1,857 research outputs found

    The Use of a PEG/Ascorbate Booster Following Standard Bowel Preparation Improves Visualization for Capsule Endoscopy in a Randomized, Controlled Study

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    Background/aims: The increasing use of capsule endoscopy (CE) to examine the gastrointestinal tract highlights the need to establish intestinal preparations that ensure optimal visualization while maximizing patient adherence. Thus, we assessed whether bowel preparation involving dietary restriction and a booster regimen produces adequate CE visualization in a real-world clinical setting. Methods: We conducted a randomized, double-blind, prospective study of CE procedures at 2 tertiary-care centers. Patients were allocated to 3 groups: group 1 followed a clear liquid diet and fasting-based bowel preparation for the exploration (n = 55); group 2 followed the same procedure as group 1 and then ingested 1 L of a polyethylene glycol (PEG)/ascorbic acid booster solution when the capsule reached the small intestine (n = 55); and group 3 followed the same procedure but ingesting only 0.5 L of the booster solution (n = 56). The quality of visualization and the average gastric, orocecal and small-bowel transit times were evaluated. Results: A total of 166 patients participated in the study. Significantly higher quality of visualization (Park score) was obtained in group 3 (2.28 ± 0.59) than in group 1 (1.84 ± 0.54, P < .001), while there were no significant differences in the average gastric (range: 36.58- 48.32 min, P = .277), orocecal (range: 322.58-289.45 min, P = .072), and small-bowel transit time (range: 280.71-249.95 min, P = .286) between the 3 groups. Conclusions: Following a clear liquid diet and fasting-based bowel preparation for CE exploration, administering a booster solution of PEG/ascorbic acid after the capsule had reached the small intestine improves mucosal visualization and cleansing without affecting capsule transit times.info:eu-repo/semantics/publishedVersio

    Rumo às boas práticas.

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    Work and Quantum Phase Transitions: Is there Quantum Latency?

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    We study the physics of quantum phase transitions from the perspective of non-equilibrium thermodynamics. For first order quantum phase transitions, we find that the average work done per quench in crossing the critical point is discontinuous. This leads us to introduce the quantum latent work in analogy with the classical latent heat of first order classical phase transitions. For second order quantum phase transitions the irreversible work is closely related to the fidelity susceptibility for weak sudden quenches of the system Hamiltonian. We demonstrate our ideas with numerical simulations of first, second, and infinite order phase transitions in various spin chain models.Comment: accepted in PR

    Policy Traps: Consumer Subsidies in Post-Crisis Argentina

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    Developing countries devote significant resources to lowering consumer prices for basic goods and services such as food and electricity. Theories of the welfare state only partially elucidate why consumer subsidy regimes grow so large and become entrenched. While the welfare state literature stresses how concentrated, organized beneficiary groups push for the expansion and protection of well-known programs such as pensions, the developing world’s consumers are atomized, and subsidies themselves are of low visibility. The size and durability of consumer subsidy regimes stem primarily from political uncertainty and price shocks that provide politicians with strong incentives to avoid blame for repeal. Over time, environmental pressures and fears of political backlash against repeal reinforce one another, increasing the fiscal burden subsidies impose and dramatically raising the political cost of program exit. In this sense, consumer subsidy programs come to form “policy traps”—initially modest policies that quickly grow and become entrenched, thereby greatly reducing politicians’ maneuvering room. We utilize this framework to analyze the meteoric growth and entrenchment of utility subsidies in post-crisis Argentina. In Argentina, subsidies grew despite the private provision of subsidized services—making it difficult for the government to claim credit—even in sectors with weakly organized interests

    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

    Levantamento da infestação de plantas daninhas associada a uma pastagem cultivada de baixa produtividade no nordeste paraense.

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    A região do trópico úmido amazônico ocupa 350 milhões de hectares, constituindo a maior área de fronteira agrícola do planeta. A pecuária como exploração do uso da terra é a principal forma de ocupação e de desmatamento na região, apesar da baixa produtividade e das conseqüências ambientais. O declínio da produtividade da pastagem está associado, entre outras, ao manejo inadequado e à elevada infestação de plantas daninhas herbáceas e arbustivas, anuais ou perenes, geralmente denominadas ?juquira? na região. Se essas plantas não forem controladas adequadamente, podem levar à degradação da pastagem, resultando na completa perda de produtividade e no posterior abandono da área. Com o objetivo de identificar as plantas daninhas mais importantes que ocorrem em área de pastagem de baixa produtividade no município de Terra Alta, PA (0º 58? S e 47º 52? W. Gr.), foi efetuado um levantamento florístico em 0,33 ha de área cultivada com capim-quicuio-da-amazônia (Brachiaria humidicola). Foram registrados 4.700 indivíduos, distribuídos em 17 famílias botânicas, representadas por 36 espécies vegetais. Destacaram-se as famílias Poaceae, Rubiaceae, Fabaceae, Asteraceae e Solanaceae, sendo encontrado em cada uma delas cinco, cinco, quatro, três e três espécies, respectivamente. As plantas daninhas consideradas de maior importância na comunidade vegetal foram: Borreria verticillata, Hyptis atrorubens, Rolandra argentea, Desmodium canum, Panicum pilosum, Davilla rugosa, Imperata brasiliensis, Paspalum maritimum, Vernonia scorpioides e Vismia guianens

    Ensaio comparativo avançado de arroz irrigado (várzea) em Belém, Pará - ano agrícola 1998/1999.

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    Jaburu: cultivar de arroz lançada para o ecossistema de várzea no Estado do Pará.

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