3 research outputs found
The pathogenicity test to confirm that <i>C. cladosporioides</i> could hyperparasite <i>Pst</i>.
No full textA, B: CK1, wheat leaves (Cultivar: MingXian169) inoculated with C. cladosporioides, 14 dpi, without symptoms; C, D: CK2, Symptoms on wheat leaves (MingXian169) inoculated with CYR32, 20 dpi; E, F, G: Pustules on wheat leaves (same cultivar and race as above) inoculated at 14 dpi with C. cladosporioides suspension. Symptoms at 5d, 7d and 9d later.</p
Stopped Myopic Policies in Some Inventory Models with Generalized Demand Processes
No full textThis paper considers single-item inventory systems with immediate delivery and no economies of scale. Bounds are provided on the value loss relative to optimal cost for restricting attention to the class of inventory stocking policies that behave myopically up to a specified stopping time. The stopping time may be random, and may depend on demand histories as well as information exogenous to the firm. The bounds are robust to the nature of the demand process faced after the stopping time, so are applicable when the statistics of demand after the stopping time are unknown. Stopping times that are large with high probability imply that near-term decisions are completely specified with high probability. The general bounding results allow one to consider demand processes that may otherwise be analytically intractable. It is shown that the class of demand models for which the assumption of additive i.i.d. shocks is appropriate is the same class admitting effective myopic stocking policies. The bounds also make rigorous the intuitive notion that myopic policies are least effective in systems with precipitous drops in demand coupled with an inability to recover cash invested in inventory. The option of selling inventory at discount is a reality in many real systems and enhances the attractiveness of the myopic stocking policy. In numerical examples, the myopic policy is shown to be an effective competitor in a range of systems for which optimal policies are not known. The results suggest that for systems with immediate delivery, no economies of scale, and no currently known optimal policy, the myopic stocking rule is a reasonable default policy to adopt.inventory policies under uncertainty, dependent demand, approximations, Markov models: dynamic programming
Solid Phase Dosing and Sampling Technique To Determine Partition Coefficients of Hydrophobic Chemicals in Complex Matrixes
No full textDetermination of polymer−water and dissolved organic
carbon (DOC)−water distribution coefficients of very
hydrophobic chemicals (log KOW > 6) is not straightforward.
Poor water solubility of the test compounds complicates
the spiking and analysis of actual freely dissolved
concentrations. By dosing a system via a PDMS−fiber
and monitoring the depletion in the polymer, spiking and
analysis of concentrations in the aqueous phase are avoided,
and sorption to the polymer and other hydrophobic
phases can be determined easily and accurate. In this
publication we report the determination of poly(dimethylsiloxane) (PDMS)−water, and Aldrich humic acid−water distribution coefficients for six PAHs with log KOW
values varying from 4.56 to 6.85. The distribution coefficients
to a PDMS fiber (log Kf) and the DOC (log KDOC) range
from 3.86 to 5.39 and 4.78 to 7.43, respectively. Even for
the most hydrophobic compounds, the distribution coefficients
show small standard errors (≤0.05 log units). Therefore,
this method might be applied to determine sorption coefficients
of numerous, even more hydrophobic compounds, to
humic acids as well as other dissolved hydrophobic matrixes
