123 research outputs found
Spin reorientation transition of magnetite (001)
We have imaged the rearrangement of the magnetic domains on magnetite (001) when crossing the spin reorientation transition and the Verwey transition with nanometer resolution. By means of spin-polarized low-energy electron microscopy we have monitored the change in the easy axes lowering the temperature through both transitions in remanence. The spin reorientation transition occurs in two steps: initial nucleation and growth of domains with a new surface magnetic orientation is followed by a smooth evolution.We thank Dr. A. T. N'Diaye for his support with the scripts for the color representation of the magnetization. This research was partly supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under Projects No. MAT2011-52477-C5-2-P, No. MAT2012-38045-C04-01, and No. MAT2015-64110-C2-1-P. G.S.P. and R.B. acknowledge funding from the Austrian Science Fund START prize Y 847-N20 and Project No. P24925-N20. Experiments were performed at the Molecular Foundry, Lawrence Berkeley National Laboratory, supported by the Office of Science, Office of Basic Energy Sciences, Scientific User Facilities Division, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231. L.M.-G. thanks the MINECO for an FPI contract with reference Contract No. BES-2013-063396. R.B. acknowledges a stipend from the TU Wien and Austrian Science Fund doctoral college Solids4Fun (Project No. W1243). A.M. thanks the support of the Spanish Ministry of Education through Project No. PRX14/00307.Peer Reviewe
ANÁLISIS DEL CICLO DE VIDA PARA LA PRODUCCIÓN DE BIODIESEL A BASE DE ACEITE DE HIGUERILLA EMPLEANDO LA METODOLOGÍA “DE LA CUNA A LA CUNA” ESCENARIO SABANA DE TORRES, SANTANDER
RESUMEN En el presente estudio se aplica la metodología Análisis de Ciclo de Vida (ACV) con el enfoque denominado “de la cuna a la cuna” a la producción de Biodiesel de higuerilla con el objetivo de identificar las etapas del ciclo de vida que afectan más al medio ambiente y elaborar el respectivo perfil ambiental. El enfoque “de la cuna a la cuna” permitió conocer el tiempo necesario de recuperación del terreno, considerando que un porcentaje de los residuos vertidos al medio ambiente, son fijados en la naturaleza gracias a los diferentes ciclos biogeoquímicos. Las etapas contempladas en el ACV son: cultivo e integración de los ciclos biogeoquímicos, extracción del aceite, trasformaciones industriales, uso y disposición de residuos. Se estudiaron las siguientes categorías de impacto: Cambio climático, acidificación, eutrofización, formación de oxidantes fotoquímicos, efectos respiratorios y energía no renovable, identificando las etapas relevantes relacionadas al consumo de energía y emisiones al medio ambiente. Palabras claves: ACV, biocombustibles, emisiones, impacto ambiental. ABSTRACT In this study we work with the Life Cycle Assessment (LCA),is applied with the approach known as “from the cradle to the cradle” to the production of biodiesel from castor oil the objective with of to identify the phases of the life cycle which more affect the environment and make the respective environmental profile.” From the cradle to the cradle” allowed us to know the necessary time of recovery of terrain, considering that one percentage of the discharges residues to the environment are fixed by the nature thank to the different biogeochemical cycles. The phases of the life cycle assessment (LCA) are: cultivation and integration of the cycles biogeochemical, oil extraction, the industrial transformation, the use as biofuel and the residue disposal. The categories of impact studied were: change climatic, acidification, eutrophication, photochemical smog formation, respiratory effects and non-renewable energy, identifying relevant phases related with the consumption energy and emissions to the environment. Keywords: LCA, biofuel, emissions, environmental impac
ANÁLISIS DEL CICLO DE VIDA PARA LA PRODUCCIÓN DE BIODIESEL A BASE DE ACEITE DE HIGUERILLA EMPLEANDO LA METODOLOGÍA “DE LA CUNA A LA CUNA” ESCENARIO SABANA DE TORRES, SANTANDER
RESUMEN En el presente estudio se aplica la metodología Análisis de Ciclo de Vida (ACV) con el enfoque denominado “de la cuna a la cuna” a la producción de Biodiesel de higuerilla con el objetivo de identificar las etapas del ciclo de vida que afectan más al medio ambiente y elaborar el respectivo perfil ambiental. El enfoque “de la cuna a la cuna” permitió conocer el tiempo necesario de recuperación del terreno, considerando que un porcentaje de los residuos vertidos al medio ambiente, son fijados en la naturaleza gracias a los diferentes ciclos biogeoquímicos. Las etapas contempladas en el ACV son: cultivo e integración de los ciclos biogeoquímicos, extracción del aceite, trasformaciones industriales, uso y disposición de residuos. Se estudiaron las siguientes categorías de impacto: Cambio climático, acidificación, eutrofización, formación de oxidantes fotoquímicos, efectos respiratorios y energía no renovable, identificando las etapas relevantes relacionadas al consumo de energía y emisiones al medio ambiente. Palabras claves: ACV, biocombustibles, emisiones, impacto ambiental. ABSTRACT In this study we work with the Life Cycle Assessment (LCA),is applied with the approach known as “from the cradle to the cradle” to the production of biodiesel from castor oil the objective with of to identify the phases of the life cycle which more affect the environment and make the respective environmental profile.” From the cradle to the cradle” allowed us to know the necessary time of recovery of terrain, considering that one percentage of the discharges residues to the environment are fixed by the nature thank to the different biogeochemical cycles. The phases of the life cycle assessment (LCA) are: cultivation and integration of the cycles biogeochemical, oil extraction, the industrial transformation, the use as biofuel and the residue disposal. The categories of impact studied were: change climatic, acidification, eutrophication, photochemical smog formation, respiratory effects and non-renewable energy, identifying relevant phases related with the consumption energy and emissions to the environment. Keywords: LCA, biofuel, emissions, environmental impac
DETERMINACIÓN DE GÉNEROS BACTERIANOS EN EL MAR DE LA PLAYA CANTOLAO – LA PUNTA – CALLAO
Los océanos albergan una gran diversidad biológica, hasta el momento relativamente poco explorada por el humano. Con el objetivo de ampliar los conocimientos en la biodiversidad bacteriana del mar peruano, se realizaron muestreos aleatorios en el mar de Playa Cantolao-La Punta-Callao (12º04´06´´ S 77º10´10´´O), en total se tomaron 5 muestras en frascos estériles a una profundidad de 3 m utilizando una vara de madera acondicionada a una jeringa de 20 ml. Para el aislamiento se utilizó el método de dispersión en placa en Agar Marino, se trabajó con diluciones sucesivas para obtener colonias aisladas. Para la identificación se realizaron pruebas bioquímicas que incluían determinación de citocromo oxidasa, motilidad, producción de H2S, producción de indol, metabolismo de glucosa, producción de pigmento, luminiscencia, catalasa y desarrollo en anaerobiosis; además de las coloraciones Gram y de espora. Los esquemas propuestos por Das S et al. (2007), Oliver J (1982) y el Bergey´s Manual 2da y 7ma edición fueron utilizados para la determinación de géneros. Se logró el aislamiento de 20 cepas bacterianas. Los géneros encontrados fueron: Moraxella, Bacillus, Acinetobacter, Vibrio, Aeromonas, Photobacterium, Alteromonas, Alcaligenes, Streptococcus y Chromobacterium. 
Population Structure in the Model Grass Brachypodium distachyon Is Highly Correlated with Flowering Differences across Broad Geographic Areas
The small, annual grass Brachypodium distachyon (L.) Beauv., a close relative of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), is a powerful model system for cereals and bioenergy grasses. Genome-wide association studies (GWAS) of natural variation can elucidate the genetic basis of complex traits but have been so far limited in B. distachyon by the lack of large numbers of well-characterized and sufficiently diverse accessions. Here, we report on genotyping-by-sequencing (GBS) of 84 B. distachyon, seven B. hybridum, and three B. stacei accessions with diverse geographic origins including Albania, Armenia, Georgia, Italy, Spain, and Turkey. Over 90,000 high-quality single-nucleotide polymorphisms (SNPs) distributed across the Bd21 reference genome were identified. Our results confirm the hybrid nature of the B. hybridum genome, which appears as a mosaic of B. distachyon-like and B. stacei-like sequences. Analysis of more than 50,000 SNPs for the B. distachyon accessions revealed three distinct, genetically defined populations. Surprisingly, these genomic profiles are associated with differences in flowering time rather than with broad geographic origin. High levels of differentiation in loci associated with floral development support the differences in flowering phenology between B. distachyon populations. Genome-wide association studies combining genotypic and phenotypic data also suggest the presence of one or more photoperiodism, circadian clock, and vernalization genes in loci associated with flowering time variation within B. distachyon populations. Our characterization elucidates genes underlying population differences, expands the germplasm resources available for Brachypodium, and illustrates the feasibility and limitations of GWAS in this model grass
Comparison of different methods for delayed post-mortem diagnosis of falciparum malaria
<p>Abstract</p> <p>Background</p> <p>Between 10,000 and 12,000 cases of imported malaria are notified in the European Union each year. Despite an excellent health care system, fatalities do occur. In case of advanced autolysis, the post-mortem diagnostic is impaired. Quicker diagnosis could be achieved by using rapid diagnostic malaria tests.</p> <p>Methods</p> <p>In order to evaluate different methods for the post-mortem diagnosis of <it>Plasmodium falciparum </it>malaria in non-immunes, a study was performed on the basis of forensic autopsies of corpses examined at variable intervals after death in five cases of fatal malaria (with an interval of four hours to five days), and in 20 cases of deaths unrelated to malaria. Detection of parasite DNA by PCR and an immunochromatographic test (ICT) based upon the detection of <it>P. falciparum </it>histidine-rich protein 2 (PfHRP2) were compared with the results of microscopic examination of smears from cadaveric blood, histopathological findings, and autopsy results.</p> <p>Results</p> <p>In all cases of fatal malaria, post-mortem findings were unsuspicious for the final diagnosis, and autoptic investigations, including histopathology, were only performed because of additional information by police officers and neighbours. Macroscopic findings during autopsy were unspecific. Histopathology confirmed sequestration of erythrocytes and pigment in macrophages in most organs in four patients (not evaluable in one patient due to autolysis). Microscopy of cadaveric blood smears revealed remnants of intraerythrocytic parasites, and was compromised or impossible due to autolysis in two cases. PCR and ICT performed with cadaveric blood were positive in all malaria patients and negative in all controls.</p> <p>Conclusion</p> <p>In non-immune fatalities with unclear anamnesis, ICT can be recommended as a sensitive and specific tool for post-mortem malaria diagnosis, which is easier and faster than microscopy, and also applicable when microscopic examination is impossible due to autolysis. PCR is more expensive and time-consuming, but may be used as confirmatory test. In highly endemic areas where asymptomatic parasitaemia is common, confirmation of the diagnosis of malaria as the cause of death has to rely on histopathological findings.</p
European registry on helicobacter pylori management: Effectiveness of first and second-line treatment in Spain
The management of Helicobacter pylori infection has to rely on previous local effectiveness due to the geographical variability of antibiotic resistance. The aim of this study was to evaluate the effectiveness of first and second-line H. pylori treatment in Spain, where the empirical prescription is recommended. A multicentre prospective non-interventional registry of the clinical practice of European gastroenterologists concerning H. pylori infection (Hp-EuReg) was developed, including patients from 2013 until June 2019. Effectiveness was evaluated descriptively and through a multivariate analysis concerning age, gender, presence of ulcer, proton-pump in-hibitor (PPI) dose, therapy duration and compliance. Overall, 53 Spanish hospitals were included, and 10, 267 patients received a first-line therapy. The best results were obtained with the 10-day bismuth single-capsule therapy (95% cure rate by intention-to-treat) and with both the 14-day bismuth-clarithromycin quadruple (PPI-bismuth-clarithromycin-amoxicillin, 91%) and the 14-day non-bismuth quadruple concomitant (PPI-clarithromycin-amoxicillin-metronidazole, 92%) therapies. Second-line therapies were prescribed to 2448 patients, with most-effective therapies being the triple quinolone (PPI-amoxicillin-levofloxacin/moxifloxacin) and the bismuth-levofloxacin quadruple schemes (PPI-bismuth-levofloxacin-amoxicillin) prescribed for 14 days (92%, 89% and 90% effective-ness, respectively), and the bismuth single-capsule (10 days, 88.5%). Compliance, longer duration and higher acid inhibition were associated with higher effectiveness. “Optimized” H. pylori therapies achieve over 90% success in Spain
Estudio de inmunogenicidad para dos vacunas recombinantes contra hepatitis B
This study compares the immunogenicity (seroconversion, seroprotection and hiperesponse) produced by two hepatitis B recombinant vaccines (Engerix- B Belge and Cuban). For this purpose two sketches were used (012 and 016 months). The anti-HBs quantification was performed by using Abbott and Organon methods in order to compare its results. In the study 257 volunteers were distributed in four groups to the hapazard (two vaccines and two sketches). Results: the Abbott and Organon methods did not show any statistically significant difference. The Cuban vaccine shows greater immunogenous response for two doses and 012 sketch. There are no differences between sketch 012 and 016 with the Cuban vaccine. The scheme 016 did not show statistically significant difference for the Engerix-B Belge vaccine. The last mentioned vaccine showed to be better with the 016 scheme.Este estudio compara la inmunogenicidad (seroconversión, seroprotección e Hiperrespuesta), producida por dos vacunas recombinantes contra la hepatitis B (Engerix-B de Bélgica y Cubana), en dos esquemas (012 y 016 meses), empleando los métodos de cuantificación para Anti-HBsAg (Abbott y Organón), los cuales fueron también comparados. En el estudio participaron 257 voluntarios, divididos al azar en 4 grupos (dos vacunas, dos esquemas). Resultados: los dos métodos de Abbon y Organon, no presentan diferencias estadísticas significativas. La vacuna cubana muestra una mayor respuesta inmunogénica para dos dosis de vacuna y para el esquema 012. No hay diferencia entre los esquemas 012 y 016 y en el esquema 016 no se ven diferencias estadísticamente significativas con la vacuna Engerix-B. En esta Última el esquema 016 muestra mejores resultados que el 012
Expression patterns of Passiflora edulis APETALA1/FRUITFULL homologues shed light onto tendril and corona identities
Competitividade relativa entre cultivares de arroz irrigado e biótipo de arroz-vermelho
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