Teaching addition and subtraction by the method of bidirectional translation: an empirical study

Bidirectional Translation, devised by the author, is a structured approach to the teaching of addition and subtraction which aims to give children greater understanding of arithmetical operations. The approach systematically involves both: the translation of numerical representations into hypothetical, real world contexts; and the extraction of the appropriate numerical operations from hypothetical, real world contexts. It is this emphasis on translation from and to both the numerical representation and realistic contexts which gives rise to the name, Bidirectional Translation. An experimental group of 90 primary one children were taught to add and subtract (within 10) by the method of Bidirectional Translation. Post-test comparison of the experimental subjects' performance with that of a control group showed significantly superior performance on the part of the experimental subjects in terms of the utilizability of addition, the evocability of addition, the utilizability of subtraction and the evocability of subtraction for five different classes of verbal context, namely: Part-Part Whole, Separating, Joining, Equalizing and Comparison contexts. In all instances the probability of the results being chance ones were less than 5% and in most, were less than 1%. In both the experimental and control groups, most children performed better when they were required to utilize concepts than when they were required to evoke concepts. Similarly they performed better when they were required to add than when they were required to subtract. The differences, however, were not always significant. It is suggested that the effectiveness of the methodology of Bidirectional Translation is rooted in a structure which allows the child to make his/her thinking explicit and which allows the teacher to monitor this

Deducing topology of protein-protein interaction networks from experimentally measured sub-networks.

BackgroundProtein-protein interaction networks are commonly sampled using yeast two hybrid approaches. However, whether topological information reaped from these experimentally-measured sub-networks can be extrapolated to complete protein-protein interaction networks is unclear.ResultsBy analyzing various experimental protein-protein interaction datasets, we found that they are not random samples of the parent networks. Based on the experimental bait-prey behaviors, our computer simulations show that these non-random sampling features may affect the topological information. We tested the hypothesis that a core sub-network exists within the experimentally sampled network that better maintains the topological characteristics of the parent protein-protein interaction network. We developed a method to filter the experimentally sampled network to result in a core sub-network that more accurately reflects the topology of the parent network. These findings have fundamental implications for large-scale protein interaction studies and for our understanding of the behavior of cellular networks.ConclusionThe topological information from experimental measured networks network as is may not be the correct source for topological information about the parent protein-protein interaction network. We define a core sub-network that more accurately reflects the topology of the parent network

Size-tuneable nanometric MRI contrast agents for the imaging of molecular weight dependent transport processes

Purpose: To evaluate size-tuneable nanomeric glycol-chitosan-DTPA-Gd conjugates as MRI contrast agents for the imaging of molecular weight (MW) dependent transport processes. Material & Methods: Glycol chitosans (GC) – DTPA conjugates of precisely controlled MWs were synthesised and evaluated in mice against Gd-DTPA using times series of high-resolution MRI images of trunk, head, and xenograft flank tumours. All animal studies were approved by the local ethics committee and the UK authorities. Results: GC-DTPA modification ratio was one DTPA per 3.9 – 5.13 of GC monomers. GC-DTAPGd provided overall superior contrast compared to Gd-DTPA with the duration of the enhancement depending on MW (≥ 1h for 40kD). Kidneys showed early enhancement also in the renal pelvis suggesting renal elimination. Imaging of the head with GC-DTPA-Gd allowed detailed anatomical identification of specific blood vessels in particular with the high MW agent. Sequential high-resolution isotropic imaging of established A431 xenograft flank tumours with DTPA-Gd and GC-DTPA-Gd demonstrated that the initial delivery of the contrast agents was well correlated with blood supply. Subsequent tissue transport was primarily by diffusion and was limited by molecular weight. The data also highlight the role of heterogeneity in CA distribution that was again more prominent for the high MW agent. Conclusion: GC-DTPA-Gd with identical physical chemical properties but precisely controlled MW allow isotropic high-resolution three-dimensional imaging of molecular weight dependent transport processes which could potentially lead to clinical biomarkers for molecular weight dependent drug transport and support selection of suitable tumour models for pre-clinical development

Practising critical resilience as an advanced peer support worker in London: A qualitative evaluation of a peer-led hepatitis C intervention amongst people experiencing homelessness who inject drugs

Background: Peer support has been used as a mechanism to facilitate active engagement with healthcare amongst underserved populations. The HepCare project upskilled experienced peer support workers (PSWs) to become equal members of a service provider team, taking on advanced clinical roles normally carried out by medical or nursing specialists. Method: A participatory case study approach was taken to the study following the methodological guidance of Merriam (1998). The subject of the case in our study is the advanced peer support workers (APSWs) functioning in the HepCare project as service providers. The object of the case is an exploration of their transition to service provider in the HCV screening and treatment support service. Five peer led in-depth interviews with APSWs were supplemented by a survey of health professionals, interviews with service users, documentary evidence in the form of job descriptions, observational notes and a blog from the field. Thematic analysis of the data was conducted, refined and finalised in a workshop with the research team and APSW participants. Results Three themes were generated from the data that explore the peer support worker's transition to APSW in the programme: Transition to Integration, Retaining ‘Peerness’, and Practising Critical Resilience. The advocacy and support enacted by the APSWs through the HepCare project, offer purpose and meaning alongside integration into a new social group. This is buffered by the supportive context of the programme and facilitates a motivating sense of worth. Conclusion: The programme offers policy guidance for the structured career development of APSWs and a platform for enactment of critical resilience as they transition to their advanced role, in the healthcare provider team

Coupling of upper and lower limb pattern generators during human crawling at different arm/leg speed combinations

A crawling paradigm was performed by healthy adults to examine inter-limb coupling patterns and to understand how central pattern generators (CPGs) for the upper and lower limbs are coordinated. Ten participants performed hands-and-feet crawling on two separate treadmills, one for the upper limbs and another one for the lower limbs, the speed of each of them being changed independently. A 1:1 frequency relationship was often maintained even when the treadmill speed was not matched between the upper and lower limbs. However, relative stance durations in the upper limbs were only affected by changes of the upper limb treadmill speed, suggesting that although absolute times are adjusted, the relative proportions of stances and swing do not adapt to changes in lower limb treadmill speeds. With large differences between treadmill speeds, changes in upper and lower limb coupling ratio tended to occur when the upper limbs stepped at slower speeds than the lower limbs, but more rarely the other way around. These findings are in sharp contrast with those in the cat, where forelimbs always follow the rhythm of the faster moving hindlimbs. However, the fact that an integer frequency ratio is often maintained between the upper and lower limbs supports evidence of coupled CPG control. We speculate that the preference for the upper limb to decrease step frequency at lower speeds in humans may be due to weaker ascending propriospinal connections and/or a larger influence of cortical control on the upper limbs which allows for an overriding of spinal CPG control

Locomotor-like leg movements evoked by rhythmic arm movements in humans

Motion of the upper limbs is often coupled to that of the lower limbs in human bipedal locomotion. It is unclear, however, whether the functional coupling between upper and lower limbs is bi-directional, i.e. whether arm movements can affect the lumbosacral locomotor circuitry. Here we tested the effects of voluntary rhythmic arm movements on the lower limbs. Participants lay horizontally on their side with each leg suspended in an unloading exoskeleton. They moved their arms on an overhead treadmill as if they walked on their hands. Hand-walking in the antero-posterior direction resulted in significant locomotor-like movements of the legs in 58% of the participants. We further investigated quantitatively the responses in a subset of the responsive subjects. We found that the electromyographic (EMG) activity of proximal leg muscles was modulated over each cycle with a timing similar to that of normal locomotion. The frequency of kinematic and EMG oscillations in the legs typically differed from that of arm oscillations. The effect of hand-walking was direction specific since medio-lateral arm movements did not evoke appreciably leg air-stepping. Using externally imposed trunk movements and biomechanical modelling, we ruled out that the leg movements associated with hand-walking were mainly due to the mechanical transmission of trunk oscillations. EMG activity in hamstring muscles associated with hand-walking often continued when the leg movements were transiently blocked by the experimenter or following the termination of arm movements. The present results reinforce the idea that there exists a functional neural coupling between arm and legs

Flexible access to conformationally-locked bicyclic morpholines

A preparatively accessible route to a series of conformationally-locked bicyclic morpholines has been developed. This flexible approach allows for diversification in order for a small array of lead-like scaffolds to be synthesised from readily available key building blocks

Experienced tutors' deployment of thinking skills and what might be entailed in enhancing such skills

In the context of research that reports weaknesses in adults' critical thinking skills, the primary aim was to examine adults' use of critical thinking skills that are described in taxonomies and to identify areas for development. Position papers written by an opportunity sample of 32 experienced adult educators formed the data for a descriptive sample survey design intended to reveal participants' use of critical thinking skills. Each 6000-word paper was written during a development programme that supported such skills. A content analysis of the papers revealed that when participants drew on personal and published ideas about learning to derive their proposals for change, they accepted the ideas uncritically, thereby implying that they might find it difficult to help learners to examine ideas critically. The evidence supports research that implies that critical thinking skills are unlikely to develop unless overall course design privileges the development of epistemological understanding (King and Kitchener 1994, Kuhn 1999). A fundamental assumption underlying the study is that this understanding influences effective citizenship and personal development, as well as employability. A proposition that merits attention in future research is that the development of epistemological understanding is largely neglected in current curricula in formal post-16 education