Precise half-life measurement of the superallowed β+ emitter 10C
The half-life of '°C has been measured to be 19.310(4) s, a result with 0.02% precision, which is a factor of three improvement over the best previous result. Since 10 C is the lightest superallowed 0 + → 0 + β + emitter, its ft value has the greatest weight in setting an upper limit on the possible presence of scalar currents.
Superallowed 
0+→0+
 nuclear 
β
 decays: 2020 critical survey, with implications for 
Vud
 and CKM unitarity
Superallowed $\ensuremath{\beta}$-decay between nuclear analog states with isospin 1 and spin-parity ${0}^{+}$ offers access to fundamental tests of the properties of the electroweak interaction. With 15 such transitions precisely measured, the data collectively probe the conservation of the weak vector current, set tight limits on the presence of beyond-standard-model scalar currents, and yield the most precise value for the ${V}_{u\phantom{\rule{0}{0ex}}d}$ element of the CKM quark-mixing matrix. ${V}_{u\phantom{\rule{0}{0ex}}d}$ is a critical ingredient required to test the unitarity of that matrix. This work provides an in-depth review of the relevant nuclear physics input and connects these data to the fundamental couplings.
In search of optimum chest radiography techniques.
A nation-wide study of chest radiography in Sweden had previously revealed a large variation in the physical and technical factors involved, in particular the radiation dose. In this study the image quality could not be assessed unambiguously. The aim of the present study was to try to establish a correlation between visual grading of radiographs and physical and technical factors in order to find the optimum chest X-ray system. The physical and technical performance of 24 chest units was evaluated. Radiographs were taken of an anthropomorphic chest phantom supplied with test structures simulating various pathologies. Image quality was assessed by visual grading analysis of the radiographs. The physical and technical parameters of the units rated best were used to exemplify good radiographic practice. The results were in agreement with the recommendations issued by the Commission of the European Communities (CEC). It was also shown that low radiation dose is compatible with high-quality radiographic imaging of the chest.