Endogenous daily (circadian) rhythms allow organisms to anticipate daily changes in the environment. Most mammals are specialized to be active during the night (nocturnal) or day (diurnal). However, typically nocturnal mammals become diurnal when energetically challenged by cold or hunger. The circadian thermo-energetics (CTE) hypothesis predicts that diurnal activity patterns reduce daily ener...

Recurrent and intermittent nocturnal hypoxia is characteristic of several diseases including chronic obstructive pulmonary disease, congestive heart failure, obesity-hypoventilation syndrome, and obstructive sleep apnea. The contribution of hypoxia to cardiovascular morbidity and mortality in these disease states is unclear, however. To investigate the impact of recurrent nocturnal hypoxia on h...

A study was carried out to investigate whether an imbalance in the autonomic nervous system or release of histamine, or both, is responsible for the nocturnal increase in airflow obstruction in asthmatic children. The study comprised 18 children with allergic asthma, nine with (group 1) and nine without (group 2) nocturnal airflow obstruction, and an age matched control group. All drugs were wi...

It has been demonstrated that type II iodothyronine deiodinase is present in rat pineal gland, and the deiodinase activity markedly increases during the hours of darkness, primarily through beta-adrenergic mechanism. We have studied the relationship between pineal type II iodothyronine deiodinase messenger RNA (mRNA) and the deiodinase activity to elucidate the mechanisms involved in the noctur...

abstract  introduction: hypertension is a very common cardiovascular disease with extensive effects on body organs. this study was conducted to compare the extent of target organ damage in hypertensive patients with and without significant nocturnal fall in blood pressure (dippers and non-dippers, respectively). methods: one-hundred patients with recently diagnosed hypertension underwent 24-hou...

In recent years the phenomenon of 24 hr. periodicity in animals has attracted considerable attention. Diurnal rhythms have been reviewed by Welsh (1938), Park (1940) and Calhoun (1944), and present many interesting physiological and ecological problems. It is evident that they are common and manifest in diverse ways. Park, Lockett & Myers (1931), in a short study of nocturnal ecology among fore...

The natural distribution and the species ecology of lesser-known nocturnal endemic brown palm civet in Western Ghats are definite. We used camera trap data from to predict suitable niche, coat colour pattern, diel activity. environmental variables like rainfall, elevation, isothermaility, tree density, height profoundly influence civet’s habitat suitability. determined that most area entire is ...

s/esr/v3/n2/p239-247>. This study describes the activity pattern of the blue-eyed black lemur Eulemur macaco flavifrons for the firsttime and investigates the parameters, such as season orhabitat, that may influence the distribution of activity overthe 24 h cycle. Four groups of E. m. flavifrons in 2 forestfragments with different degrees of degradation were fol-lowed fo...