Romanian Academy

About: Romanian Academy is a archive organization based out in Bucharest, Romania. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 3662 authors who have published 10491 publications receiving 146447 citations. The organization is also known as: Academia Română & Societatea Literară Română.

The three-dimensional velocity structure of the thick disk from spm4 and rave dr2

Abstract: We analyze the three-dimensional kinematics of a sample of ~4400 red clump stars ranging between 5 and 10?kpc from the Galactic center and up to 3 kpc from the Galactic plane. This sample is representative for the metal-rich ([Fe/H] = ?0.6 ? +0.5) thick disk. Absolute proper motions are from the fourth release of the Southern Proper Motion Program and radial velocities from the second release of the Radial Velocity Experiment. The derived kinematical properties of the thick disk include the rotational velocity gradient ?V ?/?z = ?25.2 ? 2.1?km?s?1?kpc?1, velocity dispersions ?km?s?1, and velocity-ellipsoid tilt angle ? Rz = 86 ? 18. Our dynamical estimate of the thin-disk scale length is R thin = 2.0 ? 0.4 kpc and of the thick-disk scale height is z thick = 0.7 ? 0.1 kpc. The observed orbital eccentricity distribution compared with those from four different models of the formation of the thick disk from Sales et?al. favors the gas-rich merger model and the minor merger heating model. Interestingly, when referred to the currently accepted value of the LSR, stars more distant than 0.7 kpc from the Sun show a net average radial velocity of 13 ? 3?km?s?1. This result is seen in previous kinematical studies using other tracers at distances larger than ~1 kpc. We suggest this motion reflects an inward perturbation of the locally defined LSR induced by the spiral density wave.

Yangians and cohomology rings of Laumon spaces

Abstract: Laumon moduli spaces are certain smooth closures of the moduli spaces of maps from the projective line to the flag variety of GL n. We construct the action of the Yangian of sln in the cohomology of Laumon spaces by certain natural correspon- dences. We construct the action of the affine Yangian (two-parametric deformation of the universal enveloping algebra of the universal central extension of sln(s ±1 , t)) in the cohomology of the affine version of Laumon spaces. We compute the matrix coefficients of the generators of the affine Yangian in the fixed point basis of coho- mology. This basis is an affine analog of the Gelfand-Tsetlin basis. The affine analog of the Gelfand-Tsetlin algebra surjects onto the equivariant cohomology rings of the affine Laumon spaces. The cohomology ring of the moduli space Mn,d of torsion free sheaves on the plane, of rank n and second Chern class d, trivialized at infinity, is

Artificial Inoculation—Perspectives in Tailings Phytostabilization

Abstract: Intensive mining and processing activities worldwide resulted in the generation of huge amounts of waste (tailings), generally characterized as toxic, radioactive, and/or hazardous. The exposure po...

Evolution of the radio-X-ray coupling throughout an entire outburst of Aquila X-1

Abstract: The 2009 November outburst of the neutron star X-ray binary Aquila X-1 (Aql X-1) was observed with unprecedented radio coverage and simultaneous pointed X-ray observations, tracing the radio emission around the full X-ray hysteresis loop of the outburst for the first time. We use these data to discuss the disk-jet coupling, finding the radio emission to be consistent with being triggered at state transitions, both from the hard to the soft spectral state and vice versa. Our data appear to confirm previous suggestions of radio quenching in the soft state above a threshold X-ray luminosity of ~10% of the Eddington luminosity. We also present the first detections of Aql X-1 with very long baseline interferometry, showing that any extended emission is relatively diffuse and consistent with steady jets rather than arising from discrete, compact knots. In all cases where multi-frequency data were available, the source radio spectrum is consistent with being flat or slightly inverted, suggesting that the internal shock mechanism that is believed to produce optically thin transient radio ejecta in black hole X-ray binaries is not active in Aql X-1.

Structural determinants at the interface of the ARC2 and leucine-rich repeat domains control the activation of the plant immune receptors Rx1 and Gpa2.

Abstract: Many plant and animal immune receptors have a modular nucleotide-binding-leucine-rich repeat (NB-LRR) architecture in which a nucleotide-binding switch domain, NB-ARC, is tethered to a LRR sensor domain. The cooperation between the switch and sensor domains, which regulates the activation of these proteins, is poorly understood. Here, we report structural determinants governing the interaction between the NB-ARC and LRR in the highly homologous plant immune receptors Gpa2 and Rx1, which recognize the potato cyst nematode Globodera pallida and Potato virus X, respectively. Systematic shuffling of polymorphic sites between Gpa2 and Rx1 showed that a minimal region in the ARC2 and N-terminal repeats of the LRR domain coordinate the activation state of the protein. We identified two closely spaced amino acid residues in this region of the ARC2 (positions 401 and 403) that distinguish between autoactivation and effector-triggered activation. Furthermore, a highly acidic loop region in the ARC2 domain and basic patches in the N-terminal end of the LRR domain were demonstrated to be required for the physical interaction between the ARC2 and LRR. The NB-ARC and LRR domains dissociate upon effector-dependent activation, and the complementary-charged regions are predicted to mediate a fast reassociation, enabling multiple rounds of activation. Finally, we present a mechanistic model showing how the ARC2, NB, and N-terminal half of the LRR form a clamp, which regulates the dissociation and reassociation of the switch and sensor domains in NB-LRR proteins.