S'informer entre deux regards. Compétences médiatiques des jeunes issus de l’immigration

Ayant grandi entre deux cultures différentes, les jeunes issus de l’immigration développent des compétences médiatiques spécifiques. Les nouveaux médias, et surtout Internet, leur permettent d’atteindre des sources alternatives d’information, et de maintenir ainsi un lien avec leur pays d'origine. Le recours à Internet constitue pour eux une remise en cause radicale de l’organisation mentale des contenus : réfléchir aux nouvelles qui proviennent de loin devient une véritable manière de penser. L'analyse des usages d’Internet par ces jeunes renvoie aux compétences médiatiques qui devraient être acquises par toute la communauté juvénile. L’objectif de cet article est de comprendre la nature de ces compétences et le rôle de l’éducation aux médias dans leur sollicitation. Pour répondre à ces questions, l'article présente les résultats d’une recherche ethnographique menée dans la ville de Milan, et avance quelques propositions pour l’éducation aux médias des jeunes générations.Ayant grandi entre deux cultures différentes, les jeunes issus de l’immigration développent des compétences médiatiques spécifiques. Les nouveaux médias, et surtout Internet, leur permettent d’atteindre des sources alternatives d’information, et de maintenir ainsi un lien avec leur pays d'origine. Le recours à Internet constitue pour eux une remise en cause radicale de l’organisation mentale des contenus : réfléchir aux nouvelles qui proviennent de loin devient une véritable manière de penser. L'analyse des usages d’Internet par ces jeunes renvoie aux compétences médiatiques qui devraient être acquises par toute la communauté juvénile. L’objectif de cet article est de comprendre la nature de ces compétences et le rôle de l’éducation aux médias dans leur sollicitation. Pour répondre à ces questions, l'article présente les résultats d’une recherche ethnographique menée dans la ville de Milan, et avance quelques propositions pour l’éducation aux médias des jeunes générations

Travels of a Rayed Head: imagery, fiber, structure and connotations of early textiles from the South Central Andes

The rayed head image has long been identified as a central symbol associated with the Paracas tradition, also called the sun face 1 and associated with the concept of Oculate Being developed by the Berkeley School. 2 Prominently repeated on the central ground of the famous Paracas Textile at the Brooklyn Museum, this image has much earlier antecedents in the region. Scholars disagree on the extent to which many Paracas, Topara and early Nasca images with large round eyes, grinning mouths, and serpentlike appendages emitting from the head and body may also be manifestations of a particular Oculate Being or of more general concepts of natural or supernatural power. Recently, contemporary textiles found in the Sihuas valley to the south (see Haeberli in this volume) challenge us to reexamine the similarities and distinctions among rayed heads. One of the great challenges of the history of material culture, envisioned as a history of philosophical concepts, social values and cultural practices through their inscription in material objects, is the degree to which a recurrent image, pattern or special arrangement reflects a similar idea. A number of quite different images have been associated with the concept of an Oculate Being proposed by John Rowe and others of the Berkeley school based on their analysis of Ica valley ceramics and Ocucaje gravelots in the 1950s. I here trace the rayed head or sun face image as it occurs over at least 500 years in the region of Ica and Paracas. I then briefly consider its relationship to other contemporary imagery and later imagery featuring ray-like elements emitted from the head, both in the same contexts where the rayed head appears, and in other cemeteries to the south in southern Peru and northern Chile. All the imagery discussed here is associated with a period between about 450 BC and AD 450 called the Formative in the South Central Andes (Bolivia and northern Chile) and called the Early Horizon (or late Formative) and Early Intermediate (or Regional Development) Period in the Central Andes. Most of the images I discuss are created on textiles. While only recovered from burials on the desert coast, textile materials draw on relationships of production and exchange that spanned the Andean cordillera to the montane rainforest to the east, and stretched to the north and south. Either as clothing or cargo, textiles themselves traveled and were no doubt a primary source of non-local imagery. I do consider related images on non-textile artifacts. I compare textile based imagery with contemporary imagery on engraved and painted ceramics and gourds to try to distinguish among design features specific to medium, style and iconography

Histone methyltransferase Dot1 and Rad9 inhibit single-stranded DNA accumulation at DSBs and uncapped telomeres

Cells respond to DNA double-strand breaks (DSBs) and uncapped telomeres by recruiting checkpoint and repair factors to the site of lesions. Single-stranded DNA (ssDNA) is an important intermediate in the repair of DSBs and is produced also at uncapped telomeres. Here, we provide evidence that binding of the checkpoint protein Rad9, through its Tudor domain, to methylated histone H3-K79 inhibits resection at DSBs and uncapped telomeres. Loss of DOT1 or mutations in RAD9 influence a Rad50-dependent nuclease, leading to more rapid accumulation of ssDNA, and faster activation of the critical checkpoint kinase, Mec1. Moreover, deletion of RAD9 or DOT1 partially bypasses the requirement for CDK1 in DSB resection. Interestingly, Dot1 contributes to checkpoint activation in response to low levels of telomere uncapping but is not essential with high levels of uncapping. We suggest that both Rad9 and histone H3 methylation allow transmission of the damage signal to checkpoint kinases, and keep resection of damaged DNA under control influencing, both positively and negatively, checkpoint cascades and contributing to a tightly controlled response to DNA damage

RNAi Screening Implicates a SKN-1-Dependent Transcriptional Response in Stress Resistance and Longevity Deriving from Translation Inhibition

Caenorhabditis elegans SKN-1 (ortholog of mammalian Nrf1/2/3) is critical for oxidative stress resistance and promotes longevity under reduced insulin/IGF-1-like signaling (IIS), dietary restriction (DR), and normal conditions. SKN-1 inducibly activates genes involved in detoxification, protein homeostasis, and other functions in response to stress. Here we used genome-scale RNA interference (RNAi) screening to identify mechanisms that prevent inappropriate SKN-1 target gene expression under non-stressed conditions. We identified 41 genes for which knockdown leads to activation of a SKN-1 target gene (gcs-1) through skn-1-dependent or other mechanisms. These genes correspond to multiple cellular processes, including mRNA translation. Inhibition of translation is known to increase longevity and stress resistance and may be important for DR-induced lifespan extension. One model postulates that these effects derive from reduced energy needs, but various observations suggest that specific longevity pathways are involved. Here we show that translation initiation factor RNAi robustly induces SKN-1 target gene transcription and confers skn-1-dependent oxidative stress resistance. The accompanying increases in longevity are mediated largely through the activities of SKN-1 and the transcription factor DAF-16 (FOXO), which is required for longevity that derives from reduced IIS. Our results indicate that the SKN-1 detoxification gene network monitors various metabolic and regulatory processes. Interference with one of these processes, translation initiation, leads to a transcriptional response whereby SKN-1 promotes stress resistance and functions together with DAF-16 to extend lifespan. This stress response may be beneficial for coping with situations that are associated with reduced protein synthesis

S'informer entre deux regards. Compétences médiatiques des jeunes issus de l’immigration

Ayant grandi entre deux cultures différentes, les jeunes issus de l’immigration développent des compétences médiatiques spécifiques. Les nouveaux médias, et surtout Internet, leur permettent d’atteindre des sources alternatives d’information, et de maintenir ainsi un lien avec leur pays d'origine. Le recours à Internet constitue pour eux une remise en cause radicale de l’organisation mentale des contenus : réfléchir aux nouvelles qui proviennent de loin devient une véritable manière de penser. L'analyse des usages d’Internet par ces jeunes renvoie aux compétences médiatiques qui devraient être acquises par toute la communauté juvénile. L’objectif de cet article est de comprendre la nature de ces compétences et le rôle de l’éducation aux médias dans leur sollicitation. Pour répondre à ces questions, l'article présente les résultats d’une recherche ethnographique menée dans la ville de Milan, et avance quelques propositions pour l’éducation aux médias des jeunes générations

Phosphorylation of the Budding Yeast 9-1-1 Complex Is Required for Dpb11 Function in the Full Activation of the UV-Induced DNA Damage Checkpoint▿ †

Following genotoxic insults, eukaryotic cells trigger a signal transduction cascade known as the DNA damage checkpoint response, which involves the loading onto DNA of an apical kinase and several downstream factors. Chromatin modifications play an important role in recruiting checkpoint proteins. In budding yeast, methylated H3-K79 is bound by the checkpoint factor Rad9. Loss of Dot1 prevents H3-K79 methylation, leading to a checkpoint defect in the G1 phase of the cell cycle and to a reduction of checkpoint activation in mitosis, suggesting that another pathway contributes to Rad9 recruitment in M phase. We found that the replication factor Dpb11 is the keystone of this second pathway. dot1Δ dpb11-1 mutant cells are sensitive to UV or Zeocin treatment and cannot activate Rad53 if irradiated in M phase. Our data suggest that Dpb11 is held in proximity to damaged DNA through an interaction with the phosphorylated 9-1-1 complex, leading to Mec1-dependent phosphorylation of Rad9. Dpb11 is also phosphorylated after DNA damage, and this modification is lost in a nonphosphorylatable ddc1-T602A mutant. Finally, we show that, in vivo, Dpb11 cooperates with Dot1 in promoting Rad9 phosphorylation but also contributes to the full activation of Mec1 kinase