cssi/SciSciGPT-SciSciNet huggingface dataset:
Diastereoselective and Enantioselective Rh(I)-Catalyzed Additions of Arylboronic Acids to N-tert-Butanesulfinyl and N-Diphenylphosphinoyl Aldimines

Two new Rh(I)-catalyzed methods for the synthesis of chiral α-branched amines via addition of arylboronic acids to N-tert-butanesulfinyl and N-diphenylphosphinoyl imines have been developed. The syntheses are more functional group tolerant than alternative methods utilizing Grignard or organolithium reagents, and the imine activating groups used are easily removed. These methods are both high-yielding (70−97% yield) and very selective (>93:7 dr and 88−94% ee). Significantly, the N-tert-butanesulfinyl imine method works for aliphatic imines with enolizable protons. In addition, a one-pot procedure for the synthesis of N-tert-butanesulfinyl protected α-branched amines from aldehydes has been developed.
Indirect Cross-Validation for Density Estimation

A new method of bandwidth selection for kernel density estimators is proposed. The method, termed indirect cross-validation (ICV), makes use of so-called selection kernels. Least-squares cross-validation (LSCV) is used to select the bandwidth of a selection-kernel estimator and this bandwidth is appropriately rescaled for use in a Gaussian kernel estimator. The proposed selection kernels are linear combinations of two Gaussian kernels and need not be unimodal or positive. A theory is developed showing that the relative error of ICV bandwidths can converge to 0 at a rate of n−1/4, which is substantially better than the n−1/10 rate of LSCV. Interestingly, the selection kernels that are best for purposes of bandwidth selection are very poor if used to actually estimate the density function. This property appears to be part of the larger and well-documented paradox to the effect that “the harder the estimation problem, the better cross-validation performs.” The ICV method uniformly outperforms LSCV in a simul...
Universe as quantum computer

This paper shows that universal quantum computers possess decoherent histories in which complex adaptive systems evolve with high probability.
Hierarchical Zoning, Incompatible Uses and Price Discounts

This study examines an aspect of hierarchical zoning. Hierarchical zoning, unlike mutually exclusive zoning, is uni-directional in that it protects upper-level residential uses from nonconforming, non-residential uses but not vice versa. The result is that the lower-level zones can be a mixture of several nonconforming, incompatible uses. This unique attribute of hierarchical zoning offers a window of opportunity for choices for affordable housing at affordable locations. Using hedonic analysis, empirical evidence shows that huge price discounts (over 15%) are associated with apartments that are situated in nonconforming zones. Arguments here support more flexible zoning.
Seismic evidence for accumulated oceanic crust above the 660‐km discontinuity beneath southern Africa

[1] High-pressure assemblages of subducted oceanic crust are denser than the normal upper mantle but less dense than the uppermost lower mantle. Thus subducted oceanic crust may accumulate at the base of the upper mantle. Direct observational evidence for this hypothesis, however, remains elusive. We present an analysis of a negative-polarity shear wave converted from compressional wave at a seismic discontinuity near 570--600 km depth beneath southern Africa. The negative polarity of the converted phase indicates a ∼2.2 ± 0.2% S-velocity decrease with depth at the seismic discontinuity. This velocity reduction is associated, however, with a low velocity contrast at the 660-km discontinuity. The exsolution of Ca-perovskite in former oceanic crust at depth greater than 600 km and the associated small volume fraction of ringwoodite are plausible explanations for the apparent paradox between the negative velocity discontinuity and the low velocity contrast at the 660-km discontinuity.
Fundamental design problems and properties of microwave plasma/ion sources

Design problems and procedures associated with microwave plasma sources are applied to cylindrical plasmas inside coaxial and cylindrical cavities. The experimental performance of these cavities is presented. Measurements of electron density and electron temperature for several inert gases, and different tube diameters and pressures are presented and compared with microwave and positive column discharge theories. Results show that plasmas with electron densities in excess of 10 to the 12th/cu cm are easily produced from microwave S band energy. The potential for these sources for ion engines is evaluated.
Telencephalic distribution of terminals of brainstem norepinephrine neurons

Publisher Summary This chapter describes the telencephalic distribution of terminals of brainstem norepinephrine (NE) neurons. The auditory cortex of the cat was isolated from subcortical, and other cortical areas with its blood supply intact, and subsequently analyzed for norepinephrine content, and the capacity to produce norepinephrine from intravenously administered, labeled tyrosine. It is found that if norepinephrine-producing neurons are present, both cell bodies and axons, in cortex, they should be preserved after isolation of the cortex, and should continue to have the capacity to produce norepinephrine. In isolated cat auditory cortex, however, there is no assayable norepinephrine present, and none is produced from labeled tyrosine even though the tyrosine enters cortex. The greater tyrosine content of denervated cortex probably reflects the loss of white matter in these samples. In the second study, the effect of restricted unilateral lesions in the locus coeruleus on telencephalic, and diencephalic amines was analyzed. Localized locus coeruleus destruction produces a nearly total unilateral depletion of telencephalic norepinephrine without significantly affecting thalamic or hypothalamic norepinephrine levels.
Neurath's programme for naturalistic epistemology

Abstract I examine the thesis that Otto Neurath anticipated the programme of naturalised epistemology already at the time of the Vienna Circle and consider the relation between Neurath's proposals and those of two contemporary theorists whose research programmes he would thus have broadly anticipated. The thesis is confirmed by reference to Neurath's own writings. The connection between Neurath's programme and the programmes of his two successors considered here, however, is found to be highly indirect in one case and nonexistent in the other — despite their undeniable overlap.
Institutional Monitoring and REIT CEO Compensation

Our objective in this paper is to investigate the relationship between institutional ownership and CEO compensation structure of REITs. Based on detailed analyses of data on institutional ownership, performance, CEO and board characteristics over the 10 year period 1998–2007, we find significant evidence that large institutions influence governance through CEO compensation—greater institutional ownership is associated with greater emphasis on incentive-based compensation (higher pay-performance sensitivity of CEO compensation), and higher cash and total compensation for CEOs. Further, we find that institutions are less active when managers are performing in a superior fashion. Two important conclusions emerge from the analysis. First, similar to unregulated firms, institutional owners do act as monitors in REITs. Broadly, this result suggests that governance is necessary for REITs. Second, institutional investors set a high pay-performance sensitivity for CEOs, but are willing to pay higher cash compensation to induce managers to take risk.
A Crack in the Conformal Window

In N = 2 superconformal three-dimensional eld theory the R-symmetry is determined by locally maximizing the free energy F on the three-sphere. Using F - maximization, we study the N = 2 supersymmetric U(Nc) gauge theory coupled to Nf pairs of fundamental and anti-fundamental superelds in the Veneziano large Nc limit, of the theory for x < xc allows us to determine the R-charges and F for 1 x < xc. Adding a Chern-Simons term removes the transition at xc. In these more general theories we study the scaling dimensions of meson operators as functions of x and =jkj=Nc. We nd that there is an interesting transition in behavior at = 1.
Vibrational analysis of 1,2-dichloro-2-methylpropane and 1,2-dibromo-2-methylpropane

Abstract Liquid-state IR and Raman spectra and solid-state IR spectra have been obtained for 1,2-dichloro-2-methylpropane and l,2-dibromo-2-methylpropane. Carbon-halogen stretching bands are observed in the liquid-state spectrum of the dichloro compound at 751, 725, 624 and 574 cm −1 and at 677, 640, 551 and 507 cm −1 in the liquid-state spectrum of the dibromo compound. Both compounds exist as P C Tt HHH and P X T XHH conformations in the liquid, but only the P X T XHH conformer is present for each in the crystalline solid. Further Interpretation of the spectra was aided by normal coordinate calculations.
Au-catalyzed synthesis of 2-alkylindoles from N-arylhydroxylamines and terminal alkynes

The first gold-catalyzed addition of N-arylhydroxylamines to aliphatic terminal alkynes is developed to access O-alkenyl-N-arylhydroxylamines, which undergo facile in situ sequential 3,3-rearrangements and cyclodehydrations to afford 2-alkylindoles with regiospecificity and under exceptionally mild reaction conditions.
Astronomical spectrograph calibration with broad-spectrum frequency combs

Broadband femtosecond-laser frequency combs are filtered to spectrographically resolvable frequency-mode spacing, and limitations of using cavities for spectral filtering are considered. Data and theory are used to show implications relevant to spectrographic calibration of high-resolution, astronomical spectrometers.
Concept for a large scalable space telescope: in-space assembly

We present a conceptual design for a scalable (10-50 meter segmented filled-aperture) space observatory operating at UV-optical-near infrared wavelengths. This telescope is designed for assembly in space by robots, astronauts or a combination of the two, as envisioned in NASA's Vision for Space Exploration. Our operations concept for this space telescope provides for assembly and check-out in an Earth Moon L2 (EML2) orbit, and transport to a Sun-Earth L2 (SEL2) orbit for science operations and routine servicing, with return to EML2 for major servicing. We have developed and analyzed initial designs for the optical, structural, thermal and attitude control systems for a 30-m aperture space telescope. We further describe how the separate components are packaged for launch by heavy lift vehicle(s) and the approach for the robot assembly of the telescope from these components.
Detection of a white dwarf in a visual binary system

The F6 giant HD 160365 was detected to have a white dwarf companion about 8 arcsec south of the star. The UV energy distribution observed with International Ultraviolet Explorer (IUE) shows that the white dwarf has an effective temperature of 23,000 +/- 2,000 K. If log g = 8 the Ly(alpha) profile indicates an effective temperature around 24,500 K. Using the theoretical models, one finds a visual magnitude of m(sub v) is approximately 16.5. For T(sub eff) = 24,500 K one expects for a white dwarf a luminosity of log L/solar luminosity is approximately -1.3 and M(sub V) is approximately 10.67. This gives a distance modulus for the system of m(sub v) - M(sub V) = 5.83 and an absolute magnitude M(sub v) = 0.3 for the giant.
Interferometric correlogram-space analysis

Controlled-source seismic interferometry is a method of obtaining a virtual shot gather from a collection of physical shot gathers. The set of traces corresponding to two common receiver gathers from many physical shots is used to synthesize a virtual shot located at one of the receivers and a receiver at the other. An estimate of the Green's function between these two receivers is obtained by first crosscorrelating corresponding pairs of traces from each of the shots and then stacking the resulting crosscorrelograms. We studied the structure of crosscorrelograms obtained from a VSP acquisition geometry using surface sources and downhole receivers. The model is purely acoustic and contains flat or dipping layers and/or point inclusions that act as diffractors. We propose a semblance analysis based on moveout curves for both point diffractors and flat or dipping layers, which can be used to improve the quality of redatumed traces either by rejecting certain events prior to stacking or by enhancing them.
Enthalpies of combustion of D-ribose and 2-deoxy-D-ribose

Abstract The enthalpies of combustion of the crystalline monosaccharides d -ribose (C5H10O5, cr) and 2-deoxy- d -ribose (2-deoxy- d -erythro-pentose) (C5H10O4, cr) have been determined by combustion bomb calorimetry. The following molar thermodynamic quantities are reported at T′ = 298.15 K: the standard enthalpy of combustion for d -ribose and 2-deoxy- d -ribose, ΔcHm∘(T′), −(2349.47±0.95) kJ·mol−1 and −(2527.39±0.98) kJ·mol−1, respectively; the standard enthalpy of formation, ΔfHm∘(T′), −(1047.23±1.66) kJ·mol−1 and −(869.31±1.68) kJ·mol−1, respectively. N.m.r. 1H and CP-MAS 13C studies were conducted to determine the anomeric composition of the crystalline sugars.
Sample-Averaged Biexciton Quantum Yield Measured by Solution-Phase Photon Correlation

The brightness of nanoscale optical materials such as semiconductor nanocrystals is currently limited in high excitation flux applications by inefficient multiexciton fluorescence. We have devised a solution-phase photon correlation measurement that can conveniently and reliably measure the average biexciton-to-exciton quantum yield ratio of an entire sample without user selection bias. This technique can be used to investigate the multiexciton recombination dynamics of a broad scope of synthetically underdeveloped materials, including those with low exciton quantum yields and poor fluorescence stability. Here, we have applied this method to measure weak biexciton fluorescence in samples of visible-emitting InP/ZnS and InAs/ZnS core/shell nanocrystals, and to demonstrate that a rapid CdS shell growth procedure can markedly increase the biexciton fluorescence of CdSe nanocrystals.
Developing countries' borrowing in the international financial market with an uncertain credit ceiling?

In the sovereign debt literature of the 1980s, countries formulated optimal borrowing plans subject to a credit ceiling imposed by their lenders. This paper analyzes the case where the credit ceiling is not known with certainty. The baseline deterministic model shows that consumption, investment and the current account deficit depend positively on the credit ceiling, implying more optimistic expectations about the country's future access to external financing led to larger current account deficits today. An extension of the model shows that when the country recognizes the uncertainty about future access to borrowing, optimal current account deficits are more moderate. Copyright © 2001 John Wiley & Sons, Ltd.
Clinical Experience With Subxiphoid Drainage of Pericardial Effusions

To assess the effectiveness of subxiphoid pericardial tube drainage for treatment of pericardial effusion, we reviewed 41 consecutive patients who underwent this procedure during a 14-year period. The patients ranged in age from 7 months to 75 years. All were symptomatic preoperatively. The diagnosis of pericardial effusion was confirmed by echocardiogram in all but 2 patients. Eight patients had acute pericardial tamponade. Subxiphoid pericardial drainage was performed under general (n = 35) or local anesthesia (n = 6). A portion of the anterior pericardium was excised in each patient. There were no perioperative deaths. Thirty-day mortality was 19.5%; there were five late deaths. All deaths were unrelated to pericardial effusion or to the operation. One patient had recurrent effusion requiring pericardiocentesis on the 21st postoperative day. He died five days later of extensive lymphoma. Twenty-eight patients were followed from 1 month to 10 years; mean follow-up was 31.5 months. None developed recurrent effusion or pericardial constriction. We conclude that subxiphoid pericardial drainage is effective for treatment of pericardial effusion.
A study of flow theory in the foreign language classroom

This article focuses on the relationship between flow experiences and language learning. Flow Theory suggests that flow experiences (characterized by a balance between challenge and skills and by a person's interest, control, and focused attention during a task) can lead to optimal learning. This theory has not yet been tested in the area of foreign or second language learning. The purpose of the present study is twofold: first, to establish the foundation for a research stream addressing flow in language learning, and second, to investigate whether flow exists in foreign language (FL) classrooms. Findings suggest that flow does exist in the FL classroom and that Flow Theory offers an interesting and useful framework for conceptualizing and evaluating language learning activities.
Exploring tin tantalates and niobates as prospective catalyst supports for water electrolysis

Abstract In an attempt to identify new electrochemically stable catalyst supports for electrolysis of water, the electronic structure of Sn2Ta2O7, Sn2Nb2O7, SnTa2O6, and SnNb2O6 compounds doped with small amounts of As, Sb, Bi, Cr, Mo, and W has been calculated using the Vienna ab-initio simulation package (VASP), within the projector augmented-wave (PAW) method in the general gradient approximation (GGA) for conducting the exchange-correlation corrections. The role of incorporating the additional 5A and 6B elements in improving the electronic conductivity is discussed. Based on the calculated values of the cohesive energies for the materials and their type of electronic conductivity, we hypothesize that the thoreaulite structure of SnTa2O6 doped with As, Sb, or Bi are the most appropriate candidates for use as catalyst supports in water electrolysis.
Robust coding for lossy computing with receiver-side observation costs

1An encoder wishes to minimize the bit rate necessary to guarantee that a decoder is able to calculate a symbol-wise function of a sequence available only at the encoder and a sequence that can be measured only at the decoder. This classical problem, first studied by Yamamoto, is addressed here by including two new aspects: (i) The decoder obtains noisy measurements of its sequence, where the quality of such measurements can be controlled via a cost-constrained “action” sequence; (ii) Measurement at the decoder may fail in a way that is unpredictable to the encoder, thus requiring robust encoding. The considered scenario generalizes known settings such as the Heegard-Berger-Kaspi and the “source coding with a vending machine” problems. The rate-distortion-cost function is derived in relevant special cases, along with general upper and lower bounds. Numerical examples are also worked out to obtain further insight into the optimal system design.
Conformal completion of the standard model with a fourth generation

We study dynamical electroweak symmetry breaking with a fourth generation within the Z n orbifolded AdS 5 ⊗ S 5 framework. A realistic Z 7 example is discussed. The initial theory reduces dynamically, due to the induced condensates, to a four-family trinification near a TeV-scale conformal fixed point where the gauge hierarchy problem does not exist. We predict new gauge bosons and bifundamental fermions and scalars accessible by the LHC.
Monster redshift surveys through dispersive slitless imaging: the Baryon Oscillation Probe

Wide-field imaging from space should not forget the dispersive dimension. We consider the capability of space-based imaging with a slitless grism: because of the low near-infrared background in space and the high sky-density of high redshift emission line galaxies this makes for a very powerful redshift machine with no moving parts. A small 1m space telescope with a 0.5 degree field of view could measure redshifts for 10 7 galaxies at 0.5 < z < 2 per year, this is a MIDEX class concept which we have dubbed ‘The Baryon Oscillation Probe’ as the primary science case would be constraining dark energy evolution via measurement of the baryonic oscillations in the galaxy power spectrum. These ideas are generalizable to other missions such as SNAP and DESTINY.
Heat Transfer in Turbulent Boundary Layers Subjected to Free-Stream Turbulence—Part I: Experimental Results

Turbulent boundary layers were subjected to grid-generated free-stream turbulence to study the effects of length scale and intensity on heat transfer Relative to conventional boundary layer thickness measures, test conditions included very small-scale free-stream turbulence. The boundary layers studied ranged from 400-2700 in momentum-thickness Reynolds number and from 450-1900 in enthalpy-thickness Reynolds number. Free-stream turbulence intensities varied from 0.1-8.0%. Ratios of free-stream length scale to boundary-layer momentum thickness ranged from 4.4-32.5. The turbulent-to-viscous length-scale ratios presented are the smallest found in the heat-transfer literature; the ratios spanned from 115-1020. The turbulent-to-thermal ratios (using enthalpy thickness as the thermal scale) are also the smallest reported; the ratios ranged from 3.2-12.3. Relative to clean-free-stream expectations based on the momentum- and enthalpy-thickness Reynolds numbers, the skin friction coefficient increased by up to 16%, and the Stanton number increased by up to 46%.
Asymmetric Boundary Layer on a Nonisothermally Heated Cone

The development of a three-dimensional boundary layer along a heated cone is analyzed. The surface of the cone is heated under the condition of constant wall heat flux. The perturbation solution is obtained for the flow close to the leading edge where the buoyancy force can be treated as a higher-order effect. A finite-difference solution is obtained for the flow far downstream from the leading edge where buoyancy is one of the cominant forces. The numerical results clearly describe the boundary-layer development along heated cones of different cone angles as well as the heat transfer rate. Boundary-layer stability is briefly discussed in terms of the boundary-layer shape factor.
Incentives to Identify: Racial Identity in the Age of Affirmative Action

Abstract We link data on racial self-identification with changes in statelevel affirmative action policies to ask whether racial self-identification responds to economic incentives. We find that after a state bans affirmative action, multiracial individuals who face an incentive to identify under affirmative action are about 30% less likely to identify with their minority group. In contrast, multiracial individuals who face a disincentive to identify under affirmative action are roughly 20% more likely to identify with their minority group once affirmative action policies are banned.
Time-constrained temporal logic control of multi-affine systems

Abstract In this paper, we consider the problem of controlling a dynamical system such that its trajectories satisfy a temporal logic property in a given amount of time. We focus on multi-affine systems and specifications given as syntactically co-safe linear temporal logic formulas over rectangular regions in the state space. The proposed algorithm is based on estimating the time bounds for facet reachability problems and solving a time optimal reachability problem on the product between a weighted transition system and an automaton that enforces the satisfaction of the specification. A random optimization algorithm is used to iteratively improve the solution.
Galaxy Structural Parameters: Star Formation Rate and Evolution with Redshift

The evolution of the structure of galaxies as a function of redshift is investigated using two parameters: the metric radius of the galaxy (Rη) and the power at high spatial frequencies in the disk of the galaxy (χ). A direct comparison is made between nearby (z~0) and distant (0.2 z 1) galaxies by following a fixed range in rest frame wavelengths. The data of the nearby galaxies comprise 136 broadband images at ~4500 A observed with the 0.9 m telescope at Kitt Peak National Observatory (23 galaxies) and selected from the catalog of digital images of Frei et al. (113 galaxies). The high-redshift sample comprises 94 galaxies selected from the Hubble Deep Field (HDF) observations with the Hubble Space Telescope using the Wide Field Planetary Camera 2 in four broad bands that range between ~3000 and ~9000 A (Williams et al.). The radius is measured from the intensity profile of the galaxy using the formulation of Petrosian, and it is argued to be a metric radius that should not depend very strongly on the angular resolution and limiting surface brightness level of the imaging data. It is found that the metric radii of nearby and distant galaxies are comparable to each other. The median value of the radius of the local sample is Rη ~ 5±1 kpc, and the median radius of the HDF sample is Rη ~ 6±2 kpc for q0 = 0.5, H0 = 65 km s-1 Mpc-1; however, for q0 = 0.1, Rη ~ 7 kpc and for q0 = 1, Rη ~ 5 kpc. In the HDF, galaxies with redshifts larger than z > 0.6 have flatter Rη distributions than galaxies with redshifts smaller than z ≤ 0.6. However, the median Rη values of high- and low-redshift galaxies are consistent with each other. This result is consistent with the simulations of galaxy images at redshifts z = 0.35, z = 0.5, and z = 0.9, which show that the metric sizes can be recovered within ±2 kpc. The flocculency or power at high spatial frequencies is quantified using a simple method that is based on surface photometry in one band and that depends on the size of the star-forming regions and on the intensity profile of the galaxy. In nearby galaxies, the flocculency is found to trace the star formation rate as χ is correlated with optical colors (B-V) and the strength of the hydrogen recombination lines (Hα). In the HDF, galaxies at redshifts smaller than z~1 and with fluxes brighter than B = 25 have values of χ similar to what is measured in nearby galaxies and to what is expected from simulations of distant galaxy images. Among the HDF galaxies, I find that at most 4% can be identified as dwarf galaxies with rates of star formation similar to NGC 4449 and NGC 1569. Most HDF galaxies are giants with star formation rates similar to those in nearby giant galaxies. In summary, in this study I have introduced a method to measure the metric sizes and flocculency of the two-dimensional light distribution of galaxies. As a result, I find that the high spatial frequency power is related to the star formation rate. Further, I find that the sizes and power at high spatial frequencies of HDF galaxies remain largely unchanged between the present epoch and redshifts lower than z~1.
The Stellar Populations and Evolution of Lyman Break Galaxies

Using deep near-infrared and optical observations of the Hubble Deep Field-North from the Hubble Space Telescope NICMOS and WFPC2 instruments and from the ground, we examine the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at 2.0 z 3.5 in order to investigate their stellar population properties. The ultraviolet-optical rest-frame SEDs of the galaxies are much bluer than those of present-day spiral and elliptical galaxies and are generally similar to those of local starburst galaxies with modest amounts of reddening. We use stellar population synthesis models to study the properties of the stars that dominate the light from LBGs. Under the assumption that the star formation rate is continuous or decreasing with time, the best-fitting models provide a lower bound on the LBG mass estimates. LBGs with L* UV luminosities are estimated to have minimum stellar masses ~1010 ☉, or roughly 1/10 that of a present-day L* galaxy, similar to the mass of the Milky Way bulge. By considering the photometric effects of a second stellar population component of maximally old stars, we set an upper bound on the stellar masses that is ~3-8 times the minimum mass estimate. The stellar masses derived for bright LBGs are similar to published estimates of their dynamical masses based on nebular emission line widths, suggesting that such kinematic measurements may substantially underestimate the total masses of the dark matter halos. We find only loose constraints on the individual galaxy ages, extinction, metallicities, initial mass functions, and prior star formation histories. Most LBGs are well fitted by models with population ages that range from 30 Myr to ~1 Gyr, although for models with subsolar metallicities a significant minority of galaxies are well fitted by very young (10 Myr), very dusty stellar populations, A(1700 A) > 2.5 mag. We find no galaxies whose SEDs are consistent with young (108 yr), dust-free objects, which suggests that LBGs are not dominated by first-generation stars and that such objects are rare at these redshifts. We also find that the typical ages for the observed star formation events are significantly younger than the time interval covered by this redshift range (~1.5 Gyr). From this, and from the relative absence of candidates for quiescent, non-star-forming galaxies at these redshifts in the NICMOS data that might correspond to the fading remnants of galaxies formed at higher redshift, we suggest that star formation in LBGs may be recurrent, with short duty cycles and a timescale between star formation events of 1 Gyr.
The number of regular semisimple conjugacy classes in the finite classical groups

Abstract Using generating functions, we enumerate regular semisimple conjugacy classes in the finite classical groups. For the general linear, unitary, and symplectic groups this gives a different approach to known results; for the special orthogonal groups the results are new.
Bifunctional Asymmetric Catalysis: Cooperative Lewis Acid/Base Systems

In the field of catalytic, asymmetric synthesis, there is a growing emphasis on multifunctional systems, in which multiple parts of a catalyst or multiple catalysts work together to promote a specific reaction. These efforts, in part, are result-driven, and they are also part of a movement toward emulating the efficiency and selectivity of nature’s catalysts, enzymes. In this Account, we illustrate the importance of bifunctional catalytic methods, focusing on the cooperative action of Lewis acidic and Lewis basic catalysts by the simultaneous activation of both electrophilic and nucleophilic reaction partners. For our part, we have contributed three separate bifunctional methods that combine achiral Lewis acids with chiral cinchona alkaloid nucleophiles, for example, benzoylquinine (BQ), to catalyze highly enantioselective cycloaddition reactions between ketene enolates and various electrophiles. Each method requires a distinct Lewis acid to coordinate and activate the electrophile, which in turn increase...
A demonstration of LISA laser communication

Over the past few years, questions have been raised concerning the use of laser communications links between sciencecraft to transmit phase information crucial to the reduction of laser frequency noise in the LISA science measurement. The concern is that applying medium frequency phase modulations to the laser carrier could compromise the phase stability of the LISA fringe signal. We have modified the table-top interferometer presented in Pollack and Stebbins (2006 Demonstration of the zero-crossing phasemeter with a LISA test-bed interferometer Class. Quantum Grav.) by applying phase modulations to the laser beams in order to evaluate the effects of such modulations on the LISA science fringe signal. We have demonstrated that the phase resolution of the science signal is not degraded by the presence of medium frequency phase modulations.
Validation and verification of decision making rules

A methodology for the validation and verification of decision making rules is presented. The methodology addresses the general problem of detecting problematic cases in a set of rules expressed as statements in formal logic. This representation of the decision rules makes the problem general in terms of application domains, and also provides an analytical base for defining errors. The approach is based on viewing a rule base as an organization of information that flows from one process (rule) to another. The key step in the methodology is the transformation of the set of decision rules into an equivalent Petri net. The static and dynamic properties of the resulting Petri net are shown to reveal patterns of structures that correspond to the problematic cases. The techniques presented in this paper are based on theory and are supported by software tools.
Calculations of impurity radiation and its effects on tokamak experiments

The impurity radiation for typical tokamak parameters has been numerically calculated using an "average-ion model". Coronal equilibrium values for the emission of oxygen, iron, molybdenum, tungsten and gold were determined from the steady-state solutions of a set of related rate equations which included the effects of electron collisional ionization and excitation, dielectronic and radiative recombination, Δn = 0 and Δn ≠ 0 line transitions, and bremsstrahlung. The results for oxygen, iron, and molybdenum compare very well with other calculations. Since impurities diffusing in a tokamak are not expected to be in coronal equilibrium, time-dependent radiation calculations were also performed. A comparison of these non-equilibrium loss rates with those calculated under the assumption of coronal equilibrium indicates that coronal radiation calculations do not significantly underestimate the moderate- and high-Z impurity radiation losses for neoclassical diffusion velocities in large tokamaks, such as Princeton Large Torus and Tokamak Fusion Test Reactor. Finally, the detailed steady-state emission rates were used to investigate the effects of various concentrations of impurities on the neτ requirements for breakeven, ignition, and Q = 5 beam-driven reactor experiments.
Building a Communication Bridge With Mobile Hubs

Mobile robots can be used as mobile hubs to provide communication services on-demand. This capability is especially valuable in disaster response scenarios where there is no communication infrastructure. In such scenarios, mobile hubs can provide a communication infrastructure in a dynamic fashion. In this paper, we study the problem of building a communication bridge between a source s and a destination t with mobile robots. Given a set of robots P and their initial locations, our goal is to find a subset S of robots and their final locations such that the robots in S create a communication bridge between s and t in their final locations. We introduce a new optimization problem for building communication bridges. The objective is to minimize the number of hubs (i.e., |S|), while simultaneously minimizing the robots' motion. The two mobility measures studied in this paper are: (i) maximum travel distance and (ii) total travel distance of the robots. For a geometric version of the problem where the robots must move onto the line segment [s, t], we present polynomial time algorithms which use the minimum number of hubs while remaining within a constant factor of a given motion measure.
Sensor/actuator placement for flexible space structures

A new approach for the placement of sensors and actuators in the active control of flexible space structures is developed. The approach converts the discrete nature of sensor and actuator positioning problems to a nonlinear programming optimization through approximation of the control forces and output measurements by spatially continuous functions. The locations of the sensors and actuators are optimized in order to move the transmission zeros of the system further to the left of the imaginary axis. This criterion for sensor/actuator placement can be useful for optimal regulation and tracking problems, as well as for low authority controller designs. Two performance metrics are considered for the optimization and are applied to the sensor/actuator positioning of a large-order flexible space structure. >
Stirring Up the Pot: Can Cooling Flows In Galaxy Clusters Be Quenched By Gas Sloshing?

X-ray observations of clusters of galaxies reveal the presence of edges in surface brightness and temperature, known as cold fronts. In relaxed clusters with cool cores, these commonly observed edges have been interpreted as evidence for the sloshing of the core gas in the cluster's gravitational potential. Such sloshing may provide a source of heat to the cluster core by mixing hot gas from the cluster outskirts with the cool-core gas. Using high-resolution N-body/Eulerian hydrodynamic simulations, we model gas sloshing in galaxy clusters initiated by mergers with subclusters. The simulations include merger scenarios with gas-filled and gasless subclusters. The effect of changing the viscosity of the intracluster medium is also explored, but heat conduction is assumed to be negligible. We find that sloshing can facilitate heat inflow to the cluster core, provided that there is a strong enough disturbance. Additionally, sloshing redistributes the gas in the cluster core, causing the gas to expand and decreasing the efficiency of radiative cooling. In adiabatic simulations, we find that sloshing can raise the entropy floor of the cluster core by nearly an order of magnitude in the strongest cases. If the ICM is viscous, the mixing of gases with different entropies is decreased and consequently the heat flux to the core is diminished. In simulations where radiative cooling is included, we find that although eventually a cooling flow develops, sloshing can prevent the significant buildup of cool gas in the core for times on the order of a Gyr for small disturbances and a few Gyr for large ones. If repeated encounters with merging subclusters sustain the sloshing of the central core gas, as is observed, this process can provide a relatively steady source of heat to the core, which can help prevent a significant cooling flow.
Minimum Dominating Sets in Scale-Free Network Ensembles

We study the scaling behavior of the size of minimum dominating set (MDS) in scale-free networks, with respect to network size N and power-law exponent γ, while keeping the average degree fixed. We study ensembles generated by three different network construction methods and we use a greedy algorithm to approximate the MDS. With a structural cutoff imposed on the maximal degree we find linear scaling of the MDS size with respect to N in all three network classes. Without any cutoff (kmax = N – 1) two of the network classes display a transition at γ ≈ 1.9, with linear scaling above and vanishingly weak dependence below, but in the third network class we find linear scaling irrespective of γ. We find that the partial MDS, which dominates a given z < 1 fraction of nodes, displays essentially the same scaling behavior as the MDS.
Application of Monte Carlo Algorithms to the Bayesian Analysis of the Cosmic Microwave Background

Power spectrum estimation and evaluation of associated errors in the presence of incomplete sky coverage; nonhomogeneous, correlated instrumental noise; and foreground emission are problems of central importance for the extraction of cosmological information from the cosmic microwave background (CMB).
Implications of World Trade Organisation accession for China's agricultural trade patterns

This paper examines the composition of China’s international trade from 1980 to 1997, with a focus on agriculture and a view towards understanding agriculture’s changing trade structure relative to other sectors. We analyse the time series behaviour of individually traded goods at the Standard Industrial Trade Classification three-digit level, categorised into three groups: agricultural commodities, ‘other’ primary commodities and manufactures. We find that China’s agricultural trade has expanded along comparative advantage lines in only a very modest way, suggesting that World Trade Organization membership will have a large impact on China’s agricultural trade patterns.
Diastereoselectivity in the heterogeneous hydrogenation reactions of phosphorous substituted olefins

Phosphorous substituted methylenecyclohexane olefins show enhanced diasteroselectivity in heterogeneous hydrogenation reactions using Pd/C. A model system, derived from 4-t-butylcyclohexanone was used to explore the effects of solvent polarity and catalyst on the reduction reaction. It was found that olefins hydrogenated with catalytic Pd/C in polar solvents afford the highest diastereoselectivities (>15:1).
Preference Evolution and Reciprocity

Abstract This paper provides an evolutionary theory of reciprocity as an aspect of preference interdependence. It is shown that reciprocal preferences, which place negative weight on the payoffs of materialists and positive weight on the payoffs of sufficiently altruistic individuals can invade a population of materialists in a class of aggregative games under both assortative and nonassortative matching. In comparison with simpler specifications of preference interdependence (such as pure altruism or spite), the survival of such preferences is therefore less sensitive to details of the evolutionary selection process. Journal of Economic Literature Classification Numbers: C72, D62.
Serial Sectioning for Examination of Photoreceptor Cell Architecture by Focused Ion Beam Technology

Structurally deciphering complex neural networks requires technology with sufficient resolution to allow visualization of single cells and their intimate surrounding connections. Scanning electron microscopy (SEM), coupled with serial ion ablation (SIA) technology, presents a new avenue to study these networks. SIA allows ion ablation to remove nanometer sections of tissue for SEM imaging, resulting in serial section data collection for three-dimensional reconstruction. Here we highlight a method for preparing retinal tissues for imaging of photoreceptors by SIA–SEM technology. We show that this technique can be used to visualize whole rod photoreceptors and the internal disc elements from wild-type (wt) mice. The distance parameters of the discs and photoreceptors are in good agreement with previous work with other methods. Moreover, we show that large planes of retinal tissue can be imaged at high resolution to display the packing of normal rods. Finally, SIA–SEM imaging of retinal tissue from a mouse model (Nrl −/− ) with phenotypic changes akin to the human disease enhanced S-cone syndrome (ESCS) revealed a structural profile of overall photoreceptor ultrastructure and internal elements that accompany this disease. Overall, this work presents a new method to study photoreceptor cells at high structural resolution that has a broad applicability to the visual neuroscience field. Published by Elsevier B.V.
Sum rules for Jacobi matrices and divergent Lieb–Thirring sums

Abstract Let E j be the eigenvalues outside [ - 2 , 2 ] of a Jacobi matrix with a n - 1 ∈ l 2 and b n → 0 , and μ ′ the density of the a.c. part of the spectral measure for the vector δ 1 . We show that if b n ∉ l 4 , b n + 1 - b n ∈ l 2 , then ∑ j ( | E j | - 2 ) 5 / 2 = ∞ and if b n ∈ l 4 , b n + 1 - b n ∉ l 2 , then ∫ - 2 2 ln ( μ ′ ( x ) ) ( 4 - x 2 ) 3 / 2 dx = - ∞ . We also show that if a n - 1 , b n ∈ l 3 , then the above integral is finite if and only if a n + 1 - a n , b n + 1 - b n ∈ l 2 . We prove these and other results by deriving sum rules in which the a.c. part of the spectral measure and the eigenvalues appear on opposite sides of the equation.
Complex carbohydrate synthesis tools for glycobiologists: enzyme-based approach and programmable one-pot strategies

The ultimate goal in complex carbohydrate synthesis is to develop synthetic tools which are simple and easily accessible to glycobiologists. This review will describe methods which have the potential to reach this goal, with particular focus on enzymatic and computer-based one-pot approaches for the preparation of complex carbohydrates and glycoconjugates.
STATE ENCODING OF FINITE STATE MACHINES FOR LOW POWER DESIGN

We address the problem of state encoding for synchronous finite state machines (FSMs), targeted for low power design. Most previous work in FSM state encoding has been focused on minimizing chip area and does not consider switching activity of the circuit. As a result, this does not always lead to a power efficient implementation. Especially in CMOS circuits, the switching activity is a very important factor to power dissipation. In this work, we define a function λ for automatic tradeoff between switching activity and area that contribute to power dissipation. λ is used in determining the encoding affinity between states and is observed to be related to the number of states of an FSM in our experiments. A state encoding algorithm, based on hypercube embedding, is proposed to find encodings of states such that the sum of bit toggles between each pair of states times the encoding affinity between them is minimized. The proposed approach does not require any change in the functional specification of the state machine and can be easily incorporated in present design flow. Results over a wide range of MCNC benchmark examples which show the efficacy of our technique are presented. A simple function for λ is provided, and it is shown to be robust in finding low-power state encodings.
Corporate Prediction Markets: Evidence from Google, Ford, and Firm X

Despite the popularity of prediction, markets among economists, businesses, and policymakers have been slow to adopt them in decision-making. Most studies of prediction markets outside the lab are from public markets with large trading populations. Corporate prediction markets face additional issues, such as thinness, weak incentives, limited entry, and the potential for traders with biases or ulterior motives—raising questions about how well these markets will perform. We examine data from prediction markets run by Google, Ford Motor Company, and an anonymous basic materials conglomerate (Firm X). Despite theoretically adverse conditions, we find these markets are relatively efficient, and improve upon the forecasts of experts at all three firms by as much as a 25% reduction in mean-squared error. The most notable inefficiency is an optimism bias in the markets at Google. The inefficiencies that do exist generally become smaller over time. More experienced traders and those with higher past performance trade against the identified inefficiencies, suggesting that the markets' efficiency improves because traders gain experience and less skilled traders exit the market.
Osteogenic sarcoma in children

Abstract One hundred and thirty children less than 16 years of age with pathologically verified osteogenic (skeletogenic) sarcoma were seen during a 30-year period (1925-1955) with a minimum follow-up of ten years. This age group represents 23.6 per cent of the authors' total experience with skeletogenic sarcoma. The absolute survival for the entire series was 18.5 per cent at five years and 16.2 per cent at ten years. No child with an osseous tumor elsewhere than in an extremity had longterm survival. Amputation was the only “curative” method of therapy; 23 per cent of patients so treated were alive at five years and 20 per cent were alive at ten years. Radiation was never “curative” when used as the sole method of therapy, and treatment failure was higher in the group of patients who were treated with preoperative irradiation and then amputation than in the group treated by amputation alone. Prognosis varied with the size of the tumor—the smaller the better. The most important factor in prognosis was the histologic subgrouping of osteogenic sarcoma. No evidence was found to support a belief that there are considerable differences between skeletogenic sarcomas in children and in adults.