415 research outputs found

    A Scalable Architecture for Electronic Payments

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    We present a scalable architecture for electronic retail payments via central bank digital currency and offer a solution to the perceived conflict between robust regulatory oversight and consumer affordances such as privacy and control. Our architecture combines existing work in payment systems and digital currency with a new approach to digital asset design for managing unforgeable, stateful, and oblivious assets without relying on either a central authority or a monolithic consensus system. Regulated financial institutions have a role in every transaction, and the consumer affordances are achieved through the use of non-custodial wallets that unlink the sender from the recipient in the transaction channel. This approach is fully compatible with the existing two-tiered banking system and can complement and extend the roles of existing money services businesses and asset custodians.Comment: 24 pages, 7 figures, 2 table

    Work-Integrated and Cooperative Learning Effects on Micro-Electronics Design Classes

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    Cooperative learning and work-integrated learning are the latest trends in information delivery at high schools and universities. In cooperative learning, teachers organize students' interactions and educate them to work in small groups to enhance each other's learning. Whereas, work-integrated learning, is a type of experiential learning that allows students to participate in real-world work during their studies. Both approaches help bridge the gap between theoretical knowledge gained from classrooms and professional market needs. Electrical engineering is a field that could highly benefit from such a scheme. Having to be continuously up-to-date with the latest advances in the field of micro-electronics is difficult. Consequently, Several challenges are imposed on faculty members and academics who teach micro-electronics circuit design courses in electrical engineering for senior undergraduate or graduate students. This paper presents a case study of the apparent benefits and effectiveness of cooperative learning and work-integrated learning in the Electronics II and VLSI classes offered at a university. Furthermore, it aids programs in electrical engineering to meet ABET students' outcome (4)

    Exploring vibrational ladder climbing in vibronic coupling models: Toward experimental observation of a geometric phase signature of a conical intersection

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    Conical intersections (CIs) have been widely studied using spectroscopic techniques. However, CIs have mainly been identified by rapid internal conversion transitions that take place after the photoexcitation. Such identifications cannot distinguish various types of intersections as well as to separate the actual intersection from an avoided crossing. In this paper, we investigate how ultrafast IR laser pulses can be utilized to stimulate nuclear dynamics revealing geometric phase features associated with CIs. We consider two low-dimensional nonadiabatic models to obtain optimal two- and three-pulse laser sequences for stimulating nuclear dynamics necessary for the CI identification. Our results provide insights on designing non-linear spectroscopic schemes for subsequent probes of the nuclear wavepackets by ultrafast electron diffraction techniques to unambiguously detect CIs in molecules

    Novel applications of Generative Adversarial Networks (GANs) and Convolutional Neural Networks (CNNs) in the analysis of ultrafast electron diffraction (UED) images

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    We employ generative adversarial networks (GANs) and convolutional neural networks (CNNs) in the study of ultrafast electron diffraction images. We propose a machine learning approach that employs a GAN to convert experimental images into idealized diffraction patterns from which information is extracted via a CNN trained on synthetic data only. We validate this approach on ultrafast electron diffraction (UED) data of bismuth samples undergoing thermalization upon excitation via 800 nm laser pulses. The network was able to predict transient temperatures with a deviation of less than 6% from analytically estimated values. Notably, this performance was achieved on a dataset of 408 images only. We believe employing this network in experimental settings where high volumes of visual data are collected, such as beam lines, could provide insights into the structural dynamics of different samples

    Surgical management of ductal carcinoma in situ of the breast: A large retrospective study from a single institution

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    Background: Management of breast ductal carcinoma in situ (DCIS) has various approaches with distinct institutional specific practice. Here, we review DCIS management in a single institution with emphasise on re-operation rates and outcome. Methods: DCIS cases diagnosed at the Nottingham Breast Institute between 1987 and 2017 were identified (n=1,249). Clinicopathological data was collected. Cases were histologically reviewed, and different factors associated with primary operation selection, re-excision, presence of residual tumour in the re-excision specimens, use of radiotherapy and ipsilateral recurrences were analysed. Results: 34% of DCIS patients were initially treated by mastectomy and were more frequently symptomatic, of high nuclear tumour grade, size >40mm, and associated with comedo necrosis and Paget’s disease of the nipple. Further surgery was due to involved or narrow surgical margins. Residual tumour tissue was detected in 53% of the re-excision specimens. Re-excision rates of patients treated with breast conserving surgery (BCS) were reduced from approximately 70% to 23% and the final mastectomy rates decreased from 60% to 20%. Changes in surgical practice with acceptance of smaller excision margins and more frequent use of local radiotherapy have led to a significant decrease not only in the re-excision rate but also in the final mastectomy rate together with non-significant reduction in 5- and 10-year local recurrence rates. Conclusion: Although BCS is increasingly the preferred primary surgical option for DCIS management, a proportion of low-risk DCIS patients continue to undergo re-excision surgery or completion mastectomy. Despite acceptance of smaller margins, recurrence rate is decreasing

    4-(4,5-Diphenyl-1H-imidazole-2-yl)-N,N-dimethylaniline-Cu(II) complex, a highly selective probe for glutathione sensing in water-acetonitrile mixtures

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    The imidazole derivative 4-(4,5-diphenyl-1H-imidazol-2-yl)-N,N-dimethylaniline (probe 1) formed a highly coloured and non-emissive 1:1 stoichiometry complex with Cu(II) in water-acetonitrile 1:1 (v/v) solutions. Among all the amino acids (Lys, Val, Gln, Leu, His, Thr, Trp, Gly, Phe, Arg, Ile, Met, Ser, Ala, Pro, Tyr, Gly, Asn, Asp, Glu, Cys and Hcy) and tripeptides (GSH) tested, only GSH induced the bleaching of the 1·Cu(II) solution together with a marked emission enhancement at 411 nm (excitation at 320 nm). These chromo-fluorogenic changes were ascribed to a selective GSH-induced demetallation of the 1·Cu(II) complex that resulted in a recovery of the spectroscopic features of probe 1. In addition to the remarkable selectivity of 1·Cu(II) complex toward GSH a competitive limit of detection as low as 2 μM was determined using fluorescence measurements.We thank the Spanish Government (MAT2015-64139-C4-1-R) and Generalitat Valenciana (PROMETEOII/2014/047). H. E. O. thanks Generalitat Valenciana for his Grisolia fellowship. Thanks are also due to Fundação para a Ciência e Tecnologia (Portugal) for financial support to the Portuguese NMR network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDEReCOMPETEQREN-EU for financial support to the research centre CQUM (UID/QUI/0686/2016) and a doctoral grant to R.C.M. Ferreira (SFRH/BD/86408/2012). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC).info:eu-repo/semantics/publishedVersio
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