On the Critical Temperature of Non-Periodic Ising Models on Hexagonal Lattices

The critical temperature of layered Ising models on triangular and honeycomb lattices are calculated in simple, explicit form for arbitrary distribution of the couplings.Comment: to appear in Z. Phys. B., 8 pages plain TEX, 1 figure available upon reques

Phase diagram of an Ising model with long-range frustrating interactions: a theoretical analysis

We present a theoretical study of the phase diagram of a frustrated Ising model with nearest-neighbor ferromagnetic interactions and long-range (Coulombic) antiferromagnetic interactions. For nonzero frustration, long-range ferromagnetic order is forbidden, and the ground-state of the system consists of phases characterized by periodically modulated structures. At finite temperatures, the phase diagram is calculated within the mean-field approximation. Below the transition line that separates the disordered and the ordered phases, the frustration-temperature phase diagram displays an infinite number of ``flowers'', each flower being made by an infinite number of modulated phases generated by structure combination branching processes. The specificities introduced by the long-range nature of the frustrating interaction and the limitation of the mean-field approach are finally discussed.Comment: 32 pages, 7 figure

Genome-wide meta-analyses reveal novel loci for verbal short-term memory and learning

Understanding the genomic basis of memory processes may help in combating neurodegenerative disorders. Hence, we examined the associations of common genetic variants with verbal short-term memory and verbal learning in adults without dementia or stroke (N = 53,637). We identified novel loci in the intronic region of CDH18, and at 13q21 and 3p21.1, as well as an expected signal in the APOE/APOC1/TOMM40 region. These results replicated in an independent sample. Functional and bioinformatic analyses supported many of these loci and further implicated POC1. We showed that polygenic score for verbal learning associated with brain activation in right parieto-occipital region during working memory task. Finally, we showed genetic correlations of these memory traits with several neurocognitive and health outcomes. Our findings suggest a role of several genomic loci in verbal memory processes

NUCLEAR POLARIZATION MEASUREMENTS OF HYDROGEN ATOMS FROM STORAGE CELLS

No abstract availabl

Foam extrusion behavior and correlation between foam morphology and foam properties of externally plasticized cellulose acetate using inert gases

Today, polystyrene (PS) and polypropylene (PP) are the standard polymers for producing extruded foam sheets for packaging. Basically, these polymers are based on non-renewable resources and are non-biodegradable. Additionally, alkanes (e.g. butane) are widely used for the production of extruded PS foam sheets. In comparison to other physical blowing agents (PBA) such as inert gases, alkanes have a high global warming potential (GWP). Both, the polymers and the alkanes used do not fulfill the requirements of sustainable packaging products, which are, especially in the food packaging sector, more important than ever. Cellulose esters such as cellulose acetate (CA) are a promising class of bio-based polymers for producing sustainable foam sheets for thermoformed packaging trays. This contribution presents recent results of foam extrusion using externally plasticized CA and two types of inert gases, namely CO2 and N2, as eco-friendly blowing agents. The foam extrusion behavior, physical foam properties such as foam density, and foam morphologies were investigated