Combined per‐capita and abundance effects of an invasive species on native invertebrate diversity and a key ecosystem process

1. Invasive alien species (IAS) are leading to the homogenisation of taxonomic and functional biodiversity, with negative consequences for key ecosystem processes in fresh water. Invasive signal crayfish (Pacifastacus leniusculus) is expected to disrupt detritus-based food webs by affecting leaf breakdown and/or by decreasing invertebrate density and diversity through predation. The combination of per-capita and abundance effects of P. leniusculus in invaded ecosystems is still largely unknown. 2. A four-week field experiment was established in Rabaçal and Tuela Rivers (NE Portugal) to assess effects of P. leniusculus on invertebrate taxonomic and functional diversity and leaf litter breakdown following a gradient of invasion. We controlled the presence and absence of crayfish by placing the animals and leaf litter inside cages at six sites (three sites per river) according to the crayfish in situ abundance (absent, low, high). Cages were covered with coarse-or fine-mesh net to allow or prevent invertebrates from accessing the leaves. 3. Results showed that higher crayfish in situ abundance led to a decrease in abundance, richness and Shannon diversity of invertebrates and to changes in the communities’ structures. Higher crayfish abundance led also to a decrease in invertebrate functional redundancy and an increase in the percentage of invertebrate taxa with resistance forms. Leaf litter breakdown increased with crayfish presence and decreased at sites with higher crayfish abundance. 4. Overall, signal crayfish changed the community structure of invertebrates, with potential severe long-term effects on native communities and leaf litter breakdown. Given the widespread distribution of signal crayfish (and other crayfish species), their ecological impacts should be assessed carefully, especially in pristine freshwater ecosystems such as those described here.This work was supported by the strategic programme UIDB/04050/2020 funded by the Portuguese Foundation for Science and Technology (FCT). FCT supported this work through the scholarship SFRH/BD/119957/2016 (F. Carvalho).info:eu-repo/semantics/publishedVersio

Polyhydroxyfullerene binds cadmium ions and alleviates metal-induced oxidative stress in saccharomyces cerevisiae

The water-soluble polyhydroxyfullerene (PHF) is a functionalized carbon nanomaterial with several industrial and commercial applications. There have been controversial reports on the toxicity and/or antioxidant properties of fullerenes and their derivatives. Conversely, metals have been recognized as toxic mainly due to their ability to induce oxidative stress in living organisms. We investigated the interactive effects of PHF and cadmium ions (Cd) on the model yeast Saccharomyces cerevisiae by exposing cells to Cd (<= 5 mg liter(-1)) in the absence or presence of PHF (<= 500 mg liter(-1)) at different pHs (5.8 to 6.8). In the absence of Cd, PHF stimulated yeast growth up to 10.4%. Cd inhibited growth up to 79.7%, induced intracellular accumulation of reactive oxygen species (ROS), and promoted plasma membrane disruption in a dose- and pH-dependent manner. The negative effects of Cd on growth were attenuated by the presence of PHF, and maximum growth recovery (53.8%) was obtained at the highest PHF concentration and pH. The coexposure to Cd and PHF decreased ROS accumulation up to 36.7% and membrane disruption up to 30.7% in a dose- and pH-dependent manner. Two mechanisms helped to explain the role of PHF in alleviating Cd toxicity to yeasts: PHF decreased Cd-induced oxidative stress and bound significant amounts of Cd in the extracellular medium, reducing its bioavailability to the cells.FEDER-POFC-COMPETE; Portuguese Foundation for Science and Technology [PEst-OE/BIA/UI4050/2014, PTDC/AAC-AMB/121650/2010]; [SFRH/BD/45614/2008]; [Pest-OE/EQB/LA0023/2013

Microbial decomposers communities are mainly structured by trophic status in circumneutral and alkaline streams

In streams, the release of nitrogen and phosphorus is reported to affect microbial communities and the ecological processes they govern. Moreover, the type of inorganic nitrogen (NO3, NO2 or NH4) may differently impact microbial communities. We aimed to identify the environmental factors that structure aquatic microbial communities and drive leaf-litter decomposition along a gradient of eutrophication. We selected 5 circumneutral (Portuguese) and 5 alkaline (French) streams differing in nutrient concentrations to monitor mass loss of alder leaves, bacterial and fungal diversity by PCR-DGGE, fungal biomass and reproduction, and bacterial biomass during 11 weeks of leaf immersion. The concentrations of inorganic nutrients in the stream water ranged from 5 - 300 µg L-1 SRP; 0.30 – 5.50 mg L-1 NO3-N; 2 - 103 µg L-1 NO2-N; and < 4 - 7,100 µg L-1 NH4-N. Species richness was maximum in moderately anthropized (eutrophic) streams but decreased in the most anthropized (hypertrophic) streams. Different species assemblages were found in subsets of streams of different trophic status. In both geographic areas, the limiting nutrient, either nitrate or phosphate, stimulated the microbial activity in streams of intermediate trophic status. In the hypertrophic streams, fungal biomass and reproduction were significantly lower and bacterial biomass dramatically decreased at the site with the highest ammonium concentration. The limiting nutrients that defined the trophic status were the main factor structuring fungal and bacterial communities whatever the geographic area. Very high ammonium concentration in the stream water most probably has negative impacts on microbial decomposer communities

Association between self-control and health risk behaviors: a cross-sectional study with 9th grade adolescents in São Paulo.

BACKGROUND: Self-control (SC) has been consistently found associated with diverse health risk behaviors (HRBs), but little research refers to low- and middle-income countries. Furthermore, there is evidence that some HRBs tend to aggregate, however studies with the specific purpose of addressing the relation between SC and multiple health risk behaviors (MHRBs) are rare. The objective of this study is to analyze these associations and provide evidence to help filling these gaps. METHODS: A sample of 2106 9th grade students from the city of São Paulo responded a self-administered questionnaire in 2017. We tested the association of SC measured as an ordinal variable with four levels (higher, high, medium and low) with six HRBs (binge drinking, marijuana use, smoking, high consumption of ultra-processed food, sedentary behavior and bullying perpetration), in both separated and aggregated forms (MHRBs), controlling for potential confounders. Binary logistic regression was used to test the association between exposure (SC) and single outcomes. In order to analyze the association of SC with MHRBs, multinomial logistic regression was employed. RESULTS: SC was associated with five of six HRBs investigated and with MHRBs. The effect size of the association of SC and MHRBs increased in a steep pattern with accumulation of more HRBs. CONCLUSION: Low self-control is associated with most HRBs investigated and the magnitude of the association increases when more than two or three HRBs are accumulated. There seems to be a group of adolescents in a position of pronounced vulnerability for MHRBs. This should be considered when designing public policy and prevention programs. In contexts of limited or scarce resources and public funds, interventions focusing the most vulnerable groups, instead of universal interventions, should be considered

Theme choice in a Project-Based Learning

This article discusses interdisciplinarity in the teaching of Statistics through a Project-Based Learning. We´re sharing the discussion aroused by the publishing of the Common National Curriculum Base in 2018, that suggests learning projects, whose level of complexity and broadness increases gradually throughout the entire basic education (from six to seventeen years old). Our goal is to highlight the initial moment, which is paramount to the success of this approach:  the selection of the theme to be investigated. Initially, it is a qualitative research study that analyses official documents, recent studies in the area, as well as recordings of the sessions in which teachers and students discuss the theme to be chosen. In the end, a few considerations that may contribute to promoting Statistics Literacy are presented

El desarrollo de la alfabetización estadística de los estudiantes de secundaria brasileña:

Brasil atraviesa una crisis institucional, agravada por los efectos de la pandemia de COVID-19. El gobierno federal apoya sus posiciones antidemocráticas difundiendo noticias falsas. Un ejemplo reciente fue el discurso del presidente brasileño en la 76ª sesión de la Asamblea General de las Naciones Unidas. Presentamos una investigación cualitativa enfocada en una experiencia de enseñanza basada en proyectos, en vista de la Estadística Cívica. Analizamos la confrontación de los datos presentados en este discurso con información recolectada de otras fuentes, con el uso de textos ricos y en la lectura e interpretación de dados dinámicos, elementos de gran relevancia para la promoción de la alfabetización estadística. Nuestro objetivo es destacar las posibles contribuciones de la Estadística para comprender y combatir la difusión de noticias falsas

El desarrollo de la alfabetización estadística de los estudiantes de secundaria brasileña: : un enfoque a través de las Estadísticas Cívicas

Brasil atraviesa una crisis institucional, agravada por los efectos de la pandemia de COVID-19. El gobierno federal apoya sus posiciones antidemocráticas difundiendo noticias falsas. Un ejemplo reciente fue el discurso del presidente brasileño en la 76ª sesión de la Asamblea General de las Naciones Unidas. Presentamos una investigación cualitativa enfocada en una experiencia de enseñanza basada en proyectos, en vista de la Estadística Cívica. Analizamos la confrontación de los datos presentados en este discurso con información recolectada de otras fuentes, con el uso de textos ricos y en la lectura e interpretación de dados dinámicos, elementos de gran relevancia para la promoción de la alfabetización estadística. Nuestro objetivo es destacar las posibles contribuciones de la Estadística para comprender y combatir la difusión de noticias falsas

El desarrollo de la alfabetización estadística de los estudiantes de secundaria brasileña: : un enfoque a través de las Estadísticas Cívicas

Brasil atraviesa una crisis institucional, agravada por los efectos de la pandemia de COVID-19. El gobierno federal apoya sus posiciones antidemocráticas difundiendo noticias falsas. Un ejemplo reciente fue el discurso del presidente brasileño en la 76ª sesión de la Asamblea General de las Naciones Unidas. Presentamos una investigación cualitativa enfocada en una experiencia de enseñanza basada en proyectos, en vista de la Estadística Cívica. Analizamos la confrontación de los datos presentados en este discurso con información recolectada de otras fuentes, con el uso de textos ricos y en la lectura e interpretación de dados dinámicos, elementos de gran relevancia para la promoción de la alfabetización estadística. Nuestro objetivo es destacar las posibles contribuciones de la Estadística para comprender y combatir la difusión de noticias falsas

Effects of command and guided discovery teaching styles on acquisition and retention of the handstand

The influential Mosston’s Spectrum of Teaching Styles is a guide to teaching decisions in Physical&nbsp;Education. This highly researched topic has been tested in many contexts so that our focus is centered&nbsp;on the type of skill during motor skill acquisition in physical education settings. Given that the tasks&nbsp;employed in the studies have been either specialized or manipulative fundamental skills, we sought to&nbsp;extend our understanding of the issue addressing the effects of teaching styles in the process of learning&nbsp;a stability fundamental skill. Our purpose was to examine motor and psychological effects of command&nbsp;and guided discovery teaching styles from Mosston's Spectrum in the acquisition and retention of the&nbsp;handstand in scholars. Third graders from a suburban school in Sao Paulo, Brazil, were assigned to a&nbsp;command (n=22) and a guided discovery (n=23) group. The process of learning the handstand lasted&nbsp;six acquisition sessions, carried out between a pretest and a posttest/retention. We used as dependent&nbsp;variables the motor developmental level (initial, elementary and mature), the movement ratings (scores&nbsp;from 0 to 10) and the motivation levels (post-learning self-reported subscales from the Intrinsic Motivation&nbsp;Inventory). The guided discovery teaching style led more scholars to reach the mature developmental&nbsp;stage of the handstand on retention compared to the command teaching style. No group differences&nbsp;were detected with respect to ratings or intrinsic motivation. Regardless of the group, the pretest ratings&nbsp;were lower than the posttest ones as well as boys scored higher in pressure and tension subscale as&nbsp;compared to girls. The current findings suggest that both teaching styles promoted motor acquisition,&nbsp;but the guided discovery teaching style seemed to yield superior handstand retention