Erosion and tourism infrastructure in the coastal zone: Problems, consequences and management

The importance of coastal zones to the tourism industry and the need to protect such resources is not only vital to the economy of nations but presents a growing dilemma for many localities and regions. Beaches have become synonymous with tourism and with current predictions of climate change and sea level rise; they are under significant threat of erosion worldwide. From an assessment of the effects of erosion, including evaluation of impacts on coastal destinations and tourism development, the consequences for global tourism business are projected. An analysis of hard and soft engineering responses showed that coastal protection measures should be linked to physical processes whilst management strategies included a case study proposal for beach nourishment, in response to the erosion of a tourist beach. Integrated Coastal Zone Management is justified as a tool for managing coastal resources and accommodating increasing pressures from tourism whilst strategies are recommended to ameliorate projected impacts

Beach erosion and marine aggregate dredging: a question of evidence?

Coastal erosion is a global problem and a major concern for European Union Member States. In the UK, marine aggregate dredging is considered by many to be responsible for coastal loss and campaigns based on the ‘precautionary principle’ have been mounted to halt extraction. Two South Wales, UK coastal areas, where critical beach loss has been associated with dredging activities, were monitored to assess morphological change. In five years of beach monitoring along the Penarth coastline (September 1997 to September 2002) and six years monitoring Port Eynon and Horton beaches (January 2001 to October 2007), no qualitative or quantitative causal link was found between marine aggregate dredging and beach erosion. Conversely, many qualitative and quantitative relationships were established between beach erosion and forcing agents such as water level, wind and waves. Results from Port Eynon and Horton showed significant temporal variations in beach level and on-shore/offshore sediment movement was seen as significant in beach formation processes. At Penarth, changing wind direction and increased easterly storms were most significant. Furthermore, there were indications of recognised causes of coastal erosion such as increased water levels, storms and anthropogenic construction. Therefore, morphological changes on a relatively short timescale can be clearly attributed to influences other than marine aggregate dredging. Potential future work includes regular monitoring and analysis of shoreline changes in areas adjacent to dredging sites together with concurrent bathymetric surveys. As well as being a strategic approach, it would address stakeholder concern and reduce conflict

A Comparative Assessment of Floating and Submerged Sensor Network Deployments for Monitoring Underwater Sediment Transport Processes

Wireless Sensor Networks (WSNs) are a pioneering technology in many environmental monitoring applications owing to their ability to be deployed for long periods of time in locations that cannot be reached manually. One such use-case is the monitoring of underwater sediment transport, a process that plays a significant role in coastal erosion. Previous examples of WSNs deployed for this purpose have been in the form of underwater sensor networks (UWSNs), which have a number of shortcomings from both a practical and technical viewpoint. As such, this paper provides a comparative assessment of UWSNs and an alternative deployment approach of floating echosounding sensor networks for the purpose of monitoring underwater sediment transport

Mesoscale Morphological Change, Beach Rotation and Storm Climate Influences along a Macrotidal Embayed Beach

Abstract: Cross-shore profiles and environmental forcing were used to analyse morphological change of a headland bay beach: Tenby, West Wales (51.66 N; −4.71 W) over a mesoscale timeframe (1996–2013). Beach profile variations were attuned with longer term shoreline change identified by previous research showing southern erosion and northern accretion within the subaerial zone and were statistically significant in both sectors although centrally there was little or no significance. Conversely a statistically significant volume loss was shown at all profile locations within the intertidal zone. There were negative phase relationships between volume changes at the beach extremities, indicative of beach rotation and results were statistically significant (p < 0.01) within both subaerial (R2 = 0.59) and intertidal (R2 = 0.70) zones. This was confirmed qualitatively by time-series analysis and further cross correlation analysis showed trend reversal time-lagged associations between sediment exchanges at either end of the beach. Wave height and storm events displayed summer/winter trends which explained longer term one directional rotation at this location. In line with previous regional research, environmental forcing suggests that imposed changes are influenced by variations in southwesterly wind regimes. Winter storms are generated by Atlantic southwesterly winds and cause a south toward north sediment exchange, while southeasterly conditions that cause a trend reversal are generally limited to the summer period when waves are less energetic. Natural and man-made embayed beaches are a common coastal feature and many experience shoreline changes, jeopardising protective and recreational beach functions. In order to facilitate effective and sustainable coastal zone management strategies, an understanding of the morphological variability of these systems is needed. Therefore, this macrotidal research dealing with rotational processes across the entire intertidal has significance for other macrotidal coastlines, especially with predicted climate change and sea level rise scenarios, to inform local, regional and national shoreline risk management strategies. Keywords: mesoscale morphological change; beach rotation; storm climat

Two novel proteins, TtpB2 and TtpD2, are essential for iron transport in the TonB2 system of Vibrio vulnificus

In gram‐negative bacteria, energy‐dependent active transport of iron‐bound sub‐ strates across the outer membrane is achieved through the TonB systems of proteins. Three TonB systems have been identified in the human pathogen Vibrio vulnificus. The TonB1 system contains three proteins: TonB1, ExbB1, and ExbD1. Both the TonB2 and TonB3 systems have been shown to also contain a fourth protein, TtpC2 and TtpC3, respectively. Here, we report and begin to characterize two additional proteins in the TonB2 and TonB3 systems: TtpB and TtpD. Both TtpB2 and TtpD2 are absolutely required for the function of the TonB2 system in V. vulnificus. However, although both TtpB3 and TtpD3 in the TonB3 system are related to the proteins in the TonB2 system, neither are active in iron transport. All six protein components of the TonB2 system—TonB2, ExbB2, ExbD2, TtpB2, TtpC2, and TtpD2—are essential for the uptake of both endogenously produced iron‐bound siderophores and exog‐ enous siderophores produced from other organisms. Through complementation, we have shown that V. vulnificus is capable of using different TtpD2 proteins from other Vibrio species to bring in multiple siderophores. In contrast, we also demonstrate that TtpB2 must come from V. vulnificus, and not other species within the genus, to complement mutations in the TonB2 system

Wireless Sensor Networks for monitoring underwater sediment transport

Monitoring of the coastline and coastal processes, in particular sediment movement, is vital to ensure that erosion response is appropriate given the dynamic nature of coastal systems. This should take place regularly over long periods and it is important that data are collected from submerged portions of the littoral zone, as well as the visible beach. This highlights two limitations in existing coastal monitoring techniques: 1. they require largely manual operation and 2. are limited to the visible beach, which results in an incomplete picture of what is happening in the coastal zone. Due to the current difficulties in gathering data beneath the sea surface, this paper reviews wireless sensor network (WSN) technology as a means to overcome these limitations. Analysis showed that WSNs are a promising technology for coastal monitoring, not only in terms of overcoming limitations, but also in terms of cost, safety, and the size of areas they are able to monitor. Previous work using WSNs in this environment is somewhat limited, especially as most current methods are largely limited to the visible beach, and do not consider submerged areas of the coastal zone. From consideration of the physical environment, geological and geographical processes, and informed by advances in technology, research gaps are identified, discussed and evaluated to provide strategies for implementation of WSNs to monitor sediment transport

Crustal-Lithospheric structure, geological evolution and continental extrusion of Tibet

Abstract HKT-ISTP 2013 A

The Australia Telescope 20GHz (AT20G) Survey: analysis of the extragalactic source sample

The Australia Telescope 20 GHz (AT20G) survey is a blind survey of the whole Southern sky at 20 GHz with follow-up observations at 4.8, 8.6, and 20 GHz carried out with the Australia Telescope Compact Array (ATCA). In this paper we present an analysis of radio spectral properties in total intensity and polarisation, sizes, optical identifications, and redshifts of the sample of the 5808 extragalactic sources in the survey catalogue of confirmed sources over the whole Southern sky excluding the strip at Galactic latitude |b|<1.5deg. The sample has a flux density limit of 40 mJy. Completeness has been measured as a function of scan region and flux density. Averaging over the whole survey area the follow-up survey is 78% complete above 50mJy and 93% complete above 100mJy. 3332 sources with declination <-15deg have good quality almost simultaneous observations at 4.8, 8.6, and 20GHz. The spectral analysis shows that the sample is dominated by flat-spectrum sources. The fraction of flat-spectrum sources decreases from 81% for 20GHz flux densities S>500mJy, to 60% for S<100mJy. There is also a clear spectral steepening at higher frequencies with the median spectral index decreasing from -0.16 between 4.8 and 8.6GHz to -0.28 between 8.6 and 20GHz. Simultaneous observations in polarisation are available for all the sources at all the frequencies. 768 sources have a good quality detection of polarised flux density at 20GHz; 467 of them were also detected in polarisation at 4.8 and/or at 8.6GHz so that it has been possible to compare the spectral behaviour in total intensity and polarisation. We have found that the polarised fraction increases slightly with frequency and decreases with flux density. Cross matches and comparisons have been made with other catalogues at lower radio frequencies, and in the optical, X-ray and gamma-ray bands. Redshift estimates are available for 825 sources.Comment: 15 pages, 16 figures, accepted for publication in MNRA

Systematic Review and Meta-Analysis of Randomised Trials to Ascertain Fatal Gastrointestinal Bleeding Events Attributable to Preventive Low-Dose Aspirin: No Evidence of Increased Risk.

BACKGROUND: Aspirin has been shown to lower the incidence and the mortality of vascular disease and cancer but its wider adoption appears to be seriously impeded by concerns about gastrointestinal (GI) bleeding. Unlike heart attacks, stroke and cancer, GI bleeding is an acute event, usually followed by complete recovery. We propose therefore that a more appropriate evaluation of the risk-benefit balance would be based on fatal adverse events, rather than on the incidence of bleeding. We therefore present a literature search and meta-analysis to ascertain fatal events attributable to low-dose aspirin. METHODS: In a systematic literature review we identified reports of randomised controlled trials of aspirin in which both total GI bleeding events and bleeds that led to death had been reported. Principal investigators of studies in which fatal events had not been adequately described were contacted via email and asked for further details. A meta-analyses was then performed to estimate the risk of fatal gastrointestinal bleeding attributable to low-dose aspirin. RESULTS: Eleven randomised trials were identified in the literature search. In these the relative risk (RR) of 'major' incident GI bleeding in subjects who had been randomised to low-dose aspirin was 1.55 (95% CI 1.33, 1.83), and the risk of a bleed attributable to aspirin being fatal was 0.45 (95% CI 0.25, 0.80). In all the subjects randomised to aspirin, compared with those randomised not to receive aspirin, there was no significant increase in the risk of a fatal bleed (RR 0.77; 95% CI 0.41, 1.43). CONCLUSIONS: The majority of the adverse events caused by aspirin are GI bleeds, and there appears to be no valid evidence that the overall frequency of fatal GI bleeds is increased by aspirin. The substantive risk for prophylactic aspirin is therefore cerebral haemorrhage which can be fatal or severely disabling, with an estimated risk of one death and one disabling stroke for every 1,000 people taking aspirin for ten years. These adverse effects of aspirin should be weighed against the reductions in vascular disease and cancer

The Australia Telescope 20 GHz Survey: The Source Catalogue

We present the full source catalogue from the Australia Telescope 20 GHz (AT20G) Survey. The AT20G is a blind radio survey carried out at 20 GHz with the Australia Telescope Compact Array (ATCA) from 2004 to 2008, and covers the whole sky south of declination 0 deg. The AT20G source catalogue presented here is an order of magnitude larger than any previous catalogue of high-frequency radio sources, and includes 5890 sources above a 20 GHz flux-density limit of 40 mJy. All AT20G sources have total intensity and polarisation measured at 20 GHz, and most sources south of declination -15 deg also have near-simultaneous flux-density measurements at 5 and 8 GHz. A total of 1559 sources were detected in polarised total intensity at one or more of the three frequencies. We detect a small but significant population of non-thermal sources that are either undetected or have only weak detections in low-frequency catalogues. We introduce the term Ultra-Inverted Spectrum (UIS) to describe these radio sources, which have a spectral index alpha(5, 20) > +0.7 and which constitute roughly 1.2 per cent of the AT20G sample. The 20 GHz flux densities measured for the strongest AT20G sources are in excellent agreement with the WMAP 5-year source catalogue of Wright et al. (2009), and we find that the WMAP source catalogue is close to complete for sources stronger than 1.5 Jy at 23 GHz.Comment: 21 pages, accepted for publication in MNRA