983 research outputs found

    Optical devices using an external cavity semiconductor laser

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    A dual-mode optical device selectively operative in signal generation and amplification modes is disclosed herein. The dual-mode device includes a body of semiconductor material having opposed from and rear facets. During operation in the amplification mode, light is input through the front facet and is amplified within the body of the optical gain material. An at least partially optically reflective surface is positioned a first predetermined distance from one of the facets during operation of the device in the amplification mode. In the signal generation mode, the at least partially optically reflective surface is positioned a second predetermined distance from the one facet so as to induce optical oscillation within the body of semiconductor material. In a preferred implementation, a semiconductor diode laser having opposed first and second facets is utilized as an optical source. An at least partially optically reflective surface is positioned a predetermined distance from one of the first and second facets in order that a resonant cavity is formed therebetween. The predetermined distance between the at least partially optically reflective surface and the one facet may be modulated, thereby allowing modulation of optical output produced by the semiconductor diode laser

    Developing a scale to measure problems in finding a good fit

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    The purpose of this study was to develop a scale for measuring perceived PFGF. This research conceptualized problems of finding a good fit (PFGF) as a consumer\u27s generalized perception of fit problems based on prior experience with physical, aesthetic, and functional aspects of clothing. Scale development took place through item generation, preliminary tests of reliability and validity, and final scale validation. This study contributes to the literature of consumer fit perceptions by developing a scale to assess perceived PFGF that may be a key factor influencing multiple apparel shopping behaviors, such as returning unsatisfactory products and online shopping conversion rate. The multidimensional scale of perceived PFGF should be useful to apparel product developers and designers by providing solutions to PFGF based on information from customers. Better understanding of perceived PFGF will ultimately increase consumer fit satisfaction

    Advances in the Understanding of the Genetic Determinants of Congenital Heart Disease and Their Impact on Clinical Outcomes

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143784/1/jah33022.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143784/2/jah33022_am.pd

    Resonant Photoemission in f-Electron Systems: Pu and Gd

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    Resonant photoemission in the Pu 5f and Pu 6p states is compared to that in the Gd 4f and Gd 5p states. Spectral simulations, based upon an atomic model with angular momentum coupling, are compared to the Gd and Pu results. Additional spectroscopic measurements of Pu, including core level photoemission and x-ray absorption, are also presented

    Cryptography for Parallel RAM from Indistinguishability Obfuscation

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    Since many cryptographic schemes are about performing computation on data, it is important to consider a computation model which captures the prominent features of modern system architecture. Parallel random access machine (PRAM) is such an abstraction which not only models multiprocessor platforms, but also new frameworks supporting massive parallel computation such as MapReduce. In this work, we explore the feasibility of designing cryptographic solutions for the PRAM model of computation to achieve security while leveraging the power of parallelism and random data access. We demonstrate asymptotically optimal solutions for a wide-range of cryptographic tasks based on indistinguishability obfuscation. In particular, we construct the first publicly verifiable delegation scheme with privacy in the persistent database setting, which allows a client to privately delegate both computation and data to a server with optimal efficiency. Specifically, the server can perform PRAM computation on private data with parallel efficiency preserved (up to poly-logarithmic overhead). Our results also cover succinct randomized encoding, searchable encryption, functional encryption, secure multiparty computation, and indistinguishability obfuscation for PRAM. We obtain our results in a modular way through a notion of computational-trace indistinguishability obfuscation (CiO), which may be of independent interests

    Glycosylation Is Vital for Industrial Performance of Hyperactive Cellulases

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    In the terrestrial biosphere, biomass deconstruction is conducted by microbes employing a variety of complementary strategies, many of which remain to be discovered. Moreover, the biofuels industry seeks more efficient (and less costly) cellulase formulations upon which to launch the nascent sustainable bioenergy economy. The glycan decoration of fungal cellulases has been shown to protect these enzymes from protease action and to enhance binding to cellulose. We show here that thermal tolerant bacterial cellulases are glycosylated as well, although the types and extents of decoration differ from their Eukaryotic counterparts. Our major findings are that glycosylation of CelA is uniform across its three linker peptides and composed of mainly galactose disaccharides (which is unique) and that this glycosylation dramatically impacts the hydrolysis of insoluble substrates, proteolytic and thermal stability, and substrate binding and changes the dynamics of the enzyme. This study suggests that the glycosylation of CelA is crucial for its exceptionally high cellulolytic activity on biomass and provides the robustness needed for this enzyme to function in harsh environments including industrial settings

    Deletion at ITPR1 Underlies Ataxia in Mice and Spinocerebellar Ataxia 15 in Humans

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    We observed a severe autosomal recessive movement disorder in mice used within our laboratory. We pursued a series of experiments to define the genetic lesion underlying this disorder and to identify a cognate disease in humans with mutation at the same locus. Through linkage and sequence analysis we show here that this disorder is caused by a homozygous in-frame 18-bp deletion in Itpr1 (Itpr1Δ18/Δ18), encoding inositol 1,4,5-triphosphate receptor 1. A previously reported spontaneous Itpr1 mutation in mice causes a phenotype identical to that observed here. In both models in-frame deletion within Itpr1 leads to a decrease in the normally high level of Itpr1 expression in cerebellar Purkinje cells. Spinocerebellar ataxia 15 (SCA15), a human autosomal dominant disorder, maps to the genomic region containing ITPR1; however, to date no causal mutations had been identified. Because ataxia is a prominent feature in Itpr1 mutant mice, we performed a series of experiments to test the hypothesis that mutation at ITPR1 may be the cause of SCA15. We show here that heterozygous deletion of the 5′ part of the ITPR1 gene, encompassing exons 1–10, 1–40, and 1–44 in three studied families, underlies SCA15 in humans
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