952 research outputs found

    Satellite data support to the PRE-STORM operations center, May-June 1985

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    September 1985.Includes bibliographical references.The activities of CIRA are described with regard to satellite support of the field phase of the Oklahoma-Kansas PRE-STORM experiment, and to the ongoing research projects which make use of PRE-STORM data sets. Routine GOES imagery and VAS products were displayed on a personal computer (PC) workstation located in the PRE-STORM operations support facility. Half-hourly visible and infrared imagery, two-hourly water vapor imagery, and a number of derived VAS sounding products were available in real-time. The impact of the PC workstation on PRESTORM operations is discussed. The image display and analysis products, and VAS data products for use on the PC workstation are described in detail. Finally, PC data archival procedures and preliminary plans for future research are presented.This Report was supported under NOAA Grants - #NA84AA-D-00017 - Mesoscale Analysis and Forecast Product Development for Severe Storm Nowcasting and #NA84AA-H-00020 - Research and Development Activities in Support of the NOAA Operational VAS Assessment (NOVA) Program

    NPC 15669 blocks neutrophil CD18 increase and lung injury during cardiopulmonary bypass in pigs

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    During cardiopulmonary bypass (CPB), neutrophils become activated due to contact with extracorporeal surfaces and binding of complement fragments C3a and C5a, leading to extravasation and subsequent tissue damage. In this study, the effects of the leumedin NPC 15669 (N [9H - (2,7 dimethylfluorenyl - 9 - methoxy) car bonyl]-L-leucine), a leukocyte recruitment inhibitor, were evaluated in a pig model of CPB. NPC 15669 caused significant inhibition of CPB associated increase in CD18 upregulation, lung tissue myeloperoxidase content, and percentage wet weight compared to controls. Lung histology revealed clear airways and minimal neutrophil infiltration in treated animals vs. significant oedema and cellular infiltration in controls. It is concluded that CPB causes a dramatic increase in neutrophil CD18, and that leumedins are effective in inhibiting neutrophil activation and subsequent tissue injury when administered during CPB

    Light and depth dependency of nitrogen fixation by the non‐photosynthetic, symbiotic cyanobacterium UCYN‐A

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    The symbiotic cyanobacterium UCYN-A is one of the most globally abundant marine dinitrogen (N2)-fixers, but cultures have not been available and its biology and ecology are poorly understood. We used cultivation-independent approaches to investigate how UCYN-A single-cell N2 fixation rates (NFRs) and nifH gene expression vary as a function of depth and photoperiod. Twelve-hour day/night incubations showed that UCYN-A only fixed N2 during the day. Experiments conducted using in situ arrays showed a light-dependence of NFRs by the UCYN-A symbiosis, with the highest rates in surface waters (5–45 m) and lower rates at depth (≄ 75 m). Analysis of NFRs versus in situ light intensity yielded a light saturation parameter (Ik) for UCYN-A of 44 Όmol quanta m−2 s−1. This is low compared with other marine diazotrophs, suggesting an ecological advantage for the UCYN-A symbiosis under low-light conditions. In contrast to cell-specific NFRs, nifH gene-specific expression levels did not vary with depth, indicating that light regulates N2 fixation by UCYN-A through processes other than transcription, likely including host–symbiont interactions. These results offer new insights into the physiology of the UCYN-A symbiosis in the subtropical North Pacific Ocean and provide clues to the environmental drivers of its global distributions.En prens

    Neutron skin of 208^{208}Pb from Coherent Pion Photoproduction

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    Information on the size and shape of the neutron skin on 208^{208}Pb has been extracted from coherent pion photoproduction cross sections measured using the Crystal Ball together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections the half-height radius and diffuseness of the neutron distribution are found to be 6.70±0.03(stat)\pm 0.03(stat) fm and 0.55±0.01(stat)\pm 0.01(stat)−0.03+0.02(sys)^{+0.02}_{-0.03}(sys) fm respectively, corresponding to a neutron skin thickness Δrnp\Delta r_{np}=0.15±0.03(stat)\pm 0.03(stat)−0.03+0.01(sys)^{+0.01}_{-0.03}(sys) fm. The results give the first successful extraction of a neutron skin with an electromagnetic probe and indicate the skin of 208^{208}Pb has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.Comment: 4 figures 5 pages. Version submitted to journal. Includes additional studies of systematic effects in the extracted diffuseness, which led to a small increase in the quoted systematic error. These additional studies are discussed in the revised manuscript. Also includes minor editorial improvements to the tex

    Toxicity and recovery in the pregnant mouse after gestational exposure to the cyanobacterial toxin, cylindrospermopsin

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    Cylindrospermopsin (CYN) is a tricyclic alkaloid toxin produced by fresh water cyanobacterial species worldwide. CYN has been responsible for both livestock and human poisoning after oral exposure. This study investigated the toxicity of CYN to pregnant mice exposed during different segments of gestation. The course of recovery and individual responses to the toxin were evaluated. Adverse effects of CYN were monitored up to 7 weeks post-dosing by clinical examination, histopathology, biochemistry and gene expression. Exposure on gestational days (GD) 8–12 induced significantly more lethality than GD13–17 exposure. Periorbital, gastrointestinal and distal tail hemorrhages were seen in both groups. Serum markers indicative of hepatic injury (alanine amino transferase, aspartate amino transferase and sorbitol dehydrogenase)were increased in both groups; markers of renal dysfunction (blood urea nitrogen and creatinine) were elevated in the GD8–12 animals. Histopathology was observed in the liver (centrilobular necrosis) and kidney (interstitial inflammation) in groups exhibiting abnormal serum markers. The expression profiles of genes involved in ribosomal biogenesis, xenobiotic and lipid metabolism, inflammatory response and oxidative stress were altered 24 h after the final dose. One week after dosing, gross, histological and serum parameters had returned to normal, although increased liver/body weight ratio and one instance of gastrointestinal bleeding was found in the GD13–17 group. Gene expression changes persisted up to 2 weeks post-dosing and returned to normal by 4 weeks. Responses of individual animals to CYN exposure indicated highly significant inter-animal variability within the treated groups

    Determination of the Dalitz plot parameter alpha for the decay eta->3pi^0 with the Crystal Ball at MAMI-B

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    A precise measurement of the Dalitz plot parameter, alpha, for the eta->3pi^0 decay is presented. The experiment was performed with the Crystal Ball and TAPS large acceptance photon detectors at the tagged photon beam facility of the MAMI-B electron accelerator in Mainz. High statistics of 1.8*10^6 eta->3pi^0 events were obtained, giving the result alpha = -0.032 +/- 0.002(stat) +/- 0.002(syst).Comment: 9 pages, 6 figures, published in the online-first section of EPJ A, included changes referees asked for, added DO

    Nitrogen fixation and transfer in open ocean diatom–cyanobacterial symbioses

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    Many diatoms that inhabit low-nutrient waters of the open ocean live in close association with cyanobacteria. Some of these associations are believed to be mutualistic, where N2-fixing cyanobacterial symbionts provide N for the diatoms. Rates of N2 fixation by symbiotic cyanobacteria and the N transfer to their diatom partners were measured using a high-resolution nanometer scale secondary ion mass spectrometry approach in natural populations. Cell-specific rates of N2 fixation (1.15–71.5 fmol N per cell h−1) were similar amongst the symbioses and rapid transfer (within 30 min) of fixed N was also measured. Similar growth rates for the diatoms and their symbionts were determined and the symbiotic growth rates were higher than those estimated for free-living cells. The N2 fixation rates estimated for Richelia and Calothrix symbionts were 171–420 times higher when the cells were symbiotic compared with the rates estimated for the cells living freely. When combined, the latter two results suggest that the diatom partners influence the growth and metabolism of their cyanobacterial symbionts. We estimated that Richelia fix 81–744% more N than needed for their own growth and up to 97.3% of the fixed N is transferred to the diatom partners. This study provides new information on the mechanisms controlling N input into the open ocean by symbiotic microorganisms, which are widespread and important for oceanic primary production. Further, this is the first demonstration of N transfer from an N2 fixer to a unicellular partner. These symbioses are important models for molecular regulation and nutrient exchange in symbiotic systems

    High Quality, Low Cost Egg Incubator for BIC Church in Choma, Zambia

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    The Egg Incubator team is partnering with the Brethren in Christ Church located in Choma, Zambia to design a high-quality, low-cost chicken egg incubator to supply the pastors and church members with a means of food and income. The design will need to take into account the accessibility and cost of the tools and materials. The current prototype features separate heating and humidity systems, a control system to maintain a set temperature and humidity, and tilting egg racks. The heating system consists of two stovetop coils to produce heat and a fan to transfer it to the air. The humidifier utilizes an atomizer in a pan of water to create a mist that mixes with the hot air to create humidity. The control system uses a proportional integral derivative controller (PID) to keep the temperature at 37 ± 1 °C and the humidity at 60–70%. The egg racks are tilted by a motor that runs every 6 hours to prevent the embryos from sticking to the shell. With a fully functioning prototype, the team has begun to incubate 60 real fertilized eggs. During the 21-day incubation process, a final prototype iteration is being designed and will be built on-site in Zambia in May 2022. Funding for this work provided by The Collaboratory for Strategic Partnerships and Applied Research.https://mosaic.messiah.edu/engr2022/1004/thumbnail.jp

    Differential distributions of Synechococcus subgroups across the California current system

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    Synechococcus is an abundant marine cyanobacterial genus composed of different populations that vary physiologically. Synechococcus narB gene sequences (encoding for nitrate reductase in cyanobacteria) obtained previously from isolates and the environment (e.g., North Pacific Gyre Station ALOHA, Hawaii or Monterey Bay, CA, USA) were used to develop quantitative PCR (qPCR) assays. These qPCR assays were used to quantify populations from specific narB phylogenetic clades across the California Current System (CCS), a region composed of dynamic zones between a coastal-upwelling zone and the oligotrophic Pacific Ocean. Targeted populations (narB subgroups) had different biogeographic patterns across the CCS, which appear to be driven by environmental conditions. Subgroups CC1, DC1, and DC2 were abundant in coastal-upwelling to coastal-transition zone waters with relatively high to intermediate ammonium, nitrate, and chl. a concentrations. Subgroups AC1 and FC1 were most abundant in coastal-transition zone waters with intermediate nutrient concentrations. EO1 and GO1 were most abundant at different depths of oligotrophic open-ocean waters (either in the upper mixed layer or just below). EO1, AC1, and FC1 distributions differed from other narB subgroups and likely possess unique ecologies enabling them to be most abundant in waters between coastal and open-ocean waters. Different CCS zones possessed distinct Synechococcus communities. Core California current water possessed low numbers of narB subgroups relative to counted Synechococcus cells, and coastal-transition waters contained high abundances of Synechococcus cells and total number of narB subgroups. The presented biogeographic data provides insight on the distributions and ecologies of Synechococcus present in an eastern boundary current system. © 2011 Paerl, Johnson, Welsh, Worden, Chavez and Zehr
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