Investigating the role of capacitive coupling between the operating table and the return electrode of an electrosurgery unit in the modification of the current density distribution within the patients’ body

Background: Electrosurgery units are widely employed in modern surgery. Advances in technology have enhanced the safety of these devices, nevertheless, accidental burns are still regularly reported. This study focuses on possible causes of sacral burns as complication of the use of electrosurgery. Burns are caused by local densifications of the current, but the actual pathway of current within patient's body is unknown. Numerical electromagnetic analysis can help in understanding the issue. Methods: To this aim, an accurate heterogeneous model of human body (including seventy-seven different tissues), electrosurgery electrodes, operating table and mattress was build to resemble a typical surgery condition. The patient lays supine on the mattress with the active electrode placed onto the thorax and the return electrode on his back. Common operating frequencies of electrosurgery units were considered. Finite Difference Time Domain electromagnetic analysis was carried out to compute the spatial distribution of current density within the patient's body. A differential analysis by changing the electrical properties of the operating table from a conductor to an insulator was also performed. Results: Results revealed that distributed capacitive coupling between patient body and the conductive operating table offers an alternative path to the electrosurgery current. The patient's anatomy, the positioning and the different electromagnetic properties of tissues promote a densification of the current at the head and sacral region. In particular, high values of current density were located behind the sacral bone and beneath the skin. This did not occur in the case of non-conductive operating table. Conclusion: Results of the simulation highlight the role played from capacitive couplings between the return electrode and the conductive operating table. The concentration of current density may result in an undesired rise in temperature, originating burns in body region far from the electrodes. This outcome is concordant with the type of surgery-related sacral burns reported in literature. Such burns cannot be immediately detected after surgery, but appear later and can be confused with bedsores. In addition, the dosimetric analysis suggests that reducing the capacity coupling between the return electrode and the operating table can decrease or avoid this problem. © 2013 Bifulco et al.; licensee BioMed Central Ltd.

modern foreign languages classroom:is inclusion of all exclusion in disguise?

The past decade has seen a drive to give all pupils the opportunity to study a Modern Foreign Language (MFL) in schools in England, making the teaching and learning of foreign languages part of the primary school curriculum. The Languages for All: Languages for Life (DfES, 2002) policy was introduced through the National Languages Strategy with an objective to increase the nation’s language capability. Raising the educational standard for all pupils is another government initiative with a strong emphasis on inclusion. As the Languages for All policy stresses the importance and benefits of language learning, and inclusion suggests equality and provision for all, this study examines the inclusion of all key stage 2 pupils in foreign language learning and describes perceptions and experiences of pupils, particularly those identified as having special educational needs (SEN) in their performances and negotiations in learning French. As a small scale, qualitative and ethnographically informed, this research is based on participant observation and semi-structured interviews with pupils, teachers of French, teaching assistants and parents. This study draws upon Nussbaum’s capabilities approach and Bourdieu’s concepts as theoretical foundations to analyse the ‘inclusive’ French classroom. As the capabilities approach takes people as ends not means, and goes beyond a focus on resources, it lends itself to critical thinking on issues around inclusion in education. In this context, this researcher investigates the experiences of pupils who struggle with foreign language learning because of their abilities or disabilities, and frames the discussion around the capabilities approach. The study also focuses on motivation and identity in foreign language learning, and draws upon Bourdieu’s concepts of capital, habitus and field to analyse how the participants make sense of and respond to their own circumstances in relation to their performances in the language learning process. This research thus considers Bourdieu’s concepts for a deeper understanding of issues of inequality in learning French and takes up Nussbaum’s insight that pupils may differ in what learning French means to them, and it is not how they differ, but the difference between their capability to choose and achieve what they value that should matter. The findings indicate that although, initially, the French classroom appears ‘inclusive’ due to the provision and practices of inclusion, a closer look shows it to be exclusionary. In addition, responses from the participants on the usefulness and benefits of foreign language learning are contradictory to the objectives of the Languages for All policy, illustrating the complexity of the ‘inclusive’ MFL classroom. This research concludes that structural and interpersonal practices of inclusion contribute to the disguising of exclusion in a classroom deemed ‘inclusive’. Implications are that an understanding and consideration of other aspect of life such as well-being, interests, needs and values should form a necessary part of the language policy.

Revisiting the lean agile paradigm:an empirical study in the aerospace industry

Much has been written about the potential impact of Lean Agile paradigm on firm's supply chain performance. However, most of the existing studies mainly pointed out Lean is for cost reduction, whereas Agility is for attaining flexibility. There are little empirical studies in literature that examined how Lean Agile paradigm impacts on supply chain performance. This paper aims to address this gap by studying the influence of Lean and Agility paradigms on a single commodity supply chain delivery performance in the aerospace industry. Data was collected from four separate 'Rigid pipes' supply chains to study how manufacturing alignment impacts on the delivery performance. Implications of the study to practitioners and academia are discussed and future research outlined.

Book review: Laurel Kamada, Hybrid Identities and Adolescent Girls: Being Half in Japan. Bristol: Multilingual Matters, 2010

Arguably, the catalyst for the best research studies using social analysis of discourse is personal ‘lived’ experience. This is certainly the case for Kamada, who, as a white American woman with a Japanese spouse, had to deal first hand with the racialization of her son. Like many other mixed-ethnic parents, she experienced the shock and disap-pointment of finding her child being racialized as ‘Chinese’ in America through peer group taunts, and constituted as gaijin (a foreigner) in his own homeland of Japan. As a member of an e-list of the (Japan) Bilingualism Special Interest Group (BSIG), Kamada learnt that other parents from the English-speaking foreign community in Japan had similar disturbing stories to tell of their mixed-ethnic children who, upon entering the Japanese school system, were mocked, bullied and marginalized by their peers. She men-tions a pervasive Japanese proverb which warns of diversity or difference getting squashed: ‘The nail that sticks up gets hammered down’. This imperative to conform to Japanese behavioural and discursive norms prompted Kamada’s quest to investigate the impact of ‘otherization’ on the identities of children of mixed parentage. In this fascinat-ing book, she shows that this pressure to conform is balanced by a corresponding cele-bration of ‘hybrid’ or mixed identities. The children in her study are also able to negotiate their identities positively as they come to terms with contradictory discursive notions of ‘Japaneseness’, ‘whiteness’ and ‘halfness/doubleness’.The discursive construction of identity has become a central concern amongst researchers across a wide range of academic disciplines within the humanities and the social sciences, and most existing work either concentrates on a specific identity cate-gory, such as gender, sexuality or national identity, or else offers a broader discussion of how identity is theorized. Kamada’s book is refreshing because it crosses the usual boundaries and offers divergent insights on identity in a number of ways. First, using the term ‘ethno-gendering’, she examines the ways in which six mixed-ethnic girls living in Japan accomplish and manage the relationship between their gender and ethnic ‘differ-ences’ from age 12 to 15. She analyses in close detail how their actions or displays within certain situated interactions might come into conflict with how they are seen or constituted by others. Second, Kamada’s study builds on contemporary writing on the benefits of hybridity where identities are fluid, flexible and indeterminate, and which contest the usual monolithic distinctions of gender, ethnicity, class, etc. Here, Kamada carves out an original space for her findings. While scholars have often investigated changing identities and language practices of young people who have been geographi-cally displaced and are newcomers to the local language, Kamada’s participants were all born and brought up in Japan, were fluent in Japanese and were relatively proficient in English. Third, the author refuses to conceptualize or theorize identity from a single given viewpoint in preference to others, but in postmodernist spirit draws upon multiple perspectives and frameworks of discourse analysis in order to create different forms of knowledge and understandings of her subject. Drawing on this ‘multi-perspectival’ approach, Kamada examines grammatical, lexical, rhetorical and interactional features from six extensive conversations, to show how her participants position their diverse identities in relation to their friends, to the researcher and to the outside world. Kamada’s study is driven by three clear aims. The first is to find out ‘whether there are any tensions and dilemmas in the ways adolescent girls of Japanese and “white” mixed parentage in Japan identify themselves in terms of ethnicity’. In Chapter 4, she shows how the girls indeed felt that they stood out as different and consequently experienced isolation, marginalization and bullying at school – although they were able to make better sense of this as they grew older, repositioning the bullies as pitiable. The second aim is to ask how, if at all, her participants celebrate their ethnicity, and furthermore, what kind of symbolic, linguistic and social capital they were able to claim for themselves on the basis of their hybrid identities. In Chapter 5, Kamada shows how the girls over time were able to constitute themselves as insiders while constituting ‘the Japanese’ as outsiders, and their network of mixed-ethnic friends was a key means to achieve this. In Chapter 6, the author develops this potential celebration of the girls’ mixed ethnicity by investigating the privileges they perceived it afforded them – for example, having the advantage of pos-sessing English proficiency and intercultural ‘savvy’ in a globalized world. Kamada’s third aim is to ask how her participants positioned themselves and performed their hybrid identities on the basis of their constituted appearance: that is, how the girls saw them-selves based on how they looked to others. In Chapter 7, the author shows that, while there are competing discourses at work, the girls are able to take up empowering positions within a discourse of ‘foreigner attractiveness’ or ‘a white-Western female beauty’ discourse, which provides them with a certain cachet among their Japanese peers. Throughout the book, Kamada adopts a highly self-reflexive perspective of her own position as author. For example, she interrogates the fact that she may have changed the lived reality of her six participants during the course of her research study. As the six girls, who were ‘best friends’, lived in different parts of the Morita region of Japan, she had to be proactive in organizing six separate ‘get-togethers’ through the course of her three-year study. She acknowledges that she did not collect ‘naturally occurring data’ but rather co-constructed opportunities for the girls to meet and talk on a regular basis. At these meetings, she encouraged the girls to discuss matters of identity, prompted by open-ended interview questions, by stimulus materials such as photos, articles and pic-tures, and by individual tasks such as drawing self-portraits. By giving her participants a platform in this way, Kamada not only elicited some very rich spoken data but also ‘helped in some way to shape the attitudes and self-images of the girls positively, in ways that might not have developed had these get-togethers not occurred’ (p. 221). While the data she gathers are indeed rich, it may well be asked whether there is a mismatch between the girls’ frank and engaging accounts of personal experience, and the social constructionist academic register in which these are later re-articulated. When Kamada writes, ‘Rina related how within the more narrow range of discourses that she had to draw on in her past, she was disempowered and marginalized’ (p. 118), we know that Rina’s actual words were very different. Would she really recognize, understand and agree with the reported speech of the researcher? This small omission of self-reflexivity apart – an omission which is true of most lin-guistic ethnography conducted today – Kamada has written a unique, engaging and thought-provoking book which offers a model to future discourse analysts investigating hybrid identities. The idea that speakers can draw upon competing discourses or reper-toires to constitute their identities in contrasting, creative and positive ways provides linguistic researchers with a clear orientation by which to analyse the contradictions of identity construction as they occur across time in different discursive contexts