Numerically efficient real space theory of scattering from colloidal crystals.

The production of high-quality colloidal crystals demands precise quantitative characterization of their nanostructures. While small-angle radiation scattering is the technique of choice, a procedure for a comprehensive quantitative modeling of the data is still pending. A novel theory based on the pertinent radial pair distribution which takes into account orientational, positional, stacking disorder and grain effects is developed here. We also show how the scattering length density of the particles can be estimated from the positions of minima in the form factor. The obtained results can be cast as sums of analytical functions over the distribution function and, as such, are suitable for easy (automatic) parallelization. On the experimental side, we report on a strong extinction effect coming from grazing incidence specular reflection that we have been able to model analytically.

Atlas: a java-based tool for managing genotypes.

With the exponential increase in genotyping capability, it is fundamental to check data consistency and improve genotype management. Atlas is a Java-based application for managing genotypes that also provides a series of tools useful in traceability, parentage testing, and identification, as well as pedigree and marker visualization.

Characterization of latex particle arrays by gas adsorption.

Assemblies of colloidal particles are frequently used in novel applications, and this requires nondestructive methods allowing overall characterization of the sample and collection of information about the quality of the arrays. From suspensions of polystyrene, poly[styrene-co-(2-hydroxyethylmethacrylate)], poly[styrene-co-acrylic acid], and poly[styrene-co-methacrylic acid], assemblies of spherical particles were obtained by elimination of the solvent in different ways-evaporation, gravity deposition, and filtration. These latex particle packings were characterized by scanning and transmission electron microscopy and by gas adsorption to determine the efficiency of packing. The surface area, total pore volume, and pore size distributions obtained from the adsorption and desorption data were related to characteristic parameters calculated for cubic close-packed spherical particles.

Unconventional density dependence of the stochastic dynamics in an organic liquid.

The density dependence of the diffusive rotational and center-of-mass dynamics of 2-methyl-pyridine is investigated by means of the concurrent use of quasielastic neutron scattering and molecular dynamics simulations. The dependence of both translation and rotational diffusion coefficients shows a distinctive change of slope with increasing density taking place about rho=0.975 g/cm3. Such a change in the dynamics can be related to observations made in other liquids composed of oblate-spheroidal particles.

Critical behavior of ionic solids.

Phase transitions of lattice models of ionic crystals are studied by computer simulation. The nature of order-disorder transitions on different crystal structures is established and compared with the behavior of related Ising models. It is found that for both, continuous and first order transitions the basic features seem to be similar to those of Ising systems.

[Lepiota bruneoincarnata fatal intoxication]. / Intoxicación fatal por Lepiota bruneoincarnata.

Mushroom poisoning does not occur very often but in autumn the incidence increases. The seriousness of symptoms in some cases justifies the revision of this issue just the event of one family cases occurred recently in our environment. In this paper we are presenting two cases of intoxication by Lepiota bruneoincarnata in two patients of the same family who suffers visceral involvement with a hepatic strike down and death in one of the patients. The rarity, and seriousness of symptoms together with the similarity with intoxication by Amanita phalloides seem very interesting to us to be published.

Intoxicación fatal por Lepiota bruneoincarnata / Lepiota bruneoincarnata fatal intoxication

La intoxicación por setas no suele ser habitual, pero es de elevada incidencia en el periodo otoñal y la gravedad de los síntomas, en algunos casos, justifica la revisión del tema, a propósito de un caso familiar acaecido recientemente en nuestro medio.En este artículo presentamos dos casos de intoxicación por Lepiota bruneoincarnata en dos pacientes de la misma familia, que desarrollaron afectación visceral con alteración de la función hepática, con desenlace fatal en uno de ellos.La rareza, gravedad de los síntomas y su semejanza con las intoxicaciones por Amanita phalloides nos ha parecido interesante para su publicación (AU)

Reentrant miscibility in fluids with spherical interactions.

We have obtained the closed-loop fluid-fluid immiscibility in the phase diagram of a binary mixture with interactions with spherical symmetry. That topology appears when a short-range attractive interaction is considered between unlike pair molecules. We present "exact" results obtained from Monte Carlo simulation on different ensembles and results from the application of a first-order perturbation theory.

Molecular approach to the interpretation of the dielectric relaxation spectrum of a molecular glass former

The frequency-dependent dielectric function of ethanol at temperatures within the normal liquid range is evaluated by means of computer molecular dynamics simulations and compared with recent experimental data. The calculated spectra show a similar structure to those reported from experimental measurements and the temperature dependence of its most prominent bands also follows the experimental estimates. An attempt is also made to assign the most intense bands to specific molecular reorientations.