Mollusks from Wisconsinan (Pleistocene) ice-contact sediments of the Missouri Coteau in central North Dakota

This thesis here abstracted was written under the direction of Frank D. Holland, Jr. and was approved by Wilson M. Laird and George C. Wheeler as members of the examining committee, of which Dr. Holland was Chairman. Geologic and paleontologic evidence indicates that numerous mesotropic, temperate, water bodies were present while drift-covered bloacks of stagnant glacier ice, unplaced during Woodfordian (late Wisconsinan, Pleistocene) time, underlay the Missouri Coteau district (approximately 50 by 300 miles in extent) in central North Dakota. Fossil mollusks, contained in sediments deposited in contact with the stagnant ice at 40 sites, are represented by 23 species including polecypods of the families Unionidae and Sphaeriidae and gastropods of the families Valvatidae, Hydrobiidae, Physidae, Lymnaeidae, Planorbidae, Ancylidae, Succineidae, and Pupillidae. ____ shells have provided material for five radiocarbon dates in the Missouri Coteau district which indicate the melting of the stagnant ice may have required 2,100 years. The fossil mollusks, as now known, do not serve as stratigraphic indicies to the late Pleistocene deposits of the region, but the species composition of fossil Mollusca communities dominated by the branchiate genera Valvata and Amnicola is required as tentative evidence of the pre-_____ age of the Missouri Coteau sediments. The mollusks also indicate the climate of the region to have been mild and humid as early as 12,000 and as late as 8,700 radiocarbon years before the present

A Comparison of the Late Wisconsinan Molluscan Fauna of the Missouri Coteau District (North Dakota) with a Modern Alaskan Analogue

Study of forty fossiliferous sites in late Wisconsinan sediments from the Missouri Coteau district in central North Dakota has defined the molluscan fauna of the period of geologic time between 12,000 and 9,000 C14 years before the present. The fauna includes twenty-eight taxa of nonmarine gastropods and bivalves and is dominated by branchiates. The modern molluscan fauna of the Missouri Coteau district in North Dakota lacks four species which were resident in the late Wisconsinan and contains no unionids, one additional aquatic species, and is strongly dominated by pulmonate gastropods. The geology of the Missouri Coteau has been interpreted as being the sedimentary result of the stagnation of the marginal fifty to one hundred miles of the Wisconsinan ice sheet. The interpretation of the paleoecology of the late Wisconsinan molluscan fauna derives from geologic, paleoautecologic, and paleosynecologic data. It is hypothesized that at the time the late Wisconsinan continental ice sheet stagnated in central North Dakota, the climate was less extreme and more humid than at present. Ponds and streams existed on the ice-cored topography of the Missouri Coteau. They were connected by a drainage system tributary to the Missouri River and populated by an abundant, branchiate-dominated molluscan fauna. Fishes, probably of the families Percidae and Centrarchidae, lived in the ponds and rivers and unionid bivalves successfully populated many of the water bodies. Calcareous algae (Chara) and undoubtedly other species of aquatic vegetation colonized the clear, warm water of the drainage system. The ice-basined, drift-insulated lake was the most common lithotope in which fossil mollusks were preserved. The entire drainage system was supplied by greater rainfall and snowmelt than now occurs on the Missouri Coteau (probably in the order of 20 to 30 inches per year) and the precipitation - evapotranspiration ratio was positive. The humid climate changed toward the more arid climate of today before the ice core of the Coteau melted. Comparison with modern molluscan assemblages characteristic of defined habitats in Minnesota indicates that the mollusks which lived on the ice-cored Missouri Coteau, could have occupied small streams, medium-hardwater lakes, and/or hardwater prairie lakes. In consideration of the population dominance by branchiates, I believe that hard water prairie lakes are not likely to have occurred on the late Wisconsinan Missouri Coteau. In order to evaluate this hypothesis the terminus of the Martin River Glacier in south-central Alaska was studied. A molluscan fauna of ten fresh-water and thirteen terrestrial taxa was discovered on and in front of the stagnant terminus of the glacier. Twenty-three potential habitats for mollusks were studied and defined. Twelve of these were found to contain mollusks. The aquatic mollusks were found to occupy cool water (as low as 5°C) and warm water (above 10°C) and to be able to withstand very low concentrations of dissolved solids and high turbidity. Branchiate gastropods and bivalves were found to favor turbid environments next to the glacier and to populate successfully ice-basined, clear, warm lakes on the glacier. Terrestrial snails and slugs were found as much as a kilometer out on the drift-covered stagnant glacial terminus separated from the glacier ice by only 11 inches of alder-leaf-litter. Terrestrial snails were found in spruce forests only once. They were not found under willow bushes, young alder shrubs (less than 7 years in age), or on outwash gravel surfaces. Acid peat growths, and ponds developed in them, were also barren of mollusks. Edaphic conditions are assumed to account for their absence in these potential habitats. The Alaskan studies lend credence to the hypothesis erected to explain the paleoecology of the late Wisconsinan molluscan fauna of the Missouri Coteau in that they prove that mollusks are vigorous pioneers near and on stagnating glaciers, that less than a foot of super glacial drift is sufficient to insulate terrestrial molluscan habitats, and that six feet of superglacial drift is sufficient to insulate ice-basined, clear, warm lakes from their containing ice walls. The studies further emphasize that terminal glacial features such as end moraines, outwash fans, dead-ice moraines, kettles, and superglacial lakes are the result of a non-glacial climate and the inference of glacial climate from such features is a fundamental error. The employment of fossil nonmarine mollusks as indicators of past water quality was brought under serious question by the studies reported here. The fact that aquatic mollusks live successfully in Alaskan waters which contain less than 1 ppm dissolved solids brings into question the practice of employing mollusks as paleolimnologic indicators of chemical aspects of their environments. I believe the use of mollusks as indicators of past water quality of their habitats must be discontinued

Preliminary report of the molluscan fauna of the Martin River Glacier and associated area (South-Central Alaska)

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Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial.

BACKGROUND: The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might be curtailed by vaccination. We assessed the safety, reactogenicity, and immunogenicity of a viral vectored coronavirus vaccine that expresses the spike protein of SARS-CoV-2. METHODS: We did a phase 1/2, single-blind, randomised controlled trial in five trial sites in the UK of a chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19) expressing the SARS-CoV-2 spike protein compared with a meningococcal conjugate vaccine (MenACWY) as control. Healthy adults aged 18-55 years with no history of laboratory confirmed SARS-CoV-2 infection or of COVID-19-like symptoms were randomly assigned (1:1) to receive ChAdOx1 nCoV-19 at a dose of 5 × 1010 viral particles or MenACWY as a single intramuscular injection. A protocol amendment in two of the five sites allowed prophylactic paracetamol to be administered before vaccination. Ten participants assigned to a non-randomised, unblinded ChAdOx1 nCoV-19 prime-boost group received a two-dose schedule, with the booster vaccine administered 28 days after the first dose. Humoral responses at baseline and following vaccination were assessed using a standardised total IgG ELISA against trimeric SARS-CoV-2 spike protein, a muliplexed immunoassay, three live SARS-CoV-2 neutralisation assays (a 50% plaque reduction neutralisation assay [PRNT50]; a microneutralisation assay [MNA50, MNA80, and MNA90]; and Marburg VN), and a pseudovirus neutralisation assay. Cellular responses were assessed using an ex-vivo interferon-γ enzyme-linked immunospot assay. The co-primary outcomes are to assess efficacy, as measured by cases of symptomatic virologically confirmed COVID-19, and safety, as measured by the occurrence of serious adverse events. Analyses were done by group allocation in participants who received the vaccine. Safety was assessed over 28 days after vaccination. Here, we report the preliminary findings on safety, reactogenicity, and cellular and humoral immune responses. The study is ongoing, and was registered at ISRCTN, 15281137, and ClinicalTrials.gov, NCT04324606. FINDINGS: Between April 23 and May 21, 2020, 1077 participants were enrolled and assigned to receive either ChAdOx1 nCoV-19 (n=543) or MenACWY (n=534), ten of whom were enrolled in the non-randomised ChAdOx1 nCoV-19 prime-boost group. Local and systemic reactions were more common in the ChAdOx1 nCoV-19 group and many were reduced by use of prophylactic paracetamol, including pain, feeling feverish, chills, muscle ache, headache, and malaise (all p<0·05). There were no serious adverse events related to ChAdOx1 nCoV-19. In the ChAdOx1 nCoV-19 group, spike-specific T-cell responses peaked on day 14 (median 856 spot-forming cells per million peripheral blood mononuclear cells, IQR 493-1802; n=43). Anti-spike IgG responses rose by day 28 (median 157 ELISA units [EU], 96-317; n=127), and were boosted following a second dose (639 EU, 360-792; n=10). Neutralising antibody responses against SARS-CoV-2 were detected in 32 (91%) of 35 participants after a single dose when measured in MNA80 and in 35 (100%) participants when measured in PRNT50. After a booster dose, all participants had neutralising activity (nine of nine in MNA80 at day 42 and ten of ten in Marburg VN on day 56). Neutralising antibody responses correlated strongly with antibody levels measured by ELISA (R2=0·67 by Marburg VN; p<0·001). INTERPRETATION: ChAdOx1 nCoV-19 showed an acceptable safety profile, and homologous boosting increased antibody responses. These results, together with the induction of both humoral and cellular immune responses, support large-scale evaluation of this candidate vaccine in an ongoing phase 3 programme. FUNDING: UK Research and Innovation, Coalition for Epidemic Preparedness Innovations, National Institute for Health Research (NIHR), NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and the German Center for Infection Research (DZIF), Partner site Gießen-Marburg-Langen

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8-m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, plus integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, beam combiners enabling long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of 1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc., 2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and 3) efficient integration of photonics with detectors. In this roadmap, we identify 23 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries