1,721,040 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Development of a parametric down-conversion source for two-photon absorption experiments
No full textWe describe a fiber-coupled parametric down-conversion (PDC) source designed for entanglement-enhanced twophoton absorption experiments. The key feature of the source is a narrowband (~1 MHz) UV diode pumping laser which can be tuned to match the energy of the 5S₁∕₂ to 5D₅∕₂ two-photon transition in Rubidium. The weak narrowband pumping beam is delivered to the PDC crystal through a single-mode fiber, which allows the source to be pre-aligned with a much stronger broadband auxiliary pump laser. The motivation for this PDC source lies within the context of Linear Optics Quantum Computing and Quantum Zeno Gates.The author gratefully acknowledges useful discussions with Jim Franson, Scott Hendrickson, and Bryan Jacobs. This work was supported in part by DTO-funded U.S. Army Research Office grant No. W911NF-05-1-0397.https://www.spiedigitallibrary.org/conference-proceedings-of-spie/6710/67100B/Development-of-a-parametric-down-conversion-source-for-two-photon/10.1117/12.734444.shor
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Experimental Storage of Entangled Photons in Broadband Loop-based Quantum Memories
No full textQuantum memories are a crucial component in the development of large-scale quantum networks, enabling the synchronization and storage of quantum states for long-distance communication and distributed quantum entanglement. This dissertation explores the experimental realization and characterization of broadband, loop-based quantum memories, with a particular emphasis on their ability to store and preserve entanglement. We present experimental investigations demonstrating the feasibility of these memories in various quantum information applications, including quantum networking and non-local phase correction.We present a detailed study of the key components of our memory system, including high-speed Pockels cells for active storage control, and optics components and their losses limiting maximum efficiencies. Additionally, we analyze alignment
conditions using Gaussian beam propagation techniques, ensuring optimal mode-matching for long-term storage stability.
Next, we experimentally demonstrate the storage of polarization-entangled photon pairs using a single active loop-based quantum memory in conjunction with a passive fiber delay line. By performing Bell tests before and after storage, we
confirm the preservation of entanglement across multiple storage cycles. This proof-of-concept experiment establishes the viability of loop-based memories for entanglement distribution and provides insights into efficiency limitations due to optical
losses.
Building upon this, we extend our system to incorporate two independently controlled active quantum memories, allowing for flexible and tunable storage of both photons of an entangled pair. This dual-memory configuration enables deeper exploration of entanglement storage, including the effects of differential storage times and non-local phase correction.
Our results validate the practicality of broadband, loop-based quantum memories as a versatile platform for quantum communication. This dissertation represents a significant step toward scalable quantum networking, demonstrating key
capabilities necessary for the deployment of high-performance quantum repeaters and entanglement-based communication protocols. The next logical progression involves expanding these experiments to incorporate additional quantum memories, enabling more complex entanglement distribution and multi-node quantum networks. Achieving this will require further technical advancements in the loop-based memory platform, including improved loss mitigation, enhanced phase stabilization, and the integration of additional control mechanisms for manipulating stored qubits. The techniques developed herein lay the groundwork for these future advances in memory-assisted quantum technologies
Ultralow-power nonlinear optics using optical nanofibers in metastable xenon
No full textNonlinear optics (NLO) is a very broad field with applications ranging from frequency conversion and all- optical switching to quantum computing. For many of these applications, the use of low power lasers is desirable. Consequently, there is currently a push for the realization of new physical platforms enabling ultralow-power NLO. Here I perform research on a promising new ultralow-power NLO platform consisting of an optical nanofiber (ONF) suspended in a gas of metastable xenon atoms (Xe*). The origin of the strong nonlinearity in this platform is due to the tight confinement of the ONF guided evanescent mode (~1 square ?m) over a long distance (~1 cm), and a resonant interaction of the mode with the surrounding atoms.This work focusses on the results of two key experimental studies using this ?ONF in Xe*? platform. In the first study, we investigate the transmission characteristics of ONF'ssurrounded with a xenon plasma produced by low-pressure inductive RF discharge. In contrast with related experiments using rubidium vapor, we find essentially no degradation of optical transmission through the ONF'sas a function of time. We also observe a pronounced ONF transmission modulation effect that depends on the conditions of the xenon plasma, and may have practical applications
The second study is motivated by the goal of producing high metastable state densities in the xenon gas surrounding the ONFs. Specifically, we investigate the physics required to promote a large fraction of the xenon atoms from the ground state to the metastable state using a recently proposed hybrid technique that combines RF discharge techniques with optical pumping from an auxiliary state in xenon. We study the effect of xenon pressure on establishing initial population in both the auxiliary state and metastable state via the RF discharge, and the role of the optical pumping beam power in transferring population between the states. We find experimental conditions that maximize the effects, and provide a robust platform for producing relatively large long-term metastable state densities. We expect these high Xe* densities to be a key enabling technology for ultralow-power NLO in the ?ONF in Xe*? platform
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