Method Of Sampling Seed Banks In Arable Soils With Special Reference To Chenopodium Spp

Since sampling procedures for seed bank studies have long been ignored, my objective was to evolve a procedure which would give an unbiased estimate of the seed bank of a major weed species while minimizing the sampling variance and the sampling effort. 1024 soil cores (1.9 cm in diameter and 15 cm deep) were taken systematically over 1.35 ha in a corn field in Oxford County, Ontario. Intact seeds of Chenopodium spp. were extracted using a solution of sodium hexametaphosphate and sodium bicarbonate (2:1 w/w). Seed numbers were recorded to create a data bank from which repeated samplings with replacement were made to compare random, systematic, stratified random and cluster sampling in their capacity to minimize the sampling variance calculated by the Monte Carlo technique (MC S(,x)(\u272)). MC S(,x)(\u272) values decreased with increasing sample size regardless of the sampling method used. MC S(,x)(\u272) values for systematic and cluster sampling were greatly influenced by the sampling interval and the shape and size of the cluster respectively. This was attributed to the underlying aggregate seed distribution of Chenopodium spp. in the soil with its pattern of high and low seed density parallel to corn rows. There were some differences between MC S(,x)(\u272) values from random and stratified random sampling but either of these methods could be used to sample seed banks. Of the auger sizes tested (1.9, 2.7 and 3.3 cm in diameter and 15 cm deep), the smallest sampling unit gave the most precise estimate of the density of Chenopodium spp. seeds on a per volume basis. The minimum sample size needed to estimate the seed bank size for a common species ranged between 60 and 100 small sampling units. Fields under various crop rotations were found to have similar sized seed banks of Chenopodium spp. (802 to 2912 seeds/m(\u272)). Application of manure increased the number of Chenopodium spp. seeds in the soil (11 829 seeds/m(\u272)) the most. Two fallow fields with large populations of lamb\u27s-quarters had similarly large seed banks (16 357 and 21 512 seeds/m(\u272)). The seed banks of Chenopodium spp. of all fields surveyed averaged 92% black seeds and 8% brown seeds. The contributions of the different categories of Chenopodium spp. seeds to the seed population in the soil were consistent throughout all fields with approximately 10% whole (viable) seeds, 56% damaged seeds and 34% underdeveloped seeds

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Stork’s bill (Erodium cicutarium (L.) L’Her. ex Ait) and hemp-nettle (Galeopsis tetrahit L.): a cautionary note for eastern Canada field crops

Stork’s bill was observed for the first time in 2009, and again in 2010, in a 22-yr-old conservation tillage study at La Pocatière, Québec. Within a year, the species had spread from two to ten plots, with densities ranging between 100 and 232 plants m-2 in 2010 compared with ≤ 12 plants m-2 in 2009. Currently, stork’s bill is not a major agricultural weed in eastern Canada; it should therefore be monitored closely and acted upon rapidly to prevent its establishment and spread. The relatively high hemp-nettle density in no-till compared with tilled treatments in 2009 was attributed to a cultivation operation conducted exceptionally in no-till treatments, confirming the responsiveness of the species to tillage.L’érodium cicutaire a été observée pour la première fois en 2009, puis à nouveau en 2010, dans une étude sur la conservation des sols en place depuis 22 ans, à La Pocatière, Québec. En un an, l’espèce s’est répandue de deux à dix parcelles et la densité est passée de ≤ 12 plants m-2 en 2009 à 100-232 plants m-2 en 2010. L’érodium cicutaire, n’étant pas une mauvaise herbe d’importance agricole dans l’est canadien, devra être surveillée étroitement de façon à pouvoir intervenir rapidement et prévenir son expansion. La densité relativement élevée d’ortie royale dans le semis direct comparativement aux parcelles avec travail du sol en 2009 a été attribuée à une opération exceptionnelle de sarclage mécanique dans le semis direct, ce qui confirme la sensibilité de l’espèce au travail du sol

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome Associated with COVID-19: An Emulated Target Trial Analysis

International audienc

Predicting 90-day survival of patients with COVID-19: Survival of Severely Ill COVID (SOSIC) scores

International audienceBackground Predicting outcomes of critically ill intensive care unit (ICU) patients with coronavirus-19 disease (COVID-19) is a major challenge to avoid futile, and prolonged ICU stays. Methods The objective was to develop predictive survival models for patients with COVID-19 after 1-to-2 weeks in ICU. Based on the COVID–ICU cohort, which prospectively collected characteristics, management, and outcomes of critically ill patients with COVID-19. Machine learning was used to develop dynamic, clinically useful models able to predict 90-day mortality using ICU data collected on day (D) 1, D7 or D14. Results Survival of Severely Ill COVID (SOSIC)-1, SOSIC-7, and SOSIC-14 scores were constructed with 4244, 2877, and 1349 patients, respectively, randomly assigned to development or test datasets. The three models selected 15 ICU-entry variables recorded on D1, D7, or D14. Cardiovascular, renal, and pulmonary functions on prediction D7 or D14 were among the most heavily weighted inputs for both models. For the test dataset, SOSIC-7’s area under the ROC curve was slightly higher (0.80 [0.74–0.86]) than those for SOSIC-1 (0.76 [0.71–0.81]) and SOSIC-14 (0.76 [0.68–0.83]). Similarly, SOSIC-1 and SOSIC-7 had excellent calibration curves, with similar Brier scores for the three models. Conclusion The SOSIC scores showed that entering 15 to 27 baseline and dynamic clinical parameters into an automatable XGBoost algorithm can potentially accurately predict the likely 90-day mortality post-ICU admission (sosic.shinyapps.io/shiny). Although external SOSIC-score validation is still needed, it is an additional tool to strengthen decisions about life-sustaining treatments and informing family members of likely prognosis

Correction to: Characteristics and prognosis of bloodstream infection in patients with COVID‑19 admitted in the ICU: an ancillary study of the COVID‑ICU study

International audienc

Benefits and risks of noninvasive oxygenation strategy in COVID-19: a multicenter, prospective cohort study (COVID-ICU) in 137 hospitals

International audienceAbstract Rational To evaluate the respective impact of standard oxygen, high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) on oxygenation failure rate and mortality in COVID-19 patients admitted to intensive care units (ICUs). Methods Multicenter, prospective cohort study (COVID-ICU) in 137 hospitals in France, Belgium, and Switzerland. Demographic, clinical, respiratory support, oxygenation failure, and survival data were collected. Oxygenation failure was defined as either intubation or death in the ICU without intubation. Variables independently associated with oxygenation failure and Day-90 mortality were assessed using multivariate logistic regression. Results From February 25 to May 4, 2020, 4754 patients were admitted in ICU. Of these, 1491 patients were not intubated on the day of ICU admission and received standard oxygen therapy (51%), HFNC (38%), or NIV (11%) ( P < 0.001). Oxygenation failure occurred in 739 (50%) patients (678 intubation and 61 death). For standard oxygen, HFNC, and NIV, oxygenation failure rate was 49%, 48%, and 60% ( P < 0.001). By multivariate analysis, HFNC (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.36–0.99, P = 0.013) but not NIV (OR 1.57, 95% CI 0.78–3.21) was associated with a reduction in oxygenation failure). Overall 90-day mortality was 21%. By multivariable analysis, HFNC was not associated with a change in mortality (OR 0.90, 95% CI 0.61–1.33), while NIV was associated with increased mortality (OR 2.75, 95% CI 1.79–4.21, P < 0.001). Conclusion In patients with COVID-19, HFNC was associated with a reduction in oxygenation failure without improvement in 90-day mortality, whereas NIV was associated with a higher mortality in these patients. Randomized controlled trials are needed

Characteristics and prognosis of bloodstream infection in patients with COVID-19 admitted in the ICU: an ancillary study of the COVID-ICU study

International audienceBackground Patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-COV 2) and requiring intensive care unit (ICU) have a high incidence of hospital-acquired infections; however, data regarding hospital acquired bloodstream infections (BSI) are scarce. We aimed to investigate risk factors and outcome of BSI in critically ill coronavirus infectious disease-19 (COVID-19) patients. Patients and methods We performed an ancillary analysis of a multicenter prospective international cohort study (COVID-ICU study) that included 4010 COVID-19 ICU patients. For the present analysis, only those with data regarding primary outcome (death within 90 days from admission) or BSI status were included. Risk factors for BSI were analyzed using Fine and Gray competing risk model. Then, for outcome comparison, 537 BSI-patients were matched with 537 controls using propensity score matching. Results Among 4010 included patients, 780 (19.5%) acquired a total of 1066 BSI (10.3 BSI per 1000 patients days at risk) of whom 92% were acquired in the ICU. Higher SAPS II, male gender, longer time from hospital to ICU admission and antiviral drug before admission were independently associated with an increased risk of BSI, and interestingly, this risk decreased over time. BSI was independently associated with a shorter time to death in the overall population (adjusted hazard ratio (aHR) 1.28, 95% CI 1.05–1.56) and, in the propensity score matched data set, patients with BSI had a higher mortality rate (39% vs 33% p = 0.036). BSI accounted for 3.6% of the death of the overall population. Conclusion COVID-19 ICU patients have a high risk of BSI, especially early after ICU admission, risk that increases with severity but not with corticosteroids use. BSI is associated with an increased mortality rate