Measurement error caused by spatial misalignment in environmental epidemiology

Copyright @ 2009 Gryparis et al - Published by Oxford University Press.In many environmental epidemiology studies, the locations and/or times of exposure measurements and health assessments do not match. In such settings, health effects analyses often use the predictions from an exposure model as a covariate in a regression model. Such exposure predictions contain some measurement error as the predicted values do not equal the true exposures. We provide a framework for spatial measurement error modeling, showing that smoothing induces a Berkson-type measurement error with nondiagonal error structure. From this viewpoint, we review the existing approaches to estimation in a linear regression health model, including direct use of the spatial predictions and exposure simulation, and explore some modified approaches, including Bayesian models and out-of-sample regression calibration, motivated by measurement error principles. We then extend this work to the generalized linear model framework for health outcomes. Based on analytical considerations and simulation results, we compare the performance of all these approaches under several spatial models for exposure. Our comparisons underscore several important points. First, exposure simulation can perform very poorly under certain realistic scenarios. Second, the relative performance of the different methods depends on the nature of the underlying exposure surface. Third, traditional measurement error concepts can help to explain the relative practical performance of the different methods. We apply the methods to data on the association between levels of particulate matter and birth weight in the greater Boston area.This research was supported by NIEHS grants ES012044 (AG, BAC), ES009825 (JS, BAC), ES007142 (CJP), and ES000002 (CJP), and EPA grant R-832416 (JS, BAC)

The APHEKOM Project: A literature review of air pollution interventions and their impact of public health

Intervention studies play an important role in supporting and complementing scientific validation of results of epidemiological non-intervention studies linking air pollution and health. In this paper a collection of existing published intervention studies is reviewed with the aim to give a summarized overview spanning a variety of approaches regarding the type of the intervention and findings with the main focus on studies that assessed interventions that improved air quality and the associated positive impact on public health. Air pollution interventions were defined as events aimed at reducing air pollution and also events where air pollution reductions occurred as a side effect

The effects of socioeconomic status and indices of physical environment on reduced birth weight and preterm births in Eastern Massachusetts

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Air pollution and social characteristics have been shown to affect indicators of health. While use of spatial methods to estimate exposure to air pollution has increased the power to detect effects, questions have been raised about potential for confounding by social factors.Methods: A study of singleton births in Eastern Massachusetts was conducted between 1996 and 2002 to examine the association between indicators of traffic, land use, individual and area-based socioeconomic measures (SEM), and birth outcomes ( birth weight, small for gestational age and preterm births), in a two-level hierarchical model.Results: We found effects of both individual ( education, race, prenatal care index) and area-based ( median household income) SEM with all birth outcomes. The associations for traffic and land use variables were mainly seen with birth weight, with an exception for an effect of cumulative traffic density on small for gestational age. Race/ethnicity of mother was an important predictor of birth outcomes and a strong confounder for both area-based SEM and indices of physical environment. The effects of traffic and land use differed by level of education and median household income.Conclusion: Overall, the findings of the study suggested greater likelihood of reduced birth weight and preterm births among the more socially disadvantaged, and a greater risk of reduced birth weight associated with traffic exposures. Results revealed the importance of controlling simultaneously for SEM and environmental exposures as the way to better understand determinants of health.This work is supported by the Harvard Environmental Protection Agency (EPA) Center, Grants R827353 and R-832416, and National Institute for Environmental Health Science (NIEHS) ES-0002

The association of cold weather and all-cause and cause-specific mortality in the island of Ireland between 1984 and 2007

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background This study aimed to assess the relationship between cold temperature and daily mortality in the Republic of Ireland (ROI) and Northern Ireland (NI), and to explore any differences in the population responses between the two jurisdictions. Methods A time-stratified case-crossover approach was used to examine this relationship in two adult national populations, between 1984 and 2007. Daily mortality risk was examined in association with exposure to daily maximum temperatures on the same day and up to 6 weeks preceding death, during the winter (December-February) and cold period (October-March), using distributed lag models. Model stratification by age and gender assessed for modification of the cold weather-mortality relationship. Results In the ROI, the impact of cold weather in winter persisted up to 35 days, with a cumulative mortality increase for all-causes of 6.4% (95%CI=4.8%-7.9%) in relation to every 1oC drop in daily maximum temperature, similar increases for cardiovascular disease (CVD) and stroke, and twice as much for respiratory causes. In NI, these associations were less pronounced for CVD causes, and overall extended up to 28 days. Effects of cold weather on mortality increased with age in both jurisdictions, and some suggestive gender differences were observed. Conclusions The study findings indicated strong cold weather-mortality associations in the island of Ireland; these effects were less persistent, and for CVD mortality, smaller in NI than in the ROI. Together with suggestive differences in associations by age and gender between the two Irish jurisdictions, the findings suggest potential contribution of underlying societal differences, and require further exploration. The evidence provided here will hope to contribute to the current efforts to modify fuel policy and reduce winter mortality in Ireland

Matematikklærerstudenters utvelgelse og bruk av ressurser til matematikkundervisning

Denne studien undersøker åtte femte-års matematikklærerstudenters utvelgelses- og brukspraksis av ressurser tilknyttet forberedelse til, samt i praksis i matematikk. Forskningen forsøker å dekke hull innen tidligere forskning, gjennom å undersøke matematikklærerstudenters ressursbruk, der to teoretiske rammeverkene «Dokument tilnærming til didaktikk» og Adlers konseptualisering av «Ressursbegrepet» brukes for å analysere, gi mening til og forstå funnene. Ressurskart fra DAD er det mest fremtredende aspektet fra gjeldende rammeverk som blir brukt i denne masteroppgaven, og har vært et viktig hjelpemiddel i dette forskningsarbeidet. Forskningen inntar perspektivet til det fortolkende paradigmet og er en kvalitativ psykologisk fenomenologisk studie, der målet er å få tak på matematikklærerstudentenes tanker, refleksjoner og meninger tilknyttet ressursbruk. Datamaterialet ble innhentet gjennom semistrukturerte en-til-en intervju med intervjuobjekter fra tre ulike kohorter: grunnskolelærerutdanning 1.-7., grunnskolelærerutdanning 5.-10, og lektorutdanningen 8.-13. Resultatene fra studien viser at matematikklærerstudentene er bevisste i sin bruk av et bredt omfang av ressurser til forberedelse til og i praksis. Grunnlaget for utvelgelse av ressurser består av seks hovedkriterier og fire tilnærminger til ressursutvelgelse og praksis, deriblant kriteriene variasjon, tilgang og affekt, og tanken om å bruke flere typer ressurser og konkreter i undervisningssammenheng. Matematikklærerstudentenes ressursbruk er preget av en tanke om å supplere ressursene med andre ressurser og varierer basert på formålet med bruk av ressursene. Matematikklærerstudentene påpeker at ressursene må være tilgengelige for bruk, samt skape rom for å oppdage og utvikle kompetanse innenfor matematikkfaget, i tillegg viser matematikklærerstudentene til gjenbruk av ressurser. Blant ressursene som brukes mest er lærebøker med tilhørende digitale ressurser, erfaring og konkreter. Matematikklærerstudentene opplever å være fornøyde med ressursene som er tilgengelige, men ønsker seg likevel en ressursbank og en form for YouTube som kun inneholder videoer med innhold tilpasset matematikkundervisning. Ressursen og fenomenet YouTube er et eget fokusområde i dette forskningsarbeidet. Utvelgelse av YouTube videoer lener seg på matematikklærerstudentenes egne subjektive vurdering, der fire kriterier: språk, relevant innhold, lengde, samt visualiseringer og representasjoner, ligger til grunn. YouTube egner seg til variasjon i undervisningssammenheng og er en ressurs som kan gjenbrukes (dvs. brukes på andre og nye måter), i tillegg påpekes det at YouTube videoer egner seg godt til oppfriskning av matematikklærerstudentenes egen kunnskap. Implikasjoner av denne studien er at viktig informasjon om matematikklærerstudenters ressursbruk er innhentet. Matematikklærerstudenter kan finne støtte i denne informasjonen, og lærerutdannere kan bruke informasjonen for å tilpasse og utvikle lærerutdanningen. Funnene fra denne studien kan altså bidra med informasjon som er med på å skape forståelse for fenomenet ressursbruk blant matematikklærerstudenter.This study examines the selection and use of resources by eight fifth-year pre-service mathematics teachers in preparation for, and in practice of mathematics. The research attempts to fill gaps in previous research by examining pre-service mathematics teachers resource use, using two theoretical frameworks, the "Document Approach to Didactics" and Adlers conceptualization of the notion “Resources”, to analyze, give meaning to, and understand the findings. Resource maps from DAD are the most prominent aspect of the current framework used in this master's thesis and have been an important tool in this research work. The research adopts the perspective of the interpretive paradigm and is a qualitative psychological phenomenological study, where the goal is to obtain the thoughts, reflections, and opinions of pre-service mathematics teachers related to resource use. The data material was obtained through semi-structured one-on-one interviews with participants from three different cohorts: primary school teacher education 1.-7., primary school teacher education 5.-10., and associate professor education 8.-13. The results of the study show that the pre-service mathematics teachers are deliberate in their use of a wide range of resources for preparation for and in practice. The basis for selecting resources consists of six main criteria and four approaches to resource selection and practice, including the criteria of variety, access and affect, and the idea of using multiple types of resources and concretes in a teaching context. The pre-service mathematics teachers` resource use is characterized by thinking of the resources as supplementary each other and varies based on the purpose of using the resources. The pre-service mathematics teachers point out that the resources must be available for use as well as create space for discovering and developing competence within the subject of mathematics, and the pre-service mathematics teachers also indicate that they re-source. Among the resources that are used most are textbooks with associated digital resources, experience and mathematical manipulatives. The pre-service mathematics teachers experience being satisfied with the resources that are available, but still want a resource bank and a form of YouTube that only contains videos with content adapted for mathematics education. The resource and the phenomenon of YouTube is a separate focus area in this research work. The selection of YouTube videos relies on the pre-service mathematics teachers own subjective assessment, which is based on four criteria: language, relevant context, length, as well as visualizations and representations. YouTube is suited for varying in teaching contexts and is a resource that can be re-sourced (i.e. used in different and new ways), additionally YouTube videos are well suited for refreshing the pre-service mathematics teachers own knowledge. Implications of this study are that important information about student mathematics teacher resource use has been obtained. Pre-service mathematics teachers can find support in this information, and teacher educators can use the information to adapt and develop teacher education. The findings from this study can therefore contribute information that helps to create an understanding of the phenomenon of resource use among pre-service mathematics teachers

'TaxTrack': Introducing a Democratic Innovation for Taxation

In this article we introduce an input-oriented democratic innovation – that we term ‘TaxTrack’ – which offers individual taxpayers the means to engage with their political economies in three ways. After joining the TaxTrack program, an individual can: (1) see and understand how much, and what types, of taxes they have contributed, (2) see and understand how their tax contributions are, or have been, used, and (3) control what their tax contributions can, or cannot, be spent on. We explain this democratic innovation in two ways. The first is through evocation to prefigure what the innovation could look like in future practise which raises the prospects for both good and problematic outcomes. The second is through formal theory to produce a detailed model of the innovation to assist theory building. We conclude by discussing three interactive outcomes of ‘TaxTrack’ through the democratic innovations literature to establish the beginnings of a theory for the model. This theory tells us that ‘TaxTrack’ can return benefits to its users and the democratic regimes in which they are located but it may also place restrictions on output-oriented innovations like Participatory Budgeting

Über eine Klasse polynomialer Scharen selbstadjungierter Operatoren im Hilbertraum

HEK293A cells expressing either mouse MOG (mMOG) or rat MOG (rMOG) C terminally tagged with EGFP. (DOCX 2792 kb

Determination of Heavy Metals Present in the Hypoglycemic Karela Powder: An Analytical Assay

Open Access journalDiabetes is a common health condition associated with heightened glucose content in the blood due to impaired insulin production/function. Considering current societal trends, the number of patients with this condition is growing fast. To help this subset of the population, researchers are investigating natural products exhibiting hypoglycaemic effects. It is well known that one third of patients with diabetes mellitus use some form of complementary or alternative medicine. One plant that has received some attention for its anti-diabetic properties is bitter melon, or Momordica charantia, commonly referred to as bitter gourd, karela and balsam pear

Efficiency of two-phase methods with focus on a planned population-based case-control study on air pollution and stroke

<p>Abstract</p> <p>Background</p> <p>We plan to conduct a case-control study to investigate whether exposure to nitrogen dioxide (NO₂) increases the risk of stroke. In case-control studies, selective participation can lead to bias and loss of efficiency. A two-phase design can reduce bias and improve efficiency by combining information on the non-participating subjects with information from the participating subjects. In our planned study, we will have access to individual disease status and data on NO₂exposure on group (area) level for a large population sample of Scania, southern Sweden. A smaller sub-sample will be selected to the second phase for individual-level assessment on exposure and covariables. In this paper, we simulate a case-control study based on our planned study. We develop a two-phase method for this study and compare the performance of our method with the performance of other two-phase methods.</p> <p>Methods</p> <p>A two-phase case-control study was simulated with a varying number of first- and second-phase subjects. Estimation methods: <it>Method 1</it>: Effect estimation with second-phase data only. <it>Method 2</it>: Effect estimation by adjusting the first-phase estimate with the difference between the adjusted and unadjusted second-phase estimate. The first-phase estimate is based on individual disease status and residential address for all study subjects that are linked to register data on NO₂-exposure for each geographical area. <it>Method 3</it>: Effect estimation by using the expectation-maximization (EM) algorithm without taking area-level register data on exposure into account. <it>Method 4</it>: Effect estimation by using the EM algorithm and incorporating group-level register data on NO₂-exposure.</p> <p>Results</p> <p>The simulated scenarios were such that, unbiased or marginally biased (< 7%) odds ratio (OR) estimates were obtained with all methods. The efficiencies of method 4, are generally higher than those of methods 1 and 2. The standard errors in method 4 decreased further when the case/control ratio is above one in the second phase. For all methods, the standard errors do not become substantially reduced when the number of first-phase controls is increased.</p> <p>Conclusion</p> <p>In the setting described here, method 4 had the best performance in order to improve efficiency, while adjusting for varying participation rates across areas.</p

Global short-term mortality risk and burden associated with tropical cyclones from 1980 to 2019: a multi-country time-series study

Background The global spatiotemporal pattern of mortality risk and burden attributable to tropical cyclones is unclear. We aimed to evaluate the global short-term mortality risk and burden associated with tropical cyclones from 1980 to 2019.Methods The wind speed associated with cyclones from 1980 to 2019 was estimated globally through a parametric wind field model at a grid resolution of 0 & BULL;5 & DEG;x 0 & BULL;5 & DEG;. A total of 341 locations with daily mortality and temperature data from 14 countries that experienced at least one tropical cyclone day (a day with maximum sustained wind speed associated with cyclones & GE;17 & BULL;5 m/s) during the study period were included. A conditional quasi-Poisson regression with distributed lag non-linear model was applied to assess the tropical cyclone-mortality association. A meta-regression model was fitted to evaluate potential contributing factors and estimate grid cell-specific tropical cyclone effects.Findings Tropical cyclone exposure was associated with an overall 6% (95% CI 4-8) increase in mortality in the first 2 weeks following exposure. Globally, an estimate of 97 430 excess deaths (95% empirical CI [eCI] 71 651-126 438) per decade were observed over the 2 weeks following exposure to tropical cyclones, accounting for 20 & BULL;7 (95% eCI 15 & BULL;2-26 & BULL;9) excess deaths per 100 000 residents (excess death rate) and 3 & BULL;3 (95% eCI 2 & BULL;4-4 & BULL;3) excess deaths per 1000 deaths (excess death ratio) over 1980-2019. The mortality burden exhibited substantial temporal and spatial variation. East Asia and south Asia had the highest number of excess deaths during 1980-2019: 28 744 (95% eCI 16 863-42 188) and 27 267 (21 157-34 058) excess deaths per decade, respectively. In contrast, the regions with the highest excess death ratios and rates were southeast Asia and Latin America and the Caribbean. From 1980-99 to 2000-19, marked increases in tropical cyclone-related excess death numbers were observed globally, especially for Latin America and the Caribbean and south Asia. Grid cell-level and country-level results revealed further heterogeneous spatiotemporal patterns such as the high and increasing tropical cyclone-related mortality burden in Caribbean countries or regions. Interpretation Globally, short-term exposure to tropical cyclones was associated with a significant mortality burden, with highly heterogeneous spatiotemporal patterns. In-depth exploration of tropical cyclone epidemiology for those countries and regions estimated to have the highest and increasing tropical cyclone-related mortality burdens is urgently needed to help inform the development of targeted actions against the increasing adverse health impacts of tropical cyclones under a changing climate.Australian Research Council and Australian National Health and Medical Research Council