Reseñas iberoamericanas

Iberoamerican reviewsReseñas iberoamericana

Reseñas iberoamericanas

Reseñas iberoamericana

Huanuni, Bonanza and La Suerte Mines: mineralogy, geochemistry and structure

The polymetallic mineralization veins of the world class Huanuni district in Bolivia form a conspicuously intricate framework. Comprehensive study on the mineralogy of proximal and distal deposits indicates that In is preferably concentrated in sphalerite precipitated in a lower-temperature stage in the distal domain. Other strategic elements reported to concentrate in equivalent deposits (e.g. Ga, Ge, Nb, Ta), though, returned very low or no detectable concentrations. Mineral paragenesis and textures and sulfur isotopic data support a complex mineralization history that probably implied multi-episodic intrusive events.Peer ReviewedPostprint (published version

Huanuni, Bonanza and La Suerte Mines: mineralogy, geochemistry and structure

The polymetallic mineralization veins of the world class Huanuni district in Bolivia form a conspicuously intricate framework. Comprehensive study on the mineralogy of proximal and distal deposits indicates that In is preferably concentrated in sphalerite precipitated in a lower-temperature stage in the distal domain. Other strategic elements reported to concentrate in equivalent deposits (e.g. Ga, Ge, Nb, Ta), though, returned very low or no detectable concentrations. Mineral paragenesis and textures and sulfur isotopic data support a complex mineralization history that probably implied multi-episodic intrusive events.Peer Reviewe

Huanuni, Bonanza and La Suerte Mines: mineralogy, geochemistry and structure

The polymetallic mineralization veins of the world class Huanuni district in Bolivia form a conspicuously intricate framework. Comprehensive study on the mineralogy of proximal and distal deposits indicates that In is preferably concentrated in sphalerite precipitated in a lower-temperature stage in the distal domain. Other strategic elements reported to concentrate in equivalent deposits (e.g. Ga, Ge, Nb, Ta), though, returned very low or no detectable concentrations. Mineral paragenesis and textures and sulfur isotopic data support a complex mineralization history that probably implied multi-episodic intrusive events.Peer Reviewe

Mineralogy and distribution of critical elements in the Sn–W–Pb–Ag–Zn Huanuni deposit, Bolivia

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for d34SVCDT values, which range -7.2‰ to 0.2‰ (mostly -7‰ to -5‰) in the central area and -4.2‰ to 1.0‰ (mainly constrained between -2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areasPeer Reviewe

Effects of tubulin acetylation and tubulin acetyltransferase binding on microtubule structure

Tubulin undergoes posttranslational modifications proposed to specify microtubule subpopulations for particular functions. Most of these modifications occur on the C-termini of tubulin and may directly affect the binding of microtubule-associated proteins (MAPs) or motors. Acetylation of Lys-40 on α-tubulin is unique in that it is located on the luminal surface of microtubules, away from the interaction sites of most MAPs and motors. We investigate whether acetylation alters the architecture of microtubules or the conformation of tubulin, using cryo–electron microscopy (cryo-EM). No significant changes are observed based on protofilament distributions or microtubule helical lattice parameters. Furthermore, no clear differences in tubulin structure are detected between cryo-EM reconstructions of maximally deacetylated or acetylated microtubules. Our results indicate that the effect of acetylation must be highly localized and affect interaction with proteins that bind directly to the lumen of the microtubule. We also investigate the interaction of the tubulin acetyltransferase, αTAT1, with microtubules and find that αTAT1 is able to interact with the outside of the microtubule, at least partly through the tubulin C-termini. Binding to the outside surface of the microtubule could facilitate access of αTAT1 to its luminal site of action if microtubules undergo lateral opening between protofilaments

Characteristics, complications and outcomes among 1549 patients hospitalised with COVID-19 in a secondary hospital in Madrid, Spain: a retrospective case series study

Objectives To describe demographic, clinical, radiological and laboratory characteristics, as well as outcomes, of patients admitted for COVID-19 in a secondary hospital.Design and setting Retrospective case series of sequentially hospitalised patients with confirmed SARS-CoV-2, at Infanta Leonor University Hospital (ILUH) in Madrid, Spain.Participants All patients attended at ILUH testing positive to reverse transcriptase-PCR on nasopharyngeal swabs and diagnosed with COVID-19 between 1 March 2020 and 28 May 2020.Results A total of 1549 COVID-19 cases were included (median age 69 years (IQR 55.0–81.0), 57.5% men). 78.2% had at least one underlying comorbidity, the most frequent was hypertension (55.8%). Most frequent symptoms at presentation were fever (75.3%), cough (65.7%) and dyspnoea (58.1%). 81 (5.8%) patients were admitted to the intensive care unit (ICU) (median age 62 years (IQR 51–71); 74.1% men; median length of stay 9 days (IQR 5–19)) 82.7% of them needed invasive ventilation support. 1393 patients had an outcome at the end of the study period (case fatality ratio: 21.2% (296/1393)). The independent factors associated with fatality (OR; 95% CI): age (1.07; 1.06 to 1.09), male sex (2.86; 1.85 to 4.50), neurological disease (1.93; 1.19 to 3.13), chronic kidney disease (2.83; 1.40 to 5.71) and neoplasia (4.29; 2.40 to 7.67). The percentage of hospital beds occupied with COVID-19 almost doubled (702/361), with the number of patients in ICU quadrupling its capacity (32/8). Median length of stay was 9 days (IQR 6–14).Conclusions This study provides clinical characteristics, complications and outcomes of patients with COVID-19 admitted to a European secondary hospital. Fatal outcomes were similar to those reported by hospitals with a higher level of complexity

The Social Anxiety Questionnaire for Children: Cross-Cultural Assessment with a New Self-Report Measure

This study describes a series of exploratory and confirmatory factor analyses that were conducted with the 44-item Social Anxiety Questionnaire for Children- 4th version (SAQ-CIV) to identify a reduced set of items that might be used to construct a new abbreviated instrument for measuring social anxiety in children and adolescents. The fourth version of the Social Anxiety Questionnaire for Children (SAQ-CIV) was administered to 12,801 non-clinical participants (ages 9 to 15 years) from 12 Latin American countries and Spain. Exploratory and confirmatory factor analysis supported a 6-factor structure of social anxiety in children, replicating a similar structure to that of adults (Caballo et al. in Behavioral Psychology/Psicología Conductual, 18(1), 5–34, 2010; Caballo et al. in Behavior Therapy, 43(2), 313–328, 2012): 1) Interactions with the opposite sex, 2) Criticism and embarrassment, 3) Speaking in public/Talking to teachers, 4) Assertive expression of annoyance and disgust, 5) Performing in public, and 6) Interactions with strangers. Each of the factors contains 4 items, yielding an abbreviated 24-item instrument, the Social Anxiety Questionnaire for Children (SAQ-C). The present results suggest this is a reliable, valid, and culturally sensitive instrument to assess social anxiety in youth