cssi/SciSciGPT-SciSciNet huggingface dataset:
Linear, cyclic and polymeric phosphazenes

Abstract An assessment of the diversity of phosphazene chemistry is presented with an emphasis on recent developments and their significance. Fundamental properties of phosphazenes are examined such as structure, nomenclature and bonding, and the various synthetic procedures are catagorized. In addition, the more important reactivity patterns are detailed and analysed. The review compares all systems containing the phosphazene bond, and makes extensive reference to previous reviews on specific types of phosphazene.
Ultrawideband Hybrid EBG/Ferrite Ground Plane for Low-Profile Array Antennas

The design and analysis of an ultrawideband and low-profile hybrid electromagnetic band-gap (EBG)/ferrite ground plane is presented for implementation with antenna systems in airborne foliage penetrating radar and EW applications. The hybrid EBG/ferrite ground plane consists of an EBG structure with a ferrite slab placed on top of the structure's perfect electric conductor (PEC) ground plane. Reflectivity and phase analyses show that the hybrid EBG/ferrite ground plane offers ultrawideband operation beginning in the 100s of MHz with one design version offering an operational bandwidth exceeding 22:1 starting at 170 MHz. Additionally, analysis of the hybrid ground plane implemented with dipole antennas verifies that the hybrid ground plane effectively produces uni-directional radiation for bi-directional radiating antennas. The designed hybrid ground plane is also simulated with Raytheon's long slot array antenna and the obtained results further verify its ultrawideband performance
Target identification performance as a function of temporal and fixed pattern noise

Ronald G. Driggers, MEMBER SPIE Richard Vollmerhausen Keith Krapels, MEMBER SPIE US Army Night Vision and Electronic Sensors Directorate Physics-Based Modeling Branch 10221 Burbeck Rd. Ft. Belvoir, Virginia 22060-5806 E-mail: rdrigger@nvl.army.mil Abstract. With the increased interest and use of staring IR focal plane arrays, the characterization of fixed pattern noise in task performance is becoming more important. Past work includes theoretical treatments and laboratory measurements to describe the characteristics of fixed pattern noise on target acquisition performance. This is the first target acquisition experiment that describes the relative effects of fixed pattern noise and temporal noise on target identification. Static IR tank images are processed with six different levels of fixed pattern noise and six different levels of temporal noise. A perception experiment is performed where 10 U.S. Army soldiers were tasked to identify the tanks through the combinations of noise. Additive noise was applied in both Gaussian and uniform distributions. The results enable a direct comparison between the effects of fixed pattern noise and temporal noise on target identification. © 2001 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.1346583]
The Parameter Variation Problem in State Feedback Control Systems

Abstract : The plant parameter variation problem in multivariable linear systems described by state vector equations is formulated using a new sensitivity measure. This formulation involves a direct comparison of open-loop and state feedback performance in the presence of parameter variations, and provides a basis for guaranteeing the superiority of the feedback design. Results are obtained for both continuous and discrete multiinput multi-output systems. Furthermore, it is shown for single-input multi-output plants that a low sensitivity design is also an optimal feedback control design with respect to a quadratic performance index. This provides a new interpretation of a similar result previously obtained by Kalman. (Author)
The matching of structural elements in reactions for evaluating stabilization energies for benzene and monosilabenzene

Using the 6-31G* basis set the stabilization energy for monosilabenzene has been calculated as ΔET for the homodesmotic reactions in which (i) ethylene is the other reactant with trans 1,3-butadiene and trans 2-sila-1,3-butadiene as the products, and (ii) trans 1,3-butadiene is the other reactant with trans 1,3,5-hexatriene and trans 3-sila-1,3,5-hexatriene as the products. The values are 17.2 and 17.6 kcal mol−1 respectively, compared to 24.8 and 23.5 kcal mol−1 respectively for the corresponding reactions of benzene. The difference is ΔET for the interchange of =SiH- and =CH- groups between the aromatic and aliphatic structural environments, and is thus more informative than the quotient. The extent of the matching of structural elements in these reactions, and in the benzene reactions using longer chain polyenes, is assessed in terms of the structural environment about each heavy atom in its entirety — namely the nearest neighbor atoms (NN), the next nearest neighbor atoms (NNN), and the more distant atoms (NNNN and NNNNN). Matching by number alone is designated “isoplesiotic”, and if by both number and kind, “homoplesiotic”.
On the Discharge of Negative Electricity from Hot Calcium and from Lime

The discharge of electricity from hot metals has been the subject of a great number of researches by different authors. The metal chiefly used in these experiments has been platinum, on account of its high melting-point, its stability in air, and the ease with which it can he obtained in a state of purity. In the present experiments calcium was chosen for investigation because of its strong electropositive character. Since this implies a great attraction for positive electricity, it would be expected that the negative corpuscles would escape more readily from calcium than from platinum. It should, therefore, be possible to obtain a measurable “negative leak” from calcium at a much lower temperature than from platinum or other less electropositive metal. The first method of experimenting employed consisted in measuring the saturation current from an electrically heated calcium wire to a surrounding electrode, both being placed in a vacuum, but it was found to be impossible to get a clean surface of calcium in this way, for the metal combines with the oxygen, nitrogen, and water vapour in the air, and becomes more or less covered with a coating of calcium compounds before the apparatus can be fitted up. Another difficulty was soon discovered. When the wire was heated to above a dull red heat, the vapour pressure of the metal was sufficient for it to volatilize and condense on the colder walls of the tube. Thus the wire got thinner at its hottest point, and, consequently, the temperature there rose, and the sublimation increased, until in a few seconds the wire had broken through.
Storage of light in atomic vapor.

We report an experiment in which a light pulse is effectively decelerated and trapped in a vapor of Rb atoms, stored for a controlled period of time, and then released on demand. We accomplish this ``storage of light'' by dynamically reducing the group velocity of the light pulse to zero, so that the coherent excitation of the light is reversibly mapped into a Zeeman (spin) coherence of the Rb vapor.
THE ELUSIVE HIGGS BOSON(S)

We outline the motivations for having a light Higgs boson with fairly SM-like couplings to WW, ZZ but with unusual decays that elude LEP limits and that will also make its detection at the LHC quite challenging. The Next-to-Minimal Supersymmetric Model provides a very appealing model of this type.
M giant kinematics in off-axis fields between 150 and 300 parsecs from the galactic center

We present radial velocities for approximately 40 stars in each of four optically obscured, off-axis fields toward the Galactic bulge. The mean heliocentric radial velocity and velocity dispersion are −75 ± 24 km s−1 and 127 ± 16 km s−1, 2 ± 23 km s−1 and 127 ± 14 km s−1, −14 ± 22 km s−1 and 126 ± 14 km s−1, and −31 ± 28 km s−1 and 153 ± 17 km s−1 for fields located at 299, 288, 171, and 160 pc projected radius, respectively. The dispersions generally match Kent’s (1992) axisymmetric mass model but may be higher than the model’s predictions at small projected radius.
PM: A metrics-driven plan compiler

Abstract The goal of the Partial Metrics (PM) project is to investigate the metrics-driven acquisition of planning knowledge. The approach taken here can be thought of as reverse compilation. Abstract plans are generated from source programs in a given target language. This process involves the integration of traditional compiler techniques with certain AI paradigms. This paper describes the current prototype's design. The prototype's capabilities are demonstrated by taking an Ada target program generated by a plan in the Programmer's Apprentice system and creating another plan using the PM knowledge compiler. The plan produced by the prototype possesses many of the original plan's features.
A novel surface-emitting laser using leaky mode output coupling

A novel surface-emitting laser design that utilizes leaky mode emission is proposed. Power is coupled out of the active layer in a narrow beam by monolithically integrating a prism-like structure with a conventional semiconductor laser. Threshold current densities and external efficiencies approximately 1 kA / cm2 and 0.3, respectively, are estimated.
Methods and options for the heterologous production of complex natural products

This review will detail the motivations, experimental approaches, and growing list of successful cases associated with the heterologous production of complex natural products.
Contributions to the implementation of the Arakawa-Schubert cumulus parameterization in the GLA GCM

The roles of the Critical Cloud Work Function (CCWF) data set and the upper and lower bounds on entrainment by cumulus plumes in the Arakawa-Schubert cumulus parameterization (ASCP) in the GLA GCM (Geller et al., 1988) were investigated in two sets of experiments. It was found that the horizontal and vertical distribution of cumulus heating can be altered in ASCP by adjusting these parameters. These changes can have a strong influence on the vertical structure of condensation heating, water vapor distribution, temperature, and rainfall. The CCWF is an important limiting parameter that controls the onset of different cloud types; increasing the threshold values of CCWF for all clouds tends to concentrate the rainfall into a narrower ITCZ and affects the rainfall during the initial adjustment period.
Modeling Carbon Chain Anions in L1527

The low-mass protostellar region L1527 is unusual because it contains observable abundances of unsaturated carbon-chain molecules including CnH radicals, H2Cn carbenes, cyanopolyynes, and the negative ions C4H− and C6H−, all of which are more associated with cold cores than with protostellar regions. Sakai et al. suggested that these molecules are formed in L1527 from the chemical precursor methane, which evaporates from the grains during the heat-up of the region. With the gas-phase osu.03.2008 network extended to include negative ions of the families C−n, and CnH−, as well as the newly detected C3N−, we modeled the chemistry that occurs following methane evaporation at T ≈ 25–30 K. We are able to reproduce most of the observed molecular abundances in L1527 at a time of ≈5 × 103 yr. At later times, the overall abundance of anions become greater than that of electrons, which has an impact on many organic species and ions. The anion-to-neutral ratio in our calculation is in good agreement with observation for C6H−, but exceeds the observed ratio by more than 3 orders of magnitude for C4H−. In order to explain this difference, further investigation is needed on the rate coefficients for electron attachment and other reactions regarding anions.
City government structure: are some institutions undersupplied?

City councilors have a vested interest in maintaining the local government structure that got them elected. This resistance to change may result in non-optimal supplies of particular local political institutions as cities and metropolitan areas experience changes in population and diversity. Using unique data from the State of Florida, we show that there is an undersupply of cities offering larger council sizes. Our evidence also suggests that there is no undersupply of cities with the mayor-council versus the council-manager form of government or cities with at-large versus district election methods.
Optimal short range trajectories for helicopters

An optimal flight path algorithm using a simplified altitude state model and a priori climb cruise descent flight profile was developed and applied to determine minimum fuel and minimum cost trajectories for a helicopter flying a fixed range trajectory. In addition, a method was developed for obtaining a performance model in simplified form which is based on standard flight manual data and which is applicable to the computation of optimal trajectories. The entire performance optimization algorithm is simple enough that on line trajectory optimization is feasible with a relatively small computer. The helicopter model used is the Silorsky S-61N. The results show that for this vehicle the optimal flight path and optimal cruise altitude can represent a 10% fuel saving on a minimum fuel trajectory. The optimal trajectories show considerable variability because of helicopter weight, ambient winds, and the relative cost trade off between time and fuel. In general, reasonable variations from the optimal velocities and cruise altitudes do not significantly degrade the optimal cost. For fuel optimal trajectories, the optimum cruise altitude varies from the maximum (12,000 ft) to the minimum (0 ft) depending on helicopter weight.
Alternating group covers of the affine line

For an odd prime p t= 2 mod 3, we prove Abhyankar’s Inertia Conjecture for the alternating group A p+2, by showing that every possible inertia group occurs for a (wildly ramified) A p+2-Galois cover of the projective k-line branched only at infinity where k is an algebraically closed field of characteristic p > 0. More generally, when 2 ≤ s < p and gcd(p−1, s+1) = 1, we prove that all but finitely many rational numbers which satisfy the obvious necessary conditions occur as the upper jump in the filtration of higher ramification groups of an A p+s -Galois cover of the projective line branched only at infinity.
Corrosion of Modular Titanium Alloy Stems in Cementless Hip Replacement

Severe, localized corrosion of titanium-alloy femoral stems has been reported for specific designs of hip prostheses intended for fixation using acrylic cement. The purpose of the present study was to examine the possibility that corrosion might also occur when titanium-alloy stems are inserted without cement, but the body of the stem is modular in design. Fourteen (7 primary and 7 revision) cementless, modular-body, titanium-6% aluminum-4% vanadium alloy femoral stems of similar design were removed at revision surgery after 2 to 108 months in situ. The reason for removal was unexplained pain (4), femoral or acetabular loosening (4), infection (3), recurrent dislocation (2), or component malposition (1). The devices and, in selected cases, tissue from the joint psuedocapsule were studied with the use of light and scanning electron microscopy. Fretting corrosion products were characterized using energy dispersive x-ray analysis, selected area diffraction, and micro-Raman spectroscopy. Damage at the modular body connections was absent in 3 stems, mild in 6, moderate in 4, and severe in 1. The surface damage was characterized predominately by fretting scars and by pitting and etching. Thick deposits of mixed titanium oxides were found adherent to the stem at the sites of corrosion and as 0.01 to 200 micrometer particles within histiocytes and multinucleated giant cells in the joint pseudocapsule. Fretting corrosion at the modular-body junctions of titanium-alloy femoral stems can generate solid degradation products, adding to the particulate burden of the periprosthetic tissues and potentially accelerating bearing-surface wear by a third-body mechanism. Both of these features can potentiate the development and progression of osteolysis. In addition, fretting corrosion can increase the potential for structural failure of the device. These findings stress the importance of the design of modular junctions to minimize corrosion and the generation of corrosion products.
On Reliable Topological Structures for Message-Switching Communication Networks

The synthesis of optimal reliable (invulnerable) topological structures for message-switching communication networks is considered. The connectivity of the underlying graphs is used as a measure of the network invulnerability. The maximal average message delay value is utilized as the network delay measure. Simultaneously with choosing the topological structure, optimal line capacities are assigned. Therefore, the performance measure of a given network structure is chosen to be given by its delay-capacity product function, incorporating the product of the prescribed network maximal delay value and the associated minimal overall line capacity value. The latter involves a distance-independent link cost function incorporating the line capacity. A general routing discipline is used to account for dynamic updating of fixed routing procedures, needed to accomodate terminal traffic flow fluctuations. n -node k -connected graphs yielding networks with minimal delaycapacity product functions are characterized and realized. Complete networks (utilizing direct dedicated lines) are shown to be optimal if the resulting lines have a high average line utilization value. Otherwise (under appropriate symmetry conditions on the network traffic matrix), the optimal message-switching reliable network structures are characterized by a family of graphs of diameter two. The latter thus allow between any pair of nodes a route which is either a direct line or contains a single intermediate node. Also noted is a family of k -connected networks, for which the delay-capacity product function is not increased by more than twice upon the failure of (k-1) or less nodes or lines.
The Impacts of Gender Differences in Social Capital on Microenterprise Business Start-Up

The Microenterprise Development Programs (MDPs) in the United States provide low-income women with business training and loans for their business start-up. This study investigates whether gender di...
Finite-temperature collapse of a Bose gas with attractive interactions

We study the mechanical stability of the weakly interacting Bose gas with attractive interactions, and construct a unified picture of the collapse valid from the low-temperature condensed regime to the high temperature classical regime. As we show, the noncondensed particles play a crucial role in determining the region of stability, including providing a mechanism for collapse in the noncondensed cloud. Furthermore, we demonstrate that the mechanical instability prevents BCS-type ``pairing'' in the attractive Bose gas. We extend our results to describe domain formation in spinor condensates.
Evaluation of adaptive phased array antenna, far-field nulling performance in the near-field region

A theory for analyzing the behavior of adaptive phased array antennas illuminated by a near-field interference test source is presented. Conventional phased array near-field focusing is used to produce an equivalent far-field antenna pattern at a range distance of one to two aperture diameters from the adaptive antenna under test. The antenna is assumed to be a linear array of isotropic receive elements. The interferer is assumed to be a bandlimited noise source radiating from an isotropic antenna. The theory is developed for both partially and fully adaptive arrays. Results are presented for the fully adaptive array case with single and multiple interferers. The results indicate that near-field and far-field adaptive nulling can be equivalent. The adaptive nulling characteristics studied in detail are the array radiation patterns, adaptive cancellation, covariance matrix eigenvalues, and adaptive array weights. >
Integrability of a disordered Heisenberg spin-1/2 chain

We investigate how the transition from integrability to nonintegrability occurs by changing the parameters of the Hamiltonian of a Heisenberg spin-1/2 chain with defects. Randomly distributed defects may lead to quantum chaos. A similar behaviour is obtained in the presence of a single defect out of the edges of the chain, suggesting that randomness is not the cause of chaos in these systems, but the mere presence of a defect.
Decreasing morbidity following laryngotracheal reconstruction in children.

Our objectives are to report (1) methods for decreasing infectious complications and excessive weakness associated with the period of sedation and neuromuscular blockade (NMB) following single-stage laryngotracheal reconstruction (SSLTR); (2) an association between gastroesophageal reflux (GER) and subglottic stenosis (SGS); (3) results of 21 SSLTRs and 15 two-stage LTRs (TSLTRs). A retrospective chart review was performed for the period January, 1990-August, 1995, including 36 patients who had 38 LTRs for SGS and/or posterior glottic stenosis at a tertiary care center. Our most recent post-SSLTR protocol included: (1) prophylactic antimicrobials (clindamycin plus antipseudomonal agents = C+ A); (2) GER treatment; (3) titrated infusion NMB with daily recovery of neuromuscular function; (4) avoidance of prolonged simultaneous administration of NMB and corticosteroids. Patients who had prophylactic antimicrobials (C + A) during intubation following SSLTR had fewer (113, 8%) postoperative infectious complications than patients who received other/no antibiotics (48, 50%) (P < 0.05). Avoidance of prolonged simultaneous administration of NMB and corticosteroids and use of titrated infusion of NMB with daily recovery of neuromuscular function was associated with less weakness following extubation (011, 0% vs. 46, 66%) (P < 0.002). Of 26 patients tested for GER, 21 (81%) had at least one positive test, suggesting a significant association between GER and SGS (P < 0.05). The overall success rate for LTR was 3336 or 92%. SSLTR had a 95% success rate while two-stage LTR had an 87% success rate, although two revisions were required. Prophylactic antimicrobials, improved postoperative management and GER treatment allowed successful LTRs with decreased infectious complications and less weakness.
The Ultramassive White Dwarf EUVE J1746–706*

We have obtained new optical and extreme ultraviolet (EUV) spectroscopy of the ultramassive white dwarf EUVE J1746-706. We revise Vennes et al.'s original estimates of the atmospheric parameters, and we measure an effective temperature of 46,500 ± 700 K and a surface gravity log g = 9.05 ± 0.15 (~1.2 M☉), in agreement with Balmer line profiles and the EUV continuum. We derive an upper limit on the atmospheric abundance of helium of He/H = 1.3 × 10-4 and a neutral hydrogen column density in the local interstellar medium NH I = 1.8 ± 0.4 × 1019 cm-2 from the EUV spectrum. Our upper limit corresponds to half the helium abundance observed in the atmosphere of the ultramassive white dwarf GD 50. We discuss the possibility that EUVE J1746-706 represents an earlier phase of evolution relative to GD 50 and may, therefore, help us understand the origin and evolution of massive white dwarfs.
Direct α-hydroxylation of ketones under acidic conditions using [bis (trifluoroacetoxy)] iodobenzene

Abstract [Bis(trifluoroacetoxy)] iodobenzene and trifluoroacetic acid in CH3CN/H2O reacts with aromatic, heteroaromatic, and aliphatic ketones to afford α-hydroxyketones in moderate to good yields.
TIME-DISTANCE SEISMOLOGY OF THE SOLAR CORONA WITH CoMP

We employ a sequence of Doppler images obtained with the Coronal Multi-channel Polarimeter (CoMP) instrument to perform time-distance seismology of the solar corona. We construct the first k-ω diagrams of the region. These allow us to separate outward and inward propagating waves and estimate the spatial variation of the plane-of-sky-projected phase speed, and the relative amount of outward and inward directed wave power. The disparity between outward and inward wave power and the slope of the observed power-law spectrum indicate that low-frequency Alfvenic motions suffer significant attenuation as they propagate, consistent with isotropic MHD turbulence.
Answering Lord Perry's question: dissecting regulatory overfishing

Abstract In 1995, in response to the distressed condition of the British fishing industry, the House of Lords held a series of hearings on “Fish Stock Conservation and Management.” Lord Perry of Walton posed the straightforward question of why regulation was not succeeding: If one takes all the management systems into account—TACs [total allowable catches, or annual quotas], number of days at sea and the decommissioning programme—none of them has stopped the gross over-fishing that has taken place. There seem to be three factors to account for it: first, the scientific advice that is given; secondly, how far that advice is accepted by politicians who set the TACs and quotas; and, thirdly, whether the fishermen obey the regulations. Which of these are the most at fault at the moment? Lord Perry's question led us to ask to what degree publicly available information in the United States could shed light on the sources of overfishing in individual fisheries—what we will call “regulatory overfishing.” First, we set out a typology of the potential sources of regulatory overfishing. Next, we examine two case illustrations of federally managed, overfished fisheries in the United States. Each case generates important insights into the causes of regulatory overfishing and lessons for future management. In the final section of the paper, we make several suggestions aimed at improving fisheries management and the management process.
Investigation of the N-arylation of various substituted indoles using microwave-assisted technology

Various substituted indoles were reacted with activated aryl-fluorides using microwave-assisted technology in the construction of N-aryl bonds.
The exceptional set in Vojta’s conjecture for algebraic points of bounded degree

We study the dependence on various parameters of the exceptional set in Vojta's conjecture. In particular, by making use of certain elliptic surfaces, we answer in the negative the often-raised question of whether Vojta's conjecture holds when extended to all algebraic points (that is, if the conjecture holds without fixing a bound on the degree of the algebraic points).
A modified ubbelohde viscometer with improved dilution characteristics

Abstract A simple modification of the standard Ubbelohde dilution viscometer is proposed. It consists of replacing the commercially supplied dilution reservoir with a siphon tube leading to a much larger custom-built storage container. Typically, the usual twofold dilution capability of commercial pieces can be increased to as much as ten- or twelvefold without loss of accuracy. Examples are presented illustrating how this modification simplifies and accelerates data acquisition for the routine measurement of polymer intrinsic viscosity and in addition allows for the use of very small quantities of polymer. The former point is illustrated through routine measurement of the intrinsic viscosity of a thermoplastic polyelectrolyte polymer containing 2-hydroxyethyl methacrylate and methacrylic acid, and the latter through an analysis of changes in intrinsic viscosity accompanying thermally induced chain scission in “Phenoxy” resin (Union Carbide, poly(bis-phenol-A, 2-hydroxypropylether)).
Lower-Pole Caliceal Stone Clearance After Shockwave Lithotripsy, Percutaneous Nephrolithotomy, and Flexible Ureteroscopy: Impact of Radiographic Spatial Anatomy

Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP 3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.
Spectral flow, condensate and topology in lattice QCD

Abstract We study the spectral flow of the Wilson-Dirac operator H (m) with and without an additional Sheikholeslami-Wohlert (SW) term on a variety of SU(3) lattice gauge field ensembles in the range 0 ⩽ m ⩽ 2. We have used ensembles generated from the Wilson gauge action, an improved gauge action, and several two-flavor dynamical quark ensembles. Two regions in m provide a generic characterization of the spectrum. In region I defined by m ⩽ m1, the spectrum has a gap. In region II defined by m1 ⩽ m ⩽ 2, the gap is closed. The level crossings in H (m) that occur in region II correspond to localized eigenmodes and the localization size decreases monotonically with the crossing point down to a size of about one lattice spacing. These small modes are unphysical, and we find the topological susceptibility is relatively stable in the part of region II where the small modes cross. We argue that the lack of a gap in region II is expected to persist in the infinite volume limit at any gauge coupling. The presence of a gap is important for the implementation of domain wall fermions.
High performance linear-quadratic and H-infinity designs for a 'supermaneuverable' aircraft

Recent efforts by the National Aeronautics and Space Administration Langley Research Center have focused on expanding the flight envelope of the F/A-18 aircraft. Of particular concern has been the low speed, high angle-of-attack regime over which the conventional aerodynamic controls of the F/A-18 lose their effectiveness. In order to address this problem the F18 high alpha research vehicle was developed. This aircraft is essentially a modified F/A-18 which possesses thrust vectoring capabilities and hence increased maneuverability in this flight regime. The linear-quadratic-Gaussian with loop-transfer-recovery and H(infinity) design methodologies are used to design high performance controllers for the F18 at an operating point within the expanded envelope. In addition, how the control redundancy of the F18 can be used to maintain nominal performance, as well as nominal stability, in situations where failures occur, is shown.
Estrogens and progestins in the management of primary hyperparathyroidism

One of the common dilemmas in clinical endocrine practice is the management of patients with hyperparathyroidism (HPT) who either cannot or will not undertake definitive surgical treatment. Therapeutic decisions would be simplified by the availability of a nonsurgical approach to control biochemical abnormalities and forestall the consequences of this condition. In the short term, oral phosphorus salts can be safe and effective. For chronic therapy, only estrogens and progestins have been examined in sufficient detail to merit discussion. Estrogens normalize serum and urinary calcium in the majority of older women with HPT. Biochemical control is generally maintained for as long as patients continue treatment. The data support the view that estrogen inhibits the actions of PTH, particularly on bone, but does not reduce the abnormal PTH secretion. Androgenic progestins may also lower serum and urinary calcium in HPT, but current data suggest that normalization of serum calcium levels is more likely to occur with estrogen. Although reduction in urinary calcium excretion should prove effective in preventing nephrolithiasis, it is unclear whether hormone therapy provides protection against fracture. Whether or not hormone replacement is prescribed, nonsurgical management requires a highly committed patient who is willing to undergo extensive and prolonged follow-up.
Integrals of equivariant forms and a Gauss–Bonnet theorem for constructible sheaves

Abstract The Berline–Vergne integral localization formula for equivariantly closed forms ([N. Berline, M. Vergne, Classes caracteristiques equivariantes. Formules de localisation en cohomologie equivariante, C. R. Acad. Sci. Paris 295 (1982) 539–541], Theorem 7.11 in [N. Berline, E. Getzler, M. Vergne, Heat Kernels and Dirac Operators, Springer-Verlag, 1992]) is well-known and requires the acting Lie group to be compact. In this article, we extend this result to real reductive Lie groups G R . As an application of this generalization, we prove an analogue of the Gauss–Bonnet theorem for constructible sheaves. If F is a G R -equivariant sheaf on a complex projective manifold M , then the Euler characteristic of M with respect to F χ ( M , F ) = 1 ( 2 π ) dim C M ∫ Ch ( F ) χ g C ˜ as distributions on g R , where Ch ( F ) is the characteristic cycle of F and χ g C ˜ is the Euler form of M extended to the cotangent space T ∗ M (independently of F ). We also consider an analogue of Duistermaat–Heckman measures for real reductive Lie groups acting on symplectic manifolds. In [M. Libine, Riemann–Roch–Hirzebruch integral formula for characters of reductive Lie groups, Represent. Theory 9 (2005) 507–524. Also math.RT/0312454 ] I apply the results of this article to obtain a Riemann–Roch–Hirzebruch type integral formula for characters of representations of reductive groups.
Computing genus 2 curves from invariants on the Hilbert moduli space

Abstract We give a new method for generating genus 2 curves over a finite field with a given number of points on the Jacobian of the curve. We define two new invariants for genus 2 curves as values of modular functions on the Hilbert moduli space and show how to compute them. We relate them to the usual three Igusa invariants on the Siegel moduli space and give an algorithm to construct curves using these new invariants. Our approach simplifies the complex analytic method for computing genus 2 curves for cryptography and reduces the amount of computation required.
Morphological Evolution of Distant Galaxies from Adaptive Optics Imaging

We report here on a sample of resolved, infrared images of galaxies at z ~ 0.5 taken with the 10 m Keck Telescope's adaptive optics system. We regularly achieve a spatial resolution of 005 and are thus able to resolve both the disk and bulge components. We have extracted morphological information for 10 galaxies and compared their properties to those of a local sample. The selection effects of both samples were explicitly taken into account in order to derive the unbiased result that disks at z ~ 0.5 are ~0.6 mag arcsec-2 brighter than, and about the same size as, local disks. The case with no luminosity evolution is ruled out at 90% confidence. We also find, in a more qualitative analysis, that the bulges of these galaxies have undergone a smaller amount of surface brightness evolution and have also not changed significantly in size from z ~ 0.5 to today. This is the first time this type of morphological evolution has been measured in the infrared and it points to the unique power of AO in exploring galaxy evolution.
Measuring Endoscopic Performance for Colorectal Cancer Prevention Quality Improvement in a Gastroenterology Practice

A gastroenterology practice lacked quality measures to evaluate the practice's colorectal cancer prevention efforts. Colonoscopy performance data were gathered from a retrospective review of 90 charts using a modified Colorectal Cancer Prevention Data Collection Form. Practice stakeholders and project leader reviewed the data, identified practice deficiencies, conducted root cause analysis, and developed practice changes. Implementing the prioritized recommendations and routinely benchmarking care were warranted to ensure effective practice to improve outcomes for colorectal cancer prevention. Achieving higher-value care has led to increased efforts to improve systems for measuring care, using these measures for quality improvement and directly linking quality outcomes to reimbursement.
Can the Super-Kamiokande atmospheric data predict the solar neutrino deficit?

In this letter we show that the evidence for neutrino oscillations from the super-Kamiokande atmospheric neutrino data fully determines the 3×3 neutrino-oscillations mixing matrix and predicts an energy-independent solar neutrino deficit at the level of 45%. This corresponds to a ratio of measured to predicted neutrino flux of , in good agreement with the experimental results. We achieve this result within the framework of a minimal, three-generation neutrino mixing, with mass squared differences of ΔM2≃0.45 eV2 and . The mixing matrix derived here is characterized by the mixing angles θ=35.1°, β=5.5° and ψ=23.3°, and a vanishing CP-violating phase, δ=0.
Shear transformation zone dynamics model for metallic glasses incorporating free volume as a state variable

Abstract A mesoscale model, shear transformation zone dynamics (STZ dynamics), is employed to investigate the connections between the structure and deformation of metallic glasses. The present STZ dynamics model is adapted to incorporate a structure-related state variable, and evolves via two competing processes: STZ activation, which creates free volume, vs. diffusive rearrangement, which annihilates it. The dynamical competition between these two processes gives rise to an equilibrium excess free volume that can be connected to flow viscosity via the phenomenological Vogel–Fulcher–Tammann relation in relaxed structures near the glass transition temperature. On the other hand, the excess free volume allows glasses to deform at low temperatures via shear localization into shear bands, even in the presence of internal stress distributions that arise upon cooling after processing.
Dynamic mode decomposition for large and streaming datasets

We formulate a low-storage method for performing dynamic mode decomposition that can be updated inexpensively as new data become available; this formulation allows dynamical information to be extracted from large datasets and data streams. We present two algorithms: the first is mathematically equivalent to a standard “batch-processed” formulation; the second introduces a compression step that maintains computational efficiency, while enhancing the ability to isolate pertinent dynamical information from noisy measurements. Both algorithms reliably capture dominant fluid dynamic behaviors, as demonstrated on cylinder wake data collected from both direct numerical simulations and particle image velocimetry experiments.
Reaction of hexamethyldisiloxane with 2-ethoxy-1,3-dioxolane

The reaction of hexamethyldisiloxane with 2-ethoxy-1,3-dioxolane is described. It is shown that cleavage of the endo- and exocyclic carbon-oxygen bonds of the ortho ester occurs under mild conditions (16–20‡C) in the presence of acidic catalysts with the formation of 2-(trimethylsiloxy)ethyl formate, the subsequent transformation of which leads to ethyl formate, trimethylethoxysilane, and 1,2-bis(trimethylsiloxy)ethane.
Zonal Jets as Transport Barriers in Planetary Atmospheres

Abstract The connection between transport barriers and potential vorticity (PV) barriers in PV-conserving flows is investigated with a focus on zonal jets in planetary atmospheres. A perturbed PV staircase model is used to illustrate important concepts. This flow consists of a sequence of narrow eastward and broad westward zonal jets with a staircase PV structure; the PV steps are at the latitudes of the cores of the eastward jets. Numerically simulated solutions to the quasigeostrophic PV conservation equation in a perturbed PV staircase flow are presented. These simulations reveal that both eastward and westward zonal jets serve as robust meridional transport barriers. The surprise is that westward jets, across which the background PV gradient vanishes, serve as robust transport barriers. A theoretical explanation of the underlying barrier mechanism is provided. It is argued that transport barriers near the cores of westward zonal jets, across which the background PV gradient is small, are found in Jupi...
Approximate Sum-Capacity of K-user Cognitive Interference Channels with Cumulative Message Sharing

This paper considers the K-user cognitive interference channel with one primary and K-1 secondary/cognitive transmitters with a cumulative message sharing structure, i.e., cognitive transmitter i ϵ [2 : K] has non-causal knowledge of the messages of users with index less than i. A computable outer bound valid for any memoryless channel is proposed. The sum-rate outer bound is evaluated first for the high-SNR linear deterministic approximation of the Gaussian noise channel. This is shown to be both the sum capacity for the 3-user channel with arbitrary channel gains, and the sum-capacity for the symmetric K-user channel. Interestingly, for the K user channel, cognition at transmitters 2 to K-1 is not needed, and knowledge of all messages at the K-th transmitter only is sufficient to achieve the sum-capacity. Next, the sum-capacity of the symmetric Gaussian noise channel is characterized to within a constant additive and multiplicative gap, both of which are functions of K. As opposed to other multiuser interference channel models, a single scheme (in this case based on dirty-paper coding) suffices for both the weak and strong interference regimes. The generalized degrees of freedom (gDoF) are then derived and are shown, unlike interference and broadcast channels, to be a function of K. Interestingly, it is shown that as the number of users grows to infinity the gDoF of the K-user cognitive interference channel with cumulative message sharing tends to the gDoF of a broadcast channel with a K-antenna transmitter and K single-antenna receivers. Finally, numerical evaluations show that the actual gaps between the presented inner and outer bounds are significantly smaller than the analytically derived gaps.
Haptic interaction with fluid media

We present a method for integrating force feedback with interactive fluid simulation. We use the method described to generate haptic display of an incompressible NavierStokes fluid simulation. The force feedback calculation is based on the equations of fluid motion, and enables us to generate forces as well as torques for use with haptic devices capable of delivering torque. In addition, we adapt our fluid-haptic feedback method for use in a painting application that is based on fluid simulation, enabling the artist to feel the paint. Finally we describe a force filtering technique to reduce the artifacts that result from using 60Hz simulation data to drive the 1KHz haptic servo loop, a situation which often arises in practice.
Experimental Evidence for Wolf Shifts of Cyclostationary Fields

Previously predicted shifts in the generalized spectra of cyclostationary fields are demonstrated experimentally. These results apply to stochastic fields with periodic statistics, e.g. the pulse trains of comb spectroscopy or fields produced by mode-locked lasers.
Lens space surgeries and a conjecture of Goda and Teragaito

Using work of Ozsvath and Szabo, we show that if a nontrivial knot in S 3 admits a lens space surgery with slope p, then p � 4g+3, where g is the genus of the knot. This is a close approximation to a bound conjectured by Goda and Teragaito.
A Chiral Sulfoxide-Ligated Ruthenium Complex for Asymmetric Catalysis: Enantio- and Regioselective Allylic Substitution

The design and synthesis of a novel chiral sulfoxide-ligated cyclopentadienyl ruthenium complex is described. Its utility as an asymmetric variant of [CpRu(MeCN)3]PF6 is demonstrated through its ability to function in the branched-selective asymmetric allylic alkylation of phenols and carboxylic acids. Water has also been shown to act as a competent nucleophile in this reaction to generate branched allyl alcohols with good regio- and enantioselectivities.
Algorithms And Programs For Strong Gravitational Lensing In Kerr Space-time Including Polarization

Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing strong lensing effects of Kerr black holes, including effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are: a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using ‘mpi4py’ package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity-related computations using interpreted languages such as MATLAB and Python. Subject headings: accretion, accretion disks — polarization — gravitational lensing: strong — quasars: supermassive black holes
Tetrakis(trimethylsilyl)silane

Abstract Details are provided for the preparation of tetrakis(trimethylsilyl)silane, and a discussion of its properties and mechanisms of formation are presented. The unique physical and chemical properties associated with this compound have been attributed to its high degree of symmetry and its branched-chain structure.
Radiation Hardened PMOS Process with Ion Implanted Threshold Adjust

Radiation effects on MOS devices have been extensively investigated and minimized by processing modifications. Generally, the use of ion implantation through the gate oxide is avoided to ensure gate oxide integrity when fabricating radiation hardened integrated circuits. A p-channel metal gate MOS integrated circuit process (space flight qualified) relying on ion implantation has been developed and evaluated. Ion implantation of boron eleven (B") at 56 KeV is utilized for depletion resistor formation and for adjusting the p-channel enhancement transistor threshold voltage. PMOS large scale integrated (LSI) circuits performed successfully after gamma irradiation of 6×105 rads silicon. Individual hardened p-channel transistors (ion implanted) experienced about 0.5v shift in threshold voltage after this dose. Parameters monitored on an LSI as a function of the integrated dose included gate threshold voltage, count pulse width, power consumption, count rate and shift rate. All parameters exhibited some shift from the initial pre-irradiation values but were well within specified tolerance levels after the 6×105 rad dosage. Subsequent annealing of the irradiated integrated circuits for 24 hours at 250°C N2 restored all chips to their pre-irradiation condition. This paper will present the process modifications, testing and results of our fully ion implanted radiation hard PMOS process.
Millimeter/submillimeter nonlinear spectroscopy

The techniques of coherent transient spectroscopy have been successfully applied to the microwave and optical regions of the spectrum, but lack of suitable sources has prevented convenient extension to the millimeter/submillimeter region where several strong molecular transitions occur. Analysis of the experimental requirements and theory for such experiments considering several molecules including H2O and CH3Cl indicates how such experiments can be performed employing recently developed oscillators with increased power.