cssi/SciSciGPT-SciSciNet huggingface dataset:
Using fractal dimensionality in the search for source models of ultra-high energy cosmic rays

Abstract Although the existence of cosmic rays with energies extending well above 10 19 eV has been confirmed, their origin remains one of the most important questions in astro-particle physics today. Several source models have been proposed for the observed set of ultra high energy cosmic rays (UHECRs). Yet none of these models have been conclusively identified as corresponding with all of the available data. One possible way of achieving a global test of anisotropy is through the measurement of the information dimension, D I , of the arrival directions of a sample of events. D I is a measure of the intrinsic heterogeneity of a data sample. We will show how this method can be used to take into account the extreme asymmetric angular resolution and the highly irregular aperture of a monocular air-fluorescence detector. We will then use a simulated, isotropic event sample to show how this method can be used to place upper limits on any number of source models with no statistical penalty.
Phosphine-Catalyzed Reductions of Alkyl Silyl Peroxides by Titanium Hydride Reducing Agents: Development of the Method and Mechanistic Investigations

A method that allows for the reduction of protected hydroperoxides by employing catalytic amounts of phosphine is presented. The combination of a titanium(IV) alkoxide and a siloxane allowed for the chemoselective reduction of phosphine oxides in the presence of alkyl silyl peroxides. Subsequent reduction of the peroxide moiety by phosphine provided the corresponding silylated alcohols in useful yields. Mechanistic experiments, including crossover experiments, support a mechanism in which the peroxide group was reduced and the silyl group was transferred in a concerted step. Labeling studies with 17O-labeled peroxides demonstrate that the oxygen atom adjacent to the silicon atom is removed from the silyl peroxide.
The impact of an online learning community project on university Chinese as a foreign language students' motivation

This study investigated the impact of an online learning community project on university students’ motivation in learning Chinese as a foreign language. A newly proposed second language (L2) motivation theory—the L2 motivational self system (Dornyei, 2005, 2009)—guided this study. A concurrent transformative mixed-methods design was employed to collect both quantitative and qualitative data through the pre- and posttest of a questionnaire. Results from paired t tests indicated a significant difference in the L2 learning experience aspect of motivation before and after the online project, while there was no significant difference in the other two aspects of motivation (i.e., the ideal L2 self and the ought-to L2 self). Specific motivating and demotivating features of the online project were identified from participants’ responses to an open-ended question.
Dirac cohomology for graded affine Hecke algebras

We define an analogue of the Casimir element for a graded affine Hecke algebra \( \mathbb{H} \), and then introduce an approximate square-root called the Dirac element. Using it, we define the Dirac cohomology HD (X) of an \( \mathbb{H} \)-module X, and show that HD (X) carries a representation of a canonical double cover of the Weyl group \( \widetilde{W} \). Our main result shows that the \( \widetilde{W} \)-structure on the Dirac cohomology of an irreducible \( \mathbb{H} \)-module X determines the central character of X in a precise way. This can be interpreted as p-adic analogue of a conjecture of Vogan for Harish-Chandra modules. We also apply our results to the study of unitary representations of \( \mathbb{H} \).
Selective sinoatrial node optical mapping and the mechanism of sinus rate acceleration.

Background: Studies using isolated sinoatrial node (SAN) cells indicate that rhythmic spontaneous sarcoplasmic reticulum calcium release (Ca clock) plays an important role in SAN automaticity. In the intact SAN, cross-contamination of optical signals from the SAN and the right atrium (RA) prevent the definitive testing of Ca clock hypothesis. The aim of this study was to use a novel approach to selectively mapping the intact SAN to examine the Ca clock mechanism. Methods and Results: We simultaneously mapped intracellular Ca (Cai) and membrane potential (Vm) in 10 isolated, Langendorff-perfused normal canine RAs. The excitability of the RA was suppressed with high-potassium Tyrode's solution, allowing selective optical mapping of Vm and Cai of the SAN. Isoproterenol (ISO, 0.03μmol/L) decreased the cycle length of the sinus beats, and shifted the leading pacemaker site from the middle or inferior SAN to the superior SAN in all RAs. The Cai upstroke preceded the Vm in the leading pacemaker site by up to 18±2ms. ISO-induced changes to SAN were inhibited by ryanodine (3μmol/L), but not ZD7288 (3μmol/L), a selective If blocker. Conclusions: We conclude that, in the isolated canine RA, a high extracellular potassium concentration can suppress atrial excitability thus leading to SAN-RA conduction block, allowing selective optical mapping of the intact SAN. Acceleration of Ca cycling in the superior SAN underlies the mechanism of sinus tachycardia during sympathetic stimulation. (Circ J 2012; 76: 309-316)
Analyzing Industrial Furnace Efficiency Using Comparative Visualization in a Virtual Reality Environment

We describe an interactive toolkit used to perform comparative analysis of two or more data sets arising from numerical simulations. Several techniques have been incorporated into this toolkit, including (I) successive visualization of individual data sets, (2) data comparison techniques such as computation and visualization of the differences between data sets, and (3) image comparison methods such as scalar field height profiles plotted in a common coordinate system. We describe each technique in detail and show example usage in an industrial application aimed at designing an efficient, low-NO x burner for industrial furnaces. Critical insights are obtained by interactively adjusted color maps, data culling, and data manipulation. New paradigms for scaling small values in the data comparison technique are described. The display device used for this application is the CAVE virtual reality theater, and we describe the user interface to the visualization toolkit and the benefits of immersive 3D visualization for comparative analysis.
NEARBY GALAXIES IN MORE DISTANT CONTEXTS

We use published reconstructions of the star formation history (SFH) of the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and NGC 300 from the analysis of resolved stellar populations to investigate where such galaxies might land on well-known extragalactic diagnostic plots over the galaxies' lifetime (assuming that nothing other than their stellar populations change). For example, we find that the evolution of these galaxies implies a complex evolution in the Tully-Fisher relation with look-back time and that the observed scatter is consistent with excursions these galaxies take as their stellar populations evolve. We find that the growth of stellar mass is weighted to early times, despite the strongly star-forming current nature of the three systems. Lastly, we find that these galaxies can take circuitous paths across the color-magnitude diagram. For example, it is possible, within the constraints provided by the current determination of its SFH, that the LMC reached the red sequence at intermediate age prior to ending back up on the blue cloud at the current time. Unfortunately, this behavior happens at sufficiently early times that our resolved SFH is crude and insufficiently constraining to convincingly demonstrate that this was the actual evolutionary path. The limited sample size precludesmore » any general conclusions, but we present these as examples how we can bridge the study of resolved populations and the more distant universe.« less
Characteristic functions and joint invariant subspaces

Let T:=[T1,…,Tn] be an n-tuple of operators on a Hilbert space such that T is a completely non-coisometric row contraction. We establish the existence of a “one-to-one” correspondence between the joint invariant subspaces under T1,…,Tn, and the regular factorizations of the characteristic function ΘT associated with T. In particular, we prove that there is a non-trivial joint invariant subspace under the operators T1,…,Tn, if and only if there is a non-trivial regular factorization of ΘT. We also provide a functional model for the joint invariant subspaces in terms of the regular factorizations of the characteristic function, and prove the existence of joint invariant subspaces for certain classes of n-tuples of operators. We obtain criteria for joint similarity of n-tuples of operators to Cuntz row isometries. In particular, we prove that a completely non-coisometric row contraction T is jointly similar to a Cuntz row isometry if and only if the characteristic function of T is an invertible multi-analytic operator.
NEUTRON SCATTERING AND POLARIZATION BY FERROMAGNETIC MATERIALS

Neutron diffraction studies are reported on a series of magnetized and unmagnetized ferromagnetic materials. The diffraction patterns for unmagnetized, polycrystalline samples of Fe and Co are found to possess both nuclear and magnetic components with the latter in agreement with the magnetic scattering theory with respect both to intensity of scattering and form factor angular variation. Studies on the magnetic structure of ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$ are shown to strongly support N\'eel's proposed ferrimagnetic structure. Predictions of the theory regarding intensity effects upon sample magnetization are fully confirmed and the Schwinger-Halpern-Johnson formulation of the interaction function between the neutron's magnetic moment and the internal fields in a ferromagnet is substantiated. A pronounced variation of intensity around the Debye ring in the diffraction pattern for a magnetized sample is found. Neutron polarization effects in the Bragg scattered beams from magnetized crystals of Fe and ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$ have been studied and it is shown that very highly polarized beams are obtained for certain reflections. This method of monochromatic beam polarization is found to compare very favorably with other methods with respect to polarization value, beam intensity, and ease of obtainment.
Air-sea gas transfer in the Southern Ocean

[1] Gas transfer velocities were determined in the Southern Ocean during the Southern Ocean Iron Fertilization experiment (SOFex) using the dual deliberate tracer technique. The decrease of the purposefully injected tracers, sulfur hexafluoride and helium-3, could be well described by gas exchange parameterizations with wind speed that satisfy global constraints based on bomb-14C uptake. The concentration decrease of tracers could be predicted slightly better with established relationships if gas transfer was modeled as a function of the cube rather than the square of the wind speed, particularly over a time interval with high and variable winds. However, both fits can model the concentration decrease within the uncertainty of the observations. This suggests that it will be singularly difficult to definitively determine if a quadratic or cubic dependence of gas exchange with wind is more appropriate based on deliberate tracer measurements. However, these results show that gas exchange rates in the Southern Ocean are not anomalous when compared with the rest of the ocean. Thus this cannot account for discrepancy between observational and model-based estimates of uptake of CO2 in the Southern Ocean. Using a high-quality wind speed field obtained from the QuikSCAT satellite Seawinds scatterometer and an established surface water pCO2 climatology, the CO2 uptake in the Southern Ocean (>34°S) is reassessed. The total uptake rates are similar to previous observation-based estimates, but the analysis shows that the uptake rate is sensitive to wind speed product used and the wind speed distribution.
Synthesis of Octahydro 1H-Pyrrolo[1,2-a]indol-3-ones Via Intramolecular Diels-Alder Reaction of 5-Substituted N-Dienyl Lactams

Abstract N-dienyl-5-alkenyl-lactams can be prepared from succinimide. Heating leads to an intramolecular Diels-Alder cyclization that produces tricyclic products useful for the preparation of related alkaloids.
Manipulation and Equity-Based Compensation

Economists have long argued that a strong linkage between compensation and performance is essential for resolving the agency problem created by the separation of ownership and control. In particular Michael C. Jensen and Kevin J. Murphy (1990) were very influential in giving impetus to the view that such incentives were in need of strengthening. Compared to accounting benchmarks, the stock price is more forward looking, and it is responsive to all value-relevant information, including informal and unverifiable items of news. This makes stock and/or option awards an important part of optimal incentives, and constitutes a primary reason for seeking a public listing, as argued by Bengt Holmstrom and Jean Tirole (1993). Until recently, however, theories of optimal executive compensation have generally ignored the possibility that the stock price can be manipulated or falsified. It is becoming increasingly clear that this is an important issue. In a spate of recent scandals, companies have misled the investing public by vastly overstating their profitability and prospects, and substantive restatements of company accounts have become increasingly commonplace. A growing body of empirical evidence suggests that executive pay in its current form may be at least in part responsible. Recent studies finding a link between unusual movements in performance measures (such as accounting yardsticks and publicly disclosed price-sensitive information) and compensation include Daniel Bergstresser and Thomas Philippon (2006), Natasha Burns and Simi Kedia (2006), and Peng and Roell (forthcoming). Thus, the benefits of stock-based incentives should be weighed against their side effects. This paper models optimal executive compensation in a setting where managers are in a position to influence the public perception of Manipulation and Equity-Based Compensation
Client requirements for real-time communication services

A set of performance specifications that seem appropriate for real-time computer communication services is proposed. They include various types of delay bounds, throughput bounds, and reliability bounds. Other requirements and desirable properties are described from a client's viewpoint, and the ways in which each requirement is to be translated to make it suitable for lower levels in the protocol hierarchy are examined. Some examples of requirements specification are presented, and possible objections to the approach are discussed. >
The role of location in evaluating racial wage disparity

A standard object of empirical analysis in labor economics is a modified Mincer wage function in which an individual's log wage is specified to be a function of education, experience, and an indicator variable identifying race. We analyze this approach in a context in which individuals live and work in different locations (and thus face different housing prices and wages). Our model provides a justification for the traditional approach, but with the important caveat that the regression should include location-specific fixed effects. Empirical analyses of men in U.S. labor markets demonstrate that failure to condition on location causes us to (i) overstate the decline in black-white wage disparity over the past 60 years, and (ii) understate racial and ethnic wage gaps that remain after taking into account measured cognitive skill differences that emerge when workers are young.
ASIC for High Rate 3D Position Sensitive Detectors

We report on the development of an application specific integrated circuit (ASIC) for 3D position sensitive detectors (3D PSD). The ASIC is designed to operate with pixelated wide bandgap sensors like Cadmium-Zinc-Telluride (CZT), Mercuric Iodide (Hgl2) and Thallium Bromide (TIBr). It measures the amplitudes and timings associated with an ionizing event on 128 anodes, the anode grid, and the cathode. Each channel provides low-noise charge amplification, high-order shaping with peaking time adjustable from 250 ns to 12 μs, gain adjustable to 20 mV/fC or 120 mV/fC (for a dynamic range of 3.2 MeV and 530 keV in CZT), amplitude discrimination with 5-bit trimming, and positive and negative peak and timing detections. The readout can be full or sparse, based on a flag and single- or multi-cycle token passing. All channels, triggered channels only, or triggered with neighbors can be read out thus increasing the rate capability of the system to more than 10 kcps. The ASIC dissipates 330 mW which corresponds to about 2.5 mW per channel.
Citizen Control: Race at the Welfare Office

Objectives Individual relationships to the state are shaped through encounters with a variety of institutions. Little scholarly attention has been devoted to how citizenship is shaped through everyday interactions with the social service arm of the state through local “welfare” offices. In Washington State, one-third of all residents are served by the state's primary social service agency. Does this state agency send different messages about citizenship to individuals according to race? We examine this question through encounters of individuals with front-line welfare office staff. Methods Using a systematic audit method, we collected data from 54 Community Service Offices in Washington State to explore messages sent to individuals. Results We find consistent relationships between race and the quantity of information received and the quality of the interaction with the representatives of the state. Conclusions Our findings provide evidence that the state reinforces notions of both belonging and marginalization through patterns of racialized encounters with the state.
Polygon containment and translational min-Hausdorff-distance between segment sets are 3sum-hard

The 3SUM problem represents a class of problems conjectured to require Ω(n2) time to solve, where n is the size of the input. Given two polygons P and Q in the plane, we show that some variants of the decision problem, whether there exists a transformation of P that makes it contained in Q, are 3SUM-hard. In the first variant P and Q are any simple polygons and the allowed transformations are translations only; in the second and third variants both polygons are convex and we allow either rotations only or any rigid motion. We also show that finding the translation in the plane that minimizes the Hausdorff distance between two segment sets is 3SUM-hard.
A Dynamic Representation Model for Service Systems

Current work on service systems is flourishing. Both researchers and practitioners seek to build service systems to create innovative services and increase productivity in the service sector. Unfortunately, most of the existing work focuses on information systems and their lack of models that not only represent entities in service systems with formal methods, but also illustrate a mechanism to achieve innovative services. In this paper, we firstly propose a general service system framework listing static components used in service production and discussing relationships between them. We then introduce a service model to represent pivotal components in service systems and also discuss how to innovate. Since competencies are important components in service systems, we define an ontological description of required competencies to carry out innovative services. We finally present a simple case study to further explain our formal model.
Capital Taxation ∗ Quantitative Explorations of the Inverse Euler Equation

Economies with private information provide a rationale for capital taxation. In this paper we ask what the welfare gains from following this prescription are. We develop a method to answer this question in standard general equilibrium models with idiosyncratic uncertainty and incomplete markets. We find that general equilibrium forces are important and greatly reduce the welfare gains. Once these effects are taken into account, the gains are relatively small in our benchmark calibration. These results do not imply that dynamic aspects of social insurance design are unimportant, but they do suggest that capital taxation may play a modest role.
On bias plus variance

This article presents several additive corrections to the conventional quadratic loss bias-plus-variance formula. One of these corrections is appropriate when both the target is not fixed (as in Bayesian analysis) and training sets are averaged over (as in the conventional bias plus variance formula). Another additive correction casts conventional fixed-trainingset Bayesian analysis directly in terms of bias plus variance. Another correction is appropriate for measuring full generalization error over a test set rather than (as with conventional bias plus variance) error at a single point. Yet another correction can help explain the recent counterintuitive bias-variance decomposition of Friedman for zero-one loss. After presenting these corrections, this article discusses some other loss function-specific aspects of supervised learning. In particular, there is a discussion of the fact that if the loss function is a metric (e.g., zero-one loss), then there is bound on the change in generalization error acco...
Labor market adjustment in transition economies with on-the-job search

This paper examines the impact of on-the-job search by workers in the state sector on the level and duration of unemployment in transition economies. We derive the optimal speed of state sector closure when workers engage in on-the-job search. © 2000 Elsevier Science S.A. All rights reserved.
The perception of Web 2.0 technologies on teaching and learning in higher education: A case study

The purpose of this study was to examine faculty members'perception of Web 2.0 technologies on teaching and learning in higher education compared to traditional classroom teaching methods in programs at a higher education institutions to establish if relationships prevailed in their delivery of courses through the use of Web 2.0 technologies compared with traditional classroom delivery of courses; their overall satisfaction; the level of faculty development programs available; and their perceived effectiveness and impact of faculty development and issues and barriers affecting technology integration. This study also examined the influence of gender, age, and employment status on faculty members’ perceptions of Web 2.0 technologies on teaching and learning in higher education compared to traditional classroom teaching methods. This study used a nonexperimental, quantitative descriptive research design to investigate faculty members’ perception of Web 2.0 technologies on teaching and learning in higher education compared to traditional classroom teaching methods. Participants for this study included full-time and part-time faculty members teaching at a public university in the United States. The results indicated that there is a relationship between faculty members’ perception of teaching college courses utilizing Web 2.0 technologies versus traditional classroom method; there is a relationship between faculty members’ gender and perception regarding their use of Web 2.0 technologies in their courses; and there was a relationship between faculty members'age and perception regarding their use of Web 2.0 technologies in their courses.
Cosmic Gamma-Ray Bursts

The experimental aspects of gamma-ray bursts are reviewed, including their time histories, energy spectra, spatial distribution, recurrence rate, and number-intensity relation. Although the experimental evidence points towards a galactic neutron star origin, it is not universally agreed that all bursts are related to neutron stars. Counterpart searches have failed to identify any quiescent source related to bursters. A related phenomenon, soft gamma repeaters, is presented. Three such sources have been found to date. A brief overview of present and planned experiments and missions is given. Some current theories of gamma-ray bursters are explained, as well as some evolutionary scenarios which might lead to the formation of gamma burst systems.
Nonconvulsive Status Epilepticus

Nonconvulsive status epilepticus (NCSE) is protean in its clinical manifestations and often difficult to recognize. It is clearly underdiagnosed. It has a tremendous variety of precipitants or causes. The complexity in categorization or classification makes it difficult to determine its morbidity or consequences. NCSE comprises many different illnesses, such that diagnosis and management are different for the many types, and the prognosis varies accordingly. Neurologists generally agree that episodes of NCSE should be avoided or treated, but the consequences and long-term risks are varied, difficult to ascertain, and controversial.
Synthesis and hepatic transport of strongly fluorescent cholephilic dipyrrinones.

A new class of highly fluorescent (φF 0.3−0.8) low molecular weight water-soluble cholephilic compounds has been synthesized in two steps from dipyrrinones. The dipyrrinone nitrogens are first bridged by reaction with 1,1‘-carbonyldiimidazole to form an N,N‘-carbonyldipyrrinone (3H,5H-dipyrrolo[1,2-c:2‘,1‘-f]pyrimidine-3,5-dione) nucleus, and a sulfonic acid group is then introduced at C(8) by reaction with concd H2SO4. The resulting sulfonated N,N‘-carbonyl-bridged dipyrrinones (“sulfoglows”) are isolated as their sodium salts. When the alkyl substituents of the lactam ring are lengthened from ethyl to decyl, sulfoglows become increasingly lipophilic while maintaining water solubility. Low molecular weight sulfoglows were rapidly excreted intact in both bile and urine after intravenous infusion into rats, but higher molecular weight sulfoglows were excreted more selectively in bile. Hepatobiliary excretion of sulfoglows was partially, but not completely, blocked in mutant rats deficient in the multidrug-...
Reason-based choice: A bargaining rationale for the attraction and compromise effects

Among the most important and robust violations of rationality are the attraction and the compromise effects. The compromise effect refers to the tendency of individuals to choose an intermediate option in a choice set, while the attraction effect refers to the tendency to choose an option that dominates some other options in the choice set. This paper argues that both effects may result from an individual’s attempt to overcome the difficulty of making a choice in the absence of a single criterion for ranking the options. Moreover, we propose to view the resolution of this choice problem as a cooperative solution to an intrapersonal bargaining problem among different selves of an individual, where each self represents a different criterion for choosing. We first identify a set of properties that characterize those choice correspondences that coincide with our bargaining solution, for some pair of preference relations. Second, we provide a revealed-preference foundation to our bargaining solution and characterize the extent to which these two preference relations can be uniquely identified. Alternatively, our analysis may be reinterpreted as a study of (interpersonal) bilateral bargaining over a finite set of options. In that case, our results provide a new characterization, as well as testable implications, of an ordinal bargaining solution that is previously discussed in the literature under the various names of fallback bargaining, unanimity compromise, Rawlsian arbitration rule, and Kant– Rawls social compromise.
Role of competition in restoring resource poor arid systems dominated by invasive grasses

Abstract Understanding the role competition intensity and importance play in directing vegetation dynamics is central to developing restoration strategies, especially in resource poor environments. We hypothesized 1) competition would be intense among invasive and native species, but 2) competition would be unimportant in explaining variation in target plant biomass and survivorship relative to other factors driving these variables. We performed a two year addition series field experiment to quantify competition intensity and importance. Densities of two invasive (cheatgrass and medusahead) and two native (Sandberg’s bluegrass and bluebunch wheatgrass) species were arranged in monocultures and mixtures of two, three and four species, producing varying total densities and species proportions. Multiple linear regression models predicting individual plant biomass and survivorship were developed. Based on biomass, competition intensity coefficients ranged from −0.38 to 0.63 with R 2 R 2
Nonlinear Aeroelasticity of a Very Flexible Blended-Wing-Body Aircraft

Blended-wing-body (BWB) aircraft with high-aspect-ratio wings is an important configuration for high-altitude long-endurance unmanned aerial vehicles (HALE UAV). Recently, Northrop Grumann created a wind tunnel model under the Air Force’s High Lift over Drag Active (HiLDA) Wing program to study the aeroelastic characteristics of blended-wing-body for a potential Sensorcraft concept. This paper presents a study on the coupled aeroelastic / flight dynamics stability and response of a BWB aircraft that is modified from the HiLDA experimental model. An effective method is used to model very flexible BWB vehicles based on a low-order aeroelastic formulation that is capable of capturing the important structural nonlinear effects and couplings with the flight dynamics degrees of freedom. A nonlinear strain-based beam finite element formulation is used. Finite-state unsteady subsonic aerodynamic loads are incorporated to be coupled with all lifting surfaces, including the flexible body. Based on the proposed model, body-freedom flutter is studied, and is compared with the flutter results with all or partial rigid-body degrees of freedom constrained. The applicability of wind tunnel aeroelastic results (where the rigid-body motion is limited) is discussed in view of the free flight conditions (with all 6 rigid-body degrees of freedom). Furthermore, effects of structural and aerodynamic nonlinearities as well as wing bending/torsion rigidity coupling on the stability and gust response are also studied in this paper.
Term disambiguation in natural language query for XML

Converting a natural language query sentence into a formal database query is a major challenge. We have constructed NaLIX, a natural language interface for querying XML data. Through our experience with NaLIX, we find that failures in natural language query understanding can often be dealt with as ambiguities in term meanings. These failures are typically the result of either the user's poor knowledge of the database schema or the system's lack of linguistic coverage. With automatic term expansion techniques and appropriate interactive feedback, we are able to resolve these ambiguities. In this paper, we describe our approach and present results demonstrating its effectiveness.
Recent research results in the aerodynamics of supersonic vehicles.

Wave drag, drag due to lift and aerodynamic interference effects on efficiency of supersonic cruise vehicle
Innovation and the Elasticity of Trade Volumes to Tariff Reductions

I study the implications of endogenous productivity choices ("innovation") on the effects of trade liberalization. I find that a model with innovation generates an elasticity of trade volumes to tariff reductions that is fifty percent larger than models without innovation, and consistent in magnitude to empirical estimates. To show this, I develop a new model of international trade with innovation, and calibrate it to data on Canada and the United States before the Free Trade Agreement. Feeding into the calibrated model the tariff drop that resulted from the agreement, the increase in the trade volumes is similar to that observed in the data. Without innovation, the change in trade volumes is considerably lower, and similar in magnitude to what existing models without innovation have found.
Multiplicativity of superoperator norms for some entanglement breaking channels

It is known that the minimal output entropy is additive for any product of entanglement breaking (EB) channels. The same is true for the Renyi entropy, where additivity is equivalent to multiplicativity of the 1→q norm for all q ≥ 1. In this paper we consider the related question of multiplicativity of the 2→q norm for q > 2 for entanglement breaking channels. We prove that multiplicativity holds in this case for certain classes of EB channels, including both the CQ and QC channels.
Dissipativity theory for nonnegative and compartmental dynamical systems with time delay

Nonnegative and compartmental dynamical system models are derived from mass and energy balance considerations that involve dynamic states whose values are nonnegative. These models are widespread in engineering and life sciences and typically involve the exchange of nonnegative quantities between subsystems or compartments wherein each compartment is assumed to be kinetically homogeneous. However, in many engineering and life science systems, transfers between compartments are not instantaneous and realistic models for capturing the dynamics of such systems should account for material in transit between compartments. Including some information of past system states in the system model leads to infinite-dimensional delay nonnegative dynamical systems. In this note, we develop dissipativity theory for nonnegative dynamical systems with time delay using linear storage functionals with linear supply rates. These results are then used to develop general stability criteria for feedback interconnections of nonnegative dynamical systems with time delay.
Designing truly one-sided MPI-2 RMA intra-node communication on multi-core systems

The increasing popularity of multi-core processors has made MPI intra-node communication, including the intra-node RMA (Remote Memory Access) communication, a critical component in high performance computing. MPI-2 RMA model includes one-sided data transfer and synchronization operations. Existing designs in popularly used MPI stacks do not provide truly one-sided intra-node RMA communication. They are built on top of two-sided send-receive operations, therefore suffering from overheads of two-sided communication and dependency on the remote side. In this paper, we enhance existing shared memory mechanisms to design truly one-sided synchronization. In addition, we design truly one-sided intra-node data transfer using two kernel based direct copy alternatives: basic kernel-assisted approach and I/OAT-assisted approach. Our new design eliminates the overhead of using two-sided operations and eliminates the involvement from the remote side. We also propose a series of benchmarks to evaluate various performance aspects over multi-core architectures (Intel Clovertown, Intel Nehalem and AMD Barcelona). The results show that the new design obtains up to 39% lower latency for small and medium messages and demonstrates 29% improvement in large message bandwidth. Moreover, it provides superior performance in terms of better scalability, reduced cache misses, higher resilience to process skew and increased computation and communication overlap. Finally, up to 10% performance benefits is demonstrated for a real scientific application AWM-Olsen.
A HYBRID REASONING MODEL FOR INDIRECT ANSWERS

This paper presents our implemented computational model for interpreting and generating indirect answers to Yes-No questions. Its main features are 1) a discourse-plan-based approach to implicature, 2) a reversible architecture for generation and interpretation, 3) a hybrid reasoning model that employs both plan inference and logical inference, and 4) use of stimulus conditions to model a speaker's motivation for providing appropriate, unrequested information. The model handles a wider range of types of indirect answers than previous computational models and has several significant advantages.
A bit-map-assisted dynamic queue protocol for multiaccess wireless networks with multiple packet reception

A novel network-assisted (signal processing based) medium access control (MAC) protocol known as the bit-map-assisted dynamic queue (BMDQ) is presented. The protocol is explicitly designed for a wireless slotted system with multiple packet reception (MPR) capability. In the proposed protocol, the traffic in the channel is viewed as a flow of transmission periods (TPs). Each TP has a bit-map (BM) slot at the beginning followed by a data transmission period (DP). The BM slot is reserved for user detection so that accurate knowledge of the active user set (AUS) can be obtained. Then, given the knowledge of the AUS and the channel MPR matrix, the number of users that can access the channel simultaneously in each packet slot in the DP is chosen to maximize the conditional throughput of every packet slot. Compared with other conventional and network-assisted MAC protocols, the proposed BMDQ protocol yields better performance. Its maximum steady-state throughput is close to the channel MPR capacity, and it can achieve the same throughput with lower traffic load and smaller delay. Performance issues are investigated analytically and via simulations.
The flight performance of the Galileo Orbiter USO

Radiometric tracking Doppler measurements of the signal transmitted by the Galileo spacecraft using an ultrastable oscillator (USO) as a frequency reference have been acquired by antennas of the NASA Deep Space Network between Dec. 1989 and Nov. 1991. The USO is a dual oven-controlled oscillator with an AT-cut quartz crystal (SiO/sub 1/) resonator. The output frequency of 19.124980 MHz is multiplied by 120 to produce the transmitted signal frequency (/spl sim/2.29 GHz). The average Allan deviations at 1-s and 10-s correlate well with spacecraft range, and fall as /spl tau//sup -1/. This is consistent with white PM noise dominating at these times scales due to the low SNR's expected from using the low gain antennas. The Allan deviations at 100-s and 1000-s agree with pre-flight USO stability results at these time scales. The Galileo USO appears to be healthy and functioning normally. >
The natural-rate hypothesis, the rational-expectations hypothesis, and the remarkable survival of non-market-clearing assumptions

Non-market-clearing models continue to dominate analysis of macroeconomic fluctuations and discussions of macroeconomic policy. This situation is remarkable because non-market-clearing assumptions seem to be inconsistent with the essential presumption of neoclassical economic analysis that market outcomes exhaust opportunities for mutually advantageous exchange. Non-market-clearing models apparently have survived because they have evolved to incorporate both the natural-rate hypothesis and the rational-expectations hypothesis and because the alternative "equilibrium" approach has failed empirically.This paper expands on these ideas and briefly discusses some of the problems that we face in attempting to evaluate empirically the recent vintage of non-market-clearing models. The main difficulties seem to involve accounting for shifts in the natural levels of real aggregates and specifying the timing of the past anticipations that determine the effects of current monetary policy.
FLOW AND STOCK EFFECTS OF LARGE-SCALE TREASURY PURCHASES

Using a panel of daily CUSIP-level data, we study the effects of the Federal Reserve’s program to purchase $300 billion of U.S. Treasury coupon securities announced and implemented during 2009. This program represented an unprecedented intervention in the Treasury market and thus allows us to shed light on the price elasticities and substitutability of Treasuries, preferred-habitat theories of the term structure, and the ability of large-scale asset purchases to reduce overall yields and improve market functioning. We find that, except for very long maturities, purchase operations caused an average decline in yields in the sector purchased of 3.5 basis points on the days when they occurred (the “flow effect” of the program). In addition, the program as a whole resulted in a persistent downward shift in the yield curve of as much as 50 basis points (the “stock effect”), with the largest impact on zero-coupon yields around the 5-year sector. The coefficient patterns generally support a view of segmentation or imperfect substitution within the Treasury market at the time of the program announcement and implementation.
Breaking and repairing optimistic fair exchange from PODC 2003

In PODC 2003, Park, Chong, Siegel and Ray [22] proposed an optimistic protocol for fair exchange, based on RSA signatures. We show that their protocol is totally breakable already in the registration phase: the honest-but-curious arbitrator can easily determine the signer's secret key.On a positive note, the authors of [22] informally introduced a connection between fair exchange and "sequential two-party multisignature schemes" (which we call two-signatures), but used an insecure two-signature scheme in their actual construction. Nonetheless, we show that this connection can be properly formalized to imply provably secure fair exchange protocols. By utilizing the state-of-the-art non-interactive two-signature of Boldyreva [6], we obtain an efficient and provably secure (in the random oracle model) fair exchange protocol, which is based on GDH signatures [9].Of independent interest, we introduce a unified model for non-interactive fair exchange protocols, which results in a new primitive we call verifiably committed signatures. Verifiably committed signatures generalize (non-interactive) verifiably encrypted signatures [8] and two-signatures, both of which are sufficient for fair exchange.
Inflation Regimes and Inflation Expectations

This paper examines the formation of expectations about future inflation over long horizons. A key issue that agents must confront is the possibility that the economic policy framework— especially the monetary policy regime—could change at some future date. Agents are likely to base inferences about possible future regimes on experience over many years and decades past. This aspect of expectations formation may explain why inflation premiums in long-term bond yields are higher in countries with a long history of high inflation. (JEL E52, E61, G12)
Equity Method Investments and Sell-Side Analysts' Information Environment

ABSTRACT: We study the joint effects of intercompany investing and reporting of equity method investments on the accuracy and dispersion of analysts' annual earnings-per-share (EPS) forecasts. We compare firm-year observations with and without equity method investments. We posit two non-mutually exclusive explanations for how equity method investments may affect analyst forecast properties. The Opacity Effect posits that the condensed equity method disclosures increase information asymmetry, increasing analysts' forecast errors and forecast dispersion. The Diversification Effect suggests that the diversification of the investor and its investee earnings streams enhances earnings predictability, decreasing analysts' forecast errors and forecast dispersion. Our findings are consistent with both effects operating in the analyst forecasting task. Additional analyses are consistent with the Opacity Effect dominating. This occurrence results, on net, in less accurate and more dispersed forecasts for firm-years ...
Financial development, financial structure, and domestic investment: International evidence

Does it matter for domestic investment whether a country’s financial system is bank based or stock-market based? This paper posits that financial intermediation affects domestic investment notably by alleviating financing constraints, allowing firms to increase investment in response to increased demand for output. The key result is that the structure of the financial system has no independent effect on investment, in the sense that it does not enhance the response of investment to changes in output, while financial development makes investment more responsive to output growth. Consequently, rather than promoting a particular type of financial structure, countries should implement policies that reduce transactions costs in financial intermediation and enforce creditor and investor rights. This will facilitate the development of banks and stock markets, which will stimulate domestic investment.
Theory of line-source radiation from a metal-strip grating dielectric-slab structure

This paper describes the fundamental theory of line source radiation from a source on a dielectric slab backed by a metal-strip grating. A continuous phased-array (CPA) method is applied to treat the analytic and numerical problems of antenna interaction with periodic structures. Both TE and TM mode cases for a one-dimensional strip grating are investigated. It is found that the strip grating on the dielectric surface may result in surface wave elimination and may also be used to support leaky waves. It is shown that high-efficiency and high-gain antennas on a dielectric substrate are possible with such metal-strip gratings.
A multiresolution approach for all-digital HDTV

The authors investigate the feasibility of a fully digital HDTV (high-definition television) production, processing, coding, and transmission standard that will be a true alternative to analog television. Such a television system is defined as a medium-range technological goal and will have a direct impact on various technologies, including computers, telecommunications, and high-speed VLSI. The authors describe research directions as well as current progress, especially with respect to hierarchical representations and coding methods, nonlinear interpolation techniques, and joint source-channel coding for digital channels. Multiresolution techniques are central to the authors' approach, because they are useful for compression, joint source-channel coding, and compatibility. >
Multihop lightwave networks: a comparison of store-and-forward and hot-potato routing

The achievable aggregate capacity for a variant of the basic multihop approach in which minimum distance store-and-forward routing is replaced by a hot-potato routing algorithm is determined. With hot-potato routing, all packets simultaneously arriving at a given node and not intended for reception at that node are immediately placed onto the outbound links leaving that node; if two or more packets contend for the same outgoing link to achieve a minimum distance routing, then all but one will be misrouted to links which produce longer paths to the eventual destination. Attention is confined to the development of an analytical methodology for finding the probability distribution of the number of hops with hot potato routing for symmetric networks under uniform traffic load. Results show that the maximum throughput achievable with hot-potato routing can be as low as 25% of that for store-and-forward routing, and that the relative degradation increases as the number of nodes grows larger. This implies that the link speed up needed to produce a significant overall capacity advantage with hot potato should be at least a factor of 10. >
A method for calculating probabilities of fitness consequences for point mutations across the human genome

We describe a new computational method for estimating the probability that a point mutation at each position in a genome will influence fitness. These 'fitness consequence' (fitCons) scores serve as evolution-based measures of potential genomic function. Our approach is to cluster genomic positions into groups exhibiting distinct 'fingerprints' on the basis of high-throughput functional genomic data, then to estimate a probability of fitness consequences for each group from associated patterns of genetic polymorphism and divergence. We have generated fitCons scores for three human cell types on the basis of public data from ENCODE. In comparison with conventional conservation scores, fitCons scores show considerably improved prediction power for cis regulatory elements. In addition, fitCons scores indicate that 4.2-7.5% of nucleotides in the human genome have influenced fitness since the human-chimpanzee divergence, and they suggest that recent evolutionary turnover has had limited impact on the functional content of the genome.