cssi/SciSciGPT-SciSciNet huggingface dataset:
Arousal and Locomotion Make Distinct Contributions to Cortical Activity Patterns and Visual Encoding

Spontaneous and sensory-evoked cortical activity is highly state-dependent, yet relatively little is known about transitions between distinct waking states. Patterns of activity in mouse V1 differ dramatically between quiescence and locomotion, but this difference could be explained by either motor feedback or a change in arousal levels. We recorded single cells and local field potentials from area V1 in mice head-fixed on a running wheel and monitored pupil diameter to assay arousal. Using naturally occurring and induced state transitions, we dissociated arousal and locomotion effects in V1. Arousal suppressed spontaneous firing and strongly altered the temporal patterning of population activity. Moreover, heightened arousal increased the signal-to-noise ratio of visual responses and reduced noise correlations. In contrast, increased firing in anticipation of and during movement was attributable to locomotion effects. Our findings suggest complementary roles of arousal and locomotion in promoting functional flexibility in cortical circuits.
A Model of Two-Dimensional Turbulence Using Random Matrix Theory

We derive a formula for the entropy of two-dimensional incompressible inviscid flow, by determining the volume of the space of vorticity distributions with fixed values for the moments Qk = ∫ ω(x)kd2x. This space is approximated by a sequence of spaces of finite volume, by using a regularization of the system that is geometrically natural and connected with the theory of random matrices. By taking the limit we get a simple formula for the entropy of a vortex field. We predict vorticity distributions of maximum entropy with given mean vorticity and enstrophy; we also predict the cylindrically symmetric vortex field with maximum entropy. This could be an approximate description of a hurricane.
Kinetic Resolution and Double Stereodifferentiation in Catalytic Asymmetric C−H Activation of 2-Substituted Pyrrolidines

Dirhodium tetrakis(S-(N-dodecylbenzenesulfonyl)prolinate) (Rh(2)(S-DOSP)(4)) catalyzed decomposition of methyl aryldiazoacetates in the presence of 2-substituted pyrrolidines results in highly diastereoselective and enantioselective C-H insertions. These reactions can proceed with impressive levels of double stereodifferentiation and kinetic resolution, which allows for three stereocenters to be controlled during the C-H insertion step.
Estimating volatility and dividend yield when valuing real options to invest or abandon

The opportunity to invest in or abandon a project can in principle be valued using real options techniques. In practice, option pricing has as inputs the volatility and dividend yield of the project, which are in most cases not observable via market data. Current methods of estimating these parameters are largely ad hoc, introducing potential error into the valuation process. This paper uses simple production models to formalize concepts for estimating project volatility and dividend yield, in single stochastic variable option models, and provides an example of how these estimates can be used in a real option valuation exercise.
Locally Adapted Tetrahedral Meshes Using Bisection

We present an algorithm for the construction of locally adapted conformal tetrahedral meshes. The algorithm is based on bisection of tetrahedra. A new data structure is introduced, which simplifies both the selection of the refinement edge of a tetrahedron and the recursive refinement to conformity of a mesh once some tetrahedra have been bisected. We prove that repeated application of the algorithm leads to only finitely many tetrahedral shapes up to similarity, and we bound the amount of additional refinement that is needed to achieve conformity. Numerical examples of the effectiveness of the algorithm are presented.
Dynamic Stiffness and Damping of Externally Pressurized Gas Lubricated Journal Bearings

A rigid vertical shaft was operated with known amounts of unbalance at speeds up to 30,000 rpm and gas supply pressure ratios to 4.8. From measured amplitude and phase angle data, dynamic stiffness and damping coefficients of the bearings were determined. The measured stiffness was proportional to the supply pressure, while damping was little affected by supply pressure. Damping dropped rapidly as the fractional frequency whirl threshold was approached. A small eccentricity analysis overpredicted the stiffness by 4 to 55 percent. Predicted damping was close to measured at low speeds but higher at high speeds.
Diastereocontrol in Asymmetric Allyl–Allyl Cross-Coupling: Stereocontrolled Reaction of Prochiral Allylboronates with Prochiral Allyl Chlorides

Palladium-catalyzed allyl–allyl cross-coupling was investigated with substituted prochiral allylic boronates. These reactions deliver products bearing adjacent stereocenters, and the issue of diastereocontrol is therefore paramount. Under appropriately modified conditions, this allyl–allyl coupling strategy was found to apply to a range of substrates, generally occurring with high enantioselectivity (92:8 to >99:1 er) and good diastereoselection (4:1 to 14:1 dr).
Status of cold dark matter cosmology

Abstract Cold Dark Matter (CDM) has become the standard modern theory of cosmological structure formation. Its predictions appear to be in good agreement with data on large scales, and it naturally accounts for many properties of galaxies. But despite its many successes, there has been concern about CDM on small scales because of the possible contradiction between the linearly rising rotation curves observed in some dark-matter-dominated galaxies vs. the 1/ r density cusps at the centers of simulated CDM halos. Other CDM issues on small scales include the very large number of small satellite halos in simulations, far more than the number of small galaxies observed locally, and problems concerning the angular momentum of the baryons in dark matter halos. The latest data and simulations have lessened, although not entirely resolved, these concerns. Meanwhile, the main alternatives to CDM that have been considered to solve these problems, self-interacting dark matter (SIDM) and warm dark matter (WDM), have been found to have serious drawbacks.
Partition functions in even dimensional AdS via quasinormal mode methods

In this note, we calculate the one-loop determinant for a massive scalar (with conformal dimension Δ) in even-dimensional AdS d+1 space, using the quasinormal mode method developed in [1] by Denef, Hartnoll, and Sachdev. Working first in two dimensions on the related Euclidean hyperbolic plane H 2, we find a series of zero modes for negative real values of Δ whose presence indicates a series of poles in the one-loop partition function Z(Δ) in the Δ complex plane; these poles contribute temperature-independent terms to the thermal AdS partition function computed in [1]. Our results match those in a series of papers by Camporesi and Higuchi, as well as Gopakumar et al. [2] and Banerjee et al. [3]. We additionally examine the meaning of these zero modes, finding that they Wick-rotate to quasinormal modes of the AdS2 black hole. They are also interpretable as matrix elements of the discrete series representations of SO(2, 1) in the space of smooth functions on S 1. We generalize our results to general even dimensional AdS2n , again finding a series of zero modes which are related to discrete series representations of SO(2n, 1), the motion group of H 2n .
Roll Damping for Projectiles Including Wraparound, Offset, and Arbitrary Number of Fins

An algebraic correlation for the roll-damping and roll-producing moments for finned projectiles and missiles has been extended and verified to accept bodies with an arbitrary number of fins—not only cruciform fins, but curved wraparound fins with fin cant, and fins with offset angles. The extended correlation is applicable at subsonic, transonic, and supersonic speeds. A direct method to compute the fin roll-producing moment from the fin normal force is provided to circumvent the existing lengthy and cumbersome semiempirical methods. Seven different missile and projectile configurations with widely varying fin shapes and sizes were tested, and their measured data are tabulated. The present correlation is very simple, and can be used to refine initial configuration selection and thus reduce the number of costly full-flowfield computations. The correlation is limited to missiles with only one set of fins and to small angles of attack.
Efficient approximation algorithms for domatic partition and on-line coloring of circular arc graphs

Abstract We exploit the close relationship between circular arc graphs and interval graphs to design efficient approximation algorithms for NP-hard optimization problems on circular arc graphs. The problems considered here are maximum domatic partition and on-line minimum vertex coloring. We present a heuristic for the domatic partition problem with a performance ratio of 4. For on-line coloring, we consider two different on-line models. In the first model, arcs are presented in the increasing order of their left endpoints. For this model, our heuristic guarantees a solution which is within a factor of 2 of the optimal (off-line) value; and we show that no on-line coloring algorithm can achieve a performance guarantee of less than 4 3 . In the second on-line model, arcs are presented in an arbitrary order; and it is known that no on-line coloring algorithm can achieve a performance guarantee of less than 3. For this model, we present a heuristic which provides a performance guarantee of 4.
On minimal representations of Petri net languages

Given a measure of size of a labeled Petri net, we consider the existence of a procedure that takes as input a description of an arbitrary, labeled Petri net, and returns a description of a (possibly different) labeled Petri net with the smallest size that generates the same language as the input. We refer to such procedures as minimization procedures. In this note, we investigate the existence of minimization procedures for a variety of measures. We show that these procedures cannot exist for Petri net languages for a large class of measures. However, for families of Petri net languages where controllability (cf. ), and consequently language-containment, is decidable , there can be minimization procedures for a restricted class of measures. After showing that minimization procedures for a family of measures are intractable for languages generated by bounded Petri nets, it is argued that a similar conclusion has to be reached for any family of Petri net languages that includes the family of regular languages for which there are minimization procedures.
Decomposing Residential Self-Selection via a Life-Course Perspective

We propose a decomposition of residential self-selection by understanding the process of its formation. We take a life-course perspective and postulate that locations experienced early in life can have a lasting effect on our locational preferences later in life. In other words, what was experienced spatially is a key factor contributing to our residential self-selection, and our preferences in residential locations are formed long before the onset of our self-selection. We further hypothesize that this prior-location influence is modified by the duration and recency of the prior stay. Using a dataset collected in the New York City Area, we estimated a series of multinomial logit models to test these hypotheses. The results confirm the prior-location influence and demonstrate that this precedes residential self-selection and is impacted by its own properties such as duration and recency. Furthermore, the analysis separating child-bearing households from non-child-bearing households shows an interaction be...
Latin American Law: A History of Private Law and Institutions in Spanish America

This book offers the first comprehensive introduction in either English or Spanish to private law in Spanish Latin America from the colonial period to the present. After a brief discussion of pre-Spanish indigenous law, M. C. Mirow organizes the book into three substantial sections that describe private law and legal institutions in the colonial period, the independence era and nineteenth century, and the twentieth century. Each section begins with an introduction to the nature and function of private law during the period and discusses such topics as legal education and lawyers, legal sources, courts, land, inheritance, commercial law, family law, and personal status. Each section also presents themes of special interest during its respective time period, including slavery, Indian status, codification, land reform, and development and globalization. As the first substantive treatment of Latin American law from colonial times to the present, this book establishes a way to define and structure the field. It also underscores the importance of private law and legal institutions in the creation and control of colonies and nations and provides a basis for understanding the place of law in modern political change.
Distinguishing first-line defaults and second-line conceptualization in reasoning about humans, robots, and computers

In the previous research, we demonstrated that people distinguish between human and nonhuman intelligence by assuming that humans are more likely to engage in intentional goal-directed behaviors than computers or robots. In the present study, we tested whether participants who respond relatively quickly when making predictions about an entity are more or less likely to distinguish between human and nonhuman agents on the dimension of intentionality. Participants responded to a series of five scenarios in which they chose between intentional and nonintentional actions for a human, a computer, and a robot. Results indicated that participants who chose quickly were more likely to distinguish human and nonhuman agents than participants who deliberated more over their responses. We suggest that the short-response time participants were employing a first-line default to distinguish between human intentionality and more mechanical nonhuman behavior, and that the slower, more deliberative participants engaged in deeper second-line reasoning that led them to change their predictions for the behavior of a human agent.
Subsolidus Phase Diagram of the Bi2O3‐Gd2O3 System and the Morphology of Phase Separation

The low-temperature, subsolidus phase diagram for the binary system Bi2O3-Gd2O3 was determined using X-ray diffraction (XRD), electron microprobe analysis (EPMA), and conductivity measurements. The high-temperature phase in Bi2O3-rich compositions is cubic (CaF2 structure). A simple eutectoid reaction from cubic → monoclinic + rhombohedral phases was observed, leading to the formation of a cellular structure. The eutectoid temperature and composition are ∼683°C and 8.8% Gd2O3, respectively. The cubic phase containing ∼27.5% Gd2O3 congruently transforms into the rhombohedral phase at ∼810°C. The solubility of Gd2O3 in the monoclinic phase was determined to be negligible. The concentration of Gd2O3 in the rhombohedral phase in equilibrium with the monoclinic phase is ∼18% Gd2O3. Samples with Gd2O3 concentration greaterthan equal to10% undergo a composition-invariant, thermally activated (massive) transformation to a metastable rhombohedral phase below a composition-dependent critical temperature, Tc(2), followed by its decomposition into a rhombohedral (of equilibrium composition) + monoclinic two-phase mixture upon further annealing. The resulting monoclinic phase appears to form by nucleation and growth. Samples containing ≤7% Gd2O3 undergo cubic → tetragonal displacive transformation upon cooling below another composition-dependent critical temperature, Tc(1). A long-term annealing leads to decomposition of the tetragonal phase into a mixture of rhombohedral and monoclinic phases. The resulting microstructure was extremely fine and typical of a cellular reaction.
Inside "Pandora's box": abused women's experiences with clinicians and health services.

OBJECTIVE: To explore the attitudes and experiences of abused women to identify characteristics that helped or hindered abuse disclosure to clinicians and to determine how women viewed potential interventions to improve detection and treatment in a medical setting.
Effects of compressibility on the instability of liquid sheets

The effect of compressibility of fluids on the instability of a liquid sheet issued from a nozzle into an ambient gas is investigated by use of linear stability analysis. It is found that increasing the gas Mach number from subsonic to transonic causes the maximum growth rate, dominant wave number, and cut-off wave number of disturbances to increase. Liquid compressibility has a minimal effect on instability. At a constant wave number, the growth rate of disturbances increases as the gas Mach number tends to 1 and then begins to decline with further increase in the gas Mach number. Hence, liquid sheet breakup is due to surface disintegration not gross fracturing in agreement with experimental observations. At small values of wave number, antisymmetrical disturbances grow faster than symmetrical ones while the growth rate of both types of disturbances approach each other at large wave numbers. At small Weber number, antisymmetrical disturbances exhibit a higher maximum growth rate and a lower dominant wave...
345-GHz array receiver for the Heinrich Hertz Telescope

In this paper, we present the design and construction of DesertSTAR, a seven pixel heterodyne receiver for the 345 GHz atmospheric window for operation on the Heinrich Hertz Telescope located at Mt.Graham, Arizona. The seven beams are arranged in a hexagonal close-packed pattern with one beam spacing. The instrument uses fixed tuned split-block, half- height waveguide mixers with Nb SIS junctions. The mixers have an instantaneous bandwidth of 2 GHz, centered on 5 GHz. The cryostat uses a NRAO Joule-Thompson refrigerator to cool the mixers, isolators, amplifiers and optics to 4K. The computer controlled bias system allows automated bias optimization and monitoring both locally and remotely. The instrument will take full advantage of the good 345 GHz weather at the HHT and dramatically increase scientific throughput. We expect to have first operations with seven pixels in November, 2000.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Toward earthquake early warning in northern California

[1] Earthquake early warning systems are an approach to earthquake hazard mitigation which takes advantage of the rapid availability of earthquake information to quantify the hazard associated with an earthquake and issue a prediction of impending ground motion prior to its arrival in populated or otherwise sensitive areas. One such method, Earthquake Alarm Systems (ElarmS) has been under development in southern California and, more recently, in northern California. Event magnitude is estimated using the peak amplitude and the maximum predominant period of the initial P wave. ElarmS incorporates ground motion prediction equations and algorithms from ShakeMap for prediction of ground motions in advance of the S wave arrival. The first peak ground motion estimates are available 1 s after the first P wave trigger, and are updated each second thereafter for the duration of the event. The ElarmS methodology has been calibrated using 43 events ranging in size from ML 3.0 to Mw 7.1 that occurred in northern California since 2001. We present the results of this calibration, as well as the first implementation of ElarmS in an automated, noninteractive setting and the results of 8 months of noninteractive operation in northern California. Between February and September 2006, ElarmS successfully processed 75 events between Md 2.86 to Mw 5.0. We find that the ElarmS methodology processed these events reliably and accurately in the noninteractive setting. The median warning time afforded by this method is 49 s at the major population centers of the Bay Area. For these events the magnitude estimate is within an average of 0.5 units of the network-derived magnitude, and the ground motion prediction from ElarmS is within an average of 0.1 units of the observed modified Mercalli intensity.
Initial electron distributions for free-electron lasers generated by injector and accelerator simulations

Abstract Early free electron laser (FEL) development was guided by simple performance criteria based on the number of undulator periods, electron beam quality, and current. The beam quality (emittance and energy spread) was used to characterize the initial distribution of axial electron velocities along the undulator axis. While the emittance and energy spread determine the overall width of the distribution, its detailed shape is also important. As new accelerators are designed specifically for FEL applications, it becomes important to obtain distribution shape information from simulations that include the electron gun, accelerator, and beam transport in addition to the usual electron/optical interaction in the undulator. The distribution at the entrance to the undulator can be calculated from numerical simulations of the cathode emission, acceleration, and transport of an electron beam. We have modeled the beam generation, from cathode emission up to the energy of the accelerator injector, using an axisymmetric, cylindrical geometry particle simulation (DPC). This code solves the relativistic force equation with fields obtained from Maxwell's equations in the Darwin model. The DPC calculation is run repeatedly varying parameters such as accelerating stress, electrode configuration, and axial magnetic field profile until a good match is obtained for the accelerator. The beam exiting from the injector can be accelerated and transported using the transfer matrix technique with a simple model for accelerating gaps and magnets. Alternatively, acceleration and transport can be simulated with a particle code that solves for the axisymmetric evolution of a slice of an electron beam including possible emittance growth. The phase space obtained from the accelerator can be evaluated for performance using either the simple FEL integral equation method or the more complete FRED simulation code.
Linear quadratic regulator with varying finite time durations

The optimal state trajectories of time-invariant linear quadratic regulator problems with different time horizons can be found from a single Riccati gain matrix shifted appropriately in time. This result has significant ramifications for real-time implementation of optimal controllers driving systems at various speeds
Overview of Containerless Processing Technologies

In the near future, a large segment of the scientific community will have an opportunity to perform materials processing experiments on the Space Shuttle in the reduced gravity environment of space. Many of these experiments will require containerless processing techniques that provide manipulation and control of weightless (molten) materials without physical contact with container walls or other holding devices. A variety of containerless processing technologies are now being developed for space and ground-based materials processing facilities. The utilization of air jets or high intensity acoustic, electromagnetic or electrostatic fields can produce forces that support and manipulate materials. Most of the present containerless research is directed toward the development of high temperature systems capable of melting and resolidifying materials. This paper will review the materials processing capabilities and level of developmental progress of each technique. An introduction to available NASA test facilities will also be given.
Approximation algorithms for the bid construction problem in combinatorial auctions for the procurement of freight transportation contracts

Trucking companies (carriers) are increasingly facing combinatorial auctions conducted by shippers seeking contracts for their transportation needs. The bid valuation and construction problem for carriers facing these combinatorial auctions is very difficult and involves the computation of a number of NP-hard sub problems. In this paper we examine computationally tractable approximation methods for estimating these values and constructing bids. The benefit of our approximation method is that it provides a way for carriers to discover their true costs and construct optimal or near optimal bids by solving a single NP-hard problem. This represents a significant improvement in computational efficiency. We examine our method both analytically and empirically using a simulation based analysis.
Long-term barriers to economic development

What obstacles prevent the most productive technologies from spreading to less developed economies from the world’s technological frontier? In this paper, we seek to shed light on this question by quantifying the geographic and human barriers to the transmission of technologies. We argue that the intergenerational transmission of human traits, particularly culturally transmitted traits, has led to divergence between populations over the course of history. In turn, this divergence has introduced barriers to the diffusion of technologies across societies. We provide measures of historical and genealogical distances between populations, and document how such distances, relative to the world’s technological frontier, act as barriers to the diffusion of development and of specific innovations. We provide an interpretation of these results in the context of an emerging literature seeking to understand variation in economic development as the result of factors rooted deep in history.
THE TRAVELING SALESMAN PROBLEM FOR LINES AND RAYS IN THE PLANE

In the Euclidean TSP with neighborhoods (TSPN), we are given a collection of n regions (neighborhoods) and we seek a shortest tour that visits each region. In the path variant, we seek a shortest path that visits each region. We present several linear-time approximation algorithms with improved ratios for these problems for two cases of neighborhoods that are (infinite) lines, and respectively, (half-infinite) rays. Along the way we derive a tight bound on the minimum perimeter of a rectangle enclosing an open curve of length L.
Price changes, maintenance, and the rate of depreciation

This study estimates rates of deterioration and depreciation for a sample of used privately owned single- and twin-engine aircraft over the period 1971–1991. The adoption of a strict liability stan...
Solid state NMR characterization and flammability of styrene–acrylonitrile copolymer montmorillonite nanocomposite

Abstract This work investigates the melt-processing of styrene–acrylonitrile copolymer (SAN) with organo-modified montmorillonite (MMT) clays and the influence of the clay on mechanical properties and on fire performance of SAN. The nanodispersion of MMT is evaluated qualitatively by X-ray diffraction (XRD) and transmission electronic microscopy (TEM), and quantitatively by solid state nuclear magnetic resonance (NMR). SAN/MMT nanocomposites reveal an intermediate morphology, an intercalated structure with some exfoliation and with the presence of small tactoids, whatever the loading in MMT is. The polymer–clay interfacial area is estimated at 0.5 and the degree of homogeneity characterizing the distribution of MMT platelets is about 40%. The presence of clay in SAN-25 leads to a ‘filler effect’ increasing the stiffness but decreasing tensile strength of the nanocomposites. It also leads to a significant decrease of peak of heat release rate measured by mass loss calorimetry.
An Integrated Method for Planning and Scheduling to Minimize Tardiness

We combine mixed integer linear programming (MILP) and constraint programming (CP) to minimize tardiness in planning and scheduling. Tasks are allocated to facilities using MILP and scheduled using CP, and the two are linked via logic-based Benders decomposition. We consider two objectives: minimizing the number of late tasks, and minimizing total tardiness. Our main theoretical contribution is a relaxation of the cumulative scheduling subproblem, which is critical to performance. We obtain substantial computational speedups relative to the state of the art in both MILP and CP. We also obtain much better solutions for problems that cannot be solved to optimality.
Data center demand response: avoiding the coincident peak via workload shifting and local generation

Demand response is a crucial aspect of the future smart grid. It has the potential to provide significant peak demand reduction and to ease the incorporation of renewable energy into the grid. Data centers' participation in demand response is becoming increasingly important given the high and increasing energy consumption and the flexibility in demand management in data centers compared to conventional industrial facilities. In this extended abstract we briefly describe recent work in our full paper on two demand response schemes to reduce a data center's peak loads and energy expenditure: workload shifting and the use of local power generations. In our full paper, we conduct a detailed characterization study of coincident peak data over two decades from Fort Collins Utilities, Colorado and then develop two algorithms for data centers by combining workload scheduling and local power generation to avoid the coincident peak and reduce the energy expenditure. The first algorithm optimizes the expected cost and the second one provides a good worst-case guarantee for any coincident peak pattern. We evaluate these algorithms via numerical simulations based on real world traces from production systems. The results show that using workload shifting in combination with local generation can provide significant cost savings (up to 40% in the Fort Collins Utilities' case) compared to either alone.
Learning nested agent models in an information economy

Abstract. We present our approach to the problem of how an agent, within an economic multi-agent system, can determine when it should behave strategically (i.e. learn and use models of other agents), and when it should act as a simple price-taker. We provide a framework for the incremental implementation of modelling capabilities in agents, and a description of the forms of knowledge required. The agents were implemented and different populations simulated in order to learn more about their behaviour and the merits of using and learning agent models. Our results show, among other lessons, how savvy buyers can avoid being ‘cheated’ by sellers, how price volatility can be used to quantitatively predict the benefits of deeper models, and how specific types of agent populations influence system behaviour.
Influencing Customers through Customers: Simulation of Herd Behavior in Supermarkets

This work proposes a supermarket optimization simulation model called Swarm-Moves is based on self organized complex system studies to identify parameters and their values that can influence customers to buy more on impulse in a given period of time. In the proposed model, customers are assumed to have trolleys equipped with technology like RFID that can aid the passing of products' information directly from the store to them in real-time and vice-versa. Therefore, they can get the information about other customers purchase patterns and constantly informing the store of their own shopping behavior. This can be easily achieved because the trolleys “know” what products they contain at any point. The Swarm-Moves simulation is the virtual supermarket providing the visual display to run and test the proposed model. The simulation is also flexible to incorporate any given model of customers' behavior tailored to particular supermarket, settings, events or promotions. The results, although preliminary, are promising to use RFID technology for marketing products in supermarkets and provide several dimensions to look for influencing customers via feedback, real-time marketing, target advertisement and on-demand promotions.
A performance model of non-deterministic particle transport on large-scale systems

In this work we present a predictive analytical model that encompasses the performance and scaling characteristics of a nondeterministic particle transport application, MCNP (Monte Carlo N-Particle), that represents part of the Advanced Simulation and Computing (ASC) workload. MCNP can be used for the simulation of neutron, photon, electron, or coupled transport, and has found uses in many problem areas including nuclear reactors, radiation shielding, and medical physics. Monte Carlo methods in general and MCNP specifically do not solve an explicit equation, but rather obtain answers by simulating the interactions between individual particles and a predefined geometry. This is in contrast to deterministic transport methods, the most common of which is the discrete ordinates method, that solve the transport equation directly for the average particle behavior.Previous studies on the scalability of parallel Monte Carlo calculations have been rather general in nature. The performance model developed here is both detailed and parametric with both application characteristics (e.g. problem size), and system characteristics (e.g. communication latency, bandwidth, achieved processing rate) serving as input. The model is validated against measurements on an AlphaServer ES40 system showing high accuracy across many processor/problem combinations. The model is then used to provide insight into the achievable performance that should be possible on systems containing thousands of processors and to quantify the impact that possible improvements in sub-system performance may have. In addition, the impact on performance of modifying the communication structure of the code is also quantified.
Connecting the very large and the very small : effective particle mass in curved-space cosmological models

We investigate the propagation of electromagnetic fields and potentials in the plasma of the early Universe, assuming a Friedmann-Robertson-Walker background with negative curvature. Taking over results from classical plasma physics, we show that charged particles will acquire an effective mass that has not only the expected thermal component but also a non-thermal component due to the influence of distant matter. Although this is a direct effect of the vector potential, we show the theory is nevertheless gauge invariant. This phenomenon is therefore in the same category as the Aharonov-Bohm effect. The non-thermal component becomes increasingly important with time, and in some cosmological models can prove to be of decisive importance in bringing about the phase transition that generates normal masses.
You Owe It to Yourself: Boosting Retirement Saving with a Responsibility-Based Appeal.

Americans are not saving enough for retirement. Previous research suggests that this is due, in part, to people's tendency to think of the future self as more like another person than like the present self, making saving feel like giving money away rather than like investing in oneself. Using objective employer saving data, a field experiment capitalized on this phenomenon to increase saving. It compared the effectiveness of a novel message--one appealing to people's sense of "social" responsibility to their future selves--with a more traditional appeal to people's sense of rational self-interest. The social-responsibility-to-the-future-self message resulted in larger increases in saving than the self-interest message, but only to the extent that people felt a strong "social" connection to their future selves. These results broaden our understanding of the psychology of moral responsibility and refine our understanding of the role of future-self continuity in fostering intertemporal patience. They further demonstrate how understanding conceptions of the self over time can suggest solutions to important and challenging policy problems.
A heavy-tailed distribution for ARCH residuals with application to volatility prediction

The quest for the ‘best’ heavy-tailed distribution for ARCH/GARCH residuals appears to still be ongoing. In this connection, we propose a new distribution that arises in a natural way as an outcome of an implicit model. The challenging application of prediction of squared returns is also discussed; an optimal predictor is formulated, and the usefulness of the new distribution for prediction is demonstrated on three real datasets. c ∞ 2004 Peking University Press
Distributions of H2O and CO2 ices on Ariel, Umbriel, Titania, and Oberon from IRTF/SpeX observations

We present 0.8–2.4 μm spectral observations of uranian satellites, obtained at IRTF/SpeX on 17 nights during 2001–2005. The spectra reveal for the first time the presence of CO2 ice on the surfaces of Umbriel and Titania, by means of 3 narrow absorption bands near 2 μm. Several additional, weaker CO2 ice absorptions have also been detected. No CO2 absorption is seen in Oberon spectra, and the strengths of the CO2 ice bands decline with planetocentric distance from Ariel through Titania. We use the CO2 absorptions to map the longitudinal distribution of CO2 ice on Ariel, Umbriel, and Titania, showing that it is most abundant on their trailing hemispheres. We also examine H2O ice absorptions in the spectra, finding deeper H2O bands on the leading hemispheres of Ariel, Umbriel, and Titania, but the opposite pattern on Oberon. Potential mechanisms to produce the observed longitudinal and planetocentric distributions of the two ices are considered.
Milkshake Prices, International Reserves, and the Mexican Peso

Menu prices from 13 international restaurant franchises that operate in both El Paso and Ciudad Juarez are utilized to examine the behavior over time of the peso/dollar exchange rate. Parametric and non-parametric tests indicate that the price ratio alone provides a biased estimator of the exchange rate. In addition to the multi-product price ratio, the empirical analysis also incorporates interst rate prity and balance of payment variables. The combination of unique microeconomic sample data with national macroeconomic variables illustrates one manner in which border economies provide information regarding the interplay of financial markets between Mexico and the United States.
IC-integrated flexible shear-stress sensor skin

This paper reports the successful development of the first IC-integrated flexible MEMS shear-stress sensor skin. The sensor skin is 1 cm wide, 2 cm long, and 70 /spl mu/m thick. It contains 16 shear-stress sensors, which are arranged in a 1-D array, with on-skin sensor bias, signal-conditioning, and multiplexing circuitry. We further demonstrated the application of the sensor skin by packaging it on a semicylindrical aluminum block and testing it in a subsonic wind tunnel. In our experiment, the sensor skin has successfully identified both the leading-edge flow separation and stagnation points with the on-skin circuitry. The integration of IC with MEMS sensor skin has significantly simplified implementation procedures and improved system reliability.
Mixture-of-parents maximum entropy Markov models

We present the mixture-of-parents maximum entropy Markov model (MoP-MEMM), a class of directed graphical models extending MEMMs. The MoP-MEMM allows tractable incorporation of long-range dependencies between nodes by restricting the conditional distribution of each node to be a mixture of distributions given the parents. We show how to efficiently compute the exact marginal posterior node distributions, regardless of the range of the dependencies. This enables us to model non-sequential correlations present within text documents, as well as between interconnected documents, such as hyperlinked web pages. We apply the MoP-MEMM to a named entity recognition task and a web page classification task. In each, our model shows significant improvement over the basic MEMM, and is competitive with other long-range sequence models that use approximate inference.
Conceptual Structure of Performance Assessments Conducted for the Waste Isolation Pilot Plant

The Waste Isolation Pilot Plant: (WIPP) in southeastern New Mexico is being developed by the US Department of Energy as a disposal facility for transuranic waste. In support of this project, Sandia National Laboratories is conducting an ongoing performance assessment (PA) for the WIPP. The ordered triple- representation for risk proposed by Kaplan and Garrick is used to provide a clear conceptual structure for this PA. This presentation describes how the preceding representation provides a basis in the WIPP PA for (1) the definition of scenarios and the calculation of scenario probabilities and consequences, (2) the separation of subjective and stochastic uncertainties, (3) the construction of the complementary cumulative distribution functions required in comparisons with the US Environmental Protection Agency`s standard for the geologic disposal of radioactive waste (i.e., 40 CFR Part 191, Subpart B), and (4) the performance of uncertainty and sensitivity studies. Results obtained in a preliminary PA for the WIPP completed in December of 1991 are used for illustration.
High Resolution Scanning Microscopy of Biological Specimens

A scanning microscope is described which is capable of a point resolution of 0.5 nm. We have demonstrated that it can produce the same kinds of micrographs as a conventional microscope. However, by using several detectors to produce signals corresponding to different groups of transmitted electrons we are able to produce an image contrast closely proportional to Z, the atomic number. Such a system is very promising for the study of stained molecules.
Taming lambda's for applications; the OptIPuter system software

We are developing application abstractions called distributed virtual computers (DVC), which simplify application use of dynamic optical resources. DVC descriptions naturally express communication and computation resource requirements, enabling coordinated resource binding. We describe initial experience with DVCs and how they provide an integrating architecture for lambda grids. The OptIPuter project is a large multiinstitutional project led by Larry Smarr at the University of California, San Diego (UCSD) and Tom DeFanti at the University of Illinois at Chicago (UIC). Other software efforts include optical signaling software, visualization, distributed configuration management, and two driving applications involving petabytes of data. We are also constructing a high-speed OptIPuter testbed.
On a species survival model

In this paper we provide some sharp asymptotic results for a stochastic model of species survival recently proposed by Guiol, Machado, and Schinazi.
Management of Acquired Bleeding Problems in Cancer Patients

Cancer patients can have acquired bleeding problems for many reasons. In this review, an approach to the evaluation and management of the bleeding patient is discussed. Specific issues including coagulation defects, thrombocytopenia, platelet dysfunction, and bleeding complications of specific hematological malignancies due to anticoagulation, are discussed.
The ecologically noble savage debate

Debate around the ecologically noble savage represents two markedly different research threads. The first addresses the issue of conservation among native peoples and narrowly focuses on case studies of resource use of ethnographic, archaeological, or historic sources. The second thread is broader and more humanistic and political in orientation and considers the concept of ecological nobility in terms of identity, ecological knowledge, ideology, and the deployment of ecological nobility as a political tool by native peoples and conservation groups.
Detecting residual tumor after excisional biopsy of impalpable breast carcinoma: efficacy of comparing preoperative mammograms with radiographs of the biopsy specimen

The purpose of this study was to ascertain whether a comparison of preoperative mammograms with radiographs of biopsy specimens is useful for determining the presence of residual breast tumor after an initial excision of impalpable breast cancer.Radiographs of tissue specimens obtained at the initial biopsy of 125 impalpable breast cancers were compared with the preoperative mammograms to determine if the lesion seen on the mammogram was completely excised. All tumors were impalpable, necessitating preoperative wire localization. The biopsies were usually excisional, and no special efforts were made to remove additional surrounding tissue. Specimen radiographs were rated as showing no residual tumor if the lesion appeared to be completely excised, showing residual tumor if the lesion did not appear to be completely removed, or indeterminate for residual tumor if adequacy of excision was uncertain. The presence or absence of tumor at the margins of the surgical specimen was determined by histologic examina...
Non-supersymmetric black holes and topological strings

We study non-supersymmetric, extremal four-dimensional black holes which arise upon compactification of type II superstrings on Calabi–Yau (CY) threefolds. We propose a generalization of the Ooguri–Strominger–Vafa (OSV) conjecture for higher-derivative corrections to the non-supersymmetric black hole entropy, in terms of the one-parameter refinement of topological string introduced by Nekrasov. We also study the attractor mechanism for non-supersymmetric black holes and show how the inverse problem of fixing charges in terms of the attractor value of CY moduli can be explicitly solved.
Effects of corneal thickness, corneal curvature, and intraocular pressure level on Goldmann applanation tonometry and dynamic contour tonometry.

Purpose To compare the measurements of intraocular pressure (IOP) with Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) and the effects of central corneal thickness (CCT), corneal curvature, and level of IOP on these methods. Design Cross-sectional population-based study. Participants From the Los Angeles Latino Eye Study, 2157 participants of primarily Mexican ancestry. Methods Average GAT measurements were compared to DCT, and both were examined with respect to CCT (≤500, 501–550, 551–600, >600 microns), corneal curvature ( 46 diopters), and level of IOP (0–10, 11–20, >20 mmHg). Main Outcome Measures Mean GAT and DCT IOP levels were compared for the entire population, and then trends for the CCT, curvature, and IOP groupings were analyzed. The magnitude of the difference of GAT minus DCT was compared for these different strata, with special attention to a difference of ± 3 mmHg or greater, which was defined as clinically significant. Results Mean IOP for the entire population by GAT was significantly lower (14.4±3.2 mmHg) compared with DCT (16.0±3.6; P P P = 0.0012, respectively). The difference between GAT and DCT was largest for thin CCT and decreased for thicker CCT ( P P = 0.02) but not GAT ( P = 0.3) such that mean DCT IOP increased with increasing corneal curvature. After adjusting for the CCT effect on IOP and stratifying by DCT IOP groups, the greatest difference between GAT and DCT was seen in the lowest IOP group (3.55±3.1), became negative in the intermediate group (−1.86±2.60), and was most negative in the highest IOP group (−3.88±3.3; P Conclusions Intraocular pressure measured by GAT was consistently lower when compared with DCT, and this difference was greatest with thinner CCT. Dynamic contour tonometry was also less affected by variations in CCT. Corneal curvature affected IOP measurements with DCT but not GAT, but this effect was less than the CCT effect on GAT. Goldmann applanation tonometry tended to underestimate IOP at higher levels and overestimate it at lower IOP levels when compared to DCT.
Thermal and rhodium acetate catalyzed reactions of 5-diazouracil with nucleophiles

Abstract In the presence of rhodium acetate 5-diazouracil reacts with varied secondary amines, azoles and thiols to give 5-substituted-uracils efficiently.