103 research outputs found
Cognitive reserve index and functional and cognitive outcomes in severe acquired brain injury: A pilot study
Background: Many variables affect outcome after brain injury. Cognitive reserve (CR) is a subjective factor that reflects a set of personal characteristics and that differentiates individuals. It may influence an individual’s capacity to react to brain injury. Objective: To study the effects of cognitive reserve on functional and cognitive outcome at the end of rehabilitation, in patients with severe acquired brain injury (sABI), by means of the Cognitive Reserve Index questionnaire (CRIq). Methods: We report a retrospective study of a continuous series of sABI patients on first admission to a rehabilitation center. Disability and cognitive outcomes were recorded. Results: In the 94 patients enrolled, the assessments after rehabilitation showed a significant gain measured with the disability Rating Scale for patients with a higher CR (CRIq≥ 85). A significant negative correlation was found: between CRIq scores and the interval elapsing before first access to neuropsychological assessment, between CRIq scores, especially level of education, and tests that measure the same domain (attention). Conclusions: Improvements in overall and cognitive disability emerged, but CR did not seem to substantially influence outcome in this sample of patients. This result may be partly due to the clinical severity of the population studied and the sample’s dimension, although quantitatively representative of the population
RF Energy Harvester-based Wake-up Receiver
Wake-up receivers (WuRxs) can improve the life-
time of a wireless sensor network by reducing energy consump-
tion from undesirable idle listening. The amplitude level of the
incoming RF signal is used by a WuRx to generate an interrupt
and wake up the radio of a sleeping sensor node. Existing passive
WuRx designs are generally based on RFID tags that incur high
cost and complexity. Thus, there is a need for cost-effective and
low-complexity WuRxs suited for both long-range and directed
wake-ups. In this work, we present a WuRx design using an RF
energy harvesting circuit (RFHC). Experimental results show that
our RFHC-based WuRx can provide a wake-up range sensitivity
around
4
cm/mW at low transmit RF powers (
<
20
mW),
which scales to a long wake-up range at high powers. Our
design also obtains accurate selective wake-ups. We finally present
simulation-based studies for optimizing the design of RFHCs that
enhance decoding efficiency with improved rise and fall times
A heuristic algorithm for finding attractive fixed-length circuits in street maps
In this paper we consider the problem of determining fixed-length routes on a street map that start and end at the same location. We propose a heuristic for this problem based on finding pairs of edge-disjoint shortest paths, which can then be combined into a circuit. Various heuristics and filtering techniques are also proposed for improving the algorithm’s performance
Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds
The presence of positron emission tomography (PET) centers at most major hospitals worldwide, along with the improvement of PET scanner sensitivity and the
introduction of total body PET systems, has increased the interest in the PET tracer development using the short-lived radionuclides carbon-11. In the last few decades,
methodological improvements and fully automated modules have allowed the development of carbon-11 tracers for clinical use. Radiolabeling natural compounds with carbon-11 by substituting one of the backbone carbons with the radionuclide has provided important information on the biochemistry of the authentic compounds and increased the understanding of their in vivo behavior in healthy and diseased states. The number of endogenous and natural compounds essential for human life is staggering, ranging from simple alcohols to vitamins and peptides. This review collates all the carbon-11 radiolabeled endogenous and natural exogenous compounds synthesised to date, including essential information on their radiochemistry methodologies and preclinical and clinical studies in healthy subjects
Using location services to autonomously drive flying mobile sinks in Wireless Sensor Networks
International audienceThe use of mobility in a Wireless Sensor Network has already been indicated as a feature whose exploitation would increase the performances and the ease of mantainance in these environments. Expecially in a event-based WSN, where is necessary a prompt response in terms of data processing and o oading, a set of mobile ying sinks could be a good option for the role of autonomous data collectors. For those reasons in this paper we propose a distributed algorithm to independently and autonomously drive a mobile sink through the nodes of a WSN and we show its preferability over more classical routing approaches expecially in the presence of a localized generation of large amount of information. Our result shows that, in the case of fairly complete coverage of the area where the nodes lie, it is possible to promptly notify a mobile sink about the presence of data to o oad, drive it to the interested area and achieve interesting performances
Listing Maximal Independent Sets with Minimal Space and Bounded Delay
International audienceAn independent set is a set of nodes in a graph such that no two of them are adjacent. It is maximal if there is no node outside the independent set that may join it. Listing maximal independent sets in graphs can be applied, for example, to sample nodes belonging to different communities or clusters in network analysis and document clustering. The problem has a rich history as it is related to maximal cliques, dominance sets, vertex covers and 3-colorings in graphs. We are interested in reducing the delay, which is the worst-case time between any two consecutively output solutions, and the memory footprint, which is the additional working space behind the read-only input graph
A fast and accurate energy source emulator for wireless sensor networks
The capability to either minimize energy consumption in battery-operated devices, or to adequately exploit energy harvesting from various ambient sources, is central to the development and engineering of energy-neutral wireless sensor networks. However, the design of effective networked embedded systems targeting unlimited lifetime poses several challenges at different architectural levels. In particular, the heterogeneity, the variability, and the unpredictability of many energy sources, combined to changes in energy required by powered devices, make it difficult to obtain reproducible testing conditions, thus prompting the need of novel solutions addressing these issues. This paper introduces a novel embedded hardware-software solution aimed at emulating a wide spectrum of energy sources usually exploited to power sensor networks motes. The proposed system consists of a modular architecture featuring small factor form, low power requirements, and limited cost. An extensive experimental characterization confirms the validity of the embedded emulator in terms of flexibility, accuracy, and latency while a case study about the emulation of a lithium battery shows that the hardware-software platform does not introduce any measurable reduction of the accuracy of the model. The presented solution represents therefore a convenient solution for testing large-scale testbeds under realistic energy supply scenarios for wireless sensor networks
Distance-Based and Low Energy Adaptive Clustering Protocol for Wireless Sensor Networks
A wireless sensor network (WSN) comprises small sensor nodes with limited energy capabilities. The power constraints of WSNs necessitate efficient energy utilization to extend the overall network lifetime of these networks. We propose a distance-based and low-energy adaptive clustering (DISCPLN) protocol to streamline the green issue of efficient energy utilization in WSNs. We also enhance our proposed protocol into the multi-hop-DISCPLN protocol to increase the lifetime of the network in terms of high throughput with minimum delay time and packet loss. We also propose the mobile-DISCPLN protocol to maintain the stability of the network. The modelling and comparison of these protocols with their corresponding benchmarks exhibit promising results
Internet of Things for Sustainable Community Development: Introduction and Overview
The two-third of the city-dwelling world population by 2050 poses numerous global challenges in the infrastructure and natural resource management domains (e.g., water and food scarcity, increasing global temperatures, and energy issues). The IoT with integrated sensing and communication capabilities has the strong potential for the robust, sustainable, and informed resource management in the urban and rural communities. In this chapter, the vital concepts of sustainable community development are discussed. The IoT and sustainability interactions are explained with emphasis on Sustainable Development Goals (SDGs) and communication technologies. Moreover, IoT opportunities and challenges are discussed in the context of sustainable community development
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