cssi/SciSciGPT-SciSciNet huggingface dataset:
Stellar Companions and the Age of HD 141569 and Its Circumstellar Disk

We investigate the stellar environment of the β Pictoris-like star HD 141569 with optical spectroscopy and near-infrared imaging. The B9.5 Ve primary and two other stars (types M2 and M4) both located in projection less than 9'' away have the same radial velocity and proper motion and therefore almost certainly form a triple star system. From their X-ray flux, lithium absorption, and location on pre-main-sequence evolutionary tracks, the companions appear to be 5 Myr old. HD 141569A is now one of the few main-sequence stars with a circumstellar disk that has a well-determined age. The circumstellar disk is composed of secondary debris material, thus placing an upper limit on the time needed for disk processing. These three stars may be part of an association of young stars.
Firefly Monte Carlo: exact MCMC with subsets of data

Markov chain Monte Carlo (MCMC) is a popular tool for Bayesian inference. However, MCMC cannot be practically applied to large data sets because of the prohibitive cost of evaluating every likelihood term at every iteration. Here we present Firefly Monte Carlo (FlyMC) MCMC algorithm with auxiliary variables that only queries the likelihoods of a subset of the data at each iteration yet simulates from the exact posterior distribution. FlyMC is compatible with modern MCMC algorithms, and only requires a lower bound on the per-datum likelihood factors. In experiments, we find that FlyMC generates samples from the posterior more than an order of magnitude faster than regular MCMC, allowing MCMC methods to tackle larger datasets than were previously considered feasible.
Spectral enrichments of model categories

We prove that every stable, presentable model category can be enriched in a natural way over symmetric spectra. As a consequence of the general theory, every object in such a model category has an associated homotopy endomorphism ring spectrum. Basic properties of these invariants are established.
Academic versus Non-Academic Emerging Adult College Student Technology Use.

Emerging adult college students have developmental and educational needs which are unique to their phase of life. Emerging adults are also increasingly identified by their technology use and practices. Collegiate instructors will be better equipped for educating these individuals when armed with insights concerning emerging adults’ technology related practices. The purpose of this study is to examine academic and non-academic technology use by emerging adult college students. Survey results (N = 235) provide insights into emerging adult college student technology preferences and frequency of use for academic and non-academic purposes. This study found that emerging adult college students have distinct technology preferences and practices relating to both academic and non-academic use, and prefer contextualization of technology accordingly.
Pollution and Mortality in the 19th Century

Mortality was extremely high in the industrial cities of the 19th century, but little is known about the role played by pollution in generating this pattern, due largely to a lack of direct pollution measures. I overcome this problem by combining data on the local composition of industries in Britain with information on the intensity with which industries used polluting inputs. Using this new measure, I show that pollution had a strong impact on mortality as far back as the 1850s. Industrial pollution explains 30-40% of the relationship between mortality and population density in 1851-60, and nearly 60% of this relationship in 1900. Growing industrial coal use from 1851-1900 reduced life expectancy by at least 0.57 years. A back-of-the envelope estimate suggests that the value of this loss of life, expressed as a one-time cost, was equal to at least 0.33-1.00 of annual GDP in 1900. Overall, these results show that industrial pollution was a major cause of mortality in the 19th century, particularly in urban areas, and that industrial growth during this period came at a substantial cost to health.
Estimating earthquake magnitudes from reported intensities in the central and eastern United States

A new macroseismic intensity prediction equation is derived for the central and eastern United States and is used to estimate the magnitudes of the 1811–1812 New Madrid, Missouri, and 1886 Charleston, South Carolina, earthquakes. This work improves upon previous derivations of intensity prediction equations by including additional intensity data, correcting magnitudes in the intensity datasets to moment magnitude, and accounting for the spatial and temporal population distributions. The new relation leads to moment magnitude estimates for the New Madrid earthquakes that are toward the lower range of previous studies. Depending on the intensity dataset to which the new macroseismic intensity prediction equation is applied, mean estimates for the 16 December 1811, 23 January 1812, and 7 February 1812 mainshocks, and 16 December 1811 dawn aftershock range from 6.9 to 7.1, 6.8 to 7.1, 7.3 to 7.6, and 6.3 to 6.5, respectively. One‐sigma uncertainties on any given estimate could be as high as 0.3–0.4 magnitude units. We also estimate a magnitude of 6.9±0.3 for the 1886 Charleston, South Carolina, earthquake. We find a greater range of magnitude estimates when also accounting for multiple macroseismic intensity prediction equations. The inability to accurately and precisely ascertain magnitude from intensities increases the uncertainty of the central United States earthquake hazard by nearly a factor of two. Relative to the 2008 national seismic hazard maps, our range of possible 1811–1812 New Madrid earthquake magnitudes increases the coefficient of variation of seismic hazard estimates for Memphis, Tennessee, by 35%–42% for ground motions expected to be exceeded with a 2% probability in 50 years and by 27%–35% for ground motions expected to be exceeded with a 10% probability in 50 years.
Applications of the Stell–Hemmer Potential to Understanding Second Critical Points in Real Systems

We consider the novel properties of the StellHemmer core-softened potentials. First we explore how the theoretically predicted second critical point for these potentials is related to the occurrence of the experimentally observed solidsolid isostructural critical point. We then discuss how this class of potentials can generate anomalies analogous to those found experimentally in liquid water.
Visible and Near-Infrared Photometry of the Centaur Objects 1995 GO and 5145 Pholus

Abstract We present visible and near-infrared broadband photometry of the Centaur objects 1995 GO and 5145 Pholus. Our data confirm the extremely redV−Jcolor and nearly solarJ−HandH−Kcolors of 5145 Pholus. OurV−Jdata reveal that 1995 GO is as red as the reddest D-type asteroid, 1748 Mauderli, but not nearly as red as 5145 Pholus. We suggest that the red color of 1995 GO is probably due to the presence of organic-rich materials produced by eons of particle bombardment and ultraviolet irradiation of surface grains, a process that may be widespread among the Centaur and trans-neptunian object populations. We show that theV−Jdata for the Centaurs suggest thatV−Jincreases with increasing semimajor axis. If this correlation is correct, then the red colors of the Centaurs 5145 Pholus and 1993 HA2may be typical of fairly pristine Centaur objects. In contrast, the progressively less red colors of 1995 GO and 2060 Chiron may be the result of an increased rate of resurfacing of these objects as they migrate progressively closer to the Sun.
Classical Topology and Quantum States

Any two infinite-dimensional (separable) Hilbert spaces are unitarily isomorphic. The sets of all their self-adjoint operators are also therefore unitarily equivalent. Thus if all self-adjoint operators can be observed, and if there is no further major axiom in quantum physics than those formulated for example in Dirac’s ‘quantum mechanics’, then a quantum physicist would not be able to tell a torus from a hole in the ground. We argue that there are indeed such axioms involving observables with smooth time evolution: they contain commutative subalgebras from which the spatial slice of spacetime with its topology (and with further refinements of the axiom, its C K - and C --structures) can be reconstructed using Gel’fand-Naimark theory and its extensions. Classical topology is an attribute of only certain quantum observables for these axioms, the spatial slice emergent from quantum physics getting progressively less differentiable with increasingly higher excitations of energy and eventually altogether ceasing to exist. After formulating these axioms, we apply them to show the possibility of topology change and to discuss quantized fuzzy topologies. Fundamental issues concerning the role of time in quantum physics are also addressed.
Efficient synthesis of tertiary amines from secondary amines

Reliable N-alkylations of secondary amines have been developed. By using DIAD and TPP (or PS-TPP) a variety of secondary amines can be converted to the corresponding tertiary amines in good to excellent yields with diverse alkylhalides; no formation of quaternary amine salts are observed. These protocols are amenable to combinatorial chemistry libraries, and are also useful for the syntheses of secondary amines by an acid lysis of the cleavable tertiary amino resins.
The propagation of rayleigh waves in heterogeneous media

A method is given for obtaining a power-series expansion in the wave-length for the Rayleigh wave-velocity in a half-space whose density ρ and elastic constants λ and μ, are functionsof depth. This is followed by a discussion of the Rayleigh wave-problem in media 1, 2, and 3, in which λ = μ and (ρ/ρ0) =(λ/λ0) = cos2βz, e2ρz, (1 + βz)2 , respectively. Starting with the value of for zero wave-length, the wave-velocity in medium 1 increases indefinitely with increasing wave-length and heterogeneity, while the wave-velocity in medium 2 approaches the finite limit of . The group-velocity in medium 1 goes through a minimum, then a maximum, from where it continuously diminishes with increasing wave-length. The group-velocity in medium 2 goes through a minimum and then rises asymptotically to the limiting value of the wavevelocity. In medium 3 both the wave-velocity and the group-velocity rise to the value at the critical wave-length. In all three media the wave-velocity is everywhere greater than the group-velocity. The ratio of the vertical to horizontal amplitudes at the surface decreases in all three media with increasing wave-length.
Duality and the fractional quantum Hall effect

Abstract The edge states of a sample displaying the quantum Hall effect (QHE) can be described by a (1+1)-dimensional (conformal) field theory of d massless scalar fields taking values on a d -dimensional torus. It is known from the work of Naculich, Frohlich et al. and others that the requirement of chirality of currents in this scalar field theory implies the Schwinger anomaly in the presence of an electric field, the anomaly coefficient being related in a specific way to Hall conductivity. The latter can take only certain restricted values with odd denominators if the theory admits fermionic states. We show that the duality symmetry under the O(d, d,; Z ) group of the free theory transforms the Hall conductivity in a well-defined way and relates integer and fractional QHE's. This means, in particular, that the edge spectra for dually related Hall conductivities are identical, a prediction which may be experimentally testable. We also show that Haldane's hierarchy as well as certain of Jain's fractions can be reproduced from the Laughlin fractions using the duality transformations. We thus find a framework for a unified description of the QHE's occurring at different fractions. We also give a simple derivation of the wave functions for fractions in Haldane's hierarchy.
Regio- and Stereoselective 1,2-Dihydropyridine Alkylation/Addition Sequence for the Synthesis of Piperidines with Quaternary Centers

The first example of C alkylation of 1,2-dihydropyridines with alkyl triflates and Michael acceptors was developed to introduce quaternary carbon centers with high regio- and diastereoselectivity. Hydride or carbon nucleophile addition to the resultant iminium ion also proceeded with high diastereoselectivity. Carbon nucleophile addition results in an unprecedented level of substitution to provide piperidine rings with adjacent tetrasubstituted carbon atoms.
Fine structure of parvocellular receptive fields in the primate fovea revealed by laser interferometry.

Optical blurring in the eye prevents conventional physiological techniques from revealing the fine structure of the small parvocellular receptive fields in the primate fovea in vivo. We explored the organization of receptive fields in macaque parvocellular lateral geniculate nucleus cells by using sinusoidal interference fringes formed directly on the retina to measure spatial frequency tuning at different orientations. Most parvocellular cells in and near the fovea respond reliably to spatial frequencies up to and beyond 100 cycles/° of visual angle, implying center input arising mainly from a single cone. Temporal frequency and contrast response characteristics were also measured at spatial frequencies up to 130 cycles/°. We compared our spatial frequency data with the frequency responses of model receptive fields that estimate the number, configuration, and weights of cones that feed the center and surround. On the basis of these comparisons, we infer possible underlying circuits. Most cells had irregular spatial frequency–response curves that imply center input from more than one cone. The measured responses are consistent with a single cone center together with weak input from nearby cones. By exposing a fine structure that cannot be discerned by conventional techniques, interferometry allows functional measurements of the early neural mechanisms in spatial vision.
Releasing multiply-imputed synthetic data generated in two stages to protect confidentiality

To protect the confidentiality of survey respondents' identities and sensi- tive attributes, statistical agencies can release data in which confidential values are replaced with multiple imputations. These are called synthetic data. We propose a two-stage approach to generating synthetic data that enables agencies to release different numbers of imputations for different variables. Generation in two stages can reduce computational burdens, decrease disclosure risk, and increase inferen- tial accuracy relative to generation in one stage. We present methods for obtaining inferences from such data. We describe the application of two stage synthesis to creating a public use file for a German business database.
International Expansion Strategy of Japanese Firms: Capability Building through Sequential Entry

This study examined the sequential entry process of Japanese electronic manufacturing firms into the United States during the period 1976–1989. The firms first entered their core businesses and tho...
Temperature dependent total scattering structural study of CaCu3Ti4O12

X-ray and neutron powder diffraction data as a function of temperature are analysed for the colossal dielectric constant material CaCu3Ti4O12. The local structure is studied using atomic pair distribution function analysis. No evidence is found for enlarged oxygen or Ti displacement parameters suggesting that short range octahedral tilt disorder and off-centre Ti displacements are minimal. However, an unusual temperature dependence for the atomic displacement parameters of calcium and copper is observed. Temperature dependent modelling of the structure, using bond valence concepts, suggests that the calcium atoms become underbonded below approximately 260 K, which provides a rationale for the unusually high Ca displacement parameters at low temperature.
The Zero Robotics SPHERES challenge 2010

The designation of the International Space Station as a National Laboratory enhances the ability to use the facility for educational objectives. The MIT Space Systems Laboratory and Aurora Flight Sciences started the Zero Robotics program to enable High School students to participate directly in the science conducted aboard the ISS. The program, based on the successful history of the FIRST Robotics Competition, opens development of SPHERES software algorithms to high school students. The team developed an IDE, simulation, and visualization engine for this purpose. The 2010 event took place from September to December. This event was considered a pilot because it was the first time the MIT SPHERES teams supported a nationwide event. The pilot included an application process, from which 24 schools from 19 states were selected. The teams participated in a simulation competition in October, which consisted of a full round-robin. In November the teams were split into three groups, and competed in double-elimination rounds using the MIT ground satellites. The top 10 teams from the two rounds participated in the ISS finals on December 16. The success of the 2010 event, which involved over 200 students, provides a promising future for the program.1, 2
The Puzzling Divergence of Rents and User Costs, 1980-2004

This paper demonstrates that, in the context of U.S. housing data, rents and ex ante user costs diverge markedly—in both growth rates and levels—for extended periods of time, a seeming failure of arbitrage and a puzzle from the perspective of standard capital theory. The tremendous volatility of even appropriately-smoothed ex ante annual user cost measures implies that such measures are unsuitable for inclusion in official price statistics. The divergence holds not only at the aggregate level, but at the metropolitan-market level as well, and is robust across different house price and rent measures. But transactions costs matter: the large persistent divergences did not imply the presence of unexploited profit opportunities. In particular, even though detached housing is readily moved between owner and renter markets, and the detached-unit rental market is surprisingly thick, transactions costs would have prevented risk-neutral investors from earning expected profits by buying a property to rent out for a year, and would have prevented risk-neutral homeowners from earning expected profits by selling their homes and becoming renters for a year. Finally, computing implied appreciation as a residual yields a house price forecast with huge errors; but either longer-horizon or no-real-capital-gains forecasts—which turn out to have similar forecast errors—imply a far less divergent user cost measure which might ultimately be useful for official price statistics. Some conjectures are offered.
Locating the LCROSS Impact Craters

The Lunar CRater Observations and Sensing Satellite (LCROSS) mission im- pacted a spent Centaur rocket stage into a permanently shadowed region near the lunar south pole. The Sheperding Spacecraft (SSC) separated ∼9 hours before impact and performed a small braking maneuver in order to observe the Centaur impact plume, looking for evidence of water and other volatiles, before impacting itself. This paper describes the registration of imagery of the LCROSS impact region from the mid- and near-infrared cameras onboard the SSC, as well as from the Goldstone radar. We compare the Centaur impact features, positively identified in the first two, and with a con- sistent feature in the third, which are interpreted as a 20 m diameter crater surrounded by a 160 m diameter ejecta region. The images are registered to Lunar Reconnaisance Orbiter (LRO) topographical data which allows determination of the impact location. This location is compared with the impact location derived from ground-based tracking and propagation of the spacecraft's trajectory and with locations derived from two hybrid imagery/trajectory methods. The four methods give a weighted average Centaur impact location of −84.6796°, −48.7093°, with a 1σ uncertainty of 115 m along latitude, and 44 m along longitude, just 146 m from the target impact site. Meanwhile, the trajectory-derived SSC impact location is −84.719°, −49.61°, with a 1σ uncertainty of 3 m along the Earth vector and 75 m or- thogonal to that, 766 m from the target location and 2.803 km south-west of the Centaur impact. We also detail the Centaur impact angle and SSC instrument pointing errors. Six high- level LCROSS mission requirements are shown to be met by wide margins. We hope that
Social Norms and Energy Conservation

article i nfo This paper evaluates a series of programs run by a company called OPOWER to send Home Energy Report letters to residential utility customers comparing their electricity use to that of their neighbors. Using data from randomized natural field experiments at 600,000 treatment and control households across the United States, I estimate that the average program reduces energy consumption by 2.0%. The program provides additional evidence that non-price interventions can substantially and cost effectively change consumer behavior: the effect is equivalent to that of a short-run electricity price increase of 11 to 20%, and the cost effectiveness compares favorably to that of traditional energy conservation programs. Perhaps because the treatment included descriptive social norms, effects are heterogeneous: households in the highest decile of pre-treatment consumption decrease usage by 6.3%, while consumption by the lowest decile decreases by only 0.3%. A regression discontinuity design shows that different categories of "injunctive norms" played an insignificant role in encouraging relatively low users not to increase usage.
Nonparametric One-Bit Quantizers for Distributed Estimation

In this paper, we consider the nonparametric distributed parameter estimation problem using one-bit quantized data from peripheral sensors. Assuming that the sensor observations are bounded, nonparametric distributed estimators are proposed based on the knowledge of the first N moments of sensor noises. These estimators are shown to be either unbiased or asymptotically unbiased with bounded and known estimation variance. Further, the uniformly optimal quantizer based only on the first moment information and the optimal minimax quantizer with the knowledge of the first two moments are determined. The proposed estimators are shown to be consistent even when local sensor noises are not independent but m-dependent. The relationship between the proposed approaches and dithering in quantization is also investigated. The superiority of the proposed quantization/estimation schemes is illustrated via illustrative examples.
Fire retardancy of clay/carbon nanofiber hybrid sheet in fiber reinforced polymer composites

In this paper, two kinds of clay/carbon nanofiber hybrid sheets containing 0.05 wt% and 0.20 wt% of Cloisite Na + clay, were fabricated through a high-pressure filtration system. These sheets were integrated onto the surface of laminated composites like traditional continuous fiber mats through vacuum-assisted resin transfer molding process. The fire performance of the laminated composites was evaluated with cone calorimeter tests under an external radiant heat flux of 50 kW/m 2 . Their residues were analyzed with scanning electron microscopy and thermal gravimetric analyses. It was found that the clay/nanofiber hybrid sheets survived on the combustion surface of composites and significantly reduced the heat release rate by � 60.5%. The protective clay layer reduces the heat release rates and the nanofiber network reinforces the clay layer against the air bubbling and melt flow of the products degraded from the polymer resin. The clay/carbon nanofiber hybrid sheet combines the barrier and insulator effects of the clays with the re-emitting heat effect of carbon nanofibers on the combustion surface of composites. Published by Elsevier Ltd.
Globally and locally minimal weight spanning tree networks

Abstract The competition between local and global driving forces is significant in a wide variety of naturally occurring branched networks. We have investigated the impact of a global minimization criterion versus a local one on the structure of spanning trees. To do so, we consider two spanning tree structures—the generalized minimal spanning tree (GMST) defined by Dror et al. (Eur. J. Oper. Res. 120 (2000) 583) and an analogous structure based on the invasion percolation network, which we term the generalized invasive spanning tree (GIST). In general, these two structures represent extremes of global and local optimality, respectively. Structural characteristics are compared between the GMST and GIST for a fixed lattice. In addition, we demonstrate a method for creating a series of structures which enable one to span the range between these two extremes. Two structural characterizations, the occupied edge density (i.e., the fraction of edges in the graph that are included in the tree) and the tortuosity of the arcs in the trees, are shown to correlate well with the degree to which an intermediate structure resembles the GMST or GIST. Both characterizations are straightforward to determine from an image and are potentially useful tools in the analysis of the formation of network structures.
Copper/Palladium Synergistic Catalysis for the syn- and anti-Selective Carboboration of Alkenes

A method for the diastereoselective carboboration of 1,2-disubstituted styrenes with aryl/vinyl bromides and (Bpin)2 is reported. High diastereoselectivities and yields are observed for the formation of either diastereomer of the product from a single alkene isomer. These reactions provide access to a diverse range of structures from simple starting materials.
Central limit theorem for first-passage percolation time across thin cylinders

We prove that first-passage percolation times across thin cylinders of the form [0, n] × [−hn, hn]d-1 obey Gaussian central limit theorems as long as hn grows slower than n1/(d+1). It is an open question as to what is the fastest that hn can grow so that a Gaussian CLT still holds. Under the natural but unproven assumption about existence of fluctuation and transversal exponents, and strict convexity of the limiting shape in the direction of (1, 0, . . . , 0), we prove that in dimensions 2 and 3 the CLT holds all the way up to the height of the unrestricted geodesic. We also provide some numerical evidence in support of the conjecture in dimension 2.
MID-INFRARED EXTINCTION MAPPING OF INFRARED DARK CLOUDS: PROBING THE INITIAL CONDITIONS FOR MASSIVE STARS AND STAR CLUSTERS

Infrared dark clouds (IRDCs) are cold, dense regions of giant molecular clouds that are opaque at wavelengths ~10 μm or more and thus appear dark against the diffuse Galactic background emission. They are thought to be the progenitors of massive stars and star clusters. We use 8 μm imaging data from Spitzer Galactic Legacy Mid-Plane Survey Extraordinaire to make extinction maps of 10 IRDCs, selected to be relatively nearby and massive. The extinction mapping technique requires construction of a model of the Galactic IR background intensity behind the cloud, which is achieved by correcting for foreground emission and then interpolating from the surrounding regions. The correction for foreground emission can be quite large, up to ~50% for clouds at ~5 kpc distance, thus restricting the utility of this technique to relatively nearby clouds. We investigate three methods for the interpolation, finding systematic differences at about the 10% level, which, for fiducial dust models, corresponds to a mass surface density Σ = 0.013 g cm-2, above which we conclude that this extinction mapping technique attains validity. We examine the probability distribution function of Σ in IRDCs. From a qualitative comparison with numerical simulations of astrophysical turbulence, many clouds appear to have relatively narrow distributions suggesting relatively low (less than five) Mach numbers and/or dynamically strong magnetic fields. Given cloud kinematic distances, we derive cloud masses. Rathborne, Jackson, and Simon identified cores within the clouds and measured their masses via millimeter dust emission. For 43 cores, we compare these mass estimates with those derived from our extinction mapping, finding good agreement: typically factors of 2 difference for individual cores and an average systematic offset of 10% for the adopted fiducial assumptions of each method. We find tentative evidence for a systematic variation of these mass ratios as a function of core density, which is consistent with models of ice mantle formation on dust grains and subsequent grain growth by coagulation, and/or with a temperature decrease in the densest cores.
Neutralino, axion and axino cold dark matter in minimal, hypercharged and gaugino AMSB

Supersymmetric models based on anomaly-mediated SUSY breaking (AMSB) generally give rise to a neutral wino as a WIMP cold dark matter (CDM) candidate, whose thermal abundance is well below measured values. Here, we investigate four scenarios to reconcile AMSB dark matter with the measured abundance: 1. non-thermal wino production due to decays of scalar fields (e.g. moduli), 2. non-thermal wino production due to decays of gravitinos, 3. non-thermal wino production due to heavy axino decays, and 4. the case of an axino LSP, where the bulk of CDM is made up of axions and thermally produced axinos. In cases 1 and 2, we expect wino CDM to constitute the entire measured DM abundance, and we investigate wino-like WIMP direct and indirect detection rates. Wino direct detection rates can be large, and more importantly, are bounded from below, so that ton-scale noble liquid detectors should access all of parameter space for m1500 GeV. Indirect wino detection rates via neutrino telescopes and space-based cosmic ray detectors can also be large. In case 3, the DM would consist of an axion plus wino admixture, whose exact proportions are very model dependent. In this case, it is possible that both an axion and a wino-like WIMP could be detected experimentally. In case 4., we calculate the re-heat temperature of the universe after inflation. In this case, no direct or indirect WIMP signals should be seen, although direct detection of relic axions may be possible. For each DM scenario, we show results for the minimal AMSB model, as well as for the hypercharged and gaugino AMSB models.
Rhodium Dinaphthocyclooctatetraene Complexes: Synthesis, Characterization and Catalytic Activity in [5+2] Cycloadditions

Rh COT in the act: a Ni(0)-catalyzed [2+2+2+2] cycloaddition provides a high-yielding, scalable synthesis of the ligand dinaphtho[a,e]cyclooctatetraene (dnCOT). dnCOT complexation with Rh(I) gives [Rh(dnCOT)(MeCN)(2)]SbF(6), an excellent catalyst for [5+2] cycloadditions of vinylcyclopropanes and π-systems with impressive functional group compatibility.
Annual survey of organometallic metal cluster chemistry for the year 1995

Abstract The synthetic, mechanistic, and structural chemistry of organometallic metal cluster compounds is reviewed for the year 1995.
First Results from Lattice Simulation of the PWMM

We present results of lattice simulations of the Plane Wave Matrix Model (PWMM). The PWMM is a theory of supersymmetric quantum mechanics that has a well-defined canonical ensemble. We simulate this theory by applying rational hybrid Monte Carlo techniques to a naive lattice action. We examine the strong coupling behaviour of the model focussing on the deconfinement transition.
Managers' Implicit Assumptions About Personnel

Effective managers recognize both positive and negative changes in employee performance and take appropriate remedial action when required. Managers' assumptions about the rigidity or malleability of personal attributes (e.g., ability and personality) affect their performance of these critical personnel management tasks. To the extent that managers assume that personal attributes are fixed traits that are largely stable over time, they tend to inadequately recognize actual changes in employee performance and are disinclined to coach employees regarding how to improve their performance. However, a growth-mindset intervention can lead managers to relinquish their fixed mindset and subsequently provide more accurate performance appraisals and helpful employee coaching. Implications for performance evaluation procedures and avenues for future research are outlined.
Randomness and sparsity induced codebook learning with application to cancer image classification

Codebook learning is one of the central research topics in computer vision and machine learning. In this paper, we propose a new codebook learning algorithm, Randomized Forest Sparse Coding (RFSC), by harvesting the following three concepts: (1) ensemble learning, (2) divide-and-conquer, and (3) sparse coding. Given a set of training data, a randomized tree can be used to perform data partition (divide-and-conquer); after a tree is built, a number of bases are learned from the data within each leaf node for a sparse representation (subspace learning via sparse coding); multiple trees with diversities are trained (ensemble), and the collection of bases of these trees constitute the codebook. These three concepts in our codebook learning algorithm have the same target but with different emphasis: subspace learning via sparse coding makes a compact representation, and reduces the information loss; the divide-and-conquer process efficiently obtains the local data clusters; an ensemble of diverse trees provides additional robustness. We have conducted classification experiments on cancer images as well as a variety of natural image datasets and the experiment results demonstrate the efficiency and effectiveness of the proposed method.
Parametric adaptive signal detection for hyperspectral imaging

Hyperspectral imaging (HSI) sensors can provide very fine spectral resolution that allows remote identification of ground objects smaller than a full pixel in an HSI image. Traditional approaches to the so-called subpixel target signal detection problem are training inefficient due to the need for an estimate of a large-size covariance matrix of the background from target-free training pixels. This imposes a training requirement that is often difficult to meet in a heterogeneous environment. In this paper, a class of training-efficient adaptive signal detectors is presented by exploiting a parametric model that takes into account the nonstationarity of HSI data in the spectral dimension. A maximum-likelihood (ML) estimator is developed to estimate the parameters associated with the proposed parametric model. Several important issues are discussed, including model order selection, training screening, and time-series-based whitening and detection, which are intrinsic parts of the proposed parametric adaptive detectors. Experimental results using real HSI data reveal that the proposed parametric detectors are more training efficient and outperform conventional covariance-matrix-based detectors when the training size is limited
Physical limits to biochemical signaling

Many crucial biological processes operate with surprisingly small numbers of molecules, and there is renewed interest in analyzing the impact of noise associated with these small numbers. Twenty-five years ago, Berg and Purcell showed that bacterial chemotaxis, where a single-celled organism must respond to small changes in concentration of chemicals outside the cell, is limited directly by molecule counting noise and that aspects of the bacteria's behavioral and computational strategies must be chosen to minimize the effects of this noise. Here, we revisit and generalize their arguments to estimate the physical limits to signaling processes within the cell and argue that recent experiments are consistent with performance approaching these limits.
Organocatalytic asymmetric aza-Nazarov cyclization of an azirine

An unusual organocatalytic asymmetric cyclization of a ketoazirine that is accompanied by a kinetic resolution leads to 4-hydroxy-3-oxo-1,2,3,6-tetrahydropyridine-2-carboxylates in >99/1 er.
Limits in Compact Abelian Groups

Abstract For X a compact Abelian group and B an infinite subset of its dual X ˆ , let C B be the set of all x ∈ X such that 〈 φ ( x ) : φ ∈ B 〉 converges to 1. If F is a free filter on X ˆ , let D F = ⋃ { C B : B ∈ F } . The sets C B and D F are subgroups of X. C B always has Haar measure 0, while the measure of D F depends on F . We show that there is a filter F such that D F has measure 0 but is not contained in any C B . This generalizes previous results for the special case where X is the circle group.
Total Synthesis of (−)- and ent-(+)-Vindoline

Two exceptionally concise total syntheses of (−)- and ent-(+)-vindoline are detailed enlisting a diastereoselective tandem [4 + 2]/[3 + 2] cycloaddition of a 1,3,4-oxadiazole. The unique reaction cascade assembles the fully functionalized pentacyclic ring system of vindoline in a single step that forms four C−C bonds and three rings while introducing all requisite functionality and setting all six stereocenters within the central ring including three contiguous and four total quaternary centers.
Allene ether Nazarov cyclization

The ease of synthesis and the exceptional reactivity of alkoxyallenes has led to their use in a large number of highly diverse applications. This Report describes their use in various versions of the allene ether Nazarov cyclization. Following a brief introduction to the Nazarov cyclization (Section 1), the oxidative cyclization of vinyl alkoxyallenes is discussed first (Section 2). Nazarov cyclizations of α-alkoxyallenyl vinyl ketones and of α-alkoxyallenyl vinyl tertiary carbinols are covered (Section 3). The discovery and the subsequent rational design of acetals that serve as chiral auxiliaries on the allene in highly enantioselective Nazarov cyclizations is explained (Section 4). Interrupted Nazarov cyclizations of alkoxyallenes that are generated in situ from the isomerization of propargyl ethers on solid supports are discussed, including the evolution of a highly diastereoselective, chiral auxiliary controlled version of the reaction. Some applications of the methodology to natural products total synthesis have been included so as to provide the reader with benchmarks with which to judge the utility of the methodology.
Vane Clocking Effects on Stall Margin in a Multistage Compressor

Vane clocking is the circumferential indexing of adjacent vane rows with similar vane counts. There are no reports in the open literature regarding clocking effects on stall margin. Recent vane clocking investigations showed a measurable impact on embedded stage efficiency in a three-stage axial compressor research facility. The current work aims to determine the change in stall margin with vane clocking in this multistage compressor facility. Six clocking configurations were investigated, and the onset of stall was measured using unsteady pressure transducers flush-mounted in the casing at the leading edge of each rotor row. Data were acquired while clocking the embedded stage, the stage with measurable efficiency changes associated with vane clocking. Data were also acquired while clocking the first stage, the stalling stage. The changes in stall margin for different clocking configurations for this compressor were small and within the measurement uncertainty, although a weak sinusoidal trend was presen...
Basic concepts for planning an electronic data processing system

The achievement of a reliable management information feedback system is dependent upon meaningful and well-defined electronic data processing objectives and basic concepts. The purpose of this paper is to attempt to define those basic concepts which can be used as a foundation for planning advanced electronic data processing (EDP) systems.
Voting Technology, Vote-by-Mail, and Residual Votes in California, 1990–2010

We examine how the growth in vote-by-mail and changes in voting technologies led to changes in the residual vote rate in California from 1990 to 2010. In California’s presidential elections, counties that abandoned punch cards in favor of optical scanning enjoyed a significant improvement in the residual vote rate. We also conduct the first analysis of the effects of the rise of vote-by-mail on residual votes. Regardless of the election, increased use of the mail to cast ballots is robustly associated with a significant rise in the residual vote rate.
Asymptotic enumeration of permutations avoiding generalized patterns

Motivated by the recent proof of the Stanley-Wilf conjecture, we study the asymptotic behavior of the number of permutations avoiding a generalized pattern. Generalized patterns allow the requirement that some pairs of letters must be adjacent in an occurrence of the pattern in the permutation, and consecutive patterns are a particular case of them. We determine the asymptotic behavior of the number of permutations avoiding a consecutive pattern, showing that they are an exponentially small proportion of the total number of permutations. For some other generalized patterns we give partial results, showing that the number of permutations avoiding them grows faster than for classical patterns but more slowly than for consecutive patterns.
Tensor product multiplicities, canonical bases and totally positive varieties

We obtain a family of explicit "polyhedral" combinatorial expressions for multiplicities in the tensor product of two simple finite-dimensional modules over a complex semisimple Lie algebra. Here "polyhedral" means that the multiplicity in question is expressed as the number of lattice points in some convex polytope. Our answers use a new combinatorial concept of $\ii$-trails which resemble Littelmann's paths but seem to be more tractable. We also study combinatorial structure of Lusztig's canonical bases or, equivalently of Kashiwara's global bases. Although Lusztig's and Kashiwara's approaches were shown by Lusztig to be equivalent to each other, they lead to different combinatorial parametrizations of the canonical bases. One of our main results is an explicit description of the relationship between these parametrizations. Our approach to the above problems is based on a remarkable observation by G. Lusztig that combinatorics of the canonical basis is closely related to geometry of the totally positive varieties. We formulate this relationship in terms of two mutually inverse transformations: "tropicalization" and "geometric lifting."
Simulations of nanowire transistors: atomistic vs. effective mass models

The ballistic performance of electron transport in nanowire transistors is examined using a 10 orbital sp3d5s* atomistic tight-binding model for the description of the electronic structure, and the top-of-the-barrier semiclassical ballistic model for calculation of the transport properties of the transistors. The dispersion is self consistently computed with a 2D Poisson solution for the electrostatic potential in the cross section of the wire. The effective mass of the nanowire changes significantly from the bulk value under strong quantization, and effects such as valley splitting strongly lift the degeneracies of the valleys. These effects are pronounced even further under filling of the lattice with charge. The effective mass approximation is in good agreement with the tight binding model in terms of current–voltage characteristics only in certain cases. In general, for small diameter wires, the effective mass approximation fails.
Testability Emphasis in the General Electric A/VLSI Program

General Electric's Aerospace Business Group has initiated an extensive Advanced Very Large Scale Integration Program to generate the technology needed to produce 1.25-micron integrated circuits that will substantially improve its military products. This article emphasizes practical real-world experiences encountered in designing for testability. It discusses test-oriented macrocells, design rules, software checks, testability design guidelines, test specification language, and workstation communication with automated test equipment.
The theory of ordinal length

Gulliksen, following Bass’s observations, extended the notion of length to an ordinal-valued invariant defined on the class of finitely generated modules over a Noetherian ring. We show how to calculate this combinatorial invariant by means of the fundamental cycle of the module, thus linking the lattice of submodules to homological properties of the module. Using this, we equip each module with its canonical topology. From ordinal length, other ordinal-valued invariants can be derived, such as filtration rank.
High-temperature synthesis of Rb2MnP2S6 in molten salt medium.

Transparent yellow plates of rubidium manganese hexa­thio­diphosphate, Rb2MnP2S6, were synthesized in molten RbBr. The compound is isotypic to other compounds of the type A2MP2Q6 (A = K, Rb, Cs; M = Mn, Fe; Q = S, Se). Its structure can be viewed as columns of face-sharing S6 polyhedra parallel to the a axis, interconnected by Rb+. The S6 polyhedra are centered alternately by Mn (in octahedral coordination) and P2 units (in trigonal antiprisms). The Mn atom and P2S6 group lie on centers of symmetry.
The BRAIN Initiative: developing technology to catalyse neuroscience discovery

The evolution of the field of neuroscience has been propelled by the advent of novel technological capabilities, and the pace at which these capabilities are being developed has accelerated dramatically in the past decade. Capitalizing on this momentum, the United States launched the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative to develop and apply new tools and technologies for revolutionizing our understanding of the brain. In this article, we review the scientific vision for this initiative set forth by the National Institutes of Health and discuss its implications for the future of neuroscience research. Particular emphasis is given to its potential impact on the mapping and study of neural circuits, and how this knowledge will transform our understanding of the complexity of the human brain and its diverse array of behaviours, perceptions, thoughts and emotions.
Bioorganometallic Chemistry with IspG and IspH: Structure, Function, and Inhibition of the [Fe4S4] Proteins Involved in Isoprenoid Biosynthesis

Enzymes of the methylerythritol phosphate pathway of isoprenoid biosynthesis are attractive anti-infective drug targets. The last two enzymes of this pathway, IspG and IspH, are [Fe4 S4 ] proteins that are not produced by humans and catalyze 2 H(+) / 2 e(-) reductions with novel mechanisms. In this Review, we summarize recent advances in structural, mechanistic, and inhibitory studies of these two enzymes. In particular, mechanistic proposals involving bioorganometallic intermediates are presented, and compared with other mechanistic possibilities. In addition, inhibitors based on substrate analogues as well as developed by rational design and compound-library screening, are discussed. The results presented support bioorganometallic catalytic mechanisms for IspG and IspH, and open up new routes to anti-infective drug design targeting [Fe4 S4 ] clusters in proteins.
Strongly correlated multilayered nanostructures near the Mott transition

We examine devices constructed out of multilayered sandwiches of semi-infinite metal-barrier-semi-infinite metal, with the barrier tuned to lie near the quantum critical point of the Mott metal-insulator transition. By employing dynamical mean field theory, we are able to solve the many-body problem exactly (within the local approximation) and determine the density of states through the nanostructure and the charge transport perpendicular to the planes. We introduce a generalization of the Thouless energy that describes the crossover from tunneling to incoherent thermally activated transport.
An efficient synthesis of (−)-3-deazaaristeromycin

Abstract The coupling reaction of 4-chloro-1 H -imidazo[4,5- c ]pyridine (6-chloro-3-deazapurine) and (3a S ,4 S ,6 R ,6a R )-tetrahydro-2,2-dimethyl-6-vinyl-3a H -cyclopenta-[ d ][1,3]dioxo-4-ol under Mitsunobu reaction conditions provides, after three subsequent straightforward reactions, ready access to the highly biologically active (−)-3-deazaaristeromycin. The versatility of this procedure opens access to a diverse pool of 3-deazapurine carbocyclic nucleosides.