713 research outputs found
Characterization of acoustic emission signals under 3-point bending test
This paper summarizes a master’s thesis project which explored whether the characteristics of Acoustic Emission Testing (AET) signals can be used to detect yielding in steel samples undergoing a three-point bending test. A subset of existing data from a three-point bending test was exported and used as input. Data was processed by utilizing and developing tools to visualize and analyse the signal characteristics, primarily through a parameter-based approach. Signals were visualized, and parameters were optimized to identify and classify signal types. According to the obtained results, some limitations on classification were experienced due to the length of the hit data recorded. Though the work reported in this article lead to a reliable method for detecting yielding, the developed algorithms were not successful in identifying characteristics that could be used to detect yielding.publishedVersio
Calicivirus VP2 forms a portal-like assembly following receptor engagement
To initiate infection, many viruses enter their host cells by triggering endocytosis following receptor engagement. However, the mechanisms by which non-enveloped viruses escape the endosome are poorly understood. Here we present near-atomic-resolution cryo-electron microscopy structures for feline calicivirus both undecorated and labelled with a soluble fragment of its cellular receptor, feline junctional adhesion molecule A. We show that VP2, a minor capsid protein encoded by all caliciviruses1,2, forms a large portal-like assembly at a unique three-fold axis of symmetry, following receptor engagement. This assembly—which was not detected in undecorated virions—is formed of twelve copies of VP2, arranged with their hydrophobic N termini pointing away from the virion surface. Local rearrangement at the portal site leads to the opening of a pore in the capsid shell. We hypothesize that the portal-like assembly functions as a channel for the delivery of the calicivirus genome, through the endosomal membrane, into the cytoplasm of a host cell, thereby initiating infection. VP2 was previously known to be critical for the production of infectious virus3; our findings provide insights into its structure and function that advance our understanding of the Caliciviridae
Vannkvalitet og anadrom fisk i Høyanger- og Ortneviksvassdraget i Sogn og Fjordane
På oppdrag fra Fylkemannens miljøvernavdeling i Sogn og Fjordane har en undersøkt vannkvalitet, anadrom fisk og bunndyr i Ortneviksvassdraget og Høyangervassdraget (Daleelva). Målet for undersøkelsen, som ble gjennomført i september/oktober 1997, var å vurdere om forsuring er et problem for fisken i vassdragene, samt klarlegge effektene av regulering. Begge vassdagene er påvirket av sur nedbør, og prøvene viste små vannkjemiske forskjeller mellom dem. pH lå i området 5,7-6,0 i Ortneviksvassdraget, og 5,9-6,0 i Daleelva. Konsentrasjonen av labilt aluminium var opp mot 10 µg/L i begge vassdragene. pH er høyere og konsentrasjonen av labilt aluminium er lavere enn det som ble funnet ved prøvetakingen i vassdragene våren 1997. Fiskeundersøkelsen viste at Ortneviksvassdraget har en selvreproduserende og livskraftig bestand av aure. Det ble ikke fanget laks i vassdraget, og dette tyder på at laksebestanden pr.i dag enten er gått tapt eller er tilstede som en marginal restbestand. Dette har trolig sammenheng med den sure vannkvaliteten, og ANC verdiene i vårprøvene ligger i en område hvor en kan vente at laksebestanden er dødd ut. Høyangervassdraget har en selvproduserende bestand av laks, men tetthetene er lave. Aurebestanden derimot er livskraftig, med gjennomgående høye tettheter av ungfisk. Vannkvaliteten med lave ANC verdier og høye AL konsentrasjoner om våren kan bidra til å forklare de lave tetthetene av laks. Høyangervassdraget er i tillegg sterkt reguelert. Effektene av den omfattende reguleringen av vassdraget kan vanskelig tallfestes på bestandsnivå, men det er sannsynlig at den har medført en betydelig reduksjon av produksjonspotensialet for anadrom fisk
Biomagnification of Polybrominated Diphenyl Ether and Hexabromocyclododecane flame retardants in the Polar Bear food chain in Svalbard, Norway
Calicivirus VP2 forms a portal-like assembly following receptor engagement.
To initiate infection, many viruses enter their host cells by triggering endocytosis following receptor engagement. However, the mechanisms by which non-enveloped viruses escape the endosome are poorly understood. Here we present near-atomic-resolution cryo-electron microscopy structures for feline calicivirus both undecorated and labelled with a soluble fragment of its cellular receptor, feline junctional adhesion molecule A. We show that VP2, a minor capsid protein encoded by all caliciviruses1,2, forms a large portal-like assembly at a unique three-fold axis of symmetry, following receptor engagement. This assembly-which was not detected in undecorated virions-is formed of twelve copies of VP2, arranged with their hydrophobic N termini pointing away from the virion surface. Local rearrangement at the portal site leads to the opening of a pore in the capsid shell. We hypothesize that the portal-like assembly functions as a channel for the delivery of the calicivirus genome, through the endosomal membrane, into the cytoplasm of a host cell, thereby initiating infection. VP2 was previously known to be critical for the production of infectious virus3; our findings provide insights into its structure and function that advance our understanding of the Caliciviridae.IG is a Wellcome Senior Fellow (Ref: 207498/Z/17/Z). M.J.C. was supported by a PhD studentship from the UK Biotechnology and Biological Sciences Research Council (BBSRC WestBIO DTP: BB/J013854/1). D.B and M.M. are supported by the UK Medical Research Council (MC_UU_12014/7)
Monitoring Chemical Pollution in Europe’s Seas: Programmes, practices and priorities for research
This report has been produced by the Marine Board Working Group on Existing and Emerging Chemical Pollutants (WGPOL) first convened in 2008 and tasked to examine the assessment and monitoring of existing and emerging chemicals in the European marine and coastal environment. The Working Group considered (i) existing monitoring/assessment frameworks; (ii) current monitoring practices; and (iii) new and emerging chemicals of concern and the mechanisms used to include them in current monitoring programmes. The primary conclusions and recommendations of this position paper are:
1. Fully implement state of the art environmental risk assessment procedures (combining exposure and effect assessment) to evaluate the full impact of chemical substances on the different compartments of coastal and open sea systems.
2. Further improve the coordination, cooperation and harmonization between existing monitoring efforts and those under development, to avoid duplication of effort, loss of expertise and a reduced willingness to fulfil the obligations towards regional conventions.
3. Ensure that the development and implementation of monitoring programmes for the assessment of chemicals in marine and coastal environment are based on a science-based and dynamic process.
4. Apply more resources targeted at developing appropriate approaches, tools and practices (education and training) to improve the acquisition and management of monitoring data.
In addition to the above main recommendations, two further recommendations have been identified on the basis of two specific case studies which form part of this paper and which focus on the release, effects and monitoring of (i) hydrophobic and insoluble chemicals in the marine environment from merchant shipping; and (ii) chemicals released by the offshore oil-industry in the North Sea. These case studies highlighted the need to:
5. Develop a consistent, pan-European or regional (legal) framework/regulation which covers the activities of the oil and gas industry at sea. At the same time, more information and research is needed on the release and the effects of chemicals arising from offshore oil and gas activities.
6. Develop and apply state-of-the-art environmental risk assessment procedures (combining exposure and effect assessments, including on human health) to evaluate the impact of noxious liquid substances listed under MARPOL Annex II on the different compartments in coastal and open sea ecosystems
A Comparison of the Wholesale Model and the Agency Model in Differentiated Markets
We compare the wholesale model and the agency model that characterise a vertical relation in a bilateral duopoly framework. Results suggest that the agency model may be regarded as an example of retailer power resale price maintenance and provide an economic view of why restraints of this kind should be evaluated under the rule of reason. While competition is more likely to be undercut under the agency model, relative to the wholesale model, the agency model benefits consumers by offering relatively lower retail prices and greater demand
Gytefeltskartlegging Nordøstarktisk hyse: Toktnummer 2022609
Gytekartleggingstokt for nordøstarktisk hyse ble gjennomført 8. -19. april 2022 med FF Kristine Bonnevie. Toktet startet i Bodø og ble avsluttet i Tromsø. Toktet dekket det antatte gyteområdet langs Eggakanten mellom Malangsgrunnen og Bjørnøyrenna. Kontinuerlige akustiske registringer ble gjort langs 3194 nautiske mil kurslinjer. Det ble tatt 38 stasjoner med egghåv og CTD, og 29 bunntrål. Gytende hyse ble funnet i de fleste trålhalene. De innsamlete eggene er sendt til genetisk analyse for å kunne skille torsk- og hyseegg.publishedVersio
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