El sistema dunar de Valdevaqueros: evolución histórica y alternativas de gestión

ResumenLa duna de Valdevaqueros, situada al sur de España, presenta elevadas tasas de migración asociadas a los fuertes vientos de levante que soplan en el estrecho de Gibraltar. Ubicada en una zona de elevada presión humana, su dinámica ha entrado en conflicto con los usos del suelo, provocando una notable repercusión desde los puntos de vista científico y técnico, pero también desde una perspectiva mediática y social. Este trabajo se centra en el análisis de la evolución histórica del sistema dunar desde principios del sigloxx mediante el estudio del material cartográfico y fotográfico disponible, analizando los diferentes estadios que se han sucedido, los mecanismos y agentes naturales que gobiernan su comportamiento, así como las repercusiones derivadas de las diferentes actuaciones en la zona. La intervención sobre el corredor dunar iniciada a principios de 1940 ha condicionado los procesos y la evolución de toda la unidad fisiográfica. La morfodinámica dunar actual se explica por el balance neto de sedimentos. El sistema recibe arena disponible en la zona sumergida transportada por el oleaje de poniente que se acumula en la playa y ensancha la playa seca. El viento de levante erosiona el sedimento en la playa seca y lo transporta hacia la duna. Se estima que en los últimos 50años la playa seca (fetch) ha crecido, en promedio, más de 150m, y que el sistema almacena arena suficiente para mantener estos mecanismos de transporte durante las próximas décadas. A partir de estos resultados, se plantean y analizan diferentes vías de actuación para la gestión integral de la zona.AbstractValdevaqueros dune, in the south of Spain, exhibits high migration rates associated with strong easterly winds in the Strait of Gibraltar. The system is located in an area of high human pressure and its dynamic has collided with land use causing a significant impact from scientific and technical points of view but also from a media and social perspective. This paper focuses on the historical evolution of the dune system since the beginning of the 20th century by studying the available cartographic and photographic material, analyzing the different phases, the mechanisms and natural agents governing the dune behaviour and the implications arising from the activities in the area. The intervention on the dune corridor started in the early 1940s and has conditioned the evolution of all the processes in the physiographic region. The current dune morphodynamics is explained by the sediment budget. The system receives sand from the submerged zone, which is transported by westerly wind waves. This material accumulates and widens the dry beach. The easterly winds erode the sediment in the dry beach and transports it to the dune. In the last fifty years, the dry beach (fetch) has grown, on average, over 150m and the system stores enough sand to sustain these transport mechanisms for decades. From these results, we discuss different alternatives for the integrated management of the area

Exploring the potential of conventional and flash pyrolysis methods for the valorisation of grape seed and chestnut shell biomass from agri-food industry waste

Producción CientíficaResidual biomass is a valuable and growing by-product, but often underutilized. This research aims to investigate the possible strategies for the energetic valorisation of agri-food industry wastes: grape seed and chestnut shell. Pyrolysis thermal process was the selected for this work. Applied to biomass, pyrolysis is a promising method for the simultaneous production of biochar, bio-oil, and gas. Two different pyrolysis processes were conducted: conventional pyrolysis at 750 °C and flash pyrolysis at 750 °C and 850 °C. Flash pyrolysis yielded superior product properties compared to conventional pyrolysis. The gas obtained through flash pyrolysis presented a four-fold higher high heating value due to increased CH4 and H2 content. Bio-oil contains over 90% of polycyclic aromatic hydrocarbons, and calorific value reached up to 32 MJ kg−1 for grape seed, which is 7% more than bioethanol HHV. Biochar can be used both as fuel or as activated carbon precursor due to its high carbon content (91%). Calorific value of chestnut shell biochar (32.7 MJ kg−1), comparable to mineral coals, increased by 72% with respect to the value of this untreated raw material. This work approved the potential of flash pyrolysis as a method to process biomass wastes in a renewable energy scenario.FICYT - Fundación Fomento Asturias Investigación - FEDER (AYUD/2021/51379)Agencia Española de Investigación (PDC2022-133394-I00 y PID2021-124347OB-I00

Prenatal exposure to persistent organic pollutants and anogenital distance in children at 18 months

Background: Anogenital distance (AGD) is a measure of in utero exposure to hormonally active agents. The aim of the present study was to evaluate the association between prenatal exposure to persistent organic pollutants (POPs) and AGD. Methods: POP levels were measured in pregnant women, and the AGD was recorded in 43 offspring at 18 months. We used linear regression models to analyze the association between maternal POP exposure and offspring AGD. We defined the anogenital index (AGI) as AGD divided by weight at 18 months (AGI = AGD / weight at 18 months [mm/kg]) and included this variable in the regression models. Results: AGI measure was 2.35 (0.61) and 1.38 (0.45) in males and females, respectively. AGI was inversely associated with lipid-adjusted concentrations of PBDE-99 (β = -0.28, 95% confidence interval [CI]: -0.51, -0.04) and PBDE-153 (β = -0.61, 95% CI: -1.11, -0.11) in males. We did not find any statistically significant relationship between any POPs and AGI in females. Conclusions: Environmental exposure to POPs may affect genital development and result in reproductive tract alterations with potentially relevant health consequences in maturity. © 2018 The Author(s). Published by S. Karger AG, Basel.This study was funded by grants from FIS-FEDER (PI04/2018, PI09/02311, and PI13/02429), Fundación Cajastur-Liberbank, and Universidad de Oviedo.Peer reviewe

Positive Magneto-Resistance in Quasi-1D Conductors

We present here a simple qualitative model that interpolates between the high and low temperature properties of quasi-1D conductors. At high temperatures we argue that transport is governed by inelastic scattering whereas at low temperatures the conductance decays exponentially with the electron dephasing length. The crossover between these regimes occurs at the temperature at which the elastic and inelastic scattering times become equal. This model is shown to be in quantitative agreement with the organic conductor $TTT_2I_{3-\delta}$. Within this model, we also show that on the insulating side, the positive magnetoresistance of the form $(H/T)^2$ observed in $TTT_2I_{3-\delta}$ and other quasi-1D conductors can be explained by the role spin-flip scattering plays in the electron dephasing rate.Comment: 4 pages, Latex, no figure

The use of lower of higher than recommended doses of folic acid supplements during pregnancy is associated with child attentional dysfunction at 4-5 years of age in the INMA Project

We assessed the association between the use of lower- and higher-than-recommended doses of folic acid supplements (FAs) during pregnancy and attentional function in boys and girls at age of 4-5. We analyzed data from 1329 mother-child pairs from the mother-child cohort INfancia y Medio Ambiente Project (INMA) study. Information on FAs use during pregnancy was collected in personal interviews at weeks 12 and 30, and categorized in <400, 400-999 (recommended dose), and ≥1000 μg/day. Child attentional function was assessed by Conners' Kiddie Continuous Performance Test. Multivariable regression analyses were used to estimate incidence rate ratios (IRR) and beta coefficients with 95% confidence intervals (CI). Compared to recommended FAs doses, the periconceptional use of <400 and ≥1000 μg/day was associated with higher risk of omission errors-IRR = 1.14 (95% CI: 1.01; 1.29) and IRR = 1.16 (95% CI: 1.02; 1.33), respectively. The use of FAs < 400 μg/day and ≥1000 μg/day was significantly associated with deficits of attentional function only in boys. FAs use < 400 μg/day was associated with higher omission errors with IRR = 1.22 and increased hit reaction time (HRT) β = 34.36, and FAs use ≥ 1000 μg/day was associated with increased HRT β = 33.18 and HRT standard error β = 3.31. The periconceptional use of FAs below or above the recommended doses is associated with deficits of attentional function in children at age of 4-5, particularly in boys

Prenatal exposure to NO2 and ultrasound measures of fetal growth in the Spanish INMA cohort

__Background:__ Air pollution exposure during pregnancy has been associated with impaired fetal growth. However, few studies have measured fetal biometry longitudinally, remaining unclear as to whether there are windows of special vulnerability. __Objective:__ The aim was to investigate the impact of nitrogen dioxide (NO2) exposure on fetal and neonatal biometry in the Spanish INMA study. Methods: Biparietal diameter (BPD), femur length (FL), abdominal circumference (AC), and estimated fetal weight (EFW) were evaluated for up to 2,478 fetuses in each trimester of pregnancy. Size at 12, 20, and 34 weeks of gestation and growth between these points, as well as anthropometry at birth, were assessed by SD scores derived using cohort-specific growth curves. Temporally adjusted land-use regression was used to estimate exposure to NO2 at home addresses for up to 2,415 fetuses. Associations were investigated by linear regression in each cohort and subsequent meta-analysis. __Results:__ A 10-μg/m3 increase in average exposure to NO2 during weeks 0-12 was associated with reduced growth at weeks 0-12 in AC (-2.1%; 95% CI: -3.7, -0.6) and EFW (-1.6%; 95% CI: -3.0, -0.3). The same exposure was inversely associated with reduced growth at weeks 20-34 in BPD (-2.6%; 95% CI: -3.9, -1.2), AC (-1.8%; 95% CI: -3.3, -0.2), and EFW (-2.1%; 95% CI: -3.7, -0.2). A less consistent pattern of association was observed for FL. The negative association of this exposure with BPD and EFW was significantly stronger in smoking versus nonsmoking mothers. __Conclusi

Dietary intake of trans fatty acids in children aged 4–5 in Spain: The INMA cohort study

Trans fatty acid (TFA) intake has been identified as a health hazard in adults, but data on preschool children are scarce. We analyzed the data from the Spanish INMA Project to determine the intake of total, industrial and natural TFA, their main sources and the associated socio-demographic and lifestyle factors in children aged 4–5 (n = 1793). TFA intake was estimated using a validated Food Frequency Questionnaire, and multiple linear regression was used to explore associated factors. The mean daily intakes of total, industrial and natural TFA were 1.36, 0.60, and 0.71 g/day, respectively. Ten percent of the children obtained >1% of their energy intake from TFA. The main sources of industrial TFA were fast food, white bread and processed baked goods. Milk, red and processed meat and processed baked goods were the main sources of natural TFA. Having parents from countries other than Spain was significantly associated with higher natural TFA (in mg/day) intake (β 45.5) and television viewing was significantly associated with higher industrial TFA intake (β 18.3). Higher fruits and vegetables intake was significantly associated with lower intakes of all TFAs, whereas higher sweetened beverages intake was significantly associated with lower total and natural TFA intake. Thus, total and industrial TFA intake was associated with less healthy food patterns and lifestyles in Spanish preschool children

The use of lower or higher than recommended doses of folic acid supplements during pregnancy is associated with child attentional dysfunction at 4–5 years of age in the inma project

We assessed the association between the use of lower-and higher-than-recommended doses of folic acid supplements (FAs) during pregnancy and attentional function in boys and girls at age of 4–5. We analyzed data from 1329 mother-child pairs from the mother-child cohort INfancia y Medio Ambiente Project (INMA) study. Information on FAs use during pregnancy was collected in personal interviews at weeks 12 and 30, and categorized in <400, 400–999 (recommended dose), and ≥1000 µg/day. Child attentional function was assessed by Conners’ Kiddie Continuous Performance Test. Multivariable regression analyses were used to estimate incidence rate ratios (IRR) and beta coefficients with 95% confidence intervals (CI). Compared to recommended FAs doses, the periconceptional use of <400 and ≥1000 µg/day was associated with higher risk of omission errors—IRR = 1.14 (95% CI: 1.01; 1.29) and IRR = 1.16 (95% CI: 1.02; 1.33), respectively. The use of FAs < 400 µg/day and ≥1000 µg/day was significantly associated with deficits of attentional function only in boys. FAs use < 400 µg/day was associated with higher omission errors with IRR = 1.22 and increased hit reaction time (HRT) β = 34.36, and FAs use ≥ 1000 µg/day was associated with increased HRT β = 33.18 and HRT standard error β = 3.31. The periconceptional use of FAs below or above the recommended doses is associated with deficits of attentional function in children at age of 4–5, particularly in boys

European birth cohorts for environmental health research

Many pregnancy and birth cohort studies investigate the health effects of early-life environmental contaminant exposure. An overview of existing studies and their data is needed to improve collaboration, harmonization, and future project planning