974 resultados para head-group
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Purpose – This paper aims to present a novel rapid prototyping (RP) fabrication methods and preliminary characterization for chitosan scaffolds. Design – A desktop rapid prototyping robot dispensing (RPBOD) system has been developed to fabricate scaffolds for tissue engineering (TE) applications. The system is a computer-controlled four-axis machine with a multiple-dispenser head. Neutralization of the acetic acid by the sodium hydroxide results in a precipitate to form a gel-like chitosan strand. The scaffold properties were characterized by scanning electron microscopy, porosity calculation and compression test. An example of fabrication of a freeform hydrogel scaffold is demonstrated. The required geometric data for the freeform scaffold were obtained from CT-scan images and the dispensing path control data were converted form its volume model. The applications of the scaffolds are discussed based on its potential for TE. Findings – It is shown that the RPBOD system can be interfaced with imaging techniques and computational modeling to produce scaffolds which can be customized in overall size and shape allowing tissue-engineered grafts to be tailored to specific applications or even for individual patients. Research limitations/implications – Important challenges for further research are the incorporation of growth factors, as well as cell seeding into the 3D dispensing plotting materials. Improvements regarding the mechanical properties of the scaffolds are also necessary. Originality/value – One of the important aspects of TE is the design scaffolds. For customized TE, it is essential to be able to fabricate 3D scaffolds of various geometric shapes, in order to repair tissue defects. RP or solid free-form fabrication techniques hold great promise for designing 3D customized scaffolds; yet traditional cell-seeding techniques may not provide enough cell mass for larger constructs. This paper presents a novel attempt to fabricate 3D scaffolds, using hydrogels which in the future can be combined with cells.
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Internationally, collection of reliable data on new and evolving health-care roles is crucial. We describe a protocol for design and administration of a national census of an emergent health-care role, namely nurse practitioners in Australia using databases held by regulatory authorities. A questionnaire was developed to obtain data on the role and scope of practice of Australian nurse practitioners. Our tool comprised five sections and included a total of 56 questions, using 28 existing items from the National Nursing and Midwifery Labour Force Census and nine items recommended in the Nurse Practitioner Workforce Planning Minimum Data Set. Australian Nurse Registering Authorities (n = 6) distributed the survey on our behalf. This paper outlines our instrument and methods. The survey was administered to 238 authorized Australian nurse practitioners (85% response rate). Rigorous collection of standardized items will ensure health policy is informed by reliable and valid data. We will re-administer the survey 2 years following the first survey to measure change over time.
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The relationship between the quality of parent-child interactions and positive child developmental trajectories is well established (Guralnick, 2006; Shonkoff & Meissels, 2000; Zubrick et al., 2008). However, a range of parental, family, and socio-economic factors can pose risks to parents’ capacity to participate in quality interactions with their children. In particular, families with a child with a disability have been found to have higher levels of parenting stress, and are more likely to experience economic disadvantage, as well as social isolation. The importance of early interventions to promote positive parenting and child development for these families is widely recognised (Shonkoff & Meissels, 2000). However, to date, there is a lack of evidence about the effectiveness of early parenting programs for families who have a young child with a disability. This thesis investigates the impact of a music therapy parenting program, Sing & Grow, on 201 parent-child dyads who attended programs specifically targeted to parents who had a young child with a disability. Sing & Grow is an Australian national early parenting intervention funded by the Australian Government Department of Families, Housing, Community Services and Indigenous Affairs and delivered by Playgroup Queensland. It is designed and delivered by Registered Music Therapists for families with children aged from birth to three years. It aims to improve parenting skills and confidence, improve family functioning (positive parent-child interactions), enhance child development, and provide social networking opportunities to socially isolated families. The intervention targets a range of families in circumstances that have the potential to impact negatively on family functioning. This thesis uses data from the National Evaluation Study of Sing & Grow from programs which were targeted at families who had a young child with a disability. Three studies were conducted to address the objectives of this thesis. Study 1 examines the effects of the Sing & Grow intervention on parent reported pre and post parent mental health, parenting confidence, parenting skills, and child development, and other parent reported outcomes including social support, use of intervention resources, satisfaction with the intervention and perceived benefits of and barriers to participation. Significant improvements from pre to post were found for parent mental health and parent reported child communication and social skills, along with evidence that parents were very satisfied with the program and that it brought social benefits to families. Study 2 explored the pre to post effects of the intervention on children’s developmental skills and parent-child interactions using observational ratings made by clinicians. Significant pre to post improvements were found for parenting sensitivity, parental engagement with child and acceptance of child as well as for child responsiveness to parent, interest, and participation in the intervention, and social skills. Study 3 examined the nature of child and family characteristics that predicted better outcomes for families while taking account of the level of participation in the program. An overall outcome index was calculated and served as the dependent variable in a logistic regression analysis. Families who attended six or more sessions and mothers who had not completed high school were more likely to have higher outcome scores at post intervention than those who attended fewer sessions and those with more educated mothers respectively. The findings of this research indicate that the intervention had a positive impact on participants’ mental health, parenting behaviours and child development and that level of attendance was associated with better outcomes. There was also evidence that the program reached its target of high risk families (i.e., families in which mothers had lower educational levels) and that for these families better outcomes were achieved. There were also indications that the program was accessible and highly regarded by families and that it promoted social connections for participants. A theoretical model of how the intervention is currently working for families is proposed to explain the connections between early parenting, child development and maternal wellbeing. However, more research is required to further elucidate the mechanisms by which the intervention creates change for families. This research presents promising evidence that a short term group music therapy program can elicit important therapeutic benefits for families who have a child with a disability.
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A group key exchange (GKE) protocol allows a set of parties to agree upon a common secret session key over a public network. In this thesis, we focus on designing efficient GKE protocols using public key techniques and appropriately revising security models for GKE protocols. For the purpose of modelling and analysing the security of GKE protocols we apply the widely accepted computational complexity approach. The contributions of the thesis to the area of GKE protocols are manifold. We propose the first GKE protocol that requires only one round of communication and is proven secure in the standard model. Our protocol is generically constructed from a key encapsulation mechanism (KEM). We also suggest an efficient KEM from the literature, which satisfies the underlying security notion, to instantiate the generic protocol. We then concentrate on enhancing the security of one-round GKE protocols. A new model of security for forward secure GKE protocols is introduced and a generic one-round GKE protocol with forward security is then presented. The security of this protocol is also proven in the standard model. We also propose an efficient forward secure encryption scheme that can be used to instantiate the generic GKE protocol. Our next contributions are to the security models of GKE protocols. We observe that the analysis of GKE protocols has not been as extensive as that of two-party key exchange protocols. Particularly, the security attribute of key compromise impersonation (KCI) resilience has so far been ignored for GKE protocols. We model the security of GKE protocols addressing KCI attacks by both outsider and insider adversaries. We then show that a few existing protocols are not secure against KCI attacks. A new proof of security for an existing GKE protocol is given under the revised model assuming random oracles. Subsequently, we treat the security of GKE protocols in the universal composability (UC) framework. We present a new UC ideal functionality for GKE protocols capturing the security attribute of contributiveness. An existing protocol with minor revisions is then shown to realize our functionality in the random oracle model. Finally, we explore the possibility of constructing GKE protocols in the attribute-based setting. We introduce the concept of attribute-based group key exchange (AB-GKE). A security model for AB-GKE and a one-round AB-GKE protocol satisfying our security notion are presented. The protocol is generically constructed from a new cryptographic primitive called encapsulation policy attribute-based KEM (EP-AB-KEM), which we introduce in this thesis. We also present a new EP-AB-KEM with a proof of security assuming generic groups and random oracles. The EP-AB-KEM can be used to instantiate our generic AB-GKE protocol.
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Knowledge of the accuracy of dose calculations in intensity-modulated radiotherapy of the head and neck is essential for clinical confidence in these highly conformal treatments. High dose gradients are frequently placed very close to critical structures, such as the spinal cord, and good coverage of complex shaped nodal target volumes is important for long term-local control. A phantom study is presented comparing the performance of standard clinical pencil-beam and collapsed-cone dose algorithms to Monte Carlo calculation and three-dimensional gel dosimetry measurement. All calculations and measurements are normalized to the median dose in the primary planning target volume, making this a purely relative study. The phantom simulates tissue, air and bone for a typical neck section and is treated using an inverse-planned 5-field IMRT treatment, similar in character to clinically used class solutions. Results indicate that the pencil-beam algorithm fails to correctly model the relative dose distribution surrounding the air cavity, leading to an overestimate of the target coverage. The collapsed-cone and Monte Carlo results are very similar, indicating that the clinical collapsed-cone algorithm is perfectly sufficient for routine clinical use. The gel measurement shows generally good agreement with the collapsed-cone and Monte Carlo calculated dose, particularly in the spinal cord dose and nodal target coverage, thus giving greater confidence in the use of this class solution.
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In normal child development, both individual and group pretense first emerges at approximately two years of age. The metarepresentational account of pretense holds that children already have the concept PRETEND when they first engage in early group pretense. A behavioristic account suggests that early group pretense is analogous to early beliefs or desires and thus require no mental state concepts. I argue that a behavioral account does not explain the actual behavior observed in children and it cannot explain how children come to understand that a specific action is one of pretense versus one of belief. I conclude that a mentalistic explanation of pretense best explains the behavior under consideration.
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This chapter aims to situate values education as a core component of social science pre-service teacher education. In particular, it reflects on an experiment in embedding a values laden Global Education perspective in a fourth year social science curriculum method unit. This unit was designed and taught by the researcher on the assumption that beginning social science teachers need to be empowered with pedagogical skills and new dispositions to deal with value laden emerging global and regional concerns in their secondary school classrooms. Moreover, it was assumed that when pre-service teachers engage in dynamic and interactive learning experiences in their curriculum unit, they commence the process of ‘capacity building’ those skills which prepare them for their own lifelong professional learning. This approach to values education also aimed at providing pre-service teachers with opportunities to ‘create deep understandings of teaching and learning’ (Barnes, 1989, p. 17) by reflecting on the ways in which ‘pedagogy can be transformative’ (Lovat and Toomey, 2011 add page no from Chapter One). It was assumed that this tertiary experience would foster the sine qua non of teaching – a commitment to students and their learning. Central to fostering new ‘dispositions’ through this approach, was the belief in the power of pedagogy to make the difference in enhancing student participation and learning. In this sense, this experiment in values education in secondary social science pre-service teacher education aligns with the Troika metaphor for a paradigm change, articulated by Lovat and Toomey (2009) in Chapter One.
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Within a surveillance video, occlusions are commonplace, and accurately resolving these occlusions is key when seeking to accurately track objects. The challenge of accurately segmenting objects is further complicated by the fact that within many real-world surveillance environments, the objects appear very similar. For example, footage of pedestrians in a city environment will consist of many people wearing dark suits. In this paper, we propose a novel technique to segment groups and resolve occlusions using optical flow discontinuities. We demonstrate that the ratio of continuous to discontinuous pixels within a region can be used to locate the overlapping edges, and incorporate this into an object tracking framework. Results on a portion of the ETISEO database show that the proposed algorithm results in improved tracking performance overall, and improved tracking within occlusions.
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The relationship between participation in civic and political activities and membership of voluntary associations is now well established. What is less clear is the relative impacts of how much time people spend on group activities (associational intensity), and the number and type of groups that individuals are involved with (associational scope). Does it matter in terms of civic engagement, for example, whether one is a member of a quilting-circle or trade union? Does it matter whether association ‘membership’ is simply an annual payment or a major commitment of time and energy? In this article, we use a large survey to explore these questions empirically by focusing on the membership patterns and civic engagement practices of 4,001 citizens drawn from eight suburbs across Greater Melbourne, Australia. Our findings indicate that, while associational intensity is positively related to civic engagement, associational scope (the number of group memberships per person), is a more influential determinant of the level of civic and political participation. The results also suggest that while all forms of associationalism are important in terms of fostering greater levels of civic activity, not all forms have the same impact.
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Drivers are known to be optimistic about their risk of crash involvement, believing that they are less likely to be involved in a crash than other drivers. However, little comparative research has been conducted among other road users. In addition, optimism about crash risk is conceptualised as applying only to an individual’s assessment of his or her personal risk of crash involvement. The possibility that the self-serving nature of optimism about safety might be generalised to the group-level as a cyclist or a pedestrian, i.e., becoming group-serving rather than self-serving, has been overlooked in relation to road safety. This study analysed a subset of data collected as part of a larger research project on the visibility of pedestrians, cyclists and road workers, focusing on a set of questionnaire items administered to 406 pedestrians, 838 cyclists and 622 drivers. The items related to safety in various scenarios involving drivers, pedestrians and cyclists, allowing predictions to be derived about group differences in agreement with items based on the assumption that the results would exhibit group-serving bias. Analysis of the responses indicated that specific hypotheses about group-serving interpretations of safety and responsibility were supported in 22 of the 26 comparisons. When the nine comparisons relevant to low lighting conditions were considered separately, seven were found to be supported. The findings of the research have implications for public education and for the likely acceptance of messages which are inconsistent with current assumptions and expectations of pedestrians and cyclists. They also suggest that research into group-serving interpretations of safety, even for temporary roles rather than enduring groups, could be fruitful. Further, there is an implication that gains in safety can be made by better educating road users about the limitations of their visibility and the ramifications of this for their own road safety, particularly in low light.
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Changes in stride characteristics and gait rhythmicity characterize gait in Parkinson's disease and are widely believed to contribute to falls in this population. However, few studies have examined gait in PD patients who fall. This study reports on the complexities of walking in PD patients who reported falling during a 12-month follow-up. Forty-nine patients clinically diagnosed with idiopathic PD and 34 controls had their gait assessed using three-dimensional motion analysis. Of the PD patients, 32 (65%) reported at least one fall during the follow-up compared with 17 (50%) controls. The results showed that PD patients had increased stride timing variability, reduced arm swing and walked with a more stooped posture than controls. Additionally, PD fallers took shorter strides, walked slower, spent more time in double-support, had poorer gait stability ratios and did not project their center of mass as far forward of their base of support when compared with controls. These stride changes were accompanied by a reduced range of angular motion for the hip and knee joints. Relative to walking velocity, PD fallers had increased mediolateral head motion compared with PD nonfallers and controls. Therefore, head motion could exceed “normal” limits, if patients increased their walking speed to match healthy individuals. This could be a limiting factor for improving gait in PD and emphasizes the importance of clinically assessing gait to facilitate the early identification of PD patients with a higher risk of falling.
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Teaching The Global Dimension (2007) is intended for primary and secondary teachers, pre-service teachers and educators interested in fostering global concerns in the education system. It aims at linking theory and practice and is structured as follows. Part 1, the global dimension, proposes an educational framework for understanding global concerns. Individual chapters in this section deal with some educational responses to global issues and the ways in which young people might become, in Hick’s terms, more “world-minded”. In the first two chapters, Hicks presents first, some educational responses to global issues that have emerged in recent decades, and second, an outline of the evolution of global education as a specific field. As with all the chapters in this book, most of the examples are drawn from the United Kingdom. Young people’s concerns, student teachers’ views and the teaching of controversial issues, comprise the other chapters in this section. Taken collectively, the chapters in Part 2 articulate the conceptual framework for developing, teaching and evaluating a global dimension across the curriculum. Individual chapters in this section, written by a range of authors, explore eight key concepts considered necessary to underpin appropriate learning experiences in the classroom. These are conflict, social justice, values and perceptions, sustainability, interdependence, human rights, diversity and citizenship. These chapters are engaging and well structured. Their common format consists of a succinct introduction, reference to positive action for change, and examples of recent effective classroom practice. Two chapters comprise the final section of this book and suggest different ways in which the global dimension can be achieved in the primary and the secondary classroom.
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Engineering graduates of today are required to adapt to a rapidly changing work environment. In particular, they are expected to demonstrate enhanced capabilities in both mono-disciplinary and multi-disciplinary teamwork environments. Engineering education needs, as a result, to further focus on developing group work capabilities amongst engineering graduates. Over the last two years, the authors trialed various group work strategies across two engineering disciplines. In particular, the effect of group formation on students' performance, task management, and social loafing was analyzed. A recently developed online teamwork management tool, Teamworker, was used to collect students' experience of the group work. Analysis showed that students who were allowed to freely allocate to any group were less likely to report loafing from other team members, than students who were pre-allocated to a group. It also showed that performance was more affected by the presence or absence of a leader in pre-allocated rather than free-allocated groups.
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Project focused group work is significant in developing social and personal skills as well as extending the ability to identify, formulate and solve engineering problems. As a result of increasing undergraduate class sizes, along with the requirement for many students to work part-time, group projects, peer and collaborative learning are seen as a fundamental part of engineering education. Group formation, connection to learning objectives and fairness of assessment has been widely reported as major issues that leave students dissatisfied with group project based units. Several strategies were trialled including a study of formation of groups by different methods across two engineering disciplines over the past 2 years. Other strategies involved a more structured approach to assessment practices of civil and electrical engineering disciplines design units. A confidential online teamwork management tool was used to collect and collate student self and peer assessment ratings and used for both formative feedback as well as assessment purposes. Student satisfaction and overall academic results in these subjects have improved since the introduction of these interventions. Both student and staff feedback highlight this approach as enhancing student engagement and satisfaction, improved student understanding of group roles, reducing number of dysfunctional groups whilst requiring less commitment of academic resources.