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Author Youngstedt, S.D.; Elliott, J.A.; Kripke, D.F. url  doi
openurl 
  Title Human Circadian Phase-Response Curves for Exercise Type Journal Article
  Year 2019 Publication The Journal of Physiology Abbreviated Journal J Physiol  
  Volume (down) 597 Issue 8 Pages 2253-2268  
  Keywords Human Health; Circadian Rhythm; Exercise  
  Abstract KEY POINTS: Exercise elicits circadian phase-shifting effects, but additional information is needed. The phase-response curve describing the magnitude and direction of circadian rhythm phase shifts depending on the time of the zeigeber (time cue) stimulus is the most fundamental chronobiological tool for alleviating circadian misalignment and related morbidity. 51 older and 48 young adults followed a circadian rhythms measurement protocol for up to 5.5 days, and performed 1 h of moderate treadmill exercise for 3 consecutive days at one of 8 times of day/night. Temporal changes in the phase of 6-sulphatoxymelatonin (aMT6s) were measured from evening onset, cosine acrophase, morning offset, and duration of excretion, establishing significant PRCs for aMT6 onset and acrophase with large phase delays from 7-10 PM and large phase advances at both 7 AM and 1-4 PM. Along with known synergism with bright light, the above PRCs with a second phase advance region (afternoon) could support both practical and clinical applications. ABSTRACT: Although bright light is regarded as the primary circadian zeitgeber, its limitations support exploring alternative zeitgebers. Exercise elicits significant circadian phase-shifting effects, but fundamental information regarding these effects is needed. The primary aim of this study was to establish phase-response curves (PRC) documenting the size and direction of phase shifts in relation to the circadian time of exercise. Aerobically fit older (n = 51, 59-75 y) and young adults (n = 48, 18-30 y) followed a 90-min laboratory ultra-short sleep wake cycle (60 min wake/30 min sleep) for up to 5 (1/2) days. At the same clock time on three consecutive days, each participant performed 60 min of moderate treadmill exercise (65-75% of heart rate reserve) at one of 8 times of day/night. To describe PRCs, phase shifts were measured for the cosine-fitted acrophase of urinary 6-sulphatoxymelatonin (aMT6s), as well as for the evening rise, morning decline, and change in duration of aMT6s excretion. Significant PRCs were found for aMT6s acrophase, onset and duration, with peak phase advances corresponding to clock times of 7 AM and 1PM-4PM, delays from 7 PM-10 PM, and minimal shifts around 4 PM and 2 AM. There were no significant age or sex differences. The amplitudes of the aMT6s onset and acrophase PRCs are comparable to expectations for bright light of equal duration. The phase advance to afternoon exercise and the exercise-induced PRC for change in aMT6s duration are novel findings. The results support further research exploring additive phase shifting effects of bright light and exercise and health benefits. This article is protected by copyright. All rights reserved.  
  Address Department of Psychiatry, University of California, San Diego, CA  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3751 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30784068 Approved no  
  Call Number GFZ @ kyba @ Serial 2230  
Permanent link to this record
 

 
Author Gatford, K.L.; Kennaway, D.J.; Liu, H.; Kleemann, D.O.; Kuchel, T.R.; Varcoe, T.J. url  doi
openurl 
  Title Simulated shift work disrupts maternal circadian rhythms and metabolism, and increases gestation length in sheep Type Journal Article
  Year 2019 Publication The Journal of Physiology Abbreviated Journal J Physiol  
  Volume (down) 597 Issue 7 Pages 1889-1904  
  Keywords Animals; *Circadian Rhythm; Female; Fetal Development; Pregnancy; *Pregnancy, Animal/physiology; Pregnancy, Multiple; Sheep/*physiology; *Shift Work Schedule; Sleep/*physiology; *circadian rhythms; *fetus; *maternal; *pregnancy; *sheep; *shift work  
  Abstract KEY POINTS: Shift work impairs metabolic health, although its effects during pregnancy are not well understood We evaluated the effects of a simulated shift work protocol for one-third, two-thirds or all of pregnancy on maternal and pregnancy outcomes in sheep. Simulated shift work changed the timing of activity, disrupted hormonal and cellular rhythms, and impaired maternal glucose tolerance during early pregnancy. Gestation length was increased in twin pregnancies, whereas singleton lambs were lighter at a given gestational age if mothers were subjected to shift work conditions in the first one-third of pregnancy. Exposure to rotating night and day shifts, even if only in early pregnancy, may adversely affect maternal metabolic and pregnancy outcomes. ABSTRACT: Shift workers are at increased risk of developing type 2 diabetes and obesity; however, the impact during pregnancy on maternal metabolism is unknown. Using a large animal model, we assessed the impact of simulated shift work (SSW) exposure during pregnancy on maternal circadian rhythms, glucose tolerance and pregnancy outcomes. Following mating, ewes were randomly allocated to a control photoperiod (CON 12 h light, 12 h dark) or to SSW, where the timing of light exposure and food presentation was reversed twice each week for one-third, two-thirds or all of pregnancy. Maternal behaviour followed SSW cycles with increased activity during light exposure and feeding. Melatonin rhythms resynchronized within 2 days of the photoperiod shift, whereas peripheral circadian rhythms were arrhythmic. SSW impaired glucose tolerance (+29%, P = 0.019) and increased glucose-stimulated insulin secretion (+32%, P = 0.018) in ewes with a singleton fetus in early but not late gestation. SSW exposure did not alter rates of miscarriage or stillbirth, although it extended gestation length in twin pregnancies (+2.4 days, P = 0.032). Relative to gestational age, birth weight was lower in singleton progeny of SSW than CON ewes (-476 g, P = 0.016). These results have implications for the large number of women currently engaged in shift work, and further studies are required to determine progeny health impacts.  
  Address Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3751 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30671970; PMCID:PMC6441904 Approved no  
  Call Number GFZ @ kyba @ Serial 3136  
Permanent link to this record
 

 
Author Rahman, S.A.; St Hilaire, M.A.; Gronfier, C.; Chang, A.-M.; Santhi, N.; Czeisler, C.A.; Klerman, E.B.; Lockley, S.W. url  doi
openurl 
  Title Functional decoupling of melatonin suppression and circadian phase resetting in humans Type Journal Article
  Year 2018 Publication The Journal of Physiology Abbreviated Journal J Physiol  
  Volume (down) 596 Issue 11 Pages 2147-2157  
  Keywords Human Health  
  Abstract KEY POINTS: There is assumed to be a monotonic association between melatonin suppression and circadian phase resetting induced by light exposure. We tested the association between melatonin suppression and phase resetting in humans. Sixteen young healthy participants received nocturnal bright light ( approximately 9500 lux) exposure of continuous or intermittent patterns, and different durations ranging from 12 min to 6.5 h. Intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every bright light stimulus in an intermittent exposure pattern induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest that phase shifts and melatonin suppression are functionally independent such that one cannot be used as a proxy measure of the other. ABSTRACT: Continuous experimental light exposures show that, in general, the conditions that produce greater melatonin suppression also produce greater phase shift, leading to the assumption that one can be used as a proxy for the other. We tested this association in 16 healthy individuals who participated in a 9-day inpatient protocol by assessing melatonin suppression and phase resetting in response to a nocturnal light exposure (LE) of different patterns: (i) dim-light control (<3 lux; n = 6) or (ii) two 12-min intermittent bright light pulses (IBL) separated by 36 min of darkness ( approximately 9500 lux; n = 10). We compared these results with historical data from additional LE patterns: (i) dim-light control (<3 lux; n = 11); (ii) single continuous bright light exposure of 12 min (n = 9), 1.0 h (n = 10) or 6.5 h (n = 6); or (iii) an IBL light pattern consisting of six 15-min pulses with 1.0 h dim-light recovery intervals between them during a total of 6.5 h (n = 7). All light exposure groups had significantly greater phase-delay shifts than the dim-light control condition (P < 0.0001). While a monotonic association between melatonin suppression and circadian phase shift was observed, intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every IBL stimulus induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest unique specificities in how light-induced phase shifts and melatonin suppression are mediated such that one cannot be used as a proxy measure of the other.  
  Address Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3751 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29707782 Approved no  
  Call Number GFZ @ kyba @ Serial 1887  
Permanent link to this record
 

 
Author Strobl, E. url  openurl
  Title The Impact of Typhoons on Economic Activity in the Philippines: Evidence from Nightlight Intensity Type Journal Article
  Year 2019 Publication ADB Economics Working Paper Series Abbreviated Journal  
  Volume (down) 589 Issue Pages  
  Keywords Remote Sensing  
  Abstract We quantify the economic impact of typhoons in the Philippines. To this end we construct a panel data set of local economic activity derived from nightlight intensity satellite images and a cell level measure of typhoon damage constructed from storm track data, a wind field model, and a stylized damage function. Our econometric results reveal that there is a statistically and potentially economically significant, albeit short- lived, impact of typhoon destruction on local economic activity. Constructing risk profiles from a 60-year historical set of storms suggests that (near) future losses in economic activity for frequent (5-year return period) and rare (50-year return period) events are likely

to range from between 1.0% and 2.5%.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ intern @ Serial 2641  
Permanent link to this record
 

 
Author Acuto, M. url  doi
openurl 
  Title We need a science of the night Type Journal Article
  Year 2019 Publication Nature Abbreviated Journal Nature  
  Volume (down) 576 Issue 7787 Pages 339  
  Keywords *Policy; *Society; *Commentary  
  Abstract (none)  
  Address Connected Cities Lab, University of Melbourne; michele.acuto(at)unimelb.edu.au  
  Corporate Author Thesis  
  Publisher Springer Nature Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31853076 Approved no  
  Call Number IDA @ john @ Serial 2792  
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