Wide-band switches and true-time delay (TTD) phase shifters have been developed using distributed microelectromechanical system (MEMS) transmission lines for applications in phased-array and communication systems. The design consists of a coplanar waveguide (CPW) transmission line (W = G = 100 m) fabricated on a 500-m quartz substrate with fixed-fixed beam MEMS bridge capacitors placed periodically over the transmission line, thus creating a slow-wave structure. A single analog control voltage applied to the center conductor of the CPW line can vary the phase velocity of the loaded line by pulling down on the MEMS bridges to increase the distributed capacitive loading. The resulting change in the phase velocity yields a TTD phase shift. Alternatively, the control voltage can be increased beyond the pull-down voltage of the MEMS bridges such that the capacitive loading greatly increases and shorts the line to ground. The measured results demonstrate 0-60-GHz TTD phase shifters with 2-dB loss/118 phase shift at 60-GHz (4.5-ps TTD) and 1.8-dB loss/84 phase shift at 40 GHz. Also, switches have been demonstrated with an isolation of better than 40 dB from 21 to 40 and 40 to 60 GHz. In addition, a transmission-line model has been developed, which results in very close agreement with the measured data for both the phase shifters and switches. The pull-down voltage is 10-23 V, depending on the residual stress in the MEMS bridge. To our knowledge, this paper presents the first wide-band TTD MEMS phase shifters and wide-band switches to date.

Most studies reported negative outcomes, suggesting that barriers to caregiving have been established, but not facilitators. The interventions described to support carers are limited and require further testing to confirm their effectiveness.

Intravenous beta2-agonists for acute asthma in the emergency department (Review)

IntroductionJackson and Pettit (1998) -henceforth J/P -have recently put forward a general linguistic argument that expressivism about value cannot be maintained as a doctrine distinct from subjectivism. Expressivism claims:The value content of uttered value sentences V resides in the speaker U's conveying that she is in some attitudinal state D. In uttering V, U does not report that she is in D, but merely expresses that she is. Therefore, that U is in D is not part of the (substantial) truth-conditions of V. Value content is not truth-conditional.However, as J/P point out, if clear-cut linguistic rules associate U's expressing that she is in D with her uttering V -which expressivism affirms -then competent use of V involves U's capacity to recognize when she is in D. So in uttering V, in a sincere utterance, U must believe that she is in D and so cannot avoid expressing her belief that she is in D. Thus clear-cut linguistic rules associate utterance of V with belief that U is in D. However, according to J/P, TC holds: TC: If clear-cut linguistic rules associate U's believing P with U's uttering S, P is a component of S's truth-conditions. So, in uttering V, U will be reporting that she is in D, and that she is will be a component of V's truth-conditions. Expressivism then collapses into

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Background We evaluated measures to protect healthcare workers (HCWs) in Vancouver, Canada, where variants of concern (VOC) went from <1% VOC in February 2021 to >92% in mid-May. Canada has amongst the longest periods between vaccine doses worldwide, despite Vancouver having the highest P.1 variant rate outside Brazil. Methods With surveillance data since the pandemic began, we tracked laboratory-confirmed SARS-CoV-2 infections, positivity rates, and vaccine uptake in all 25,558 HCWs in Vancouver Coastal Health, by occupation and subsector, and compared to the general population. Cox regression modelling adjusted for age and calendar-time calculated vaccine effectiveness (VE) against SARS-CoV-2 in fully vaccinated (≥ 7 days post-second dose), partially vaccinated infection (after 14 days) and unvaccinated HCWs; we also compared with unvaccinated community members of the same age-range. Findings Only 3.3% of our HCWs became infected, mirroring community rates, with peak positivity of 9.1%, compared to 11.8% in the community. As vaccine coverage increased, SARS-CoV-2 infections declined significantly in HCWs, despite a surge with predominantly VOC; unvaccinated HCWs had an infection rate of 1.3/10,000 person-days compared to 0.89 for HCWs post first dose, and 0.30 for fully vaccinated HCWs. VE compared to unvaccinated HCWs was 37.2% (95% CI: 16.6–52.7%) 14 days post-first dose, 79.2% (CI: 64.6–87.8%) 7 days post-second dose; one dose provided significant protection against infection until at least day 42. Compared with community infection rates, VE after one dose was 54.7% (CI: 44.8–62.9%); and 84.8% (CI: 75.2–90.7%) when fully vaccinated. Interpretation Rigorous droplet-contact precautions with N95s for aerosol-generating procedures are effective in preventing occupational infection in HCWs, with one dose of mRNA vaccination further reducing infection risk despite VOC and transmissibility concerns. Delaying second doses to allow more widespread vaccination against severe disease, with strict public health, occupational health and infection control measures, has been effective in protecting the healthcare workforce.

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