cssi/SciSciGPT-SciSciNet huggingface dataset:
Cross-layer jamming detection and mitigation in wireless broadcast networks

Wireless communication systems are often susceptible to the jamming attack where adversaries attempt to overpower transmitted signals by injecting a high level of noise. Jamming is difficult to mitigate in broadcast networks because transmitting and receiving are inherently symmetric operations: A user that possesses the key to decode a transmission can also use that key to jam the transmission. We describe a code tree system that provides input to the physical layer and helps the physical layer circumvent jammers. In our system, the transmitter has more information than any proper subset of receivers. Each receiver cooperates with the transmitter to detect any jamming that affects that receiver. In the resulting system, each benign user is guaranteed to eliminate the impact of the attacker after some finite number of losses with arbitrarily high probability. We show that any system that relies on only using spreading code, and no other physical factors, to mitigate jamming must use at least j + 1 codes, where j is the number of jammers. We then propose an optimized scheme that is power-efficient: Each transmission is sent on at most 2j+1 codes simultaneously. Finally, we demonstrate that our scheme approaches the best possible performance by performing an extensive analysis of the system using both event-driven ns-2 and chip-accurate MATLAB simulations.
Behaviorism at fifty

Each of us is uniquely subject to certain kinds of stimulation from a small part of the universe within our skins. Mentalistic psychologies insist that other kinds of events, lacking the physical dimensions of stimuli, are accessible to the owner of the skin within which they occur. One solution often regarded as behavioristic, granting the distinction between public and private events and ruling the latter out of consideration, has not been successful. A science of behavior must face the problem of privacy by dealing with events within the skin in their relation to behavior, without assuming they have a special nature or must be known in a special way.The search for copies of the world within the body (e.g. the sensations and images of conscious content) has also had discouraging results. The organism does not create duplicates: Its seeing, hearing, smelling, and so on are forms of action rather than of reproduction. Seeing does not imply something seen. We know that when we dream of wolves, no wolves are actually there; it is harder to understand that not even representations of wolves are there.Mentalistic formulations create mental way stations. Where experimental analyses examine the effects of variables on behavior, mentalistic psychologies deal first with their effects on inferred entities such as feelings or expectations and then with the effects of these entities on behavior. Mental states thus seem to bridge gaps between dependent and independent variables, and mentalistic interpretations are particularly attractive when these are separated by long time periods. The practice confuses the order of events and leads to unfinished causal accounts.
The crystallography of strange quark matter

Cold three-flavour quark matter at large (but not asymptotically large) densities may exist as a crystalline colour superconductor. We explore this possibility by calculating the gap parameter Δ and free energy Ω(Δ) for possible crystal structures within a Ginzburg–Landau approximation, evaluating Ω(Δ) to order Δ6. We develop a qualitative understanding of what makes a crystal structure stable and find two structures with particularly large values of Δ and the condensation energy, within a factor of 2 of those for the CFL phase known to characterize QCD at asymptotically large densities. The robustness of these phases results in their being favoured over wide ranges of density and though it also implies that the Ginzburg–Landau approximation is not quantitatively reliable, previous work suggests that it can be trusted for qualitative comparisons between crystal structures. We close with a look ahead at the calculations that remain to be done in order to make contact with observed pulsar glitches and neutron star cooling.
The C–polynomial of a knot

In an earlier paper the first author defined a non-commutative A‐polynomial for knots in 3‐space, using the colored Jones function. The idea is that the colored Jones function of a knot satisfies a non-trivial linear q ‐difference equation. Said differently, the colored Jones function of a knot is annihilated by a non-zero ideal of the Weyl algebra which is generalted (after localization) by the non-commutative A‐polynomial of a knot. In that paper, it was conjectured that this polynomial (which has to do with representations of the quantum group Uq.sl2/) specializes at qD 1 to the better known A‐polynomial of a knot, which has to do with genuine SL2.C/ representations of the knot complement. Computing the non-commutative A‐polynomial of a knot is a difficult task which so far has been achieved for the two simplest knots. In the present paper, we introduce the C ‐polynomial of a knot, along with its non-commutative version, and give an explicit computation for all twist knots. In a forthcoming paper, we will use this information to compute the non-commutative A‐polynomial of twist knots. Finally, we formulate a number of conjectures relating the A, the C ‐polynomial and the Alexander polynomial, all confirmed for the class of twist knots. 57N10; 57M25
The Temperature of the Cosmic Microwave Background

The Far InfraRed Absolute Spectrophotometer data are independently recalibrated using the Wilkinson Microwave Anisotropy Probe data to obtain a cosmic microwave background (CMB) temperature of 2.7260 ± 0.0013. Measurements of the temperature of the CMB are reviewed. The determination from the measurements from the literature is CMB temperature of 2.72548 ± 0.00057 K.
Age-dependent sensitization to oxidative stress by dietary fatty acids.

Experiments were designed to test the hypothesis that short-term feeding of a high polyunsaturated fatty acid (PUFA) diet would increase susceptibility to lipid peroxidation in an agedependent manner. Young (6 month) and old (24 month) male B6C3F1 mice were fed modified AIN-76 diets containing either 5% corn oil (CO, N=5 per age group) or 19% fish oil plus 1% corn oil (FO, N=20 per age group) for two weeks. Five CO and five FO diet mice per age received an intraperitoneal injection of normal saline and were sacrificed one hour later; the remaining FO diet mice (N=15 per age) were challenged with an acute systemic oxidative stress by intraperitoneal injection of 125 mg iron/kg body weight as iron dextran, and were sacrificed 1, 5, and 24 hours post-injection. Microsomal membrane fatty acid analysis revealed that increased age and a FO diet significantly increased membrane PUFA content. Serum iron levels increased significantly following iron treatment, peaking at 5 hours in both age groups. Formation of microsomal malondialdehyde (MDA), a product of lipid peroxidation, was significantly greater in the livers of the young mice. The temporal patterns of serum iron and microsomal MDA concentrations were significantly correlated in young mice, but not in old mice. Histochemical examination showed that liver iron accumulation following iron injection was similar in both age groups, but was associated with a significant temporal increase in liver apoptotic cells in young mice, but not in old mice. Thus, both age groups had similar iron exposure and iron accumulation, and the liver microsomal membranes of old mice were more unsaturated, yet there was significantly greater peroxidative damage (MDA formation) and cell death (apoptosis) in the young mouse livers. These findings suggest that the older animals have upregulated antioxidant defenses.
Addressing model bias and uncertainty in three dimensional groundwater transport forecasts for a physical aquifer experiment

[1] This work contributes a combination of laboratory-based aquifer tracer experimentation and bias-aware Ensemble Kalman Filtering (EnKF) to demonstrate that systematic modeling errors (or bias) in source loading dynamics and the spatial distribution of hydraulic conductivity pose severe challenges for groundwater transport forecasting under uncertainty. The impacts of model bias were evaluated using an ammonium chloride tracer experiment conducted in a three dimensional laboratory tank aquifer with 105 near real-time sampling locations. This study contributes a bias-aware EnKF framework that (i) dramatically enhances the accuracy of concentration breakthrough forecasts in the presence of systematic, spatio-temporally correlated modeling errors, (ii) clarifies in space and time where transport gradients are maximally impacted by model bias, and (iii) expands the size and scope of flow-and-transport problems that can be considered in the future.
A network performance sensitivity metric for parallel applications

Excessive run time variability of parallel application codes on commodity clusters is a significant challenge. To gain insight into this problem, our earlier work developed tools to emulate parallel applications (PACE) by simulating computation and using the cluster's interconnection network for communication, and further study parallel application run time sensitivity effects to controlled network performance degradation (PARSE). This work expands our previous efforts by presenting a metric derived from PARSE test results conducted on several widely used parallel benchmarks and application code fragments. The metric suggests that a parallel application's sensitivity to network performance variation can be quantified relative to its behaviour in optimal network performance conditions. Ideas on how this metric can be useful to parallel application development, cluster system performance management and system administration are also presented.
Vibration Confinement via Optimal Eigenvector Assignment and Piezoelectric Networks

The underlying principle for vibration confinement is to alter the structural vibration modes so that the corresponding modal components have much smaller amplitude in concerned area than in the remaining part of the structure. In this research, the state-of-the-art in vibration confinement technique is advanced in two correlated ways. First, a new eigenstructure assignment algorithm is developed to more directly suppress vibration in regions of interest. This algorithm is featured by the optimal selection of achievable eigenvectors that minimizes the eigenvector components at concerned region by using the Rayleigh Principle. Second, the active control input is applied through an active-passive hybrid piezoelectric network. With the introduction of circuitry elements, which are much easier to implement than changing or adding mechanical components, the state matrices can be reformed and the design space for eigenstructure assignment can be greatly enlarged. To maximize the system performance, a simultaneous optimization/optimal eigenvector assignment approach to decide the passive and active parameters concurrently is outlined. The merits of the proposed system and scheme are demonstrated and analyzed using numerical examples.
Aerodynamic Study of a Turbine Designed for a Small Low-Cost Turbofan Engine

A 20.32 centimeter (8.00 in.) mean diameter two-stage turbine was experimentally investigated over a range of speeds from 0 to 110 percent of equivalent design speed and over a range of pressure ratios from 2.2 to 4.2. The principal results indicated that the performance level was substantially higher than that assumed in the design. As part of the program to reduce manufacturing costs, the first stage blading was reduced in thickness for ease in coining. Tests of the modified blades indicated that the aerodynamic performance of a stator or rotor blade with a large amount of reaction was affected very little by a significant change of the pressure surface.Copyright © 1973 by ASME
N = 1 superstring in 2 + 2 dimensions

Abstract In this paper we construct a (2,2) dimensional string theory with manifest N = 1 spacetime supersymmetry. We use Berkovits' approach of augmenting the spacetime supercoordinates by the conjugate momenta for the fermionic variables. The worldsheet symmetry algebra is a twisted and truncated “small” N = 4 superconformal algebra. The realisation of the symmetry algebra is reducible with an infinite order of reducibility. We study the physical states of the theory by two different methods. In one of them, we identify a subset of irreducible constraints, which is by itself critical. We construct the BRST operator for the irreducible constraints, and study the cohomology and interactions. This method breaks the SO(2,2) spacetime symmetry of the original reducible theory. In another approach, we study the theory in a fully covariant manner, which involves the introduction of infinitely many ghosts for ghosts.
Longevity and Highest-Energy Cosmic Rays

It is proposed that the highest energy ~1020eV cosmic ray primaries are protons which are decay products of a superheavy particle, G. The protons may be decay products either directly of a nearby (galactic) Gor of a long-lived intermediate particle X which arises from decay of a distant (cosmological) G, then decays in or near our Galaxy. Such scenarios can occur in e.g. SU(15) grand unification and in some preon models.
Maximizing large drive availability

Drive-system availability is a function of both the reliability and repair time of the drive, motor and associated equipment. This is true at the system level, as well as at the component and subcomponent level. To achieve high availability, the reliability of each component as well as the drive itself must be reviewed. Various design methods can be used to improve reliability, such as modeling, component de-rating and margins, component redundancy, component qualification testing, and system qualification testing. Although a good design minimizes the need for repair, the possibility of repair still exists and must be planned for in the design. The repair of large drives can be more complicated than that of smaller drives since it is not economical to replace a complete unit. For this reason, it is necessary to utilize computer-based automated troubleshooting programs in the drive diagnostics design in order to quickly and accurately identify a problem module. The equipment must then be designed to allow rapid replacement of that module. Design, along with a number of other support factors that are covered in this article, will lead to high availability.
Chemical probes of metal cluster structure - Fe, Co, Ni and Cu

Chemical reactivity is one of the few methods currently available for investigating the geometrical structure of isolated transition metal clusters. In this paper we summarize what is currently known about the structures of clusters of four transition metals, Fe, Co, Ni, and Cu, in the size range from 13 to 180 atoms. Chemical probes used to determine structural information include reactions with H2 (D2), H2O, NH3 and N2. Measurements at both low coverage and at saturation are discussed.
A High-Performance Integrated Microwave Circuit Frequency Quadruple

An S- to X-band frequency quadrupler was developed with a 4.0-dB conversion loss and 11-percent bandwidth using hybrid integrated microwave circuit techniques. The multiplier has a low-pass transforming filter on the input and a bandpass filter consisting of half-wavelength lines edge coupled over quarter wavelengths on the output. Design curves for the bandpass filter are given for ceramic microstrip. Two beam-lead varactors were used in the multiplier giving it an input power-handling capability of 3-watts peak power.
Frequency invariant interferometry

The authors discuss frequency-independent phase comparison interferometry as a method of direction finding. Theoretical relationships are derived that show the electrical phase between two elements of an array can remain approximately constant over frequency. The theory is developed for log-periodic dipole arrays. Design and fabrication of a two-element interferometer using log-periodic antennas are discussed. Experimental results are presented which show that this array remains frequency independent over a three-octave bandwidth. >
Nearly optimal algorithms and bounds for multilayer channel routing

This paper presents algorithms for routing channels with L≥2 layers. For the unit vertical overlap model, we describe a two-layer channel routing algorithm that uses at most d + O(√d) tracks to route two-terminal net problems and 2d + O(√d) tracks to route multiterminal nets. We also show that d + Ω(log d) tracks are required to route two-terminal net problems in the worst case even if arbitrary vertical overlap is allowed. We generalize the algorithm to unrestricted multilayer routing and use only d/(L -1) + O(√d/L + 1)> tracks for two-terminal net problems (within O(√d/L + 1) tracks of optimal) and d/(L-2) +O(√d/L + 1) tracks for multiterminal net problems (within a factor of(L-1)/(L-2) times optimal). We demonstrate the generality of our routing strategy by showing that it can be used to duplicate some of the best previous upper bounds for other models (two-layer Manhattan routing and two and three-layer knock-knee routing of two-terminal, two-sided nets), and gives a new upper bound for rotuing with 45-degree diagonal wires.
Flash on disk for low-power multimedia computing

Mobile multimedia computers require large amounts of data storage, yet must consume low power in order to prolong battery life. Solid-state storage offers low power consumption, but its capacity is an order of magnitude smaller than the hard disks needed for high-resolution photos and digital video. In order to create a device with the space of a hard drive, yet the low power consumption of solid-state storage, hardware manufacturers have proposed using flash memory as a write buffer on mobile systems. This paper evaluates the power savings of such an approach and also considers other possible flash allocation algorithms, using both hardware- and software-level flash management. Its contributions also include a set of typical multimedia-rich workloads for mobile systems and power models based upon current disk and flash technology. Based on these workloads, we demonstrate an average power savings of 267 mW (53% of disk power) using hardware-only approaches. Next, we propose another algorithm, termed Energy-efficient Virtual Storage using Application-Level Framing (EVS-ALF), which uses both hardware and software for power management. By collecting information from the applications and using this metadata to perform intelligent flash allocation and prefetching, EVS-ALF achieves an average power savings of 307 mW (61%), another 8% improvement over hardware-only techniques.
Generalized uncertainty relations: Theory, examples, and Lorentz invariance

The quantum-mechanical framework in which observables are associated with Hermitian operators is too narrow to discuss measurements of such important physical quantities as elapsed time or harmonic-oscillator phase. We introduce a broader framework that allows us to derive quantum-mechanical limits on the precision to which a parameter - e.g., elapsed time - may be determined via arbitrary data analysis of arbitrary measurements on N identically prepared quantum systems. The limits are expressed as generalized Mandelstam-Tamm uncertainty relations, which involve the operator that generates displacements of the parameter - e.g., the Hamiltonian operator in the case of elapsed time. This approach avoids entirely the problem of associating a Hermitian operator with the parameter. We illustrate the general formalism, first, with nonrelativistic uncertainty relations for spatial displacement and momentum, harmonic-oscillator phase and number of quanta, and time and energy and, second, with Lorentz-invariant uncertainty relations involving the displacement and Lorentz-rotation parameters of the Poincare group.
Speech analysis and synthesis on a personal computer

A personal computer based system which can be used for speech digitization and acquisition, editing and segmentation, analysis and encoding, synthesis and replay and the study of language phonetic properties is described.The system is user interactive and can be used either in a stand-alone mode to provide all the functions needed for constructive synthesis and synthesis-by-analysis or linked to a host computer to provide additional signal processing capabilities which are useful in speech research.
Nuclear rotational bands and SL(3, R) symmetry

Abstract Nuclear rotational motion is studied under the assumption that the transition E2 operators generate the algebraic symmetry SL(3, R), as first suggested by Gell-Mann, Ne'eman and Dothan. Besides the K = 0+ and K = 0− bands, more general multiband representations are derived. This model predicts ratios of interband transitions in rotational nuclei having no adjustable parameters. These predictions are compared to all available data and show that the model is a semi-quantitative improvement on the rigid-rotator model.
Stabilization of chaotic and non-permanent food-web dynamics

Several decades of dynamical analyses of food-web networks (1-6) have led to important insights into the effects of complexity, omnivory and interaction strength on food-web stability (6-8). Several re- cent insights (7, 8) are based on nonlinear bioenergetic consumer-resource models (9) that display chaotic behavior in three species food chains (10, 11) which can be stabilized by omnivory (7) and weak interaction of a fourth species (8). We slightly relax feeding on low-density prey in these models by modifying stan- dard food-web interactions known as "type II" functional responses (12). This change drastically alters the dynamics of realistic systems containing up to ten species. Our modification stabilizes chaotic dynamics in three species systems and reduces or eliminates extinctions and non-persistent chaos (11) in ten species systems. This increased stability allows analysis of systems with greater biodiversity than in earlier work and suggests that dynamic stability is not as severe a constraint on the structure of large food webs as previously thought. The sensitivity of dynamical models to small changes in the predator-prey functional response well within the range of what is empirically observed suggests that functional response is a crucial aspect of species interactions that must be more precisely addressed in empirical studies.
Geometric deformable colon model for polyp detection

Virtual Colonoscopy is a minimally invasive procedure to detect polyps in the colon using three dimensional tomographic imaging. An important step in analyzing the image data is accurate localization of the lumen surface. Polyps protruding into the colon lumen can then be identified by analyzing the surface either manually or using computer assisted techniques. We have developed a method for lumen segmentation based on a 3D geometric deformable model (GDM) to provide an improved representation of the lumen surface. The results show the GDM can remove the surface holes or tunnels that can be created with thresholding techniques and demonstrates the ability to accurately locate the lumen surface in high contrast air- tissue boundaries while preserving relatively lower contrast boundaries of the houstra and polyps.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Cyclic alkenyl boronic half acid synthesis and applications.

The synthesis of cyclic alkenyl boronic half acids from vinyl and propenyl boronic esters and homoallylic alcohols by ring-closing metathesis is reported. The method is compatible with both conventional and microwave heating and comparable yields are obtained under both conditions. The cyclic alkenyl boronic acids participate in Suzuki−Miyaura coupling reactions in good yields.
THE STABILITY OF TIDALLY DEFORMED NEUTRON STARS TO THREE- AND FOUR-MODE COUPLING

It has recently been suggested that the tidal deformation of a neutron star excites daughter p- and g-modes to large amplitudes via a quasi-static instability. This would remove energy from the tidal bulge, resulting in dissipation and possibly affecting the phase evolution of inspiralling binary neutron stars and hence the extraction of binary parameters from gravitational wave observations. This instability appears to arise because of a large three-mode interaction among the tidal mode and high-order p- and g-modes of similar radial wavenumber. We show that additional four-mode interactions enter into the analysis at the same order as the three-mode terms previously considered. We compute these four-mode couplings by finding a volume-preserving coordinate transformation that relates the energy of a tidally deformed star to that of a radially perturbed spherical star. Using this method, we relate the four-mode coupling to three-mode couplings and show that there is a near-exact cancellation between the destabilizing effect of the three-mode interactions and the stabilizing effect of the four-mode interaction. We then show that the equilibrium tide is stable against the quasi-static decay into daughter p- and g-modes to leading order. The leading deviation from the quasi-static approximation due to orbital motion of the binary is considered; while it may slightly spoil the near-cancellation, any resulting instability timescale is at least of order the gravitational wave inspiral time. We conclude that the p-/g-mode coupling does not lead to a quasi-static instability, and does not impact the phase evolution of gravitational waves from binary neutron stars.
Optimal sizing, loading and re-loading in a multi-level memory hierarchy system

Starting with the appearance of the third generation computers the demand for memory storage devices has increased. This increased demand has been for both the main storage and auxiliary storage devices. The major reasons for this increase were the problems of larger data processing tasks and the introduction of multiprogramming and time-sharing.
Recognizing superpartners at LEP

There is class of supersymmetric models which is well-motivated by hints of evidence for SUSY and consistent with all existing data. It is important to study the predictions of these models. They are characterized by MN3 ≳ MC1 > Mν > MN1 (where Ni and Ci are neutralino and chargino mass eigenstates), |μ| ≲ M1 ≲ M2 ≈ Mz, μ < 0, and tan β near 1. Their LEP signatures are mostly unusual. Most produced superpartners are invisible! A good signature is two photons plus large missing energy. There are also excess events at large recoil mass in the single photon plus nothing channel. We list the main signatures for charginos, stops, etc., which are also likely to be unconventional. This class of models will be definitively tested at LEP194 with 100 pb−1 per detector, and almost definitively tested at LEP184.
A Method of Correcting Near‐Infrared Spectra for Telluric Absorption*

We present a method for correcting near-infrared medium-resolution spectra for telluric absorption. The method makes use of a spectrum of an A0 V star, observed near in time and close in air mass to the target object, and a high-resolution model of Vega, to construct a telluric correction spectrum that is free of stellar absorption features. The technique was designed specifically to perform telluric corrections on spectra obtained with SpeX, a 0.8-5.5 mm medium-resolution cross-dispersed spectrograph at the NASA Infrared Telescope Facility, and uses the fact that for medium resolutions there exist spectral regions uncontaminated by atmospheric absorption lines. However, it is also applicable (in a somewhat modified form) to spectra obtained with other near-infrared spectrographs. An IDL-based code that carries out the procedures is available for downloading via the World Wide Web.
Phase-nonlinearity interplay in small quantum systems

Abstract We report effects of the interplay of quantum phases and nonlinearity in small quantum systems that are characterized by strong interactions between a quasiparticle (an excitation or an electron) and lattice vibrations, and are described by the discrete nonlinear Schrodinger equation. The issue under investigation is the influence that features of the initial placement of a quasiparticle can have on the process of self-trapping. We find that initial phases profoundly control the dependence of self-trapping on initial inhomogeneity. We also find that the only non-trivial stationary state of the system disappears in the presence of complex initial site amplitudes and that the amplitude of oscillations, which dips sharply to zero at the stationary state for real initial amplitudes, approaches a nonzero minimum for complex initial amplitudes.
Nutritional gatekeepers and the 72% solution.

More than ever, we make food choices in distracting, media filled, food-rich environments. It is not surprising that some clients — even some registered dietitians — become fatalistic about the limited influence they believe they have over the nutrition of their family. They come to believe that they have little power when competing against incessant advertising and easily available, inexpensive, tempting foods. As food and nutrition professionals, it is difficult to encourage or empower a fatalistic person to provide better nutrition for their family. It can even lead us to be pessimistic, “How can we possibly empower anybody when we are overworked, overstressed, and over budget?” While new data suggest some new answers, the question has deep roots. It begins with an insight from a famous anthropologist. Margaret Mead first hinted at it over 60 years ago — in 1945 — here in the Journal of the American Dietetic Association.
Stefan-Maxwell mass transport

Abstract Stefan–Maxwell multicomponent transport equations have a lot of appeal because of their symmetry and because the diffusion coefficients are independent of composition for ideal gases. A simple numerical solution method, which can easily be extended to more components, is illustrated for the popular chemical-engineering film, penetration, and boundary-layer models with a particular example of evaporation of acetone and methanol through air. Extension of each model to other geometries and chemical systems is discussed. In the boundary-layer model there is no need to assume that both total concentration and density are constant.
Quantization of Equivariant Vector Bundles

The quantization of vector bundles is defined. Examples are constructed for the well controlled case of equivariant vector bundles over compact coadjoint orbits. (A coadjoint orbit is a symplectic manifold with a transitive, semisimple symmetry group.) In preparation for the main result, the quantization of coadjoint orbits is discussed in detail. This subject should not be confused with the quantization of the total space of a vector bundle such as the cotangent bundle.
Vacuum expectation values of products of chiral currents in 3+1 dimensions

An algebraic rule is presented for computing expectation values of products of local nonabelian charge operators for fermions coupled to an external vector potential in 3+1 space-time dimensions. The vacuum expectation value of a product of four operators is closely related to a cyclic cocycle in noncommutative geometry of Alain Connes. The relevant representation of the current is constructed using Kirillov's method of coadjoint orbits.
Type I Planetary Migration with MHD Turbulence

This paper examines how type I planetary migration is affected by the presence of turbulent density fluctuations in the circumstellar disk. For type I migration, the planet does not clear a gap in the disk and its secular motion is driven by torques generated by the wakes it creates in the surrounding disk fluid. MHD turbulence creates additional density perturbations that gravitationally interact with the planet and can dominate the torques that stem from the protoplanetary wake. This paper shows that conventional type I migration can be readily overwhelmed by turbulent perturbations, and hence the usual description of type I migration should be modified in locations where the magnetorotational instability is active. In general, the migrating planet does not follow a smooth inward trend but rather exhibits a random walk through phase space. Our main conclusion is that MHD turbulence will alter the timescales for type I planetary migration and, because of chaos, requires the timescales to be described by a distribution of values.
Evidence for in Situ Catalyst Modification during the Pd-Catalyzed Conversion of Aryl Triflates to Aryl Fluorides

A mechanistic investigation of the Pd-catalyzed conversion of aryl triflates to fluorides is presented. Studies reveal that C-F reductive elimination from a LPd(II)(aryl)F complex (L = t-BuBrettPhos or RockPhos) does not occur when the aryl group is electron rich. Evidence is presented that a modified phosphine, generated in situ, serves as the actual supporting ligand during catalysis with such substrates. A preliminary study of the reactivity of a LPd(II)(aryl)F complex based on this modified ligand is reported.
Improved accuracy tristimulus colorimeters calibrated with standard detectors

A new method has been developed to calibrate tristimulus colorimeters for high accuracy color measurements. Instead of traditional lamp standards, modern, high accuracy detector standards are suggested for calibration. After high accuracy absolute spectral response determination of the tristimulus receivers, color (spectral) correction and peak (amplitude) normalization can minimize uncertainties caused by imperfect realizations of the Commission Internationale de l'Eclairage color matching functions. As a result of the corrections, stable light sources of different spectral power distributions can be measured with an accuracy dominated by the sub 0.1% uncertainty of novel spectral response determinations.
FREE VIBRATION OF COUPLED DISK–HAT STRUCTURES

Abstract The free vibration of disk–hat structures, such as automotive brake rotors, is investigated analytically and through laboratory experimentation. Of particular interest are the role played by the hat element's depth in influencing the three-dimensional vibration of the disk, and the manner in which the bending and in-plane modes of the disk alone evolve as a hat of increasing depth is incorporated in the model. The lower vibration modes of disk–hat structures are shown to be characterized by the numbers of nodal circles NC and diameters ND present on the disk, as well as the phase relationship between the disk's transverse and radial displacements due to coupling with the hat element. Such modes map continuously back to the pure bending and in-plane modes of the disk alone, appear in ordered pairs, and can exist at close frequencies. Those characteristics are explored particularly with respect to sensitivities in the disk's thickness and the hat's depth with a view towards shifting particular natural frequencies, or minimizing transverse disk motion in certain vibration modes. Results obtained through analysis and measurement of a prototypical disk–hat structure are applied in a case study with a ventilated automotive brake rotor.
Lost on the web: Does web distribution stimulate or depress television viewing?

Abstract In the past few years, YouTube and other sites for sharing video files over the Internet have vaulted from obscurity to places of centrality in the media landscape. The files available at YouTube include a mix of user-generated video and clips from network television shows. Networks fear that availability of their clips on YouTube will depress television viewing. But unauthorized clips are also free advertising for television shows. As YouTube has grown quickly, major networks have responded by making their content available at their own sites. This paper examines the effects of authorized and unauthorized web distribution on television viewing between 2005 and 2007 using a survey of Penn students on their tendencies to watch television series on television as well as on the web. The results provide a glimpse of the way young, Internet-connected people use YouTube and related sites. While I find some evidence of substitution of web viewing for conventional television viewing, time spent on viewing programming on the web – 6.8 h per week – far exceeds the reduction in weekly traditional television viewing of about 7 min. Perhaps more important, overall time spent on network-controlled viewing (television plus network web sites) increased by 3.7 h per week.
Hysteresis in Hard Superconductors

To incorporate the effects of pinning due to defects and predict size- dependence and hysteresis in the magnetization curves of hard superconductors, the AbrikosovCoodman theory is developed. The interaction forces between fluxoid filaments are determined semiempirically. The method developed is illustrated by application to a simple case. (C.E.S.)
Using wavelets to obtain a consistent ordinary least squares estimator of the long-memory parameter

We develop an ordinary least squares estimator of the long memory parameter from a fractionally integrated process that is an alternative to the Geweke Porter-Hudak estimator. Using the wavelet transform from a fractionally integrated process, we establish a log-linear relationship between the wavelet coefficients' variance and the scaling parameter equal to the long memory parameter. This log-linear relationship yields a consistent ordinary least squares estimator of the long memory parameter when the wavelet coefficients' population varinace is replaced by their sample variance. We derive the small sample bias and variance of the ordinary least squares estimator and test it against the Geweke Porter-Hudak estimator and the McCoy Walden maximum likelihood wavelet estimator by conducting a number of Monte Carlo experiments. Based upon the criterion of choosing the estimator which minimizes the mean squared error, the wavelet OLS approach was superior to the Geweke Porter-Hudak estimator, but inferior to the McCoy Walden wavelet estimator for the processes simulated. However, given the simplicity of programming and running the wavelet OLS estimator and its statistical inference of the long memory parameter we feel the general practitioner will be attracted to the wavelet OLS estimator.
Absolutely continuous spectrum of Stark operators

We prove several new results on the absolutely continuous spectra of perturbed one-dimensional Stark operators. First, we find new classes of perturbations, characterized mainly by smoothness conditions, which preserve purely absolutely continuous spectrum. Then we establish stability of the absolutely continuous spectrum in more general situations, where imbedded singular spectrum may occur. We present two kinds of optimal conditions for the stability of absolutely continuous spectrum: decay and smoothness. In the decay direction, we show that a sufficient (in the power scale) condition is |q(x)|≤C(1+|x|)−1/4−e; in the smoothness direction, a sufficient condition in Holder classes isq∈C 1/2+e(R). On the other hand, we show that there exist potentials which both satisfy |q(x)|≤C(1+|x|)−1/4 and belong toC 1/2(R) for which the spectrum becomes purely singular on the whole real axis, so that the above results are optimal within the scales considered.
Response to Home or Office Blood Pressure Monitoring in Predicting Cardiovascular Events: What is Policy Implication?

We appreciate the comments made by Shiue1 concerning our article and also healthcare policy in general. We do not feel that the times of measurement for home and office blood pressure (BP) used in our study are a limitation because they are similar …
Atlas of reflectance spectra of terrestrial, lunar, and meteoritic powders and frosts from 92 to 1800 nm

The spectra of samples of several powder and frost materials are presented to serve in a reference database for future far-UV scans of solar system bodies. The spectra cover in the 92-1800 nm wavelengths, i.e., wavenumbers 110,000-5600/cm and photon energies from 13.5-1.5 eV. Preparation procedures for the particulates are delineated. The survey includes feldspars, orthopyroxenes, clinopyroxenes, olivines, assorted minerals, achondrites, carbonaceous chondrites and ordinary chondrites, lunar soils and rocks. Frosts of H2O, CO2, NH3 and SO2 gases were also examined. The data are expected to aid in obtaining spectral matches for asteroids and meteoroids when far-UV telescopy of solar system bodies is performed.
Cycloaddition of isoquinolinium salts: homochiral tetralins via dienophiles bearing chiral auxiliaries

Abstract Inverse electron demand cycloaddition of isoquinolinium salts to dienophiles bearing chiral auxiliaries to produce homochiral tetralins are described. The optical purity of the product ranges from 5% to 95+% depending on the nature of the chiral auxiliary.
A singular loop transformation framework based on non-singular matrices

In this paper, we discuss a loop transformation framework that is based on integer non-singular matrices. The transformations included in this framework are called Λ-transformations and include permutation, skewing and reversal, as well as a transformation calledloop scaling. This framework is more general than existing ones; however, it is also more difficult to generate code in our framework. This paper shows how integer lattice theory can be used to generate efficient code. An added advantage of our framework over existing ones is that there is a simple completion algorithm which, given a partial transformation matrix, produces a full transformation matrix that satisfies all dependences. This completion procedure has applications in parallelization and in the generation of code for NUMA machines.
Tree Diagrams for String Links

In previous work, the author defined the intersection graph of a chord diagram associated with a string link (as in the theory of finite type invariants). In this paper, we classify the trees which can be obtained as intersection graphs of string link diagrams.
Pediatric Disorders of Water Balance

Fluid homeostasis requires adequate water intake, regulated by an intact thirst mechanism and appropriate free water excretion by the kidneys, mediated by appropriate secretion of arginine vasopressin (AVP, also known as antidiuretic hormone). AVP exerts its antidiuretic action by binding to the X chromosome-encoded V2 vasopressin receptor (V2R), a G protein coupled receptor on the basolateral membrane of renal collecting duct epithelial cells. After V2R activation, increased intracellular cyclic adenosine monophosphate mediates shuttling of the water channel aquaporin 2 to the apical membrane of collecting duct cells, resulting in increased water permeability and antidiuresis. Clinical disorders of water balance are common, and abnormalities in many steps involving AVP secretion and responsiveness have been described. This article focuses on the principal disorders of water balance, diabetes insipidus, and the syndrome of inappropriate antidiuretic hormone secretion.
On the Early-Time X-Ray Spectra of Swift Afterglows. I. Evidence for Anomalous Soft X-Ray Emission

We have conducted a thorough and blind search for emission lines in >70 Swift X-ray afterglows of total exposure ~107 s. We find that most afterglows are consistent with pure power laws plus extinction. Significant outliers to the population exist at the 5%-10% level and have anomalously soft, possibly thermal spectra. Four bursts are singled out via possible detections of two to five lines: GRB 060218, GRB 060202, GRB 050822, and GRB 050714B. Alternatively, a blackbody model with kT ~ 0.1-0.5 keV can describe the soft emission in each afterglow. The most significant soft-component detections in the full data set of ~2000 spectra correspond to GRB 060218/SN 2006aj, with line significances ranging up to ~20 ?. A thermal plasma model fit to the data indicates that the flux is primarily due to L-shell transitions of Fe at roughly solar abundance. We associate (>4 ? significant) line triggers in the three other events with K-shell transitions in light metals. We favor a model where the possible line emission in these afterglows arises from the mildly relativistic cocoon of matter surrounding the GRB jet as it penetrates and exits the surface of the progenitor star. The emitting material in each burst is at a similar distance ~1012-1013 cm, a similar density ~1017 cm-3, and subject to a similar flux of ionizing radiation. The lines may correlate with the X-ray flaring. For the blackbody interpretation, the soft flux may arise from breakout of the GRB shock or plasma cocoon from the progenitor stellar wind, as recently suggested for GRB 060218 (Campana et al. 2006). Due to the low z of GRB 060218, bursts faint in gamma rays with fluxes dominated by this soft X-ray component could outnumber classical GRBs 100 to 1.
Identification of exotic jet topologies via three-particle correlations in PHENIX

Modifications of jet properties resulting from the coupling of jets to the strongly interacting matter produced in RHIC collisions are of great current interest. In recent work, the PHENIX collaboration has applied a novel technique to the analysis of two-particle azimuthal correlations which extinguishes the harmonic part of the underlying event revealing the true jet shape. Recent extensions of the method to three-particle correlations allow for a more revealing study of jet topologies in Au+Au collisions at (√s NN=200 GeV).
PAC learning intersections of halfspaces with membership queries

A randomized learning algorithm {POLLY} is presented that efficiently learns intersections of s halfspaces in n dimensions, in time polynomial in both s and n . The learning protocol is the PAC (probably approximately correct) model of Valiant, augmented with membership queries. In particular, {POLLY} receives a set S of m = poly(n,s,1/e,1/δ) randomly generated points from an arbitrary distribution over the unit hypercube, and is told exactly which points are contained in, and which points are not contained in, the convex polyhedron P defined by the halfspaces. {POLLY} may also obtain the same information about points of its own choosing. It is shown that after poly(n , s , 1/e , 1/δ , log(1/d) ) time, the probability that {POLLY} fails to output a collection of s halfspaces with classification error at most e , is at most δ . Here, d is the minimum distance between the boundary of the target and those examples in S that are not lying on the boundary. The parameter log(1/d) can be bounded by the number of bits needed to encode the coefficients of the bounding hyperplanes and the coordinates of the sampled examples S . Moreover, {POLLY} can be extended to learn unions of k disjoint polyhedra with each polyhedron having at most s facets, in time poly(n , k , s , 1/e , 1/δ , log(1/d) , 1/γ ) where γ is the minimum distance between any two distinct polyhedra.
On the stability of asynchronous iterative processes

We consider an iterative process in which one out of a finite set of possible operators is applied at each iteration. We obtain necessary and sufficient conditions for convergence to a common fixed point of these operators, when the order at which different operators are applied is left completely free, except for the requirement that each operator is applied infinitely many times. The theory developed is similar in spirit to Lyapunov stability theory. We also derive some very different, qualitatively, results for partially asynchronous iterative processes, that is, for the case where certain constraints are imposed on the order at which the different operators are applied.
Electrically Controlled Modulation in a Photonic Crystal Nanocavity

We describe a compact modulator based on a photonic crystal nanocavity whose resonance is electrically controlled through an integrated p-i-n junction. The sub-micron size of the nanocavity promises very low capacitance, high bandwidth, and efficient on-chip integration in optical interconnects.