Delay-Induced Transient Oscillations in a Two-Neuron Network

Finite transmission times between neurons, referred to as delays, may appear in hardware implementation of neural networks. We analyze the dynamics of a two-neuron network in which the delay modifies the transient and not the long-term behavior of the network. We show that the delay causes some trajectories to oscillate transiently before reaching stationary behavior and the duration of these transients increases exponentially with the delay. Such a phenomeno deteriorates network performance

The effects of deformation inertia (kinetic energy) in the orbital and spin evolution of close-in bodies

The purpose of this work is to evaluate the effect of deformation inertia on tide dynamics, particularly within the context of the tide response equations proposed independently by Boué et al. (Celest Mech Dyn Astron 126:31–60, 2016) and Ragazzo and Ruiz (Celest Mech Dyn Astron 128(1):19–59, 2017). The singular limit as the inertia tends to zero is analyzed, and equations for the small inertia regime are proposed. The analysis of Love numbers shows that, independently of the rheology, deformation inertia can be neglected if the tide-forcing frequency is much smaller than the frequency of small oscillations of an ideal body made of a perfect (inviscid) fluid with the same inertial and gravitational properties of the original body. Finally, numerical integration of the full set of equations, which couples tide, spin and orbit, is used to evaluate the effect of inertia on the overall motion. The results are consistent with those obtained from the Love number analysis. The conclusion is that, from the point of view of orbital evolution of celestial bodies, deformation inertia can be safely neglected. (Exceptions may occur when a higher-order harmonic of the tide forcing has a high amplitude.)publishe

Oval Domes. The Case of the Basílica de la Virgen de los Desamparados of Valencia

[EN] The dome of the Basilica de la Virgen de los Desamparados of Valencia is an emblematic example of Valencian baroque architecture and painting. Its shape, oval or elliptical, has been the subject of controversy in various studies. The study of oval domes throughout history is a very interesting field of research because, among other things, the determination of the exact shape is important in order to conclude how it was built. We approach the problem from a new mathematical point of view, calculating the distances between the points that make up the real data cloud and the hypothetical form considered, oval or ellipse. The use of modern graphic surveying techniques, carried out with a 3D laser scanner, and computation with the powerful symbolic and numerical mathematical solver, Mathematica, has allowed us to accurately determine the shape of the dome and determine that its sections are not well-described by ellipses. A better fit is obtained assuming that sections are ovals. The programming and generalization of the mathematical method employed in this work will allow it to be applied to determine the exact geometry of other oval or ellipsoidal vaults.Calvo Roselló, V.; Capilla Tamborero, E.; Navarro Fajardo, JC. (2020). Oval Domes. The Case of the Basílica de la Virgen de los Desamparados of Valencia. Nexus Network Journal. 22(2):393-409. https://doi.org/10.1007/s00004-019-00465-0S393409222Arphe i Villafañe, Juan de. 1585. Tratado De varia conmmensuracion para la Escultura y Architectura. Sevilla: imprenta de Andrea Pescioni i Juan de León.Barrallo J. 2011. Ovals and Ellipses in Architecture. Proceedings of ISAMA 2011, Columbia College, Chicago, Illinois; p. 9–18.Bérchez Gómez, J. 1995. Basílica de Nuestra Señora de los Desamparados (Valencia). In: Monumentos de la Comunidad Valenciana. Catálogo de Monumentos declarados y conjuntos históricos incoados. Tomo X. Valencia. Arquitectura Religiosa. Valencia: Conselleria de Cultura, Educació i Ciència—Generalitat Valenciana, 204–217.Borngässer, B. 1997a. Arquitectura barroca en España y Portugal. In Toman R. (ed.) El barroco. Arquitectura-escultura-pintura. Köln: Könemann, 78–119.Borngässer, B. 1997b. Arquitectura barroca en Francia. In Toman R. (ed.) El barroco. Arquitectura-escultura-pintura. Köln: Könemann, 122–151.Bosch Reig, I., Roig Picazo, P. 1999. El proyecto de restauración arquitectónica de las cúpulas, tambor y linterna de la Basílica de la Virgen de los Desamparados de Valencia. In: Restauración de Pintura Mural aplicada a la Basílica de la Virgen de los Desamparados de Valencia, Roig Picazo, P. y Bosch Reig, I. Valencia: Servicio de Publicaciones de la U.P.V., 21–74.Calvo López, J., Alonso Rodríguez, M.A., Rabasa Díaz, E.; López Mozo, A. 2005. Cantería Renacentista en la Catedral de Murcia. Murcia: Colegio Oficial de Arquitectos.Capilla Tamborero E., Calvo Roselló, V. 2014. Chapter 8: La cúpula interior de la Basílica de la Virgen de los Desamparados de Valencia. Análisis geométrico y matemático. In: J. C. Navarro (ed.) Bóvedas Valencianas. Arquitecturas ideales, reales y virtuales en época medieval y moderna. Valencia: ed. UPV (Scientia), 196–237. ISBN: 978-84-9048-188-2.Connors, J. 1999. Un teorema sacro: San Carlo alle Quattro Fontane. In Il giovane Borromini. Dagli esordi a San Carlo alle Quattro Fontane. Milano: Skira, 459–512.Dotto, E. 2001. Note sulle costruzioni degli ovali a quattro centri. Vecchie e nuove costruzioni dell’ovale. Disegnare Idee Immagini; XII 23: 7–14.Duvernoy, Sylvie. 2015. Baroque Oval Churches: Innovative Geometrical Patterns in Early Modern Sacred Architecture. Nexus Network Journal 17 (2): 425–456.Fernández Gómez M. 1996. La planta oval. Traza y símbolo. Loggia. Arquitectura & Restauración 3: 16–21.García Jara F. 2008. Las cúpulas de la arquitectura religiosa de la provincia de Alicante: del Renacimiento al siglo XIX. Ph.D. Thesis.García Jara F. 2010. La estereotomía de las cúpulas sobre base oval. In: X Congreso Internacional de Expresión Gráfica aplicada a la Edificación, APEGA 2010, Alicante: 767–780.Gentil Baldrich, J. M. 1994. Planta oval y traza elíptica en la arquitectura: Consideraciones geométricas y un ejemplo español. Valladolid.Gentil Baldrich J.M. 1996. La traza oval y la Sala Capitular de la catedral de Sevilla. Una aproximación geométrica. In: J. A. Ruiz de la Rosa et al. Quatro edificios sevillanos. Sevilla: Colegio Oficial de Arquitectos de Andalucía, Demarcación Occidental, 73–147.Gómez-Collado, M.C.; Calvo Roselló, V; Capilla Tamborero, E. 2018. Mathematical modeling of oval arches. A study of the George V and Neuilly Bridges. Journal of Cultural Heritage Vol. 32: 144–155; https://doi.org/10.1016/j.culher.2018.01.012Hatch, John G. 2015. The Science Behind Francesco Borromini’s Divine Geometry. In: Architecture and Mathematics from Antiquity to the Future, eds. Kim Williams and Michael J. Oswald, vol. II, ch. 61, 217–228. Basel: Birkhäuser.Hill, Michael. 2013. Practical and Symbolic Geometry in Borromini’s San Carlo alle Quattro Fontane. Journal of the Society of Architectural Historians 72 (4): 555–583.Huerta Fernández, S. 2002. Informe sobre la estabilidad de la cúpula interior de la Basílica de la Virgen de los Desamparados de Valencia. Valencia. Conselleria Cultura, Educació y Ciència de la Generalitat Valenciana, 20 páginas.Huerta Fernández, S. 2007. Oval domes, geometry and mechanics. Nexus Network Journal 9(2), 211–248.Huerta Fernández, S. 2012a. Análisis estructural de cúpulas tabicadas: la cúpula interior de la Basílica de la Virgen de los Desamparados en Valencia. Construyendo Bóvedas Tabicadas. In: Actas del Simposio Internacional sobre bóvedas tabicadas. Valencia, 26 y 27 de mayo de 2011. Valencia: Editorial Universitat Politècnica de València, 318–335.Huerta Fernández, S. 2012b. Structural Analysis of Thin Tile Vaults and Domes: The Inner Oval Dome of the Basílica de la Virgen de los Desamparados in Valencia. In: Carvais et al (ed.) Nuts and Bolts of construction history. Culture, technology and society. Vol. 1. Paris: Picard, 375–383.Jung, W. 1997.) Arquitectura y ciudad en Italia. In Toman R. (ed.) El barroco. Arquitectura-escultura-pintura. Köln: Könemann, 12–75.Kluckert, E. 1997. Arquitectura barroca en Alemania, Suiza, Austria y Europa oriental. In Toman R. (ed.) El barroco. Arquitectura-escultura-pintura. Köln: Könemann, 184–273.López Manzanares, G. 2005. La contribución de R. G. Boscovich al desarrollo de la teoría de cúpulas: el informe sobre la Biblioteca Cesarea de Viena. In: Huerta, S. (ed.) Actas del Cuarto Congreso Nacional de Historia de la Construcción. Cádiz, 27–29 January 2005. Madrid: Instituto Juan de Herrera, 655–665.López Mozo A. 2011. Ovals for Any Given Proportion in Architecture: A Layout Possibly Known in the Sixteenth Century. Nexus Network Journal Vol. 13: 569–597.Mazzotti, A. 2014a. A Euclidean Approach to Eggs and Polycentric Curves. Nexus Network Journal, 16, 345–387. DOI https://doi.org/10.1007/s00004-014-0189-5Mazzotti, A. 2014b. What Borromini Might Have Known About Ovals. Ruler and Compass Constructions. Nexus Network Journal. https://doi.org/10.1007/s00004-014-0190-z .Mazzotti, A. 2017. All sides to an oval. Properties, Parameters, and Borromini’s Mysterious Construction. Springer. DOI https://doi.org/10.1007/978-3-319-39375-9Montoliu Soler, V. 2012. La Real Capilla de la Virgen de los Desamparados de Valencia: sus orígenes histórico-artísticos. Valencia: Real Academia de Cultura Valenciana.Navascués Palacio, P. 1974. El libro de arquitectura de Hernán Ruiz el Joven. Estudio y edición crítica por Pedro Navascues Palacio. Madrid: Escuela Técnica Superior de Arquitectura.Petrovic, Maja et al. 2019. A Focal Curve Approximation of a Borromini Oval Contour. 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Uncovering genetic and non-genetic biomarkers specific for exudative age-related macular degeneration : significant association of twelve variants

Age-related Macular Degeneration (AMD) represents one of the most sightthreatening diseases in developed countries that substantially impacts the patients' lifestyle by compromising everyday activities, such as reading and driving. In this context, understanding the prevalence, burden, and population-specific risk/ protective factors of AMD is essential for adequate health care planning and provision. Our work aimed to characterize exudative AMD in Italian population and to identify the susceptibility/protective factors (genetic variants, age, sex, smoking and dietary habits) which are specific for the onset of disease. Our study involved a cohort of 1976 subjects, including 976 patients affected with exudative AMD and 1000 control subjects. In particular, the sample cohort has been subjected to a large genotyping analysis of 20 genetic variants which are known to be associated with AMD among European and Asiatic populations. This analysis revealed that 8 genetic variants (CFH, ARMS2, IL-8, TIMP3, SLC16A8, RAD51B, VEGFA and COL8A1) were significantly associated with AMD susceptibility. Successively, we performed a multivariate analysis, considering both genetic and non-genetic data available for our sample cohort. The multivariate analysis showed that age, smoking, dietary habits and sex, together with the genetic variants, were significantly associated with AMD in our population. Altogether, these data represent a starting point for the set-up of adequate preventive and personalized strategies aimed to decrease the burden of disease and improve the patients' quality of life

No evidence of association between prothrombotic gene polymorphisms and the development of acute myocardial infarction at a young age

Background : we investigated the association between 9 polymorphisms of genes encoding hemostasis factors and myocardial infarction in a large sample of young patients chosen because they have less coronary atherosclerosis than older patients, and thus their disease is more likely to be related to a genetic predisposition to a prothrombotic state Methods and Results : this nationwide case-control study involved 1210 patients who had survived a first myocardial infarction at an age of 45 years who underwent coronary arteriography in 125 coronary care units and 1210 healthy subjects matched for age, sex, and geographical origin. None of the 9 polymorphisms of genes encoding proteins involved in coagulation (G-455A -fibrinogen: OR, 1.0; CI, 0.8 to 1.2; G1691A factor V: OR, 1.1; CI, 0.6 to 2.1; G20210A factor II: OR, 1.0; CI, 0.5 to 1.9; and G10976A factor VII: OR, 1.0; CI, 0.8 to 1.3), platelet function (C807T glycoprotein Ia: OR, 1.1; CI, 0.9 to 1.3; and C1565T glycoprotein IIIa: OR, 0.9; CI, 0.8 to 1.2), fibrinolysis (G185T factor XIII: OR, 1.2; CI, 0.9 to 1.6; and 4G/5G plasminogen activator inhibitor type 1: OR, 0.9; CI, 0.7 to 1.2), or homocysteine metabolism (C677T methylenetetrahydrofolate reductase: OR, 0.9; CI, 0.8 to 1.1) were associated with an increased or decreased risk of myocardial infarction Conclusions : this study provides no evidence supporting an association between 9 polymorphisms of genes encoding proteins involved in hemostasis and the occurrence of premature myocardial infarction or protection against it

Giovanni Sacchi. La bottega dei modelli per il design. Catalogo della mostra

La mostra fotografica di cui Dal Falco ha curato l'allestimento e con Antonio Paris e Felice Ragazzo la cura scientifica del catalogo è dedicata al più importante modellista italiano del novecento la cui singolare attività è stata connotata da una grande capacità interpretativa e rigore. La mostra propone una selezione di modelli in legno di cirmolo conservati presso la Collezione Permanente del Design della Triennale di Milano costruiti da Sacchi nell’arco di 50 anni distinti in tre sezioni e organizzati in ordine cronologico. Quest’omaggio al lavoro di Sacchi è anche occasione per riflettere sul significato della creatività e dell’innovazione nel design che da un lato non possono prescindere dalla storia e dall’altro devono confrontarsi con nuove tecnologie quali la prototipazione rapida. Alla mostra hanno aderito le istituzioni: Università La Sapienza di Roma, Dipartimento Itaca - Sezione Arti, Design e Nuove Tecnologie, Collezione permanente del design italiano della Triennale di Milano, Factory LSD Roma Design più II edizione, Corso di Laurea in Disegno Industriale, Rivista diid Disegno Industriale, con il patrocinio della Provincia e del Comune di Roma e dell’Adi Associazione per il Disegno industriale