Persistence of circannual cycles in a migratory bird held in constant dim light

1992 ◽  
Vol 171 (4) ◽  
Author(s):  
RebeccaL. Holberton ◽  
KennethP. Able
Keyword(s):  
Migratory Bird ◽  
Circannual Cycles ◽  
Dim Light

Applying radar technology to migratory bird conservation and management: Strengthening and expanding a collaborative

2007 ◽  
Author(s):  
Janet M. Ruth ◽  
Albert Manville ◽  
Ron Larkin ◽  
Wylie C. Barrow ◽  
Lori Johnson-Randall ◽  
...  
Keyword(s):  
Migratory Bird ◽  
Bird Conservation ◽  
Conservation And Management

Disturbing Gtp-Binding Protein Function Through Microinjection Into The Visual Cell Of Limulus

1992 ◽  
Vol 47 (11-12) ◽  
pp. 915-921 ◽  
Author(s):  
Henmg Stieve ◽  
Barbara Niemeyer ◽  
Klaus Aktories ◽  
Heidi E. Hamm
Keyword(s):  
Monoclonal Antibody ◽  
G Protein ◽  
Protein Function ◽  
Clostridium Botulinum ◽  
Functional Role ◽  
Electrical Response ◽  
Visual Cell ◽  
Gtp Binding ◽  
Dim Light ◽  
Ventral Nerve Photoreceptor

We have tested the action of three agents microinjected into the ventral nerve photoreceptor of Limulus on the electrical response to dim light. 1. A monoclonal antibody (mAb 4 A) against the Gɑ subunit of frog transducin reduces the size of the receptor current to 60%, suggesting an interaction with Gɑ in the Limulus photoreceptor. 2. Injection of Clostridium botulinum ADPribosyltransferase C 3 reduces the size to 46%; latency is not affected. The results imply that small GTP-binding proteins play a functional role in photoreception of invertebrates. 3. Injection of GD P-β-S reduces dose-dependently the size of the receptor current to 15% and prolongs the latency to 200%, presumably by reducing number and rate of G-protein activations

scholarly journals Temporal changes in reproductive success and optimal breeding decisions in a long-distance migratory bird

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cynthia Reséndiz-Infante ◽  
Gilles Gauthier
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Environmental Changes ◽  
Migratory Bird ◽  
Laying Date ◽  
Negative Consequences ◽  
Breeding Phenology ◽  
Additional Time ◽  
Long Distance ◽  
Seasonal Decline

AbstractMany avian migrants have not adjusted breeding phenology to climate warming resulting in negative consequences for their offspring. We studied seasonal changes in reproductive success of the greater snow goose (Anser caerulescens atlantica), a long-distance migrant. As the climate warms and plant phenology advances, the mismatch between the timing of gosling hatch and peak nutritive quality of plants will increase. We predicted that optimal laying date yielding highest reproductive success occurred earlier over time and that the seasonal decline in reproductive success increased. Over 25 years, reproductive success of early breeders increased by 42%, producing a steeper seasonal decline in reproductive success. The difference between the laying date producing highest reproductive success and the median laying date of the population increased, which suggests an increase in the selection pressure for that trait. Observed clutch size was lower than clutch size yielding the highest reproductive success for most laying dates. However, at the individual level, clutch size could still be optimal if the additional time required to acquire nutrients to lay extra eggs is compensated by a reduction in reproductive success due to a delayed laying date. Nonetheless, breeding phenology may not respond sufficiently to meet future environmental changes induced by warming temperatures.

Sensor-Based Estimation of Dim Light Melatonin Onset Using Features of Two Time Scales

2021 ◽  
Vol 2 (3) ◽  
pp. 1-15
Author(s):  
Cheng Wan ◽  
Andrew W. Mchill ◽  
Elizabeth B. Klerman ◽  
Akane Sano
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
Light Exposure ◽  
Biological Activities ◽  
Second Step ◽  
Sampled Data ◽  
Dim Light Melatonin Onset ◽  
Dim Light ◽  
Using Data ◽  
Mean Square Errors

Circadian rhythms influence multiple essential biological activities, including sleep, performance, and mood. The dim light melatonin onset (DLMO) is the gold standard for measuring human circadian phase (i.e., timing). The collection of DLMO is expensive and time consuming since multiple saliva or blood samples are required overnight in special conditions, and the samples must then be assayed for melatonin. Recently, several computational approaches have been designed for estimating DLMO. These methods collect daily sampled data (e.g., sleep onset/offset times) or frequently sampled data (e.g., light exposure/skin temperature/physical activity collected every minute) to train learning models for estimating DLMO. One limitation of these studies is that they only leverage one time-scale data. We propose a two-step framework for estimating DLMO using data from both time scales. The first step summarizes data from before the current day, whereas the second step combines this summary with frequently sampled data of the current day. We evaluate three moving average models that input sleep timing data as the first step and use recurrent neural network models as the second step. The results using data from 207 undergraduates show that our two-step model with two time-scale features has statistically significantly lower root-mean-square errors than models that use either daily sampled data or frequently sampled data.

scholarly journals Author Correction: Age-dependent carry-over effects in a long-distance migratory bird

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cosme López Calderón ◽  
Javier Balbontín Arenas ◽  
Keith A. Hobson ◽  
Anders Pape Møller
Keyword(s):  
Migratory Bird ◽  
Long Distance ◽  
Age Dependent ◽  
Carry Over

scholarly journals Divergent Importance of Chronobiological Considerations in High- and Low-dose Melatonin Therapies

Diseases ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 18
Author(s):  
Rüdiger Hardeland
Keyword(s):  
Phase Response Curve ◽  
Sleep Onset ◽  
Melatonin Receptors ◽  
Duration Of Action ◽  
Circadian Oscillators ◽  
Protective Actions ◽  
Circadian Control ◽  
Dim Light ◽  
Poor Individual ◽  
Specific Phase

Melatonin has been used preclinically and clinically for different purposes. Some applications are related to readjustment of circadian oscillators, others use doses that exceed the saturation of melatonin receptors MT1 and MT2 and are unsuitable for chronobiological purposes. Conditions are outlined for appropriately applying melatonin as a chronobiotic or for protective actions at elevated levels. Circadian readjustments require doses in the lower mg range, according to receptor affinities. However, this needs consideration of the phase response curve, which contains a silent zone, a delay part, a transition point and an advance part. Notably, the dim light melatonin onset (DLMO) is found in the silent zone. In this specific phase, melatonin can induce sleep onset, but does not shift the circadian master clock. Although sleep onset is also under circadian control, sleep and circadian susceptibility are dissociated at this point. Other limits of soporific effects concern dose, duration of action and poor individual responses. The use of high melatonin doses, up to several hundred mg, for purposes of antioxidative and anti-inflammatory protection, especially in sepsis and viral diseases, have to be seen in the context of melatonin’s tissue levels, its formation in mitochondria, and detoxification of free radicals.

Evaluation of a two‐season banding program to estimate and model migratory bird survival

2021 ◽  
Author(s):  
Patrick K. Devers ◽  
Robert L. Emmet ◽  
G. Scott Boomer ◽  
Guthrie S. Zimmerman ◽  
J. Andrew Royle
Keyword(s):  
Migratory Bird
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