3,783 research outputs found
Maximizing the Impact of Professional Development for Earth Science Teachers
This study examines the extent to which follow-up sessions can provide support for earth science teachers as they apply what they learn from professional development coursework during the academic year with their own students. Data include direct observation of follow-up sessions of courses for teachers; interviews with course co-instructors and teacher participants; and, document analysis of teacher products with a focus on the lesson plans, laboratory/activity sheets for students, and virtual field trips that teacher participants submitted and shared during follow-up sessions. Strategies are recommended to assist earth science content faculty in increasing the impact of their work with teachers and hence, student instruction
A preliminary review of organic materials single crystal growth by the Czochralski technique
The growth of single crystals of organic compounds by the Czochralski method is reviewed. From the literature it is found that single crystals of benzil, a nonlinear optical material with a d sub 11 value of 11.2 + or - 1.5 x d sub 11 value of alpha quartz, has fewer dislocations than generally contained in Bridgman crystals. More perfect crystals were grown by repeated Czochralski growth. This consists of etching away the defect-containing portion of a Czochralski grown crystal and using it as a seed for further growth. Other compounds used to grow single crystals are benzophenone, 12-tricosanone (laurone), and salol. The physical properties, growth apparatus, and processing conditions presented in the literature are discussed. Moreover, some of the possible advantages of growing single crystals of organic compounds in microgravity to obtain more perfect crystals than on Earth are reviewed
Bayesian optimization for materials design
We introduce Bayesian optimization, a technique developed for optimizing
time-consuming engineering simulations and for fitting machine learning models
on large datasets. Bayesian optimization guides the choice of experiments
during materials design and discovery to find good material designs in as few
experiments as possible. We focus on the case when materials designs are
parameterized by a low-dimensional vector. Bayesian optimization is built on a
statistical technique called Gaussian process regression, which allows
predicting the performance of a new design based on previously tested designs.
After providing a detailed introduction to Gaussian process regression, we
introduce two Bayesian optimization methods: expected improvement, for design
problems with noise-free evaluations; and the knowledge-gradient method, which
generalizes expected improvement and may be used in design problems with noisy
evaluations. Both methods are derived using a value-of-information analysis,
and enjoy one-step Bayes-optimality
Isolation of high molecular weight DNA from Neurospora
Isolation of high molecular weight DNA from Neurospor
Continuous Wavelets on Compact Manifolds
Let be a smooth compact oriented Riemannian manifold, and let
be the Laplace-Beltrami operator on . Say 0 \neq f
\in \mathcal{S}(\RR^+), and that . For , let
denote the kernel of . We show that is
well-localized near the diagonal, in the sense that it satisfies estimates akin
to those satisfied by the kernel of the convolution operator on
\RR^n. We define continuous -wavelets on , in such a
manner that satisfies this definition, because of its localization
near the diagonal. Continuous -wavelets on are analogous to
continuous wavelets on \RR^n in \mathcal{S}(\RR^n). In particular, we are
able to characterize the Hlder continuous functions on by
the size of their continuous wavelet transforms, for
Hlder exponents strictly between 0 and 1. If is the torus
\TT^2 or the sphere , and (the ``Mexican hat''
situation), we obtain two explicit approximate formulas for , one to be
used when is large, and one to be used when is small
Kinetic Studies on Photodeposition of Polydiacetylene Thin Film from Solution: Preliminary Determination of the Rate Law
Preliminary kinetic studies were undertaken on the photodeposition of thin films of a polydiacetylene derivative of 2-methyl-4-nitroaniline from monomer solutions onto quartz substrates. Solutions of the monomer, DAMNA, in 1,2-dichloroethane at various concentrations were irradiated at 364 nm using an argon-ion laser at several intensities. It was found that the rate of polydiacetylene (PDAMNA) film photodeposition varies linearly with UV light intensity and as the square root of monomer concentration
Investigating the veracity of self-reported post-traumatic growth: a profile analysis approach
Research into posttraumatic growth—positive psychological change that people report in their relationships, priorities in life, and self-perception after experiences of adversity—has been severely critiqued. We investigated the degree to which community members’ friends and relatives corroborated targets’ self-perceived positive and negative changes as measured by the Posttraumatic Growth Inventory-42. We found corroboration only for negative changes when we examined overall (averaged) scores. However, using a profile analysis procedure, we found significant participant–informant agreement on the domains of change that had relatively higher scores in the target’s profile and those that had relatively lower scores. Our results demonstrate that informants were able to observe that targets had changed and were sensitive to the idiosyncratic ways in which these changes had manifested in targets’ behavior
Separation processes during binary monotectic alloy production
Observation of microgravity solidification processes indicates that outside of sedimentation, at least two other important effects can separate the phases: critical-point wetting and spreading; and thermal migration of second-phase droplets due to interfacial tension gradients. It is difficult to study these surface tension effects while in a unit gravity field. In order to investigate the processes occurring over a temperature range, i.e., between a consolute point and the monotectic temperature, it is necessary to use a low-gravity environment. The MSFC drop tube (and tower), the ballistic trajectory KC-135 airplane, and the Space Shuttle are ideal facilities to aid formation and testing of hypotheses. Much of the early work in this area focuses on transparent materials so that process dynamics may be studied by optical techniques such as photography for viewing macro-processes; holography for studying diffusional growth; spinodal decomposition and coalescence; ellipsometry for surface wetting and spreading effects; and interferometry and spectroscopy for small-scale spatial resolution of concentration profiles
Bounded prefix-suffix duplication
We consider a restricted variant of the prefix-suffix duplication operation, called bounded prefix-suffix duplication. It consists in the iterative duplication of a prefix or suffix, whose length is bounded by a constant, of a given word. We give a sufficient condition for the closure under bounded prefix-suffix duplication of a class of languages. Consequently, the class of regular languages is closed under bounded prefix-suffix duplication; furthermore, we propose an algorithm deciding whether a regular language is a finite k-prefix-suffix duplication language. An efficient algorithm solving the membership problem for the k-prefix-suffix duplication of a language is also presented. Finally, we define the k-prefix-suffix duplication distance between two words, extend it to languages and show how it can be computed for regular languages
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The role of animacy in children's interpretation of relative clauses in English: evidence from sentence-picture matching and eye movements
Subject relative clauses (SRCs) are typically processed more easily than object relative clauses (ORCs), but this difference is diminished by an inanimate head-noun in semantically non-reversible ORCs ("The book that the boy is reading"). In two eye-tracking experiments, we investigated the influence of animacy on online processing of semantically reversible SRCs and ORCs using lexically inanimate items that were perceptually animate due to motion (e.g., "Where is the tractor that the cow is chasing"). In Experiment 1, 48 children (aged 4;5-6;4) and 32 adults listened to sentences that varied in the lexical animacy of the NP1 head-noun (Animate/Inanimate) and relative clause (RC) type (SRC/ORC) with an animate NP2 while viewing two images depicting opposite actions. As expected, inanimate head-nouns facilitated the correct interpretation of ORCs in children; however, online data revealed children were more likely to anticipate an SRC as the RC unfolded when an inanimate head-noun was used, suggesting processing was sensitive to perceptual animacy. In Experiment 2, we repeated our design with inanimate (rather than animate) NP2s (e.g., "where is the tractor that the car is following") to investigate whether our online findings were due to increased visual surprisal at an inanimate as agent, or to similarity-based interference. We again found greater anticipation for an SRC in the inanimate condition, supporting our surprisal hypothesis. Across the experiments, offline measures show that lexical animacy influenced children's interpretation of ORCs, whereas online measures reveal that as RCs unfolded, children were sensitive to the perceptual animacy of lexically inanimate NPs, which was not reflected in the offline data. Overall measures of syntactic comprehension, inhibitory control, and verbal short-term memory and working memory were not predictive of children's accuracy in RC interpretation, with the exception of a positive correlation with a standardized measure of syntactic comprehension in Experiment 1
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