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A current challenge in the environmental sciences field is to assess air quality at larger urban areas with high level of spatial resolution and, at the same time, with feasible computational resources time demand. This study provides a sensitivity analysis, focused on the implications of different grid resolutions on air quality results, followed by a performance assessment of the URBan AIR (URBAIR) model, a second-generation Gaussian model, as a tool for air quality management in urban areas. Estarreja area, a city located near an industrial complex, was used as case study, and the most critical air pollutants were investigated: particulate matter (PM10) and nitrogen dioxide (NO2). Three different grid resolutions were tested: 0.1 km, 0.2 km and 0.3 km resolutions. Comparative results revealed that all grids provide similar results regarding the spatial distribution of PM10 and NO2 concentrations, with evident differences in the magnitude of those concentrations and in the required computational time. The source apportionment analysis revealed the great contribution of industrial sources and road transport to NO2 and PM10 concentrations, respectively. The URBAIR model is a useful tool to support decision-makers since it considers the specific characteristics of each city, which make it particularly helpful to assess different origins of air pollution, and so, to select the most effective sectorial measures that should be applied to improve local air quality. [ABSTRACT FROM AUTHOR]

Few field tests have assessed the effects of predator-induced stress on prey fitness, particularly in large carnivore-ungulate systems. Because traditional measures of stress present limitations when applied to free-ranging animals, new strategies and systemic methodologies are needed. Recent studies have shown that stress and anxiety related behaviors can influence the metabolic activity of the gut microbiome in mammal hosts, and these metabolic alterations may aid in identification of stress. In this study, we used NMR-based fecal metabolomic fingerprinting to compare the fecal metabolome, a functional readout of the gut microbiome, of cattle herds grazing in low vs. high wolf-impacted areas within three wolf pack territories. Additionally, we evaluated if other factors (e.g., cattle nutritional state, climate, landscape) besides wolf presence were related to the variation in cattle metabolism. By collecting longitudinal fecal samples from GPS-collared cattle, we found relevant metabolic differences between cattle herds in areas where the probability of wolf pack interaction was higher. Moreover, cattle distance to GPS-collared wolves was the factor most correlated with this difference in cattle metabolism, potentially reflecting the variation in wolf predation risk. We further validated our results through a regression model that reconstructed cattle distances to GPS-collared wolves based on the metabolic difference between cattle herds. Although further research is needed to explore if similar patterns also hold at a finer scale, our results suggests that fecal metabolomic fingerprinting is a promising tool for assessing the physiological responses of prey to predation risk. This novel approach will help improve our knowledge of the consequences of predators beyond the direct effect of predation. [ABSTRACT FROM AUTHOR]

The air quality standards defined by the World Health Organization (WHO), and updated in 2005, continue to be much more exigent than current EU legislation, namely regarding the most critical pollutants over Europe: ozone (O3) and particulate matter (PM10 and PM2.5). This work intends to evaluate the fulfilment of these WHO standards in the present and in the future, including climate change effects. This study will be focused on Portugal, where each year, the O3 and PM10 concentrations exceed the legislated limit values. For this, regional air quality simulations for present and future periods were conducted, with CAMx version 6.0, to investigate the impacts of climate change and anthropogenic emission projections on air quality over Portugal in 2050. The climate and emission projections for 2050 were derived from the Representative Concentrations Pathway 8.5 scenario. Modelling results show that, over Portugal, the WHO standards are already not being fulfilled and will continue to be surpassed in the future. When considering climate change and projected anthropogenic emissions and comparing them to the actual scenario, a reduction in the maximum 8-h daily O3 concentration is expected. For PM, the results indicate serious problems regarding the health impact expected for both long-term and short-term exposure. The annual averages for both PM10 and PM2.5 exceed the AQG over the country. The PM short-term exposure is already very high for current conditions and higher impacts are expected for future scenario, in particular regarding the PM10 values. This air quality degradation is caused by the warmer and dryer conditions and the increase of background concentrations of pollutants expected for the 2050 climate. The results evidence that human health protection will be even more critical in the future, particularly for particulate matter. Furthermore, urgent air quality management strategies need to be designed, with transboundary cooperation and implementation. [ABSTRACT FROM AUTHOR]

Each summer period, ozone concentrations surpass the legislation limits in the north of Portugal, more precisely at the Douro Norte monitoring station. To solve/mitigate this air pollution problem, and respond to the EU requirements, air quality plans were studied and designed. An air quality numerical modelling system was applied, with a source apportionment technique (to the most relevant ozone episodes) to identify the major source regions and the main activity sectors responsible for the ozone values at this site. Modelling results pointed out that the background values contribute with more than 50 % to the ozone concentration measured, followed by transport and residential sectors-the main anthropogenic activities. More regional and transboundary strategies are needed to reduce the background concentrations, besides local actions on road transport and residential combustion at urban regions (e.g., the Porto area). [ABSTRACT FROM AUTHOR]

Five air quality models were applied over Portugal for July 2006 and used as ensemble members. Each model was used, with its original set up in terms of meteorology, parameterizations, boundary conditions and chemical mechanisms, but with the same emission data. The validation of the individual models and the ensemble of ozone (O) and particulate matter (PM) is performed using monitoring data from 22 background sites. The ensemble approach, based on the mean and median of the five models, did not improve significantly the skill scores due to large deviations in each ensemble member. Different bias correction techniques, including a subtraction of the mean bias and a multiplicative ratio adjustment, were implemented and analysed. The obtained datasets were compared against the individual modelled outputs using the bias, the root mean square error (RMSE) and the correlation coefficient. The applied bias correction techniques also improved the skill of the individual models and work equally well over the entire range of observed O and PM values. The obtained results revealed that the best bias correction technique was the ratio adjustment with a 4-day training period, demonstrating significant improvements for both analysed pollutants. The increase in the ensemble skill found comprehends a bias reduction of 88 % for O, and 92 % for PM10, and also a decrease in 23 % for O and 43 % for PM10 in what concerns the RMSE. In addition, a spatial bias correction approach was also examined with successful skills comparing to the uncorrected ensemble for both pollutants. [ABSTRACT FROM AUTHOR]

Despite the increasing concern given to air quality in urban and industrial areas in recent years, particular emphasis on regulation, control, and reduction of air pollutant emissions is still necessary to fully characterize the chain emissions-air quality-exposure-dose-health effects, for specific sources. The Estarreja region was selected as a case study because it has one of the largest chemical industrial complexes in Portugal that has been recently expanded, together with a growing urban area with an interesting location in the Portuguese coastland and crossed by important road traffic and rail national networks. This work presents the first air quality assessment for the region concerning pollutant emissions and meteorological and air quality monitoring data analysis, over the period 2000-2009. This assessment also includes a detailed investigation and characterization of past air pollution episodes for the most problematic pollutants: ozone and PM10. The contribution of different emission sources and meteorological conditions to these episodes is investigated. The stagnant meteorological conditions associated with local emissions, namely industrial activity and road traffic, are the major contributors to the air quality degradation over the study region. A set of measures to improve air quality-regarding ozone and PM10 levels-is proposed as an air quality management strategy for the study region. [ABSTRACT FROM AUTHOR]

Five air quality models were applied over Portugal for July 2006 with an ensemble purpose. These models were used, with their own meteorology, parameterizations, boundary conditions and chemical mechanisms, but with the same emission data. The validation of the individual models and its ensemble for ozone (O) and particulate matter was performed using monitoring data from 22 background stations over Portugal. After removing the bias from each model, different ensemble techniques were applied and compared. Besides the median, several weighted ensemble approaches were tested and intercompared: static (SLR) and dynamic (DLR) multiple linear regressions (using less-square optimization method) and the Bayesian Model Averaging (BMA) methodology. The goal of the comparison is to estimate to what extent the ensemble analysis is an improvement with respect to the single model results. The obtained results revealed that no one of the 4 tested ensembles clearly outperforms the others on the basis of statistical parameters and probabilistic analysis (reliability and resolution properties). Nevertheless, statistical results have shown that the application of the weights slightly improves ensemble performance when compared to those obtained from the median ensemble. The same statistical analysis together with the probabilistic measures demonstrates that the SLR and BMA methods are the best performers amongst the assessed methodologies. [ABSTRACT FROM AUTHOR]

In summer, high levels of ozone (O) are frequently measured at both Galicia and Northern Portugal air quality monitoring stations, even exceeding the limit values imposed by legislation. This work aims to investigate the origin of these high O concentrations by the application of a chemical transport modelling system over the northwestern area of the Iberian Peninsula. The WRF-CHIMERE modelling system was applied with high resolution to simulate the selected air pollution episodes that occurred simultaneously in Galicia and North Portugal and in order to study both the contribution of local emission sources and the influence of transboundary pollution. Emission inputs have been prepared based on the development of the Portuguese and Galician emission inventories. The obtained results for O have been evaluated and validated against observations. Modelling results show possible contribution of the transboundary transport over the border of two neighbour regions/countries, indicating that the O episode starts over the urban and industrialised area of North coast of Portugal, reaching the maximum peaks over this region; at the same time, O levels increased over Galicia region, where lower concentrations, but still high, were observed. These results pointed out that air quality management should not be driven by political boundaries and highlight the importance of joining efforts between neighbouring countries. [ABSTRACT FROM AUTHOR]

Recently, specific air quality problems have been detected in the northern region of Portugal. The nitrogen oxide (NO) annual limit value has been surpassed at several air quality monitoring stations in the northern region, and according to European legislation, air quality plans must be designed and implemented to reduce those levels. The analysis of the air quality data from the stations concerning NO exceedances indicates that traffic is responsible for an increase of more than 40 % compared with the urban background value. Specific measures to reduce NOx emissions have been selected and are related not only mainly to the traffic sector but also to the industrial and residential combustion sectors. The main objective of this study is to investigate the impact of the selected measures on the ambient levels of NO in northern Portugal using a numerical modelling tool-The Air Pollution Model (TAPM). TAPM was applied over the study region using a 120 × 120-km simulation domain and a spatial resolution of 4.8 × 4.8 km. The entire year of 2010 was simulated and was set as the base year to analyse the impact of the selected measures. Two scenarios have been defined and simulated: the base situation, which considers current NOx emissions, and the reduction scenario for which NOx emissions were re-estimated considering the implementation of the measures. The modelling results demonstrate a decrease of 4-5 μg m in the annual NO levels in the study region. Moreover, the implementation of the selected measures will allow compliance with the NO annual limit values in three of the five air quality stations that measured levels surpassing those established by legislation. This situation demands additional measures that should be implemented at the local level and that particularly focus on the traffic sector. [ABSTRACT FROM AUTHOR]

Micrometeorological conditions in the vicinity of urban buildings strongly influence the requirements that are imposed on building heating and cooling. The goal of the present study, carried out within the Advance Tools for Rational Energy Use towards Sustainability (ATREUS) European research network, is the evaluation of the wind field around buildings with walls heated by solar radiation. Two computational fluid dynamics (CFD) codes were validated against extensive wind-tunnel observations to assess the influence of thermal effects on model performance. The code selected from this validation was used to simulate the wind and temperature fields for a summer day in a specific region of the city of Lisbon. For this study, the meteorological data produced by a non-hydrostatic mesoscale atmospheric model (MM5) were used as boundary conditions for a CFD code, which was further applied to analyze the effects of local roughness elements and thermodynamic conditions on the air flow around buildings. The CFD modelling can also provide the inflow parameters for a Heating, Ventilation and Air Conditioning (HVAC) system, used to evaluate the building energy budgets and to predict performance of the air-conditioning system. The main finding of the present three-dimensional analyses is that thermal forcing associated with the heating of buildings can significantly modify local properties of the air flow. [ABSTRACT FROM AUTHOR]

Signature pigments of photosynthetic green sulfur bacteria (GSB) were found in ancient sediments collected from an abandoned clay quarry located in the Banyoles lacustrine area (Spain). The sediments belong to the Interglacial Waalian of the lower Pleistocene (0.7–1.5 millions years old) and were deposited after a marshy event occurring during that geologic period. Reverse-phase high performance liquid chromatography (RP-HPLC) analyses of acetone:methanol sediment extracts revealed that the main pigments found were carotenoids of both eukaryotic and prokaryotic photosynthetic organisms. In particular, isorenieratene (Isr) and β-isorenieratene (β-Isr) constituted the larger bacterial fraction (35–40% of the total carotenoid content), whereas okenone, a signature pigment of purple sulfur bacteria, accounted for less than 2%. Xanthophylls from oxygenic photosynthetic organisms accounted for the remaining carotenoids. Likewise, traces of degradation products of both bacteriochlorophyll (BChl) and chlorophyll (Chl) were also detected. The low concentration of Chl degradation products made proper identification of these compounds impossible. In contrast, degradation products of BChl- e such as bacteriochlorophyllide- e and bacteriopheophorbide- e were identified in the HPLC analyses, suggesting that chemical degradation of naturally occurring BChl aggregates of GSB was slower in the clay quarry sediments. The presence of signature pigments of brown-colored species of GSB (Isr, β-Isr and degradation products of BChl- e) in the sediments suggests an ancient aquatic environment where GSB were present and where episodes of sulfide-rich anoxia reaching the photic zone could be envisaged. Similarly, the large percentage of algal xanthophylls supports that algae could be an important part of the microbial photosynthetic community in this ancient ecosystem. [ABSTRACT FROM AUTHOR]

The main objective of this work is to analyse how uncertainties in emission data of nitrogen oxides (NOx) and volatile organic compounds (VOC), originated from road traffic, influence the model prediction of ozone (O3) concentration fields. Different methods to estimate emissions were applied and results were compared in order to obtain their variability. Based on these data, different emission scenarios were compiled for each pollutant considering the minimum and the maximum values of the estimated emission range. These scenarios were used as input to the MAR-IV mesoscale modelling system. Simulations have been performed for a summer day in the Northern Region of Portugal. The different approaches to estimate NOx and VOC traffic emissions show a significant variability of absolute values and of their spatial distribution. Comparison of modelling results obtained from the two scenarios presents a dissimilarity of 37% for ozone concentration fields as a response of the system to a variation in the input emission data of 63% for NOx and 59% for VOC. Far beyond all difficulties and approximations, the developed methodology to build up an emission data base shows to be consistent and an useful tool in order to turn applicable an air quality model. Nevertheless, the sensitivity of the model to input data should be considered when it is used as a decision support tool. [ABSTRACT FROM AUTHOR]

The green sulfur bacterium Chlorobium limicola UdG6040 exhibited a significant change in the spectral properties of its antenna when transferred from batch culture to a sulfide-limited chemostat. In steady-state continuous cultures, the in vivo absorption maximum of the culture changed to shorter wavelengths according to the dilution rate. The maximum difference observed was of 15 nm when cells were growing at 0.087 h–1. HPLC analyses revealed that the observed spectral change was caused by a partial enrichment of the original BChl c-containing antenna with BChl d molecules together with a change in the homolog composition of both pigments. The relative amount of BChl d reached a maximum value of 50% when cells were growing at 0.087 h–1. The content of BChl d decreased to less than the 22% when the dilution rate was diminished to 0.015 h–1. An unbalance of pigment synthesis at high dilution rates is suspected to be responsible of the changes observed in the antenna composition. Chlorosomes isolated from Chl. limicola UdG6040 growing at 0.070 h–1 contain organised pools of BChl c and BChl d in equal amounts. [ABSTRACT FROM AUTHOR]

In this paper two mesoscale meteorological models are applied to the Lisbon region. A special concern is directed to the initial conditions and input parameterization in order to assure that equal simulation constraints were imposed to both models. Results obtained for 4 August 1992 (a typical summer day) are compared to meteorological data acquired in three monitoring stations. Both simulations show similar reactions to the mesoscale forcings that occur in the modelling region. The minor differences found between simulation and reality for the meteorological situation can cause major errors in predicting air quality. [ABSTRACT FROM AUTHOR]

The pigment composition of two species of green-colored BChl c-containing green sulfur bacteria ( Chlorobium limicola and C. chlorovibrioides) and two species of brown-colored BChl e-containing ones ( C. phaeobacteroides and C. phaeovibrioides) incubated at different light intensities have been studied. All species responded to the reduction of light intensity from 50 to 1 μEinstein(E) m s by an increase in the specific content of light harvesting pigments, bacteriochlorophylls and carotenoids. At critical light intensities (0.5 to 0.1 μE m s) only brown-colored chlorobia were able to grow, though at low specific rates (0.002 days mg prot). High variations in the relative content of farnesyl-bacteriochlorophyll homologues were found, in particular BChl e and BChl e, which were tentatively identified as [M, E] and [I, E] BChl e, respectively. The former was almost completely lost upon reduction of light intensity from 50 to 0.1 μE m s, whereas the latter increased from 7.2 to 38.4% and from 13.6 to 42.0% in C. phaeobacteroides and C. phaeovibrioides, respectively. This increase in the content of highly alkylated pigment molecules inside the chlorosomes of brown species is interpreted as a physiological mechanism to improve the efficiency of energy transfer towards the reaction center. This study provides some clues for understanding the physiological basis of the adaptation of brown species to extremely low light intensities. [ABSTRACT FROM AUTHOR]

A reversed-phase High Performance Liquid Cromatography (HPLC) method has been developed to accurately separate bacteriochlorophylls c, d and e homologues in a reasonably short run time of 60 minutes. By using this method, two well-defined groups of bacteriochlorophyll homologue peaks can be discriminated. The first one consists of 4 peaks (min 24 to 30), which corresponds to the four main farnesyl homologues. The second peak subset is formed by a cluster of up to 10 minor peaks (min 33 to 40). These peaks can be related with series of several alcohol esters of the different chlorosome chlorophylls. The number of homologues was, however, quite variable depending on both, the bacteriochlorophyll and the bacterial species. The method hereby described, also provides a good separation of other photosynthetic pigments, either bacterial (Bacteriochlorophyll a, chlorobactene, isorenieratene and okenone) or algal ones (Chlorophyll a, Pheophytin a and β-carotene). A preliminary screening of the homologue composition of several green photosynthetic bacterial species and isolates, has revealed different relative quantitative patterns. These differences seem to be related to physiological aspects rather than to taxonomic ones. The application of the method to the study of natural populations avoids the typical drawbacks on the pigment identification of overlapping eukaryotic and prokaryotic phototrophic microorganisms, giving further information about their physiological status. [ABSTRACT FROM AUTHOR]

The acknowledgment of the original article should read as follows: [ABSTRACT FROM AUTHOR]