744 research outputs found
The assessment of hemineglect syndrome with cancellation tasks. A comparison between the bells test and the Apples test
Unilateral spatial neglect (USN) is a frequent consequence of acquired brain injury, especially following right hemisphere damage. Traditionally, unilateral spatial neglect is assessed with cancellation tests such as the Bells test. Recently, a new cancellation test, the Apples test, has been proposed. The present study aims at comparing the accuracy of these two tests in detecting hemispatial neglect, on a sample of 56 right hemisphere stroke patients with a diagnosis of USN. In order to evaluate the agreement between the Apples and Bells tests, Cohen's kappa and McNemar's test were used to assess differences between the two methods of evaluation. Poor agreement and statistically significant differences emerged between the Apples and Bells tests. Overall, the Apples test was significantly more sensitive than the Bells test in detecting USN. Based on these results, the use of the Apples test for peripersonal neglect assessment is therefore highly recommende
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
Range Extension of Passive Wake-up Radio Systems through Energy Harvesting
Abstract—Use of a passive wake-up radio can drastically increase the network lifetime in a sensor network by reducing or even completely eliminating unnecessary idle listening. A sensor node with a wake-up radio receiver (WuRx) can operate in an extremely low power sleep mode until it receives a trigger signal sent by a wake-up radio transmitter (WuTx). After receiving the trigger signal, the attached WuRx wakes up the sensor node to start the data communication. In this paper, we implement and compare the performance of three passive wake-up radio-based sensor nodes: 1) WISP-Mote, which is a sensor mote that employs an Intel WISP passive RFID tag as the WuRx; 2) EH-WISP-Mote, which combines a novel energy harvester with the WISP-Mote; and 3) REACH-Mote, which uses the energy harvester circuit combined with an ultra-low-power pulse generator to trigger the wake-up of the mote. Experimental results show that the wake-up range and wake-up delay for the EH-WISP-Mote are improved compared with the WISP-Mote, while providing the ability to perform both broadcast-based and ID-based wake-ups. On the other hand, the REACH-Mote, which can only provide broadcast-based wake-up, can achieve a much longer wake-up range than any known passive wake-up radio to date, achieving feasible wake-up at a range of up to 37ft. I
Results from the centers for disease control and prevention's predict the 2013-2014 Influenza Season Challenge
Background: Early insights into the timing of the start, peak, and intensity of the influenza season could be useful in planning influenza prevention and control activities. To encourage development and innovation in influenza forecasting, the Centers for Disease Control and Prevention (CDC) organized a challenge to predict the 2013-14 Unites States influenza season. Methods: Challenge contestants were asked to forecast the start, peak, and intensity of the 2013-2014 influenza season at the national level and at any or all Health and Human Services (HHS) region level(s). The challenge ran from December 1, 2013-March 27, 2014; contestants were required to submit 9 biweekly forecasts at the national level to be eligible. The selection of the winner was based on expert evaluation of the methodology used to make the prediction and the accuracy of the prediction as judged against the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet). Results: Nine teams submitted 13 forecasts for all required milestones. The first forecast was due on December 2, 2013; 3/13 forecasts received correctly predicted the start of the influenza season within one week, 1/13 predicted the peak within 1 week, 3/13 predicted the peak ILINet percentage within 1 %, and 4/13 predicted the season duration within 1 week. For the prediction due on December 19, 2013, the number of forecasts that correctly forecasted the peak week increased to 2/13, the peak percentage to 6/13, and the duration of the season to 6/13. As the season progressed, the forecasts became more stable and were closer to the season milestones. Conclusion: Forecasting has become technically feasible, but further efforts are needed to improve forecast accuracy so that policy makers can reliably use these predictions. CDC and challenge contestants plan to build upon the methods developed during this contest to improve the accuracy of influenza forecasts. © 2016 The Author(s)
Covalent stabilization of 2D self-assembled nanostructures on surfaces
The rise of graphene has attracted great interest in low-dimensional materials (0D, 1D and 2D). A joint effort among the different branches of science (chemistry, physics, materials science and related areas) is directed towards the production of new intriguing materials with tuneable graphene-like properties. Promising is the direct synthesis of organic nanostructures on metal surfaces under ultrahigh-vacuum conditions (UHV). Perfect tuning of the reaction conditions, high control of the surface symmetry and of its corrugation, a rich variety of substrate materials are only some of the advantage that UHV may offer. Although several reactions have been tested, it seems clear that to achieve ordered covalent monolayers more complex approaches are needed. In this thesis, the on-surface polymerization of covalent nanostructures has been studied for different coupling reactions, substrate materials and reaction conditions. Scanning tunneling microscopy and X-ray photoelectron spectroscopy are used for the characterization, allowing complementary analysis of molecular structures and chemical states. In particular, thermally activated reactions were used to gradually polymerize the 4,4”-dibromo-terphenyl precursor into poly-paraphenylene wires, through an Ullmann-like reaction scheme on Au(111), and then into graphene nanoribbons, after activation of the C-H bonds. A fine balance between the catalytic activity of the surface, molecular mobility and favourable molecular organization allowed us to get extended and ordered covalent structures. Taking advantage of this synthetic pathway, three different mono-dimensional polymers were obtained, namely poly-paraphenylene and two pyridinic derivatives, with gradually increased nitrogen content. Macroscopically anisotropic samples have been prepared by taking advantage of the vicinal surface templating effect. Using angle resolved photoemission spectroscopy, we reveal that the electronic structure of doped polymers is monotonically downshifted with respect to the metal Fermi level as the pyridine substitution is increased within the molecular scaffold.
Finally, the photochemical activation of different functional groups has been explored. These studies represents a step forward in the application of organic photochemistry to on-surface synthesis, which is currently limited to the use of diacetylene groups, and it opens up new opportunities for using several organic functional groups as photoactive centres for the synthesis of covalent organic frameworks
Polyamine–Drug Conjugates: Do They Boost Drug Activity?
Over the past two decades, the strategy of conjugating polyamine tails with bioactive molecules such as anticancer and antimicrobial agents, as well as antioxidant and neuroprotective scaffolds, has been widely exploited to enhance their pharmacological profile. Polyamine transport is elevated in many pathological conditions, suggesting that the polyamine portion could improve cellular and subcellular uptake of the conjugate via the polyamine transporter system. In this review, we have presented a glimpse on the polyamine conjugate scenario, classified by therapeutic area, of the last decade with the aim of highlighting achievements and fostering future developments
Are There Any Parameters Missing in the Mathematical Models Applied in the Process of Spreading COVID-19?
On 11 March 2020, coronavirus disease 2019 (COVID-19) was declared a pandemic by the World Health Organization (WHO). As of 12.44 GMT on 15 January 2021, it has produced 93,640,296 cases and 2,004,984 deaths. The use of mathematical modelling was applied in Italy, Spain, and UK to help in the prediction of this pandemic. We used equations from general and reduced logistic models to describe the epidemic development phenomenon and the trend over time. We extracted this information from the Italian Ministry of Health, the Spanish Ministry of Health, Consumer Affairs, and Social Welfare, and the UK Statistics Authority from 3 February to 30 April 2020. We estimated that, from the seriousness of the phenomenon, the consequent pathology, and the lethal outcomes, the COVID-19 trend relate to the same classic laws that govern epidemics and their evolution. The curve d(t) helps to obtain information on the duration of the epidemic phenomenon, as its evolution is related to the efficiency and timeliness of the system, control, diagnosis, and treatment. In fact, the analysis of this curve, after acquiring the data of the first three weeks, also favors the advantage to formulate forecast hypotheses on the progress of the epidemic
NeutRAN: An Open RAN Neutral Host Architecture for Zero-Touch RAN and Spectrum Sharing
Obtaining access to exclusive spectrum, cell sites, Radio Access Network
(RAN) equipment, and edge infrastructure imposes major capital expenses to
mobile network operators. A neutral host infrastructure, by which a third-party
company provides RAN services to mobile operators through network
virtualization and slicing techniques, is seen as a promising solution to
decrease these costs. Currently, however, neutral host providers lack automated
and virtualized pipelines for onboarding new tenants and to provide elastic and
on-demand allocation of resources matching operators' requirements. To address
this gap, this paper presents NeutRAN, a zero-touch framework based on the
O-RAN architecture to support applications on neutral hosts and automatic
operator onboarding. NeutRAN builds upon two key components: (i) an
optimization engine to guarantee coverage and to meet quality of service
requirements while accounting for the limited amount of shared spectrum and RAN
nodes, and (ii) a fully virtualized and automated infrastructure that converts
the output of the optimization engine into deployable micro-services to be
executed at RAN nodes and cell sites. NeutRAN was prototyped on an OpenShift
cluster and on a programmable testbed with 4 base stations and 10 users from 3
different tenants. We evaluate its benefits, comparing it to a traditional
license-based RAN where each tenant has dedicated physical and spectrum
resources. We show that NeutRAN can deploy a fully operational neutral
host-based cellular network in around 10 seconds. Experimental results show
that it increases the cumulative network throughput by 2.18x and the per-user
average throughput by 1.73x in networks with shared spectrum blocks of 30 MHz.
NeutRAN provides a 1.77x cumulative throughput gain even when it can only
operate on a shared spectrum block of 10 MHz (one third of the spectrum used in
license-based RANs).Comment: 13 pages, 11 figures, 1 table. IEEE Transactions on Mobile Computing,
August 202
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