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A review on bioflocculation using microalgae for nutrient removal from wastewater
Get PDFIn recent decades, the eutrophication of surface water has become a major environmental concern. Increased concentration of nutrients such as nitrogen and phosphorous lead to eutrophication condition which highlights the demand for effective and economical methods of removing nitrogen and phosphorous from wastewater. Bio flocculationusing microalgae is an excellent candidate for satisfying the dual purposeof nutrient removal and wastewater treatment. It has so many advantagesover conventional methods such as toxic free, no chemical is needed, low cost etc. Inthis reviewthe bio flocculationof microalgae, its mechanisms, applicationsand harvesting methods are discussed.En las últimas décadas, la eutrofización de las aguas superficiales se ha convertido en una de las principales preocupaciones medioambientales. El aumento de la concentración de nutrientes como el nitrógeno y el fósforo conduce a una condición de eutrofización que resalta la demanda de métodos efectivos y económicos para eliminar el nitrógeno y el fósforo de las aguas residuales. La bio-floculación con microalgas es un excelente candidato para satisfacer el doble propósito de la eliminación de nutrientes y el tratamiento de aguas residuales. Tiene tantas ventajas sobre los métodos convencionales como libre de tóxicos, no se necesitan productosquímicos, bajo costo, etc. En esta revisión se discute la biofloculación de microalgas, sus mecanismos, aplicaciones y métodos de recolección
Learning-oriented motivation: Examining the impact of teaching practices with motivational potential
No full textThis study compares the predictive ability of nine different types of motivational practices on the motivational orientation toward learning. Given the nature of undergraduate studies, identifying the most predictive motivational variables on learning orientation allows us to focus our efforts on those motivational practices to guide students to deploy their cognitive resources by focusing on learning and not only on obtaining good grades. The study included Chilean university students from health (n = 398) and education (n = 365) programs. A Bayesian multiple regression was carried out in both groups. The results show strong evidence of a specific effect of motivational practices on motivational orientation towards learning. Although the impact on motivational orientation toward learning may vary slightly across different fields of study, the primary predictors consistently are practices that emphasize importance and foster autonomy. The effect of utility-focused motivational practices is observed only within the predictive model for the group of health students
Drought Resistant Resting Cysts of <i>Paraphysoderma sedebokerense</i> Preserves the Species Viability and Its Virulence
No full textThe blastocladialean fungus P. sedebokerense is a facultative parasite of economically important microalgae and for this reason it has gained a lot of interest. P. sedebokerense has a complex life cycle which includes vegetative and resting stages. The resting cysts were assumed to play an essential role in survival by resisting drought, but this ability was never tested and the factors that trigger their formation were not evaluated. This study was aimed to induce resting cyst formation and germination in P. sedebokerense. At first, we tested the survival of P. sedebokerense liquid cultures and found that infectivity is retained for less than two months when the cultures were stored on the bench at room temperature. We noticed that dry cultures retained the infectivity for a longer time. We, thus, developed a method, which is based on dehydration and rehydration of the biomass, to produce, maintain, and germinate resting cysts of P. sedebokerense in both saprophytic and parasitic modes of growth. When the dry cultures were rehydrated and incubated at 30 degree celsius, resting cysts asynchronously germinated after 5 h and the 'endosporangium' was protruding outside of the cyst. Our method can be used to preserve P. sedebokerense for research purposes with the advantage of no need for expensive equipment
Environmental Paucity and Anthropocentrism in Textbooks on the Occupation of Araucanía, and a Solution From the Fields of Environmental History and Environmental Education
Get PDFLa interculturalidad en los libros de texto asociados a la temática de la ocupación militar de La Araucanía no avanzará si solo presta atención a cuestiones sociales o políticas. El medio ambiente también debe ser integrado. El presente estudio realiza un análisis ambiental a los libros de texto de enseñanza media asociados a dicho contenido de la historia de Chile. Se ocupó una estrategia de investigación mixta y un diseño de investigación múltiple. La muestra estuvo compuesta por seis libros de texto de la asignatura de Historia y Geografía usados en educación secundaria desde el año 2008 al 2021. Los datos fueron sometidos a un análisis de contenido cuantitativo y a un análisis documental. Los resultados muestran que existe una limitada representación de la biodiversidad y de los ecosistemas, y que no existen actividades didácticas que fomenten en los estudiantes una actitud y comportamiento más sustentables con el medio. Más importante aún, el medio ambiente es tratado desde una óptica antropocéntrica, lo cual no considera la relación medioambiental biocéntrica que suele caracterizar a los pueblos aborígenes y, en este caso, a los mapuche. Por tanto, una vinculación más efectiva de los contenidos con los principios de la educación ambiental y de la historia ambiental podría corregir estos sesgos. Así, se fomentarían metodologías más tolerantes a la diversidad humana, se elevaría el rol del medio ambiente en la historia humana, y se alinearían los contenidos de libros de texto con la sustentabilidad que necesita el mundo de hoy.There will be no progress in the interculturality of textbooks associated with the topic of the military occupation of the Araucanía region if attention is only paid to political or social matters. The environment should also be included. This study provides an environmental analysis of secondary education textbooks that cover this content on the history of Chile. A mixed research strategy and a multiple research design were employed. The sample was composed of eight textbooks used in the secondary school subject of History and Geography from 2008 to 2021. The data were subjected to a quantitative content analysis and a documentary analysis. The results show that there is only limited representation of biodiversity and ecosystems, as well as a lack of didactic activities that foster environmentally friendly behavior and attitudes among students. More importantly, the environment is addressed from an anthropocentric perspective, which does not consider the biocentric environmental relationship that tends to characterize aboriginal peoples and, in this case, the Mapuche people. A more effective link with the tenets of environmental history and environmental education could correct these biases. This would foster methodologies that are more focused on human diversity, the role of the environment in human history would be highlighted, and the content of textbooks would be aligned with the sustainability that is required in the modern world
Intra- and Inter-Individual Associations of Family-to-Work Conflict, Psychological Distress, and Job Satisfaction: Gender Differences in Dual-Earner Parents during the COVID-19 Pandemic
No full textThe COVID-19 pandemic changed the work-family interface dynamics in some families. For couples who kept earning a double income during the pandemic, their family demands may entail a loss of psychological resources that affect the work domain. This study explored the intra-individual and inter-individual (crossover) direct and indirect effects of family-to-work conflict (FtoWC) on psychological distress and job satisfaction in a non-probabilistic sample of 860 different-sex dual-earner parents with adolescent children from Temuco and Rancagua, Chile. Mothers and fathers answered an online questionnaire measuring FtoWC, the Depression, Anxiety, and Stress Scale, and the Overall Job Satisfaction Scale. The data were analyzed using the actor-partner interdependence model with structural equation modeling. Results showed that a higher FtoWC is linked to greater psychological distress and lower job satisfaction in both parents. In contrast, psychological distress is directly linked to lower job satisfaction in fathers. In both fathers and mothers, they and their partners' FtoWC were indirectly linked to lower job satisfaction via the fathers' psychological distress. These findings indicate the need for gender-sensitive social and labor policies aimed at reducing the conflict between family and work to increase job satisfaction in both parents and reduce psychological distress, particularly in fathers
A Family of Truncated Positive Distributions
No full textIn this paper, a new family of continuous distributions with positive support is introduced. This family is generated by a truncation of the family of univariate symmetrical distributions. In this new family of distributions, general properties, such as moments, asymmetry and kurtosis coefficients, are derived. Particular cases of interest based on the normal, logistic, Laplace and Cauchy models are discussed in depth. The estimation of parameters is carried out by applying moments and maximum likelihood methods. Also, a simulation study was conducted to illustrate the good performance of estimators. An application to the Survival Times (in days) of Guinea Pigs dataset is included, where the special cases of distributions in this family are fitted. The option which provides the best fit is ultimately chosen. An R package, called 'tpn', has been implemented, which includes the relevant cases of interest in this family
Hospitalization is associated with handgrip strength decline in older adults: a longitudinal study
No full textBackground
Hospitalization episodes in older people are considered critical events because they act in a complex interaction among immobilization effects.
Aim
The purpose of this study was to evaluate the effects of hospitalization on older adults’ handgrip strength (HGS) and to identify factors related to its performance on the test.
Methods
A cohort study was conducted in a hospital in Natal, Brazil, and enrolled all patients aged 60 years and older between January 2014, and April 2015. Cognitive (Leganés Cognitive Test) and functional status (Katz Index, Lawton Scale and Functional limitation Nagi), physical performance (HGS and gait speed) and depressive symptom assessment (GDS-15) were evaluated at admission and discharge time, as well as information about health and functional status prior to hospitalization. Linear Mixed Models were used to create a predictive model for handgrip strength.
Results
A total of 1168 hospitalized older adults were evaluated. A significant decrease in HGS means was observed between admission and discharge time for men (28.12 ± 10.35 and 20.22 ± 14.08 Kgf, p < 0.01) and for women (19.18 ± 7.87 and 14.88 ± 9.79 Kgf, p < 0.01). Undergoing surgery and basal values of the Katz Index were associated with worse HGS performance at discharge.
Conclusion
A significant decline in handgrip strength during the hospitalization period was observed, which was more pronounced in men. Performing surgery during hospitalization was an important factor for HGS decline in men and women. This study reinforces the importance of early mobilization and muscle strength loss prevention protocols in hospitalized older patients
Effect of healthy and unhealthy habits on obesity: a multicentric study
No full textObjective: Our aim was to characterize and compare eating patterns of university students in Chile, by sex and body weight, body mass index, and nutritional status.
Methods: This was a cross-sectional study. University students (n = 1454) of Chile were evaluated. A self-assessment survey was used to evaluate healthy eating habits using a questionnaire with values between 1 (do not consume) and 5 (consume) for a total of 9 to 45 points (higher values represent better eating habits). Unhealthy habits were assessed with six questions, including consumption of sugary soft drinks, alcohol, fried foods, fast food, and snacks and adding salt to foods without tasting first.
Results: Obese students had a lower consumption of healthy foods (P = servings of vegetables (OR = 0.5; 95% CI 0.4-0.7). Risk factors included consumption (more than 1 cup a day) of sugary soft drinks (OR = 1.5; 95% CI 1.0-2.1) and male sex (OR = 1.8; 95% CI 1.3-2.4).
Conclusion: The consumption of vegetables and belonging to an undergraduate program in health sciences at a university contributed to protection against for obesity. On the other hand, male sex and consumption of sugary drinks were found to be risk factors for obesity. (C) 2018 Elsevier Inc. All rights reserved
Should we take care of each other? Enhancing COVID-19 protective behaviors, a study in Chile, Mexico, and Colombia
No full textThe literature has suggested that social norms and perceptions of risk and severity are critical variables in predicting protective health behaviors. Using an integrative conceptual framework, this study evaluates educational level, socioeconomic status, injunctive pro-care norms, perception of risk, and severity of COVID-19 as predictors of hygiene behaviors, mask use, and physical distancing. Participants included 2,075 adults from Chile, Mexico, and Colombia, three countries with the worst pandemic management. A structural equation model including the hypothesized structure of relations among the study variables fitted the data well and was invariant among Chilean, Mexican, and Colombian data. As proposed, injunctive pro-care norms against COVID-19 predicted protective health behaviors directly and indirectly through the perception of the risk and severity of COVID-19, and educational level predicted pro-care norms against COVID-19. These findings are essential in light of the development of prevention campaigns and the promotion of COVID-19 care strategies
Utopía, pragmatismo y vivienda social: De las “habitaciones obreras” a los “huertos obreros y familiares” en Santiago, 1900 – 1960
Get PDFLa consolidación de los programas de vivienda popular en Chile en la primera mitad del siglo XX debe entenderse bajo las dinámicas de la disputa política y la configuración del espacio urbano, las cuales responden a las alianzas entre los sectores trabajadores y el Estado. En este trabajo se analiza cómo esa trayectoria está mediada por perspectivas proyectuales utópicas por parte de ambos agentes, hasta llegar a los huertos obreros como materialización concreta de aquellas utopías abstractas. Se revisaron los documentos oficiales y publicaciones de los principales gestores de las experiencias de producción de un espacio urbano específico, Santiago en la primera mitad del siglo XX. Se puso el énfasis en lo que iba más allá de la acción meramente habitacional, sino que iban más allá, problematizando no sólo el derecho a la vivienda, sino que el cómo debía ser materializado ese derecho. La cuestión utópica, como horizonte de posibilidad, permite argumentar que los proyectos de vivienda popular lograron verse permeados por formas alternativas de habitar la ciudad.A consolidação de programas habitacionais populares no Chile na primeira metade do século XX deve ser entendida sob a dinâmica da disputa política e da configuração do espaço urbano, que respondem a alianças entre os setores de trabalhadores e o Estado. Neste artigo, analisamos como essa trajetória é mediada pelas perspectivas projetivas utópicas de ambos agentes, até chegarem às hortas dos trabalhadores como materialização concreta dessas utopias abstratas. Documentos oficiais e publicações dos principais gestores das experiências de produção de um espaço urbano específico, Santiago, na primeira metade do século XX, foram revisados. A ênfase foi colocada não apenas naquilo que foi além da mera ação habitacional, mas também, problematizando não apenas o direito à moradia, mas como esse direito deveria ser materializado. A questão utópica, como horizonte de possibilidade, permite argumentar que os projetos habitacionais populares conseguiram ser permeados por formas alternativas de habitar a cidade