61 research outputs found
Maritime Operations and Emergency Preparedness in the Arctic–Competence Standards for Search and Rescue Operations Contingencies in Polar Waters
Emergencies on large passenger ships in the remote High North may lead to a mass rescue operation with a heavy strain on the emergency preparedness systems of the Arctic countries. This study focuses on the need for competencies related to large-scale Search and Rescue operations (SAR operations) amongst the shipping companies, vessels and governments involved. A SAR operation is the activity related to finding and rescuing people in distress. Several international standards, in particular the conventions by the International Maritime Organization (IMO), provide direction for education and training of seafarers and rescue staff. This study elaborates on the operational competence requirements for key personnel involved in large scale SAR operations. Findings from real SAR incidents and exercises provide in-depth understanding on the operational challenges. The chapter gives directions for competence programs, beyond obligatory international standards, and recommendations for further research
A Laboratory Study of Nonlinear Surface Waves on Water
This paper describes an experimental investigation in which a large number of water waves were focused at one point in space and time to produce a large transient wave group. Measurements of the water surface elevation and the underlying kinematics are compared with both a linear wave theory and a second-order solution based on the sum of the wave-wave interactions identified by Longuet-Higgins & Stewart (1960). The data shows that the focusing of wave components produces a highly nonlinear wave group in which the nonlinearity increases with the wave amplitude and reduces with increasing bandwidth. When compared with the first- and second-order solutions, the wave-wave interactions produce a steeper wave envelope in which the central wave crest is higher and narrower, while the adjacent wave troughs are broader and less deep. The water particle kinematics are also strongly nonlinear. The accumulated experimental data suggest that the formation of a focused wave group involves a significant transfer of energy into both the higher and lower har¬monics. This is consistent with an increase in the local energy density, and the development of large velocity gradients near the water surface. Furthermore, the nonlinear wave-wave interactions are shown to be fully reversible. However, when compared to a linear solution there is a permanent change in the relative phase of the free waves. This explains the downstream shifting of the focus point (Longuet-Higgins 1974), and appears to be similar to the phase changes which result from the nonlinear interaction of solitons travelling at different velocities (Yuen & Lake 1982)
The Complete Genome Sequence of ‘Candidatus Liberibacter solanacearum’, the Bacterium Associated with Potato Zebra Chip Disease
Zebra Chip (ZC) is an emerging plant disease that causes aboveground decline of
potato shoots and generally results in unusable tubers. This disease has led to
multi-million dollar losses for growers in the central and western United States
over the past decade and impacts the livelihood of potato farmers in Mexico and
New Zealand. ZC is associated with ‘Candidatus
Liberibacter solanacearum’, a fastidious alpha-proteobacterium that is
transmitted by a phloem-feeding psyllid vector, Bactericera
cockerelli Sulc. Research on this disease has been hampered by a
lack of robust culture methods and paucity of genome sequence information for
‘Ca. L. solanacearum’. Here we present the
sequence of the 1.26 Mbp metagenome of ‘Ca. L.
solanacearum’, based on DNA isolated from potato psyllids. The coding
inventory of the ‘Ca. L. solanacearum’ genome was
analyzed and compared to related Rhizobiaceae to better
understand ‘Ca. L. solanacearum’ physiology and
identify potential targets to develop improved treatment strategies. This
analysis revealed a number of unique transporters and pathways, all potentially
contributing to ZC pathogenesis. Some of these factors may have been acquired
through horizontal gene transfer. Taxonomically, ‘Ca. L.
solanacearum’ is related to ‘Ca. L.
asiaticus’, a suspected causative agent of citrus huanglongbing, yet many
genome rearrangements and several gene gains/losses are evident when comparing
these two Liberibacter. species. Relative to ‘Ca. L.
asiaticus’, ‘Ca. L. solanacearum’ probably
has reduced capacity for nucleic acid modification, increased amino acid and
vitamin biosynthesis functionalities, and gained a high-affinity iron transport
system characteristic of several pathogenic microbes
Effectiveness of the Polar Code Training of Cruise Liner Crew for Evacuation in the Arctic and Antarctic
In the past decades, we have seen a prolific increase in Polar Cruise Tourism, and thereby, more humans are able to visit the Polar Regions. As a result of this, the IMO implemented the Polar Code in 2017 to better prepare seafarers in polar waters in order to ensure maritime safety. Several researches have been carrying out work, after the Polar Code came into force, to evaluate its realization concerning the harsh climatic conditions of the Arctic and Antarctic. Based on the Polar Code requirements, the crew’s preparedness for evacuation and survival in negative temperatures due to remoteness, is somewhat ambiguous. Also, the use of safety equipment in the polar climate still is in the discussion, whether sufficient or not. This paper investigates the cruise crew’s preparedness for an evacuation in the Arctic and Antarctic, according to the Polar Code. Here, gaps in the existing Polar Code Basic and Advanced Training modules were identified with respect to evacuation needs. Questionnaires and interviews were used as the research method to evaluate the insights of the potential target audiences. The study findings were analyzed and reveal the Polar Code’s ineffectiveness with respect to educating the cruise crew for an evacuation, along with the lack of requirement to passenger survival training. This study recommends specific evacuation training for all the cruise crew members based on the actual needs and, subsequently, the need for improvement in the Polar Code training modules. It also proposes survival training modules for cruise passengers to be developed, for evacuation of a vessel in the Arctic and Antarctic
The influence of the composition of water on the results of accelerated aging resistance testing of low voltage subsea cables insulation
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