28 research outputs found

    Climate change facilitated the early colonization of the Azores Archipelago during medieval times

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    Humans have made such dramatic and permanent changes to Earth's landscapes that much of it is now substantially and irreversibly altered from its preanthropogenic state. Remote islands, until recently isolated from humans, offer insights into how these landscapes evolved in response to human-induced perturbations. However, little is known about when and how remote systems were colonized because archaeological data and historical records are scarce and incomplete. Here, we use a multiproxy approach to reconstruct the initial colonization and subsequent environmental impacts on the Azores Archipelago. Our reconstructions provide unambiguous evidence for widespread human disturbance of this archipelago starting between 700 -60/+50 and 850 -60/+60 Common Era (CE), ca. 700 y earlier than historical records suggest the onset of Portuguese settlement of the islands. Settlement proceeded in three phases, during which human pressure on the terrestrial and aquatic ecosystems grew steadily (i.e., through livestock introductions, logging, and fire), resulting in irreversible changes. Our climate models suggest that the initial colonization at the end of the early Middle Ages (500 to 900 CE) occurred in conjunction with anomalous northeasterly winds and warmer Northern Hemisphere temperatures. These climate conditions likelyinhibited exploration from southern Europe and facilitated human settlers from the northeast Atlantic. These results are consistent with recent archaeological and genetic data suggesting that the Norse were most likely the earliest settlers on the islands

    Bioaccumulation and Toxicity of Organic Chemicals in Terrestrial Invertebrates

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    Terrestrial invertebrates are key components in ecosystems, with crucial roles in soil structure, functioning, and ecosystem services. The present chapter covers how terrestrial invertebrates are impacted by organic chemicals, focusing on up-to-date information regarding bioavailability, exposure routes and general concepts on bioaccumulation, toxicity, and existing models. Terrestrial invertebrates are exposed to organic chemicals through different routes, which are dependent on both the organismal traits and nature of exposure, including chemical properties and media characteristics. Bioaccumulation and toxicity data for several groups of organic chemicals are presented and discussed, attempting to cover plant protection products (herbicides, insecticides, fungicides, and molluscicides), veterinary and human pharmaceuticals, polycyclic aromatic compounds, polychlorinated biphenyls, flame retardants, and personal care products. Chemical mixtures are also discussed bearing in mind that chemicals appear simultaneously in the environment. The biomagnification of organic chemicals is considered in light of the consumption of terrestrial invertebrates as novel feed and food sources. This chapter highlights how science has contributed with data from the last 5 years, providing evidence on bioavailability, bioaccumulation, and toxicity derived from exposure to organic chemicals, including insights into the main challenges and shortcomings to extrapolate results to real exposure scenarios

    A case study of an individual participant data meta-analysis of diagnostic accuracy showed that prediction regions represented heterogeneity well

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    The diagnostic accuracy of a screening tool is often characterized by its sensitivity and specificity. An analysis of these measures must consider their intrinsic correlation. In the context of an individual participant data meta-analysis, heterogeneity is one of the main components of the analysis. When using a random-effects meta-analytic model, prediction regions provide deeper insight into the effect of heterogeneity on the variability of estimated accuracy measures across the entire studied population, not just the average. This study aimed to investigate heterogeneity via prediction regions in an individual participant data meta-analysis of the sensitivity and specificity of the Patient Health Questionnaire-9 for screening to detect major depression. From the total number of studies in the pool, four dates were selected containing roughly 25%, 50%, 75% and 100% of the total number of participants. A bivariate random-effects model was fitted to studies up to and including each of these dates to jointly estimate sensitivity and specificity. Two-dimensional prediction regions were plotted in ROC-space. Subgroup analyses were carried out on sex and age, regardless of the date of the study. The dataset comprised 17,436 participants from 58 primary studies of which 2322 (13.3%) presented cases of major depression. Point estimates of sensitivity and specificity did not differ importantly as more studies were added to the model. However, correlation of the measures increased. As expected, standard errors of the logit pooled TPR and FPR consistently decreased as more studies were used, while standard deviations of the random-effects did not decrease monotonically. Subgroup analysis by sex did not reveal important contributions for observed heterogeneity; however, the shape of the prediction regions differed. Subgroup analysis by age did not reveal meaningful contributions to the heterogeneity and the prediction regions were similar in shape. Prediction intervals and regions reveal previously unseen trends in a dataset. In the context of a meta-analysis of diagnostic test accuracy, prediction regions can display the range of accuracy measures in different populations and settings

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    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

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    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

    Diatom responses to precipitation and anthropogenic disturbances in an azorean lake during the last seven centuries

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    Sedimentary lacustrine records provide an important source of knowledge of past environmental changes at regional and local scales. Here we perform a diatom-based paleoenvironmental reconstruction, complemented with geochemical proxies, of the recent history of Lake Azul (37 ̊ 52’ 21” N – 25 ̊ 46’ 26” W), located in the crater caldera of Sete Cidades volcano, São Miguel Island. A 132 cm long sediment core from the offshore and deepest part of the lake was selected, from a total of fourteen cores extracted in 2011, and dated with 21Pb and 137Cs, as well as AMS 14C. Two main litological intervals were described: at the lower part there are hard volcanic rocks interbedding silty lacustrine episodes, whereas the upper part is made up by silty mud lacustrine sediments. Eight terrestrial-nearshore levels with high values of TOC/TN ratio, low values of omega13 C and high abundances of aerophilic diatoms, plus nine volcanic levels, were removed from any further analysis in order to assess changes in in-lake processes. Main environmental gradients driving the composition of the diatom assemblages were explored by a Principal Component Analysis (PCA) on the diatom relative abundance data, and four statistically significant Diatom Assemblage Zones (DAZs) were defined with a cluster analysis (CONISS). The first axis of PCA (PC1), explaining 47.3% of total variance, confronts benthic vs tychoplanktonic and euplanktonic taxa, suggesting a relationship with water depth. The second axis (PC2) explained 23.1% of total variance, showing high positive values for eutrophic taxa of the genus Aulacoseira , and negative values for oligotrophic taxa and diatoms of a broad trophic spectrum. This axis is very likely related to a trophic gradient. DAZ-1 (c. 1280 – 1400 cal yr AD), dominated by benthic taxa, is characterized by positive values of PC1 and PC2, indicating relative shallow lake conditions and a high trophic level, respectively. A transition from a benthic to a facultatively planktonic community (lower PC1 values) occurs in DAZ-2 (c. 1400 – 1800 cal yr AD), suggesting a rise in water level, probably triggered by an increase in precipitation. Negative values of PC2 in this zone and DAZ-3 (c. 1800 – 1960 cal yr AD) might be explained by the dilution of nutrients in a larger water volume. The sharp transition to high positive values of PC2 in DAZ-4 (c. 1960 cal yr AD) coincides with the start in the use of nitrate- and phosphate-rich fertilizers in the surrounding farming area. Long-term changes in diatoms assemblages since the late XIII century in Lake Azul are driven by two factors of natural and anthropogenic origin, respectively; the strong inter-annual variability of the precipitation (largely controlled by the North Atlantic Oscillation, NAO), and the eutrophication of lakes in recent decades.Peer Reviewe

    Formation and evolution of back-barrier perched lakes in rocky coasts: an example of a Holocene system in NW Spain

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    Coastal back-barrier perched lakes are freshwater bodies that are elevated over sea-level and are not directly subjected to the inflow of sea-water. This study provides a detailed reconstruction of the Doniños back-barrier perched lake that developed at the end of a small river valley in the rocky coast of the northwest Iberian Peninsula during the Holocene transgression. Its sequence stratigraphy was reconstructed based on a core transect across the system, the analyses of its lithofacies and microfossil assemblages, and a high-resolution radiocarbon-based chronology. The Doniños perched lake was formed ca. 4.5 ka BP. The setting of the perched lake was favoured by Late Holocene sea-level stabilization and the formation of a barrier and back-barrier basin, which was contemporaneous with the high systems tract period. This basin developed over marine and lagoonal sediments deposited between 10.2 and 8.0 ka BP, during rapidly rising sea-level characteristic of the transgressive systems track period. At 1.1 ka BP, the barrier was breached and the perched lake was partially emptied, causing the erosion of the back-barrier basin sediments and a significant sedimentary hiatus. Both enhanced storminess and human intervention were likely responsible for this event. After 1 ka BP, the barrier reclosed and the present-day lake was reformed, with the water level reaching as high as 5 m amsl. The depositional evolution of the Doniños system serves as a model of coastal back-barrier perched lakes in coastal clastic systems that have developed over gently seaward-dipping rugged substrates at small distances from the shoreline and under conditions of rising sea-level and high sediment supply. A review of estuaries, back-barrier lagoons, pocket beaches and back-barrier perched lakes in the rocky coast of the northwest Spain shows that the elevation of the bedrock is the main factor controlling the origin and evolution of these systems

    Formation and evolution of back-barrier perched lakes in rocky coasts: an example of a Holocene system in NW Spain

    No full text
    Coastal back-barrier perched lakes are freshwater bodies that are elevated over sea-level and are not directly subjected to the inflow of sea-water. This study provides a detailed reconstruction of the Doniños back-barrier perched lake that developed at the end of a small river valley in the rocky coast of the northwest Iberian Peninsula during the Holocene transgression. Its sequence stratigraphy was reconstructed based on a core transect across the system, the analyses of its lithofacies and microfossil assemblages, and a high-resolution radiocarbon-based chronology. The Doniños perched lake was formed ca. 4.5 ka BP. The setting of the perched lake was favoured by Late Holocene sea-level stabilization and the formation of a barrier and back-barrier basin, which was contemporaneous with the high systems tract period. This basin developed over marine and lagoonal sediments deposited between 10.2 and 8.0 ka BP, during rapidly rising sea-level characteristic of the transgressive systems track period. At 1.1 ka BP, the barrier was breached and the perched lake was partially emptied, causing the erosion of the back-barrier basin sediments and a significant sedimentary hiatus. Both enhanced storminess and human intervention were likely responsible for this event. After 1 ka BP, the barrier reclosed and the present-day lake was reformed, with the water level reaching as high as 5 m amsl. The depositional evolution of the Doniños system serves as a model of coastal back-barrier perched lakes in coastal clastic systems that have developed over gently seaward-dipping rugged substrates at small distances from the shoreline and under conditions of rising sea-level and high sediment supply. A review of estuaries, back-barrier lagoons, pocket beaches and back-barrier perched lakes in the rocky coast of the northwest Spain shows that the elevation of the bedrock is the main factor controlling the origin and evolution of these systems
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