The role of spatial and temporal radiation deposition in inertial fusion chambers: the case of HiPER¿

The first wall armour for the reactor chamber of HiPER will have to face short energy pulses of 5 to 20 MJ mostly in the form of x-rays and charged particles at a repetition rate of 5–10 Hz. Armour material and chamber dimensions have to be chosen to avoid/minimize damage to the chamber, ensuring the proper functioning of the facility during its planned lifetime. The maximum energy fluence that the armour can withstand without risk of failure, is determined by temporal and spatial deposition of the radiation energy inside the material. In this paper, simulations on the thermal effect of the radiation–armour interaction are carried out with an increasing definition of the temporal and spatial deposition of energy to prove their influence on the final results. These calculations will lead us to present the first values of the thermo-mechanical behaviour of the tungsten armour designed for the HiPER project under a shock ignition target of 48 MJ. The results will show that only the crossing of the plasticity limit in the first few micrometres might be a threat after thousands of shots for the survivability of the armour

Evaluating Response Shift in Statistical Mediation Analysis

Researchers and prevention scientists often develop interventions to target intermediate variables (known as mediators) that are thought to be related to an outcome. When researchers target a mediating construct measured by self-report, the meaning of the self-report measure could change from pretest to posttest for the individuals who received the intervention—which is a phenomenon referred to as response shift. As a result, any observed changes on the mediator measure across groups or across time might reflect a combination of true change on the construct and response shift. Although previous studies have focused on identifying the source and type of response shift in measures after an intervention, there has been limited research on how using sum scores in the presence of response shift affects the estimation of mediated effects via statistical mediation analysis, which is critical for explaining how the intervention worked. In this article, we focus on recalibration response shift, which is a change in internal standards of measurement and affects how respondents interpret the response scale. We provide background on the theory of response shift and the methodology used to detect response shift (i.e., tests of measurement invariance). In addition, we used simulated data sets to provide an illustration of how recalibration in the mediator can bias estimates of the mediated effect and affect Type I error and power

Mercury-DPM: Fast particle simulations in complex geometries

Mercury-DPM is a code for performing discrete particle simulations. That is to say, it simulates the motion of particles, or atoms, by applying forces and torques that stem either from external body forces, (e.g. gravity, magnetic fields, etc…) or from particle interactions. For granular particles, these are typically contact forces (elastic, viscous, frictional, plastic, cohesive), while for molecular simulations, forces typically stem from interaction potentials (e.g. Lennard-Jones). Often the method used in these packages is referred to as the discrete element method (DEM), which was originally designed for geotechnical applications. However, as Mercury-DPM is designed for simulating particles with emphasis on contact models, optimized contact detection for highly different particle sizes, and in-code coarse graining (in contrast to post-processing), we prefer the more general name discrete particle simulation. The code was originally developed for granular chute flows, and has since been extended to many other granular applications, including the geophysical modeling of cinder cone creation. Despite its granular heritage it is designed in a flexible way so it can be adapted to include other features such as long-range interactions and non-spherical particles, etc

Semiquantitative theory of electronic Raman scattering from medium-size quantum dots

A consistent semiquantitative theoretical analysis of electronic Raman scattering from many-electron quantum dots under resonance excitation conditions has been performed. The theory is based on random-phase-approximation-like wave functions, with the Coulomb interactions treated exactly, and hole valence-band mixing accounted for within the Kohn-Luttinger Hamiltonian framework. The widths of intermediate and final states in the scattering process, although treated phenomenologically, play a significant role in the calculations, particularly for well above band gap excitation. The calculated polarized and unpolarized Raman spectra reveal a great complexity of features and details when the incident light energy is swept from below, through, and above the quantum dot band gap. Incoming and outgoing resonances dramatically modify the Raman intensities of the single particle, charge density, and spin density excitations. The theoretical results are presented in detail and discussed with regard to experimental observations.Comment: Submitted to Phys. Rev.

Indication Of Unusual Pentagonal Structures In Atomic-size Cu Namwires

A study of the structural and quantum conductance properties of atomic-size copper nanowires generated by mechanical stretching was presented. The time-resolved electron microscopy observations and molecular dynamics simulations were used to derive the atomistic evolution. The quantum transport behavior was analyzed by means of conductance measurements and theoretical calculations. The formation of an unusual and highly pentagonal Cu nanowires with a diameter of ∼0.45 nm and ∼4.5 conductance quanta was also shown.93121261031-126103-4Agraït, N., Yeyati, A.L., Van Ruitenbeek, J.M., (2003) Phys. Rep., 377, p. 81Gulseren, O., Ercolessi, F., Tosatti, E., (1998) Phys. Rev. Lett., 80, p. 3775Kondo, Y., Takayanagi, K., (2000) Science, 289, p. 606Oshima, Y., Onga, A., Takayanagi, K., (2003) Phys. Rev. Lett., 91, p. 205503Ohnishi, H., Kondo, Y., Takayanagi, K., (1998) Nature (London), 395, p. 780Yanson, A.I., (1998) Nature (London), 395, p. 783Rodrigues, V., Fuhrer, T., Ugarte, D., (2000) Phys. Rev. Lett., 85, p. 4124Rego, L.G.C., Rocha, A.R., Rodrigues, V., Ugarte, D., (2003) Phys. Rev. B, 67, p. 045412Rodrigues, V., (2002) Phys. Rev. B, 65, p. 153402Krans, J.M., (1995) Nature (London), 375, p. 767Kondo, Y., Takayanagi, K., (1997) Phys. Rev. Lett., 79, p. 3455Rodrigues, V., Ugarte, D., (2003) Nanowires and Nanobelts, 1, p. 177. , edited by Z. L. Wang Kluwer, DordrechtRodrigues, V., Bettini, J., Silva, P.C., Ugarte, D., (2003) Phys. Rev. Lett., 91, p. 096801Marks, L.D., (1994) Rep. Prog. Phys., 57, p. 603Urban, J., (1998) Cryst. Res. Technol., 33, p. 1009Lisiecki, I., (2000) Phys. Rev. B, 61, p. 4968Emberly, E.G., Kirczenow, G., (1998) Phys. Rev. B, 58, p. 10911(1999) Phys. Rev. B, 60, p. 6028Reinhard, D., (1997) Phys. Rev. Lett., 79, p. 1459Sen, P., (2002) Phys. Rev. B, 65, p. 235433Cleri, F., Rosato, V., (1993) Phys. Rev. B, 48, p. 22Tomànek, D., Aligia, A.A., Balseiro, C.A., (1985) Phys. Rev. B, 32, p. 5051Coura, P.Z., (2004) Nano Lett., 4, p. 1187EPAPS Document No. E-PRLTAO-93-010436, E-PRLTAO-93-010436. , http://www.aip.org/pubservs/epaps.html)orfromftp.aip.orginthedirectory/ epaps, Figure 4 snapshot of a Cu nanowire being elongated along the [110] axis. A direct link to this document may be found in the online article's HTML reference section. The document may also be reached via the EPAPS homepage See the EPAPS homepage for more informatio

Constraining neutrino oscillation parameters with current solar and atmospheric data

We analyze the impact of recent solar, atmospheric and reactor data in the determination of the neutrino oscillation parameters, taking into account that both the solar nu_e and the atmospheric nu_mu may convert to a mixture of active and sterile neutrinos. We use the most recent global solar neutrino data, including the 1496-day Super-K neutrino data sample, and we investigate in detail the impact of the SNO neutral current, spectral and day/night data by performing also an analysis using only the charged current rate from SNO. The implications of the first 145.1 days of KamLAND data on the determination of the solar neutrino parameters are also discussed in detail. We confirm the clear preference of solar+reactor data for the pure active LMA-MSW solution of the solar neutrino problem, and obtain that the LOW, VAC, SMA and Just-So^2 solutions are disfavored with a Delta_chi^2 = 22, 22, 36, 44, respectively. Furthermore, we find that the global solar data constrains the admixture of a sterile neutrino to be less than 43% at 99% CL. By performing an improved fit of the atmospheric data, we also update the corresponding regions of oscillation parameters. We find that the recent atmospheric Super-K (1489-day) and MACRO data have a strong impact on constraining a sterile component in atmospheric oscillations: if the nu_mu is restricted to the atmospheric mass states only a sterile admixture of 16% is allowed at 99% CL, while a bound of 35% is obtained in the unconstrained case. Pure sterile oscillations are disfavored with a Delta_chi^2 = 34.6 compared to the pure active case.Comment: 28 pages, LaTeX file using RevTEX4, 12 figures and 3 tables included. Improved version including the new KamLAND dat

Updated guidelines for gene nomenclature in wheat

The last decade has seen a proliferation in genomic resources for wheat, including reference- and pan-genome assemblies with gene annotations, which provide new opportunities to detect, characterise, and describe genes that influence traits of interest. The expansion of genetic information has supported growth of the wheat research community and catalysed strong interest in the genes that control agronomically important traits, such as yield, pathogen resistance, grain quality, and abiotic stress tolerance. To accommodate these developments, we present an updated set of guidelines for gene nomenclature in wheat. These guidelines can be used to describe loci identified based on morphological or phenotypic features or to name genes based on sequence information, such as similarity to genes characterised in other species or the biochemical properties of the encoded protein. The updated guidelines provide a flexible system that is not overly prescriptive but provides structure and a common framework for naming genes in wheat, which may be extended to related cereal species. We propose these guidelines be used henceforth by the wheat research community to facilitate integration of data from independent studies and allow broader and more efficient use of text and data mining approaches, which will ultimately help further accelerate wheat research and breeding.EEA PergaminoFil: Boden, S. A. University of Adelaide. Waite Research Institute. School of Agriculture, Food and Wine; AustraliaFil: McIntosh, R .A. University of Sydney. School of Life and Environmental Sciences. Plant Breeding Institute; AustraliaFil: Uauy, C. Norwich Research Park. John Innes Centre; Reino UnidoFil: Krattinger, S. G. King Abdullah University of Science and Technology. Biological and Environmental Science and Engineering Division. Plant Science Program; Arabia SauditaFil: Krattinger, S. G. The Wheat Initiative; AlemaniaFil: Dubcovsky, J. University of California. Department of Plant Science; Estados UnidosFil: Dubcovsky, J. The Wheat Initiative; AlemaniaFil: Rogers, W.J. Universidad Nacional del Centro de La Provincia de Buenos Aires. Facultad de Agronomía (CIISAS, CIC-BIOLAB AZUL, CONICET-INBIOTEC, CRESCA). Departamento de Biología Aplicada; ArgentinaFil: Rogers, W.J. The Wheat Initiative; AlemaniaFIL: Xia, X. C. Chinese Academy of Agricultural Sciences. National Wheat Improvement Centre. Institute of Crop Science; ChinaFil: Badaeva, E. D. Russian Academy of Sciences. N.I. Vavilov Institute of General Genetics; RusiaFil: Bentley, A. R. International Maize and Wheat Improvement Center (CIMMYT); MéxicoFil: Bentley, A. R. The Wheat Initiative; AlemaniaFil: Brown-Guedira, G. North Carolina State University. USDA-ARS Plant Science Research; Estados UnidosFil: Brown-Guedira, G. The Wheat Initiative; AlemaniaFil: González, Fernanda G. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Sección Ecofisiología; ArgentinaFil: González, Fernanda G. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires (CITNOBA, CONICET-UNNOBA-UNSADA); ArgentinaFil: González, Fernanda G. The Wheat Initiative; AlemaniaFil: Zhang, Y. Fudan University. School of Life Sciences. Institute of Plant Biology. Collaborative Innovation Center of Genetics and Development. State Key Laboratory of Genetic Engineering; Chin