Neighbourhood-aware counter-based broadcast scheme for wireless ad hoc networks

Broadcasting is a vital operation in mobile ad hoc networks (MANETs) and it is crucial to enhance its efficiency to ensure successful deployment. Although flooding is ideal for broadcast operations due to its simplicity and high reachability it suffers from high packet collision which can degrade network performance severely. Counter-based broadcast schemes have been introduced to alleviate the limitations of flooding. This study introduces an enhancement to counter-based broadcast by adjusting the threshold value and the Random Assessment Delay (RAD) using minimal neighbourhood information

Stable Infrastructure-based Routing for Intelligent Transportation Systems

Intelligent Transportation Systems (ITSs) have been instrumental in reshaping transportation towards safer roads, seamless logistics, and digital business-oriented services under the umbrella of smart city platforms. Undoubtedly, ITS applications will demand stable routing protocols that not only focus on Inter-Vehicle Communications but also on providing a fast, reliable and secure interface to the infrastructure. In this paper, we propose a novel stable infrastructure- based routing protocol for urban VANETs. It enables vehicles proactively to maintain fresh routes towards Road-Side Units (RSUs) while reactively discovering routes to nearby vehicles. It builds routes from highly stable connected intersections using a selection policy which uses a new intersection stability metric. Simulation experiments performed with accurate mobility and propagation models have confirmed the efficiency of the new protocol and its adaptability to continuously changing network status in the urban environment

Performance evaluation of a new end-to-end traffic-aware routing in MANETs

There has been a lot of research effort on developing reactive routing algorithms for mobile ad hoc networks (MANETs) over the past few years. Most of these algorithms consider finding the shortest path from source to destination in building a route. However, this can lead to some network nodes being more overloaded than the others. In MANETs resources, such as node power and channel bandwidth are often at a premium and, therefore, it is important to optimise their use as much as possible. Consequently, a traffic-aware technique to distribute the load is very desirable in order to make good utilisation of nodes' resources. Therefore a number of end-to-end traffic aware techniques have been proposed for reactive routing protocols to deal with this challenging issue. In this paper we contribute to this research effort by proposing a new traffic aware technique that can overcome the limitations of the existing methods. Results from an extensive comparative evaluation show that the new technique has superior performance over similar existing end-to-end techniques in terms of the achieved throughput, end-to-end delay and routing overhead

Performance study of end-to-end traffic-aware routing

There has been a lot research effort on developing reactive routing algorithms for mobile ad hoc networks (MANETs) over the past few years. Most of these algorithms consider finding the shortest path from source to destination in building a route. However, this can lead to some network nodes being more overloaded than the others. In MANETs resources, such as node power and channel bandwidth are often at a premium and, therefore, it is important to optimise their use as much as possible. Consequently, a traffic-aware technique to distribute the load is very desirable in order to make good utilisation of nodes' resources. A number of traffic aware techniques have recently been proposed and can be classified into two categories: end-to-end and on-the-spot. The performance merits of the existing end-to-end traffic aware techniques have been analysed and compared against traditional routing algorithms. There has also been a performance comparison among the existing on-the-spot techniques. However, there has so far been no similar study that evaluates and compares the relative performance merits of end-to-end techniques. In this paper, we describe an extensive performance evaluation of two end-to-end techniques, based on degree of nodal activity and traffic density, using measures based on throughput, end-to-end delay and routing overhead

Orbital Fluctuation-Induced Triplet Superconductivity : Mechanism of Superconductivity in Sr2RuO4{\rm Sr}_{2}{\rm RuO}_{4}

The mechanism of superconductivity in ${\rm Sr}_{2}{\rm RuO}_{4}$ is studied using a degenerate Hubbard model within the weak coupling theory. When the system approaches the orbital instability which is realized due to increasing the on-site Coulomb interaction between the electrons in the different orbitals, it is shown that the triplet superconductivity appears. This superconducting mechanism is only available in orbitally degenerate systems with multiple Fermi surfaces.Comment: 5 pages, 4 figure

The risk of miscarriage following COVID-19 vaccination: a systematic review and meta-analysis

STUDY QUESTION: What is the risk of miscarriage among pregnant women who received any of the COVID-19 vaccines? SUMMARY ANSWER: There is no evidence that COVID-19 vaccines are associated with an increased risk of miscarriage. WHAT IS KNOWN ALREADY: In response to the COVID-19 pandemic, the mass roll-out of vaccines helped to boost herd immunity and reduced hospital admissions, morbidity and mortality. Still, many were concerned about the safety of vaccinesfor pregnancy, which may have limited their uptake among pregnant women and those planning a pregnancy. STUDY DESIGN, SIZE, DURATION: For this systematic review and meta-analysis, we searched MEDLINE, EMBASE and Cochrane CENTRAL from inception until June 2022 using a combination of keywords and MeSH terms. PARTICIPANTS/MATERIALS, SETTING, METHODS: We included observational and interventional studies that enrolled pregnant women and evaluated any of the available COVID-19 vaccines compared to placebo or no vaccination. We primarily reported on miscarriage in addition to ongoing pregnancy and/or live birth. MAIN RESULTS AND THE ROLE OF CHANCE: We included data from 21 studies (5 randomised trials and 16 observational studies) reporting on 149,685 women. The pooled rate of miscarriage among women who received a COVID-19 vaccine was 9% (n = 147,49/123,185, 95%CI 0.05-0.14). Compared to those who received a placebo or no vaccination, women who received a COVID-19 vaccine did not have a higher risk of miscarriage (RR 1.07, 95%CI 0.89-1.28, I2 35.8%) and had comparable rates for ongoing pregnancy or live birth (RR 1.00, 95%CI 0.97-1.03, I2 10.72%). LIMITATIONS, REASONS FOR CAUTION: Our analysis was limited to observational evidence with varied reporting, high heterogeneity and risk of bias across included studies, which may limit the generalisability and confidence in our findings. WIDER IMPLICATIONS OF THE FINDINGS: COVID-19 vaccines are not associated with an increase in the risk of miscarriage or reduced rates of ongoing pregnancy or live birth among women of reproductive age. The current evidence remains limited and larger population studies are needed to further evaluate the effectiveness and safety of COVID-19 in pregnancy. STUDY FUNDING/COMPETING INTEREST: No direct funding was provided to support this work. MPR is funded by the Medical Research Council Centre for Reproductive Heath Grant No: MR/N022556/1. BHA hold a personal development award from the National Institute of Health Research in the UK. All authors declare no conflict of interest. REGISTRATION NUMBER: CRD42021289098

A New Load-Balancing Aware Objective Function for RPL’s IoT Networks

The IPv6 Routing Protocol for Low-power and Lossy Networks (RPL) has been recently standardized as the de facto solution for routing in the context of the emerging Internet of Things (IoT) paradigm. RPL, along with other standards, has provided a baseline framework for IoT that has helped advance communications in the world of embedded resource-constrained networks. However, RPL still suffers from issues that may limit its efficiency such as the absence of an efficient load-balancing primitive. In this study, we show how RPL suffers from a load-balancing problem that may harm both the reliability of the protocol and its network lifetime. To address this problem, a novel load-balancing scheme is introduced that significantly enhances the reliability of RPL and fosters the protocol’s efficiency in terms of power consumption

Novice and Expert Observer Accuracy of the Threshold Wheelchair Skill: A Pilot Eye-Tracking Study

Background: Moving a wheelchair over a low threshold is an entry-level mobility skill. Observation is critical to the assessment and training of this skill. The primary objective of this exploratory pilot study was to determine if a difference between novice and expert visual attention allocation pattern was linked to the accuracy of rating skill performance and decision confidence. Methods: Twelve expert occupational therapists and nine non-expert occupational therapy students observed 30 first-attempt recordings of able-bodied persons learning the low threshold skill. Randomized recordings included 10 recordings from each rating group of “pass,” “pass with difficulty (pwd), and “fail.” Skill ratings, confidence ratings, time to decision, and SR Eyelink 1000+ monitored eye movements were recorded. Results: No significant group differences were found in the correct identification skill rating, though significant relationships were found with experts rating higher confidence in their decision-making and generally faster reaction times. While trends of eye movements differences were found between groups, only the number of areas of interest viewed in pwd videos was a potential rating correctness predictor. Conclusion: Improved confidence in decision-making did not mean improved assessment accuracy. The pwd video stimuli created the opportunity for assessing observation patterns differences. Further study is recommended

Effects of Cetuximab and Erlotinib on the behaviour of cancer stem cells in head and neck squamous cell carcinoma.

The therapeutic responses of many solid tumours to chemo- and radio-therapies are far from fully effective but therapies targeting malignancy-related cellular changes show promise for further control. In head and neck squamous cell carcinoma, the epidermal growth factor receptor (EGFR) is commonly overexpressed and investigation of agents that block this receptor indicate a limited response when used alone but an ability to enhance the actions of other drugs. The hierarchical stem cell patterns present in tumours generate cellular heterogeneity and this is further complicated by cancer stem cells (CSC) shifting between epithelial (Epi-CSC) and mesenchymal (EMT-CSC) states. To clarify how such heterogeneity influences responses to EGFR blocking, we examined the effects of Cetuximab and Erlotinib on the cell sub-populations in HNSCC cell lines. These agents reduced cell proliferation for all subpopulations but induced little cell death. They did however induce large shifts of cells between the EMT-CSC, Epi-CSC and differentiating cell compartments. Loss of EMT-CSCs reduced cell motility and is expected to reduce invasion and metastasis. EGFR blocking also induced shifts of Epi-CSCs into the differentiating cell compartment which typically has greater sensitivity to chemo/radiation, an effect expected to enhance the overall response of tumour cell populations to adjunctive therapies.This work was supported by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs, Grant number: NC/L00061X/1), by The São Paulo Research Foundation (FAPESP Grant numbers 2014/12658-3 and 2011/21395-8), and by the Barts and The London Charitable Foundation