Exploring ways towards the excitation and amplification of surface plasmon-polaritons

On Driving plasmonic resonance THz graphena antennasWith the rapidly increasing demand for smaller and faster technology in the world of telecommunications over the past few years, there has come a time for nanotechnology to take over. Nanotechnology will provide with a new set of tools to the engineering community to design and manufacture nanoscale components with unprecedented functionalities. The ability to integrate several of those components into a single structure in just hundreds of nanometers will enable the development of new and advanced nanosystems. In this thesis, we go over the basics of nanoscale communications, the fundamentals of nanonetworks as well as the main state-of-the-art devices proposed to date. As the main focus of this work, two different alternatives to provide a signal source to an optical nanoscale communication system are proposed. First, as the optical term suggests, the basics of the most common light source are covered: the semiconductor laser. We describe its working principles and analyze its capabilities in order to determine its suitability for nanoscale communications. Last, a new concept of light source is proposed, which deals with light-matter interactions in the nanoscale: the plasmon nanolaser.Con la creciente demanda de dispositivos más inteligentes en el mundo de las telecomunicaciones en los últimos años, ha llegado la hora de hacer uso de la nanotecnología. La nanotecnología proporcionará un nuevo conjunto de herramientas para el sector de la ingeniería para diseñar y fabricar nano-dispositivos con funcionalidades sin precedentes. La habilidad de integrar múltiples componentes en una sola estructura en solo centenares de nanómetros permitirá el desarrollo de nuevos y avanzados nano-sistemas. En esta tesis, se presentan los fundamientos sobre las nano-comunicaciones, las nano-redes como también los componentes más avanzados que existen hoy en día. En concreto, en este trabajo se proponen dos alternativas sobre fuentes de señal para un sistema de nano-comunicaciones ópticas. En primer lugar se estudia la fuente de señal más común en comunicaciones ópticas: el láser semiconductor. Se analizan sus propiedades y características para determinar su idoneidad para integrarlo en un sistema de nano-comunicaciones ópticas. En segundo lugar, se propone otro tipo de fuente de luz, la cual se basa en interaciones de luz-materia en regiones cuánticas: el nano-láser plasmónico.Amb la creixent demanda de dispositius més intel·ligents en el món de les telecomunicacions en els darrers anys, ha arribat l'hora de fer ús de la nanotecnologia. La nanotecnologia proporcionarà un nou conjunt d'eines pel sector de l'enginyeria per dissenyar i fabricar nano-dispositius amb funcionalitats sense precedents. L'habilitat d'integrar diferents components en una sola estructura en només centenars de nanòmetres permetrà el desenvolupament de nous i avançats nano-sistemes. En aquesta tesi, es presenten els fonaments sobre les nano-comunicacions, les nano-xarxes com també els components més avançats que existeixen avui dia. En concret, en aquest treball es proposen dues alternatives sobre fonts de senyal per a un sistema de nano-comunicacions òptiques. En primer lloc s'estudia la font de senyal més comú a les comunicacions òptiques: el làser semiconductor. S'analitzen les seves propietats i característiques per determinar la seva idoneïtat per integrar-lo a un sistema de nano-comunicacions òptiques. En segon lloc, es proposa un altre tipus de font de llum, la qual es basa en interaccions de llum-matèria a regions quàntiques: el nano-làser plasmònic

Exploring ways towards the excitation and amplification of surface plasmon-polaritons

On Driving plasmonic resonance THz graphena antennasWith the rapidly increasing demand for smaller and faster technology in the world of telecommunications over the past few years, there has come a time for nanotechnology to take over. Nanotechnology will provide with a new set of tools to the engineering community to design and manufacture nanoscale components with unprecedented functionalities. The ability to integrate several of those components into a single structure in just hundreds of nanometers will enable the development of new and advanced nanosystems. In this thesis, we go over the basics of nanoscale communications, the fundamentals of nanonetworks as well as the main state-of-the-art devices proposed to date. As the main focus of this work, two different alternatives to provide a signal source to an optical nanoscale communication system are proposed. First, as the optical term suggests, the basics of the most common light source are covered: the semiconductor laser. We describe its working principles and analyze its capabilities in order to determine its suitability for nanoscale communications. Last, a new concept of light source is proposed, which deals with light-matter interactions in the nanoscale: the plasmon nanolaser.Con la creciente demanda de dispositivos más inteligentes en el mundo de las telecomunicaciones en los últimos años, ha llegado la hora de hacer uso de la nanotecnología. La nanotecnología proporcionará un nuevo conjunto de herramientas para el sector de la ingeniería para diseñar y fabricar nano-dispositivos con funcionalidades sin precedentes. La habilidad de integrar múltiples componentes en una sola estructura en solo centenares de nanómetros permitirá el desarrollo de nuevos y avanzados nano-sistemas. En esta tesis, se presentan los fundamientos sobre las nano-comunicaciones, las nano-redes como también los componentes más avanzados que existen hoy en día. En concreto, en este trabajo se proponen dos alternativas sobre fuentes de señal para un sistema de nano-comunicaciones ópticas. En primer lugar se estudia la fuente de señal más común en comunicaciones ópticas: el láser semiconductor. Se analizan sus propiedades y características para determinar su idoneidad para integrarlo en un sistema de nano-comunicaciones ópticas. En segundo lugar, se propone otro tipo de fuente de luz, la cual se basa en interaciones de luz-materia en regiones cuánticas: el nano-láser plasmónico.Amb la creixent demanda de dispositius més intel·ligents en el món de les telecomunicacions en els darrers anys, ha arribat l'hora de fer ús de la nanotecnologia. La nanotecnologia proporcionarà un nou conjunt d'eines pel sector de l'enginyeria per dissenyar i fabricar nano-dispositius amb funcionalitats sense precedents. L'habilitat d'integrar diferents components en una sola estructura en només centenars de nanòmetres permetrà el desenvolupament de nous i avançats nano-sistemes. En aquesta tesi, es presenten els fonaments sobre les nano-comunicacions, les nano-xarxes com també els components més avançats que existeixen avui dia. En concret, en aquest treball es proposen dues alternatives sobre fonts de senyal per a un sistema de nano-comunicacions òptiques. En primer lloc s'estudia la font de senyal més comú a les comunicacions òptiques: el làser semiconductor. S'analitzen les seves propietats i característiques per determinar la seva idoneïtat per integrar-lo a un sistema de nano-comunicacions òptiques. En segon lloc, es proposa un altre tipus de font de llum, la qual es basa en interaccions de llum-matèria a regions quàntiques: el nano-làser plasmònic

An urn model for majority voting in classification ensembles

In this work we analyze the class prediction of parallel randomized ensembles by majority voting as an urn model. For a given test instance, the ensemble can be viewed as an urn of marbles of different colors. A marble represents an individual classifier. Its color represents the class label prediction of the corresponding classifier. The sequential querying of classifiers in the ensemble can be seen as draws without replacement from the urn. An analysis of this classical urn model based on the hypergeometric distribution makes it possible to estimate the confidence on the outcome of majority voting when only a fraction of the individual predictions is known. These estimates can be used to speed up the prediction by the ensemble. Specifically, the aggregation of votes can be halted when the confidence in the final prediction is sufficiently high. If one assumes a uniform prior for the distribution of possible votes the analysis is shown to be equivalent to a previous one based on Dirichlet distributions. The advantage of the current approach is that prior knowledge on the possible vote outcomes can be readily incorporated in a Bayesian framework. We show how incorporating this type of problem-specific knowledge into the statistical analysis of majority voting leads to faster classification by the ensemble and allows us to estimate the expected average speed-up beforehandThe authors acknowledge financial support from the Comunidad de Madrid (project CASI-CAMCM S2013/ICE-2845), and from the Spanish Ministerio de Economía y Competitividad (projects TIN2013-42351-P and TIN2015-70308-REDT

A double pruning algorithm for classification ensembles

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-12127-2_11Proceedings of 9th International Workshop, MCS 2010, Cairo, Egypt, April 7-9, 2010.This article introduces a double pruning algorithm that can be used to reduce the storage requirements, speed-up the classification process and improve the performance of parallel ensembles. A key element in the design of the algorithm is the estimation of the class label that the ensemble assigns to a given test instance by polling only a fraction of its classifiers. Instead of applying this form of dynamical (instance-based) pruning to the original ensemble, we propose to apply it to a subset of classifiers selected using standard ensemble pruning techniques. The pruned subensemble is built by first modifying the order in which classifiers are aggregated in the ensemble and then selecting the first classifiers in the ordered sequence. Experiments in benchmark problems illustrate the improvements that can be obtained with this technique. Specifically, using a bagging ensemble of 101 CART trees as a starting point, only the 21 trees of the pruned ordered ensemble need to be stored in memory. Depending on the classification task, on average, only 5 to 12 of these 21 classifiers are queried to compute the predictions. The generalization performance achieved by this double pruning algorithm is similar to pruned ordered bagging and significantly better than standard bagging

Freshwater biodiversity loss in urbanised rivers

Since the second half of the 20th century, when monitoring programmes were implemented as a measure to improve the water quality of rivers, numerous advantages have been achieved. one of the most remarkable advances was the integration of bioindicators as a suitable and quick tool to complement the assessment based on the evaluation of physical and chemical parameters. This paper evaluated which of the already used water quality indices based on macroinvertebrates would be more suitable to assess the ecological status of 6 rivers (Barxas, Deva, Tea, Manco, Louro and Furnia rivers) within the Mino ˜ River international basin (NW Spain and N Portugal) applying the methodology proposed by the Water Framework Directive (WFD). In addition, the relationship between the water quality and the land uses within a buffer zone of 100 along the watershed of each river was studied. Our findings demonstrate that the IBMWP (Iberian Biomonitoring Working Party) is the most suitable index to evaluate the water quality of rivers from this geographical zone. Nevertheless it is necessary to use other more sensitive index like EPT and PT indices to identify any potential pressures that might be concealed by IBMWP. The tributaries of the Mino ˜ River generally presented a good ecological status according to the IBMWP. Nevertheless, the Louro River had the lowest score for all the indices being the worst preserved among all within the basin. On the contrary Barxas, Deva and Furnia rivers showed the higher values. The results indicated that the most urbanised river was the Louro River (13 %) followed, to a lesser extent, by Manco River (7 %) and Tea River (2 %). Consequently, the Louro River had the worst water quality (poor quality) and a less diverse benthic macroinvertebrate community, in which more generalist taxa such as Chironomids, Ceratopogonids, or Crustaceans were found. On the other hand, the rivers with the best water quality were the Barxas, Deva, and Furnia, all of them with a negligible proportion of artificial cover surface (<1 %) within the delimited buffer zone. This would suggest a negative influence of the proportion of artificial areas over diversity and quality indices.Universidade de Vigo/CISU

Hidden Markov Models for Activity Detection in Atrial Fibrillation Electrograms

Proceeding of 2020 Computing in Cardiology (CinC 2020), 13-16 September 2020, Rimini, ItalyActivity detection in atrial fibrillation (AF) electrograms (EGMs) is a key concept to understand the mechanisms of this frequent arrhythmia and design new strategies for its treatment. We present a new method that employs Hidden Markov Models (HMMs) to identify activity presence in bipolar EGMs. The method is fully unsupervised and hence it does not require labeled training data. The HMM activity detection method was validated and compared to the non-linear energy operator (NLEO) method for a set of manually annotated EGMs. The HMM performed better than the NLEO and exhibited more robustness in the presence of low voltage fragmented EGMs.This study was supported by grants PI18/01895 from the Instituto de Salud Carlos III, and RD16/0011/0029 Red de Terapia Celular from the Instituto de Salud Carlos III, the projects RTI2018-099655-B-I00; TEC2017-92552-EXP; PID2019-108539RB-C22, Y2018/TCS-4705, and the support of NVIDIA Corporation with the donation of the Titan V GPU used during this research.Publicad

Metal bashing: iron deficiency and manganese overexposure impact on peripheral nerves

Iron (Fe) deficiency (FeD) and manganese (Mn) overexposure (MnOE) may result in several neurological alterations in the nervous system. Iron deficiency produces unique neurological deficits due to its elemental role in central nervous system (CNS) development and myelination, which might persist after normalization of Fe in the diet. Conversely, MnOE is associated with diverse neurocognitive deficits. Despite these well-known neurotoxic effects on the CNS, the influence of FeD and MnOE on the peripheral nervous system (PNS) remains poorly understood. The aim of the present investigation was to examine the effects of developmental FeD and MnOE or their combination on the sciatic nerve of young and adult rats. The parameters measured included divalent metal transporter 1 (DMT1), transferrin receptor (TfR), myelin basic protein (MBP) and peripheral myelin protein 22 (PMP22) expression, as well as Fe levels in the nerve. Our results showed that FeD produced a significant reduction in MBP and PMP22 content at P29, which persisted at P60 after Fe-sufficient diet replenishment regardless of Mn exposure levels. At P60 MnOE significantly increased sciatic nerve Fe content and DMT1 expression. However, the combination of FeD and MnOE produced no marked motor skill impairment. Evidence indicates that FeD appears to hinder developmental peripheral myelination, while MnOE may directly alter Fe homeostasis. Further studies are required to elucidate the interplay between these pathological conditions.Fil: Amos Kroohs, Robyn M.. University of North Carolina; Estados UnidosFil: Usach, Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Piñero, Gonzalo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Vorhees, Charles V.. University of Cincinnati; Estados UnidosFil: Martínez Vivot, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Soto, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Williams, Michael T.. University of Cincinnati; Estados UnidosFil: Setton, Clara Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Validity evidence of the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) in Chile

El objetivo del estudio fue analizar la validez de la versión chilena de un instrumento para la identificación de diferentes niveles de riesgo asociado al consumo de alcohol, tabaco, marihuana y cocaína (Alcohol, Smoking and Substance Involvement Screening Test, ASSIST). Se evaluó la fiabilidad y consistencia del instrumento además de la validez concurrente y discriminante. La muestra fue de 400 usuarios de servicios de tratamiento drogas y alcohol ambulatorios y residenciales de la atención primaria de salud, comisarías y empresas. La consistencia interna obtenida fue alta (Alcohol α= .86. marihuana α= .84 y cocaína α= .90). El coeficiente de correlación intraclase (CCI) con la comparación test-retest fue buena para Alcohol (CCI = .66), marihuana (CCI = .74) y cocaína (CCI =.80). Se observó una buena correlación entre los puntajes del ASSIST el puntaje del AUDIT (r de Pearson = .85), ASI-Lite (r entre .66 y .83 para tabaco, alcohol, marihuana y cocaína) y SDS (r = .65). El punto de corte original para la detección del riesgo alto es de 27 puntos, sin embargo, considerando un mejor balance entre sensibilidad y especificidad se modificó ese corte a 21. Los resultados obtenidos en éste estudio demostraron las buenas propiedades psicométricas del ASSIST para la detección de distintos niveles de riesgo asociados al consumo de sustancias en población general de Chile.This study aims to psychometrically validate the Chilean version of the Alcohol, Smoking and Substance Involvement Screening Test ASSIST. Specifically, this study is interested in evaluating the reliability, consistency and concurrent and discriminant validity of this instrument. The sample was composed for a total of 400 people from four different settings: treatment centers (residential and ambulatories), primary health care, police stations and companies. The reliability of the ASSIST was high (α = .86 for Alcohol, α = .84 for marijuana and α = .90 for cocaine). The intra class correlation coefficient (ICC) with test-retest comparison was statistically significant for Alcohol (ICC = .66), marijuana (ICC = .74) and cocaine (ICC = .80). There were statistically significant correlations between the ASSIST and the AUDIT score (Pearson?s r = .85), the ASSIST and the ASI-Lite score (r between .66 and .83 for tobacco, alcohol, marijuana and cocaine), and the ASSIST and the SDS score (r = .65). The original cutoff point for high risk detection was 27 points, however, in order to have a better balance between sensitivity and specificity the cut was changed to 21 points. The ASSIST presents good psychometric properties and therefore is a reliable and valid instrument to be used as a mechanism to detect risk levels of substance use in the Chilean population.Fil: Soto Brandt, Gonzalo. Servicio Nacional para la Prevención y Rehabilitación del Consumo de Drogas y Alcohol; ChileFil: Portilla Huidobro, Rodrigo. Servicio Nacional para la Prevención y Rehabilitación del Consumo de Drogas y Alcohol; ChileFil: Huepe Artigas, David. Universidad Diego Portales; ChileFil: Rivera Rei, Álvaro. Universidad Diego Portales; ChileFil: Escobar, María Josefina. Universidad Diego Portales; ChileFil: Salas Guzmán, Natalia. Universidad Diego Portales; ChileFil: Canales Johnson, Andrés. Universidad Diego Portales; ChileFil: Ibáñez Barassi, Agustín Mariano. Universidad Diego Portales; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martínez Guzmán, Claudio. Universidad Diego Portales; ChileFil: Castillo Carniglia, Álvaro. Servicio Nacional para la Prevención y Rehabilitación del Consumo de Drogas y Alcohol; Chil

Differences in corneo-scleral topographic profile between healthy and keratoconus corneas

Purpose: To evaluate the differences in corneo-scleral topographic profile between healthy and keratoconus eyes, and their potential diagnostic ability for keratoconus detection. Methods: Prospective comparative study including 21 keratoconic eyes (11 patients) and 88 healthy eyes (88 patients). In all cases, a complete eye exam was performed including an evaluation of the corneo-scleral profile. The diagnostic ability of corneo-scleral topographic parameters to detect keratoconus was evaluated using the receiver operating characteristic (ROC) curve. Results: A significant lower inferior tangent angle at limbus (ITA) was found in the keratoconic group compared to the control group (p = 0.024). Regarding sagittal heights, significant differences between groups were found in temporal sagittal height (TSH) for 11 mm (p = 0.040), 12 mm (p = 0.041) and 13 mm corneal chords (p = 0.040), difference between temporal and nasal sagittal heights (T-NSH) for 12 mm (p = 0.025) and 13 mm (p = 0.034), and maximum sagittal height (MaxSH) for 12 mm (p = 0.043), with higher values in keratoconus. In bilateral cases, these differences were not found when comparing with the least severe keratoconus eye. Statistical significance for the ROC curve was only found for ITA (p = 0.025), 12-mm (p = 0.048) and 13-mm TSH (p = 0.042), and 13-mm T-NSH (p = 0.037), with cutoff values associated to limited values of sensitivity and specificity. Conclusions: The corneo-scleral profile in keratoconus presents higher levels of asymmetry compared to healthy eyes, especially in eyes with moderate and advanced stages of the disease. The diagnostic accuracy of corneo-scleral topographic data alone for keratoconus detection is limited and must be used in conjunction with other clinical parameters