E-learning in secondary–tertiary transition in mathematics: for what purpose?

Mathematics is a challenging subject for many science freshmen, and failing mathematics exams is a major factor in university dropout rates. Many factors, including metacognitive, affective and linguistic ones, play a role in students’ difficulties in mathematics. Starting from this perspective, we conducted a theoretical exploration of the potential of online environments in helping students counteract the mathematical difficulties they face in the transition from secondary school to university. Although this secondary–tertiary transition and the use of technology are both widely researched issues in mathematics education, the potential of technology in helping students in the “rite of passage” to tertiary education has not yet been researched. This paper reports on the developed theoretical framework and on the preliminary findings from the implementation of an e-learning course that we designed with the aim of supporting students in the critical phase of transition from secondary school to university

Class switch recombination in selective IgA-deficient subjects

Selective IgA deficiency is a common immunodeficiency in Caucasians, but the molecular basis of the disorder remains elusive. To address this issue we examined the molecular events leading to IgA production. Naive IgD positive B cells were purified from four donors with IgA deficiency and four control donors, all Caucasians. Stimulation of B cells from IgA-deficient donors with the cytokines transforming growth factor (TGF)-β, interferon (IFN)-γ or interleukin (IL)-10 in the presence of anti-CD40 antibodies showed reduced expression of both activation-induced cytidine deaminase (AID) and α germline transcripts (GLT) compared to controls. It was possible, however, to induce AID and α GLT when stimulating the cells with anti-CD40 antibody and TGF-β in the combination with IL-10. Moreover, in anti-CD40 antibody-stimulated cultures, addition of IL-10 or IL-10 + TGF-β in combination, induced IgA production, albeit lower than found in B cells from controls. The B cells from the IgA-deficient subjects were less effective in differentiating into CD138+ X-box binding protein 1 (XBP-1)+ plasma cells when stimulated with TGF-β, IFN-γ or IL-10. Interestingly, when adding IL-4 to TGF-β alone or in combination with IL-10, the immunoglobulin production in B cells from IgA-deficient donors was comparable with those of normal controls. These data show that in healthy subjects in vitro IgA production can be up-regulated by addition of IL-10 to CD40-stimulated B cells, whereas a similar B cell differentiation does not occur in IgA-deficient subjects. Addition of IL-4, however, reverts this abnormality

Reproductive and Immune System Interactions in the Context of Life History and Sexual Selection Theory

Host variation in parasite load abounds, both within and across natural populations. The forces that shape and maintain this variation, however, are much less obvious. Over the past two decades, the emerging field of ecoimmunology has begun to address the underlying sources of this variation and its evolutionary consequences. Clearly, spatial and temporal heterogeneity in the environment contribute to variation in host parasite load by varying parasite distribution and abundance. However, host variation in the ability to acquire resources, and differences in how these resources are allocated, also play an integral role in parasite susceptibility. That is to say, not all individuals within a population are capable of managing the cost of immune defense, or may employ different cost-managing strategies. This realization has spurred a surge in studies focused on how immune pathways compete with other costly physiological pathways, such as those associated with reproduction. Interest in this relationship has no doubt been driven by the reproductive system\u27s high energetic cost and its direct association with host fitness. In this chapter, I examine the interactions between reproduction and immunity to highlight the simultaneous role both play in the evolution of immunological and reproductive adaptations. I begin by placing this interaction in the context of life history theory and discuss how competition for limited resources may constrain the evolution and expression of both systems. I then discuss the role that parasites play in directly shaping reproductive adaptations through sexual selection. In this discussion, I attempt to shed light on the lingering controversy that has overshadowed genetic benefit models and provide concrete predictions for future directions