‘SEASONAL RHYTHMS’ OF A RURAL KURDISH VILLAGE:

2016 ◽  
pp. 42-56 ◽  
Author(s):  
Robin Bendrey ◽  
Jade Whitlam ◽  
Sarah Elliott ◽  
Kamal Rauf Aziz ◽  
Roger Matthews ◽  
...  
Keyword(s):  
Seasonal Rhythms

Seasonal rhythms of menarche in the United States: Correlates to menarcheal age, birth age, and birth month

2004 ◽  
Vol 14 (6) ◽  
pp. 184-192 ◽  
Author(s):  
Robert L. Matchock ◽  
Elizabeth J. Susman ◽  
Frederick M. Brown
Keyword(s):  
United States ◽  
The United States ◽  
Seasonal Rhythms ◽  
Menarcheal Age ◽  
Birth Month

Pineal Melatonin in Syrian Hamsters: Circadian and Seasonal Rhythms in Animals Maintained under Laboratory and Natural Conditions

1982 ◽  
Vol 35 (5) ◽  
pp. 342-348 ◽  
Author(s):  
George C. Brainard ◽  
Larry J. Petterborg ◽  
Bruce A. Richardson ◽  
Russel J. Reiter
Keyword(s):  
Natural Conditions ◽  
Seasonal Rhythms ◽  
Syrian Hamsters ◽  
Pineal Melatonin

Seasonal Rhythms in Behavior

2016 ◽  
pp. 2183-2199
Author(s):  
Zachary M. Weil ◽  
Randy J. Nelson
Keyword(s):  
Seasonal Rhythms

Photoperiod synchronizes reproduction and growth in the southern flying squirrel,Glaucomys volans

1990 ◽  
Vol 68 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Theresa M. Lee ◽  
Irving Zucker
Keyword(s):  
Body Weight ◽  
Reproductive Condition ◽  
Glaucomys Volans ◽  
Flying Squirrel ◽  
Seasonal Rhythms ◽  
Flying Squirrels ◽  
Body Weights ◽  
Natural Photoperiod ◽  
Ad Libitum ◽  
Southern Flying Squirrel

Southern flying squirrels were housed in a simulated natural photoperiod for 40°N latitude and held at a constant temperature of 23 °C with food and water provided ad libitum. Body weight and reproductive condition were monitored weekly for 2 years. Males were in reproductive condition between January and mid-August and females were in estrus from late February to mid-April and again from mid-June until early August. Young were conceived during both estrous periods and several squirrels produced two litters in the same year. Minimum body weights were recorded in adults in mid-October each year. Pups born in the spring grew more rapidly than those from summer litters, and reached puberty at 2.5 months as compared with 6–8 months of age for the summer litters. Several seasonal rhythms appear to be controlled by photoperiod in this species.

Active calcium transport in the skin of the frog Rana pipiens: kinetics and seasonal rhythms.

1995 ◽  
Vol 198 (4) ◽  
pp. 967-974
Author(s):  
D F Stiffler
Keyword(s):  
Calcium Transport ◽  
Rana Pipiens ◽  
Dorsal Skin ◽  
Electrochemical Gradient ◽  
Fish Gill ◽  
Seasonal Rhythms ◽  
Active Calcium ◽  
Net Flux ◽  
Ventral Skin ◽  
Freshwater Environments

The frog Rana pipiens takes up Ca2+ against an electrochemical gradient from dilute external solutions that are similar to natural freshwater environments. The influx is dependent upon external [Ca2+] and is saturable. Kinetic analysis yielded a Km of 0.625 mmol l-1 and a Jmax of 38 nmol cm-2h-1. These kinetic variables suggest that both the affinity and capacity are smaller than those for Na+ and Cl- transport in the skin of the same species. They are also smaller than those for Ca2+ transport in fish gill. A significant portion (20-25%) of the Ca2+ entering a frog remains in Ca(2+)-rich layers of the skin, with ventral skin containing about three times as much Ca2+ as dorsal skin. There are seasonal rhythms in Ca2+ exchange: although Ca2+ influx does not vary significantly over the year, efflux is minimal in July, while net flux, which is negative most of the year, appears to be positive in July. Since these fluxes do not include dietary calcium, one cannot conclude that feeding frogs are in negative Ca2+ balance.

Role of melatonin on embryo viability in sheep

2019 ◽  
Vol 31 (1) ◽  
pp. 82 ◽  
Author(s):  
José-Alfonso Abecia ◽  
Fernando Forcada ◽  
María-Isabel Vázquez ◽  
Teresa Muiño-Blanco ◽  
José A. Cebrián-Pérez ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Corpus Luteum ◽  
Embryo Quality ◽  
Protective Action ◽  
Embryo Viability ◽  
Embryo Survival ◽  
Luteal Function ◽  
Seasonal Rhythms ◽  
Natural Hormone

Melatonin is a natural hormone synthesised in the pineal gland, the activity of which is regulated by day–night perception and dictates seasonal rhythms in reproduction in ovine species. Exogenous melatonin, administered via subcutaneous implants, is used to prolong the breeding season of ewes and can increase the proportion of pregnant ewes (fertility rate) and litter size. The increased proportion of ewes that become pregnant and the number of lambs born per lambing among melatonin-treated sheep may be caused by increased embryo survival, through enhanced luteal function, reduced antiluteolytic mechanisms, or improved embryo quality. This review focuses on the effects of melatonin on embryo viability and summarises the processes by which this hormone affects the ovary, follicle, oocyte, corpus luteum and embryo. Moreover, the effects of melatonin on the mechanisms of invivo maternal recognition of pregnancy in sheep and the protective action that it appears to have on the invitro procedures that are used to obtain healthy embryos are reviewed.

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