The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR, browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters. Finally we briefly discuss on the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, and touch on communication and outreach activities, the consortium organisation, and finally on the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental Astronomy with minor editin

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory. Athena is a versatile observatory designed to address the Hot and Energetic Universe science theme, as selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), X-IFU aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over a hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR (i.e. in the course of its preliminary definition phase, so-called B1), browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters, such as the instrument efficiency, spectral resolution, energy scale knowledge, count rate capability, non X-ray background and target of opportunity efficiency. Finally, we briefly discuss the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, touch on communication and outreach activities, the consortium organisation and the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with ESA member state contributions from Belgium, Czech Republic, Finland, Germany, Poland, Spain, Switzerland, with additional contributions from the United States and Japan.The French contribution to X-IFU is funded by CNES, CNRS and CEA. This work has been also supported by ASI (Italian Space Agency) through the Contract 2019-27-HH.0, and by the ESA (European Space Agency) Core Technology Program (CTP) Contract No. 4000114932/15/NL/BW and the AREMBES - ESA CTP No.4000116655/16/NL/BW. This publication is part of grant RTI2018-096686-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This publication is part of grant RTI2018-096686-B-C21 and PID2020-115325GB-C31 funded by MCIN/AEI/10.13039/501100011033

Desarrollo y aplicación de modelo de simulación basada en agentes a gran escala para la ciudad de Santiago

Magíster en Ciencias de la Ingeniería, Mención Transporte. Ingeniero CivilLa evaluación de políticas de transporte requiere de herramientas que permitan predecir cómo reaccionarán los usuarios del sistema frente a diversos estímulos. El objetivo de este trabajo es el desarrollo y aplicación de una nueva forma de modelar al sistema de transporte de la ciudad de Santiago de Chile en donde cada usuario es representado por un objeto denominado agente que utiliza la infraestructura vial existente e interactúa con los demás a través de simulación. El modelo utilizado en esta ocasión es MATSim, el cual hace uso de una base de datos denominada escenario que contiene la información del sistema de transporte y características de las personas del área de estudio. El trabajo se dividió en tres etapas secuenciales: mejoramientos al escenario básico desarrollado originalmente por Kickhöfer et al. (2016), calibración de los escenarios mejorados y finalmente aplicación de éstos para la evaluación de esquemas de tarificación por congestión de tipo cordón. En la primera etapa, la población sintética fue mejorada a través de técnicas de relativa sencillez, utilizando datos públicamente disponibles. En ella, se aumentó el tamaño de la población de forma que representara a un 1% y 10% del total, y se agrego variabilidad a los horarios de inicio de los viajes y localización de las actividades de los agentes. Finalmente, se incluyeron las tarifas de las autopistas concesionadas, lo que está asociado a características de la red del escenario. El principal aporte de esta etapa es el dejar públicamente disponible un escenario que, si bien resulta ser más cercano a la realidad en términos de sus inputs, sirva como punto de partida para continuar con futuros desarrollos. Posteriormente, en la segunda etapa ambos escenarios mejorados (1% y 10 %) fueron calibrados con una metodología ad-hoc, con el objetivo de contar con escenarios útiles para evaluar políticas de transporte. En ésta, se demuestran las ventajas y desventajas de dicha metodología, en conjunto con el efecto del escalamiento en los indicadores analizados durante el proceso de calibración, encontrándose que tanto la evolución del puntaje promedio en las simulaciones sin re-planificación como los tiempos de viajes por kilómetro se ven afectados por dicha técnica. Finalmente, se incluyeron dos esquemas de tarificación de tipo cordón a los escenarios, con el objetivo de demostrar la utilidad de este enfoque de modelación y cuyos resultados se compararon de manera ilustrativa con aquellos obtenidos con el modelo estático ESTRAUS. De manera general, se observa que ambos escenarios muestran sensibilidades distintas con respecto a los esquemas de tarificación. En conjunto con esto, se encuentra que los escenarios de MATSim poseen variaciones porcentuales mayores en todos los indicadores analizados con respecto a sus análogos encontrados con ESTRAUS

Doença da descompressão no mergulho recreativo com ar comprimido

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2017O mergulho recreativo com ar comprimido tem visto o seu número de praticantes au-mentar nos últimos anos. Embora seja uma atividade segura praticada por entre 3 a 6 milhões de pessoas em todo o mundo, existem riscos decorrentes das pressões elevadas a que o mergulhador é exposto durante o mergulho. Um desses riscos é a Doença da Des-compressão. Este trabalho procura explicar de forma clara e atualizada quais os mecanismos fisio-patológicos por detrás da Doença da Descompressão, quais as suas formas de apresenta-ção e como é que se faz o diagnóstico diferencial entre esta doença e outras que se mani-festam de forma semelhante, como a embolia gasosa arterial e o barotrauma do ouvido interno. É também abordado o tratamento da doença com oxigénio hiperbárico e a forma como esta e outras doenças resultantes da prática do mergulho podem ser prevenidas atra-vés de normas estabelecidas a nível internacional pelas principais agências de mergulho.Recreational SCUBA diving has seen its number of practitioners increase in recent years. Although it is a safe activity practised by 3 to 6 million people worldwide, there are risks arising from the high pressures the diver is subjected to during diving. One such risk is Decompression Sickness. This paper aims to explain in a clear and updated way the pathophysiological mechanisms behind Decompression Sickness, its clinical presentation and how the differential diagnosis between this disease and others that present themselves with similar symptoms, such as arterial gas embolism and inner ear barotrauma, can be done. Treatment of the disease with hyperbaric oxygen is also addressed, as well as prevention of this and other diseases resulting from diving through international norms established by the major diving agencies

Mechanisms controlling motor output to a transfer hand after learning a sequential pinch force skill with the opposite hand

Objective: Training to perform a serial reaction-time task (procedural motor learning) with one hand results in performance improvements in the untrained as well as in the trained hand, a phenomenon referred to as intermanual transfer. The aim of this study was to investigate the neurophysiological changes associated with intermanual transfer associated with learning to perform an eminently different task involving fine force control within the primary motor cortex (M1). We hypothesized that intermanual transfer of learning Such a task would reveal intracortical changes within M1. Methods: Speed (time to complete each sequence) and accuracy (% of accuracy errors) of motor performance were measured in both hands before and after right (dominant) hand practice. Transcranial magnetic stimulation (TMS) was used to characterize recruitment curves (RC), short intracortical inhibition (SICI), intracortical facilitation (ICF) and interhemispheric inhibition (IHI) from the left to the right M1. Results: Practice resulted in significant improvements in both speed and accuracy in the right trained hand and in the left untrained hand. RC increased in the left M1, SICI decreased in both M1s, and IHI from the left to the right M1 decreased. No changes were identified in ICF nor in RC in the right M1. Conclusions: Our results suggest that some neurophysiological mechanisms operating in the M1 controlling performance of an untrained hand may contribute to optimize the procedure for selecting and implementing correct pinch force levels. Significance: These results raise the hypothesis of a contribution of modulation of SICI and IHI, or an interaction between both to intermanual transfer after learning a sequential pinch force task. (C) 2009 Published by Elsevier Ireland Ltd. on behalf of International Federation of Clinical Neurophysiology

Improvement of spatial tactile acuity by transcranial direct current stimulation.

Non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) has been successfully used to induce polarity-specific excitability changes in the brain. However, it is still unknown if anodal tDCS (tDCS(anodal)) applied to the primary somatosensory cortex (S1) can lead to behavioral changes in performance of tactile discriminative tasks

Modulation of Effects of Intermittent Theta Burst Stimulation Applied Over Primary Motor Cortex (M1) by Conditioning Stimulation of the Opposite M1

The excitability of the human primary motor cortex (M1) as tested with transcranial magnetic stimulation (TMS) depends on its previous history of neural activity. Homeostatic plasticity might be one important physiological mechanism for the regulation of corticospinal excitability and synaptic plasticity. Although homeostatic plasticity has been demonstrated locally within M1, it is not known whether priming M1 could result in similar homeostatic effects in the homologous M1 of the opposite hemisphere. Here, we sought to determine whether down-regulating excitability (priming) in the right (R) M1 with 1-Hz repetitive transcranial magnetic stimulation (rTMS) changes the excitability-enhancing effect of intermittent theta burst stimulation (iTBS) applied over the homologous left (L) M1. Subjects were randomly allocated to one of four experimental groups in a sham-controlled parallel design with real or sham R M1 1-Hz TMS stimulation always preceding L M1 iTBS or sham by about 10 min. The primary outcome measure was corticospinal excitability in the L M1, as measured by recruitment curves (RCs). Secondary outcome measures included pinch force, simple reaction time, and tapping speed assessed in the right hand. The main finding of this study was that preconditioning R M1 with 1-Hz rTMS significantly decreased the excitability-enhancing effects of subsequent L M1 iTBS on RCs. Application of 1-Hz rTMS over R M1 alone and iTBS over L M1 alone resulted in increased RC in L M1 relative to sham interventions. The present findings are consistent with the hypothesis that homeostatic mechanisms operating across hemispheric boundaries contribute to regulate motor cortical function in the primary motor cortex

Anteproyecto de una prensa hidraulica de uso multiple

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A FPGA-based fast converging digital adaptive filter for real time RFI mitigation on ground based radio telescopes

Radio Frequency Interference (RFI) is a growing concern in the radio astronomy community. Single-dish telescopes are particularly susceptible to RFI. Several methods have been developed to cope with RF-polluted environments, based on flagging, excision, and real-time blanking, among others. All these methods produce some degree of data loss or require assumptions to be made on the astronomical signal. We report the development of a real-time, digital adaptive filter implemented on a Field Programmable Gate Array (FPGA) capable of processing 4096 spectral channels in a 1 GHz of instantaneous bandwidth. The filter is able to cancel a broad range of interference signals and quickly adapt to changes on the RFI source, minimizing the data loss without any assumption on the astronomical or interfering signal properties. The speed of convergence (for a decrease to a 1%) was measured to be 208.1 mu s for a broadband noise-like RFI signal and 125.5 mu s for a multiple-carrier RFI signal recorded at the FAST radio telescope.Chilean National Commission for Scientific and Technological Research (CONICYT) CATA-Basal PFB06 ALMA 31150012 FONDECYT 11140428 Chinese Academy of Science South America Center for Astronomy (CASSACA) Chinese Academy of Sciences 114A11-KYSB2016000