The color of amethyst has been demonstrated to result from substitution by irradiation of trivalent iron ( Fe < sup > 3 +</ sup >) for silicon in the structure, in the presence of trace elements of large ionic radius, and, to a certain extent, the amethyst color can naturally result from displacement of transition elements even if the iron concentration is low.

Inorganic qualitative analysis generally refers to a systematic scheme to confirm the presence of certain, usually aqueous, ions or elements by performing a series of reactions that eliminate ranges of possibilities and then confirms suspected ions with a confirming test.

Due to the blocking presence of successive mountain ranges, the Interior of the province has a semi-arid climate with certain locations receiving less than 250 mm ( 10 ") in annual precipitation.

For example, in the presence of H < sub > 2 </ sub > O < sub > 2 </ sub > formed by the eosinophil, and either chloride or bromide ions, eosinophil peroxidase provides a potent mechanism by which eosinophils kill multicellular parasites ( such as, for example, the nematode worms involved in filariasis ); and also certain bacteria ( such as tuberculosis bacteria ).

These depend on both the presence and duration of certain signs and symptoms.

A Venerable has as of yet no feast day, no churches may be built in his or her honor, and the church has made no statement on the person's probable or certain presence in heaven, but prayer cards and other materials may be printed to encourage the faithful to pray for a miracle wrought by his or her intercession as a sign of God's will that the person be canonized.

There is ample evidence that the intense radiation emitted by certain kinds of astronomical objects is due to black holes ; for example, microquasars and active galactic nuclei result from the presence of stellar black holes and black holes of a much more massive type, respectively.

Liquid crystals find wide use in liquid crystal displays, which rely on the optical properties of certain liquid crystalline substances in the presence or absence of an electric field.

However, in certain axiom systems for constructive set theory, the axiom of choice does imply the law of the excluded middle ( in the presence of other axioms ), as shown by the Diaconescu-Goodman-Myhill theorem.

The presence of pain in an animal cannot be known for certain, but it can be inferred through physical and behavioral reactions.

Opioids and opiate receptors occur naturally in crustaceans and, although at present no certain conclusion can be drawn, their presence indicates that lobsters may be able to experience pain.

The Pauli effect is a term referring to the apparently mysterious ' anecdotal ' failure of technical equipment in the presence of certain people.

Although French geologists already in 1926 established for certain the presence of oil and gas in the country only then France started exploiting these reserves.

Another concept utilised in structual anthropology came from the Prague school of linguistics, where Roman Jakobson and others analyzed sounds based on the presence or absence of certain features ( such as voiceless vs. voiced ).

", and responds by saying that in the symbolic infrastructure of some religions, there is the image of a certain extraordinary spiritual king's " miraculous powers ", to whom frequently a certain moral presence is attributed.

Scorpions are also known to glow when exposed to certain wavelengths of ultraviolet light such as that produced by a black light, due to the presence of fluorescent chemicals in the cuticle.

In certain jurisdictions, such as New Jersey, the EPROM has a tamper-evident seal and can only be changed in the presence of Gaming Control Board officials.

Like other orchids ' seeds, vanilla seeds will not germinate without the presence of certain mycorrhizal fungi.

For example, Rae points out that the statisticians are right to criticise Victorian compilers for " including minor matches to enable Grace to reach certain milestones "; but he also respects the view of Grace's contemporaries that " any match in which he played was elevated in status by his very presence ".

The presence of certain versions of wheat genes has been important for crop yields.

The correlation between damage to certain specific brain areas ( usually in the left hemisphere ) and the development of specific types of aphasia makes it possible to deduce ( albeit very roughly ) the location of a suspected brain lesion based only on the presence ( and severity ) of a certain type of aphasia, though this is complicated by the possibility that a patient may have damage to a number of brain areas and may exhibit symptoms of more than one type of aphasia.

There are numerous qualitative chemical tests, for example, the acid test for gold and the Kastle-Meyer test for the presence of blood.

Cooking can also occur through chemical reactions without the presence of heat, most notably as in Ceviche, a traditional South American dish where fish is cooked with the acids in lemon or lime juice.

The study was the first nationwide analysis measuring the presence of the chemical in U. S. water systems.

In the 1880s, Wilhelm Ostwald at Leipzig University started a systematic investigation into reactions that were catalyzed by the presence of acids and bases, and found that chemical reactions occur at finite rates and that these rates can be used to determine the strengths of acids and bases.

They share many similarities with the higher plants, including the presence of asymmetrical flagellated cells, the breakdown of the nuclear envelope at mitosis, and the presence of phytochromes, flavonoids, and the chemical precursors to the cuticle.

In the presence of a chemical gradient bacteria will chemotax, or direct their overall motion based on the gradient.

Conversely, factors that favor plate columns are: presence of solids in feed, high liquid rates, large column diameters, complex columns, columns with wide feed composition variation, columns with a chemical reaction, absorption columns, columns limited by foundation weight tolerance, low liquid rate, large turn-down ratio and those processes subject to process surges.

* Chemical diffusion occurs in a presence of concentration ( or chemical potential ) gradient and it results in net transport of mass.

* In chemical nomenclature, the prefix " hydroxy -" shows the presence of a hydroxyl functional group (- OH )

In glasses ( solids that exist in a vitreous disordered state ), atoms may also be held together by chemical bonds without presence of any definable molecule, but also without any of the regularity of repeating units that characterises crystals.

These works postulated the presence of chemical signals and physico-chemical processes such as diffusion, activation, and deactivation in cellular and organismic growth.

There are significant differences in the survival of archaeological material depending on whether a site is wet or dry, on the nature of the chemical environment, on the presence of biological organisms and on the dynamic forces present.

Little is known about the element but limited chemical experiments have shown that it forms a stable divalent ion in solution as well as the predicted trivalent ion that is associated with its presence as one of the actinides.

The presence of such a gap suggested communication via chemical messengers traversing the synaptic cleft, and in 1921 German pharmacologist Otto Loewi ( 1873 – 1961 ) confirmed that neurons can communicate by releasing chemicals.

It is not affected by external factors such as temperature, pressure, chemical environment, or presence of a magnetic or electric field.

The presence of such a TE provides a straightforward means of identifying the mutant allele, relative to chemical mutagenesis methods.

No firm evidence of the presence of water, organic matter or other chemical compounds on their surfaces has been obtained.

These secondary peaks, not to be confused with high energy satellites which are discussed later, arise from the presence of the same element in multiple different chemical states on a surface ( i. e. Adsorbate layers ) or from relaxation transitions involving valence band electrons of the substrate.

The presence of satellites can distort the true Auger peak and / or small peak shift information due to chemical bonding at the surface.

As a gas is heated, electrons begin to leave the atoms, resulting in the presence of free electrons, which are not bound to nuclei, and ions, which are chemical species that contain unequal number of electrons and protons, and therefore possess an electrical charge.

A number of factors can influence its efficacy, including chemical composition of the stone, presence of anomalous renal anatomy and the specific location of the stone within the kidney, presence of hydronephrosis, body mass index, and distance of the stone from the surface of the skin.

This is triggered by the presence of a chemical produced by the females, bonellin.