cssi/SciSciGPT-SciSciNet huggingface dataset:
A comparison of linking and concurrent calibration under item response theory

Applications of item response theory (IRT) to practical testing problems, including equating, differential item functioning, and computerized adaptive testing, require a common metric for item parameter estimates. This study compared three methods for developing a common metric under IRT: (1) linking separate calibration runs using equating coefficients from the characteristic curve method, (2) concurrent calibration based on marginal maximum a posteriori estimation, and (3) concurrent calibration based on marginal maximum likelihood estimation. For smaller numbers of common items, linking using the characteristic curve method yielded smaller root mean square differences for both item discrimination and difficulty parameters. For larger numbers of common items, the three methods yielded similar results.
Embedded associated primes of powers of square-free monomial ideals

Abstract An ideal I in a Noetherian ring R is normally torsion-free if Ass ( R / I t ) = Ass ( R / I ) for all t ≥ 1 . We develop a technique to inductively study normally torsion-free square-free monomial ideals. In particular, we show that if a square-free monomial ideal I is minimally not normally torsion-free then the least power t such that I t has embedded primes is bigger than β 1 , where β 1 is the monomial grade of I , which is equal to the matching number of the hypergraph H ( I ) associated to I . If, in addition, I fails to have the packing property, then embedded primes of I t do occur when t = β 1 + 1 . As an application, we investigate how these results relate to a conjecture of Conforti and Cornuejols.
HNF4A is essential for specification of hepatic progenitors from human pluripotent stem cells

The availability of pluripotent stem cells offers the possibility of using such cells to model hepatic disease and development. With this in mind, we previously established a protocol that facilitates the differentiation of both human embryonic stem cells and induced pluripotent stem cells into cells that share many characteristics with hepatocytes. The use of highly defined culture conditions and the avoidance of feeder cells or embryoid bodies allowed synchronous and reproducible differentiation to occur. The differentiation towards a hepatocyte-like fate appeared to recapitulate many of the developmental stages normally associated with the formation of hepatocytes in vivo. In the current study, we addressed the feasibility of using human pluripotent stem cells to probe the molecular mechanisms underlying human hepatocyte differentiation. We demonstrate (1) that human embryonic stem cells express a number of mRNAs that characterize each stage in the differentiation process, (2) that gene expression can be efficiently depleted throughout the differentiation time course using shRNAs expressed from lentiviruses and (3) that the nuclear hormone receptor HNF4A is essential for specification of human hepatic progenitor cells by establishing the expression of the network of transcription factors that controls the onset of hepatocyte cell fate.
Identification of chemical processes using canonical variate analysis

Abstract A method of identification of linear input-output models using canonical variate analysis (CVA) is developed for application to chemical processes. This approach yields both a process model and a nonparametric description of model uncertainty, utilizing CVA for selection of a state coordinate system that optimally relates past inputs and outputs to future outputs. Regression procedures are then used for estimation of the state-space model parameters, and the Akaike Information Criterion (AIC) is used to determine the model order. The primary computations involve singular value decompositions which are numerically stable and accurate. The effectiveness of the CVA approach is first evaluated with simulated chemical processes that exhibit most of the practical problems encountered by existing system identification methods: nonlinear dynamics, unknown model orders and time delays, nonminimum phase dynamics, partial stiffness (requiring two time-scale approaches when other identification methods are used), low input excitation in some frequency bands, and measurement and process noise. The CVA methodology is then applied to the identification of models for a pilot-scale distillation column.
What's new in obstetric anesthesia: the 2011 Gerard W. Ostheimer lecture.

Abstract The Gerard W. Ostheimer lecture is delivered at the Society for Obstetric Anesthesia and Perinatology Annual Meeting. The lecture provides a comprehensive review of the previous year’s literature in obstetric anesthesia, obstetrics, perinatology, and health services research relevant for obstetric anesthesiologists. This article covers several of the major themes that emerged from the 2010 literature.
Theoretical studies of the binding of methylamine and guanidine to carboxylate

Abstract Ab-initio (Hartree—Fock) calculations with the 6-31G and 6–31* Gaussian basis sets are used to investigate the guanidinium ion — carboxylate ion interaction and the methyl-amine — carboxylate ion interaction. The calculations predict that the former is more stable as a zwitterion while the latter probably exists as a neutral—neutral complex in a solvent-free medium. It is also found that there is no barrier to the transfer of a proton from one species to the other.
Development of structural composite mirror technology for submillimeter space telescopes

The technical approach to the design, manufacturing, testing, and analytical simulation of lightweight graphite/epoxy mirrors is described. The precision segmented reflector (PSR) program has produced (1) 1.0-m graphite/epoxy panels with areal densities of 7 kg/sq m as-manufactured surface precision near 1 micron rms, (2) 0.5-m panels with figure changes less than 1 micron rms for temperature reductions of 100 K, (3) analytical performance-prediction capability with submicron accuracy relative to panel thermal distortion, and (4) a unique thermal vacuum test facility for structural composite mirrors.
No-Go theorem in spacetimes with two commuting spacelike killing vectors

Four-dimensional Riemannian spacetimes with two commuting spacelike Killing vectors are studied in Einstein's theory of gravity, and found that no outer apparent horizons exist, provided that the dominant energy condition holds.
URINARY CONCENTRATION OF GONADOTROPHIN (ICSH)-INHIBITING SUBSTANCE IN STEIN-LEVENTHAL SYNDROME.

The urinary concentration of gonadotrophin (ICSH)-inhibiting substance was found to be markedly reduced to absent in 5 patients with Stein-Leventhal syndrome, while it was present in amounts usually found in normal subjects in one patient with mild adrenal cortical hyperplasia. It is possible that the Stein-Leventhal syndrome may result from the unregulated action of ICSH on the ovary, associated with a reduction in the postulated secretion of “inhibitor.”
Nitrosation of aryl and heteroaryltrifluoroborates with nitrosonium tetrafluoroborate.

Organotrifluoroborates have emerged as an alternative to toxic and air- and moisture-sensitive organometallic species for the synthesis of functionalized aryl and heteroaryl compounds. It has been shown that the trifluoroborate moiety can be easily converted into a variety of different substituents in a late synthetic stage. In this paper, we disclose a mild, selective, and convenient method for the ipso-nitrosation of organotrifluoroborates using nitrosonium tetrafluoroborate (NOBF4). Aryl- and heteroaryltrifluoroborates were converted into the corresponding nitroso products in good to excellent yields. This method proved to be tolerant of a broad range of functional groups.
Adaptive Signal Detection with Finite Memory

The purpose of this presentation is to develop and evaluate an algorithm for determining a finite memory detector applicable to statistical signal detection theory. In the Bayesian signal detection theory, infinite soft or changeable memory is tacitly assumed. Since an infinite memory is physically unrealizable, this study postulates a finite memory scheme which is applicable to a large class of signal detection problems. A general sequentially operating finite memory detector design is obtained and then evaluated for the signal known exactly and the signal known except amplitude problems. Detection performance as a function of memory size is presented for finite observation records using the receiver operating characteristic and plots of probability of decision error versus time. These results show the tradeoff between memory size and processing time to achieve a given detection performance. An important result is that for finite sample records a small finite memory detector with a memory size on the order of 7 states, i.e., a 3-bit computer word, yields detection performance very near that of the optimum infinite memory detector.
Capital budgeting and delegation

Abstract As part of our ongoing research into capital budgeting processes as responses to decentralized information and incentive problems, we focus in this paper on when a level of a managerial hierarchy will delegate the allocation of capital across projects and time to the level below it. In our model, delegation is a way to save on costly investigation of proposed projects. Therefore, it is more extensive the larger are the costs of such investigations. This delegation takes advantage of the fact that the lower-level manager's preferences are assumed to be similar (though not identical) to those of the higher level.
Adverse Selection and Competitive Market Making: Empirical Evidence from a Limit Order Market

This article presents a new methodology for testing economic restrictions on the price schedules offered in a limit order book that are based on (i) break-even conditions for marginal limit orders and (ii) rational updating conditions for order book revisions over time. Using order flow data from the Stockholm Stock Exchange, I find strong evidence of insufficient depth in the limit order books relative to the theoretical predictions. An extended model, which allows the model parameters to depend on market conditions, captures some of the systematic variation in the observed order book depth. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
A geomagnetic cutoff rigidity interpolation tool: Accuracy verification and application to space weather

Abstract We have developed a fast and accurate geomagnetic vertical cutoff rigidity interpolation tool that has general space weather applications. The interpolation tool utilizes vertical cutoff rigidity values determined from 5° by 5° world grids of geomagnetic cutoff rigidities obtained by tracing cosmic ray trajectories through the Tsyganenko magnetospheric field model combined with the International Geomagnetic Reference Field. The world grids for each UT hour were calculated for a 450-km satellite altitude for all magnetic conditions parameterized by the integer magnetic Kp index ranging from very quiet to extremely disturbed. The interpolation tool extrapolates from the grid positions at 450 km to any other position or altitude. We demonstrate the accuracy of vertical geomagnetic cutoff values obtained from this interpolation tool by reproducing the orbital radiation dose profile from solar protons recorded during the STS-28 space shuttle mission. We also predict the cutoff latitudes of the 8–15 MeV per nucleon α particle flux and compare these values with those determined by the SAMPEX (Solar Anomalous and Magnetospheric Particle Explorer) spacecraft observations for six independent solar particle events under a variety of geomagnetic conditions. In general our predicted cutoff latitudes are within about one degree of the observed cutoff latitudes for low levels of geomagnetic activity.
Short-run and Long-run Expectations of the Yen/Dollar Exchange Rate

Abstract The survey data of the yen/dollar exchange rate, collected twice a month for eight years from 1985 to 1993, show the following features. First, the expected exchange rate changes in the short horizon (one month) are of the bandwagon type while the expected changes in the long horizon (three to six months) are of the mean-reversion type. That is, foreign exchange traders infer from recent appreciation or depreciation that the recent change in the exchange rate will continue for a while, but the direction of changes will reverse, eventually. Second, this result is robust for the entire sample period, which includes sub-periods of sharp yen appreciations and of relative calm, and with respect to different specifications. Third, the deviation from an equilibrium exchange rate does not yield a robust estimate in the regression of expectation formation. Although the history of the yen/dollar exchange rate fluctuations in the past two decades shows mean reversion over several years, they are not captured in the six-month expectations in the survey data. J. Japan. Int. Econ., June 1994, 8 (2), pp. 119–143. Belfer 409, Kennedy School of Government, Harvard University, Cambridge, MA 02138; Hitotsubashi University, Tokyo 186, Japan; and National Bureau of Economic Research, Cambridge, MA 02138.
Intermolecular pinacol cross coupling of aryl aldehydes or their dimethyl acetals with non-aryl aldehydes

Abstract 1-Aryl-2-alkyl-1,2-ethanediols have been synthesized via intermolecular pinacol cross coupling of aryl with non-aryl aldehydes. Dimethyl acetals of aryl aldehydes can also be cross coupled with non aryl aldehydes to yield 2-aryl-2-methoxy-1-alkyl-1-ethanols. The reaction is accomplished employing the vanadium(II) reagent [V2Cl3(THF)6]2[Zn2Cl6] which is prepared in situ from VCl3(THF)3.
Development of Protective Coatings for High-Temperature Metallic Materials

Metallic material systems with potential for high-temperature operations are critical for many land-based and space-based systems. Advanced alloys with improved elevated temperature properties and/or reduced densities offer improved structural ef"icieney and longer service life compared to more conventional alloys. However, in extreme operating environments, these alloys require coatings for environmental protection and thermal control. We discuss some results from a program to develop ultrathin, lightweight, protective coatings applied via sol-gel techniques for some emerging high-temperature alloys. The coatings were designed to reduce oxidation, increase emittance, and reduce the catalytic efficiency for recombination of dissociated hot-gas species for the candidate materials. The alloys considered in this study include PM1000 (an oxide dispersion strengthened Ni-based alloy), 602CA Ni-based alloy, and a gamma titanium aluminide alloy. Inconel 617, a Ni-based alloy, was included as a reference. Microstructural analysis and oxidation weight gain results indicated that the coatings significantly reduced oxidation damage during extended high-temperature exposures for these alloys. In addition, one coating system was shown to improve the emittance of Inconel 617. A substantial reduction in the recombination of atomic nitrogen and oxygen at the surface of Inconel 617 substrates in a hot flowing airstream was also observed.
Versatile Gate for Artificial Neural Network Circuit

versatile gate is a multipurpose device, which can be transformed into any types of gates, amplifier, differentiator, and integrator. It has control inputs which guides transformation of this device. This implies that any chip made of this device can change hardware structure just by using software program. This enables hardware upgrading without buying new chips. This reduces electronic wasteland, which proves that it is very ergonomic and environmental friendly.
Sklyanin algebras and Hilbert schemes of points

We construct projective moduli spaces for torsion-free sheaves on noncommutative projective planes. These moduli spaces vary smoothly in the parameters describing the noncommutative plane and have good properties analogous to those of moduli spaces of sheaves over the usual (commutative) projective plane P2. The generic noncommutative plane corresponds to the Sklyanin algebra S=Skl(E,σ) constructed from an automorphism σ of infinite order on an elliptic curve E⊂P2. In this case, the fine moduli space of line bundles over S with first Chern class zero and Euler characteristic 1−n provides a symplectic variety that is a deformation of the Hilbert scheme of n points on P2∖E.
The Cross‐Sectional Relationship Between Trading Costs and Lead/Lag Effects in Stock & Option Markets

Prior empirical research has failed to settle the question of lead/lag effects between stock and option markets. This study investigates the relation between cross-sectional differences in trading costs and intraday lead/lag effects in stock and option markets. The data for the study comprise 19 firms sampled at five-minute intervals over a two-month period. Consistent with a trading cost hypothesis, results indicate overall stock market leading behavior. However, the lead appears to be related to option market trading costs. This study uses an error correction model framework to investigate the lead/lag effects. This approach provides information on both the long run equilibrating process as well as the short term interactions between stock and option markets. Information regarding the long run equilibrating process is important to the overall understanding of lead/lag effects and cannot be determined from time series models of differenced data. Specific criteria for assessing lead/lag effects in cointegrated series are also proposed. One advantage of these new criteria is their ability to identify leading behavior in the presence of feedback. All models are estimated with quote data and are constructed to eliminate overnight effects. Hence, the results are robust to previously identified distortions due to closing, overnight, and potential non-trading effects. However, caution should be employed in generalizing the results as the study covers a two-month trading period for a limited number of firms.
Kontsevich's Universal Formula for Deformation Quantization and the Campbell-Baker-Hausdorff Formula, I

We relate a universal formula for the deformation quantization of Poisson structures (⋆-products) on ℝd proposed by Maxim Kontsevich to the Campbell–Baker–Hausdorff (CBH) formula. We show that Kontsevich's formula can be viewed as exp(P) where P is a bi-differential operator that is a deformation of the given Poisson structure. For linear Poisson structures (duals of Lie algebras) his product takes the form exp(C+L) where exp(C) is the ⋆-product given by the universal enveloping algebra via symmetrization, essentially the CBH formula. This is established by showing that the two products are identical on duals of nilpotent Lie algebras where the operator L vanishes. This completely determines part of Kontsevich's formula and leads to a new scheme for computing the CBH formula. The main tool is a graphical analysis for bi-differential operators and the computation of certain iterated integrals that yield the Bernoulli numbers.
Design and fabrication of inverted rib waveguide Bragg grating

A polymeric SU8 rib waveguide Bragg grating filterfabricated using reactive ion etching (RIE) and solvent assisted microcontact molding (SAMIM) is presented. SAMIM is one kind of soft lithography. The technique is unique in which that a composite hPDMS/PDMS stamp was used to transfer the grating pattern onto an inverted SU8 rib waveguide system. The composite grating stamp can be used repeatedly several times with degradation. Using this stamp and inverter rib waveguide structure, the Bragg grating filter fabrication can be significantly simplified.
The Power Spectrum of Rich Clusters on Near-Gigaparsec Scales

Recently, there have been numerous analyses of the redshift space power spectrum of rich clusters of galaxies. Some of these analyses indicate a ``bump'' in the Abell/ACO cluster power spectrum around k = 0.05 h Mpc-1. Such a feature in the power spectrum excludes most standard formation models and indicates possible periodicity in the distribution of large-scale structure. However, the data used in detecting this peak include clusters with estimated redshifts and/or clusters outside of G. O. Abell's statistical sample, i.e., R = 0 clusters. Here we present estimates of the redshift space power spectrum for a newly expanded sample of 637 R ≥ 1 Abell/ACO clusters which has a constant number density to z = 0.10 in the southern hemisphere and a nearly constant number density to z = 0.14 in the northern hemisphere. The volume sampled, ~108 h-3 Mpc3, is large enough to accurately calculate the power per mode to scales approaching 103 h-1 Mpc. We find the shape of the power spectrum is a power law on scales 0.02 ≤ k ≤ 0.10 h Mpc-1, with enhanced power over less rare clusters such as APM clusters. The power law here follows n = -1.4. The power spectrum is essentially featureless, although we do see a dip near k = 0.04 h Mpc-1, which cannot be considered statistically significant based on this data alone. We do not detect a narrow peak at k ~ 0.05 h Mpc-1, and there is no evidence for a turnover in the power spectrum as has been previously reported. We compare the shape of the Abell/ACO rich cluster power spectrum to various linear models.
Theoretical investigations of the excited-state intramolecular proton transfer reaction in N-substituted-3-hydroxypyridinones

Abstract The potential energy functions of the electronic ground state, as well as the lowest n π ∗ and ππ ∗ excited singlet states of 3-hydroxy-4-pyridinone and 3-hydroxy-2-methyl-4-pyridinone, have been theoretically investigated along the proton transfer (PT) reaction coordinate. The full geometry optimization has been performed along the PT reaction path. In the geometry optimization, the Hartree-Fock approximation and the configuration interaction scheme with single excitations have been employed. The energy calculations at the optimized geometries have been performed with the complete-active space self-consistent field (CASSCF) method followed by second-order perturbation theory calculations, employing the CASSCF wave function as the reference. We found that the near-degeneracy between the ππ ∗ and n π ∗ excited singlet states, which is removed upon methyl substitution, might be the factor which differentiates the two systems with respect to the excited state intramolecular PT reaction. A simple vibrational model has been proposed for investigation of the dynamics of the process.
The Stellarator Concept

The basic concepts of the controlled thermonuclear program at Project Matterhorn, Princeton University are discussed. In particular, the theory of confinement of a fully ionized gas in the magnetic configuration of the stellarator is given, the theories of heating are outlined, and the bearing of observational results on these theories is described.Magnetic confinement in the stellarator is based on a strong magnetic field produced by solenoidal coils encircling a toroidal tube. The configuration is characterized by a ``rotational transform,'' such that a single line of magnetic force, followed around the system, intersects a cross‐sectional plane in points which successively rotate about the magnetic axis. A theorem by Kruskal is used to prove that each line of force in such a system generates a toroidal surface; ideally the wall is such a surface. A rotational transform may be generated either by a solenoidal field in a twisted, or figure‐eight shaped, tube, or by the use of an additional transverse multipolar helical field, with helical symmetry.Plasma confinement in a stellarator is analyzed from both the macroscopic and the microscopic points of view. The macroscopic equations, derived with certain simplifying assumptions, are used to show the existence of an equilibrium situation, and to discuss the limitations on material pressure in these solutions. The single‐particle, or microscopic, picture shows that particles moving along the lines of force remain inside the stellarator tube to the same approximation as do the lines of force. Other particles are presumably confined by the action of the radial electric field that may be anticipated.Theory predicts and observation confirms that initial breakdown, complete ionization, and heating of a hydrogen or helium gas to about 106 degrees K are possible by means of a current parallel to the magnetic field (ohmic heating). Flow of impurities from the tube walls into the heated gas, during the discharge, may be sharply reduced by use of an ultra‐high vacuum system; some improvement is also obtained with a divertor, which diverts the outer shell of magnetic flux away from the discharge. Experiments with ohmic heating verify the presence of a hydromagnetic instability predicted by Kruskal for plasma currents greater than a certain critical value and also indicate the presence of other cooperative phenomena. Heating to very much higher temperatures can be achieved by use of a pulsating magnetic field. Heating at the positive‐ion cyclotron resonance frequency has been proposed theoretically and confirmed observationally by Stix. In addition, an appreciable energy input to the positive ions should be possible, in principle, if the pulsation period is near the time between ion‐ion collisions or the time required for a positive ion to pass through the heating section (magnetic pumping).
Synthesis of α,α-dichloroalcohols, α-hydroxyketones and 1-chloro-1-arylalkylene oxides via protonation of acyllithium reagents

Abstract The protonation of acyllithium reagents generated in situ from alkyllithiums and carbon monoxide in the presence of dichloromethane or dichloroarylmethanes produces α , α -dichloroalcohols in high yields. The reaction produces α -hydroxy-ketones in high yields when the aryl group of dichloroarylmethane contains a strong electron-donating group at the ortho or para position. The transformation of α , α -dichloro- α -aryl alcohols into 1-chloro-1-arylalkylene oxides is achieved in high yields by using sodium amide as a base.
Nutritional surveillance in the USA

The Center for Disease Control (CDC), United States Department of Health, Education and Welfare, is working towards the development of an efficient and effective surveillance system that will:
A Self-consistent Model for the Formation of Relativistic Outflows in Advection-dominated Accretion Disks with Shocks

In this Letter, we suggest that the relativistic protons powering the outflows emanating from radio-loud systems containing black holes are accelerated at standing, centrifugally supported shocks in hot advection-dominated accretion disks. Such disks are ideal sites for first-order Fermi acceleration at shocks because the gas is tenuous, and consequently the mean free path for particle-particle collisions generally exceeds the thickness of the disk. The accelerated particles are therefore able to avoid thermalization, and as a result a small fraction of them achieve very high energies and escape from the disk. In our approach, the hydrodynamics and the particle acceleration are coupled and the solutions are obtained self-consistently based on a rigorous mathematical treatment. The theoretical analysis of the particle transport parallels the early studies of cosmic-ray acceleration in supernova shock waves. We find that particle acceleration in the vicinity of the shock can extract enough energy to power a relativistic jet. Using physical parameters appropriate for M87 and Sgr A*, we confirm that the jet kinetic luminosities predicted by the theory agree with the observational estimates.
An Evolving Entropy Floor in the Intracluster Gas

Nongravitational processes, such as feedback from galaxies and their active nuclei, are believed to have injected excess entropy into the intracluster gas, and therefore to have modified the density profiles in galaxy clusters during their formation. Here we study a simple model for this so-called preheating scenario, and ask (1) whether it can simultaneously explain both global X-ray scaling relations and number counts of galaxy clusters, and (2) whether the amount of entropy required evolves with redshift. We adopt a baseline entropy profile that fits recent hydrodynamic simulations, modify the hydrostatic equilibrium condition for the gas by including ≈20% nonthermal pressure support, and add an entropy floor K0 that is allowed to vary with redshift. We find that the observed luminosity-temperature (L − T) relations of low-redshift ( z = 0.05) HIFLUGCS clusters and high-redshift ( z = 0.80) WARPS clusters are best simultaneously reproduced with an entropy floor that evolves from ≈200 h−1/3 keV cm 2 at z ≈ 0.8 to 300 h−1/3 keV cm 2 at z < 0.05. This evolution may take place predominantly at low redshift (z 0.2). If we restrict our analysis to the subset of bright (kT 3 keV) clusters, we find that the evolving entropy floor can mimic a self-similar evolution in the L − T scaling relation. This degeneracy with self-similar evolution is, however, lifted when 0.5 keV kT 3 keV clusters are included. Using the cosmological parameters from the WMAP 3 yr data, but treating σ8 as a free parameter, our model can reproduce the number counts of the X-ray galaxy clusters in the 158 deg2 ROSAT PSPC survey, with a best-fit value of σ8 = 0.80 ± 0.05.
Holomorphic one-forms on varieties of general type

Abstract It has been conjectured that varieties of general type do not admit nowhere vanishing holomorphic one-forms. We confirm this conjecture for smooth minimal varieties and for varieties whose Albanese variety is simple.
Group representations that resist random sampling

Author(s): Lovett, S; Moore, C; Russell, A | Abstract: We show that there exists a family of groups Gn and nontrivial irreducible representations ρn such that, for any constant t, the average of ρn over t uniformly random elements g1,...,gt∈Gn has operator norm 1 with probability approaching 1 as n→∞. More quantitatively, we show that there exist families of finite groups for which Ω(loglog|G|) random elements are required to bound the norm of a typical representation below 1. This settles a conjecture of A. Wigderson.
Chandra Low Energy Transmission Grating Spectrum of SS Cygni in Outburst

We have fitted the Chandra Low Energy Transmission Grating spectrum of SS Cygni in outburst with a single temperature blackbody suffering the photoelectric opacity of a neutral column density and the scattering opacity of an outflowing wind. We find that this simple model is capable of reproducing the essential features of the observed spectrum with the blackbody temperature T{sub bl} {approx} 250{+-}50 kK, hydrogen column density N{sub H} {approx} 5.0{sup +2.9}{sub -1.5}x10{sup 19} cm{sup -2}, fractional emitting area f {approx} 5.6{sup +60}{sub -4.5} x10{sup -3}, boundary layer luminosity Lbl {approx} 5{sup +18}{sub -3} x10{sup 33} erg s{sup -1}, wind velocity v {approx} 2500 km s{sup -1}, wind mass-loss rate w {approx} 1.1x10{sup 16} g s{sup -1}, and arbitrary values of the wind ionization fractions of 20 ions of O, Ne,Mg, Si, S, and Fe. Given that in outburst the accretion disk luminosity L{sub disk} {approx}1x10{sup 35} erg s{sup -1}, L{sub bl}/L{sub disk} {approx} 0.05{sup +0.18}{sub -0.03}, which can be explained if the white dwarf (or an equatorial belt thereon) is rotating with an angular velocity {Omega}{sub wd} {approx} 0.7{sup +0.1}{sub -0.2}Hz, hence V{sub rot}sini {approx} 2300 km s{sup -1}.
Welfare bounds in the fair division problem

To any anonymous division method corresponds a lower and an upper bound function: they measure the impact on a given agent's utility of the other agents' preferences. The highest lower bound is the equal split utility; the lowest upper bound is the indirect utility from equal split at a “canonical” price. These two bounds are compatible. Yet any method with the elqual split lower bound exhibits the growth paradox, and any method with the lowest upper bound generates envy. We criticize Competitive Equilibrium from Equal Split because it puts no finite upper bound on any agent's welfare.
Modeling of orthotropic elastic-plastic properties of ARALL laminates

Abstract The elastic-plastic behavior of an ARALL (Aramid aluminum laminate) laminate is modeled by a macromechanical orthotropic plasticity theory and by classical laminated plate theory. In the orthotropic plasticity model, a three-parameter plastic potential function is used. In the laminated plate theory, the Kevlar composite layers are assumed to be linearly elastic and the aluminum layers, orthotropic elastic-plastic. Comparison with experimental results indicates that the orthotropic plasticity model is reasonably accurate up to a total strain of 1·2%. The laminated plate theory is found to be capable of describing the stress-strain curves up to a failure.
Symmetry rules for chemical reactions

Abstract The symmetry properties of molecular orbitals and of reaction coordinates can be used to decide on the feasibility of selected chemical reaction mechanisms. Some reaction paths are shown to have a large energy barrier and are said to be “forbidden by orbital symmetry.” The reactions of molecules with no symmetry can also be analyzed by being compared to related symmetric molecules, where the molecular orbitals are topological identical.
Creeping motion in granular flow.

The core of a quasi-two-dimensional rotating cylinder filled more than half full with glass beads rotates slightly faster than the cylinder itself and decreases in radius over time. Core precession depends linearly on the number of tumbler revolutions while core erosion varies logarithmically. Both processes serve to quantify the slow granular motion in the ``fixed'' bed and depend on the filling fraction and the tumbler rotation rate. A simple model, based on experimental observations of an exponential decrease in velocity parallel to the free surface, captures the primary features of the core dynamics.
Nucleophilic Trifluoromethylation of Carbonyl Compounds: Trifluoroacetaldehyde Hydrate as a Trifluoromethyl Source

A feasible nucleophilic trifluoromethylating protocol has been developed using trifluoroacetaldehyde hydrate as an atom-economical trifluoromethyl source. The reaction was found to be applicable to the nucleophilic trifluoromethylation of a broad spectrum of carbonyl compounds with satisfactory yields in general. DFT calculations have been performed to provide mechanistic insight into the present and related reactions employing 2,2,2-trifluoro-1-methoxyethanol and hexafluoroacetone hydrate.
On-Line Routing of Real-Time Messages

The problem of routing unit-length, real-time messages in a distributed system is considered. An on-line routing algorithm is one that routes messages without any knowledge of future arrivals of messages. An on-line algorithm is said to be optimal if it produces a feasible route whenever one exists. In this article, we study the issue whether it is possible to have an optimal on-line algorithm for the following networks?unidirectional ring, out-tree, in-tree, bidirectional tree, and bidirectional ring. The problem is considered under various restrictions of the four parameters?origin node, destination node, release time, and deadline. We show that: (1) for a unidirectional ring, no such algorithm can exist unless one of the four parameters is fixed (i.e., all messages have identical values for that parameter); (2) for an out-tree, no such algorithm can exist unless one of the three parameters?origin node, destination node, and release time?is fixed; (3) For an in-tree, no such algorithm can exist unless one of the three parameters?origin node, destination node, and deadline ?is fixed; (4) for a bidirectional tree, no such algorithm can exist unless the origin node or the destination node is fixed; (5) for a bidirectional ring, no such algorithm can exist unless the origin node and either the destination node or the release time are fixed. Our results give a sharp boundary delineating those instances for which an optimal algorithm exists and those for which no such algorithm can exist.
A massively parallel multi-block hybrid compact-WENO scheme for compressible flows

A new multi-block hybrid compact-WENO finite-difference method for the massively parallel computation of compressible flows is presented. In contrast to earlier methods, our approach breaks the global dependence of compact methods by using explicit finite-difference methods at block interfaces and is fully conservative. The resulting method is fifth- and sixth-order accurate for the convective and diffusive fluxes, respectively. The impact of the explicit interface treatment on the stability and accuracy of the multi-block method is quantified for the advection and diffusion equations. Numerical errors increase slightly as the number of blocks is increased. It is also found that the maximum allowable time steps increase with the number of blocks. The method demonstrates excellent scalability on up to 1264 processors.
The transatlantic divide: Why are American and British IPE so different? ∗

An academic field of study may be said to exist when a coherent body of knowledge is constructed to define a subject of inquiry. Recognized standards come to be employed to train and certify specia...
Map of Witten's ★ to Moyal's ★

Abstract It is shown that Witten's star product in string field theory, defined as the overlap of half strings, is equivalent to the Moyal star product involving the relativistic phase space of even string modes. The string field ψ A ( x μ [ σ ]) can be rewritten as a phase space field of the even modes A ( x 2 n μ , x 0 , p 2 n μ ), where x 2 n μ are the positions of the even string modes, and p 2 n μ are related to the Fourier space of the odd modes x 2 n +1 μ up to a linear transformation. The p 2 n μ play the role of conjugate momenta for the even modes x 2 n μ under the string star product. The split string formalism is used in the intermediate steps to establish the map from Witten's ★-product to Moyal's ★-star product. An ambiguity related to the midpoint in the split string formalism is clarified by considering odd or even modding for the split string modes, and its effect in the Moyal star product formalism is discussed. The noncommutative geometry defined in this way is technically similar to the one that occurs in noncommutative field theory, but it includes the timelike components of the string modes, and is Lorentz invariant. This map could be useful to extend the computational methods and concepts from noncommutative field theory to string field theory and vice versa.
Tunneling electroresistance effect in ferroelectric tunnel junctions at the nanoscale.

Using a set of scanning probe microscopy techniques, we demonstrate the reproducible tunneling electroresistance effect on nanometer-thick epitaxial BaTiO3 single-crystalline thin films on SrRuO3 bottom electrodes. Correlation between ferroelectric and electronic transport properties is established by direct nanoscale visualization and control of polarization and tunneling current. The obtained results show a change in resistance by about 2 orders of magnitude upon polarization reversal on a lateral scale of 20 nm at room temperature. These results are promising for employing ferroelectric tunnel junctions in nonvolatile memory and logic devices.
Hormone replacement therapy for breast cancer survivors: Facts versus fears

The 'standard of practice' has been to prohibit breast cancer survivors from using hormone replacement therapy (HRT). However, in the last two decades there has been ever increasing evidence that postmenopausal ERT (oestrogen replacement therapy) protects against osteoporosis and ischaemic heart disease. This author believes firmly that a reappraisal of the 'standard of practice' is essential and long overdue. The search for a prospective randomized study addressing this critical issue has been difficult and, to date, fruitless. The practitioner must at present utilize indirect evidence in helping patients to make a decision on this very important aspect of health and wellness for breast cancer survivors. In 1896, Beatson [1] reported a clinical response in a premenopausal patient with metastatic breast cancer following oophorectomy. Multiple subsequent reports of hormonal manipulation, including adrenalectomy and the use of adjunctive hormones, have played a role in the treatment of advanced breast cancer since that time. However, the response to hormonal manipulation has been variable and at times confusing. Administration of oestrogens and progestins, as well as ablative procedures, have yielded responses in about 30% of unselected cases and in nearly 50% of patients with positive ERs (oestrogen receptors). Large studies have shown that, while the overall response rate for drugs such as tamoxifen, remains at 30%, this figure climbs to 75% if the oestrogen receptor value is greater than 100 fm/ mg of cytosol protein. These responses have a mean duration of 12 months, yet other patients show a similar response to additive hormone therapy. Conjugated oestrogens at high doses of 10 mg t.i.d, will produce a 30% clinical response rate in unselected postmenopausal patients with metastatic breast cancer. These responses also last approximately 12 months. In ER-positive patients, the response rate is 50%, similar to that seen in antioestrogen therapy. Some ER-negative tumours respond to hormonal manipulation as well as to tamoxifen therapy, suggesting another mode of action is operational in addition to binding at receptive sites, at least in some patients. In 1989, Wile and DiSaia [2] suggested that, in the absence of a prospective study of ERT in breast cancer survivors, one could analyse situations in which these patients were inadvertently exposed to high levels of oestrogen at times when they may have been harbouring breast cancer cells. These situations were defined as pregnancy coincident with breast cancer, pregnancy subsequent to breast cancer, breast cancer in both previous and current users of oral contraceptives (OCs), and breast cancer in postmenopausal women receiving ERT. Currently, approximately 185 000 cases of breast cancer occur in the United States annually. As 67% of these patients will survive this devastating disease to experience old age, we must address the advisability of HRT in this setting.
On gap equations and color-flavor locking in cold dense QCD with three massless flavors

Abstract The superconductivity in cold dense QCD with three massless flavors is analyzed in the framework of the Schwinger-Dyson equation. The set of two coupled gap equations for the color antitriplet, flavor antitriplet ( 3 , 3 ) and the color sextet, flavor sextet (6,6) order parameters is derived. It is shown that the antitriplet-antitriplet gives the dominant contribution to the color-flavor locked order parameter, while the sextet-sextet is small but nonzero.
ID: an intelligent information dictionary system

Abstract An information-oriented data dictionary describes the characteristics of the information represented in another (or “object”) database. Such description is different from that obtained by use of conventional data dictionary systems which produce primarily descriptions of the structural characteristics of the database. Information-oriented properties of data are related to the semantics of the database, i.e., the real world entities represented by data objects and their meaningful properties ( as defined by the database developer). This paper also presents a conceptual design approach and a database architecture for ID, an intelligent information-oriented dictionary system. This architecture is presented in terms of ER model constructs.
Influence of a fat layer on the near infrared spectra of human muscle: quantitative analysis based on two-layered Monte Carlo simulations and phantom experiments

The influence of fat thickness on the diffuse reflectance spectra of muscle in the near infrared (NIR) region is studied by Monte Carlo simulations of a two-layer structure and with phantom experiments. A polynomial relationship was established between the fat thickness and the detected diffuse reflectance. The influence of a range of optical coefficients (absorption and reduced scattering) for fat and muscle over the known range of human physiological values was also investigated. Subject-to-subject variation in the fat optical coefficients and thickness can be ignored if the fat thickness is less than 5 mm. A method was proposed to correct the fat thickness influence.
Firm Size, University Based Research, and the Returns to R & D

This paper compares university-based research relationships between small and large firms as an explanation for the difference in innovative activity across firm sizes. We test the hypothesis that there are diseconomies of scale in producing innovations in large firms due to the inherent bureaucratization process which inhibits both innovative activity as well as the speed with which new inventions move through the corporate system towards the market. By utilizing university-based research relationships, small firms are able to avoid bureaucratic inefficiencies.
The role of the TRAF2/3 binding site in LMP1 and CD40 signaling

The Epstein-Barr virus encoded protein, LMP1, is a viral mimic of the cellular protein CD40. In comparison to CD40, LMP1 signals to B lymphocytes in an amplified and sustained manner. LMP1 signaling is thought to contribute to the development of lymphoma in patients afflicted with HIV or in transplant recipients who are immunosuppressed. CD40 uses TRAF2 as a positive mediator of its signaling, while TRAF3 serves as a negative regulator. Interestingly, LMP1 uses TRAF3 as a positive mediator of its signaling. CD40, not LMP1, signaling has been shown to degrade TRAF2 and 3. Currently, lack of LMP1-induced TRAF degradation is thought to result in exaggerated LMP1 signals. Because LMP1 binds TRAF2 with less affinity than CD40 and TRAF2 is needed for inducing CD40-mediated TRAF2 and 3 degradation, it was thought that relative affinity for TRAF2 controls the disparate ways in which CD40 and LMP1 use and degrade TRAFs 2 and 3, and that this in turn results from the different sequences of the TRAF2/3 binding sites of the two receptors. However, our recent studies reveal that TRAF binding affinity and TRAF binding site sequence only partially dictates CD40 versus LMP1 signaling properties. We have been studying signaling via hybrid molecules that have had their TRAF binding sites switched so that CD40 contains the TRAF binding site of LMP1 and LMP1 contains the CD40 TRAF binding site. Examination of TRAF binding and degradation, cytokine production, IgM secretion, and the activation of c-Jun kinase and NF-kB revealed that some events are strongly dictated by TRAF binding site sequences, others partially regulated, and still others appear independent of TRAFs 2 and 3.