Patch Antenna Based on Metamaterials for a RFID Transponder

In this paper a self-diplexed antenna is proposed for a RFID transponder application. The development cycle is divided into two stages: antenna design and filters design. The antenna is based on a square microstrip patch filled with metamaterial structures. The inclusion of these structures allows simultaneous operation over several frequencies, which can be arbitrarily chosen. The antenna working frequencies are chosen to be 2.45 GHz (receiver) and 1.45 GHz (transmitter). In addition, the antenna is fed through two orthogonal coupled microstrip lines, what provides higher isolation between both ports. Some filters based on metamaterial particles are coupled or connected to the antenna feeding microstrip lines to avoid undesired interferences. This approach avoids using of an external filter or diplexer, providing larger size reduction and a compact self-diplexed antenna

The Respiratory Exchange Ratio is Associated with Fitness Indicators Both in Trained and Untrained Men: A Possible Application for People with Reduced Exercise Tolerance

Background The respiratory exchange ratio (RER) indirectly shows the muscle's oxidative capacity to get energy. Sedentarism, exercise and physically active lifestyles modify it. For that reason, this study evaluates the associations between RER during sub-maximum exercise and other well established fitness indicators (body fat, maximum heart rate, maximum O 2 uptake, workload, and lactate threshold), in physically active trained and untrained men. Methods The RER, O 2 uptake and blood lactate were measured in eight endurance trained and eight untrained men (age, 22.9 ± 4.5 vs. 21.9 ± 2.8 years; body mass, 67.1 ± 5.4 vs. 72.2 ± 7.7 kg; body fat, 10.6 ± 2.4% vs. 16.6 ± 3.8% and maximum O2 uptake, 68.9 ± 6.3 vs. 51.6 ± 5.8 ml · kg −1 · min −1 ), during maximum exercise test and during three different sub-maximum exercises at fixed workload: below, within or above the lactate threshold. Results Endurance trained men presented higher O 2 uptake, lower blood lactate concentrations and lower RER values than those in untrained men at the three similar relative workloads. Even though with these differences in RER, a strong association (p < 0.05) of RER during sub-maximum exercise with the other well established fitness indicators was observed, and both maximum O 2 uptake and lactate threshold determined more than 57% of its variance (p < 0.05). Conclusions These data demonstrate that RER measurement under sub-maximum exercise conditions was well correlated with other established physical fitness indicators, despite training condition. Furthermore, the results suggest that RER could help obtain an easy approach of fitness status under low exercise intensity and could be utilized in subjects with reduced exercise tolerance

Stability Analysis and Design of Negative Impedance Converters: Application to Circuit and Small Antennas

Negative impedance converters (NICs) have been proposed as structures to improve the performance of RF circuits and electrically small antennas. However, NICs suffer from stability problems. This paper presents a compact procedure to analyze the stability of NICs. Then, the required and sufficient conditions to predict the stability of a negative impedance converter are given. These conditions can be evaluated using standard computer-aided-design software. Finally, a NIC prototype is given to validate and illustrate the presented design procedure, it is also integrated with a printed, blade-type, electrically small monopole in the VHF ban

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Extending MAM5 Meta-Model and JaCalIVE Framework to Integrate Smart Devices from Real Environments

[EN] This paper presents the extension of a meta-model (MAM5) and a framework based on the model (JaCalIVE) for developing intelligent virtual environments. The goal of this extension is to develop augmented mirror worlds that represent a real and virtual world coupled, so that the virtual world not only reflects the real one, but also complements it. A new component called a smart resource artifact, that enables modelling and developing devices to access the real physical world, and a human in the loop agent to place a human in the system have been included in the meta-model and framework. The proposed extension of MAM5 has been tested by simulating a light control system where agents can access both virtual and real sensor/actuators through the smart resources developed. The results show that the use of real environment interactive elements (smart resource artifacts) in agent-based simulations allows to minimize the error between simulated and real system.This work is partially supported by the TIN2009-13839-C03-01, TIN2011-27652-C03-01, 547CSD2007-00022, COST Action IC0801, FP7-294931 and the FPI grant AP2013-01276 548 awarded to Jaime-Andres Rincon.Rincón Arango, JA.; Poza Luján, JL.; Julian Inglada, VJ.; Posadas Yagüe, JL.; Carrascosa Casamayor, C. (2016). Extending MAM5 Meta-Model and JaCalIVE Framework to Integrate Smart Devices from Real Environments. PLoS ONE. 11(2):1-27. https://doi.org/10.1371/journal.pone.0149665S127112Luck, M., & Aylett, R. (2000). Applying artificial intelligence to virtual reality: Intelligent virtual environments. Applied Artificial Intelligence, 14(1), 3-32. doi:10.1080/088395100117142Barella A, Ricci A, Boissier O, Carrascosa C. MAM5: Multi-Agent Model For Intelligent Virtual Environments. In: 10th European Workshop on Multi-Agent Systems (EUMAS 2012); 2012. p. 16–30.Omicini, A., Ricci, A., & Viroli, M. (2008). Artifacts in the A&A meta-model for multi-agent systems. Autonomous Agents and Multi-Agent Systems, 17(3), 432-456. doi:10.1007/s10458-008-9053-xYu Ch, Nagpal R. Distributed Consensus and Self-Adapting Modular Robots. In: IROS-2008 workshop on Self-Reconfigurable Robots and Applications; 2008. Available from: http://www.isi.edu/robots/iros08wksp/Papers/iros08-wksp-paper.pdfLidoris G, Buss M. A Multi-Agent System Architecture for Modular Robotic Mobility Aids. In: European Robotics Symposium 2006; 2006. p. 15–26. Available from: http://link.springer.com/chapter/10.1007/11681120_2Yu, C.-H., & Nagpal, R. (2010). A Self-adaptive Framework for Modular Robots in a Dynamic Environment: Theory and Applications. The International Journal of Robotics Research, 30(8), 1015-1036. doi:10.1177/0278364910384753Barbero A, González-Rodríguez MS, de Lara J, Alfonseca M. Multi-Agent Simulation of an Educational Collaborative Web System. In: European Simulation and Modelling Conference; 2007. Available from: http://sistemas-humano-computacionais.wikidot.com/local--files/capitulo:colaboracao-auxiliada-por-computador/%5BBarbero%202007%5D%20Multi-Agent%20Simulation%20of%20an%20Educational%20Collaborative%20Web%20System.pdfRanathunga S, Cranefield S, Purvis MK. Interfacing a cognitive agent platform with a virtual world: a case study using Second Life. In: AAMAS; 2011. p. 1181–1182. Available from: http://www.aamas-conference.org/Proceedings/aamas2011/papers/B20.pdfAndreoli R, De Chiara R, Erra U, Scarano V. Interactive 3d environments by using videogame engines. In: Information Visualisation, 2005. Proceedings. Ninth International Conference on. IEEE; 2005. p. 515–520. Available from: http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1509124Dignum, F. (2011). Agents for games and simulations. Autonomous Agents and Multi-Agent Systems, 24(2), 217-220. doi:10.1007/s10458-011-9169-2dos Santos C, Osorio F. AdapTIVE: an intelligent virtual environment and its application in e-commerce. In: Computer Software and Applications Conference, 2004. COMPSAC 2004. Proceedings of the 28th Annual International; 2004. p. 468–473 vol.1.Kazemi, A., Fazel Zarandi, M. H., & Moattar Husseini, S. M. (2008). A multi-agent system to solve the production–distribution planning problem for a supply chain: a genetic algorithm approach. The International Journal of Advanced Manufacturing Technology, 44(1-2), 180-193. doi:10.1007/s00170-008-1826-5Dimuro GP, Costa ACdR, Gonçalves LV, Hubner A. Interval-valued Hidden Markov Models for recognizing personality traits in social exchanges in open multiagent systems. Repositório Institucional da Universidade Federal do Rio Grande. 2008;.Woźniak, M., Graña, M., & Corchado, E. (2014). A survey of multiple classifier systems as hybrid systems. Information Fusion, 16, 3-17. doi:10.1016/j.inffus.2013.04.006Jia L, Zhenjiang M. Entertainment Oriented Intelligent Virtual Environment with Agent and Neural Networks. In: IEEE International Workshop on Haptic, Audio and Visual Environments and Games, 2007. HAVE 2007; 2007. p. 90–95.Corchado, E., Woźniak, M., Abraham, A., de Carvalho, A. C. P. L. F., & Snášel, V. (2014). Recent trends in intelligent data analysis. Neurocomputing, 126, 1-2. doi:10.1016/j.neucom.2013.07.001Ricci A, Viroli M, Omicini A. Give agents their artifacts: the A&amp;A approach for engineering working environments in MAS. In: Proceedings of the 6th international joint conference on Autonomous agents and multiagent systems; 2007. p. 150. Available from: http://dl.acm.org/citation.cfm?id=1329308Barella, A., Valero, S., & Carrascosa, C. (2009). JGOMAS: New Approach to AI Teaching. IEEE Transactions on Education, 52(2), 228-235. doi:10.1109/te.2008.925764Behrens, T. M., Hindriks, K. V., & Dix, J. (2010). Towards an environment interface standard for agent platforms. Annals of Mathematics and Artificial Intelligence, 61(4), 261-295. doi:10.1007/s10472-010-9215-9Ricci A, Viroli M, Omicini A. A general purpose programming model &amp; technology for developing working environments in MAS. In: 5th International Workshop Programming Multi-Agent Systems(PROMAS 2007); 2007. p. 54–69. Available from: http://lia.deis.unibo.it/~ao/pubs/pdf/2007/promas.pdfChee-Yee Chong, & Kumar, S. P. (2003). Sensor networks: Evolution, opportunities, and challenges. Proceedings of the IEEE, 91(8), 1247-1256. doi:10.1109/jproc.2003.814918Kushner D. The making of arduino. IEEE Spectrum. 2011;26.Schmidt, A., & van Laerhoven, K. (2001). How to build smart appliances? IEEE Personal Communications, 8(4), 66-71. doi:10.1109/98.944006Salzmann C, Gillet D. Smart device paradigm standardization for online labs. In: 4th IEEE Global Engineering Education Conference (EDUCON); 2013.Gonzalez-Jorge, H., Riveiro, B., Vazquez-Fernandez, E., Martínez-Sánchez, J., & Arias, P. (2013). Metrological evaluation of Microsoft Kinect and Asus Xtion sensors. Measurement, 46(6), 1800-1806. doi:10.1016/j.measurement.2013.01.011Cook, D. J., & Das, S. K. (2007). How smart are our environments? An updated look at the state of the art. Pervasive and Mobile Computing, 3(2), 53-73. doi:10.1016/j.pmcj.2006.12.001Compton, M., Barnaghi, P., Bermudez, L., García-Castro, R., Corcho, O., Cox, S., … Taylor, K. (2012). The SSN ontology of the W3C semantic sensor network incubator group. Journal of Web Semantics, 17, 25-32. doi:10.1016/j.websem.2012.05.003Munera, E., Poza-Lujan, J.-L., Posadas-Yagüe, J.-L., Simó-Ten, J.-E., & Noguera, J. (2015). Dynamic Reconfiguration of a RGBD Sensor Based on QoS and QoC Requirements in Distributed Systems. Sensors, 15(8), 18080-18101. doi:10.3390/s150818080Castrillón-Santan, M., Lorenzo-Navarro, J., & Hernández-Sosa, D. (2014). Conteo de personas con un sensor RGBD comercial. Revista Iberoamericana de Automática e Informática Industrial RIAI, 11(3), 348-357. doi:10.1016/j.riai.2014.05.006Rincon JA, Julian V, Carrascosa C. An Emotional-based Hybrid Application for Human-Agent Societies. In: 10th International Conference on Soft Computing Models in Industrial and Environmental Applications. vol. 368; 2015. p. 203–214.Rincon JA, Julian V, Carrascosa C. Applying a Social Emotional Model in Human-Agent Societies. In: Workshop WIHAS’15. Intelligent Human-Agent Societies‥ vol. 524 of CCIS; 2015. p. 377–388.Leccese, F., Cagnetti, M., & Trinca, D. (2014). A Smart City Application: A Fully Controlled Street Lighting Isle Based on Raspberry-Pi Card, a ZigBee Sensor Network and WiMAX. Sensors, 14(12), 24408-24424. doi:10.3390/s141224408Mateevitsi V, Haggadone B, Leigh J, Kunzer B, Kenyon RV. Sensing the environment through SpiderSense. In: Proceedings of the 4th Augmented Human International Conference. ACM; 2013. p. 51–57.Kavitha R, Thiyagarajan N. Distributed Intelligent Street Lamp Monitoring and Control System Based on Zigbee. International Journal of Science and Research (IJSR) PP; p. 2319–7064.Pan, M.-S., Yeh, L.-W., Chen, Y.-A., Lin, Y.-H., & Tseng, Y.-C. (2008). A WSN-Based Intelligent Light Control System Considering User Activities and Profiles. IEEE Sensors Journal, 8(10), 1710-1721. doi:10.1109/jsen.2008.2004294Villarrubia, G., De Paz, J., Bajo, J., & Corchado, J. (2014). Ambient Agents: Embedded Agents for Remote Control and Monitoring Using the PANGEA Platform. Sensors, 14(8), 13955-13979. doi:10.3390/s14081395

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Dual Band High Efficiency Power Amplifier Based on CRLH Lines

In this paper we propose the use of Composite Right/Left Hand (CRLH) and Extended Composite Right/Left Hand (ECRLH) transmission lines for the design of dual band high efficiency power amplifiers working in CE class. The harmonic termination can be synthesized using the meta-lines is particularly suitable for CE class amplifiers, which have a termination not as sensitive to the third harmonic as F class amplifier. This paper presents the design procedure and the design equations. The nonlinear phase response of a CRLH and ECRLH transmission line has been utilized to design arbitrary dual-band amplifiers

Multifrequency Printed Antennas Loaded with Metamaterial Particles

This paper provides a review of printed antennas loaded with metamaterial particles. This novel technique allows developing printed antennas with interesting features such as multifrequency (simultaneous operation over two or more frequency bands) and multifunctionality (e. g. radiation pattern diversity). Moreover, compactness is also achieved and the main advantages of conventional printed antennas (light weight, low profile, low cost ...) are maintained. Different types of metamaterial-loaded printed antennas are reviewed: printed dipoles and patch antennas. Several prototypes are designed, manufactured and measured showing good results. Furthermore, simple but accurate equivalent models are proposed. These models allow an easy and quick design of metamaterial-loaded printed antennas. Finally, two interesting applications based on the proposed antennas are reviewed: the patch antennas are used as radiating elements of emerging active RFID systems in the microwave band and the metamaterial-loaded printed dipoles are employed to increase the performance of log-periodic arrays