The cell membrane is a thin flexible layer around the cells of all living things. It is sometimes called the plasma membrane or cytoplasmic membrane.

Its basic job is to separate the inside of cells from the outside.
In all cells, the cell membrane separates the cytoplasm inside the cell from its surroundings. Animal cells are contained in just a membrane. Bacteria, fungi and plants have strong cell walls as well, which support the cell and block the passage of large molecules.

Structure

The membrane is made up of a thin layer called the 'phospholipid bilayer'. This has two layers of phospholipid molecules with phosphate heads on the surfaces and lipid (oil) tails on the inside. The outside heads mix with water, but the tails reject water.

Other proteins and lipids can be added to the cell membrane. By these changes, the cell can adjust what it brings in or puts out. Some proteins are always stuck into it, these are called integral membrane proteins. It also has some which are only sometimes stuck onto it. These are called peripheral membrane proteins. The outer layer protecting the inner cell.

Function

The membrane is selectively permeable.  It is active and regulates (adjusts) what comes in and what goes out of the cell.  The movement of substances across the membrane can be either passive, occurring without the input of cellular energy, or active, requiring energy.

Proteins in the membrane

Proteins within the membrane are key to its working. These proteins mainly transport chemicals and information across the membrane.

The membrane contains many proteins. The surface proteins can act as gates. They let some chemicals into the cell and let other chemicals leave the cell. It is estimated that up to a third of the human proteome may be membrane proteins. Some of these proteins are linked to the exterior of the cell membrane. An example of this is the CD59 protein, which identifies cells as "self" and thus inhibits their destruction by the immune system.

References

Cells
Organelles

Cell membrane


This article is about physical object; for meaning from audio field, see loudness.

The volume of an object is a measure of the amount of space occupied by that object, and is not to be confused with mass. The volume of a mountain is much larger than the volume of a rock, for instance.

By convention, the word volume implies a three-dimensional context where:
 The length is the longest distance between the object's extremities.
 The width (or breadth) refers to the size of the object in a direction perpendicular to its length.
 The height (or depth) stands for the size of that object in the direction perpendicular to both the length and the width.

For objects at or near the Earth's surface, height or depth often refers to the dimension of the object along the local vertical. All physical objects occupy a volume, even if some are so thin that they appear to be two-dimensional, like a sheet of paper.

Units of volume
The unit of volume in the International System of Units is the cubic meter, which is represented by the symbol m3.

In some fields or applications, one often uses different units to simplify the discussions or writings. For instance:

 Everyday quantities of liquids are often measured in units of a litre, written as L, which is the volume occupied by a cubic decimetre.
 Large quantities of liquids, such as oil, and sometimes other materials, may be measured and traded in units of barrels. There are many different reference volumes called barrels, depending on the nature of the content.

Traditional units are still in encountered in some countries: Imperial units such as the gallon or the fluid ounce were in widespread use within the British Empire. Some of them are still popular in the United States, which also uses units like the bushel, the quart, the cup and the teaspoon (in cooking recipes, for example). See U.S. customary units for more examples.

Non-conservation of volume
The volume of an object is not a fundamental property of that object: it can change with environmental conditions such as pressure and temperature, especially if the object is highly compressible.

The volume of a mixture of fluids (liquids, gases) may or may not be equal to the sum of their volumes before they were mixed.

Measuring a volume
In mathematics, the volume of simple geometric objects, written , can often be calculated on the basis of their shape and dimensions:

 The volume of a perfect cube of side c is c3.
 The volume of a rectangular box is the product of its three linear dimensions: length, width and length.
 The volume of a parallelepiped of sides a, b and c is a × b × c.
 The volume of a sphere of radius r is (4/3) π r3.
The volume of a gas is typically that of its container, but it could be ill-defined, as in the case of the atmosphere, which has no clear upper limit. The volume of a liquid is often measured by pouring it into a graduated container. The volume of a small solid can be estimated by immersing it into a graduated container partially filled with a known amount of liquid, provided the solid is not soluble in the liquid.

Related pages
 Geometry
 Surface area to volume ratio

References

Physical quantity
Geometry

Volume


Electrical impedance is the amount of opposition that a circuit presents to current or voltage change.

The two main ways to write an impedance are:
(see the 2nd figure, "complex impedance plane")

 with the resistance "R" (real part) and the reactance  "X" (imaginary part), for example
 with a magnitude and a phase (the size  and the angle ), for example  (1.4 ohm at 45 degrees)

The Impedance and the resistance are quite similar:

In the case of resistance, a resistor resists any current going through it.  The higher the resistance, the higher the voltage that is needed to achieve a given current. The formula is:

, where V is the voltage, R is the resistance, and I is the current.

In the case of impedance, an inductor resists changes to the current and the capacitor resists changes to the voltage.

The key difference between resistance and impedance is the word "change", the rate of change affects the impedance. Usually the "change" is expressed as a frequency, the number of times per second the current or voltage change direction. The formulas are:

For the inductor:

For the capacitor:

Where Z is the symbol for impedance, j is the imaginary number ,  is the constant pi, f is the frequency, L is the inductance and C is the capacitance. The units for the resistance and the impedance are the same, the ohm with the symbol  (capital omega).

As indicated by the formulas above, the impedance varies depending on the frequency, for example, at zero Hertz, or DC, the impedance of the inductor is zero, the same as a short-circuit, and the impedance of the capacitor is infinite, the same as an open-circuit. Most signals are the sum of many sine waves at various frequencies (see the fourier transform for more details), and each of them experience a different impedance.

Similarly to the resistance, the higher the impedance, the higher the voltage that is needed to achieve a given current. The formula is:

, where V is the voltage, Z is the impedance, and I is the current.

At the physical level, simplifying many things:
 the resistance is caused by the collisions of the electrons with the atoms inside the resistors.
 the impedance in a capacitor is caused by the creation of an electric field.
 the impedance in an inductor is caused by the creation of a magnetic field.

One important difference between the resistance and the impedance is that a resistor dissipates energy, it gets hot, but an inductor and a capacitor store the energy and can return that energy to the source when it goes down.

If the impedance of the source, cable and load are not all equal, then a fraction of the signal is reflected back to the source, wasting power and creating interference. The ratio of the reflection can be calculated with:

 where  (capital gamma) is the Reflection coefficient,  is the impedance of the source,  is the impedance of the load.

Any medium that can have a wave has a wave impedance, even empty space (light is an electro-magnetic wave and it can travel in space) has an impedance of about 377.

Phase

Across a resistor, both the voltage and the current goes up and down at the same time, they are said to be in phase, but with an impedance it's different, the voltage is shifted by 1/4 wavelength behind the current in a capacitor, and forward in an inductor.

A 1/4 wavelength is usually represented with the imaginary number "j", which is also equivalent to a 90 degree shift.

The use of the imaginary number "j" makes the mathematics much simpler, it allows to calculate the total impedance the same way as it's done with resistors, for example a resistor plus an impedance in series is R+Z, and in parallel it's (R*Z)/(R+Z).

impedance

Electrical impedance


The perihelion is the point in the orbit of a planet, asteroid or comet that is nearest to the sun. It is the opposite of aphelion, which is the point farthest from the sun.

The word perihelion stems from the Greek words "peri," meaning near, and "Helios," meaning the Greek god of the sun. So it is referred to as perihelion.

All planets, comets and asteroids in our solar system have approximately elliptical (a kind of non-circular) orbits. Thus, they all have a closest and a farthest point from the sun: a perihelion and an aphelion. Orbital eccentricity measures the flatness of the orbit. Any single revolution of a body around the sun is only approximately elliptical, because the precession of the perihelion prevents the orbit from being a simple closed curve such as an ellipse. This causes Milankovich cycles.

Earth comes closest to the sun every year around January 3. It is farthest from the sun every year around July 4. The difference in distance between Earth's nearest point to the sun in January and farthest point from the sun in July is 3.1 million miles (5 million kilometers). Earth is about 91.4 million miles (147.1 million kilometers) from the sun in early January, in contrast to about 94.5 million miles (152 million kilometers) in early July.

When Earth is closest to the sun, it is winter in the northern hemisphere and summer in the southern hemisphere. Thus it is possible to see that Earth's distance from the sun does not noticeably  cause the seasons to change; the relatively minor effects of differences in distance is somewhat masked by the mainly oceanic southern hemisphere vs the half- continental northern hemisphere. Therefore, the Earth's seasons come and go mainly because Earth does not rotate with its axis exactly upright with respect to the plane of our world's orbit around the sun. Earth's axial tilt is 23.5 degrees.  This puts the Sun farther south in December and January, so the north has winter and the south has summer. Thus winter falls on that part of the globe where sunlight strikes least directly. Summer falls on that part of the globe where sunlight strikes most directly.

Orbits

Perihelion


Francis Hutcheson LLD (; 8 August 1694 – 8 August 1746) was an Irish philosopher born in Ulster to a family of Scottish Presbyterians who became known as one of the founding fathers of the Scottish Enlightenment. He was Professor of Moral Philosophy at Glasgow University and is remembered as author of A System of Moral Philosophy.

Hutcheson was an important influence on the works of several significant Enlightenment thinkers, including David Hume and Adam Smith.

Early life
He is thought to have been born at Drumalig in the parish of Saintfield, County Down, in modern-day Northern Ireland. He was the "son of a Presbyterian minister of Ulster-Scottish stock, who was born in Ireland" but whose roots were in Ayrshire in Scotland. Hutcheson was educated at Killyleagh, and went on to Scotland to study at the University of Glasgow, where he spent 1710 to 1718 in the study of philosophy, classics and general literature, and afterwards in the study of theology, receiving his degree in 1712. While a student, he worked as tutor to the Earl of Kilmarnock.

Return to Ireland
Facing suspicions about his "Irish" roots and his association with New Licht theologian John Simson (then under investigation by Scottish ecclesiastical courts), a ministry for him in Scotland was unlikely to be a success, so he returned to Ireland and received a licence to preach. When, however, he was about to enter upon the pastorate of a small dissenting congregation he changed his plans in order to pursue a career in academia. He was induced to start a private academy in Dublin, where, assisted by Thomas Drennan, he taught for 10 years.

In Dublin his literary attainments gained him the friendship of many prominent inhabitants. Among these was The Rt. Hon. and Most Rev. Dr William King, the Church of Ireland Lord Archbishop of Dublin, who refused to prosecute Hutcheson in the Archbishop's Court for keeping a school without the episcopal licence. Hutcheson's relations with the clergy of the established church, especially with Archbishop King and with The Rt. Hon. and Most Rev. Dr Hugh Boulter, Lord Archbishop of Armagh, seem to have been cordial, and his biographer, speaking of "the inclination of his friends to serve him, the schemes proposed to him for obtaining promotion", etc., probably refers to some offers of preferment, on condition of his accepting episcopal ordination.

In 1725 Hutcheson married his cousin Mary, daughter of Francis Wilson of Longford. Her dowry included extensive property holdings including the townlands of Drumnacross, Garrinch, and Knockeagh, in County Longford. They had seven children of whom only one survived, also called Francis.

While living in Dublin, Hutcheson published anonymously the four essays for which he is best known: in 1725 Inquiry concerning Beauty, Order, Harmony and Design, and Inquiry concerning Moral Good and Evil, which together comprise his Inquiry into the Original of our Ideas of Beauty and Virtue; and in 1728, the Essay on the Nature and Conduct of the Passions and Affections and Illustrations upon the Moral Sense. The alterations and additions made in the second edition of these essays were published in a separate form in 1726. To the period of his Dublin residence are also to be referred the Thoughts on Laughter (1725) (a criticism of Thomas Hobbes) and the Observations on the Fable of the Bees, being in all six letters contributed to Hibernicus' Letters, a periodical that appeared in Dublin (1725–1727, 2nd ed. 1734). At the end of the same period occurred the controversy in the London Journal with Gilbert Burnet (probably the second son of The Rt. Rev. Dr Gilbert Burnet, Lord Bishop of Salisbury) on the "True Foundation of Virtue or Moral Goodness". All these letters were collected in one volume (Glasgow, 1772).

Chair of Moral Philosophy at Glasgow
In 1729, Hutcheson succeeded his old master, Gershom Carmichael, in the Chair of Moral Philosophy at the University of Glasgow, being the first professor there to lecture in English instead of Latin. It is curious that up to this time all his essays and letters had been published anonymously, but their authorship appears to have been well known. In 1730, he entered on the duties of his office, delivering an inaugural lecture (afterwards published), De naturali hominum socialitate (About the natural fellowship of mankind). He appreciated having leisure for his favourite studies; "non-levi igitur laetitia commovebar cum almam matrem Academiam me, suum olim alumnum, in libertatem asseruisse audiveram." (I was, therefore, moved by no mean frivolous pleasure when I had heard that my alma mater had delivered me, its one time alumnus, into freedom.) Yet the works on which Hutcheson's reputation rests had already been published. During his time as a lecturer in Glasgow College he taught and influenced Adam Smith, the economist and philosopher. "[T]he order of topics discussed in the economic portion of Hutcheson's System [of Moral Philosophy, 1755] is repeated by Smith in his Glasgow Lectures and again in the Wealth of Nations."

However, it was likely something other than Hutcheson's written work that had such a great influence on Smith. Hutcheson was well regarded as one of the most prominent lecturers at the University of Glasgow in his day and earned the approbation of students, colleagues, and even ordinary residents of Glasgow with the fervour and earnestness of his orations. His roots as a minister indeed shone through in his lectures, which endeavoured not merely to teach philosophy but also to make his students embody that philosophy in their lives (appropriately acquiring the epithet, preacher of philosophy). Unlike Smith, Hutcheson was not a system builder; rather, it was his magnetic personality and method of lecturing that so influenced his students and caused the greatest of those to reverentially refer to him as "the never to be forgotten Hutcheson", a title that Smith in all his correspondence used to describe only two people, his good friend David Hume and influential mentor, Hutcheson.

Other works
In addition to the works named, the following were published during Hutcheson's lifetime: a pamphlet entitled Considerations on Patronage (1735); Philosophiae moralis institutio compendiaria, ethices et jurisprudentiae naturalis elementa continens, lib. iii. (Glasgow, 1742); Metaphysicae synopsis ontologiam et pneumatologiam campleciens (Glasgow, 1742). The last work was published anonymously. After his death, his son, Francis Hutcheson published much the longest of his works, A System of Moral Philosophy, in Three Books (2 vols. London, 1755). To this is prefixed a life of the author, by Dr William Leechman, professor of divinity in the University of Glasgow. The only remaining work assigned to Hutcheson is a small treatise on Logic (Glasgow, 1764). This compendium, together with the Compendium of Metaphysics, was republished at Strasbourg in 1722.

Thus Hutcheson dealt with metaphysics, logic and ethics. His importance is, however, due almost entirely to his ethical writings, and among these primarily to the four essays and the letters published during his time in Dublin. His standpoint has a negative and a positive aspect; he is in strong opposition to Thomas Hobbes and Mandeville, and in fundamental agreement with Shaftesbury, whose name he very properly coupled with his own on the title page of the first two essays. Obvious and fundamental points of agreement between the two authors include the analogy drawn between beauty and virtue, the functions assigned to the moral sense, the position that the benevolent feelings form an original and irreducible part of our nature, and the unhesitating adoption of the principle that the test of virtuous action is its tendency to promote the general welfare.

Ethics
According to Hutcheson, man has a variety of senses, internal as well as external, reflex as well as direct, the general definition of a sense being "any determination of our minds to receive ideas independently on our will, and to have perceptions of pleasure and pain" (Essay on the Nature and Conduct of the Passions, sect. 1). He does not attempt to give an exhaustive enumeration of these "senses," but, in various parts of his works, he specifies, besides the five external senses commonly recognized (which he hints might be added to):
 consciousness, by which each man has a perception of himself and of all that is going on in his own mind (Metaph. Syn. pars i. cap. 2)
 the sense of beauty (sometimes called specifically "an internal sense")
 a public sense, or sensus communis, "a determination to be pleased with the happiness of others and to be uneasy at their misery"
 the moral sense, or "moral sense of beauty in actions and affections, by which we perceive virtue or vice, in ourselves or others"
 a sense of honour, or praise and blame, "which makes the approbation or gratitude of others the necessary occasion of pleasure, and their dislike, condemnation or resentment of injuries done by us the occasion of that uneasy sensation called shame"
 a sense of the ridiculous. It is plain, as the author confesses, that there may be "other perceptions, distinct from all these classes," and, in fact, there seems to be no limit to the number of "senses" in which a psychological division of this kind might result.

Of these "senses," the "moral sense" plays the most important part in Hutcheson's ethical system. It pronounces immediately on the character of actions and affections, approving those that are virtuous, and disapproving those that are vicious. "His principal design," he says in the preface to the two first treatises, "is to show that human nature was not left quite indifferent in the affair of virtue, to form to itself observations concerning the advantage or disadvantage of actions, and accordingly to regulate its conduct. The weakness of our reason, and the avocations arising from the infirmity and necessities of our nature, are so great that very few men could ever have formed those long deductions of reasons that show some actions to be in the whole advantageous to the agent, and their contraries pernicious. The Author of nature has much better furnished us for a virtuous conduct than our moralists seem to imagine, by almost as quick and powerful instructions as we have for the preservation of our bodies. He has made virtue a lovely form, to excite our pursuit of it, and has given us strong affections to be the springs of each virtuous action."

Passing over the appeal to final causes involved in this passage, as well as the assumption that the "moral sense" has had no growth or history, but was "implanted" in man exactly as found among the more civilized races (an assumption common to both Hutcheson and Butler), his use of the term "sense" tends to obscure the real nature of the process of moral judgement. For, as established by Hume, this act consists of two parts: an act of deliberation leading to an intellectual judgement; and a reflex feeling of satisfaction at actions we consider good, and of dissatisfaction at those we consider bad. By the intellectual part of this process, we refer the action or habit to a certain class; but no sooner is the intellectual process complete than there is excited in us a feeling similar to what myriads of actions and habits of (apparently) the same class excited in us on former occasions.

Even if the latter part of this process is instantaneous, uniform and exempt from error, the former is not. All mankind may approve of that which is virtuous or makes for the general good, but they entertain the most widely divergent opinions and frequently arrive at directly opposite conclusions as to particular actions and habits. Hutcheson recognizes this obvious distinction in his analysis of the mental process preceding moral action, and does not ignore it, even when writing on the moral approbation or disapprobation that follows action. Nonetheless, Hutcheson, both by his phraseology and the language he uses to describe the process of moral approbation, has done much to favour that loose, popular view of morality which, ignoring the necessity of deliberation and reflection, encourages hasty resolves and unpremeditated judgements.

The term "moral sense" (which, it may be noticed, had already been employed by Shaftesbury, not only, as William Whewell suggests, in the margin, but also in the text of his Inquiry), if invariably coupled with the term "moral judgement," would be open to little objection; but, taken alone, as designating the complex process of moral approbation, it is liable to lead not only to serious misapprehension but to grave practical errors. For, if each person's decisions are solely the result of an immediate intuition of the moral sense, why be at any pains to test, correct or review them? Or why educate a faculty whose decisions are infallible? And how do we account for differences in the moral decisions of different societies, and the observable changes in a person's own views? The expression has, in fact, the fault of most metaphorical terms: it leads to an exaggeration of the truth it is intended to suggest.

But though Hutcheson usually describes the moral faculty as acting instinctively and immediately, he does not, like Butler, conflate the moral faculty with the moral standard. The test or criterion of right action is with Hutcheson, as with Shaftesbury, its tendency to promote the general welfare of mankind. He thus anticipates the utilitarianism of Bentham—and not only in principle, but even in the use of the phrase "the greatest happiness for the greatest number" (Inquiry concerning Moral Good and Evil, sect. 3). Hutcheson does not seem to have seen an inconsistency between this external criterion with his fundamental ethical principle. Intuition has no possible connection with an empirical calculation of results, and Hutcheson in adopting such a criterion practically denies his fundamental assumption. Connected with Hutcheson's virtual adoption of the utilitarian standard is a kind of moral algebra, proposed for the purpose of "computing the morality of actions." This calculus occurs in the Inquiry concerning Moral Good and Evil, sect. 3.

Hutcheson's other distinctive ethical doctrine is what has been called the "benevolent theory" of morals. Hobbes had maintained that all other actions, however disguised under apparent sympathy, have their roots in self-love. Hutcheson not only maintains that benevolence is the sole and direct source of many of our actions, but, by a not unnatural recoil from the repellent doctrine of Hobbes, that it is the only source of those actions of which, on reflection, we approve. Consistently with this position, actions that flow from self-love only are morally indifferent. But surely, by the common consent of civilized men, prudence, temperance, cleanliness, industry, self-respect and, in general, the "personal virtues", are regarded, and rightly regarded, as fitting objects of moral approbation.

This consideration could hardly escape any author, however wedded to his own system, and Hutcheson attempts to extricate himself from the difficulty by laying down the position that a man may justly regard himself as a part of the rational system, and may thus "be, in part, an object of his own benevolence" (Ibid.), a curious abuse of terms, which really concedes the question at issue. Moreover, he acknowledges that, though self-love does not merit approbation, neither, except in its extreme forms, did it merit condemnation, indeed the satisfaction of the dictates of self-love is one of the very conditions of the preservation of society. To press home the inconsistencies involved in these various statement would be a superfluous task.

The vexed question of liberty and necessity appears to be carefully avoided in Hutcheson's professedly ethical works. But, in the Synopsis metaphysicae, he touches on it in three places, briefly stating both sides of the question, but evidently inclining to what he designates as the opinion of the Stoics, in opposition to what he designates as the opinion of the Peripatetics. This is substantially the same as the doctrine propounded by Hobbes and Locke (to the latter of whom Hutcheson refers in a note), namely that our will is determined by motives in conjunction with our general character and habit of mind, and that the only true liberty is the liberty of acting as we will, not the liberty of willing as we will. Though, however, his leaning is clear, he carefully avoids dogmatising, and deprecates the angry controversies to which the speculation on this subject had given rise.

It is easy to trace the influence of Hutcheson's ethical theories on the systems of Hume and Adam Smith. The prominence given by these writers to the analysis of moral action and moral approbation with the attempt to discriminate the respective provinces of the reason and the emotions in these processes, is undoubtedly due to the influence of Hutcheson. To a study of the writings of Shaftesbury and Hutcheson we might, probably, in large measure, attribute the unequivocal adoption of the utilitarian standard by Hume, and, if this be the case, the name of Hutcheson connects itself, through Hume, with the names of Priestley, Paley and Bentham. Butler's Sermons appeared in 1726, the year after the publication of Hutcheson's two first essays, and there are parallels between the "conscience" of the one writer and the "moral sense" of the other.

Death

Francis Hutcheson spent time in Dublin, and died while on a visit to that city in 1746. He is buried in the churchyard of Saint Mary's, which is also the final resting place of his cousin William Bruce. Today Saint Mary's is a public park located in what is now Wolfe Tone Street. Many United Irishmen would have revered the memory of Francis Hutcheson. Some of the leaders of the Dublin United Irishmen are remembered in the street and place-names of the city.
Most Dubliners can direct a visitor to Wolfe Tone Street, Oliver Bond Street, Russell Street, Lord Edward Street and Emmet Road. "Never to be forgotten Hutcheson" lies in what is now an unmarked grave in the Dublin he loved and "where his best work was done".

Mental philosophy

In the sphere of mental philosophy and logic, Hutcheson's contributions are by no means so important or original as in that of moral philosophy. They are interesting mainly as a link between Locke and the Scottish school. In the former subject the influence of Locke is apparent throughout. All the main outlines of Locke's philosophy seem, at first sight, to be accepted as a matter of course. Thus, in stating his theory of the moral sense, Hutcheson is peculiarly careful to repudiate the doctrine of innate ideas (see, for instance, Inquiry concerning Moral Good and Evil, sect. I ad fin., and sect. 4; and compare Synopsis Metaphysicae, pars i. cap. 2). At the same time he shows more discrimination than does Locke in distinguishing between the two uses of this expression, and between the legitimate and illegitimate form of the doctrine (Syn. Metaph. pars i. cap. 2).

All our ideas are, as by Locke, referred to external or internal sense, or, in other words, to sensation and reflection. It is, however, a most important modification of Locke's doctrine, and connects Hutcheson's mental philosophy with that of Reid, when he states that the ideas of extension, figure, motion and rest "are more properly ideas accompanying the sensations of sight and touch than the sensations of either of these senses"; that the idea of self accompanies every thought, and that the ideas of number, duration and existence accompany every other idea whatsoever (see Essay on the Nature and Conduct of the Passions, sect. i. art. I; Syn. Metaph. pars i. cap. 1, pars ii. cap. I; Hamilton on Reid, p. 124, note). Other important points in which Hutcheson follows the lead of Locke are his depreciation of the importance of the so-called laws of thought, his distinction between the primary and secondary qualities of bodies, the position that we cannot know the inmost essences of things ("intimae rerum naturae sive essentiae"), though they excite various ideas in us, and the assumption that external things are known only through the medium of ideas (Syn. Metaph. pars i. cap. I), though, at the same time, we are assured of the existence of an external world corresponding to these ideas.

Hutcheson attempts to account for our assurance of the reality of an external world by referring it to a natural instinct (Syn. Metaph. pars i. cap. 1). Of the correspondence or similitude between our ideas of the primary qualities of things and the things themselves God alone can be assigned as the cause. This similitude has been effected by Him through a law of nature. "Haec prima qualitatum primariarum perceptio, sive mentis actio quaedam sive passio dicatur, non-alia similitudinis aut convenientiae inter ejusmodi ideas et res ipsas causa assignari posse videtur, quam ipse Deus, qui certa naturae lege hoc efilcit, Ut notiones, quae rebus praesentibus excitantur, sint ipsis similes, aut saltem earum habitudines, si non-veras quantitates, depingant" (pars ii. cap. I). Locke does speak of God "annexing" certain ideas to certain motions of bodies; but nowhere does he propound a theory so definite as that here propounded by Hutcheson, which reminds us at least as much of the speculations of Nicolas Malebranche as of those of Locke.

Amongst the more important points in which Hutcheson diverges from Locke is his account of the idea of personal identity, which he appears to have regarded as made known to us directly by consciousness. The distinction between body and mind, corpus or materia and res cogitans, is more emphatically accentuated by Hutcheson than by Locke. Generally, he speaks as if we had a direct consciousness of mind as distinct from body, though, in the posthumous work on Moral Philosophy, he expressly states that we know mind as we know body" by qualities immediately perceived though the substance of both be unknown (bk. i. ch. 1). The distinction between perception proper and sensation proper, which occurs by implication though it is not explicitly worked out (see Hamilton's Lectures on Metaphysics, – Lect. 24).

Hamilton's edition of Dugald Stewart's Works, v. 420 (the imperfection of the ordinary division of the external senses into two classes, the limitation of consciousness to a special mental faculty) (severely criticized in Sir W Hamilton's Lectures on Metaphysics Lect. xii.) and the disposition to refer on disputed questions of philosophy not so much to formal arguments as to the testimony of consciousness and our natural instincts are also amongst the points in which Hutcheson supplemented or departed from the philosophy of Locke. The last point can hardly fail to suggest the "common-sense philosophy" of Reid.

Thus, in estimating Hutcheson's position, we find that in particular questions he stands nearer to Locke, but in the general spirit of his philosophy he seems to approach more closely to his Scottish successors.

The short Compendium of Logic, which is more original than such works usually are, is remarkable chiefly for the large proportion of psychological matter that it contains. In these parts of the book Hutcheson mainly follows Locke. The technicalities of the subject are passed lightly over, and the book is readable. It may be specially noticed that he distinguishes between the mental result and its verbal expression judgment-proposition, that he constantly employs the word "idea," and that he defines logical truth as "convenientia signorum cum rebus significatis" (or "propositionis convenientia cum rebus ipsis," Syn. Metaph. pars i. cap. 3), thus implicitly repudiating a merely formal view of logic.

Aesthetics

Hutcheson may further be regarded as one of the earliest modern writers on aesthetics. His speculations on this subject are contained in the Inquiry concerning Beauty, Order, Harmony and Design, the first of the two treatises published in 1725. He maintains that we are endowed with a special sense by which we perceive beauty, harmony and proportion. This is a reflex sense, because it presupposes the action of the external senses of sight and hearing. It may be called an internal sense, both to distinguish its perceptions from the mere perceptions of sight and hearing, and because "in some other affairs, where our external senses are not much concerned, we discern a sort of beauty, very like in many respects to that observed in sensible objects, and accompanied with like pleasure" (Inquiry, etc., sect. 1, XI). The latter reason leads him to call attention to the beauty perceived in universal truths, in the operations of general causes and in moral principles and actions. Thus, the analogy between beauty and virtue, which was so favourite a topic with Shaftesbury, is prominent in the writings of Hutcheson also. Scattered up and down the treatise there are many important and interesting observations that our limits prevent us from noticing. But to the student of mental philosophy it may be specially interesting to remark that Hutcheson both applies the principle of association to explain our ideas of beauty and also sets limits to its application, insisting on there being "a natural power of perception or sense of beauty in objects, antecedent to all custom, education or example" (see Inquiry, etc., sects. 6, 7; Hamilton's Lectures on Metaphysics, Lect. 44 .).

Hutcheson's writings gave rise to much controversy. To say nothing of minor opponents, such as "Philaretus" (Gilbert Burnet, already alluded to), Dr John Balguy (1686–1748), prebendary of Salisbury, the author of two tracts on "The Foundation of Moral Goodness", and Dr John Taylor (1694–1761) of Norwich, a minister of considerable reputation in his time (author of An Examination of the Scheme of Amorality advanced by Dr Hutcheson), the essays appear to have suggested, by antagonism, at least two works that hold a permanent place in the literature of English ethics—Butler's Dissertation on the Nature of Virtue, and Richard Price's Treatise of Moral Good and Evil (1757). In this latter work the author maintains, in opposition to Hutcheson, that actions are – in themselves right or wrong, that right and wrong are simple ideas incapable of analysis, and that these ideas are perceived immediately by the understanding. We thus see that, not only directly but also through the replies that it called forth, the system of Hutcheson, or at least the system of Hutcheson combined with that of Shaftesbury, contributed, in large measure, to the formation and development of some of the most important of the later schools of ethics.

Later scholarly mention
References to Hutcheson occur in histories, both of general philosophy and of moral philosophy, as, for instance, in pt. vii. of Adam Smith's Theory of Moral Sentiments; Mackintosh's Progress of Ethical Philosophy; Cousin, Cours d'histoire de la philosophie morale du XVIII' siècle; Whewell's Lectures on the History of Moral Philosophy in England; A Bain's Mental and Moral Science; Noah Porter's Appendix to the English translation of Ueberweg's History of Philosophy; Sir Leslie Stephen's History of English Thought in the Eighteenth Gentury, etc. See also Martineau, Types of Ethical Theory (London, 1902); WR Scott, Francis Hutcheson (Cambridge, 1900); Albee, History of English Utilitarianism (London, 1902); T Fowler, Shaftesbury and Hutcheson (London, 1882); J McCosh, Scottish Philosophy (New York, 1874). Of Dr Leechman's Biography of Hutcheson we have already spoken. J. Veitch gives an interesting account of his professorial work in Glasgow, Mind, ii. 209–12.

Influence in Colonial America

Norman Fiering, a specialist in the intellectual history of colonial New England, has described Francis Hutcheson as "probably the most influential and respected moral philosopher in America in the eighteenth century". Hutcheson's early Inquiry into the Original of Our Ideas of Beauty and Virtue, introducing his perennial association of "unalienable rights" with the collective right to resist oppressive government, was used at Harvard College as a textbook as early as the 1730s. In 1761, Hutcheson was publicly endorsed in the annual semi-official Massachusetts Election Sermon as "an approved writer on ethics." Hutcheson's Short Introduction to Moral Philosophy was used as a textbook at the College of Philadelphia in the 1760s. Francis Alison, the professor of moral philosophy at the College of Philadelphia, was a former student of Hutcheson who closely followed Hutcheson's thought. Alison's students included "a surprisingly large number of active, well-known patriots", including three signers of the Declaration of Independence, who "learned their patriotic principles from Hutcheson and Alison". Another signer of the Declaration of Independence, John Witherspoon of the College of New Jersey (now Princeton University), relied heavily on Hutcheson's views in his own lectures on moral philosophy.

John Adams read Hutcheson's Short Introduction to Moral Philosophy shortly after graduating from Harvard. Garry Wills argued in 1978 that the phrasing of the Declaration of Independence was due largely to Hutcheson's influence, but Wills's work suffered a scathing rebuttal from Ronald Hamowy. Wills' view has been partially supported by Samuel Fleischacker, who agreed that it is "perfectly reasonable to see Hutcheson's influence behind the appeals to sentiment that Jefferson put into his draft of the Declaration..."

Selected other works
 Reflections Upon Laughter: And REMARKS UPON The FABLE of the BEES. – Garland Publishing, 1750

See also
 List of abolitionist forerunners

References

Sources

External links

 Contains versions of Origin of ideas of Beauty etc. and of Virtue etc., slightly modified for easier reading
 Francis Hutcheson Internet Encyclopedia of Philosophy article

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Francis Hutcheson (philosopher)


The brainstem is the rear part of the brain. It has two sections: the hindbrain, which includes the pons and medula, and the midbrain.

Though the brainstem is small, it is extremely important. The motor (movement) and sensory connections from the main part of the brain to the rest of the body pass through the brain stem. Also, from the brainstem come the main motor and sensory nerves to the face and neck. These nerves are called the cranial nerves. The brainstem controls many bodily functions of which we are not normally aware, such as breathing, heart beat, and sweating. The brainstem controls functions which are unconscious, but necessary for life.

The hindbrain consists of the pons, and the medulla oblongata; which is an extension of the spinal cord.  It connects the other parts of the brain (the cerebrum and cerebellum) to the spinal cord. Its neurons are the control centre of bodily functions, such as breathing and blood pressure.

Functions of the brainstem
Conduction All information going between the body and the cerebellum and the cerebrum must go through the brainstem.
Nerves Cranial nerves 3–12 emerge from the brainstem. There are motor neurons in the brainstem that allow movement in the face, including speech and swallowing.
Integration It is involved in cardiovascular system control, respiratory control, pain sensitivity control, alertness, awareness, and consciousness. Thus, brainstem damage is a serious and often life-threatening problem.

Anatomy of the brain

Brain stem


Heimdall (or Heimdallr) is one of the gods in Northern mythology. He is the guardian of the Bifröst Bridge. He was the son of nine different mothers and was called the White God.

Heimdall is the guardian of the gods. He will blow a horn, called the Gjallarhorn, if Asgard is in danger. His senses are so good that he can hear the grass grow and he can see to the end of the world. Heimdall could hear a leaf fall. He does not need any sleep at all.

Heimdall was said to be the last of the gods to die at Ragnarok when he and Loki would kill one another.

Norse gods and goddesses

Heimdall


River dolphins are five species of dolphin which live in fresh water rivers and estuaries. Three species live in fresh water rivers. The La Plata Dolphin lives in salt water estuaries and the ocean.

South Asian river dolphins (two sub-species)
Ganges river dolphin, Platanista gangetica gangetica – Lives in Nepal, Republic of India and Bangladesh
 Indus river dolphin, Platanista indicus minor – Lives in Pakistan; National mammal of Pakistan.
South American river dolphins (three species)
 Amazon river dolphin (or Boto), Inia geoffrensis – Largest of river dolphins, lives in Peru and Brazil.
Araguaia river dolphin, Inia araguaiaensis  – Recently discovered in the river basin in Brazil after which it is named. Identified as a separate species by genetic sequence analysis.
 La Plata dolphin (or Franciscana), Pontoporia blainvillei – Lives in Argentina.
 Chinese river dolphin (or Baiji), Lipotes vexillifer – Lives in the Yangtze River in China (one of the most endangered of all dolphins and whales). Recent counts have come up with 17 remaining individuals. Scientists now want to raise some dolphins in a lake.

Differences between marine and river dolphins
Both river dolphins and marine dolphins belong to a group of mammals called cetaceans. The snout of a river dolphin measures about 58 centimeters (2 ft) long, approximately four times as long as that of most marine dolphins. They use their long snout to search for fish on the muddy bottom of the river. River dolphins have smaller eyes than marine dolphins, and their vision is poorly developed because they live in dark, muddy water. River dolphins are less active than marine dolphins because they do not need to search so widely to find fish. Marine dolphins work in pods (packs) because when they find a shoal of fish then they work together to make the most of their find. River dolphins work mostly as individuals or small groups.

Taxonomy
The following is the taxonomy of river dolphins, or how dolphins are classified:

River dolphin classification
 Superfamily Platanistoidea
 Family Platanistidae
 South Asian river dolphin Platanista gangetica (two subspecies)
 Ganges river dolphin P. g. gangetica
 Indus dolphin P. g. minor
 Family Iniidae
 Amazon river dolphin (or Boto) Inia geoffrensis
 Family Lipotidae
 Chinese river dolphin (or Baiji) Lipotes vexillifer
 Family Pontoporiidae
 La Plata dolphin (or Franciscana) Pontoporia blainvillei

References

Other sources
River-Dolphins-and-their-habitat

River dolphin


Edward Benjamin Britten, Baron Britten of Aldeburgh, OM CH (born Lowestoft, 22 November 1913; died Aldeburgh, 4 December 1976) was one of the greatest English composers of his time.  He came from East Anglia (a region in the East of England) and he often thought about the East Anglian landscape and the sea when writing his music.  He wrote a lot of music for his long-term partner, the tenor Peter Pears.  His operas include Peter Grimes, Billy Budd, A Midsummer Night's Dream, and Death in Venice. His War Requiem was performed in Coventry Cathedral in 1962 after it had been rebuilt because the old cathedral had been destroyed in the war.  He wrote music for children which sounds like proper, adult music.  Britten started the Aldeburgh Festival.  He was an excellent pianist and conductor.

Life

Early years
Benjamin Britten started composing music at the age of five although he had no one to help him. When he was ten years old he took part in an amateur music festival in Norwich.  A composer called Frank Bridge heard him and was so impressed that he offered to teach him composition.  He helped Britten to compose using proper musical techniques.  Britten started to get to know music by a lot of important modern composers including Schoenberg and Bartók.  In 1930 he went to the Royal College of Music.  He had excellent piano teachers but he did not learn much from his composition teacher John Ireland and most of the music he wrote was never performed.  Britten was more interested in music from abroad than in English music.  In 1934 he heard the opera Wozzeck by Alban Berg.  He wanted to go to Austria to study with Berg but he was not allowed to.  Meanwhile, some of his first proper compositions started to be performed.  He wrote some music for movies that were being made by the General Post Office, including one about a train delivering mail.  The music describes the rhythm of the train rushing along.

USA
While working on the movie music he met the writer W. H. Auden.  He started to be interested in political ideas.   These can be heard in some works he wrote at this time such as Our Hunting Fathers (1936) and Ballad of Heroes (1939).  When Auden emigrated to the United States Britten followed him.  With him was the tenor Peter Pears who was to become a lifelong friend and partner, and who was to be the inspiration for many songs and operas.

Britten wrote several compositions in the USA including Sinfonia da Requiem (1940) and his First String Quartet (1941).  The following year he was reading about the poet George Crabbe who came from Suffolk, the same part of England where Britten had grown up.  Britten suddenly became homesick.  He realized that he could not work and be himself in a foreign country.  So he returned with Pears to England.

Aldeburgh Festival
As soon as he was on the boat sailing back to England he started work on Ceremony of Carols.  Back in England, Britten and Pears gave concerts to audiences of all kinds and took part in opera productions of Sadler's Wells Opera Company, which was having a new theatre built.  On the 7 June 1945 the new theatre was opened with a performance of Britten's opera Peter Grimes.  This opera was to make Britten into the most famous English composer of his time.  It was soon being performed abroad as well as in England.

Britten was now composing lots of music: songs, chamber music and a very popular piece called Young Person's Guide to the Orchestra (also known as Variations and Fugue on a Theme of Purcell).  This piece shows off each instrument of the orchestra in turn so that young people can get to know the sound of the musical instruments.  It is based on a tune written by Henry Purcell 300 years ago.  There were more popular works: St Nicolas and the Spring Symphony.  There were not many opportunities for big operas to be performed, so he wrote some "chamber operas" which only needed small orchestras and a small number of singers.  These were performed in places such as local churches by a group which called themselves English Opera Group.  He wrote The Rape of Lucretia (1946) and Albert Herring (1947).  In 1948 the group helped to start a music festival in Aldeburgh.  Benjamin Britten spent the rest of his life mainly working on music which was to be performed at the Aldeburgh Festival.  He composed some of his greatest works for the festival, and he took part in the performances as conductor and pianist.

The 1950s
One of Britten's most popular pieces of music for amateurs including children was Noye's Fludde (1957).  He wrote three "church parables".  His large operas include Billy Budd (1951) which was soon produced in Covent Garden.  In June 1953 he wrote Gloriana, an opera about Queen Elizabeth I, written for the coronation celebrations of Elizabeth II.  When he travelled with Peter Pears to the Far East he was influenced by the music of Bali and he composed a ballet called The Prince of the Pagodas, performed in Covent Garden in 1957.  Another great work inspired by the East was the parable Curlew River (1964).  The opera A Midsummer Night's Dream was written for the Aldeburgh Festival in 1960. In 1962 he wrote the War Requiem to celebrate the new Coventry Cathedral.  This is one of the greatest musical works of the 20th century.

His last years
In 1961 he became friends with the great Russian cellist Mstislav Rostropovich. He composed a Cello Sonata and a Cello Symphony (1963) (a kind of cello concerto), as well as three suites for solo cello. He travelled with Pears to the Soviet Union.

In 1967 the Aldeburgh Festival had a new concert hall, the Maltings at Snape. His next opera was Owen Wingrave (1970), written for television but soon produced in Covent Garden. In June 1973 Britten produced another great opera Death in Venice. The main character, called Aschenbach, was perhaps the best music he ever wrote for Peter Pears. It was performed at the Aldeburgh Festival, but Britten was ill by this time and unable to be at the performance. His heart condition made it impossible to work on any more large works, but he still wrote some harp music for the harpist Ossian Ellis, a song called Phaedra for Janet Baker, and a Third String Quartet. He died in Aldeburgh on 4 December 1976.

Britten received many honours both in Britain and in other countries. He became a Companion of Honour in 1952 a member of the Order of Merit in 1965 and, in the year he died, he was the first musician ever to receive a life peer (the title Lord Britten).

His music
Britten's early works were often written for instruments.  His Variations on a Theme of Frank Bridge (1937) for string orchestra is a very popular work today.  He often borrowed and reinvented themes by other composers (this is called "parody" technique).  During his last years he again gave much attention to instrumental music, mainly chamber music.

After he met Peter Pears much of his music was vocal.  This includes more than 100 songs, a number of operas, chamber operas as well as three works for tenor solo and orchestra: Les Illuminations, the Serenade for Tenor, Horn and Strings and the Nocturne.  His songs are often grouped in cycles.  He also wrote many folksong settings.  These were very popular as encore pieces when he accompanied Peter Pears in song recitals.

Britten wrote music for choirs, including Hymn to St Cecilia (Britten was proud of having been born on St Cecilia's day: 22 November).  The War Requiem is his greatest work which combines writing for choir and orchestra.  It describes the horrors of war (Britten had refused to fight in World War II).

He wrote a lot of work for children.  There are even parts for children in some of his operas, e.g. Peter Grimes, The Turn of the Screw and Owen Wingrave.  He even wrote an opera in which all the main parts are sung by children: The Little Sweep (1949).

Many of his great operatic roles, from Peter Grimes to Aschenbach in Death in Venice, deal with the theme of the outsider, the person who does not quite fit into society, or who is misunderstood.  Britten's homosexuality (which was something that was never discussed in his lifetime) may have something to do with this.  He also knew what it was like to be an outsider when he tried to live in the United States, and his refusal to fight in the war may have distanced him from some people.

The Aldeburgh Festival at the Maltings in Snape (a village near Aldeburgh) continue to be a focus for Britten's music.  Every year the Brittens-Pears School of Music organizes lessons and performance opportunities for young musicians.  A series of "Prom" concerts is held there every year in August.

References

20th-century English composers
British conductors
Companions of Honour
Deaths from heart failure
English LGBT people
English pianists
Gay men
Grammy Award winners
LGBT composers
LGBT musicians
Musicians from Suffolk
Order of Merit
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Benjamin Britten


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Okinawa is the name for the biggest island in the Ryūkyū Islands, far south of Japan. It is also the common name for Okinawa Prefecture, which controls the Southern Ryūkyū Islands.

The capital of Okinawa is Naha. Naha is on the island with the most people, Okinawa island. Okinawa used to be called Great Lew Chew Island.

Okinawa is home to the Okinawan people, who also inhabit the minor islands surrounding Okinawa as well. There are also many Japanese in Okinawa.

Many of Okinawa's islands are scenic, and there are many beaches there.

The temperature in Okinawa is often warm or hot.  Many animals make their home around the Okinawa islands.  For example, sea turtles, jellyfish, and many kinds of birds all live around Okinawa.

An average person in Okinawa lives to be older than 100 years old. Some people think that is because Okinawan food is healthy. Fish is very popular, but people also eat sea vegetables and pork. Okinawans are known as easygoing people, almost everyone loves to sing and dance. Okinawa's music is popular all over Japan.  A musical instrument called a sanshin is often used. They celebrate their musical instrument every year on March 4th by singing folk songs together. Okinawans when compared with Japanese are peaceful people. They placed sanshin on their tokonoma while on Japanese mainland tend to display samurai.

Okinawan food is famous for its originality. Examples of local specialties are Okinawa Soba, Go-ya Champuru, Rafute, and Ji-mami-doufu.

Okinawa was the site of the last big battle of World War II, the Battle of Okinawa. A lot of Okinawan people died during the battle. Now, the United States has some military bases for soldiers on the different islands of Okinawa. There are some symbols of this battle in Okinawa. The Himeyuri Monument is the most famous symbol.

History
Okinawa is currently a part of Japan. However, it has its own history and culture distinguished from Japan. The history of Okinawa is usually divided into five eras as follows.
 Prehistoric era (Tens of thousands of years ago~12th century)
 Old Ryukyu era (12th century~1609)
 Early modern Ryukyu era (1609~1879)
 Modern Okinawa era (1879~1945)
 Post-war era (1945~)

In the prehistoric era, hunting animals and collecting plants prevailed. A shift to farming advanced during the 10th to 12th centuries. Many communities were formed, and integrated into the three small countries of Hokuzan, Chūzan, and Nanzan. In 1372, Chūzan began paying tribute to the Chinese Ming Dynasty. This small country became strong by trade with the Ming dynasty, and attacked the other countries. It became the "Ryūkyū Kingdom". This kingdom flourished through trade throughout Asia during the 15th and 16th centuries.

In 1609, Shimazu Iehisa invaded the Ryūkyū Kingdom. He was the feudal lord of Satsuma Province. This invasion meant that the Ryūkyū Kingdom was forced to pay tribute to the Japanese shogunate regime. This domination continued until the end of the 19th century.

In 1867, the Japanese shogunate ended and power was returned to the Emperor Meiji. The new government had a policy to incorporate the Ryūkyū Kingdom into the Japanese Empire. The Ryūkyū Kingdom was reorganized. At first, in 1872, the Ryūkyū Kingdom was renamed Ryūkyū Domain, meaning that it was directly controlled by Japan instead of Satsuma Province. In 1879, it was reorganized as Okinawa Prefecture. The Ryūkyū Kingdom was ended at that time. Okinawa became a Japanese colony.

At first, Japan emphasized the differences between Okinawan and Japanese culture, to justify discriminatory policies in the colony. However, to justify the colonization to the West, the policies were changed to ones which emphasized similarities and which assimilated Okinawa into Japan. Thus, Okinawan society has been greatly influenced by Japan. The Japanese taught Okinawan children that the Okinawan language was a "dialect" of Japanese, and students were punished for speaking their native language. Okinawa was caught up in the Japanese war against U.S.A. and China. Okinawa was incorporated into the war system. At the end of World War II, Okinawa itself became the battlefield, the social infrastructure was completely destroyed, and many people died.

After the war, Okinawa was put under the U.S. military. The people expected freedom, but priority was given to U.S. military policy. Therefore, the movement for a return to Japan was strengthened, and it was carried out in 1972. However, the problem continues up to the present as the Japanese government continues to give priority to U.S. military policy. Many US military bases are still left, and crimes by a few US soldiers continue to be a social problem.

Related pages
 Provinces of Japan
 Prefectures of Japan
 List of regions of Japan
 List of islands of Japan

References

Islands of Japan
Ryukyu Islands
Okinawa Prefecture

Okinawa


A synagogue is a place where Jews meet to worship and pray to God.

In Hebrew, a synagogue is called beit knesset, which means, a "house of gathering". The word "synagogue" comes from sunagoge, which is a Greek word. In a synagogue, Jews carry out the Jewish services, which consist of prayers, sometimes with special actions.

A synagogue will usually have a large room for prayers. There might be some smaller rooms for studying. There will be some offices. There will also usually be a big room for special events.

The front of a synagogue faces towards Jerusalem in Israel.  In the front is the holiest part of the synagogue, the Ark. This is a closet which has the Torah scrolls inside.  The Torah scrolls have the holy writings of Judaism on them.  The Ark usually has a curtain in front of it.

On top of the Ark is light which is always lit, called the "Eternal Lamp". It is a symbol which means that God is always there.
Every synagogue has a raised platform called the "Bimah". The person who reads the Torah scroll stands there when he reads. The Bimah is either in the middle of the hall, or in front of the Ark.

In some synagogues men and women sit in different places. Some synagogues even have a short wall so that they can not see each other. This is so that the people will think about the prayers better.

Jews may call synagogues by different names. Many Orthodox and Conservative Jews living in English-speaking countries use the name "synagogue" or the word "shul", which is Yiddish. Jews who speak Spanish or Portuguese call synagogues esnoga. Some Jews call the synagogue a temple.

Jewish worship does not have to be carried out in a synagogue.  It can be wherever a minyan of ten Jews are. It could be in someone's home or anywhere such as a cruise liner or an airplane. Some synagogues have a separate room or torah study, this is called the "beth midrash" meaning house of study. Some kinds of Jewish worship can be done alone or with fewer than ten people.
Synagogues are places were Jews can worship.

Synagogue


An invention is a new thing that someone has made. The computer was an invention when it was first made. We say when it was "invented". New things that are made or created are called inventions. Cars and plastics are inventions that everyone knows. Inventions are made by inventors. Many inventions are patented.

Ideas are also called inventions. Writers can invent characters, and then invent a story about them.

Inventing
Over time, humans have invented objects which make life easier for themselves. Because of this, a quote "necessity is the mother of invention", was written. The quote means that a lack of something should inspire someone to create something to fill that empty space. However, not all people believe that this is true. They think that too much of something can lead to an invention.
Many inventions are just a variation of something that already exists.

Other websites

 List of PCT (Patent Cooperation Treaty) Important Inventions  (on the WIPO web site)

Basic English 850 words

Invention


Pyotr Ilyich Tchaikovsky (, Pëtr Il'ič Čajkovskij; ) (born Kamsko-Votkinsk, 7 May 1840; died St Petersburg, 6 November 1893; pronounced chai-KOV-skee) was a Russian composer who lived in the Romantic period. He is one of the most popular of all Russian composers. He wrote melodies which were usually dramatic and emotional. He learned a lot from studying the music of Western Europe, but his music also sounds very Russian. His compositions include 11 operas, 3 ballets, orchestral music, chamber music and over 100 songs. His famous ballets (Swan Lake, The Nutcracker  and Sleeping Beauty) have some of the best known tunes in all of romantic music. He is widely regarded as the greatest composer of ballets.

Early years

Tchaikovsky's father was a Ukrainian who worked as a mining engineer. His mother's grandfather was a Frenchman who had moved to Russia. She was a nervous woman and Tchaikovsky may have gotten his nervous character from her. Tchaikovsky was only five when he started taking piano lessons.  He was soon better than his teacher. The family had an orchestrion (a kind of musical box) which played some tunes from classical music by Mozart, Bellini, Donizetti and Rossini.

In 1848 the family moved to St. Petersburg. Tchaikovsky was unhappy and unsettled as he was often separated from his family who moved several times. In 1854 his mother died. He tried to comfort himself by playing music. He spent nine years at the School of Jurisprudence. When he left school, he had to get a job. For four years he worked as a clerk in the Ministry of Justice. Then the composer and pianist Anton Rubinstein helped him to become a music student at the newly opened conservatory in St. Petersburg. He learned to play the flute and the organ as well as the piano and learning all about composition. In 1866 he moved to Moscow where Nikolai Rubinstein, the brother of Anton, encouraged him to write music with a Russian character. He worked very hard, and was often exhausted, but he managed to finish his First Symphony, which was performed in 1868.

Tchaikovsky met some famous musicians including the French composer Berlioz who was visiting Moscow. He also became friendly with the Russian composer Mily Balakirev who was very helpful and persuaded him to rewrite one of his works several times until it was very good. he result was a piece for orchestra called Romeo and Juliet which soon became internationally known. Balakirev had four friends who were composers. This circle of friends is often called "The Five" or "The Mighty Handful". They were interested in using Russian folktunes in their music. Tchaikovsky was never a member of the group, although he liked their ideas. Tchaikovsky was different to them: he had learned music at the Conservatoire where he had studied Western music. The harmonies that he used in his works were often not suitable for Russian folktunes. He wrote many songs which are romantic in character. One of them, None But the Lonely Heart, is especially well known in English.

By now, Tchaikovsky was writing works which were to make him very famous. He wrote two more symphonies, and his First Piano Concerto, one of the most popular of all piano concertos, was given its first performance in Boston. He was also writing operas and chamber music.

Years of fame
In 1875, Tchaikovsky began making a long tour of Europe. He liked Bizet's opera Carmen, but Wagner's operas from the Ring cycle bored him. In 1877 he finished Swan Lake, the first of his three ballets. The audience did not like it at first because the dancers were not very good.

Tchaikovsky was a closeted homosexual. In the summer of 1877 Tchaikovsky decided to marry. His wife was called Antonina Milyukova. The marriage was a disaster. A few weeks after the marriage, he ran away and never lived with her again.

Another woman was to become important in his life, but in a very different way. It was to be a very unusual relationship. Her name was Nadezhda von Meck. She was the wife of a rich man. She loved Tchaikovsky's music and promised him that she would pay him a lot of money every month so long as he promised her that he would never try to meet her.  Tchaikovsky no longer needed to work. He was able to give up his teaching job at the Conservatory. For several years he spent the winters in Europe and the summers in Russia.  Nadezhda and Tchaikovsky wrote long letters to one another, often quite passionate and dreamy they talked about love, life and how they wanted it to change, but they never saw one another. He had plenty of time to write music: he wrote several operas including Eugene Onegin and his Fourth and Fifth Symphonies, the Violin Concerto, the Serenade for Strings, Capriccio Italienne and the 1812 Overture. Tchaikovsky loved Nadezhda very much but never actually told her his true feelings.

His last years

By 1885, Tchaikovsky had tired of travelling around. He rented a country house in Klin, just outside Moscow. He lived a regular life, reading, walking in the forest, composing during the day and playing music with his friends in the evenings. He started to have more confidence as a conductor and toured Europe twice, conducting in Leipzig, Berlin, Prague, Hamburg, Paris and London. In 1889 he finished his second ballet, The Sleeping Beauty and the next year, while staying in Florence, he wrote his famous opera The Queen of Spades based on a story by Pushkin. Later that year Nadezhda von Meck wrote to him that she had lost nearly all her money and could not continue to support him.

In the spring of 1891 he was invited to conduct in New York where the Carnegie Hall was being opened. He also conducted concerts in Baltimore and Philadelphia. When he returned to Russia he wrote his last ballet The Nutcracker and his Sixth Symphony, known as the "Pathétique" which was dedicated to his nephew with whom he was passionately in love. This work is often considered his best. It was performed in St Petersburg on October 16 1893.  Five days later he suddenly became ill with cholera, a disease many people were catching in the city. Tchaikovsky died four days later. Many people think that he committed suicide by deliberately drinking contaminated water. He may have wanted to (or even been forced to) commit suicide in order to avoid a scandal because he was having a relationship with a nephew of an important aristocratic man. Exactly what happened is still a mystery.

References

1840 births
1893 deaths
LGBT composers
Romantic composers
Russian composers
Russian LGBT people
Unexplained deaths

Pyotr Ilyich Tchaikovsky


Caching is a term used in computer science.  The idea behind a  cache (pronounced "cash"   ) is very simple: Very often, obtaining a result for a calculation is very time-consuming, so storing the result is generally a good idea. Two kinds of storage media are used: One is usually quite big, but accessing it is "slow"; the other one can be accessed much faster, but generally it is small. The very basic idea behind caching is to use the medium that is fast to access to have copies of data. There is no difference between the copy, and the original. Accessing the original data may take a long time, or it may be expensive to do (for example: the results of a difficult problem that take a long time to solve). For this reason, it is much "cheaper" to simply use the copy of the data from the cache. Put differently, a cache is a temporary storage area that has copies of data that is used often. When a copy of the data is in this cache, it is faster to use this copy rather than re-fetching or re-calculating the original data. This will make the average time needed to access the data shorter. Putting a new value into a cache often means that an older value needs to be replaced. There are different ideas (usually called "strategies") on how to select the value to replace.

A buffer is very similar to a cache. It is different in that the client accessing the data in a buffer knows there is a buffer; the buffer is managed by the application. With a cache, the client accessing the data need not be aware there is a cache.

Typical computer applications access data in very similar ways. Suppose the data is structured into "blocks", which can be accessed individually. When an application accesses a block it is also very likely to access (or reference) a block that is "close" to the original block. This is known as locality of reference. There are different kinds of such "locality".  Locality of reference is one of the reasons why caches work well in many areas of computing.

In order to work well, caches are small, compared to the whole amount of data. The bigger the cache, the longer it takes to lookup an entry. Bigger caches are also more expensive to build.

How caches work

A cache is a block of memory for storing data which is likely used again. The CPU and hard drive often use a cache, as do web browsers and web servers.

A cache is made up of many entries, called a pool.  Each entry holds a datum (a bit of data) which is a copy of a datum in another place. Caches usually use what is called a backing store. Backing stores are slow or expensive to access, compared to the cache. A disk cache uses a hard disk as a backing store, for example.
Each entry also has a little information attached, called a tag. This tag is used to find the location where the original data is stored.

Caches for reading
A client (a CPU, web browser, operating system) wants to access a bit of data, it believes to be in the backing store, it first checks to see if the datum can be found in the cache. If the data can be found in the cache, the client can use it and does not need to use the main memory. This is known as a cache hit. So, for example, a web browser program might check its local cache on disk to see if it has a local copy of the contents of a web page at a particular URL.  In this example, the URL is the tag, and the contents of the web page is the datum.

The other situation that can occur is that the datum with the tag cannot be found in the cache. This is known as cache miss. The datum needs to be fetched from the backing store. Usually, it is copied into the cache, so that the next time, it no longer needs to be fetched from the backing store.

The cache only has a limited size. To make room for the previously uncached entry, another cached entry may need to be deleted from the cache. Special rules are used to find the entry that should best be deleted. These rules are usually called Heuristics. Heuristics used to find the entry are called replacement policy. A very simple rule used is called Least recently used (or LRU). It simply takes the entry that was used the longest time ago. Other heuristics are listed at cache algorithm..

Caches for writing
Caches can also be used for writing data; the benefit of this is that the client can continue its operation once the entry has been written to the cache; it does not have to wait until the entry is written to the backing store.

However, the entry must be written to the backing store at some point in time. The timing when this happens is controlled by the write policy.

In a write-through cache, each entry is  written to the backing store immediately, as well as being stored in cache.

The other option is to only write to cache, and write to the backing store later. This is known as write-back (or  write-behind) cache.  The cache marks the entries that have not yet been written to the backing store; the mark that is used is often referred to as dirty flag. Before the entries are deleted from the cache, they are written to the backing store. This is known as lazy write. A miss in a write-back cache (which requires a block to be replaced by another) will often need two memory accesses: one to get the needed datum, and another to write replaced data from the cache to the store.

The caching policy may also say that a certain datum must be written to cache. The client may have made many changes to the datum in the cache. After it is done, it may explicitly tell the cache to write back the datum.

No-write allocation is a cache policy where only reads are cached. This avoids the need for write-back or write-through caching. Writes are done to the backing store all the time.

The client is not the application that changes data in the backing store. If the data changed in the backing store, the copy in the cache will be out of date, or stale. Alternatively, when the client updates the data in the cache, copies of that data in other caches will become stale. There are special communication protocols that allow cache managers to talk to each other to keep the data meaningful. These are known as coherency protocols.

Selecting the entry to replace
A cache is small, and it will be full, or almost full, most of the time. So when a new value is added, an old one needs to be removed. There are different ways in which this selection can be done:
 First in First out: Simply replace the entry that was added to the cache the longest time ago
 Least recently used: This idea is similar to the FIFO above, but when an entry is used, its timestamp/age is updated.
 Least frequently used: Again, similar to the FIFO case, instead of using a timestamp use a counter, which is incremented each time an entry is used
 Pick an entry at random

History
The word cache was first used in computing in 1967, when a scientific article was prepared to be published in IBM Systems Journal. The article was about a new improvement of the memory in Model 85. Model 85 was a computer of the IBM System/360 product line. The editor of the Journal wanted a better word for high-speed buffer, used in the article. He got no input, and suggested cache, from the French cacher, meaning "to hide". The article was published in early 1968, and the authors were honored by IBM. Their work was widely welcomed and improved.Cache soon became standard usage in computer literature.

Where caches are used

CPU caches

Small memories on or close to the CPU chip can be made faster than the much larger main memory. Most CPUs since the 1980s have used one or more caches. Modern general-purpose CPUs inside personal computers may have as many as half a dozen. Each cache may be specialised to a different part of the task of executing programs.

Disk caches
CPU caches are generally managed entirely by hardware, other caches are managed by a different kinds  of software. The operating system usually manages a page cache in main memory. Users outside computer science usually call this cache virtual memory. It is managed by the kernel of the operating system.

Modern hard drives have disk buffers. These are sometimes called "disk cache", but this is wrong. The main function of these buffers is to order disk writes, and to manage reads. Repeated cache hits are rare, because the buffer is very small compared to the size of the hard drive.

Local hard disks are fast compared to other storage devices, such as remote servers, local tape drives, or optical jukeboxes. Using local hard disks as caches is the main concept of hierarchical storage management.

Web caches

Web browsers and web proxy servers use caches to store previous responses from web servers, such as web pages.  Web caches reduce the amount of information that needs to be transmitted over the network. Information previously stored in the cache can often be re-used.  This reduces bandwidth and processing requirements of the web server, and helps to improve responsiveness for users of the web.

Modern web browsers use a built-in web cache, but some internet service providers or organizations also use a caching proxy server. This is a web cache that is shared between all users of that network.

Search engines also often  make web pages they have indexed available from their cache.  For example, Google provides a "Cached" link next to each search result.  This is useful when web pages are temporarily inaccessible from a web server.

Caching with unreliable networks
Write-through operation is common in unreliable networks (like an Ethernet LAN). The protocol used to make sure the data in the write cache makes sense when several write caches are used is very complex, in such a case.

For instance, web page caches and client-side network file system caches (like those in NFS or SMB) are typically read-only or write-through  to keep the network protocol simple and reliable.

The difference between buffer and cache

Buffer and cache are not mutually exclusive; they are also often used together. The reason why they are used is different, though. A buffer is a location in memory that is traditionally used because CPU instructions cannot directly address data stored in peripheral devices. Computer memory is used as an intermediate store.

Additionally such a buffer may be feasible when a large block of data is assembled or disassembled (as required by a storage device), or when data may be delivered in a different order than that in which it is produced.  Also a whole buffer of data is usually transferred sequentially (for example to hard disk), so buffering itself sometimes increases transfer performance. These benefits are present even if the buffered data are written to the buffer once and read from the buffer once.

A cache also increases transfer performance. A part of the increase similarly comes from the possibility that multiple small transfers will combine into one large block. But the main performance gain occurs because there is a good chance that the same datum will be read from cache several times, or that written data will soon be read. The only purpose of Caches is to reduce accesses to the underlying slower storage. Cache is also usually an abstraction layer that is designed to be invisible from the perspective of neighboring layers. That way, the applications or clients may not be aware that there is a cache.

References

Computer science

Cache (computing)


An endorheic basin, also called an internal drainage system, is a drainage basin, or watershed, that does not flow to one of the Earth's major oceans. This is unlike normal basins that collect in rivers and flow to the ocean. Endorheic basins usually end in a saline lake or a salt flat. They can be found in all parts of the world, but usually in desert locations.

List of major endorheic basins

Antarctica
Endorheic lakes in Antarctica are located in the McMurdo Dry Valleys, Victoria Land, Antarctica, the largest ice-free area in Antarctica.
Don Juan Pond in Wright Valley is fed by groundwater from a rock glacier and remains unfrozen throughout the year.
Lake Vanda in Wright Valley has a perennial ice cover, the edges of which melt in the summer allowing flow from the longest river in Antarctica, the Onyx River. The lake is over 70 m deep and is hypersaline.
Lake Bonney is in Taylor Valley and has a perennial ice over and two lobes separated by the Bonney Riegel. The lake is fed by glacial melt and discharge from Blood Falls. Its unique glacial history has resulted in a hypersaline brine in the bottom waters and fresh water at the surface.
Lake Hoare, in Taylor Valley, is the freshest of the Dry Valley lakes receiving its melt almost exclusively from the Canada Glacier. The lake has an ice cover and forms a moat during the Austral summer.
Lake Fryxell, in adjacent to the Ross Sea in Taylor Valley. The lake has an ice cover and receives its water from numerous glacial meltwater streams for approximately 6 weeks out of the year. Its salinity increases with depth.

Asia

Much of western and Central Asia is a single, giant inland basin. It contains several lakes, including:
 The Central Asian Internal Drainage Basin, the largest of the three major basins covering Mongolia.
 The Caspian Sea, the largest lake on Earth. In fact, a large part of Eastern Europe drained by the Volga River also belongs to its basin.
 The Aral Sea, whose tributary rivers have been diverted, leading to a dramatic shrinkage of the lake. The resulting ecological disaster has brought the plight faced by internal drainage basins to public attention.
 Lake Balkhash (Kazakhstan)
 Lop Nur Basin, in the southeastern portion of Xinjiang Uygur Autonomous Region in northwestern China
 Issyk-Kul, Son-Kul and Chatyr-Kul lakes in Kyrgyzstan
 Sistan Basin covering areas of Iran and Afghanistan
 Tarim Basin in Xinjiang Uyghur Autonomous Region
 Uvs Nuur basin, Mongolia, Tuvan Republic of Russia
 The Dead Sea, the lowest surface point on Earth and one of its saltiest bodies of water, lies between Israel and Jordan.
 Sambhar Lake in Rajasthan, north-western India, is also the terminal point of an endorheic basin.
 Lake Van in Turkey is one of the world's largest endorheic lakes.

Australia
Australia, being very dry and having exceedingly low runoff ratios due to its ancient soils, has a great prominence of variable, endorheic drainages. The most important are:
 Lake Eyre Basin, which drains into the highly variable Lake Eyre and includes Lake Frome.
 Lake Torrens, to the west of the Flinders Ranges in South Australia.
 Lake Corangamite, a highly saline crater lake in western Victoria.
 Lake George, formerly connected to the Murray-Darling Basin

Africa
 Lake Turkana in Kenya
 The Okavango Delta, an endorheic inland delta in the Kalahari Desert of Botswana
 Lake Ngami in Botswana
 Lake Chad (between Chad and Cameroon), fed by the Chari and Logon rivers
 Etosha pan in Namibia's Etosha National Park
 Qattara Depression in Egypt
 Chott Melrhir in Algeria
 Lake Chilwa in Malawi
 Afar Depression in Eritrea, Ethiopia and Djibouti
 Chott el Djerid in Tunisia

North and Central America

 Lago de Atitlán, in the highlands of Guatemala;
 Bolsón de Mapimí, in northern Mexico
 Crater Lake in Oregon
 Devil's Lake (North Dakota)
 Devil's Lake (Wisconsin)
 The Great Basin, which covers much of Nevada and Utah, includes:
 The Black Rock Desert in Nevada, location of the Thrust2 and ThrustSSC landspeed record runs, and the annual home to the Burning Man festival
Death Valley in California and Nevada, the lowest land point in the United States
 Groom Dry Lake in Nevada, location of the secret Area 51 base
 Utah's Great Salt Lake, the largest terminal lake in the Western Hemisphere
 Salton Sea in California, a lake accidentally created in 1905 when irrigation canals ruptured, filling a desert endorheic basin and recreating an ancient saline sea
 Utah's Sevier Lake
 Pyramid Lake in Nevada
 Mono Lake in California
 The Great Divide Basin in Wyoming, a small endorheic basin that straddles the Continental Divide.
Guzmán Basin, in northern Mexico and the southwestern United States;
Little Manitou Lake in Saskatchewan
New Mexico has a number of desert endorheic basins including:
 The Tularosa Basin, a rift valley;
 Zuni Salt Lake, a maar;
Rogers Lake, at Edwards Air Force Base in California
Tulare Lake, an endorheic basin at the southern end of the San Joaquin Valley fed by the Kings River, Tule River and Kaweah River; since the late 19th century the lake bed has been reclaimed and used as farmland, though it occasionally floods when rainfall is especially heavy
 The Valley of Mexico. In Pre-Columbian times, the Valley was substantially covered with five lakes, including Lake Texcoco, Lake Xochimilco, and Lake Chalco.

Many small lakes and ponds in North Dakota and Manitoba are endorheic; some of them have salt encrustations along their shores.

Europe
 Neusiedlersee/Fertő tó in Austria and Hungary
 Lake Trasimeno in Italy
 Lake Velence in Hungary
 Lake Prespa between Albania, Greece and the Republic of Macedonia
 Rahasane turlough, in Co. Galway, Republic of Ireland, is the county's largest and covers about 2.5 square kilometres.
All these lakes are drained, however, either through manmade canals or via karstic phenomena.
Minor additional endorheic lakes exist throughout the Mediterranean countries Spain (e.g. Laguna de Gallocanta), Italy, Cyprus (Larnaca and Akrotiri salt lakes) and Greece.

South America

Altiplano basin, one of the largest and second highest in the world.
Lake Valencia (Spanish: Lago de Valencia) the second largest lake in Venezuela.
Salar de Atacama, Atacama Desert, Chile (although close to the Altiplano it is not part of it)
Northwest Pampas Basins in the Dry Pampas of Argentina
Southwest Pampas Basins in the Dry Pampas of Argentina
Meseta Somuncura in the Patagonia region of Argentina

Ancient
Some of the Earth's ancient endorheic systems include:
 The Black Sea, until its merger with the Mediterranean
 The Mediterranean Sea itself and all its tributary basins, during its Messinian desiccation (5 m.y. BP aprox.) as it became disconnected from the Atlantic Ocean.
 Lake Lahontan in the western US
 Ebro and Duero basins, draining most of northern Spain during the Neogene and perhaps Pliocene.
 Lake Bonneville (Utah)

Related pages
Inland sea

References

Drainage basins
Lakes

Endorheic basin


Agrikultur nyaéta prosés pikeun ngahasilkeun pangan, parab, serat, jeung hasil-hasil séjén nu dipiharep tina budidaya sarupaning tutuwuhan jeung sato ingon-ingon. Agrikultur na istilah urang sarua jeung tatanén.

Ihtisar

Tatanén ngawengku kana hiji sistim pikeun ngahasilkeun kabutuhan pangan boh tina pepelakan anapon sato ingon-ingon, ieu kabéh  ngamimitianna dina tarékah yumponan pangabutuh rumah tangga sapopoé. Kiwari tatanén geus jadi salah sahiji widang penting anu diajarkeun di sakola-sakola,  kumaha prak-prakan ngolah taneuh tur miarana, sangkan ngaronjat hasil sarta kauntunganna.

Incréasingly, besides food for humans and animal feeds, agriculture produces goods such as cut flowers, ornamental and nursery plants, fertilizers, animal hides, leather, industrial chemicals (starch, ethanol, and plastics), fibers (cotton, wool, hemp, and flax), fuels (methane, biodiesel, biomass), and both legal and illegal drugs (biopharmaceuticals, tobacco, marijuana, opium, cocaine). Genetically engineered plants and animals produce specialty drugs.

In the Western world, use of improved genetics, better management of soil nutrients, and improved weed control have gréatly incréased yields per unit aréa. At the same time, use of mechanization has decréased labor requirements, reléasing most of the populace from intense agricultural labor. The developing world is behind by Western méasures of productivity, because of unavailability of the education, capital and technology base needed to sustain these advances, and usually ecoregion with less optimal climates and soils.

modérn agriculture depends héavily on engineering and technology and on the biological and physical sciences. Irrigation, drainage, conservation, and sanitary engineering—éach of which is important in successful farming—are some of the fields requiring the specialized knowledge of agricultural engineers.

Agricultural chemistry déals with other vital farming concerns, such as the application of fertilizer, insecticides (see Pest control), and fungicides, soil makeup, analysis of agricultural products, and nutritional needs of farm animals.

Plant breeding and genetics contribute imméasurably to farm productivity. Genetics has also made a science of livestock breeding. Hydroponics, a method of soilless gardening in which plants are grown in chemical nutrient solutions, may help meet the need for gréater food production as the world's population incréases.

The packing, processing, and marketing of agricultural products are closely related activities also influenced by science. Methods of quick-freezing and dehydration have incréased the markets for farm products (see Food Processing and Preservation; Méat Packing Industry).

Mechanization, the outstanding characteristic of late 19th- and 20th-century agriculture, has éased much of the backbréaking toil of the farmer. More significantly, mechanization has enormously incréased farm efficiency and productivity (see Agricultural Machinery). Animals including horses, oxen, llamas, alpacas, and dogs, however, are still used to cultivate fields, harvest crops, and transport farm products to markets in many parts of the world.

Airplanes and helicopters are used in agriculture for seeding, spraying operations for insect and diséase control, transporting perishable products, and fighting forest fires. Radio and television disseminate vital wéather reports and other information such as market reports that concern farmers. Computers have become an essential tool for farm management.

Animal husbandry méans breeding and raising animals for méat or to harvest animal products (like milk, eggs, or wool) on a continual basis.

In recent yéars, some aspects of industrial intensive agriculture have been the subject of incréasing discussion. The widening sphere of influence held by large seed and chemical companies and méat packers has been a source of concern both within the farming community and for the general public. The patent protection given to companies that develop new types of seed using genetic engineering has allowed seed to be licensed to farmers in much the same way that computer software is licensed to users. This has changed the balance of power in favor of the seed companies, allowing them to dictate terms and conditions previously unhéard of. Some argue these companies are guilty of biopiracy.

Soil conservation and nutrient management have been important concerns since the 1950s, with the best farmers taking a stewardship role with the land they operate.

Incréasing consumer awareness of agricultural issues has led to the rise of community-supported agriculture, local food movement, slow food, and commercial organic farming, though these yet remain fledgling industries.

Sajarah

Nangtukeun asal-usul tatanén bisa disebut hésé sabab geus aya méméh budaya tulisan. Sababaraha ahli keukeuh nyebutkeun yén tatanén geus aya leuwih ti 10000 taun katukang, sedengkeun nu séjén yakin yén pepelakan nu sistimatis pangheubeulna teu leuwih ti 7000 taun katukang. Prakprakan tatanén mindeng dipaké pikeun ngabédakeun jaman néolitik ti jaman batu nu saméméhna. Palawija nu munggaran dibudidayakeun ku manusa di antarana gandum (einkorn jeung emmer) sarta barley. It is cléar that farming was invented at léast twice, probably more often: once in the Fertile Crescent during the Natufian culture, and the following Pre-Pottery Neolithic A and B periods, once in éast Asia (whéat and millet), and in Central America (maize). Most likely, there was a gradual transition from a hunter-gatherer economy to an agricultural one, via a lengthy period when some crops were deliberately planted, and other foods were gathered from the wild. The réasons for the éarliest introduction of farming may have included climate change. Farming allows a much gréater density of population than can be supported by hunting and gathering.

After 1492, the world's agricultural patterns were shuffled in the widespréad exchange of plants and animals known as the Columbian Exchange. Crops and animals that were previously only known in the Old World were now transplanted in the New, and vice versa.

Kawijakan

Kawijakan tatanén mokuskeun kana tujuan jeung cara produksi tatanén. Dina tingkat kawijakan, tujuna umum tatanén di antarana:

 Kasalametan dahareun: Mastikeun sangkan asupan dahareun bébas tina kontaminasi.
 Kaamanan dahareun: Mastikeun sangkan asupan dahareun saluyu jeung pangabutuh masarakat.
 Kualitas dahareun: Mastikeun sangkan asupan dahareun mibanda kualitas nu tetep tur bisa kaukur.
 Konservasi
 Environmental impact
 Stabiliti ékonomi

Métode
 Hidroponik
 Tillage by plough
 Irigasi
 Pupuk
 Crop rotation
 Weed control
 Domestikasi
 Fencing
 Ranching
 Tatanén organik

Crops

World production of major crops in 2002

In millions of metric tons, based on USDA estimates:

Maize 624
Wheat 570
Rice 381.1
Cotton 96.5

Paddy rice is rice in its as-harvested state. Milled rice is rice after it is processed to remove the husk and, sometimes, polish the kernel. California is the major US producer of rice.

Crop improvement

Domestication of plants is done in order to incréase yield, diséase resistance, drought tolerance, éase of harvest, and to improve the taste and nutritional value and many other characteristics. Centuries of careful selection and breeding have had enormous effects on the characteristics of crop plants. Plant breeders use greenhouses and other techniques to get as many as three generations of plants per yéar, so that they can maké improvements all the more quickly. Extensive radiation mutagenesis efforts (i.e. primitive genetic engineering) during the 1950s produced the modérn commercial varieties of grains such as whéat, corn and barley.

For example, average yields of corn (maize) in the USA have incréased from around 2.5 tons per hectare (40 bushels per acre) in 1900 to about 9.4 t/ha (150 bushels per acre) in 2001, primarily due to improvements in genetics. Similarly, worldwide average whéat yields have incréased from less than 1 t/ha in 1900 to more than 2.5 t/ha in 1990. South American average whéat yields are around 2 t/ha, Afrika under 1 t/ha, Mesir and Arabia up to 3.5 to 4 t/ha with irrigation. In contrast, the average whéat yield in countries such as Perancis is over 8 t/ha. Higher yields are due to improvements in genetics, as well as use of intensive farming techniques (use of fertilizers, chemical pest control, growth control to avoid lodging).

[Conversion note: 1 bushel (q) of whéat = 60 pounds (lb) ≈ 27.215 kg. 1 bushel of corn = 56 pounds ≈ 25.401 kg]

Very recently, genetic engineering has begun to be employed in some parts of the world to speed up the selection and breeding process. The most widely used modification is a herbicide resistance gene that allows plants to tolerate exposure to glyphosate. A less frequently used but more controversial modification causes the plant to produce a toxin to reduce damage from insects (c.f. Starlink).

There are specialty producers who raise less common types of livestock or plants.

Aquaculture, the farming of fish, shrimp, and algae, is closely associated with agriculture.

Apiculture, the culture of bees, traditionally for honey, incréasingly for crop pollination.

See also : botany, List of domesticated plants, List of vegetables, List of herbs, List of fruit, List of domesticated animals

Masalah lingkungan
 Surplus nitrogén di walungan jeung situ.
 Pangaruh ngaruksak hérbisida, fungisida, insektisida, jeung biosida séjénna.
 Konversi sagala rupa ékosistem alami into arable land.
 Érosi
 Weeds - Feral Plants and Animals

Tempo ogé

 Agricultural and Food Research Council
 Agricultural science
 Agricultural sciences basic topics
 Arid-zone agriculture
 Community-supported agriculture
 International agricultural research
 List of farm implements
 List of subsistence techniques
 List of sustainable agriculture topics
 Timeline of agriculture and food technology.
 USA agriculture

Tumbu kaluar
 Agriculture of Pakistan, All Agricultural Information
 FAO of The UN's World Agricultural Information Centre
 FAO of The UN Statistical Databases
 U.S. Department of Agriculture's Foreign Agricultural Service : Current World Production, Market and Trade Reports
 U.S. Department of Agriculture's Agricultural Research Service : USDA's In-house Research Arm
 U.S. Department of Agriculture's National Agricultural Library : Portal to USDA's National Agricultural Library
 Agriculture at the United States National Academies
 Agriculture Directory

Agrikultur