Search

Biological invasions in remote areas that experience low human activity provide unique opportunities to elucidate processes responsible for invasion success. Here we study the most widespread invasive plant species across the isolated islands of the Southern Ocean, the annual bluegrass, Poa annua. To analyze geographic variation in genome size, genetic diversity, and reproductive strategies, we sampled all major sub-Antarctic archipelagos in this region and generated microsatellite data for 470 individual plants representing 31 populations. We also estimated genome sizes for a subset of individuals using flow cytometry. Occasional events of island colonization are expected to result in high genetic structure among islands, overall low genetic diversity, and increased self-fertilization, but we show that this is not the case for Poa annua. Microsatellite data indicated low population genetic structure and lack of isolation-by-distance among the sub-Antarctic archipelagos we sampled, but high population structure within each archipelago. We identified high levels of genetic diversity, low clonality, and low selfing rates in sub-Antarctic P. annua populations (contrary to rates typical of continental populations). In turn, estimates of selfing declined in populations as genetic diversity increased. Additionally, we found that most P. annua individuals are likely tetraploid and that only slight variation exists in genome size across the Southern Ocean. Our findings suggest multiple independent introductions of P. annua into the sub-Antarctic, which promoted the establishment of genetically diverse populations. Despite multiple introductions, the adoption of convergent reproductive strategies (outcrossing) happened independently in each major archipelago. The combination of polyploidy and a mixed reproductive strategy likely benefited P. annua in the Southern Ocean by increasing genetic diversity and its ability to cope with the novel environmental conditions.

The operation of long-distance quantum networks requires photons to be synchronized and must account for length variations of quantum channels. We demonstrate a 200 MHz clock-rate fiber optic-based quantum network using off-the-shelf components combined with custom-made electronics and telecommunication C-band photons. The network is backed by a scalable and fully automated synchronization system with ps-scale timing resolution. Synchronization of the photons is achieved by distributing O-band-wavelength laser pulses between network nodes. Specifically, we distribute photon pairs between three nodes, and measure a reduction of coincidence-to-accidental ratio from 77 to only 42 when the synchronization system is enabled, which permits high-fidelity qubit transmission. Our demonstration sheds light on the role of noise in quantum communication and represents a key step in realizing deployed co-existing classical-quantum networks., Comment: 7 pages, 7 figures

The TreeMap 2016 dataset provides detailed spatial information on forest characteristics including number of live and dead trees, biomass, and carbon across the entire forested extent of the continental United States at 30 × 30m resolution, enabling analyses at finer scales where forest inventory is inadequate. We used a random forests machine learning algorithm to assign the most similar Forest Inventory Analysis (FIA) plot to each pixel of gridded LANDFIRE input data. The TreeMap 2016 methodology includes disturbance as a response variable, resulting in increased accuracy in mapping disturbed areas. Within-class accuracy was over 90% for forest cover, height, vegetation group, and disturbance code when compared to LANDFIRE maps. At least one pixel within the radius of validation plots matched the class of predicted values in 57.5% of cases for forest cover, 80.0% for height, 80.0% for tree species with highest basal area, and 87.4% for disturbance. A new feature of the dataset is that it includes linkages to select FIA data in an attribute table included with the TreeMap raster, allowing users to map summaries of 21 variables in a GIS. TreeMap estimates compared favorably with those from FIA at the state level for number of live and dead trees and carbon stored in live and dead trees. Study Implications: TreeMap 2016 provides a 30 × 30 m resolution gridded map of the forests of the continental United States. Attributes of each grid cell include a suite of forest characteristics including biomass, carbon, forest type, and number of live and dead trees. Users can readily produce maps and summaries of these characteristics in a GIS. The TreeMap also includes a database containing, for each pixel, a list of trees with the species, diameter, and height of each tree. TreeMap is being used in the private sector for carbon estimation and by land managers in the National Forest system to investigate questions pertaining to fuel treatments and forest productivity as well as Forest Plan revisions.

SummaryBackgroundPulse oximeters are widely used to monitor blood oxygen saturations, although concerns exist that they are less accurate in individuals with pigmented skin.AimsThis study aimed to determine if patients with pigmented skin were more severely unwell at the period of transfer to intensive care units (ICUs) than individuals with White skin.MethodsUsing data from a large teaching hospital, measures of clinical severity at the time of transfer of patients with COVID-19 infection to ICUs were assessed, and how this varied by ethnic group.ResultsData were available on 748 adults. Median pulse oximetry demonstrated similar oxygen saturations at the time of transfer to ICUs (Kruskal–Wallis test, P = 0.51), although median oxygen saturation measurements from arterial blood gases at this time demonstrated lower oxygen saturations in patients classified as Indian/Pakistani ethnicity (91.6%) and Black/Mixed ethnicity (93.0%), compared to those classified as a White ethnicity (94.4%, Kruskal–Wallis test, P = 0.005). There were significant differences in mean respiratory rates in these patients (P ConclusionsThese data are consistent with the hypothesis that differential measurement error for pulse oximeter readings negatively impact on the escalation of clinical care in individuals from other than White ethnic groups. This has implications for healthcare in Africa and South-East Asia and may contribute to differences in health outcomes across ethnic groups globally.

To examine the association/effect of intraoperative cerebral oximetry (CeOx) on major organ morbidity and mortality (MOMM) after adult cardiac surgery.A retrospective, multicenter cohort study.Patients treated at any hospital within the Society of Thoracic Surgeons Adult Cardiac Surgery Database between July 1, 2011, and December 31, 2016, with a 30-day postoperative follow-up.Individuals ≥18 years old undergoing isolated coronary artery bypass graft (CABG) or valve repair or replacement, or any combination of procedures with cardiopulmonary bypass.Intraoperative CeOx.MOMM includes operative mortality, stroke, renal failure, prolonged mechanical ventilation, deep sternal wound infection, or reoperation for any reason within 30 days. Of 1.19 million patients who met inclusion criteria within 1,180 facilities, ∼30% (n = 361,124) received CeOx versus nonrecipients (n = 838,675) with similar baseline patient characteristics. Using a propensity score-based 1:1 greedy matching method, 99.7% of CeOx recipients (n = 360,285) were matched with nonrecipients. The rates of MOMM were lower with versus without CeOx. The absolute risk reduction translated to a number needed to treat of 227 patients (95% CI: 166-363, p0.0001). In sensitivity analyses of prespecified subgroups, the benefit was strongest among patients undergoing aortic valve repair or replacement ± CABG (more than 7 fewer MOMM events per 1,000, p0.0001). However, intensive care unit stay72 hours was higher with CeOx.Intraoperative cerebral oximetry is associated with less major organ morbidity and mortality after adult cardiac surgery. A large-scale clinical trial is warranted, given that desaturation is common and correctable.