Task adaption by biologically inspired stochastic comodulation

Brain representations must strike a balance between generalizability and adaptability. Neural codes capture general statistical regularities in the world, while dynamically adjusting to reflect current goals. One aspect of this adaptation is stochastically co-modulating neurons' gains based on their task relevance. These fluctuations then propagate downstream to guide decision-making. Here, we test the computational viability of such a scheme in the context of multi-task learning. We show that fine-tuning convolutional networks by stochastic gain modulation improves on deterministic gain modulation, achieving state-of-the-art results on the CelebA dataset. To better understand the mechanisms supporting this improvement, we explore how fine-tuning performance is affected by architecture using Cifar-100. Overall, our results suggest that stochastic comodulation can enhance learning efficiency and performance in multi-task learning, without additional learnable parameters. This offers a promising new direction for developing more flexible and robust intelligent systems

Multidimensional subwavelength position sensing using a semiconductor laser with optical feedback

We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength λ≈1550nm, we achieve an average nanoscale resolution of approximately 9.8 nm (∼λ∕160).Peer ReviewedPostprint (published version

Una Alternativa Para La Realización De Laboratorios Docentes En Ingeniería

This work describes the accomplishment of a practical laboratory of support to a theoretical course in which the student must accomplish most of the work, included the assembly of the elements he will work with. In this way, stimulating the student to be more ingenious, smarter, more creative, difficult aspects to be achieved in conventional laboratory practices. The preliminary evaluation of this experience is shown in this article

Synthesis and Characterization of High Temperature Properties of YBa2Cu3O6+δ Superconductor as Potential Cathode for Intermediate Temperature Solid Oxide Fuel Cells

YBa2Cu3O6+δ (YBC) oxygen deficient perovskite was synthesized by an auto-combustion method and was studied as potential cathode for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). Synchrotron X-ray thermodiffraction in air shows a phase transition from orthorhombic Pmmm to tetragonal P4/mmm space groups at ~ 425 °C. The chemical compatibility with Ce0.9Gd0.1O1.95 (GDC) electrolyte was investigated in air where certain reactivity wasobserved above 800 °C. However, the main phase is Ba(Ce1-xYx)O3, a good ionic conductor. The catalytic performance in air was obtained by electrochemical impedance spectroscopy (EIS) measurements on YBC/GDC/YBC symmetrical cells. The area specific resistance (ASR) values change from 13.66 to 0.14 Ω cm2 between 500 and 800 °C, with activation energy (Ea) of 0.41 eV. The results suggest potential applications of YBC as IT-SOFC cathode.Fil: Grassi, Joaquín. Universidad de la República. Facultad de Química; UruguayFil: Macías, Mario A.. Universidad de los Andes; ColombiaFil: Basbus, Juan Felipe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Castiglioni, Jorge. Universidad de la República. Facultad de Química; UruguayFil: Gauthier, Gilles H.. Universidad Industrial Santander; ColombiaFil: Serquis, Adriana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Suescun, Leopoldo. Universidad de la República. Facultad de Química; Urugua

Multinuclear solid-state NMR investigation of Hexaniobate and Hexatantalate compounds

This work determines the potential of solid-state NMR techniques to probe proton, alkali, and niobium environments in Lindqvist salts. Na7HNb6O19·15H2O (1), K8Nb6O19·16H2O (2), and Na8Ta6O19·24.5H2O (3) have been studied by solid-state static and magic angle spinning (MAS) NMR at high and ultrahigh magnetic field (16.4 and 19.9 T). 1H MAS NMR was found to be a convenient and straightforward tool to discriminate between protonated and nonprotonated clusters AxH8–xM6O19·nH2O (A = alkali ion; M = Nb, Ta). 93Nb MAS NMR studies at different fields and MAS rotation frequencies have been performed on 1. For the first time, the contributions of NbO5Oμ2H sites were clearly distinguished from those assigned to NbO6 sites in the hexaniobate cluster. The strong broadening of the resonances obtained under MAS was interpreted by combining chemical shift anisotropy (CSA) with quadrupolar effects and by using extensive fitting of the line shapes. In order to obtain the highest accuracy for all NMR parameters (CSA and quadrupolar), 93Nb WURST QCPMG spectra in the static mode were recorded at 16.4 T for sample 1. The 93Nb NMR spectra were interpreted in connection with the XRD data available in the literature (i.e., fractional occupancies of the NbO5Oμ2H sites). 1D 23Na MAS and 2D 23Na 3QMAS NMR studies of 1 revealed several distinct sodium sites. The multiplicity of the sites was again compared to structural details previously obtained by single-crystal X-ray diffraction (XRD) studies. The 23Na MAS NMR study of 3 confirmed the presence of a much larger distribution of sodium sites in accordance with the 10 sodium sites predicted by XRD. Finally, the effect of Nb/Ta substitutions in 1 was also probed by multinuclear MAS NMR (1H, 23Na, and 93Nb)

Control Systems Engineering made Easy: Motivating Students through Experimentation on UAVs

International audienceThis paper focuses on a new elective course on modeling and control of multi-agent systems, with experimentation on Unmanned Aerial Vehicles (UAVs). The module is taught for students with basic knowledge in Automatic Control and Optimization and it intends to increase their interest in applying advanced control techniques on UAVs in an enjoyable framework favorable to develop creativity, practical and team working skills, together with a solid and persistent theoretical background

El Uso De La Logica Difusa Para La Potabilizacion Del Agua

El proceso central en una planta de potablización de agua es el de coagulación el cual se maneja frecuentemente en forma manual. Este trabajo presenta una alternativa de control automático de estos procesos, la cual usa la teoría de conjuntos difusos. Se aplicó a la planta Wiesner de Bogotá que suministra cerca del 70% del agua de la ciudad, con muy buenos resultados con respecto a la turbiedad del agua filtrada que se entrega a la red de distribución. Se hizo uso de un equipo denominado SCD (sreaming current detector) el cual permite obtener una medida del estado de carga de las partículas en suspensión y de esa manera calcular la dosis del coagulante que se debe aplicar

Agitation in cognitive disorders: International Psychogeriatric Association provisional consensus clinical and research definition

Background: Agitation is common across neuropsychiatric disorders and contributes to disability, institutionalization, and diminished quality of life for patients and their caregivers. There is no consensus definition of agitation and no widespread agreement on what elements should be included in the syndrome. The International Psychogeriatric Association formed an Agitation Definition Work Group (ADWG) to develop a provisional consensus definition of agitation in patients with cognitive disorders that can be applied in epidemiologic, non-interventional clinical, pharmacologic, non-pharmacologic interventional, and neurobiological studies. A consensus definition will facilitate communication and cross-study comparison and may have regulatory applications in drug development programs. Methods: The ADWG developed a transparent process using a combination of electronic, face-to-face, and survey-based strategies to develop a consensus based on agreement of a majority of participants. Nine-hundred twenty-eight respondents participated in the different phases of the process. Results: Agitation was defined broadly as: (1) occurring in patients with a cognitive impairment or dementia syndrome; (2) exhibiting behavior consistent with emotional distress; (3) manifesting excessive motor activity, verbal aggression, or physical aggression; and (4) evidencing behaviors that cause excess disability and are not solely attributable to another disorder (psychiatric, medical, or substance-related). A majority of the respondents rated all surveyed elements of the definition as strongly agree or somewhat agree (68-88 across elements). A majority of the respondents agreed that the definition is appropriate for clinical and research applications. Conclusions: A provisional consensus definition of agitation has been developed. This definition can be used to advance interventional and non-interventional research of agitation in patients with cognitive impairment. Copyright © International Psychogeriatric Association 2014