-Zebra Finches (Poephilu guttata) of arid Australia can breed continuously under favorable conditions. During droughts, however, breeding ceases but is said to begin again immediately after rain. We found that testis size in breeding birds did not change during, or between, reproductive cycles. Luteinizing hormone (irLH) levels in plasma, however, were significantly higher in males during early...

Flowering in many plants is strongly influenced by daylength. Arabidopsis thaliana FLOWERING LOCUS T (FT) encodes a small peptide that is now widely recognized as a major component of florigen, a systemic signal that induces flowering in response to daylength (Turck et al., 2008). FT is expressed in phloem companion cells, and the protein is translocated through the phloem to the shoot apical m...

BACKGROUND Many previous studies have documented seasonal variation in suicides globally. We re-assessed the seasonal variation of suicides in Finland and tried to relate it to the seasonal variation in daylength and ambient temperature and in the discrepancy between local time and solar time. METHODS The daily data of all suicides from 1969 to 2003 in Finland (N = 43,393) were available. The...

Time to maturity (TTM) is an important trait in soybean breeding programs. However, soybeans are a relatively new crop Africa. As such, TTM information for not yet as well defined other major producing areas. Multi-environment trials (METs) allow breeders analyze performance across diverse conditions, but also pose statistical challenges (e.g., unbalanced data). Modern methods, e.g., generalize...

“Environmental seasonality. . . a basic component of the ecosystem within which our ancestors evolved. . . left its mark indelibly upon the makeup of our biology and our behaviour.” ( Johnston, 1993) “the ability to perceive changes in daylength indicated by changes in the duration of melatonin secretion. . . is the only essential function attributable to melatonin in mammals to date.” (Arendt,...

Daylength controls flowering in many plant species. Early in the twentieth century, Garner and Allard (1920) first described the phenomenon of plants that flower only when daylength is longer or shorter than a particular threshold, named long-day and shortday plants, respectively. Rice is a shortday plant; flowering (termed “heading” in rice and other cereals) is promoted by short daylength. Ho...