Novel Use of a Social-Media-Based Survey to Detect Regional Differences in Management of Monochorionic-Diamniotic Twins.

ObjectiveThis study aims to evaluate the utility of social media to distribute a patient survey on differences in management and outcomes of monochorionic-diamniotic (MCDA) pregnancies.Study designA cross-sectional survey was posted to an English-language MCDA twins patient-centered support group within the social media site, Facebook from April 2, 2018 to June 26, 2018. Subjects were recruited through a technique called "snowballing," whereby individuals shared the survey to assist with recruiting. Patient reported data were analyzed using Chi-square and Kruskal-Wallis's tests to explore characteristics associated with surveillance and outcomes as related to region and provider type.ResultsOver 3 months, the post "reached" 14,288 Facebook users, among which 5,653 (40%) clicked on the post. A total of 2,357 respondents with MCDA pregnancies completed the survey. Total 1,928 (82%) were from the United States (US) and 419 (18%) from other countries. Total 85% of patients had co-management with maternal-fetal medicine (MFM), more in the US compared with the rest of the world (87 vs. 74%, p < 0.01). MFM involvement led to increased adherence to biweekly ultrasounds (91 vs. 65%, p < 0.01), diagnosis of monochorionicity by 12 weeks (74 vs. 69%, p < 0.01) and better education about twin-twin transfusion syndrome (90 vs. 66%, p < 0.01). Pregnancies with MFM involvement had a higher take-home baby rate for both babies (92 vs. 89%, p < 0.01) or for at least one baby (98 vs. 93%, p < 0.01) compared with those without MFM involvement.ConclusionA survey distributed via social media can be effective in evaluating real-life management and outcomes of an uncommon obstetrical diagnosis. This survey elucidates wide international variation in adherence to guidelines, management, and outcomes

Quantum dots with split enhancement gate tunnel barrier control

We introduce a silicon metal-oxide-semiconductor quantum dot architecture based on a single polysilicon gate stack. The elementary structure consists of two enhancement gates separated spatially by a gap, one gate forming a reservoir and the other a quantum dot. We demonstrate, in three devices based on two different versions of this elementary structure, that a wide range of tunnel rates is attainable while maintaining single-electron occupation. A characteristic change in slope of the charge transitions as a function of the reservoir gate voltage, attributed to screening from charges in the reservoir, is observed in all devices, and is expected to play a role in the sizable tuning orthogonality of the split enhancement gate structure. The all-silicon process is expected to minimize strain gradients from electrode thermal mismatch, while the single gate layer should avoid issues related to overlayers (e.g., additional dielectric charge noise) and help improve yield. Finally, reservoir gate control of the tunnel barrier has implications for initialization, manipulation and readout schemes in multi-quantum dot architectures.Comment: v1: 11 pages, 3 extended data tables, 1 extended data figure, v2: 5 pages, 3 figures, 5 pages supplementary material, 3 extended data tables, 2 extended data figures. Reorganization of the paper structure, modification of the title, abstract and introduction and conclusion, no change to the results and main text figure

High-fidelity single-shot readout for a spin qubit via an enhanced latching mechanism

The readout of semiconductor spin qubits based on spin blockade is fast but suffers from a small charge signal. Previous work suggested large benefits from additional charge mapping processes, however uncertainties remain about the underlying mechanisms and achievable fidelity. In this work, we study the single-shot fidelity and limiting mechanisms for two variations of an enhanced latching readout. We achieve average single-shot readout fidelities > 99.3% and > 99.86% for the conventional and enhanced readout respectively, the latter being the highest to date for spin blockade. The signal amplitude is enhanced to a full one-electron signal while preserving the readout speed. Furthermore, layout constraints are relaxed because the charge sensor signal is no longer dependent on being aligned with the conventional (2, 0) - (1, 1) charge dipole. Silicon donor-quantum-dot qubits are used for this study, for which the dipole insensitivity substantially relaxes donor placement requirements. One of the readout variations also benefits from a parametric lifetime enhancement by replacing the spin-relaxation process with a charge-metastable one. This provides opportunities to further increase the fidelity. The relaxation mechanisms in the different regimes are investigated. This work demonstrates a readout that is fast, has one-electron signal and results in higher fidelity. It further predicts that going beyond 99.9% fidelity in a few microseconds of measurement time is within reach.Comment: Supplementary information is included with the pape

Prevalence of lameness and claw lesions during different stages in the reproductive cycle of sows and the impact on reproduction results

Lameness in sows is an emerging disease condition with major effects on animal welfare and economics. Yet the direct impact on reproduction results remains unclear. The present field study investigated the impact of lameness and claw lesions throughout the reproductive cycle on (re)production results of sows. In five farms, a total of 491 group-housed sows were followed up for a period of one reproductive cycle. Sows were assessed for lameness every time they were moved to another area in the farm. Claw lesions were scored at the beginning and at the end of the cycle. Reproduction results included the number of live-born piglets, stillborn piglets, mummified fetuses and crushed piglets, weaning-to-oestrus interval and the presence of sows not showing oestrus post weaning, returning to service and aborting. Sows that left the group were recorded and the reason was noted. A mean prevalence of lameness of 5.9% was found, although it depended on the time in the productive cycle. The highest percentage of lame sows (8.1%) was found when sows were moved from the post-weaning to the gestation stable. No significant associations were found between lameness and reproduction parameters with the exception of the effect on mummified foetuses. Wall cracks, white line lesions, heel lesions and skin lesions did have an effect on farrowing performance. Of all sows, 22% left the group throughout the study, and almost half of these sows were removed from the farm. Lameness was the second most important reason for culling. Sows culled because of lameness were significantly younger compared with sows culled for other reasons (parity: 2.6 +/- 1.3 v. 4.0 +/- 1.8). In conclusion, the present results indicate that lameness mainly affects farm productivity indirectly through its effect on sow longevity whereas claw lesions directly affect some reproductive parameters. The high percentage of lame sows in the insemination stable indicate that risk factor studies should not only focus on the gestation stable, but also on housing conditions in the insemination stable