Design of Non-Uniformly Spaced Circular Arrays of Parasitic Dipoles for Lower Side Lobe Level with Maximum Directivity

This paper presents a new approach for circular array of parasitic dipoles composed by one active dipole for reduction of side lobe level with maximum directivity including mutual coupling. The desired goal is obtained by changing the spacing between the parasitic elements and length of the parasitic elements while the position and length of driven element is fixed. In addition to it, reflection coefficient (RC) of the driven element is kept closer to the specified value. Matlab based method of moment code is used to evaluate the performance of circular antenna designs generated by QPSO algorithm. Two examples are presented to show the effectiveness of this proposed approach. &nbsp

Applying dissipative dynamical systems to pseudorandom number generation: Equidistribution property and statistical independence of bits at distances up to logarithm of mesh size

The behavior of a family of dissipative dynamical systems representing transformations of two-dimensional torus is studied on a discrete lattice and compared with that of conservative hyperbolic automorphisms of the torus. Applying dissipative dynamical systems to generation of pseudorandom numbers is shown to be advantageous and equidistribution of probabilities for the sequences of bits can be achieved. A new algorithm for generating uniform pseudorandom numbers is proposed. The theory of the generator, which includes proofs of periodic properties and of statistical independence of bits at distances up to logarithm of mesh size, is presented. Extensive statistical testing using available test packages demonstrates excellent results, while the speed of the generator is comparable to other modern generators.Comment: 6 pages, 3 figures, 3 table

Modeling the dynamics of an epidemic under vaccination in two interacting populations

Mathematical modeling of the numerical evolution of infectious diseases has become an important tool for disease control and eradication when possible. Much work has been done on the problem of how a given population is affected by another population when there is mutual interaction. The mere presence of migrant people poses a challenge to whatever health systems are in place in a particular region. Such epidemiological phenomena have been studied extensively, described by mathematical models with suggestions for intervention strategies. The epidemiological effect of migration within the population itself was modeled for sleeping sickness in a paper 1 by Chalvet-Monfray et al. In the case of malaria, there is for instance a study 2 by Tumwiine et al. on the effect of migrating people on a fixed population. The latter two diseases are vector borne. Diseases that propagate without a vector spread perhaps more easily when introduced into a new region. Various studies of models with immigration of infectives have been undertaken for tuberculosis, see for instance 3 by Zhou et al., or the work 4 of Jia et al., and for HIV, see the paper 5 of Naresh et al

A fitted numerical method for singularly perturbed parabolic reaction-diffusion problems

This paper treats a time-dependent singularly perturbed reaction-diffusion problem. We semidiscretize the problem in time by means of the classical backward Euler method. We develop a fitted operator finite difference method (FOFDM) to solve the resulting set of linear problems (one at each time level). We prove that the underlying fitted operator satisfies the maximum principle. This result is then used in the error analysis of the FOFDM. The method is shown to be first order convergent in time and second order convergent in space, uniformly with respect to the perturbation parameter. We test the method on several numerical examples to confirm our theoretical findings.Web of Scienc

Stability of Terrestrial Planets in the Habitable Zone of Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208

We have undertaken a thorough dynamical investigation of five extrasolar planetary systems using extensive numerical experiments. The systems Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208 were examined concerning the question of whether they could host terrestrial like planets in their habitable zones (=HZ). First we investigated the mean motion resonances between fictitious terrestrial planets and the existing gas giants in these five extrasolar systems. Then a fine grid of initial conditions for a potential terrestrial planet within the HZ was chosen for each system, from which the stability of orbits was then assessed by direct integrations over a time interval of 1 million years. The computations were carried out using a Lie-series integration method with an adaptive step size control. This integration method achieves machine precision accuracy in a highly efficient and robust way, requiring no special adjustments when the orbits have large eccentricities. The stability of orbits was examined with a determination of the Renyi entropy, estimated from recurrence plots, and with a more straight forward method based on the maximum eccentricity achieved by the planet over the 1 million year integration. Additionally, the eccentricity is an indication of the habitability of a terrestrial planet in the HZ; any value of e>0.2 produces a significant temperature difference on a planet's surface between apoapse and periapse. The results for possible stable orbits for terrestrial planets in habitable zones for the five systems are summarized as follows: for Gl 777 A nearly the entire HZ is stable, for 47 Uma, HD 72659 and HD 4208 terrestrial planets can survive for a sufficiently long time, while for Gl 614 our results exclude terrestrial planets moving in stable orbits within the HZ.Comment: 14 pages, 18 figures submitted to A&

Intelligent Health Monitoring of Machine Bearings Based on Feature Extraction

This document is the Accepted Manuscript of the following article: Mohammed Chalouli, Nasr-eddine Berrached, and Mouloud Denai, ‘Intelligent Health Monitoring of Machine Bearings Based on Feature Extraction’, Journal of Failure Analysis and Prevention, Vol. 17 (5): 1053-1066, October 2017. Under embargo. Embargo end date: 31 August 2018. The final publication is available at Springer via DOI: https://doi.org/10.1007/s11668-017-0343-y.Finding reliable condition monitoring solutions for large-scale complex systems is currently a major challenge in industrial research. Since fault diagnosis is directly related to the features of a system, there have been many research studies aimed to develop methods for the selection of the relevant features. Moreover, there are no universal features for a particular application domain such as machine diagnosis. For example, in machine bearing fault diagnosis, these features are often selected by an expert or based on previous experience. Thus, for each bearing machine type, the relevant features must be selected. This paper attempts to solve the problem of relevant features identification by building an automatic fault diagnosis process based on relevant feature selection using a data-driven approach. The proposed approach starts with the extraction of the time-domain features from the input signals. Then, a feature reduction algorithm based on cross-correlation filter is applied to reduce the time and cost of the processing. Unsupervised learning mechanism using K-means++ selects the relevant fault features based on the squared Euclidian distance between different health states. Finally, the selected features are used as inputs to a self-organizing map producing our health indicator. The proposed method is tested on roller bearing benchmark datasets.Peer reviewe

Why do people become health workers? Analysis from life histories in 4 post-conflict and post-crisis countries

Sophie Witter - orcid: 0000-0002-7656-6188 https://orcid.org/0000-0002-7656-6188While there is a growing body of literature on how to attract and retain health workers once they are trained, there is much less published on what motivates people to train as health professions in the first place in low- and middle-income countries and what difference this makes to later retention. In this article, we examine patterns in expressed motivation to join the profession across different cadres, based on 103 life history interviews conducted in northern Uganda, Sierra Leone, Cambodia, and Zimbabwe. A rich mix of reported motivations for joining the profession was revealed, including strong influence of personal calling,- exhortations of family and friends, early experiences, and chance factors. Desire for social status and high respect for health professionals were also significant. Economic factors are also important- not just perceptions of future salaries and job security but also more immediate ones, such as low cost or free training. These allowed low-income participants to access the health professions, to which they had shown considerably loyalty. The lessons learned from these cohorts, which had remained in service through periods of conflict and crisis, can influence recruitment and training policies in similar contexts to ensure a resilient health workforce.sch_iih33pub5152pub

Association of metabolic equivalent of task (MET) score in length of stay in hospital following radical cystectomy with urinary diversion:a multi-institutional study

PURPOSE: The Metabolic equivalent of task (MET) score is used in patients’ preoperative functional capacity assessment. It is commonly thought that patients with a higher MET score will have better postoperative outcomes than patients with a lower MET score. However, such a link remains the subject of debate and is yet unvalidated in major urological surgery. This study aimed to explore the association of patients’ MET score with their postoperative outcomes following radical cystectomy. METHODS: We used records-linkage methodology with unique identifiers (Community Health Index/hospital number) and electronic databases to assess postoperative outcomes of patients who had underwent radical cystectomies between 2015 and 2020. The outcome measure was patients’ length of hospital stay. This was compared with multiple basic characteristics such as age, sex, MET score and comorbid conditions. A MET score of less than four (< 4) is taken as the threshold for a poor functional capacity. We conducted unadjusted and adjusted Cox regression analyses for time to discharge against MET score. RESULTS: A total of 126 patients were included in the analysis. Mean age on date of operation was 66.2 (SD 12.2) years and 49 (38.9%) were female. A lower MET score was associated with a statistically significant lower time-dependent risk of hospital discharge (i.e. longer hospital stay) when adjusted for covariates (HR 0.224; 95% CI 0.077–0.652; p = 0.006). Older age (adjusted HR 0.531; 95% CI 0.332–0.848; p = 0.008) and postoperative complications (adjusted HR 0.503; 95% CI 0.323–0.848; p = 0.002) were also found to be associated with longer hospital stay. Other comorbid conditions, BMI, disease staging and 30-day all-cause mortality were statistically insignificant. CONCLUSION: A lower MET score in this cohort of patients was associated with a longer hospital stay length following radical cystectomy with urinary diversion. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11255-021-02813-x

Participatory non-GM cotton breeding to safeguard organic cotton production in India

Due to fast spread of genetically modified (GM) Bt-cotton, organic farmers in India were suddenly exposed to a severe shortage of non-GM seed threatening the organic cotton production. Therefore, organic cotton grower organisations got engaged in decentralized participatory cotton breeding to develop their own locally adapted cultivars and to reintroduce the traditional more robust Desi cotton species. By engaging and training advisors and farmers using participatory methods, they became researchers and breeders. The close collaboration with the textile industry ensures that the market demand is also met. Training of male and female farmers in cultivar selection and seed propagation made them independent from global seed companies. Participatory breeding is an important tool to get prepared for future challenges like climate change and at the same time strengthens the relationship along the value chain. The project can serve as a successful model for other organisations and crops