Exploring the Avyssos-Yali-Strogyli submarine volcanic complex at the eastern edge of the Aegean Volcanic Arc

The volcanic centers of Kos, Yali and Nisyros lie at the eastern edge of the Hellenic Volcanic Arc. Recent swath bathymetric surveys and seismic profiling, conducted by HCMR, led to the discovery of several submarine volcanic centers and massive underwater volcaniclastic deposits. Further research aboard the E/V "Nautilus" was conducted at the area in October 2010. Avyssos crater, located northeast of Strongyli islet, is believed to have been the original location of the massive eruption of Kos ignimbrite 160,000 years ago. Exploration of Avyssos showed that it the seafloor is mostly covered with fine-grained sediment full with traces of bioturbation. Hydrothermal activity was not evident at any point. Yali and Strongyli represent Late Pleistocene to Holocene volcanic islands that have developed between the islands of Kos and Tilos. ROV exploration of the eastern flank of Yali revealed wave-type sediment structures, as well as linear fractures at various depths. Several smaller craters were also discovered on the northwest slopes of Strongyli, aligned with ENE-WSW trending fractures with no signs of hydrothermal activity. Heavy biogenic encrustations cover the volcanic rock outcrops on the flanks of both Yali and Strongyli. Analysis of recovered samples will provide information about their relationship to the geology of the nearby islands. © 2013 Gebrüder Borntraeger Verlagsbuchhandlung

Submarine evidence of a debris avalanche deposit on the eastern slope of Santorini volcano, Greece

Hummocky seafloor features were discovered on the eastern flank of Santorini volcano, Greece. Multibeam bathymetric mapping, airgun seismic profiling, side scan sonar survey, and remotely operated vehicle (ROV) dives have been carried out to characterize the nature of the hummocks. These hummocks appear to be composed of several tens of blocks that are up to several hundredmeters in diameter, and are the surface expression of amuch larger deposit than is observed in the bathymetry. The sidescan and airgun data show that the deposit covers an area of approximately 6 km wide by 20 km long, and is up to 75 mthick.We estimate the total volume of the deposit to be approximately 4.4×109 m3. Sampling of these blocks show they are composed of pyroclastic flowdeposits produced during theMinoan eruption of Santorini (ca. 3600 BP).Wepropose that the deposit is the result of a multi-stage landslide event that was caused by one of the several large earthquakes or volcanic eruptions that have occurred in the vicinity of Santorini since theMinoan eruption. One ormore of these events likely triggered the destabilization of a part of the eastern flank of Santorini,which led to a debris avalanche, depositing blocks and forming a hummocky terrain at the base of the island's slope. Themassmovement later evolved into a turbulent suspension flow that traveled 20 km or more from the presumed initial failure. Given the size of the landslide deposit, it might have a tsunami potentially affecting the islands across the southern Aegean Sea. The understanding of earthquake-landslide dynamics has important implications for hazard assessment in this seismically active, historical, and highly populated region of the world. © 2012 Elsevier B.V

Morphological analysis and related volcanic features of the Kolumbo submarine volcanic chain (NE of Santorini Island, Aegean Volcanic Arc)

Kolumbo submarine volcano is located in a small, elongated, rifted basin northeast of Santorini Island, Greece, and has been the site of recent submarine volcanism in the central Hellenic Volcanic Arc. It is the largest of a chain of nineteen volcanic cones occurring within this small rift zone and its most known eruption in 1650 A.D. had a serious impact on Santorini and the surrounding islands. According to previous studies, a range of ages is suggested for the activity along this volcanic line since many of the smaller volcanic cones seem to have been built above the present seafloor, while others are partly buried by Quaternary sediments. The ROVs Hercules and Argus of O.E.T. (Ocean Exploration Trust) were used to explore the slopes, summits and craters of 17 of the 19 submarine volcanic centres identified on multibeam map of the area with E/V Nautilus (NA007) in August 2010. In this paper we present some of the most interesting submarine morphological features along the Kolumbo Volcanic Chain. © 2013 Gebrüder Borntraeger Verlagsbuchhandlung

The detection of volcanic debris avalanches (VDAs) along the Hellenic volcanic arc, through marine geophysical techniques

Recent marine oceanographic surveys using geophysical techniques have revealed a number of volcanic debris avalanche deposits (VDAs) on the external flanks of Antimilos, Santorini and Nisyros volcanoes in the South Aegean Sea. Swath bathymetry and side-scan sonar surveys led to the recognition of characteristic hummocky topography on all of these deposits. On seismic profiles the VDAs are identified by chaotic facies, with incoherent areas bordered by continuous undisturbed seismic reflectors. High-resolution examination of the morphological characteristics of the VDAs was accomplished by using Remotely Operated Vehicles (ROVs), in order to distinguish them from other clastic deposits. In some cases the VDAs can be traced upslope to horseshoe-shaped collapse depressions and represent the expression of the complex evolution of these volcanic edifices. Recognition of VDAs at these volcanic centers has important implications for geohazard assessments as flank collapses have the potential for triggering of large-scale tsunamis. The relationship between the distribution/emplacement mechanisms of the VDA deposits and the source flank collapses remains an area of ongoing research. © Springer International Publishing Switzerland 2014

Safety and efficacy of non-steroidal anti-inflammatory drugs to reduce ileus after colorectal surgery

Background: Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non-steroidal anti-inflammatory drugs (NSAIDs) for reducing ileus after surgery. Methods: A prospective multicentre cohort study was delivered by an international, student- and trainee-led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre-specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury. Results: A total of 4164 patients were included, with a median age of 68 (i.q.r. 57\u201375) years (54\ub79 per cent men). Some 1153 (27\ub77 per cent) received NSAIDs on postoperative days 1\u20133, of whom 1061 (92\ub70 per cent) received non-selective cyclo-oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4\ub76 versus 4\ub78 days; hazard ratio 1\ub704, 95 per cent c.i. 0\ub796 to 1\ub712; P = 0\ub7360). There were no significant differences in anastomotic leak rate (5\ub74 versus 4\ub76 per cent; P = 0\ub7349) or acute kidney injury (14\ub73 versus 13\ub78 per cent; P = 0\ub7666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35\ub73 versus 56\ub77 per cent; P < 0\ub7001). Conclusion: NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement

Safety of hospital discharge before return of bowel function after elective colorectal surgery

© 2020 BJS Society Ltd Published by John Wiley & Sons LtdBackground: Ileus is common after colorectal surgery and is associated with an increased risk of postoperative complications. Identifying features of normal bowel recovery and the appropriateness for hospital discharge is challenging. This study explored the safety of hospital discharge before the return of bowel function. Methods: A prospective, multicentre cohort study was undertaken across an international collaborative network. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The main outcome of interest was readmission to hospital within 30 days of surgery. The impact of discharge timing according to the return of bowel function was explored using multivariable regression analysis. Other outcomes were postoperative complications within 30 days of surgery, measured using the Clavien–Dindo classification system. Results: A total of 3288 patients were included in the analysis, of whom 301 (9·2 per cent) were discharged before the return of bowel function. The median duration of hospital stay for patients discharged before and after return of bowel function was 5 (i.q.r. 4–7) and 7 (6–8) days respectively (P < 0·001). There were no significant differences in rates of readmission between these groups (6·6 versus 8·0 per cent; P = 0·499), and this remained the case after multivariable adjustment for baseline differences (odds ratio 0·90, 95 per cent c.i. 0·55 to 1·46; P = 0·659). Rates of postoperative complications were also similar in those discharged before versus after return of bowel function (minor: 34·7 versus 39·5 per cent; major 3·3 versus 3·4 per cent; P = 0·110). Conclusion: Discharge before return of bowel function after elective colorectal surgery appears to be safe in appropriately selected patients

Safety of hospital discharge before return of bowel function after elective colorectal surgery

Background: Ileus is common after colorectal surgery and is associated with an increased risk of postoperative complications. Identifying features of normal bowel recovery and the appropriateness for hospital discharge is challenging. This study explored the safety of hospital discharge before the return of bowel function. Methods: A prospective, multicentre cohort study was undertaken across an international collaborative network. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The main outcome of interest was readmission to hospital within 30 days of surgery. The impact of discharge timing according to the return of bowel function was explored using multivariable regression analysis. Other outcomes were postoperative complications within 30 days of surgery, measured using the Clavien\u2013Dindo classification system. Results: A total of 3288 patients were included in the analysis, of whom 301 (9\ub72 per cent) were discharged before the return of bowel function. The median duration of hospital stay for patients discharged before and after return of bowel function was 5 (i.q.r. 4\u20137) and 7 (6\u20138) days respectively (P &lt; 0\ub7001). There were no significant differences in rates of readmission between these groups (6\ub76 versus 8\ub70 per cent; P = 0\ub7499), and this remained the case after multivariable adjustment for baseline differences (odds ratio 0\ub790, 95 per cent c.i. 0\ub755 to 1\ub746; P = 0\ub7659). Rates of postoperative complications were also similar in those discharged before versus after return of bowel function (minor: 34\ub77 versus 39\ub75 per cent; major 3\ub73 versus 3\ub74 per cent; P = 0\ub7110). Conclusion: Discharge before return of bowel function after elective colorectal surgery appears to be safe in appropriately selected patients