34 research outputs found

    Bioerosion on a Terebratula scillae population from the Lower Pleistocene of Lecce area (Southern Italy)

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    This paper deals with shell bioerosion in a population of Terebratula scillae SEGUENZA from the Lower Pleistocene in Lecce area, Southern Italy. The most important traces belong to shell breakage attributed to predatory activity; borings (Entobia isp., Maeandropolydora isp.); drill holes (Oichnus simplex BROMLEY; Oichnus isp.); and etching scars (Centrichnus eccentricus BROMLEY and MARTINELL; Podichnus centrifugalis BROMLEY and SURLYK).The distribution analysis of the traces of epibiosis on the shells of T. scillae induces us to think that we are dealing with a pedicleanchored form, living with completely raised valves. Besides, both percentage and nature of predation marks (probably due to gastropods or decapod crustaceans) do not depose for a very intense predation pressure

    Bioerosion on a Terebratula scillae population from the Lower Pleistocene of Lecce area (Southern Italy)

    Get PDF
    This paper deals with shell bioerosion in a population of Terebratula scillae SEGUENZA from the Lower Pleistocene in Lecce area, Southern Italy. The most important traces belong to shell breakage attributed to predatory activity; borings (Entobia isp., Maeandropolydora isp.); drill holes (Oichnus simplex BROMLEY; Oichnus isp.); and etching scars (Centrichnus eccentricus BROMLEY and MARTINELL; Podichnus centrifugalis BROMLEY and SURLYK). The distribution analysis of the traces of epibiosis on the shells of T. scillae induces us to think that we are dealing with a pedicle-anchored form, living with completely raised valves. Besides, both percentage and nature of predation marks (probably due to gastropods or decapod crustaceans) do not depose for a very intense predation pressure.El presente artículo trata sobre la bioerosión en las conchas de una población de Terebratula scillae SEGUENZA del Pleistoceno inferior del área de Lecce, Sur de Italia. Las principales trazas pertenecen a roturas de la concha atribuidas a la actividad de depredadores; perforaciones (Entobia isp., Maeandropolydora isp.); agujeros (Oichnus simplex BROMLEY; Oichnus isp.); e impresiones (Centrichnus eccentricus BROMLEY and MARTINELL; Podichnus centrifugalis BROMLEY and SURLYK). El análisis de la distribución de las trazas de epibiosis sobre las conchas de T. scillae induce a pensar que se trata de una forma anclada mediante el pedículo, que vivía con las valvas completamente levantadas. Por otra parte, ni los porcentajes ni la naturaleza de las señales de depredación (probablemente debidas a gasterópodos o a crustáceos decápodos) indican una presión de depredación demasiado intensa

    Palaeoclimatic and palaeoenvironmental evolution of the Lower Pleistocene Arda River succession

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    The Arda River marine succession, cropping out in western Emilia (northern Italy) represents an excellent site to study past ecosystems dynamics in the frame of Early Pleistocene climate change and tectonic activity. This one-day excursion leads the participants to discover the palaeoclimatic and palaeoenvironmental evolution of the Lower Pleistocene Arda River marine section, unraveled through an integrated use of sedimentological, palaeoecological (molluscs and trace fossils) and geochemical tools. Upsection, the succession was deposited in progressively shallower water and colder climate during phases of advance of fan deltas affected by hyperpycnal flows. It culminates at the top with clast supported alluvial conglomerates and freshwater/terrestrial biota indicating a sea level drop and the establishment of a continental environment. It is very rich in fossils: in the marine part molluscs, brachiopods, corals and echinoderms, besides well preserved trace fossils, are abundant; whereas in the continental part a mammal fauna and freshwater/terrestrial molluscs are occasionally found. Sclerochemical analyses undertaken on bivalve shells indicate that seawater temperature seasonality was the main variable of climate change within the study area during the Early Pleistocene. In particular, strong seasonality and low winter palaeotemperatures were assumed to be the main drivers for the widespread establishment of Arctica islandica populations in the palaeo-Adriatic Sea around 1.80 Ma. During the excursion not only fossils are shown, but also interesting biocalcarenitic bodies with a complex geometry cropping out in the town of Castell\u2019Arquato. The excursion is complemented by the visit to the Giuseppe Cortesi geological and palaeontological museum, housing vertebrate and invertebrate fossil collections

    Brachiopod-based oxygen-isotope thermometer: Update and review

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    In the early 1950\u2019s, McCrea and Epstein and co-workers laid the foundation for the oxygen isotope-based thermometers. Many variations of the thermometer have been since formulated based on synthetic and biogenic carbonates. Overall, the use and application of oxygen isotope thermometers must consider and be specific as to the mineralogy, and whether it is synthetic, abiogenic or biogenic carbonate. Here, we propose an updated and refined oxygen-isotope thermometer based on a large database of articulated brachiopods from high to low latitudes, cold to warm and shallow to deep-water regimes. In general, brachiopod-based oxygen isotopes are offset from abiogenic calcite precipitated in thermodynamic equilibrium by about -1 . They maintain this offset and that allows for the determination of robust ambient water temperatures over the full marine spectrum. Thus, the specific brachiopod-based oxygen-isotope thermometer applies, with few exceptions, to most modern articulated brachiopods, and potentially their ancient counterparts, and it is as follows: T\ub0C =17.3750 \u2013 4.2535 (\u3b4c-\u3b4w) + 0.1473 (\u3b4c-\u3b4w)2 (N=578, r2 = 0.980) Furthermore, it is imperative that mineralogy and taxa be considered for their appropriateness in the application of oxygen isotope thermometers on synthetic, abiogenic and biogenic marine carbonates. Articulated brachiopods are ideal recorders of oceanographic parameters due to their sessile nature, widespread distribution, high abundance in the Paleozoic and Mesozoic, high resilience to most environmental stresses (e.g., climate change - global warming, ocean acidification), and the resistance of the calcite shell \u2013 the archive \u2013 to post-depositional diagenetic alteration

    Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

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    PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

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    PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks
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