Bipolar mood cycles and lunar tidal cycles.
Ontology highlight
ABSTRACT:
SUBMITTER: Wehr TA
PROVIDER: S-EPMC5524624 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Reproduction in iteroparous marine organisms is often timed with abiotic cycles and may follow lunar, tidal amplitude, or daily cycles. Among intertidal marine invertebrates, decapods are well known to time larval release to coincide with large amplitude nighttime tides, which minimizes the risk of predation. Such bimonthly cycles have been reported for few other intertidal invertebrates. We documented the reproduction of 6 gastropod species from Panama to determine whether they demonstrate reproductive cycles, whether these cycles follow a 2-week cycle, and whether cycles are timed so that larval release occurs during large amplitude tides. Two of the species (Crepidula cf. marginalis and Nerita scabricosta) showed nonuniform reproduction, but without clear peaks in timing relative to tidal or lunar cycles. The other 4 species show clear peaks in reproduction occurring every 2 weeks. In 3 of these species (Cerithideopsis carlifornica var. valida, Littoraria variegata, and Natica chemnitzi), hatching occurred within 4 days of the maximum amplitude tides. Siphonaria palmata exhibit strong cycles, but reproduction occurred during the neap tides. Strong differences in the intensity of reproduction of Cerithideopsis carlifornica, and in particular, Littoraria variegata, between the larger and smaller spring tides of a lunar month indicate that these species time reproduction with the tidal amplitude cycle rather than the lunar cycle. For those species that reproduce during both the wet and dry seasons, we found that reproductive timing did not differ between seasons despite strong differences in temperature and precipitation. Overall, we found that most (4/6) species have strong reproductive cycles synchronized with the tidal amplitude cycle and that seasonal differences in abiotic factors do not alter these cycles.
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Project description:A long-standing question in Earth Science is the extent to which seismic and volcanic activity can be regulated by tidal stresses, a repeatable and predictable external excitation induced by the Moon-Sun gravitational force. Fortnightly tides, a ~14-day amplitude modulation of the daily tidal stresses that is associated to lunar cycles, have been suggested to affect volcano dynamics. However, previous studies found contradictory results and remain mostly inconclusive. Here we study how fortnightly tides have affected Ruapehu volcano (New Zealand) from 2004 to 2016 by analysing the rolling correlation between lunar cycles and seismic amplitude recorded close to the crater. The long-term (~1-year) correlation is found to increase significantly (up to confidence level of 5-sigma) during the ~3 months preceding the 2007 phreatic eruption of Ruapehu, thus revealing that the volcano is sensitive to fortnightly tides when it is prone to explode. We show through a mechanistic model that the real-time monitoring of seismic sensitivity to lunar cycles may help to detect the clogging of active volcanic vents, and thus to better forecast phreatic volcanic eruptions.
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Project description:ObjectiveThe Course and Outcome of Bipolar Youth study found that children and adolescents with bipolar spectrum disorders followed 1 of 4 distinct mood trajectories over 8 years of follow-up, with as many as 25% of participants showing a predominantly euthymic course. We evaluated whether similar patterns of illness course are observed in adolescents with bipolar I and II disorder who participated in a 2-year clinical trial.MethodA total of 144 adolescents with bipolar I or II disorder, identified shortly after a mood episode, were assessed over a 2-year period. Participants were randomly assigned to one of 2 psychosocial family treatments during the first 9 months of the study, and pharmacotherapy was provided throughout the 2 years. Using latent class growth analyses, we classified participants into distinct courses of illness based on mood ratings collected over the 2 years. We examined demographic and illness variables as predictors of these course classifications.ResultsLatent class growth analyses indicated four mood trajectories: "predominantly euthymic" (29.9% of sample), "ill with significantly improving course" (11.1%), "moderately euthymic" (26.4%), and "ill with moderately improving course" (32.6%). Adolescents in these classes were euthymic 77.7%, 53.6%, 44.1%, and 18.6% of the weeks of follow-up, respectively. Psychosocial treatment condition and baseline medication exposure were not associated with trajectories. However, youth with more severe baseline depressive symptoms, suicidality, lower quality of life scores, and minority race/ethnicity had more symptomatic courses of illness over time.ConclusionA substantial proportion (25%-30%) of youth with bipolar I or II disorder maintain euthymic states over extended periods of follow-up. Identifying youth who are more and less likely to remain stable over time may help guide psychosocial and pharmacological treatments after an illness episode.Clinical trial registration informationEffectiveness of Family-Focused Treatment Plus Pharmacotherapy for Bipolar Disorder in Adolescents; https://clinicaltrials.gov/; NCT00332098.
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