cssi/SciSciGPT-SciSciNet huggingface dataset:
The Evolution of Massive Stars. I. Red Supergiants in the Magellanic Clouds

We investigate the red supergiant (RSG) content of the SMC and LMC using multiobject spectroscopy on a sample of red stars previously identified by BVR CCD photometry. We obtained high-accuracy (<1 km s-1) radial velocities for 118 red stars seen toward the SMC and 167 red stars seen toward the LMC, confirming most of these (89% and 95%, respectively) as red supergiants. Spectral types were also determined for most of these RSGs. We find that the distribution of spectral types is skewed toward earlier type at lower metallicities: the average (median) spectral type is K5–K7 I in the SMC, M1 I in the LMC, and M2 I in the Milky Way. Our examination of the Kurucz ATLAS9 model atmospheres suggests that the effect that metallicity has on the appearance on the TiO lines is probably sufficient to account for this effect, and we argue that RSGs in the Magellanic Clouds are 100 K (LMC) and 300 K (SMC) cooler than Galactic stars of the same spectral types. The colors of the Kurucz models are not consistent with this interpretation for the SMC, although other models (e.g., Bessell et al.) show good agreement. A finer grid of higher resolution synthetic spectra appropriate to cool supergiants is needed to better determine the effective temperature scale. We compare the distribution of RSGs in the H-R diagram to that of various stellar evolutionary models; we find that none of the models produce RSGs as cool and luminous as what is actually observed. This result is much larger than any uncertainty in the effective temperature scale. We note that, were we to simply adopt the uncorrected Galactic effective scale for RSGs and apply this to our sample, then the SMC's RSGs would be underluminous compared with the LMC's, contrary to what we expect from stellar evolution considerations. In all of our H-R diagrams, however, there is an elegant sequence of decreasing effective temperatures with increasing luminosities; explaining this will be an important test of future stellar evolutionary models. Finally, we compute the blue-to-red supergiant ratio in the SMC and LMC, finding that the values are indistinguishable (~15) for the two Clouds. We emphasize that "observed" B/R values must be carefully determined if a comparison with that predicted by stellar models is to be meaningful. The nonrotation Geneva models overestimate the number of blue to red supergiants for the SMC, but underestimate it for the LMC; however, given the inability to produce high-luminosity RSGs in the models that match what is observed in the H-R diagram, such a disagreement is not surprising.
Quantum spatial propagation of squeezed light in a degenerate parametric amplifier

Abstract Differential equations which describe the steady state spatial evolution of nonclassical light are established using standard quantum field theoretic techniques. A Schrodinger equation for the state vector of the optical field is derived using the quantum analog of the slowly varying envelope approximation (SVEA). The steady state solutions are those that satisfy the time independent Schrodinger equation. The resulting eigenvalue problem then leads to the spatial propagation equations. For the degenerate parametric amplifier this method shows that the squeezed state is an eigenstate of the squeezing hamiltonian. The magnitude and phase of the squeezing parameter obey nonlinear differential equations coupled by the amplifier gain constant and phase mismatch. The solution to these differential equations is equivalent to one obtained from the classical three-wave mixing steady state solution to the parametric amplifier with a nondepleted pump.
Propane Oxidation over Platinum Supported on Zirconia

Abstract Propane oxidation activity over Pt/zirconia was studied as a function of metal concentration, metal surface area, and temperature. The catalysts, prepared by multiple impregnation of zirconia with chloroplatinic acid, ranged in concentration from 0.02 to 1.5 wt% Pt. A recirculation batch reactor was used for the activity experiments. At a fixed amount of Pt (4 mg), the oxidation rate decreased by a factor of 20 with increasing metal concentration. When calculated per Pt surface atom, as determined by CO chemisorption, the specific oxidation rate initially decreased and then reached a constant value at concentrations above 0.10 wt% Pt. The apparent activation energy remained constant at 17.8 ± 3.5 kcal/mol with Pt concentration. To evaluate the effect of support material, the data were compared to an analogous study in our laboratory over Pt/γ-alumina. Over highly dispersed platinum, propane oxidation activity was two orders of magnitude faster over Pt/zirconla as compared to Pt/γ-alumina. The activity change reflects a difference in interaction between support and catalytic metal. At higher Pt concentrations the influence of the support vanishes and the rate constants on both supports are the same, as expected. At lower Pt concentrations. metal redispersion occurs readily in oxygen at 500°C on γ-alumina, but not on zirconia, according to observed changes in propane oxidation rate.
U.S. Department of Energy's Solid Oxide Fuel Cells: Technical Advances

The U.S. Department of Energy's (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industries, is leading the development and demonstration of high-efficiency solid oxide fuel cells (SOFCs) and fuel cell turbine hybrid power generation systems for distributed generation (DG) markets. The DOE FE DG program has three aspects: the Solid State Energy Conversion Alliance (SECA), Central Power Systems, and the High Temperature Electrochemistry Center (HiTEC). NETL is partnering with Pacific Northwest National Laboratory in developing new directions in research under SECA for the development and commercialization of modular, low-cost, and fuel-flexible SOFC systems. The SECA initiative, through advanced materials, processing, and system integration research and development (R&D) will bring the fuel cell cost to $400 per kilowatt (kW) by 2010 for stationary and auxiliary power unit markets. The SECA program is currently structured to include six competing industry teams supported by a crosscutting core technology program. DOE is ultimately concerned with coal-based central power plants. Advanced aspects of solid oxide technology are part of HiTEC R&D.
On the worldsheet formulation of the six-dimensional self-dual string

Abstract Despite recent evidence indicating the existence of a new self-dual six-dimensional superstring, no satisfactory worldsheet formulation of such a string has been proposed. In this note we show that a theory built from Z 4 parafermions may have the right properties to describe the light-cone conformal field theory of this string. This indicates a possible worldsheet formulation of this theory.
Efficient partitioning for the batch-fabricated fourth generation computer

The computer industry is on the verge of an upheaval, due to drastically new hardware and modern computational concepts. Read-only memories which operate near 0.1 microseconds are available, while large-scale integration (LSI) offers the promise of inexpensive, batch fabricated processing of logic and storage elements. The problem which confronts the computer designer is how to use these elements in an efficient manner to take full advantage of their speed and flexibility. Many approaches have been proposed, but none have shown a clear solution to the problem. The concept presented in this paper is the result of extensive development activities.
Simultaneous Nitrogen Doping and Reduction of Graphene Oxide

We developed a simple chemical method to obtain bulk quantities of N-doped, reduced graphene oxide (GO) sheets through thermal annealing of GO in ammonia. X-ray photoelectron spectroscopy (XPS) study of GO sheets annealed at various reaction temperatures reveals that N-doping occurs at a temperature as low as 300 °C, while the highest doping level of ∼5% N is achieved at 500 °C. N-doping is accompanied by the reduction of GO with decreases in oxygen levels from ∼28% in as-made GO down to ∼2% in 1100 °C NH3 reacted GO. XPS analysis of the N binding configurations of doped GO finds pyridinic N in the doped samples, with increased quaternary N (N that replaced the carbon atoms in the graphene plane) in GO annealed at higher temperatures (≥900 °C). Oxygen groups in GO were found responsible for reactions with NH3 and C−N bond formation. Prereduced GO with fewer oxygen groups by thermal annealing in H2 exhibits greatly reduced reactivity with NH3 and a lower N-doping level. Electrical measurements of individua...
Annuli in generalized Heegaard splittings and degeneration of tunnel number

Abstract. We analyze how a family of essential annuli in a compact 3-manifold will induce, from a strongly irreducible generalized Heegaard splitting of the ambient manifold, generalized Heegaard splittings of the complementary components. There are specific applications to the subadditivity of tunnel number of knots, improving somewhat bounds of Kowng [Kw]. For example, in the absence of 2-bridge summands, the tunnel number of the sum of n knots is no less than $\frac{2}{5}$ the sum of the tunnel numbers.
Aspects of N = 1 type I-heterotic duality in four dimensions

Abstract In this paper we discuss some aspects of N = 1 type I-heterotic string duality in four dimensions. We consider a particular example of a (weak-weak) dual pair where on the type I side there are only D9-branes corresponding to the perturbative heterotic description in a certain region of the moduli space. We match the perturbative type I and heterotic tree-level massless spectra by giving certain scalars appropriate vevs, and point out the crucial role of the perturbative superpotential (on the heterotic side) for this matching. We also discuss the role of anomalous U (1) gauge symmetry present in both type I and heterotic models. In the perturbative regime we match the (tree-level) moduli spaces of these models. Since both type I and heterotic models can be treated perturbatively, we are able to discuss a dictionary that in generic models maps the type I description onto the heterotic one, and vice versa. Finally, we discuss possible directions to study perturbative quantum corrections to the moduli space, as well as outline ways to learn about the non-perturbative effects in both descriptions.
Theory at quark matter '02

Abstract I summarize theory at Quark Matter '02, stressing the continuing inability model to describe all notable features of the data from √ s /A: 55 → 200GeV
Characterization and reactivity of some electrochemically generated products of Rh2(μ-dppp)2(μ-CO)Cl2 (dppp = 2-(diphenylphosphino)pyridine)

Abstract The reaction of the dirhodium(I) complex Rh 2 (μ-dppp) 2 (μ-CO)Cl 2 , 1 , (dppp = 2- (diphenylphosphino)pyridine) with Cl − in the presence of CO leads to the monomeric species Rh(dppp) 2 (CO)Cl and Rh(CO) 2 Cl − 2 . In the absence of CO no chemical reaction occurs. Electrochemical oxidation of 1 in the presence of Cl − at + 0.90 V (vs SCE) affords a new dirhodium(II) complex Rh 2 (μ-dppp) 2 (CO)Cl 4 , 4 , whose fluxional behaviour at room temperature is demonstrated using variable temperature 31 P NMR. The 31 P NMR is interpreted with the aid of the complex containing 13 CO. Complex 4 reacts with CO to produce Rh 2 (μ-dppp) 2 (CO) 2 Cl 4 , 5 , and with (CH 3 ) 3 CNC ( t -BuNC) to form Rh 2 (μ-dppp) 2 ( t -BuNC) 2 Cl 4 , 6 . Complex 6 appears to partially dissociate to give [Rh 2 (μ-dppp) 2 (μ-Cl) ( t -BuNC) 2 Cl 2 ]Cl. When the equilibrium mixture is treated with NH 4 PF 6 the equilibrium is driven in the direction of the ionic species and the complex [Rh 2 (μ-dppp) 2 (μ-Cl) ( t -BuNC) 2 Cl 2 ]PF 6 is isolated.
The facsimile camera - Its potential as a planetary lander imaging system

Review of the performance characteristics of the facsimile camera, emphasizing its line-scan sampling process; the design tradeoffs which are imposed by planetary lander missions, emphasizing those tradeoffs which define the Viking Lander Camera parameters; and new concepts which are currently being investigated for future planetary lander missions, emphasizing an integrated imagery and spectrometry concept.
Energy efficient housing stimulus that pays for itself

Abstract This paper describes an energy-efficient housing stimulus strategy that can: (1) quickly provide large-scale job creation; (2) reduce home energy bills by 30–50% with associated reductions in emissions and energy assistance spending; (3) stabilize home values and reduce foreclosure inventory; (4) help to eliminate childhood lead poisoning; and (5) implement regulatory reforms that highlight market incentives for cost effective energy efficiency and alternative home energy investments. These benefits, far in excess of costs, can be achieved by combining “lead-safe window replacement” with other weatherization activities and simple regulatory and market reforms. This strategy can help to coordinate American Recovery and Reinvestment Act funding for energy efficiency, the $75 billion Making Home Affordable plan to reduce foreclosures, and the recently announced partnership between the Departments of Energy (DOE) and Housing and Urban Development (HUD) to streamline weatherization efforts and spur job creation.
Maximum likelihood method for cross-correlations with astrophysical sources

We generalize the maximum likelihood-type method used to study cross-correlations between a catalog of candidate astrophysical sources and ultrahigh energy cosmic rays (UHECRs), to allow for differing source luminosities. The new method is applicable to any sparse dataset such as UHE gamma rays or astrophysical neutrinos. Performance of the original and generalized techniques is evaluated in simulations of various scenarios. Applying the new technique to data, we find an excess correlation of about nine events between HiRes UHECRs and known BLLacs, with a 6 × 10−5 probability of such a correlation arising by chance.
Canonical Sasakian Metrics

Let M be a closed manifold of Sasaki type. A polarization of M is defined by a Reeb vector field, and for any such polarization, we consider the set of all Sasakian metrics compatible with it. On this space we study the functional given by the square of the L 2-norm of the scalar curvature. We prove that its critical points, or canonical representatives of the polarization, are Sasakian metrics that are transversally extremal. We define a Sasaki-Futaki invariant of the polarization, and show that it obstructs the existence of constant scalar curvature representatives. For a fixed CR structure of Sasaki type, we define the Sasaki cone of structures compatible with this underlying CR structure, and prove that the set of polarizations in it that admit a canonical representative is open. We use our results to describe fully the case of the sphere with its standard CR structure, showing that each element of its Sasaki cone can be represented by a canonical metric; we compute their Sasaki-Futaki invariant, and use it to describe the canonical metrics that have constant scalar curvature, and to prove that only the standard polarization can be represented by a Sasaki-Einstein metric.
The Star Formation Epoch of the Most Massive Early-Type Galaxies

We present new spatially resolved Keck spectroscopy of early-type galaxies in three galaxy clusters at z ≈ 0.5. We focus on the fundamental plane (FP) relation and combine the kinematics with structural parameters determined from HST images. The galaxies obey clear FP relations, which are offset from the FP of the nearby Coma Cluster due to passive evolution of the stellar populations. The z ≈ 0.5 data are combined with published data for 11 additional clusters at 0.18 ≤ z ≤ 1.28, to determine the evolution of the mean M/L_B ratio of cluster galaxies with masses M ≳ 10^(11) M_☉, as implied by the FP. We find d log(M/L_B)/dz = -0.555 ± 0.042, stronger evolution than was previously inferred from smaller samples. The observed evolution depends on the luminosity-weighted mean age of the stars in the galaxies, the IMF, selection effects due to progenitor bias, and other parameters. Assuming a normal IMF but allowing for various other sources of uncertainty, we find z_* = 2.01^(+0.22)_(-0.17) for the luminosity-weighted mean star formation epoch. The main uncertainty is the slope of the IMF in the range 1-2 M_☉: we find z_* = 4.0 for a top-heavy IMF with slope x = 0. The M/L_B ratios of the cluster galaxies are compared to those of field early-type galaxies at 0.32 ≤ z ≤ 1.14. Assuming that progenitor bias and the IMF do not depend on environment, we find that the present-day age of stars in massive field galaxies is 4.1% ± 2.0% (≈0.4 Gyr) less than that of stars in massive cluster galaxies. This relatively small age difference is surprising in the context of expectations from "standard" hierarchical galaxy formation models and provides a constraint on the physical processes that are responsible for halting star formation in the progenitors of today's most massive galaxies.
Finding a jewel: Identity and gendered space in Islamic finance:

In this article, I explore how globalization discourses practices work together to form the identities of female Islamic bankers working in the first stand-alone women’s Islamic bank in Dubai, United Arab Emirates. An Islamic bank interacts with the individual by providing a discursive and physical space in which the subject can shape and respond to her desire to identify and engage with the debates in the global Muslim community about morality, practice and the role of Islam in everyday life. Global financial systems and local gender practices are embodied in these buildings in a kind of financial purdah: building spaces become both a marketing tool and a support for globally-based economic activity under the auspices of morality and tradition. Based upon fieldwork and interviews with Islamic bankers, I show how normative global financial practices and local moral gender practices work together for the advancement of both.
Trivalent and divalent chromium ions in spinels

Abstract Phase relations in the ternary system MgO-Al2O3-Cr2O3 were determined at 1700 ± 15°C to delineate the stability field of spinel crystalline solutions. It was found that there is no solubility of Cr2O3 in MgCr2O4 spinel, and this is attributed to the high octahedral field stabilization energy for Cr3+ ion. By heating mixtures consisting of MgO and 50–66 mole % Cr2O3 in a reducing atmosphere at 1800–2000°C a new spinel-type crystalline solution was obtained having the general formula, (Mg8−xCrx2+)IV Cr163+VIO32. Data are presented concerning the synthesis, structure, electronic spectra and magnetic susceptibility of these crystalline solutions.
Gamma-Ray Burst Peak Duration as a Function of Energy

Gamma-ray burst time histories often consist of many peaks. These peaks tend to be narrower at higher energy. If gamma-ray bursts are cosmological, the energy dependence of gamma-ray burst timescales must be understood in order to correct the timescale dependence due to the expansion of the universe. By using the average autocorrelation function and the average pulse width, we show that the narrowing with energy follows, quite well, a power law. The power-law index is ~-0.4. This is the first quantitative relationship between temporal and spectral structure in gamma-ray bursts. It is unclear what physics causes this relationship. The average autocorrelation has a universal shape such that one energy range scales linearly with time into all other energy ranges. This shape is approximately the sum of two exponentials.
Entropy theory for sofic groupoids I: The foundations

This is the first part in a series in which sofic entropy theory is generalized to class-bijective extensions of sofic groupoids. Here we define topological and measure entropy and prove invariance. We also establish the variational principle, compute the entropy of Bernoulli shift actions and answer a question of Benjy Weiss pertaining to the isomorphism problem for non-free Bernoulli shifts. The proofs are independent of previous literature.
Dynamic PL&T using Two Reference Nodes Equipped with Steered Directional Antenna for Significant PL&T Accuracy

Dynamic Position Location and Tracking PL&T is proposed deploying the integrated approach of zone finding and triangulation using two friendly nodes equipped with Steered Directional Antenna DA in Mobile Ad hoc Networks MANET. This approach allows the system to use only two references instead of a typical 3 references for a straight triangulation. Moreover, the performance of the proposed algorithm with references using directional antennas shows significant improvement over triangulation using references with Omni-directional antennas as the beam power is concentrated. However, dynamic switching of reference nodes is frequently required as the target moves outside the predicted zone. This paper presents a better tracking accuracy in using proposed dynamic PL&T as compared to other PL&T techniques. The multipath fading is also addressed with the use of KV transform coding technique which uses forward error correction and sample interleaving achieves greater than 90% tracking accuracy with BERs of 10-6 or better.
Reflection groups in algebraic geometry

After a brief exposition of the theory of discrete reflection groups in spherical, euclidean and hyperbolic geometry as well as their analogs in complex spaces, we present a survey of appearances of these groups in various areas of algebraic geometry.
Dark-matter detector, novel light counter, and the ICARUS project

We describe the current status of the development of imaging electron drift Liquid Argon Detectors (ICARUS) and the development of the Visible Light Photon Counter (VLPC) for scintillating fiber tracking for (SPC) SSC/LHC detectors. We then propose a detector that combines these two techniques to detect massive WIMPs through the possible identified Xe recoil in a liquid Xenon detector.
Vibration Delocalization of Nearly Periodic Structures Using Coupled Piezoelectric Networks

It is known that, when the mechanical coupling between the substructures is weak, small imperfections in a periodic structure can induce vibration localization. This phenomenon could lead to large vibration in certain regions of the structure and could be very harmful to the system. In this study, it is shown that the proposed coupled piezoelectric circuits can greatly relieve or even eliminate such localization problems. Part of the structural vibration energy will be transferred into electrical energy through the piezoelectric materials, and the newly created electro-mechanical wave/energy channel will sustain the energy propagation throughout the structure. The effectiveness and robustness of the coupled piezoelectric circuits on reducing vibration localization is demonstrated through analysis. Design guidelines are also established via approximation techniques and parametric studies.
(Semi-)Riemannian geometry of (para-)octonionic projective planes

Abstract We use reduced homogeneous coordinates to construct and study the (semi-)Riemannian geometry of the octonionic (or Cayley) projective plane O P 2 , the octonionic projective plane of indefinite signature O P ( 1 , 1 ) , the para-octonionic (or split octonionic) projective plane O ′ P 2 and the hyperbolic dual of the octonionic projective plane O H 2 . We also show that our manifolds are isometric to the (para-)octonionic projective planes defined classically by quotients of Lie groups.
Molecular similarity for small species: refining the isoelectronic index.

This paper tests a chemical-similarity model against properties of gas-phase neutral triatomic and four-atom molecules. The model is a variant of the Diatomics-in-Molecules (DIM) picture, which considers a molecule to be the superposition of all diatomic molecules that could be formed from adjacent atoms in the molecule. The variant is that adjacent atoms are counted as a diatomic molecule only if they are bonded. The tests consist of investigating whether molecules with the same number of electrons, computed by the adjacent-DIM model, have data more similar than do molecules selected at random. The tests vindicate the model for the heat of atomization and for the equilibrium constant for formation, they agree with the model with lesser confidence for the entropy and the partition function, and they show that the model fails for the ionization potential. The model applies with most confidence to molecules with the more electronegative atoms from rows 2 or 3 (those of greatest interest in organic chemistry...
Can Synthetic Validity Methods Achieve Discriminant Validity

Our focus is on the difficulties that synthetic validity encounters in attempting to achieve discriminant validity and the implications of these difficulties. Johnson et al. (2010) acknowledge the potential problems involved in attaining discriminant validity in synthetic validity. For example, they report that Peterson et al. (2001), Johnson (2007), and other synthetic validity studies report failure to achieve discriminant validity. What this failure means is that a synthetic validity equation developed to predict validity for Job A does as well in predicting validity for Jobs B, C, D, and so forth as it does for Job A. Johnson et al. then go on to propose that this problem might be overcome by careful attention to both the criterion and predictor sides of synthetic validity. We question whether their proposals can be made to work.
DbAccess: interactive statistics and graphics for plasma physics databases

DbAccess is an X-windows application, written in IDL{reg_sign}, meeting many specialized statistical and graphical needs of NSTX [National Spherical Torus Experiment] plasma physicists, such as regression statistics and the analysis of variance. Flexible ''views'' and ''joins,'' which include options for complex SQL expressions, facilitate mixing data from different database tables. General Atomics Plot Objects add extensive graphical and interactive capabilities. An example is included for plasma confinement-time scaling analysis using a multiple linear regression least-squares power fit.
Conversion of Azides into Diazo Compounds in Water

Diazo compounds are in widespread use in synthetic organic chemistry but have untapped potential in chemical biology. We report on the design and optimization of a phosphinoester that mediates the efficient conversion of azides into diazo compounds in phosphate buffer at neutral pH and room temperature. High yields are maintained in the presence of common nucleophilic or electrophilic functional groups, and reaction progress can be monitored by colorimetry. As azido groups are easy to install and maintain in biopolymers or their ligands, this new mode of azide reactivity could have substantial utility in chemical biology.
Is the World at the Border of Chaos

Dissipative dynamical systems with many degrees of freedom naturally evolve to a self‐organized critical state with fluctuations (avalanches) extending over all length‐ and time‐scales. The systems operate at the border of chaos, with zero Lyapunov exponent and algebraic growth of initial deviations. This picture has support from numerical and analytical model calculations, and from experiments by Held on sandpiles, by Babcock and Westervelt, and by Che and Suhl on magnetic domain patterns, and by God on earthquakes. Applications to turbulence, biology, and economics have been suggested.
New IR dualities in supersymmetric gauge theory in three dimensions

We present nontrivial examples of d = 3 gauge theories with sixteen and eight supercharges which are infrared dual at special points in the moduli space. This duality is distinct from mirror symmetry. To demonstrate duality we construct the gauge theories of interest using D2-branes and orientifolds and then consider their lift to M-theory. We also discuss the strong coupling limit of orientifold two-planes and orbifolds of orientifold six-planes.
Oscillatory Flow Between Two Hemispheres for Shearing Protein Solution

Protein aggregation, one of the common molecular mechanisms for neurodegenerative diseases, is affected by variety of physical factors, one of which is shear rate of protein solution. This paper provides theoretical background on the shear rate in the experimental system we have proposed to effectively apply and control shear. We carried out the mathematical analysis of the flow field resulted from torsional or transverse oscillation on the outer boundary between two concentric hemispheres by perturbation method. We have obtained analytical solutions for the velocity field, the shear rate, and the flow pattern of steady streaming created by the nonlinear interaction of the oscillatory flow.
The anapole form factor of the deuteron

Abstract We find the leading-order result for the anapole form factor of the deuteron using effective field theory. The momentum dependence of the anapole form factor is different from that of the matrix element of the strange currents in the deuteron, which may provide a way for disentangling these two competing effects when analyzing parity-violating electron–deuteron scattering experiments. We give closed form expressions for both the form factor and integrals often encountered in the NN effective field theory.
Variability of research performance across disciplines within universities in non-competitive higher education systems

Many nations are adopting higher education strategies that emphasize the development of elite universities able to compete at the international level in the attraction of skills and resources. Elite universities pursue excellence in all their disciplines and fields of action. The impression is that this does not occur in "non-competitive" education systems, and that instead, within single universities excellent disciplines will coexist with mediocre ones. To test this, the authors measure research productivity in the hard sciences for all Italian universities over the period 2004---2008 at the levels of the institution, their individual disciplines and fields within them. The results show that the distribution of excellent disciplines is not concentrated in a few universities: top universities show disciplines and fields that are often mediocre, while generally mediocre universities will often include top disciplines.
EFFECT OF PHOTOOXIDATION ON MOLECULAR WEIGHT DISTRIBUTIONS OF CORBETT ASPHALT FRACTIONS BY GEL PERMEATION CHROMATOGRAPHY

ABSTRACT Oxidation of asphalt is believed to be one of the major contributing factors to the failure of asphalt pavement. Due to molecular complexity, the oxidation mechanism of asphalt is complicated by interactions among the molecules of different types. To minimize the interactions, the asphalt sample was separated into saturates, naphthalene aromatics, polar aromatics, and asphaltenes. These Corbett fractions were then oxidized under ultraviolet irradiation. Gel permeation chromatography was used to analyze the molecular weight changes of the Corbett fractions during photooxidation. All Corbett fractions have shown significant increase in molecular weight. The oxidized saturates have the highest weight average molecular weight and the most complicated molecular size profiles among the oxidized Corbett fractions
High precision simulations of the longest common subsequence problem

The longest common subsequence problem is a long studied prototype of pattern matching problems. In spite of the effort dedicated to it, the numerical value of its central quantity, the Chvatal-Sankoff constant, is not yet known. Numerical estimations of this constant are very difficult due to finite size effects. We propose a numerical method to estimate the Chvatal-Sankoff constant which combines the advantages of an analytically known functional form of the finite size effects with an efficient multi-spin coding scheme. This method yields very high precision estimates of the Chvatal-Sankoff constant. Our results correct earlier estimates for small alphabet size while they are consistent with (albeit more precise than) earlier results for larger alphabet size.
Microbial habitability of the Hadean Earth during the late heavy bombardment

Between about 4.1 and 3.8 billion years ago, conditions on Earth might be expected to have been pretty extreme. Data from lunar crust samples, meteorites and other Solar System materials all point to this as a time — known as the late heavy bombardment — when the Earth and other inner planets were subjected to cataclysmic impact events. Habitats on the early Earth would have almost certainly been repeatedly destroyed, prompting suggestions that life might not have survived. In fact the thermal effects of this bombardment on the young Earth have remained poorly constrained, leaving the field leaving the field a fertile one for speculation. Now Oleg Abramov and Stephen Mojzsis report results from computer models constructed to study the thermal effects of impacts on the terrestrial lithosphere during the late heavy bombardment. They find no plausible scenario in which Earth's habitable zone was fully sterilized, and conclude that the evidence from ribosomal RNA ancestry that terrestrial life arose from thermophiles or hyperthermophiles is consistent with the prevalence of hydrothermal activity suggested by the model. Diverse Solar System materials indicate that a cataclysmic spike occurred in the number of impacts within the inner Solar System about 3.9 billion years ago. Here, numerical models probe the degree of thermal metamorphism there would have been during this period in the Earth's crust, and thus how habitable the near- and subsurface would have been for microbes; analysis shows no plausible scenario in which the habitable zone was fully sterilized. Lunar rocks1,2 and impact melts3, lunar4 and asteroidal meteorites5, and an ancient martian meteorite6 record thermal metamorphic events with ages that group around and/or do not exceed 3.9 Gyr. That such a diverse suite of solar system materials share this feature is interpreted to be the result of a post-primary-accretion cataclysmic spike in the number of impacts commonly referred to as the late heavy bombardment (LHB)1,2,3,4,5,6,7. Despite its obvious significance to the preservation of crust and the survivability of an emergent biosphere, the thermal effects of this bombardment on the young Earth remain poorly constrained. Here we report numerical models constructed to probe the degree of thermal metamorphism in the crust in the effort to recreate the effect of the LHB on the Earth as a whole; outputs were used to assess habitable volumes of crust for a possible near-surface and subsurface primordial microbial biosphere. Our analysis shows that there is no plausible situation in which the habitable zone was fully sterilized on Earth, at least since the termination of primary accretion of the planets and the postulated impact origin of the Moon. Our results explain the root location of hyperthermophilic bacteria in the phylogenetic tree for 16S small-subunit ribosomal RNA8, and bode well for the persistence of microbial biospheres even on planetary bodies strongly reworked by impacts.
The shapes of molecular cloud cores in Orion

We investigate the intrinsic shapes of starless cores in the Orion giant molecular cloud, using the pre-stellar core sample of Nutter & Ward-Thompson, which is based on submillimetre SCUBA data. We employ a maximum-likelihood method to reconstruct the intrinsic distribution of ellipsoid axial ratios from observations of the axial ratios of projected plane-of-the-sky core ellipses. We find that, independently of the details of the assumed functional form of the distribution, there is a strong preference for oblate cores of finite thickness. Cores with varying finite degrees of triaxiality are a better fit than purely axisymmetric cores, although cores close to axisymmetry are not excluded by the data. The incidence of prolate starless cores in Orion is found to be very infrequent. We also test the consistency of the observed data with a uniform distribution of intrinsic shapes, where oblate and prolate cores of all degrees of triaxiality occur with equal probability. Such a distribution is excluded at the 0.1 per cent level. These findings have important implications for theories of core formation within molecular clouds.
Carbon fibre-cement adhesion in carbon fibre reinforced cement composites

Abstract The addition of small amounts of short carbon fibres to cement causes a great increase in the composite material toughness and tensile, flexural, and impact strength. In order to understand how cement properties are improved by carbon fibres and to understand the level of adhesion and interfacial failure mode which are necessary to obtain optimum carbon fibre reinforced cement (CFRC) properties, various admixtures were included in cement and CFRC. Their effects on the carbon fibre-cement adhesion and the composite material properties were determined using fibre pull-out and composite material flexural tests. The addition of latex to CFRC, and hot water curing of CFRC dramatically increase fibre-matrix adhesion. Both latex (with an anti-foam agent) and hot water curing increase flexural strength by 40% over normal CFRC, and latex increases toughness 100%. Alteration of fibre-matrix adhesion changes the failure mode from fibre pull-out to fibre rupture. Optimum strength and toughness of CFRC result from an intermediate level of fibre-matrix adhesion.
Selfish Load Balancing and Atomic Congestion Games

We revisit a classical load balancing problem in the modern context of decentralized systems and self-interested clients. In particular, there is a set of clients, each of whom must choose a server from a permissible set. Each client has a unit-length job and selfishly wants to minimize its own latency (job completion time). A server's latency is inversely proportional to its speed, but it grows linearly with (or, more generally, as the pth power of) the number of clients matched to it. This interaction is naturally modeled as an atomic congestion game, which we call selfish load balancing. We analyze the Nash equilibria of this game and prove nearly tight bounds on the price of anarchy (worst-case ratio between a Nash solution and the social optimum). In particular, for linear latency functions, we show that if the server speeds are relatively bounded and the number of clients is large compared with the number of servers, then every Nash assignment approaches social optimum. Without any assumptions on the number of clients, servers, and server speeds, the price of anarchy is at most 2.5. If all servers have the same speed, then the price of anarchy further improves to $1 + 2/\sqrt{3} \approx 2.15.$ We also exhibit a lower bound of 2.01. Our proof techniques can also be adapted for the coordinated load balancing problem under L2 norm, where it slightly improves the best previously known upper bound on the competitive ratio of a simple greedy scheme.
Theoretical Parameter Study of Aerodynamic Vectoring Particle Sorting

A new particle sorting technique called aerodynamic vectoring particle sorting (AVPS) has recently been shown to be effective at sorting particles without particles contacting surfaces. The technique relies on turning a free jet sharply without extended control surfaces. The flow turning results in a balance of particle inertia and several forces (pressure, drag, added mass, and body forces) that depend on particle size and density. The present paper describes a theoretical study of particle sorting in a turning flow. The purpose of this study is to extend AVPS to parameter spaces other than those that are currently under investigation. Spherical particles are introduced into a turning flow in which the velocity magnitude increases like r. The trajectory of each particle is calculated using the particle equation of motion with drag laws that are appropriate for various Knudsen number regimes. Large data sets can be collected rapidly for various particle sizes, densities, turning radii, flow speeds, and fluid properties. Ranges of particle sizes that can be sorted are determined by finding an upper bound (where particles move in a straight line) and a lower bound (where particles follow flow streamlines). It is found that the size range of particles that can be sorted is larger for smaller turning radii, and that the range moves toward smaller particles as the flow speed and the particle-to-fluid density ratio are increased. Since this flow is laminar and 2-D, and particle loading effects are ignored, the results represent a "best case" scenario.
On the coexistence of macrocell spatial multiplexing and cognitive femtocells

We study a two-tier macrocell/femtocell system where the macrocell base station is equipped with multiple antennas and makes use of multiuser MIMO (spatial multiplexing), and the femtocells are “cognitive”. In particular, we assume that the femtocells are aware of the locations of scheduled macrocell users on every time-frequency slot, so that they can make decisions on their transmission opportunities accordingly. Femtocell base stations are also equipped with multiple antennas. We propose a scheme where the macrocell downlink (macro-DL) is aligned with the femtocells uplink (femto-UL) and, Vice Versa, the macrocell uplink (macro-UL) is aligned with the femtocells downlink (femto-DL). Using a simple “interference temperature” power control in the macro-DL/femto-UL direction, and exploiting uplink/downlink duality and the Yates, Foschini and Miljanic distributed power control algorithm in the macro-UL/femto-DL direction, we can achieve an extremely attractive macro/femto throughput tradeoff region in both directions. We investigate the impact of multiuser MIMO spatial multiplexing in the macrocell under the proposed scheme, and find that large gains are achievable by letting the macrocell schedule groups of co-located users, such that the number of femtocells affected by the interference temperature power constraint is small.
Atomic Hydrogen and Star Formation in the Bridge/Ring Interacting Galaxy Pair NGC 7714/7715 (Arp 284)

We present high spatial resolution 21 cm H I maps of the interacting galaxy pair NGC 7714/7715. We detect a massive (2 × 109 M☉) H I bridge connecting the galaxies that is parallel to but offset from the stellar bridge. A chain of H II regions traces the gaseous bridge, with Hα peaks near but not on the H I maxima. An H I tidal tail is also detected to the east of the smaller galaxy NGC 7715, similarly offset from a stellar tail. The strong partial stellar ring on the east side of NGC 7714 has no H I counterpart, but on the opposite side of NGC 7714 there is a 109 M☉ H I loop ~11 kpc in radius. Within the NGC 7714 disk, clumpy H I gas is observed associated with star formation regions. Redshifted H I absorption is detected toward the strong starburst nucleus. We compare the observed morphology and gas kinematics with gas dynamical models in which a low-mass companion has an off-center prograde collision with the outer disk of a larger galaxy. These simulations suggest that the bridge in NGC 7714/7715 is a hybrid between the tidal bridges seen in systems like M51 and the purely gaseous "splash" bridges found in ring galaxies like the Cartwheel. The offset between the stars and gas in the bridge may be due to dissipative cloud-cloud collisions occurring during the impact of the two gaseous disks.
A New Search for Carbon Monoxide Absorption in the Transmission Spectrum of the Extrasolar Planet HD 209458b

We have revisited the search for carbon monoxide absorption features in transmission during the transit of the extrasolar planet HD 209458b. In 2002 August-September we acquired a total of 1077 high-resolution spectra (λ/δλ ~ 25,000) in the K-band (2 μm) wavelength region using NIRSPEC on the Keck II telescope during three transits. These data are more numerous and of better quality than the data analyzed in an initial search by Brown et al. Our analysis achieves a sensitivity sufficient to test the degree of CO absorption in the first-overtone bands during transit on the basis of plausible models of the planetary atmosphere. We analyze our observations by comparison with theoretical tangent geometry absorption spectra, computed by adding height-invariant ad hoc temperature perturbations to the model atmosphere of Sudarsky et al. and by treating cloud height as an adjustable parameter. We do not detect CO absorption. The strong 2-0 R-branch lines between 4320 and 4330 cm-1 have depths during transit less than 1.6 parts in 104 in units of the stellar continuum (3 σ limit) at a spectral resolving power of 25,000. Our analysis indicates a weakening similar to that found in the case of sodium, suggesting that a general masking mechanism is at work in the planetary atmosphere. Under the interpretation that this masking is provided by high clouds, our analysis defines the maximum cloud-top pressure (i.e., minimum height) as a function of the model atmospheric temperature. For the relatively hot model used by Charbonneau et al. to interpret their sodium detection, our CO limit requires cloud tops at or above 3.3 mbar, and these clouds must be opaque at a wavelength of 2 μm. High clouds comprised of submicron-sized particles are already present in some models but may not provide sufficient opacity to account for our CO result. Cooler model atmospheres, having smaller atmospheric scale heights and lower CO mixing ratios, may alleviate this problem to some extent. However, even models 500 K cooler than the Sudarsky et al. model require clouds above the 100 mbar level to be consistent with our observations. Our null result therefore requires clouds to exist at an observable level in the atmosphere of HD 209458b, unless this planet is dramatically colder than current belief.
Seeking gauge bileptons in linear colliders

Abstract A promising direction to find physics beyond the standard model is to look for violation of L e , μ , τ conservation. In particular the process e − e − → μ − μ − with the exchange of a gauge bilepton has a striking signal without background and is predicted in the most economical model to have a cross-section an order of magnitude higher than previous estimates.
The Spatial Distribution and Kinematics of Stellar Populations in E+A Galaxies

We use long-slit spectroscopic observations of the sample of E+A galaxies described by Zabludoff et al. to constrain the nature of the progenitors and remnants of the E+A phase of galaxy evolution. We measure spatially resolved kinematic properties of the young (1 Gyr) and old (few Gyr) stellar populations. The young stellar populations are more centrally concentrated than the older populations, but they are not confined to the galaxy core (radius 1 kpc). The kinematics of the old stellar population place 16 of 20 of our E+As on a trend parallel to the Faber-Jackson relation that is offset by ~0.6 mag in R. Eighteen of 20 E+As have v/σ < 1. As the young stars in these systems evolve, the luminosity offset will disappear, and the remnants will be pressure-supported systems that lie on the Faber-Jackson relation. Although Zabludoff et al. spectroscopically selected the most extreme E+A galaxies in the local volume, the sample is kinematically diverse: velocity dispersions range from 30 km s-1 to ~200 km s-1 over a luminosity range of MR = -19 to -22 + 5 log h. Combining these results with an estimate of the number of galaxies that experience an E+A phase, we conclude that the E+A phase of galaxy evolution is important in the development of a large fraction of spheroid-dominated galaxies over a wide range of luminosities and masses. Our kinematic observations, together with evidence that E+As have recently evolved from a vigorous star-forming phase to a quiescent phase (e.g., Couch & Sharples; Caldwell et al.) and that many have tidal features consistent with disklike progenitors (Zabludoff et al.), indicate that these galaxies are undergoing a transformation from gas-rich, star-forming, rotationally supported, disk-dominated galaxies into gas-poor, quiescent, pressure-supported, spheroid-dominated galaxies.