868 resultados para min-max shadow maps


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We extend the renormalization operator introduced in [A. de Carvalho, M. Martens and M. Lyubich. Renormalization in the Henon family, I: universality but non-rigidity. J. Stat. Phys. 121(5/6) (2005), 611-669] from period-doubling Henon-like maps to Henon-like maps with arbitrary stationary combinatorics. We show that the renonnalization picture also holds in this case if the maps are taken to be strongly dissipative. We study infinitely renormalizable maps F and show that they have an invariant Cantor set O on which F acts like a p-adic adding machine for some p > 1. We then show, as for the period-doubling case in the work of de Carvalho, Martens and Lyubich [Renormalization in the Henon family, I: universality but non-rigidity. J. Stat. Phys. 121(5/6) (2005), 611-669], that the sequence of renormalizations has a universal form, but that the invariant Cantor set O is non-rigid. We also show that O cannot possess a continuous invariant line field.

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Let X be a compact Hausdorff space, Y be a connected topological manifold, f : X -> Y be a map between closed manifolds and a is an element of Y. The vanishing of the Nielsen root number N(f; a) implies that f is homotopic to a root free map h, i.e., h similar to f and h(-1) (a) = empty set. In this paper, we prove an equivariant analog of this result for G-maps between G-spaces where G is a finite group. (C) 2010 Elsevier B.V. All rights reserved.

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Trypanosoma cruzi, the agent of Chagas` disease, alternates between different morphogenetic stages that face distinct physiological conditions in their invertebrate and vertebrate hosts, likely in the availability of glucose. While the glucose transport is well characterized in epimastigotes of T cruzi, nothing is known about how the mammalian stages acquire this molecule. Herein glucose transport activity and expression were analyzed in the three developmental stages present in the vertebrate cycle of T cruzi. The infective trypomastigotes showed the highest transport activity (V(max) = 5.34 +/- 0.54 nmol/min per mg of protein: K(m) = 0.38 +/- 0.01 mM) when compared to intracellular epimastigotes (V(max) = 2.18 +/- 0.20 nmol/min per mg of protein; K(m) = 0.39 +/- 0.01 mM). Under the conditions employed no transport activity could be detected in amastigotes. The gene of the glucose transporter is expressed at the mRNA level in trypomastigotes and in intracellular epimastigotes but not in amastigotes, as revealed by real-time PCR. In both trypomastigotes and intracellular epimastigotes protein expression could be detected by Western blot with an antibody raised against the glucose transporter correlating well with the transport activity measured experimentally. Interestingly, anti-glucose transporter antibodies showed a strong reactivity with glycosome and reservosome organelles. A comparison between proline and glucose transport among the intracellular differentiation forms is presented. The data suggest that the regulation of glucose transporter reflects different energy and carbon requirements along the intracellular life cycle of T cruzi. (C) 2009 Elsevier B.V. All rights reserved.

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Neutral trehalase from Neurospora crassa was expressed in Escherichia coli as a polypeptide of similar to 84 kDa in agreement with the theoretical size calculated from the corresponding cDNA. The recombinant neutral trehalase, purified by affinity chromatography exhibited a specific activity of 80-150 mU/mg protein. Optima of pH and temperature were 7.0 and 30 degrees C, respectively. The enzyme was absolutely specific for trehalose, and was quite sensitive to incubation at 40 degrees C. The recombinant enzyme was totally dependent on calcium, and was inhibited by ATP, copper, silver, aluminium and cobalt. K(M) was 42 mM, and V(max) was 30.6 nmol of glucose/min. The recombinant protein was phosphorylated by cAMP-dependent protein kinase, but not significantly activated. Immunoblotting with polyclonal antiserum prepared against the recombinant protein showed that neutral trehalase protein levels increased during exponential phase of N. crassa growth and dropped at the stationary phase. This is the first report of a neutral trehalase produced in E. coli with similar biochemical properties described for fungi native neutral trehalases, including calcium-dependence. (C) 2008 Elsevier Inc. All rights reserved.

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Some sesquiterpene lactones (SLs) are the active compounds of a great number of traditionally medicinal plants from the Asteraceae family and possess considerable cytotoxic activity. Several studies in vitro have shown the inhibitory activity against cells derived from human carcinoma of the nasopharynx (KB). Chemical studies showed that the cytotoxic activity is due to the reaction of alpha,beta-unsaturated carbonyl structures of the SLs with thiols, such as cysteine. These studies support the view that SLs inhibit tumour growth by selective alkylation of growth-regulatory biological macromolecules, such as key enzymes, which control cell division, thereby inhibiting a variety of cellular functions, which directs the cells into apoptosis. In this study we investigated a set of 55 different sesquiterpene lactones, represented by 5 skeletons (22 germacranolides, 6 elemanolides, 2 eudesmanolides, 16 guaianolides and nor-derivatives and 9 pseudoguaianolides), in respect to their cytotoxic properties. The experimental results and 3D molecular descriptors were submitted to Kohonen self-organizing map (SOM) to classify (training set) and predict (test set) the cytotoxic activity. From the obtained results, it was concluded that only the geometrical descriptors showed satisfactory values. The Kohonen map obtained after training set using 25 geometrical descriptors shows a very significant match, mainly among the inactive compounds (similar to 84%). Analyzing both groups, the percentage seen is high (83%). The test set shows the highest match, where 89% of the substances had their cytotoxic activity correctly predicted. From these results, important properties for the inhibition potency are discussed for the whole dataset and for subsets of the different structural skeletons. (C) 2008 Elsevier Masson SAS. All rights reserved.

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Syftet med studien är att i utvalt material, FN:s deklaration om de mänskliga rättigheterna, FN:s barnkonvention samt Parliament of the World´s Religions dokument om global etik (DTGE), lokalisera en formulerad värdegrund rörande individens möjlighet till identitetsut-veckling, avsedd att tillämpas globalt i vår samtid. Jag har som ambition att försöka räta ut en del frågetecken rörande vilka rättigheter och möjligheter individen har enligt dokumenten till sin egen identitetsformering. Dessutom undersöker jag om materialets värdegrund kan kopp-las till problematiken om hur individens rätt till identitetsformering påverkar dennes formule-rade rätt till religionsfrihet och religioner. Studien är en litteraturstudie och metoden jag använt är en kombination av innehållsanalys och idéanalys som bearbetar material i form av litteratur och dokument rörande identitetsut-veckling. Materialet analyseras med hjälp av teoretiska redskap hämtade från tre författares olika synsätt på identitetsformering samt kringliggande problematik i ämnet. Då min studie även är av komparativ art har jag selekterat analysverktygen liksom primärkäl-lorna, efter tanken att med olika teoretikers perspektiv bemöta och besvara mina breda fråge-ställningar. Resultaten av analysen visar att alla människor inte har getts möjligheten till egen identitetsformering. Vilka av materialets värderingar angående individuell rätt till identitets-formering som kan kopplas till religionsfrihet eller religioner, var betydligt svårare att utröna, då dokumenten är mycket försiktiga i sin formulering rörande olika religioners inverkan på individens identitetsformeringsmöjligheter.

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Sociologisk Forsknings digitala arkiv

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The purpose of the study is, based on a narratological perspective, to analyze and interpret the novel written by Astrid Lindgren: Mio, min Mio. It is based on the legacy of the folktale tradition, which is also the basis for carnival concept according to Bachtin. The study is based on a narrative model of Gérard Genette. Mio, min Mio is told as a first person narrator and can be interpreted as Bo tells it to himself. It is a frame story in which the outer story is the reality, while the inner story is the structure of the folktale where Mio embarks on a predetermined mission to fight against evil. Carnival concept involves a timed up-and-down-turn that is sanctioned and controlled, this fits well with this story seen from this interpretation. In the fantasy world everything has an idealized counterpart and Bo is, via Mio, in this world for a limited time. Children in our society are powerless, but are allowed to be mighty in children's literature. The story gets a subversive effect as it shows that adult standards are not absolute. Even if Bo turns back to his foster parents, he goes through this inner battle processing his thoughts and feelings. The love Bo will experience in imagination gives him the power to manage his real situation.

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Denna uppsats undersöker olika musikaliskt hörbara kännetecken som är specifika i Max Martins produktioner. Musikaliska kännetecken refererar till hörbara kännetecken i den här uppsatsen och kommer att beröra formen på verket, tonart, rytm, frasindelningar, sångens dynamik, melodin och känslan som artisten framför i sången. Först analyseras tre produktioner producerade och skrivna av Max Martin och sedan jämförs de med tre stycken produktioner som är producerade och skrivna av andra producenter och låtskrivare. Analysen sker genom en så kallad ljudhändelsebeskrivning för att få fram material som går att jämföras och det sker med hjälp av den komparativa metoden. I resultatet går det tydligt att se musikaliskt hörbara kännetecken som är specifika i Max Martins produktioner. Det går även att se vilka musikaliskt hörbara kännetecken som är gemensamma för alla inspelningar som har analyserats i uppsatsen.

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Solar-powered vehicle activated signs (VAS) are speed warning signs powered by batteries that are recharged by solar panels. These signs are more desirable than other active warning signs due to the low cost of installation and the minimal maintenance requirements. However, one problem that can affect a solar-powered VAS is the limited power capacity available to keep the sign operational. In order to be able to operate the sign more efficiently, it is proposed that the sign be appropriately triggered by taking into account the prevalent conditions. Triggering the sign depends on many factors such as the prevailing speed limit, road geometry, traffic behaviour, the weather and the number of hours of daylight. The main goal of this paper is therefore to develop an intelligent algorithm that would help optimize the trigger point to achieve the best compromise between speed reduction and power consumption. Data have been systematically collected whereby vehicle speed data were gathered whilst varying the value of the trigger speed threshold. A two stage algorithm is then utilized to extract the trigger speed value. Initially the algorithm employs a Self-Organising Map (SOM), to effectively visualize and explore the properties of the data that is then clustered in the second stage using K-means clustering method. Preliminary results achieved in the study indicate that using a SOM in conjunction with K-means method is found to perform well as opposed to direct clustering of the data by K-means alone. Using a SOM in the current case helped the algorithm determine the number of clusters in the data set, which is a frequent problem in data clustering.

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http://digitalcommons.colby.edu/atlasofmaine2005/1013/thumbnail.jpg