BOSQUE, Ignacio, ed. (2006): Diccionario combinatorio práctico del español contemporáneo [Reseña]

[Resumen] Reseña de Bosque, Ignacio, ed. (2006): Diccionario combinatorio práctico del español contemporáneo, Madrid, SM

Finite temperature effects on the antikaon optical potential

By solving the Bethe-Goldstone equation, we have obtained the $\bar{K}$ optical potential from the $\bar{K}N$ effective interaction in nuclear matter at T=0. We have extended the model by incorporating finite temperature effects in order to adapt our calculations to the experimental conditions in heavy-ion collisions. In the rank of densities ($0-2\rho_0$), the finite temperature $\bar{K}$ optical potential shows a smooth behaviour if we compare it to the T=0 outcome. Our model has also been applied to the study of the ratio between $K^+$ and $K^-$ produced at GSI with $T$ around 70 MeV. Our results point at the necessity of introducing an attractive $\bar{K}$ optical potential.Comment: 7 pages, 4 figures. Contribution to the proceedings of Mesons & Light Nuclei '01 (2-6th July, Prague

Effect of modeled reduced gravity conditions on bacterial morphology and physiology

<p>Abstract</p> <p>Background</p> <p>Bacterial phenotypes result from responses to environmental conditions under which these organisms grow; reduced gravity has been demonstrated in many studies as an environmental condition that profoundly influences microorganisms. In this study, we focused on low-shear stress, modeled reduced gravity (MRG) conditions and examined, for <it>Escherichia coli and Staphlyococcus aureus</it>, a suite of bacterial responses (including total protein concentrations, biovolume, membrane potential and membrane integrity) in rich and dilute media and at exponential and stationary phases for growth. The parameters selected have not been studied in <it>E. coli </it>and <it>S. aureus </it>under MRG conditions and provide critical information about bacterial viability and potential for population growth.</p> <p>Results</p> <p>With the exception of <it>S. aureus </it>in dilute Luria Bertani (LB) broth, specific growth rates (based on optical density) of the bacteria were not significantly different between normal gravity (NG) and MRG conditions. However, significantly higher bacterial yields were observed for both bacteria under MRG than NG, irrespective of the medium with the exception of <it>E. coli </it>grown in LB. Also, enumeration of cells after staining with 4',6-diamidino-2-phenylindole showed that significantly higher numbers were achieved under MRG conditions during stationary phase for <it>E. coli </it>and <it>S. aureus </it>grown in M9 and dilute LB, respectively. In addition, with the exception of smaller <it>S. aureus </it>volume under MRG conditions at exponential phase in dilute LB, biovolume and protein concentrations per cell did not significantly differ between MRG and NG treatments. Both <it>E. coli </it>and <it>S. aureus </it>had higher average membrane potential and integrity under MRG than NG conditions; however, these responses varied with growth medium and growth phase.</p> <p>Conclusions</p> <p>Overall, our data provides novel information about <it>E. coli </it>and <it>S. aureus </it>membrane potential and integrity and suggest that bacteria are physiologically more active and a larger percentage are viable under MRG as compared to NG conditions. In addition, these results demonstrate that bacterial physiological responses to MRG conditions vary with growth medium and growth phase demonstrating that nutrient resources are a modulator of response.</p

Boulder Capture System Design Options for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

This paper presents a boulder acquisition and asteroid surface interaction electromechanical concept developed for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger Near Earth Asteroid (NEA). It details the down select process and ranking of potential boulder capture methods, the evolution of a simple yet elegant articulating spaceframe, and ongoing risk reduction and concept refinement efforts. The capture system configuration leverages the spaceframe, heritage manipulators, and a new microspine technology to enable the ARRM boulder capture. While at the NEA it enables attenuation of terminal descent velocity, ascent to escape velocity, boulder collection and restraint. After departure from the NEA it enables, robotic inspection, sample caching, and crew Extra Vehicular Activities (EVA)

High energy scattering in 2+1 QCD

High energy scattering in 2+1 QCD is studied using the recent approach of Verlinde and Verlinde. We calculate the color singlet part of the quark-quark scattering exactly within this approach, and discuss some physical implication of this result. We also demonstrate, by two independent methods, that reggeization fails for the color singlet channel. We briefly comment on the problem in 3+1 QCD.Comment: 20 pages, references adde

Irreversible and reversible modes of operation of deterministic ratchets

We discuss a problem of optimization of the energetic efficiency of a simple rocked ratchet. We concentrate on a low-temperature case in which the particle's motion in a ratchet potential is deterministic. We show that the energetic efficiency of a ratchet working adiabatically is bounded from above by a value depending on the form of ratchet potential. The ratchets with strongly asymmetric potentials can achieve ideal efficiency of unity without approaching reversibility. On the other hand we show that for any form of the ratchet potential a set of time-protocols of the outer force exist under which the operation is reversible and the ideal value of efficiency is also achieved. The mode of operation of the ratchet is still quasistatic but not adiabatic. The high values of efficiency can be preserved even under elevated temperatures

NLO-QCD Corrections to Dilepton Production in the Randall-Sundrum Model

The dilepton production process at hadron colliders in the Randall-Sundrum (RS) model is studied at next-to-leading order in QCD. The NLO-QCD corrections have been computed for the virtual graviton exchange process in the RS model, in addition to the usual gamma, Z-mediated processes of standard Drell-Yan. K-factors for the cross-sections at the LHC and Tevatron for differential in the invariant mass, Q, and the rapidity, Y, of the lepton pair are presented. We find the K-factors are large over substantial regions of the phase space.Comment: 24 pages, 12 figure

QCD corrections to the electric dipole moment of the neutron in the MSSM

We consider the QCD corrections to the electric dipole moment of the neutron in the Minimal Supersymmetric Standard Model. We provide a master formula for the Wilson coefficients at the low energy scale including for the first time the mixing between the electric and chromoelectric operators and correcting widely used previous LO estimates. We show that, because of the mixing between the electric and chromoelectric operators, the neutralino contribution is always strongly suppressed. We find that, in general, the effect of the QCD corrections is to reduce the amount of CP violation generated at the high scale. We discuss the perturbative uncertainties of the LO computation, which are particularly large for the gluino-mediated contribution. This motivates our Next-to-Leading order analysis. We compute for the first time the order alpha_s corrections to the Wilson coefficients for the gluino contributions, and recompute the two-loop anomalous dimension for the dipole operators. We show that the large LO uncertainty disappears once NLO corrections are taken into account.Comment: 23 pages, 5 figures, added references, corrected typo