cssi/SciSciGPT-SciSciNet huggingface dataset:
X-Ray and Optical Flux Ratio Anomalies in Quadruply Lensed Quasars. I. Zooming in on Quasar Emission Regions*

X-ray and optical observations of quadruply lensed quasars can provide a microarcsecond probe of the lensed quasar, corresponding to scale sizes of ~102-104 gravitational radii of the central black hole. This high angular resolution is achieved by taking advantage of microlensing by stars in the lensing galaxy. In this paper we use X-ray observations of 10 lensed quasars recorded with the Chandra X-Ray Observatory as well as corresponding optical data obtained with either the Hubble Space Telescope or ground-based optical telescopes. These are analyzed in a systematic and uniform way with emphasis on the flux ratio anomalies that are found relative to the predictions of smooth lens models. A comparison of the flux ratio anomalies between the X-ray and optical bands allows us to conclude that the optical emission regions of the lensed quasars are typically larger than expected from basic thin-disk models by factors of ~3-30.
Structural information from methyl internal rotation spectroscopy.

▪ Abstract The fundamental quantum mechanics, group theory, and spectroscopy of methyl torsional structure accompanying electronic transitions is presented. The origin of barriers to internal rotation and the interaction of the methyl with the π system via hyperconjugation are discussed. Because of the relationship between the methyl barrier and the π system, measurement of the CH3 properties provides structural information about the molecule. In para′-substituted p-methyl-t-stilbenes, barriers in the S1 state show a strong dependence on the substituent, substituent conformation, and involvement of the substituent in hydrogen bonding interaction. The methyl torsional barrier reflects these changes despite the distance of the substitution site, 10 atoms away.
First Principles Study of the Li–Bi–F Phase Diagram and Bismuth Fluoride Conversion Reactions with Lithium

First principles calculations have been used to explore the Li–Bi–F ternary phase diagram. Our results confirm the thermodynamic stability of previously observed phases and find no new phases in this system. Electrochemical voltage profiles for the reaction of Li and BiF3 are in reasonable agreement with experiment. The driving force to form ternary Li–Bi–F intermediates is small. We also investigated the effect of particle size on the reaction voltage and find a potential decrease when nanoscale vs bulk Bi forms
Long-range molecular resonances in a cold Rydberg gas

We have seen spectral evidence for long-range molecular resonances involving pairs of cold Rydberg atoms. We attribute these features to avoided crossings between Rydberg-Rydberg long-range molecular interaction potentials.
Predictability and Transaction Costs: The Impact on Rebalancing Rules and Behavior

Recent papers show that predictability calibrated to U.S. data has a large effect on the rebalancing behavior of a multiperiod investor. We find that this continues to be true in the presence of realistic transaction costs. In particular, predictability causes the no-trade region for the risky-asset holding to become state dependent and, on average, wider and higher. Predictability also motivates the investor to spend considerably more on rebalancing and to rebalance more often. In other results, we find that introducing costly liquidation of the risky asset for consumption lowers the average allocation to the risky asset, though only marginally early in life. Our experiments also vary the nature of the return predictability and introduce return heteroskedasticity. WE EXAMINE THE PORTFOLIO DECISIONS of a long-lived investor with constant relative risk aversion (CRRA) in the presence of transaction costs. Two types of costs are evaluated: proportional to the change in the holding of the risky asset and a fixed fraction of portfolio value. With a constant opportunity set, it is well known that these costs induce optimal rebalancing rules that involve a no-trade region for the CRRA investor's risky-asset holding. When the investor's holding goes outside the no-trade region, the investor rebalances to the closest boundary (proportional cost only) or to a point inside the region (nonzero fixed cost).1 In this paper, we focus on how return predictability affects portfolio choice and rebalancing behavior when transaction costs are nonzero. Recent papers show that predictability calibrated to U.S. data has a large effect on the rebalancing behavior of a multiperiod investor. We find that this continues to be true in the presence of realistic transaction costs. When
Vapor synthesis of titania powder by titanium tetrachloride oxidation

Formation of titania particles by vapor-phase oxidation of titanium tetrachloride was studied in an aerosol reactor between 1,200 and 1,723 K. The effect of process variables (reactor residence time, temperature, and reactant concentration) on powder size and phase characteristic was investigated using the differential mobility particle sizer, scanning electron microscopy, and X-ray diffraction. Titania particles were primarily anatase though the rutile weight fraction increased with increasing reactor temperature. The geometric number average diameter of the particles was between 0.13 and 0.35 μm, and the geometric standard deviation of the particle size distribution was about 1.4. The average particle size increased with increasing temperature, inlet TiCl4 concentration, and residence time. The observed changes in the particle size distribution were compared with those predicted by solving the aerosol dynamic equation by a sectional method and accounting for coagulation and first-order chemical reaction. While variations in the process variables resulted in discernible changes in the size of the particles, the spread of the distribution remained rather unaffected.
Overoptimism and the Performance of Entrepreneurial Firms

Recent theoretical and empirical research on cognitive bias in decision making suggests that overoptimism critically influences entrepreneurs decisions to establish and sustain new ventures. We investigate whether such cognitive bias influences entrepreneurial venture performance using data on commercialization efforts for university inventions. In contrast to prior studies, our results suggest that entrepreneurial overoptimism does not appear to be the determining factor in the decision to found a firm. We do find that entrepreneurs continue unsuccessful development efforts for longer periods of time than do established firms, which is consistent with entrepreneurial overoptimism in the development of technologies with uncertain market prospects. This latter finding is also consistent with rationality-based models of decision-making behavior, however. We find that the economic returns associated with many of the technologies in our sample are realized after the start-up has been acquired by an established firm, suggesting that start-ups may serve as a transitional organizational form in the market for technology commercialization.
A nonlocal theory of sediment buffering and bedrock channel evolution

[1] Bedrock erosion in mountain river channels ultimately sets the erosion rate of the surrounding hillslopes and the rate of sediment supply to the channels. The supply of coarse bed sediment acts as a dampening effect on further erosion by depositing an alluvial cover that temporarily obscures the bedrock. For landscapes where the residence time of the alluvial bed cover is comparable to the timescale of bedrock incision, coarse sediment supply and transport generate a strong negative feedback on fluvial downcutting and the coupled process of hillslope-channel erosion is inherently self-buffering. Here we study a simple model of self-buffered bedrock channel erosion that incorporates the spreading of bed sediment cover downstream in a way that allows for a broad-tailed, power law probability distribution of transport velocities of bed sediment over the long-term. This leads us to consider a nonlocal transport law (fractional advection) parameterized by a scaling exponent 0 ≤ α < 1 which collapses to local advection for α → 1. For strong sediment buffering, we find that nonlocality 1 − α has a direct control on the power law scaling of channel slope S with upstream area A, giving S ∼ A−(1−α)/2 at steady state. Empirical observations of slope-area scaling are consistent with α < 1 and nonlocal transport. In general, the model predicts linear, logarithmic, or power law stream profiles depending on the extent of buffering, the degree of nonlocality, and the scaling of the bedrock erosion law. It also predicts, somewhat counterintuitively, that bed cover should thicken with distance x downstream slower than linearly as xα, i.e., the more nonlocal the bed sediment spreading process (α → 0), the slower the bed cover increases downstream. We deduce that long-range, heterogeneous transport of coarse sediment in mixed bedrock-alluvial rivers may be a key element of landscape scaling and an important factor in landscape dynamics.
Simulation of Drosophila Circadian Oscillations, Mutations, and Light Responses by a Model with VRI, PDP-1, and CLK

A model of Drosophila circadian rhythm generation was developed to represent feedback loops based on transcriptional regulation of per, Clk (dclock), Pdp-1, and vri (vrille). The model postulates that histone acetylation kinetics make transcriptional activation a nonlinear function of [CLK]. Such a nonlinearity is essential to simulate robust circadian oscillations of transcription in our model and in previous models. Simulations suggest that two positive feedback loops involving Clk are not essential for oscillations, because oscillations of [PER] were preserved when Clk, vri, or Pdp-1 expression was fixed. However, eliminating positive feedback by fixing vri expression altered the oscillation period. Eliminating the negative feedback loop in which PER represses per expression abolished oscillations. Simulations of per or Clk null mutations, of per overexpression, and of vri, Clk, or Pdp-1 heterozygous null mutations altered model behavior in ways similar to experimental data. The model simulated a photic phase-response curve resembling experimental curves, and oscillations entrained to simulated light-dark cycles. Temperature compensation of oscillation period could be simulated if temperature elevation slowed PER nuclear entry or PER phosphorylation. The model makes experimental predictions, some of which could be tested in transgenic Drosophila.
Photometer for Luminescent Materials

In evaluating the usefulness of luminescent materials it is necessary to take into account the behavior of the human eye at low values of luminance. A photometer that provides for the determination of low luminances, with due regard for the characteristic behavior of the eye at such values, is described. It is interesting to note that both the luminescent materials and some of the phenomena of vision for the nearly dark-adapted eye have been known for many years, although the use of modern lamps to produce higher and higher illuminations has made it generally unnecessary to consider these phenomena. However, the use of the airplane for bombing with the counter measure of blacking out as a means of passive defense and the need for markers in the interiors of blacked-out ships have shown many of the luminescent materials to be practical instead of merely novel, and has led to development of methods for measuring the luminances which they yield.
It’s the Thought That Counts: On Perceiving How Helpers Decide to Lend a Hand

How do people react to those who have helped them? The authors propose that a recipient’s evaluation of a helper’s intentions and the recipient’s own attitudes about future interactions with the helper depend partly on the recipient’s perceptions of how the helper decided to assist: on the basis of affect, of role, or of cost-benefit calculation. When a recipient perceives that the decision was based on affect (i.e., positive feelings about him or her), he or she will be more inclined toward future interaction and reciprocation than if he or she perceives the decision as based on role or cost-benefit calculation. It is proposed that these “decision modes” signal the helper’s underlying attitudes about the recipient, which in turn, clarify their relationship. A boundary is also identified: The negative impact of apparent cost-benefit thinking is greatest when the amount of help provided is small. Predictions are confirmed in four studies of actual and experimentally manipulated helping episodes.
The Price of Selfishness in Network Coding

A game-theoretic framework is introduced for studying selfish user behavior in shared wireless networks. The investigation treats an n-unicast problem in a wireless network that employs a restricted form of network coding called reverse carpooling. Unicast sessions independently choose routes through the network. The cost of a set of unicast routes is the number of wireless transmissions required to establish those connections using those routes. Game theory is employed as a tool for analyzing the impact of cost sharing mechanisms on the global system performance when each unicast independently and selfishly chooses its route to minimize its individual cost. The investigation focuses on the performance of stable solutions, where a stable solution is one in which no single unicast can improve its individual cost by changing its route. The results include bounds on the best- and worst-case stable solutions compared to the best performance that could be found and implemented using a centralized controller. The optimal cost sharing protocol is derived and the worst-case solution is bounded. That worst-case stable performance cannot be improved using cost-sharing protocols that are independent of the network structure.
Asymmetric Organic Catalysis with Modified Cinchona Alkaloids

Insights into the role played by modified cinchona alkaloids in the Sharpless asymmetric dihydroxylation inspired studies of modified cinchona alkaloids as chiral organic catalysts that lead to the development of highly enantioselective alcoholyses for the desymmetrization, kinetic resolution, and dynamic kinetic resolution of cyclic anhydrides, cyanation of ketones, and 1,4-addition of thiols to cylic enones. These studies demonstrate the potential of modified cinchona alkaloids as broadly useful chiral organic catalysts for asymmetric synthesis.
A Fundamental, Relativistic and Irreversible Law of Motion: A Unification of Newton's Second Law of Motion and the Second Law of Thermodynamics

Temperature is an outsider in the laws of motion gi ven by Newton and Einstein and this oversight is th e source of the predictions of time-reversal-invariance made by the se two great systems of motion. By taking into consi deration Planck’s law of blackbody radiation and the Doppler effect, in thinking about Maxwell’s electromagnetic wave equation, I have shown that photons, in the environment through which any charged particle moves, act as a source of te mperature-dependent friction on everything from elementary particles to galaxies. Because the optomechanical friction is un iversal and inevitable, no real systems are conservative, and temperature c an no longer be an outsider in a fundamental and ir reducible law of motion. I have defined the change of entropy ( �S) in irreversible systems at constant temperature i n terms of the optomechanical friction. The Second Law of Thermodynamics, which states that �� > 0 for spontaneous processes, is explained by electromagnetic interactions between c harged particles and the Doppler-shifted photons th rough which they move as opposed to chance and statistics. �� , as defined here, is not subject to Poincare’s rec urrence theorem. Consequently, the Second Law of Thermodynamics is shown to be a fundamental law rather than a statistical law. This result, which supports the idea that every instant of time is uni que, is consistent with intuition and the routine e xperience of botanists. “Sometimes I dread the results of universal educati on. We become so indoctrinated with traditional idea s which may not be true, and we become so humble before the imposing pr estige of accepted professional opinion, that we los e the power of independent creative thinking. We need a ‘Society f or the Preservation of Ignorance,’ so that occasion ally someone…may
Problem-based learning as applied to the construction and engineering capstone course at North Dakota State University

North Dakota State University (NDSU) was the recent recipient of a Bush Grant for providing support and training for NDSU faculty. As part of that grant, the "Faculty Institute for Excellence in Learning" (FIEL) was created. The author was selected as a FIEL "Fellow" and subsequently submitted a proposal and received funding to apply a problem-based learning approach to the departmental capstone course. During the summer of 2001, the capstone course was revised and restructured to meet the primary objective of the course. The basic philosophy, format, evaluation and assessment of the course came into question. The contents of this paper: (1) describe some of the philosophical questions that had to be addressed; (2) provide an overview of problem-based learning; (3) explain the revised course content and delivery systems; and (4) provide an explanation of the techniques used to evaluate student work and provide course assessment.
Symmetry breaking and axionic strings in the warped deformed conifold

We interpret D-strings at the bottom of the warped deformed conifold as axionic strings in the dual cascading SU(N + M) × SU(N) gauge theory. The axion is a massless pseudo-scalar glueball which we find in the supergravity fluctuation spectrum and interpret as the Goldstone boson of spontaneously broken U(1) baryon number symmetry. The existence of this massless glueball, anticipated in hep-th/0101013, supports the idea that the cascading gauge theory is on the baryonic branch, i.e. the U(1)B global symmetry is broken by expectation values of baryonic operators. We also find a massless scalar glueball, which is a superpartner of the pseudo-scalar. This scalar mode is a mixture of an NS-NS 2-form and a metric perturbation of the warped deformed conifold of a type first considered in hep-th/0012034.
Cyclic 1,2-Diketones as Core Building Blocks: A Strategy for the Total Synthesis of (−)-Terpestacin

We report a full account of our work towards the total synthesis of (−)-terpestacin (1), a sesterterpene originally isolated from fungal strain Arthrinium sp. FA1744. Its promising anti-HIV and anti-cancer activity, as well as its novel structure, make terpestacin an attractive synthetic target. A strategy based on the unique reactivity of cyclic 1,2-diketones (diosphenols) was developed and total synthesis of 1 was achieved in 20 steps, in the longest linear sequence, from commercially available 2-hydroxy-3-methyl-2-cyclopenten-1-one. The key feature of our synthesis is the double usage of a “Pd AAA-Claisen” protocol (AAA=asymmetric allylic alkylation), first in the early stages to generate the C1 quaternary center and then in the late stages to install the side chain. In addition, a rather unusual ene-1,2-dione moiety was synthesized and utilized as an excellent Michael acceptor to attach the C15 substituent. Several possible routes towards the total synthesis have been examined and carefully evaluated. During our exploration many interesting chemoselectivity issues have been addressed, such as a highly selective ring-closing metathesis and a challenging oxidation of a disubstituted olefin in the presence of three trisubstiuted ones.
Determination of the Baryon Density from Large-Scale Galaxy Redshift Surveys

We estimate the degree to which the baryon density, Ωb, can be determined from the galaxy power spectrum measured from large-scale galaxy redshift surveys, and in particular, the Sloan Digital Sky Survey. A high baryon density will cause wiggles to appear in the power spectrum, which should be observable at the current epoch. We assume linear theory on scales ≥20 h-1 Mpc and do not include the effects of redshift distortions, evolution, or biasing. With an optimum estimate of P(k) to k ~ 2π/(20 h-1 Mpc), the 1 σ uncertainties in Ωb are roughly 0.07 and 0.016 in flat and open (Ω0 = 0.3) cosmological models, respectively. This result suggests that it should be possible to test for consistency with big bang nucleosynthesis estimates of Ωb if we live in an open universe.
Trapped-Vortex in Ground Effect

The effects of vortices trapped between a flat plate and a ground plane were studied in a wind tunnel experiment. The flat plate was mounted parallel to the ground to represent the lower surface of a generic road vehicle. Rectangular vortex generators mounted onto the plate were used to generate streamwise vortices between the plate and the ground plane. The main variables investigated were the ground clearance and vortex generator orientation, both influencing the trapped vortex strength. The experimental data indicates that considerable aerodynamic loads can be created with such vortex generators, particularly for small ground clearance values (even at zero plate incidence).
Traceability and Identity Preservation Policy: Private Initiatives vs. Public Intervention

Firms within the food supply chain must decide what information to provide and how to provide it. This applies to collecting information from upstream suppliers as well as to supplying information to downstream customers. Components of this vertical information situation include farmer supplier identity preservation to capture value and the buyer information needs concerning geographic location of production or seller identity in order to manage risk. A policy question is raised as to how vertical information flow; in the form of segregation, traceability, or identity preservation, should be accomplished. This question has recently come to the policy forefront through European labeling/traceability issues, the Canadian BSE incident, Country of Origin Labeling legislation, and biosecurity concerns. The US food industry often contends that mandated macro government systems (e.g. full traceability systems, animal passports, ISO 9000) would be misplaced and ineffective. They point to the tremendous private quality control systems, already in place in the industry. Though the industry's quality systems may not be in the public domain as in Europe, they are nonetheless present. The argument continues that proprietary systems contribute to a firm's competitive advantage and mandating a system would distort investment and incentives. Within this classic debate about public policy versus private strategies is a fundamental question about the role of commodities in the economy. Are they an inferior form of market development whereby the natural and preferred tendency is for supply to differentiate? Put another way is the economy better off with differentiated or undifferentiated (commodity) basic inputs? This article contributes to the policy debate by discussing why and how commodities many times are preferred by end users and thereby a signal of a properly performing economy not a market "failure." The discussion will also shed light on why farmer premiums remain low and how greater value can be created at the production stage.
Decoherence, einselection and the existential interpretation (the rough guide)

The roles of decoherence and environmentinduced superselection in the emergence of the classical from the quantum substrate are described. The stability of correlations between the einselected quan...
VALUES IN SCIENCE

In this essay, which was his presidential address to the Philosophy of Science Association, Ernan McMullin argued that the watershed between “classic” philosophy of science (by this meaning, not just logical positivism but the logicist tradition in theory of science stretching back through Kant and Descartes to Aristotle) and the “new” philosophy of science can best be understood by analyzing the change in our perception of the role played by values in science. He begins with some general remarks about the nature of value, goes on to explore some of the historical sources for the claim that judgement in science is value-laden, and concludes by reflecting on the implications of this claim for traditional views of the objectivity of scientific knowledge-claims.
The Mobilization of Opposition to Economic Liberalization

Opposition to economic liberalization has intensified since the late 1990s, with Latin America often standing at the forefront of new social and political movements that challenge market globalization. The revival of social protest and populist or leftist political alternatives has shattered the technocratic consensus around neoliberal policies in the region. By demanding an expanded set of social citizenship rights, these movements are also contesting the terms under which popular sectors were reincorporated politically under the new democratic regimes of the 1980s. This “second” historical process of mass political incorporation differs in fundamental ways from that associated with the process of labor incorporation in the first half of the twentieth century. It is marked by a more pluralistic set of social subjects, a more decentralized organizational structure, and more fluid patterns of institutional development. Existing scholarship often fails to explain variation in the patterns of social and poli...
GEOMETRIC REALIZATION AND K-THEORETIC DECOMPOSITION OF C*-ALGEBRAS

Suppose that A is a separable C*-algebra and that G* is a (graded) subgroup of the ℤ/2-graded group K*(A). Then there is a natural short exact sequence In this note we demonstrate how to geometrically realize this sequence at the level of C*-algebras. We KK-theoretically decompose A as where K*(At) is the torsion subgroup of K*(A) and K*(Af) is its torsionfree quotient. Then we further decompose At: it is KK-equivalent to ⊕p Ap where K*(Ap) is the p-primary subgroup of the torsion subgroup of K*(A). We then apply this realization to study the Kasparov group K*(A) and related objects.
International Tax as International Law

The purpose of this article is to introduce to the international lawyer the somewhat different set of categories (e.g., residence and source rather than nationality and territoriality) employed by international tax lawyers, and explain the reasons for some of the differences. At the same time, it attempts to persuade practicing international tax lawyers and international tax academics that their field is indeed part of international law, and that it would help them to think of it this way. For example, knowledge of the Vienna Convention on the Law of Treaties would help international tax lawyers in interpreting tax treaties, and avoid some common mistakes.
Intramolecular Free-Radical Cyclization An Approach to Hydrindanone Systems

Abstract A SmI2 promoted cyclization of the keto aldehydes 6 in the presence of tetraglyme to afford trans -7a-methyl-1,5-hydrindanedione is reported.
Trade Crisis and Recovery : Restructuring of Global Value Chains

The recent large and rapid slowdown in economic activity has resulted in even larger and more rapid declines in international trade. As world trade is set to rebound, this paper addresses three questions: (i) Will trade volumes rebound in a symmetric fashion as world economic growth rebounds? (ii) Will the crisis result in a change in the structure of trade, and in particular will it lead to a reversal of the pattern of more diversified sourcing and thus to a consolidation of global value chains? (iii) What policies can improve the prospects for developing country growth in the event that trade volumes do not rebound symmetrically and there is a consolidation of some global value chains?
Toward alternative metrics of journal impact: a comparison of download and citation data

We generated networks of journal relationships from citation and download data, and determined journal impact rankings from these networks using a set of social network centrality metrics. The resulting journal impact rankings were compared to the ISI IF. Results indicate that, although social network metrics and ISI IF rankings deviate moderately for citation-based journal networks, they differ considerably for journal networks derived from download data. We believe the results represent a unique aspect of general journal impact that is not captured by the ISI IF. These results furthermore raise questions regarding the validity of the ISI IF as the sole assessment of journal impact, and suggest the possibility of devising impact metrics based on usage information in general.
AIDS: advanced interactive display system

Faced with the problem of developing a multiterminal interactive graphics display system, analysis of past experience led to three specific problem areas which must be addressed in order to build a workable system. Not necessarily in order of importance or complexity these areas are (1) the difficulty in specifying interaction between the user and the computer, (2) the complexity of handling large quantities of graphic data and its interrelationship with the display hardware, and (3) the need to get away from assembly (or assembly type) languages so that one need not be a senior systems programmer in order to write a graphics program.
A symmetry-induced model of elliptical galaxy patterns

Sersic (Atlas de Galaxias Australes, Observatorio Astronomico, 1968) generalized the de Vaucouleurs law which follows the projected (observed) one dimensional radial profile of elliptical galaxies closely and Dehnen (Mon. Not. R. Astron. Soc. 265:250, 1993) proposed an analytical formula of the 3-dimensional light distributions whose projected line profile resembles the de Vaucouleurs law. This paper is involved to recover the Dehnen model and generalize the model to account for galaxy elliptical shapes by means of curvilinear coordinate systems and employing a symmetry principle. The symmetry principle maps an orthogonal coordinate system to a light distribution pattern. The coordinate system for elliptical galaxy patterns turns out to be the one which is formed by the complex-plane reciprocal transformation Z=1/W. The resulting spatial (3-dimensional) light distribution is spherically symmetric and has infinite gradient at its center, which is called spherical-nucleus solution and is used to model galaxy central area. We can make changes of the coordinate system by cutting out some column areas of its definition domain, the areas containing the galaxy center. The resulting spatial (3-dimensional) light distributions are axisymmetric or triaxial and have zero gradient at the center, which are called elliptical-shape solutions and are used to model global elliptical patterns. The two types of logarithmic light distributions are added together to model full elliptical galaxy patterns. The model is a generalization of the Dehnen model. One of the elliptical-shape solutions permits realistic numerical calculation and is fitted to all R-band elliptical images from Frei et al. (Astron. J. 111:174, 1996) galaxy sample. The fitting is satisfactory. This suggests that elliptical galaxy patterns can be represented in terms of a few basic parameters.
Optimal Allocation of Resources in Airport Security: Profiling vs. Screening

This model examines the role of intelligence gathering and screening in providing airport security. We analyze this problem using a game between the government and a terrorist. By investing in intelligence gathering, the government can improve the precision of its information. In contrast, screening can be used to search a passenger and thereby deter terrorist attacks. We determine the optimal allocation of resources between these two strategies wherein we model the role of intelligence using the concept of supermodular precision. One striking result is that under certain circumstances, an increase in the investment in intelligence can induce a more devious terrorist to attack with a higher probability. We also find that when there is a cost-reducing innovation in the screening technology, then the optimal investment in intelligence gathering can go either way. However, such an innovation unambiguously improves social welfare. Another interesting implication is that a developed economy would value intelligence inputs more than a developing economy. We also examine the efficacy of a program such as PreCheck that allows some select passengers expedited screening in exchange for voluntarily revealing information about themselves. Our analysis shows that such a program can be used to cushion the adverse effect of budgetary shortages. Finally, we also examine the role of enhanced punishment on the optimal level of intelligence. We find that the result can go both ways. If the initial level of punishment is high, then any further enhancement reduces the optimal level of intelligence gathering. However, this result is reversed if the initial level of punishment is low.
New Pathways to Heteroepitaxial GaN by Inorganic CVD Synthesis and Characterization of Related Ga-C-N Novel Systems

The authors describe the development of a new deposition method for thin oriented films of GaN on basal plane sapphire using an exclusively inorganic single-source precursor free of carbon and hydrogen, Cl{sub 2}GaN{sub 3}. The films have been characterized by Rutherford backscattering spectroscopy (RBS) and cross sectional transmission electron microscopy (TEM) for composition morphology and structure. RBS analysis confirmed stoichiometric GaN and TEM observations of the highly conformal films revealed heteroepitaxial columnar growth of crystalline wurtzite material on sapphire. Auger and RBS oxygen and carbon resonance profiles indicated that the films were pure and highly homogeneous. They also report the reactions of Cl{sub 2}GaN{sub 3} with organometallic nitrides to yield a crystalline, novel gallium carbon nitride of composition GaC{sub 3}N{sub 3}. Quantitative X-ray powder diffraction has been used to refine the cubic structure of this material which consists of Ga atoms octahedrally surrounded by on the average three C and three N atoms. The structurally analogous LiGaC{sub 4}N{sub 4} phase has also been prepared and characterized.
The stability of sustained oscillations in symmetric cooperative-competitive networks

Abstract Cohen and Grossberg (1983) proved that a large class of neural networks can function as stable content addressable memories. These Cohen-Grossberg networks were designed to include additive neural networks as studied by Hopfield (1984), and shunting neural networks. The shunting networks included cooperative-competitive networks, also called on-center off-surround feedback networks. The coefficients of the negative feedback signals between populations were drawn from a symmetric matrix. The positive feedback signals were self-excitatory only; that is, no node took excitation from any of its neighbors. The question was next raised concerning how much the Cohen-Grossberg form for a content addressable memory could be generalized. Cohen (1988) showed that if the excitatory on-center was broadened to admit positive feedback from neighboring populations, then persistent oscillations were possible. In this work, the stability of some of these oscillations is shown by studying the Hopf bifurcation constructed in Cohen (1988). These neural networks are transformed to a standard coordinate system and the computation of a coefficient which determines the stability of the oscillations near the Hopf bifurcation is carried out. The negativity of this coefficient implies the bifurcating periodic orbits are stable.
Dust in cosmic plasma environments

Cosmic dust is invariably immersed in a plasma and a radiative environment. Consequently, it is charged to some electrostatic potential which depends on the properties of the environment as well as the nature of the dust. This charging affects the physical and dynamical properties of the dust. In this paper the basic aspects of this dust-plasma interaction in several cosmic environments — including planetary magnetospheres, the heliosphere and the interstellar medium — are discussed. The physical and dynamical consequences of the interaction, as well as the pertinent observational evidence, are reviewed. Finally, the importance of the surface charge during the condensation process in plasma environments is stressed.
Mixing Time of the Rudvalis Shuffle

We extend a technique for lower-bounding the mixing time of card-shuffling Markov chains, and use it to bound the mixing time of the Rudvalis Markov chain, as well as two variants considered by Diaconis and Saloff-Coste. We show that in each case $\Theta(n^3 \log n)$ shuffles are required for the permutation to randomize, which matches (up to constants) previously known upper bounds. In contrast, for the two variants, the mixing time of an individual card is only $\Theta(n^2)$ shuffles.
Adaptive tomographic sensors for below ground imaging

Herein, ground penetrating radar and tomography are combined to detect and identify hidden targets, such as underground facilities and bard and deeply buried targets. Past experiences in below-ground imaging is described, current measurement results are presented, and future plans are discussed.
A valuation criterion for normal basis generators in local fields of characteristic p

Let K be a complete local field of characteristic p with perfect residue field, and let L/K be a finite, totally ramified, Galois p-extension with G = Gal(L/K). Let v L be the normalized valuation with $${v_L(L^{\times})=\mathbb{Z} }$$ . Let $${\pi_L\in L}$$ be a prime element, and let p′ (x) be the derivative of the minimal polynomial for π L over K. We show that any element $${\rho\in L}$$ with $${v_L(\rho)\equiv -v_L(p'(\pi_L))-1\bmod[L:K]}$$ generates a normal basis: K[G]ρ = L. This criterion is tight: Given any integer i with $${i\not\equiv -v_L(p'(\pi_L))-1\bmod[L:K]}$$ , there is a $${\rho_i\in L}$$ with v L (ρ i ) = i such that $${K[G]\rho_i\subsetneq L}$$ .
THE X-RAY PROPERTIES OF THE OPTICALLY BRIGHTEST MINI-BAL QUASARS FROM THE SLOAN DIGITAL SKY SURVEY

This article compiles a sample of 14 of the optically brightest radio-quiet quasars in the Sloan Digital Sky Survey Data Release 5 quasar catalog that have mini-broad absorption lines present in their spectra.
A Probabilistic Collocation Method Based Statistical Gate Delay Model Considering Process Variations and Multiple Input Switching

Since the advent of new nanotechnologies, the variability of gate delay due to process variations has become a major concern. This paper proposes a new gate delay model that includes impact from both process variations and multiple input switching. The proposed model uses an orthogonal polynomial based probabilistic collocation method to construct a delay analytical equation from circuit timing performance. From the experimental results, our approach has less that 0.2% error on the mean delay of gates and less than 3% error on the standard deviation.
UNKNOTTING VIRTUAL KNOTS WITH GAUSS DIAGRAM FORBIDDEN MOVES

The forbidden moves can be combined with Gauss diagram Reidemeister moves to obtain move sequences with which we may change any Gauss diagram (and hence any virtual knot) into any other, including in particular the unknotted diagram.
Logarithmic Lipschitz norms and diffusion-induced instability

Abstract This paper proves that ordinary differential equation systems that are contractive with respect to L p norms remain so when diffusion is added. Thus, diffusive instabilities, in the sense of the Turing phenomenon, cannot arise for such systems, and in fact any two solutions converge exponentially to each other. The key tools are semi inner products and logarithmic Lipschitz constants in Banach spaces. An example from biochemistry is discussed, which shows the necessity of considering non-Hilbert spaces. An analogous result for graph-defined interconnections of systems defined by ordinary differential equations is given as well.
Network-Guided Sparse Learning for Predicting Cognitive Outcomes from MRI Measures

Alzheimer's disease (AD) is characterized by gradual neurodegeneration and loss of brain function, especially for memory during early stages. Regression analysis has been widely applied to AD research to relate clinical and biomarker data such as predicting cognitive outcomes from MRI measures. In particular, sparse models have been proposed to identify the optimal imaging markers with high prediction power. However, the complex relationship among imaging markers are often overlooked or simplified in the existing methods. To address this issue, we present a new sparse learning method by introducing a novel network term to more flexibly model the relationship among imaging markers. The proposed algorithm is applied to the ADNI study for predicting cognitive outcomes using MRI scans. The effectiveness of our method is demonstrated by its improved prediction performance over several state-of-the-art competing methods and accurate identification of cognition-relevant imaging markers that are biologically meaningful.
Poisson Cohomology of SU(2)-Covariant "Necklace" Poisson Structures on S 2

Abstract We compute the Poisson cohomology of the one-parameter family of SU(2)-covariant Poisson structures on the homogeneous space S 2=ℂP 1=SU(2)/U(1), where SU(2) is endowed with its standard Poisson–Lie group structure, thus extending the result of Ginzburg [2] on the Bruhat–Poisson structure which is a member of this family. In particular, we compute several invariants of these structures, such as the modular class and the Liouville class. As a corollary of our computation, we deduce that these structures are nontrivial deformations of each other in the direction of the standard rotation-invariant symplectic structure on S 2; another corollary is that these structures do not admit smooth rescaling.
Bargaining in the Shadow of the Law: Divorce Laws and Family Distress

Over the past thirty years changes in divorce law have significantly increased access to divorce. The different timing of divorce law reform across states provides a useful quasi-experiment with which to examine the effects of this change. We analyze state panel data to estimate changes in suicide, domestic violence, and spousal murder rates arising from the change in divorce law. Suicide rates are used as a quantifiable measure of wellbeing, albeit one that focuses on the extreme lower tail of the distribution. We find a large, statistically significant, and econometrically robust decline in the number of women committing suicide following the introduction of unilateral divorce. No significant effect is found for men. Domestic violence is analyzed using data on both family conflict resolution and intimate homicide rates. The results indicate a large decline in domestic violence for both men and women in states that adopted unilateral divorce. We find suggestive evidence that unilateral divorce led to a decline in females murdered by their partners, while the data revealed no discernible effects for men murdered. In sum, we find strong evidence that legal institutions have profound real effects on outcomes within families.
Experiments in Teleoperator and Autonomous Control of Space Robotic Vehicles

This paper presents a program of research embracing teleoperator and automatic navigational control of freely-flying satellite robots. Current research goals include developing visual operator interfaces for improved vehicle teleoperation; determining the effects of different visual interface system designs on operator performance; and achieving autonomous, vision-based vehicle navigation and control. This research program combines virtual-environment teleoperation studies and neutral-buoyancy experiments using a space robot simulator vehicle currently under development. Visual-interface design options under investigation will include monoscopic versus stereoscopic displays and cameras, helmet-mounted versus panel-mounted display monitors, head-tracking versus fixed or manually steerable remote cameras, and provision of vehicle-fixed visual cues, or markers, in the remote scene for improved sensing of vehicle position, orientation, and motion. Autonomous-control research currently focuses on the development of the neutral-buoyancy vehicle and vision-based sensing systems required to support future automatic vehicle control experiments.
An assessment study of the wavelet-based index of magnetic storm activity (WISA) and its comparison to the Dst index

Abstract A wavelet-based index of storm activity (WISA) has been recently developed [Jach, A., Kokoszka, P., Sojka, L., Zhu, L., 2006. Wavelet-based index of magnetic storm activity. Journal of Geophysical Research 111, A09215, doi:10.1029/2006JA011635 ] to complement the traditional Dst index. The new index can be computed automatically by using the wavelet-based statistical procedure without human intervention on the selection of quiet days and the removal of secular variations. In addition, the WISA is flexible on data stretch and has a higher temporal resolution (1 min), which can provide a better description of the dynamical variations of magnetic storms. In this work, we perform a systematic assessment study on the WISA index. First, we statistically compare the WISA to the Dst for various quiet and disturbed periods and analyze the differences of their spectral features. Then we quantitatively assess the flexibility of the WISA on data stretch and study the effects of varying number of stations on the index. In addition, the ability of the WISA for handling the missing data is also quantitatively assessed. The assessment results show that the hourly averaged WISA index can describe storm activities equally well as the Dst index, but its full automation, high flexibility on data stretch, easiness of using the data from varying number of stations, high temporal resolution, and high tolerance to missing data from individual station can be very valuable and essential for real-time monitoring of the dynamical variations of magnetic storm activities and space weather applications, thus significantly complementing the existing Dst index.
Grader Bias in Cattle Markets? Evidence from Iowa

Live cattle are increasingly priced as an explicit function of U.S. Department of Agriculture yield and quality grades. Human graders visually inspect each slaughtered carcass and call grades in a matter of seconds as the carcass passes on a moving trolley. We examine whether there is systematic bias in grade calls using a sample of loads delivered to three different midwestern packing plants during 2000‐2002. Overall, results indicate that indeed there is a bias, and that grading standards vary significantly across packing plants. Results also are consistent with a behavioral model where graders are more accurate when grading relatively low-quality carcasses.
New clues to the impact broadening mystery in radio recombination lines

Problems where impact broadened radio recombination lines appeared narrower than predicted first showed up ∼40 years ago at frequencies below ∼3 GHz. But it was soon found that the observations could be explained by throwing out the uniform density models and replacing them with variable density ones. However, this problem re-appeared recently when a mysterious line narrowing above quantum numbers of (n,Δn)=(202,8) was reported from sensitive observations of Orion and W51 near 6 GHz. Here it is demonstrated that the narrowing is unlikely to be caused by the data processing technique and therefore must be source related. It is further demonstrated that the observed line narrowing can be tied to one of the fundamental properties of radio recombination lines; namely the fact that the spacing of adjacent n-transitions increases with frequency. The line narrowing is observed to begin when the n-transition density, D n , exceeds ∼11.6 transitions per GHz. This may imply that it is somehow related either to a previously overlooked effect in the impact broadening process, or to some unknown parallel process, that is tied to the separation between adjacent n-transitions. Based on these results it can be concluded, as has also been concluded in several theoretical investigations, that the observed line narrowing is not tied to a fixed range of either n or Δn.