Activities observed in iridium after neutron bombardment. Remarks on a paper by H. H. Hennies and A. Flammersfeld
Recently Hennies and Flanunersfeld (Naturwissenschaften, 47: 11(1960)) reported ths observation of a new 47-sec activity produced by irradiating Ir powder with slowed-down neutrons. The activity was tentatively assigned to Ir/ sup 194//sup m/. Beta activities, previously ascribed to Ir/sup 192//sup m/, were reassigned to Ir/sup 194//sup m/. A repetition of the experiment on the bombardment of Ir/sup 193/ with slow neutrons (Phys. Rev. Lettens, 3: 4S(1959)) confirmed the previous conclusions and ruled out a 47-sec period in Ir/sup 192/ or Ir/sup 19 / 4>s. It was suggested that the Hennies and Flammersfeld results may be partly ascribed to a Rh impurity and partly to the effect of fast neutrons. (J.S.R.)
TRIPLE ISOMERISM IN Ir$sup 19$$sup 2$
In studying an iridium specimen irradiated for one month in the BNL Reactor and then allowed to cool, a gamma spectrum identical with Ir/sup 192g/ was obtained, but corresponding to a source strength of 2820 plus or minus 140 disintegrations per sec. As Ir/sup 192/ g is known to have a 1.45minute isomer, decaying mainly by a 58-kev isomeric (E3) transition to the 74-day ground state, it was concluded that the observed activity stems from a third, longer lived isomer of Ir/sup 192/. Afar various studies on the isomer a lower limit of T 1/2 > 5 yr was set. (W.D.M.)
Protecting Marine Biodiversity on the Continental Shelf Beyond 200 Nautical Miles
States are expending significant effort to chart the extent of their continental shelves where these extend beyond 200 nautical miles. As more is understood about marine biodiversity on the outer continental shelf, states may wish to regulate the use of biodiversity for the purposes of conservation or for future exploitation. This article identifies potential threats to marine biodiversity on the continental shelf, explores whether conservation is a legitimate purpose for exercising coastal state rights over the outer continental shelf under the Law of the Sea Convention, and considers the various legal rules that coastal states may use to protect marine biodiversity. The article concludes that the continental shelf regime is undesirably vague in some instances but that coastal states have a legal basis for taking action to regulate activities that impact the marine biodiversity of the outer continental shelf.