1,415 research outputs found

    Two-scale convergence for locally-periodic microstructures and homogenization of plywood structures

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    The introduced notion of locally-periodic two-scale convergence allows to average a wider range of microstructures, compared to the periodic one. The compactness theorem for the locally-periodic two-scale convergence and the characterisation of the limit for a sequence bounded in H1(Ω)H^1(\Omega) are proven. The underlying analysis comprises the approximation of functions, which periodicity with respect to the fast variable depends on the slow variable, by locally-periodic functions, periodic in subdomains smaller than the considered domain, but larger than the size of microscopic structures. The developed theory is applied to derive macroscopic equations for a linear elasticity problem defined in domains with plywood structures.Comment: 22 pages, 4 figure

    Watermelon stomach seen by wireless‐capsule endoscopy

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    Endoscopy. 2003 Jan;35(1):100. Watermelon stomach seen by wireless-capsule endoscopy. Mascarenhas-Saraiva M, Lopes L, Mascarenhas-Saraiva A. SourceDigestive Endoscopy and Motility Unit, Trindade Hospital, Rua Trinidade 115, 4000-541 Porto, Portugal. [email protected] PMID:12510242[PubMed - indexed for MEDLINE

    A Fabry-Perot interferometer with quantum mirrors: nonlinear light transport and rectification

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    Optical transport represents a natural route towards fast communications, and it is currently used in large scale data transfer. The progressive miniaturization of devices for information processing calls for the microscopic tailoring of light transport and confinement at length scales appropriate for the upcoming technologies. With this goal in mind, we present a theoretical analysis of a one-dimensional Fabry-Perot interferometer built with two highly saturable nonlinear mirrors: a pair of two-level systems. Our approach captures non-linear and non-reciprocal effects of light transport that were not reported previously. Remarkably, we show that such an elementary device can operate as a microscopic integrated optical rectifier

    Unexpected angiographic and visual findings after clipping of a carotid-ophthalmic aneurysm

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    A 56-year-old woman underwent surgery for a ruptured carotid-ophthalmic artery aneurysm. Intraoperative visual inspection confirmed that the ophthalmic artery was left intact. She had no light perception on the operated side right after surgery. Angiography one week after surgery confirmed exclusion of the aneurysm, no filling of the proximal portion of the ophthalmic artery, and a very faint filling of its distal orbital part. She gradually recovered from this deficit and 9 months after surgery she is capable of counting fingers. At this time angiography displayed filling of all the portions of the ophthalmic artery, absence of recruitment of collateral blood supply, and exclusion of the aneurysm as before. Surgical manipulation seems to either have induced vasospasm or thrombosis of the ophthalmic artery. Regression of vasospasm or secondary recanalization of the thrombus without development of collateral blood supply may account for the gradual improvement of vision. A risk of monocular blindness is associated with the surgical treatment of para-clinoid aneurysms. Nevertheless, when it occurs, a perspective of recovery may exist if certain etiologies are involved

    Equilibrium and Disorder-induced behavior in Quantum Light-Matter Systems

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    We analyze equilibrium properties of coupled-doped cavities described by the Jaynes-Cummings- Hubbard Hamiltonian. In particular, we characterize the entanglement of the system in relation to the insulating-superfluid phase transition. We point out the existence of a crossover inside the superfluid phase of the system when the excitations change from polaritonic to purely photonic. Using an ensemble statistical approach for small systems and stochastic-mean-field theory for large systems we analyze static disorder of the characteristic parameters of the system and explore the ground state induced statistics. We report on a variety of glassy phases deriving from the hybrid statistics of the system. On-site strong disorder induces insulating behavior through two different mechanisms. For disorder in the light-matter detuning, low energy cavities dominate the statistics allowing the excitations to localize and bunch in such cavities. In the case of disorder in the light- matter coupling, sites with strong coupling between light and matter become very significant, which enhances the Mott-like insulating behavior. Inter-site (hopping) disorder induces fluidity and the dominant sites are strongly coupled to each other.Comment: about 10 pages, 12 figure

    Emergence of classicality in small number entangled systems

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    We show the transition from a fully quantized interaction to a semiclassical one in entangled small number quantum systems using the quantum trajectories approach. In particular, we simulate the microwave Ramsey zones used in Rydberg atom interferometry, filling in the gap between the strongly entangling Jaynes Cummings evolution and the semiclassical rotation of the atomic internal states. We also correlate the information flowing with leaking photons to the entanglement generation between cavity field and flying atom and detail the roles played by the strong dissipation and the external driving force in preserving atomic coherence through the interaction.Comment: 4 pages, 6 figure

    Characterization of CYP2C19*17 polymorphism in a Portuguese population sample relevant for proton pump inhibitor therapy : a pilot study

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    Communication abstract: Proceedings of the 5th International Congress of CiiEM - Reducing inequalities in Health and Society, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from June 16th to 18th, 2021.This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The interindividual variability of Proton Pump Inhibitor (PPI) therapy results from the phenotype variability associated with the cytochrome P450 2C19 (CYP2C19) gene, namely the CYP2C19*17 allele. Our aim was to characterize patients’ genetic variability undergoing PPI therapy. A sample of 33 oral mucosa cells from Portuguese pharmacy patients was collected, followed by genotyping. The allelic frequencies of CYP2C19*1 (-806C) and CYP2C19*17 (-806T) were 71.2% and 28.8%, respectively. The genotypic frequencies for CYP2C19*1/*1 and CYP2C19*1/*17 were 42.4% and 57.6%, respectively, and 19 of these patients may have a Rapid Metabolizer (RM) phenotype pharmaceutical opinion letter, based on genetic evidence.info:eu-repo/semantics/publishedVersio

    Methods for delivering the UK's multi-centre prison-based naloxone-on-release pilot randomised trial (N-ALIVE): Europe's largest prison-based randomised controlled trial

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    INTRODUCTION AND AIMS: Naloxone is an opioid antagonist used for emergency resuscitation following opioid overdose. Prisoners with a history of heroin use by injection have a high risk of drug-related death in the first weeks after prison-release. The N-ALIVE trial was planned as a large prison-based randomised controlled trial (RCT) to test the effectiveness of naloxone-on-release in the prevention of fatal opiate overdoses soon after release. The N-ALIVE pilot trial was conducted to test the main trial's assumptions on recruitment of prisons and prisoners, and the logistics for ensuring that participants received their N-ALIVE pack on release. DESIGN AND METHODS: Adult prisoners who had ever injected heroin, were incarcerated for ≥7 days and were expected to be released within 3 months were eligible. Participants were randomised to receive, on liberation, a pack containing a single 'rescue' injection of naloxone or a control pack with no naloxone syringe. The trial was double-blind prior to prison-release. RESULTS: We randomised 1685 prisoners (842 naloxone; 843 control) across 16 prisons in England. We stopped randomisation on 8 December 2014 because only one-third of administrations of naloxone-on-release were to the randomised ex-prisoner; two-thirds were to others whom we were not tracing. DISCUSSION AND CONCLUSIONS: Prevention RCTs are seldom conducted within prisons; we demonstrated the feasibility of conducting a multi-prison RCT to prevent fatality from opioid overdose in the outside community. We terminated the N-ALIVE trial due to the infeasibility of individualised randomisation to naloxone-on-release. Large RCTs are feasible within prisons

    Produtividade econômica e componentes da produção de espigas verdes de milho em função da adubação nitrogenada.

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    Foi avaliado, durante dois anos, o efeito de doses de nitrogênio (N) na produtividade de espigas verdes de milho e em componentes da sua produção. Cinco doses de N (0, 60, 120, 180 e 240 kg ha-1) aplicadas em cobertura foram testadas num delineamento experimental de blocos casualizados, com quatro repetições. Foram avaliadas a produção e o número de espigas comerciais com palha por hectare, peso das espigas com e sem palha, comprimento e diâmetro de espigas sem palha e relação espiga com palha/palha. Aumentos na produtividade de espigas comerciais com palha com a aplicação de N foram encontrados, sendo estimadas as máximas produtividades de 13,52 t ha-1 com a dose de 157 kg ha-1 de N (primeiro ano) e de 14,86 t ha-1 com a dose de 177 kg ha-1 de N (segundo ano). Os aumentos na produtividade de espigas não foram devido aos aumentos do número de espigas por área e do comprimento destas, que não foram afetados pela adubação nitrogenada. Diferentemente da relação espiga/palha, o peso e o diâmetro das espigas foram influenciados pela elevação das doses de N. Foi proposta uma tabela de recomendação de adubação nitrogenada nos moldes de preços preestabelecidos de N e de espigas
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