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Can interface conditions be modified by support surfaces to minimise the risk of pressure ulcer development?
No full textPhDThe characteristics of a patient support interface can influence the susceptibility of subjects, particularly there who are immobilised and insensate, to pressure ulcer development. Accordingly, externally powered alternating pressure air mattresses (APAM) are utilised to produce intermittent pressure relief and control of the interface microclimate. These conditions will permit adequate blood and lymph flow within the soft tissues and favourable conditions at the loaded skin surface and thus minimise the risk of ulcer formation.
Two sets of measurements were performed. Tissue viability was estimated, from a measure of transcutaneous gas tensions and sweat content, from healthy volunteers subjected to various alternating pressure regimens. The latter was achieved by two different strategies a) a custom–made controller which imposes the pressure profile on the subject and b) a prototype APAMs incorporating a novel sensor, which adjusts the profile according to individual subject characteristics. The latter prototype was placed on an articulated hospital bed, with an adjustable Head of Bed (HOB) angle. The second set of measurements involved monitoring the microclimate, namely temperature and humidity, at the interface loaded with a human analogue model supported on an APAM system. The interface was saturated with moisture to simulate sweating.
The human studies, involving healthy subjects with BMI values ranging from 18.9 to 42.5 kg/m2, revealed significant differences in soft tissue response under various support surface profile by both strategies. In many cases, the TcPO2 levels either remained fairly stable during the loaded period or fluctuated at a periodicity equivalent to the cycle period of the APAM system, with the corresponding TcPCO2 levels remaining within the normal basal range. These findings were associated with
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maximum interface pressures generally not exceeding 50 mmHg (6.67 kPa). By contrast in some cases, there was a significant compromise to the TcPO2 levels during the loaded period, which was often associated with an increase in TcPCO2 levels. These cases generally corresponded with the internal pressures in the mattress prescribed at a maximum amplitude of 100 / 0 mmHg or when the Head of Bed angle was raised to 45º or above.
Changes in prototype covering sheet and air flow rates of the APAM system were found to influence both interface temperature and humidity. These results revealed enhanced levels of humidity often reaching 100% RH at the high simulated sweat rates. By contrast, at the lower sweat rate of 1.5 ml/min, the nature of the prototype covering sheets had an effect on the interface humidity profile, with values considerably reduced in the latter stages of the monitoring period. These results were compared with a compartmental model, which predicted the transport of moisture and heat using various mattress support systems.
The results offer the potential for the development of intelligent APAM systems, whose characteristics can be adjusted to an individual morphology. These systems will need to be designed to ensure adequate tissue viability and maintain appropriate microclimate at the loaded interface. Such an approach will be directed at those subjects considered to be at high/medium risk of developing pressure ulcers
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
The influence of fluid shear stress on the spatial organization of Notch/Jagged signalling in vascular cells
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