Search results
Results From The WOW.Com Content Network
The RBE is given by . Typically the evaluation of relative biological effectiveness is done on various types of living cells grown in culture medium , including prokaryotic cells such as bacteria , simple eukaryotic cells such as single celled plants, and advanced eukaryotic cells derived from organisms such as rats .
The oxygen enhancement ratio (OER) or oxygen enhancement effect in radiobiology refers to the enhancement of therapeutic or detrimental effect of ionizing radiation due to the presence of oxygen. This so-called oxygen effect [ 1 ] is most notable when cells are exposed to an ionizing radiation dose .
This figure illustrates the typical change in the relative radiosensitivity for a biological effect such as cell death when exposed to radiations of low ionizing density (e.g. x-rays). The hyperbolic relationship shown has a maximum OER of 2.70 for 100% oxygen (at 760 mmHg), with a half-range OER value at 4.2 mmHg or 0.55% of oxygen.
The rem and millirem are CGS units in widest use among the U.S. public, industry, and government. [4] However, the SI unit the sievert (Sv) is the normal unit outside the United States, and is increasingly encountered within the US in academic, scientific, and engineering environments, and have now virtually replaced the rem. [5]
The George W. Bush administration put the Continuity of Operations plan into effect for the first time directly following the September 11 attacks.Their implementation involved a rotating staff of 75 to 150 senior officials and other government workers from every federal executive department and other parts of the executive branch in two secure bunkers on the East Coast.
The Government Performance and Results Act of 1993 (GPRA) (Pub. L. 103–62) is a United States law enacted in 1993, [1] one of a series of laws designed to improve government performance management. The GPRA requires agencies to engage in performance management tasks such as setting goals, measuring results, and reporting their progress.
While OER seem well placed to bring down total expenditures, they are not cost-free. New OER can be assembled or simply reused or repurposed from existing open resources. This is a primary strength of OER and, as such, can produce major cost savings. OER need not be created from scratch.
The UNESCO 2012 Paris OER Declaration, otherwise known as the Paris declaration on Open Educational Resources, is a declaration urging governments to promote the use of open educational resources (OERs) and calling for publicly funded educational materials to be released in a freely reusable form.