cssi/SciSciGPT-SciSciNet huggingface dataset:
Equipartition and retrieval of Green’s function.

Research on retrieval of Green’s function by correlation of ambient noise has seen enormous growth in recent years, in particular in seismology, exploration geophysics, and ocean acoustics, and in general whenever receivers are convenient while active sources are not. As such it resembles various other methodologies such as daylight imaging, sound shadows, and correlations with noisy sources which are, in fact, different in principle. Retrieval has its theoretical origin in the concept of wave equipartition and the fluctuation dissipation theorem of statistical thermal mechanics. Proof that the Greens function is retrieved from the correlations of noise is the simplest and most elegant in the thermal case, but acoustic noise is rarely thermal and those proofs do not always apply. Nevertheless, diffuse acoustic wave fields will sometimes approximate equipartition (it is routinely assumed in room acoustics and statistical energy analysis), and retrieval is often strikingly feasible even where that approxima...
LIMITING VALUE OF HIGHER MAHLER MEASURE

Abstract We consider the k -higher Mahler measure m k ( P ) of a Laurent polynomial P as the integral of log k | P | over the complex unit circle. In this paper we derive an explicit formula for the value of | m k ( P ) | / k ! as k → ∞ .
The charmonium spectrum on the lattice: A status report

Abstract We present our most recent results on the charmonium spectrum using relativistic Wilson fermions. We study the dependence of the spectrum on the charm quark mass and the Wohlert-Sheikholeslami improvement term.
Graphs with equal chromatic symmetric functions

In 1995 Stanley introduced the chromatic symmetric function X"G associated to a simple graph G as a generalization of the chromatic polynomial of G. In this paper we present a novel technique to write X"G as a linear combination of chromatic symmetric functions of smaller graphs. We use this technique to give a sufficient condition for two graphs to have the same chromatic symmetric function. We then construct an infinite family of pairs of unicyclic graphs with the same chromatic symmetric function, answering the question posed by Martin, Morin, and Wagner of whether such a pair exists. Finally, we approach the problem of whether it is possible to determine a tree from its chromatic symmetric function. Working towards an answer to this question, we give a classification theorem for single-centroid trees in terms of data closely related to its chromatic symmetric function.
Synthesis and characterization of partially fluorinated hydrophobic–hydrophilic multiblock copolymers containing sulfonate groups for proton exchange membrane

Abstract A new hydrophobic–hydrophilic multiblock copolymer has been successfully synthesized based on the careful coupling of a fluorine terminated poly(arylene ether ketone) (6FK) hydrophobic oligomer and a phenoxide terminated disulfonated poly(arylene ether sulfone) (BPSH) hydrophilic oligomer. 19 F and 1 H NMR spectra were used to characterize the oligomers’ molecular weights and multiblock copolymer's structure. The comparison of the multiblock copolymer 13 C NMR spectrum with that of the random copolymer showed that the transetherification side reaction was minimized in this synthesis. The morphologies of membranes were investigated by tapping mode atomic force microscopy (AFM), which showed that the multiblock membrane acidified by the high temperature method has sharp phase separation. Membrane properties like protonic conductivity, water uptake, and self-diffusion coefficient of water as a function of temperature and relative humidity (RH) were characterized for the multiblock copolymer and compared with ketone type random copolymers at similar ion exchange capacity value and Nafion ® controls. The multiblock copolymers are promising candidates for proton exchange membranes especially for applications at high temperatures and low relative humidity.
The Steinberg symbol and special values of L-functions

The main results of this article concern the definition of a compactly supported cohomology class for the congruence group Γ 0 (p n ) with values in the second Milnor K-group (modulo 2-torsion) of the ring of p-integers of the cyclotomic extension Q(μ p n). We endow this cohomology group with a natural action of the standard Hecke operators and discuss the existence of special Hecke eigenclasses in its parabolic cohomology. Moreover, for n = 1, assuming the non-degeneracy of a certain pairing on p-units induced by the Steinberg symbol when (p, k) is an irregular pair, i.e. p| B k /k, we show that the values of the above pairing are congruent mod p to the L-values of a weight k, level 1 cusp form which satisfies Eisenstein-type congruences mod p, a result that was predicted by a conjecture of R. Sharifi.
VLF wave-injection experiments from Siple Station, Antarctica

Abstract The background of VLF wave-particle experiments from Siple Station, Antarctica, is briefly reviewed. Most of these results are interpreted in terms of Doppler shifted cyclotron interaction between energetic electrons and the VLF waves near the equatorial plane. Single frequency ducted signals that exceed a certain ‘threshold’ intensity are observed at the conjugate point (Roberval, or Lake Mistissini, Quebec) to be amplified 30–50 dB, with temporal growth rates of 30–200 dB/s. Following saturation, variable frequency emissions are triggered. With the addition of a second signal, separated in frequency from the first by Δƒ Hz, signal growth at both frequencies is reduced and sidebands are generated at frequencies separated from the carriers by integer multiples (up to seven) of Δƒ. The sidebands are attributed to short emissions triggered by the beats between the two input carriers. Midlatitude magnetospheric hiss is crudely simulated by a sequence of 10 ms pulses whose frequencies are chosen randomly within a 400 Hz band. Results show that certain combinations of 10 ms pulses link together to form chorus-like elements, suggesting a common origin for hiss and chorus. In contrast to the equatorial region phenomena are low altitude (1000–8000 km) satellite observations of narrowband Siple pulses showing increases in bandwidth of up to 1000 Hz with impulsive triggered emissions of similar bandwidth; these phenomena are interpreted in terms of a new type of quasi-electrostatic plasma instability in the subauroral region of the magnetosphere, involving 200 m wide field aligned irregularities and occurring at frequencies near the lower hybrid resonance frequency. A new crossed dipole antenna at Siple Station that generates left-hand, right-hand, or linear polarization is used to increase the effective radiated power and to perform polarization experiments.
Energy gap of Kronig-Penney-type hydrogenated graphene superlattices

The electronic structure of graphene-graphane superlattices with armchair interfaces is investigated with first-principles density-functional theory. By separately varying the widths, we find that the energy gap ${E}_{g}$ is inversely proportional to the width of the graphene strip and that the gap increases as the hydrogenated strip becomes wider due to the enhanced confinement effect. It is further demonstrated that, unlike other graphene nanostructures, the superlattices exhibit both direct and indirect band gaps without external perturbations. This peculiarity in the nature of ${E}_{g}$ originates from the different connection structures of the symmetrized wave function at the boundary between adjacent unit cells due to the reflection symmetry of the superlattices. These findings suggest that the optical as well as electronic properties of graphene superlattices can be controlled through selective chemical functionalization.
Optical Neural Networks

The trade-off between the number of neurons that can be implemented with a single correlator and the shift invariance that each neuron has is investigated. A new type of correlator implemented with a planar hologram is described whose shift invariance can be controlled by setting the position of the hologram properly. The shift invariance and the capacity of correlators implemented with volume holograms is also investigated.
Constructing alternatives to structural adjustment in Africa

Structural adjustment in Africa is based on neo‐classical economic principles derived from the experience of industrialisation in Britain and the United States. Neo‐classical economics claims that unregulated markets maximise output across contexts. However, this naturalisation of markets neglects that they are actively constituted by actors with different capabilities and levels of power. Structural adjustment has failed because comprehensive liberalisation has led to the autonomous development of the trade and financial sectors, to the detriment of production. Appropriate development strategies must recognise the necessity of regulating trade and finance in order to channel resources towards production, as in the developmental states of East Asia. However, in order to be successful, such strategies must be embedded in Africa's political economy. Development will require a remaking of both African states and the international financial institutions which dictate their economic policies.
Cryogenic and thermal design for the space infrared telescope facility (SIRTF)

The 1-meter class cryogenically cooled Space Infrared Telescope Facility (SIRTF) planned by NASA, is scheduled for a 1992 launch. SIRTF would be deployed from the Shuttle, and placed into a sun synchronous polar orbit of 700 km. The facility has been defined for a mission with a minimum initial lifetime of one year in orbit with mission extension that could be made possible through in-orbit servicing of the superfluid helium cryogenic system, and use of a thermal control system. The superfluid dewar would use an orbital disconnect system for the tank supports, and vapor cooling of the barrel baffle. The transient analysis of the design shows that the superfluid helium tank with no active feedback comes within temperature requirements for the nominal orbital aperture heat load, quiescent instrument, and chopper conditions.
Analog simulation of the re-entry of a ballistic missile warhead and multiple decoys

The basic problem considered here is the computation of the reentry trajectory of a single ballistic missile warhead as well as the trajectories of a number of decoys which originate from the warhead trajectory. Suitable three dimensional equations of motion are presented for a reentry vehicle with arbitrary drag coefficient, mass, and area, and the analog computer circuit for solving these equations in real time is given. Then a method of using several such circuits to compute simultaneously the trajectories of multiple targets with variations in all three initial velocity components as well as variations in ballistic coefficient is presented.
The generating rank of the unitary and symplectic Grassmannians

We prove that the Grassmannian of totally isotropic k-spaces of the polar space associated to the unitary group SU"2"n(F) (n@?N) has generating rank (2nk) when F F"4. We also reprove the main result of Blok (2007) [3], namely that the Grassmannian of totally isotropic k-spaces associated to the symplectic group Sp"2"n(F) has generating rank (2nk)-(2nk-2), when Char(F) 2.
A remark on brane stabilization in brane world

Abstract In this note we discuss dynamical mechanisms for brane stabilization in the brane world context. In particular, we consider supersymmetry preserving brane stabilization, and also brane stabilization accompanied by supersymmetry breaking. These mechanisms are realized in some four dimensional N =1 supersymmetric orientifold models. For illustrative purposes we consider two explicit orientifold models previously constructed by the author [Nucl. Phys. B 535 (1998) 311]. In both of these models branes are stabilized at a finite distance from the orientifold planes. In the first model brane stabilization occurs via supersymmetry preserving non-perturbative gauge dynamics. In the second model supersymmetry is dynamically broken, and brane stabilization is due to an interplay between non-perturbatively generated superpotential and tree-level Kahler potential.
Stable birational equivalence and geometric Chevalley-Warning

We propose a ‘geometric Chevalley-Warning’ conjecture, that is a motivic extension of the Chevalley-Warning theorem in number theory. It is equivalent to a particular case of a recent conjecture of F. Brown and O.Schnetz. In this paper, we show the conjecture is true for linear hyperplane arrangements, quadratic and singular cubic hypersurfaces of any dimension, and cubic surfaces in P. The last section is devoted to verifying the conjecture for certain special kinds of hypersurfaces of any dimension. As a by-product, we obtain information on the Grothendieck classes of the affine ‘Potts model’ hypersurfaces considered in [AM].
Magnetic monopoles, Bogomol'nyi bound and SL(2, Z) invariance in string theory

We show that in heterotic string theory compactified on a six-dimensional torus, the lower bound (Bogomol’nyi bound) on the dyon mass is invariant under the SL(2, ℤ) transformation that interchanges strong and weak coupling limits of the theory. Elementary string excitations are also shown to satisfy this lower bound. Finally, we identify specific monopole solutions that are related via the strong-weak coupling duality transformation to some of the elementary particles saturating the Bogomol’nyi bound, and these monopoles are shown to have the same mass and degeneracy of states as the corresponding elementary particles.
Attrition among families of divorce: patterns in an outpatient psychiatric population.

The accelerated divorce rate has greatly increased the number of children of divorce. In addition, the children and families of divorce are proportionately overrepresented in populations seeking child guidance and psychiatric services. However, the patterns in the use of such services by these families has been unexamined. In our study we find no differences in the use of outpatient psychiatric services between families where both biological parents are present and families of divorce. A closer look at the divorced families reveals that recently divorced mother-headed families more frequently interrupt both the evaluation and treatment phases of clinic contact. Several clinical patterns are described which help explain the finding and it is suggested that the traditional child guidance model may not be the most suitable intervention modality in working with these families.
A Two-Quadrant Transistor Chopper for an Electric Vehicle Drive

A two-quadrant dc-dc transistor converter capable of delivering 400 A motoring current and of generating 200 A braking current is described. The chopper operates from a 108-V dc source (54 lead-acid cells) and supplies the armature current of a separately excited dc machine in an electric vehicle application (3000-lb commuter-type vehicle). The chopper employs high-current transistors specifically developed for the application and power diodes packaged together in power module form. Snubber networks which reduce both turn-on and turn-off device stresses are employed. The interaction of the snubber networks for the motoring and braking transistors is described and design considerations presented. It was found that for these snubbers a minimum on-time and a minimum off-time for the transistors must be maintained to ensure that the transistors' dynamic load lines never enter into the region of forward bias or reversed bias second breakdown. A technique is described which instantaneously detects a transistor failure and initiates the appropriate action in order to prevent machine overcurrent and overtorque. Factors are discussed which are crucial to ensure proper transitions from motoring to braking and to inhibit device power dissipation due to parasitic currents. The selection of a variable-frequency/variable-pulsewidth switching strategy and protection and control techniques unique to high-current transistor choppers are discussed.
The production-theoretic measurement of input price and quantity indices

Abstract This paper extends work by Fisher and Shell (1972) on the production-theoretic treatment of output deflation to the case of input deflation (see also Muellbauer, 1972). Input deflation is examined for a multi-product firm (or sector) in three cases: 1. (a) selling at fixed prices, 2. (b) with monopoly power over some outputs, 3. (c) operating as a perfectly competitive industry but facing downward-sloping demand curves. The latter case is particularly complex, and Paasche and Laspeyres bounds are show not to apply. Issues such as the treatment of quality change (hedonics) are also examined.
A Reconsideration of the Twentieth Century

Robert A. Mundell held his Prize Lecture December 8, 1999, at Aula Magna, Stockholm University. He was presented by Lars E.O. Svensson, Chairman of the Prize Committee.(This abstract was borrowed from another version of this item.)
Stationary solutions of N = 2 supergravity

Abstract We discuss general bosonic stationary configurations of N = 2, D = 4 supergravity coupled to vector multiplets. The requirement of unbroken supersymmetries imposes constraints on the holomorphic symplectic section of the underlying special Kahler manifold. The corresponding solutions of the field equations are completely determined by a set of harmonic functions. As examples we discuss rotating black holes, Taub-NUT and Eguchi-Hanson-like instantons for the STU model. In addition, we discuss, in the static limit, world-sheet instanton corrections to the STU black hole solution, in the neighborhood of a vanishing 4-cycle of the Calabi-Yau manifold. Our procedure is quite general and includes all known black hole solutions that can be embedded into N = 2 supergravity.
The local bifurcation of Ramsey equilibrium

The hypothesis that aggregate fluctuations may represent an endogenous feature of dynamic competitive economies with incomplete markets has been advanced in several papers.1 The role of incomplete markets seems essential for the appearance of cycles in one sector models.2 Becker and Foias (1987) and Woodford (1988a) have pointed out that the elasticity of substitution of the production function plays a fundamental role in the existence of cyclic equilibrium paths. In those papers cycles are generated if the substitutability between capital and labor is not too great. Heterogeneity of households is also a crucial component of their fluctuation theories.
Some multinuclear NMR studies of the macrocyclic effect

Abstract Enthalpies and entropies of complexation were determined for thallium(I) and sodium complexes with several linear and cyclic polyethers in N,N -dimethylformamide and acetonitrile solutions. As usual, the stabilities of the cyclic complexes were considerably higher than those of their linear analogs. No clear cut conclusions could be reached as to entropic or ethalpic nature of the macrocyclic effect.
Synthesis of propane-2,3-diol combinatorial monomers

Abstract Base catalyzed reaction of heterocyclic bases with R-(+)-glycidol gives heteroarylpropane-2,3-diols which are functionalized to the 3-O-dimethoxytrityl-2-O-phosphoramidites. A dimethoxytrityl-glycidol is reacted with alkyl or aryl Grignard reagents and then phosphitylated to yield 1-O-dimethoxytrityl-2-phosphoramidites. These compounds can be used for combinatorial oligomer synthesis.
Sodium Percarbonate: A Convenient Reagent for the Thermal and Sonic Oxidative Cleavage of α-Haloketones

Abstract Sodium percarbonate has been found to be a mild and effective reagent for the oxidative cleavage of α-haloketones to carboxylic acids. Furthermore, the reactions are dramatically accelerated in the presence of ultrasound with significant enhancement in yields.
Energy-efficient connected d-hop dominating sets in wireless sensor networks

In most applications involving wireless sensor networks (WSN), each sensor equipped with a battery collects data in the surrounding area, and forwards it for processing. Since the battery is irreplaceable, many researchers have investigated the issue of extending the network lifetime by reducing the total energy consumption by the network. A possible solution is to construct a backbone of a reasonable size for the network that consumes as little energy as possible. A common approach to construct a backbone for a WSN is to build a set of nodes such that every other node is close to a node in this set. Such a set is known as a dominating set in graph theory. In this paper, we study the problem of assigning minimum total power to a set of nodes in the plane yielding a graph containing a connected d-hop dominating set of bounded size. We prove that this problem is NP-complete. We also introduce several heuristics for this problem and discuss their performance through simulations.
Gaussian conditional independence relations have no finite complete characterization

We show that there can be no finite list of conditional independence relations which can be used to deduce all conditional independence implications among Gaussian random variables. To do this, we construct, for each n>3 a family of n conditional independence statements on n random variables which together imply that X1⫫X2, and such that no subset have this same implication. The proof relies on binomial primary decomposition.
Decarbonylation of some pyrimidine‐5‐carboxaldehydes

In the course of determining the ultraviolet spectra of some 2,4,6-trisubstituted-pyrimidine-5-carboxalde-hydes we discovered the facile loss of the formyl group. The reaction appears to be restricted to pyrimidine-5-carboxaldehydes containing three strongly electron donating substituents. Loss of the formyl group occurs at room temperature only in methanol with large excess of acid. Other alcohols and water fail to afford the decarbonylated product. A suggested pathway for this reaction is offered.
Pin Photodiodes for Radiation Monitoring and Protection in the Babar Silicon Vertex Tracker

We discuss the design, implementation and performance of the radiation monitoring and protection system used by the Silicon Vertex Tracker (SVT) in the BaBar detector. Using 12 reverse-biased PIN photodiodes mounted around the beampipe near the IP, we are able to provide instantaneous radiation dose rates, absorbed dose integrals, and active protection that aborts the circulating beams in the PEP-II storage ring when radiation levels exceed user-defined thresholds. The systems has reliably protected the SVT from excessive radiation damage and has also served as a key diagnostic tool in understanding radiation backgrounds at PEP-II.
Modeling Collisional Cascades in Debris Disks: The Numerical Method

We develop a new numerical algorithm to model collisional cascades in debris disks. Because of the large dynamical range in particle masses, we solve the integro-differential equations describing erosive and catastrophic collisions in a particle-in-a-box approach, while treating the orbital dynamics of the particles in an approximate fashion. We employ a new scheme for describing erosive (cratering) collisions that yields a continuous set of outcomes as a function of colliding masses. We demonstrate the stability and convergence characteristics of our algorithm and compare it with other treatments. We show that incorporating the effects of erosive collisions results in a decay of the particle distribution that is significantly faster than with purely catastrophic collisions.
Lessons From India In Organizational Innovation: A Tale Of Two Heart Hospitals

Recent discussions in health reform circles have pinned great hopes on the prospect of innovation as the solution to the high-cost, inadequate-quality U.S. health system. But U.S. health care institutions—insurers, providers, and specialists—have ceded leadership in innovation to Indian hospitals such as Care Hospital in Hyderabad and the Fortis Hospitals around New Delhi, which have U.S.-trained doctors and can perform open heart surgery for $6,000 (compared to $100,000 in the United States). The Indian success is a window into America’s stalemate with inflating costs and stagnant innovation.
FUZZY SUPERNOVA TEMPLATES. I. CLASSIFICATION

Modern supernova (SN) surveys are now uncovering stellar explosions at rates that far surpass what the world's spectroscopic resources can handle. In order to make full use of these SN data sets, it is necessary to use analysis methods that depend only on the survey photometry. This paper presents two methods for utilizing a set of SN light-curve templates to classify SN objects. In the first case, we present an updated version of the Bayesian Adaptive Template Matching program (BATM). To address some shortcomings of that strictly Bayesian approach, we introduce a method for Supernova Ontology with Fuzzy Templates (SOFT), which utilizes fuzzy set theory for the definition and combination of SN light-curve models. For well-sampled light curves with a modest signal-to-noise ratio (S/N >10), the SOFT method can correctly separate thermonuclear (Type Ia) SNe from core collapse SNe with ≥98% accuracy. In addition, the SOFT method has the potential to classify SNe into sub-types, providing photometric identification of very rare or peculiar explosions. The accuracy and precision of the SOFT method are verified using Monte Carlo simulations as well as real SN light curves from the Sloan Digital Sky Survey and the SuperNova Legacy Survey. In a subsequent paper, the SOFT method is extended to address the problem of parameter estimation, providing estimates of redshift, distance, and host galaxy extinction without any spectroscopy.
Survival of Terrestrial Planets in the Presence of Giant Planet Migration

The presence of "hot Jupiters," Jovian-mass planets with very short orbital periods orbiting nearby main-sequence stars, has been proposed to be primarily due to the orbital migration of planets formed in orbits initially much farther from the parent star. This migration affects the evolution of inner terrestrial planets in these systems. Previous analyses have assumed that no terrestrial planets survive after migration has occurred. We present numerical simulations showing that a significant fraction of terrestrial planets could survive the migration process and possibly return to near circular orbits relatively close to their original positions. A fraction of the final orbits are in the habitable zone, suggesting that planetary systems with close-in giant planets are viable targets for searches for Earth-like habitable planets around other stars.
Negative Index of Refraction and Distributed Bragg Reflectors

CATMAS — Computational and Theoretical Materials Sciences GroupDepartment of Engineering Science and MechanicsPennsylvania State University, University Park, PA 16802–6812ABSTRACT: The Bragg regime shifts when conventional materials in a multilayerdistributed Bragg reﬂector (DBR) are replaced by artiﬁcial materials with the so–called negative index of refraction. This provides an avenue for characterizing thelatter class of materials.Keywords: Distributed Bragg reﬂector, Negative index of refraction
Mild and convenient N-formylation protocol in water-containing solvents

We have realized that N-formylations of free amines of some drug leads can improve PK/PD property of parent molecules without decreasing their biological activities. In order to selectively formylate primary amines of polyfunctional molecules, we have sought a mild and convenient formylation reaction. In our screening of N-formylation of an α-amino acid, L-phenylalanine, none of formylation conditions reported to date yielded the desired HCO-L-Phe-OH with satisfactory yield. N-Formylations of amino acids with HCO2H require the reactions in a water-containing media and suppress polymerization reactions due to the competitive reactions among carboxylic acids. We found that N-formylations of α-amino acids could be achieved with a water-soluble peptide coupling additive, an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl-2-cyano-2-(hydroxyimino)acetate (2), EDCI, and NaHCO3 in water or a mixture of water and DMF system, yielding N-formylated α-amino acids with excellent yields. Moreover, these conditions could selectively formylate primary amines over secondary amines at a controlled temperature. A usefulness of these conditions was demonstrated by selective formylation of daptomycin antibiotic which contains three different amino groups.
What is the largest Einstein radius in the universe

The Einstein radius plays a central role in lens studies as it characterizes the strength of gravitational lensing. In particular, the distribution of Einstein radii near the upper cutoff should probe the probability distribution of the largest mass concentrations in the universe. Adopting a triaxial halo model, we compute expected distributions of large Einstein radii. To assess the cosmic variance, we generate a number of Monte-Carlo realizations of all-sky catalogues of massive clusters. We find that the expected largest Einstein radius in the universe is sensitive to parameters characterizing the cosmological model, especially {sigma}{sub s}: for a source redshift of unity, they are 42{sub -7}{sup +9}, 35{sub -6}{sup +8}, and 54{sub -7}{sup +12} arcseconds (errors denote 1{sigma} cosmic variance), assuming best-fit cosmological parameters of the Wilkinson Microwave Anisotropy Probe five-year (WMAP5), three-year (WMAP3) and one-year (WMAP1) data, respectively. These values are broadly consistent with current observations given their incompleteness. The mass of the largest lens cluster can be as small as {approx} 10{sup 15} M{sub {circle_dot}}. For the same source redshift, we expect in all-sky {approx} 35 (WMAP5), {approx} 15 (WMAP3), and {approx} 150 (WMAP1) clusters that have Einstein radii larger than 2000. For a larger source redshift of 7,more » the largest Einstein radii grow approximately twice as large. While the values of the largest Einstein radii are almost unaffected by the level of the primordial non-Gaussianity currently of interest, the measurement of the abundance of moderately large lens clusters should probe non-Gaussianity competitively with cosmic microwave background experiments, but only if other cosmological parameters are well-measured. These semi-analytic predictions are based on a rather simple representation of clusters, and hence calibrating them with N-body simulations will help to improve the accuracy. We also find that these 'superlens' clusters constitute a highly biased population. For instance, a substantial fraction of these superlens clusters have major axes preferentially aligned with the line-of-sight. As a consequence, the projected mass distributions of the clusters are rounder by an ellipticity of {approx} 0.2 and have {approx} 40%-60% larger concentrations compared with typical clusters with similar redshifts and masses. We argue that the large concentration measured in A1689 is consistent with our model prediction at the 1.2{sigma} level. A combined analysis of several clusters will be needed to see whether or not the observed concentrations conflict with predictions of the at {Lambda}-dominated cold dark matter model.« less
The efficiency of storage management schemes for Ada programs

The efficient implementation of high level languages which support concurrency is imperative, particularly in such application areas as embedded real-time systems. Various storage management schemes have been proposed for the implementation concurrency. In this work, a methodology is presented for evaluating the performance of these schemes including the standard heap, Berry-heap, cactus stack and quantized heap when used for Ada programs. The methodology involves the generation of workload traces from an executing program and the use of simulators of the alternative storage management schemes to produce measures of the performances of the schemes. The performance evaluation metrics used are space, time and the space-time product.
Syntheses and structures of rhodium-osmium clusters derived from the reaction of (μ-H)2Os3(CO)10 with (η5-C5H5)Rh(CO)2

Abstract The reaction between (μ-H) 2 Os 3 (CO) 10 and (η 5 -C 5 H 5 )Rh(CO) 2 in toluene at 90°C produces (η 5 -C 5 H 5 )RhOs 2 (CO) 9 (I) and (μ-H) 2 (η 5 -C 5 H 5 )RhOs 3 (CO) 10 (II), as the principal products while the pentanuclear cluster (μ-H) 2 (η 5 -C 5 H 5 )RhOs 4 (CO) 13 (III) is obtained in low yield. When added hydrogen is present during the reaction, replacement of the cyclopentadienide ligand by toluene occurs and the principal product is (μ-H) 3 (η 6 -C 6 H 5 CH 3 )RhOs 3 (CO) 9 (VI). Also produced in this reaction are (μ-H) 2 (η 5 -C 5 H 5 ) 2 Rh 2 Os 2 (CO) 7 (IV) and cluster II, but in low yields. In benzene in the presence of H 2 , an analogous reaction occurs. The cyclopentadienide ligand is replaced by benzene to give (μ-H) 3 (η 6 -C 6 H 6 )RhOs 3 (CO) 9 (VII) as the main product and clusters II and (μ-H) 4 (η 5 -C 5 H 5 )RhOs 3 (CO) 9 (V) are formed in small yields. Conversion of clusters I and II to clusters IV and V, respectively, was achieved by bubbling H 2 through toluene solutions of I and II at 90°C. Cluster V is moderately unstable in solution, with significant decomposition occurring during the reaction. The molecular structures of clusters II, III, IV, and VII have been determined by single crystal X-ray diffraction studies. Clusters II, IV, and VII have tetrahedral metal cores, while the pentanuclear cluster III has an Os tetrahedral core which is edge bridged by a Rh atom. For compound II: space group P 2 1 / n , a 8.120(3), b 14.932(3), c 16.277(3) A, β 91.29(4)°, V 1972.9 A 3 , Z = 4, mol wt = 1020.73, ρ calcd 3.434 gm cm −3 , and μ calcd 201.5 cm −1 for Mo- K α ; 3885 independent reflections ⩾ 3σ( I ); 4 ⩽ 2θ ⩽ 55° obtained at −35°C; final R f 5.7%, R wf 7.4%. For compound III: space group P 2 1 / c , a 11.134(2), b 16.649(2), c 14.015(2) A, β 109.98(1)°, V 2441.6 A 3 , Z = 4, mol wt = 1294.95, ρ calcd = 2.773 gm cm −3 , and μ calcd 162.6 cm −1 for Mo- K α ; 5695 independent reflections ⩾ 3σ( I ); 4 ⩽ 2θ ⩽ 50° at −30°C; final R f 2.95%, R wf 4.0%. For compound IV: space group P 2 1 / c , a 8.186(3), b 15.651(5), c 15.723(2) A, β 97.32°, V 1998.25 A 3 , Z = 4, mol wt = 914.49, ρ calcd 3.038 gm cm −3 , and μ calcd 143.34 cm −1 for Mo- K α ; 3619 independent reflections ⩾ 3σ( I ); 4 ⩽ 2θ ⩽ 55° at 25°C; final R f 3.3%, R wf 4.5%. For compound VII: space group R , a = b = c = 10.003(4) A, α = β = γ = 92.16(3)°, V = 998.3 A 3 , Z = 2, mol wt = 1006.5, ρ calcd 3.34 gm cm −3 , and μ calcd 214.8 cm −1 Mo- K α ; 3017 independent reflections ⩾ 3σ( I ); 4 ⩽ 2θ ⩽ 50° at 25°C; Final R f 4.4%, R wf 6.3%.
Evolution of Fault Efficiency at Restraining Bends within Wet Kaolin Analog Experiments

Abstract Restraining bends are regions of mechanical inefficiency along strike-slip faults where faults evolve to improve efficiency. Analog experiments using wet kaolin examine the evolution of a variety of restraining bends. Restraining bends with 15° bends continue to slip while systems with greater bends develop new faults. The new faults, which flank the uplifted region, accommodate right-lateral slip when parallel to the plate movement and oblique-slip motion when parallel to the restraining segment. Within the wet kaolin, strain is partitioned into fault slip and off-fault deformation, such as distributed shear and uplift. The wet kaolin produces restraining bend deformation patterns, fault sequence and mechanical efficiency similar to dry sand experiments and natural restraining bends. The propagation of new faults in the wet kaolin improves the mechanical efficiency of the fault system by increasing the ratio of fault slip to off-fault deformation. Local inefficiencies, such as linkage of faults via a sharp kink, do not affect the overall increase in efficiency of the linked fault system. Furthermore, wider restraining bend stepovers have lower mechanical efficiency than close stepovers, but the difference in mechanical efficiency decreases as faults grow and link up around the restraining bends. This study demonstrates that restraining bend fault systems evolve toward greater mechanical efficiency.
Exploring the evolution of complexity in signaling networks

Signaling networks are exemplified by systems as diverse as biological cells, economic markets, and the Web. After a discussion of some general characteristics of signaling networks, this article explores the adaptive evolution of complexity in a simple model of a signaling network. The article closes with a discussion of broader questions concerning the evolution of signaling networks.
Transformations of unsaturated acyclic sugars into enantiomerically pure norbornene derivatives

Abstract The C 7 acyclic unsaturated-sugar ester 1 , derived from l -arabinose, and its enantiomer serve as convenient dieneophiles for chirality transfer for synthesis of optically pure carbocyclic derivatives through cycloaddition reactions. Reaction of 1 with cyclopentadiene may be controlled to give preparative access to the 5,6-disubstituted norbornene adducts 4a , 5a , and 7a , according to the conditions used. The distribution of the four possible isomeric products from this cycloaddition was quantitated, and the effect of substitutional variation on the precursor dienophile 1 was also examined. Adducts 4a and 5a were transformed into such substituted carbocycles of known absolute configuration as the methyl esters ( 11 and 12 ) of norbornene (bicyclo[2.2.1]hept-2-ene)-6-carboxylic acid and nortricyclane (tricyclo[2.2.1.0 2,6 ]heptane)-3-carboxylic acid in optically pure form, specifically through decarbonylation reactions using RhCl(PPh 3 ) 3 (Wilkinson's complex) and [Rh(dppp) 2 ]Cl[dppp = Ph 2 P(CH 2 ) 3 PPh 2 ]. The optical purity of 12 was established by the use of a chiral lanthanide shift-reagent.
Electroforming of large mirrors

Thin metal mirrors are prime candidates for space applications, because of their high thermal conductivity, low weight, and ability to withstand vibration during launch. Of all the fabrication processes, at the present state of the art, electroforming appears the most suitable for producing accurate, thin, metal mirrors with satisfactory mechanical and physical properties. Great strides were made over the past two years in precision electroforming. These are described along with General Electric’s spincasting process for the fabrication of masters.
IMMUNOASSAY OF ENDOGENOUS PLASMA INSULIN IN MAN

For years investigators have sought an assay for insulin which would combine virtually absolute specificity with a high degree of sensitivity, sufficiently exquisite for measurement of the minute insulin concentrations usually present in the circulation. Methods in use recently depend on the ability of insulin to exert an effect on the metabolism of glucose in vivo or in excised muscle or adipose tissue. Thus, the insulin concentration in plasma has been estimated: a) from the degree of hypoglycemia produced in hypophysectomized, adrenalectomized, alloxan-diabetic rats (1); b) from the augmentation of glucose uptake by isolated rat hemidiaphragm (2); or c) from the increased oxidation of glucose-1-C14 by the rat epididymal fat pad (3). Since there have been reports indicating the presence, in plasma, of inhibitors of insulin action (4) and of noninsulin substances capable of inducing an insulin-like effect (5,6), these procedures, while yielding interesting information regarding the effects of various plasmas on glucose metabolism in tissues, are of doubtful specificity for the measurement of insulin per se (5).
Zero-curvature solutions of the one-dimensional Schrodinger equation

We discuss special k = [2m(E - V(x))/2]1/2 = 0 (i.e. zero-curvature) solutions of the one-dimensional Schr?dinger equation in several model systems which have been used as idealized versions of various quantum well structures. We consider infinite well plus Dirac delta function cases (where E = V(x) = 0) and piecewise-constant potentials, such as asymmetric infinite wells (where E = V(x) = V0 > 0). We also construct supersymmetric partner potentials for several of the zero-energy solutions in these cases. One application of zero-curvature solutions in the infinite well plus ?-function case is the construction of 'designer' wavefunctions, namely zero-energy wavefunctions of essentially arbitrary shape, obtained through the proper placement and choice of strength of the ?-functions.
Against wisdom: the social politics of anger and aging

Abstract Focusing on two books key to the cultural history of aging in America in the twentieth century—G. Stanley Hall's Senescence: The Last Half of Life [Hall, G. S. (1922, rpt. 1972). Senescence: the last half of life. New York: Arno Press] and Betty Friedan's The Fountain of Age [Friedan, B. (1993). The fountain of age. New York: Simon and Schuster], this essay explores: (1) the cultural reflex of invoking wisdom as the special strength of the old and (2) the strategy of using anger to call attention to ageism. “Against Wisdom” argues that it is difficult, if not virtually impossible, to envision a productive future for the elderly through the joint cultural building blocks of wisdom and anger. A manifesto of sorts, the essay calls for a moratorium on wisdom and suggests that stories of a vitalizing anger at being marginalized because old be told and circulated, and concludes with a story from Barbara Macdonald's Look Me in the Eye: Old Women, Aging, and Ageism.
Point-like instantons on K3 orbifolds

The map between the moduli space of F-theory (or type 11 string) compactifications and heterotic string compactifications can be considerably simplified by using “stable degenerations”. We discuss how this method applies to both the E8 × E8 and the Spin(32)/Z2 heterotic string. As a simple application of the method we derive some basic properties of the non-perturbative physics of collections of E8 or Spin(32)/Z2 point-like instantons sitting at ADE singularities on a K3 surface.
Towards an active network architecture

Active networks allow their users to inject customized programs into the nodes of the network. An extreme case, in which we are most interested, replaces packets with "capsules" -- program fragments that are executed at each network router/switch they traverse.Active architectures permit a massive increase in the sophistication of the computation that is performed within the network. They will enable new applications, especially those based on application-specific multicast, information fusion, and other services that leverage network-based computation and storage. Furthermore, they will accelerate the pace of innovation by decoupling network services from the underlying hardware and allowing new services to be loaded into the infrastructure on demand.In this paper, we describe our vision of an active network architecture, outline our approach to its design, and survey the technologies that can be brought to bear on its implementation. We propose that the research community mount a joint effort to develop and deploy a wide area ActiveNet.
Synthesis and sulfatase inhibitory activities of (E)- and (Z)-4-hydroxytamoxifen sulfamates.

Abstract We report the development of ( E )- and ( Z )-4-hydroxytamoxifen sulfamates as estrone sulfatase inhibitors, potential therapeutic agents for the treatment of breast cancer. Both compounds competitively inhibit estrone sulfatase isolated from rat liver with apparent K i of 35.9 μM for ( E )-4-hydroxytamoxifen sulfamate and an apparent K i of > 500 μ M for the (Z) isomer. We report the development of ( E )-and ( Z )-4-hydroxytamoxifen sulfamates as estrone sulfatase inhibitors, potential therapeutic agents for the treatment of breast cancer. Both compounds competitively inhibit rat liver estrone sulfatase, with an apparent K i of 35.9 μM for ( E )-4-hydroxytamoxifen sulfamate and an apparent K i of > 500 μ M for the (Z) isomer.
Modeling of Shock Tunnel Aeroheating Data on the Mars Science Laboratory Aeroshell

A series of shots are run in the T5 shock tunnel at California Institute of Technology to measure heating levels on a 70 blunt cone at angle of attack in an environment representative of the Mars Science Laboratory entry. Twenty shots are obtained in CO 2 over a range of enthalpies and pressures chosen to span the laminar and turbulent flow regimes. The data indicate that the lee side turbulent heating augmentation predicted by flight simulations is valid and must be accounted for during the design of the thermal protection system. Computational fluid dynamic simulations are generally in good agreement with the laminar data when employing a supercatalytic wall model, whereas turbulent simulations are in reasonable agreement when a noncatalytic wall model is used. The reasons for this discrepancy are unknown at this time. The turbulent heating augmentation is shown to be inversely related to freestream enthalpy. Changes in angle of attack between 11 and 16 are shown to have minimal impact on measured and computed heating. A transition criterion based on momentum thickness Reynolds number, analogous to that used in flight predictions, predicts onset with reasonable accuracy, although transition is observed to occur later than the current design criterion indicates.
Mirror transitions and the Batyrev-Borisov construction

We consider examples of extremal transitions between families of Calabi-Yau complete intersection threefolds in toric varieties, which are induced by toric embeddings of one toric variety into the other. We show that the toric map induced by the linear dual of the embedding induces a birational morphism between the mirror Calabi-Yau families, and in one case show that it can be extended to the full mirror transition between mirror families.
In-situ stresses in low-permeability, nonmarine rocks

In-situ stress measurements have been performed over a 2,500-ft (760-m) interval in the nonmarine section of the Cretaceous Mesaverde in the Piceance basin in Colorado. These measurements included 52 hydraulic fracture measurements of the minimum in-situ stress and 22 anelastic strain recovery (ASR) measurements. Stress data obtained in sandstones, shales, mudstones, siltstones, and coals show the effect of lithology on the magnitudes of the stresses.