1,146 research outputs found

    Geodynamics of the eastern sector of the Arrábida chain (W Portugal)

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    N.º4, p.263-267The Arrábida chain - located in the southern segment of the Lusitanian basin - is a S-wards directed fold and thrust belt of Miocene age of deformation. ENE-WSW striking frontal ramps and associated folds are connected to sinistral NNE-SSW and N-S striking lateral ramps, that show left-lateral and SE-wards reverse movements. Both frontal and oblique ramps form imbricate duplexes. Constriction increases SE-wards due to the presence of a basin boundary fault (SetúbaI- Pinhal Novo fault) that acts as a buttress to the oblique thrust movement. Kilometre scale transpressive structures can be observed along the basin boundary fault. A map scale sheath fold like structure can be observed at the Viso anticline, which is a consequence of a strong anisotropy contrast of the Mesocenozoic strata.The Arrábida chain thrusts migrated backward, i.e. to the north, according to an overstep model. Detailed geometrical reconstruction and kinematic analysis of the structures of the eastern region of Arrábida (Formosinho, Vise and Serra de S. Luis anticlines) show that a thin-skinned tectonic model (Ribeiro, A. et aI., 1990) fits very well with the geometry of the structures of the Arrábida chain

    Drawing and use of auxiliary projection nets (the program STEGRAPH)

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    The development of an algorithm for the construction of auxiliary projection nets (conform, equivalent and orthographic), in the equatorial and polar versions, is presented. The algorithm for the drawing of the "IGAREA 220" counting net (ALYES & MENDES, 1972), is also presented. Those algorithms are the base of STEGRAPH program (vers. 2.0), for MS-DOS computers, which has other applications

    Levy ratchets with dichotomic random flashing

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    Additive symmetric L\'evy noise can induce directed transport of overdamped particles in a static asymmetric potential. We study, numerically and analytically, the effect of an additional dichotomous random flashing in such L\'evy ratchet system. For this purpose we analyze and solve the corresponding fractional Fokker-Planck equations and we check the results with Langevin simulations. We study the behavior of the current as function of the stability index of the L\'evy noise, the noise intensity and the flashing parameters. We find that flashing allows both to enhance and diminish in a broad range the static L\'evy ratchet current, depending on the frequencies and asymmetry of the multiplicative dichotomous noise, and on the additive L\'evy noise parameters. Our results thus extend those for dichotomous flashing ratchets with Gaussian noise to the case of broadly distributed noises.Comment: 15 pages, 6 figure

    On the Relationship Between Iterated Statistical Linearization and Quasi-Newton Methods

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    This letter investigates relationships between iterated filtering algorithms based on statistical linearization, such as the iterated unscented Kalman filter (IUKF), and filtering algorithms based on quasi-Newton (QN) methods, such as the QN iterated extended Kalman filter (QN-IEKF). Firstly, it is shown that the IUKF and the iterated posterior linearization filter (IPLF) can be viewed as QN algorithms, by finding a Hessian correction in the QN-IEKF such that the IPLF iterate updates are identical to that of the QN-IEKF. Secondly, it is shown that the IPLF/IUKF update can be rewritten such that it is approximately identical to the QN-IEKF, albeit for an additional correction term. This enables a richer understanding of the properties of iterated filtering algorithms based on statistical linearization.Comment: 4 page

    Neighbourhoods as relational places for people living with dementia

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    An increase in the number of people living independently with dementia across the developed world has focused attention on the relevance of neighbourhood context for enabling or facilitating social health and wellbeing. Taking the lived experiences and daily realities of people living with dementia as a starting point, this paper contributes new understanding about the relevance of local places for supporting those living with the condition in the community. The paper outlines findings from a study of the neighbourhood experiences, drawing on new data collected from a creative blend of qualitatively-driven mixed methods with people living in a diverse array of settings across three international settings. The paper details some of the implications of neighbourhoods as sites of social connection for those living with dementia from material from 67 people living with dementia and 62 nominated care-partners. It demonstrates how neighbourhoods are experienced as relational places and considers how people living with dementia contribute to the production of such places through engagement and interactions in ways that may be beneficial to social health. We contend that research has rarely focused on the subjective, experiential and ‘everyday’ social practices that contextualise neighbourhood life for people living with dementia. In doing so, the paper extends empirical and conceptual understanding of the relevance of neighbourhoods as sites of connection, interaction, and social engagement for people living with dementia

    Pro-inflammatory role of monocyte-derived CX3CR1int macrophages in Helicobacter hepaticus-induced colitis

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    Cells of the monocyte-macrophage lineage play important roles in the pathogenesis of inflammatory bowel diseases, but they are also present in the normal healthy intestine, where they are critical for maintaining homeostasis. It has been unclear whether the pro-inflammatory roles of intestinal macrophages reflect altered behaviour of the existing resident cells, or if they involve recruitment of a distinct cell type. Here we have explored these ideas using the model of colitis induced by Helicobacter hepaticus (Hh) in the context of neutralisation or deletion of interleukin 10 (IL-10). Granulocytes and monocytes made up most of the inflammatory myeloid infiltrates found in the colon of Hh-infected colitic mice, rising to a peak within 2 weeks of Hh inoculation, but taking several months to resolve completely. The inflammatory response was dependent on the combined presence of Hh and absence of IL-10, and was accompanied by increased production of inflammatory mediators such as IL-1β, TNFα, IL-6 and IL-23p19 by infiltrating myeloid cells, mostly relatively immature cells of the macrophage lineage that express intermediate levels of CX3CR1. In contrast, the population of mature CX3CR1hi macrophages did not expand as markedly during colitis, and these cells made little contribution to inflammatory mediator production. Taking into account their numerical dominance in the myeloid compartment, we conclude that newly recruited monocytes are the main source of pro-inflammatory mediators in colitis induced in the absence of IL-10 signalling, and that altered behaviour of mature macrophages is not a major component of this pathology

    Brass smelting dust as a source of ZnO in the production of targets used in magnetron sputtering thin film deposition

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    The feasibility of using a zinc oxide rich waste (ZnO>95%), dust originated in the brass smelting industrial process, as a raw material to produce targets to be used in radiofrequency magnetron sputtering (RFMS) deposition of ZnO thin films was investigated. The ZnO waste was characterized in terms of chemical and mineralogical compositions and particle size distribution. The targets were prepared by uniaxial pressing of the ZnO waste followed by sintering in air at a temperature in the range 900-1200 ºC. The density of sintered targets increased with sintering temperature, and zincite (ZnO) was the predominant crystalline phase identified by X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed zincite grains, with an average size ~2 m and a nonhomogeneous microstructure due to the presence of dense aggregates. Preliminary MS thin film deposition tests on a glass substrate produced transparent nanostructured ZnO thin films with a homogeneous microstructure. Research work is underway to process ZnO waste-based targets with an improved microstructure in order to obtain RFMS deposited ZnO thin films with optimized final electrical and optical properties
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