Holocene tephrochronology of the lower Río Cisnes valley, southern Chile

Sediment cores from lakes and bogs in the Río Cisnes valley contain tephra from explosive eruptions of volcanoes in the southern part of the Andean Southern Volcanic Zone (SSVZ). These tephra, which thicken and coarsen to the west, are attributed to eruptions from Melimoyu, Mentolat, Hudson, and potentially either Macá, Cay or one of the many minor eruptive centers (MEC) located both along the Liquiñe-Ofqui Fault Zone (LOFZ) and surrounding the major volcanoes. Correlation of the tephra between two new cores in the lower Río Cisnes valley, and amongst other cores previously described from the region, and source volcano identification for the tephra, has been done using lithostratigraphic data (tephra layer thickness and grain size), petrography (tephra glass color, vesicle morphology, and type and abundance of phenocryst phases), and by comparison of bulk tephra trace-element characteristics with previously published whole-rock and bulk tephra chemical analysis. Four tephras in these cores are attributed to eruptions of Mentolat, four to eruptions from Melimoyu, one possibly to Hudson, and six cannot be assigned to a specific source volcano. Some of these tephra correspond to pyroclastic tephra fall deposits previously observed in outcrop, including the MEL2 eruption of Melimoyu and the MEN1 eruption of Mentolat. However, others have not been previously observed and represent the products of newly identified small to medium sized eruptions from volcanoes of the SSVZ. These results provide new information concerning the frequency and magnitude of explosive eruption of SSVZ volcanoes and contribute to the evaluation of volcanic hazards in the region

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

State of the climate in 2018

In 2018, the dominant greenhouse gases released into Earth’s atmosphere—carbon dioxide, methane, and nitrous oxide—continued their increase. The annual global average carbon dioxide concentration at Earth’s surface was 407.4 ± 0.1 ppm, the highest in the modern instrumental record and in ice core records dating back 800 000 years. Combined, greenhouse gases and several halogenated gases contribute just over 3 W m−2 to radiative forcing and represent a nearly 43% increase since 1990. Carbon dioxide is responsible for about 65% of this radiative forcing. With a weak La Niña in early 2018 transitioning to a weak El Niño by the year’s end, the global surface (land and ocean) temperature was the fourth highest on record, with only 2015 through 2017 being warmer. Several European countries reported record high annual temperatures. There were also more high, and fewer low, temperature extremes than in nearly all of the 68-year extremes record. Madagascar recorded a record daily temperature of 40.5°C in Morondava in March, while South Korea set its record high of 41.0°C in August in Hongcheon. Nawabshah, Pakistan, recorded its highest temperature of 50.2°C, which may be a new daily world record for April. Globally, the annual lower troposphere temperature was third to seventh highest, depending on the dataset analyzed. The lower stratospheric temperature was approximately fifth lowest. The 2018 Arctic land surface temperature was 1.2°C above the 1981–2010 average, tying for third highest in the 118-year record, following 2016 and 2017. June’s Arctic snow cover extent was almost half of what it was 35 years ago. Across Greenland, however, regional summer temperatures were generally below or near average. Additionally, a satellite survey of 47 glaciers in Greenland indicated a net increase in area for the first time since records began in 1999. Increasing permafrost temperatures were reported at most observation sites in the Arctic, with the overall increase of 0.1°–0.2°C between 2017 and 2018 being comparable to the highest rate of warming ever observed in the region. On 17 March, Arctic sea ice extent marked the second smallest annual maximum in the 38-year record, larger than only 2017. The minimum extent in 2018 was reached on 19 September and again on 23 September, tying 2008 and 2010 for the sixth lowest extent on record. The 23 September date tied 1997 as the latest sea ice minimum date on record. First-year ice now dominates the ice cover, comprising 77% of the March 2018 ice pack compared to 55% during the 1980s. Because thinner, younger ice is more vulnerable to melting out in summer, this shift in sea ice age has contributed to the decreasing trend in minimum ice extent. Regionally, Bering Sea ice extent was at record lows for almost the entire 2017/18 ice season. For the Antarctic continent as a whole, 2018 was warmer than average. On the highest points of the Antarctic Plateau, the automatic weather station Relay (74°S) broke or tied six monthly temperature records throughout the year, with August breaking its record by nearly 8°C. However, cool conditions in the western Bellingshausen Sea and Amundsen Sea sector contributed to a low melt season overall for 2017/18. High SSTs contributed to low summer sea ice extent in the Ross and Weddell Seas in 2018, underpinning the second lowest Antarctic summer minimum sea ice extent on record. Despite conducive conditions for its formation, the ozone hole at its maximum extent in September was near the 2000–18 mean, likely due to an ongoing slow decline in stratospheric chlorine monoxide concentration. Across the oceans, globally averaged SST decreased slightly since the record El Niño year of 2016 but was still far above the climatological mean. On average, SST is increasing at a rate of 0.10° ± 0.01°C decade−1 since 1950. The warming appeared largest in the tropical Indian Ocean and smallest in the North Pacific. The deeper ocean continues to warm year after year. For the seventh consecutive year, global annual mean sea level became the highest in the 26-year record, rising to 81 mm above the 1993 average. As anticipated in a warming climate, the hydrological cycle over the ocean is accelerating: dry regions are becoming drier and wet regions rainier. Closer to the equator, 95 named tropical storms were observed during 2018, well above the 1981–2010 average of 82. Eleven tropical cyclones reached Saffir–Simpson scale Category 5 intensity. North Atlantic Major Hurricane Michael’s landfall intensity of 140 kt was the fourth strongest for any continental U.S. hurricane landfall in the 168-year record. Michael caused more than 30 fatalities and $25 billion (U.S. dollars) in damages. In the western North Pacific, Super Typhoon Mangkhut led to 160 fatalities and$6 billion (U.S. dollars) in damages across the Philippines, Hong Kong, Macau, mainland China, Guam, and the Northern Mariana Islands. Tropical Storm Son-Tinh was responsible for 170 fatalities in Vietnam and Laos. Nearly all the islands of Micronesia experienced at least moderate impacts from various tropical cyclones. Across land, many areas around the globe received copious precipitation, notable at different time scales. Rodrigues and Réunion Island near southern Africa each reported their third wettest year on record. In Hawaii, 1262 mm precipitation at Waipā Gardens (Kauai) on 14–15 April set a new U.S. record for 24-h precipitation. In Brazil, the city of Belo Horizonte received nearly 75 mm of rain in just 20 minutes, nearly half its monthly average. Globally, fire activity during 2018 was the lowest since the start of the record in 1997, with a combined burned area of about 500 million hectares. This reinforced the long-term downward trend in fire emissions driven by changes in land use in frequently burning savannas. However, wildfires burned 3.5 million hectares across the United States, well above the 2000–10 average of 2.7 million hectares. Combined, U.S. wildfire damages for the 2017 and 2018 wildfire seasons exceeded $40 billion (U.S. dollars)

DNA methylation profiling to predict recurrence risk in meningioma: development and validation of a nomogram to optimize clinical management

Abstract Background Variability in standard-of-care classifications precludes accurate predictions of early tumor recurrence for individual patients with meningioma, limiting the appropriate selection of patients who would benefit from adjuvant radiotherapy to delay recurrence. We aimed to develop an individualized prediction model of early recurrence risk combining clinical and molecular factors in meningioma. Methods DNA methylation profiles of clinically annotated tumor samples across multiple institutions were used to develop a methylome model of 5-year recurrence-free survival (RFS). Subsequently, a 5-year meningioma recurrence score was generated using a nomogram that integrated the methylome model with established prognostic clinical factors. Performance of both models was evaluated and compared with standard-of-care models using multiple independent cohorts. Results The methylome-based predictor of 5-year RFS performed favorably compared with a grade-based predictor when tested using the 3 validation cohorts (ΔAUC = 0.10, 95% CI: 0.03–0.018) and was independently associated with RFS after adjusting for histopathologic grade, extent of resection, and burden of copy number alterations (hazard ratio 3.6, 95% CI: 1.8–7.2, P &lt; 0.001). A nomogram combining the methylome predictor with clinical factors demonstrated greater discrimination than a nomogram using clinical factors alone in 2 independent validation cohorts (ΔAUC = 0.25, 95% CI: 0.22–0.27) and resulted in 2 groups with distinct recurrence patterns (hazard ratio 7.7, 95% CI: 5.3–11.1, P &lt; 0.001) with clinical implications. Conclusions The models developed and validated in this study provide important prognostic information not captured by previously established clinical and molecular factors which could be used to individualize decisions regarding postoperative therapeutic interventions, in particular whether to treat patients with adjuvant radiotherapy versus observation alone. </jats:sec

Virology under the microscope—a call for rational discourse

Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns – conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we – a broad group of working virologists – seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology

A Large Late-glacial Eruption of the Hudson Volcano, Southern Chile

Lakes formed in the Aysén region of southern Chile after the retreat of mountain glaciers, beginning by at least ~17,900 cal yrs BP, contain numerous late-glacial and Holocene tephra layers derived from \u3e70 eruptions of the volcanoes in the region, including Hudson, the southernmost in the Andean Southern Volcanic Zone (SVZ). Sediment cores from six of these lakes each contain an unusually thick late-glacial age tephra layer, which based on its distribution and bulk trace-element composition was derived from a large explosive eruption of the Hudson volcano between 17,300 and 17,440 cal yrs BP, and is termed Ho. In these cores, located ~100 km northeast of Hudson, the Ho tephra layers range between 35 to 88 cm in thickness. Comparison with three previously documented large explosive Holocene Hudson eruptions (H1, H2, H3 1991 AD) suggests that Ho was larger, with an estimated tephra volume of \u3e20 km3, the largest post-glacial eruption documented for any volcano in the southern Andes. In total, Hudson has erupted ≥45 km3 of pyroclastic material in the last ~17,500 years, making it the most active volcano in the southern Andes in terms of the total volume of pyroclastic material erupted since the beginning of deglaciation in the region. Chemical stratification is not seen in the Ho deposits, but this eruption was bi-modal, with a much greater proportion of dark glassy basaltic-andesite dense fragments and pumice, which range between 55 to 59 wt % SiO2, and volumetrically less significant lighter colored dacite pumice with 66 wt % SiO2. In contrast, H1 was andesitic in composition, H2 was more felsic than H1, being composed essentially of dacite, and although H3 in 1991 AD was again bi-modal, it erupted a much smaller proportion of mafic compared to felsic material than Ho. Thus, the repetitive large explosive eruptions of Hudson volcano have evolved to progressively less mafic overall compositions from late-glacial to historic times, and their volumes have decreased. All analyzed phases of different Hudson eruptions, have similar Sr-isotopic composition (0.70444 ± 0.00007), indicating that crystal-liquid fractionation rather than crustal assimilation was the main process responsible for these chemical variations

A large late-glacial eruption of the Hudson Volcano, Southern Chile

Lakes formed in the Aysén region of southern Chile after the retreat of mountain glaciers, beginning by at least ~17,900 cal yrs BP, contain numerous late-glacial and Holocene tephra layers derived from >70 eruptions of the volcanoes in the region, including Hudson, the southernmost in the Andean Southern Volcanic Zone (SVZ). Sediment cores from six of these lakes each contain an unusually thick late-glacial age tephra layer, which based on its distribution and bulk trace-element composition was derived from a large explosive eruption of the Hudson volcano between 17,300 and 17,440 cal yrs BP, and is termed Ho. In these cores, located ~100 km northeast of Hudson, the Ho tephra layers range between 35 to 88 cm in thickness. Comparison with three previously documented large explosive Holocene Hudson eruptions (H1, H2, H3 1991 AD) suggests that Ho was larger, with an estimated tephra volume of >20 km3, the largest post-glacial eruption documented for any volcano in the southern Andes. In total, Hudson has erupted ≥45 km3 of pyroclastic material in the last ~17,500 years, making it the most active volcano in the southern Andes in terms of the total volume of pyroclastic material erupted since the beginning of deglaciation in the region. Chemical stratification is not seen in the Ho deposits, but this eruption was bi-modal, with a much greater proportion of dark glassy basaltic-andesite dense fragments and pumice, which range between 55 to 59 wt % SiO2, and volumetrically less significant lighter colored dacite pumice with 66 wt % SiO2. In contrast, H1 was andesitic in composition, H2 was more felsic than H1, being composed essentially of dacite, and although H3 in 1991 AD was again bi-modal, it erupted a much smaller proportion of mafic compared to felsic material than Ho. Thus, the repetitive large explosive eruptions of Hudson volcano have evolved to progressively less mafic overall compositions from late-glacial to historic times, and their volumes have decreased. All analyzed phases of different Hudson eruptions, have similar Sr-isotopic composition (0.70444 ± 0.00007), indicating that crystal-liquid fractionation rather than crustal assimilation was the main process responsible for these chemical variations

Eruption Record and Aspects of Magma Genesis and Evolution for Volcanoes of the Southernmost Andean Southern Volcanic Zone, Chile

Sediment cores from twelve lakes located to the east of the volcanic front of the southernmost portion of the Andean Southern Volcanic Zone (SSVZ) preserve greater than 75 late Pleistocene to Holocene tephras derived from different explosive eruptions of volcanoes in this region. Correlation of the tephra deposits and source volcano identification are based on the stratigraphic position of the tephra within the cores, tephra lithostratigraphic data (deposit thickness, grain size) and petrochemistry. Only 7 of these tephra have been previously identified in outcrops, indicating the importance of lake cores for identifying smaller eruptions. The suggested source volcanoes for these tephra include Hudson (33 events), Mentolat (18 events), Melimoyu, (4 events), and either Macá, Cay, Yanteles, or some of the many minor monogenetic eruptive centers (20 events) in the area. Hudson has been the most active volcano in SSVZ, producing greater than 45 km3 of eruptive material since the late Pleistocene. Radiocarbon age determinations on the lacustrine sediments allow for tephra age estimates using a Bayesian approach. The tephra records preserved in the lake cores and the age constraints indicate that there is no significant temporal change in the frequency of explosive eruptions associated with deglaciaiton. They also constrain changes in sedimentation rate in each lake through time, an important paleoclimate indicator. For the four southernmost volcanoes along the volcanic front in the SSVZ (Melimoyu, Mentolat, Macá and Hudson) glass compositions of melt inclusion from olivine phenocrysts found in the tephras are used to constrain primitive magma compositions and melt generation parameters such as slab surface temperatures, fraction of mantle melting and mantle water content. The results indicate that magma compositions and melting parameters are similar along the arc front below Melimoyu, Macá, and Hudson, but distinct below Mentolat. These differences may be generated at the source region above the subducted slab, and in the case of Mentolat, may be related to a subducted Nazca Plate fracture zone that projects beneath this center and can transport greater amounts of hydrous phases, seawater and sediments into the sub-arc mantle