This research aims to assess the influence of coastal cities around the world. The main goals are focused on quantifying the urbanization process in coastal areas. Also, the relationship between ...urban growth and different coastal conditions was studied. In this research two sources of information were used: city population databases of United Nations and Google Earth remote sensing. The method is focused on a detailed study of all cities with over 100,000 inhabitants, from 1945 to 2012.
The results show that half of population living in cities with over 100,000 inhabitants are within 100 km from the coast. This urban settlement has a particular pattern on the south, where is observed a “southern ridge” with a greater growth. The relationship between this development and coastal issues about geographical distribution, ecosystems, social and economic points; allows obtaining areas of interest for integrated coastal management.
•Quantification of colonization process of coastal urban areas around the world.•CCAs around the world have increased by 4.5 times since 1945.•Number of CCAs next to mangroves increased from 13% to 20% in the last 7 decades.•Coastal fronts with the most dynamic cities in the world draw a “southern ridge”.•88% of CCAs are linked to port infrastructures.
In the zebrafish (Danio rerio), regeneration and fibrosis after cardiac injury are not mutually exclusive responses. Upon cardiac cryoinjury, collagen and other extracellular matrix (ECM) proteins ...accumulate at the injury site. However, in contrast to the situation in mammals, fibrosis is transient in zebrafish and its regression is concomitant with regrowth of the myocardial wall. Little is known about the cells producing this fibrotic tissue or how it resolves. Using novel genetic tools to mark periostin b- and collagen 1alpha2 (col1a2)-expressing cells in combination with transcriptome analysis, we explored the sources of activated fibroblasts and traced their fate. We describe that during fibrosis regression, fibroblasts are not fully eliminated but become inactivated. Unexpectedly, limiting the fibrotic response by genetic ablation of col1a2-expressing cells impaired cardiomyocyte proliferation. We conclude that ECM-producing cells are key players in the regenerative process and suggest that antifibrotic therapies might be less efficient than strategies targeting fibroblast inactivation.
► Indigo wastewaters are successfully treated with a solar assisted oxidation reaction. ► Using ferrous oxalate complexes, the efficiency of the treatment increases. ► Increasing peroxide ...concentrations did not improve the treatment substantially. ► The best removals of TOC and COD were reached with the smallest peroxide dose. ► A final complete biodegradability was obtained for these wastewaters.
This study assessed the applicability of a ferrous oxalate mediated photo-Fenton pretreatment for indigo-dyed wastewaters as to produce a biodegradable enough effluent, likely of being derived to conventional biological processes. The photochemical treatment was performed with ferrous oxalate and hydrogen peroxide in a Compound Parabolic Concentrator (CPC) under batch operation conditions. The reaction was studied at natural pH conditions (5–6) with indigo concentrations in the range of 6.67–33.33mgL−1, using a fixed oxalate-to-iron mass ratio (C2O42−/Fe2+=35) and assessing the system's biodegradability at low (257mgL−1) and high (1280mgL−1) H2O2 concentrations. In order to seek the optimal conditions for the treatment of indigo dyed wastewaters, an experimental design consisting in a statistical surface response approach was carried out. This analysis revealed that the best removal efficiencies for Total Organic Carbon (TOC) were obtained for low peroxide doses. In general it was observed that after 20kJL−1, almost every treated effluent increased its biodegradability from a BOD5/COD value of 0.4. This increase in the biodegradability was confirmed by the presence of short chain carboxylic acids as intermediate products and by the mineralization of organic nitrogen into nitrate. Finally, an overall decrease in the LC50 for Artemia salina indicated a successful detoxification of the effluent.
This paper presents the evaluation of emissions from vehicle operations in a domain of 300m×300m covering a complex urban roundabout with high traffic density in Madrid. Micro-level simulation was ...successfully applied to estimate the emissions on a scale of meters. Two programs were used: i) VISSIM to simulate the traffic on the square and to compute velocity-time profiles; and ii) VERSIT+micro through ENVIVER that uses VISSIM outputs to compute the related emissions at vehicle level. Data collection was achieved by a measurement campaign obtaining empirical data of vehicle flows and traffic intensities. Twelve simulations of different traffic situations (scenarios) were conducted, representing different hours from several days in a week and the corresponding NOX and PM10 emissions were estimated. The results show a general reduction on average speeds for higher intensities due to braking-acceleration patterns that contribute to increase the average emission factor and, therefore, the total emissions in the domain, especially on weekdays. The emissions are clearly related to traffic volume, although maximum emission scenario does not correspond to the highest traffic intensity due to congestion and variations in fleet composition throughout the day. These results evidence the potential that local measures aimed at alleviating congestion may have in urban areas to reduce emissions. In general, scenario-averaged emission factors estimated with the VISSIM-VERSIT+micro modelling system fitted well those from the average-speed model COPERT, used as a preliminary validation of the results. The largest deviations between these two models occur in those scenarios with more congestion. The design and resolution of the microscale modelling system allow to reflect the impact of actual traffic conditions on driving patterns and related emissions, making it useful for the design of mitigation measures for specific traffic hot-spots.
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•Microscale traffic and related NOX and PM10 emissions were simulated in a hot-spot.•12 representative traffic situations throughout the week were analysed.•Peak-hour emission factors up to 43% higher than those for free-flow conditions.•Non-proportional dependency of total emissions with intensity in saturated conditions•Emission results from ENVIVER fit well with the widely validated model COPERT 4.
This paper applies the Life Cycle Assessment methodology to develop a simple method to calculate the carbon footprint of the municipal solid waste treatment stage. This simple and structured ...methodological procedure takes into account: i) direct greenhouse gas emissions produced in waste treatment, taking place within the city boundary (scope 1 of international carbon footprint standards); ii) indirect greenhouse gas emissions related to the use of grid-supplied electricity, as well as fuel production and distribution (scopes 2 and 3 emissions as per international carbon footprint standards); and iii) avoided greenhouse gas emissions as a result of the products obtained (if any) that can replace other products or the raw materials used to produce them. Madrid City (a representative European city), the capital of Spain, was used as a case study to prove the validity and usefulness of the proposed methodology. In this city, 344 kg of municipal solid wastes were produced per inhabitant in 2013. These wastes were collected separately in different fractions (packaging, glass, paper/cardboard and mixed waste, including organic material). Mixed waste and packaging fractions were processed at the Valdemingómez Technology Park. The current treatment stage was compared with several alternative scenarios which describe hypothetical management routes for the different waste fractions. The carbon footprint for the current situation is equal to 224 kg CO2 eq/twaste. In comparison to the worst situation, corresponding to the scenario in which municipal wastes were landfilled without energy recovery, the current scenario reduces its carbon footprint by 1597 kg CO2 eq/twaste (a reduction of 88%). Improvements in the material separation and recovery processes, along with the implementation of biological treatments for the organic fraction, clearly contribute to reducing the carbon footprint of the municipal solid wastes handled in the city of Madrid.
According to the obtained results, the scenarios based on a total recovery of valuable materials and waste-to-energy or anaerobic digestion treatments present the lowest carbon footprint because burden avoided is more important than direct and indirect emissions from treatments. In addition, the consumption of electricity and the emissions derived from its generation (mix of generation), can increase the carbon footprint of power-intensive treatments.
•Methodology to compute CF of MSW management treatments.•Scenarios based on biological treatments of MSW have less impact on climate change.•CF of real situation in Madrid was 224 CO2 eq/tMSW in 2013.•Current CF is 88% lower than the ”worst” situation (landfilling/no biogas recovery).•As sensitivity analysis shows, electricity generation mix sharply influences on CF.
Background
The epicardium is the outer mesothelial layer of the heart. It encloses the myocardium and plays key roles in heart development and regeneration. It derives from the proepicardium (PE), ...cell clusters that appear in the dorsal pericardium (DP) close to the atrioventricular canal and the venous pole of the heart, and are released into the pericardial cavity. PE cells are advected around the beating heart until they attach to the myocardium. Bmp and Notch signaling influence PE formation, but it is unclear how both signaling pathways interact during this process in the zebrafish.
Results
Here, we show that the developing PE is influenced by Notch signaling derived from the endothelium. Overexpression of the intracellular receptor of notch in the endothelium enhances bmp expression, increases the number of pSmad1/5 positive cells in the DP and PE, and enhances PE formation. On the contrary, pharmacological inhibition of Notch1 impairs PE formation. bmp2b overexpression can rescue loss of PE formation in the presence of a Notch1 inhibitor, but Notch gain‐of‐function could not recover PE formation in the absence of Bmp signaling.
Conclusions
Endothelial Notch signaling activates bmp expression in the heart tube, which in turn induces PE cluster formation from the DP layer.
Key Findings
Notch is active on endothelial cells but not on EPDCs cells during PE formation.
Endothelial Notch signaling activates Bmp expression in the heart‐tube.
Notch and Bmp pathways induce PE cluster formation from the DP layer.
A model was developed to simulate the sewage sludge gasification in an atmospheric fluidised bed gasifier using Aspen Plus. The model here presented was based on the Gibbs free energy minimisation ...and the restricted equilibrium method was used to calibrate it against previously published experimental data obtained in a lab-scale gasification plant. A sensitivity analysis of the model was carried out by modifying parameters such as the temperature, equivalence ratio (ER) and the steam-to-biomass ratio. The modeled results were in good agreement with the experimental data (especially when air was used as gasifying agent) and reproduced satisfactorily the experimental trends found for the gas composition, the carbon conversion (Xc) and the cold gas efficiency (CGE) under different gasification conditions. Operating at higher temperatures increased the production of H
2
and CO, as well as the Xc and the CGE. The increase in ER produced higher Xc, yet the CGE experienced slight changes due to a decrease in the lower heating value of the resulting syngas, as well as the oxidation of combustible gases. The use of air+steam as gasifying agent increased the H
2
content of the produced gases but decreased the accuracy of the model.
Implications: Gasification is an available alternative to produce energy as well as several raw materials from sewage sludge. The syngas obtained from this technology totally depends on the type of gasifier and the operation conditions, which can be optimized with the help of models. In this work, a relatively simple model was built using ASPEN PLUS. Despite its simplicity, the outputs of the model are in good agreement with experimental results what makes its use interesting for assessing scaling-up possibilities from lab-scale to pilot-scale gasification processes.
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•The effect of some primary measures on sewage sludge gasification products was tested.•Higher throughputs decreased the H2 content of the syngas and increased tar production.•The use ...of dolomite showed gravimetric tar removal efficiencies of up to 71%.•Dolomite performance remained fairly constant over the range of studied throughputs.•Under the tested experimental conditions, syngas dew point never dropped below 110°C.
The influence of throughput (TR), steam and the use of dolomite (as primary catalyst) over the sewage sludge gasification products was investigated. For this purpose, experiments were conducted in an atmospheric fluidised bed reactor using air and air+steam as gasifying agents. The analysis of the results was mainly focussed on the gas composition, the gravimetric tar production, and the GC-detectable tar composition (and dew point estimations). According to the obtained results, higher TRs decreased the H2 content of the produced gas and clearly increased the gravimetric tar production. The use of air+steam, especially in the presence of dolomite, increased the H2 content (between 20% and 36%) and decreased the gravimetric tar production over all the tested TR, reaching tar removal efficiencies of up to 71%. Regarding the GC-detectable tar, higher TRs increased the heavy polyaromatic hydrocarbons production, steam slightly increased the water soluble tar content while the use of dolomite decreased the yield of all the tar classes except light aromatic hydrocarbons. Under the tested gasification conditions, the gas dew point never dropped below 110°C, value far above the recommended temperature when the syngas is to be used for engine applications.
•Tar removal efficiencies of olivine, alumina and dolomite are compared.•Higher throughputs decreased the H2 content of the syngas and increased tar production.•The use of steam improved by 20% ...catalysts performance in gravimetric tar removal.•Only dolomite performance remained fairly constant over the range of studied throughputs.•Under the tested experimental conditions, syngas dew point never dropped below 108°C.
This work shows the influence of parameters such as temperature, throughput (TR), the gasifying agent and the use of catalysts (olivine, alumina and dolomite) on the products resulting from the gasification of sewage sludge on a fluidised bed. An increase in temperature of between 750 and 850°C rises the production of combustible gas and reduces the production of gravimetric tar (by 65%, at TR=110kg/hm2, and 49% at TR=322kg/hm2), while the increase in TR at a given temperature produces the contrary effects. An analysis of the composition of the tar detected by gas chromatography (GC), shows that higher temperatures increase the concentration of polycyclic aromatic hydrocarbons (PAH). In spite of all the catalysts being active in tar removal, dolomite showed the most marked results in the air tests, with a reduction in the production of gravimetric tar of 40–50% and a conversion of the heavy PAHs (4–7 aromatic rings) of up to 90%. The combined use of a catalyst and air+steam increases the H2 and CO2 content in the synthesis gas and reduces the CO, CH4 and CnHm production, in addition to improving by 20% the catalysts performance in gravimetric tar removal compared to the tests with catalyst and air. Under the evaluated gasification conditions, the dew point of the gas was never below 108°C, which means that technical problems could be expected due to tar condensation if the synthesis gas were to be used in combustion engines without applying additional tar removal measures.
Coastal and marine areas represent one of the most relevant spaces on a global scale to address management and conservation processes. Firstly, this is due to the interactions that characterise the ...area of exchange between land and sea. Secondly, it is the area where the main population settlements are located. However, there is no agreed definition of the scope of the coastal zone for management, and legal delimitations usually simplify the reality, making it impossible to develop Ecosystem Based Management in these areas. The research advances on a proposal for a conceptual and geographical delimitation of coastal areas from a socio-ecological perspective. The results show a delimitation of the coastal area based on two large geographical areas: The Coast and the Coastal Zone. The first one includes the Coastal Water, the Intertidal Area and the Shoreland. Seconly, the Coastal Zone is fundamental for understanding certain ecosystemic and social phenomena, and includes two units: Coastal Zone Water and Coastal Land. The proposed socio-ecological limits do not always coincide with the legal limits, which is why this article analyses in depth, for the case of Andalusia (Spain), the state and regional legislation on coastal matters. With all this, ideas are proposed on which to introduce socio-ecological delimitation into the legal limits and thus advance towards Ecosystem-Based Management in coastal and marine areas.
•Coastal and marine areas need to be delimited for management.•Socio-ecological approach allows for a reality-based delimitation of the coast.•Spanish legislation focuses on the delimitation of intertidal spaces.•Incorporating the near marine allows for a more ICZM.•The coastal socio-ecological system allows progress towards EBM.
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