Many machine learning (ML) models have been developed for application in the ICU, but few models have been subjected to external validation. The performance of these models in new settings therefore ...remains unknown. The objective of this study was to assess the performance of an existing decision support tool based on a ML model predicting readmission or death within 7 days after ICU discharge before, during, and after retraining and recalibration.
A gradient boosted ML model was developed and validated on electronic health record data from 2004 to 2021. We performed an independent validation of this model on electronic health record data from 2011 to 2019 from a different tertiary care center.
Two ICUs in tertiary care centers in The Netherlands.
Adult patients who were admitted to the ICU and stayed for longer than 12 hours.
None.
We assessed discrimination by area under the receiver operating characteristic curve (AUC) and calibration (slope and intercept). We retrained and recalibrated the original model and assessed performance via a temporal validation design. The final retrained model was cross-validated on all data from the new site. Readmission or death within 7 days after ICU discharge occurred in 577 of 10,052 ICU admissions (5.7%) at the new site. External validation revealed moderate discrimination with an AUC of 0.72 (95% CI 0.67-0.76). Retrained models showed improved discrimination with AUC 0.79 (95% CI 0.75-0.82) for the final validation model. Calibration was poor initially and good after recalibration via isotonic regression.
In this era of expanding availability of ML models, external validation and retraining are key steps to consider before applying ML models to new settings. Clinicians and decision-makers should take this into account when considering applying new ML models to their local settings.
The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >1020 eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ∼50 Mpc through interactions ...with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or γ-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.
We present the design and development of the electronic multi-beam radio astronomy concept (EMBRACE), a demonstrator that is part of the European contribution towards the square kilometre array, ...which is currently being designed by the global radio astronomical community. One of the design goals of EMBRACE is to demonstrate the applicability of phased array technology for use in future radio telescopes. The EMBRACE system will ultimately consist of two stations, the largest of which comprises over 20,000 elements and has a physical area of about 160 m 2 . The antenna system, covering the 500-1500 MHz frequency range, is designed as a dual polarized system, however only the signals for one polarization are processed. To obtain a cost effective design, RF analog beam-forming is performed on tile level close to the radiators. The demonstrator is designed to provide two independent beams such that different parts of the sky can be observed simultaneously. First results from part of the array are presented and discussed. The results show that the complete data path is functional. Since the design resembles a large regular contiguous array, all coupling can be taken into account in the embedded element patterns. The array factor therefore suffices to describe the scanning of the array reducing significantly calibration complexity compared to, e.g. sparse, random or more irregular arrays. This is confirmed by the first array factor measurements, that were done using a novel technique that does not require calibration of the array. The first measurements on an astronomical source, the Sun, indicate that the system noise temperature lies between 104 and 118 K, which is reassuringly close to the design target of 100 K.
The radio frequency window of the square kilometre array is planned to cover the wavelength regime from centimeters up to a few meters. For this range to be optimally covered, different antenna ...concepts are considered. At the lowest frequency range, up to a few gigahertz, it is expected that multibeam techniques will be used, increasing the effective field-of-view to a level that allows very efficient detailed and sensitive exploration of the complete sky. Although sparse narrow-band phased arrays are as old as radio astronomy, multioctave sparse and dense arrays now considered for the SKA require new low-noise design, signal processing, and calibration techniques. The successful implementation of these new array techniques has already been introduced for the use of phased array feeds upgrading existing telescopes: enhancing aperture efficiency as well as effective field-of-view. Especially the development of low-cost array antenna design will allow a cost-effective large-scale implementation for the SKA. This paper addresses these new capabilities, emphasizing the R&D work done in Europe and aims to provide insight into the status of enabling technologies and technical research on polarization, calibration, and side-lobe control that will unleash the potential of phased arrays for future growth of radio astronomy synthesis arrays.
•Approximately one in five femoral fragility fracture patients take an anticoagulant medication, primarily DOACs.•Anticoagulated patients differ in several demographic and comorbidity ...characteristics.•Time to surgery was longer for anticoagulated patients and fewer received surgery within 36 h of admission.•Differences in time to surgery were similar between countries however there was some variation between hospitals.•Adjusted 30-day mortality from admission was higher in anticoagulated patients.
Due to their hypocoagulable state on presentation, anticoagulated patients with femoral fragility fractures typically experience delays to surgery. There are no large, multicentre studies previously carried out within the United Kingdom (UK) evaluating the impact of anticoagulant use in this patient population. This study aimed to evaluate the current epidemiology and compare the perioperative management of anticoagulated and non-anticoagulated femoral fragility fracture patients.
Data was prospectively collected through a collaborative, multicentre approach involving hospitals across the United Kingdom. Femoral fragility fracture patients aged ≥60 years and admitted to hospital between 1st May to 31st July 2023 were included. Main outcomes under investigation included time to surgery, receipt of blood transfusion between admission and 48 h following surgery, length of stay, and 30-day mortality. These were assessed using multivariable linear and logistic regression, and Cox proportional hazards models. Only data from hospitals ≥90 % case ascertainment with reference to figures from the National Hip Fracture Database (NHFD) were analysed.
Data on 10,197 patients from 78 hospitals were analysed. 18.5 % of patients were taking anticoagulants. Compared to non-anticoagulated patients, time to surgery was longer by 7.59 h (95 %CI 4.83–10.36; p < 0.001). 42.41 % of anticoagulated patients received surgery within 36 h (OR 0.54, 95 %CI 0.48–0.60, p < 0.001). Differences in time to surgery were similar between countries however there was some variation across units. There were no differences in blood transfusion and length of stay between groups (OR 1.03, 95 %CI 0.88–1.22, p = 0.646 and 0.22 days, 95 %CI -0.45–0.89; p = 0.887 respectively). Mortality within 30 days of admission was higher in anticoagulated patients (HR 1.27, 95 %CI 1.03–1.57, p = 0.026).
Anticoagulated femoral fragility fracture patients comprise a substantial number of patients, and experience relatively longer delays to surgery with less than half receiving surgery within 36 h of admission. This may have resulted in their comparatively higher mortality rate. Inclusion of anticoagulation status in the minimum data set for the NHFD to enable routine auditing of performance, and development of a national guideline on the management of this growing and emerging patient group is likely to help standardise practice in this area and improve outcomes.
•Only around half of hospitals have dedicated protocols for the perioperative management of patients taking warfarin and DOAC medications.•Substantial variation in guidance exists among protocols of ...different hospitals with a lack of consistency in guidance within the Trauma Network.•A large proportion of protocols lacked guidance on several important aspects of management including type of anaesthesia during surgery.•Existence of dedicated hospital protocols did not improve attainment of the defined targets for time to surgery from admission.
Approximately 20 % of femoral fragility fracture patients take anticoagulants, typically warfarin or Direct Oral AntiCoagulant (DOAC). These can impact timing of surgery affecting patient survival. Due to several possible approaches and numerous factors to consider in the preoperative workup of anticoagulated patients, potential for variations in clinical practice exist. Some hospitals employ dedicated anticoagulation management protocols to address this issue, and to improve time to surgery. This study aimed to determine the proportion of hospitals with such protocols, compare protocol guidance between hospitals, and evaluate the effectiveness of protocols in facilitating prompt surgery.
Data was prospectively collected through a collaborative, multicentre approach involving hospitals across the UK. Femoral fragility fracture patients aged ≥60 years and admitted to hospital between 1st May to 31st July 2023 were included. Information from dedicated anticoagulation management protocols were collated on several domains relating to perioperative care including administration of reversal agents and instructions on timing of surgery as well as others. Logistic regression was used to evaluate effects of dedicated protocols on time to surgery.
Dedicated protocols for management of patients taking warfarin and DOACs were present at 41 (52.6 %) and 43 (55.1 %) hospitals respectively. For patients taking warfarin, 39/41 (95.1 %) protocols specified the dose of vitamin k and the most common was 5 milligrams intravenously (n=21). INR threshold values for proceeding to surgery varied between protocols; 1.5 (n=28), 1.8 (n=6), and 2 (n=6). For patients taking DOACs, 35/43 (81.4 %) and 8/43 (18.6 %) protocols advised timing of surgery based on renal function and absolute time from last dose respectively. Analysis of 10,197 patients from 78 hospitals showed fewer patients taking DOACs received surgery within 36 h of admission at hospitals with a dedicated protocol compared to those without (adjusted OR 0.73, 95% CI 0.54–0.99, p=0.040), while there were no differences among patients taking warfarin (adjusted OR 1.64, 95% CI 0.75–3.57, p=0.219).
Around half of hospitals employed a dedicated anticoagulation management protocol for femoral fragility fracture patients, and substantial variation was observed in guidance between protocols. Dedicated protocols currently being used at hospitals were ineffective at improving the defined targets for time to surgery.
While the opportunities of ML and AI in healthcare are promising, the growth of complex data-driven prediction models requires careful quality and applicability assessment before they are applied and ...disseminated in daily practice. This scoping review aimed to identify actionable guidance for those closely involved in AI-based prediction model (AIPM) development, evaluation and implementation including software engineers, data scientists, and healthcare professionals and to identify potential gaps in this guidance. We performed a scoping review of the relevant literature providing guidance or quality criteria regarding the development, evaluation, and implementation of AIPMs using a comprehensive multi-stage screening strategy. PubMed, Web of Science, and the ACM Digital Library were searched, and AI experts were consulted. Topics were extracted from the identified literature and summarized across the six phases at the core of this review: (1) data preparation, (2) AIPM development, (3) AIPM validation, (4) software development, (5) AIPM impact assessment, and (6) AIPM implementation into daily healthcare practice. From 2683 unique hits, 72 relevant guidance documents were identified. Substantial guidance was found for data preparation, AIPM development and AIPM validation (phases 1-3), while later phases clearly have received less attention (software development, impact assessment and implementation) in the scientific literature. The six phases of the AIPM development, evaluation and implementation cycle provide a framework for responsible introduction of AI-based prediction models in healthcare. Additional domain and technology specific research may be necessary and more practical experience with implementing AIPMs is needed to support further guidance.
The construction costs of distributed radio telescopes are to a great extent determined by the deployment costs of the fiber optic data transport network that is needed to transport the received ...information to the data processor(s). As such, the baseline and data rates that are feasible for a specified amount of money are determined by the status of the technology and deployment costs of the communication network. In this paper the present day data transport status is described and, using a costing model, the most attractive data transport technologies are determined, taking the LOFAR telescope (ASTRON, 2005) as an example. In the outlook, the near-term data transport technology developments are described.
The human gastrointestinal tract contains a complex community of microbes, fulfilling important health-promoting functions. However, this vast complexity of species hampers the assignment of ...responsible organisms to these functions. Recently, Akkermansia muciniphila, a new species from the deeply branched phylum Verrucomicrobia, was isolated from the human intestinal tract based on its capacity to efficiently use mucus as a carbon and nitrogen source. This anaerobic resident is associated with the protective mucus lining of the intestines.
In order to uncover the functional potential of A. muciniphila, its genome was sequenced and annotated. It was found to contain numerous candidate mucinase-encoding genes, but lacking genes encoding canonical mucus-binding domains. Numerous phage-associated sequences found throughout the genome indicate that viruses have played an important part in the evolution of this species. Furthermore, we mined 37 GI tract metagenomes for the presence, and genetic diversity of Akkermansia sequences. Out of 37, eleven contained 16S ribosomal RNA gene sequences that are >95% identical to that of A. muciniphila. In addition, these libraries were found to contain large amounts of Akkermansia DNA based on average nucleotide identity scores, which indicated in one subject co-colonization by different Akkermansia phylotypes. An additional 12 libraries also contained Akkermansia sequences, making a total of ∼16 Mbp of new Akkermansia pangenomic DNA. The relative abundance of Akkermansia DNA varied between <0.01% to nearly 4% of the assembled metagenomic reads. Finally, by testing a large collection of full length 16S sequences, we find at least eight different representative species in the genus Akkermansia.
These large repositories allow us to further mine for genetic heterogeneity and species diversity in the genus Akkermansia, providing novel insight towards the functionality of this abundant inhabitant of the human intestinal tract.
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