6,089 research outputs found

    Maximizing the Impact of Professional Development for Earth Science Teachers

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    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 CLIPS prototype for autonomous power system control

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    The model of the system assumes a constant power source and loads (experiments) whose power demands exceed the supply. Experiments are described by their name, power consumption, time for a complete run, present status and the state of the load. The power consumption of each load is set at a constant level but can be dynamically modified by the operator. The status specifies if the experiment is running, paused, completed or failed. The state compensates for the lack of actual feedback sensor data, by signifying the stability of the load. Experiments are scheduled to keep as many running as possible with the current system limitations. A graphics oriented user interface is embedded into the rule-based system to enable an operator to easily experiment with the system

    A New Technique for System-to-system Transfer of Surface Data

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    The purpose is to describe a recently developed technique aimed at providing a universal interface between surface types. In brief, a software package was developed which functions a common denominator of CAD/CAM surface types. This software enable one to convert from any given surface representation to any other target representation. The tiles maintain the same slope continuity as the target surface gram, bicubic patches are used since they allow one to match point, slope, and twist vectors to the target surface. Thus, slopes can be continuous or discontinuous as they are on the target surface. The patches can be of lower order if desired. For example, if only point information is available, the patches produced will be bilinear; however, the number of patches required is likely to increase correspondingly. The patches can be of higher order although many systems will not accept patches of more than order four. The final result of the program is a rectangular grid of bicubic patches. The patches fit the target surface exactly at their corners. Also, the patch corners have the same tangent and twist vectors. Adjacent patches will have slope continuity, unless a discontinuity was indicated by the target surface

    Interactive Simplifier Tracing and Debugging in Isabelle

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    The Isabelle proof assistant comes equipped with a very powerful tactic for term simplification. While tremendously useful, the results of simplifying a term do not always match the user's expectation: sometimes, the resulting term is not in the form the user expected, or the simplifier fails to apply a rule. We describe a new, interactive tracing facility which offers insight into the hierarchical structure of the simplification with user-defined filtering, memoization and search. The new simplifier trace is integrated into the Isabelle/jEdit Prover IDE.Comment: Conferences on Intelligent Computer Mathematics, 201

    A TALE OF TWO ENVYS: A SOCIAL NETWORK PERSPECTIVE ON THE CONSEQUENCES OF WORKPLACE SOCIAL COMPARISON

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    My dissertation examines how individuals respond to workplace social comparisons. I measure the explicit set of referent others that individuals compare themselves against in order to evaluate their own level of performance. I examine how the social context of these comparisons impact discretionary performance related behaviors by examining how an individual’s position within a social network and the structural characteristics of an individual’s reference group influences the experience of discrete emotions. Specifically, I examine how malicious envy and benign envy mediate the relationship between social comparison and workplace behavior in a field setting. Results indicate that social network structure plays a significant role in motivating both productive and counterproductive responses to social comparison. Whether or not an employee responds to upward social comparisons by increasing their own work effort or engaging in deviant behavior is influenced by the experience of benign and malicious envy, which is in turn influencedby the network structure of reference groups. Furthermore, social network position plays a moderating role in the occurrence of workplace deviance by either enhancing or limiting the opportunities an employee has to engage in deviant behavior

    Enabling Sum Frequency Spectroscopy and Fluorescence Correlation Spectroscopy of Model Cellular Membranes

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    The majority of proteins secreted from cells contain a signal peptide sequence that is required for secretion mediated by the endoplasmic reticulum and Golgi apparatus. However, many proteins lack the essential signal peptide sequence, yet still undergo secretion. Such proteins are known to regulate cell proliferation, differentiation, and migration. Fibroblast growth factor 1 (FGF-1) is one protein which undergoes non-classical protein transport. The role of its interactions with the cellular membrane during non-classical protein transport is not fully understood, although FGF-1 has shown preferential destabilizing effects on artificial membranes composed of acidic phospholipids. In the present work, physiologically relevant model membrane systems have been developed and characterized in order to investigate the role of phospholipid:FGF-1 interactions in translocation of the protein across the membrane. In addition, a confocal z-scan fluorescence correlation spectrometer (z-scan FCS) and a sum frequency spectrometer (SFS) have been assembled, and temperature controlled liquid sample holders have been designed and fabricated. Z-scan FCS and SFS have been employed to characterize the model membrane systems and have been shown to be suitable tools for elucidating the role of specific phospholipid:FGF-1 interactions in transmembrane translocation

    Hormone Mediated Transport of Calcium and Phosphate in Polarized Epithelial Cells

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    The effects of 1,25(OH)2D3, PTH and 25(OH)D3 on phosphate or calcium uptake were studied in cultured, adherent chick enterocytes over a period of 10 min after hormone addition. Time course studies of cells treated with 130 pM 1,25(OH)2D3 showed an increase in 32P uptake as early as 3 min. Similar studies with 65 pM bPTH(l1-34) resulted in an increase in 45Ca uptake only if the cells had been cultured in serum. (OH)D3, which is not firmly established as an active metabolite of vitamin D, was shown to increase 45Ca uptake within 5 min at a 100 nM concentration. Analyses of signal transduction events involving each hormone were undertaken using PKC and PKA inhibitors, chelerythrine and Rp-cAMP, respectively. In the presence of PKC inhibitor and 1,25(OH)2D3 elevated 32P levels were apparent; however, further investigations involving efflux studies showed PKC inhibition of 32P extrusion in the presence or absence of hormone. On the other hand, suppression of the PKA pathway stimulated an increase in 1,25(OH)2D3-mediated 32P uptake. Preincubation of enterocytes with Ab099 against a putative membrane receptor for 1,25(OH)2D3 abolished steroid-stimulated 32P uptake. While PKC inhibition had no effect on 45Ca uptake in enterocytes exposed to 65 pM bPTH(1-34) in serum, pretreatment with PKA inhibitor resulted in 45Ca levels relatively close to basal levels. Cells pretreated with PKC inhibitor and exposed to 25(OH)D3 demonstrated no changes in 45Ca levels, whereas inhibition of PKA induced decreased 45Ca levels after 10 min of incubation. In equivalent time course studies of membrane trafficking using confocal microscopy, potential vectorial transport initiated by each hormone was analyzed with agonist alone or in the presence of PKC and PKA inhibitors. In addition 1,25(OH)2D3 was tested in the presence of Ab099 against its putative membrane receptor. Visualization of these experiments using the endocytotic marker dye, FM 1-43, demonstrated that hormone-mediated membrane trafficking is rapid enough to contribute to ion transport. These results also suggest that vectorial vesicular transport mechanisms were involved to some extent in response to each hormone. Moreover, the pattern for membrane trafficking was different for each agonist. These combined results indicate that adherent chick enterocytes demonstrate hormone-mediated uptake that occurs more rapidly than cells in suspension or in perfusion studies. This research supports previous studies that identify 25(OH)D3 as an active vitamin D metabolite. The PKA signal transduction pathway is a possible mechanism for PTH- and 25(OH)D3-mediated increases in 45Ca. In addition, a central role for the basal lateral membrane receptor protein, 1,25(OH)2D3MARRS-bp, in 1,25(OH)2D3-mediated 32P uptake is supported. Confocal imaging suggests that the transport mechanism for phosphate or calcium ions in the presence of these hormones involves vesicular carriers

    Measuring microsatellite conservation in mammalian evolution with a phylogenetic birth-death model.

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    Microsatellites make up ∼3% of the human genome, and there is increasing evidence that some microsatellites can have important functions and can be conserved by selection. To investigate this conservation, we performed a genome-wide analysis of human microsatellites and measured their conservation using a binary character birth--death model on a mammalian phylogeny. Using a maximum likelihood method to estimate birth and death rates for different types of microsatellites, we show that the rates at which microsatellites are gained and lost in mammals depend on their sequence composition, length, and position in the genome. Additionally, we use a mixture model to account for unequal death rates among microsatellites across the human genome. We use this model to assign a probability-based conservation score to each microsatellite. We found that microsatellites near the transcription start sites of genes are often highly conserved, and that distance from a microsatellite to the nearest transcription start site is a good predictor of the microsatellite conservation score. An analysis of gene ontology terms for genes that contain microsatellites near their transcription start site reveals that regulatory genes involved in growth and development are highly enriched with conserved microsatellites
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