cssi/SciSciGPT-SciSciNet huggingface dataset:
Honeypot back-propagation for mitigating spoofing distributed Denial-of-Service attacks

The Denial-of-Service (DoS) attack is a challenging problem in the current Internet. Many schemes have been proposed to trace spoofed (forged) attack packets back to their sources. Among them, hop-by-hop schemes are less vulnerable to router compromise than packet marking schemes, but they require accurate attack signatures, high storage or bandwidth overhead, and cooperation of many ISPs. In this paper, we propose honeypot back-propagation, an efficient hop-by-hop traceback mechanism, in which accurate attack signatures are obtained by a novel leverage of the roaming honeypots scheme. The reception of attack packets by a roaming honeypot (a decoy machine camouflaged within a server pool) triggers the activation of a tree of honeypot sessions rooted at the honeypot under attack toward attack sources. The tree is formed hierarchically, first at Autonomous system (AS) level and then at router level. Honeypot back-propagation supports incremental deployment by providing incentives for ISPs even with partial deployment. Against low-rate attackers, most traceback schemes would take a long time to collect the needed number of packets. To address this problem, we also propose progressive back-propagation to handle low-rate attacks, such as on-off attacks with short bursts. Analytical and simulation results demonstrate the effectiveness of the proposed schemes under a variety of DDoS attack scenarios.
Highly Enantioselective Direct Alkylation of Arylacetic Acids with Chiral Lithium Amides as Traceless Auxiliaries

A direct, highly enantioselective alkylation of arylacetic acids via enediolates using a readily available chiral lithium amide as a stereodirecting reagent has been developed. This approach circumvents the traditional attachment and removal of chiral auxiliaries used currently for this type of transformation. The protocol is operationally simple, and the chiral reagent is readily recoverable.
Ignition on the National Ignition Facility

The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and experiments studying high energy density (HED) science, is nearing completion at Lawrence Livermore National Laboratory (LLNL). NIF is a 192-beam Nd-glass laser facility that will produce 1.8 MJ, 500 TW of ultraviolet light, making it over fifty times more energetic than present ICF facilities. The NIF Project, begun in 1995, is over 90% complete and is scheduled for completion in 2009. The building and the entire beam path have been completed. The Project is presently installing the optics and electronics to build out the beams and is commissioning them in the laser bays. By September 2007, all of the lasers in one of the two laser bays will be commissioned with the capability of producing over 2 MJ of 1ω (1.05 μm) light, making NIF the world's first mega Joule laser system. A year later, the laser system will be essentially complete. Experiments using one beam in the Precision Diagnostic System (PDS) have shown that NIF can meet all of its 3ω light performance goals including energy, power, focusing, and shot rate and has the precision and accuracy required for ignition pulse performance. The plan is to have half of the beams commissioned to the target chamber in a symmetric geometry to begin 96-beam symmetric indirect-drive experiments. These first ICF experiments using more than 200 kJ of 3ω light will have an order of magnitude more energy than presently available and represent the beginning of experiments preparing for ignition. This national effort for ignition experiments is coordinated through a detailed plan called the National Ignition Campaign (NIC) that includes the science, technology, and equipment such as diagnostics, cryogenic target manipulator, and user optics required for ignition experiments. The goal is to have all of the equipment operational and integrated into the facility soon after Project completion to begin ignition experiments in 2010. In addition, experiments will begin to investigate HED science for defense and basic science applications. With over 50 times more energy than present facilities and the ability to produce ignition, NIF will explore new physics regimes. Following project completion in 2009, facility time at NIF will be allocated to the broad user community using the process outlined in a formal governance plan. A NIF User Office has been established to coordinate use of NIF by the national security and other user communities.
Topological entropy of DNA sequences

Motivation: Topological entropy has been one of the most difficult to implement of all the entropy-theoretic notions. This is primarily due to finite sample effects and high-dimensionality problems. In particular, topological entropy has been implemented in previous literature to conclude that entropy of exons is higher than of introns, thus implying that exons are more ‘random’ than introns. Results: We define a new approximation to topological entropy free from the aforementioned difficulties. We compute its expected value and apply this definition to the intron and exon regions of the human genome to observe that as expected, the entropy of introns are significantly higher than that of exons. We also find that introns are less random than expected: their entropy is lower than the computed expected value. We also observe the perplexing phenomena that introns on chromosome Y have atypically low and bimodal entropy, possibly corresponding to random sequences (high entropy) and sequences that posses hidden structure or function (low entropy). Availability: A Mathematica implementation is available at http://www.math.psu.edu/koslicki/entropy.nb Contact: koslicki@math.psu.edu Supplementary information:Supplementary data are available at Bioinformatics online.
Work-hardening and effective viscosity in solid beryllium

Abstract Results from Hopkinson split-bar, plate-impact, and cylinder deceleration experiments on beryllium are compared with hydrodynamic computer code simulations. By substantially increasing the beryllium work-hardening in the Steinberg-Guinan constitutive model, excellent agreement between the experiments and the calculations is achieved. A model to estimate effective viscosity is also proposed and the resultant calculations are in reasonable agreement with those derived from another model advanced by Asay, Chhabildas and Wise.
Calibrated surfaces and supersymmetric Wilson loops

We study the dual gravity description of supersymmetric Wilson loops whose expectation value is unity. They are described by calibrated surfaces that end on the boundary of anti de-Sitter space and are pseudo-holomorphic with respect to an almost complex structure on an eight-dimensional slice of AdS5 × S5. The regularized area of these surfaces vanishes, in agreement with field theory non-renormalization theorems for the corresponding operators.
500 – 3200 Å observations of the interacting binary stars V356 Sgr and β Lyr

In this paper we present new results from the Voyager ultraviolet spectrometers and the IUE spacecraft on V356 Sgr and β Lyr. The V356 Sgr observations cover, in detail, two eclipses and include one IUE high dispersion SWP image. During both eclipses the total strength of the UV emission lines were found to be invariant. Also, an uneclipsed UV continuum was detected at wavelengths shorter than 1600 A. The IUE high dispersion SWP spectrum revealed that the emission lines are extremely broad, almost symmetrical lines with weak, slightly blue shifted absorption components. No evidence of carbon is seen in the emission or absorption spectrum of V356 Sgr in eclipse. A model for the origin of the circumstellar matter in this binary system is presented. The Voyager ultraviolet observations of β Lyr show a strong far-UV continuum that is detectable down to 912 A The far-UV continuum flux level was variable on time scales shorter than the orbital period and displayed no obvious orbital modulation or eclipses. The spectral shape of the far-UV continuum closely resembles that of a UX UMa type cataclysmic variable. On 16 August 1985 an rapid brightening of the far-UV continuum was observed which was also reminiscent of cataclysmic variables. Analysis of the β Lyr data suggest that the central object must be small, with a radius on the order of 1 R⊙ or less.
Molecular dynamics simulations of droplet evaporation

The complete evaporation of a three-dimensional submicron droplet under subcritical conditions has been modeled using molecular dynamics. The two-phase system consisted of 2048 argon atoms modeled using a Lennard-Jones 12-6 potential distributed between a single droplet and its surrounding vapor. The system was first allowed to relax to equilibrium, then the droplet was evaporated by increasing the temperature of the vapor phase atoms at the boundaries of the system until only the vapor phase remained. The computed evaporation rate agrees with that predicted by the Knudsen aerosol theory.
Dehn surgeries on knots in product manifolds

We show that if a surgery on a knot in a product sutured manifold yields the same product sutured manifold, then this knot is a 0- or 1-crossing knot. The proof uses techniques from sutured manifold theory.
Is induced QCD really QCD? The preservation of asymptotic freedom by matter interactions

Abstract The program of induced QCD requires that there exist self-interactions among the heavy matter fields (an adjoint scalar and a few fermions in the fundamental representation) which tend to spoil the asymptotic freedom of SU ( N ) gauge theory. We consider general interactions between such matter fields and show that, on the contrary, to two loops, they all tend to enhance asymptotic freedom in the perturbative regime. This result casts doubt on whether induced QCD is equivalent to real QCD.
More evidence indicates link between El Niños and seismicity

In 1988, evidence showed a correlation between the five extreme lows in the Southern Oscillation Index (SOI) from 1964 through 1987 and episodic seismic activity along the East Pacific Rise (EPR) from 20°S to 40°S. This area contains one of the Earth's most rapidly spreading ridge systems (Figure 1), where large amounts of energy are released through submarine volcanism and hydrothermal activity. Now that another El Nin˜o/Southern Oscillation (ENSO) episode may have drawn to a close, it is time to examine additional seismicity and SOI values. Observed coincidences are often the basis for discovery, and reviewing the available data led us to note several. Two distinct phenomena—El Ninos and earthquake swarms—seem to occur almost simultaneously in spite of their irregular recurrence rates and durations. Also, we found that what may be the longest lasting of the past six Ninos coincides with the longest lasting and most anomalous episode of seismic activity, which occurred from 1964 through 1992 along the EPR from 15°S to 40°S.
The North Atlantic subtropical surface salinity maximum as observed by Aquarius

Aquarius satellite-derived sea surface salinity (SSS) data from August 2011 through September 2013 reveals significant seasonal migration and freshening of the subtropical surface salinity maximum (SSS-max) area in the North Atlantic, in good agreement with in situ observations, including those obtained as part of the SPURS (Salinity Processes in the Upper Ocean Regional Study) field experiment in 2012–2013. The SSS-max fluctuated in surface area—as defined by the 37.4 surface isohaline—during the course of the Aquarius time series by about 67%. The SSS-max has a surprisingly large amount of non-seasonal variability, including a general decrease in salinity throughout the eastern subtropical North Atlantic between 2011–2012 and 2012–2013 of about 0.1–0.2. The documented seasonal variability is weakest in the maximum salinity area and increases toward the north and south, respectively. This is consistent with the important role played by Ekman transport and regional excess of evaporation over precipitation in the formation of the SSS-max.
Oxidation of pyrrole α-methyl to formyl with ceric ammonium nitrate

Abstract Pyrrole α-aldehydes can be prepared in high yield by oxidation of pyrrole α-methyl groups with ceric ammonium nitrate when the pyrrole ring also has an α-carboxylic acid ester group.
Centrifugal Breakout of Magnetically Confined Line-driven Stellar Winds

We present two-dimensional MHD simulations of the radiatively driven outflow from a rotating hot star with a dipole magnetic field aligned with the star's rotation axis. We focus primarily on a model with moderately rapid rotation (half the critical value) and also a large magnetic confinement parameter, η* ≡ BR/V∞ = 600. The magnetic field channels and torques the wind outflow into an equatorial, rigidly rotating disk extending from near the Kepler corotation radius outward. Even with fine-tuning at lower magnetic confinement, none of the MHD models produce a stable Keplerian disk. Instead, material below the Kepler radius falls back onto the stellar surface, while the strong centrifugal force on material beyond the corotation escape radius stretches the magnetic loops outward, leading to the episodic breakout of mass when the field reconnects. The associated dissipation of magnetic energy heats material to temperatures of nearly 108 K, high enough to emit hard (several keV) X-rays. Such centrifugal mass ejection represents a novel mechanism for driving magnetic reconnection and seems a very promising basis for modeling X-ray flares recently observed in rotating magnetic Bp stars like σ Ori E.
The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations

We compare the predictions of three physical models for the origin of the hot halo gas with the observed halo X-ray emission, derived from 26 high-latitude XMM-Newton observations of the soft X-ray background between l = 120° and l = 240°. These observations were chosen from a much larger set of observations as they are expected to be the least contaminated by solar wind charge exchange emission. We characterize the halo emission in the XMM-Newton band with a single-temperature plasma model. We find that the observed halo temperature is fairly constant across the sky (~(1.8-2.4) × 106 K), whereas the halo emission measure varies by an order of magnitude (~0.0005-0.006 cm–6 pc). When we compare our observations with the model predictions, we find that most of the hot gas observed with XMM-Newton does not reside in isolated extraplanar supernova (SN) remnants—this model predicts emission an order of magnitude too faint. A model of an SN-driven interstellar medium, including the flow of hot gas from the disk into the halo in a galactic fountain, gives good agreement with the observed 0.4-2.0 keV surface brightness. This model overpredicts the halo X-ray temperature by a factor of ~2, but there are a several possible explanations for this discrepancy. We therefore conclude that a major (possibly dominant) contributor to the halo X-ray emission observed with XMM-Newton is a fountain of hot gas driven into the halo by disk SNe. However, we cannot rule out the possibility that the extended hot halo of accreted material predicted by disk galaxy formation models also contributes to the emission.
Dynamical upper bounds for one-dimensional quasicrystals

Abstract Following the Killip–Kiselev–Last method, we prove quantum dynamical upper bounds for discrete one-dimensional Schrodinger operators with Sturmian potentials. These bounds hold for sufficiently large coupling, almost every rotation number, and every phase.
Thermalization in multiphoton excitation of molecules

Abstract The thermalization of coherent multiphoton excitation of molecules is examined. An inspection of the level distribution of a driven anharmonic oscillator, which is subject to energy and phase dissipation to a bath, reveals that phase relaxation (dephasing) due to the bath perturbation plays a major role in the thermalization process.
A 512-kb flash EEPROM embedded in a 32-b microcontroller

A 512-kb flash EEPROM developed for microcontroller applications is reported. Many process and performance constraints associated with the conventional flash EEPROM have been eliminated through the development of a new flash EEPROM cell and new circuit techniques. Design of the 512-kb flash EEPROM, which is programmable for different array sizes, has been evaluated from 256- and 384-kb arrays embedded in new 32-b microcontrollers. The 512-kb flash EEPROM has incorporated the newly developed source-coupled split-gate (SCSG) flash EEPROM cell, Zener-diode controlled programming voltages, internally generated erase voltage, and a new differential sense amplifier. It has eliminated overerase and program disturb problems without relying on tight process controls and on critical operational sequences and timings, such as intelligent erase, intelligent program, and preprogram before erase. A modular approach was used for chip design to minimize development time and for processing technology to achieve high manufacturability and flexibility. >
Empirical prediction limit estimation methods for feed-forward neural networks

Feed-forward neural networks (FFNs) have gained a lot of interest in the last decade as empirical models for their powerful representational capacity, non-parametric nature and multivariate characteristics. While these neural network models focus primarily on accurate prediction of output values, often outperforming their statistical counterparts in dealing with sparse date sets, they usually do not provide any information regarding the confidence with which they make these predictions. Since prediction limits (PLs) indicate the extent to which one can rely on predictions for making future decisions, it is of paramount importance to estimate these limits. Two empirical PL estimation methods for FFNs are presented. The two methods differ in one fundamental aspect: the method employed for modeling the properties of the neural network model residuals. While one method uses a local approximation scheme, the other utilizes a global approximation scheme. Simulation results reveal that both methods have their re...
On the role of the second law of thermodynamics in mechanics of materials

Abstract This paper summarizes the recent work of Green and Naghdi 1,2 concerning the thermomechanics of dissipative materials. The main features are: 1. (a) the introduction of a conservation law for entropy which holds for all materials, 2. (b) the use of the energy equation as an identity for all processes, thereby leading to restrictions on constitutive equations, and 3. (c) the development of an inequality representing a mathematical interpretation of a statement of the second law of thermodynamics.
Generating the Swept Area of a Body Undergoing Planar Motion

The swept area ofa two-dimensional object undergoing motion in its plane of definition is the union of the area occupied by the object at all positions during the motion. A methodology for determining a close approximation to an exact swept area of a convex object with a known arbitrary motion is developed here. The resulting swept areas are used as constraints in the geometric design of the links in an interference-free complex planar mechanism. Criteria for determining individual points falling on the border of the swept area are derived from envelope theory. These points are determined at a reference position of the sweeping body using generalized moving centrodes. The swept area is constructed from these points plus sections of the border of the moving body at some selected positions. Overlap of the swept area onto itself, caused by the body moving back to an area which it occupied previously, is processed by dividing the overall swept area into sub swept areas which are free of overlap. An eleven-step swept area generation algorithm is presented along with an example.
Short coherence length superconductivity : A generalization of BCS theory for the underdoped cuprates

Abstract On the basis of the observed short coherence lengths in the cuprates we argue that a BCS—Bose-Einstein condensation (BEC) crossover approach is an appropriate starting point for correcting the mean field approach of BCS and, thereby, for addressing pseudogap phenomena in these materials. Our version of the BCS-BEC approach is based on a particular Green's function decoupling scheme which should be differentiated from others in the literature, and which yields (i) the Leggett crossover ground state (for all coupling constants g , at T = 0) and (ii) BCS theory (for all T ≤ T c over a range of small g ). In this paper we provide a simple physical picture of the pseudogap phase above and below T c , and review the quantitative and qualitative implications of this theory, which, for the most part have been published in a series of recent papers.
Generalized compressibility in a glass-forming liquid

Abstract We introduce a new quantity to probe the glass transition. This quantity is a linear generalized compressibility which depends solely on the positions of the particles. We have performed a molecular dynamics simulation on a glass-forming liquid consisting of a two-component mixture of soft spheres in three dimensions. As the temperature is lowered, the generalized compressibility drops sharply at the glass transition. Our results are consistent with the kinetic view of the glass transition, but not with an underlying second-order phase transition.
The outrigger: a prehistoric feedback mechanism

The history of the outrigger, an ancient Polynesian device with a feedback mechanism, is chronicled in the paper with particular focus on its basic roll stability and the outrigger loop. The action of an outrigger is two-fold. First, the outrigger adds buoyancy to the vessel since the outriggers are made of materials that float irrespective of their shapes. More importantly, the addition of a float at the end of a boom dramatically increases the roll stability of small canoes.
ON ABELIAN COSET GENERALIZED VERTEX ALGEBRAS

This paper studies the algebraic aspect of a general abelian coset theory with a work of Dong and Lepowsky as our main motivation. It is proved that the vacuum space ΩV (or the space of highest weight vectors) of a Heisenberg algebra in a general vertex operator algebra V has a natural generalized vertex algebra structure in the sense of Dong and Lepowsky and that the vacuum space ΩW of a V-module W is a natural ΩV-module. The automorphism group AutΩVΩV of the adjoint ΩV-module is studied and it is proved to be a central extension of a certain torsion free abelian group by C×. For certain subgroups A of AutΩVΩV, certain quotient algebras of ΩV are constructed. Furthermore, certain functors among the category of V-modules, the category of ΩV-modules and the category of -modules are constructed and irreducible ΩV-modules and -modules are classified in terms of irreducible V-modules. If the category of V-modules is semisimple, then it is proved that the category of -modules is semisimple.
Dynamics of facial expression extracted automatically from video

We present a systematic comparison of machine learning methods applied to the problem of fully automatic recognition of facial expressions, including AdaBoost, support vector machines, and linear discriminant analysis. Each video-frame is first scanned in real-time to detect approximately upright-frontal faces. The faces found are scaled into image patches of equal size, convolved with a bank of Gabor energy filters, and then passed to a recognition engine that codes facial expressions into 7 dimensions in real time: neutral, anger, disgust, fear, joy, sadness, surprise. We report results on a series of experiments comparing spatial frequency ranges, feature selection techniques, and recognition engines. Best results were obtained by selecting a subset of Gabor filters using AdaBoost and then training Support Vector Machines on the outputs of the filters selected by AdaBoost. The generalization performance to new subjects for a 7-way forced choice was 93% or more correct on two publicly available datasets, the best performance reported so far on these datasets. The outputs of the classifier change smoothly as a function of time and thus can be used for unobtrusive expression dynamics capture. We developed an end-to-end system that provides facial expression codes at 24 frames per second and animates a computer-generated character. In real-time this expression mirror operates down to resolutions of 16 pixels from eye to eye. We also applied the system to fully automated facial action coding.
Employment Growth from Public Support of Innovation in Small Firms

Herein, we investigate the impacts of the US publicly funded Small Business Innovation Research (SBIR) program's funding on the overall employment growth of SBIR award-recipient firms. This paper is motivated by the US Congress’ continued emphasis on employment growth during its deliberations on the reauthorization of the SBIR program. We set forth a model of employment growth; the model offers a framework through which we can compare a firm's actual level of employment after receipt of an SBIR award and completion of the research project to the level of employment predicted by the firm's characteristics prior to the award. Using data collected by the National Research Council within the National Academies, we estimate our model, and we conclude that, on average, the overall employment effects associated with the SBIR program are large absolutely and relative to dollars of funding, but these effects are, in general, not statistically significant.
Reservoir management using streamline-based flood efficiency maps and application to rate optimization ☆

Abstract 3-D streamlines provide an effective tool for reservoir management because of their ability to display reservoir flow and well connections in a physically intuitive manner. Streamlines have been extensively used to investigate the interaction between heterogeneity and well patterns and also for rate allocation and pattern balancing. More recently, streamlines have been used in conjunction with constrained optimization techniques for improving waterflood performance via rate control. Field scale rate optimization problems, however, involve highly complex reservoir models, production and facilities constraints and a large number of unknowns, making them inaccessible for routine waterflood management. In this paper we provide a simple and easy to use workflow for waterflood rate optimization using streamline-based flood efficiency maps that display the flux and time of flight distribution amongst producing wells. We demonstrate the use of flood efficiency map to optimize the injection/production rates to maximize waterflood sweep efficiency by equalizing the average time of flight (TOF) amongst the producing wells in regional basis. Our optimization approach is extremely efficient because it relies on simple analytic calculations to compute weighting factors for injection and production rates to minimize the TOF variance amongst producing wells. Because the approach does not rely on formal and complex optimization tools, it is particularly well-suited for large-scale field application. Also, the approach can be used with both streamline and finite difference simulators. For finite-difference simulations, the streamlines and time of flight are derived from the flux field generated by the simulator. Multiple examples are presented to support the robustness and efficiency of the proposed waterflood management scheme. These include 2D synthetic examples for validation and a 3D field application.
Two unfortunate properties of pure f-vectors

The set of f-vectors of pure simplicial complexes is an important but little understood object in combinatorics and combinatorial commutative algebra. Unfortunately, its explicit characterization appears to be a virtually intractable problem, and its structure very irregular and complicated. The purpose of this note, where we combine a few different algebraic and combinatorial techniques, is to lend some further evidence to this fact. We first show that pure (in fact, Cohen-Macaulay) f-vectors can be nonunimodal with arbitrarily many peaks, thus improving the corresponding results known for level Hilbert functions and pure O-sequences. We provide both an algebraic and a combinatorial argument for this result. Then, answering negatively a question of the second author and collaborators posed in the recent AMS Memoir on pure O-sequences, we show that the Interval Property fails for the set of pure f-vectors, even in dimension 2.
Transition-state analogue inhibitors of chorismate mutase

Abstract The synthesis of seven bi- and tricyclic chorismate analogues 9 - 15 and their biological evaluation as mutase inhibitors is described. A tandem Cope rearrangement/Diels-Alder cycloaddition strategy was employed to prepare tricyclo[3.3.1.02,7]non-3-enes functionalized with carboxylic and/or phosphonic acid groups.
Local Solution and Extension to the Calabi Flow

We consider the local solution of the Calabi flow for rough initial data. In particular, we prove that for any smooth metric, there is a Cα neighborhood such that the Calabi flow has a short time solution for any Cα metric in the neighborhood. We also prove that on a compact Kahler surface, if the evolving metrics of the Calabi flow are all L∞ equivalent, then the Calabi flow exists for all time and converges to an extremal metric subsequently.
Gallium(III) chloride-catalyzed double insertion of isocyanides into epoxides.

Gallium(III) chloride-catalyzed double insertion of aryl isocyanides into terminal and disubstituted epoxides leads to α,β-unsaturated α-amino iminolactones (3-amino-2-iminio-2,5-dihydrofurans).
γ-substituent effects on the oxidative cyclization of o-acyl β,γ-unsaturated hydroxamates

Abstract Bromine induced cyclization of O-acyl β,γ-unsaturated hydroxamates to β-lactams is compatible with a variety of γ-substitutents.
Phase transition of a Bose gas in a harmonic potential

We consider a Bose gas confined by a harmonic potential. We define an appropriate thermodynamic limit and analyze the properties of the phases and phase transition in this limit. Critical properties in the presence of the potential are found to be different from, though simply related to, those in the usual translationally invariant case. We argue that the properties of magnetically trapped rubidium and sodium gases (in which Bose-Einstein condensation has recently been observed) are well approximated by our thermodynamic limit except in a narrow window of temperature around the critical temperature. We also consider the effect of the confining potential on the non-equilibrium dynamics following a rapid quench to the ordered side and give a scaling description of the late-time universal dynamics.
Effects of Catalyst Activation and Ligand Steric Properties on the Enantioselective Allylation of Amines and Phenoxides

The yields, enantioselectivities, and regioselectivities of the reactions of amines and phenoxides with allylic carbonates in the presence of a metallacyclic iridium catalyst were compared. These data show that both preactivation of the catalyst and the size of the ligand affect the yield, enantioselectivity, and regioselectivity. With the activated catalyst containing a bis-naphthethylamino group, the allylic amination and etherification of a broad range of allylic carbonates occurred in high yields and with high regioselectivities and enantioselectivities.
Using galaxy cluster peculiar velocities to constrain cosmological parameters

Abstract Galaxy cluster peculiar velocities can be inferred from high—sensitivity, high—resolution multiple-frequency observations in the 30 to 400 GHz range. While galaxy cluster counts and power spectra are sensitive to the growth factor, peculiar velocities are sensitive to the time—derivative of the growth factor and are hence complementary. Using linear perturbation theory, we forecast constraints on ωm, H0 and the dark—energy equation of state parameter, w, given 820 densely sampled cluster locations (at z ≅ 1) from a ΛCDM N-body simulation and 820 sparsely sampled cluster locations in a broader redshift range.
Palladium-Catalyzed Asymmetric Ring Expansion of Allenylcyclobutanols: An Asymmetric Wagner−Meerwein Shift

In this study, we developed a palladium-catalyzed atom economic asymmetric Wagner−Meerwein shift of allenylcyclobutanol substrates. It is an excellent method for creating functionalized cyclopentanones with an α-chiral O-tertiary center by ring expansion of allenylcyclobutanols. This reaction was initiated by hydropalladation and afforded excellent enantioselectivity as well as atom economy. This method provides an efficient route toward the synthesis of natural products such as trans-kumausyne's family, spiro ring systems. In addition, we obtained excellent diastereoselectivity and enantioselectivity at the same time by using 3-monosubstituted allenylcyclobutanol.
Robust eigenstructure assignment for the extended medium range air-to-air missile

Abstract A new sufficient condition for the robust stability of a linear time invariant system subject to linear time varying structured state space uncertainty is presented. This sufficient condition is a sum of terms each of which involves the ith right eigenvector, the ith left eigenvector, and the real part of the ith eigenvalue. This new robustness result is less conservative than an earlier result which involves the modal matrix and the real part of the eigenvalue which is closest to the imaginary axis in the complex plane. A robust design is computed for the Extended Medium Range Air-to-Air Missile and the new design is compared with an earlier orthogonal projection eigenstructure assignment design. The new design method uses the MATLABTM Optimization Toolbox to minimize the integral of the deviations of the integrated roll rate (which is approximately the bank angle) from zero. The integral is approximated by a sum of discrete samples of the integrated roll rate while normalizing the integration width to unity. Constraints are placed on the real part of the Dutch roll and roll mode eigenvalues, the damping ratios of the Dutch roll and roll mode, the aileron and rudder deflection rates, and the sufficient condition for robust stability. The new design satisfies the robustness condition while also yielding an improved transient response.
An adaptive M-estimation framework for robust image super resolution without regularization

This paper introduces a new image super-resolution algorithm in an adaptive, robust M-estimation framework. Super-resolution reconstruction is formulated as an optimization (minimization) problem whose objective function is based on a robust error norm. The effectiveness of the proposed scheme lies in the selection of a specific class of robust M-estimators, redescending M-estimators , and the incorporation of a similarity measure to adapt the estimation process to each of the low-resolution frames. Such a choice helps in dealing with violations to the assumed imaging model that could have generated the low-resolution frames from the unknown high-resolution one. The proposed approach effectively suppresses the outliers without the use of regularization in the objective function, and results in high-resolution images with crisp details and no artifacts. Experiments on both synthetic and real sequences demonstrate the superior performance over methods based on the L 2 and L 1 in the objective function.
More Choice, Less Crime

Abstract Previous research debates whether public school choice improves students' academic outcomes, but there is little examination of its effects on their nonacademic outcomes. We use data from a nationally representative sample of high school students, a previously developed Tiebout choice measure, and metropolitan-level data on teenage arrest rates to examine how public school choice affects students' propensity to be arrested or to join a gang. Adolescents in metropolitan areas with more public school choice are less likely to be associated with criminal activity, suggesting that the benefits of public school choice extend outside the classroom.
Synthesis of substituted 3-hydroxy-4-alkoxycarbonyl-2-azetidinones

Abstract A short chemical process is described for the synthesis of optically active 3-hydroxy-4-alkoxycarbonyl-2-azetidinones (β-lactams) from L-tartaric acid.
The Mid-Infrared Color-Luminosity Relation and the Local 12 Micron Luminosity Function

We have established a model to systematically estimate the contribution of the mid-IR emission features between 3 and 11.6 μm to the IRAS in-band fluxes, using the results of Infrared Space Observatory PHT Spectrophotometer observation of 16 galaxies by Lu et al. in 1997. The model is used to estimate more properly the k-corrections for calculating the rest frame 12 and 25 μm fluxes and luminosities of IRAS galaxies. We have studied the 12-25 μm color-luminosity relation for a sample of galaxies selected at 25 μm. The color is found to correlate well with the 25 μm luminosity, the mid-IR luminosity, and the ratio of far-infrared and blue luminosities. The relations with the mid-IR luminosities are more sensitive to different populations of galaxies, while a single relation of the 12-25 μm color versus the ratio of the far-infrared and blue luminosities applies equally well to these different populations. The luminous and ultraluminous infrared galaxies have redder 12-25 μm colors than those of the quasars. These relations provide powerful tools to differentiate different populations of galaxies. The local luminosity function at 12 μm provides the basis for interpreting the results of deep mid-IR surveys planned or in progress with Infrared Space Observatory, Wide-Field Infrared Explorer, and Space Infrared Telescope Facility. We have selected a sample of 668 galaxies from the IRAS Faint Source Survey flux density limited at 200 mJy at 12 μm. A 12 μm local luminosity function is derived and, for the first time in the literature, effects of density variation in the local universe are considered and corrected in the calculation of the 12 μm luminosity function. It is also found that the 12 μm selected sample is dominated by quasars and active galaxies, which therefore strongly affect the 12 μm luminosity function at high luminosities. The ultraluminous infrared galaxies are relatively rare at 12 μm compared to a 25 μm sample.
Shuttle demonstration of large space structure fabrication and assembly

Abstract The purpose of this paper is to describe a program aimed at an early on orbit demonstration of a large space structure fabrication and assembly capability. Requirements for the demonstration concept have been formulated. The concept that has been selected to meet these requirements is a Large Space Structure Platform consisting of a triangular prism of 31.5 m length. Sensors can be mounted on this platform to perform Earth observation measurements from space. Structural elements of the platform are fabricated using an automated beam builder in the Shuttle Orbiter payload bay. Special fixtures are designed to assemble the structure with the aid of the Remote Manipulator System and two astroworkers in an EVA mode. Results are shown of the platform preliminary design in terms of a design layout with related structural, thermal, mass properties and control dynamics data. The assembly scenario is described. Estimates of the total construction time and Orbiter support requirements are also presented.
Learning-induced autonomy of sensorimotor systems

The authors used new network-analysis algorithms to examine how distributed networks of brain areas are reorganized as humans learn a new motor skill. Using fMRI, the authors found that learning induced autonomy of sensorimotor systems and that a release of cognitive control hubs predicted individual differences in learning.
Dynamics of a Massive Black Hole at the Center of a Dense Stellar System

We develop a simple physical model to describe the dynamics of a massive pointlike object, such as a black hole, near the center of a dense stellar system. It is shown that the total force on this body can be separated into two independent parts, one of which is the slowly varying influence of the aggregate stellar system, and the other being the rapidly fluctuating stochastic force due to discrete encounters with individual stars. For the particular example of a stellar system distributed according to a Plummer model, it is shown that the motion of the black hole is then similar to that of a Brownian particle in a harmonic potential, and we analyze its dynamics using an approach akin to Langevin's solution of the Brownian motion problem. The equations are solved to obtain the average values, time autocorrelation functions, and probability distributions of the black hole's position and velocity. By comparing these results with N-body simulations, we demonstrate that this model provides a very good statistical description of the actual black hole dynamics. As an application of our model, we use our results to derive a lower limit on the mass of the black hole Sgr A* in the Galactic center.
Improved Parallel Algorithms for Spanners and Hopsets

We use exponential start time clustering to design faster parallel graph algorithms involving distances. Previous algorithms usually rely on graph decomposition routines with strict restrictions on the diameters of the decomposed pieces. We weaken these bounds in favor of stronger local probabilistic guarantees. This allows more direct analyses of the overall process, giving: Linear work parallel algorithms that construct spanners with O(k) stretch and size O(n1+1/k) in unweighted graphs, and size O(n1+1/k log k) in weighted graphs.Hopsets that lead to the first parallel algorithm for approximating shortest paths in undirected graphs with O(m poly log n) work.
A Multimedia Application for Teaching Design for Manufacturing

This paper describes the interactive multimedia injection molding tutor developed at the University of Massachusetts Amherst. The purpose of the tutor is to use visually stimulating animations in order to enable the user, a student or anyone not familiar with the process of injection molding, in understanding the relationship between part design and the ease or difficulty of producing the part. Preliminary evaluations indicate that the tutor can be successful in achieving these objectives.
Finite element/finite volume approaches with adaptive time stepping strategies for transient thermal problems

Transient thermal analysis of engineering materials and structures by space discretization techniques such as the finite element method (FEM) or finite volume method (FVM) lead to a system of parabolic ordinary differential equations in time. These semidiscrete equations are traditionally solved using the generalized trapezoidal family of time integration algorithms which uses a constant single time step. This single time step is normally selected based on the stability and accuracy criteria of the time integration method employed. For long duration transient analysis and/or when severe time step restrictions as in nonlinear problems prohibit the use of taking a larger time step, a single time stepping strategy for the thermal analysis may not be optimal during the entire temporal analysis. As a consequence, an adaptive time stepping strategy which computes the time step based on the local truncation error with a good global error control may be used to obtain optimal time steps for use during the entire analysis. Such an adaptive time stepping approach is described here. Also proposed is an approach for employing combinedFEM/FVM mesh partitionings to achieve numerically improved physical representations. Adaptive time stepping is employed thoughout to practical linear/nonlinear transient engineering problems for studying their effectiveness in finite element and finite volume thermal analysis simulations.
NEW MASSIVE BINARIES IN THE CYGNUS OB2 ASSOCIATION

As part of an ongoing study to determine the distribution of orbital parameters for massive binaries in the Cyg OB2 association, we present the orbital solutions for two new single-lined spectroscopic binaries, MT 059 (O8 V) and MT 258 (O8 V), and one double-lined eclipsing binary (Schulte 3). We also constrain the orbital elements of three additional double-lined systems (MT 252, MT 720, and MT 771). Periods for all systems range from 1.5 to 19 days, and eccentricities range from 0 to 0.11. The six new OB binary systems bring the total number of multiple systems within the core region of Cyg OB2 to 11. The current sample does not show evidence for a "twin-heavy" binary distribution.
A Conceptual Definition and Theoretical Model of Public Deliberation in Small Face—to—Face Groups

Although scholars have begun to study face—to—face deliberation on public issues, “deliberation” has no clear conceptual definition and only weak moorings in larger theories. To address these problems, this essay integrates diverse philosophical and empirical works to define deliberation and place it in a broader theoretical context. Public deliberation is a combination of careful problem analysis and an egalitarian process in which participants have adequate speaking opportunities and engage in attentive listening or dialogue that bridges divergent ways of speaking and knowing. Placed in the meta—theoretical framework of structuration theory (Giddens, 1984), deliberation is theorized to exist at the center of a homeostatic loop, in which deliberative practice reinforces itself. A review of theory and research on the causes and effects of deliberation leads us to develop this structurational conceptualization into the self—reinforcing model of deliberation. This model posits that public deliberation is more likely to occur when discussion participants perceive potential common ground, believe deliberation is an appropriate mode of talk, possess requisite analytic and communication skills, and have sufficient motivation. Deliberation directly reinforces participants' deliberative habits and skills, and it indirectly promotes common ground and motivation by broadening participants' public identities and heightening their sense of political efficacy.
Supramolecular chemistry and self-assembly

Supramolecular systems—their successes, problems, and potential—are discussed with allusion to specific examples.
Further studies on carbon-carbon bond formation based on the radical reactions of acyl derivatives of N-hydroxy-2-thiopyridone

Abstract By careful exclusion of oxygen, carbon radicals, generated from the W lamp photolysis of O -acyl derivatives of N -hydroxy-2-thiopyridone, can be added efficiently to methylvinyl ketone. Extension to the radical from pent-4-enoic acid provides another synthesis of cyclopentane derivatives. Analogous additions with other electrophilic olefins are also reported.
Synthesis of bifluorenes via cobalt halide radical coupling

Abstract Reaction of in situ generated lithium fluorenide salts with cobalt chloride results in formation of the corresponding bifluorenes. The scope of fluorenes that can be coupled include those containing substituents amenable to polymerization for application to poly(bifluorene) synthesis and alkyl substituted fluorenes for use in the preparation of bimetallic transition metal complexes. Based on experiments using a radical trap, the reaction mechanism involves reduction of cobalt and subsequent fluorenyl radical coupling. Overall, this study demonstrates a simple and effective method for preparation of hindered tertiary and quaternary C–C bonds using a readily available and inexpensive coupling agent.