SYSTEMATICS AND EVOLUTION IN THE TRIBE SCHIZOPETALAE (BRASSICACEAE): A MOLECULAR, MORPHOLOGICAL, AND ECOLOGICAL ANALYSIS OF THE DIVERSIFICATION OF AN ENDEMIC LINEAGE FROM THE ATACAMA DESERT (CHILE)

As aridity has been identified as an active promoter of diversification in deserts, attempts to test organismal differentiation in the Atacama Desert have resulted particularly challenging. Most limitations are related to the recent origin of the extreme aridity in the Atacama Desert, which have stimulated a rapid process of diversification and obscured evidence of interspecific divergence. Based on its favorable biological attributes and high endemicity, genera from the tribe Schizopetalae (Mathewsia and Schizopetalon) emerge as a practical study group to conduct studies of diversification under rapid and recent diversification. The present dissertation focuses on exploring this issue, 1) solving the phylogenetic relationships in the tribe Schizopetalae, 2) describing patterns of interspecific divergence in a well-defined lineage of Schizopetalon from the Atacama Desert, and 3) searching and testing multiple highly variable nuclear loci for phylogenetic and phylogeographic purposes. The results confirmed the monophyletic status of the tribe Schizopetalae and genus Schizopetalon; nevertheless, genus Mathewsia requires to be redefined because the exclusion of M. nivea. Patterns of interspecific differentiation suggest a process of allopatric divergence promoted by ecological niche differentiation between the Andes and coastal ranges in the Atacama Desert. While this result is consistent with previous hypotheses of divergence by habitat differentiation, elements of hybridization, incomplete lineage sorting, and phenotypic plasticity obscured the identification of species limits and precluded a better inference of lineage isolation. The analysis of available genomic resources demonstrated the suitability of obtaining multiple low copy nuclear loci from already available genomic data in Schizopetalon. However, the use of these markers is yet limited, as the detection of multiple copies implies that further analyses are needed to discard paralogous copies. Overall, this dissertation sets the foundation for more elaborated studies, as more available genomic resources and intricate pattern of divergence can result promising to explore the consequences of local patterns of extreme aridity in the diversification and evolution of species of Schizopetalae

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care