Culture, technology and local networks: towards a sociology of ‘making’ in education

This article is about ‘making’ in education. Often associated with software programming (as in ‘digital making’), making can also involve creating or modifying physical technological artefacts. In this paper, making is examined as a phenomenon that occurs at the intersection of culture, the economy, technology and education. The focus is not on the effects on cognitive gains or motivations, but on locating making in a social, historical and economic context. Making is also described as a form of ‘material connotation’, where connotation refers to the process through which the technical structure of artefacts is altered by culture and society. In the second part of the paper, the theoretical discussion is complemented by a case study in which making is described as a networked phenomenon where technology companies, consultants, volunteers, schools, and students were all implicated in turning a nebulous set of practices and discourses into an educational reality

Inheritance pattern of tetraploid Dioscorea alata and evidence of double reduction using microsatellite marker segregation analysis

Recent studies have shown that the basic chromosome number of the three major edible yams, Dioscorea alata, Dioscorea rotundata and Dioscorea trifida, is x = 20, and that the clones with 2n = 40 chromosomes are diploids. D. alata breeding programmes were limited to the production of diploid hybrids until 2006, when the tetraploids (2n = 80) were found to be fertile and polyploid hybrids were produced by conventional hybridisation. However, the nature of the polyploidy (autotetraploidy or allotetraploidy) was not known in D. alata tetraploid clones. In the present study, the inheritance pattern of simple sequence repeat markers was determined in a tetraploid progeny using a Bayesian approach and by examining double reduction events. Results obtained confirm the autotetraploid nature of the 2n = 80 clones of D. alata

Microsatellite and flow cytometry analysis to help understand the origin of Dioscorea alata polyploids

AGAP : équipe Génomique évolutive et gestion des populations (GE²pop)Dioscorea alata is a polyploid species with a ploidy level ranging from diploid (2n 2x 40) to tetraploid (2n 4x 80). Ploidy increase is correlated with better agronomic performance. The lack of knowledge about the origin of D. alata spontaneous polyploids (triploids and tetraploids) limits the efficiency of polyploid breeding. The objective of the present study was to use flow cytometry and microsatellite markers to understand the origin of D. alata polyploids. Different progeny generated by intracytotype crosses (2x 2x) and intercytotype crosses (2x 4x and 3x 2x) were analysed in order to understand endosperm incompatibility phenomena and gamete origins via the heterozygosity rate transmitted to progeny. This work shows that in a 2x 2x cross, triploids with viable seeds are obtained only via a phenomenon of diploid female non-gametic reduction. The study of the transmission of heterozygosity made it possible to exclude polyspermy and polyembryony as the mechanisms at the origin of triploids. The fact that no seedlings were obtained by a 3x 2x cross made it possible to confirm the sterility of triploid females. Flow cytometry analyses carried out on the endosperm of seeds resulting from 2x 4x crosses revealed endosperm incompatibility phenomena. The major conclusion is that the polyploids of D. alata would have appeared through the formation of unreduced gametes. The triploid pool would have been built and diversified through the formation of 2n gametes in diploid females as the result of the non-viability of seeds resulting from the formation of 2n sperm and of the non-viability of intercytotype crosses. The tetraploids would have appeared through bilateral sexual polyploidization via the union of two unreduced gametes due to the sterility of triploids

Magno- and parvocellular contrast responses in varying degrees of autistic trait

Autistic tendency has been associated with altered visual perception, especially impaired visual motion sensitivity and global/local integration, as well as enhanced visual search and local shape recognition. However, the neurophysiological mechanisms underlying these abnormalities remain poorly defined. The current study recruited 29 young adults displaying low, middle or high autistic trait as measured by Baron-Cohen's Autism spectrum Quotient (AQ), and measured motion coherence thresholds psychophysically, with manipulation of dot lifetime and stimulus contrast, as well as nonlinear cortical visual evoked potentials (VEPs) over a range of temporal luminance contrast levels from 10% to 95%. Contrast response functions extracted from the major first order and second order Wiener kernel peaks of the VEPs showed consistent variation with AQ group, and Naka-Rushton fits enabled contrast gain and semi-saturation contrasts to be elicited for each peak. A short latency second order response (previously associated with magnocellular processing) with high contrast gain and a saturating contrast response function showed higher amplitude for the High AQ (compared with Mid and Low groups) indicating poorer neural recovery after rapid stimulation. A non-linearity evoked at longer interaction times (previously associated with parvocellular processing) with no evidence of contrast saturation and lower contrast gain showed no difference between autism quotient groups across the full range of stimulus contrasts. In addition, the short latency first order response and a small, early second order second slice response showed gain and semi-saturation parameters indicative of magnocellular origin, while the longer latency first order response probably reflects a mixture of inputs (including feedback from higher cortical areas). Significant motion coherence (AQ group) * (dot lifetime) interactions with higher coherence threshold for limited dot lifetime stimuli is consistent with atypical magnocellular functioning, however psychophysical performance for those with High AQ is not explained fully, suggesting that other factors may be involved

Selective inhibition of the FcɛRI-induced de novo synthesis of mediators by an inhibitory receptor

Aggregation of the type 1 Fcɛ receptors (FcɛRI) on mast cells initiates a network of biochemical processes culminating in secretion of both granule-stored and de novo-synthesized inflammatory mediators. A strict control of this response is obviously a necessity; nevertheless, this regulation is hardly characterized. Here we report that a prototype inhibitory receptor, the mast cell function-associated antigen (MAFA), selectively regulates the FcɛRI stimulus–response coupling network and the subsequent de novo production and secretion of inflammatory mediators. Specifically, MAFA suppresses the PLC-γ2–[Ca(2+)](i), Raf-1–Erk1/2, and PKC–p38 coupling pathways, while the Fyn–Gab2-mediated activation of PKB and Jnk is essentially unaffected. Hence, the activities of several transcription/nuclear factors for inflammatory mediators (NF-κB, NFAT) are markedly reduced, while those of others (Jun, Fos, Fra, p90rsk) are unaltered. This results in a selective inhibition of gene transcription of cytokines including IL-1β, IL-4, IL-8, and IL-10, while that of TNF-α, MCP-1, IL-3, IL-5, or IL-13 remains unaffected. Taken together, these results illustrate the capacity of an immunoreceptor tyrosine-based inhibitory motif-containing receptor to cause tight and specific control of the production and secretion of inflammatory mediators by mast cells

Waveform Comparison.

<p>Comparison of the grand mean average waveforms for <b>a</b>: K1, <b>b</b>: K2.1 and <b>c</b>: K2.2 kernel responses recorded at 70% stimulus contrast. The mean waves for the High and Low AQ groups are shown with a fringe of ±1SE. Significant mean waveform departures (<i>p</i><.05) are indicated by asterisks.</p

Contrast response functions for five major peaks.

<p>Contrast response functions for High (red), Mid (blue) and Low (green) AQ groups for major peaks of the first order (K1) and first two slices of the second order (K2.1, K2.2) kernels. Mean amplitudes (with SE) are shown with Naka-Rushton fits for <b>a</b>: The initial N60P90 peak of the first order kernel K1, <b>b</b>: The N60P90 peak of the second order kernel – first slice K2.1, <b>c</b>: the small N60P75 peak of the second order kernel – second slice K2.2 <b>d</b>: the longer latency N125P160 peak for the first order kernel K1, <b>e</b>: the major N95P130 for K2.2. <b>f</b>: Hierarchical decomposition of the 15 contrast response functions on the basis of Semi-Saturation constant, Contrast Gain, and Peak Number shows a strong separation of waves previously attributed to magno and parvocellular origin.</p

Demographic details and AQ scores according to AQ group.

<p>Demographic details and AQ scores according to AQ group.</p