cssi/SciSciGPT-SciSciNet huggingface dataset:
Student Performance and Perceptions in a Web-Based Competitive Computer Simulation

Computer simulations have implications across disciplines and with learners at all levels. By requiring learners to develop and apply knowledge and skills in interactive changing environments, they encourage deeper levels of learning. Additionally, simulations have been shown to be particularly effective at teaching complicated concepts that depend on the ability to understand interrelationships, strategize, make predictions, analyze and evaluate, and engage in multi-faceted decision making. In order to help students gain a deeper understanding of key business concepts, encourage critical thinking and decision making, foster collaboration and critical discourse, and encourage the application of concepts into real world business practices, the University of Maryland Eastern Shore, a minority serving institution, decided in 2004 to introduce a series of competitive webbased simulations at key junctures throughout the curriculum but focused primarily in the course Strategic Management. The simulation selected covers topics such as Strategy & T actics, Policy, Production, Accounting, Marketing, Finance, Quality control, Human resources, Leadership, and T eamwork and involves students competing in teams against other teams. In order to assess the effectiveness of the simulation, a research protocol was introduced that included the administration of student surveys as well as the collection of performance data. The findings indicate that students overwhelmingly felt that the simulation helped them understand the application of key concepts and learn the decision making process that occurs in professional business practice. The examination of student performance data gathered in this study, with consideration given to the strong levels of student satisfaction, encouraged the authors to postulate based on the high success rates of this student population, which traditionally underperforms in more traditional mode of assessments, that simulations may serve as an equalizer that offers all students, from low to high achievers, an opportunity to succeed and that competitive web-based simulations enhance the overall educational and personal development experiences of minority students enrolled in higher education business programs.
Laser‐induced etching

Laser‐induced etching of metals, semiconductors, and other inorganic materials can be etched by ablation, localized heating to enhance a thermally activated chemical reaction, or photogeneration of a good etchant from a less reactive precursor. In addition, semiconductors can be etched following photoexcitation of the surface to produce free carrierrs. The advantages and disadvantages of these four approaches to laser‐induced etching are reviewed in this paper.
Alcohol-related crime among college students: a review of research and fruitful areas for future work

College and alcohol are a potent mix. This paper reviews what is known and unknown about college students’ involvement in alcohol-related crime as both offenders and victims. There are three types of alcohol-related crime: psychopharmacological; economic compulsive; and systemic. Research on college students, however, has focused entirely on the first type. Why are the latter two types untouched in the literature? After reviewing research on alcohol-involved psychopharmacological crime among college students, we address this question by drawing on Lewis & Lewis’ taxonomy of ‘negative evidence.’ We outline and assess reasons for the dearth of information on these topics, and draw on these explanations to suggest fruitful areas for future research.
Qualitative MDPs and POMDPs: an order-of-magnitude approximation

We develop a qualitative theory of Markov Decision Processes (MDPS) and Partially Observable MDPS that can be used to model sequential decision making tasks when only qualitative information is available. Our approach is based upon an order-of-magnitude approximation of both probabilities and utilities, similar to e-semantics. The result is a qualitative theory that has close ties with the standard maximum-expected-utility theory and is amenable to general planning techniques.
Learning, Information Extraction and the Web

Significant progress has been made recently in semi-supervised learning algorithms that require less labeled training data by utilizing unlabeled data. Much of this progress has been made in the context of natural language analysis (e.g., semi-supervised learning for named entity recognition and for relation extraction). This talk will overview progress in this area, present some of our own recent research, and explore the possibility that now is the right time to mount a community-wide effort to develop a never-ending natural language learning system.
The first ten years of Swift supernovae

Abstract The Swift Gamma Ray Burst Explorer has proven to be an incredible platform for studying the multiwavelength properties of supernova explosions. In its first ten years, Swift has observed over three hundred supernovae. The ultraviolet observations reveal a complex diversity of behavior across supernova types and classes. Even amongst the standard candle type Ia supernovae, ultraviolet observations reveal distinct groups. When the UVOT data is combined with higher redshift optical data, the relative populations of these groups appear to change with redshift. Among core-collapse supernovae, Swift discovered the shock breakout of two supernovae and the Swift data show a diversity in the cooling phase of the shock breakout of supernovae discovered from the ground and promptly followed up with Swift. Swift observations have resulted in an incredible dataset of UV and X-ray data for comparison with high-redshift supernova observations and theoretical models. Swift's supernova program has the potential to dramatically improve our understanding of stellar life and death as well as the history of our universe.
Beyond Human, Avatar as Multimedia Expression

The Avatar, the representation of the user in three-dimensional chat environments, serves as a visual identifier for the user and through gestures/costumes acts as a means of expression for the user. The Avatar also serves as a point through which the user receives information and manipulates the environment. Abstracted into programming terminology, the Avatar is not a humanoid representation endowed with gestural expression, but a four dimensional point (3D & time) for data exchange. Accepting this abstraction of the Avatar opens the door to a world of simple, yet previously unthinkable, possibilities for expressive communication.
Moving image restoration and registration

A new method for moving image restoration and registration is established. The observations are sequences of low-resolution, possibly undersampled, discrete frames. The result is a restored high-resolution image. The restoration part is attractive for the purpose of real time implementation since the computation consists of only a few complex operations per pel of the resultant high resolution image. Tests on a class of waveforms with different bandwidths show that the performance is superior to that of the cubic spline technique in terms of the signal to noise ratio. The registration part has two new features: 1) The relative shifts of several frames can be estimated in one process. 2) The estimate is accruate even if the observation frames are severely undersampled, so long as the number of frames available is big enough.
MOTIVATION AND INCENTIVES IN EDUCATION: EVIDENCE FROM A SUMMER READING EXPERIMENT

Abstract Policymakers and economists have expressed support for the use of incentives in educational settings. In this paper, rather than asking whether incentives work, we focus on a different question: For whom and under what conditions do incentives work? This question is particularly important because incentives’ promise relies on the idea that they might take the place of some cognitive failing or set of preferences that otherwise would have led students to make choices with large long-term benefits. In this paper, we explore whether that is the case. In the context of a summer reading program called Project READS, we test whether responsiveness to incentives is positively or negatively related to the student's baseline level of motivation to read. As a part of the program, elementary school students are mailed books weekly during the summer. We implemented this book-mailing program as a randomized experiment with three treatment arms. Students in the first treatment arm were mailed books as a part of the standard Project READS program. Students in the second treatment arm were mailed books as a part of Project READS, and were also offered an incentive to read the books they were mailed. Students in the third experimental group served as a control and were given books after posttesting occurred in the fall. We find that, if anything, more motivated readers are more responsive to incentives to read, suggesting that to the extent that incentives are effective, they may not effectively target the students whose behavior they are intended to change.
RECONCILING BILATERAL TRADE DATA FOR USE IN GTAP

Bilateral trade flows are reported by both importers and exporters. Large discrepancies in reported import/export trade flows can be found when these two reports are compared. The GTAP database requires consistency between the export flow and its corresponding import flow for all partner pairs. Therefore, bilateral trade data in its reported form cannot be directly used for GTAP. Various methods can be used to produce a consistent set of bilateral trade flows. However, achieving consistency alone does not necessarily provide credible trade flows. Matrix balancing using trade totals published by international agencies is not appropriate since these totals are not reconciled but are simply totals from country-reported flows. A method is developed with the aim of extracting the most reliable reported trade flows from reported import and export flows. Specific examples are used to illustrate how discrepancies can result from reporting errors and transport margins. Evidence is shown indicating that discrepancies often arise from erroneous reporting by one of the partners. Systematic reporting errors associated with a reporter can be measured by the share of consistent transactions with partners. The most reliable reported flows are selected based on credibility of reporters. The source of international bilateral trade for GTAP is United Nations COMTRADE database. It contains the complete set of countries in the world and the set of commodities covering total merchandise trade. Since errors in reporting are country-commodity specific, data is processed at the individual country and SITC 4-digit level before aggregating to the 30-region 31- merchandise trade commodity database in version 3 of the GTAP data base.
In vivo Time-Lapse Fluorescence Imaging of Individual Retinal Ganglion Cells in Mice

We have developed a technique that permits time-lapse imaging of retinal ganglion cells (RGCs), their dendritic arbors and their axons in mammals in vivo. This technique utilizes a standard confocal laser scanning microscope, transgenic mice that express yellow fluorescent protein (YFP) in a subset of RGCs and survival anesthesia techniques. The same individual RGCs with their dendritic arbors and axons were multiply imaged in vivo in both adult and juvenile mice. Additionally, the same RGC that was imaged in vivo could then be located and imaged in fixed retinal whole mount preparations. This novel technique has many potential applications.
Geometric compatibility of IceCube TeV-PeV neutrino excess and its galactic dark matter origin

We perform a geometric analysis for the sky map of the IceCube TeV-PeV neutrino excess and test its compatibility with the sky map of decaying dark matter signals in our galaxy. We have found that a galactic decaying dark matter component in general improve the goodness of the fit of our model, although the pure isotropic hypothesis has a better fit than the pure dark matter one. We also consider several representative decaying dark matter, which can provide a good fit to the observed spectrum at IceCube with a dark matter lifetime of around 12 orders of magnitude longer than the age of the universe.
Hierarchical pointer analysis for distributed programs

We present a new pointer analysis for use in shared memory programs running on hierarchical parallel machines. The analysis is motivated by the partitioned global address space languages, in which programmers have control over data layout and threads and can directly read and write to memory associated with other threads. Titanium, UPC, Co-Array Fortran, X10, Chapel, and Fortress are all examples of such languages. The novelty of our analysis comes from the hierarchical machine model used, which captures the increasingly hierarchical nature of modern parallel machines. For example, the analysis can distinguish between pointers that can reference values within a thread, within a shared memory multiprocessor, or within a network of processors. The analysis is presented with a formal type system and operational semantics, articulating the various ways in which pointers can be used within a hierarchical machine model. The hierarchical analysis has several applications, including race detection, sequential consistency enforcement, and software caching. We present results of an implementation of the analysis, applying it to data race detection, and show that the hierarchical analysis is very effective at reducing the number of false races detected.
The p-adic Integers as Final Coalgebra

We express the classical p-adic integers \(\hat{\mathbb {Z}}_p\), as a metric space, as the final coalgebra to a certain endofunctor. We realize the addition and the multiplication on \(\hat{\mathbb {Z}}_p\) as the coalgebra maps from \(\hat{\mathbb {Z}}_p\times \hat{\mathbb {Z}}_p\).
Hot electron reliability and ESD latent damage

The authors present a study of the impact of noncatastrophic electrostatic-discharge (ESD) stress on hot-electron reliability as well as the effect of hot electron (HE) injection on ESD protection threshold. It is found that there is a factor of two to four deterioration in hot-electron reliability after low-level ESD stress. These two effects can be viewed as similar in that HE is a low-current long-time process and ESD is a high-current short-time process. Therefore the techniques for characterizing hot-electron degradation have been applied to quantify damage due to ESD stress. This technique shows electrical evidence of current filaments during an ESD. >
Dual Superconductivity, Effective String Theory, and Regge Trajectories

We show how an effective field theory of long distance QCD, describing a dual superconductor, can be expressed as an effective string theory of superconducting vortices. We evaluate the semiclassical expansion of this effective string theory about a classical rotating string solution in any spacetime dimension D. We show that, after renormalization, the zero point energy of the string fluctuations remains finite when the masses of the quarks on the ends of the string approach zero. For D = 26 the semiclassical energy spectrum of the rotating string formally coincides with that of the open string in classical Bosonic string theory. However, its physical origin is different. It is a semiclassical spectrum of an effective string theory valid only for large values of the angular momentum. For D = 4 the first semiclassical correction adds the constant 1/12 to the classical Regge formula for the angular momentum of mesons on the leading Regge trajectory. The excited vibrational modes of the rotating string give rise to daughter Regge trajectories determining the spectrum of hybrid mesons.
A Graph Reduction Step Preserving Element-Connectivity and Applications

Given an undirected graph G = (V ,E ) and subset of terminals T *** V , the element-connectivity *** *** G (u ,v ) of two terminals u ,v *** T is the maximum number of u -v paths that are pairwise disjoint in both edges and non-terminals V *** T (the paths need not be disjoint in terminals). Element-connectivity is more general than edge-connectivity and less general than vertex-connectivity. Hind and Oellermann [18] gave a graph reduction step that preserves the global element-connectivity of the graph. We show that this step also preserves local connectivity, that is, all the pairwise element-connectivities of the terminals. We give two applications of the step to connectivity and network design problems: First, we show a polylogarithmic approximation for the problem of packing element-disjoint Steiner forests in general graphs, and an O (1)-approximation in planar graphs. Second, we find a very short and intuitive proof of a spider-decomposition theorem of Chuzhoy and Khanna [10] in the context of the single-sink k -vertex-connectivity problem. Our results highlight the effectiveness of the element-connectivity reduction step; we believe it will find more applications in the future.
Transforming pseudo-triangulations

We study the problem of transforming pseudotriangulations in the plane. We show that a pseudo-triangulation with n vertices can be transformed into another one using O(n log n) flips only. This improves the previous bound O(n2) [3]. We present an algorithm for computing a transformation between two pseudo-triangulations in O((f + n) log n) time where f is the number of flips.
Delegated law enforcement and noncooperative behavior

Law enforcement is generally carried out by delegated authority. Policymakers (the legislature or the executive administration) delegate enforcement of laws and regulations to public or private agencies. Policymakers do not precommit to enforcement effort. Instead, they enunciate policy goals, appropriate funds, and specify broad objectives for the enforcement agency, which typically has considerable discretion in carrying out its assigned task. This article addresses two significant problems arising from the delegation of law enforcement. First, the policymaker's problem of designing incentives to induce efficient performance by the enforcement agency is examined. Second, the effect of delegation on the enforcer's strategic interaction with potential offenders is specified. The observability of law enforcement effort plays an important role in the
International Contagion: Implications for Policy

The current debate on financial contagion is motivated by a number of policy questions. What can we do to prevent contagion? Should we do anything about it? In this chapter we attempt to identify and evaluate the public policy implications of recent research on financial contagion.
Expectations, Learning, and Discretionary Policymaking

When people's policy forecasts are generated by exact replication of the policymaker's decision problem, present and past policy has no effect on expectations of future policy. However, when people's policy forecasts are based on the policymaker's present and past actions, for example through learning and estimation of variables or parameters, policy affects expectations of future policy, and the time-consistent solution improves. Therefore, a successful policymaker needs to know how present policy affects people's policy expectations.
Optimal switching policies using coarse timesteppers

We present a computer-assisted approach to approximating coarse optimal switching policies for systems described by microscopic/stochastic evolution rules. The "coarse timestepper' constitutes a bridge between the underlying kinetic Monte Carlo simulation and traditional, continuum numerical optimization techniques formulated in discrete time. The approach is illustrated through a simplified kinetic Monte Carlo simulation of NO reduction on a Pt catalyst: a switch between two coexisting stable steady states is implemented by minimal manipulation of a system parameter.
First-Principles Theories of Piezoelectric Materials

Piezoelectrics have long been studied using parameterized models fit to experimental data, starting with the work of Devonshire in 1954. [1] Much has been learned using such approaches, but they can also miss major phenomena if the materials properties are not well understood, as is exemplified by the realization that low-symmetry monoclinic phases are common around morphotropic phase boundaries, which was missed completed by low-order Devonshire models, and can only appear in higher order models. [2] In the last 15 years, a new approach has developed using first-principles computations, based on fundamental physics, with no essential experimental input other than the desired chemistry (nuclear charges). First-principles theory laid the framework for a basic understanding of the origins of ferroelectric behavior [3-7] and piezoelectric properties. [8-11] The range of properties accessible to theory continues to expand as does the accuracy of the predictions. We are moving towards the ability to design materials of desired properties computationally. Here we review some of the fundamental developments of our understanding of piezoelectric material behavior and ability to predict a wide range of properties using theoretical methods. This is not meant as a review of the literature. Comprehensive reviews of the literature of theoretical studies of ferroelectrics are given by Resta [12] and Rabe and Ghosez. [13]
Long arithmetic progressions in sumsets: Thresholds and bounds

l∗A = {a1 + · · ·+ al|ai ∈ Ai, ai = aj}. Among the most well-known results in all of mathematics are Vinogradov’s theorem, which says that 3P (P is the set of primes) contains all sufficiently large odd numbers, and Waring’s conjecture (proved by Hilbert, Hardy and Littlewood, Hua, and many others), which asserts that for any given r, there is a number l such that l∗Nr (N denotes the set of rth powers) contains all sufficiently large positive integers (see [29] for an excellent exposition concerning these results). In recent years, a considerable amount of attention has been paid to the study of finite sumsets. Given a finite set A and a positive integer l, the natural analogue of Vinogadov-Waring results is to show that under proper conditions, the sumset lA (l∗A) contains a long arithmetic progression. Let us assume that A is a subset of the interval [n] = {1, . . . , n}, where n is a large positive integer. The concrete problem we would like to address is to estimate the minimum length of the longest arithmetic progression in lA (l∗A) as a function of l, n, and |A|. We denote this function by f(|A|, l, n) (f∗(|A|, l, n)), following the notation in [13]. Many estimates for f(|A|, l, n) have been discovered by Bourgain, Freiman, Halberstam, Green, Ruzsa, and Sarkozy (see Section 3), but most of these results focus on sets with very high density, namely |A| is close to n. Estimating f∗(|A|, l, n) seems much harder, and not much was known prior to our study.
PHOTOACOUSTIC DETECTION METHODS FOR CHARACTERIZING LASER IRRADIATION AND RECRYSTALLIZATION OF SEMICONDUCTORS

The use of photoacoustic detection is discussed as a technique for monitoring laser heating and for characterizing implantation and recrystallization of semiconductors via optical absorption. Preliminary results are reported for laser heating of Ge. A method is proposed for signal processing to enable measurement of optical absorption coefficient changes due to implantation and recrystallization without a background signal from the unimplanted region of the semiconductor.
Energetics in MRI driven Turbulence

In these proceedings we present recent efforts to understand the energetics of magneto‐hydrodynamic (MHD) turbulence driven by the magneto‐rotational instability (MRI). These studies are carried out in the local (shearing box) approximation using the Athena simulation code. Athena is a higher order Godunov algorithm based on the piecewise parabolic method (PPM), the corner transport upwind (CTU) integration algorithm, and the constrained transport (CT) algorithm for evolving the magnetic field. This algorithm is particularly suited for these studies owing to the conservation properties of a Godunov scheme and the particular implementation of the shearing box source terms used here. We present a variety of calculations which may be compared directly to previously published results and discuss them in some detail. The only significant discrepancy found between the results presented here and in the published literature involves the turbulent heating rate. We observe the presence of recurrent channel solutions in calculations involving a mean vertical magnetic field and the associated time lag between the energy injection and thermalization rate. We also present the results of a shearing box calculation which includes an optically thin radiative term with a cooling rate selected to match the turbulent heating rate. Some properties which we find uniformly present in all of the calculations presented here are compressible fluctuations, spiral waves and weak shocks. It is found that these compressible modes dominate the temporal fluctuations in the probability distribution functions for most of the thermodynamic variables; only the specific entropy is relatively immune to their effects.In these proceedings we present recent efforts to understand the energetics of magneto‐hydrodynamic (MHD) turbulence driven by the magneto‐rotational instability (MRI). These studies are carried out in the local (shearing box) approximation using the Athena simulation code. Athena is a higher order Godunov algorithm based on the piecewise parabolic method (PPM), the corner transport upwind (CTU) integration algorithm, and the constrained transport (CT) algorithm for evolving the magnetic field. This algorithm is particularly suited for these studies owing to the conservation properties of a Godunov scheme and the particular implementation of the shearing box source terms used here. We present a variety of calculations which may be compared directly to previously published results and discuss them in some detail. The only significant discrepancy found between the results presented here and in the published literature involves the turbulent heating rate. We observe the presence of recurrent channel solution...
Stochastic reactive power management in microgrids with renewables

Distribution microgrids are being challenged by reverse power flows and voltage fluctuations due to renewable generation, demand response, and electric vehicles. Advances in photovoltaic (PV) inverters offer new opportunities for reactive power management provided PV owners have the right investment incentives. In this context, reactive power compensation is considered here as an ancillary service. Accounting for the increasing time-variability of distributed generation and demand, a stochastic reactive power compensation scheme is developed. Given uncertain active power injections, an online reactive control scheme is devised. This scheme is distribution-free and relies solely on power injection data. Reactive injections are updated using the Lagrange multipliers of a second-order cone program. Numerical tests on an industrial 47-bus microgrid and the residential IEEE 123-bus feeder corroborate the reactive power management efficiency of the novel stochastic scheme over its deterministic alternative, as well as its capability to track variations in solar generation and household demand.
On a weak type (1,1) inequality for a maximal conjugate function

Throughout this paper, N denotes a fixed but arbitrary positive integer, T denotes the circle group, and T denotes the product of N copies of T. The normalized Lebesgue measure on T will be symbolized by P . For a measurable function f , we let ‖f‖1 = supy>0 yλf(y) where λf(y) = P ( {x ∈ T : |f(x)| > y} ) . The integers will be denoted by Z and the complex numbers by C. Let Fn = σ(e iθ1 , e2, . . . , en) denote the σ-algebra on T generated by the first n coordinate functions. For f ∈ L1(T), the conditional expectation of f with respect to Fn will be denoted E(f |Fn). Let d0(f) = E(f |F0) = ∫
HEALTH INSURANCE, FERTILITY, AND THE WANTEDNESS OF PREGNANCIES: EVIDENCE FROM MASSACHUSETTS

Health insurance reform in Massachusetts lowered the financial cost of both pregnancy (by increased coverage of pregnancy-related medical events) and pregnancy prevention (by increasing access to reliable contraception and family planning). We examine fertility responses for women of childbearing age in Massachusetts and, on net, find no effect from increasing health insurance coverage. This finding, however, masks substantial heterogeneity. For married women aged 20 to 34 – who have high latent fertility and for whom pregnancies are typically wanted – fertility increased by approximately 1 percent. For unmarried women in the same age range – for whom pregnancies are typically unwanted – fertility declined by 9 percent. Fertility rates changed very little for other groups, in part because of low latent fertility or minimal gains in insurance coverage. Pregnancy wantedness increased in the aggregate through a combination of increasing wanted births and decreasing unwanted births.
Kinematics and Inertial Effects in Locust Flapping Wings

In the present study, inertial forces and kinematics of wings of locusts, Schistocerca americana, were investigated experimentally. The developed experimental setup includes freshly extracted hindwings and forewings, a mechanical transmission producing pitching and flapping, a vacuum chamber, and a high-speed video system. Flapping angle amplitudes determined at the middle section are practically the same in air and in vacuum in both forewings and hindwings. Pitching amplitudes in the root and in the middle section of hindwing differ by up to 50 % due to torsional deformation or twist. In air, the average twist angles are 3° and 17° in forewings and hindwings, respectively. Amplitudes of twist angle are higher in vacuum, especially at relatively high flapping frequencies. Inertial forces are calculated based on a rigid-body model of a wing with prescribed displacements. The 5-segment mesh for hindwings and 2-segment mesh for forewings provide accurate determination of inertial forces. Amplitudes of the fifth harmonic in accelerations in air are substantially smaller than in vacuum and, therefore, inertial forces in air are about 30 % smaller than those in vacuum. Thus, aerodynamic loads suppressed high-frequency component in wing oscillations resulting in substantially smaller inertial forces in air.
Rewriting flash memories by message passing

This paper constructs WOM codes that combine rewriting and error correction for mitigating the reliability and the endurance problems in flash memory.We consider a rewriting model that is of practical interest to flash applications where only the second write uses WOM codes. Our WOM code construction is based on binary erasure quantization with LDGM codes, where the rewriting uses message passing and has potential to share the efficient hardware implementations with LDPC codes in practice. We show that the coding scheme achieves the capacity of the rewriting model. Extensive simulations show that the rewriting performance of our scheme compares favorably with that of polar WOM code in the rate region where high rewriting success probability is desired. We further augment our coding schemes with error correction capability. By drawing a connection to the conjugate code pairs studied in the context of quantum error correction, we develop a general framework for constructing error-correction WOM codes. Under this framework, we give an explicit construction of WOM codes whose codewords are contained in BCH codes
Efficient reconfigurable logic circuits for matching complex network intrusion detection patterns

This paper presents techniques for designing pattern matching circuits for complex regular expressions, such as those found in network intrusion detection patterns. We have developed a pattern-matching co-processor that supports all the pattern matching functions of the Snort rule language [3]. In order to achieve maximum pattern capacity and throughput, the design focuses on minimizing circuit area while maintaining high clock speed. Using our approach, we are able to store the entire current Snort rule database consisting of over 1,500 rules and 17,000 characters into a single one-million-gate FPGA while comparing all patterns against traffic at gigabit rates.
Multifrequency Radio Properties of the Crab Pulsar

During a single Arecibo observation in 1981 of the Crab pulsar, a profile at 4.7 GHz was recorded which appeared to contain additional components and an interpulse (IP) shifted to earlier phase. The experiment was continued at the VLA, taking advantage of its phased array mode to form a synthesized beam, which resolves out the bright Crab Nebula background. Observations were conducted between February 9 and May 27, 1994, at 0.33, 1.4, 4.9, and 8.4 GHz. Additional radio profiles presented here were recorded at Arecibo (0.43, 0.6, and 4.7GHz) and Effelsberg (2.7GHz) by Hankins & Fowler (unpublished). In Figure 1 we have plotted a summary of normalized profiles from several radio frequencies and infrared. The VLA profiles are time aligned, while the rest are aligned to the main pulse (MP). A new component (labeled LFC) appears 36° ahead of the MP between 0.6 and 4.9 GHz, not coincident with the position of the precursor, and with a spectral index similar to that of the MP. The MP disappears at 8.4 GHz, probably due to spectral effects. The IP appears to undergo a transition in phase and flux, disappearing at 2.7 GHz and reappearing 10° earlier at 4.7 GHz with a radically different spectral index. Two high radio frequency components (labeled HFC1 and HFC2) appear at 4.9 and 8.4 GHz, and possibly at the noise level at 1.4 GHz. They have flatter spectral indices than the MP and IP and their centroid phase changes with respect to the MP – moving to later phase with increasing frequency. The infrared profile exhibits a “bump”, or third component near the same phase as HFC1 and HFC2.
Johnson Photometry and Its Descendants

This paper will explore the implementation of the photometric system established by Harold Johnson and colleagues, and the accuracies that have been achieved through its use.
Boltzmann's Approach to Statistical Mechanics

In the last quarter of the nineteenth century, Ludwig Boltzmann explained how irreversible macroscopic laws, in particular the second law of thermodynamics, originate in the time-reversible laws of microscopic physics. Boltzmann’s analysis, the essence of which I shall review here, is basically correct. The most famous criticisms of Boltzmann’s later work on the subject have little merit. Most twentieth century innovations —such as the identification of the state of a physical system with a probability distribution (o on its phase space, of its thermodynamic entropy with the Gibbs entropy of (o, and the invocation of the notions of ergodicity and mixing for the justification of the foundations of statistical mechanics—are thoroughly misguided.
Purposive Diversification and Economic Performance

Introduction: An overview Part I. Static Efficiency and the Diversified Firm: 1. The multimarket firm 2. Theories linking multimarket contact and market power 3. Diversifying mergers and strategic congruence 4. Multimarket contact and resource allocation 5. The market power of diversifed oligopolists Part II. Firm and Industry Effects Versus Traditional Models: 6. Profitability effects 7. R & D intensity effects Part III. Dynamic Efficiency and the Diversified Firm: 8. Theories linking diversification and the R & D investment 9. Diversification of R & D and productivity 10. Multimarket rivalry and R & D intensity 11. Research diversity induced by rivalry Part IV. Industrial Policy: 12. Diversification versus cooperation in R & D 13. From cooperative research to cooperative production 14. Damoclean taxation and innovation Afterword: perspectives through time and across countries Notes References Index.
Search for Oxygen in Cool DQ White Dwarf Atmospheres

The existence of carbon in cool He white dwarf (WD) atmospheres has been known for a relatively long time[5]. The presence of carbon in these atmospheres is explained by convective dredge up of interior carbon [6]. Pelletier et al. (1986) presented the first detailed calculations of this process and showed that carbon diffuses upwards from the core into the base of the He-rich envelope where it can be dredged up by a surface convection zone. As the temperature of the star decreases, more carbon diffuses upward, and the base of convection zone moves deeper into the star, further enriching the surface layers with carbon [2]. The diffusion time scales of C and O do not differ by large amounts, and are found to be essentially the same for some models [3]. We expect all non-interacting WDs with 0.45 < M wd /M ⊙ < 1.1 to have C/O cores. Since there is oxygen in these cores, there is a priori no reason to prevent the dredge up of oxygen as well as that of carbon. This paper reports new infrared spectroscopic observations of DQ WDs searching for oxygen and describes model atmospheres for these stars.
The Trade-off between Bioenergy and Emissions When Land Is Scarce

Agricultural biofuels require the use of scarce land, and this land has opportunity cost. We explore the objective function of a social planner who includes a land constraint in the optimization decision to minimize environmental cost. The results show that emissions should be measured on a per acre basis. Conventional agricultural life cycle assessments for biofuels report carbon emissions on a per gallon basis, thereby ignoring the implications of land scarcity and implicitly assuming an infinite supply of the inputs needed for production. Switchgrass and corn are then modeled as competing alternatives to show how the inclusion of a land constraint can influence life cycle rankings and alter policy conclusions.
A case study in complexity estimation: towards parallel branch-and-bound over graphical models

We study the problem of complexity estimation in the context of parallelizing an advanced Branch and Bound-type algorithm over graphical models. The algorithm's pruning power makes load balancing, one crucial element of every distributed system, very challenging. We propose using a statistical regression model to identify and tackle disproportionally complex parallel subproblems, the cause of load imbalance, ahead of time. The proposed model is evaluated and analyzed on various levels and shown to yield robust predictions. We then demonstrate its effectiveness for load balancing in practice.
The Intensity of Competition in the Hotelling Model: A New Generalization and Applications

I develop a simple Hotelling model which relates the distribution of consumer preferences to the intensity of competition. I impose two properties, mean preserving spread (MPS) and monotone likelihood ratio property (MLRP), on distribution functions. These properties provide a way to represent the intensity of competition in the Hotelling model. Market competition is less intense as the distribution is dispersed in that the MPS raises firms' equilibrium prices. This approach can describe how the intensity of competition influences the effects of firm's various strategies, which has been largely neglected in most papers. Non-uniform distributions can reverse some well-known results derived under the uniform distribution dramatically. They also allow us to discover new results that the uniform distribution could not demonstrate. As examples, I study three issues such as incentives for innovation, preference based price discrimination, and incentives for information sharing.
Definition of MHC Supertypes Through Clustering of MHC Peptide-Binding Repertoires

Identification of peptides that can bind to major histocompatibility complex (MHC) molecules is important for anticipation of T-cell epitopes and for the design of epitope-based vaccines. Population coverage of epitope vaccines is, however, compromised by the extreme polymorphism of MHC molecules, which is in fact the basis for their differential peptide binding. Therefore, grouping of MHC molecules into supertypes according to peptide-binding specificity is relevant for optimizing the composition of epitope-based vaccines. Despite the fact that the peptide-binding specificity of MHC molecules is linked to their specific amino acid sequences, it is unclear how amino sequence differences correlate with peptide-binding specificities. In this chapter, we detail a method for defining MHC supertypes based on the analysis and subsequent clustering of their peptide-binding repertoires.
Information dissemination via random walks in d-dimensional space

We study a natural information dissemination problem for multiple mobile agents in a bounded Euclidean space. Agents are placed uniformly at random in the d-dimensional space {-n,...,n}d at time zero, and one of the agents holds a piece of information to be disseminated. All the agents then perform independent random walks over the space, and the information is transmitted from one agent to another if the two agents are sufficiently close. We wish to bound the total time before all agents receive the information (with high probability). Our work extends Pettarin et al's work [10], which solved the problem for d ≤ 2. We present tight bounds up to polylogarithmic factors for the case d = 3. (While our results extend to higher dimensions, for space and readability considerations we provide only the case d = 3 here.) Our results show the behavior when d ≥ 3 is qualitatively different from the case d ≤ 2. In particular, as the ratio between the volume of the space and the number of agents varies, we show an interesting phase transition for three dimensions that does not occur in one or two dimensions.
Accretion disc wind variability in the states of the microquasar GRS 1915+105

Continuing our study of the role and evolution of accretion disc winds in the microquasar GRS 1915+105, we present high-resolution spectral variability analysis of the β and γ states with the Chandra High-Energy Transmission Grating Spectrometer. By tracking changes in the absorption lines from the accretion disc wind, we find new evidence that radiation links the inner and outer accretion discs on a range of time-scales. As the central X-ray flux rises during the high-luminosity γ state, we observe the progressive overionization of the wind. In the β state, we argue that changes in the inner disc leading to the ejection of a transient ‘baby jet’ also quench the highly ionized wind from the outer disc. Our analysis reveals how the state, structure and X-ray luminosity of the inner accretion disc all conspire to drive the formation and variability of highly ionized accretion disc winds.
Artificial emotion and emotion learning: emotions as value judgements

The paper discusses the role of emotion in learning, presenting a connectionist learning architecture that indeed uses the concept of emotion in its learning rule. Presenting a working learning architecture based on the concept of emotion as value judgement, the paper contributes toward the efforts in answering the long-lasting question stated in psychology and philosophy: what is an emotion. The description of the architecture is followed by description of an experiment, in which the architecture is used as a learning controller in a process of training a simulated goalkeeper robot for a RoboCup match.
Expectation maximization and complex duration distributions for continuous time Bayesian networks

Continuous time Bayesian networks (CTBNs) describe structured stochastic processes with finitely many states that evolve over continuous time. A CTBN is a directed (possibly cyclic) dependency graph over a set of variables, each of which represents a finite state continuous time Markov process whose transition model is a function of its parents. We address the problem of learning the parameters and structure of a CTBN from partially observed data. We show how to apply expectation maximization (EM) and structural expectation maximization (SEM) to CTBNs. The availability of the EM algorithm allows us to extend the representation of CTBNs to allow a much richer class of transition durations distributions, known as phase distributions. This class is a highly expressive semi-parametric representation, which can approximate any duration distribution arbitrarily closely. This extension to the CTBN framework addresses one of the main limitations of both CTBNs and DBNs — the restriction to exponentially / geometrically distributed duration. We present experimental results on a real data set of people's life spans, showing that our algorithm learns reasonable models — structure and parameters — from partially observed data, and, with the use of phase distributions, achieves better performance than DBNs.
MR imaging of reversible cyclosporin A-induced neurotoxicity

Neurotoxicity is a recognized complication of cyclosporin A (CsA) therapy in patients undergoing organ transplantation. It is most commonly manifested by fever, seizures, and altered mental status. Cortical blindness and speech and motor disturbances can also occur. Changes seen in cerebral white matter on imaging studies are nonenhancing areas of hypoattenuation on CT and T2 prolongation on MR. We report three cases of CsA-induced neurotoxicity in which reversible changes were observed in the cerebral white matter. In the first patient, CsA neurotoxicity occurred 1 week following orthotopic liver transplantation. In the second patient, CsA neurotoxicity coincided with an episode of severe systemic hypertension 4 weeks after cardiac transplantation. The third patient experienced seizures 1 month after heart/lung transplantation for cystic fibrosis. A current theory postulates a relationship between diminished serum cholesterol and CsA neurotoxicity. This theory, however, does not satisfactorily address all cases of CsA neurotoxicity. In particular, serum cholesterol measurements were normal in cases 2 and 3 and probably were normal in case 1, despite diminished cholesterol levels preoperatively. Although the matter of CsA-induced neurotoxicity remains unresolved, we suggest that endothelin, a newly described neuropeptide that causes intense vasoconstriction and that has been implicated in cerebral vasospasm, may potentiate CsA-induced damage to endothelium and promote CsA neurotoxicity.
The RR Lyrae Distance Scale

We review seven methods of measuring the absolute magnitude Mv of RR Lyrae stars in light of the Hippareos mission and other recent developments. We focus on identifying possible systematic errors and rank the methods by relative immunity to such errors. For the three most robust methods, statistical parallax, trigonometric parallax, and cluster kinematics, we find My (at [Fe/H]= −1.6) of 0.77 ± 0.13, 0.71 ± 0.15, 0.67 ± 0.10. These methods cluster consistently around 0.71 ±0.07. We find that Baade-Wesselink and theoretical models both yield a broad range of possible values (0.45–0.70 and 0.45–0.65) due to systematic uncertainties in the temperature scale and input physics. Main-sequence fitting gives a much brighter Mv = 0.45 ± 0.04 but this may be due to a difference in the metallicity scales of the cluster giants and the calibrating subdwarfs. White-dwarf cooling-sequence fitting gives 0.67±0.13 and is potentially very robust, but at present is too new to be fully tested for systematics. If the three most robust methods are combined with Walker’s mean measurement for 6 LMC clusters, {tiV}0,LMC = 18.98±0.03 at [Fe/H]=−1.9, then μ LMC = 18.33±0.08.
Euclidean Embeddings and Riemannian Bergman Metrics

Consider the sum of the first N eigenspaces for the Laplacian on a Riemannian manifold. A basis for this space determines a map to Euclidean space and for N sufficiently large the map is an embedding. In analogy with a fruitful idea of Kahler geometry, we define (Riemannian) Bergman metrics of degree N to be those metrics induced by such embeddings. Our main result is to identify a natural sequence of Bergman metrics approximating any given Riemannian metric. In particular we have constructed finite dimensional symmetric space approximations to the space of all Riemannian metrics. Moreover the construction induces a Riemannian metric on that infinite dimensional manifold which we compute explicitly.