cssi/SciSciGPT-SciSciNet huggingface dataset:
Variation in the scattering shroud surrounding markarian 231

We present a detailed study of the nuclear structure of the highly polarized broad absorption line quasar, Mrk 231, through a multiwavelength campaign of Chandra observations, optical spectroscopy, optical spectropolarimetry, and imaging polarimetry. This campaign was designed to extend the 40 ks Chandra study of Gallagher and coworkers and the optical and UV spectropolarimetric study of Smith and coworkers to probe variability on multiple timescales. As direct emission from the nucleus is heavily obscured at optical through X-ray wavelengths, the detailed study of scattered emission has lead to insights into the stratified and complex central region of this active galaxy. Although significant continuum variability is not detected in any of the three new 40 ks Chandra observations, we investigate Fe K? emission features in the individual and combined spectra. Comparing echelle spectra of the Na I D absorption lines with the literature, we show that one system disappeared in 2000 only to reappear in later epochs. Notably, we detect a large decrease in polarization across the entire optical spectrum of Mrk 231 from 1995 to 2003. Although the polarization fraction fell, e.g., from 4% to 3% at ?obs ~ 6000 ?, the polarization position angle spectrum remained unchanged. The optical polarization behavior is consistent with a decrease in the flux scattered by circumnuclear material on spatial scales where the broad-line region is resolved by the scattering material. Ultraviolet imaging polarimetry of Mrk 231 by the Hubble Space Telescope sets an upper limit on the distance between the active nucleus and the scattering regions of <20 pc.
Lower bounds for the cycle detection problem

Abstract Given a function f over a domain and an element x in the domain, the cycle detection problem is to find a repetition in the sequence of values x , f(x), f(f(x)), f 3 (x) ,…, if one exists. This paper investigates lower bounds on the number of function evaluations needed when there is a bound on the amount of memory available. For certain restricted classes of algorithms which use two memory locations optimality is achieved. A summary of the major results appears in the final section.
On the existence of extremal cones and comparative probability orderings

Abstract We study the recently discovered phenomenon [Conder, M. D. E., & Slinko, A. M. (2004). A counterexample to Fishburn's conjecture. Journal of Mathematical Psychology, 48(6), 425–431] of existence of comparative probability orderings on finite sets that violate the Fishburn hypothesis [Fishburn, P. C. (1996). Finite linear qualitative probability. Journal of Mathematical Psychology, 40, 64–77; Fishburn, P. C. (1997). Failure of cancellation conditions for additive linear orders. Journal of Combinatorial Designs, 5, 353–365]—we call such orderings and the discrete cones associated with them extremal. Conder and Slinko constructed an extremal discrete cone on a set of n = 7 elements and showed that no extremal cones exist on a set of n ⩽ 6 elements. In this paper we construct an extremal cone on a finite set of prime cardinality p if p satisfies a certain number theoretical condition. This condition has been computationally checked to hold for 1725 of the 1842 primes between 132 and 16,000, hence for all these primes extremal cones exist.
Are entangled particles connected by wormholes? Evidence for the ER=EPR conjecture from entropy inequalities

If spacetime is built out of quantum bits, does the shape of space depend on how the bits are entangled? The $\mathrm{ER}=\mathrm{EPR}$ conjecture relates the entanglement entropy of a collection of black holes to the cross sectional area of Einstein-Rosen (ER) bridges (or wormholes) connecting them. We show that the geometrical entropy of classical ER bridges satisfies the subadditivity, triangle, strong subadditivity, and Cadney-Linden-Winter inequalities. These are nontrivial properties of entanglement entropy, so this is evidence for $\mathrm{ER}=\mathrm{EPR}$. We further show that the entanglement entropy associated with classical ER bridges has nonpositive tripartite information. This is not a property of entanglement entropy, in general. For example, the entangled four qubit pure state $|GH{Z}_{4}⟩=(|0000⟩+|1111⟩)/\sqrt{2}$ has positive tripartite information, so this state cannot be described by a classical ER bridge. Large black holes with massive amounts of entanglement between them can fail to have a classical ER bridge if they are built out of $|GH{Z}_{4}⟩$ states. States with nonpositive tripartite information are called monogamous. We conclude that classical ER bridges require monogamous EPR correlations.
Modeling Pulsar Wind Nebulae

Abstract In the last few years, new observations by CHANDRA and XMM have shown that Pulsar Wind Nebulae present complex but similar inner features, with the presence of axisymmetric rings and jets, which are generally referred to as a jet-torus structure. Due to the rapid growth in accuracy and robustness of numerical schemes for relativistic fluid-dynamics, it is now possible to model the flow and magnetic structure of the relativistic plasma responsible for the emission. Recent results have clarified how the jet and rings are formed, suggesting that the morphology is strongly related to the wind properties, so that, in principle, it is possible to infer the conditions in the unshocked wind from the nebular emission. I will review here the current status in the modeling of Pulsar Wind Nebulae, and, in particular, how numerical simulations have increased our understanding of the flow structure, observed emission, polarization and spectral properties. I will also point to possible future developments of the present models.
Progression of performance assessment modeling for the Yucca Mountain disposal system for spent nuclear fuel and high-level radioactive waste

Abstract This paper summarizes the evolution of consequence modeling for a repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain in southern Nevada. The discussion includes four early performance assessments (PAs) conducted between 1982 and 1995 to support selection and to evaluate feasibility and three major PAs conducted between 1998 and 2008 to evaluate viability, recommend the site, and assess compliance. Modeling efforts in 1982 estimated dose to individuals 18 km from the site caused by volcanic eruption through the repository. Modeling in 1984 estimated releases via the groundwater pathway because of container corrosion. In combination, this early analysis supported the first environmental assessment. Analysts in 1991 evaluated cumulative release, as specified in the 1985 US radiation protection standards, via the groundwater pathway over 104 yr at a 5-km boundary by modeling waste degradation and flow/transport in the saturated and unsaturated zones. By 1992, however, the US Congress mandated a change to a dose measure. Thus, the 1993 and 1995 performance assessments improved modeling of waste container degradation to provide better estimates of radionuclide release rates out to 106 yr. The 1998 viability assessment was a major step in modeling complexity. Dose at a 20-km boundary from the repository was evaluated through 106 yr for undisturbed conditions using more elaborate modeling of flow and the addition of modules for modeling infiltration, drift seepage, the chemical environment, and biosphere transport. The 2000 assessment for the site recommendation refined the analysis. Seepage modeling was greatly improved and waste form degradation modeling included more chemical dependence. The 2008 compliance assessment for the license application incorporated the influence of the seismicity on waste package performance to evaluate dose at an ~18-km boundary.
Evolution of Migrating Planets Undergoing Gas Accretion

We analyze the orbital and mass evolution of planets that undergo runaway gas accretion by means of two- and three-dimensional hydrodynamic simulations. The disk torque distribution per unit disk mass as a function of radius provides an important diagnostic for the nature of the disk-planet interactions. We present results of simulations for mass-gaining, migrating planets. For planets with an initial mass of 5 M⊕, which are embedded in disks with standard parameters and which undergo runaway gas accretion to 1 MJ, the torque distributions per unit disk mass are largely unaffected by migration and accretion for a given planet mass. The migration rates for these planets are in agreement with the predictions of the standard theory for planet migration (type I and type II migration). The planet mass growth occurs through gas capture within the planet's Bondi radius at lower planet masses, the Hill radius at intermediate planet masses, and through reduced accretion at higher planet masses due to gap formation. During runaway mass growth, a planet migrates inward by only about 20% in radius before achieving a mass of ~1 MJ. For the above models, we find no evidence of fast migration driven by coorbital torques, known as type III migration. We do find evidence of type III migration for a fixed-mass planet of Saturn's mass that is immersed in a cold and massive disk. In this case the planet migration is assumed to begin before gap formation completes. The migration is understood through a model in which the torque is due to an asymmetry in density between trapped gas on the leading side of the planet and ambient gas on the trailing side of the planet.
Decentralized dynamic processes for finding equilibrium

Abstract This paper describes a class of decentralized dynamic processes designed to converge to equilibrium when the equilibrium equations are linear. These processes can also be viewed as distributed algorithms for solving systems of linear equations, or as learning algorithms. The class includes processes that use a message space larger by one binary digit than the space in which the equilibrium exists. However, memory and time requirements increase exponentially with the number of agents (equations).
Non-metallocatalyzed epoxidation of chiral unsaturated lactams by tertiary amine N-oxides

Abstract Tertiary amine N-oxides were used to stereospecifically epoxidize chiral unsaturated bicyclic lactams in high yields (90–99%) at room temperature. This appears to be the first reported example of tertiary amine N-oxides acting as epoxidizing agents in the absence of a metal catalyst.
Determination of the charge on carbon in a bridging methylene iron dimer with solid-state deuterium NMR spectroscopy

The chemistry of bridging methylene metal dimers and the value of the /sup 13/C NMR chemical shifts have been interpreted as due to a partial negative charge on the carbon atom. PES yields a C/sub 1s/ binding energy indicative of -0.5 e charge. However, for (..mu..-CH/sub 2/)(MnCp(CO)/sub 2/)/sub 2/, a high-resolution x-ray diffraction electron density map shows no excess charge buildup. The authors are attempting to resolve the dilemma by using solid-state deuterium NMR techniques. In the results for cis-(..mu..-C/sup 2/H/sub 2/)(..sigma..-CO)(FeCp/sup d/(CO))/sub 2/ (Cp/sup d/ and 5% deuteriated cyclopentadienyl) presented here, the authors find no evidence for an excess negative charge on the bridging methylene carbon atom.
Sortable elements and Cambrian lattices

We show that the Coxeter-sortable elements in a finite Coxeter group W are the minimal congruence-class representatives of a lattice congruence of the weak order on W. We identify this congruence as the Cambrian congruence on W, so that the Cambrian lattice is the weak order on Coxeter-sortable elements. These results exhibit W-Catalan combinatorics arising in the context of the lattice theory of the weak order on W.
A Relaxation Solution for Transonic Flow over Jet Flapped Airfoils

Transonic small disturbance theory has been used as a framework for the development of a relaxation solution for the flow over supercritical jet flapped airfoils. The flexibility in grid refinement provided by the results obtained in this work for the far-field and asymptotic jet development affords an accurate, rapidly convergent algorithm for this problem. The use of a three grid approach and spatially variable relaxation provides a decisive enhancement in computational efficiency of the method. The structure of the far-field solution corresponds to a "vorticity packet" as the dominant term in the development. Results of the calculations for NACA 0012 and modified 64A406 airfoils indicate that the jet expands the region of supercritical flow and substantially enhances the lift. Comparisons with data of Yoshihara for a rearward cambered airfoil validates these conclusions.
General determination of phases in leptonic mass matrices

Abstract We construct new invariants and give several theorems which determine in general (i) the number of physically meaningful phases in charged lepton and neutrino mass matrices and (ii) which elements of these matrices can be rendered real by rephasings. We illustrate our results with simple models.
Testing Distance Estimators with the Fundamental Manifold

We demonstrate how the Fundamental Manifold (FM) can be used to cross-calibrate distance estimators even when those standard candles are not found in the same galaxy. Such an approach greatly increases the number of distance measurements that can be utilized to check for systematic distance errors and the types of estimators that can be compared. Here we compare distances obtained using Type Ia supernova (SN Ia), Cepheids, surface brightness fluctuations, the luminosity of the tip of the red giant branch, circumnuclear masers, eclipsing binaries, RR Lyrae stars, and the planetary nebulae luminosity functions. We find no significant discrepancies (differences are <2σ) between distance methods, although differences at the ~10% level cannot yet be ruled out. The potential exists for significant refinement because the data used here are heterogeneous B-band magnitudes that will soon be supplanted by homogeneous, near-infrared magnitudes. We illustrate the use of FM distances to (1) revisit the question of the metallicity sensitivity of various estimators, confirming the dependence of SN Ia distances on host galaxy metallicity, and (2) provide an alternative calibration of H 0 that replaces the classical ladder approach in the use of extragalactic distance estimators with one that utilizes data over a wide range of distances simultaneously.
Improved Inference for Respondent-Driven Sampling Data With Application to HIV Prevalence Estimation

Respondent-driven sampling is a form of link-tracing network sampling, which is widely used to study hard-to-reach populations, often to estimate population proportions. Previous treatments of this process have used a with-replacement approximation, which we show induces bias in estimates for large sample fractions and differential network connectedness by characteristic of interest. We present a treatment of respondent-driven sampling as a successive sampling process. Unlike existing representations, our approach respects the essential without-replacement feature of the process, while converging to an existing with-replacement representation for small sample fractions, and to the sample mean for a full-population sample. We present a successive-sampling based estimator for population means based on respondent-driven sampling data, and demonstrate its superior performance when the size of the hidden population is known. We present sensitivity analyses for unknown population sizes. In addition, we note tha...
High yield fusion in a staged Z-pinch

We simulate fusion in a Z-pinch, where the load is a xenon-plasma liner imploding onto a deuterium-tritium (DT) plasma target and the driver is a 2 MJ, 17 MA, 95 ns risetime pulser. The implosion system is modeled using the dynamic, 21/2D, radiation-magnetohydrodynamic code, MACH2. During implosion a shock forms in the Xe liner, transporting current and energy redially inward. After collision with the DT, a secondary shock forms pre-heating the DT to several hundred electronvolts. Adiabatic compression leads subsequently to a fusion burn, as the target is surrounded by a flux-compressed, intense, azimuthal-magnetic field. The intense-magnetic field confines fusion alpha-particles, providing an additional source of ion heating that leads to target ignition. The target remains stable up to the time of ignition. Predictions are for a neutron yield of 3.0 x 10(19) and a thermonuclear energy of 84 MJ, that is, 42 times greater than the initial, capacitor-stored energy.
SPICE model of AlGaN/GaN HEMTs and simulation of VCO and power amplifier

SPICE model parameters are extracted from reported experimental data. The model is implemented in the Cadence Affirma Analog Circuit Design Environment and Spectre simulator is used to simulate class-E power amplifier and ring voltage controlled oscillator (VCO) circuits. The availability of the SPICE model for GaN HEMTs ensures optimization of analog/RF circuits before an expensive cut-and-try method is employed.
An experimental program for the selection of "disjunctive hypotheses"

An algorithm for finding the characterization of a class of objects on the basis of a randomly ordered sequence of labeled individual objects - some members of the class, some not - is described. The class is characterized as a. disjunction of terms, each term being a conjunction of attributes. "All red, round objects or all square, small objects" is an example. Mechanisms based on this algorithm are described in terms of such properties as the amount of storage available for recording instances and the number of instances which had to be examined until the class was first guessed.
Summary Statistics of Size: Fixed Processing Capacity for Multiple Ensembles but Unlimited Processing Capacity for Single Ensembles

We assessed the processing capacity of establishing statistical summary representations (SSRs) of mean size in visual displays using the simultaneous-sequential method. Four clusters of stimuli, each composed of several circles with various diameters, were presented around fixation. Observers searched for the cluster with the largest or smallest mean size. In the simultaneous condition, all four clusters were presented concurrently; in the sequential condition, the clusters appeared two at a time. We found that the processing capacity of SSRs for multiple ensembles was as extreme as a fixed-rate bottleneck process (Experiment 1). A control experiment confirmed that this was not caused by having to compare the results of multiple averaging processes (Experiment 2). In contrast to computing SSRs across ensembles, computing SSRs for a single ensemble using the same stimuli was consistent with unlimited-capacity processing (Experiment 3). Contrary to existing claims, summary representations appear to be extracted independently for items within single ensembles but not multiple ensembles. A developing understanding of capacity limitations in perceptual processing is discussed.
A Bridgehead Enone Approach to Huperzine a

Abstract The preparation of a bicyclic amino ketone for the synthesis of huperzine has been achieved in only six steps. The key step is the introduction of the primary amine moiety via a bridgehead enone.
Stochastic selfish routing

We present a model for routing games in which edge delay functions are uncertain and users are risk-averse. We investigate how the uncertainty and risk-aversion transform the classical theory on routing games, including equilibria existence, characterization and price of anarchy.
Synthesis of (2S,3S,8S,9S)-Adda from D-glucose

Abstract The N-trifluoroacetyl derivative of the novel β-amino acid (2S,3S,8S,9S)-Adda methyl ester 4 has been prepared from the D-glucose derived oxazoline 7. A key step in the construction of 4 was the generation of the E , E decadienoate system via dissolving metal reduction of vicinal bis -mesylate 15.
ON DENOMINATORS OF THE KONTSEVICH INTEGRAL AND THE UNIVERSAL PERTURBATIVE INVARIANT OF 3-MANIFOLDS

The integrality of the Kontsevich integral and perturbative invariants is discussed. It is shown that the denominator of the degree n part of the Kontsevich integral of any knot or link is a divisor of (2!3!…n!)4(n+1)!. We prove this by establishing the existence of a Drinfeld's associator in the space of chord diagrams with special denominators. We also show that the denominator of the degree n part of the universal perturbative invariant of homology 3-spheres is not divisible by any prime greater than 2n+1.
Microwave structural determination of 2,3-diazabicyclo[2.2.1]hept-2-ene

Abstract The extremely dense microwave spectrum of 2,3-diazabicyclo[2.2.1]hept-2-ene (DBH) was studied in the region of 18–40 GHz using both Stark and radio frequency modulation. The spectra of ten isotopic species were assigned. The data obtained allowed the determination of the complete molecular structure of the molecule. Pertinent structural parameters are C 1 —N 2 = 1.50 ± 0.02 A, N 2 —N 3 = 1.246 ± 0.004 A, C 1 —C 6 = 1.54 ± 0.02 A, C 5 —C 6 = 1.552 ± 0.003 A, C 1 —C 7 = 1.534 ± 0.003 A, ∠C 1 —C 7 —C 4 = 91.3 ± 0.2°, α = 108.9 ± 0.8°, β = 128 ± 2°, γ = 123 ± 2°. The structure determined here differs significantly in some respects from a previous electron diffraction study. The dipole moment was measured by observation and analysis of the second order Stark effect of four transitions. The two non-zero dipole moment components areμ a = 2.76 ± 0.01 D, μ c = 2.1 ± 0.1 D which yield a total molecular dipole moment of 3.48 ± 0.05 D. A qualitative estimate of the lowest vibrational frequency of the molecule was obtained from relative intensity measurements. The lowest vibrational frequency is believed to be a ring distortion mode and it occurs at 246 ± 30 cm −1 .
Airway dilation in bronchiolitis obliterans after allogeneic hematopoietic stem cell transplantation.

Summary Rationale Bronchiolitis obliterans syndrome (BOS) is a late, non-infectious pulmonary complication following hematopoietic stem cell transplantation (HSCT). There is minimal data published on quantitative radiologic characterization of airway remodeling in these subjects. Objectives To examine quantitative measurements of airway morphology and their correlation with lung function in a cohort of patients who underwent HSCT and developed BOS. Methods All adult patients who underwent allogeneic HSCT at the Dana-Farber Cancer Institute/Brigham and Women's Hospital ( n = 1854) between January 1st 2000 and June 30th 2010 were screened for the development of BOS. Clinically acquired high resolution CT (HRCT) scans of the chest were collected. For each subjects discrete measures of airway wall area were performed and the square root of wall area of a 10-mm luminal perimeter (Pi10) was calculated. Measurements and main results We identified 88 cases of BOS, and 37 of these patients had available HRCT. On CT scans obtained after BOS diagnosis, the Pi10 decreased (consistent with airway dilation) as compared with pre-BOS values ( p 1 % predicted ( r = 0.636, p r = −0.736, p p Conclusions On HRCT scan BOS is characterized by central airway dilation, the degree of which is correlated to decrements in lung function. This is opposite of what has been previously demonstrated in COPD and asthma that quantitative measure of proximal airway wall thickening directly correlate with pulmonary function. Our data suggests that the pathologic process affecting the central airways is different from the pathology observed in the distal airways. Further work is needed to determine if such change can be used as a sensitive and specific tool for the future diagnosis and staging of BOS.
Construction of modular branching functions from Bethe's equations in the 3-state Potts chain

We use the single-particle excitation energies and the completeness rules of the 3-state antiferromagnetic Potts chain, which have been obtained from Bethe's equation, to compute the modular invariant partition function. This provides a fermionic construction for the branching functions of theD 4 representation ofZ 4 parafermions which complements the bosonic constructions. It is found that there are oscillations in some of the correlations and a new connection with the field theory of the Lee-Yang edge is presented.
Enhancing Attribute-Based Encryption with Attribute Hierarchy

Attribute-based encryption (ABE) has been envisioned as a promising cryptographic primitive for realizing secure and flexible access control. However, ABE is being criticized for its high scheme overhead as extensive pairing operations are usually required. In this paper, we focus on improving the efficiency of ABE by leveraging a previously overlooked fact, i.e., the often-found hierarchical relationships among the attributes that are inherent to many access control scenarios. As the first research effort along this direction, we coin the notion of hierarchical ABE (HABE), which can be viewed as the generalization of traditional ABE in the sense that both definitions are equal when all attributes are independent. We further give a concrete HABE construction considering a tree hierarchy among the attributes, which is provably secure. More importantly, our construction exhibits significant improvements over the traditional ABE when attribute hierarchies exist.
Efficient Non-Contractible Investments in Large Economies☆

Abstract Do investors making complementary investments face the correct incentives, especially when they cannot contract with each other prior to their decisions? We present a two-sided matching model in which buyers and sellers make investments prior to matching. Once matched, buyer and seller bargain over the price, taking into account outside options. Efficient decisions can always be sustained in equilibrium. We characterize the inefficiencies that can arise in equilibrium and show that equilibria will be constrained efficient. We also show that the degree of diversity in a large market has implications for the extent of any inefficiency. Journal of Economic Literature Classification Numbers: C78, D41, D51.
Higher loop effects in M(atrix) orbifolds

Abstract Scattering of zero-branes off the fixed point in R 8 / Z 2 as described by a super-quantum mechanics with eight supercharges, displays some novel effects relevant to Matrix theory in non-compact backgrounds. The leading long distance behaviour of the moduli space metric receives no correction at one loop in Matrix theory, but does receive a correction at two loops. There are no contributions at higher loops. We explicitly calculate the 2-loop term, finding a non-zero result. We find a discrepancy with M(atrix) theory. Although the result has the right dependence on ν and b for the scattering of zero-branes off the fixed point the factors of N do not match. We also discuss scattering in the orbifolds, R 5 / Z 2 and R 9 / Z 2 where we find the predicted fractional charges.
The persistence and inefficiency of property tax finance of local public expenditures

Abstract I both characterize and evaluate equilibrium outcomes in multiple-jurisdiction economies with property and land taxation but where direct taxation of residents is not possible. The model contains perfectly mobile capital and population, and competitive, entrepreneurial governments that choose local taxes and expenditures to maximize after-tax land rent. When the cost of public goods is proportional to population the property tax emerges as the sole source of local finance, even though the land tax has no deadweight loss. It is shown that equilibria are not constrained efficient in general; hence decentralized decision-making is not consistent with the best use of the available tax instruments.
Optimal locally repairable codes via rank-metric codes

This paper presents a new explicit construction for locally repairable codes (LRCs) for distributed storage systems which possess all-symbol locality and the largest possible minimum distance, or equivalently, can tolerate the maximum number of node failures. This construction, based on maximum rank distance (MRD) Gabidulin codes, provides new optimal vector and scalar LRCs. In addition, the paper also discusses mechanisms by which codes obtained using this construction can be used to construct LRCs with efficient local repair of failed nodes by combination of LRCs with regenerating codes.
Subjective probabilities on “small” domains

Abstract The Savagian choice-theoretic construction of subjective probability does not apply to preferences, like those in the Ellsberg Paradox, that reflect a distinction between risk and ambiguity. We formulate two representation results—one for expected utility, the other for probabilistic sophistication—that derive subjective probabilities but only on a “small” domain of risky events. Risky events can be either specified exogenously or in terms of choice behavior; in the latter case, both the values and the domain of probability are subjective. The analysis identifies a mathematical structure—called a mosaic—that is intuitive for both exogenous and behavioral specifications of risky events. This structure is weaker than an algebra or even a λ -system.
THE PROPAGATION OF UNCERTAINTIES IN STELLAR POPULATION SYNTHESIS MODELING. III. MODEL CALIBRATION, COMPARISON, AND EVALUATION

Stellar population synthesis (SPS) provides the link between the stellar and dust content of galaxies and their observed spectral energy distributions. In the present work, we perform a comprehensive calibration of our own flexible SPS (FSPS) model against a suite of data. These data include ultraviolet, optical, and near-IR photometry, surface brightness fluctuations, and integrated spectra of star clusters in the Magellanic Clouds (MCs), M87, M31, and the Milky Way (MW), and photometry and spectral indices of both quiescent and post-starburst galaxies at z {approx} 0. Several public SPS models are intercompared, including the models of Bruzual and Charlot (BC03), Maraston (M05), and FSPS. The relative strengths and weaknesses of these models are evaluated, with the following conclusions: (1) the FSPS and BC03 models compare favorably with MC data at all ages, whereas M05 colors are too red and the age dependence is incorrect; (2) all models yield similar optical and near-IR colors for old metal-poor systems, and yet they all provide poor fits to the integrated J - K and V - K colors of both MW and M31 star clusters; (3) FSPS is able to fit all of the ultraviolet data because both the post-asymptotic giant branch (post-AGB)more » and horizontal branch evolutionary phases are handled flexibly, while the BC03 and M05 models fail in the far-UV, and both far- and near-UV, respectively; (4) all models predict ugr colors too red, D{sub n}4000 strengths too strong, and Hdelta{sub A} strengths too weak compared to massive red sequence galaxies, under the assumption that such galaxies are composed solely of old metal-rich stars; and (5) FSPS and, to a lesser extent, BC03 can reproduce the optical and near-IR colors of post-starburst galaxies, while M05 cannot. Reasons for these discrepancies are explored. The failure at predicting the ugr colors, D{sub n}4000, and Hdelta{sub A} strengths can be explained by some combination of a minority population of metal-poor stars, young stars, blue straggler and/or blue horizontal branch (HB) stars, but not by appealing to inadequacies in either theoretical stellar atmospheres or canonical evolutionary phases (e.g., the main-sequence turnoff). The different model predictions in the near-IR for intermediate age systems are due to different treatments of the thermally pulsating asymptotic giant branch stellar evolutionary phase. We emphasize that due to a lack of calibrating star cluster data in regions of the metallicity-age plane relevant for galaxies, all of these models continue to suffer from serious uncertainties that are difficult to quantify.« less
Criminal stereotypes in the courtroom: Facial tattoos affect guilt and punishment differently.

Three studies using between-subjects designs examined the effect of facial tattoos on two stages of a courtroom trial. The presence of a facial tattoo affected judgments of guilt, but it did not lead to higher punishment ratings. This was the case for different types of crime varying in offense seriousness and for faces varying in perceived trustworthiness. The effect on guilt was fully mediated by the perceived criminal appearance of the tattooed defendant. These findings are the first that systematically address the question whether facial tattoos can bias legal outcomes. They further suggest that the psychological mechanisms by which an activated criminal stereotype influences legal judgments can differ for two stages of a trial. Policy implications are discussed.
NMR study of the influence of adsorbed sulfur on hydrogen chemisorption on supported ruthenium catalysts

Abstract NMR of hydrogen chemisorbed on silica-supported ruthenium catalysts was used to study the dissociation of H 2 S and its effect on subsequent hydrogen adsorption. A mixture of H 2 S/He was used to sulfide the reduced catalyst. The hydrogen coverages resulting from the dissociation of H 2 S as measured by NMR yielded estimates of sulfur coverages in good agreement with the results of X-ray fluorescence analysis of sulfur on the samples. The H 2 S dissociation reaction was found to be enhanced on higher dispersion catalysts suggesting an important role for defect-like sites. At sulfur coverages greater than 0.25 sulfur atoms per surface ruthenium atom, no hydrogen from the dissociation of H 2 S could be detected remaining on the surface. On the presulfided catalysts dosed to saturation with additional hydrogen, the NMR spectra revealed the presence of two species of hydrogen: a mobile species and a less mobile species. At sulfur coverages greater than 0.5 no detectable hydrogen could be adsorbed on the surface when exposed to 30 Torr of H 2 . The ratio of weakly bound hydrogen to the strongly bound hydrogen at saturation coverage decreased with increasing sulfur coverage. The small change in the magnitude of the NMR lineshift of hydrogen-on-metal with sulfur coverage suggested that the adsorbed sulfur does not induce a strong electronic effect on the chemisorption of hydrogen.
ALSEP: Quasar differential VLBI

A program of ALSEP-quasar very-long-baseline interferometry (VLBI) is being carried out. These observations employ primarily a 'four-antenna' technique whereby simultaneous observations with two antennas at each end of an intercontinental baseline are used to derive the differential interferometric phase between a compact extragalactic radio source (usually a quasar) and a number of ALSEP transmitters on the lunar surface. A continuous ALSEP-quasar differential phase history over a period of a few hours will lead to milliarcsecond angular accuracy in measuring the lunar position against the quasar reference frame if suitable calibration measurements are obtained. Development of this application of the four-antenna technique has been underway for more than a year and is producing high-quality data utilizing Deep Space Network stations. These high-accuracy observations are of value to tie the lunar ephemeris to a nearly inertial extragalactic reference frame, to test gravitational theories, and to measure the earth-moon tidal friction interaction.
Synthesis of glycosyl phosphates and azides

Abstract Anomerically enriched diphenyl hexopyranosyl phosphate triesters have been prepared from O -alkyl and -acylated hexopyranoses, using diphenyl chlorophosphate and 4- N,N -dimethylaminopyridine. Glycosyl phosphate triesters of d -gluco-, d -galacto, d -manno, 2-acetamido-2-deoxy- d -gluco-, l -fuco-, and l -rhamno-pyranosyl derivatives have been obtained by this procedure. At temperatures 0° and above, and under thermodynamic control, diphenyl glycosyl phosphates cis to the pyranosyl C-2-substituent are formed predominantly, whereas at low temperatures and under kinetic control, glycosyl phosphate triesters having 1,2- trans stereochemistry are obtained. The β-glycosyl phosphate triesters of d -glucose and d -galactose derivatives are unstable and undergo anomerization to the α-glycosyl phosphate triesters, in contrast to the stable β-phosphate derivatives of l -rhamnose and d -mannose. These phosphate triesters have been deprotected to glycosyl phosphate triethylammonium salts, suitable for the preparation of other key biological derivatives, such as nucleotide sugars. In addition, the diphenyl phosphate groups at the anomeric center have been displaced by azide to give the glycosyl azides, key intermediates in the synthesis of glycosyl amino acids.
Perturbation methods based upon varying action integrals

Abstract Direct perturbation solution procedures to non-linear systems are developed from variational statements derived from the principle of invariance of the action integral under infinitesimal transformations. Solution procedures that are the variational equivalent of the classical perturbation methods of strained parameters, the KBM method of averaging and the method of multiple time scales are presented.
Inflation targeting in an open financially integrated emerging economy: the case of Brazil

Este trabalho conduz algumas simulacoes da regra de Taylor ampliada (com a taxa de câmbio adicionada). Essas simulacoes foram feitas tambem para analisar choques externos em um modelo simples de Metas de Inflacao com equacoes de balanca comercial. Em contraste com Ball (2000), quando a taxa de câmbio e incluida na regra de Taylor, a volatilidade do produto aumenta apos um choque negativo no fluxo de capitais. Alem disso, o paper apresenta um estudo do pass-through da desvalorizacao da taxa de câmbio para a inflacao considerando a mudanca recente no regime das taxas de câmbio no Brasil. Estimativas econometricas foram feitas usando as especificacoes do pass-through sugeridas por Goldfajn e Werlang (2000).
Battery materials for ultrafast charging and discharging

The storage of electrical energy at high charge and discharge rate is an important technology in today's society, and can enable hybrid and plug-in hybrid electric vehicles and provide back-up for wind and solar energy. It is typically believed that in electrochemical systems very high power rates can only be achieved with supercapacitors, which trade high power for low energy density as they only store energy by surface adsorption reactions of charged species on an electrode material. Here we show that batteries which obtain high energy density by storing charge in the bulk of a material can also achieve ultrahigh discharge rates, comparable to those of supercapacitors. We realize this in LiFePO(4) (ref. 6), a material with high lithium bulk mobility, by creating a fast ion-conducting surface phase through controlled off-stoichiometry. A rate capability equivalent to full battery discharge in 10-20 s can be achieved.
A saturating lumped-parameter model for an interior PM synchronous machine

This paper presents a lumped-parameter magnetic model for an interior permanent-magnet synchronous machine. The model accounts for the effects of saturation through a nonlinear reluctance-element network used to estimate the q-axis inductance. The magnetic model is used to calculate inductance and torque in the presence of saturation. Furthermore, these calculations are compared to those from finite-element analysis with good agreement.
A Useful Approach to Primary Amines

Abstract Smooth reduction of acylsulfonamides to sulfonamides by borane, when coupled to standard sulfonamide cleavage procedures, provides a general route to primary amines.
A Mixed-Fidelity Approach for Design of Low-Boom Supersonic Aircraft *

This paper documents a mixed-fidelity approach for the design of low-boom supersonic aircraft as a viable approach for designing a pract ical low-boom supersonic configuration. A low-boom configuration that is based on low-fidelit y analysis is used as the baseline. Tail lift is included to help tailor the aft portion of the g round signature. A comparison of low- and high-fidelity analysis results demonstrates the nec essity of using computational fluid dynamics (CFD) analysis in a low-boom supersonic configuration design process. The fuselage shape is modified iteratively to obtain a configuration with a CFD equivalent-area distribution that matches a predetermined low-boom target distribution. The mixed-fidelity approach can easily refine the low-fidelity low-boo m baseline into a low-boom configuration with the use of CFD equivalent-area analysis. The g round signature of the final configuration is calculated by using a state-of-the -art CFD-based boom analysis method that generates accurate midfield pressure distributions for propagation to the ground with ray tracing. The ground signature that is propagated from a midfield pressure distribution has a shaped ramp front, which is similar to the ground s ignature that is propagated from the CFD equivalent-area distribution. This result confi rms the validity of the low-boom supersonic configuration design by matching a low-boom equivalent-area target, which is easier to accomplish than matching a low-boom midfield pressure target.
FIRST SCATTERED LIGHT IMAGES OF DEBRIS DISKS AROUND HD 53143 AND HD 139664

We present the first scattered light images of debris disks around a K star (HD 53143) and an F star (HD 139664) using the coronagraphic mode of the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). With ages of 0.3-1 Gyr, these are among the oldest optically detected debris disks. HD 53143, viewed ~45° from edge-on, does not show radial variation in disk structure and has a width >55 AU. HD 139664 is seen close to edge-on and has a beltlike morphology with a dust peak 83 AU from the star and a distinct outer boundary at 109 AU. We discuss evidence for significant diversity in the radial architecture of debris disks that appears unconnected to stellar spectral type or age. HD 139664 and possibly the solar system belong in a category of narrow belts 20-30 AU wide. HD 53143 represents a class of wide-disk architecture with a characteristic width >50 AU.
Green Markets and Private Provision of Public Goods

This paper develops a general model of private provision of a public good that includes the option to consume an impure public good. The model is used to investigate the positive and normative consequences of “green markets,” which are based on technologies with joint production of a private good and an environmental public good. It is shown that under reasonable conditions green markets can have beneficial or detrimental effects on environmental quality and social welfare. The analysis applies equally to nonenvironmental choice settings, with examples ranging from socially responsible investments to commercial activities associated with charitable fund‐raising.
Spectrally Selective Surfaces For High-Temperature Photothermal Solar Energy Conversion

A selective surface that absorbs the incident solar energy but suppresses its thermal reradiation can in some cases substantially improve the efficiency of a solar energy converter. In high-temperature applications, selective surfaces are shown to be most beneficial to systems using low or intermediate concentration ratios, although substantial economic savings can arise when used with large power systems having high concentration ratios. The optical performance and high temperature stability are discussed for coatings that rely on each of the five different methods for producing spectral selectivity. Each method has disadvantages as well as advantages, with most of the successful coatings using two or more of the methods. A particular coating that utilizes a silicon absorber over a silver reflector layer is described. The silicon is added by chemical vapor deposition (CVD) at elevated temperatures (>600°C). This is a unique application for CVD and has the potential for large-scale production in a flow-through system. At 500°C the solar absorptance and total normal emittance for these coatings are 0.76 and 0.07, respectively. They have withstood lifetime testing for 1000 hours of cycling (2/h) between 150°C and 450°C, plus 100 h continuously at 600°C with little degradation. Future improvements should allow the entire stack to be fabricated by CVD and at the same time achieve increases in both optical performance and high-temperature durability.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Quantum Hall exciton condensation at full spin polarization.

Using Coulomb drag as a probe, we explore the excitonic phase transition in quantum Hall bilayers at ν_T = 1 as a function of Zeeman energy E_Z. The critical layer separation (d/l)_c for exciton condensation initially increases rapidly with E_Z, but then reaches a maximum and begins a gentle decline. At high E_Z, where both the excitonic phase at small d/l and the compressible phase at large d/l are fully spin polarized, we find that the width of the transition, as a function of d/l, is much larger than at small E_Z and persists in the limit of zero temperature. We discuss these results in the context of two models in which the system contains a mixture of the two fluids.
Sigmoid-to-flux-rope Transition Leading to a Loop-like Coronal Mass Ejection

Sigmoids are one of the most important precursor structures for solar eruptions. In this Letter, we study a sigmoid eruption on 2010 August 1 with EUV data obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). In AIA 94 A (Fe XVIII; 6 MK), topological reconfiguration due to tether-cutting reconnection is unambiguously observed for the first time, i.e., two opposite J-shaped loops reconnect to form a continuous S-shaped loop, whose central portion is dipped and aligned along the magnetic polarity inversion line (PIL), and a compact loop crossing the PIL. A causal relationship between photospheric flows and coronal tether-cutting reconnections is evidenced by the detection of persistent converging flows toward the PIL using line-of-sight magnetograms obtained by the Helioseismic and Magnetic Imager on board SDO. The S-shaped loop remains in quasi-equilibrium in the lower corona for about 50 minutes, with the central dipped portion rising slowly at ~10 km s–1. The speed then increases to ~60 km s–1 about 10 minutes prior to the onset of a GOES-class C3.2 flare, as the S-shaped loop speeds up its transformation into an arch-shaped loop, which eventually leads to a loop-like coronal mass ejection. The AIA observations combined with Hα filtergrams as well as hard X-ray imaging and spectroscopy are consistent with most flare loops being formed by reconnection of the stretched legs of less-sheared J-shaped loops that envelopes the rising flux rope, in agreement with the standard tether-cutting scenario.
Scalability study of the KSR-1

Abstract Scalability of parallel architectures is an interesting area of current research. Shared memory parallel programming is attractive stemming from its relative ease in transitioning from sequential programming. However, there has been concern in the architectural community regarding the scalability of shared memory parallel architectures owing to the potential for large latencies for remote memory accesses. KSR-1 is a commercial shared memory parallel architecture, and the scalability of KSR-1 is the focus of this research. The study is conducted using a range of experiments spanning latency measurements, synchronization, and analysis of parallel algorithms for three computational kernels and an application. The key conclusions from this study are as follows: The communication network of KSR-1, a pipelined unidirectional ring, is fairly resilient in supporting simultaneous remote memory accesses from several processors. The multiple communication paths realized through this pipelining help in the efficient implementation of tournament-style barrier synchronization algorithms. Parallel algorithms that have fairly regular and contiguous data access patterns scale well on this architecture. The architectural features of KSR-1 such as the poststore and prefetch are useful for boosting the performance of parallel applications. The sizes of the caches available at each node may be too small for efficiently implementing large data structures. The network does saturate when there are simultaneous remote memory accesses from a fully populated (32 node) ring.