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Author Narendra, A.; Reid, S.F.; Raderschall, C.A.
Title Navigational efficiency of nocturnal Myrmecia ants suffers at low light levels Type Journal Article
Year 2013 Publication PloS one Abbreviated Journal PLoS One
Volume 8 Issue 3 Pages e58801
Keywords Adaptation, Biological/*physiology; Animals; Ants/*physiology; Australian Capital Territory; *Cues; Geographic Information Systems; Homing Behavior/*physiology; *Light; Locomotion/*physiology; Orientation/*physiology; insects
Abstract Insects face the challenge of navigating to specific goals in both bright sun-lit and dim-lit environments. Both diurnal and nocturnal insects use quite similar navigation strategies. This is despite the signal-to-noise ratio of the navigational cues being poor at low light conditions. To better understand the evolution of nocturnal life, we investigated the navigational efficiency of a nocturnal ant, Myrmecia pyriformis, at different light levels. Workers of M. pyriformis leave the nest individually in a narrow light-window in the evening twilight to forage on nest-specific Eucalyptus trees. The majority of foragers return to the nest in the morning twilight, while few attempt to return to the nest throughout the night. We found that as light levels dropped, ants paused for longer, walked more slowly, the success in finding the nest reduced and their paths became less straight. We found that in both bright and dark conditions ants relied predominantly on visual landmark information for navigation and that landmark guidance became less reliable at low light conditions. It is perhaps due to the poor navigational efficiency at low light levels that the majority of foragers restrict navigational tasks to the twilight periods, where sufficient navigational information is still available.
Address ARC Centre of Excellence in Vision Science, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia. ajay.narendra@anu.edu.au
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:23484052; PMCID:PMC3590162 Approved (up) no
Call Number IDA @ john @ Serial 117
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Author Collison, F.M.; Poe, K.
Title “Astronomical Tourism”: The Astronomy and Dark Sky Program at Bryce Canyon National Park Type Journal Article
Year 2013 Publication Tourism Management Perspectives Abbreviated Journal Tourism Management Perspectives
Volume 7 Issue Pages 1-15
Keywords Astronomy-related tourism; National parks; Night sky darkness; astrotourism; dark skies
Abstract Astronomical tourism represents a less-studied segment of sustainable tourism, where a dark night sky is the underlying resource. This article evaluates an astronomical tourism program, in this case at a national park with dark skies for observing. Bryce Canyon National Park (BCNP) in the southwestern United States has a well-developed astronomy program to serve visitors. The program consists of solar viewing during the day, multimedia evening programs, and night-time star gazing with telescopes. Depending on the specific measure used, it appears that up to 10% of park visitors may be involved with the formal Astronomy and Dark Sky Program and/or more informal astronomy activities. BCNP appears well positioned to take advantage of the dark sky attributes of the park and to educate visitors about the importance of maintaining and/or increasing the darkness of night skies. Potential future developments in the program may serve to further increase the number of visitors to BCNP.
Address School of Travel Industry Management, 1901 Ruby Lane, Liberty, MO 64068; collison(at)hawaii.edu
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ISSN 2211-9736 ISBN Medium
Area Expedition Conference
Notes Approved (up) no
Call Number IDA @ john @ Serial 128
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Author Stevens, R.G.; Brainard, G.C.; Blask, D.E.; Lockley, S.W.; Motta, M.E.
Title Adverse health effects of nighttime lighting: comments on American Medical Association policy statement Type Journal Article
Year 2013 Publication American Journal of Preventive Medicine Abbreviated Journal Am J Prev Med
Volume 45 Issue 3 Pages 343-346
Keywords American Medical Association; Cell Cycle/physiology; Circadian Rhythm/*physiology; DNA Damage/physiology; *Health Policy; Humans; Lighting/*adverse effects; United States
Abstract The American Medical Association House of Delegates in June of 2012 adopted a policy statement on nighttime lighting and human health. This major policy statement summarizes the scientific evidence that nighttime electric light can disrupt circadian rhythms in humans and documents the rapidly advancing understanding from basic science of how disruption of circadian rhythmicity affects aspects of physiology with direct links to human health, such as cell cycle regulation, DNA damage response, and metabolism. The human evidence is also accumulating, with the strongest epidemiologic support for a link of circadian disruption from light at night to breast cancer. There are practical implications of the basic and epidemiologic science in the form of advancing lighting technologies that better accommodate human circadian rhythmicity.
Address University of Connecticut Health Center, Farmington, Connecticut 06030-6325, USA. bugs@uchc.edu
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0749-3797 ISBN Medium
Area Expedition Conference
Notes PMID:23953362 Approved (up) no
Call Number IDA @ john @ Serial 130
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Author Wood, B.; Rea, M.S.; Plitnick, B.; Figueiro, M.G.
Title Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression Type Journal Article
Year 2013 Publication Applied Ergonomics Abbreviated Journal Appl Ergon
Volume 44 Issue 2 Pages 237-240
Keywords Adolescent; *Computers, Handheld; Female; Humans; Light/*adverse effects; Male; Melatonin/*biosynthesis; Photoperiod; Saliva/*metabolism; Sleep/radiation effects; Time Factors; Young Adult; melatonin
Abstract Exposure to light from self-luminous displays may be linked to increased risk for sleep disorders because these devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Thirteen participants experienced three experimental conditions in a within-subjects design to investigate the impact of self-luminous tablet displays on nocturnal melatonin suppression: 1) tablets-only set to the highest brightness, 2) tablets viewed through clear-lens goggles equipped with blue light-emitting diodes that provided 40 lux of 470-nm light at the cornea, and 3) tablets viewed through orange-tinted glasses (dark control; optical radiation <525 nm approximately 0). Melatonin suppressions after 1-h and 2-h exposures to tablets viewed with the blue light were significantly greater than zero. Suppression levels after 1-h exposure to the tablets-only were not statistically different than zero; however, this difference reached significance after 2 h. Based on these results, display manufacturers can determine how their products will affect melatonin levels and use model predictions to tune the spectral power distribution of self-luminous devices to increase or to decrease stimulation to the circadian system.
Address Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180, USA. woodb5@rpi.edu
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ISSN 0003-6870 ISBN Medium
Area Expedition Conference
Notes PMID:22850476 Approved (up) no
Call Number IDA @ john @ Serial 136
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Author Cajochen, C.; Altanay-Ekici, S.; Munch, M.; Frey, S.; Knoblauch, V.; Wirz-Justice, A.
Title Evidence that the lunar cycle influences human sleep Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 23 Issue 15 Pages 1485-1488
Keywords Adult; Aged; Cross-Sectional Studies; Electroencephalography; Female; Humans; Hydrocortisone/analysis/metabolism; Male; Melatonin/analysis/metabolism; Middle Aged; Moon; Nontherapeutic Human Experimentation; Periodicity; Saliva/metabolism; Sleep/*physiology; Sleep Stages/physiology; Young Adult
Abstract Endogenous rhythms of circalunar periodicity ( approximately 29.5 days) and their underlying molecular and genetic basis have been demonstrated in a number of marine species [1, 2]. In contrast, there is a great deal of folklore but no consistent association of moon cycles with human physiology and behavior [3]. Here we show that subjective and objective measures of sleep vary according to lunar phase and thus may reflect circalunar rhythmicity in humans. To exclude confounders such as increased light at night or the potential bias in perception regarding a lunar influence on sleep, we retrospectively analyzed sleep structure, electroencephalographic activity during non-rapid-eye-movement (NREM) sleep, and secretion of the hormones melatonin and cortisol found under stringently controlled laboratory conditions in a cross-sectional setting. At no point during and after the study were volunteers or investigators aware of the a posteriori analysis relative to lunar phase. We found that around full moon, electroencephalogram (EEG) delta activity during NREM sleep, an indicator of deep sleep, decreased by 30%, time to fall asleep increased by 5 min, and EEG-assessed total sleep duration was reduced by 20 min. These changes were associated with a decrease in subjective sleep quality and diminished endogenous melatonin levels. This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues.
Address Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4012 Basel, Switzerland. christian.cajochen@upkbs.ch
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:23891110 Approved (up) no
Call Number IDA @ john @ Serial 140
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