541 research outputs found

    Functional strengthening through synaptic scaling upon connectivity disruption in neuronal cultures

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    An elusive phenomenon in network neuroscience is the extent of neuronal activity remodeling upon damage. Here, we investigate the action of gradual synaptic blockade on the effective connectivity in cortical networks in vitro. We use two neuronal cultures configurations—one formed by about 130 neuronal aggregates and another one formed by about 600 individual neurons—and monitor their spontaneous activity upon progressive weakening of excitatory connectivity. We report that the effective connectivity in all cultures exhibits a first phase of transient strengthening followed by a second phase of steady deterioration. We quantify these phases by measuring GEFF, the global efficiency in processing network information. We term hyperefficiency the sudden strengthening of GEFF upon network deterioration, which increases by 20–50% depending on culture type. Relying on numerical simulations we reveal the role of synaptic scaling, an activity–dependent mechanism for synaptic plasticity, in counteracting the perturbative action, neatly reproducing the observed hyperefficiency. Our results demonstrate the importance of synaptic scaling as resilience mechanism. Author Summary Neuronal circuits exhibit homeostatic plasticity mechanisms to cope with perturbations or damage. A central mechanism is ‘synaptic scaling,’ a self-organized response in which the strength of neurons’ excitatory synapses is adjusted to compensate for activity variations. Here we present experiments in which the excitatory connectivity of in vitro cortical networks is progressively weakened through chemical action. The spontaneous activity and effective connectivity of the whole network is monitored as degradation progresses, and the capacity of the network for broad information communication is quantified through the global efficiency. We observed that the network responded to the perturbation by strengthening the effective connectivity, reaching a hyperefficient state for moderate perturbations. The study proves the importance of ‘synaptic scaling’ as a driver for functional reorganization and network-wide resilience

    Smart Collaborative Mobile System for Taking Care of Disabled and Elderly People

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    Official statistics data show that in many countries the population is aging. In addition, there are several illnesses and disabilities that also affect a small sector of the population. In recent years, researchers and medical foundations are working in order to develop systems based on new technologies and enhance the quality of life of them. One of the cheapest ways is to take advantage of the features provided by the smartphones. Nowadays, the development of reduced size smartphones, but with high processing capacity, has increased dramatically. We can take profit of the sensors placed in smartphones in order to monitor disabled and elderly people. In this paper, we propose a smart collaborative system based on the sensors embedded in mobile devices, which permit us to monitor the status of a person based on what is happening in the environment, but comparing and taking decisions based on what is happening to its neighbors. The proposed protocol for the mobile ad hoc network and the smart system algorithm are described in detail. We provide some measurements showing the decisions taken for several common cases and we also show the performance of our proposal when there is a medium size group of disabled or elderly people. Our proposal can also be applied to take care of children in several situations.This work has been partially supported by the Instituto de Telecomunicacoes, Next Generation Networks and Applications Group (NetGNA), Portugal, and by National Funding from the FCT - Fundacao para a Ciencia e a Tecnologia through the PEst-OE/EEI/LA0008/2011 Project.Sendra Compte, S.; Granell Romero, E.; Lloret, J.; Rodrigues, JJPC. (2014). Smart Collaborative Mobile System for Taking Care of Disabled and Elderly People. Mobile Networks and Applications. 19(3):287-302. doi:10.1007/s11036-013-0445-zS287302193Cisco Systems Inc. “Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, 2010–2015.” White Paper, February 1, 2011Pereira O, Caldeira J, Rodrigues J (2011) Body sensor network mobile solutions for biofeedback monitoring. J Mob Netw Appl 16(6):713–732Google. Galaxy nexus (2012). Available: http://www.google.com/nexus/E. Commission. “Demography report 2010.” Eurostat, the Statistical Office of the European Union, 2010. At http://ec.europa.eu/social/BlobServlet?docId=6824&langId=enThomas KE, Stevens JA, Sarmiento K, Wald MM (2008) Fall-related traumatic brain injury deaths and hospitalizations among older adults—United States, 2005. J Saf Res 39(3):269–272Fortino G, Giannantonio R, Gravina R, Kuryloski P, Jafari R, (2013) Enabling effective programming and flexible management of efficient body sensor network applications. IEEE Trans Hum Mach Syst 43(1):115–133Bellifemine F, Fortino G, Giannantonio R, Gravina R, Guerrieri A, Sgroi M (2011) SPINE: a domain-specific framework for rapid prototyping of WBSN applications. Softw Pract Exper 41(3):237–265Macias E, Lloret J, Suarez A, Garcia M (2012) Architecture and protocol of a semantic system designed for video tagging with sensor data in mobile devices. Sensors 12(2):2062–2087Sendra S, Granell E, Lloret J, Rodrigues JJPC. Smart Collaborative System Using the Sensors of Mobile Devices for Monitoring Disabled and Elderly People, 3rd IEEE International Workshop on Smart Communications in Network Technologies, Ottawa, Canada, June 11, 2012Lane N, Miluzzo E, Lu H, Peebles D, Choudhury T, Campbell A (2010) A survey of mobile phone sensing. IEEE Commun Mag 48(9):140–150Muldoon C, OHare G, OGrady M (2006) Collaborative agent tuning: Performance enhancement on mobile devices Engineering Societies in the Agents World VI, Lecture Notes in Computer Science, Volume 3963/2006, pp 241–258Turner H, White J, Thompson C, Zienkiewicz K, Campbell S, Schmidt DC (2009) Building Mobile Sensor Networks Using Smartphones and Web Services: Ramifications and Development Challenges, Handbook of Research on Mobility and Computing, Hershey, PA. Available: http://lsrg.cs.wustl.edu/~schmidt/PDF/new-ww-mobile-computing.pdfKansal A, Goraczko M, Zhao F. Building a sensor network of mobile phones, 6th International Conference on Information Processing in Sensor Networks. Cambridge, Massachusetts, USA, April 24–27, 2007 pp 547–548Plaza I, Martín L, Martin S, Medrano C (2011) Mobile applications in an aging society: status and trends. J Syst Softw 84(11):1977–1988Camarinha-Matos L, Afsarmanesh H. Telecare: Collaborative virtual elderly support communities, 1st Workshop on Tele-Care and Collaborative Virtual Communities in Elderly Care, Porto, Portugal, 13 April, 2004Chen B, Pompili D (2011) Transmission of patient vital signs using wireless body area networks. J Mob Netw Appl 16(6):663–682Dai J, Bai X, Yang Z, Shen Z, Xuan D (2010) Mobile phone-based pervasive fall detection. Pers Ubiquit Comput 14(7):633–643Martin P, Sánchez MA, Álvarez L, Alonso V, Bajo J. Multiagent system for detecting elderly people falls through mobile devices, International Symposium on Ambient Intelligence (ISAmI’11), Salamanca (Spain) 6–8 April 2011Fahmi PN, Viet V, Deok-Jai C. “Semi-supervised fall detection algorithm using fall indicators in smartphone.” Proceedings of the 6th International Conference on Ubiquitous Information Management and Communication, 2012, pp 122Sánchez M, Martín P, Álvarez L, Alonso V, Zato C, Pedrero A, Bajo J (2011) A New Adaptive Algorithm for Detecting Falls through Mobile Devices, Trends in Practical Applications of Agents and Multiagent Systems, pp 17–24Fahim M, Fatima I, Lee S, Lee YK. Daily Life Activity Tracking Application for Smart Homes using Android Smartphone, 14th International Conference on Advanced Communication Technology, Yongin, South Korea, 19–22 February 2012, pp 241–245Kaluža B, Mirchevska V, Dovgan E, Luštrek M, Gams M (2010) An agent-based approach to care in independent living, Ambient Intelligence, Lecture Notes in Computer Science, vol. 6439, pp 177–186Costa A, Barbosa G, Melo T, Novais P (2011) Using mobile systems to monitor an ambulatory patient. In: International Symposium on Distributed Computing and Artificial Intelligence, Advances in Intelligent and Soft Computing, vol. 91, pp 337–344Olfati-Saber R, Fax J, Murray R (2007) Consensus and cooperation in networked multi-agent systems. Proc IEEE 95(1):215–233Arcelus A, Jones MH, Goubran R, Knoefel F (2007) Integration of smart home technologies in a health monitoring system for the elderly, 21st International Conference on Advanced Information Networking and Applications Workshops, vol. 2, pp 820–825Kahmen H, Faig W (1988) Surveying. Walter de Gruyter & Co, New YorkSol LM870 mobile phone features. Available at: http://es.made-in-china.com/co_runrise/product_Dual-SIM-Card-Dual-Standby-GPS-Temperature-UV-Sensor-Pedometer-Sunrise-LM870-Mobile-Phone_hesighyiy.htmlSTLM20 temperature sensor features. Datashhet available at: http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00119601.pdfSendra S, Lloret J, Garcia M, Toledo JF (2011) Power saving and energy optimization techniques for wireless sensor networks. J Commun 6(6):439–459Matlab Website. Available at: www.mathworks.com/products/matlabPal A (2010) Localization algorithms in wireless sensor networks: current approaches and future challenges. Netw Protocol Algorithm 2(1):45–74Garcia M, Boronat F, Tomás J, Lloret J (2009) The development of two systems for indoor wireless sensors self-location. Ad Hoc Sensor Wirel Netw 8(3–4):235–258Lloret J, Tomás J, Garcia M, Cánovas A (2009) A hybrid stochastic approach for self-location of wireless sensors in indoor environments. Sensors 9(5):3695–3712Garcia M, Sendra S, Turro C, Lloret J (2011) User’s macro and micro-mobility study using WLANs in a university campus. Int J Adv Internet Technol 4(1&2):37–46Lloret J, Tomas J, Canovas A, Bellver I. GeoWiFi: A Geopositioning System Based on WiFi Networks, The Seventh International Conference on Networking and Services (ICNS 2011), Venice (Italy), May 6–10, 2011Yu W, Su X, Hansen J (2012) A smartphone design approach to user communication interface for administering storage system network. Netw Protoc Algorithm 4(4):126–15

    Geospatial information infrastructures

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    Manual of Digital Earth / Editors: Huadong Guo, Michael F. Goodchild, Alessandro Annoni .- Springer, 2020 .- ISBN: 978-981-32-9915-3Geospatial information infrastructures (GIIs) provide the technological, semantic,organizationalandlegalstructurethatallowforthediscovery,sharing,and use of geospatial information (GI). In this chapter, we introduce the overall concept and surrounding notions such as geographic information systems (GIS) and spatial datainfrastructures(SDI).WeoutlinethehistoryofGIIsintermsoftheorganizational andtechnologicaldevelopmentsaswellasthecurrentstate-of-art,andreflectonsome of the central challenges and possible future trajectories. We focus on the tension betweenincreasedneedsforstandardizationandtheever-acceleratingtechnological changes. We conclude that GIIs evolved as a strong underpinning contribution to implementation of the Digital Earth vision. In the future, these infrastructures are challengedtobecomeflexibleandrobustenoughtoabsorbandembracetechnological transformationsandtheaccompanyingsocietalandorganizationalimplications.With this contribution, we present the reader a comprehensive overview of the field and a solid basis for reflections about future developments

    GEO-C:Enabling open cities and the open city toolkit

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    The GEO-C doctoral programme, entitled “Geoinformatics: Enabling Open Cities”, is funded by the EU Marie Skłodowska-Curie actions (International Training Networks (ITN), European Joint Doctorates) until December 2018, and is managed by three European universities in Germany, Portugal and Spain. 15 doctoral grantholders (Early Stage Researchers) were selected to work on specific three-year projects, all contributing to improving the notion of open cities, and specifically to an Open City Toolkit of methodologies, code, and best practice examples. Contributions include volunteered geographic information (VGI), public information displays, mobility apps to encourage green living, providing open data to immigrant populations, reducing the second-order digital divide, sensing of quality of life, proximity based privacy protection, and spatio-temporal online social media analysis. All doctoral students conducted long-term visits and were embedded in city governments and businesses, to gain experience from multiple perspectives in addition to the researcher and users’ perspective. The projects are situated within three areas: transparency, participation, and collaboration. They took mostly a bottom-up (citizen-centric) approach to (smart) open cities, rather than relying on large IT companies to create smart open cities in a top-down manner. This paper discusses the various contributions to enabling open cities, explains in some detail the Open City Toolkit, and its possible uses and impact on stakeholders. A follow-up doctoral program has been solicited and, if successful, will continue this line of research and will strengthen aspects of privacy, data provenance, and trust, in an effort to improve relations between data (e.g. news) publishers and consumers

    Integrating Concepts of Artificial Intelligence in the EO4GEO Body of Knowledge

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    Ponència del XXIV ISPRS Congress (2022 edition), 6–11 June 2022, Nice, FranceThe EO4GEO Body of Knowledge (BoK) forms a structure of concepts and relationships between them, describing the domain of Earth Observation and Geo-Information (EO/GI). Each concept carries a short description, a list of key literature references and a set of associated skills which are used for job profiling and curriculum building. As the EO/GI domain is evolving continuously, the BoK needs regular updates with new concepts embodying new trends, and deprecating concepts which are not relevant anymore. This paper presents the inclusion of BoK concepts related to Artificial Intelligence. This broad field of knowledge has links to several applications in EO/GI. Its connection to concepts, already existing in the BoK, needs special attention. To perform a clean and structural integration of the cross-cutting domain of AI, first a separate cluster of AI concepts was created, which was then merged with the existing BoK. The paper provides examples of this integration with specific concepts and examples of training resources in which AI-related concepts are used. Although the presented structure already provides a good starting point, the positioning of AI within the EO/GI-focussed BoK needs to be further enhanced with the help of expert calls as part of the BoK update cycle

    Modeling the Spatiotemporal Epidemic Spreading of COVID-19 and the Impact of Mobility and Social Distancing Interventions

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    On 31 December, 2019, an outbreak of a novel coronavirus, SARS-CoV-2, that causes the COVID-19 disease, was first reported in Hubei, mainland China. This epidemics'' health threat is probably one of the biggest challenges faced by our interconnected modern societies. According to the epidemiological reports, the large basic reproduction number R0~3.0, together with a huge fraction of asymptomatic infections, paved the way for a major crisis of the national health capacity systems. Here, we develop an age-stratified mobility-based metapopulation model that encapsulates the main particularities of the spreading of COVID-19 regarding (i) its transmission among individuals, (ii) the specificities of certain demographic groups with respect to the impact of COVID-19, and (iii) the human mobility patterns inside and among regions. The full dynamics of the epidemic is formalized in terms of a microscopic Markov chain approach that incorporates the former elements and the possibility of implementing containment measures based on social distancing and confinement. With this model, we study the evolution of the effective reproduction number R(t), the key epidemiological parameter to track the evolution of the transmissibility and the effects of containment measures, as it quantifies the number of secondary infections generated by an infected individual. The suppression of the epidemic is directly related to this value and is attained when R<1. We find an analytical expression connecting R with nonpharmacological interventions, and its phase diagram is presented. We apply this model at the municipality level in Spain, successfully forecasting the observed incidence and the number of fatalities in the country at each of its regions. The expression for R should assist policymakers to evaluate the epidemics'' response to actions, such as enforcing or relaxing confinement and social distancing

    Early childhood wheezing phenotypes and determinants in a South African birth cohort: longitudinal analysis of the Drakenstein Child Health Study

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    BACKGROUND: Developmental trajectories of childhood wheezing in low-income and middle-income countries (LMICs) have not been well described. We aimed to derive longitudinal wheeze phenotypes from birth to 5 years in a South African birth cohort and compare those with phenotypes derived from a UK cohort. METHODS: We used data from the Drakenstein Child Health Study (DCHS), a longitudinal birth cohort study in a peri-urban area outside Cape Town, South Africa. Pregnant women (aged ≥18 years) were enrolled during their second trimester at two public health clinics. We followed up children from birth to 5 years to derive six multidimensional indicators of wheezing (including duration, temporal sequencing, persistence, and recurrence) and applied Partition Around Medoids clustering to derive wheeze phenotypes. We compared phenotypes with a UK cohort (the Avon Longitudinal Study of Parents and Children [ALSPAC]). We investigated associations of phenotypes with early-life exposures, including all-cause lower respiratory tract infection (LRTI) and virus-specific LRTI (respiratory syncytial virus, rhinovirus, adenovirus, influenza, and parainfluenza virus) up to age 5 years. We investigated the association of phenotypes with lung function at 6 weeks and 5 years. FINDINGS: Between March 5, 2012, and March 31, 2015, we enrolled 1137 mothers and there were 1143 livebirths. Four wheeze phenotypes were identified among 950 children with complete data: never (480 children [50%]), early transient (215 children [23%]), late onset (104 children [11%]), and recurrent (151 children [16%]). Multivariate adjusted analysis indicated that LRTI and respiratory syncytial virus-LRTI, but not other respiratory viruses, were associated with increased risk of recurrent wheeze (odds ratio [OR] 2·79 [95% CI 2·05-3·81] for all LTRIs; OR 2·59 [1·30-5·15] for respiratory syncytial virus-LRTIs). Maternal smoking (1·88 [1·12-3·02]), higher socioeconomic status (2·46 [1·23-4·91]), intimate partner violence (2·01 [1·23-3·29]), and male sex (2·47 [1·50-4·04]) were also associated with recurrent wheeze. LRTI and respiratory syncytial virus-LRTI were also associated with early transient and late onset clusters. Wheezing illness architecture differed between DCHS and ALSPAC; children included in ALSPAC in the early transient cluster wheezed for a longer period before remission and late-onset wheezing started at an older age, and no persistent phenotype was identified in DCHS. At 5 years, airway resistance was higher in children with early or recurrent wheeze compared with children who had never wheezed. Airway resistance increased from 6 weeks to 5 years among children with recurrent wheeze. INTERPRETATION: Effective strategies to reduce maternal smoking and psychosocial stressors and new preventive interventions for respiratory syncytial virus are urgently needed to optimise child health in LMICs. FUNDING: UK Medical Research Council; The Bill & Melinda Gates Foundation; National Institutes of Health Human Heredity and Health in Africa; South African Medical Research Council; Wellcome Trust
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