks and of electromagnetic cavity oscillators.
Cryogenic Frequency Domain Optical Mass Memory.

Cryogenic frequency domain optical memories based upon photochemical hole burning offer the possibility of storing data at densities of up to 1011 bits /cm2. The basic principles of photochemical hole burning are reviewed. Recent results on recording materials, data reading and writing, and configurations are presented.