However, these studies are subject to several methodological limitations, including sample size, the limited ability to detect adverse events, loss to follow-up, exemption of vaccine recipients with previous adverse events, observational bias, and the absence of unvaccinated control groups.By 2000, some 425,976 US service members had received 1,620,793 doses of AVA. The IOM review (2000-2004)
In October 2000, a committee of the Institute of Medicine (IOM) of the National Academy of Sciences was asked by the US Congress to review AVA according to the best available evidence. It issued its study in March 2002. The IOM panel noted that human data on inhalational anthrax prevention is limited due to the natural low incidence of disease and that therefore animal model data are the best we are ever likely to have. Primates and rabbits were considered the best models for human disease. As regards vaccine effectiveness, "The committee finds that the available evidence from studies with humans and animals, coupled with reasonable assumptions of analogy, show that AVA as licensed is an effective vaccine for the protection of humans against anthrax, including inhalational anthrax, caused by all known or plausible engineered strains of B. anthracis." With regard to safety, "The committee found no evidence that people face an increased risk of experiencing life-threatening or permanently disabling adverse events immediately after receiving AVA, when compared with the general population.
Properties
Tallying is often referred to as "base 1", since only one mark – the tally itself – is needed. This is more formally referred to as a unary numeral system. Unlike base 2 or base 10, this is not a positional notation. Since the base 1 exponential function (1x) always equals 1, its inverse does not exist (which would be called the logarithm base 1 if it did exist). There are two ways to write the real number 1 as a recurring decimal: as 1.000..., and as 0.999.... 1 is the first figurate number of every kind, such as triangular number, pentagonal number and centered hexagonal number, to name just a few. In many mathematical and engineering problems, numeric values are typically normalized to fall within the unit interval from 0 to 1, where 1 usually represents the maximum possible value in the range of parameters. Likewise, vectors are often normalized into unit vectors (i.e., vectors of magnitude one), because these often have more desirable properties. Functions, too, are often normalized by the condition that they have integral one, maximum value one, or square integral one, depending on the application. Because of the multiplicative identity, if f(x) is a multiplicative function, then f(1) must be equal to 1. It is also the first and second number in the Fibonacci sequence (0 being the zeroth) and is the first number in many other mathematical sequences. The definition of a field requires that 1 must not be equal to 0. Thus, there are no fields of characteristic 1.