196 research outputs found

    A wearable closed-loop insulin delivery system based on low-power SoCs

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    The number of patients living with diabetes has increased significantly in recent years due to several factors. Many of these patients are choosing to use insulin pumps for their treatment, artificial systems that administer their insulin and consist of a glucometer and an automatic insulin supply working in an open loop. Currently, only a few closed-loop insulin delivery devices are commercially available. The most widespread systems among patients are what have been called the “Do-It-Yourself Hybrid Closed-Loop systems.” These systems require the use of platforms with high computing power. In this paper, we will present a novel wearable system for insulin delivery that reduces the energy and computing consumption of the platform without affecting the computation requirements. Patients’ information is obtained from a commercial continuous glucose sensor and a commercial insulin pump operating in a conventional manner. An ad-hoc embedded system will connect with the pump and the sensor to collect the glucose data and process it. That connection is accomplished through a radiofrequency channel that provides a suitable system for the patient. Thus, this system does not require to be connected to any other processor, which increases the overall stability. Using parameters configured by the patient, the control system will make automatic adjustments in the basal insulin infusion thereby bringing the patient’s glycaemia to the target set by a doctor’s prescription. The results obtained will be satisfactory as long as the configured parameters faithfully match the specific characteristics of the patient. Results from the simulation of 30 virtual patients (10 adolescents, 10 adults, and 10 children), using a python implementation of the FDA-approved (Food and Drug Administration) UVa (University of Virginia)/Padova Simulator and a python implementation of the proposed algorithm, are presented

    Loss of pancreas upon activated Wnt signaling is concomitant with emergence of gastrointestinal identity

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    Organ formation is achieved through the complex interplay between signaling pathways and transcriptional cascades. The canonical Wnt signaling pathway plays multiple roles during embryonic development including patterning, proliferation and differentiation in distinct tissues. Previous studies have established the importance of this pathway at multiple stages of pancreas formation as well as in postnatal organ function and homeostasis. In mice, gain-of-function experiments have demonstrated that activation of the canonical Wnt pathway results in pancreatic hypoplasia, a phenomenon whose underlying mechanisms remains to be elucidated. Here, we show that ectopic activation of epithelial canonical Wnt signaling causes aberrant induction of gastric and intestinal markers both in the pancreatic epithelium and mesenchyme, leading to the development of gut-like features. Furthermore, we provide evidence that ÎČ -catenin-induced impairment of pancreas formation depends on Hedgehog signaling. Together, our data emphasize the developmental plasticity of pancreatic progenitors and further underscore the key role of precise regulation of signaling pathways to maintain appropriate organ boundaries

    The controllability of a monetary aggregate in EMU

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    La consideracion de un agregado monetario como objetivo intermedio de la politica monetaria exige que esa definicion de liquidez mantenga una relacion de estabilidad con el objetivo final y que su evolucion pueda ser controlada por parte del banco central. Este documento analiza esta segunda cuestion, centrandose en las posibilidades que tendria el Banco Central Europeo de controlar efectivamente un agregado monetario si decidiera considerarlo como objetivo intermedio. En el trabajo se revisan los mecanismos a traves de los cuales la politica monetaria puede controlar la evolucion de la cantidad de dinero, y se examinan las propiedades empiricas de la demanda de dinero en la Union Monetaria Europea (UME) y en un pais, como Alemania, en el que se han venido fijando objetivos en terminos de un agregado monetario. El documento pone de manifiesto que las condiciones para ejercer un control adecuado de la cantidad de dinero en la UME son notablemente mas desfavorables de lo que resultan en Alemania. (ac) (jle) (em) (jp) (mac

    Accuracy and precision of agents orientation in an indoor positioning system using multiple infrastructure lighting spotlights and a PSD sensor

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    In indoor localization there are applications in which the orientation of the agent to be located is as important as knowing the position. In this paper we present the results of the orientation estimation from a local positioning system based on position-sensitive device (PSD) sensors and the visible light emitted from the illumination of the room in which it is located. The orientation estimation will require that the PSD sensor receives signal from either 2 or 4 light sources simultaneously. As will be shown in the article, the error determining the rotation angle of the agent with the on-board sensor is less than 0.2 degrees for two emitters. On the other hand, by using 4 light sources the three Euler rotation angles are determined, with mean errors in the measurements smaller than 0.35◩ for the x- and y-axis and 0.16◩ for the z-axis. The accuracy of the measurement has been evaluated experimentally in a 2.5 m-high ceiling room over an area of 2.2 m2 using geodetic measurement tools to establish the reference ground truth values.Junta de Comunidades de Castilla-La Manch

    Analysis of Multiple-Access Discrimination Techniques for the Development of a PSD-Based VLP System

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    There are several technologies and techniques available when developing indoor positioning systems (IPS). Recently, the development of positioning systems based on optical signals has aroused great interest, mainly those using visible light from the lighting infrastructure. In this work, we analyze which techniques give better results to lay the foundations for the development of a Visible Light Positioning system (VLP). Working only with a receiver, it is analyzed what the result of determining the position of different emitters is when they emit simultaneously and without any synchronism. The results obtained by Frequency Division Multiple Access (FDMA) (with digital bandpass filters, I/Q demodulation, and FFT) and Code Division Multiple Access (CDMA) are compared. The interference between signals when emitted simultaneously from multiple emitters is analyzed as well as the errors they cause and how these effects can be mitigated. As a result of the research, the advantages and disadvantages using different multiple-access determination techniques are determined. In addition, advantages and disadvantages of using FDMA and CDMA techniques as well as hardware requirements that make one more feasible than the other are presented. The system behavior, in terms of errors, is established using FDMA and different configurations such as: I/Q, RMS, or FFT. The work also determines the error rates that can be obtained with the different FDMA and CDMA configurations, considering different error scenarios and integration time. Synthetic emulations and empirical tests were performed, which concluded that IPS systems based on optical signals and PSD sensors can achieve very high measurement accuracies and a high measurement rate. Obtained positioning errors in a room of 3 m height are less than 1 cm when working in noisy environments.Agencia Estatal de InvestigaciĂł

    Tropospheric water vapour and relative humidity profiles from lidar and microwave radiometry

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    In this paper, we outline an iterative method to calibrate the water vapour mixing ratio profiles retrieved from Raman lidar measurements. Simultaneous and co-located radiosonde data are used for this purpose and the calibration results obtained during a radiosonde campaign in summer and autumn 2011 are presented. The water vapour profiles measured during night-time by the Raman lidar and radiosondes are compared and the differences between the methodologies are discussed. Then, a new approach to obtain relative humidity profiles by combination of simultaneous profiles of temperature (retrieved from a microwave radiometer) and water vapour mixing ratio (from a Raman lidar) is addressed. In the last part of this work, a statistical analysis of water vapour mixing ratio and relative humidity profiles obtained during 1 year of simultaneous measurements is presented.This work was supported by the Andalusian Regional Government through projects P12-RNM-2409 and P10-RNM-6299, by the Spanish Ministry of Science and Technology through projects CGL2010-18782, CSD2007-00067, CGL2011-13580-E/CLI and CGL2011-16124-E; and by the EU through the ACTRIS project (EU INFRA-2010-1.1.16-262254)

    Evaluation of LIRIC Algorithm Performance Using Independent Sun-Sky Photometer Data at Two Altitude Levels

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    The authors thank the FEDER program for the instrumentation used in this work and the University of Granada for supporting this study through the Excellence Units Program “Plan Propio. Programa23 Convocatoria 2017”. CIMEL Calibration was performed at the AERONET-EUROPE calibration center, supported by ACTRIS. We also express our gratitude to the developers of the LIRIC algorithm and software. The authors thank Sierra Nevada National Park for support in the maintenance of the Sun-sky photometer station at Cerro Poyos. Maria J. Granados-Muñoz is funded by a Maria Sklodowska-Curie IF under grant agreement no. 796539. Juan Antonio Bravo-Aranda and Antonio Valenzuela received funding from the Marie Sklodowska-Curie Action Cofund 2016 EU project Athenea3i under grant agreement no. 754446. Jose Antonio Benavent-Oltra is funded by the University of Granada through “Plan Propio. Programa 7, Convocatoria 2019”. This work was also supported by the Ambizione program of the Swiss National Science Foundation (project no. PZ00P2 168114).This work evaluates the Lidar-Radiometer Inversion Code (LIRIC) using sun-sky photometers located at different altitudes in the same atmospheric column. Measurements were acquired during an intensive observational period in summer 2012 at Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS)/Aerosol Robotic Network (AERONET) Granada (GRA; 37.16◩N, 3.61◩W, 680 m above sea level (a.s.l.)) and Cerro Poyos (CP; 37.11◩N, 3.49◩W, 1820 m a.s.l.) sites. Both stations operated AERONET sun-photometry, with an additional lidar system operating at Granada station. The extended database of simultaneous lidar and sun-photometry measurements from this study allowed the statistical analysis of vertically resolved microphysical properties retrieved with LIRIC, with 70% of the analyzed cases corresponding to mineral dust. Consequently, volume concentration values were 46 ”m3 /cm3 on average, with a value of ~30 ”m3 /cm3 corresponding to the coarse spheroid mode and concentrations below 10 ”m3 /cm3 for the fine and coarse spherical modes. According to the microphysical properties’ profiles, aerosol particles reached altitudes up to 6000 m a.s.l., as observed in previous studies over the same region. Results obtained from comparing the LIRIC retrievals from GRA and from CP revealed good agreement between both stations with differences within the expected uncertainties associated with LIRIC (15%). However, larger discrepancies were found for 10% of the cases, mostly due to the incomplete overlap of the lidar signal and/or to the influence of different aerosol layers advected from the local origin located between both stations, which is particularly important in cases of low aerosol loads. Nevertheless, the results presented here demonstrate the robustness and self-consistency of LIRIC and consequently its applicability to large databases such as those derived from ACTRIS-European Aerosol Research Lidar Network (EARLINET) observations.This work was supported by the Spanish Ministry of Economy and Competitiveness through projects CGL2016-81092-R, and CGL2017-83538-C3-1-R; the Excellence network CGL2017-90884-REDT; by the European Union’s Horizon 2020 research and innovation program through ACTRIS project (grant agreement n. 654169)

    Optical porperties of free tropospheric aerosol from multi-wavelength raman lidars over the southern Iberian Peninsula

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    Two cases of free tropospheric aerosol layers observed with multi-wavelength Raman lidars over Évora (Portugal) and Granada (Spain) were investigated. Optical properties, both, columnar and vertically-resolved, of a forest fire smoke plume from North America on 13 June 2011, and of mineral dust layers on 27 June 2011 are presented. The aerosol optical depth and Ångström exponents derived from lidar data were compared to sun photometer measurements. The aerosol optical depth at 355 nm of the free tropospheric smoke layers were about 25 to 30% of the columnar aerosol optical depth found from sun photometer measurements at both sites. The lidar ratio at 355 nm was 46±14 sr and 48±16 sr, over Évora and Granada, espectively. The lidar ratio at 532 nm over Évora was 66±19 sr. The investigation of the dust plume showed larger differences in the aerosol optical properties observed at the two sites. This was due to different transportation paths and intrusion of other aerosol types, namely anthropogenic and marine aerosols.The authors want to acknowledge the Portuguese Foundation for Sciences and Technology FCT for grant SFRH/BD/47521/2008 and projects REDE/1527/RNG/ 2007 and PTDC/CTE-ATM/65307/2006. This work was partially funded by the Spanish Ministry of Science and Technology through projects CGL2010-18782, CSD2007-00067 and CGL2011-13580-E/CLI as well as by the EU through the ACTRIS project (EUINFRA-2010-1.1.16-262254)

    Vertical characterization of fine and coarse dust particles during an intense Saharan dust outbreak over the Iberian Peninsula in springtime 2021

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    An intense and long-lasting Saharan dust outbreak crossed the Iberian Peninsula (IP) from the southwest (SW) to the northeast (NE) from 25 March until 7 April 2021. This work aims to assess the optical and mass contribution of both fine and coarse dust particles along their transport. Five Iberian lidar stations were monitoring the transport and evolution of the Saharan dust particles, i.e. El Arenosillo/Huelva, Granada, Torrejon/Madrid and Barcelona in Spain, and evora in Portugal. The particular meteorological conditions determined the aerosol scenario along the overall dust event, differing in the first part of the event (25-31 March), in which the strongest dust incidence occurred on 29-31 March at the south and central stations and 1 April at Barcelona, from the second one (1-7 April). The use of the two-step POLIPHON algorithm showed the relevance of using polarized lidar measurements for separating the aerosol properties of dust fine and coarse particles as an added value. Both the fine dust (Df) and coarse dust (Dc) components of the total particle backscatter coefficient (total dust, DD = Dc + Df) were separately derived. The dust plume was well-mixed with height and no significant differences were found in the vertical structure of both the Dc and Df particle backscatter coefficients. From the beginning of the dust outbreak until 1 April, the vertical Df / DD mass ratio was nearly constant in time at each station and also in altitude with values of & SIM; 10 %. Moreover, the mean dust optical depth at 532 nm was decreasing along that dust pathway, reporting values from SW to NE stations of 0.34 at El Arenosillo/Huelva, 0.28 at Granada, 0.20 at evora, 0.28 at Torrejon/Madrid, and 0.14 at Barcelona, although its Df / DD ratio remained almost constant (28 %-30 %). A similar pattern was found for the total dust mass loading and its Df / DD ratio, i.e. mostly decreasing mean mass values were reported, being constant in its Df / DD ratio (& SIM; 10 %) along the SW-NE dust pathway. In addition, the episode-mean centre-of-mass height increased with latitude overall, showing a high variability, being greater than 0.5 km at the southern sites (El Arenosillo/Huelva, Granada, evora) and & SIM; 1.0 km at Torrejon/Madrid and Barcelona. However, despite the relatively high intensity of the dust intrusion, the expected ageing of the dust particles was hardly observed, by taking into account the minor changes found in the contribution and properties of the coarse and fine dust particles. This is on the basis that the IP is relatively close to the Saharan dust sources and then, under certain dust transport conditions, any potential ageing processes in the dust particles remained unappreciated. The following must be highlighted: the different relative contribution of the fine dust particles to the total dust found for their optical properties (& SIM; 30 %) associated with the radiative effect of dust, with respect to that for the mass features (& SIM; 10 %) linked to air quality issues, along the overall dust event by crossing the IP.Ministry of Science and Innovation, Spain (MICINN) Spanish Government PID2019-104205GB-C21/AEI/10.13039/50110001103
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