This paper develops a framework and proposes heuristic dynamic policies for scheduling patient appointments, taking into account the fact that patients may cancel or not show up for their appointments. In a simulation study that considers a model clinic, which is created using data obtained from an actual clinic, we find that the heuristics proposed outperform all the other benchmark policies, particularly when the patient load is high compared with the regular capacity. Supporting earlier findings in the literature, we find that the open access policy, a recently proposed popular scheduling paradigm that calls for "meeting today's demand today," can be a reasonable choice when the patient load is relatively low.service operations, health-care management, stochastic methods

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This paper investigates pert networks with independent and exponentially distributed activity durations. We model such networks as finite-state, absorbing, continuous-time Markov chains with upper triangular generator matrices. The state space is related to the network structure. We present simple and computationally stable algorithms to evaluate the usual performance criteria: the distribution and moments of project completion time, the probability that a given path is critical, and other related performance measures. In addition, we algorithmically analyze conditional performance measures—for example, project completion time, given a critical path—and present computational results. We then study extensions both to resource-constrained pert networks and to a special class of nonexponential pert networks.

A new class of multivariate phase type distributions (denoted by MPH*) is defined, based upon the total accumulated reward until absorption in a finite state, continuous time Markov chain. This new class is shown to be a strict superset of the class of multivariate phase type distributions MPH introduced by Assaf, Langberg, Savits and Shaked. A conjectured property (viz, closure under finite convolutions) of the class MPH is proved using the class MPH* defined here. Computational techniques for the distributions in MPH* are discussed. Closure properties of MPH* are stated and an open problem is discussed.

SUMMARY Set2-mediated histone methylation at H3K36 regulates diverse activities including DNA repair, mRNA splicing and suppression of inappropriate (cryptic) transcription. Although failure of Set2 to suppress cryptic transcription has been linked to decreased life span, the extent to which cryptic transcription influences other cellular functions is poorly understood. Here, we uncover a role for H3K36 methylation in the regulation of the nutrient stress response pathway. We found the transcriptional response to nutrient stress was dysregulated in SET2-deleted (set2Δ) cells and was correlated with genome-wide bi-directional cryptic transcription that originated from within gene bodies. Antisense transcripts arising from these cryptic events extended into the promoters of the genes from which they arose and were associated with decreased sense transcription under nutrient stress conditions. These results suggest that Set2-enforced transcriptional fidelity is critical to the proper regulation of inducible and highly regulated transcription programs.