Biosynthesis of CdS Quantum Dots Mediated by Volatile Sulfur Compounds Released by Antarctic Pseudomonas fragi

Previously we reported the biosynthesis of intracellular cadmium sulfide quantum dots (CdS QDs) at low temperatures by the Antarctic strain Pseudomonas fragi GC01. Here we studied the role of volatile sulfur compounds (VSCs) in the biosynthesis of CdS QDs by P. fragi GC01. The biosynthesis of nanoparticles was evaluated in the presence of sulfate, sulfite, thiosulfate, sulfide, cysteine and methionine as sole sulfur sources. Intracellular biosynthesis occurred with all sulfur sources tested. However, extracellular biosynthesis was observed only in cultures amended with cysteine (Cys) and methionine (Met). Extracellular nanoparticles were characterized by dynamic light scattering, absorption and emission spectra, energy dispersive X-ray, atomic force microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Purified QDs correspond to cubic nanocrystals of CdS with sizes between 2 and 16 nm. The analysis of VSCs revealed that P. fragi GC01 produced hydrogen sulfide (H2S), methanethiol (MeSH) and dimethyl sulfide (DMS) in the presence of sulfate, Met or Cys. Dimethyl disulfide (DMDS) was only detected in the presence of Met. Interestingly, MeSH was the main VSC produced in this condition. In addition, MeSH was the only VSC for which the concentration decreased in the presence of cadmium (Cd) of all the sulfur sources tested, suggesting that this gas interacts with Cd to form nanoparticles. The role of MeSH and DMS on Cds QDs biosynthesis was evaluated in two mutants of the Antarctic strain Pseudomonas deceptionensis M1T: megL- (unable to produce MeSH from Met) and mddA- (unable to generate DMS from MeSH). No biosynthesis of QDs was observed in the megL- strain, confirming the importance of MeSH in QD biosynthesis. In addition, the production of QDs in the mddA- strain was not affected, indicating that DMS is not a substrate for the biosynthesis of nanoparticles. Here, we confirm a link between MeSH production and CdS QDs biosynthesis when Met is used as sole sulfur source. This work represents the first report that directly associates the production of MeSH with the bacterial synthesis of QDs, thus revealing the importance of different VSCs in the biological generation of metal sulfide nanostructures

Estandarización Chilena de la Escala Wechsler de Inteligencia para Niños - Quinta Edición

  The Wechsler Intelligence Scale for Children — Fifth Edition is the most recent update to this scale, launched originally in 2014 in the United Stated. WISC-V includes several improvements from previous versions, such as an updated factorial structure that includes more indexes, new process scores and new procedures for norming. These improvements are particularly relevant in the Chilean context, since the previous version available in the country was the WISC-IIIv.ch, whose factorial structure dates from 1991, although it was standardized for Chilean population in 2007. This article presents the standardization process for the WISC-V, which includes the translation, adaptation and norming procedures for the Chilean population. It includes evidence for reliability and validity, and also results for various special groups samples, such as intellectual disability (24), attentional deficit disorder with hyperactivity (27), autism spectrum disorder (26), specific language disorder (56) and rural population (47). The Chilean data shows excellent reliability results and an excellent adjustment to the factorial model used in the North American version. This research provides evidence for convergent validity between WISC-V and other versions of these scales, such as the WAIS-IV and the WISC-IIIv.ch. Finally, we perform a comparison between private, voucher and public schools using this scale and a comparison between male and female performance in this scale. The main finding of this research is that the Chilean standardization of the WISC-V has excellent psychometric properties that allow recommending the use of this instrument in the country. <!-- [if gte mso 9]> <w:LsdException Locked="false" Priority="52" Name="Grid Table 7 ColorfulLa Escala Wechsler de Inteligencia para Niños — Quinta Edición es la más reciente actualización de estas escalas. Esta nueva edición fue lanzada el año 2014 en Estados Unidos y presenta mejoras relevantes respecto de versiones anteriores, como una estructura factorial actualizada que incluye un mayor número de indicadores, nuevos puntajes de proceso y nuevos procedimientos para la construcción de las normas. Estas mejoras son relevantes en el contexto nacional, puesto que la versión que estaba previamente disponible en Chile era WISC-IIIv.ch, cuya estructura factorial data del año 1991, aunque fue estandarizada el año 2007 para la población chilena. En este artículo se presenta el procedimiento de estandarización de WISC-V para la población chilena. Este procedimiento incluye la traducción, adaptación y construcción de normas. Se presenta evidencia de validez y confiabilidad, así como también los resultados de la aplicación del instrumento a muestras de grupos especiales, como discapacidad intelectual (24), trastorno de déficit atencional con hiperactividad (27), trastorno del espectro autista (26), trastorno específico del lenguaje (56) y población rural (47). Los resultados dan cuenta de excelentes resultados de confiabilidad, así como de un excelente ajuste al modelo factorial utilizado para la versión norteamericana. Por último, se presenta evidencia de validez convergente entre WISC-V y otras versiones de estas escalas de inteligencia, como WAIS-IV y WISC-IIIv.ch. También se presentan comparaciones de rendimiento entre los tres tipos de dependencia educativa existentes en Chile, así como también de comparaciones entre género. Los resultados de esta investigación dan cuenta que la estandarización chilena de WISC-V cuenta con excelentes características psicométricas que hacen recomendable su uso en el país

She\u27s So Bubbly

We introduce the Automatic Learning for the Rapid Classification of Events (ALeRCE) broker, an astronomical alert broker designed to provide a rapid and self-consistent classification of large etendue telescope alert streams, such as that provided by the Zwicky Transient Facility (ZTF) and, in the future, the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). ALeRCE is a Chilean-led broker run by an interdisciplinary team of astronomers and engineers working to become intermediaries between survey and follow-up facilities. ALeRCE uses a pipeline that includes the real-time ingestion, aggregation, cross-matching, machine-learning (ML) classification, and visualization of the ZTF alert stream. We use two classifiers: a stamp-based classifier, designed for rapid classification, and a light curve–based classifier, which uses the multiband flux evolution to achieve a more refined classification. We describe in detail our pipeline, data products, tools, and services, which are made public for the community (see https://alerce.science). Since we began operating our real-time ML classification of the ZTF alert stream in early 2019, we have grown a large community of active users around the globe. We describe our results to date, including the real-time processing of 1.5 × 10⁸ alerts, the stamp classification of 3.4 × 10⁷ objects, the light-curve classification of 1.1 × 10⁶ objects, the report of 6162 supernova candidates, and different experiments using LSST-like alert streams. Finally, we discuss the challenges ahead in going from a single stream of alerts such as ZTF to a multistream ecosystem dominated by LSST

Elective surgery system strengthening: development, measurement, and validation of the surgical preparedness index across 1632 hospitals in 119 countries

Background: The 2015 Lancet Commission on global surgery identified surgery and anaesthesia as indispensable parts of holistic health-care systems. However, COVID-19 exposed the fragility of planned surgical services around the world, which have also been neglected in pandemic recovery planning. This study aimed to develop and validate a novel index to support local elective surgical system strengthening and address growing backlogs. Methods: First, we performed an international consultation through a four-stage consensus process to develop a multidomain index for hospital-level assessment (surgical preparedness index; SPI). Second, we measured surgical preparedness across a global network of hospitals in high-income countries (HICs), middle-income countries (MICs), and low-income countries (LICs) to explore the distribution of the SPI at national, subnational, and hospital levels. Finally, using COVID-19 as an example of an external system shock, we compared hospitals' SPI to their planned surgical volume ratio (SVR; ie, operations for which the decision for surgery was made before hospital admission), calculated as the ratio of the observed surgical volume over a 1-month assessment period between June 6 and Aug 5, 2021, against the expected surgical volume based on hospital administrative data from the same period in 2019 (ie, a pre-pandemic baseline). A linear mixed-effects regression model was used to determine the effect of increasing SPI score. Findings: In the first phase, from a longlist of 103 candidate indicators, 23 were prioritised as core indicators of elective surgical system preparedness by 69 clinicians (23 [33%] women; 46 [67%] men; 41 from HICs, 22 from MICs, and six from LICs) from 32 countries. The multidomain SPI included 11 indicators on facilities and consumables, two on staffing, two on prioritisation, and eight on systems. Hospitals were scored from 23 (least prepared) to 115 points (most prepared). In the second phase, surgical preparedness was measured in 1632 hospitals by 4714 clinicians from 119 countries. 745 (45·6%) of 1632 hospitals were in MICs or LICs. The mean SPI score was 84·5 (95% CI 84·1–84·9), which varied between HIC (88·5 [89·0–88·0]), MIC (81·8 [82·5–81·1]), and LIC (66·8 [64·9–68·7]) settings. In the third phase, 1217 (74·6%) hospitals did not maintain their expected SVR during the COVID-19 pandemic, of which 625 (51·4%) were from HIC, 538 (44·2%) from MIC, and 54 (4·4%) from LIC settings. In the mixed-effects model, a 10-point increase in SPI corresponded to a 3·6% (95% CI 3·0–4·1; p<0·0001) increase in SVR. This was consistent in HIC (4·8% [4·1–5·5]; p<0·0001), MIC (2·8 [2·0–3·7]; p<0·0001), and LIC (3·8 [1·3–6·7%]; p<0·0001) settings. InterpBackground The 2015 Lancet Commission on global surgery identified surgery and anaesthesia as indispensable parts of holistic health-care systems. However, COVID-19 exposed the fragility of planned surgical services around the world, which have also been neglected in pandemic recovery planning. This study aimed to develop and validate a novel index to support local elective surgical system strengthening and address growing backlogs. Methods: First, we performed an international consultation through a four-stage consensus process to develop a multidomain index for hospital-level assessment (surgical preparedness index; SPI). Second, we measured surgical preparedness across a global network of hospitals in high-income countries (HICs), middle-income countries (MICs), and low-income countries (LICs) to explore the distribution of the SPI at national, subnational, and hospital levels. Finally, using COVID-19 as an example of an external system shock, we compared hospitals' SPI to their planned surgical volume ratio (SVR; ie, operations for which the decision for surgery was made before hospital admission), calculated as the ratio of the observed surgical volume over a 1-month assessment period between June 6 and Aug 5, 2021, against the expected surgical volume based on hospital administrative data from the same period in 2019 (ie, a pre-pandemic baseline). A linear mixed-effects regression model was used to determine the effect of increasing SPI score. Findings: In the first phase, from a longlist of 103 candidate indicators, 23 were prioritised as core indicators of elective surgical system preparedness by 69 clinicians (23 [33%] women; 46 [67%] men; 41 from HICs, 22 from MICs, and six from LICs) from 32 countries. The multidomain SPI included 11 indicators on facilities and consumables, two on staffing, two on prioritisation, and eight on systems. Hospitals were scored from 23 (least prepared) to 115 points (most prepared). In the second phase, surgical preparedness was measured in 1632 hospitals by 4714 clinicians from 119 countries. 745 (45·6%) of 1632 hospitals were in MICs or LICs. The mean SPI score was 84·5 (95% CI 84·1–84·9), which varied between HIC (88·5 [89·0–88·0]), MIC (81·8 [82·5–81·1]), and LIC (66·8 [64·9–68·7]) settings. In the third phase, 1217 (74·6%) hospitals did not maintain their expected SVR during the COVID-19 pandemic, of which 625 (51·4%) were from HIC, 538 (44·2%) from MIC, and 54 (4·4%) from LIC settings. In the mixed-effects model, a 10-point increase in SPI corresponded to a 3·6% (95% CI 3·0–4·1; p<0·0001) increase in SVR. This was consistent in HIC (4·8% [4·1–5·5]; p<0·0001), MIC (2·8 [2·0–3·7]; p<0·0001), and LIC (3·8 [1·3–6·7%]; p<0·0001) settings. Interpretation: The SPI contains 23 indicators that are globally applicable, relevant across different system stressors, vary at a subnational level, and are collectable by front-line teams. In the case study of COVID-19, a higher SPI was associated with an increased planned surgical volume ratio independent of country income status, COVID-19 burden, and hospital type. Hospitals should perform annual self-assessment of their surgical preparedness to identify areas that can be improved, create resilience in local surgical systems, and upscale capacity to address elective surgery backlogs.retation The SPI contains 23 indicators that are globally applicable, relevant across different system stressors, vary at a subnational level, and are collectable by front-line teams. In the case study of COVID-19, a higher SPI was associated with an increased planned surgical volume ratio independent of country income status, COVID-19 burden, and hospital type. Hospitals should perform annual self-assessment of their surgical preparedness to identify areas that can be improved, create resilience in local surgical systems, and upscale capacity to address elective surgery backlogs

Meaning Processes mediated through a Protagonists’ Collaborative Learning Platform

The use of Information and Communication Technologies (ICT) in the classroom requires the creation of contextualized proposals which foster in students collaboration and the use of resources to hand. This paper shows the results obtained in the analysis of the signification process which teachers and students have built through their participation in a project implementing collaborative didactic designs using ICT, in particular social networking. Focus groups were formed with 102 students and interviews with 21 teachers took place in two stages (pre and post), and they participated in 21 learning experiences developed at 12 schools in southern Chile. Main results reveal a positive assessment of the experience related to the motivational effects of the use of ICT and social networking among students; a considerable change in the didactic interaction inside the classroom; an interest in the possibility of collaborating with students from different contexts and from different regions; a lack of knowledge of the Web 2.0 resources available on the part of teachers, and some negative considerations on the inappropriate use of the Internet. In conclusion, the meaningcreation process of the protagonists enabled this study to gain relevant qualitative information related to didactic, technological and logistic factors in the development of learning experiences through a virtual learning platform

Relación entre nivel de resiliencia y éxito académico en alumnos de 7o y 8o año básico de la comuna de Talca

Tesis para optar al título de Profesor en Educación General BásicaEl presente estudio da cuenta de la investigación realizada en un grupo de adolescentes pertenecientes a escuelas municipales de la VII región, en torno a la mayor o menor capacidad para superar situaciones adversas que ellos posee y a como esta capacidad se relaciona con su éxito académico en las cuatro áreas fundamentales de la enseñanza (Educación Matemática, Lenguaje y comunicación, Comprensión del medio natural y Comprensión del medio social.). Se exponen algunos antecedentes de investigaciones realizadas en los últimos años con la finalidad de conocer los ámbitos estudiados y las variables que históricamente se han relacionado con este fenómeno. Luego se describen las características de los adolescentes, que fueron obtenidas a través del Test CD-RISC, agrupándolas en categorías de 1 a 5, siendo más resilientes quienes se acercan al puntaje máximo correspondiente a 125 puntos. La mirada que cruza este estudio es esencialmente cuantitativa tanto en su estructura metodológica como en su análisis. Finaliza el trabajo con la descripción de los resultados a través de gráficos

Vasculitis leucocitoclástica y síndrome antifosfolípido: reporte de un caso

Se presenta el caso de un paciente de sexo masculino de 47 años de edad, con antecedentes de hipertensión arterial, accidente cerebrovascular y TEP, que inicia cuadro caracterizado por lesiones ulceradas en piel pruriginosas y dolorosas en ambas extremidades inferiores, asociadas a daño renal progresivo. Se inició estudio con biopsia de piel y cultivos, sin aclarar el diagnostico de forma significativa. Posteriormente se realizan exámenes inmunológicos, comprobándose ANA positivo y Anti DNA positivo además de anticuerpos anticardiolipinas y anticoagulante lúpico positivos, diagnosticándose de este modo vasculitis leucocitoclástica en el contexto de un síndrome antifosfolípido. Actualmente el paciente ha tenido una buena respuesta a corticoides sistémicos y permanece con tratamiento anticoagulante oral para prevención de fenómenos tromboembolicos

Income redistribution in Latin America: A microsimulation approach

We analyse the effect of taxes and benefits on income distribution of six Latin American countries: Argentina, Bolivia, Colombia, Ecuador, Uruguay, and Venezuela. Our analysis makes use of tax-benefit microsimulation models based on harmonized household representative survey data and developed within the structure of EUROMOD. The analysis focuses on the relative importance of tax-benefit instruments across countries and on the effect of taxes and benefits on poverty and inequality. The selected countries represent a wide range of cases in terms of the redistributive role of the tax-benefit system with Uruguay providing a large degree of redistribution, whereas the Bolivian system has a very modest role. We further exploit the advantages of our models and perform a simulation exercise whereby the most progressive income tax system of our set of countries is applied to the rest and assess its effect on inequality and revenue. Our paper represents the first study making use of microsimulation techniques to assess the redistributive role of tax-benefit systems in the region in a comparable manner, and highlights the advantages offered by microsimulation models to evaluate the effect of policy reforms aiming to improve social protection in the region