68 research outputs found
Five-Torsion in the Homology of the Matching Complex on 14 Vertices
J. L. Andersen proved that there is 5-torsion in the bottom nonvanishing
homology group of the simplicial complex of graphs of degree at most two on
seven vertices. We use this result to demonstrate that there is 5-torsion also
in the bottom nonvanishing homology group of the matching complex on
14 vertices. Combining our observation with results due to Bouc and to
Shareshian and Wachs, we conclude that the case is exceptional; for all
other , the torsion subgroup of the bottom nonvanishing homology group has
exponent three or is zero. The possibility remains that there is other torsion
than 3-torsion in higher-degree homology groups of when and .Comment: 11 page
Annual mass budget of Antarctic ice shelves from 1997 to 2021
Antarctic ice shelves moderate the contribution of the Antarctic Ice Sheet to global sea level rise; however, ice shelf health remains poorly constrained. Here, we present the annual mass budget of all Antarctic ice shelves from 1997 to 2021. Out of 162 ice shelves, 71 lost mass, 29 gained mass, and 62 did not change mass significantly. Of the shelves that lost mass, 68 had statistically significant negative mass trends, 48 lost more than 30% of their initial mass, and basal melting was the dominant contributor to that mass loss at a majority (68%). At many ice shelves, mass losses due to basal melting or iceberg calving were significantly positively correlated with grounding line discharge anomalies; however, the strength and form of this relationship varied substantially between ice shelves. Our results illustrate the utility of partitioning high-resolution ice shelf mass balance observations into its components to quantify the contributors to ice shelf mass change and the response of grounded ice
Fitting the integrated Spectral Energy Distributions of Galaxies
Fitting the spectral energy distributions (SEDs) of galaxies is an almost
universally used technique that has matured significantly in the last decade.
Model predictions and fitting procedures have improved significantly over this
time, attempting to keep up with the vastly increased volume and quality of
available data. We review here the field of SED fitting, describing the
modelling of ultraviolet to infrared galaxy SEDs, the creation of
multiwavelength data sets, and the methods used to fit model SEDs to observed
galaxy data sets. We touch upon the achievements and challenges in the major
ingredients of SED fitting, with a special emphasis on describing the interplay
between the quality of the available data, the quality of the available models,
and the best fitting technique to use in order to obtain a realistic
measurement as well as realistic uncertainties. We conclude that SED fitting
can be used effectively to derive a range of physical properties of galaxies,
such as redshift, stellar masses, star formation rates, dust masses, and
metallicities, with care taken not to over-interpret the available data. Yet
there still exist many issues such as estimating the age of the oldest stars in
a galaxy, finer details ofdust properties and dust-star geometry, and the
influences of poorly understood, luminous stellar types and phases. The
challenge for the coming years will be to improve both the models and the
observational data sets to resolve these uncertainties. The present review will
be made available on an interactive, moderated web page (sedfitting.org), where
the community can access and change the text. The intention is to expand the
text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics &
Space Scienc
MATISSE, the VLTI mid-infrared imaging spectro-interferometer
GalaxiesStars and planetary systemsInstrumentatio
Allergic contact dermatitis caused by 1,6-hexanediol diacrylate in a hospital wristband
Background: 1,6-Hexanediol diacrylate (1,6-HDDA) is a multifunctional acrylate and a potent sensitizer. Objectives: To report a case of allergic contact dermatitis caused by 1,6-HDDA in a hospital wristband. Methods: A male patient presented with eczema on his wrist where he had worn a hospital wristband. Patch testing was performed with our extended European baseline series, additional series, and pieces of the hospital wristband. Thin-layer chromatography (TLC) was performed with extracts from the wristband and gas chromatography-mass spectrometry was used for chemical analysis. Results: Positive reactions were found to pieces of the wristband, including adhesive rim (+++), inside (+++), and outside (++); to multiple allergens in the (meth)acrylates series; and to extracts of the wristband in acetone and ethanol. Chemical analysis of the ethanol extract showed presence of lauryl acrylate and 1,6-HDDA. Patch testing with TLC strips and subsequent chemical analysis showed that the substance causing the strongest reaction was 1,6-HDDA, to which the patient had a confirmed positive patch test reaction. Conclusion: 1,6-HDDA was identified as the culprit allergen responsible for allergic contact dermatitis caused by the hospital wristband
‘Til Poison Phosphorous Brought them Death’: A potentially occupationally-related disease in a post-medieval skeleton from north-east England
This paper describes the pathological changes observed on the skeleton of a c.12–14 year old person buried in a north-east England Quaker cemetery dated to AD 1711–1857. Bone formation (woven and lamellar) and destruction are present mainly on the mandible, clavicles, sternum and scapulae, long bones of the right arm, left ribs, spine, ilia, and the femora and tibiae. Differential diagnoses of tuberculosis and other pulmonary diseases, smallpox, actinomycosis, neoplastic disease, and “phossy jaw” are considered. While the pathological changes could represent all previously described diseases and thus be associated with the insalubrious conditions in which this person lived, it is also possible that this person worked in the matchmaking industry known to be present in the region at the time. Attention is drawn to the previously overlooked condition “phossy jaw” caused by phosphorus poisoning, which was strongly associated with this industry. While matchstick making was an industry often associated with women and girls, DNA analysis of a bone sample from the skeleton did not successfully identify biological sex. Two dental calculus samples from this person were analysed for phosphorus, and comparisons were made with samples from the same and a different site; the levels did not indicate the person was more exposed to phosphorus than any of the other people at Coach Lane. However, the pathological lesions described also have relevance in a clinical context, because “phossy jaw” has been observed in living populations, arising as a consequence of ingesting phosphorous contained within some pharmaceuticals used for treating neoplastic disease and osteoporosis
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