1,502 research outputs found
An expanded multilocus sequence typing scheme for propionibacterium acnes : investigation of 'pathogenic', 'commensal' and antibiotic resistant strains
The Gram-positive bacterium Propionibacterium acnes is a member of the normal human skin microbiota and is associated with various infections and clinical conditions. There is tentative evidence to suggest that certain lineages may be associated with disease and others with health. We recently described a multilocus sequence typing scheme (MLST) for P. acnes based on seven housekeeping genes (http://pubmlst.org/pacnes). We now describe an expanded eight gene version based on six housekeeping genes and two âputative virulenceâ genes (eMLST) that provides improved high resolution typing (91eSTs from 285 isolates), and generates phylogenies congruent with those based on whole genome analysis. When compared with the nine gene MLST scheme developed at the University of Bath, UK, and utilised by researchers at Aarhus University, Denmark, the eMLST method offers greater resolution. Using the scheme, we examined 208 isolates from disparate clinical sources, and 77 isolates from healthy skin. Acne was predominately associated with type IA1 clonal complexes CC1, CC3 and CC4; with eST1 and eST3 lineages being highly represented. In contrast, type IA2 strains were recovered at a rate similar to type IB and II organisms. Ophthalmic infections were predominately associated with type IA1 and IA2 strains, while type IB and II were more frequently recovered from soft tissue and retrieved medical devices. Strains with rRNA mutations conferring resistance to antibiotics used in acne treatment were dominated by eST3, with some evidence for intercontinental spread. In contrast, despite its high association with acne, only a small number of resistant CC1 eSTs were identified. A number of eSTs were only recovered from healthy skin, particularly eSTs representing CC72 (type II) and CC77 (type III). Collectively our data lends support to the view that pathogenic versus truly commensal lineages of P. acnes may exist. This is likely to have important therapeutic and diagnostic implications
Hydrogen Motion in Magnesium Hydride by NMR
In coarse-grained MgH2, the diffusive motion of hydrogen remains too slow (<10^5 hops s^â1) to narrow the H NMR line up to 400 °C. Slow-motion dipolar relaxation time T1D measurements reveal the motion, with hopping rate ĎH from 0.1 to 430 s^â1 over the range of 260 to 400 °C, the first direct measurement of H hopping in MgH2. The ĎH data are described by an activation energy of 1.72 eV (166 kJ/mol) and attempt frequency of 2.5 Ă 10^15 s^â1. In ball-milled MgH2 with 0.5 mol % added Nb2O5 catalyst, line-narrowing is evident already at 50 °C. The line shape shows distinct broad and narrow components corresponding to immobile and mobile H, respectively. The fraction of mobile H grows continuously with temperature, reaching âź30% at 400 °C. This demonstrates that this materialâs superior reaction kinetics are due to an increased rate of H motion, in addition to the shorter diffusion paths from ball-milling. In ball-milled MgH2 without additives, the line-narrowed component is weaker and is due, at least in part, to trapped H2 gas. The spinâlattice relaxation rates T1^â1 of all materials are compared, with ball-milling markedly increasing T1^â1. The weak temperature dependence of T1^â1 suggests a mechanism with paramagnetic relaxation centers arising from the mechanical milling
Wetland and Hydric Soils
Soil and the inherent biogeochemical processes in wetlands contrast starkly with those in upland forests and rangelands. The differences stem from extended periods of anoxia, or the lack of oxygen in the soil, that characterize wetland soils; in contrast, upland soils are nearly always oxic. As a result, wetland soil biogeochemistry is characterized by anaerobic processes, and wetland vegetation exhibits specific adaptations to grow under these conditions. However, many wetlands may also have periods during the year where the soils are unsaturated and aerated. This fluctuation between aerated and nonaerated soil conditions, along with the specialized vegetation, gives rise to a wide variety of highly valued ecosystem services
Winners and losers: Emotional shifts across elections are conveyed by a politicianâs smile
The human smile can convey both rewarding and affiliative social intent and thus has significant utility in politics, where the ability to bond with and reassure voters is vital to electoral success. We examine experimental evidence from the 2019 UK general election to investigate the influence of a politicianâs reward or affiliative smile on voter emotions. It was hypothesised that the winnerâs affiliative smile would engender positive affect across all partisan groups compared to the winnerâs reward smile display. Participants from a nationally representative sample were shown campaign footage containing both types of smiles from the leaders of the main competing political parties both before and after the election. Increases in happiness and affinity were revealed across all partisan groups when shown footage of the eventual winnerâs affiliative smile; at the same time, supporters of losing parties indicated a decrease in negative affect. Affinity has been shown to increase civic engagement. Thus, we conclude that affiliative smiles displayed by leading candidates during the campaign likely acted as a mechanism to align voter behaviour with the dominant political message
Bimodality and alternative equilibria do not help explain long-term patterns in shallow lake chlorophyll-a
Since its inception, the theory of alternative equilibria in shallow lakes has
evolved and been applied to an ever wider range of ecological and socioecological
systems. The theory posits the existence of two alternative stable
states or equilibria, which in shallow lakes are characterised by either clear
water with abundant plants or turbid water where phytoplankton dominate.
Here, we used data simulations and real-world data sets from Denmark and
north-eastern USA (902 lakes in total) to examine the relationship between
shallow lake phytoplankton biomass (chlorophyll-a) and nutrient concentrations
across a range of timescales. The data simulations demonstrated that
three diagnostic tests could reliably identify the presence or absence of
alternative equilibria. The real-world data accorded with data simulations
where alternative equilibria were absent. Crucially, it was only as the temporal
scale of observation increased (>3 years) that a predictable linear relationship
between nutrient concentration and chlorophyll-a was evident. Thus, when a
longer term perspective is taken, the notion of alternative equilibria is not
required to explain the response of chlorophyll-a to nutrient enrichment
which questions the utility of the theory for explaining shallow lake response
to, and recovery from, eutrophication.C.D.S. and T.A.D. would like to thank June and Derek Sayer for extraordinary
support over many years. The authors of this work have been
supported by a number of projects over the elephantine gestation period
of this manuscript. These include support from the Poul Due Jensen
Fonden, Danmarks Frie Forskningsfond Natur og Univers project
GREENLAKES (No. 9040-00195B) and the UFM-funded project LTER_DK
for Long Term Ecosystem Research in Denmark. In addition, support was
provided by The European Unionâs Horizon 2020 research and innovation
programmes under grant agreement No 869296âThe PONDERFUL
Projectâ, TREICLAKE under grant agreement No 951963, and the
AQUACOSM project and by the European Commission EU H2020-
INFRAIA-project (No. 731065) and AQUACOSMplus (No. 871081). E.J. was
also supported by the TĂBITAK outstanding researcher programme2232
(project 118C250) and AnaEE, Denmark. The work of D.G. was funded by
the Fourth Period of Programme-oriented Funding, Helmholtz Association
of German ResearchCentres, Research Field Earth and Environment.C.D.S. and T.A.D. would like to thank June and Derek Sayer for extraordinary
support over many years. The authors of this work have been
supported by a number of projects over the elephantine gestation period
of this manuscript. These include support from the Poul Due Jensen
Fonden, Danmarks Frie Forskningsfond Natur og Univers project
GREENLAKES (No. 9040-00195B) and the UFM-funded project LTER_DK
for Long Term Ecosystem Research in Denmark. In addition, support was
provided by The European Unionâs Horizon 2020 research and innovation
programmes under grant agreement No 869296âThe PONDERFUL
Projectâ, TREICLAKE under grant agreement No 951963, and the
AQUACOSM project and by the European Commission EU H2020-
INFRAIA-project (No. 731065) and AQUACOSMplus (No. 871081). E.J. was
also supported by the TĂBITAK outstanding researcher programme2232
(project 118C250) and AnaEE, Denmark. The work of D.G. was funded by
the Fourth Period of Programme-oriented Funding, Helmholtz Association
of German ResearchCentres, Research Field Earth and Environment
Emotional response to U.K. political party leader facial displays of affiliation, reward, and ambiguity during Brexit
Objective: On December 12, 2019, the United Kingdom's ruling Conservative Party called an election that put the country's 2016 âBrexitâ referendum on leaving the European Union to the test. The divisive campaign and a polarized electorate culminated in large losses by opposition Labour and Liberal Democratic parties. Amid a polarized electorate, lingering questions arise as to whether the election results reflect more upon partisan ties or the respective party leaders' ability to emotionally connect with followers through their nonverbal behavior. Methods: Using a unique preâregistered design, this study considers the emotional response to leaders of the three major U.K. political parties in the week prior to the December 2019 election by drawing upon a national sample of 546 partisan participants. We examine selfâreported happiness, affinity, anger, and distress in response to reward and affiliative smiles as well as ambiguous facial displays in short videos shown without sound featuring Conservative Party leader Boris Johnson and his opponents Jeremy Corbyn (Labour Party) and Jo Swinson (Liberal Democratic Party). Results: The findings of this preâregistered study suggests partisan identity plays a powerful role in empathetic and counterâempathetic responses to leader facial displays generally. Further analysis reveals a more nuanced response to the competing leadersâ facial displays with followers of all three parties responding to the different smiles in distinct manners
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