Numerical approximations for a fully fractional Allen-Cahn equation

A finite element scheme for an entirely fractional Allen-Cahn equation with non-smooth initial data is introduced and analyzed. In the proposed nonlocal model, the Caputo fractional in-time derivative and the fractional Laplacian replace the standard local operators. Piecewise linear finite elements and convolution quadratures are the basic tools involved in the presented numerical method. Error analysis and implementation issues are addressed together with the needed results of regularity for the continuous model. Also, the asymptotic behavior of solutions, for a vanishing fractional parameter and usual derivative in time, is discussed within the framework of the Gamma-convergence theory

Final Muon Cooling For A Muon Collider

To explore the new energy frontier, a new generation of particle accelerators is needed. Muon colliders are a promising alternative if muon cooling can be made to work. Muons are 200 times heavier than electrons, so they produce less synchrotron radiation, and they behave like point particles. However, they have a short lifetime of 2.2 μs and the beam is more difficult to cool than an electron beam. The Muon Accelerator Program (MAP) was created to develop concepts and technologies required by a muon collider. An important effort has been made in the program to design and optimize a muon beam cooling system. The goal is to achieve the small beam emittance required by a muon collider. This work explores a final ionization cooling system using magnetic quadrupole lattices with a low enough β* region to cool the beam to the required limit with available low Z absorbers

Regularity theory and high order numerical methods for the (1D)-fractional Laplacian

This paper presents regularity results and associated high-order numerical methods for one-dimensional Fractional-Laplacian boundary-value problems. On the basis of a factorization of solutions as a product of a certain edge-singular weight $w$ times a ``regular´´ unknown, a characterization of the regularity of solutions is obtained in terms of the smoothness of the corresponding right-hand sides. In particular, for right-hand sides which are analytic in a Bernstein Ellipse, analyticity in the same Bernstein Ellipse is obtained for the ``regular´´ unknown. Moreover, a sharp Sobolev regularity result is presented which completely characterizes the co-domain of the Fractional-Laplacian operator in terms of certain weighted Sobolev spaces introduced in (Babu{s}ka and Guo, SIAM J. Numer. Anal. 2002). The present theoretical treatment relies on a full eigendecomposition for a certain weighted integral operator in terms of the Gegenbauer polynomial basis. The proposed Gegenbauer-based Nystr"om numerical method for the Fractional-Laplacian Dirichlet problem, further, is significantly more accurate and efficient than other algorithms considered previously. The sharp error estimates presented in this paper indicate that the proposed algorithm is spectrally accurate, with convergence rates that only depend on the smoothness of the right-hand side. In particular, convergence is exponentially fast (resp. faster than any power of the mesh-size) for analytic (resp. infinitely smooth) right-hand sides. The properties of the algorithm are illustrated with a variety of numerical results.Fil: Acosta, Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; ArgentinaFil: Borthagaray, Juan Pablo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; ArgentinaFil: Bruno, Oscar Ricardo. California Institute Of Technology; Estados UnidosFil: Maas, Martín Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Efficient Approach for OS-CFAR 2D Technique Using Distributive Histograms and Breakdown Point Optimal Concept applied to Acoustic Images

In this work, a new approach to improve the algorithmic efficiency of the Order Statistic-Constant False Alarm Rate (OS-CFAR) applied in two dimensions (2D) is presented. OS-CFAR is widely used in radar technology for detecting moving objects as well as in sonar technology for the relevant areas of segmentation and multi-target detection on the seafloor. OS-CFAR rank orders the samples obtained from a sliding window around a test cell to select a representative sample that is used to calculate an adaptive detection threshold maintaining a false alarm probability. Then, the test cell is evaluated to determine the presence or absence of a target based on the calculated threshold. The rank orders allows that OS-CFAR technique to be more robust in multi-target situations and less sensitive than other methods to the presence of the speckle noise, but requires higher computational effort. This is the bottleneck of the technique. Consequently, the contribution of this work is to improve the OS-CFAR 2D with the distributive histograms and the optimal breakdown point optimal concept, mainly from the standpoint of efficient computation. In this way, the OS-CFAR 2D on-line computation was improved, by means of speeding up the samples sorting problem through the improvement in the calculus of the statistics order. The theoretical algorithm analysis is presented to demonstrate the improvement of this approach. Also, this novel efficient OS-CFAR 2D was contrasted experimentally on acoustic images.Fil: Villar, Sebastian Aldo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Electromecánica. Grupo INTELYMEC; ArgentinaFil: Menna, Bruno Victorio. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Electromecánica. Grupo INTELYMEC; ArgentinaFil: Torcida, Sebastián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; ArgentinaFil: Acosta, Gerardo Gabriel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Electromecánica. Grupo INTELYMEC; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

Liolaemus fitzgeraldi (Fitzgerald’s Tree Iguana): Endoparasites

A total of 158 species of the genus Liolaemus occur in Argentina (Abdala and Quinteros 2014. Cuad. Herpetol. 28:55–82). Liolaemus fitzgeraldi is distributed in Argentina and Chile (Acosta et al. 2017. Los Reptiles de San Juan. Editorial Brujas, Córdoba. 130 pp.). In Argentina, L. fitzgeraldi is distributed in San Juan and Mendoza provinces (Abdala et al. 2012. Cuad. Herpetol. 26:215–248). This small species is predominantly omnivorous and has a unimodal activity pattern (Acosta et al. 2017, op. cit.). According to the latest categorization of lizards of Argentina, it holds a status of insufficiently known (Abdala et al. 2012, op. cit.). The purpose of our note is to provide, for the first time, a record of Parapharyngodon sp. in L. fitzgeraldi. Fourteen specimens of L. fitzgeraldi (seven juveniles: mean SVL = 24.1 ± 0.6 mm, range: 23–25 mm; seven adults: mean SVL = 51.7 ± 4 mm, range: 45–56 mm) were collected (by noosing) in January 2015 from Los Azules, Calingasta Department, Provinces of San Juan, Argentina. For each specimen, the body cavity was opened with a mid-ventral incision, the digestive tract was removed, and its contents examined for helminthes using a dissecting microscope. The nematodes found were stored in 70% ethanol. Nematode observation and identification was done using the diaphanization by lactophenol technique. Seven nematodes (6 females, 1 male) were isolated from the stomachs and identified as Parapharyngodon sp. The specimens were deposited in the parasitological collection of the Department of Biology, National University of San Juan (UNSJPar253). Infection prevalence was 14% with a mean intensity of 3.5 ± 0.7 (range: 3–4). Parasitic nematodes of the genus Parapharyngodon have a direct life cycle, where moisture plays an important role (Castillo et al. 2018. Ann. Parasitol. 64:83–88). Pharyngodonidae includes intestinal parasites of reptiles herbivorous and omnivorous (Anderson 2000. Nematode Parasites of Vertebrates: Their Development and Transmission. CABI Publishing, Oxon, U.K. 650 pp.). Previous reports of Parapharyngodon from Argentina have been documented. In Argentina, Parapharyngodon are parasites of lizards of the families Liolaemidae and Tropiduridae: Phymaturus punae (Ramallo et al. 2002. J. Parisitol. 88:979–982; Ramallo et al. 2016. Acta Parasitol. 61:461–465), P. palluma and Liolaemus buergeri (Goldberg et al. 2004. Comp. Parasitol. 71:208– 204), P. antofagastensis, P. zapalensis, L. rothi, L. boulengeri, and L. umbrifer (O’Grady and Dearing 2006. Oecologia 150:355–361), P. williamsi (Ramallo et al. 2016. Acta Parasitol. 61:461–465), P. extrilidus (Ramallo et al. 2017. Herpetol. Rev. 48:198; Castillo et al. 2018. Ann. Parasitol. 64:83–88), L. ruibali (Castillo et al. 2017. Herpetol. Rev. 48:651–652), Tropidurus torquatus (Lamas and Zaracho 2006. Herpetol. Rev. 37:4), and T. etheridgei (Cruz et al. 1998. Herpetol. Nat. Hist. 6:23–21).Fil: Castillo, Gabriel Natalio. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Acosta, Juan Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Acosta, Rodrigo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentin

Vermicomposta como componente de sustrato en el cultivo de Ageratum houstonianum Mill. y Petunia hybrida E.Vilm. en contenedor

La búsqueda de sustratos alternativos con bajo impacto al medio ambiente se hace indispensable para mantener la producción de cultivos ornamentales de importancia económica. En este trabajo se evaluó el efecto de la vermicomposta como componente de sustrato en los cultivos de Ageratum hustonianum y Petunia hybrida en contenedor. Los tratamientos consistieron en diferentes dosis de vermicomposta combinadas con un sustrato preparado con tierra de bosque, aserrín de pino y fibra de coco, en volúmenes iguales. En general se observaron diferencias significativas por efecto de los tratamientos aplicados en ambos cultivos. En las dos especies, el tratamiento que mostró los mejores resultados para la mayoría de las variables fue la dosis más alta de vermicomposta (100 %). La misma promovió una respuesta mayor en las variables de crecimiento y floración al tratamiento químico, y en las variables de crecimiento de raíz mostraron un comportamiento similar. En las dos especies, los tratamientos menos favorecidos fueron las dosis de 50 y 25 % de vermicomposta, y el testigo, los cuales mostraron valores estadísticos iguales entre ellos en la mayoría de las variables. Los resultados indican que es posible el cultivo de estas ornamentales en contenedor sustituyendo la aplicación de fertilizantes químicos por dosis de vermicomposta manteniendo la calidad de las plantas producidas. Se concluyó que la adición de dosis altas de vermicomposta, e incluso la utilización de vermicomposta al 100% como medio de crecimiento, ofrecen condiciones adecuadas para el cultivo de ambas especies en contenedor

Local and nonlocal energy-based coupling models

In this paper we study two different ways of coupling a local operator with a nonlocal one so that the resulting equation is related to an energy functional. In the first strategy the coupling is given via source terms in the equation, and in the second one a flux condition in the local part appears. For both models we prove existence and uniqueness of a solution that is obtained via direct minimization of the related energy functional. In the second part of this paper we extend these ideas to local/nonlocal elasticity models in which we couple classical local elasticity with nonlocal peridynamics.Fil: Acosta, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santaló". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Matemáticas "Luis A. Santaló"; ArgentinaFil: Bersetche, Francisco. Universidad Tecnica Federico Santa Maria.; ChileFil: Rossi, Julio Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santaló". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Matemáticas "Luis A. Santaló"; Argentin