cssi/SciSciGPT-SciSciNet huggingface dataset:
Measurement of the lunar neutron density profile

Anin situ measurement of the lunar neutron density from 20 to 400 g cm−2 depth below the lunar surface was made by the Apollo 17 Lunar Neutron Probe Experiment (LNPE) using particle tracks produced by the10B (n,α)7Li reaction. Both the absolute magnitude and the depth profile of the neutron density are in good agreement with theoretical calculations by Lingenfelter, Canfield, and Hampel. However, relatively small deviations between experiment and theory in the effect of Cd absorption on the neutron density and in the relative149Sm to157Gd capture rates reported previously (Russet al., 1972) imply that the true lunar157Gd capture rate is about one half of that calculated theoretically.
From 'not wrong' to (maybe right).

This is a short, light spirited account of how some possibly important science actually happened. It very much conflicts with Popper's contention that the key to scientific progress is falsification.
Simple analytical models for the temperature dependent threshold behavior of depletion-mode devices

Threshold voltage shifts in ion-implanted depletion-mode MOSFET's depart substantially from the usual dose proportional shift of enhancement-mode devices. Analytic expressions for the relationship between threshold voltage shift and implanted donor dose and position are extended to include impurity freezeout at low temperatures, and a simple model for the observed low substrate sensitivity at low temperature is presented. Criteria to avoid parasitic subthreshold conduction in depletion-mode devices are also established using the threshold shift formulation.
Orbital debris impact damage to reusable launch vehicles

Summary In an effort by the National Aeronautics and Space Administration (NASA), hypervelocity impact tests were performed on thermal protection systems (TPS) applied on the external surfaces of reusable launch vehicles (RLV) to determine the potential damage from orbital debris impacts. Three TPS types were tested, bonded to composite structures representing RLV fuel tank walls. The three heat shield materials tested were Alumina-Enhanced Thermal Barrier-12 (AETB-12), Flexible Reusable Surface Insulation (FRSI), and Advanced Flexible Reusable Surface Insulation (AFRSI). Using this test data, predictor equations were developed for the entry hole diameters in the three TPS materials, with correlation coefficients ranging from 0.69 to 0.86. Possible methods are proposed for approximating damage occurring at expected orbital impact velocities higher than tested, with references to other published work.
Intergalactic Dust and Observations of Type Ia Supernovae

Estimates of the cosmic star formation rate and of cluster metallicities independently imply that at z 0.5 the gas in the universe has substantial average metallicity: 1/10 Z/Z☉ 1/3 for Ωgas = 0.05. This metal density probably cannot be contained in known solar-metallicity galaxies of density parameter Ω* ≈ 0.004, implying significant enrichment of the intergalactic medium (IGM) by ejection of metals and dust from galaxies via winds, in mergers or in dust efflux driven by radiation pressure. Galaxies have a dust-to-metal ratio of ~0.5 in their interstellar media, but some fraction (1 - f) > 0 of this must be destroyed in the IGM or during the ejection process. Assuming the Draine & Lee dust model and preferential destruction of small grains (as destruction by sputtering would provide), I calculate the reddening and extinction of a uniform cosmological dust component in terms of f and the minimum grain size amin. Very small grains provide most of the reddening but less than half of the opacity for optical extinction. For f 0.3 and amin 0.1 μm, the intergalactic dust would be too gray to have been detected by its reddening, yet dense enough to be cosmologically important: it could account for the recently observed Type Ia supernova dimming at z ~ 0.5 without cosmic acceleration. It would also have implications for galaxy counts and evolutionary studies and would contribute significantly to the cosmic infrared background (CIB). The importance of gray intergalactic dust of the described type can be tested by observations of z = 0.5 supernovae in (rest) R-band or longer wavelengths and by the fluxes of a large sample of supernovae at z > 1.
Effective field theory and nuclear mean-field models

The implications of an effective field theory (EFT) interpretation of nuclear mean-field phenomenology are reviewed.
Solution-phase synthesis of a combinatorial monocyclic β-lactam library: Potential protease inhibitors

Abstract A 126-member library of monocyclic β-lactams was generated in parallel fashion by solution-phase Ugi four-component condensation reaction between β-amino acids, aldehydes, and isocyanides. The library was designed to identify potential human leukocyte elastase inhibitors. The approach is also capable of optimizing the lead compounds generated in the original library.
Pair correlation of the zeros of the Riemann zeta function in longer ranges

In this paper, we study a more general pair correlation function, $F_h(x,T)$, of the zeros of the Riemann zeta function. It provides information on the distribution of larger differences between the zeros.
Aeroshell Design Techniques for Aerocapture Entry Vehicles

Abstract A major goal of NASA's In-Space Propulsion Program is to shorten trip times for scientific planetary missions. To meet this challenge arrival speeds will increase, requiring significant braking for orbit insertion, and thus increased deceleration propellant mass that may exceed launch lift capabilities. A technology called aerocapture has been developed to expand the mission potential of exploratory probes destined for planets with suitable atmospheres. Aerocapture inserts a probe into planetary orbit via a single pass through the atmosphere using the probe's aeroshell drag to reduce velocity. The benefit of an aerocapture maneuver is a large reduction in propellant mass that may result in smaller, less costly missions and reduced mission cruise times. The methodology used to design rigid aerocapture aeroshells will be presented with an emphasis on a new systems tool under development. Current methods for fast, efficient evaluations of structural systems for exploratory vehicles to planets and moons within our solar system have been under development within NASA having limited success. Many systems tools that have been attempted applied structural mass estimation techniques based on historical data and curve fitting techniques that are difficult and cumbersome to apply to new vehicle concepts and missions. The resulting vehicle aeroshell mass may be incorrectly estimated or have high margins included to account for uncertainty. This new tool will reduce the guesswork previously found in conceptual aeroshell mass estimations.
Exact sparse recovery with L0 projections

Many applications (e.g., anomaly detection) concern sparse signals. This paper focuses on the problem of recovering a K-sparse signal x ∈ R/1×N, i.e., K N and ∑N/i=1 1{xi ≠ 0} = K. In the mainstream framework of compressed sensing (CS), × is recovered from M linear measurements y = xS ∈ R/1×M, where S ∈ RN×M is often a Gaussian (or Gaussian-like) design matrix. In our proposed method, the design matrix S is generated from an α-stable distribution with α ≈ 0. Our decoding algorithm mainly requires one linear scan of the coordinates, followed by a few iterations on a small number of coordinates which are "undetermined" in the previous iteration. Our practical algorithm consists of two estimators. In the first iteration, the (absolute) minimum estimator is able to filter out a majority of the zero coordinates. The gap estimator, which is applied in each iteration, can accurately recover the magnitudes of the nonzero coordinates. Comparisons with linear programming (LP) and orthogonal matching pursuit (OMP) demonstrate that our algorithm can be significantly faster in decoding speed and more accurate in recovery quality, for the task of exact spare recovery. Our procedure is robust against measurement noise. Even when there are no sufficient measurements, our algorithm can still reliably recover a significant portion of the nonzero coordinates.
Dimension groups for interval maps II: the transitive case

Any continuous, transitive, piecewise monotonic map is determined up to a binary choice by its dimension module with the associated finite sequence of generators. The dimension module by itself determines the topological entropy of any transitive piecewise monotonic map, and determines any transitive unimodal map up to conjugacy. For a transitive piecewise monotonic map which is not essentially injective, the associated dimension group is a direct sum of simple dimension groups, each with a unique state.
Correlated continuous time random walks

Continuous time random walks impose a random waiting time before each particle jump. Scaling limits of heavy-tailed continuous time random walks are governed by fractional evolution equations. Space-fractional derivatives describe heavy-tailed jumps, and the time-fractional version codes heavy-tailed waiting times. This paper develops scaling limits and governing equations in the case of correlated jumps. For long-range dependent jumps, this leads to fractional Brownian motion or linear fractional stable motion, with the time parameter replaced by an inverse stable subordinator in the case of heavy-tailed waiting times. These scaling limits provide an interesting class of non-Markovian, non-Gaussian self-similar processes.
Persistent phylogeny: a galled-tree and integer linear programming approach

The Persistent-Phylogeny Model is an extension of the widely studied Perfect-Phylogeny Model, encompassing a broader range of evolutionary phenomena. Biological and algorithmic questions concerning persistent phylogeny have been intensely investigated in recent years. In this paper, we explore two alternative approaches to the persistent-phylogeny problem that grow out of our previous work on perfect phylogeny, and on galled trees. We develop an integer programming solution to the Persistent-Phylogeny Problem; empirically explore its efficiency; and empirically explore the utility of using fast algorithms that recognize galled trees, to recognize persistent phylogeny. The empirical results identify parameter ranges where persistent phylogeny are galled trees with high frequency, and show that the integer programming approach can efficiently identify persistent phylogeny of much larger size than has been previously reported.
Maximum Principles for Null Hypersurfaces and Null Splitting Theorems

A maximum principle for C^0 null hypersurfaces is obtained and used to derive a splitting theorem for spacetimes which contain null lines. As a consequence of this null splitting theorem, it is proved that an asymptotically simple vacuum (Ricci flat) spacetime which contains a null line is isometric to Minkowski space.
Formal [4 + 2] Cycloaddition of Donor−Acceptor Cyclobutanes and Aldehydes: Stereoselective Access to Substituted Tetrahydropyrans

A highly diastereoselective synthesis of 2,6-cis-disubstituted tetrahydropyrans (THPs) via Lewis acid-catalyzed formal [4 + 2] cycloaddition of donor−acceptor cyclobutanes and aldehydes has been developed. THP products are formed in up to 96% yield and 99:1 diastereoselectivity. Aromatic, cinnamyl, and aliphatic aldehydes are competent dipolarophiles in this system. This methodology was extended to a [[2 + 2] + 2] cycloaddition of 4-methoxystyrene, dimethyl methylidene malonate, and an aldehyde to furnish THPs directly without prior isolation of the cyclobutane.
Behavioral issues in the use of interactive systems

This paper identifies behavioral issues related to the use of interactive computersprimarily by persons who are not computer professionals, so-called “general users”. This is not an exhaustive literature survey but instead provides: (1) a structure fordiscussing issues of interactive computing, and (2) the authors' best estimate of important behavioral problems, with suggestions for solutions. The discussion is limited in this paper to general issues which do not take into account the user's particular task. The two major topics are System Characteristics (performance, facilities and on-line information), and Interface Characteristics (dialogue style, displays and graphics, other input/output media).
Duality Questions for Operators, Spectrum and Measures

We explore spectral duality in the context of measures in ℝ n , starting with partial differential operators and Fuglede’s question (1974) about the relationship between orthogonal bases of complex exponentials in L 2(Ω) and tiling properties of Ω, then continuing with affine iterated function systems. We review results in the literature from 1974 up to the present, and we relate them to a general framework for spectral duality for pairs of Borel measures in ℝ n , formulated first by Jorgensen and Pedersen.
Spectra of measures and wandering vectors

We present a characterization of the sets that appear as Fourier spectra of measures in terms of the existence of a strongly continuous representation of the ambient group that has a wandering vector for the given set.
Stacking the deck: the effects of top management backgrounds on investor decisions

Young firms going public are dependent upon the decisions of investors for a successful public offering. Yet convincing investors to invest is not easy, as young firms have limited track records and, thus, face challenges associated with gaining legitimacy in their respective industries. This paper examines ways in which select information about firms undertaking an initial public offering (IPO) can affect investor decisions. Building upon recent research on upper echelons and signaling theory, we propose that the composition of a firm's top management team can signal organizational legitimacy that in turn affects investor decisions. In the context of young firms undertaking an IPO, such signals are critical, especially when objective measures of firm quality are not easily available. We introduce a typology of signals of organizational legitimacy to elaborate on our hypotheses. Analyses of a comprehensive set of data on the career histories of the top management teams of young biotechnology firms show that investor decisions are affected by the extent to which a firm's top management team has employment affiliations with prominent downstream organizations (e.g., pharmaceutical companies), with a diverse range of organizations, and upon the role experience of one key member of the top management team—the Chief Scientific Officer. We assess and find that these effects are not mediated by the prestige of a firm's lead underwriter. We conclude with a discussion of the implications of our study for strategy research on upper echelons and organizational legitimacy. Copyright © 2006 John Wiley & Sons, Ltd.
The “Levels of Experience” Doctrine in Modern Philosophy of Mind

A knowledgeable yet impartial observer who was able to view contemporary philosophy from some vantage point in space might understandably conclude that there appeared to be little if anything common to the various movements of thought. Not only would the visible structures appear of different architectural design, much as the houses in different sections of a town, but even the usually hidden foundations would appear composed of different materials. He might easily be tempted to conclude in opposition to an earlier observer, that "... the dissonant is not in harmony with itself, the contraries are mutually exclusive." However, just as the foundations of houses in different sections of a town can at times rest on some common geological bedrock, so does contemporary philosophy share a common substratum. I am going to argue that the "levels of experience" doctrine is not only central to much of recent philosophical thought but also that it has received remarkably similar interpretation by philosophers of quite different movements.
Mitigating timing side channel in shared schedulers

In this work, we study information leakage in timing side channels that arise in the context of shared event schedulers. Consider two processes, one of them an innocuous process (referred to as Alice) and the other a malicious one (referred to as Bob), using a common scheduler to process their jobs. There are other innocuous users in addition to Alice and Bob using the scheduler to process their jobs. Based on when his jobs get processed, Bob wishes to learn about the pattern (size and timing) of Alice's jobs. Depending on the context, knowledge of this pattern could have serious implications on Alice's privacy and security. For instance, shared routers can reveal traffic patterns, shared memory access can reveal cloud usage patterns, and suchlike. We present a formal framework to study the information leakage in shared resource schedulers using the pattern estimation error as a performance metric. The first-come-first-serve (FCFS) scheduling policy and time-division-multiple-access (TDMA) are identified as two extreme policies on the privacy metric, FCFS has the least, and TDMA has the highest. However, on performance-based metrics, such as throughput and delay, it is well known that FCFS significantly outperforms TDMA. We then derive two parameterized policies, accumulate and serve, and proportional TDMA, which take two different approaches to offer a tunable trade-off between privacy and performance.
Exceptional groups from open strings

Abstract We consider type IIB theory compactified on a two-sphere in the presence of mutually non-local 7-branes. The BPS states associated with the gauge vectors of exceptional groups are seen to arise from open strings connecting the 7-branes, and multi-pronged open strings capable of ending on more than two 7-branes. These multi-pronged strings are built from open string junctions that arise naturally when strings cross 7-branes. The different string configurations can be multiplied as traditional open strings, and are shown to generate the structure of exceptional groups.
Simulation and Flight Test Evaluation of Head-Up-Display Guidance for Harrier Approach Transitions

Position and speed guidance displays for STOVL aircraft curved, decelerating approaches to hover and vertical landing have been evaluated for their effectiveness in reducing pilot workload and improving performance. The NASA V/STOL Systems Research Aircraft, a modified YAV-8B Harrier prototype, was used to evaluate the displays in flight, whereas the NASA Ames Vertical Motion Simulator was used to extend the flight test results to instrument meteorological conditions (IMC) and to examine performance in various conditions of wind and turbulence. The simulation data showed close correlation with the flight test data, and both demonstrated the feasibility of the displays. With the exception of the hover task in zero visibility, which was level-3, averaged Copper-Harper handling qualities ratings given during simulation were level-2 for both the approach task and the hover task in all conditions. During flight tests in calm and clear conditions, the displays also gave rise to level-2 handling qualities ratings. Pilot opinion showed that the guidance displays would be useful in visual flight, especially at night, as well as in IMC.
The quantum euler class and the quantum cohomology of the Grassmannians

The Poincare duality of classical cohomology and the extension of this duality to quantum cohomology endows these rings with the structure of a Frobenius algebra. Any such algebra possesses a canonical “characteristic element;” in the classical case this is the Euler class, and in the quantum case this is a deformation of the classical Euler class which we call the “quantum Euler class.” We prove that the characteristic element of a Frobenius algebraA is a unit if and only ifA is semisimple, and then apply this result to the cases of the quantum cohomology of the finite complex Grassmannians, and to the quantum cohomology of hypersurfaces. In addition we show that, in the case of the Grassmannians, the [quantum] Euler class equals, as [quantum] cohomology element and up to sign, the determinant of the Hessian of the [quantum] Landau-Ginzbug potential.
Deep versus compiled knowledge approaches to diagnostic problem-solving

Most of the current generation expert systems use knowledge which does not represent a deep understanding of the domain, but is instead a collection of “pattern?action” rules, which correspond to the problem-solving heuristics of the expert in the domain. There has thus been some debate in the field about the need for and role of “deep” knowledge in the design of expert systems. It is often argued that this underlying deep knowledge will enable an expert system to solve hard problems. In this paper we consider diagnostic expert systems and argue that given a body of underlying knowledge that is relevant to diagnostic reasoning in a medical domain, it is possible to create a diagnostic problem-solving structure which has all the aspects of the underlying knowledge needed for diagnostic reasoning “compiled” into it. It is argued this compiled structure can solve all the diagnostic problems in its scope efficiently, without any need to access the underlying structures. We illustrate such a diagnostic structure by reference to our medical system MDX. We also analyze the use of these knowledge structures in providing explanations of diagnostic reasoning.
A Space-Time Adaptive Method for Simulating Complex Cardiac Dynamics

For plane-wave and many-spiral states of the experimentally based Luo-Rudy 1 model of heart tissue in large (8 cm square) domains, we show that a space-time-adaptive time-integration algorithm can achieve a factor of 5 reduction in computational effort and memory---but without a reduction in accuracy---when compared to an algorithm using a uniform space-time mesh at the finest resolution. Our results indicate that such an algorithm can be extended straightforwardly to simulate quantitatively three-dimensional electrical dynamics over the whole human heart.
Walks on SPR Neighborhoods

A nearest-neighbor-interchange (NNI)-walk is a sequence of unrooted phylogenetic trees, $(T_1, T_2, \ldots, T_k)$ where each consecutive pair of trees differs by a single NNI move. We give tight bounds on the length of the shortest NNI-walks that visit all trees in a subtree-prune-and-regraft (SPR) neighborhood of a given tree. For any unrooted, binary tree, $(T)$, on $(n)$ leaves, the shortest walk takes $(\Theta (n^2))$ additional steps more than the number of trees in the SPR neighborhood. This answers Bryant's Second Combinatorial Challenge from the Phylogenetics Challenges List, the Isaac Newton Institute, 2011, and the Penny Ante Problem List, 2009.
A numerical study of ignition in a premixed flame burner

Abstract This paper presents a random numerical method which combines a random vortex method and a random choice method. With the assumption of incompressibility, the equations governing the fluid motion can be uncoupled from the equations governing the chemical reaction. A hybrid random vortex method is used for solving the Navier-Stokes equation which governs the fluid motion. A combustion process is governed by the reaction-diffusion system for the conservation of energy and the various chemical species participating in reaction. A random choice method is used for modeling reaction-diffusion equations. The method is applied to an ignition of the Bunsen burner. Flame propagation profiles are obtained and have good agreement with experimental results.
Systemic financial distress and auction-based bankruptcy reorganization ☆

Abstract Most bankruptcy procedures try to reorganize a financially-distressed firm's debts to a serviceable level through negotiations overseen by courts. Markets are an alternative to such negotiations. This paper develops a market-based approach that is appropriate if claimants are severely cash-constrained and there is merit in having existing owners-managers remain in control. This approach was developed in response to the 1997 Asian Crisis, where the sheer numbers of over-indebted firms, creditors with poor incentives, and inexperienced courts stymied negotiated resolution. The scheme, however, can be applied to other crisis settings that exhibit particular characteristics. One such setting could be the resolution of external sovereign debts, a situation where creditors obviously cannot take possession of a country. The scheme arranges creditors in a queue to be serviced in sequence from the firm's operating cash flows. Creditors bid for their position in this queue, and those accepting a greater proportionate reduction in the face value of their claims are placed ahead of the others. Any existing hierarchy of claims is honored by having claimants bid for their positions within the relevant segment of the queue. No one in the queue (including owners who are last) is paid anything until the (reduced) debts of the first in line are fully discharged using the firm's operating cash surpluses. The queue then moves up and the next claimant in line is serviced. The paper shows that, in equilibrium, the aggregate debts of the firm are reduced enough to provide a positive expected residual return to the owner-managers, which improves their incentives to efficiently operate the firm and can result in an outcome that is Pareto superior to other bankruptcy procedures. We discuss the efficiency properties of this scheme and its appropriateness to situations of systemic financial distress.
Genetic control models with diffusion and delays

Abstract A compartmental model of genetic control by repression is examined. The model includes spatial diffusion in the compartment representing the cytoplasm and time delays for transcription and translation. A stability analysis is discussed for a range of diffusivities and cell radii. Numerical studies illustrate the analytical results and suggest a potential mechanism for the triggering of cell division based on the cell size.
Hierarchical Mobility Label Based Network: System model and performance analysis

Hierarchical Mobility Label Based Network (H-MLBN) is a new approach to the network layer mobility management problem that relies on MPLS-aware control plane and MPLS-based forwarding plane to provide IP mobility support for IPv4 and IPv6 mobile hosts and routers while being able to ensure optimal traffic delivery between the communicating devices. The hierarchical system is capable of both macro- and micro-mobility support without the use of Mobile IP and its derivatives thus eliminating the user and network facing performance penalties associated with triangular routing and bi-directional tunneling. This paper presents a system model and provides performance analysis for H-MLBN and compares its performance with the Mobile IP based schemes. The results indicate significant performance improvements in the forwarding plane traffic delivery as well as the control plane network update costs.
Price and quality competition under adverse selection: Market organization and efficiency

Firms compete with prices and qualities in markets where consumers have heterogeneous preferences and cost characteristics. Consumers demand two goods, which can be supplied jointly or separately by firms. We consider two strategy regimes for firms: uniform price-quality pairs, and screening price-quality menus. For each regime, we compare the equilibria under integration (each firm supplying both goods) and separation (each firm supplying one good). Integrating and separating markets change quality, efficiency, and welfare. The theory illustrates phenomena such as the carveout of mental health and substance abuse coverage from general health insurance, and creaming for low-cost students in locales with school choices. Copyright 2003 by the RAND Corporation.
NMOG Emissions Characterizations and Estimation for Vehicles Using Ethanol-Blended Fuels

Ethanol is a biofuel commonly used in gasoline blends to displace petroleum consumption; its utilization is on the rise in the United States, spurred by the biofuel utilization mandates put in place by the Energy Independence and Security Act of 2007 (EISA). The United States Environmental Protection Agency (EPA) has the statutory responsibility to implement the EISA mandates through the promulgation of the Renewable Fuel Standard. EPA has historically mandated an emissions certification fuel specification that calls for ethanol-free fuel, except for the certification of flex-fuel vehicles. However, since the U.S. gasoline marketplace is now virtually saturated with E10, some organizations have suggested that inclusion of ethanol in emissions certification fuels would be appropriate. The test methodologies and calculations contained in the Code of Federal Regulations for gasoline-fueled vehicles have been developed with the presumption that the certification fuel does not contain ethanol; thus, a number of technical issues would require resolution before such a change could be accomplished. This report makes use of the considerable data gathered during the mid-level blends testing program to investigate one such issue: estimation of non-methane organic gas (NMOG) emissions. The data reported in this paper were gathered from over 600 cold-start Federal Testmore » Procedure (FTP) tests conducted on 68 vehicles representing 21 models from model year 2000 to 2009. Most of the vehicles were certified to the Tier-2 emissions standard, but several older Tier-1 and national low emissions vehicle program (NLEV) vehicles were also included in the study. Exhaust speciation shows that ethanol, acetaldehyde, and formaldehyde dominate the oxygenated species emissions when ethanol is blended into the test fuel. A set of correlations were developed that are derived from the measured non-methane hydrocarbon (NMHC) emissions and the ethanol blend level in the fuel. These correlations were applied to the measured NMHC emissions from the mid-level ethanol blends testing program and the results compared against the measured NMOG emissions. The results show that the composite FTP NMOG emissions estimate has an error of 0.0015 g/mile {+-}0.0074 for 95% of the test results. Estimates for the individual phases of the FTP are also presented with similar error levels. A limited number of tests conducted using the LA92, US06, and highway fuel economy test cycles show that the FTP correlation also holds reasonably well for these cycles, though the error level relative to the measured NMOG value increases for NMOG emissions less than 0.010 g/mile.« less
A reliability-based optimization scheme for maintenance management in large-scale bridge networks

Incorporating network configurations in bridge management problems is computationally difficult. Because of the interdependencies among bridges in a network, they have to be analyzed together. Simulation-based numerical optimization techniques adopted in past research are limited to networks of moderate sizes. In this paper, a simple framework is developed to determine optimal maintenance plans for large networks with many bridges. The objective is to minimize disruption, specifically, the extra travel distance caused by potential bridge failures over a planning horizon and under a budget constraint. It is conjectured and then verified that the expected increase in vehicle-miles traveled due to failures can be approximated by the sum of expected increases due to individual failures. This allows the network-level problem to be decomposed into single-bridge problems and tackled efficiently. The computational effort increases linearly with the number of bridges.
Dissipative Dynamics in Semiconductors at Low Temperature

A mathematical model is introduced which describes the dissipation of electrons in lightly doped semi-conductors. The dissipation operator is proved to be densely defined and positive and to generate a Markov semigroup of operators. The spectrum of the dissipation operator is studied and it is shown that zero is a simple eigenvalue, which makes the equilibrium state unique. Also it is shown that there is a gap between zero and the rest of its spectrum which makes the return to equilibrium exponentially fast in time.
Cyclialkylations of conjugated dienones with furans

Abstract Fused tricyclic compounds with the salient features of the guaianolides and the pseudoguaianolides were prepared using a furan-based cyclialkylation strategy.
Interplay of relativistic and nonrelativistic transport in atomically precise segmented graphene nanoribbons

Graphene's isolation launched explorations of fundamental relativistic physics originating from the planar honeycomb lattice arrangement of the carbon atoms, and of potential technological applications in nanoscale electronics. Bottom-up fabricated atomically-precise segmented graphene nanoribbons, SGNRs, open avenues for studies of electrical transport, coherence, and interference effects in metallic, semiconducting, and mixed GNRs, with different edge terminations. Conceptual and practical understanding of electric transport through SGNRs is gained through nonequilibrium Green's function (NEGF) conductance calculations and a Dirac continuum model that absorbs the valence-to-conductance energy gaps as position-dependent masses, including topological-in-origin mass-barriers at the contacts between segments. The continuum model reproduces the NEGF results, including optical Dirac Fabry-Prot (FP) equidistant oscillations for massless relativistic carriers in metallic armchair SGNRs, and an unequally-spaced FP pattern for mixed armchair-zigzag SGNRs where carriers transit from a relativistic (armchair) to a nonrelativistic (zigzag) regime. This provides a unifying framework for analysis of coherent transport phenomena and interpretation of forthcoming experiments in SGNRs.
Student Curriculum Decisions

Grade 10 students at two high schools took the Case Development Questionnaire, an information-search assessment instrument. A description of the way these students sought to make curricular decisions was obtained: (1) they tended to select information which counselors had judged to be most relevant; (2) their information search sampled the available information areas with the exception of values, which tended to be neglected; (3) their information-search pattern changed as they received information, i.e., information at first considered important would be reclassified as unimportant (and vice versa) as new information was received; (4) the information area of abilities was considered the most important, plans and interests less important, and values least important.
REMARKS ON THE PHASE TRANSITION IN QCD

The significance of the question of the order of the phase transition in QCD, and recent evidence that real-world QCD is probably close to having a single second order transition as a function of temperature, is reviewed. Although this circumstance seems to remove the possibility that the QCD transition during the big bang might have had spectacular cosmological consequences, there is some good news: it allows highly non-trivial yet reliable quantitative predictions to be made for the behavior near the transition. These predictions can be tested in numerical simulations and perhaps even eventually in heavy ion collisions. The present paper is a very elementary discussion of the relevant concepts, meant to be an accessible introduction for those innocent of the renormalization group approach to critical phenomena and/or the details of QCD.
Amplification of magnetic fields by dynamo action in Gaussian-correlated helical turbulence

We investigate the growth and structure of magnetic fields amplified by kinematic dynamo action in turbulence with nonzero kinetic helicity. We assume a simple Gaussian velocity correlation tensor, which allows us to consider very large magnetic Reynolds numbers, up to 1012. We use the kinematic Kazantsev–Kraichnan model of dynamo and find a complete numerical solution for the correlation functions of growing magnetic fields.
Edgeworth equilibria in production economies

Abstract An Edgeworth equilibrium is an allocation that belongs to the core of every n -fold replica of the economy. In this work we study the properties of Edgeworth equilibria for economies with production and infinite-dimensional commodity spaces. Under some relatively mild conditions we establish (among other things) that (1) Edgeworth equilibria exist, (2) every Edgeworth equilibrium is a quasi-equilibrium, and (3) An allocation is an Edgeworth equilibrium if and only if it can be “decentralized” by a price system.
Exact bounds for degree centralization

Degree centralization is a simple and widely used index of degree distribution concentration in social networks. Conventionally, the centralization score is normalized by the maximum value attainable at the observed order; this results in a measure on the unit interval. Here, exact bounds are provided for degree centralization given density as well as order. It is shown that roughly half of the region of conceivable degree centralization scores is actually feasible, and that the geometry of the feasible region alters with graph size. Concentration of the distribution of graphs within the feasible region is shown, and a renormalized family of degree centralization indices which adjusts for both density and order is provided.
Soil-Landscape relationships at the lower reaches of a watershed at Bear Creek near Oak Ridge, Tennessee

The watersheds at Bear Creek, Oak Ridge, TN, have similar soil–landscape relationships. The lower reaches of many of these watersheds consist of headwater riparian wetlands situated between sloping non-wetland upland zones. The objectives of this study are to examine the effects of (i) slope and geomorphic processes, (ii) human impacts, and (iii) particular characteristics of soils and saprolite that may effect drainage and water movement in the wetlands and adjacent landscapes in one of these watersheds. A transect was run from west to east in a hydrological monitored area at the lower reaches of a watershed on Bear Creek. This transect extended from a steep side slope position across a floodplain, a terrace, and a shoulder slope. On the upland positions of the Nolichucky Shale, mass wasting, overland flow and soil creep currently inhibit soil formation on the steep side slope position where a Typic Dystrudept is present, while soil stability on the shoulder slope has resulted in the formation of a well-developed Typic Hapludult. In these soils, argillic horizons occur above C horizons on less sloping gradients in comparison to steeper slopes, which have Bw horizons over Cr (saprolite) material. A riparian wetland area occupies the floodplain section, where a Typic Endoaquept is characterized by poorly drained conditions that led to the development of redoximorphic features (mottling), gleying, organic matter accumulation, and minimal development of subsurface horizons. A thin colluvial deposit overlies a thick well developed Aquic Hapludalf that formed in alluvial sediments on the terrace position. The colluvial deposit from the adjacent shoulder slope is thought to result from soil creep and anthropogenic erosion caused by past cultivation practices. Runoff from the adjacent sloping landscape and groundwater from the adjacent wetland area perhaps contribute to the somewhat poorly drained conditions of this profile. Perched watertables occur in upland positions due to dense saprolite and clay plugging in the shallow zones of the saprolite. However, no redoximorphic features are observed in the soil on the side slope due to high runoff. Remnants of the underlying shale saprolite, which occur as small discolored zones resembling mottles, are also present. The soils in the study have a CEC of <10 cmol kg−1, silt loam textures and Fed values of 0.5–4.3%. These soils are also mainly acidic and low in total carbon.
A structural mechanism for calcium transporter headpiece closure.

To characterize the conformational dynamics of sarcoplasmic reticulum (SR) calcium pump (SERCA) we performed molecular dynamics simulations beginning with several different high-resolution structures. We quantified differences in structural disorder and dynamics for an open conformation of SERCA versus closed structures and observed that dynamic motions of SERCA cytoplasmic domains decreased with decreasing domain-domain separation distance. The results are useful for interpretation of recent intramolecular Forster resonance energy transfer (FRET) distance measurements obtained for SERCA fused to fluorescent protein tags. Those previous physical measurements revealed several discrete structural substates and suggested open conformations of SERCA are more dynamic than compact conformations. The present simulations support this hypothesis and provide additional details of SERCA molecular mechanisms. Specifically, all-atoms simulations revealed large-scale translational and rotational motions of the SERCA N-domain relative to the A- and P-domains during the transition from an open to a closed headpiece conformation over the course of a 400 ns trajectory. The open-to-closed structural transition was accompanied by a disorder-to-order transition mediated by an initial interaction of an N-domain loop (Nβ5-β6, residues 426-436) with residues 133-139 of the A-domain. Mutation of three negatively charged N-domain loop residues abolished the disorder-to-order transition and prevented the initial domain-domain interaction and subsequent closure of the cytoplasmic headpiece. Coarse-grained molecular dynamics simulations were in harmony with all-atoms simulations and physical measurements and revealed a close communication between fluorescent protein tags and the domain to which they were fused. The data indicate that previous intramolecular FRET distance measurements report SERCA structure changes with high fidelity and suggest a structural mechanism that facilitates the closure of the SERCA cytoplasmic headpiece.
The federated computer-aided control design system

ABSTRACT The structure and operation of the Federated Computer-Aided Control Design System is discussed. The system is termed “Federated” to indicate that it consists of several independently developed subsystems tied together by a unified data base. The objective is to provide the user with a unified system which spans the entire control design problem: modeling, design, and simulation. The paper discusses how the management of the data base is handled and the operation of an overall system supervisor. A set of supervisor commands are given which allow considerable flexibility to add subsystems and to tailor commands to the individual installation.
The Photoeccentric Effect and Proto-hot Jupiters. II. KOI-1474.01, a Candidate Eccentric Planet Perturbed by an Unseen Companion

The exoplanets known as hot Jupiters—Jupiter-sized planets with periods of less than 10 days—likely are relics of dynamical processes that shape all planetary system architectures. Socrates et al. argued that high eccentricity migration (HEM) mechanisms proposed for situating these close-in planets should produce an observable population of highly eccentric proto-hot Jupiters that have not yet tidally circularized. HEM should also create failed-hot Jupiters, with periapses just beyond the influence of fast circularization. Using the technique we previously presented for measuring eccentricities from photometry (the "photoeccentric effect"), we are distilling a collection of eccentric proto- and failed-hot Jupiters from the Kepler Objects of Interest (KOI). Here, we present the first, KOI-1474.01, which has a long orbital period (69.7340 days) and a large eccentricity e = 0.81^(+0.10)_(–0.07), skirting the proto-hot Jupiter boundary. Combining Kepler photometry, ground-based spectroscopy, and stellar evolution models, we characterize host KOI-1474 as a rapidly rotating F star. Statistical arguments reveal that the transiting candidate has a low false-positive probability of 3.1%. KOI-1474.01 also exhibits transit-timing variations of the order of an hour. We explore characteristics of the third-body perturber, which is possibly the "smoking-gun" cause of KOI-1474.01's large eccentricity. We use the host star's period, radius, and projected rotational velocity to measure the inclination of the stellar spin. Comparing KOI 1474.01's inclination, we find that its orbit is marginally consistent with being aligned with the stellar spin axis, although a reanalysis is warranted with future additional data. Finally, we discuss how the number and existence of proto-hot Jupiters will not only demonstrate that hot Jupiters migrate via HEM, but also shed light on the typical timescale for the mechanism.
Considerations in optimizing CMB polarization experiments to constrain inflationary physics

We quantify the limiting factors in optimizing current-technology cosmic microwave background (CMB) polarization experiments to learn about inflationary physics. We consider space-based, balloon-borne and ground-based experiments. We find that foreground contamination and residuals from foreground subtraction are ultimately the limiting factors in detecting a primordial gravity wave signal. For full-sky space-based experiments, these factors hinder the detection of tensor-to-scalar ratios of r 3 σ) tensor component in a realistic CMB experiment, inflation must either involve large field variations, or multi-field/hybrid models. Hybrid models can be easily distinguished from large field models due to their blue scalar spectral index. Therefore, an observation of a tensor/scalar ratio and n < 1 in future experiments with the characteristics considered here may be an indication that inflation is being driven by some physics in which the inflaton cannot be described as a fundamental field.
Impact of x-ray dose on the response of CR-39 to 1–5.5 MeV alphas

The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-Kα and Kβ x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula.
A stochastic Lagrangian proof of global existence of the Navier–Stokes equations for flows with small Reynolds number

Abstract We consider the incompressible Navier–Stokes equations with spatially periodic boundary conditions. If the Reynolds number is small enough we provide an elementary short proof of the existence of global in time Holder continuous solutions. Our proof uses a stochastic representation formula to obtain a decay estimate for heat flows in Holder spaces, and a stochastic Lagrangian formulation of the Navier–Stokes equations.
Electrical modelling of ion-damaged GaAs Schottky barrier interfaces

Electrical measurements and related computer modelling have been carried out for Al-GaAs Schottky diodes fabricated on ion-etched GaAs surfaces. Diode changes are seen at all ion energies, with a salient feature being reduction or total loss of the EL2-DLTS peak. A chemical etch before Schottky metal deposition results in diode parameter and EL2-DLTS recovery after about 100 and 1000A removal for 0.5 and 3 keV ion energies, respectively. The resulting equivalent circuit consists of lumped R and C components which represent the diode space-charge, a damaged, partly amorphous top layer, and bulk damage. Computer generated DLTS spectra and low frequency dispersion agree with experimental results.