22 research outputs found
Do plant traits influence primary succession patterns for bryophytes and vascular plants? Evidence from a 33‐year chronosequence on bare chalk
•1. During primary succession, the abundance of different species and their associated plant traits change over time. Understanding how plant traits linked to colonising and competitive abilities change through succession is important for determining whether community assembly can be predicted. Examining this across more than one taxon group can reveal if these patterns are generalisable.
•2. Here, we investigated primary succession on bare chalk for a chronosequence spanning 33 years for two different taxa, vascular plants and bryophytes. We examined how abundance changed through succession, and how this related to species' colonising and competitive abilities, using relevant plant traits for each taxa. A zero-inflated beta regression model was used to investigate the effects of traits on both presence/absence and abundance-when-present of vascular plants and bryophytes.
•3. Vascular plants with a larger specific leaf area were more likely to occur later in succession. Vascular plants, which were hemicryptophytes, wind dispersing and had a lower canopy height, were more likely to increase in abundance-when-present during succession.
•4. Bryophytes with a larger spore diameter were more likely to occur later in succession. Shorter bryophytes with a greater frequency of sporophyte production had a higher abundance early in succession, representing their high colonising abilities. Whereas later in succession larger bryophytes, with a mat or weft life form and low sporophyte frequency were more abundant, indicating a shift towards greater competitive abilities.
•5. Synthesis. This study has revealed different patterns for vascular plants and bryophytes regarding colonisation and changes in abundance through succession, and the associated traits linked to colonising and competitive abilities. Although some traits were found to influence abundance through succession for vascular plants, these were often contrary to the expected pattern representing the change from colonising to competitive abilities, whereas for bryophytes, there was more evidence for this shift with successional age. This suggests that general theories on succession-linked plant traits should not be relied upon in isolation for the prediction of community assembly. Context, particularly successional age in relation to the available species pool is also key
Chemodynamics of a simulated disc galaxy: initial mass functions and Type Ia supernova progenitors
We trace the formation and advection of several elements within a cosmological adaptive mesh refinement simulation of an L� galaxy. We use nine realizations of the same initial conditions with different stellar initial mass functions (IMFs), mass limits for Type II and Type Ia supernovae (SNII, SNIa) and stellar lifetimes to constrain these subgrid phenomena. Our code includes self-gravity, hydrodynamics, star formation, radiative cooling and feedback from multiple sources within a cosmological framework. Under our assumptions of nucleosynthesis we find that SNII with progenitor masses of up to 100 M� are required to match low-metallicity gas oxygen abundances. Tardy SNIa are necessary to reproduce the classical chemical evolution ‘knee’ in [O/Fe]–[Fe/H]: more prompt SNIa delayed time distributions do not reproduce this feature. Within our framework of hydrodynamical mixing of metals and galaxy mergers we find that chemical evolution is sensitive to the shape of the IMF and that there exists a degeneracy with the mass range of SNII. We look at the abundance plane and present the properties of different regions of the plot, noting the distinct chemical properties of satellites and a series of nested discs that have greater velocity dispersions are more α-rich and metal poor with age
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
The effect of disturbance on the bryophyte flora of Salisbury Plain, western Europe's largest chalk grassland
The military training area on Salisbury Plain contains the largest area of chalk grassland in western Europe. The grassland swards, though relatively tall, are often rich in flowering plant species. The bryophyte flora of areas disturbed in five different ways (prehistoric earthworks, twentieth century rifle ranges, ant-hills, vehicle tracks and shell-holes) was compared to that of adjacent, relatively undisturbed grassland. There was no significant difference in bryophyte cover between quadrats on disturbed ground and the controls, but the disturbed sites supported more bryophyte species per quadrat. Of the 55 taxa recorded, 38 species were at least three times more frequent in the disturbed than the undisturbed sites, compared to four which were at least three times more frequent in the control sites. The species favouring disturbed conditions included several bryophytes characteristically associated with chalk soils in southern England, including some that fruit freely (e.g. Microbryum curvicollum, Tortula lanceola) and others that fruit very rarely (e.g. Abietinella abietina, Entodon concinnus). These results are discussed in relation to the conservation of bryophytes and other disturbance-tolerant and disturbance-dependent species on Salisbury Plain and in the wider context of the protection of the bryophytes of chalkland habitats
Evaluation of the clinical performance of the cobas 4800 HPV test in patients referred for colposcopy.
The clinical performance of the cobas human papillomavirus (HPV) test for detection of high-grade disease in a colposcopy-referred population was compared with that of Hybrid Capture 2 (HC2). The overall agreement between the tests was 92.3%. Clinical sensitivity and specificity for detection of cervical intraepithelial neoplasia grade 2 or greater (CIN2+) were 90.0% and 55.5% for cobas and 90.5% and 50.2% for HC2, respectively. In conclusion, both tests showed comparable performance for detection of CIN2+