Field Measurements of Terrestrial and Martian Dust Devils

Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types

Physical Processes in Star Formation

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio

Universal DNA methylation age across mammalian tissues

DATA AVAILABILITY STATEMENT : The individual-level data from the Mammalian Methylation Consortium can be accessed from several online locations. All data from the Mammalian Methylation Consortium are posted on Gene Expression Omnibus (complete dataset, GSE223748). Subsets of the datasets can also be downloaded from accession numbers GSE174758, GSE184211, GSE184213, GSE184215, GSE184216, GSE184218, GSE184220, GSE184221, GSE184224, GSE190660, GSE190661, GSE190662, GSE190663, GSE190664, GSE174544, GSE190665, GSE174767, GSE184222, GSE184223, GSE174777, GSE174778, GSE173330, GSE164127, GSE147002, GSE147003, GSE147004, GSE223943 and GSE223944. Additional details can be found in Supplementary Note 2. The mammalian data can also be downloaded from the Clock Foundation webpage: https://clockfoundation.org/MammalianMethylationConsortium. The mammalian methylation array is available through the non-profit Epigenetic Clock Development Foundation (https://clockfoundation.org/). The manifest file of the mammalian array and genome annotations of CpG sites can be found on Zenodo (10.5281/zenodo.7574747). All other data supporting the findings of this study are available from the corresponding author upon reasonable request. The chip manifest files, genome annotations of CpG sites and the software code for universal pan-mammalian clocks can be found on GitHub95 at https://github.com/shorvath/MammalianMethylationConsortium/tree/v2.0.0. The individual R code for the universal pan-mammalian clocks, EWAS analysis and functional enrichment studies can be also found in the Supplementary Code.SUPPLEMENTARY MATERIAL 1 : Supplementary Tables 1–3 and Notes 1–6.SUPPLEMENTARY MATERIAL 2 : Reporting SummarySUPPLEMENTARY MATERIAL 3 : Supplementary Data 1–14.SUPPLEMENTARY MATERIAL 4 : Supplementary Code.Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.https://www.nature.com/nataginghj2024Zoology and EntomologySDG-15:Life on lan

The climatic consequences of a rare orbital anomaly at the Oligocene/Miocene boundary (23Ma)

The late Oligocene to early Miocene (20-26Ma) is characterized by a complex climate history that includes a stepped transition toward a cooler climate, intermittent partial glaciations of Antarctica, and a transient glaciation, Mi-1, at the Oligocene/Miocene (O/M) boundary. The Mi-1 event is characterized by an anomalous positive oxygen isotope excursion, the magnitude of which suggests the brief appearance of a full-scale ice-sheet on east Antarctica coupled with a few degrees of deep sea cooling. A recent breakthrough in extending the astronomical calibration back to ~30 Ma has provided a unique opportunity to compare the climatic events of the O/M transition relative to Earth’s orbital variations. Here, we present an uninterrupted 5.5 My long high-fidelity chronology of late Oligocene-early Miocene climate and ocean carbon chemistry that is based on a composite in the western equatorial Atlantic. This unique isotope record provides a rare window into how the climate system responded to orbital forcing uncer boundary conditions significantly different from those of the recent past. Time-series analyses reveal climate variance concentrated at all Milankovitch frequencies, but with unusually strong power at the primary eccentricity band periods of 406, 125, and 95-ky. These cycles, which represent in part glacial advances and retreats of Antarctic ice-sheets, show significantly enhanced variability over a 1.6 my period (21.4-23.0 Ma) of suspected low greenhouse gas levels as inferred from the carbon isotope record. Perhaps the most unexpected finding is that of a rare orbital congruence between eccentricity and obliquity that precisely corresponds with the Mi-1 glaciation. This orbital anomaly involves ~four consecutive cycles of low amplitude variance in obliquity (a node) during a period of low eccentricity. The net result is an extended period (~200ky) of low seasonality orbits, which allows for a step-like expansion of an Antarctic ice-sheet

Climate response to orbital forcing across the Oligocene-Miocene boundary

Spectral analyses of an uninterrupted 5.5-million-year (My)-long chronology of late Oligocene-early Miocene climate and ocean carbon chemistry from two deep-sea cores recovered in the western equatorial Atlantic reveal variance concentrated at all Milankovitch frequencies. Exceptional spectral power in climate is recorded at the 406-thousand-year (ky) period eccentricity band over a 3.4-million-year period [20 to 23.4 My ago (Ma)] as well as in the 125- and 95-ky bands over a 1.3-million-year period (21.7 to 23.0 Ma) of suspected low greenhouse gas levels. Moreover, a major transient glaciation at the epoch boundary (~23 Ma), Mi-1, corresponds with a rare orbital congruence involving obliquity and eccentricity. The anomaly, which consists of low-amplitude variance in obliquity (a node) and a minimum in eccentricity, results in an extended period (~200 ky) of low seasonality orbits favorable to ice-sheet expansion on Antarctic

Provenance of freshwater pulses in the Gulf of Mexico during the last deglaciation

International audienceDuring the last deglaciation, the decaying Laurentide Ice Sheet (LIS) delivered huge volumes of meltwater toward the Gulf of Mexico. The present investigation of clay mineralogy and grain-size characteristics of terrigenous sediments deposited in the Orca Basin (Gulf of Mexico) offers a unique opportunity to link the marine record of these meltwater floods with the reconstructed continental glacial history and the modeled drainage patterns. Five peculiar sedimentary levels, characterized by high smectite content and low CaCO3 content, were identified and occurred simultaneously with major meltwater floods. According to recently published clay mineral distribution maps for North America, these results help to pinpoint the southwestern margin of the LIS as a main contributor to most of the meltwater discharges. In addition, the peculiar mineralogical composition (illite and chlorite-rich) of the sediments characterizing the meltwater episode associated with Heinrich event 1 suggests a provenance from the Great Lakes area, supporting the interpretation of destabilization of the LIS southeastern margin during this event. Decreased terrigenous contribution associated with changing provenance of sediments after 12.9 cal ka BP suggests strong modifications of the continental hydrography in relation to Lake Agassiz history and changes in the morphology of Mississippi delta due to rising sea level