cssi/SciSciGPT-SciSciNet huggingface dataset:
Holomorphic disks and genus bounds

We prove that, like the Seiberg{Witten monopole homology, the Heegaard Floer homology for a three-manifold determines its Thurston norm. As a consequence, we show that knot Floer homology detects the genus of a knot. This leads to new proofs of certain results previously obtained using Seiberg{Witten monopole Floer homology (in collaboration with Kronheimer and Mrowka). It also leads to a purely Morse-theoretic interpretation of the genus of a knot. The method of proof shows that the canonical element of Heegaard Floer homology associated to a weakly symplectically llable contact structure is non-trivial. In particular, for certain three-manifolds, Heegaard Floer homology gives obstructions to the existence of taut foliations.
ON THE RATIONALITY OF COMMON STOCK RETURN VOLATILITY

This paper derives the relationship between the population unconditional variance of common stock returns and the variance of expected returns conditional on a well-specified information set. As a consequence, a lower bound is obtained for the variance of common stock returns. The sample counterpart of this bound is then empirically tested against the sample variance of returns. The paper's main conclusion can be stated as follows: the observed volatility of real (inflation-adjusted) common stock returns is not “irrationally” large. The paper admits of this conclusion because the point estimate of the lower-bound variance derived in this model is actually larger than the point estimate of common stock return volatility. However, since these point estimates are found to have a statistically insignificant difference, equality of the two variances cannot be ruled out. Hence, “rationality” of common stock returns—as implied by a utility-based valuation conditional on a specified information set—cannot be rejected.
Retroactivity and Prospectivity of Judgments in American Law

In every American jurisdiction, new rules of law announced by a court are presumed to have retrospective effect – that is, they are presumed to apply to events occurring before the date of judgment. There are, however, exceptions in certain cases where a court believes that application of the new rule will upset serious and reasonable reliance on the prior state of the law. This chapter summarizes these exceptional cases. It shows that the proper occasions for issuing exclusively or partially prospective judgments have varied over time and that there are still substantial differences in approach according to the particular jurisdiction and the kind of law under consideration. The chapter concludes with a brief survey of some of the still unresolved jurisprudential and constitutional problems raised by recognition of the power of courts to issue non-retroactive judgments.
Airframe noise - The next aircraft noise barrier

Progress in quieting the commercial aviation fleet has been achieved by reducing the noise generated by jet engines. Recent tests have indicated that noise produced by airflow over aircraft surfaces (lifting surfaces, landing gear, flaps, and cavities) is only 8 to 10 EPNdB below certification requirements for current aircraft and will likely be a design consideration for aircraft of the future as engines become still quieter. This paper reviews the state of the art for understanding, predicting, and control of airframe noise. Levels and spectral content of the noise, correlation with important variables, and noise generation mechansims are discussed. The noise floors for future aircraft, the direction of research projects, and likely impact of this new technology on aircraft design are indicated.
A Catalog of Nearby Poor Clusters of Galaxies

A catalog of 732 optically selected, nearby poor clusters of galaxies covering the entire sky north of -3° declination is presented. The poor clusters, called WBL clusters, were identified as concentrations of three or more galaxies with photographic magnitudes brighter than 15.7, possessing a galaxy surface overdensity of 104/3. These criteria are consistent with those used in the identification of the original Yerkes poor clusters, and this new catalog substantially increases the sample size of such objects. These poor clusters cover the entire range of galaxy associations up to and including Abell clusters, systematically including poor and rich galaxy systems spanning over 3 orders of magnitude in the cluster mass function. As a result, this new catalog contains a greater diversity of richness and structures than other group catalogs, such as the Hickson and Yerkes catalogs. The information on individual galaxies includes redshifts and cross-references to other galaxy catalogs. The entries for the clusters include redshift (where available) and cross-references to other group and cluster catalogs.
New Primary Battery Systems

Abstract The search for new primary battery systems with improved performance characteristics in terms of higher watt-hours per pound or per cubic inch or at lower temperatures has been centered on those systems which can utilize high energy density electrode materials such as lithium, magnesium, or aluminum. Much of the effort has been in the area of obtaining compatible electrolytes, especially those of the nonaqueous type, for use with such electrode materials. To date, results indicate that the conductivity of the organic electrolytes will be well below that of aqueous solutions. Half cell studies have been performed on several of the more promising electrode-electrolyte combinations. Of the various systems being investigated to determine their suitability for operating over a wide temperature range, especially at the lower temperature, the magnesium-liquid ammonia system appears to be one of the most promising. Performance data are given for this system. The advantages, disadvantages and problem areas are indicated for the various systems covered in the paper.
Environmental Uncertainty and IT Infrastructure Governance: A Curvilinear Relationship

Extant research considers the IT governance choice to be a trade-off between the cost-efficiency of centralization and the responsiveness provided by local information processing. This view predicts that firms tend to decentralize IT governance in more uncertain environments. We investigate this issue by studying the relationship between environmental uncertainty and IT infrastructure governance in a sample of business units from Fortune 1000 companies. The key proposition in this paper is that the relationship between environmental uncertainty and decentralization in IT infrastructure governance is best characterized as a curvilinear relationship. That is, when environmental uncertainty increases from low to high, firms tend to first decentralize their IT infrastructure decisions to the business units to enhance their responsiveness; and then centralize their IT infrastructure decisions to the headquarters as uncertainty increases further, to achieve the benefits of coordination and to mitigate the potential agency problem in uncertain environments. Moreover, the study proposes that business unrelatedness between business units and their headquarters moderates the curvilinear relationship between environmental uncertainty and IT infrastructure governance. We find that both the propositions are supported by the data.
Photodetection in Silicon Beyond the Band Edge with Surface States

Silicon is an extremely attractive material platform for integrated optics at telecommunications wavelengths, particularly for integration with CMOS circuits. Developing detectors and electrically pumped lasers at telecom wavelengths are the two main technological hurdles before silicon can become a comprehensive platform for integrated optics. We report on the generation of free carriers in unimplanted SOI ridge waveguides, which we attribute to surface state absorption. By electrically contacting the waveguides, a photodetector with a responsivity of 36 mA/W and quantum efficiency of 2.8% is demonstrated. The photoconductive effect is shown to have minimal falloff at speeds of up to 60 Mhz.
Public policies and saving in developing countries

This paper draws on estimates of consumption functions for 13 developing countries to analyze the effectiveness of public policy in raising saving. First, it provides evidence from time-series and panel data on how liquidity constraints affect consumption functions. This suggests that a rise in public saving does not produce an equal reduction in private saving. Second, it presents direct evidence of the link between private consumption and government saving. These show that indirect effects of public policies on private saving are negligible, but that cuts in current public spending and current tax hikes significantly affect private saving. Increasing public saving by cutting current-period public expenditures by $1 reduces private saving by only 16 to 50 cents. Permanent cuts in public spending reduce private saving by 47 to 50 cents. A higher permanent tax hike has less of an effect on private saving than a transitory tax hike. For each $1 increase in permanent taxes, private saving declines only 23 to 26 cents. Increasing only current-period taxes reduces private saving between 48 and 65 cents. Increasing taxes and improving tax compliance are the most efficient ways to reduce public deficits when traditional tax revenue is low and inefficient tax levies are high and widespread. Finally, public policy can help raise private saving and make their use more efficient by providing a macroeconomic framework in which inflation is low and incentives are predictable.
Epistemic conditions for rationalizability

In this paper I present conditions, not involving common knowledge of rationality, that lead to (correlated) rationalizability. The basic observation is that, if the actual world belongs to a set of states where the set Z of action profiles is played, everyone is rational and it is mutual knowledge that the action profiles played are in Z, then the actions played at the actual world are rationalizable actions. Alternatively, if at the actual world the support of the conjecture of player i is Di, there is mutual knowledge of: (i) the game being played, (ii) that the players are rational, and (iii) that for every i the support of the conjecture of player i is contained in Di, then every strategy in the support of the conjectures is rationalizable. The results do not require common knowledge of anything and are valid for games with any number of players.
Analysis of Choroidal Thickness in Age-Related Macular Degeneration Using Spectral-Domain Optical Coherence Tomography

Purpose To understand the relationship between choroidal thickness and various disease factors in patients with age-related macular degeneration (AMD) using spectral-domain optical coherence tomography. Design Cross-sectional, retrospective analysis. Methods Fifty-seven eyes of 47 patients with wet and dry AMD seen between November 2009 and January 2010 at the New England Eye Center, Boston, Massachusetts, were analyzed. Choroidal thickness was measured by 2 independent observers at 11 sites with high-definition horizontal 1-line raster scans through the foveal center. A retrospective chart review was performed to obtain data concerning duration of disease, number of intravitreal anti–vascular endothelial growth factor injections, visual acuity, lens status, and concomitant retinal pathologic features. The Pearson correlation and Student t test were used for statistical analysis for assessment of choroidal thickness changes in wet and dry AMD. Results The choroid in eyes with wet and dry AMD demonstrated a wide range of thicknesses above and below the normal mean (range, 77.5 to 399.5 μm; standard deviation [SD], 90.2). Nearly one third (33.3%) of the eyes with AMD measured less than 1 SD below the mean. Eyes with wet AMD demonstrated a mean subfoveal choroidal thickness of 194.6 μm (SD, 88.4; n=40) compared with 213.4 μm (SD, 92.2; n=17) in the dry AMD group. The choroidal thickness in eyes with dry AMD was correlated inversely with age ( r = −0.703; P = .002); however, analysis of the number of intravitreal anti–vascular endothelial growth factor injections, number of years of disease, and visual acuity failed to demonstrate any significant correlations with choroidal thickness. Conclusions This study demonstrated that choroidal thickness can be measured by spectral-domain optical coherence tomography and that variable choroidal thickness exists among patients with the clinical diagnosis of wet and dry AMD. However, it is unclear at this time why in some eyes, choroidal thickness either increases or decreases with the disease. Further studies need to be carried out to understand the significance of choroidal thickness with respect to visual function and disease progression over time.
Celebesides A-C and theopapuamides B-D, depsipeptides from an Indonesian sponge that inhibit HIV-1 entry.

Six new depsipeptides belonging to two different structural classes, termed celebesides A-C and theopapuamides B-D, have been isolated from the marine sponge Siliquariaspongia mirabilis. Their structures were determined using extensive 2D NMR and ESI-MS/MS techniques. Celebesides are unusual cyclic depsipeptides that comprise a polyketide moiety and five amino acid residues, including an uncommon 3-carbamoyl threonine, and a phosphoserine residue in celebesides A and B. Theopapuamides B-D are undecapeptides with an N-terminal fatty acid moiety containing two previously unreported amino acids, 3-acetamido-2-aminopropanoic acid and 4-amino-2,3-dihydroxy-5-methylhexanoic acid. The relative configuration of the polyketide moiety in celebesides was resolved by J-based analysis and quantum mechanical calculations, the results of which were self consistent. Celebeside A neutralized HIV-1 in a single round infectivity assay with an IC50 value of 1.9 ± 0.4 μg/mL while the non-phosphorylated analog celebeside C was inactive at concentrations as high as 50 μg/mL. Theopapuamides A-C showed cytotoxicity against human colon carcinoma (HCT-116) cells with IC50 values between 2.1 and 4.0 μg/mL, and exhibited strong antifungal activity against wildtype and amphotericin B-resistant strains of Candida albicans at loads of 1-5 μg/disk.
Electrical Characterization of High-Speed Interconnects with a Parallel Three-Dimensional Finite-Difference Time-Domain Algorithm:

Although the Finite Difference Time- Domain (FDTD) method is over 25 years old, its use for the analysis of crosstalk, propagation delay, and pulse distortion of signals on interconnects in high-speed integrated circuits is relatively recent. With the development of faster computers, the use of FDTD has become more widespread because it has shown itself to be an efficient tool for the full-wave modeling of complicated microstrip circuit interconnects. In this paper, we address the parallelization of the FDTD method on multi-dimensional processor meshes mapped onto a hypercube multiprocessor. The use of parallelization is a natural step for the modeling of circuits because of the tremendous computational requirements to simulate even the simplest interconnect geometries. Experimental results on the Intel iPSC/860 hypercube are given which demonstrate a linear speedup in computation time.
Predicting folding pathways between RNA conformational structures guided by RNA stacks.

Accurately predicting low energy barrier folding pathways between conformational secondary structures of an RNA molecule can provide valuable information for understanding its catalytic and regulatory functions. Most existing heuristic algorithms guide the construction of folding pathways by free energies of intermediate structures in the next move during the folding. However due to the size and ruggedness of RNA energy landscape, energy-guided search can become trapped in local optima. In this paper, we propose an algorithm that guides the construction of folding pathways through the formation and destruction of RNA stacks. Guiding the construction of folding pathways by coarse grained movements of RNA stacks can help reduce the search space and make it easier to jump out of local optima. RNAEAPath is able to find lower energy barrier folding pathways between secondary structures of conformational switches and outperforms the existing heuristic algorithms in most test cases. RNAEAPath provides an alternate approach for predicting low-barrier folding pathways between RNA conformational secondary structures. The source code of RNAEAPath and the test data sets are available at http://genome.ucf.edu/RNAEAPath .
The human intranet: where swarms and humans meet

A Human Intranet is envisioned as an open scalable platform that seamlessly integrates an ever-increasing number of sensor, actuation, computation, storage, communication and energy nodes located on, in, or around the human body acting in symbiosis with the functions provided by the body itself. This may fundamentally alter the ways humans operate, and interact with the physical world around them. It all starts with concepts that find their roots in the Internet of Things (IoT) and swarm technologies.
Scott E. Forbush 1904”1984

Scott E. Forbush, a pioneer in cosmic ray research, was the quintessential geophysicist's geophysicist. Until, on the eve of his 80th birthday, he succumbed to pneumonia, he maintained an abiding interest in the continued reliable operation of the three remaining cosmic ray ionization chambers of the worldwide network that he had set up in the mid 1930s. No one could have predicted, when the first instrument at Cheltenham, Md. commenced operation in 1936, that Forbush was destined to discover most of the important multifarious time variations of cosmic rays that were accessible to his classic detectors
On the nature of electroactive sites in clay-modified electrodes

Abstract The electrochemical properties of montmorillonite clay films deposited on pyrolytic graphite electrodes have been studied by cyclic voltammetry in order to elucidate the nature of the electroactive sites. Electrodes coated with pre-exchanged ML2+3 -montmorillonite (M = Fe, Ru, Os and L = bpy; M = Fe and L = phen), and MV2+-montmorillonite (MV2+ = methylviologen) do not exhibit a voltammetric response when immersed in solutions containing only electrolyte. This result shows that the cations bound electrostatically to the exchange sites, whether intercalated within the galleries or held at the external surfaces, are rigorously electroinactive. However, these films incorporate ML2+3 and MV2+ ions from solution readily and exhibit voltammetric responses characteristic of diffusional processes. Os(bpy)32+-exchanged montmorillonite films immersed in Fe(bpy)32+ solutions show a voltammogram only for the Fe(bpy)33+/2+ couple, and peak current values indicate that Fe(bpy)33+ does not accept electrons from Os(bpy)32+ gallery cations. The electroactivity for films immersed in ML32+ or MV2+ solutions is attributed in part to cations which are bound at the clay surface in excess of the cation exchange capacity by an ion pairing mechanism. Experiments using synthetic clays of different particle sizes suggest that binding of the ion pairs is related to the presence of edge surface sites.
Surfaces in 4-Manifolds

In this paper we introduce a technique, called rim surgery, which can change a smooth embedding ofan orientable surf ace Σ ofpositive genus and nonnegative self-intersection in a smooth 4-manifold X while leaving the topological embedding unchanged. This is accomplished by replacing the tubular neighborhood ofa particular nullhomologous torus in X with S 1 × E(K), where E(K) is the exterior ofa knot K ⊂ S 3 . The smooth change can be detected easily for certain pairs (X,Σ) called SW-pairs. For example, (X,Σ) is an SW-pair if Σ is a symplectically and primitively embedded surface with positive genus and nonnegative self-intersection in a simply connected symplectic 4-manifold X.W e prove the following theorem: Theorem. Consider any SW-pair (X,Σ). For each knot K ⊂ S 3 there is a surface ΣK ⊂ X such that the pairs (X,ΣK) and (X,Σ) are homeomorphic. However, if K1 and K2 are two knots for which there is a diffeomorphism of pairs (X,ΣK1 ) → (X,ΣK2 ), then their Alexander polynomials are equal: ∆K1 (t )= ∆K2 (t).
Natural products via Reetz chemistry synthesis of (+/-)-Cuparene

Support by way of a Bristol-Myers Squibb Award of Research Corporation is gratefully acknowledged. Paul Schupf and the National Science Foundation are acknowledged for their support of the Colby Chemistry Computational Facilities. The Camille and Henry Dreyfus Foundation, and Glaxo-Wellcome Foundation are also acknowledged for their support. Dr. Joe Sears, Montana State University Mass Spectrometry facility, Bozeman, MT, supplied HRMS data. We also acknowledge the continued support of the Science Division of Colby College. S.V.S and B.L.J acknowledge support from the general research fund of the University of Maine.
Estimation Risk, Information, and the Conditional CAPM: Theory and Evidence

We theoretically and empirically investigate the role of information on the cross section of stock returns and firms' cost of capital when investors face estimation risk and learn from noisy signals of uncertain quality. The resultant equilibrium is an information-dependent conditional CAPM. We find strong empirical support for the model. Innovations in market volatility, oil prices, exchange rates, and dispersion of analysts' forecasts not only help explain the cross section of stock returns, but their influence depends on the stock's systematic estimation risk. Moreover, dividend and share repurchase initiations have significant downward announcement effects on estimated betas and their standard errors. (JEL D83, D92, E22) How investors process new return-related information and how this information affects equilibrium asset prices is a central issue in finance; it is of substantial interest not only to financial economists seeking to understand the informational efficiency of security prices, but also to investment practitioners who must make investment decisions in the face of continually arriving information. In the textbook capital asset pricing model (CAPM), which assumes that the investment opportunity set is common knowledge, prices simply adjust to new information so as to fall along the new security pricing line. However, this model of information absorption (in security markets) is not satisfactory from
Asymptotic dimension of finitely presented groups

We prove that if a finitely presented group is one-ended, then its asymptotic dimension is greater than 1. It follows that a finitely presented group of asymptotic dimension 1 is virtually free.
Resumption strategies for interrupted programming tasks

Interrupted and blocked tasks are a daily reality for professional programmers. Unfortunately, the strategies programmers use to recover lost knowledge and rebuild context when resuming work have not yet been well studied. In this paper, we describe an exploratory analysis performed on 10,000 recorded sessions of 86 programmers and a survey of 414 programmers to understand the various strategies and coping mechanisms developers use to manage interrupted programming tasks. Based on the analysis, we propose a framework for understanding these strategies and suggest how task resumption might be better supported in future development tools. The results suggest that task resumption is a frequent and persistent problem for developers. For example, we find that only 10% of the sessions have programming activity resume in less than 1 min after an interruption, only 7% of the programming sessions involve no navigation to other locations prior to editing. We also found that programmers use multiple coping mechanisms to recover task context when resuming work.
Faculty Perceptions of Interactive Television Instruction

Abstract As competing distance education technologies emerge, it is important for universities to assess their instructional delivery systems to determine their impact on both students and faculty. In this study, the authors assessed the impact of 1 distance education technology, interactive television (ITV), on faculty perceptions. The authors asked faculty members for information on their attitudes toward faculty preparation and performance, student preparation and performance, classroom participation and interaction, and delivery and instruction issues. Results showed that experienced ITV faculty members and female faculty members held generally positive perceptions of ITV and that business faculty members were less positive than their nonbusiness colleagues.
A New Computational Method for Free Surface Problems

A new technique, called the surface velocity correction (SVC) technique, is developed to track a free surface such as a liquid–vapor interface. The SVC is a computationally inexpensive and accurate method to capture interfacial fluid phenomena. This method uses a finite-volume technique to discretize the governing equations, and a semi-Legrangian mesh to locate the interface between two fluids. The effectiveness of this technique is demonstrated through several classical examples and the results are also compared to both analytical and volume-of-fluid (VOF) solutions. The examples include the shape of a meniscus in a capillary tube in mechanical equilibrium, the rise of a meniscus in a capillary tube, and the instability growth of a free-flowing cylindrical column of fluid.
Laboratory Evaluation of Long-Term Draindown of Porous Asphalt Mixtures

AbstractLong-term draindown is the term adopted in this study to describe the downward flow of binder in a porous asphalt mixture due to the force of gravity at high temperatures experienced during service, especially in warmer climates. The concept of long-term draindown has been qualitatively noted in field observations of porous asphalt mixtures, including open graded friction courses (OGFC). This research quantified the long-term draindown of three different OGFC mixtures by measuring the permeability of the mixes throughout an 84-day conditioning period at 60°C. The results showed that the permeability of all three mixtures decreased over the first 56 days and then leveled off or increased for the remaining 28 days. To verify that the permeability reduction was due to binder draindown, the distribution of binder content of randomly selected specimens was measured. The results from this study indicated that cellulose fibers did not have any influence on the long-term draindown of the mixtures evaluate...
Kinetics of CN radical reactions with formaldehyde and 1,3,5‐trioxane

Absolute rate constants were measured for the reaction CN + CH2O over the temperature range 297–673 K and CN + 1,3,5-trioxane over the range of 297–600 K by the laser photolysis/laser induced fluorescence technique. The rate constants for these reactions can be effectively represented, in units of cm3/s, by: k(CH2O) = 2.82 × 10−19T2.72 exp(718/T), and k(1,3,5-trioxane) = 1.39 × 10−23T4.26 exp(1333/T), respectively. Transition state theory calculations were able to fit the temperature dependence of the CN + CH2O rates relatively well. We attempted to correlate the CN reaction rate with CH2O and other molecules which occur through simple abstraction with the corresponding OH reaction rates, yielding only a qualitative linear correlation for a majority of the processes. The reactions which deviated significantly from linearity include those which contain strong dipoles, highlighting the significant role long-range attractive forces play in CN and OH reactions. Using a simple electrostatic potential, cross-sections were determined for reactions with CN. No linear correlation was found between the calculated and experimental cross sections for the majority of the reactions studied. © 1993 John Wiley & Sons, Inc.
[Ne V] Emission in Optically Classified Starbursts

Detecting active galactic nuclei (AGNs) in galaxies dominated by powerful nuclear star formation and extinction effects poses a unique challenge. Due to the longer wavelength emission and the ionization potential of Ne4+, infrared [Ne V] emission lines are thought to be excellent AGN diagnostics. However, stellar evolution models predict that Wolf-Rayet stars in young stellar clusters emit significant numbers of photons capable of creating Ne4+. Recent observations of [Ne V] emission in optically classified starburst galaxies require us to investigate whether [Ne V] can arise from star formation activity and not an AGN. In this work, we calculate the optical and IR spectrum of gas exposed to a young starburst and AGN SED. We find: (1) a range of parameters where [Ne V] emission can be explained solely by star formation and (2) a range of relative AGN to starburst luminosities that reproduces the [Ne V] observations, yet leaves the optical spectrum looking like a starburst. We also find that infrared emission-line diagnostics are much more sensitive to the AGNs than optical diagnostics, particularly for weak AGNs. We apply our model to the optically classified, yet [Ne V] emitting, starburst galaxy NGC 3621. We find, when taking the infrared and optical spectrum into account, ~30%-50% of the galaxy's total luminosity is due to an AGN. Our calculations show that [Ne V] emission is almost always the result of AGN activity. The models presented in this work can be used to determine the AGN contribution to a galaxy's power output.
Effects of electrostatic correlations on electrokinetic phenomena

The classical theory of electrokinetic phenomena is based on the mean-field approximation that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes, or solvent-free ionic liquids, where the mean-field approximation breaks down. A fourth-order modified Poisson equation is developed that captures the essential features in a simple continuum framework. The model is derived as a gradient approximation for nonlocal electrostatics of interacting effective charges, where the permittivity becomes a differential operator, scaled by a correlation length. The theory is able to capture subtle aspects of molecular simulations and allows for simple calculations of electrokinetic flows in correlated ionic fluids. Charge-density oscillations tend to reduce electro-osmotic flow and streaming current, and overscreening of surface charge can lead to flow reversal. These effects also help to explain the suppression of induced-charge electrokinetic phenomena at high salt concentrations.
On the failure of subadditivity of the Wigner-Yanase entropy

It was recently shown by Hansen that the Wigner–Yanase entropy is, for general states of quantum systems, not subadditive with respect to decomposition into two subsystems, although this property is known to hold for pure states. We investigate the question whether the weaker property of subadditivity for pure states with respect to decomposition into more than two subsystems holds. This property would have interesting applications in quantum chemistry. We show, however, that it does not hold in general, and provide a counterexample.
The union of balls and its dual shape

Efficient algorithms are described for computing topological, combinatorial, and metric properties of the union of finitely many spherical balls in ?d. These algorithms are based on a simplicial complex dual to a decomposition of the union of balls using Voronoi cells, and on short inclusion-exclusion formulas derived from this complex. The algorithms are most relevant in ?3 where unions of finitely many balls are commonly used as models of molecules.
Products and h-homogeneity

Abstract Building on work of Terada, we prove that h-homogeneity is productive in the class of zero-dimensional spaces. Then, by generalizing a result of Motorov, we show that for every non-empty zero-dimensional space X there exists a non-empty zero-dimensional space Y such that X × Y is h-homogeneous. Also, we simultaneously generalize results of Motorov and Terada by showing that if X is a space such that the isolated points are dense then X κ is h-homogeneous for every infinite cardinal κ. Finally, we show that a question of Terada (whether X ω is h-homogeneous for every zero-dimensional first-countable X) is equivalent to a question of Motorov (whether such an infinite power is always divisible by 2) and give some partial answers.
Optimized Measurements of Unmanned-Air-Vehicle Mass Moment of Inertia with a Bifilar Pendulum

A bifilar (two-wire) pendulum is a torsional pendulum consisting of a test object suspended by two thin parallel wires. The pendulum oscillates about the vertical axis. The restoring torque of the bifilar pendulum is provided by the gravitational force as rotations from the rest state cause the test object to raise slightly. The mass moment of inertia is computed using dynamic modeling, measurements of the oscillation period, and the physical dimensions of the bifilar pendulum such as the length and separation displacement of the pendulum wires. A simulation technique is described that improves estimates of the mass moment of inertia by considering the nonlinear effects of damping and large angular displacements. An analysis of the error variance of mass moment of inertia measurements is also described. The resulting expression for the error variance is used to optimize the physical parameters of the bifilar pendulum to obtain the moment of inertia measurement with the minimum error variance. Monte Carlo simulations were used to validate the parameter optimization technique. Experimental results are presented for a uniform-density test object for which the moment of inertia is straightforward to compute from geometric considerations. Results are also presented for a small unmanned air vehicle, which was the intended application for this moment of inertia measurement technique.
Evaluation of models to predict insolation on tilted surfaces

An empirical study was performed to evaluate the validity of various insolation models which employ either an isotropic or an anisotropic distribution approximation for sky light when predicting insolation on tilted surfaces. Data sets of measured hourly insolation values were obtained over a 6-month period using pyranometers which received diffuse and total solar radiation on a horizontal plane and total radiation on surfaces tilted toward the equator at 37 degrees and 60 degrees angles above the horizon. Data on the horizontal surfaces were used in the insolation models to predict insolation on the tilted surface; comparisons of measured vs calculated insolation on the tilted surface were examined to test the validity of the sky light approximations. It was found that the Liu-Jordan isotropic distribution model provides a good fit to empirical data under overcast skies but underestimates the amount of solar radiation incident on tilted surfaces under clear and partly cloudy conditions.
The treatment of bias in the square-root information filter/smoother

The Dyer-McReynolds square-root information filter (SRIF) is rederived, using recursive least-square arguments. The result is applied to a system composed partly of biases. The filter sensitivity matrix, computed covariance, and consider covariance for this augmented system are reviewed. A new computationally attractive representation for the smoothed estimates, in terms of a smoothed sensitivity matrix and a smoothed computed covariance is presented.
Contemporaneous Dual Catalysis: Chemoselective Cross-Coupling of Catalytic Vanadium–Allenoate and π-Allylpalladium Intermediates

This paper presents a detailed investigation of a dual catalytic system that combines a vanadium-catalyzed Meyer–Schuster rearrangement and a palladium-catalyzed allylic alkylation. The implementation of this novel reaction relies on matching the formation rates of vanadium–allenoate and π-allylpalladium intermediates with their bimolecular coupling rate in order to minimize the undesired protonation or O-alkylation of the catalytically generated intermediates. Chemoselectivity in this dual catalytic process was successfully achieved by adjusting ligand structure and catalyst loading ratios of the vanadium and palladium catalysts. A great range of coupling partners for both the propargyl alcohol and allyl carbonate components are readily accommodated in this new transformation, which in turn provides a novel avenue to a variety of α-allylated α,β-unsaturated ketones, esters, and amides in moderate to excellent isolated yields.
Identifying Gamma‐Ray Burst Remnants in Nearby Galaxies

We study the spectral signatures arising from cooling and recombination of an interstellar medium whose equilibrium state has been altered over D100 pc by the radiation of a gamma-ray burst (GRB) and its afterglow. We identify signatures in the line diagnostics that are indicative of a photoionized GRB remnant which is yr old. We estimate that at least a few such remnants should be (5 ) 104 detectable in the Virgo Cluster of galaxies. If the gamma-ray emission from GRBs is beamed to a frac- tion of their sky, then the expected number of Virgo remnants is larger by a factor of Virgo f b f b. remnants can be resolved with arcsecond imaging and are likely to be center-—lled using narrowband —lters of high-ionization lines (such as (O III) j5007 or He II j4686) and limb-brightened for low- ionization lines (such as (S II) j6717). The nonrelativistic blast wave might be visible separately, since it does not reach the outer edge of these young photoionized remnants. The remnants should show evi- dence for ionization cones if the prompt or afterglow UV emission from GRBs is beamed. Subject headings: galaxies: clusters: individual (Virgo) ¨ gamma rays: burstsISM: general
Designing software for the minicomputer business data processing environment: a case history

The design of software for the minicomputer business data processing environments poses significant practical design problems. This paper deals with the history of the design and implementation of a specific system for that environment. Changes in the system design due to problems in the operational environment are examined. Conclusions are made concerning the design of the system.
Enhanced subleading structure functions in semileptonic B decay

Abstract The charged lepton spectrum in semileptonic B→X u l ν decay near maximal lepton energy receives important corrections from subleading structure functions that are formally suppressed by powers of ΛQCD/mb but are enhanced by numerical factors. We investigate the series of higher order terms which smear over a region of width ΔEl∼ΛQCD near the endpoint the contributions proportional to δ(El−mb/2) times (i) the matrix element of the chromomagnetic operator, and (ii) four-quark operators. These contribute to the total rate at the few percent level, but affect the endpoint region much more significantly. Implications for the determination of |Vub| are discussed.
Not-so-classical mechanics: unexpected symmetries of classical motion

Nous passons en revue les sujets d'interel recents dans les systemes dynamiques de Lagrange et de Hamilton, incluant les discussions disponibles concernant la regularisation du probleme du potentiel central. Sont couverts ici les Lagrangiens et Hamiltoniens non equivalents, les constantes du mouvement dans un potentiel central, une discussion generale des Lagrangiens et Hamiltoniens d'ordre plus eleve, avec iles exemples tires de la mecanique quanlique de Bohm, de l'equation de Korteweg-de Vries et de l'equation logistique, les theories de jauge de la mecanique de Newton, le spin classique, les nombres de Grassmann et la pseudo-mecanique.
Effect of niobium interlayer on high-temperature sliding friction and wear of silver films on alumina

In this study, we investigated the effect of a thin Nb bonding layer (15–20 nm thick) on the high-temperature sliding friction and wear performance of Ag films (∼ 1.5 μm thick) produced on α-alumina (Al2O3) substrates by ion-beam assisted deposition (IBAD). The friction coefficients of Al2O3 balls against the Ag-coated Al2O3 flats were 0.32 to 0.5 as opposed to 0.8 to 1.1 against the uncoated flats. Furthermore, these Ag films reduced the wear rates of Al2O3 balls by factors of 25 to ∼ 2000, depending on test temperature. Wear of Ag-coated Al2O3 flats was hard to measure after tests at temperatures up to 400°C. At much higher temperatures (e.g., 600°C), these Ag films (without a Nb layer) were removed from the sliding surfaces and lost their effectiveness; however, Ag films with the Nb bonding layer remained intact on the sliding surfaces of the Al2O3 substrates even at 600°C and continued to impart low friction and low wear.
A Practical Factorization of a Schur Complement for PDE-Constrained Distributed Optimal Control

A distributed optimal control problem with the constraint of a linear elliptic partial differential equation is considered. A necessary optimality condition for this problem forms a saddle point system, the efficient and accurate solution of which is crucial. A new factorization of the Schur complement for such a system is proposed and its characteristics discussed. The factorization introduces two complex factors that are complex conjugate to each other. The proposed solution methodology involves the application of a parallel linear domain decomposition solver--FETI-DPH--for the solution of the subproblems with the complex factors. Numerical properties of FETI-DPH in this context are demonstrated, including numerical and parallel scalability and regularization dependence. The new factorization can be used to solve Schur complement systems arising in both range-space and full-space formulations. In both cases, numerical results indicate that the complex factorization is promising. Especially, in the full-space method with the new factorization, the number of iterations required for convergence is independent of regularization parameter values.
Spiders for rank 2 Lie algebras

A spider is an axiomatization of the representation theory of a group, quantum group, Lie algebra, or other group or group-like object. It is also known as a spherical category, or a strict, monoidal category with a few extra properties, or by several other names. A recently useful point of view, developed by other authors, of the representation theory of sl(2) has been to present it as a spider by generators and relations. That is, one has an algebraic spider, defined by invariants of linear representations, and one identifies it as isomorphic to a combinatorial spider, given by generators and relations. We generalize this approach to the rank 2 simple Lie algebras, namelyA 2,B 2, andG 2. Our combinatorial rank 2 spiders yield bases for invariant spaces which are probably related to Lusztig's canonical bases, and they are useful for computing quantities such as generalized 6j-symbols and quantum link invariants. Their definition originates in definitions of the rank 2 quantum link invariants that were discovered independently by the author and Francois Jaeger.
Small optimal Margulis numbers force upper volume bounds

If $\lambda$ is a positive real number strictly less than $\log3$, there is a positive number $V_\lambda$ such that every orientable hyperbolic 3-manifold of volume greater than $V_\lambda$ admits $\lambda$ as a Margulis number. If $\lambda<(\log3)/2$, such a $V_\lambda$ can be specified explicitly, and is bounded above by $$\lambda\bigg(6+\frac{880}{\log3-2\lambda}\log{1\over\log3-2\lambda}\bigg),$$ where $\log$ denotes the natural logarithm. These results imply that for $\lambda<\log3$, an orientable hyperbolic 3-manifold that does not have $\lambda$ as a Margulis number has a rank-2 subgroup of bounded index in its fundamental group, and in particular has a fundamental group of bounded rank. Again, the bounds in these corollaries can be made explicit if $\lambda<(\log3)/2$.
A General and Highly Selective Chelate-Controlled Intermolecular Oxidative Heck Reaction

A novel chelate-controlled intermolecular oxidative Heck reaction is reported that proceeds with a wide range of nonresonance stabilized α-olefin substrates and organoboron reagents to afford internal olefin products in good yields and outstanding regio- and E:Z stereoselectivities. Pd−H isomerization, common in many Heck reactions, is not observed under these mild, oxidative conditions. This is evidenced by outstanding E:Z selectivities (>20:1 in all cases examined), no erosion in optical purity for proximal stereogenic centers, and a tolerance for unprotected alcohols. Remarkably, a single metal/ligand combination, Pd/bis-sulfoxide complex 1, catalyzes this reaction over a broad range of coupling partners. Given the high selectivities and broad scope, we anticipate this intermolecular Heck reaction will find heightened use in complex molecule synthesis.
IMP dehydrogenase: structure, mechanism, and inhibition.

George Weber was among the first to recognize that extensive metabolic changes must underlie the unbridled proliferation of cancer cells 1. His molecular correlation hypothesis postulated that a defined set of key “pace-maker” enzymes are stringently linked to neoplastic transformation and progression, and that inhibition of these enzymes would provide an effective strategy for chemotherapy. Weber's subsequent discovery that inosine 5′-monophosphate dehydrogenase (IMPDH) is amplified in tumors and rapidly proliferating tissues provided the foundation for drug design targeting this enzyme 2. Though yet to achieve much success in the cancer arena, IMPDH inhibitors are now widely used in immunosuppressive and antiviral chemotherapy, and IMPDH may also be a target for antimicrobial drugs. Clinical relevance aside, IMPDH is a fascinating enzyme. It traverses several conformations while catalyzing two different chemical transformations, utilizing unusual chemical strategies to promote each reaction. Monovalent cations such as K+ activate IMPDH, possibly by acting as a molecular lubricant to facilitate these conformational changes. The biology of IMPDH also displays some surprising twists. IMPDH binds nucleic acids and is associated with polyribosomes 3-6, though the physiological role of this interaction also has not yet been elucidated. Perhaps most intriguing is the discovery that mutations in IMPDH are associated with hereditary retinal disease 7-9. These mutations cluster to a subdomain that is not required for enzymatic activity, and the function of this subdomain is currently under debate. This article will review recent work on the biochemistry of IMPDH, integrating structure, function and inhibition. Earlier reviews on this topic include references 10-12. Several more focused reviews have addressed IMPDH as a drug target for immunosuppressive 13, cancer 14,15, antiviral 16 and antimicrobial chemotherapy 17, specific classes of IMPDH inhibitors 18, advances in structure and mechanism 19 and the role of IMPDH in retinal disease 20,21. The reader is also directed to a collection of papers from the 2000 meeting, Inosine monophosphate dehydrogenase: a major therapeutic target 22.
Fuzzy Logic and the Resolution Principle

ABSTRACT The relationship between fuzzy logic and two-valued logic in the context of the first order predicate calculus is discussed. It is proved that if every clause in a set of clauses is something more than a “half-truth” and the most reliable clause has truth-value a and the most unreliable clause has truth-value b , then we are guaranteed that all the logical consequences obtained by repeatedly applying the resolution principle will have truth-value between a and b . The significance of this theorem is also discussed.