Estudio de un fenómeno didáctico asociado a la representación gráfica de la función probabilidad

La presente investigación tiene por objetivo, indagar si el hecho didáctico que el docente no logra diferenciar entre la representación gráfico estadístico y gráfico cartesiano de la función probabilidad, es un buen candidato a fenómeno didáctico desde la perspectiva de docentes de matemática de enseñanza secundaria de Chile. Bajo el paradigma cualitativo, se lleva a cabo un estudio exploratorio. Por otra parte, para la recolección de datos se diseña un cuestionario basado en un ejercicio, extraído del texto de matemática del estudiante (16 y 17 años), distribuido por el ministerio de educación de Chile. Para el análisis de datos, se consideró categorías a priori emergentes de elementos teóricos. Los resultados evidencian, la necesidad de reforzar la representación y diferenciación entre gráfico estadístico y cartesiano de la función probabilidad en los docentes de matemática

Diretores de escolas públicas chilenas selecionados por “Alta Dirección” que forma demitidos antes de finalizar seu período de gestão: Aprendizados para a América Latina

This study exposes the opinions of a group of former directors of public schools in Chile who were selected by the system of high public management, and who had to leave their posts before the end of their appointment period. The responses evidence the fragility of the local organization of public education, in terms of the interference of the local political authority in the early dismissal of school leaders and identify the various pressures the leaders received from the higher authorities in the exercise of their position. The main problems they faced were the lack of support during the installation phases as well as a lack of monitoring and evaluation of their performance, which are widespread among Latin American countries, given the trends. This paper examines the selection process for High Public Management, the background on the subject, the answers of the interviewees, and an analysis of the interviews. It concludes with some proposals to improve the selection system. El texto expone las opiniones de un grupo de ex directores de establecimientos escolares públicos de Chile que fueron seleccionados por el sistema de Alta Dirección Pública, que debieron abandonar su cargo antes de finalizar su período de nombramiento, evidenciando la fragilidad de la organización local de la educación pública, en términos de la injerencia de la autoridad política local en la salida anticipada de los directivos escolares. Se identifican las diversas presiones recibidas desde las autoridades superiores en el ejercicio de su cargo, los principales problemas que enfrentaron, la ausencia de apoyo en las fases de instalación, seguimiento y evaluación de su desempeño, y las sugerencias que formulan para su mejoramiento, que son extensivas los países de la región latinoamericana, dada las tendencias que se presentan en esta perspectiva. Para la mejor comprensión del tema se expone el proceso de selección por Alta Dirección Pública, los antecedentes sobre el tema. Las respuestas de los entrevistados y su análisis final. Se concluye con algunas propuestas de mejoramiento del sistema de selección.O texto apresenta as opiniões de um grupo de ex-diretores de estabelecimentos escolares público do Chile que foram selecionados por o sistema de “Alta Dirección Pública” que deveram se afastar de seu cargo antes de finalizar seu período regular, mostrando a fragilidade da organização local da educação pública por deixar-se influenciar por autoridades políticas para influir em esse afastamento cedo. No texto, mais pontualmente, se desse identificam as diversas pressões exercidas pelas autoridades superiores de esses ex-diretores quando ainda exerciam seu cargo, os principais problemas que enfrentaram -a ausência de apoio nas fases de implantação, seguimento e avaliação de seu desempenho- e suas sugestões para o aprimoramento da função. Sugestões extensivas, devido às tendências que se apresentam em esta perspectiva, aos demais países da região latino-americana. Para ajudar a uma adequada compreensão do assunto se expõe o processo seletivo via “Alta Dirección Pública”, as respostas dos entrevistados e uma analise final. Conclui-se com algumas propostas de melhoramento do processo seletivo

The relationship between multidimensional poverty, income poverty and youth depressive symptoms: cross-sectional evidence from Mexico, South Africa and Colombia

Whereas monetary poverty is associated with increased risk of depressive symptoms in young people, poverty is increasingly understood as a multidimensional problem. However, it is yet to be understood how the associations between different dimensions of poverty and youth mental health differ across countries. We examine the relationship between multidimensional, as well as income poverty, and depressive symptoms in young people (age 11–25 years) across three middle-income countries. Based on harmonised data from surveys in Colombia, Mexico and South Africa (N=16 173) we constructed a multidimensional poverty index that comprised five deprivations. We used Poisson regression to examine relationships between different forms of poverty with depressive symptoms across the countries. Multidimensional poverty was associated with higher rates of depressive symptoms in the harmonised dataset (IRR (incidence rate ratio)=1.25, 95% CI 1.10 to 1.42), in Mexico (IRR=1.34, 95% CI 1.11 to 1.64) and Colombia (IRR=2.01, 95% CI 1.30 to 3.10) but not in South Africa, a finding driven by a lack of associations between child labour and health insurance coverage with depressive symptoms. There was only an association with income poverty and depressive symptoms in South Africa, not in Colombia or Mexico. Depressive symptoms were associated with individual deprivations such as school lag, child labour and lack of access to health services in the harmonised dataset, but not with household deprivations, such as parental unemployment and housing conditions, though the opposite pattern was observed in South Africa. Our findings suggest that the importance of specific dimensions of poverty for mental health varies across countries, and a multidimensional approach is needed to gain insights into the relationship between youth depression and poverty

Predictive ability of both the healthy aging index and the frailty index for all-cause mortality

Aim: We aimed to develop and assess a modified healthy aging index (HAI) among Chileans aged 60 years and older and compare its predictive ability for all-cause mortality risk with the frailty index (FI). Methods: This prospective study analyzed data from the Chilean National Health Survey (CNHS) conducted in 2009–2010. We included 847 adults with complete data to construct the HAI and FI. The HAI comprised five indicators (lung function, systolic blood pressure, fasting glucose, cognitive status, and glomerular filtration rate), while the FI assessed frailty using a 36-item scale. HAI scores were calculated by summing the indicator scores, ranging from 0 to 10, with higher scores indicating poorer health. Receiver operating curves (ROC) and area under the curve (AUC) were used to assess predictive validity. Associations with all-cause mortality were assessed using Cox proportional hazard models adjusted by confounders. Results: The mean HAI score was 4.06, while the FI score was 0.24. The AUC for mortality was higher for the HAI than the FI (0.640, 95% confidence interval (CI) 0.601 to 0.679 vs. 0.586, 95% CI 0.545 to 0.627). After adjusting for confounders, the FI showed a higher mortality risk compared to the HAI (2.63, 95% CI 1.76 to 3.51 vs. 1.16, 95% CI 1.08 to 1.26). Conclusion: The FI and HAI were valid predictors for all-cause mortality in the Chilean population. Integrating these indices into research and clinical practice can significantly enhance our capacity to identify at-risk individuals

A cyclic bipolar wind in the interacting binary V393 Scorpii

V393 Scorpii is a Double Periodic Variable characterized by a relatively stable non-orbital photometric cycle of 253 days. Mennickent et al. argue for the presence of a massive optically thick disc around the more massive B-type component and describe the evolutionary stage of the system. In this paper we analyze the behavior of the main spectroscopic optical lines during the long non-orbital photometric cycle. We study the radial velocity of the donor determining their orbital elements and find a small but significant orbital eccentricity (e = 0.04). The donor spectral features are modeled and removed from the spectrum at every observing epoch using the light-curve model given by Mennickent et al. We find that the line emission is larger during eclipses and mostly comes from a bipolar wind. We find that the long cycle is explained in terms of a modulation of the wind strength; the wind has a larger line and continuum emissivity on the high state. We report the discovery of highly variable chromospheric emission in the donor, as revealed by Doppler maps of the emission lines MgII 4481 and CI 6588. We discuss notable and some novel spectroscopic features like discrete absorption components, especially visible at blue-depressed OI 7773 absorption wings during the second half-cycle, Balmer double emission with V/R-curves showing "Z-type" and "S-type" excursions around secondary and main eclipse, respectively, and H_beta emission wings extending up to +- 2000 km/s. We discuss possible causes for these phenomena and for their modulations with the long cycle.Comment: 19 pages, 22 figures, accepted for publication in MNRA

The impact of cash transfers on mental health in children and young people in low-income and middle-income countries: a systematic review and meta-analysis

Introduction Although cash transfer programmes are not explicitly designed to improve mental health, by reducing poverty and improving the life chances of children and young people, they may also improve their mental health. This systematic review and meta-analysis assessed the evidence on the effectiveness of cash transfers to improve the mental health of children and young people in low-income and middle-income countries. Methods We searched Pubmed, EBSCOhost, Scientific Electronic Library Online, ISI Web of Science and Social Sciences Citation Index and grey literature (from January 2000 to July 2020) for studies which quantitatively assessed the impact of cash transfers on mental health in young people (aged 0–24 years), using a design that incorporated a control group. We extracted Cohen’s d effects size and used a random-effects model for the meta-analysis on studies that measured depressive symptoms, I2 statistic and assessment of study quality. Results We identified 12 116 articles for screening, of which 12 were included in the systematic review (covering 13 interventions) and seven in the meta-analysis assessing impact on depressive symptoms specifically. There was high heterogeneity (I2 =95.2) and a high risk of bias (0.38, 95% CIs: −5.08 to 5.85; p=0.86) across studies. Eleven interventions (85%) showed a significant positive impact of cash transfers on at least one mental health outcome in children and young people. However, no study found a positive effect on all mental health outcomes examined, and the meta-analysis showed no impact of cash transfers on depressive symptoms (0.02, 95% CIs: −0.19 to 0.23; p=0.85). Conclusion Cash transfers may have positive effects on some mental health outcomes for young people, with no negative effects identified. However, there is high heterogeneity across studies, with some interventions showing no effects. Our review highlights how the effect of cash transfers may vary by social and economic context, culture, design, conditionality and mental health outcome

Dangler for Accelerated Dehydration: A Novel System for Assessing the Impacts of Relative Humidity on Fruit Water Loss During Cold Storage of Blueberries

Blueberries are prone to dehydration during storage. Firmness is one of the most critical quality attributes associated with this period, with the loss of water from the fruit representing the most significant limitation for the fresh market. Therefore, one of the great challenges is maintaining the quality characteristics of the fruit in shipments by sea, which can take up to 60 days when sent from the southern hemisphere to the northern hemisphere. The random arrangement of each fruit within a packaging unit (different proportions of the stem scar and cuticular surface exposed to the environment) represents an essential source of variation in the prediction of softening during the storage period. A special device, referred to as a dangler for accelerated dehydration (DAD), was designed to expose nearly the entire fruit surface to the environment and determine the impact of factors such as relative humidity and the role of the stem scar and cuticle on fruit water loss. Consequently, to evaluate the ability of DADs to find differences in fruit dehydration, blueberries sampled at early, peak, and late harvest dates were placed in DADs and exposed to three controlled levels of relative humidity (30%, 65%, and 96% relative humidity; 1.2 ± 0.7 °C) for 10 days. Berries within the DADs were untreated, immersed in hexane for 5 seconds to remove bloom, painted with quick-drying nail polish on the pedicel end to seal the stem scar or immersed in hexane for 5 seconds, and painted with quick-drying nail polish on the pedicel end. At each harvest, fruit weight loss was significantly affected by the fruit and RH treatments, as well as the interaction between them. A regression analysis of the control treatment indicated that water loss at lower relative humidities occurred faster in fruit from the first harvest. The results reveal that DADs can be used to characterize preharvest and postharvest stimuli at an individual level and within a short time (10 days)

Fibroblast Primary Cilia are Required for Cardiac Fibrosis

Background: The primary cilium is a singular cellular structure that extends from the surface of many cell types and plays crucial roles in vertebrate development, including that of the heart. Whereas ciliated cells have been described in developing heart, a role for primary cilia in adult heart has not been reported. This, coupled with the fact that mutations in genes coding for multiple ciliary proteins underlie polycystic kidney disease, a disorder with numerous cardiovascular manifestations, prompted us to identify cells in adult heart harboring a primary cilium and to determine whether primary cilia play a role in disease-related remodeling. Methods: Histological analysis of cardiac tissues from C57BL/6 mouse embryos, neonatal mice, and adult mice was performed to evaluate for primary cilia. Three injury models (apical resection, ischemia/reperfusion, and myocardial infarction) were used to identify the location and cell type of ciliated cells with the use of antibodies specific for cilia (acetylated tubulin, γ-tubulin, polycystin [PC] 1, PC2, and KIF3A), fibroblasts (vimentin, α-smooth muscle actin, and fibroblast-specific protein-1), and cardiomyocytes (α-actinin and troponin I). A similar approach was used to assess for primary cilia in infarcted human myocardial tissue. We studied mice silenced exclusively in myofibroblasts for PC1 and evaluated the role of PC1 in fibrogenesis in adult rat fibroblasts and myofibroblasts. Results: We identified primary cilia in mouse, rat, and human heart, specifically and exclusively in cardiac fibroblasts. Ciliated fibroblasts are enriched in areas of myocardial injury. Transforming growth factor β-1 signaling and SMAD3 activation were impaired in fibroblasts depleted of the primary cilium. Extracellular matrix protein levels and contractile function were also impaired. In vivo, depletion of PC1 in activated fibroblasts after myocardial infarction impaired the remodeling response. Conclusions: Fibroblasts in the neonatal and adult heart harbor a primary cilium. This organelle and its requisite signaling protein, PC1, are required for critical elements of fibrogenesis, including transforming growth factor β-1-SMAD3 activation, production of extracellular matrix proteins, and cell contractility. Together, these findings point to a pivotal role of this organelle, and PC1, in disease-related pathological cardiac remodeling and suggest that some of the cardiovascular manifestations of autosomal dominant polycystic kidney disease derive directly from myocardium-autonomous abnormalities

The VASIMR[registered trademark] VF-200-1 ISS Experiment as a Laboratory for Astrophysics

The VASIMR[R] Flight Experiment (VF-200-1) will be tested in space aboard the International Space Station (ISS) in about four years. It will consist of two 100 kW parallel plasma engines with opposite magnetic dipoles, resulting in a near zero-torque magnetic system. Electrical energy will come from ISS at low power level, be stored in batteries and used to fire the engine at 200 kW. The VF-200-1 project will provide a unique opportunity on the ISS National Laboratory for astrophysicists and space physicists to study the dynamic evolution of an expanding and reconnecting plasma loop. Here, we review the status of the project and discuss our current plans for computational modeling and in situ observation of a dynamic plasma loop on an experimental platform in low-Earth orbit. The VF-200-1 project is still in the early stages of development and we welcome new collaborators

Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times $10^{-22}$.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200