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Background: China is the world's largest tobacco consumer. Smoking initiation dramatically increases from teenage to adulthood. In this study, we investigated adolescents' future smoking intention at critical ages and its associated predictors. Methods: Using a longitudinal design (3 waves) across 6 months in 2016, data from 156 10th graders in two high schools in China were examined. We used latent class growth modelling to explore the heterogeneous trajectories of smoking intentions for two future age groups. Logistic regression was then used to estimate the predictors of trajectories. Results: Two trajectories and three trajectories were identified for future smoking intention in their twenties and forties, respectively. Gender, current smoking status, and mothers' and friends' smoking status all played distinct roles in future smoking intentions. Conclusions: Chinese adolescents' future intentions at critical ages are of concern. Future tobacco control should target the critical ages as well as incorporate social and cultural meanings of smoking in China. As important factors related to future smoking trajectories, gender and mothers' smoking status should also be considered in anti-smoking prevention efforts. Meanings associated with smoking status in the future should also be explored especially for female adolescents. [ABSTRACT FROM AUTHOR]

In this paper, we provide an interval of existence of critical mortality rate parameters M and b and their asymptotic expressions in allometry survival model, in the absence of age-specific mortality data. [ABSTRACT FROM AUTHOR]

This study attempts to answer the question of whether there is a ‘critical age’ after which a second contralateral cochlear implant is less likely to provide enough speech perception to be of practical use. The study was not designed to predict factors that determine successful binaural implant use, but to see if there was evidence to help determine the latest age at which the second ear can usefully be implanted, should the first side fail and become unusable. Outcome data, in the form of speech perception test results, were collected from 11 cochlear implant programmes in the UK and one centre in Australia. Forty-seven congenitally bilaterally deaf subjects who received bilateral sequential implants were recruited to the study. The study also included four subjects with congenital unilateral profound deafness who had lost all hearing in their only hearing ear and received a cochlear implant in their unilaterally congenitally deaf ear. Of those 34 subjects for whom complete sets of data were available, the majority (72%) of those receiving their second (or unilateral) implant up to the age of 13 years scored 60 per cent or above in the Bamford Kowal Bench (BKB) sentence test, or equivalent. In contrast, of those nine receiving their second or unilateral implant at the age of 15 or above, none achieved adequate levels of speech perception on formal testing: two scored 29 per cent and 30 per cent, respectively, and the rest seven per cent or less. A discriminant function analysis performed on the data suggests that it is unlikely that a second contralateral implant received after the age of 16 to 18 years will, on its own, provide adequate levels of speech perception. As more children receive sequential bilateral cochlear implants and the pool of data enlarges the situation is likely to become clearer. The results provide support for the concept of a ‘critical age’ for implanting the second ear in successful congenitally deaf unilateral cochlear implant users. This would argue against ‘preserving’ the second ear beyond a certain age, in order to use newer models of cochlear implant or for the purpose of hair cell regeneration and similar procedures in the future. The results suggest a new and more absolute reason for bilateral implantation of congenitally deaf children at an early age. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Due to the changing behavioral contexts at which social insects are exposed during the adult lifespan, they are ideal models to analyze the effect of particular sensory stimuli during young adulthood on later behavior. Specifically, our goal is to understand early influences on later foraging behavior. For that, olfactory memories were established by worker honeybees to different pre-foraging ages using either (1) classical conditioning in the proboscis extension response (PER) paradigm or (2) the offering of scented-sugar solution under different rearing conditions. By testing long-term memories (LTM) through a single PER test in workers of foraging ages (17–25 days), we found that retention of the early olfactory memories in honey bees is age-dependent and not time-dependent. Independently of the environmental conditions in which they were reared (laboratory cages or hives), bees were able to retain food-odor association from 5 days after emergence, but rarely before. In most experiments we observed a bi-modal pattern of response: bees exposed to scented-food at 5–8 and 13–16 days showed better retention than those exposed at 9–12 days. These differences disappeared for bees reared in hives. Retrieval of LTMs depending on the timing and the continuous inputs of appropriate sensory stimuli are discussed. [ABSTRACT FROM AUTHOR]

Three critical phenomena of flowering can be recognized in nature: critical age, critical initial size and critical switchover size. In order to understand the ecological significance of these flowering phenomena from the viewpoint of matter production, a simple model of flowering phenomean (critical-production model) was studied, assuming that plant flowering is controlled by the productive capacity of the plant (critical-production model, under the condition that plants forecast environmental conditions affecting matter production. Thus, we concluded that all three critical phenomena are various manifestation of the same critical-production principle. Then, using the model simulation, the reliability of each critical phenomenon for securing a given critical production was investigated in relation to the photosynthetic productivity of the habitat. The main predictions obtained from the simulation were as follows: 1) Only annual and biennial plants will show critical age phenomena, and most biennials will be facultative. 2) Among perennials, the critical initial size phenomenon will appear in low productive habitats, whereas in high productive habitats the critical switchover size phenomenon will be observed. [ABSTRACT FROM AUTHOR]