cssi/SciSciGPT-SciSciNet huggingface dataset:
Photonic applications of bacteriorhodopsin

The photochromic protein bR is receiving much attention as an interesting alternative to conventional inorganic semiconductor based materials for a variety of applications in optical recording and information processing. Recent advances in genetic engineering techniques for tailoring molecular properties without degrading of its inherent mechanical and thermal stability make it an outstanding photonic material. Some of the photonic applications already demonstrated by our group are reviewed. We exploit the parallel processing of optics and the real-time nature of bR films for the implementation of several photonic applications. We reported a convenient method to obtain all-optical light modulation in bacteriorhodopsin films using a degenerate four-wave mixing geometry. Chemically stabilized films of bacteriorhodopsin in a polymer matrix for which the life time of the excited M state is tens of seconds are used to demonstrate all-optical light intensity modulation. Small intensities of order mW/cm2 are used in the modulation experiments. The fast photochemical transition from M to B permits reasonably fast modulation speeds independent of the slow thermal M to B relaxation time. The experimental system can also be viewed as an all-optical switch, that uses molecular states in a bacteriorhodopsin thin film, where a low power blue pulse turns on a signal red beam. All-optical logic gates are implemented with wild- type and chemically stabilized films of bacteriorhodopsin using a two-color backward degenerate four- wave mixing geometry. The sensitivity of each bR film is markedly different due to the large differences in the saturation intensity. Red light is used to form a grating due to the B to M transition and blue light is used to form a grating due to the fast photochemical transition from M to B. Each of the two wavelengths in the experimental system acts as an input to the all-optical gate and the phase conjugate signal beam bears the output of the gate. To establish the origin of the nonlinearity we studied the intensity dependence of the self-focusing and self-defocusing properties of wild-type bR in water solution using the Z-scan technique with low power cw lasers at two wavelengths on either side of the absorption band. Our measurements indicate that the sign of the nonlinearity depends on the wavelength and the magnitude depends on the fluence of the incident laser beam. The observed self-defocusing and focusing is not due to the intrinsic electronic nonlinearity. The observations can be explained in terms of the Kramers-Kronig dispersion relation that relates the real and imaginary parts of the complex index of refraction to the absorption spectrum.We developed an optical pattern recognition system using Optical Fourier Transform with bR films. The photoinduced dichroism and its dependence on light intensity allows one to use the bR film as a real-time self-adaptive spatial filter at the FT plane. We also demonstrate flow disturbance visualization and beam shaping.
DESIGN OF AEROGRAVITY-ASSIST TRAJECTORIES

Aero-gravity assist (AGA) trajectories are optimized in the sense of maximizing AV obtained by the fly by, maximizing aphelion, minimizing perihelion, and minimizing the time of flight (TOF) for a particular destination planet. A graphical method based on Tisserand's criterion is introduced to identify potential AGA trajectories. To demonstrate the application of the theory, patched-conic AGA trajectories are computed to each planet in the Solar System. For an L/D of 7, and a launch VQO of 6.0 km/s, Pluto may be reached in 5.5 years using a Venus-Mars-Venus AGA.
Redundancy effects in the processing of emotional faces

How does the visual system represent the ensemble statistics of visual objects? This question has received intense interest in vision research, yet most studies have focused on the extraction of mean statistics rather than its dispersion. This study focuses on another aspect of ensemble statistics: the redundancy of the sample. In two experiments, participants were faster judging the facial expression and gender of multiple faces than a single face. The redundancy gain was equivalent for multiple identical faces and for multiple faces of different identities. To test whether the redundancy gain was due to increased strength in perceptual representation, we measured the magnitude of facial expression aftereffects. The aftereffects were equivalent when induced by a single face and by four identical faces, ruling out increased perceptual strength as an explanation for the redundancy gain. We conclude that redundant faces facilitate perception by enhancing the robustness of representation of each face.
Glass-, Boron-, and Graphite-Filament-Wound Resin Composites and Liners for Cryogenic Pressure Vessels.

Tensile and interlaminar shear strengths of glass, boron, and graphite filament wound resin composites and liners for cryogenic pressure vessels
A multi-period equilibrium pricing model of weather derivatives

The prevalence of commercial activities whose profit and cost are correlated with weather risk makes weather derivatives valuable financial instruments that enable hedging of price or volumetric (quantity) risk in many industries. This paper proposes a multi-period equilibrium pricing model for weather derivative. In our stylized economy representative agents of weather-sensitive industries optimizes their hedging portfolios that drive the supply and demand for weather derivative which are dynamically determined based on a utility indifference pricing framework. At equilibrium the weather derivative market will be cleared and their market price can be obtained. Numerical examples illustrate the equilibrium prices and optimal choices for the weather derivative as function of the correlation between weather indices and demand for the underlying commodity. We also demonstrate the benefit of multiple trading opportunities which allows rebalancing of the hedging portfolio prior to the commodity delivery date, as compared to a single shot framework.
Precovering and Preenveloping Ideals

In [8] L. Salce introduced the notion of a cotorsion pair (ℱ, &#x1d49e;) in the category of abelian groups. But his definitions and basic results carry over to more general abelian categories and have proven to be useful in a variety of settings. A significant result of cotorsion theory proven by Eklof and Trlifaj is that if a pair (ℱ, &#x1d49e;) of classes of R-modules is cogenerated by a set, then it is complete [1]. Recently Fu, Herzog, Guil, and Torrecillas developed the ideal approximation theory [6], [4]. In this article we look at a result motivated by the Eklof and Trlifaj argument for an ideal ℐ when it is generated by a set of homomorphisms.
RADIAL VELOCITIES OF GALACTIC O-TYPE STARS. II. SINGLE-LINED SPECTROSCOPIC BINARIES

We report on new radial velocity measurements of massive stars that are either suspected binaries or lacking prior observations. This is part of a survey to identify and characterize spectroscopic binaries among O-type stars with the goal of comparing the binary fraction of field and runaway stars with those in clusters and associations. We present orbits for HDE 308813, HD 152147, HD 164536, BD–16°4826, and HDE 229232, Galactic O-type stars exhibiting single-lined spectroscopic variation. By fitting model spectra to our observed spectra, we obtain estimates for effective temperature, surface gravity, and rotational velocity. We compute orbital periods and velocity semiamplitudes for each system and note the lack of photometric variation for any system. These binaries probably appear single-lined because the companions are faint and because their orbital Doppler shifts are small compared to the width of the rotationally broadened lines of the primary.
The Heavy Quark Masses from Quarkonia

We report on the status of the determination of the heavy quark masses from our calculation of the quarkonia spectra. All sources of systematic errors that enter the quark mass determination are accounted for. We explicitly keep ma ≠ 0 in the perturbative calculation relating the bare lattice mass to a renormalized mass. Our results are still preliminary.
Seven years of observations of mid-tropospheric CO2 from the Atmospheric Infrared Sounder

Abstract The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7–15.4 μm spectral region with spectral resolving power of better than 1200. The AIRS was designed to measure temperature and water vapor profiles and cloud properties for improvement in weather forecast and improved parameterization of climate processes. Currently a subset of AIRS Level 1B Radiance Products is assimilated by NWP centers, resulting in significant forecast improvement. Scientists have also demonstrated accurate retrievals of minor gases from AIRS including carbon monoxide, methane, and ozone. The excellent sensitivity and stability of the AIRS instrument has recently allowed the AIRS team to successfully retrieve carbon dioxide (CO 2 ) concentrations in the mid-troposphere (8–10 km) with a horizontal resolution of 100 km and accuracy better than 2 ppm. The AIRS mid-tropospheric CO 2 yield is 15,000 measurements per 24-h period over land and ocean, day and night for clear and cloudy scenes. The AIRS CO 2 accuracy has been validated against a variety of mid-tropospheric aircraft measurements as well as upward looking interferometers. Findings from the AIRS data include higher than expected variability in the mid-troposphere, the presence of a seasonally variable belt of enhanced CO 2 in the southern hemisphere, and observations of impact of atmospheric dynamics on the CO 2 concentrations in the mid-troposphere including the effects of El Nino/La Nina and the Arctic polar vortex. The full mid-tropospheric AIRS CO 2 data set is now available at the NASA GES/DISC for the 8 year time span since AIRS became operational.
The First General Palladium Catalyst for the Suzuki−Miyaura and Carbonyl Enolate Coupling of Aryl Arenesulfonates

The first general method for the palladium-catalyzed Suzuki−Miyaura and carbonyl enolate coupling of unactivated aryl arenesulfonates was developed utilizing XPhos, 1, and Pd(OAc)2. This is of significant interest because aryl tosylates and aryl benzenesulfonates are more easily handled and considerably less expensive than aryl triflates. This catalyst system effects the coupling of a variety of aryl, heteroaryl, and extremely hindered arylboronic acids with different aryl tosylates, under mild conditions. The same catalyst was employed in the first carbonyl enolate coupling of aryl arensulfonates.
The Berry paradox

Lecture given Wednesday 27 October 1993 at a Physics -- Computer Science Colloquium at the University of New Mexico. The lecture was videotaped; this is an edited transcript. It also incorporates remarks made at the Limits to Scientific Knowledge meeting held at the Santa Fe Institute 24--26 May 1994.
KrF laser-induced OH fluorescence imaging in a supersonic combustion tunnel

Planar fluorescence images of OH in a continuous-flow, electrical-resistively heated, high enthalpy, hydrogen-air combustion tunnel, induced by a tunable KrF laser, were recorded. These images were compared to previously recorded fluorescence images induced by a doubled-dye laser under similar conditions. Images induced by the doubled-dye laser system demonstrated a severe distortion caused by absorption and fluorescence trapping. By contrast, images of the fluorescence induced by the tunable KrF laser retained the symmetry properties of the flow. Based on signal-to-noise ratio measurements the yield of the fluorescence induced by the doubled-dye laser is larger than the fluorescence yield induced by the KrF laser. The measurements in the present facility of OH fluorescence induced by the KrF laser were limited by the photon-statistical noise. Based 2 on this result, doubled-dye laser systems are recommended for OH imaging in small and OH lean (less than 10 exp 15/cu cm) facilities. KrF lasers should be selected otherwise.
Structured Lattice Codes for Some Two-User Gaussian Networks With Cognition, Coordination, and Two Hops

We study a number of two-user interference networks with multiple-antenna transmitters/receivers (MIMO), transmitter side information in the form of linear combinations (over an appropriate finite-field) of the information messages, and two-hop relaying. We start with a cognitive interference channel (CIC) where one of the transmitters (noncognitive) has knowledge of a rank-1 linear combination of the two information messages, while the other transmitter (cognitive) has access to a rank-2 linear combination of the same messages. This is referred to as the network-coded CIC, since such linear combination may be the consequence of some random linear network coding scheme implemented in the backbone wired network. For such channel we develop an achievable region based on a few novel concepts: precoded compute-and-forward (PCoF) with channel integer alignment (CIA), combined with standard dirty-paper coding. We also develop a capacity region outer bound and find the symmetric generalized degrees of freedom (GDoF) region of the network-coded CIC. Through the GDoF characterization, we show that knowing mixed data (linear combinations of the information messages) provides a unbounded spectral efficiency gain over the classical CIC counterpart, if the ratio (in decibel) of signal-to-noise (SNR) to interference-to-noise is larger than certain threshold. Then, we consider a Gaussian relay network having the two-user MIMO IC as the main building block. We use PCoF with CIA to convert the MIMO IC into a deterministic finite-field IC. Then, we use a linear precoding scheme over the finite-field to eliminate interference in the finite-field domain. Using this unified approach, we derive the symmetric sum rate of the two-user MIMO IC with coordination, cognition, and two-hops. We also provide finite-SNR results (not just DoF) which show that the proposed coding schemes are competitive against state-of-the-art interference avoidance scheme based on orthogonal access, for standard randomly generated Rayleigh fading channels.
Search for promethium-like gold lines and other transitions of interest to fusion research☆

Abstract EUV spectra in the range λ = 13−40 nm were measured for foil-excited gold ions at 31–238 MeV. Data were recorded at the higher energies to extend and to complement previous measurements and at the lowest energy to see if the recently predicted 5s–5p resonance lines in the Pm-like ion, Au XIX, could be seen in beam-foil excitation. The experimental results are presented, previous beam-foil measurements are reviewed, and the contributions and relations to fusion research are discussed.
Reaction of trialkylboranes with sodium diethyldihydroaluminate in the presence of 1,4-diazabicyclo[2.2.2]octane. a convenient, general method for preparation of sodium trialkylborohydrides

Abstract Trialkylboranes in tetrahydrofuran (THF) or diethyl ether (EE) solutions, including those with exceptionally large steric requirements, react readily with toluene solutions of sodium diethyldihydroaluminate in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) to yield the corresponding sodium trialkylborohydrides and diethylaluminum hydride. The diethylaluminum hydride precipitates from solution as its DABCO adduct, with the use of EE as solvent facilitating the separation. This reaction constitutes a convenient, general method for preparing sodium trialkylborohydrides.
The Initial-Boundary Value Problem for the Korteweg–de Vries Equation

We prove local well-posedness of the initial-boundary value problem for the Korteweg–de Vries equation on right half-line, left half-line, and line segment, in the low regularity setting. This is accomplished by introducing an analytic family of boundary forcing operators.
Gustiness: The driver of glacial dustiness?

During glacial periods of the Late Quaternary, mineral dust emissions from Earth’s dominant source areas were a factor of 2e4 higher than interglacial levels. The causes of these fluctuations are poorly understood, limiting interpretation of dust flux records and assessment of dust’s role in past climate changes. Here we consider several possible drivers of glacialeinterglacial dust flux changes in an effort to assess their relative importance. We demonstrate that a wide range of data supports wind gustiness as a primary driver of global dust levels, with steepened meridional temperature gradients during glacial periods causing increases in dust emissions through increases in the intensity and frequency of highspeed wind events in dust source areas. We also find that lake level records near dust source areas do not consistently support the hypothesis that aridity controls glacialeinterglacial dust emission changes on a global scale, and we identify evidence negating atmospheric pCO2 and sea level as dominant controls. Glaciogenic sediment supply, vegetation and aridity changes appear to be locally important factors but do not appear to explain the global nature of glacialeinterglacial dust flux changes. We suggest that the gustiness hypothesis is aviable explanation for the close correspondence between dust emissions and high-latitude temperatures observed in paleorecords and is worthy of further testing.
Local maps and the representation theory of operator algebras

Using representation theory techniques we prove that various spaces of derivations or one-sided multipliers over certain operator algebras are reflexive. A sample result: any bounded local derivation (local left multiplier) on an automorphic semicrossed product is a derivation (resp. left multiplier). In the process we obtain various results of independent interest. In particular, the finite dimensional nest representations of the tensor algebra of a topological graph separate points.
ATMOSPHERIC CIRCULATION OF HOT JUPITERS: A SHALLOW THREE-DIMENSIONAL MODEL

Remote observing of exoplanetary atmospheres is now possible, offering us access to circulation regimes unlike any of the familiar solar system cases. Atmospheric circulation models are being developed to study these new regimes but model validations and intercomparisons are needed to establish their consistency and accuracy. To this end, we present a simple Earth-like validation of the pseudospectral solver of meteorological equations called Intermediate General Circulation Model (IGCM), based on Newtonian relaxation to a prescribed latitudinal profile of equilibrium temperatures. We then describe a straightforward and idealized model extension to the atmospheric flow on a hot Jupiter with the same IGCM solver. This shallow, three-dimensional hot Jupiter model is based on Newtonian relaxation to a permanent day-night pattern of equilibrium temperatures and the absence of surface drag. The baroclinic regime1 of the Earth's lower atmosphere is contrasted with the more barotropic regime of the simulated hot Jupiter flow. For plausible conditions at the 0.1-1 bar pressure level on HD 209458b, the simulated flow is characterized by unsteadiness, subsonic wind speeds, a zonally perturbed superrotating equatorial jet and large-scale polar vortices. Violation of the Rayleigh-Kuo inflexion point criterion on the flanks of the accelerating equatorial jet indicates that barotropic (horizontal shear) instabilities may be important dynamical features of the simulated flow. Similarities and differences with previously published simulated hot Jupiter flows are briefly noted.
Necrotizing Fasciitis After Plastibell Circumcision

Necrotizing fasciitis is a potentially life-threatening infection of subcutaneous tissues and Scarpa's fascia that rarely affect neonates. We report the occurrence of this devastating infection in two neonates after routine Plastibell circumcision. These case reports highlight the presentation and management of this complication after a relatively routine and frequently performed operation. This report also emphasizes the differences between cellulitis and necrotizing fasciitis and suggests strategies for management. (J Pediatr 1997;131:459-462) Necrotizing fasciitis is a surgical emergency resulting from infection of the subcutaneous tissue and superficial fascia by a variety of bacteria. In the neonatal age group it may have a mortality rate greater than 70% 1 Successful treatment requires accurate diagnosis with early and aggressive debridement of the involved tissue, broad-spectrum intravenous antibiotic coverage, and intensive support care. We report two cases in newborn male infants in whom necrotizing fasciitis developed after Plastibell (Hollister, Libertyville, Ill.) circumcision. These cases illustrate the devastating nature of this type of infection and show how aggressive treatment can lead to a satisfactory outcome. CASE REPORTS
Spitzer spectral line mapping of supernova remnants. I. Basic data and principal component analysis

We report the results of spectroscopic mapping observations carried out toward small (1' × 1') regions within the supernova remnants W44, W28, IC 443, and 3C 391 using the Infrared Spectrograph (IRS) of the Spitzer Space Telescope. These observations, covering the 5.2-37 μm spectral region, have led to the detection of a total of 15 fine-structure transitions of Ne+, Ne++, Si+, P+, S, S++, Cl+, Fe+, and Fe++; the S(0)-S(7) pure rotational lines of molecular hydrogen; and the R(3) and R(4) transitions of hydrogen deuteride. In addition to these 25 spectral lines, the 6.2, 7.7, 8.6, 11.3, and 12.6 μm PAH emission bands were also observed. Most of the detected line transitions have proven strong enough to map in several sources, providing a comprehensive picture of the relative distribution of the various line emissions observable in the Spitzer IRS bandpass. A principal component analysis of the spectral-line maps reveals that the observed emission lines fall into five distinct groups, each of which may exhibit a distinct spatial distribution: (1) lines of S and H2(J > 2); (2) the H2 S(0) line; (3) lines of ions with appearance potentials less than 13.6 eV; (4) lines of ions with appearance potentials greater than 13.6 eV, not including S++; (5) lines of S++. Lines of group 1 likely originate in molecular material subject to a slow, nondissociative shock that is driven by the overpressure within the supernova remnant, and lines in groups 3-5 are associated primarily with dissociative shock fronts with a range of (larger) shock velocities. The H2 S(0) line shows a low-density diffuse emission component and, in some sources, a shock-excited component.
Perturbative matching of the NRQCD heavy-light axial current

Abstract A one-loop matching calculation between Lattice NRQCD adn full QCD for the heavy-light axial current is described and the effects of renormalization on f B are discussed.
SHOCKED AND SCORCHED: THE TAIL OF A TADPOLE IN AN INTERSTELLAR POND

We report multi-wavelength observations of the far-infrared source IRAS 20324+4057, including high-resolution optical imaging with the Hubble Space Telescope, and ground-based near-infrared, millimeter-wave and radio observations. These data show an extended, limb-brightened, tadpole-shaped nebula with a bright, compact, cometary nebula located inside the tadpole head. Our molecular line observations indicate that the Tadpole is predominantly molecular with a total gas mass exceeding 3.7 M{sub Sun }. Our radio continuum imaging and archival Spitzer IRAC images show the presence of additional tadpole-shaped objects in the vicinity of IRAS 20324+4057 that share a common east-west head-tail orientation: we propose that these structures are small, dense molecular cores that originated in the Cygnus cloud and are now being (1) photoevaporated by the ultraviolet radiation field of the Cyg OB2 No. 8 cluster located to the northwest; and (2) shaped by ram pressure of a distant wind source or sources located to the west, blowing ablated and photoevaporated material from their heads eastward. The ripples in the tail of the Tadpole are interpreted in terms of instabilities at the interface between the ambient wind and the dense medium of the former.
Synthesis of (±)-tetramethoxy-sinensigenin A via an intramolecular Marson-type cyclization

The concise synthesis of (±)-tetramethoxy-sinensigenin A (2) is reported. The key C–C bond formation, which forged the [3.2.1]-bicyclic ether moiety, was the result of a regio- and diastereoselective intramolecular Marson-type cyclization via a pendent oxocarbenium cation intermediate.
The effect of silica-containing binders on the titanium/face coat reaction

The interactions of CP-Ti and Ti-6Al-4V with investment molds containing alumina/silica and yttria/silica face coat systems were studied. “Containerless” melting in argon was employed and small test samples were made by drop casting into the molds. The effects of the face coat material and mold preheat temperatures on the thickness of the alpha case in the drop castings were evaluated with microhardness and microprobe measurements. It was found that the thickness of the alpha case was the same, whether a yttria/silica or alumina/silica face coat was used, indicating that the silica binder can reduce the apparent inertness of a more stable refractory, such as yttria. It was also found that the alloyed titanium castings had a thinner alpha case than those produced from CP-Ti, which suggests that the thickness of the alpha case depends on the crystal structure of the alloy during cooling from high temperatures. Furthermore, the small drop castings made in small yttria crucibles used as molds exhibited little or no alpha case.
Pressure study of superconductivity and magnetism in pure and Rh-doped RuSr2GdCu2O8 materials

Abstract A hydrostatic pressure study was made on pure and Rh-doped specimens of the superconducting ferromagnetic compounds Ru 1− x Rh x Sr 2 GdCu 2 O 8 ( x = 0–0.15) by means of measurement of electrical resistivity vs temperature, in pressures up to 2 GPa. Partial substitution of Rh for Ru decreases the magnetization of the material, lowers both the magnetic ordering temperature T m , and the superconducting transition temperature T c , and promotes granularity. The effect of pressure for all compositions is an increase in both the intra- and inter-granular superconductivity transition temperatures, T c and T p respectively, as well as T m . The rate of change of each transition temperature with pressure first drops for Rh concentrations near 5%, increasing the latter for higher concentrations. While the rate of increase of T c with pressure for all compositions is 2–3 times lower than in YBCO materials, the simultaneous increase of T c and T m with pressure could support the notion of competition between superconductivity and ferromagnetism in these materials. The effect of pressure on the weak-links was a significant improvement of inter-granular connectivity.
Higher order PDE’s and iterated processes

We introduce a class of stochastic processes based on symmetric α-stable processes, for a ∈ (0,2j. These are obtained by taking Markov processes and replacing the time parameter with the modulus of a symmetric α-stable process. We call them α-time processes. They generalize Brownian time processes studied in Allouba and Zheng (2001), Allouba (2002), (2003), and they introduce new interesting examples. We establish the connection of α-time processes to some higher order PDE's for a rational. We also obtain the PDE connection of subordinate killed Brownian motion in bounded domains of regular boundary.
Using artificial neural networks to statistically fuse current iris segmentation techniques to improve limbic boundary localization

One of the basic challenges to robust iris recognition is iris segmentation. This paper proposes the use of an artificial neural network and a feature saliency algorithm to better localize boundary pixels of the iris. No circular boundary assumption is made. A neural network is used to near-optimally combine current iris segmentation methods to more accurate localize the iris boundary. A feature saliency technique is performed to determine which features contain the greatest discriminatory information. Both visual inspection and automated testing showed greater than 98 percent accuracy in determining which pixels in an image of the eye were iris pixels when compared to human determined boundaries.
Evolution of self-similar parabolic pulses in optical fiber amplifiers

We simulated the evolution of self-similar parabolic pulses (similaritons) in a normally dispersive fiber amplifier. The rate of development of a Gaussian pulse into the asymptotic parabolic regime has been studied. The model has been applied to an optical transmission system with a fiber amplifier. By calculating the Q-factor, we numerically determined the signal to noise performance of the pulse train along fiber length. For the parameters we used, a 6m long fiber amplifier with 20 dB gain is capable of amplifying 200Gb/s initial chirp-free Gaussian pulses of duration 0.4ps with no distortion and additional noise. The trade-off between pulse width and amplifier length has been studied.
Perturbed particle disks

The Boltzmann moment equations are solved to determine the velocity ellipsoid in a particle disk near an isolated satellite resonance. In a coordinate frame which rotates with the pattern speed of the perturbation potential, the solutions are stationary functions of the azimuthal angle. From the velocity ellipsoid we obtain the stress tensor due to particle collisions and consequently, the viscous angular momentum flux. We show that the magnitude of the rate of deformation tensor in a perturbed particle disk is bounded from above by KΩ(1 + τ^2)^½ where Ω is the orbital angular velocity, τ is the optical depth, and K is a dimensionless constant of order unity. It is also found that in sufficiently perturbed regions there are ranges of azimuthal angle within which the radial component of the angular momentum flux is negative. It is even possible for the angular momentum luminosity, the radial flux integrated over azimuth, to be negative. These results are important for understanding sharp edges and the decay of density waves in planetary rings. They are also relevant to the damping of differential precession and eccentricity in narrow ringlets.
A Rational Interpolation Scheme with Superpolynomial Rate of Convergence

The purpose of this study is to construct a high-order interpolation scheme for arbitrary scattered datasets. The resulting function approximation is an interpolation function when the dataset is exact, or a regression if measurement errors are present. We represent each datapoint with a Taylor series, and the approximation error as a combination of the derivatives of the target function. A weighted sum of the square of the coefficient of each derivative term in the approximation error is minimized to obtain the interpolation approximation. The resulting approximation function is a high-order rational function with no poles. When measurement errors are absent, the interpolation approximation converges to the target function faster than any polynomial rate of convergence.
Gold-catalyzed efficient synthesis of azepan-4-ones via a two-step [5+2] annulation

A surprisingly efficient synthesis of azepan-4-ones via a two-step [5+2] annulation is developed. This reaction involves a key gold catalysis and shows generally high regioselectivities and good to excellent diastereoselectivities.
A microprocessor selective encryption terminal for privacy protection

This paper reports on an experiment performed by the METREK Division of The MITRE Corporation from November 1975 through August 1976. The purpose of the experiment was to determine how effectively a low cost microcomputer could provide privacy protection to a user of a time-shared computer system. The microprocessor was used to selectively encrypt information entered at the terminal before transmission to the host computer so that the protected information never appears in plaintext form at the host computer. The advantages and disadvantages of this approach along with the operational details of the experimental system are presented.
Malnutrition and brain development

A P P R O X I M A T E L Y one haIf the population of the world has survived a period of serious nutritional deprivation during childhood? At the present moment more than 300 million children throughout the world are suffering from varying degrees of malnutrition. Although the severity of this undernutrition has not changed much, the age at which it strikes is changing. As countries begin to industrialize, breast-feeding becomes less and less frequent and malnutrition occurs at an earlier age. For example, in Chile, one of the more rapidly industrializing countries, breast-feeding is rarely practiced and the infant mortality rate during the early months of life remains among the highest in South America. Although many of these children will die, the vast majority will survive and join that half of the world's population which has been inadequately nourished during early childhood. What is the functional result of having survived malnutrition as an infant? Are these children doomed to
Two operations In character recognition: A partial replication

Subjects carried out a choice reaction time experiment in which they were required to press one lever ifa tachistoscopically flashed numeral was a member of a previously memorized list of numerals and a second lever if it was not a member of the list. The number of numerals in the list was varied from one to four. On half of the trials the numeral was partially masked by a pattern of visual noise. For one group a single fixed pattern of noise was used; for a second group four patterns presented in random order were used. Reaction time from the onset of the numeral to the lever press was found to be a linear function of list size, confirming Sternberg’s hypothesis that the list is scanned serially to determine a match. Partial masking was found to add a constant increment to reaction time for both groups, independent of set size. The increment was equal for both groups. The constancy of the reaction time increase contradicts Sternberg’s results in which the increment was found to be, in part, a function of list size. The results of the present study indicate that one cannot dismiss the possibility that Ss identify the character to the point of labeling prior to an attempt to determine list membership.
A geometric explanation of the transfer paradox in a stable economy

Abstract It has recently been shown [Chichilnisky, Journal of Development Economics (1980)] that in a three-agent two-good economy, the transfer paradox may occur at a Walrasian stable equilibrium. Our paper gives a geometric demonstration of the result, making the role of the third agent clear. It also generalises the earlier result in certain respects, showing inter alia that what is important is that the number of goods should exceed the number of agents.
Catalytic Applications of Early/Late Heterobimetallic Complexes

Transition metal complexes that combine electronically different metals are most readily designed by combining an early transition metal and a late transition metal, typically via a bridging ligand framework. These so-called “early/late” heterobimetallic complexes have recently proven active in a number of catalytic transformations that are not accessible with analogous monometallic complexes. This review discusses recent contributions to catalytic and stoichiometric transformations of early/late heterobimetallic complexes.
Lunar surface: changes in 31 months and micrometeoroid flux.

Comparison of pictures of the lunar surface taken 31 months apart by Surveyor 3 and Apollo 12 show only one change in the areas disturbed by Surveyor: a 2-millimeter particle, in a footpad imprint, that may have fallen in from the rim or been kicked in by an approaching astronaut. Vertical walls 6 centimeters high did not collapse and dark ejecta remained dark. No meteorite craters as large as 1.5 millimeters in diameter were seen on a smooth soil surface 20 centimeters in diameter; this indicates a micrometeoroid flux lower than 4 x 10 -7 micrometeoroids per square meter-second at an energy equivalent to about 3 x 10 -8 gram at 20 kilometers per second. This flux is near the lower limit of previous determinations.
Creating advice-taking reinforcement learners

Learning from reinforcements is a promising approach for creating intelligent agents. However, reinforcement learning usually requires a large number of training episodes. We present and evaluate a design that addresses this shortcoming by allowing a connectionist Q-learner to accept advice given, at any time and in a natural manner, by an external observer. In our approach, the advice-giver watches the learner and occasionally makes suggestions, expressed as instructions in a simple imperative programming language. Based on techniques from knowledge-based neural networks, we insert these programs directly into the agent’s utility function. Subsequent reinforcement learning further integrates and refines the advice. We present empirical evidence that investigates several aspects of our approach and shows that, given good advice, a learner can achieve statistically significant gains in expected reward. A second experiment shows that advice improves the expected reward regardless of the stage of training at which it is given, while another study demonstrates that subsequent advice can result in further gains in reward. Finally, we present experimental results that indicate our method is more powerful than a naive technique for making use of advice.
Currents induced by charges moving in semiconductor

Abstract The method of computation of currents induced on electrodes by charges moving in vacuum was introduced in Refs. [1] , [2] . This method was extended [3] for the case of a semiconductor with assumption that only fixed charges are presented. In presented paper, Ramo's method is applied for charges moving in a media without limitation of the presence of fixed charges only.
Maximum principles in analytical economics

The very name of my subject, economics, suggests economizing or maxi mizing. But Political Economy has gone a long way beyond home econo mics. Indeed, it is only in the last third of the century, within my own life time as a scholar, that economic theory has had many pretensions to being itself useful to the practical businessman or bureaucrat. I seem to recall that a great economist of the last generation, A. C. Pigou of Cam bridge University, once asked the rhetorical question, 'Who would ever think of employing an economist to run a brewery?' Well, today, under the guise of operational research and managerial economics, the fanciest of our economic tools are being utilized in enterprises both public and private. So at the very foundations of our subject maximization is involved. My old teacher, Joseph Schumpeter, went much farther. Instead of being content to say economics must borrow from logic and rational empirical enquiry, Schumpeter made the remarkable claim that man's ability to operate as a logical animal capable of systematic empirical induction was itself the direct outcome of the Darwinian struggle for survival. Just as man's thumb evolved in the struggle to make a living to meet his econo mic problem so did man's brain evolve in response to the economic problem. Coming forty years before the latest findings in ethology by Konrad Lorenz and Nikolaas Tinbergen, this is a rather remarkable insight. It would take me away from my present subject to more than mention the further view enunciated by Schumpeter [43] in launching the new subject of econometrics. Quantity, he said, is studied by the physicist or other natural scientist at a fairly late and sophisticated stage of the subject. Since a quantitative approach is, so to speak, at the discretion of the investigator, all the more credit to the followers of Galileo and Newton for taking the mathematical approach. But in economics, said Schumpeter, the very subject matter presents itself in quantitative form : take away the numerical magnitude of price or barter exchange-ratio and you have nothing left. Accounting does not benefit from arithmetic;
A comparison of screening mammography results from programs for women of different socioeconomic status

BACKGROUND The ability of screening mammography programs serving women of different socioeconomic status (SES) to diagnose early stage breast carcinoma in a comparably effective fashion has been questioned. METHODS Results of screening 50,653 women of lower SES were compared with those of screening 45,923 more socioeconomically advantaged women during the same period in New York State. Results were compared with those reported for the general population to the New York State cancer registry. RESULTS Additional workup was required for approximately 12% of the women in each group. Although more women of lower SES underwent biopsy, the positive predictive value of a biopsy recommendation was almost the same for the two populations (27% for women of higher SES vs. 25% for women of lower SES). Among women with breast carcinoma, ductal carcinoma in situ was diagnosed in 27% of more affluent women and 15% of women of lower SES, a considerable improvement from the 10% rate of diagnosis in the general population in New York State. Minimal cancers accounted for 54% of those diagnosed in more affluent women and at least 31% of those diagnosed in women of lower SES. CONCLUSIONS Screening mammography programs can be effective for women of lower SES and can be conducted as efficiently as they are for more affluent women. Differences in diagnosis of small cancers in the two groups reported in this article may reflect differences in age and patterns of prior screening experience in the two populations. Cancer 1998;82:1692-7. © 1998 American Cancer Society.
Formation, growth and survival; Small firm dynamics in the U.S. Economy

“Four out of five new firms fail within the first five years.” This statement has been made so many times that most people believe it is true. But it isn't. In fact, using a relatively new data source developed by the U.S. Small Business Administration, we found that on the average, 39.8 percent of new firms survive six or more years. This is equivalent to a failure rate of three out of five, substantially lower than popularly believed. Survival rates vary by industry with manufacturing having the greatest (46.9 percent) and construction the smallest (35.3 percent). More important, however, is the discovery that survival rates more than double for firms that grow. Even a small amount of growth boosts the average survival rate to 66.3 percent; that is two out of three growing firms survive. The earlier in the life of the business that growth occurs, the higher the chance of survival. But, most firms do not grow in the first four years. On average, only ten percent of firms show growth in the first four years. By the sixth year, however, 34.3 percent of the firms show growth and over fifty percent show growth within eight years. To put the old adage to rest, two out of five new firms survive at least six years and over half of the survivors grow.
Magnetic energy storage

Magnetic energy storage has become the foundation for near time and longer range electric utility applications and for current induction in the plasma of fusion devices. The fusion program embraces low loss superconductor strand development with integration into cables capable of carrying 50 kA in pulsed mode at high fields. This evolvement has been paralleled with pulsed energy storage coil development and testing from tens of kJ at low fields to a 20 MJ prototype tokamak induction coil at 7.5 T. Energy transfer times have ranged from 0.7 ms to several seconds. Electric utility magnetic storage for prospective application is for diurnal load leveling with massive systems to store 10 GWh at 1.8 K in a dewar structure suported on bedrock underground. An immediate utility application is a 30 MJ system to be used to damp power oscillations on the Bonneville Power Administration electric transmission lines. An off-shoot of this last work is a new program for electric utility VAR control with the potential for use to suppress subsynchronous resonance. Pulsed magnetic energy storage is not a widely developed technology. Current work is done almost exclusively in Japan and the United States. This paper does not cover past work or completed studies but presents work in progress, work planned, and recently completed unusual work.
A mild and efficient AgSbF6-catalyzed synthesis of fully substituted pyrroles through a sequential propargylation/amination/cycloisomerization reaction.

Abstract Development of an efficient synthesis of fully substituted pyrroles via a sequential propargylation/amination/cycloisomerization was accomplished using AgSbF6 as a catalyst. The one-pot three-component reaction of propargylic alcohols, 1,3-dicarbonyl compounds, and primary amines proceeds at a mild temperature, which prevents the formation of furan by-product. The reaction was also successfully applied to the more basic aliphatic amines with the addition of 1.1 equiv of acetic acid.
Mesh quality control for multiply-refined tetrahedral grids

A new algorithm for controlling the quality of multiply-refined tetrahedral meshes is presented in this paper. The basic dynamic mesh adaption procedure allows localized grid refinement and coarsening to efficiently capture aerodynamic flow features in computational fluid dynamics problems; however, repeated application of the procedure may significantly deteriorate the quality of the mesh. Results presented show the effectiveness of this mesh quality algorithm and its potential in the area of helicopter aerodynamics and acoustics.
Ten-year hip fracture incidence rate trends in a large California population, 1997-2006.

Hip fractures are a large public health problem with significant negative impact on an individual’s overall health and survival. But while the total numbers of persons affected by hip fractures may be anticipated to increase, incidence rates appear to be declining. To describe annual hip fracture incidence rate trends in an integrated health-care organization over 1997–2006, during which a proactive bone health program was initiated program-wide and other secular trends occurred in the population. For this ecologic trend study, we identified all men and women ≥45 years old as of January 1 of each year. Incident fractures for each year were identified using ICD-9 diagnosis codes 820–820.9, excluding all subjects who had fractures in prior years. Annual person-time at risk for hip fracture was determined from enrollment data. Sex- and age-specific and adjusted annual incidence rates were calculated. The overall annual hip fracture incidence rate for men declined from 1.52/1,000 person-years in 1997 to 1.29/1,000 person-years in 2006, a 15.3% (95% confidence interval [CI]=6.2–24.5) decrease. For women, incidence declined from 2.65/1,000 person-years in 1997 to 2.24/1,000 person-years in 2006, a 15.3% (95% CI=8.7–21.9) decrease. Among subjects aged 85 years or older, incidence rates for men declined from 27.0/1,000 to 18.9/1,000 person-years, and for women they declined from 32.7/1,000 to 27.1/1,000 person-years. Hip fracture incidence has been declining in all age groups over the past 10 years. While many factors may contribute to this decline, the results are consistent with a potential benefit of the active bone health intervention.