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Author Camus, Thomas; Zeng, Chaoshu
Title Effects of photoperiod on egg production and hatching success, naupliar and copepodite development, adult sex ratio and life expectancy of the tropical calanoid copepod Acartia sinjiensis Type Journal Article
Year 2008 Publication Aquaculture Abbreviated Journal
Volume (down) 280 Issue 1-4 Pages 220-226
Keywords animals; Acartia sinjiensis; Egg production and hatching success; Life expectancy; Naupliar and copepodite development; Photoperiod; Sex ratio
Abstract The tropical calanoid copepod Acartia sinjiensis has good potential for mass culture as live feed for reef fish larvae. The present study was conducted to evaluate the effects of photoperiod on various parameters related to A. sinjiensis productivity in culture. Five photoperiods of Light:Dark = 0:24; 6:18; 12:12; 18:6 and 24:0h were setup. Daily egg production of individual females under each photoperiod was monitored for 8 consecutive days. The females were randomly selected daily from stock cultures kept under respective photoperiods and discarded after experiment. The results showed a clear trend of increasing egg production with longer illumination period. Under constant darkness, acclimatization was evident as egg output increased steadily over the 8??day period. Statistics showed that photoperiod significantly (p < 0.005) affected mean daily egg production, with the highest egg output recorded at 18L:6D and 24L:0D (17.6 ?? 1.7 and 17.6 ?? 1.8 eggs/female/day respectively), which were significantly higher than all other treatments. Photoperiod also significantly affected 48??h egg hatching success (p < 0.005), a trend of increased hatching success with longer light phase was demonstrated. The highest hatching rate (87.2 ?? 1.4%) was recorded at 24L:0D, which was significantly higher than the 0L:24D and 6L:18D treatments but not significantly different from the second highest (85.3 ?? 2.6%) hatching rate of 18L:6D treatment. Photoperiod was further confirmed to significantly (p < 0.005) affected naupliar and copepodite development with accelerated development observed with increased illumination period of photoperiods. Mean development time from egg to adult was the shortest at 6.00 ?? 0.33 days under constant light (24L:0D), followed by 6.24 ?? 0.24??days at 18L:6D, both were significantly shorter than that of 0L:24D and 6L:18D treatments although no significantly difference was detected between themselves. Adult life expectancy was also found significantly (p < 0.005) affected by photoperiod with the shortest adult life span recorded under constant light (24L:0D) (9.4 ?? 0.4??days), which was significantly shorter than all other photoperiods tested. Adult sex ratio was the only parameter tested that was not significantly affected by photoperiod, a skewed sex ratio in favor of female was found across all photoperiod treatments. Based on results of current study, it is recommended that a photoperiod of 18L:6D being adopted for A. sinjiensis culture to maximize its productivity for aquaculture hatcheries.
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Call Number LoNNe @ schroer @ Serial 1581
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Author Stokkan, K.-A.; Folkow, L.; Dukes, J.; Neveu, M.; Hogg, C.; Siefken, S.; Dakin, S.C.; Jeffery, G.
Title Shifting mirrors: adaptive changes in retinal reflections to winter darkness in Arctic reindeer Type Journal Article
Year 2013 Publication Proceedings. Biological Sciences Abbreviated Journal Proc Biol Sci
Volume (down) 280 Issue 1773 Pages 20132451
Keywords Animals; Skyglow
Abstract Arctic reindeer experience extreme changes in environmental light from continuous summer daylight to continuous winter darkness. Here, we show that they may have a unique mechanism to cope with winter darkness by changing the wavelength reflection from their tapetum lucidum (TL). In summer, it is golden with most light reflected back directly through the retina, whereas in winter it is deep blue with less light reflected out of the eye. The blue reflection in winter is associated with significantly increased retinal sensitivity compared with summer animals. The wavelength of reflection depends on TL collagen spacing, with reduced spacing resulting in shorter wavelengths, which we confirmed in summer and winter animals. Winter animals have significantly increased intra-ocular pressure, probably produced by permanent pupil dilation blocking ocular drainage. This may explain the collagen compression. The resulting shift to a blue reflection may scatter light through photoreceptors rather than directly reflecting it, resulting in elevated retinal sensitivity via increased photon capture. This is, to our knowledge, the first description of a retinal structural adaptation to seasonal changes in environmental light. Increased sensitivity occurs at the cost of reduced acuity, but may be an important adaptation in reindeer to detect moving predators in the dark Arctic winter.
Address Department of Arctic and Marine Biology, University of Tromso, , Tromso, Norway, Institute of Ophthalmology, University College London, , 11-43 Bath Street, London EC1V 9EL, UK, Moorfields Eye Hospital, , London, UK
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ISSN 0962-8452 ISBN Medium
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Notes PMID:24174115; PMCID:PMC3826237 Approved no
Call Number LoNNe @ kyba @ Serial 1636
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Author Ikeda, Masayuki; Sagara, Masami; Inoué, Shojiro
Title Continuous exposure to dim illumination uncouples temporal patterns of sleep, body temperature, locomotion and drinking behavior in the rat Type Journal Article
Year 2000 Publication Neuroscience Letters Abbreviated Journal
Volume (down) 279 Issue 3 Pages 185-189
Keywords animals; rodents; animal behaviour
Abstract Dissociable circadian rhythms of sleep and body temperature in primates are thought to be regulated by independent oscillators whereas the uncoupling of circadian rhythms has not been well described in other mammals. Therefore, we made simultaneous recordings of non-rapid-eye-movement-sleep (NREMS), rapid-eye-movement-sleep (REMS), brain temperature, intraperitoneal temperature, locomotion and drinking activity under light-dark (LD) and continuous dim illumination (dim LL) and analyzed their interrelations. The rhythmic patterns of body temperature, locomotion and drinking were modified on the 12th circadian day of dim LL, while the mean body temperature as well as mean occurrence of drinking and locomotor activities did not change significantly. In contrast, dim LL exposure significantly increased the total time spent in NREMS during the resting phase of dim LL and increased REMS episodes during the active phase of dim LL. The diverse effects of dim LL exposure on the recorded phenomena suggest that temporal patterns of sleep were the most sensitive to perturbations of lighting and that differential oscillatory mechanisms may regulate sleep and other circadian rhythms in the rat.
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Call Number LoNNe @ schroer @ Serial 1591
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Author Bullock, B.; McGlashan, E.M.; Burns, A.C.; Lu, B.S.; Cain, S.W.
Title Traits related to bipolar disorder are associated with an increased post-illumination pupil response Type Journal Article
Year 2019 Publication Psychiatry Research Abbreviated Journal Psychiatry Res
Volume (down) 278 Issue Pages 35-41
Keywords Human Health
Abstract Mood states in bipolar disorder appear to be closely linked to changes in sleep and circadian function. It has been suggested that hypersensitivity of the circadian system to light may be a trait vulnerability for bipolar disorder. Healthy persons with emotional-behavioural traits associated with bipolar disorder also appear to exhibit problems with circadian rhythms, which may be associated with individual differences in light sensitivity. This study investigated the melanopsin-driven post-illumination pupil response (PIPR) in relation to emotional-behavioural traits associated with bipolar disorder (measured with the General Behavior Inventory) in a non-clinical group (n=61). An increased PIPR was associated with increased bipolar disorder-related traits. Specifically, the hypomania scale of the General Behavior Inventory was associated with an increased post-blue PIPR. Further, both the full hypomania and shortened '7 Up' scales were significantly predicted by PIPR, after age, sex and depressive traits were controlled. These findings suggest that increased sensitivity to light may be a risk factor for mood problems in the general population, and support the idea that hypersensitivity to light is a trait vulnerability for, rather than symptom of, bipolar disorder.
Address School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia. Electronic address: sean.cain@monash.edu
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ISSN 0165-1781 ISBN Medium
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Notes PMID:31136914 Approved no
Call Number GFZ @ kyba @ Serial 2510
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Author Baker, R.R.; Sadovy, Y.
Title The distance and nature of the light-trap response of moths Type Journal Article
Year 1978 Publication Nature Abbreviated Journal Nature
Volume (down) 276 Issue 5690 Pages 818-821
Keywords Animals
Abstract LIGHT TRAPS of various forms have been used to collect and study moths for well over 100 yr, but surprisingly little is known about how they attract moths. There has been some evaluation of the factors influencing the size of light trap catches1–5 and of the mechanics of the terminal phase of the moth's approach to a light6, but virtually nothing is understood about the light-trap response itself. Such an understanding is perhaps unnecessary when light traps are used solely to collect specimens, but becomes crucial as soon as they are used for quantitative sampling or survey work7. Of particular importance to the interpretation of such work is a knowledge of the distance from which moths orientate with respect to a light source; it seems intuitively that this distance should be fairly large. We present here the results of three experiments designed to determine the distance of response of free-flying moths to an artificial light source. Our results support Sotthibandhu's claim4 that the effective range of a 125 W mercury vapour (MV) lamp is about 3 m. They also lead to speculation concerning the behavioural meaning of the light trap response in moths.
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ISSN 0028-0836 ISBN Medium
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Notes Approved no
Call Number LoNNe @ schroer @ Serial 590
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