cssi/SciSciGPT-SciSciNet huggingface dataset:
LATENT VARIABLE MODELING IN HETEROGENEOUS POPULATIONS

Common applications of latent variable analysis fail to recognize that data may be obtained from several populations with different sets of parameter values. This article describes the problem and gives an overview of methodology that can address heterogeneity. Artificial examples of mixtures are given, where if the mixture is not recognized, strongly distorted results occur. MIMIC structural modeling is shown to be a useful method for detecting and describing heterogeneity that cannot be handled in regular multiple-group analysis. Other useful methods instead take a random effects approach, describing heterogeneity in terms of random parameter variation across groups. These random effects models connect with emerging methodology for multilevel structural equation modeling of hierarchical data. Examples are drawn from educational achievement testing, psychopathology, and sociology of education. Estimation is carried out by the LISCOMP program.
Application of a Light-Front Coupled Cluster Method

As a test of the new light-front coupled-cluster method in a gauge theory, we apply it to the nonperturbative construction of the dressed-electron state in QED, for an arbitrary covariant gauge, and compute the electron’s anomalous magnetic moment. The construction illustrates the spectator and Fock-sector independence of vertex and self-energy contributions and indicates resolution of the difficulties with uncanceled divergences that plague methods based on Fock-space truncation.
The 1 Teraflops QCDSP computer

Abstract The QCDSP computer (Quantum Chromodynamics on Digital Signal Processors) is an inexpensive, massively parallel computer intended primarily for simulations in lattice gauge theory. Currently, two large QCDSP machines are in full-time use: an 8,192 processor, 0.4 Teraflops machine at Columbia University and an 12,288 processor, 0.6 Teraflops machine at the RIKEN-BNL Research Center at Brookhaven National Laboratory. We describe the design process, architecture, software and current physics projects of these computers.
Computers in structural engineering practice: The issue of quality

Abstract In recent years there have been dramatic changes both in the cost of computing and the ease of access to engineering software. Concomitant with these changes is the immense growth of the number of available engineering computer software products. Such growth in numbers of affordable and easily accessible computers and computer programs has created a particularly difficult dilemma for the average engineer. On the one hand, every engineer can easily afford to become involved with the computer. The well known benefits of higher productivity, the ability to solve more complex problems with greater accuracy, the ability to practice with state-of-the-art techniques of analysis and design, and many others are now affordable by all engineers. On the other hand, however, there are very dangerous problems related to the engineering use of computers. Among these various problems, by far the most potentially dangerous one, and the one which is the most difficult to identify, avoid, or correct, is the problem of lack of engineering software quality and reliability. This dilemma of affordable and easy access to computing versus uncertain and dangerous problems of computer use will be a continuing one for the engineering profession. Since the computer problems can have a detrimental effect on the quality and reliability of engineering, and since the numbers of engineers involved with computers appear now to be growing uncontrollably, it is necessary to establish regular dialogues between professionals which address these issues, which expose the pitfalls, and which provide guidelines for practice that can be used to avoid serious problems.
Gravitational-wave memory revisited: Memory from the merger and recoil of binary black holes

Gravitational-wave memory refers to the permanent displacement of the test masses in an idealized (freely-falling) gravitational-wave interferometer. Inspiraling binaries produce a particularly interesting form of memory—the Christodoulou memory. Although it originates from nonlinear interactions at 2.5 post-Newtonian order, the Christodoulou memory affects the gravitational-wave amplitude at leading (Newtonian) order. Previous calculations have computed this non-oscillatory amplitude correction during the inspiral phase of binary coalescence. Using an "effective-one-body" description calibrated with the results of numerical relativity simulations, the evolution of the memory during the inspiral, merger, and ringdown phases, as well as the memory's final saturation value, are calculated. Using this model for the memory, the prospects for its detection are examined, particularly for supermassive black hole binary coalescences that LISA will detect with high signal-to-noise ratios. Coalescing binary black holes also experience center-of-mass recoil due to the anisotropic emission of gravitational radiation. These recoils can manifest themselves in the gravitational-wave signal in the form of a "linear" memory and a Doppler shift of the quasi-normal-mode frequencies. The prospects for observing these effects are also discussed.
IMPROVING THE MODEL OF EMISSION FROM SPINNING DUST: EFFECTS OF GRAIN WOBBLING AND TRANSIENT SPIN-UP

Observations continue to support the interpretation of the anomalous microwave foreground as electric dipole radiation from spinning dust grains as proposed by Draine & Lazarian. In this paper, we present a refinement of the original model by improving the treatment of a number of physical effects. First, we consider a disk-like grain rotating with angular velocity at an arbitrary angle with respect to the grain symmetry axis (i.e., grain wobbling) and derive the rotational damping and excitation coefficients arising from infrared emission, plasma-grain interactions, and electric dipole emission. The angular velocity distribution and the electric dipole emission spectrum for disk-like grains is calculated using the Langevin equation, for cases both with and without fast internal relaxation. Our results show that for fast internal relaxation, the peak emissivity of spinning dust, compared to earlier studies, increases by a factor of ~2 for the warm neutral medium (WNM), the warm ionized medium (WIM), the cold neutral medium (CNM), and the photodissociation region, and by a factor ~4 for reflection nebulae. The frequency at the emission peak also increases by factors ~1.4 to ~2 for these media. Without internal relaxation, the increase of emissivity is comparable, but the emission spectrum is more extended to higher frequency. The increased emission results from the non-sphericity of grain shape and from the anisotropy in damping and excitation along directions parallel and perpendicular to the grain symmetry axis. Second, we provide a detailed numerical study including transient spin-up of grains by single-ion collisions. The range of grain size in which single-ion collisions are important is identified. The impulses broaden the emission spectrum and increase the peak emissivity for the CNM, WNM, and WIM, although the increases are not as large as those due to the grain wobbling. In addition, we present an improved treatment of rotational excitation and damping by infrared emission.
How Do MNCS Vote in Developing Country Elections

Research on multinational corporations (MNCS) and host government political risk in developing countries has largely ignored local electoral politics, economic policies, and the MNC investment ince...
sp3 C−H Bond Arylation Directed by Amidine Protecting Group: α-Arylation of Pyrrolidines and Piperidines

A new ruthenium-catalyzed direct sp3 C−H to C−C bond transformation is disclosed. Specifically, a method for the α-arylation of cyclic amines, containing either permanent (pyridine, pyrimidine) or removable (amidine) directing groups, is described. This cross-coupling reaction involves heating amine substrates with arylboronate ester at 150 °C in a ketone solvent with a catalytic amount of ruthenium carbonyl [Ru3(CO)12]. Arylboronate esters containing either electron-withdrawing or electron-donating substituents could be efficiently coupled. Heteroarene boronates were also effective donors.
AN XMM-NEWTON SURVEY OF THE SOFT X-RAY BACKGROUND. II. AN ALL-SKY CATALOG OF DIFFUSE O VII AND O VIII EMISSION INTENSITIES

We present an all-sky catalog of diffuse O VII and O VIII line intensities, extracted from archival XMM-Newton observations. This catalog supersedes our previous catalog, which covered the sky between l = 120° and l = 240°. We attempted to reduce the contamination from near-Earth solar wind charge exchange (SWCX) emission by excluding times of high solar wind proton flux from the data. Without this filtering, we were able to extract measurements from 1868 observations. With this filtering, nearly half of the observations became unusable, and only 1003 observations yielded measurements. The O VII and O VIII intensities are typically ~2-11 and 3 photons cm–2 s–1 sr–1 (line unit, L.U.), respectively, although much brighter intensities were also recorded. Our data set includes 217 directions that have been observed multiple times by XMM-Newton. The time variation of the intensities from such directions may be used to constrain SWCX models. The O VII and O VIII intensities typically vary by 5 and 2 L.U. between repeat observations, although several intensity enhancements of >10 L.U. were observed. We compared our measurements with models of the heliospheric and geocoronal SWCX. The heliospheric SWCX intensity is expected to vary with ecliptic latitude and solar cycle. We found that the observed oxygen intensities generally decrease from solar maximum to solar minimum, both at high ecliptic latitudes (which is as expected) and at low ecliptic latitudes (which is not as expected). The geocoronal SWCX intensity is expected to depend on the solar wind proton flux incident on the Earth and on the sightline's path through the magnetosheath. The intensity variations seen in directions that have been observed multiple times are in poor agreement with the predictions of a geocoronal SWCX model. We found that the oxygen lines account for ~40%-50% of the 3/4 keV X-ray background that is not due to unresolved active galactic nuclei, in good agreement with a previous measurement. However, we found that this fraction is not easily explainable by a combination of SWCX emission and emission from hot plasma in the halo. We also examined the correlations between the oxygen intensities and Galactic longitude and latitude. We found that the intensities tend to increase with longitude toward the inner Galaxy, possibly due to an increase in the supernova rate in that direction or the presence of a halo of accreted material centered on the Galactic center. The variation of intensity with Galactic latitude differs in different octants of the sky, and cannot be explained by a single simple plane-parallel or constant-intensity halo model.
A Young Planetary Nebula with OH Molecules: NGC 6302

We report the results of a sensitive survey of planetary nebulae in all four ground state OH lines. Our results confirm that evolved planetary nebulae are not OH sources in general. However, we did detect one interesting object: an OH 1612 MHz maser in the young planetary nebula NGC 6302. This nebula may be in a brief evolutionary stage, similar to the young and compact planetary nebula Vy 2-2 where OH has already been detected.
Investigation of acoustic streaming patterns around oscillating sharp edges

Oscillating sharp edges have been employed to achieve rapid and homogeneous mixing in microchannels using acoustic streaming. Here, we used a perturbation approach to study the flow around oscillating sharp edges in a microchannel. This work extends prior experimental studies to numerically characterize the effect of various parameters on the acoustically induced flow. Our numerical results match well with the experimental results. We investigated multiple device parameters such as the tip angle, oscillation amplitude, and channel dimensions. Our results indicate that, due to the inherent nonlinearity of acoustic streaming, the channel dimensions could significantly impact the flow patterns and device performance.
Gradient Estimates for Parabolic and Elliptic Systems from Linear Laminates

We establish several gradient estimates for second-order divergence type parabolic and elliptic systems. The coefficients and data are assumed to be Holder or Dini continuous in the time variable and all but one spatial variable. This type of system arises from the problems of linearly elastic laminates and composite materials. For the proof, we use Campanato’s approach in a novel way. Non-divergence type equations under similar conditions are also discussed.
A β-lactone-based route to cyclopentanes via intramolecular allylsilane additions. An unexpected friedel-crafts alkylation

Abstract Lewis acid promoted intramolecular additions of allylsilanes to β-lactones proceed smoothly to give variously substituted cyclopentanes. A proposed transition state assembly for this reaction guided our efforts to improve the stereoselectivity. A novel Friedel-Crafts alkylation of β-lactones is also described.
Calculations of Doppler Radar Velocity Spectrum Parameters for a Mixture of Rain and Hail

Abstract The radar reflectivity factors, the reflectivity-weighted mean terminal velocities (VT), and the standard deviations (σv) of the resulting Doppler spectra, were computed for specified size distributions of rain, dry and wet ice spheres (taken to be hailstones), and rain with hail. Unambigous estimates of the mean velocity and standard deviation can be obtained from a radar measurement of reflectivity for rain alone and for dry ice spheres as a function of maximum sphere size. The results for wet ice spheres are strongly dependent on the thickness of the liquid water coating on the ice core. When rain and hail coexist, large values of reflectivity are associated with large ranges of VT and σv. If the shape of the hail size distribution is known, an independent measurement of the maximum hailstone diameter or a knowledge of the standard deviation of the observed Doppler velocity spectrum can reduce the uncertainty in estimates of VVT.
Electron-temperature dependence of dissociative recombination of electrons with CO(+)-(CO)n-series ions

The dependence on electron temperature of the coefficients for electron recombination with molecular cluster ions of the carbon monoxide series, CO(+).(CO)n, is determined. A microwave discharge lasting approximately 0.1 msec was applied in 5-20 Torr neon containing a few tenths percent CO in an afterglow mass spectrometer apparatus, and the time histories of the various afterglow ions were measured. Expressions for the dependence of the recombination coefficients of the dimer and trimer ions CO(+).CO and CO(+).(CO)2 are obtained which are found to be significantly different from those previously obtained for hydronium and ammonium series polar cluster ions, but similar to those of simple diatomic ions.
Regional climate models downscaling in the Alpine area with multimodel superensemble

Abstract. The climatic scenarios show a strong signal of warming in the Alpine area already for the mid-XXI century. The climate simulations, however, even when obtained with regional climate models (RCMs), are affected by strong errors when compared with observations, due both to their difficulties in representing the complex orography of the Alps and to limitations in their physical parametrization. Therefore, the aim of this work is to reduce these model biases by using a specific post processing statistic technique, in order to obtain a more suitable projection of climate change scenarios in the Alpine area. For our purposes we used a selection of regional climate models (RCMs) runs which were developed in the framework of the ENSEMBLES project. They were carefully chosen with the aim to maximise the variety of leading global climate models and of the RCMs themselves, calculated on the SRES scenario A1B. The reference observations for the greater Alpine area were extracted from the European dataset E-OBS (produced by the ENSEMBLES project), which have an available resolution of 25 km. For the study area of Piedmont daily temperature and precipitation observations (covering the period from 1957 to the present) were carefully gridded on a 14 km grid over Piedmont region through the use of an optimal interpolation technique. Hence, we applied the multimodel superensemble technique to temperature fields, reducing the high biases of RCMs temperature field compared to observations in the control period. We also proposed the application of a brand new probabilistic multimodel superensemble dressing technique, already applied to weather forecast models successfully, to RCMS: the aim was to estimate precipitation fields, with careful description of precipitation probability density functions conditioned to the model outputs. This technique allowed for reducing the strong precipitation overestimation, arising from the use of RCMs, over the Alpine chain and to reproduce well the monthly behaviour of precipitation in the control period.
Synthesis of nucleoside methylphosphonothioates

Abstract Deoxydinucleotide methylphosphonothioates containing 5′-5′ and 3′-5′ internucleotide linkages were synthesized regioselectively from nucleosides and methylphosphonothioic dichloride by successive displacement of chlorine atoms. The diastereomers were resolved by hplc.
Dioxygen and water activation processes on multi-Ru-substituted polyoxometalates: comparison with the "blue-dimer" water oxidation catalyst.

Dioxygen and water activation on multi-Ru-substituted polyoxometalates were studied using the B3LYP density functional method. It was shown that the reaction of the Ru2-substituted γ-Keggin polyoxotungstate {γ-[(H2O)RuIII−(μ-OH)2−RuIII(H2O)][SiW10O36]}4−, I(H2O), with O2 is a 4-electron highly exothermic [ΔEgas = 62.5 (ΔEgas + ΔGsolv(water) = 24.6) kcal/mol] process and leads to formation of (H2O){γ-[(O)Ru−(μ-OH)2−Ru(O)](H2O)[SiW10O36]}4−, IV(H2O). Both the stepwise (or dissociative) and the concerted (or associative) pathways of this reaction occurring with and without water dissociation, respectively, were examined, and the latter has been found to be kinetically more favorable. It was shown that the first 1e-oxidation is achieved by the H2O-to-O2 substitution, which might occur with a maximum of 23.1 (10.5) kcal/mol barrier and leads to the formation of {γ-[(OO)Ru−(μ-OH)2−Ru(H2O)](H2O)[SiW10O36]}4−, II(H2O). The second 1e-oxidation is initiated by the proton transfer from the coordinated water molecule...
Stereoselective Synthesis of Cyclic Ethers via the Palladium-Catalyzed Intramolecular Addition of Alcohols to Phosphono Allylic Carbonates

Cross metathesis of the acrolein-derived phosphono allylic carbonate and hydroxy alkenes using second generation Grubbs catalyst and copper(I) iodide gave the substituted phosphonates in good yield. Stereospecific palladium(0)-catalyzed cyclization gave tetrahydrofuran and tetrahydropyran vinyl phosphonates. Regioselective Wacker oxidation of the vinyl phosphonate gave the beta-keto phosphonate, which underwent HWE reaction with benzaldehyde to yield the unsaturated ketone. The utility of the cross metathesis/cyclization protocol was further demonstrated by a formal synthesis of centrolobine.
The L^p Dirichlet problem for elliptic systems on Lipschitz domains

We develop a new approach to the $L^p$ Dirichlet problem via $L^2$ estimates and reverse Holder inequalities. We apply this approach to second order elliptic systems and the polyharmonic equation on a bounded Lipschitz domain $\Omega$ in $R^n$. For $n\ge 4$ and $2-\epsilon<p<2(n-1)/(n-3)+\epsilon$, we establish the solvability of the Dirichlet problem with boundary value data in $L^p(\partial\Omega)$. In the case of the polyharmonic equation $\Delta^{\ell}u=0$ with $\ell\ge 2$, the range of $p$ is sharp if $4\le n \le 2\ell +1$.
Numerical Schemes for the Hamilton-Jacobi and Level Set Equations on Triangulated Domains

Borrowing from techniques developed for conservation law equations, numerical schemes which discretize the Hamilton?Jacobi (H-J), level set, and Eikonal equations on triangulated domains are presented. The first scheme is a provably monotone discretization for the H-J equations. Unfortunately, the basic scheme lacks Lipschitz continuity of the numerical Hamiltonian. By employing a “virtual” edge flipping technique, local Lipschitz continuity of the numerical flux is restored on acute triangulations. Next, schemes are introduced and developed based on the weaker concept of positive coefficient approximations for homogeneous Hamiltonians. These schemes possess a discrete maximum principle on arbitrary triangulations and exhibit local Lipschitz continuity of the numerical Hamiltonian. Finally, a class of Petrov?Galerkin approximations is considered. These schemes are stabilized via a least-squares bilinear form. The Petrov?Galerkin schemes do not possess a discrete maximum principle but generalize to high order accuracy. Discretization of the level set equation also requires the numerical approximation of a mean curvature term. A simple mass-lumped Galerkin approximation is presented in Section 6 and analyzed using maximum principle analysis. The use of unstructured meshes permits several forms of mesh adaptation which have been incorporated into numerical examples. These numerical examples include discretizations of convex and nonconvex forms of the H-J equation, the Eikonal equation, and the level set equation.
Jet quenching in thin quark–gluon plasmas I: formalism

The modification and amplification of the gluon angular distribution produced along with hard jets in nuclear collisions is computed. We consider the limit of a thin quark-gluon plasma, where the number of rescatterings of the jet and gluons is small. The focus is on jet quenching associated with the formation of highly off-shell partons in hard scattering events involving nuclei. The interference between the initial hard radiation amplitude, the multiple induced Gunion-Bertsch radiation amplitudes, and gluon rescattering amplitudes leads to an angular distribution that differs considerably from both the standard DGLAP evolution and from the classical limit parton cascading. The cases of a single and double rescattering are considered in detail, and a systematic method to compute all matrix elements for the general case is developed. A simple power law scaling of the angular distribution with increasing number of rescatterings is found and used for estimates of the fractional energy loss as a function of the plasma thickness.
A finite element procedure for plates with curved boundaries

Abstract The difficulties associated with the use of the finite element method on regions with curved boundaries are discussed. An approach based on the Lagrangian multiplier technique is presented which overcomes all of the difficulties mentioned and which is of particular value for higher order problems such as plate bending. The method is tested numerically using a refined triangular plate element and is found to be a significant improvement over more conventional finite element methods, for this class of problems.
A Trace Bound for the Hereditary Discrepancy

Let A be the incidence matrix of a set system with m sets and n points, m ≤ n , and let t= \mathop \rm tr M , where M= A T A . Finally, let ? = \mathop \rm tr M 2 be the sum of squares of the elements of M . We prove that the hereditary discrepancy of the set system is at least ${\frac14}\, c^{n\sigma/ t^2} \sqrt{t/n}$, with $c= \frac{1}{324}$ . This general trace bound allows us to resolve discrepancy-type questions for which spectral methods had previously failed. Also, by using this result in conjunction with the spectral lemma for linear circuits, we derive new complexity bounds for range searching. We show that the (red--blue) discrepancy of the set system formed by n points and n lines in the plane is Ω(n 1/6 ) in the worst case and always 1 \tilde O(n 1/6 ) . We give a simple explicit construction of n points and n halfplanes with hereditary discrepancy \tildeΩ(n 1/4 ) . We show that in any dimension d= Ω( log n/\kern -1ptlog log n ) , there is a set system of n points and n axis-parallel boxes in \bf R d with discrepancy n Ω(1/\kern -1pt log log n) . Applying these discrepancy results together with a new variation of the spectral lemma, we derive a lower bound of Ω(nlog n) on the arithmetic complexity of off-line range searching for points and lines (for nonmonotone circuits). We also prove a lower bound of Ω(nlog n/\kern -1ptlog log n) on the complexity of orthogonal range searching in any dimension Ω(log n/\kern -1ptlog log n) . 1 We use the notation \tilde O(m) and \tilde Ω(m) as shorthand for O(mlog c m) and Ω(m/\kern -1ptlog c m) , respectively, for some constant c>0 .
A Polymer-Supported Phosphazine as a Stable and Practical Reagent in the Three-Component Synthesis of Substituted (Cyclopentadienyl)tricarbonylrhenium Complexes.

A very stable heterogenized difunctional cyclopentadienyl-ring precursor, storable under ambient conditions, readily participates in the simultaneous formation of a η5 bond with a [fac-Re(CO)3 ]+ species and a σ bond with heteroatom (halides, carboxylates) or carbon nucleophiles (boronic acids) to produce halo-, acyloxy-, or carbon-substituted cyclopentadienyl-Re(CO)3 complexes in a one-pot reaction in yields of between 41 and 71 % [Eq. (1)]. No catalyst is required and unprotected (usually) sensitive functional groups are well tolerated.
Pyrazole Synthesis Using a Titanium‐Catalyzed Multicomponent Coupling Reaction and Synthesis of Withasomnine

The titanium-catalyzed 3-component coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provide pyrazoles. Seventeen examples of pyrazoles are provided using this one-pot, 4-component procedure from simple starting materials. The regioselectivity of the alkyne addition can be controlled in some cases with catalyst architecture, and regioselectivity of monosubsituted hydrazines to unsymmetrical 1,3-diimines is discussed. This multicomponent coupling strategy was applied to the synthesis of withasomnine in an efficient procedure, which gave the natural product in 24% overall yield from 4-pentyn-1-ol.
Structural Effects of the Cyclobutyl Group on Reactivity and Properties

1 Alkyl and Cycloalkyl Groups 2 The Nature of Structural Effects 3 Electrical Effects 4 Steric Effects 5 Intermolecular Forces 6 Applications 7 An Overview of Alkyl and Cycloalkyl Substituent and Structural Effects 8 The Cyclobutyl and Related Groups as Substituents 9 The Cyclobutyl and Related Groups as Skeletal Groups. The Transmission of Delocalized Electrical Effects 10 Appendix I. Glossary 11 Appendix II. Abbreviationsa Keywords: cyclobutyl group on reactivity and properties; structure–property relationships (SPR); structure–property quantitative relationships (SPQR); Quantitative structure–physical property relationships (QSPR); Kehrmann and steric effects concept; monoparametric model of steric effects; intermolecular forces; cyclobutane derivative data set correlation analysis application
Regio- and Stereoselective Synthesis of Alkyl Allylic Ethers via Gold(I)-Catalyzed Intermolecular Hydroalkoxylation of Allenes with Alcohols

Reaction of 1-phenyl-1,2-butadiene with 2-phenyl-1-ethanol catalyzed by a 1:1 mixture of a gold(I) N-heterocyclic carbene complex and AgOTf at room temperature for 1 h led to isolation of (E)-(3-phenethoxy-1-butenyl)benzene in 96% yield as a single regio- and stereoisomer. Gold(I)-catalyzed intermolecular allene hydroalkoxylation was effective for monosubsituted, 1,1- and 1,3-disubstituted, trisubstituted, and tetrasubstituted allenes and for a range of primary and secondary alcohols, methanol, phenol, and propionic acid.
Precision Tests of Quantum Mechanics

It is proposed to set stringent limits on possible nonlinear corrections to ordinary quantum mechanics by searching for the detuning of resonant transitions. A suggested nonlinear generalization of quantum mechanics is used to show that such detuning would be expected in the rf transition in $^{9}\mathrm{Be}^{+}$ ions that is used to set frequency standards. Measurements at the National Bureau of Standards already set limits of order ${10}^{\ensuremath{-}21}$ on the fraction of the energy of the $^{9}\mathrm{Be}$ nucleus that could be due to nonlinear corrections to quantum mechanics, with good prospects of improving this by 2-3 orders of magnitude.
Modulation-free laser frequency stabilization and detuning

We have developed a modulation-free technique for stabilizing a laser to a Doppler-free saturated absorption spectrometer without the need for phase sensitive detection. By using two acousto-optic modulators, we can lock, with variable offset, to atomic resonances. The new technique works equally well with both vapor and discharge reference cells. We demonstrate the technique using rubidium and metastable argon as references.
Actionable Recommendations in the Bright Futures Child Health Supervision Guidelines

Background: With the growing use of electronic health record systems, there is a demand for an electronic version of the leading American pediatric preventive care guideline, Bright Futures. As computer implementation requires actionable recommendations, it is important to assess to what degree Bright Futures meets criteria for actionability. Objectives: We aimed to 1) determine the number of actionable recommendations in the current edition of Bright Futures and 2) to recommend a specific format for representing an important class of guidelines in a way that better facilitates computer implementation. Methods: We consolidated all action statements in Bright Futures into recommendations. We then used two dimensions (decidability and executability) in the Guideline Implementability Appraisal v 2.0 (GLIA) to determine the actionability of the recommendations. Decidability means the recommendation states precisely under what conditions to perform those actions. Executability means actions are stated specifically, unambiguously and in sufficient detail. The results were presented in a figure titled Service Interval Diagram (SID), describing actionable recommendations, age intervals during which they are applicable, and how frequently they should occur in that interval. Results: We consolidated 2161 action items into 245 recommendations and identified 52 that were actionable (21%). Almost exclusively, these recommendations addressed screening, such as newborn metabolic screening, or child safety, such as car seat use. A limited number (n=13) of recommendations for other areas of anticipatory guidance were also actionable. No recommendations on child discipline, family function or mental health met our criteria for actionability. The SID representing these recommendations is presented in a figure. Conclusion: Only a portion of the Bright Futures Guidelines meets criteria for actionability. Substantial work lies ahead to develop most recommendations for anticipatory guidance into a computer implementable format.
A general diagnostic model applied to language testing data

Probabilistic models with one or more latent variables are designed to report on a corresponding number of skills or cognitive attributes. Multidimensional skill profiles offer additional information beyond what a single test score can provide, if the reported skills can be identified and distinguished reliably. Many recent approaches to skill profile models are limited to dichotomous data and have made use of computationally intensive estimation methods such as Markov chain Monte Carlo, since standard maximum likelihood (ML) estimation techniques were deemed infeasible. This paper presents a general diagnostic model (GDM) that can be estimated with standard ML techniques and applies to polytomous response variables as well as to skills with two or more proficiency levels. The paper uses one member of a larger class of diagnostic models, a compensatory diagnostic model for dichotomous and partial credit data. Many well-known models, such as univariate and multivariate versions of the Rasch model and the two-parameter logistic item response theory model, the generalized partial credit model, as well as a variety of skill profile models, are special cases of this GDM. In addition to an introduction to this model, the paper presents a parameter recovery study using simulated data and an application to real data from the field test for TOEFL Internet-based testing.
Polyfunctional cubic silsesquioxanes as building blocks for organic/inorganic hybrids

Cubic silsesquioxanes, [RSiO1.5]x, potentially offer access to organic/inorganic hybrids wherein the exact shape, size and mechanical properties of the inorganic component are perfectly defined. Furthermore, by tailoring the organic functionality bound to silicon, the inorganic/ organic interface can also be perfectly defined. Finally, careful selection of the polymerizable groups in the organic moieties can provide goodto-excellent control of the crosslinked density or degree of polymerization of the resulting hybrid materials. Thus, cubic silsesquioxanes may be exceptional model materials for inorganic/organic hybrids. Methods of synthesizing cubes with liquid-crystalline and/or polymerizable organic moieties are described. Some thermal properties are discussed. The catalytic copolymerization of the octavinyldimethylsiloxy-functionalized cube with the octahydridodimethylsiloxy-functionalized cube to produce a material with well-defined microporosity and high surface area is described. # 1998 John Wiley & Sons, Ltd.
Dynamics of a producer-freeloader ecosystem on the brink of collapse

Ecosystems may irreversibly change after perturbations once the tipping point is reached. Here, the authors assess the dynamics of an experimental ecosystem on the brink of collapse and find that the producer populations grow in size as the environment deteriorates, but the collective dynamics slows down near the tipping point.
Symplectic geometry and the uniqueness of Grauert tubes

A compact real analytic Riemannian manifold M admits a canonical complexification with plurisubharmonic exhaustion function satisfying the homogeneous complex Monge-Ampere equation, called a Grauert tube. From the point of view of complex analysis, several authors have considered whether a given complex manifold can arise in more than one way from this construction. We show that given a compact M and a finite exhaustion, the underlying Riemannian structure is unique. The proof uses the technique of holomorphic disks spanning two exact Lagrangian submanifolds of the cotangent bundle of M, and Schwarz reflection.
Rapid synthesis of etherimides via catalytic arylation of silylated phenols

Abstract We report here a rapid and efficient method for the synthesis of aromatic etherimides from silylated phenols and 4-fluorophthalimides catalyzed by CsF. Reaction times are a few minutes and products are easily purified requiring no column chromatography.
Further measurements of the rotational spectrum of COF2: Improved molecular constants for the ground and ν2 states

Abstract Additional measurements of the rotational spectrum of COF2 in the 200–600 GHz region have led to improved rotational parameters for the ground vibrational state. These parameters have been used in refitting the ν2 infrared spectrum near 963 cm−1. Results using both Ir A and IIIr S Watson reduced Hamiltonians are presented. The new upper state parameters reproduce recently measured FIR laser frequencies with an RMS of 0.25 MHz.
Efficient Microwave-assisted One-pot Three-component Synthesis of 2,3-Disubstituted Benzofurans under Sonogashira Conditions

An efficient one-pot method for the synthesis of 2,3-disubstituted benzo[b]furans from commercially available 2-iodophenols, terminal acetylenes and aryl iodides has been developed utilizing Sonogashira reaction conditions. After an initial Sonogashira coupling of the 2-iodophenol with the terminal alkyne, cyclization involving the aryl iodide provides the 2,3-disubstituted benzo[b]furan in good to excellent yields. The use of microwave irradiation shortens the reaction times and minimizes the side products. This methodology is especially useful for the construction of libraries of highly substituted benzo[b]furans and their analogues.
Detachable Object Detection: Segmentation and Depth Ordering from Short-Baseline Video

We describe an approach for segmenting a moving image into regions that correspond to surfaces in the scene that are partially surrounded by the medium. It integrates both appearance and motion statistics into a cost functional that is seeded with occluded regions and minimized efficiently by solving a linear programming problem. Where a short observation time is insufficient to determine whether the object is detachable, the results of the minimization can be used to seed a more costly optimization based on a longer sequence of video data. The result is an entirely unsupervised scheme to detect and segment an arbitrary and unknown number of objects. We test our scheme to highlight the potential, as well as limitations, of our approach.
MULTIPACTOR DISCHARGE ON A DIELECTRIC

This paper proposes a novel theory of single-surface multipactor discharge on a dielectric, such as an rf window. Using a Monte Carlo simulation, we obtain the susceptibility diagram, applicable to a wide range of materials, in terms of the rf electric field and of the dc electric field that may result from dielectric charging. The electron multiplication mechanism assumes realistic yield curves of secondary electrons, including distributions of emission velocities and angles for these electrons. The susceptibility diagram thus constructed allows an immediate assessment of the range of rf power over which multipactor may be expected to occur. A simple analytic theory is constructed to explain the simulation results.
Polarization and localization in insulators: Generating function approach

We develop the theory and practical expressions for the full quantum-mechanical distribution of the intrinsic macroscopic polarization of an insulator in terms of the ground state wave function. The central quantity is a cumulant generating function, which yields, upon successive differentiation, all the cumulants and moments of the probability distribution of the center of mass $\mathbf{X}/N$ of the electrons, defined appropriately to remain valid for extended systems obeying twisted boundary conditions. The first moment is the average polarization, where we recover the well-known Berry phase expression. The second cumulant gives the mean-square fluctuation of the polarization, which defines an electronic localization length ${\ensuremath{\xi}}_{i}$ along each direction i: ${\ensuremath{\xi}}_{i}^{2}=(〈{X}_{i}^{2}〉\ensuremath{-}〈{X}_{i}{〉}^{2})/N.$ It follows from the fluctuation-dissipation theorem that in the thermodynamic limit ${\ensuremath{\xi}}_{i}$ diverges for metals and is a finite, measurable quantity for insulators. In noninteracting systems ${\ensuremath{\xi}}_{i}^{2}$ is related to the spread of the Wannier functions. It is possible to define for correlated insulators maximally localized ``many-body Wannier functions,'' which for large N become localized in disconnected regions of the high-dimensional configuration space, establishing a direct connection with Kohn's theory of the insulating state. Interestingly, the expression for ${\ensuremath{\xi}}_{i}^{2},$ which involves the second derivative of the wave function with respect to the boundary conditions, is directly analogous to Kohn's formula for the ``Drude weight'' as the second derivative of the energy.
Etching of silicon in fluoride solutions

Abstract The development and status of what is commonly called the Gerischer mechanism of silicon etching in fluoride solutions is reviewed. The two most widely used and studied wet etchants of silicon are F − and OH − . Their mechanisms of atom removal share many things in common; in particular, chemical passivation by a hydrogen-terminated surface plays an important role in both. Crucially, however, their initiation steps are different, and this leads to important differences in the structures of the materials produced by the etchants. The initiation of etching by F − is electrochemical in nature, responding to the electronic structure of the Si, and is, therefore, a self-limiting reaction that can produce nanocrystalline porous silicon. Hydroxide etching destroys porous silicon because its initiation step is a catalytic chemical reaction and not a self-limiting process. A number of unanswered questions regarding the dynamics of fluoride etching are highlighted.
A Spreading Layer Origin for Dwarf Nova Oscillations

Dwarf nova outbursts often show coherent (Q ~ 104-106) sinusoidal oscillations with the largest pulsed fraction in the extreme ultraviolet. Called dwarf nova oscillations (DNOs), they have periods of P ≈ 3-40 s and scale with luminosity as P ∝ L-β with β ≈ 0.1-0.2. We propose that DNOs may be produced by nonradial oscillations in a thin hydrostatic layer of freshly accreted material, the "spreading layer" (SL), at the white dwarf (WD) equator. This would naturally explain a number of key properties of DNOs, including their frequency range, sinusoidal nature, sensitivity to accretion rate, and why they are only seen during outburst. In support of this hypothesis, we construct a simple model that treats the SL as a cavity containing shallow surface waves, each with the same radial structure, but split into three different modes denoted by their azimuthal wavenumber, m. The m = 0 latitudinally propagating mode best matches the periods and scalings associated with most DNOs, and DNOs with periods shorter than the WD Keplerian period are explained by the m = -1 prograde mode. We also predict a third set of oscillations, produced by the m = 1 retrograde mode, and show its expected dependence on accretion rate.
Laser phase noise effects on the dynamics of optomechanical resonators

We investigate theoretically the influence of laser phase noise on the cooling and heating of a generic cavity optomechanical system. We derive the back-action damping and heating rates and the mechanical frequency shift of the radiation-pressure-driven oscillating mirror, and derive the minimum phonon occupation number for small laser linewidths. We find that, in practice, laser phase noise does not pose serious limitations to ground-state cooling. Additionally, we explore the regime of parametric amplification where coherent oscillations of the mirror are realizable. It is found that heating from laser phase noise is of significance and can cause the onset of instabilities. We then consider the effects of laser phase noise in a parametric cavity driving scheme that minimizes the back-action heating of one of the quadratures of the mechanical oscillator motion. Laser linewidths, narrow compared to the decay rate of the cavity field, do not pose any significant problems in an experimental setting, but broader linewidths limit the practicality of this back-action evasion method.
Panic-prone state induced in rats with GABA dysfunction in the dorsomedial hypothalamus is mediated by NMDA receptors

Rats with chronic inhibition of GABA synthesis and consequently enhanced glutamatergic excitation in the dorsomedial hypothalamus (DMH) develop panic-like responses, defined as tachycardia, tachypnea, hypertension, and increased anxiety as measured by a social interaction (SI) test, after intravenous sodium lactate infusions, a phenomenon similar to patients with panic disorder. Therefore, the present studies tested the role of the postsynaptic NMDA and AMPA type glutamatergic receptors in the lactate-induced panic-like responses in these rats. Rats were fit with femoral arterial and venous catheters and Alzet pumps [filled with the GABA synthesis inhibitor L-allylglycine (L-AG; 3.5 nmol/0.5 microl per hour) or its inactive isomer D-AG] into the DMH. After 4-5 d of recovery only those rats with L-AG pumps exhibited panic-like responses to lactate infusions. Using double immunocytochemistry, we found that rats exhibiting panic-like responses (e.g., L-AG plus lactate) had increased c-Fos immunoreactivity in DMH neurons expressing the NMDA receptor 1 (NR1) subunit, but not those expressing the glutamate receptor 2 and 3 subunits of the AMPA receptors. To confirm this pharmacologically, we tested another group of rats implanted with l-AG pumps with intravenous lactate infusions preceded by injections of either NMDA [aminophosphonopentanoic acid (AP-5) or (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d]cyclohepten-5,10-imine maleate (MK-801)] or non-NMDA [CNQX or 4-(8-methyl-9H-1,3-dioxolo[4,5-h][2,3]benzodazepin-5-yl)-benzenamine dihydrochloride (GYKI52466)] antagonists into the DMH. Injections of NMDA, but not non-NMDA, antagonists into the DMH resulted in dose-dependent blockade of the tachycardia, tachypnea, hypertension, and SI responses after lactate infusions. These results suggest that NMDA, and not non-NMDA, type glutamate receptors regulate lactate-induced panic-like responses in rats with GABA dysfunction in the DMH.
Resolvents of Elliptic Boundary Problems on Conic Manifolds

We prove the existence of sectors of minimal growth for realizations of boundary value problems on conic manifolds under natural ellipticity conditions. Special attention is devoted to the clarification of the analytic structure of the resolvent.
Correlation functions of the Schur process through Macdonald difference operators

Introduced by Okounkov and Reshetikhin, the Schur process is known to be a determinantal point process, meaning that its correlation functions are minors of a single correlation kernel matrix. Previously, this was derived using determinantal expressions for the skew-Schur polynomials. In this paper we obtain this result in a different way, using the fact that the Schur polynomials are eigenfunctions of Macdonald difference operators.
Experimental Analysis of Link Estimation Methods in Low Power Wireless Networks

Abstract Wireless sensor networks are envisioned to be an integral part of cyber-physical systems, yet wireless networks are inherently dynamic and come with various uncertainties. One such uncertainty is wireless communication itself which assumes complex spatial and temporal dynamics. For dependable and predictable performance, therefore, link estimation has become a basic element of wireless network routing. Several approaches using broadcast beacons and/or unicast MAC feedback have been proposed in the past years, but there is still no systematic characterization of the drawbacks and sources of errors in beacon-based link estimation in low-power wireless networks, which leads to ad hoc usage of beacons in routing. Using a testbed of 98 XSM motes (an enhanced version of MICA2 motes), we characterize the negative impact that link layer retransmission and traffic-induced interference have on the accuracy of beacon-based link estimation, and we show that data-driven link estimation and routing achieve higher event reliability (e.g., by up to 18.75%) and transmission efficiency (e.g., by up to a factor of 1.96) than beacon-based approaches. These findings provide solid evidence for the necessity of data-driven link estimation and demonstrate the importance of addressing the drawbacks of beacon-based link estimation when designing protocols for low-power wireless networks of cyber-physical systems.