We analyze theoretically and experimentally the residence time distribution of bistable systems in the presence of noise and time-delayed feedback. We explain various nonexponential features of the residence time distribution using a two-state model and obtain a quantitative agreement with an experiment based on a Schmitt trigger. The limitations of the two-state model are also analyzed theoret...

A mathematical model for the prediction of internal recirculation of complex impinging stream reactors has been presented. The model constitutes a repetition of a series of ideal plug flow reactors and CSTR reactors with recirculation. The simplicity of the repeating motif allows for the derivation of an algebraic relation of the whole system using the Laplace transform. An impinging stream...

The pharmacokinetics of nalbuphine 20 mg i.v. were studied in 10 patients undergoing lower abdominal or body surface surgery. Blood sampling was carried out for 600 min after injection and drug concentrations were measured by HPLC using electrochemical detection. Disposition was best described as a triexponential function, with a mean elimination half-life of 135.5 min. Mean residence time, cle...

[1] Transient storage processes are important to biogeochemical cycling in many streams and depend greatly upon stream fluvial structure. Fluvial geomorphic structure establishes patterns of surface water and subsurface head distributions, often driving hyporheic exchange through steps, riffles, and meanders, and controls the potential for in-channel dead zone storage in side pools, eddies, etc...

[1] Eddy diffusivities in the Labrador Sea (LS) are estimated from deep eddy resolving float trajectories, moored current meter records, and satellite altimetry. A mean residence time of 248 days in the central LS is observed with several floats staying for more than 2 years. By applying a simple random walk diffusion model, the observed distribution of float residence times in the central LS c...

After oral administration in rodents, triptolide (TP), a diterpenoid triepoxide compound, active as anti-inflammatory, immunosuppressive, anti-fertility, anti-cystogenesis, and anticancer agent, is rapidly absorbed into the blood circulation (from 5.0 to 19.5 minutes after dosing, depending on the rodent species) followed by a short elimination half-life (from about 20 minutes to less than 1 ho...

Because of high mortality caused by cardiovascular diseases, various fibrinolytic agents with diverse pharmacokinetic and pharmacodynamic properties have been developed. A novel mutated chimeric tissue plasminogen activator (mt-PA) was developed by the removal of first three domains of t-PA, insertion of GHRP sequence and mutation towards resistance to plasminogen activator inhibitor-1 (PAI-1)....

Drought reduces the carbon (C) assimilation of trees and decouples aboveground from belowground carbon fluxes, but little is known about the response of drought-stressed trees to rewetting. This study aims to assess dynamics and patterns of C allocation in beech saplings under dry and rewetted soil conditions. In October 2010, 5-year-old beech saplings from a forest site were transplanted into ...

Matamala et al. (1) recently highlighted the importance of estimating mean residence time (MRT) of fine root C for understanding soil C dynamics. Using isotopic signals of C from two CO2 experiments as a tracer, they estimated MRT of C through fine roots that ranged from 1.20 to 6.25 years. They obtained these MRT values by fitting an exponential equation to the C data with a one-pool model tha...