Timing of seasonal bird migrations is broadly determined by internal biological clocks, which are synchronized by photoperiod, but individuals often refine their migratory timing decisions in ...response to external factors. Using 11 years of satellite telemetry data, we show that Pacific Barrow's Goldeneye (Bucephala islandica) at higher latitudes initiated spring and molt migrations later and fall migration earlier than individuals at lower latitudes. We further show that individuals refined migratory timing in response to interannual variation in environmental conditions. Individual Barrow's Goldeneye initiated spring migration earlier in years with warmer springs at their overwintering locations and concluded spring migration earlier in years with earlier annual snowmelt on their breeding grounds. Because individuals respond to conditions both where they initiate and where they conclude spring migration, our results suggest that Barrow's Goldeneye update their migratory decisions en route. For all 3 migrations in their annual cycle, birds delayed initiating migration if they had been captured and tagged prior to that migration. Birds that initiated migration late for their latitude were less likely to include a stopover and completed that migration faster, partially compensating for delayed departures. Our results are consistent with the hypothesis that Barrow's Goldeneye uses a combination of endogenous cues and environmental cues in migratory decision making. Sensitivity to environmental cues suggests that Barrow's Goldeneye may have behavioral plasticity that is adaptive when faced with ongoing climate change. Migratory birds time their annual migrations to take advantage of temporal and spatial variation in resources, disease, and predation. Timing of these migrations is broadly determined by an internal biological clock set by day length, but individuals may refine when and how they migrate in response to environmental conditions. We used 11 years of satellite tracking data to investigate migratory cues in Barrow's Goldeneye, a species of sea duck. We found that birds used weather conditions as migratory cues, leaving their wintering grounds earlier in warmer springs and arriving on their breeding grounds earlier when the snow melted earlier in the year. Because individuals respond to conditions both where they start and where they end spring migration, our results suggest that Barrow's Goldeneye update their migratory decisions during migration. Barrow's Goldeneye's ability to respond to environmental cues suggests that they may be able to adapt to ongoing climate change. Le calendrier des migrations saisonnières des oiseaux est largement déterminé par les horloges biologiques internes, qui sont synchronisées par la photopériode, mais les individus affinent souvent leurs décisions en matière de calendrier migratoire en réponse à des facteurs externes. En utilisant 11 années de données de télémétrie par satellite, nous montrons que les individus de Bucephala islandica de la population de l'Ouest ont commencé les migrations printanières et de mue plus tard et la migration automnale plus tôt aux latitudes plus élevées que les individus se trouvant aux latitudes plus basses. Nous montrons également que les individus ont affiné leur calendrier migratoire en réponse aux variations interannuelles des conditions environnementales. Les individus ont commencé leur migration printanière plus tôt les années où les printemps étaient plus chauds dans leurs lieux d'hivernage et ont terminé leur migration printanière plus tôt les années où la fonte annuelle des neiges était plus précoce sur leurs sites de reproduction. Puisque les individus réagissent aux conditions à la fois là où ils commencent et là où ils terminent leur migration printanière, nos résultats suggèrent que l'espèce adapte ses décisions migratoires en cours de route. Pour les trois migrations de leur cycle annuel, les oiseaux ont retardé le début de la migration lorsqu'ils ont été capturés et marqués avant cette migration. Les oiseaux ayant commencé leur migration tardivement pour leur latitude étaient moins susceptibles d'inclure une escale et terminaient cette migration plus rapidement, compensant partiellement les départs retardés. Nos résultats sont cohérents avec l'hypothèse selon laquelle B. islandica utilise une combinaison d'indices endogènes et environnementaux dans la prise de décision migratoire. La sensibilité aux indices environnementaux suggère que cette espèce peut avoir une plasticité comportementale qui s'adapte aux changements climatiques en cours.
COVID pneumonitis can cause patients to become critically ill. They may require intensive care and mechanical ventilation. Ventilator-associated pneumonia (VAP) is a concern. This review discusses ...VAP in this group. Several reasons have been proposed to explain the elevated rates of VAP in critically ill COVID patients compared to non-COVID patients. Extrinsic factors include understaffing, lack of personal protective equipment and use of immunomodulating agents. Intrinsic factors include severe parenchymal damage and immune dysregulation, along with pulmonary vascular endothelial inflammation and thrombosis. The rate of VAP has been reported at 45.4%, with an intensive care unit mortality rate of 42.7%. Multiple challenges to diagnosis exist. Other conditions such as acute respiratory distress syndrome, pulmonary oedema and atelectasis can present with similar features. Frequent growth of gram-negative bacteria has been shown in multiple studies, with particularly high rates of
Pseudomonas aeruginosa
. The rate of invasive pulmonary aspergillosis has been reported at 4–30%. We would recommend the use of invasive techniques when possible. This will enable de-escalation of antibiotics as soon as possible, decreasing overuse. It is also important to keep other possible causes of VAP in mind,
e.g.
COVID-19-associated pulmonary aspergillosis or cytomegalovirus. Diagnostic tests such as galactomannan and β-D-glucan should be considered. These patients may face a long treatment course, with risk of re-infection, along with prolonged weaning, which carries its own long-term consequences.
Genetic variation in Arctic species is often influenced by vicariance during the Pleistocene, as ice sheets fragmented the landscape and displaced populations to low‐ and high‐latitude refugia. The ...formation of secondary contact or suture zones during periods of ice sheet retraction has important consequences on genetic diversity by facilitating genetic connectivity between formerly isolated populations. Brant geese (Branta bernicla) are a maritime migratory waterfowl (Anseriformes) species that almost exclusively uses coastal habitats. Within North America, brant geese are characterized by two phenotypically distinct subspecies that utilize disjunct breeding and wintering areas in the northern Pacific and Atlantic. In the Western High Arctic of Canada, brant geese consist of individuals with an intermediate phenotype that are rarely observed nesting outside this region. We examined the genetic structure of brant geese populations from each subspecies and areas consisting of intermediate phenotypes using mitochondrial DNA (mtDNA) control region sequence data and microsatellite loci. We found a strong east–west partition in both marker types consistent with refugial populations. Within subspecies, structure was also observed at mtDNA while microsatellite data suggested the presence of only two distinct genetic clusters. The Western High Arctic (WHA) appears to be a secondary contact zone for both Atlantic and Pacific lineages as mtDNA and nuclear genotypes were assigned to both subspecies, and admixed individuals were observed in this region. The mtDNA sequence data outside WHA suggests no or very restricted intermixing between Atlantic and Pacific wintering populations which is consistent with published banding and telemetry data. Our study indicates that, although brant geese in the WHA are not a genetically distinct lineage, this region may act as a reservoir of genetic diversity and may be an area of high conservation value given the potential of low reproductive output in this species.
Photographs of the three different plumage coloration types of brant within North America: Pacific Black (left), Western High Arctic (middle), and Atlantic (right). Photograph credit: Maynard Axelson.
Vertebral canal haematoma (VCH) complicates 1 in 168,000 obstetric epidurals (Ruppen et al., 2006). This risk is increased in women with inherited bleeding disorders (IBD). The impact of a ...contraindication to regional anaesthesia on pain management and obstetric outcome in these women is unknown. The purpose of this study was to determine anaesthetic use and obstetric outcomes in a cohort of women with IBD.
97 women with IBD that delivered 130 babies at the CWIUH from Jan 2011 to Dec 2016 were identified from a maternal medicine database. Multidisciplinary planning of peripartum care was communicated to labour ward staff using a simple checklist. The primary bleeding disorders were: Von Willebrands disease (VWD) Type 1 27 (27.8%); VWD Type 2A 3 (3.8%); Low VWF 3 (3.8%); Bleeding disorder of unknown aetiology (BDUA) 19 (19.6%); deficiency of Factors VII, VIII, IX, X, and XI 13 (13.4%); Carriers of Factor VIII, IX, X, XIII deficiency 17 (17.5%); 5 had combined deficiencies (5.2%) and there was one platelet function defect. 9 had a family history of a bleeding disorder (9.3%). Haemostatic support, analgesia, mode of delivery and maternal and fetal outcomes were compared between pregnancies where regional anaesthesia was permitted and those that were not using the Chi-squared test.
When pregnancies where regional anaesthesia was not recommended (49) were compared with pregnancies where regional anaesthesia was considered safe (81), the women were more likely to see an anaesthetist before labour 46 (94%) vs 46 (61%): p < 0.001; to require prophylactic haemostatic support for delivery 30 (61%) vs 1 (1%): p < 0.001; to use a remifentanil infusion 15 (31%) vs 0: p < 0.001, and have general anaesthesia for Caesarean Section (CS) 10 (20%) vs 1(1%): p < 0.001. Vaginal birth 35 (71%) vs 53(65%): p = 0.4 and CS rates 14 (29%) vs 26 (32%) p = 0.28 were similar. Postpartum haemorrhage (PPH) was more common 11 (24%) vs 9(12%) vs p = 0.07 but not statistically so. There were no cases of neonatal bleeding or VCH.
Contraindication to neuraxial blockade in labouring women with IBD does not influence mode of delivery. This information is reassuring to these women who may be anxious about delivery without regional anaesthesia.
Rivers and estuaries are important conduits and reactors for organic matter (OM). Despite the substantial export of terrestrial OM by rivers, only a small proportion of this material reaches the open ...ocean. One potentially important mechanism contributing to the removal of terrestrial dissolved OM (DOM) is flocculation; a process that transforms DOM into larger size fractions that can settle into sediment pools. Here we investigate the role of flocculation in adjacent boreal coastal systems over three consecutive seasons. Flocculation experiments, which include the artificial salting of freshwater DOM to mid (12 psu) and high salinity (25 psu), and a 1:1 mixture of freshwater DOM with their respective saline endmember, highlight a potentially important source of particulate carbon (PC) in boreal estuaries. Along with a 3.5% ± 1.0% removal of dissolved organic carbon (DOC) and 44% ± 16% dissolved iron (DFe), the potential for flocculation of these constituents significantly increased with increasing salinity from 12 to 25 psu. The particulate matter (PM) produced by salt‐induced flocculation was comparable to in situ PC concentrations (in situ PC = 27.5 μmol L−1 and flocculated PC = 15.0 μmol L−1) and stable carbon isotopic signatures (in situ PM = −28.8‰ and flocculated PM = −28.3‰). DFe:DOC and Sr were the only parameters that could significantly explain the degree of carbon and iron flocculation. This demonstrates the importance of DOC, DFe, and optical properties, and the predictive value of DFe:DOC for understanding DOM susceptibility to flocculation and its relevance and contribution to regional and global carbon budgets.
Plain Language Summary
The salt in seawater is an important factor shaping the transport, transformation, and fate of organic matter (OM) from rivers to the ocean. Salts can cause compounds to stick together and form larger particles in a process called flocculation. These larger particles can sink to the bottom where they can be effectively stored in sediments; however, understanding the factors behind how much and where flocculation may occur is still unresolved. Bridging these knowledge gaps will contribute to improved landscape and regional carbon budgets. We investigated the impact of flocculation in two boreal coastal systems using a series of laboratory experiments across multiple seasons. Our findings highlight the important contribution of flocculation in removing OM from the water column. Flocculation can occur across the entire range of estuarine salinities while the degree to which it contributes to particulate OM at a given salinity is dependent upon dissolved OM quantity, source, and composition. We further show flocculation to be a selective process, whereby the concentration of iron and organic carbon, as well as their ratio, can be a useful tool to predict the degree of flocculation at regional scales.
Key Points
Flocculation affects dissolved and particulate organic matter and iron distribution and characteristics; thus is a requisite for carbon flux estimates
Dissolved organic carbon, dissolved iron, and their molar ratio are useful predictors of the spatial and temporal variations in flocculation
Salt‐induced flocculation can occur in salinities up to 25 psu
Coastal ecosystems respond to sea level and sediment supply change according to complex, three‐way interactions between vegetation, hydrology, and sediment transport. While biogeomorphic feedbacks ...preserve the morphology of intertidal surfaces covered by marshland, we demonstrate with numerical model and field experimentation that temporary disturbance to vegetation facilitates rapid and widespread degradation. Vertical accretion slows in disturbed areas, allowing localized submergence of the marsh platform, tidal prism enlargement, and permanent channel network expansion. Vegetated portions of an episodically disturbed platform accrete more rapidly than rates of relative sea level rise, giving submerging marshland the appearance of maintaining elevation. This feedback between vegetation disturbance and channel erosion, and its effect on platform accretion, may explain peculiar patterns of wetland loss in Europe and North America.
Due to multiple risk factors, the rate of ventilator-associated pneumonia in critically ill COVID-19 patients has been reported in a range of 7.6% to 86%. The rate of invasive pulmonary aspergillosis ...in this cohort has been reported at 4% to 30%. We undertook a retrospective chart review of 276 patients who were admitted to intensive care in a large university hospital. The period studied included patients from 23 February 2014 to 12 May 2021. Four groups were collected: COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia. Clinical characteristics, outcomes, and microbiological cultures were recorded. The incidence of ventilator-associated pneumonia in COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia was 5.45%, 27.40%, 16.67%, and 3.41%, respectively (p < 0.001). The rate of invasive pulmonary aspergillosis was 0%, 9.59%, 13.33%, and 6.82%, respectively (p < 0.001). A significantly elevated rate of ventilator-associated pneumonia and invasive pulmonary aspergillosis was noted in the second wave of COVID-19 when compared to the first. This was accompanied by an increase in the mortality rate. Increased steroid use was an independent risk factor for ventilator-associated pneumonia and invasive pulmonary aspergillosis across all four groups. Despite an increased understanding of this disease, no clinical trials have shown any promising therapeutic options at present.
Delineation of population structure provides valuable information for conservation and management of species, as levels of demographic and genetic connectivity not only affect population dynamics but ...also have important implications for adaptability and resiliency of populations and species. Here, we measure population genetic structure and connectivity across the ranges of two sister species of sea ducks: Barrow's goldeneye Bucephala islandica and common goldeneye B. clangula. We use two different marker types: 7–8 nuclear microsatellite loci assayed across 229 samples and 3678 double digest restriction‐site associated DNA sequencing (ddRAD‐seq) loci assayed across 61 samples. First, both datasets found no evidence of genetic structure within common or Barrow's goldeneye, including between North American and European samples of common goldeneye. These results are in contrast with previous mitochondrial DNA, band recovery and telemetry data which suggest that goldeneyes are structured across their range. We posit that the discordance between autosomal genetic markers and other data types suggests that males, possibly subadult males, may be maintaining genetic connectivity across each species' respective ranges. Next, although mate choice consequences resulting from inter‐specific brood parasitism was hypothesized to cause some level of gene flow between goldeneye species, we only identified a single F1 hybrid with no further evidence of contemporary or historical gene flow. Despite ddRAD‐seq demographic analyses which recovered an optimum evolutionary model of split‐with‐migration (i.e. secondary contact), estimates of gene flow were <<1 migrant per generation in both directions. Together, we conclude that either strong ecological barriers or assortative mating are likely playing a role in preventing further backcrossing. Finally, demographic analyses estimated a relatively deep divergence time between Barrow's goldeneye and common goldeneye of ~1.6 million years before present and suggests that the genomes of both species have been under similar evolutionary constraints.
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