10,809 research outputs found

    Mechanism of Reconnection on Kinetic Scales Based on Magnetospheric Multiscale Mission Observations

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    We examine the role that ions and electrons play in reconnection using observations from the Magnetospheric Multiscale (MMS) mission on kinetic ion and electron scales, which are much shorter than magnetohydrodynamic scales. This study reports observations with unprecedented high resolution that MMS provides for magnetic eld (7.8 ms) and plasma (30 ms for electrons and 150 ms for ions). We analyze and compare approaches to the magnetopause in 2016 November, to the electron diffusion region in the magnetotail in 2017 July followed by a current sheet crossing in 2018 July. Besides magnetic eld reversals, changes in the direction of the ow velocity, and ion and electron heating, MMS observed large uctuations in the electron ow speeds in the magnetotail. As expected from numerical simulations, we have veried that when the eld lines and plasma become decoupled a large reconnecting electric eld related to the Hall current (110 mV/m) is responsible for fast reconnection in the ion diffusion region. Although inertial accelerating forces remain moderate (12 mV/m), the electric elds resulting from the divergence of the full electron pressure tensor provide the main contribution to the generalized Ohms law at the neutral sheet (as large as 200 mV/m). In our view, this illustrates that when ions decouple electron physics dominates. The results obtained on kinetic scales may be useful for better understanding the physical mechanisms governing reconnection processes in various magnetized laboratory and space plasmas

    Rural-urban migration in d-dimensional lattices

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    The rural-urban migration phenomenon is analyzed by using an agent-based computational model. Agents are placed on lattices which dimensions varying from d=2 up to d=7. The localization of the agents in the lattice define their social neighborhood (rural or urban) not being related to their spatial distribution. The effect of the dimension of lattice is studied by analyzing the variation of the main parameters that characterizes the migratory process. The dynamics displays strong effects even for around one million of sites, in higher dimensions (d=6, 7).Comment: 9 pages, 7 figures, to be published in International Journal of Modern Physics C 1

    In Vivo Study Of Novel Nanocomposite For Prostate Cancer Treatment

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    Because of high occurrence of side effects of conventional anticancer drugs, new therapies have been widely studied, such as the use of non-usual molecules and the association with nanomaterials. In this context, sildenafil is a molecule that has been lately considered as a co-adjuvant in cancer therapy because it inhibits an enzyme with a potential role in tumor progression, phosphodiesterase-5. Taking into account the combination of nanoparticles and sildenafil, we produced systems based on mesoporous silica nanoparticles, Pluronic F-127 and sildenafil as the main therapy for prostate cancer.61

    In Vivo Nanotoxicology Of Hybrid Systems Based On Copolymer/silica/anticancer Drug

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    One of the major problems in cancer therapies is the high occurrence of side effects intrinsic of anticancer drugs. Doxorrubicin is a conventional anticancer molecule used to treat a wide range of cancer, such as breast, ovarian and prostate. However, its use is associated with a number of side effects like multidrug resistance and cardiotoxicity. The association with nanomaterials has been considered in the past decade to overcome the high toxicity of these drugs. In this context, mesoporous silica nanoparticles are great candidates to be used as carriers once they are very biocompatible. Taking into account the combination of nanoparticles and doxorrubicin, we treated rats with chemically induced prostate cancer with systems based on mesoporous silica nanoparticles and a thermoreversible block copolymer (Pluronic F-127) containing doxorrubicin. Preliminary results show a possible improvement in tumor conditions proportional to the concentration of the nanoparticles, opening a perspective to use mesoporous silica nanoparticles as carrier for doxorrubicin in prostate cancer treatment.61

    The impact of the implementation of an integrated crop-livestock-forest system in a Ferralsol of the brazilian savannah (Cerrado).

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    This study aimed to contribute to the analysis of an iCLF system in the Brazilian savannah in Goiás state.Coordenador Roberto Giolo de Almeida. II SIGEE

    Avaliação do efeito da adubação NPK no crescimento de gravioleira (Annona muricata L.) nas condições edafoclimáticas do município de São Francisco do Pará.

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    In: FRAZÃO, D. A. C.; HOMMA, A. K. O; VIÉGAS, I. de J. M. (Ed.). Contribuição ao desenvolvimento da fruticultura na Amazônia. Belém, PA: Embrapa Amazônia Oriental, 2006. p. 557-561
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