cssi/SciSciGPT-SciSciNet huggingface dataset:
Dimension reduction and alleviation of confounding for spatial generalized linear mixed models

Summary. Non-Gaussian spatial data are very common in many disciplines. For instance, count data are common in disease mapping, and binary data are common in ecology. When fitting spatial regressions for such data, one needs to account for dependence to ensure reliable inference for the regression coefficients. The spatial generalized linear mixed model offers a very popular and flexible approach to modelling such data, but this model suffers from two major shortcomings: variance inflation due to spatial confounding and high dimensional spatial random effects that make fully Bayesian inference for such models computationally challenging. We propose a new parameterization of the spatial generalized linear mixed model that alleviates spatial confounding and speeds computation by greatly reducing the dimension of the spatial random effects. We illustrate the application of our approach to simulated binary, count and Gaussian spatial data sets, and to a large infant mortality data set.
Lectures on Gromov invariants for symplectic 4-manifolds

Taubes’s recent spectacular work setting up a correspondence between J-holomorphic curves in symplectic 4-manifolds and solutions of the Seiberg-Witten equations counts J-holomorphic curves in a somewhat new way. The “standard” theory concerns itself with moduli spaces of connected curves, and gives rise to Gromov-Witten invariants: see for example, McDuff—Salamon [15], Ruan—Tian [20, 21]. However, Taubes’s curves arise as zero sets of sections and so need not be connected. These notes are in the main expository. We first discuss the invariants as Taubes defined them, and then discuss some alternatives, showing, for example, a way of dealing with multiply-covered exceptional spheres. We also calculate some examples, in particular finding the Gromov invariant of the fiber class of an elliptic surface by counting J-holomorphic curves, rather than going via Seiberg—Witten theory.
Democracy, Dictatorship and Economic Performance in Chile

The political and economic experience of Chile between 1932 and the present provides a natural experiment for a comparison of democracy and dictatorship with respect to their impact on economic performance. Democracy existed in Chile between 1932 and 1973, and was associated with a very wide range of efforts at economic reform, though without lasting success in any of them. This period also shows that democratic politics can provide economically perverse incentives, and can legitimately elect a president who carries out disastrous economic policies.
Session 1: Design

The session highlighted overarching themes that are characteristic of recent approaches to robot/mechanism design. These include: (i) flexibility of the design in order to address a wide spectrum of applications (e.g., a four-fingered hand that can deal with objects of various sizes, shapes, and masses); (ii) new materials that can really expand the design capabilities; (iii) bio-inspired approaches that yield highly innovative systems; and (iv) minimalistic systems that produce systems of low cost since fewer actuators than DOFs are utilized.
Link analysis tools for intelligence and counterterrorism

Association rule mining is an important data analysis tool that can be applied with success to a variety of domains. However, most association rule mining algorithms seek to discover statistically significant patterns (i.e. those with considerable support). We argue that, in law-enforcement, intelligence and counterterrorism work, sometimes it is necessary to look for patterns which do not have large support but are otherwise significant. Here we present some ideas on how to detect potentially interesting links that do not have strong support in a dataset. While deciding what is of interest must ultimately be done by a human analyst, our approach allows filtering some events with interesting characteristics among the many events with low support that may appear in a dataset.
Automating Type Soundness Proofs via Decision Procedures and Guided Reductions

Operational models of fragments of the Java Virtual Machine and the .NET Common Language Runtime have been the focus of considerable study in recent years, and of particular interest have been specifications and machine-checked proofs of type soundness. In this paper we aim to increase the level of automation used when checking type soundness for these formalizations. We present a semi-automated technique for reducing a range of type soundness problems to a form that can be automatically checked using a decidable first-order theory. Deciding problems within this fragment is exponential in theory but is often efficient in practice, and the time required for proof checking can be controlled by further hints from the user. We have applied this technique to two case studies, both of which are type soundness properties for subsets of the .NET CLR. These case studies have in turn aided us in our informal analysis of that system.
Sovereign natural disaster insurance for developing countries : a paradigm shift in catastrophe risk financing

Economic theory suggests that countries should ignore uncertainty for public investment and behave as if indifferent to risk because they can pool risks to a much greater extent than private investors can. This paper discusses the general economic theory in the case of developing countries. The analysis identifies several cases where the government's risk-neutral assumption does not hold, thus making rational the use of ex ante risk financing instruments, including sovereign insurance. The paper discusses the optimal level of sovereign insurance. It argues that, because sovereign insurance is usually more expensive than post-disaster financing, it should mainly cover immediate needs, while long-term expenditures should be financed through post-disaster financing (including ex post borrowing and tax increases). In other words, sovereign insurance should not aim at financing the long-term resource gap, but only the short-term liquidity need.
Do demand curves for stocks slope down?: Evidence from aggregate data

Abstract We examine whether the aggregate demand curve for stocks is downward sloping. As a proxy for aggregate demand, we use net outflows (dividends plus repurchases less net issues) from the stock market scaled by the previous year's market capitalization. To disentangle the information and price pressure effects from the demand curve effects, we use an information-free demographic variable as an instrument and look at the relation between annual changes in aggregate demand and excess market return. We find that information-free changes in the annual aggregate demand for stocks do not lead to changes in the annual excess market return. This finding supports long-term horizontal demand curves for stocks.
The least singular value of a random square matrix is O(n−1/2)

Abstract Let A be a matrix whose entries are real i.i.d. centered random variables with unit variance and suitable moment assumptions. Then the smallest singular value s n ( A ) is of order n − 1 / 2 with high probability. The lower estimate of this type was proved recently by the authors; in this Note we establish the matching upper estimate. To cite this article: M. Rudelson, R. Vershynin, C. R. Acad. Sci. Paris, Ser. I 346 (2008).
A COMPLETELY INSTRUMENTED SOLAR BUILDING: THE SHENANDOAH SOLAR RECREATIONAL CENTER

Publisher Summary This chapter presents an overview of the Shenandoah Solar Recreational Center—a completely instrumented solar building. The Shenandoah Solar Recreational Center, when completed early in 1977, was the world's largest building having most of its heating, air conditioning, and domestic hot water needs met by solar energy. The hydronic solar energy system uses demineralized water to transfer and store heat. The solar system was designed to provide a highly reliable system for efficient utilization of the available solar energy for heating, cooling, domestic water heating, and pool heating. The building incorporates 11,213 ft 2 of double glazed black chrome selectively coated copper tube-in-strip flat plate solar collectors oriented at an angle of 45° to the south with 23,000 ft 2 of highly polished aluminum reflectors to provide energy for heating and air conditioning the 59,000 ft 2 community center. Each of the 63 solar collectors is 8.61 ft high and 20.7 ft wide. Thermal storage is provided by 15,000 gal hot water storage tank, 2200 gal buffer tank, and two 30,000 gal chilled water storage tanks. The large tanks are buried beneath the earth berm surrounding the sides of the building. The building has been operating in all its modes since early April, 1977.
Micro-Market Determinants of Neighborhood Center Rental Rates

This investigation expands the limited empirical research on retail rental rates by investigating the determinants of neighborhood shopping center rents. Evidence supports primary trade area and pr...
Graph Decomposition and Parity

Motivated by a recent extension of the zero-one law by Kolaitis and Kopparty, we study the distribution of the number of copies of a fixed disconnected graph in the random graph Gn,p. We use an idea of graph decompositions to give a sufficient condition for this distribution to tend to uniform modulo q. We determine the asymptotic distribution of all fixed two-component graphs in Gn,p for all q, and we give infinite families of many-component graphs with a uniform asymptotic distribution for all q. We also prove a negative result that no recursive proof of the simplest form exists for a uniform asymptotic distribution for arbitrary graphs.
Ratio-of-Mediator-Probability Weighting for Causal Mediation Analysis in the Presence of Treatment-by-Mediator Interaction

Conventional methods for mediation analysis generate biased results when the mediator–outcome relationship depends on the treatment condition. This article shows how the ratio-of-mediator-probability weighting (RMPW) method can be used to decompose total effects into natural direct and indirect effects in the presence of treatment-by-mediator interactions. The indirect effect can be further decomposed into a pure indirect effect and a natural treatment-by-mediator interaction effect. Similar to other techniques for causal mediation analysis, RMPW generates causally valid results when the sequential ignorability assumptions hold. Yet unlike the model-based alternatives, including path analysis, structural equation modeling, and their latest extensions, RMPW requires relatively few assumptions about the distribution of the outcome, the distribution of the mediator, and the functional form of the outcome model. Correct specification of the propensity score models for the mediator remains crucial when paramet...
Crowding Out and Distributional Effects of FDI Policies

We analyze optimal host country policy toward multinational production in a three country model. Oligopolists from two source countries invest in a common host country to take advantage of low costs. The country with the smallest labor supply per firm has the highest wage in the absence of foreign direct investment (FDI). When FDI is allowed without intervention, wages become equalized across countries. Firms from the source country with the smallest labor supply per firm shift the most production into the host country as they enjoy the largest cost savings. We then examine the host country's optimal policy towards FDI. Any tax on multinationals can be thought of as the tax relative to domestic firms; any common tax across all firms merely bids up wages without shifting production. Hence, the main issue is whether foreign firms are taxed differently from each other. When free to discriminate, the host country imposes a higher tax on firms from the country with the stronger natural tendency to conduct FDI. A discriminatory tax on multinational production from one source encourages FDI from the favored source country while crowding out FDI from the disfavored source country. Such a tax also shifts rents across firms and alters wages in all countries. Firms from the favored source country benefit while firms from the other source country are harmed by the discriminatory treatment. Wages in the disfavored source country rise while those in the favored source country fall due the bias created in FDI toward originating from the favored source country. The source country subject to the larger tax would benefit from a nondiscrimination clause that requires the host country's FDI policy to treat all foreign firms equally. Source countries whose firms face the highest costs at home will push the hardest for multilateral agreements covering international investment.
Grammatical evolution of neural networks for discovering epistasis among quantitative trait loci

Growing interest and burgeoning technology for discovering genetic mechanisms that influence disease processes have ushered in a flood of genetic association studies over the last decade, yet little heritability in highly studied complex traits has been explained by genetic variation. Non-additive gene-gene interactions, which are not often explored, are thought to be one source of this “missing” heritability. Here we present our assessment of the performance of grammatical evolution to evolve neural networks (GENN) for discovering gene-gene interactions which contribute to a quantitative heritable trait. We present several modifications to the GENN procedure which result in modest improvements in performance.
An intelligent system for document retrieval in distributed office environments

MINDS (Multiple Intelligent Node Document Servers) is a distributed system of knowledge-based query engines for efficiently retrieving multimedia documents in an office environment of distributed workstations. By learning document distribution patterns, as well as user interests and preferences during system usage, it customizes document retrievals for each user. A two-layer learning system has been implemented for MINDS. The knowledge base used by the query engine is learned at the lower level with the help of heuristics for assigning credit and recommending adjustments; these heuristics are incrementally refined at the upper level.
The Theory of Successful Intelligence

This article presents a theory of successful intelligence. The theory is substantially broader than conventional theories of intelligence. It defines intelligence in terms of the ability to achieve one’s goals in life, within one’s sociocultural contex t. The article is divided into four major parts. The article opens with a consideration of the nature of intelligence. Then it discuss es measurement of intelligence. Next it discusses how people can be intelligent but foolish. Finally it draws conclusions.
Cooperative component-based software deployment in wireless ad hoc networks

This paper presents a middleware platform we designed in order to allow the deployment of component-based software applications on mobile devices (such as laptops or personal digital assistants) capable of ad hoc communication. This platform makes it possible to disseminate components based on peer-to-peer interactions between neighboring devices, without relying on any kind of infrastructure network. It implements a cooperative deployment scheme. Each device runs a deployment manager, which maintains a local component repository, and which strives to fill this repository with software components it is missing in order to satisfy the deployment requests expressed by the user. To achieve this goal the deployment manager continuously interacts in the background with peer managers located on neighboring devices, providing its neighbors with copies of software components it owns locally, while obtaining itself from these neighbors copies of the components it is looking for.
Cosmological Adaptive Mesh Refinement

The inclusion of hydrodynamics and atomic and radiation processes into cosmological structure formation simulations is essential for many applications of interest, including galaxy formation, the structure of the inter-galactic medium, formation and evolution of X-ray clusters, and cosmic reionization. A key technical challenge in such simulations is obtaining high mass and spatial resolution in collapsing structures within large cosmological volumes.
The Accelerating Universe and Dark Energy: Evidence from Type Ia Supernovae

� 0.1) demonstrate that the Hubble expansion is linear, that H0 = 72 ± 8 km s 1 Mpc 1 , and that the properties of dust in other galaxies are similar to those of dust in the Milky Way. The light curves of high-redshift (z = 0.3–1) SNe Ia are stretched in a manner consistent with the expansion of space; similarly, their spectra exhibit slower temporal evolution (by a factor of 1 + z) than those of nearby SNe Ia. The measured luminosity distances of SNe Ia as a function of redshift have shown that the expansion of the Universe is currently accelerating, probably due to the presence of repulsive dark energy such as Einstein’s cosmological constant (�). From about 200 SNe Ia, we find that H0t0 = 0.96 ± 0.04, and � 1.4M = 0.35 ± 0.14. Combining our data with the results of large-scale structure surveys, we find a best fit for M and � of 0.28 and 0.72, respectively — essentially identical to the recent WMAP results (and having comparable precision). The sum of the densities, � 1.0, agrees with extensive measurements of the cosmic microwave background radiation, including WMAP, and coincides with the value predicted by most inflationary models for the early Universe: the Universe is flat on large scales. A number of possible systematic effects (dust, supernova evolution) thus far do not seem to eliminate the need for � > 0. However, during the past few years some very peculiar low-redshift SNe Ia have been discovered, and we must be mindful of possible systematic effects if such objects are more abundant at high redshifts. Recently, analyses of SNe Ia at z = 1.0–1.7 provide further support for current acceleration, and give tentative evidence for an early epoch of deceleration. The dynamical age of the Universe is estimated to be 13.1±1.5 Gyr, consistent with the ages of globular star clusters and with the WMAP result of 13.7 ± 0.2 Gyr. Current projects include the search for additional SNe Ia at z > 1 to confirm the early deceleration, and the measurement of a few hundred SNe Ia at z = 0.2–0.8 to more accurately determine the equation of state of the dark energy, w = P/(�c 2 ), whose value is now constrained by SNe Ia to be in the range 1.48 < � w < � 0.72 at 95% confidence.
Inductive policy selection for first-order MDPs

We select policies for large Markov Decision Processes (MDPs) with compact first-order representations. We find policies that generalize well as the number of objects in the domain grows, potentially without bound. Existing dynamic-programming approaches based on flat, propositional, or first-order representations either are impractical here or do not naturally scale as the number of objects grows without bound. We implement and evaluate an alternative approach that induces first-order policies using training data constructed by solving small problem instances using PGraphplan (Blurn & Langford, 1999). Our policies are represented as ensembles of decision lists, using a taxonomic concept language. This approach extends the work of Martin and Geffner (2000) to stochastic domains, ensemble learning, and a wider variety of problems. Empirically, we find "good" policies for several stochastic first-order MDPs that are beyond the scope of previous approaches. We also discuss the application of this work to the relational reinforcement-learning problem.
Periodic orbits of Hamiltonian flows near symplectic critical submanifolds

In this paper we produce a lower bound for the number of periodic orbits of certain Hamiltonian vector fields near Bott-nondegenerate symplectic critical submanifolds. This result is then related to the problem of finding closed orbits of the motion of a charged low energy particle on a Riemannian manifold under the influence of a magnetic field
Perception of the Body in Space: Mechanisms

The sections in this article are: 1 Perception of Orientation Based on Multiple Sensory Modalities 1.1 Semicircular Canals 1.2 Otolith Organs 1.3 Somatosensory Cues 1.4 Limb Position 2 Psychophysical Measures of Perception of Orientation and Motion 3 Angular Acceleration 3.1 Rotation in Dark 3.2 Active Versus Passive Movement 3.3 Torsion-Pendulum Model 3.4 Thresholds 3.5 Oculogyral Illusion 3.6 Adaptation 3.7 Caloric and Alcohol Effects 4 Linear Motion and Gravity 4.1 Nature of Linear Accelerometers 4.2 Static Orientation to Vertical 4.3 Contributions of Nonlabyrinthine Sensors to Perception of Tilt 4.4 Reduced Somatosensory Cues 4.5 Labyrinthine Defective Subjects 4.6 Amplified Somatosensory or Postural Cues 5 Dynamic Response of Otolith System 5.1 Ambiguity of Subjective Response to Acceleration 5.2 Linear Acceleration Steps 5.3 Sinusoidal Linear Acceleration 6 Combined Rotational and Linear Accelerations 6.1 Consistent and Inconsistent Vestibular Signals 6.2 Centripetal Acceleration 6.3 Cross-Coupled Angular Accelerations; Coriolis Illusion 6.4 Rotation About Off-Vertical Axes 7 Visual Effects on Perceived Orientation—Models 7.1 Static Visual Orientation 7.2 Moving Visual Fields 7.3 Static Visual- Vestibular Interaction 7.4 Vection and Dynamic Visual-Vestibular Interaction 8 Spatial Orientation in Altered Environments 8.1 Motion Sickness 9 Summary
Asymptotics of Solutions of the Wave Equation on de Sitter-Schwarzschild Space

Solutions to the wave equation on de Sitter-Schwarzschild space with smooth initial data on a Cauchy surface are shown to decay exponentially to a constant at temporal infinity, with corresponding uniform decay on the appropriately compactified space.
Conversation as Action Under Uncertainty

Conversations abound with uncertainties of various kinds. Treating conversation as inference and decision making under uncertainty, we propose a task independent, multimodal architecture for supporting robust continuous spoken dialog called Quartet. We introduce four interdependent levels of analysis, and describe representations, inference procedures, and decision strategies for managing uncertainties within and between the levels. We highlight the approach by reviewing interactions between a user and two spoken dialog systems developed using the Quartet architecture: Presenter, a prototype system for navigating Microsoft PowerPoint presentations, and the Bayesian Receptionist, a prototype system for dealing with tasks typically handled by front desk receptionists at the Microsoft corporate campus.
On the Cohomology of Discriminantal Arrangements and Orlik–Solomon Algebras

We relate the cohomology of the Orlik-Solomon algebra of a discriminantal arrangement to the local system cohomology of the complement. The Orlik-Solomon algebra of such an arrangement (viewed as a complex) is shown to be a linear approximation of a complex arising from the fundamental group of the complement, the cohomology of which is isomorphic to that of the complement with coefficients in an arbitrary complex rank one local system. We also establish the relationship between the cohomology support loci of the complement of a discriminantal arrangement and the resonant varieties of its Orlik-Solomon algebra. Department of Mathematics Louisiana State University Baton Rouge, LA 70803 U. S. A. cohen@math.lsu.edu http://www.math.lsu.edu/~cohen 1991 Mathematics Subject Classification. Primary 52B30, 55N25; Secondary 20F36.
Cerulean: A Hybrid Assembly Using High Throughput Short and Long Reads

Genome assembly using high throughput data with short reads, arguably, remains an unresolvable task in repetitive genomes, since when the length of a repeat exceeds the read length, it becomes difficult to unambiguously connect the flanking regions. The emergence of third generation sequencing (Pacific Biosciences) with long reads enables the opportunity to resolve complicated repeats that could not be resolved by the short read data. However, these long reads have high error rate and it is an uphill task to assemble the genome without using additional high quality short reads. Recently, Koren et al. 2012 [1] proposed an approach to use high quality short reads data to correct these long reads and, thus, make the assembly from long reads possible. However, due to the large size of both dataset (short and long reads), error-correction of these long reads requires excessively high computational resources, even on small bacterial genomes. In this work, instead of error correction of long reads, we first assemble the short reads and later map these long reads on the assembly graph to resolve repeats.
GeoFramework: Coupling multiple models of mantle convection within a computational framework

Solver coupling can extend the capability of existing modeling software and provide a new venue to address previously intractable problems. A software package has been developed to couple geophysical solvers, demonstrating a method to accurately and efficiently solve multiscale geophysical problems with reengineered software using a computational framework (Pyre). Pyre is a modeling framework capable of handling all aspects of the specification and launching of numerical investigations. We restructured and ported CitcomS, a finite element code for mantle convection, into the Pyre framework. Two CitcomS solvers are coupled to investigate the interaction of a plume at high resolution with global mantle flow at low resolution. A comparison of the coupled models with parameterized models demonstrates the accuracy and efficiency of the coupled models and illustrates the limitations and utility of parameterized models.
ENERGY EFFICIENCY OPPORTUNITIES IN THE U.S. PULP AND PAPER INDUSTRY

The U.S. pulp and paper industry consumes over $7 billion worth of purchased fuels and electricity per year. Energy efficiency improvement is an important way to reduce these costs and to increase predictable earnings, especially in times of high energy price volatility. There are a variety of opportunities available at individual plants in the U.S. pulp and paper industry to reduce energy consumption in a cost-effective manner. This paper provides a brief overview of the U.S. EPA ENERGY STAR(R) for Industry energy efficiency guidebook (a.k.a. the Energy Guide ) for pulp and paper manufacturers. The Energy Guide discusses a wide range of energy efficiency practices and energy-efficient technologies that can be implemented at the component, process, facility, and organizational levels. Also provided is a discussion of the trends, structure, and energy consumption characteristics of the U.S. pulp and paper industry along with a description of the major process technologies used within the industry. Many energy efficiency measure descriptions include expected savings in energy and energy-related costs, based on case study data from real-world applications in pulp and paper mills and related industries worldwide. The information in this Energy Guide is intended to help energy and plant managers in the U.S. pulp and paper industry reduce energy consumption in a cost-effective manner while maintaining the quality of products manufactured. Further research on the economics of all measures?as well as on their applicability to different production practices?is needed to assess their cost effectiveness at individual plants.
The rising star formation histories of distant galaxies and implications for gas accretion with time

Distant galaxies show correlations between their current star formation rates (SFRs) and stellar masses, implying that their star formation histories (SFHs) are highly similar. Moreover, observations show that the ultraviolet luminosities and stellar masses grow from z = 8 to 3, implying that the SFRs increase with time. We compare the cosmologically averaged evolution in galaxies at 3 4 are as fast and may even exceed the SFR: this is the 'gas accretion epoch'. At z < 4 the SFR overtakes the implied gas accretion rate, indicating a period where galaxies consume gas faster than it is acquired. At z ≲ 3, galaxies with this number density depart from these relations implying that star formation and gas accretion are slowed at later times.
GRB 090510: a short burst from a massive star?

Gamma-ray burst (GRB) afterglow 090510 is (so far) the best-monitored afterglow in the optical, X-ray and above 100 MeV, measurements covering two–three decades in time at each frequency. Owing to its power-law temporal decay and power-law spectrum, it seems very likely that the highest energy emission is from the forward shock energizing the ambient medium (the standard blast-wave model for GRB afterglows), the GeV flux and its decay rate being consistent with that model’s expectations. However, the synchrotron emission from a collimated outflow (the standard jet model) has difficulties in accounting for the lower energy afterglow emission, where a simultaneous break occurs at 2 ks in the optical and X-ray light curves, but with the optical flux decay (before and after the break) being much slower than in the X-rays (at same time). The measured X-ray and GeV fluxes are incompatible with the higher energy afterglow emission being from same spectral component as the lower energy afterglow emission, which suggests a synchrotron self-Compton model for this afterglow. Cessation of energy injection in the blast wave and an ambient medium with a wind-like n∝r−2 density can explain all features of the optical and X-ray light curves of GRB afterglow 090510. Such an ambient medium radial structure is incompatible with this short GRB originating from the merger of two compact stars.
Limit on an Isotropic Diffuse Gamma-Ray Population with HAWC

Data from 105 days from the High Altitude Water Cherenkov Observatory (HAWC) have been used to place a new limit on an isotropic diffuse gamma-ray population above 10 TeV. Highenergy isotropic diffuse gamma-ray emission is produced by unresolved extragalactic objects such as active galactic nuclei, with potential contributio ns from interactions of high-energy cosmic rays with the inter-Galactic medium, or dark matter annihilation. Isotropic diffuse gamma-ray emission has been observed up to nearly 1 TeV. Above this energy, only upper limits have been reported. Observations or limits of the isotropic photon po pulation above these energies are very sensitive to local astrophysical particle production. Of p articular note, we expect a photon population to accompany the TeV-PeV astrophysical neutrino detection seen in the IceCube instrument. Observations or limits of a photon population above this energy can point to the origin of these neutrinos, indicating whether they are within the gamma-ray horizon or not. HAWC, with superior sensitivity to gamma rays between 100 GeV and 100 TeV, continuously observes the overhead sky and will measure or constrain isotropic emission above 1 TeV. We present a limit above 10 TeV based on the background rejection achieved in a 105-day observation of the Crab Nebula with HAWC. The limit will improve substantially with additional data and study.
On the Governance of Public Pension Fund Management

The author surveys the empirical literature on the relationship between governance of public pension fund management and investment performance. He makes a preliminary attempt to identify good governance practices and distill governance guidelines aimed at reducing the political risk that is associated with central, public pension fund management. The author highlights the need for further work to support the development of a satisfactory set of governance guidelines.
Weighted regret-based likelihood: a new approach to describing uncertainty

Recently, Halpern and Leung [8] suggested representing uncertainty by a weighted set of probability measures, and suggested a way of making decisions based on this representation of uncertainty: maximizing weighted regret. Their paper does not answer an apparently simpler question: what it means, according to this representation of uncertainty, for an event E to be more likely than an event E′. In this paper, a notion of comparative likelihood when uncertainty is represented by a weighted set of probability measures is defined. It generalizes the ordering defined by probability (and by lower probability) in a natural way; a generalization of upper probability can also be defined. A complete axiomatic characterization of this notion of regret-based likelihood is given.
AN ACTIVITY–ROTATION RELATIONSHIP AND KINEMATIC ANALYSIS OF NEARBY MID-TO-LATE-TYPE M DWARFS

Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by Hα emission), rotation period, and stellar age. Previous attempts to investigate the relationship between magnetic activity and rotation in these stars were hampered by the limited number of M dwarfs with measured rotation periods (and the fact that v sin i measurements probe only rapid rotation). However, the photometric data from MEarth allows us to probe a wide range of rotation periods for hundreds of M dwarf stars (from shorter than one to longer than 100 days). Over all M spectral types that we probe, we find that the presence of magnetic activity is tied to rotation, including for late-type, fully convective M dwarfs. We also find evidence that the fraction of late-type M dwarfs that are active may be higher at longer rotation periods compared to their early-type counterparts, with several active, late-type, slowly rotating stars present in our sample. Additionally, we find that all M dwarfs with rotation periods shorter than 26 days (early-type; M1–M4) and 86 days (late-type; M5–M8) are magnetically active. This potential mismatch suggests that the physical mechanisms that connect stellar rotation to chromospheric heating may be different in fully convective stars. A kinematic analysis suggests that the magnetically active, rapidly rotating stars are consistent with a kinematically young population, while slow-rotators are less active or inactive and appear to belong to an older, dynamically heated stellar population.
Ethics in Research

This review of research ethics provides a history of the regulation of research ethics and a summary of ethical issues including the recruitment of human participants, informed consent, debriefing, deception, avoiding harm, confidentiality, risk/benefit assessment, vulnerable populations, methodological issues, the use of animals, and ethical publication standards. Keywords: psychological research; human participants; ethical issues; research ethics
Latent dirichlet allocation

We describe latent Dirichlet allocation (LDA), a generative probabilistic model for collections of discrete data such as text corpora. LDA is a three-level hierarchical Bayesian model, in which each item of a collection is modeled as a finite mixture over an underlying set of topics. Each topic is, in turn, modeled as an infinite mixture over an underlying set of topic probabilities. In the context of text modeling, the topic probabilities provide an explicit representation of a document. We present efficient approximate inference techniques based on variational methods and an EM algorithm for empirical Bayes parameter estimation. We report results in document modeling, text classification, and collaborative filtering, comparing to a mixture of unigrams model and the probabilistic LSI model.
Evolution of geochemical variations along the Central American volcanic front

[1] New geochemical analyses of volcanic rocks in El Salvador add to existing data from Nicaragua and Costa Rica to create a comprehensive set of geochemical data for Central American volcanics. These data coupled with previously published 40Ar/39Ar ages covering the past 30 Ma show that Costa Rica and Nicaragua had similar U/Th and Ba/La values until 10 Ma when the region developed the distinctive along arc variations that made this margin famous. U/Th values increased in Nicaragua since the Miocene, while remaining unchanged along the rest of the volcanic front. This coincides temporally with the Carbonate Crash, which caused a transition in Cocos plate sediments from low-U carbonates to high-U, organic rich hemipelagic muds. Increases in uranium are not observed in Costa Rica because its lower slab dip produces a more diffuse zone of partial melting and because of the contribution from Galapagos-derived tracks dilutes this signal. Ba/La has been used as a geochemical proxy for contributions from the subducting slab; however, our analyses indicate that the Ba concentrations do not vary significantly along strike either in the subducting sediment or the volcanic front. Along-arc variation is controlled by changes in La, an indicator of the degree of partial melting or source enrichment. Trace element models of five segments of the volcanic front suggest that a subducting sediment component is more important to magmas produced in El Salvador and Nicaragua than in Costa Rica, where the geochemistry is controlled by recent (<10 Ma) recycling of Galapagos tracks.
Representation ring of Levi subgroups versus cohomology ring of flag varieties

Recall the classical result that the cup product structure constants for the singular cohomology with integral coefficients $$H^*({{\mathrm{\mathrm {Gr}}}}(r, n))$$ of the Grassmannian of r-planes coincide with the Littlewood-Richardson tensor product structure constants for $${{\mathrm{\mathrm {GL}}}}_r$$ . Specifically, the result asserts that there is an explicit surjective ring homomorphism $$\xi : {{\mathrm{\mathrm {Rep}}}}_{{{\mathrm{\mathrm {poly}}}}}({{\mathrm{\mathrm {GL}}}}_r) \rightarrow H^*({{\mathrm{\mathrm {Gr}}}}(r, n))$$ , where $${{\mathrm{\mathrm {Gr}}}}(r, n)$$ denotes the Grassmannian of r-planes in $$\mathbb {C}^n$$ and $${{\mathrm{\mathrm {Rep}}}}_{{{\mathrm{\mathrm {poly}}}}} ({{\mathrm{\mathrm {GL}}}}_r)$$ denotes the polynomial representation ring of $${{\mathrm{\mathrm {GL}}}}_r$$ . This work seeks to achieve one possible generalization of this classical result for $${{\mathrm{\mathrm {GL}}}}_r$$ and the Grassmannian $${{\mathrm{\mathrm {Gr}}}}(r,n)$$ to the Levi subgroups of any reductive group G and the corresponding flag varieties.
First Results from the All-Sky Monitor on the Rossi X-Ray Timing Explorer

The all-sky monitor on the Rossi X-Ray Timing Explorer has been monitoring the sky in the 1.5-12 keV band since late February. The instrument consists of three coded-aperture cameras that can be rotated to view different regions by a motorized drive assembly. Intensities of ~100 known sources are obtained via least-squares fits of shadow patterns to the data and compiled to form X-ray light curves. Six orbital periodicities and four long-term periodicities, all previously known, have been detected in these light curves. Searches for additional sources have also been conducted. X-ray light curves for the Crab Nebula, Cyg X-1, 4U 1705-44, GRO J1655-40, and SMC X-1 are reported. They illustrate the quality of the results and the range of observed phenomena.
Human Pluripotent Stem Cell-Derived Retinal Ganglion Cells: Applications for the Study and Treatment of Optic Neuropathies.

Retinal ganglion cells (RGCs) are highly specialized neuronal cells located in the innermost layer of the retina and serve to relay visual information to the brain, with their axons collectively forming the optic nerve. Loss or damage to the RGCs results in visual impairment and ultimately blindness. Several diseases affect the RGCs exclusively, the most common being glaucoma. Even though the mechanisms of glaucoma are not fully understood, some common treatments can delay cell death. Pharmacological intervention or laser therapy is thought to reduce the intraocular pressure and therefore reduce cell damage, but ultimately these therapies are often transient and stop working. Additional strategies to rescue RGCs and prevent their loss are being explored. Human pluripotent stem cells (hPSCs), including both embryonic and induced pluripotent stem cells, serve as an effective in vitro model of retinal development and repair. In addition, RGCs differentiated from hPSCs can also provide an unlimited source of transplantable cells for use in cell replacement strategies. This review addresses some of the technical and clinical issues and concerns with generating bone fide RGCs in vitro. We also outline the potential applications of hPSC-derived RGCs as a useful tool in disease modeling and drug screening in order to advance knowledge of optic neuropathies.
Normalizing Disability in Families

This comment shifts Ouellette's frame of reference in linking prenatal selection against disability, laws prohibiting prenatal sex selection, and fertility specialists' discrimination against disabled adults. Viewing decisions about who can reproduce and what children will be born as fundamentally decisions about family suggests ways to promote acceptance of people with disabilities as valued family members — without limiting reproductive liberties.
Supersymmetry Constraints and String Theory on K3

We study supervertices in six dimensional (2, 0) supergravity theories, and derive supersymmetry non-renormalization conditions on the 4- and 6-derivative four-point couplings of tensor multiplets. As an application, we obtain exact non-perturbative results of such effective couplings in type IIB string theory compactified on K3 surface, extending previous work on type II/heterotic duality. The weak coupling limit thereof, in particular, gives certain integrated four-point functions of half-BPS operators in the nonlinear sigma model on K3 surface, that depend nontrivially on the moduli, and capture worldsheet instanton contributions.
Localization of the domains of fibrin involved in binding to platelets.

Abstract The molecular basis of platelet-fibrin interactions has been investigated by using synthetic peptides as potential inhibitors of fibrin protofibril and fibrinogen binding to ADP-stimulated platelets, adhesion of fibrin fibers to the platelet surface, and platelet-mediated clot retraction. Synthetic peptides of sequence RGDS and HHLGGAKQAGDV, corresponding to regions of the fibrinogen α- and γ-chains previously identified as platelet recognition sites, inhibited the binding of radiolabelled soluble fibrin oligomers to ADP-stimulated platelets with IC 50 values of 10 and 40 μM, respectively. Synthetic GPRP and GHRP, corresponding to the N-terminal tripeptide sequence of the fibrin α-chains and the tetrapeptide sequence of the β-chains, respectively, were minimally effective in blocking soluble fibrin polymer binding to ADP-stimulated platelets. Platelet functions which are unique to the three-dimensional fibrin network were examined by measurements of the extent of adhesion of fluorophore-labelled fibrin to platelets with a microfluorimetric technique and by light scattering measurements of the time course of clot retraction. Inhibition of fibrin-platelet adhesion by RGDS, HHLGGAKQAGDV and GHRP exhibited a similar, linear dependence reaching 1 2 maximum at about 200 μM, suggesting nonspecific effects. GPRP inhibited fibrin assembly but did not appear to have specific effects on fibrin-platelet adhesion. Only RGDS effected clot retraction, causing a 4–6-fold decrease in rate at 230 μM. These results indicate that fibrinogen and fibrin protofibrils, which are obligatory intermediates on the fibrin assembly pathway, share a set of common platelet recognition sites located at specific regions of the α- and γ-chains of the multinodular fibrin(ogen) molecules. The RGDS site is also involved in mediating interactions between the three-dimensional fibrin network and stimulated platelets.
Deprotection of trimethylsilyl and tetrahydropyranyl ethers and of ethylene acetals with tetramethylammonium chlorochromate

This paper describes the preparation of tetramethylammonium chlorochromate (TMACC) as a new and efficient reagent for the oxidative deprotection of trimethylsilyl and tetrahydropyranyl ethers or ethylene acetals and ketals to the corresponding carbonyl compounds in refluxing acetonitrile in the presence of catalytic amounts of aluminum chloride.
On Gaussian random supergravity

We study the distribution of metastable vacua and the likelihood of slow roll inflation in high dimensional random landscapes. We consider two examples of landscapes: a Gaussian random potential and an effective supergravity potential defined via a Gaussian random superpotential and a trivial Kahler potential. To examine these landscapes we introduce a random matrix model that describes the correlations between various derivatives and we propose an efficient algorithm that allows for a numerical study of high dimensional random fields. Using these novel tools, we find that the vast majority of metastable critical points in N dimensional random supergravities are either approximately supersymmetric with |F| ≪ M susy or supersymmetric. Such approximately supersymmetric points are dynamical attractors in the landscape and the probability that a randomly chosen critical point is metastable scales as log(P ) ∝ − N. We argue that random supergravities lead to potentially interesting inflationary dynamics.
Data-Derived Symbol Synchronization of MASK and QASK Signals

Much has been said in the literature with regard to the problem of establishing symbol synchronization in binary baseband digital communication systems. By comparison, the literature contains little information relating to the extraction of symbol sync from multilevel baseband data. With the recent interest in multilevel amplitude-shift keying (MASK) and quadrature amplitude-shift keying (QASK) as signaling techniques for multilevel digital communications systems, the problem of providing symbol synchronization in the receivers of such systems becomes paramount. This paper presents a technique for extracting symbol sync from an MASK or QASK signal which has been transmitted over an infinite bandwidth white Gaussian noise channel. The scheme is essentially a generalization of the data transition tracking loop (DTTL) which has heretofore been used in PSK systems. The performance of the loop is analyzed in terms of its mean-squared symbol sync jitter and its effects on the data detection process in MASK and QASK systems.
Electrical Breakdown in Vacuum

In this paper vacuum breakdown phenomena are reviewed in two parts. The first considers the development of thought concerning electrical breakdown in vacuum with particular regard to field emission, interaction of cathode emission at the anode, and particle effects, including impurities. While Section 1 is basically historical, Section 2 considers these and other topics in the light of recent literature.
Propagation of fast partons in the nuclear medium

The color dipole approach has been applied in the target rest frame to address the issues of transverse momentum broadening and energy loss of a fast quark propagating in the nuclear medium. A recent application of the theory to the FermiLab E772/E866 experimental data, determining the rate of energy loss of a quark propagating in the medium to be 2 to 3 GeV/fm, will be reviewed. Calculations for the transverse momentum distribution will be presented, and the results will be compared to the E866 data. The theory will be shown to compare favorably to the data, and these results will be shown to suggest that the momentum broadening of a quark is about twice the generally accepted size.