Vortex Viscosity in Magnetic Superconductors Due to Radiation of Spin Waves

In type-II superconductors that contain a lattice of magnetic moments, vortices polarize the magnetic system inducing additional contributions to the vortex mass, vortex viscosity, and vortex-vortex interaction. Extra magnetic viscosity is caused by radiation of spin waves by a moving vortex. Like in the case of Cherenkov radiation, this effect has a characteristic threshold behavior and the resulting vortex viscosity may be comparable to the well-known Bardeen-Stephen contribution. The threshold behavior leads to an anomaly in the current-voltage characteristics, and a drop in dissipation for a current interval that is determined by the magnetic excitation spectrum.Comment: 4 pages, 1 figur

Behavior of the diffractive cross section in hadron-nucleus collisions

A phenomenological analysis of diffractive dissociation of nuclei in proton-nucleus and meson-nucleus collisions is presented. The theoretical approach employed here is able to take into account at once data of the HELIOS and EHS/NA22 collaborations that exhibit quite different atomic mass dependences. Possible extensions of this approach to hard diffraction in nuclear processes are also discussed.Comment: 5 pages, 2 figure

Alterations in brain connectivity due to plasticity and synaptic delay

Brain plasticity refers to brain's ability to change neuronal connections, as a result of environmental stimuli, new experiences, or damage. In this work, we study the effects of the synaptic delay on both the coupling strengths and synchronisation in a neuronal network with synaptic plasticity. We build a network of Hodgkin-Huxley neurons, where the plasticity is given by the Hebbian rules. We verify that without time delay the excitatory synapses became stronger from the high frequency to low frequency neurons and the inhibitory synapses increases in the opposite way, when the delay is increased the network presents a non-trivial topology. Regarding the synchronisation, only for small values of the synaptic delay this phenomenon is observed

Bioeletricidade no setor sucroalcooleiro paulista: participação no mercado de carbono, perspectivas e sustentabilidade.

bitstream/item/12264/1/documentos_78.pd

Multilingual simultaneous sentence end and punctuation prediction

This paper describes the model and its corresponding setup, proposed by the Unbabel & INESC-ID team for the 1st Shared Task on Sentence End and Punctuation Prediction in NLG Text (SEPP-NLG 2021). The shared task covers 4 languages (English, German, French and Italian) and includes two subtasks: Subtask 1 - detecting the end of a sentence, and subtask 2 - predicting a range of punctuation marks. Our team proposes a single multilingual and multitask model that is able to produce suitable results for all the languages and subtasks involved. The results show that it is possible to achieve state-of-the-art results using one single multilingual model for both tasks and multiple languages. Using a single multilingual model to solve the task for multiple languages is of particular importance, since training a different model for each language is a cumbersome and time-consuming process.info:eu-repo/semantics/publishedVersio

Avaliação preliminar de cultivares de aveia na região de São Carlos-SP.

Resumo

Exact Bond Ordered Ground State for the Transition Between the Band and the Mott Insulator

We derive an effective Hamiltonian $H_{eff}$ for an ionic Hubbard chain, valid for $t\ll U,\Delta$, where $t$ is the hopping, $U$ the Coulomb repulsion, and $\Delta$ the charge transfer energy. $H_{eff}$ is the minimal model for describing the transition from the band insulator (BI) ($\Delta -U\gg t$) and the Mott insulator (MI) ($U-\Delta \gg t$). Using spin-particle transformations (Phys. Rev. Lett. \textbf{86}, 1082 (2001)), we map $H_{eff}(U=\Delta)$ into an SU(3) antiferromagnetic Heisenberg model whose exact ground state is known. In this way, we show rigorously that a spontaneously dimerized insulating ferroelectric phase appears in the transition region between the BI and MI

Geometric Frustration and Dimensional Reduction at a Quantum Critical Point

We show that the spatial dimensionality of the quantum critical point associated with Bose--Einstein condensation at T=0 is reduced when the underlying lattice comprises a set of layers coupled by a frustrating interaction. Our theoretical predictions for the critical temperature as a function of the chemical potential correspond very well with recent measurements in BaCuSi$_{2}$O$_{6}$ [S. E. Sebastian \textit{et al}, Nature \textbf{411}, 617 (2006)].Comment: 5 pages, 2 figure