Neural Network Control of a Laboratory Magnetic Levitator

Magnetic levitation (maglev) systems are nowadays employed in applications ranging from non-contact bearings and vibration isolation of sensitive machinery to high-speed passenger trains. In this chapter a mathematical model of a laboratory maglev system was derived using the Lagrangian approach. A linear pole-placement controller was designed on the basis of specifications on peak overshoot and settling time. A 3-layer feed-forward Artificial Neural Network (ANN) controller comprising 3-input nodes, a 5-neuron hidden layer, and 1-neuron output layer was trained using the linear state feedback controller with a random reference signal. Simulations to investigate the robustness of the ANN control scheme with respect to parameter variations, reference step input magnitude variations, and sinusoidal input tracking were carried out using SIMULINK. The obtained simulation results show that the ANN controller is robust with respect to good positioning accuracy

Spectroscopic source redshifts and parameter constraints from weak lensing and the cosmic microwave background

Weak lensing is a potentially robust and model-independent cosmological probe, but its accuracy is dependent on knowledge of the redshift distribution of the source galaxies used. The most robust way to determine the redshift distribution is via spectroscopy of a subsample of the source galaxies. We forecast constraints from combining cosmic microwave background (CMB) anisotropies with cosmic shear using a spectroscopically determined redshift distribution, varying the number of spectra Nspec obtained from 64 to [infinity]. The source redshift distribution is expanded in a Fourier series, and the amplitudes of each mode are considered as parameters to be constrained via both the spectroscopic and weak lensing data. We assume independent source redshifts, and consider in what circumstances this is a good approximation (the sources are clustered and for narrow spectroscopic surveys with many objects this results in the redshifts being correlated). It is found that for the surveys considered and for a prior of 0.04 on the calibration parameters, the addition of redshift information makes significant improvements on the constraints on the cosmological parameters; however, beyond Nspec ~ few × 10^3 the addition of further spectra will make only a very small improvement to the cosmological parameters. We find that a better calibration makes large Nspec more useful. Using an eigenvector analysis, we find that the improvement continues with even higher Nspec, but not in directions that dominate the uncertainties on the standard cosmological parameters

Global epidemiology of capsular group W meningococcal disease, 1970-2014: emergence and persistence of hypervirulent ST-11 lineage

Following an outbreak in Mecca Saudi Arabia in 2000, meningococcal strains expressing capsular group W (W) emerged as a major cause of invasive meningococcal disease (IMD) worldwide. This essay presents a critical review of studies reporting IMD surveillance data spanning four decades and places in context the recent findings of WGS studies to the epidemiology of group W IMD. This report will be of use to Public Health experts in several countries currently facing a rise in number of W cc11 cases and persistence of sporadic group W cases. The Saudi Arabian outbreak strain (Hajj clone) belonging to the ST-11 clonal complex (cc11) is similar to W cc11 causing occasional sporadic disease before 2000. Since 2000, W cc11 has caused large meningococcal disease epidemics in the African meningitis belt and endemic disease in South America, Europe and China. Traditional molecular epidemiologic typing suggested that a majority of current W cc11 burden represented global spread of the Hajj clone. However, recent whole genome sequencing (WGS) analyses revealed significant genetic heterogeneity among global W cc11 strains. While continued spread of Hajj-related strains occurs in the Middle East, the meningitis belt and South Africa have co-circulation of the Hajj clone and other unrelated W cc11 strains and South America, the UK and France share a genetically distinct W c11 strain. Other W lineages persist in low numbers in Europe, North America and the meningitis belt. In summary, WGS is helping to unravel the complex genomic epidemiology of group W meningococcal strains. Wider application of WGS and strengthening of global IMD surveillance is necessary to monitor the continued evolution of group W lineages. There is need for a vaccine that is protective against group W in the meningitis belt. Public Health relevance: This essay presents a critical review of studies reporting IMD surveillance data spanning four decades and places in context the recent findings of WGS studies to the epidemiology of group W IMD. This report will be of use to Public Health surveillance and policy professionals in several countries currently facing a rise in number of W cc11 cases and persistence of sporadic group W cases. Data presented in this review also provides evidence in support of introduction of group W in the African meningitis belt

Global emergence and persistence of hypervirulent capsular group W sequence type (ST)-11 Neisseria meningitidis

Neisseria meningitidis is a leading bacterial cause of sepsis and meningitis globally. Beginning with an epidemic among Hajj pilgrims in 2000, capsular group W (W) sequence type (ST) 11 emerged as a leading cause of epidemic meningitis in the African ‘meningitis belt’ and endemic cases in South America, Europe, Middle East and China. Previous genotyping studies were unable to reliably discriminate less virulent W ST-11 strains in circulation since 1970 from the Hajj epidemic strain (Hajj clone). It is also unclear what proportion of more recent W ST-11 disease clusters were caused by direct descendants of the Hajj clone. This work analyzes whole genome sequences of a global collection of over 250 meningococcal strains isolated from patients with invasive meningococcal disease globally from 1970 to 2014 using phylogenetic analyses, detailed examination of the capsule gene cluster (cps) and genes encoding major surface antigens. We found that all W ST-11 strains were descendants of an ancestral strain that had undergone unique capsular switching events. We identified two distinct, conserved, recombination events within W ST-11 cps genes with W ST-22 and Y ST-23 as most likely donor lineages. In addition, the Hajj clone and its descendants were distinct from other W ST-11 strains in that they shared a common antigen gene profile and had undergone further recombination involving virulence genes encoding factor H binding protein (fHbp), nitric oxide reductase (nor), and nitrite reductase (aniA). These data suggest that the W ST-11 capsular switch involved two separate recombination events and that current global W ST-11 meningococcal disease is caused by strains bearing this capsular switch. Emergence of the Hajj clone may be related to recent acquisition of a distinct antigen-encoding gene profile and variations in meningococcal virulence genes. This study resolves questions about the Hajj epidemic strain that were unanswered for 15 years. Furthermore, the findings of this study help illuminate genomic factors associated with emergence and evolution virulent meningococcal strains. Public Health significance: This dissertation provides genomic markers that reliably distinguish epidemic from sporadic W ST-11 strains that are applicable to molecular surveillance of N. meningitidis. Data presented in this work also demonstrate the need for a group W vaccine disease in the meningitis belt that can be potentially used beyond the meningitis belt in South Africa, parts of Latin America, and Europe that are facing the emergence of W ST-11

Do Fish Have Rights in Artisanal Fisheries?

Artisanal fishers in developing world are unaware that fish are capable of suffering or discomfort, though researches have shown that fish do feel pain. Five fish welfare domains have been identified which constitute their rights in their environment. The needs of wild fish are usually provided in their natural, undisturbed and unperturbed aquatic environment, of which the fish will prefer. However, various anthropogenic activities by humans (including artisanal fisheries itself) and some natural perturbations in the watershed, riparian zone, water body of the fish habitat and on the fish tend to take away these needs thereby compromising the fish welfare. These activities include environmental degradation, boat/canoe building, use of motorized engine boats/canoes, use of active and passive fishing gears, obnoxious cultural, religious and social fishing practices, fish harvesting, handling and processing among others. One way to understand the welfare needs of an individual fish is to understand its biology. Poor welfare conditions could then be assessed by how far the individual fish has deviated from the normal conditions. Non-intrusive signs based on the health, behavior, morphological anomalies, swimming, reduction in population and growth, outbreak of parasitic infections, injuries and loss of condition can be used to assess fish whose welfare has been compromised. Artisanal fishers should not only be concerned with catch, but, also the welfare of the fish being caught. This is because if the welfare of the fish is compromised, it is going to definitely affect the catch. As indispensable as fish is to humans, humans should not derive its pleasure at the expense of fish suffering. Human activities that impinge on the welfare of wild fish may not necessarily be stopped, but at least minimized in order to have continued sustainable artisanal exploitation of the fisheries

A Review of TV White Space Technology and its Deployments in Africa

The emergence of bandwidth-driven applications in the current wireless communication environment is driving a paradigm shift from the conventional fixed spectrum assignment policy to intelligent and dynamic spectrum access. Practical demands for efficient spectrum utilization have continued to drive the development of TV white space technology to provide affordable and reliable wireless connectivity. It is envisaged that transition from analogue transmission to Digital Terrestrial Television (DTT) creates more spectrum opportunity for TV white space access and regulatory agencies of many countries had begun to explore this opportunity to address spectrum scarcity. To convey the evolutionary trends in the development of TV white space technology, this paper presents a comprehensive review on the contemporary approaches to TV white space technology and practical deployments of pilot projects in Africa. The paper outlines the activities in TV white space technology, which include regulations and standardization, commercial trials, research challenges, open issues and future research directions. Furthermore, it also provides an overview of the current industrial trends in TV white space technology which demonstrates that cognitive radio as an enabling technology for TV white space technology