Application of Pyrolysis-GC/MS for Rapid Assessment of Organic Contamination in Sediments from Barcelona Harbor

Pyrolysis-GC/MS is advantageous as a tool for rapid sediment contamination assessment because of the small sample size required, minimal sample preparation, and its ability to detect a wide variety of organic pollutants as well as naturally-occurring biological materials. Py-GC/MS was applied, together with determination of organic carbon, and major and minor element concentrations, to evaluate potentially contaminated sediments in the port of Barcelona (Spain) and the adjacent Llobregat River delta. Detected contaminant markers, most evident in the Old Port (Port Vell) area, included hopanes and alkylated PAHs (petroleum), sterenes (sewage), C16-C19 phenylalkanes (detergents) and parent PAHs (combusted fuels)

Anàlisi funcional de la central de cicle combinat de Sagunt i estudi de millores del seu procés de refrigeració.

Aquest document recull la memòria d’un estudi tècnic de funcionament d’una central de cicle combinat, més concretament, de la central de cicle combinat de Sagunt. En ell s’han inclòs aspectes tals com l’anàlisi de l’emplaçament i els motius del mateix, la distribució en planta de la instal·lació o l’estudi dels diferents equips dels grups de generació de potència. Així mateix, s’ha fet especial èmfasi en l’anàlisi del sistema de refrigeració de la central esmentada. S’han estudiat els equips que el componen, se n’han calculat els paràmetres de funcionament més rellevants i, finalment, s’han plantejat les següents tres propostes de modificació: Augment del cabal de circulació del circuit de refrigeració un 10% respecte el cabal actual de referència. Disminució del cabal de circulació del circuit de refrigeració un 10% respecte el cabal actual de referència. Substitució del condensador existent per un equip amb un 10% més de superfície de transferència. S’ha estudiat l’efecte de cadascuna d’aquestes propostes en la potència elèctrica generada per la central i, de les que han resultat viables en termes de potència, se n’ha realitzat un petit estudi ambiental, en el que se s’ha calculat el seu efecte en la reducció de les emissions de diòxid de carboni (CO2) i òxids de nitrogen (NOx), i finalment, un breu estudi de costos, per tal de valorar-ne la viabilitat econòmica

Marriage market polarization in the time of college educational expansion

Marriage market polarization in the time of college educational expansion Are societies becoming more polarized between college-educated and non-college-educated people? Is the force of homogamy generating more egalitarian unions at the cost of more polarized societies? In this paper, we examine patterns of assortative mating to investigate the extent to which the force of homogamy (the propensity to marry within the same educational group), the expansion of college education and the gender gap in education are contributing to polarization in the marriage market between college- and non-college-educated populations worldwide. To this end, we assembled census and survey microdata from 120 countries and 408 samples from 1960 to 2011 that represent 98% of the world's population. We developed a simple yet effective decomposition model that neatly assesses the impact of these three forces on couples' education distribution and the corresponding polarization levels. The results show that the force of homogamy and the gender gap in education have played a very limited role in determining the levels of marriage market polarization between college-educated and non-college-educated populations. These levels, which are increasing worldwide, are rather mechanically driven by the share of the population with a college education, which continues to expand in most societies. The feared scenarios predicting the shrinkage and gradual disappearance of mixed couples in favor of compartmentalized partitions between college-educated couples and below-college-educated ones are not occurring.Les societats estan polaritzant-se entre les persones amb formació universitària i les que no tenen estudis universitaris? La força de l'homogàmia genera unions més igualitàries a costa de societats més polaritzades? En aquest treball examinem els patrons d'aparellament assortiu per investigar fins a quin punt la força de l'homogàmia (la propensió a casar-se dins del mateix grup educatiu), l'expansió de l'educació universitària i la bretxa de gènere en l'educació contribueixen a la polarització del mercat matrimonial entre poblacions universitàries i no universitàries. Per a això, vam reunir microdades de censos i enquestes de 120 països i 408 mostres de 1960 a 2011 que representen el 98% de la població mundial. Hem desenvolupat un model de descomposició senzill però eficaç que avalua adequadament l'impacte d'aquestes tres forces en la distribució educativa de les parelles i els nivells de polarització corresponents. Els resultats mostren que la força de l'homogàmia i la bretxa de gènere en l'educació han tingut un paper molt limitat a l'hora de determinar els nivells de polarització del mercat matrimonial entre poblacions educades en universitat i no universitàries. Aquests nivells, que creixen a nivell mundial, es veuen impulsats mecànicament per la proporció de la població amb una formació universitària, que continua expandint-se en la majoria de les societats. No es produeixen els temuts escenaris que preveuen la contracció i la desaparició gradual de parelles mixtes en favor de particions compartimentades entre parelles educades a la universitat i les que no tinguin formació universitària.¿Están las sociedades cada vez más polarizadas entre personas con educación universitaria y personas sin educación universitaria? ¿La fuerza de la homogamia está generando uniones más igualitarias a costa de sociedades más polarizadas? En este artículo, examinamos los patrones de apareamiento selectivo para investigar hasta qué punto la fuerza de la homogamia (la propensión a casarse dentro del mismo grupo educativo), la expansión de la educación universitaria y la brecha de género en la educación están contribuyendo a la polarización en el mercado matrimonio entre las poblaciones con educación universitaria y no universitaria en todo el mundo. Con este fin, reunimos microdatos de censos y encuestas de 120 países y 408 muestras de 1960 a 2011 que representan el 98% de la población mundial. Desarrollamos un modelo de descomposición simple pero efectivo que evalúa cuidadosamente el impacto de estas tres fuerzas en la distribución de la educación de las parejas y los niveles de polarización correspondientes. Los resultados muestran que la fuerza de la homogamia y la brecha de género en la educación han desempeñado un papel muy limitado en la determinación de los niveles de polarización del mercado matrimonial entre las poblaciones con educación universitaria y sin educación universitaria. Estos niveles, que están aumentando en todo el mundo, están impulsados más bien mecánicamente por la proporción de la población con educación universitaria, que continúa expandiéndose en la mayoría de las sociedades. Los temidos escenarios que predicen la contracción y la desaparición gradual de las parejas mixtas a favor de particiones compartimentadas entre parejas con educación universitaria y parejas con educación inferior a la universidad no se están produciendo

Decomposing patterns of college marital sorting in 118 countries : structural constraints versus assortative mating

Two broad forces shape the patterns of marital sorting by education: structural constraints and assortative mating. However, we lack specific and comparative quantification of the extent of these two forces. In this paper, we measure the specific contributions of (i) assortative mating, (ii) the level of college education and (iii) the gender gap in education on marital sorting patterns and the corresponding polarization levels between college and non-college educated couples. Unlike previous studies, we adopt a large- cross-national approach including 118 countries and more than 258 observations spanning from 1960 up to 2011. Methodologically, we develop counterfactual modelling techniques to compare observed patterns of marital sorting with expected patterns derived from alternative structural and assortative mating conditions. Our findings indicate that changes in college marital sorting and increases in polarization between college- and non-college-educated populations are overwhelmingly driven by structural constraints, namely the expansion of college education. Instead, educational assortative mating plays a limited role - accounting only for 5% of the observed changes in marriage market polarization

National age and coresidence patterns shape COVID-19 vulnerability

Based on harmonized census data from 81 countries, we estimate how age and coresidence patterns shape the vulnerability of countries' populations to outbreaks of coronavirus disease 2019 (COVID-19). We estimate variation in deaths arising due to a simulated random infection of 10% of the population living in private households and subsequent within-household transmission of the virus. The age structures of European and North American countries increase their vulnerability to COVID-related deaths in general. The coresidence patterns of elderly persons in Africa and parts of Asia increase these countries' vulnerability to deaths induced by within-household transmission of COVID-19. Southern European countries, which have aged populations and relatively high levels of intergenerational coresidence, are, all else equal, the most vulnerable to outbreaks of COVID-19. In a second step, we estimate to what extent avoiding primary infections for specific age groups would prevent subsequent deaths due to within-household transmission of the virus. Preventing primary infections among the elderly is the most effective in countries with small households and little intergenerational coresidence, such as France, whereas confining younger age groups can have a greater impact in countries with large and intergenerational households, such as Bangladesh

Geochemical Investigation of an Offshore Sewage Sludge Deposit, Barcelona, Catalonia, Spain

For 20 years ending in the 1990’s the city of Barcelona discharged the products from a large primary sewage treatment plant directly into the Mediterranean Sea via underwater conduits. About ca. 3 million m3 of relict sewage sludge, rich in organic matter and heavy metals, has spread over an elongated area offshore, due to successive ruptures of the conduits. The use of the discharge pipes ceased, but he sludge deposit remains in place for the time being. To understand the history and present state of the sludge deposit in advance of future remediation, a program of geophysical mapping, sampling, and analytical work was undertaken. Rock Eval pyrolysis, although created for use in petroleum prospecting, can also be applied to environmental contamination studies. It offers a simple means to effectively delineate the sludge deposit, with the S2 parameter and the hydrogen and oxygen indices particularly useful. On the molecular level, the sludge flash pyrolysis products notably include relatively abundant C27 and C29 sterenes and steranes, likely produced from the pyrolysis of fecal and other steroids, including coprostanol, in the sewage sludge. Linear alkylbenzenes and trialkylamines, derived from surfactant residues in the sludge, are also detected. The indoles detected are likely the pyrolysis products of proteins, while the alkylnitriles and alkylamides in the pyrolyzate likely derive from bacterial biomass. Principal components analysis aided the interpretation of the large geochemical dataset and a geographic information system enabled the three-dimensional visualization of the results in their geospatial context. The distinctive pyrolysis products and the trace elements would be geochemical markers useful in planning and assessing a future remediation program. The recognition of a distinctive sewage pyrolysis-GC/MS signature in this deposit would facilitate the use of this method in the detection of sewage-contaminated sediments in urban waterways worldwide

Organic-rich shales from internal Betic basins (SE Spain) : potential source rocks analogs for the pre-Messinian Salt play in the western Mediterranean

Southeastern Spain has a large number of Late Neogene basins with substantial evaporitic deposits that developed under an overall NNW-SSE compressional regime related to the African-European tectonic plates collision. Located in the Betic Cordillera, they can be considered as marginal Mediterranean basins that became gradually isolated during the Tortonian and Early Messinian due to tectonic uplift. Different evaporitic units accumulated in these basins during isolation and, in several cases, evaporitic conditions were associated to episodes of important organic matter accumulation. Results obtained from Late Tortonian to Early Messinian shales collected from boreholes, mines and outcrops in the internal Betic basins of Las Minas de Hellín, Cenajo and Socovos are presented. The organic matter was studied under fluorescence and scanning electron microscopy (SEM), and the main geochemical characteristics defined. They show a relation between organic-rich intervals with high potential of hydrocarbon generation, native sulfur, bio-induced dolomite and evaporitic deposits. These organicrich shales can be found before, during and after the evaporitic episodes. Results from the present study are compared with those previously obtained in the pre-evaporitic deposits of the Lorca Basin that showed high oil generation potential, a restricted-marine origin of the organic matter and a low degree of maturity. The occurrence of such potential source rocks in several basins points to a broad regional distribution. At a larger scale, in the Mediterranean Basin, organic-rich sediments were deposited before and during the Messinian Salinity Crisis. The studied examples could represent analogs for potential source rocks of the pre-Messinian salt play in the Western Mediterranea

Characterization of asphaltic oil occurrences from the southeastern margin of the Basque-Cantabrian Basin, Spain

A geochemical investigation has been undertaken on biodegraded hydrocarbons in outcropping reservoirs of the south-eastern margin of the Basque-Cantabrian Basin (Álava sector). The aims of the study were the characterization of the geochemical features and biodegradation level of these hydrocarbons, and the evaluation of their resemblance to oils from the Ayoluengo onshore oil field by means of isotopic analyses and gas chromatography-mass spectrometry techniques. Most of the samples lack n-alkanes, soprenoids, low molecular weight aromatic compounds, steranes, homohopanes, diasteranes and triaromatic steroids, whereas hexacyclic and heptacyclic alkanes appear as key compounds although some structures were not totally elucidated. Thermal maturity has been assessed with several parameters and a calculated-equivalent vitrinite reflectance value of around 0.8% was estimated. In addition, gammacerane content, diasterane-to-sterane ratio and C35 to C34 hopanes ratio suggest that the Álava oil shows were derived from a carbonate rock deposited in a reducing, water-stratified and possibly hypersaline environment. Isotopic signatures and other data confirmed that these hydrocarbons are not genetically related to the oils from Ayoluengo and, consequently, their origin is associated with a yet unknown source rock in the basin

Organic-rich shales from internal Betic basins (SE Spain): potential source rocks analogs for the pre-Messinian Salt play in the western Mediterranean

under an overall NNW-SSE compressional regime related to the African-European tectonic plates collision. Located in the Betic Cordillera, they can be considered as marginal Mediterranean basins that became gradually isolated during the Tortonian and Early Messinian due to tectonic uplift. Different evaporitic units accumulated in these basins during isolation and, in several cases, evaporitic conditions were associated to episodes of important organic matter accumulation. Results obtained from Late Tortonian to Early Messinian shales collected from boreholes, mines and outcrops in the internal Betic basins of Las Minas de Hellín, Cenajo and Socovos are presented. The organic matter was studied under fluorescence and scanning electron microscopy (SEM), and the main geochemical characteristics defined. They show a relation between organic-rich intervals with high potential of hydrocarbon generation, native sulfur, bio-induced dolomite and evaporitic deposits. These organicrich shales can be found before, during and after the evaporitic episodes. Results from the present study are compared with those previously obtained in the pre-evaporitic deposits of the Lorca Basin that showed high oil generation potential, a restricted-marine origin of the organic matter and a low degree of maturity. The occurrence of such potential source rocks in several basins points to a broad regional distribution. At a larger scale, in the Mediterranean Basin, organic-rich sediments were deposited before and during the Messinian Salinity Crisis. The studied examples could represent analogs for potential source rocks of the pre-Messinian salt play in the Western Mediterranean