PVT-Robust CMOS Programmable Chaotic Oscillator: Synchronization of Two 7-Scroll Attractors

Designing chaotic oscillators using complementary metal-oxide-semiconductor (CMOS) integrated circuit technology for generating multi-scroll attractors has been a challenge. That way, we introduce a current-mode piecewise-linear (PWL) function based on CMOS cells that allow programmable generation of 2–7-scroll chaotic attractors. The mathematical model of the chaotic oscillator designed herein has four coefficients and a PWL function, which can be varied to provide a high value of the maximum Lyapunov exponent. The coefficients are implemented electronically by designing operational transconductance amplifiers that allow programmability of their transconductances. Design simulations of the chaotic oscillator are provided for the 0.35μ m CMOS technology. Post-layout and process–voltage–temperature (PVT) variation simulations demonstrate robustness of the multi-scroll chaotic attractors. Finally, we highlight the synchronization of two seven-scroll attractors in a master–slave topology by generalized Hamiltonian forms and observer approach. Simulation results show that the synchronized CMOS chaotic oscillators are robust to PVT variations and are suitable for chaotic secure communication applications.Universidad Autónoma de Tlaxcala CACyPI-UATx-2017Program to Strengthen Quality in Educational Institutions C/PFCE-2016-29MSU0013Y-07-23National Council for Science and Technology 237991 22284

Pathological element-based active device models and their application to symbolic analysis

This paper proposes new pathological element-based active device models which can be used in analysis tasks of linear(ized) analog circuits. Nullators and norators along with the voltage mirror-current mirror (VM-CM) pair (collectively known as pathological elements) are used to model the behavior of active devices in voltage-, current-, and mixed-mode, also considering parasitic elements. Since analog circuits are transformed to nullor-based equivalent circuits or VM-CM pairs or as a combination of both, standard nodal analysis can be used to formulate the admittance matrix. We present a formulation method in order to build the nodal admittance (NA) matrix of nullor-equivalent circuits, where the order of the matrix is given by the number of nodes minus the number of nullors. Since pathological elements are used to model the behavior of active devices, we introduce a more efficient formulation method in order to compute small-signal characteristics of pathological element-based equivalent circuits, where the order of the NA matrix is given by the number of nodes minus the number of pathological elements. Examples are discussed in order to illustrate the potential of the proposed pathological element-based active device models and the new formulation method in performing symbolic analysis of analog circuits. The improved formulation method is compared with traditional formulation methods, showing that the NA matrix is more compact and the generation of nonzero coefficients is reduced. As a consequence, the proposed formulation method is the most efficient one reported so far, since the CPU time and memory consumption is reduced when recursive determinant-expansion techniques are used to solve the NA matrix.Promep-Mexico UATLX-PTC-088Junta de Andalucía TIC-2532Ministerio de Educación y Ciencia TEC2007-67247, TEC2010-14825UC-MEXUS-CONACyT CN-09-31

Complex Hybrid Inflation and Baryogenesis

We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.Comment: 4 RevTex pages, no figures. Changes made in response to referee's comments; matches version published in Phys.Rev.Let

Self-assembly of Fmoc-tetrapeptides based on the RGDS cell adhesion motif

Self-assembly in aqueous solution has been investigated for two Fmoc [Fmoc ¼ N-(fluorenyl)-9-methoxycarbonyl] tetrapeptides comprising the RGDS cell adhesion motif from fibronectin or the scrambled sequence GRDS. The hydrophobic Fmoc unit confers amphiphilicity on the molecules, and introduces aromatic stacking interactions. Circular dichroism and FTIR spectroscopy show that the self-assembly of both peptides at low concentration is dominated by interactions among Fmoc units, although Fmoc-GRDS shows b-sheet features, at lower concentration than Fmoc-RGDS. Fibre X-ray diffraction indicates b-sheet formation by both peptides at sufficiently high concentration. Strong alignment effects are revealed by linear dichroism experiments for Fmoc-GRDS. Cryo-TEM and smallangle X-ray scattering (SAXS) reveal that both samples form fibrils with a diameter of approximately 10 nm. Both Fmoc-tetrapeptides form self-supporting hydrogels at sufficiently high concentration. Dynamic shear rheometry enabled measurements of the moduli for the Fmoc-GRDS hydrogel, however syneresis was observed for the Fmoc-RGDS hydrogel which was significantly less stable to shear. Molecular dynamics computer simulations were carried out considering parallel and antiparallel b-sheet configurations of systems containing 7 and 21 molecules of Fmoc-RGDS or Fmoc-GRDS, the results being analyzed in terms of both intermolecular structural parameters and energy contributions

The Southern Proper Motion Program III. A Near-Complete Catalog to V=17.5

We present the third installment of the Yale/San Juan Southern Proper Motion Catalog, SPM3. Absolute proper motions, positions, and photographic B,V photometry are given for roughly 10.7 million objects, primarily stars, down to a magnitude of V=17.5. The Catalog covers an irregular area of 3700 square degrees, between the declinations of -20 and -45 degrees, excluding the Galactic plane. The proper-motion precision, for well-measured stars, is estimated to be 4.0 mas/yr. Unlike previous releases of the SPM Catalog, the proper motions are on the International Celestial Reference System by way of Hipparcos Catalog stars, and have an estimated systematic uncertainty of 0.4 mas/yr. The SPM3 Catalog is available via electronic transfer,(http://www.astro.yale.edu/astrom/) As an example of the potential of the SPM3 proper motions, we examine the Galactocentric velocities of a group of metal-poor, main-sequence A stars. The majority of these exhibit thick-disk kinematics, lending support to their interpretation as thick-disk blue stragglers, as opposed to being an accreted component.Comment: 23 pages, 10 figures, accepted for publication in Astronomical Journa

Special Issue on Applied Earth Observation and Remote Sensing in Latin America

This special Issue focused on recent research led by South American researchers and teams. It is a long overdue pos- sibility offered to researchers in this geographical area to share their excellent work with the international community. Accord- ingly, the response to the call for papers was overwhelming, with more than 60 papers submitted from eight countries. Eventually, 23 articles were accepted, among which 11 are authored from Brazil, while Argentina and Mexico contribute each with five papers, and Colombia and Ecuador have one arti- cle accepted each. Testifying the international breadth of these researches, seven of these contributions have coauthors from outside Latin America: two from Italy, and one from France, Canada, Finland, USA, and Germany. Before describing the contributions that have been selected for this issue, it is worth recalling briefly the history and current situation of remote sensing activities in the three major countries in the area, which, as mentioned, contribute to the large majority of the works published in the following pages.ITESO, A.C

Space Velocities of Southern Globular Clusters. IV. First Results for Inner-Galaxy Clusters

We have measured the absolute proper motions of four low-latitude, inner-Galaxy globular clusters. These clusters are: NGC 6266 (M62), NGC 6304, NGC 6316 and NGC 6723. The proper motions are on the Hipparcos system, as no background extragalactic objects are found in these high-extinction regions. The proper-motion uncertainties range between 0.3 and 0.6 mas/yr. We discuss the kinematics of these clusters and of three additional bulge clusters -- NGC 6522, NGC 6528 and NFC 6553 -- whose proper motions with respect to bulge stars had been determined previously. We find that all of the clusters have velocities that confine them to the bulge region. Of the three metal poor clusters ([Fe/H] < -1.0), NGC 6522, and NGC 6723 have kinematics consistent with halo membership. The third cluster, NGC 6266 however, appears to belong to a rotationally-supported system. Of the four metal rich clusters ([Fe/H] >= -1.0), NGC 6304 and NGC 6553 also have kinematics consistent with membership to a rotationally-supported system. NGC 6528 has kinematics, metallicity and mass that argue in favor of a genuine Milky-Way bar cluster. NGC 6316's kinematics indicate membership to a hotter system than the bar.Comment: 4 figures, 5 tables; accepted for publication in A

Public Health Considerations for PM₁₀ in a High-Pollution Megacity: Influences of Atmospheric Condition and Land Coverage

Restrictions apply to the availability of these data. Data was obtained from Red de Monitoreo de Calidad del Aire de Bogotá (RMCAB) and are available at http://201.245.192.252:81/Report/stationreport with the permission of RMCAB.[Abstract] This paper analyzes the PM₁₀ concentrations and influences of atmospheric condition (AC) and land coverage (LC) on a high-pollution megacity (Bogota, Colombia) from a public health viewpoint. Information of monitoring stations equipped with measuring devices for PM₁₀/temperature/solar-radiation/wind-speed were used. The research period lasted eight years (2007–2014). AC and LC were determined after comparing daily PM₁₀ concentrations (DPM₁₀) to reference limits published by the World Health Organization (WHO). ARIMA models for DPM₁₀ were also developed. The results indicated that urban sectors with lower atmospheric instability (AI) had a 2.85% increase in daily mortality (DM) in relation to sectors with greater AI. In these sectors of lower AI, impervious LC predominated, instead of vegetated LC. An ARIMA analysis revealed that a greater extent of impervious LC around a station led to a greater effect on previous days’ DPM₁₀ concentrations. Extreme PM₁₀ episodes persisted for up to two days. Extreme pollution episodes were probably also preceded by low mixing-layer heights (between 722–1085 m). The findings showed a 13.0% increase in WHO standard excesses (PE) for each 10 µg/m³ increase in DPM₁₀, and a 0.313% increase in DM for each 10% increase in PE. The observed average reduction of 14.8% in DPM₁₀ (−0.79% in DM) was probably due to 40% restriction of the traffic at peak hours.http://201.245.192.252:81/Report/stationrepor

Finite Element Modeling of Composite Materials using Kinematic Constraints

El propósito de este artículo es presentar simulaciones del comportamiento de materiales compuestos basado en restricciones cinemáticas entre las mismas fibras y entre las fibras y la resina circundante -- En la revisión de literatura, los autores han encontrado que las restricciones cinemáticas no han sido plenamente explotadas para modelar materiales compuestos, probablemente debido a su alto costo computacional -- El propósito de este artículo es exponer la implementación y resultados de tal modelo, usando Análisis por Elementos Finitos de restricciones geométricas prescritas a los nodos de la resina y las fibras -- Las descripciones analíticas del comportamiento de materiales compuestos raramente aparecen -- Muchas aproximaciones para describir materiales compuestos en capas son basadas en la teoría de funciones C1 Z y C0Z, tal como la Teoría Clásica de Capas (CLT) -- Estas teorías de funciones contienen significativas simplificaciones del material, especialmente para compuestos tejidos -- Una aproximación hibrida para modelar materiales compuestos con Elementos Finitos (FEA) fue desarrollada por Sidhu y Averill [1] y adaptada por Li y Sherwood [2] para materiales compuestos tejidos con polipropileno de vidrio -- Este artículo presenta un método para obtener valores para las propiedades de los materiales compuestos -- Tales valores son usados para simular las fibras reforzadas tejidas aplicando elementos de capas en el software ANSYS -- El presente modelo requiere menos simplificaciones que las teorías C1Z y C0Z -- En el artículo presente, a diferencia del modelo Li–Sherwood, el tejido es modelado geométricamente -- Una Representación por la Frontera (B-Rep del modelo “Hand”) con genus 1 (con geometría compleja) fue usada para aplicar restricciones geométricas a las capas de resina, fibra, etcétera, mostrando que es apropiada para simular estructuras complejas -- En el futuro, las propiedades no–lineales de los materiales deben ser consideradas, y el trabajo experimental requerido debe ser realizad