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Abstraction is one of the most fundamental ideas in computer science (CS), and as such, according to Bruner [23], it should be taught spirally, starting as early as possible and revisited at every level of education. However, teaching CS abstraction to novices is a very challenging task, and CS educational research has often demonstrated students' difficulties in learning this idea, in different contexts and at different age levels. The challenge in teaching CS abstraction is even greater when dealing with young students, since according to theories on children's cognitive development, their abstraction abilities may still be not fully developed. In 2013, Armoni [5] introduced a framework for teaching abstraction in the context of algorithmic problem solving, intended for novice students. We studied the effect of this framework in an introductory CS course for 7 th graders, in which Scratch was used as the programming language for implementing algorithmic solutions. Our findings indicate that the framework was highly effective for developing CS abstraction skills as well as other related skills and aspects, such as the tendency to provide explanations for solutions, the use of initialization processes, and the perception of the nature of CS. It also significantly improved students’ general CS performance in this course.

Reduction is a powerful strategy for solving proof and design problems in multiple contexts of computer science (CS). It is characterized by establishing connections between problems that may seem very different and by using black boxes. Therefore, reduction is closely related to CS abstraction. In particular, understanding and employing reduction requires one to differentiate between a problem and its solution. The latter is at a lower level of abstraction; it describes how the problem is solved, as opposed to the higher level of abstraction, which describes what the solution should achieve. A series of studies investigated the use of reduction indicating its limited use as well as specific difficulties in using it, in different contexts and age levels. In particular, the students tended to open black boxes when they used reduction and confused a problem and its solution. Following these outcomes, CS researchers presented some general guidelines for teaching reduction. The main ones recommended an explicit spiral teaching of reduction while emphasizing its characteristics and principles, and in particular, distinguishing between problems and solutions. We implemented these recommendations in an undergraduate course on algorithms and studied the effectiveness of our pedagogical framework. The findings indicate a substantial improvement in the students’ use of reduction.

As a mediator of insulin-regulated gene expression, the FoxO1 transcription factor represents a master regulator of liver glucose metabolism. We previously reported that the high-mobility group AT-hook 1 (HMGA1) protein, a molecular switch for the insulin receptor gene, functions also as a downstream target of the insulin receptor signaling pathway, representing a critical nuclear mediator of insulin function. Here, we investigated whether a functional relationship existed between FoxO1 and HMGA1, which might help explain insulin-mediated gene transcription in the liver. To this end, as a model study, we investigated the canonical FoxO1-HMGA1-responsive IGFBP1 gene, whose hepatic expression is regulated by insulin. By using a conventional GST-pull down assay combined with co-immunoprecipitation and Fluorescence Resonance Energy Transfer (FRET) analyses, we provide evidence of a physical interaction between FoxO1 and HMGA1. Further investigation with chromatin immunoprecipitation, confocal microscopy, and Fluorescence Recovery After Photobleaching (FRAP) technology indicated a functional significance of this interaction, in both basal and insulin-stimulated states, providing evidence that, by modulating FoxO1 transactivation, HMGA1 is essential for FoxO1-induced IGFBP1 gene expression, and thereby a critical modulator of insulin-mediated FoxO1 regulation in the liver. Collectively, our findings highlight a novel FoxO1/HMGA1-mediated mechanism by which insulin may regulate gene expression and metabolism.

This is the second part of a two-part series that describes a pilot programming course in which high school students majoring in computer science were introduced to the visual, scenario-based programming language of live sequence charts. The main rationale for the course was that computer science students should be exposed to at least two very different programming paradigms and that LSCs, with their unique characteristics, can be a good vehicle for that. Part 1 (see the previous issue) focused on the pedagogic rationale of the pilot, on introducing LSC, and on the structure of the course. Part 2 centers on the evaluation of the pilot’s results.

This article describes a pilot programming course in which high school students were introduced, through the visual programming language of live sequence charts (LSC), to a new paradigm termed scenario-based programming. The rationale underlying this course was teaching high school students a second, very different programming paradigm. Using LSC for this purpose has other advantages, such as exposing students to high-level programming, dealing with nondeterminism and concurrency, and referring to human-computer interaction (HCI) issues. This work also contributes to the discussion about guiding principles for curriculum development. It highlights an important principle: the educational objective of a course should include more than mere knowledge enhancement. A course should be examined and justified through its contribution to learning fundamental ideas and forming useful habits of mind.