157 research outputs found
Status of the low beta 0.07 cryomodules for SPIRAL2
International audienceThe status of the low beta cryomodules for SPIRAL2, supplied by the Irfu institute of CEA Saclay, is reported in this paper. We summarise in three parts the RF tests performed on the cavities in vertical cryostat, the RF power tests of the qualifying cryomodule performed in 2010 and the RF power tests performed in 2011 on the first cryomodule of the serie
SPIRAL2 RFQ prototype - First results
JACoW web site MOPCH103International audienceThe SPIRAL2 RFQ is designed to accelerate either 5 mA deuteron beam (Q/A=1/2) or a 1 mA of q/A=1/3 particle up to 0.75 MeV/A at 88 MHz. It is a CW machine which has to show stable operation, provide the required availability and reduce losses to a minimum in order to minimize the activation constraints. Extensive modelisation was done to ensure a good vane position under RF. The prototype of this 4-vane RFQ was built and tested in INFN-LNS Catania and then in IN2P3-LPSC Grenoble. It allowed us to measure the vacuum quality, the RF field by X-ray measurements, the cavity displacement and the real vane displacement during the RF injection. Different techniques were used, including an innovative CCD measurement with a 0.8 μm precision. This paper outlines the different results
Finite Theories and the SUSY Flavor Problem
We study a finite SU(5) grand unified model based on the non-Abelian discrete
symmetry A_4. This model leads to the democratic structure of the mass matrices
for the quarks and leptons. In the soft supersymmetry breaking sector, the
scalar trilinear couplings are aligned and the soft scalar masses are
degenerate, thus solving the SUSY flavor problem.Comment: 17 pages, LaTeX, 1 figur
Memòria Digital de Catalunya
Localització: Barcelona, Biblioteca de Catalunya, ms. 1102/7 (f. 172-199)Núm. 318, a la port. ms.A port.: "Estrenat en lo Circo Dramatich de Sta. Coloma de Farnés, lo dia de cap de any"A la port. i f. 175, segell de goma en tinta negra: "Teatro Enrique Antiga y Bas"Nom de l'autor obtingut a partir de les ed. de l'obra: Jaume Piquet i RieraF. 173 en blancAcotacions en un requadreFuente de ingreso: Compra a Elisa Castells, Vda. de Joan Almirall i Forast
A revised method for estimating hepatitis B virus transfusion residual risk based on antibody to hepatitis B core antigen incident cases
BACKGROUND: To take into account the transient nature of hepatitis B virus (HBV) antigenemia, the calculation of HBV residual risk (RR), based on the incidence/window period model, is adjusted by a correction factor that adds uncertainty to the RR estimates. STUDY DESIGN AND METHODS: This new method to estimate the RR for HBV is a weighted sum of the RR derived from hepatitis B surface antigen (HBsAg) incident cases and the one derived from antibody hepatitis B core antigen (HBc) incident cases. An anti-HBc incident case was defined as a donation from a blood donor who had made at least one anti-HBc–negative donation followed by a donation that was found positive with two different assays within a 3-year period and positive for at least one of the following markers: 1) antibody to hepatitis B e antigen or hepatitis B e antigen, 2) anti-HBc immunoglobulin M, 3) HBV DNA, 4) hepatitis B surface antibody without HBV vaccination history, or 5) HBV DNA retrospectively found in the previous donation. Five overlapping 3-year study periods between 2000 and 2006 were analyzed. RESULTS: The HBV RR estimated with the classical method ranged from 1.51 (2000-2002) to 0.69 per million donations in 2004 through 2006 with a decrease in 2002 through 2004 due to only two HBsAg incident cases reported in this period. By applying the revised model, the HBV RR ranged from 1.06 (2000-2002) to 0.49 per million donations (2004-2006), with a regular decrease. CONCLUSION: The new presented model provides HBV RR estimates that do not statistically differ from those obtained with the classical model; however, it provides more accurate data, especially in low endemic areas where the HBsAg incidence is low
3640 Unique EST Clusters from the Medaka Testis and Their Potential Use for Identifying Conserved Testicular Gene Expression in Fish and Mammals
BACKGROUND: The fish medaka is the first vertebrate capable of full spermatogenesis in vitro from self-renewing spermatogonial stem cells to motile test-tube sperm. Precise staging and molecular dissection of this process has been hampered by the lack of suitable molecular markers. METHODOLOGY AND PRINCIPAL FINDINGS: We have generated a normalized medaka testis cDNA library and obtained 7040 high quality sequences representing 3641 unique gene clusters. Among these, 1197 unique clusters are homologous to known genes, and 2444 appear to be novel genes. Ontology analysis shows that the 1197 gene products are implicated in diverse molecular and cellular processes. These genes include markers for all major types of testicular somatic and germ cells. Furthermore, markers were identified for major spermatogenic stages ranging from spermatogonial stem cell self-renewal to meiosis entry, progression and completion. Intriguingly, the medaka testis expresses at least 13 homologs of the 33 mouse X-chromosomal genes that are enriched in the testis. More importantly, we show that key components of several signaling pathways known to be important for testicular function in mammals are well represented in the medaka testicular EST collection. CONCLUSIONS/SIGNIFICANCE: Medaka exhibits a considerable similarity in testicular gene expression to mammals. The medaka testicular EST collection we obtained has wide range coverage and will not only consolidate our knowledge on the comparative analysis of known genes' functions in the testis but also provide a rich resource to dissect molecular events and mechanism of spermatogenesis in vivo and in vitro in medaka as an excellent vertebrate model
Modelling Strategies for Predicting the Residual Strength of Impacted Composite Aircraft Fuselages
Aeronautic Certification rules established for the metallic materials are not convenient for the composite structures concerning the resistance against impact. The computerbased design is a new methodology that is thought about to replace the experimental tests. It becomes necessary for numerical methods to be robust and predictive for impact. Three
questions are addressed in this study: (i) can a numerical model be “mechanically intrinsic” to predict damage after impact, (ii) can this model be the same for a lab sample and a large structure, and (iii) can the numerical model be predictive enough to predict the Compression After Impact (CAI)? Three different computational strategies are used and compared: a Cohesive Model (CM), a Continuous Damage Model (CDM) coupling failure modes and
damage, and a Mixed Methodology (MM) using the CDM for delamination initiation and the
CM for cracks propagation. The first attempts to use the Smooth Particle Hydrodynamics
method are presented. Finally, impact on a fuselage is modelled and a numerical two-stage
strategy is developed to predict the CAI
Potent Antioxidant and Genoprotective Effects of Boeravinone G, a Rotenoid Isolated from Boerhaavia diffusa
Background and Aims: Free radicals are implicated in the aetiology of some gastrointestinal disorders such as gastric ulcer, colorectal cancer and inflammatory bowel disease. In the present study we investigated the antioxidant and genoprotective activity of some rotenoids (i.e. boeravinones) isolated from the roots of Boerhaavia diffusa, a plant used in the Ayurvedic medicine for the treatment of diseases affecting the gastrointestinal tract. Methods/Principal Findings: Antioxidant activity has been evaluated using both chemical (Electron Spin Resonance spectroscopy, ESR) and Caco-2 cells-based (TBARS and ROS) assays. DNA damage was evaluated by Comet assay, while pERK 1/2 and phospho-NF-kB p65 levels were estimated by western blot. Boeravinones G, D and H significantly reduced the signal intensity of ESR induced by hydroxyl radicals, suggesting a scavenging activity. Among rotenoids tested, boeravinone G exerted the most potent effect. Boeravinone G inhibited both TBARS and ROS formation induced by Fenton's reagent, increased SOD activity and reduced H 2O 2-induced DNA damage. Finally, boeravinone G reduced the levels of pERK 1 and phospho-NF-kB p65 (but not of pERK 2) increased by Fenton's reagent. Conclusions: It is concluded that boeravinone G exhibits an extraordinary potent antioxidant activity (significant effect in the nanomolar range). The MAP kinase and NF-kB pathways seem to be involved in the antioxidant effect of boeravinone G. Boeravinone G might be considered as lead compound for the development of drugs potentially useful against those pathologies whose aetiology is related to ROS-mediated injuries
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Organizational innovation in the multinational enterprise: internalization theory and business history
This article engages in a methodological experiment by using historical evidence to challenge a common misperception about internalization theory. The theory has often been criticized for maintaining that it assumes a hierarchically organized MNE based on knowledge flowing from the home country. This is not an accurate description of how global firms operate in recent decades, but this article shows it has never been true historically. Using longitudinal data on individual firms from the nineteenth century onwards, it reveals evidence of how entrepreneurs and firms with multinational activity faced with market imperfections changed the design of their headquarters and their organizational structures
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