The Effect of Automation on Helicopter Crew Communication: A Low-Fidelity Investigation

Increasing levels of technology have changed the task of flying modern helicopter cockpits by allowing many crew functions to be performed automatically. This study attempted to understand the relation between automation and helicopter crew coordination. Twenty-eight helicopter pilots were assigned to two-person crews and asked to fly a simulated mission in either automated or manual conditions using a low-fidelity helicopter simulator. Communication was transcribed and coded into a nine-category content classification system by two trained raters. The inter-rater reliability was +.84. Results indicated that a higher frequency of total communications was demonstrated during manual flights. The interaction of Pilot Position by Automation Level was significant (p\u3c.05) for three of the communication content categories: Observations, Suggestions, Statements of Intent. The results are discussed in terms of their implications for communications and Crew Resource Management (CRM) training for crews flying advanced technology helicopters

Ingestion of Small-Bodied Zooplankton by Zebra Mussels (Dreissena polymorpha): Can Cannibalism on Larvae Influence Population Dynamics?

The zebra mussel Dreissena polymorpha established populations in western Lake Erie in 1986 and achieved densities exceeding 3.4 × 105 individuals∙m−2 during 1990. We assessed apparently incidental predation on Lake Erie and Erindale Pond zooplankton by adult mussels. Dreissena larvae and small rotifers (Polyarthra spp., Keratella spp., Trichocerca) sustained moderate to high predatory mortality whereas larger taxa (Bosmina, Scapholeberis) were invulnerable to predation. Larval Dreissena almost always sustain \u3e 99% mortality in European lakes. While mortality has been ascribed primarily to lack of suitable settling substrate and unfavourable environmental conditions, it may be confounded by larval predation by adults. We demonstrate using STELLA™-modelling that with a larval mortality rate of 99%, settled mussel densities observed in western Lake Erie during 1990 would not be achieved until at least 1994. A model that combines a lower rate (70%) of abiotic mortality with larval predation by adult mussels c..., Les populations de dreissena polymorphe (Dreissena polymorpha) déjà établies dans la partie ouest du lac Érié en 1986 atteignaient des densités supérieures à 3,4 × 105 individus par mètre carré au cours de 1990. Nous avons évalué Ta prédation du zooplancton du lac Érié et de l\u27étang Erindale par les dreissenas adultes. Les larves des dreissenas et les petits rotifères (Polyarthra spp., Keratella spp., Trichocerca) présentaient une mortalité par prédation variant de moyenne à élevée tandis que les plus gros taxons (Bosmima, Scapholeberis) résistaient à toute prédation. Les larves de Dreissena des lacs européeens présentent presque toujours un taux de mortalité supérieur à 99%. La mortalité a surtout été attribuée à l\u27absence d\u27un substrat de fixation adéquat et à des conditions environnementales défavorables, mais elle peut être confondue avec celle découlant de la prédation des larves par les adultes. Nous avons montré, à l\u27aide d\u27un modèle STELLAmd, que les densités de dreissenas fixées notées en 1990 n\u27..

Acineta nitocrae: A new suctorian epizooic on nonindigenous harpacticoid copepods, Nitocra hibernica and N. incerta, in the Laurentian Great Lakes

Acineta nitocrae, a suctorian ciliate previously known from Ukraine, was discovered in western Lake Erie in October 1997 and in the Detroid in May 1999. Idividuals were found inhabiting the body surface of Nitocra hibernica and N. incerta, nonindigenous harpacticoid copepods

Possible Ballast Water Transfer of Lionfish to the Eastern Pacific Ocean

The Indo-Pacific Red Lionfish was first reported off the Florida coast in 1985, following which it has spread across much of the SE USA, Gulf of Mexico, and Caribbean Sea. Lionfish negatively impact fish and invertebrate assemblages and abundances, thus further spread is cause for concern. To date, the fish has not been reported on the Pacific coast of North or Central America. Here we examine the possibility of ballast water transfer of lionfish from colonized areas in the Atlantic Ocean to USA ports on the Pacific coast. Over an eight-year period, we documented 27 commercial vessel-trips in which ballast water was loaded in colonized sites and later discharged untreated into Pacific coast ports in the USA. California had the highest number of discharges including San Francisco Bay and Los Angeles-Long Beach. A species distribution model suggests that the probability of lionfish establishment is low for the western USA, Colombia and Panama, low to medium for Costa Rica, Nicaragua, El Salvador and Guatemala, medium to high for mainland Ecuador, and very high for western Mexico, Peru and the Galapagos Islands. Given the species’ intolerance of freshwater conditions, we propose that ballast water exchange be conducted in Gatún Lake, Panama for western-bound vessels carrying ‘risky’ ballast water to prevent invasion of the eastern Pacific Ocean

Relationship between nitrate reductase and nitrate uptake in phytoplankton in the Peru upwelling region

Nitrate reductase (NR) activity and 15NO3‒ uptake in phytoplankton were compared under different environmental conditions on two cruises in the upwelling region off Peru. The NR activity and NO3‒ uptake rates responded differently to light and nutrients and the differences led to variations in the uptake; reductase ratio. Analysis of these variations suggests that the re-equilibration time of the two processes in response to environmental perturbation is an important source of variability. The nitrate uptake system responds faster than the nitrate reductase system. Considering these differences in response time, the basic differences in the two processes, and the differences in their measurement, we conclude that the NR activity measures the current nitrate-reducing potential, which reflects NO3‒ assimilation before the sampling time, while 15NO3‒ uptake measures NO3‒ assimilation in the 6-h period following sampling. Thus, considering the sampling time as a point of reference, the former is a measure of the past and the latter is a measure of the futureFinancial support for this work was provided by the office of IDOE under NSF grants OCE-7600136 and OCE-7727006 to R. C. Dugdale, grants OCE-7523718, OCE-7800610, and OCE-801 1187 to T. T. Packard, and grant OCE-8O11216 to D. BlascoPeer reviewe