2,679 research outputs found
Spatial and temporal evolution of the Le Danois Contourite Depositional System, Southern Bay of Biscay
Differences in smokers’ awareness of the health risks of smoking before and after introducing pictorial tobacco health warnings: findings from the 2012–2017 international tobacco control (ITC) Netherlands surveys
Did e-cigarette users notice the new European Union’s e-cigarette legislation? Findings from the 2015-2017 International Tobacco Control (ITC) Netherlands Survey
Did e-cigarette users notice the new European Union’s e-cigarette legislation? Findings from the 2015-2017 International Tobacco Control (ITC) Netherlands Survey
A multi-gene phylogeny of Lactifluus (Basidiomycota, Russulales) translated into a new infrageneric classification of the genus
Infrageneric relations of the genetically diverse milkcap genus Lactifluus (Russulales, Basidiomycota) are poorly known. Currently used classification systems still largely reflect the traditional, mainly morphological, characters used for infrageneric delimitations of milkcaps. Increased sampling, combined with small-scale molecular studies, show that this genus is underexplored and in need of revision. For this study, we assembled an extensive dataset of the genus Lactifluus, comprising 80 % of all known species and 30 % of the type collections. To unravel the infrageneric relationships within this genus, we combined a multi-gene molecular phylogeny, based on nuclear ITS, LSU, RPB2 and RPB1, with a morphological study, focussing on five important characteristics (fruit body type, presence of a secondary velum, colour reaction of the latex/context, pileipellis type and presence of true cystidia). Lactifluus comprises four supported subgenera, each containing several supported clades. With extensive sampling, ten new clades and at least 17 new species were discovered, which highlight the high diversity in this genus. The traditional infrageneric classification is only partly maintained and nomenclatural changes are proposed. Our morphological study shows that the five featured characteristics are important at different evolutionary levels, but further characteristics need to be studied to find morphological support for each clade. This study paves the way for a more detailed investigation of biogeographical history and character evolution within Lactifluus
Far-ultraviolet Dust Extinction and Molecular Hydrogen in the Diffuse Milky Way Interstellar Medium
We aim to compare variations in the full-UV dust extinction curve (912-3000
Angstrom), with the HI/H/total H content along diffuse Milky Way
sightlines, to investigate possible connections between ISM conditions and dust
properties. We combine an existing sample of 75 UV extinction curves based on
IUE and FUSE data, with atomic and molecular column densities measured through
UV absorption. The H column density data are based on existing Lyman-Werner
absorption band models from earlier work on the extinction curves. Literature
values for the HI column density were compiled, and improved for 23 stars by
fitting a Ly profile to archived spectra. We discover a strong
correlation between the H column and the far-UV extinction, and the
underlying cause is a linear relationship between H and the strength of the
far-UV rise feature. This extinction does not scale with HI, and the total H
column scales best with instead. The carrier of the far-UV rise
therefore coincides with molecular gas, and further connections are shown by
comparing the UV extinction features to the molecular fraction. Variations in
the gas-to-extinction ratio correlate with the UV-to-optical
extinction ratio, and we speculate this could be due to coagulation or
shattering effects. Based on the H temperature, the strongest far-UV rise
strengths are found to appear in colder and denser sightlines.Comment: 24 pages, 9 figures, accepted for publication in ApJ; fix missing
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How the new European Union’s (pictorial) tobacco health warnings influence quit attempts and smoking cessation: Findings from the 2016-2017 International Tobacco Control (ITC) Netherlands Surveys
How the new European Union’s (pictorial) tobacco health warnings influence quit attempts and smoking cessation: Findings from the 2016-2017 International Tobacco Control (ITC) Netherlands Surveys
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