cssi/SciSciGPT-SciSciNet huggingface dataset:
A Precise distance indicator: Type Ia supernova multicolor light curve shapes

We present an empirical method that uses multicolor light-curve shapes (MLCSs) to estimate the luminosity, distance, and total line-of-sight extinction of Type Ia supernovae (SNe Ia). The empirical correlation between the MLCSs and the luminosity is derived from a " training set" of nine SN Ia light curves with independent distance and reddening estimates. We find that intrinsically dim SN Ia's are redder and have faster light curves than the bright ones, which are slow and blue. By 35 days after maximum, the intrinsic color variations become negligible. A formal treatment of extinction employing Bayes's theorem is used to estimate the best value and its uncertainty. Applying the MLCS method to both light curves and to color curves provides enough information to determine which supernovae are dim because they are distant, which are intrinsically dim, and which are dim because of extinction by dust. The precision of the MLCS distances is examined by constructing a Hubble diagram with an independent set of 20 SN Ia's. The dispersion of 0.12 mag indicates a typical distance accuracy of 5% for a single object, and the intercept yields a Hubble constant on the Sandage et al. Cepheid distance scale of H0 = 64 ± 3 (statistical) km s–1 Mpc–1 (±6 total error). The slope of 0.2010 ± 0.0035 mag over the distance interval 32.2 < μ < 38.3 yields the most precise confirmation of the linearity of the Hubble law.
Ensembles of plasmonic nanospheres at optical frequencies and a problem of negative index behavior

Arrays of metallic nanoparticles support individual and collective plasmonic excitations that contribute to unusual phenomena like surface-enhanced Raman scattering, anomalous transparency, negative index, and subwavelength resolution in various metamaterials. We examined the electromagnetic response of dual Kron’s lattice and films containing up to three monolayers of metallic nanospheres. It appears that open cubic Kron’s lattice exhibits ‘soft’ electromagnetic response but no negative index behavior. The close-packed arrays behave similarly: there are plasmon resonances and very high transmission at certain wavelengths that are much larger than the separation between the particles, and a ‘soft’ magnetic response, with small but positive effective index of refraction. It would be interesting to check these predictions experimentally.
Mixing of Clumpy Supernova Ejecta into Molecular Clouds

Several lines of evidence, from isotopic analyses of meteorites to studies of the Sun's elemental and isotopic composition, indicate that the solar system was contaminated early in its evolution by ejecta from a nearby supernova. Previous models have invoked supernova material being injected into an extant protoplanetary disk, or isotropically expanding ejecta sweeping over a distant (>10 pc) cloud core, simultaneously enriching it and triggering its collapse. Here, we consider a new astrophysical setting: the injection of clumpy supernova ejecta, as observed in the Cassiopeia A supernova remnant, into the molecular gas at the periphery of an H II region created by the supernova's progenitor star. To track these interactions, we have conducted a suite of high-resolution (15003 effective) three-dimensional numerical hydrodynamic simulations that follow the evolution of individual clumps as they move into molecular gas. Even at these high resolutions, our simulations do not quite achieve numerical convergence, due to the challenge of properly resolving the small-scale mixing of ejecta and molecular gas, although they do allow some robust conclusions to be drawn. Isotropically exploding ejecta do not penetrate into the molecular cloud or mix with it, but, if cooling is properly accounted for, clumpy ejecta penetrate to distances ~1018 cm and mix effectively with large regions of star-forming molecular gas. In fact, the ~2 M ☉ of high-metallicity ejecta from a single core-collapse supernova is likely to mix with ~2 × 104 M ☉ of molecular gas material as it is collapsing. Thus, all stars forming late (5 Myr) in the evolution of an H II region may be contaminated by supernova ejecta at the level ~10–4. This level of contamination is consistent with the abundances of short-lived radionuclides and possibly some stable isotopic shifts in the early solar system and is potentially consistent with the observed variability in stellar elemental abundances. Supernova contamination of forming planetary systems may be a common, universal process.
Physics studies with ICARUS and a hybrid ionization and scintillation fiber detector

Abstract We discuss the physics possibilities for the ICARUS detector currently being tested at CERN. The physics potential goes from a massive proton decay detector to the study of solar neutrinos. In addition, the detection of ν μ → ν τ andν c → ν τ will be possible with such a detector. One major topic involves the possibility of a complete determination of the MSW solar neutrino parameters with the ICARUS. The possibility of detecting WIMPS with a scintillating fiber liquid argon (Ar) detector or fiber xenon (Xe) detector doped with Ar is also described. Some comments on the measurement of the 42 Ar level from an experiment at the Gran Sasso Laboratory will be made.
Logconcavity versus Logconvexity: A Complete Characterization☆☆☆

Abstract This paper provides a complete characterization of logconcavity, an increasingly popular concept in the economics of uncertainty and information. New and known results are proven without assuming that density functions are differentiable. A systematic comparison between logconcavity and logconvexity is made and the source of the asymmetries between the two is investigated. The key difference is that logconcavity is preserved under one-sided integrations regardless of the types of distribution supports. This property, however, does not hold for logconvexity. Logconcavity for multivariate distributions is also discussed.Journal of Economic LiteratureClassification Number: D80.
Public Opinion and Foreign Aid: A Review Essay

The study of public opinion and foreign policy has a long history (Almond 1950; Converse 1964; Lippmann 1955). This history includes a long-standing debate over the utility of studying public opini...
Synthesis of Quinazolin-4(3H)-ones via Amidine N-Arylation

Pyrido[4,3-d]pyrimidin-4(3H)-one (1) was prepared by reacting 2-trifluoromethyl-4-iodo-nicotinic acid (2) with amidine 9a catalyzed by Pd2(dba)3 and Xantphos, followed by cyclization effected with HBTU and subsequent demethylation using PhBCl2. The amidine arylation method was found applicable for the syntheses of quinazolin-4(3H)-ones. Thus, reaction of 2-bromo or 2-iodo benzoate esters with amdidines afforded substituted quinazolin-4(3H)-ones in 44–89% yields.
RECOGNIZING DIFFERENT TYPES OF STOCHASTIC PROCESSES

We propose a new cross-correlation method that can recognize independent realizations of the same type of stochastic processes and can be used as a new kind of pattern recognition tool in biometrics, sensing, forensic, security and image processing applications. The method, which we call bispectrum correlation coefficient method, makes use of the cross-correlation of the bispectra. Three kinds of cross-correlation coefficients are introduced. To demonstrate the new method, six different random telegraph signals are tested, where four of them have the same power density spectrum. It is shown that the three coefficients can map the different stochastic processes to specific sub-volumes in a cube.
Transplantation of vascularized allogeneic skeletal muscle for scalp reconstruction in a renal transplant patient.

Background. We report the case of a vascularized allogeneic skeletal muscle transplant (VASM) and autologous skin grafting as rescue therapy for refractory squamous cell carcinoma of the scalp. Methods. A renal transplant recipient with recurrent squamous carcinoma of the scalp underwent an excision that resulted in a 11x14 cm 2 scalp defect with exposed cranium. At the time of multiorgan procurement, a section of rectus abdominis and external oblique muscle and fascia with its independent vascular bundle was isolated and stored in cold University of Wisconsin solution. The patient received methyl-prednisolone and rabbit antithymocyte globulin intravenously during scalp preparation, before single-vessel anastomosis of the deep inferior epigastric vascular bundle from the donor muscle to the recipient neck vessels. An autologous split-thickness skin graft was secured to the surface of the allogeneic muscle. Results. Immunosuppression was maintained with prednisone and cyclosporine. Serial VASM biopsies were used to evaluate acute rejection. Perivascular lymphocytic infiltrates and rare focal myonecrosis were evident on biopsy at 2 weeks postoperatively, and mycophenolate mofetil was added. Subsequent VASM biopsies showed predominately interstitial and perivascular T-cell lymphocytic infiltrates interpreted as consistent with mild rejection, but the allograft appeared intact without clinical evidence of rejection. On postoperative week 18, the mycophenolate mofetil was discontinued. There has been no evidence of recurrence or metastasis. The patient remains ambulatory with a healed scalp 12 months after the VASM. Conclusion. The success of this first allogeneic skeletal muscle transplant is encouraging and provides another reconstruction option for wounds in transplant patients on chronic immunosuppression.
On the Two-User Interference Channel With Lack of Knowledge of the Interference Codebook at One Receiver

In multiuser information theory, it is often assumed that every node in the network possesses all codebooks used in the network. This assumption may be impractical in distributed ad hoc, cognitive, or heterogeneous networks. This paper considers the two-user interference channel with one oblivious receiver (IC-OR), i.e., one receiver lacks knowledge of the interfering cookbook, whereas the other receiver knows both codebooks. This paper asks whether, and if so how much, the channel capacity of the IC-OR is reduced compared with that of the classical IC where both receivers know all codebooks. A novel outer bound is derived and shown to be achievable to within a gap for the class of injective semideterministic IC-ORs; the gap is shown to be zero for injective fully deterministic IC-ORs. An exact capacity result is shown for the general memoryless IC-OR when the nonoblivious receiver experiences very strong interference. For the linear deterministic IC-OR that models the Gaussian noise channel at high SNR, nonindependent identically distributed. Bernoulli(1/2) input bits are shown to achieve points not achievable by i.i.d. Bernoulli(1/2) input bits used in the same achievability scheme. For the real-valued Gaussian IC-OR, the gap is shown to be at most 1/2 bit per channel use, even though the set of optimal input distributions for the derived outer bound could not be determined. Toward understanding the Gaussian IC-OR, an achievability strategy is evaluated in which the input alphabets at the nonoblivious transmitter are a mixture of discrete and Gaussian random variables, where the cardinality of the discrete part is appropriately chosen as a function of the channel parameters. Surprisingly, as the oblivious receiver intuitively should not be able to jointly decode the intended and interfering messages (whose codebook is unavailable), it is shown that with this choice of input, the capacity region of the symmetric Gaussian IC-OR is to within 1/2 log (12πe)≈ 3.34 bits (per channel use per user) of an outer bound for the classical Gaussian IC with full codebook knowledge at both receivers.
The synthesis of Chebyshev broad-band impedance-matching ladder networks

Abstract It is shown that, in most cases, the most practical RLC load can be optimally matched to a resistive generator over a finite frequency band by a Chebyshev ladder equalizer. The results are surprisingly simple. We only need to solve a cubic equation. The significance of these results is that we avoid the use of the Darlington type-C section for the lowpass equalizer and the Darlington type-E section for the bandpass equalizer and circumvent the need for solving the nonlinear equations or using the design curves, thereby reducing the design to a simple arithmetic.
Probing galaxy formation with He II cooling lines

Using high-resolution cosmological simulations, we study hydrogen and helium gravitational cooling radiation from gas accretion by young galaxies. We focus on the He II cooling lines, which arise from gas with a different temperature history (Tmax ~ 105 K) than H I line-emitting gas. We examine whether three major atomic cooling lines, H I λ1216, He II λ1640, and He II λ304, are observable, finding that Lyα and He II λ1640 cooling emission at z = 2-3 are potentially detectable with deep narrowband (R > 100) imaging and/or spectroscopy from the ground. While the expected strength of H I λ1216 cooling emission depends strongly on the treatment of the self-shielded phase of the IGM in the simulations, our predictions for the He II λ1640 line are more robust, because the He II emissivity is negligible below T ~ 104.5 K and less sensitive to the UV background. Although He II λ1640 cooling emission is fainter than Lyα by at least a factor of 10 and, unlike Lyα, might not be resolved spatially with current observational facilities, it is more suitable to study gas accretion in the galaxy formation process because it is optically thin and less contaminated by the recombination lines from star-forming galaxies. The He II λ1640 line can be used to distinguish among mechanisms for powering the so-called Lyα blobs—including gravitational cooling radiation, photoionization by stellar populations, and starburst-driven superwinds—because (1) He II λ1640 emission is limited to very low metallicity [log(Z/Z☉) -5.3] and Population III stars and (2) the blob's kinematics are probed unambiguously through the He II line width, which for cooling radiation is narrower (σ < 400 km s-1) than typical wind speeds.
The history of the ITU, with particular attention to the CCITT and the CCIR, and the latter's relations with URSI

This paper is designed to provide members of URSI with background information about the International Telecommunication Union and its two international consultative committees (CCIs): the International Radio Consultative Committee (CCIR) and the International Telephone and Telegraph Consultative Committee (CCITT). Toward this end the history of the present ITU and its predecessor organizations, the International Telegraph Union and the Radio Telegraph Union, is reviewed. The history, structure, and schedule of the CCIs are then treated. Finally, it is suggested that, in the future, contacts between URSI and the CCIR will be both richer and of increasing importance.
Distributional and Classical Solutions to the Cauchy Boltzmann Problem for Soft Potentials with Integrable Angular Cross Section

This paper focuses on the study of existence and uniqueness of distributional and classical solutions to the Cauchy Boltzmann problem for the soft potential case assuming S n−1 integrability of the angular part of the collision kernel (Grad cut-off assumption). For this purpose we revisit the Kaniel–Shinbrot iteration technique to present an elementary proof of existence and uniqueness results that includes the large data near local Maxwellian regime with possibly infinite initial mass. We study the propagation of regularity using a recent estimate for the positive collision operator given in (Alonso et al. in Convolution inequalities for the Boltzmann collision operator. arXiv:0902.0507 [math.AP]) , by E. Carneiro and the authors, that allows us to show such propagation without additional conditions on the collision kernel. Finally, an L p -stability result (with 1≤p≤∞) is presented assuming the aforementioned condition.
Weak lensing, dark matter and dark energy

Weak gravitational lensing is rapidly becoming one of the principal probes of dark matter and dark energy in the universe. In this brief review we outline how weak lensing helps determine the structure of dark matter halos, measure the expansion rate of the universe, and distinguish between modified gravity and dark energy explanations for the acceleration of the universe. We also discuss requirements on the control of systematic errors so that the systematics do not appreciably degrade the power of weak lensing as a cosmological probe.
Stored mafic/ultramafic crust and early Archean mantle depletion

The global Nd isotopic evidence for early mantle depletion, which shows that some enriched reservoir must have persisted for at least 300 Ma in the early Archean, is discussed. Numerical models of the isotopic effects of melt extraction from the mantle are used to show that early oceanic crust is a more likely candidate for the enriched reservoir than early continental crust. It is suggested that subduction of an early mafic/ultramafic crust and temporary storage may be responsible for the depletion and high epsilon(Nd) values of the Archean upper mantle.
Invariants of legendrian knots in circle bundles

Let M be a circle bundle over a Riemann surface that supports a contact structure transverse to the fibers. This paper presents a combinatorial definition of a differential graded algebra (DGA) that is an invariant of Legendrian knots in M. The invariant generalizes Chekanov's combinatorial DGA invariant of Legendrian knots in the standard contact 3-space using ideas from Eliashberg, Givental, and Hofer's contact homology. The main difficulty lies in dealing with what are ostensibly 1-parameter families of generators for the DGA; these are solved using "Morse–Bott" techniques. As an application, the invariant is used to distinguish two Legendrian knots that are smoothly isotopic, realize a nontrivial homology class, but are not Legendrian isotopic.
Hadronic Monte Carlo Transport: A Very Personal View

Much to the disappointment of many, our distinguished speaker for the initial plenary session has been unable to attend our conference. I was prevailed upon by the conference organization to present a talk which, as prescribed, will be of a historical nature, but as the title describes, will also be a very personal view. Perhaps the opinions expressed will find sympathy with my associates around the world who have devoted their efforts to and found some satisfaction with providing the code tools for radiation transport to a large, and occasional anxious, community of users.
POLLUTION OF SINGLE WHITE DWARFS BY ACCRETION OF MANY SMALL ASTEROIDS

Extrapolating from the solar system's asteroid belt, we propose that externally contaminated white dwarfs without an infrared excess may be experiencing continuous accretion of gas-phase material that is ultimately derived from the tidal destruction of multiple small asteroids. If this scenario is correct, then observations of metal-polluted white dwarfs may lead to determination of the bulk elemental compositions of ensembles of extrasolar minor planets.
Moderate Reynolds number flows through periodic and random arrays of aligned cylinders

The effects of fluid inertia on the pressure drop required to drive fluid flow through periodic and random arrays of aligned cylinders is investigated. Numerical simulations using a lattice-Boltzmann formulation are performed for Reynolds numbers up to about 180.The magnitude of the drag per unit length on cylinders in a square array at moderate Reynolds number is strongly dependent on the orientation of the drag (or pressure gradient) with respect to the axes of the array; this contrasts with Stokes flow through a square array, which is characterized by an isotropic permeability. Transitions to time-oscillatory and chaotically varying flows are observed at critical Reynolds numbers that depend on the orientation of the pressure gradient and the volume fraction.In the limit Re[Lt ]1, the mean drag per unit length, F, in both periodic and random arrays, is given by F/(μU) =k1+k2Re2, where μ is the fluid viscosity, U is the mean velocity in the bed, and k1 and k2 are functions of the solid volume fraction ϕ. Theoretical analyses based on point-particle and lubrication approximations are used to determine these coefficients in the limits of small and large concentration, respectively.In random arrays, the drag makes a transition from a quadratic to a linear Re-dependence at Reynolds numbers of between 2 and 5. Thus, the empirical Ergun formula, F/(μU) =c1+c2Re, is applicable for Re>5. We determine the constants c1 and c2 over a wide range of ϕ. The relative importance of inertia becomes smaller as the volume fraction approaches close packing, because the largest contribution to the dissipation in this limit comes from the viscous lubrication flow in the small gaps between the cylinders.
Transcendence measures and algebraic growth of entire functions

In this paper we obtain estimates for certain transcendence measures of an entire function f. Using these estimates, we prove Bernstein, doubling and Markov inequalities for a polynomial P(z,w) in ℂ2 along the graph of f. These inequalities provide, in turn, estimates for the number of zeros of the function P(z,f(z)) in the disk of radius r, in terms of the degree of P and of r. Our estimates hold for arbitrary entire functions f of finite order, and for a subsequence {n j } of degrees of polynomials. But for special classes of functions, including the Riemann ζ-function, they hold for all degrees and are asymptotically best possible. From this theory we derive lower estimates for a certain algebraic measure of a set of values f(E), in terms of the size of the set E.
Integral constraints and performance limits on complementary sensitivity: Discrete-time systems

Abstract We study performance limitation issues for multivariable discrete-time feedback systems. The complementary sensitivity function is employed as a performance measure, and Bode and Poisson-type integral inequalities and H ∞ -type performance limits are derived. The results exhibit frequency-dependent constraints as well as best achievable limits on the complementary sensitivity function, which are shown to be determined by nonminimum phase zeros, unstable poles, and time delays. In particular, the directions of such zeros and poles are seen to play a central role to this effect.
Some modifications to, and operational experiences with, the two-dimensional, finite-difference, boundary-layer code, STAN5

The two-dimensional, finite-difference boundary-layer code, STAN5, is the primary tool used at the NASA-Lewis Research Center for predicting turbine blade gas-side heat-transfer coefficients. A number of modifications have been made to the program to enhance its usefulness for these calculations. Experience in using STAN5 has identified some problems in the program that can be treated through program input, without modifying the program. These include the presence of a small separation bubble near the leading edge, and the effect of full-coverage film cooling on transition to turbulence. Some of the techniques used to treat these problems are described.
A review of rotating blade noise technology

Abstract Rotating blade noise is a topic of wide concern because it is the source of a variety of noise problems. These concerns range from safety, on the one hand, to community acceptability on the other. The purpose of this paper is to provide a general technical background for the problems of noise due to rotating blades. The topics to be covered are the following: the vehicles and components for which these problems are pertinent, the nature of the noise produced, the sources of the noise, concepts of noise generation, identification of the significant parameters in noise generation and reduction, and the methods of noise prediction. Both free rotors and ducted rotors are considered. In addition to the references cited in the text, this paper presents a bibliography of some of the more recent work (since 1968) in the areas of rotor and propeller noise, compressor and fan noise, and duct acoustics.
An Energy Bound Deduced from the Vanishing of the Radiation Reaction Force during Uniform Acceleration

We deduce from energy conservation a lower bound on the mass of any system capable of imparting a constant acceleration to a charged body. We also point out a connection between this bound and the so-called dominant energy condition of general relativity.
Uses of polynuclear metal complexes to develop designed dispersions of supported metal oxides

Abstract The new generation of catalysts will be designed according to the traditional methods of scientific pursuit using the relationships of catalytic properties to surface structure. However, new methods of catalyst synthesis are necessary to usher in this new generation of catalysts. We believe that one possible route to this catalyst synthesis will begin by fabricating the catalytic ensemble as a discrete metal complex in a single crystal which will allow for its structure to be known by diffraction methods. This crystal will be solvated into discrete metal complexes which are attached to the appropriate ceramic support as a single layer of such replicates. In the ideal synthesis, the catalytic ensemble will require no further treatment to render it active and the structure of the ensemble on the ceramic is the same as its structure in the single crystal. For these materials, the relationships between structure and properties are unambiguous and the dream of creating heterogeneous catalysts with homogeneous properties becomes a reality. Unfortunately, the synthesis of active metal complexes may be limited to very small number. In these cases when no active metal complex may be synthesized, alternative preparations may require further treatment to render active the metal complexes. Such active catalysts may be developed after thermolysis of the supported metal complexes to form a “designed dispersion” of the metal oxides.
An Overview of CCD Development at Lawrence Berkeley National Laboratory

Fully depleted, back-illuminated charge-coupled devices fabricated at Lawrence Berkeley National Laboratory on high-resistivity silicon are described. Device operation and technology are discussed, as well as the results on telescopes and future plans.
Chiral tropocoronands: Synthesis and metal complex formation

Abstract The synthesis of several chiral tropocoronands based on 1,2-cyclohexanediamine ( 7 ) and 1,2-diphenylethylenediamine ( 8 ) has been accomplished. X-ray crystallography has confirmed the structure of two metallated derivatives, Cu(II)(TC-4,cyhex) ( 9 ) and Ni(II)(TC-4,cyhex) ( 10 ), that are indicative of the types of chiral complexes that can be formed from these systems.
Extinction and cellular instability of premixed tubular flames

Extinction and cellular instabilities are investigated in premixed tubular flames. A tubular burner has recently been designed and constructed to be capable of operating under a wide range of conditions that allow more accurate and detailed study of tubular premixed and non-premixed flames. Extinction measurements of tubular flames can be carried out through the entire equivalence ratio spectrum for various types of fuels without introducing serious turbulent effects. In this study, the extinction conditions of premixed tubular flames generated by H2/O2 or CH4/O2 mixed with various inert diluents (Ar, CO2, N2) and enriched oxygen are measured. In addition, the onset conditions for flame instability at different cell numbers are reported. Petal shaped cellular flames with symmetric regions of local extinction are observed for lean H2 tubular flames with low Lewis numbers. Wrinkled flames with no local extinction are observed for nearly equidiffusive lean CH4 tubular flames. The combined effects of curvature, diffusive-thermal instability and hydrodynamics are thought to be responsible for the cellular structure. The lack of extinction in the nearly equidiffusive lean CH4 tubular flames indicate that strong diffusive-thermal effects due to non-unity Lewis number are required to produce local extinction in the cellular structure of tubular flames.
Passive immunization with human neutralizing monoclonal antibodies: correlates of protective immunity against HIV

Passive immunization with synergistic combinations of human monoclonal antibodies (mAbs) directed against conserved epitopes of the human immunodeficiency virus (HIV) envelope completely protected 13 out of 16 rhesus monkeys challenged intravenously or orally with chimeric simian-human immunodeficiency virus (SHIV) strains; partial protection was seen in another two. A high degree of protection was seen among orally challenged neonates. Thus, we propose that passive immunization with synergistic combinations of neutralizing human mAbs may be effective in preventing maternal HIV transmission when given as post-exposure prophylaxis at birth and as prophylaxis against milk-borne transmission. Because we only used mAbs with well-defined epitope specificities, our studies also yield key information for designing AIDS vaccines: the correlates of immune protection. Vaccine strategies that can evoke antibody responses to epitopes recognized by the mAbs used in our primate studies could be important components of successful AIDS vaccines.
Early and Rapid Merging as a Formation Mechanism of Massive Galaxies: Empirical Constraints

We present the results of a series of empirical computations regarding the role of major mergers in forming the stellar masses of modern galaxies based on measured galaxy merger and star formation histories from z ~ 0.5 to 3. We reconstruct the merger history of normal field galaxies from z ~ 3 to z ~ 0 as a function of initial mass using published pair fractions and merger fractions from structural analyses. We calibrate the observed merger timescale and mass ratios for galaxy mergers using self-consistent N-body models of mergers with mass ratios from 1?:?1 to 1?:?5 at various orbital properties and viewing angles. We use these simulations to determine the timescales and mass ratios that produce structures that would be identified as major mergers. Based on these calculations, we argue that a typical massive galaxy at z ~ 3 with M* > 1010 M? undergoes 4.4 major mergers at z > 1. We find that by z ~ 1.5 the stellar mass of an average massive galaxy is relatively established, a scenario qualitatively favored in a ?-dominated universe. We argue that the final masses of these systems increase by as much as a factor of 100, allowing Lyman break galaxies, which tend to have low stellar masses, to become the most massive galaxies in today's universe with M > M*. Induced star formation, however, only accounts for 10%-30% of the stellar mass formed in these galaxies at z < 3. A comparison to semianalytic models of galaxy formation shows that cold dark matter (CDM) models consistently underpredict the merger fraction, and rate of merging, of massive galaxies at high redshift. This suggests that massive galaxy formation occurs through more merging than predicted in CDM models, rather than a rapid early collapse.
Creating offshore-ready it professionals: A global perspective and strong collaborative skills are needed

Outsourcing of IT functions has become a widespread corporate practice, which has naturally led to concerns among IT works about how this affects their jobs. The issue is complex, and many companies are bringing their IT functions back inhouse. In light of this complexity, what skills do IT workers need to be com-petitive? We address this question first by reviewing the literature and then by examining two corporate case studies that have dealt with outsourcing issues. Based on this view of outsourcing, we discuss the skills that can provide a com-petitive advantage in the current environment.
Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems

Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3-D unsteady, full wheel CRP CFD computations and aero-acoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full wheel unsteady 3-D RANS simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method were extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in the literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was re-designed for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the re-designed CRP demonstrated an average reduction of 7.25 dB in mean SPL computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the re-designed CRP demonstrated a reduction of 9.2 EPNdB and 8.6 EPNdB at the FAR 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.Copyright © 2010 by ASME
Synthesis of novel C2-C3'N-linked macrocyclic taxoids by means of highly regioselective Heck macrocyclization.

Novel C2−C3‘N-linked macrocyclic taxoids are synthesized using intramolecular Heck reaction in the key step. Macrocyclization proceeds with high regioselectivity in good yield. Taxoids bearing an olefin moiety at C2 and an iodide at C3‘N give exo-products exclusively. However, the endo-products are formed with up to 100% regioselectivity just by switching the positions of the olefin and the iodide moieties. Some of these macrocyclic taxoids are significantly cytotoxic.
Optimal H ∞ Control for Linear Periodically Time-Varying Systems in Hard Disk Drives

Periodicity frequently occurs in hard disk drives (HDDs) whose servo systems with periodic phenomena can be usually modeled as linear periodically time-varying (LPTV) systems. This paper discusses optimal H∞ control synthesis for discrete-time LPTV systems via discrete Riccati equations. First, an explicit minimum entropy H∞ controller for general time-varying systems is obtained. Subsequently, the developed control synthesis algorithm is applied to LPTV systems and it is shown that the resulting controllers are periodic. The proposed control synthesis technique is evaluated through both single and multirate optimal H∞ track-following control designs. The single-rate servo design shows that our proposed control synthesis technique is more numerically robust in calculating optimal H∞ controllers for discrete-time linear time-invariant systems than the MATLAB function of “hinfsyn,” while the multirate servo design validates its ability of synthesizing multirate controllers to achieve the robust performance of a desired error-rejection function. Moreover, an experimental study-in which the developed control synthesis algorithm on a real HDD with missing position error signal sampling data is implemented-further demonstrates its effectiveness in handling LPTV systems with a large period and attaining desirable disturbance attenuation.
Testing the Space of the Virtual

Recently availed modes of mediated communication and perception, generally categorised as 'virtual experiences', have offered the designer of space a new array of spatial conditions to contend with...
Latest results from heavy quark simulations

I review the status of b b ¯ and c c ¯ calculations, numerical and analytic. I discuss the extraction of αs and quark masses from spectrum calculations. I compare the NRQCD and Improved Heavy Wilson formulations of heavy quarks, and discuss recent calculations using a Heavy Staggered formulation.
Active Vibration Damping of the Space Shuttle Remote Manipulator System

Controls-structures interaction is a technology currently under development for application to large flexible space vehicles. The goal of this technology is the improvement of spacecraft performance through active control of the structural dynamic response of the vehicle. This goal is particularly important for modern spacecraft designs where large size and reduced stiffness make structural response a significant contributor to vehicle dynamics. Analysis and design methods have been developed to analyze and predict flexible spacecraft performance, but the technology remains largely unvalidated by hardware experiments, demonstrations, or applications, particularly in-space flight applications. One potential application considered is to provide active damping augmentation of the Space Shuttle remote manipulator system. The objective of actively damping the manipulator is to demonstrate improved structural dynamic response following payload maneuvers and Shuttle reaction control system thruster firings. This paper describes an initial analysis effort to determine the feasibility of controlling the flexible dynamic response of the arm. The approach to the study is summarized and results from both linear and nonlinear performance analyses of candidate control laws are presented. Results indicate that significant improvement in dynamic response can be achieved through active control if measured arm tip acceleration was made available for feedback.
Spatially-Aware Temporal Anomaly Mapping of Gamma Spectra

For security, environmental, and regulatory purposes it is useful to continuously monitor wide areas for unexpected changes in radioactivity. We report on a temporal anomaly detection algorithm which uses mobile detectors to build a spatial map of background spectra, allowing sensitive detection of any anomalies through many days or months of monitoring. We adapt previously-developed anomaly detection methods, which compare spectral shape rather than count rate, to function with limited background data, allowing sensitive detection of small changes in spectral shape from day to day. To demonstrate this technique we collected daily observations over the period of six weeks on a 0.33 square mile research campus and performed source injection simulations.
Perturbations of the coupled Jeffery–Stokes equations

This paper seeks to provide clues as to why experimental evidence for the alignment of slender fibres in semi-dilute suspensions under shear flows does not match theoretical predictions. This paper posits that the hydrodynamic interactions between the different fibres that might be responsible for the deviation from theory, can at least partially be modelled by the coupling between Jeffery's equation and Stokes' equation. It is proposed that if the initial data are slightly non-uniform, in that the probability distribution of the orientation has small spatial variations, then there is feedback via Stokes' equation that causes these non-uniformities to grow significantly in short amounts of time, so that the standard uncoupled Jeffery's equation becomes a poor predictor when the volume ratio of fibres to fluid is not extremely low. This paper provides numerical evidence, involving spectral analysis of the linearization of the perturbation equation, to support this theory.
Physical and Chemical Properties of Calcium Phosphates for Solid State Pharmaceutical Formulations

The physical and chemical properties of pharmaceutical phosphates are reviewed, with particular emphasis on chemistry of syntehsis, nomenclature, physico-chemical properties and tableting character...
Critical analysis and remedy of switching failures in straintronic logic using Bennett clocking in the presence of thermal fluctuations

Straintronic logic is a promising platform for beyond Moore's law computing. Using Bennett clocking mechanism, information can propagate through an array of strain-mediated multiferroic nanomagnets, exploiting the dipolar coupling between the magnets without having to physically interconnect them. Here, we perform a critical analysis of switching failures, i.e., error in information propagation due to thermal fluctuations through a chain of such straintronic devices. We solved stochastic Landau-Lifshitz-Gilbert equation considering room-temperature thermal perturbations and show that magnetization switching may fail due to inherent magnetization dynamics accompanied by thermally broadened switching delay distribution. Avenues available to circumvent such issue are proposed.
Sensor data enhancement of ballistic missile warheads using an affine motion model

Neutralizing the threat of an incoming ballistic missile is a difficult task. Often the missile disintegrates, leaving the warhead surrounded by a number of ballistic fragments. Among these fragments only the warhead must be intercepted. Thus the challenge is for the interceptor to identify and track the warhead so that a successful strike can be achieved. This paper addresses the problem of using noisy image sequence data captured by on-board sensors in the nose cone of the interceptor to detect warheads among fragments. Detection and tracking necessitates the extraction of reliable motion estimates, which is often difficult when the data sequence is noisy. We propose a simple algorithm that exploits both spatial and temporal correlation to suppress noise in the observed image sequence. Our algorithm calculates reliable estimates of the global motion caused by camera movement and uses these motion estimates to reduce significantly the noise in the video sequence.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Asymmetric Diels-Alder reaction: Cis-1-arylsulfonamido-2-indanols as highly effective chiral auxiliaries

Lewis acid promoted Diels-Alder reaction of acrylate esters of cis-1-arylsulfonamido-2-indanols and cyclopentadiene provided exclusively endo-adducts with high endo-diastereoselectivities.
Chemical potential effects on neutrino diffusion in supernovae

The validity of imposing a zero chemical potential for neutrinos in hydrodynamic calculations of collapsing supernovae is investigated in the diffusion approximation of neutrino transport. A coupled system of equations is solved for neutrino and energy diffusion fluxes as well as lepton diffusion in a collapsing supernovae ambient medium, and the results indicate a substantial growth in the neutrino chemical potential for densities greater than 10 to the 12th power gm/cu cm. The rate of energy transport is shown to be significantly affected by increases in Fermi integrals and chemical-potential gradients accompanied by decreases in temperature, and the extent of neutrino particle/antiparticle reactions is found also to affect energy diffusion rates. It is concluded that the photon-like behavior usually assumed for neutrinos may be incorrect and that an extension of the Sn transport approximation to include lepton characteristics is necessary for a definitive answer to the question of neutrino transport in supernovae.
COBE observations of the cosmic infrared background

Abstract The diffuse infrared background experiment (DIRBE) on the COsmic Background Explorer (COBE) measured the total infrared signal seen from space at a distance of 1 AU from the Sun. Using time variations as the Earth went around the Sun, it is possible to remove most of the foreground signal produced by the interplanetary dust cloud [zodiacal light]. By correlating the DIRBE signal with the column density of atomic hydrogen measured using the 21 cm line, it is possible to remove most of the foreground signal produced by interstellar dust, although one must still be concerned by dust associated with H 2 (molecular gas) and H II (the warm ionized medium). DIRBE was not able to determine the cosmic infrared background (CIRB) in the 5–60 μm wavelength range, but does detect both a far infrared background and a near infrared background. The far infrared background has an integrated intensity of about 34 nW/m 2 /sr, while the near infrared and optical extragalactic background has about 59 nW/m 2 /sr. The far infrared absolute spectrophotometer (FIRAS) on COBE has been used to constrain the long wavelength tail of the far infrared background but a wide range of intensities at 850 μm are compatible with the FIRAS data. Thus the fraction of the CIRB produced by SCUBA sources has large uncertainties in both the numerator and the denominator.
Spatially Resolved Observations of the Galactic Center Source IRS 21

We present diffraction-limited 2-25 μm images obtained with the W. M. Keck 10 m telescopes that spatially resolve the cool source IRS 21, one of a small group of enigmatic objects in the central parsec of our Galaxy that have eluded classification. Modeled as a Gaussian, the azimuthally averaged intensity profile of IRS 21 has a half-width at half-maximum (HWHM) size of 650 ± 80 AU at 2.2 μm and an average HWHM size of 1600 ± 200 AU at mid-infrared wavelengths. These large apparent sizes imply an extended distribution of dust. The mid-infrared color map indicates that IRS 21 is a self-luminous source rather than an externally heated dust clump as originally suggested. The spectral energy distribution has distinct near- and mid-infrared components. A simple radiative transfer code, which simultaneously fits the near- and mid-infrared photometry and intensity profiles, supports a model in which the near-infrared radiation is scattered and extincted light from an embedded central source, while the mid-infrared emission is from thermally reradiating silicate dust. We argue that IRS 21 (and by analogy, the other luminous sources along the Northern Arm) is a massive star experiencing rapid mass loss and plowing through the Northern Arm, thereby generating a bow shock, which is spatially resolved in our observations.
Does m*g* Diverge at a Finite Electron Density in Silicon Inversion Layers?

For the two-dimensional electron system in silicon MOSFET's, the scaled magnetoconductivity has been shown to exhibit critical behavior at finite density n 0 . Analysis of these magnetotransport experiments yields a product g * m * that diverges at this density (here g * is the interaction-enhanced Lande g -factor and m * is the effective mass). This claim has been disputed based on direct determinations of the g * m * obtained from Shubnikov–de Haas measurements. We briefly review these experiments, and possible sources of the discrepancies.
Acidity constants of benzimidazolium ketone and pyridinium aldehyde hydrates

Acidity constants (pKa) of the hydroxyl groups of the quaternary heterocyclonium carbinols 2-hydroxymethyl-1-methylpyridinium and 2-(1-hydroxyethyl)-1,3-dimethylbenzimidazolium ions are 11.5 ± 0.5. Acidity constants of the corresponding gem diols, the hydrates of 2-formyl-1-methyl-pyridinium and 2-acetyl-1,3-dimethylbenzimidazolium ions hence are estimated to be 9.0 ± 0.5. Accordingly, acidity constants of the hydroxyl groups of pyridine aldehyde salt hydrates are 12-13, not 4-5 as previously reported; and conversely, acidity constants of the pyridinium groups are 4-5, not 12-13.