Single Spin Measurement using Single Electron Transistors to Probe Two Electron Systems

We present a method for measuring single spins embedded in a solid by probing two electron systems with a single electron transistor (SET). Restrictions imposed by the Pauli Principle on allowed two electron states mean that the spin state of such systems has a profound impact on the orbital states (positions) of the electrons, a parameter which SET's are extremely well suited to measure. We focus on a particular system capable of being fabricated with current technology: a Te double donor in Si adjacent to a Si/SiO2 interface and lying directly beneath the SET island electrode, and we outline a measurement strategy capable of resolving single electron and nuclear spins in this system. We discuss the limitations of the measurement imposed by spin scattering arising from fluctuations emanating from the SET and from lattice phonons. We conclude that measurement of single spins, a necessary requirement for several proposed quantum computer architectures, is feasible in Si using this strategy.Comment: 22 Pages, 8 Figures; revised version contains updated references and small textual changes. Submitted to Phys. Rev.

Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations.Peer reviewe

Single-versus multi-joint isometric protocols to induce a post-activation potentiation effect on squat jump performance

Purpose. The objective of the study was to analyse the effects of post-activation potentiation induced by single- and multijoint maximal voluntary isometric contractions (MVIC) on squat jump performance. Methods. Overall, 13 resistance-training males volunteered to participate in the study. Isometric knee extension exercise was chosen to represent single-joint MVIC (MVIC_SJ) and isometric squat to represent multi-joint MVIC (MVIC_MJ). Four experimental protocols were implemented in a randomized order on different days as follows: P1: squat jump performed before and 3 minutes after MVIC_MJ; P2: squat jump performed before and 7 minutes after MVIC_MJ; P3: squat jump performed before and 3 minutes after MVIC_SJ; P4: squat jump performed before and 7 minutes after MVIC_SJ. Jump height, mean power output, peak power output, net impulse, and electromyographic activity of lower limbs were analysed in squat jump before and after the interventions. Results. ANOVA showed that peak power output increased in P1 (p = 0.04). No difference was found for electromyographic activity in any of the protocols. Conclusions. We concluded that MVIC_MJ performed 3 minutes before the main task (P1) was more effective than MVIC_SJ in optimizing squat jump performance and that the changes in performance were unrelated to muscle activatio