transmission period
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Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Vamsi K. Amalladinne ◽  
Jamison R. Ebert ◽  
Jean-Francois Chamberland ◽  
Krishna R. Narayanan

Unsourced random access (URA) has emerged as a pragmatic framework for next-generation distributed sensor networks. Within URA, concatenated coding structures are often employed to ensure that the central base station can accurately recover the set of sent codewords during a given transmission period. Many URA algorithms employ independent inner and outer decoders, which can help reduce computational complexity at the expense of a decay in performance. In this article, an enhanced decoding algorithm is presented for a concatenated coding structure consisting of a wide range of inner codes and an outer tree-based code. It is shown that this algorithmic enhancement has the potential to simultaneously improve error performance and decrease the computational complexity of the decoder. This enhanced decoding algorithm is applied to two existing URA algorithms, and the performance benefits of the algorithm are characterized. Findings are supported by numerical simulations.


2021 ◽  
pp. 140349482110562
Author(s):  
Pernille Tanggaard Andersen ◽  
Natasa Loncarevic ◽  
Maria Busk Damgaard ◽  
Mette Winge Jacobsen ◽  
Farida Bassioni-Stamenic ◽  
...  

Aim: This study investigates the non-medical public health and surveillance policies and actions for tackling the community spread of COVID-19 pandemic in Denmark, Serbia and Sweden during the first five months of the pandemic in 2020. Method: The study is inspired by a process-tracing design for case study with a focus on the non-medical measures and surveillance strategies implemented by the three countries. The comprehensive collection and study of national documents formed the basis of the document analysis. Results: The Danish strategy was to prolong the transmission period, preventing high numbers of infected cases from impacting their healthcare capacity. The government’s strategy was characterized by strict governance elements, health guidelines and behavioural recommendations. In Serbia, the main strategy was to prevent the spread and control of the infectious disease by shifting all human and material resources towards the function of controlling the spread. Serbia applied the strictest measures in the fight against coronavirus in relation to other countries in the region and in Europe. The Swedish strategy focused more on recommendations than requirements to motivate the public to modify their behaviours voluntarily. Sweden’s loose pandemic strategy implementation focused on voluntary and stepwise action rather than legislation and compulsory measures. Conclusions: The public health policies and actions implemented to prevent community spread of COVID-19 in Denmark, Serbia and Sweden varied during the first five months of the pandemic. The differences in their response were due to delays in implementation, inconsistencies in perspectives towards the outbreak and the capacity of each country in terms of their pandemic preparedness and response.


Author(s):  
Wasfi Fares ◽  
Kais Ghedira ◽  
Mariem Gdoura ◽  
Anissa Chouikha ◽  
Sondes Haddad-Boubaker ◽  
...  

The method of choice for SARS-CoV-2 variant detection is whole-genome sequencing using next-generation sequencing (NGS) technologies. Resources for this technology remain limited in many low- and middle-income countries, where it is not possible to perform whole-genome sequencing for representative numbers of SARS-CoV-2-positive cases.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Camilla Falcinella ◽  
Marina Allegrini ◽  
Lidia Gazzola ◽  
Giovanni Mulè ◽  
Daniele Tomasoni ◽  
...  

Abstract Background Despite being an uncommon cause of meningoencephalitis, West Nile virus (WNV) recently provoked significant outbreaks throughout Europe. West Nile neuroinvasive disease (WNND) is associated with significant morbidity and mortality in older and compromised individuals, while its diagnosis may be demanding for the clinician. Here discussed are three cases of WNND with a focus on the diagnostic challenges they presented due to atypical clinical presentation and laboratory findings. Case presentation Between July and September 2020 three patients presented to our attention with signs and symptoms compatible with meningoencephalitis. Among routine procedures, they underwent lumbar puncture and imaging. In the absence of microbiological isolates, biological samples were sent for serology and NAATs for WNV. Following diagnosis, the patients gradually recovered and were discharged either home or to rehabilitation facilities. Conclusions The laboratory findings here discussed, in particular CSF parameters, are only partially consistent with those described in the literature, which highlights the need for further research. While serology and NAATs on blood and urine appear the most reliable techniques in the diagnostic work-up of WNND, utility of NAATs on CSF specimens is limited by the kinetics of WNV viremia in biological fluids. This report underlines that WNND should always be included in the differential diagnosis of meningoencephalitis during WNV transmission period.


2021 ◽  
Vol 21 (03) ◽  
Author(s):  
Mohamed Hechmi Jeridi ◽  
Sami Elmadssia ◽  
Tahar Ezzedine

The specificities of the Internet of Things (IoT) require innovative methods to perform routing, owing to the resource limitations of network nodes. The IPv6 routing protocol for low-power and lossy networks ( RPL), as one of these pioneering methods, performs a variety of routing measurements to meet the requirements of some IoT applications, but, does not solve the problems of sudden and intense data traffic caused by the particularity of the other ones. Indeed, it has been observed that such unexpected and excessive data traffic leads to routing instability and traffic congestion in the IoT network. In order to overcome the mentioned shortcomings, we propose a common solution using the mobility of some nodes to reduce system instability and alleviate congestion on the network, to be named: use of mobile node for the Instability & Congestion Alleviation in IoT networks (mob-ICA). Therefore, our contribution consists in overcoming network instability by dynamically regulating the message transmission period to choose the parent nodes according to the speed and direction of the mobile nodes and in reducing congestion by using these nodes to locally create alternative paths to the parental node


Author(s):  
Kritika Bansal ◽  
Pankaj Mukhija

This paper addresses the issue of control of a vehicle platoon system with limited on-board energy and communication resources and subjected to cyber-physical attacks. A platoon model for the predecessor-leader following topology under the effect of cyber-attack and time-varying delay is developed. A stochastic type deception attack is considered in this paper at the sensor-controller end of a vehicle. The probability of occurrence of attack is represented using a random variable. In addition, to reduce the usage of resources in a system, a decentralized event-triggering communication mechanism is proposed where each vehicle can decide independently on when to transmit its state to the controller. Further, the criteria for co-designing of control law and triggering parameter ensuring internal stability of the platoon system is developed based on the proposed triggering mechanism. A condition to achieve string stability for the controller is also obtained. Further, to avoid the problem of Zeno phenomena, a lower bound on the transmission period is presented. The effectiveness of the proposed methodology is established through simulation example.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Laidoudi Younes ◽  
Hélène Barré-Cardi ◽  
Samia Bedjaoui ◽  
Nazli Ayhan ◽  
Marie Varloud ◽  
...  

Abstract Background Dirofilaria immitis and Dirofilaria repens are the main causative agents of heartworm disease and subcutaneous dirofilariasis in domestic and wild canids, respectively. Both pathogens have zoonotic potential and are transmitted by mosquitoes. The present study aimed to determine the transmission period, prevalence and diversity of Dirofilaria spp. vectors from endemic areas of Corsica (France). Methods A monthly point data model based on average temperature recorded by four meteorological stations during 2017 was used to calculate the Dirofilaria transmission period. From June to September 2017, female mosquitoes (n = 1802) were captured using Biogents® Sentinel 2 traps lured with carbon dioxide and BG-Lure™ or octanol. Mosquitoes were identified to species level, pooled accordingly, and screened using multiplex real-time qPCR to detect D. immitis and D. repens. Results The monthly point data model showed the possible transmission of Dirofilaria spp. from the third week in May to the last week in October in the studied area. Mosquitoes were identified as Ochlerotatus caspius (n = 1432), Aedes albopictus (n = 199), Culex pipiens sensu lato (n = 165) and Aedes vexans (n = 6) and were grouped into 109 pools (from 1 to 27 specimens, mean 11.4 ± 0.7), of which 16 scored positive for Dirofilaria spp. (i.e., n = 13; estimated infection rate [EIR] = 1.1% for D. immitis and n = 3; EIR = 0.2% for D. repens). Specifically, 6 (i.e., EIR = 3.8%) of 15 pools of Ae. albopictus were positive for D. immitis, 2 of 14 of Cx. pipiens s.l. were positive for D. immitis and D. repens, respectively, and 8 of 77 pools of Oc. caspius were positive for D. immitis (i.e., n = 6; EIR = 0.4%) and D. repens (i.e., 2; EIR = 0.1%). The highest mosquito infection rate was recorded in July (EIR = 2.5%), then in June (EIR = 1.3%) and September (EIR = 0.6%). Conclusions The data suggest that both Dirofilaria species are endemic and occur possibly in sympatry in the studied area in Corsica, highlighting the need to implement preventive chemoprophylaxis and vector control strategies to reduce the risk of these filarioids in dog and human populations. Graphical Abstract


2021 ◽  
Author(s):  
Seiji Kageyama ◽  
Akeno Tsuneki-Tokunaga ◽  
Kyosuke Kanai

Abstract Close observation of the local transmission of influenza A(H1N1) viruses enabled an estimation of the transmission period of the virus without a mutation. Of 4,448 isolates from 11 consecutive years, 237 isolates could be categorized into 57 strain groups with identical hemagglutinin genes. Transmission of these 57 strains was chased for the maximum duration of an epidemic season. In addition, 35 identical strains were recognized at the study site and other countries within 147 days. Consequently, it can be postulated that once an influenza virus enters a temperate country, the strain rarely mutates until the end of the season.


2021 ◽  
Author(s):  
Adama TRAORE ◽  
Laura DONOVAN ◽  
Benoit SAWADOGO ◽  
Charlotte WARD ◽  
Helen SMITH ◽  
...  

Abstract BackgroundSeasonal malaria chemoprevention (SMC) involves administering antimalarial drugs at monthly intervals during the high malaria transmission period to children aged 3 to 59 months as recommended by the World Health Organization. Typically, a full SMC course is administered over four monthly cycles from July to October, coinciding with the rainy season. However, an analysis of rainfall patterns suggest that the malaria transmission season is now longer and starting as early as June in the south of Burkina Faso, leading to a rise in cases prior to the first cycle. This study assessed the acceptability and feasibility of extending SMC from four to five cycles to coincide with the earlier rainy season in Mangodara health district.MethodsThe mixed-methods study was conducted between July and November 2019. Quantitative data were collected through end-of-cycle and end-of-round household surveys to determine the effect of the additional cycle on the coverage of SMC in Mangodara. The data were then compared with 22 other districts where SMC was implemented by Malaria Consortium. Eight focus group discussions were conducted with caregivers and community distributors and 11 key informant interviews with community, programme and national-level stakeholders. These aimed to determine perceptions of the acceptability and feasibility of extending SMC to five cycles.Results The extension was perceived as acceptable by caregivers, community distributors and stakeholders due to the positive impact on the health of children under five. However, many community distributors expressed concern over the feasibility, mainly due to the clash with farming activities in June. Stakeholders highlighted the need for more evidence on the impact of the additional cycle on parasite resistance prior to scale-up. End-of-cycle survey data showed no difference in coverage between five SMC cycles in Mangodara and four cycles in the 22 comparison districts.Conclusions The additional cycle should begin early in the day in order to not coincide with the agricultural activities of community distributors. Continuous sensitisation at community level is critical for the sustainability of SMC and acceptance of an additional cycle. Further studies are required to understand the effectiveness, including cost-effectiveness, of tailoring SMC according to the rainy season.


2021 ◽  
Author(s):  
Stephan Gehring ◽  
Omar Okasha ◽  
Frank Kowalzik ◽  
Tobias Engelmann ◽  
Daniel Schreiner ◽  
...  

Abstract BackgroundHealthcare workers (HCWs) are at increased risk of SARS-CoV-2 infection. We assessed incidence of SARS-CoV-2 infection and COVID-19 before the roll out of COVID-19 vaccines in a cohort of HCWs in Mainz, Germany.MethodsUsing prospective observational cohort design, antibody status was assessed at baseline and every 6 weeks (±2 weeks). Daily self-reported COVID-19 symptoms were collected using a smartphone application. Symptomatic HCWs were tested using RT-PCR. We estimated symptomatic and asymptomatic SARS-CoV-2 infection rates based on two case definitions of varying sensitivity and specificity.Results3664 HCWs were enrolled with a median follow-up of 101 days. The seroprevalence of anti-SARS-CoV-2 antibodies increased from 2.7% at baseline to 3.8%, with the number of seroconversions (65) outweighing seroreversions (26) by end of follow-up. Among HCWs who seroconverted, 12 (~19%) did not report any symptoms. The estimated incidence rate was 4.5 per 1000 person-months, but none the incident cases developed severe disease. Anti-SARS-CoV-2 antibodies fell below diagnostic cut-off value in a third of those positive at baseline and in one incident case.ConclusionsWe observed increasing COVID-19 rates among HCWs during an accelerated community transmission period, with relatively lower rate of asymptomatic infections. Our findings indicate a relatively long-lasting humoral immune response following natural infection.


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