Multiplicative sensitivity analysis and its role in development of simulation models

A procedure of extended sensitivity analysis for simulation models is developed which is applicable to the situation in which input uncertainties are specified in a multiplicative (rather than an additive) way. This type of specification usually occurs when error estimates are large relative to the parameter values. The input parameter errors are assumed to have log-normal distributions and the basis for this assumption is explained along with the advantages it provides. The new procedure, multiplicative sensitivity analysis, is developed for the purposes of internal model validation and identification of priorities for specific experimental and theoretical studies needed for a particular system being modelled. The applicability of the procedure in the very early stages of a research program is its main advantage and further expands the rôle of simulation models.     

Attachment of oysters to natural substrata by biologically induced marine carbonate cement

Oysters live permanently immobilised by cementation of the left valve to a hard substrate. The contact zone between oysters and natural substrata has been analysed using SEM imaging, electron dispersive X-ray microanalysis, electron backscatter diffraction and Raman spectroscopy and reveals the influence of both biogenic and non-biogenic processes in oyster cementation. Original adhesion is brought about by secretion of an organic component that acts as a nucleating surface onto which crystals precipitate. These crystals have a random orientation and are composed of high Mg calcite. This suggests that the crystals nucleating on the glue substrate are outwith the biological control experienced by the shell biomineralisation process and are formed by inorganic precipitation from seawater. It is proposed that oysters do not control or secrete crystalline cement. Instead, they adhere by secretion of an organic film onto which crystals precipitate from seawater.     

A systematic review of snake translocations to identify potential tactics for reducing postrelease effects

Advancements in the field of reintroduction biology are needed, but understanding of how to effectively conduct translocations, particularly with snakes, is lacking. We conducted a systematic review of snake translocation studies to identify potential tactics for reducing postrelease effects. We included studies on intentional, human-mediated, wild–wild, or captive–wild translocations to any location, regardless of motive or number of snakes translocated. Only studies that presented results for at least 1 of 4 outcomes (movement behavior, site fidelity, survival, or population establishment) were included. We systematically searched 4 databases for published studies and used 5 methods to search the gray literature. Our search and screening criteria yielded 121 data sources, representing 130 translocation cases. We quantified the association between 15 translocation tactics and short-term translocation outcomes by calculating odds ratios and used forest plots to display results. Snake translocations involved 47 species (from mainly 2 families), and most were motivated by research, were monitored for at least 6 months, occurred in North America, and took place from the 1990s onward. The odds of a positive snake translocation outcome were highest with release of captive reared or juvenile snakes, release of social groups together, delayed release, provision of environmental enrichment or social housing before release, or minimization of distance translocated. The odds of a positive outcome were lowest when snakes were released early in their active season. Our results do not demonstrate causation, but outcomes of snake translocation were associated with 8 tactics (4 of which were strongly correlated). In addition to targeted comparative studies, we recommend practitioners consider the possible influence of these tactics when planning snake translocations.     

Evaluating the cost-effectiveness of a monitoring system for improved evacuation from passenger ships

This paper presents an evaluation of the cost-effectiveness of a novel passenger monitoring system based on RFID technology for implementation onboard passenger ships. Such a system will be able to detect and keep track of passengers onboard the ship in emergency situations in order to provide crucial decision support to the officer in charge of evacuation. This will lead to increased safety and security on passenger ships. However, this increased safety will come at a certain cost. A methodology in line with Formal Safety Assessment is employed in order to assess the cost-effectiveness of the system, involving a thorough risk analysis.     

Assessment of water quality in the Alqueva Reservoir (Portugal) using bioassays

Background, aim, and scope  

Alqueva Reservoir is the biggest artificial freshwater reservoir in Europe and is an important water supply for human and agricultural consumption in the Alentejo region (Portugal). Pollution can impair environmental and human health status, and to assure water quality and ecological balance, it is crucial to frequently monitor water supplies. In this study, we used an ecotoxicological test battery to identify the potential toxicity of water from this reservoir.     

Synergistic effects caused by atrazine and terbuthylazine on chlorpyrifos toxicity to early-life stages of the zebrafish Danio rerio

This study examined the effects of three widely used pesticides that have been previously detected in aquatic systems neighbouring agricultural fields on the early-life stages of the zebrafish Danio rerio. Tests involving single exposures and binary combinations of the s-triazine herbicides (atrazine and terbuthylazine) and the organophosphate insecticide chlorpyrifos were performed. Several endpoints, such as swimming behaviour, morphological abnormalities and mortality, were studied. In addition, the inhibition of acetylcholinesterase (AChE) activity was investigated in order to evaluate the mode of action and toxicity of chlorpyrifos in the presence of these herbicides. Results indicate that both binary mixtures elicited synergistic responses on the swimming behaviour of zebrafish larvae. Moreover, although the herbicides were not effective inhibitors of the AChE on their own, a synergistic inhibition of the enzyme activity was obtained by exposure to mixtures with chlorpyrifos. We observed a correlation between impairment of swimming behaviour of the larvae and inhibition of AChE activity. This study supports previous studies concerning the risk assessment of mixtures since the toxicity may be underestimated when looking only at the single toxicants and not their mixtures.     

Promoting integration and cooperation for sustainability views from the symposium held at UNESCO headquarters September 19, 2013

This public symposium explored ways to integrate knowledge about and strengthen cooperation on complex and interconnected global sustainability issues. (The symposium was organized by the United Nations University (UNU), The University of Tokyo Integrated Research System for Sustainability Science (IR3S), as well as UNESCO. Co-organizers were the Ministry of Education, Culture, Sports, Science and Technology-Japan (MEXT) and the Japan Society for the Promotion of Science (JSPS). Participants included representatives from key institutes and UNESCO’s programs in the areas of water, ocean and ecological sciences as well as social and natural sciences, UNESCO Member states, scholars and policymakers. The symposium program and list of speakers is attached. See also www.isp.unu.edu). The central question put to symposium deliberations was one that many policy- and decision-makers as well as academic scholars struggle with today: how can we overcome barriers to action that will put societies around the world on a path to a more stable and sustainable future? This article examines the presentations made during the symposium and draws upon them to explore opportunities for sustainability scientists to help meet this challenge. The paper is divided into three parts: Part I provides a brief introduction that places the symposium in context of current debates on sustainability science and discusses (a) the role of UNESCO and (b) the relevance of sustainability science to policy- and decision-making for sustainable development. Part II examines three steps that can be taken now to overcome barriers to sustainability and the role of sustainability science in each (a) building societal and environmental resilience; (b) increasing collaboration across geographical and disciplinary boundaries as well as between scientists and decision-makers; and (c) enhancing education for sustainable development (ESD). The paper concludes with a review of why these keys are essential and steps that can be taken in the future to facilitate their widespread application at multiple scales.     

Implications of differing input data sources and approaches upon forest carbon stock estimation

Site index is an important forest inventory attribute that relates productivity and growth expectation of forests over time. In forest inventory programs, site index is used in conjunction with other forest inventory attributes (i.e., height, age) for the estimation of stand volume. In turn, stand volumes are used to estimate biomass (and biomass components) and enable conversion to carbon. In this research, we explore the implications and consequences of different estimates of site index on carbon stock characterization for a 2,500-ha Douglas-fir-dominated landscape located on Eastern Vancouver Island, British Columbia, Canada. We compared site index estimates from an existing forest inventory to estimates generated from a combination of forest inventory and light detection and ranging (LIDAR)-derived attributes and then examined the resultant differences in biomass estimates generated from a carbon budget model (Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3)). Significant differences were found between the original and LIDAR-derived site indices for all species types and for the resulting 5-m site classes (p?<?0.001). The LIDAR-derived site class was greater than the original site class for 42% of stands; however, 77% of stands were within ±1 site class of the original class. Differences in biomass estimates between the model scenarios were significant for both total stand biomass and biomass per hectare (p?<?0.001); differences for Douglas-fir-dominated stands (representing 85% of all stands) were not significant (p?=?0.288). Overall, the relationship between the two biomass estimates was strong (R ²?=?0.92, p?<?0.001), suggesting that in certain circumstances, LIDAR may have a role to play in site index estimation and biomass mapping.     

Returning home: resettlement of formerly abducted children in Northern Uganda

This exploratory qualitative study considers the subjective resettlement experiences of children forced into armed conflict in Northern Uganda from the perspectives of 11 former child combatants and 11 adult community members. A thematic analysis was performed on the narrative data. The bioecological model was used to provide a conceptual framework for key themes. Major findings included the overarching impact of ongoing armed conflict on returnees' lives, the important role of the family in supporting children's resettlement, the harassment of former child soldiers by community members, and the community's inability to support systematically the returning children in tangible ways. This study recommends that humanitarian services at all levels strengthen the capacity of families to care for the material and psychoemotional needs of former child soldiers within their communities.