cssi/SciSciGPT-SciSciNet huggingface dataset:
The first successful base-promoted isomerization of propargyl amides to chiral ynamides. Applications in ring-closing metathesis of ene-ynamides and tandem RCM of diene-ynamides.

A highly useful sequence of reactions is described here. These reactions consist of the first successful base-induced isomerizations of propargyl amides to chiral ynamides, applications of these novel ynamides in ring-closure metathesis leading to chiral 2-amidodienes useful for Diels−Alder cycloadditions, and the first successful tandem RCM of diene−ynamides.
Distributed scheduling of resources on interconnection networks

In this paper, we have studied the distributed scheduling of resources on interconnection networks. The resource scheduling problem is different from the conventional address mapping problem on interconnection networks because a request is not directed towards a particular destination address but to any one of a pool of destination addresses for free resources. To design an algorithm with the minimum transfer of control signals, priority is associated with the scheduling of multiple requests. This is illustrated by the distributed cross-bar switch which has one signal line in each direction of a switch node. For complete asynchronous operation, more signal lines are needed. This is illustrated by the distributed Omega and binary n-cube networks. Each exchange box in the network operates independently to resolve conflicts. The performance of the distributed scheduling algorithm for the Omega and cube networks is compared against the optimal centralized scheduling algorithm which has about 1% average blocking probability. The performance degradation is less than 20% in all cases. The theory of the design can be applied to other interconnection networks.
A Structure Theorem for Poorly Anticoncentrated Gaussian Chaoses and Applications to the Study of Polynomial Threshold Functions

We prove a structural result for degree-$d$ polynomials. In particular, we show that any degree-$d$ polynomial, $p$ can be approximated by another polynomial, $p_0$, which can be decomposed as some function of polynomials $q_1, \ldots, q_m$ with $q_i$ normalized and $m=O_d(1)$, so that if $X$ is a Gaussian random variable, the probability distribution on $(q_1(X), \ldots, q_m(X))$ does not have too much mass in any small box. Using this result, we prove improved versions of a number of results about polynomial threshold functions, including producing better pseudorandom generators, obtaining a better invariance principle, and proving improved bounds on noise sensitivity.
Infinite Dimensional Parametric Optimal Control Problems

In this paper we study parametric optimal control problems monitored by nonlinear evolution equations. The parameter appears in all the data, including the nonlinear operator. First we show that for every value of the parameter, the optimal control problem has a solution. Then we study how these solutions as well as the value of the problem respond to changes in the parameter. Finally, we work out in detail two examples of nonlinear parabolic optimal control systems.
The measurement of the light deflection from jupiter: experimental results

We have determined the relativistic light deflection of the quasar J0842+1835 as Jupiter passed within 37 on 2002 September 8, by measuring the time delay using the Very Long Baseline Array (VLBA) and Effelsberg radio telescopes at 8.4 GHz. At closest approach, general relativity (GR) predicts a radial (static) deflection of 1190 μas and a tangential (retarded) deflection in the direction of Jupiter's motion of 51 μas. Our experiment achieved an rms position error of ≤10 μas and measured this retarded deflection to be 0.98 ± 0.19 (rms error) times that predicted by GR. The increased positional accuracy for this VLBI phase-referencing experiment was achieved by using two calibrator sources. Comments on the interpretation of this experiment are given.
Stability and refrigeration of magnet cryosystems near 1.8 K using the thermomechanical effect

Superconducting magnets may exhibit a significantly increased critical surface when the operating temperature is lowered. It is also known that the stability associated with superconductor-coolant interaction is enhanced in superfluid Helium-4 (He II), provided the coolant ducts have been optimized. The use of He II has been promoted in several large systems. The authors have investigated magnet cryosystem options which utilize the thermomechanical effect (fountain effect) of He II and its inverse, the mechano-caloric effect, for refrigeration (called vortex refrigeration). Examples are presented for simplified thermodynamic state changes of cycle operation. Topics covered include heat leak utilization for the He II range and the quantification of vortex refrigeration. >
Data acquisition in multiple-sink sensor networks

Scalable, energy-efficient data acquisition in large sensor network deployments such as habitat monitoring is an research important problem. In several papers [1, 2], sensor networks have been modeled as having a single sink (or base-station) that acts as the data recipient for a large number of sensors (data sources) deployed over a sensor field. The sensor network might use simple querying and data collection trees for hop-by-hop query dissemination and routing of sensor responses [1] back towards the sink. Since sensors are energy-constrained devices, we wish to minimize communication energy expenditure of these sensors.
A model of coronal holes

It has been noted that coronal holes appear to be associated with regions of diverging magnetic field in the corona. We set out to test the hypothesis that coronal holes may be caused by an increased flow of energy into the solar wind resulting directly from this diverging magnetic field pattern. Simple models were devised to approximate the energy flow down into the transition region and up into the solar wind as a function of the temperature, density, and rate of field line divergence in the corona. By assuming the rate of mechanical energy influx into the corona to be constant, it was then possible to solve numerically for the coronal temperature and density as a function of the rate of field line divergence. The results of these calculations demonstrate that a diverging field pattern can, indeed, bring about reductions in the temperature and density at the base of the corona comparable to those observed in coronal holes.
Unreliable sensor grids: coverage, connectivity and diameter

We consider an unreliable wireless sensor grid network with n nodes placed in a square of unit area. We are interested in the coverage of the region and the connectivity of the network. We first show that the necessary and sufficient conditions for the random grid network to cover the unit square region as well as ensure that the active nodes are connected are of the form p(n)r^2(n)~log(n)/n, where r(n) is the transmission radius of each node and p(n) is the probability that a node is ''active'' (not failed). This result indicates that, when n is large, even if each node is highly unreliable and the transmission power is small, we can still maintain connectivity with coverage. We also show that the diameter of the random grid (i.e., the maximum number of hops required to travel from any active node to another) is of the order n/log(n). Finally, we derive a sufficient condition for connectivity of the active nodes (without necessarily having coverage). If the node success probability p(n) is small enough, we show that connectivity does not imply coverage.
Evolution of flux-conserving tokamak equilibria with preprogrammed cross sections

Abstract The evolution of MHD equilibria toward high β is modeled by magnetic flux conservation with a given q ( ψ ) and by single fluid particle and energy balances which determine p ( ψ , t ). These one-dimensional flux surface averaged equations, written with magnetic flux ψ as the independent variable, are coupled to the two-dimensional MHD equilibrium equation through ψ, p ( ψ , t ), and q ( ψ ). The location and evolution of the plasma cross section boundary are precisely specified through the use of a fixed boundary equilibrium technique. In moving boundary studies (e.g., plasma compression) the resulting system of equations is advanced in time from an initial state by a procedure which utilizes two nested predictor-corrector loops together with an implicit time-stepping technique. The inner predictor-corrector loop advances the transport equations subject to a given equilibrium configuration while the outer loop evolves the equilibrium. For fixed plasma boundaries this procedure is modified for greater computational speed. These techniques provide satisfactory numerical convergence together with complete consistency between the coupled one-dimensional system of equations and the two-dimensional equilibrium. This method can be applied to the study of equilibrium evolution involving dramatic changes of plasma position, shape, and profiles while prescribing the evolution of the plasma boundary. As such, it can serve as a useful tool in the design of poloidal field systems or as a source of equilibria in high-β MHD stability studies. As an example, the compressional scaling laws of Furth and Yoshikawa are found to be modified for small aspect ratio.
A Reinterpretation of Relativity

THE theory of relativity is an undeniable achievement in physics and is a logical development of the theory of measurement; but it does not have the significance for the universe which is usually ascribed to it. Real time is not fused with space, and absolute simultaneity does have a definite and definable meaning.
Closed Loop Navigation and Guidance for Gravity Probe B Orbit Insertion

This paper addresses the problem of guiding the Gravity Probe B (GP-B) spacecraft from its location after initial insertion to a very precise low earth orbit. Specifically, the satellite orbit is required to be circular to within 0.001 eccentricity, polar to within 0.001 deg inclination, and aligned with the direction of the star Rigel to within 0.001 deg. Navigation data supplied by an on-board GPS receiver is used as feedback to a control algorithm designed to minimize the time to achieve the desired orbit. Translational control is provided by the proportional helium thrusters, which are used for drag-free and attitude control during the remainder of the science mission. Simulations of the guidance system are presented which give an indication of performance characteristics for several types of orbit injection errors. This research is the first reported effort to use GPS as a sensor for a closed loop space guidance system.
Deep-Subwavelength Focusing and Steering of Light in an Aperiodic Metallic Waveguide Array

We consider an aperiodic array of coupled metallic waveguides with varying subwavelength widths. For an incident plane wave, we numerically demonstrate that a focus of as small as one-hundredth of a wavelength can be achieved for a focal distance that is much longer than the wavelength. Moreover, the focusing behavior can be controlled by changing either the incident wavelength or the angle of incidence, thus providing the capability of nanoscale beam steering. We show that the behavior of such subwavelength focusing can be understood using Hamiltonian optics.
Well-posedness of the free-surface incompressible Euler equations with or without surface tension

We provide a new method for treating free boundary problems in perfect fluids, and prove local-in-time well-posedness in Sobolev spaces for the free-surface incompressible 3D Euler equations with or without surface tension for arbitrary initial data, and without any irrotationality assumption on the fluid. This is a free boundary problem for the motion of an incompressible perfect liquid in vacuum, wherein the motion of the fluid interacts with the motion of the free-surface at highest-order
A topological extension of general relativity

A set of algebraic equations for the topological properties of space-time is derived, and used to extend general relativity into the Planck domain. A unique basis set of three-dimensional prime manifolds is constructed which consists of S3, S1 × S2, and T3. The action of a loop algebra on these prime manifolds yields topological invariants which constrain the dynamics of the four-dimensional space-time manifold. An extended formulation of Mach's principle and Einstein's equivalence of inertial and gravitational mass is proposed which leads to the correct classical limit of the theory. It is found that the vacuum possess four topological degrees of freedom corresponding to a lattice of three-tori. This structure for the quantum foam naturally leads to gauge groups O(n) and SU(n) for the fields, a boundary condition for the universe, and an initial state characterized by local thermal equilibrium. The current observational estimate of the cosmological constant is reproduced without fine-tuning and found to be proportional to the number of macroscopic black holes. The black hole entropy follows immediately from the theory and the quantum corrections to its Schwarzschild horizon are computed.
Social choice with infinite populations: construction of a rule and impossibility results

We provide a simple construction of social choice rules for economies with infinite populations. The rules are continuous, Pareto and non-dictatorial; they are constructed as limits of individual preferences when the limit exists, and otherwise as adequate generalizations. This contrasts with the impossibility results of Arrow (1951) and Chichilnisky (1980), which are valid on economies with finitely many individuals. Our social choice rules are, however, limits of dictatorial rules. This paper was written in 1979.
Arylation of Aldehyde Homoenolates with Aryl Bromides

A mild palladium catalyzed coupling of reactive aldehyde homoenolates with aryl bromides is described. Aldehyde homoenolates are generated by ring opening of cyclopropanols via a C–C cleavage step. The coupling generates aldehyde products at room temperature in 59–93% yield.
Neurodevelopmental outcomes of extremely low birth weight infants exposed prenatally to dexamethasone versus betamethasone

OBJECTIVE. We compared the development of adverse neurodevelopmental outcomes at corrected ages of 18 to 22 months for extremely low birth weight infants exposed prenatally to dexamethasone, betamethasone, or no steroid. METHODS. Study infants were extremely low birth weight (401–1000 g) infants who were in the care of National Institute of Child Health and Human Development Neonatal Research Network centers between January 1, 2002, and April 30, 2003; they were assessed neurodevelopmentally at corrected ages of 18 to 22 months. Outcomes were defined as Bayley Scales of Infant Development-II Mental Development Index of RESULTS. A total of 1124 infants met entry criteria. There were no statistically significant associations between prenatal dexamethasone exposure and any follow-up outcome, compared with no prenatal steroid exposure. Prenatal betamethasone exposure was associated with reduced risks of hearing impairment and neurodevelopmental impairment and with increased likelihood of unimpaired status, compared with no prenatal steroid exposure. Compared with betamethasone, dexamethasone was associated with a trend for increased risk of Psychomotor Development Index of CONCLUSIONS. Prenatal betamethasone exposure was associated with increased likelihood of unimpaired neurodevelopmental status and reduced risk of hearing impairment at corrected ages of 18 to 22 months among extremely low birth weight infants, compared with prenatal dexamethasone exposure or no prenatal steroid exposure. Pending a randomized, clinical trial, it may be in the best interests of infants to receive betamethasone, rather than dexamethasone, when possible.
Cosmic‐Ray History and Its Implications for Galactic Magnetic Fields

There is evidence that cosmic rays were present in galaxies at moderately high redshift. This suggests that magnetic fields were also present. If cosmic rays and magnetic fields must always be close to equipartition, as they are to an order of magnitude within the local universe, this would provide a powerful constraint on theories of the origin and evolution of magnetic fields in galaxies. We evaluate the role of magnetic field strength in cosmic-ray acceleration and confinement. We find that the properties of small-scale hydromagnetic turbulence are fundamentally changed in the presence of cosmic rays. As a result, magnetic fields several orders of magnitude weaker than present galactic fields can accelerate and retain a population of relativistic cosmic rays, provided that the fields are coherent over length scales greater than a cosmic-ray gyroradius.
Neutron irradiation-induced dimensional changes in MEMS glass substrates

Abstract A study is made of radiation-induced expansion/compaction in Pyrex ® (Corning 7740) and Hoya SD-2 ® glasses, which are used as substrates for MEMS devices. Glass samples were irradiated with a neutron fluence composed primarily of thermal neutrons, and a flotation technique was employed to measure the resulting density changes in the glass. Transport of Ions in Matter (TRIM) calculations were performed to relate fast (∼1 MeV) neutron atomic displacement damage to that of boron thermal neutron capture events, and measured density changes in the glass samples were thus proportionally attributed to thermal and fast neutron fluences. Pyrex was shown to compact at a rate of (in Δ ρ / ρ per n/cm 2 ) 8.14 × 10 −20 (thermal) and 1.79 × 10 −20 (fast). The corresponding results for Hoya SD-2 were 2.21 × 10 −21 and 1.71 × 10 −21 , respectively. On a displacement per atom (dpa) basis, the compaction of the Pyrex was an order of magnitude greater than that of the Hoya SD-2. Our results are the first reported measurement of irridiation-induced densification in Hoya SD-2. The compaction of Pyrex agreed with a previous study. Hoya SD-2 is of considerable importance to MEMS, owing to its close thermal expansivity match to silicon from 25 to 500°C.
Identifying consumer consideration set at the purchase time from aggregate purchase data in online retailing

Online retailers provide a substantial amount of product information to their customers. The information includes not only product features and customer reviews, but also information on alternative products that may better fit a consumer's needs. The systematic provision of information on alternative products could have a significant impact on consumers' purchase decision process at online retailers. In this study, we analyze one aspect of the impact - the degree to which consumers consider multiple products at the purchase time. We leverage a popular feature provided by online retailers - ''What Do Customers Ultimately Buy after Viewing This Item?'' We show that information contained in this feature can be used to identify consumers' product consideration set and choice at the purchase time when combined with product sales data. The identification is exact in analyzing competition between two products. For competition involving three products, the identification is exact under the assumption that consumer choice follows a discrete choice model. For competition involving more than three products, the information provides a lower bound of the percentage of consumers that consider only one product at the purchase time. We apply the model to 38,400 unique products from Amazon's Electronics category. The results show that more than 78% of consumers purchase a product without considering any other products on Amazon at the purchase time.
Network Compression: Memory-assisted universal coding of sources with correlated parameters

The existence of significant amount of correlation in the network traffic has stimulated the development of innetwork traffic reduction techniques since end-to-end universal compression solutions would not perform well over Internet packets due to the finite-length nature of data. Recently, we proposed a memory-assisted universal compression technique that holds a significant promise for reducing the amount of traffic in the networks. The idea is based on the observation that if a finite-length sequence from a server (source) is to be compressed and transmitted over the network, the associated universal code entails a substantial overhead. On the other hand, intermediate nodes can reduce the transmission overhead by memorizing the source statistics when forwarding the sequences from the previous communications with the server. In this paper, we extend this idea to the scenario where multiple servers are present in the network by proposing distributed network compression via memory. We consider two spatially separated sources with correlated unknown source parameters. We wish to study the universal compression of a sequence of length n from one of the sources provided that the decoder has access to (i.e., memorized) a sequence of length m from the other source. In this setup, the correlation does not arise from symbol-by-symbol dependency of two outputs from the two sources (as in Slepian-Wolf setup). Instead, the two sequences are correlated because they are originated from the two sources with unknown correlated parameters. The finite-length nature of the compression problem at hand requires considering a notion of almost lossless source coding, where coding incurs an error probability p e (n) that vanishes as sequence length n grows to infinity. We obtain bounds on the redundancy of almost lossless codes when the decoder has access to a random memory of length m as a function of the sequence length n and the permissible error probability p e (n). Our results demonstrate that distributed network compression via memory has the potential to significantly improve over conventional end-to-end compression when sufficiently large memory from previous communications is available to the decoder.
Quick gossiping without duplicate transmissions

There aren people, each knowing a gossip. They communicate by phone calls, and whenever two persons talk they tell all information they know at that time. Denote byf(n) the minimal number of necessary calls when everybody hears each gossip exactly once. We prove thatf(n) = 2.25n ? 6 ifn = 4k, k ? 2 and 2.25n ? 4.5 ≤f(n) ≤ 2.25n ? 3.5 ifn = 4k + 2,k ? 5. (Ifn is odd, orn = 4k + 2, 0 <k < 5 then there are no appropriate sequences of calls at all.)
QUARKS AND MAGNETIC POLES.

A theory is developed which accounts for the free nonrelativistic motion of fractionally charged quarks within hadrons, and at the same time does not permit quarks to appear as individuals. This is accomplished by modifying Dirac's idea that the quantization of electric charge derives from the existence of a point magnetic pole, to include the situation in which the pole is extended in space and of hadronic size. The needed formalism makes use of Mandelstam's gauge-independent, path-dependent quantum electrodynamics, as extended by Cabibbo and Ferrari to include the existence of point magnetic poles. It is shown that the further extension to a pole of finite size and the use of parallel straight paths are the only new features that are required. In particular, no assumptions need be made with regard to the masses of quarks, the interactions between them, or the existence of a constraining potential.
The perturbation spectrum of black holes in N = 8 supergravity

Abstract The near horizon geometry of four-dimensional black holes in the dilute gas regime is AdS 3 × S 2 , and the global symmetry group is SU (2) × USp (6). This is exploited to calculate their perturbation spectrum using group theoretical methods. The result is interpreted in terms of three extreme M5-branes, orthogonally intersecting over a common string. We also consider N = 8 black holes in five dimensions, and compute the spectrum by explicit decoupling of the equations of motion, extending recent work on N = 4 black holes. This result is interpreted in terms of D1- and D5-branes that are wrapped on a small four-torus. The spectra are compared with string theory.
DIFFERENCE AND DIFFERENTIAL EQUATIONS FOR THE COLORED JONES FUNCTION

The colored Jones function of a knot is a sequence of Laurent polynomials. It was shown by Le and the author that such sequences are q-holonomic, that is, they satisfy linear q-difference equations with coefficients Laurent polynomials in q and qn. We show from first principles that q-holonomic sequences give rise to modules over a q-Weyl ring. Frohman–Gelca–LoFaro have identified the latter ring with the ring of even functions of the quantum torus, and with the Kauffman bracket skein module of the torus. Via this identification, we study relations among the orthogonal, peripheral and recursion ideal of the colored Jones function, introduced by the above mentioned authors. In the second part of the paper, we convert the linear q-difference equations of the colored Jones function in terms of a hierarchy of linear ordinary differential equations for its loop expansion. This conversion is a version of the WKB method, and may shed some information on the problem of asymptotics of the colored Jones function of a knot.
Colonization of maternal and fetal tissues by Porphyromonas gingivalis is strain-dependent in a rodent animal model.

Objective The objective of this study was to develop a rodent model of Porphyromonas gingivalis infection during pregnancy. Study Design Sprague Dawley rats were infected intravenously with 10 5 , 10 7 , or 10 9 CFU per dam of P gingivalis strain W83, ATCC 33277, or A7436 at gestational day 14 and necropsied at gestational day 18. Maternal organs were cultured to assess the spread of the infection. Six fetal units (placenta, amniotic fluid, membranes, and fetus) per dam were cultured; additional fetal units were examined by histopathology. Polymerase chain reaction was performed on placentas. Results Colonization rates were dependent on the strain of P gingivalis used and the infection dose. At an infection dose of 10 9 CFU/dam, P gingivalis W83, ATCC 33277, or A7436 was detected in 33%, 83%, or 100% of placentas, respectively. Epithelial hyperplasia, cellular necrosis, and inflammatory infiltrate were observed in infected placental tissues. Conclusion This study demonstrated that P gingivalis can invade both maternal and fetal tissues, resulting in chorioamnionitis and placentitis.
Pulsed Neutron Measurement of Single and Two-Phase Liquid Flow

Use of radioactive tracers for flow velocity measurements is well developed and documented. Measurement techniques involving pulsed sources of fast (14 MeV) neutrons for in-situ production of tracers can be considered as extensions of the old methods. Improvements offered by these Pulsed Neutron Activation (PNA) techniques over conventional radioisotope techniques are (1) non-intrusion into the system, (2) easier introduction and better mixing of the tracer, and (3) no requirement to handle large amounts of relatively long lived radioactive materials. Just as in conventional tracer techniques, flow velocity measurements by PNA methods can be based on the transit-time or the total-count method. A very significant difference of the PNA technique from conventional methods is that the induced activity is proportional to the density of the fluid, and that PNA techniques can be used for density measurements (of two-phase flows) in addition to flow velocity measurement. Original equations were derived that relate experimental data to the mass flow velocity and the average density. The accuracy of these equations is not effected by the flow regime. Experimental results are presented for tests performed on liquid sodium loops, on air-water loops, on the EBR-II reactor and on the LOFT reactor. Current instrumentation development programs (detectors, pulsed neutron sources) are discussed.
Understanding Multidecadal Variability in ENSO Amplitude

AbstractSea surface temperatures (SSTs) in the tropical Pacific vary as a result of the coupling between ocean and atmosphere driven largely by El Nino–Southern Oscillation (ENSO). ENSO amplitude is known to vary on long time scales, which makes it difficult to quantify its response to climate change and constrain the physical processes that drive it. To characterize the long-period variability in ocean–atmosphere coupling strengths, a linear regression of local SST changes is applied to the 4000-yr GFDL Climate Model, version 2.1 (CM2.1) and the 500-yr GFDL CM2 with Modular Ocean Model version 4p1 (MOM4p1) at coarse resolution (CM2Mc) preindustrial control runs, while also comparing to the observationally constrained Ensemble Coupled Data Assimilation (ECDA) dataset. The models produce regression coefficients that vary widely on multidecadal time scales. These variations are strongly reflected in the long-period modulation of ocean stratification and surface precipitation. During high variance periods, w...
A Maximum Entropy Approach to Identifying Sentence Boundaries

We present a trainable model for identifying sentence boundaries in raw text. Given a corpus annotated with sentence boundaries, our model learns to classify each occurrence of., ?, and ! as either a valid or invalid sentence boundary. The training procedure requires no hand-crafted rules, lexica, part-of-speech tags, or domain-specific information. The model can therefore be trained easily on any genre of English, and should be trainable on any other Romanalphabet language. Performance is comparable to or better than the performance of similar systems, but we emphasize the simplicity of retraining for new domains.
Porcine Liver Esterase Catalyzed Kinetic Resolution of Baylis-Hillman (B-H) Adducts

Abstract Esterase from porcine liver smoothly resolves varieties of racemic 2-methylene-3-substituted-3-hydroxypropanoates (B-H adducts) to obtain the corresponding unreacted esters in very good to excellent ee (94 to >99%, seven examples) and hydrolyzed acids in good ee (58–75%). Substitution in B-H adducts, chosen for resolution, are funtionalized phenyl, thiophen-3-yl, cinnamyl, and alkyl groups. †DRL Pub. No. 232. Dedicated to Dr. A. Venkateswarlu on the occasion of his 63rd birth anniversary
Decision theory with resource-bounded agents.

There have been two major lines of research aimed at capturing resource-bounded players in game theory. The first, initiated by Rubinstein (1986), charges an agent for doing costly computation; the second, initiated by Neyman (1985), does not charge for computation, but limits the computation that agents can do, typically by modeling agents as finite automata. We review recent work on applying both approaches in the context of decision theory. For the first approach, we take the objects of choice in a decision problem to be Turing machines, and charge players for the “complexity” of the Turing machine chosen (e.g., its running time). This approach can be used to explain well-known phenomena like first-impression-matters biases (i.e., people tend to put more weight on evidence they hear early on) and belief polarization (two people with different prior beliefs, hearing the same evidence, can end up with diametrically opposed conclusions) as the outcomes of quite rational decisions. For the second approach, we model people as finite automata, and provide a simple algorithm that, on a problem that captures a number of settings of interest, provably performs optimally as the number of states in the automaton increases.
Further intramolecular Diels-Alder reactions of 1,2,4-triazines: synthesis of dihydropyrrolo[2,3-b]pyridines

Abstract 3-(3-Butynylamino)-1,2,4-triazines undergo intramolecular Diels-Alder reactions to yield 2,3-dihydropyrrolo[2,3- b ]pyridines.
Network Reliability under Random Circular Cuts

Optical fiber networks consist of fibers that are laid out along physical terrestrial paths. As such, they are vulnerable to geographical physical failures, such as earthquakes and Electromagnetic Pulse (EMP) attacks. Moreover, such disasters can lead to multiple, geographically correlated, failures on the fiber network. Thus, the geographical layout of the fiber infrastructure has a critical impact on the robustness of the network in the face of such geographical physical failures. In this paper, we develop tools to analyze network connectivity after a `random' geographic disaster. The random location of the disaster allows us to model situations where the physical failures are not targeted attacks. In particular, we consider disasters that take the form of a `randomly' located disk in a plane. Using results from geometric probability, we are able to approximate some network performance metrics to such a disaster in polynomial time. We present some numerical results that make clear geographically correlated failures are fundamentally different from independent failures and then discuss network design in the context of random disk-cuts.
Operational semantics for multi-language programs

Interoperability is big business, a fact to which .NET, the JVM, and COM can attest. Language designers are well aware of this, and they are designing programming languages that reflect it—for instance, SML.NET, Fn, Mondrian, and Scala all treat interoperability as a central design feature. Still, current multi-language research tends not to focus on the semantics of these features, but only on how to implement them efficiently. In this article, we attempt to rectify that by giving a technique for specifying the operational semantics of a multi-language system as a composition of the models of its constituent languages. Our technique abstracts away the low-level details of interoperability like garbage collection and representation coherence, and lets us focus on semantic properties like type-safety, equivalence, and termination behavior. In doing so it allows us to adapt standard theoretical techniques such as subject-reduction, logical relations, and operational equivalence for use on multi-language systems. Generally speaking, our proofs of properties in a multi-language context are mutually referential versions of their single language counterparts.We demonstrate our technique with a series of strategies for embedding a Scheme-like language into an ML-like language. We start by connecting very simple languages with a very simple strategy, and work our way up to languages that interact in sophisticated ways and have sophisticated features such as polymorphism and effects. Along the way, we prove relevant results such as type-soundness and termination for each system we present using adaptations of standard techniques.Beyond giving simple expressive models, our studies have uncovered several interesting facts about interoperability. For example, higher-order function contracts naturally emerge as the glue to ensure that interoperating languages respect each other's type systems. Our models also predict that the embedding strategy where foreign values are opaque is as expressive as the embedding strategy where foreign values are translated to corresponding values in the other language, and we were able to experimentally verify this behavior using PLT Scheme's foreign function interface.
Generalized halo independent comparison of direct dark matter detection data

We extend the halo-independent method to compare direct dark matter detection data, so far used only for spin-independent WIMP-nucleon interactions, to any type of interaction. As an example we apply the method to magnetic moment interactions.
Audit Committee Quality and Internal Control: An Empirical Analysis

I examine the association between audit committee quality and the quality of corporate internal control. While information on the quality of internal control is not generally available, companies changing auditors are required to disclose any internal control problems that were pointed out by their predecessor auditors. The empirical results are based on a comparison of companies disclosing such internal control problems with a control sample of companies changing auditors but not disclosing internal control problems. Audit committee quality is measured in three dimensions: its size, its independence, and its expertise. The internal control problems are observed at two levels of increasing seriousness: reportable conditions and material weaknesses. The sample time period precedes the effective dates of recent policy changes regarding audit committees. The results indicate that independent audit committees and audit committees with financial expertise are significantly less likely to be associated with the...
Threshold voltage instability at low temperatures in partially depleted thin-film SOI MOSFETs

A threshold voltage instability phenomenon at low temperatures in partially depleted thin-film silicon-on-insulator (SOI) SIMOX (separation by implantation of oxygen) MOSFETs is reported. This phenomenon was investigated under normal MOSFET operating conditions for temperatures ranging from 300 K down to 10 K, with both the magnitude and duration of the instability observed to be strongly dependent on temperature. Threshold voltage shifts as small as 0 V at room temperature and as large as 0.29 V at 10 K are reported. The duration of the instability ranged in the tens of minutes and was observed to increase as the temperature was decreased. >
Deflation of Eigenvalues for GMRES in Lattice QCD

Abstract Versions of GMRES with deflation of eigenvalues are applied to lattice QCD problems. Approximate eigenvectors corresponding to the smallest eigenvalues are generated at the same time that linear equations are solved. The eigenvectors improve convergence for the linear equations, and they help solve other right-hand sides.
Imaging With A Multiplane Multiwire Proportional Chamber Using Heavy Ion Beams

A 16-plane multiwire proportional chamber has been developed to accurately map intensity pro files of heavy ion beams at the Bevalac. The imaging capability of the system has been tested for reconstruction of 3-dimensional representation of a canine thorax region using heavy ion beams.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
(BiSe)1.23CrSe2 and (BiSe)1.22(Cr1.2Se2)2: magnetic anisotropy in the first structurally characterized Bi-Se-Cr ternary compounds

Compounds containing both heavy main group elements and paramagnetic transition metals form a fertile area for the study of magnetic anisotropy. We pursued the synthesis, characterization, and magnetic measurements of Bi-Se-Cr compounds: a ternary system with no structurally characterized materials. Those efforts led to the isolation of two novel misfit layer compounds, namely, (BiSe)1.23CrSe2 (1) and (BiSe)1.22(Cr1.2Se2)2 (2). The crystal structure of 1 consists of alternating BiSe and CrSe2 layers along the c-axis, and 2 is composed of alternating BiSe and (Cr1.2Se2)2 layers along the c-axis. Lattice mismatch occurs in both compounds along the b-axis and leads to positional modulation of the atoms. Field- and temperature-dependent measurements were performed to assess the degree of magnetic anisotropy. Temperature-dependent susceptibility measurements on aligned crystals of 1 display increased bifurcation of zero-field cooled and field cooled data when crystals are oriented with H perpendicular to c than when the crystals are oriented with H parallel to c. Magnetic anisotropy is less pronounced in 2 where both crystallographic orientations exhibit bifurcation at 26 K. The complexity of the magnetic behavior in both compounds likely signifies a competition between CrSe2 intralayer ferromagnetic coupling and interlayer antiferromagnetic coupling. These results highlight the exciting magnetic properties that can arise from the exploration of new ternary phases.
Evidence for thin-target X-ray emission in a small solar flare on 26 February 1972

We compare solar X-ray observations from the UCSD experiment aboard OSO-7 with high resolution energetic electron observations from the UCAL experiment on IMP-6 for a small solar flare on 26 February 1972. A proportional counter and NaI scintillator covered the X-ray energy range 5–300 keV, while a semiconductor detector telescope covered electrons from 18 to ∼ 400 keV. A series of four non-thermal X-ray spikes were observed from 1805 to 1814 UT with average spectrum dJ/d (hv) ∼ (hv)−4.0 over the 14–64 keV range. The energetic electrons were observed at 1 AU beginning 1840 UT with a spectrum dJ/dE ∼ E−3.1. If the electrons which produce the X-ray emission and those observed at 1 AU are assumed to originate in a common source, then these observations are consistent with thin target X-ray production at the Sun and inconsistent with thick target production. Under a model consistent with the observed soft X-ray emission, we obtain quantitative estimates of the total energy, total number, escape efficiency, and energy lost in collisions for the energetic electrons.
The Fatou set for critically finite maps

It is a classical result in complex dynamics of one variable that the Fatou set for a critically finite map on P 1 consists of only basins of attraction for superattracting periodic points. In this paper, we deal with critically finite maps on P k . We show that the Fatou set for a critically finite map on P 2 consists of only basins of attraction for superattracting periodic points. We also show that the Fatou set for a k-critically finite map on P k is empty.
Experimental Study of the Effect of Span Loading on Aircraft Wakes

Measurements were made in the NASA-Ames 40- by 80-Foot Wind Tunnel of the rolling moment induced on a following model in the wake 13.6 spans behind a subsonic transport model for a variety of trailing edge flap settings of the generator. It was found that the rolling moment on the following model was reduced substantially, compared to the conventional landing configuration, by reshaping the span loading on the generating model to approximate a span loading, found in earlier studies, which resulted in reduced wake velocities. This was accomplished by retracting the outboard trailing edge flaps. It was concluded, based on flow visualization conducted in the wind tunnel as well as in a water tow facility, that this flap arrangement redistributes the vorticity shed by the wing along the span to form three vortex pairs that interact to disperse the wake.
Time-Series Ensemble Photometry and the Search for Variable Stars in the Open Cluster M11

This work presents the first large-scale photometric variability survey of the intermediate-age (~200 Myr) open cluster M11. Thirteen nights of data over two observing seasons were analyzed (using crowded field and ensemble photometry techniques) to obtain high relative precision photometry. In this study we focus on the detection of candidate member variable stars for follow-up studies. A total of 39 variable stars were detected and can be categorized as follows: one irregular (probably pulsating) variable, six δ Scuti variables, 14 detached eclipsing binary systems, 17 W UMa variables, and one unidentified/candidate variable. While previous proper-motion studies allow for cluster membership determination for the brightest stars, we find that membership determination is significantly hampered below V = 15, R = 15.5 by the large population of field stars overlapping the cluster main sequence. Of the brightest detected variables that have a high likelihood of cluster membership, we find five systems in which further work could help constrain theoretical stellar models, including one potential W UMa member of this young cluster.
Symmetry: the search for order in Nature

After an historical introduction of the concept of symmetry, the many ways in which symmetry is used today in physics are briefly reviewed. A new concept, super-symmetry, introduced in the 1970's is also briefly reviewed, and the only experimental example of supersymmetry in physics presented. The future of symmetry in physics is briefly discussed.
ROTATING NEUTRON STARS, PULSARS, AND COSMIC X-RAY SOURCES.

The purpose of this paper is to discuss the relationship between rotating neutron stars, pulsars, and cosmic X-ray sources. The latter may be divided into at least two classes: the sources with large angular diameters, such as the Crab Nebula, and those with small angular diameter, such as Sco X-1. I submit that a basic model, consisting of a rotating neutron star losing mass in the presence of a large magnetic field, can account for both types of X-ray source. The extended sources represent the case where the energy in the ‘neutron-star wind’ is greater than the magnetic energy. The streaming protons and electrons deposit their energy far out into the nebula in a shock transition region. The relativistic electrons responsible for the extended sources of radio, optical and X-ray emission are produced in the transfer of energy between the protons and electrons in the shock wave, and by magnetic pumping in hydromagnetic waves which are generated by fluctuations in the mass loss rate. The compact sources, such as Sco X-1, represent the other extreme where the magnetic energy dominates, so that no mass loss occurs. The particles are then accelerated and radiate in radiation belts around the neutron star, resulting in a source with a small angular diameter.
Glycosyl thioimidates in a highly convergent one-pot strategy for oligosaccharide synthesis

Application of two classes of thioimidoyl derivatives, S-benzoxazolyl (SBox) and S-thiazolyl (STaz) glycosides to selective activation over thioglycosides is described. These results allowed us to synthesize a tetrasaccharide derivative using a leaving group differentiated one-pot strategy in 73% yield over three sequential glycosylation steps.
How universal is the fractional-quantum-Hall edge Luttinger liquid?

Abstract This article reports on our microscopic investigations of the edge of the fractional quantum Hall state at filling factor ν=1/3. We show that the interaction dependence of the wave function is well described in an approximation that includes mixing with higher composite-fermion Landau levels in the lowest order. We then proceed to calculate the equal time edge Green function, which provides evidence that the Luttinger exponent characterizing the decay of the Green function at long distances is interaction dependent. The relevance of this result to tunneling experiments is discussed.
Prospect Theory and the Framing of the Good Friday Agreement

We examine how supporters of the 1998 Good Friday Agreement tried to persuade their constituents to vote for ratifying the agreement. We argue that a “sales” message based on tenets of prospect theory—framing the preferred choice as less risky than the alternative—garnered more support for the initial vote and, more important, insulated the process to some extent from failures in implementation. For this article, we determine how political leaders supporting the agreement framed it, finding that they attempted to do so both positively toward a better future and as a better alternative to continued or renewed conflict.