The eggcell or oosphere is a large cell containing a single large nucleus , and in the green plants the rudiments of plastids. They are more easily seen, when the nucleus is about to undergo mitosis, at the ends of the spindle, where they form the centres towards which the radiating fibres in. In the spermatozoids of Chara, Vascular Cryptogams, and in those of Cycas, Zamia and Ginkgo, the cilia arise from a centrosome-like body which is found on one side of the nucleus of the spermatozoid mother-cell.
The latter are vacuolated, and contain each a nucleus and several dark granules. Had his successor been as prudent and able, he might have made a unified Netherlands the nucleus of a mighty middle kingdom, interposing between France and Germany, and a revival of that of the Carolingian Lothaire.
In these latter cases the reaction may proceed in different directions; thus, with the aromatic hydrocarbons, chlorine in the cold or in the presence of a carrier substitutes in the benzene nucleus , but in the presence of sunlight or on warming, substitution takes place in the side chain. In young cells the chromatophores are small, colorless, highly refractive bodies, principally located around the nucleus.
Albumen crystals are also to be found in the cytoplasm, in leucoplasts and rarely in the nucleus. In plants with multinucleate cells, such as Albugo, Peronospora and Vaucheria, it is usually a uninucleate cell differentiated by separation of the nuclei from a multinucleate cell, but in Albugo bliti it is multinucleate, and in Sphaero plea it may contain more than one nucleus.
The principality which was to become the nucleus of the future Russian empire was not Novgorod with its democratic institutions, but its eastern neighbour Moscow, in which the popular assembly played a very insignificant part, and the supreme law was the will of the prince. This compound is readily oxidized to benzoic acid, C 6 H 5 H, the aromatic residue being unattacked; nitric and sulphuric acids produce nitro-toluenes, C6H4 CH3 N02j and toluene sulphonic acids, C 6 H 4 CH 3 SO 3 H; chlorination may result in the formation of derivatives substituted either in the aromatic nucleus or in the side chain; the former substitution occurs most readily, chlor-toluenes, C 6 H 4 CH 3 Cl, being formed, while the latter, which needs an elevation in temperature or other auxiliary, yields benzyl chloride, C 6 H 5 CH 2 C1, and benzal chloride, C 6 11 5 CHC1 2.
Another Roman basilica forms the nucleus of the cathedral. The problem is a very difficult one and cannot be regarded as definitely settled, but it is difficult to understand why all this additional complexity in the division of the nucleus should be necessary if the final result is only a quantitative separation of the chromatin. The researches of the last twenty years have shown that the structure of the nucleus and the phenomena of nuclear division in these lower forms conforms in all essential details to those in the higher plants.
The central body probably plays the part of a nucleus and some observers consider that it has the characters of a typical nucleus with mitotic division. The bacteria, in most cases, have no definite nucleus or central body.
The chromatin is distributed throughout the cytoplasm in the form of granules which may be regarded as a distributed nucleus corresponding to what Hertwig has designated, in protozoa, chromidia.
Some observers consider that the yeast nucleus possesses a typical nuclear structure, and exhibits division by mitosis, but the evidence for this is not very satisfactory. Hantzsch Ber. The so-called "beetle-stones" of the coal-formation of Newhaven, near Leith, which have mostly a coprolite nucleus , have been applied to various ornamental purposes by lapidaries.
The red blood-corpuscles are invariably oval disks, with a central nucleus which causes a slight swelling; hence they are oval and biconvex. But this very development of Mosaism implies the existence of an original nucleus or substratum, although the recovery of its precise extent is very difficult.
The nucleus of the invading horde was a small pastoral tribe in Mongolia, the chief of which, known subsequently to Europe as Jenghiz Khan, became a mighty conqueror and created a vast empire stretching from China, across northern and central Asia, to the shores of the Baltic and the valley of the Danube - a heterogeneous state containing many nationalities held together by purely administrative ties and by an enormous military force.
The talismanic name Immanuel became the nucleus out of which the later Messianic prophecies of Isaiah grew. There are other nebulae in which a nucleus can be just discerned, others again in which the nucleus is easily seen, and still others where the nucleus is a brilliant star-like point. By the nucleus of such an institute was formed round Dominic and was known as the "Holy Preaching. As a result of this backward projection of later conceptions, the recovery of the true historical nucleus is difficult.
Below it are covered promenades, and from it steps descend to the lower town, the oldest part of which the so-called Marina , sloping gradually towards the sea, is probably the nucleus of the Roman municipium, while the quarter of Stampace lies to the west, and beyond it again the suburb of Sant' Avendrace.
This forms the nucleus of the adult shell, and, as the animal grows, becomes enclosed by a reflection of the mantle-skirt. Cephalic shield pointed behind; shell internal, chiefly membranous, with calcified nucleus , nautiloid; parapodia forming fins.
In Clausilia, according to the observations of C. Gegenbaur, the primitive shell-sac does not flatten out and disappear, but takes the form of a flattened closed sac. Within this closed sac a plate of calcareous matter is developed, and after a time the upper wall of the sac disappears, and the calcareous plate continues to grow as the nucleus of the permanent shell.
But it is equally plain that the Ophite nucleus has from time to time received very numerous and often curiously perverted accretions from Babylonian Judaism, Oriental Christianity and Parsism, exhibiting a striking example of religious syncretism.
In the eighteenth chapter he records his intention of founding a hall at Oxford, and in connexion with it a library of which his books were to form the nucleus. The two nuclei are successively divided from the egg nucleus in the usual way, but they frequently become absorbed in the peripheral protoplasm instead of being extruded from the egg-cell altogether.
Petrunkevich , the second polar nucleus uniting with one daughter- nucleus of the first polar body gives rise to the germ-cells of the parthenogenetically-produced male. The segmentation of the fertilized nucleus results in the formation of a number of nuclei which arrange themselves around the periphery of the egg and, the protoplasm surrounding them becoming constricted, a blastoderm or layer of cells, enclosing the central yolk, is formed.
In the egg of these insects a small number of nuclei are formed by the division of the nucleus , and each of these nuclei originates by division the cell-layers of a separate embryo. The earliest churches were built with cemeteries for the dead; and thus we find the nucleus of the city of Venice, little isolated groups of dwellings each on its separate islet, scattered, as Cassiodorus 1 says, like sea-birds' nests over the face of the waters. After the fall of the Roman empire, it was the nucleus of the kingdom of Carentania, which was founded by Samo, a Frankish adventurer, but soon fell to pieces after his death.
From to he arranged gifts from France to American libraries aggregating 30, volumes, and a gift of 50 volumes by the city of Paris in reciprocated in with more than volumes contributed by private citizens was the nucleus of the Boston public library.
In Polia the connective tissue enclosed in the external muscular layer is eminently vacuolar - all the intermediate stages between such cells in which the vacuole predominates and the nucleus is peripheral and those in which the granular protoplasm still entirely fills them being moreover present. His personality drew a number of strong men after him, and a society meeting held in a kitchen and then in a warehouse became the nucleus of a circuit, a chapel being built at Tunstall in July , two months after the fusion of the Bourne and Clowes forces.
Dumas went no further that thus epitomizing his observations; and the next development was made in by Auguste Laurent, who, having amplified and discussed the applicability of Dumas' views, promulgated his Nucleus Theory, which assumed the existence of " original nuclei or radicals " radicaux or noyaux fondamentaux composed of carbon and hydrogen, and " derived nuclei " radicaux or noyaux derives formed from the original nuclei by the substitution of hydrogen or the addition of other elements, and having properties closely related to the primary nuclei.
The introduction of hydroxyl groups into the benzene nucleus gives rise to compounds generically named phenols, which, although resembling the aliphatic alcohols in their origin, differ from these substances in their increased chemical activity and acid nature.
These observations may be summarized by saying that the benzene nucleus is more negative in character than the aliphatic residues. Generally if any group be replaced by another group, then the second group enters the nucleus in the position occupied by the displaced group; this means that if we can definitely orientate three di-derivatives of benzene, then any other compound, which can be obtained from or converted into one of our typical derivatives, may be definitely orientated.
If we accept Kekule's formula for the benzene nucleus , then we may expect the double linkages to be opened up partially, either by oxidation or reduction, with the formation of di-, tetra-, or hexa-hydro derivatives, or entirely, with the production of open chain compounds. Decompositions of this nature were first discovered in the naphthalene series, where it was found that derivatives of indene and of hydrindene and indone and also of benzene resulted; Zincke then extended his methods to the disintegration of the oxybenzenes and obtained analogous results, R-pentene and aliphatic derivatives being formed Rsymbolizing a ringed nucleus.
Such condensed nuclei are, in many cases, more readily obtained than the parent nucleus. It consists in an unequal number of chromosomes passing over to each of the daughter nuclei, so that one may become hypochromatic, the other hyperchromatic.
When this happens the resulting cleavage of the cytoplasm and nucleus is also unequal. Pigmented cell with resting nucleus. The nucleolus is elongated, and its longest measurement lies in the direction of the equatorial plane of the nucleus. In the earlier accepted notion of direct segmentation, usually known as the schema of Remak, division was described as commencing in the nucleolus, as thereafter spreading to the nucleus , and as ultimately implicating the cell-substance.
Oertel thinks that in man we have these two different functions carried on by the one nucleus containing both chromatin orders. The liver cells are seen to contain a large globule of fat which pushes the cell nucleus to one side - giving the signet-ring appearance.
This very likely formed the nucleus of a book which bore the name of that sheik and was much read in the 3rd century from the Flight.
Even the isolated cells of the yeast plant have each one nucleus. In young asci a similar fusion of two nuclei occurs, and also in basidia, in each case the nucleus of the ascus or of the basidium resulting from the fusion subsequently giving rise by division to the nuclei of the ascospores and basidiospores respectively. The contents of the antheridium are not set free, but that organ penetrates the oogonium by means of a narrow outgrowth, the fertilizing tube, and a male nucleus then passes over into the single oosphere, which at first multinucleate becomes uninucleate before fertilization.
In the development of the ascus we find two nuclei at the base which fuse together to form the single nucleus of the young ascus. The nucleus of the county consisted of the lands of Cromarty in the north of the peninsula of the Black Isle. The analogy of the French epic, the Chanson de Roland, favours the belief that there was some nucleus of fact. But we have first to consider whether any of the accounts come to us on such evidence that we are bound to consider them as containing a nucleus of truth.
But the original nucleus and parts of the incidents may be the work of a single great poet, and yet other episodes may be of different authorship, wrought into the structure of the poem in later times. Kirchhoff of Berlin. Their territories are in many cases neither compact nor continuous, consisting of a number of villages here and there, with a nucleus of more or less importance round the chief town.
As the great aim of this side of public activity is to secure funds for the maintenance of the state's life and working, the administration which operates for this end is the true nucleus of all national finance. A special literature of oracles did indeed arise; the divine words were collected and the circumstances which produced them were recorded; and had Delphi become in fact the centre of Greece, as Plato conceived it, here might have been the nucleus of a scripture.
There are three main divisions, Staden, the ancient nucleus of the city, properly confined to Stadholmen the city island which divides the stream from Molar into two arms, Norrstrom and Soderstrom; Norrmalm on the north shore of the channel, and Sodermalm on the south.
Its nucleus was a castle, built in by Egbert, one of Charlemagne's counts, against the Danes. Blom found that on brominating orthoacetamido-acetophenone in presence of water or acetic acid, the bromine goes into the benzene nucleus , whilst in chloroform or sulphuric acid or by use of bromine vapour it goes into the side chain as well.
The may also contain an active galactic nucleus at their center. These are all regulated from an area of the brain called the suprachiasmatic nucleus , which is in the hypothalamus. The wall of the nucleus breaks down, and the cytoplasmic spindle-fibres become mixed with those derived from the nuclear network.
The benzene nucleus presents a remarkable case, which must be considered in the formulation of any complete theory of valency. Formula 4 is symmetrical and based on Kekule's formula: it is in full accord with the syntheses and decompositions of the naphthalene nucleus and the number of isomers found.
This is obviously unsymmetrical, consisting of an aliphatic and an aromatic nucleus ; Claus explained the formation of the same phthalic acid from the oxidation of either nucleus by supposing that if the aromatic group be oxidized, the aliphatic residue assumes the character of a benzene nucleus.
By reduction, the double linkages become saturated, and compounds result which stand in much about the same relation to the original nucleus as hexamethylene does to benzene.
Thus ortho-phenylene diamine yields the following products: N H N. The fifth compound, on the other hand, does not behave as an unsaturated aliphatic compound, but its deportment is that of a nucleus , many substitution derivatives being capable of synthesis. This is comparable with the reduction of the benzene nucleus into hexamethylene, a substance of an aliphatic character. Naphthyridines and naphthinolines result from the condensation of two pryridine and two quinoline nuclei respectively; and quino-quinolines are unsymmetrical naphthyridine nuclei condensed with a benzene nucleus.
The city is built upon the lower slope of the Serra do Ouro Preto, a spur of the Espinhago, deeply cut by ravines and divided into a number of irregular hills, up which the narrow, crooked streets are built and upon which groups of low, old-fashioned houses form each a separate nucleus. In a number of people in Westmorland and north Lancashire who had separated from the common national worship,' came under the influence of Fox, and it was this community if it can be so called at Preston Patrick which formed the nucleus of the Quaker church.
Railway concessions were given to Germans over the heads of British applicants already in possession of lines from which they were expro- Activity priated, thus affording the nucleus of the Bagdad Turkey. When heated with the halogens, acetophenone is substituted in the aliphatic portion of the nucleus ; thus bromine gives phenacyl bromide, C6H6CO. The nucleus of the stronghold is a donjon over ft.
The original archduchy, which included Upper Austria, is the nucleus of the Austrian empire, and the oldest possession of the house of Habsburg in its present dominions. The question whether a corpuscle actually has a material gravitating nucleus is undecided, but there are strong reasons for believing that its mass is entirely due to the electric charge.
It was named Sao Paulo, and has been at once the source whence knowledge and civilization have been diffused through Brazil, and the nucleus of a colony of its manliest and hardiest citizens, which sent out successive swarms of hardy adventurers to people the interior.
It is probable that the Ottadeni built a fort or camp on the rock on which Edinburgh Castle now stands, which was thus the nucleus around which, in course of time, grew a considerable village. Substitution takes place usually in the nucleus and only rarely in the side chain, and according to the conditions of the experiment and the nature of the compound acted upon, one or more nitro groups enter the molecule.
The nucleus of the new army he found in the Czech mercenaries, seasoned veterans who readily transferred their services to the best payer.
Towards the second half of the 2nd century B. Perhaps those which were to be sung according to the old Davidic mode formed the nucleus of the collection, and to these were added other poems to be sung according to the more intricate Korahite and Asaphic modes. The building of the National Portrait Gallery, adjoining it, dates from , but the nucleus of the collection was formed in The third natural division of Burma is the old province of Tenasserim, which, constituted in with Moulmein as its capital, formed the nucleus from which the British supremacy throughout Burma has grown.
This formed the nucleus of his future army. Those substituted in the benzene nucleus are obtained by condensing two molecules of a substituted benzyl and benzal chlorides. The kingship formed the nucleus of new governments as the feudal system passed away. This is Harnack's date for the nucleus of Vis.
They occasionally exhibit striation and originate from large branched cells, the nucleus and unmodified part of which form conspicuous elements. Philaret's zeal for the purity of orthodoxy sometimes led him into excesses: but he encouraged the publication of theological works, formed the nucleus of the subsequently famous Patriarchal Library, and commanded that every archbishop should establish a seminary for the clergy, himself setting the example.
The former, which was the original nucleus of all the commercial prosperity of the city, begins on the second Wednesday before Easter; and the latter on the second Wednesday before the 8th of September. The works erected by the Turks for the capture of the fortress of Arad formed the nucleus of the new town. But it was also frequently used to denote in whole or part that portion of the old Mithradatic kingdom which lay between the Halys roughly and the borders of Colchis, Lesser Armenia, Cappadocia and Galatia - the region properly designated by the title "Cappadocia towards the Pontus," which was always the nucleus of the Pontic kingdom.
Since it does not form an addition product with bromine, reduction must have taken place in one of the nuclei only, and on account of the aromatic character of the compound it must be in that nucleus which does not contain the amino group. This tetrahydro compound yields adipic acid, CH 2 4 CO 2 H 2, when oxidized by potassium permanganate.
The nucleus of the town, the ancient village, lies south of the highroad to Uxbridge, west of the open Ealing Common. Rutherford had announced the nuclear theory of atomic structure which required each atom to consist of a minute positively charged nucleus about which negative electrons were distributed.
This number is probably to be identified with the electric charge upon the nucleus of the atom. The voyage of the " Challenger " supplied for the first time the nucleus of a collection of deep-sea deposits sufficient to serve as the basis for comprehensive classification and mapping. The history of Prester John no doubt originally gathered round some nucleus of fact, though what that was is extremely difficult to determine. The district originally formed part of the parish of Kilmalcolm, the nucleus of the town being the village of Newark attached to the barony of that name.
Its dualistic system and its anti-social principles were known only to a few, but its antiecclesiastical organization formed a permanent nucleus round which gathered a great deal of political and ecclesiastical discontent.
In the nucleus of the present district of British Sikkim or Darjeeling was created by a cession of a portion of the hills by the raja of Sikkim to the British as a sanatorium. The 10th division, forming the nucleus of the 4th Army, had begun to land at Takushan on the 19th of May. Five centuries later Lauenburg was incorporated with Hanover, and Wittenberg is the nucleus of modern Saxony, the name being thus transferred from the west to the east of Germany. The latter traced the tubes as far as the nucleus of the ovule.
No portion of the regular army of the Netherlands is allowed to be sent on colonial service, but individual soldiers are at liberty to enlist, by permission of their commanding officers, in the army of Netherlands India, and they form its nucleus. General Daendels, who was governor from to , caused the ramparts of the town to be demolished, and began to form the nucleus of a new city at Weltevreden.
The other course is to consider matter as formed of ultimate atoms, each the nucleus or core of an intrinsic modification impressed on the surrounding region of the aether; this might conceivably be of the nature of vortical motion of a liquid round a ring-core, thus giving a vortex atom, or of an intrinsic strain of some sort radiating from a core, which would give an electric atom.
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