South Africa - CGIAR Partnership Results in New Maize Varieties with 30 to 50 percent higher yields

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Parameter values used in model. Parameters used in the sensitivity analysis were drawn from uniform distributions with the plausible ranges indicated.

<p>Parameter values used in model. Parameters used in the sensitivity analysis were drawn from uniform distributions with the plausible ranges indicated.</p

Model calibration to cumulative and annual pertussis incidence in the 1993–2004 vaccine era.

<p>Cases confirmed by the Public Health Laboratory —Toronto and the Hospital for Sick Children are shown in black and model predicted incidence of detected cases for the four age groups (under 2 months old, 2–4 months old, 4–6 months old, 6–24 months old) is shown in grey.</p

Estimated pertussis vaccine coverage at 7 years of age.

<p>^a McWha L, MacArthur A, Badiani T, Schouten H, Tam T, et al. (2004) Measuring up: results from the National Immunization Coverage Survey, 2002. Can Commun Dis Rep 30: 37–50.</p

Estimated under-report of pertussis by age group.

<p>The model predicted ratio of underlying pertussis cases per laboratory-confirmed case was calculated based on reported cases for the Greater Toronto Area between 1993 and 2004. Results are presented on a logarithmic scale. For each age group, the minimum, mean, and maximum number of model predicted undetected cases for every reported case are displayed.</p

Model calibration to pertussis incidence in the pre-vaccine era.

<p>Model-projected (a) cumulative pertussis incidence and (b) annual pertussis incidence in the population under 2 years old (bars) were fit to a time-series of pertussis incidence between 1880 and 1929 (line). Best-fit parameter estimates were: <i>β₁</i> of 11.335, <i>β₂</i> of 0.050, and <i>β</i>₃ or 0.029 assuming duration of immunity following infection of approximately 18 years.</p

Multi-way sensitivity analysis.

<p>Probability of reported diagnosis for each age group. Confidence limits are based on the mean and standard deviation of the results from the sensitivity analysis.</p

Model overview.

<p>The population was divided into eight different disease states: susceptible (S), vaccinated (V), exposed (E, infected but not infectious), infectious (I), recovered (R), re-susceptible (S_R), re-exposed (E_R), and re-infectious (I_R). Each vaccination compartment (V₁…V₅) represents a different level of conferred immunity as children progress through the 5 recommended childhood pertussis vaccines. For complete model details refer to <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083850#pone.0083850.s001" target="_blank">File S1</a></b>.</p

Historical Epidemiology of the Second Cholera Pandemic: Relevance to Present Day Disease Dynamics

<div><p>Despite nearly two centuries of study, the fundamental transmission dynamic properties of cholera remain incompletely characterized. We used historical time-series data on the spread of cholera in twelve European and North American cities during the second cholera pandemic, as reported in Amariah Brigham’s 1832 <i>A Treatise on Epidemic Cholera</i>, to parameterize simple mathematical models of cholera transmission. Richards growth models were used to derive estimates of the basic reproductive number (R₀) (median: 16.0, range: 1.9 to 550.9) and the proportion of unrecognized cases (mean: 96.3%, SD: 0.04%). Heterogeneity in model-generated R₀ estimates was consistent with variability in cholera dynamics described by contemporary investigators and may represent differences in the nature of cholera spread. While subject to limitations associated with measurement and the absence of microbiological diagnosis, historical epidemic data are a potentially rich source for understanding pathogen dynamics in the absence of control measures, particularly when used in conjunction with simple and readily interpretable mathematical models.</p></div

Undiscounted health and economic outcomes associated with different syphilis screening strategies.

<p>Abbreviations: QALY, quality-adjusted life year; ICER, incremental cost-effectiveness ratio.</p>a<p>Higher coverage, 100% coverage; Usual, 57% coverage.</p