cssi/SciSciGPT-SciSciNet huggingface dataset:
Eigensystem of an L 2-perturbed harmonic oscillator is an unconditional basis

For any complex valued Lp-function b(x), 2 ≤ p < ∞, or L∞-function with the norm ‖b↾L∞‖ < 1, the spectrum of a perturbed harmonic oscillator operator L = −d2/dx2 + x2 + b(x) in L2(ℝ1) is discrete and eventually simple. Its SEAF (system of eigen- and associated functions) is an unconditional basis in L2(ℝ).
Magnetically Controlled Spasmodic Accretion during Star Formation. I. Formulation of the Problem and Method of Solution

We formulate the problem of the late accretion phase of the evolution of an isothermal magnetic disk surrounding a forming star. The evolution is described by the six-fluid MHD equations, accounting for the presence of neutrals, atomic and molecular ions, electrons, and neutral, positively, and negatively charged grains. Only the electron fluid is assumed to be attached to the magnetic field, in order to investigate the effect of the detachment of the ions from the magnetic field lines that begins at densities as low as 108 cm-3. The "central sink approximation" is used to circumvent the problem of describing the evolution inside the opaque central region for densities greater than 1011 cm-3. In this way, the structure and evolution of the isothermal disk surrounding the forming star can be studied at late times without having to implement the numerically costly radiative transfer required by the physics of the opaque core. The mass and magnetic flux accumulating in the forming star are calculated, as are their effects on the structure & evolution of the surrounding disk. The numerical method of solution first uses an adaptive grid and later, after a central region a few AU in radius becomes opaque, switches to a stationary but nonuniform grid with a central sink cell. It also involves an implicit time integrator, an advective difference scheme that possesses the transportive property, a second-order difference approximation of forces inside a cell, an integral approximation of the gravitational and magnetic fields, and tensor artificial viscosity that permits an accurate investigation of the formation and evolution of shocks in the neutral fluid.
Doping-induced inhomogeneity in high-Tc superconductors ☆

Doping and disorder are inseparable in the superconducting cuprates. Assuming the simplest possible disordered doping, we construct a semiphenomenological model and analyze its experimental consequences. Among the affected experimental quantities are the ARPES spectra and thermodynamic properties. From our model we make a prediction for the width of the local superconducting gap distribution with the only experimentally unknown parameter being the superconducting correlation length. Thus, our model provides a direct way of determining the superconducting correlation length from a known experimental gap distribution.
Overview of the second text retrieval conference (TREC-2)

Abstract The second Text Retrieval Conference (TREC-2) was held in August, 1993, and was attended by about 150 people involved in 31 participating groups. The goal of the conference was to bring research groups together to discuss their work on a new large test collection. There was a large variation of retrieval techniques reported on, including methods using automatic thesaurii, sophisticated term weighting, natural language techniques, relevance feedback, and advanced pattern matching. As results had been run through a common evaluation package, groups were able to compare the effectiveness of different techniques, and discuss how differences between the systems affected performance.
Knoevenagel-like condensations with highly stabilized active methylene compounds

Abstract Bis (phenylsulfonyl) methane, nonafluorobutylsulfonylacetonitrile or heptadecafluorooctylsulfonyl acetonitrile could be condensed with the strained ketone cyclopenta [2,1-b; 4,3-b′] dithiophen-4-one ( 1 ) to afford the corresponding α, β unsaturated sulfones using a combination of a Grignard reagent of the methylene compound, TiCl 4 -activation of the ketone and N-methylmorpholine as base for the final deprotonation-elimination step.
Tandem ring-closing metathesis reaction with a ruthenium catalyst containing a N-heterocyclic ligand

The highly active catalyst 2 was used in tandem RCM to make molecules with various ring systems containing α,β-unsaturated carbonyl compounds.
Failure of the Regge approach in two dimensional quantum gravity

Abstract Regge's method for regularizing euclidean quantum gravity is applied to two dimensional gravity. We use two different strategies to simulate the Regge path integral at a fixed value of the total area: A standard Metropolis simulation combined with a histogramming method and a direct simulation using a Hybrid Monte Carlo algorithm. Using topologies with genus zero and two and a scale invariant integration measure, we show that the Regge method does not reproduce the value of the string susceptibility of the continuum model. We show that the string susceptibility depends strongly on the choice of the measure in the path integral. We argue that the failure of the Regge approach is due to spurious contributions of reparametrization degrees of freedom to the path integral.
HEAVY ION THEORY: QCD AND MATTER IN EXTREMIS

Nuclear matter is predicted to undergo a phase transition and become a plasma of quarks and gluons (QGP) at high temperature and density. Recent experimental results from high-energy heavy-ion collisions at the Relativistic Heavy-ion Collider (RHIC) indicate the production of a strongly interacting quark-gluon matter with fluid-like properties. I will discuss some expected features of QCD at high temperature and density, theoretical interpretations of experimental observations and challenges in unraveling some of the basic properties of dense matter in the strongly interacting regime.
Obesity Before Age 30 Years and Risk of Advanced Prostate Cancer

Editorial Comment: These 2 articles provide insight into the potential for testosterone to increase the risk of prostate cancer. This topic is of great interest because of the recent marketing of testosterone replacement as the “fountain of youth” for many of our elderly patients. Although there has been no consensus on the relationship between testosterone levels and prostate cancer risks, Parsons et al point out that virtually all prior studies used single measurements. Instead, in this study from the Baltimore Longitudinal Study of Aging they evaluated serial androgen measurements over a period as long as 40 years and were able to show that high circulating levels of free testosterone were associated with a significant increase in the risk of prostate cancer. Furthermore, they showed that men with low testosterone levels had a decreased risk. This observation is confirmed in the study by Swerdlow et al that looked at men with Klinefelter syndrome, a condition in which men are exposed to low levels of androgen throughout their life. This study showed that their risk of developing prostate cancer was reduced by 80%. These observations raise concerns about the safety of using testosterone replacement. Until true benefits have been demonstrated in elderly men this practice should be avoided, or if undertaken in men who are clearly hypogonadal, they should undergo a prostate biopsy before treatment to make certain they don’t have cancer, and after therapy is initiated testosterone levels should be carefully monitored.
Rhodium‐Catalyzed Asymmetric 1,4‐Additions, in Water at Room Temperature, with In‐Flask Catalyst Recycling

Using the newly introduced designer surfactant polyethyleneglycol ubiquinol sebacate (PQS), as the platform for micellar catalysis, nonracemic BINAP has been covalently attached and rhodium(I) inserted to form PQS-BINAP-Rh. This species, the first example of a nonracemically-ligated transition metal catalyst-tethered amphiphile, can be utilized for Rh-catalyzed asymmetric conjugate addition reactions of arylboronic acids to acyclic and cyclic enones. These are performed in water at room temperature, while the catalyst can be recycled without its removal from water in the reaction vessel.
Probing strings from the sky

We discuss several possibilities of probing string theory through cosmology, e.g., the imprints of short distance physics on CMB anisotropies, the signatures of brane inflationary models, and the cosmological constraints on D-matter.
Accelerator Development for Heavy Ion Fusion

Accelerator technology development is presented for heavy ion drivers used in inertial-confinement fusion. The program includes construction of low-velocity "test-bed" accelerator facilities, development of analytical and experimental techniques to characterize ion-beam behavior, and the study of ion-beam energy deposition.
Synthesis of propargylic ethers via Lewis-acid mediated nucleophilic substitution of propargylic esters

Direct displacement of propargvlic esters is reported. 10 mol% of TiCl4 were used to carry out this novel, nucleophilic substitution.
Social Learning in Recurring Games

Abstract In a recurring game, a stage game is played sequentially by different groups of players. Each group receives publicly available information about the play of earlier groups. Not knowing the population distribution of player types (representing individual preferences and behavior), society members start with a prior probability distribution over a set of possible type-distributions. Late groups update their beliefs by considering the public information regarding the play of earlier groups. We study the limit beliefs and play of late groups and the relationships to the true (realized) type-distribution and equilibria of the true Bayesian stage game.Journal of Economic LiteratureClassification Numbers: C72, C73, D83.
Measuring the impact of health policies using Internet search patterns: the case of abortion.

Background: Internet search patterns have emerged as a novel data source for monitoring infectious disease trends. We propose that these data can also be used more broadly to study the impact of health policies across different regions in a more efficient and timely manner. Methods: As a test use case, we studied the relationships between abortion-related search volume, local abortion rates, and local abortion policies available for study. Results: Our initial integrative analysis found that, both in the US and internationally, the volume of Internet searches for abortion is inversely proportional to local abortion rates and directly proportional to local restrictions on abortion. Conclusion: These findings are consistent with published evidence that local restrictions on abortion lead individuals to seek abortion services outside of their area. Further validation of these methods has the potential to produce a timely, complementary data source for studying the effects of health policies.
The Eilenberg–Watts theorem over schemes

Abstract We study obstructions to a direct limit preserving right exact functor F between categories of quasi-coherent sheaves on schemes being isomorphic to tensoring with a bimodule. When the domain scheme is affine, or if F is exact, all obstructions vanish and we recover the Eilenberg–Watts Theorem. This result is crucial to the proof that the noncommutative Hirzebruch surfaces constructed in C. Ingalls, D. Patrick (2002) [6] are noncommutative P 1 -bundles in the sense of M. Van den Bergh [10] .
Low-Light-Level Optical Interactions with Rubidium Vapor in a Photonic Band-Gap Fiber

We create a significant population of Rubidium atoms inside a hollow-core photonic band-gap fiber, which we use for performing nonlinear optical interactions at very low light levels.
A FUNCTOR CONVERTING EQUIVARIANT HOMOLOGY TO HOMOTOPY

In this paper, an equivariant version of the classical Dold-Thom theorem is proved. Let G be a finite group, X a G-space, and k a covariant coefficient system onG. Then a topological abelian group GX GF k is constructed by the coend construction. For a G-CW complex X, it is proved
In situ imaging of the conducting filament in a silicon oxide resistive switch

The nature of the conducting filaments in many resistive switching systems has been elusive. Through in situ transmission electron microscopy, we image the real-time formation and evolution of the filament in a silicon oxide resistive switch. The electroforming process is revealed to involve the local enrichment of silicon from the silicon oxide matrix. Semi-metallic silicon nanocrystals with structural variations from the conventional diamond cubic form of silicon are observed, which likely accounts for the conduction in the filament. The growth and shrinkage of the silicon nanocrystals in response to different electrical stimuli show energetically viable transition processes in the silicon forms, offering evidence for the switching mechanism. The study here also provides insights into the electrical breakdown process in silicon oxide layers, which are ubiquitous in a host of electronic devices.
Boundary sine-Gordon interactions at the free fermion point

Abstract We study bosonization of the sine-Gordon theory in the presence of boundary interactions at the free fermion point. In this way we obtain the boundary S-matrix as a function of physical parameters in the boundary sine-Gordon Lagrangian. The boundary S-matrix can be matched onto the solution of Ghoshal and Zamolodchikov, thereby relating the formal parameters in the latter solution to the physical parameters in the lagrangian.
Hans Duistermaat’s contributions to Poisson geometry

Hans Duistermaat was scheduled to lecture in the 2010 School on Poisson Geometry at IMPA, but passed away suddenly. This is a record of a talk I gave at the 2010 Conference on Poisson Geometry (the week after the School) to share some of my memories of him and to give a brief assessment of his impact on the subject.
NONLINEAR ELASTICITY AND THERMODYNAMICS OF GRANULAR MATERIALS

The elastic properties of granular materials can be enormously nonlinear as compared with the properties of non-porous materials. Experiments on isotropic compression of a granular assembly of spheres show that the shear μ, and bulk k, moduli vary with the confining pressure faster than the 1/3 power law predicted by Hertz–Mindlin elasticity theory. Moreover, the ratio between the experimental bulk and shear moduli is found to be constant but with a value larger than the theoretical prediction. Numerical simulations resolve the question as to whether the problem lies with the treatment of the grain-grain contact or with the elastic framework. We find that the problem lies principally with the latter; the affine assumption (which underlies the elastic formulation) is found to be valid for k but to breakdown seriously for μ. This explains why the experimental and numerical values of μ(p) are much smaller than the elastic predictions. In this paper we review recent progress on the understanding of this problem based on microscopic simulations, elasticity theory and more innovative ideas such as jamming, fragility and thermodynamics of granular materials.
Reparameterisation invariance constraints on heavy particle effective field theories

Abstract Since fields in the heavy quark effective theory are described by both a velocity and a residual momentum, there is redundancy in the theory: small shifts in velocity may be absorbed into a redefinition of the residual momentum. We demonstrate that this trivial reparameterisation invariance has non-trivial consequences: it relates coefficients of terms of different orders in the 1 m expansion and requires linear combinations of these operators to be multiplicatively renormalised. For example, the operator − 2 2m in the effective lagrangian has zero anomalous dimension, coefficient one, and does not receive any non-perturbative contributions from matching conditions. We also demonstrate that this invariance severely restricts the forms of operators which may appear in chiral lagrangians for heavy particles.
CHARACTERISING SUBSPACES OF BANACH SPACES WITH A SCHAUDER BASIS HAVING THE SHIFT PROPERTY

We give an intrinsic characterisation of the separable reflexive Banach spaces that embed into separable reflexive spaces with an unconditional basis all of whose normalised block sequences with the same growth rate are equivalent. This uses methods of E. Odell and T. Schlumprecht. 1. THE SHIFT PROPERTY We consider in this paper a property of Schauder bases that has come up on sev- eral occasions since the first construction of a truly non-classical Banach space by B. S. Tsirelson in 1974 (11). It is a weakening of the property of perfect homogeneity, which replaces the condition all normalised block bases are equivalent with the weaker all normalised block bases with the same growth rate are equivalent, and is satisfied by bases constructed along the lines of the Tsirelson basis, including the standard bases for the Tsirelson space and its dual. To motivate our study and in order to fix ideas, in the following result we sum up a number of conditions that have been studied at various occasions in the literature and that can all be seen to be reformulations of the aforementioned property. Though I know of no single reference for the proof of the equivalence, parts of it are implicit in J. Lindenstrauss and L. Tzafriri's paper (7) and the paper by P. G. Casazza, W. B. Johnson and L. Tzafriri (2). Moreover, any idea needed for the proof can be found in,
Low-Symmetry Uranyl Pyrophosphate Cage Clusters

The combination of uranyl, peroxide, and pyrophosphate in aqueous solution results in the self-assembly of highly complex clusters containing 45 uranyl bipyramids and 23 pyrophosphate groups. These clusters are built from three basic structural units, and are highly unusual because they completely lack symmetry. They provide a window into the complex chemistry of evolving cluster topologies under the conditions of their formation.
The origin of Pluto's peculiar orbit

THE origin of Pluto's unusual orbit—the most eccentric and inclined of all the planets—remains a mystery. The orbits of Pluto and Neptune overlap, but close approaches of these two planets are prevented by the existence of a resonance condition1: Pluto's orbital period is exactly 3/2 that of Neptune, which ensures that the conjunctions always occur near Pluto's aphelion. Long-term orbit integrations2–5 have uncovered other subtle resonances and near-resonances, and indicate that Pluto's orbit is chaotic yet remains macroscopically stable over billion-year timescales. A suggestion4 that the orbit may have evolved purely by chaotic dynamics appears unlikely in light of recent orbital stability studies6, unless one appeals to a well-timed collision to place Pluto in its stable orbit19. Here I show that Pluto could have acquired its current orbit during the late stages of planetary accretion, when the jovian planets underwent significant orbital migration as a result of encounters with residual planetesimals7. As Neptune moved outwards, a small body like Pluto in an initially circular orbit could have been captured into the 3:2 resonance, following which its orbital eccentricity would rise rapidly to its current Neptune-crossing value.
Optically Probing and Controlling the Spin State of a Single Quantum Dot

A quantum dot could be used as an optically addressed quantum bit. I will discuss our efforts to optically probe and control the spin in individual quantum dots charged with a single electron.
Synthesis, crystal structure, and nonlinear optical properties of Li6CuB4O10: a congruently melting compound with isolated [CuB4O10]6- units.

Single crystals of Li6CuB4O10 have been synthesized, and its crystal structure has been determined. Li6CuB4O10 crystallizes in the non-centrosymmetric triclinic space group P1 (No. 1). The structur...
Airflow and heat transfer in double skin facades

Abstract Airflow and heat transfer simulation was conducted for a DSF system equipped with a venetian blind, using computational fluid dynamics (CFD) with RNG turbulence model, for a three-level combination of slat tilt angle and blind position. The CFD prediction was validated using experimental data collected for a mechanically ventilated DSF equipped with venetian blinds. The predicted trends in glass and blind surface temperatures of the CFD model are compared well with the experimental measurements. The present study indicates that the presence of venetian blinds influences the surface heat transfer coefficients (SHTCs), the temperature and the air distribution in the DSF system. For the cases considered, the changes in the position of the blinds (outer, middle, and inner) have more effect on the distribution of temperature, velocity, and SHTCs compared to the changes in the slat angles ( θ = 0°, 45°, 90°).
The Influence of Nuclear Radiation on Pool-Boiling Heat Transfer to Liquid Helium

Pool-boiling experiments were performed in helium from high purity copper which had been exposed to various amounts of fast neutron radiation. The residual effects of the radiation influenced the pool boiling in two ways: First by decreasing the thermal conductivity of the copper substrate; and second by inducing residual radioactivity in the copper. The changes in the conductivity influenced the unsteady heat conduction process associated with nucleate boiling. The residual radiation from the copper augmented the bubble nucleation in the superheated helium in a manner similar to a bubble chamber. The relative magnitudes of the two effects were influenced by surface smoothness.
Governing equations for weakly ionized plasma flowfields of aerospace vehicles

A generalized set of conservative equations for simulating the flowfield in a hypersonic weakly ionized gas flows is presented. Additional numerical and physical complexities associated with the plasma state are identified and discussed, including the influence of external and space charge fields and the nonequilibrium coupling of reactive and nonreactive collisions. A restricted set of equations is then employed to simulate and analyze the flowfield of an air plasma generated by associative ionization. With use of a seven-species air model, details of the plasma flowfields are presented and compared with available experiments. Refined estimates of dissociation products, which are the precursors to the ionization reaction, are obtained. Specific attention is given to limiting forms of the electron diffusion coefficient and the influence of vibration-dissociation coupling. Details of the chemical reactions in the flowfield influencing the elastic and inelastic collisional energy transfer are reported to highlight the more important species and reaction mechanisms.
Adrenocortical Neoplasms: Role of Prognostic Markers MIB-1, P53, and RB

Differentiation between benign and malignant adrenocortical neoplasms is made using a combination of clinical and pathologic parameters. Despite these parameters, it is still difficult to predict the biologic potential of some tumors. Forty adrenocortical lesions, including 10 hyperplasias, 10 ad
Economic geography: the great half-century

The paper examines the intellectual history of economic geography over the last 50 years. Three major episodes of research activity are considered: (a) the spatial analysis and regional science movement of the 1960s; (b) the turn to political economic (especially Marxian) approaches in the 1970s; and (c) the intensification of interest in regional‐global interactions since about the mid-1980s. Two minor interludes are also briefly examined; these are represented by behavioural geography and the so-called localities debate. It is suggested that the course of economic geography over the last half-century can best be understood by reference to the sociology of knowledge, i.e., a contextualised but reasoned description of those contextualised but reasoned descriptions that constitute scholarly practice.
Primate evolution: Evidence from the fossil record, comparative morphology, and molecular biology

Our understanding of primate evolution is ultimately based on patterns of phyletic relationship and morphological change documented in the fossil record. Stratophenetic interpretation of living and fossil primates yields an objective alternative to the arbitrary scala naturae assumed implicitly in traditional comparative biology. Fossils provide an outline of primate history constraining comparative analyses incorporating taxa and morphological characteristics not represented in the fossil record. Extant taxa without known prehistoric relatives may be interpolated into this outline using deductive cladistic analysis of morphological characteristics and overall molecular similarity. Cladistic analysis provides a method for evaluating the relative strength of stratophenetic links between taxa. The phyletic node connecting Anthropoidea-Adapoidea-Lemuroidea is analyzed here as an example: the link between Eocene Adapoidea and primitive Anthropoidea appears stronger than that between Adapoidea and Lemuroidea because it is based on shared-derived rather than shared-primitive characteristics. Full integration of molecular results with morphological information requires a better understanding of rates of molecular change over geological time. Rates of molecular evolution can be studied using paleontologically documented divergence times for Prosimii-Anthropoidea (ca. 55 m.y.B.P.), Platyrrhini-Catarrhini (ca. 40 m.y.B.P.), and Hominoidea-Cercopithecoidea (ca. 25 m.y.B.P.). Immunological distances combined with these divergence times indicate that primate albumin, widely used as a molecular clock in primatology, has evolved nonlinearly over geological time. A nonlinear albumin clock yields divergence times of about 9 million years before present for humans and chimpanzees, and about 13 million years before present for humans and orangutans (compared with 4 m.y.B.P. and 7 m.y.B.P., respectively, based on a linear albumin clock). Apparent slowing of albumin evolution over time remains to be fully explained. Other proteins and nucleic acids may provide better clocks. Cladistic analysis of morphological characteristics and comparative study of molecular structure, interpreted in the context of the fossil record, promise to contribute to a more complete understanding of primate evolution.
Using adaptive optics to enhance Michelson interferometry

The implementation of adaptive wave-front compensation techniques offers the potential to improve the detection sensitivity of a Michelson stellar interferometer. The improvement obtained depends on many factors, including the completeness of the wave-front corrections. Calculations based on simple theory are presented that predict the shot-noise-limited sensitivity enhancement as measured in limiting stellar visual magnitudes for adaptive optical systems offering varying degrees of spatial compensation. Even low-order wave-front corrections are shown to yield significant improvement in detection thresholds.
Synthesis and catalytic properties of metal nanoparticles: Size, shape, support, composition, and oxidation state effects

Exciting new opportunities are emerging in the field of catalysis based on nanotechnology approaches. A new understanding and mastery of catalysis could have broad societal impacts, since about 80% of the processes in the chemical industry depend on catalysts to work efficiently. Efforts in surface science have led to the discovery of new heterogeneous catalysts, however, until recently the only way to develop new or improved catalysts was by empirical testing in trial-and-error experiments. This time-consuming and costly procedure is now rapidly being replaced by rational design methods that utilize fundamental knowledge of catalysts at the nanoscale. The advent of nanoscience and nanotechnology is providing the ability to create controlled structures and geometries to investigate and optimize a broad range of catalytic processes. As a result, researchers are obtaining fundamental insight into key features that influence the activity, selectivity, and lifetime of nanocatalysts. This review article examines several new findings as well as current challenges in the field of nanoparticle based catalysis, including the role played by the particle structure and morphology (size and shape), its chemical composition and oxidation state, and the effect of the cluster support.
The Chemical Development of the Commercial Route to Sildenafil: A Case History

This paper is a case history of the chemical development of sildenafil which covers various aspects of work in chemical development namely: route selection, scale-up issues, the development of an efficient synthesis with high throughput, process safety, and environmental issues. Interesting chemical points include improved methods of preparing pyrazolo[4,3-d]pyrimidines and the unusual isolation of an intermediate as its double salt (10). The potential dangers of nitrating pyrazole-5-carboxylic acids which are activated to a decarboxylation reaction are discussed.
Probing the Properties of Neutron Stars with Type I X-Ray Bursts

The increase in spin frequency as the burning atmospheres of type I X-ray bursts cool provides a strong constraint on the radius of the underlying neutron star. If the change in spin frequency is due to a change in the thickness of the atmosphere, the radius of the star must exceed 3GM/c2 for any equation of state and approximately 3.5GM/c2 for most physically reasonable equations of state. This constraint arises because the direction of the Coriolis force for radial motion reverses for R < G/c2(M + I/R2). Furthermore, the marked change in the magnitude of the Coriolis force near compact stars provides a straightforward explanation for why the frequency of the quickly rotating bursters shifts by the same amount as the slow rotators: they are slightly more massive, 1.6 M☉ versus 1.4 M☉.
Corporate governance metrics for Asian companies: are they reliable indicators of corporate performance?

As more investors have bought shares in Asian companies, global interest in these firms' corporate governance has soared. Firms like Institutional Shareholder Services have begun to rate Asian firms' corporate governance, assigning them "Corporate Governance Quotients" (CGQ). Some research suggests that companies with higher CGQs deliver better shareholder returns for investors. The first section of this paper examines whether this positive relation holds true in the Asian market and considers the implications of our findings for Asian managers. The second section raises some more general questions about the value and viability of corporate governance ratings and identifies some dangers associated with corporate governance rating systems.
Momentum in Residential Real Estate

This paper examines whether there is return momentum in residential real estate in the U.S. Case and Shiller (American economic review 79(1):128–137, 1989) document evidence of positive return correlation in four U.S. cities. Similar to Jegadeesh and Titman’s (Journal of finance 56:699–720, 1993) stock market momentum paper, we construct long-short zero cost investment portfolios from more than 380 metropolitan areas based on their lagged returns. Our results show that momentum of returns in the U.S. residential housing is statistically significant and economically meaningful during our 1983 to 2008 sample period. On average, zero cost investment portfolios that buy past winning housing markets and short sell past losing markets earn up to 8.92% annually. Our results are robust to different sub-periods and more pronounced in the Northeast and West regions. While zero cost portfolios of residential real estate indices is not a tradable strategy, the implications of our results can be useful for builders, potential home owners, mortgage originators and traders of real estate options.
Design of FIR precoders and equalizers for broadband MIMO wireless channels with power constraints

This paper examines the optimum design of FIR precoders or equalizers for multiple-input multiple-output (MIMO) frequency-selective wireless channels. For the case of a left-coprime FIR channel, which arises generically when the number nT of transmit antennas is larger than the number nR of receive antennas, the Bezout matrix identity can be employed to design an FIR MIMO precoder that equalizes exactly the channel at the transmitter. Similarly, for a right-coprime FIR channel, the Bezout identity yields an FIR zero-forcing MIMO equalizer. Unfortunately, Bezout precoders usually increase the transmit power, and Bezout equalizers tend to amplify the noise power. To overcome this problem, we describe in this paper a convex optimization technique for the optimal synthesis of MIMO FIR precoders subject to transmit power constraints, and of MIMO FIR equalizers with output noise power constraints. The synthesis problem reduces to the minimization of a quadratic objective function under convex quadratic inequality constraints, so it can be solved by employing Lagrangian duality. Instead of solving the primal problem, we solve the lower-dimensional dual problem for the Lagrange multipliers. When an FIR MIMO precoder has already been selected, we also describe a technique for adding a vector shaping sequence to the transmitted signal in order to reduce the transmit power. The selection of effective shaping sequences requires a search over a trellis of large dimensionality, which can be accomplished suboptimally by employing reduced-complexity search techniques.
The relationship of the Laplacian gauge to the Landau gauge

The Laplacian gauge for gauge group SU(N) is discussed in perturbation theory. It is shown that to the lowest non-trivial order (O(g1), configurations in the Laplacian automatically satisfy the (finite difference) Landau gauge condition. Laplacian gauge fixed configurations are examined numerically and it is seen that to O(g2) they do not remain in the Landau gauge.
Origins of Eccentric Extrasolar Planets: Testing the Planet-Planet Scattering Model

In planetary systems with two or more giant planets, dynamical instabilities can lead to collisions or ejections through strong planet-planet scattering. Previous studies for initial conditions with two equal-mass planets revealed two discrepancies between the results of simulations and the observed orbits of exoplanets: potentially frequent collisions between giant planets and a narrow distribution of final eccentricities. We show that simulations with two unequal-mass planets starting on nearly circular orbits predict fewer collisions and a broader range of final eccentricities. Thus, the two-planet scattering model can reproduce the observed eccentricities with a plausible distribution of planet mass ratios. The model also predicts a maximum eccentricity of 0.8, independent of the distribution of planet mass ratios, provided that both planets are initially placed on nearly circular orbits. This compares favorably with observations and will be tested by future planet discoveries. Moreover, the combination of planet-planet scattering and tidal circularization may explain the existence of some giant planets with very short period orbits. Orbital migration due to planet scattering could play an important role in explaining the distribution of orbital periods found by radial velocity surveys. We also reexamine and discuss various possible correlations between eccentricities and other properties of exoplanets. We find that radial velocity observations are consistent with planet eccentricities being correlated with the ratio of the escape velocity from the planet's surface relative to the escape velocity from the host star at the planet's location. We demonstrate that the observed distribution of planet masses, periods, and eccentricities can provide constraints for models of planet formation and evolution.
Pricing effects in Fannie Mae agency bonds

As a government-sponsored enterprise, Fannie Mae enjoys certain advantages over other firms. The extent of these advantages, while widely discussed, have not yet been fully quantified. This paper empirically examines the returns to Fannie Mae general obligation bonds under the assumptions of the Arbitrage Pricing Theory. The model provides an explicit method for estimating the risk premium on Fannie Mae bonds. The results indicate that liquidity and tax effects are important in explaining the returns to Fannie Mae bonds. The results also indicate that the market does not incorporate changes in the riskiness of the mortgage market into the returns on Fannie Mae bonds. The results provide support for the contention that Fannie Mae, as a government sponsored enterprise, enjoys a significant advantage over other firms in the capital market.
BPS one-branes in five dimensions

In a recent paper, we studied the scalar fields of the five dimensional hypermultiplets using the method of symplectic covariance. For static spherically symmetric backgrounds, we showed that exactly two possibilities exist and detailed one of them. In this paper, we present the second case: Bogomol'nyi–Prasad–Sommerfeld one-branes carrying charge under the hypermultiplets. We find an explicitly symplectic solution of the fields in this background and derive the conditions required for a full spacetime understanding.
The Biosynthetic Gene Cluster of Pantocin A Provides Insights into Biosynthesis and a Tool for Screening

The biosynthetic gene cluster of pantocin A provides insights into biosynthesis and a tool for screening
Allocation and leakage in regional cap-and-trade markets for CO2

Abstract The allocation or assignment of the emissions permits is one of the most contentious elements of the design of cap-and-trade systems In this paper we develop a detailed representation of the U.S. western electricity market to assess the potential impacts of various permit allocation proposals. Several proposals involve the “updating” of allocations, where the allocation is tied to the ongoing output, or input use, of plants. These allocation proposals are designed with the goals of limiting the pass-through of carbon costs to product prices, mitigating leakage, and of mitigating the costs to high-emissions firms. However, allocation updating can also inflate permit prices, thereby limiting the benefits of such schemes to high emissions firms.
Production and control of ion-cyclotron instabilities in the high latitude ionosphere by high power radio waves

Abstract The possible generation and suppression of ion-cyclotron waves in a collisional plasma by external high power electromagnetic (EM) waves with frequency close to the local upper-hybrid frequency is considered. It is shown that the ion cyclotron instability can be destabilized (stabilized) for ω 0 UH (ω 0 > ω UH ), where ω 0 is the pump frequency of the EM wave. The results are applied to naturally occurring ion-cyclotron instabilities in the high latitude ionosphere.
Synthesis, Structure, and Bonding of Two Lanthanum Indium Germanides with Novel Structures and Properties.

The new tetragonal phases La3In4Ge and La3InGe are obtained from high-temperature reactions of the elements in welded Ta followed by annealing. The structures of both were established by single-crystal X-ray diffraction in tetragonal space group I4/mcm (Z = 4 and 16, a = 8.5165(3) and 12.3083(2) A, c = 11.9024(4) and 16.0776(4) A, respectively). La3In4Ge contains layers or slabs of three-connected indium built of puckered 8-rings and 4-rings, or of squashed tetrahedra (“butterflies”) interlinked at all vertices, and these are separated by layers of La and isolated Ge. The phase is deficient of being a Zintl phase by three electrons per formula unit and is better described in terms of an alternate optimized and delocalized bonding picture and an open-shell metallic behavior for the In slabs. The more complex La3InGe, isostructural with Gd3Ga2, is also layered. This phase contains pairs of mixed-occupancy (0.75 In, 0.25 Ge) sites separated by 3.020 A, as well as isolated In and Ge atoms. The former appear t...
Suppression of experimental allergic neuritis in rats by prior immunization with nerve in saline.

Rats given nerve in saline intraperitoneally failed to develop allergic neuritis when challenged with nerve in adjuvant 2 weeks later. The serum of protected rats prevented sensitized lymph node cells, from rats immunized only with nerve in adjuvant, from demyelinating rat peripheral nerve cultures.
Far-Ultraviolet Spectroscopy of Star-forming Regions in Nearby Galaxies: Stellar Populations and Abundance Indicators*

We present Far Ultraviolet Spectroscopic Explorer spectroscopy and supporting data for star-forming regions in nearby galaxies, to examine their massive-star content and explore the use of abundance and population indicators in this spectral range for high-redshift galaxies. New far-ultraviolet spectra are shown for four bright H II regions in M33 (NGC 588, 592, 595, and 604), the H II region NGC 5461 in M101, and the starburst nucleus of NGC 7714, supplemented by the very low metallicity galaxy I Zw 18. In each case we see strong Milky Way absorption systems from H2, but intrinsic absorption within each galaxy is weak or undetectable, perhaps because of the "UV bias" in which reddened stars that lie behind molecular-rich areas are also heavily reddened. We see striking changes in the stellar wind lines from these populations with metallicity, suggesting that C II, C III, C IV, N II, N III, and P V lines are potential tracers of stellar metallicity in star-forming galaxies. Three of these relations—involving N IV, C III, and P V—are nearly linear over the range from O/H = 0.05–0.8 solar. The major difference in continuum shapes among these systems is that the giant H II complex NGC 604 has a stronger continuum shortward of 950 A than any other object in this sample. Small number statistics would likely go in the other direction; we favor this as the result of a discrete star-forming event ≈3 Myr ago, as suggested by previous studies of its stellar population.
Private Investment, Public Aid and Endogenous Divergence in the Evolution of Urban Neighborhoods

This paper offers a novel explanation for urban blight and endogenous divergence in the overall quality and wealth of neighborhoods and simultaneously derives the salient features of actual urban renewal and other aid programs from optimizing government behavior based on collective public preferences. These features appear when the objective of such public aid programs is to restore the ex ante distribution of wealth or property values within a blighted neighborhood, while equilibria exhibiting deficient levels of private investment and blight itself can arise when residents accurately anticipate the potential provision of public aid to an affected neighborhood and ex ante investment in private insurance diminishes neighborhood eligibility for such aid. Examples of antipodal equilibria in which urban renewal programs entirely crowd out local private investment or in which neighborhood residents invest in efficient levels of private mitigation illustrate these results, which stand in direct contrast to both traditional explanations of urban blight and to the new “social-interaction” models of neighborhood divergence.
Computer design and optimization of cryogenic refrigeration systems

Abstract This paper describes the design and optimization of a cryogenic refrigerator using the LBL computer program GEOTHM. This computer program has been used extensively to design and optimize geothermal power plants and power cycles of other types. GEOTHM can calculate the thermodynamics of a wide variety of cycles including refrigeration cycles. GEOTHM has an optimizer which permits single step multi-parameter optimization of a thermodynamic cycle. A refrigeration cycle may be optimized for minimum cost refrigeration, or maximum thermodynamic performance using up to 55 optimizable parameters. The use of the optimizer in GEOTHM is demonstrated on two liquid nitrogen refrigeration cycles which are optimized for minimum refrigeration cost and minimum input power.
BINOMIAL ARMA COUNT SERIES FROM RENEWAL PROCESSES

This paper describes a new method for generating stationary integervalued time series from renewal processes. We prove that if the lifetime distribution of renewal processes is nonlattice and the probability generating function is rational, then the generated time series satisfy causal and invertible ARMA type stochastic dierence equations. The result provides an easy method for generating integer-valued time series with ARMA type autocovariance functions. Examples of generating binomial ARMA(p;p 1) series from lifetime distributions with constant hazard rates after lag p are given as an illustration.
On rational belief equilibria

We study equilibria in which agent's belief are rational in the sense of Kurz [1994]. The market is formulated by specifying a stochastic demand function and a continuum of producers, each with a quadratic cost function who must select their output before knowing prices. Holding Rational Beliefs about future prices, producers maximize expected profits. In a Rational Belief Equilibrium (RBE) agents select diverse forecast functions but each one is rational in the sense that it is based on a theory which cannot be rejected by the data. It is shown that there exists a continuum of RBE's and they could entail very different patterns of time series for the economy and consequently different aggregate levels of longterm volatility. Since the model contains exogenously specified random variables, the difference in the level of long-term volatility of prices among the different RBE's arises endogenously as an “amplification” of the volatility of exogenous variables. The paper derives exact bounds on the possible levels of such “amplification.”
S-T connectivity on digraphs with a known stationary distribution

We present a deterministic logspace algorithm for solving S-T Connectivity on directed graphs if: (i) we are given a stationary distribution of the random walk on the graph in which both of the input vertices s and t have nonnegligible probability mass and (ii) the random walk which starts at the source vertex s has polynomial mixing time. This result generalizes the recent deterministic logspace algorithm for S-T Connectivity on undirected graphs [Reingold, 2008]. It identifies knowledge of the stationary distribution as the gap between the S-T Connectivity problems we know how to solve in logspace (L) and those that capture all of randomized logspace (RL).
Induced Resonance Electron Cyclotron (IREC) Quasi-Optical Maser.

Abstract In this paper we analyze an induced resonance electron cyclotron (IREC) quasi-optical maser configuration. This configuration has the unique features of being highly efficient and at the same time relatively insensitive to the detrimental effects of poor beam quality. A system of nonlinear coupled orbit equations, describing the dynamics of electrons in a spatially varying external magnetic field and the electromagnetic field of a steady state oscillator, are derived and analyzed. We show that with the proper choice for the index of refraction, the high frequency cyclotron interaction can be made insensitive to a beam energy spread. The interaction can, however, be sensitive to the beam's pitch angle spread. The necessary conditions on beam quality for high efficiency operation are derived and shown to be in good agreement with our numerical solutions. Furthermore, we show that by appropriately tapering the magnetic field an induced resonance condition can be achieved which results in high interaction efficiencies. It is anticipated that an efficient, high power millimeter, submillimeter and infrared radiation source can be realized with the IREC quasi-optical maser configuration.
Photochemical Heck benzylation of styrenes catalyzed by Na[FeCp(CO)2]

Abstract Iron-catalyzed Heck coupling of benzyl chlorides and styrenes proceeds under photochemical conditions using the well-known anionic complex, [FeCp(CO) 2 ] - (Fp − ), as a catalyst. The reaction likely proceeds through the established S N 2 mechanism for Fp − alkylation, followed by styrene migratory insertion and β-hydride elimination steps that are enabled by photochemical CO dissociation.