Mitigation of Fatigue Damage in Self-Healing Vascular Materials

The fatigue response of an epoxy matrix containing vasculature for the delivery of liquid healing agents is investigated. The release of a rapidly curing, two-part epoxy healing chemistry into the wake of a propagating crack reduces the rate of crack extension by shielding the crack tip from the full range of applied stress intensity factor. Crack propagation is studied for a variety of loading conditions, with the maximum applied stress intensity factor ranging from 62 to 84% of the quasi-static fracture toughness of the material. At the highest level of applied load, the rate of mechanical damage is so fast that the healing agents do not fully mix and polymerize, and the effect of healing is minimal. The self-healing response is most effective at impeding the slower propagating cracks, with complete crack arrest occurring at the lowest level of applied load, and reductions of 79–84% in the rate of crack extension at intermediate loads.

'Sometimes I wish I was an "ex" ex-prisoner': identity processes in the collective action participation of former prisoners in Northern Ireland

Since the signing of the Northern Ireland peace agreement a plethora of community based prisoner self-help organisations have been established wherein former prisoners staff, manage and deliver services to colleagues. By forging and maintaining their collective identities through community based mutual aid, members of these self-help organisations have progressed to create not only individual change/assistance but have also developed and evolved to tackle serious wider social issues which impact on the members of their organisations. This article critically analyses how the conditions of a post conflict society can influence both the development and evolution of these organisations and also how members situate their claims about the self in the organisation and beyond. Using the social movement framework it is argued that the work of these self-help organisations have given rise to a new politics of identity … that is the ‘politically motivated’ ex-prisoner. ©2013 Taylor & Francis

Does Affirmative Action Work? Evidence from the Operation of Fair Employment Legislation in Northern Ireland

An affirmative action programme, established by the Fair Employment (Northern Ireland) Act 1989, has been an important attempt to ensure ‘fair participation’ in employment for both Catholics and Protestants in Northern Ireland since 1990. The programme includes detailed monitoring of the community background of employees and requires employers to undertake remedial action where fair participation is not evident. Agreements were concluded between the regulatory agency and many employers specifying what affirmative action measures were required. Based on the annual monitoring returns submitted between 1990 and 2005, this article evaluates the effectiveness of the affirmative action programme in promoting fair employment participation using fixed effects models. The analysis shows that there has been a general shift towards workforce integration in Northern Ireland but the increase of under-represented groups in agreement concerns is greater than in concerns with no agreement. The success of agreements, however, is limited to certain industrial sectors and medium-sized enterprises.

The expression of pain in infants and toddlers:developmental changes in facial action

Age-related changes in the facial expression of pain during the first 18 months of life have important implications for our understanding of pain and pain assessment. We examined facial reactions video recorded during routine immunization injections in 75 infants stratified into 2-, 4-, 6-, 12-, and 18-month age groups. Two facial coding systems differing in the amount of detail extracted were applied to the records. In addition, parents completed a brief questionnaire that assessed child temperament and provided background information. Parents' efforts to soothe the children also were described. While there were consistencies in facial displays over the age groups, there also were differences on both measures of facial activity, indicating systematic variation in the nature and severity of distress. The least pain was expressed by the 4-month age group. Temperament was not related to the degree of pain expressed. Systematic variations in parental soothing behaviour indicated accommodation to the age of the child. Reasons for the differing patterns of facial activity are examined, with attention paid to the development of inhibitory mechanisms and the role of negative emotions such as anger and anxiety.

Pain expression in neonates:facial action and cry

Pain expression in neonates instigated by heel-lance for blood sampling purposes was systematically described using measures of facial expression and cry and compared across sleep/waking states and sex. From gate-control theory it was hypothesized that pain behavior would vary with the ongoing functional state of the infant, rather than solely reflecting tissue insult. Awake-alert but inactive infants responded with the most facial activity, consistent with current views that infants in this state are most receptive to environmental stimulation. Infants in quiet sleep showed the least facial reaction and the longest latency to cry. Fundamental frequency of cry was not related to sleep/waking state. This suggested that findings from the cry literature on qualities of pain cry as a reflection of nervous system 'stress', in unwell newborns, do not generalize directly to healthy infants as a function of state. Sex differences were apparent in speed of response, with boys showing shorter time to cry and to display facial action following heel-lance. The findings of facial action variation across sleep/waking state were interpreted as indicating that the biological and behavioral context of pain events affects behavioral expression, even at the earliest time developmentally, before the opportunity for learned response patterns occurs. Issues raised by the study include the importance of using measurement techniques which are independent of preconceived categories of affective response.

Arching or Compressive Membrane Action in Reinforced Concrete Slabs

Arching or compressive membrane action (CMA) in reinforced concrete slabs occurs as a result of the great difference between the tensile and compressive strength of concrete. Cracking of the concrete causes a migration of the neutral axis which is accompanied by in-plane expansion of the slab at its boundaries. If this natural tendency to expand is restrained, the development of arching action enhances the strength of the slab. The term arching action is normally used to describe the arching phenomenon in one-way spanning slabs and compressive membrane action is normally used to describe the arching phenomenon in two-
way spanning slabs. This encyclopedic article presents the background to the discovery of the phenomenon of arching action and presents a factual history of the approaches to the treatment of arching action in the United Kingdom and North American bridge deck design codes. The article summarises the theoretical methodology used in the United Kingdom Design Manual for Roads and Bridges, BD81/02, which was based on the work by Kirkpatrick, Rankin & Long at Queen's University Belfast.

Community identity as resource and context: A mixed method investigation of coping and collective action in a disadvantaged community

Community identities enhance well-being through the provision of social support and feelings of collective efficacy as well as by acting as a basis for collective action and social change. However, the precise mechanisms through which community identity acts to enhance well-being are complicated by stigmatisation which potentially undermines solidarity and collective action. The present research examines a real-world stigmatised community group in order to investigate: (1) the community identity factors that act to enhance well-being, and (2) the consequences of community identity for community action. Study 1 consisted of a household survey conducted in disadvantaged areas of Limerick city in Ireland. Participants (n=322) completed measures of community identification, social support, collective efficacy, community action, and psychological well-being. Mediation analysis indicated that perceptions of collective efficacy mediated the relationship between identification and well-being. However, levels of self-reported community action were low and unrelated to community identification. In Study 2, twelve follow–up multiple-participant interviews with residents and community group workers were thematically analysed, revealing high levels of stigmatisation and opposition to identity-related collective action. These findings suggest the potential for stigma to reduce collective action through undermining solidarity and social support.

Common-sense knowledge for a computer vision system for human action recognition

This work presents a novel approach for human action recognition based on the combination of computer vision techniques and common-sense knowledge and reasoning capabilities. The emphasis of this work is on how common sense has to be leveraged to a vision-based human action recognition so that nonsensical errors can be amended at the understanding stage. The proposed framework is to be deployed in a realistic environment in which humans behave rationally, that is, motivated by an aim or a reason. © 2012 Springer-Verlag.

Common-sense reasoning for human action recognition

This paper presents a novel method that leverages reasoning capabilities in a computer vision system dedicated to human action recognition. The proposed methodology is decomposed into two stages. First, a machine learning based algorithm - known as bag of words - gives a first estimate of action classification from video sequences, by performing an image feature analysis. Those results are afterward passed to a common-sense reasoning system, which analyses, selects and corrects the initial estimation yielded by the machine learning algorithm. This second stage resorts to the knowledge implicit in the rationality that motivates human behaviour. Experiments are performed in realistic conditions, where poor recognition rates by the machine learning techniques are significantly improved by the second stage in which common-sense knowledge and reasoning capabilities have been leveraged. This demonstrates the value of integrating common-sense capabilities into a computer vision pipeline. © 2012 Elsevier B.V. All rights reserved.