cssi/SciSciGPT-SciSciNet huggingface dataset:
Chandra Observations of the Interacting NGC 4410 Galaxy Group

We present high-resolution X-ray imaging data from the ACIS-S instrument on the Chandra telescope of the nearby interacting galaxy group NGC 4410. Four galaxies in the inner portion of this group are clearly detected by Chandra, including the peculiar low-luminosity radio galaxy NGC 4410A. In addition to a nuclear point source, NGC 4410A contains diffuse X-ray emission, including an X-ray ridge extending out to about 12'' (6 kpc) to the northwest of the nucleus. This ridge is coincident with an arc of optical emission-line gas, which has previously been shown to have optical line ratios consistent with shock ionization. This structure may be due to an expanding superbubble of hot gas caused by supernovae and stellar winds or by the active nucleus. The Chandra observations also show four or five possible compact ultraluminous X-ray (ULX) sources (LX ≥ 1039 ergs s-1) associated with NGC 4410A. At least one of these candidate ULXs appears to have a radio counterpart, suggesting that it may be due to an X-ray binary with a stellar-mass black hole, rather than an intermediate-mass black hole. In addition, a faint diffuse intragroup X-ray component has been detected between the galaxies (LX ~ 1041 ergs s-1). This supports the hypothesis that the NGC 4410 group is in the process of evolving via mergers from a spiral-dominated group (which typically has no X-ray–emitting intragroup gas) to an elliptical-dominated group (which often has a substantial intragroup medium).
Competing failure modes in accelerated life testing

There is a vast amount of literature on accelerated life testing, however, most of this literature ignores the possibility of competing modes of failure. The literature that attempts to address this problem often uses a maximum likelihood estimation method which may require large samples. Even in the case of a single failure mode, a small sample data is expected to be generated by an ALT procedure applied to expensive components. In this article we present a Bayesian framework for the analysis of ALT data with possible multiple failure modes. We illustrate the applicability of our model on some competing risk data sets available in the literature.
Supervisory Control of Dynamical Systems With Uncertain Time Delays

A study of controlling dynamical systems with uncertain and varying time delays is presented in this paper. The uncertain time delay is assumed to fall in a range with known upper and lower bounds. We apply the supervisory control algorithm to deal with uncertainties in the time delay. An index is defined for each of the predetermined controls for a discrete set of time delays sampled from the range. Based on this index, a hysteretic switching rule selects a control from the predetermined controls with optimal feedback gains. Each predetermined control must be stable for any time delay in the range. Two control design methods are discussed, namely, the mapping method and a higher order approach. Examples of linear systems are used to demonstrate the theoretical work.
Novel Methods for Multilinear Data Completion and De-noising Based on Tensor-SVD

In this paper we propose novel methods for completion (from limited samples) and de-noising of multilinear (tensor) data and as an application consider 3-D and 4- D (color) video data completion and de-noising. We exploit the recently proposed tensor-Singular Value Decomposition (t-SVD)[11]. Based on t-SVD, the notion of multilinear rank and a related tensor nuclear norm was proposed in [11] to characterize informational and structural complexity of multilinear data. We first show that videos with linear camera motion can be represented more efficiently using t-SVD compared to the approaches based on vectorizing or flattening of the tensors. Since efficiency in representation implies efficiency in recovery, we outline a tensor nuclear norm penalized algorithm for video completion from missing entries. Application of the proposed algorithm for video recovery from missing entries is shown to yield a superior performance over existing methods. We also consider the problem of tensor robust Principal Component Analysis (PCA) for de-noising 3-D video data from sparse random corruptions. We show superior performance of our method compared to the matrix robust PCA adapted to this setting as proposed in [4].
Cosmic conclusions from climatic models: Can they be justified?

Abstract Climatic models are increasingly being used to answer “cosmic questions” such as the possibility of an ice-covered Earth or a runaway greenhouse effect, or to examine the coevolution of climate and life. Conclusions from these models on such issues, of course, rest on the physical parameterizations of the models. Some of the basic parameterizations are reexamined quantitatively, and it is concluded that presently believed uncertainties in these parameterizations lead to an order-of-magnitude uncertainty in estimates of the sensitivity of the present Earth's climate to external forcings (like a change in solar constant). However, seasonal simulations with present Earth models suggest that estimates of the overall sensitivity of the climate to external forcing may be narrowed (over decadal time scales) to, perhaps, a factor of 2. But the effects of glaciers, continental locations, and atmospheric composition, all of which can change on geological time scales, further enhance the uncertainties in long-term climatic sensitivity estimates from state-of-the-art models. But it is precisely these long-term estimates of climatic sensitivity which support quantitative conclusions on, for example, the possible existence of continuously habitable zones around main-sequence stars. We believe that those who draw cosmic conclusions from climatic models should at least attempt to bracket the final results by repeating their calculations over a plausible range of uncertainty in basic model parameterizations.
Nuclear physics on the light front

High energy scattering experiments involving nuclei are typically analyzed in terms of light front variables. The desire to provide realistic, relativistic wave functions expressed in terms of these variables led me to try to use light front dynamics to compute nuclear wave functions. The progress is summarized here.
Estimation of Mittag-Leffler Parameters

We propose a procedure for estimating the parameters of the Mittag-Leffler (ML) and the generalized Mittag-Leffler (GML) distributions. The algorithm is less restrictive, computationally simple, and necessary to make these models usable in practice. A comparison with the fractional moment estimator indicated favorable results for the proposed method.
Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure

A stable and reproducible superconductivity transition between 80 and 93 K has been unambiguously observed both resistively and magnetically in a new Y-Ba-Cu-O compound system at ambient pressure. An estimated upper critical field H c2(0) between 80 and 180 T was obtained.
Leading, Following or Cooked Goose? Innovation Successes and Failures in Taiwan's Electronics Industry

The reasons behind the innovation successes and failures in the Taiwanese electronics industry have been widely discussed. This paper makes its contribution to the debate by comparing the innovation outcomes for three products: complimentary metal oxide silicon (CMOS) logic, dynamic random access memory (DRAM) and active matrix liquid crystal displays (AMLCDs). Four success factors are identified to characterize products where the Taiwanese pursue innovation: granularity of production; absence of need for large amounts of patient capital; volume production; and manufacturing-based production. In turn, this paper argues that products exhibiting these characteristics succeed because such characteristics draw upon the institutional and historical strengths of the Taiwanese economy. The paper broadens the inquiry to assess what lessons the Taiwanese innovation successes have for developing countries. It is argued that the new lesson Taiwan has to offer is that countries can become innovators by concentrating ...
Procedural semantics for a question-answering machine

Simmons has presented a survey of some fifteen experimental question-answering and related systems which have been constructed since 1959. These systems take input questions in natural English (subject to varying constraints) and attempt to answer the questions on the basis of a body of information, called the data base, which is stored inside the computer. This process can be conceptually divided into three phases---syntatic analysis, semantic analysis, and retrieval, as illustrated schematically in Figure 1. The first phase consists of parsing the input sentence into a structure which explicitly represents the grammatical relationships among the words of the sentence. Using this information the second component constructs a representation of the semantic content or "meaning" of the sentence. The remaining phase consists of procedures for either retrieving the answer directly from the data base, or else deducing the answer from information contained in the data base. The dotted lines in the figure represent the possible use of feedback from the later stages to aid in parsing and semantic interpretation.
Virtual Yang-Baxter cocycle invariants

We extend the Yang-Baxter cocycle invariants for virtual knots by augmenting Yang-Baxter 2-cocycles with cocycles from a cohomology theory associated to a virtual biquandle structure. These invariants coincide with the classical Yang-Baxter cocycle invariants for classical knots but provide extra information about virtual knots and links. In particular, they provide a method for detecting non-classicality of virtual knots and links.
Beyond the Frenkel-Kac-Segal construction of affine Lie algebras

Abstract This contribution reviews recent progress in constructing affine Lie algebras at arbitrary level in terms of vertex operators. The string model describes a completely compactified subcritical chiral bosonic string whose momentum lattice is taken to be the (Lorentzian) affine weight lattice. The main feature of the new realization is the replacement of the ordinary string oscillators by physical DDF operators, whereas the unphysical position operators are substituted by certain linear combinations of the Lorentz generators. As a side result we obtain simple expressions for the affine Weyl translations as Lorentz boosts. Various applications of the consdtruction are discussed.
Some electronic printer metrics

Electronic printing is now 25 years old. A great deal of progress has been made as evidenced by the great number of electronic printers and their associated technologies. This paper illustrates three simple metrics with which to analyze electronic printer technology. The metrics are not necessarily intended to be anything profound or deterministic but appear to illustrate some relative constants as well as significant improvements in printers that indicate a trend whose final outcome is yet to be seen. Since electronic printers are basically information delivery devices, they can be analyzed as to their information delivery capability on a cost-performance basis. The three metrics utilized in this paper involve a number of characteristics such as printer weight, speed, spatial printing density and color. Over 170 printers area used in this analysis dating from the birth of the laser printer in the mid-1970s up to the present time. This metric oriented view of the technology may give us some insight as to where the electronic printing industry is going on a cost/performance basis as well as where new products should be aimed so that they provide the desired market impact.
Joint Attention and Toddler Characteristics: Race, Sex and Socioeconomic Status∗

In studies of joint attention and sequences of interaction that foster joint attention, limited focus has been placed on toddler characteristics such as race, sex and socioeconomic status (SES). The purpose of the present study was to investigate the relationship between joint attention and toddler's race, sex and SES. Eighty‐four dyads of diverse race, sex and SES were videotaped playing, and joint attention and initiating matemal bid sequences were coded. Joint attention related to a “persisting” mother, whether or not the toddler accepted the initial maternal bid. No race differences were found; however, females engaged in more frequent bouts of joint attention and had more frequent nonpersistent maternal responses after the bid was accepted. Finally, SES was generally unrelated to joint attention. The manner in which bids for joint attention transpired and the amount of joint attention that occurred was largely independent of the dyad's SES as measured here. ∗This research was funded by a university r...
The Influence of Atmospheric Dynamics on the Infrared Spectra and Light Curves of Hot Jupiters

We explore the infrared spectrum of a three-dimensional dynamical model of planet HD 209458b as a function of orbital phase. The dynamical model predicts dayside atmospheric pressure-temperature profiles that are much more isothermal at pressures less than 1 bar than one-dimensional radiative-convective models have found. The resulting dayside thermal spectra are very similar to a blackbody, and only weak water absorption features are seen at short wavelengths. The dayside emission is consequently in better agreement with ground-based and space-based secondary eclipse data than any previous models, which predict strong flux peaks and deep absorption features. At other orbital phases, absorption due to carbon monoxide and methane is also predicted. We compute the spectra under two treatments of atmospheric chemistry: one uses the predictions of equilibrium chemistry, and the other uses nonequilibrium chemistry, which ties the timescales of methane and carbon monoxide chemistry to dynamical timescales. As a function of orbital phase, we predict planet-to-star flux ratios for standard infrared bands and all Spitzer Space Telescope bands. In Spitzer bands, we predict two- to fifteenfold variation in planetary flux as a function of orbital phase with equilibrium chemistry, and two- to fourfold variation with nonequilibrium chemistry. Variation is generally more pronounced in bands from 3 to 10 � m than at longer wavelengths. The orbital phase of maximum thermal emission in infrared bands is 15Y45 orbital degrees before the time of secondary eclipse. Changes influx as a function of orbital phase for HD 209458b should be observable with Spitzer, given the previously achieved observational error bars. Subject headingg binaries: eclipsing — planetary systems — radiative transfer — stars: individual (HD 209458)
The relationship between knowledge, belief, and certainty

We consider the relation between knowledge and certainty, where a fact isknown if it is true at all worlds an agent considers possible and iscertain if it holds with probability 1. We identify certainty with belief, interpreted probabilistically. We show that if we assume one fixed probability assignment, then the logic KD45, which has been identified as perhaps the most appropriate for belief, provides a complete axiomatization for reasoning about certainty. Just as an agent may believe a fact althoughϕ is false, he may be certain that a factϕ is true althoughϕ is false. However, it is easy to see that an agent can have such false (probabilistic) beliefs only at a set of worlds of probability 0. If we restrict attention to structures where all worlds have positive probability, then S5 provides a complete axiomatization. If we consider a more general setting, where there might be a different probability assignment at each world, then by placing appropriate conditions on thesupport of the probability function (the set of worlds which have non-zero probability), we can capture many other well-known modal logics, such as T and S4. Finally, we considerMiller's principle, a well-known principle relating higher-order probabilities to lower-order probabilities, and show that in a precise sense KD45 characterizes certainty in those structures satisfying Miller's principle.
Time ordering and the thermodynamics of strange sets: Theory and experimental tests.

From the spectrum of dimensions of a fractal invariant measure of a dynamical system one can extract information about the dynamical process that gave rise to the measure. This is equivalent to finding the class of Hamiltonians of an Ising model with a given thermodynamics.
Spectrodetector: Novel monolithic wavelength reader and photodetector

A novel compact monolithic wavelength reader and photodetector is demonstrated for the first time. The device consists of two back-to-back detectors with a wavelength dependent distributed Bragg reflector in between, and has a spectral range of 40 nm and a resolution of 1 nm.
Flux-vacua in two dimensional string theory

We analyze the two dimensional type 0 theory with background RR-fluxes. Both the 0A and the 0B theory have two distinct fluxes q and . We study these two theories at finite temperature (compactified on a euclidean circle of radius R) as a function of the fluxes, the tachyon condensate μ and the radius R. Surprisingly, the dependence on q, and μ is rather simple. The partition function is the absolute value square of a holomorphic function of y = |q|+||+i(2α')1/2μ (up to a simple but interesting correction). As expected, the 0A and the 0B answers are related by T-duality. Our answers are derived using the exact matrix models description of these systems and are interpreted in the low energy spacetime lagrangian.
General relativity at 75: how right was einstein?

The status of experimental tests of general relativity is reviewed on the occasion of its 75th anniversary. Einstein's equivalence principle is well supported by experiments such as the Eotvos experiment, tests of special relativity, and the gravitational redshift experiment. Tests of general relativity have reached high precision, including the light deflection and the perihelion advance of Mercury, proposed by Einstein 75 years ago, and new tests such as the Shapiro time delay and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected to an accuracy of 1 percent on the basis of measurements of the binary pulsar. The status of the "fifth force" is discussed, along with the frontiers of experimental relativity, including proposals for testing relativistic gravity with advanced technology and spacecraft.
Design and Preliminary Results of a Fuel Flexible Industrial Gas Turbine Combustor

The emphasis in this paper is the fuel flexible combustor technology developed under the ''Low Nitric Oxide Heavy Fuel Combustor Concept Program'' for application to the Detroit Diesel Allison (DDA) Model 570-K industrial gas turbine engine. The technology, to achieve emission goals, emphasizes dry Nitric Oxide reduction methods. 13 refs.
An integrated assessment of the effects of Title I on school behavior, resources, and student achievement

Abstract We examine the effects of Title I on school behavior, resources, and academic performance using a rich set of school finance and student-level achievement data from one large urban school district using a regression discontinuity design. We find that Title I eligibility raises Federal revenues of schools by about $460 per student. This is partially offset by decreases in revenues from state categorical aid grants, so that the net increase to schools is about $360 per student. We find no impact on overall school-level test scores, but also no impact among the subgroups of students most likely to be affected by Title I. A novel finding is that schools appear to respond to the incentives embedded in the Title I allocation process by manipulating the fraction of their students signed up for free lunch to secure more Federal funds.
On Throughput Optimality With Delayed Network-State Information

The problem of routing/scheduling in a wireless network with partial/delayed network (channel and queue) state information (NSI) is studied in this paper. Two cases are considered: (i) centralized routing/scheduling, where a central controller obtains heterogeneously delayed information from each of the nodes (thus, the controller has NSI with different delays from different nodes), and makes routing/scheduling decisions; (ii) decentralized routing/scheduling, where each node makes a decision based on its current channel and queue states along with homogeneous delayed NSI from other nodes. For each of the cases (with additional flow restrictions for the decentralized routing/scheduling case), the optimal network throughput regions are characterized under the above described NSI models and it is shown that the throughput regions shrinks with the increase of delay. Further, channel and queue length based routing/scheduling algorithms that achieve the above throughput regions are proposed in this paper.
L AND T DWARF MODELS AND THE L TO T TRANSITION

Using a model for refractory clouds, a novel algorithm for handling them, and the latest gas-phase molecular opacities, we have produced a new series of L and T dwarf spectral and atmosphere models as a function of gravity and metallicity, spanning the Teff range from 2200 to 700 K. The correspondence with observed spectra and infrared colors for early and mid-L dwarfs and for mid- to late T dwarfs is good. We find that the width in infrared color-magnitude diagrams of both the T and L dwarf branches is naturally explained by reasonable variations in gravity and therefore that gravity is the ``second parameter" of the L-T dwarf sequence. We investigate the dependence of theoretical dwarf spectra and color-magnitude diagrams on various cloud properties, such as particle size and cloud spatial distribution. In the region of the L → T transition, we find that no single combination of cloud particle size and gravity can be made to fit all the observed data. Our results suggest that current ignorance of detailed cloud meteorology renders ambiguous the extraction of various physical quantities such as Teff and gravity for mid-L to early T dwarfs. Nevertheless, for decreasing Teff, we capture with some accuracy the major spectral features and signatures observed. We speculate that the subdwarf branch of the L dwarfs would be narrower in effective temperature and that for low enough metallicity the L dwarfs would disappear altogether as a spectroscopic class. Furthermore, we note that the new, lower solar oxygen abundances of Allende-Prieto and coworkers produce better fits to brown dwarf data than do the older values. Finally, we discuss various issues in cloud physics and modeling and speculate on how a better correspondence between theory and observation in the problematic L → T transition region could be achieved.
How Accurately Do We Know the Formation of Solar 8B

A detailed examination of current data on S17 (as opposed to an examination of S 17 ( 0 ) only) excludes quoting S 17 ( 0 ) with sufficiently small uncertainty. In contrast to suggestions that S 17 ( 0 ) is now known with the accuracy of ±3%, the exact value of S 17 ( 0 ) is dependent on the choice of the data and the choice of theory used for extrapolation. In addition recent high precision results (including the Seattle data) on S 17 which are in good agreement, still differ on the measured slopes, as do theoretical models that predict different d-wave contribution, precluding an accurate extrapolation to zero energy of the consistent data. Using a common extrapolation of only the consistent high precision data, suggests a value of S 17 ( 0 ) = 21.2 ± 0.5 eV-b , but a value equal to or smaller than 19.0 eV-b can not be excluded due to the uncertainty in the extrapolation, leading to an additional error of −3.0 +0.0 eV-b . This (unacceptable) situation must be cleared by future experiments.
An Average Slope Factor for Solar Insolation

Design methods for solar collector sizing (such as f-chart) usually require a multiplying factor (the slope factor) to correct insolation data taken on the horizontal for the tilt angle of the solar collector. Available slope factor data were averaged and were re-plotted to result in a chart whose parameters are latitude and month of year. Correction charts for off-average locations are presented. The error in the given standard slope factor chart is estimated to be accurate + or - 5 percent for many cities.
Combinatorics of balanced carries

We study the combinatorics of addition using balanced digits, deriving an analog of Holte's ''amazing matrix'' for carries in usual addition. The eigenvalues of this matrix for base b balanced addition of n numbers are found to be 1,1/b,...,1/b^n, and formulas are given for its left and right eigenvectors. It is shown that the left eigenvectors can be identified with hyperoctahedral Foulkes characters, and that the right eigenvectors can be identified with hyperoctahedral Eulerian idempotents. We also examine the carries that occur when a column of balanced digits is added, showing this process to be determinantal. The transfer matrix method and a serendipitous diagonalization are used to study this determinantal process.
Why do individuals choose defined contribution plans? Evidence from participants in a large public plan

Abstract We examine individual choices between a defined contribution (DC) and a defined benefit (DB) retirement plan at a large public employer. We find sensible patterns with regard to standard economic and demographic factors: the probability of choosing the DC plan decreases with the relative financial generosity of the DB plans versus the DC plan and rises with education and income. Using a survey of participants, we find that the ability to control for beliefs, preferences, and other variables not easily obtainable from administrative or standard household surveys increases the explanatory power over seven-fold. Among the important factors in the DB/DC pension choice are respondent attitudes about risk/return tradeoffs, financial literacy, return expectations, and political risk. We also find that individuals make sensible choices based on what they believe to be true about the plans, but that these beliefs about plan parameters are often wrong, thus leading to possibly sub-optimal decisions. Finally, we provide evidence that individuals' preferences over plan attributes (e.g., the degree of control provided) are even more important determinants of the DB/DC decision than expected outcomes (e.g., the relative generosity of the plans).
FIRST RESULTS FROM Pan-STARRS1: FAINT, HIGH PROPER MOTION WHITE DWARFS IN THE MEDIUM-DEEP FIELDS

The Pan-STARRS1 survey has obtained multi-epoch imaging in five bands (Pan-STARRS1 g P1, r P1, i P1, z P1, and y P1) on 12 "Medium-Deep fields," each of which spans a 33 circle. For the period between 2009 April and 2011 April these fields were observed 50-200 times. Using a reduced proper motion diagram, we have extracted a list of 47 white dwarf (WD) candidates whose Pan-STARRS1 astrometry indicates a non-zero proper motion at the 6σ level, with a typical 1σ proper motion uncertainty of 10 mas yr–1. We also used astrometry from the Sloan Digital Sky Survey (when available) and USNO-B to assess our proper motion fits. None of the WD candidates exhibits evidence of statistically significant parallaxes, with a typical 1σ uncertainty of 8 mas. Twelve of these candidates are known WDs, including the high proper motion (17 yr–1) WD LHS 291. We confirm seven more objects as WDs through optical spectroscopy. Based on the Pan-STARRS1 colors, ten of the stars are likely to be cool WDs with 4170 K <T eff < 5000 K and cooling ages ≈ 8 Gyr. Based on their kinematics, these objects are likely thick disk WDs, but a subset may belong to the halo. Our current sample represents only a small fraction of the Pan-STARRS1 data. With continued coverage from the Medium-Deep Field Survey and the 3π survey, Pan-STARRS1 should find many more high proper motion WDs that are part of the old thick disk and halo.
Flexibility, turnover and training

Addresses the question of whether a high turnover of staff is accompanied by lower investment in company‐training. By means of a written questionnaire, data were collected from 223 companies in four different sectors: the food sector, the wholesale trade, the printing industry and the software sector. Besides the turnover of staff, introduces the degree of contractual flexibility and the existence of an internal labour market as explanatory variables in the discussion. In contradiction to most labour economic thinking on training, finds a positive relationship between fluctuations in the number of employees and the investment in training. The findings indicate that company training is particularly concentrated on inflow and replacement problems. Therefore, concludes that financial support measures of governments might benefit more the recruitment policy of companies instead of the high ideal of “lifelong learning”.
Organic chemistry: Reactivity tamed one bond at a time

A catalyst that couples together three reactants to form just one compound out of several possibilities, as a single mirror-image isomer, should simplify the synthesis of biologically relevant molecules. See Article p.367 This paper reports a catalytic process that combines two simple unsaturated organic molecules — a highly selective copper–diboron reagent and a monosubstituted allene — to produce a boron-substituted organocopper intermediate that then participates in a chemoselective, site-selective and enantioselective allylic substitution. The authors use this approach in the enantioselective synthesis of gram quantities of two natural products: the anti-tumour agent herboxidiene and stereoisomerically pure rottnestol, a hemiketal originally isolated from a marine sponge. Further development of this procedure should lead to economical protocols for the synthesis of other difficult-to-access alkenylboron-containing organocopper compounds.
Long-Term X-Ray Variability of Circinus X-1

We present an analysis of long term X-ray monitoring observations of Circinus X-1 (Cir X-1) made with four different instruments: Vela 5B, Ariel V ASM, Ginga ASM, and RXTE ASM, over the course of more than 30 years. We use Lomb-Scargle periodograms to search for the approx. 16.5 day orbital period of Cir X-1 in each of these data sets and from this derive a new orbital ephemeris based solely on X-ray measurements, which we compare to the previous ephemerides obtained from radio observations. We also use the Phase Dispersion Minimization (PDM) technique, as well as FFT analysis, to verify the periods obtained from periodograms. We obtain dynamic periodograms (both Lomb-Scargle and PDM) of Cir X-1 during the RXTE era, showing the period evolution of Cir X-1, and also displaying some unexplained discrete jumps in the location of the peak power.
Formation of N-alkylpyrroles via intermolecular redox amination.

A wide variety of aldehydes, ketones, and lactols undergo redox amination when allowed to react with 3-pyrroline in the presence of a mild Bronsted acid catalyst. This reaction utilizes the inherent reducing power of 3-pyrroline to perform the equivalent of a reductive amination to form alkyl pyrroles. In doing so, the reaction avoids stoichiometric reducing agents that are typically associated with reductive aminations. Moreover, the redox amination protocol allows access to alkyl pyrroles that cannot be made via standard reductive amination.
Nonlinear RR Lyrae models with new livermore opacities

A. N. Cox recently showed that a 20% opacity decrease in the 20,000–30.000 K region as indicated by the new Livermore OPAL opacities reconciles the discrepancy between pulsation and evolution masses of double-mode RR Lyrae variables. Nonlinear hydrodynamic calculations were performed for RR Lyrae models of mass 0.75M ⊙, 51L ⊙, and Z = 0.0001 (Osterhoff II type) including this opacity decrease. The Stellingwerf periodic relaxation method was used to converge the models to a limit cycle, and the Floquet matrix eigenvalues calculated to search for a tendency of the fundamental mode to grow from the full-amplitude overtone solution, and the overtone mode to grow from the full-amplitude fundamental solution, thereby predicting double-mode behavior. Models of T eff 7000 have positive 1st overtone growth rates in the fundamental-mode solution, but double-mode behavior was not found.
Synthesis of multisulfur‐containing substituted dibenzothiophenes

New substituted dibenzothiophenes have been prepared and characterized. Selective functionalizations utilized substitutions of lithiodibenzothiophenes available from established methodology. New dibenzothiophenes prepared include 2-(bromomethyl)dibenzothiophene (5), 2-(thiomethyl)dibenzothiophene (6), 2-S-phenylthiomethyldibenzothiophene (24), 2-S-(2′-dibenzothiophenylmethyl)thiomethyldibenzothiophene (25), 2-S-methyldibenzothiophene (30), 2-S-(p-bromophenyl)dibenzothiophene (31), and 2-S-benzyldibenzothiophene (33). Dibenzothiophenes prepared from 4-lithiodibenzothiophene include 4-(bromomethyl)dibenzothiophene (13), 4-(thiomethyl)dibenzothiophene (14), 4-S-(4′-dibenzothiophenylmethyl)thiomethyldibenzothiophene (26), 4-S-(p-tolyl)dibenzothiophene (34), 4-S-methyldibenzothiophene (35), 4-S-benzyldibenzothiophene (37), and 4-S-(p-bromophenyl)dibenzothiophene (36). Similarly new 2,8-disubstituted dibenzothiophenes prepared include 2,8-bis(thiomethyl)dibenzothiophene (19), 2,8-bis(S-benzyl)dibenzothiophene (27), 2,8-bis(S-p-tolyl)dibenzothiophene (28) and 2,8-bis(S-methyl)dibenzothiophene (29). The cmr chemical shift data for these dibenzothiophenes are also included.
Physical organic chemistry on the brain.

The challenges to obtaining chemical-scale information on the molecules of neuroscience are considerable. Most targets are complex integral membrane proteins that are not amenable to direct structural characterization. However, by combining the tools of organic synthesis, molecular biology, and electrophysiology, rational and systematic structure−function studies can be performed in what we have termed physical organic chemistry on the brain. Using these tools, we have probed hydrophobic effects, hydrogen bonding, cation−π interactions, and conformational changes associated with channel gating. The insights gained provide important guidance for drug discovery efforts targeting ion channels and neuroreceptors and mechanistic insights for the complex proteins of neuroscience.
Chemoselective catalytic hydrogenation of alkenes by Lindlar catalyst

Commercially available Lindlar catalyst (10% by weight) in methanol, selectively hydrogenates various alkenes in the presence of benzyl ether and benzyl amine functionalities.
Fermionic one-loop corrections to soliton energies in 1+1 dimensions

Abstract We demonstrate an unambiguous and robust method for computing fermionic corrections to the energies of classical background field configurations. We consider the particular case of a sequence of background field configurations that interpolates continuously between the trivial vacuum and a widely separated soliton/antisoliton pair in 1+1 dimensions. Working in the continuum, we use phase shifts, the Born approximation, and Levinson's theorem to avoid ambiguities of renormalization procedure and boundary conditions. We carry out the calculation analytically at both ends of the interpolation and numerically in between, and show how the relevant physical quantities very continuously. In the process, we elucidate properties of the fermionic phase shifts and zero-modes.
On the Mechanism of Multi-Valued Friction in Unsteady Sliding Line Contacts Operating in the Regime of Mixed-Film Lubrication

Systematic analyses are presented to reveal the mechanism of multi-valued friction behavior in lubricated sliding contacts with time-varying velocities. The analyses are based on the theoretical results generated by a mixed-film friction model developed in this paper for line contacts. The model, which integrates theories of transient elastohydrodynamics and asperity contact mechanics, is validated by comparing its results with published experimental data. The results and the subsequent analyses disclose that strong multi-valued friction behavior can only be generated in the mixed-film lubrication regime with simultaneous presence of significant asperity contacts and hydrodynamic squeeze. Principal factors which influence the magnitude of dynamic friction are investigated in the paper. Being instructive to the design of tribo-contacts in precise-motion control systems, the analyses suggest means to minimize the undesirable multi-valued friction behavior through proper selection of system parameters.
THE PHYSICAL PROPERTIES OF HD 3651B: AN EXTRASOLAR NEMESIS?

I present detailed analysis of the near-infrared spectrum of HD 3651B, a faint, comoving wide companion to the nearby planet-hosting star HD 3651. These data confirm the companion as a brown dwarf with spectral type T8, consistent with the analysis of Luhman et al. Application of the semi-empirical technique of Burgasser, Burrows, & Kirkpatrick indicates that HD 3651B has Teff = 790 ? 30 K and log g = 5.0 ? 0.3 for a metallicity of [M/H] = 0.12 ? 0.04, consistent with a mass M = 0.033 ? 0.013 M? and an age of 0.7-4.7 Gyr. The surface gravity, mass, and age estimates of this source are all highly sensitive to the assumed metallicity; however, a supersolar metallicity is deduced by direct comparison of spectral models to the observed absolute fluxes. The age of HD 3651B is somewhat better constrained than that of the primary, with estimates for the latter ranging over ~2 Gyr to >12 Gyr. As a widely orbiting massive object to a known planetary system that could potentially harbor terrestrial planets in its habitable zone, HD 3651B may play the role of Nemesis in this system.
Non-Fermi liquids from holography

We report on a potentially new class of non-Fermi liquids in (2+1)-dimensions. They are identified via the response functions of composite fermionic operators in a class of strongly interacting quantum field theories at finite density, computed using the AdS/CFT correspondence. We find strong evidence of Fermi surfaces: gapless fermionic excitations at discrete shells in momentum space. The spectral weight exhibits novel phenomena, including particle-hole asymmetry, discrete scale invariance, and scaling behavior consistent with that of a critical Fermi surface postulated by Senthil.
Class hierarchy specialization

Many class libraries are designed with an emphasis on generality and extensibility. Applications often exercise only part of a library's functionality. As a result, the objects created by an application may contain unused (user-specified or compiler-generated) members. Redundant members in objects are undesirable because they increase an application's memory usage. We present an algorithm for specializing a class hierarchy with respect to its usage in a program $\cal P$ . That is, the algorithm analyzes the member access patterns for $\cal P$ 's variables, and creates distinct classes for variables that access different members. The algorithm addresses the inheritance mechanisms of C++ in their full generality, including multiple inheritance and virtual (shared) inheritance. Class hierarchy specialization reduces object size, and can be viewed as a space optimization. However, execution time may also be reduced through reduced object creation or destruction time, and caching and paging effects. Class hierarchy specialization may also create new opportunities for existing optimizations such as call devirtualization and inlining. In addition, specialization may be useful in tools for software maintenance and program understanding.
Characterization and Ammonia Synthesis Activity of Ruthenium Zeolite Catalysts

Ruthenium metal in a series of alkali-metal-exchanged faujasite-type zeolites was found to be active for the catalytic synthesis of ammonia from dihydrogen and dinitrogen at temperatures between 300 and 450°C and at atmospheric pressure. A triply promoted iron catalyst exhibited a lower activity under similar conditions. Following reduction in hydrogen, the ruthenium metal crystallites were located within the pore structure of the zeolite microcrystals. Variation of the exchangeable alkali-metal cations and the silicon-to-aluminum ratio altered the activity of the ruthenium catalysts, with RuKX being the most active material. By applying Sanderson′s electronegativity calculations to the ruthenium zeolites, a relationship was found between the turnover frequency for ammonia synthesis and the effective oxygen charge, which was a function of the cation and the Si/Al ratio. Presumably negative charge is transferred from the oxygen to the metal, thereby enhancing the rate of N2 dissociation. The metal particle size also influenced the activity; larger particles were more active. A RuHY zeolite was the least active among the catalysts studied.
Distortion compensation for generalized stereoscopic particle image velocimetry

Optical distortion due to inaccurate optical alignment, lens nonlinearity, and/or refraction by optical windows, fluid interfaces, and other optical elements of an experiment causes inaccuracy by introducing variable magnification. Since fractional changes in the magnification have a one-to-one effect on the accuracy of measuring the velocity, it is important to compensate for such distortions. A general experimental calibration procedure is described which determines the magnification matrix of a distorted imaging system, and an algorithm is presented to compute accurate velocity field displacements from measurements of distorted PIV images. These procedures form a basis for generalized stereoscopic PIV procedures which permit easy electronic registration of multiple cameras and accurate recombination of stereoscopic displacement fields to obtain the three-dimensional velocity vector field.
A cut-off phenomenon in location based random access games with imperfect information

This paper analyzes the behavior of selfish transmitters under imperfect location information. The scenario considered is that of a wireless network consisting of selfish nodes that are randomly distributed over the network domain according to a known probability distribution, and that are interested in communicating with a common sink node using common radio resources. In this scenario, the wireless nodes do not know the exact locations of their competitors but rather have belief distributions about these locations. Firstly, properties of the packet success probability curve as a function of the node-sink separation are obtained for such networks. Secondly, a monotonicity property for the best-response strategies of selfish nodes is identified. That is, for any given strategies of competitors of a node, there exists a critical node-sink separation for this node such that its best-response is to transmit when its distance to the sink node is smaller than this critical threshold, and to back off otherwise. Finally, necessary and sufficient conditions for a given strategy profile to be a Nash equilibrium are provided.
SUSY GUT model building

The evolution of SUSY GUT model building is discussed, starting with the construction of 4D GUTs, to orbifold GUTs and finally to orbifold GUTs, within the heterotic string model. This evolution is an attempt to obtain realistic string models, perhaps relevant for the LHC. This review is in memory of the sudden loss of Julius Wess, a leader in the field, who will be sorely missed.
Helicity of the W in Single-Lepton $t\bar{t}$ Events

We have developed a procedure to study the helicity of the W boson in events. Using events generated with the PYTHIA program at a top Mt = 175 GeV/c2, we employ a maximum likelihood method to extract the fraction of right-handed, longitudinal and left-handed W bosons in top decays. Assuming V–A coupling in the decay, we obtain a longitudinal fraction of 0.696±0.097 for 50 simulated experiments of 100 events in lepton+jets final states, a result that is consistent with the input fraction of 0.703.
Stability of exact solutions of the defocusing nonlinear Schrödinger equation with periodic potential in two dimensions

Abstract The cubic nonlinear Schrodinger equation with repulsive nonlinearity and elliptic function potential in two-dimensions models a repulsive dilute gas Bose–Einstein condensate in a lattice potential. A family of exact stationary solutions is presented and its stability is examined using analytical and numerical methods. All stable trivial-phase solutions are off-set from the zero level. Our results imply that a large number of condensed atoms is sufficient to form a stable, periodic condensate.
An Experimental Verification of Laser-Velocimeter Sampling Bias and Its Correction

The existence of 'sampling bias' in individual-realization laser velocimeter measurements is experimentally verified and shown to be independent of sample rate. The experiments were performed in a simple two-stream mixing shear flow with the standard for comparison being laser-velocimeter results obtained under continuous-wave conditions. It is also demonstrated that the errors resulting from sampling bias can be removed by a proper interpretation of the sampling statistics. In addition, data obtained in a shock-induced separated flow and in the near-wake of airfoils are presented, both bias-corrected and uncorrected, to illustrate the effects of sampling bias in the extreme.
Analysis of efficient markets

A simple trading model is presented in which Bayes’ rule is used to aggregate traders’ forecasts about risky assets’ future returns. In this financial market, Bayes’ rule operates like an omnipotent market-maker performing functions that in 1776 Adam Smith attributed to an “invisible hand.” We have analyzed two distinct cases: in the first scenario, the traders’ forecast errors are uncorrelated, and in the second scenario, the traders’ forecast errors are correlated. The contribution of our paper is fourfold: first, we prove that the “efficient market” mean-return can be expressed as a complex linear combination of the traders’ forecasts. The weights depend on the forecast variances, as well as on the correlations among the traders’ forecasts. Second we show that the “efficient” variance is equal to the inverse of the sum of the traders’ precision errors, and is also related to the correlations among the traders’ forecast errors. Third, we prove that the efficient market return is the best linear minimum variance estimator (BLMVE) of the security’s mean return (in the sense that it minimizes the sum of the traders’ mean squared forecast errors). Thus, an efficient market aggregates traders’ heterogeneous information in an optimal way. Fourth, we prove that an efficient market produces a mean return (price) as a Blackwell sufficient (most informative) experiment among all possible aggregated expected return (price) forecasts.
Diphacinone and zinc phosphide toxicity in a flock of Peafowl.

Toxicity probably due to a combination of diphacinone and zinc phosphide was diagnosed in a flock of peafowl, in which 35 birds in a flock of 80 died over a span of 10 days without any apparent clinical signs. Chickens and guinea fowl, 30 each on the same premises, were not affected. Plastic tubes containing diphacinone and zinc phosphide were used on the premises to control ground squirrels. Most of the six dead peafowl, which ranged in age from 6 months to 4 years, had an accumulation of serosanguinous fluid in the abdominal cavity, semi-clotted blood over the liver lobes, increased pericardial fluid, and enlarged and pale kidneys. Pellets of diphacinone and zinc phosphide were found in the crop and gizzard contents from most of the birds. Microscopically, most of the birds had mild to moderate centrolobular degeneration of hepatocytes and multifocal degeneration of myofibres in the heart with infiltration by a few mononuclear cells. Acute nephrosis and mucosal oedema in the oesophagus and crop were als...