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The early Paleogene, including the Paleocene and Eocene, is characterized by Warmhouse and Hothouse climate states with superimposed transient warming events known as hyperthermals. While these paleoenvironmental changes are well‐documented in the Pacific and Atlantic Oceans, records of such changes in the Indian Ocean are limited. Here, we present a new data set of bulk chemical composition and stable isotopic ratios from the late Paleocene to middle Eocene sediments on the Exmouth Plateau in the mid‐latitude eastern Indian Ocean. The bulk δ13C and δ18O suggest a warming period called the Early Eocene Climatic Optimum (EECO) and cooling toward the middle Eocene in a long‐term perspective. In the short‐term, we identified at least six hyperthermals (Paleocene–Eocene Thermal Maximum, H2, I1, J, ETM3, and L) in the studied sections. By applying independent component (IC) analyses (ICA) to the bulk chemical composition data, we identified six ICs corresponding to sediment source materials and post‐depositional processes. The ICA result infers an increase in detrital materials or a decrease in carbonate rain flux, and an increased population of higher‐order consumers in the oceanic ecosystem during both long‐term (EECO) and short‐term (hyperthermal) warmings around the Exmouth Plateau. Furthermore, ICs representing diagenetic processes and post‐depositional remobilization of elements showed excursions across the hyperthermal horizons, indicating that changes in the redox state of pore or bottom water are associated with hyperthermals. This study provides critical insights into the paleoceanography of the Indian Ocean, highlighting the response of marine environments to both long‐term and short‐term climatic events during the early Paleogene. Plain Language Summary: This study examined marine sediments from the mid‐latitude eastern Indian Ocean dating back to the early Paleogene period, approximately 57 to 40 million years ago. During this time, Earth's climate was much warmer than today, with several short‐term warming events known as hyperthermals. By analyzing the stable carbon and oxygen isotope ratios and the bulk chemical composition of these sediments, we identified six distinct hyperthermals, including the Paleocene–Eocene Thermal Maximum, which was the severest global warming event among the early Paleogene hyperthermals. By applying a multivariate statistical method called independent component analysis to the bulk chemical composition data set, we extracted geochemical features of sediments, including the contributions of source materials (detrital materials, biogenic materials), and signatures of post‐depositional chemical processes. The analysis indicated that inputs of detrital materials from continents and populations of higher consumers in the ocean, such as fish, increased during both long‐ and short‐term warmings. Additionally, several elements were remobilized within the sediment because of changes in the redox state of pore or bottom water. This research provides valuable insights into the link between past climate events and changes in ocean and sediment chemistry, helping us understand how warm periods shaped marine ecosystems and oceanic environments. Key Points: Here, we report bulk δ13C, δ18O, and chemical compositions of early Paleogene sediments from Hole 762C in the Indian OceanWe updated age model of Hole 762C by multiple Eocene hyperthermal horizons, indicated by the bulk δ13C recordIndependent component analysis on bulk compositions revealed Paleogene climate upheavals affected depositional environments at the site [ABSTRACT FROM AUTHOR]

Background: The novel simplified out-of-hospital cardiac arrest (sOHCA) and simplified cardiac arrest hospital prognosis (sCAHP) scores used for prognostication of hospitalised patients have not been externally validated. Therefore, this study aimed to externally validate the sOHCA and sCAHP scores in a Japanese population.Methods: We retrospectively analysed data from a prospectively maintained Japanese database (January 2012 to March 2013). We identified adult patients who had been resuscitated and hospitalised after intrinsic out-of-hospital cardiac arrest (OHCA) (n=2428, age ≥18 years). We validated the sOHCA and sCAHP scores with reference to the original scores in predicting 1-month unfavourable neurological outcomes (cerebral performance categories 3-5) based on the discrimination and calibration measures of area under the receiver operating characteristic curves (AUCs) and a Hosmer-Lemeshow goodness-of-fit test with a calibration plot, respectively.Results: In total, 1985/2484 (82%) patients had a 1-month unfavourable neurological outcome. The original OHCA, sOHCA, original cardiac arrest hospital prognosis (CAHP) and sCAHP scores were available for 855/2428 (35%), 1359/2428 (56%), 1130/2428 (47%) and 1834/2428 (76%) patients, respectively. The AUCs of simplified scores did not differ significantly from those of the original scores, whereas the AUC of the sCAHP score was significantly higher than that of the sOHCA score (0.88 vs 0.81, p<0.001). The goodness of fit was poor in the sOHCA score (ν=8, χ2=19.1 and Hosmer-Lemeshow test: p=0.014) but not in the sCAHP score (ν=8, χ2=13.5 and Hosmer-Lemeshow test: p=0.10).Conclusion: The performances of the original and simplified OHCA and CAHP scores in predicting neurological outcomes in successfully resuscitated OHCA patients were acceptable. With the highest availability, similar discrimination and good calibration, the sCAHP score has promising potential for clinical implementation, although further validation studies to evaluate its clinical acceptance are necessary. [ABSTRACT FROM AUTHOR]

The conversion of hexahydroxo rhenium cluster complexes [[Re.sub.6][Q.sub.8][(OH).sub.6]].sup.4-] (Q = S, Se) in aqueous solutions in a wide pH range were investigated. Results revealed the cluster units to be connected to each other by an extensive system of very strong hydrogen bonds between terminal ligands.

The dinoflagellate Karenia mikimotoi is a red tide–forming alga that causes serious damage to aquaculture in coastal areas around the world. Its eco-physiological characteristics have been investigated extensively but conditions associated with declines of red tides of K. mikimotoi remain unknown. In the present study, we investigated the effects of light and nutrients on the viability, activity of photosystem II (PSII), and motility of K. mikimotoi. Cells were incubated under low (100 μmol photons m−2 s−1 on a 12:12 light:dark cycle of illumination) or high irradiance (1000 μmol photons m−2 s−1) for 4 h in the middle of the photoperiod, in different media. Under low light, most cells survived for about 1 month in media depleted of nitrogen (N) and phosphorus (P), similar to their survival pattern in complete medium. However, when cells that had been pre-incubated in N-depleted medium for 7 d were incubated under high light in an N-depleted medium, cell density and PSII activity declined within a few days. In P-depleted and complete media, there were no significant differences in cell density and PSII activity between low and high light, at least for 10 d. Furthermore, PSII activity was much more sensitive to photoinhibition in N-depleted than in complete medium. The rhythm of diurnal vertical migration of K. mikimotoi was observed in very low light (10 μmol photons m−2 s−1) in different media. The rhythm became obscure in N- and P-depleted media; in fact, most cells stayed in the surface layer all day in N-depleted medium. Moreover, cells accumulating in surface layers in N- and P-depleted media descended very little, even when irradiated with high light. These observations suggest that N-deficiency might trap cells in the surface layer and increase their susceptibility to photoinhibition of PSII, possibly leading to cell death. The combination of N-deficiency and high light thus appears to be an important factor that determines the decline of red tides of K. mikimotoi. [ABSTRACT FROM AUTHOR]