The Liuqu Formation in southern Tibet, China, archives the late Palaeocene Liuqu flora (ca. 56 Ma) and represents ancient vegetation on the northern margin of the Indian Plate near the India-Asia collision zone. It therefore provides critical evidence for evaluating early biotic interactions between India and Eurasia. Here, we report on Syzygium (Myrtaceae) fossil leaves from the Liuqu flora. Detailed morphological comparisons suggest that these specimens represent a new fossil species, namely Syzygium ovatum Y. Gao et T. Su sp. nov. By integrating fossil records with deep-time ecological niche modelling, we infer that Syzygium originated on the Indian Plate before or during the Palaeocene. By the middle Eocene, Syzygium had migrated to the northeast along the Asian Pacific coastline to East Asia, consistent with an "Out-of-India" dispersal scenario. Fossil evidence demonstrates that the genus reached New Zealand and Australia by the Early Miocene, likely through a Southeast Asian dispersal corridor. During the Pliocene, the distribution of Syzygium resembled that of its modern range. Although the African fossil record of Syzygium only dates to the early Pliocene, climatic suitability and favourable paleogeographic conditions suggest an earlier arrival: 1) during the Palaeocene via the Kohistan-Ladakh Island Arc and associated island systems or 2) during the Oligocene, when more suitable areas for Syzygium linked Africa and India. Generally, our results suggest a Palaeocene origin of Syzygium on the Indian Plate instead of an early Eocene Australian origin as previously proposed.
Using an event study of U.S.-listed firms, we examine how media reach conditions the stock market reactions to adverse environmental, social, and governance (ESG) news across firms with different ESG performance and industry affiliations. On average, we find that a one-unit increase in media reach is associated with a decrease of 0.13 percentage points in cumulative abnormal returns, indicating an economically meaningful valuation effect. Further analysis shows that this effect is mainly concentrated among low-ESG firms in controversial industries. For high-ESG firms in these industries, media reach makes stock price declines significantly less severe than for low-ESG firms, indicating a media reach insurance effect. However, unless adverse news receives the highest-reach media coverage, we do not find evidence that high ESG performance provides an overall insurance effect. By identifying media reach as a key moderator, this study refines the ESG insurance hypothesis and clarifies when markets value ESG performance.
We investigate three unresolved questions in CM chondrite research: (1) what was the initial O-isotope composition of their accreted water? (2) How much water was accreted? And (3) Did aqueous alteration proceed under open or closed-system conditions? We approach this problem through numerical modelling of the aqueous alteration process using an O-isotope perspective. Our model simulates dissolution and mixing between dry rock and the fluid reservoir, secondary mineralisation (phyllosilicate and calcite) and, in some scenarios open-system evaporative loss. Previously published O-isotope measurements (CM chondrite bulk rock, and T1 and T2 calcite) and a suitable alteration extent (65-85 vol%) are used as constraints against which viable alteration scenarios must match. We find the most likely conditions for alteration were the accretion of water-ice with an approximately Earth-like composition (plotting on or close to the intersection between the TFL and the PCM) and with a delta O-18 value <30 parts per thousand and likely at similar to 5 parts per thousand, prograde conditions (increasing temperature with time), T1 formation before significant protolith was dissolved, an initial water-to-rock (mass) ratio of similar to 0.6 and moderate open system evaporative water loss. The most surprising result of this study is the isotopically light (relatively O-16-rich) initial water composition. We show that this is consistent with fluid compositions independently determined from several other studies. This implies that outer Solar System water was not ubiquitously O-16-poor, as might have been expected based on the composition of isotopically anomalous cosmic symplectite found in Acfer 094.
The shape of a graph arising from the covariation of variables is a crucial idea in reasoning about functions and graphs. Students' perspectives on graph shape may foreground visual features and consider the shape to be a fixed property of the function (static graphical shape thinking). In contrast, students can perceive the graph as a trace of covarying quantities, through which its shape arises (emergent graphical shape thinking). It is of interest to understand how these perspectives are supported and promoted by teachers in classroom discourse. We present findings from a study of classroom discourse in which we used systemic functional linguistics (SFL) to identify features of how teachers and students described graphs. We identified informal but vivid descriptions of graphs that may have affordances for, and even foreground, emergent graphical shape thinking.
Background The Vaccine Safety Datalink (VSD) detected a statistical signal for ischemic events (ischemic stroke or transient ischemic attack) following bivalent mRNA COVID-19 vaccination through prospective surveillance during 2022–2023. Although multiple studies from other surveillance systems and countries reported no increased risk, important methodological limitations remained. This U.S. study addressed those limitations by evaluating the ischemic stroke risk following bivalent mRNA COVID-19 vaccination, influenza vaccination, and their same-day coadministration using an event-dependent self-controlled case series (SCCS) design. Methods Study outcomes included first-ever ischemic stroke (primary outcome), first-in-1-year ischemic stroke (secondary outcome), and ischemic events (exploratory outcomes), identified using ICD-10-CM codes in inpatient and emergency department settings during September 1, 2022–March 31, 2023, among individuals aged ≥12 years across eight VSD sites. Analyses were conducted separately for Pfizer-BioNTech and Moderna bivalent vaccines, with relative incidences (RI) and 95% confidence intervals (CI) estimated for 1–21-day and 1–42-day risk intervals, using person-time outside these intervals as the control period. Subgroup analyses were performed by age group (12–64, ≥65 years) and history of documented SARS-CoV-2 infection. Results A total of 6510 first-ever ischemic strokes were identified among more than 6.8 million participants. Among recipients of Pfizer-BioNTech bivalent COVID-19 and influenza vaccines, no statistically significant increased risk of first-ever ischemic stroke was observed following bivalent COVID-19 vaccination (RI = 0.94; 95% CI: 0.63–1.41), influenza vaccination (RI = 0.95; 95% CI: 0.82–1.10), or same-day coadministration (RI = 1.15; 95% CI: 0.88–1.49) within 1–21-day risk intervals; findings were similar for 1–42-day intervals. Comparable null results were observed for Moderna vaccine and across all subgroups, secondary, and exploratory outcomes. Conclusion No increased risk of ischemic stroke was found following bivalent mRNA COVID-19 vaccination, influenza vaccination, or their coadministration in this multi-site SCCS study. These findings are consistent with previous studies and underscore the importance of continued vaccine safety monitoring.
