cssi/SciSciGPT-SciSciNet huggingface dataset:
Surface versus internal loading of the Tharsis rise, Mars

[1] Two hypotheses compete to explain the remarkable topography and geoid of the Tharsis province on Mars: One attributes Tharsis to volcanically constructed surface loads, whereas the second views it as dynamic effects of single-plume mantle convection. Both are likely to contribute, so we would like to constrain both. We introduce a method to invert load structure from geoid and topography of a viscoelastic planetary body. Estimates of the internal load contribution to Tharsis depend on assumed parameters. Buoyancy of the internal load estimate increases with increasing lithospheric thickness, crustal density, and crustal thickness, and load size increases with depth of loading. Despite parameter uncertainties, we can rule out a predominantly internal load. We cannot reject the possibility that Tharsis results from surface loading alone. Internal loads contribute at most 35% of the lithospheric force balance, 50% of the topography, and 25% of the geoid at Tharsis, for load depths ≤420 km and lithospheric thickness Te ≤ 200 km. A corollary is that any Te and reference density structure can exactly reproduce the geoid and topography if internal loading can vary as a function of harmonic degree and order. Hence Te and density estimates depend on assumptions about internal loading. If surface and internal loads are approximately uncorrelated, Te is ∼110 km with crustal density ∼2600 kg m−3. Adopting these parameters, internal buoyancy contributes 2.1% of lithospheric loading, 4.2% of topography, and 0.7% of the geoid at Tharsis for a 200 km deep load, or 4.3% of lithospheric loading, 8.5% of topography, and 2.2% of the geoid for a load at 400 km depth.
Weak and strong solutions of general stochastic models

Typically, a stochastic model relates stochastic “inputs” and, perhaps, controls tostochastic “outputs”. A general version of the Yamada-Watanabe and Engelbert the-orems relating existence and uniqueness of weak and strong solutions of stochasticequations is given in this context. A notion of compatibility between inputs and out-puts is critical in relating the general result to its classical forebears. The usualformulation of stochastic differential equations driven by semimartingales does notrequire compatibility, so a notion of partial compatibility is introduced which doeshold. Since compatibility implies partial compatibility, classical strong uniquenessresults imply strong uniqueness for compatible solutions. Weak existence argumentstypically give existence of compatible solutions (not just partially compatible solu-tions), and as in the original Yamada-Watanabe theorem, existence of strong solutionsfollows.
Diffractive hard scattering with a coherent pomeron

Abstract Diffractive scattering involves exchange of a pomeron to make a rapidity gap. It is normally assumed that to get a hard scattering in diffraction, one may treat the pomeron as an ordinary particle, which has distributions of gluons and quarks. We show that this is not so: When we use perturbative QCD, there is a breakdown of the factorization theorem. The whole pomeron can initiate the hard scattering, even though it is not point-like. Qualitatively, but not quantitatively, this gives the same effect as a delta-function term in the gluon density in a pomeron.
Multichannel generalization of Kitaev's Majorana end states and a practical route to realize them in thin films.

The ends of one-dimensional $p+ip$ superconductors have long been predicted to possess localized Majorana fermion modes [A. Kitaev, arXiv:cond-mat/0010440]. We show that Majorana end states are robust beyond the strict 1D single-channel limit, so long as the sample width is not much larger than the superconducting coherence length, and they exist when an odd number of transverse quantization channels are occupied. Consequently, the system undergoes a sequence of topological phase transitions driven by changing the chemical potential. These observations make it feasible to implement quasi-1D $p+ip$ superconductors in metallic thin-film microstructures, which offer 3--4 orders of magnitude larger energy scales than semiconductor-based schemes. Some promising candidate materials are described.
Women Empowerment and Economic Development

Women empowerment and economic development are closely related: in one direction, development alone can play a major role in driving down inequality between men and women; in the other direction, empowering women may benefit development. Does this imply that pushing just one of these two levers would set a virtuous circle in motion? This paper reviews the literature on both sides of the empowerment– development nexus, and argues that the interrelationships are probably too weak to be self-sustaining, and that continuous policy commitment to equality for its own sake may be needed to bring about equality between men and women.
Combinatorics and geometry of power ideals

We investigate ideals in a polynomial ring which are generated by powers of linear forms. Such ideals are closely related to the theories of fat point ideals, Cox rings, and box splines. We pay special attention to a family of power ideals that arises naturally from a hyperplane arrangement A. We prove that their Hilbert series are determined by the combinatorics of A and can be computed from its Tutte polynomial. We also obtain formulas for the Hilbert series of certain closely related fat point ideals and zonotopal Cox rings. Our work unifies and generalizes results due to Dahmen-Micchelli, Holtz-Ron, Postnikov-Shapiro-Shapiro, and Sturmfels-Xu, among others. It also settles a conjecture of Holtz-Ron on the spline interpolation of functions on the lattice points of a zonotope.
Direct Current Ground Electrode Behavior

The conducting of moderately high direct current through earth between variously sized electrodes installed in different types of soil has provided test data which, while in general agreement with expectations [1]-[3], places much more emphasis on the electrode-to-earth contact area than had been necessary in past designs, which were primarily used for conducting ground currents of short time duration. Analysis of the data indicates that the design of a grounding grid which is to carry current to earth continuously for several hours can be treated as two independent problems: The outer dimensions, or perimeter, should be based upon computed resistance to remote earth [4], with utilization of the low-resistivity valuesg usually measured at wide probe spacings. The contact area should be based upon the power dissipation value computed from the square of the proposed current density and from the measured soil-resistivity value at the electrode-to-soil interface.
Airfoil tip vortex formation noise

Spectral data are presented for the noise produced due to the turbulent three-dimensional vortex flow existing near the rounded tip of lifting airfoils. The results are obtained by the comparison of sets of two- and three-dimensional test data for different airfoil model sizes, angles of attack, and tunnel flow velocities. Microphone cross-correlation and cross-spectral methods were used to determine the radiated noise. Corrections were made for tunnel shear layer and source directivity effects. Interpretation of the results are aided by a three-dimensional flow analysis developed for this study which determines open tunnel and finite aspect ratio corrections heretofore neglected in tip vortex studies. Hot wire measurements were made in the tip vortex formation region for the specification of governing flow parameters. The spectral data is normalized in a format considered most useful for subsequent quantitative prediction of this noise mechanism for practical systems such as helicopter rotors. Comparison is made to the analysis of George and Chou. A recommended prediction method is given.
Marital History, Race, and Social Security Spouse and Widow Benefit Eligibility in the United States:

Large-scale changes in American family structures over the past decades have important implications for the retirement experiences of women. In this study, the authors use a restricted-use file of ...
Analysis of general aviation accidents using ATC radar records

It is pointed out that general aviation aircraft usually do not carry flight recorders, and in accident investigations the only available data may come from the Air Traffic Control (ATC) records. A description is presented of a technique for deriving time-histories of aircraft motions from ATC radar records. The employed procedure involves a smoothing of the raw radar data. The smoothed results, in combination with other available information (meteorological data and aircraft aerodynamic data) are used to derive the expanded set of motion time-histories. Applications of the considered analytical methods are related to different types of aircraft, such as light piston-props, executive jets, and commuter turboprops, as well as different accident situations, such as takeoff, climb-out, icing, and deep stall.
MR Imaging of Primary Bone Tumors and Tumor-like Conditions in Children

This article provides a review of the MR imaging features of the major primary malignant and benign bone tumors and tumorlike conditions encountered in the pediatric population. Malignant tumors discussed include osteosarcoma, Ewing sarcoma, chondrosarcoma, lymphoma, and malignant fibrous histiocytoma. Benign lesions discussed include simple bone cysts, aneurysmal bone cysts, giant cell tumor, osteochondroma, enchondroma, chondroblastoma, osteoid osteoma, osteoblastoma, nonossifying fibroma, fibrous dysplasia, osteofibrous dysplasia, hemangioma, and histiocytosis. The use of MR imaging in the diagnosis of these lesions is discussed, and the text is enhanced with imaging examples of the lesions.
Identifying Old Tidal Dwarf Irregulars

We examine the observational consequences of the two possible origins for irregular galaxies: formation from collapse of a primordial cloud of gas early in the age of the universe, or formation from tidal tails in an interaction that could have occurred any time in the history of the universe. Because the formation from tidal tails could have occurred a long time ago, proximity to larger galaxies is not sufficient to distinguish tidal dwarfs from traditional dwarfs. We consider the effects of little or no dark matter on rotation speeds and the Tully-Fisher relationship, the metallicity-luminosity relationship, structure, and stellar populations. From these selection criteria, we identify a small list of dwarf irregular galaxies that are candidates for having formed as tidal dwarfs.
Localization of light in linear and nonlinear random layered dielectric systems that are periodic on average

Abstract We compute the localization properties of light in a random system of linear dielectric slabs and a random system of Kerr-like nonlinear dielectric slabs. Particular attention is paid to systems that are periodic on average, and studies are made of the localization of light in these systems at frequencies both within and outside the band gaps of the average periodic system. It is found that the average periodic properties have the greatest effect on the exponential localization of light in the linear system, and exhibit only a small transient influence on the power-law localization observed in the nonlinear system. The average periodic properties of the nonlinear system are observed to affect localization only in systems of finite extent.
A first analysis of the stability of Takens' embedding

Takens' Embedding Theorem asserts that when the states of a hidden dynamical system are confined to a low-dimensional attractor, complete information about the states can be preserved in the observed time-series output through the delay coordinate map. However, the conditions for the theorem to hold ignore the effects of noise and time-series analysis in practice requires a careful empirical determination of the sampling time and number of delays resulting in a number of delay coordinates larger than the minimum prescribed by Takens' theorem. In this paper, we use tools and ideas in Compressed Sensing to provide a first theoretical justification for the choice of the number of delays in noisy conditions. In particular, we show that under certain conditions on the dynamical system, linear measurement function, number of delays and sampling time, the delay-coordinate map can be a stable embedding of the dynamical systems attractor.
Scaling Laws for Advection-dominated Flows: Applications to Low-Luminosity Galactic Nuclei

We present analytical scaling laws for self-similar advection-dominated flows. The spectra from these systems range from 108 to 1020 Hz and are determined by considering cooling of electrons through synchrotron, bremsstrahlung, and Compton processes. We show that the spectra can be quite accurately reproduced without detailed numerical calculations and that there is a strong testable correlation between the radio and X-ray fluxes from these systems. We describe how different regions of the spectrum scale with the mass of the accreting black hole, M, the accretion rate of the gas, ${u{M}{"705F}}$ -->, and the equilibrium temperature of the electrons, Te. We show that the universal radio spectral index of 1/3 observed in most elliptical galaxies (Slee et al.) is a natural consequence of self-absorbed synchrotron radiation from these flows. We also give expressions for the total luminosity of these flows and the critical accretion rate, ${u{M}{"705F}}$ -->crit${r crit}$ -->, above which the advection solutions cease to exist. We find that for most cases of interest, the equilibrium electron temperature is fairly insensitive to M, ${u{M}{"705F}}$ -->, and parameters in the model. We apply these results to low-luminosity black holes in galactic nuclei. We show that the problem posed by Fabian & Canizares of whether bright elliptical galaxies host dead quasars is resolved, as pointed out recently by Fabian & Rees, by considering advection-dominated flows.
Measuring organizational performance in the absence of objective measures: The case of the privately-held firm and conglomerate business unit

Strategic management researchers often encounter problems obtaining objective measures of selected aspects of organizational performance that are reliable and valid. With privately-held firms, such data are frequently unavailable. With conglomerate business units, all or parts of such data are inextricably interwoven with corporate-wide data. This paper examines the usefulness of subjective performance measures, obtained from top management teams, when problems are encountered in obtaining accurate performance data.
Surface-wave waveguides

We present simulations and measurements of surface-wave waveguides (SWGs) for guiding surface waves (SWs) along straight and curved paths. In its simplest form, the SWG is a two-dimensional analog to a dielectric waveguide where a low-index material surrounds a high-index material. The most common method for realizing materials with differing SW index is to use a grid of metallic patches of varying size on a dielectric substrate. The phase front of the guided SW can be precisely controlled using a combination of SW-index grading and rotation of the SW-index tensor.
Measures of fine tuning

Abstract Fine-tuning criteria are frequently used to place upper limits on the masses of superpartners in supersymmetric extensions of the standard model. However, commonly used prescriptions for quantifying naturalness have some important shortcomings. Motivated by this, we propose new criteria for quantifying fine tuning that can be used to place upper limits on superpartner masses with greater fidelity. In addition, our analysis attempts to make explicit the assumptions implicit in quantifications of naturalness. We apply our criteria to the minimal supersymmetric extension of the standard model, and we find that the scale of supersymmetry breaking can be larger than previous methods indicate.
Feasibility analysis of controller design for adaptive channel hopping

Communication reliability in Wireless Sensor Networks (WSNs) is challenged by narrow-band interference and persistent multichannel fading. Frequency-agile communication protocols have been recently designed and standardized to increase reliability. These protocols, however, do not adapt the set of channels they hop on to the environment.In this paper, we evaluate the efficiency of a controller which continuously samples all available frequency channels in order to operate on a channel which performs reasonably well. We show that the overall average link Packet Delivery Ratio when using this controller reaches 99.4%, and is higher compared to a single channel solution, on any channel.We evaluate the efficiency of this approach by simulating its behavior on connectivity traces gathered during a real-world deployment. This data set is dense in time and sufficiently large in number of nodes and time to be statistically valid. We believe that the use of connectivity traces for performance evaluation will become commonplace as the number and variety of these traces increases.
Comparisons of plutonium, thorium, and cerium tellurite sulfates.

The hydrothermal reaction of PuCl3 or CeCl3 with TeO2 in the presence of sulfuric acid under the comparable conditions results in the crystallization of Pu(TeO3)(SO4) or Ce2(Te2O5)(SO4)2, respectively. Pu(TeO3)(SO4) and its isotypic compound Th(TeO3)(SO4) are characterized by a neutral layer structure with no interlamellar charge-balancing ions. However, Ce2(Te2O5)(SO4)2 possesses a completely different dense three-dimensional framework. Bond valence calculation and UV–vis–NIR spectra indicate that the Ce compound is trivalent whereas the Pu and Th compounds are tetravalent leading to the formation of significantly different compounds. Pu(TeO3)(SO4), Th(TeO3)(SO4), and Ce2(Te2O5)(SO4)2 represent the first plutonium/thorium/cerium tellurite sulfate compounds. Our study strongly suggests that the chemistries of Pu and Ce are not the same, and this is another example of the failure of Ce as a surrogate.
An Accretion Model for Anomalous X-Ray Pulsars

We present a model for the anomalous X-ray pulsars (AXPs) in which the emission is powered by accretion from a fossil disk, established from matter falling back onto the neutron star following its birth. The time-dependent accretion drives the neutron star toward a ii tracking ˇˇ solution in which the rotation period of the star increases slowly, in tandem with the declining accretion rate. For appropriate choices of disk mass, neutron star magnetic —eld strength, and initial spin period, we demonstrate that a rapidly rotating neutron star can be spun down to periods characteristic of AXPs on timescales compa- rable to the estimated ages of these sources. In other cases, accretion onto the neutron star switches oU after a short time and the star becomes an ordinary radio pulsar. Thus, in our picture, radio pulsars and AXPs are drawn from the same underlying population, in contrast to the situation in models involving neutron stars with ultrastrong magnetic —elds, which require a new population of stars with very diUer- ent properties. Subject headings: accretion, accretion diskspulsars: generalstars: neutronX-rays: stars
The phenomenology of high-temperature superconductive materials.

High-temperature superconductors offer considerable promise for high current applications. Some of the relevant issues, such as materials, grain boundaries and dissipation, will be introduced and both the fundamental and practical aspects will be addressed. For example, the first generation powder-in-tube wires based on the bismuth cuprate have restricted high field performance at liquid nitrogen temperature due to the weak inter-bilayer coupling of magnetic vortices. The second generation coated conductor uses YBa2Cu3O7 to overcome this, but it requires a high degree of biaxial texturing in order to provide notable performance in high fields in liquid nitrogen.
Closing in on a Short-Hard Burst Progenitor: Constraints from Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b

The localization of the short-duration, hard-spectrum gamma-ray burst GRB 050509b by the Swift satellite was a watershed event. We report the discovery of the probable host galaxy, a bright elliptical galaxy atz = 0.2248. This is the first known redshift and host of a short-hard GRB and shows that at least some short-hard GRBs are cosmological in origin. We began imaging the GRB field 8 minutes after the burst and continued for 8 days. We present a reanalysis of the XRT afterglow and report the absolute position of the GRB. Based on positional coincidences, the GRB and the elliptical are likely to be physically related, unlike any known connection between a long-duration GRB and an early-type galaxy. Similarly unique, GRB 050509b likely also originated from within a rich cluster of galaxies with detectable diffuse X-ray emission. We demonstrate that while the burst was underluminous, the ratio of the blast wave energy to the γ-ray energy is consistent with that of long-duration GRBs. Based on this analysis, on the location of the GRB (40 ± 13 kpc from the putative host), on the galaxy type (elliptical), and the lack of a coincident supernova, we suggest that there is now observational support for the hypothesis that short-hard bursts arise during the merger of a compact binary. We limit the properties of any Li-Paczynski "minisupernova" that is predicted to arise on ∼1 day timescales. Other progenitor models are still viable, and new Swift bursts will undoubtedly help to further clarify the progenitor picture. © 2006. The American Astronomical Society. All rights reserved.
Photon detection in the Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN)

The Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN) is being built at Los Alamos National Laboratory. A hexagonal time projection cham- ber (TPC) with a 1 m drift length will be constructed inside a cryostat containing 7,700L of liquid argon. CAPTAIN will be used to test interactions using beams of neutrons and neutrinos. It will serve as a test bed for various options for the Long Baseline Neutrino Experiment (LBNE) includ- ing in the photon detection system. The current photon detection system will be described and future options discussed. The system is composed of sixteen R8520-500 Hamamatsu photomulti- plier tubes with a wavelength shifting coating on acrylic in front of the PMT. Various wavelength shifting coatings can be examined with the current default of tetraphenyl butadiene.
Seventeen dubious methods to approximate the gradient for nonlinear filters with particle flow

We have investigated more than 17 distinct methods to approximate the gradient of the loghomotopy for nonlinear filters. This is a challenging problem because the data are given as function values at random points in high dimensional space. This general problem is important in optimization, financial engineering, quantum chemistry, chemistry, physics and engineering. The best general method that we have developed so far uses a simple idea borrowed from geology combined with a fast approximate k-NN algorithm. Extensive numerical experiments for five classes of problems shows that we get excellent performance.
Eccentricities of Double Neutron Star Binaries

Recent pulsar surveys have increased the number of observed double neutron stars (DNSs) in our galaxy enough so that observable trends in their properties are starting to emerge. In particular, it has been noted that the majority of DNSs have eccentricities less than 0.3, surprisingly low for binaries that survive a supernova explosion, which we believe imparts a significant kick to the neutron star. To investigate this trend, we generate many different theoretical distributions of DNS eccentricities using Monte Carlo population synthesis methods. We determine which eccentricity distributions are most consistent with the observed sample of DNS binaries. In agreement with the work of Chaurasia and Bailes, assuming all DNSs are equally as probable to be discovered as binary pulsars, we find that highly eccentric, coalescing DNSs are less likely to be observed because of their accelerated orbital evolution due to gravitational wave emission and possible early mergers. Based on our results for coalescing DNSs, we also find that models with vanishingly or moderately small kicks (σ 50 km s-1) are inconsistent with the current observed sample of such DNSs. We discuss the implications of our conclusions for DNS merger rate estimates, of interest to ground-based gravitational wave interferometers. We find that, although orbital evolution due to gravitational radiation affects the eccentricity distribution of the observed sample, the associated upwards correction factor to merger rate estimates is rather small (typically 10%-40%).
The $RO(G)$-graded Serre spectral sequence

x, 72 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
Effect of catalyst used in the sol–gel process on the microstructure and adsorption/desorption performance of silica aerogels

Abstract Silica aerogels prepared by the sol–gel process are often used as solid desiccants in enthalpy wheels for dehumidifying ventilation air in air-conditioning systems. These hygroscopic materials have good moisture adsorption and desorption characteristics due to their porous structure. The current study is focused on the evaluation of the mass diffusivity of silica aerogels, which determines the rate at which a dehumidification process can be performed. The mass diffusivity of silica aerogels is affected by their porous structure which depends on the synthesis technique used to prepare the silica aerogels. The sol–gel process is used to prepared silica aerogels using various basic (ammonium hydroxide, sodium hydroxide, potassium hydroxide) and acidic (hydrofluoric acid, steric acid, hydrogen peroxide) catalysts with the same precipitator (tetramethyl orthosilicate – TMOS) and solvent (methanol). Scanning electron microscopy is used to analyze the microstructure of supercritically dried aerogels. The dynamic vapor sorption method is used to determine the effective mass diffusivity for the different silica aerogels. It is found that the mass diffusivity is related to the microstructure of silica aerogels, which depends on the catalysts used in the sol–gel process. In addition, a parametric study is conducted to determine the effect of relative humidity and temperature on the adsorption and desorption mass diffusivity.
An improved approximation algorithm for the partial Latin square extension problem

Previous work on the partial Latin square extension (PLSE) problem resulted in a 2-approximation algorithm based on the LP relaxation of a three-dimensional assignment IP formulation. We present an e/(e-1)-approximation algorithm that is based on the LP relaxation of a packing IP formulation of the PLSE problem.
Sympathetic control of the circulation in hypertension: lessons from autonomic disorders.

Purpose of the reviewInappropriate sympathetic overactivity is consistently observed in patients with essential hypertension. The present review summarizes the recent advances that have been made in our understanding of the role of the sympathetic nervous system in hypertension.Recent findingsStudie
Failure modes and FEM analysis of power electronic packaging

The development of power electronics technology is driven by the insatiate demand to control electrical power. The new power electronics devices reduce the volume of the converters by three to four orders of magnitude compared to their mercury arc predecessor. And the turn-on and turn-off time has decreased from milliseconds to the microseconds and even nanoseconds, depending on power level. The power range commanded by converters now extends from micro-VA to several hundreds of mega-MVA. Among the new power devices, insulated gate bipolar transistor (IGBT) devices are being more accepted and increasingly used in traction application such as locomotive, elevator, tram and subway. Thus the long-term reliability of IGBT is highly demanded. In this paper the failure modes of power electronics devices especially IGBTs are reviewed. A FEM analysis of a multilayered IGBT packaging module under cyclic thermal loading is presented.
Development of generalized 3-D braiding machines for composite preforms

The operating principles of two prototype braiding machines for the production of generalized braid patterns are described. Both processes afford previously unachievable control of the interlacing of fibers within a textile structure that make them especially amenable to the fabrication of textile preforms for composite materials. They enable independent control of the motion of the individual fibers being woven, thereby enabling the greatest possible freedom in controlling fiber orientation within a structure. This freedom enables the designer to prescribe local fiber orientation to better optimize material performance. The processes have been implemented on a very small scale but at a level that demonstrates their practicality and the soundness of the principles governing their operation.
Computer Rigid Disk Surface Assessment With Laser Interferometry Using DDS

Laser interferomtry in conjunction with the data dependent systems (DDS) methodology is first used in this paper to eliminate errors caused by instrumentation and software, and to recover the surface topography of a computer rigid disk used for illustration. The DDS methodology is then applied once more to decompose the surface height profile into a series of exponential and sinusoidal modes. The significant modes are related to the waviness and surface roughness resulting from different manufacturing processes. Surface reconstruction using only the important modes is presented. This provides a visual as well as mathematical description of the resultant effect of each process. The methodology can characterize very complex surface textures, reducing the reliance on complicated and expensive instruments needed for inspection, and replacing them with relatively inexpensive but reliable computation
Synthesis of 2-alkyl-3-aryl-substituted quinuclidines as novel dopamine transporter inhibitors

Abstract The synthesis of 2-alkyl-3-aryl-substituted quinuclidines was accomplished in a simple synthetic sequence. The separation of enantiomers was carried out using chiral HPLC.
Cation transport using anthraquinone-derived lariat ethers and podands: the first example of electrochemically switched on/off activation/deactivation

Anthraquinone undergoes one- and two-electron reduction to form either radical anions or dianions. When a crown-ether-type macrocycle or a polyethyleneoxy side chain is attached, the reduced aromatic and the oxygen donor groups cooperate to bind the cation. Binding of Li + or Na + is greater when anthraquinone is reduced because there is a charge-charge interaction between it and the cation. This property has been used to facilitate transport. Thus, reduction at the source phase enhances cation binding, and oxidation in the receiving phase induces cation release
Shuttle entry air data system — An experimental investigation of calibration for ascent flight

Abstract An investigation into the calibration of the Shuttle Entry Air Data System (SEADS) has been conducted for the purpose of obtaining angle of attack and sideslip during ascent powered flight. The calibration methodology involves modeling a modified newtonian pressure distribution, corrected for interference, around the orbiter nosecap. Due to the lack of ascent configuration wind tunnel data resolution near the nosecap, the Ascent Air Data System (AADS) was used as a calibrator. The calibration curves were then used to reduce data from future Shuttle flights. Results from this calibration show that vehicle attitude can be determined to within six-tenths degree of pitch and sideslip when compared with the AADS. Calibration curves were then developed using data from two SEADS flights, and the comparison with the AADS system was improved to within one-half degree. Additional flights of the SEADS system should provide more flight calibration data and increase the accuracy of the ascent data reduction method. This paper details the calibration methodology and also presents the results of the calibration when applied to STS-28 and STS-32.
A State Observation Technique for Highly Compressed Source Coding of Autonomous Underwater Vehicle Position

In this paper, a novel technique is presented for using state observers in conjunction with an entropy source encoder to enable highly compressed telemetry of autonomous underwater vehicle (AUV) position vectors. In this work, both the sending vehicle and receiving vehicle or human operator are equipped with a shared real-time simulation of the sender's state based on the prior transmitted positions. Thus, only the innovation between the sender's actual state and the shared state need be sent over the link, such as a very low throughput acoustic modem. The distribution of this innovation can be modeled a priori or assembled adaptively. This distribution is then paired with an arithmetic entropy encoder, producing a very low cost representation of the vehicle's position vector. This system was analyzed on experimental data from the GLINT10 and AGAVE07 expeditions involving two different classes of AUVs performing a diverse number of maneuvers, and implemented on a fielded vehicle in the MBAT12 experiment. Using an adaptive probability distribution in combination with either of two state observer models, greater than 90% compression, relative to a 32-b integer baseline, was achieved.
A Model for Spectral and Compositional Variability at High Energies in Large, Gradual Solar Particle Events

Shocks driven by fast coronal mass ejections (CMEs) are generally believed to be the dominant accelerators in large, gradual solar energetic particle (SEP) events. A key challenge for this notion has been the highly variable spectral and compositional characteristics of these events above a few tens of MeV per nucleon. We have recently proposed that this variability results from the interplay of two factors: evolution in the shock-normal angle as the shock moves outward from the Sun; and a compound seed population, typically comprising at least suprathermals from the corona (or solar wind) and suprathermals from flares. We present here a simple analytical implementation of these ideas. Our calculations semiquantitatively reproduce key features of the observed variability, including spectral morphologies and energy dependence in Fe/O, 3He/4He, and mean ionic charges, in ways that are consistent with correlations in the data. The model makes a prediction for the average high-energy Fe/O enhancement that is borne out by 30 years of observations; the model also provides a quantitative explanation for the Breneman & Stone fractionation effect, a fundamental but previously unexplained aspect of SEP phenomenology. Our calculations must be bolstered by future efforts incorporating realistic CME-shock simulations and a rigorous treatment of particle transport. Suprathermal densities in the corona, as well as details of the injection process at shocks of arbitrary obliquity, require further investigation. Nevertheless, these first results suggest a comprehensive framework for understanding the complexity of high-energy variability in terms of shock physics for most, if not all, large SEP events.
Who was caring for Mary

Abstract An academic physician gives a personal account of his wife’s progressive deterioration during her hospitalization at a university medical center. He encounters physicians who are too distracted by other academic pursuits to care adequately for his wife. Her hospital course is complicated by bilateral pulmonary emboli which occur during inadequate heparin therapy and are followed by myocardial infarction, shock, and the adult respiratory distress syndrome. His experience exemplifies the importance of closely supervised care. He calls on the leaders of academic medical centers to make excellence in patient care a top priority and recommends that clinical as well as esearch skills be rewarded.
Mass-Radius Relation for Magnetic White Dwarfs

Recently, several white dwarfs with very strong surface magnetic fields have been observed. In this paper we explore the possibility that such stars could have sufficiently strong internal fields to alter their structure. We obtain a revised white dwarf mass-radius relation in the presence of strong internal magnetic fields. We first derive the equation of state for a fully degenerate ideal electron gas in a magnetic field using an Euler-MacLaurin expansion. We use this to obtain the mass-radius relation for magnetic 4He, 12C, and 56Fe white dwarfs of uniform composition.
SEARCHES FOR NEW PARTICLES

The status of searches for new particles and new physics during the past year at the Fermilab Tevatron, at HERA and at LEP is summarized. A discussion of the hints for the Standard Model Higgs boson from LEP2 data is presented. Searches for non-Standard Model Higgs bosons are also described. Many searches have been carried out for the particles predicted by supersymmetry theories, and a sampling of these is given. There have also been searches for flavor changing neutral currents in the interactions of the top quark. In addition, searches for excited leptons, leptoquarks and technicolor are summarized.
Counterion adsorption on flexible polyelectrolytes: comparison of theories

Counterion adsorption on a flexible polyelectrolyte chain in a spherical cavity is considered by taking a "permuted" charge distribution on the chain so that the "adsorbed" counterions are allowed to move along the backbone. We compute the degree of ionization by using self-consistent field theory (SCFT) and compare with the previously developed variational theory. Analysis of various contributions to the free energy in both theories reveals that the equilibrium degree of ionization is attained mainly as an interplay of the adsorption energy of counterions on the backbone, the translational entropy of the small ions, and their correlated density fluctuations. Degree of ionization computed from SCFT is significantly lower than that from the variational formalism. The difference is entirely due to the density fluctuations of the small ions in the system, which are accounted for in the variational procedure. When these fluctuations are deliberately suppressed in the truncated variational procedure, there emerges a remarkable quantitative agreement in the various contributing factors to the equilibrium degree of ionization, in spite of the fundamental differences in the approximations and computational procedures used in these two schemes. Furthermore, it is found that the total free energies from the truncated variational procedure and the SCFT are in quantitative agreement at low monomer densities and differ from each other at higher monomer densities. The disagreement at higher monomer densities is due to the inability of the variational calculation to accurately compute the solvent entropy at higher concentrations. A comparison of electrostatic energies (which are relatively small) reveals that the Debye-Huckel estimate used in the variational theory is an overestimation of electrostatic energy as compared to the Poisson-Boltzmann estimate. Nevertheless, since the significant effects from density fluctuations of small ions are not captured by the SCFT, and due to the close agreement between SCFT and the other contributing factors in the more transparent variational procedure, the latter is a better computational tool for obtaining the degree of ionization.
Gedanken densities and exact constraints in density functional theory

Approximations to the exact density functional for the exchange-correlation energy of a many-electron ground state can be constructed by satisfying constraints that are universal, i.e., valid for all electron densities. Gedanken densities are designed for the purpose of this construction, but need not be realistic. The uniform electron gas is an old gedanken density. Here, we propose a spherical two-electron gedanken density in which the dimensionless density gradient can be an arbitrary positive constant wherever the density is non-zero. The Lieb-Oxford lower bound on the exchange energy can be satisfied within a generalized gradient approximation (GGA) by bounding its enhancement factor or simplest GGA exchange-energy density. This enhancement-factor bound is well known to be sufficient, but our gedanken density shows that it is also necessary. The conventional exact exchange-energy density satisfies no such local bound, but energy densities are not unique, and the simplest GGA exchange-energy density is not an approximation to it. We further derive a strongly and optimally tightened bound on the exchange enhancement factor of a two-electron density, which is satisfied by the local density approximation but is violated by all published GGA's or meta-GGA’s. Finally, some consequences of the non-uniform density-scaling behavior for the asymptotics of the exchange enhancement factor of a GGA or meta-GGA are given.
Two Types of X-Ray Spectra in Cataclysmic Variables

We present results of analyses of Chandra HETG soft X-ray spectra (Lambda = 1.5-25 A) of seven cataclysmic variables. We find that these spectra divide unambiguously into two distinct types. Spectra of the first type, consisting of EX Hya, V603 Aql, U Gem, and SS Cyg, are remarkably well fit by a simple cooling flow model, which assumes only steady-state isobaric radiative cooling. This model has only two free parameters, the maximum temperature, kT(sub max), which provides a rough measurement of the depth of the potential well, and the overall normalization, which provides a highly precise measurement of the total accretion rate. Spectra of the second type, consisting of V1223 Sgr, A Psc, and GK Per, are grossly inconsistent with a simple cooling flow model. They instead exhibit a hard continuum, and, in addition, show strong H-like and He-like ion emission but little Fe L-shell emission, which is consistent with expectations for line emission from a photoionized plasma. Using a simple photoionization model, we argue that the observed line emission for these sources can be driven entirely by the hard continuum. The physical significance of these two distinct types of X-ray spectra is also explored.
Redshift Clustering in the Hubble Deep Field

We present initial results from a redshift survey carried out with the low-resolution imaging spectrograph on the 10 m W. M. Keck Telescope in the Hubble Deep Field. In the redshift distribution of the 140 extragalactic objects in this sample, we find six strong peaks with velocity dispersions of ~400 km s-1. The areal density of objects within a particular peak, while it may be nonuniform, does not show evidence for strong central concentration. These peaks have characteristics (velocity dispersions, density enhancements, spacing, and spatial extent) similar to those seen in a comparable redshift survey in a different high Galactic latitude field (Cohen and coworkers), confirming that the structures are generic. They are probably the high-redshift counterparts of huge galaxy structures ("walls") observed locally.
Pricing Loss Leaders Can be Hard

Consider the problem of pricing n items under an unlimited supply with m single minded buyers, each of which is interested in at most k of the items. The goal is to price each item with profit margin p1, p2,…, pn so as to maximize the overall profit. There is an O(k)-approximation algorithm by Balcan and Blum when the price on each item must be above its margin cost; i.e., each pi > 0. We investigate the above problem when the seller is allowed to price some of the items below their margin cost. It was shown by Balcan et al. that by pricing some of the items below cost, the seller could possibly increase the maximum profit by Ω(log n) times. These items sold at low prices to stimulate other profitable sales are usually called “loss leader”. It is unclear what kind of approximation guarantees are achievable when some of the items can be priced below cost. Understanding this question is posed as an open problem by Balcan and Blum. In this paper, we give a strong negative result for the problem of pricing loss leaders. We prove that assuming the Unique Games Conjecture (UGC), there is no constant approximation algorithm for item pricing with prices below cost allowed even when each customer is interested in at most three items. Conceptually, our result indicates that although it is possible to make more money by selling some items below their margin cost, it can be computationally intractable to do so.
Prevention of Intravascular Catheter–Related Infections

Several studies have shown that attention to simple and practical interventions reduces the risk for intravascular catheter–related bloodstream infections. This review updates the expanding body of...
Semi-direct products of lie algebras and their invariants

§1. Preliminaries §2. Generic Stabilisers (centralisers) for the Adjoint Representation §3. Generic Stabilisers for the Coadjoint Representation §4. Semi-Direct Products of Lie Algebras and Modules of Covariants §5. Generic Stabilisers and Rational Invariants for Semi-Direct Products §6. Reductive Semi-Direct Products and their Polynomial Invariants §7. Takiff Lie Algebras and their Invariants §8. The Null-Cone and its Irreducibility §9. Isotropy Contractions and Z2-Contractions of Semisimple Lie Algebras §10. Reductive Takiff Lie Algebras and their Representations §11. On Invariants and Null-Cones for Generalised Takiff Lie Algebras References
Ground state of high-density matter

It is shown that if an upper bound to the false vacuum energy of the electroweak Higgs potential is satisfied, the true ground state of high-density matter is not nuclear matter, or even strange-quark matter, but rather a non-topological soliton where the electroweak symmetry is exact and the fermions are massless. This possibility is examined in the standard SU(3) sub C tensor product SU(2) sub L tensor product U(1) sub Y model. The bound to the false vacuum energy is satisfied only for a narrow range of the Higgs boson masses in the minimal electroweak model (within about 10 eV of its minimum allowed value of 6.6 GeV) and a somewhat wider range for electroweak models with a non-minimal Higgs sector.
Conjugate addition of α-alkoxystannanes via in situ transmetalation using catalytic CuCN

Abstract Catalytic CuCN mediates the in situ transrnetalation of α-thionocarbamoyl stannanes and subsequent conjugate addition to α,β-unsaturated carbonyls in the presence of chlorotrimethlysilane at or a little above room temperature.
Frontiers of Inflationary Cosmology

After a brief review the theory of cosmological perturbations, I highlight some recent progress in the area of reheating in inflationary cosmology, focusing in particular on parametric amplification of super-Hubble cosmological fluctuations, and on the role of noise in the resonance dynamics (yielding a new proof of Anderson localization). I then discuss several important conceptual problems for the current realizations of inflation based on fundamental scalar matter fields, and review some new approaches at solving these problems.
Multiple Flag Varieties of Finite Type

Abstract We classify all products of flag varieties with finitely many orbits under the diagonal action of the general linear group. We also classify the orbits in each case and construct explicit representatives.