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Mineralogy and Geochemistry of a Bentonite Pellets Column Heated for 10 years
- M. V. Villar, J. Cuevas, A. B. Zabala, A. Ortega, A. M. Melón, A. I. Ruiz, R. J. Iglesias
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- Journal:
- Clays and Clay Minerals / Volume 71 / Issue 2 / April 2023
- Published online by Cambridge University Press:
- 01 January 2024, pp. 166-190
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A common design of a high-level radioactive waste (HLW) disposal system consists of the waste canisters emplaced in tunnels or shafts, with the space between the heat-emitting canisters and the surrounding rock filled with a bentonite-based material. Understanding the behavior of this barrier, in particular the effect of prolonged heating on its properties, is important to assess the barrier’s long-term performance. The objective of the present study was to add to this understanding and to supply experimental data about the state of bentonite hydrated and heated for a long period of time. To that end, a 50 cm long column of Wyoming-type bentonite pellets was heated at its base at 140 °C (simulating the waste canister) while a synthetic sodium-chloride-rich groundwater including sulfate, calcium, and magnesium was supplied through its upper surface for almost 10 y. At the end of the experiment the upper half of the column was saturated, but in the lower half the water content decreased sharply toward the heater, where it was close to 0%. No relevant mineralogical changes occurred, and the main component of the bentonite continued to be a predominantly sodium montmorillonite with no structural changes with respect to the initial one. In the area where the temperatures were >60°C and the material very dry, however, the smectite was not able to completely develop the 1-layer hydrate after 48 h of stabilization at RH 55%, although its expandability was fully recovered when the smectite was hydrated with liquid water. The ions solubilized as a result of the water-content increase were transported toward the heater and concentrated in two distinct areas: sodium and calcium chlorides closer to the heater than calcium and sodium sulfates. At the heater contact, the bentonite microstructure was of dense packets with carbon and Na-S-coated cavities. Precipitation of calcite and calcium sulfates and possibly dissolution of silica minerals also took place close to the heater.
Management of routine postoperative pain for children undergoing cardiac surgery: a Paediatric Acute Care Cardiology Collaborative Clinical Practice Guideline
- Dana B. Gal, Caitlin O. Clyde, Erin L. Colvin, Jessica Colyer, Anne M. Ferris, Mayte I. Figueroa, Brittney K. Hills, Sarah M. Lagergren, Jordan Mangum, Jessica L. Mann, Angela S. McKeta, Sonali S. Patel, Jennifer F. Reeves, Molly Richter, Lisa M. Ring, Joshua M. Rosenblum, Kaitlin Tindel, Jeffrey G. Weiner, Kimberly G. Williams, Luis M. Zabala, Nicolas L. Madsen
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- Journal:
- Cardiology in the Young / Volume 32 / Issue 12 / December 2022
- Published online by Cambridge University Press:
- 16 November 2022, pp. 1881-1893
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Background:
Pain following surgery for cardiac disease is ubiquitous, and optimal management is important. Despite this, there is large practice variation. To address this, the Paediatric Acute Care Cardiology Collaborative undertook the effort to create this clinical practice guideline.
Methods:A panel of experts consisting of paediatric cardiologists, advanced practice practitioners, pharmacists, a paediatric cardiothoracic surgeon, and a paediatric cardiac anaesthesiologist was convened. The literature was searched for relevant articles and Collaborative sites submitted centre-specific protocols for postoperative pain management. Using the modified Delphi technique, recommendations were generated and put through iterative Delphi rounds to achieve consensus
Results:60 recommendations achieved consensus and are included in this guideline. They address guideline use, pain assessment, general considerations, preoperative considerations, intraoperative considerations, regional anaesthesia, opioids, opioid-sparing, non-opioid medications, non-pharmaceutical pain management, and discharge considerations.
Conclusions:Postoperative pain among children following cardiac surgery is currently an area of significant practice variability despite a large body of literature and the presence of centre-specific protocols. Central to the recommendations included in this guideline is the concept that ideal pain management begins with preoperative counselling and continues through to patient discharge. Overall, the quality of evidence supporting recommendations is low. There is ongoing need for research in this area, particularly in paediatric populations.
Influence of social cognition as a mediator between cognitive reserve and psychosocial functioning in patients with first episode psychosis
- I González-Ortega, A González-Pinto, S Alberich, E Echeburúa, M Bernardo, B Cabrera, S Amoretti, A Lobo, C Arango, I Corripio, E Vieta, E de la Serna, R Rodriguez-Jimenez, R Segarra, JM López-Ilundain, AM Sánchez-Torres, MJ Cuesta, PEPs Group:, I Zorrilla, P López, M Bioque, G Mezquida, F Barcones, C De-la-Cámara, M Parellada, A Espliego, A Alonso-Solís, EM Grasa, C Varo, L Montejo, J Castro-Fornieles, I Baeza, M Dompablo, I Torio, A Zabala, JI Eguiluz, L Moreno-Izco, J Sanjuan, R Guirado, I Cáceres, P Garnier, F Contreras, J Bobes, S Al-Halabí, J Usall, A Butjosa, S Sarró, R Landin-Romero, A Ibáñez, G Selva
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- Journal:
- Psychological Medicine / Volume 50 / Issue 16 / December 2020
- Published online by Cambridge University Press:
- 22 October 2019, pp. 2702-2710
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Background
Social cognition has been associated with functional outcome in patients with first episode psychosis (FEP). Social cognition has also been associated with neurocognition and cognitive reserve. Although cognitive reserve, neurocognitive functioning, social cognition, and functional outcome are related, the direction of their associations is not clear. Therefore, the main aim of this study was to analyze the influence of social cognition as a mediator between cognitive reserve and cognitive domains on functioning in FEP both at baseline and at 2 years.
MethodsThe sample of the study was composed of 282 FEP patients followed up for 2 years. To analyze whether social cognition mediates the influence of cognitive reserve and cognitive domains on functioning, a path analysis was performed. The statistical significance of any mediation effects was evaluated by bootstrap analysis.
ResultsAt baseline, as neither cognitive reserve nor the cognitive domains studied were related to functioning, the conditions for mediation were not satisfied. Nevertheless, at 2 years of follow-up, social cognition acted as a mediator between cognitive reserve and functioning. Likewise, social cognition was a mediator between verbal memory and functional outcome. The results of the bootstrap analysis confirmed these significant mediations (95% bootstrapped CI (−10.215 to −0.337) and (−4.731 to −0.605) respectively).
ConclusionsCognitive reserve and neurocognition are related to functioning, and social cognition mediates in this relationship.
Trophic cascades in benthic marine ecosystems: lessons for fisheries and protected-area management
- J.K. PINNEGAR, N.V.C. POLUNIN, P. FRANCOUR, F. BADALAMENTI, R. CHEMELLO, M.-L. HARMELIN-VIVIEN, B. HEREU, M. MILAZZO, M. ZABALA, G. D'ANNA, C. PIPITONE
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- Journal:
- Environmental Conservation / Volume 27 / Issue 2 / June 2000
- Published online by Cambridge University Press:
- 10 May 2002, pp. 179-200
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An important principle of environmental science is that changes in single components of systems are likely to have consequences elsewhere in the same systems. In the sea, food web data are one of the few foundations for predicting such indirect effects, whether of fishery exploitation or following recovery in marine protected areas (MPAs). We review the available literature on one type of indirect interaction in benthic marine ecosystems, namely trophic cascades, which involve three or more trophic levels connected by predation. Because many indirect effects have been revealed through fishery exploitation, in some cases we include humans as trophic levels. Our purpose is to establish how widespread cascades might be, and infer how likely they are to affect the properties of communities following the implementation of MPAs or intensive resource exploitation. We review 39 documented cascades (eight of which include humans as a trophic level) from 21 locations around the world; all but two of the cascades are from shallow systems underlain by hard substrata (kelp forests, rocky subtidal, coral reefs and rocky intertidal). We argue that these systems are well represented because they are accessible and also amenable to the type of work that is necessary. Nineteen examples come from the central-eastern and north-eastern Pacific, while no well-substantiated benthic cascades have been reported from the NE, CE or SW Atlantic, the Southern Oceans, E Indian Ocean or NW Pacific. The absence of examples from those zones is probably due to lack of study. Sea urchins are very prominent in the subtidal examples, and gastropods, especially limpets, in the intertidal examples; we suggest that this may reflect their predation by fewer specialist predators than is the case with fishes, but also their conspicuousness to investigators. The variation in ecological resolution amongst studies, and in intensity of study amongst systems and regions, indicates that more cascades will likely be identified in due course. Broadening the concept of cascades to include pathogenic interactions would immediately increase the number of examples. The existing evidence is that cascade effects are to be expected when hard-substratum systems are subject to artisanal resource exploitation, but that the particular problems of macroalgal overgrowth on Caribbean reefs and the expansion of coralline barrens in the Mediterranean rocky-sublittoral will not be readily reversed in MPAs, probably because factors other than predation-based cascades have contributed to them in the first place. More cascade effects are likely to be found in the soft-substratum systems that are crucial to so many large-scale fisheries, when opportunities such as those of MPAs and fishing gradients become available for study of such systems, and the search is widened to less conspicuous focal organisms such as polychaetes and crustaceans.