766 research outputs found
Reduction of Uncertainty Propagation in the Airport Operations Network
[EN] Airport operations are a complex system involving multiple elements (ground access, landside, airside and airspace), stakeholders (ANS providers, airlines, airport managers, policy makers and ground handling companies) and interrelated processes. To ensure appropriate and safe operation it is necessary to understand these complex relationships and how the effects of potential incidents, failures and delays (due to unexpected events or capacity constraints) may propagate throughout the different stages of the system. An incident may easily ripple through the network and affect the operation of the airport as a whole, making the entire system vulnerable. A holistic view of the processes that also takes all of the parties (and the connections between them) into account would significantly reduce the risks associated with airport operations, while at the same time improving efficiency. Therefore, this paper proposes a framework to integrate all relevant stakeholders and reduce uncertainty in delay propagation, thereby lowering the cause-effect chain probability of the airport system (which is crucial for the operation and development of air transport). Firstly, we developed a model (map) to identify the functional relationships and interdependencies between the different stakeholders and processes that make up the airport operations network. This will act as a conceptual framework. Secondly, we reviewed and characterised the main causes of delay. Finally, we extended the system map to create a probabilistic graphical model, using a Bayesian Network approach and influence diagrams, in order to predict the propagation of unexpected delays across the airport operations network. This will enable us to learn how potential incidents may spread throughout the network creating unreliable, uncertain system states. Policy makers, regulators and airport managers may use this conceptual framework (and the associated indicators) to understand how delays propagate across the airport network, thereby enabling them to reduce system vulnerability, and increase its robustness and efficiency.Rodríguez Sanz, Á.; Gómez Comendador, F.; Arnaldo Valdés, R. (2016). Reduction of Uncertainty Propagation in the Airport Operations Network. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 36-78. https://doi.org/10.4995/CIT2016.2016.3484OCS367
Uncertainty management at the airport transit view
Air traffic networks, where airports are the nodes that interconnect the entire system, have a time-varying and stochastic nature. An incident in the airport environment may easily propagate through the network and generate system-level effects. This paper analyses the aircraft flow through the Airport Transit View framework, focusing on the airspace/airside integrated operations. In this analysis, we use a dynamic spatial boundary associated with the Extended Terminal Manoeuvring Area concept. Aircraft operations are characterised by different temporal milestones, which arise from the combination of a Business Process Model for the aircraft flow and the Airport Collaborative Decision-Making methodology. Relationships between factors influencing aircraft processes are evaluated to create a probabilistic graphical model, using a Bayesian network approach. This model manages uncertainty and increases predictability, hence improving the system's robustness. The methodology is validated through a case study at the Adolfo Suárez Madrid-Barajas Airport, through the collection of nearly 34,000 turnaround operations. We present several lessons learned regarding delay propagation, time saturation, uncertainty precursors and system recovery. The contribution of the paper is two-fold: it presents a novel methodological approach for tackling uncertainty when linking inbound and outbound flights and it also provides insight on the interdependencies among factors driving performance
Event-related potentials associated to N-back test performance in schizophrenia
Producción CientíficaMapping of Event-Related Potentials (ERP) associated with auditory and visual odd-ball paradigms has shown consistent differences between healthy controls and schizophrenia patients. It may be hypothesized that higher task attentional/cognitive demand will result in larger differences in these paradigms, which may help understanding the substrates of cognitive deficits in this syndrome. To this aim, we performed an EEG study comparing the effects of increasing the attentional/cognitive load of an auditory N-back task on the Event-Related Potential in 50 subjects with schizophrenia (11 first episodes) and 35 healthy controls. We considered a post-target window of 1000 ms to explore possible between groups differences in N100, P300, and Late Slow Wave (LSW), and compared these components between 0-back (‘lower attentional/cognitive load) and 1-back (‘higher attentional/cognitive load’) conditions. Our results showed that N100 and LSW amplitude increase from 0- to 1-back condition was significantly larger in healthy controls compared to schizophrenia patients. Furthermore, LSW amplitude difference between 0- and 1-back conditions positively correlated with performance in the behavioral cognitive assessment. Taken together, these results support that higher task attentional/cognitive load (0-back vs. 1-back condition) increase N100 amplitude differences and reveal new findings related to the LSW component in schizophrenia.Junta de Castilla y León (project VA057P17)Instituto de Salud Carlos III (project PI18/00178
Urban life promotes delayed dispersal and family living in a non‑social bird species
In some vertebrate species, family units are typically formed when sexually mature individuals delay
dispersal and independent breeding to remain as subordinates in a breeding group. This behaviour
has been intensively studied in gregarious species but has also been described in non-social species
where ecological and evolutionary drivers are less known. Here, we explore factors that favour
delayed dispersal and family living and potential benefts associated with this strategy in a non-social,
monogamous species (the burrowing owl, Athene cunicularia) occupying urban and rural habitats. Our
results show that family units arise when frst-year individuals, mainly males, delay their dispersal to
stay in their natal nests with their parents. This delayed dispersal, while still uncommon, was more
prevalent in urban (7%) than in rural (3%) habitats, and in areas with high conspecifc density and
productivity. Birds delaying dispersal contributed to the genetic pool of the ofspring in 25% of the
families analysed, but did not increase the productivity of the nests where they remained. However,
their presence was related to an improvement in the body condition of chicks, which was ultimately
linked to a slightly positive efect in ofspring future survival probabilities. Finally, delayed dispersers
were recruited as breeders in high-quality urban territories and closer to their natal nests than
individuals dispersing during their frst year of life. Thus, our results suggest that delaying dispersal
may be mainly related to opportunities to inheriting a good quality territory, especially for males. Our
study contributes to understanding the role played by habitat quality in promoting delayed dispersal
and family living, not only in social but also non-social species, highlighting its impact in the ecology
and evolution of animal populationsPeer reviewe
Formar y evaluar competencias en educación superior: una experiencia sobre inclusión digital
Digital inclusion, understood from a pedagogical perspective, is to improve teaching-learning processes by making them more accessible to all students using digital technologies. However, despite its relevance, we can observe that neither the academic regulations nor the different specialised frameworks specify how to apply it in the classroom. In order to address this problem, we present a competence-based evaluation process (related to digital inclusion) carried out during a training experience using the service-learning teaching methodology, in which university students, practising early childhood and primary school teachers and teaching staff from the Rovira i Virgili University participated. The results, which were obtained by means of a questionnaire constructed from the COMDID standard and the analysis of the evidence of learning provided by the students, show how the students overvalue themselves in the self-assessments, while the university teaching staff give them a lower score in each of the five descriptors analysed. In conclusion, it was found that competency-based assessment processes involving different assessors are more complex to implement but are more objective as they involve different points of view that would not be possible with a single point of view. Furthermore, it was found that the digital resources most used by students to present their evidence of learning were the least difficult for teachers to assess, and conversely.La inclusión digital, entendida desde la perspectiva pedagógica, tiene como propósito mejorar los procesos de enseñanza-aprendizaje, haciéndolos, gracias al uso de las tecnologías digitales, más accesibles al conjunto del alumnado. Pero a pesar de su relevancia, podemos observar que ni la normativa académica ni los diferentes marcos especializados concretan como aplicarla en el aula. Con la intención de abordar esta problemática, se presenta un proceso de evaluación por competencias (relacionadas con la inclusión digital) llevado a cabo durante una experiencia formativa vehiculada a través de la metodología didáctica del aprendizaje-servicio, en la que participó alumnado universitario, docentes de educación infantil y primaria en ejercicio y profesorado de la Universitat Rovira i Virgili. Los resultados, que se obtuvieron mediante un cuestionario construido a partir del estándar COMDID y el análisis de las evidencias de aprendizaje proporcionadas por los/las estudiantes, muestran cómo el alumnado se sobrevalora en las autoevaluaciones, mientras que el profesorado universitario le otorga una puntuación más baja en cada uno de los cinco descriptores analizados. Como conclusión, se ha podido comprobar que los procesos de evaluación por competencias en los que participan diferentes agentes evaluadores son más complejos a la hora de ser implementados, pero se revisten de mayor objetividad al contar con diferentes puntos de vista que no serían posibles con una única mirada. Además, se ha constatado que los recursos digitales más utilizados por el alumnado para presentar sus evidencias de aprendizaje fueron los que menos dificultad revistieron al profesorado al ser evaluados, y a la inversa
Asociación de superficies limitadoras de obstáculos y franjas de pista
En el presente se analiza la asociación de las SLOs con la franja de pista, superficies de aproximación, superficies de transición entre otros elementos y algunos interrogantes sobre la necesidad o no de esta asociación. La seguridad operacional puede ser analizada a través del SMS, del SSP, mediante matrices de riesgo, estudios de evaluación de seguridad operacional, estudios de compatibilidad, estudios aeronáuticos o bien, mediante la aplicación del Anexo 14 Lo anterior es analizado observando las características de las SLOs a través de las diferentes ediciones del Anexo 14 (desde la tercera hasta la octava edición y la propuesta de modificación de 2020). En la edición vigente del Anexo 14, se observan cambios relacionados con parámetros de diseño sobre la base de un cambio de conceptos respecto a la clave de referencia de aeródromo que se tenía. Los obstáculos que se analiza por medio de superficies limitadoras de obstáculos sigue permaneciendo, casi sin alteración, salvo por, la modificación de algunas dimensiones que son producto del cambio de dimensiones de la franja de pista. Al modificar las dimensiones de franjas de pista, se han modificado como consecuencia los bordes internos de las superficies que en teorías están asociados a la misma. La contribución es un análisis de dicha asociación.Grupo de Transporte Aéreo - Grupo de Ingeniería Aplicada a la Industri
Asociación de superficies limitadoras de obstáculos y franjas de pista
En el presente se analiza la asociación de las SLOs con la franja de pista, superficies de aproximación, superficies de transición entre otros elementos y algunos interrogantes sobre la necesidad o no de esta asociación. La seguridad operacional puede ser analizada a través del SMS, del SSP, mediante matrices de riesgo, estudios de evaluación de seguridad operacional, estudios de compatibilidad, estudios aeronáuticos o bien, mediante la aplicación del Anexo 14 Lo anterior es analizado observando las características de las SLOs a través de las diferentes ediciones del Anexo 14 (desde la tercera hasta la octava edición y la propuesta de modificación de 2020). En la edición vigente del Anexo 14, se observan cambios relacionados con parámetros de diseño sobre la base de un cambio de conceptos respecto a la clave de referencia de aeródromo que se tenía. Los obstáculos que se analiza por medio de superficies limitadoras de obstáculos sigue permaneciendo, casi sin alteración, salvo por, la modificación de algunas dimensiones que son producto del cambio de dimensiones de la franja de pista. Al modificar las dimensiones de franjas de pista, se han modificado como consecuencia los bordes internos de las superficies que en teorías están asociados a la misma. La contribución es un análisis de dicha asociación.Grupo de Transporte Aéreo - Grupo de Ingeniería Aplicada a la Industri
Asociación de superficies limitadoras de obstáculos y franjas de pista
En el presente se analiza la asociación de las SLOs con la franja de pista, superficies de aproximación, superficies de transición entre otros elementos y algunos interrogantes sobre la necesidad o no de esta asociación. La seguridad operacional puede ser analizada a través del SMS, del SSP, mediante matrices de riesgo, estudios de evaluación de seguridad operacional, estudios de compatibilidad, estudios aeronáuticos o bien, mediante la aplicación del Anexo 14 Lo anterior es analizado observando las características de las SLOs a través de las diferentes ediciones del Anexo 14 (desde la tercera hasta la octava edición y la propuesta de modificación de 2020). En la edición vigente del Anexo 14, se observan cambios relacionados con parámetros de diseño sobre la base de un cambio de conceptos respecto a la clave de referencia de aeródromo que se tenía. Los obstáculos que se analiza por medio de superficies limitadoras de obstáculos sigue permaneciendo, casi sin alteración, salvo por, la modificación de algunas dimensiones que son producto del cambio de dimensiones de la franja de pista. Al modificar las dimensiones de franjas de pista, se han modificado como consecuencia los bordes internos de las superficies que en teorías están asociados a la misma. La contribución es un análisis de dicha asociación.Grupo de Transporte Aéreo - Grupo de Ingeniería Aplicada a la Industri
Relation between EEG resting-state power and modulation of P300 task-related activity in theta band in schizophrenia
Producción CientíficaThere is some consistency in previous EEG findings that patients with schizophrenia have increased resting-state cortical activity. Furthermore, in previous work, we have provided evidence that there is a deficit in the modulation of bioelectrical activity during the performance of a P300 task in schizophrenia. Our hypothesis here is that a basal hyperactivation would be related with altered ability to change or modulate cortical activity during a cognitive task. However, no study so far, to the best of our knowledge, has studied the association between resting-state activity and task-related modulation. With this aim, we used a dual EEG paradigm (resting state and oddball task for elicitation of the P300 evoked potential) in a sample of patients with schizophrenia (n = 100), which included a subgroup of patients with first episode psychosis (n = 30), as well as a group of healthy controls (n = 93). The study measures were absolute power for resting-state; and spectral entropy (SE) and connectivity strength (CS) for P300-task data, whose modulation had been previously found to be altered in schizophrenia. Following the literature on P300, we focused our study on the theta frequency band. As expected, our results showed an increase in resting state activity and altered task-related modulation. Moreover, we found an inverse relationship between the amount of resting-state activity and modulation of task-related activity. Our results confirm our hypothesis and support the idea that a greater amount of resting theta-band synchrony could hamper the modulation of signal regularity (quantified by SE) and activity density (measured by CS) during the P300 task performance. This association was found in both patients and controls, suggesting the existence of a common mechanism and a possible ceiling effect in schizophrenia patients in relation to a decreased inhibitory function that limits their cortical reactivity to the task
High-Throughput Mass Measurement Of Single Bacterial Cells By Silicon Nitride Membrane Resonators
Trabajo presentado en la 36th International Conference on Micro Electro Mechanical Systems (MEMS), celebrada en Munich (Alemania), del 15 al 19 de enero de 2023.© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.We present a technological approach to precisely measure the dry mass of many individual cells of a bacteria colony. In this technique, bacteria are transported from aqueous solution into gas phase and subsequently guided to the surface of a silicon nitride membrane resonator. Abrupt downshifts in the membrane eigenfrequencies are measured upon every bacterium adhesion and are related to the dry mass of the cell by theoretical methods. We measure the dry mass of Escherichia coli K-12 and Staphylococcus epidermidis with an unprecedented throughput of 20 cells/min and with a mass resolution of ⁓1%. Finally, we apply the Koch & Schaechter model to assess the intrinsic sources of growth stochasticity.This work was supported by the European Union’s
Horizon 2020 Research and Innovation Program under
Grant Agreement No. 731868-VIRUSCAN and by the
ERC CoG Grant 681275 “LIQUIDMASS”. We
acknowledge the service from the Micro and
Nanofabrication Laboratory an X-SEM laboratory at IMNCNM
funded by the Comunidad de Madrid (Project
S2018/NMT-4291 TEC2SPACE) and by MINECO
(Project CSIC12-4E-1794 with support from FEDER,
FSE). E. G. S. acknowledges financial support by the
Spanish Science and Innovation Ministry through Ramón
y Cajal grant RYC-2019-026626-I
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