Scattering at the Anderson transition: Power--law banded random matrix model

We analyze the scattering properties of a periodic one-dimensional system at criticality represented by the so-called power-law banded random matrix model at the metal insulator transition. We focus on the scaling of Wigner delay times $\tau$ and resonance widths $\Gamma$. We found that the typical values of $\tau$ and $\Gamma$ (calculated as the geometric mean) scale with the system size $L$ as $\tau^{\tiny typ}\propto L^{D_1}$ and $\Gamma^{\tiny typ} \propto L^{-(2-D_2)}$, where $D_1$ is the information dimension and $D_2$ is the correlation dimension of eigenfunctions of the corresponding closed system.Comment: 6 pages, 8 figure

Parametric invariant Random Matrix Model and the emergence of multifractality

We propose a random matrix modeling for the parametric evolution of eigenstates. The model is inspired by a large class of quantized chaotic systems. Its unique feature is having parametric invariance while still possessing the non-perturbative crossover that has been discussed by Wigner 50 years ago. Of particular interest is the emergence of an additional crossover to multifractality.Comment: 7 pages, 6 figures, expanded versio

Scaling properties of delay times in one-dimensional random media

The scaling properties of the inverse moments of Wigner delay times are investigated in finite one-dimensional (1D) random media with one channel attached to the boundary of the sample. We find that they follow a simple scaling law which is independent of the microscopic details of the random potential. Our theoretical considerations are confirmed numerically for systems as diverse as 1D disordered wires and optical lattices to microwave waveguides with correlated scatterers.Comment: 5 pages, 4 figures Submitted to Physical Review B Revision 2: 1) Theoretical curve fits added to Figures 1-4. 2) Scaling parameter added to inset of Figure 2. 3) Minor text changes to reflect referee comments. 4) Some extra refereces were adde

SJM: Un simulador de jerarquías de memoria orientado a la docencia de arquitectura de computadores

El concepto de jerarquía de memoria de un computador es uno de los más importantes en el ámbito de la docencia en arquitectura de computadores. Habitualmente, los distintos aspectos de la estructura y el funcionamiento de la jerarquía de memoria (memoria cache, memoria virtual, algoritmos de reemplazo, tasas de fallos, etc.) se explican primero a los alumnos de manera teórica, y posteriormente se realizan prácticas basadas en programas que simulan dicha jerarquía. En este trabajo se presenta un nuevo simulador pedagógico, SJM, que permite modelar de forma amigable distintas jerarquías de memoria, modificar fácilmente sus características y obtener medidas de sus prestaciones, de cara a que los alumnos, mediante la evaluación de distintas configuraciones de la jerarquía de memoria, afiancen su comprensión de los distintos aspectos de ésta.Peer Reviewe

Two-dimensional proteome reference map of Vibrio tapetis, the aetiological agent of brown ring disease in clams

Aims: Vibrio tapetis is the etiological agent of brown ring disease (BRD) in clams, one of the most threatening diseases affecting this commercially important bivalve. In this study we have constructed a proteome reference map of the V. tapetis type strain CECT 4600T. Methods and Results: Eighty-two proteins, consistently present in all 2D-gels, were identified by mass spectrometry or by de novo sequencing. The majority of the proteins identified (66%) belonged to four COG categories: 'Carbohydrate transport and metabolism', 'Post-translational modification, protein turnover and chaperones', 'Energy production', and 'Amino acid transport and metabolism'. Glyceraldehyde-3-phosphate dehydrogenase, enolase, fructose-bisphosphate aldolase, phosphoglycerate kinase. molecular chaperones Dnak and GroEL, alkyl hydroperoxide reductase, peptidyl-prolyl cis-trans isomerase B and factor Tu, were identified among the 20 most abundant proteins. A comparison of this reference map with that obtained for the V. tapetis strain GR0202RD, with different origin and pathophysiological characteristics, was performed. Conclusions: Under the culture conditions employed in this study, glucose degradation is one of the major pathways for energy production in Vibrio tapetis. In addition, the two strains studied, although with remarkable differences at genetic and pathophysiological levels, showed a high similarity under laboratory conditions. Significance and Impact of the Study: The results obtained here can be considered as a first step to gather valuable information on protein expression, related not only to diverse cellular functions and regulation but also to pathogenesis and bacterium-host interactions in the disease process

Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Vinyl Cyanide in Orion-KL

New laboratory data of CH$_2$CHCN (vinyl cyanide) in its ground and vibrationally excited states at the microwave to THz domain allow searching for these excited state transitions in the Orion-KL line survey. Frequency-modulated spectrometers combined into a single broadband 50-1900 GHz spectrum provided measurements of CH$_2$CHCN covering a spectral range of 18-1893 GHz, whose assignments was confirmed by Stark modulation spectra in the 18-40 GHz region and by ab-initio anharmonic force field calculations. For analyzing the emission lines of CH$_2$CHCN species detected in Orion-KL we used the excitation and radiative transfer code (MADEX) at LTE conditions. The rotational transitions of the ground state of this molecule emerge from four cloud components of hot core nature which trace the physical and chemical conditions of high mass star forming regions in the Orion-KL Nebula. The total column density of CH$_2$CHCN in the ground state is (3.0$\pm$0.9)x10$^{15}$ cm$^{-2}$. We report on the first interstellar detection of transitions in the v10=1/(v11=1,v15=1) dyad in space, and in the v11=2 and v11=3 states in Orion-KL. The lowest energy vibrationally excited states of vinyl cyanide such as v11=1 (at 328.5 K), v15=1 (at 478.6 K), v11=2 (at 657.8 K), the v10=1/(v11=1,v15=1) dyad (at 806.4/809.9 K), and v11=3 (at 987.9 K) are populated under warm and dense conditions, so they probe the hottest parts of the Orion-KL source. Column density and rotational and vibrational temperatures for CH$_2$CHCN in their ground and excited states, as well as for the isotopologues, have been constrained by means of a sample of more than 1000 lines in this survey. Moreover, we present the detection of methyl isocyanide (CH$_3$NC) for the first time in Orion-KL and a tentative detection of vinyl isocyanide (CH$_2$CHNC) and give column density ratios between the cyanide and isocyanide isomers.Comment: 46 pages, 22 figures, 14 tables, 9 online table

PROBABILISTIC ASSESSMENT OF THE SEISMIC PERFORMANCE OF STEEL BUILDINGS DESIGNED ACCORDING TO THE LRFD SPECIFICATION

Seismic regulations and building codes experienced major advances in the last decades. Nevertheless, current trends in earthquake engineering are the assessment of the computational procedures provided by such design rules, by using probabilistic techniques, in order to test the anticipated levels of reliability and performance of the structures. While some consideration is given in codes to the uncertainties associated to the seismic action, no probabilistic requirements are posed on the responses, which determine the final design. Consequently, the risk associated to the design formulas remains unknown. The objective of this chapter is to study whether steel buildings designed and constructed according to the Load and Resistance Factor Design (LRFD) specification for Structural Steel Buildings, reasonably meet the probabilistic requirements on structural member safety applying non-linear dynamic analyses and Monte-Carlo techniques. Starting from a specific low-rise braced frame steel building existing in Manizales, Colombia, we also analyze mid-rise and high-rise braced frame buildings. Similar low- mid- and high-rise Moment-resisting frame buildings are also studied. For each building we performed more than ten thousand dynamic simulations, covering a wide range of combinations of demand and strength. In this way, we determine the exceedance probability of the construction capacity and we verify the safety and reliability of the structural members of the buildings. In the analysis of demand, we consider the probabilistic variation of the vertical gravity loads as well as of the seismic horizontal ones. The analyses of the strength of the studied buildings take into account the uncertainties and probability distributions of several parameters as: the yielding strain, the elasticity modulus, the cross-sectional area and their inertia moments. The analysis shows that in the cases here analyzed, but especially in moment-resisting frame buildings, the uncertainties in the input parameters may lead to significant failure probabilities. We conclude that braced frame steel buildings fulfil the seismic safety requirements while moment-resisting frame buildings would require a safety factor of about 2.7 for the column anchorages to the foundations

Physiologically attentive user interface for robot teleoperation: real time emotional state estimation and interface modification using physiology, facial expressions and eye movements

We developed a framework for Physiologically Attentive User Interfaces, to reduce the interaction gap between humans and machines in life critical robot teleoperations. Our system utilizes emotional state awareness capabilities of psychophysiology and classifies three emotional states (Resting, Stress, and Workload) by analysing physiological data along with facial expression and eye movement analysis. This emotional state estimation is then used to create a dynamic interface that updates in real time with respect to user’s emotional state. The results of a preliminary evaluation of the developed emotional state classifier for robot teleoperation are presented, along with its future possibilities are discussed.info:eu-repo/semantics/acceptedVersio