Natural convection also plays a role in stellar physics.

Natural convection, or free convection, occurs due to temperature differences which affect the density, and thus relative buoyancy, of the fluid.

Natural convection can only occur, therefore, in a gravitational field.

Natural convection will be less likely and / or less rapid with more rapid diffusion ( thereby diffusing away the thermal gradient that is causing the convection ) and / or a more viscous ( sticky ) fluid.

Natural, biological insulators such as fur and feathers achieve similar effects by dramatically inhibiting convection of air or water near an animal's skin.

# REDIRECT Natural convection

Natural convection causing rising warm air and falling cooler air can result in an uneven stratification of heat.

* Natural ventilation can be created by providing vents in the upper level of a building to allow warm air to rise by convection and escape to the outside, while cooler air is drawn in through vents at the lower level.

Natural convection requires free flow of air over the heat sink.

Natural ventilation can be created by providing vents in the upper level of a building to allow warm air to rise by convection and escape to the outside.

Natural convection cooling an Earthship

Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic ( heritable ) basis of any phenotype which gives a reproductive advantage will become more common in a population ( see allele frequency ).

Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic ( heritable ) basis of any phenotype that gives a reproductive advantage will become more common in a population ( see allele frequency ).

Natural pearls will often show larger cavities where organic matter has dried out and decomposed.

Other QMS, e. g. Natural Step, focus on sustainability issues and assume that other quality problems will be reduced as result of the systematic thinking, transparency, documentation and diagnostic discipline that sustainability focus implies.

We will refer to any growth-related problem associated with natural resource abundance as the ‘ Natural Resource Curse .’

According to Dern, who ran twice as a Natural Law candidate for U. S. Senate and once for the Hartland Township Board of Trustees, the party will appear on the 2012 presidential ballot ticket In August 2012, the party nominated former Salt Lake City Mayor Rocky Anderson for president.

Natural fibers like manila, sisal, cotton and hemp will burn instead of melt.

Natural surface, single track trails will require some ongoing maintenance.

Natural triggers of avalanches include additional precipitation, rapid warming, rock fall, ice fall, and other impulse loads ; however, even when environmental conditions are consistent, the seasonal snowpack will evolve over time and develop stresses, often from the downslope creep of the snowpack.

9 ) If after reading it you die in the night, then it is as if you have died on ' Natural Deen ' and if you awake in the morning alive then you will have good fortune ".

Lieutenant Robert Peary brought six Inuit people from Greenland to the American Museum of Natural History in New York, at the request of the anthropologist Franz Boas, in order to " obtain leisurely certain information which will be of the greatest scientific importance " regarding Inuit culture.

In the Pre-Pyrenees, amongst other places of interest, visitors will find the Collegats-Terradets Territorial Park, the Boumort Natural Hunting Reserve and the Congost de Mont-rebei gorge.

The police are responsible for enforcing part I of the Wildlife and Countryside Act 1981, often advised by Natural England ( Natural England, 2007 ) and will investigate wildlife offences ; usually performed by Wildlife Crime Officers ( WCOs ).

However, according to the NAIRU, exploiting this short-run tradeoff will raise inflation expectations, shifting the short-run curve rightward to the " New Short-Run Phillips Curve " and moving the point of equilibrium from B to C. Thus the reduction in unemployment below the " Natural Rate " will be temporary, and lead only to higher inflation in the long run.

Natural predators — including various gull species, and both Red and Arctic Foxes, will take eggs and young.

In June 2010 the Forestry Commission North West England announced a three-year project that will see 90 Red Kites released in Grizedale Forest, Cumbria under a special licence issued by Natural England.

Natural killer cell activation is determined by the balance of inhibitory and activating receptor stimulation i. e. if the inhibitory receptor signaling is more prominent then NK cell activity will be inhibited, similarly if the activating signal if dominant then NK cell activation will result

Natural selection will only cause evolution if there is enough genetic variation in a population.

Natural selection acts on phenotypes, or the observable characteristics of organisms, but the genetically heritable basis of any phenotype which gives a reproductive advantage will become more common in a population ( see allele frequency ).

The university founded in 1796 through the will of Professor John Anderson, professor of Natural Philosophy at the University of Glasgow who left instructions and the majority of his estate to create a second university in Glasgow which would focus on " Useful Learning " – specialising in practical subjects – " for the good of mankind and the improvement of science, a place of useful learning ".

Natural gas public utility companies would be given the right of eminent domain, under a bill by Sen. Frank Owen 3, of El Paso, to acquire sites for underground storage reservoirs for gas.

Natural language expressions of algorithms tend to be verbose and ambiguous, and are rarely used for complex or technical algorithms.

" In addition to the various works of Brewster already mentioned, the following may be added: Notes and Introduction to Carlyle's translation of Legendre's Elements of Geometry ( 1824 ); Treatise on Optics ( 1831 ); Letters on Natural Magic, addressed to Sir Walter Scott ( 1832 ); The Martyrs of Science, or the Lives of Galileo, Tycho Brahe, and Kepler ( 1841 ); More Worlds than One ( 1854 ).

In its implications for deism, the Natural History of Religion ( 1757 ) may be Hume's most interesting work.

He had a small part in Oliver Stone's Natural Born Killers, playing a ranting inmate during a prison riot ; his part was eventually cut, but can be seen on the Special Edition DVD.

An exception is the 1789 publication Natural History of Selborne by Gilbert White ( 1720 – 1793 ), considered by some to be one of the earliest texts on ecology.

In Africa, if current trends of soil degradation continue, the continent might be able to feed just 25 % of its population by 2025, according to UNU's Ghana-based Institute for Natural Resources in Africa.

When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old.

# Thorn forest – Natural forests with > 30 % canopy cover, below altitude, in which the canopy is mainly composed of deciduous trees with thorns and succulent phanerophytes with thorns may be frequent.

Natural additives may be similarly harmful or be the cause of allergic reactions in certain individuals.

In David Hume's Dialogues Concerning Natural Religion, the character Cleanthes argues that no being could ever be proven to exist through an a priori demonstration:

Natural languages are spoken or signed, but any language can be encoded into secondary media using auditory, visual or tactile stimuli, for example in graphic writing, braille, or whistling.

Pliny the Elder's Natural History ( 36. 90 ) lists the legendary Smilis, reputed to be a contemporary of Daedalus, together with the historical mid-sixth-century BC architects and sculptors Rhoikos and Theodoros as two of the makers of the Lemnian labyrinth, which Andrew Stewart regards as " evidently a misunderstanding of the Samian temple's location en limnais the marsh '.

It now invites all interested people to attend a new conference to be held in the Natural History Museum Bern (" NHMB "), on September 10th from 18h15 till 20h15, on the theme " Searching for Life on Mars ".

Natural monopolies arise where the largest supplier in an industry, often the first supplier in a market, has an overwhelming cost advantage over other actual or potential competitors ; this tends to be the case in industries where fixed costs predominate, creating economies of scale that are large in relation to the size of the market, as is the case in water and electricity services.

Natural selection can act on any heritable phenotypic trait, and selective pressure can be produced by any aspect of the environment, including sexual selection and competition with members of the same or other species.

Natural numbers can be used for counting ( one apple, two apples, three apples, ...) from top to bottom.

* 1953 – The British Natural History Museum announces that the " Piltdown Man " skull, initially believed to be one of the most important fossilized hominid skulls ever found, is a hoax.

Natural language understanding involves the identification of the intended semantic from the multiple possible semantics which can be derived from a natural language expression which usually takes the form of organized notations of natural languages concepts.

Natural resources may be further classified in different ways.

Natural resources are materials and components ( something that can be used ) that can be found within the environment.

Some Natural resources can be found everywhere such as sunlight and air, when this is so the resource is known as an ubiquitous ( existing or being everywhere ) resource.

In 1969 the IUCN ( International Union for the Conservation of Nature and Natural Resources ) declared a national park to be a relatively large area with particular defining characteristics.