Frontal subduction of the Mid-Atlantic Bight shelf water at the onshore edge of a warm-core ring

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans, 123(11), (2018): 7795-7818. doi: 10.1029/2018JC013794.This work studies the subduction of the shelf water along the onshore edge of a warm‐core ring that impinges on the edge of the Mid‐Atlantic Bight continental shelf. The dynamical analysis is based on observations by satellites and from the Ocean Observatories Initiative Pioneer Array observatory as well as idealized numerical model simulations. They together show that frontogenesis‐induced submesoscale frontal subduction with order‐one Rossby and Froude numbers occurs on the onshore edge of the ring. The subduction flow results from the onshore migration of the warm‐core ring that intensifies the density front on the interface of the ring and shelf waters. The subduction is a part of the cross‐front secondary circulation trying to relax the intensifying density front. The dramatically different physical and biogeochemical properties of the ring and shelf waters provide a great opportunity to visualize the subduction phenomenon. Entrained by the ring‐edge current, the subducted shelf water is subsequently transported offshore below a surface layer of ring water and alongside of the surface‐visible shelf‐water streamer. It explains the historical observations of isolated subsurface packets of shelf water along the ring periphery in the slope sea. Model‐based estimate suggests that this type of subduction‐associated subsurface cross‐shelfbreak transport of the shelf water could be substantial relative to other major forms of shelfbreak water exchange. This study also proposes that outward spreading of the ring‐edge front by the frontal subduction may facilitate entrainment of the shelf water by the ring‐edge current and enhances the shelf‐water streamer transport at the shelf edge.W. G. Z. was supported by the National Science Foundation under grants OCE‐1657853, OCE‐1657803, and OCE 1634965. JP is grateful for the support of the Woods Hole Oceanographic Institution Summer Student Fellow Program in 2016 and 2017. W. G. Z. thanks Kenneth Brink, Glen Gawarkiewicz, Rocky Geyer, Steven Lentz, Dennis McGillicuddy, Robert Todd, and John Trowbridge for helpful discussions during the course of the study or useful comments on earlier versions of the manuscript. The satellite sea surface temperature data were obtained from the University of Delaware Ocean Exploration, Remote Sensing, Biogeography Lab (led by Matthew Oliver), through the Mid‐Atlantic Coastal Ocean Observing System (MARACOOS) data server (http://tds.maracoos.org/thredds/catalog.html). The OOI Pioneer Array mooring and glider data presented in this paper were downloaded from the National Science Foundation OOI data portal (http://ooinet.oceanobservatories.org) in July–August 2016.2019-04-1

Een archeologische evaluatie en waardering van het slagveld van Oudenaarde 1708 (Oudenaarde, provincie Oost-Vlaanderen)

Het Ename Expertisecentrum voor Erfgoedontsluiting (EEC) heeft in 2011 en 2012 in opdracht van het agentschap Onroerend Erfgoed en in functie van de mogelijke opmaak van een beschermingsdossier een archeologische evaluatie en waardering uitgevoerd van het slagveld van Oudenaarde 1708. Een eerdere survey uit 2007 onder leiding van de Britse Battlefields Trust had via metaaldetectie het archeologisch potentieel van dit slagveld aangetoond en een doorgedreven onderzoek van het slagveld mogelijk en wenselijk gemaakt. Het veldwerk werd uitgevoerd van 12 september tot 31 oktober 2011. De studie maakte een aanzienlijke vooruitgang in het begrijpen van de veldslag en in het plaatsen van de actie op het terrein, en liet toe om de aard, de toestand en de verspreiding van de archeologische zone te bepalen en de problemen die dit oplevert. Terzelfdertijd heeft dit werk inzicht gegeven in de praktische problemen op het veld, en een strategie opgeleverd voor verder onderzoek. De belangrijkste primaire bronnen van de veldslag werden samengebracht en vertaald en de grafische en geschreven bronnen werden in een redelijk accurate weergave van het landschap geplaatst zoals het er ten tijde van de veldslag moet hebben uitgezien. Oudenaarde bleek een ongewoon complexe veldslag met een opmerkelijke wisselwerking tussen het terrein en de acties. Door de goede staat van bewaring van het merendeel van het slagveld kan Oudenaarde van aanzienlijk belang zijn bij de verdere ontwikkeling van slagveldarcheologie. De kogels zijn weliswaar relatief slecht bewaard, maar toch nog voldoende goed om een adequate analyse van de inslagschade te bekomen. Het gebruik als akkerland sinds de late 18e eeuw had een ernstige destructief effect op slagveldartefacten. Het losmaken van de grond en diep ploegen is wellicht ook zeer destructief voor eventuele massagraven. Het permanent grasland op een beperkt deel van het terrein tempert wel de snelheid van verval van de artefacten, aangezien zowel verluchting van de grond als mechanische schade hierdoor vermeden wordt. De studie eindigt met aanbevelingen over de mogelijke begrenzing van de archeologische zone en stelt ook maatregelen voor naar beheer en behoud van de site

Characterization of Burkholderia rhizoxinica and B. endofungorum Isolated from Clinical Specimens

Eight isolates submitted to CDC from 1989 to 2006 from clinical specimens were initially identified as members of the genus Burkholderia based on preliminary cellular fatty acid analysis and/or 16S rRNA gene sequencing. With the recent descriptions of the new species B. rhizoxinica and B. endofungorum, which are considered endosymbiotic bacteria in Rhizopus microsporus fungi, we now identify seven of these clinical isolates as B. rhizoxinica and one as B. endofungorum based on biochemical testing, 16s rRNA, and DNA-DNA hybridization results. We also further characterize these isolates by assessing toxin production and/or by multiple locus sequence typing

Autologous whole ram seminal plasma and its vesicle-free fraction improve motility characteristics and membrane status but not in vivo fertility of frozen-thawed ram spermatozoa

Motility characteristics (assessed subjectively and with computer-assisted semen analysis) and membrane status (after staining with chlortetracycline) of washed and non-washed frozen-thawed ram spermatozoa were evaluated after incubation in buffer and buffer containing autologous whole seminal plasma or one of its two fractions: the pellet of membrane vesicles obtained by ultracentrifugation (and used at three times normal protein concentration) or the vesicle-free supernatant fraction. Whole seminal plasma and supernatant, but not membrane vesicles, improved the motility characteristics of spermatozoa after 3 and 6 h of post-thaw incubation compared with the control buffer. Resuspension and incubation with whole seminal plasma, supernatant or membrane vesicles lowered the proportion of acrosome-reacted frozen-thawed spermatozoa compared with the control buffer. Unwashed frozen-thawed semen from three rams, incubated with autologous whole seminal plasma or its fractions and inseminated using cervical or intrauterine artificial insemination, had no effect on pregnancy rates of ewes in synchronized oestrus. However, fertility was higher after laparoscopic than cervical insemination (44.9 vs 12.3%, p < 0.001). In conclusion, resuspension and incubation of frozen-thawed ram spermatozoa in autologous whole seminal plasma or its vesicle-free supernatant fraction improved their motility characteristics and, with membrane vesicles, membrane status, but these benefits were not reflected in improved fertility after cervical or intrauterine insemination. © 2007 The Authors

The changing nature of shelf-break exchange revealed by the OOI Pioneer Array

Author Posting. © The Oceanography Society, 2018. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 31, no. 1 (2018): 60–70, doi:10.5670/oceanog.2018.110.Although the continental shelf and slope south of New England have been the subject of recent studies that address decadal-scale warming and interannual variability of water mass properties, it is not well understood how these changes affect shelf-break exchange processes. In recent years, observations of anomalous shelf and slope conditions obtained from the Ocean Observatories Initiative Pioneer Array and other regional observing programs suggest that onshore intrusions of warm, salty waters are becoming more prevalent. Mean cross-shelf transects constructed from Pioneer Array glider observations collected from April 2014 through December 2016 indicate that slope waters have been warmer and saltier. We examine shelf-break exchange events and anomalous onshore intrusions of warm, salty water associated with warm core rings located near the shelf break in spring 2014 and winter 2017 using observations from the Pioneer Array and other sources. We also describe an additional cross-shelf intrusion of ring water in September 2014 to demonstrate that the occurrence of high-salinity waters extending across the continental shelf is rare. Observations from the Pioneer Array and other sources show warm core ring and Gulf Stream water masses intrude onto the continental shelf more frequently and penetrate further onshore than in previous decades.GG, WZ, RT, and MD were supported by the National Science Foundation under grant OCE-1657853. WZ was also supported by grant OCE-1634965. JP is grateful for the support of the Woods Hole Oceanographic Institution Summer Student Fellow Program. AMM was supported by a grant from the MacArthur Foundation. GG and AMM were also supported by a grant from the van Beuren Charitable Foundation for collection and analysis of hydrographic data collected by the CFRF Shelf Research Fleet

Involvement of loops 2 and 3 of alpha-sarcin on its ribotoxic activity

Ribotoxins are a family of fungal ribosome-inactivating proteins displaying highly specific ribonucleolytic activity against the sarcin/ricin loop (SRL) of the larger rRNA, with a-sarcin as its best-characterized member. Their toxicity arises from the combination of this activity with their ability to cross cell membranes. The involvement of a-sarcin's loops 2 and 3 in SRL and ribosomal proteins recognition, as well as in the ribotoxin-lipid interactions involving cell penetration, has been suggested some time ago. In the work presented now different mutants have been prepared in order to study the role of these loops in their ribonucleolytic and lipid-interacting properties. The results obtained confirm that loop 3 residues Lys 111, 112, and 114 are key actors of the specific recognition of the SRL. In addition, it is also shown that Lys 114 and Tyr 48 conform a network of interactions which is essential for the catalysis. Lipid-interaction studies show that this Lys-rich region is indeed involved in the phospholipids recognition needed to cross cell membranes. Loop 2 is shown to be responsible for the conformational change which exposes the region establishing hydrophobic interactions with the membrane inner leaflets and eases penetration of ribotoxins target cells

CD38 Exacerbates Focal Cytokine Production, Postischemic Inflammation and Brain Injury after Focal Cerebral Ischemia

BACKGROUND: Converging evidence suggests that inflammatory processes significantly influence brain injury and clinical impairment in ischemic stroke. Although early studies suggested a key role of lymphocytes, recent data has emphasized the orchestrating function of innate immunity, i.e., macrophages and microglia. The bifunctional receptor and ectoenzyme CD38 synthesizes calcium-mobilizing second messengers (e.g., cyclic ADP-ribose), which have been shown to be necessary for activation and migration of myeloid immune cells. Therefore, we investigated the dynamics of CD38 in stroke and the impact of CD38-deficiency on cytokine production, inflammation and cerebral damage in a mouse model of cerebral ischemia-reperfusion. METHODOLOGY/PRINCIPAL FINDINGS: We show that the local expression of the chemokine MCP-1 was attenuated in CD38-deficient mice compared with wildtype mice after focal cerebral ischemia and reperfusion. In contrast, no significant induction of MCP-1 expression was observed in peripheral blood after 6 hours. Flow cytometry analysis revealed less infiltrating macrophages and lymphocytes in the ischemic hemisphere of CD38-deficient mice, whereas the amount of resident microglia was unaltered. An up-regulation of CD38 expression was observed in macrophages and CD8(+) cells after focal cerebral ischemia in wildtype mice, whereas CD38 expression was unchanged in microglia. Finally, we demonstrate that CD38-deficiency decreases the cerebral ischemic injury and the persistent neurological deficit after three days of reperfusion in this murine temporary middle cerebral artery occlusion (tMCAO) model. CONCLUSION/SIGNIFICANCE: CD38 is differentially regulated following stroke and its deficiency attenuates the postischemic chemokine production, the immune cell infiltration and the cerebral injury after temporary ischemia and reperfusion. Therefore CD38 might prove a therapeutic target in ischemic stroke

Failure patterns of solder joints identified through lifetime vibration tests

A method for non-destructively tracking the integrity of flip chip solder joints through life is investigated in this paper. An industry standard double-sided PCB was designed and manufactured with 14 flip chips to assess the failure patterns of each flip chip and each solder joint in lifetime vibration tests. Two configurations of PCB finish were tested, Electro Nickel Immersion Gold (ENIG) and Hot Air Surface Levelled lead (Pb HASL) using automotive industry manufacturing processes and quality standards. A random vibration test over a frequency range 10 Hz to 1000 Hz was specified by automotive engineers to replicate vibrations typically found on road vehicles. This vibration profile was applied to test circuit board assemblies (CBA) for 4-minute intervals until failure of all chips. At each interval test boards were extensively scanned by an acoustic micro-imaging (AMI) microscope to non-destructively measure parameters of solder joints. This enabled tracking of mechanical joint connection through-life. Methods were developed to process the large number of acoustic images of each solder joint and form metrics to evaluate solder joint integrity. Results from AMI show that the solder joints exhibit three distinct zones as they age: crack initiation, crack propagation and then failure

Evolution of an endofungal Lifestyle: Deductions from the Burkholderia rhizoxinica Genome

<p>Abstract</p> <p>Background</p> <p><it>Burkholderia rhizoxinica </it>is an intracellular symbiont of the phytopathogenic zygomycete <it>Rhizopus microsporus</it>, the causative agent of rice seedling blight. The endosymbiont produces the antimitotic macrolide rhizoxin for its host. It is vertically transmitted within vegetative spores and is essential for spore formation of the fungus. To shed light on the evolution and genetic potential of this model organism, we analysed the whole genome of <it>B. rhizoxinica </it>HKI 0454 - a type strain of endofungal <it>Burkholderia </it>species.</p> <p>Results</p> <p>The genome consists of a structurally conserved chromosome and two plasmids. Compared to free-living <it>Burkholderia </it>species, the genome is smaller in size and harbors less transcriptional regulator genes. Instead, we observed accumulation of transposons over the genome. Prediction of primary metabolic pathways and transporters suggests that endosymbionts consume host metabolites like citrate, but might deliver some amino acids and cofactors to the host. The rhizoxin biosynthesis gene cluster shows evolutionary traces of horizontal gene transfer. Furthermore, we analysed gene clusters coding for nonribosomal peptide synthetases (NRPS). Notably, <it>B. rhizoxinica </it>lacks common genes which are dedicated to quorum sensing systems, but is equipped with a large number of virulence-related factors and putative type III effectors.</p> <p>Conclusions</p> <p><it>B. rhizoxinica </it>is the first endofungal bacterium, whose genome has been sequenced. Here, we present models of evolution, metabolism and tools for host-symbiont interaction of the endofungal bacterium deduced from whole genome analyses. Genome size and structure suggest that <it>B. rhizoxinica </it>is in an early phase of adaptation to the intracellular lifestyle (genome in transition). By analysis of tranporters and metabolic pathways we predict how metabolites might be exchanged between the symbiont and its host. Gene clusters for biosynthesis of secondary metabolites represent novel targets for genomic mining of cryptic natural products. <it>In silico </it>analyses of virulence-associated genes, secreted proteins and effectors might inspire future studies on molecular mechanisms underlying bacterial-fungal interaction.</p