Teaching Sodium Fast Reactors in CEA

International audienceAmong the Fast Neutron Reactor Systems, the SFR has the most comprehensive technological basis as result of the experience gained from worldwide operation of several experimental, prototype, and commercial size reactors since the 1940s. This experience corresponds to about 402 years of operation by end of 2010. Six reactors are in operation BOR60, BN600 and BN800 in Russia, Joyo in Japan, FBTR in India and CEFR in China. One reactor is being commissioned PFBR (500MWe) in India and several projects are currently developed FBR1 and 2 in India, BN1200 in Russia, JSFR in Japan, PGSFR in Korea, CFR-600 in China and ASTRID in France. In order to support operation of existing reactors, design activities for new projects and decommissioning of old reactors, it is mandatory to develop skills, more particularly among the young generation, who will operate these new reactors. In addition, education and training is also essential to share the knowledge among the teams involved in Research and Development. Several strategies are developed at the national level, or within multilateral framework, like EU or IAEA to support development of Fast Reactors.In France, to answer to this increasing demand of Education and Training, four sessions are proposed, within the frame of INSTN (French National Institute for Nuclear Science and Technology)-SFR History, main options, design and operational feedback-SFR Functional analysis and design-SFR Safety and operation-SFR Sodium structures interactionsThe French Na School (ESML) provides since 1975 also several sessions dedicated to Na facilities design, safe operation, handling, and also decommissioning and sodium treatment. Beside courses, practical exercises are organized during each session. 10 different modules are available, ranging in length from 1 to 5 days. CEA contributes also to the organization of European Sessions dedicated to Sodium Fast Reactors, organized within the frame of the European Commission (CP-ESFR, ESNII+ , ESFR-SMART) This Education and Training strategy is a key element for the future of the development of Sodium Fast Reactors, and more particularly ASTRID project. CEA is ready to share training experience and to collaborate with other foreign Education and Training Entities

Quality of Experience in UHD-1 Phase 2 television: the contribution of UHD+ HFR technology

A key factor to determine the quality of experience (QoE) of a video is its capability to convey the large spectrum of perceptual phenomena that our eyes can sense in real life. In order to meet this demand, the recent DVB UHD-1 Phase 2 specification employs new video features, such as higher spatial resolutions (4K/8K) and High Frame Rate (HFR). The first enables larger field of view and level of details, while the second offers sharper images of moving objects going well beyond the current frame rates. While the contribution of each of these technologies to QoE has been investigated individually, in this paper we are interested to study their interaction, and in quantifying the benefits to users from their combination. To this end, we conduct a subjective test on compressed UHD+HFR content on a recent display capable of reproducing 100 pictures per second at 2160p resolution, with the goal to assess the increase in QoE of UHD and HFR with respect to conventional video, both individually and in combination. The results indicate that for content with fast motion, at higher bitrates the combination of UHD and HFR significantly improves the QoE compared to that obtained when these features are used individually

Assessment of the role of transcript for GATA-4 as a marker of unfavorable outcome in human adrenocortical neoplasms

BACKGROUND: Malignant neoplasia of the adrenal cortex is usually associated with very poor prognosis. When adrenocortical neoplasms are diagnosed in the early stages, distinction between carcinoma and adenoma can be very difficult to accomplish, since there is yet no reliable marker to predict tumor recurrence or dissemination. GATA transcription factors play an essential role in the developmental control of cell fate, cell proliferation and differentiation, organ morphogenesis, and tissue-specific gene expression. Normal mouse adrenal cortex expresses GATA-6 while its malignant counterpart only expresses GATA-4. The goal of the present study was to assess whether this reciprocal change in the expression of GATA factors might be relevant for predicting the prognosis of human adrenocortical neoplasms. Since human adrenal cortices express luteinizing hormone (LH/hCG) receptor and the gonadotropins are known to up-regulate GATA-4 in gonadal tumor cell lines, we also studied the expression of LH/hCG receptor. METHODS: We conducted a study on 13 non-metastasizing (NM) and 10 metastasizing/recurrent (MR) tumors obtained from a group of twenty-two adult and pediatric patients. The expression of GATA-4, GATA-6, and LH/hCG receptor (LHR) in normal and tumoral human adrenal cortices was analysed using reverse transcriptase-polymerase chain reaction (RT-PCR) complemented by dot blot hybridization. RESULTS: Messenger RNA for GATA-6 was detected in normal adrenal tissue, as well as in the totality of NM and MR tumors. GATA-4, by its turn, was detected in normal adrenal tissue, in 11 out of 13 NM tumors, and in 9 of the 10 MR tumors, with larger amounts of mRNA found among those presenting aggressive clinical behavior. Transcripts for LH receptor were observed both in normal tissue and neoplasms. A more intense LHR transcript accumulation was observed on those tumors with better clinical outcome. CONCLUSION: Our data suggest that the expression of GATA-6 in human adrenal cortex is not affected by tumorigenesis. GATA-4 expression is more abundant in MR tumors, while NM tumors express more intensely LHR. Further studies with larger cohorts are needed to test whether relative expression levels of LHR or GATA-4 might be used as prognosis predictors

Using LES to Study Reacting Flows and Instabilities in Annular Combustion Chambers

Great prominence is put on the design of aeronautical gas turbines due to increasingly stringent regulations and the need to tackle rising fuel prices. This drive towards innovation has resulted sometimes in new concepts being prone to combustion instabilities. In the particular field of annular combustion chambers, these instabilities often take the form of azimuthal modes. To predict these modes, one must compute the full combustion chamber, which remained out of reach until very recently and the development of massively parallel computers. Since one of the most limiting factors in performing Large Eddy Simulation (LES) of real combustors is estimating the adequate grid, the effects of mesh resolution are investigated by computing full annular LES of a realistic helicopter combustion chamber on three grids, respectively made of 38, 93 and 336 million elements. Results are compared in terms of mean and fluctuating fields. LES captures self-established azimuthal modes. The presence and structure of the modes is discussed. This study therefore highlights the potential of LES for studying combustion instabilities in annular gas turbine combustors

Profiling allele-specific gene expression in brains from individuals with autism spectrum disorder reveals preferential minor allele usage.

One fundamental but understudied mechanism of gene regulation in disease is allele-specific expression (ASE), the preferential expression of one allele. We leveraged RNA-sequencing data from human brain to assess ASE in autism spectrum disorder (ASD). When ASE is observed in ASD, the allele with lower population frequency (minor allele) is preferentially more highly expressed than the major allele, opposite to the canonical pattern. Importantly, genes showing ASE in ASD are enriched in those downregulated in ASD postmortem brains and in genes harboring de novo mutations in ASD. Two regions, 14q32 and 15q11, containing all known orphan C/D box small nucleolar RNAs (snoRNAs), are particularly enriched in shifts to higher minor allele expression. We demonstrate that this allele shifting enhances snoRNA-targeted splicing changes in ASD-related target genes in idiopathic ASD and 15q11-q13 duplication syndrome. Together, these results implicate allelic imbalance and dysregulation of orphan C/D box snoRNAs in ASD pathogenesis

Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST) cohort

Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs) of the imprinted Insulin-like Growth Factor 2 (IGF2) gene

TNOs are Cool: A survey of the trans-Neptunian region. VIII. Combined Herschel PACS and SPIRE observations of nine bright targets at 70–500 μm

International audienceAims. Trans-Neptunian objects (TNOs) are bodies populating the Kuiper belt and they are believed to retain the most pristine and least altered material of the solar system. The Herschel open time key programme entitled “TNOs are Cool: A survey of the trans-Neptunian region” has been awarded 373 h to investigate the albedo, size distribution and thermal properties of TNOs and Centaurs. Here we focus on the brightest targets observed by both the PACS and SPIRE multiband photometers: the dwarf planet Haumea, six TNOs (Huya, Orcus, Quaoar, Salacia, 2002 UX25, and 2002 TC302), and two Centaurs (Chiron and Chariklo).Methods. Flux densities are derived from PACS and SPIRE instruments using optimised data reduction methods. The spectral energy distribution obtained with the Herschel PACS and SPIRE instruments over 6 bands (centred at 70, 100, 160, 250, 350, and 500 μm), with Spitzer-MIPS at 23.7 and 71.4 μm, and with WISE at 11.6 and 22.1 μm in the case of 10199 Chariklo, has been modelled with the NEATM thermal model in order to derive the albedo, diameter, and beaming factor. For the Centaurs Chiron and Chariklo and for the 1000 km sized Orcus and Quaoar, a thermophysical model was also run to better constrain their thermal properties.Results. We derive the size, albedo, and thermal properties, including thermal inertia and surface emissivity, for the 9 TNOs and Centaurs. Several targets show a significant decrease in their spectral emissivity longwards of ~300 μm and especially at 500 μm. Using our size estimations and the mass values available in the literature, we also derive the bulk densities for the binaries Quaoar/Weywot (2.18-0.36+0.43 g/cm3), Orcus/Vanth (1.53-0.13+0.15 g/cm3), and Salacia/Actea (1.29-0.23+0.29 g/cm3). Quaoar’s density is similar to that of the other dwarf planets Pluto and Haumea, and its value implies high contents of refractory materials mixed with ices