722 research outputs found

    A logical study of local and global graded similarities

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    In this work we study the relationship between global and local similarities in the graded framework of fuzzy class theory (FCT), in which there already exists a graded notion of similarity. In FCT we can express the fact that a fuzzy relation is reflexive, symmetric, or transitive up to a certain degree, and similarity is defined as a first-order sentence, which is the fusion of three sentences corresponding to the graded notions of reflexivity, symmetry, and transitivity. This allows us to speak in a natural way of the degree of similarity of a relation. We consider global similarities defined from local similarities using t-norms as aggregation operators, and we obtain some results in the framework of FCT that, adequately interpreted, allow us to say that when we take a t-norm as an aggregation operator, the properties of reflexivity, symmetry, and transitivity of fuzzy binary relations are inherited from the local to the global level, and that the global similarity is a congruence if some of the local similarities are congruence

    Some results on homoclinic and heteroclinic connections in planar systems

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    Consider a family of planar systems depending on two parameters (n,b)(n,b) and having at most one limit cycle. Assume that the limit cycle disappears at some homoclinic (or heteroclinic) connection when Φ(n,b)=0.\Phi(n,b)=0. We present a method that allows to obtain a sequence of explicit algebraic lower and upper bounds for the bifurcation set Φ(n,b)=0.{\Phi(n,b)=0}. The method is applied to two quadratic families, one of them is the well-known Bogdanov-Takens system. One of the results that we obtain for this system is the bifurcation curve for small values of nn, given by b=57n1/2+72/2401n30024/45294865n3/22352961656/11108339166925n2+O(n5/2)b=\frac5 7 n^{1/2}+{72/2401}n- {30024/45294865}n^{3/2}- {2352961656/11108339166925} n^2+O(n^{5/2}). We obtain the new three terms from purely algebraic calculations, without evaluating Melnikov functions

    Innovación y virtualización progresivas de las universidades iberoamericanas hacia la sociedad del conocimiento

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    In any society developed or underdeveloped the key factor for its progress would be its possibility for generating and applying knowledge in the social, technical and cientific areas. For attaining the goal of the complex process of transformation and modernization of such societies the main instrument would be education, specially at the university level, but redesigned in new ways. This paper examines how progressive virtualization and innovation of higher education institutions could play a significant role in that transformation.En cualquier sociedad, sea ella “desarrollada” o “en desarrollo”, el factor clave para su progreso es su efectiva capacidad para generar, y aplicar continuamente el “Conocimiento” a los diversos campos de la vida social, técnica y científica. En consecuencia, el instrumento principal y esencial para los complejos procesos de transformación y modernización de estas sociedades es la educación y dentro de ella especialmente la universitaria. Pero no se trata de la educación y la universidad en sus formas usuales y tradicionales, sino de todo un repensar en formas nuevas de organización, administración, investigación y acción. Estos cambios pueden impulsarse mediante teorías y procesos innovadores que permiten las nuevas tecnologías de la información y comunicación. En este trabajo se examina esta transformación de universidades en base a la tríada de la innovación, virtualización y globalización

    De Vancouver (1982) a Viena (1999): la educación a distancia toma nuevos rumbos

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    The analysis and comparison between the papers and tendencies presented on the two ICDE Conferences of Vancouver (1982) and Vienna (1999), had made possible visualize the vigorous development and important changes of Distance Education during these seventeenth (17) years. Vienna (1999) debated the advances of some fundamental themes presented at Vancouver (1982), but in addition, also some new themes as: Globalization; Policies for Development; Virtual Learning and Virtual Universities, Developing the Company and Workforce Training of the Future, and Markets and marketing. The huge world expansion of Distance Education and the diversity of new technologies available for education, make now indispensable that existing Distance Universities or projected ones, adopt very creative structures and focus, that make possible a great flexibility and capacity to answer rapidly to this new demands and also, to make a better use of modern instruments and technologies.El análisis y comparación entre los trabajos y tendencias presentadas en las Conferencias de ICDE, Vancouver (1982) y Viena (1999) permiten observar aquí el vigoroso desarrollo y cambios de la Educación a Distancia, durante los últimos diecisiete (17) años del final de este Siglo XX. Viena (1999) discutió los avances sobre temas fundamentales presentados en Vancouver (1982), pero también, nuevos Temas tales como: Globalización; Políticas para el Desarrollo; Aprendizaje Virtual y Universidades Virtuales; Entrenamiento para el Trabajo y la Producción; y, Mercados y Mercadeo. La enorme expansión Mundial de la Educación a Distancia y la gran diversidad de Nuevas Tecnologías, hacen ahora imperativo que las Universidades a Distancia existentes ó por crearse, adopten estructuras y enfoques muy creativos, que les permitan una gran flexibilidad y capacidad para responder rápidamente a nuevas demandas y al mejor uso de modernos instrumentos y técnicas

    Myopia control with a novel peripheral gradient soft lens and orthokeratology: a 2-year clinical trial

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    Objective. To evaluate the degree of axial elongation with soft radial refractive gradient (SRRG) contact lenses, orthokeratology (OK), and single vision (SV) spectacle lenses (control) during a period of 1 year before treatment and 2 years after treatment. Methods. This was a prospective, longitudinal, nonrandomized study. The study groups consisted of 30, 29, and 41 children, respectively. The axial length (AL) was measured during 2 years after recruitment and lens fitting. Results. The baseline refractive sphere was correlated significantly (r 2 = 0.542; P < 0.0001) with the amount of myopia progression before baseline. After 2 years, the mean myopia progression values for the SRRG, OK, and SV groups were −0.56 ± 0.51, −0.32 ± 0.53, and −0.98 ± 0.58 diopter, respectively. The results represent reductions in myopic progression of 43% and 67% for the SRRG and OK groups, respectively, compared to the SV group. The AL increased more in the SV group compared to the SRRG and OK groups, with 27% and 38% lower axial elongation, respectively, compared to the SV group at the 2-year visit (P < 0.05). SRRG and OK showed no differences (P = 0.430). Conclusion. The SRRG lens significantly decreased AL elongation compared to the SV control group. The SRRG lens was similarly effective to OK in preventing myopia progression in myopic children and adolescent.This work was funded in part by Fundac¸ao para Ci ˜ encia ˆ e Tecnologia, Lisbon, Portugal (Projects: PTDC/SAUBEB/098392/2008 and PTDC/SAU-BEB/098391/2008)

    Plant sources of galanthamine: phytochemical and biotechnological aspects.

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    Galanthamine, an Amaryllidaceae type alkaloid, is an AChE inhibitor marketed as a hydrobromide salt for the treatment of Alzheimer's disease, poliomyelitis and other neurological diseases. Although the chemical synthesis of galanthamine has been successfully performed, plants are the main source of its production. The phytochemical and biotechnological aspects of plants currently used for galanthamine production, namely Leucojum aestivum, Narcissus ssp. Ungernia victoris and Lycoris radiata, are summarized in the present paper

    Cross pathogenicity of Neofusicoccum australe and Neofusicoccum stellenboschiana on grapevine and selected fruit and ornamental trees

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    [EN] Neofusicoccum australe is one of the most important Botryosphaeriaceae pathogens occurring on fruit and vine crops. This fungus was recently taxonomically reassessed, identifying N. stellenboschiana as a separate species. Previous pathogenicity studies used N. stellenboschiana and N. australe isolates as N. australe, so assessment of the pathogenicity of these two species on grapevine and other hosts was required. A pathogenicity trial was conducted on detached shoots of grapevine, plum, apple, olive and Peruvian pepper tree. Shoots were individually inoculated with 11 N. australe and eight N. stellenboschiana isolates originally isolated from grapevine, plum, apple, olive, Peruvian pepper and fig. Both species formed lesions on all five hosts and were reisolated 5 weeks post-inoculation. In general, the largest lesions were formed on plum and smallest on Peruvian pepper. Isolate host origin did not influence ability to cause lesions on other hosts. Isolates of N. australe and N. stellenboschiana differed in virulence on the various hosts, ranging from those that caused the largest lesions, a group causing intermediate lesions, and another causing lesions similar to uninoculated controls. The study demonstrates that N. australe and N. stellenboschiana isolates originating from various fruit hosts can infect alternative hosts including grapevine and other major fruit crops.This research developed from a mobility sojourn funded by the Erasmus Mundus Joint Master Degrees Programme of the European Commission under the PLANT HEALTH Project. The authors also acknowledge financial support from ARC Infruitec-Nietvoorbij and the National Research Foundation of South Africa (NRF UID88771). Technical Assistance was provided by Carine Vermeulen, Danie Marais, Julia Marais, Muriel Knipe, Lydia Maart, Christopher Paulse, Bongiwe Sokwaliwa, Nadeen van Kervel, and Levocia Williams (Plant Protection Division, ARC Infruitec-Nietvoorbij).Mojeremane, K.; Lebenya, P.; Du Plessis, IL.; Van Der Rijst, M.; Mostert, L.; Armengol Fortí, J.; Halleen, F. (2020). Cross pathogenicity of Neofusicoccum australe and Neofusicoccum stellenboschiana on grapevine and selected fruit and ornamental trees. PHYTOPATHOLOGIA MEDITERRANEA. 59(3):581-593. https://doi.org/10.14601/Phyto-11609S58159359

    MLIP genotype as a predictor of pharmacological response in primary open-angle glaucoma and ocular hypertension.

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    Predicting the therapeutic response to ocular hypotensive drugs is crucial for the clinical treatment and management of glaucoma. Our aim was to identify a possible genetic contribution to the response to current pharmacological treatments of choice in a white Mediterranean population with primary open-angle glaucoma (POAG) or ocular hypertension (OH). We conducted a prospective, controlled, randomized, partial crossover study that included 151 patients of both genders, aged 18 years and older, diagnosed with and requiring pharmacological treatment for POAG or OH in one or both eyes. We sought to identify copy number variants (CNVs) associated with differences in pharmacological response, using a DNA pooling strategy of carefully phenotyped treatment responders and non-responders, treated for a minimum of 6 weeks with a beta-blocker (timolol maleate) and/or prostaglandin analog (latanoprost). Diurnal intraocular pressure reduction and comparative genome wide CNVs were analyzed. Our finding that copy number alleles of an intronic portion of the MLIP gene is a predictor of pharmacological response to beta blockers and prostaglandin analogs could be used as a biomarker to guide first-tier POAG and OH treatment. Our finding improves understanding of the genetic factors modulating pharmacological response in POAG and OH, and represents an important contribution to the establishment of a personalized approach to the treatment of glaucoma

    X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation

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    Contiene 3 ficheros adicionales con información suplementaria.-- et al.[Background] Aproximately 5–10% of cases of mental retardation in males are due to copy number variations (CNV) on the X chromosome. Novel technologies, such as array comparative genomic hybridization (aCGH), may help to uncover cryptic rearrangements in X-linked mental retardation (XLMR) patients. We have constructed an X-chromosome tiling path array using bacterial artificial chromosomes (BACs) and validated it using samples with cytogenetically defined copy number changes. We have studied 54 patients with idiopathic mental retardation and 20 controls subjects.[Results] Known genomic aberrations were reliably detected on the array and eight novel submicroscopic imbalances, likely causative for the mental retardation (MR) phenotype, were detected. Putatively pathogenic rearrangements included three deletions and five duplications (ranging between 82 kb to one Mb), all but two affecting genes previously known to be responsible for XLMR. Additionally, we describe different CNV regions with significant different frequencies in XLMR and control subjects (44% vs. 20%).[Conclusion] This tiling path array of the human X chromosome has proven successful for the detection and characterization of known rearrangements and novel CNVs in XLMR patients.The authors thank the "Genoma España" and Genome Canada joint R+D+I projects in human health, plants and aquiculture; the former "Departament d'Universitats i Societat de la Informació" (DURSI) and the "Departament de Salut", from the Catalan Autonomous Government (2005SGR00008 - Generalitat de Catalunya); the Instituto de Salud Carlos III (PI041126, CIBER-ESP), the EU's Sixth Framework Programme [FP6-2005-LIFESCIHEALTH-7; ANEUPLOIDY No. 037627] and Fundación Areces (U-2006-FARECES-O).Peer reviewe
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