The Impact of Recreation on Barrier Islands: A Case Study on Masonboro Island

Since 1992, coastal researchers at the University of North Carolina at Wilmington have been documenting the impacts of human recreational use on Masonboro Island, a component of the North Carolina National Estuarine Research Reserve, and the subsequent natural processes that mitigate these impacts. Both short-term and long-term natural mitigational processes were identified. The effects of these processes were found to be much more rapid than similar impacts on typical terrestrial settings. However, careful examination of the data suggests that both physical location of the impact site and natural variability of weather patterns and events play a role. Management implications of these findings are proposed.     

REVERSAL OF THE DOUBLE－STRANDED－RNA－INDUCED INHIBITION OF PROTEIN SYNTHESIS BY A CATALYTICALLY INACTIVE MUTANT OF THE PROTEIN

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Wetlands protection: The regulatory role of the U.S. army corps of engineers

The U.S. Army Corps of Engineers administers the only nationwide regulatory program that controls development activities in U.S. waters and wetlands. This article examines the statutory authorities, jurisdictional limitations, and evolution of the current Corps regulations, which express a strong policy to protect wetlands, estuaries, and tidal waters from unnecessary dredging, filling, or other alteration. The article explains the organization and procedures of the U.S. Army Corps of Engineers and examines in detail several precedential permit cases which have developed and implemented the Corps “wetlands policy.”; The article also evaluates current and potential policies underlying the regulatory efforts of the Corps of Engineers.     

Assessment and Promotion of the Great Barrier Reef's Human Dimensions Through Collaboration

Increasingly, natural resource managers see the marine protected areas that they are responsible for as linked social-ecological systems. This requires an equal focus on managing for both natural and human dimensions of the protected estate. Consequently, identification of indicators that represent the human dimensions of Large Scale Marine Protected Areas (LSMPAs) such as the Great Barrier Reef (GBR) is critical if these values are to be properly considered as part of standard management practice. Assessment and monitoring of the human dimensions of LSMPAs requires a replicable, collaborative process, rolled out at local scales but comparable across vast, socially and geographically diverse areas. This paper explores the application of a process for the development, assessment, and monitoring of the GBR's human dimensions. The process includes (a) development of a conceptual framework that links indicator sets to the desired state of the GBR's human dimensions; and (b) a collaborative approach including ten practical steps to implement assessment, monitoring, and benchmarking of the human dimensions of an LSMPA. We conclude with examination of challenges and opportunities for implementing this process in the GBR context, specifically with respect to the targets and objectives of the Reef 2050 Long-Term Sustainability Plan.     

Modelling minimum-time manoeuvering with global optimisation of local receding horizon control

In this paper, we explore the notion that a human driver uses a receding horizon model predictive control (MPC) scheme for minimum-time manoeuvering. However, MPC is an inherently sub-optimal control scheme because not all future information is incorporated into its finite preview horizon. In many practical applications, this sub-optimality is tolerated as the solution is sufficiently close to optimal. However, it is known that professional drivers have the ability to learn driving circuits and exploit its features to minimise their global manoeuvering time. In this paper, we will model their process with a cascaded optimisation structure. Therein, the inner-loop features a local MPC scheme tasked with finding the control inputs that achieve a blended objective of minimising time and maximising velocity in each preview horizon/distance. The outer loop of this cascaded structure computes the best set of weights for the two components of the local objectives in order to minimise the global manoeuvering time. The proposed cascaded optimisation and control approach is compared against a straight-forward fixed-cost time optimal MPC applied to minimum-time manoeuvering over two well-known race courses. The paper also includes an extended literature review and details of the computational formulation of the model approach.     

Suspended sediment and erosion dynamics in Kugmallit Bay and Beaufort Sea during ice-free conditions

The Mackenzie River is the largest river on the North American side of the Arctic and its huge freshwater and sediment load impacts the Canadian Beaufort Shelf. Huge quantities of sediment and associated organic carbon are transported in the Mackenzie plume into the interior of the Arctic Ocean mainly during the freshet (May to September). Changing climate scenarios portend increased coastal erosion and resuspension that lead to altered river-shelf-slope particle budgets. We measured sedimentation rates, suspended particulate matter (SPM), particle size and settling rates during ice-free conditions in Kugmallit Bay (3–5 m depth). Additionally, measurements of erosion rate, critical shear stress, particle size distribution and resuspension threshold of bottom sediments were examined at four regionally contrasting sites (33–523 m depth) on the Canadian Beaufort Shelf using a new method for assessing sediment erosion. Wind induced resuspension was evidenced by a strong relationship between SPM and wind speed in Kugmallit Bay. Deployment of sediment traps showed decreasing sedimentation rates at sites along an inshore–offshore transect ranging from 5400 to 3700 g m^− 2 day^− 1. Particle settling rates and size distributions measured using a Perspex settling chamber showed strong relationships between equivalent spherical diameter (ESD) and particle settling rates (r² = 0.91). Mean settling rates were 0.72 cm s^− 1 with corresponding ESD values of 0.9 mm. Undisturbed sediment cores were exposed to shear stress in an attempt to compare differences in sediment stability across the shelf during September to October 2003. Shear was generated by vertically oscillating a perforated disc at controlled frequencies corresponding to calibrated shear velocity using a piston grid erosion device. Critical (Type I) erosion thresholds (u) varied between 1.1 and 1.3 cm s^− 1 with no obvious differences in location. Sediments at the deepest site Amundsen Gulf displayed the highest erosion rates (22–54 g m^− 2 min^− 1) with resuspended particle sizes ranging from 100 to 930 µm for all sites. There was no indication of biotic influence on sediment stability, although our cores did not display a fluff layer of unconsolidated sediment. Concurrent studies in the delta and shelf region suggest the importance of a nepheloid layer which transports suspended particles to the slope. Continuous cycles of resuspension, deposition, and horizontal advection may intensify with reduction of sea ice in this region. Our measurements coupled with studies of circulation and cross-shelf exchange allow parameterization and modeling of particle dynamics and carbon fluxes under various climate change scenarios.     

An Assessment of Coastal Development and Land Use Change Using the DPSIR Framework: Case Studies from the Eastern Cape,South Africa

Coastal areas are experiencing high levels of development, largely driven by a number of aesthetic and recreational factors, increased mobility, availability of disposable income for middle and upper income groups and the promise of job opportunities and improved economic well-being for lower income groups. As existing coastal urban nodes expand development “shifts” to less developed areas and places increasing pressure on the surrounding natural environment. This article considers the coastal zone of two municipalities in the Eastern Cape, South Africa, with similar environmental characteristics but disparate socioeconomic and governance histories. It identifies and integrates the drivers of development and land use change in the coastal zone of these municipalities by means of an adapted Driver-Pressure-State-Impact-Response (DPSIR) Framework. Development and land use change are driven by a combination of social, economic, and legislative factors that need to be considered for future management and planning in this unique dynamic system.     

An Assessment of Integrated Coastal Management Governance and Implementation Using the DPSIR Framework: KwaZulu-Natal,South Africa

Coastal areas are under increasing pressure driven by demands for coastal space, primarily though population growth, in migration and the need for space for socioeconomic activities. The pressures and associated changes to the coastal environment need to be managed to ensure long-term sustainability. South Africa has enacted an Integrated Coastal Management Act (ICM Act) to facilitate dedicated management of its coastal environment. The implementation has been met with a number of challenges, primarily relating to financial and human capacity constraints, particularly at the local government level. Given that the ICM Act devolves powers to local government, it is imperative that implementation challenges be addressed. This paper focuses on KwaZulu-Natal, one of four South African coastal regions, which is a renowned tourist destination and home to 11.1 million people (Statistics South Africa 2015 Statistics South Africa. 2015. Mid-Year Population Estimates. Statistical release P0302. Pretoria, South Africa: Statistics South Africa. [Google Scholar]). This paper considers the state of coastal management, as well as implementation challenges being experienced at a local governance level, and highlights ways to address these. Data were acquired through questionnaire surveys and semistructured interviews. The Drivers-Pressures-State-Impact-Response (DPSIR) framework was used to identify relevant ICM issues and concerns and develop potential actions for improving the implementation of coastal management activities and the ICM Act. In the assessment of the ICM governance and implementation to date, a key concern identified was a general lack of coastal management knowledge among officials. It was specifically identified that knowledgeable management and capacity-building required championing from the provincial government in order to more efficiently and effectively implement the objectives of the ICM Act through an improved understanding of the coastal environment, its functioning and management.     

Do new sources of traffic data make the application of Chaos Theory to traffic management a realistic possibility?

Current signal systems for managing road traffic in many urban areas around the world lack a coordinated approach to detecting the spatial and temporal evolution of congestion across control regions within city networks. This severely inhibits these systems’ ability to detect reliably, on a strategic level, the onset of congestion and implement effective preventative action. As traffic is a time-dependent and non-linear system, Chaos Theory is a prime candidate for application to Urban Traffic Control (UTC) to improve congestion and pollution management. Previous applications have been restricted to relatively uncomplicated motorway and inter-urban networks, arguably where the associated problems of congestion and vehicle emissions are less severe, due to a general unavailability of high-resolution temporal and spatial data that preserve the variability in short-term traffic patterns required for Chaos Theory to work to its full potential. This paper argues that this restriction can now be overcome due to the emergence of new sources of high-resolution data and large data storage capabilities. Consequently, this opens up the real possibility for a new generation of UTC systems that are better able to detect the dynamic states of traffic and therefore more effectively prevent the onset of traffic congestion in urban areas worldwide.