124 research outputs found

    The Use of Picture Books in the High School Classroom: A Qualitative Case Study

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    Picture books (stories in which the both the text and illustrations contribute to meaning) have long been thought of as appropriate only at primary grade levels because of their short length, simple plots, and minimal number of characters. When used at the secondary level, their principal function has been as remediation for struggling readers or English language learners (ELLs). However, anecdotal evidence and an exhaustive literature review strongly suggest that the supplemental use of picture books increases engagement and learning among high school students at all instructional levels. The purpose of this study was to analyze the effects of picture books on high school students’ engagement with these texts

    Does origin always matter? Evaluating the influence of nonlocal seed provenances for ecological restoration purposes in a widespread and outcrossing plant species

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    For restoration purposes, nature conservation generally enforces the use of local seed material based on the “local-is-best” (LIB) approach. However, in some cases recommendations to refrain from this approach have been made. Here we test if a common widespread species with no obvious signs of local adaptation may be a candidate species for abandoning LIB during restoration. Using 10 microsatellite markers we compared population genetic patterns of the generalist species Daucus carota in indigenous and formerly restored sites (nonlocal seed provenances). Gene diversity overall ranged between He = 0.67 and 0.86 and showed no significant differences between the two groups. Hierarchical AMOVA and principal component analysis revealed very high genetic population admixture and negligible differentiation between indigenous and restored sites (FCT = 0.002). Moreover, differentiation between groups was caused by only one outlier population, where inbreeding effects are presumed. We therefore conclude that the introduction of nonlocal seed provenances in the course of landscape restoration did not jeopardize regional species persistence by contributing to inbreeding or outbreeding depressions, or any measurable adverse population genetic effect. On the basis of these results, we see no obvious objections to the current practice to use the 10-fold cheaper, nonlocal seed material of D. carota for restoration projects

    Model-informed target product profiles of long-acting-injectables for use as seasonal malaria prevention

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    Seasonal malaria chemoprevention (SMC) has proven highly efficacious in reducing malaria incidence. However, the continued success of SMC is threatened by the spread of resistance against one of its main preventive ingredients, Sulfadoxine-Pyrimethamine (SP), operational challenges in delivery, and incomplete adherence to the regimens. Via a simulation study with an individual-based model of malaria dynamics, we provide quantitative evidence to assess long-acting injectables (LAIs) as potential alternatives to SMC. We explored the predicted impact of a range of novel preventive LAIs as a seasonal prevention tool in children aged three months to five years old during late-stage clinical trials and at implementation. LAIs were co-administered with a blood-stage clearing drug once at the beginning of the transmission season. We found the establishment of non-inferiority of LAIs to standard 3 or 4 rounds of SMC with SP-amodiaquine was challenging in clinical trial stages due to high intervention deployment coverage. However, our analysis of implementation settings where the achievable SMC coverage was much lower, show LAIs with fewer visits per season are potential suitable replacements to SMC. Suitability as a replacement with higher impact is possible if the duration of protection of LAIs covered the duration of the transmission season. Furthermore, optimising LAIs coverage and protective efficacy half-life via simulation analysis in settings with an SMC coverage of 60% revealed important trade-offs between protective efficacy decay and deployment coverage. Our analysis additionally highlights that for seasonal deployment for LAIs, it will be necessary to investigate the protective efficacy decay as early as possible during clinical development to ensure a well-informed candidate selection process

    Modelling reactive case detection strategies for interrupting transmission of Plasmodium falciparum malaria

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    As areas move closer to malaria elimination, a combination of limited resources and increasing heterogeneity in case distribution and transmission favour a shift to targeted reactive interventions. Reactive case detection (RCD), the following up of additional individuals surrounding an index case, has the potential to target transmission pockets and identify asymptomatic cases in them. Current RCD implementation strategies vary, and it is unclear which are most effective in achieving elimination.; OpenMalaria, an established individual-based stochastic model, was used to simulate RCD in a Zambia-like setting. The capacity to follow up index cases, the search radius, the initial transmission and the case management coverage were varied. Suitable settings were identified and probabilities of elimination and time to elimination estimated. The value of routinely collected prevalence and incidence data for predicting the success of RCD was assessed.; The results indicate that RCD with the aim of transmission interruption is only appropriate in settings where initial transmission is very low (annual entomological inoculation rate (EIR) 1-2 or prevalence approx

    Emulator-based Bayesian optimization for efficient multi-objective calibration of an individual-based model of malaria

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    Individual-based models have become important tools in the global battle against infectious diseases, yet model complexity can make calibration to biological and epidemiological data challenging. We propose using a Bayesian optimization framework employing Gaussian process or machine learning emulator functions to calibrate a complex malaria transmission simulator. We demonstrate our approach by optimizing over a high-dimensional parameter space with respect to a portfolio of multiple fitting objectives built from datasets capturing the natural history of malaria transmission and disease progression. Our approach quickly outperforms previous calibrations, yielding an improved final goodness of fit. Per-objective parameter importance and sensitivity diagnostics provided by our approach offer epidemiological insights and enhance trust in predictions through greater interpretability

    Theory of reactive interventions in the elimination and control of malaria

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    Reactive case detection (RCD) is an integral part of many malaria control and elimination programmes and can be conceived of as a way of gradually decreasing transmission. However, it is unclear under what circumstances RCD may have a substantial impact on prevalence, how likely it is to lead to local elimination, or how effective it needs to be to prevent reintroduction after transmission has been interrupted.; Analyses and simulations of a discrete time compartmental susceptible-infectious-susceptible (SIS) model were used to understand the mechanisms of how RCD changes transmission dynamics and estimate the impact of RCD programmes in a range of settings with varying patterns of transmission potential and programme characteristics. Prevalence survey data from recent studies in Zambia were used to capture the effects of spatial clustering of patent infections.; RCD proved most effective at low prevalence. Increasing the number of index cases followed was more important than increasing the number of neighbours tested per index case. Elimination was achieved only in simulations of situations with very low transmission intensity and following many index cases. However, RCD appears to be helpful in maintaining the disease-free state after achieving malaria elimination (through other interventions).; RCD alone can eliminate malaria in only a very limited range of settings, where transmission potential is very low, and improving the coverage of RCD has little effect on this range. In other settings, it is likely to reduce disease burden. RCD may also help maintain the disease-free state in the face of imported infections. Prevalence survey data can be used to estimate a targeting ratio (the ratio of prevalence found through RCD to that in the general population) which is an important determinant of the effect of RCD

    The Transferability of Lipid-Associated Loci Across African, Asian and European Cohorts

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    Abstract: Most genome-wide association studies are based on samples of European descent. We assess whether the genetic determinants of blood lipids, a major cardiovascular risk factor, are shared across populations. Genetic correlations for lipids between European-ancestry and Asian cohorts are not significantly different from 1. A genetic risk score based on LDL-cholesterol-associated loci has consistent effects on serum levels in samples from the UK, Uganda and Greece (r = 0.23–0.28, p < 1.9 × 10−14). Overall, there is evidence of reproducibility for ~75% of the major lipid loci from European discovery studies, except triglyceride loci in the Ugandan samples (10% of loci). Individual transferable loci are identified using trans-ethnic colocalization. Ten of fourteen loci not transferable to the Ugandan population have pleiotropic associations with BMI in Europeans; none of the transferable loci do. The non-transferable loci might affect lipids by modifying food intake in environments rich in certain nutrients, which suggests a potential role for gene-environment interactions

    Implementing a multisector public-private partnership to improve urban hypertension management in low-and middle- income countries

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    BACKGROUND: Cardiovascular disease presents an increasing health burden to low- and middle-income countries. Although ample therapeutic options and care improvement frameworks exist to address its prime risk factor, hypertension, blood pressure control rates remain poor. We describe the results of an effectiveness study of a multisector urban population health initiative that targets hypertension in a real-world implementation setting in cities across three continents. The initiative followed the "CARDIO4Cities" approach (quality of Care, early Access, policy Reform, Data and digital technology, Intersectoral collaboration, and local Ownership). METHOD: The approach was applied in Ulaanbaatar in Mongolia, Dakar in Senegal, and Sao Paulo in Brazil. In each city, a portfolio of evidence-based practices was implemented, tailored to local priorities and available data. Outcomes were measured by extracting hypertension diagnosis, treatment and control rates from primary health records. Data from 18,997 patients with hypertension in primary health facilities were analyzed. RESULTS: Over one to two years of implementation, blood pressure control rates among enrolled patients receiving medication tripled in Sao Paulo (from 12.3% to 31.2%) and Dakar (from 6.7% to 19.4%) and increased six-fold in Ulaanbaatar (from 3.1% to 19.7%). CONCLUSIONS: This study provides first evidence that a multisectoral population health approach to implement known best-practices, supported by data and digital technologies, and relying on local buy-in and ownership, can improve hypertension control in high-burden urban primary care settings in low-and middle-income countries

    Model development, data, and public health: A combined approach against malaria

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    The health burden of infectious diseases remains substantial. Within ever-changing public health landscapes, characterised by complex disease biologies and limited operational resources, appropriate control strategies are often difficult to identify. In recent years, there has been an explosive increase in the popularity of mathematical modelling to bridge evidence gaps and support (policy) decision-making. To ensure accurate predictions, e.g. on the public health impact of new interventions, models must be grounded in plausible assumptions and calibrated to diverse data on multiple epidemiological and biological relationships. Through a comprehensive investigation of the modelling process from development to application, my research aims to prompt discussions about the role of infectious disease modelling in decision-making and about opportunities for modernisation. With application to malaria modelling, I present methodological advancements, structural analyses and discussions, and application case studies. This includes the development of a novel, machine learning-based calibration approach that outperforms previous methods. A generalisable framework for incorporating calibration data while accounting for contextual covariates is developed and applied to a database of PfPR-incidence records. I subsequently discuss the link between model calibration decisions and the model's later uses in simulating epidemiological relationships. Taking the leap from model development to application, I assess the use of surveillance-response interventions for malaria elimination, addressing the various technical challenges of quantifying elimination itself. Finally, I shift perspective towards the potentials and pitfalls of using modelling to support decision-making. The research presented in this thesis contributes to keeping malaria modelling up-to-date with computational methods and global health developments. Many of the principles presented here encompass general discussions of infectious disease modelling, and aim to encourage conversations about the place of modelling at the public health decision-making table
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