Sphenothallus-Like Fossils from the Martinsburg Formation (Upper Ordovician), Tennessee, USA

Tubular fossils, up to 2 mm in diameter and 60 mm in length, occur rarely in the upper Martinsburg Formation (Upper Ordovician), northeastern Tennessee Appalachians, U.S.A. The fossils are unbranched, straight or slightly bent, occasionally twisted and wrinkled, and not significantly tapered. Orientation of the fossils within shallow-marine tempestites suggests that they represent remains of organisms that were broken, transported, and deposited by storm waves and currents. The fossils are morphologically similar to many of the previously identified species belonging to the genus Sphenothallus, a relatively rare tube-dwelling Paleozoic marine invertebrate. Owing to the limited evidence for distal widening of the tubes, lack of holdfasts, and carbonaceous rather than phosphatic composition, the affinity of these fossils remains uncertain, and we refer to them as Sphenothallus-like

Enabling real-time multi-messenger astrophysics discoveries with deep learning

Multi-messenger astrophysics is a fast-growing, interdisciplinary field that combines data, which vary in volume and speed of data processing, from many different instruments that probe the Universe using different cosmic messengers: electromagnetic waves, cosmic rays, gravitational waves and neutrinos. In this Expert Recommendation, we review the key challenges of real-time observations of gravitational wave sources and their electromagnetic and astroparticle counterparts, and make a number of recommendations to maximize their potential for scientific discovery. These recommendations refer to the design of scalable and computationally efficient machine learning algorithms; the cyber-infrastructure to numerically simulate astrophysical sources, and to process and interpret multi-messenger astrophysics data; the management of gravitational wave detections to trigger real-time alerts for electromagnetic and astroparticle follow-ups; a vision to harness future developments of machine learning and cyber-infrastructure resources to cope with the big-data requirements; and the need to build a community of experts to realize the goals of multi-messenger astrophysics

Living God Pandeism: Evidential Support

Pandeism is the belief that God chose to wholly become our Universe, imposing principles at this Becoming that have fostered the lawful evolution of multifarious structures, including life and consciousness. This article describes and defends a particular form of pandeism: living God pandeism (LGP). On LGP, our Universe inherits all of God's unsurpassable attributes—reality, unity, consciousness, knowledge, intelligence, and effectiveness—and includes as much reality, conscious and unconscious, as is possible consistent with retaining those attributes. God and the Universe, together “God-and-Universe,” is also eternal into the future and the past. The article derives testable hypotheses from these claims and shows that the evidence to date confirms some of these while falsifying none. Theism cannot be tested in the same way

Geochemical investigation of weathering in a high arctic watershed and provenance of ssediments in Kongressvatnet, Svalbard, Norway

This study uses changes in the chemistry and mineralogy of lake and surface sediments in a small lake in Kongress Valley (Kongressdalen), to interpret Late Holocene climate change in Western Spitsbergen, Svalbard. Changes in clay mineralogy across an inactive outwash fan (Black Fan) in the valley reflect weathering since the fan\u27s formation during the Little Ice Age (LIA) (1550-1920). X-Ray Diffraction analysis of clay samples from the meltwater channels and the Kapp Starostin rocks that compose the fan reveal a strong 10 Å peak, unaffected by ethylene glycol solvation or heating to 375 °C and 550 °C, indicative of illite. However, samples collected from vegetated debris flows between the meltwater channels reveal a diminished 10 Å phase and a slightly expandable peak at approximately 14 Å, unaffected by magnesium and glycerol saturation (d 060 of 1.54 Å), indicative of vermiculite. The inverse relationship between these peaks reflects the weathering of illite to vermiculite, suggesting an early period of Kapp Starostin Fm. deposition subsequently eroded by meltwater from Kongressbreen (glacier) during the LIA. Changes in lake sediment chemistry should reflect changing sources of sediment inflow as meltwater from an advancing ice activated the Black Fan. X-Ray Fluorescence analysis of the White and Black Fan, which are the two principle sources of sediment inflow to the lake, reveals that the Black Fan sediments have greater concentrations of K2O, Fe2O3, Zr, and Cr, while the White Fan is characterized by higher concentrations of MgO, CaO, Sr, and U. However, analysis of sediment cores from the central part of the lake reveals a chemical composition that resembles only that of the White Fan sediment, indicating almost no Black Fan input into Kongressvatnet. The most likely hypothesis to explain this absence is that Kongressbreen was a cold-based glacier and therefore did not produce fine glacial flour from bedrock scour. Despite the dominant White Fan signature in the core sediments, ITRAX Scanning XRay Fluorescence analysis reveals significant variations in core chemistry with depth, which is likely due to changes in climate. Periodic, massive high calcium layers, lacking internal laminations, characterize the upper 200 mm of the core, which correlates using MS to cores dated to the LIA (Guilizzoni et al., 2006). Preliminary SEM analysis reveals the presence of euhedral, sharp-edged rhombohedra and fibrous needles of calcite, high-Mg calcite, and dolomite, suggesting the precipitation of carbonate. The current supersaturation of Kongressvatnet waters below the chemocline with respect to calcite further supports this hypothesis. Alternatively, periods of extended ice cover during which the formation of lake ice concentrates the calcium in the underlying lake water, and may result in the formation of cryogenic calcite. Anomalous peaks in iron and sulfur characterize the lower portion of the core (300-400 mm), which MS correlations indicate corresponds to the Medieval Warm Period (Guilizzoni et al., 2006). An increase in organic terriginous inflow or lake productivity during this period likely spurs the activity of sulfur reducing bacteria, resulting in reducing conditions and the precipitation of iron sulfides. This analysis suggests that although provenance cannot be used in Kongressvatnet to constrain the timing of the Little Ice Age, changes in climate are intimately associated with fluctuations in lake chemistry and the lake\u27s biogeochemical cycles, providing the opportunity to interpret past climate change from lake sediment chemistry

Partitioning of Polybrominated Diphenyl Ethers to Dissolved Organic Matter Isolated From Arctic Surface Waters.

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant that is distally transported to the Arctic. Little is known about the fate of PBDEs in Arctic surface waters, especially in the presence of dissolved organic matter (DOM). DOM has been shown to interact with hydrophobic organic contaminants and can alter their mobility, bioavailability, and degradation in the environment. In this study, the partitioning of six PBDE congeners between Arctic DOM (isolated via solid phase extraction) and water was measured using the aqueous solubility enhancement method. Measured dissolved organic carbon (DOC)–water partition coefficient (KDOC) values were nearly an order of magnitude lower than previously reported values for the same PBDE congeners in soil or commercial organic matter, ranging from 103.97 to 105.16 L kg–1 of organic carbon. Measured results compared favorably with values calculated using polyparameter linear free energy models for Suwannee River fulvic acid. Log KDOC values increased with increasing PBDE hydrophobicity. Slightly lower than expected values were observed for the highest brominated congeners, which we attribute to steric hindrance. This study is the first to comprehensively measure KDOC values for a range of PBDE congeners with DOM isolated from Arctic surface waters

A Fluence-Based Method for the Direct Comparison of Photolysis Kinetics under Variable Light Regimes

Chemical actinometers are traditionally used to account for photochemical experiments conducted under different light regimes (simulated vs natural; also seasonal, daytime, cloud cover, and latitude changes). Their many limitations and the lack of a universally applicable actinometer demand development of a new approach for studying environmentally relevant photochemical processes in sunlight. We suggest the use of fluence-based rate constants (converted to time-based rate constants and half-lives with irradiance normalization), using a data-logging radiometer to track the accumulated dose of UVA and UVB radiation. Our results suggest that this method can effectively account for minor changes in cloud cover and sun angle in the photolysis of <i>p</i>-nitroanisole/pyridine and <i>p</i>-nitroacetophenone/pyridine. The greatest error is caused by factors (e.g., dense cloud cover, extreme sun angles, and changes in ozone) that affect relative UVA and UVB fluence. We believe that this simple and elegant method serves as an important bridge between laboratory and field-based environmental photochemistry experiments

A Fluence-Based Method for the Direct Comparison of Photolysis Kinetics under Variable Light Regimes

Chemical actinometers are traditionally used to account for photochemical experiments conducted under different light regimes (simulated vs natural; also seasonal, daytime, cloud cover, and latitude changes). Their many limitations and the lack of a universally applicable actinometer demand development of a new approach for studying environmentally relevant photochemical processes in sunlight. We suggest the use of fluence-based rate constants (converted to time-based rate constants and half-lives with irradiance normalization), using a data-logging radiometer to track the accumulated dose of UVA and UVB radiation. Our results suggest that this method can effectively account for minor changes in cloud cover and sun angle in the photolysis of <i>p</i>-nitroanisole/pyridine and <i>p</i>-nitroacetophenone/pyridine. The greatest error is caused by factors (e.g., dense cloud cover, extreme sun angles, and changes in ozone) that affect relative UVA and UVB fluence. We believe that this simple and elegant method serves as an important bridge between laboratory and field-based environmental photochemistry experiments

Partitioning of Polybrominated Diphenyl Ethers to Dissolved Organic Matter Isolated from Arctic Surface Waters

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant that is distally transported to the Arctic. Little is known about the fate of PBDEs in Arctic surface waters, especially in the presence of dissolved organic matter (DOM). DOM has been shown to interact with hydrophobic organic contaminants and can alter their mobility, bioavailability, and degradation in the environment. In this study, the partitioning of six PBDE congeners between Arctic DOM (isolated via solid phase extraction) and water was measured using the aqueous solubility enhancement method. Measured dissolved organic carbon (DOC)–water partition coefficient (<i>K</i>_DOC) values were nearly an order of magnitude lower than previously reported values for the same PBDE congeners in soil or commercial organic matter, ranging from 10^3.97 to 10^5.16 L kg^–1 of organic carbon. Measured results compared favorably with values calculated using polyparameter linear free energy models for Suwannee River fulvic acid. Log <i>K</i>_DOC values increased with increasing PBDE hydrophobicity. Slightly lower than expected values were observed for the highest brominated congeners, which we attribute to steric hindrance. This study is the first to comprehensively measure <i>K</i>_DOC values for a range of PBDE congeners with DOM isolated from Arctic surface waters

Sphenothallus

Tubular fossils, up to 2 mm in diameter and 60 mm in length, occur rarely in the upper Martinsburg Formation (Upper Ordovician), northeastern Tennessee Appalachians, U.S.A. The fossils are unbranched, straight or slightly bent, occasionally twisted and wrinkled, and not significantly tapered. Orientation of the fossils within shallow-marine tempestites suggests that they represent remains of organisms that were broken, transported, and deposited by storm waves and currents. The fossils are morphologically similar to many of the previously identified species belonging to the genus Sphenothallus, a relatively rare tube-dwelling Paleozoic marine invertebrate. Owing to the limited evidence for distal widening of the tubes, lack of holdfasts, and carbonaceous rather than phosphatic composition, the affinity of these fossils remains uncertain, and we refer to them as Sphenothallus-like