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2 1 e with a calculated slope equal to 0.0295V instead of 0.0885V. Similarly, the defect Vcd' would give a slope equal to 0.059V.The hypothesis can be made that the plateaus observed in the titration curves are due to impurities introduced in the sample, either during the cadmium electrodeposition or during the formation of the sulfide layer. Particularly, the samples could contain cadmium oxide and/or sodium sulfide. As sulfide and oxide species are similar the presence of dissolved cadmium oxide (i.e., the replacement of a sulfur atom Ss by an oxygen atom Os) could only slightly modify the cadmium sulfide properties. Sodium sulfide is an ionic compound which dissolves in CdS with more difficulty. It is also possible that the remaining sodium sulfide is transformed into cadmium sulfide during the oxidation of the cadmium in excess. However, as it stands now, it is not possible to state precisely what kind of impurities are involved. But the obtained results show that electrochemical analysis is a possible method of studying cadmium sulfide and, more generally, semi-conductors having a possible deviation from stoichiometry.

to chance. The models also suggested that fledgeling success increased in seasons that were slightly cooler and wetter than average. Modelling studies were also carried out on a historical dataset of penguin population variables in the 1930s. It was found that the population tended to increase in seasons that were warmer and drier than average. Average temperatures have risen and average precipitation levels have become highly variable in the study area during this time. Therefore, long term climate change in general, rather than the El Nino-Southern Oscillation events in particular, could be among the underlying causes of gradual decline in yellow-eyed penguin numbers.Keywords Megadyptes antipodes; yellow-eyed penguin population variables; climate variables; computer models; causal link; climate change Abstract Since 1980, the yellow-eyed penguin Megadyptes antipodes has had three seasons of poor breeding success or low adult survival. Causes for poor seasons are not identified but could be related to climate -in particular, the El Nino-Southern Oscillation event, which affects ocean currents and climate over the penguins' range. We carried out an exploratory analysis to determine whether fluctuations in penguin population variables were correlated with fluctuations in climate variables. Population variables across breeding areas showed consistently strong correlations with rainfall and sea surface temperature. We modelled changes in climate variables and penguin population variables to test whether the effect could be explained as a chance correlation. Investigations using these models indicated that the observed relationship was unlikely to have been due

Multiple offshore Arctic fields have been developed over the past three decades and the world demand for oil and gas will continue to drive hydrocarbon development in Arctic and sub-Arctic environments. Arctic pipelines are used for the safe and economic transportation of hydrocarbons. While pi pelines are designed not to leak, excessive strains due to the effect s of ice gouging, strudel scour, frost heave and p ermafrost thaw settlement along with other loading and failure mechanisms (i.e. corrosion, third party damage) could result in a leak. Failure to detect leaks in a timely manner could have severe safety, environmental, and economic impacts. Large leaks can easily be detected, but small chronic leaks may go undetected for a period of time, especially when pipelines are buried in remote locations or under seasonal ice cover.First, this paper reviews existing Leak Detection System (LDS) technologies for their potential use on Arctic and sub-Arctic pipelines. The technology evaluation based on regulatory requirements and functional criteria suggests that Fiber O ptic Cable (FOC) distributed sensing systems have a high pote ntial to be use d on Arcti c pipelines. Distributed sensing FOC can b e used to detect and locate leakages. Pipeline leakage would gen erate a local change in te mperature. These thermal anomalies can be captured by FOC Distributed Temperature Sensing (DTS) systems with good spatial and temporal resolution. Similarly, the acoustic signature generated by leaking fluid can be detected using FOC Distributed Acoustic Sensing (DAS) systems. Inelastic Brillouin and Raman backscattering principles are used for measuring temperature in DTS, whereas the Rayleigh backscattering principle is used for measuring acoustics in DAS. This paper presents information on a pplicable regulations, operating principles, optical budgets, system integration, sensor positioning, installation and maintenance assessment, technology status, risk an alysis using Failure Mode, Effec ts and Critic ality Analysis (FMECA) and field implementation challenges.