Breakdown and asymptotic properties of resampled estimates

In this paper we study the breakdown and asymptotic properties of resampled t-estimates. We find that they retain the finite breakdown point of the exact estimator. We also study their consistency and their order of convergence under nonstandard assumptions on the loss functions

Dispersion phenomena in microchannels: Transition from Taylor-Aris to convection-dominated regime

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.This article addresses the qualitative and quantitative properties of solute transport and dispersion in microchannel of finite-length. As the Peclet number increases a transition from the Taylor-Aris to a new regime referred as convection dominated dispersion occurs, which is controlled by the velocity profile near the stagnation points at the solid walls. The properties characterizing dispersion dominated regime can be used for analytical purposes as a chromatographic-based velocimetry and for determining the eventual occurrence of slip at the solid walls of microchannels

Circadian Features of Neutrophil Biology

Rhythms in immunity manifest in multiple ways, but perhaps most prominently by the recurrent onset of inflammation at specific times of day. These patterns are of importance to understand human disease and are caused, in many instances, by the action of neutrophils, a myeloid leukocyte with striking circadian features. The neutrophil's short life, marked diurnal variations in number, and changes in phenotype while in the circulation, help explain the temporal features of inflammatory disease but also uncover core features of neutrophil physiology. Here, we summarize well-established concepts and introduce recent discoveries in the biology of these cells as they relate to circadian rhythms. We highlight that although the circadian features of neutrophils are better known and relevant to understand disease, they may also influence important aspects of organ function even in the steady-state. Finally, we discuss the possibility of targeting these temporal features of neutrophils for therapeutic benefit

Gravitational instability of solar prominence threads I. Curved magnetic fields without dips

Prominence threads are dense and cold structures lying on curved magnetic fields that can be suspended in the solar atmosphere against gravity. The gravitational stability of threads, in the absence of non-ideal effects, is comprehensively investigated in the present work by means of an elementary but effective model. Based on purely hydrodynamic equations in one spatial dimension and applying line-tying conditions at the footpoints of the magnetic field lines, we derive analytical expressions for the different feasible equilibria and the corresponding frequencies of oscillation. We find that the system allows for stable and unstable equilibrium solutions subject to the initial position of the thread, its density contrast and length, and the total length of the magnetic field lines. The transition between the two types of solutions is produced at specific bifurcation points that have been determined analytically in some particular cases. When the thread is initially at the top of the concave magnetic field, that is at the apex, we find a supercritical pitchfork bifurcation, while for a shifted initial thread position with respect to this point the symmetry is broken and the system is characterised by an S-shaped bifurcation. The plain results presented in this paper shed new light on the behaviour of threads in curved magnetic fields under the presence of gravity and help to interpret more complex numerical magnetohydrodynamics (MHD) simulations about similar structures.Comment: 13 pages, 9 figure

Papel homeostático e inflamatorio de neutrófilos senescentes

Los neutrófilos son los leucocitos más abundantes en la circulación humana y representan la primera barrera de defensa contra microorganismos patógenos. Su número en circulación muestra un comportamiento temporalmente oscilatorio, con una periodicidad circadiana. Son células con una vida corta, en el rango de horas desde que salen de la médula ósea hasta que son eliminadas de la circulación (clearance). En ese lapso de tiempo sufren un proceso conocido como envejecimiento que provoca cambios fenotípicos en varios marcadores de superficie y precede en el tiempo a la fase de clearance. Así, durante el día los neutrófilos muestran un fenotipo esencialmente “envejecido” (también llamado senescente) y durante la noche un fenotipo “fresco”. En este trabajo hemos analizado este proceso de envejecimiento de los neutrófilos en ratones y demostramos que está controlado por el reloj molecular y la señalización de dos receptores de quimioquinas, CXCR2 y CXCR4, que funcionan de manera antagónica. Hemos analizado el proceso transcriptómicamente y demostramos que se trata de un programa transcripcional global que afecta a gran cantidad de rutas bioquímicas y dota de propiedades específicas a los neutrófilos. Para estudiar éstas en detalle hemos generado y caracterizado ratones mutantes específicamente en neutrófilos para los genes que regulan el envejecimiento..

La càtedra Endesa red i el vehicle elètric

Abstract not availabl

Sic1 plays a role in timing and oscillatory behaviour of B-type cyclins

Budding yeast cell cycle oscillates between states of low and high cyclin-dependent kinase activity, driven by association of Cdk1 with B-type (Clb) cyclins. Various Cdk1-Clb complexes are activated and inactivated in a fixed, temporally regulated sequence, inducing the behaviour known as "waves of cyclins". The transition from low to high Clb activity is triggered by degradation of Sic1, the inhibitor of Cdk1-Clb complexes, at the entry to S phase. The G(1) phase is characterized by low Clb activity and high Sic1 levels. High Clb activity and Sic1 proteolysis are found from the beginning of the S phase until the end of mitosis. The mechanism regulating the appearance on schedule of Cdk1-Clb complexes is currently unknown. Here, we analyse oscillations of Clbs, focusing on the role of their inhibitor Sic1. We compare mathematical networks differing in interactions that Sic1 may establish with Cdk1-Clb complexes. Our analysis suggests that the wave-like cyclins pattern derives from the binding of Sic1 to all Clb pairs rather than from Clb degradation. These predictions are experimentally validated, showing that Sic1 indeed interacts and coexists in time with Clbs. Intriguingly, a sic1Delta strain looses cell cycle-regulated periodicity of Clbs, which is observed in the wild type, whether a SIC1-0P strain delays the formation of Clb waves. Our results highlight an additional role for Sic1 in regulating Cdk1-Clb complexes, coordinating their appearance

Revista de Vertebrados de la Estación Biológica de Doñana

Anfibios fósiles del Pleistoceno de Mallorca.Species densities of Reptiles and Amphibiansfon the Iberian PeninsulaEcología alimenticia del Petirrojo (Erithacus rubecula) durante su invernada en encinares del Sur de EspañaEl papel d. la Perdiz roja (Alectoris rufa) en la dieta de los predadores IbéricosComposición de las Comunidades de Passeriformes en dos biotopos de Sierra Morena Occidental.Sobre las Ginetas de la Isla de Ibiza (Genetta genetta isabelae n. ssp.)Peer reviewe