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Dive into the research topics where Ana Isabel Miranda is active.

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Featured researches published by Ana Isabel Miranda.


International Journal of Wildland Fire | 2008

Fire activity in Portugal and its relationship to weather and the Canadian Fire Weather Index System

A. Carvalho; Mike D. Flannigan; K. A. Logan; Ana Isabel Miranda; C. Borrego

The relationships among the weather, the Canadian Fire Weather Index (FWI) System components, the monthly area burned, and the number of fire occurrences from 1980 to 2004 were investigated in 11 Portuguese districts that represent respectively 66% and 61% of the total area burned and number of fires in Portugal. A statistical approach was used to estimate the monthly area burned and the monthly number of fires per district, using meteorological variables and FWI System components as predictors. The approach succeeded in explaining from 60.9 to 80.4% of the variance for area burned and between 47.9 and 77.0% of the variance for the number of fires; all regressions were highly significant (P < 0.0001). The monthly mean and the monthly maximum of daily maximum temperatures and the monthly mean and extremes (maximum and 90th percentile) of the daily FWI were selected for all districts, except for Braganca and Porto, in the forward stepwise regression for area burned. For all districts combined, the variance explained was 80.9 and 63.0% for area burned and number of fires, respectively. Our results point to highly significant relationships among forest fires in Portugal and the weather and the Canadian FWI System. The present analysis provides baseline information for predicting the area burned and number of fires under future climate scenarios and the subsequent impacts on air quality.


Environment International | 2008

Procedures for estimation of modelling uncertainty in air quality assessment

C. Borrego; A. Monteiro; J. Ferreira; Ana Isabel Miranda; A.M. Costa; A. Carvalho; M. Lopes

The main objectives of this work focus, firstly, on a review of the current existent methodologies to estimate air quality modelling uncertainty, and, secondly, in the preparation of guidelines for modelling uncertainty estimation, which can be used by local and regional authorities responsible for air quality management. From the application exercise, it was concluded that it is possible to define a subset of statistical parameters able to reproduce the general uncertainties estimation. Concerning the quality indicators defined by EU directives, the results show that the legislated uncertainty estimation measures are ambiguous and inadequate in several aspects, mainly in what concerns the error measures for hourly and daily indicators based on the highest observed concentration. A relative error at the percentile correspondent to the allowed number of exceedances of the limit value was suggested and tested, showing that is a more robust and appropriate parameter for model performance evaluation.


The American Journal of Gastroenterology | 2007

A Comprehensive Approach to Evaluate Nutritional Status in Crohn's Patients in the Era of Biologic Therapy: A Case-Control Study

Catarina Sousa Guerreiro; Marília Cravo; Ana Raimundo Costa; Ana Isabel Miranda; Lourdes Tavares; Paula Moura-Santos; Pedro Marques-Vidal; Carlos Nobre Leitão

OBJECTIVES:Evaluate the nutritional status of patients with inactive or mildly active Crohns disease (CD), and identify possible causes for potential deficiencies.METHODS:A total of 78 CD patients and 80 healthy controls were evaluated in respect of nutritional status, dietary intake, and life styles factors.RESULTS:These 73/78 CD patients were on immunomodulating therapies. Mean body mass index (BMI) was lower in patients as compared to controls (P = 0.006) but 32% of CD patients and 33.8% of controls had a BMI > 25, whereas 8% and 23.8% in each group, respectively, were obese (BMI > 30Kg/m2). Fat free mass was significantly decreased in both genders (P < 0.05) whereas fat mass was decreased only in males (P = 0.01). Energy intake was significantly lower in CD patients (P < 0.0001) and we observed significantly lower adjusted mean daily intakes of carbohydrates, monounsaturated fat, fiber, calcium, and vitamins C, D, E, and K (P < 0.05). 29% of patients had excluded grains from their usual diet, 28% milk, 18% vegetables, and 11% fruits. Milk exclusion resulted in a significantly lower consumption of calcium and vitamin K (P < 0.001) and the exclusion of vegetables was associated to a lower consumption of vitamins C and E (P < 0.05). Physical activity was significantly lower in CD patients (P = 0.01) and this lack of physical activity was inversely correlated with increased fat mass percentage (r = −0.315, P = 0.001).CONCLUSIONS:Results showed that the most prevalent form of malnutrition in CD patients was an excess of body weight, which was concomitant with an inadequate dietary intake, namely micronutrients, clearly related to dietary exclusion of certain foods.


Journal of Toxicology and Environmental Health-part B-critical Reviews | 2014

Integrating health on air quality assessment — review report on health risks of two major european outdoor air pollutants: PM and NO

Solange Costa; Joana Ferreira; Carlos Silveira; Carla Costa; Diogo Lopes; Helder Relvas; C. Borrego; Peter Roebeling; Ana Isabel Miranda; João Paulo Teixeira

Quantifying the impact of air pollution on the public’s health has become an increasingly critical component in policy discussion. Recent data indicate that more than 70% of the world population lives in cities. Several studies reported that current levels of air pollutants in urban areas are associated with adverse health risks, namely, cardiovascular diseases and lung cancer. IARC recently classified outdoor air pollution and related particulate matter (PM) as carcinogenic to humans. Despite the air quality improvements observed over the last few years, there is still continued widespread exceedance within Europe, particularly regarding PM and nitrogen oxides (NOx). The European Air Quality Directive 2008/50/EC requires Member States to design appropriate air quality plans for zones where air quality does not comply with established limit values. However, in most cases, air quality is only quantified using a combination of monitored and modeled data and no health impact assessment is carried out. An integrated approach combining the effects of several emission abatement measures on air quality, impacts on human health, and associated implementation costs enables an effective cost–benefit analysis and an added value to the decision-making process. Hence, this review describes the basic steps and tools for integrating health into air quality assessment (health indicators, exposure-response functions). In addition, consideration is given to two major outdoor pollutants: PM and NO2. A summary of the health metrics used to assess the health impact of PM and NO2 and recent epidemiologic data are also described.


Atmospheric Environment | 2000

Impact of road traffic emissions on air quality of the Lisbon region

C. Borrego; Oxana Tchepel; N. Barros; Ana Isabel Miranda

The main purpose of this paper is to present the study of traffic emissions impact on the Lisbon region air quality. Two approaches of emission data generation with high spatial and temporal resolution are presented and compared. Main roads were processed as line sources and hot on-road emissions were calculated based on daily mean traffic and emission factors distinguished for several road classes and vehicle types. Also, the disaggregation of national CORINAIR inventory has been performed on the basis of statistical information of fuel consumption and population density. The comparison of emission data obtained by these two approaches demonstrates a good agreement for total values, but a significant difference for spatial distribution of the data. To ensure completeness of the data, to improve their spatial resolution and also to analyse the impact of the traffic emissions, a combination of the two approaches was applied to generate the emission data used by a photochemical numerical system to simulate the atmospheric circulation and the air pollution pattern in Lisbon under summer meteorological conditions, having different emission scenarios. It was possible to conclude that an air pollution abatement strategy is urgently needed and it should take into account the strong contribution of road traffic emissions to the Lisbon air pollution levels.


International Journal of Wildland Fire | 2005

Smoke measurements during Gestosa-2002 experimental field fires

Ana Isabel Miranda; J. Ferreira; Joana Valente; Pedro Santos; Jorge Humberto Amorim; C. Borrego

Currently, there is a growing awareness that smoke produced during forest fires can expose individuals and populations to hazardous concentrations of air pollutants. Aiming to contribute to a better understanding of the air pollution phenomenon associated with forest fires, this paper presents and analyses the atmospheric emissions and air quality concentration measurements performed in the 2002 fire experiments at Gestosa, Central Portugal. Two vehicles were equipped with a meteorological station and air quality analysers that were turned on continuously to acquire concentrations of particulate matter, nitrogen oxides and carbon monoxide. Nitrogen and sulfur dioxides were measured using a grid of fixed passive samplers. Also, firefighters and research-team members used passive samplers during the experiments in order to estimate the human exposure to these pollutants. Measurements of volatile organic compound emissions, using Tedlar bags, were carried out. Results were analysed taking into account not only the concentration values but also the variables involved, such as the combustion phase and the meteorology, and identifying possible relationships between them. Despite the small size of the burning plots when compared to wildfires, the measured levels of pollutants were however considerable, indicating the effect of these experiments on the local air quality and stressing the serious levels of air pollution that can be expected during wildfires.


International Journal of Wildland Fire | 2004

An integrated numerical system to estimate air quality effects of forest fires

Ana Isabel Miranda

Forest fires are an important source of various gases and particles emitted into the atmosphere that may affect the air quality on a local and/or larger scale. Currently, there is a growing awareness that smoke from wildland fires exposes individuals and populations to hazardous air pollutants. In order to understand and to simulate forest fire effects on air quality, several issues should be analysed and integrated: fire progression, fire emissions, atmospheric flow, smoke dispersion and chemical reactions. In spite of the available models to simulate smoke dispersion and the existence of some systems already covering the main questions, there still remains a lack of integration concerning fire progression. Photochemical pollution is also not included in these modelling systems. AIRFIRE is a numerical system, developed to estimate the effects of forest fires on air quality, integrating several components of the problem through the inclusion of different modules, namely the mesoscale meteorological model MEMO, the photochemical model MARS, and the Rothermel fire spread model. The system was applied to simulate plume dispersion from a wildfire that occurred in a coastal area, close to Lisbon city, at the end of September 1991. Results, namely the obtained pollutants concentration fields, point to a significant impact on the local air quality. Obtained wind fields and concentration patterns revealed the presence of sea breezes and also the influence of the fire in the atmospheric flow. Estimated carbon monoxide concentration levels were very high, exceeding the recommended hourly limit value of the World Health Organization, and ozone concentration values pointed to photochemical production.


Environmental Pollution | 1994

Forest fire emissions in Portugal: a contribution to global warming?

Ana Isabel Miranda; M. Coutinho; C. Borrego

A forecast of expected evolution of carbon dioxide (CO(2)) emissions in Portugal between 1988 and 2010 is presented. Predictions show that CO(2) emissions will almost double in the next twenty years. The equivalent potential CO(2) emissions from nitrogen oxides (NO(x)) and volatile organic compounds (VOC), for a time horizon of 20 years, is also presented. NO(x) and VOC emissions seem to make a significant contribution to the global warming potential of Portuguese emissions. Estimates of CO(2) emissions due to forest fires have been made, oriented towards the study of the Portuguese contribution to the global warming. If the burned area exceeds 100 000 ha this contribution could reach 7% of the total Portuguese CO(2) emissions. The global warming potential of Portuguese forest emissions were also calculated. The climate change predicted to Portugal could be responsible for an increase in the forest fires and consequently for a greater contribution of its emissions to the total values. It was concluded that it is important to quantify emissions of the greenhouse gases, including the contribution of forest fire emissions, not only in Portugal, but in all the Southern European countries.


International Journal of Environment and Pollution | 2005

Air pollution forecast in Portugal : a demand from the new air quality framework directive

A. Monteiro; M. Lopes; Ana Isabel Miranda; C. Borrego; Robert Vautard

This work aims at developing and validating a numerical air quality operational forecasting system that will be applied over Portugal. The CHIMERE model was chosen for the chemistry-transport simulation using the meteorological parameters supplied by the MM5 mesoscale meteorological model, forced by the AVN/NCEP global forecasts. An experiment of 48-hour real-time forecast simulations was performed, on a daily basis, during the four summer months of 2003. The numerical model system is then evaluated against hourly time series of basic meteorological variables and of ozone and NO2 concentrations, collected in several Portuguese monitoring stations included in meteorological and air quality network. Statistical skill scores are discussed and compared with previous studies. The results point this developed model system as a useful tool that can be used and implemented to anticipate pollution episodes, to local and regional air quality management and for population information purpose.


European Journal of Endocrinology | 2010

Iodine intake in Portuguese pregnant women: results of a countrywide study

Edward Limbert; Susana Prazeres; M São Pedro; Deolinda Madureira; Ana Isabel Miranda; Manuel Ribeiro; J Jácome De Castro; Francisco Carrilho; Maria João Oliveira; Henrique Reguengo; Fatima Borges

BACKGROUND Iodine is the key element for thyroid hormone synthesis, and its deficiency, even moderate, is harmful in pregnancy, when needs are increased, because of its potential deleterious effects on fetal brain development. In Portugal, no recent data on iodine intake exists. The objective of this countrywide study was to analyze iodine status in pregnant Portuguese women in order to propose adequate measures to the health authorities. SUBJECTS AND METHODS Using a fast colorimetric method, urine iodine concentration (UIC) was evaluated in 3631 pregnant women followed in 17 maternity hospitals from hinterland and coastal areas in Continental Portugal and the Portuguese islands of Açores and Madeira. RESULTS Median UIC value was 84.9 μg/l (range 67.6-124.1) in Continental Portugal, 69.5 μg/l in Madeira, and 50.0 μg/l in Açores. The percentage of satisfactory values (>150 μg/l) was 16.8, ranging from 8.8 to 34.1 in the Continent, and being 8.2 in Madeira and 2.3 in Açores. The percentage of values below 50 μg/l was 23.7, ranging from 14.0 to 37.4 in the Continent, 33.7 in Madeira, and 50.0 in Açores. CONCLUSIONS Our results point to an inadequate iodine intake in pregnant women assisted in most Portuguese maternity hospitals. Considering the potential deleterious effects of inadequate iodine supply in pregnancy, iodine supplementation is strongly recommended in this period of life.

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M. Lopes

University of Aveiro

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