Good Measure Of Agreement Research Articles

Vicki Funk's legacy continues – The IAPT Small Collections Grant

Vicki Funk's legacy continues – The IAPT Small Collections Grant

Near-term impact of climate variability on yam rot incidence over a humid tropical region: projections in CORDEX-Africa scenarios

AbstractThe global population is projected to be enormous by the mid-21st century, whereas, most essential crops being sustained by the rain-fed agriculture are threatened by climate change. Therefore, the study investigated the projected near-future effect of rainfall variability on rot incidence and yam production in humid tropical Nigeria. Production data from the Food and Agriculture Organization and the Nigeria National Bureau of Statistics showed the significant increasing trend in the annual yam output. The field survey conducted in 2018 showed that the maximum percentage of rot incidence occurred in July. Climate Research Unit observational rainfall data from 1979 to 2018 showed the nonsignificant trend in the interannual rainfall variability; however, it showed low variability and a significant decreasing trend in the July rainfall. A pathogenicity test on yam samples confirmed rot by fungi, bacteria and nematodes as virulent pathogens, whereas, the nutritional qualities of the rotted yams were indicated. Monthly rainfall and rot incidence showed positive correlation (r = 0.84, significant at 99% from t-test). The positive characteristic impact values indicated that increase (decrease) in the monthly rainfall corresponds to increase (decrease) in the magnitude of monthly percentage rot incidence. Thus, the significantly decreasing rainfall reduced the quantity of rot incidence and consequently increased the annual yam production for the period. Selected CoOrdinated Regional Downscaling EXperiment-Africa models and the ensemble mean showed a good measure of agreement with observational rainfall in the historical experiments. The efficiencies of the bias-corrected outputs in the representative concentration pathway (RCP) 4.5 and 8.5 indicated improved ‘reasonable’ performances. Bias-corrected projections of the July rainfall showed an increasing trend in both the RCPs, which indicate a potential increase in rot incidence and the consequent decline in annual yam production. The findings are imperative in sustaining the global food supply.

Comparison of microscopy and PCR for the detection of human Plasmodium species and Plasmodium knowlesi in southern Myanmar

ObjectivesTo determine the distribution of Plasmodium (P) species including Plasmodium knowlesi and to compare the specificity and sensitivity of microscopy with nested PCR in malaria diagnosis. MethodsThe study was conducted in Kawthaung, southern Myanmar. Ninety clinically suspected malaria patients were screened for malaria by Giemsa stained microscopy and confirmed by nested PCR. ResultsAmong the participants, 57 (63.3%) were positive and 33 (36.7%) were negative by microscopy. Of positive samples, 39 (68.4%) were Plasmodium falciparum, 17 (29.8%) Plasmodium vivax and 1 (1.8%) Plasmodium malariae, whereas 59-amplified by PCR were 40 (67.8%), 18 (30.5%) and 1 (1.7%) respectively. PCR amplified 2 microscopy negative samples. Two samples of P. falciparum detected by microscopy were amplified as P. vivax and vice versa. All samples were negative for Plasmodium ovale, P. knowlesi and mixed infections. Microscopy had a very good measure of agreement (κ = 0.95) compared to nested PCR. Sensitivity and specificity of microscopy for diagnosis of P. falciparum were 92.5% (95% CI: 79.6–98.4) and 96.0% (95% CI: 86.3–99.5) respectively, whereas for P. vivax were 83.3% (95% CI: 58.6–96.4) and 97.2% (95% CI: 90.3–99.7). ConclusionsP. knowlesi was not detected by both microscopy and PCR. Giemsa stained microscopy can still be applied as primary method for malaria diagnosis and is considered as gold standard. As to the lower sensitivity of microscopy for vivax malaria, those with previous history of malaria and relapse cases should be diagnosed by RDT or PCR combined with microscopy. Inaccuracy of species diagnosis highlighted the requirement of training and refresher courses for microscopists.

Comparative evaluation of fluorescent in situ hybridization and Giemsa microscopy with quantitative real-time PCR technique in detecting malaria parasites in a holoendemic region of Kenya

BackgroundEarly and accurate diagnosis of malaria is important in treatment as well as in the clinical evaluation of drugs and vaccines. Evaluation of Giemsa-stained smears remains the gold standard for malaria diagnosis, although diagnostic errors and potential bias estimates of protective efficacy have been reported in practice. Plasmodium genus fluorescent in situ hybridization (P-Genus FISH) is a microscopy-based method that uses fluorescent labelled oligonucleotide probes targeted to pathogen specific ribosomal RNA fragments to detect malaria parasites in whole blood. This study sought to evaluate the diagnostic performance of P-Genus FISH alongside Giemsa microscopy compared to quantitative reverse transcription polymerase chain reaction (qRT-PCR) in a clinical setting.MethodFive hundred study participants were recruited prospectively and screened for Plasmodium parasites by P-Genus FISH assay, and Giemsa microscopy. The microscopic methods were performed by two trained personnel and were blinded, and if the results were discordant a third reading was performed as a tie breaker. The diagnostic performance of both methods was evaluated against qRT-PCR as a more sensitive method.ResultsThe number of Plasmodium positive cases was 26.8% by P-Genus FISH, 33.2% by Giemsa microscopy, and 51.2% by qRT-PCR. The three methods had 46.8% concordant results with 61 positive cases and 173 negative cases. Compared to qRT-PCR the sensitivity and specificity of P-Genus FISH assay was 29.3 and 75.8%, respectively, while microscopy had 58.2 and 93.0% respectively. Microscopy had a higher positive and negative predictive values (89.8 and 68.0% respectively) compared to P-Genus FISH (56.0 and 50.5%). In overall, microscopy had a good measure of agreement (76%, k = 0.51) compared to P-Genus FISH (52%, k = 0.05).ConclusionThe diagnostic performance of P-Genus FISH was shown to be inferior to Giemsa microscopy in the clinical samples. This hinders the possible application of the method in the field despite the many advantages of the method especially diagnosis of low parasite density infections. The P-Genus assay has great potential but application of the method in clinical setting would rely on extensive training of microscopist and continuous proficiency testing.

Evaluation of the utility value of three diagnostic methods in the detection of malaria parasites in endemic area

BackgroundMalaria is a debilitating disease with high morbidity and mortality in Africa, commonly caused by different species of the genus Plasmodium in humans. Misdiagnosis is a major challenge in endemic areas because of other disease complications and technical expertise of the medical laboratory staff. Microscopic method using Giemsa-stained blood film has been the mainstay of diagnosis of malaria. However, since 1993 when rapid diagnostic test (RDT) kits were introduced, they have proved to be effective in the diagnosis of malaria. This study was aimed at comparing the accuracy of microscopy and RDTs in the diagnosis of malaria using nested PCR as the reference standard. Four hundred and twenty (420) venous blood specimens were collected from patients attending different General Hospitals in Ebonyi State with clinical symptoms of malaria. The samples were tested with Giemsa-stained microscopy and three RDTs. Fifty specimens were randomly selected for molecular analysis.ResultsUsing different diagnostic methods, the prevalence of malaria among the subjects studied was 25.95% as detected by microscopy, prevalence found among the RDTs was 22.90, 15.20 and 54.80% for Carestart, SD Bioline PF and SD Bioline PF/PV, respectively. Molecular assay yielded a prevalence of 32%. The major specie identified was Plasmodium falciparum; there was co-infection of P. falciparum with Plasmodium malariae and Plasmodium ovale. The sensitivity and specificity of microscopy was 50.00 and 70.59% while that of the RDTs were (25.00 and 85.29%), (25.00 and 94.12%) and (68.75 and 52.94%) for Carestart, SD Bioline PF and SD Bioline PF/PV, respectively. Cohen’s kappa coefficient was used to measure the level of agreement of the methods with nested PCR. Microscopy showed a moderate measure of agreement (k = 0.491), Carestart showed a good measure of agreement (k = 0.611), SD Bioline PF showed a fair measure of agreement (k = 0.226) while SD Bioline PF/PV showed a poor measure of agreement (k = 0.172).ConclusionsThis study recommends that the policy of malaria diagnosis be changed such that the routine diagnosis of malaria is done by a combination of both microscopy and a RDT kit of high sensitivity and specificity so as to complement the errors associated with either of the methods. The finding of P. ovale in the study area necessitates an expanded molecular epidemiology of malaria within the study area.

Finite element analysis on the effect of workpiece geometry on the quenching of ST50 steel

The finite element method (FEM) is employed to investigate the residual stress state and the variation of internal stresses in ST50 steel quenched from 600 to 0°C. Three different geometrical shapes of model were used, namely cylinder, cone and pyramid-shaped cone. Thermal analysis is first performed to obtain the cooling curves for the core and surface of the models, and this is followed by a full structural analysis. The results of the cylinder bar obtained from the computer simulation are compared with those experimentally determined values that are available in the literature and there appears to be a good measure of agreement. The study found that at the initial stages of the quenching process, the residual stresses were tensile at the surface and compressive in the core, however, towards the end of the quenching process, the tensile residual stresses switched to the core and compressive residual stresses at the surface. Under the same quenching conditions, if the models with different geometrical shape were tested, it has been found that the geometry has significant effect on the distribution and the magnitudes of the residual stress. Although the cylinder and the cone were different in shapes, but the residual stress state were not much in difference. Only when the cone turn into pyramid-shaped cone, the results were different and higher values of internal residual stress.

Non-Manipulative Estimates of Competition Coefficients in a Montane Grassland Community

1. A method is given for estimating competition coefficients in multispecies grassland communities without manipulation, using the natural turnover of individuals at a fine spatial scale. The method requires a detailed map of the spatial distribution of plants documented at several points in time, and uses non-linear regression of the local density of the plants on their densities in small neighbourhoods at a previous time. 2. The method is tested by generating realizations of two spatiotemporal stochastic processes for which the true parameter values are known. It is shown that non-linear regression successfully recovers the major features of the competition matrices. 3. The method is applied to a montane grassland dominated by four species of grass, for which spatial data on four plots are available for an 11-year period, and for which results of manipulation experiments are also available. 4. The results show that competitive interactions between species are as strong as interactions within species. There are strong asymmetries in the competition coefficients of species pairs, but little sign of species specificity. Intransitivities of the interaction matrix are not evident. The competition coefficients obtained show a good measure of agreement with the results of manipulation experiments that have been carried out on the community. 5. It is argued that non-manipulative methods of the kind described here hold a useful key to understanding interactions in plant communities.

Coupling in Dielectric Waveguide Systems

Abstract A method devised by Arnaud for evaluating the coupling between two parallel dielectric waveguides has been extended to an arbitrary number of guides. Expressions for the propagation coefficients of the system have been found and calculated numerically for six identical guides uniformly distributed in a circular structure with and without a central core. A good measure of agreement has been found between the results obtained by this method and those obtained by other methods. This method is simple because it requires the evaluation of a line integral outside the guides, instead of a surface integral over their cross-section, as in most other methods. It is general because it applies to any configuration, any geometry and any refractive index of the guides, provided their fields can be calculated.

High-temperature series analyses of the classical Heisenberg and XY models

Although there is now a good measure of agreement between Monte Carlo and high-temperature series expansion estimates for Ising ( n = 1) models, published results for the critical temperature from series expansions up to 12th order for the three-dimensional classical Heisenberg ( n = 3) and XY ( n = 2) models do not agree very well with recent high-precision Monte Carlo estimates. In order to clarify this discrepancy we have analyzed extended high-temperature series expansions of the susceptibility, the second correlation moment, and the second field derivative of the susceptibility, which have been derived a few years ago by Lüscher and Weisz for general O( n) vector spin models on D-dimensional hypercubic lattices up to 14th order in K ≡ J/ k B T. By analyzing these series expansions in three dimensions with two different methods that allow for confluent correction terms, we obtain good agreement with the standard field theory exponent estimates and with the critical temperatures estimates from the new high-precision Monte Carlo simulations. Furthermore, for the Heisenberg model we also reanalyze existing series for the susceptibility on the BCC lattice up to 11th order and on the FCC lattice up to 12th order using the same methods.

Crash behaviour of circular tubes with large side openings

In this paper the finite element method (FEM) is used to investigate the response of a thin circular tube with a large, non-axisymmetric opening with circular ends in the axial direction to applied axial compression, longitudinal end twist and bending loads. Bending is applied to the shell end in an arbitrary longitudinal plane that passes through the shell axis. The results obtained from the computer simulation are compared with those experimentally determined values that are available in the literature and there appears to be a good measure of agreement. In addition, the computer-based study is extended beyond the experimental range and into the material plastic response regime. This embraces the plastic collapse mode of the structure which culminates in the formation of concertina or lobar wrinkles. Changes in the structural stiffness of the system as defined by the load-deflection curve are reported. We have found a close agreement between the values computed using the FEM and the limited number of available experimental results. This is also the case in other studies that we have undertaken and leads us to recommend that the method of investigating the response of such systems should be a combination of computer simulation and a limited number of experiments—which are required for verification purposes only. The method used in this paper is based on the use of commercially available FEM code and post-processing packages.

The Eunuchus: Terence and Menander

A vast amount has been written on the relationship between Terence's and Menander's Eunuchus. On some points a good measure of agreement has been reached, but much remains in dispute. In an important article W. Ludwig convincingly demonstrated the inner unity of Terence's plot, against earlier theories of large-scale ‘contaminatio’ The nature of the changes made by Terence in introducing two characters from Menander's Colax (30–3) is now fairly clear, although argument is possible over details. The changes are numerous but relatively small and do not affect the main lines of Menander's plot. In this paper I shall argue that Terence made similar changes in two other parts of the play, and that these caused certain anomalies which have prompted theories of more drastic Terentian change.

Comparison of the measurements of the cerebral ventricles obtained by CT scanning and pneumoencephalography

This study was undertaken to compare the accuracy of measurements of the venticular system obtained by the CT scanner and pneumoencephalography (PEG). In it the ventricular system was evaluated in each case by measuring the span of the frontal horns, cellae mediae and third ventricle in relation to the diameter of the inner and outer tables of the skull from the PEG films. The indices of Evans, Schiersmann, and Schaltenbrand and Nürnberger were applied to these measurements. The same indices were obtained using the appropriate CT printouts. A very good measure of agreement was obtained with the indices arrived at from both the CT scan printouts and the pneumoencephalograms.

The developmental dynamics of Tipula paludosa and the relation of climate to its growth pattern, flight season and geographical distribution.

The model of Meats (1974a) is tested against Laughlin's (1967a) data on growth in the field. A good measure of agreement is found. The model is then used to investigate the consequences of the univoltine T. paludosa starting its life cycle (flight season) at various dates in the range quoted by Coulson (1962)-i.e. from July to October. Similarly the influence of increased or decreased monthly temperatures is also investigated. The model indicates that growth will be poorer the later the life cycle starts or the lower the mean monthly temperature.Populations at Moor House (high Pennines) are probably obliged to start their cycle earlier by shortening the prepupal/pupal period because the relatively colder average temperatures would otherwise prevent the attainment of a suitably sized adult. Lowland populations from Canada, England, Germany and Poland differ in developmental schedule depending on prevailing temperatures but usually achieve sufficient growth despite a relatively prolonged prepupal/pupal period and late flight season. Dry conditions (which, like low temperatures, can slow growth) are not associated with advanced flight seasons. In areas where low temperatures are critical, successful growth may be restricted to wet soils. The relation of climate to prepupal diapause is discussed and developmental dynamics is related to potential geographical range.

Grid Framework Method for Thick Plates in Flexure

The idealization of flat plates under flexure into equivalent grid frameworks of beams or shafts, or both, has developed since the original method was proposed. In this note, an improved version of Yettram and Hussain's model is established for a square configuration, so that possible linear variation of bending moment and the associated shearing force can be taken into account. As a consequence, a more realistic modeling can be made for thick plates where shear deformation is significant. Problems are presented which show a good measure of agreement with those from the finite element method of Pryor, et al., over a wide range of thicknesses.

On the connection between cold fronts and gust bumps

This article shows in a statistical and numerical way that there is a relationship between moving cold fronts over the southern part of the North Sea and “gust bumps” — defined as pronounced sudden rises in the sea level — on the Dutch coast. The speed of the front is a crucial parameter in the occurrence of a gust bump, there being every indication that it must be between 29 and 36 kts. The conclusion can be drawn that resonance is present due to the coincidence of frontal speed and the speed of long waves in shallow waters. When the gust bump of 13 December 1956 was represented in a numerical model of the North Sea, there was a reasonable to good measure of agreement between the computed and observed deviations of the water level.

Energy levels of 56Fe: The 56Fe(n, n′γ) 56Fe reaction and the γ-spectrum of 56Co

Relative intensities for the production of γ-rays by inelastic neutron scattering from iron have been measured at 90° with 4.3 MeV and 5.3 MeV neutrons. The gamma radiations following the decay of 56Co to 56Fe have also been measured. In each case, the γ-rays were detected with a Ge(Li) spectrometer of about 30 cm 3 in volume. On the basis of these two measurements, a decay scheme was constructed which has a good measure of agreement with the level positions and spins obtained by McGrory in a shell-model calculation of the energy levels of 56Fe.

K − mesic X-rays from light nuclei

The K − mesic X-ray yields from 7Li, 9Be, B and 12C have recently been measured. Here we analyse these data in terms of the competing Auger, X-ray and nuclear absorption rates. We show that the simple model involving decay solely by circular orbits does not agree with the experimental data but a good measure of agreement can be obtained by neglecting Auger transitions and assuming that only a proportion of the mesons decay by circular orbits. Unfortunately these postulates are not unique in giving agreement with the experimental results.

Nuclear-Matter Radii from a Reformulated Optical Model

A reformulation of the optical model is developed in which the real parts of the potential are obtained from nuclear-matter distributions and the nucleon-nucleon force. The model is applied to proton elastic scattering data at 14.5, 30.3, and 40.0 MeV and succeeds in fitting the data as well as, or better than, the standard optical model despite the fact that two fewer parameters are needed in the new model. Values, accurate to a few percent, are obtained for the nuclear rms matter radii which are independent of the incident proton energy. These values are greater than the corresponding rms proton radii obtained from electron scattering and muonic x-ray work, and indicate that nuclear neutron rms radii are greater than nuclear proton rms radii by about 0.6 F. Information is also obtained concerning the spin-isospin-independent part of the nucleon-nucleon force, indicating a mean-square radius of 2.25\ifmmode\pm\else\textpm\fi{}0.6 ${\mathrm{F}}^{2}$ and a volume integral of 400\ifmmode\pm\else\textpm\fi{}20 MeV ${\mathrm{F}}^{3}$. The neutron and proton density distributions found from this work and muonic studies are used to calculate the imaginary potential, and this is compared with the phenomenological form found in the analyses performed with the new model. The good measure of agreement between the two potentials indicates that the model can be extended to include this term in a more logical manner, and with fewer parameters, than in the standard formulation of the optical model. The model is readily extended, in appropriate cases, for use with complex particles.

Elastic stresses in torispherical drumheads: Experimental verification

Four steel torsispherical drumheads, machined from oversized blanks and welded to drums of approximately equal thickness, have been tested under internal pressure within the elastic range. The resulting stress distributions are compared with results obtained from photoelastic analyses of geometrically similar models and with two independent computed solutions for each of the four shapes. Important differences are found between prototype and photoelastic results for the two thin shallow heads. Otherwise there is a good measure of agreement between the different stress distributions for each head.

Fission fragment damage to crystal lattices: track contrast

In previous papers (Bowden & Chadderton 1962; Chadderton & Montagu-Pollock 1963) some account has been given of the type of damage sustained by both stable and unstable crystals, and its relation to the principle mechanisms of energy loss. In particular it has been demonstrated that fission fragments can create so much damage that ‘tracks’ may be observed in the electron microscope, and that these may be black or white, depending upon the thickness of the bombarded crystal. This paper considers the nature of black tracks and describes their formation as images in the electron microscope in terms of ‘diffraction contrast’. A model is established for the damage produced by a fission fragment in an initially perfect crystal. This essentially consists of a central cylinder of disturbed material sur­rounded by a radial strain field, and is mathematically very similar to the model invoked by Ashby & Brown (1963 a ) to describe the spherically symmetrical coherency strain. The model is used in conjunction with the two-beam dynamical theory of electron diffraction (Howie & Whelan 1961) and machine calculations are made of contrast profiles for tracks at different positions in the crystal and for various values of the parameters involved. A good measure of agreement between experiment and theory is demonstrated, and, in particular, it is shown how anomalous images and oscillatory contrast effects may be explained. Asymmetric images on dark-field micrographs can be used in a determination of the direction of radial strain, and anomalous images in both bright and dark field yield information about the direction of particle travel. A method is suggested for obtaining information concerning the pattern of damage in continuous and discontinuous tracks and for testing the validity of the depleted zone concept.