14,527 research outputs found
Identifying Emotions in Social Media: Comparison of Word-emotion lexica
In recent years, emotions expressed in social media messages have become a vivid research topic due to their influence on the spread of misinformation and online radicalization over online social networks. Thus, it is important to correctly identify emotions in order to make inferences from social media messages. In this paper, we report on the performance of three publicly available word-emotion lexicons (NRC, DepecheMood, EmoSenticNet) over a set of Facebook and Twitter messages. To this end, we designed and implemented an algorithm that applies natural language processing (NLP) techniques along with a number of heuristics that reflect the way humans naturally assess emotions in written texts. In order to evaluate the appropriateness of the obtained emotion scores, we conducted a questionnaire-based survey with human raters. Our results show that there are noticeable differences between the performance of the lexicons as well as with respect to emotion scores the human raters provided in our surve
Little-Parks oscillations near a persistent current loop
We investigate the Little-Parks oscillations caused by a persistent current
loop set on the top edge of a mesoscopic superconducting thin-walled cylinder
with a finite height. For a short cylinder the Little-Parks oscillations are
approximately the same ones as the standard effect, as there is only one
magnetic flux piercing the cylinder. For a tall cylinder the inhomogeneity of
the magnetic field makes different magnetic fluxes pierce the cylinder at
distinct heights and we show here that this produces two distinct Little-Parks
oscillatory regimes according to the persistent current loop. We show that
these two regimes, and also the transition between them, are observable in
current measurements done in the superconducting cylinder. The two regimes stem
from different behavior along the height, as seen in the order parameter,
numerically obtained from the Ginzburg-Landau theory through the finite element
methodComment: 13 pages, 12 figure
Nonthermal hard X-ray excess in the Coma cluster: resolving the discrepancy between the results of different PDS data analyses
The detection of a nonthermal excess in the Coma cluster spectrum by two
BeppoSAX observations analyzed with the XAS package (Fusco-Femiano et al.) has
been disavowed by an analysis (Rossetti & Molendi) performed with a different
software package (SAXDAS) for the extraction of the spectrum. To resolve this
discrepancy we reanalyze the PDS data considering the same software used by
Rossetti & Molendi. A correct selection of the data and the exclusion of
contaminating sources in the background determination show that also the SAXDAS
analysis reports a nonthermal excess with respect to the thermal emission at
about the same confidence level of that obtained with the XAS package
(~4.8sigma). Besides, we report the lack of the systematic errors investigated
by Rossetti & Molendi and Nevalainen et al. taking into account the whole
sample of the PDS observations off the Galactic plane, as already shown in our
data analysis of Abell 2256 (Fusco-Femiano, Landi & Orlandini). All this
eliminates any ambiguity and confirms the presence of a hard tail in the
spectrum of the Coma cluster.Comment: 12 pages, 2 figures. Accepted for publication in ApJ Letter
Secondary metabolites with ecologic and medicinal implications in Anthemis cretica subsp. petraea from Majella National Park
Anthemis cretica subsp. petraea (Ten.) Greuter is a plant belonging to the Asteraceae family and endemic of central Italy. In this paper, the first analysisof the ethanolic fraction of samples collected in the Majella National Park is reported. Seven compounds were isolated and identified namely parthenolide (1), 9α-acetoxyparthenolide (2), tamarixetin (3), 7-hydroxycoumarin (4), 4'-hydroxyacetophenone (5), leucanthemitol (conduritol F) (6),and proto-quercitol (7). Isolation of the compounds was achieved by means ofcolumn chromatography (CC), while their identification was achieved through spectroscopic and spectrometric techniques. The presence of these compounds is of great relevance. Compounds 1 and 2 are chemosystematic markers of the family, thus confirming the correct botanical classification of the species. Conversely, compounds 3, 5,and 7 were identified for the first time in the species and, instead, confirm the tendency of endemic entities to develop characteristic metabolite patterns in respect to cosmopolite species. Moreover, the presence of compounds 6 and 7 has ecologic implications and may be linked to this taxon’s adaption to dry environments. The production of these osmolytes may, in fact, represent the reason why this species is able to survive in extreme conditions of aridity. Lastly, from a medicinal standpoint, the isolated compounds are endowed with interesting biological activities and may justify, on a molecular base, the widespread traditional uses of the Anthemis species, as well as a basis for the use ofthe subspecies petraea
Entanglement between two superconducting qubits via interaction with non-classical radiation
We propose a scheme to physically interface superconducting nano-circuits and
quantum optics. We address the transfer of quantum information between systems
having different physical natures and defined in Hilbert spaces of different
dimensions. In particular, we investigate the transfer of the entanglement
initially in a non-classical state of a continuous-variable system to a pair of
superconducting charge qubits. This set-up is able to drive an initially
separable state of the qubits into an almost pure, highly entangled state
suitable for quantum information processing.Comment: 4 pages, RevTeX; revised versio
The Average Kinetic Energy of the Superconducting State
Isothermal magnetization curves are plotted as the magnetization times the
magnetic induction, , versus the applied field, H. We show
here that this new curve is the average kinetic energy of the superconducting
state versus the applied field, for type-II superconductors with a high
Ginzburg-Landau parameter . The maximum of occurs at
a field, , directly related to the upper critical field, ,
suggesting that may be extracted from such plots even in cases when
it is too high for direct measurement. We obtain these plots both
theoretically, from the Ginzburg-Landau theory, and experimentally, using a
Niobium sample with , and compare them.Comment: 11 pages, 9 postscript figure
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