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This study aimed (1) to examine the current status of psychological distress experienced by neonatal intensive care unit (NICU) nurses in supporting bereaved families, (2) to identify the factors associated with psychological distress, and (3) to understand the professional characteristics of nurses experiencing high psychological distress by comparing the study results with those of pediatricians.We sent questionnaires to 64 NICUs. The psychological distress of nurses was classified into two groups based on the frequency of psychological distress experienced and analyzed using the χ2 test and Fisher's exact test. A multiple logistic regression analysis was used to investigate the factors related to psychological distress.Of the 384 nurse respondents, 190 (49.5%) reported having supported bereaved families, 169 of who were included in the analysis. A total of 123 nurses (72.8%) reported high levels of psychological distress. Our study revealed that the use of coping methods is associated with high psychological distress. The comparison with pediatricians revealed that nurses were significantly more likely to be female and had fewer years of working experience. Nurses were also significantly more likely to use coping methods and to experience high psychological distress.Clarifying the coping methods for psychological distress in supporting bereaved families may be necessary, and nurses need to identify appropriate coping methods. In nursing education, information on psychological distress related to children's deaths and bereavement care should be conveyed from the early stage and nurses must obtain preliminary knowledge. The creation of a bereavement follow-up system is recommended.

The nature of the dose-response relationship in the low dose zone and how this concept may be used by regulatory agencies for science-based policy guidance and risk assessment practices are addressed here by using the effects of surface ozone (O3) on plants as a key example for dynamic ecosystems sustainability. This paper evaluates the current use of the linear non-threshold (LNT) dose-response model for O3. The LNT model has been typically applied in limited field studies which measured damage from high exposures, and used to estimate responses to lower concentrations. This risk assessment strategy ignores the possibility of biological acclimation to low doses of stressor agents. The upregulation of adaptive responses by low O3 concentrations typically yields pleiotropic responses, with some induced endpoints displaying hormetic-like biphasic dose-response relationships. Such observations recognize the need for risk assessment flexibility depending upon the endpoints measured, background responses, as well as possible dose-time compensatory responses. Regulatory modeling strategies would be significantly improved by the adoption of the hormetic dose response as a formal/routine risk assessment option based on its substantial support within the literature, capacity to describe the entire dose-response continuum, documented explanatory dose-dependent mechanisms, and flexibility to default to a threshold feature when background responses preclude application of biphasic dose responses. Capsule: The processes of ozone hazard and risk assessment can be enhanced by incorporating hormesis into their principles and practices. © 2018 Elsevier B.V.

The United States Environmental Protection Agency (US EPA) has recently proposed changes to strengthen the transparency of its pivotal regulatory science policy and procedures. In this context, the US EPA aims to enhance the transparency of dose-response data and models, proposing to consider for the first time non-linear biphasic dose-response models. While the proposed changes have the potential to lead to markedly improved ecological risk assessment compared to past and current approaches, we believe there remain open issues for improving the quality of ecological risk assessment, such as the consideration of adaptive, dynamic and interactive effects. Improved risk assessment including adaptive and dynamic non-linear models (beyond classic threshold models) can enhance the quality of regulatory decisions and the protection of ecological health. We suggest that other countries consider adopting a similar scientific-regulatory posture with respect to dose-response modeling via the inclusion of non-linear biphasic models, that incorporate the dynamic potential of biological systems to adapt (i.e., enhancing positive biological endpoints) or maladapt to low levels of stressor agents.

We measured leaf photosynthetic traits in shade-grown seedlings of four tree species native to northern Japan, raised under an elevated CO2 condition, to investigate the effects of elevated CO2 on shade tolerance of deciduous broadleaf tree species with different successional traits. We considered Betula platyphylla var. japonica and Betula maximowicziana as pioneer species, Quercus mongolica var. crispula as a mid-successional species, and Acer mono as a climax species. The plants were grown under shade conditions (10% of full sunlight) in a CO2-regulated phytotron. Light compensation points (LCPs) decreased in all tree species when grown under elevated CO2 (720 μmol·mol−1), which were accompanied by higher apparent quantum yields but no photosynthetic down-regulation. LCPs in Q. mongolica and A. mono grown under elevated CO2 were lower than those in the two pioneer birch species. The LCP in Q. mongolica seedlings was not different from that of A. mono in each CO2 treatment. However, lower dark respiration rates were observed in A. mono than in Q. mongolica, suggesting higher shade tolerance in A. mono as a climax species in relation to carbon loss at night. Thus, elevated CO2 may have enhanced shade tolerance by lowering LCPs in all species, but the ranking of shade tolerance related to successional traits did not change among species under elevated CO2, i.e. the highest shade tolerance was observed in the climax species (A. mono), followed by a gap-dependent species (Q. mongolica), while lower shade tolerance was observed in the pioneer species (B. platyphylla and B. maximowicziana).