1,720,994 research outputs found
On-demand polarization by a vertical-cavity surface-emitting laser with two tilted sub-wavelength gratings
Full text linkWe show that each polarization state on the Poincaré sphere (PS) can be accessed on-demand (Poincaré sphere tailoring) by a semiconductor-based vertical-cavity surface-emitting laser (VCSEL) with two tilted sub-wavelength gratings (SWGs). We develop a vectorial Barkhausen criterion that answers the question: what conditions must the cavity fulfill to support a given desired polarization state? Addressing this inquiry leads to a completely different strategy based on the entangled interplay between two tilted SWGs, resulting in an overall chiral cavity, whose features depend on the gratings and their mutual rotation. This leads to the emission of a well-controllable polarization state based on standard technologies used in polarization-stable VCSELs, which paves the way for inspiring several new potential applications
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
Joint Experimental and Theoretical Investigations of Two-State Mode Locking in a Strongly Chirped Reverse-Biased Monolithic Quantum Dot Laser
No full textThe influence of different biasing conditions of a passively mode-locked strongly chirped two-section quantum-dot laser on its ground state (GS) and excited state (ES) emission is investigated both experimentally and theoretically. Numerical simulations performed with a modified time-domain travellingwave model are in qualitative agreement with experimental results and allow to identify the origin of the experimentally observed mode-locking regimes: the complex time-dependent coupling between the ES and GS absorption bleaching in the
saturable absorber section. This coupling, together with the difference in group velocities of ES and GS pulses, is found to be responsible for low-frequency inter-modulation signatures as observed experimentally and verified in the simulations
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
Extended ground-state and excited-state emission-state control in a mode-locked two-section quantum dot laser
No full textIn this paper, state-of-the-art research on two-state passive mode-locking of InAs/(In)GaAs quantum dot lasers is reviewed with a focus on the influence of extended absorber biasing conditions on the two quantized emission-states of a strongly inhomogeneously broadened quantum dot laser. We start with the recently demonstrated state-selectivity of ground-state, joint ground- and excited-state and then sole excited-state emission by a resistor Self-Electro-Optical Effect configuration. This regime is then extended towards the reverse-bias regime giving access to both excited-state and joint ground- and excited-state emission and to higher laser output power. Finally, we find an excellent accordance of the emission-states at the boundary of the two regimes. The occurrence and evolution of the emission-states in dependence on the biasing conditions are explained qualitatively
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