Regional synthesis of algal community change in the lakes and tarns of the Windermere catchment, Lake District, UK, since the 19th century

The rural Windermere catchment, English Lake District, UK comprises 11 upland and lowland lakes which feed into Windermere, England’s largest lake. Palaeolimnological algal records, alongside long-term climate and catchment land use monitoring data from all basins in the catchment were used to quantify the relative importance of regional and local-scale drivers of algal community change. Like many temperate lakes, Mann-Kendall trends showed increased concentrations of total algal production and cyanobacteria accompanied by declines in C/N ratios across the Windermere catchment over the last few centuries. Regression tree analyses suggest that nutrient enrichment has an overarching effect, with temperature playing a secondary role. Synchrony and breakpoint analyses suggested that local forcings led to catchment-wide asynchrony of algal communities after the 1950s. In the lowlands (<100 m.a.s.l), 20th century wastewater treatment installation explained the greatest changes in the algal communities, overriding agricultural intensification, but at sites without point sources, correlations to variables that indirectly explain sewage expansion such as resident catchment human populations were apparent. In contrast, algal community change in upland lakes was more responsive to atmospheric pollutants which caused acidification in the late 19th and early 20th century, alongside climatic variables notably temperature. Evidence for upland atmospheric nitrogen deposition in the 20th century was suggested by decreasing stable δ15Norg isotope values, concurrent with increased concentrations of Chlorophyll a (from all algae) but no clear response was found in algal compositional changes. Higher algal community change occurred in lakes with longer residence times overlaying sedimentary geologies typically in the lowlands. However, algal community change was also high in lowland lakes with lower residence times that had point sources, suggesting centennial-scale fertilisation had reduced the ability of local lake characteristics to attenuate environmental change. This work demonstrates that lakes within a few kilometres of one another respond uniquely to environmental change depending on physical characteristics and landscape position. Management measures should focus on reducing nutrients from waste water effluent and develop local stewardship programmes to increase environmental awareness in the region

Regional synthesis of algal community change in the lakes and tarns of the Windermere catchment, Lake District, UK, since the 19th century

The rural Windermere catchment, English Lake District, UK comprises 11 upland and lowland lakes which feed into Windermere, England’s largest lake. Palaeolimnological algal records, alongside long-term climate and catchment land use monitoring data from all basins in the catchment were used to quantify the relative importance of regional and local-scale drivers of algal community change. Like many temperate lakes, Mann-Kendall trends showed increased concentrations of total algal production and cyanobacteria accompanied by declines in C/N ratios across the Windermere catchment over the last few centuries. Regression tree analyses suggest that nutrient enrichment has an overarching effect, with temperature playing a secondary role. Synchrony and breakpoint analyses suggested that local forcings led to catchment-wide asynchrony of algal communities after the 1950s. In the lowlands (<100 m.a.s.l), 20th century wastewater treatment installation explained the greatest changes in the algal communities, overriding agricultural intensification, but at sites without point sources, correlations to variables that indirectly explain sewage expansion such as resident catchment human populations were apparent. In contrast, algal community change in upland lakes was more responsive to atmospheric pollutants which caused acidification in the late 19th and early 20th century, alongside climatic variables notably temperature. Evidence for upland atmospheric nitrogen deposition in the 20th century was suggested by decreasing stable δ15Norg isotope values, concurrent with increased concentrations of Chlorophyll a (from all algae) but no clear response was found in algal compositional changes. Higher algal community change occurred in lakes with longer residence times overlaying sedimentary geologies typically in the lowlands. However, algal community change was also high in lowland lakes with lower residence times that had point sources, suggesting centennial-scale fertilisation had reduced the ability of local lake characteristics to attenuate environmental change. This work demonstrates that lakes within a few kilometres of one another respond uniquely to environmental change depending on physical characteristics and landscape position. Management measures should focus on reducing nutrients from waste water effluent and develop local stewardship programmes to increase environmental awareness in the region

Characterizing wing tears in common pipistrelles (Pipistrellus pipistrellus): investigating tear distribution, wing strength, and possible causes

Bats have large, thin wings that are particularly susceptible to tearing. Anatomical specializations, such as fiber reinforcement, strengthen the wing and increase its resistance to puncture, and an extensive vasculature system across the wing also promotes healing. We investigated whether tear positioning is associated with anatomy in common pipistrelles (Pipistrellus pipistrellus). Wing anatomy was described using histological techniques, imaging, and material testing. Tear information, including type, position, time in rehabilitation, and possible causes, was collected from rehabilitators of injured bats across the United Kingdom. Results suggest that the position of the plagiopatagium (the most proximal wing section to the body), rather than its anatomy, influenced the number, location, and orientation of wing tears. While material testing did not identify the plagiopatagium as being significantly weaker than the chiropatagium (the more distal sections of the wing), the plagiopatagium tended to have the most tears. The position of the tears, close to the body and toward the trailing edge, suggests that they are caused by predator attacks, such as from a cat (Felis catus), rather than collisions. Consistent with this, 38% of P. pipistrellus individuals had confirmed wing tears caused by cats, with an additional 38% identified by rehabilitators as due to suspected cat attacks. The plagiopatagium had the lowest number of blood vessels and highest amounts of elastin fibers, suggesting that healing may take longer in this section. Further investigations into the causes of tears, and their effect on flight capabilities, will help to improve bat rehabilitation

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Unpacking and validating the “cell membrane” core concept of physiology by an Australian team

A task force of physiology educators from 25 Australian universities generated an Australia-wide consensus on seven core concepts for physiology curricula. One adopted core concept was “cell membrane,” defined as “Cell membranes determine what substances enter or leave the cell and its organelles. They are essential for cell signaling, transport, and other cellular functions.” This concept was unpacked by a team of 3 Australian physiology educators into 4 themes and 33 subthemes arranged in a hierarchical structure up to 5 levels deep. The four themes related to defining the cell membrane, cell membrane structure, transport across cell membranes, and cell membrane potentials. Subsequently, 22 physiology educators with a broad range of teaching experience reviewed and assessed the 37 themes and subthemes for importance for students to understand and the level of difficulty for students on a 5-point Likert scale. The majority (28) of items evaluated were rated as either Essential or Important. Theme 2: cell membrane structure was rated as less important than the other three themes. Theme 4: membrane potential was rated most difficult, while theme 1: defining cell membranes was rated as the easiest. The importance of cell membranes as a key aspect of biomedical education received strong support from Australian educators. The unpacking of the themes and subthemes within the cell membrane core concept provides guidance in the development of curricula and should facilitate better identification of the more challenging aspects within this core concept and help inform the time and resources required to support student learning.Full Tex

Early historical forest clearance caused major degradation of water quality at Lake Vaeng, Denmark

Although humans have impacted their environment over millennia, details of these impacts, especially on aquatic systems, is still surprisingly scarce despite potential disturbance by early land use. This study examined a high-resolution radiocarbon-dated Holocene record from the Danish Lake Vaeng, using geochemical and biological proxies, and related the observed impacts to other lake records with catchment disturbance. The results indicate a lengthy and varying history of aquatic eutrophication linked to human activity. Modest impacts on the lake coincided with the first signs of landscape disturbance during the Neolithic (c. 4500 cal. yrs BP). Observed impacts intensified in the Late Bronze and Pre-Roman Iron Age. Viking Age/Medieval deforestation and erosional inputs to the lake associated with new ploughing technology (1200 cal. yrs BP), however, led to a major reorganisation of the aquatic ecosystem. Filamentous bloom-forming cyanobacteria, common today in heavily culturally impacted lakes, reached a historical maxima. The lake ecosystem subsequently recovered somewhat but remains eutrophic to date. The erosion record from Lake Vaeng shows a striking similarity with other Danish lake records, especially the notable increase in Medieval Period catchment inputs, which are observed in other European lacustrine records. Numerous European lowland lakes may have shifted into a degraded ecological state millennia ago, but degradation intensified during the onset of the Medieval Period. Hence, assuming preindustrial conditions as relatively pristine reference baselines for more recent cultural eutrophication could be flawed in landscapes intensively used by humans for millennia.Peer reviewe