141 research outputs found

    Treated like dirt: Robust forensic and ecological inferences from soil eDNA after challenging sample storage

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    Abstract Biodiversity of soil is routinely assessed with environmental DNA—most often by massive parallel sequencing of marker genes (eDNA metabarcoding). Soil biodiversity may be investigated in relation to biodiversity research or as a tool in forensic investigations. After sampling, the taxonomic composition of soil biotic communities may change. In order to minimize community changes, it is desirable to reduce biological activity, e.g., by freezing immediately after sampling. However, this may be impossible due to remoteness of study sites or, in forensic cases, where soil has been attached to an item of interest for protracted periods of time. Here, we investigated the effect of storage duration and conditions on the assessment of the soil biota with eDNA metabarcoding. We extracted eDNA from freshly collected soil samples and again from the same samples after storage under contrasting temperature conditions and contrasting exposure (open/closed tubes). We used four different primer sets targeting bacteria, fungi, protists (cercozoans), and general eukaryotes. We quantified differences in richness, evenness, and community composition. Subsequently, we tested whether we could correctly infer habitat type and original sample identity after storage using a large reference dataset. We found stronger community composition differences with extended storage time and with higher storage temperature, and differences between open and closed tubes. However, for samples stored <28 days at a maximum of 20°C, changes were generally insignificant. Classification models successfully assigned most samples to their exact location of origin and correct habitat type even after 480 days storage. Even samples showing larger changes generally retained the original sample as the best match. For most biodiversity and forensic applications, storage of samples for days and even several weeks may thus not be a problem, if storage temperature does not exceed 20°C

    Pediatric Emergencies in Helicopter Emergency Medical Services:A National Population-Based Cohort Study From Denmark

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    Study objective: To examine the diagnostic pattern, level of severity of illness or injuries, and mortality among children for whom a physician-staffed helicopter emergency medical service (HEMS) was dispatched. Methods: Population-based cohort study including patients aged less than 16 years treated by the Danish national HEMS from October 1, 2014, to September 30, 2018. Diagnoses were retrieved from inhospital medical records, and the severity of illness or injuries was assessed by a severity score on scene, administration of advanced out-of-hospital care, need for intensive care in a hospital, and mortality. Results: In total, 651 HEMS missions included pediatric patients aged less than 1 year (9.2%), 1 to 2 years (29.0%), 3 to 7 years (28.3%), and 8 to 15 years (33.5%). A third of the patients had critical emergencies (29.6%), and for 20.1% of the patients, 1 or more out-of-hospital interventions were performed: intubation, mechanical chest compressions, intraosseous vascular access, blood transfusion, chest tube insertion, and/or ultrasound examination. Among the 525 patients with hospital follow-up, the most frequent hospital diagnoses were injuries (32.2%), burns (11.2%), and respiratory diseases (7.8%). Within 24 hours of the mission, 18.1% of patients required intensive care. Twenty-nine patients (5.1%, 95% confidence interval [CI] 3.6 to 7.3) died either on or within 1 day of the mission, and the cumulative 30-day mortality was 35 of 565 (6.2%, 95% CI 4.5 to 8.5) (NÂĽ565 first-time missions). Conclusion: On Danish physician-staffed HEMS missions, 1 in 5 pediatric patients required advanced out-of-hospital care. Among hospitalized patients, nearly one-fifth of the patients required immediate intensive care and 6.2% died within 30 days of the mission.publishedVersio
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