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We report on the demonstration of Al0.85Ga0.15As0.56Sb0.44 (hereafter, AlGaAsSb) avalanche photodiodes (APDs) with a 1000 nm-thick multiplication layer. Such a thick AlGaAsSb device was grown by a digital alloy technique to avoid phase separation. The current-voltage measurements under dark and illumination conditions were performed to determine gain for the AlGaAsSb APDs. The highest gain was ∼ 42, and the avalanche initiation occurred at 21.6 V. The breakdown voltage was found to be around −53 V. The measured dark current densities of bulk and surface components were 6.0 μA/cm2 and 0.23 μA/cm, respectively. These values are about two orders of magnitude lower than those for previously reported 1550 nm-thick AlAs0.56Sb0.44 APDs [Yi et al., Nat. Photonics 13, 683 (2019)]. Excess noise measurements showed that the AlGaAsSb APD has a low k of 0.01 (the ratio of electron and hole impact ionization coefficients) compared to Si APDs. The k of the 1000-nm AlGaAsSb APD is similar to that of the thick AlAsSb APDs (k ∼ 0.005) and 5–8 times lower than that of 170 nm-thick AlGaAsSb APDs (k ∼ 0.5–0.8). Increasing the thickness of the multiplication layer over 1000 nm can also reduce k further since the difference between electron and hole impact ionization coefficients becomes significant in this material system as the thickness of the multiplication layer increases. Therefore, this thick AlGaAsSb-based APD on an InP substrate shows the potential to be a high-performance multiplier that can be used with available short-wavelength infrared (SWIR) absorption layers for a SWIR APD.

How should the quality of medical evidence be evaluated? Proponents of evidence-based medicine advocate the use evidence hierarchies to rank the quality of evidence on the basis that certain methods produce more reliable evidence. Some criticisms of this approach focus on whether certain methods deserve their place in the hierarchy, while others claim that evidence hierarchies should be abandoned in favour of other evidence assessment techniques. We claim that this debate pays insufficient attention to the real-world contexts in which medical decisions are made. To address this limitation, we explore the value of using evidence hierarchies and other evidence assessment techniques in differing contexts of medical decision making and argue that the way in which the quality of medical evidence should be evaluated depends on context. Focusing the discussion of the evaluation of medical evidence on real-world contexts has implications for the viability of the principle of total evidence.

y The SNAP-2: EPICCS collaborators are listed in Supplementary material. AbstractBackground: Decisions to admit high-risk postoperative patients to critical care may be affected by resource availability. We aimed to quantify adult ICU/high-dependency unit (ICU/HDU) capacity in hospitals from the UK, Australia, and New Zealand (NZ), and to identify and describe additional 'high-acuity' beds capable of managing high-risk patients outside the ICU/HDU environment. Methods: We used a modified Delphi consensus method to design a survey that was disseminated via investigator networks in the UK, Australia, and NZ. Hospital-and ward-level data were collected, including bed numbers, tertiary services offered, presence of an emergency department, ward staffing levels, and the availability of critical care facilities. Results: We received responses from 257 UK (response rate: 97.7%), 35 Australian (response rate: 32.7%), and 17 NZ (response rate: 94.4%) hospitals (total 309). Of these hospitals, 91.6% reported on-site ICU or HDU facilities. UK hospitals