Age- and Sex-Specific Thorax Finite Element Model Development and Simulation

Objective: The shape, size, bone density, and cortical thickness of the thoracic skeleton vary significantly with age and sex, which can affect the injury tolerance, especially in at-risk populations such as the elderly. Computational modeling has emerged as a powerful and versatile tool to assess injury risk. However, current computational models only represent certain ages and sexes in the population. The purpose of this study was to morph an existing finite element (FE) model of the thorax to depict thorax morphology for males and females of ages 30 and 70 years old (YO) and to investigate the effect on injury risk.

Methods: Age- and sex-specific FE models were developed using thin-plate spline interpolation. In order to execute the thin-plate spline interpolation, homologous landmarks on the reference, target, and FE model are required. An image segmentation and registration algorithm was used to collect homologous rib and sternum landmark data from males and females aged 0–100 years. The Generalized Procrustes Analysis was applied to the homologous landmark data to quantify age- and sex-specific isolated shape changes in the thorax. The Global Human Body Models Consortium (GHBMC) 50th percentile male occupant model was morphed to create age- and sex-specific thoracic shape change models (scaled to a 50th percentile male size). To evaluate the thoracic response, 2 loading cases (frontal hub impact and lateral impact) were simulated to assess the importance of geometric and material property changes with age and sex.

Results: Due to the geometric and material property changes with age and sex, there were observed differences in the response of the thorax in both the frontal and lateral impacts. Material property changes alone had little to no effect on the maximum thoracic force or the maximum percent compression. With age, the thorax becomes stiffer due to superior rotation of the ribs, which can result in increased bone strain that can increase the risk of fracture. For the 70-YO models, the simulations predicted a higher number of rib fractures in comparison to the 30-YO models. The male models experienced more superior rotation of the ribs in comparison to the female models, which resulted in a higher number of rib fractures for the males.

Conclusion: In this study, age- and sex-specific thoracic models were developed and the biomechanical response was studied using frontal and lateral impact simulations. The development of these age- and sex-specific FE models of the thorax will lead to an improved understanding of the complex relationship between thoracic geometry, age, sex, and injury risk.     

Participatory and multi-level governance: applications to Aboriginal renewable energy projects

As provinces across Canada seek to diversify their domestic electricity supply and cope with the accelerating effects of anthropogenic climate change, new models of sustainability-focused economic development are being pursued. One critically important emerging paradigm involves First Nation (a Canadian term for indigenous) collaboration and leadership in renewable energy projects. In this comparative case study analysis, we consider two different governance approaches pursued in distinct renewable energy project contexts: the clean energy projects of the Ojibway Pic River First Nation band in northwestern Ontario and the NaiKun Offshore Wind Project proposed in the ocean territory of the Haida Nation off the coast of British Columbia (BC). Focusing on themes of participation and multi-level governance, the case studies highlight the importance of authority and control in decision processes, the primacy of ensuring that scale and quality of design are carefully scoped, and the shaping role of inclusiveness in planning for wholly sustainable energy futures. Taken together, these cases illustrate that fluid governance arrangements which exploit the particular capacities of each actor may give rise to trust that ultimately forms the foundation of a co-produced model of renewable energy governance. We argue that while collaboration might aim to be inclusive of all interested actors, it is important to consider the extent to which a project design might sufficiently incorporate a community's long-term vision. We conclude that truly sustainable renewable energy development requires a project design that reflects community values, incorporates community control, and incentivises indigenous ownership.     

Decentralization and people's participation in conservation: a comparative study from the Western Terai of Nepal

Nepal formally embarked on decentralized participatory conservation programmes in 1990. To assess who participates in and benefits from such programmes, stratified random questionnaire surveys of 234 households and interviews with 29 user group chairs were conducted in the buffer zones of two protected areas of the Nepalese Terai: Bardia National Park and Suklaphanta Wildlife Reserve. The Poisson regression shows that gender, education, household affluence, and conservation attitudes were significant predictors of people's participation in decentralized conservation programmes, while family size, ethnicity and resource dependency were not. The benefits of participation outweighed the costs based on respondents' estimates. The performance of grassroots organizations and levels of participation were correlated. Nepal's decentralized participatory conservation has achieved efficiency, relative equity and effectiveness to some extent. Yet the central government should devolve more power to local communities to sustain the achievements as well as to provide more equitable benefits to residents to ensure the effectiveness and sustainability of conservation programmes.     

Cleanup levels for dioxin-contaminated soils

EPA's use of a 1 part per billion (ppb) level for dioxin contamination in residential soils is shown to be too high and not protective of public health. It was derived in a 1984 cancer risk assessment by another federal agency, but it is inconsistent with risk-based levels of 2 to 4 parts per trillion (ppt) obtained by using EPA's standard risk assessment methods. EPA has called the 1 ppb level a policy-based level, which correctly distinguishes it from a risk or health-based cleanup standard. The 1984 assessment is shown in this article to have considerable shortcomings. For over a decade, dioxins have been left in soils at levels posing health risks and sometimes at levels that EPA is legally required to address. Moreover, noncancer effects have been ignored, but recent work has shown them to support action at low ppt levels. To protect public health, be consistent with current scientific knowledge and other EPA policies, reduce confusion in the environmental management community, and be responsive to public demands for stringent dioxin cleanups, new EPA policy guidance for dioxin soil cleanups is needed, and key elements are presented in this article. In an ad hoc fashion, EPA Region 4 has recently used a 200 ppt dioxin cleanup level for residential soil, acknowledged to correspond to a one-in-ten-thousand cancer risk, at two Superfund sites, which environmental professionals should be aware of. This suggests a shift in EPA policy.     

“Horizontal” and “vertical” diffusion: The cumulative influence of Impact and Benefit Agreements (IBAs) on mining policy-production in New Caledonia

The scale, duration and intensity of conflicts over mineral resources vary greatly. However, they always involve, in varying proportions, the triad stakeholder model—corporation, state, community—each element of which is internally heterogeneous. Increasingly, new players are entering the scene: international non-governmental organizations (NGOs), environmental grassroots groups, indigenous transnational networks, international aid and development agencies. Nevertheless, conflicts and arrangements around access to and control over mineral resources can take the apparent form of dyadic relationships between companies and local communities, resulting in negotiated company-community agreements, often called “Impact and Benefit Agreements” (IBAs). In our analysis, local agreements on mineral resource governance are seen as building blocks in the production of mining policy “from below”, even though they seem at first sight to exclude the state. This paper argues that these agreements, and the negotiations surrounding them, inform debates around mining through both “horizontal diffusion” (influence on other localities facing similar situations) and “vertical diffusion” (influence on policy design and implementation at upper political and administrative levels). This diffusion may occur in a “positive” sense, effecting further change in line with the intent of the original agreement, or in a “negative” one, actually making substantive change less likely, whether at a community or policy level. We build this argument through two case studies from New Caledonia, in the south-west Pacific, where mining has long been a key issue, especially in the current context of “negotiated decolonization” launched by the 1998 Nouméa Accord.     

IMPLICATIONS OF A DRAWDOWN OF THE SNAKE-COLUMBIA RWER ON BARGE TRANSPORTATION1

ABSTRACT: The listing of the Snake-Columbia River salmon under the Endangered species Cut will lead to a set of river management changes aimed at species recovery. One measure almost certain to be implemented is a periodic river drawdown. A drawdown will speed fish migration downriver but will also temporarily close the river to barge transportation. Grain shippers in the region rely on the barge carriage to move a significant share of annual production to export elevators on the Lower Columbia. A number of other bulk commodities utilize barges as well. This study outlines the aggregate and distributional economic implications of a suspension of barge transportation resulting from a river drawdown.