148 research outputs found
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Optimisation of a propagation model for last mile connectivity with low altitude platforms using machine learning
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonOur related research review on propagation models reveals six factors that are significant in last mile connectivity via LAP: path loss, elevation angle, LAP altitude, coverage area, power consumption, operation frequency, interference, and antenna type. These factors can help with monitoring system performance, network planning, coverage footprint, receivers’ line-of-sight, quality of service requirements, and data rates which may all vary in response to geomorphology characteristics. Several competing propagation models have been proposed over the years but whilst they collectively raise many shortcomings such as limited altitude up to few tens of meters, lack of cover across different environments, low perdition accuracy they also exhibit several advantages. Four propagation models, which are representatives of their types, have been selected since they exhibit advantages in relation to high altitude, wide coverage range, adaption across different terrains. In addition, all four have been extensively deployed in the past and as a result their correction factors have evolved over the years to yield extremely accurate results which makes the development and evaluation aspects of this research very precise. The four models are: ITU-R P.529-3, Okumura, Hata-Davidson, and ATG. The aim of this doctoral research is to design a new propagation model for last-mile connectivity using LAPs technology as an alternative to aerial base station that includes all six factors but does not exhibit any of the shortcomings of existing models. The new propagation model evolves from existing models using machine learning. The four models are first adapted to include the elevation angle alongside the multiple-input multiple-output diversity gain, our first novelty in propagation modelling. The four adapted models are then used as input in a Neural Network framework and their parameters are clustered in a Self-Organizing-Map using a minimax technique. The framework evolves an optimal propagation model that represents the main research contribution of this research. The optimal propagation model is deployed in two proof-of-concept applications, a wireless sensor network, and a cellular structure. The performance of the optimal model is evaluated and then validated against that of the four adapted models first in relation to predictions reported in the literature and then in the context of the two proof-of-concept applications. The predictions of the optimised model are significantly improved in comparison to those of the four adapted propagation models. Each of the two proof-of-concept applications also represent a research novelty.The Royal Saudi Embassy and the Saudi Cultural Bureau in London, and Taif University in the Kingdom of Saudi Arabia
Extensive variation in the intelectin gene family in laboratory and wild mouse strains
Intelectins are a family of multimeric secreted proteins that bind microbe-specific glycans. Both genetic and functional studies have suggested that intelectins have an important role in innate immunity and are involved in the etiology of various human diseases, including inflammatory bowel disease. Experiments investigating the role of intelectins in human disease using mouse models are limited by the fact that there is not a clear one-to-one relationship between intelectin genes in humans and mice, and that the number of intelectin genes varies between different mouse strains. In this study we show by gene sequence and gene expression analysis that human intelectin-1 (ITLN1) has multiple orthologues in mice, including a functional homologue Itln1; however, human intelectin-2 has no such orthologue or homologue. We confirm that all sub-strains of the C57 mouse strain have a large deletion resulting in retention of only one intelectin gene, Itln1. The majority of laboratory strains have a full complement of six intelectin genes, except CAST, SPRET, SKIVE, MOLF and PANCEVO strains, which are derived from different mouse species/subspecies and encode different complements of intelectin genes. In wild mice, intelectin deletions are polymorphic in Mus musculus castaneus and Mus musculus domesticus. Further sequence analysis shows that Itln3 and Itln5 are polymorphic pseudogenes due to premature truncating mutations, and that mouse Itln1 has undergone recent adaptive evolution. Taken together, our study shows extensive diversity in intelectin genes in both laboratory and wild-mice, suggesting a pattern of birth-and-death evolution. In addition, our data provide a foundation for further experimental investigation of the role of intelectins in disease
Some New Estimates of Hermite–Hadamard, Ostrowski and Jensen-Type Inclusions for h-Convex Stochastic Process via Interval-Valued Functions
Mathematical programming and optimization problems related to fluid dynamics are heavily influenced by stochastic processes associated with integral and variational inequalities. Furthermore, symmetry and convexity are intrinsically related. Over the last few years, both have become increasingly interconnected so that we can learn from one and apply it to the other. The objective of this note is to convert ordinary stochastic processes into interval stochastic processes due to the wide range of applications in various disciplines. We have developed Hermite–Hadamard ((Formula presented.)), Ostrowski-, and Jensen-type inequalities using interval h-convex stochastic processes. Our main results can be applied to a variety of new and well-known outcomes as specific situations. The results of this study are expected to stimulate future research on inequalities using fractional and fuzzy integral operators. Furthermore, we validate our main findings by providing some non-trivial examples. To demonstrate their general properties, we illustrate the connections between the examined results and those that have already been published. The results discussed in this article can be seen as improvements and refinements to results that have already been published. This is a fascinating subject that can be investigated in the future to identify equivalent inequalities for various convexity types. © 2023 by the authors.Deanship of Scientific Research, King Khalid University: RGP2/366/44The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through large group Research Project under grant number RGP2/366/44
Applying Best Practices for The Prevention of Surgical Site Infection (SSI) and Reducing Risk Factors for Patients: Meta-Analysis Theoretical Review
This study aimed at providing a comprehensive range of evidence-based recommendations for interventions to be applied during the pre-, intra- and postoperative periods for the prevention of the surgical site infection SSI, while also considering aspects related to resource availability and values and preferences. An initial search identified more than 200 titles published in 2006-2017 as relevant for data extraction, the researchers dealt with the extracted information included study design and methodology, reported cumulative incidence and post-surgical time until onset of SSI, and odds ratios and associated variability for all factors considered in univariate and/or multivariable analyses. And then the study recommended the best producers for reducing the risk factors for patients by conducting the findings of the meta-analysis theoretical review. Keywords: Surgical Site Infection, Risk Factors, Best Practices, Patient
Spinal Surgery Patients’ Preoperative Education Effects
Preoperative patient education (PE) has been used by many institutions to deal with patient anxiety, pain control, and overall satisfaction. Although the literature suggests PE’s effectiveness in joint reconstruction, data are missing in spinal surgery. This research retrospectively analyzed patients having elective spinal surgery who underwent PE (spine pre-care class) from January 2016 to June 2016. Of the 160 patients surveyed, (36.5%) attended the class whereas (63.5%) did not. Results of the participants in the pre-care class, 86% were satisfied with their pain management versus 73% in the control group. There was also a trend for better overall satisfaction in the pre-care class group (88.1% vs 85, multiple regression analysis). Elderly women tend to be less satisfied with pain management and overall treatment. The study concluded that the implementation of PE has had a positive impact on patient satisfaction, especially in terms of pain management.
Access and utilisation of primary health care services comparing urban and rural areas of Riyadh Providence, Kingdom of Saudi Arabia
The Kingdom of Saudi Arabia (KSA) has seen an increase in chronic diseases. International evidence suggests that early intervention is the best approach to reduce the burden of chronic disease. However, the limited research available suggests that health care access remains unequal, with rural populations having the poorest access to and utilisation of primary health care centres and, consequently, the poorest health outcomes. This study aimed to examine the factors influencing the access to and utilisation of primary health care centres in urban and rural areas of Riyadh province of the KSA
Role of L- glutamine and crizanlizumab in sickle cell anaemia painful crisis reduction
BackgroundPatients with sickle cell disease, frequently suffer from intense painful episodes. Till recently hydroxyurea was the only available medical therapy that approved for reduction of painful episodes.AimsTo summarize the available data from randomized controlled trials that aim to evaluate the efficacy of newly approved L-glutamine (alters redox state of red blood cells [RBCs]) and crizanlizumab ((anti-P-selectin)) on vaso-occlusive episodes in Sickle cell disease patients.Methods PubMed, Google Scholar, and EBSCO databases were systematically search for relevant articles. The terms L-glutamine, sickle cell disease, sickle cell anaemia, crizanlizumab and vaso-occlusive episodes were used.Results Out of Four-hundred seventy-two records, only three fulfilled the inclusion criteria. Two trials were aimed to evaluate the efficacy of L-glutamine therapy on the frequency of painful crises in sickle cell anaemia patients. Both studies showed that L-glutamine therapy significantly reduce the frequency of VOEs. Only one trial examined the ability of crizanlizumab on VOEs reduction, and showed crizanlizumab successful reduce the occurrence of VOEs.ConclusionNewer agent with different mechanism of action, such as L-glutamine, and crizanlizumab may consider if hydroxyurea not effective or not tolerable
Direct observation of DNA threading in flap endonuclease complexes
Maintenance of genome integrity requires that branched nucleic acid molecules are
accurately processed to produce double-helical DNA. Flap endonucleases are essential
enzymes that trim such branched molecules generated by Okazaki fragment synthesis during
replication. Here, we report crystal structures of bacteriophage T5 flap endonuclease in
complexes with intact DNA substrates, and products, at resolutions of 1.9–2.2 Å. They reveal
single-stranded DNA threading through a hole in the enzyme enclosed by an inverted Vshaped
helical arch straddling the active site. Residues lining the hole induce an unusual
barb-like conformation in the DNA substrate juxtaposing the scissile phosphate and essential
catalytic metal ions. A series of complexes and biochemical analyses show how the
substrate’s single-stranded branch approaches, threads through, and finally emerges on the far
side of the enzyme. Our studies suggest that substrate recognition involves an unusual “flycasting,
thread, bend and barb” mechanis
Understanding the risk and protective factors associated with obesity amongst Libyan adults - a qualitative study
BACKGROUND:
There are a range of multifaceted behavioural and societal factors that combine to contribute to the causes of obesity. However, it is not yet known how particularly countries' cultural norms are contributing to the global obesity epidemic. Despite obesity reaching epidemic proportions in Libya, since the discovery of oil in 1959, there is a lack of information about obesity in Libyan adults. This study sought to explore the views of key informants about the risk and protective factors associated with obesity among Libyan men and women.
METHODS:
A series of qualitative semi-structured interviews were conducted with Libyan healthcare professionals and community leaders.
RESULTS:
Eleven main themes (risk and protective factors) were identified, specifically: socio-demographic and biological factors, socioeconomic status, unhealthy eating behaviours, knowledge about obesity, social-cultural influences, Libya's healthcare facilities, physical activity and the effect of the neighbourhood environment, sedentary behaviour, Libyan food-subsidy policy, and suggestions for preventing and controlling obesity.
CONCLUSIONS:
Key recommendations are that an electronic health information system needs to be implemented and awareness about obesity and its causes and consequences needs to be raised among the public in order to dispel the many myths and misconceptions held by Libyans about obesity. The current political instability within Libya is contributing to a less-active lifestyle for the population due to security concerns and the impact of curfews. Our findings have implications for Libyan health policy and highlight the urgent need for action towards mitigating against the obesity epidemic in Libya
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