Mostrando recursos 121 - 140 de 7.943

  1. Carolina Benanti transdisciplinary studio

    Benanti, Carolina
    Após analisar os novos comportamentos sociais, vemos que vivemos num século de grandes mudanças, onde o significado da palavra "lugar" tomou diferentes formas. Por isso, tentei realizar um estudo sobre um novo conceito, nascido neste século, baseado nesse assunto: o conceito de nuvem. A palavra "nuvem" é uma metáfora de uma visão imaginária que consiste num lugar que não possui espaço físico, mas apenas virtual. No seguimento desta análise, foi criado um serviço-produto baseado neste conceito. Está ligado à cultura Zen, um site pessoal, no qual o assinante tem a oportunidade de não só compartilhar todos os seus projetos, mas...

  2. Carolina Benanti transdisciplinary studio

    Benanti, Carolina
    Após analisar os novos comportamentos sociais, vemos que vivemos num século de grandes mudanças, onde o significado da palavra "lugar" tomou diferentes formas. Por isso, tentei realizar um estudo sobre um novo conceito, nascido neste século, baseado nesse assunto: o conceito de nuvem. A palavra "nuvem" é uma metáfora de uma visão imaginária que consiste num lugar que não possui espaço físico, mas apenas virtual. No seguimento desta análise, foi criado um serviço-produto baseado neste conceito. Está ligado à cultura Zen, um site pessoal, no qual o assinante tem a oportunidade de não só compartilhar todos os seus projetos, mas...

  3. EL ESTATUTO JURIDICO DEL CUERPO HUMANO

    Borrillo, Daniel
    Introducción La cuestión del estatuto jurídico del cuerpo humano ha hecho correr ríos de tinta. Dicho tema renvía a la vez a la naturaleza del cuerpo en el derecho, ¿se trata de una cosa o de una persona? Y a la cuestión de la propiedad del cuerpo. Quién es el titular del mismo, el individuo, el Estado, la ciencia, Dios..? En Francia, desde el principio del debate de las leyes de bioética en 1994, un cierto simplismo retórico ha opuesto dos bandos : uno inspirado de la filosofía liberal anglo-sajona que hace del cuerpo la propiedad del individuo y otro,...

  4. EL ESTATUTO JURIDICO DEL CUERPO HUMANO

    Borrillo, Daniel
    Introducción La cuestión del estatuto jurídico del cuerpo humano ha hecho correr ríos de tinta. Dicho tema renvía a la vez a la naturaleza del cuerpo en el derecho, ¿se trata de una cosa o de una persona? Y a la cuestión de la propiedad del cuerpo. Quién es el titular del mismo, el individuo, el Estado, la ciencia, Dios..? En Francia, desde el principio del debate de las leyes de bioética en 1994, un cierto simplismo retórico ha opuesto dos bandos : uno inspirado de la filosofía liberal anglo-sajona que hace del cuerpo la propiedad del individuo y otro,...

  5. High-throughput functional annotation and data

    GOTZ, STEFAN; García Gómez, Juan Miguel; Terol, Javier; Williams, Tim D.; Nagaraj, Shivashankar H.; Nueda, María José; Robles Viejo, Monserrat; Talón, Manuel; Dopazo, Joaquín; Conesa, Ana
    [EN] Functional genomics technologies have been widely adopted in the biological research of both model and non-model species. An efficient functional annotation of DNA or protein sequences is a major requirement for the successful application of these approaches as functional information on gene products is often the key to the interpretation of experimental results. Therefore, there is an increasing need for bioinformatics resources which are able to cope with large amount of sequence data, produce valuable annotation results and are easily accessible to laboratories where functional genomics projects are being undertaken. We present the Blast2GO suite as an integrated and...

  6. Model of Soft Tissue Artifact Propagation to Joint Angles in Human Movement Analysis

    Page Del Pozo, Alvaro Felipe; De Rosario Martínez, Helios; Mata Amela, Vicente; Besa Gonzálvez, Antonio José
    [EN] This work describes the kinematic laws that govern the transmission of soft tissue artifact errors to kinematic variables in the analysis of human movements. Artifacts are described as relative translations and rotations of the marker cluster over the bone, and a set of explicit expressions is defined to account for the effect of that relative motion on different representations of rotations: the rotation around the screw axis, or rotation vector, and three Euler angle sequences (XY0Z, YX0Y00, ZX0 Y00). Although the error transmission is nonlinear in all cases, the effect of artifacts is greater on Euler sequences than on...

  7. Cardiovascular fitness in youth: association with obesity and metabolic abnormalities

    Guixeres Provinciale, Jaime; REDÓN LURBE, PAU; Saiz Rodríguez, Francisco Javier; Alvarez, Julio; Torró, María Isabel; Cantero, Laura; Lurbe Ferrer, Empar
    [ES] Las terapias que se implantan actualmente para la obesidad se centran en los aspectos nutricionales y sobre la actividad física. Con el fin de hacer que la actividad física sea una terapia positiva en vez de un desencadenador de discapacidades, es relevante evaluar de forma precisa el entrenamiento cardiovascular. Objetivo: evaluar el entrenamiento cardiovascular midiendo el consumo máximo de oxígeno y evaluar su relación con los parámetros cardiometabólicos clásicos. Métodos: se aplicó el protocolo modificado de Balke a 126 individuos caucásicos (60 % de varones), con edades entre 9 y 16 años, que se sometieron a una evaluación de obesidad. El grupo de no obesos consistía de individuos sanos, de la población...

  8. Interacciones parásito-hospedador y especiación en peces cíclidos de lagunas cratéricas neotropicales

    Hofmann, Melinda Jeanet
    Desde que Darwin lo propuso por primera vez en 1859, la selección natural ha sido considerada como el principal motor de la diversificación. Sin embargo, a pesar de ello, la especiación se ha considerado como el resultado de procesos aleatorios, en los que la deriva genética juega un papel importante. Sólo en las últimas décadas se ha llegado al consenso de que hay que invertir los esfuerzos en la identificación de los mecanismos responsables de la evolución del aislamiento reproductivo, especialmente en casos donde el flujo de genes no tiene barreras físicas (i.e., la especiación simpátrica). Este cambio ha dado...

  9. Correlation between local structure and magnetic behavior in co-sputtered Tb_xFe_(73)Ga_(27-x) (7 ≤ x ≤11) thin films

    Muñoz Noval, A.; Salas Colera, E.; Bartolomé Izquierdo, Pablo; Serrano, A.; Castro, G. R.; Ranchal Sánchez, Rocío
    We report on the evolution of the microstructure of Tb-Fe-Ga films deposited by co-sputtering from Tb_(33)Fe_(67) and Fe_(72)Ga_(28) targets. The sputtering power was fixed (90 W) in the Fe_(72)Ga_(28) whereas it was increased from 50 to 90 W in the Tb_(33)Fe_(67) target resulting on Tb_xFe_(73)Ga_(27-x) layers with 7 ≤ x ≤ 11. The local structure was determined by means of x-ray absorption fine structure spectroscopy at Fe-K, Ga-K and Tb-L_(3) edges. The increase of Tb in the alloy promotes the phase segregation that produces a larger amount of the TbFe_2 structural phase. The structural results have been correlated with the...

  10. Correlation between local structure and magnetic behavior in co-sputtered Tb_xFe_(73)Ga_(27-x) (7 ≤ x ≤11) thin films

    Muñoz Noval, A.; Salas Colera, E.; Bartolomé Izquierdo, Pablo; Serrano, A.; Castro, G. R.; Ranchal Sánchez, Rocío
    We report on the evolution of the microstructure of Tb-Fe-Ga films deposited by co-sputtering from Tb_(33)Fe_(67) and Fe_(72)Ga_(28) targets. The sputtering power was fixed (90 W) in the Fe_(72)Ga_(28) whereas it was increased from 50 to 90 W in the Tb_(33)Fe_(67) target resulting on Tb_xFe_(73)Ga_(27-x) layers with 7 ≤ x ≤ 11. The local structure was determined by means of x-ray absorption fine structure spectroscopy at Fe-K, Ga-K and Tb-L_(3) edges. The increase of Tb in the alloy promotes the phase segregation that produces a larger amount of the TbFe_2 structural phase. The structural results have been correlated with the...

  11. Clustering resonance effects in the electronic energy spectrum of tridiagonal Fibonacci quasicrystals

    Maciá Barber, Enrique Alfonso
    In this work, we show that the fundamental structure of the electronic energy spectrum of binary Fibonacci quasicrystals can be decomposed in terms of two main contributions, stemming from two related characteristic symmetries. The algebraic approach, we introduce allows us for a unified and systematic description of the energy spectrum finer structure details in terms of block matrices commutators properties, within the framework of a renormalization approach based on transfer matrices. Close analytical expressions can be explicitly obtained by exploiting some algebraic properties of these blocks commutators. In particular, the overall main features of the electronic energy spectrum structure are...

  12. Spectral classification of one-dimensional binary aperiodic crystals: an algebraic approach

    Maciá Barber, Enrique Alfonso
    A spectral classification of general one-dimensional binary aperiodic crystals (BACs) based on both their diffraction patterns and energy spectrum measures is introduced along with a systematic comparison of the zeroth-order energy spectrum main features for BACs belonging to different spectral classes, including Fibonacci-class, precious means, metallic means, mixed means and period doubling based representatives. These systems are described by means of mixed-type Hamiltonians which include both diagonal and off-diagonal terms aperiodically distributed. An algebraic approach highlighting chemical correlation effects present in the underlying lattice is introduced. Close analytical expressions are obtained by exploiting some algebraic properties of suitable blocking schemes...

  13. Temperature-dependence of the hyperfine interaction in the cubic phase of BaHfO₃

    Lopez García,, A. R.; Presa Muñoz del Toro, Patricia de la; Rodiguez, A. M.
    The temperature dependence of the hyperfine interaction in the paraelectric phase of BaHfO₃ in the temperature range from liquid-nitrogen temperature to 1350 K has been studied. The experimental results show an Abragam-Pound mechanism for the attenuation of the angular correlation. In this cubic structure the attenuation would be consistent with a relaxation mechanism that involves O-ion hopping between vacant sites in the lattice. Using the point-charge model for the estimation of the electric field gradient produced by an O vacancy in the coordination sphere of the probe ion, the process is characterized by a correlation time τ_(c) = 12 ±...

  14. Radiation-damage produced in BaHfO₃ irradiated with thermal and fast-neutrons

    Lopez Garcia, A.; Presa Muñoz del Toro, Patricia de la; Rodriguez,, A. M.; Saitovitch, H.; Silva, P. R. J.
    Samples of BaHfO₃ were irradiated with fast and thermal neutrons to produce ^181Hf. Attenuations of the gamma-gamma perturbed angular correlations in ^181Ta were observed, and they may have been caused by the interaction between defects (produced during or after neutron irradiation) and oxygen vacancies. Several defect structures were detected. For one of the structures, an excitation energy of 12 meV was measured, which was attributed to an electron state below the conduction band. The values of the dielectric constant and of the effective electron mass were also deduced.

  15. Electronic structure of cubic SrHfO₃: Ferroelectric stability and detailed comparison with SrTiO₃

    Fabricius, G.; Peltzer, E. L.; Rodriguez, Blanca; Rodriguez, C. R.; Ayala, A. P.; Presa Muñoz del Toro, Patricia de la; Lopez García, A.
    Electronic structure calculations of cubic SrTiO₃ and SrHfO₃ are presented. The full-potential linear augmented-plane-wave method is used and exchange-correlation effects are treated by the local-density approximation. The tendency to ferroelectricity of both compounds is explored and compared by displacing the transition metal atom (Ti or Hf) towards one of the oxygens (001 direction). The calculations show that ferroelectricity is favored in SrTiO₃ with respect to SrHfO₃ and that this fact may be correlated with the degree of hybridization between transition metal d-O p bands as has been found for other related systems. Also a detailed discussion of the calculated electric...

  16. Structural phase transitions in BaTi0₃ studied via perturbed angular correlations

    Roth,, J.; Uhrmacher,, M.; Presa Muñoz del Toro, Patricia de la; Ziegeler, L.; Lieb, K. P.
    Phase transitions in the ferroelectric perovskite BaTiO₃ were studied for ^111In-implanted polycrystalline samples by measuring the electric field gradients by means of Perturbed Angular Correlation spectroscopy. The phase transitions between the orthorhombic double left right arrow rhombohedral double left right arrow tetragonal double left right arrow cubic lattices were investigated in 2 - 10 K steps, for increasing and decreasing temperatures, in order to determine their hysteresis. The transition parameters are compared with results from measurements of the spontaneous polarization, electric susceptibility and neutron scattering.

  17. Perturbed Angular Correlation Studies in SrTi0₃ Single Crystals

    Presa Muñoz del Toro, Patricia de la; Lieb, K. P.; Uhrmacher, M.; Ziegeler, L.
    The quadrupole hyperfine interactions of ^111Cd/^111 probe nuclei in single-crystalline SrTiO₃ perovskite samples were investigated using Perturbed Angular Correlation spectroscopy. Three electric field gradients were detected and their fractions and hyperfine parameters were measured in the temperature range from 26 to 700 K. The fraction f₀ having a vanishing quadrupole frequency, as expected for ^111Cd on substitutional sites in a cubic lattice, starts to develop around 300 K and reaches 100% at 700 K. Two well-defined EFG's having closely lying quadrupole frequencies and asymmetry parameters of ω_(Q1) = 49.1(3) Mrad/s, η_(1) = 0.10(2) and ω_(Q2) = 51 8(3) Mrad/s, η_(2)=...

  18. Anisotropic relaxations introduced by Cd impurities in rutile TiO₂: First-principles calculations and experimental support

    Errico, L. A.; Fabricius, G.; Rentería, M; Presa Muñoz del Toro, Patricia de la; Forker, M.
    We present an ab initio study of the relaxations introduced in TiO₂ when a Cd impurity substitutes a Ti atom and an experimental test of this calculation by a perturbed-angular-correlation (PAC) measurement of the orientation of the electric-field gradient (EFG) tensor at the Cd site. The ab initio calculation predicts strong anisotropic relaxations of the nearest oxygen neighbors of the impurity and a change of the orientation of the largest EFG tensor component, V_(33) , from the [001] to the [110] direction upon substitution of a Ti atom by a Cd impurity. The last prediction is confirmed by the PAC...

  19. Perturbed angular correlation study of the magnetic phase transitions in the rare-earth cobalt Laves phases RCo₂

    Forker, M.; Müller, S.; Presa Muñoz del Toro, Patricia de la
    The order and other properties of the magnetic phase transitions in the rare-earth (R)-cobalt Laves phases RCo2 have been studied for R=Gd, Tb, Dy, Ho, Er, Sm, Nd, and Pr by measuring the temperature dependence of the magnetic hyperfine interaction of the nuclear probe ^111Cdon the cubic R sites using the perturbed angular correlation technique. Both for heavy and light R constituents the transitions change from second order (Gd, Tb, Sm) to first order (Dy, Ho, Er, Nd, Pr) at order temperatures of 150-200 K. For heavy R constituents, the order deduced from the hyperfine interaction is in agreement with...

  20. Vacancy motion in rare-earth-deficient R_(1-x)Ni_2 Laves phases observed by perturbed angular correlation spectroscopy

    Forker, M.; Presa Muñoz del Toro, Patricia de la; Müller, S:; Lindbaum, A.; Gratz, E.
    Rare-earth-deficient R_(1-x)Ni_2 Laves phases, which reportedly crystallize in a C15 superstructure with ordered R vacancies, have been investigated by perturbed angular correlation (PAC) measurements of electric quadrupole interactions at the site of the probe nucleus ^111Cd. Although ^111Cd resides on the cubic R site, a strong axially symmetric quadrupole interaction (QI) with frequencies ν(q)approximate to265-275 MHz has been found in the paramagnetic phases of R_(1-x)Ni_2 with R=Pr,Nd,Sm,Gd. This interaction is not observed for the heavy R constituents R=Tb,Dy,Ho,Er. The fraction of probe nuclei subject to the QI in R_(1-x)Ni_2, R=Pr,Nd,Sm,Gd, decreases from 100% at low temperatures to zero at T>300...

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