3,378 research outputs found

    The Objectives of Student Discipline and The Process Thatā€™s Due: Are They Compatible?

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    The disciplinary process on campuses has been too procedural and mirrors an adversarial proceeding that precludes student development. Suggestions for a paired down process allowing for student learning are provided

    Density matrix renormalisation group study of the correlation function of the bilinear-biquadratic spin-1 chain

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    Using the recently developed density matrix renormalization group approach, we study the correlation function of the spin-1 chain with quadratic and biquadratic interactions. This allows us to define and calculate the periodicity of the ground state which differs markedly from that in the classical analogue. Combining our results with other studies, we predict three phases in the region where the quadratic and biquadratic terms are both positive.Comment: 13 pages, Standard Latex File + 5 PostScript figures in separate (New version with SUBSTANTIAL REVISIONS to appear in J Phys A

    Gas Chromortographic Analyses of Biocrude-Producing Trees

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    Gas chromotographic procedures were used to compare commercial diesel fuel with cyclohexane, ether, and methanol extracts from various tree species. Standard n-paraffin hydrocarbons ranging from C-10 thru C-34 were used as standards. These analyses indicated that several extracts, notably those from Juniper virginiana (juniper) and Pinus echinata (pine) trees of Northeast Arkansas and the Brazilian tree Copaifera langsdorffii (copaiba), contain numerous hydrocarbon and selected chemical products which serve as potential renewable biocrude sources

    Anomalous transverse acoustic phonon broadening in the relaxor ferroelectric Pb(Mg_1/3Nb_2/3)O_3

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    The intrinsic linewidth Ī“TA\Gamma_{TA} of the transverse acoustic (TA) phonon observed in the relaxor ferroelectric compound Pb(Mg1/3_{1/3}Nb2/3)0.8_{2/3})_{0.8}Ti0.2_{0.2}O3_3 (PMN-20%PT) begins to broaden with decreasing temperature around 650 K, nearly 300 K above the ferroelectric transition temperature TcT_c (āˆ¼360\sim 360 K). We speculate that this anomalous behavior is directly related to the condensation of polarized, nanometer-sized, regions at the Burns temperature TdT_d. We also observe the ``waterfall'' anomaly previously seen in pure PMN, in which the transverse optic (TO) branch appears to drop precipitously into the TA branch at a finite momentum transfer qwfāˆ¼0.15q_{wf} \sim 0.15 \AAāˆ’1^{-1}. The waterfall feature is seen even at temperatures above TdT_d. This latter result suggests that the PNR exist as dynamic entities above TdT_d.Comment: 6 pages, 4 figure

    Gametophytic Selection in Arabidopsis thaliana Supports the Selective Model of Intron Length Reduction

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    Why do highly expressed genes have small introns? This is an important issue, not least because it provides a testing ground to compare selectionist and neutralist models of genome evolution. Some argue that small introns are selectively favoured to reduce the costs of transcription. Alternatively, large introns might permit complex regulation, not needed for highly expressed genes. This ā€œgenome designā€ hypothesis evokes a regionalized model of control of expression and hence can explain why intron size covaries with intergene distance, a feature also consistent with the hypothesis that highly expressed genes cluster in genomic regions with high deletion rates. As some genes are expressed in the haploid stage and hence subject to especially strong purifying selection, the evolution of genes in Arabidopsis provides a novel testing ground to discriminate between these possibilities. Importantly, controlling for expression level, genes that are expressed in pollen have shorter introns than genes that are expressed in the sporophyte. That genes flanking pollen-expressed genes have average-sized introns and intergene distances argues against regional mutational biases and genomic design. These observations thus support the view that selection for efficiency contributes to the reduction in intron length and provide the first report of a molecular signature of strong gametophytic selection

    Perceptual properties of feedback stimuli influence the feedbackā€related negativity in the flanker gambling task

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    A negative deflection in the eventā€related potential is enhanced following errorā€ and lossā€related feedback in decisionā€making and simple gambling tasks. Researchers have assumed that the perceptual properties of the feedback stimuli are unimportant in explaining these effects. This assumption was tested in the present study through a flanker gambling task, in which the perceptual properties of the feedback were manipulated. Consistent with previous studies, loss elicited a larger feedbackā€related negativity ( FRN ) than gain feedback. However, this FRN reward effect was modulated by the perceptual properties of the feedback stimuli. When gain and loss feedback were perceptually similar to each other, the enhancement of the FRN following the loss feedback was smaller compared to when the gain and loss feedback were different from each other. In addition, incongruent feedback elicited a larger FRN than congruent feedback; this FRN congruency effect was larger following gain than loss feedback. These results suggested that perceptual properties of the feedback stimuli play a role in the elicitation of the FRN .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108013/1/psyp12216.pd
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