cssi/SciSciGPT-SciSciNet huggingface dataset:
Cryostatic stability equation

As regards recovery from a quench, boiling in narrow channels is shown to be qualitatively superior to pool boiling because the recovery heat flux equals the breakaway flux for narrow channels whereas the two are markedly different in pool boiling. A second advantage of channel boiling is that it is well understood and calculable whereas pool peak nucleate boiling heat flux has been adequately measured only for boiling from the top of an immersed heated body. Peak boiling from the bottom is much less and (probably) depends strongly on the extent of the bottom surface. Equations are presented by which one can calculate the critical boiling heat flux for parallel wall vertical channels subject to either natural convection or forced flow boiling, with one or both walls heated. The one-heated-wall forced flow equation is discussed with regard to design of a spiral wound solenoid (pancake magnet) having a slippery insulating tape between the windings.
Antimicrobial susceptibility testing of anaerobic bacteria

Antimicrobial therapy of anaerobic infections is usually predicted on the basis of known patterns of susceptibility of anaerobic bacteria to antimicrobial agents rather than on results of in vitro tests of individual isolates. Routine susceptibility testing of anaerobic bacteria is not recommended, but there are instances of serious infection, i.e., endocarditis, or specific infecting organisms, e.g., Bacteroides fragilis, when in vitro testing of the specific infecting organism is indicated. No standard method has yet been accepted. Methods presently recommended are agar dilution or broth dilution tests. Other methods currently being evaluated are agar (disc) diffusion, broth-disc, and simplified broth and agar dilution tests. The advantages and limitations of the various methods are discussed.
Flow Visualizations and Measurements of a Three-Dimensional Supersonic Separated Flow

The flow along the afterbody and in the base region of a circular cylinder with a length-to-radius ratio of 3.0 aligned at a 10-deg angle of attack to a nominal Mach 2.5 freestream has been investigated experimentally. The objective is to better understand the mechanisms that control base flow for supersonic bodies with a nonzero-angle-of-attack orientation. Laser Doppler velocimetry measurements were conducted in the incoming boundary layer to quantify the initial conditions at the onset of three-dimensional behavior. Schlieren and Mie scattering visualizations were obtained to discern governing flow features and to image the large-scale turbulent structures of this separated flow. Surface oil-streak visualizations were obtained to determine the three dimensionality of the afterbody surface flow and to deduce the base surface flowfield. Pressure-sensitive paint measurements were completed to determine the spatial evolution of surface pressure along the cylindrical body at angle of attack and to determine the change in base pressure caused by inclination of the body
SIMPL-2: (SIMulated Profiles from the Layout-Version 2)

SIMPL is a computer-aided-design (CAD) tool for simulating the cross-sectional profile of integrated circuits along an arbitrary cut-line drawn on the layout. The linked-list arbitrary polygonal data structure, process specification file, physical process algorithms, graphics display interface, and linking to external rigorous process simulators of SIMPL-2 are described. SIMPL-2 is capable of displaying in color two-dimensional process effects such as the bird's-beak, lateral diffusion, undercut in etching, and sidewall coverage in deposition, based on its linked-polygonal and grid-type databases. The device profile from the composite can be generated rapidly in several minutes on a VAX 11/780 using elementary internal physical process models. SIMPL-2 can also invoke more rigorous external process simulators through an interface for profile data and transfer of control, providing a heretofore missing link between layout-based CAD tools and process and device simulators. >
Incident beam polarization for laser Doppler velocimetry employing a sapphire cylindrical window

For laser Doppler velocimetry studies employing sapphire windows as optical access ports, the birefringency of sapphire produces an extra beam intersection volume which serves to effectively smear the acquired velocity flow field data. It is shown that for a cylindrical window geometry, the extra beam intersection volume may be eliminated with minimal decrease in the fringe visibility of the remaining intersection volume by suitably orienting the polarizations of the initial laser beams. For horizontally incident beams, these polarizations were measured at three intersection locations within the cylinder. It was found that the measured polarization angles agreed with the theoretical predictions.
Segmental and prosodic effects on coda glottalization

Abstract This paper examines effects of segmental context and prosodic phrasing on the occurrence of coda glottalization in American English. On the basis of acoustic data from six female speakers, it is argued that the main effect of following segmental context on the occurrence of coda glottalization is due to anticipatory coarticulation, with anticipation of following sonorant consonant articulations favoring the aerodynamic conditions for glottalized voicing. The cross-dialect propensity to have high coda glottalization rates before sonorant consonants can then be understood to arise as a phonetically natural consequence of normal coarticulation processes. This coarticulatory account is supported by the fact that when an intonation phrase (IP) boundary intervenes between the coda consonant and a following sonorant, the contextual effect on glottalization rates is weakened. Our data also suggest that, all else being equal, presence of an IP boundary favors the occurrence of glottalization. These patterns are compatible with an account in which a glottal constriction goal on the coda consonant is optional in the linguistic representation. The optionality of this goal is somewhat problematic for many models of phonetic knowledge, but the coarticulatory explanation of the sonorancy effect helps to insightfully simplify any account of the distribution of glottalization.
Finite element analysis of structural engineering problems using a viscoplastic model incorporating two back stresses

The feasibility of a viscoplastic model incorporating two back stresses and a drag strength is investigated for performing nonlinear finite element analyses of structural engineering problems. To demonstrate suitability for nonlinear structural analyses, the model is implemented into a finite element program and analyses for several uniaxial and multiaxial problems are performed. Good agreement is shown between the results obtained using the finite element implementation and those obtained experimentally. The advantages of using advanced viscoplastic models for performing nonlinear finite element analyses of structural components are indicated.
Dynamics of laser excitation, ionization and harmonic conversion in inert gas atoms

Studies of non-perturbative multiphoton processes in atoms in pulsed laser fields employ a single-active-electron (SAE) model which follows the time evolution of each valence electron in the frozen, mean-field of the remaining electrons, the nucleus and the laser field. The photoelectron and photon emission spectra, although related, are not identical. A simple two-step, quasi-classical model explains the differences and gives a more complete understanding of the strong field induced dynamics.
The determination of microcrystallite size by the small angle x‐ray technique in rayons

The scattering of x-rays at small angles by various rayons of high orientation was investi gated at various degrees of swelling.The occurrence of inflection points or maxima-minima in the scattering curves of these fibers at certain degrees of swelling is explained by interparticle interference in the densely packed condition.The experimental conditions necessary for a reliable determination of particle size (diameter of microcrystallites) for these fibers are derived from the results obtained, and particle sizes determined by this method are given.
On Hopf Algebras and Their Generalizations

We survey Hopf algebras and their generalizations. In particular, we compare and contrast three well-studied generalizations (quasi-Hopf algebras, weak Hopf algebras, and Hopf algebroids), and two newer ones (Hopf monads and hopfish algebras). Each of these notions was originally introduced for a specific purpose within a particular context; our discussion favors applicability to the theory of dynamical quantum groups. Throughout the note, we provide several definitions and examples in order to make this exposition accessible to readers with differing backgrounds.
Fixed exchange rates and trade

Abstract A classic argument for a fixed exchange rate is its promotion of trade. Empirical support for this, however, is mixed. While one branch of research consistently shows a small negative effect of exchange rate volatility on trade, another, more recent, branch presents evidence of a large positive impact of currency unions on trade. This paper helps resolve this disconnect. Our results, which use a new data-based classification of fixed exchange rate regimes, show a large, significant effect of a fixed exchange rate on bilateral trade between a base country and a country that pegs to it. These results suggest an economically relevant role for exchange rate regimes in trade determination since a significant amount of world trade is conducted between countries with fixed exchange rates.
Exact eigenvalue placement for two-time-scale discrete-time systems

Linear shift-invariant discrete-time systems satisfying the two-time-scale property are considered. A transformation matrix is formed and applied to the system to separate its slow and fast modes. Two subsystems are then defined, one for the slow modes and the other for the fast modes. An eigenvalue placement technique is proposed that will place the eigenvalues of the closed loop sub-systems at desired locations. The composite controller will also be formed for the original system.
Nonlinear Optical Probe of Tunable Surface Electrons on a Topological Insulator

We use ultrafast laser pulses to experimentally demonstrate that the second-order optical response of bulk single crystals of the topological insulator Bi(2)Se(3) is sensitive to its surface electrons. By performing surface doping dependence measurements as a function of photon polarization and sample orientation we show that second harmonic generation can simultaneously probe both the surface crystalline structure and the surface charge of Bi(2)Se(3). Furthermore, we find that second harmonic generation using circularly polarized photons reveals the time-reversal symmetry properties of the system and is surprisingly robust against surface charging, which makes it a promising tool for spectroscopic studies of topological surfaces and buried interfaces.
Water storage and early hydrous melting of the Martian mantle

Abstract We report an experimental investigation of the near-solidus phase equilibria of a water-saturated analog of the Martian mantle. Experiments were performed at low temperatures (700–920 °C) and high pressure (4–7 GPa) using multi-anvil apparatus and piston cylinder device (4 GPa). The results of this study are used to explore the role of water during early melting and chemical differentiation of Mars, and to further our understanding of the near-solidus behavior in planetary mantle compositions at high pressure. Water has a significant effect on the temperature of melting and, therefore, on accretion and subsequent differentiation processes. Experiments locate the wet solidus at ∼800 °C, and is isothermal between 4 GPa and 7 GPa. The Martian primitive mantle can store significant amounts of water in hydrous minerals stable near the solidus. Humite-group minerals and phase E represent the most abundant hydrous minerals stable in the 4–7 GPa pressure range. The amount of water that can be stored in the mantle and mobilized during melting ranges from 1 to up to 4 wt% near the wet solidus. We discuss thermal models of Mars accretion where the planet formed very rapidly and early on in solar system history. We incorporate the time constraint of Dauphas and Pourmand (2011) that Mars had accreted to 50% of its present mass in 1.8 Myr and include the effects of 26Al radioactive decay and heat supplied by rapid accretion. When accretion has reached 30% of Mars current mass (∼70% of its present size), melting starts, and extends from 100 to 720 km depth. Below this melt layer, water can still be bound in crystalline solids. The critical stage is at 50% accretion (∼80% of its size), where Mars is above the wet and dry solidi with most of its interior melted. This is earlier in the accretion process than what would be predicted from dry melting. We suggest that water may have promoted early core formation on Mars and rapidly extended melting over a large portion of Mars interior.
Fluorotamoxifen. A Caveat on the Generality of Electrophilic Destannylation

Abstract A one-step synthesis of fluorotamoxifen from tamnoxifen is described. Attempts to achieve synthesis of the title compound by fluorodestannylation or transmetallation were unsuccessful.
Synthetic studies toward the citrinadins: enantioselective preparation of an advanced spirooxindole intermediate

This manuscript describes the enantioselective preparation of a spirooxindole that is suited for advancedment to either Citrinadin A or B.
Asymmetric Synthesis of α-Allyl-α-Aryl α-Amino Acids by Tandem Alkylation/π-Allylation of α-Iminoesters

The first asymmetric synthesis of α-allyl-α-aryl α-amino acids by means of a three-component coupling of α-iminoesters, Grignard reagents, and cinnamyl acetate is reported. Notably, the enolate from the tandem process provides a much higher level of reactivity and selectivity than the same enolate generated via direct deprotonation, presumably due to differences in the solvation/aggregation state. A novel method for removal of a homoallylic amine protecting group delivers the free amine congeners. The α-allyl group offers a means to generate further valuable α-amino acid structures as exemplified by ring closing metathesis to generate a higher ring homologue of α-aryl-proline.
The Motility of Epididymal or Testicular Spermatozoa Does Not Directly Affect IVF/ICSI Pregnancy Outcomes

ABSTRACT: Our objective was to determine whether the presence of motility in surgically obtained sperm samples improves fertilization and pregnancy rates for patients undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). This was a retrospective study in a hospital-based infertility center. Sixty-seven couples with a diagnosis of azoospermia or severe oligozoospermia who had undergone a sperm retrieval procedure in conjunction with 100 IVF/ICSI cycles from 1995 to 2004 were evaluated. The impact of sperm motility on fertilization and clinical pregnancy rates was determined. The motile and nonmotile sperm groups differed in the number of mature oocytes retrieved (10.7 ± 5.8 vs 13.4 ± 6.0), but fertilization (56.7% vs 59.1%) and embryo cryopreservation rates (35.9% vs 39.3%) were statistically similar. Clinical pregnancy rates did not differ between the motile (38.5%) and nonmotile (31.2%) groups, nor did they differ between obstructive and nonobstructive patients (35.3% vs 26.7%). There was also no statistical difference in pregnancy rates between testicular and epididymal aspiration (35.3% vs 26.7%), although epididymal sperm were significantly more likely to be motile than testicular sperm (100% vs 39.3%, P < .0001). Epididymal aspiration is more likely to produce motile sperm than testicular sperm retrieval. The use of motile sperm from epididymal or testicular samples, however, does not appear to enhance fertilization or clinical pregnancy rates.
Brane dynamics from the Born-Infeld action

Abstract We use the abelian Born-Infeld action for the world-volume gauge field and transverse displacement scalars to explore new aspects of D-brane structure and dynamics. We study several classic gauge field configurations, including point charges in any world-volume dimension and vortices in two world-volume dimensions, and show that, with an appropriate excitation of the transverse coordinate field, they are BPS-saturated solutions. The Coulomb point charge solutions turn out to represent, with considerable fidelity, fundamental strings attached to the brane (their magnetic counterparts describe D1-branes attached to D3-branes). We also show that the S-matrix for small excitations propagating on the point charge solution is consistent with (and gives further illuminating information about) Polchinski's effective open string boundary condition.
Palladium-catalyzed homocoupling of arenediazonium salts: an operationally simple synthesis of symmetrical biaryls

Abstract A simple procedure for the intermolecular homocoupling of arenediazonium salts in air using a catalytic amount of palladium acetate is described. The optimum conditions were found to be 15 mol % palladium acetate in refluxing methanol, with no additional terminal reducing agent required. These optimized conditions were used to prepare biaryls from several arenediazonium tetrafluoroborate salts, and most examples proceeded in moderate to high yields.
Enzymatic end-to-end joining of DNA molecules

Abstract A way to join naturally occurring DNA molecules, independent of their base sequence, is proposed, based upon the presumed ability of the calf thymus enzyme terminal deoxynucleotidyltransferase to add homopolymer blocks to the ends of double-stranded DNA. To test the proposal, covalently closed dimer circles of the DNA of bacteriophage P22 were produced from linear monomers. It is found that P22 DNA as isolated will prime the terminal transferase reaction, but not in a satisfactory manner. Pre-treatment of the DNA with λ exonuclease, however, improves its priming ability. Terminal transferase can then be used to add oligo(dA) blocks to the ends of one population of P22 DNA molecules and oligo(dT) blocks to the ends of a second population, which enables the two DNAs to anneal to one another to form dimer circles. Subsequent treatment with a system of DNA repair enzymes converts the circles to covalently closed molecules at high efficiency. It is demonstrated that the success of the joining system does not depend upon any obvious unique property of the P22 DNA. The joining system yields several classes of by-products, among them closed circular molecules with branches. Their creation can be explained on the basis of the properties of terminal transferase and the DNA repair enzymes.
Gas bubble snap-off under pressure-driven flow in constricted noncircular capillaries

A model for snap-off of a gas thread in a constricted, cornered pore is developed. The time for wetting liquid to accumulate at a pore throat into an unstable collar is examined, as is the time for the resulting pore-spanning lens to be displaced from the pore so that snap-off may repeat. A corner-flow hydrodynamic analysis for the accumulation rate of wetting liquid due to both gradients in interfacial curvature and in applied liquid-phase pressure reveals that wetting-phase pressure gradients significantly increase the frequency of liquid accumulation for snap-off, as compared to liquid rearrangement driven only by differences in pore-wall curvature. For moderate and large pressure gradients, the frequency of accumulation increases linearly with pressure gradient, because of the increased rate of wetting liquid flow along pore corners. Pore topology is important to the theory, because pores with relatively small throats connected to large bodies demonstrate excellent ability to snap off gas threads even when the initial capillary pressure is high or equivalently when the liquid saturation is low. A macroscopic momentum balance across the lens, resulting from snap-off, reveals that lens displacement rates are not linear with the imposed pressure drop. Instead, the frequency of lens displacement scales with powers between 0.5 and 0.6 for pores with dimensionless constriction radii between 0.15 and 0.40. Statistical percolation arguments are employed to form a generation rate expression and connect pore-level foam generation events to macroscopic pressure gradients in porous media. The rate of foam generation by capillary snap-off increases linearly with the liquid-phase pressure gradient and according to a power-law relationship with respect to the imposed gas-phase pressure gradient.
Optimal landing of a helicopter in autorotation

Gliding descent in autorotation is a maneuver used by helicopter pilots in case of engine failure. The landing of a helicopter in autorotation is formulated as a nonlinear optimal control problem. The OH-58A helicopter was used. Helicopter vertical and horizontal velocities, vertical and horizontal displacement, and the rotor angle speed were modeled. An empirical approximation for the induced veloctiy in the vortex-ring state were provided. The cost function of the optimal control problem is a weighted sum of the squared horizontal and vertical components of the helicopter velocity at touchdown. Optimal trajectories are calculated for entry conditions well within the horizontal-vertical restriction curve, with the helicopter initially in hover or forwared flight. The resultant two-point boundary value problem with path equality constraints was successfully solved using the Sequential Gradient Restoration Technique.
Partial oxidation of methane to carbon monoxide and hydrogen over a Ni/Al2O3 catalyst

Abstract Partial oxidation of methane occurs in the temperature range 450–900°C by reaction of an oxygen-deficient CH 4 /O 2 mixture over a 25 wt% Ni/Al 2 O 3 catalyst. Carbon monoxide selectivities approaching 95% and virtually complete conversion of the methane feed can be achieved at temperatures >700°C. The oxidation state and phase composition of the catalyst were characterized using X-ray photoelectron spectroscopy and X-ray powder diffractometry. This study revealed that, under operating conditions, the previously calcined catalyst bed consists of three different regions. The first of these, contacting the initial CH 4 /O 2 /He feed mixture, is NiAl 2 O 4 , which has only moderate activity for complete oxidation of methane to CO 2 and H 2 O. The second region is NiO + Al 2 O 3 , over which complete oxidation of methane to CO 2 occurs, resulting in an exotherm in this section of the bed. As a result of complete consumption of O 2 in the second region, the third portion of the catalyst bed consists of a reduced Ni/Al 2 O 3 phase. Formation of the CO and H 2 products, corresponding to thermodynamic equilibrium at the catalyst bed temperature, occurs in this final region, via reforming reactions of CH 4 with the CO 2 and H 2 O produced during the complete oxidation reaction over the NiO/Al 2 O 3 phase.
Everyday Politics in the Philippines: Class and Status Relations in a Central Luzon Village

Chapter 1 Introduction Chapter 2 Capitalism and Rebellion Entwined Chapter 3 Status and Class Chapter 4 Household Views of Class and Status Politics Chapter 5 Class Resistance Chapter 6 Conflict among Status Groups Chapter 7 Networks among People in Different Classes and Statuses Chapter 8 Everyday Politics and Contending Values
The Impact of Technological Change on Older Workers: Evidence from Data on Computer Use

New technologies like computers alter skill requirements. This paper explores two related effects of the spread of computers on older workers, using data from the Current Population Survey and the Health and Retirement Study. One conclusion is that impending retirement, rather than age alone, explains why older workers used computers less than prime-age workers did. A second conclusion is that computer users retired later than non-users. Although this pattern may arise because workers planning later retirement decided to acquire computer skills, the empirical analysis suggests that the causation also went in the other direction, with computer users choosing to delay retirement. It will be important to understand these effects as the baby boom cohort nears retirement, while technologies continue to change rapidly.
Entry into Emergent and Uncertain Product-Markets: The Role of Associative Rhetoric

We analyze how firms use media-associative rhetoric in their decisions to enter emergent and uncertain product-markets. In the context of our study, this type of rhetoric associates the logics of firms' existing markets with the not-yet-legitimated logics of a newly emerging market. Our panel study shows that firms enter such markets faster when the associative rhetoric has higher (versus lower) volume, positive (versus negative) tenor, firms (versus journalists/analysts) as the source of information, and generalizations (versus specific cases) as the focus. We discuss the implications of our findings for institutional theory and market entry.
THE MICROSCOPIC APPROACH TO NUCLEAR MATTER AND NEUTRON STAR MATTER

We review a variety of theoretical and experimental investigations aimed at improving our knowledge of the nuclear matter equation of state. Of particular interest are nuclear matter extreme states in terms of density and/or isospin asymmetry. The equation of state of matter with unequal concentrations of protons and neutrons has numerous applications. These include heavy-ion collisions, the physics of rare, short-lived nuclei and, on a dramatically different scale, the physics of neutron stars. The "common denominator" among these (seemingly) very different systems is the symmetry energy, which plays a crucial role in both the formation of the neutron skin in neutron-rich nuclei and the radius of a neutron star (a system 18 orders of magnitude larger and 55 orders of magnitudes heavier). The details of the density dependence of the symmetry energy are not yet sufficiently constrained. Throughout this article, our emphasis will be on the importance of adopting a microscopic approach to the many-body problem, which we believe to be the one with true predictive power.
A novel and efficient synthesis of cyclic and acyclic 1,5-alkadiynes by selective coupling of Co2(CO)6-complexed propargyl radicals

Abstract Intra- and intermolecular coupling reactions of Co2(CO)6-complexed propargyl radicals have been realized providing cyclic and acyclic 1,5-alkadiynes in moderate yield and moderate to good diastereoselectivity (44–80%).
A national survey of women's attitudes toward oral contraception and other forms of birth control

PIP: A survey of women 18 years of age and older was conducted in 1993 for The American College of Obstetricians and Gynecologists by The Gallup Organization to examine women's opinion about the effectiveness of oral contraceptives and other methods of birth control. Many of the questions asked in the survey were repeated from an earlier Gallup study conducted for the College in 1985. The survey results were based on telephone interviews with a national sample of 995 women, 18 years of age or older, conducted from August 9 through September 21, 1993. None of the birth control methods was thought to be completely effective, though women tended to score oral contraceptives, implants, the intrauterine device, and injections more highly than other methods. The rhythm method, condoms, gels, spermicides, and foams were thought to be less effective. The condom was the only form of birth control thought by 49% of the women surveyed to provide complete (4%) or considerable (45%) protection against sexually transmitted diseases. However, only 6% reported that they currently used condoms. Other methods more likely to be named as providing at least some protection were spermicides/gels/foams (21%), diaphragms (18%), and sponges (13%). A large majority of the women reported that, with the exception of condoms, none of the other birth control methods provided protection against human immunodeficiency virus (HIV). 38% of women believed that condoms provided quite a lot of protection, and an additional 35% thought they provided at least some protection against HIV transmission. 54% of the women surveyed incorrectly believed there are substantial risks with using oral contraceptives, but 36% did not think so. The number of women citing substantial risks had decreased significantly since 1985 (54% vs. 76%). Of these, cancer was most frequently mentioned (29%). 42% of women named some type of benefit from using oral contraceptives other than preventing pregnancy; although an equal proportion (42%) thought there were no health benefits.
Insight into the role of instantons and their zero modes from lattice QCD

Abstract Evidence from lattice QCD calculations is presented showing that instantons and their associated zero modes play a major role in the physics of light hadrons and the propagation of ight quarks in the QCD vacuum.
Elasticity near the vulcanization transition

Signatures of the vulcanization transition--amorphous solidification induced by the random crosslinking of macromolecules--include the random localization of a fraction of the particles and the emergence of a nonzero static shear modulus. A semi-microscopic statistical-mechanical theory is presented of the latter signature that accounts for both thermal fluctuations and quenched disorder. It is found (i) that the shear modulus grows continuously from zero at the transition, and does so with the classical exponent, i.e., with the third power of the excess cross-link density and, quite surprisingly, (ii) that near the transition the external stresses do not spoil the spherical symmetry of the localization clouds of the particles.
Exact Convex Relaxation of Optimal Power Flow in Radial Networks

The optimal power flow (OPF) problem determines a network operating point that minimizes a certain objective such as generation cost or power loss. It is nonconvex. We prove that a global optimum of OPF can be obtained by solving a second-order cone program, under a mild condition after shrinking the OPF feasible set slightly, for radial power networks. The condition can be checked a priori, and holds for the IEEE 13, 34, 37, 123-bus networks and two real-world networks.
Teaching Scientific Computing Through Projects

Traditional numerical methods courses face several difficulties. There is a performance problem for students who need to combine different skills. Students spend so much time mastering the details that they often miss the point as to why there is a need for scientific computing. Using projects drawn from practical situations, and a good high-level package such as MATLAB**, can overcome much of this. The difficulty associated with learning scientific programming is greatly alleviated. This in turn frees time for studying more advanced methods. The need to combine ideas from different areas makes this an ideal candidate for both team-teaching and student teamwork on the projects. In this paper, we discuss the use of this approach in a variety of scientific computing courses at different levels.
Indium-mediated chemoselective deprotection of trichloroethoxycarbonyl and trichloroacetyl groups

Abstract A new, mild, and chemoselective method for the deprotection of trichloroethoxylcarbonyl and trichloroacetyl groups is described.
(S)-3,7-Dimethyl-2-oxo-6-octene-1,3-diol: an aggregation pheromone of the Colorado potato beetle, Leptinotarsa decemlineata (Say)

(S)-3,7-Dimethyl-2-oxo-6-octene-1,3-diol has been identified as a male-produced pheromone from the Colorado potato beetle. Its gross structure was deduced from its mass and NMR spectra plus synthesis from geraniol. The absolute configuration was determined to be (S) by syntheses of both enantiomers from (R)- and (S)-linalool, respectively.
Information content of the non‐linear power spectrum: the effect of beat‐coupling to large scales

We measure the covariance of the non-linear matter power spectrum from N-body simulations using two methods. In the first case, the covariance of power is estimated from the scatter over many random realizations of the density field. In the second, we use a novel technique to measure the covariance matrix from each simulation individually by re-weighting the density field with a carefully chosen set of functions. The two methods agree at linear scales, but unexpectedly they disagree substantially at increasingly non-linear scales. Moreover, the covariance of non-linear power measured using the re-weightings method changes with box size. The numerical results are consistent with an explanation given in a companion paper, which argues that the cause of the discrepancy is beat-coupling, in which products of Fourier modes separated by a small wavevector couple by gravitational growth to the large-scale beat mode between them. We calculate the information content of the non-linear power spectrum (about the amplitude of the initial, linear power spectrum) using both methods and confirm the result of a previous paper, that at translinear scales the power spectrum contains little information over and above that in the linear power spectrum, but that there is a marked increase in information at non-linear scales. We suggest that, in real galaxy surveys, the covariance of power at non-linear scales is likely to be dominated by beat-coupling to the largest scales of the survey and that, as a result, only part of the information potentially available at non-linear scales is actually measurable from real galaxy surveys.
Some universal estimates for reversible Markov chains

We obtain universal estimates on the convergence to equilibrium and the times of coupling for continuous time irreducible reversible finite-state Markov chains, both in the total variation and in the $L^2$ norms. The estimates in total variation norm are obtained using a novel identity relating the convergence to equilibrium of a reversible Markov chain to the increase in the entropy of its one-dimensional distributions. In addition, we propose a universal way of defining the ultrametric partition structure on the state space of such Markov chains. Finally, for chains reversible with respect to the uniform measure, we show how the global convergence to equilibrium can be controlled using the entropy accumulated by the chain.
The replacement principle in economies with indivisible goods

We consider the problem of allocating a list of indivisible goods and some amount of an infinitely divisible good among agents with equal rights on these resources, and investigate the implications of the following requirement on allocation rules: when the preferences of some of the agents change, all agents whose preferences are fixed should (weakly) gain, or they should all (weakly) lose. This condition is an application of a general principle of solidarity discussed in Thomson (1990b) under the name “replacement principle”. We look for selections from the no-envy solution satisfying this property. We show that in the general case, when the number of objects is arbitrary, there is no such selection. However, in the one-object case (a single prize), up to Pareto-indifference, there is only one selection from the no-envy solution satisfying the property. Such a solution always selects an envy-free allocation at which the winner of the prize is indifferent between his bundle and the losers’ common bundle.
Syntheses of the picrotoxane skeleton via the palladium (II) - catalyzed carbacyclization reaction

Abstract The ability of the palladium (+2)-catalyzed intramolecular carbametalation to form quaternary and vicinal quaternary centers in anti-Markovnikov fashion was demonstrated by the syntheses of the picrotoxane skeleton.
Explaining the Variance of Price–Dividend Ratios

The author reports a bound on the variance of price-dividend ratios and a decomposition of their variance into terms that reflect changes in dividend growth and discount rates. The specification is not restrictive. The test statistics do not require construction of ex post present values; instead, they are restrictions on means, variances, and covariances of price-dividend ratios, dividend growth, and discount rates. He considers implications for the mean price-dividend ratio, and he evaluates whether a low mean discount rate can rationalize the mean and variance of price-dividend ratios. The results do not indicate any striking rejections of present-value models. However, the bulk of the variance of price-dividend ratios must be accounted for by changing forecasts of discount rates, and discount rates must possess some unusual characteristics. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Experimental Determination of the Motional Quantum State of a Trapped Atom

We reconstruct the density matrices and Wigner functions for various quantum states of motion of a harmonically bound ${}^{9}{\mathrm{Be}}^{+}$ ion. We apply coherent displacements of different amplitudes and phases to the input state and measure the number state populations. Using novel reconstruction schemes we independently determine both the density matrix in the number state basis and the Wigner function. These reconstructions are sensitive indicators of decoherence in the system.
O VI Observations of the Onset of Convection Zones in Main-Sequence A Stars*

If magnetic activity in outer stellar atmospheres is due to an interplay between rotation and subsurface convection, as is generally presumed, then one would not expect to observe indicators of activity in stars with Teff 8300 K. Any X-ray or ultraviolet line emission from hotter stars must be due either to a different mechanism or to an unresolved, active, binary companion. Due to their poor spatial resolution, X-ray instruments have been especially susceptible to source confusion. At wavelengths longward of Lyα, the near-ultraviolet spectra of stars hotter than this putative dividing line are dominated by the photospheric continuum. We have used the Far-Ultraviolet Spectroscopic Explorer (FUSE) to obtain spectra of the subcoronal O VI emission lines, which lie at a wavelength where the photospheric continuum of the middle and early A stars is relatively weak. We observed 14 stars spanning a range in Teff from 7720 to 10,000 K. Eleven of the 14 stars showed O VI emission lines, including 6 of the 8 targets with Teff > 8300 K. At face value, this suggests that activity does not fall off with increasing temperature. However, the emission lines are narrower than expected from the projected rotational velocities of these rapidly rotating stars, suggesting that the emission could come from unresolved late-type companions. Furthermore, the strength of the O VI emission is consistent with that expected from an unseen active K or M dwarf binary companion, and the high LX/L(O VI) ratios observed indicate that this must be the case. Our results are therefore consistent with earlier studies that have shown a rapid drop-off in activity at the radiative/convective boundary expected at Teff ~ 8300 K, in agreement with conventional stellar structure models.
Numerical simulations of compliant material response to turbulent flow

Homogeneous and internally structured material coatings are studied numerically as candidates for drag and turbulence generated noise reduction on submersible hulls. Dynamic motions of compliant surfaces may conceptually interrupt random turbulent motions, reducing the turbulent interface stresses and absorbing turbulent energy, and consequently reducing the turbulence at the flow/coating interface. Time dependent, noninteractive, two and three dimensional Monte-Carlo turbulent pressure field models, interactive potential flow models, and interactive Navier-Stokes pseudo-spectral methods are used to represent the unsteady flow, while time-explicit finite element methods are applied to represent a variety of homogeneous layered, and internally structured material coatings. Attention is given to development and testing of an efficient but dynamically interactive fluid/solid interface coupling method, for two- or three-dimensional response simulations. The influence of added mass and of depth overburden on the material response in ocean water is discussed. Promising compliant material coatings include sandwiches of soft, homogeneous layers between thin, stiffer elastic materials and internally structured coatings combining streamwise ribs, spanwise voids and elastically deforming intervening stiffeners.
Open-Market Share Repurchase Programs and Bid-Ask Spreads on the NYSE: Implications for Corporate Payout Policy

This study analyzes bid-ask spreads surrounding announcements of open-market share repurchase programs for a sample of 248 announcements of repurchase programs by NYSE firms over the period January 1984 through June 1988. The sample includes 158 announcements of new programs and 90 announcements regarding continuations of already existing programs. Contrary to the theory that spreads increase surrounding the announcement of open-market share repurchase programs, with both univariate and multivariate tests that control for changes in volume, changes in stock price volatility, and changes in the level of stock price, we find no evidence of an increase in spreads surrounding announcements of open-market share repurchase programs.
Ultrasonic propulsion of kidney stones: Preliminary results of human feasibility study

One in 11 Americans has experienced kidney stones, with a 50% average recurrence rate within 5–10 years. Ultrasonic propulsion (UP) offers a potential method to expel small stones or residual fragments before they become a recurrent problem. Reported here are preliminary findings from the first investigational use of UP in humans. The device uses a Verasonics ultrasound engine and Philips HDI C5-2 probe to generate real-time B-mode imaging and targeted “push” pulses on demand. There are three arms of the study: de novo stones, post-lithotripsy fragments, and the preoperative setting. A pain questionnaire is completed prior to and following the study. Movement is classified based on extent. Patients are followed for 90 days. Ten subjects have been treated to date: three de novo, five post-lithotripsy, and two preoperative. None of the subjects reported pain associated with the treatment or a treatment related adverse event, beyond the normal discomfort of passing a stone. At least one stone was moved in all subjects. Three of five post-lithotripsy subjects passed a single or multiple stones within 1–2 weeks following treatment; one subject passed two (1–2 mm) fragments before leaving clinic. In the pre-operative studies we successfully moved 7 – 8 mm stones. In four subjects, UP revealed multiple stone fragments where the clinical image and initial ultrasound examination indicated a single large stone.
1,3-Dipolar cycloaddition of N-benzyl azomethine ylide to C60: Formation of a C60-fused N-benzylpyrrolidine

Abstract C 60 undergoes 1,3-dipolar cycloaddition with the azomethine ylide derived from N -benzyl- N -(methoxymethyl)- N -[(trimethylsilyl)methyl]amine to give a C 60 -fused N -benzylpyrrolidine in 50 % isolated yield.
Telomerase-Independent Lengthening of Yeast Telomeres Occurs by an Abrupt Rad50p-Dependent, Rif-Inhibited Recombinational Process

Type II survivors arise in Saccharomyces cells lacking telomerase by a recombinational pathway that results in very long and heterogeneous length telomeres. Here we show that type II telomeres appeared abruptly in a population of cells with very short telomeres. Once established, these long telomeres progressively shortened. Short telomeres were substrates for rare, one-step lengthening events. The generation of type II survivors was absolutely Rad50p dependent. In a telomerase-proficient cell, the telomere-binding Rif proteins inhibited telomerase lengthening of telomeres. In a telomerase-deficient strain, Rif proteins, especially Rif2p, inhibited type II recombination. These data argue that only short telomeres are substrates for type II recombination and suggest that the donor for this recombination is not a chromosomal telomere.
SETI searches for radio transients from Kepler Field planets and Astropulse candidates

We present a search for fast radio transients in targeted observations of planet candidates in the Kepler Field and candidate Astropulse sources.
Quenching of combustion by shear flows

We consider a model describing premixed combustion in the presence of fluid flow: a reaction-diffusion equation with passive advection and ignition-type nonlinearity. What kinds of velocity profiles are capable of quenching (suppressing) any given flame, provided the velocity's amplitude is adequately large? Even for shear flows, the solution turns out to be surprisingly subtle. In this article we provide a sharp characterization of quenching for shear flows; the flow can quench any initial data if and only if the velocity profile does not have an interval larger than a certain critical size where it is identically constant. The efficiency of quenching depends strongly on the geometry and scaling of the flow. We discuss the cases of slowly and quickly varying flows, proving rigorously scaling laws that have been observed earlier in numerical experiments. The results require new estimates on the behavior of the solutions to the advection-enhanced diffusion equation (also known as passive scalar in physical literature), a classical model describing a wealth of phenomena in nature. The technique involves probabilistic and partial-differential-equation (PDE) estimates, in particular, applications of Malliavin calculus and the central limit theorem for martingales
QCD EVOLUTION WORKSHOP: INTRODUCTION

The introduction talk given at the beginning of QCD Evolution workshop held in Thomas Jefferson National Accelerator Facility (Jefferson Lab) on May 14 -17, 2012.
Performance persistence of closed-end funds

Studies of performance persistence of closed-end funds (CEFs) use two measures of persistence; autocorrelation and rank correlation of performance. The autocorrelation measure offers limited information because it cannot separate persistence relative to the market and to the industry. The rank correlation measure is generally applied to two periods, disregarding multi-period persistence. We investigate performance persistence of CEFs in terms of both market price return and net asset value return using contingency tables and multiple regression models. Jensen’s alpha and the Sharpe ratio are used as measures of risk-adjusted performance. We test three hypotheses: (i) CEFs performing better than the industry median will do so persistently, (ii) CEFs outperform the market persistently; and (iii) performance persistence can be partly explained by dividend yield. The findings are fivefold. First, the number of persistent years varies with the models used to calculate risk-adjusted performance. Second, with 4-index unconditional beta fixed variance model, CEFs persistently beat their industry for six out of 10 years in terms of both market price return and net asset value return. Third, with a 4-index unconditional beta fixed variance model, we find performance persistence relative to market for 6 and 7 years, out of the 10 years considered, in terms of market price return and net asset value return, respectively. Fourth, the disaggregate sample tests show that performance of municipal bond funds is more persistent than equity funds and taxable bond funds. Fifth, dividend patterns can partially explain persistence with liquidity as control.