cssi/SciSciGPT-SciSciNet huggingface dataset:
Elemental fractionations among enstatite chondrites

Abstract Neutron activation data on 14 elements in eight enstatite-chondrite falls are reported. These and literature data on an additional 28 elements show that intragroup elemental fractionations generally fall into one of three basic patterns: 1. (1) siderophilic- and chalcophilic-element abundances are about 1.5 times greater in E4-5 than in E6 chondrites; 2. (2) non-volatile lithophile-element abundances in E4-5 chondrites are generally about 1.0–1.2 times those in E6 chondrites; 3. (3) highly volatile elements are higher in E4-5 chondrites than in E6 chondrites by factors of 6–50. In addition, abundances (relative to Si) of most refractory and volatile elements are lower (by factors of 0.5–0.9) in E4 chondrites than in C1 chondrites. Because of the compositional hiatus often observed between E4-5 and E6 chondrites, there exists the distinct possibility that they are separate groups which were stored in different parent bodies. However, because of their close similarity in oxidation state, it seems likely that they originated at the same nebular location, far removed from the formation locations of the other, much more oxidized groups of chondrites. The E-group fractionation patterns can be plausibly explained in terms of four fractionation processes: 1. (1) loss of oxidizing agents (i.e. H 2 O) and refractory materials from starting materials of solar composition: 2. (2) partial loss of moderately volatile elements, perhaps as a result of gradual loss of nebular gas during condensation; 3. (3) more efficient agglomeration of metal particles than silicate particles; and 4. (4) increase of nebular temperatures during agglomeration-accretion resulting in the loss of volatile-rich late condensates from E6 chondrites. The low degree of oxidation of enstatite chondrite materials is best understood in terms of a fractionated nebula. At a pressure of 10 −4 atm the Si content of E4 metal can be produced at 1350°K if the H 2 O H 2 ratio is 5 times lower than that in unfractionated solar-system material. A nebula-wide fractionation process involving radial transport of refractories and H 2 O is indicated, and a suitable model in which the nebula-wide mixing of the gas phase continues during condensation is proposed.
Higher order terms in the Melvin-Morton expansion of the colored Jones polynomial

We formulate a conjecture about the structure of “upper lines” in the expansion of the colored Jones polynomial of a knot in powers of (q−1). The Melvin-Morton conjecture states that the bottom line in this expansion is equal to the inverse Alexander polynomial of the knot. We conjecture that the upper lines are rational functions whose denominators are powers of the Alexander polynomial. We prove this conjecture for torus knots and give experimental evidence that it is also true for other types of knots.
Efficient simplex computation for fixture layout design

Fixture, to hold an object by making multiple contacts, is a fundamental tool in manufacturing. A fixture layout is an arrangement of contacts on an object's surface. Designing a fixture layout of an object can be reduced to computing the largest simplex and the resulting simplex is classified using the radius of the largest inscribed ball centered at the origin. We present three different algorithms to compute such a simplex: a simple randomized algorithm, an interchange algorithm, and a branch-and-bound algorithm. We also present methods to combine different algorithms to improve the performance and highlight their performance on complex 3D models consisting of thousands of triangles. Our randomized algorithm computes a feasible fixture layout in linear time and is well-suited for real-time applications. The interchange algorithm computes an optimal simplex in linear time such that no single vertex can be changed to enlarge the simplex, and it provides a practical method for complex 3D objects. The branch-and-bound algorithm computes the largest simplex by using lower and upper bounds on the radius of the inscribed ball, by which the computation time is reduced by a factor of five in comparison with the brute-force search.
Probing Red Giant Atmospheres with Gravitational Microlensing

Gravitational microlensing provides a new technique for studying the surfaces of distant stars. Microlensing events are detected in real time and can be followed up with precision photometry and spectroscopy. This method is particularly adequate for studying red giants in the Galactic bulge. Recently we developed an efficient method capable of computing the lensing effect for thousands of frequencies in a high-resolution stellar spectrum. Here we demonstrate the effects of microlensing on synthesized optical spectra of red giant model atmospheres. We show that different properties of the stellar surface can be recovered from time-dependent photometry and spectroscopy of a point-mass microlensing event with a small impact parameter. In this study we concentrate on center-to-limb variation of spectral features. Measuring such variations can reveal the depth structure of the atmosphere of the source star.
Selecting forwarding neighbors in wireless ad hoc networks

Broadcasting is a fundamental operation which is frequent in wireless ad hoc networks. A simple broadcasting mechanism, known as flooding, is to let every node retransmit the message to all its 1-hop neighbors when receiving the first copy of the message. Despite its simplicity, flooding is very inefficient and can result in high redundancy, contention, and collision. One approach to reducing the redundancy is to let each node forward the message only to a small subset of 1-hop neighbors that cover all of the node's 2-hop neighbors. In this paper we propose two practical heuristics for selecting the minimum number of forwarding neighbors: an O(n log n)time algorithm that selects at most 6 times more forwarding neighbors than the optimum, and an O(n log2 n) time algorithm with an improved approximation ratio of 3, where n is the number of 1- and 2-hop neighbors. The best previously known algorithm, due to Bronnimann and Goodrich [2], guarantees O(1) approximation in O(n3 log n)time.
New chemical and biological aspects of artemisinin-derived trioxane dimers.

Abstract Joining two 10-deoxoartemisinin trioxane units via a p -diacetylbenzene linker produces new C-10 non-acetal dimers 3b and 3c . 1 H NMR spectroscopy allows unambiguous assignment of the stereochemistry at C-10 in these dimers. Successful replacement of both carbonyl oxygen atoms in these diketone dimers by fluorine atoms produces new tetrafluorinated dimers 5a and 5b . Each dimer was evaluated in vitro for antimalarial, antiproliferative, and antitumor activities; ketone dimers 3b and 3c , more than fluorinated dimers 5a and 5b , are promising for chemotherapy of both malaria and cancer.
New Synthetic Approaches to Polycyclic Aromatic Hydrocarbons and Their Carcinogenic Oxidized Metabolites: Derivatives of Benzo[s]picene, Benzo[rst]pentaphene, and Dibenzo[b,def]chrysene

A new synthetic approach to polycyclic aromatic compounds is described that entails in the key steps double Suzuki coupling of PAH bisboronic acid derivatives with o-bromoaryl aldehydes to furnish aryl dialdehydes that are converted to larger polycyclic aromatic ring systems by either (a) conversion to diolefins by Wittig reaction followed by photocyclization or (b) reductive cyclization with triflic acid and 1,3-propanediol. This synthetic method provides convenient access to as many as three different polycyclic aromatic ring systems from a single Suzuki coupled intermediate. It was utilized to synthesize substituted derivatives of benzo[s]picene, benzo[rst]pentaphene, dibenzo[b,def]chrysene, and 13,14-dihydro-benz[g]indeno[2,1-a]fluorene, as well as the putative carcinogenic bisdihydrodiol metabolites of benzo[s]picene, benzo[rst]pentaphene, and dibenzo[b,def]chrysene.
Substantial reduction of Stone-Wales activation barrier in fullerene

Stone-Wales (SW) transformation is a key mechanism responsible for the growth, transformation, and fusion in fullerenes, carbon nanotubes, and other carbon nanostructures. These topological defects also substantially alter the physical and chemical properties of the carbon nanostructures. However, this transformation is thermodynamically limited by very high activation energy ($\ensuremath{\sim}7\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$ in fullerenes). Using first-principles density functional calculations, we show that the substitutional boron doping substantially reduces the SW activation barrier (from $\ensuremath{\sim}7$ to 2.54 eV). This reduction is the largest in magnitude among all the mechanisms of barrier reduction reported to date. Analysis of bonding charge density and phonon frequencies suggests that the bond weakening at and around the active SW site in B heterofullerenes is responsible for such a reduction. Therefore, the formation of the SW defect is promoted in such heterofullerenes and is expected to affect their proposed ${\mathrm{H}}_{2}$ storage properties. Such substitutional doping also can modify the SW activation barrier in carbon nanotubes and graphene nanostructures and can catalyze isomerization, fusion, and nanowelding processes.
Yield stress in metallic glasses: The jamming-unjamming transition studied through Monte Carlo simulations based on the activation-relaxation technique

A Monte Carlo approach allowing for stress control is employed to study the yield stress of a twodimensional metallic glass in the limit of low temperatures and long infinite time scales. The elementary thermally activated events are determined using the activation-relaxation technique ART. By tracking the minimum-energy state of the glass for various applied stresses, we find a well-defined jamming-unjamming transition at a yield stress about 30% lower than the steady-state flow stress obtained in conventional straincontrolled quasistatic simulations. ART is then used to determine the evolution of the distribution of thermally activated events in the glass microstructure both below and above the yield stress. We show that aging below the yield stress increases the stability of the glass, both thermodynamically the internal potential energy decreases and dynamically the aged glass is surrounded by higher-energy barriers than the initial quenched configuration. In contrast, deformation above the yield stress brings the glass into a high internal potential energy state that is only marginally stable, being surrounded by a high density of low-energy barriers. The strong influence of deformation on the glass state is also evidenced by the microstructure polarization, revealed here through an asymmetry of the distribution of thermally activated inelastic strains in glasses after simple shear deformation.
Lift Enhancement by an Externally Trapped Vortex

A theoretical study is made of the performance capabilities of a lift concept that utilizes a spanwise vortex over the upper surface of the wing. The vortex is generated by a vertical flap near the leading edge of the wing and maintained by suction through orifices in endplates at the wingtip. The analysis approximates the three-dimensional flow field with a two-dimensional configuration that is mapped by conformal transformation into the flow about a circle. Theoretical solutions for a range of flap and orifice configurations predict that section lift coefficients up to around 10 can be achieved. It is concluded that such a lift concept is applicable to STOL aircraft if the vortex can be adequately stabilized and if the endplate suction can be generated efficiently.
Surviving the global financial crisis : foreign ownership and establishment performance

This paper examines how different establishments performed during the recent global financial crisis, focusing on the role of foreign ownership. The paper investigates how foreign ownership affected establishments' responses to negative economic shocks, using a cross-country panel dataset with detailed information on operation, location and industry for more than 12 million establishments from 2005-2008. The evidence shows that multinational subsidiaries on average fared better than local counterfactuals with similar economic characteristics. Among multinational subsidiaries, establishments with stronger production and financial linkages with parent companies showed greater resilience. Finally, in contrast to the crisis period, the impact of foreign ownership and linkages on an establishment's performance was insignificant in non-crisis years.
Convexity Properties of the Moment Mapping Re-examined☆

Abstract Consider a Hamiltonian action of a compact Lie group on a compact symplectic manifold. A theorem of Kirwan's says that the image of the momentum mapping intersects the positive Weyl chamber in a convex polytope. I present a new proof of Kirwan's theorem, which gives explicit information on how the vertices of the polytope come about and on how the shape of the polytope near any point can be read off from infinitesimal data on the manifold. It also applies to some interesting classes of noncompact or singular Hamiltonian spaces, such as cotangent bundles and complex affine varieties.
Constraints on the Birth Aggregate of the Solar System

Using the observed properties of our Solar System, in particular the isotopic compositions of meteorites and the regularity of the planetary orbits, we constrain the star formation environment of the Sun within the scenario of (external) radioactive enrichment by a massive star. This calculation yields a probability distribution for the number of stars in the solar birth aggregate. The Sun is most likely to have formed within a stellar group containing N=〈N〉≈2000±1100 members. The a priori probability of a star forming in this type of environment is P≈0.0085; i.e., only about 1 out of 120 solar systems are expected to form under similar conditions. We discuss additional implications of this scenario, including possible effects from the radiation fields provided by the putative cluster environment and dynamical disruption of the Kuiper Belt. The constraints of this paper place tight restrictions on the properties of the solar birth aggregate for the scenario of external enrichment by a massive star; alternately, these tight constraints slightly favor a self-enrichment scenario for the short-lived radioactive species.
Modeling and Analysis of Integrated Planning of Production and Engineering Process Improvement

A clearing function that can capture the nonlinear relationship between workloads and throughput and also reflect capacity improvement by engineering activities on a multioperation workcenter is developed. The clearing function is then used to formulate an integrated optimization model for planning both production and engineering process improvement. Marginal cost analysis using the Karush-Kuhn-Tucker optimality conditions provides useful insights into effective management of resources in a reentrant manufacturing system.
Trigeminal autonomic cephalalgias

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache syndromes all marked by headache and associated autonomic features. The TACs include cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing syndrome. Diagnosis is made after looking at headache frequency, duration, and accompanying symptoms. Each TAC has its own unique treatment modality, which is discussed in depth.
An Approach to the Synthesis of Stenine

A type 2 N-acylnitroso intramolecular Diels−Alder reaction followed by reductive N−O bond cleavage formed the B and C rings of the Stemona alkaloid stenine. Further elaboration provided the functionalized tricyclic core.
The on-line firing squad simulator

The purpose of this study is to investigate man/machine interaction in the context of solving a conceptually difficult, formal problem. We want a problem that requires no specialized knowledge, so that a fair comparison can be made between computer-aided and unaided attempts at solution. We also want a problem that is graphic. The firing squad synchronization problem satisfies these criteria extremely well. It has the added advantage that no optimal solution has yet been produced.
Direct biooxidation of arenes to corresponding catechols with E. coli JM109 (pDTG602). Application to synthesis of combretastatins A-1 and B-1

Convergent syntheses of combretastatins A-1 and B-1 were accomplished via coupling of biocatalytically generated p-bromomethoxycatechol with trimethoxyphenylacetylene.
New Properties of Matter in (A)dS and their Consequences

I review briefly, primarily for relativists, a series of recent results, obtained with A. Waldron, on the novel behavior of massive higher (s > 1) spin systems in constant curvature backgrounds. We find that the cosmological constant Λ, together with the mass parameter, define a "phase plane" in which partially massless gauge invariant lines separate allowed regions from forbidden, non-unitary, ones. These lines represent short multiplet systems, with missing lower helicities, removed by novel local gauge invariances, and (despite having m ≠ 0) propagating on the light cone. In the limit of an infinite tower of these higher spin bosons and fermions, unitarity requires Λ to vanish.
On Completeness under Random Reductions

In this paper, we study the notion of completeness under random reductions and explore how that depends on the type and success probability of the reduction. We obtain absolute separations between completeness notions under various random reductions and between random reductions and deterministic reductions. These separations are obtained in appropriately high complexity classes where these questions do not have contradictory relativizations. Our results show that the notion of completeness under random reductions is sensitive tovery smallchanges in success probability, since we can separate completeness under reductions with very small differ- ences in success probability. We also obtain optimal separations between completeness under various deterministic reductions and random reductions.
FePt Magnetic Nanoparticles and Their Assembly for Future Magnetic Media

Magnetic nanoparticles with extremely high anisotropy such as chemically ordered L10 phase FePt nanoparticles have been considered one of the best candidates for future magnetic recording media with areal density beyond 1 Tbit/in2 for either the nanocomposite-film-type heat-assisted magnetic recording (HAMR) media or the self-organized-magnetic-array (SOMA)-type bit patterned media. However, current preparation methods via phase transformation must overcome many obstacles, including particle agglomeration, twinning, and difficulty of easy axis alignment. In this paper, the effort on and promise of the preparation of monodispersed magnetic nanoparticles with high anisotropy by a gas phase condensation method is reviewed and reported. The focus is to review recent progress on the fabrication of monodispersed highly ordered L10 phase FePt nanoparticles without phase transformation, successfully self-assembled and magnetically aligned magnetic nanoparticles for SOMA and HAMR media. The mechanisms for directly forming L10 phase FePt nanoparticles during nucleation and growth processes and magnetically aligning these particles are analyzed.
Market Efficiency and Marketing to Enhance Income of Crop Producers

Recent changes in farm policy have renewed interest in using marketing strategies based on futures and options markets to enhance the income of field crop producers. This article reviews the main concepts and associated empirical research of the dominant academic theory concerning the behavior of futures and options markets, namely, the efficient market hypothesis. This rich conceptual and empirical base provides several important insights. One is that, although individuals can beat the market, few can consistently do so. This insight is consistent with Grossman and Stiglitz's model of market efficiency, in which individuals who consistently earn trading returns have superior access to information or superior analytical ability. One implication is that, with few exceptions, the crop producers who survive will be those with the lowest cost of production because efforts to improve revenue through better marketing will have limited success. Some successful marketing strategies do appear to exist, but generally they are based on using the market as a source of information. One example is to base storage decisions on whether the current basis exceeds the cost of storage and then to use hedging to ensure an expected positive return.
Latest results from PHOBOS

This paper contains a summary of the latest physics results from PHOBOS, as reported at Quark Matter 2006. Highlights include the first measurement from PHOBOS of dynamical elliptic flow fluctuations as well as an explanation of their possible origin, two-particle correlations, identified particle ratios, identified particle spectra and the latest results in global charged particle production.
Leed Study of the Adhesion of Copper and Tungsten to the (111) Surface of Nickel

Adhesion studies were conducted with copper, tungsten and oxidized tungsten contacting a nickel (111) surface. The copper, tungsten and oxidized tungsten were 1 mm diameter flat ended fibers. They contacted the nickel surface at loads of 20 to 150 milligrams with surface contact times of 10 to 300 seconds. The nickel (111) surface was examined before and after adhesion contact with LEED. With clean metals in adhesive contact, fracture in tension occurred in the lower cohesive strength material. When copper contacted nickel, a surface alloy formed. The adhesion of clean nickel to an oxidized tungsten surface resulted in oxygen transfer from tungsten to nickel with atomic surface rearrangement of the oxygen. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Houston, Texas, October 14–16, 1969
ORIENTATIONS IN LEGENDRIAN CONTACT HOMOLOGY AND EXACT LAGRANGIAN IMMERSIONS

We show how to orient moduli spaces of holomorphic disks with boundary on an exact Lagrangian immersion of a spin manifold into complex n-space in a coherent manner. This allows us to lift the coefficients of the contact homology of Legendrian spin submanifolds of standard contact (2n + 1)-space from ℤ2 to ℤ. We demonstrate how the ℤ-lift provides a more refined invariant of Legendrian isotopy. We also apply contact homology to produce lower bounds on double points of certain exact Lagrangian immersions into ℂn and again including orientations strengthens the results. More precisely, we prove that the number of double points of an exact Lagrangian immersion of a closed manifold M whose associated Legendrian embedding has good DGA is at least half of the dimension of the homology of M with coefficients in an arbitrary field if M is spin and in ℤ2 otherwise.
DART: a toolkit for rapid design exploration of augmented reality experiences

In this paper [MacIntyre et al 2004]. we describe The Designer's Augmented Reality Toolkit (DART). DART is built on top of Macromedia Director, a widely used multimedia development environment. We summarize the most significant problems faced by designers working with AR in the real world, and discuss how DART addresses them. Most of DART is implemented in an interpreted scripting language, and can be modified by designers to suit their needs. Our work focuses on supporting early design activities, especially a rapid transition from storyboards to working experience, so that the experiential part of a design can be tested early and often. DART allows designers to specify complex relationships between the physical and virtual worlds, and supports 3D animatic actors (informal, sketch-based content) in addition to more polished content. Designers can capture and replay synchronized video and sensor data, allowing them to work off-site and to test specific parts of their experience more effectively.
Asynchronous Orthogonal Differential Decoding for Multiple Access Channels

We propose several differential decoding schemes for asynchronous multi-user MIMO systems based on orthogonal space–time block codes (OSTBCs), where neither the transmitters nor the receiver has knowledge of the channel. First, we derive novel low complexity differential decoders by performing interference cancellation in time and employing different decoding methods. The decoding complexity of these schemes grows linearly with the number of users. We then present additional differential decoding schemes that perform significantly better than our low complexity decoders and outperform the existing synchronous differential schemes but require higher decoding complexity compared to our low complexity decoders. The proposed schemes work for any square OSTBC, any constant amplitude constellation, any number of users, and any number of receive antennas. Furthermore, we analyze the diversity of the proposed schemes and derive conditions under which our schemes provide full diversity. For the cases of two and four transmit antennas, we provide examples of PSK constellations to achieve full diversity. Simulation results show that our differential schemes provide good performance. To the best of our knowledge, the proposed differential detection schemes are the first differential schemes for asynchronous multi-user systems.
Effects of Socio-Economic and Input-Related Factors on Polluting Plants' Location Decisions

Many environmental justice studies argue that firms choose to locate waste sites or polluting plants disproportionately in minority or poor communities. However, it is not uncommon for these studies to match site or plant location to contemporaneous socioeconomic characteristics instead of to characteristics at the time of siting. While this may provide important information on disproportionate impacts currently faced by these communities, it does not describe the relationship at the time of siting. Also, variables that are important to a plant's location decision i.e., production and transportation costs are often not included. Without controlling for such variables, it is difficult to evaluate the relative importance of socioeconomic characteristics in a firm's initial location decision. This paper examines the role of community socioeconomic characteristics at the time of siting in the location decisions of manufacturing plants while controlling for other location-relevant factors such as input costs.When plant location is matched to current socioeconomic characteristics, results are consistent with what the environmental justice literature predicts: race is significant and positively related to plant location, while income is significant and negatively related to plant location. When plant location is matched to socioeconomic characteristics at the time of siting, empirical results suggest that race is no longer significant, though income is still significant and negatively related to plant location. Poverty rates are sometimes significant but act as a deterrent to plant location. Variables traditionally considered in the firm location literature such as land and labor costs, the quality of labor, and distance to rail are significant. The presence of pre-existing TRI plants in a neighborhood and average plant size are also significant.
Incremental Acquisition of a Three-Dimensional Scene Model from Images

We describe the current state of the 3-D Mosaic project, whose goal is to incrementally acquire a 3-D model of a complex urban scene from images. The notion of incremental acquisition arises from the observations that 1) single images contain only parfial information about a scene, 2) complex images are difficult to fully interpret, and 3) different features of a given scene tend to be easier to extract in different images because of differences in viewpoint and lighting conditions. In our approach, multiple images of the scene are sequentially analyzed so as to incrementaly construct the model. Each new image provides information which refines the model. We describe some experiments toward this end. Our method of extracting 3-D shape information from the images is stereo analysis. Because we are dealing with urban scenes, a junction-based matching technique proves very useful. This technique produces rather sparse wire-frame descriptions of the scene. A reasoning system that relies on task-specific knowledge generates an approximate model of the scene from the stereo output. Gray scale information is also acquired for the faces in the model. Finally, we describe an experiment in combining two views of the scene to obtain a rermed model.
Directional neighbor discovery in 60 GHz indoor wireless networks

Signal propagation in the 60 GHz band significantly differs from that in the 2.4 and 5 GHz bands. In particular, the signals are often reflected in indoor settings in this band. Directional antennas can help limit the impact of reflection, but make the process of neighbor discovery complex. We consider this problem in this paper. We examine two approaches (a) direct discovery where each node explicitly discovers its neighbors, and (b) gossip-based discovery where nodes exchange information about their already discovered neighbors. We analyze the two approaches and validate our models via simulations. We examine the impact of system parameters such as varying beamwidth and node density.
Generation of photon number states

The visible light photon counter (VLPC) has the capability to discriminate photon number states, in contrast to conventional photon counters which can only detect the presence or absence of photons. We use this capability, along with the process of parametric down-conversion, to generate photon number states. We experimentally demonstrate generation of states containing 1, 2, 3 and 4 photons with high fidelity. We then explore the effect the detection efficiency of the VLPC has on the generation rate and fidelity of the created states.
Stereoselective Synthesis of Spirocyclic Oxindoles via Prins Cyclizations

The synthesis of spirocyclic oxindole pyran and oxepene frameworks using highly stereoselective Prins cyclizations of homoallylic and bis-homoallylic alcohols and isatin ketals is described.
Substitution reactions of (diphosphine)palladium(II) and -platinum(II) chloride and triflate complexes

Abstract The triflate complexes [Pd(OTf)2L2] (L2 = dppm, dppe, dppp) and [Pt(OTf)2(dppp)] are prepared by reaction of the corresponding chloride with methyl triflate. The chloropalladium complexes [PdCl2L2] do not react with PPh3, but with PBu3 substitution of one chloride takes place, whereas [PtCl2(dppp)] reacts with either PPh3 or PBu3. The triflate complexes [M(OTf)2L2] (M = Pd, Pt; L2 = dppm, dppe, dppp) react with either PPh3 or PBu3 by substitution of one or both triflate ligands, although in CDCl3 the system is complicated by reaction with the solvent. [Pt(cod)(dppp)][OTf]2 reacts with PPh3 or PBu3 by attack of the phosphine on one of the double bonds of cyclooctadiene.
Synthesis of 5-phenylnaphtho[1,2-b]benzofuran by ambident alkylation of 1-naphthol

Reaction of 1-naphthol with 2-chlorocyclohexanone in alkaline alcohol gave as the major product 5-(2′-oxocyclohexyl)-7,8,9,10-tetrahydronaphtho[1,2-b]benzofuran (1), which could be converted to the title compound 5 by reduction and dehydrogenation. This product arises from ambident alkylation of 1-naphthol at the 2-and 4-positions. Via the 2′-oxocyclohexyl ether, 5 was also synthesized from 4-phenyl-1-naphthol.
Time-varying risk premia in foreign exchange and equity markets: evidence from Asia–Pacific countries

Abstract This paper examines the validity of the risk premia hypothesis in explaining deviations from Uncovered Interest Parity (UIP) and the role of deviations from Purchasing Power Parity (PPP) in the pricing of foreign exchange rates and equity securities in five Asia–Pacific countries and the US. Using weekly data from 1 January, 1988 to 27 February, 1998, I find that conditional variances are not related to the deviations from UIP in any statistical sense based on an univariate GARCH(1,1)-M model. As I consider both foreign exchange and equity markets together and test a conditional international CAPM (ICAPM) in the absence of PPP, I cannot reject the model based on the J-test by Hansen (Econometrica 50 (1982), 1029–1054) and find significant time-varying foreign exchange risk premia present in the data. This empirical evidence supports the notion of time-varying risk premia in explaining the deviations from UIP. It also supports the idea that the foreign exchange risk is not diversifiable and hence should be priced in both markets.
IMPROVED STANDARDIZATION OF TYPE II-P SUPERNOVAE: APPLICATION TO AN EXPANDED SAMPLE

In the epoch of precise and accurate cosmology, cross-confirmation using a variety of cosmographic methods is paramount to circumvent systematic uncertainties. Owing to progenitor histories and explosion physics differing from those of Type Ia supernovae (SNeIa), Type II-plateau supernovae (SNeII-P) are unlikely to be affected by evolution in the same way. Based on a new analysis of 17 SNeII-P, and on an improved methodology, we find that SNeII-P are good standardizable candles, almost comparable to SNeIa. We derive a tight Hubble diagram with a dispersion of 10% in distance, using the simple correlation between luminosity and photospheric velocity introduced by Hamuy and Pinto. We show that the descendent method of Nugent etal. can be further simplified and that the correction for dust extinction has low statistical impact. We find that our SN sample favors, on average, a very steep dust law with total to selective extinction RV < 2. Such an extinction law has been recently inferred for many SNeIa. Our results indicate that a distance measurement can be obtained with a single spectrum of a SNII-P during the plateau phase combined with sparse photometric measurements. © 2009. The American Astronomical Society. All rights reserved.
High‐latitude ionospheric drivers and their effects on wind patterns in the thermosphere

Winds in the thermosphere are highly important for transporting mass, momentum, and energy over the globe. In the high-latitude region, observations show that ion and neutral motions are strongly coupled when the aurora is present but the coupling is less evident when there is no aurora. In this study, we investigate the ability of the Global Ionosphere-Thermosphere Model (GITM) to simulate the mesoscale wind structure over Alaska during a substorm. Thirteen distinct numerical simulations of a substorm event that occurred between 02:00 and 17:00 Universal Time on 24 November 2012 have been performed. Distinct drivers considered include the Weimer and SuperDARN potential patterns and the OVATION Prime and OVATION-SME auroral models. The effects of the boundary between the neutral wind dynamo calculation and the high-latitude imposed electric potential were also considered. Neutral wind velocities and thermospheric temperatures measured by the Scanning Doppler Imager instruments located at three locations in Alaska were compared to GITM simulation results, and electron densities within GITM were compared to data from the Poker Flat Incoherent Scatter Radar. It was found that the different drivers used between multiple simulations lead to various amounts of momentum coupling within the simulation, affecting the accuracy of the modeled neutral and ion flow patterns and the strength of electron precipitation at high latitudes. This affirms that better observations of auroral precipitation and electric fields are required to accurately understand and consistently reproduce the mesoscale neutral wind flow patterns and temperature structure in the high-latitude thermosphere.
microGPS: On‐Orbit Demonstration of a New Approach to GPS for Space Applications

: In February 1998, the Student Nitric Oxide Explorer (SNOE) was successfully launched and began scientific observations. In addition to three instruments designed by the University of Colorado's Laboratory of Atmospheric and Space Physics to study nitric oxide in the atmosphere, the spacecraft carried a 600 gram GPS receiver designed and built by the Jet Propulsion Laboratory (JPL). This receiver, known as microGPS, is a combination of simple low-power hardware and portable, efficient software that was developed by JPL for spacecraft navigation in earth orbit. It is intended for micro- and nano-satellite applications in which mass and power budget margins are especially limited or as a robust second string to a conventional GPS receiver on board any satellite. This paper describes on-orbit operational experience with the microGPS receiver on the SNOE spacecraft. It also previews the next-generation, dual-frequency microGPS receiver, to be launched in 2000 on the Space Technology Research Vehicle (STRV-1c), a geostationary transfer orbit spacecraft. Comparisons are made between the expected performance of microGPS and actual observations. The design, expected, and actual performance of the orbit determination software, which is rooted in the techniques and algorithms pioneered in JPL's high-accuracy GIPSY/OASIS II software, is also described.
Market Valuation of Successful versus Non-successful R&D Efforts in the Pharmaceutical Industry

This paper examines the relationship between a non-financial meas- ure of successful research and development (RD however, the coefficient on the interaction between R&D and successful developers is positively related to stock price. This implies that the market values the R&D expenditures of successful developers but not the expenditures of less-successful developers.
A Nonequilibrium Thermal Model for Rapid Heating and Pyrolysis of Organic Composites

A nonequilibrium thermal model is developed to predict the through-thickness transient temperature variation in organic composites subjected to intensive heating. In addition to heat conduction, the model incorporates four important mechanisms: rate-dependent pyrolysis, pyrolysis by-product outgassing, irradiance-dependent convection heat loss, and radiation heat lose. Both the shape of the gas flow channel and the gas addition velocity from the channel wall are evaluated based on the decomposition reaction rate. The through-thickness temperature transients, the continually changing gas channel, and the pressure distribution in the decomposition gas are obtained and discussed.
A Phase II Trial of Paclitaxel in Refractory Germ Cell Tumors

BACKGROUND A significant percentage of patients with refractory germ cell tumors will not respond to standard salvage regimens. Thus there is a need for new active agents. Paclitaxel has demonstrated activity against a variety of solid tumors in both laboratory and clinical studies. METHODS Eighteen patients with refractory germ cell tumors who failed initial cisplatin-based chemotherapy and a maximum of 2 salvage regimens were enrolled into a Phase II trial of paclitaxel at a dose of 170 mg/m2 by intravenous infusion over 24 hours every 21 days without growth factor support. The median age of the patients was 32.5 years (range, 18-49 years). The testis was the primary site of tumor for 13 patients (72%) and the tumor was extragonadal in 5 patients (28%). Six patients (33%) were late recurrences. Twelve patients (67%) had ≥2 metastatic sites. The median number of previous chemotherapy cycles was six (range, four to nine). Three patients (17%) previously had undergone autologous bone marrow transplantation. RESULTS Two patients (11%) responded to paclitaxel. Major toxicities were Grade 3-4 neutropenia (55% of patients) and Grade 3-4 neurotoxicity (2 patients). Neutropenic fever occurred in 3 patients (17%). CONCLUSIONS Paclitaxel demonstrated minimal activity in heavily pretreated patients with multiple, poor risk clinical features. These results in part may be due to the unfavorable characteristics of the patients in the current study, specifically the high percentage of patients with late recurrences and extragonadal primary tumors, both of which are known to respond poorly to salvage therapy. Other trials with different patient populations and doses of paclitaxel reported response rates ranging from 13.3%-26%. The role of paclitaxel in the treatment of patients with refractory germ cell tumors remains to be defined in future studies. Cancer 1998;82:1381-6. © 1998 American Cancer Society.
Periodic discrete energy for long-range potentials

We consider periodic energy problems in Euclidean space with a special emphasis on long-range potentials that cannot be defined through the usual infinite sum. One of our main results builds on more recent developments of Ewald summation to define the periodic energy corresponding to a large class of long-range potentials. Two particularly interesting examples are the logarithmic potential and the Riesz potential when the Riesz parameter is smaller than the dimension of the space. For these examples, we use analytic continuation methods to provide concise formulas for the periodic kernel in terms of the Epstein Hurwitz Zeta function. We apply our energy definition to deduce several properties of the minimal energy including the asymptotic order of growth and the distribution of points in energy minimizing configurations as the number of points becomes large. We conclude with some detailed calculations in the case of one dimension, which shows the utility of this approach.
Shareholder protection, ownership concentration and FDI

Abstract Host country's weaker legal shareholder protection may make it costlier for parent shareholders to monitor the foreign subsidiary and hold managers accountable in case of misconduct. This prospect may motivate the managers to invest in such foreign environments. However, the agency costs associated with such investments can increase as well. The latter would tend to discourage such FDI. We test this ex ante uncertain relationship using a sample of publicly quoted UK parents that established new, majority owned joint venture subsidiaries in Continental Europe. We find that host country's weak legal shareholder protection discourages FDI. This negative relationship, however, is less important for firms with higher ownership concentration, implying that parent's ownership concentration may be a substitute for host country's weak legal shareholder protection.
Introduction to session on learning machines

The following four papers treat various levels of complexity in machine systems which exhibit learning ability. It is perhaps a misnomer to label such devices as "learning machines," since it is not the machine itself, but the program that guides the machine toward its goal, which learns. This topic is unfortunately suggestive of the considerable publicity that has attended the "Giant Brain" ballyhoo directed toward digital systems, but it is not the intention of these four papers to indicate how to make "thinking" machines. The first effort in this direction is a careful definition of "thinking," which no one has yet given. It should be very carefully emphasized that machines may be said to "think" only to the extent that their users and designers have been able to penetrate sufficiently deeply into a problem so that all possible situations which might arise have been examined, and an adequate program written which describes to the machine an unambiguous criterion for its use in each case. Machine operation which results from such subtle programs is then an imitation or simulation of operations which have previously been thought through and established by human beings.
Invertible bloom lookup tables

We present a version of the Bloom filter data structure that supports not only the insertion, deletion, and lookup of key-value pairs, but also allows a complete listing of the pairs it contains with high probability, as long the number of key-value pairs is below a designed threshold. Our structure allows the number of key-value pairs to greatly exceed this threshold during normal operation. Exceeding the threshold simply temporarily prevents content listing and reduces the probability of a successful lookup. If entries are later deleted to return the structure below the threshold, everything again functions appropriately. We also show that simple variations of our structure are robust to certain standard errors, such as the deletion of a key without a corresponding insertion or the insertion of two distinct values for a key. The properties of our structure make it suitable for several applications, including database and networking applications that we highlight.
A sensitivity study of the Enceladus torus

[1] We have developed a homogeneous model of physical chemistry to investigate the neutral-dominated, water-based Enceladus torus. Electrons are treated as the summation of two isotropic Maxwellian distributions: a thermal component and a hot component. The effects of electron impact, electron recombination, charge exchange, and photochemistry are included. The mass source is neutral H2O, and a rigidly corotating magnetosphere introduces energy via pickup of freshly ionized neutrals. A small fraction of energy is also input by Coulomb collisions with a small population (<1%) of suprathermal electrons. Mass and energy are lost due to radial diffusion, escaping fast neutrals produced by charge exchange and recombination, and a small amount of radiative cooling. We explore a constrained parameter space spanned by water source rate, ion radial diffusion, hot electron temperature, and hot electron density. The key findings are as follows: (1) radial transport must take longer than 12 days; (2) water is input at a rate of 100–180 kg s−1; (3) hot electrons have energies between 100 and 250 eV; (4) neutrals dominate ions by a ratio of 40:1 and continue to dominate even when thermal electrons have temperatures as high as ≈5 eV; (5) hot electrons do not exceed 1% of the total electron population within the torus; (6) if hot electrons alone drive the observed longitudinal variation in thermal electron density, then they also drive a significant variation in ion composition.
MARGINAL CONDITIONAL STOCHASTIC DOMINANCE, STATISTICAL INFERENCE, AND MEASURING PORTFOLIO PERFORMANCE

A simple statistical test is developed for marginal conditional stochastic dominance (MCSD). The MCSD is an extension of second-degree stochastic dominance. As such, without specification of the return-generating process, it can rank securities according to marginal changes of return distributions conditionally to the distribution of the market proxy, thereby proving a powerful technique for measuring portfolio performance. Although the MCSD test is asymptotic and conservative, under both the hypotheses of homoskedasticity and heteroskedasticity, it has power to detect the dominance alternative for samples with more than 300 observations. For an illustration, the MCSD test is applied to international equity markets. The test is able to show that nine of twenty-eight equity markets are dominated by the world market. JEL classification: G11, C49
Computer assisted instruction comes of age in a public school system

During the late 1960's a number of public schools began experimenting with the development and use of computer-assisted and computer-managed instruction. Funding for these public school projects was provided primarily by Title III of the Elementary and Secondary Education Act of 1965, or other sources of federal funds. Due to the reduced availability of federal funding, few new public school CAI projects have been initiated since 1970. It is, however, very encouraging to analyze the results of the few active public schools CAI projects.