Fluid motion for reducing the bounce of partially filled containers

Certain spatial distributions of water inside partially filled containers can significantly reduce the bounce of the container. In experiments with containers filled to a volume fraction $\phi$, we show that rotation offers control and high efficiency in setting such distributions and, consequently, in altering bounce markedly. High-speed imaging evidences the physics of the phenomenon and reveals a rich sequence of fluid-dynamics processes, which we translate into a model that captures our overall experimental findings.Comment: Submitted to Physical Review Letter

Tiempo en pantalla, tiempo sedentario y nivel del clima escolar en tiempos de pandemia en alumnos entre 11 y 14 años de la región de Valparaíso

Tesis (Profesor de Educación Física para la Enseñanza General Básica, Licenciado en Educación)Objetivo: Relacionar el tiempo en pantalla, tiempo sedentario y el nivel de clima escolar en tiempos de pandemia en alumnos entre 11 y 14 años de la Región de Valparaíso. Materiales y método: Estudio cuantitativo, descriptivo-analítico y no probabilístico. La muestra fue de 179 alumnos (104 mujeres y 75 hombres) entre los 11 y 14 años del Colegio Patmos de Viña del Mar y el Colegio Esperanza de Quilpué. Todos los alumnos contaban con el consentimiento informado firmado por sus padres y/o apoderados. Para medir el nivel de clima escolar se utilizó la Escala de Clima Social del Aula para alumnos (CSA) de Pérez et al., (2009) (Anexo II) y para identificar el uso de tecnologías y tiempo sedentario fue utilizado el Cuestionario YAP-SL. Resultados: Existió una relación negativa entre el tiempo de uso de PC con el clima escolar (r=-,213/p=0,004). Por otra parte, los hábitos sedentarios se relacionaron de manera negativa con el clima escolar (r=-0,239/p=0,001). Además, el tiempo en videojuegos (r=0,033/p=0,666) y en teléfono móvil (r=-0,073/p=0,334) no existe ningún tipo de relación. Por último, mencionar que el tiempo en TV tiene una relación positiva con la dimensión de competitividad (r=0,160/p=0,032). Conclusión: Se concluye que el tiempo de uso de PC y los hábitos sedentarios generan efectos negativos en el clima social del aula en el grupo de escolares. A partir de esto se sugiere aumentar los niveles de actividad física y disminuir el tiempo de uso de PC durante la pandemia para favorecer un mejor clima social en los escolares.Objective: Relate the time on screen, sedentary time and the level of school climate in times of pandemic in students between 11 and 14 years of the Valparaíso Region. Materials and method: Quantitative, descriptive-analytical and non-probabilistic study. The sample consisted of 179 students (104 women and 75 men) between the ages of 11 and 14 from Colegio Patmos de Viña del Mar and Colegio Esperanza de Quilpué. All students had the informed consent signed by their parents and / or guardians. To measure the level of school climate, the Classroom Social Climate Scale for students (CSA) by Pérez et al., (2009) (Annex II) was used and the YAP-Questionnaire was used to identify the use of technologies and sedentary time. SL. Results: There was a negative relationship between the time of PC use and the school climate (r= -, 213 / p = 0.004). On the other hand, sedentary habits were negatively related to the school climate (r= -0.239 / p= 0.001). In addition, time spent playing video games (r= 0.033 / p= 0.666) and on mobile phones (r= -0.073 / p= 0.334) there is no relationship of any kind. Lastly, it is worth mentioning that time spent on TV has a positive relationship with the competitiveness dimension (r= 0.160 / p= 0.032). Conclusion: It is concluded that the social climate of the general classroom is negatively related to the time of PC use and sedentary habits. Based on this, it is suggested to increase the levels of physical activity and decrease the time of PC use during the pandemic to favor a better social climate in schoolchildren

SEN1990 is a predicted winged helix-turn-helix protein involved in the pathogenicity of Salmonella enterica serovar Enteritidis and the expression of the gene oafB in the SPI-17

Excisable genomic islands (EGIs) are horizontally acquired genetic elements that harbor an array of genes with diverse functions. ROD21 is an EGI found integrated in the chromosome of Salmonella enterica serovar Enteritidis (Salmonella ser. Enteritidis). While this island is known to be involved in the capacity of Salmonella ser. Enteritidis to cross the epithelial barrier and colonize sterile organs, the role of most ROD21 genes remains unknown, and thus, the identification of their function is fundamental to understanding the impact of this EGI on bacterium pathogenicity. Therefore, in this study, we used a bioinformatical approach to evaluate the function of ROD21-encoded genes and delve into the characterization of SEN1990, a gene encoding a putative DNA-binding protein. We characterized the predicted structure of SEN1990, finding that this protein contains a three-stranded winged helix-turn-helix (wHTH) DNA-binding domain. Additionally, we identified homologs of SEN1990 among other members of the EARL EGIs. Furthermore, we deleted SEN1990 in Salmonella ser. Enteritidis, finding no differences in the replication or maintenance of the excised ROD21, contrary to what the previous Refseq annotation of the protein suggests. High-throughput RNA sequencing was carried out to evaluate the effect of the absence of SEN1990 on the bacterium’s global transcription. We found a downregulated expression of oafB, an SPI-17-encoded acetyltransferase involved in O-antigen modification, which was restored when the deletion mutant was complemented ectopically. Additionally, we found that strains lacking SEN1990 had a reduced capacity to colonize sterile organs in mice. Our findings suggest that SEN1990 encodes a wHTH domain-containing protein that modulates the transcription of oafB from the SPI-17, implying a crosstalk between these pathogenicity islands and a possible new role of ROD21 in the pathogenesis of Salmonella ser. Enteritidis

Cinco dimensiones de la crisis en América Latina (1990-2021)

This article addresses the recent crises in Latin America from five dimensions: political, social, economic, environmental and health. Based on research from the Crisis Observatory of the Faculty of Humanities of the University of Santiago, it analyzes the theoretical debates on the conceptualization of crises, makes operational five dimensions of the crises in Latin America and examines each of these from a mixed methodology which includes a review of the literature, quantitative indicators, and a press review. Analyzing ten countries in the region from 1990 to date, this work proposes that Latin America has experienced cycles of multidimensional crisis, which are expressed in the five dimensions mentioned above, which are shown cross-sectionally in the cases examined.El presente artículo aborda las crisis recientes de América Latina desde cinco dimensiones: política, social, económica, medio ambiente y sanitaria. A partir de investigaciones del Observatorio de Crisis de la Facultad de Humanidades de la Universidad de Santiago, analiza debates teóricos sobre la conceptualización de crisis, operativiza cinco dimensiones de las crisis en América Latina y examina cada una de éstas a partir de una metodología mixta que incluye revisión de literatura, indicadores cuantitativos y revisión de prensa. Analizando diez países de la región desde 1990 a la fecha, este trabajo plantea que América Latina ha vivido ciclos de crisis de carácter multidimensional, que se expresan en las cinco dimensiones antes señaladas, que se muestran transversalmente en los casos examinados

"Cooperativas" : percepción del concepto y casos de marketing cooperativo en Chile

Seminario para optar al grado de Ingeniero Comercial, Mención AdministraciónEste estudio nace por la necesidad de conocer cómo se encuentra posicionado el concepto de “cooperativas” actualmente en Chile y cuáles son las acciones de marketing que toman estas empresas para mejorar su desarrollo. Es por esto que se identifica el siguiente problema de investigación: “¿Debe reposicionarse el concepto cooperativas o marca COOP en la sociedad chilena actualmente?”. Este problema se busca resolver mediante una investigación que se resume en la pregunta entregada a continuación: “¿Qué aspectos/atributos positivos y negativos perciben las personas de las cooperativas?” El método de recolección de datos para el estudio fue variado, partiendo en la fase exploratoria con la recopilación y análisis de datos secundarios, y la realización de focus groups y entrevistas en profundidad. Posteriormente, en la fase descriptiva se realiza un muestreo no probabilístico por conveniencia para las encuestas por internet, en donde se enfoca principalmente en los jóvenes de 18 a 28 años de la Región Metropolitana. Por otro lado, se realizó también un estudio de casos de 4 importantes cooperativas a nivel nacional, donde se estudió su historia y su estrategia de marketing, todo esto a partir de recopilación de datos secundarios y entrevistas en profundidad a personas estrechamente relacionadas con las cooperativas analizadas. Consecutivamente a esta investigación se lograron una serie de importantes conclusiones donde se destaca el bajo conocimiento de los jóvenes respecto al concepto “cooperativa”, lo que se asocia por el contexto histórico vivido en Chile, en donde el golpe militar corto el crecimiento de este modelo en el país e intervino las cátedras que se enseñaban en las principales universidades de Chile. Por otro lado, los jóvenes asocian mayoritariamente el concepto a algo positivo, derivado generalmente por la definición de “cooperación”, teniendo con esto una diferencia con las personas de mayor edad, los cuales asocian más que nada el concepto a algo negativo, dado que les toco vivir en la época de declive del modelo en Chile

Assessment of Postpartum Depression in a Group of Chilean Parents

Background and objective: Several studies have shown that not only mothers, but also fathers can suffer from peripartum depression. This phenomenon has not been researched in Chile; therefore, the aim of present study is to explore the presence of depressive symptoms in fathers and mothers during the postpartum period and describe their interaction. Material and Methods: users of the Western Metropolitan Health Service Unit were assessed two months after childbirth with a sociodemographic questionnaire, the Beck Depression Inventory (BDI-I), and the Edinburgh Postnatal Depression Scale (EPDS). Results: even though mothers score significantly higher in both scales, 18.5% of men surpass the cutoff score in the EPDS and 10.5% in the BDI-I. Conclusion: these results stress the need to continue researching this phenomenon and incorporate father assessment in perinatal checkups. Keywords: depression, peripartum, fathers, Edinburgh Postnatal Depression Scal

Novel and recurrent COL7A1 mutations in Chilean patients with dystrophic epidermolysis bullosa

Artículo de publicación IS

Image_6_Human metapneumovirus respiratory infection affects both innate and adaptive intestinal immunity.jpeg

IntroductionRespiratory infections are one of the leading causes of morbidity and mortality worldwide, mainly in children, immunocompromised people, and the elderly. Several respiratory viruses can induce intestinal inflammation and alterations in intestinal microbiota composition. Human metapneumovirus (HMPV) is one of the major respiratory viruses contributing to infant mortality in children under 5 years of age worldwide, and the effect of this infection at the gut level has not been studied.MethodsHere, we evaluated the distal effects of HMPV infection on intestinal microbiota and inflammation in a murine model, analyzing several post-infection times (days 1, 3, and 5). Six to eight-week-old C57BL/6 mice were infected intranasally with HMPV, and mice inoculated with a non-infectious supernatant (Mock) were used as a control group.ResultsWe did not detect HMPV viral load in the intestine, but we observed significant changes in the transcription of IFN-γ in the colon, analyzed by qPCR, at day 1 post-infection as compared to the control group. Furthermore, we analyzed the frequencies of different innate and adaptive immune cells in the colonic lamina propria, using flow cytometry. The frequency of monocyte populations was altered in the colon of HMPV -infected mice at days 1 and 3, with no significant difference from control mice at day 5 post-infection. Moreover, colonic CD8+ T cells and memory precursor effector CD8+ T cells were significantly increased in HMPV-infected mice at day 5, suggesting that HMPV may also alter intestinal adaptive immunity. Additionally, we did not find alterations in antimicrobial peptide expression, the frequency of colonic IgA+ plasma cells, and levels of fecal IgA. Some minor alterations in the fecal microbiota composition of HMPV -infected mice were detected using 16s rRNA sequencing. However, no significant differences were found in β-diversity and relative abundance at the genus level.DiscussionTo our knowledge, this is the first report describing the alterations in intestinal immunity following respiratory infection with HMPV infection. These effects do not seem to be mediated by direct viral infection in the intestinal tract. Our results indicate that HMPV can affect colonic innate and adaptive immunity but does not significantly alter the microbiota composition, and further research is required to understand the mechanisms inducing these distal effects in the intestine.</p

Image_3_Human metapneumovirus respiratory infection affects both innate and adaptive intestinal immunity.jpeg

IntroductionRespiratory infections are one of the leading causes of morbidity and mortality worldwide, mainly in children, immunocompromised people, and the elderly. Several respiratory viruses can induce intestinal inflammation and alterations in intestinal microbiota composition. Human metapneumovirus (HMPV) is one of the major respiratory viruses contributing to infant mortality in children under 5 years of age worldwide, and the effect of this infection at the gut level has not been studied.MethodsHere, we evaluated the distal effects of HMPV infection on intestinal microbiota and inflammation in a murine model, analyzing several post-infection times (days 1, 3, and 5). Six to eight-week-old C57BL/6 mice were infected intranasally with HMPV, and mice inoculated with a non-infectious supernatant (Mock) were used as a control group.ResultsWe did not detect HMPV viral load in the intestine, but we observed significant changes in the transcription of IFN-γ in the colon, analyzed by qPCR, at day 1 post-infection as compared to the control group. Furthermore, we analyzed the frequencies of different innate and adaptive immune cells in the colonic lamina propria, using flow cytometry. The frequency of monocyte populations was altered in the colon of HMPV -infected mice at days 1 and 3, with no significant difference from control mice at day 5 post-infection. Moreover, colonic CD8+ T cells and memory precursor effector CD8+ T cells were significantly increased in HMPV-infected mice at day 5, suggesting that HMPV may also alter intestinal adaptive immunity. Additionally, we did not find alterations in antimicrobial peptide expression, the frequency of colonic IgA+ plasma cells, and levels of fecal IgA. Some minor alterations in the fecal microbiota composition of HMPV -infected mice were detected using 16s rRNA sequencing. However, no significant differences were found in β-diversity and relative abundance at the genus level.DiscussionTo our knowledge, this is the first report describing the alterations in intestinal immunity following respiratory infection with HMPV infection. These effects do not seem to be mediated by direct viral infection in the intestinal tract. Our results indicate that HMPV can affect colonic innate and adaptive immunity but does not significantly alter the microbiota composition, and further research is required to understand the mechanisms inducing these distal effects in the intestine.</p