modification


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Related to modification: behavior modification

modification

[‚mäd·ə·fə′kā·shən]
(cell and molecular biology)
In nucleic acid metabolism, any changes made to deoxyribonucleic acid or ribonucleic acid after their original incorporation into a polynucleotide chain.
(engineering)
A major or minor change in the design of an item, effected in order to correct a deficiency, to facilitate production, or to improve operational effectiveness.
(metallurgy)
Treatment of molten aluminum alloys containing 8-13% silicon with small amounts of a sodium fluoride or sodium chloride mixture; improves mechanical properties.
(science and technology)
Any change brought about by external or internal factors.

Modification

 

in biology, nonhereditary changes in the visible characters (phenotype) of an organism; these changes occur under the influence of altered environmental conditions.

Modifying factors in the environment (temperature, illumination, diet) act on the organism during sensitive periods of its development, precipitating changes in the organism’s internal makeup (for example, changes in hormone level) and altering the course of ontogeny. Modificational variation consists in changes within the limits of the genotypically conditioned norm of reaction. Depending on the temperature of its environment, the Himalayan rabbit may change from black in cold weather to rusty brown in mild temperatures to pure white in high temperatures. However, the coloration of the parent rabbits is not inherited by their young; only the capacity to change color according to temperature change is inherited.

In nature, modifications are, as a rule, adaptive reactions of organisms to environmental factors. Thus, in lake Sagittaria sagittifolia, the shape of the leaves depends on where they grow: the above-water leaves are arrow-shaped, the leaves that float are heart-shaped with stomata on the upper side, and the underwater leaves are ribbon-like. Nonadaptive modifications often consist of all kinds of developmental disturbances, the extreme expression of which includes deformities and morphological and physiological malfunctions. These modifications occur, as a rule, in response to strong external stimuli, to which individuals of a given species are rarely exposed under normal conditions.

In contrast to mutations, modifications are not transmitted by heredity. Modifications develop in individuals of a given generation only when the conditions under which these modifications normally arise are present. However, in unicellular and occasionally multicellular organisms, prolonged modifications are found when changes in visible characters that have arisen as a result of environmental factors are retained for several generations, even after the disappearance of the inducing factors. This type of modification is apparently caused by changes in relatively stable self-reproducing cytoplasmic structures. Since they are nonhereditary, modifications have no direct evolutionary significance. If, however, a phenotype formed as a result of modification has a high adaptive value, the phenotype may become fixed in evolution only through the selection of those mutants that retain a given modification, but discard other modifications of a given character.

REFERENCES

Lobashev, M. E. Genetika, 2nd ed. Leningrad, 1967.
Shmal’gauzen, I. I. Faktory evoliutsii. Moscow, 1968.

N. V. TIMOFEEV-RESOVSKII, V. I. IVANOV and V. A. MGLINETS

modification

1. A written amendment to the contract document signed by both parties.
3. A written or graphic interpretation issued by the architect.
4. A written order for a minor change in the work, 1 issued by the architect.

modification

An alteration or change meant to rectify faults or shortcomings or which offers improved capability. A modification involves changes in the design of equipment or components.
References in periodicals archive ?
Services include equipment and graphics installation, pre-delivery inspections, cab modifications and custom vehicle modifications.
Citation: Yang Wang et al.,"N6-methyladenosine RNA modification regulates embryonic neural stem cell self-renewal through histone modifications," Nature Neuroscience 2018; DOI: 10.1038/s41593-017-0057-1
where [r.sub.a] is the addendum circle radius, l represents the profile modification length, [l.sub.ki] is the modification length of point [P.sub.ki], aa is the pressure angle of addendum circle, and zk represents the coordinate of the Z axis.
"It's a way to discover nucleic acid modifications that you didn't know existed," says Peter Dedon, the Underwood-Prescott Professor of Biological Engineering at MIT.
At this point, sum of modification is [e.sub.i] (including tooth profile and tooth pitch deviation) and integrated deformation is [[delta].sub.i] (the deformation quantity of engagement teeth in the direction of the meshing line):
He said: "Speeding is the most attractive part of modifications for youngsters.
Because the department received "a considerable amount of comments both in support and in opposition" to the modification request, NMED Secretary-Designate Ryan Flynn determined that the issue has generated significant public interest and that the permit modification request should be subject to the Class 3 process to allow "for a more extensive review...(and) additional time for the submittal and consideration of comments by the public."
Vallaro's website, official911.org is a repository of information pertaining to loan modifications, short sales and other foreclosure relief options.
However, lenders like Bank of America who, as of the June s Home Affordable Modification Program report had an estimated 469,905 homeowners who were delinquent on their home loan and potentially qualified for a home loan modification.
Bank of America Corp (NYSE: BAC) has announced that it has completed 160,000 mortgage modifications in the first half of 2010.
Mulligan finds that the income target and collateral value tests combine to "create a tradeoff between the number of foreclosures prevented in the short term and the durability of foreclosure prevention efforts, because they make it impossible to both write down principal and offer modification to a wide range of borrowers." Another consequence of this tradeoff, he continues, "is to reduce collections, increase foreclosures and their costs, and reduce efficiency as compared to alternative means tested mortgage modification rules."
But he was not offered the permanent modification he'd been hoping for.

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