Tracing Metonymic Relations in T-PAS: An Annotation Exercise on a Corpus-based Resource for Italian

In this paper we address the main issues and results of a research thesis (Romani, 2020) dedicated to the annotation of metonymies in T-PAS, a corpus-based digital repository of Italian verbal patterns (Ježek et al., 2014). The annotation was performed on the corpus instances of a selected list of 30 verbs and was aimed at both implementing the resource with metonymic patterns and identifying and creating a map of the metonymic relations that occur in the verbal patterns. The annotated corpus data (consisting of 1218 corpus instances), the patterns, and the relations can be useful for NLP tasks such as metonymy recognition

Multiwavelength Studies of PSR J1420-6048, a Young Pulsar in the Kookaburra

We present X-ray, radio, and infrared observations of the 68 ms pulsar PSR J1420-6048 and its surrounding nebula, a possible counterpart of the gamma-ray source GeV J1417-6100/3EG J1420-6038. Pulsed X-ray emission at the radio period is marginally detected by ASCA from a source embedded in the hard spectrum X-ray nebula AX J1420.1-6049. At radio wavelengths, the pulsar is found to be strongly linearly and circularly polarized, and the polarization sweep is measured. A comparison of high resolution ATCA radio imaging of the Kookaburra's upper wing (G313.6+0.3), which contains the pulsar and the X-ray nebula, with infrared images suggests the radio emission is partly non-thermal.Comment: 8 pages, 4 figures, to appear in Astrophysical Journal Letter

Selecting Lucerne (Medicago Sativa Complex) for Traits Conferring Adaptation to Grazing

A germplasm collection of the Medicago sativa complex was evaluated to select genotypes possessing traits possibly conferring adaptation to grazing. Deep-crowned plants, either creeping-rooted or rhizomatous, were found with different frequencies, in all “taxonomic” groups examined. Although belonging to subsp. sativa, “mielga” wild populations from Spain were closer to subsp. falcata for morpho-physiological traits. Deep-crowned plants could be categorised into four top-growth models, to which corresponded a fairly distinct underground morphology: three were rhizomatous and one creeping-rooted. Cultivars selected for creeping-rootedness did not outyield rhizomatous populations of subsp. x varia which, in turn, had better spreading ability. In a subsequent evaluation, clones from selected rhizomatous genotypes had higher yield and better spreading ability than those from selected creeping genotypes. Under the given conditions, expression of creeping-rootedness was always erratic. The results point to the opportunity to pay greater attention to rhizomatous types in breeding grazing-tolerant cultivars

Limits on the Position Wander of Sgr A*

We present measurements with the VLBA of the variability in the centroid position of Sgr A* relative to a background quasar at 7-mm wavelength. We find an average centroid wander of 71 +/- 45 micro-arcsec for time scales between 50 and 100 min and 113 +/- 50 micro-arcsec for timescales between 100 and 200 min, with no secular trend. These are sufficient to begin constraining the viability of the hot-spot model for the radio variability of Sgr A*. It is possible to rule out hot spots with orbital radii above 15GM_SgrA*/c^2 that contribute more than 30% of the total 7-mm flux. However, closer or less luminous hot spots remain unconstrained. Since the fractional variability of Sgr A* during our observations was ~20% on time scales of hours, the hot-spot model for Sgr A*'s radio variability remains consistent with these limits. Improved monitoring of Sgr A*'s centroid position has the potential to place significant constraints upon the existence and morphology of inhomogeneities in a supermassive black hole accretion flow.Comment: 14 pages, 3 figures submitted to Ap

Rings and Jets around PSR J2021+3651: the `Dragonfly Nebula'

We describe recent Chandra ACIS observations of the Vela-like pulsar PSR J2021+3651 and its pulsar wind nebula (PWN). This `Dragonfly Nebula' displays an axisymmetric morphology, with bright inner jets, a double-ridged inner nebula, and a ~30" polar jet. The PWN is embedded in faint diffuse emission: a bow shock-like structure with standoff ~1' brackets the pulsar to the east and emission trails off westward for 3-4'. Thermal (kT=0.16 +/-0.02 keV) and power law emission are detected from the pulsar. The nebular X-rays show spectral steepening from Gamma=1.5 in the equatorial torus to Gamma=1.9 in the outer nebula, suggesting synchrotron burn-off. A fit to the `Dragonfly' structure suggests a large (86 +/-1 degree) inclination with a double equatorial torus. Vela is currently the only other PWN showing such double structure. The >12 kpc distance implied by the pulsar dispersion measure is not supported by the X-ray data; spectral, scale and efficiency arguments suggest a more modest 3-4 kpc.Comment: 22 pages, 5 figures, 3 tables, Accepted to Ap