cssi/SciSciGPT-SciSciNet huggingface dataset:
X-RAY EMISSION FROM YOUNG STARS IN THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

We present a 40 ks Chandra observation of the IRAS 20126+4104 core region. In the inner 6'' two X-ray sources were detected, which are coincident with the radio jet source I20S and the variable radio source I20Var. No X-ray emission was detected from the nearby massive protostar I20N. The spectra of both detected sources are hard and highly absorbed, with no emission below 3 keV. For I20S, the measured 0.5-8 keV count rate was 4.3 counts ks–1. The X-ray spectrum was fitted with an absorbed 1T APEC model with an energy of kT =10 keV and an absorbing column of N H = 1.2 × 1023 cm–2. An unabsorbed X-ray luminosity of about 1.4 × 1032 erg s–1 was estimated. The spectrum shows broad line emission between 6.4 and 6.7 keV, indicative of emission from both neutral and highly ionized iron. The X-ray light curve indicates that I20S is marginally variable; however, no flare emission was observed. The variable radio source I20Var was detected with a count rate of 0.9 counts ks–1 but there was no evidence of X-ray variability. The best-fit spectral model is a 1T APEC model with an absorbing hydrogen column of N H = 1.1 × 1023 cm–2 and a plasma energy of kT = 6.0 keV. The unabsorbed X-ray luminosity is about 3 × 1031 erg s–1.
NNLL threshold resummation for top-pair and single-top production

I discuss threshold resummation at NNLL accuracy in the standard moment-space approach in perturbative QCD for top-pair and single-top production. For top quark pair production I present new approximate NNLO results for the total cross section and for the top quark transverse momentum and rapidity distributions at 8 TeV LHC energy. I discuss the accuracy of the soft-gluon approximation and show that the NLO and NNLO approximate results from resummation are practically indistinguishable from exact NLO and partial NNLO results. For single top production I present new approximate NNLO results for the total cross sections in all three channels at the LHC and also for the top quark transverse momentum distributions in t-channel production and in top-quark associated production with a W boson. For both $$t\bar t$$ and single-top production the agreement of theoretical results with LHC and Tevatron data is excellent.
On Even Triangulations of 2-Connected Embedded Graphs

Recently, Hoffmann and Kriegel proved an important combinatorial theorem [SIAM J. Discrete Math., 9 (1996), pp. 210--224]: Every 2-connected bipartite plane multigraph G without 2-cycle faces has a triangulation in which all vertices have even degree (this is called an even triangulation). Combined with the classical Whitney's theorem, this result implies that every such graph has a 3-colorable plane triangulation. Using this theorem, Hoffmann and Kriegel significantly improved the upper bounds of several art gallery and prison guard problems. A complicated O(n2) time algorithm was obtained in [SIAM J. Discrete Math., 9 (1996), pp. 210--224] for constructing an even triangulation of G. Hoffmann and Kriegel conjectured that there is an O(n3/2) time algorithm for solving this problem. In this paper, we develop a simple proof of the above theorem. Our proof reveals and relies on a natural correspondence between even triangulations of G and certain orientations of G. Based on this new proof, we obtain a very simple O(n) time algorithm for finding an even triangulation of G. We also extend our proof to show the existence of even triangulations for similar graphs on high genus surface.
Raman spectral shifts relevant to electron delocalization in polydiacetylenes

The extent of π electron delocalization in solid‐state polymerized diacetylenes is derived from observed Raman vibrational frequencies. Raman intense C=C and C≡C vibrations indicate that the polymer backbone is best represented by (=C–C≡C–C=)n. However, vC=C is linearly correlated with vC≡C over a wide frequency range and both frequencies increase with decreasing phase perfection. This suggests a significant fractional contribution δ from the mesomeric structure (–C=C=C=C–)n, which decreases the π bond order of C=C to 1‐δ and C≡C to 2‐δ. Both vC=C and vC≡C are calculated as a function of δ and compared with observed frequencies for variously substituted polydiacetylenes in different physical states. Resulting ΔvC=C/ΔvC≡C values obtained using two different bond‐length to bond‐order approximations are in good agreement with the observed value (1.19±0.12).
Equivalent Forms of the Bessis–Moussa–Villani Conjecture

The BMV conjecture for traces, which states that \({\text{Tr}}\;{\text{exp}}\left( {A - \lambda B} \right)\) is the Laplace transform of a positive measure, is shown to be equivalent to two other statements: (i) The polynomial \(\lambda \mapsto {\text{Tr}}\;\left( {A + \lambda B} \right)^p\) has only non-negative coefficients for all \(A,B \geqslant 0,p \in \mathbb{N}\) and (ii) \(\lambda \mapsto {\text{Tr}}\;\left( {A + \lambda B} \right)^{ - p}\) is the Laplace transform of a positive measure for \(A,B \geqslant 0,p > 0\).
A categorification for the chromatic polynomial

For each graph we construct graded cohomology groups whose graded Euler characteristic is the chromatic polynomial of the graph. We show the cohomology groups satisfy a long exact sequence which corre- sponds to the well-known deletion-contraction rule. This work is motivated by Khovanov's work on categorification of the Jones polynomial of knots. AMS Classification 57M27; 05C15
The search for cavitation in vivo

Until the mid 1970s, it was generally assumed that, with the short pulses of ultrasound (US) used in medical diagnosis, there was little need for concern about the possibility of inertial cavitation in vivo. This assumption came into question when experimental evidence indicated that killing of fruit fly larvae by diagnostically relevant US was associated with the presence of gas in the respiratory apparatus of the organisms. Independent theoretical contributions by Flynn and Apfel in the early 1980s made it clear that complacency in regard to cavitation was not warranted. Later, the mammalian lung, as with larva, was shown to be particularly vulnerable when it contained air. Yet, overall evidence suggests that lung hemorrhage is not consistent with the classical picture of inertial cavitation. Most recently, however, hemolysis and hemorrhage associated with the use of contrast agents have provided nearly incontrovertible evidence of the occurrence of cavitation in vivo.
Mercury emission to the atmosphere from experimental manipulation of DOC and UVR in mesoscale field chambers in a freshwater lake.

Mesocosm experiments in an optically transparent lake allow the manipulation of both dissolved organic carbon (DOC) and incident ultraviolet radiation (UVR) in order to study mercury reduction and emission processes. In the absence of UVR and the presence of visible light, mercury emission is very low (∼0.3 ng/m2/h). When UVR is permitted in the mesocosm chambers, mercury emission increases, with emission rates ranging from 0.3 to 2.5 ng/m2/h. At concentrations between 1.5 and 2.5 mg/L DOC, mercury emission does not appear to depend on either the concentration or the optical properties of the DOC. In particular, the addition of 1.0 mg/L DOC from a nearby wetland to a photobleached mesocosm did not increase the emission of mercury. The similarities between mercury emission from highly photobleached 1.5 mg/L DOC and from terrestrially enriched 2.5 mg/L DOC suggest that the moieties responsible for mercury reduction are far in excess of that needed for mercury reduction. Using the measured flux rate of mercu...
Analytical and Finite Element Modeling of Riveted Lap Joints in Aircraft Structure

Modeling procedures for the stress analysis of riveted lap joints in aircraft structure are proposed in this paper using both analytical and numerical methods. In the analytical method, a complex variational approach is employed to determine the stresses in joined plates containing single or multiple loaded holes. The effects of finite geometry are taken into account by the variational formulations. An iterative scheme is carried out to handle the deformation compatibility between all joined members, hi the numerical method, finite element analyses are conducted using the commercial packages MSC/Patran and MSC/Nastran. Gap elements are used to simulate the rivet-hole interactions. Both linear and nonlinear deformations are considered. The two modeling procedures are complementary to each other. While the analytical method is efficient for parametric studies, the numerical method is capable of dealing with relatively more complicated geometry and loading conditions. Results of several example problems are presented and reasonably good agreement between the two modeling procedures is demonstrated.
Preparation of Substituted Piperazinones via Tandem Reductive Amination−(N,N‘-Acyl Transfer)−Cyclization

A one-pot, tandem reductive amination−transamidation−cyclization reaction was employed to produce substituted piperazin-2-ones in good yields. Various amino acid methyl esters and transferable acyl groups were examined to establish the reaction's scope.
Modeling violation of Hawaii's crosswalk law

In 2005, Hawaii strengthened its pedestrian crosswalk laws. Previously, motorists had the option yielding or slowing down at a crosswalk and had to stop "only when necessary." The new law requires drivers to stop and yield to pedestrians at crosswalks. The purpose of this study is to examine patterns of violation and compliance with the law among both pedestrians and drivers. Observational studies at crosswalks were done in the Spring of 2006. In addition to reporting on overall rates of compliance, the characteristics of both pedestrians and drivers who either violate or comply with the law are described. While pedestrian compliance is higher than that of drivers, there are interesting differences to report in terms of age, gender, type of intersection, land use, and other factors. In addition to the results of a descriptive analysis, logistic regression models predicting the likelihood of violation of the crosswalk laws by either pedestrians or drivers, as a function of their characteristics, the type of intersection, and other factors are presented. The study finds that drivers tend to commit proportionately more violations than pedestrians, and violations are committed by a broader range of drivers than pedestrians. These results suggest that education and enforcement should be directed towards drivers. Future directions for research and enhancing the safety of pedestrians are described in a concluding section.
Logical relevance: problems with the reference population and DNA mixtures in People v. Pizarro

The concept of relevance is fundamental to the law of evidence. A California court of appeals recently invoked this concept to deem inadmissible estimates of the relative frequency of an incriminating DNA type in major racial groups and computations relating to a mixture of DNA from more than one person. This article shows that these statistics are relevant evidence because they help the factfinder assess the significance of matching DNA types under various hypotheses that might be entertained about the origin of the DNA samples.
Multiferroic Behavior in Trimerized Mott Insulators

We demonstrate multiferroic behavior in trimerized Mott insulators through the interplay between spins and electric dipole moments resulting from electronic charge fluctuations in frustrated units. The model consists of stacked triangular layers of trimers with small intertrimer exchange interactions ${J}^{\ensuremath{'}}$ and ${J}^{\ensuremath{'}\ensuremath{'}}$. Ferroelectric states coexist with ferro- or antiferromagnetic orderings depending on the value of the magnetic field $H$ and the sign of the interlayer exchange ${J}^{\ensuremath{'}\ensuremath{'}}$. The electric polarization undergoes abrupt changes as a function of $H$.
Living on the edge: cosmology on the boundary of anti-de Sitter space

Abstract We sketch a particularly simple and compelling version of D-brane cosmology. Inspired by the semi-phenomenological Randall–Sundrum models, and their cosmological generalizations, we develop a variant that contains a single (3+1)-dimensional D-brane which is located on the boundary of a single bulk (4+1)-dimensional region. The D-brane boundary is itself to be interpreted as our visible universe, with ordinary matter (planets, stars, galaxies) being trapped on this D-brane by string theory effects. The (4+1)-dimensional bulk is, in its simplest implementation, adS 4+1 , anti-de Sitter space. We demonstrate that a k =+1 closed FLRW universe is the most natural option, though the scale factor could quite easily be so large as to make it operationally indistinguishable from a k =0 spatially flat universe. (With minor loss of elegance, spatially flat and hyperbolic FLRW cosmologies can also be accommodated.) We demonstrate how this model can be made consistent with standard cosmology, and suggest some possible observational tests.
Economic Efficiency and Damage Awards in Personal Injury Torts

Past discussions about economic efficiency and personal injury torts have focused on the relationship between the optimal amount of care a potential injurer should take for economic efficiency. Typically this discussion has assumed that the economic damages are strictly monetary without any full consideration of how these damages should be measured. This paper constructs a general model which incorporates as an unknown the amount of monetary damages that an injurer should pay in the interest of economic efficiency. The optimal amount of damages need to be known to serve as signal for the amount of care a potential injurer should take. The model shows that the optimal damage award should be at that point where that marginal utility of money paid out by the injurer equals the marginal utility of the money received by the victim under his utility function after the accident and not considering any non-monetary damages.
Crystal Structure of an Ammonium Nickel Molybdate Prepared by Chemical Precipitation.

A layered ammonium nickel molybdate was prepared by precipitation from a solution of nickel nitrate and ammonium heptamolybdate. The compound obtained, (NH(4))HNi(2)(OH)(2)(MoO(4))(2), is trigonal with hexagonal unit cell parameters a = 6.0147(4) A, c = 21.8812(13) A, and Z = 3. A powder X-ray diffraction pattern was obtained using synchrotron radiation. The structure was generated from three-dimensional Patterson and difference Fourier density maps and refined in the space group Rtm by the Rietveld method. The structure consists of molybdate tetrahedra and nickel octahedra forming layers perpendicular to the c axis. There are three layers per unit cell, with ammonium ions incorporated between the layers. The structure is a member of a solid solution series of (NH(4))H(2)(x)()Ni(3)(-)(x)()O(OH)(MoO(4))(2), where 0 </= x </= (3)/(2). The nonstoichiometry arises from variable occupancy of the nickel position and allows for the formation of these compounds having Ni/Mo ratios varying from 0.75 to 1.5.
Boundary conditions in supergravity on a manifold with boundary

We explain why it is necessary to use boundary conditions in the proof of supersymmetry of a supergravity action on a manifold with boundary. Working in both boundary (``downstairs'') and orbifold (``upstairs'') pictures, we present a bulk-plus-boundary/brane action for the five-dimensional (on-shell) supergravity which is supersymmetric with the use of fewer boundary conditions than were previously employed. The required Gibbons-Hawking-like Y-term and many other aspects of the boundary/orbifold picture correspondence are discussed.
Revised Structures of N-Substituted Dibrominated Pyrrole Derivatives and Their Polymeric Products. Termaleimide Models with Low Optical Band Gaps.

This paper describes an unexpected rearrangement/oxidation of N-substituted 2,5-dibromopyrroles upon treatment with HNO3. The bromides migrate from the 2,5-positions to the 3,4-positions with subsequent oxidation at the 2,5-positions to afford N-substituted 3,4-dibromomaleimides; the structure was confirmed by single-crystal X-ray analysis. The maleimides were then polymerized to the poly(N-substituted-3,4-maleimide)s with copper bronze. This constitutes a revision of structure for the monomers and polymers. The propensity for the dibromide migration was further confirmed by treatment of N-benzyl-2,5-dibromopyrrole under nonoxidative acidic conditions (p-TsOH) to afford N-benzyl-3,4-dibromopyrrole; both the starting material and product structures were confirmed by single-crystal X-ray analysis. Several termaleimides were prepared from pyrrole, maleic anhydride, and citraconic anhydride. These trimeric compounds underwent enormous shifts in their optical absorbance maxima (ca. 200 nm) when bases or nucleo...
Diagnostic studies in a Hall accelerator at low exhaust pressure.

Effect of mass entrainment from vacuum tank and electrode erosion on plasma velocity determined from mass flow and thrust of Hall accelerator
THE IMPACT OF CHANGING MARKETS AND COMPETITION ON THE NPD SPEED/MARKET SUCCESS RELATIONSHIP

Our research examines the relationships among four factors thought to be important to new product developing organizations. Those factors include the speed with which product developers produce new products and bring them to market; the degree of integration among the various groups participating in the New Product Development (NPD) process; the proficiency with which the product developers perform their tasks; and the degree of success attained upon the completion of the NPD process. Market dynamism, or the degree of customer changeability, and market hostility, or the degree of market competitiveness, are thought to moderate the relationships among the four previously noted factors. The research questions driving our investigation include: (1) Does NPD project success vary with NPD process speed?; (2) Does NPD speed vary across innovation types (new-to-the-world products, line extensions, etc.)?; (3) Does the strength of the relationships among NPD speed, organizational integration, NPD proficiency (overall and Fuzzy Front End [FFE]), and success vary with the degree of environmental dynamism (changing customer needs)?; and (4) Does the strength of the relationships among NPD speed, organizational integration, NPD proficiency (overall and FFE), and success vary with the degree of market hostility (competition)? We probed the electrical equipment, medical device, and heavy construction equipment industries to provide the data to address our research questions. Our research suggests that the speed with which projects were completed in our sample did not vary between projects that were more or less successful. We also found that the speed with which projects were completed did not vary across various product categories (new-to-the-world, line extensions, etc.) of newly developed products for the industries studied. Primarily, we found that market dynamism moderates the relationship between NPD speed and NPD proficiency whereas environmental hostility mediates NPD speed and NPD proficiency, NPD speed and organizational integration, and NPD speed and new product market success. Our data indicate that speed is not associated with NPD proficiency, degree of organizational integration, and new product success in less dynamic markets whereas speed has an inverse relationship with successfully entering new markets, the proficiency with which development and launch activities are performed, and the proficiency with which new product marketing strategies were implemented in more dynamic markets. Finally, we found that speed is inversely related to successfully entering new markets, overall NPD proficiency and organizational integration, predevelopment stage proficiency and organizational integration, and development and launch proficiency and organizational integration in non-hostile (competitive) environments whereas we found no significant relationships between these factors and speed in hostile environments. We provide several implications for both scholars and NPD managers.
Spatial numerical simulation of boundary layer transition: effects of a spherical particle

In the present study, the effects of an isolated stationary spherical particle on the transition process in a flat-plate boundary layer are examined by a spatial direct numerical simulation. The full three-dimensional time-dependent incompressible Navier–Stokes equations are integrated by a time-splitting method and discretized spatially by a high-order finite difference/spectral method. A virtual boundary technique defining the no-slip boundary of a sphere is implemented within the Cartesian geometry of the computational grid. Two numerical simulations which consider the effects of the sphere on the boundary layer are presented. The subcritical Reynolds number case reveals the appearance of hairpin vortices shed into the sphere wake which decay as they are convected downstream. The initial interaction of the sphere and the boundary layer produces a three-dimensional isolated disturbance comprising a wave part and a transient part. The decaying transient part is convected downstream at the local mean velocity, while the wave part induces a decaying Tollmien–Schlichting wave in the flow field. In the second case, an increase in the Reynolds number results in a wedge of incipient turbulent flow downstream of the sphere. The development of the wake of the sphere is dominated by the appearance of an isolated disturbance which rapidly breaks down forming a structure resembling a turbulent spot. It is demonstrated that the transition induced by a sphere in the boundary layer is due to a mechanism related to bypass transition.
On the method of matched asymptotic expansions

The present evaluation of the method of asymptotic expansions (MAE) indicates that the various terms of the common solution of MAE can be generated as polynomials in stretched variables, without actually solving them from the outer solution, as is currently the practice. It is also noted that the common solution of the MAE and the intermediate solution of the singular-perturbation method are the same; these methods therefore yield identical results for a certain class of problems. Two illustrative problems are treated.
Macroeconomic interdependence under incomplete markets

This paper uses a two-country, flexible-price model with overlapping generations of infinitely lived households to study the role of net foreign asset dynamics in the propagation of productivity shocks. Absence of Ricardian equivalence ensures existence of a unique steady-state level of net foreign assets, to which the economy returns following temporary shocks. Model dynamics are significantly different from those of a setup in which terms of trade movements perform all the international adjustment and net foreign assets do not move. The difference relative to a complete markets economy in which net foreign asset movements play no role in shock transmission is smaller. It is amplified if the substitutability across goods rises and if shocks are permanent.
A method of probing the torus geometry

Abstract I propose a method of inferring the geometry of the obscuring material in radio-loud active galaxies by examining the relationship between the inferred nuclear extinction and the core-to-lobe radio flux ratio. I use Monte Carlo simulations to estimate the quality of data expected from such a project and examine its usefulness in discriminating between alternative structures.
N + N → N2 Reaction Rates on Rh(111)

The authors have studied the reaction of N atoms adsorbed on Rh(111) to make gas phase N[sub 2], using a combination of temperature programmed desorption and kinetic modeling. Electron beam dissociation of adsorbed NO was used to prepare surfaces with the highest N atom coverages ([approx]0.5 monolayer) yet reported. Surfaces with coadsorbed N and O were also studied. These experiments and modeling show that N atoms desorb as N[sub 2] from Rh(111) in at least three distinct desorption states with reaction rates that vary by about four orders of magnitude. Comparison of the N[sub 2] formation rates reported here with those measured during reaction of CO and NO at 16 Torr shows that under reaction conditions the surface most likely has an intermediate coverage of nitrogen atoms. In addition, the author's results show that at high N atom coverages N[sub 2] is formed at least 50 x faster than under reaction conditions, indicating that N atom recombination is not the rate limiting step in the reduction of NO by CO over Rh(111). 17 refs., 6 figs., 1 tab.
Bid-ask spreads and the avoidance of odd-eighth quotes on Nasdaq: An examination of exchange listings

This paper examines 472 securities that were listed on Nasdaq and moved to the NYSE or Amex. When Nasdaq market makers avoid odd-eighth quotes, bid-ask spreads are large and decline dramatically with exchange listing. When market makers use both odd and even eighths, spreads are smaller and decline only slightly with exchange listing. The large spreads observed when Nasdaq market makers avoid odd-eighths cannot be explained by security-specific characteristics. Instead, the results support the conclusion that the avoidance of odd-eighth quotes is used as a coordination device among Nasdaq market makers to maintain supra-competitive bid-ask spreads.
Fully ionized quasi-one dimensional magnetic nozzle flow

Fully ionized quasi-one dimensional magnetic nozzle flow analysis, including effects of unequal electron and ion temperatures and electron thermal conductivity
Technology Status of a Fluorine-Hydrazine Propulsion System for Planetary Spacecraft

The basic technology exists and a system integration program is well underway to allow incorporation of a fluorine-hydrazine propulsion system into future spacecraft required for unmanned planetary missions. These spacecraft would be inserted in earth orbit using the Space Transportation System Shuttle and given its initial sendoff by the Inertial Upper Stage (IUS). The design of a typical propulsion system, assessment of thermal and structural impacts on a selected spacecraft and comparative studies with conventional propulsion systems have been completed. A major part of the current JPL Program involves assembly of a 3650 N thrust demonstration system using titanium tanks, flight weight components and structure. This system will be used to demonstrate the state-of-the-art throughout a representative flight system's qualification.
Faster Swap Edge Computation in Minimum Diameter Spanning Trees

In network communication systems, frequently messages are routed along a minimum diameter spanning tree (MDST) of the network, to minimize the maximum travel time of messages. When a transient failure disables an edge of the MDST, the network is disconnected, and a temporary replacement edge must be chosen, which should ideally minimize the diameter of the new spanning tree. Such a replacement edge is called a best swap. Preparing for the failure of any edge of the MDST, the all-best-swaps (ABS) problem asks for finding the best swap for every edge of the MDST. Given a 2-edge-connected weighted graph G=(V,E), where |V|=n and |E|=m, we solve the ABS problem in O(mlog n) time and O(m) space, thus considerably improving upon the decade-old previously best solution, which requires $O(n\sqrt{m})$ time and O(m) space, for m=o(n 2/log 2 n).
Effect of regenerative process on the sample stability of a multiple delay differential equation

Abstract In this paper, explicit analytical expressions for the stability behaviour of a single degree of freedom machining model have been derived. The regenerative chatter due to chip thickness and feed rate variations, a delay in the spring force and the probabilistic property of the displacement process of the chatter induced by the earlier tool cuts in the undeformed chip thickness have been taken into account. A characteristic equation for the linearized stability at equilibrium machining is presented, and regions of stable and unstable machining for multiple fixed time delays are captured in the phase plane of two model parameters. By a combined use of the classical Hopf bifurcation theorem and the centre manifold, equations governing stochastic chattering, which are infinite in character, are reduced to two-dimensional ordinary differential equations. The integral averaging method and the Lyapunov exponent have been employed to explicitly derive the required analytical expressions.
Injection of Radioactivities into the Forming Solar System

Meteorite studies have revealed the presence of short-lived radioactivities in the early solar system. The current data suggest that the origin of at least some of the radioactivities requires contribution from recent nucleosynthesis at a stellar site. This sets a strict time limit on the time available for the formation of the solar system and argues for the theory of the triggered origin of the solar system. According to this scenario, the formation of our planetary system was initiated by the impact of an interstellar shock wave on a molecular cloud core. The shock wave originated from a nearby explosive stellar event and carried with it radioactivities produced in the stellar source. In addition to triggering the collapse of the molecular cloud core, the shock wave also deposited some of the freshly synthesized radioactivities into the collapsing system. The radioactivities were then incorporated into the first solar system solids, in this manner leaving a record of the event in the meteoritic material. The viability of the scenario can be investigated through numerical simulations studying the processes involved in mixing shock-wave material into the collapsing system. The high-resolution calculations presented here show that injection occurs through Rayleigh-Taylor instabilities, the injection efficiency is approximately 10%, and temporal and spatial heterogeneities in the abundances of the radioactivities may have existed at the time of their arrival in the forming solar system.
A regiospecific method for the hydrocyanation of olefins

Abstract A convenient method for the anti-Markovnikov hydrocyanation of olefins utilizing organozirconium chemistry has been developed. This method has been shown to tolerate a wide range of functionality in the substrate olefin.
Hotspots, Basalts, and the Evolution of the Mantle

The trace element concentration patterns of continental and ocean island basalts and of mid-ocean ridge basalts are complementary. The relative sizes of the source regions for these fundamentally different basalt types can be estimated from the trace element enrichment-depletion patterns. Their combined volume occupies most of the mantle above the 670 kilometer discontinuity. The source regions separated as a result of early mantle differentiation and crystal fractionation from the resulting melt. The mid-ocean ridge basalts source evolved from an eclogite cumulate that lost its late-stage enriched fluids at various times to the shallower mantle and continental crust. The mid-ocean ridge basalts source is rich in garnet and clinopyroxene, whereas the continental and ocean island basalt source is a garnet peridotite that has experienced secondary enrichment. These relationships are consistent with the evolution of a terrestrial magma ocean.
BC-type interpolation Macdonald polynomials and binomial formula for Koornwinder polynomials

We consider 3-parametric polynomialsP μ * (x; q, t, s) which replace theA n-series interpolation Macdonald polynomialsP μ * (x; q, t) for theBC n-type root system. For these polynomials we prove an integral representation, a combinatorial formula, Pieri rules, Cauchy identity, and we also show that they do not satisfy any rationalq-difference equation. Ass → ∞ the polynomialsP μ * (x; q, t, s) becomeP μ * (x; q, t). We also prove a binomial formula for 6-parametric Koornwinder polynomials.
Catalytic Asymmetric Synthesis of Piperidine Derivatives through the [4 + 2] Annulation of Imines with Allenes

Although tertiary phosphines have emerged as remarkably versatile nucleophilic catalysts, there has been only very limited progress in achieving asymmetric catalysis with chiral phosphines. In this report, the first highly enantioselective variant of the Kwon annulation of imines with allenes is described. Thus, C2-symmetric chiral phosphepine 1 serves as an effective catalyst for this powerful process, furnishing an array of functionalized piperidine derivatives with very good stereoselectivity.
Automatic mediation in group problem solving

Conflicts over allocation of speaking time often occur in both formal and informal conferencing. In a problem solving experiment, an automatic mediator resolved conflicting requests during telephone conferencing. It combined inputs signaling intention to speak, using preprogrammed rules that then selected the new speaker. Teams of four undergraduate students repeatedly called upon the mechanism to resolve conflicting requests. Participant and mechanism behavior were recorded for later evaluation by a protocol analysis program that checked data strings for correct syntax, simulated behavior of alternative resolution rules, and aggregated group and individual data for processing with a statistical package. This approach to group experimentation yields significant methodological advantages in terms of verification of correct experiment administration, reduction in experimenter effects, and promotion of self-direction by participants.
Signatures of Galaxy-Cluster Interactions: Tully-Fisher Observations at z~0.1

We have obtained new optical imaging and spectroscopic observations of 78 galaxies in the fields of the rich clusters Abell 1413 (z = 0.14), Abell 2218 (z = 0.18), and Abell 2670 (z = 0.08). We have detected line emission from 25 cluster galaxies plus an additional six galaxies in the foreground and background, a much lower success rate than what was found (65%) for a sample of 52 lower richness Abell clusters in the range 0.02 z 0.08. We have combined these data with our previous observations of Abell 2029 and Abell 2295 (both at z = 0.08), which yields a sample of 156 galaxies. We evaluate several parameters as a function of cluster environment: Tully-Fisher residuals, Hα equivalent width, and rotation curve asymmetry, shape, and extent. Although Hα is more easily detectable in galaxies that are located further from the cluster cores, we fail to detect a correlation between Hα extent and galaxy location in those where it is detected, again in contrast with what is found in the clusters of lesser richness. We fail to detect any statistically significant trends for the other parameters in this study. The zero point in the z ~ 0.1 Tully-Fisher relation is marginally fainter (by 1.5 σ) than that found in nearby clusters, but the scatter is essentially unchanged.
A mechanistic model for radiation-induced crystallization and amorphization in U3Si

Abstract Of concern for the proposed Advanced Neutron Source and Research Reactors, which would use intermetallic fuels, are potential radiation-induced phenomena that could affect the physical and mechanical properties of intermetallic aluminum dispersion fuels. For this reason and because of observations of radiation-induced amorphization of U3Si during ion irradiation, the phenomenology of radiation-induced amorphization is assessed. A rate theory model is formulated wherein amorphous clusters are formed by the damage event. These clusters are considered centers of expansion (CE), or excess-free-volume zones. Simultaneously, centers of compression (CC) are created in the material. In general, many more CCs are created per ion than CEs. The CCs are local regions of increased density that travel through the material as an elastic (e.g., acoustic) shock wave. The CEs can be annihilated upon contact with a sufficient number of CCs, forming either a crystallized region indistinguishable from the host material, or a region with a slight disorientation (recrystallized grain). Recrystallized grains grow by the accumulation of additional CCs. Full amorphization is calculated on the basis of achieving a volume fraction consistent with the close packing of spherical entities. Amorphization of a recrystallized grain is hindered by the presence of the grain boundary. Preirradiation of U3Si above the critical temperature for amorphization results in the observed formation of nanometer-size grains. In addition, the subsequent reirradiation of these samples in the same ion flux at temperatures below the critical temperatures shows that the material has developed a resistance to radiation-induced amorphization (i.e., a higher dose is needed to amorphize the preirradiated samples than for those that have not been preirradiated). In the model, it is assumed that grain boundaries act as effective defect sinks, and that enhanced defect annihilation is responsible for retarding amorphization below the critical temperature. The calculations have been validated against data from ion-irradiation experiments with U3Si. The model has also been applied to the ion-induced motion of the interface between crystalline and amorphous phases of U3Si. The results of this analysis are compared to data and results of calculations for ion bombardment of Si.
Direct Transition-Metal-Free Intramolecular Arylation of Phenols

Direct transition-metal-free, base-mediated intramolecular arylation of phenols with aryl halides has been developed. In the presence of 2.5 equiv of t-BuOK in dioxane at 140 °C, the intramolecular cyclization of 3-(2-halobenzyloxy)phenols affords 6H-benzo[c]chromenes in high yields. This reaction proceeds by an initial formation of a benzyne intermediate followed by an aromatic sp2 C−H functionalization (a formal C−H activation) to form the carbon−carbon bond.
A cope rearrangement-based route to hexahydroazulenes.

2-exo-Vinyl-7-alkylidenenorbornanes, readily prepared from fulvene Diels−Alder adducts, undergo smooth Cope rearrangement at elevated temperatures to produce hexahydroazulene derivatives.
Time-domain optical sensing

A chirped optical supercontinuum is used to map absorption spectra into temporal waveforms. Time-domain spectral measurement of acetylene is demonstrated using a modelocked fibre laser as the source of broadband radiation and a sampling oscilloscope for spectral measurement.
Amyloid Formation in Heterogeneous Environments: Islet Amyloid Polypeptide Glycosaminoglycan Interactions

Amyloid formation plays an important role in a broad range of diseases, and the search for amyloid inhibitors is an active area of research. Amyloid formation takes places in a heterogeneous environment in vivo with the potential for interactions with membranes and with components of the extracellular matrix. Naturally occurring amyloid deposits are associated with sulfated proteoglycans and other factors. However, the vast majority of in vitro assays of amyloid formation and amyloid inhibition are conducted in homogeneous solution where the potential for interactions with membranes or sulfated proteoglycans is lacking and it is possible that different results may be obtained in heterogeneous environments. We show that variants of islet amyloid polypeptide (IAPP), which are non-amyloidogenic in homogeneous solution, can be readily induced to form amyloid in the presence of glycosaminoglycans (GAGs). GAGs are found to be more effective than anionic lipid vesicles at inducing amyloid formation on a per-charge basis. Several known inhibitors of IAPP amyloid formation are shown to be less effective in the presence of GAGs.
Dynamic control of session input rates in communication networks

We consider a distributed iterative algorithm for dynamically adjusting the input rate of each session of a voice or data network using virtual circuits so as to exercise flow control. Each session origin periodically receives information regarding the level of congestion along the session path and iteratively corrects its input rate. In this paper we place emphasis on voice networks, but the ideas involved are also relevant for dynamic flow control in data networks. The algorithm provides for the addition of new and termination of old sessions and maintains at all times feasibility of link flows with respect to capacity constraints. Fairness with respect to all sessions is built into the algorithm and a mechanism is provided to control link utilization and average delay per packet at any desired level.
Vortices and the SU(3) string tension

Abstract We present simulation results comparing the SU(3) heavy quark potential extracted from the full Wilson loop expectation to that extracted from the expectation of the Wilson loop fluctuation solely by elements of Z(3). The two potentials are found to coincide. This agreement is stable under multiple smoothings of the configurations which remove short distance fluctuations, and thus reflects long-distance physics. It strongly indicates that the asymptotic string tension arises from thick center vortices linking with the Wilson loop.
Change of the plane of oscillation of a Foucault pendulum from simple pictures

The change of the plane of oscillation of a Foucault pendulum is calculated without using equations of motion, the Gauss–Bonnet theorem, parallel transport, or assumptions that are difficult to explain.
Three-dimensional strip-integral method for incompressible turbulent boundary layers

A three-dimensional, strip-integral method was developed to calculate incompressible turbulent boundary layers. The entrainment coefficient is not required and no empirical relation is needed for the skin-friction coefficient. The Boussinesq assumption is used for the Reynolds stresses, and the eddy viscosity is defined using an extended Clauser outer region model. A practical four-parameter velocity profile was formulated: the streamwise velocity is represented by a new law of the wake based on the Johnston law of the wall and the Moses wake function. The crosswise velocity is represented by the Johnston triangular model
The Effect of Shareholder‐Level Dividend Taxes on Stock Prices: Evidence from the Revenue Reconciliation Act of 1993

We investigate the effect of an increase in the individual (shareholder‐level) income tax rate on share values. We regress cumulative daily abnormal stock returns surrounding the passage of the Revenue Reconciliation Act of 1993 on firm dividend yield, tax status of the investor as represented by level of institutional ownership, the interaction of these two variables, and control variables. Consistent with our expectations, we find that (1) the higher the firm's dividend yield, the more negative the firm's stock price reaction to the increase in the individual income tax rate (i.e., the dividend tax rate) enacted in the Revenue Reconciliation Act of 1993, and (2) institutional holdings mitigate this negative reaction. Our results suggest that both the dividend policy of the firm and the tax status of the marginal investor influence the extent to which dividend taxes are reflected in share values. Our evidence is consistent with the traditional view that firm dividend policy influences the extent to which...
Conformal orthosymplectic quantum mechanics

We present the most general curvature obstruction to the deformed parabolic orthosymplectic symmetry subalgebra of the supersymmetric quantum mechanical models recently developed to describe Lichnerowicz wave operators acting on arbitrary tensors and spinors. For geometries possessing a hypersurface-orthogonal homothetic conformal Killing vector we show that the parabolic subalgebra is enhanced to a (curvature-obstructed) orthosymplectic algebra. The new symmetries correspond to time-dependent conformal symmetries of the underlying particle model. We also comment on generalizations germane to three dimensions and new Chern–Simons-like particle models.
What would it mean to blog on the semantic web

The phenomenon known as Web logging (''blogging'') has helped realize an initial goal of the Web: to turn Web content consumers (i.e., end users) into Web content producers. As the Semantic Web unfolds, we feel there are two questions worth posing: (1) do blog entries have semantic structure that can be usefully captured and exploited? (2) Is blogging a natural way to encourage growth of the Semantic Web? We explore empirical evidence for answering these questions in the affirmative and propose means to bring blogging into the mainstream of the Semantic Web, including ontologies that extend the RSS 1.0 specification and an XSL transform for handling RSS 0.9x/2.0 files. To demonstrate the validity of our approach we have constructed a semantic blogging environment based on Haystack. We argue that with tools such as Haystack, semantic blogging will be an important paradigm by which metadata authoring will occur in the future.
A MONTE CARLO CODE FOR RELATIVISTIC RADIATION TRANSPORT AROUND KERR BLACK HOLES

We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.
Protected amino acid tetrafluorophenyl esters for peptide synthesis

New 2,3,5,6-tetrafluorophenyl active esters of protected amino acids useful for peptide synthesis were prepared in high yield. For certain amino acid derivatives such as Boc-Pro-OH, Boc-Ile-OH, and Boc-Val-OH, their tetrafluorophenyl esters have significantly higher melting points than the corresponding pentafluorophenyl esters. Kinetic studies were carried out to compare the racemization rate constants (with triethylamine) and coupling rate constants (with valine methyl ester) of the tetrafluorophenyl and pentafluorophenyl esters of protected histidine and tyrosine. Results of the second-order kinetics showed similarly large kcoupling/kracemization ratios for both tetra- and pentafluorophenyl esters. In particular, the use of 2,3,5,6-tetrafluorophenyl or pentafluorophenyl ester prevents extensive racemization of the N-tert.-butyloxycarbonyl-Nim-benzyl-histidine.
AES and RBS analysis of laser mixed Cr and Ni multilayer films on Cu alloys

Abstract The chemical analysis of Cr and Ni multilayer films laser mixed with Cu alloy substrates has been carried out with Auger electron and Rutherford backscattering spectroscopies. For multilayer transition metal on metal systems, such as Cu/Cr/Ni, the complementary use of both AES and RBS results in a more detailed understanding of the laser mixed compositional profiles than would result from the application of either technique alone. The relative strengths and weaknesses of both analytical methods are pointed out.
Study of van der Waals bonding and interactions in metal organic framework materials

Metal organic framework (MOF) materials have attracted a lot of attention due to their numerous applications in fields such as hydrogen storage, carbon capture and gas sequestration. In all these applications, van der Waals forces dominate the interaction between the small guest molecules and the walls of the MOFs. In this review article, we describe how a combined theoretical and experimental approach can successfully be used to study those weak interactions and elucidate the adsorption mechanisms important for various applications. On the theory side, we show that, while standard density functional theory is not capable of correctly describing van der Waals interactions, functionals especially designed to include van der Waals forces exist, yielding results in remarkable agreement with experiment. From the experimental point of view, we show examples in which IR adsorption and Raman spectroscopy are essential to study molecule/MOF interactions. Importantly, we emphasize throughout this review that a combination of theory and experiment is crucial to effectively gain further understanding. In particular, we review such combined studies for the adsorption mechanism of small molecules in MOFs, the chemical stability of MOFs under humid conditions, water cluster formation inside MOFs, and the diffusion of small molecules into MOFs. The understanding of these phenomena is critical for the rational design of new MOFs with desired properties.