Unusual features of pomoviral RNA movement

This work is partially supported by the Scottish Government’s Rural and Environment Science and Analytical Services (RESAS) DivisionPotato mop-top pomovirus (PMTV) is one of a few viruses that can move systemically in plants in the absence of the capsid protein (CP). Pomoviruses encode the triple gene block genetic module of movement proteins (TGB 1, 2, and 3) and recent research suggests that PMTV RNA is transported either as ribonucleoprotein (RNP) complexes containing TGB1 or encapsidated in virions containing TGB1. Furthermore, there are different requirements for local or systemic (long-distance) movement. Research suggests that nucleolar passage of TGB1 may be important for the long-distance movement of both RNP and virions. Moreover, and uniquely, the long-distance movement of the CP-encoding RNA requires expression of both major and minor CP subunits and is inhibited when only the major CP sub unit is expressed. This paper reviews pomovirus research and presents a current model for RNA movement.Publisher PDFPeer reviewe

Temperature-dependent Fermi surface evolution in heavy fermion CeIrIn5

In Cerium-based heavy electron materials, the 4f electron's magnetic moments bind to the itinerant quasiparticles to form composite heavy quasiparticles at low temperature. The volume of the Fermi surfacein the Brillouin zone incorporates the moments to produce a "large FS" due to the Luttinger theorem. When the 4f electrons are localized free moments, a "small FS" is induced since it contains only broad bands of conduction spd electrons. We have addressed theoretically the evolution of the heavy fermion FS as a function of temperature, using a first principles dynamical mean-field theory (DMFT) approach combined with density functional theory (DFT+DMFT). We focus on the archetypical heavy electrons in CeIrIn5, which is believed to be near a quantum critical point. Upon cooling, both the quantum oscillation frequencies and cyclotron masses show logarithmic scaling behavior (~ ln(T_0/T)) with different characteristic temperatures T_0 = 130 and 50 K, respectively. The resistivity coherence peak observed at T ~ 50 K is the result of the competition between the binding of incoherent 4f electrons to the spd conduction electrons at Fermi level and the formation of coherent 4f electrons.Comment: 5 pages main article,3 figures for the main article, 2 page Supplementary information, 2 figures for the Supplementary information. Supplementary movie 1 and 2 are provided on the webpage(http://www-ph.postech.ac.kr/~win/supple.html

New Results on e+e- Line Emission in U+Ta Collisions

We present new results obtained from a series of follow-up e+e- coincidence measurements in heavy-ion collisions, utilizing an improved experimental set-up at the double-Orange beta-spectrometer of GSI. The collision system U+Ta was reinvestigated in three independent runs at beam energies in the range (6.0-6.4)xA MeV and different target thicknesses, with the objective to reproduce a narrow sum-energy e+e- line at ~635 keV observed previously in this collision system. At improved statistical accuracy, the line could not be found in these new data. For the ''fission'' scenario, an upper limit (1 sigma) on its production probability per collision of 1.3x10^{-8} can be set which has to be compared to the previously reported value of [4.9 +- 0.8 (stat.) +- 1.0 (syst)]x10^{-7}. In the light of the new results, a reanalysis of the old data shows that the continuous part of the spectrum at the line position is significantly higher than previously assumed, thus reducing the production probability of the line by a factor of two and its statistical significance to < 3.4sigma.Comment: 15 pages, standard LaTeX with 3 included PS figures; Submitted to Physics Letters

Mapping Exoplanets

The varied surfaces and atmospheres of planets make them interesting places to live, explore, and study from afar. Unfortunately, the great distance to exoplanets makes it impossible to resolve their disk with current or near-term technology. It is still possible, however, to deduce spatial inhomogeneities in exoplanets provided that different regions are visible at different times---this can be due to rotation, orbital motion, and occultations by a star, planet, or moon. Astronomers have so far constructed maps of thermal emission and albedo for short period giant planets. These maps constrain atmospheric dynamics and cloud patterns in exotic atmospheres. In the future, exo-cartography could yield surface maps of terrestrial planets, hinting at the geophysical and geochemical processes that shape them.Comment: Updated chapter for Handbook of Exoplanets, eds. Deeg & Belmonte. 17 pages, including 6 figures and 4 pages of reference

Alternative Mathematical Technique to Determine LS Spectral Terms

We presented an alternative computational method for determining the permitted LS spectral terms arising from $l^N$ electronic configurations. This method makes the direct calculation of LS terms possible. Using only basic algebra, we derived our theory from LS-coupling scheme and Pauli exclusion principle. As an application, we have performed the most complete set of calculations to date of the spectral terms arising from $l^N$ electronic configurations, and the representative results were shown. As another application on deducing LS-coupling rules, for two equivalent electrons, we deduced the famous Even Rule; for three equivalent electrons, we derived a new simple rule.Comment: Submitted to Phys. Rev.

Mesoscopic phase statistics of diffuse ultrasound in dynamic matter

Temporal fluctuations in the phase of waves transmitted through a dynamic, strongly scattering, mesoscopic sample are investigated using ultrasonic waves, and compared with theoretical predictions based on circular Gaussian statistics. The fundamental role of phase in Diffusing Acoustic Wave Spectroscopy is revealed, and phase statistics are also shown to provide a sensitive and accurate way to probe scatterer motions at both short and long time scales.Comment: 4 pages, 4 figures, submitted to Physical Review Letter

Electron Impact Excitation Cross Sections for Hydrogen-Like Ions

We present cross sections for electron-impact-induced transitions n --> n' in hydrogen-like ions C 5+, Ne 9+, Al 12+, and Ar 17+. The cross sections are computed by Coulomb-Born with exchange and normalization (CBE) method for all transitions with n < n' < 7 and by convergent close-coupling (CCC) method for transitions with n 2s and 1s --> 2p are presented as well. The CCC and CBE cross sections agree to better than 10% with each other and with earlier close-coupling results (available for transition 1 --> 2 only). Analytical expression for n --> n' cross sections and semiempirical formulae are discussed.Comment: RevTeX, 5 pages, 13 PostScript figures, submitted to Phys. Rev.

A theoretical study of the C- 4So_3/2 and 2Do_{3/2,5/2} bound states and C ground configuration: fine and hyperfine structures, isotope shifts and transition probabilities

This work is an ab initio study of the 2p3 4So_3/2, and 2Do_{3/2,5/2} states of C- and 2p2 3P_{0,1,2}, 1D_2, and 1S_0 states of neutral carbon. We use the multi-configuration Hartree-Fock approach, focusing on the accuracy of the wave function itself. We obtain all C- detachment thresholds, including correlation effects to about 0.5%. Isotope shifts and hyperfine structures are calculated. The achieved accuracy of the latter is of the order of 0.1 MHz. Intra-configuration transition probabilities are also estimated.Comment: 15 pages, 2 figures, 12 table

Larkin-Ovchinnikov-Fulde-Ferrell phase in the superconductor (TMTSF)2ClO4: Theory versus experiment

We consider a formation of the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase in a quasi-one-dimensional (Q1D) conductor in a magnetic field, parallel to its conducting chains, where we take into account both the paramagnetic spin-splitting and orbital destructive effects against superconductivity. We show that, due to a relative weakness of the orbital effects in a Q1D case, the LOFF phase appears in (TMTSF)$_2$ClO$_4$ superconductor for real values of its Q1D band parameters. We compare our theoretical calculations with the recent experimental data by Y. Maeno's group [S. Yonezawa et al., Phys. Rev. Lett. \textbf{100}, 117002 (2008)] and show that there is a good qualitative and quantitative agreement between the theory and experimental data.Comment: 4 pages, 1 figur

Quantum-mechanical calculation of Stark widths of Ne VII n=3, Δn=0\Delta n=0 transitions

The Stark widths of the Ne VII 2s3s-2s3p singlet and triplet lines are calculated in the impact approximation using quantum-mechanical Convergent Close-Coupling and Coulomb-Born-Exchange approximations. It is shown that the contribution from inelastic collisions to the line widths exceeds the elastic width contribution by about an order of magnitude. Comparison with the line widths measured in a hot dense plasma of a gas-liner pinch indicates a significant difference which may be naturally explained by non-thermal Doppler effects from persistent implosion velocities or turbulence developed during the pinch implosion. Contributions to the line width from different partial waves and types of interactions are discussed as well.Comment: 8 pages, 3 figures; accepted by Phys. Rev.