Competition, salinity, and clonal growth in native and introduced irises.

PREMISE OF THE STUDY: Iris pseudacorus spread rapidly into North America after introduction from Europe in the 1800s and now co-occurs with native I. hexagona in freshwater Louisiana wetlands. Native irises support and interact with multiple trophic levels, whereas I. pseudacorus is classified an invasive pest because it grows aggressively, reduces biodiversity, and displaces native vegetation. Salinity levels are increasing in coastal wetlands worldwide. We examined how salt-stress affects competitive interactions between these conspecifics. METHODS: We established a three-way full-factorial common-garden experiment that included species (I. pseudacorus, I. hexagona), competition (no competition, intraspecific competition, and interspecific competition), and salinity (0, 4, 8 parts per thousand NaCl), with six replicates per treatment. KEY RESULTS: After 18 mo, Iris pseudacorus produced much more biomass than the native species did (F1, 92 = 71.5, P < 0.0001). Interspecific competition did not affect the introduced iris, but biomass of the native was strongly reduced (competition × species interaction: F2, 95 = 76.7, P = 0.002). Salinity significantly reduced biomass of both species (F2, 92 = 21.8, P < 0.0001), with no species × salinity interaction (F2, 84 = 1.85, P = 0.16). CONCLUSIONS: Our results demonstrate that salt stress strongly reduced clonal reproduction in native and introduced irises; however, the introduced iris had a competitive advantage over the native, regardless of environmental salinity levels. Based on patterns in clonal reproduction, the introduced iris could potentially threaten native iris populations. We are currently investigating seed production and mortality during competition and stress because both clonal and sexual reproduction must be considered when predicting long-term population dynamics.

Post-sternotomy movement strategies in adults: a scoping review.

AIMS: Post-sternotomy movement strategies for adults should be an evidence-informed approach and support a safe, independent return to daily activity. Recent new movement strategies have emerged. The aim of this scoping review was to identify and summarize the available evidence for post-sternotomy movement strategies in adults. METHODS AND RESULTS: The electronic databases searched included MEDLINE, Embase, Sport Discus, CINAHL, Academic Search Complete, the Cochrane Library, Scopus, and PEDro. The search did not have a date limit. After 2405 duplicates were removed, 2978 records were screened, and 12 were included; an additional 2 studies were identified through reference searching for a total of 14 included studies. A data extraction table was used, and the findings are summarized in a tabular and narrative form. Three post-sternotomy movement strategies were identified in the literature: sternal precautions (SP), modified SP, and Keep Your Move in the Tube (KYMITT™). The authors suggested that the practice of SP was based on expert opinion and not founded in evidence. However, the evidence from the identified articles suggested that new movement strategies are safe and allow patients to choose an increased level of activity that promotes improved functional status and confidence. CONCLUSION: More prospective cohort studies and multi-centred randomized control trials are needed; however, the current evidence suggests that modified SP and KYMITT™ are as safe as SP and can promote a patient-centred approach. REGISTRATION: University of Calgary's Digital Repository PRISM http://hdl.handle.net/1880/115439.

Asymptomatic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in adults is uncommon using rigorous symptom characterization and follow-up in an acute-care adult hospital outbreak.

Asymptomatic coronavirus disease 2019 (COVID-19) has been reported as a significant driver of COVID-19 outbreaks. Our hospital ward outbreak analysis suggests that comprehensive symptoms and signs assessment, in combination with adequate follow-up, allows a more precise determination of COVID-19 symptoms. Asymptomatic infection was quite uncommon among adults in this setting.

Patient and ward related risk factors in a multi-ward nosocomial outbreak of COVID-19: Outbreak investigation and matched case-control study.

BACKGROUND: Risk factors for nosocomial COVID-19 outbreaks continue to evolve. The aim of this study was to investigate a multi-ward nosocomial outbreak of COVID-19 between 1st September and 15th November 2020, occurring in a setting without vaccination for any healthcare workers or patients. METHODS: Outbreak report and retrospective, matched case-control study using incidence density sampling in three cardiac wards in an 1100-bed tertiary teaching hospital in Calgary, Alberta, Canada. Patients were confirmed/probable COVID-19 cases and contemporaneous control patients without COVID-19. COVID-19 outbreak definitions were based on Public Health guidelines. Clinical and environmental specimens were tested by RT-PCR and as applicable quantitative viral cultures and whole genome sequencing were conducted. Controls were inpatients on the cardiac wards during the study period confirmed to be without COVID-19, matched to outbreak cases by time of symptom onset dates, age within ± 15 years and were admitted in hospital for at least 2 days. Demographics, Braden Score, baseline medications, laboratory measures, co-morbidities, and hospitalization characteristics were collected on cases and controls. Univariate and multivariate conditional logistical regression was used to identify independent risk factors for nosocomial COVID-19. RESULTS: The outbreak involved 42 healthcare workers and 39 patients. The strongest independent risk factor for nosocomial COVID-19 (IRR 3.21, 95% CI 1.47-7.02) was exposure in a multi-bedded room. Of 45 strains successfully sequenced, 44 (97.8%) were B.1.128 and differed from the most common circulating community lineages. SARS-CoV-2 positive cultures were detected in 56.7% (34/60) of clinical and environmental specimens. The multidisciplinary outbreak team observed eleven contributing events to transmission during the outbreak. CONCLUSIONS: Transmission routes of SARS-CoV-2 in hospital outbreaks are complex; however multi-bedded rooms play a significant role in the transmission of SARS-CoV-2.