cssi/SciSciGPT-SciSciNet huggingface dataset:
g = 1 for Dirichlet 0-branes

Abstract Dirichlet 0-branes, considered as extreme Type IIA black holes with spin carried by fermionic hair, are shown to have the anomalous gyromagnetic ratio g = 1, consistent with their interpretation as Kaluza-Klein modes.
Coincidence of composition and speed boundaries of the slow solar wind

[1] Recent studies have raised questions about the plasma characteristics that define what is called the “slow solar wind.” At issue is whether solar wind with low speed located far from the heliospheric current sheet (HCS) lacks the composition signatures characteristic of a streamer belt origin, where the streamer belt is understood to encompass the HCS. To test for this possibility, superposed epoch analysis of composition data at 1 AU was performed at stream interfaces. Since interfaces mark the boundary between what was originally fast and slow wind when it left the Sun, the analysis sidesteps the need to identify slow wind by its speed. At those interfaces where the slow wind precedes fast wind, the resulting pressure ridge creates an east-west flow deflection that identifies the boundary. The analysis of 258 interfaces displaying an unambiguous deflection reveals sharp drops in the ratios of O7+/O6+, C6+/C5+, and Fe/O coincident with interface passage. The coincidence indicates that essentially all slow wind, including slow wind from pseudostreamers, has ionic and elemental composition characteristic of the streamer belt, independent of distance from the HCS. This finding is not unexpected in view of the well-known drop in density and increase in proton temperature characteristic of interface passage. These parameters control entropy, which is well-correlated with O7+/O6+.
Heat Transmission Effects of Hetero-Material (Al-PZT) Direct Bonding on an In-Pipe Micro Inspection Machine

Al and PZT{Pb(Zr, Ti)O3} were directly bondable by forming hydrogen bonds at the interface. The strength of the bond and the structure of the interface were investigated. This technique was applied to the direct bonding between a PZT stacked actuator and an Al radiator plate on an in-pipe micro inspection machine, and the heat transmission effects of direct bonding on the micro inspection machine have been compared with the adhesive bonding.First, the Al and the PZT were treated so that their surfaces were hydrophilic, then OH groups were adsorbed by a physical reaction in which the surfaces are bombarded with ions produced by passing the steam through anion source. The surfaces were then placed in contact with each other in the air, then heated above 250°C in a vacuum to remove the residual water molecules from the bonding interface.The observation with a thermo-viewer shows that the saturated temperature of the PZT stacked actuator at the driving frequency of 1kHz is suppressed below 93°C by the direct bonding of the Al radiator plate as compared with 110°C of adhesive bonding. Walking speed of the in-pipe micro inspection machine which utilizes the direct bonding was successfully stabilized compared with the adhesive bonding.
Immunization in developing countries : its political and organizational determinants

The authors use cross-national social, political, economic, and institutional data to explain why some countries have stronger immunization programs than others, as measured by diphtheria-tetanus-pertussis (DTP) and measles vaccine coverage rates and the adoption of the hepatitis B vaccine. After reveiwing the existing literature on demand- and supply-side side factors that affect immunization programs, the authors find that the elements that most affect immunization programs in low- and middle-income countries involve broad changes in the global policy environment and contact with international agencies. Democracies tend to have lower coverage rates than autocracies, perhaps because bureaucratic elites have an affinity for immunization programs and are granted more autonomy in autocracies, althought this effect is not visible in low-income countries. The authors also find that the quality of a nation's institutions and its level of development are strongly related to immunization rate coverage and vaccine adoption, and that coverage rates are in general more a function of supply-side than demand effects. there is no evidence that epidemics or polio eradication campaigns affect immunization rates one way or another, or that average immunization rates increase following outbreaks of diphtheria, pertussis, or measles.
Iodine(V) reagents in organic synthesis. Part 3. New routes to heterocyclic compounds via o-iodoxybenzoic acid-mediated cyclizations: generality, scope, and mechanism.

The discovery and development of the o-iodoxybenzoic acid (IBX) reaction with certain unsaturated N-aryl amides (anilides) to form heterocycles are described. The application of the method to the synthesis of δ-lactams, cyclic urethanes, hydroxy amines, and amino sugars among other important building blocks and intermediates is detailed. In addition to the generality and scope of this cyclization reaction, this article describes a number of mechanistic investigations suggesting a single electron transfer from the anilide functionality to IBX and implicating a radical-based mechanism for the reaction.
Two results on equations of nilpotent orbits

We prove two results on the defining ideals of certain varieties of matrices. Let us fix two positive integers r, e. Let M(r) be the set of r x r matrices over a field K. We consider the closed subscheme of the nilpotent variety of M(r) over K defined by the conditions char_A(T)=T^r, A^e=0. We prove that when the characteristic of K is zero this scheme is reduced. Also for e=2 we prove that this scheme is reduced over a field K of arbitrary characteristic. These results were motivated by the questions of G. Pappas and M. Rapoport (compare their paper ''Local models in the ramified case I. The EL-case", math.AG/0006222) and give answers to some of their conjectures.
Generalized spacetimes defined by cubic forms and the minimal unitary realizations of their quasiconformal groups

We study the symmetries of generalized spacetimes and corresponding phase spaces defined by Jordan algebras of degree three. The generic Jordan family of formally real Jordan algebras of degree three describe extensions of the minkowskian spacetimes by an extra ``dilatonic'' coordinate, whose rotation, Lorentz and conformal groups are SO(d−1), SO(d−1,1) × SO(1,1) and SO(d,2) × SO(2,1), respectively. The generalized spacetimes described by simple Jordan algebras of degree three correspond to extensions of minkowskian spacetimes in the critical dimensions (d = 3,4,6,10) by a dilatonic and extra (2,4,8,16) commuting spinorial coordinates, respectively. Their rotation, Lorentz and conformal groups are those that occur in the first three rows of the Magic Square. The Freudenthal triple systems defined over these Jordan algebras describe conformally covariant phase spaces. Following hep-th/0008063, we give a unified geometric realization of the quasiconformal groups that act on their conformal phase spaces extended by an extra ``cocycle'' coordinate. For the generic Jordan family the quasiconformal groups are SO(d+2,4), whose minimal unitary realizations are given. The minimal unitary representations of the quasiconformal groups F4(4), E6(2), E7(−5) and E8(−24) of the simple Jordan family were given in our earlier work [10].
Nudging Privacy: The Behavioral Economics of Personal Information

Privacy decisions often involve balancing competing interests. As such, they're a natural field of study for economics. But traditional economic models have made overly restrictive assumptions about the stability and nature of individual privacy preferences. Approaches drawing on existing research in behavioral economics and psychology can offer complementary tools for understanding privacy decision making.
The Small Firm Effect and the Entrepreneurial Spawning of Scientists and Engineers

Scientists and engineers in small firms are far more likely than their large firm counterparts to enter entrepreneurship. We label this phenomenon the small firm effect and explore its origins. In particular, we identify four classes of explanations for the small firm effect---preference sorting, ability sorting, opportunity cost, and the possibility that workers in small firms develop entrepreneurial human capital---and examine the empirical evidence for each. We find that preference sorting does play a role in generating the small firm effect: small firms attract those with prior preferences for autonomy who are similarly drawn into entrepreneurship. Similarly, ability sorting plays a role: those who ultimately become entrepreneurs may be drawn first to small firms because they offer tighter pay-for-performance links and can subsequently improve their expected earnings by becoming entrepreneurs, or because the skills required for success in small firms are also valuable in entrepreneurship. Evidence suggests that although those with the very least to lose do enter entrepreneurship with greater frequency, opportunity cost has at best a modest role to play in explaining the small firm effect. Finally, we interpret evidence that prior experience in small firms predicts positive performance outcomes in the early stages of entrepreneurship as suggesting that workers in small firms may develop entrepreneurial human capital that makes them better entrepreneurs. This effect may be largest among those of high ability.
Efficient Syntheses of β-Cyanosugars Using Glycosyl Iodides Derived from Per-O-silylated Mono- and Disaccharides

Reported herein is a general method for the efficient syntheses of a variety of β-cyano glycosides through the activation of per-O-trimethylsilyl glycosides with TMSI to form α-glycosyl iodides, which undergo SN2-type displacement when treated with tetrabutylammonium cyanide. The cyanoglycosides were reduced under mild conditions using NaBH4 in the presence of catalytic CoCl2(H2O)6 in THF/H2O to give the corresponding aminomethyl glycosides.
Critical Temperature of the Deconfining Phase Transition in (2+1)d Georgi-Glashow Model

We find the temperature of the phase transition in the (2+1)d Georgi-Glashow model. The critical temperature is shown to depend on the gauge coupling and on the ratio of Higgs and gauge boson masses. In the BPS limit of light Higgs the previous result by Dunne, Kogan, Kovner, and Tekin is reproduced.
The Influence of Catalysts on Discharge and Charge Voltages of Rechargeable Li–Oxygen Batteries

This study revealed the strong influence of carbon, Au/C, and Pt/C catalysts on the charge and discharge voltages of rechargeable Li―O 2 batteries. Li―O 2 single-cell measurements showed that Au/C had the highest discharge activity, while Pt/C exhibited extraordinarily high charging activity.
Experiments in computer-aided graphic expression

This paper presents a series of graphic design experiments using an experimental colour graphic display system. Design principles and capabilities of the system are discussed from a graphic designer's point of view. The system allows a designer to choose freely among 128 different colours, various form modes, and collage capabilities, including image mixing. The designer need be neither a programmer nor one who understands the technical aspects of the system to use it creatively. Experimental results are shown visually here, some of which have been used as cover designs for IBM publications.
Discovering relative importance of skyline attributes

Querying databases with preferences is an important research problem. Among various approaches to querying with preferences, the skyline framework is one of the most popular. A well known deficiency of that framework is that all attributes are of the same importance in skyline preference relations. Consequently, the size of the results of skyline queries may grow exponentially with the number of skyline attributes. Here we propose the framework called p-skylines which enriches skylines with the notion of attribute importance. It turns out that incorporating relative attribute importance in skylines allows for reduction in the corresponding query result sizes. We propose an approach to discovering importance relationships of attributes, based on user-selected sets of superior and inferior examples. We show that the problem of checking the existence of and the problem of computing an optimal p-skyline preference relation covering a given set of examples are NP-complete and FNP-complete, respectively. However, we also show that a restricted version of the discovery problem -- using only superior examples to discover attribute importance -- can be solved efficiently in polynomial time. Our experiments show that the proposed importance discovery algorithm has high accuracy and good scalability.
Effects of Noise on Optimal Exercise Decisions: The Case of Risky Debt Secured by Renewable Lease Income

This paper considers the valuation and default exercise policy of risky coupon debt that is secured by a lease-encumbered noisy real asset. For parameter values used in our analysis, asset value noise is shown to reduce the value of waiting to default. Moreover, the borrower is shown to delay default exercise until the noisy signal of asset value is far into-the-money. This latter finding provides an information-based explanation for the apparent under-exercise of the mortgage default option that has been observed in the literature. An implication of this finding is that, if the claimholder recognizes that noise exists, but the empiricist—who is trying to compare observed exercise policy with that predicted by a noiseless model of asset prices—does not, a “sub-optimal” exercise policy may be inferred when in fact the policy is rational given the information available. This explanation is consistent with evidence from mortgage default studies as to why the observed default exercise boundary is lower than that predicted by standard theoretical option-based models.
Network of Perceptions

The role of perception in conscious behavior and decision-making is examined. The effect of spatial and temporal stochasticity in the acquisition of beliefs is discussed. The idea of an agent as a locally strongly coupled group of states leads to the creation of energy minima in an interaction potential landscape. The interaction of such agent states and environment states acting at different levels of complexity and scale, subject to stochastically expressed interaction interfaces, may lead to asymmetry in perceptions. Agents possessing different perception related beliefs are then connected in a social network.
Debt Relief and Debtor Outcomes: Measuring the Effects of Consumer Bankruptcy Protection

Consumer bankruptcy is one of the largest social insurance programs in the United States, but little is known about its impact on debtors. We use 500,000 bankruptcy filings matched to administrative tax and foreclosure data to estimate the impact of Chapter 13 bankruptcy protection on subsequent outcomes. Exploiting the random assignment of bankruptcy filings to judges, we find that Chapter 13 protection increases annual earnings by $5,562, decreases five-year mortality by 1.2 percentage points, and decreases five-year foreclosure rates by 19.1 percentage points. These results come primarily from the deterioration of outcomes among dismissed filers, not gains by granted filers. (JEL D14, I12, J22, J31, K35)
Wentzel-Bardeen singularity in coupled Luttinger liquids: transport properties

Abstract The recent progress on 1D interacting electrons systems and their applications to study the transport properties of quasi one-dimensional wires is reviewed. We focus on strongly correlated electrons coupled to low energy acoustic phonons in one dimension. The exponents of various response functions are calculated, and their striking sensitivity to the Wentzel-Bardeen singularity is discussed. For the Hubbard model coupled to phonons the equivalent of a phase diagram is established. By increasing the filling factor towards half filling the WB singularity is approached. This in turn suppresses antiferromagnetic fluctuations and drives the system towards the superconducting regime, via a new intermediate (metallic) phase. The implications of this phenomenon on the transport properties of an ideal wire as well as the properties of a wire with weak or strong scattering are analyzed in a perturbative renormalization group calculation. This allows to recover the three regimes predicted from the divergence criteria of the response functions.
CMB POLARIZATION: THE NEXT DECADE

I review the exciting science that awaits cosmologists in precision measurements of the cosmic microwave background radiation, particularly its polarization. The conclusions of the Interagency Taskforce ("Weiss Panel") will also be presented. I conclude with an update based primarily on the new WMAP results from their three-year analysis.
Lithium Depletion in Fully Convective Pre-Main-Sequence Stars

We present an analytic calculation of the thermonuclear depletion of lithium in contracting, fully convective, pre-main-sequence stars of mass M 0.5 M☉. Previous numerical work relies on still uncertain physics (atmospheric opacities and convection, in particular) to calculate the effective temperature as a unique function of stellar mass. We assume that the star's effective temperature, Teff, is fixed during Hayashi contraction and allow its actual value to be a free parameter constrained by observation. Using this approximation, we compute lithium burning analytically and explore the dependence of lithium depletion on Teff, M, and composition. Our calculations yield the radius, age, and luminosity of a pre-main-sequence star as a function of lithium depletion. This allows for more direct comparisons with observations of lithium-depleted stars. Our results agree with those numerical calculations that explicitly determine stellar structure during Hayashi contraction. In agreement with Basri, Marcy, & Graham, we show that the absence of lithium in the Pleiades star HHJ 3 implies that it is older than 100 Myr. We also suggest a generalized method for dating Galactic clusters younger than 100 Myr (i.e., those with contracting stars of M 0.08 M☉) and for constraining the masses of lithium-depleted stars.
Shadowing of the Nascent Jet in NGC 4261 by a Line-emitting Supersonic Accretion Disk

NGC 4261 (3C 270) is a low-luminosity radio galaxy with two symmetric kiloparsec-scale jets. Earlier Hubble Space Telescope observations indicated the presence of a 100 pc scale disk of cool dust and gas surrounding a central, supermassive (~4.9 × 108 M☉) black hole. The recent detection of free-free radio absorption by a small, geometrically thin disk, combined with earlier studies of the disk's large-scale properties, provides the strictest constraints to date on the nature of the accretion process in this system. We show here that a supersonic disk, illuminated by the active galactic nucleus (AGN), not only can account for the observed radio shadowing but can also produce the optical broad lines emitted from this region. At large radii, the gas is optically thin because the ram pressure due to turbulence is much larger than the thermal pressure of the gas. At smaller radii, but beyond a critical radius rc, line cooling dominates over gravitational dissipation and the gas is effectively cooled down to temperatures below 104 K. Within rc, however, heating due to the release of gravitational energy overwhelms line cooling and the gas falls onto the unstable portion of the cooling curve. Because cooling is quite inefficient under these conditions, the plasma is heated very quickly to a temperature close to its virial value as it falls toward the central engine. Thermal pressure of the gas dominates the turbulent ram pressure at a radius ~ rc, below which the flow probably becomes advection dominated. The disk is optically thin to UV and X-ray radiation within rc, so the ionizing radiation from the AGN is preferentially absorbed near rc, affecting the disk structure significantly. To include the ensuing photoionization effect, we have used the algorithm CLOUDY with additional heating introduced by gravitational dissipation to calculate the temperature profile and line emission from the disk in a self-consistent manner. The results of our model calculation are consistent with current multiwavelength observations of the disk in this source.
An overview of the metabolic functions of osteocalcin

A recent unexpected development of bone biology is that bone is an endocrine organ contributing to the regulation of a number of physiological processes. One of the functions regulated by bone through osteocalcin, an osteoblast specific hormone, is glucose homeostasis. In this overview, we explain the rationale why we hypothesized that there should be a coordinated endocrine regulation between bone mass and energy metabolism. We then review the experiments that identified the endocrine function of osteocalcin and the cell biology events that allow osteocalcin to become a hormone. We also demonstrate the importance of this regulation to understand whole-body glucose homeostasis in the physiological state and in pathological conditions. Lastly we discuss the epidemiological and genetic evidence demonstrating that this function of osteocalcin is conserved in humans.
Palladium-catalyzed one-pot synthesis of 2-alkyl-2-arylcyanoacetates.

A one-pot procedure for the synthesis of 2-alkyl-2-arylcyanoacetates based on a Pd(OAc)2/DPPF (DPPF = 1,1‘-diphenylphosphino ferreocene)-catalyzed enolate arylation followed by in situ alkylation has been developed. This procedure tolerates a diverse range of aryl and heteroaryl bromides, and provides a rapid entry to a variety of 2-alkyl-2-arylcyanoacetates in good to excellent yield.
Text (Oral) Reading Fluency as a Construct in Reading Development: An Investigation of Its Mediating Role for Children From Grades 1 to 4

In the present study we investigated a developmentally changing role of text reading fluency in mediating the relations of word reading fluency and listening comprehension to reading comprehension. We addressed this question by using longitudinal data from Grades 1 to 4, and employing structural equation models. Results showed that the role of text reading fluency changes over time as children's reading proficiency develops. In the beginning phase of reading development (Grade 1), text reading fluency was not independently related to reading comprehension over and above word reading fluency and listening comprehension. In Grades 2 to 4, however, text reading fluency completely mediated the relation between word reading fluency and reading comprehension whereas it partially mediated the relation between listening comprehension and reading comprehension. These results suggest that text reading fluency is a dissociable construct that plays a developmentally changing role in reading acquisition.
Direct conversion of esters to secondary amides using Tin(II) reagents

Abstract We have developed two new procedures for the direct conversion of esters to secondary amides. In our first procedure, secondary amides can be prepared in 83–98% yield starting from glycol esters. Addition of Sn[N(TMS) 2 ] 2 and a primary amine to the glycol ester generates an intermediate tin(II) alkoxy amide, which delivers the amino group intramolecularly to give the amide. A second general procedure for the preparation of secondary amides start with methyl esters. Treatment of methyl ester with a tin reagent derived from Sn[N(TMS) 2 ] 2 , Me 2 NCH 2 CH 2 OH, and a primary amides in 87–98% yield.
SEARCH FOR A NEUTRAL MESON OF ZERO I-SPIN

A search has been made for a neutral meson of zero I-spin by means of the reaction d+d→4He+π00. No evidence was found for the existence of the π00 in the mass range zero to 1.8 times the π± mass. The upper limit of the cross section was 7·10−32 cm2 for π00⋍π± mass. The reaction was studied by using 460 MeV deuterons from the Berkeley 184 in. cyclotron and a liquid deuterium target.α-particles produced at 0° in the laboratory system were selected by momentum analysis and by a counter telescope which measured time of flight, dE/dx, and differential range. The experiment may also set a limit on the validity of charge independence.
Neurochemical correlates of synaptically active amino acids.

Publisher Summary This chapter discusses the neurochemical correlates of synaptically active amino acids. An abundance of evidence indicates that the high affinity uptake systems for glycine and glutamic and aspartic acids label unique populations of nerve terminals in which these substances may serve a neurotransmitter role. The initial experiments on amino acid uptake employed relatively crude homogenate systems which can be prepared more rapidly than purified synaptosomes. It is found that these preparations cannot be washed as they contain enough endogenous concentrations of the amino acids that one cannot reliably study the uptake of lower than 10 μM concentration of radioactive amino acid. The serotonin precursor, L-tryptophan, apparently is accumulated into rat synaptosomes by a high-affinity system, and using purified synaptosomes others reported high affinity accumulation of leucine into the cerebral cortex. Accordingly, one can reexamine the accumulation of numerous amino acids by purified preparations of synaptosomes, focusing on concentrations between 1 and 10 μM. For all amino acids studied in the cerebral cortex, with the exception of glycine, one can demonstrate high affinity synaptosomal uptake.
Asymptotic aspects of Schreier graphs and Hanoi Towers groups

Abstract We present relations between growth, growth of diameters and the rate of vanishing of the spectral gap in Schreier graphs of automaton groups. In particular, we introduce a series of examples, called Hanoi Towers groups since they model the well known Hanoi Towers Problem, that illustrate some of the possible types of behavior. To cite this article: R. Grigorchuk, Z. Sunik´, C. R. Acad. Sci. Paris, Ser. I 342 (2006).
Bounded rank subgroups of Coxeter groups, Artin groups and one-relator groups with torsion

We obtain a number of results regarding the freeness of subgroups of Coxeter groups, Artin groups and one-relator groups with torsion. In the case of Coxeter groups, we also obtain results on quasiconvexity and subgroup separability.
Feedback control of growth rate and surface roughness in thin film growth

A method for multivariable feedback control of surface roughness and growth rate in thin film growth using kinetic Monte-Carlo (MC) models is proposed. The method is applied to the process of thin film growth in a stagnation flow geometry including atom adsorption, desorption, and surface migration as the three processes that shape film microstructure and determine film growth rate. A multiscale model involving coupled partial differential equations to model the gas phase and a kinetic MC simulator, based on a large lattice, for the modeling of film growth, is used to simulate the process. A roughness and growth rate estimator constructed allowed computing estimates of the surface roughness and growth rate at a time-scale comparable to the real-time evolution of the process. The estimator involves kinetic MC simulators based on small lattice models, adaptive filters used to reduce stochastic fluctuations of the outputs of the small lattice MC simulator outputs, and measurement error compensators used to reduce the errors between the estimates and measurements. The interactions between the inputs (substrate temperature and inlet precursor mole fraction) and outputs (growth rate and surface roughness) in the closed-loop system are studied and found to be significant. A multivariable feedback controller, which uses the state estimator and explicitly compensates for the effect of input/output interactions, is designed to simultaneously regulate the growth rate and surface roughness by manipulating substrate temperature and inlet precursor mole fraction. Application of the estimator/controller structure to the multiscale process model demonstrates successful regulation of the surface roughness and growth rate to the desired set point values. This approach is shown to be superior to control of the growth rate and surface roughness using two independent feedback control loops.
A convenient preparation of O-alkyl selenoesters from esters

Abstract A new methodology is described for the synthesis of O-alkyl selenoesters from esters. The ester is converted to the silyl ketene acetal with LDA and Me 3 SiCl, which is then treated with H 2 Se generated in situ from aluminum selenide and dilute HCl.
Remote measurements of ion temperatures in the terrestrial magnetotail

[1] Time-resolved remote ion temperature measurements of the magnetosphere from 10 R E to ―60 R E are presented for the first 48 h of the storm of 4―7 October 2000. Ion temperatures are calculated from Maxwellian fits to data from the Medium Energetic Neutral Atom instrument aboard the Imager for Magnetopause-to-Aurora Global Exploration spacecraft. The calculated ion temperatures in the magnetotail are consistent with in situ measurements from multiple geosynchronous spacecraft and Geotail at x = -9 R E . The measurements indicate two separate instances of an earthward propagating increase in ion temperature during the storm. Ion heating is observed coincident with substorm injections at 0600 UT and 1720 UT on 4 October. At -12 R E , the remotely measured ion temperatures are consistent with predictions of a solar wind velocity correlation equation only when the solar wind-magnetospheric coupling is strong. At other times, the measured ion temperature is 2-3 times larger than the predicted value.
Generation, rearrangements and some synthetic uses of bishomoallyllithiums

Abstract A general preparative method for bishomoallyllithiums consists of reductive lithiation by 4,4′-di-tert-butylbiphenylide (LDBB) of bishomoallyl phenyl sulfides, which can be prepared by (1) thioacetalization of γ, δ-unsaturated ketones followed by replacing one of the phenylthio groups with an alkyl group or a hydrogen or (2) Wittig or Peterson olefination of γ (phenylthio)ketones prepared in turn by conjugate addition of phenylthiomethyl cuprates to enones in the presence of chlorotrimethylsilane. Several of the secondary and tertiary bishomoallyllithiums rearrange to primary bishomoallyllithiums via cyclobutylcarbinyllithium intermediates. An oxyanionic group on a carbon atom adjacent to the lithium-bearing carbon atom has a remarkable accelerating effect on the ring closure to a 4-membered ring. Formylation of some bishomoallyllithiums affords the precursors of type-II intramolecular ene reactions, which generate six membered ring compounds when subjected to Lewis acid-catalyzed cyclization.
CBIR: from low-level features to high-level semantics

The performance of a content-based image retrieval (CBIR) system is inherently constrained by the features adopted to represent the images in the database. Use of low-level features can not give satisfactory retrieval results in many cases; especially when the high-level concepts in the user's mind is not easily expressible in terms of the low-level features. Therefore whenever possible, textual annotations shall be added or extracted and/or processed to improve the retrieval performance. In this paper a hybrid image retrieval system is presented to provide the user with the flexibility of using both the high-level semantic concept/keywords as well as low-level feature content in the retrieval process. The emphasis is put on a statistical algorithm for semantic grouping in the concept space through relevance feedback in the image space. Under this framework, the system can also incrementally learn the user's search habit/preference in terms of semantic relations among concepts; and uses this information to improve the performance of subsequent retrieval tasks. This algorithm can eliminate the need for a stand-alone thesaurus, which may be too large in size and contain too much redundant information to be of practical use. Simulated experiments are designed to test the effectiveness of the algorithm. An intelligent dialogue system, to which this algorithm can be a part of the knowledge acquisition module, is also described as a front end for the CBIR system.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
QUADRISECANTS OF KNOTS AND LINKS

We show that every non-trivial tame knot or link in ℝ3 has a quadrisecant, i.e. four collinear points. The quadrisecant must be topologically non-trivial in a precise sense. As an application, we show that a nonsingular, algebraic surface in ℝ3 which is a knotted torus must have degree at least eight.
New Evidence for Early Silk in the Indus Civilization

Silk is an important economic fibre, and is generally considered to have been the exclusive cultural heritage of China. Silk weaving is evident from the Shang period c. 1600–1045 bc, though the earliest evidence for silk textiles in ancient China may date to as much as a millennium earlier. Recent microscopic analysis of archaeological thread fragments found inside copper-alloy ornaments from Harappa and steatite beads from Chanhu-daro, two important Indus sites, have yielded silk fibres, dating to c. 2450–2000 bc. This study offers the earliest evidence in the world for any silk outside China, and is roughly contemporaneous with the earliest Chinese evidence for silk. This important new finding brings into question the traditional historical notion of sericulture as being an exclusively Chinese invention.
Impact of physical principles at very high energy scales on the superparticle mass spectrum

We survey a variety of proposals for new physics at high scales that serve to relate the multitude of soft supersymmetry breaking parameters of the MSSM. We focus on models where the new physics results in non-universal soft parameters, in sharp contrast with the usually assumed mSUGRA framework. These include (i) SU(5) and SO(10) grand unified (GUT) models, (ii) the MSSM plus a right-handed neutrino, (iii) models with effective supersymmetry, (iv) models with anomaly-mediated SUSY breaking and gaugino mediated SUSY breaking, (v) models with non-universal soft terms due to string dynamics, and (vi) models based on M-theory. We outline the physics behind these models, point out some distinctive features of the weak-scale sparticle spectrum, and allude to implications for collider experiments. To facilitate future studies, for each of these scenarios, we describe how collider events can be generated using the program ISAJET. Our hope is that detailed studies of a variety of alternatives will help point to the physics underlying SUSY breaking and how this is mediated to the observable sector, once sparticles are discovered and their properties measured.
A review of resonance response in large, horizontal-axis wind turbines

Abstract Field operation of the Mod-0 and Mod-1 wind turbines has provided valuable information concerning resonance response in large, two-bladed, horizontal-axis wind turbines. Operational experience has shown that 1/rev excitation exists in the drive train, high aerodynamic damping prevents resonance response of the blade flatwise modes, and teetering the hub substantially reduces the chordwise blade response to odd harmonic excitation. These results can be used by the designer as a guide to system frequency placement. In addition, it has been found that present analytical techniques can accurately predict wind turbine natural frequencies.
Crustal‐scale fluid transport: Magnitude and mechanisms

Fluids in the crust of the Earth play an important role in the geochemical and geophysical structure of the crust. They are responsible for a multitude of chemical/rock reactions and couple directly with geophysical processes and the geophysical imaging of the crust. The known depth of significant fluid reaction/transport has been increasing in recent years with the detailed study of drilled and exhumed solid phase samples. From both isotopic and chemical evidence, it is clear that meteoric fluids can penetrate at least 10 kilometers into the crust of the Earth (fluids have also been sampled directly from a depth of 12 km in the Kola Peninsula Drillhole) and the horizontal scale of fluid transport is now known to extend 100's of kilometers. Furthermore, as the kinetics and reaction dynamics (rather than simple equilibrium)are included to explain these observations, estimates of the fluid volumes (expressed as a water/rock ratio)required to emplace these fluid derived rock suites and deposits have increased steadily.
Families of Spectral Sets for Bernoulli Convolutions

We study the harmonic analysis of Bernoulli measures μ λ , a one-parameter family of compactly supported Borel probability measures on the real line. The parameter λ is a fixed number in the open interval (0,1). The measures μ λ may be understood in any one of the following three equivalent ways: as infinite convolution measures of a two-point probability distribution; as the distribution of a random power series; or as an iterated function system (IFS) equilibrium measure determined by the two transformations λ(x±1). For a given λ, we consider the harmonic analysis in the sense of Fourier series in the Hilbert space L 2(μ λ ). For L 2(μ λ ) to have infinite families of orthogonal complex exponential functions e 2πis(⋅), it is known that λ must be a rational number of the form $\frac{m}{2n}$ , where m is odd. We show that $L^{2}(\mu_{\frac{1}{2n}})$ has a variety of Fourier bases; i.e. orthonormal bases of exponential functions. For some other rational values of λ, we exhibit maximal Fourier families that are not orthonormal bases.
Management Fashion: Lifecycles, Triggers, and Collective Learning Processes:

This theory-development case study of the quality circle management fashion focuses on three features of management-knowledge entrepreneurs' discourse promoting or discrediting such fashions: its lifecycle, forces triggering stages in its lifecycle, and the type of collective learning it fostered. Results suggest, first, that variability in when different types of knowledge entrepreneurs begin, continue, and stop promoting fashions explains variability in their lifecycles; second, that historically unique conjunctions of forces, endogenous and exogenous to the management-fashion market, trigger and shape management fashions; and third, that emotionally charged, enthusiastic, and unreasoned discourse characterizes the upswings of management fashion waves, whereas more reasoned, unemotional, and qualified discourse characterizes their downswings, evidencing a pattern of superstitious collective learning.
Acidity of unsupported and silica-supported vanadia, molybdena, and titania as studied by pyridine adsorption

The acidic properties of unsupported titania, vanadia, and molybdena, and the corresponding silica-supported metal oxides were studied. The number of acid sites was investigated by thermogravimetry of adsorbed pyridine. The types of acid sites were examined by infrared spectroscopy of adsorbed pyridine. Both Lewis and Bronsted acid sites were present on the surfaces of V2O5 and MoO3, while Lewis acid sites were found exclusively for TiO2. When supported on silica, vanadia and molybdena species showed a greater number of acid sites than the corresponding unsupported oxides. The oxidized surfaces of these materials possessed both Lewis and Bronsted acid sites. In contrast, Lewis sites predominated on the surfaces of the reduced samples. Silica-supported titania showed strong Lewis acidity, analogous to unsupported titania. The addition of water vapor was observed to generate Bronsted acid sites for the oxidized forms of silica-supported titania, vanadia, and molybdena. This behavior was not observed for the reduced forms of these materials. Pauling's electrostatic bond strength rules are shown to be useful to predict whether Bronsted acid sites exist on the surfaces of metal oxides.
Statistical Mechanics of Horizontal Gene Transfer in Evolutionary Ecology

The biological world, especially its majority microbial component, is strongly interacting and may be dominated by collective effects. In this review, we provide a brief introduction for statistical physicists of the way in which living cells communicate genetically through transferred genes, as well as the ways in which they can reorganize their genomes in response to environmental pressure. We discuss how genome evolution can be thought of as related to the physical phenomenon of annealing, and describe the sense in which genomes can be said to exhibit an analogue of information entropy. As a direct application of these ideas, we analyze the variation with ocean depth of transposons in marine microbial genomes, predicting trends that are consistent with recent observations using metagenomic surveys.
Techniques and applications of computation slicing

Writing correct distributed programs is hard. In spite of extensive testing and debugging, software faults persist even in commercial grade software. Many distributed systems should be able to operate properly even in the presence of software faults. Monitoring the execution of a distributed system, and, on detecting a fault, initiating the appropriate corrective action is an important way to tolerate such faults. This gives rise to the predicate detection problem which requires finding whether there exists a consistent cut of a given computation that satisfies a given global predicate.Detecting a predicate in a computation is, however, an NP-complete problem in general. In order to ameliorate the associated combinatorial explosion problem, we introduce the notion of computation slice. Formally, the slice of a compuation with respect to a predicate is a (sub)computation with the least number of consistent cuts that contains all consistent cuts of the computation satisfying the predicate. Intuitively, slice is a concise representation of those consistent cuts of a computation that satisfy a certain condition. To detect a predicate, rather than searching the state-space of the computation, it is much more efficient to search the state-space of the slice.We prove that the slice of a computation is uniquely defined for all predicates. We also present efficient algorithms for computing the slice for several useful classes of predicates. For an arbitrary predicate. we establish that the problem of computing the slice is NP-complete in general. Nonetheless, for such a predicate, we develop an efficient heuristic algorithm for computing an approximate slice. Our experimental results demonstrate that slicing can lead to an exponential improvement over existing techniques for predicate detection in terms of time and space.
MEASUREMENTS OF MAGNETIC FIELD STRENGTHS IN THE VICINITY OF ORION

We have measured the line-of-sight magnetic field in two regions associated with the Orion Nebula. One region is the large H I cloud which envelops the ionized and molecular clouds; the field strength is 10 microgauss. The other is the large CO cloud just south of the Orion Nebula discovered by Kutner, Tucker, and Chin; the field strength here is also 10 microgauss. These results are discussed using the virial theorem. In the H I cloud, gravity appears to be weaker than the kinetic and magnetic forces, making this cloud unstable to expansion. In the CO cloud, gravity and the kinetic forces balance, and the magnetic field may be important in supporting the cloud.
Ab initio study of BaTiO 3 and PbTiO 3 surfaces in external electric fields

For the ferroelectric perovskite compounds ${\mathrm{BaTiO}}_{3}$ and ${\mathrm{PbTiO}}_{3},$ we have studied the effects of external electric fields on the structural properties of the (001) surfaces. The field-induced changes in the surface interlayer spacings and bucklings have been calculated using a first-principles ultrasoft-pseudopotential approach, and the change of the polarization and the ferroelectric distortions in the surface layers have been obtained. The surfaces are represented by periodically repeated slabs, and an external dipole layer is included in the vacuum region of the supercells to control the electric field normal to the surfaces. The influence of the electrical boundary conditions on the ferroelectric properties of the slabs is discussed. In the case of a vanishing internal electric field, our study indicates that even very thin slabs can show a ferroelectric instability.
Amplitude analysis of elastic p − p scattering at 6 GeV/ c at all t ' s

The extensive set of polarization data obtained at the Argonne Zero Gradient Synchro- p tron for elastic proton-proton scattering at 6 GeV/c at a full set of values of t is used to determine the five complex reaction amplitudes, using the optimal formalism. The determination is easiest in the transversity formalism, and from that the ''planar'' amplitudes (including the helicity amplitudes) are obtained. A complete determination is made at 20 different values of t, from -0.1 to -1.0 (GeV/c)/sup 2/, using data interpolated in t. In addition, a less complete set of data permits the determination of the five magnitudes (but not of the four phases) in the range from t = -1.0 to t = -2.0 (GeV/c)/sup 2/. The magnitudes of the five amplitudes can be obtained without any ambiguity, but for the four relative phases several distinct solutions exist, one of which is selected on the basis of continuity in t and minimum chi/sup 2/. There continues to be evidence that in the planar system in which the orientation axes are 90/sup 0/ from the helicity axes, all amplitudes tend to be either pure real or pure imaginary.