Note on the "Natural Radioactivity of Rhenium"

Assessment of the 187Re decay constant by cross calibration of Re–Os molybdenite and U–Pb zircon chronometers in magmatic ore systems

“…Direct counting experiments Sugarman and Richter (1948) Suttle and Libby (1954) Watt and Glover (1962) Wolf and Johnston (1962) Brodzinski andConway (1965) Naldrett (1984) 1.53 ± 0.08 · 10 À11 a À1…”

“…Many studies used direct counting experiments and determined k 187 Re values between 2.31 · 10 À11 and 1.39 · 10 À13 a À1 (Sugarman and Richter, 1948;Suttle and Libby, 1954;Watt and Glover, 1962;Wolf and Johnston, 1962;Brodzinski and Conway, 1965;Naldrett, 1984;Ashktorab et al, 1993;Alessandrello et al, 1999;Galeazzi et al, 2001;Arnaboldi et al, 2003) ( Table 1). The precision of these studies has been improved by mircocalorimetric determinations (Ashktorab et al, 1993;Alessandrello et al, 1999;Galeazzi et al, 2001;Arnaboldi et al, 2003), but even these modern methods yield results with uncertainties at the several percent level (Galeazzi et al, 2001).…”

Charter School Funding Issues

“…Indeed, this new requirement might cause many districts to decide to call a halt to chartering, even though California law is supposed to make it difficult for districts to refuse a charter sought by any applicant with reasonably sensible plans for its school. 27 In any event, this problem remains a difficult one for charter schools in other states Despite the points just noted, it should also be appreciated that sometimes charter schools have certain financial advantages. For example, in states that provide uniform per pupil funding for charter schools at all grade levels, charter schools have tended to be created to serve elementary, not high school, pupils because younger children are traditionally cheaper to educate.…”