Analysis of the Very Inner Milky Way Dark Matter Distribution and Gamma-Ray Signals

We analyze the possibility that the HESS gamma-ray source at the Galactic Center could be explained as the secondary flux produced by annihilation of TeV Dark Matter (TeVDM) particles with locally enhanced density, in a region spatially compatible with the HESS observations themselves. We study the inner 100 pc considering (i) the extrapolation of several density profiles from state-of-the-art N-body + Hydrodynamics simulations of Milky Way-like galaxies, (ii) the DM spike induced by the black hole, and (iii) the DM particles scattering off by bulge stars. We show that in some cases the DM spike may provide the enhancement in the flux required to explain the cut-off in the HESS J1745-290 gamma-ray spectra as TeVDM. In other cases, it may helps to describe the spatial tail reported by HESS II at angular scales < 0.54 degrees towards Sgr A.Comment: 6 pages, 3 figures, 1 table. Accepted for publication in Physical Review D - Rapid Communication

LmaPA2G4, a Homolog of Human Ebp1, Is an Essential Gene and Inhibits Cell Proliferation in L. major

We have identified LmaPA2G4, a homolog of the human proliferation-associated 2G4 protein (also termed Ebp1), in aphosphoproteomic screening. Multiple sequence alignment and cluster analysis revealed that LmaPA2G4 is a non-peptidasemember of the M24 family of metallopeptidases. This pseudoenzyme is structurally related to methionine aminopeptidases. Anull mutant system based on negative selection allowed us to demonstrate that LmaPA2G4 is an essential gene inLeishmaniamajor. Over-expression of LmaPA2G4 did not alter cell morphology or the ability to differentiate into metacyclic and amastigotestages. Interestingly, the over-expression affected cell proliferation and virulence in mouse footpad analysis. LmaPA2G4 binds asynthetic double-stranded RNA polyriboinosinic polyribocytidylic acid [poly(I:C)] as shown in an electrophoretic mobility shiftassay (EMSA). Quantitative proteomics revealed that the over-expression of LmaPA2G4 led to accumulation of factors involved intranslation initiation and elongation. Significantly, we found a strong reduction ofde novoprotein biosynthesis in transgenicparasites using a non-radioactive metabolic labeling assay. In conclusion, LmaPA2G4 is an essential gene and is potentiallyimplicated in fundamental biological mechanisms, such as translation, making it an attractive target for therapeutic intervention.Fil: Norris Mullins, Brianna. University Of Notre Dame-Indiana; Estados UnidosFil: VanderKolk, Kaitlin. University Of Notre Dame-Indiana; Estados UnidosFil: Vacchina, Paola. University Of Notre Dame-Indiana; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Joyce, Michelle V.. University Of Notre Dame-Indiana; Estados UnidosFil: Morales, Miguel A.. University Of Notre Dame-Indiana; Estados Unido

An amplitude-phase (Ermakov-Lewis) approach for the Jackiw-Pi model of bilayer graphene

In the context of bilayer graphene we use the simple gauge model of Jackiw and Pi to construct its numerical solutions in powers of the bias potential V according to a general scheme due to Kravchenko. Next, using this numerical solutions, we develop the Ermakov-Lewis approach for the same model. This leads us to numerical calculations of the Lewis-Riesenfeld phases that could be of forthcoming experimental interest for bilayer graphene. We also present a generalization of the Ioffe-Korsch nonlinear Darboux transformationComment: FTC, 11 pp, 5 figure

On some exceptional cases in the integrability of the three-body problem

We consider the Newtonian planar three--body problem with positive masses $m_1$, $m_2$, $m_3$. We prove that it does not have an additional first integral meromorphic in the complex neighborhood of the parabolic Lagrangian orbit besides three exceptional cases $\sum m_i m_j/(\sum m_k)^2= 1/3$, $2^3/3^3$, $2/3^2$ where the linearized equations are shown to be partially integrable. This result completes the non-integrability analysis of the three-body problem started in our previous papers and based of the Morales-Ramis-Ziglin approach.Comment: 7 page

Thermoelectric power quantum oscillations in the ferromagnet UGe2_2

We present thermoelectric power and resistivity measurements in the ferromagnet UGe$_2$ as a function of temperature and magnetic field. At low temperature, huge quantum oscillations are observed in the thermoelectric power as a function of the magnetic field applied along the $a$ axis. The frequencies of the extreme orbits are determined and an analysis of the cyclotron masses is performed following different theoretical approaches for quantum oscillations detected in the thermoelectric power. They are compared to those obtained by Shubnikov-de Haas experiments on the same crystal and previous de Haas-van Alphen experiments. The agreement of the different probes confirms thermoelectric power as an excellent probe to extract simultaneously both microscopic and macroscopic information on the Fermi-surface properties. Band-structure calculations of UGe$_2$ in the ferromagnetic state are compared to the experiment.Comment: 10 figures, 12 pages, accepted for publication in Phys. Rev.

Optimization of soliton ratchets in inhomogeneous sine-Gordon systems

Unidirectional motion of solitons can take place, although the applied force has zero average in time, when the spatial symmetry is broken by introducing a potential $V(x)$, which consists of periodically repeated cells with each cell containing an asymmetric array of strongly localized inhomogeneities at positions $x_{i}$. A collective coordinate approach shows that the positions, heights and widths of the inhomogeneities (in that order) are the crucial parameters so as to obtain an optimal effective potential $U_{opt}$ that yields a maximal average soliton velocity. $U_{opt}$ essentially exhibits two features: double peaks consisting of a positive and a negative peak, and long flat regions between the double peaks. Such a potential can be obtained by choosing inhomogeneities with opposite signs (e.g., microresistors and microshorts in the case of long Josephson junctions) that are positioned close to each other, while the distance between each peak pair is rather large. These results of the collective variables theory are confirmed by full simulations for the inhomogeneous sine-Gordon system

All-optical attoclock: accessing exahertz dynamics of optical tunnelling through terahertz emission

The debate regarding attosecond dynamics of optical tunneling has so far been focused on time delays associated with electron motion through the potential barrier created by intense ionizing laser fields and the atomic core. Compelling theoretical and experimental arguments have been put forward to advocate the polar opposite views, confirming or refuting the presence of tunnelling time delays. Yet, such delay, whether present or ot, is but a single quantity characterizing the tunnelling wavepacket; the underlying dynamics are richer. Here we propose to complement photo-electron detection with detecting light, focusing on the so-called Brunel adiation -- the near-instantaneous nonlinear optical response triggered by the tunnelling event. Using the combination of single-color and two-color driving fields, we determine not only the ionization delays, but also the re-shaping of the tunnelling wavepacket as it emerges from the classically forbidden region. Our work introduces a new type of attoclock for optical tunnelling, one that is based on measuring light rather than photo-electrons. All-optical detection paves the way to time-resolving multiphoton transitions across bandgaps in solids, on the attosecond time-scale