cssi/SciSciGPT-SciSciNet huggingface dataset:
Fourier-Domain Multichannel Autofocus for Synthetic Aperture Radar

Synthetic aperture radar (SAR) imaging suffers from image focus degradation in the presence of phase errors in the received signal due to unknown platform motion or signal propagation delays. We present a new autofocus algorithm, termed Fourier-domain multichannel autofocus (FMCA), that is derived under a linear algebraic framework, allowing the SAR image to be focused in a noniterative fashion. Motivated by the mutichannel autofocus (MCA) approach, the proposed autofocus algorithm invokes the assumption of a low-return region, which generally is provided within the antenna sidelobes. Unlike MCA, FMCA works with the collected polar Fourier data directly and is capable of accommodating wide-angle monostatic SAR and bistatic SAR scenarios. Most previous SAR autofocus algorithms rely on the prior assumption that radar's range of look angles is small so that the phase errors can be modeled as varying along only one dimension in the collected Fourier data. And, in some cases, implicit assumptions are made regarding the SAR scene. Performance of such autofocus algorithms degrades if the assumptions are not satisfied. The proposed algorithm has the advantage that it does not require prior assumptions about the range of look angles, nor characteristics of the scene.
On the possibility of large axion decay constants

The decay constant of the QCD axion is required by observation to be small compared with the Planck scale. In theories of `natural inflation' and certain proposed anthropic solutions of the cosmological constant problem it would be interesting to obtain a large decay constant for axion-like fields from microscopic physics. String theory is the only context in which one can sensibly address this question. Here we survey a number of periodic fields in string theory in a variety of string vacua. In some examples, the decay constant can be parametrically larger than the Planck scale but the effective action then contains appreciable harmonics of order fA/Mp. As a result, these fields are no better inflaton candidates than Planck scale axions.
Polarization from magnetized accretion discs - II. The effects of absorption opacity on Faraday rotation

Equipartition magnetic fields can dramatically affect the polarization of radiation emerging from accretion disc atmospheres in active galactic nuclei. We extend our previous work on this subject by exploring the interaction between Faraday rotation and absorption opacity in local, plane-parallel atmospheres with parameters appropriate for accretion discs. Faraday rotation in pure scattering atmospheres acts to depolarize the radiation field by rotating the polarization planes of photons after last scattering. Absorption opacity in an unmagnetized atmosphere can increase or decrease the polarization compared to the pure scattering case, depending on the thermal source function gradient. Combining both Faraday rotation and absorption opacity, we find the following results. If absorption opacity is much larger than scattering opacity throughout the atmosphere, then Faraday rotation generally has only a small effect on the emerging polarization because of the small electron column density along a photon mean free path. However, if the absorption opacity is not too large and it acts alone to increase the polarization, then the effects of Faraday rotation can be enhanced over those in a pure scattering atmosphere. Finally, while Faraday rotation often depolarizes the radiation field, it can in some cases increase the polarization when the thermal source function does not rise too steeply with optical depth. We confirm the correctness of the analytic calculation by Silant'ev of the high magnetic field limit of the pure scattering atmosphere, which we incorrectly disputed in our previous paper.
O(N) universality and the chiral phase transition in QCD

We discuss universal scaling properties of (2+1)-flavor QCD in the vicinity of the chiral phase transition at vanishing as well as non-vanishing light quark chemical potential (mu(l)). We provide evidence for O(N) scaling of the chiral order parameter in (2+1)-flavor QCD and show that the scaling analysis of its derivative with respect to the light quark chemical potential provides a unique approach to the determination of the curvature of the chiral phase transition line in the vicinity of mu(l)//T = 0.
Studies of avalanche photodiode performance in a high magnetic field

Abstract We report the results of exposing a Hamamatsu avalanche photodiode (APD) to a 7.9 T magnetic field. The effect of the magnetic field on the gain of the APD is shown and discussed. We find APD gain to be unaffected in the presence of such a magnetic field.
Optical stochastic cooling proof-of-principle experiment

Optical stochastic cooling (OSC) is a technique for cooling of charged particle beams, which has been considered for more than a decade but has yet to be experimentally demonstrated. If successfully implemented, it holds significant promise for improving the luminosity of high-energy, high-brightness beams for collider-based physics experiments. An experimental program to demonstrate and investigate OSC of stored particle beams is underway using electrons in the MIT- Bates South Hall Ring. Such studies are a necessary prerequisite to implementation in a high-energy collider environment. The South Hall Ring is a particularly suitable location for studying OSC physics due to its layout, energy range, and availability for dedicated use.
Tuning Parameter Selection in Regularized Estimations of Large Covariance Matrices

Recently many regularized estimators of large covariance matrices have been proposed, and the tuning parameters in these estimators are usually selected via cross-validation. However, there is a lack of consensus on the number of folds for conducting cross-validation. One round of cross-validation involves partitioning a sample of data into two complementary subsets, a training set and a validation set. In this manuscript, we demonstrate that if the estimation accuracy is measured in the Frobenius norm, the training set should consist of majority of the data; whereas if the estimation accuracy is measured in the operator norm, the validation set should consist of majority of the data. We also develop methods for selecting tuning parameters based on the bootstrap and compare them with their cross-validation counterparts. We demonstrate that the cross-validation methods with ‘optimal’ choices of folds are more appropriate than their bootstrap counterparts.
What Do Laboratory Experiments Measuring Social Preferences Reveal About the Real World

A critical question facing experimental economists is whether behavior inside the laboratory is a good indicator of behavior outside the laboratory. To address that question, we build a model in which the choices that individuals make depend not just on financial implications, but also on the nature and extent of scrutiny by others, the particular context in which a decision is embedded, and the manner in which participants and tasks are selected. We present empirical evidence demonstrating the importance of these various factors. To the extent that lab and naturally occurring environments systematically differ on any of these dimensions, the results obtained inside and outside the lab need not correspond. Focusing on experiments designed to measure social preferences, we discuss the extent to which the existing laboratory results generalize to naturally-occurring markets. We summarize cases where the lab may understate the importance of social preferences as well as instances in which the lab might exaggerate their importance. We conclude by emphasizing the importance of interpreting laboratory and field data through the lens of theory.
Instrumentation and Measurement of a Power Distribution System Laboratory for Meter Placement and Network Reconfiguration Studies

The monitoring and automation of power distribution systems has significantly improved with advancements in digital signal processing (DSP) and in computer and Web-based technologies. Power distribution systems could realize benefits from an improved instrumentation and measurement (IM it has a power distribution system in which various meter placements and network reconfiguration techniques can be implemented and studied. The authors designed a unique and flexible IM it can adapt to power system planning and operating scenarios. This system in the RDAC laboratory is tested and present the results in this paper.
Alternative method of Boc-removal from sulfamide using silica-phenyl sulfonic acid in conjunction with microwave heating

A general method was used to prepare an array of unsymmetric sulfamides. This was accomplished by the stepwise addition of CSI to tert-butanol followed by the addition of amines. To increase diversity, nitrogen group of Boc-sulfamides was alkylated with alcohols using Mitsunobu reaction and Boc-group was removed using Si-TsOH. Microwave heating was used in all the steps. The final sulfamides were released from Si-TsOH using NH3 in MeOH.
Level-shifter free design of low power dual supply voltage CMOS circuits using dual threshold voltages

Usage of dual supply voltages in a digital circuit is an effective way of reducing power consumption due to the quadratic relation of supply voltage to power consumption. But the need for level shifters when a low voltage gate drives a high voltage gate has been a limiting factor preventing widespread usage of dual supply voltages in digital circuit design. The overhead of level shifters forces designers to increase the granularity of dual voltage assignment, reducing the maximum obtainable savings. We propose a method of applying dual supply voltages at gate level granularity without using level shifters. We modify the threshold voltage of the high voltage gates that are driven by low voltage gates in order to obtain the level shifting operation together with the logic operation. Using our method, we obtained an average of 20% energy savings for ISCAS'85 benchmark circuits.
Numerical Anisotropy Study of a Class of Compact Schemes

We study the numerical anisotropy existent in compact difference schemes as applied to hyperbolic partial differential equations, and propose an approach to reduce this error and to improve the stability restrictions based on a previous analysis applied to explicit schemes. A prefactorization of compact schemes is applied to avoid the inversion of a large matrix when calculating the derivatives at the next time level, and a predictor---corrector time marching scheme is used to update the solution in time. A reduction of the isotropy error is attained for large wave numbers and, most notably, the stability restrictions associated with MacCormack time marching schemes are considerably improved. Compared to conventional compact schemes of similar order of accuracy, the multidimensional schemes employ larger stencils which would presumably demand more processing time, but we show that the new stability restrictions render the multidimensional schemes to be in fact more efficient, while maintaining the same dispersion and dissipation characteristics of the one dimensional schemes
Quantum Bochkov-Kuzovlev Work Fluctuation Theorems

The quantum version of the Bochkov–Kuzovlev identity is derived on the basis of the appropriate definition of work as the difference of the measured internal energies of a quantum system at the beginning and the end of an external action on the system given by a prescribed protocol. According to the spirit of the original Bochkov–Kuzovlev approach, we adopt the ‘exclusive’ viewpoint, meaning that the coupling to the external work source is not counted as part of the internal energy. The corresponding canonical and microcanonical quantum fluctuation theorems are derived as well, and are compared with the respective theorems obtained within the ‘inclusive’ approach. The relations between the quantum inclusive work w, the exclusive work w0 and the dissipated work wdis, are discussed and clarified. We show by an explicit example that w0 and wdis are distinct stochastic quantities obeying different statistics.
NATURALEZA Y CULTURA: UNA LECTURA ELEMENTAL DE ARRÁNCAME LA VIDA DE ÁNGELES MASTRETTA

Durante un periodo revolucionario la gente parece ignorar el guion que rige su conducta social. El individuo retorna a si mismo. La cultura suspende el acoso que ha impuesto en la naturaleza de la mujer. Esta puede ser leal a su naturaleza humana. Para liberarse de su circunstancia represiva Catalina Guzman necesita llevar a cabo su propia revolucion con el objeto de ser honesta a la individualidad de su naturaleza. En este su esfuerzo, la misma naturaleza, la tierra, personificada en la mujer de Atincingo asiste a Catalina en su esfuerzo. Catalina recobra su individualidad. Abstract During a revolutionary period people seem to ignore the script that rules societys social behaviour. The individual returns to him/her self. The culture stops the harassment that has been imposed on women and their nature. Women become free to be loyal to human nature. To attain a liberation of her oppressive circumstance, Catalina Guzman needs to materialize her own revolution in order to be loyal to her individuality. Supportive to her effort, nature itself, personified by the woman from Atincingo, assists Catalinas pursuit. So, Catalina recovers the freedom to be honest and loyal to herself.
Phylogenetic Uncertainties and Sensitivity Analyses in Comparative Biology

Phylogenetic comparative analyses combine information on character states and phylogenetic relationships of taxa to test hypotheses regarding character evolution. These studies encounter uncertainties at various steps, including uncertainty in the topology of phylogenetic trees, the scoring of characters, and the addition of taxa that have not explicitly been included in phylogenetic analyses. Here we highlight a variety of sensitivity tests designed to explore the robustness of comparative conclusions to changes in underlying assumptions. These include the examination of character correlations on a set of plausible phylogenetic hypotheses (including alternative rootings and `neighbouring' trees), as well as under alternative character codings. TreeBASE - a prototype relational database of phylogenetic data - should prove useful in accessing alternative hypotheses.
Discovering programming rules and violations by mining interprocedural dependences

SUMMARY This paper presents a novel approach to discovering implicit programming rules and rule violations in a code base, which integrates static interprocedural analysis and graph mining techniques to identify both function-call ordering rules and conditional rules that check input parameters or return values of functions. The approach discovers rules even when rule instances cross function boundaries. Rules are modeled as graph minors of dependence graphs augmented with edges indicating shared data dependences. The approach employs two innovative algorithms: a greedy one for mining maximal frequent minors from a set of interprocedural dependence spheres and a heuristic minor-matching algorithm for discovering rule violations. We evaluated our approach on the latest versions of three applications: net-snmp, openssl, and the Apache HTTP server. It detected 62 new bugs (24 involving rules with interprocedural instances), 35 of which have been confirmed and fixed recently by developers based on our reports. Copyright © 2011 John Wiley & Sons, Ltd.
Stellar Parameters for HD 69830, a Nearby Star with Three Neptune Mass Planets and an Asteroid Belt

We used the CHARA Array to directly measure the angular diameter of HD 69830, home to three Neptune mass planets and an asteroid belt. Our measurement of 0.674 ± 0.014 mas for the limb-darkened angular diameter of this star leads to a physical radius of R_* = 0.9058 ± 0.0190 R_☉ and luminosity of L_* = 0.622 ± 0.014 L_☉ when combined with a fit to the spectral energy distribution of the star. Placing these observed values on an Hertzsprung-Russel diagram along with stellar evolution isochrones produces an age of 10.6 ± 4 Gyr and mass of 0.863 ± 0.043 M_☉. We use archival optical echelle spectra of HD 69830 along with an iterative spectral fitting technique to measure the iron abundance ([Fe/H] = –0.04 ± 0.03), effective temperature (5385 ± 44 K), and surface gravity (log g = 4.49 ± 0.06). We use these new values for the temperature and luminosity to calculate a more precise age of 7.5 ± 3 Gyr. Applying the values of stellar luminosity and radius to recent models on the optimistic location of the habitable zone produces a range of 0.61-1.44 AU; partially outside the orbit of the furthest known planet (d) around HD 69830. Finally, we estimate the snow line at a distance of 1.95 ± 0.19 AU, which is outside the orbit of all three planets and its asteroid belt.
Synthesis of a ring a precursor of doxorubicin: Stereoselective control of the epoxidation of a homoallylic alcohol by hydroxyl and ester groups

Abstract The key step in a synthesis of a precursor for ring A in doxorubicin is the stereoselective control of the epoxidation of a homoallylic alcohol by ester and hydroxyl groups; the result leads to a new method of forming lactones in excellent yields under neutral conditions.
Mismeasured Household Size and its Implications for the Identification of Economies of Scale

We consider the possibility that demographic variables are measured with errors which arise because household surveys measure demographic structures at a point-in-time, whereas household composition evolves throughout the survey period. We construct and estimate sharp bounds on household size and find that the degree of these measurement errors is non-trivial. These errors have the potential to resolve the Deaton–Paxson paradox, but fail to do so.
Monodromy of fiber-type arrangements and orbit configuration spaces

We prove similar theorems concerning the structure of bundles involving complements of fiber-type hyperplane arrangements and orbit configuration spaces. These results facilitate analysis of the fundamental groups of these spaces, which may be viewed as generalizations of the Artin pure braid group. In particular, we resolve two disparate conjectures. We show that the Whitehead group of the fundamental group of the complement of a fiber-type arrangement is trivial, as conjectured by Aravinda, Farrell, and Rouchon. For the orbit configuration space corresponding to the natural action of a finite cyclic group on the punctured plane, we determine the structure of the Lie algebra associated to the lower central series of the fundamental group. Our results show that this Lie algebra is isomorphic to the module of primitives in the homology of the loop space of a related orbit configuration space, as conjectured by Xicotencatl. Department of Mathematics, Louisiana State University, Baton Rouge, LA 70803 E-mail address: cohen@math.lsu.edu URL: http://www.math.lsu.edu/~cohen 1991 Mathematics Subject Classification. Primary 20F36, 52B30; Secondary 19B99, 20F40.
The Mediating Effect of Psychological Capital on the Budget Participation-Job Performance Relationship

ABSTRACT: This study draws from the literature in positive psychology and organizational behavior to examine the role of an individual's psychological capital (PsyCap) on the budget participation-job performance relationship. PsyCap is an emerging construct that represents an individual's positive state of psychological development, and is characterized by the individual's hope, efficacy, optimism, and resiliency. We surveyed 109 employees working in organizations across the United States who are actively involved in the budget-setting process or have budgetary responsibilities. The results of a mediation analysis show that budget participation is significantly and positively associated with employees' levels of PsyCap, which is in turn significantly and positively associated with higher levels of job performance. Supplemental analysis using a structural equation modeling technique also supported the hypotheses of this study.
Acid catalyzed reactions of α,β-unsaturated aldehydes and ethyl diazoacetate

The formation of cyclopropanes from α,β-unsaturated aldehydes and diazo compounds has been a rather challenging goal due to the extremely reactive aldehyde starter. Herein, our group reports the first formation of ethyl 2-formyl-1-cyclopropanecarboxylate in 100% yield from the acid catalyzed reaction between acrolein and ethyl diazoacetate (EDA).
Dietary Antioxidants and Human Cancer

Epidemiological studies show that a high intake of antioxidant-rich foods is inversely related to cancer risk. While animal and cell cultures confirm the anticancer effects of antioxidants, intervention trials to determine their ability to reduce cancer risk have been inconclusive, although selenium and vitamin E reduced the risk of some forms of cancer, including prostate and colon cancer, and carotenoids have been shown to help reduce breast cancer risk. Cancer treatment by radiation and anticancer drugs reduces inherent antioxidants and induces oxidative stress, which increases with disease progression. Vitamins E and C have been shown to ameliorate adverse side effects associated with free radical damage to normal cells in cancer therapy, such as mucositis and fibrosis, and to reduce the recurrence of breast cancer. While clinical studies on the effect of antioxidants in modulating cancer treatment are limited in number and size, experimental studies show that antioxidant vitamins and some phytochemicals selectively induce apoptosis in cancer cells but not in normal cells and prevent angiogenesis and metastatic spread, suggesting a potential role for antioxidants as adjuvants in cancer therapy.
CCL20/CCR6 Feedback Exaggerates Epidermal Growth Factor Receptor-Dependent MUC5AC Mucin Production in Human Airway Epithelial (NCI-H292) Cells

Mucous hypersecretion is an important feature of obstructive airway diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Multiple stimuli induce mucin production via activation of an epidermal growth factor receptor (EGFR) cascade, but the mechanisms that exaggerate mucin production in obstructive airway diseases remain unknown. In this study, we show that binding of CCL20, a G protein-coupled receptor (GPCR) ligand that is upregulated in the airways of subjects with obstructive airway diseases, to its unique GPCR CCR6 induces MUC5AC mucin production in human airway epithelial (NCI-H292) cells via metalloprotease TNF-α-converting enzyme (TACE)-dependent EGFR activation. We also show that EGFR activation by its potent ligand TGF-α induces reactivation of EGFR via binding of endogenously produced CCL20 to its receptor CCR6 in NCI-H292 cells but not in normal human bronchial epithelial (NHBE) cells, exaggerating mucin production in the NCI-H292 cells. In NCI-H292 cells, TGF-α stimulation induced two phases of EGFR phosphorylation (EGFR-P). The second EGFR-P was TACE-dependent and was responsible for most of the total mucin induced by TGF-α. Binding of endogenously produced CCL20 to CCR6 increased the second EGFR-P and subsequent mucin production induced by TGF-α. In NHBE cells, TGF-α-induced EGFR activation did not lead to significant CCL20 production or to EGFR rephosphorylation, and less mucin was produced. We conclude that NCI-H292 cells but not NHBE cells produce CCL20 in response to EGFR activation, which leads to a second phase of EGFR-P and subsequent exaggerated mucin production. These findings have potentially important therapeutic implications in obstructive airway diseases.
Justification and Cooperation

The need for justification is a widely observed social phenomenon. This paper develops a theoretical framework and reports laboratory evidence to show how pure justification pressure affects cooperative behavior in economic exchange environments. In a one-shot anonymous interaction, compared with the case when the behavior is simply observed by the audience, individuals are more likely to act on what they believe the audience thinks they should do when they also have to explain the decisions to the audience. When it is salient that the audience thinks one should cooperate, justification pressure significantly promotes cooperation even absent negative consequences for non-cooperative behavior. We discuss the implications of our findings for shaping institutional design to promote cooperation.
Field Research Methods in Management Accounting

INTRODUCTION Field research has a very long history of application in many disciplines including anthropology, sociology and business.1 Field research differs significantly from other research methods in that trained researchers document the interactions of people as they live and work in naturally occurring settings. These characteristics make field research one of the most challenging forms of social science investigation to master. In the history of management accounting research, there have been some noteworthy field studies (cf. Simon et al. 1954; Hopwood 1972), however, prior to the early 1980s, field studies comprised less than 5 percent of published research.2 Over the past 15 years, there has been a renewed interest in conducting field studies in management accounting, particularly in manufacturing contexts. A major influence on this resurgence was the publication of Robert Kaplan’s (1983) article, “Measuring Manufacturing Performance: A New Challenge for Managerial Accounting Research.” Kaplan (1983)3 argued that global competition had altered the U.S. manufacturing environment so significantly that current management accounting methods, used for measuring manufacturing performance, were at best insufficient and at worst obsolete. Kaplan (p. 700) opined that, “if management accounting is to be a central discipline in the design and evaluation of information and control systems of corporations, the field will need to expand its vision beyond summary financial measures of manufacturing operations.” Of most relevance for this discussion, Kaplan (p. 700) suggested that “much time will need to be spent at factory sites to gain first-hand knowledge of the revolution in manufacturing technology that is occurring in many U.S. corporations.”
Joint Source Channel Coding With Side Information Using Hybrid Digital Analog Codes

We study the joint source-channel coding problem of transmitting a Gaussian source over a Gaussian channel in two cases: (i) the presence of interference known only to the transmitter and (ii) in the presence of side information about the source known only to the receiver. We introduce hybrid digital analog forms of the Costa and Wyner-Ziv coding schemes. We present the random coding counterpart of schemes based on lattices proposed by Kochman and Zamir. Then, we discuss applications of the hybrid digital analog schemes in the case of channel signal-to-noise ratio mismatch and for lossy multicasting of a common source with bandwidth compression.
Probabilistic State-Dependent Grammars for Plan Recognition

Techniques for plan recognition under uncertainty require a stochastic model of the plangeneration process. We introduce probabilistic state-dependent grammars (PSDGs) to represent an agent's plan-generation process. The PSDG language model extends probabilistic contextfree grammars (PCFGs) by allowing production probabilities to depend on an explicit model of the planning agent's internal and external state. Given a PSDG description of the plan-generation process, we can then use inference algorithms that exploit the particular independence properties of the PSDG language to efficiently answer plan-recognition queries. The combination of the PSDG language model and inference algorithms extends the range of plan-recognition domains for which practical probabilistic inference is possible, as illustrated by applications in traffic monitoring and air combat.
A learning and forgetting algorithm in associative memories: results involving pseudo-inverses

The authors develop a design technique for associative memories with learning and forgetting abilities via artificial feedback neural networks. The method utilizes the theory of large-scale interconnected dynamical systems, instead of the usual energy methods. Networks synthesized by this design method are capable of learning new patterns as well as forgetting old patterns without recomputing the entire interconnection matrix. The method, in which the properties of pseudo-inverse matrices are used to iteratively solve systems of linear equations, provides significant improvements over the outer product method and the projection learning rule. Several specific examples are given to illustrate the strengths and weaknesses of the methodology. >
Smart Grid Development Issues for Terrestrial and Space Applications

The development of the so called Smart Grid has as many definitions as individuals working in the area. Based on the technology or technologies that are of interest, be it high speed communication, renewable generation, smart meters, energy storage, advanced sensors, etc. they can become the individual defining characteristic of the Smart Grid. In reality the smart grid encompasses all of these items and quite at bit more. This discussion attempts to look at what the needs are for the grid of the future, such as the issues of increased power flow capability, use of renewable energy, increased security and efficiency and common power and data standards. It also shows how many of these issues are common with the needs of NASA for future exploration programs. A common theme to address both terrestrial and space exploration issues is to develop micro-grids that advertise the ability to enable the load leveling of large power generation facilities. However, for microgrids to realize their promise there needs to a holistic systems approach to their development and integration. The overall system integration issues are presented along with potential solution methodologies.
Agricultural Policies in the Presence of Distorting Taxes

This article analyzes how distortionary factor taxes affect the welfare impacts of production subsidies, production quotas, acreage controls, subsidies for acreage reductions, and cash transfers to farmers. Pre-existing taxes substantially raise the costs of all these policies. These additional costs reflect the welfare losses from financing certain policies by distortionary taxes. They also reflect interactions with factor markets caused by changes in the costs of producing agricultural output. Previous studies ignore the latter types of effect. Consequently they significantly overstate the costs of production subsidies and understate the costs of production quotas, acreage controls, and subsidies for acreage reductions.
Universal two-step crystallization of DNA-functionalized nanoparticles

We examine the crystallization dynamics of nanoparticles reversibly tethered by DNA hybridization. We show that the crystallization happens readily only in a narrow temperature “slot”, and always proceeds via a two-step process, mediated by a highly-connected amorphous intermediate. For lower temperature quenches, the dynamics of unzipping strands in the amorphous state is sufficiently slow that crystallization is kinetically hindered. This accounts for the well-documented difficulty of forming crystals in these systems. The strong parallel to the crystallization behavior of proteins and colloids suggests that these disparate systems crystallize in an apparently universal manner.
Aggregate productivity and aggregate technology

Abstract Aggregate productivity and aggregate technology are meaningful but distinct concepts. We show that a slightly modified Solow productivity residual measures changes in economic welfare, even when productivity and technology differ because of distortions such as imperfect competition. Our results imply that aggregate data can be used to measure changes in welfare, even when disaggregated data are needed to measure technical change. We then present a general accounting framework that identifies several new non-technological gaps between productivity and technology, gaps reflecting imperfections and frictions in output and factor markets. Empirically, we find that these gaps are important, even though we abstract from variations in factor utilization and estimate only small average sectoral markups. The evidence suggests that the usual focus on one-sector DSGE models misses a rich class of important propagation mechanisms that are present only in multi-sector models.
Framework for the Analysis of the Adaptability, Extensibility, and Scalability of Semantic Information Integration and the Context Mediation Approach

Technological advances such as Service Oriented Architecture (SOA) have increased the feasibility and importance of effectively integrating information from an ever widening number of systems within and across enterprises. A key difficulty of achieving this goal comes from the pervasive heterogeneity in all levels of information systems. A robust solution to this problem needs to be adaptable, extensible, and scalable. In this paper, we identify the deficiencies of traditional semantic integration approaches. The COntext INterchange (COIN) approach overcomes these deficiencies by declaratively representing data semantics and using a mediator to create the necessary conversion programs from a small number of conversion rules. The capabilities of COIN is demonstrated using an example with 150 data sources, where COIN can automatically generate the over 22,000 conversion programs needed to enable semantic interoperability using only six parametizable conversion rules. This paper presents a framework for evaluating adaptability, extensibility, and scalability of semantic integration approaches. The application of the framework is demonstrated with a systematic evaluation of COIN and other commonly practiced approaches.
Decentralized intersection management through peer-to-peer technology

In this paper we present two new decentralized algorithms for autonomous intersection management and compare the performance of the algorithms with an established centralized solution. One of the algorithms addresses the problem through an unstructured peer-to-peer approach and the other uses a Distributed Hash Table to distribute knowledge of intersection usage among participating vehicles. We evaluate these algorithms through simulation and by comparing average delay to the performance of a centralized reservation-based algorithm. We find that in times of light congestion the decentralized algorithms perform as well as the centralized approach. During times of moderate or heavy congestion the unstructured peer-to-peer algorithm performs better than the centralized algorithm, and the DHT-based algorithm performs worse.
Multiagent negotiation for fair and unbiased resource allocation

This paper proposes a novel solution for the n agent cake cutting (resource allocation) problem. We propose a negotiation protocol for dividing a resource among n agents and then provide an algorithm for allotting portions of the resource. We prove that this protocol can enable distribution of the resource among n agents in a fair manner. The protocol enables agents to choose portions based on their internal utility function, which they do not have to reveal. In addition to being fair, the protocol has desirable features such as being unbiased and verifiable while allocating resources. In the case where the resource is two-dimensional (a circular cake) and uniform, it is shown that each agent can get close to 1/n of the whole resource.
AN ANALYSIS OF THE EFFECT OF GHOST FORCE OSCILLATION ON QUASICONTINUUM ERROR

The atomistic to continuum interface for quasicontinuum energies exhibits nonzero forces under uniform strain that have been called ghost forces. In this paper, we prove for a linearization of a one-dimensional quasicontinuum energy around a uniform strain that the effect of the ghost forces on the displacement nearly cancels and has a small effect on the error away from the interface. We give optimal order error estimates that show that the quasicontinuum displacement converges to the atomistic displacement at the rate O(h) in the discrete � ∞ and w 1,1 norms where h is the interatomic spacing. We also give a proof that the error in the displacement gradient decays away from the interface to O(h )a t distance O(h| log h|) in the atomistic region and distance O(h) in the continuum region. Our work gives an explicit and simplified form for the decay of the effect of the atomistic to continuum coupling error in terms of a general underlying interatomic potential and gives the estimates described above in the discrete � ∞ and w 1,p norms.
Single-mode fiber-optic components

In the process of studying single-mode fiber optic systems it became rapidly apparent a few years ago that it would be desirable to perform a number of functions with in-line components, which would allow for signal processing without the removal of the optical signal from the fiber. Some advantages of single-mode fiber optic components over conventional bulk optic components would be reduction of insertion loss, high stability, and compactness. They would also be free of difficulties involved in interfacing their integrated optic counterparts to single mode fiber optic systems.
Imprinting analysis in the acrodysplasia region of mouse chromosome 12

The insertional mouse mutation Adp (Acrodysplasia) confers a parent-of-origin developmental phenotype, with animals inheriting the mutation from their father showing skeletal abnormalities, whereas those inheriting the mutation from their mother are normal. This parental-specific phenotype, along with mapping of the insertion to a region of chromosome 12 proposed to contain imprinted genes, suggested that disruption of genomic imprinting might underlie the Adp phenotype. Genomic imprinting is the process by which autosomal genes are epigenetically silenced on one of the two parental alleles; imprinting mutation phenotypes manifest after inheritance from one parent but not the other. Imprinted genes typically occur in dense clusters that contain few non-imprinted genes and therefore representative genes from the Adp critical region could be assayed to identify any imprinted domains. None of the genes analysed were found to be imprinted, however, suggesting that other explanations for the Adp phenotype must be considered.
Seismic evidence for lithospheric modification beneath the Mojave Neovolcanic Province, Southern California

[1] The Mojave Neovolcanic Province (MNVP), located in the Mojave block of southern California, comprises late Miocene to Quaternary small-volume basaltic centers. Geochemistry indicates an asthenospheric source for the MNVP beginning in the late Miocene, but no physical evidence of missing mantle lithosphere has been presented. We utilize receiver functions and ambient noise tomography to image the lithosphere beneath the Mojave block. Regionally, we find thin crust that thickens distal to sites of MNVP volcanism. Shear wave velocities between 40 and 75 km depth are consistent with the presence of mantle lithosphere in the southern Mojave block and very thin or missing mantle lithosphere to the north. With one exception, MNVP volcanoes lie along this sharp boundary. Our observations, together with the established geologic history and geochemistry of the MNVP, can be explained by small-scale edge-driven convection producing ongoing lithospheric removal within the Mojave block. Our results provide another example of lithospheric instability that occurs in response to rapid changes in mantle dynamics induced by major changes in tectonic plate geometry.
Scalable Inference for Neuronal Connectivity from Calcium Imaging

Fluorescent calcium imaging provides a potentially powerful tool for inferring connectivity in neural circuits with up to thousands of neurons. However, a key challenge in using calcium imaging for connectivity detection is that current systems often have a temporal response and frame rate that can be orders of magnitude slower than the underlying neural spiking process. Bayesian inference methods based on expectation-maximization (EM) have been proposed to overcome these limitations, but are often computationally demanding since the E-step in the EM procedure typically involves state estimation for a high-dimensional nonlinear dynamical system. In this work, we propose a computationally fast method for the state estimation based on a hybrid of loopy belief propagation and approximate message passing (AMP). The key insight is that a neural system as viewed through calcium imaging can be factorized into simple scalar dynamical systems for each neuron with linear interconnections between the neurons. Using the structure, the updates in the proposed hybrid AMP methodology can be computed by a set of one-dimensional state estimation procedures and linear transforms with the connectivity matrix. This yields a computationally scalable method for inferring connectivity of large neural circuits. Simulations of the method on realistic neural networks demonstrate good accuracy with computation times that are potentially significantly faster than current approaches based on Markov Chain Monte Carlo methods.
Lewis acid-promoted addition of allyl(cyclopentadienyl)iron(II) dicarbonyl to aldehydes: a new aldehyde allylation method

Abstract The Lewis acid-promoted addition of allyliron(II) reagent 4 to aldehydes provides zwitterionic iron-olefin complexes 7 as isolable yellow salts. Treatment of the iron complexes with NaI in wet acetone affords homoallylic alcohols 8 .
Suicidal ideation and pharmacotherapy among STEP-BD patients

OBJECTIVE: Little is known about the effects of lithium on suicidal ideation or about the possible antisuicidal effects of divalproex, second-generation antipsychotics, or antidepressants among persons with bipolar disorder. METHODS: Using a cross-sectional design, the authors examined patterns of psychotropic drug use relative to suicidal ideation among 1,000 patients with bipolar disorder in the National Institute of Mental Health's Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD). RESULTS: The presence of suicidal ideation was similar between patients who were taking any lithium and those who were not (22.2 percent and 25.8 percent, respectively) and between those who were taking any divalproex and those who were not (20.3 percent and 21.5 percent). Suicidal ideation was significantly more prevalent among patients who were taking a second-generation antipsychotic than those who were not (26 percent and 17 percent) and those who were taking an antidepressant and those who were not...
Responsiveness in Low Orbits using Electric Propulsion

One promising option for space operational responsiveness is orbital maneuvering. In low orbit, a maneuverable spacecraft can provide valuable benefits such as better coverage properties, reduced revisit times, selectable targets, and local overflight times. Such maneuvers are not common due to the high cost of chemical propulsion. The more recent paradigm of operationally responsive space is to rapidly launch a small inexpensive asset and use it in a short disposable fashion. This concept relies on drastically reducing the cost of launch, yet it remains the most expensive piece, and so additional cost savings can be realized by minimizing the need for launches. Electric propulsion has been considered as an efficient alternative to chemical propulsion. With technological advances, electric propulsion can provide responsiveness in a timely propellant-efficient manner without requiring repeated launches to satisfy multiple missions. This study shows the control algorithm for a single low-Earth satellite equ...
t-Pebbling and Extensions

Graph pebbling is the study of moving discrete pebbles from certain initial distributions on the vertices of a graph to various target distributions via pebbling moves. A pebbling move removes two pebbles from a vertex and places one pebble on one of its neighbors (losing the other as a toll). For t ? 1 the t-pebbling number of a graph is the minimum number of pebbles necessary so that from any initial distribution of them it is possible to move t pebbles to any vertex. We provide the best possible upper bound on the t-pebbling number of a diameter two graph, proving a conjecture of Curtis et al., in the process. We also give a linear time (in the number of edges) algorithm to t-pebble such graphs, as well as a quartic time (in the number of vertices) algorithm to compute the pebbling number of such graphs, improving the best known result of Bekmetjev and Cusack. Furthermore, we show that, for complete graphs, cycles, trees, and cubes, we can allow the target to be any distribution of t pebbles without increasing the corresponding t-pebbling numbers; we conjecture that this behavior holds for all graphs. Finally, we explore fractional and optimal fractional versions of pebbling, proving the fractional pebbling number conjecture of Hurlbert and using linear optimization to reveal results on the optimal fractional pebbling number of vertex-transitive graphs.
Revising the Age for the Baptistina Asteroid Family Using WISE/NEOWISE Data

We have used numerical routines to model the evolution of a simulated Baptistina family to constrain its age in light of new measurements of the diameters and albedos of family members from the Wide-field Infrared Survey Explorer. We also investigate the effect of varying the assumed physical and orbital parameters on the best-fitting age. We find that the physically allowed range of assumed values for the density and thermal conductivity induces a large uncertainty in the rate of evolution. When realistic uncertainties in the family members' physical parameters are taken into account, we find that the best-fitting age can fall anywhere in the range of 140-320 Myr. Without more information on the physical properties of the family members, it is difficult to place a more firm constraint on Baptistina's age.
A Bayesian Approach for Fast and Accurate Gene Tree Reconstruction

Recentsequencingandcomputingadvanceshaveenabledphylogeneticanalysestoexpandtobothentiregenomesandlarge clades, thus requiring more efficient and accurate methods designed specifically for the phylogenomic context. Here, we present SPIMAP, an efficient Bayesian method for reconstructing gene trees in the presence of a known species tree. We observemany improvementsinreconstructionaccuracy, achievedby modelingmultipleaspectsofevolution,includinggene duplication and loss (DL) rates, speciationtimes, andcorrelated substitutionrate variationacross both species and loci. We have implemented and appliedthis method on two clades of fully sequenced species,12 Drosophila and 16 fungal genomes as well as simulated phylogenies and find dramatic improvements in reconstruction accuracy as compared with the most popularexistingmethods,includingthosethattakethespeciestreeintoaccount.Wefindthatreconstructioninaccuraciesof traditionalphylogeneticmethodsoverestimatethenumberofDLeventsbyasmuchas2‐3-fold,whereasourmethodachieves significantlyhigher accuracy. We feelthattheresultsandmethods presentedhere willhave manyimportantimplicationsfor future investigationsofgene evolution.