In problems of maintenance optimization, it is convenient to assume that repairs are equivalent to replacements and that systems or objects are therefore brought back into an as-good-as-new state after each repair. Standard results in renewal theory may then be applied for determining optimal maintenance policies. In practice, there are many situations in which this assumption can not be made. ...

The design or scale-up of heat transfer systems in fluidized beds require estimation of the effective heat transfer coefficient on heat transfer surfaces in contact with the fluidized medium. In this study, the effects of operational parameters on bed-to-wall heat transfer in CFBs is investigated such as solids volume fraction, particle diameter, suspension density, superficial velocity and sol...

In the terms of operational calculus the probability characteristics of direct and reverse residual renewal time of alternating renewal process, where renewal time depends on life-time, are found. 1. Definitions, Motivations and Formulation of the Problem 1.1 According to [1] let’s consider a system which fails after random life-time X1 and is fully renewed after the lapse of random time Y1. Th...

Pavlovian conditioning models have influenced the development of cue exposure treatments for drug abuse. However, poor maintenance of extinction performance (renewal) after treatment is a common problem. A treatment-analogue experiment tested the role of context in renewal, as well as a potential strategy for reducing renewal. Seventy-eight social drinkers completed extinction trials to reduce ...

Evidence continues to accumulate showing that tumors contain a minority population of cells responsible for tumor initiation, growth, and recurrence. These are termed "cancer stem cells" (CSCs). Functional assays have identified the self-renewal and tumor-initiation capabilities of CSCs. Moreover, recent studies have revealed that these CSCs is responsible for chemotherapy resistance within a t...

The following problem in risk theory is considered. An insurance company, endowed with an initial capital a . 0, receives insurance premiums and pays out successive claims. The losses occur according to renewal process. At any moment, the company may broaden or narrow down the offer, what entails the change of the parameters. This change concerns the rate of income, the intensity of renewal pro...

While hematopoietic stem cell (HSC) self-renewal is well studied, it remains unknown whether distinct control mechanisms enable HSC divisions that generate progeny cells with specific lineage bias. Here, we report that the monocytic transcription factor MafB specifically restricts the ability of M-CSF to instruct myeloid commitment divisions in HSCs. MafB deficiency specifically enhanced sensit...

Hydra's unlimited life span has long attracted attention from natural scientists. The reason for that phenomenon is the indefinite self-renewal capacity of its stem cells. The underlying molecular mechanisms have yet to be explored. Here, by comparing the transcriptomes of Hydra's stem cells followed by functional analysis using transgenic polyps, we identified the transcription factor forkhead...