cssi/SciSciGPT-SciSciNet huggingface dataset:
Evolutionary games on the lattice: best-response dynamics

The best-response dynamics is an example of an evolutionary game where players update their strategy in order to maximize their payoff. The main objective of this paper is to study a stochastic spatial version of this game based on the framework of interacting particle systems in which players are located on an infinite square lattice. In the presence of two strategies, and calling a strategy selfish or altruistic depending on a certain ordering of the coefficients of the underlying payoff matrix, a simple analysis of the nonspatial mean-field approximation of the spatial model shows that a strategy is evolutionary stable if and only if it is selfish, making the system bistable when both strategies are selfish. The spatial and nonspatial models agree when at least one strategy is altruistic. In contrast, we prove that in the presence of two selfish strategies and in any spatial dimension, only the most selfish strategy remains evolutionary stable. The main ingredients of the proof are monotonicity results and a coupling between the best-response dynamics properly rescaled in space with bootstrap percolation to compare the infinite time limits of both systems.
PEPPI: a peptidomic database of human protein isoforms for proteomics experiments.

Background Protein isoform generation, which may derive from alternative splicing, genetic polymorphism, and posttranslational modification, is an essential source of achieving molecular diversity by eukaryotic cells. Previous studies have shown that protein isoforms play critical roles in disease diagnosis, risk assessment, sub-typing, prognosis, and treatment outcome predictions. Understanding the types, presence, and abundance of different protein isoforms in different cellular and physiological conditions is a major task in functional proteomics, and may pave ways to molecular biomarker discovery of human diseases. In tandem mass spectrometry (MS/MS) based proteomics analysis, peptide peaks with exact matches to protein sequence records in the proteomics database may be identified with mass spectrometry (MS) search software. However, due to limited annotation and poor coverage of protein isoforms in proteomics databases, high throughput protein isoform identifications, particularly those arising from alternative splicing and genetic polymorphism, have not been possible.
QSym over Sym has a stable basis

We prove that the subset of quasisymmetric polynomials conjectured by Bergeron and Reutenauer to be a basis for the coinvariant space of quasisymmetric polynomials is indeed a basis. This provides the first constructive proof of the Garsia-Wallach result stating that quasisymmetric polynomials form a free module over symmetric polynomials and that the dimension of this module is n!.
TOWARDS A SCHUBERT CALCULUS FOR MAPS FROM A RIEMANN SURFACE TO A GRASSMANNIAN

The intuitive notion of the Gromov invariant for maps from a Riemann surface to a Grassmannian is shown to agree with the definition in \cite{BDW}. Also, an induction on the genus is proved, which extends the results of \cite{BDW} to a computation of all Gromov invariants associated to G(2,k). This is shown to agree with the conjectured formula of Vafa and Intriligator.
Minimal realization of discrete linear systems from input-output observations

A direct procedure is presented for obtaining a minimal realization of a multiple-input multiple-output linear time-invariant discrete system from observations of the input and output. Discussion is limited to the case of noise-free observations in order to focus attention on the realization procedure and to display the structure of the resulting realization. This known structural form car be used as a check on the realization procedure. Application of the procedure requires knowledge of an upper bound on the minimal system dimension; however, a modification is given to handle the situation where an upper bound is not known. An example is included to show the operation of the procedure.
A variational principle for the equations of viscopiezoelectricity

The three-dimensional equations of linear viscopiezoelectricity and an accompanying electromechanical energy theorem are deduced, by the quasielectrostatic approximation, from the equations of viscoelectromagnetism and a generalized Poynting's theorem, respectively. For a viscopiezoelectric solid of volume V and bounding surface S, the internal energy, kinetic energy, and electric enthalpy densities as well as the variation of work done over S and the variation of energy dissipation in V are defined. A variational principle in terms of the defined functions is presented. It is shown that, from the principle, the equations of viscopiezoelectricity in V and the natural boundary conditions on S are obtained.
Combining insurance, contingent debt, and self-retention in an optimal corporate risk financing strategy

The authors provide a conceptual framework for designing a comprehensive risk financing strategy for a firm, using an optimal combination of three instruments: self-retention, contingent debt, and insurance. Using an original conceptual model, the risk management decisions of the firm are first decomposed into two sets-choosing attachment points for each layer of financing used in the overall risk financing structure, and, then determining optimal risk allocation arrangements within each layer of risk. This model allows the authors to show how these optimal risk financing arrangements are driven by the costs of risk management instruments, the risk characteristics, and the firm's borrowing constraints. Finally, the authors provide an original perspective to think about optimal ex ante risk management strategies, based on a combination of insurance, savings, and credit at the microeconomic or macroeconomic levels.
Impact of unbalance on electrical and torsional resonances in power electronic interfaced wind energy systems

Type 3 wind generators in series compensated networks could lead to subsynchronous resonances (SSR). Previous research focuses on balanced operation only. In this paper, impact of unbalance on Type 3 wind energy systems is investigated in two aspects: (i) impact on electric resonances and (ii) impact on torsional resonances. In the first aspect, impedance models of the system in DQ domain and phase domain are developed. Particularly, negative sequence impedances are examined. Nyquist stability criterion is applied to detect possible resonances. In the second aspect, transfer functions of the electromagnetic torque versus the rotating speed due to negative sequence components are developed. The impact of negative sequence components on electromechanical damping is then analyzed. The analysis results are verified by time-domain simulation results.
Control of carbenoid reactivity through neighboring group participation

Abstract Product distribution in the rhodium(II) carboxylate catalyzed decomposition of vinyldiazomethanes in the presence of N-(BOC)pyrroles can be controlled through stabilization of the vinylcarbenoid intermediates by neighboring group participation
Design and Evaluation of an Acceleration Guidance Algorithm for Entry

The design and performance evaluation of an entry guidance algorithm for future space transportation vehicles is presented. The guidance concept is to plan and track aerodynamic acceleration. This concept, on which the longitudinal entry guidance for the Space Shuttle Orbiter is based, is extended to integrated longitudinal and lateral guidance. With integrated longitudinal and lateral guidance, more extreme points in the landing footprint can be reached accurately; in particular, the cross-range capability is extended. The guidance algorithm consists of two components: a trajectory planner and a trajectory tracking law. The planner generates reference drag acceleration and heading angle profiles, along with reference state and bank angle profiles. The planner executes onboard and is capable of generating updates as the entry evolves. The tracking law, based on feedback linearization, commands the angles of bank and attack required to follow the reference drag and heading angle profiles. The planner and tracking law are described, along with additional higher level logic included in the algorithm. Extensive simulations for a set of return-from-orbit entries, including ones requiring large cross range, demonstrate that this algorithm consistently achieves the desired target conditions within allowable tolerances and satisfies all other entry constraints.
Photoelectron Spectroscopy and the Dipole Approximation

Over the past three decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Advances in gas-phase photoemission experiments using synchrotron radiation have recently highlighted nondipole effects at relatively low photon energies while probing the limits of the dipole approximation. Breakdowns in this approximation are manifested primarily as deviations from dipolar angular distributions of photoelectrons. Detailed new results demonstrate nondipolar angular-distribution effects are easily observable in atomic gases at energies well below 1 keV, and, in molecules, a previously unexpected phenomenon greatly enhances the breakdown of the dipole approximation just above the core-level ionization threshold.
Association of insurance status and ethnicity with cancer stage at diagnosis for 12 cancer sites: a retrospective analysis

Summary Background Individuals in the USA without private medical insurance are less likely to have access to medical care or participate in cancer screening programmes than those with private medical insurance. Smaller regional studies in the USA suggest that uninsured and Medicaid-insured individuals are more likely to present with advanced-stage cancer than privately insured patients; however, this finding has not been assessed using contemporary, national-level data. Furthermore, patients with cancer from ethnic minorities are more likely to be uninsured or Medicaid-insured than non-Hispanic white people. Separating the effects on stage of cancer at diagnosis associated with these two types of patient characteristics can be difficult. Methods Patients with cancer in the USA, diagnosed between 1998 and 2004, were identified using the US National Cancer Database—a hospital-based registry that contains patient information from about 1430 facilities. Odds ratios and 95% CIs for the effect of insurance status (Medicaid, Medicare (65–99 years), Medicare (18–64 years), private, or uninsured) and ethnicity (white, Hispanic, black, or other) on disease stage at diagnosis for 12 cancer sites (breast [female], colorectal, kidney, lung, melanoma, non-Hodgkin lymphoma, ovary, pancreas, prostate, urinary bladder, uterus, and thyroid) were estimated, while controlling for patient characteristics. Findings 3 742 407 patients were included in the analysis; patient characteristics were similar to those of the corresponding US population not included in the analysis. Uninsured and Medicaid-insured patients were significantly more likely to present with advanced-stage cancer compared with privately insured patients. This finding was most prominent for patients who had cancers that can potentially be detected early by screening or symptom assessment (eg, breast, colorectal, and lung cancer, as well as melanoma). For example, the odds ratios for advanced-stage disease (stage III or IV) at diagnosis for uninsured or Medicaid-insured patients with colorectal cancer were 2·0 (95% CI 1·9–2·1) and 1·6 (95% CI 1·5–1·7), respectively, compared with privately-insured patients. For advanced-stage melanoma, the odds ratios were 2·3 (2·1–2·5) for uninsured patients and 3·3 (3·0–3·6) for Medicaid-insured patients compared with privately insured patients. Black and Hispanic patients were noted to have an increased risk of advanced-stage disease (stage III or IV) at diagnosis, irrespective of insurance status, compared with White patients. Interpretation In this US-based analysis, uninsured and Medicaid-insured patients, and those from ethnic minorities, had substantially increased risks of presenting with advanced-stage cancers at diagnosis. Although many factors other than insurance status also affect the quality of care received, adequate insurance is a crucial factor for receiving appropriate cancer screening and timely access to medical care.
Gravity currents and internal waves in a stratified fluid

A steady theory is presented for gravity currents propagating with constant speed into a stratified fluid with a general density profile. Solution curves for front speed versus height have an energy-conserving upper bound (the conjugate state) and a lower bound marked by the onset of upstream influence. The conjugate state is the largest-amplitude nonlinear internal wave supported by the ambient stratification, and in the limit of weak stratification approaches Benjamin's energy-conserving gravity current solution. When the front speed becomes critical with respect to linear long waves generated above the current, steady solutions cannot be calculated, implying upstream influence. For non-uniform stratification, the critical long-wave speed exceeds the ambient long-wave speed, and the critical-Froude-number condition appropriate for uniform stratification must be generalized. The theoretical results demonstrate a clear connection between internal waves and gravity currents. The steady theory is also compared with non-hydrostatic numerical solutions of the full lock release initial-value problem. Some solutions resemble classic gravity currents with no upstream disturbance, but others show long internal waves propagating ahead of the gravity current. Wave generation generally occurs when the stratification and current speed are such that the steady gravity current theory fails. Thus the steady theory is consistent with the occurrence of either wave-generating or steady gravity solutions to the dam-break problem. When the available potential energy of the dam is large enough, the numerical simulations approach the energy-conserving conjugate state. Existing laboratory experiments for intrusions and gravity currents produced by full-depth lock exchange flows over a range of stratification profiles show excellent agreement with the conjugate state solutions.
Surrogate based optimization of helicopter rotor blades for vibration reduction in forward flight

The effectiveness of surrogate modeling of helicopter vibrations, and the use of the surrogates for minimization of helicopter rotor vibrations are studied. The accuracies of kriging, radial basis function interpolation, and polynomial regression surrogates are compared. In addition, the surrogates are used to generate an objective function which is employed in an optimization study. The design variables consist of the cross-sectional dimensions of the structural member of the blade and non-structural masses. The optimized blade is compared with a baseline rotor blade which resembles an MBB BO-105 blade. Results indicate that: (a) kriging surrogates best approximate vibratory hub loads over the entire design space and (b) the surrogates can be used effectively in helicopter rotor vibration reduction studies.
Sum rules for Jacobi matrices and their applications to spectral theory

We discuss the proof of and systematic application of Case's sum rules for Jacobi matrices. Of special interest is a linear combination of two of his sum rules which has strictly positive terms. Among our results are a complete classification of the spectral measures of all Jacobi matrices J for which J - J(0) is Hilbert-Schmidt, and a proof of Nevai's conjecture that the Szego condition holds if J - J(0) is trace class.
Formation of Cosmic Dust Bunnies

Planetary formation is an efficient process now thought to take place on a relatively short astronomical time scale. Recent observations have shown that the dust surrounding a protostar emits more efficiently at longer wavelengths as the protoplanetary disk evolves, suggesting that the dust particles are coagulating into fluffy aggregates, "much as dust bunnies form under a bed." One poorly understood problem in this coagulation process is the manner in which the micrometer-sized charged grains form the fractal aggregate structures now thought to be the precursors of protoplanetary disk evolution. This paper examines the characteristics of such fractal aggregates formed by the collision of spherical monomers and aggregates where the charge is distributed over the aggregate structure. The aggregates are free to rotate due to the collisions and dipole-dipole electrostatic interactions. Comparisons are made for different precursor size distributions and like-charged, oppositely charged, and neutral grains
A Rh‐Catalyzed C−H Insertion Reaction for the Oxidative Conversion of Carbamates to Oxazolidinones

Selective intramolecular alkane oxidations: an RhII carboxylate catalyzed C-H amination reaction facilitates the preparation of 1,2-amino alcohols from primary carbamates. The reaction is stereospecific, providing access to chiral α-branched amines from optically pure starting materials with no loss in enantiomeric excess.
California’s Hospital Fair Pricing Act Reduced The Prices Actually Paid By Uninsured Patients

California’s Hospital Fair Pricing Act, passed in 2006, aims to protect uninsured patients from paying hospital gross charges: the full, undiscounted prices based on each hospital’s chargemaster. In this study I examined how the law affects the net price actually paid by uninsured patients—a question critical for evaluating the law’s impact. I found that from 2004 to 2012 the net price actually paid by uninsured patients shrank from 6 percent higher than Medicare prices to 68 percent lower than Medicare prices; the adjusted collection ratio, essentially the amount the hospital actually collected for every dollar in gross price charged, for uninsured patients dropped from 32 percent to 11 percent; and although hospitals have been increasingly less able to generate revenues from uninsured patients, they have raised the proportion of services provided to them in relation to total services provided to all patients. The substantial protection provided to uninsured patients by the California Hospital Fair Prici...
Global solutions of nonlinear wave equations in time dependent inhomogeneous media

We consider the problem of small data global existence for a class of semilinear wave equations with null condition on a Lorentzian background \({(\mathbb{R}^{3 + 1}, g)}\) with a time dependent metric g coinciding with the Minkowski metric outside the cylinder \({\{(t, x) || x | \leq R\}}\). We show that the small data global existence result can be reduced to two integrated local energy estimates and demonstrate that these estimates work in the particular case when g is merely C1 close to the Minkowski metric. One of the novel aspects of this work is that it applies to equations on backgrounds which do not settle to any particular stationary metric.
Adaptive locks: Combining transactions and locks for efficient concurrency

Transactional memory is being advanced as an alternative to traditional lock-based synchronization for concurrent programming. Transactional memory simplifies the programming model and maximizes concurrency. At the same time, transactions can suffer from interference that causes them to often abort, from heavy overheads for memory accesses, and from expressiveness limitations (e.g., for I/O operations). In this paper we propose an adaptive locking technique that dynamically observes whether a critical section would be best executed transactionally or while holding a mutex lock. The critical new elements of our approach include the adaptivity logic and cost-benefit analysis, a low-overhead implementation of statistics collection and adaptive locking in a full C compiler, and an exposition of the effects on the programming model. In experiments with both micro and macrobenchmarks we found adaptive locks to consistently match or outperform the better of the two component mechanisms (mutexes or transactions). Compared to either mechanism alone, adaptive locks often provide 3-to-10x speedups. Additionally, adaptive locks simplify the programming model by reducing the need for fine-grained locking: with adaptive locks, the programmer can specify coarse-grained locking annotations and often achieve fine-grained locking performance due to the transactional memory mechanisms.
STRIPES AND SUPERCONDUCTIVITY IN CUPRATE SUPERCONDUCTORS

One type of order that has been observed to compete with superconductivity in cuprates involves alternating charge and antiferromagnetic stripes. Recent neutron scattering studies indicate that the magnetic excitation spectrum of a stripe-ordered sample is very similar to that observed in superconducting samples. In fact, it now appears that there may be a universal magnetic spectrum for the cuprates. One likely implication of this universal spectrum is that stripes of a dynamic form are present in the superconducting samples. On cooling through the superconducting transition temperature, a gap opens in the magnetic spectrum, and the weight lost at low energy piles up above the gap; the transition temperature is correlated with the size of the spin gap. Depending on the magnitude of the spin gap with respect to the magnetic spectrum, the enhanced magnetic scattering at low temperature can be either commensurate or incommensurate. Connections between stripe correlations and superconductivity are discussed.
EFFECTIVE RECRUITMENT AND RETENTION OF MINORITY RESEARCH PARTICIPANTS

▪ Abstract Our ability, as leaders in public health scholarship and practice, to achieve and measure progress in addressing racial/ethnic disparities in health status and health care is severely constrained by low levels of participation of racial/ethnic minority populations in health-related research. Confining our review to those minority groups federally defined as underrepresented (African Americans/blacks, Latinos/Hispanics, and Native Americans/American Indians), we identified 95 studies published between January 1999 and April 2005 describing methods of increasing minority enrollment and retention in research studies, more than three times the average annual output of scholarly work in this area during the prior 15-year period. Ten themes emerged from the 75 studies that were primarily descriptive. The remaining 20 studies, which directly analyzed the efficacy or effectiveness of recruitment/retention strategies, were examined in detail and provided useful insights related to four of the ten factor...
The Visual Display of Quantitative Information

The visual display of quantitative information , The visual display of quantitative information , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
Taylor approximation of incomplete Radner equilibrium models

In the setting of exponential investors and uncertainty governed by Brownian motions, we first prove the existence of an incomplete equilibrium for a general class of models. We then introduce a tractable class of exponential–quadratic models and prove that the corresponding incomplete equilibrium is characterized by a coupled set of Riccati equations. Finally, we prove that these exponential–quadratic models can be used to approximate the incomplete models we studied in the first part.
Measuring tie strength in implicit social networks

Given a set of people and a set of events attended by them, we address the problem of measuring connectedness or tie strength between each pair of persons. The underlying assumption is that attendance at mutual events gives an implicit social network between people. We take an axiomatic approach to this problem. Starting from a list of axioms, which a measure of tie strength must satisfy, we characterize functions that satisfy all the axioms. We then show that there is a range of tie-strength measures that satisfy this characterization.A measure of tie strength induces a ranking on the edges of the social network (and on the set of neighbors for every person). We show that for applications where the ranking, and not the absolute value of the tie strength, is the important thing about the measure, the axioms are equivalent to a natural partial order. To settle on a particular measure, we must make a non-obvious decision about extending this partial order to a total order. This decision is best left to particular applications. We also classify existing tie-strength measures according to the axioms that they satisfy; and observe that none of the "self-referential" tie-strength measures satisfy the axioms. In our experiments, we demonstrate the efficacy of our approach; show the completeness and soundness of our axioms, and present Kendall Tau Rank Correlation between various tie-strength measures.
The land use–climate change–energy nexus

Landscape ecology focuses on the spatial patterns and processes of ecological and human interactions. These patterns and processes are being altered by both changing resource-management practices of humans and changing climate conditions associated, in part, with increases in atmospheric concentrations of greenhouse gases. Dominant resource-extraction and land-management activities involve energy, and the use of fossil energy is one of the key drivers behind increasing greenhouse gas emissions as well as land-use changes. Alternative energy sources (such as wind, solar, nuclear, and bioenergy) are being explored to reduce greenhouse gas emission rates. Yet, energy production, including alternative-energy options, can have a wide range of effects on land productivity, surface cover, albedo, and other factors that affect carbon, water, and energy fluxes and, in turn, climate. Meanwhile, climate influences the potential output, relative efficiencies, and sustainability of alternative energy sources. Thus, land use, climate change, and energy choices are linked, and any comprehensive analysis in landscape ecology that considers one of these factors should be cognizant of these interactions. This analysis explores the implications of linkages between land use, climate hange, and energy and points out ecological patterns and processes that may be affected by their interactions.
The organic grid: self-organizing computation on a peer-to-peer network

Desktop grids have been used to perform some of the largest computations in the world and have the potential to grow by several more orders of magnitude. However, current approaches to utilizing desktop resources require either centralized servers or extensive knowledge of the underlying system, limiting their scalability. We propose a new design for desktop grids that relies on a self-organizing, fully decentralized approach to the organization of the computation. Our approach, called the organic grid, is a radical departure from current approaches and is modeled after the way complex biological systems organize themselves. Similar to current desktop grids, a large computational task is broken down into sufficiently small subtasks. Each subtask is encapsulated into a mobile agent, which is then released on the grid and discovers computational resources using autonomous behavior. In the process of "colonization" of available resources, the judicious design of the agent behavior produces the emergence of crucial properties of the computation that can be tailored to specific classes of applications. We demonstrate this concept with a reduced-scale proof-of-concept implementation that executes a data-intensive independent-task application on a set of heterogeneous, geographically distributed machines. We present a detailed exploration of the design space of our system and a performance evaluation of our implementation using metrics appropriate for assessing self-organizing desktop grids.
ERROR RATE IN CURRENT-CONTROLLED LOGIC PROCESSORS WITH SHOT NOISE

The error rate in a current-controlled logic microprocessor dominated by shot noise has been investigated. It is shown that the error rate increases very rapidly with increasing cutoff frequency. The maximum clock frequency of the processor, which works without errors, is obtained as a function of the operational current. The information channel capacity of the system is also studied.
Duality between channel capacity and rate distortion with two-sided state information

We show that the duality between channel capacity and data compression is retained when state information is available to the sender, to the receiver, to both, or to neither. We present a unified theory for eight special cases of channel capacity and rate distortion with state information, which also extends existing results to arbitrary pairs of independent and identically distributed (i.i.d.) correlated state information (S/sub 1/, S/sub 2/) available at the sender and at the receiver, respectively. In particular, the resulting general formula for channel capacity C = max/sub p/(u,x|s/sub 1/) [I(U; S/sub 2/, Y) I(U; S/sub 1/)] assumes the same form as the generalized Wyner-Ziv (1976) rate distortion function R(D) = min/sub p/(u|x, s/sub 1/)p(x/spl I.cap/|u, s/sub 2/) [I(U; S/sub 1/, X) 1(U; S/sub 2/)].
A new notion of transitivity for groups and sets of permutations

Let Ω = {1, 2 ,...,n } where n 2. The shape of an ordered set partition P =( P1 ,...,P k )o f Ω is the integer partition λ =( λ1 ,...,λ k) defined by λi = |Pi| .L etG be a group of permutations acting on Ω. For a fixed partition λ of n ,w e say thatG is λ-transitive if G has only one orbit when acting on partitions P of shape λ. A corresponding definition can also be given when G is just a set. For example, if λ =( nt, 1 ,..., 1), then a λ-transitive group is the same as a t-transitive permutation group, and if λ =( nt, t), then we recover the t-homogeneous permutation groups. We use the character theory of the symmetric group Sn to establish some structural results regarding λ-transitive groups and sets. In particular, we are able to generalize a celebrated result of Livingstone and Wagner (Math. Z. 90 (1965) 393-403) about t-homogeneous groups. We survey the relevant examples coming from groups. While it is known that a finite group of permutations can be at most 5-transitive unless it contains the alternating group, we show that it is possible to construct a nontrivial t-transitive set of permutations for each positive integer t .W e also show how these ideas lead to a combinatorial basis for the Bose-Mesner algebra of the association scheme of the symmetric group and a design system attached to this association scheme.
The Safety Organizing Scale Development and Validation of a Behavioral Measure of Safety Culture in Hospital Nursing Units

Background: Evidence that medical error is a systemic problem requiring systemic solutions continues to expand. Developing a “safety culture” is one potential strategy toward improving patient safety. A reliable and valid self-report measure of safety culture is needed that is both grounded in concrete behaviors and is positively related to patient safety. Objective: We sought to develop and test a self-report measure of safety organizing that captures the behaviors theorized to underlie a safety culture and demonstrates use for potentially improving patient safety as evidenced by fewer reported medication errors and patient falls. Subjects: A total of 1685 registered nurses from 125 nursing units in 13 hospitals in California, Indiana, Iowa, Maryland, Michigan, and Ohio completed questionnaires between December 2003 and June 2004. Research Design: The authors conducted a cross-sectional assessment of factor structure, dimensionality, and construct validity. Results: The Safety Organizing Scale (SOS), a 9-item unidimensional measure of self-reported behaviors enabling a safety culture, was found to have high internal reliability and reflect theoretically derived and empirically observed content domains. The measure was shown to discriminate between related concepts like organizational commitment and trust, vary significantly within hospitals, and was negatively associated with reported medication errors and patient falls in the subsequent 6-month period. Conclusions: The SOS not only provides meaningful, behavioral insight into the enactment of a safety culture, but because of the association between SOS scores and reported medication errors and patient falls, it also provides information that may be useful to registered nurses, nurse managers, hospital administrators, and governmental agencies.
Ultra-Low-Field Squid Magnetic Measurements on High Temperature Ceramic YBaCuO Superconductors

We report ultra-low-field (5 mOe - 1 Oe) magnetic measurements on a ceramic sample of YBaCuO. A positive remanent moment is observed which accurately equals the difference of the field-cooled and zero-field-cooled moments throughout the temperature range. At higher fields this relationship breaks down. A reversible region is observed near the superconducting transition temperature which is independent of field. These results are discussed in the context of recent models.
Refinements of the Chern-Dold character: cocycle additions in differential cohomology

The Chern-Dold character of a cohomology theory \(E\) is a canonical transformation \(E\rightarrow HV\) to ordinary cohomology. A spectrum representing \(E\) gives homotopy theoretic cocycles for \(E\), while \(HV\) can be represented by singular cocycles. We construct a refinement of the Chern-Dold character to a transformation of the cocycle categories that takes the homotopical composition to the addition of singular cocycles. This is applied to construct additive structures at the level of differential cocycles for generalized differential cohomology.
Variational Integrators for the Gravitational N-Body Problem

This paper describes a fourth-order integration algorithm for the gravitational N-body problem based on discrete Lagrangian mechanics. When used with shared time steps, the algorithm is momentum conserving and symplectic. We generalize the algorithm to handle individual time steps; this introduces fifth-order errors in angular momentum conservation and symplecticity. We show that using adaptive block-power-of-two time steps does not increase the error in symplecticity. In contrast to other high-order, symplectic, individual time step, momentum-preserving algorithms, the algorithm takes only forward time steps. We compare a code integrating an N-body system using the algorithm with a direct-summation force calculation to standard stellar cluster simulation codes. We find that our algorithm has about 1.5 orders of magnitude better symplecticity and momentum conservation errors than standard algorithms for equivalent numbers of force evaluations and equivalent energy conservation errors.
The nature of mathematical modeling

Preface 1. Introduction Part I. Analytical Models: 2. Ordinary differential and difference equations 3. Partial differential equations 4. Variational principles 5. Random systems Part II. Numerical Models: 6. Finite differences: ordinary difference equations 7. Finite differences: partial differential equations 8. Finite elements 9. Cellular automata and lattice gases Part III. Observational Models: 10. Function fitting 11. Transforms 12. Architectures 13. Optimization and search 14. Clustering and density estimation 15. Filtering and state estimation 16. Linear and nonlinear time series Appendix 1. Graphical and mathematical software Appendix 2. Network programming Appendix 3. Benchmarking Appendix 4. Problem solutions Bibliography.
GrassRoots: socially-driven web sites for the masses

Large, socially-driven Web 2.0 sites such as Facebook and Youtube have seen significant growth in popularity [5, 10]. However, strong demand also exists for socially-driven web sites specialized to companies and knowledge domains. Unfortunately, existing tools for building such sites only provide low-level functionality to address recurring search and organization patterns. Further, they require expertise at many levels of the software stack.Therefore, we propose GrassRoots, a declarative language for modeling socially-driven websites and a compiler to automatically generate the code at several layers of the software stack. We provide abstractions for modeling data and relationships, search, page composition, and navigation. Most notably, we propose a graph-based data model that allows designers to both filter and rank search results using structural and value-based primitives. In this paper, we describe the GrassRoots language and show how popular socially-driven websites can be specified using it. We also describe the GR compiler that generates web sites based on GrassRoots specifications.
Methodology of activity surveys to estimate mechanical loading on bones in humans

There is growing evidence from laboratory studies showing that regular physical activity with a sufficient level of intensity is an effective osteogenic stimulus.[3 and 6] However, little is known about how much activity in terms of frequency, intensity, and duration is needed to impact bone mass and what direct (e.g., age, gender, race) and indirect factors (e.g., diet, lifestyle habits, medications, environmental exposures) influence the relation between physical activity and bone health. [9. E.W. Gregg, M.A. Pereira and C.J. Caspersen , Physical activity, falls, and fractures among older adults: A review of the epidemiologic evidence. J Am Geriatr Soc 48 (2000), pp. 883–893. View Record in Scopus | Cited By in Scopus (130)9] One purpose of epidemiologic studies is to identify causal associations between exposures and disease outcomes.[25] For bone health, the causal association is between some level of physical activity and bone mass or bone mineral density (BMD). Bone mass and BMD in this study will be used interchangeably. Epidemiologic criteria for causality require evidence for the presence of a biologic mechanism, dose-response effect, and a statistically strong association between the exposure and the outcome. Furthermore, in epidemiologic studies, it must be shown that changes in exposure precede the outcome and that similar findings have been observed in several studies. [12] Because of the need for epidemiologic studies to generalize to population groups, large sample sizes are usually required. Accordingly, questionnaires are used to quantify physical activity as the exposure of interest. Most physical activity questionnaires focus on the recall of the frequency, intensity, duration, and type of activities performed during a particular time in the past.[13] Historically, questionnaires have been developed to identify the levels of activity needed to reduce the risk of chronic diseases, particularly cardiovascular disease. Few questionnaires have been developed to assess specifically the relation between historic physical activity and BMD. [15, 29 and 31] The purpose of this study is to explore methodologies that may be used to develop a questionnaire for measuring the association between mechanical loading applied to the skeleton through physical activity and BMD.
On Incentives and Updating in Agent Based Models

This paper introduces the concept of incentive based asynchronous updating in which the order of updating is determined by incentives. Previously, asynchronous updating has been shown to yield greater stability than synchromous updating for a variety of dynamical systems. However, in those models the order of updating is random. When incentives determine the ordering, the dynamics and end states change. For a conformity model on a two dimensional cellular automata, incentive based asynchronous updating yields greater linear disparity. Fot the game of life, it results in much greater sensitivity to initial conditions.
On Scheduling Fees to Prevent Merging, Splitting, and Transferring of Jobs

A deterministic server is shared by users with identical linear waiting costs, requesting jobs of arbitrary lengths. Shortest jobs are served first for efficiency. The server can monitor the length of a job but not the identity of the job's user, thus merging, splitting, or partially transferring jobs offer cooperative strategic opportunities. Can we design cash transfers to neutralize such manipulations? We prove that mergeproofness and splitproofness are not compatible, and that it is similarly impossible to prevent all transfers of jobs involving three or more agents. On the other hand, robustness against pairwise transfers is feasible and essentially characterizes a one-dimensional set of scheduling methods. This line is borne by two outstanding methods: the merge-proof S+ and the split-proof S-. Splitproofness, unlike mergeproofness, is not compatible with several simple tests of equity. Thus, the two properties are far from equally demanding.
Dynamically focused fuzzy learning control

A "learning system" possesses the capability to improve its performance over time by interacting with its environment. A learning control system is designed so that its "learning controller" has the ability to improve the performance of the closed-loop system by generating command inputs to the plant and utilizing feedback information from the plant. Learning controllers are often designed to mimic the manner in which a human in the control loop would learn how to control a system while it operates. Some characteristics of this human learning process may include: (i) a natural tendency for the human to focus their learning by paying particular attention to the current operating conditions of the system since these may be most relevant to determining how to enhance performance; (ii) after learning how to control the plant for some operating condition, if the operating conditions change, then the best way to control the system may have to be re-learned; and (iii) a human with a significant amount of experience at controlling the system in one operating region should not forget this experience if the operating condition changes. To mimic these types of human learning behavior, we introduce three strategies that can be used to dynamically focus a learning controller onto the current operating region of the system. We show how the subsequent "dynamically focused learning" (DFL) can be used to enhance the performance of the "fuzzy model reference learning controller" (FMRLC) and furthermore we perform comparative analysis with a conventional adaptive control technique. A magnetic ball suspension system is used throughout the paper to perform the comparative analyses, and to illustrate the concept of dynamically focused fuzzy learning control.
An O(bn/sup 2/) time algorithm for optimal buffer insertion with b buffer types

Buffer insertion is a popular technique to reduce the interconnect delay. The classic buffer insertion algorithm of van Ginneken has a time complexity of O(n/sup 2/), where n is the number of buffer positions. Lillis, Cheng, and Lin extended van Ginneken's algorithm to allow b buffer types in O(b/sup 2/n/sup 2/) time. For modern design libraries that contain hundreds of buffers, it is a serious challenge to balance the speed and performance of the buffer insertion algorithm. In this paper, we present a new algorithm that computes the optimal buffer insertion in O(bn/sup 2/) time. The reduction is achieved by the observation that the (Q,C) pairs of the candidates that generate the new candidates must form a convex hull. On industrial test cases, the new algorithm is faster than the previous best buffer insertion algorithms by orders of magnitude. Since van Ginneken's algorithm with multiple buffer types are used by most existing algorithms on buffer insertion and buffer sizing, our new algorithm improves the performance of all these algorithms.
The variable-dispersion spectrometer at the SCA/FEL

Abstract An electron spectrometer with dispersion variable between zero and 0.08%/mm has been installed on the SCA/FEL. At zero dispersion the energy acceptance is several percent. Spectral data can be acquired at a 30 kHz rate. Energy extraction by the FEL has been measured at 0.4%.
Body‐wave radiation patterns and AVO in transversely isotropic media

The angular dependence of reflection coefficients may be significantly distorted in the presence of elastic anisotropy. However, the influence of anisotropy on amplitude variation with offset (AVO) analysis is not limited to reflection coefficients. AVO signatures (e.g., AVO gradient) in anisotropic media are also distorted by the redistribution of energy along the wavefront of the wave traveling down to the reflector and back up to the surface. Significant anisotropy above the target horizon may be rather typical of sand‐shale sequences commonly encountered in AVO analysis. Here, I examine the influence of P‐ and S‐wave radiation patterns on AVO in the most common anisotropic model—transversely isotropic media. A concise analytic solution, obtained in the weak‐anisotropy approximation, provides a convenient way to estimate the impact of the distortions of the radiation patterns on AVO results. It is shown that the shape of the P‐wave radiation pattern in the range of angles most important to AVO analysis...
New photochemistry of cross-conjugated cyclohexadienones. Photocyclizations of 4-benzyloxymethyl- and 4-trimethylsilylmethoxymethyl-2,5-cyclohexadien-1-ones

Abstract Photocyclization reactions of 4-benzyloxymethyl- and 4-trimethylsilylmethoxymethyl-2,5-cyclohexadien-1-ones 6a and 6c to give 7 and 14 are described; the primary photochemical step is thought to be hedrogen atom transfer (6 → 10) and/or single electron transfer (6 → 11).
Do online reviews matter? - An empirical investigation of panel data

This study examines the persuasive effect and awareness effect of online user reviews on movies' daily box office performance. In contrast to earlier studies that take online user reviews as an exogenous factor, we consider reviews both influencing and influenced by movie sales. The consideration of the endogenous nature of online user reviews significantly changes the analysis. Our result shows that the rating of online user reviews has no significant impact on movies' box office revenues after accounting for the endogeneity, indicating that online user reviews have little persuasive effect on consumer purchase decisions. Nevertheless, we find that box office sales are significantly influenced by the volume of online posting, suggesting the importance of awareness effect. The finding of awareness effect for online user reviews is surprising as online reviews under the analysis are posted to the same website and are not expected to increase product awareness. We attribute the effect to online user reviews as an indicator of the intensity of underlying word-of-mouth that plays a dominant role in driving box office revenues.
Finding regulatory modules through large-scale gene-expression data analysis

Motivation: The use of gene microchips has enabled a rapid accumulation of gene-expression data. One of the major challenges of analyzing this data is the diversity, in both size and signal strength, of the various modules in the gene regulatory networks of organisms. Results: Based on the iterative signature algorithm [Bergmann,S., Ihmels,J. and Barkai,N. (2002) Phys. Rev. E67, 031902], we present an algorithm---the progressive iterative signature algorithm (PISA)---that, by sequentially eliminating modules, allows unsupervised identification of both large and small regulatory modules. We applied PISA to a large set of yeast gene-expression data, and, using the Gene Ontology database as a reference, found that the algorithm is much better able to identify regulatory modules than methods based on high-throughput transcription-factor binding experiments or on comparative genomics. Contact: [email protected]
Habitual Voting and Behavioral Turnout

Bendor, Diermeier, and Ting (2003) develop a behavioral alternative to rational choice models of turnout. However, the assumption they make about the way individuals adjust their probability of voting biases their model towards their main result of significant turnout in large populations. Moreover, the assumption causes individuals to engage in casual voting (sometimes people vote and sometimes they abstain). This result is at odds with a substantial literature that indicates most people engage in habitual voting (they either always vote or always abstain). I develop an alternative model to show how feedback in the probability adjustment mechanism affects the behavioral model. The version of this model without feedback yields both high turnout and habitual voting.