Les microARNs

MiRNAs are small non-coding RNAs ensuring the post-transcriptional regulation of gene expression. Their expression is tissue-specific and some miRNAs have diagnostic and / or prognostic value for tumor classes. MiRNAs are involved in tumorigenesis by two mechanisms: amplification or deletion of chromosomal regions containing clusters of genes encoding miRNAs (quantitative effect) or modification of the effects of miRNAs on their target genes by mutation in the region of interaction with the mRNA (qualitative effect). Their specificity, the possibility for miRNA measurement in blood, must now lead to consider miRNAs as markers for therapeutic management. A better understanding of the different regulatory mechanisms involving miRNAs will also consider new therapeutic approaches

Magnetic relaxation of exchange biased (Pt/Co) multilayers studied by time-resolved Kerr microscopy

Magnetization relaxation of exchange biased (Pt/Co)5/Pt/IrMn multilayers with perpendicular anisotropy was investigated by time-resolved Kerr microscopy. Magnetization reversal occurs by nucleation and domain wall propagation for both descending and ascending applied fields, but a much larger nucleation density is observed for the descending branch, where the field is applied antiparallel to the exchange bias field direction. These results can be explained by taking into account the presence of local inhomogeneities of the exchange bias field.Comment: To appear in Physical Review B (October 2005

Micro-ARNs dans les tumeurs folliculaires de la thyroïde

Key pointsMiRNAs are small noncoding RNA ensuring post-transcriptional regulation of gene expression. Their expression is tissue-specific and some miRNAs have diagnostic and/or prognostic interest for tumor classes. MiRNAs are involved in tumoral process in quantitative (amplification, deletion of chromosomal regions) or qualitative terms (mutation in the miRNA or in the corresponding site of interaction in the mRNA). Overexpression of three miRNAs (miR-146b, miR-221 and miR-222) correlates with the development of papillary thyroid tumors. Polymorphisms in the c-kit gene or in that encoding miR-146a are susceptibility factors for the development of papillary thyroid tumors. Points essentiels Les micro-ARNs (miRNAs) sont des petits ARN non codant assurant la régulation post-transcriptionnelle de l’expression génique. Leur expression est tissu-spécifique et certains miRNAs ont une valeur diagnostique et/ou pronostique de classes tumorales. Les miRNAs sont impliqués dans les processus tumoraux par deux mécanismes : amplification ou délétion de régions chromosomiques renfermant des clusters de gènes codant des miRNAs (effet quantitatif) ou modification des effets des miRNAs sur leur gènes cibles par mutation dans le site d’interaction avec les ARNm (effet qualitatif). La surexpression de trois miRNAs (miR-146b, miR-221 et miR-222) est corrélée au développement des tumeurs papillaires de la thyroïde. Des polymorphismes dans le gène c-Kit ou dans celui codant pour miR-146a sont des facteurs de susceptibilité au développement des tumeurs papillaires de la thyroïde

Interplay between magnetic anisotropy and interlayer coupling in nanosecond magnetization reversal of spin-valve trilayers

The influence of magnetic anisotropy on nanosecond magnetization reversal in coupled FeNi/Cu/Co trilayers was studied using a photoelectron emission microscope combined with x-ray magnetic circular dicroism. In quasi-isotropic samples the reversal of the soft FeNi layer is determined by domain wall pinning that leads to the formation of small and irregular domains. In samples with uniaxial magnetic anisotropy, the domains are larger and the influence of local interlayer coupling dominates the domain structure and the reversal of the FeNi layer

Statistically Motivated Second Order Pooling

Second-order pooling, a.k.a.~bilinear pooling, has proven effective for deep learning based visual recognition. However, the resulting second-order networks yield a final representation that is orders of magnitude larger than that of standard, first-order ones, making them memory-intensive and cumbersome to deploy. Here, we introduce a general, parametric compression strategy that can produce more compact representations than existing compression techniques, yet outperform both compressed and uncompressed second-order models. Our approach is motivated by a statistical analysis of the network's activations, relying on operations that lead to a Gaussian-distributed final representation, as inherently used by first-order deep networks. As evidenced by our experiments, this lets us outperform the state-of-the-art first-order and second-order models on several benchmark recognition datasets.Comment: Accepted to ECCV 2018. Camera ready version. 14 page, 5 figures, 3 table

Bonobo Conservation as a means for Local Development: an Innovative Local Initiative of Community-based Conservation in the DemocraticRepublic of the Congo

International audienceThe Democratic Republic of the Congo (DRC) ranks fifth in the world in terms of biodiversity (fauna and flora) and first for mammal diversity in Africa. There are numerous endemic species including bolobos (Pan paniscus). Bolobos are endangered, threatened mainly by deforestation, poaching and diseases, and the current population is estimated from 15,000 to 50,000 individuals. Nowadays, one national park (Salonga National Park) and six reserves exist for wild bolobo conservation, representing about 73,000 km2 of protected areas over an estimated distribution area of 565,000 km2. In the Bolobo Territory, an original local project of bolobo conservation was initiated in 2001 by the Congolese NGO Mbou-Mon-Tour (MMT). From 2008 to 2013, we studied bolobo-habitat-human interactions in this forest-savanna mosaic habitat, totalizing 12 months of survey over six periods. Besides eco-ethological studies, an ethnoecological approach was developed in order to better understand how the MMT project emerged and how it has evolved. We performed semi-structured interviews, participant observation, and informal discussions with local people. We also used grey literature associated to the region. MMT use the bolobo conservation as a means to reach local development goals, which is the opposite of what is frequent in the “community-based conservation” project managed by environmental NGOs. The location of the community forests and the rules established for regulating activities in these forests were decided by the villagers under the organization of traditional chiefs according to their knowledge on bolobo ecology and range, and the disturbance they perceived of the traditional activities in the forest. Such a process is a novel and promising approach for wildlife conservation that maintains the place of local people and traditional authorities in the decision-making process and the governance

Estrogen-related receptor α and PGC-1-related coactivator constitute a novel complex mediating the biogenesis of functional mitochondria

Mitochondrial biogenesis, which depends on nuclear as well as mitochondrial genes, occurs in response to increased cellular ATP demand. The nuclear transcriptional factors, estrogen-related receptor α (ERRα) and nuclear respiratory factors 1 and 2, are associated with the coordination of the transcriptional machinery governing mitochondrial biogenesis, whereas coactivators of the peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) family serve as mediators between the environment and this machinery. In the context of proliferating cells, PGC-1-related coactivator (PRC) is a member of the PGC-1 family, which is known to act in partnership with nuclear respiratory factors, but no functional interference between PRC and ERRα has been described so far. We explored three thyroid cell lines, FTC-133, XTC.UC1 and RO 82 W-1, each characterized by a different mitochondrial content, and studied their behavior towards PRC and ERRα in terms of respiratory efficiency. Overexpression of PRC and ERRα led to increased respiratory chain capacity and mitochondrial mass. The inhibition of ERRα decreased cell growth and respiratory chain capacity in all three cell lines. However, the inhibition of PRC and ERRα produced a greater effect in the oxidative cell model, decreasing the mitochondrial mass and the phosphorylating respiration, whereas the nonphosphorylating respiration remained unchanged. We therefore hypothesize that the ERRα–PRC complex plays a role in arresting the cell cycle through the regulation of oxidative phosphorylation in oxidative cells, and through some other pathway in glycolytic cells

Second-order Democratic Aggregation

Aggregated second-order features extracted from deep convolutional networks have been shown to be effective for texture generation, fine-grained recognition, material classification, and scene understanding. In this paper, we study a class of orderless aggregation functions designed to minimize interference or equalize contributions in the context of second-order features and we show that they can be computed just as efficiently as their first-order counterparts and they have favorable properties over aggregation by summation. Another line of work has shown that matrix power normalization after aggregation can significantly improve the generalization of second-order representations. We show that matrix power normalization implicitly equalizes contributions during aggregation thus establishing a connection between matrix normalization techniques and prior work on minimizing interference. Based on the analysis we present {\gamma}-democratic aggregators that interpolate between sum ({\gamma}=1) and democratic pooling ({\gamma}=0) outperforming both on several classification tasks. Moreover, unlike power normalization, the {\gamma}-democratic aggregations can be computed in a low dimensional space by sketching that allows the use of very high-dimensional second-order features. This results in a state-of-the-art performance on several datasets