Corroborating students’ self-reports of source evaluation

Students were asked to report their typical practices with regard to source evaluation using the Credibility Assessment Scale (CAS). Students’ reports were validated against behavioural and cognitive indicators of source evaluation. Specifically, while researching a social science prompt, students’ source use behaviours, related to text evaluation, were logged. Following task completion, students were asked to rank the trustworthiness of the information sources they accessed and to justify their rankings. The criteria students cited for rankings of text trustworthiness were considered to be cognitive-based indicators of source evaluation, and mapped onto CAS items. Limited correspondence was found between students’ reported engagement in verification-related behaviours and either the behaviours manifest during task completion or the criteria for source evaluation cited at post-task. At the same time, a correspondence was found among behavioural and cognitive aspects of source evaluation, within the context of a specific task. This study is unique in directly corroborating self-reported, behavioural, and cognitive measures of source evaluation and examining these within the context of a rich and naturalistic multiple text task. Implications for research and practice are discussed.     

Landscape integration of North Patagonian mountain lakes: a first approach using characterization of dissolved organic matter

North‐western Patagonia contains a variety of glacially formed mountain lakes located at different positions from the treeline in the Andean Patagonian forest region. Water chemistry of six North Patagonian lakes located in an altitudinal gradient, above, at and below the treeline (~41°S) were analysed in this study. The relative importance of allochtonous to autochthonous carbon inputs along a marked catchment vegetation gradient encompassing altoandino vegetation and Nothofagus forests was addressed. The dissolved organic carbon (DOC) concentration varied among the study lakes, with the lakes located higher in the landscape exhibiting lower DOC concentrations (<1 mg L^?1) than lakes located at or below the treeline (>2 mg L^?1). Analysis of coloured and fluorescent dissolved organic matter (CDOM and FDOM, respectively) followed the DOC pattern, despite the contrasting catchments of the study lakes. The results indicated the CDOM in all the lakes had low molecular weight and low aromaticity. The excitation–emission matrices (EEMs) highlighted three distinctive fluorophores in the FDOM, including two humic‐like (peak A and peak C) revealing the presence of humic terrestrial material, and a protein‐like fluorophore (peak T) generally associated with autochthonous DOM. The increased intensities of the humic fluorophores in the lakes located below the treeline suggest higher allochtonous carbon inputs from their catchments. This evidence collectively suggests that mountain lakes exhibit some heterogeneity in terms of DOM, likely attributable to their position in relation to the treeline, which determines the contribution of the catchment. As remote lakes are extremely sensitive to changes in their catchments, these North Patagonian mountain lakes may accurately track the impact of climate and anthropogenic changes on the landscape.     

Experimental investigation of the effect of residual stresses and interfacial adhesion on rapid crack propagation in bilayered polypropylene/polyethylene (PP/PE100) pipes

Rapid crack propagation (RCP) resistance of bilayered pipes consisting of a polyethylene core and a polypropylene skin was investigated using the ISO 13477 Small Scale Steady State “S4” test. It was found that bilayered pipes met all the RCP requirements, but the addition of a thin (0.4–1.5 mm) skin slightly increased the S4 critical temperature. This embrittlement effect is attributed to increased constraint, which is mainly influenced by the elastic moduli of the skin and core and the adhesion between them. Because the elastic moduli of the skins were very similar, the investigation focused on the effect of adhesion and residual stresses. It was found that higher adhesion leads to higher constraint and higher S4 critical temperature. However, when both adhesion and residual stresses were modified during annealing, the effect of residual stress relaxation was more significant on RCP performance than that of increasing adhesion. Annealed pipes in which residual stresses had relaxed by ～40%, showed better RCP resistance even though adhesion was almost doubled. It was found that in some cases, bilayered pipes may even present better RCP resistance than monolayered ones when the adhesion falls below a threshold at which the skin no longer constrains the pipe. POLYM. ENG. SCI., 57:458–463, 2017. © 2016 Society of Plastics Engineers     

Quantification and Determination of Composition of Steryl Ferulates in Refined Rice Bran Oils Using an UPLC-MS Method

Gamma-oryzanol contains a mixture of steryl ferulates found in rice bran oil. Several studies have attributed nutraceutical properties to this mixture, such as hypocholesterolemic and anti-inflammatory activities. A method based on ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry was developed and evaluated for the simultaneous quantification of gamma-oryzanol and identification of five major steryl ferulates directly in refined rice bran oils (RBO) samples. The proposed method was evaluated according to linearity by obtaining standard curves with R ² values above 0.990, and limit of detection values ranged from 1.9 to 5.9 µg/mL, whereas limits of quantification ranged from 5.9 to 17.9 µg/mL; inter- and intraday accuracy and precision were within the range required by the US Food and Drug Administration guidelines; recovery levels ranged from 78 to 85% for gamma-oryzanol, and from 84 to 119% for steryl ferulates. The method can be considered robust in relation to the NH₄OH (ammonium hydroxide) content and cone voltage variations, with coefficient of variation and average relative percentage deviation values lower than 7.0 and 4.4%, respectively. The stability during the storage test was maintained in concentrated samples (18.5 µg/mL), with recovered values between 93 and 113%. This method was successfully applied to the analysis of RBO samples, demonstrating that it could be easily used for quality control purposes.     

Volatile-Mediated Interactions between Cabbage Plants in the Field and the Impact of Ozone Pollution

Plants constitutively release volatile organic compounds (VOCs), but qualitatively and quantitatively alter their emission of VOCs in response to biotic and abiotic stresses. The blend of VOCs emitted reflects the physiological status of the plant. Plants may be exposed to the VOC blend emitted by their near neighbors and gain information that allows them to adjust their own defenses. These plant-plant interactions may potentially be exploited to protect crops from pests, but they can be disturbed by abiotic factors making the process sensitive to environmental perturbation. Despite numerous studies describing plant-plant interactions, relatively few have been conducted with agriculturally significant cultivated plant varieties under field conditions. Here we studied plant-plant interactions in a conspecific association of Brassica oleracea var. capitata (cabbage) and show that undamaged plants exposed to neighbors damaged by the herbivore Pieris brassicae are primed for stronger volatile emissions upon subsequent herbivore attack. We conducted a field study in an ozone free-air concentration enrichment (FACE) facility with ambient and elevated ozone levels and found that elevated tropospheric ozone significantly alters the priming of VOCs in receiver plants. We conclude that plant-plant interactions may prime defensive attributes of receiver plants under field conditions, but are impaired by ozone pollution. Therefore, when planning the manipulation of plant-plant interactions for agricultural purposes, the potential effects of atmospheric pollutants should be considered.     

A school-based intervention improved dietary intake outcomes and reduced waist circumference in adolescents: a cluster randomized controlled trial

Background

In Ecuador, adolescents’ food intake does not comply with guidelines for a healthy diet. Together with abdominal obesity adolescent’s inadequate diets are risk factors for non-communicable diseases. We report the effectiveness of a school-based intervention on the dietary intake and waist circumference among Ecuadorian adolescents.

Methods

A pair-matched cluster randomized controlled trial including 1430 adolescents (12–14 years old) was conducted. The program aimed at improving the nutritional value of dietary intake, physical activity (primary outcomes), body mass index, waist circumference and blood pressure (secondary outcomes). This paper reports: (i) the effect on fruit and vegetable intake, added sugar intake, unhealthy snacking (consumption of unhealthy food items that are not in line with the dietary guidelines eaten during snack time; i.e. table sugar, sweets, salty snacks, fast food, soft drinks and packaged food), breakfast intake and waist circumference; and, (ii) dose and reach of the intervention. Dietary outcomes were estimated by means of two 24-h recall at baseline, after the first 17-months (stage one) and after the last 11-months (stage two) of implementation. Dose and reach were evaluated using field notes and attendance forms. Educational toolkits and healthy eating workshops with parents and food kiosks staff in the schools were implemented in two different stages. The overall effect was assessed using linear mixed models and regression spline mixed effect models were applied to evaluate the effect after each stage.

Results

Data from 1046 adolescents in 20 schools were analyzed. Participants from the intervention group consumed lower quantities of unhealthy snacks (?23.32 g; 95% CI: ?45.25,-1.37) and less added sugar (?5.66 g; 95% CI: ?9.63,-1.65) at the end of the trial. Daily fruit and vegetable intake decreased in both the intervention and control groups compared to baseline, albeit this decrease was 23.88 g (95% CI: 7.36, 40.40) lower in the intervention group. Waist circumference (?0.84 cm; 95% CI: ?1.68, 0.28) was lower in the intervention group at the end of the program; the effect was mainly observed at stage one. Dose and reach were also higher at stage one.

Conclusions

The trial had positive effects on risk factors for non-communicable diseases, i.e. decreased consumption of unhealthy snacks. The program strategies must be implemented at the national level through collaboration between the academia and policy makers to assure impact at larger scale.

Trial registration

ClinicalTrial.gov-NCT01004367.

     

Role of resistance physical exercise in preventing testicular damage caused by chronic ethanol consumption in UChB rats

Ethanol consumption is associated with spermatogenesis damage and testosterone level alterations. Alcohol remains the most commonly used substance among athletes and sports enthusiasts. This study evaluated whether resistance physical exercise can reduce the testicular damage caused by ethanol exposure. A total of 36 ethanol drinking (UChB) rats were divided into four groups: C (control rats), ETOH (ethanol consumption), ETOH + T (ethanol consumption + physical training), and T (group physical training). The physical training component of the T and ETOH + T groups was based on a resistance training model consisting of four sets of 10 jumps, with an increasing overload of 50–70% of the body weight attached to the chest three times per week. Rats in the ETOH and ETOH +T groups received 10% ethanol. At postnatal day 90, the rats were sacrificed. Blood sample was collected for hormonal analysis, and the testicles were weighed and processed for histopathological, morphometric, and immunohistochemical analyses. The ETOH group showed an increase in testosterone levels. The immunohistochemical of androgen receptor and the absolute weight of the testes were higher in the ETOH and ETOH + T groups, while the ETOH animals showed a decreased weight gain index. The number of abnormal seminiferous tubules increased in the ETOH and T groups compared to those in the control group (C); however, the association with treatment (ETOH + T group) prevented this effect and decreased caspase‐3 production. In conclusion, these findings show that the combination of ethanol consumption and resistance physical exercise can prevent testicular damage in adult UChB rats.     

TiF4 gel effects on tubular occlusion of eroded/abraded human dentin

This in situ study evaluated the tubular occlusion caused by 4% TiF₄ gel on the surface of eroded/abraded dentin. Sixty human dentin samples were eroded in vitro and assigned into six groups (n = 10) according to the in situ surface treatment and number of cycling days: 4% TiF₄ gel applied once (TiF₄1), twice (TiF₄2), or three times (TiF₄3) followed by 2, 4, and 6 days of erosive/abrasive in situ cycling, respectively. Control groups (no treatment) were subjected to 2 (C1), 4 (C2), and 6 (C3) days of erosive/abrasive in situ cycling only. A seventh group (n = 10) was comprised by in vitro uneroded samples (UN), subjected to 6 days of in situ erosive/abrasive cycling. Each cycling day consisted on six erosive (0.5% citric acid, pH 2.6) and one abrasive events. Environmental scanning electron microscopy micrographs were taken. For all groups, blinded examiners assessed dentin tubules occlusion using visual scores (0—unoccluded, 1—partially occluded by granular deposits, 2—partially occluded by reduction in tubular lumen into diamond shape, 3—completely occluded) on images captured prior and after the in situ phase. Scheirer‐Ray‐Hare test demonstrated that treatments significantly affected tubule occlusion (p < .001). Dunn's test showed that tubule occlusion in TiF₄3 was significantly higher than in C1. Tubule occlusion in remaining groups did not differ from that observed in groups TiF₄3 and C1. Tubule occlusion was significantly higher after in situ phase. It may be suggested that TiF₄, when applied three times, was able to positively change tubule occlusion of dentin samples.