26 resultados para Filtres rehausseurs de contours


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Objective: Positron emission tomography (PET)/CT scans can improve target definition in radiotherapy for non-small cell lung cancer (NSCLC). As staging PET/CT scans are increasingly available, we evaluated different methods for co-registration of staging PET/CT data to radiotherapy simulation (RTP) scans.

Methods: 10 patients underwent staging PET/CT followed by RTP PET/CT. On both scans, gross tumour volumes (GTVs) were delineated using CT (GTVCT) and PET display settings. Four PET-based contours (manual delineation, two threshold methods and a source-to-background ratio method) were delineated. The CT component of the staging scan was co-registered using both rigid and deformable techniques to the CT component of RTP PET/CT. Subsequently rigid registration and deformation warps were used to transfer PET and CT contours from the staging scan to the RTP scan. Dice’s similarity coefficient (DSC) was used to assess the registration accuracy of staging-based GTVs following both registration methods with the GTVs delineated on the RTP PET/CT scan.

Results: When the GTVCT delineated on the staging scan after both rigid registration and deformation was compared with the GTVCT on the RTP scan, a significant improvement in overlap (registration) using deformation was observed (mean DSC 0.66 for rigid registration and 0.82 for deformable registration, p50.008). A similar comparison for PET contours revealed no significant improvement in overlap with the use of deformable registration.

Conclusions: No consistent improvements in similarity measures were observed when deformable registration was used for transferring PET-based contours from a staging PET/CT. This suggests that currently the use of rigid registration remains the most appropriate method for RTP in NSCLC.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Double-breasting has been identified as where companies run union voice and non-union voice mechanisms across different plants. While research has focused on the incidence of such arrangements, there is a dearth of evidence into the dynamics of it. This article seeks to complement existing research by examining the contours of double-breasting in a case study organisation. The findings suggest that more research is necessary into the dynamics of double-breasting in terms of how voice in sites affects each other and the extent to which running different regimes affects the managerial agenda.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This article proposes developing the public bioethics aspect of stewardship and applying it to the EU as ‘supra-stewardship’, a tool for opening a discursive space for citizen participation in EU preparedness planning. With this in mind the article highlights some of the contours for engagement on the boundaries of responsibility and the production of governance distortions and failures brought out by attention to framing, distribution, vulnerability and learning. This should help citizens to tackle the complementary expert and public rationalities that undermine their involvement, contribute supplementary knowledge towards governance, and help promote institutional learning by the EU and resilience.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The national resource privilege, which holds that states are allowed to control all the natural resources found in their territory, is a cornerstone of international politics. Supporters of the national resource privilege claim that without the privilege states would fail to be sovereign and self-determining entities which provide for the needs of their citizens. However, as this paper shows the case is not as simple as that. In fact, control over resources must be carefully unpacked. Doing so shows that states do not require full control over all resources found in their territory in order to be sovereign. Moreover, sovereignty and self-determination come with a set of responsibilities and duties attached. Based on these observations the paper will sketch the contours of an alternative resource governance scheme built around the idea of an International Court of the Environment.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Mixed flow turbines can offer improvements over typical radial turbines used in automotive turbochargers, with regards to transient performance and low velocity ratio efficiency. Turbine rotor mass dominates the rotating inertia of the turbocharger, and any reductions of mass in the outer radii of the wheel, including the rotor back-disk, can significantly reduce this inertia and improve the acceleration of the assembly. Off-design, low velocity ratio conditions are typified by highly tangential flow at the rotor inlet and a non-zero inlet blade angle is preferred for such operating conditions. This is achievable in a Mixed Flow Turbine without increasing bending stresses within the rotor blade, which is beneficial in high speed and high inlet temperature turbine design. A range of mixed flow turbine rotors was designed with varying cone angle and inlet blade angle and each was assessed at a number of operating points. These rotors were based on an existing radial flow turbine, and both the hub and shroud contours and exducer geometry were maintained. The inertia of each rotor was also considered. The results indicated that there was a trade-off between efficiency and inertia for the rotors and certain designs may be beneficial for the transient performance of downsized, turbocharged engines.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The republican idea of non-domination stresses the importance of certain social relationships for a person’s freedom, showing that freedom is a social-relational state. While the idea of freedom as non-domination receives a lot of attention in the literature, republican theorists say surprisingly little about equality. Therefore, the aim of this paper is to carve out the contours of a republican conception of equality.. In so doing, I will argue that republican accounts of equality share a significant normative overlap with the idea of social equality. However, closer analysis of Philip Pettit’s account of ‘expressive egalitarianism’ (which Pettit sees as inherently connected to non-domination) and recent theories of social equality shows that republican non-domination – in contrast to what Pettit seems to claim – is not sufficient for securing (republican) social equality. In order to secure social equality for all, republicans would have to go beyond non-domination.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This article explores the contours of continued housing instability among a group of young people who are participants in a qualitative longitudinal study of youth homelessness in Dublin, Ireland, and considers the limitations of the ‘acculturation’ thesis in explaining long-term homelessness amongst the young. Baseline interviews were conducted with 40 young people, aged 14–23 years, in 2004, and follow-up interviews were conducted with 30 research participants successfully ‘tracked’ in 2005–06. By the time of follow-up, 17 of those interviewed had exited homelessness and 13 remained homeless. The article focuses on the latter group with the aim of exploring the processes and experiences associated with their continued homelessness. The findings presented demonstrate the adverse impact of their ongoing movement through emergency services targeting the under-18s, including their greater immersion in drug and criminal lifestyles. A majority had experienced one or more period of incarceration by the time of follow-up, and many were users of adult homeless services. Whilst some dimensions of young people's accounts are suggestive of a process of acculturation to street and hostel life, we argue that their continued homelessness is better explained as a consequence of their ongoing and unresolved transience and, in particular, their continued dependence on emergency hostel accommodation. The implications of the findings for policy and service provision for homeless young people are discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The use of nonviolent action is on the rise. From the Occupy Movement to the Arab Spring and mass protests on the streets of Brazil, activists across the world are increasingly using unarmed tactics to challenge oppressive, corrupt and unjust systems. But what exactly do we mean by nonviolence? How is it deployed and to what effect? Do nonviolent campaigns with political motivations differ from those driven by primarily economic concerns? What are the limits and opportunities for activists engaging in nonviolent action today? Is the growing number of nonviolence protests indicative of a new type of twenty-first century struggle or is it simply a passing trend?
Understanding Nonviolence: Contours and Contexts is the first book to offer a comprehensive introduction to nonviolence in theory and practice. Combining insightful analysis of key theoretical debates with fresh perspectives on contemporary and historical case studies, it explores the varied approaches, aims, and trajectories of nonviolent campaigns from Gandhi to the present day. With cutting-edge contributions from leading scholars and practitioners in the field, this accessible and lively book will be essential reading for activists, students and teachers of contentious politics, international security, and peace and conflict studies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND AND PURPOSE: To assess the impact of a standardized delineation protocol and training interventions on PET/CT-based target volume delineation (TVD) in NSCLC in a multicenter setting.

MATERIAL AND METHODS: Over a one-year period, 11 pairs, comprised each of a radiation oncologist and nuclear medicine physician with limited experience in PET/CT-based TVD for NSCLC from nine different countries took part in a training program through an International Atomic Energy Agency (IAEA) study (NCT02247713). Teams delineated gross tumor volume of the primary tumor, during and after training interventions, according to a provided delineation protocol. In-house developed software recorded the performed delineations, to allow visual inspection of strategies and to assess delineation accuracy.

RESULTS: Following the first training, overall concordance indices for 3 repetitive cases increased from 0.57±0.07 to 0.66±0.07. The overall mean surface distance between observer and expert contours decreased from -0.40±0.03 cm to -0.01±0.33 cm. After further training overall concordance indices for another 3 repetitive cases further increased from 0.64±0.06 to 0.80±0.05 (p=0.01). Mean surface distances decreased from -0.34±0.16 cm to -0.05±0.20 cm (p=0.01).

CONCLUSION: Multiple training interventions improve PET/CT-based TVD delineation accuracy in NSCLC and reduces interobserver variation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper begins by outlining and critiquing what we term the dominant anglophone model of neo-liberal community safety and crime prevention. As an alternative to this influential but flawed model, a comparative analysis is provided of the different constitutional-legal settlements in each of the five jurisdictions across the UK and the Republic of Ireland (ROI), and their uneven institutionalization of community safety. In the light of this it is argued that the nature of the anglophone community safety enterprise is actually subject to significant variation. Summarizing the contours of this variation facilitates our articulation of some core dimensions of community safety. Then, making use of Colebatch’s (2002) deconstruction of policy activity into categories of authority and expertise, and Brunsson’s (2002) distinction between policy talk, decisions and action, we put forward a way of understanding policy activity that avoids the twin dangers of ‘false particularism’ and ‘false universalism’ (Edwards and Hughes, 2005); that indicates a path for further empirical enquiry to assess the ‘reality’ of policy convergence; and that enables the engagement of researchers with normative questions about where community safety should be heading.