Numerous melanocortin, MCH and melatonin receptors have been identified in fish and frogs, including a homologue of MC1R, a melanocortin receptor known to regulate skin and hair colour in humans.

No food has been found to elevate plasma melatonin levels in humans.

In animals including humans the profile of melatonin synthesis and secretion is affected by the variable duration of night in summer as compared to winter.

In humans, 90 % of melatonin is cleared in a single passage through the liver, a small amount is excreted in urine, and a small amount is found in saliva.

When used several hours before sleep according to the phase response curve for melatonin in humans, small amounts of melatonin shift the circadian clock earlier, thus promoting earlier sleep onset and morning awakening.

A very small dose taken several hours before bedtime in accordance with the phase response curve for melatonin in humans ( PRC ) doesn't cause sleepiness but, acting as a chronobiotic ( affecting aspects of biological time structure ), advances the phase slightly and is additive to the effect of using light therapy upon awakening.

Concentration of melatonin in the bile is 2 – 3 times higher than the otherwise very low daytime melatonin levels in the blood across many diurnal mammals, including humans.

Its primary hormone is melatonin, which influences daily rhythms and may have an antigonadotropic effect in humans.

The fire ant is thought to infest approximately two million acres of land in Georgia, attacking crops, young wildlife and livestock and can be a serious health menace to humans who are allergic to its venom, Blasingame said.

`` This is a long picture and a controversial one, but basically it is a moral, enthralling and heartbreaking description of humans who have become unlinked from life as perhaps Rome has from her traditional political, cultural and religious glories ''.

Even a nuclear holocaust is a little less frightful to contemplate than a race of dehumanised humans occupying the earth until doomsday ''.

Helping behavior is seen in humans at about two years old, when a toddler is capable of understanding subtle emotional cues.

A related concept in descriptive ethics is psychological egoism, the thesis that humans always act in their own self-interest and that true altruism is impossible.

The pineal body, known to regulate sleep patterns in humans, is thought to produce the hormones involved in hibernation and aestivation in amphibians.

In some fictional works, the difference between a robot and android is only their appearance, with androids being made to look like humans on the outside but with robot-like internal mechanics.

But humans can do something equally useful, in the case of certain enumerably infinite sets: They can give explicit instructions for determining the nth member of the set, for arbitrary finite n. Such instructions are to be given quite explicitly, in a form in which they could be followed by a computing machine, or by a human who is capable of carrying out only very elementary operations on symbols.

Eastern Anatolia, along side Mesopotamia and the Levant, is also a heart region for the Neolithic revolution, one of the earliest areas in which humans domesticated plants and animals.

Rieux reflects on the epidemic and reaches the conclusion that there is more to admire than to despise in humans.

It is arbitrary and capricious, and it leaves humans in a state of fear and uncertainty, which ends only in death.

Environmental ethics is concerned with questions such as the duties of humans towards landscapes or species.

Eventually, humans learned to smelt metals such as copper and tin from ore, and, around 2500 BC, began alloying the two metals to form bronze, which is much harder than its ingredients.

The thick inner layer of the shell is composed of nacre or mother-of-pearl, which in many species is highly iridescent, giving rise to a range of strong and changeable colors, which make the shells attractive to humans as decorative objects, and as a source of colorful mother-of-pearl.

Abalone have long been a valuable food source for humans in every area of the world where a species is abundant.

It may be an exaggerated form of an instinctive response that helped early humans to survive, or a cultural phenomenon that is most common in predominantly European societies.

Spiders, for instance, being relatively small, don ’ t fit the usual criterion for a threat in the animal kingdom where size is a factor, but nearly all species are venomous, and although rarely dangerous to humans, some species are dangerous.

Animism encompasses the beliefs that there is no separation between the spiritual and physical ( or material ) world, and souls or spirits exist, not only in humans, but also in all other animals, plants, rocks, geographic features such as mountains or rivers, or other entities of the natural environment.

The reported output from global aquaculture operations would supply one half of the fish and shellfish that is directly consumed by humans ; however, there are issues about the reliability of the reported figures.

* 1932 – A vaccine for yellow fever is announced for use on humans.

Hume concludes that there is an innate faculty of instincts which both beasts and humans share, namely, the ability to reason experimentally ( through custom ).

Ethanol has been produced and consumed by humans for millennia, in the form of fermented and distilled alcoholic beverages.

Benzodiazepines share a similar chemical structure, and their effects in humans are mainly produced by the allosteric modification of a specific kind of neurotransmitter receptor, the GABA < sub > A </ sub > receptor, which increases the conductance of this inhibitory channel ; this results in the various therapeutic effects as well as adverse effects of benzodiazepines.

It refers to machines, roads, factories, schools, infrastructure, and office buildings which humans have produced in order to produce goods and services.

Singer argues there is no evidence that the increases in carbon dioxide produced by humans cause global warming, and that if temperatures do rise it will be good for humankind.

Marx believed that capitalism was exploiting humans ; that the objects produced by laborers became alienated and thus ultimately dehumanized them to functional objects.

Some are produced by the human body with adequate precursors ( glutathione, Vitamin C ), and those the body cannot produce may only be obtained in the diet via direct sources ( Vitamin C in humans, Vitamin A, Vitamin K ) or produced by the body from other compounds ( Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight ).

Typically, PostScript programs are not produced by humans, but by other programs.

In healthy humans, the p53 protein is continually produced and degraded in the cell.

Coastal water pollution produced by humans and systematic increase in sea water temperature have also been implicated as contributing factors in red tides.

A cosmodicy attempts to justify the fundamental goodness of the universe in the face of evil, and an anthropodicy attempts to justify the fundamental goodness of human nature in the face of the evils produced by humans.

* The hermaphrodite humans of Gethen may have been produced as an adaptation to a harsh climate, or an experiment to see how people would live without gender.

Xenophon's Memorabilia poses the argument that all animals are " only produced and nourished for the sake of humans ".

The gene MC1R is primarily responsible for determining whether pheomelanin and eumelanin is produced in humans.

This second concept is reminiscent of the social constructivist approach, which holds that mathematics is produced by humans rather than being " discovered " from abstract, a priori truths.

Infectious CTXφ particles are produced when V. cholerae infects humans.

# Intestinal bloating – most intestinal gas is produced from carbohydrates in the diet, mostly those that humans cannot digest and absorb.

* Melanocyte-stimulating hormone ( MSH ) ( not produced in humans )

Some blind humans have learned to find their way using clicks produced by mouth or mechanically ( see Human echolocation ).

According to Ovid, in the formative years of growth after the deluge, mother earth accidentally produced a gigantic Python that terrorized the humans.

This materialist perspective informs scientific methodology, insofar as that methodology assumes that humans have no access to omniscience and that therefore human knowledge is an ongoing, collective enterprise that is best produced via scientific and logical conventions adjusted specifically for material human capacities and limitations.

Other kinds such as pearl oysters, generally not eaten by humans, are harvested for the pearl produced within the mantle.

In Canada all products with a label containing the words pepper spray, mace, etc., or otherwise originally produced for use on humans are classified as a prohibited weapon.

Somatotropin ( STH ) refers to the growth hormone 1 produced naturally in animals, whereas the term somatropin refers to growth hormone produced by recombinant DNA technology, and is abbreviated " HGH " in humans.