ABSTRACT
We present the results of extensive Monte Carlo simulations of intercalated manganese-titanium (Mn-Ti) layered TiS2 crystals. The computational model involves mixtures of Mn and Ti in various percentages placed on a triangular lattice with fixed lattice sites and up to five layers. The range of concentrations of intercalated Mn studied was 5% ⩽ X Mn ⩽ 33% and for Ti, 0% ⩽ X Ti ⩽ 15%, where X A denotes the percentage of the total number of lattice sites occupied by species A. The species are allowed to interact spatially through a screened Coulomb potential and magnetically with external and RKKY field terms. Structurally, the pure Mn systems present as disordered at very low densities and evolve through a 2 × 2 structure (perfect at X Mn = 25%) up to a [Formula: see text] × [Formula: see text] lattice (perfect at X Mn = 33%), with variations of the two 'perfect' lattice structures depending on density. Changes in density for pure Mn systems as well as those intercalated with both Mn and Ti dramatically affects the system's structural and magnetic properties, and the magnetic behavior of various morphological features present in the system are discussed. The RKKY interaction is adjusted based on the intercalant compositions and is very sensitive to structural variations in the intercalant layers. The composition ranges studied here encompass and exceed those that are experimentally accessible, which helps place experimentally relevant densities in perspective.
ABSTRACT
BACKGROUND: The parent questionnaire ELFRA-2 is considered a valid tool for early detection of delayed language development in 2-year-old children. Applicability for children treated with cochlear implants (CI) is to be investigated. METHODS: By means of the ELFRA-2 we documented longitudinally for up to 24 months post implantation language development in 27 children treated before 3 years of age. The critical developmental criteria (related to age) were applied to CI children (related to duration of CI use) and gender-related normative data were taken as a reference. RESULTS: Only two boys were identified as showing a language delay after 2 years of CI use. However, using normative data 11-44% of the children performed below average. Development in girls was faster than in boys. The influence of preoperative hearing experience declined over time. CONCLUSION: The critical developmental criteria of ELFRA-2 have proved to be unreliable for the identification of varying development after CI. Modified and gender-related evaluation is necessary.
