cssi/SciSciGPT-SciSciNet huggingface dataset:
Thyroid abnormalities following neck irradiation for Hodgkin's disease

Thyroid function and scans were evaluated in fifty disease-free patients 2 to 16 years after receiving neck irradiation for the treatment of Hodgkin's disease. Twenty-five of 50 patients had abnormal thyroid studies: eight were hypothyroid, two were hypothyroid and had abnormal scans, and fifteen had abnormal scans. Of the 15 patients with abnormal scans, one had an isolated elevation of TSH (thyroid stimulating hormone) and one developed exophthalmos. These data, obtained within a relatively short follow-up period, indicate that morphologic and functional abnormalities of the thyroid gland are not uncommon in patients who have received irradiation to the thyroid gland in the course of treatment for Hodgkin's disease. There is need for continuous reevaluation of the thyroid status in such patients.
Status of Design Criteria for Predicting Departure Characteristics and Spin Susceptibility

This paper presents the status on efforts made during the past few years to develop and correlate various criteria for predicting full-scale aircraft departure characteristics and spin susceptibility. The criteria discussed are Dynamic Directional Stability, the Lateral Control Departure Parameter (LCDP), and a relatively new criterion known as the Beta Plus Delta Axis Stability Indicator. Data acquired on several operational aircraft and aircraft under development are presented. Correlation is based primarily on free-flight model test results and the interpretation of these criteria relative to predicting full-scale aircraft departure characteristics and spin susceptibility is discussed.
Image Enhancement: A Data Dependent Systems Approach

A new image enhancement scheme based on a mathematical model obtained by data dependent systems (DDS) approach is described in this paper. A separable 2-D AR model is fitted to the image. Analysis of this model leads to the identification of modes corresponding to dominant physical features. Other intrinsic modes, inherent to the image, are highly damped and constitute difficult-to-interpret local image behavior. Although exerting a minor influence on the image intensities, they hinder a clear perception of the image. In order to enhance the image, these modes must be filtered out. ARMA image enhancement filters are formed using the major inherent modes. Residuals, the part of the image not modeled by this ARMA filter, comprise the enhanced image. This approach can also be used to selectively enhance the desired image features. Examples illustrating clear enhancement of a real image, with natural degradations created by shadows and other artifacts as well as artificially added noise, are given.
Synthesis and reactivity of open-chain and cyclic 2-cyano zinc and copper organometallics

Abstract Various open-chain and cyclic β-cyano zinc and copper organometallics can be prepared by the reaction of the corresponding organic halides with zinc and subsequent transmetalation with CuCN · 2 LiCl. They react in fair to good yields with various organic electrophiles (enones, allylic bromides and benzoyl chloride) affording highly functionalized nitriles. High diastereoselectivities have been observed in coupling reactions with the cyclic 2-cyano organocopper derivatives. The x-ray structure of cyanoethylzinc iodide is also reported.
Work Incentives and Salary Distributions in Major League Baseball

Baseball fans complain about the extraordinary sums of money team owners spend to sign free agents. The size of these superstar contracts may not only anger veterans on the team, but adversely affect overall team performance (Wiseman, F., & Chatterjee, S. (2003). Team Payroll and Team Performance in Major League Baseball: 1985–2002. Economics Bulletin, 1(2), 1–10). This note reexamines the relationship between payroll and performance in Major League Baseball (MLB) from 2001 to 2005. Specifically, is there still empirical support for the Wiseman and Chatterjee claim that the more equally this payroll is distributed among team members, the better the on-field performance of the team. To determine whether or not the structure of compensation has any effect on performance, Gini coefficients were calculated for all 30 teams in MLB from 2001 to 2005. Player salary data are from http://rodneyfort.com/PHSportsEcon/Common/ OtherData/MLBPayroll/MLBPayrolls.html. The larger a team’s Gini coefficient, the more unequal is the salary distribution. A Gini coefficient of 1 would represent complete inequality (one player earns all of the team’s payroll) and a Gini coefficient of 0 would represent complete equality of the salary distribution. For each of the five years, the team’s win percentage was first regressed on the team’s Gini ratio. The regression results for 2005 were as follows (t-values in parentheses):
GENETIC ALGORITHMS AND THE ANDREWS–CURTIS CONJECTURE

The Andrews–Curtis conjecture claims that every balanced presentation of the trivial group can be transformed into the trivial presentation by a finite sequence of "elementary transformations" which are Nielsen transformations together with an arbitrary conjugation of a relator. It is believed that the Andrews–Curtis conjecture is false; however, not so many possible counterexamples are known. It is not a trivial matter to verify whether the conjecture holds for a given balanced presentation or not. The purpose of this paper is to describe some nondeterministic methods, called Genetic Algorithms, designed to test the validity of the Andrews–Curtis conjecture. Using such algorithm we have been able to prove that all known (to us) balanced presentations of the trivial group where the total length of the relators is at most 12 satisfy the conjecture. In particular, the Andrews–Curtis conjecture holds for the presentation which was one of the well known potential counterexamples.
Alcohol inversion of 17β-steroids

Abstract Inversion of 17β-steroids has been accomplished using a modified Mitsunobu protocol in which 4-nitrobenzoic acid is employed as the acidic component. Excellent yields of inverted product were obtained for a number of representative steroid families including estrogens, equilenins, and androgens. Application of this methodology to the synthesis of 17α-dihydroequilenin is described.
Synthesis of new dipyridotetraazapentalenes

Abstract The new heteroaromatic compounds, dipyridotetraazapentalenes 3–5, were synthesized in two steps from readily available triazolopyridines 6 and 10. N-Arylation of 6 and 10 followed by subsequent reductive cyclization of the N-(nitropyridyl)-triazolopyridines with triethylphosphite in toluene afforded 3, 4 and 5, respectively, in good yields. Nitration of 3 afforded the new energetic tetranitrotetraazapentalene derivative 15 in 58% yield.
A formalism for the systematic treatment of rapidity logarithms in Quantum Field Theory

Many observables in QCD rely upon the resummation of perturbation theory to retain predictive power. Resummation follows after one factorizes the cross section into the relevant modes. The class of observables which are sensitive to soft recoil effects are particularly challenging to factorize and resum since they involve rapidity logarithms. Such observables include: transverse momentum distributions at p T much less then the high energy scattering scale, jet broadening, exclusive hadroproduction and decay, as well as the Sudakov form factor. In this paper we will present a formalism which allows one to factorize and resum the perturbative series for such observables in a systematic fashion through the notion of a “rapidity renormalization group”. That is, a Collin-Soper like equation is realized as a renormalization group equation, but has a more universal applicability to observables beyond the traditional transverse momentum dependent parton distribution functions (TMDPDFs) and the Sudakov form factor. This formalism has the feature that it allows one to track the (non-standard) scheme dependence which is inherent in any scenario where one performs a resummation of rapidity divergences. We present a pedagogical introduction to the formalism by applying it to the well-known massive Sudakov form factor. The formalism is then used to study observables of current interest. A factorization theorem for the transverse momentum distribution of Higgs production is presented along with the result for the resummed cross section at NLL. Our formalism allows one to define gauge invariant TMDPDFs which are independent of both the hard scattering amplitude and the soft function, i.e. they are universal. We present details of the factorization and re- summation of the jet broadening cross section including a renormalization in p⊥ space. We furthermore show how to regulate and renormalize exclusive processes which are plagued by endpoint singularities in such a way as to allow for a consistent resummation.
Maximum robustness and surgery of frames in finite dimensions

Abstract We consider frames in a finite-dimensional Hilbert space H n where frames are exactly the spanning sets of the vector space. We present a method to determine the maximum robustness of a frame. We present results on tight subframes and surgery of frames. We also answer the question of when length surgery resulting in a tight frame set for H n is possible.
Complete Parallax and Proper Motion Solutions For Halo Binary-Lens Microlensing Events

A major problem in the interpretation of microlensing events is that the only measured quantity, the Einstein timescale tE, is a degenerate combination of the three quantities one would like to know: the mass, distance, and speed of the lens. This degeneracy can be partly broken by measuring either a parallax or a proper motion, and can be completely broken by measuring both. Proper motions can easily be measured for caustic-crossing binary-lens events. Here we examine the possibility (first discussed by Hardy & Walker) that one could also measure a parallax for some of these events by comparing the light curves of the caustic crossing as seen from two observatories on Earth. We derive analytic expressions for the signal-to-noise ratio of the parallax measurement in terms of the characteristics of the source and the geometry of the event. For Galactic halo binary lenses seen toward the LMC, the light curve is delayed from one continent to another by a seemingly minuscule 15 s (compared to tE ~40 days). However, this is sufficient to cause a difference in magnification on the order of 10%. To actually extract complete parallax information (as opposed to merely detecting the effect) requires observations from three noncollinear observatories. Parallaxes cannot be measured for binary lenses in the LMC, but they can be measured for Galactic halo binary lenses seen toward M31. Robust measurements are possible for disk binary lenses seen toward the Galactic bulge, but are difficult for bulge binary lenses.
The perception of simulated materials

Numerically modeling the interaction of light with materials is an essential step in generating realistic synthetic images. While there have been many studies of how people perceive physical materials, very little work has been done that facilitates efficient numerical modeling. Perceptual experiments and guidelines are needed for material measurement, specification and rendering. For measurement, many devices and methods have been developed for capturing spectral, directional and spatial variations of light/material interactions, but no guidelines exist for the accuracy required. For specification, only very preliminary work has been done to find meaningful parameters for users to search for and to select materials in software systems. For rendering, insight is needed on the perceptual impact of material models when combined with global illumination methods.
Oxygen vacancy defects in tantalum pentoxide: a density functional study

First principles total energy calculations were performed in order to characterize O vacancy defects in Ta2O5. A simplified version of the crystalline orthorhombic phase of Ta2O5 was used in this study. Results indicate that O vacancies in Ta2O5 can be broadly classified based on their location in the lattice. One type of vacancy (occupying the 'in-plane' sites) displays deep or mid gap occupied states, and shallow unoccupied states, while a second type (occupying 'cap' sites) results in shallow occupied states. For a wide range of local Fermi level or chemical potential, the neutral and +2 charged states of the in-plane type vacancy and the +2 charge state of the cap type vacancy are found to be most stable.
Organocatalytic vinyl and Friedel-Crafts alkylations with trifluoroborate salts.

Herein we report the first use of vinyl and heteroaryl trifluoroborate salts as viable substrates for amine-catalyzed conjugate additions. The application of LUMO-lowering iminium catalysis has enabled the highly regio- and enantioselective 1,4-addition of rationally designed trifluoroborate salt nucleophiles to α,β-unsaturated aldehydes. Imidazolidinone 2•HCl was found to catalyze the addition of various BF3K-derived heteroaryl and vinyl species to a range of enals with excellent levels of enantioselectivity. Importantly, the use of these salts can enable nontraditional regiocontrol as part of a Friedel−Crafts pathway. Boronic acids can also be employed as viable π-nucleophiles for these asymmetric conjugate additions provided that in situ activation to the corresponding boronate species is accomplished. While BF3K salts are routinely employed in transition metal catalysis, to our knowledge, this is the first use of this activation group for organic catalysis or Friedel−Crafts alkylations.
Tax structure and public sector growth

Abstract It has been hypothesized that a jurisdiction's tax structure exerts an indipendent effect upon the growth of its public sector. We test this hypothesis by examining the relationship between the growth of state general expenditure and the elasticity of tax revenues with respect to income. The work takes advantage of a very careful set of income elasticities for the personal income and sales tax systems for each state, for every year from 1978 to 1983. The main conclusion is that the data do not support the notion that the form of the tax structure exerts an independent effect on public sector growth.
A Model Problem for Conformal Parameterizations of the Einstein Constraint Equations

We study the conformal and conformal thin sandwich (CTS) methods as candidates for parameterizing the set vacuum initial data for the Cauchy problem of general relativity. To this end we consider a small family of symmetric conformal data. Within this family we obtain an existence result so long as the mean curvature has constant sign. When the mean curvature changes sign we find that solutions either do not exist, or they are not unique. In some cases solutions are shown to be non-unique. Moreover, the theory for mean curvatures with changing sign is shown to be extremely sensitive with respect to the value of a coupling constant in the Einstein constraint equations.
Beating cancer in multiple ways using nanogold

Gold nanoparticles possess a unique combination of properties which allow them to act as highly multifunctional anti-cancer agents (X. H. Huang, P. K. Jain, I. H. El-Sayed and M. A. El-Sayed, Nanomedicine, 2007, 2, 681-693; P. Ghosh, G. Han, M. De, C. K. Kim and V. M. Rotello, Adv. Drug Delivery Rev., 2008, 60, 1307-1315; S. Lal, S. E. Clare and N. J. Halas, Acc. Chem. Res., 2008, 41, 1842-1851; D. A. Giljohann, D. S. Seferos, W. L. Daniel, M. D. Massich, P. C. Patel and C. A. Mirkin, Angew. Chem., Int. Ed., 2010, 49, 3280-3294). Not only can they be used as targeted contrast agents for photothermal cancer therapy, they can serve as scaffolds for increasingly potent cancer drug delivery, as transfection agents for selective gene therapy, and as intrinsic antineoplastic agents. This tutorial review will highlight some of the many forms and recent applications of these gold nanoparticle conjugates by our lab and others, as well as their rational design and physiologic interactions.
Mutated Ptpn11 alters leukemic stem cell frequency and reduces the sensitivity of acute myeloid leukemia cells to Mcl1 inhibition

PTPN11 encodes the Shp2 non-receptor protein-tyrosine phosphatase implicated in several signaling pathways. Activating mutations in Shp2 are commonly associated with juvenile myelomonocytic leukemia but are not as well defined in other neoplasms. Here we report that Shp2 mutations occur in human acute myeloid leukemia (AML) at a rate of 6.6% (6/91) in the ECOG E1900 data set. We examined the role of mutated Shp2 in leukemias harboring MLL translocations, which co-occur in human AML. The hyperactive Shp2E76K mutant, commonly observed in leukemia patients, significantly accelerated MLL-AF9-mediated leukemogenesis in vivo. Shp2E76K increased leukemic stem cell frequency and affords MLL-AF9 leukemic cells IL3 cytokine hypersensitivity. As Shp2 is reported to regulate anti-apoptotic genes, we investigated Bcl2, Bcl-xL and Mcl1 expression in MLL-AF9 leukemic cells with and without Shp2E76K. Although the Bcl2 family of genes was upregulated in Shp2E76K cells, Mcl1 showed the highest upregulation in MLL-AF9 cells in response to Shp2E76K. Indeed, expression of Mcl1 in MLL-AF9 cells phenocopies expression of Shp2E76K, suggesting Shp2 mutations cooperate through activation of anti-apoptotic genes. Finally, we show Shp2E76K mutations reduce sensitivity of AML cells to small-molecule-mediated Mcl1 inhibition, suggesting reduced efficacy of drugs targeting MCL1 in patients with hyperactive Shp2.
Effect of thickness on the unsteady aerodynamics of closely coupled oscillating airfoils

A vortex panel method is presented for the solution of incompressible unsteady aerodynamic problems for airfoils with finite thickness. The accuracy and robustness of the method is demonstrated through comparisons with the existing numerical data and independent test cases. Also, through numerous examples, the flexibility of this method in handling different types of trailing-edge shapes and multiple interfering geometries is shown. furthermore, the method is used to analyse the effects of airfoil thickness on aerodynamic coefficients of multi-element or multiple airfoils. It is shown that, although the influence of thickness is negligible for single element airfoil, it can be profound for closely coupled airfoils and slotted flaps.
Multiphoton ionization of xenon in the vuv regime

In a recent experiment at the vuv free-electron laser facility at DESY in Hamburg, the generation of multiply charged ions in a gas of atomic xenon was observed. This paper develops a theoretical description of the multiphoton ionization of xenon and its ions. The numerical results lend support to the view that the experimental observation may be interpreted in terms of the nonlinear absorption of several vuv photons. The method rests on the Hartree-Fock-Slater independent-particle model. The multiphoton physics is treated within a Floquet scheme. The continuum problem of the photoelectron is solved using a complex absorbing potential. Rate equations for the ionic populations are integrated to take into account the temporal structure of the individual vuv laser pulses. The effect of the spatial profile of the free-electron laser beam on the distribution of xenon charge states is included. An Auger-type many-electron mechanism may play a role in the vuv multiphoton ionization of xenon ions.
Pyrrole-2-carboxylic Acid as a Ligand for the Cu-Catalyzed Reactions of Primary Anilines with Aryl Halides

Pyrrole 2-carboxylic acid (L5) was found to be an effective ligand for the Cu-catalyzed monoarylation of anilines with aryl iodides and bromides. Under the reported conditions (10% CuI/20% L5/DMSO/K3PO4/80−100 °C/20−24 h), a variety of useful functional groups were tolerated, and moderate to good yields of the diaryl amine products were obtained.
Unsafe Rear-End Collision Avoidance in Alzheimer's Disease

Drivers with cognitive impairment are at increased odds for vehicular crashes. Rear-end collisions (REC) are among the most common crash types. We tested REC avoidance in 61 drivers with mild Alzheimer's disease (AD) and 115 elderly controls using a high-fidelity interactive driving simulator. After a segment of uneventful driving, each driver suddenly encountered a lead vehicle stopped at an intersection, creating the potential for a collision with lead vehicle or with another vehicle following closely behind the driver. Eighty-nine percent of drivers with AD had unsafe outcomes, either an REC or an risky avoidance behavior (defined as slowing down abruptly or prematurely, or swerving out of the traffic lane) compared to 65% of controls (P = 0.0007). Crash rates were similar in AD (5%) and controls (3%), yet a greater proportion of drivers with AD slowed down abruptly (70% vs. 37%, P < 0.0001) or prematurely (66% vs. 45%, P = 0.0115). Abrupt slowing increased the odds of being struck from behind by the following vehicle (P = 0.0262). Unsafe outcomes were predicted by tests of visual perception, attention, memory, visuospatial/constructional abilities, and executive functions, as well as vehicular control measures during an uneventful driving segment. Drivers with AD had difficulty responding to driving conditions that pose a hazard for a REC. Some cognitive and visual tests were predictive of unsafe outcomes even after adjusting for disease status.
Aspergillamides A and B: Modified cytotoxic tripeptides produced by a marine fungus of the genus Aspergillus

Abstract Two isomeric linear peptides, aspergillamides A and B (1, 2), were isolated from the mycelium of a cultured marine fungus of the genus Aspergillus. The producing strain (designated CNC-120), was obtained from a saline lake sediment sample collected from Acklins Island, the Bahamas. The structures of the new peptides were elucidated using comprehensive 2D NMR methods. At 25°C, in both acetone and dimethylsulfoxide, aspergillamide A exists as a 1:1 mixture of trans- and cis-amide rotational isomers (1a and 1b). Under identical conditions, aspergillamide B is predominantly in the cis-amide form. The absolute stereochemistries of the amino acids in aspergillamide A were assigned as L by hydrolysis and comparison with commercial standards. Aspergillamide A showed modest in vitro cytotoxicity [IC50 = 16 μg/ml) toward the human colon carcinoma cell line HCT-116.
Iodine-promoted decomposition of 1-aryl-3,3-dialkyltriazenes: A mild method for the synthesis of aryl iodides

Abstract Iodine promoted decomposition of 1-aryl-3,3-dialkyltriazenes in organic solvents is shown to give high yields of the corresponding aryl iodides under extremely mild conditions. The presence of iodine greatly accelerates the reaction in both iodoalkanes as well as in non-iodinated solvents.
Fees Paid to Audit Firms, Accrual Choices, and Corporate Governance

We examine the relation between the fees paid to auditors for audit and non-audit services, and the choice of accrual measures for a large sample of firms. Using our pooled sample, we find that the ratio of non-audit fees to total fees has a positive relation with the absolute value of accruals similar to Frankel, Johnson, and Nelson [2002]. However, using latent class mixture models to identify clusters of firms with a homogenous regression structure reveals that this positive association only occurs for about 8.5% of the sample. In contrast to the fee ratio results, we find consistent evidence of a negative relation between the level of fees (both audit and non-audit) paid to auditors and accruals (i.e., higher fees are associated with smaller accruals). The latent class analysis also indicates that this negative relation is strongest for client firms with weak governance. Overall, our results are most consistent with auditor behavior being constrained by the reputation effects associated with allowing clients to engage in unusual accrual choices.
THE FIRST TURBULENT COMBUSTION

ABSTRACT The first turbulent combustion arises in a hot-big-bang cosmological model (Gibson, 2004) where nonlinear exothermic turbulence permitted by quantum mechanics, general relativity, multidimensional superstring theory, and fluid mechanics cascades from Planck to strong-force freeze-out scales with gravity balancing turbulent inertial-vortex forces. Interactions between Planck scale spinning and non-spinning black holes produce high Reynolds number turbulence and temperature mixing with huge Reynolds stresses driving the rapid inflation of space. Kolmogorovian turbulent temperature patterns are fossilized as strong-force exponential inflation stretches them beyond the scale of causal connection ct where c is light speed and t is time. Fossil temperature turbulence patterns seed nucleosynthesis, and then hydro-gravitational structure formation in the plasma epoch, (Gibson, 1996, 2000). Evidence about formation mechanisms is preserved by cosmic microwave background (CMB) temperature anisotropies. CMB ...
Nonlocal invariants in index theory

In its original form, the Atiyah-Singer Index Theorem equates two global quantities of a closed manifold, one analytic (the index of an elliptic operator) and one topological (a characteristic number). Because it relates invariants from different branches of mathematics, the Index Theorem has many applications and extensions to differential geometry, K-theory, mathematical physics, and other fields. This report focuses on advances in geometric aspects of index theory. For operators naturally associated to a Riemannian metric on a closed manifold, the topological side of the Index Theorem can often be expressed as the integral of local (i.e. pointwise) curvature expression. We will first discuss these local refinements in §1, which arise naturally in heat equation proofs of the Index Theorem. In §§2,3, we discuss further developments in index theory which lead to spectral invariants, the eta invariant and the determinant of an elliptic operator, that are definitely nonlocal. Finally, in §4 we point out some recent connections among these nonlocal invariants and classical index theory.
Expectations for the Hard X-ray Continuum and Gamma-ray Line Fluxes from the Type Ia supernova SN 2014J in M82

The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the 56Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior "X-ray" the bulk debris field in direct fashion, and do not depend on the ofttimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of ~3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last ~30 yr. In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the literature. The model set, containing as it does deflagration, delayed detonation, merger detonation, pulsational delayed detonation, and sub-Chandrasekhar helium detonation models, collectively spans a wide range of properties, and hence signatures. We provide a brief discussion of various diagnostics (with examples), but importantly make the spectral and line results available electronically to aid in the interpretation of the anticipated data.
GaAs-waveguide-based optical neural network device architecture

We propose a monolithic implementation of a feed-forward neural network in AlGaAs/GaAs waveguide material with a Wannier-Stark superlattice in the core. Adjustable weights are applied with the use of voltage-controlled below-bandgap intensity modulators. Nonlinear thresholding is performed with the use of a saturable absorber component. A 2-to-1 single neuron device was fabricated by integrating two 25 dB/mm modulators and a 25 dB nonlinear switch. The device performed with an output/input range ratio of 25 dB using two 780 nm laser diodes.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Giants and dwarfs meet in the middle

The discovery of two remarkable new objects by astronomers has blurred the distinction between stars and planets. It also raises hopes of finding planetary systems like our own in the near future.
Intermolecular C-N addition of amides and S-N addition of sulfinamides to arynes.

An efficient, mild, transition-metal-free method has been developed for the intermolecular C−N σ-bond addition of amides and S−N σ-bond addition of sulfinamides to arynes to form one C−C bond and one heteroatom−carbon bond in one step at room temperature. Evidence for a stepwise mechanism is provided.
On the Dynamical Stability of the Solar System

A long-term numerical integration of the classical Newtonian approximation to the planetary orbital motions of the full solar system (Sun + eight planets), spanning 20 Gyr, was performed. The results showed no severe instability arising over this time interval. Subsequently, utilizing a bifurcation method described by Jacques Laskar, two numerical experiments were performed with the goal of determining dynamically allowed evolutions for the solar system in which the planetary orbits become unstable. The experiments yielded one evolution in which Mercury falls onto the Sun at ~1.261 Gyr from now, and another in which Mercury and Venus collide in ~862 Myr. In the latter solution, as a result of Mercury's unstable behavior, Mars was ejected from the solar system at 822 Myr. We have performed a number of numerical tests that confirm these results and indicate that they are not numerical artifacts. Using synthetic secular perturbation theory, we find that Mercury is destabilized via an entrance into a linear secular resonance with Jupiter in which their corresponding eigenfrequencies experience extended periods of commensurability. The effects of general relativity on the dynamical stability are discussed. An application of the bifurcation method to the outer solar system (Jupiter, Saturn, Uranus, and Neptune) showed no sign of instability during the course of 24 Gyr of integrations, in keeping with an expected Uranian dynamical lifetime of 10^(18) yr.
Quasi-sparse eigenvector diagonalization and stochastic error correction

Abstract We briefly review the diagonalization of quantum Hamiltonians using the quasi-sparse eigenvector (QSE) method. We also introduce the technique of stochastic error correction, which systematically removes the truncation error of the QSE result by stochastically sampling the contribution of the remaining basis states.
Complete Segal spaces arising from simplicial categories

In this paper, we compare several functors which take simplicial categories or model categories to complete Segal spaces, which are particularly nice simplicial spaces which, like simplicial categories, can be considered to be models for homotopy theories. We then give a characterization, up to weak equivalence, of complete Segal spaces arising from these functors.
Search algorithm for Ramsey graphs by union of group orbits

An algorithm for the construction of Ramsey graphs with a given automorphism group G is presented. To find a graph on n vertices with no clique of k vertices, Kk, and no independent set of l vertices, ¯Kl, k, l ≤ n, with an automorphism group G, a Boolean formula α based on the G-orbits of k-subsets and l-subsets of vertices is constructed from incidence matrices belonging to G. This Boolean formula is satisfiable if and only if the desired graph exists, and each satisfying assignment to α specifies a set of orbits of pairs of vertices whose union gives the edges of such a graph. Finding these assignments is basically equivalent to the conversion of α from CNF to DNF (conjunctive to disjunctive normal form). Though the latter problem is NP-hard, we present an “efficient” method to do the conversion for the formulas that appear in this particular problem. When G is taken to be the dihedral group Dn for n ≤ 101, this method matches all of the previously known cyclic Ramsey graphs, as reported by F. R. K. Chung and C. M. Grinstead [“A Survey of Bounds for Classical Ramsey Numbers,” Journal of Graph Theory, 7 (1983), 25–38], in dramatically smaller computer time when compared to the time required by an exhaustive search. Five new lower bounds for the classical Ramsey numbers are established: R(4, 7) ⩾ 47, R(4, 8) ⩾ 52, R(4, 9) ⩾ 69, R(5,7) ⩾ 76, and R(5, 8) ⩾ 94. Also, some previously known cyclic graphs are shown to be unique up to isomorphism.
Near-Infrared, Adaptive Optics Observations of the T Tauri Multiple-Star System

With high angular resolution, near-infrared observations of the young stellar object T Tauri at the end of 2002, we show that, contrary to previous reports, none of the three infrared components of T Tau seem to coincide with the compact radio source that has apparently been ejected recently from the system (Loinard, Rodriguez, & Rodriguez). The compact radio source and the infrared object it has previously been identified with, T Tau Sb, have distinct paths that departed from orbital or uniform motion between 1997 and 2000, perhaps indicating that their interaction led to the ejection of the radio source. The path that T Tau Sb took between 1997 and 2003 may indicate that this star is still bound to the presumably more massive southern component, T Tau Sa. The radio source (if indeed distinct from T Tau Sb) is absent from our near-infrared images and must therefore be fainter than K = 10.2 (if located within 100 mas of T Tau Sb, as the radio data would imply), still consistent with an identity as a low-mass star or substellar object.
Faster approximate lossy generalized flow via interior point algorithms

We present asymptotically faster approximation algorithms for the generalized flow problems in which multipliers on edges are at most 1. For this lossy version of the maximum generalized flow problem, we obtain an additive e approximation of the maximum flow in time O{m3/2 log (U/e)2}, where m is the number of edges in the graph, all capacities are integers in the range {1, ... , U}, and all loss multipliers are ratios of integers in this range. For minimum cost lossy generalized flow with costs in the range {1,... ,U}, we obtain a flow that has value within an additive e of the maximum value and cost at most the optimal cost. In many parameter ranges, these algorithms improve over the previously fastest algorithms for the generalized maximum flow problem by a factor of m1/2 and for the minimum cost generalized flow problem by a factor of approximately m1/2/ e2. The algorithms work by accelerating traditional interior point algorithms by quickly solving the system of linear equations that arises in each step. The contributions of this paper are twofold. First, we analyze the performance of interior point algorithms with approximate linear system solvers. This analysis alone provides an algorithm for the standard minimum cost flow problem that runs in time Om3/2 log U}--an improvement of roughly O{n / m1/2} over previous algorithms. Second, we examine the linear equations that arise when using an interior point algorithm to solve generalized flow problems. We observe that these belong to the family of symmetric M-matrices, and we then develop Om-time algorithms for solving linear systems in these matrices. These algorithms reduce the problem of solving a linear system in a symmetric M-matrix to that of solving O{log n} linear systems in symmetric diagonally-dominant matrices, which we can do in time Om using the algorithm of Spielman and Teng. All of our algorithms operate on numbers of bit length at most O{log n U / e}.
Risk-aware scheduling for multi-user video streaming over wireless multi-hop networks

To cope with the time-varying network conditions, various error-protection and channel adaptation strategies have been proposed at different layers of the protocol stack. However, these cross-layer strategies can be efficiently optimized only if they act on accurate information about the network conditions and hence, are able to timely adapt to network changes. We analyze the impact of such information feedback on the video quality performances of the collaborative multimedia users sharing the same multi-hop wireless infrastructure. Based on the information feedback, we can estimate the risk that packets from different priority and deadline classes will not arrive at their destination before their decoding deadline. Subsequently, cross-layer optimization strategies such as packet scheduling, retransmission (due to transmission error) limit are adapted to jointly consider the estimated risk as well as the impact in terms of distortion of not receiving different priority packets. Our results quantify the risk estimation and its benefit in different network conditions and for various video applications with different delay constraints.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Problems of atmospheric wind inputs for missile and space vehicle design

Measurement, description and presentation of wind data for missile and space vehicle design
Anomalous Diffusion of Solar Magnetic Elements

The diffusion properties of photospheric bright points associated with magnetic elements (magnetic bright points) in the granulation network are analyzed. We find that the transport is subdiffusive for times less than 20 minutes but normal for times larger than 25 minutes. The subdiffusive transport is caused by the walkers being trapped at stagnation points in the intercellular pattern. We find that the distribution of waiting times at the trap sites obeys a truncated Levy type (power-law) distribution. The fractal dimension of the pattern of sites available to the random walk is less than 2 for the subdiffusive range and tends to 2 in the normal diffusion range. We show how the continuous time random walk formalism can give an analytical explanation of the observations. We simulate this random walk by using a version of a phenomenological model of renewing cells introduced originally for supergranules by Simon, Title, & Weiss. We find that the traps that cause the subdiffusive transport arise when the renewed convection cell pattern is neither fixed nor totally uncorrelated from the old pattern, as required in Leighton's model, but in some intermediate state between these extremes.
A Dolbeault isomorphism theorem in infinite dimensions

For a large class of separable Banach spaces, we prove the real analytic Dolbeault isomorphism theorem for open subsets.
Comprehensive Analysis of Rxte Data from Cyg X-1. Spectral Index-Quasi-Periodic Oscillation Frequency-Luminosity Correlations

We present timing and spectral analysis of approx. 2.2 Ms of Rossi X-ray Time Explorer (RXTE) archival data from Cyg X-1. Using the generic Comptonization model we reveal that the spectrum of Cyg X-1 consists of three components: a thermal seed photon spectrum, a Comptonized part of the seed photon spectrum and the iron line. We find a strong correlation between 0.1-20 Hz frequencies of quasiperiodic oscillations (QPOs) and the spectral power-law index. Presence of two spectral phases (states) are clearly seen in the data when the spectral indices saturate at low and high values of QPO frequencies. This saturation effect was discovered earlier in a number of black hole candidate (BHC) sources and now we strongly confirm this phenomenon in Cyg X-1. In the soft state this index- QPO frequency correlation shows a saturation of the photon index Gamma approx. 2.1 at high values of the low frequency upsilon(sub L). The saturation level of Gamma approx. 2.1 is the lowest value found yet in BHCs. The bolometric luminosity does not show clear correlation with the index. We also show that Fe K(sub alpha) emission line strength (equivalent width, EW) correlates with the QPO frequency. EW increases from 200 eV in the low/hard state to 1.5 keV in the high/soft state. The revealed observational correlations allow us to propose a scenario for the spectral transition and iron line formation which occur in BHC sources. We also present the spectral state (the power-law index) evolution for eight years of Cyg X-1 observations by RXTE.
THE ECONOMICS OF HURRICANES AND IMPLICATIONS OF GLOBAL WARMING

This study examines the economic impacts of US hurricanes. The major conclusions are the following: First, there are substantial vulnerabilities to intense hurricanes in the Atlantic coastal United States. Damages appear to rise with the ninth power of maximum wind speed. Second, greenhouse warming is likely to lead to stronger hurricanes, but the evidence on hurricane frequency is unclear. We estimate that the average annual US hurricane damages will increase by $10 billion at 2005 incomes (0.08 percent of GDP) due to global warming. However, this number may be underestimated by current storm models. Third, 2005 appears to have been a quadruple hurricane outlier, involving a record number of North Atlantic tropical cyclones, a large fraction of intense storms, a large fraction of the intense storms making landfall in the United States, and an intense storm hitting the most vulnerable high-value region in the country.
The Interior Dynamics of Water Planets

The ever-expanding catalog of detected super-Earths calls for theoretical studies of their properties in the case of a substantial water layer. This work considers such water planets with a range of masses and water mass fractions (2-5 M Earth, 0.02%-50% H2O). First, we model the thermal and dynamical structure of the near-surface for icy and oceanic surfaces, finding separate regimes where the planet is expected to maintain a subsurface liquid ocean and where it is expected to exhibit ice tectonics. Newly discovered exoplanets may be placed into one of these regimes given estimates of surface temperature, heat flux, and gravity. Second, we construct a parameterized convection model for the underlying ice mantle of higher ice phases, finding that materials released from the silicate-iron core should traverse the ice mantle on the timescale of 0.1 to 100 megayears. We present the dependence of the overturn times of the ice mantle and the planetary radius on total mass and water mass fraction. Finally, we discuss the implications of these internal processes on atmospheric observables.
Analyst forecast accuracy: Do ability, resources, and portfolio complexity matter?

Abstract Prior studies have identified systematic and time persistent differences in analysts’ earnings forecast accuracy, but have not explained why the differences exist. Using the I/B/E/S Detail History database, this study finds that forecast accuracy is positively associated with analysts’ experience (a surrogate for analyst ability and skill) and employer size (a surrogate for resources available), and negatively associated with the number of firms and industries followed by the analyst (measures of task complexity). The results suggest that analysts’ characteristics may be useful in predicting differences in forecasting performance, and that market expectations studies may be improved by modeling these characteristics.
The Failure of Presidentialism in Central Asia

Institutional design can impact the dynamics of power relations in Central Asian states. Majoritarianism and the rigidity of the fixed terms of presidential systems are amplified by the personalist regimes of Central Asia, often leading to instability. A parliamentary system may reduce the political repression of these regimes by decreasing the stakes in each particular election. It may also increase stability due to the higher flexibility of the system. The effectiveness of the parliamentary system, however, depends largely on the existence of strong cohesive parties.
Numerical simulation of wing-fuselage interference

T wing-fuselage problem is investigated by means of the Navier-Stokes equations incorporated with an approximate turbulence model. The numerical solution yields a reasonable global agreement with experimental data in static and impact pressure distributions. However, in order to better describe the flowfield structure near the leading edge of the wing, an alternative choice of coordinate system is required.
Stochastic Estimation of Multipoint Conditional Averages and their Spatio-Temporal Evolution

Identifying coherent structures in turbulent flows has been successfully accom plished in the past using several techniques. Among them are flow visualization, proper orthogonal decomposition (POD), conditional averaging, pattern recognition, and stochastic estimation. Each of these methods has advantages, but the stochastic estimation is exceptional in its flexibility, objective nature, and ease of validation. As an illustrative problem and application of the stochastic estimation, a turbulent wake at Re d =5000 is examined at x / d=100. Single and multiple point conditionally averaged structures will be estimated and a quantitative three-dimensional flow-reconstruction technique will be used to study the flow dynamics.
Maneuver and vibration control of SCOLE

This paper is concerned with the simultaneous maneuver and vibration control of the Spacecraft Control Laboratory Experiment (SCOLE). Summaries of the derivation of the equations of motion and of a perturbation method permitting a maneuver strategy independent of the vibration control are presented. Some of the problems encountered in dynamical modeling of a flexible spacecraft in an earth-based laboratory are high-lighted and solved. Numerical results demonstrating rotational maneuvers of the SCOLE model are included.
In Situ Observation of Strains during Lithiation of a Graphite Electrode

The mechanics and microstructure of electrodes are critical in determining the performance and durability of lithium-ion batteries, especially the new large format cells and packs developed for transportation applications. During battery operation, Li diffuses into and out of the electrode particles, causing microstructural changes and deformation-induced degradation. A variety of models have been proposed to interpret these mechanical and microstructural changes, but they have no direct experimental support. We report direct in situ measurements of the microstructural strain in a composite electrode during lithium insertion using a side-by-side cell geometry. The color variation in graphite with Li concentration creates lithium spatial maps. A digital image correlation analysis provides corresponding deformation and strain fields, displaying both dilation and contraction. Through a combination of experimental measurement and theoretical analysis, the unexpected contraction during lithiation is explained by the stiffening of graphite upon lithiation. The result confirms the change in modulus that we recently predicted. Quantification of local strains shows that an increased graphite crystallite volume during lithiation is accommodated primarily by a decrease in the composite (or particle) porosity. The change in porosity can substantially impact battery power; however, this effect has generally been ignored in cell performance models for lithium-ion batteries.
An elimination reaction of N-carbomethoxy-N,N-dimethylhydrazonium salts to alkyl nitriles

Abstract A new kind of elimination of hydrazonium salts to alkyl nitriles has been developed. The reaction of hydrazones and chloroformates results in the formation of hydrazonium salts, which react in situ with water to afford alkyl nitriles. The elimination is adapted to a range of solvents and gives good yields of α-secondary and tertiary alkyl-substituted nitriles.