Colecciones de Investigación y Producción Científica - Ikerketa eta ekoizpen zientifikoko Bildumak

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Open Access
±0.25 V Class-AB CMOS capacitance multiplier and precision rectifiers
(IEEE, 2019) Pourashraf, Shirin; Ramírez-Angulo, Jaime; Hinojo Montero, José María; González Carvajal, Ramón; López Martín, Antonio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Reduction of minimum supply requirements is a crucial aspect to decrease the power consumption in VLSI systems. A high performance capacitance multiplier able to operate with supplies as low as ±0.25 V is presented. It is based on adaptively biased class-AB current mirrors which provide high current efficiency. Measurement results of a factor 11 capacitance multiplier fabricated in 180 nm CMOS technology verify theoretical claims. Moreover, low-voltage precision rectifiers based on the same class-AB current mirrors are designed and fabricated in the same CMOS process. They generate output currents over 100 times larger than the quiescent current. Both proposed circuits have 300 nW static power dissipation when operating with ±0.25 V supplies.
Open Access
±0.3v bulk-driven fully differential buffer with high figures of merit
(MDPI, 2022) Gangineni, Manaswini; Ramírez-Angulo, Jaime; Vázquez-Leal, Héctor; Huerta-Chua, Jesús; López Martín, Antonio; González Carvajal, Ramón; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
A high performance bulk-driven rail-to-rail fully differential buffer operating from ±0.3V supplies in 180 nm CMOS technology is reported. It has a differential–difference input stage and common mode feedback circuits implemented with no-tail, high CMRR bulk-driven pseudo-differential cells. It operates in subthreshold, has infinite input impedance, low output impedance (1.4 kΩ), 86.77 dB DC open-loop gain, 172.91 kHz bandwidth and 0.684 µWstatic power dissipation with a 50-pF load capacitance. The buffer has power efficient class AB operation, a small signal figure of merit FOMss = 12.69 MHzpFµW-1, a large signal figure of merit FOMls = 34.89 (V/µs) pFµW-1, CMRR = 102 dB, PSRR+ = 109 dB, PSRR- = 100 dB, 1.1 µV/√Hz input noise spectral density, 0.3 mVrms input noise and 3.5 mV input DC offset voltage.
Open Access
0.6-V 1.65-uW second-order Gm-C bandpass filter for multi-frequency bioimpedance analysis based on a bootstrapped bulk-driven voltage buffer
(MDPI, 2022) Carrillo, Juan M.; Cruz Blas, Carlos Aristóteles de la; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A bootstrapping technique used to increase the intrinsic voltage gain of a bulk-driven MOS transistor is described in this paper. The proposed circuit incorporates a capacitor and a cutoff transistor to be connected to the gate terminal of a bulk-driven MOS device, thus achieving a quasi- floating-gate structure. As a result, the contribution of the gate transconductance is cancelled out and the voltage gain of the device is correspondingly increased. The technique allows for implementing a voltage follower with a voltage gain much closer to unity as compared to the conventional bulk-driven case. This voltage buffer, along with a pseudo-resistor, is used to design a linearized transconduc- tor. The proposed transconductance cell includes an economic continuous tuning mechanism that permits programming the effective transconductance in a range sufficiently wide to counteract the typical variations that process parameters suffer during fabrication. The transconductor has been used to implement a second-order Gm-C bandpass filter with a relatively high selectivity factor, suited for multi-frequency bioimpedance analysis in a very low-voltage environment. All the circuits have been designed in 180 nm CMOS technology to operate with a 0.6-V single-supply voltage. Simulated results show that the proposed technique allows for increasing the linearity and reduc- ing the input-referred noise of the bootstrapped bulk-driven MOS transistor, which results in an improvement of the overall performance of the transconductor. The center frequency of the bandpass filter designed can be programmed in the frequency range from 6.5 kHz to 37.5 kHz with a power consumption ranging between 1.34 μW and 2.19 μW. The circuit presents an in-band integrated noise of 190.5 μVrms and is able to process signals of 110 mVpp with a THD below −40 dB, thus leading to a dynamic range of 47.4 dB
Open Access
0.6-V CMOS bulk-driven instrumentation amplifier for IoMT bioimpedance analysis
(Wiley, 2024) Carrillo, Juan M.; Ocampo-Hidalgo, Juan J.; Corbacho, Israel; Cruz Blas, Carlos Aristóteles de la; Domínguez, Miguel Á.; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
An instrumentation amplifier (IA), aimed at wideband bioimpedance analysisin the low-voltage low-power scenario of internet of medical things (IoMT), ispresented. The operation principle is based on the indirect current feedbacktechnique, where an input and a feedback transconductor determine thevoltage gain of the preamplifier. The required transconductors consist of twobulk-driven flipped-voltage-follower cells and an active pseudo-resistor, thusleading to a linear and compact implementation. The circuit has been designedand fabricated in 180 nm CMOS technology to operate with a 0.6-V supply.Experimental results obtained from measurements on eight samples of thesilicon prototype show that when the IA is programmed to have a nominalvoltage gain of 11 V/V, the bandwidth is 316.2 kHz, the CMRR exceeds63 dB, and the maximum output voltage that can be processed with a THDbelow –40 dB is 555 mVpp.
Open Access
1-V 15-μW 130-nm CMOS super class AB OTA
(IEEE, 2020) López Martín, Antonio; Algueta-Miguel, Jose M.; Garde Luque, María Pilar; Carvajal, Ramón G.; Ramírez-Angulo, Jaime; Institute of Smart Cities - ISC
A super class AB recycling folded cascode amplifier in 130 nm CMOS is presented. It combines for the first time adaptive biasing of the differential input pair, nonlinear current mirrors with current starving and dynamic biasing of the cascode transistors in the output branch. Measurements using a ±0.5V supply show slew rate and gain bandwidth product improvement factors of 26 and 112 versus the conventional topology for the same bias currents, yielding the highest combined FoM to date.
Open Access
A 1.2-V current-mode RMS-to-DC converter based on a novel two-quadrant electronically simulated MOS translinear loop
(IEEE, 2020) Martincorena Arraiza, Maite; Cruz Blas, Carlos Aristóteles de la; Algueta-Miguel, Jose M.; López Martín, Antonio; Institute of Smart Cities - ISC
A novel current-mode CMOS RMS-to-DC converter using translinear techniques is introduced. It is based on a squarer/divider cell that is implemented using an electronically simulated loop with a novel biasing scheme that allows its operation in two quadrants. The cell is designed using a differential input current and a small signal first order filter to implement the voltage averaging, leading to a compact solution that can be used with low voltage supplies. The converter has been fabricated in a standard 130-nm CMOS process, and measurement results are provided to demonstrate the feasibility of the system.
Open Access
100 años de Leonard Bernstein, 60 años de los Conciertos para Jóvenes
(IFIDMA, 2018) Sáenz Abárzuza, Igor; Ciencias Humanas y de la Educación; Giza eta Hezkuntza Zientziak
18 de enero del año 1958. Obertura de Guillaume Tell, compás 226, Allegro Vivace. Al acabar la pieza, el director y presentador del concierto, Leonard Bernstein[1], dirigido al joven auditorio, preguntaba: “Bien. ¿De qué creéis que trata esta música? ¿me lo podéis decir?”. Las niñas y niños, sin conocer los códigos de silencio tradicionales de los auditorios, se ponen a contestar al maestro, a lo que él dice: “Sabía que me ibais a decir eso”. Con esa música y una enorme capacidad comunicativa empezaba el primer Concierto Para Jóvenes dirigido por Bernstein y televisado por la CBS, poco después de que tomara las riendas de la New York Pilharmonic. Este primer programa llevaba por título “¿What does Music mean?”[2], y es todavía a día de hoy una lección magistral tanto para aficionados a la música de todas las edades como para músicos profesionales. Si bien la orquesta ya contaba previamente con un programa de conciertos dirigido a estudiantes, Bernstein transformó el modelo para siempre.
Open Access
101 Dothideomycetes genomes: a test case for predicting lifestyles and emergence of pathogens
(Westerdijk Fungal Biodiversity Institute, 2020) Haridas, Sajeet; Castanera Andrés, Raúl; Culley, D. E.; Daum, C.; Ramírez Nasto, Lucía; Alfaro Sánchez, Manuel; Institute for Multidisciplinary Research in Applied Biology - IMAB
Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species.
Open Access
119Sn Mössbauer spectroscopy for assessing the local stress and defect state towards the tuning of Ni-Mn-Sn alloys
(AIP Publishing, 2017) Unzueta, Iraultza; López García, Javier; Sánchez-Alarcos Gómez, Vicente; Recarte Callado, Vicente; Pérez de Landazábal Berganzo, José Ignacio; Fisika; Institute for Advanced Materials and Mathematics - INAMAT2; Física
The influence of defects and local stresses on the magnetic properties and martensitic transformation in Ni50Mn35Sn15 is studied at macroscopic and atomic scale levels. We show that both the structural and magnetic properties of the alloy are very sensitive to slight microstructural distortions. Even though no atomic disorder is induced by milling, the antiphase boundaries linked to dislocations promote the antiferromagnetic coupling of Mn, resulting in a significant decrease in the saturation magnetization. On the other hand, the temperature range of the transformation is considerably affected by the mechanically induced local stresses, which in turn does not affect the equilibrium temperature between the austenitic and martensitic phases. Finally, we demonstrate that the recovery of the martensitic transformation is directly related to the intensity of the non-magnetic component revealed by 119Sn Mössbauer spectroscopy. This result opens the possibility of quantifying the whole contribution of defects and the local stresses on the martensitic transformation in Ni-Mn-Sn alloys.
Open Access
15-item version of the Boston naming test: normative data for the Latin American spanish-speaking adult population.
(American Psychological Association, 2023) Del Cacho Tena, Ana María; Merced, Kritzia; Perrin, Paul B.; Arango Lasprilla, Juan Carlos; Olabarrieta Landa, Laiene; Rivera, Diego; Ciencias de la Salud; Osasun Zientziak
Objective: Naming is commonly impaired in people with neurodegenerative diseases and brain injury, and as a result, its accurate assessment is essential. The aim of this study was to provide normative data for the 15-item Spanish version of the Boston Naming Test (BNT) for an adult population from eight Latin American countries/regions. Method: The total sample consisted of 2,828 participants from Argentina, Chile, Cuba, El Salvador, Mexico, Honduras, Paraguay, and Puerto Rico. Multiple regressions were used to generate normative data following a four-step process. Results: Regression models showed a linear effect of age on the 15-item BNT total score for Argentina, Chile, Mexico, and Puerto Rico. In contrast, Paraguay showed a quadratic age effect. Almost all countries showed a positive linear effect of education, except Cuba which had a quadratic effect. Sex was a significant predictor in Argentina, Chile, Cuba, and Mexico, where in women scored lower than men. Conclusions: This study generates normative data for the 15-item Spanish version of the BNT and offers a free open-source calculator that will assist in the efficacious use of this neuropsychological test in clinical practice and research.
Open Access
150 años de historia de la ética del Trabajo Social en España: periodización de sus valores éticos
(Universidad Complutense de Madrid, 2017) Idareta Goldaracena, Francisco; Úriz Pemán, María Jesús; Viscarret Garro, Juan Jesús; Trabajo Social; Gizarte Lana
Desde que iniciase su andadura como profesión en España, ha quedado constancia del compromiso ético de las y los profesionales del Trabajo Social en las respuestas que han venido ofreciendo en cada época a los conflictos y dilemas éticos que se originaban en el ejercicio profesional. Ante la ausencia de estudios de similares características a nivel nacional, el objetivo del presente artículo consiste en explicar nuestra propuesta de periodización de la evolución del compromiso ético de las y los profesionales del Trabajo Social en España a partir del estudio de los valores éticos que han sido destacados por las y los mismos desde 1861 hasta la actualidad. Para ello, explicaremos los diferentes períodos en los que hemos estructurado la evolución de la Ética del Trabajo Social en España, identificando algunos elementos del estoicismo.
Open Access
20-Year trajectories of six psychopathological dimensions in patients with first-episode psychosis: could they be predicted?
(Elsevier, 2024) Cuesta, Manuel J.; Gil Berrozpe, Gustavo José; Sánchez Torres, Ana María; Moreno-Izco, Lucía; García de Jalón, Elena; Peralta Martín, Víctor; SEGPEPs Group; Ciencias de la Salud; Osasun Zientziak
Patients with first-episode psychoses (FEP) exhibit heterogeneity in clinical manifestations and outcomes. This study investigated the long-term trajectories of six key psychopathological dimensions (reality-distortion, negative, disorganization, catatonia, mania and depression) in patients diagnosed with FEP. A total of 243 patients were followed up for 20 years and the trajectories of the dimensions were analysed using growth mixture modelling. These dimensions showed varied course patterns, ranging from two to five trajectories. Additionally, the study examined the predictive value of different factors in differentiating between the long-term trajectories. The exposome risk score showed that familial load, distal and intermediate risk factors, acute psychosocial stressors and acute onset were significant predictors for differentiating between long-term psychopathological trajectories. In contrast, polygenic risk score, duration of untreated psychosis and duration of untreated illness demonstrated little or no predictive value. The findings highlight the importance of conducting a multidimensional assessment not only at FEP but also during follow-up to customize the effectiveness of interventions. Furthermore, the results emphasize the relevance of assessing premorbid predictors from the onset of illness. This may enable the identification of FEP patients at high-risk of poor long-term outcomes who would benefit from targeted prevention programs on specific psychopathological dimensions.
Open Access
200 years diversifying the energy mix? Diversification paths of the energy baskets of European early comers vs. latecomers
(Universidad Autónoma de Madrid, 2017) Rubio Varas, María del Mar; Muñoz Delgado, Beatriz; Economía; Ekonomia
The changes in the composition of the energy basket in the long run lead to energy transitions. Primary energy substitution models allow addressing these phenomena. However, the diversification paths of the energy mix of different countries in a long term compared perspective have not been studied yet. This paper proposes an indicator, based on the Herfindahl‐Hirschman Index, the Energy Mix Concentration Index (EMCI), to quantify the degree of diversification of the primary energy basket of eight European countries over the last two centuries. The results reveal that early comers, which are large energy consumers, required a huge concentration of their energy basket in the 19th century; however, the observed countries had converged to similar levels of diversification of their energy mixes from the second half of the 20th century, and more crucially after the oil crises. For some countries, today’s degree of diversification is the largest in their energy histories, but it is not the case for all of them. Our results suggest that small energy consuming countries would be able to achieve higher diversification, and therefore to do a faster transition to a low carbón economy, than large energy consumers.
Open Access
2020: el informe de la minoría y la curación de la música
(Associació Webdemusica.org, 2020) Sáenz Abárzuza, Igor; Ciencias Humanas y de la Educación; Giza eta Hezkuntza Zientziak
Reflexiones sobre el uso de la música en la publicidad y el mercado musical.
Open Access
2021 y la (L)libertad: una playlist de versiones y per-versiones de Blackbird
(Associació Webdemusica.org, 2021) Sáenz Abárzuza, Igor; Ciencias Humanas y de la Educación; Giza eta Hezkuntza Zientziak
Sobre las versiones que se han hecho de la canción Blackbird, escrita por Paul McCartney para The Beatles.
Open Access
2023, Casals y el azar
(Associació Webdemusica.org, 2023) Sáenz Abárzuza, Igor; Ciencias Humanas y de la Educación; Giza eta Hezkuntza Zientziak
Artículo escrito con motivo del cincuenta aniversario de la muerte de Pau Casals.
Open Access
25 years of continuous sewage sludge application vs. mineral fertilizers on a calcareous soil affected pH but not soil carbonates
(Frontiers Media, 2022) De Soto García, Isabel Sonsoles; Zamanian, Kazem; Urmeneta Martín-Calero, Henar; Enrique Martín, Alberto; Virto Quecedo, Íñigo; Zientziak; Estatistika, Informatika eta Matematika; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ciencias; Estadística, Informática y Matemáticas; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Inorganic and organic fertilizers have been widely used to maintain crop yields. However, several studies have demonstrated that the dissolution of carbonates in agricultural soils by the acidification induced by N-fertilizers can result in their total or partial loss in the tilled layer of some agricultural soils. The effect of inorganic and organic fertilization on carbonates in calcareous semiarid Mediterranean soils has been less studied and is still unclear. Based on a 25-year field experiment, we investigated the effects of different fertilization strategies on the soil pH, inorganic C content, and in the proportion of pedogenic carbonates in the topsoil (0-30 cm) of a carbonate-rich soil in Navarre (N Spain). Five treatments were compared: no amendments as a control (SC), mineral fertilization (MF), and the application of sewage sludge at different doses (80 Mg ha-1 every year (80-1), 40 Mg ha-1 every year (40-1) and 40 Mg ha-1 every four years (40-4). Results showed a decrease in soil pH values by increasing the amount of sewage sludge and a small alteration in the calcite structure particularly in 40-4. However, no significant differences between treatments were found in the total content of carbonates nor in the proportion of pedogenic carbonates. The high concentration of total carbonates in the soil (16.09 ± 0.48%), and of the proportion of pedogenic carbonates (40.21 ± 1.29%, assuming a δ13C of primary carbonates = 0 ‰) seemed elevated enough to compensate for the observed acidification in the studied soil. In the case of MF, no changes were observed in the pH values, nor in the carbonate content (total and pedogenic). This suggests that the use of sewage sludge could induce changes in the future at a faster rate and of greater dimension than the use of mineral fertilizers such as the ones used in this field (46% urea, superphosphate and ClK).
Open Access
250 km ultra long remote sensor system based on a fiber loop mirror interrogated by an OTDR
(Optical Society of America, 2011) Bravo Acha, Mikel; Baptista, José Manuel; Santos, José Luís; López-Amo Sáinz, Manuel; Frazão, Orlando; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A 253 km ultra long remote displacement sensor system based on a fiber loop mirror interrogated by a commercial OTDR is proposed and experimentally demonstrated. The use of a fiber loop mirror increases the signal to noise ratio allowing the system to interrogate sensors placed 253 km away from the monitoring system without using any optical amplification. The displacement sensor was based on a long period grating spliced inside of the loop mirror, which modifies the mirror reflectivity accordingly to the applied displacement.
Open Access
A 3-D indoor analysis of path loss modeling using kriging techniques
(IEEE, 2022) Diago Mosquera, Melissa; Aragón Zavala, Alejandro; Azpilicueta Fernández de las Heras, Leyre; Shubair, Raed M.; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This study proposes a novel measurement-based method to predict and model three-dimensional (3-D) path loss in indoor scenarios, which first regresses 28 GHz measurements via median path loss modeling and then includes ordinary Kriging to interpolate shadowing. The performance of this method is evaluated by investigating the spatial structure that follows shadowing through the semivariogram, covariance function, and correlogram as variography tools. It is shown that semivariogram outperforms the other statistics to describe shadowing spatial continuity in path loss modeling in terms of the mean absolute error.
Open Access
3-D printed horn antennas and components performance for space and telecommunications
(IEEE, 2018) Teniente Vallinas, Jorge; Iriarte Galarregui, Juan Carlos; Caballero Nagore, Rubén; Valcázar Berdofe, Daniel; Goñi, Mikel; Martínez, Aitor; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this work, a study of the performance of several antennas and components, manufactured using an accurate stereolithography 3D printer and resin for maximum accuracy and detail, is carried out. Electroless plating of the components to cover the pieces with a thick copper layer to improve their mechanical resistance is undertaken. Several SatCom horn antennas and components are designed, manufactured, and tested. A detailed study of a spline horn antenna and a filter is covered. These results are compared to the metallic lathe manufactured versions. Conclusions are derived from these tests, which are useful to improve additive manufactured components in future versions.