1,065 research outputs found

    Uncertainties in projecting climate-change impacts in marine ecosystems

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    Projections of the impacts of climate change on marine ecosystems are a key prerequisite for the planning of adaptation strategies, yet theyare inevitablyassociated withuncertainty.Identifying,quantifying,andcommunicatingthisuncertaintyis keytobothevaluatingtherisk associated with a projection and building confidence in its robustness. Wereview howuncertainties in such projections are handled in marine science. We employan approach developedin climatemodelling by breaking uncertainty down into(i) structural (model) uncertainty,(ii) initialization and internalvariabilityuncertainty,(iii)parametricuncertainty,and(iv)scenariouncertainty.Foreachuncertaintytype,wethenexaminethecurrent state-of-the-art in assessing and quantifying its relative importance. We consider whether the marine scientific community has addressed these types of uncertainty sufficiently and highlight the opportunities and challenges associated with doing a better job. We find that even within a relatively small field such as marine science, there are substantial differences between subdisciplines in the degree of attention given to each type of uncertainty. We find that initialization uncertainty is rarely treated explicitly and reducing this type of uncertainty may deliver gainsontheseasonal-to-decadaltime-scale.Weconcludethatallpartsofmarinesciencecouldbenefitfromagreaterexchangeofideas,particularly concerningsuchauniversalproblemsuchasthetreatmentofuncertainty.Finally,marinescienceshouldstrivetoreachthepointwherescenario uncertainty is the dominant uncertainty in our projections

    Surface Plasmon Resonance from Bimetallic Interface in Au–Ag Core–Shell Structure Nanowires

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    Transverse surface plasmon resonances (SPR) in Au–Ag and Ag–Au core–shell structure nanowires have been investigated by means of quasi-static theory. There are two kinds of SPR bands resulting from the outer surface of wall metal and the interface between core and wall metals, respectively. The SPR corresponding to the interface, which is similar to that of alloy particle, decreases and shifts obviously with increasing the wall thickness. However, the SPR corresponding to the outer surface, which is similar to that of pure metal particle, increases and shifts slightly with increasing the wall thickness. A mechanism based on oscillatory surface electrons under coulombic attraction is developed to illuminate the shift fashion of SPR from bimetallic core–shell interface. The net charges and extra coulombic force in metallic wall affect the SPR energy and the shift fashion

    An Anti-Glitch in a Magnetar

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    Magnetars are neutron stars showing dramatic X-ray and soft γ\gamma-ray outbursting behaviour that is thought to be powered by intense internal magnetic fields. Like conventional young neutron stars in the form of radio pulsars, magnetars exhibit "glitches" during which angular momentum is believed to be transferred between the solid outer crust and the superfluid component of the inner crust. Hitherto, the several hundred observed glitches in radio pulsars and magnetars have involved a sudden spin-up of the star, due presumably to the interior superfluid rotating faster than the crust. Here we report on X-ray timing observations of the magnetar 1E 2259+586 which we show exhibited a clear "anti-glitch" -- a sudden spin down. We show that this event, like some previous magnetar spin-up glitches, was accompanied by multiple X-ray radiative changes and a significant spin-down rate change. This event, if of origin internal to the star, is unpredicted in models of neutron star spin-down and is suggestive of differential rotation in the neutron star, further supporting the need for a rethinking of glitch theory for all neutron stars

    On the selection and design of proteins and peptide derivatives for the production of photoluminescent, red-emitting gold quantum clusters

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    Novel pathways of the synthesis of photoluminescent gold quantum clusters (AuQCs) using biomolecules as reactants provide biocompatible products for biological imaging techniques. In order to rationalize the rules for the preparation of red-emitting AuQCs in aqueous phase using proteins or peptides, the role of different organic structural units was investigated. Three systems were studied: proteins, peptides, and amino acid mixtures, respectively. We have found that cysteine and tyrosine are indispensable residues. The SH/S-S ratio in a single molecule is not a critical factor in the synthesis, but on the other hand, the stoichiometry of cysteine residues and the gold precursor is crucial. These observations indicate the importance of proper chemical behavior of all species in a wide size range extending from the atomic distances (in the AuI-S semi ring) to nanometer distances covering the larger sizes of proteins assuring the hierarchical structure of the whole self-assembled system

    Bio-nanotechnology application in wastewater treatment

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    The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed

    Geographical distribution of publications in the field of medical education

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    BACKGROUND: The geographical distribution of publications as an indicator of the research productivity of individual countries, regions or institutions has become a field of interest. We investigated the geographical distribution of contributions to the two leading journals in the field of medical education, Academic Medicine and Medical Education. METHODS: PubMed was used to search Medline. For both journals all journal articles in each year from 1995 to 2000 were included into the study. Then the affiliation was retrieved from the affiliation field of the MEDLINE format. If this was not possible, it was obtained from the paper version of the journal. RESULTS: Academic Medicine published contributions from 25 countries between 1995 and 2000. Authors from 50 countries contributed to Medical Education in the same period of time. Authors from the USA and Canada wrote ca. 95% off all articles in Academic Medicine, whereas authors from the UK, Australia, the USA, Canada and the Netherlands were responsible for ca. 74% of all articles in Medical Education in the investigated period of time. CONCLUSIONS: While many countries contributed to both journals, only a few of them were responsible for the majority of all articles

    Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo

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    Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection

    Phototriggered release of tetrapeptide AAPV from coumarinyl and pyrenyl cages

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    Ala-Ala-Pro-Val (AAPV) is a bioactive tetrapeptide that inhibits human neutrophil elastase (HNE), an enzyme involved in skin chronic inflammatory diseases like psoriasis. Caged derivatives of this peptide were prepared by proper N- and C-terminal derivatisation through a carbamate or ester linkage, respectively, with two photoactive moieties, namely 7-methoxycoumarin-2-ylmethyl and pyren-2-ylmethyl groups. These groups were chosen to assess the influence of the photosensitive group and the type of linkage in the controlled photorelease of the active molecule. The caged peptides were irradiated at selected wavelengths of irradiation (254, 300, and 350 nm), and the photolytic process was monitored by HPLC-UV. The results established the applicability of the tested photoactive groups for the release of AAPV, especially for the derivative bearing the carbamate-linked pyrenylmethyl group, which displayed the shortest irradiation times for the release at the various wavelengths of irradiation (ca. 4 min at 254 nm, 8 min at 300 nm and 46 min at 350 nm).Thanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the portuguese NMR network (PTNMR, Bruker Avance III 400- Univ. Minho), FCT and FEDER (European Fund for Regional Development)- COMPETE-QREN-EU for financial support through the Chemistry Research Centre of the University of Minho (Ref. UID/QUI/00686/2013 and UID/QUI/0686/2016). A PhD grant to A.M.S. (SFRH/BD/80813/2011) is also acknowledged.info:eu-repo/semantics/publishedVersio

    Search for CP violation in D0 and D+ decays

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    A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to search for CP violation in the Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/- 0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) = +0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second error is systematic. These asymmetries are consistent with zero with smaller errors than previous measurements.Comment: 12 pages, 4 figure
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