967 resultados para Castellion, Sébastien, 1515-1563
Resumo:
This paper is aimed at designing a robust vaccination strategy capable of eradicating an infectious disease from a population regardless of the potential uncertainty in the parameters defining the disease. For this purpose, a control theoretic approach based on a sliding-mode control law is used. Initially, the controller is designed assuming certain knowledge of an upper-bound of the uncertainty signal. Afterwards, this condition is removed while an adaptive sliding control system is designed. The closed-loop properties are proved mathematically in the nonadaptive and adaptive cases. Furthermore, the usual sign function appearing in the sliding-mode control is substituted by the saturation function in order to prevent chattering. In addition, the properties achieved by the closed-loop system under this variation are also stated and proved analytically. The closed-loop system is able to attain the control objective regardless of the parametric uncertainties of the model and the lack of a priori knowledge on the system.
Resumo:
Computer vision algorithms that use color information require color constant images to operate correctly. Color constancy of the images is usually achieved in two steps: first the illuminant is detected and then image is transformed with the chromatic adaptation transform ( CAT). Existing CAT methods use a single transformation matrix for all the colors of the input image. The method proposed in this paper requires multiple corresponding color pairs between source and target illuminants given by patches of the Macbeth color checker. It uses Delaunay triangulation to divide the color gamut of the input image into small triangles. Each color of the input image is associated with the triangle containing the color point and transformed with a full linear model associated with the triangle. Full linear model is used because diagonal models are known to be inaccurate if channel color matching functions do not have narrow peaks. Objective evaluation showed that the proposed method outperforms existing CAT methods by more than 21%; that is, it performs statistically significantly better than other existing methods.
Resumo:
One of the main problems of fusion energy is to achieve longer pulse duration by avoiding the premature reaction decay due to plasma instabilities. The control of the plasma inductance arises as an essential tool for the successful operation of tokamak fusion reactors in order to overcome stability issues as well as the new challenges specific to advanced scenarios operation. In this sense, given that advanced tokamaks will suffer from limited power available from noninductive current drive actuators, the transformer primary coil could assist in reducing the power requirements of the noninductive current drive sources needed for current profile control. Therefore, tokamak operation may benefit from advanced control laws beyond the traditionally used PID schemes by reducing instabilities while guaranteeing the tokamak integrity. In this paper, a novel model predictive control (MPC) scheme has been developed and successfully employed to optimize both current and internal inductance of the plasma, which influences the L-H transition timing, the density peaking, and pedestal pressure. Results show that the internal inductance and current profiles can be adequately controlled while maintaining the minimal control action required in tokamak operation.
Resumo:
The feasibility of semi-intensive culture of Penaeus monodon in low saline environment was investigated by comparing the growth and production in low (0.16-6.52 ppt) and high (4.60-19.42 ppt) saline areas at two stocking densities (10.5 and 16 individuals/m super(2)). After 135 days of culture, yield of shrimp in low and high stocking densities was 1563.37 kg/ha and 2274 kg/ha, respectively, in low saline ponds, and 1173.00 and 1974.00 kg/ha, respectively in high saline ponds. Food conversion ratio (FCR, 1.31-1.58) and specific growth rate (SGR 21.04-21.19%) were higher in low saline ponds as compared to high saline ponds (FCR, 1.35-1.68; SGR, 19.22-19.88%). Growth of shrimp was satisfactory in low saline ponds even when salinity decreased after 60 days of culture to almost freshwater level (0.16 ppt) indicating the variability of semi-intensive culture of P. monodon in low saline environment.
Resumo:
No contexto da expansão ultramarina portuguesa no Oriente, a região do Maduré, localizada ao sul da Índia, também vivenciou a experiência política e, principalmente, religiosa a partir da presença da Companhia de Jesus nesse espaço. Em 1596, o jesuíta português Gonçalo Fernandes Trancoso tornou-se responsável por cuidar da comunidade cristã existente no Maduré, ganhando como companheiro de missão, em 1606, o jesuíta italiano Roberto de Nobili. A presente dissertação tem por objetivo central promover uma análise acerca das atuações missionárias dos jesuítas Gonçalo Fernandes Trancoso e Roberto de Nobili na missão do Maduré, no início do século XVII. Seus trabalhos missionários podem ser compreendidos a partir do estudo de suas narrativas sobre os costumes e práticas bramânicas, sendo possível identificar, para além das diferentes estratégias de conversão utilizadas por ambos inacianos, o modo como estes articularam seus conhecimentos sobre a sociedade indiana e o hinduísmo com o desenvolvimento de um projeto de conversão. Assim, destaca-se a falta homogeneidade no interior da Companhia de Jesus no que toca a práticas e métodos missionários.
Resumo:
植物络合素(phytochelatins,PCs)是含有γ-Glu-Cys重复结构的小分子多肽,其结构通式为:(γ-Glu-Cys)n-Gly(n=2-11)。植物络合素(PCs)由植物络合素合酶(PCS)催化谷胱甘肽(GSH)聚合而成,能够络合重金属离子而具有解毒功能,这是植物解毒重金属胁迫的重要机制之一。本文克隆了来源于重金属抗性植物绊根草(Cynodon dactylon cv Goldensun)的植物络合素合酶基因,通过基因工程手段使其在烟草中过量表达,得到了一些有望用于植物修复(phytoremediation)的工程植株。同时,在水稻(Oryza sativa)种子中利用RNAi技术抑制植物络合素合酶基因的表达,以降低重金属离子在人类最重要的粮食作物水稻的籽粒中的积累。 1. 通过RACE(Rapid Amplification of cDNA Ends)方法从抗性植物绊根草中克隆了植物络合素合酶基因CdPCS1,其1515 bp的读码框编码一个含505个氨基酸的蛋白质,蛋白质序列分析表明它具有植物络合素合酶的结构特征,同时还具有磷酸化位点和亮氨酸拉链结构。 2. CdPCS1基因可以互补对铜和镉离子敏感的酵母突变株ABDE-1(cup1Δ)中缺失的金属硫蛋白基因CUP1的功能,也可以互补对砷离子敏感的酵母突变体FD236-6A(acr-3Δ)中的离子外排载体基因ARC3的缺失。 3. 将CdPCS1转入烟草,共获得过表达CdPCS1的烟草44个株系,其中融合GFP的株系16个。对T0代的转基因植株的PCs含量以及重金属抗性和吸收能力进行了分析,其中抗性实验表明,在300μmol/L 的Cd2+离子胁迫11天之后,野生型植株的叶片出现斑点状坏死,而两个转基因烟草株系S6和K49的植株没有出现受伤害症状。在100μmol/L的CdSO4处理一周后,转基因植株中的PCs含量比对照有不同程度的提高,最多提高了2.88倍。当用300μmol/L Cd2+处理9天再用600μmol/L Cd2+处理2天后,Cd的积累量比野生型植株增加了2倍多;用50μmol/L As3+处理7天再用100μmol/L As3+处理2天后,转基因植株对As的积累量最多增加了3倍多。说明转入绊根草PC合酶基因的烟草增加了植物络合素的合成,并由此增加了对镉离子的抗性以及对镉离子和砷离子的积累。 4. 对转基因烟草中的CdPCS1进行了亚细胞定位研究。在激光共聚焦显微镜和荧光显微镜下分别用转基因烟草叶片组织和叶肉细胞原生质体观察融合GFP的CdPCS1,结果表明融合蛋白定位于细胞核中。 5. .利用RNAi技术抑制水稻种子中植物络合素合酶基因的表达,共获得39个转基因株系。其中35个株系为种子特异性ZMM1启动子驱动OsPCS1基因的RNAi,其余4个株系由组成型的Ubiquitin启动子驱动。RT-PCR的分析结果表明:一个由ZMM1启动子驱动的RNAi转基因水稻株系的种子中,OsPCS1的mRNA水平比对照中的下降了一半。