There is widespread agreement that an adequate understanding of the nature of science (NOS) is a critical component of scientific literacy and a major goal in science education. However, we still do not know many specific details regarding how students and teachers learn particular aspects of NOS and what are the most important feature traits of instruction. In this context, the main objective of this review is to analyze articles from nine main science education journals that consider the teaching of NOS to K-12 students, pre-service, and in-service science teachers in search of patterns in teaching and learning NOS. After reviewing 52 studies in nine journals that included data regarding participants' views of NOS before and after an intervention, the main findings were as follows: (1) some aspects of NOS (empirical basis, observation and inference, and creativity) are easier to learn than others (tentativeness, theory and law, and social and cultural embeddedness), and subjective aspects of NOS and "the scientific method" seemed to be difficult for participants to understand; (2) the interventions most frequently lasted 5 to 8 weeks for students, one semester for pre-service teachers, and 1 year for experienced teachers; and (3) most of the interventions incorporated both decontextualized and contextualized activities. Given the substantial diversity in the methods and intervention designs used and the variables studied, it was not possible to infer a pattern of more-effective NOS teaching strategies from the reviewed studies. Future investigation should focus on (a) disentangling whether a difference exists between the easy and difficult aspects of learning NOS and formulating a theoretical explanation for distinguishing the two types of aspects and (b) assessing the effectiveness of different kinds of courses (e.g., history of science, NOS or informal) and strategies (e.g., hands-on vs. drama activities; SSI vs. HOS).

Using classic Golgi staining methods, we previously showed that the administration of synthetic glucocorticoid betamethasone in equivalent doses to those given in cases of human premature birth generates long-term alterations in Purkinje cell dendritic development in the cerebellar cortex. In the present study, we evaluated whether betamethasone alters the immunohistochemical expression of proteins that participate in cerebellar Purkinje cell dendritic development and maintenance, including microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor (BDNF) and the tyrosine kinase B receptor (TrkB), which are located predominantly in the cerebellar molecular layer where Purkinje cell dendritogenesis occurs. Consistent with our previous Golgi stain studies, we observed that animals prenatally exposed to a single course of betamethasone showed long-term alterations in the expression of MAP2, BDNF and TrkB. Additionally, these protracted molecular changes were accompanied by anxiety-like behaviors in the elevated plus maze and marble burying tests.

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Abstract.Previous animal studies have indicated that excessive prenatal circulating glucocorticoid (GC) levels induced by the antenatal administration of synthetic GC (sGC) significantly alter neuronal development in the cerebellar and hippocampal neurons of the offspring. However, it is unknown whether antenatal sGC administration results in long-term neocortical pyramidal cell impairment. In the current study, we examined whether an equivalent therapeutic dose of antenatal betamethasone phosphate (BET) in pregnant rats alters the Golgi-stained basilar dendritic length and histochemical expression of dendritic microtubule-associated protein 2 (MAP2) of neocortical pyramidal cells in infant, adolescent, and young adult offspring. The results obtained showed that in utero BET exposure resulted in a significant reduction in the basilar dendritic length per neuron and a transient reduction in histochemical MAP2 immunoreactivity. Consistent with previous hippocampal and cerebellar data, the present findings suggest that prenatal BET administration alters the dendritic growth of cerebrocortical pyramidal cells.

Our data show that long-lasting Purkinje cell dendritic impairments and anxiety-like behavior can be mitigated by postweaning EE.