A geometric approach to dense Cayley digraphs of finite Abelian groups

We give a method for constructing infinite families of dense (or eventually likely dense) Cayley digraphs of finite Abelian groups. The diameter of the digraphs is obtained by means of the related minimum distance diagrams. A dilating technique for these diagrams, which can be used for any degree of the digraph, is applied to generate the digraphs of the family. Moreover, two infinite families of digraphs with distinguished metric properties will be given using these methods. The first family contains digraphs with asymptotically large ratio between the order and the diameter as the degree increases (moreover it is the first known asymptotically dense family). The second family, for fixed degree d = 3, contains digraphs with the current best known density.Peer ReviewedPostprint (author's final draft

Abelian Cayley digraphs with asymptotically large order for any given degree

Abelian Cayley digraphs can be constructed by using a generalization to Z(n) of the concept of congruence in Z. Here we use this approach to present a family of such digraphs, which, for every fixed value of the degree, have asymptotically large number of vertices as the diameter increases. Up to now, the best known large dense results were all non-constructive.Peer ReviewedPostprint (author's final draft

Azide-alkyne cycloadditions in a vortex fluidic device: Enhanced "on water" effects and catalysis in flow

The Vortex Fluidic Device is a flow reactor that processes reactions in thin films. Running the metal-free azide-alkyne cycloaddition in this reactor revealed a dramatic enhancement of the "on water"effect. For the copper-catalyzed azide-alkyne cycloaddition, stainless steel or copper jet feeds were effective reservoirs of active copper catalyst.Fil: Oksdath Mansilla, Gabriela. Flinders University.; Australia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Kucera, Renata L.. Flinders University.; AustraliaFil: Chalker, Justin Mark. Flinders University.; AustraliaFil: Raston, Colin Llewellyn. Flinders University.; Australi

Spectral Analysis of Guanine and Cytosine Fluctuations of Mouse Genomic DNA

We study global fluctuations of the guanine and cytosine base content (GC%) in mouse genomic DNA using spectral analyses. Power spectra S(f) of GC% fluctuations in all nineteen autosomal and two sex chromosomes are observed to have the universal functional form S(f) \sim 1/f^alpha (alpha \approx 1) over several orders of magnitude in the frequency range 10^-7< f < 10^-5 cycle/base, corresponding to long-ranging GC% correlations at distances between 100 kb and 10 Mb. S(f) for higher frequencies (f > 10^-5 cycle/base) shows a flattened power-law function with alpha < 1 across all twenty-one chromosomes. The substitution of about 38% interspersed repeats does not affect the functional form of S(f), indicating that these are not predominantly responsible for the long-ranged multi-scale GC% fluctuations in mammalian genomes. Several biological implications of the large-scale GC% fluctuation are discussed, including neutral evolutionary history by DNA duplication, chromosomal bands, spatial distribution of transcription units (genes), replication timing, and recombination hot spots.Comment: 15 pages (figures included), 2 figure

Flujo de diseño asíncrono con la biblioteca DCVSL_LIB para ES2 ECPD10

En el presente trabajo se pretende abordar la metodología a seguir durante el flujo de diseño de un circuito asíncrono orientado a prestaciones, utilizando la biblioteca DCVSL_LIB para aplicaciones asíncronas que hemos desarrollado. Este proceso se aplicará desde un nivel semicustom. La concepción de los algoritmos del sistema se desarrollaran desde una metodología top-down, dadas las restricciones que por construcción debe contener un control asíncrono. Mientras que aspectos tales como el procesado del flujo de datos y control sobre el datapath se aplicaran con una jerarquía botton-up, facilitando la concepción de circuitos asíncronos sencillos y de elevadas prestaciones a partir de soluciones arquitecturales conocidas.Postprint (published version

Comparative study of magnetic properties in central region of Córdoba province, Argentina

En la presente contribución se presentan resultados obtenidos de dos perfiles ubicados en localidades cercanas en la región central de la provincia de Córdoba. El objetivo del estudio fue determinar los parámetros magnéticos de los sedimentos constitutivos de los perfiles a fin de establecer una correlación entre ambos, así como efectuar una valoración de los cambios paleoambientales registrados. Ambos perfiles fueron descriptos y muestreados en detalle; en los especímenes colectados se realizaron mediciones de susceptibilidad magnética a 470 Hz y 4700 Hz, coercitividad, coercitividad de remanencia, magnetización de saturación y magnetización remanente de saturación, S-ratio, magnetización remanente anhistérica y susceptibilidad a altas temperaturas. Los resultados obtenidos permiten inferir que a pesar de encontrarse en una misma región, existen diferencias en la señal magnética, lo cual puede deberse a mayor presencia de carbonatos en uno de los perfiles, mayor retrabajo del material, diferencias en la permeabilidad, o una combinación de todas esas causas.This contribution presents results obtained from two profiles located in nearby towns in the central region of Córdoba province. The objective of the study was to determine the magnetic parameters of the sediments that constitute the profiles in order to establish a correlation between both of them, and to evaluate any record of paleoenvironmental changes. The profiles were described and sampled in detail; in the collected specimens magnetic susceptibility at 470 Hz and 4700 Hz was measured, as well as coercivity, coercivity of remanence, saturation magnetization and remanent saturation magnetization, S-ratio, anhysteric remanent magnetization and susceptibility at high temperatures. From the obtained results it is possible to infer that despite the proximity of the profiles, there are differences in their magnetic signal, which may be due to a higher content of carbonates in one of the profiles, more remobilization of the material, permeability differences, or a combination of all these causes.Fil: Rouzaut, Sabrina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Orgeira, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Tofalo, Ofelia Rita de Las Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos ; ArgentinaFil: Vasquez, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Argüello, G. L.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Sanabria, J.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Mansilla, L.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentin

Protective films on complex substrates of thermoplastic and cellular elastomers:Prospective applications to rubber, nylon and cork

Deposition of thin films is an appropriate methodology to enhance the performance of a material by modification of its surface, while keeping the properties of the bulk largely unaffected. However, a practical implementation becomes less straightforward when dealing with sensitive or complex substrates, for instance, those which cannot be subjected to harsh treatments, such as cleaning and etching, or extreme deposition conditions, like high temperatures, and ion impingement et cetera. This paper concentrates on deposition processing of complex substrates. In particular, it discusses the deposition of two types of protective coatings (diamond-like carbon (DLC) films against friction and wear, and TiO2 films against UV light) on three types of thermoplastic and cellular elastomers (rubber, nylon and cork). It is demonstrated that a successful protection of thermoplastic elastomers against wear with DLC films can be attained, after a thorough adaptation of the procedure to the characteristics of the specific substrate. In addition, the paper reports the very first depositions on a cellular elastomer like cork by vapor deposition methods, including Atomic Layer Deposition (ALD)

Effect of temperature and copper doping on the heterogeneous Fenton-like activity of Cux_xFe3−x_{3-x}O4_4 nanoparticles

Ferrite nanoparticles serve as potent heterogeneous Fenton-like catalysts, producing reactive oxygen species (ROS) for decomposing organic pollutants. We investigated the impact of temperature and copper content on the catalytic activity of nanoparticles with different oxidation states of iron. Via solvothermal synthesis, we fabricated copper-doped magnetite (Cu$_x$Fe$_{3-x}$O$_4$) with a Fe$^{2+}$/Fe ratio ~0.33 for the undoped system. Using a microwave-assisted method, we produced copper-doped oxidized ferrites, yielding a Fe$^{2+}$/Fe ratio of ~0.11 for the undoped nanoparticles. The ROS generated by the catalyst were identified and quantified by electron paramagnetic resonance, while optical spectroscopy allowed us to evaluate its effectiveness for the degradation of a model organic dye. At room temperature, the magnetite nanoparticles exhibited the most $\cdot$OH radical production and achieved almost 90% dye discoloration in 2 hours. This efficiency decreased with increasing Cu concentration, concurrently with a decrease in $\cdot$OH generation. Conversely, above room temperature, Cu-doped nanoparticles significantly enhance the dye degradation, reaching 100% discoloration at 90$^\circ$C. This enhancement is accompanied by a systematic increase in the kinetic constants, obtained from reaction equations, with Cu doping. This study highlights the superior stability and high-temperature catalytic advantages of copper ferrite holding promise for enhancing the performance of nanocatalysts for decomposing organic contaminants.Comment: 40 pages, 11 figure