cssi/SciSciGPT-SciSciNet huggingface dataset:
Mask Image Planning for Deformation Control in Projection-Based Stereolithography Process

The mask-image-projection-based stereolithography process (MIP-SL) using a digital micromirror device (DMD) is an area-processing-based additive manufacturing (AM) process. In the MIP-SL process, a set of mask images are dynamically projected onto a resin surface to selectively cure liquid resin into layers of an object. Consequently, the MIP-SL process can be faster with a lower cost than the laser-based stereolithography apparatus (SLA) process. Currently an increasing number of companies are developing low-cost 3D printers based on the MIP-SL process. However, current commercially available MIP-SL systems are mostly based on Acrylate resins, which have larger shrinkages when compared to epoxy resins used in the laser-based SLA process. Consequently, controlling the shrinkage-related shape deformation in the MIP-SL process is challenging. In this research, we evaluate different mask image exposing strategies for building part layers and their effects on the deformation control in the MIP-SL process. Accordingly, a mask image planning method and related algorithms have been developed for a given computer-aided design (CAD) model. The planned mask images have been tested by using a commercial MIP-SL machine. The experimental results illustrate that our method can effectively reduce the deformation by as much as 32%. A discussion on the advantages and disadvantages of the mask image planning method and future research directions are also presented.
An evolutionary game theory explanation of ARCH effects

Abstract While ARCH/GARCH equations have been widely used to model financial market data, formal explanations for the sources of conditional volatility are scarce. This paper presents a model with the property that standard econometric tests detect ARCH/GARCH effects similar to those found in asset returns. We use evolutionary game theory to describe how agents endogenously switch among different forecasting strategies. The agents evaluate past forecast errors in the context of an optimizing model of asset pricing given heterogeneous agents. We show that the prospects for divergent expectations depend on the relative variances of fundamental and extraneous variables and on how aggressively agents are pursuing the optimal forecast. Divergent expectations are the driving force leading to the appearance of ARCH/GARCH in the data.
Physics basis and simulation of burning plasma physics for the fusion ignition research experiment (FIRE)

The FIRE design for a burning plasma experiment is described in terms of its physics basis and engineering features. Systems analysis indicates that the device has a wide operating space to accomplish its mission, both for the ELMy H-mode reference and the high bootstrap current/high-β advanced tokamak regimes. Simulations with 1.5D transport codes reported here both confirm and constrain the systems projections. Experimental and theoretical results are used to establish the basis for successful burning plasma experiments in FIRE.
Molecular dynamics simulation of thermal conductivity of nanocrystalline composite films

The efficiency of a thermoelectric material is measured by the figure of merit ZT, which is inversely proportional to the thermal conductivity. Superlattice structures often have a reduced thermal conductivity because of the introduction of interface scattering and, therefore, improved performance. The present work is focused on the effective thermal conductivity of nanocomposite films. This configuration could also improve ZT because of phonon-interface scattering introduced by the nanocrystals. The effects of crystal size and mass fraction are studied numerically using a molecular dynamics simulation. Results indicate that a reduction of 25% in the effective thermal conductivity can be achieved with the addition of nanocrystals which is comparable to that found in experimental measurement. However, the effective thermal conductivity was never reduced below the alloy limit.
COLORING INVARIANTS OF SPATIAL GRAPHS

We define the fundamental quandle of a spatial graph and several invariants derived from it. In the category of graph tangles, we define an invariant based on the walks in the graph and cocycles from nonabelian quandle cohomology.
The Redshift of GRB 970508

GRB 970508 is the second gamma-ray burst (GRB) for which an optical afterglow has been detected. It is the first GRB for which a distance scale has been determined: absorption and emission features in spectra of the optical afterglow place GRB 970508 at a redshift of z ≥ 0.835. The lack of a Lyα forest in these spectra further constrains this redshift to be less than z~2.3. I show that the spectrum of the optical afterglow of GRB 970508, once corrected for Galactic absorption, is inconsistent with the relativistic blast-wave model unless a second, redshifted source of extinction is introduced. This second source of extinction may be the yet unobserved host galaxy. I determine its redshift to be z = 1.09+0.14−0.41, which is consistent with the observed redshift of z = 0.835. Redshifts greater than z = 1.40 are ruled out at the 3 σ confidence level.
Inorganic Semiconductor Nanowires: Rational Growth, Assembly, and Novel Properties

Rationally controlled growth of inorganic semiconductor nanowires is important for their applica- tions in nanoscale electronics and photonics. In this article, we discuss the rational growth, physical proper- ties, and integration of nanowires based on the results from the authors× laboratory. The composition, diameter, growth position, and orientation of the nanowires are controlled based on the vapor ± solid ± liquid (VLS) crystal growth mechanism. The thermal stability and optical properties of these semiconductor nanowires are investigated. Particularly, ZnO nanowires with well- defined end surfaces can function as room-temperature ultraviolet nanolasers. In addition, a novel microfluidic- assisted nanowire integration (MANI) process was de- veloped for the hierarchical assembly of nanowire build- ing blocks into functional devices and systems.
Status of Lattice Flavor Physics

This talk reviews recent lattice QCD calculations relevant for quark flavor physics. Since lattice results must be accurate and precise to play a definitive role in phenomenology, the focus is on unquenched results of quantities which can be calculated most reliably.
D-bar Operators on Quantum Domains

We study the index problem for the d-bar operators subject to Atiyah- Patodi-Singer boundary conditions on noncommutative disk and annulus.
On rapid idempotent ultrafilters

This short note contains the proofs of two small but somewhat surprising results about ultrafilters on \(\mathbb {N}\): (1) strongly summable ultrafilters are rapid, (2) every rapid ultrafilter induces a closed left ideal of rapid ultrafilters. As a consequence, there will be rapid minimal idempotents in all models of set theory with rapid ultrafilters. The history of this result has been published as an experiment in mathematical writing on the author’s website (Krautzberger, One Day in Colorado or Strongly Summable Ultrafilters are Rapid, 2012) and (Krautzberger, Rapid Idempotent Ultrafilters, 2012) where you can can also find additional remarks by Blass and Hindman, offering a form of peer-review.
A DEEP CHANDRA X-RAY SPECTRUM OF THE ACCRETING YOUNG STAR TW HYDRAE

We present X-ray spectral analysis of the accreting young star TW Hydrae from a 489 ks observation using the Chandra High Energy Transmission Grating. The spectrum provides a rich set of diagnostics for electron temperature T{sub e} , electron density N{sub e} , hydrogen column density N{sub H} , relative elemental abundances, and velocities, and reveals its source in three distinct regions of the stellar atmosphere: the stellar corona, the accretion shock, and a very large extended volume of warm postshock plasma. The presence of Mg XII, Si XIII, and Si XIV emission lines in the spectrum requires coronal structures at {approx}10 MK. Lower temperature lines (e.g., from O VIII, Ne IX, and Mg XI) formed at 2.5 MK appear more consistent with emission from an accretion shock. He-like Ne IX line ratio diagnostics indicate that T{sub e} = 2.50 +- 0.25 MK and N{sub e} = 3.0 +- 0.2 x 10{sup 12} cm{sup -3} in the shock. These values agree well with standard magnetic accretion models. However, the Chandra observations significantly diverge from current model predictions for the postshock plasma. This gas is expected to cool radiatively, producing O VII as it flows into an increasingly dense stellar atmosphere.more » Surprisingly, O VII indicates N{sub e} = 5.7{sup +4.4}{sub -1.2} x 10{sup 11} cm{sup -3}, 5 times lower than N{sub e} in the accretion shock itself and {approx}7 times lower than the model prediction. We estimate that the postshock region producing O VII has roughly 300 times larger volume and 30 times more emitting mass than the shock itself. Apparently, the shocked plasma heats the surrounding stellar atmosphere to soft X-ray emitting temperatures and supplies this material to nearby large magnetic structures-which may be closed magnetic loops or open magnetic field leading to mass outflow. Our model explains the soft X-ray excess found in many accreting systems as well as the failure to observe high N{sub e} signatures in some stars. Such accretion-fed coronae may be ubiquitous in the atmospheres of accreting young stars.« less
Vaccinating Sons against HPV: Results from a U.S. National Survey of Parents

Purpose The quadrivalent HPV vaccination was approved for use in males ages 9 to 26 in 2009 and recommended for routine administration in 2011. The purpose of this study was to uncover predictable commonalities amongst parents who chose to vaccinate their 11–17 year old sons against HPV. Methods We compiled data from a U.S. national sample of 779 parents with sons 11–17 years old using a web-based survey to gather information about behavioral and sociodemographic factors which predicted receipt of 1 or more HPV vaccine doses based on parental report. Predictors were first modeled individually for univariable associations. Significant predictors (p<0.10) were combined in a multivariable model. Results In the adjusted model, independent predictors included receipt of flu vaccination, health insurance coverage and sexual health topic discussions with sons. Sons who had received a flu shot in the last two years more frequently received at least one dose of the vaccine (OR 1.82; 95% CI 1.45–2.26). Sons covered by private health insurance had decreased odds of HPV vaccination (OR 0.56 95% CI 0.37–0.83). Lastly, parents who had discussed sexual health topics with their sons were more likely to vaccinate (OR 1.61; 95% CI 1.37–1.89). Conclusions Male vaccination rates in the U.S. have increased, but males continue to be under-immunized. Utilization of health care is an important factor in HPV vaccine uptake; therefore, health care providers should use every contact as an opportunity to vaccinate. Communication about sexual health topics may provide a forum for parents and health care providers to have conversations about HPV vaccination as those more comfortable discussing these topics may also be more comfortable discussing HPV vaccination.
Prediction of Delamination Growth and Opening Near Intersection of Transverse Matrix Cracks and Delamination

The use of advanced composite materials for cryogenic fuel tanks reduces the mass of the structure but microscopic damage can cause fuel leakage. The amount of leakage depends on the connectivity of the damage and crack opening displacements. In this paper, the damage growth and the opening near the intersection of transverse matrix cracks (TMC) and a delamination are discussed. Three-dimensional finite element analysis (FEA) was used to analyze cross-ply and angle-ply graphite/epoxy laminates. The strain energy release rates (SERR) along the delamination front were calculated based on the virtual crack closure technique. The strain energy release rate has a very large variation along the delamination front and is sensitive to a variety of geometric and load parameters. There is an extreme gradient of the strain energy release rate near the intersection of the delamination front and the TMC. Based on the SERR results, likely delamination shape and size for cross- and angle-ply laminates were determined. P...
Rh(I)-catalyzed alkylation of quinolines and pyridines via C-H bond activation.

The scope of heterocycle ortho-alkylation has been dramatically expanded to include pharmaceutically important pyridines and quinolines, which contain only a single nitrogen. The reactions, which are conducted at a high concentration (0.8 M), can be performed with catalyst loadings as low as 1% Rh. Substitution ortho to the heterocycle ring nitrogen is required for efficient alkylation and is consistent with the intermediacy of a Rh−carbene intermediate similar to those proposed in our earlier work.
Decarboxylative benzylations of alkynes and ketones.

Benzyl esters of propiolic and β-keto acids undergo catalytic decarboxylative coupling when treated with appropriate palladium catalysts. Such decarboxylative couplings allow the benzylation of alkynes without the use of strong bases and/or organometallics. This allows the synthesis of sensitive benzylic alkynes that are prone to undergo isomerizations under basic conditions. Additionally, decarboxylation facilitates the site-specific benzylation of diketones and ketoesters under mild, base-free conditions. Ultimately, the methodology described expands our ability to cross-couple medicinally relevant heterocycles.
Local-Global Analysis of Crack Growth in Continuously Reinforced Ceramic Matrix Composites

This paper describes the development of a mathematical model for predicting the strength and micromechanical failure characteristics of continuously reinforced ceramic matrix composites. The local-global analysis models the vicinity of a propagating crack tip as a local heterogeneous region (LHR) consisting of springlike representations of the matrix, fibers, and interfaces. This region is embedded in an anisotropic continuum (representing the bulk composite), which is modeled by conventional finite elements. Parametric studies are conducted to investigate the effects of LHR size, component properties, interface conditions, etc. on the strength and sequence of the failure processes in the unidirectional composite system. The results are compared with those predicted by the models developed by Marshall et al. (1985) and by Budiansky et al. (1986).
A lower bound for the canonical height on elliptic curves over abelian extensions

Abstract Let E/K be an elliptic curve defined over a number field, let ĥ be the canonical height on E, and let Kab/K be the maximal abelian extension of K. Extending work of M. Baker (IMRN 29 (2003) 1571–1582), we prove that there is a constant C(E/K)>0 so that every nontorsion point P∈E(Kab) satisfies h (P)>C(E/K) .
Surface extrapolation length and director structures in confined nematics

We report the results of Monte Carlo simulations of the Lebwohl-Lasher model of nematic liquid crystals confined to cylindrical cavities with homeotropic anchoring. We show that the ratio of the bulk to surface couplings is not in general equal to the corresponding parameter $K/W$ used in elastic theory (where K is the Frank elastic constant in the one-constant approximation and W is the surface anchoring strength). By measuring the temperature dependence of $K/W$ (which is equivalent to the surface extrapolation length) we are able to reconcile the results of our simulations as well as others with the predictions of elastic theory. We find that the rate at which we cool the system from the isotropic to nematic phase plays a crucial role in the development of the final director structure, because of a large free energy barrier separating different director structures as well as the temperature dependence of $K/W.$ With a suitably fast cooling rate we are able to keep the system out of a metastable planar state and form an escaped radial structure for large enough systems. \textcopyright{}2000 The American Physical Society.
Self-coincidence numbers and the fundamental group

For M and N closed oriented connected smooth manifolds of the same dimension, we consider the mapping space Map(M,N; f) of continuous maps homotopic to \(f : M \longrightarrow N\) . We will show that the evaluation map from the space of maps to the manifold N induces a nontrivial homomorphism on the fundamental group only if the self-coincidence number of f, denoted \(\Lambda_{f,f}\) , equals zero. Since \(\Lambda_{f,f}\) is equal to the product of the degree of f and the Euler characteristic of N, we obtain results related to earlier results about the evaluation map and the Euler characteristic.
Tropical intersection theory from toric varieties

We apply ideas from intersection theory on toric varieties to tropical intersection theory. We introduce mixed Minkowski weights on toric varieties which interpolate between equivariant and ordinary Chow cohomology classes on compact toric varieties. These objects fit into the framework of tropical intersection theory developed by Allermann and Rau. Standard facts about intersection theory on toric varieties are applied to show that the definitions of tropical intersection product on tropical cycles in $${\mathbb{R}^n}$$ given by Allermann–Rau and Mikhalkin are equivalent. We introduce an induced tropical intersection theory on subvarieties on a toric variety. This gives a conceptual proof that the intersection of tropical ψ-classes on $${\overline{\mathcal{M}}_{0,n}}$$ used by Kerber and Markwig computes classical intersection numbers.
Linear Scaling Solution of the Time-Dependent Self-Consistent-Field Equations

A new approach to solving the Time-Dependent Self-Consistent-Field equations is developed based on the double quotient formulation of Tsiper 2001 (J. Phys. B). Dual channel, quasi-independent non-linear optimization of these quotients is found to yield convergence rates approaching those of the best case (single channel) Tamm-Dancoff approximation. This formulation is variational with respect to matrix truncation, admitting linear scaling solution of the matrix-eigenvalue problem, which is demonstrated for bulk excitons in the polyphenylene vinylene oligomer and the (4,3) carbon nanotube segment.
Messages for QCD from the Superworld

Recent discoveries in supersymmetric gauge theories have significant implications for our understanding for QCD and of field theory in general. The phases of N = 1 supersymmetric QCD (SQCD) are discussed, and the possibility of similar phases in non-supersymmetric QCD is emphasized. It is described how duality in SQCD links many previously known duality transformations that were thought to be distinct, including Olive-Montonen duality of N = 4 supersymmetric gauge theory and quarkhadron duality in (S)QCD. A link between Olive-Montonen duality and the confining strings of (S)QCD is explained, in which a picture of confinement via non-abelian monopole condensation — a generalized dual Meissner effect — emerges explicitly. In this picture, unlike previous ones, the confining flux tubes carry the correct ZN discrete charges. A number of studies of these subjects, which could be carried out using lattice gauge theory, are proposed. ∗) Talk given at YKIS’97, Kyoto, Japan. ∗∗) E-mail address: strassler@ias.edu 1 typeset using PTPTEX.sty
A new polyketide, secocurvularin, from the salt water culture of a sponge derived fungus

Abstract The salt water culture of an unidentified fungus separated from the Indo-Pacific sponge Spirastrella vagabunda has yielded a new mildly antibiotic polyketide, 14,15-secocurvularin ( 1 ).
Closed-Cycle Gas Turbine Working Fluids

Characteristic requirements of a closed-cycle gas turbine (CCGT) working fluid were identified and the effects of their thermodynamic and transport properties on the CCGT cycle performance, required heat exchanger surface area and metal operating temperature, cycle operating pressure levels, and the turbomachinery design were investigated. Material compatibility, thermal and chemical stability, safety, cost, and availability of the working fluid were also considered in the study. This paper also discusses CCGT working fluids utilizing mixtures of two or more pure gases. Some mixtures of gases exhibit pronounced synergetic effects on their characteristic properties including viscosity, thermal conductivity and Prandtl number, resulting in desirable heat transfer properties and high molecular weights. Typical examples of such synergetic gas mixture are helium-xenon and helium-carbon dioxide.
BACKLASH COMPENSATION IN NONLINEAR SYSTEMS USING DYNAMIC INVERSION BY NEURAL NETWORKS

A dynamic inversion compensation scheme is presented for backlash. The compensator uses the backstepping technique with neural networks (NN) for inverting the backlash nonlinearity in the feedforward path. The technique provides a general procedure for using NN to determine the dynamic preinverse of an invertible dynamical system. A tuning algorithm is presented for the NN backlash compensator which yields a stable closed-loop system.
A Polarization Survey of SiO Maser Variability in Evolved Stars

We have monitored the SiO (v = 1, J = 2 → 1) maser polarization in 17 variable stars (Miras, OH-IR stars, and supergiants) to investigate the long-term persistence of masers. The eight epochs of observations span 2.5 yr, thereby sampling multiple cycles for these stars with typical periods of ~1 yr. The average polarization was 23% with a typical dispersion of 7%, although the variability differed substantially from star to star. In the Stokes q and u spectra of individual stars, a few strong maser features tended to dominate the polarization, with the maser features persisting for less than one stellar cycle for some stars, and for multiple cycles for a few stars. Because individual masers are not resolved in our beam-averaged total intensity spectra, we correlated the polarization spectra between epochs to measure the characteristic lifetimes of the features, rather than attempting to trace the evolution of separate line components. We found that individual maser feature lifetimes ranged from a few months or less to more than 2 yr. These data indicate that for the sample of stars as a whole, the masers are not reset at a particular stellar phase.
A Simple Theory of the Financial Crisis; or, Why Fischer Black Still Matters

The key question about the current financial crisis is how so many investors could have mispriced risk in the same way and at the same time. This article looks at the work of Fischer Black for insight into this problem. In particular, Black considered why the “law of large numbers” does not always apply to expectations in a market setting. Black’s hypothesis that a financial crisis can arise from extreme bad luck is more plausible than is usually realized. In this view, such factors as the real estate market are of secondary importance for understanding the economic crisis, and the financial side of the crisis may have roots in the real economy as a whole.
Hitting the Bull's-Eye: The Radial Profile of Accretion and Star Formation in the Milky Way

Ongoing star formation in the Milky Way requires continuous gaseous fuel from accretion. Previous work has suggested that the accretion of dwarf galaxies could provide the needed gas for this process. In this work, we investigate whether dwarf galaxy accretion is consistent with the radial profile of star formation observed in the Milky Way, which is strongly concentrated toward the center of the gaseous disk of the Galaxy. Using realistic parameters for the Galactic potential, gaseous halo, Galactic disk, velocities of dwarf galaxies, and effects of drag on stripped gas in the halo, we model the distribution of radii at which dwarf galaxies accrete onto the Galactic disk. We also model the radial distribution of the accretion of gas that cools directly out of the halo by examining the results of recent simulations. We show that dwarf galaxies cannot reproduce the concentration of accretion toward the center of the Galaxy required by star formation. We also show that clouds that cool directly from the halo can reproduce this central concentration, and conclude that this difference is largely due to the discrepancy in absolute specific angular momentum between the two mechanisms.
A simple and efficient preconditioning scheme for heaviside enriched XFEM

The extended finite element method (XFEM) is an approach for solving problems with non-smooth solutions, which arise from geometric features such as cracks, holes, and material inclusions. In the XFEM, the approximate solution is locally enriched to capture the discontinuities without requiring a mesh which conforms to the geometric features. One drawback of the XFEM is that an ill-conditioned system of equations results when the ratio of volumes on either side of the interface in an element is small. Such interface configurations are often unavoidable, in particular for moving interface problems on fixed meshes. In general, the ill-conditioning reduces the performance of iterative linear solvers and impedes the convergence of solvers for nonlinear problems. This paper studies the XFEM with a Heaviside enrichment strategy for solving problems with stationary and moving material interfaces. A generalized formulation of the XFEM is combined with the level set method to implicitly define the embedded interface geometry. In order to avoid the ill-conditioning, a simple and efficient scheme based on a geometric preconditioner and constraining degrees of freedom to zero for small intersections is proposed. The geometric preconditioner is computed from the nodal basis functions, and therefore may be constructed prior to building the system of equations. This feature and the low-cost of constructing the preconditioning matrix makes it well suited for nonlinear problems with fixed and moving interfaces. It is shown by numerical examples that the proposed preconditioning scheme performs well for discontinuous problems and $$C^0$$C0-continuous problems with both the stabilized Lagrange and Nitsche methods for enforcing the continuity constraint at the interface. Numerical examples are presented which compare the condition number and solution error with and without the proposed preconditioning scheme. The results suggest that the proposed preconditioning scheme leads to condition numbers similar to that of a body-fitted mesh using the traditional finite element method without loss of solution accuracy.
A novel anionic condensation, fragmentation, and elimination reaction of bicyclo[2.2.1]heptenone ring systems.

We have identified an unprecedented anionic condensation, fragmentation, and elimination sequence from the coupling of bicyclo[2.2.1]heptenones with aldehydes. This reaction leads to the stereoselective formation of disubstituted five-membered rings which are present in a wide array of bioactive molecules.
Language acquisition and language change

Children acquire a mature language system and sometimes this system differs from that of their parents. This is a significant part of language change and understanding acquisition is key to understanding this kind of change in people's internal grammars. I outline one approach to language acquisition, based on children finding cues expressed in the input they are exposed to. This enables us to understand historical change in grammars: change in external language sometimes triggers a new internal grammar as cues come to be expressed differently. Work on language variation, acquisition, and change converges, and these three areas are mutually dependent; empirical work in one area may enrich understanding more generally, opening the way to new kinds of empirical work. Seen this way, language is a complex system and language change can be treated productively in the context of complexity science. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.
RADIO CONTINUUM EVIDENCE FOR OUTFLOW AND ABSORPTION IN THE SEYFERT 1 GALAXY MARKARIAN 231

The Very Long Baseline Array (VLBA) and the Very Large Array (VLA) have been used to image the continuum radio emission from Mrk 231, a Seyfert 1 galaxy and the brightest infrared galaxy in the local universe. The smallest VLBA scales reveal a double, or possibly triple, source less than 2 pc in extent. The components of this central source have minimum brightness temperatures of 109-1010 K and spectral turnovers between 2 and 10 GHz and appear to define the galaxy nucleus plus the inner regions of a jet. The strongest component is probably synchrotron self-absorbed, while the weaker component to the northeast may be either free-free absorbed or synchrotron self-absorbed. On larger VLBA scales, the images confirm a previously known north-south triple source extending 40 pc and elongated perpendicular to a 350 pc starburst disk traced by H I and CO. Both lobes of the triple show evidence for free-free absorption near 2 GHz, probably due to ionized gas with a density of (1-2) × 103 cm-3 in the innermost regions of the starburst disk. This free-free absorption resembles that toward the counterjet of 3C 84 but requires ionized gas at lower density located considerably farther from the central source. The absorbing gas may be ionized by the active nucleus or by local regions of enhanced star formation, possibly in the inner part of the starburst disk. The elongation position angle of the 40 pc triple differs by 65° from that of the 2 pc source. Unless the radio source is seen nearly end-on, the different symmetry axes on different scales in Mrk 231 imply a dramatic curvature in the inner part of the Mrk 231 radio jet. A comparison of VLBA and VLA flux densities indicates that the radio continuum from the 350 pc disk has a spectral index near -0.4 at frequencies above 1.4 GHz and is plausibly energized by a massive burst of star formation, with the overall spectrum flattened somewhat by a contribution from free-free absorption. On VLA scales, asymmetric and diffuse emission extends for more than 25 kpc. This emission has a steep spectrum, exhibits linear polarization exceeding 50% at some locations, and shares the symmetry axis of the 40 pc triple, but on a scale larger by 3 orders of magnitude. The large-scale radio emission extends beyond the bulk of the optical galaxy but has an initial axis similar to a series of optical star-forming knots several kiloparsecs from the nucleus. This diffuse radio source is probably generated by energy deposition from a slow-moving nuclear jet, which conceivably could help energize the off-nuclear starburst as well.
Peptide ligands for pro-survival protein Bfl-1 from computationally guided library screening.

Pro-survival members of the Bcl-2 protein family inhibit cell death by binding short helical BH3 motifs in pro-apoptotic proteins. Mammalian pro-survival proteins Bcl-xL, Bcl-2, Bcl-w, Mcl-1 and Bfl-1 bind with varying affinities and specificities to native BH3 motifs, engineered peptides and small molecules. Biophysical studies have determined interaction patterns for these proteins, particularly for the most-studied family members Bcl-xL and Mcl-1. Bfl-1 is a pro-survival protein implicated in preventing apoptosis in leukemia, lymphoma and melanoma. Although Bfl-1 is a promising therapeutic target, relatively little is known about its binding preferences. We explored the binding of Bfl-1 to BH3-like peptides by screening a peptide library that was designed to sample a high degree of relevant sequence diversity. Screening using yeast-surface display led to several novel high-affinity Bfl-1 binders and to thousands of putative binders identified through deep sequencing. Further screening for specificity led to identification of a peptide that bound to Bfl-1 with Kd < 1 nM and very slow dissociation from Bfl-1 compared to other pro-survival Bcl-2 family members. A point mutation in this sequence gave a peptide with ~50 nM affinity for Bfl-1 that was selective for Bfl-1 in equilibrium binding assays. Analysis of engineered Bfl-1 binders deepens our understanding of how the binding profiles of pro-survival proteins differ, and may guide the development of targeted Bfl-1 inhibitors.
Solvent-initiated photochemistry of transition metal complexes

Abstract Although it is generally assumed that photoreactions of transition metal complexes proceed through metal complex excited states, some reactions in halogenated solvents occur instead as radical processes, following carbon-halogen bond homolysis. Oxidation, substitution, or oxidative addition can occur by either a metal-centered or a solvent-initiated photoreaction, and they can be hard to distinguish. Under some circumstances even the kinetic rate laws can be the same. However, with proper choice of irradiation wavelength the dependence of the initial rate on light intensity and metal complex concentration suffices to discriminate between the two possibilities.
Acetoxylation of 6,7-dialkoxy-substituted 1,4-dihydroquinoxaline-2,3-diones (Qxs) using fuming nitric acid in acetic acid: A facile synthesis of 5-acyloxy-6,7-dialkoxy QXs

Abstract Treatment of 6,7-dialkoxy-1.4-dihydroquinoxaline-2.3-diones 3 with fuming nitric acid in acetic acid at 25 °C resulted in an acetoxylation reaction, giving 5-acetoxy-6,7-dialkoxy-1,4-dihydroquinoxaline-2 .3-diones 4 in moderate yields A mechanism involving ipso attack of nitronium ion as the first step is proposed.
K8In10Hg : a Zintl phase with isolated In10Hg clusters

Abstract The title compound results from the substitution of one mercury atom for indium in the known metallic K 8 In 11 [8K + + In 11 7− + e − ]. It contains the same isolated eleven-atom clusters as before, pentacapped trigonal prisms compressed along the three-fold axis, but with mercury disordered over the trigonal prismatic sites ( P6 3 /m, Z = 2, a = 9.9812(4) A , c = 16.851(1) A , R/R w = 2.4/2.8% ). The cluster In 10 Hg 8− is likewise hypoelectronic and requires the 2 n − 4 = 18 skeletal bonding electrons available for this stoichiometry. The close-packed layers of clusters are again separated by double layers of potassium, but these follow an h.c.p. order rather than the c.c.p. arrangement found in K 8 In 11 . The phase is diamagnetic (∼ −3.5 × 10 −4 emu mol −1 ), in contrast to the Pauli-like behavior of K 8 In 11 , but it too exhibits a conductivity characteristic of a poor metal or a semimetal, ρ 295 ∼ 270 μΩ −1 cm −1 with a coefficient of +0.48% deg −1 .
Quantum cellular neural networks

Abstract We have previously proposed a way of using coupled quantum dots to construct digital computing elements—quantum-dot cellular automata. Here we consider a different approach to using coupled quantum-dot cells in an architecture which, rather than reproducing Boolean logic, uses a physical near-neighbor connectivity to construct an analog cellular neural network.
Superacid-catalyzed preparation of aryl-substituted piperidines via dicationic electrophiles

Abstract The electrophilic chemistry of 1,2,3,6-tetrahydropyridines has been studied in the Bronsted superacid, CF3SO3H (triflic acid). The 1,2,3,6-tetrahydropyridines react with arenes to give aryl-substituted piperidines. It is proposed that the reactions occur through dicationic electrophilic intermediates. Depending upon substituents, either 1,4-dications or 1,3-dications are formed. The dicationic intermediates react with moderately deactivated arenes, such as o-dichlorobenzene.
P-I-N CdTe Gamma Ray Detectors by Liquid Phase Epitaxy (LPE)

A new device concept for CdTe gamma ray detectors has been demonstrated using p+(HgCdTe)-n(CdTe)-n+ (HgCdTe) diode structures. Both P+ and n+ Hg0.25Cd0.75Te epilayers were grown by the liquid phase epitaxy (LPE) technique on semi-insulating CdTe sensor elements. The LPE grown P-I-N structure offers potential advantages for p-n junction and ohmic contact formation over standard ion implanted diodes or Schottky barrier devices. Detectors with active areas of 2 mm2 were fabricated. Resolutions of 10 KeV were obtained for the 122 KeV gamma peak of Co57 at room temperature.
Information acquisition and optimal project management

Abstract This paper provides a rationale for why an organization often generates a bias in favor of a new project even after learning that its profitability will be certainly below more conventional ones. We analyze a principal–agent model with two alternative projects, one of which is to be chosen by the principal. In our model, the profitability of a project is determined by the cost of implementation. All parties are familiar with one of the projects (the known project), and thus the implementation cost of this project is common knowledge. Information on the other project (the new project), however, must be acquired by the agent. We find that the new project may be chosen in the optimal contract even when it turns out to be more costly to implement than the known project, if acquiring information is costly enough and the realized implementation cost of the new project is below a particular level. We also discuss distortion in the new project's output schedule when it is selected.
THE STRUCTURE OF MAGNETOCENTRIFUGAL WINDS. I. STEADY MASS LOADING

We present the results of a series of time-dependent numerical simulations of cold, magnetocentrifugally launched winds from accretion disks. The goal of this study is to determine how the mass loading from the disk affects the structure and dynamics of the wind for a given distribution of magnetic fields. Our simulations span 4.5 dex of mass loading; in the context of a disk with a launching region from 0.1 to 1.0 AU around a 1 M☉ star and a field strength of about 20 G at the inner disk edge, this amounts to mass-loss rates of 1 × 10-9-3 × 10-5 M☉ yr-1 from each side of the disk. We find that, as expected intuitively, the degree of collimation of the wind increases with mass loading; however, even the "lightest" wind simulated is significantly collimated compared with the force-free magnetic configuration of the same magnetic flux distribution at the launching surface, which becomes radial at large distances. The implication is that for flows from young stellar objects, a radial field approximation is inappropriate. Surprisingly, the terminal velocity of the wind and the magnetic lever arm are still well described by the analytical solutions for a radial field geometry. We also find that the isodensity contours and the Alfven surface are approximately self-similar in mass loading. The wind becomes unsteady above some critical mass-loading rate. The exact value of the critical rate depends on the (small) velocity with which we inject the material into the wind. For a small enough injection speed, we are able to obtain the first examples of a class of heavily loaded magnetocentrifugal winds with magnetic fields completely dominated by the toroidal component all the way to the launching surface. The stability of such toroidally dominated winds in three dimensions will be the subject of a future investigation.
Migration of cytotoxic lymphocytes in cell cycle permits local MHC I–dependent control of division at sites of viral infection

After virus infection, cytotoxic T lymphocytes (CTLs) divide rapidly to eradicate the pathogen and prevent the establishment of persistence. The magnitude of an antiviral CTL response is thought to be controlled by the initiation of a cell cycle program within lymphoid tissues. However, it is presently not known whether this division program proceeds during migration or is influenced locally at sites of viral infection. We demonstrate that antiviral CTLs remain in cell cycle while transiting to infected tissues. Up to one third of virus-specific CTLs within blood were found to be in cell cycle after infection with lymphocytic choriomeningitis virus or vesicular stomatitis virus. Using two-photon microscopy, we found that effector CTL divided rapidly upon arrest in the virus-infected central nervous system as well as in meningeal blood vessels. We also observed that MHC I–dependent interactions, but not costimulation, influenced the division program by advancing effector CTL through stages of the cell cycle. These results demonstrate that CTLs are poised to divide in transit and that their numbers can be influenced locally at the site of infection through interactions with cells displaying cognate antigen.
Fads, Martingales, and Market Efficiency

Predictable variation in equity returns might reflect either (1) predictable changes in expected returns or (2) market inefficiency and stock price "overreaction." These explanations can be distinguished by examining returns over short time intervals since systematic changes in fundamental valuation over intervals like a week should not occur in efficient markets. The evidence suggests that the "winners" and "losers" one week experience sizeable return reversals the next week in a way that reflects apparent arbitrage profits which persist after corrections for bid-ask spreads and plausible transactions costs. This probably reflects inefficiency in the market for liquidity around large price changes.
Citric acid-sonication method for the isolation of nucleoli.

Abstract A simple method has been developed for the isolation of nucleoli of Novikoff hepatoma ascites cells from nuclei prepared by the citric acid procedure. The purity of the nucleoli is equivalent to that of nucleoli isolated by the sucrose-Ca 2+ method [3, 16]. Chemical compositions and RNA profiles were virtually identical to those reported earlier [3, 10, 16]. In addition, the nucleoli isolated by this method had no ribonuclease activity. The average yield of 64% is higher than that of the method employing sucrose and Ca 2+ . This method has been successful both for cells obtained directly from ascites fluid and for cells incubated in minimal Eagle's medium for 16 h. For the latter condition, the sucrose-Ca 2+ method did not yield satisfactory results [13].
Using directionality in mobile routing

The increased usage of directional methods of communications has prompted research into leveraging directionality in every layer of the network stack. In this paper, we explore the use of directionality in layer 3 to facilitate routing in highly mobile environments. We introduce Mobile Orthogonal Rendezvous Routing Protocol (MORRP) for mobile ad-hoc networks (MANETs). MORRP is a lightweight, but scalable routing protocol utilizing directional communications (such as directional antennas or free-space-optical transceivers) to relax information requirements such as coordinate space embedding, node localization, and mobility. This relaxation is done by introducing a novel concept called the directional routing table (DRT) which maps a set-of-IDs to each interface direction to provide probabilistic routing information based on interface direction. We show that MORRP achieves connectivity with high probability even in highly mobile environments while maintaining only probabilistic information about destinations. Additionally, we compare MORRP with various proactive, reactive, and position-based routing protocols using single omni-directional interfaces and multiple directional interfaces and show that MORRP gains over 10---14 × additional goodput vs. traditional protocols and 15---20% additional goodput vs. traditional protocols using multiple interfaces. MORRP scales well without imposing DHT-like graph structures (eg: trees, rings, torus etc). We also show that high connectivity can be achieved without the need to frequently disseminate node position resulting increased scalability even in highly mobile environments.
HYPOTHESIS GENERATION IN CONFLICT-BASED DIAGNOSIS

The goal of diagnostic reasoning is to identify malfunction (disease) that best accounts for the observed discrepancies (symptoms) in system behavior. Model-based diagnosis emerges as an alternative to both the empirical symptom-based and traditional fault-model-based approaches. Within the model-based paradigm, there is an important approach which bases its reasoning on conflicts for diagnosing multiple failures. We refer to such an approach as conflict-based diagnosis in this work. Previous conflict-based diagnostic systems resort to some objective notion of parsimony, e.g. nonredundancy, to reduce the exponential search space of hypotheses. Instead of using subjective measures, a probabilistic model is developed which provides an objective measure for ranking hypotheses. Based on the probabilistic model, an algorithm which generates plausible diagnostic hypotheses in decreasing order of their probabilities is presented. Some possible uses of the algorithm are discussed.
Nucleic acid extraction techniques and application to the microchip

As recently as the early 1990s, DNA purification was time-consuming, requiring the use of toxic, hazardous reagents. The advent of solid phase extraction techniques and the availability of commercial kits for quick and reliable DNA extraction has relegated those early techniques largely to the history books. High quality DNA can now be extracted from whole blood, serum, saliva, urine, stool, cerebral spinal fluid, tissues, and cells in less time without sacrificing recovery. Having achieved such a radical change in the methodology of DNA extraction, focus has shifted to adapting these methods to a miniaturized system, or “lab-on-a-chip” (A. Manz, N. Graber and H. M. Widmer, Sens. Actuators, B, 1990, 1, 244–248).1 Manz et al.'s concept of a “miniaturized total chemical analysis system” (µTAS) involved a silicon chip that incorporated sample pretreatment, separation and detection.1 This review will focus on the first of these steps, sample pretreatment in the form of DNA purification. The intention of this review is to provide an overview of the fundamentals of nucleic acid purification and solid phase extraction (SPE) and to discuss specific microchip DNA extraction successes and challenges. In order to fully appreciate the advances in DNA purification, a brief review of the history of DNA extraction is provided so that the reader has an understanding of the impact that the development of SPE techniques have had. This review will highlight the different methods of nucleic acid extraction (Table 1), including relevant citations, but without an exhaustive summary of the literature. A recent review by Wen et al. (J. Wen, L. A. Legendre, J. M. Bienvenue and J. P. Landers, Anal. Chem., 2008, 80, 6472–6479)2 covers solid phase extraction methods with a greater focus on their incorporation into integrated microfluidic systems.