15 research outputs found
Entangling power of quantized chaotic systems
We study the quantum entanglement caused by unitary operators that have
classical limits that can range from the near integrable to the completely
chaotic. Entanglement in the eigenstates and time-evolving arbitrary states is
studied through the von Neumann entropy of the reduced density matrices. We
demonstrate that classical chaos can lead to substantially enhanced
entanglement. Conversely, entanglement provides a novel and useful
characterization of quantum states in higher dimensional chaotic or complex
systems. Information about eigenfunction localization is stored in a graded
manner in the Schmidt vectors, and the principal Schmidt vectors can be scarred
by the projections of classical periodic orbits onto subspaces. The eigenvalues
of the reduced density matrices are sensitive to the degree of wavefunction
localization, and are roughly exponentially arranged. We also point out the
analogy with decoherence, as reduced density matrices corresponding to
subsystems of fully chaotic systems are diagonally dominant.Comment: 21 pages including 9 figs. (revtex
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Principles of Collaborative Education Research with Stakeholders: Toward Requirements for a New Research and Development Infrastructure
A group of collaborative forms of education research sits uneasily within the existing infrastructure for research and development in the United States. Members of this group hold themselves to account to ways of working with schools, families, and communities different from the research models promoted in U.S. policies and endorsed by U.S. federal agencies. Those models privilege individual investigators’ priorities for research and regularly yield products and findings with little relevance to practice. Four such models are reviewed in this paper: the Strategic Education Research Partnership, Design-Based Implementation Research, Improvement Science within Networked Improvement Communities, and Community-Based Design Research. Through a participatory process involving developers and advocates for these group members’ approaches, we identified a set of interconnected principles related to collaboration, problem solving, and research. Further, we reviewed evidence for the embodiment of these principles in from four U.S. projects belonging to these approaches by examining a total of 13 journal articles, reports, and book chapters published between 2008 and 2018. Understanding, building, and supporting enactments of these principles is a worthwhile endeavor because there is evidence that these approaches to research can promote agency and equity in education. However, supporting these principles requires criteria for judging quality, which peers can use to evaluate individual studies or sets of research; new outcomes by which to measure progress; new venues for developing and giving accounts of research; and an appreciation for the value of developing and cultivating relationships with educators, families, and communities as an integral part of research.</p
Abnormal modulation of cell protective systems in response to ischemic/reperfusion injury is important in the development of mouse sickle cell hepatopathy
Background/aim. Sickle cell disease is a worldwide-distributed autosomal recessive genetic red cell disorder. Hepatic dysfunction and liver damage is present in sickle cell disease, but its pathogenesis is only partially known.
Design and Methods. Transgenic mouse model for sickle cell disease (SAD mice) and wild-type mice were exposed to ischemic/reperfusion protocol. The following parameters were evaluated: hematological profile, transaminases and bilirubin levels, liver pathology, mRNA levels of nuclear factor-kB p65, endothelial NO synthase, inducible NO synthase, heme oxygenase-1 and phosphodiesterase-1-2-3-4 genes in hepatocytes obtained by laser-capture-microdissection. Protein expression of nuclear factor-kB p65 and phospho- nuclear factor-kB p65, heme oxygenase-1, biliverdin reductase, heat-shock-protein-70,-27 and peroxiredoxin-6 were analysed by immunoblot. A subgroup of SAD mice was treated with the phosphodiesterase-4 inhibitor Rolipram (30 mg/Kg/day by gavage) during the ischemic/reperfusion stress.
Results. In SAD mice the ischemic/reperfusion stress induced liver damage compatible with sickle cell disease hepatopathy, which was associated with (i) lack of hypoxia induced nuclear factor-kB p65 activation; (ii) unbalance in endothelial /inducible NO synthase response to ischemic/reperfusion stress; (iii) lack of hypoxia induced heme oxygenase-1/ biliverdin reductase increased expression paralleled by the compensatory increased in heat-shock-protein-70,-27 and peroxiredoxin-6 expression; (iv) up-regulation of the phosphodiesterase-1,-2,-3,-4 genes. In SAD mice the phosphodiesterase-4 inhibitor Rolipram attenuates the ischemic/reperfusion related microcirculatory dysfunction, reduces the inflammatory cell infiltration and induced the heme oxygenase-1/ biliverdin reductase cytoprotective systems.
Conclusions. In SAD mice, sickle cell hepatopathy is associated with perturbation of nuclear factor-kB p65 signalling with imbalance of endothelial /inducible nitric oxide synthase levels, lack of heme oxygenase-1/ biliverdin reductase expression and up-regulation of two novel cytoprotective systems: heat-shock-protein-27 and peroxiredoxin-6
Avaliação de programas hormonais para a indução e sincronização do estro em caprinos Evaluation of hormonal programs to induce and synchronize estrus in goats
O objetivo deste trabalho foi estabelecer alternativas para indução e sincronização do estro em cabras leiteiras manejadas semi-intensivamente. Foram conduzidos quatro experimentos com 411 cabras na Embrapa-Centro Nacional de Pesquisa deCaprinos, Sobral, CE. No protocolo básico, utilizaram-se esponjas intra-vaginais com 50 mg de acetato de medroxiprogesterona (MAP) por dez dias e aplicação intra-muscular de 100 mig de cloprostenol e 200 UI de gonadotropina coriônica eqüina (eCG) no 8º dia; a inseminação artificial (IA), com sêmen congelado foi feita 38 horas após remoção da esponja. No experimento1 substituiu-se a e CG pelo "efeito macho"; no experimento 2 substituiu-se a dose de MAP para 60 mg; no experimento3 compararam-se diferentes momentos de IA: 38, 44 e 50 horas e no experimento 4 substituiu-se a eCG pela gonadotropina humana (hCG). Nenhuma das alternativas testadas modificou (P>0,05) a prolificidade. A IA em cio natural gerou maior (P<0,05) índice de parição no experimento2(67,7%) e no experimento 4 (73,3%). A dose de 60 mg de MAP permitiu realizar a IA mais tarde (44 horas apósretirar a esponja) sem detrimento da fertilidade. A hCG equivaleu a eCG, se aplicada 48 horas antes de retirar a esponja.<br>The objective of this study was to establish alternatives to induce and synchronize estrus in dairy goats managed under semi-intensive conditions. Four experiments were carried out using 411 goats at the Embrapa-Centro Nacional de Pesquisa de Caprinos, Sobral, CE, Brazil. In the basic protocol, intra-vaginal sponges were used with 50 mg of medroxyprogesterone acetate (MAP) over ten days, associated with intra-muscular shots of cloprostenol, and equine corionic gonadotropin (eCG) at the 8th day. Artificial insemination (AI) with frozen semen took place 38 hours after sponge withdrawal. In the first experiment, eCG was replaced by "buck effect"; in the second experiment, 60 mg MAP replaced the usual dose; the third experiment compared different pre-fixed time for AI: 38, 44 and 50 hours and in the fourth experiment, hCG (human corionic gonadotropin) given at different moments, replaced eCG. Prolificacy was not influenced (P>0.05) by any changes of basic protocol.After natural estrus, AIprovided higher (P<0.05) parturition rates in the second (67.7%) and fourth experiment (73.3%). Sponge with 60mg MAP allowed to inseminate later (44 hours after removal) without impairing fertility. As long as hCG is given 48 hours before sponge removal it results equals to eCG ones