2,534 research outputs found

    A functional identity involving elliptic integrals

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    Producción CientíficaWe show that adouble integral remains invariant as one trades some parameters. This invariance property is suggested from symmetry considerations in the operating characterstics of a semiconductor Hall-effect device.Ministerio de Economía, Industria y Competitividad (project MTM2014-57129-C2-1-P)Junta de Castilla y Leon (project UIC 0 11

    Symmetries of certain double integrals related to Hall effect devices

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    Producción CientíficaOne encounters iterated elliptic integrals in the study of Hall effect devices, as a result of conformal mappings of Schwarz–Christoffel type. Some of these double elliptic integrals possess amazing symmetries with regard to the physical parameters of the underlying Hall effect devices. We give a unified mathematical treatment of such symmetric double integrals, in the context of Hall effect devices with three and four contacts.Junta de Castilla y León (VA057U16) and MINECO (Project MTM2014-57129-C2-1-P)

    A self-regulated learning approach to extensive listening and its impact on listening achievement and metacognitive awareness

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    The role of self-regulation in general learning has been investigated for some time now. Its significance and contribution to second language (L2) listening, however, has yet to be discussed extensively with empirical support. This article reports a case study involving four college EFL students in China over a six-month period of self-regulated learning (SRL) in developing their listening in independent settings. The study examined how the achievement and metacognitive awareness of four high-achieving and low-achieving listeners may have been affected by strategies they used for self-regulating extensive listening activities. It also examined the learners’ engagement during four phases of self-regulated listening, namely, task definition, goal setting and planning, strategy enactment, and metacognitive adaptation. Findings revealed substantial differences in the two groups’ metacognitive engagement in three SRL phases. The article argues that the achievements of the respective learners in listening development were affected by these differences. Pedagogical implications of a self-regulated learning approach in extensive listening for L2 listening development are discussed

    Comparative Studies between the Regional Economic Growth Levels Based on the Three-Stage Weight Dynamic Comprehensive Evaluation

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    Part 5: Modelling and SimulationInternational audienceThis paper proposes a dynamic comprehensive evaluation method based on three times weight. Firstly, this paper determines the index weight based on the twice stage difference driving features. Then it introduces the relative balance coefficient to calculate the comprehensive evaluation value. This method has the following characteristics: 1) The comprehensive evaluation result is totally based on the information provided by the evaluating indicator system, without the influence from subjective factors; 2) The results have direct comparability among different evaluation systems at each time; 3) Motivation or punishment are the characteristics of this method. This approach has been applied to an empirical study of the regional economic growth level during the years of 2001 and 2011. Finally this paper makes related suggestions to the economic development of eight domestic economic regions

    Unusually Large Deuterium Discrimination during Spore Photoproduct Formation

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    The deuterium-labeling strategy has been widely used and proved highly effective in mechanistic investigation of chemical and biochemical reactions. However, it is often hampered by the incomplete label transfer, which subsequently obscures the mechanistic conclusion. During the study of photoinduced generation of 5-thyminyl-5,6-dihydrothymine, which is commonly called the spore photoproduct (SP), the Cadet laboratory found an incomplete (∼67%) deuterium transfer in SP formation, which contrasts to the exclusive transfer observed by the Li laboratory. Here, we investigated this discrepancy by re-examining the SP formation using d3-thymidine. We spiked the d3-thymidine with varying amounts of unlabeled thymidine before the SP photochemistry is performed. Strikingly, our data show that the reaction is highly sensitive to the trace protiated thymidine in the starting material. As many as 17-fold enrichment is detected in the formed SP, which may explain the previously observed one-third protium incorporation. Although commercially available deuterated reagents are generally satisfactory as mechanistic probes, our results argue that attention is still needed to the possible interference from the trace protiated impurity, especially when the reaction yield is low and large isotopic discrimination is involved

    Physiological and Molecular Characterisation of Lucerne (Medicago sativa L.) Germplasm with Improved Seedling Freezing Tolerance

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    We conducted greenhouse experiments to compare 14 lucerne (alfalfa, Medicago sativa L.) germplasms for their survival following freezing. Some are collections adapted to the Grand River National Grasslands in South Dakota. We hypothesised that these collections might have developed a tolerance to survive the frigid growth conditions common there. Two of these collections, River side (RS) and Foster ranch (FR), showed greater freezing tolerance than the other germplasms tested, based on their consistent survival rates with or without cold acclimation. In multiple freezing studies, RS and FR had average survival rates of 74% and 79%, respectively, in contrast to the commercial cultivars Apica and CUF-101 (CUF) (64% and 24%, respectively). The average temperature at which 50% of ions in plant tissues leak out (LT50) by freezing based on leaf electrolyte leakage was closely correlated with survival rates. Leaf LT50 improved 2–3-fold after 3 days of cold acclimation, based on leaf electrolyte leakage analysis, reaching −18°C, –9.6°C, –8.5°C, and −5°C for RS, FR, Apica, and CUF, respectively. Comparison of total soluble sugars and relative water content in shoots before and after cold acclimation showed that they were not well correlated with freezing tolerance and could not explain the superior responses of RS and FR during cold acclimation. Transcript analysis of cold-responsive MsCBF1, MsCBF2 and CAS15B genes showed that RS, FR, Apica and CUF exhibited distinct patterns of cold induction. Although RS, FR and Apica showed a rapid or greater increase in expression level of one or two of these genes, CUF showed only a moderate induction in MsCBF2 and CAS15B transcripts, suggesting that expression of these genes may be a good molecular marker for freezing tolerance in lucerne. The findings provide evidence that freezing tolerance in lucerne is a complex trait and that a combination of different mechanisms may greatly improve freezing tolerance. RS and FR are potential resources in breeding for improving freezing tolerance in lucerne

    l-Dopa induced dyskinesias in Parkinsonian mice: Disease severity or l-Dopa history

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    AbstractIn Parkinson’s disease, the efficacy of l-Dopa treatment changes over time, as dyskinesias emerge with previously beneficial doses. Using MitoPark mice, that models mitochondrial failure in dopamine (DA) neurons and mimics the progressive loss of dopamine observed in Parkinson’s disease, we found that the severity of DA denervation and associated adaptations in striatal neurotransmission at the time of initiation of l-Dopa treatment determines development of l-Dopa induced dyskinesias. We treated 20-week, and 28-week old MitoPark mice with l-Dopa (10mg/kg i.p. twice a day) and found locomotor responses to be significantly different. While all MitoPark mice developed sensitization to l-Dopa treatment over time, 28-week old MitoPark mice with extensive striatal DA denervation developed abnormal involuntary movements rapidly and severely after starting l-Dopa treatment, as compared to a more gradual escalation of movements in 20-week old animals that started treatment at earlier stages of degeneration. Our data support that it is the extent of loss of DA innervation that determines how soon motor complications develop with l-Dopa treatment. Gene array studies of striatal neurotransmitter receptors revealed changes in mRNA expression levels for DA, serotonin, glutamate and GABA receptors in striatum of 28-week old MitoPark mice. Our results support that delaying l-Dopa treatment until Parkinson’s disease symptoms become more severe does not delay the development of l-Dopa-induced dyskinesias. MitoPark mice model genetic alterations known to impair mitochondrial function in a subgroup of Parkinson patients and provide a platform in which to study treatments to minimize the development of dyskinesia

    Extra Large G-Protein Interactome Reveals Multiple Stress Response Function and Partner-Dependent XLG Subcellular Localization

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    The three-member family of Arabidopsis extra-large G proteins (XLG1-3) defines the prototype of an atypical Gα subunit in the heterotrimeric G protein complex. Recent evidence indicate that XLG subunits operate along with its Gβγ dimer in root morphology, stress responsiveness, and cytokinin induced development, however downstream targets of activated XLG proteins in the stress pathways are rarely known. To assemble a set of candidate XLG-targeted proteins, a yeast two-hybrid complementation-based screen was performed using XLG protein baits to query interactions between XLG and partner protein found in glucose-treated seedlings, roots, and Arabidopsis cells in culture. Seventy two interactors were identified and >60% of a test set displayed in vivo interaction with XLG proteins. Gene co-expression analysis shows that >70% of the interactors are positively correlated with the corresponding XLG partners. Gene Ontology enrichment for all the candidates indicates stress responses and posits a molecular mechanism involving a specific set of transcription factor partners to XLG. Genes encoding two of these transcription factors, SZF1 and 2, require XLG proteins for full NaCl-induced expression. The subcellular localization of the XLG proteins in the nucleus, endosome, and plasma membrane is dependent on the specific interacting partner
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