H Saarikoski | Search PubMed

PubMed2004

Vortex clusters in quantum dots.

We study electronic structures of two-dimensional quantum dots in strong magnetic fields using mean-field density-functional theory and exact diagonalization. Our numerically accurate mean-field solutions show a reconstruction of the uniform-density electron droplet when the magnetic field flux quanta enter one by one the dot in stronger fields. These quanta correspond to repelling vortices forming polygonal clusters inside the dot. We find similar structures in the exact treatment of the problem by constructing a conditional operator for the analysis. We discuss important differences and limitations of the methods used.

Journal Article↗

PubMed1999

Variation in referring newborns to special care in Finland.

We studied the frequency of referring newborns to special care in Finland and its variation between hospitals. Data was obtained from the nationwide Finnish Birth Register for 1991 and 1994. Newborns who during their first week of life had been in special care, in another hospital, in a respirator, or who had received a blood exchange were defined as having been in special care. This applied to 7% of newborns in 1991 and to 8% in 1994. The proportions of newborns in special care varied notably between hospitals of the same level. The differences could be explained by varying patient mixtures and different thresholds for referral to care. The indications for referring newborns into special care, especially in hospitals with high rates of referral, requires scrutiny.

Catchment Area, Health↗