cssi/SciSciGPT-SciSciNet huggingface dataset:
On Eckl’s pseudo-effective reduction map

Suppose that X is a complex projective variety and L is a pseudo-effective divisor. A numerical reduction map is a quotient of X by all subvarieties along which L is numerically trivial. We construct two variants: the L-trivial reduction map and the pseudo-effective reduction map of [Eckl05]. We show that these maps capture interesting geometric properties of L and use them to analyze abundant divisors.
Transport dynamics of mass failures along weakly cohesive clinoform foresets

This study addresses the initiation mechanisms of mass failures on clinoform foresets. Previous studies have created mass flows by releasing dense water–sediment mixtures into standing water, thus imposing the initial conditions for the mass failures rather than allowing them to form on their own. Para-meters such as the density, composition and initial momentum of the failures are pre-determined, precluding observation of the factors that set them initially. This study uses a new experimental method that allows a range of mass failures to self-generate. Building a clinoform using a cohesive mixture of walnut-shell sand and kaolinite allows the foreset to build up and fail episodically, generating mass failures. Slopes undergo a series of morphological changes prior to failure, creating a concave shape that becomes exaggerated as deposition continues. This morphology leaves the slope in a metastable state. Once the slope is destabilised, failure is initiated. This study investigates the effect of clinoform progradation rates on failure size and frequency by conducting experiments over a range of water and sediment discharge rates. Neither failure size nor failure frequency changes with discharge rate; instead, increases in sediment supply are taken up by changes in the partitioning of sediment between the steep upper foreset and the more gradual delta-front apron (toeset) below. Sediment is delivered to the delta-front apron by a form of semi-continuous slow creep along the foreset. This slow creep is a failure mode that has not received sufficient attention in the submarine mass-flow literature. The independence of failure size and frequency from sediment supply rate suggests that the presence of mass-failure deposits does not provide information on the rate of sediment delivery. If these relations hold at field scales, this would imply that individual mass failures are relatively insensitive to changes in water and sediment supply.
Carrier Tracking Loop Performance in the Presence of Strong CW Interference

In a coherent data link, narrow-band radio frequency interference (RFI) near the carrier frequency can degrade the link performance by impacting the carrier tracking loop behavior and producing a partial or complete loss of coherence. If the RFI is strong enough, this effect can occur even though the frequency of the interference lies well beyond the carrier tracking loop bandwidth. In 1973, Bruno and Bianchard independently performed similar analyses of the response of a phase-locked loop (PLL) to a continuous wave (CW) interferor, and derived conditions under which the loop drops carrier lock and tracks the interference instead. This paper compares the contributions of these two analysts, and extends Bruno's closed form approximation for the loop phase error to the entire lock region.
Synthesis of azepino[3,4b]indoles via the Plancher rearrangement

Abstract The reaction of benzyl 3-formylpiperidine-1-carboxylate and aryl hydrazines under standard Fisher Indole conditions followed by reductive work-up affords azepino[3,4b]indoles in moderate to good yields. The products are proposed to be derived via a Plancher rearrangement [(a) Plancher, G. Gazz. Chim. Ital. 1898, 28, II, 374; (b) Plancher, G. Atti. Accad. Lincei 1900, 9, 5, 115; (c) Boyd-Barrett, H. S. J. Chem. Soc. 1932, 321].
Characterizing the Common Prior Assumption

Abstract Logical characterizations of the common prior assumption (CPA) are investigated. Two approaches are considered. The first is called frame distinguishability, and is similar in spirit to the approaches considered in the economics literature. Results similar to those obtained in the economics literature are proved here as well, namely, that we can distinguish finite spaces that satisfy the CPA from those that do not in terms of disagreements in expectation. However, it is shown that, for the language used here, no formulas can distinguish infinite spaces satisfying the CPA from those that do not. The second approach considered is that of finding a sound and complete axiomatization. Such an axiomatization is provided; again, the key axiom involves disagreements in expectation. The same axiom system is shown to be sound and complete both in the finite and the infinite case. Thus, the two approaches to characterizing the CPA behave quite differently in the case of infinite spaces. Journal of Economic Literature Classification Numbers: C70, D80.
SETI Institute as a model for managing interdisciplinary science

Abstract This paper addresses how the elements of the SETI Institute have come together across science, education, public outreach, media, policy, and societal issues, and where the Institute is going with this approach. SETI—and in particular, the SETI Institute—offers a noteworthy example for other interdisciplinary sciences to follow. The paper will provide the author's perspective on how this happened—what the driving factors were, and will be, for the SETI Institute.
A Comparison of Forecasting Accuracies of Alternative Regional Production Index Methodologies

This article examines the forecasting accuracies of various methods used by Federal Reserve Banks to estimate real value added by regional manufacturing industries. Using Texas manufacturing data and weighted forecasting accuracy measures consistent with index number construction for Texas, obtained results support the use of very simple methods based on the assumption of product exhaustion, allowing for technical change. More complex methods using Cobb-Douglas production functions estimated by Bayesian techniques did not perform as well, not because of lack of conceptual sophistication or appropriate prior information but probably because of the small number of observations and collinearity of the data that are available when constructing regional production indices. These results must be qualified. The weighted forecasting accuracy measures tend to obscure the fact that no one method is uniformly superior to the other methods for all industries. Given industry weights different from those for Texas, the...
p -Dirac Operators

We introduce non-linear Dirac operators in \({\mathbb{R}}^n\) associated to the p-harmonic equation and we extend to other contexts including spin manifolds and the sphere.
On Mostow rigidity for variable negative curvature

Abstract We prove a finiteness theorem for the class of complete finite-volume Riemannian manifolds with pinched negative sectional curvature, fixed fundamental group, and of dimension ⩾3. One of the key ingredients is that the fundamental group of such a manifold does not admit a small nontrival action on an R -tree.
Kinetic Monte Carlo study of activated states and correlated shear-transformation-zone activity during the deformation of an amorphous metal

Shear transformation zone (STZ) dynamics simulations, which are based on the kinetic Monte Carlo algorithm, are used to model the mechanical response of amorphous metals and provide insight into the collective aspects of the microscopic events underlying deformation. The present analysis details the activated states of STZs in such a model, as well as the statistics of their activation and how these are affected by imposed conditions of stress and temperature. The analysis sheds light on the spatial and temporal correlations between the individual STZ activations that lead to different macroscopic modes of deformation. Three basic STZ correlation behaviors are observed: uncorrelated activity, nearest-neighbor correlation, and self-reactivating STZs. These three behaviors correspond well with the macroscopic deformation modes of homogeneous flow, inhomogeneous deformation, and elastic behavior, respectively. The effect of pre-existing stresses in the simulation cell is also studied and found to have a homogenizing effect on STZ correlations, suppressing the tendency for localization.
Determination of true hook load and line tension under dynamic conditions

Theoretical and experimental studies show that true hook load depends on sheave friction, direction of block movement, and previous movement history. In some cases, actual hook load was observed to be up to 19% higher than the load predicted by the method currently used in the oil industry. The problem of determining true line tension from dead-line tension readings does not reside with the use of dead-line readings, but with how this information is used. Currently, the practice is to calculate hook load and line tension from the measured tension in the dead line, assuming static conditions. This practice also assumes that the tension in each line between the traveling and crown blocks and in the dead line is the same under static and dynamic conditions and will not change as block-movement direction changes. In addition, the current method accounts for sheave efficiency and block-movement direction only when calculating fast-line tension. The way in which the traveling-block-movement direction and sheave efficiency are used in the currently accepted prediction method implies that the entire friction loss is caused by the fast-line sheave. In reality, friction loss is caused by all the sheaves, not only the fast-line sheave. As a result, thismore » method will predict incorrect loads under dynamic conditions. Depending on the block-travel direction, this frictional loss could be either a help or a hindrance to the drawworks.« less
Hysteresis Offset in Stress Induced Polarization-Graded Ferroelectrics

Polarization-graded ferroelectrics and their electrically active counterparts, graded ferroelectric devices (GFDs) and transpacitors has been achieved in a number ways, including a variation in the composition of the material, or impressing a temperature gradients across the structure. In this article, we report how these same devices can be formed from homogeneous ferroelectric films of lead strontium titanate by imposing stress gradients on the materials normal to their electrode surfaces. A qualitative description of asymmetric hysteresis behavior based on a modified Landau potential is provided.
Four nucleon shell model calculations in a Faddeev - like approach

We use equations for Faddeev amplitudes to solve the shell-model problem for four nucleons in a model space that includes up to $14\ensuremath{\Elzxh}\ensuremath{\Omega}$ harmonic-oscillator excitations above the unperturbed ground state. Two- and three-body effective interactions derived from the Reid93 and Argonne V8' nucleon-nucleon potentials are used in the calculations. Binding energies, excitation energies, point-nucleon radii, and electromagnetic and strangeness charge form factors for ${}^{4}\mathrm{He}$ are studied. The structure of the Faddeev-like equations is discussed and a formula for the matrix elements of the permutation operators in a harmonic-oscillator basis is given. The dependence on harmonic-oscillator excitations allowed in the model space and on the harmonic-oscillator frequency is investigated. It is demonstrated that the use of three-body effective interactions improves the convergence of the results.
Simple Models for Turbulent Self-Regulation in Galaxy Disks

Supernova explosions and winds and energetic photon fluxes from young star clusters drive outflows and supersonic turbulence in the interstellar medium in galaxy disks and provide broad-spectrum heating, which generates a wide range of thermal phases in the gas. Star formation, the source of the energy inputs, is itself regulated by heating and phase exchanges in the gas. However, thermohydrodynamic self-regulation cannot be a strictly local process in the interstellar gas since galaxy disks also have a nearly universal structure on large scales. We propose that turbulent heating, wave pressure, and gas exchanges between different regions of disks play a dominant role in determining the preferred, quasi-equilibrium, self-similar states of gas disks on large scales. This paper presents simple families of analytic, thermohydrodynamic models for these global states, which include terms for turbulent pressure and Reynolds stresses. In these model disks, star formation rates, phase balances, and hydrodynamic forces are all tightly coupled and balanced. The models have stratified radial flows, with the cold gas slowly flowing inward in the midplane of the disk and with the warm/hot phases that surround the midplane flowing outward. The models suggest a number of results that are in accord with observations, as well as some novel predictions, including the following. (1) The large-scale gas-density and thermal-phase distributions in galaxy disks can be explained as the result of turbulent heating and spatial couplings. (2) The turbulent pressures and stresses that drive radial outflows in the warm gas above and below the disk midplane also allow a reduced circular velocity there. This effect was observed by Swaters, Sancisi, & van der Hulst in NGC 891, a particularly turbulent edge-on disk. The models predict that the effect should be universal in such disks. (3) Since dissipative processes generally depend on the square of the gas density, the heating and cooling balance in these models requires a star formation rate like that of the Schmidt law. Conversely, they suggest that the Schmidt law is the natural result of global thermohydrodynamical balance and may not obtain in disks far from equilibrium.
Optical receivers for wide band data transmission systems

Optical receiver designs for digital fiber data transmission systems operating with Gb/s data rates in the 800-1500-nm wavelength region have been investigated. The tradeoffs among conflicting receiver design requirements are considered in detail. The state-of-the-art performance of photodetectors and low noise amplifiers is discussed. Present receiver performance data, such as sensitivity, dynamic range, bit rate, and bit pattern dependencies, as a function of the bit rate in the 0.01-8 Gb/s data rate range are reviewed. The highest experimental sensitivities have been obtained with InGaAs APDs (avalanche photodiodes) and high-impedance GaAs FET (field-effect transistor) preamplifiers. >
The effect of substitution on protonation sites: evidence for protonation at N(3) in N(7)-substituted adenine

Abstract Several experimental and theoretical studies have shown that N (1) is the first site for protonation in adenine and N (9)-substituted adenine derivatives. N (7) is considered the site for the second protonation to yield dipositive cations. Results are reported here which indicate that this protonation pattern is altered in N (7)-substituted adenine derivatives. In particular, an X-ray diffraction analysis of the structure of 7-methyladenine dihydrochloride, [C 6 N 5 H 7 ]Cl 2 , definitively shows that the sites for protonation are N (3), as opposed to N (1), and N (9). Theoretical calculations of the molecular electrostatic potential in various systems suggest that such changes in preferred protonation sites should be expected, in general, when a modification of the molecular structure creates adjacent sites with similar reactivity, such as the N (3) and N (9) sites in 7-methyladenine.
First-row transition metal catalyzed reduction of carbonyl functionalities: a mechanistic perspective

The use of first-row transition metals for the catalytic reduction of carbonyl functionalities has become increasingly important in homogeneous catalysis. This Perspective examines the mechanistic aspects of these reduction reactions, with a focus on various interactions between metal complexes and substrates. Four different types of catalytic pathways, namely catalysis with dihydride (or dihydrogen) complexes, catalysis with monohydride complexes, metal–ligand bifunctional catalysis, and catalysis involving ionic mechanisms, are discussed with recent examples highlighted.
Cognitive processes in program comprehension

Abstract This paper reports on an empirical study of the cognitive processes involved in program comprehension. Verbal protocols were gathered from professional programmers as they were engaged in a program-understanding task. Based on analysis of these protocols, several types of interesting cognitive events were identified. These include asking questions and conjecturing facts about the code. We describe these event types and use them to derive a computational model of the programmers' mental processes.
Bargaining, Reputation, and Equilibrium Selection in Repeated Games with Contracts

Consider a two-person intertemporal bargaining problem in which players choose actions and offers each period, and collect payoffs (as a function of that period's actions) while bargaining proceeds. This can alternatively be viewed as an infinitely repeated game wherein players can offer one another enforceable contracts that govern play for the rest of the game. Theory is silent with regard to how the surplus is likely to be split, because a folk theorem applies. Perturbing such a game with a rich set of behavioral types for each player yields a specific asymptotic prediction for how the surplus will be divided, as the perturbation probabilities approach zero. Behavioral types may follow nonstationary strategies and respond to the opponent's play. In equilibrium, rational players initially choose a behavioral type to imitate and a war of attrition ensues. How much should a player try to get and how should she behave while waiting for the resolution of bargaining? In both respects she should build her strategy around the advice given by the “Nash bargaining with threats” (NBWT) theory developed for two-stage games. In any perfect Bayesian equilibrium, she can guarantee herself virtually her NBWT payoff by imitating a behavioral type with the following simple strategy: in every period, ask for (and accept nothing less than) that player's NBWT share and, while waiting for the other side to concede, take the action Nash recommends as a threat in his two-stage game. The results suggest that there are forces at work in some dynamic games that favor certain payoffs over all others. This is in stark contrast to the classic folk theorems, to the further folk theorems established for repeated games with two-sided reputational perturbations, and to the permissive results obtained in the literature on bargaining with payoffs as you go.
Exact Dirac-equation calculation of ionization induced by ultrarelativistic heavy ions

The time-dependent Dirac equation can be solved exactly for ionization induced by ultrarelativistic heavy-ion collisions. Ionization calculations are carried out in such a framework for a number of representative ion-ion pairs. For each ion-ion pair, the computed cross section consists of two terms: a constant energy independent term and a term whose coefficient is ln {gamma}. Scaled values of both terms are found to decrease with increasing Z of the nucleus that is ionized. (c) 2000 The American Physical Society.
Reconstructing the Cosmic Evolution of the Chemical Elements

The chemical elements are created in nuclear fusion processes in the hot and dense cores of stars. The energy generated through nucleosynthesis allows stars to shine for billions of years. When these stars explode as massive supernovae, the newly made elements are expelled, chemically enriching the surrounding regions. Subsequent generations of stars are formed from gas that is slightly more element-enriched than that from which previous stars formed. This chemical evolution can be traced back to its beginning soon after the Big Bang by studying the oldest and most metal-poor stars still observable in the Milky Way today. Through chemical analysis, they provide the only available tool for gaining information about the nature of the short-lived first stars and their supernova explosions more than thirteen billion years ago. These events set in motion the transformation of the pristine universe into a rich cosmos of chemically diverse planets, stars, and galaxies.
HIRIS — Eos instrument with high spectral and spatial resolution☆

Abstract The High-Resolution Imaging Spectrometer (HIRIS) is a JPL-facility instrument designed for NASA's Earth Observing System (Eos). It will have 10-nm wide spectral bands from 0.4 to 2.5 μm at 30-m spatial resolution over a 24-km swath. The spectral resolution allows identification of many minerals in rocks and soils, important algal pigments in oceans and inland waters, spectral changes associated with plant canopy biochemistry, composition of atmospheric aerosols, and grain size of snow and its contamination by absorbing impurities. The bands will have 12-bit quantization over a dynamic range suitable for bright targets, such as snow. For targets of low brightness, such as water bodies, image-motion compensation will allow gains up to a factor of 8 to increase signal-to-noise ratios. The sensor will be able to point ±26° crosstrack and +52°/−30° downtrack. In the 705-km orbit altitude proposed for Eos, the crosstrack pointing capability will allow 3–4 views during a 16-day revisit cycle.
Display techniques for interactive text manipulation

The Augmentation Research Center (ARC) at the Stanford Research Institute (SRI), has been developing for several years a computer-based on-line system called NLS. NLS is part of ARC's research on enhancing the intellectual effectiveness of people. Central to the developments to date is highly interactive text manipulation using chiefly display terminals. The NLS system supports a range of display terminals (from expensive text/graphics displays to inexpensive Alpha Numeric displays) and typewriter terminals. The NLS program runs as a subsystem within a TENEX time-sharing system on a DEC PDP-10 computer.
Transience of second-class particles and diffusive bounds for additive functionals in one-dimensional asymmetric exclusion processes

Consider a one-dimensional exclusion process with finite-range translation-invariant jump rates with nonzero drift. Let the process be stationary with product Bernoulli invariant distribution at density ρ. Place a second-class particle initially at the origin. For the case ρ≠1/2 we show that the time spent by the second-class particle at the origin has finite expectation. This strong transience is then used to prove that variances of additive functionals of local mean-zero functions are diffusive when ρ≠1/2. As a corollary to previous work, we deduce the invariance principle for these functionals. The main arguments are comparisons of H−1 norms, a large deviation estimate for second-class particles and a relation between occupation times of second-class particles, and additive functional variances.
Measuring designer performance to verify design automation systems

Design automation at the register transfer level of design is still in its infancy, and it is not yet completely understood what the appropriate measures used in direction the automated design process should be. To establish these measures, results of these design automation systems must be compared with some near optimal designs. A set of statistically based experiments is developed to estimate near optimal designs. A method is demonstrated for gathering data on designer performance, specifically at the different levels of systems design, and in general for calibration of other design automation systems where the intuitive designer still performs more capably than the present design algorithms. An analysis of variance is used to indicate the relative importance of various decisions in a system design. It is shown that the algorithm to be implemented and the hardware design style account for 90 percent of the variation in the results. Thus, selecting the design style (e.g., distributed, microprocessor, pipelined, etc.) is the most important parameter for a design automation system.
A Cubic Micron of Equilibrium Pair Plasma

Is it possible to create a small volume of equilibrium pair plasma in the laboratory with an intense laser pulse? No. The required power would exceed 1018 W. The number of seed particles required to absorb the laser energy would approach the number of pairs in the desired plasma, and their radiation in a visible laser field would occur at excessively high frequencies.
HYPERTHYROIDISM IN A PATIENT WITH POSTPARTUM NECROSIS OF THE PITUITARY: CASE REPORT AND IMPLICATIONS

A patient with postpartum necrosis of the pituitary is presented, who exhibited evidence of panhypopituitarism for fifteen years following uterine hemorrhage. Three years after initiation of therapy with cortisone and desiccated thyroid, and eighteen years post partum, thyrotoxicosis developed. Active hypcrthyroidism persisted, but there was continued evidence of pituitary insufficiency with respect to secretion of gonadotropic, thyrotropic, and adrenocorticotropic hormones. The evidence suggests that excessive secretion of pituitary thyrotropic hormone was not the cause of the hyperthyroidism of Graves’ disease in this patient.
Modeling Dynamic Groups for Agent-Based Pedestrian Crowd Simulations

Group modeling is still an open challenge problem in pedestrian crowd simulations. Most existing work is based on socio-psychological models which can only describe the dynamics of pedestrians’ socio-psychological states. The ability of dynamic grouping also requires that pedestrians are intelligent to behave adaptively in the ever changing environment. However, little work has incorporated the effect of artificial intelligence in the study of group behaviors. This paper describes a novel model to simulate dynamic groups based on both utility theory and social comparison theory. To our knowledge, the model is one of few models using utility theory and social comparison theory to model group behaviors. Experiment results suggest that groups can be dynamically formed and grouping has significant effect on crowd behaviors. Besides, the model can also be used to simulate various structures in dynamic groups.
Interest Rates and the Net Deficit of All Government Levels Combined: An Empirical Note

This empirical note studies the impact of the net budget deficits of all levels of government in the U.S. combined on ten-year Treasury notes for the study period 1955-1984. It is found that this total net budget deficit acted to elevate the yield on ten-year Treasury notes.
Formal synthesis of teleocidin a via indole-Cr(CO)3 complexes

Abstract The addition of a cyano-stabilized anion to a 4-aminoindole-Cr(CO) 3 complex can be directed to selective C-7 substitution, and the resulting intermediate is part of a formal total synthesis of teleocidin A1/A2.
The Mahler measure of parametrizable polynomials

Abstract Our aim is to explain instances in which the value of the logarithmic Mahler measure m ( P ) of a polynomial P ∈ Z [ x , y ] can be written in an unexpectedly neat manner. To this end we examine polynomials defining rational curves, which allows their zero-locus to be parametrized via x = f ( t ) , y = g ( t ) for f , g ∈ C ( t ) . As an illustration of this phenomenon, we prove the equality π m ( y 2 + y ( x + 1 ) + x 2 + x + 1 ) = 2 D ( i ) − 3 4 D ( ω ) , where ω = e 2 π i / 3 and D ( z ) is the Bloch–Wigner dilogarithm. As we shall see, formulas of this sort are a consequence of the Galois descent property for Bloch groups. This principle enables one to explain why the arguments of the dilogarithm function depend only on the points where the rational curve defined by P intersects the torus | x | = | y | = 1 . In the process we also present a general method for computing the Mahler measure of any such polynomial.
Fatal erythroblastosis fetalis due to anti-Kell isoimmune disease

case descr ibed here, can only be detected by procedures such as the M T T cytochemica l method , which are too expens ive and t ime consuming for rout ine use. However, w h e n e v e r unexpla ined neonata l j aund ice occurs, particularly in e thnic groups such as the Greeks or Chinese in w h o m severe G-6 -PD deficiency is prevalent, identification of G-6-PD deficiency in the neonate may alert family and physic ian to the need for avoidance of potentially hemolyt ic agents during subsequen t pregnancies. The ery throcytes o f such newborn infants should, therefore , be eva lua ted routinely for the presence of G-6-PD deficiency.
High Energy Photon-Photon and Electron-Photon Collisions

The advent of a next linear e±e- collider and back-scatterd laser beams will allow the study of a vast array of high energy processes of the Standard Model through the fusion of real and virtual photons and other gauge bosons. As examples, I discuss virtual photon scattering γ*γ*→X in the region dominated by BFKL hard Pomeron exchange and report the predicted cross sections at present and future e±e- colliders. I also discuss exclusive γγ reactions in QCD as a measure of hadron distribution amplitudes and a new method for measuring the anomalous magnetic and quadrupole moments of the W and Z gauge bosons to high precision in polarized electron-photon collisions.
RADIATION EFFECTS IN SOLIDS

The theory of radiation effects in solids is summarized, and the various phenomena are illustrated with examples. The effects produced by radiation are electronic excitation, elastic collisions, displacements, inelastic collisions, and transmutations. The eIfects on alkali halides, alpha brass, semiconductors, graphite, and uranium are specifically discussed. (J.S.R.)
Numerical prediction of MODUs drift during Hurricane Katrina

Severe hurricanes, such as Katrina, broke the mooring lines of a number of mobile offshore drilling units (MODU) deployed in the Gulf of Mexico and some of those MODUs went adrift. A drifting MODU may damage other critical elements of the offshore oil and gas infrastructure by colliding with floating or fixed production systems and transportation hubs, or by rupturing pipelines owing to their dragging anchors over the seabed. To avoid or mitigate the damage caused by a drifting MODU, it is desirable to understand the mechanics of the drift of a MODU under the impact of severe wind, wave and current and have the capability of predicting the trajectory of the drift. To explore the feasibility and accuracy of predicting the trajectory of a drifting MODU based on hindcast met-ocean conditions and limited knowledge of the condition of the drifting MODU, this study employed a simplified equation describing only the horizontal (surge, sway and yaw) motions of a MODU under the impact of steady wind, current and wave forces. The simplified hydrodynamic model neglects the first- and second-order oscillatory wave forces, unsteady wind forces (owing to wind gustiness), wave drift damping, and the effects of the body oscillation on the steady wind and current forces. It was assumed that the net effects of the oscillatory forces on the steady motion are insignificant. To verify the accuracy and feasibility of our simplified approach, the predicted drifting trajectories of two MODUs were compared with the corresponding measurements recorded by the global positioning system (GPS).
The chiral potts model and its associated link invariant

A new link invariant is derived using the exactly solvable chiral Potts model and a generalized Gaussian summation identity. Starting from a general formulation of link invariants using edge-interaction spin models, we establish the uniqueness of the invariant for self-dual models. We next apply the formulation to the self-dual chiral Potts model, and obtain a link invariant in the form of a lattice sum defined by a matrix associated with the link diagram. A generalized Gaussian summation identity is then used to carry out this lattice sum, enabling us to cast the invariant into a tractable form. The resulting expression for the link invariant is characterized by roots of unity and does not appear to belong to the usual quantum group family of invariants. A table of invariants for links with up to eight crossings is given.
Reorientational tunneling and elastic-dipole properties of OH - and OD - molecular defects in alkali fluorides

A microscopic model of ${\mathrm{OH}}^{\mathrm{\ensuremath{-}}}$ and ${\mathrm{OD}}^{\mathrm{\ensuremath{-}}}$ molecular defects and their reorientational tunneling has been determined in alkali fluoride crystals, using high-resolution Fourier transform infrared studies of their stretching mode absorptions. In LiF, NaF, and KF hosts, the measured integrated stress dichroisms yield symmetries and values of their elastic dipoles, which are found to be ``disk-shaped'' $〈111〉$ oriented tensors aligning with a Curie law parallel to an applied $〈111〉$ stress. Analyses of the spectral band shapes and their changes under stress alignment and $T$ variation allow us to estimate their tunneling splittings $\ensuremath{\Delta}$ and vibrational lifetimes $\ensuremath{\tau}$. This is best detectable in LiF:${\mathrm{OH}}^{\mathrm{\ensuremath{-}}}$, for which the separation and width of two well-resolved Lorentzian bands at 2--20 K yield $\ensuremath{\Delta}=1.2$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ and $\ensuremath{\tau}\ensuremath{\approx}9$ ps. Isotope variation $\mathrm{H}\ensuremath{\rightarrow}\mathrm{D}$ reduces strongly the tunneling splitting by at least a factor of 6 in LiF and NaF. A general model for $〈111〉$ oriented elastic dipole disks with $70\ifmmode^\circ\else\textdegree\fi{}$ tunneling between nearest neighbor orientations is derived which may become valid for ${\mathrm{OH}}^{\mathrm{\ensuremath{-}}}{/\mathrm{O}\mathrm{D}}^{\mathrm{\ensuremath{-}}}$ in all five alkali fluorides.
Two-step synthesis of carbohydrates by selective aldol reactions.

Studies of carbohydrates have been hampered by the lack of chemical strategies for the expeditious construction and coupling of differentially protected monosaccharides. Here, a synthetic route based on aldol coupling of three aldehydes is presented for the de novo production of polyol differentiated hexoses in only two chemical steps. The dimerization of α-oxyaldehydes, catalyzed by l-proline, is then followed by a tandem Mukaiyama aldol addition-cyclization step catalyzed by a Lewis acid. Differentially protected glucose, allose, and mannose stereoisomers can each be selected, in high yield and stereochemical purity, simply by changing the solvent and Lewis acid used. The reaction sequence also efficiently produces ^(13)C-labeled analogs, as well as structural variants such as 2-amino– and 2-thio–substituted derivatives.
SketchREAD: a multi-domain sketch recognition engine

We present SketchREAD, a multi-domain sketch recognition engine capable of recognizing freely hand-drawn diagrammatic sketches. Current computer sketch recognition systems are difficult to construct, and either are fragile or accomplish robustness by severely limiting the designer's drawing freedom. Our system can be applied to a variety of domains by providing structural descriptions of the shapes in that domain; no training data or programming is necessary. Robustness to the ambiguity and uncertainty inherent in complex, freely-drawn sketches is achieved through the use of context. The system uses context to guide the search for possible interpretations and uses a novel form of dynamically constructed Bayesian networks to evaluate these interpretations. This process allows the system to recover from low-level recognition errors (e.g., a line misclassified as an arc) that would otherwise result in domain level recognition errors. We evaluated SketchREAD on real sketches in two domains---family trees and circuit diagrams---and found that in both domains the use of context to reclassify low-level shapes significantly reduced recognition error over a baseline system that did not reinterpret low-level classifications. We also discuss the system's potential role in sketch-based user interfaces.
FLAVOR-SPIN SYMMETRY AND THE TENSOR CHARGE

Exploiting an approximate phenomenological symmetry of the JPC = 1+- light axial vector mesons and using pole dominance, we calculate the flavor contributions to the nucleon tensor charge. The result depends on the decay constants of the axial vector mesons and their couplings to the nucleons.
Inclusion body myositis.

Purpose of reviewSporadic inclusion body myositis (sIBM) is a poorly understood immune and degenerative disease of skeletal muscle. Here, current opinion of the nature of this disease is summarized.Recent findingsRecent findings for sIBM include further characterization of muscle involvement through
Scheduling independent tasks to reduce mean finishing time

Sequencing to minimize mean finishing time (or mean time in system) is not only desirable to the user, but it also tends to minimize at each point in time the storage required to hold incomplete tasks. In this paper a deterministic model of independent tasks is introduced and new results are derived which extend and generalize the algorithms known for minimizing mean finishing time. In addition to presenting and analyzing new algorithms it is shown that the most general mean-finishing-time problem for independent tasks is polynomial complete, and hence unlikely to admit of a non-enumerative solution.
Synthesis and antimalarial activity of heteroatom-containing bicyclic endoperoxides

Abstract Mechanism-based design and short syntheses involving novel Tebbe methylenations of a-heteroatom-substituted ketones led to preparation of heteroatom-containing bicyclic endoperoxides 4-6. The crucial final photo-oxygenative cyclization step succeeded only when the intermediate 1,6-dienes carried anisyl but not phenyl substituents. Distinguishing between endoperoxide and cyclobutane cyclization products was achieved reliably by 13C NMR spectroscopy. Antimalarial testing of endoperoxides 4-6 in vitro showed them to have only weak activities (IC50 = 500-1100nM). Ferrous bromide-induced reductions of sulfonamide endoperoxides 4, although forming the expected hydroxylated ether and ring-contracted products 7 and 8, caused virtually no rearrangement of hexamethyl Dewar benzene; therefore, the intermediacy of any oxidatively damaging hich-valent iron-oxo intermediate appears unlikely.
Laboratory automation via a VM/370 teleprocessing virtual machine

A mechanism called the Teleprocessing Virtual Machine (TPVM) has been designed to provide remote intelligent sub-systems with the ability to access and utilize the power of the IBM VM/370 environment. This paper describes the TPVM implementation and operation in a laboratory environment at the Yorktown Research Center. However, the TPVM mechanism is applicable to a much broader spectrum of usage.
An Examination of Cross‐Sectional Realized Stock Returns using a Varying‐Risk Beta Model

Using the dual-beta model of Bhardwaj and Brooks (1993), this study examines the cross-section of realized stock returns. Bull-market betas are significantly positively related to returns and, except for some models in January, bear-market betas are significantly negatively related to returns. These relationships are not lost even after other independent variables, including size, book-to-market equity, and an earnings-price ratio, are added to the cross-sectional regressions. Book-to-market equity is an important factor in bear, but not bull, markets. Size is important in January and in bear markets during February through December.
Control principles in flexible manufacturing

Abstract Flexible manufacturing systems present a setting in which application of control concepts can be crucial. Today, some concepts are in place where needed, some are waiting to be applied, and some are yet to be created. This paper is a status report on FMS control technology, based on ongoing work at the The Charles Stark Draper Laboratory in the development of decision support systems for FMSs.
Phase relaxation of electrons in disordered conductors

Abstract Conduction electrons in disordered metals and heavily doped semiconductors at low temperatures preserve their phase coherence for a long time: phase relaxation time τ ϕ can be orders of magnitude longer than the momentum relaxation time. The large difference in these time scales gives rise to well-known effects of weak localization, such as anomalous magnetoresistance. Among other interesting characteristics, study of these effects provide quantitative information on the dephasing rate 1/ τ ϕ . This parameter is of fundamental interest: the relation between ℏ/ τ ϕ and the temperature T (a typical energy scale of an electron) determines how well a single electron state is defined. We will discuss the basic physical meaning of 1/ τ ϕ in different situations and its difference from the energy relaxation rate. At low temperatures, the phase relaxation rate is governed by collisions between electrons. We will review existing theories of dephasing by these collisions or (which is the same) by electric noise inside the sample. We also discuss recent experiments on the magnetoresistance of 1 D systems: some of them show saturation of 1/ τ ϕ at low temperatures, the other do not. To resolve this contradiction we discuss dephasing by an external microwave field and by nonequilibrium electric noise.
Determining Sets, Resolving Sets, and the Exchange Property

A subset U of vertices of a graph G is called a determining set if every automorphism of G is uniquely determined by its action on the vertices of U. A subset W is called a resolving set if every vertex in G is uniquely determined by its distances to the vertices of W. Determining (resolving) sets are said to have the exchange property in G if whenever S and R are minimal determining (resolving) sets for G and $${r\in R}$$, then there exists $${s\in S}$$so that $${S-\{s\} \cup \{r\}}$$is a minimal determining (resolving) set. This work examines graph families in which these sets do, or do not, have the exchange property. This paper shows that neither determining sets nor resolving sets have the exchange property in all graphs, but that both have the exchange property in trees. It also gives an infinite graph family (n-wheels where n ≥ 8) in which determining sets have the exchange property but resolving sets do not. Further, this paper provides necessary and sufficient conditions for determining sets to have the exchange property in an outerplanar graph.
Viperin: A Multifunctional, Interferon-Inducible Protein that Regulates Virus Replication

Viperin is an interferon-inducible protein that inhibits the replication of a variety of viruses by apparently diverse mechanisms. In some circumstances, it also plays a role in intracellular signaling pathways. Its expression in mitochondria, revealed by infection with human cytomegalovirus, also affects cellular metabolic pathways. We review here the current status of our understanding of this unusual molecule.
Management misinformation systems

“Most management information systems are designed on the assumption that the critical deficiency under which most managers operate is lack of relevant information. I do not deny that most managers lack a good deal of information that they should have, but I do deny that this is the most important informational deficiency from which they suffer. It seems to me that they suffer more from an over abundance of irrelevant information.”
What's in a domain: understanding how students approach questioning in history and science

How students ask questions as they learn has implications for understanding, retention, and problem solving. The current research investigates the influence of domain, age, and previous experience with content on the ways students approach questioning across history and science texts. In 3 experiments, 3rd-, 8th-, and 10th-grade students in large urban schools in the Northeast United States were asked to read history and science passages and generate questions whose answers would help them improve their understanding. Results indicate a persistent main effect of domain on questions asked across studies. Students generated significantly more questions regarding the purpose or function of ideas in science passages and generated significantly more questions requesting supplemental information across history passages. Implications for instructional design and classroom instruction will be discussed.
High-resolution mass spectrometry.

Mass Spectrometry is unique in the type and amount of information that it can often supply on submicrogram samples. Recent advances include improved understanding of the basic factors affecting ion reaction rates, and application of these in metastable and collision-induced decompositions. Utilization of the unusual quantity of information in a high-resolution spectrum is greatly facilitated with on-line computers; identification and interpretation of spectra by computer techniques is faster and often more informative than the human counterpart. Feedback control from the computer makes possible the multiple rescanning of peaks in blank spectral regions, increasing signal quality and quantity dramatically. It appears that the application of a combination of these techniques of high-resolution mass spectrometry will give detailed amino acid sequence information on mixtures of peptides.
Physical Conditions in the Narrow-Line Region of Markarian 3. I. Observational Results

We use Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) long-slit low-resolution spectroscopy from 1150 to 10300 A to study the physical conditions in the narrow-line region (NLR) of the Seyfert 2 galaxy Markarian 3. We find from the He II λ1640/λ4686 line ratio and the Balmer decrement that the extinction within Mrk 3 along the line of sight to the NLR is best characterized by an LMC-type extinction curve. We observe an extinction gradient increasing from west to east along the STIS slit (at position angle 71° measured east from north) in both line and continuum emission. We infer from this gradient that the host galaxy disk is tilted toward the observer in the east: the line of sight to the eastern emission-line cone intersects more dust in the plane of the galaxy than that to the western cone. From emission-line diagnostics we find that the NLR gas is photoionized by the hidden active galactic nucleus continuum and that its density decreases with increasing distance from the center. We model the observed continuum as a combination of reddened host galaxy light from an old stellar population, reddened H+ and He+2 recombination continua, and less reddened scattered light from the central engine with spectral index α = 1 (Lν ∝ ν-α). The host galaxy-to-scattered light ratio is estimated to be 3 : 1 at 8125 A in a 01 × 18 aperture. Using a two-component power-law model for the ionizing continuum (α = 2 for 13.6 eV < E < 0.2 keV and α = 1 for 0.2 keV < E < 50 keV), we find that the covering factor (normalized for our observation aperture) of the NLR gas is greater than 0.7%. We estimate that the amount of intrinsic nonionizing UV continuum scattered into our line of sight is 0.04%. This is consistent with our estimate of the scattering fraction for broad C IV λλ1548, 1551 emission.
An in situ tunneling microscopic study of polycrystalline aluminum in sodium hydroxide solution

Abstract Scanning Tunneling Microscopy has been used to study polycrystalline aluminum in sodium hydroxide solution. The effect of oxidation and reduction processes on the electrode surface has been studied in-situ. The initiation of oxide formation appears to start in the form of patches or clusters. In the study of the oxide formation by STM, a passive to active region was detected at −1.05 V vs. SHE in 0.01 M NaOH.
Colloidal Particles Coated and Stabilized by DNA-Wrapped Carbon Nanotubes

Single-walled carbon nanotubes (SWNTs) are dispersed in water via wrapping with short segments of single-stranded DNA (ssDNA). Small angle neutron scattering suggests a power-law exponent that is consistent with clustered nanotubes and hence marginal stability. The SWNT-ssDNA complex is used to stabilize dispersions of hydrophilic colloidal particles with the nanotubes adhered to the surface of the colloids. Near-infrared fluorescence microscopy demonstrates the interfacial band-gap fluorescence of these SWNT-coated particles, suggesting potential routes to novel platforms and applications.