Melting behavior of large disordered sodium clusters

The melting-like transition in disordered sodium clusters Na_N, with N=92 and 142 is studied by using a first-principles constant-energy molecular dynamics simulation method. Na_142, whose atoms are distributed in two (surface and inner) main shells with different radial distances to the center of mass of the cluster, melts in two steps: the first one, at approx. 130 K, is characterized by a high intrashell mobility of the atoms, and the second, homogeneous melting, at approx. 270 K, involves diffusive motion of all the atoms across the whole cluster volume (both intrashell and intershell displacements are allowed). On the contrary, the melting of Na_92 proceeds gradually over a very wide temperature interval, without any abrupt step visible in the thermal or structural melting indicators. The occurrence of well defined steps in the melting transition is then shown to be related to the existence of a distribution of the atoms in shells. Thereby we propose a necessary condition for a cluster to be considered rigorously amorphouslike (totally disordered), namely that there are no space regions of the cluster where the local value of the atomic density is considerably reduced. Na_92 is the only cluster from the two considered that verifies this condition, so its thermal behavior can be considered as representative of that expected for amorphous clusters. Na_142, on the other hand, has a discernible atomic shell structure and should be considered instead as just partially disordered. The thermal behavior of these two clusters is also compared to that of icosahedral (totally ordered) sodium clusters of the same sizes.Comment: LaTeX file. 7 pages with 12 picture

Variability in non-invasive brain stimulation studies: reasons and results

Non-invasive brain stimulation techniques (NIBS), such as Theta Burst Stimulation (TBS), Paired Associative Stimulation (PAS) and transcranial Direct Current Stimulation (tDCS), are widely used to probe plasticity in the human motor cortex (M1). Although TBS, PAS and tDCS differ in terms of physiological mechanisms responsible for experimentally-induced cortical plasticity, they all share the ability to elicit long-term potentiation (LTP) and depression (LTD) in M1. However, NIBS techniques are all affected by relevant variability in intra- and inter-subject responses. A growing number of factors contributing to NIBS variability have been recently identified and reported. In this review, we have readdressed the issue of variability in human NIBS studies. We have first briefly discussed the physiological mechanisms responsible for TBS, PAS and tDCS-induced cortical plasticity. Then, we have provided statistical measures of intra- and inter-subject variability, as calculated in previous studies. Finally, we have reported in detail known sources of variability by categorizing them into physiological, technical and statistical factors. Improving knowledge about sources of variability could lead to relevant advances in designing new tailored NIBS protocols in physiological and pathological conditions

A note on the combustion of blends of diesel and soya, sunflower and rapeseed vegetable oils in a light boiler

Producción CientíficaThis paper deals with the study of the vegetable oils (VO) used as fuel for heating. The properties of sunflower, rape and soya oils are studied and these are compared with the properties of C-diesel fuel (used for heating domestic purposes in Spain). The mixtures of VO and diesel are studied and characterized and, finally, the results of a series of combustion trials of the mixtures in a conventional heating installation with a mechanical pulverization burner are presented. The results show that viscosity of VO limits the use of blends up to 40% of them, and the oxygen present in their structures contributes to an efficiency gai

Reseñas

L. MARTZ, Poverty and Welfare in Habsburg Spain. The example of Toled

Raúl Hilberg: La destrucción de los judíos europeos, Madrid, Akal, 2005, traducción de C. Pina, 1.455 págs.

Depto. de Historia, Teorías y Geografías PolíticasFac. de Ciencias Políticas y SociologíaTRUEpu

Procesos cognitivos en la intercomprensión.

Sin resume

Un hipertexto de comprensión para textos científicos.

Sin resume

Hamás se hace fuerte actuando como una ONG

Depto. de Historia, Teorías y Geografías PolíticasFac. de Ciencias Políticas y SociologíaTRUEpu

Zeev Sternhell: Les anti-Lumières: du xviiie siècle à la guerre froide, Fayard, Paris, 2006, 590 págs.

Depto. de Historia, Teorías y Geografías PolíticasFac. de Ciencias Políticas y SociologíaTRUEpu

Cancer immunotherapy as a new treatment option

Cancer can coaptate the immune control of the immune system (IS), evade immunity and its destruction. So, could we say openly that immunotherapy is a viable treatment option for patients with advanced cancer? Yes, immunotherapy would give us great advances in the war against cancer. Therefore, the development of a new generation of immune modulators (which have been analyzed in the following article) is necessary. In addition, these will be more effective if we use them in combination, taking advantage of their synergy.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech