3,739 research outputs found

    An Analytical Framework for Making Sense of Students’ Graphical Representations with Attention to Frames of Reference and Coordinate Systems

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    Graph literacy, the ability to interpret and create graphical representations, is an important skill for students to learn mathematics and to succeed in STEM coursework and careers. Additionally, with the rapid development of technological devices and media, students are encountering increasingly more situations in which graph literacy is needed to make sense of and respond to information. In this paper, I present a conceptual analysis of what I consider the three layers constituting a graphical representation: frames of reference, coordinate system, and graph. Relatedly, I synthesize relevant literature and propose an analytical framework that could be used to make sense of students’ representations of spatial phenomena. The analytical framework was designed to answer the following question: How do students make sense of a spatial situation, establish frames of reference, and create re-presentations of the spatial situation via coordinated measurements? After I elaborate on the analytical framework, I draw data from teaching experiments to illustrate how the framework could be used to model students’ representations of spatial phenomena with attention to frames of reference and coordinate systems. Finally, I discuss how this framework could be used by researchers and educators for better attending to students’ graph thinking and making sense of students’ graph literacy

    North Korea\u27s Food Crisis and Refugees (2)

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    Conjugated polyelectrolytes: A new class of semiconducting material for organic electronic devices

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    AbstractThis feature article presents a short review of the recent developments in the synthesis of conjugated polyelectrolytes (CPEs) along with their applications in organic optoelectronic devices with particular focus on the molecular structures of CPEs with ionic functionality, synthetic approaches, and their utilization as an interfacial layer. The orthogonal solubility of the CPEs allows the simple preparation of multilayer organic devices by solution casting on top of a nonpolar organic photoactive layer without disturbing the interfaces, showing their effectiveness in tuning the electronic structures at the interfaces for improving the charge carrier transport and resulting device properties. These achievements highlight the dynamic nature of CPEs and their applicability to a wide range of optoelectronic devices

    ADADA 2016 14TH international Conference for Asia Digital Art and Design Association - Relationship between perceived value in Omni-Channel Shopping and repurchase intention

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    Along with the development of ICT, the distribution strategy of existing companies has been changing to the ‘Omni-Channel’ strategy. According to the diversification of distribution channels, the value of customer shopping has also been changing. Consumers that shop within various distribution channels want to acquire benefits through new and diversified experiences. Thus, it is important to perform studies on whether continuous purchase is possible by continuing from values that are being satisfied by certain elements of the Omni-Channel by grasping the cognition of consumers. This study identifies the characteristics of Omni-Channel consumption, perceived usefulness through the ease-of-use by consumers, and relationships with repurchase intention. This study provides a theoretical basis to activate the Omni-Channel which may satisfy the demand of consumers by setting causal relationship between each element by conducting a survey

    Beyond slurry-cast supercapacitor electrodes: PAN/MWNT heteromat-mediated ultrahigh capacitance electrode sheets

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    Supercapacitors (SCs) have garnered considerable attention as an appealing power source for forthcoming smart energy era. An ultimate challenge facing the SCs is the acquisition of higher energy density without impairing their other electrochemical properties. Herein, we demonstrate a new class of polyacrylonitrile (PAN)/multi-walled carbon tube (MWNT) heteromat-mediated ultrahigh capacitance electrode sheets as an unusual electrode architecture strategy to address the aforementioned issue. Vanadium pentoxide (V2O5) is chosen as a model electrode material to explore the feasibility of the suggested concept. The heteromat V2O5 electrode sheets are produced through one-pot fabrication based on concurrent electrospraying (for V2O5 precursor/MWNT) and electrospinning (for PAN nanofiber) followed by calcination, leading to compact packing of V2O5 materials in intimate contact with MWNTs and PAN nanofibers. As a consequence, the heteromat V2O5 electrode sheets offer three-dimensionally bicontinuous electron (arising from MWNT networks)/ion (from spatially reticulated interstitial voids to be filled with liquid electrolytes) conduction pathways, thereby facilitating redox reaction kinetics of V2O5 materials. In addition, elimination of heavy metallic foil current collectors, in combination with the dense packing of V2O5 materials, significantly increases (electrode sheet-based) specific capacitances far beyond those accessible with conventional slurry-cast electrodes.ope

    Full sequence analysis and characterization of the South Korean Norovirus GII-4 variant CUK-3

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    <p>Abstract</p> <p>Background</p> <p>Many of researchers have focused on the emerging pathogen, Norovirus, since its first identification as the causing agent of nonbacterial acute gastroenteritis in humans. One of the virulence factors of norovirus, the great genetic diversity attributed to point mutations and recombinations, has brought forth the result of significant changes in the circulating norovirus genotype patterns.</p> <p>Findings</p> <p>In recognition of the necessity for tracking and monitoring of genetic diversity, a norovirus variant among the most prevalent genotype GII-4, Norovirus Hu/GII-4/CUK-3/2008/KR (CUK-3), was isolated from stool samples and analyzed on the level of whole genome sequence. Whole genome sequence analysis revealed three ORF composites of the whole genome, ORF1 (5100 bp), ORF2 (1623 bp), and ORF3 (807 bp). Each genetic relationship of CUK-3 variant analysis located the ORF1 (5,100 bp) in Cluster I, ORF2 (1623 bp) in Cluster I (2006b), ORF3 (807 bp) in Cluster I, and the whole genome sequence (about 5.1 kb) in Cluster I in the phylogenetic tree. And the phylogenetic analyses showed the same location of CUK-3 strain with the GII-4/2006b cluster in the phylogenetic tree.</p> <p>Conclusions</p> <p>In This study, a first concerning the full-length sequence of a NoV variant in South Korea is meaningful in that it can be used not only as a full-length NoV variant sequence standard for future comparison studies, but also as useful material for the public health field by enabling the diagnosis, vaccine development, and prediction of new emerging variants.</p

    Effects of strobe light stimulation on postnatal developing rat retina

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    The nature and intensity of visual stimuli have changed in recent years because of television and other dynamic light sources. Although light stimuli accompanied by contrast and strength changes are thought to have an influence on visual system development, little information is available on the effects of dynamic light stimuli such as a strobe light on visual system development. Thus, this study was designed to evaluate changes caused by dynamic light stimuli during retinal development. This study used 80 Sprague-Dawley rats. From eye opening (postnatal day 14), half of the rats were maintained on a daily 12-h light/dark cycle (control group) and the remaining animals were raised under a 12-h strobe light (2 Hz)/dark cycle (strobe light-reared group). Morphological analyses and electroretinogram (ERG) were performed at postnatal weeks 3, 4, 6, 8, and 10. Among retinal neurons, tyrosine hydroxylase-immunoreactive (TH-IR, dopaminergic amacrine cells) cells showed marked plastic changes, such as variations in numbers and soma sizes. In whole-mount preparations at 6, 8, and 10 weeks, type I TH-IR cells showed a decreased number and larger somata, while type II TH-IR cells showed an increased number in strobe-reared animals. Functional assessment by scotopic ERG showed that a-wave and b-wave amplitudes increased at 6 and 8 weeks in strobe-reared animals. These results show that exposure to a strobe light during development causes changes in TH-IR cell number and morphology, leading to a disturbance in normal visual functions
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