One indirect mode through which suboptimal cells could be eliminated is proposed by the "trophic theory" (Levi-Montalcini, 1987; Moreno, 2014; Raff, 1992; Simi and Ibáñez, 2010), which suggested that Darwinian-like competition among cells for limiting amounts of survival-promoting factors will lead to removal of less fit cells.
The space station presentation states that the ability to support the crew and the amount of survival time "are almost impossible to predict with certainty".
Also, both a survey [ 23] and a randomised clinical trial suggest that the amount of survival gain from statin therapy matters to patients [ 10].
It is possible that there was a degree of under-ascertainment of death in our study; however, every individual contributed a certain amount of survival time before they either died or were censored and patients were followed up annually.
This structure may introduce a certain amount of survival bias and has also created a younger HIV-infected group, which we would expect to bias away from finding differences associated with HIV.
In Drosophila, the amount of survival factor cells compete for is often not limiting, but cell selection still occurs because cells can compare their fitness directly thanks to fitness indicator proteins.
Although regimens consisting of gemcitabine in combination with erlotinib or capecitabine have shown statistically significant increases in survival duration, the small amount of survival benefit and accompanying toxicities result in difficulties related to their translation into clinically meaningful improvements (Cunningham et al, 2005; Moore et al, 2007).
Nusinersen is specifically designed to alter splicing of SMN2 pre-mRNA and thus increase the amount of functional survival motor neuron (SMN) protein that is deficient in patients with spinal muscular atrophy.
Similarly, upon application of stress induced by H2O2, cell lines expressing the mutant forms of LRRK2 exhibited a significantly lower amount of cell survival than that of the wild-type (P < 0.001)).
