Improved Neutron Lifetime Measurement with UCNτ.

We report an improved measurement of the free neutron lifetime τ_{n} using the UCNτ apparatus at the Los Alamos Neutron Science Center. We count a total of approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns in 2017 and 2018. We extract τ_{n} from three blinded, independent analyses by both pairing long and short storage time runs to find a set of replicate τ_{n} measurements and by performing a global likelihood fit to all data while self-consistently incorporating the ß-decay lifetime. Both techniques achieve consistent results and find a value τ_{n}=877.75±0.28_{stat}+0.22/-0.16_{syst} s. With this sensitivity, neutron lifetime experiments now directly address the impact of recent refinements in our understanding of the standard model for neutron decay.

Effectiveness of a genetics self-instructional module for nurses involved in egg donor screening.

OBJECTIVE: To evaluate the effectiveness of a self-instructional module in increasing nurses' knowledge of genetics. DESIGN: Pretest/posttest study design. Participants completed a pretest questionnaire used to measure baseline knowledge of basic human genetic concepts and risk assessment and collect descriptive data. Participants then reviewed a self-instructional module and completed a posttest questionnaire. SETTING: Study materials were mailed to 262 registered nurses involved in screening egg donors at 177 reproductive health centers in the United States from July to September 2000. PARTICIPANTS: Sixty-five registered nurses working at reproductive health centers. One hundred of 262 eligible nurses completed the pretest (38% return rate) and 65 of these 100 nurses also completed the posttest (65% retention rate). INTERVENTION: A 22-page self-instructional booklet on genetic risk assessment. MAIN OUTCOME MEASURES: Pretest and posttest responses. RESULTS: There was a significant increase of 20.8% in participants' mean knowledge score on the posttest (M = 89.0%, SD = 8%, range = 67%-100%) as compared with the pretest (M = 69.0%, SD = 12%, range = 42%-92%), based on paired t-test analysis (t = 11.74, SE = 0.426, p < .0001). CONCLUSION: A genetics self-instructional module for registered nurses was effective in increasing knowledge of basic human genetic concepts and risk assessment. More in-depth independent study programs in genetics for nurses are recommended.