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Mathematical culture is an essential part of general culture, and mathematical proof is the essence of mathematical culture, which plays an essential role in education for sustainable development. The presented research focuses on the following issue: Can the use of visual tools contribute to a better understanding of mathematical proofs presented within the framework of courses in graph theory? The research focuses on Czech university students of computer science. The presented results were achieved in a pedagogical experiment based on a pre-test, treatment and post-test design carried out during three academic years before the COVID pandemic period. In the pre-test and post-test phases, students were tested to determine their level of mathematical logic knowledge. Visual applications were used in teaching in the treatment phase. The research results clearly showed that the use of visual tools supporting formal explanation of mathematical proofs results in better understanding of the abstraction of the presented process and thus contributes significantly to sustainability in mathematical education. Thanks to the use of the mentioned visual tools during the COVID pandemic period, when schools had to switch to on-line education, the students’ results were comparable to those from face-to-face classes.

Based on the balneotherapeutic applications of mineral spring water and particularly sulphurous water, the aim of our research was to study the physicochemical and microbiological parameters of some drainage waters of Siriu dam that showed a strong hydrogen sulphide odour. In addition, due to the corrosive effect of some groups of microorganisms, such as iron-oxidizing bacteria and sulphatereducing bacteria, the present paper also aimed to detect their presence in order to signal the need for some disinfection measures. According to physicochemical analysis, there has been found an external drain that is suitable for use in balneotherapy, presenting a balanced content of mineral elements such as sulphur, calcium, silicon, chlorine and potassium. However, due to the presence of potentially toxic phytoplankton microorganisms such as Microcystis sp. and Phormidium sp. it is necessary to disinfect this water source before using it for any purpose. On the other hand, the identification of both sulphate-reducing bacteria and iron-oxidizing bacteria in the drainage waters of Siriu dam should be considered as an alarm signal as they may lead to bio-corrosion and deterioration of metallic or concrete structures, affecting the integrity of the dam and hydropower constructions.

Dans le contexte où deux approches s’opposent dans les recherches et les pratiques à l’éducation préscolaire, il est pertinent de savoir si les pratiques enseignantes sont cohérentes avec les programmes ministériels prescrivant l’approche développementale ou privilégient plutôt l’approche scolarisante. Cet article présente les résultats d’une recherche exploratoire, quantitative, visant à documenter les choix pédagogiques dans l’éducation préscolaire au Québec. Un questionnaire a été administré auprès de 159 enseignantes. Il s’avère que la préférence des enseignantes pour l’apprentissage de la langue écrite penche légèrement pour des pratiques scolarisantes. La valeur qu’elles accordent au jeu augmente leur préférence pour les pratiques développementales. Les enseignantes en milieu socioéconomique défavorisé expriment une préférence plus marquée pour des pratiques développementales que celles en milieu favorisé., In the context of opposing approaches to research and educational practices, it is important to know whether teaching practices are consistent with ministerial programs that prescribe a developmental or an educational approach. This article presents quantitative, exploratory research that aims to document pedagogical choices in preschool education in Québec. A questionnaire was given to 159 teachers. Results showed slight preferences on the part of teachers for academic approaches to language learning. The value teachers placed on play increased their preference for developmental approaches to learning. Teachers in socioeconomically disadvantaged areas expressed a more distinct preference for developmental approaches than those in comparatively more socioeconomically advantaged areas.

Danube Delta shallow lakes experience cyanobacteria blooms that can negatively affect the aquatic ecosystem. Although there are several studies on Danube Delta cyanobacteria, little is known about their spatial–temporal patterns and the potential predictive role they can offer. We therefore analyzed the distribution of cyanobacteria in 19 lakes belonging to three lake complexes and tested whether their seasonal dynamics are in line with the predictions of the PEG model. Furthermore, we investigated to which extent cyanobacteria diversity and abundance were related to lake hydrogeomorphological characteristics such as surface, water level, connectivity, water retention, flood risk, and transparency. Although lakes had different seasonal cyanobacterial assemblages, the biovolume and genus richness had a geographical pattern, decreasing from south-east (lakes forming the fluvial delta) towards north-west (lakes forming the maritime delta). Cyanobacteria biovolume reflected largely the PEG model peaking in summer (the fluvial delta) and autumn (the maritime delta). Genus richness followed the same pattern. Cyanobacteria distribution was predicted by various abiotic (e.g., risk of flooding, connectivity) and biotic factors (e.g., submersed macrophytes, phytoplankton diversity, peat deposits). Our study contributes to the understanding of cyanobacteria diversity and distribution in shallow interconnected lakes by revealing the complexity of predictors for geographical and seasonal patterns.

Urban areas face numerous provocations, such as air, water, and soil contamination. Additionally, urban lakes have numerous beneficial services that contribute to urban sustainability. In urban aquatic ecosystems, X-ray fluorescence can provide complex answers regarding the presence of elements associated with environmental risk. The study aimed to screen the elements with different potentials (critical raw materials—CRMs; toxic; potentially toxic) from Phragmites australis leaves along the Colentina urban river. The samples from the peri-urban and urban river courses highlighted the presence of elements with different potentials for ecosystems and human health. The investigated stations were influenced by regional anthropogenic pressures, where P. australis highlighted the absorption of the dominant elements found in the environment. From the total of 56 elements present in the samples, some have structural roles (K, Si, Ca, and Cl), some are from the CRM category, and some are airborne heavy metals and rare metals. Furthermore, among CRMs, cesium, lanthanum, magnesium, phosphorus, vanadium, sulfur, holmium, and titanium were recorded with higher values. Although the values of the elements in the anthropogenic source were in low concentrations, spatial differences were highlighted. The stations in agricultural areas were different from the peri-urban and urban ones.

Despite the growing list of elements assessed and recognised as environmental and human health hazards, pollution monitoring and mitigation strategies are mandatory only for a limited number of metals, for which ambient air quality limits are defined by national and international policies. In order to overcome this deficiency, and promote cost-effective strategies and methods to assess airborne pollution, biomonitoring has been employed on several occasions using various protocols and organisms. Here we present a complex national monitoring study based on a combined approach that integrates air pollution data obtained through passive biomonitoring using the foliar content of various tree species and active biomonitoring with Hylocomium splendens moss bags. Concentrations of seven air pollutant metals, Al, Cr, Co, Cu, Fe, Mn and Zn, not regularly monitored and lacking established legal limit values, were measured in 410 passive and 142 active biomonitoring sampling sites across Romania, in two seasons, representing the largest study reported up-to-date applying complementary passive and active biomonitoring. Literature data reporting concentrations from uncontaminated areas was used to establish the concentration limits for four pollution levels (no, low, medium and high pollution), in order to develop a colour-coded warning system. High pollution levels were measured for 4.7% of passive and 9.8% of active monitoring samples. The largest proportions of samples showing high pollution levels were obtained for zinc (38.4%, for active monitoring) and chromium (18.9%, for passive monitoring). A significantly higher element content was found in moss bag samples than in leaves/needles. Though we emphasize the potential of both passive and active biomonitoring in assessing airborne pollution, our experiences and findings show that the more standardized methodology of moss-bag biomonitoring is sounder and better suited for such large-scale studies than a study conducted on multiple tree species. Some of the difficulties encountered during the two biomonitoring studies are also reported, including the range limit of species and the lack of established reference values for pollution limits.

Eutrophication of shallow lakes often triggers a series of cascading ecological effects. Among these are shifts in the zooplankton community structure due to phytoplankton changes, or shifts in the fish community reducing size-selective feeding of planktivorous fish. In such conditions, larger zooplankton (e.g. Daphnia) can have a selective advantage. Re-oligotrophication can reverse such food-web interactions. Europe’s largest wetland system (the Danube Delta) went through a period of eutrophication and is now slowly recovering again. However, changes in the Daphnia populations triggered by eutrophication in this system have remained unstudied. We used different sampling strategies to screen 24 lakes (which differ in their ecological state) for the presence of Daphnia as well as for biotic and abiotic parameters potentially explaining Daphnia abundance. Daphnia densities were surprisingly low. We found D. magna ephippia in the sediment, but no D. magna in the water column. Microsatellite analyses on pelagic Daphnia populations confirmed the presence of the D. longispina complex and provided evidence for significant hybridisation events. FluoroProbe data showed that Daphnia was mainly present in lakes with a higher phytoplankton production. Our study provides insights into the spatial and temporal distribution of Daphnia in a very dynamic wetland system.

Biomonitoring, i.e. using plant species for measuring pollution levels, has been previously explored in several locations using various protocols and organisms in the search for effective strategies and practices for monitoring and reducing the levels of pollution. Here we present a tested and functional cost-effective method of using the foliar accumulation of tree species to develop a system for the long-term monitoring of airborne heavy metal bioaccumulation at a large, national scale. A total number of 1230 leaf samples have been collected during a vegetation season in 410 sampling locations scattered across Romania. Concentration levels were determined using an inductively coupled plasma mass spectrometer. Data from literature were used as reference values for the natural concentration of heavy metals in plants. Values exceeding these levels were considered as indicators of pollution, and used to define pollution thresholds. The maximum amounts measured in the collected samples were 152 mg kg−1 dry weight for lead, 25.65 mg kg−1 dry weight for cadmium, 65.51 mg kg−1 dry weight for nickel and 4.81 mg kg−1 dry weight for arsenic. For analysing and communicating the findings, the BioMonRo software has been developed as a novel tool for warning-informing and decision-making. The software, now implemented by the Ministry of Environment for monitoring environmental quality, uses concentration data to build up national heavy metal pollution maps and can generate reports, which are automatically sent to various stakeholders. Based on our findings, we consider that tree species are efficient biomonitors, and similar methods could be successfully used in extensive biomonitoring programmes (national, regional or European), and for informing authorities.

This study analyzed the metabolic potential of some functional groups of bacteria in aquatic urban systems and evaluated the abundance of communities of total heterotrophic bacteria in the water in relation to the monitored physico-chemical factors. The results obtained showed seasonal differences, especially in spring. The high values of the abundance of heterotrophs in winter are related to human activity at the sampling stations. Screening for four types of extracellular hydrolytic enzyme with potential for degradation of organic matter (amylases, lipases, proteases and cellulases) led to the conclusion that lipolytic bacteria were dominant in the studied ecosystems, while proteolytic bacteria were observed in low numbers, but were present in urbanized areas. The presence of cellulolytic bacteria is correlated with the development of macrophytic vegetation. The aim of the present study was oriented towards the evaluation of the anthropogenic input in several lakes surrounding Bucharest in the Nord-Eastern region. These urban ecosystems are generated as a requirement of city development. The microbiological and general enzymatic approaches generated some novel results concerning the pollution degree of aquatic urban ecosystems and could be considered as a platform for further investigation.

Understanding how microbial diversity influences ecosystem properties is of paramount importance. Cellular traits—which determine responses to the abiotic and biotic environment—may help us rigorously link them. However, our capacity to measure traits in natural communities has thus far been limited. Here we compared the predictive power of trait richness (trait space coverage), evenness (regularity in trait distribution) and divergence (prevalence of extreme phenotypes) derived from individual-based measurements with two species-level metrics (taxonomic richness and evenness) when modelling the productivity of natural phytoplankton communities. Using phytoplankton data obtained from 28 lakes sampled at different spatial and temporal scales, we found that the diversity in individual-level morphophysiological traits strongly improved our ability to predict community resource-use and biomass yield. Trait evenness—the regularity in distribution of individual cells/colonies within the trait space—was the strongest predictor, exhibiting a robust negative relationship across scales. Our study suggests that quantifying individual microbial phenotypes in trait space may help us understand how to link physiology to ecosystem-scale processes. Elucidating the mechanisms scaling individual-level trait variation to microbial community dynamics could there improve our ability to forecast changes in ecosystem properties across environmental gradients.

La différenciation pédagogique compte parmi les mesures censées améliorer la réussite scolaire de tous les élèves. Toutefois, le construit théorique reste flou et les enseignants y recourent rarement de façon systématique. Dans ce contexte, cet article vise à apporter des éclaircissements théoriques, en opérant tout d’abord la distinction entre différenciation pédagogique et pratique de différenciation. Une conceptualisation de la différenciation pédagogique appuyée sur le construit d’intentionnalité d’action est proposée. Des caractéristiques des pratiques de différenciation sont décrites afin de contribuer à leur opérationnalisation. Les résultats présentés proviennent d’une recherche qui s’est déroulée auprès de 24 enseignants du primaire au Québec, qui a compris une étape d’exploration de leurs représentations relatives à la différenciation pédagogique et une deuxième étape d’observation des pratiques effectives., Differentiated instruction is one of the measures intended to improve academic achievement for all students. However, its theoretical construct remains unclear and teachers rarely use it systematically. In this context, this article aims to provide theoretical clarification by first operating a distinction between differentiated instruction and the practice of differentiation. A conceptualization of differentiated instruction based on the construct of intentionality of action is then proposed. Features of practices of differentiation are also described in order to contribute to their operationalization. The results presented stem from a research conducted with 24 elementary teachers in Quebec, which included a first phase of exploration of their representations concerning differentiated instruction and a second phase of observation of actual practices.

This paper reports the invasive subspecies Podonevadne trigona ovum (Zernov, 1901), as dominant in the Danube-Black Sea Canal. In the first two years of the existence of the anthropogenic ecosystem (1985-1986) the zooplankton summarizes only 72 species. Over two decades it recorded the presence of 127 species. As a result of nutrient accumulation, in 2005, the zooplankton abundance has significantly increased, reaching 330 ind L-1, followed by an evident growth of biomass (2285 μg wet weight L-1). In 2005, the productivity registered 731.8 μg wet weight L-1/24h. Resume. Le present papier rapport l’existence de la sous-espece envahissante Podonevadne trigona ovum (Zernov, 1901), dominante dans le canal Danube – Mer Noire. La sous-espece appartient a l’ordre Onychopoda, et elle a une origine Caspienne. Dans les premieres deux annees qui suit l’apparition de cet ecosysteme anthropogenique (1985-1986), le zooplancton a ete represente par 72 especes; apres deux decennies, le nombre d’especes a augmente a 127. A la suite d’accumulation de nutriments, en 2005 l’abondance du zooplancton a augmentee de maniere significative, atteignant 330 ind L-1, suivie d’une augmentation marquee de la biomasse (2285 mg s.um. L-1). En 2005, la productivite du zooplancton a enregistre 731,8 mg mat.hum. L-1/24h.

Sfântu Gheorghe fluvial branch belongs to the macroregional hydrological system of the Danube Delta. In order to improve the navigation on the river branches, between 1983 and 1989 various technical works have been initiated, which later proved to be one of the most aggressive factors leading to changes over time in the Danube Delta. The influence of anthropogenic impact on the zooplankton biomass distribution patterns in Sfântu Gheorghe was investigated in 2008 - 2010 interval. From this perspective, the aim of this paper was to emphasize the structure and distribution of zooplankton in the new conditions of the river system. Seasonal sampling shows that Copepoda and Cladocera were the dominant groups while the protozoans (Ciliata and Testacea) presented the smallest values of biomass and also emphasized distinct differences among the three sampling periods: summer, spring and autumn.

The need to synthesize qualitative research in order to inform fields of study has been highlighted as a critical imperative in recent years. Since that time, there have been a number of attempts to identify methodological approaches to achieving such a goal. Despite some notable efforts in this regard, the metasynthesis research approach continues to be somewhat elusive with regard to its steps and procedures. The authors of this article describe their experience conducting a metasynthesis of qualitative research regarding transformation in chronic illness and disability. The particular emphasis of the article will be the practical strategies and procedures that assisted them in conducting the project in a rigorous and meaningful way. The authors emphasize the need for continued dialogue about strategies and procedures in metasynthesis that will aid researchers who are contemplating this complex research approach.

Dans un contexte de professionnalisation des enseignants, la compétence multiculturelle bénéficie d’un statut ambigu et controversé autant dans les discours gouvernementaux que dans la pratique enseignante. En s’appuyant sur des formalisations récentes du concept de compétence, cette étude vise à cerner le sens et le statut de la compétence multiculturelle de l’enseignant. Menée auprès de neuf étudiants-maîtres francophones, cette recherche exploratoire utilisant une méthodologie qualitative interprétative propose une définition de la compétence multiculturelle de l’enseignant et discute du statut à lui accorder parmi les autres compétences professionnelles. Enfin, des suggestions de développement de ladite compétence pendant la formation initiale des enseignants sont formulées. In the context of teacher professionalization multicultural competence receives an ambiguous and controversial status both in the government discourse and in teaching practice. Based on recent formalizations of the concept of competence, this study aims at defining the meaning and status of teachers’ multicultural competence. This exploratory research carried out with nine francophone student teachers used an interpretive qualitative methodology to propose a definition of multicultural competence for teachers, and discusses the status it should be granted among other professional competences. Suggestions are provided on how to devleop this competence during initial teacher education.

International audience; In this work, we present the linear and nonlinear optical properties of DNA as functional material, incorporated into a silica material matrix with rhodamine organic dye. We observed that even low concentration of DNA affects the aggregate behavior of the dyes in silica films. The samples with DNA showed higher transmittance and fluorescence efficiency. Moreover, the presence of DNA has been found to significantly enhance the nonlinear optical response of the systems. In this way, we prove that silica materials can provide suitable matrices for hybridization with functional molecules and can be utilized as active optical waveguide materials with enhanced nonlinear optical properties.

Dans un contexte où l’intégration des élèves à besoins particuliers en classe ordinaire exige une adaptation des pratiques pédagogiques et l’implantation d’approches inclusives, les pratiques différenciées semblent toujours présenter des défis aux enseignants. Afin de contribuer à proposer des pistes d’action documentées et efficaces, cette recherche a brossé dans un premier temps le profil des enseignants qui utilisent de façon systématique des pratiques différenciées. Les résultats ont été analysés du point de vue des relations avec des caractéristiques des milieux scolaires et avec des composantes du développement professionnel des enseignants., In a context where the integration of special needs students into regular classrooms requires an adaptation of pedagogical practices and the implementation of inclusive approaches, differentiated instruction always seem to present challenges for teachers. In order to contribute to the documented and effective courses of action, this research first drew the profile of teachers who systematically use differentiated instruction. The results were analyzed from the point of view of relationships with characteristics of school environments and with components of teacher professional development.

Ce texte explore les sens que de futurs enseignants attribuent à l’éducation multiculturelle, afin d’en déceler l’importance et les objectifs dans une perspective de vivre ensemble. Une recherche exploratoire utilisant des données qualitatives a été menée auprès de neuf étudiants-maîtres inscrits au programme de formation initiale à l’enseignement dans une université ontarienne. L’interprétation des résultats a conduit à la construction d’un modèle d’éducation multiculturelle qui essaie de la légitimiser dans le cadre d’une approche pédagogique différenciée., This text looks at how future teachers define multicultural education in order to discover its relevance and objectives in the context of living together. Nine masters students in an initial teacher training program at an Ontario university participated in an exploratory research study using qualitative data. The interpretation of the results led to the construction of a multicultural education model that attempts to legitimize the data within the framework of a differentiated pedagogical approach