Measurements of absolute K -shell ionization cross sections and L -shell x-ray production cross sections of Ge by electron impact

Results from measurements of absolute K -shell ionization cross sections and L α x-ray production cross sections of Ge by impact of electrons with kinetic energies ranging from the ionization threshold up to 40 keV are presented. The cross sections were obtained by measuring K α and L α x-ray intensities emitted from ultrathin Ge films deposited onto self-supporting carbon backing films. Recorded x-ray intensities were converted to absolute cross sections by using estimated values of the sample thicknesses, the number of incident electrons, and the detector efficiency. Experimental data are compared with the results of widely used simple analytical formulas, with calculated cross sections obtained from the plane-wave and distorted-wave Born approximations and with experimental data from the literature

Reflexiones sobre la idea de comunicatividad para la clase de español como lengua extranjera en Noruega

Este artículo se concibe como una reflexión acerca de la idea central de comunicatividad en la enseñanza de lenguas extranjeras en la educación reglada noruega. Más concretamente, el objetivo es examinar sucintamente los aspectos clave en la implementación de un enfoque comunicativo en la clase de español como lengua extranjera (ELE). Desde la conjunta investigación en didáctica de lenguas extranjeras en Noruega, se constata que cinco décadas después del inicio del paradigma comunicativo, la enseñanza de lenguas en la escuela secundaria noruega muestra una limitada orientación comunicativa. Uno de los factores que explican este fenómeno es la fuerte influencia que ejercen las creencias de los profesores originadas en su periodo de escolarización por encima de los principios teóricos sobre los que se sustenta la reforma educativa vigente (Kunnskapsløftet-K06). El éxito de la nueva renovación educativa (Fagfornyelsen-K20) radica parcialmente en cómo los programas de desarrollo docente, tanto de manera inicial como continua, vehiculan los principios de la enseñanza comunicativa para que los profesores participen en procesos de reflexión crítica en la articulación de sus creencias. Esta reflexión examina estos principios y sugiere un eventual acercamiento en los programas de formación que facilite el reto al que se enfrentan los estudiantes de relacionar conceptos teóricos con su implementación práctica y la articulación de sus creencias.publishedVersio

Use of the Bethe equation for inner-shell ionization by electron impact

We analyzed calculated cross sections for K-, L-, and M-shell ionization by electron impact to determine the energy ranges over which these cross sections are consistent with the Bethe equation for inner-shell ionization. Our analysis was performed with K-shell ionization cross sections for 26 elements, with L-shell ionization cross sections for seven elements, L-3-subshell ionization cross sections for Xe, and M-shell ionization cross sections for three elements. The validity (or otherwise) of the Bethe equation could be checked with Fano plots based on a linearized form of the Bethe equation. Our Fano plots, which display theoretical cross sections and available measured cross sections, reveal two linear regions as predicted by de Heer and Inokuti [in Electron Impact Ionization, edited by T. D. Mark and G. H. Dunn, (Springer-Verlag, Vienna, 1985), Chap. 7, pp. 232-276]. For each region, we made linear fits and determined values of the two element-specific Bethe parameters. We found systematic variations of these parameters with atomic number for both the low-and the high-energy linear regions of the Fano plots. We also determined the energy ranges over which the Bethe equation can be used

Taxonomic identification of different species of the genus aeromonas by whole-genome sequencing and use of their species-specific Β-lactamases as phylogenetic markers

Altres ajuts: Departament de Microbobiologia de l'Hospital de la Santa Creu i Sant Pau, i l'Institut de Recerca de l'Hospital de la Santa Creu i Sant PauSome Aeromonas species, potentially pathogenic for humans, are known to express up to three different classes of chromosomal Β-lactamases, which may become hyperproduced and cause treatment failure. The aim of this study was to assess the utility of these species-specific Β-lactamase genes as phylogenetic markers using whole-genome sequencing data. Core-genome alignments were generated for 36 Aeromonas genomes from seven different species and scanned for antimicrobial resistance genes. Core-genome alignment confirmed the MALDI-TOF identification of most of the isolates and re-identified an A. hydrophila isolate as A. dhakensis. Three (B, C and D) of the four Ambler classes of Β-lactamase genes were found in A. sobria, A. allosacharophila, A. hydrophila and A. dhakensis (bla, bla and bla). A. veronii only showed class-B- and class-D-like matches (bla and bla), whereas those for A. media, A. rivipollensis and A. caviae were class C and D (bla, bla and bla). The phylogenetic tree derived from concatenated sequences of Β-lactamase genes successfully clustered each species. Some isolates also had resistance to sulfonamides, quinolones and aminoglycosides. Whole-genome sequencing proved to be a useful method to identify Aeromonas at the species level, which led to the unexpected identification of A. dhakensis and A.rivipollensis and revealed the resistome of each isolate

A track record of Au-Ag nanomelt generation during fuid‑mineral interactions

Recent studies have reported the signifcant role of Au-bearing nanoparticles in the formation of hydrothermal gold deposits. Despite the ever-increasing understanding of the genesis and stability of Au-bearing nanoparticles, it is still unknown how they behave when exposed to hydrothermal fuids. Here, we study the nanostructural evolution of Au–Ag nanoparticles hosted within Co-rich diarsenides and sulfarsenides of a natural hydrothermal deposit. We use high-resolution transmission electron microscopy to provide a singular glimpse of the complete melting sequence of Au–Ag nanoparticles exposed to the hydrothermal fuid during coupled dissolution–precipitation reactions of their host minerals. The interaction of Au–Ag nanoparticles with hydrothermal fuids at temperatures (400– 500 ºC) common to most hydrothermal gold deposits may promote melting and generation of Au–Ag nanomelts. This process has important implications in noble metal remobilization and accumulation during the formation of these deposits

Abellaite, NaPb2(CO3)2(OH), a new supergene mineral from the Eureka mine, Lleida province, Catalonia, Spain

The new mineral abellaite (IMA 2014-111), ideally NaPb2 (CO3)2 (OH), is a supergene mineral that was found in one of the galleries of the long-disused Eureka mine, in the southern Pyrenees (Lleida province), Catalonia, Spain. Abellaite is found as sparse coatings on the surface of the primary mineralization, it forms subhedral crystals not larger than 10μm as well as larger pseudohexagonal platelets up to ~ 30μm. Individual crystals commonly have a tabular to lamellar habit and form fairly disordered aggregates. The mineral is associated with a large number of primary minerals (roscoelite, pyrite, uraninite, coffinite, 'carbon', galena, sphalerite, nickeloan cobaltite, covellite, tennantite and chalcopyrite) and supergene minerals (hydrozincite, aragonite, gordaite, As-rich vanadinite andersonite, čejkaite, malachite and devilline). Abellaite is colourless to white, with a vitreous to nacreous lustre. The mineral is translucent, has a white streak and is non-fluorescent. The aggregates of microcrystals are highly friable. The calculated density using the ideal formula is 5.93 g/cm3. The chemical composition of the mineral (the mean of 10 electron microprobe analyses) is Na 3.88, Ca 0.29, Pb 72.03, C 4.17, O 19.47 and H 0.17, total 100.00 wt% (H, C and O by stoichiometry assuming the ideal formula). On the basis of 7 O atoms, the empirical formula of abellaite is Na0.96 Ca0.04 Pb1.98 (CO3)2 (OH). The simplified formula of the mineral is NaPb2 (CO3)2 (OH). The mineral is hexagonal, space group P 63 mc, a = 5.254(2), c = 13.450(5) Å, V = 321.5(2) Å3 and Z = 2. The strongest powder-diffraction lines [d in Å (I) (h k l)] are: 3.193 (100) (0 1 3), 2.627 (84) (1 1 0), 2.275 (29) (0 2 0), 2.242 (65) (0 2 1, 0 0 6), 2.029(95) (0 2 3). Abellaite has a known synthetic analogue, and the crystal structure of the mineral was refined by using crystallographic data of the synthetic phase. The mineral is named in honour of the mineralogist and gemmologist Joan Abella i Creus (b. 1968), who has long studied the deposits of the Eureka mine and who collected the mineral

Time Trends of Crohn's Disease in Catalonia from 2011 to 2017. Increasing Use of Biologics Correlates with a Reduced Need for Surgery

Background and Aims: Data from clinical trials suggest that biological drugs may improve the outcomes in Crohn's disease (CD) by reducing the need for surgery or hospitalization. The aim of this study is to evaluate the time-trends of the use of biological drugs and other treatments for CD, and its relationship with outcomes in Catalonia. Materials and Methods: All patients with CD included in the Catalan Health Surveillance System (containing data on a population of more than 7.5 million) from 2011 to 2017 were identified. The exposures to different treatments for inflammatory bowel disease were retrieved from electronic invoicing records. Results: Between 2011 and 2017, the use of salicylates, corticosteroids and immunosuppressive treatment fell from 28.8% to 17.1%, 15.8% to 13.7%, and 32.9% to 29.6%, respectively (p < 0.001). Biological treatment use rose from 15.0% to 18.7% (p < 0.001). Ostomy rates per 1000 patients/year fell from 13.2 in 2011 to 9.8 in 2017 (p = 0.003), and surgical resection rates from 24.1 to 18.0 (p < 0.001). The rate of CD-related hospitalizations per 1000 patients/year also fell, from 92.7 to 72.2 (p < 0.001). Conclusions: Biological drug use rose from 15.0% to 18.7% between 2011 and 2017. During this period, we observed an improvement in the outcomes of CD patients

Heterogeneity in pharmacological treatment and outcomes in Crohn's disease patients in Catalonia : a population-based observational study

Heterogeneity in the treatment of a disease is a marker of suboptimal quality of care. The aim of this study is to evaluate the heterogeneity in the treatment used and the outcomes for Crohn's disease (CD) in Catalonia. All patients with CD included in the Catalan Health Surveillance System (data on more than seven million individuals from 2011 to 2017) were identified. The different Catalonian health areas were grouped into 19 district groups (DG). Treatments used rates (systemic corticosteroids, non-biological and biological immunosuppressant) and outcomes rates (hospitalization and surgery) were calculated. The use of systemic corticosteroids presented a decreasing trend over the study period, with an average rate of use in the different territories between 11% and 17%. The use of non-biological immunosuppressant treatment has remained stable, with an average rate of use ranging from 22% to 40% per year depending on the DG. The use of biological immunosuppressant treatment increased with an average rate of use in the different territories ranging from 10 to 23%. Hospitalizations for any reason showed an increasing trend between 2011 and 2017 with an average rate of between 23% and 32% per year depending on the area. Hospitalizations for CD presented a decreasing trend, with an average rate of between 5% and 11% per year. Surgical treatment remained stable over time, rates per year were between 0.5% and 2%. A remarkable geographical heterogeneity in the use of different treatments and in outcomes of CD was observed between different geographical areas of Catalonia

Técnicas de caracterización mineral y su aplicación en exploración minera

En este trabajo se presenta una síntesis de las técnicas analíticas más utilizadas en la caracterización mineral, y su aplicación a la exploración y explotación minera. Las técnicas han sido clasificadas en 2 grupos. El primer grupo incluye a las técnicas de mayor uso ("técnicas convencionales"): (i) difracción de polvo de rayos X y difracción cuantitativa de rayos X, (ii) Microscopio electrónico de barrido con analizador de energías (SEM-EDS), (iii) catodoluminiscencia, y iv) microsonda electrónica (EMPA). El segundo grupo abarca un grupo de técnicas menos accesible, y mucho más caras, ("técnicas no convencionales"): (i) Particle Induced X-Ray Emission(Micro-PIXE), (ii) Secondary Ion Mass Spectrometry (SIMS, (iii) Laser-Ablation-Inductively Coupled Plasma-Mass Spectrometry (LAICP-MS). La mayor parte de la compilación esta dedicada a las técnicas convencionales (DRX, SEM-EDS y EMP), las cuales pueden ser de mayor impacto en el campo de la pequeña minerí

Impact of fertilization with pig slurry on the isotopic composition of nitrate retained in soil and leached to groundwater in agricultural areas

The isotopic composition of N and O of nitrate (NO3−) is usually employed to trace its sources of pollution in groundwater. In agricultural areas, the amount of NO3− that reaches the aquifers after fertilization is controlled by different transformation processes that can affect the nitrogen species isotopic composition. Aiming to address the reliability of using isotope tools to trace sources of groundwater NO3−, the goal of this study was to check the effect of fertilization on the isotopic composition of N compounds retained and leached from soils. The concentration and isotopic composition (δ15N and δ18O) of ammonium (NH4+), NO3− and nitrite (NO2−) was characterized after the application of pig slurry in lysimeters containing either soil under fallow (LF) or the same soil continuously cropped and fertilized (LC) during the previous six years. Results showed that the leached NO3− isotopic signature did not directly reflect the isotopic composition of the applied pig slurry. Just after fertilization, nitrification led to lower δ15NNO3 values in soil extracts and leachates (e.g. from +5.9 ± 0.9¿ to +3.8 ± 3.1¿ in soil extracts of LF lysimeters). These values increased after complete nitrification (+11.5 ± 1.3¿) towards the δ15Nbulk of pig slurry (+19.6 ± 0.5¿). Later on, due to soil organic matter and plant debris mineralization and subsequent nitrification, values decreased towards the initial δ15NNO3 of soil but remained above them (+8.6 ± 1.0¿). Both LF and LC experiments showed a similar trend and the latter ones allowed to reinforce that long-term fertilization with pig slurry can increase the soil δ15NNO3. Concerning the δ18O of NO3− from soil extracts and leachates, it mainly depended on the δ18O of irrigation water and oxygen, after nitrification of NH4+ from pig slurry. Therefore, studies aiming to trace groundwater NO3− pollution sources in rural areas by using an isotopic approach should consider the fertilization history of each setting. Also, analyzing the δ15Nbulk of soil is recommended, since it could mask the isotopic signature of the N applied through fertilization