930 research outputs found

    Achievable bisimilar behaviour of abstract state systems

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    Given a plant system and a desired system, we study conditions for which there exists a controller that interconnected with the plant, yields a system that is bisimilar to the desired system. Some sufficient and some necessary conditions are provided in the general case of (non-deterministic) abstract state systems and stronger results are obtained for the special classes of autonomous abstract state systems, finite abstract state systems, and non-deterministic linear dynamical systems

    Bisimulation theory for switching linear systems

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    A general notion of hybrid bisimulation is proposed and related to the notions of algebraic, state-space and input-output equivalences for the class of switching linear systems. An algebraic characterization of hybrid bisimulations and a procedure converging in a finite number of steps to the maximal hybrid bisimulation are derived. Bisimulation-based reduction and simulation-based abstraction are defined and characterized. Connections with observability are investigated

    Vortex-Bright Soliton Dipoles: Bifurcations, Symmetry Breaking and Soliton Tunneling in a Vortex-Induced Double Well

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    The emergence of vortex-bright soliton dipoles in two-component Bose-Einstein condensates through bifurcations from suitable eigenstates of the underlying linear system is examined. These dipoles can have their bright solitary structures be in phase (symmetric) or out of phase (anti-symmetric). The dynamical robustness of each of these two possibilities is considered and the out-of-phase case is found to exhibit an intriguing symmetry-breaking instability that can in turn lead to tunneling of the bright wavefunction between the two vortex "wells". We interpret this phenomenon by virtue of a vortex-induced double well system, whose spontaneous symmetry breaking leads to asymmetric vortex-bright dipoles, in addition to the symmetric and anti-symmetric ones. The theoretical prediction of these states is corroborated by detailed numerical computations.Comment: 14 pages, 8 figure

    The Meaning of Money and Possessions: A Cross-University Comparison

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    The purpose of the paper is to examine whether students attending state universities and Jesuit universities possess different levels of love of money and materialism. Students attending marketing classes at two universities in the same region of the U.S. (one state and one Jesuit) were asked to complete a survey containing instruments to measure their love of money and their materialism. The results suggest business students attending a Jesuit university have lesser love of money than those attending a state university, but higher materialistic envy

    Efecto de la fase fenológica de verano sobre algunas características del ensamble de Diptera registrado en una vega altoandina del desierto transicional de Chile

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    Diptera are one of the dominant taxonomic groups of animal invertebrates to be found in the highland wet pastures of the transitional desert of Chile. In wetlands, these insects play important roles as pollinators, decomposers and trophic resources for aquatic vertebrates. Additionally, Diptera are recognized to have the potentiality to be used as indicators of the health condition of wet terrestrial environments, important attribute in the case of Andean highland wet pastures given the water stress under which they are presently subjected. By using Barber and Malaise traps, the Diptera-assemblage associated to a highland wet pasture located in a transitional desert basin was investigated. This study was conducted during the growing season for the area. Its aims were to a) document the taxonomic structure of the assemblage in terms of the composition of Diptera-families and the relative abundance of its members, and b) evaluate the effect of the summer phenological phase on F-richness, relative abundance relationships, F-diversity and evenness. The PERMANOVA and t-pairwise tests were used to evaluate the effect of the summer phenological phase on the numerical relationships among families. The Simpsons D, Brillouin D, Berger-Parker dominance, and Fisher indices were used to estimate the F-diversity; in turn, the Simpson E, Camargo, Smith-Wilson B, and NHC indices estimated the F-evenness. Similarity between assemblages was compared by ANOSIM. The percent contribution by family to the observed differences between assemblages was computed by the SIMPER-routine. All analyses were done on the log-transformed data (x+1; log 10). 44524 Diptera-representatives were collected throughout the study, with a record of 27 families. The tests and the indices support the idea that the middle-summer phase provided the best environmental conditions for the diptero-fauna of the wet pasture. Apparently, this effect would be more related to the thermal pattern of the area than to the micro-habitat availabilityEsta publicación fue financiada por la Dirección de Investigación de la Universidad de La Seren

    Showrooming: The Effect of Gender

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    Revisión del género indopacífico Nembrotha Bergh, 1877 (Mollusca: Nudibranchia: Polyceridae), con la descripción de dos nuevas especies

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    Anatomical examination of new material collected from the Indo-Pacific and the review of several collections from around the world allows for the revision of the genus Nembrotha Bergh, 1877. Two new species, Nembrotha rosannulata n. sp. and Nembrotha aurea n. sp., are described. The oldest available name for the genus is Nembrotha nigerrima Bergh, 1877, which was subsequently designated as the type species by O’Donoghue, 1924. The study of the original type material of N. nigerrima confirmed that it is a senior synonym of another name introduced subsequently, Nembrotha kubaryana Bergh, 1877, the name most commonly used for this species. However, according to the provisions of the International Code of Zoological Nomenclature (Article 23.9.1), there is no reason to invalidate the senior name Nembrotha nigerrima, since it has been used as valid after 1899. Nembrotha cristata Bergh, 1877, N. lineolata Bergh, 1905, N. purpureolineata O’Donoghue, 1924, N. livingstonei Allan, 1933, N. megalocera Yonow, 1990 and N. guttata Yonow, 1993, which are poorly known, are redescribed. Nembrotha rutilans (Pruvot-Fol, 1931) is synonymised with N. purpureolineata. Nembrotha yonowae Goethel and Debelius, 1992 is synonymised with N. guttata. The radulae of Nembrotha milleri Gosliner and Behrens, 1997 and N. mullineri Gosliner and Behrens, 1997 are redescribed.El estudio anatómico de nuevo material procedente del Indo-Pacífico así como el examen de diferentes colecciones de todo el mundo ha permitido la revisión del género Nembrotha Bergh, 1877. Se describen dos nuevas especies, Nembrotha rosannulata n. sp. y Nembrotha aurea n. sp. El nombre disponible más antiguo relativo a este género es Nembrotha nigerrima Bergh, 1877, que fue designado subsiguientemente como especie tipo por O’Donoghue, 1924. El estudio del material tipo original de N. nigerrima confirmó que se trata de un sinónimo más antiguo de otro nombre introducido con posterioridad, Nembrotha kubaryana Bergh, 1877, el nombre usado más comúnmente para esta especie. Sin embargo, según lo previsto en el Código Internacional de Nomenclatura Zoológica (Artículo 23.9.1), no hay razón alguna para invalidar el sinónimo más antiguo, Nembrotha nigerrima, ya que este nombre ha sido utilizado como válido después de 1899. Nembrotha cristata Bergh, 1877, N. lineolata Bergh, 1905, N. purpureolineata O’Donoghue, 1924, N. livingstonei Allan, 1933, N. megalocera Yonow, 1990 and N. guttata Yonow, 1993, especies pobremente conocidas, son redescritas. Nembrotha rutilans (Pruvot-Fol, 1931) es sinonimizada con N. purpureolineata. N. Nembrotha yonowae Goethel and Debelius, 1992 es sinonimizada con N. guttata. Se redescriben las rádulas de Nembrotha milleri Gosliner and Behrens, 1997 and N. mullineri Gosliner and Behrens, 1997

    Photo-oxidative action in cervix carcinoma cells induced by HpD — mediated photodynamic therapy

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    Photodynamic therapy leads to oxidative stress through the generation of free radicals. Oxidative stress causes damage to cellular macromolecules such as nucleic acids, proteins and lipids. Aim: To examine the hematoporphyrin derivative (HpD) — mediated photodynamic effect on cervical adenocarcinoma cell line HeLa. Methods: The HpD localization in HeLa cells was analyzed by confocal microscopy with epi-fluorescence system. Lipid peroxidation (LPO) was estimated by measurement of the concentration of malondialdehyde, protein degradation — by modified Ellman’s method, superoxide dysmutase (SOD) — using Ransod Kit. The expression of inducible nitric oxide synthase (iNOS) was detected by immunocytochemical staining. Results: The HpD was distributed all over the cytoplasm with preferential localization in the inner side of the plasma membrane and around the nuclear envelope. The process of photosensitizer distribution was time dependent. PDT-HpD increased the level of malonodialdehyde (MDA), SOD activity and the expression of iNOS in HeLa cells. However, PDT induced the decrease in the level of protein-associated thiol groups. Conclusions: Our study showed the important role of PDT-mediated oxidative stress in HeLa cells. HpD-PDT might be alternative and less invasive approach for treatment of patients with cervical cancer resistant for standard chemotherapy and radiotherapy

    Bisimulation Theory for Switching Linear Systems

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    Achievable Bisimilar Behaviour of Abstract State Systems

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