375 research outputs found

    Microbial mediated formation of Fe-carbonate minerals under extreme acidic conditions

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    Discovery of Fe-carbonate precipitation in Rio Tinto, a shallow river with very acidic waters, situated in Huelva, South-western Spain, adds a new dimension to our understanding of carbonate formation. Sediment samples from this low-pH system indicate that carbonates are formed in physico-chemical conditions ranging from acid to neutral pH. Evidence for microbial mediation is observed in secondary electron images (Fig. 1), which reveal rod-shaped bacteria embedded in the surface of siderite nanocrystals. The formation of carbonates in Rio Tinto is related to the microbial reduction of ferric iron coupled to the oxidation of organic compounds. Herein, we demonstrate for the first time, that Acidiphilium sp. PM, an iron-reducing bacterium isolated from Rio Tinto, mediates the precipitation of siderite (FeCO3) under acidic conditions and at a low temperature (30°C). We describe nucleation of siderite on nanoglobules in intimate association with the bacteria cell surface. This study has major implications for understanding carbonate formation on the ancient Earth or extraterrestrial planets.European research project ERC-250350/IPBSL. A.S.-N.acknowledges support from the P11-RNM-7067 (Junta de Andaluc a-C.E.I.C.-S.G.U.I.T.) projectPeer Reviewe

    Storage and demand response contribution to firm capacity: Analysis of the Spanish electricity system

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    Provision of firm capacity will become a challenge in power systems dominated by renewable generation. This paper analyzes the competitiveness and role of battery storage, six types of pumped-hydro storage, open cycle gas turbine (OCGT), and demand response (DR) technologies in providing the firm capacity required to guarantee the security of supply in a real-size power system such as the Spanish one in horizon 2030. The paper contributes with detailed and realistic modeling of the DR capabilities. Demand is disaggregated by sector and activities and projected towards 2030, applying a growth rate by activity. The load flexibility constraints are considered to ensure the validity of the results. A generation operation planning and expansion model, SPLODER, is conveniently upgraded to properly represent the different storage alternatives addressed in the paper. The results highlight the importance of considering demand response for evaluating long-term firm capacity requirements, showing a non-negligible impact on the investment decisions on the amount of firm capacity required in the system and the optimal shares of wind and solar PV renewable generation. Results also show the dominance of cost-competitiveness of pumped hydro and OCGTs over batteries. Additionally, capacity payments are required to support firm capacity providers’ investments. © 2022This research has been carried out thanks to the Iberdrola Chair on Energy and Innovation and the funding of the RETOS COLABORACIÓN program of the Spanish Ministry of Science and Innovation and the Spanish State Research Agency (project “Platform of innovative models to accelerate the energy decarbonization of the economy (MODESC)”, with reference number RTC2019-007315-3 ). This research is also supported by the Spanish Ministry of Economy and Competitiveness MINECO through BC3 María de Maeztu excellence accreditation MDM-2017-0714

    Relationship between Salmonella infection, shedding and serology in fattening pigs in low–moderate prevalence areas

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    Salmonella is a major foodborne pathogen causing important zoonosis worldwide. Pigs asymptomatically infected in mesenteric lymph nodes (MLN) can be intermittent shedders of the pathogen through faeces, being considered a major source of human infections. European baseline studies of fattening pig salmonellosis are based on Salmonella detection in MLN. This work studies the relationship between Salmonella infection in MLN and intestinal content (IC) shedding at slaughter and the relationship between the presence of the pathogen and the serologic status at farm level. Mean Salmonella prevalence in the selected pigs (vertically integrated production system of Navarra, Spain) was 7.2% in MLN, 8.4% in IC and 9.6% in serum samples. In this low–moderate prevalence context, poor concordance was found between MLN infection and shedding at slaughter and between bacteriology and serology. In fact, most of shedders were found uninfected in MLN (83%) or carrying different Salmonella strains in MLN and in IC (90%). The most prevalent Salmonellae were Typhimurium resistant to ACSSuT ± Nx or ASSuT antibiotic families, more frequently found invading the MLN (70%) than in IC (33.9%). Multivariable analysis revealed that risk factors associated with the presence of Salmonella in MLN or in IC were different, mainly related either to good hygiene practices or to water and feed control, respectively. Overall, in this prevalence context, detection of Salmonella in MLN is an unreliable predictor of faecal shedding at abattoir, indicating that subclinical infections in fattening pigs MLN could have limited relevance in the IC shedding.info:eu-repo/semantics/acceptedVersio

    Personality in patients with migraine evaluated with the "Temperament and Character Inventory"

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    The objective of this study was to assess the personality profile of a sample of Mexican patients with migraine using the Temperament and Character Inventory (TCI). A cross-sectional study was performed including adult migraine patients identified from the outpatient neurology clinics of two large teaching hospitals in Mexico City. Patients were asked to voluntarily participate in the study. A physician conducted a standardised diagnostic interview adhering to the criteria of the International Headache Society (IHS). Patients were interviewed and administered the TCI. We used two healthy controls groups and a third group of non-migraine pain controls. One hundred and fortytwo subjects with migraine, 108 healthy blood donors, 269 young healthy controls and 30 patients with non-migraine pain (NMP) were included in the study. Patients with migraine had higher scores in the dimension harm avoidance (HA) and all its sub-dimensions (p<0.05) than healthy patients. Patients with non-migraine pain had high scores in HA and low scores in novelty seeking, self-directedness and cooperativeness. Blood donors had high scores in the following subdimensions: HA1, HA4 and C3 (Cooperativeness). Personality features consistent with migraine are avoidance, rigidity, reserve and obsessivity. Our study shows that patients with chronic pain share some of the personality features of patients with migraine but their TCI profile could be indicative of cluster C avoidant personality. Blood donors were shown to have more energy, with a tendency to help other people and be more optimistic. The results support serotoninergic involvement as explaining the physiopathology of migraine

    Results from Bottom Trawl Survey on Flemish Cap of June-July 2021

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    A stratified random bottom trawl survey on Flemish Cap was carried out from 12 July to 9 August 2021. Following the same procedures as in previous years, the area surveyed extends up to depths of 800 fathoms (1460 meters) and 181 fishing stations were planned. The survey was carried out by the R/V Vizconde de Eza with the usual survey gear (Lofoten). A total of 181 valid hauls were made, 120 up to 730 meters depth and 61 up to 1460 meters. Survey results are presented, including abundance indices of the main commercial species and age distributions for cod, redfish, American plaice, Greenland halibut, roughhead grenadier, squid and shrimp. The general indexes for this year are estimated taken into account the traditional swept area (strata 1-19, up to depths of 730 m.) and the total area surveyed (strata 1-34, up to depths of 1460 m.).Versión del editor

    Protection of Possessors in Classical Roman Law -From the Viewpoint of Buyer Protection- (2)

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    We studied the formation of Mg-rich carbonate in culture experiments using different aerobic bacterial strains and aqueous Mg/Ca ratios (2 to 11.5) at Earth surface conditions. These bacteria promoted the formation of microenvironments that facilitate the precipitation of mineral phases (dolomite, huntite, high Mg-calcite and hydromagnesite) that were undersaturated in the bulk solution or kinetically inhibited. Dolomite, huntite, high Mg-calcite, hydromagnesite and struvite precipitated in different proportions and at different times, depending on the composition of the medium. The Mg content of dolomite and calcite decreased with an increasing Ca concentration in the medium. The stable carbon isotope composition of the Mg-rich carbonate precipitates reflected the isotope composition of the organic compounds present in the media, suggesting that microbial metabolism strongly influenced the carbon isotope composition of biomediated carbonates. We observed that Ca-enriched carbonate precipitates have relatively low carbon isotope composition. These results provide insights into the mechanism(s) of carbonate formation in natural systems, and they are of fundamental importance for understanding modern environments in which carbonate minerals form as a window into the geologic past

    Consumo de tabaco y práctica de actividad física en una población melillense

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    Introduction: Tobacco use is considered a risk factor in the development of multiple pathologies at the pulmonary and cardio-vascular levels, among others. In this sense, the practice of physical activity is considered a factor of protection. Objective: To describe the socio-demographic variables and quality of life in terms of tobacco use and the practice of physical activity in a Melillense population. Material and Method: Research work with quantitative design, descriptive and cross section of a sample of residents in Melilla, about tobacco use and the practice of physical activity. Results: More than three-quarters of the participants said no smoking and three out of ten subjects did not perform any physical activity. Conclusions: We must continue working to strengthen healthy behaviors in the population, in relation to the consumption of harmful substances and the practice of physical activity.Introducción: El consumo de tabaco es considerado factor de riesgo ante el desarrollo de múltiples patologías a nivel pulmonar y cardio-vascular, entre otras. En este sentido, la práctica de actividad física es considerada un factor de protección. Objetivo: Describir las variables socio-demográficas y de calidad de vida en cuanto al consumo de tabaco y la práctica de actividad física en una población Melillense. Material y Método: Trabajo de investigación con diseño cuantitativo, de carácter descriptivo y corte transversal de una muestra de residentes en Melilla, acerca del consumo de tabaco y la práctica de actividad física. Resultados: Más de tres cuartas partes de los participantes manifestaron no fumar tabaco y tres de cada diez sujetos no realizaba ningún tipo de actividad física.&nbsp;Conclusiones: Hay que seguir trabajando por afianzar conductas saludables en la población, en relación al consumo de sustancias nocivas y la práctica de actividad física

    Hábitos de actividad física y conductas sedentarias en escolares de Educación Primaria

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    The objective of the present study is to describe the anthropometric characteristics and lifestyle in Primary School (PS) students and to observe if there are differences in the variables analyzed regarding sex, school grade, educational cycle, number of weekly Physical Education sessions and type of educational center. In this study, 793 PS students participated. Among the results obtained, significantly higher values ​​were observed in the group of boys, compared to the group of girls, in the weekly practice of physical exercise (p &lt;0.01) and in the recreative use of screens on weekends (p &lt;0.01). Significant differences were also found depending on the school grade, the educational cycle and the type of educational center. These results show the importance of understanding the specific characteristics of the groups of schoolchildren, with the objective of being efficient in the necessary implementation of policies encouraging the practice of PA.Los objetivos del presente estudio fueron describir las características antropométricas y los hábitos de vida de escolares de Educación Primaria Obligatoria (EPO) y observar si existen diferencias en las variables analizadas atendiendo al sexo, curso escolar, internivel, número de sesiones semanales de Educación Física y tipo de centro educativo. En este estudio participaron 793 estudiantes de EPO. Entre los resultados obtenidos, se observaron valores significativamente más altos en el grupo de chicos con respecto al grupo de chicas en la práctica semanal de AF reglada (p &lt; 0,01) y en el uso ocioso de pantallas los fines de semana (p &lt; 0,01). También se hallaron diferencias significativas atendiendo al curso, internivel y tipo de centro. Estos resultados evidencian la importancia de conocer las características específicas de los grupos de escolares, con el objetivo de ser eficientes en la necesaria implementación de políticas de fomento de la práctica de AF

    Hierarchical Stellar Structures in the Local Group Dwarf Galaxy NGC 6822

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    We present a comprehensive study of the star cluster population and the hierarchical structure in the clustering of blue stars with ages <~ 500 Myr in the Local Group dwarf irregular galaxy NGC 6822. Our observational material comprises the most complete optical stellar catalog of the galaxy from imaging with the Suprime-Cam at the 8.2-m SUBARU Telescope. We identify 47 distinct star clusters with the application of the nearest-neighbor density method to this catalog for a detection threshold of 3sigma above the average stellar density. The size distribution of the detected clusters can be very well approximated by a Gaussian with a peak at ~ 68 pc. Their cluster mass function is fitted very well by a power-law with index alpha ~ 1.5 +/- 0.7, consistent with other Local Group galaxies and the cluster initial mass function. The application of the nearest-neighbor density method for various density thresholds, other than 3sigma, enabled the identification of stellar concentrations in various length-scales. The stellar density maps constructed with this technique provide a direct proof of hierarchically structured stellar concentrations in NGC 6822. We illustrate this hierarchy by the so-called "dendrogram" of the detected stellar structures, which demonstrates that most of the detected structures split up into several substructures over at least three levels. We quantify the hierarchy of these structures with the use of the minimum spanning tree method. The morphological hierarchy in stellar clustering, which we observe in NGC 6822 resembles that of the turbulent interstellar matter, suggesting that turbulence on pc- and kpc-scales has been probably the major agent that regulated clustered star formation in NGC 6822.Comment: 18 pages in ApJ two-column format, 13 figure

    Waist circumference percentiles for Hispanic-American children and comparison with other international references

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    Introduction Waist circumference (WC) constitutes an indirect measurement of central obesity in children and adolescents. Objective To provide percentiles of WC for Hispanic-American children and adolescents, and compare them with other international references. Materials and methods The sample comprised 13 289 healthy children between 6 and 18 years coming from public schools of middle and low socioeconomic levels in different parts of Argentina, Cuba, Spain, Mexico, and Venezuela. The LMS method to calculate WC percentiles was applied. Sex and age differences were assessed using Student'sttest and ANOVA (SPSS v.21.0). Comparisons were established with references from the United States, Colombia, India, China, Australia, Kuwait, Germany, Tunisia, Greece, and Portugal. Results WC increases with age in both sexes. Boys show higher WC in P3, P50, and P97. Comparison of 50th and 90th percentiles among populations from diverse sociocultural and geographical contexts shows high variability, not all justified by the measurement method. Discussion and conclusions Specific WC percentiles for sex and age, and P90 cut-off points are provided; these values are potentially useful to assess central obesity in Hispanic-American adolescent children
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