El programa ECBI y su impacto en los sextos básicos de la Escuela Villa Culenar de Talca

30 p.El presente trabajo da a conocer los principales aspectos de la metodología ECBI (Enseñanza de las Ciencias Basada en la Indagación) y de qué manera al ser implementada en uno de los sextos años básicos de la Escuela Villa Culenar de Talca se obtienen mejores aprendizajes en los alumnos y alumnas en comparación con el otro curso paralelo. El objetivo del presente trabajo de graduación es demostrar el impacto que tiene el Programa ECBI en los estudiantes de los sextos años básicos en relación a mejorar los aprendizajes de éstos en la asignatura de Ciencias Naturales. La metodología utilizada se basó en la contrastación de resultados según rendimiento de los alumnos de los sextos años tomando en cuenta al Sexto año A como grupo experimental y al Sexto año B como grupo control. Los resultados obtenidos comprueban que el curso en que se implementó el Programa ECBI mejoró los aprendizajes en comparación con el curso control todo ello demostrado en el mayor interés por las Ciencias y mejores calificaciones de los estudiantes

Efecto del reemplazo de la vegetación nativa de ribera sobre la comunidad de macroinvertebrados bentónicos en arroyos de climas templados, Chile central

The organic matter from riparian vegetation is determined by the structure and complexity of streams. It presents a higher energetic input to streams as well as important source of food for macroinvertebrates in head streams. In spite of its importance, riparian landscape has been rapidly degraded by human activity, this affects structure and composition of the aquatic community. The present study was made in Central Chile (Biobio Region) which has intensive forest activity with exotic species. Small streams were selected (< 3 order), because they are very particularly sensitive to changes in land use. The sites were grouped identified according to native forest land cover larger than 20% (group 1) and smaller than 20% (group 2). Significant differences (p?< 0.05) in Plecoptera abundance (p<0.05) were found between the two groups. Differences in trophic groups were significant for shredders and predators increased and gathering-collectors decreased their abundance, with native cover smaller than 20%. This showed the dependent on allochthonous material. The vegetation cover and community parameters correlations showed that Diversity (H?) increased with higher percentage of watershed covered by native vegetation and exotic species mix. Results suggest that a buffer conservation area of native riparian vegetation is necessary in streams and rivers in order to maintain the structure and diversity of macroinvertebrates and health of these ecosystems.El aporte de materia orgánica desde la vegetación ribereña es determinante en la estructura y complejidad de los sistemas fluviales; es identificado como el mayor aporte energético en ríos y una fuente importante de alimento para macroinvertebrados en arroyos de cabecera. No obstante, el paisaje ribereño ha sido altamente degradado por actividades humanas, lo que ha afectado la estructura y composición de las comunidades acuáticas. El presente estudio se desarrolló en Chile central (región del Biobío) donde se concentra una intensa actividad forestal con especies exóticas. Se seleccionaron ríos de bajo orden (< 3), por su sensibilidad al cambio de uso del suelo, los cuales fueron clasificados de acuerdo a la cobertura de bosque nativo como mayor al 20% (grupo 1) y menor al 20% (grupo 2). La comparación de los macroinvertebrados según esta clasificación mostró una abundancia significativamente menor (p< 0.05) de Plecoptera en sitios con menos vegetación nativa. Al comparar los grupos tróficos funcionales, hubo diferencias significativas (p?<0.05) para los fragmentadores y los depredadores quienes disminuyeron su abundancia, mientras que los detritívoros aumentaron, lo que demuestra su dependencia del aporte alóctono. Las correlaciones entre el porcentaje de cobertura vegetal y los parámetros comunitarios de macroinvertebrados destacó la correlación entre la Diversidad (H?) y la mezcla de bosque nativo y especies exóticas (r =0.91). Los resultados sugieren la necesidad de conservar un área amortiguadora con vegetación ribereña nativa en arroyos y ríos, que permita mantener la estructura y diversidad de las comunidades y con ello, el estado de salud de estos ecosistemas

Transcriptome analysis and postharvest behavior of the kiwifruit `Actinidia deliciosa¿ reveal the role of ethylene-related phytohormones during fruit ripening

Kiwifruit are climacteric fruit, so they must be harvested before they are fully ripe, allowing for the extension of their shelf-life via cold storage. Therefore, an adequate knowledge about how ethylene-induced fruit senescence is required to avoid significant economic losses. The main goal of the present study was to investigate the kiwifruit ripening process at the physiological and molecular levels by RNA-seq after 1-methylcyclopropene (1-MCP, ethylene inhibitor) and Ethrel® (ethylene stimulator) treatments. The results showed that Ethrel® (ethephon) treatment induced more accelerated fruit ripening, leading to rapid fruit senescence, meanwhile 1-MCP caused a slowing flesh softening, and thus a longer shelf-life period. The RNA-seq was carried out on the fruit after 4 and 13 days, considering day 4 as the most determinant in terms of differentially expressed genes (DEGs). The sequencing achieved 70.7% alignment with the `Hongyang¿ genome, obtaining 18,036 DEGs. The protein-protein interaction (PPI) network shows the interaction between different pathways in two main clusters: (1) pentose and glucoronate interconversions, citrate cycle, glycolysis and gluconeogenesis or starch, and sucrose metabolism and (2) porphyrin and chlorophyll metabolism. The first cluster is mainly interconnected by G6PD1 (pentose pathway); E1 ALPHA and ACLB-2 (citrate cycle); Achn209711 (pentose and glucoronate); LOS2 (glycolysis); HKL1 and HXK1 (glycolysis¿starch and sucrose); and PHS2 (starch and sucrose). In the second cluster, GUN5 through PORA is interacting with CRD1 and NYC1 which were overexpressed by 1-MCP in the porphyrin and chlorophyll metabolism. In addition, genes linked to PSBY and PSBP photosynthesis-linked proteins in photosystem 2 were overexpressed by 1-MCP which is undoubtedly related to chlorophyll degradation and fruit senescence. These results suggest that in kiwifruit, the main pathways that are regulated by ethylene-induced senescence comprise sugar catabolism and chlorophyll degradation.The authors would like to thank the National Commission for Scientific and Technological Research (CONICYT) of Chile government through the project FONDEF N° D09i-1136. Additionally, we thank the Seneca Foundation in the region of Murcia (Spain) through the Regional subprogram “Saavedra Fajardo” (20397/ SF/17) and Ministry of Science and Innovation through the project “Juan de la Cierva Incorporación” N° IJC2018-0366-

Results of the first European Source Apportionment intercomparison for Receptor and Chemical Transport Models

In this study, the performance of the source apportionment model applications were evaluated by comparing the model results provided by 44 participants adopting a methodology based on performance indicators: z-scores and RMSEu, with pre-established acceptability criteria. Involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), provided a unique opportunity to cross-validate them. In addition, comparing the modelled source chemical profiles, with those measured directly at the source contributed to corroborate the chemical profile of the tested model results. The most used RM was EPA- PMF5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) and more difficulties are observed with SCE time series (72% of RMSEu accepted). Industry resulted the most problematic source for RMs due to the high variability among participants. Also the results obtained with CTMs were quite comparable to their ensemble reference using all models for the overall average (>92% of successful z-scores) while the comparability of the time series is more problematic (between 58% and 77% of the candidates’ RMSEu are accepted). In the CTM models a gap was observed between the sum of source contributions and the gravimetric PM10 mass likely due to PM underestimation in the base case. Interestingly, when only the tagged species CTM results were used in the reference, the differences between the two CTM approaches (brute force and tagged species) were evident. In this case the percentage of candidates passing the z-score and RMSEu tests were only 50% and 86%, respectively. CTMs showed good comparability with RMs for the overall dataset (83% of the z-scores accepted), more differences were observed when dealing with the time series of the single source categories. In this case the share of successful RMSEu was in the range 25% - 34%.JRC.C.5-Air and Climat

The Population Decline and Extinction of Darwin's Frogs

Darwin's frogs (Rhinoderma darwinii and R. rufum) are two species of mouth-brooding frogs from Chile and Argentina. Here, we present evidence on the extent of declines, current distribution and conservation status of Rhinoderma spp.; including information on abundance, habitat and threats to extant Darwin's frog populations. All known archived Rhinoderma specimens were examined in museums in North America, Europe and South America. Extensive surveys were carried out throughout the historical ranges of R. rufum and R. darwinii from 2008 to 2012. Literature review and location data of 2,244 archived specimens were used to develop historical distribution maps for Rhinoderma spp. Based on records of sightings, optimal linear estimation was used to estimate whether R. rufum can be considered extinct. No extant R. rufum was found and our modelling inferred that this species became extinct in 1982 (95% CI, 1980-2000). Rhinoderma darwinii was found in 36 sites. All populations were within native forest and abundance was highest in Chiloé Island, when compared with Coast, Andes and South populations. Estimated population size and density (five populations) averaged 33.2 frogs/population (range, 10.2-56.3) and 14.9 frogs/100 m(2) (range, 5.3-74.1), respectively. Our results provide further evidence that R. rufum is extinct and indicate that R. darwinii has declined to a much greater degree than previously recognised. Although this species can still be found across a large part of its historical range, remaining populations are small and severely fragmented. Conservation efforts for R. darwinii should be stepped up and the species re-classified as Endangered

Influencia de las redes sociales en la creación y mantención del capital social en Chile

Seminario para optar al grado de Ingeniero Comercial, Mención AdministraciónNo autorizada por los autores para ser publicada a texto completoEl presente trabajo se replicó el estudio realizado por Ellison , Steinfield y Lampe (2007) sobre el uso de redes sociales y su influencia dentro del capital social. Este estudio original se centro en estudiar alumnos de la Universidad de Michigan, Estados Unidos, en su uso de Facebook y la influencia que tuvo en la mantención y creación del capital social de estos individuos. En este estudio se buscó testear las mismas hipótesis del trabajo original pero ahora adaptadas en la realidad social de Chile, utilizando una muestra de 546 alumnos de 1 a 5 año de la Facultad de Economía y Negocios de la Universidad de Chile. Para obtener respuestas más precisas en esta oportunidad se ampliaron las redes sociales investigadas, a Facebook ya analizada en el trabajo original, se le agregaron las redes sociales con mayor crecimiento durante el ultimo tiempo: Twitter y LinkedIn. Al testear, analizar, tabular y realizar regresiones a los resultados de la encuesta realizada, se tuvo resultados similares al trabajo original, inclusive en el caso de Facebook se vio mucho más potenciada. En las otras dos redes sociales también se cumplió la hipótesis generada, pero con una menor intensidad. Estos resultados terminan siendo consistentes con los encontrados en el trabajo original del cual se basa este informe. El estudio muestra que el uso de las redes sociales afecta positivamente a mantener y crear los distintos tipos de capital social (ya sea puente o vínculo), junto con los índices de felicidad tales como la satisfacción con la vida universitaria y el grado de autoestima

Response of sink manipulation in ?Lapins? sweet cherry (Prunus avium L.) branches to late-deficit irrigation

Photosynthetic traits, leaf soluble sugars and fruit yield and size were evaluated in order to identify the role of early sink manipulation (girdling and fruiting spur thinning applied in winter) in modulating the effect of latedeficit irrigation (recovering 60% of crop evapotranspiration during 36 days pre harvest) in 'Lapins' sweet cherry branches. Photosynthesis (PN), stomatal conductance (gs), and fruit weight were affected by both treatments, whereas intercellular CO2 concentration of leaves (Ci), mesophyll conductance (gm), Rubisco carboxylase activity (Vcmax), electron transport rate (Jmax), leaf soluble sugars and branch yield were exclusively affected by sink manipulation. The effect of sink manipulation on PN was mainly observed in the girdling treatment as it was not altered by thinning. In girdled branches, PN dropped by 34%, accompanied by a two fold increase in leaf soluble sugars, indicating that sink feedback regulation of carbon assimilation occurred. Irrespective of the irrigation, the higher PN observed in the controls were not sufficient to achieve the fruit weight and yield of the girdled branches, indicating that fruit carbon demand in control branches was source limited. The depressed PN by girdling was associated with significant reductions in gs, gm, Vcmax and Jmax. Since lowered PN by deficit irrigation was neither attributable to a gs associated decrease in Ci nor to changes in any other photosynthetic variable, further research is needed to clarify this point. Results showed that irrigation deficit was sufficient to reduce PN in girdled branches, whereas it had no effect in control and thinned branches. Thus, the depressive effect of deficit irrigation on PN appeared to be exacerbated by the sink effect

Different alternatives for producing sprouts of avocado (Persea americana) rootstocks

In Chile, most avocado orchards have been planted using 'Hass' as the scion variety on seedling rootstocks. This has led to the presence of a large variety of individuals, some of which show, among other characteristics, high productivity and a low degree of biennial bearing cycle in the same growing conditions. The most common method used in other countries to propagate such rootstocks from trees involves severe topping; however, this technique is notably destructive, making it difficult to employ in commercial orchards. With the goal of developing alternate methods for forcing shoot production from the rootstock, we tested two different procedures in July 2002 and March 2003, respectively: wounding in conjunction with the application of 1.1 M or 2.2 M benzylaminopurine (BAP) and the removal of one half of the tree canopy (on a vertical plane) and girdling (at widths of 2 or 5 mm). The results indicate that, by removing the top layer of the soil, wounding and applying the BAP spray (1.1 M in July), it is possible to force the production of epicormic or basal sprouting from the rootstock. Additionally, vigorous shoots were obtained on both evaluation dates through the removal of half of the canopy or through girdling.En Chile, la mayoría de los huertos de palto (Persea americana Mill.) sobre los cuales se encuentra el injerto 'Hass' están sobre portainjertos provenientes de semilla. La influencia de las características propias del portainjerto ha dado como resultado la existencia de una amplia variedad de individuos con distintos niveles de producción y alternancia en iguales condiciones de crecimiento. En otros países, se han desarrollado técnicas como la poda completa del árbol para la clonación de portainjetos, sin embargo esta técnica es altamente destructiva y difícil de implementar en huertos comerciales. Por esta razón se desarrolló una metodología, con el objetivo de obtener brotación de brotes epicórmicos o renuevos basales desde el portainjerto, en dos épocas distintas (julio y marzo, durante los años 2002 y 2003, respectivamente), a través del lesionado y la aplicación de bencilaminopurina (BAP) en dos concentraciones (1,1 y 2,2 M) y rebaje parcial del árbol y anillado (de 2 y 5 mm). Los resultados obtenidos mostraron que mediante el lesionado y aplicación de BAP 1,1 M en julio, se obtuvieron brotes epicórmicos o basales desde la zona del portainjerto; al podar parcialmente el árbol; y que al anillar se logra obtener brotes vigorosos en ambas épocas de evaluación

Antarctic Streptomyces fildesensis So13.3 strain as a promising source for antimicrobials discovery

Antarctic have been suggested as an attractive source for antibiotics discovery and members of Streptomyces genus have historically been studied as natural producers of antimicrobial metabolites. Nonetheless, our knowledge on antibiotic-producing Streptomyces from Antarctic is very limited. In this study, the antimicrobial activity of organic extracts from Antarctic Streptomyces strains was evaluated by disk diffusion assays and minimum inhibitory concentration. The strain Streptomyces sp. So13.3 showed the greatest antibiotic activity (MIC = 15.6 μg/mL) against Gram-positive bacteria and growth reduction of Gram‒negative pathogens. The bioactive fraction in the crude extract was revealed by TLC‒bioautography at Rf = 0.78 with molecular weight between 148 and 624 m/z detected by LC-ESI-MS/MS. The strain So13.3 was taxonomically affiliated as Streptomyces fildesensis. Whole genome sequencing and analysis suggested a 9.47 Mb genome size with 42 predicted biosynthetic gene clusters (BGCs) and 56 putative clusters representing a 22% of total genome content. Interestingly, a large number of them (11 of 42 BGCs and 40 of 56 putative BGCs), did not show similarities with other known BGCs. Our results highlight the potential of the Antarctic Streptomyces strains as a promising source of novel antimicrobials, particularly the strain Streptomyces fildesensis So13.3, which first draft genome is reported in this work

High School Students’ Affective Reaction to English Speaking Activities

This study aims to measure fifty-two high school students’ affective reactions after doing individual and pair-based speaking activities then completing a semantic differential scale of nine bipolar adjectives. Results do not show significant statistical differences between the two types of activities or the schools involved in this study, but participants from both schools present a similar affective reaction towards individual and pair-based speaking activities