Formación en Cinemática y Dinámica de Sistemas Multicuerpo Mediante Coordenadas Naturales

La formación de los futuros ingenieros mecánicos en dinámica de sistemas multicuerpo 3-D rara vez encuentra una materia específica en los planes de estudio, ni siquiera en postgrado. Cuando sólo se dispone de algunas horas (entre 5 y 10 horas de clase y unas 15 de trabajo personal) en el marco de una materia más general, las coordenadas naturales y Matlab son probablemente el único camino para alcanzar ciertos objetivos prácticos. Aquí se aborda cómo se pueden alcanzar estos objetivos, con un aprendizaje basado en .casos reales. Very often, the curriculum of mechanical engineers doesn't include any specific subject on kinematics and dynamics of multibody systems. In these situations the unique opportunity to introduce MBS is to dedicate from 5 to 10 hours to this subject inside a more general course, plus about 15 hours of personal work. This paper shows how this short time can be enough if natural coordinates are used. Keywords

FreeWall-1: un cortafuegos corporativo para plataformas Win32

FreeWall-1 es el proyecto para construir un cortafuegos corporativo para plataformas Win32 similar a los cortafuegos comerciales existentes tipo FireWall-1 de CheckPoint o StoneGate de StoneSoft. FreeWall-1 pretende ser una alternativa robusta, fiable y gratuita. FreeWall-1 no pretende ser una copia de un producto comercial, sino que incorporará tecnologías únicas como un IPS (Intrusion Prevention System) en el propio filtrado del cortafuegos. Este IPS en un principio estará basado en reglas de nuestra propia creación o compatibilidad con algunas reglas del IDS SNORT. En un principio dado los recursos humanos (3 personas) y de tiempo (9 meses) que se dispondrán no se incorporará soporte VPN (Virtual Private network), servidores seguros, ni balanceo de carga. Pero se dejará una interfaz para su fácil inclusión posterior. [ABSTRACT] FreeWall-1 is the project to build a corporative firewall for Win32 platform similar to the commercial existing ones such as FireWall-1 of Checkpoint or StoneGate of StoneSoft. FreeWall-1 aims to be a robust alternative, reliable and free. FreeWall-1 objectives are not to be a copy of a commercial product, it will have unique technologies such as an IPS (Intrusion Prevention System) in the filtering stage of the firewall. This IPS in a first stage will be rule based compatible with IDS SNORT rules. Due to limited human (3 people) and time resources (9 months) we will face, FreeWall-1 will not support technologies such as VPN (Virtual Private Network), secure servers nor load balancing. But there will be a clean interface for easy future development

Conferencia del Excmo. Sr. D. Javier Gómez de la Serna pronunciada en la sesión pública de 19 de enero de 1916

Tema: Derecho municipalCopia Digital : Real Academia de Jurisprudencia y Legislación, 2011Precede al tít.: Real Academia de Jurisprudencia y Legislació

Effects of Dielectric Stoichiometry on the Photoluminescence Properties of Encapsulated WSe2 Monolayers

Two-dimensional transition-metal-dichalcogenide semiconductors have emerged as promising candidates for optoelectronic devices with unprecedented properties and ultra-compact performances. However atomically thin materials are highly sensitive to surrounding dielectric media, which imposes severe limitations to their practical applicability. Hence for their suitable integration into devices, the development of reliable encapsulation procedures that preserve their physical properties are required. Here, the excitonic photoluminescence of WSe2 monolayer flakes is assessed, at room temperature and 10 K, on mechanically exfoliated flakes encapsulated with SiOx and AlxOy layers employing chemical and physical deposition techniques. Conformal flakes coating on untreated - non-functionalized - flakes is successfully demonstrated by all the techniques except for atomic layer deposition, where a cluster-like oxide coating is observed. No significant compositional or strain state changes in the flakes are detected upon encapsulation by any of the techniques. Remarkably, our results evidence that the flakes' optical emission is strongly influenced by the quality of the encapsulating oxide - stoichiometry -. When the encapsulation is carried out with slightly sub-stoichiometric oxides two remarkable phenomena are observed. First, there is a clear electrical doping of the monolayers that is revealed through a dominant trion - charged exciton - room-temperature photoluminescence. Second, a strong decrease of the monolayers optical emission is measured attributed to non-radiative recombination processes and/or carriers transfer from the flake to the oxide. Power- and temperature-dependent photoluminescence measurements further confirm that stoichiometric oxides obtained by physical deposition lead to a successful encapsulation.Comment: 30 pages, 6 figure

Optically active Er–Yb doped glass films prepared by pulsed laser deposition

3 pages, 2 figures.Active rare-earth Er3 + –Yb3 + co-doped phosphate glass films are produced in a single step by pulsed laser deposition. The films are multimode waveguides and exhibit the highest refractive index, optical density and 1.54 µm photoluminescence intensity and lifetime when deposited at low oxygen pressure (Pox4 (menor o igual) 10–5 Torr). The density of the films obtained under these conditions is higher than that of the target material as a consequence of the high kinetic energy of the species generated during ablation. Luminescent emission can be excited by optical pumping the Er3 + ions either directly or through cross-relaxation of the Yb3 + . Post-deposition annealing allows us to improve the luminescence performance.This work has been partially supported by CICYT (Spain) under Project No. TIC96-0467. One of the authors (J.M.B.) acknowledges financial support from the Spanish Ministry of Education.Peer reviewe

Gold clusters immobilized by post-synthesis methods on thiol-containing SBA-15 mesoporous materials for the aerobic oxidation of cyclohexene: influence of light and hydroperoxide

Gold nanospecies produced by a historically inspired two-liquid phase system were immobilized on plate-like mesoporous silica, SBA-15, functionalized with mercaptopropyl groups by a post-synthesis method, and the resulting materials were tested in the oxidation of cyclohexene with molecular oxygen at atmospheric pressure. The main purpose of this approach was to compare the physicochemical properties and catalytic performance of these materials with those of previously reported related materials functionalized by in situ methods during synthesis. In addition, catalytic tests under ambient lighting and darkness and also in the presence and absence of the initiator tert-butyl hydroperoxide (TBHP) were carried out. The samples were characterized by chemical analysis, N2 adsorption/desorption, TGA, SEM, HRTEM, UV-vis spectroscopy and XPS. Gold nanoclusters and isolated gold atoms but no AuNPs were found in the catalysts (0.31–2.69 wt.% of gold). The XPS shows that nearly 60% of the -SH groups (1.33 wt.% of S) were oxidized to sulphonic groups upon gold immobilization. The AuNCs and isolated gold atoms evolved in the the reaction medium to form AuNPs. The activity of the samples was lower than that of the catalysts supported on related S-bearing SBA-15 functionalized in situ, which was attributed to their different Au/S ratios, which in turn regulated the evolutionary process of the gold species during the reaction. The catalysts turned out to be inactive in darkness, which evidences that the cyclohexene oxidation carried out at ambient illumination is actually photocatalyzed by the AuNPs formed in situ during the reaction. The TBHP initiator is required to obtain the activity in order to counteract the inhibitors of cyclohexene auto-oxidation present in the commercial reagent. On the other hand, no major differences in the selectivity among the different catalysts and reactions were observed, with 2-cyclohexen-1-one and 2-cyclohexen-1-ol resulting from the allylic oxidation as main products (selectivity of (one + ol) ~80% at a conversion ≥ 35%; one/ol~2)

Amplificación cruzada de microsatélites en el género Centaurea (Compositae).

11p. Fotog. en color. Tablas.[EN] Microsatellites are widely used for population genetic studies although the development of these species-specific markers is costly and time-consuming. One strategy for saving time and money is the use of markers developed for one species (source species) in a different species (target species). This is known as cross-amplification. In the present work, two sets of microsatellites are used to test their transferability to six narrow endemic Centaurea species: i) 16 nuclear loci previously published for three congeneric species and ii) 10 universal chloroplast markers designed from Nicotiana tabacum sequences. Seventeen of the 26 markers tested were transferable and 14 of them were also polymorphic and therefore useful for future works. Nuclear markers were more variable and thus more informative than chloroplast markers. Interspecific amplification performed better for the nuclear loci developed for different Centaurea species than for the universal chloroplast markers developed for Nicotiana tabacum. Likewise, transferability was more successful for the species from sect. Phalolepis than for sect. Lepteranthus. Therefore, our results support the idea that the success of the cross-amplification is influenced by the evolutionary distance between the target and the source species.[ES] Los microsatélites se usan habitualmente en estudios de genética de poblaciones aunque su desarrollo es un proceso caro y largo dada su elevada especificidad. Una estrategia que permite ahorrar tiempo y dinero es la llamada amplificación cruzada que consiste en amplificar el DNA de una especie determinada (especie objetivo) usando marcadores que han sido diseñados para una especie diferente (especie fuente). En este trabajo se ha realizado un ensayo sobre amplificación cruzada usando seis endemismos del género Centaurea y dos conjuntos de microsatélites: i) 16 marcadores nucleares desarrollados para tres especies congenéricas y ii) 10 marcadores cloroplásticos universales diseñados para Nicotiana tabacum. Diecisiete de los 26 marcadores evaluados resultaron transferibles, de los cuales 14 fueron polimórficos siendo así útiles para futuros trabajos. Las regiones nucleares se mostraron más variables y por lo tanto más informativas que las cloroplásticas. La amplificación cruzada funcionó mejor para los marcadores nucleares específicos de Centaurea que para los cloroplásticos universales específicos de Nicotiana tabacum. A su vez, se obtuvo mejor resultado para las especies de la sección Phalolepis que para las de la sección Lepteranthus. En consecuencia, nuestros resultados apoyan la idea de que el éxito de la amplificación cruzada está estrechamente ligado a la distancia evolutiva entre especie fuente y especie objetivo.Financial support from the Spanish MICINN (Project CGL2007-60781 and CGL2010/18631) and the Generalitat de Catalunya (Ajuts a Grups de Recerca Consolidats 2009/ SGR/00439-GREB) is gratefully acknowledged.Peer reviewe

IFBiD: Inference-Free Bias Detection

Also published online by CEUR Workshop Proceedings (CEUR-WS.org, ISSN 1613-0073)This paper is the first to explore an automatic way to detect bias in deep convolutional neural networks by simply look- ing at their weights. Furthermore, it is also a step towards understanding neural networks and how they work. We show that it is indeed possible to know if a model is biased or not simply by looking at its weights, without the model infer- ence for an specific input. We analyze how bias is encoded in the weights of deep networks through a toy example using the Colored MNIST database and we also provide a realistic case study in gender detection from face images using state- of-the-art methods and experimental resources. To do so, we generated two databases with 36K and 48K biased models each. In the MNIST models we were able to detect whether they presented a strong or low bias with more than 99% ac- curacy, and we were also able to classify between four levels of bias with more than 70% accuracy. For the face models, we achieved 90% accuracy in distinguishing between models biased towards Asian, Black, or Caucasian ethnicityThis work has been supported by projects: TRESPASSETN (MSCA-ITN-2019-860813), PRIMA (MSCAITN-2019-860315), BIBECA (RTI2018-101248-B-I00 MINECO/FEDER), and BB for TAI (PID2021-127641OB-I00 MICINN/FEDER). I. Serna is supported by a FPI fellowship from UAM

Siluetas y matices : (galería filipina)

Port. a dos tintas

Exploring the Synthetic Potential of γ-Lactam Derivatives Obtained from a Multicomponent Reaction—Applications as Antiproliferative Agents

[EN] A study on the reactivity of 3-amino α,β-unsaturated γ-lactam derivatives obtained from a multicomponent reaction is presented. Key features of the substrates are the presence of an endocyclic α,β-unsaturated amide moiety and an enamine functionality. Following different synthetic protocols, the functionalization at three different positions of the lactam core is achieved. In the presence of a soft base, under thermodynamic conditions, the functionalization at C-4 takes place where the substrates behave as enamines, while the use of a strong base, under kinetic conditions, leads to the formation of C-5-functionalized γ-lactams, in the presence of ethyl glyoxalate, through a highly diastereoselective vinylogous aldol reaction. Moreover, the nucleophilic addition of organometallic species allows the functionalization at C-3, through the imine tautomer, affording γ-lactams bearing tetrasubstituted stereocenters, where the substrates act as imine electrophiles. Taking into account the advantage of the presence of a chiral stereocenter in C-5 substituted γ-lactams, further diastereoselective transformations are also explored, leading to novel bicyclic substrates holding a fused γ and δ-lactam skeleton. Remarkably, an example of a highly stereoselective formal [3+3] cycloaddition reaction of chiral γ-lactam substrates is reported for the synthesis of 1,4-dihidropyridines, where a non-covalent attractive interaction of a carbonyl group with an electron-deficient arene seems to drive the stereoselectivity of the reaction to the exclusive formation of the cis isomer. In order to unambiguously determine the substitution pattern resulting from the diverse reactions, an extensive characterization of the substrates is detailed through 2D NMR and/or X-ray experiments. Likewise, applications of the substrates as antiproliferative agents against lung and ovarian cancer cells are also described.Financial support by Ministerio de Economía, Industria y Competividad (RTI2018-101818- B-I00) and Gobierno Vasco (GV, IT 992-16) is gratefully acknowledged. X.d.C. and A.L.-F. thank the Basque Country Government for a predoctoral grant