536 research outputs found

    The Mazarrón basin, SE Spain: a study of mineralization processes, evolving magmatic series, and geothermal activity

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    The Miocene to Present Mazarrón basin provides a window on the metallogenic role of an evolving magmatic series. High-K calc–alkaline magmas gave rise to an important cluster of Pb–Zn–Ag–Cu vein and stockwork deposits emplaced in dacitic to rhyodacitic domes, part of a complex volcanic–metallogenic province (Au, Hg, Pb–Zn–Cu–Ag, Sn) stretching for ∼150 km along the Mediterranean coast of SE Spain. By Pliocene time the former magmatic series had been replaced by intraplate alkaline basaltic volcanism, thus becoming the southern branch of the Western/Central Europe alkaline province. In terms of base metal sulphide deposits, this European province is barren, although it triggered widespread, CO2-rich geothermal activity. Modern geothermal activity at El Saladillo (Mazarrón) resulted in the deposition of carbonate sinter deposits and formation of microbial mats. Proximal facies consist of millimetric to centimetric multicoloured layers of microbial mats, including yellow-orange thin bands of calcified bacteria and mineral growths of aragonite and calcite; green layers of live thermophilic Lyngbya-type cyanobacteria; black, degraded organic matter; and pyrite as the sole sulphide phase. Except for arsenic (37–63 μg g−1), all of the studied trace elements (Ag, Ba, Bi, Cd, Cu, Pb, Sb, Se, and Sn) appear in remarkably low concentrations in the geothermal sinters. This is consistent with compositional data for the El Saladillo waters, with no significant metal concentrations. We present the first conceptual model (Miocene to Present) for the ore-forming processes, magmatism, CO2 degasification, and geothermal activity for this realm. We argue that the time- and space-limited character of this volcanism (small, scattered outcrops), the deep magma emplacement level, the metal sulphide behaviour in alkaline basaltic magmatic chambers, and the dry character of these magmas prevented any metallogenic interaction between the chambers and the much shallower meteoric waters that drove the El Saladillo geothermal system and others of the same kind in Spain and elsewhere in Europe

    Low friction along the high slip patch of the 2011 Mw 9.0 Tohoku-Oki earthquake required from the wedge structure and extensional splay faults

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    We analyze the mechanical properties needed to account for the large shallow slip during the 2011 Tohoku-Oki earthquake and the activation of landward normal faulting within the forearc. We show that the morphology and internal structure of the forearc follows closely the prediction of the critical Coulomb wedge in horizontal compression, implying a high internal pore pressure ratio (λ = 0.7 + 0.14/ – 0.48) and a low effective basal friction (μ^(eff)_b = 0.14 + 0.18/ – 0.04). We then show that the activation of the normal fault requires a lower effective basal friction beneath the outer wedge than beneath the inner wedge (μ_outer ≤ 0.015), possibly due to transient dynamic weakening associated to the seismic rupture. Forearc normal faults could be considered as evidence for very efficient dynamic weakening along the megathrust and typify megathrust with high tsunamigenic potential

    Influencia del porcentaje de adición de quinua (Chenopodium quinoa), piña (Ananas comosus L. Merr) y nivel de dilución en la fortificación del néctar de manzana (Malus domestica) sobre la calidad del producto

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    El objetivo del presente trabajo fue evaluar la influencia del porcentaje de adición de quinua (Chenopodium quinoa), piña (Ananas comosus L. Merr) y nivel de dilución en la fortificación del néctar de manzana (Malus domestica) sobre la calidad del producto. Se utilizó piña de la variedad roja Trujillana con un pH de 3,38 y 65,04 mg de vitamina C/100 ml y quinua blanca con 14,44% de proteína y 1,69% de fibra. Los porcentajes de piña-quinua utilizados para la elaboración del néctar fueron: tratamiento 1 (20-10%), 2 (15-15) y 3 (10-20) y los niveles de dilución fueron: tratamiento 1(1:3), 2 (1:3.5) y 3(1:4). Se evaluaron mediante tres niveles (11, 12, 13, 21, 22, 23, 31, 32, 33), con un total de 9 tratamientos. Los resultados de la evaluación fisicoquímica °Brix, pH y acidez titulable mediante un análisis de varianza y la prueba Tukey al 5% así como la evaluación sensorial para evaluar la preferencia del néctar mediante escala hedónica de 5 puntos mostraron como mejor tratamiento proporción piña – quinua 15-15 % y nivel de dilución 1:3 (tratamiento 21) con 12,5°Brix; 0,47% de acidez titulable; 4,0 de pH; 1,17 % de proteína; 0,37% de grasa; 0,63% de fibra y el contenido de vitamina C fue 8,91 mg/100 ml de néctar. En conclusión, la influencia de la adición de piña-quinua y nivel de dilución en la fortificación del néctar de manzana se vio reflejada principalmente por el contenido de vitamina C, proteínas y fibra en el producto final

    EXAME REPRODUTIVO EM GATO-DO-MATO-PEQUENO (Leopardus tigrinus Schreber, 1775)

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    A better understanding of the reproductive physiology of Neotropical small felids is necessary to get a more consistent reproductive performance aiming to increase the number of individuals that reproduce in the captive population and to develop and use assisted reproduction techniques. Andrologic examinations (n=32) were performed in three series of captive small catamounts (Leopardus tigrinus, n=11), at Itaipu Binacional Wildlife Breeding Center, at Foz do Iguassu PR Brazil. Animals were kept in enriched enclosures and were fed with bovine meat, whole chicken, rats, supplemented with minerals and vitamins. The anesthetic protocol used was xilazine (0.9 mg/kg, IM) combined with tiletamine/zolazepan (6.7 mg/kg, IM). The electroejaculation protocol used was described by Howard (1986) and consisted in 8 series of 10 stimulus, with intensity varying from 2 to 5 volts. Urine contamination was detected in 10 semen samples (31.2%), being possible to discard these and make good use of the other ones. Values are depicted as mean ± SEM. The characteristics of the semen were: volume 0.13 ± 0.20 ml; motility 73.44 ± 3.71%; status 3.48 ± 0.11; pH 7.58 ± 0.07. Spermatic concentration was 436.41 ± 95.8 x 106 cells/ml, with 55.86 ± 3.34 % morphologically normal spermatozoids. Results demonstrated that the used protocol was efficient in all animals submitted to semen collection and that teratospermia is high in this species.O objetivo desta pesquisa foi obter melhor compreensão da fisiologia reprodutiva dos pequenos felídeos neotropicais, necessária para um desempenho reprodutivo mais consistente em cativeiro e aumentar o número de indivíduos que se reproduzem na população cativa. Foram realizadas três séries de exames reprodutivos (n=32) em 11 gatos-do-mato-pequeno (Leopardus tigrinus), mantidos em cativeiro no Criadouro de Animais Silvestres da Itaipu Binacional, em Foz do Iguaçu PR. Os animais estavam alojados em recintos ambientados e eram alimentados com carne bovina, frango, pintainhos, ratos e suplemento mineral/vitamínico. O protocolo anestésico utilizado foi a associação de cloridrato de xilazina e cloridrato de tiletamina/zolazepan nas doses médias de 0,95 mg/Kg e 6,7 mg/kg, respectivamente. Os animais foram submetidos à colheita de sêmen pelo método de eletroejaculação conforme protocolo descrito por HOWARD (1986) com 8 séries de 10 estímulos, variando a intensidade de 2 a 5 Volts. Houve contaminação por urina em 10 colheitas (31,2%), sendo possível desprezar as alíquotas contaminadas, com aproveitamento do restante da amostra. O volume médio obtido foi de 0,13 ± 0,20 ml, com motilidade média de 73,44 ± 3,71 % e vigor de 3,48 ± 0,11 . O pH médio foi 7,58 ± 0,07. A concentração espermática foi de 436,41 ± 95,8 x 106 espermatozóides/ml, sendo que a porcentagem média de espermatozóides morfologicamente normais foi de 55,86 ± 3,34 %. Os valores obtidos nesta amostragem são compatíveis com os descritos por outros autores, contribuindo assim, na formação de um banco de dados de características reprodutivas, para felídeos desta espécie mantidos em cativeiro

    La compatibilidad entre estudios y deporte en estudiantes de secundaria

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    The purpose of this research was to analysethe difficulties thathigh school studentshadto balance outstudiesandsports. Following adescriptiveexploratorymethodandthroughthe application of atestquestionnaireandconductinga discussion group, informationwascollectedin relation to fourkey factors: the characteristicsof the sport, the conflicts of interestemergedinbalancingstudiesand sport, the support and resources theyhadto bring togetherthisdoubleactivityandthetrainingand professional expectationsthatwereahead of theirfuture. Theanalysis of the differentfactors involved inthe development of thisdouble activity, constitutes afundamentalelement of reference sothatschoolsimplementmeasuresand actions that allow these students to continue with theirsports training, without having to give upeducation. The results obtainedhighlightthe difficulties thathigh school students havetocombineboth processes, which requires them greateffort, good planning ofgoals, appropriate organization of time andpersistenceinachievingthe objectives.La finalidad de esta investigación fue analizar las dificultades que los estudiantes de secundaria tenían para compatibilizar estudios y deportes. Siguiendo un método descriptivo de carácter exploratorio y a través de la aplicación de una prueba de cuestionario y la realización de un grupo de discusión, se recogió información en relación a cuatro factores clave: las características propias de la práctica deportiva, el conflicto de intereses surgido a la hora de compatibilizar los estudios y el deporte, los apoyos y recursos con los que contaban para armonizar esta doble actividad y las expectativas formativas y profesionales que tenían de cara a su futuro. El análisis de los distintos factores que intervienen en el desarrollo de esta doble actividad, constituye un elemento de referencia fundamental para que los centros educativos implanten medidas y acciones que permitan a estos estudiantes continuar con su preparación deportiva, sin tener que renunciar a la formación. Los resultados obtenidos ponen de manifiesto las dificultades que tienen los estudiantes de secundaria para compaginar ambos procesos, lo que les exige un gran esfuerzo, una buena planificación de metas, una adecuada organización del tiempo y persistencia en el logro de los objetivos planteados

    Plant-RRBS, a bisulfite and next-generation sequencing-based methylome profiling method enriching for coverage of cytosine positions

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    Background: Cytosine methylation in plant genomes is important for the regulation of gene transcription and transposon activity. Genome-wide methylomes are studied upon mutation of the DNA methyltransferases, adaptation to environmental stresses or during development. However, from basic biology to breeding programs, there is a need to monitor multiple samples to determine transgenerational methylation inheritance or differential cytosine methylation. Methylome data obtained by sodium hydrogen sulfite (bisulfite)-conversion and next-generation sequencing (NGS) provide genome- wide information on cytosine methylation. However, a profiling method that detects cytosine methylation state dispersed over the genome would allow high-throughput analysis of multiple plant samples with distinct epigenetic signatures. We use specific restriction endonucleases to enrich for cytosine coverage in a bisulfite and NGS-based profiling method, which was compared to whole-genome bisulfite sequencing of the same plant material. Methods: We established an effective methylome profiling method in plants, termed plant-reduced representation bisulfite sequencing (plant-RRBS), using optimized double restriction endonuclease digestion, fragment end repair, adapter ligation, followed by bisulfite conversion, PCR amplification and NGS. We report a performant laboratory protocol and a straightforward bioinformatics data analysis pipeline for plant-RRBS, applicable for any reference-sequenced plant species. Results: As a proof of concept, methylome profiling was performed using an Oryza sativa ssp. indica pure breeding line and a derived epigenetically altered line (epiline). Plant-RRBS detects methylation levels at tens of millions of cytosine positions deduced from bisulfite conversion in multiple samples. To evaluate the method, the coverage of cytosine positions, the intra-line similarity and the differential cytosine methylation levels between the pure breeding line and the epiline were determined. Plant-RRBS reproducibly covers commonly up to one fourth of the cytosine positions in the rice genome when using MspI-DpnII within a group of five biological replicates of a line. The method predominantly detects cytosine methylation in putative promoter regions and not-annotated regions in rice. Conclusions: Plant-RRBS offers high-throughput and broad, genome- dispersed methylation detection by effective read number generation obtained from reproducibly covered genome fractions using optimized endonuclease combinations, facilitating comparative analyses of multi-sample studies for cytosine methylation and transgenerational stability in experimental material and plant breeding populations

    Errors in the bisulfite conversion of DNA: modulating inappropriate- and failed-conversion frequencies

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    Bisulfite treatment can be used to ascertain the methylation states of individual cytosines in DNA. Ideally, bisulfite treatment deaminates unmethylated cytosines to uracils, and leaves 5-methylcytosines unchanged. Two types of bisulfite-conversion error occur: inappropriate conversion of 5-methylcytosine to thymine, and failure to convert unmethylated cytosine to uracil. Conventional bisulfite treatment requires hours of exposure to low-molarity, low-temperature bisulfite (‘LowMT’) and, sometimes, thermal denaturation. An alternate, high-molarity, high-temperature (‘HighMT’) protocol has been reported to accelerate conversion and to reduce inappropriate conversion. We used molecular encoding to obtain validated, individual-molecule data on failed- and inappropriate-conversion frequencies for LowMT and HighMT treatments of both single-stranded and hairpin-linked oligonucleotides. After accounting for bisulfite-independent error, we found that: (i) inappropriate-conversion events accrue predominantly on molecules exposed to bisulfite after they have attained complete or near-complete conversion; (ii) the HighMT treatment is preferable because it yields greater homogeneity among sites and among molecules in conversion rates, and thus yields more reliable data; (iii) different durations of bisulfite treatment will yield data appropriate to address different experimental questions; and (iv) conversion errors can be used to assess the validity of methylation data collected without the benefit of molecular encoding
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