El debate público envenenado y los límites de la regulación estatal: por una alfabetización digital ante el problema de las fake news

In addition to the deliberate efforts to distort or misinform, the unintentional errors detected by thepublic —and the suspicion that there may be others not identified— have reinforced a skeptical stanceamong the public about the alleged veracity of the news. In the era of the so-called post-truth, it isno exaggeration to say that the main concern of the social sciences after the public debate has beencompletely hampered by the spread of false news and the supposed beginning of the collapse of liberaldemocracies, has been a collective sensation of shock, indignation. and despair at the increased prevalenceof false news. This paper focuses on the phenomenon of fake news, its effects in the context ofpolitical disputes and regulatory frameworks as an alleged solution. It is intended to demonstrate thatdigital literacy appears as the most adequate solution to mitigate this problem, without affecting freedomof expression in the public discursive sphere.Además de los esfuerzos deliberados por distorsionar o desinformar, los errores involuntarios detectadospor el público —y la sospecha de que pueda haber otros no identificados— han reforzado una posturaescéptica entre el público sobre la supuesta veracidad de la noticia. En la era de la llamada posverdad,no es exagerado decir que la principal preocupación de las ciencias sociales tras el debate público seve totalmente obstaculizada por la difusión de noticias falsas y el supuesto inicio del colapso de lasdemocracias liberales, ha sido una sensación colectiva de conmoción, indignación. y desesperación antela creciente prevalencia de noticias falsas. Este artículo se centra en el fenómeno de las fake news, susefectos en el contexto de las disputas políticas y los marcos regulatorios como supuesta solución. Sepretende demostrar que la alfabetización digital aparece como la solución más adecuada para mitigar esteproblema, sin afectar la libertad de expresión en el ámbito discursivo público

Quantum Correlations and Coherence in Spin-1 Heisenberg Chains

We explore quantum and classical correlations along with coherence in the ground states of spin-1 Heisenberg chains, namely the one-dimensional XXZ model and the one-dimensional bilinear biquadratic model, with the techniques of density matrix renormalization group theory. Exploiting the tools of quantum information theory, that is, by studying quantum discord, quantum mutual information and three recently introduced coherence measures in the reduced density matrix of two nearest neighbor spins in the bulk, we investigate the quantum phase transitions and special symmetry points in these models. We point out the relative strengths and weaknesses of correlation and coherence measures as figures of merit to witness the quantum phase transitions and symmetry points in the considered spin-1 Heisenberg chains. In particular, we demonstrate that as none of the studied measures can detect the infinite order Kosterlitz-Thouless transition in the XXZ model, they appear to be able to signal the existence of the same type of transition in the biliear biquadratic model. However, we argue that what is actually detected by the measures here is the SU(3) symmetry point of the model rather than the infinite order quantum phase transition. Moreover, we show in the XXZ model that examining even single site coherence can be sufficient to spotlight the second-order phase transition and the SU(2) symmetry point.Comment: 8 pages. 5 figure

Dynamical matrix for arbitrary quadratic fermionic bath Hamiltonians and non-Markovian dynamics of one and two qubits in an Ising model environment

We obtain the analytical expression for the Kraus decomposition of the quantum map of an environment modeled by an arbitrary quadratic fermionic Hamiltonian acting on one or two qubits, and derive simple functions to check the non-positivity of the intermediate map. These functions correspond to two different sufficient criteria for non-Markovianity. In the particular case of an environment represented by the Ising Hamiltonian, we discuss the two sources of non-Markovianity in the model, one due to the finite size of the lattice, and another due to the kind of interactions.Comment: 11 pages, 10 figure

Two-photon transitions driven by a combination of diode and femtosecond lasers

We report on the combined action of a cw diode laser and a train of ultrashort pulses when each of them drives one step of the 5S-5P-5D two-photon transition in rubidium vapor. The fluorescence from the 6P_{3/2} state is detected for a fixed repetition rate of the femtosecond laser while the cw-laser frequency is scanned over the rubidium D_{2} lines. This scheme allows for a velocity selective spectroscopy in a large spectral range including the 5D_{3/2} and 5D_{5/2} states. The results are well described in a simplified frequency domain picture, considering the interaction of each velocity group with the cw laser and a single mode of the frequency comb.Comment: 4 pages, 4 figure

Uso de óleos essenciais de cravo-da-índia, melaleuca, eucalipto e menta na sedação de peixe.

Com objetivo de avaliar o efeito no comportamento, tempo para sedação e tempo para recuperação de soluções preparadas com óleos essenciais extraídos de quatro tipos vegetais, com a finalidade de reduzir estresse dos peixes.Organizado por: Sílvio Ricardo Maurano; AQUACIÊNCIA 2012