EXPLORING PROSPECTIVE ELEMENTARY MATHEMATICS TEACHERS’ KNOWLEDGE: A FOCUS ON FUNCTIONAL THINKING

The importance of students being acquainted with algebraic ideas before secondary education has been revealed in the research literature. It is therefore essential that prospective elementary teachers (PTs) be prepared to instill an early algebra perspective in their teaching. However, PTs often show difficulties in algebra content knowledge, which need to be diagnosed aiming to assist them in developing the required knowledge to teach according to that perspective. This study aims to understand what aspects of functional thinking Spanish and Portuguese elementary PTs exhibit at the beginning of their teacher education program. The findings show that although PTs from both countries use different strategies to generalize functional relationships, the occurrence of successful strategies is low. Also, most participants provide local approaches in their interpretation of relationships between variables and reveal difficulties in understanding and connecting different representations of functions. These difficulties show that PTs lack important knowledge about functional thinking. By providing a framework concerning the functional thinking required for PTs to teach within an early algebra perspective, we shed light on a necessary step for teacher education programs to diagnose PTs’ functional thinking and to assist them in developing the needed mathematical knowledge to teach accordingly

Polymorphisms in cytochrome P450 versus cline distribution of evolutionary lineages in Apis mellifera iberiensis

Honey bees (Apis mellifera) are the most prominent and economically important pollinator species worldwide. However, the reported decline of its populations in several regions of the world over the last decades is of concern. The causes are manifold, including the spread of pathogens and parasites, malnutrition and habitat loss, climate change and xenobiotics, especially pesticides. Among the main mechanisms used by insects to cope with the adverse effects of xenobiotics is the metabolic resistance mediated mainly by three superfamilies of enzymes: the cytochrome P450 monooxygenases, the glutathione transferases and the carboxylesterases. We hypothesize that the genetic background influences the sensitivity to pesticides or detoxification capacity of different honey bee populations, ecotypes and subspecies. The Iberian Peninsula provides an interesting scenario to study the genetic variability of the cytochrome P450 genes given the co-occurrence of two clinally distributed evolutionary lineages, as a result of secondary contact. In this study, the genetic variability of six genes of the cytochrome P450 superfamily (CYP6AS3, CYP6AS4, CYP6AS5, CYP6AS7, CYP6AS12 and CYP6AS17) was analyzed in the Iberian honey bee (Apis mellifera iberiensis) to provide more information on the mechanisms of resistance to xenobiotics and to identify the genetic variation involved in local adaptation. Genomic signal of selective sweeps was detected in three genes, of which CYP6AS5 presents the highest number of point mutations under selection, being proposed as a candidate gene to perform gene expression studies. We discuss the correlation between the variability of P450 genes and the distribution of the evolutionary lineages in the Iberian Peninsula. The identification of polymorphisms in these genes promises to shed light on the relationship between diversity and xenobiotic tolerance of A. m. iberiensis.info:eu-repo/semantics/publishedVersio

Toward Collaborative Cross-Sector Business Models for Sustainability

Sustainability challenges typically occur across sectoral boundaries, calling the state, market, andcivil society to action. While consensus exists on the merits of cross-sector collaboration, ourunderstanding of whether and how it can create value for various, collaborating stakeholders is still limited. This Special Issue focuses on how new combined knowledge on cross-sector collaboration and business models for sustainability can inform the academic and practitioner debates about sustainability challenges and solutions. We discuss how cross-sector collaboration can play an important role for the transition to new and potentially sustainability-driving business models given that value creation, delivery and capture of organizations are intimately related to the collaborative ties with their stakeholders. Sustainable alternatives to conventional business models tend to adopt a more holistic perspective of business by broadening the spectrum of solutions and stakeholders and, when aligned with cross-sector collaboration, can contribute new ways of addressing the wicked sustainability problems humanity faces

Molecular diversity and selective sweeps in Iberian honey bee

Deciphering the genetic basis of the process of adaptation of organisms has been and remains one of the fundamental goals of evolutionary biology. Genomes contain information related to the history of natural populations. The Iberian honey bee (Apis mellifera iberiensis Engel 1999) exhibits a complex genetic diversity pattern of clinal variation shaped not only by evolutionarily neutral processes but also by selection. Unravelling the variation of subgenomic regions in this subspecies not only allows us to better understand the complexity of clinal patterning, but also the identification of genetic variation involved in local adaptation. Several regions related to vision, xenobiotic detoxification, and immune response have shown signals of selection in A. m. iberiensis. In this study, analyses of sequence variation around candidate subgenomic regions (~100 kpb) have been carried out. The aims of this work are to provide further evidence of positive selection in the Iberian honey bee, to localize at a much finer scale the direct points of such selection, and to find the underlying source of the beneficial alleles or variants.info:eu-repo/semantics/publishedVersio

Candida albicans antimicrobial and antibiofilm activity of novel endodontic solvents

Background: Candida albicans is the most prevalent fungi isolated in endodontic infections. In this study, the ability of C. albicans biofilm to tolerate the novel solvent mixtures methyl ethyl ketone (MEK)/tetrachloroethylene (TCE) and MEK/orange oil (OOil) sequentially to the standard irrigation of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic (EDTA) was evaluated. Methods: Biofilm cell cultures of C. albicans SC 5314 were treated sequentially with NaOCl and EDTA and exposed to MEK/TCE or MEK/OOil. The effect of the antimicrobial treatment was evaluated using the disk diffusion method for planktonic culture, and the enumeration of colony-forming units (CFUs) and scanning electron microscope (SEM) for biofilm cell culture. Results: C. albicans mature biofilm (24 h) was significantly reduced in biomass and cell viability after solvent mixtures exposure, compared with the previous NaOCl and EDTA treatments. MEK/OOil combination caused a total reduction of biofilm, while with MEK/TCE, there was a 3-log (CFU/cm2) reduction compared with the sequence NaOCl and EDTA, and a 4-log (CFU/cm2) reduction compared with the control. Conclusions: The additional exposure of a preformed 24 h C. albicans biofilm to novel solvent mixtures MEK/TCE and MEK/OOil caused a positive antibiofilm impact, overcoming the performance of the conventional endodontic irrigating protocol.This article was supported by National Funds through FCT-Fundação para a Ciência e a Tecnologia, I.P., within CINTESIS, R&D Unit (reference UIDB/4255/2020). This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and grant ref 2020.05720.BD for Liliana Fernandes; BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Reduced SNP panels for genetic identification and introgression analysis in the dark honey bee (Apis mellifera mellifera)

Beekeeping activities, especially queen trading, have shaped the distribution of honey bee (Apis mellifera) subspecies in Europe, and have resulted in extensive introductions of two eastern European C-lineage subspecies (A. m. ligustica and A. m. carnica) into the native range of the M-lineage A. m. mellifera subspecies in Western Europe. As a consequence, replacement and gene flow between native and commercial populations have occurred at varying levels across western European populations. Genetic identification and introgression analysis using molecular markers is an important tool for management and conservation of honey bee subspecies. Previous studies have monitored introgression by using microsatellite, PCR-RFLP markers and most recently, high density assays using single nucleotide polymorphism (SNP) markers. While the latter are almost prohibitively expensive, the information gained to date can be exploited to create a reduced panel containing the most ancestry-informative markers (AIMs) for those purposes with very little loss of information. The objective of this study was to design reduced panels of AIMs to verify the origin of A. m. mellifera individuals and to provide accurate estimates of the level of C-lineage introgression into their genome. The discriminant power of the SNPs using a variety of metrics and approaches including the Weir & Cockerham's FST, an FST-based outlier test, Delta, informativeness (In), and PCA was evaluated. This study shows that reduced AIMs panels assign individuals to the correct origin and calculates the admixture level with a high degree of accuracy. These panels provide an essential tool in Europe for genetic stock identification and estimation of admixture levels which can assist management strategies and monitor honey bee conservation programs

Putting the “love of humanity” back in corporate philanthropy : the case of health grants by corporate foundations

With the growing call for private sector actors to address global challenges, it is necessary to first assess whether regions with the greatest needs are accessing corporate philanthropy. In this paper, we ask whether corporate philanthropy is reaching those with the greatest health-care needs. Drawing on economic geography and corporate homophily, we argue that corporate philanthropy tends to exacerbate health inequality as grants are destined for counties with fewer health problems. We test and find support for this hypothesis using data on health grants made by US corporate foundations and county-level health data. Our results that corporate health grants are less likely to go to counties which have a lower proportion of medical service providers and insured citizens suggest that corporate foundations are unwittingly complicit in worsening the resource gap between small, poor, rural counties and large, wealthy, urban counties. From an ethical perspective, we provide some guidance as to how this may be corrected

O papel dos ostensivos na representação de variáveis estatísticas qualitativas

A essência da Estatística está na possibilidade de extração de informações relevantes a partir de dados coletados sobre aspectos da realidade. Para isso, os dados são transformados em tabelas, gráficos e medidas resumo. A compreensão dessas transformações pelo estudante é crucial para a aprendizagem. Neste artigo tecem-se reflexões teóricas sobre as ações de estudantes e o papel do material concreto manipulável como ostensivos na gestão e na representação de variáveis estatísticas qualitativas que sofrem transformações em diferentes registros semióticos. Para isso, utilizaram-se a teoria dos registros de representação semiótica e a Teoria Antropológica do Didático, essa última limitada à sua perspectiva de objetos ostensivos e não ostensivos. As reflexões indicam que a utilização dos ostensivos é motivadora no âmbito de ensino e aprendizagem. Assim, espera-se que as reflexões tecidas aqui contribuam para melhor compreensão e ensino de conceitos estatísticos, bem como para realização de novas pesquisas