Discrete ordinates problems with an infinite exterior medium (reflector) can be more efficiently computed by eliminating grid cells in the exterior medium and applying a matrix albedo boundary condition. The albedo matrix is a discretized bidirectional reflection distribution function (BRDF) that accounts for the angular quadrature set, spatial quadrature method, and spatial grid that would hav...

Let T : I ?! I be a Lasota-Yorke map on the interval I, let Y be a non trivial sub-interval of I and g 0 : I ?! R + , be a strictly positive potential which belongs to BV and admits a conformal measure m. We give constructive conditions on Y ensuring the existence of absolutely continuous (w.r.t. m) conditionally invariant probability measures to non absorption in Y. These conditions imply also...

anastomotic leakage after total gastrectomy with local decontamination. A prospective, randomized, doubleblind, placebo-controlled multicenter trial. Ann Surg 1997; 225: 172–180. 21 Stoutenbeek CP, van Saene HK, Zandstra DF. Prevention of multiple organ failure by selective decontamination of the digestive tract in multiple trauma patients. In: Faist E, Baue AE, Schildberg FW, eds. The Immune C...

A case is made for the pathophysiological importance of the cerebral serotonergic neurons in the hyperventilation syndrome (HVS). Their function depends on the systemic L-tryptophan metabolism. The role of L-tryptophan metabolism is studied in 13 HVS patients, by administration of pyridoxine 125 mg t.i.d. and L-tryptophan two grams for four weeks. The xanthurenic acid excretion (XA) is measured...