30,709 research outputs found

    Intraocular Pressure Fluctuation: Is It Important?

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    Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of glaucoma. Previous prospective, randomized, long-term studies have demonstrated the strength of IOP reduction in slowing the progression of disease. It is well known that IOP is not a fixed value but fluctuates considerably over time. Although there have been some studies on IOP fluctuation and the progression of glaucoma, whether IOP fluctuation is an independent risk factor for glaucomatous damage and disease progression remains controversial. In this article, we reviewed the definition of IOP fluctuation, and both the evidence and the speculation for and against the effect of IOP fluctuation on glaucoma progression. Although conclusions seem to vary from study to study, we considered that different studies examined different groups of patients, at different stages of disease, and at different IOP levels. Our conclusion is that these apparently disparate results are not conflicting, but rather can be viewed as complementary. In clinical care, we recommend the consideration of IOP "modulation" rather than just IOP "reduction" when glaucoma patients are treated. Quality-based IOP control may be more effective than quantity-based IOP reduction to prevent or retard disease progression

    Optimal Efficiency of Self-Assembling Light-Harvesting Arrays

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    Using a classical master equation that describes energy transfer over a given lattice, we explore how energy transfer efficiency along with the photon capturing ability depends on network connectivity, on transfer rates, and on volume fractions - the numbers and relative ratio of fluorescence chromophore components, e.g., donor (D), acceptor (A), and bridge (B) chromophores. For a one-dimensional AD array, the exact analytical expression for efficiency shows a steep increase with a D-to-A transfer rate when a spontaneous decay is sufficiently slow. This result implies that the introduction of B chromophores can be a useful method for improving efficiency for a two-component AD system with inefficient D-to-A transfer and slow spontaneous decay. Analysis of this one-dimensional system can be extended to higher-dimensional systems with chromophores arranged in structures such as a helical or stacked-disk rod, which models the self-assembling monomers of the tobacco mosaic virus coat protein. For the stacked-disk rod, we observe the following: (1) With spacings between sites fixed, a staggered conformation is more efficient than an eclipsed conformation. (2) For a given ratio of A and D chromophores, the uniform distribution of acceptors that minimizes the mean first passage time to acceptors is a key point to designing the optimal network for a donor-acceptor system with a relatively small D-to-A transfer rate. (3) For a three-component ABD system with a large B-to-A transfer rate, a key design strategy is to increase the number of the pathways in accordance with the directional energy flow from D to B to A chromophores.Comment: 9 pages, 6 figure

    A STUDY OF LUDWIG VAN BEETHOVEN’S PIANO SONATA OP. 111, ROBERT SCHUMANN’S OP.6 AND MAURICE RAVEL’S JEUX D’EAU

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    This research paper examines the following repertoire: Jeux d\u27eau by Maurice Ravel, Davidsbündertänze, Opus 6, by Robert Schumann, and Piano Sonata in C minor, Opus 111, by Ludwig van Beethoven. The purpose of this paper is to enhance performers’ understanding and performance of these pieces. By analyzing these works, this paper suggests that the performer delve more deeply into the structure and meaning behind this repertoire

    Measuring Willingness to Accept for GM Food by Characteristics

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    Korean consumers' willingness to accept (WTA) for GM food are studied in this paper. This study compares hypothetical and nonhypothetical responses to choice experiment questions. We test for hypothetical bias in a choice experiment involving GM rice with differing characteristic attributes and multinomial logit model is applied to predict the estimated results. In general, hypothetical responses predicted higher probabilities of purchasing GM rice than nonhypothetical responses. Thus, hypothetical choices overestimate willingness to accept for GM rice. The results of this paper could contributes to government's GM food policies and subsequent studies, also improving economic welfare of farmers and consumers.GM Food, Willingness to Accept, Choice experiment, Hypothetical bias, Food Consumption/Nutrition/Food Safety,

    Competing Magnetic Orderings and Tunable Topological States in Two-Dimensional Hexagonal Organometallic Lattices

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    The exploration of topological states is of significant fundamental and practical importance in contemporary condensed matter physics, for which the extension to two-dimensional (2D) organometallic systems is particularly attractive. Using first-principles calculations, we show that a 2D hexagonal triphenyl-lead lattice composed of only main group elements is susceptible to a magnetic instability, characterized by a considerably more stable antiferromagnetic (AFM) insulating state rather than the topologically nontrivial quantum spin Hall state proposed recently. Even though this AFM phase is topologically trivial, it possesses an intricate emergent degree of freedom, defined by the product of spin and valley indices, leading to Berry curvature-induced spin and valley currents under electron or hole doping. Furthermore, such a trivial band insulator can be tuned into a topologically nontrivial matter by the application of an out-of-plane electric field, which destroys the AFM order, favoring instead ferrimagnetic spin ordering and a quantum anomalous Hall state with a non-zero topological invariant. These findings further enrich our understanding of 2D hexagonal organometallic lattices for potential applications in spintronics and valleytronics.Comment: 9 pages, 8 figure

    General music teachers' practices of cooperative learning in two elementary music classrooms

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    The purpose of the study was to examine general music teachers’ practices of cooperative learning in two elementary music classrooms. Using the intrinsic case study method, I examined elementary general music teachers’ perspectives on cooperative learning, the utilization of cooperative learning in their general music classrooms, and the challenges the music educators faced in creating and implementing cooperative learning. I selected one general music classroom in two elementary schools in Boston, Massachusetts—totaling two general music teachers from different schools. I conducted eight class observations and three interviews for each participant during the fall 2016 semester. From separate and cross-case analyses, I found the following: (1) the two teachers’ instructions were linked to the characteristics of cooperative learning, (2) they believed that cooperative learning provided opportunities to improve students’ academic development in music and promote positive interpersonal relationships, and (3) both teachers used their own strategies for cooperative learning in order to maximize students’ learning. These findings provided evidence that cooperative learning engaged students in the process of learning music and, in addition, fostered positive interpersonal relationships. Moreover, this study suggested that music educators might undertake an effort to thoroughly understand students’ cognitive development when they wish utilize cooperative learning. Although this study was subject to a number of limitations due to its scope, the findings may contribute to the body of research on cooperative learning in elementary music education
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