Twenty five years is both a very long time and a very short time. The OPS has seen many innovations— in technique as well as technology. At the same time, some things seem like they won't ever change. Our Society was conceived by Johnny Justice, Jr. (in the Spring of 1969 during a meeting in Sarasota, Florida); and Johnny is still a very active member! This paper is a reminiscence. Each of the ...

During the last twenty-five years, the contextual interference effect has been thoroughly studied. This review finds that the effect is relatively robust in basic research, but considerably weaker in applied settings. Motor learning scholars have urged practitioners to develop instructional strategies based upon the inferences of the contextual interference effect. The smaller effects seem to i...

This paper uses Labor Force Survey data for European countries to estimate national investment in assets, where the asset boundary is extended beyond that software and databases as currently defined System of National Accounts. We find that: (a) 2011–2018, 1.4 percent EU-28 employment was engaged formation (software and) with a mean growth rate 5 per annum; (b) on average 2011–2016, expanding r...

Parker (1) has shown that the results of infectivity measurements with vaccinia virus may be interpreted as a Poisson distribution of single infective particles among aliquots of the virus obtained by dilution. Thus, if it may be assumed that there exists a quanti ty of virus invariably necessary and invariably sufficient to produce a lesion in the skin of the rabbit, the behavior on dilution r...