Costs and benefits to European shipping of ballast-water and hull-fouling treatment: Impacts of native and non-indigenous species

Maritime transport and shipping are impacted negatively by biofouling, which can result in increased fuel consumption. Thus, costs for fouling reduction can be considered an investment to reduce fuel consumption. Anti-fouling measures also reduce the rate of introduction of non-indigenous species (NIS). Further mitigation measures to reduce the transport of NIS within ballast water and sediments impose additional costs. The estimated operational cost of NIS mitigation measures may represent between 1.6% and 4% of the annual operational cost for a ship operating on European seas, with the higher proportional costs in small ships. However, fouling by NIS may affect fuel consumption more than fouling by native species due to differences in species’ life-history traits and their resistance to antifouling coatings and pollution. Therefore, it is possible that the cost of NIS mitigation measures could be smaller than the cost from higher fuel consumption arising from fouling by NIS.

Assessing the Impact of Shipping Vessel Noise on Humpback Whales

The ocean is a hub of noise. Bioacoustic noise, noise from precipitation and wind, and noise from oceanic shelf slides and other geologic processes have occurred consistently as marine species have evolved over time. However, with the discovery of oceanic oil and gas reserves, submarine systems, ship propulsion and the emergence of global trade, anthropogenic sources of sound have added significant quantities of sound to the oceanic system. Shipping has been found to be the largest input of low-frequency anthropogenic noise and Humpback Whales (Megaptera novaengliae), known to be the most vocal marine species, have an auditory sensitivity that falls within the range of frequencies emitted by shipping vessels. As Humpback Whales are heavily dependent on vocalizations, for reasons relatively unconfirmed, a better understanding of why they sing and how their communication is being impacted by vessel noise is critical. Evaluating existing literature both on Humpback behavior and communication, the mechanics of their communication, sound emissions from modern ships, oceanic sound transmission, and studies regarding Humpback's exposure to other sources of low-frequency anthropogenic noise, it is clear that more research is needed to draw any causational conclusions between vessel noise and detrimental impacts on Humpback Whales. With a projected increase in global consumption and vessel traffic, there is an urgent need for further research exploring shipping noise impacts and behavioural alterations of Humpbacks. Existing research has shown changes in Humpback communication when exposed to low-frequency sonar noise, however few studies have been conducted on their communication when in close proximity to shipping vessels. In order for the impacts to be properly assessed, preliminary understanding of humpback communication, their auditory thresholds and more studies between vessel noise exposure and Humpback Whale behavior must be conducted.

Notas sobre el "primum cognitum" en Cayetano y su vínculo con la metafísica

Cayetano tuvo un papel protagónico en los debates intelectuales de su época (s. XVI), destacándose como un auténtico adalid del tomismo; inclusive muchas de sus tesis pasaron a formar parte de tal doctrina, las cuales –a veces matizadas y otras no tanto– perviven hasta nuestros días. Entre los diversos temas que afrontó se destaca su particular noción de primum cognitum. Aquí, partimos del hecho de que la tradición tomista no ha visto mayores inconvenientes en equiparar lo que entienden Cayetano y el Aquinate por el ens primo cadit; empero nosotros estamos en condiciones de afirmar que tal equiparación al menos es problemática. En este sentido, nos ocuparemos de realizar un primer acercamiento al tema del ente primer conocido cayetaniano para intentar mostrar su real significado. Asimismo, procuraremos ver, ayudados por los aportes de algunos estudiosos contemporáneos –en especial el de Lawrence Dewan–, hasta qué punto tal noción se corresponde o no con los desarrollos teóricos de Tomás de Aquino, sobre todo con el vínculo entre el primer conocido y el ente como objeto de la metafísica.