1,720,991 research outputs found
Distortion product otoacoustic emissions: challenging existing theory
No full textDistortion product otoacoustic emissions (DPOAE or DP) are generated using two primary tones at frequencies f1 and f2 at levels L1 and L2; the two most prominent DP are cubic distortion products at the frequencies 2f1f2 and 2f2f1. Current understanding of their origin indicates that they arise via two distinct mechanisms. One mechanism is thought to be non-linear distortion and the other linear coherent reflection. Recent investigations have confirmed that both components are present in the 2f2f1 DP, which conflicts with current understanding of the generation mechanisms, suggesting that the location of origin of the DP at 2f2f1 may be different from that at 2f1f2.Distortion and reflection components of DP combine in the cochlea. One method to separate them is time window separation, which utilises phase variation in the frequency domain to infer latency in the time domain, by means of inverse Fourier transformation. It is independent of the location of generation of the DP but depends on the generation mechanism. By contrast, DP can be reduced by the introduction of a third suppressor tone, which can be used to infer the location of DP generation based of the suppressor tone frequency, independent of generation mechanism.The aim of this investigation was to assess the effect of suppressor frequency and level on the 2f2f1 DP, in order to make inferences about where this DP originates. Twenty normally hearing participants took part in the investigation. DP were measured (L1 = 65, L2 = 55 dB SPL) with a fixed frequency ratio f2/f1 = 1.05. By sweeping the primary frequencies in the ranges f2 = 1.75-2.25 and 3.75-4.25 kHz, suitable fixed test frequencies were identified for subsequent suppression testing in each ear, as the frequencies giving DP with the greatest signal-to-noise ratio. The frequency sweeps also allowed analysis by time window separation. Suppression was carried out with suppressor levels introduced at 0, 20, 40 and 60 dB SPL. The frequency of the suppressor was altered from 32 Hz to +64 Hz relative to the DP, in 16 Hz increments.Results of time window separation confirmed that both non-linear distortion and reflection components were present in both the 2f2f2 DP and 2f2f1 DP. However, it was not possible to separate the two components of the 2f2f1 DP by suppression, which suggests that the 2f2f1 DP is not generated at a discrete place. It is concluded that the generation mechanism for the 2f2f1 DP may be distributed along the cochlear partition at or basal to the characteristic place corresponding to the DP frequency
International convention tourism: A choice modelling experiment of host city competition
No full textMany cities around the world today place considerable emphasis in their tourism strategies on enhancing their competitiveness as potential convention hosts. The objective of this research was to evaluate how site attributes affect the choice of a host city in the international conventions tourism market. The study employed discrete choice modelling using a stated choice approach and analysed data from a survey of international association convention planners. The results demonstrated that the top ten site attributes were (in descending order): the convenience of flight schedules; risk of disruption to the convention; inbound travel barriers or formalities; on-site vs. off-site delegate accommodation; number of available four star hotels; cost of the convention facility; possibility of a subsidy to defray costs; number of available five star hotels; whether or not the association held its convention at the site previously; and domestic air travel costs
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Time-Varying Effects of Empowerment on Job Satisfaction for Customer-Contact versus Non-Customer-Contact Employee Groups
No full textThis study investigates the relationship between employee empowerment and job satisfaction, and whether this relationship is stronger for customer-contact employees than their non-customer-contact counterparts. Further, using a growth curve modeling technique, it also examines, whether the relationship between empowerment and job satisfaction changes across time. Using a three year longitudinal dataset from a large hospitality company, the authors find that the effect of empowerment on job satisfaction is more salient for customer-contact employee groups, and the effect accelerates over time regardless of the nature of work. Theoretical and practical implications and recommendations for future research are discussed based on the results
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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
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