6,608 research outputs found
Overcoming ambiguities in classical and quantum correlation measures
We identify ambiguities in the available frameworks for defining quantum,
classical, and total correlations as measured by discordlike quantifiers. More
specifically, we determine situations for which either classical or quantum
correlations are not uniquely defined due to degeneracies arising from the
optimization procedure over the state space. In order to remove such
degeneracies, we introduce a general approach where correlations are
independently defined, escaping therefore from a degenerate subspace. As an
illustration, we analyze the trace-norm geometric quantum discord for two-qubit
Bell-diagonal states.Comment: 5 pages, 2 figures. v2: Minor corrections. Published versio
A intervenção da DGEMN nos Paços Arquiepiscopais de Braga: restaurar a memória da Nação
info:eu-repo/semantics/draf
Dark/Visible Parallel Universes and Big Bang Nucleosynthesis
We develop a model for visible matter-dark matter interaction based on the
exchange of a massive gray boson called herein the Mulato. Our model hinges on
the assumption that all known particles in the visible matter have their
counterparts in the dark matter. We postulate six families of particles five of
which are dark. This leads to the unavoidable postulation of six parallel
worlds, the visible one and five invisible worlds. A close study of big bang
nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB)
bounds, galaxy dynamics, together with the Standard Model assumptions, help us
to set a limit on the mass and width of the new gauge boson. Modification of
the statistics underlying the kinetic energy distribution of particles during
the BBN is also discussed. The changes in reaction rates during the BBN due to
a departure from the Debye-Hueckel electron screening model is also
investigated.Comment: Invited talk at the Workshops "CompStar: the physics and astrophysics
of compact stars", Tahiti, June 4-8, 2012, "New Directions in Nuclear
Astrophysics", Castiglion Fiorentino, Italy, June 18-22, 2012, and
"Carpathian Summer School of Physics", Sinaia, Romania, June 24 - July 7,
2012. To be published in AIP Proceeding
Geometric classical and total correlations via trace distance
We introduce the concepts of geometric classical and total correlations
through Schatten 1-norm (trace norm), which is the only Schatten p-norm able to
ensure a well-defined geometric measure of correlations. In particular, we
derive the analytical expressions for the case of two-qubit Bell-diagonal
states, discussing the superadditivity of geometric correlations. As an
illustration, we compare our results with the entropic correlations, discussing
both their hierarchy and monotonicity properties. Moreover, we apply the
geometric correlations to investigate the ground state of spin chains in the
thermodynamic limit. In contrast to the entropic quantifiers, we show that the
classical correlation is the only source of 1-norm geometric correlation that
is able to signaling an infinite-order quantum phase transition.Comment: v2: published versio
Erupted Complex Odontoma Mimicking a Mandibular Second Molar
Complex odontoma (CO) is considered one of the most common odontogenic lesions, composed by a miscellaneous of dental tissue such as enamel, dentin, pulp and sometimes cementum. They may interfere with the eruption of an associated tooth, being more prevalent in the posterior mandible. CO has been rarely reported as erupted, being considered an intraosseous lesion. This is a case report of a 17-year-old male with a benign fibro-osseous lesion consistent with CO that was located at the left second molar region, above the crown of the impacted mandibular second molar tooth. The lesion was surgically removed, and the tooth had to be extracted, since there was no indication that it could erupt naturally or with orthodontic traction. The histopathological examination confirmed the diagnosis of CO and after 6 months complete bone formation was observed radiographically. An early diagnosis will provide a better treatment option, avoiding tooth extraction or a more damaging surgery
Gold@mesoporous silica nanocarriers for the effective delivery of antibiotics and by-passing of β-lactam resistance
POCI-01-0145-FEDER-007265
PD/BD/142865/2018
CEECIND/00648/2017
UIDB/04077/2020
Sem PDF conforme despacho.Current antibiotics effectiveness relies on higher doses and administration frequency, which are responsible for the growth of antimicrobial resistance (AMR). AMR is one of the major threatening issues of the century with last-line antibiotics already failing. To overcome such problems associated with bacterial infections, nanoparticles combined with antibiotics emerged as a promising strategy. In this work, nanocarriers comprising of gold–silica core–shell mesoporous nanoparticles (Au@MNs) and silica mesoporous nanoparticles (MNs) were synthesized, loaded with amoxicillin (Amox) and ofloxacin and investigated regarding its antibacterial activity towards S. aureus, methicillin-resistant S. aureus (MRSA), E. coli and P. aeruginosa. Both nanocarriers showed a beneficial role in the effective delivery of amoxicillin against MRSA and the well-known β-lactam resistant P. aeruginosa. Reductions of 10-fold (Amox@MNs) and 20-fold (Amox@Au@MNs) in the amount of antibiotic to treat P. aeruginosa; and a reduction of 20-fold (Amox@MNs) towards MRSA allied to a full reversion of resistance, strongly supports the promising potential of these nanocarriers to tackle antibiotics resistance.publishersversionpublishe
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