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Continuous versus pulsed origination and extinction and biozones

Trammer J.

Acta Geologica Polonica

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2014

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Vol. 64, no. 4

361--366

EN

The count of biozones as an approximate measure of the origination and extinction rates of index taxa (mostly species) is proposed. The mean number of extinctions of these taxa per m.y. is 1.136 (Palaeozoic mean 0.902, Mesozoic mean 1.680, Cenozoic mean 0.789). In contrast with the majority of taxa, the originations and extinctions of index taxa, as well as of other taxa belonging to biostratigraphically important systematic groups, seems to be continuous.

2

The late Silurian-Middle Devonian long-term eustatic cycle as a possible control on the global generic diversity dynamics of bivalves and gastropods

Ruban Dmitry A.

Geologos

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2013

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Vol. 19, No. 3

193--200

EN

A long-term eustatic cycle (fall and subsequent rise of the global sea level) embraced the late Silurian-Middle Devonian time interval. Potentially, these sea-level changes could drive global biodiversity. The stratigraphic ranges of 204 bivalve genera and 279 gastropod genera included into the famous Sepkoski database allow reconstructing changes in the total diversity and the number of originations and extinctions of these important groups of marine benthic macro- -invertebrates during this interval. None of the recorded parameters coincided with the long-term global sea-level cycle. It cannot be not excluded, however, that the global sea-level changes did not affect the regions favourable for bivalve and gastropod radiation because of regional tectonic mechanisms; neither can it be excluded that the eustatic control persisted together with many other extrinsic and intrinsic controls. Interestingly, the generic diversity of gastropods increased together with a cooling trend, and vice versa. Additionally, the Ludlow, Eifelian, and Givetian biotic crises affected, probably, both fossil groups under study. There was also a coincidence of the relatively high bivalve generic diversity, initial radiation of gastropods and the entire biota, and the diversification of brachiopods with the Early Devonian global sea-level lowstand, and this may be interpreted as evidence of a certain eustatic control on the marine biodiversity.

3

Development of ship technical requirements by international maritime organization

Tarełko W.

Journal of Polish CIMAC

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2012

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Vol. 7, no 2

205-216

EN

The International Maritime Organization (IMO) is a specialized agency of the United Nations deals with international shipping. Its primary purpose is to develop and maintain a comprehensive regulatory framework for shipping and its remit today includes: safety, environmental concerns, legal matters, etc. In order to achieve its objectives, the IMO has promoted the adoption of some documents such as conventions, codes and recommendations concerning maritime safety, the prevention of pollution and related matters. Many of these documents include the ship safety requirements. In order to apply them to ships, they first should be generated, prepared and recorded. This paper deals exactly with the origins of ship safety requirements. Depending on the safety requirement origins, the IMO actions can get the reactive or proactive character. Reactive actions are used in response to a particular situation being observed, whereas proactive actions involve acting in advance of a future situation, rather than just reacting. It means taking control and making things happen rather than just adjusting to a situation or waiting for something to happen. In the paper, development of safety technical requirements for ships is presented based on experience of the author as a chairperson of Polish department for Subcommittee of Ship and Equipment Design (DE) of International Maritime Organization.