cssi/SciSciGPT-SciSciNet huggingface dataset:
DERIVING ULTRAMETRIC TREE STRUCTURES FROM PROXIMITY DATA CONFOUNDED BY DIFFERENTIAL STIMULUS FAMILIARITY

This paper presents a new procedure called TREEFAM for estimating ultrametric tree structures from proximity data confounded by differential stimulus familiarity. The objective of the proposed TREEFAM procedure is to quantitatively “filter out” the effects of stimulus unfamiliarity in the estimation of an ultrametric tree. A conditional, alternating maximum likelihood procedure is formulated to simultaneously estimate an ultrametric tree, under the unobserved condition of complete stimulus familiarity, and subject-specific parameters capturing the adjustments due to differential unfamiliarity. We demonstrate the performance of the TREEFAM procedure under a variety of alternative conditions via a modest Monte Carlo experimental study. An empirical application provides evidence that the TREEFAM outperforms traditional models that ignore the effects of unfamiliarity in terms of superior tree recovery and overall goodness-of-fit.
Modeling, actuation, and control of an active fluid vibration isolator

An integrated mathematical model for the dynamics, actuation, and control of an active fluid/elastomeric tuned vibration isolator in a two mass system is presented. The derivation is based on the application of physical principles for mechanics, fluid continuity, and electromagnetic circuits. Improvement of the passive isolator performance is obtained with a feedback scheme consisting of frequency shaped notch compensator in series with integral control ofoutput acceleration and combined with proportional control of the fluid pressure in the isolator. The control is applied via an electromagnetic actuator for excitation of the fluid in the track connecting the two pressure chambers of the isolator. Closed loop system equations are transformed to a nondimensional state space representation and a key dimensionless parameter for isolator-actuator interaction is defined. A numerical example is presented to show the effect of actuator parameter selection on system damping, the performance improvement of the active over the passive isolator, the robustness of the control scheme to parameter variation, and the electrical power requirements for the actuator.
Cellular and molecular mechanisms responsible for progression of Barrett's metaplasia to esophageal carcinoma

Barrett's metaplasia is found in approximately 12% to 18% of patients undergoing upper endoscopy for symptoms of reflux. Barrett's metaplasia is a premalignant condition and remains the number one risk factor for developing esophageal adenocarcinoma. There has been an increase in the incidence of esophageal adenocarcinoma in the past two decades, making it the most rapidly rising cancer in the United States and Western Europe. This article describes the progression from Barrett's metaplasia to esophageal adenocarcinoma and predictors for the development of adenocarcinoma in Barrett's metaplasia. Barrett's metaplasia represents a histological mosaic, with dysplastic tissue adjacent to non-dysplastic tissue. The histologic changes leading to adenocarcinoma are accompanied by alterations at the molecular level, including the accumulation of gene mutations and changes in gene expression. The determination of the molecular events that occur in the transition from normal esophageal squamous mucosa to dysplasia and to esophageal adenocarcinoma have lead to a better understanding of the process of the transformation to adenocarcinoma. This knowledge will lead to better biomarkers to diagnose and assess cancer risk.
Adiabatic Invariant of the Harmonic Oscillator

The problem of a vibrating harmonic oscillator whose frequency is changing in time is considered in the case where the frequency $\ensuremath{\omega}$ is initially constant, varies in an arbitrary fashion and becomes constant again. It is found that the relative change of the quantity, the energy divided by the frequency, in the final region from its value in the initial region is zero to as many orders in the rate of change of $\ensuremath{\omega}$ as $\ensuremath{\omega}$ has continuous derivatives. For the case where there is a break in the $N\mathrm{th}$ derivative of $\ensuremath{\omega}$ the relative change is given to this order.
A multi-species reactive transport model to estimate biogeochemical rates based on single-well push-pull test data

Push-pull tests are a popular technique to investigate various aquifer properties and microbial reaction kinetics in situ. Most previous studies have interpreted push-pull test data using approximate analytical solutions to estimate (generally first-order) reaction rate coefficients. Though useful, these analytical solutions may not be able to describe important complexities in rate data. This paper reports the development of a multi-species, radial coordinate numerical model (PPTEST) that includes the effects of sorption, reaction lag time and arbitrary reaction order kinetics to estimate rates in the presence of mixing interfaces such as those created between injected ''push'' water and native aquifer water. The model has the ability to describe an arbitrary number of species and user-defined reaction rate expressions including Monod/Michelis-Menten kinetics. The FORTRAN code uses a finite-difference numerical model based on the advection-dispersion-reaction equation and was developed to describe the radial flow and transport during a push-pull test. The accuracy of the numerical solutions was assessed by comparing numerical results with analytical solutions and field data available in the literature. The model described the observed breakthrough data for tracers (chloride and iodide-131) and reactive components (sulfate and strontium-85) well and was found to be useful for testing hypotheses related to the complex set of processes operating near mixing interfaces.
Catalysis and chemodivergence in the interrupted, formal homo-Nazarov cyclization using allylsilanes.

A chemodivergent, Lewis acid catalyzed allylsilane interrupted formal homo-Nazarov cyclization is disclosed. With catalytic amounts of SnCl4 and in the presence of allyltrimethylsilane, a formal Hosomi–Sakurai-type allylation of the oxyallyl cation intermediate is observed. A variety of functionalized donor–acceptor cyclopropanes and allylsilanes were shown to be amenable to the reaction transformation and the allyl products were formed in up to 92% yield. Under dilute reaction conditions with stoichiometric SnCl4 and at reduced temperatures, an unusual formal [3 + 2]-cycloaddition between the allylsilane and the oxyallyl cation occurred to give hexahydrobenzofuran products in up to 69% yield.
An unexpected product arising from metal alkylidene mediated ring-closing diene metathesis

Abstract Ring-closing diene metathesis of siloxytriene 3 surprisingly afforded siloxytricycle 9 in which the newly formed ring is one carbon unit smaller than expected.
The Ringed Spiral Galaxy NGC 4622. I. Photometry, Kinematics, and the Case for Two Strong Leading Outer Spiral Arms

The intriguing nearly face-on southern ringed spiral galaxy NGC 4622, the first galaxy definitively shown to have leading spiral structure, is revisited in this paper with new images from the Hubble Space Telescope's (HST) WFPC2, together with ground-based optical and near-IR imaging, and a Fabry-Perot Hα velocity field. The data provide new information on the disk/bulge/halo mix, rotation curve, star formation in the galaxy, and the sense of winding of its prominent spiral arms. Previously, we suggested that the weaker, inner single arm most likely has the leading sense, based on a numerical simulation. Now, taking advantage of HST resolution and using de Vaucouleurs' standard extinction and reddening technique to determine the near side of the galaxy's slightly tilted disk, we come to the more surprising conclusion that the two strong outer arms have the leading sense. We suggest that this highly unusual configuration may be the result of a past minor merger or mild tidal encounter. Possible evidence for a minor merger is found in a short, central dust lane, although this is purely circumstantial and an unrelated interaction with a different companion could also be relevant. The leading arms may be allowed to persist because NGC 4622 is dark halo dominated (i.e., not "maximum disk" in the inner regions) and displays a significantly rising rotation curve. The new HST observations also reveal a rich globular cluster system in the galaxy. The mean color of these clusters is (V-I)0 = 1.04, and the specific frequency is 3.4 ± 0.6. The luminosity function of these clusters confirms the membership of NGC 4622 in the Centaurus Cluster.
An efficient, thermally stable cerium-based silicate phosphor for solid state white lighting.

A novel cerium-substituted, barium yttrium silicate has been identified as an efficient blue-green phosphor for application in solid state lighting. Ba9Y2Si6O24:Ce3+ was prepared and structurally characterized using synchrotron X-ray powder diffraction. The photoluminescent characterization identified a major peak at 394 nm in the excitation spectrum, making this material viable for near-UV LED excitation. An efficient emission, with a quantum yield of ≈60%, covers a broad portion (430–675 nm) of the visible spectrum, leading to the blue-green color. Concentration quenching occurs when the Ce3+ content exceeds ≈3 mol %, whereas high temperature photoluminescent measurements show a 25% drop from the room temperature efficiency at 500 K. The emission of this compound can be red-shifted via the solid solution Ba9(Y1–yScy)1.94Ce0.06Si6O24 (y = 0.1, 0.2), allowing for tunable color properties when device integration is considered.
Nonlinear Modeling of Mechanical Gas Face Seal Systems Using Proper Orthogonal Decomposition

An approach based on proper orthogonal decomposition and Galerkin projection is presented for developing low-order nonlinear models of the gas film pressure within mechanical gas face seals. A technique is developed for determining an optimal set of global basis functions for the pressure field using data measured experimentally or obtained numerically from simulations of the seal motion. The reduced-order gas film models are shown to be computationally efficient compared to full-order models developed using the conventional semidiscretization methods. An example of a coned mechanical gas face seal in a flexibly mounted stator configuration is presented. Axial and tilt modes of stator motion are modeled, and simulation studies are conducted using different initial conditions and force inputs. The reduced-order models are shown to be applicable to seals operating within a wide range of compressibility numbers, and results are provided that demonstrate the global reduced-order model is capable of predicting the nonlinear gas film forces even with large deviations from the equilibrium clearance.
On the high T phase transition in the gauged SU(2) Higgs model

Abstract We study the effective field thoery of a weakly coupled (3+1)D gauged o 4 type model at high temperature. Our model has 4 N real scalars ( N complex Higgs doublets) and a gauge group SU(2) which is spontaneously broken by a nonzero scalar field VEV at zero temperature. We find, for sufficiently large N , that the transition from the high temperature symmetry restoring phase to the low temperature phase can be either first order or second order depending on the ratio of the gauge coupling to the scalar self-coupling.
Cell mediated immunity in virus infections

The discovery of the molecular nature of T cell-mediated immunity is reviewed in a historical context. Current approaches to understanding virus-induced inflammatory processes are described.
Rotary Transformer Design with Fixed Magnetizing and/or Leakage Inductances

A design algorithm is considered for transformers that must transfer electric power across a rotating interface. Among other features, this procedure allows the designer to minimize either weight or losses for either a fixed magnetizing inductance or a fixed leakage inductance. Numerical results are included to indicate the design tradeoffs between various parameters.
F-pure thresholds of binomial hypersurfaces

In this note, we use estimates given in the recent preprint [Her11b]to deduce a formula for the F-pure threshold of a binomial hypersurface over a field of prime characteristic. These formulas are given in terms of the associated splitting polytope, and remain valid over any characteristic.
Ultraviolet measurements in planetary atmospheres.

The impact of the latest optical and electronic component developments on far uv rocket spectrophotometry is discussed. Results of some recent experiments studying earth airglow and aurorae are reviewed. It is shown that weaker spectral features can be measured in the region 1100 A to 3000 A than at any longer wavelength.
Inter-State Dynamics of Invention Activities, 1930-2000 ¤

We study the dynamics of the cross-section distribution of patents per capita for the 48 continental US states from 1930 to 2000 using a discrete-state Markov chain. We test for and find evidence in favor of the (knowledge) convergence hypothesis. The distribution of patents is converging to a limiting distribution that is significantly more concentrated than its initial distribution. States in the extreme are more mobile than states in the middle of the cross-sectional distribution and are likely to move to the middle. However, the rate of convergence to the limiting distribution is ‘slow’. Copyright © 2006 John Wiley & Sons, Ltd.
Study of local reconnection physics in a laboratory plasma

A short review of physics results obtained in the Magnetic Reconnection Experiment (MRX) is given with an emphasis on the local features of magnetic reconnection in a controlled environment. Stable two-dimensional (2D) current sheets are formed and sustained by induction using two internal coils. The observed reconnection rates are found to be quantitatively consistent with a generalized Sweet-Parker model which incorporates compressibility, unbalanced upstream-downstream pressure, and the effective resistivity. The latter is significantly enhanced over its classical values in the low collisionality regime. Strong local ion heating is measured by an optical probe during the reconnection process, and at least half of the increased ion energy must be due to nonclassical processes, consistent with the resistivity enhancement. Characteristics of high frequency electrostatic and electromagnetic fluctuations detected in the current sheet suggest presence of the lower-hybrid-drift like waves with significant magnetic components. The detailed structures of current sheet are measured and compared with Harris theory and two-fluid theory.
A prospective longitudinal evaluation of pregnancy in the Marfan syndrome.

OBJECTIVE: We undertook a prospective evaluation of the outcomes of pregnancy, both maternal and fetal, and the long-term impact of pregnancy on Marfan syndrome in a series of consecutive, unselected patients. STUDY DESIGN: Forty-five pregnancies in 21 Marfan syndrome patients were prospectively observed in one institution between 1983 and 1992. During pregnancy, patients were monitored with serial echocardiograms and close attention to symptoms. Maternal and fetal outcomes were recorded, and echocardiographic data were analyzed by least-squares regression. Eighteen of the patients were followed up for 15 months to 13 years after the completion of their last pregnancy for investigation of the long-term impact of pregnancy on the cardiovascular manifestations of Marfan syndrome. RESULTS: Aortic dissection occurred in two patients, both with increased risk for dissection established before pregnancy. The incidence of obstetric complications otherwise did not exceed that in the general population. Echocardiographic data demonstrated little to no change in aortic root diameter throughout pregnancy in most patients. Long-term follow-up showed no apparent worsening of cardiovascular status attributable to pregnancy in comparison with a group of 18 women with Marfan syndrome who were of similar age, had a similar degree of disease severity, and underwent no pregnancies. CONCLUSIONS: Patients with Marfan syndrome in whom cardiovascular involvement is minor and aortic root diameter is <40 mm usually tolerate pregnancy well, with favorable maternal and fetal outcomes, and without subsequent evidence of aggravated aortic root dilatation over time.
Electrophilic nitration of aromatics in ionic liquid solvents.

Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Hunig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.
Photoemission from Ordered Stripe Phases

A phase separation model for stripes has found good agreement with photoemission experiments and with other studies which suggest a termination of the striped phase in the slightly overdoped regime. Here the model is extended in a number of respects. In particular, a discussion of the nature of the charged stripes is presented, suggesting how density waves, superconductivity, and strong correlations can compete with the quantum size effects inherent in narrow stripes. The anomalous doping dependence of the chemical potential is explained.
Core Noise Diagnostics of Turbofan Engine Noise Using Correlation and Coherence Functions

Cross-correlation and coherence functions are used to look for periodic acoustic components in turbofan engine combustor time histories, to investigate direct and indirect combustion noise source separation based on signal propagation time delays, and to provide information on combustor acoustics. Using the cross-correlation function, time delays were identified in all cases, clearly indicating the combustor is the source of the noise. In addition, unfiltered and low-pass filtered at 400 Hz signals had a cross-correlation time delay near 90 ms, while the low-pass filtered at less than 400 Hz signals had a cross-correlation time delay longer than 90 ms. Low-pass filtering at frequencies less than 400 Hz partially removes the direct combustion noise signals. The remainder includes the indirect combustion noise signal, which travels more slowly because of the dependence on the entropy convection velocity in the combustor. Source separation of direct and indirect combustion noise is demonstrated by proper use of low-pass filters with the cross-correlation function for a range of operating conditions. The results may lead to a better idea about the acoustics in the combustor and may help develop and validate improved reduced-order physics-based methods for predicting direct and indirect combustion noise.
The Impact of Macroscopic Epistasis on Long-Term Evolutionary Dynamics

Genetic interactions can strongly influence the fitness effects of individual mutations, yet the impact of these epistatic interactions on evolutionary dynamics remains poorly understood. Here we investigate the evolutionary role of epistasis over 50,000 generations in a well-studied laboratory evolution experiment in Escherichia coli. The extensive duration of this experiment provides a unique window into the effects of epistasis during long-term adaptation to a constant environment. Guided by analytical results in the weak-mutation limit, we develop a computational framework to assess the compatibility of a given epistatic model with the observed patterns of fitness gain and mutation accumulation through time. We find that a decelerating fitness trajectory alone provides little power to distinguish between competing models, including those that lack any direct epistatic interactions between mutations. However, when combined with the mutation trajectory, these observables place strong constraints on the set of possible models of epistasis, ruling out many existing explanations of the data. Instead, we find that the data are consistent with a “two-epoch” model of adaptation, in which an initial burst of diminishing-returns epistasis is followed by a steady accumulation of mutations under a constant distribution of fitness effects. Our results highlight the need for additional DNA sequencing of these populations, as well as for more sophisticated models of epistasis that are compatible with all of the experimental data.
The Hall Effect and Specific Resistance of Cathodically Deposited Films of Gold

Hall coefficient for sputtered films of gold was determined for films varying in thickness from about 10 m\ensuremath{\mu} to 80 m\ensuremath{\mu}, and was found to be independent of the current (even though current densities up to ${10}^{6}$ amp./${\mathrm{cm}}^{2}$ were used), of the magnetic field (3 to 28 kilogauss), and of the thickness (computed from the surface density), and of previous treatment of the film, and to have the same value as for bulk metal, 643\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$. This is accurate to one per cent since the high current densities used gave e.m.fs. of over a milli-volt. The constancy of the coefficient agrees with the theory that the sputtered particles have individually the same properties as the bulk metal.Specific resistance of sputtered films of gold is erratic for films less than 10 m\ensuremath{\mu} thick, but for thicker films is proportional to $\frac{\ensuremath{\rho}}{(\ensuremath{\sigma}\ensuremath{-}{\ensuremath{\sigma}}_{0})}$ where $\ensuremath{\sigma}$ is surface density and $\ensuremath{\rho}$ is the density. The specific resistance $r$ came out about 3 times the value for bulk metal. The high value is doubtless due to poor electrical contact between particles. From the value of the constant ${\ensuremath{\sigma}}_{0}$, 20\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$ gm/${\mathrm{cm}}^{2}$, the average size of the particles is of the order of ${10}^{\ensuremath{-}6}$ cm.
Flux Trapped State Versus Glassy State in Superconducting BaErCuO and BaYCuTiO

The temperature dependent magnetization, M(T), of superconducting BaErCuO and BaYCuTiO was measured via the BTi SQUID susceptometer. In the zero field cooling case, M(T) of BaErCuO was found to be similar to that of Pb. But, M(T) of BaYCuTiO was found to decrease rapidly with T and be almost linear in T. However, in the field cooling case the fluxoids were found to be trapped at all T below Tc, and its amount was found to depend on Ts at which the sample starts to be cooled, as observed in Pb. The ergodic limiting points were not observed within the chosen parameters. The irreversibility of magnetization observed in both BaErCuO and BaYCuTiO is attributed to the fluxoids, trapped during the field cooling process.
Supersonic turbomachine rotor flutter control by aerodynamic detuning

A mathematical model is developed to analyze the flutter stability characteristics of an aerodynamically detuned rotor operating in a supersonic inlet flowfield with a supersonic axial component. Alternate-blade aerodynamic detuning is considered, accomplished by alternating the circumferential spacing of adjacent rotor blades. The unsteady aerodynamics are determined by developing an influence coefficient technique which is appropriate for both aerodynamically tuned and detuned rotor configurations. The effects of this detuning on the flutter stability characteristics of supersonic axial flow rotors are then demonstrated by applying this model to baseline 12-bladed rotors. Results show that, dependent on the specific blade row and flowfield geometry, alternate blade aerodynamic detuning is a viable flutter control mechanism for supersonic through-flow rotors.
WARM DUSTY DEBRIS DISKS AND DISTANT COMPANION STARS: V488 PER AND 2M1337

A possible connection between the presence of large quantities of warm (T ? 200?K) circumstellar dust at youthful stars and the existence of wide-separation companion stars has been noted in the literature. Here we point out the existence of a distant companion star to V488 Per, a K-type member of the ? Persei cluster with the largest known fractional excess infrared luminosity (~16%) of any main sequence star. We also report the presence of a distant companion to the previously recognized warm dust star 2M1337. With these discoveries the existence of a cause and effect relationship between a distant companion and large quantities of warm dust in orbit around youthful stars now seems compelling.
Direct numerical simulations of turbulent flows over superhydrophobic surfaces

Direct numerical simulations (DNSs) are used to investigate the drag-reducing performance of superhydrophobic surfaces (SHSs) in turbulent channel flow. SHSs combine surface roughness with hydrophobicity and can, in some cases, support a shear-free air–water interface. Slip velocities, wall shear stresses and Reynolds stresses are considered for a variety of SHS microfeature geometry configurations at a friction Reynolds number of Reτ ≈ 180. For the largest microfeature spacing studied, an average slip velocity over 75% of the bulk velocity is obtained, and the wall shear stress reduction is found to be nearly 40%. The simulation results suggest that the mean velocity profile near the superhydrophobic wall continues to scale with the wall shear stress but is offset by a slip velocity that increases with increasing microfeature spacing.
Test sets for integer programs

In this paper I discuss various properties of the simplicial complex of maximal lattice free bodies associated with a matrix A. If the matrix satisfies some mild conditions, and is generic, the edges of the complex form the minimal test set for the family of integer programs obtained by selecting a particular row of A as the objective function, and using the remaining rows to impose constraints on the integer variables. © 1997 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.
Reduction products of 3(2H)-cinnolinones

Reduction of 3(2H)-cinnolinone with zinc and ammonium hydroxide forms 1,4-dihydro-3(2H)-cinnolinone which rapidly rearranges to 1-amino-2-indolinone (1-aminooxindole) in acid solution. 1,4-Dihydro-2-methyl-3(2H)-cinnolinone is formed from 2-methyl-3(2H)-cinnolinone under the same conditions, but its rearrangement to 1-(N-methylamino)-2-indolinone (1-(N-methylamino)oxindole) in acid solution is much slower.
Numerical algorithms and results for SC-cut quartz plates vibrating at the third harmonic overtone of thickness shear

Finite element matrix equations, derived from two-dimensional piezoelectric high frequency plate theory are solved to study the vibrational behavior of the third overtone of thickness shear in square and circular SC-cut quartz resonators. The mass-loading and electric effects of electrodes are included. A perturbation method which reduces the memory requirements and computational time significantly is employed to calculate the piezoelectric resonant frequencies. A new storage scheme is introduced which reduces memory requirements for mass matrix by about 90% over that of the envelope storage scheme. Substructure techniques are used in eigenvalue calculation to save storage. Resonant frequency and the mode shapes of the harmonic third overtone thickness shear vibrations for square and circular plates are calculated. A predominant third overtone thickness shear displacement, coupled with the third overtone of thickness stretch and thickness twist, is observed. Weak coupling between the third order thickness shear displacement and the zeroth-, first-, and second-order displacements is noted. The magnitudes of the lower order displacements are found to be about two orders smaller than that of the third overtone thickness shear displacement. >
Magnitude and timing of temperature change in the Indo-Pacific warm pool during deglaciation

Ocean-atmosphere interactions in the tropical Pacific region have a strong influence on global heat and water vapour transport and thus constitute an important component of the climate system(1,2). Changes in sea surface temperatures and convection in the tropical Indo-Pacific region are thought to be responsible for the interannual to decadal climate variability observed in extratropical regions(1,3), but the role of the tropics in climate changes on millennial and orbital timescales is less clear. Here we analyse oxygen isotopes and Mg/Ca ratios of foraminiferal shells from the Makassar strait in the heart of the Indo-Pacific warm pool, to obtain synchronous estimates of sea surface temperatures and ice volume. We find that sea surface temperatures increased by 3.5-4.0 degreesC during the last two glacial-interglacial transitions, synchronous with the global increase in atmospheric CO2 and Antarctic warming, but the temperature increase occurred 2,000-3,000 years before the Northern Hemisphere ice sheets melted. Our observations suggest that the tropical Pacific region plays an important role in driving glacial-interglacial cycles, possibly through a system similar to how El Nino/Southern Oscillation regulates the poleward flux of heat and water vapour.
‘A minimum of urbanism and a maximum of ruralism’: the Cuban experience†

PIP: The case of Cuba provides social scientists with reasonably good information on urbanization policies and their implementation in 1 developing country committed to socialism. The demographic context is considered, and Cuban efforts to eliminate the rural-urban contradiction and to redefine the role of Havana are described. The impact of these policies is analyzed in terms of available data on urbanization patterns since January 1959 when the revolutionaries marched into Havana. Prerevolutionary urbanization trends are considered. Fertility in Cuba has declined simultaneously with mortality and even more rapidly. Projections assume a 1.85% annual growth rate, resulting in a population of nearly 15 million by the year 2000. Any estimate regarding the future trend in population growth must depend on prognosis of general living conditions and of specific government policies regarding contraception, abortion, female labor force participation, and child care facilities. If population growth in Cuba has been substantial, but less dramatic than that of many other developing countries, urban growth presents a similar picture. Cuba's highest rate of growth of the population living in urban centers with a population over 20,000, in any intercensal period during the 20th century, was 4.1%/year for 1943-1953. It dropped to 3.0% in the 1953-1970 period. Government policies achieved a measure of success in stemming the tide of rural-urban migration, but the aims of the revolutionary leadership went further. The objective was for urban dwellers to be involved in agriculture, and the living standards of the rural population were to be raised to approximate those of city dwellers. The goal of "urbanizing" the countryside found expression in a program designed to construct new small towns which could more easily be provided with services. A slowdown in the growth of Havana, and the concomitant weakening of its dominant position, was intended by the revolutionary leadership. Offical policies have been enunciated that connect the reduction in the dominance of Havana with the slowdown in urban growth and the urbanization of the countryside. Evidence is presented which suggests achievements along all of these dimensions, but by 1970 they were, as yet, quite limited.
Highly stereoselective C-C bond formation by rhodium-catalyzed tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor carbenoids and chiral allylic alcohols.

The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium carbenoids and chiral allyl alcohols is a convergent C–C bond forming process, which generates two vicinal stereogenic centers. Any of the four possible stereoisomers can be selectively synthesized by appropriate combination of the chiral catalyst Rh2(DOSP)4 and the chiral alcohol.
Correlated Equilibria in Some Classes of Two-Person Games

A correlated equilibrium in a two-person game is “good” if for everyNash equilibrium there is a player who prefers the correlated equilibrium to theNash equilibrium. If a game is “best-response equivalent” to a two-person zero-sum game, then it has no good correlated equilibria. But games which are “almost strictly competitive” or “order equivalent” to a two-person zero-sum game may have good correlated equilibria.
Laplacian-Based Models for the Exchange Energy

Recent Quantum Monte Carlo data for the exchange-correlation energy density of pseudopotential systems strongly suggest the value of using the Laplacian of the density as a variable for constructing first-order corrections to the local density approximation of density functional theory. We report on an exchange functional built on these observations and extended to the all-electron case. The model keeps the typical properties of constraint-based generalized gradient approximations (GGAs) and also has a finite-valued potential at the nucleus, unlike the GGA. Problems with oscillatory behavior in the potential due to higher order derivatives are controlled by a curvature minimization constraint. The results are tested against exact potentials for the He and Ne atom. A combination of gradient and Laplacian as suggested by a gradient expansion of the exchange hole gives the best overall results. © 2012 Wiley Periodicals, Inc.
THE CULTIVATION OF TISSUE IN PLASMA FROM ALIEN SPECIES

1. Rat sarcoma may be cultivated in mouse plasma and guinea pig plasma, and the growth differs only in extent from that observed in rat plasma. The cells may show active wandering in guinea pig plasma after thirty days, if transferred at proper intervals to fresh medium. 2. Rabbit plasma is less suitable than that of guinea pigs and mice for the growth of rat sarcoma; growth is slow, but it may continue for twelve days. 3. The duration of growth of rat sarcoma in dog plasma is from two to three days. 4. The duration of the growth of rat sarcoma in pigeon plasma is four to five days. Transferring the tissue to fresh pigeon plasma does not lengthen the period of activity. 5. No growth whatever is observed of mouse and rat tissues in goat plasma. Studies of the fate of the cells indicate the presence in goat serum of a substance toxic for these tissues. 6. In preparations of rat sarcoma in human plasma, liquefaction of fibrin is regularly observed. The phenomena of growth consist in an outwandering of cells along the cover glass, and, after four to six days, the formation of giant cells. Such giant cells are produced in larger number in the cultivation of rat spleen. 7. The degree of suitability of the different kinds of alien plasma used as culture media for mouse and rat tissues does not go hand in hand with the closeness of relationship of the species. 8. Rat spleen may be cultivated as readily in foreign plasma as the virulent transplantable tumors.
A symbolic manipulator for automated verification of reactive systems with heterogeneous data types

In this paper, we present the design and implementation of the Composite Symbolic Library, a symbolic manipulator for model checking systems with heterogeneous data types. Our tool provides a common interface for different symbolic representations, such as BDDs, for representing Boolean logic formulas and polyhedral representations for linear arithmetic formulas. Based on this common interface, these data structures are combined using a disjunctive composite representation. We propose several heuristics for efficient manipulation of this composite representation and present experimental results that demonstrate their performance. We used an object-oriented design to implement the Composite Symbolic Library. We imported the CUDD library (a BDD library) and the Omega Library (a linear arithmetic constraint manipulator that uses polyhedral representations) to our tool by writing wrappers around them which conform to our symbolic representation interface. Our tool supports polymorphic verification procedures which dynamically select symbolic representations based on the input specification. Our symbolic representation library can be used as an interface between different symbolic libraries, model checkers, and specification languages. We expect our tool to be useful in integrating different tools and techniques for symbolic model checking, and in comparing their performance.
Galileo completing VEEGA — A mid-term report

In December Galileo will complete its Venus-Earth-Earth-Gravity Assist (VEEGA) mission phase and will be placed on a direct trajectory to Jupiter arriving in December 1995. Galileo will be the first aircraft to orbit Jupiter and send a probe into its atmosphere and will perform an intensive and comprehensive investigation of the planet. Observations made during the October 1991 encounter with the asteroid Gaspra are discussed. The observation plan to be used for earth and moon observations during the December 1992 gravity assist encounter is described. The Galileo High-Gain Antenna (HGA) deployment anomaly status is reported and future corrective actions are outlined. The low-gain antenna contingency mission to be implemented if the HGA cannot be deployed is described and overall performance and status of the space craft are discussed. The selected tour for the Galileo Jupiter satellite-gravity-assist orbital tour is described and the decision rationale for performing the August 1993 asteroid Ida flyby option is presented.
Indexing moving points

We propose three indexing schemes for storing a set S of N points in the plane, each moving along a linear trajectory, so that any query of the following form can be answered quickly: Given a rectangle R and a real value t, report all K points of S that lie inside R at time t. We first present an indexing structure that, for any given constant e > 0, uses O(N/B) disk blocks and answers a query in O(N/B1/2+e + K/B)I/Os, where B is the block size. It can also report all the points of S that lie inside R during a given time interval. A point can be inserted or deleted, or the trajectory of a point can be changed, in O(log2BN) I/Os. Next, we present a general approach that improves the query time if the queries arrive in chronological order, by allowing the index to evolve over time. We obtain a tradeoff between the query time and the number of times the index needs to be updated as the points move. We also describe an indexing scheme in which the number of I/Os required to answer a query depends monotonically on the difference between the query time stamp t and the current time. Finally, we develop an efficient indexing scheme to answer approximate nearest-neighbor queries among moving points.
Risk Behavior and Rational Expectations in the U.S. Broiler Market

This study examines the empirical implications of extending the rational expectations hypothesis (REH) to include price uncertainty. A general estimation framework that incorporates both the restrictions on structural parameters and the variance-covariance terms is developed. GARCH time-series processes are used to generate time-varying expectations of both the means and the variances of exogenous variables. The empirical application is with a quarterly model of the U.S. broiler industry; the results indicate that the rational expectation of price variance is an important determinant of broiler supply. A formal test indicates that the restrictions implied by the REH cannot be rejected.
Enantioselective Organocatalytic α-Fluorination of Cyclic Ketones

The first highly enantioselective α-fluorination of ketones using organocatalysis has been accomplished. The long-standing problem of enantioselective ketone α-fluorination via enamine activation has been overcome via high-throughput evaluation of a new library of amine catalysts. The optimal system, a primary amine functionalized Cinchona alkaloid, allows the direct and asymmetric α-fluorination of a variety of carbo- and heterocyclic substrates. Furthermore, this protocol also provides diastereo-, regio-, and chemoselective catalyst control in fluorinations involving complex carbonyl systems.
Application of a Search System and Vapor-Phase Library to Spectral Identification Problems

A recent major advance in the field of gas chromatography/Fourier transform infrared spectrometry is the availability of a search system and digitized vapor phase infrared library. This paper presents the results of the application of this search system to a real-world sample. Examples are shown of correct matches and an incorrect match. Overall, the search performs very well with good quality unknown spectra, but cannot differentiate between a spectrum and background. These results indicate that visual comparison of the unknown and standard are required for all but the most routine identifications.
A convenient synthesis of trialkylalkylidyne tungsten (6+) compounds and the X-ray crystal structure of (Me3CCH2)3WCPh(py)

Abstract A convenient synthesis for trialkylalkylidyne tungsten compounds is reported based on the metathetic reaction between alkyllithium or alkyl-Grignard re
Gamma-ray line astronomy

Recent gamma-ray line observations and their interpretations are reviewed and prospects for future line detections are discussed.
Unbiased Inclination Distributions for Objects in the Kuiper Belt

Using data from the Deep Ecliptic Survey (DES), we investigate the inclination distributions of objects in the Kuiper Belt. We present a derivation for observational bias removal and use this procedure to generate unbiased inclination distributions for Kuiper Belt objects (KBOs) of different DES dynamical classes, with respect to the Kuiper Belt plane. Consistent with previous results, we find that the inclination distribution for all DES KBOs is well fit by the sum of two Gaussians, or a Gaussian plus a generalized Lorentzian, multiplied by sin i. Approximately 80% of KBOs are in the high-inclination grouping. We find that Classical object inclinations are well fit by sin i multiplied by the sum of two Gaussians, with roughly even distribution between Gaussians of widths 2.0+0.6 –0.5° and 8.1+2.6 –2.1°. Objects in different resonances exhibit different inclination distributions. The inclinations of Scattered objects are best matched by sin i multiplied by a single Gaussian that is centered at 19.1+3.9 –3.6° with a width of 6.9+4.1 –2.7°. Centaur inclinations peak just below 20°, with one exceptionally high-inclination object near 80°. The currently observed inclination distribution of the Centaurs is not dissimilar to that of the Scattered Extended KBOs and Jupiter-family comets, but is significantly different from the Classical and Resonant KBOs. While the sample sizes of some dynamical classes are still small, these results should begin to serve as a critical diagnostic for models of solar system evolution.
Chemoenzymatic synthesis of oligosaccharides and glycoproteins

Oligosaccharides are involved in a wide range of biological processes including, for example, bacterial and viral infection, cancer metastasis, the blood-clotting cascade and many other crucial intercellular recognition events. The molecular details of these biological recognition events are, however, not well understood. To express their function, oligosaccharides often occur as glycoconjugates attached to proteins (called glycoproteins) or lipids (called glycolipids) that are often found on the surface of cells. Such physiological relevance has stimulated researchers to make significant advances in oligosaccharide and glycoprotein preparation despite the chemically imposing and polydisperse nature of these molecules. The chemical and Chemoenzymatic methods developed recently have facilitated the synthesis of structurally defined oligosaccharides and glycoconjugates such that a more thorough understanding of their biological function and potential therapeutic application can be addressed.
Spectral reproduction from scene to hardcopy: II. Image processing

Traditional image processing techniques used for 3- and 4- band images are not suited to the many-band character of spectral images. A sparse multi-dimensional lookup table with inter-node interpolation is a typical image processing technique used for applying either a known model or an empirically derived mapping to an image. Such an approach for spectral images becomes problematic because input dimensionality of lookup tables is proportional to the number of source image bands and the size of lookup table sis exponentially related to the number of input dimensions. While an RGB or CMY source images would require a 3D lookup table, a 31-band spectral image would need a 31-dimensional lookup table. A 31-dimensional lookup table would be absurdly large. A novel approach to spectral image processing is explored. This approach combines a low-cost spectral analysis followed by application of one from a set of low-dimensional lookup tables. The method is computationally feasible and does not make excessive demands on disk space or run-time memory.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Voltage Opens Unopposed Gap Junction Hemichannels Formed By A Connexin 32 Mutant Associated With X-Linked Charcot-Marie-Tooth Disease

The X-linked form of Charcot-Marie-Tooth disease (CMTX) is an inherited peripheral neuropathy that arises in patients with mutations in the gene encoding the gap junction protein connexin 32 (Cx32), which is expressed by Schwann cells. We recently showed that Cx32 containing the CMTX-associated mutation, Ser-85-Cys (S85C), forms functional cell-cell channels in paired Xenopus oocytes. Here, we describe that this mutant connexin also shows increased opening of hemichannels in nonjunctional surface membrane. Open hemichannels may damage the cells through loss of ionic gradients and small metabolites and increased influx of Ca2+, and provide a mechanism by which this and other mutant forms of Cx32 may damage cells in which they are expressed. Evidence for open hemichannels includes: (i) oocytes expressing the Cx32(S35C) mutant show greatly increased conductance at inside positive potentials, significantly larger than in oocytes expressing wild-type Cx32 (Cx32WT); and (ii) the induced currents are similar to those previously described for several other connexin hemichannels, and exhibit slowly developing increases with increasing levels of positivity and reversible reduction when intracellular pH is decreased or extracellular Ca2+ concentration is increased. Although increased currents are seen, oocytes expressing Cx32(S35C) have lower levels of the protein in the surface and in total homogenates than do oocytes expressing Cx32WT; thus, under the conditions examined here, hemichannels in the surface membrane formed of the Cx32(S85C) mutant have a higher open probability than hemichannels formed of Cx32WT. This increase in functional hemichannels may damage Schwann cells and ultimately lead to loss of function in peripheral nerves of patients harboring this mutation.