1,720,967 research outputs found
Benefits of helmet-mounted display image stabilisation under whole-body vibration
No full textThe effects of whole-body vertical vibration in the range 2.5-25 Hz on visual performance with two types of raster scan helmet-mounted display have been determined. The benefit of an image stabilisation system on numeral reading performance during vibration was also assessed with both display systems. Increases in mean reading time of over 130%/m . s-2 R.M.S. and increases in percentage reading error of more than 30%/m . s-2 R.M.S. were recorded with unstabilised displays. With vertical and horizontal image stabilisation, these decrements in performance were reduced to less than 40%/m . s-2 R.M.S. increase in reading time and less than 10%/m . s-2 R.M.S. increase in reading error. Data on the transmission of vibration from the seat to the head and from the head to the helmet were also obtained. These indicate a relation between biodynamic behaviour and visual performance during vibration
The ventilation cycle in Octopus
No full textPressure measurements made at various points inside the mantle show that the ventilatory stream of the resting animal is driven by very small (often less than 0.5 cm H2O) pressure differences. Inspiration occupies less than one third of the total cycle time, while flow across the gills is evidently continuous, since there is always a pressure differential between the prebranchial and postbranchial parts of the mantle cavity. The fact that branchial heartbeats do not correlate with ventilatory movements is further evidence that water flow through to the gills is both steady and continuous. <br/
Flight trial of a helmet-mounted display image stabilisation system
No full text An image stabilisation system for improving reading performance with a helmet-mounted display (HMD) during wholebody vibration was tested at night in a helicopter. Six subjects read arrays of 50 numerals as quickly and as accurately as possible while flying in three different flight controls. The mean reading time for each array while stationary on the ground was approximately 21 s, and the mean reading error was 0.4% without stabilisation. In-flight mean reading time increased to approximately 40 s, and reading error was 18% without the stabilisation system. Stabilising the image significantly reduced the mean in-flight time to approximately 25 s with a 4% reading error. Data from the flight trial support the results of previous experiments, which suggest that HMD reading performance with vibration and night viewing conditions may be inferior to performance with daylight conditions.</p
Short Communication: Continuous Recording of Arterial Blood PO2 in Octopus Vulgaris During Progressive Hypoxia and Movement
No full textThe effect of caffeinated versus decaffeinated drinks on overactive bladder: a double-blind, randomized, crossover study
No full textPurpose: the primary aims of this study were to test the methodology for use in a future randomized control trial and to investigate the effect of drinking caffeinated versus decaffeinated fluids on symptoms of overactive bladder (OAB) in women.Design: a double-blind, randomized, crossover study was conducted.Methods: fourteen community-dwelling women newly diagnosed with OAB and a history of caffeine consumption were randomly allocated to group A (14-day caffeinated drink period followed by 14-day decaffeinated drink period) or group B (14-day decaffeinated drink period followed by 14-day caffeinated drink period). The periods were preceded by a 14-day run-in period and interspersed with a 14-day washout period. Primary outcomes were episodes of urgency, frequency, volume per void, and incontinence obtained each period on 3-day bladder diaries. Secondary outcome measures were OAB symptom severity and health-related quality of life (QOL) recorded each period using International Consultation on Incontinence–Overactive Bladder Module (ICIQ-OAB) and ICIQ-OAB–Quality of Life (ICIQ-OABqol) tools. Effects of caffeine reduction were measured each day using visual analogue scales.Results: eleven participants completed the study. A significant reduction in urgency (P < .01) and frequency (P < .05) of urinary voids on day 3 of the diary, total ICIQ-OAB score (P < .01), and a non-significant directional change for the total ICIQ-OABqol score (P = .065) was found using sign tests for the period of decaffeinated compared to caffeinated drink intake. No significant differences were found for any caffeine withdrawal measures.Conclusions: despite the small sample size, this pilot study demonstrated that reducing caffeine intake may alleviate the severity of some symptoms and health-related QOL factors associated with OAB. Furthermore, caffeine substitutes were well tolerate
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
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