An Overview of the Origin of Galactic Cosmic Rays as Inferred from Observations of Heavy Ion Composition and Spectra

The galactic cosmic rays arriving near Earth, which include both stable and long-lived nuclides from throughout the periodic table, consist of a mix of stellar nucleosynthesis products accelerated by shocks in the interstellar medium (ISM) and fragmentation products made by high-energy collisions during propagation through the ISM. Through the study of the composition and spectra of a variety of elements and isotopes in this diverse sample, models have been developed for the origin, acceleration, and transport of galactic cosmic rays. We present an overview of the current understanding of these topics emphasizing the insights that have been gained through investigations in the charge and energy ranges Z≲30 and E/M≲1 GeV/nuc, and particularly those using data obtained from the Cosmic Ray Isotope Spectrometer on NASA’s Advanced Composition Explorer mission.     

MHD numerical simulations of proto-stellar jets

We will summarize in this paper the effects that the presence of the magnetic field can cause to proto-stellar jet dynamics, structure and emission line properties, and the differences between two- and three-dimensional numerical simulations will be emphasized. This revised version was published online in August 2006 with corrections to the Cover Date.     

Methods for Characterising Microphysical Processes in Plasmas

Advanced spectral and statistical data analysis techniques have greatly contributed to shaping our understanding of microphysical processes in plasmas. We review some of the main techniques that allow for characterising fluctuation phenomena in geospace and in laboratory plasma observations. Special emphasis is given to the commonalities between different disciplines, which have witnessed the development of similar tools, often with differing terminologies. The review is phrased in terms of few important concepts: self-similarity, deviation from self-similarity (i.e. intermittency and coherent structures), wave-turbulence, and anomalous transport.     

Solar activity and human health at middle and low geomagnetic latitudes in Central America

The study of the possible effect of solar variability on living organisms is one of the most controversial issues of present day science. It has been firstly and mainly carried on high latitudes, while at middle and low latitudes this study is rare. In the present review we focused on the work developed at middle and low geomagnetic latitudes of America. At these geomagnetic latitudes the groups consistently dedicated to this issue are mainly two, one in Cuba and the other in Mexico.     

Where does the stone go when we drop it? Development of French schoolchildren’s knowledge of gravity

In this study, we explored children’s knowledge of gravity at different ages (5–6, 7–8, and 9–10 years), by asking the same question (“Where does a stone go when we drop it?”) in three different contexts (on Earth, in a spaceship orbiting the Earth, and on the Moon). We tested the influence of context and children’s age on both the answers and the justifications they provided. We expected that children of all ages would find it easier to make correct predictions in the Earth context than in the other two contexts. We were also interested in the kinds of justification children construct and how these justifications change during ontogenesis. Seventy-two French children were individually interviewed at their school. None of them had received any direct teaching about gravity. Results showed that children found it easier to predict the fall of the stone on Earth than its behaviour in the other two contexts, but that the younger children predicted the fall of the stone on the Moon more accurately than the older children. This unusual developmental effect only occurred for the Moon context. We also found that the categories of justifications changed with age, with a move away from intuitive considerations towards mechanistic ones.     

稀土对硼铝共渗扩散机制的影响

建立了硼原子和铝原子的扩散模型 ,讨论了稀土对硼原子和铝原子扩散机制的影响。分析认为 :硼原子的扩散速度受 Fe2 B前沿硼原子向基体扩散速度的影响 ,也受硼原子通过 Fe2 B晶胞向基体扩散速度的控制 ;铝原子是在硼化物覆盖表面之前渗入的 ,当硼化物完全覆盖表面后 ,阻碍了铝原子的扩散 ,故铝在渗层次表面形成了化合物 ;稀土的渗入增加了空位数 ,使空位复合体的数量增加 ,也就加速了硼原子的扩散速度 ,增加了铝原子的渗入量     

C. C. Petersen and J. C. Brandt,Hubble Vision,Early Adventures with the Hubble Space Telescope

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