cssi/SciSciGPT-SciSciNet huggingface dataset:
Sampling-based Falsification and Verification of Controllers for Continuous Dynamic Systems:

In this paper, we present a sampling-based verification algorithm for continuous dynamic systems with uncertainty due to adversaries, unmodeled disturbance inputs, unknown parameters, or initial conditions. The algorithm attempts to find inputs (and resulting trajectories) that falsify the specifications of the system thus providing examples of bad inputs to the system. The system is said to be verified if the algorithm cannot find falsifying inputs.
The Law of Primogeniture and the Transition from Landed Aristocracy to Industrial Democracy

We study the connection between inheritance systems and the historical evolution of the relationship between a society’s economic structure and its political system, with a focus on Europe from feudal times. The model predicts that, in an early agrarian phase, aristocratic political systems prevail, while democracies tend to emerge with industrialization. At the same time, as indivisible landed estates are replaced by capital as the primary source of wealth, the inheritance system evolves endogenously from primogeniture to partition. The dynamics of output, distribution, class structure and political participation are in turn reinforced by the system of intergenerational wealth transmission, with primogeniture tending to concentration and partition to equalization.
Union behavior, industry rents, and optimal policies

Abstract This paper examines the welfare gains from strategic industrial policy in the U.S. steel industry, focusing on the role of capacity utilization and the potential gains from capturing labor rents. With underutilized capacity, strategic policies to capture labor rents lead to an endogenous response that diminishes their importance. On the other hand, reducing domestic labor market distortions results in welfare gains nearly as large as those from the optimal subsidy. This suggests that the focus on labor rents as the subject of industrial policy is overstated, at least in manufacturing industries such as integrated steel.
Image Ellipticity from Atmospheric Aberrations

We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand the errors in shape measurements of astronomical objects, such as those used to study weak gravitational lensing of field galaxies. The PSF modeling involves either a Fourier transform of the phase information in the pupil plane or a ray-tracing approach, which has the advantage of requiring fewer computations than the Fourier transform. Using a standard method, involving the Gaussian-weighted second moments of intensity, we then calculate the ellipticity of the PSF patterns. We find significant ellipticity for the instantaneous patterns (up to more than 10%). Longer exposures, which we approximate by combining multiple (N) images from uncorrelated atmospheric realizations, yield progressively lower ellipticities (as 1/). We also verify that the measured ellipticity does not depend on the sampling interval in the pupil plane using the Fourier method. However, we find that the results using the ray-tracing technique do depend on the pupil sampling interval, representing a gradual breakdown of the geometric approximation at high spatial frequencies. Therefore, ray tracing is generally not an accurate method of modeling PSF ellipticity induced by atmospheric turbulence unless some additional procedure is implemented to correctly account for the effects of high spatial frequency aberrations. The Fourier method, however, can be used directly to accurately model PSF ellipticity, which can give insights into errors in the statistics of field galaxy shapes used in studies of weak gravitational lensing.
Dynamics of a Microsphere in an Anisotropic Gel: a Frontier in Intracellular Microrheology

The cell cytoplasm comprises an anisotropic semi-dilute filamentous network permeated by a liquid. The mechanical properties of this coupled multiphase system play a determinant role in many cell functions, ranging from cell motility to mechanotransduction.Particle Tracking Microrheology estimates the shear modulus of the cell cytoplasm from the measured motion of probing embedded microparticles. It relates the measured resistance of the probes to the viscoelasticity of the medium by assuming Stokes drag. This assumption is crucial to microrheology, but it breaks in live cells due to the structural complexity of the intracellular domain: it has marked anisotropic characteristics. This introduces severe limitations in the application of current microrheological methods to live cells due to our lack of fundamental understanding about the non-Stokesian hydrodynamics of the microrheological probes in anisotropic media.To overcome this limitation, we studied the motion of a microsphere in an anisotropic viscoelastic network (the cytoskeleton), permeated by a background liquid (the cytosol). In the limit of strong coupling between the network and the liquid, the flow around the sphere is modeled with a generalized Stokes equation using up to 5 viscoelasticity parameters. We solve this problem analytically and calculate the flow generated by the sphere and the drag force that it undergoes. Due to the incompressibility of the medium, the drag is influenced by the shear moduli in every direction. Using the calculated drag, we obtain new closed-form microrheology formulae that relate the resistance measured experimentally to the anisotropic properties of the medium. Previously used techniques render an “effective shear modulus”, which is an average of the actual shear modulii. As a result, they highly underestimate the directionality of the mechanical properties for moderately anisotropic media: they render errors in the order of 200%.
Quantized Iterative Message Passing Decoders with Low Error Floor for LDPC Codes

The error floor phenomenon observed with LDPC codes and their graph-based, iterative, message-passing (MP) decoders is commonly attributed to the existence of error-prone substructures - variously referred to as near-codewords, trapping sets, absorbing sets, or pseudocodewords - in a Tanner graph representation of the code. Many approaches have been proposed to lower the error floor by designing new LDPC codes with fewer such substructures or by modifying the decoding algorithm. Using a theoretical analysis of iterative MP decoding in an idealized trapping set scenario, we show that a contributor to the error floors observed in the literature may be the imprecise implementation of decoding algorithms and, in particular, the message quantization rules used. We then propose a new quantization method - (q+1)-bit quasi-uniform quantization - that efficiently increases the dynamic range of messages, thereby overcoming a limitation of conventional quantization schemes. Finally, we use the quasi-uniform quantizer to decode several LDPC codes that suffer from high error floors with traditional fixed-point decoder implementations. The performance simulation results provide evidence that the proposed quantization scheme can, for a wide variety of codes, significantly lower error floors with minimal increase in decoder complexity.
Dynamical systems method for solving linear ill-posed problems

Various versions of the Dynamical Systems Method (DSM) are proposed for solving linear ill-posed problems with bounded and unbounded operators. Convergence of the proposed methods is proved. Some new results concerning the discrepancy principle for choosing the regularization parameter are obtained. 1. Introduction. In this paper we present part of the results from the author's invited plenary talk at the international conference on mathemat- ical analysis and applications ICMAAS06, held in Egypt. This part deals with linear ill-posed problems. Some of the ideas and results in this paper are taken from the papers of the author, cited in the bibliography, but many results are new, including Theorems 2{8 and 10.
Ballooning-Mirror Instability and Internally Driven Pc 4-5 Wave Events

A kinetic-MHD field-aligned eigenmode stability analysis of low frequency ballooning-mirror instabilities has been performed for anisotropic pressure plasmas in the magnetosphere. The ballooning mode is mainly a transverse wave driven unstable by pressure gradient in the bad curvature region. The mirror mode with a dominant compressional magnetic field perturbation is excited when the product of plasma beta and pressure anisotropy (P⊥/P|| > 1) is large. In the limit that the wave frequency is smaller than the energetic trapped particle magnetic drift frequency, which is usually much smaller than the energetic trapped particle bounce frequency, the energetic trapped particles experience the bounce-averaged wave structure due to their rapid bounce motion. For modes with north-south symmetric field-aligned structure of parallel perturbed magnetic field the energetic trapped particle kinetic pressure response is finite and cancels with their fluid pressure response so that the symmetric mode is stable. Physically the energetic trapped particles precess very rapidly across the B field, and their motion becomes very rigid with respect to low frequency symmetric MHD perturbations. For antisymmetric modes the energetic trapped particle kinetic pressure response from the northern hemisphere cancels with that from the southern hemisphere in a bounce period, and the instability β threshold of the antisymmetric mode is determined by the energetic particle fluid free energy. Pressure anisotropy with P⊥/P|| > 1 reduces the β|| threshold. The antisymmetric mode changes from a ballooning mode with dominant transverse magnetic field components at P⊥/P|| = 1 to a hybrid ballooning-mirror type mode with comparable transverse and compressional magnetic field components near the equator as P⊥/P|| increases. With large equatorial plasma beta (β|| ≥ Ο(1)) and pressure anisotropy (P⊥/P|| > 1) the field-aligned wave structure of antisymmetric ballooning-mirror mode resembles the multisatellite observations of a long lasting compressional Pc 5 wave event during November 14-15, 1979 (Takahashi et al., 1987). From the AMPTE/ CCE particle and magnetic field data observed during Pc 4-5 wave events we compute the ballooning-mirror instability parameters and perform a correlation study with the theoretical instability threshold. We find that compressional Pc 5 waves approximately satisfy the ballooning-mirror instability condition, and transverse Pc 4-5 waves are probably related to resonant ballooning instabilities with small pressure anisotropy.
Neonatal seizures: eyes open or closed?

Summary: Purpose: It has been shown that persistent eye closure during paroxysmal events in infants makes seizures unlikely. Our study aims to assess whether this is also true in neonates. Methods: We reviewed and classified all archived neonatal seizures in our video database, considering electroclinical seizures only and excluding electrographic seizures and clinical seizures without ictal change in EEG. We assessed whether eyes were open during the seizure. One hundred and thirty-one electroclinical seizures (clonic, focal and generalized tonic, tonic–clonic, generalized myoclonic, subtle and spasms) in 46 neonates were included. Results: In 115 (88%) seizures, eyes were open; in 10 seizures, they were closed; and in six seizures, eye opening could not be evaluated. All 10 seizures with persistent eye closure were clonic seizures. Conclusions: Our data demonstrate that persistent eye closure during an event suggestive of a seizure in a newborn makes an electroclinical seizure unlikely.
Majorana neutrino masses from neutrinoless double beta decay and cosmology

Abstract When three Majorana neutrinos describe the solar and atmospheric neutrino data via oscillations, a nonzero measurement of neutrinoless double beta (0 νββ ) decay can determine the sum of neutrino masses ∑ m ν if the solar solution has small-angle mixing, and place a lower bound on ∑ m ν for large-angle solar mixing. If in addition a nonzero ∑ m ν is deduced from cosmology, the neutrino mass spectrum may be uniquely specified for some ranges of neutrino parameters. For ∑ m ν >0.75 eV, the small-angle solar solution is excluded by the current upper limit on neutrinoless double beta decay. In models with maximal solar mixing the CP phases of the neutrinos may be strongly constrained by stringent upper bounds on 0 νββ decay.
Sense.us: Towards a more social ‘social visualization’

The present research analyses the ‘social visualization’ tool Sense.us, a commercial interactive Web application in which U.S. Census data are being visualized. Sense.us was developed as a tool for social data exploration and interaction, in which it would be worthwhile to pay attention to the socio-cultural values that have driven the collection and categorization of the underlying U.S. Census datasets. It is argued that closer attention to value-driven U.S. Census statistics would greatly enhance the social appeal of Sense.us, and would be a logical next step in the development of online social visualization tools. In order to allow for explicit socio-cultural values of statistics in online visualizations, three strategies are offered: pro-active annotation; more attention to visual aesthetics; and, a tighter integration of user profiles and represented data.
4,5-Diphenylimidazoles from the Cyclization of Benzil N-Alkylmonohydrazones

The thermal cyclization of monodisubstituted hydrazones (1) affords the corresponding N-substituted-4,5-diphenylimidazoles in good to excellent yields; possible mechanisms for this unusual cyclization are presented.
The source of holes in p-type InxGa1-xN films

Mg-doped In x Ga 1-x N films are investigated using electron paramagnetic resonance (EPR) spectroscopy. Surprisingly, the number of EPR-detected Mg-related acceptors decreases as x increases from 0.021 to 0.112, but the hole density increases as expected. The observation is attributed to the loss of a magnetic resonance signal from Mg impurities in the vicinity of an In-induced perturbing field. Analysis shows that the number of Mg affected is greater than the amount predicted by considering only next nearest neighbors, but does not extend to all the Mg atoms. The results support the model in which In-induced potential fluctuations perturb the Mg dopant.
Use of monocular groupings and occlusion analysis in a hierarchical stereo system

We describe a hierarchical stereo system that computes a hierarchy of descriptions up the surface level from each view using a perceptual grouping technique and matches these features at the different levels. With the description and correspondence processes going hand in hand, we allow high-level abstract features to help reduce correspondence ambiguities, and we exploit the multiple views to help confirm the different levels of descriptions in the scene. Occlusion is a major problem in stereo analysis and is often not treated explicitly. We present a basic property of occlusions in stereo views and show how we can use this property incorporated with the structural descriptions to identify different types of occlusions in the scene. In particular, we identify depth discontinuities and limb boundaries and infer properties of surfaces that are visible only in one of the stereo views. We give some experimental results on scenes with curved objects and with multiple occlusions.
Homogenization of elliptic boundary value problems in Lipschitz domains

In this paper we study the L p boundary value problems for $${\mathcal{L}(u)=0}$$ in $${\mathbb{R}^{d+1}_+}$$ , where $${\mathcal{L}=-{\rm div} (A\nabla )}$$ is a second order elliptic operator with real and symmetric coefficients. Assume that A is periodic in x d+1 and satisfies some minimal smoothness condition in the x d+1 variable, we show that the L p Neumann and regularity problems are uniquely solvable for 1 < p < 2 + δ. We also present a new proof of Dahlberg’s theorem on the L p Dirichlet problem for 2 − δ < p < ∞ (Dahlberg’s original unpublished proof is given in the Appendix). As the periodic and smoothness conditions are imposed only on the x d+1 variable, these results extend directly from $${\mathbb{R}^{d+1}_+}$$ to regions above Lipschitz graphs. Consequently, by localization techniques, we obtain uniform L p estimates for the Dirichlet, Neumann and regularity problems on bounded Lipschitz domains for a family of second order elliptic operators arising in the theory of homogenization. The results on the Neumann and regularity problems are new even for smooth domains.
Improved prospects for rural development: an industrial targeting system for the Great Plains

This research introduces an industrial targeting system intended to improve local decision making related to selection of targets for business recruitment. The Plains Economic Targeting System (PETS) consists of a series of econometric equations that match industry input and market requirements with community characteristics to generate a probability of new business location over a given time period. The system matches location requirements for 78 industry sectors to local characteristics for 414 counties in six Great Plains states. Further, the coefficients generated for a given county are transformed into marginal impacts, providing important information relating to local policies that can improve the probability of attracting a given industry.
Variance of streaming potential measurements

We evaluated sources of variance in the measurement of the surface streaming potential of flat sheet specimens of cellulose di/triacetate membranes with a commercial electrokinetic analyzer. Two measurement methods were evaluated: the instrument's standard operating procedure, which continuously ramps the flow past the specimen, and a modified procedure that periodically stepped the flow rate and required manual calculation of zeta potential from the archived pressure and streaming potential data. Our study indicated that the kinetics of equilibration between electrolyte, electrodes, and membrane has the greatest impact on measurement uncertainty of any method used. An optimized protocol was developed for each method and the type A uncertainty (standard deviation) for the data collected using the optimized, modified procedure was one-third the value obtained using the optimized, standard procedure.
High-speed digital-to-analog conversion by integration of a variable-rate pulse train

The conversion of a binary number into an analog voltage, current, or shaft position is a basic problem which must be solved in a wide variety of digital control systems. Because of this widespread need, many techniques have been devised, each with individual limitations and shortcomings. A conversion of digits-to-shaft position can be made by comparing the digital representation from a code wheel with the binary number to be converted. The shaft attached to the code wheel is made to rotate until the reading obtained from it agrees with the number to be converted. The code wheel reading is subtracted from the number to be converted, and the difference quantity generates an analog error voltage which controls a servo connected to the shaft of the code wheel. A digit-to-voltage or current conversion may be accomplished by the method illustrated in Fig. 1. The principle is that of assigning appropriate analog weights to each binary digit. The individual analog quantities are essentially voltages or currents which are proportional to the significance of the respective digits in the numbering system. The conversion is effected by summing up the analog equivalent for each digit containing a binary one in the number being converted. In Fig. 1, the conversion is to an analog current, I0, proportional to the binary number, represented by the switch settings. The binary number represented by the switch setting in this figure corresponds to 000101. It will be noted that the current produced is 5/64 E/R. Another system which should be mentioned, because at first glance it appears similar to the one to be described, is the Shannon-Rack converter. In this system, the binary representation of the number to be converted is sampled serially, starting with the lowest-order digit and proceeding to the highest. As the digits are shifted out of the register containing the number, a one digit will cause a pulse to be generated into a shunt RC circuit. The time constant of the RC network is such that in a digit pulse period the charge on the capacitor will decay to one-half of its initial value. Therefore, after n pulse periods, the charge remaining due to a one occurring at the first pulse time is proportional to 1/2n-1. The exponential decay provides a convenient method of obtaining the appropriate binary weight. The voltage across the capacitor, one pulse period after the most significant digit has been shifted out, will equal a voltage proportional to the digital number which was contained in the register. A simplified circuit of this system is shown in Fig. 2. The circuit consists of a constant current source, a switch, a resistor, and a capacitor. The switch is controlled by the output of the register containing the number being converted. It is closed for a given period of time as each one is shifted from the register.
A quasi-Newton method for large scale support vector machines

This paper adapts a recently developed regularized stochastic version of the Broyden, Fletcher, Goldfarb, and Shanno (BFGS) quasi-Newton method for the solution of support vector machine classification problems. The proposed method is shown to converge almost surely to the optimal classifier at a rate that is linear in expectation. Numerical results show that the proposed method exhibits a convergence rate that degrades smoothly with the dimensionality of the feature vectors.
Failure Analysis of Woven and Braided Fabric Reinforced Composites

A general purpose micromechanics analysis that discretely models the yarn architecture within the textile repeating unit cell was developed to predict overall, three-dimensional, thermal and mechanical properties, damage initiation and progression, and strength. This analytical technique was implemented in a user-friendly, personal computer-based, menu-driven code called Textile Composite Analysis for Design (TEXCAD). TEXCAD was used to analyze plain weave and 2 × 2, 2-D triaxial braided composites. The calculated tension, compression, and shear strengths correlated well with available test data for both woven and braided composites. Parametric studies were performed on both woven and braided architectures to investigate the effects of parameters such as yarn size, yarn spacing, yarn crimp, braid angle, and overall fiber volume fraction on the strength properties of the textile composite.
Moving beyond the direct effect of SFA adoption on salesperson performance: training and support as key moderating factors

Abstract To our knowledge, this research is the first to focus on the critical moderating role that user training and support play on the relationship between the use of sales force automation tools and salesperson performance (i.e., effectiveness: percent-to-quota and efficiency: average number of calls per day). Hypotheses are tested using survey data from a sample of 108 salespeople in a business-to-business context and archival sales performance information. Moderated regression analysis results indicate that the use of sales force automation tools only enhances salesperson efficiency and effectiveness under conditions of adequate user support and training. In fact, under low levels of user training and support, the use of sales force automation tools was found to reduce salesperson efficiency and effectiveness. These findings have important implications for IT and sales managers since the results show that only under certain conditions will companies realize a return on their investment in SFA tools. Limitations and future directions for research are then discussed.
Effect of interfaces and the spin-orbit band on the band gaps of InAs/GaSb superlattices beyond the standard envelope-function approximation

We develop a modified $8\ifmmode\times\else\texttimes\fi{}8$ envelope-function approximation (EFA) formalism for the noncommon-atom (NCA) superlattices (SL's), incorporating the effect of anisotropic and other interface (IF) interactions that go beyond the standard EFA. The boundary conditions in the presence of IF interactions are used to set up a secular equation (including a transfer matrix derivation) whose physical transparency makes possible a number of valuable insights (possibility of IF bound states, analytic solutions, indirect gaps, etc.). We show that the heavy-hole--spin-orbit IF coupling is very important due to the IF localization of the SO wave function components and the ability of the IF potential to potentially bind a hole at the IF's, all of which pose convergence problems for perturbative solutions. With two adjustable parameter for the two possible IF's, we find a very good agreement between experiment and theory for the band gaps of several sets of very long-infrared and midinfrared InAs/GaSb SL's grown at several laboratories and by us. The band gaps as a function of GaSb and InAs widths are explained in terms of variations of the HH and conduction (C) band bandwidths. We show that the cut-off wavelengths can be reduced by increasing the GaSb layer width. Thus, a consistent application of the EFA method with the inclusion of well established IF effects can provide useful physical insights and possesses good predictive capacity in the design of NCA SL's.
Neurobiological computational models in structural analysis and design

This paper examines the role of neural computing strategies in structural analysis and design. A principal focus of the work resides in the use of neural networks to represent the force-displacement relationship in static structural analysis. Such models provide computationally efficient capabilities for reanalysis, and appear to be well suited for application in numerical optimum design. The paper presents an overview of the neutral computing approach, with special emphasis on supervised learning techniques adopted in the present work. Special features of such learning strategies which have a direct bearing on numerically accuracy and efficiency, are examined in the context of representative structural optimization problems.
A cytosine analogue containing a conformationally flexible acyclic linker for triplex formation at sites with contiguous G-C base pairs

Abstract Two nucleoside derivatives of the pyrimidine bases T and m 5ox C have been prepared with flexible acyclic carbohydrate linkers. A new procedure, beginning with ( R )-(−)-2,2-dimethyl-1,3-dioxolane-4-methanol permits the preparation of the stereochemically pure acyclic derivatives of both protected nucleoside analogues without contamination by a problematic rearrangement product. By simply increasing the flexibility of the carbohydrate portion of the am 5ox C nucleoside derivative, 15-mer triplexes containing five contiguous G-C base pairs exhibit a 7–8°C increase in T m value.
Hot-wire measurements in the hypersonic wakes of slender bodies

An exploratory study of the viscous wake of right-angle two-dimensional wedges have been made with a hot-wire anemometer at a Mach number of 6 The main emphasis was placed on studying the transition to turbulence and the lateral spreading of the turbulent wake The laminar near-wake thickness was found to be constant, but upon transition the wake spread laterally quite rapidly The distance between the model and the transition zone showed a Reynolds-number dependence reminiscent of that found for blunt bodies The near wake of the wedges, however, is strongly stabilized by the large lateial Mach number gradient The transition Reynolds number was found to be independent of body size but dependent on the wedge angle Meaningful comparisons were made with transition data obtained with blunt bodies Also, very reasonable similarities were found to exist between these data and i esults of expei iments with cones fired in ballistic ranges HE hypersonic wakes of slender bodies have several features distinguishing them from wakes behind blunt-bluff bodies Strong flow gradients generated by bow shocks are largely absent around slender bodies, with the result that the viscous wake gro\vs into a region where the flow quantities are close to those of the freestream For this reason both the transition to turbulence and the growth of the slender body wake, and perhaps the magnitude of its turbulent fluctua tions, should be different for these two types of geometries at least in an outward sense Optical observations of the viscous wake of cones have been reported by Slattery1 and Pallone et al 2 These data are useful as qualitath e indicators of the over-all flow field, the region of transition to turbulence, and the thickness of the laminar and turbulent wake In a preliminary way they indicate that the distance between the transition zone and the body increases with decreasing ambient pressure, a phenomenon also observed with blunt-bluff bodies 3 However, Slattery's cone data show a clear dependence of the transition distance on flight velocity l This effect is much stronger than observed with spheres; in fact the Reynolds number of transition for blunt bodies was found3 to be almost linearly related to the flight Mach number so that the velocity dependence disappeared Further, judging from the results of Ref 1 the transition distance for the cones again does not scale with the body size, a result already obtained with the blunt-bluff configurations 3 Finally, these preliminary transi
Kinetic anomalies in addition-aggregation processes

We investigate irreversible aggregation in which monomer–monomer, monomer–cluster and cluster–cluster reactions occur with constant but distinct rates KMM, KMC and KCC, respectively. The dynamics crucially depends on the ratio γ = KCC/KMC and secondarily on = KMM/KMC. For = 0 and γ k*. When > 0, analogous behaviours emerge for γ < 2 and γ ≥ 2.
Nuclear Magnetic Resonance Studies of Macroscopic Morphology and Dynamics

Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample`s density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with amore » coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques.« less
Control-Surface Reversal in the Transonic Regime

This paper investigates control surface reversal in the transonic flight regime. Linear and nonlinear rigid and aeroelastic analyses are performed to examine the effects of including flow nonlinearities in the prediction of this aeroelastic phenomenon. Transonic small disturbance theory is employed in the analysis of a simple rectangular wing and a typical fighter type wing to study the interactions among control surface deflections, structural flexibility, and embedded shocks in the flow field. Pressure distributions on the wings are examined. Rigid rolling moment calculations are presented, followed by control surface effectiveness and control surface reversal trends as the Mach number is varied from a subsonic value, through the transonic regime, into the supersonic region. These results are discussed based on the predictions of the pressure coefficients generated by the solution of the transonic small-disturbance equation. Finally, generalizations are presented about the effects of including aerodynamic nonlinearities in the prediction% of steady aeroelastic phenomenon in transonic flow conditions.
Modeling and forecast of the polar motion excitation functions for short-term polar motion prediction

Short-term forecast of the polar motion is considered by introducing a prediction model for the excitation function that drives the polar motion dynamics. The excitation function model consists of a slowly varying trend, periodic modes with annual and several sub-annual frequencies (down to the 13.6-day fortnightly tidal period), and a transient decay function with a time constant of 1.5 days. Each periodic mode is stochastically specified using a second-order auto-regression process, allowing its frequency, phase, and amplitude to vary in time within a statistical tolerance. The model is used to time-extrapolate the excitation function series, which is then used to generate a polar motion forecast dynamically. The skills of this forecast method are evaluated by comparison to the C-04 polar motion series. Over the lead-time horizon of four months, the proposed method has performed equally well to some of the state-of-art polar motion prediction methods, none of which specifically features forecasting of the excitation function. The annual mode in the χ2 component is energetically the most dominant periodicity. The modes with longer periods, annual and semi-annual in particular, are found to contribute more significantly to forecast accuracy than those with shorter periods.
Resveratrol as a new type of DNA-cleaving agent.

Abstract The first demonstration of DNA cleavage by resveratrol ‘3,5,4′-trihydroxy- trans -stilbene’ is presented. Resveratrol mediated relaxation of pBR322 at micromolar concentrations in the presence of Cu 2+ . Evidence is provided that resveratrol is capable of binding to DNA, and that the Cu 2+ -dependent DNA damage is more likely caused by a copper-peroxide complex rather than by a freely diffusible oxygen species.
Landau damping of spin waves in trapped boltzmann gases

A semiclassical method is used to study Landau damping of transverse pseudo-spin waves in harmonically trapped ultracold gases in the collisionless Boltzmann limit. In this approach, the time evolution of a spin is calculated numerically as it travels in a classical orbit through a spatially dependent mean field. This method reproduces the Landau damping results for spin-waves in unbounded systems obtained with a dielectric formalism. In trapped systems, the simulations indicate that Landan damping occurs for a given spin-wave mode because of resonant phase space trajectories in which spins are “kicked out” of the mode (in spin space). A perturbative analysis of the resonant and nearly resonant trajectories gives the Landau damping rate, which is calculated for the dipole and quadrupole modes as a function of the interaction strength. The results are compared to a numerical solution of the kinetic equation by Nikuni et al.
Estimating the Mean of a Correlated Binary Sequence with an Application to Discrete Event Simulation

Abstract : This paper discusses a procedure for interval estimation of the mean theta of a correlated binary (0,1) sequence. The method assumes that the sequence is strictly stationary and that a particular string of m binary digits is a recurrent event in the sequence, where mor = to 1 is unknown. Of the 2 m squared choices for the possible recurrent events, the strings of all zeros and of all ones are examined.
Metabolic factors limiting performance in marathon runners.

Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as ‘hitting the wall’), and thousands drop out before reaching the finish lines (approximately 1–2% of those who start). Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making ‘hitting the wall’ seem inevitable), or implied that maximal glycogen loading is required in order to complete a marathon without ‘hitting the wall.’ The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity) of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding ‘the wall.’ The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.
Closed-form solutions for polygon-based node motion estimation

Motion compensation using 2-D mesh models requires computation of the parameters of a spatial transformation within each mesh element (patch). It is well known that the parameters of an affine (bilinear or perspective) mapping can be uniquely estimated from three (four) node-point motion estimates. This paper presents closed-form overdetermined solutions for least squares estimation of the motion parameters, which also preserve mesh-connectivity using node-based connectivity constraints. In particular, two new algorithms are presented: The first method, based on the dense motion estimates, can be viewed as post processing of the dense motion field for best compact representation in terms of irregularly spaced samples, while the second one, which is based on spatio-temporal intensity gradients, offers closed- form solutions for direct estimation of the best node-point motion vectors. We show that the performance of the proposed closed-form solutions are comparable to those of the alternative search-based solutions at a fraction of the computational cost.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Surface plasmon polariton propagation around bends at a metal-dielectric interface

A short-wavelength analysis for the transmission coefficients of surface plasmon polaritons around a finite-radius metallic bend shows lower losses than on flat surfaces may occur. The maximum transmittance depends non-monotonically on the bend radius
A unique decomposition result for HT factors with torsion free core

We prove that II1 factors M have a unique (up to unitary conjugacy) cross-product type decomposition around “core subfactors” N⊂M satisfying the property HT of [S. Popa, On a class of type II1 factors with Betti numbers invariants, Ann. of Math. (2) 163 (2006) 809–899] and a certain “torsion freeness” condition. In particular, this shows that isomorphism of factors of the form Lαi(Z2)⋊Fni, i=1,2, for Fni⊂SL(2,Z) free groups of rank ni and αj=e2πitj, tj∉Q, implies n1=n2.
Preparation of 2-hydroxy-1,2-diphenylethyl phenylphosphinate: a chiral reagent for asymmetric reduction of ketones

Abstract 2-hydroxy-1,2-diphenylethyl phenylphosphinate has been prepared in 85% yield and 84% d.e. at the phosphorus atom from ( R,R )-hydrobenzoin, and has been found to reduce electron-deficient ketones under mild conditions in up to 95% yield and 43% e.e.
Dynamical Heterogeneity and Jamming in Glass-Forming Liquids †

The relationship between spatially heterogeneous dynamics (SHD) and jamming is studied in a glass-forming binary Lennard-Jones system via molecular dynamics simulations. It has been suggested [Phys. ReV. Lett. 2001, 86, 111] 1 that the probability distribution of interparticle forces P(F) develops a peak at the glass transition temperature Tg and that the large force inhomogeneities, responsible for structural arrest in granular materials, are related to dynamical heterogeneities in supercooled liquids that form glasses. It has been further suggested that “force chains” present in granular materials may exist in supercooled liquids and may provide an order parameter for the glass transition. Our goal is to investigate the extent to which the forces experienced by particles in a glass-forming liquid are related to SHD and compare these forces to those observed in granular materials and other glass-forming systems. Our results are summarized as follows. We calculate P(F) for positive (repulsive) instantaneous forces and find no peak in P(F) at any temperature in our system, even below Tg. We also find that particles that have been localized for a long time are less likely to experience high relative force and that mobile particles experience higher relative forces at shorter time scales, indicating a correlation between pairwise forces and particle mobility. We construct force chains based on the magnitude of pairwise positive instantaneous forces. We find that force chains constructed in this manner are composed of both localized and mobile particles; therefore there is no one-to-one correspondence between force chains as defined here and locally mobile or immobile regions of the liquid. We also find that force chains do not play the same role as force chains in granular materials but may indicate a difference in the evolution of the local environment of particles with different mobility. We also discuss a possible relationship between force chains found here and the development of stringlike motion found in this and other glass-forming liquids [Phys. ReV. Lett. 1998, 80, 2338; J. Chem. Phys. 2004, 120, 4415]. 2,3
A power model for routers: modeling Alpha 21364 and InfiniBand routers

As interconnection networks proliferate to many new applications, a low-latency high-throughput fabric no longer suffices. An architectural-level power model for interconnection network routers will let researchers and designers easily factor in power when exploring architectural tradeoffs.
Feedback in the Antennae Galaxies (NGC 4038/9). I. High-Resolution Infrared Spectroscopy of Winds from Super Star Clusters

We present high-resolution (R {approx} 24,600) near-IR spectroscopy of the youngest super star clusters (SSCs) in the prototypical starburst merger, the Antennae Galaxies. These SSCs are young (3-7 Myr old) and massive (10{sup 5}-10{sup 7} M{sub {circle_dot}} for a Kroupa IMF) and their spectra are characterized by broad, extended Brackett {gamma} emission, so we refer to them as emission-line clusters (ELCs) to distinguish them from older SSCs. The Br {gamma} lines of most ELCs have supersonic widths (60-110 km s{sup -1} FWHM) and non-Gaussian wings whose velocities exceed the clusters escape velocities. This high-velocity unbound gas is flowing out in winds that are powered by the clusters massive O and W-R stars over the course of at least several crossing times. The large sizes of some ELCs relative to those of older SSCs may be due to expansion caused by these outflows; many of the ELCs may not survive as bound stellar systems, but rather dissipate rapidly into the field population. The observed tendency of older ELCs to be more compact than young ones is consistent with the preferential survival of the most concentrated clusters at a given age.
Modelling of the Two-Way Shape Memory Effect

After detailed analyses ofthe microstructural mechanism and training methods ofthe two-way shape memory effect, a further refinement of the transformation kinetic expressions for shape memory alloys (SMAs) is derived. A one-dimensional thermomechanical constitutive model for the two-way effect which undergoes thermoelastic martensitic transformation and its reverse transformation is presented based on the one-way effect model of Liang and Rogers. This model reflects the essence of SMAs in a very simple form and therefore is easy to use in engineering design. It is revealed that the material parameters required by this model can be calculated or measured using standard material testing apparatus. The computer simulation results are in agreement with the experimental data that has been published in the open literature. It is demonstrated that the theory developed can quantitatively predict and describe the behaviour of SMAs and be imposed on the two-way shape memory effect.
Urban Marginality in the Coming Millennium

This paper sketches a characterisation of the regime of urban marginality that has emerged in advanced societies since the close of the Fordist era, highlighting four logics that combine to produce...
Conformationally Complex π‐Conjugated Molecular and Polymeric Materials: New Challenges for Organic Synthesis

Conformational influences profoundly impact the performance of organic electronic materials and the reactivity of organic molecules. We recently found that the expected former consideration was uniquely accompanied by the latter. This report describes a surprisingly regioselective bromination that suggests the general use of conformation as a protecting group during complex molecule synthesis.
Homology of classical lie groups made discrete, III

The present work continues earlier investigations by DuPont, Parry and this writer. One of our motivating problems is the Scissors Congruence Problem (or Extended Third Problem of Hilbert). In 3-dimensional hyperbolic and spherical spaces, this problem has a close relation with the Quillen algebraic Ks-group of iF where [F denotes one of the three classical real division algebras R, C or IH. This relation arises by way of the third integral Eilenberg-MacLane homology group of the classical group SL(2, [F), homology stabilization theorems and the theorem of Hurewicz. The principal results are summarized below. Let D be one of the three real division algebras or any infinite field F with Fx=(Fx)6. In simplified form, we have
All the GIT quotients at once

Let G be an algebraic torus acting on a smooth variety V. We study the relationship between the various GIT quotients of V and the symplectic quotient of the cotangent bundle of V.