Symmetric couplings among aggregates of n chromophores increase the transfer rate of excitons by a factor n(2), a quantum-mechanical phenomenon called 'supertransfer'. In this work, we demonstrate how supertransfer effects induced by geometrical symmetries can enhance the exciton diffusion length by a factor n along cylindrically symmetric structures, consisting of arrays of rings of chromophor...

There are important physiological and pathological cardiovascular consequences related to endothelial biomechanical properties. The endothelium, however, is not unique in responding to external forces; virtually all cells accommodate or respond to the mechanical environment.

We consider a phi4 theory with a position-dependent distance from the critical point. One realization of this model is a classical ferromagnet subject to nonuniform mechanical stress. We find a sharp phase transition where the envelope of the local magnetization vanishes uniformly. The first-order transition in a quantum ferromagnet also remains sharp. The universal mechanism leading to a tricr...

We examine the relationship between two different types of ranked data, frequencies and magnitudes. We consider data that can be sorted out either way, through numbers of occurrences or size of the measures, as it is the case, say, of moon craters, earthquakes, billionaires, etc. We indicate that these two types of distributions are functional inverses of each other, and specify this link, firs...

We report the case of a 7 year old girl who developed central hypoventilation following pertussis and who was treated by negative pressure ventilation using a new portable tank respirator. We believe this is the first reported case of central hypoventilation following pertussis successfully treated by intermittent negative pressure ventilation.

We are undertaking mechanical ventilation (MV) seriously since three years, begining with infants and children and then including neonates also. MV is provided to about 15 cases every month presently, 1 to 3 cases receiving it at a time. MV typically lasts for a few days, longest duration having been 37 days. Overall survival of 30% in 1992 is steadily improving. The following presentation of o...

The success of the Green Revolution in closing the gap between world population and food production was principally achieved by increasing crop productivity in favorable areas. However, this success has been limited in the rainfed systems, which are prone to frequent droughts and other abiotic stresses. Worldwide, drought affects approximately 23 million hectares of rainfed rice. Varieties comb...