Multiple-locus heterozygosity, physiology and growth at two different stages in the life cycle of the Chilean oyster Ostrea chilensis

A random sample of 150 individuals of a laboratory-produced cohort of Ostrea chilensis Philippi, 1845 was taken at 10 and 36 mo of age to estimate physiological variables and individual heterozygosity using 4 loci (Lap, Pgi, Pgm and Ca). Juveniles of 10 mo of age showed a mean D value of 0.134 (p > 0.05) and a positive correlation between oyster size and multiple-locus heterozygosity (MLH) (p 0.05), oxygen consumption rate (p < 0.05) and MLH was found. The K2 value (standardized net growth efficiency) was positively correlated (p < 0.05) with MLH. At 36 mo a heterozygote deficiency was present with a mean value D = -0.431 (p < 0.05). No relationship between standard dry weight and MLH and also a negative correlation between the scope for growth and MLH were found. The oxygen consumption and excretion rates also showed an increase in large size individuals. The slopes for filtration and excretion rates against MLH were negative and not statistically significant. However, ingestion and absorption rates showed significant (p < 0.05) decrease with an increase in heterozygosity. The results seem to indicate that within sexually immature individuals of O. chilensis, a positive correlation between growth rate and MLH can be found, while in adults the higher energy allocation for reproduction precludes the detection of this relationship

Fast inactivation in Shaker K+ channels. Properties of ionic and gating currents.

Fast inactivating Shaker H4 potassium channels and nonconducting pore mutant Shaker H4 W434F channels have been used to correlate the installation and recovery of the fast inactivation of ionic current with changes in the kinetics of gating current known as "charge immobilization" (Armstrong, C.M., and F. Bezanilla. 1977. J. Gen. Physiol. 70:567-590.). Shaker H4 W434F gating currents are very similar to those of the conducting clone recorded in potassium-free solutions. This mutant channel allows the recording of the total gating charge return, even when returning from potentials that would largely inactivate conducting channels. As the depolarizing potential increased, the OFF gating currents decay phase at -90 mV return potential changed from a single fast component to at least two components, the slower requiring approximately 200 ms for a full charge return. The charge immobilization onset and the ionic current decay have an identical time course. The recoveries of gating current (Shaker H4 W434F) and ionic current (Shaker H4) in 2 mM external potassium have at least two components. Both recoveries are similar at -120 and -90 mV. In contrast, at higher potentials (-70 and -50 mV), the gating charge recovers significantly more slowly than the ionic current. A model with a single inactivated state cannot account for all our data, which strongly support the existence of "parallel" inactivated states. In this model, a fraction of the charge can be recovered upon repolarization while the channel pore is occupied by the NH2-terminus region

Fast nucleon emission as a probe of the isospin momentum dependence

In this article we investigate the structure of the non-local part of the symmetry term, that leads to a splitting of the effective masses of protons and neutrons in asymmetric matter. Based on microscopic transport simulations we suggest some rather sensitive observables in collisions of neutron-rich (unstable) ions at intermediate ($RIA$) energies. In particular we focus the attention on pre-equilibrium nucleon emissions. We discuss interesting correlations between the N/Z content of the fast emitted particles and their rapidity or transverse momentum, that show a nice dependence on the prescription used for the effective mass splitting.Comment: 5 pages, 6 figures, revtex

Estudio de existencia de soluciones por elementos finitos de un problema del tipo de capa límite

Se estudia la existencia de soluciones a las ecuaciones algebraicas asociadas a la discretización de un problema modelo similar a las ecuaciones de capa límite. El problema modelo retiene la forma de las no linealidades de la capa limite pero ignora la ecuación de continuidad. De este análisis se siguen criterios que permiten determinar la influencia de parámetros como viscosidad, norma de la velocidad, e incremento en la dirección de avance sobre la existencia de las soluciones algebraicas. Además se estudia la convergencia de la sucesión de soluciones algebraicas a la solución del sistema de ecuaciones ordinarias producto del modelo de elementos finitos de la ecuación parcial en estudio. The existence of solutions to the algebraic equations associate to the finite element approximation of a model problem similar to the boundary layer equations are considered. The model problem retains the form of the nonlinearities present in BLE, but ignores the Continuity Equation. Severa1 criteria which allow to determine the influence of parameters such as viscocity, norm of the velocity or discretizacion step in the streamline direction, on the existence of solutions are studied. The convergence of the sequence of algebraic solutions to the solutions of the ordinary differential equations generated by the FEM model are studied also.Peer Reviewe

Estudio de existencia de soluciones por elementos finitos de un problema del tipo de capa límite

Se estudia la existencia de soluciones a las ecuaciones algebraicas asociadas a la discretización de un problema modelo similar a las ecuaciones de capa límite. El problema modelo retiene la forma de las no linealidades de la capa limite pero ignora la ecuación de continuidad. De este análisis se siguen criterios que permiten determinar la influencia de parámetros como viscosidad, norma de la velocidad, e incremento en la dirección de avance sobre la existencia de las soluciones algebraicas. Además se estudia la convergencia de la sucesión de soluciones algebraicas a la solución del sistema de ecuaciones ordinarias producto del modelo de elementos finitos de la ecuación parcial en estudio. The existence of solutions to the algebraic equations associate to the finite element approximation of a model problem similar to the boundary layer equations are considered. The model problem retains the form of the nonlinearities present in BLE, but ignores the Continuity Equation. Severa1 criteria which allow to determine the influence of parameters such as viscocity, norm of the velocity or discretizacion step in the streamline direction, on the existence of solutions are studied. The convergence of the sequence of algebraic solutions to the solutions of the ordinary differential equations generated by the FEM model are studied also.Peer Reviewe

Evershed clouds as precursors of moving magnetic features around sunspots

The relation between the Evershed flow and moving magnetic features (MMFs) is studied using high-cadence, simultaneous spectropolarimetric measurements of a sunspot in visible (630.2 nm) and near-infrared (1565 nm) lines. Doppler velocities, magnetograms, and total linear polarization maps are calculated from the observed Stokes profiles. We follow the temporal evolution of two Evershed clouds that move radially outward along the same penumbral filament. Eventually, the clouds cross the visible border of the spot and enter the moat region, where they become MMFs. The flux patch farther from the sunspot has the same polarity of the spot, while the MMF closer to it has opposite polarity and exhibits abnormal circular polarization profiles. Our results provide strong evidence that at least some MMFs are the continuation of the penumbral Evershed flow into the moat. This, in turn, suggests that MMFs are magnetically connected to sunspots.Comment: To appear in ApJ Letters, Vol 649, 2006 September 20 issu

Some aspects of the energy cost linked to the IAQ. Impact of free-cooling and heat recovery in office buildings.

CLIMA 2000 (.1997.BRUSELAS)Increasing air exchange rate to improve IAQ may increase energy consumption, but this increase may be compensated for by strategies such as free cooling and heat recovery. The frame of the proposed paper is the examination of the potential at a regional level (the Iberian peninsula) of the different strategies mentioned above in typical office buildings. Based on a set of reference building morphologies, studies are conducted to evaluate the impact of increasing air ventilation rates for different orientations, quality of the envelope (opaque walls and glazing), operating schedules and indoor set-point temperatures. Then, the impact of the increased air ventilation rates is corrected by introducing the effect of free-cooling, air-to-air heat recovery devices of different types and finally, the combined effect of both energy savings strategies. The research provides Maps allowing: 1. To identify zones when heating or cooling regimes are dominant, in terms of both, peak load conditions and energy requirements. 2. To compare the expected performance of the two energy saving strategies at a certain locality. 3. To compare the potential benefit of applying a given strategy at different localities. 4. To indicate regions of recommendable application of the strategies and the expected energy savings achievable