Temporal sensing

Dusenbery, D. B., Spatial sensing of stimulus gradients can be superior to temporal sensing for free-swimming bacteria, Biophys. J., 74, 2272, 1998. 

The first question that must be addressed concerns the stability of the aqueous complex (hereafter referred to as the aquaion). The stability, though usually thought of in a temporal sense, is related, albeit indirectly, to the real space structure at the level of the partial radial distribution functions ga r). This measures the probability of finding a /3-type particle at a distance r from an a-type particle placed at the origin. To understand gap r) quantitatively, consider an a-type particle at the origin and ask what is the average number of /3-type particles that occupy a spherical shell of radius r and thickness dr at an instant of time. That number is given by... 

Strata may be spatial, temporal, or determined by other relevant criteria. For example, in the spatial sense, a series of strata could comprise discrete areas associated with a study location, each with different geology, or different topography, or different history of contamination, or different soils (or aquatic sediments), or waters sampled at different depths within a lake to take account of stratification or, in an estuary, salinity gradient. See Ref. 5 for more detail of stratification issues in water sampling. In the temporal sense, different strata could comprise different seasons, or portions of the diurnal cycle, or time periods relative to a process such as an upstream effluent release. 

The simplicity of bacterial tactic behavior makes it amenable to study by a variety of experimental methods. Some of these monitor the movement of populations of cells, other focus on individual cells. The temporal sensing mechanism makes it possible to study cells that make no net movement in a gradient, a capability that enormously simplifies the task of delivering stimuli and monitoring responses of cells that do not keep running out of the microscope field. 

In the NCI, one is frequently asked for the status of a chemical which is somewhere in the multi-year testing cycle. In such a context, "status" implies a skeletal description of the data on the compound along with its position in a temporal sense (what has been done what remains to be done ). Also loaded into the idea is some sort of a performance rating. Has it failed trials Is it expected to fail trials Will it make it as far as the clinic And so on. 

The two genes appear to be, at least in a temporal sense, coordinately activated. Because of the simultaneous appearance at G,(3) of both repressor and inducibility, it seems likely that the inducer acts at least indirectly to antagonize the posttranscriptional repressor. Furthermore, the transcriptional control of the S (and R) gene, which does exist, is not steroid-sensitive. Regulation of TAT gene expression clearly occurs at the posttranscriptional level, and the circumstantial evidence suggests that the steroid inducer acts upon the same posttranscriptional function. 

Physical entrapment is the simplest, since it only involves radiation polymerization of monomers polymers, or radiation crosslinking of polymers. However, it is very important that either a significant pore structure exist in the final product or that it be in a finely divided form, so as to provide access for other biomolecules to reach the immobilized biomolecule, or vice versa. (The word immobilization refers in a temporal sense to the suddenly lowered mobility of the biological species it may never leach out or it may gradually dissolve into the surrounding medium. In either case, it is considered to have been immobilized .)... 

Hybrid methods learn from the pros and cons of classical and quantum methods and try to combine the best features of both. These methods are of two categories (1) methods that are hybrid in a temporal sense, mixing electronic structure calculations with MD methods and (2) methods that are spatially hybrid, applying different methods in different physical regions of a molecule or computational domain. Car-Parrinello MD (CPMD) (Car and Parrinello 1985) and related methods such as... 

The word rate here is used not in a temporal sense but in a spatial sense, as in energy per unit crack area this choice conforms witii tiie terminology in tiie literature. 

The present findings may also be relevant to the long standing debate as to whether a prediction in the temporal sense should serve as a means of validating a theory. As many authors have emphasized, predictions and retrodictions are logically equivalent. The only advantage offered by predictions is a psychological one. 

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