This paper draws upon a distinction between fundamental and derived senses of literacy to show that conceptions of scientific literacy attend to the derived sense but tend to neglect the fundamental sense. In doing so, they fail to address a central component of scientific literacy. A notion of literacy in its fundamental sense is elaborated and contrasted to a simple view of reading and writing that still has much influence on literacy instruction in schools and, we believe, is widely assumed in science education. We make suggestions about how scientific literacy would be viewed differently if the fundamental sense of literacy were taken seriously and explore some educational implications of attending to literacy in its fundamental sense when teaching science.

The kinesin-3 family is one of the largest among the kinesin superfamily and its members play important roles in a wide range of cellular transport activities, yet the molecular mechanisms of kinesin-3 regulation and cargo transport are largely unknown. We performed a comprehensive analysis of mammalian kinesin-3 motors from three different subfamilies (KIF1, KIF13, and KIF16). Using Forster resonance energy transfer microscopy in live cells, we show for the first time to our knowledge that KIF16B motors undergo cargo-mediated dimerization. The molecular mechanisms that regulate the monomer-to-dimer transition center around the neck coil (NC) segment and its ability to undergo intramolecular interactions in the monomer state versus intermolecular interactions in the dimer state. Regulation of NC dimerization is unique to the kinesin-3 family and in the case of KIF13A and KIF13B requires the release of a proline-induced kink between the NC and subsequent coiled-coil 1 segments. We show that dimerization of kinesin-3 motors results in superprocessive motion, with average run lengths of ∼10 μm, and that this property is intrinsic to the dimeric kinesin-3 motor domain. This finding opens up studies on the mechanistic basis of motor processivity. Such high processivity has not been observed for any other motor protein and suggests that kinesin-3 motors are evolutionarily adapted to serve as the marathon runners of the cellular world.microtubule | molecular motor | helical plot | intracellular transport

This paper deals with a number of conceptual and theoretical issues that underlie the proposal to employ narrative explanations in science education: What is narrative? What is explanation? and What is narrative explanation? In answering these questions, we develop a framework of narrative elements and characteristics of narrative explanations. Two possible examples of narrative explanation are presented and examined in light of the framework. This examination brings to light various conceptual and empirical questions related to the examples and to the larger issue of the use of examples like them in science instruction. The value of the framework lies partly in its power to point to such questions. The questions can guide a program of theoretical and empirical research into the psychological reality of the narrative form of explanation, the existence of narrative explanations in science, the use of narrative explanations in science teaching, and the nature and extent of the narrative effect upon which proposals for the use of narrative often are justified.

Cilia dysfunction underlies a class of human diseases with variable penetrance in different organ systems. Across eukaryotes, intraflagellar transport (IFT) facilitates cilia biogenesis and cargo trafficking, but our understanding of mammalian IFT is insufficient. Here we perform live analysis of cilia ultrastructure, composition and cargo transport in native mammalian tissue using olfactory sensory neurons. Proximal and distal axonemes of these neurons show no bias towards IFT kinesin-2 choice, and Kif17 homodimer is dispensable for distal segment IFT. We identify Bardet–Biedl syndrome proteins (BBSome) as bona fide constituents of IFT in olfactory sensory neurons, and show that they exist in 1:1 stoichiometry with IFT particles. Conversely, subpopulations of peripheral membrane proteins, as well as transmembrane olfactory signalling pathway components, are capable of IFT but with significantly less frequency and/or duration. Our results yield a model for IFT and cargo trafficking in native mammalian cilia and may explain the penetrance of specific ciliopathy phenotypes in olfactory neurons.

The purpose of this article is to provide a critical commentary of the physiological and psychological tools used in the evaluation of swimmers. The first-level evaluation should be the competitive performance itself, since it is at this juncture that all elements interplay and provide the 'highest form' of assessment. Competition video analysis of major swimming events has progressed to the point where it has become an indispensable tool for coaches, athletes, sport scientists, equipment manufacturers, and even the media. The breakdown of each swimming performance at the individual level to its constituent parts allows for comparison with the predicted or sought after execution, as well as allowing for comparison with identified world competition levels. The use of other 'on-going' monitoring protocols to evaluate training efficacy typically involves criterion 'effort' swims and specific training sets where certain aspects are scrutinised in depth. Physiological parameters that are often examined alongside swimming speed and technical aspects include oxygen uptake, heart rate, blood lactate concentration, blood lactate accumulation and clearance rates. Simple and more complex procedures are available for in-training examination of technical issues. Strength and power may be quantified via several modalities although, typically, tethered swimming and dry-land isokinetic devices are used. The availability of a 'swimming flume' does afford coaches and sport scientists a higher degree of flexibility in the type of monitoring and evaluation that can be undertaken. There is convincing evidence that athletes can be distinguished on the basis of their psychological skills and emotional competencies and that these differences become further accentuated as the athlete improves. No matter what test format is used (physiological, biomechanical or psychological), similar criteria of validity must be ensured so that the test provides useful and associative information concerning current or future performance. The practical worth of any proposed testing or monitoring protocol should be carefully evaluated. In addition, the developmental stage of the athlete(s) in question should be reflected in the testing/monitoring programme. Finally, increasing technological innovations will bring to the pool deck or dry-land training area simple, fast and advanced diagnostic tools, particularly in the areas of blood-borne markers of training response and neuromuscular excitability.