Bubble vector in automatic merging

It is shown that it is within the capability of the DMAP language to build a set of vectors that can grow incrementally to be applied automatically and economically within a DMAP loop that serves to append sub-matrices that are generated within a loop to a core matrix. The method of constructing such vectors is explained

Features in the ion emission of Cu, Al, and C plasmas produced by ultrafast laser ablation

© 2015 AIP Publishing LLC. The bi-modal nature of charge integrated ion kinetic energy distributions, which result from ultrafast laser produced plasmas, is discussed in this paper. A negatively biased Faraday cup was used as a charge collector to measure ion distributions from three different solid targets that had been irradiated with an ultrafast laser in the fluence range 0.1-1 J/cm2. A bi-modal time of flight distribution is found for all three targets (C, Al, and Cu). In the case of the metallic targets (Al and Cu), high- and low-kinetic energy peaks exhibit quite different dependencies on laser fluence, whereas for the semi-metallic target (C), both peaks scale similarly with ultrafast laser fluence. The results are discussed within the framework of a one dimensional capacitor model resulting in ion acceleration

Self-referential order

We introduce the concept of self-referential order which provides a way to quantify structural organization in non-crystalline materials. The key idea consists in the observation that, in a disordered system, where there is no ideal, reference, template structure, each sub-portion of the whole structure can be taken as reference for the rest and the system can be described in terms of its parts in a self-referential way. Some parts carry larger information about the rest of the structure and they are identified as motifs. We discuss how this method can efficiently reduce the amount of information required to describe a complex disordered structure by encoding it in a set of motifs and matching rules. We propose an information-theoretic approach to define a self-referential-order-parameter and we show that, by means of entropic measures, such a parameter can be quantified explicitly. A proof of concept application to equal disk packing is presented and discussed

Splitting The Gluon?

In the strongly correlated environment of high-temperature cuprate superconductors, the spin and charge degrees of freedom of an electron seem to separate from each other. A similar phenomenon may be present in the strong coupling phase of Yang-Mills theories, where a separation between the color charge and the spin of a gluon could play a role in a mass gap formation. Here we study the phase structure of a decomposed SU(2) Yang-Mills theory in a mean field approximation, by inspecting quantum fluctuations in the condensate which is formed by the color charge component of the gluon field. Our results suggest that the decomposed theory has an involved phase structure. In particular, there appears to be a phase which is quite reminiscent of the superconducting phase in cuprates. We also find evidence that this phase is separated from the asymptotically free theory by an intermediate pseudogap phase.Comment: Improved discussion of magnetic nature of phases; removed unsubstantiated speculation about color confinemen

Planetary Bistatic Radar

Planetary radar observations offer the potential for probing the properties of characteristics of solid bodies throughout the inner solar system and at least as far as the orbit of Saturn. In addition to the direct scientific value, precise orbital determinations can be obtained from planetary radar observations, which are in turn valuable for mission planning or spacecraft navigation and planetary defense. The next-generation Very Large Array would not have to be equipped with a transmitter to be an important asset in the world's planetary radar infrastructure. Bistatic radar, in which one antenna transmits (e.g., Arecibo or Goldstone) and another receives, are used commonly today, with the Green Bank Telescope (GBT) serving as a receiver. The improved sensitivity of the ngVLA relative to the GBT would improve the signal-to-noise ratios on many targets and increase the accessible volume specifically for asteroids. Goldstone-ngVLA bistatic observations would have the potential of rivaling the sensitivity of Arecibo, but with much wider sky access.Comment: 11 pages, 2 figures, To be published in the ASP Monograph Series, "Science with a Next-Generation VLA", ed. E. J. Murphy (ASP, San Francisco, CA

A Repost On a Survey of Sociology in South in South Dakota\u27s Colleges and Universities

This report is based on a survey of the current status of sociology in the colleges and universities of South Dakota conducted in February and March of 1972 and covers the academic year of 1971-72. The authors sincerely hope that the information contained in this report will serve to increase the awareness of Sociology as a viable academic discipline in the colleges in South Dakota and to acquaint the members of the profession with their colleagues engaged in this enterprise. The authors wish to express their warm appreciation to those colleagues that cooperated by responding to a rather lengthy questionnaire. Their efforts made the project a success with returns being received from all of the seven state supported institutions and seven private colleges

Time-varying Learning and Content Analytics via Sparse Factor Analysis

We propose SPARFA-Trace, a new machine learning-based framework for time-varying learning and content analytics for education applications. We develop a novel message passing-based, blind, approximate Kalman filter for sparse factor analysis (SPARFA), that jointly (i) traces learner concept knowledge over time, (ii) analyzes learner concept knowledge state transitions (induced by interacting with learning resources, such as textbook sections, lecture videos, etc, or the forgetting effect), and (iii) estimates the content organization and intrinsic difficulty of the assessment questions. These quantities are estimated solely from binary-valued (correct/incorrect) graded learner response data and a summary of the specific actions each learner performs (e.g., answering a question or studying a learning resource) at each time instance. Experimental results on two online course datasets demonstrate that SPARFA-Trace is capable of tracing each learner's concept knowledge evolution over time, as well as analyzing the quality and content organization of learning resources, the question-concept associations, and the question intrinsic difficulties. Moreover, we show that SPARFA-Trace achieves comparable or better performance in predicting unobserved learner responses than existing collaborative filtering and knowledge tracing approaches for personalized education

Measuring surface-area-to-volume ratios in soft porous materials using laser-polarized xenon interphase exchange NMR

We demonstrate a minimally invasive nuclear magnetic resonance (NMR) technique that enables determination of the surface-area-to-volume ratio (S/V) of soft porous materials from measurements of the diffusive exchange of laser-polarized 129Xe between gas in the pore space and 129Xe dissolved in the solid phase. We apply this NMR technique to porous polymer samples and find approximate agreement with destructive stereological measurements of S/V obtained with optical confocal microscopy. Potential applications of laser-polarized xenon interphase exchange NMR include measurements of in vivo lung function in humans and characterization of gas chromatography columns.Comment: 14 pages of text, 4 figure

Valuing the risk associated with willow and miscanthus relative to conventional agricultural systems

The agronomic characteristics of willow and miscanthus make these crops highly susceptible to risk. This is particularly true in a country such as Ireland which has limited experience in the production of these crops. Issues such as soil and climate suitability have as yet to be resolved. The lengthy production lifespan of energy crops only serve to heighten the level of risk that affects key variables. The uncertainty surrounding the risk variables involved in producing willow and miscanthus, such as the annual yield level and the energy price, make it difficult to accurately calculate the returns of such a project. The returns from willow and miscanthus are compared with those of conventional agricultural enterprises using Stochastic Efficiency with Respect to a Function (SERF). A risk premium is calculated which farmers would need to be compensated with in order for them to be indifferent between their current enterprise and switching to biomass crop production. With the exception of spring barley, a risk premium is required if farmers are to be indifferent between their current enterprise and willow or miscanthus. The value of the risk premium required to entice farmers to switch to miscanthus production is significantly less than that required for willow. This suggests that a greater level of risk is associated with willow than with miscanthus.Biomass, SERF, Risk Premium, Resource /Energy Economics and Policy, Risk and Uncertainty,