25 research outputs found

    The 'granite encapsulation' route to the safe disposal of Pu and other actinide

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    Waste actinides, including plutonium, present a long-term management problem and a serious security issue. Immobilisation in mineral or ceramic waste forms for interim storage is a widely proposed first step. The safest, most secure geological disposal for Pu is in very deep boreholes and we propose that the key step to combination of these immobilisation and disposal concepts is encapsulation of the waste form in cylinders of recrystallized granite. We discuss the underpinning science, focusing on experimental work, and consider implementation. Finally, we present and discuss analyses of zircon, UO2 and Ce-doped cubic zirconia from high pressure and temperature experiments in granitic melts that demonstrate the viability of this solution and that actinides can be isolated from the environment for millions, maybe hundreds of millions, of years

    Origin and ion charge state evolution of solar wind transients during 4 - 7 August 2011

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    This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 647214). The computational work for this article was carried out on the joint STFC and SFC (SRIF) funded clusters at the University of St Andrews (Scotland, UK). The work is partially supported by RFBR grants 17-02-00787, 14-02-00945 and the P7 Program of the Russian Academy of Sciences.We present a study of the complex event consisting of several solar wind transients detected by the Advanced Composition Explorer (ACE) on 4 - 7 August 2011, which caused a geomagnetic storm with Dst=-110 nT. The supposed coronal sources, three flares and coronal mass ejections (CMEs), occurred on 2 - 4 August 2011 in active region (AR) 11261. To investigate the solar origin and formation of these transients, we study the kinematic and thermodynamic properties of the expanding coronal structures using the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) EUV images and differential emission measure (DEM) diagnostics. The Helioseismic and Magnetic Imager (HMI) magnetic field maps were used as the input data for the 3D magnetohydrodynamic (MHD) model to describe the flux rope ejection (Pagano, Mackay, and Poedts, 2013b). We characterize the early phase of the flux rope ejection in the corona, where the usual three-component CME structure formed. The fluxrope was ejected with a speed of about 200 km s-1 to the height of 0.25 R⊙. The kinematics of the modeled CME front agrees well with the Solar Terrestrial Relations Observatory (STEREO) EUV measurements. Using the results of the plasma diagnostics and MHD modeling, we calculate the ion charge ratios of carbon and oxygen as well as the mean charge state of iron ions of the 2 August 2011 CME, taking into account the processes of heating, cooling, expansion, ionization, and recombination of the moving plasma in the corona up to the frozen-in region. We estimate a probable heating rate of the CME plasma in the low corona by matching the calculated ion composition parameters of the CME with those measured in situ for the solar wind transients. We also consider the similarities and discrepancies between the results of the MHD simulation and the observations.PostprintPeer reviewe

    Space as a Tool for Astrobiology: Review and Recommendations for Experimentations in Earth Orbit and Beyond

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    The Cancer Genome Atlas Comprehensive Molecular Characterization of Renal Cell Carcinoma

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    Renal cell carcinoma(RCC) is not a single disease, but several histologically defined cancers with different genetic drivers, clinical courses, and therapeutic responses. The current study evaluated 843 RCC from the three major histologic subtypes, including 488 clear cell RCC, 274 papillary RCC, and 81 chromophobe RCC. Comprehensive genomic and phenotypic analysis of the RCC subtypes reveals distinctive features of each subtype that provide the foundation for the development of subtype-specific therapeutic and management strategies for patients affected with these cancers. Somatic alteration of BAP1, PBRM1, and PTEN and altered metabolic pathways correlated with subtype-specific decreased survival, while CDKN2A alteration, increased DNA hypermethylation, and increases in the immune-related Th2 gene expression signature correlated with decreased survival within all major histologic subtypes. CIMP-RCC demonstrated an increased immune signature, and a uniform and distinct metabolic expression pattern identified a subset of metabolically divergent (MD) ChRCC that associated with extremely poor survival

    Trajectories of suicide ideation and nonsuicidal self-injury among adolescents in mainland China:Peer predictors, joint development, and risk for suicide attempts

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    Objective: This study expanded knowledge about the development of suicide ideation and nonsuicidal self-injury (NSSI) among adolescents by investigating (a) peer experiences as predictors of trajectories of suicide ideation and NSSI, (b) the joint development of suicide ideation and NSSI, and (c) the risk for suicide attempts (SA) across joint trajectories of suicide ideation and NSSI. Method: At baseline, 565 tenth-grade Chinese adolescents (48.3% males) reported depressive symptoms and friend support. Moreover, peer victimization and friendships were assessed using a sociometric procedure. After baseline, participants completed measures of suicide ideation, NSSI, and SA every 3 months for 2 years. Results: Three similar trajectories of suicide ideation and NSSI were identified. After accounting for depressive symptoms, peer victimization differentiated adolescents in the high trajectory of suicide ideation and NSSI from those in the low and moderate trajectories of suicide ideation and NSSI, respectively. Friend support and friendlessness distinguished between the high and low and the moderate and low NSSI trajectories, respectively. Joint trajectory models revealed a strong overlap between the course of suicide ideation and NSSI: Adolescents in the chronically high suicide ideation trajectory were at the highest risk to follow a chronically high NSSI trajectory and vice versa. Finally, adolescents in the joint chronically high trajectory were approximately 5 times more likely to report SA than were their peers, above and beyond prior SA. Conclusions: Findings highlight the role of negative peer experiences as risk factors for NSSI and suicide ideation, which, in turn, can potentially increase risk for SA
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