Search results for: chilean abalone

Authors: Mario Pérez-Won, Anais Palma-Acevedo, Luis González-Cavieres, Roberto Lemus-Mondaca, Gipsy Tabilo-Munizaga

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The Chilean abalone (Concholepas Concholepas) is a gastropod mollusk; it has a high commercial value due to the qualities of its meat, especially hardness, as a critical acceptance parameter. However, its main problem is its short shelf-life which is usually extended using traditional technologies with high energy consumption. Therefore, applying different technologies for the pre-treatment and drying process is necessary. In this research, pulsed electric field (PEF) was used as a pre-treatment for vacuum microwave drying (VMD), freeze-drying (FD), and hot-air drying (HAD). Drying conditions and characteristics were set according to previous experiments. The Drying samples were analyzed in terms of physical quality (color, texture, microstructure, and rehydration capacity), protein quality (degree of hydrolysis and computer protein efficiency ratio), and energy parameters. Regarding quality, the treatment that obtained lower harness was PEF+FD (195 N ± 10), the lowest change of color was for treatment PEF+VMD (ΔE: 17 ± 1.5), and the best rehydration capacity was for treatment PEF+VMD (1.2 h for equilibrium). For protein quality, the highest Computer-Protein Efficiency Ratio was the sample 2.0 kV/ cm of PEF (index of 4.18 ± 0.26 at the end of the digestion). Moreover, about energetic consumption, results show that VMD decreases the drying process by 97% whether PEF was used or not. Consequently, it is possible to conclude that using PEF as a pre-treatment for VMD and FD treatments has advantages that must be used following the consumer’s needs or preferences.

Keywords: chilean abalone, freeze-drying, proteins, pulsed electric fields

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Authors: Luis González-Cavieres, Mario Perez-Won, Anais Palma-Acevedo, Gipsy Tabilo-Munizaga, Erick Jara-Quijada, Roberto Lemus-Mondaca

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In this study, pulsed electric field (PEF: 2.0 kV/cm) was used as pretreatment in drying methods, vacuum microwave (VMD); freeze-drying (FD); and hot air (HAD), in Chilean abalone mollusk. Drying parameters, quality, energy consumption, and Sustainability parameters were evaluated. PEF+VMD showed better values than the other drying systems, with drying times 67% and 83% lower than PEF+FD and FD. In the quality parameters, PEF+FD showed a significantly lower value for hardness (250 N), and a lower change of color value (ΔE = 12). In the case of HAD, the PEF application did not significantly influence its processing. In energy parameters, VMD and PEF+VMD reduced energy consumption and CO2 emissions.

Keywords: PEF technology, vacuum microwave drying, energy consumption, CO2 emissions

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Authors: Aldi Nel, Cliff L. W. Jones, Justin O. G. Kemp, Peter J. Britz

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Kelp Ecklonia maxima is included in formulated abalone feeds in South Africa, but its effect on abalone growth, feed utilisation efficiency and gut-bacterial communities has not previously been investigated. An eight-month on-farm growth trial with sub-adult Haliotis midae (~43 mm shell length) fed graded levels of kelp in formulated feeds was conducted. Kelp inclusion (0.44–3.54 % of pellet dry mass) promoted faster growth (65.7 – 74.5 % total mass gain), with better feed and protein conversions (FCR: 1.4 – 1.8; PER 2.3 – 2.7), compared to abalone fed the non-supplemented feed (52.3% total mass gain; FCR: 2.1; PER 1.9; p < 0.001). The gut-bacterial communities of abalone fed kelp-supplemented feed (0.88 % of pellet dry mass) were subsequently compared with that of abalone fed a non-supplemented control diet. Abalone gut-bacterial DNA was sequenced using 16S rRNA pyrosequencing and sequences were clustered into operational taxonomic units (OTUs) at a 97 % similarity level. A supplementary 16S rRNA denaturing gradient gel electrophoresis (DGGE) analysis was conducted. The dominant OTUs differed in terms of their relative abundances, with that of an autochthonous Mollicutes strain being significantly higher (p = 0.03) in the guts of abalone fed kelp-supplemented feed. The DGGE band patterns displayed a higher within-group variability of dominant bacterial strains for abalone fed the control diet, suggesting that dietary inclusion of kelp, which is rich in fermentable polysaccharides, promotes a balanced gut-bacterial community. This may contribute to the better feed utilisation and growth in abalone fed kelp-supplemented feeds.

Keywords: abfeed, digestion, macroalgae, mariculture

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Authors: Bangoura Issa, Ji-Young Kang, M. T. H. Chowdhury, Ji-Eun Lee, Yong-Ki Hong

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Investigation was carried out for the production of value-added abalone Haliotis discus hannai containing bioactive phlorotannin by feeding phlorotannin-rich seaweed Eisenia bicyclis 2 weeks prior to harvesting. Accumulation of phlorotannins was proceded by feeding with E. bicyclis after 4 days of starvation. HPLC purification afforded two major phlorotannins. Mass spectrometry and 1H-nuclear magnetic resonance analysis clarified their structures to be as 7-phloroeckol and eckol. Throughout the feeding period of 20 days, 7-phloroeckolol was accumulated in the muscle (foot muscle tissue) up to 0.18±0.12 mg g-1 dry weight of tissue after 12 days. Eckol reached 0.21±0.03 mg g-1 dry weight of tissue after 18 days. By feeding Laminaria japonica as reference, abalone showed no detection of phlorotannins in the muscle tissue. Seaweed consumption and growth rate of abalone revealed almost similar when feed with E. bicyclis or L. japonicain 20 days. Phlorotannins reduction to half-maximal accumulation values took 1.0 day and 2.7 days for 7-phloroeckol and eckol respectively, after replacing the feed to L. japonica.

Keywords: abalone, accumulation, eisenia bicyclis, phlorotannins

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Authors: Teresa Roco, Mario Perez Won, Roberto Lemus-Mondaca, Sebastian Pizarro

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This research presents the simultaneous application of high hydrostatic pressure application (HHP) and osmotic dehydration (DO) as a pretreatment to hot –air drying of abalone cubes. The drying time was reduced to 6 hours at 60ºC as compared to the abalone drying by only a 15% NaCl osmotic pretreatment and at an atmospheric pressure that took 10 hours to dry at the same temperature. This was due to the salt and HHP saturation since osmotic pressure increases as water loss increases, thus needing a more reduced time in a convective drying, so water effective diffusion in drying plays an important role in this research. Different working conditions as pressure (350-550 MPa), pressure time ( 5-10 min), salt concentration, NaCl 15% and drying temperature (40-60ºC) will be optimized according to kinetic parameters of each mathematical model (Table 1). The models used for drying experimental curves were those corresponding to Weibull, Logarithmic and Midilli-Kucuk, but the latest one was the best fitted to the experimental data (Figure 1). The values for water effective diffusivity varied from 4.54 – to 9.95x10-9 m2/s for the 8 curves (DO+HHP) whereas the control samples (neither DO nor HHP) varied among 4.35 and 5.60x10-9 m2/s, for 40 and 60°C, respectively and as to drying by osmotic pretreatment at 15% NaCl from 3.804 to 4.36x10-9 m2/s at the same temperatures. Finally as to energy and efficiency consumption values for drying process (control and pretreated samples) it was found that they would be within a range of 777-1815 KJ/Kg and 8.22–19.20% respectively. Therefore, a knowledge concerning the drying kinetic as well as the consumption energy, in addition to knowledge about the quality of abalones subjected to an osmotic pretreatment (DO) and a high hydrostatic pressure (HHP) are extremely important to an industrial level so that the drying process can be successful at different pretreatment conditions and/or variable processes.

Keywords: abalone, convective drying, high pressure hydrostatic, pretreatments, diffusion coefficient

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Authors: Ghaneshree Moonsamy, Nodumo N. Zulu, Rajesh Lalloo, Suren Singh, Santosh O. Ramchuran

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The abalone industry of South Africa is under severe pressure due to illegal harvesting and poaching of this seafood delicacy. These abalones are harvested excessively; as a result, these animals do not have a chance to replace themselves in their habitats, ensuing in a drastic decrease in natural stocks of abalone. Abalone has an extremely slow growth rate and takes approximately four years to reach a size that is market acceptable; therefore, it was imperative to investigate methods to boost the overall growth rate and immunity of the animal. The University of Cape Town (UCT) began to research, which resulted in the isolation of two microorganisms, a yeast isolate Debaryomyces hansenii and a bacterial isolate Vibrio midae, from the gut of the abalone and characterised them for their probiotic abilities. This work resulted in an internationally competitive concept technology that was patented. The next stage of research was to develop a suitable bioprocess to enable commercial production. Numerous steps were taken to develop an efficient production process for V. midae, one of the isolates found by UCT. The initial stages of research involved the development of a stable and robust inoculum and the optimization of physiological growth parameters such as temperature and pH. A range of temperature and pH conditions were evaluated, and data obtained revealed an optimum growth temperature of 30ᵒC and a pH of 6.5. Once these critical growth parameters were established further media optimization studies were performed. Corn steep liquor (CSL) and high test molasses (HTM) were selected as suitable alternatives to more expensive, conventionally used growth medium additives. The optimization of CSL (6.4 g.l⁻¹) and HTM (24 g.l⁻¹) concentrations in the growth medium resulted in a 180% increase in cell concentration, a 5716-fold increase in cell productivity and a 97.2% decrease in the material cost of production in comparison to conventional growth conditions and parameters used at the onset of the study. In addition, a stable market-ready liquid probiotic product, encompassing the viable but not culturable (VBNC) state of Vibrio midae cells, was developed during the downstream processing aspect of the study. The demonstration of this technology at a full manufacturing scale has further enhanced the attractiveness and commercial feasibility of this production process.

Keywords: probiotics, abalone aquaculture, bioprocess technology, manufacturing scale technology development

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Authors: Claudio Díaz, Mabel Ortiz

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An EFL teacher education programme in Chile takes five years to train a future teacher of English. Preservice teachers are prepared to learn an advanced level of English and teach the language from 5th to 12th grade in the Chilean educational system. In the context of their first EFL Methodology course in year four, preservice teachers have to create a five-minute digital story that starts from a critical incident they have experienced as teachers-to-be during their observations or interventions in the schools. A critical incident can be defined as a happening, a specific incident or event either observed by them or involving them. The happening sparks their thinking and may make them subsequently think differently about the particular event. When they create their digital stories, preservice teachers put technology, teaching practice and theory together to narrate a story that is complemented by still images, moving images, text, sound effects and music. The story should be told as a personal narrative, which explains the critical incident. This presentation will focus on the creation process of 50 Chilean preservice teachers’ digital stories highlighting the critical incidents they started their stories. It will also unpack preservice teachers’ beliefs and reflections when approaching their teaching practices in schools. These beliefs will be coded and categorized through content analysis to evidence preservice teachers’ most rooted conceptions about English teaching and learning in Chilean schools. The findings seem to indicate that preservice teachers’ beliefs are strongly mediated by contextual and affective factors.

Keywords: beliefs, digital stories, preservice teachers, practicum

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Authors: Pablo Ampuero, Claudia Labarca

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The current research paper assesses how the narrative of Chilean businesspeople about China shapes a new Orientalism Analyses on the role of non-state actors in foreign policy that have hitherto theorized about Orientalism as a narrative of hegemonic power. Hence, it has been instrumental to the efforts of imperialist powers to justify their mission civilisatrice. However, such conceptualization can seldom explain new complexities of international interactions at the height of globalization. Hence, we assessed the case of Chile, a small Latin American country, and its relationship with China, its largest trading partner. Through a discourse analysis of interviews with Chilean businesspeople engaged in the Chinese market, we could determine that Chile is building an Orientalist image of China. This new business Orientalism reinforces a relation of alterity based on commercial opportunities, traditional values, and natural dispositions. Hence, the perception of the Chinese Other amongst Chilean business people frames a new set of representations as part of the essentially commercial nature of current bilateral relations. It differs from previous frames, such as the racial bias frame of the early 20^th century, or the anti-communist frame in reaction to Mao’s leadership. As in every narrative of alterity, there is not only a construction of the Other but also a definition of the Self. Consequently, this analysis constitutes a relevant case of the role of non-state actors in asymmetrical bilateral relations, where the non-state actors of the minor power build and act upon an Orientalist frame, which is not representative of its national status in the relation. This study emerges as a contribution on the relation amongst non-state actors in asymmetrical relations, where the smaller power’s business class acts on a negative prejudice of its interactions with its counterpart. The research builds upon the constructivist approach to international relations, linking the idea of Nation Branding with Orientalism in the case of Chile-China relations.

Keywords: new business Orientalism, small power, framing, Chile-China relations

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Authors: Selin Guney, Andres Riquelme

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The traditional bio-economic method for fisheries modeling uses some estimate of the growth parameters and the system carrying capacity from a biological model for the population dynamics (usually a logistic population growth model) which is then analyzed as a traditional production function. The stock dynamic is transformed into a revenue function and then compared with the extraction costs to estimate the maximum economic yield. In this paper, the logistic population growth model for the population is combined with a forecast of the abundance and location of the stock by using a generalized additive model approach. The paper focuses on the Chilean hake population. This method allows for the incorporation of climatic variables and the interaction with other marine species, which in turn will increase the reliability of the estimates and generate better extraction paths for different conservation objectives, such as the maximum biological yield or the maximum economic yield.

Keywords: bio-economic, fisheries, GAM, production

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Authors: Gaston Bacquet

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In light of existing social and structural violence in Chilean higher education which has resulted in instances of inequality, exclusion and discrimination, this research study attempted to provide trainee teachers in Chile with non-violent tools to deal with the tensions arising from these issues. Through a participatory action research design framed within a series of non-violent, non-Western perspectives, this study provided co-participants with opportunities to discuss current problems affecting HE in Chile stemming from the aforementioned violence, to think about strategies to address these and the challenges they might encounter. The study, which involved two different groups of trainee teachers from Chilean universities, consisted of two iterations of the action research cycle (planning – acting – observing – reflecting) carried out over two 3-months periods. Findings reveal instances of forced cultural assimilation, bullying, and direct and structural violence as key issues to address, and a strong individualistic mindset trumping collective well-being as the main challenge to bring non-violent strategies into their classrooms.

Keywords: non-violence education, contemplative pedagogy, participatory action research, dialogical education

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Authors: Sebastián Olivares Lizana, Marianna Oyanedel González

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This study takes part of a major project based on implementing a CLIL program (Content and Language Integrated Learning) at Universidad Técnica Federico Santa María, a leading Chilean tertiary Institution. It aims at examining the relationship between the development of Reflective Processes (RP) and Cognitive Academic Language Proficiency (CALP) in weekly learning logs written by faculty members, participants of an initial professional development online course on English for Academic Purposes (EAP). Such course was designed with a genre-based approach, and consists of multiple tasks directed to academic writing proficiency. The results of this analysis will be described and classified in a scale of key indicators that represent both the Reflective Processes and the advances in CALP, and that also consider linguistic proficiency and task progression. Such indicators will evidence affordances and constrains of using a genre-based approach in an EFL Engineering CLIL program implementation at tertiary level in Chile, and will serve as the starting point to the design of a professional development course directed to teaching methodologies in a CLIL EFL environment in Engineering education at Universidad Técnica Federico Santa María.

Keywords: EFL, EAL, genre, CLIL, engineering

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Authors: Gloria Toledo, Andrea Lizasoain, Leonardo Mena

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Immigration has largely increased in Chile in the last 20 years. About 6.6% of our population is foreign, from which 14.3% is Haitian. Haitians are between 15 and 29 years old and have come to Chile escaping from a social crisis. They believe that education and work will help them do better in life. Therefore, rates of Haitian students in the Chilean school system have also increased: there were 3,121 Haitian students enrolled in 2017. This is a challenge for the public school, which takes in young people who must face schooling, social immersion and learning of a second language simultaneously. The linguistic barrier affects both students’ and teachers’ adaptation process, which has an impact on the students’ academic performance and consequent acquisition of Spanish. In order to explore students’ academic performance and interlanguage development, we examined how L1 teachers assess Haitian high school students’ written production in Spanish. With this purpose, teachers were asked to use a specially designed grid to assess correction, accommodation, lexical and analytical complexity, organization and fluency of both Haitian and Chilean students. Parallelly, texts were approached from an error analysis perspective. Results from grids and error analysis were then compared. On the one hand, it has been found that teachers give very little feedback to students apart from scores and grades, which does not contribute to the development of the second language. On the other hand, error analysis has yielded that Haitian students are in a dynamic process of the acquisition of Spanish, which could be enhanced if L1 teacher were aware of the process of interlanguage developmen.

Keywords: assessment, error analysis, grid, immigration, Spanish aquisition, writing

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Authors: Cynthia Adlerstein

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Physical learning environment (PLE) has been considered, after family and educators, as the third teacher. There have been conflicting and converging viewpoints on the role of the physical dimensions of places to learn, in facilitating educational innovation and quality. Despite the different approaches, PLE has been widely recognized as a key factor in the quality of the learning experience , and in the levels of learning achievement in ECE . The conceptual frameworks of the field assume that PLE consists of a complex web of factors that shape the overall conditions for learning, and that much more interdisciplinary and complementary methodologies of research and development are required. Although the relevance of PLE attracts a broad international consensus, in Chile it remains under-researched and weakly regulated by public policy. Gaining deeper contextual understanding and more thoughtfully-designed recommendations require the use of innovative assessment tools that cross cultural and disciplinary boundaries to produce new hybrid approaches and improvements. When considering a PLE-based change process for ECE improvement, a central question is what dimensions, variables and indicators could allow a comprehensive assessment of PLE in Chilean kindergartens? Based on a grounded theory social justice inquiry, we adopted a mixed method design, that enabled a multivocal and interdisciplinary construction of data. By using in-depth interviews, discussion groups, questionnaires, and documental analysis, we elicited the PLE discourses of politicians, early childhood practitioners, experts in architectural design and ergonomics, ECE stakeholders, and 3 to 5 year olds. A constant comparison method enabled the construction of the dimensions, variables and indicators through which PLE assessment is possible. Subsequently, the instrument was applied in a sample of 125 early childhood classrooms, to test reliability (internal consistency) and validity (content and construct). As a result, an interdisciplinary and multivocal tool for assessing physical learning environments was constructed and validated, for Chilean kindergartens. The tool is structured upon 7 dimensions (wellbeing, flexible, empowerment, inclusiveness, symbolically meaningful, pedagogically intentioned, institutional management) 19 variables and 105 indicators that are assessed through observation and registration on a mobile app. The overall reliability of the instrument is .938 while the consistency of each dimension varies between .773 (inclusive) and .946 (symbolically meaningful). The validation process through expert opinion and factorial analysis (chi-square test) has shown that the dimensions of the assessment tool reflect the factors of physical learning environments. The constructed assessment tool for kindergartens highlights the significance of the physical environment in early childhood educational settings. The relevance of the instrument relies in its interdisciplinary approach to PLE and in its capability to guide innovative learning environments, based on educational habitability. Though further analysis are required for concurrent validation and standardization, the tool has been considered by practitioners and ECE stakeholders as an intuitive, accessible and remarkable instrument to arise awareness on PLE and on equitable distribution of learning opportunities.

Keywords: Chilean kindergartens, early childhood education, physical learning environment, third teacher

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Authors: G. Bravo, D. Lopez, A. Iriarte

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Several organizations and governments have created a demand for information about the environmental impacts of agricultural products. Today, the export oriented fruit sector in Chile is being challenged to quantify and reduce their environmental impacts. Chile is the largest southern hemisphere producer and exporter of sweet cherry fruit. Chilean sweet cherry production reached a volume of 80,000 tons in 2012. The main destination market for the Chilean cherry in 2012 was Asia (including Hong Kong and China), taking in 69% of exported volume. Another important market was the United States with 16% participation, followed by Latin America (7%) and Europe (6%). Concerning geographical distribution, the Chilean conventional cherry production is focused in the center-south area, between the regions of Maule and O’Higgins; both regions represent 81% of the planted surface. The Life Cycle Assessment (LCA) is widely accepted as one of the major methodologies for assessing environmental impacts of products or services. The LCA identifies the material, energy, material, and waste flows of a product or service, and their impact on the environment. There are scant studies that examine the impacts of sweet cherry cultivation, such as acidification and eutrophication. Within this context, the main objective of this study is to evaluate, using the LCA, the acidification and eutrophication impacts of sweet cherry production in Chile. The additional objective is to identify the agricultural inputs that contributed significantly to the impacts of this fruit. The system under study included all the life cycle stages from the cradle to the farm gate (harvested sweet cherry). The data of sweet cherry production correspond to nationwide representative practices and are based on technical-economic studies and field information obtained in several face-to-face interviews. The study takes into account the following agricultural inputs: fertilizers, pesticides, diesel consumption for agricultural operations, machinery and electricity for irrigation. The results indicated that the mineral fertilizers are the most important contributors to the acidification and eutrophication impacts of the sheet cherry cultivation. Improvement options are suggested for the hotspot in order to reduce the environmental impacts. The results allow planning and promoting low impacts procedures across fruit companies, as well as policymakers, and other stakeholders on the subject. In this context, this study is one of the first assessments of the environmental impacts of sweet cherry production. New field data or evaluation of other life cycle stages could further improve the knowledge on the impacts of this fruit. This study may contribute to environmental information in other countries where there is similar agricultural production for sweet cherry.

Keywords: acidification, eutrophication, life cycle assessment, sweet cherry production

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Authors: Marine Hascoet, Valentina Giaconi, Ludivine Jamain

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The aim of our study is to examine if the family socio-economic status (SES) has an influence on students’ academic achievement. We first make the hypothesis that the more their families have financial and social resources, the more students succeed at school. We second make the hypothesis that this family SES has also an impact on parents’ expectations about their children educational outcomes. Moreover, we want to study if that parents’ expectations play the role of mediator between parents’ socio-economic status and the student’ self-concept and academic outcome. We test this model with a longitudinal design thanks to the census-based assessment from the System of Measurement of the Quality of Education (SIMCE). The SIMCE tests aim to assess all the students attending to regular education in a defined level. The sample used in this study came from the SIMCE assessments done three times: in 4th, 8th and 11th grade during the years 2007, 2011 and 2014 respectively. It includes 156.619 students (75.084 boys and 81.535 girls) that had valid responses for the three years. The family socio-economic status was measured at the first assessment (in 4th grade). The parents’ educational expectations and the students’ self-concept were measured at the second assessment (in 8th grade). The achievement score was measured twice; once when children were in 4th grade and a second time when they were in 11th grade. To test our hypothesis, we have defined a structural equation model. We found that our model fit well the data (CFI = 0.96, TLI = 0.95, RMSEA = 0.05, SRMR = 0.05). Both family SES and prior achievements predict parents’ educational expectations and effect of SES is important in comparison to the other coefficients. These expectations predict students’ achievement three years later (with prior achievement controlled) but not their self-concept. Our model explains 51.9% of the achievement in the 11th grade. Our results confirm the importance of the parents’ expectations and the significant role of socio-economic status in students’ academic achievement in Chile.

Keywords: Chilean context, parent’s expectations, school achievement, self-concept, socio-economic status

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Authors: Oscar E. Cariceo

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In Chile, social workers´ professional training is developed in the undergraduate level, mainly. Despite the fact that several schools have been launched Master of Social Work programs, the Bachelor in Social Work is the minimum qualification to start a professional career. In the current Chilean higher education system, there exist different financial aid options in order to guarantee equal access to higher education. These policies, which are student loans and scholarships, basically, are applied and distributed by Government agencies. They are linked to academic performance and socio-economic needs, in terms of standardized test scores and social vulnerability criteria. In addition, institutions that enroll students with high scores, also receive direct financial support. In other words, social work students must compete for the resources to pay for college tuitions and fees with other students from different programs and knowledge fields and, as a consequence, they can indirectly enhance schools´ money income. This work aims to describe the reality of social work students to access to financial aid in Chile. The analysis presents the results of the University Selection Test of students, who were accepted in social work undergraduate programs during 2014 related to their qualifications to apply to three main financial aid programs, and their contribution to attracting resources to their schools. In general, data show that social work students participate in a low proportion in the distribution of financial aid, both student loans and scholarships. Few of them reach enough scores to guarantee direct financial resources to their institutions. Therefore, this situation has deep implications on equal access to higher education for vulnerable students and affects equal access to training options for young social workers, due to the highly competitive financial aid system.

Keywords: social work, professional training, higher education, financial aid, equity

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Authors: Viviana Letelier, Ester Tarela, Bianca Lopez, Pedro Muñoz, Giacomo Moriconi

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The environmental impact has become a global concern during the last decades. Several alternatives have been proposed and studied to minimize this impact in different areas. The reuse of aggregates from old concretes to manufacture new ones not only can reduce this impact but is also a way to optimize the resource management. The effect of the origin of the reused aggregates from two different origin materials in recycled concrete pavement is studied here. Using the dosing applied by a pavement company, coarse aggregates in the 6.3-25 mm fraction are replaced by recycled aggregates with two different origins: old concrete pavements with similar origin strength to the one of the control concrete, and precast concrete pipes with smaller strengths than the one of the control concrete. The replacement percentages tested are 30%, 40% and 50% in both cases. The compressive strength tests are performed after 7, 14, 28 and 90 curing days, the flexural strength tests and the elasticity modulus tests after 28 and 90 curing days. Results show that the influence of the quality of the origin concrete in the mechanical properties of recycled concretes is not despicable. Concretes with up to a 50% of recycled aggregates from the concrete pavement have similar compressive strengths to the ones of the control concrete and slightly smaller flexural strengths that, however, in all cases exceed the minimum of 5MPa after 28 curing days stablished by the Chilean regulation for pavement concretes. On the other hand, concretes with recycled aggregates from precast concrete pipes show significantly lower compressive strengths after 28 curing days. The differences with the compressive strength of the control concrete increase with the percentage of replacement, reaching a 13% reduction when 50% of the aggregates are replaced. The flexural strength also suffers significant reductions that increase with the percentage of replacement, only obeying the Chilean regulation when 30% of the aggregates are recycled after 28 curing days. Nevertheless, after 90 curing days, all series obey the regulation requirements. Results show, not only the importance of the quality of the origin concrete, but also the significance of the curing days, that may allow the use of less quality recycled material without important strength losses.

Keywords: flexural strength of recycled concrete., mechanical properties of recycled concrete, recycled aggregates, recycled concrete pavements

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Authors: María Graciela Aguayo, Laura Reyes, Claudia Oviedo, José Navarrete, Liset Gómez, Hugo Torres

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Most wood species used in construction deteriorate when exposed to environmental conditions that favor wood-degrading organisms’ growth. Therefore, chemical protection by impregnation allows more efficient use of forest resources extending the wood useful life. A wood protection treatment which has attracted considerable interest in the scientific community during the last decade is wood impregnation with nano compounds. Radiata pine is the main wood species used in the Chilean construction industry, with total availability of 8 million m³ sawn timber. According to the requirements of the American Wood Protection Association (AWPA) and the Chilean Standards (NCh) radiata pine timber used in construction must be protected due to its low natural durability. In this work, the impregnation with copper nanoparticles (CuNP) was studied in terms of penetration and its protective effect against wood rot fungi. Two concentrations: 1 and 3 g/L of NPCu were applied by impregnation on radiata pine sapwood. Test penetration under AWPA A3-91 standard was carried out, and wood decay tests were performed according to EN 113, with slight modifications. The results of penetration for 1 g/L CuNP showed an irregular total penetration, and the samples impregnated with 3 g/L showed a total penetration with uniform concentration (blue color in all cross sections). The impregnation wood mass losses due to fungal exposure were significantly reduced, regardless of the concentration of the solution or the fungus. In impregnated wood samples, exposure to G. trabeum resulted ML values of 2.70% and 1.19% for 1 g/L and 3 g/L CuNP, respectively, and exposure to P. placenta resulted in 4.02% and 0.70%-ML values for 1 g/L and 3 g/L CuNP, respectively. In this study, the penetration analysis confirmed a uniform distribution inside the wood, and both concentrations were effective against the tested fungi, giving mass loss values lower than 5%. Therefore, future research in wood preservatives should focus on new nanomaterials that are more efficient and environmentally friendly. Acknowledgments: CONICYT FONDEF IDeA I+D 2019, grant number ID19I10122.

Keywords: copper nanoparticles, fungal degradation, radiata pine wood, wood preservation

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Authors: Luz Hurtado, Rodrigo Rojas, Jaime Romero, Christopher Concha

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The culture of the marine fish red cusk eel Genypterus chilensis is currently considered a priority for Chilean aquaculture which is a Chilean native species of high gastronomic demand and market value. The microbiota was analyzed in terms of diversity and structure using massive Illumina sequencing. The analysis of alpha diversity was performed in samples of G. chilensis larvae of 6, 18 and 32 dph (days post-hatching) and it was observed that there were significant differences (P = 0.05) between the days of culture for the Chao1 index, being the larvae of 18 dph the one with the highest index followed by the larvae of 6 dph, The lowest value for this index was presented in larvae of 32 dph. There were no significant differences in larvae between the days of culture for the Shannon (P=0.0857) and Simpson (P=0.0714) indices. In general, the larvae of G. chilensis have high rates of diversity. When analyzing the beta diversity, a differentiation between the bacterial communities is observed depending on the day of the culture of the larvae. Considering the PCoA elaborated from the unweighted UniFrac statistic, the explained variance was 46.2% (PC1 29.2% and PC2 17.0%) and in the case of the PCoA elaborated with the weighted UniFrac statistic; the explained variance was 65.5% (PC1 41.8% and PC2 23.7%) these differences were significant based on the Permanova statistical analysis (P= 0.002 and 0.037 respectively). When analyzing the taxonomic composition of the microbiota of the larvae in the different days of culture it was observed that at the phyla level the most abundant in the larvae of 6 dph were Proteobacteria (57%) Verrucomicrobia (24%) and Firmicutes (14%), for the larvae of 18 dph the predominant phyla were Proteobacteria (90%), Dependientiae (5%), Actinobacteria (2%) and Plactomyces (2%), for the larvae of 32 dph the phyla that presented the highest relative abundance were Proteobacteria (57%), Firmicutes (29%), Verrucomicrobia (5%) and Actinobacteria (5%), when comparing the larvae between the days it was observed that the phylum Proteobacteria was the most abundant in the samples of larvae of 6, 18 and 32 dph being the larvae of 18 dph those that present the highest relative abundance, the larvae of 6 dph were those that presented the highest relative abundance for the phylum Verrucomicrobia and in the larvae of 32 dph was observed greater abundance of the phylum Firmicutes compared to the other days of larval culture. At the level of genera, those with the highest relative abundance in larvae of 6 dph were Rubritalea (30%), Psychrobacter (28%), staphylococcus (17%) and Ralstonia (10%), for the larvae of 18 dph the genera with the highest abundance were Psychrobacter (47%), Litoreibacter (13%), Nautella (9%) and Cohesibacter (8%), for the larvae of 32 dph the most abundant genera were Alloiococcus (25%), Dialister (14%), Neptunomonas (13%) and Piscirickettsia (11%). When observing the taxonomic composition of the larvae between the days of larval culture, it is observed that there are differences between them.

Keywords: microbiota, diversity, G. Chilensis, larvae

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Authors: Evelyn Ilabaca, Ximena Valenzuela, Alejandra Torres, María José Galotto, Abel Guarda

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One of the biggest problems in food packaging industry, especially with the plastic materials, is the fact that these materials are usually obtained from non-renewable resources and also remain as waste after its use, causing environmental issues. This is an international concern and particular attention is given to reduction, reuse and recycling strategies for decreasing the waste from plastic packaging industry. In general, polyethylenes represent most plastic waste and recycling process of post-consumer polyethylene terephthalate (PCR-PET) has been studied. US Food and Drug Administration (FDA), European Food Safety Authority (EFSA) and Southern Common Market (MERCOSUR) have generated different legislative documents to control the use of PCR-PET in the production of plastic packaging intended direct food contact in order to ensure the capacity of recycling process to remove possible contaminants that can migrate into food. Consequently, it is necessary to demonstrate by challenge test that the recycling process is able to remove specific contaminants, obtaining a safe recycled plastic to human health. These documents establish that the concentration limit for substitute contaminants in PET is 220 ppb (ug/kg) and the specific migration limit is 10 ppb (ug/kg) for each contaminant, in addition to assure the sensorial characteristics of food are not affected. Moreover, under the Commission Regulation (EU) N°10/2011 on plastic materials and articles intended to come into contact with food, it is established that overall migration limit is 10 mg of substances per 1 dm2 of surface area of the plastic material. Thus, the aim of this work is to determine the safety of PCR-PET-containing food packaging materials in Chile by measuring their overall migration, and their comparison with the established limits at international level. This information will serve as a basis to provide a regulation to control and regulate the use of recycled plastic materials in the manufacture of plastic packaging intended to be in direct contact with food. The methodology used involves a procedure according to EN-1186:2002 with some modifications. The food simulants used were ethanol 10 % (v/v) and acetic acid 3 % (v/v) as aqueous food simulants, and ethanol 95 % (v/v) and isooctane as substitutes of fatty food simulants. In this study, preliminary results showed that Chilean food packaging plastics with different PCR-PET percentages agree with the European Legislation for food aqueous character.

Keywords: contaminants, polyethylene terephthalate, plastic food packaging, recycling

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Authors: Andrés I. Ávila, Patricia Aros, César San Martín, Elizabeth Kehr, Yovana Leal

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We consider a linear programming model to help farmers to decide if it is convinient to choose among three kinds of export fruits for their future investment. We consider area, investment, water, productivitiy minimal unit, and harvest restrictions and a monthly based model to compute the average income in five years. Also, conditions on the field as area, water availability and initia investment are required. Using the Chilean costs and dollar-peso exchange rate, we can simulate several scenarios to understand the possible risks associated to this market.

Keywords: mixed integer problem, fruit production, support decision model, fruit tree farms

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Authors: Maria Barriga

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The article focuses on the analysis of three images of the last five years that represent different visions of social groups in the context of the so call “Conflicto Mapuche” in la Araucanía, Chile. Using a multimodal social semiotic approach, we analyze the meaning making of these images and the social groups strategies to achieve visibility and recognition in political contexts. We explore the making and appropriation of symbols and concepts and analyze the different strategies that groups use to built hegemonic views. Among these strategies, we compare the use of digital technologies in design these images and the influence of Chilean Estate's vision on the Mapuche political conflict. Finally, we propose visual strategies to improve basic conditions for dialogue and recognition among these groups.

Keywords: visual culture, power, conflict, indigenous people

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Authors: Oscar E. Cariceo

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In Chile, there is a lack of evidence about the impact of polyvictimization on the emergence of suicidal thoughts among children and young people. Thus, this study aims to explore the association between the episodes of polyvictimization suffered by Chilean children and young people and the manifestation of signs related to suicidal tendencies. To achieve this purpose, secondary data from the First Polyvictimization Survey on Children and Adolescents of 2017 were analyzed, and a binomial logistic regression model was applied to establish the probability that young people are experiencing suicidal ideation episodes. The main findings show that women between the ages of 13 and 15 years, who are in seventh grade and second in subsidized schools, are more likely to express suicidal ideas, which increases if they have suffered different types of victimization, particularly physical violence, psychological aggression, and sexual abuse.

Keywords: Chile, polyvictimization, suicidal ideation, youth

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Authors: Mabel Ortiz, Claudio Díaz

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This paper explores Chilean pre-service teachers' perceptions about the provision of corrective feedback in a wiki environment during the collaborative writing of an argumentative essay. After conducting a semi-structured interview on 22 participants, the data were processed through the content analysis technique. The results show that students have positive perceptions about corrective feedback, provided through a wiki virtual environment, which in turn facilitates feedback provision and impacts language learning effectively. Some of the positive perceptions about virtual feedback refer to permanent access, efficiency, simultaneous revision and immediacy. It would then be advisable to integrate wiki-based feedback as a methodology for the language classroom and collaborative writing tasks.

Keywords: argumentative essay, focused corrective feedback, perception, wiki environment

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Authors: Cynthia Adlerstein-Grimberg, Andrea Bralic-Echeverría

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An extensive and controversial research debate discusses pedagogical documentation (PD) within early childhood education (ECE) as integral to ECE teachers' professional development. The literature converges in acknowledging that ICT integration in PD can be fundamental for children's and teachers' collaborative learning by making their processes visible and open to reflection. Controversial issues about PD emerge around ICT integration and the use of multimedia applications and platforms, displacing the physical experience involved in this pedagogical practice. Authors argue that online platforms make PD become a passive device to demonstrate accountability and performance. Furthermore, ICT integration would make educators inform children and families of pedagogical processes, positioning them more as consumers instead of involving them in collective thinking and pedagogical decision-making. This article analyses how pedagogical documentation mediated by a multimedia application (MAFApp) allows for the positive strengthening of an ECE pedagogical online community that thinks collectively about learning environments. In doing so, the paper shows how ICT integration supports ECE teachers' collective online thinking, enabling them to move from the controversial version of online PD, where they only act as informers of children's learning and assume a voyeuristic perspective, towards a collective online thinking that builds professional development and supports pedagogical decision-making about learning environments. This article answers How ECE teachers' pedagogical documentation evolves with ICT integration using the MAFApp multimedia application in a national ECE online community. From a posthumanist stance, this paper draws on an 18-month collaborative ethnographic immersion in Chile's unique public ECE online PD community. It develops a unique case study of an online ECE pedagogical community mediated by a multimedia application called MAFApp. This ECE online community includes 32 Chilean public kindergartens, 45 ECE teachers, and 72 assistants, who produced 534 pedagogical documentation. Fieldwork included 35 in-depth interviews, 13 discussion groups, and the constant comparison method for the PD coding. Findings show ICT integration in PD builds collective online thinking that evolves through four moments of growing complexity: 1) teachernalism of built environments, 2) onlookerism of children's anecdotes in learning environments; 3) storytelling of children's place-making, and 4) empowering pedagogies for co-creating learning environments. ICT integration through the MAFApp multimedia application enabled ECE teachers to build collective online thinking, making pedagogies of place visible and engaging children in co-constructing learning environments. This online PD is a continuous professional learning space for ECE teachers, empowering pedagogies of place. In conclusion, ICT integration into PD progressively empowers pedagogies of place in Chilean public ECE. Strengthening collective online thinking using the MAFApp multimedia application sharply contrasts with some recent PD research findings. ICT integration to PD enabled strong collective online thinking. Doing so makes PD operate as a place of professional development, pedagogical reflective encounters, and experimentation while inhabiting their own learning environments with children.

Keywords: early childhood education, ICT integration, multimedia application, online collective thinking, pedagogical documentation, professional development

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Authors: Andrés I. Ávila, Patricia Aros, César San Martín, Elizabeth Kehr, Yovana Leal

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Planning models for fresh products is a very useful tool for improving the net profits. To get an efficient supply chain model, several functions should be considered to get a complete simulation of several operational units. We consider a linear programming model to help farmers to decide if it is convenient to choose what area should be planted for three kinds of export fruits considering their future investment. We consider area, investment, water, productivity minimal unit, and harvest restrictions to develop a monthly based model to compute the average income in five years. Also, conditions on the field as area, water availability, and initial investment are required. Using the Chilean costs and dollar-peso exchange rate, we can simulate several scenarios to understand the possible risks associated to this market. Also, this tool help to support decisions for government and individual farmers.

Keywords: mixed integer problem, fresh fruit production, support decision model, agricultural and biosystems engineering

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Authors: Eva Wagner, Lucely Vargas

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Corporate Social Responsibility (CSR) plays an important role in (large-scale) enterprises’ business strategy in developed and emerging countries. This article approaches CSR in international comparison by examining the CSR reporting of 116 leading companies in Austria, Germany, Colombia and Chile from 2006 to 2010. We have used an independently developed scoring model which analyzes reported CSR-activities using seven dimensions to efficiently assess CSR. The study reveals that there are significant differences in CSR-commitment among countries and regions: German companies, as expected, lead most of the investigated CSR dimensions revealing stronger commitment to CSR than their Austrian, Colombian and Chilean counterparts. Even if Latin American companies lag behind their European counterparts, they exhibit high CSR-performance in the social dimension: corporate giving and philanthropic activities are firmly anchored in the tradition of Latin American companies. This indicates that particular CSR-emphases reflect the political and social circumstances of each individual country.

Keywords: corporate social responsibility, corporate social performance, international comparison

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Authors: Carolina Busco, Daniela Osses

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The development of digital literacy has become a fundamental element that allows for citizen inclusion, access to quality jobs, and a labor market capable of responding to the digital economy. There are no methodological instruments available in Chile to measure the workforce’s digital literacy and improve national policies on this matter. Thus, the objective of this research is to develop a survey to measure digital literacy in a sample of 200 Chilean workers. Dimensions considered in the instrument are sociodemographics, access to infrastructure, digital education, digital skills, and the ability to use e-government services. To achieve the research objective of developing a digital literacy model of indicators and a research instrument for this purpose, along with an exploratory analysis of data using factor analysis, we used an empirical, quantitative-qualitative, exploratory, non-probabilistic, and cross-sectional research design. The research instrument is a survey created to measure variables that make up the conceptual map prepared from the bibliographic review. Before applying the survey, a pilot test was implemented, resulting in several adjustments to the phrasing of some items. A validation test was also applied using six experts, including their observations on the final instrument. The survey contained 49 items that were further divided into three sets of questions: sociodemographic data; a Likert scale of four values ranked according to the level of agreement; iii) multiple choice questions complementing the dimensions. Data collection occurred between January and March 2022. For the factor analysis, we used the answers to 12 items with the Likert scale. KMO showed a value of 0.626, indicating a medium level of correlation, whereas Bartlett’s test yielded a significance value of less than 0.05 and a Cronbach’s Alpha of 0.618. Taking all factor selection criteria into account, we decided to include and analyze four factors that together explain 53.48% of the accumulated variance. We identified the following factors: i) access to infrastructure and opportunities to develop digital skills at the workplace or educational establishment (15.57%), ii) ability to solve everyday problems using digital tools (14.89%), iii) online tools used to stay connected with others (11.94%), and iv) residential Internet access and speed (11%). Quantitative results were discussed within six focus groups using heterogenic selection criteria related to the most relevant variables identified in the statistical analysis: upper-class school students; middle-class university students; Ph.D. professors; low-income working women, elderly individuals, and a group of rural workers. The digital divide and its social and economic correlations are evident in the results of this research. In Chile, the items that explain the acquisition of digital tools focus on access to infrastructure, which ultimately puts the first filter on the development of digital skills. Therefore, as expressed in the literature review, the advance of these skills is radically different when sociodemographic variables are considered. This increases socioeconomic distances and exclusion criteria, putting those who do not have these skills at a disadvantage and forcing them to seek the assistance of others.

Keywords: digital literacy, digital society, workforce digitalization, digital skills

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Authors: Carolina Cuéllar, Paz González

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Research has shown that school leadership has a significant indirect effect on students’ achievements. In Chile, evidence has also revealed that this impact is stronger in vulnerable schools. With the aim of strengthening school leadership, public policy has taken up the challenge of enhancing capabilities of novice principals through the implementation of induction programs, which include a mentoring component, entrusting the task of delivering these programs to universities. The importance of using mentoring or coaching models in the preparation of novice school leaders has been emphasized in the international literature. Thus, it can be affirmed that building leadership capacity through partnership is crucial to facilitate cognitive and affective support required in the initial phase of the principal career, gain role clarification and socialization in context, stimulate reflective leadership practice, among others. In Chile, mentoring is a recent phenomenon in the field of school leadership and it is even more new in the preparation of new principals who work in public schools. This study, funded by the Chilean Ministry of Education, sought to explore the challenges and lessons arising from the design and implementation of mentoring processes which are part of the induction programs, according to the perception of the different actors involved: ministerial agents, university coordinators, mentors and novice principals. The investigation used a qualitative design, based on a study of three cases (three induction programs). The sources of information were 46 semi-structured interviews, applied in two moments (at the beginning and end of mentoring). Content analysis technique was employed. Data focused on the uniqueness of each case and the commonalities within the cases. Five main challenges and lessons emerged in the design and implementation of mentoring within the induction programs for new principals from Chilean public schools. They comprised the need of (i) developing a shared conceptual framework on mentoring among the institutions and actors involved, which helps align the expectations for the mentoring component within the induction programs, along with assisting in establishing a theory of action of mentoring that is relevant to the public school context; (ii) recognizing trough actions and decisions at different levels that the role of a mentor differs from the role of a principal, which challenge the idea that an effective principal will always be an effective mentor; iii) improving mentors’ selection and preparation processes trough the definition of common guiding criteria to ensure that a mentor takes responsibility for developing critical judgment of novice principals, which implies not limiting the mentor’s actions to assist in the compliance of prescriptive practices and standards; (iv) generating common evaluative models with goals, instruments and indicators consistent with the characteristics of mentoring processes, which helps to assess expected results and impact; and (v) including the design of a mentoring structure as an outcome of the induction programs, which helps sustain mentoring within schools as a collective professional development practice. Results showcased interwoven elements that entail continuous negotiations at different levels. Taking action will contribute to policy efforts aimed at professionalizing the leadership role in public schools.

Keywords: induction programs, mentoring, novice principals, school leadership preparation

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Authors: Julio Lavarello-Salinas, Verónica Kramm-Vergara, Pedro Gil-La Orden

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During the COVID-19 pandemic, mental health became a relevant factor in people’s performance within organizations. The aim of this study was to analyze the effects of an organizational intervention program on the psychosocial factors of demands, resources, and the consequences of psychosocial risks in a technology services company during the COVID-19 pandemic. A quasi-experimental study was carried out with 105 employees who took part in an eight-week intervention program divided into two large stages. Pre- and post- measurements were collected using the UNIPSICO Questionnaire, considering its factors of demands, resources, and consequences of psychosocial risks. The Spanish Burnout Inventory (SBI) was also included. The results showed significant improvements in the perception of some psychosocial demand factors, all the resource factors, and all the consequences of psychosocial risks, except the guilt dimension of the SBI. Thus, we can conclude that the program was effective and that the study limitations should be improved in future studies.

Keywords: UNIPSICO questionnaire, occupational health, work stress, work psychosocial risk

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