On 13th June, 2005 , the Prime Minister of India, Dr. Manmohan Singh, constituted the National Knowledge Commission, as a think-tank charged with considering possible policy that might sharpen India's comparative advantage in the knowledge-intensive service sectors.

In particular, the Commission was to advise the Prime Minister's Office on policy related to education, research institutes and reforms needed to make India competitive in the knowledge economy.
The Commission was to recommend reform of the education sector, research labs, and intellectual property legislation; as well as consider whether the Government could itself upgrade its use of the latest techniques to make its workings more transparent.

The NKC website was launched in February 2006.

राष्ट्रीय ज्ञान आयोग के कार्य

The National Knowledge Commission (NKC) consists of the following seven members.

सैम पित्रोदा, अध्यक्ष,
अशोक गांगुली, कारपोरेट अध्यक्ष
नंदन नीलकेणी, इनफोसिस,
डॉ. दीपक नैय्यर, पूर्व उपकुलपति, दिल्ली विश्वविद्यालय
डॉ. ज्योति घोष, अर्थशास्त्री जवाहरलाल नेहरू विश्वविद्यालय
डॉ. सुजाता रामदोराई, टीआईएफ़ाआर
डॉ. पी बलराम, भारतीय विज्ञान संस्थान, बंगलोर

The Terms of Reference of the NKC are:

 "Build excellence in the educational system to meet the knowledge challenges of the 21st century and increase India's competitive advantage in fields of knowledge.
 Promote creation of knowledge in Science and technology laboratories.
 Improve the management of institutions engaged in Intellectual Property Rights.
 Promote knowledge applications in Agriculture and Industry.
 Promote the use of knowledge capabilities in making government an effective, transparent and accountable service provider to the citizen and promote widespread sharing of knowledge to maximize public benefit."

The organisational structure of the NKC is flat. The Secretariat is headed by an Executive Director and consists of around 8-9 research associates. It also has four advisors who advises the commission on different issues. The Secretariat of the Commission is located in Chanakyapuri, New Delhi.

In December 2006, the Commission brought out a 'Report to the Nation 2006'. It includes the following recommendations submitted to the Prime Minister:

 पुस्तकालय,
 ज्ञान नेटवर्क,
 ई-प्रशासन,
 अनुवाद,
 भाषाएँ,
 राष्ट्रीय जालस्थल

Many of the recommendations of the NKC are already in the implementation stage by different ministries of the Government. This includes areas such as Libraries, e-governance and translation.

Some of the major areas under work are higher education, vocational education, entrepreneurship, school education etc.

The NKC consults a wide range of stake-holders and experts on each area before submitting the recommendations to the Prime Minister. Each area has a working group which is headed by a prominent person in that field. The Working Group members meet several times to submit a report to the NKC. The NKC members then hold discussions on the report before submitting it to the Prime Minister. After submitting the recommendations, an extensive coordination also takes place with the Planning Commission of India and relevant ministries of the Government.

As many of the components of the education sector remains state subjects in India, NKC representatives also visit various state governments and conduct deliberations with secretaries of education departments for reforming of the education sector at the state level.

The Commission is mandated to last till October 2008.

विवाद

Since its inception, the commission has been surrounded by different controversies.

In May 2006 the Commission spoke out against the Human Resource Development Ministry's plans to increase quotas for backward castes in institutions such as the IITs. Following Arjun Singh's subsequent remarks on their credentials, two of the members, Andre Béteille and  Dr Pratap Bhanu Mehta, sent letters of resignation to the Prime Minister.

A difference of opinion also took place between Dr. P.M.Bhargava and rest of the commission members in early 2007, which resulted in reconstitution of the commission.

बाहरी कड़ियाँ
 http://knowledgecommission.gov.in/hindi/default.asp

श्रेणी:भारत सरकार

રાષ્ટ્રીય જ્ઞાન આયોગ


The Honda XRM is an unnerbone-style motorbike that is produced an sauld in the Philippines. It is cawed Nice in Thailand but no an Aff-Road type. Since 2001, the Honda XRM haes been released wi a 110 cc ingine, but 2007 haes seen the release o the Honda XRM 125 cc which uises the ingine frae the Honda Wave. It is designed for baith on- an aff-road uise.

Ease o modification an readily-available pairts an accessories hae made the Honda XRM popular, particularly wi unnerbone ridin cultur, wi numerous rider clubs being formed athort the kintra. Unfortunately, these modifications (especially tae the handlebars an wheels) coud pose dangers, as they are no specifically includit in the product's ingineerin, an aften defeat the "Dual-Sport" nature o the motorbike.

The Honda Bravo is a derivative o the Honda XRM designed for ceety uise, but it carries the same frame that is uised bi NF100 (Wave100 - baith models) no the frame o the XRM.

References

External links
Honda Philippines Website
Honda Philippines XRM Webpage

XRM

Honda XRM


In electromagnetism, skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor. The electric current flows mainly at the "skin" of the conductor, between the outer surface and a level called the skin depth. Skin depth depends on the frequency of the alternating current; as frequency increases, current flow becomes more concentrated near the surface, resulting in less skin depth. Skin effect reduces the effective cross-section of the conductor and thus increases its effective resistance. It is caused by opposing eddy currents induced by the changing magnetic field resulting from the alternating current. At 60 Hz in copper, skin depth is about 8.5 mm. At high frequencies skin depth becomes much smaller.

Increased AC resistance caused by skin effect can be mitigated by using a specialized multistrand wire called litz wire. Because the interior of a large conductor carries little of the current, tubular conductors can be used to save weight and cost. Skin effect has practical consequences in the analysis and design of radio-frequency and microwave circuits, transmission lines (or waveguides), and antennas. It is also important  at mains frequencies (50–60 Hz) in AC electric power transmission and distribution systems.  It is one of the reasons for preferring high-voltage direct current for long distance power transmission.

The effect was first described in a paper by Horace Lamb in 1883 for the case of spherical conductors, and was generalized to conductors of any shape by Oliver Heaviside in 1885.

Cause

Conductors, typically in the form of wires, may be used to transmit electrical energy or signals using an alternating current flowing through that conductor. The charge carriers constituting that current, usually electrons, are driven by an electric field due to the source of electrical energy. A current in a conductor produces a magnetic field in and around the conductor.  When the intensity of current in a conductor changes, the magnetic field also changes.  The change in the magnetic field, in turn, creates an electric field which opposes the change in current intensity.  This opposing electric field is called "counter-electromotive force" (back EMF).  The back EMF is strongest at the center of the conductor, allowing current only near the outside skin of the conductor, as shown in the diagram on the right.

Regardless of the driving force, the current density is found to be greatest at the conductor's surface, with a reduced magnitude deeper in the conductor. That decline in current density is known as the skin effect and the skin depth is a measure of the depth at which the current density falls to 1/e of its value near the surface.
Over 98% of the current will flow within a layer 4 times the skin depth from the surface. This behavior is distinct from that of direct current which usually will be distributed evenly over the cross-section of the wire.

An alternating current may also be induced in a conductor due to an alternating magnetic field according to the law of induction. An electromagnetic wave impinging on a conductor will therefore generally produce such a current; this explains the reflection of electromagnetic waves from metals. Although the term "skin effect" is most often associated with applications involving transmission of electric currents, skin depth also describes the exponential decay of the electric and magnetic fields, as well as the density of induced currents, inside a bulk material when a plane wave impinges on it at normal incidence.

Formula
The AC current density  in a conductor decreases exponentially from its value at the surface
according to the depth  from the surface, as follows:

where  is called the skin depth which is defined as the depth below the surface of the conductor at which the current density has fallen to 1/e (about 0.37) of S. The imaginary part of the exponent indicates that the phase of the current density is delayed 1 radian for each skin depth of penetration. One full wavelength in the conductor requires 2 skin depths, at which point the current density is attenuated to e−2 (1.87×, or −54.6 dB) of its surface value. The wavelength in the conductor is much shorter than the wavelength in vacuum, or equivalently, the phase velocity in a conductor is very much slower than the speed of light in a vacuum. For example, a 1 MHz radio wave has a wavelength in vacuum  of about 300 m, whereas in copper, the wavelength is reduced to only about 0.5 mm with a phase velocity of only about 500 m/s. As a consequence of Snell's law and this very tiny phase velocity in a conductor, any wave entering a conductor, even at grazing incidence, refracts essentially in the direction perpendicular to the conductor's surface.

The general formula for skin depth when there is no dielectric or magnetic loss is:

where

At frequencies much below  the quantity inside the large radical is close to unity and the formula is more usually given as:

This formula is valid at frequencies away from strong atomic or molecular resonances (where  would have a large imaginary part) and at frequencies that are much below both the material's plasma frequency (dependent on the density of free electrons in the material) and the reciprocal of the mean time between collisions involving the conduction electrons. In good conductors such as metals all of those conditions are ensured at least up to microwave frequencies, justifying this formula's validity. For example, in the case of copper, this would be true for frequencies much below .

However, in very poor conductors, at sufficiently high frequencies, the factor under the large radical increases. At frequencies much higher than  it can be shown that skin depth, rather than continuing to decrease, approaches an asymptotic value:

This departure from the usual formula only applies for materials of rather low conductivity and at frequencies where the vacuum wavelength is not much larger than the skin depth itself. For instance, bulk silicon (undoped) is a poor conductor and has a skin depth of about 40 meters at 100 kHz ( = 3 km). However, as the frequency is increased well into the megahertz range, its skin depth never falls below the asymptotic value of 11 meters. The conclusion is that in poor solid conductors, such as undoped silicon, skin effect doesn't need to be taken into account in most practical situations: Any current is equally distributed throughout the material's cross-section, regardless of its frequency.

Current density in a round conductor

When skin depth is not small with respect to the radius of the wire, current density may be described in terms of Bessel functions.  The current density inside round wire away from the influences of other fields, as function of distance from the axis is given by:

where

Since  is complex, the Bessel functions are also complex.  The amplitude and phase of the current density varies with depth.

Impedance of round wire

The internal impedance per unit length of a segment of round wire is given by:

This impedance is a complex quantity corresponding to a resistance (real) in series with the reactance (imaginary) due to the wire's internal self-inductance, per unit length.

Inductance

A portion of a wire's inductance can be attributed to the magnetic field inside the wire itself which is termed the internal inductance; this accounts for the inductive reactance (imaginary part of the impedance) given by the above formula. In most cases this is a small portion of a wire's inductance which includes the effect of induction from magnetic fields outside of the wire produced by the current in the wire. Unlike that external inductance, the internal inductance is reduced by skin effect, that is, at frequencies where skin depth is no longer large compared to the conductor's size. This small component of inductance approaches a value of  (50 nH/m for non-magnetic wire) at low frequencies, regardless of the wire's radius. Its reduction with increasing frequency, as the ratio of  skin depth to the wire's radius falls below about 1, is plotted in the accompanying graph, and accounts for the reduction in the telephone cable inductance with increasing frequency in the table below.

Resistance
The most important effect of skin effect on the impedance of a single wire is the increase of the wire's resistance, and consequent losses. The effective resistance due to a current confined near the surface of a large conductor (much thicker than ) can be solved as if the current flowed uniformly through a layer of thickness  based on the DC resistivity of that material. The effective cross-sectional area is approximately equal to  times the conductor's circumference.
Thus a long cylindrical conductor such as a wire, having a diameter  large compared to , has a resistance approximately that of a hollow tube with wall thickness  carrying direct current. The AC resistance of a wire of length  and resistivity  is:

The final approximation above assumes .

A convenient formula (attributed to F.E. Terman) for the diameter  of a wire of circular cross-section whose resistance will increase by 10% at frequency  is:

This formula for the increase in AC resistance is accurate only for an isolated wire. For nearby wires, e.g. in a cable or a coil, the AC resistance is also affected by proximity effect, which can cause an additional increase in the AC resistance.

Material effect on skin depth

In a good conductor, skin depth is proportional to square root of the resistivity.  This means that better conductors have a reduced skin depth.  The overall resistance of the better conductor remains lower even with the reduced skin depth. However the better conductor will show a higher ratio between its AC and DC resistance, when compared with a conductor of higher resistivity. For example, at 60 Hz, a 2000 MCM (1000 square millimeter) copper conductor has 23% more resistance than it does at DC.  The same size conductor in aluminum has only 10% more resistance with 60 Hz AC than it does with DC.

Skin depth also varies as the inverse square root of the permeability of the conductor.  In the case of iron, its conductivity is about 1/7 that of copper.  However being ferromagnetic its permeability is about 10,000 times greater.  This reduces the skin depth for iron to about 1/38 that of copper, about 220 micrometers at 60 Hz.  Iron wire is thus useless for AC power lines (except to add mechanical strength by serving as a core to a non-ferromagnetic conductor like aluminum). Skin effect also reduces the effective thickness of laminations in power transformers, increasing their losses.

Iron rods work well for direct-current (DC) welding but it is impossible to use them at frequencies much higher than 60 Hz.  At a few kilohertz, the welding rod will glow red hot as current flows through the greatly increased AC resistance resulting from skin effect, with relatively little power remaining for the  arc itself.  Only non-magnetic rods can be used for high-frequency welding.

At 1 megahertz skin effect depth in wet soil is about 5.0 m; in seawater it is about 0.25 m.

Mitigation

A type of cable called litz wire (from the German Litzendraht, braided wire) is used to mitigate skin effect for frequencies of a few kilohertz to about one megahertz.  It consists of a number of insulated wire strands woven together in a carefully designed pattern, so that the overall magnetic field acts equally on all the wires and causes the total current to be distributed equally among them. With skin effect having little effect on each of the thin strands, the bundle does not suffer the same increase in AC resistance that a solid conductor of the same cross-sectional area would due to skin effect.

Litz wire is often used in the windings of high-frequency transformers to increase their efficiency by mitigating both skin effect and proximity effect.
Large power transformers are wound with stranded conductors of similar construction to litz wire, but employing a larger cross-section corresponding to the larger skin depth at mains frequencies.
Conductive threads composed of carbon nanotubes have been demonstrated as conductors for antennas from medium wave to microwave frequencies. Unlike standard antenna conductors, the nanotubes are much smaller than the skin depth, allowing full use of the thread's cross-section resulting in an extremely light antenna.

High-voltage, high-current overhead power lines often use aluminum cable with a steel reinforcing core; the higher resistance of the steel core is of no consequence since it is located far below the skin depth where essentially no AC current flows.

In applications where high currents (up to thousands of amperes) flow, solid conductors are usually replaced by tubes, completely eliminating the inner portion of the conductor where little current flows. This hardly affects the AC resistance, but considerably reduces the weight of the conductor. The high strength but low weight of tubes substantially increases span capability. Tubular conductors are typical in electric power switchyards where the distance between supporting insulators may be several meters. Long spans generally exhibit physical sag but this does not affect electrical performance. To avoid losses, the conductivity of the tube material must be high.

In high current situations where conductors (round or flat busbar) may be between 5 and 50 mm thick skin effect also occurs at sharp bends where the metal is compressed inside the bend and stretched outside the bend. The shorter path at the inner surface results in a lower resistance, which causes most of the current to be concentrated close to the inner bend surface. This causes an increase in temperature at that region compared with the straight (unbent) area of the same conductor. A similar skin effect occurs at the corners of rectangular conductors (viewed in cross-section), where the magnetic field is more concentrated at the corners than in the sides. This results in superior performance (i.e. higher current with lower temperature rise) from wide thin conductors (for example, "ribbon" conductors) in which the effects from corners are effectively eliminated.

It follows that a transformer with a round core will be more efficient than an equivalent-rated transformer having a square or rectangular core of the same material.

Solid or tubular conductors may be silver-plated to take advantage of silver's higher conductivity. This technique is particularly used at VHF to microwave frequencies where the small skin depth requires only a very thin layer of silver, making the improvement in conductivity very cost effective. Silver plating is similarly used on the surface of waveguides used for transmission of microwaves. This reduces attenuation of the propagating wave due to resistive losses affecting the accompanying eddy currents; skin effect confines such eddy currents to a very thin surface layer of the waveguide structure. Skin effect itself isn't actually combatted in these cases, but the distribution of currents near the conductor's surface makes the use of precious metals (having a lower resistivity) practical. Although it has a lower conductivity than copper and silver, gold plating is also used, because unlike copper and silver, it does not corrode. A thin oxidized layer of copper or silver would have a low conductivity, and so would cause large power losses as the majority of the current would still flow through this layer.

Recently, a method of layering non-magnetic and ferromagnetic materials with nanometer scale thicknesses has been shown to mitigate the increased resistance from skin effect for very high frequency applications. A working theory is that the behavior of ferromagnetic materials in high frequencies results in fields and/or currents that oppose those generated by relatively nonmagnetic materials, but more work is needed to verify the exact mechanisms. As experiments have shown, this has potential to greatly improve the efficiency of conductors operating in tens of GHz or higher. This has strong ramifications for 5G communications.

Examples

We can derive a practical formula for skin depth as follows:

where

Gold is a good conductor with a resistivity of  and is essentially nonmagnetic:  1, so its skin depth at a frequency of 50 Hz is given by

Lead, in contrast, is a relatively poor conductor (among metals) with a resistivity of , about 9 times that of gold. Its skin depth at 50 Hz is likewise found to be about 33 mm, or
 times that of gold.

Highly magnetic materials have a reduced skin depth owing to their large permeability  as was pointed out above for the case of iron, despite its poorer conductivity. A practical consequence is seen by users of induction cookers, where some types of stainless steel cookware are unusable because they are not ferromagnetic.

At very high frequencies skin depth for good conductors becomes tiny. For instance, skin depths of some common metals at a frequency of 10 GHz (microwave region) are less than a micrometer:

Thus at microwave frequencies, most of the current flows in an extremely thin region near the surface.  Ohmic losses of waveguides at microwave frequencies are therefore only dependent on the surface coating of the material. A layer of silver 3 μm thick evaporated on a piece of glass is thus an excellent conductor at such frequencies.

In copper, skin depth can be seen to fall according to the square root of frequency:

In Engineering Electromagnetics, Hayt points out that in a power station a busbar for alternating current at 60 Hz with a radius larger than one-third of an inch (8 mm) is a waste of copper, and in practice bus bars for heavy AC current are rarely more than half an inch (12 mm) thick except for mechanical reasons.

Skin effect reduction of the internal inductance of a conductor

Refer to the diagram below showing the inner and outer conductors of a coaxial cable. Since skin effect causes a current at high frequencies to flow mainly at the surface of a conductor, it can be seen that this will reduce the magnetic field inside the wire, that is, beneath the depth at which the bulk of the current flows. It can be shown that this will have a minor effect on the self-inductance of the wire itself; see Skilling or Hayt for a mathematical treatment of this phenomenon.

The inductance considered in this context refers to a bare conductor, not the inductance of a coil used as a circuit element. The inductance of a coil is dominated by the mutual inductance between the turns of the coil which increases its inductance according to the square of the number of turns. However, when only a single wire is involved, then in addition to the "external inductance" involving magnetic fields outside the wire (due to the total current in the wire) as seen in the white region of the figure below, there is also a much smaller component of "internal inductance" due to the portion of the magnetic field inside the wire itself, the green region in  figure B. That small component of the inductance is reduced when the current is concentrated toward the skin of the conductor, that is, when skin depth is not much larger than the wire's radius, as will become the case at higher frequencies.

For a single wire, this reduction becomes of diminishing significance as the wire becomes longer in comparison to its diameter, and is usually neglected. However the presence of a second conductor in the case of a transmission line reduces the extent of the external magnetic field (and of the total self-inductance) regardless of the wire's length, so that the inductance decrease due to skin effect can still be important. For instance, in the case of a telephone twisted pair, below, the inductance of the conductors substantially decreases at higher frequencies where skin effect becomes important. On the other hand, when the external component of the inductance is magnified due to the geometry of a coil (due to the mutual inductance between the turns), the significance of the internal inductance component is even further dwarfed and is ignored.

Inductance per length in a coaxial cable

Let the dimensions a, b, and c be the inner conductor radius, the shield (outer conductor) inside radius and the shield outer radius respectively, as seen in the crossection of figure A below.

For a given current, the total energy stored in the magnetic fields must be the same as the calculated electrical energy attributed to that current flowing through the inductance of the coax; that energy is proportional to the cable's measured inductance.

The magnetic field inside a coaxial cable can be divided into three regions, each of which will therefore contribute to the electrical inductance seen by a length of cable.

The inductance   is associated with the magnetic field in the region with radius , the region inside the center conductor.

The inductance   is associated with the magnetic field in the region , the region between the two conductors (containing a dielectric, possibly air).

The inductance   is associated with the magnetic field in the region , the region inside the shield conductor.

The net electrical inductance is due to all three contributions:

 is not changed by the skin effect and is given by the frequently cited formula for inductance L per length D of a coaxial cable:

At low frequencies, all three inductances are fully present so that .

At high frequencies, only the dielectric region has magnetic flux, so that  .

Most discussions of coaxial transmission lines assume they will be used for radio frequencies, so equations are supplied corresponding only to the latter case.

As skin effect increases, the currents are concentrated near the outside the inner conductor (r = a) and the inside of the shield (r = b). Since there is essentially no current deeper in the inner conductor, there is no magnetic field beneath the surface of the inner conductor. Since the current in the inner conductor is balanced by the opposite current flowing on the inside of the outer conductor, there is no remaining magnetic field in the outer conductor itself where  . Only  contributes to the electrical inductance at these higher frequencies.

Although the geometry is different, a twisted pair used in telephone lines is similarly affected: at higher frequencies the inductance decreases by more than 20% as can be seen in the following table.

Characteristics of telephone cable as a function of frequency

Representative parameter data for 24 gauge PIC telephone cable at .

More extensive tables and tables for other gauges, temperatures and types are available in Reeve.
Chen gives the same data in a parameterized form that he states is usable up to 50 MHz.

Chen gives an equation of this form for telephone twisted pair:

Anomalous skin effect
For high frequencies and low temperatures the usual formulas for skin depth break down. This effect was first noticed by Heinz London in 1940, who correctly suggested that it is due to the mean free path length of the electrons reaching the range of the classical skin depth. Mattis–Bardeen theory was developed for this specific case for metals and superconductors.

See also
 Proximity effect (electromagnetism)
 Penetration depth
 Eddy current
 Litz wire
 Transformer
 Induction cooking
 Induction heating
 Magnetic Reynolds number
 Wheeler incremental inductance rule, a method for estimating skin effect resistance

Notes

References

 Nahin, Paul J. Oliver Heaviside: Sage in Solitude. New York: IEEE Press, 1988. .
 Ramo, S., J. R. Whinnery, and T. Van Duzer. Fields and Waves in Communication Electronics. New York: John Wiley & Sons, Inc., 1965.

External links

Electromagnetism
Electrical parameters

Skin effect


Capsaicin is a chemical substance. It is responsible for the sense of spiciness or hotness found in chili peppers. In mammals, it causes a sensation of burning of the tissues it comes in contact with. Capsaicin, and other similar substances called capsaicinoids are produced by chili peppers and other plants, probably as a protection against being eaten. Pure capsaicin is a hydrophobic, colorless, odorless, crystalline to waxy compound.

Capsaicinoids are added to food to make it have a hot taste, but it can also be used as an analgesic, a painkiller. Such painkillers are often directly used on the skin. The burning of the capsaicin will mask the real pain. Capsaicin is also the main agent in pepper spray.

Capsaicin is not soluble in water; it binds to oil and fat. Soap can be used to wash it off. If something too hot has been eaten, milk or yoghurt can be used.

References

Organonitrogen compounds
Analgesics

Capsaicin


The scimitar babblers are birds in the genera Pomatorhinus and Jabouilleia of the large Old World babbler family of passerines. These are birds of tropical Asia, with the greatest number of species occurring in hills of the Himalayas.

Scimitar babblers are rangy, medium-sized, floppy-tailed land birds with soft fluffy plumage. They have strong legs and are quite terrestrial. This group is not strongly migratory, and most species have short rounded wings, and a weak flight.

Scimitar babblers have long, downward-curved bills, used to work through the leaf litter, which give the group its name. They are typically long tailed, dark brown above, and white or orange-brown below. Many have striking head patterns, with a broad black band through the eye, bordered with white above and below.

Most scimitar babblers are jungle species, difficult to observe in the dense vegetation they prefer, but like other babblers, these are noisy birds, and the characteristic bubbling calls are often the best indication that these birds are present.

As with other babbler species, they frequently occur in groups of up to a dozen, and the rain forest species like Indian scimitar babbler often occur in the mixed feeding flocks typical of tropical Asian jungle.

The genera are:

 Pomatorhinus - 15 species
 Jabouilleia - 2 species

References

Old World babblers
Timaliidae
Bird common names

Scimitar babbler


A series of méasurements of a process may be tréated as a deret waktu, and then trend estimation is the application of statistical techniques to maké and justify statements about trends in the data. Assuming the underlying process is a physical system that is incompletely understood, one may thereby construct a modél, independent of anything known about the physics of the process, to explain the behaviour of the méasurement. In particular, one may wish to know if the méasurements exhibit an incréasing or decréasing trend, that can be statistically distinguished from random behaviour. For example, take daily average temperatures at a given location, from winter to summer; or the global temperature series over the last 100 yéars.

Particularly in that latter case, issues of homogeneity (is the series equally reliable throughout its length?) are important. For the moment we shall simplify the discussion and neglect those points. This page does not attempt a full mathematical tréatment, merely an exposition.

Fitting a trend: least-squares

Given a set of data, and the desire to produce some kind of "model" of that data (modél, in this case, méaning a function fitted through the data) there are a variety of functions that can be chosen for the fit. But if there is no prior understanding of the data, the simplest function to fit is a straight line and thus this is the "default".

Continuing, once it has been decided to fit a straight line, there are various ways to do so, but the overwhelming default is the léast-squares fit, equivalent to minimisation of the L2 norm. See least squares.

Thus, given a set of data points , and data values , one choses  and  so that

is minimised. This can always be done, in closed form .

For the rest of this article, "trend" will méan the léast squares trend. It's what it méans in 99% of cases everywhere else.

Now, we have a trend. But is it significant? And what do we méan by significant?

Tren dina data random

saméméh urang nempo kana tren data riil, kudu ngarti heula tren dina data random.

If we take a series which is known to be random - fair dice falls; or computer-generated random numbers - and fit a trend line through the data, the chances of a truly zero trend are negligible. But we would probably expect the trend to be "small". If we take a series with a given degree of noise, and a given length (say, 100 points), and generate a large number of such series (say, 100,000 series), we can then calculate the trends from these 100,000 series, and empirically establish a distribution of trends that are to be expected from such random data - see diagram. Such a distribution will be normal (Central limit theorem except in pathological cases, since (in a slightly non-obvious way of thinking about it) the trend is a linéar combination of the ) and (if the series genuinely is random) centered on zero. We may now establish a level of statistical certainty, , desired - 95% confidence is typical; 99% would be stricter, 90% rather looser - and say: what value, , do we have to choose so that % of trends are within ? (complication: we may be interested in positive and negative trends - 2-tailed - or may have prior knowledge that only positive, or only negative, trends are of interest).

In the above discussion the distribution of trends was calculated empirically, from a large number of trials. In simple cases (normally distributed random noise being a classic) the distribution of trends can be calculated exactly.

Suppose we then take another series with approximately the same variance properties as our random series. We do not know in advance whether it "really" has a trend in it, so we calculate the trend, , and discover that it is less than . Then we may say that, at degree of certainty , any trend in the data cannot be distinguished from random noise.

However, note that whatever value of  we choose, then a given fraction, , of truly random series will be declared (falsely, by construction) to have a significant trend. Conversely, a certain fraction of series that "really" have a trend will not be declared to have a trend.

Data as trend plus noise

To analyse a (time) series of data, we assume that it may be represented as trend plus noise:

where  and  are (usually unknown) constants and the 's are independent randomly distributed "errors". Unless something special is known about the 's, they will be assumed to have a normal distribution. It is simplest if the 's all have the same distribution, but if not (if some have higher variance, méaning that those data points are effectively less certain) then this can be taken into account during the léast squares fitting, by weighting éach point by the inverse of the variance of that point.

In most cases, where only a single time series exists to be analysed, the variance of the 's is estimated by fitting a trend, thus allowing  to be removed and léaving the 's as residuals, and calculating the variance of the 's from the residuals — this is often the only way of estimating the variance of the 's.

One particular special case of gréat interest, the (global) temperature time series, is known not to be homogenéous in time: apart from anything else, the number of wéather observations has (generally) incréased with time, and thus the error associated with estimating the global temperature from a limited set of observations has decréased with time. In fitting a trend to this data, this can be taken into account, as described above.

Once we know the "noise" of the series, we can then assess the significance of the trend by making the null hypothesis that the trend, , is not significantly different from 0. From the above discussion of trends in random data with known variance, we know the distribution of trends to be expected from random (trendless) data. If the calculated trend, , is larger than the value, , then the trend is deemed significantly different from zero at significance level .

Noisy time series, and an example

It is harder to see a trend in a noisy time series. For example, if the true series is 0, 1, 2, 3 all plus some independent normally distributed "noise"  of standard deviation , and we have a sample series of length 50, then if  the trend will be obvious; if  the trend will probably be visible; but if  the trend will be buried in the noise.

If we consider a concrete example, the global surface temperature record of the past 140 yéars as presented by the IPCC:  , then the interannual variation is about 0.2 °C and the trend about 0.6 °C over 140 yéars, with 95% confidence limits of 0.2 °C (by coincidence, about the same value as the interannual variation). Hence the trend is statistically different from 0. This alone, however, tells us nothing about the physical causes of the temperature change.

Goodness of fit (R-squared) and trend

The léast-squares fitting process throws out a value - r-squared - which is the square of the residuals of the data after the fit. It says what fraction of the variance of the data is explained by the fitted trend line. Is does not relate to the significance of the trend line - see graph. A noisy series can have a very low r2 value but a very high significance of fit. Often, filtering a series incréases r2 whilst making little difference to the fitted trend or significance.

Real data is auto-correlated

The above discussion assumed the data could be represented as trend + noise, with the noise at éach data point being independent. This is important, as it makes an enormous difference to the éase with which the statistics can be analysed. réal (climate) data rarely fulfills this criterion.

[This section in need of expansion: examples.]

Statistika

Trend estimation


A vortex mixer is small machine used in laboratories to mix small beakers of liquids.

What is inside?
Inside, a vortex mixer has an electric motor which turns a pipe facing upwards. This pipe is attached to a small rubber bowl where one can put a beaker of liquid to be mixed up. The rubber bowl turns quickly and creates a vortex or a spiral flow inside any liquid which is placed on it and is therefore mixed up. Most vortex mixers have controls which let the user control how fast or slow they want the mixer to turn and can also set it to turn continuously for a certain length of time.

Where they are used
Vortex mixers are used in bioscience laboratories to mix two different chemicals for a desired effect or to dilute an acid or an alkali by mixing them with water.

Other websites
 IKA – A vortex mixer manufacturer
 VELP – A vortex mixer manufacturer
  In depth information on the VSM-3 Vortex Mixer
 Talboy – A vortex mixer manufacturer
 In-depth article on vortex mixers
 In-depth article on the structure of a vortex mixer

Laboratory equipment

Vortex mixer


The Civilian Service Medal 1939–1945 is awarded to civilians in Australia during World War II who served in arduous circumstances in support of the war effort as part of organisations with military-like arrangements and conditions of service. The medal was introduced in 1994, following a recommendation of the Committee of Inquiry into Defence and Defence Related Awards.

The Committee intended to extend recognition only to those whose war service in Australia was more arduous than the norm, and was performed under military-like conditions.  Hence, Women's Land Army members, whose work was very physical, required them to live in rural areas away from their homes for lengthy periods, and was subject to military-like discipline, are generally eligible.  On the other hand, members of the industrial workforce involved in munitions production are not eligible, as they overwhelmingly lived at home and were subject to standard civilian working conditions.  The medal is therefore recognition of those not in the armed services, but who experienced wartime working conditions similar to the armed services.

Recipients must have served for at least 180 days in any one or a combination of the 38 eligible groups between 3 September 1939 and 2 September 1945. Recipients of the Civilian Service Medal 1939–1945 do not earn an entitlement to use post-nominal letters. As at 30 June 2006, 6,711 awards of the Civilian Service Medal 1939–1945 had been made.

Description
 The Civilian Service Medal 1939–1945 is bronze and portrays the Southern Cross surrounded by golden wattle, Australia's floral emblem. The Southern Cross represents Australia and the golden wattle represents the civilian population joining in defence of the country.
 The medal ribbon has three vertical bands. The central band is ochre to represent the soil of Australia. The two outer bands are green for the land and food production. The two white stripes on the ribbon represent communication and construction.

References

External links
It's an Honour

Civil awards and decorations of Australia
1994 establishments in Australia
Awards established in 1994

Civilian Service Medal 1939–1945


The Imperial Hotel, Tokyo is a hotel in Tokyo. It was built in the late 1880s at the request of the Japanese aristocracy to increase Western visitors to Japan. It was designed by Frank Lloyd Wright. The hotel site is located just south of the Imperial Palace grounds, next to the previous location of the Palace moat.

The modern hotel overlooks the Palace, the  western-style Hibiya Park, and the Ginza neighborhood. Three buildings have stood on the hotel site, each of which embodied the finest western design of its era. The hotel eventually slipped into decay as time took its toll. In a controversial decision, it was decided to demolish the old hotel and replace it with a high-rise structure, to maximize the use of land.

References

Other websites

Imperial Hotel, Ltd.  (株式会社帝国ホテル; Kabushiki Gaisha Teikoku Hoteru).
Main Entrance Hall and Lobby of Imperial Hotel in the Museum Meiji-Mura
Old Tokyo - Imperial Hotel (Wright)
Legacy of oya stone used in the Imperial Hotel

Frank Lloyd Wright buildings
Buildings and structures in Tokyo
1880s establishments in Japan

Imperial Hotel, Tokyo


Chief Frederick Rotimi Alade Williams, QC, SAN (16 December 1920 – 26 March 2005) was a prominent Nigerian lawyer who was the first Nigerian to become a Senior Advocate of Nigeria. In the 1950s, he was a member of the Action Group and subsequently became the minister for local government and justice. He was the president of the Nigerian Bar Association in 1959, the association is the leading body for lawyers in the country. He left politics in the 1960s, as a result of the political crisis in the Western Region of Nigeria.

Throughout his career, he was involved in some memorable and important court cases, such as Lakanmi vs the Western Government of Nigeria, which set the precedent that a military government could not use its power to make laws that will appropriate an individual's property.  The Oloye Williams, himself a Yoruba chieftain, was also among a group of lawyers that represented the Oba of Lagos, Adeniji Adele, against challenges by the Nigerian National Democratic Party. The latter had previously gained solidarity and foundation from the ruling House of Docemo in Lagos.

Early life

Rotimi Williams was born on 16 December 1920 in Lagos. His older brother was Akintola Williams, born a year earlier, who became a distinguished Chartered Accountant.
His father and uncle were both lawyers, and were called to the bar in 1927 and 1892 respectively. He entered primary school in the 1930s, at the Methodist Ologbowo School, then went to C.M.S Grammar School, Lagos for secondary education. Despite being given a full scholarship to study mechanical engineering at Yaba Higher College, he chose to become a lawyer. He earned his bachelor's degree in 1942 and was called to the bar at the Gray's Inn, London in 1943. He set up the first indigenous Nigerian law firm in 1948 with Chief Remilekun Fani-Kayode and Chief Bode Thomas. The law firm was called "Thomas, Williams and Kayode".

Early political career
In 1943, he became the first Nigerian solicitor to the Supreme Court of Nigeria and soon thereafter entered the political arena as a member of the Nigerian Youth Movement. He rose to become the movement's general secretary. However, the movement was soon embroiled in a crisis which  dented its political support among the Nigerian masses.  When the movement began to fade politically, he was one of the educated members of the Nigerian political class who joined the Action Group. He was the group's legal adviser in the early 1950s. He had previously entered the Western region's House of Chiefs by virtue of his holding of the chieftaincy title of the Apesin of Itoko in Egbaland. He later also served as a member of that region's privy council. He was elected into the Lagos Town Council in 1953 and was subsequently made chairman of the council. In 1957, he became the Western Region's Attorney General, the first Nigerian to be an attorney general. He was made Queen's Counsel in 1958, another first for him, as he was one of the first two Nigerians to be made one.

Constitutional conference
On 18 October 1975, Rotimi Williams became the chairman of the Constitutional Drafting Committee. The body was formed to present a draft constitution to be approved by the military administration of Obasanjo. He led the convention to present an agenda for broad coalition building across ethnic and regional lines. The body pushed for presidential winners to have at least 25% of the total votes cast in two thirds of the nineteen states in Nigeria and that each of the 19 states of the federation should have a minister representing them. The political parties should also have support in at least two thirds of the states.

References

1920 births
2005 deaths
Yoruba legal professionals
Senior Advocates of Nigeria
20th-century King's Counsel
21st-century King's Counsel
Politicians from Lagos
CMS Grammar School, Lagos alumni
20th-century Nigerian politicians
Yoruba politicians
20th-century Nigerian lawyers

Frederick Rotimi Williams


Participants in an online music scene who rearrange spliced parts of musical pieces form mashup culture. The audio-files are normally in MP3 format and spliced with audio-editing software online. The new, edited song is called mashup. The expression mashup culture is also strongly connected to mashup in music. Even though it was not originally a political community, the production of mash-up music is related to the issue of copyright. Mashup Culture is even regarded as "a response to larger technological, institutional, and social contexts".

History
The history of mashup culture in general can be dated back to the beginnings of dada and conceptual art. Artists such as Marcel Duchamp were the first to introduce already existing objects, which they rearranged and combined in collages, to the world of higher art. These artists believed that even though certain artifacts were ascribed a certain meaning, this meaning could be altered through rearranging them and putting them into a new context. However, it was still quite a long way to the beginning of mashup culture in music. From the early 2000s on, music was more and more distributed through the internet. With the introduction of MP3 audio files, it became much easier to access and download music. Not only could music be accessed easier, it could also be transformed and mixed in ways that were not possible before. Especially for younger people, this new gained freedom when it came to the accessibility of audio files lead to the development of a new form of cult around the transformation of musical pieces. This "reworking MP3 recordings pulled from the Internet" was turning into more than just a fashion just as "the Internet is more than just a means of distribution, it becomes a raison d'eˆtre for a culture based on audio data'' states Alistair Riddell in 2001. During that time, the first versions of mashup music were published, sometimes not under the term mashup but under the name of "creative bootleg" or "bastard pop". Even though the creation of a new song by combining at least two samples of different songs was also used in other music styles such as Hip Hop before, it was only with the rise of the MP3 audio file along with easy-to-use computer mash-up programs that mash-up was transformed into an own culture as such. Especially peer-to-peer sharing was contributing to this phenomenon: People who create mashup music can easily distribute it and share it with other people through online programs.

Forms of mashup culture

Mashup culture is motivated by a number of different factors.

Statement of art
Mashup culture is sometimes regarded as a cultural movement against common, existing music that is published by the music industry. In 2002, a Newsweek article described the mashup of songs as a strategy of Londoner DJs to transform music they considered bad into something they could appreciate and were willing to listen to. Even though mashup culture has its origin in online communities, it entered a more art-related realm. It is art used as a statement against the content music industry provides.

Political statement
It can even be considered as a political statement against copyright laws and restrictions imposed by the government as well. "Reframing of the original narrative" is regarded as a way to create a new and unique product which leads to a "fresh perspective" of the original.
Murray states "there's the question of the kind of Internet we want moving forward – one increasingly controlled by corporate gatekeepers who get to sanction what creative expression looks like, or one in which the freedom of this expression is valued above share price". Copyright issues have always been limiting the possibilities of mashup culture. Those implications by law have led to the problem of online piracy. Mashups are often created with illegally acquired content. This closeness to illegality has become part of this culture. "In some cases, the illegality of piracy contributes to the appeal of unauthorized copies online" states Shiga in her article Copy-and-Persist: The Logic of Mash-Up Culture. Even though copyright laws were intentionally supposed to stop illegal downloads, they contributed to the appeal of mashup and to the culture existing around it.

Do-it-yourself culture
Another important aspect of the success of mashup culture nowadays lies in the do-it-yourself or DIY trend. Consumers are turning into producers as well, especially due to the simplification of online tools that help creating personalized content.

Mashup in current literature

DJ Spooky

Paul D. Miller, also known as DJ Spooky, Sound Unbound: Sampling Digital Music and Culture, a book about mashup culture's influence on society. It focuses on "the nature of that transformation", stating that it has been "fuelled by rapid advances in technology that have transformed art and communication". He describes sampling as an essential part of our society. The book was published by the MIT Press and has been regarded highly by scholars such as Lawrence Lessig.

See also
 Mashup (music)
 Mashup (video)
 Mashup (book)
 Mashup (web application hybrid)

Literature

References

Mashup
Intellectual property activism

Mashup (culture)


Events
 January 17 – Gregory XI enters Rome.
 January 27 – The Bad Parliament begins sitting.
 February 23 – The Bad Parliament dissolved.
 May – Continuous riots in Rome induce Gregory XI to remove temporarily to Anagui.
 May 22 – Gregory XI issues five Bulls in which the opinions of John Wyclif are condemned.
 June 21 – Edward III dies at age 65.
 July 16 – Coronation of 10-year-old Richard II.
 October 13 – Richard II's first parliament meets.
 October 18 – Andronicus IV Palaeologus crowned emperor in Constantinople.
 Informed that khan Urus of the White Horde has died, Timur Lenk sends Tokhtamish to take the Horde throne, but the successor of Urus defeats him.
 Mamluk sultan Sha'ban II is succeeded by 'Ali II.
 Muhammad al-Mutawakkil I is briefly deposed this year as Abbasid puppet caliph of the Mamluks, Zakariyya' al-Mu'tasim taking the throne for that period.
 A sermon by a German monk states "the game of cards has come to us this year" and prohibitions against cards are issued by John of Castile and the cities of Florence and Basel.
 Papal legate to northern Italy Robert of Geneva (the future Clement VII) pillages Cesena and 4,000 antipapal rebels are massacred.

1377


Chromium(III) sulfate is a chemical compound. Its chemical formula is Cr2(SO4)3. It is a colored compound. It is made by dissolving chromium or chromium(III) oxide in sulfuric acid. It can also be made by reduction of chromates by sulfur dioxide. It turns green when heated. It is used to make leather. Chrome alum was used in the past. It's an irritant.

Related pages
Chromium(III) chloride
Dichromate
Chromium

Sulfur compounds
Chromium compounds

Chromium(III) sulfate


The Hollow-Face illusion (also known as Hollow-Mask illusion) is an optical illusion in which the perception of a concave mask of a face appears as a normal convex face.

While a convex face will appear to look in a single direction, and the gaze of a flat face, such as the Lord Kitchener Wants You poster, can appear to track a moving viewer, a hollow face can appear to move its eyes faster than the viewer: looking forward when the viewer is directly ahead, but looking at an extreme angle when the viewer is only at a moderate angle.

According to Richard Gregory, "The strong visual bias of favouring seeing a hollow mask as a normal convex face is evidence for the power of top-down knowledge for vision". This bias of seeing faces as convex is so strong it counters competing monocular depth cues, such as shading and shadows, and also very considerable unambiguous information from the two eyes signalling stereoscopically that the object is hollow. The illusion can be reinforced even more if a concave face is lit from below, as this will reverse the shading cues, making them closer to those of a convex face lit from above.

The Hollow-Face illusion has been used to study the dissociation between vision-for-perception and vision-for-action (see Two-streams hypothesis). In this experiment, people used their finger to make a quick flicking movement at a small target attached to the inside surface of the hollow – but apparently normal – face, or on the surface of a normal protruding face. The idea was that the fast flicking (rather like flicking a small insect off the face) would engage the vision-for-action networks in the dorsal stream – and thus would be directed to the actual rather than the perceived position of the target. The results were clear. Despite the presence of a robust illusion in which people perceived the hollow face as if it were a normal protruding face, the flicking movements they made were accurately directed to the real, not the illusory location of the target. This result suggests that the bottom-up cues that drive the flicking response are distinct from the top-down cues that drive the Hollow-Face illusion.

Another example of the Hollow-Face illusion is the "Gathering 4 Gardner" dragon. This dragon's head seems to follow the viewer's eyes everywhere (even up or down), when lighting, perspective and/or stereoscopic cues are not strong enough to tell its face is actually hollow. Keen observers will note that the head doesn't actually follow them, but appears to turn twice as fast around its center than they do themselves.

The Hollow-Face illusion is weaker among people with schizophrenia and other populations with psychotic symptoms, perhaps as a result of reduced tendency to interpret any kind of ambiguous 3D object as convex. It appears to be related to current mental state, namely in regard to current positive symptoms, inappropriate affect, and need for structure. The illusion seems to strengthen among successfully treated patients.

People on the autism spectrum have been shown to be less susceptible to visual illusions, including the hollow-face illusion.

Examples

See also
Illusion

References

External links
"The Hollow Face Illusion" at Grand Illusions

Optical illusions

Hollow-Face illusion


Encyclopaedia Metallum: The Metal Archives (commonly kent as Metal Archives per the URL or juist MA) is a wabsteid whilk leets baunds frae various forms o hivy metal. Encyclopaedia Metallum wis described bi Matt Sullivan o Nashville Scene as "the Internet's central database for aw that is 'tr00' in the metal warld." Terrorizer described the site as, "a fou-exhaustive leet o pretty muckle ivery metal baund iver, wi fou discographies, an active forum an an interlinkin members leet that shaws the iver-incestuous beauty o the metal scene". Still an on, there is exceptions for baunds whilk faw unner disputit genres no acceppit bi the wabsteid.

Encyclopaedia Metallum ettles tae provide comprehensive information on lika baund, lik a discography, logos, pictures, leerics, line-ups, biography, trivia an uiser-submittit reviews. The steid provides a seestem for submittin baunds tae the archives an aw.

Uiser interaction
As an incentive fur tae get fowk tae submit data, the steid uises a "point" seestem, in whilk registered uisers gain pynts an muive up ranks wi the amoont an value o data an information they submit. When joinin as a member o the steid aw new members start aff wi the rankin o "mallcore kid". The mair valuable an complete the information, the mair points ar awairdit. An aa submittin reviews o baund releases is anither way tae gain points on the steid. Typically though, the wabsteid affers mair points tae those who submit info aboot a baund itself. The maist points are gien tae uisers when actual baunds they submit tae the site are acceptit.

The wabsteid is notably completely free o advertisements, an as o 2012 is run completely independently. Some, housomeivver, quaisten whether or no this affects the quality o the wabsteid. Syne the mids o 2005, frequent veesitors noticit that the steid wis aften doun, though the stability situation began tae impruive in the beginnin o 2006. Through the first three month o 2007 the steid ran relatively free o dountime, wi the exception o late Mairch. The steid went doun unexpectedly for five days at the end o December an aw. This wis in pairt due tae an issue wi the company that hostit the steid. When the company chyngit its business strategy, Metal Archives wis left oot o the process an wis subsequently ignored. The issue haes syne been correctit an the steid is runnin normally again.

Acceptit baunds
The steid is kent for its extremely strict rules, especially those which mandate baund submissions. Encyclopaedia Metallum anerlie accepts baunds which it deems metal, but mony baunds that ance wur rejectit wur acceptit later on, an vice versa. The anerlie exceptions are: side projects o members o metal baunds that hae a release on a label wi warldwide distribution, baunds that are nae langer considered tae be metal but wur in the past, an grindcore baunds that bear close similarities tae daith metal.

Traditional hivy metal genres an eras, such as the NWOBHM hae stringent rulings; uisers ar warned in the rules section tae consider baunds submittit unner these classifications as "ambiguous", in the sense that if a baund is submittit wi these terms as their genre, the muisic will be extensively reviewed bi the moderators afore they decide whether or no tae accept the baund ontae the wabsteid. This is acause in the past, some submissions labeled wi those genres hae turned oot no tae be metal, accordin tae the steid's guidelines. Some baunds which are commonly referred tae as traditional hivy metal an NWOBHM, such as Def Leppard an Stryper, ar on the wabsteid due to anerlie ane or twa o the baunds' albums meetin the wabsteid's specifications.

Additionally, there are some nan-metal baunds featured on the steid that are considered tae be pairt o the metal scene despite no being metal thairsels (uisually daurk ambient an fowk baunds, examples being Mortiis, Elend, Nest, :Of The Wand & The Moon:, Autumn Tears, Stille Volk, etc). These baunds ar selectit bi the moderators "in an admittedly arbitrary fashion," an their submission bi normal uisers is discouragit.

Baunds excludit bi the wabsteid
Genres that are sometimes associatit wi extreme metal, such as grindcore an metalcore, are absent as they ar seen tae hae mair in common wi punk than metal an aw. Some grindcore baunds are acceptit if they are mair associatit wi daith metal (e.g. Napalm Death, an Pig Destroyer). Mony uisers believe that metalcore baunds hae been completely banned frae the wabsteid syne a bulletin wis postit that simply statit, "Please stop submittin -core baunds. Please." Housomeivver, this is false; mony metalcore baunds appear on the archives an mony mair hae been addiy syne the bulletin wis postit, but the moderators hae become mair strict on wha metalcore baunds can be addit an generally wirk case-bi-case rather than sayin aw, or zero, metalcore baunds will be acceptit. Maist o the metalcore baunds that are allouit are the anes hivily influenced bi melodic daith metal. Glam metal is rejectit if the websteid awners consider the baund mair hard rock than metal. Industrial metal is anerlie allouit if the site's staff consider it "mair metal relatit than industrial", for example; the baund Rammstein is no alloued, while industrial rock pioneers Ministry wur finally acceptit in Mairch 2006 (based on the newer ootput o this baund which haes incorporatit a lot o thrash metal influence). Anither recent acceptit baund ance blocked bi the administration is the industrial group Pitchshifter, based on their first three metal-influencit albums. Encyclopaedia Metallum can anerlie accept grunge an alternative metal baunds if awners consider them "metal"; The Melvins, Soundgarden, Helmet, Faith No More an Alice in Chains hae aw been acceptit, while Nirvana, Pearl Jam, Tool an Chevelle are no allouit on the steid.

Baunds that are associatit wi the nu metal label are completely forbidden an hae been syne the wabsteid stairtit. Housomeivver, certain baunds which are commonly regardit as nu metal wur acceptit an aw, if the moderators considered certain albums "metal" enough. This pairticular loophole wis exploitit tae comedic effect on Aprile Fools' Day 2009 bi the steid's staff when popular nu metal baund Korn wis briefly addit tae the database, whareupon a series o stagit arguments atween moderators appeared throughoot the day on the steid's forum.

The steid runners hae standards which exclude some baunds that are considered bi some sites (such as Allmusic or juist mention Led Zeppelin as "hard rock".

In fact, mony o what are aften viewed as the oreeginal 1970s hivy metal baunds are missin frae the wabsteid, such as Blue Öyster Cult, Uriah Heep, Vanilla Fudge, Cactus an Dust. A sma amoont o uisers hae questioned these exclusions on the wabsteid's message buird in the past. In the ither hand, ither 1970s baunds such as Black Sabbath, Deep Purple, Scorpions, Sir Lord Baltimore, Rush, Rainbow, Thin Lizzy, Budgie an Pentagram ar acceptit.

References

Fremmit airtins
 Encyclopaedia Metallum: The Metal Archives
 Translatit interview frae Miasma Magazine
 Translatit interview frae Arsenic Magazine
 Airticle aboot Encyclopaedia Metallum in Examiner.com

Hivy metal

Encyclopaedia Metallum


Aitne or , is a non-spherical moon of Jupiter. It was found by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2001, and given the designation .

Aitne is about 3 kilometres in diameter, and orbits Jupiter at an average distance of 22,285,000 km in 679.641 days, at an inclination of 166° to the ecliptic (164° to Jupiter's equator), with an orbital eccentricity of 0.393.

It was named in August 2003 after Aitna or Aitne, the divine personification of Mount Etna, whose sons by Zeus (Jupiter) are the Palici, the twin sicilian gods of geysers (other authors have them descend from Thalia and/or Hephaistos).

Aitne belongs to the Carme group, made up of non-spherical irregular retrograde moons orbiting Jupiter at a distance ranging between 23,000,000 and 24,000,000 km and at an inclination of about 165°.

References

Jupiter's moons

Aitne (moon)


Hostage Working Group was organized by the U.S. Department of State at the US Embassy in Baghdad in the summer of 2004 to monitor hostages in Iraq. Reported as meeting "weekly to bring together officials from the FBI, the Defense Department, the State Department and the Iraqi government. Officials do not publicly discuss the actions they can take against kidnappers."1

In an interview in the magazine, Talk Through, of the UK's Ministry of Defence Police, April/May 2005, PC Peter Anderson, who was working with the Hostage Working Group (HWG) describes himself as: "the only non-American in this 30-strong group."

Erik Rye was identified as the director of the Hostage Working Group at the US Embassy in Baghdad in an editorial 3 in the International Herald Tribune on May 17, 2006.

A statement issued September 7, 2006 by the White House 4 identified another group working out of the US Embassy in Baghdad, the Office of Hostage Affairs. It is unknown if this is a new group or an alternative name for the Hostage Working Group.

External links
 Hostages of War International Herald Tribune, May 17, 2006
Fast Chat: 'She Came Home Alive' Newsweek, April 10, 2006
Job Description for the Coordinator of the Hostage Working Group USAJobs.org, June 22, 2005
Talk Through (PDF) The Magazine of the UK's Ministry of Defence Police, Living the Baghdad experience, May/April, 2005
U.S. Hostages Kept Low Profile In Ritzy Baghdad Neighborhood Larry Kaplow, Cox News Service, September 9, 2004
Victim's Tale... International Herald Tribune, May 7, 2006
State Department Briefing March 7, 2006
Some Grounds for Optimism over Wood Australian Broadcasting Corporation March 5, 2005
The Missing Newsweek, March 13, 2006

Iraq War
Iraqi insurgency (2003–2011)

Hostage taking

Hostage Working Group


Disibodenberg () is a monastery ruin near Staudernheim in Rhineland-Palatinate, Germany. It was founded by Saint Disibod. Hildegard of Bingen, who wrote Disibod's biography "Vita Sancti Disibodi", lived in Disibodenberg for 39 years.

In 640, Disibod came as a missionary from Ireland to Francia. After working for 10 years in Vosges and Ardennes, he arrived near Odernheim am Glan and started teaching there. After his death, the monastery was founded. The Normans and the Hungarians plundered and destroyed the site several times, but Archbishop Willigis of Mainz rebuilt the church and monastery in the 10th century. It was home to famed saint Hildegard Von Bingen throughout much of the 12th century.

Notes
 Wolfgang Müller: Nahekunde: Sobernheim und seine Umgebung im Wechsel der Zeiten. Sobernheim a. d. Nahe: H. Schäffling, 1924.
 Charlotte Kerner: Alle Schönheit des Himmels - Die Lebensgeschichte der Hildegard von Bingen. 1993
 Eberhard J. Nikitsch: Kloster Disibodenberg. Religiosität, Kunst und Kultur im mittleren Naheland. (Große Kunstführer Bd. 202). Regensburg 1998.

External links

 Scivias-Stiftung Disibodenberg

Monasteries in Rhineland-Palatinate
Naheland

Church ruins in Germany
Ruined abbeys and monasteries

Disibodenberg


Patriarch Dymytriy (Yarema) (9 December 1915 – 25 February 2000) was the second patriarch of Kyiv and all Ukraine, and of the Ukrainian Autocephalous Orthodox Church (UAOC). Patriarch Dymytriy (Yarema) was successor to Patriarch Mstyslav (Skrypnyk) from 1993 to 2000 and was succeeded by Metropolitan Mefodiy (Kudryakov).

Biography
He was a renaissance man who had studied art and music in his younger years, a leader with a developed political conscious who was a member of the Organization of Ukrainian Nationalists in the 1930s.

During World War II he was a prisoner of war in Germany.
He was ordained to the diaconate on August 3, 1947, and to the priesthood on August 10 of that same year. In 1947–89 he was a member of the clergy of the Moscow Patriarchate.
In 1989 he and the other members of the clergy left the Moscow Patriarchate and declared to be put under the omophor of the Ukrainian Autocephalous Orthodox Church under Metropolitan Mstyslav (Skrypnyk) who was at that time the head of the Ukrainian Autocephalous Orthodox Church in USA and Canada.

By 1990, with the Soviet Union falling apart, The Right Rev Fr. Dymitry Yarema initiated and was a participant in the first All-Ukrainian Sobor of the UAOC, held in Kyiv in 1990, which elected Metropolitan Mstyslav as the first patriarch of Ukraine.

In 1993 he took his monastic vows and then was ordained bishop of Pereyaslav and Sicheslav by Archbishop of Lviv Petro (Petrus). At the 2nd Council of the Church in 1993 he was voted Patriarch of Kyiv and all Rus'-Ukraine.

In late 1998 the aging Patriarch Dymytriy, his health weakening, determined that the future of the Church would be strengthen if it would turn once again to the Ukrainian diaspora, which had maintained the UAOC during nearly 70 years of Communist rule in Ukraine.

The choice Patriarch Dymytriy made in his last will and testament to request that the UAOC hierarchy agree to allow Metropolitan Constantine of the Ukrainian Orthodox Church of the USA to guide it – which, if carried out, would effectively unite the two Churches – was a calculated move to save the UAOC from further incursions from the larger Ukrainian Orthodox Church - Kyiv Patriarchate, and the Ukrainian Orthodox Church (Moscow Patriarchate).

References
Religious Information Service of Ukraine

Primates of the Ukrainian Autocephalous Orthodox Church
1915 births
2000 deaths
People from Brzozów County
Clergy from the Kingdom of Galicia and Lodomeria
Ukrainian Austro-Hungarians
Ukrainian art historians
Polish military personnel of World War II
World War II prisoners of war held by Germany
20th-century  Ukrainian historians
Organization of Ukrainian Nationalists members

Demetrius (Yarema)


A chromophore is the part of a molecule responsible for its colour.

The colour is caused when a molecule absorbs certain wavelengths of visible light. It transmits or reflects only other wavelengths, which causes the colour we see.

In biological molecules that capture or detect light energy, the chromophore is the part of the molecule which responds when hit by light.

Chromophores make the colour in chromatophores, which are the pigment-containing and light-reflecting cells found in many animals.

References

Chemical compounds

Chromophore


Communism is a far-left political system that wants a world without different social class groups. Communists believe these differences are a kind of oppression. They say that things like factories, tools and farms (the means of production) are owned by only some people (the bourgeoisie) which gives them unfair power over other people. Communists want these things to be owned by the workers instead of the bosses. They believe this will bring about the end of all money and private property.

This is the opposite to capitalism where there is money, a state and class structure. In capitalism, there is a working class (people who don't own the means of production, also called the proletariat) and the owning class (people who own the means of production, sometimes called the ruling class or the bourgeoisie).

Communist thinkers believe a communist world can happen if the working class take away the power of the bourgeoisie and start to control the means of production.

Countries that officially follow forms of communism include Vietnam, China, Cuba and Laos, which are Marxist–Leninist, and North Korea, which follows Juche.

The most famous communist thinkers were Karl Marx and Friedrich Engels; other prominent thinkers include Vladimir Lenin, Joseph Stalin, Leon Trotsky, and Mao Zedong.

History

In 1848, Karl H. Marx and Friedrich Engels wrote The Communist Manifesto. It was a short book with the basic ideas of communism. Most socialists and communists today still use this book to help them understand politics and economics. Many non-communists read it too, even if they do not agree with everything in it.

Karl Marx said that for society to change into a communist way of living, there would have to be a period of change. During this period, the workers would govern society. This is called a dictatorship of the proletariat. Marx was very interested in the Paris Commune of 1870, when the workers of Paris ran the city after the Prussian Army defeated the French Army. He thought that this practical experience was more important than the theoretical views of the various radical groups.

Many groups and individuals liked Marx's ideas. By the beginning of the twentieth century, there was a worldwide socialist movement called Social Democracy. It was influenced by his ideas. They said that the workers in different countries had more in common with each other than the workers had in common with the bosses within their own countries. In 1917, Vladimir Lenin and Leon Trotsky led a Russian group called the Bolsheviks in the October Revolution. They got rid of the temporary government of Russia, which was formed after the February Revolution against the Tsar (Emperor). They established the Union of Soviet Socialist Republics, also called the Soviet Union or USSR.

The Soviet Union was the first country claiming to have established a workers' state. In reality, the country never became communist in the way that Marx and Engels described.

During the 20th century, many people tried to establish workers' states. In the late 1940s, China also had a revolution and created a new government with Mao Zedong as its leader. In 1959, the island of Cuba had a revolution and created a new government with Fidel Castro as its leader. At one time, there were many such countries, and it seemed as though communism would overtake capitalism. However, communist party governments didn't use democracy. Because of this, the governments became separated from the people, making communism difficult. This also led to disagreements and splits between countries.

By the 1960s, one third of the world had overthrown capitalism and were trying to build communism. Most of these countries followed the model of the Soviet Union. Some followed the model of China. The other two thirds of the world still lived in capitalism, and this led to a worldwide divide between capitalist countries and communist countries. This was called the "Cold War" because it was not fought with weapons or armies, but competing ideas. However, this could have turned into a large war. During the 1980s, the United States and the Soviet Union were competing to have the biggest army and having the most dangerous weapons. This was called the "Arms Race". President Ronald Reagan called communist countries like the Soviet Union the "Evil Empire" because he did not agree with communist ideas.

Since 1989, when the Berlin Wall was torn down, most countries that used to be communist have returned to capitalism. Communism now has much less influence around the world. In 1991, the Soviet Union broke up. However, around a fifth of the world's people still live in states controlled by a communist party. Most of these people are in China. The other countries include Cuba, Vietnam, Laos, and North Korea. There are also communist movements in Latin America and South Africa.

Disputes
Many people have written their own ideas about communism. Vladimir Lenin of Russia thought that there had to be a group of hard-working revolutionaries (called a vanguard) to lead a socialist revolution worldwide and create a communist society everywhere. Leon Trotsky, also from Russia, argued that socialism had to be international, and it was not important to make it happen first in Russia. He also did not like Joseph Stalin, who became the leader of the USSR after Lenin's death in 1924. Trotsky was made to leave the Soviet Union by Stalin in 1928, and then killed in 1940. This scared many people, and lots of communists argued about whether this was right and whose ideas should be followed.

Mao Zedong of China thought that other classes would be important to the revolution in China and other developing countries because the working classes in these countries were small. Mao's ideas on communism are usually called Maoism or Mao Zedong Thought. After Stalin's death in 1953, Mao saw himself as the leader of worldwide communism until he died in 1976. Today the Chinese government is still ruled by the Communist Party, but they actually have what is called a mixed economy. They have borrowed many things from capitalism. The government in China today does not follow Maoism. However, few revolutionaries in other countries like India and Nepal still like his ideas and are trying to use them in their own countries.

Term usage
The word "communism" is not a very specific description of left-wing political organizations. Many political parties calling themselves "communist" may actually be more reformist (supportive of reforms and slow change instead of revolution) than some parties calling themselves "socialists". Many communist parties in Latin America have lost many members because these parties do different things than what they promised once they get into power. In Chile, between 1970 and 1973, under the left-wing Coalition (groups of parties) of Popular Unity, led by Salvador Allende, the Communist Party of Chile was to the right of the Socialist Party of Chile.  This means it was more reformist than the socialist party.

Many communist parties will use a reformist strategy. They say working-class people are not organized enough to make big changes to their societies. They put forward candidates that will be elected democratically. Once communists become elected to parliament or the Senate, then they will fight for the working class. This will allow working-class people to change their capitalist society into a socialist one.

Symbols and culture

The color red is a symbol of communism around the world. A red five-pointed star sometimes also stands for communism. The hammer and sickle is a well-known symbol of communism. It was on the flags of many communist countries, like the Soviet Union (see top of article). Some communists also like to use pictures of famous communists from history, such as Marx, Lenin, and Mao Zedong, as symbols of the whole philosophy of communism.

A song called The Internationale is the international song of communism. It has the same music everywhere, but the words to the song are translated into many languages. The Russian version was the national anthem of the Soviet Union from 1922 until 1944.

The sickle in the Soviet Union's flag shows the struggle of the peasants-farmers. The hammer in the flag represents the struggle for the workers. Both of them crossing shows their support for each other.

There is also a special kind of art and architecture found in many communist and former communist countries. Paintings done in the style of socialist realism are often done for propaganda to show a perfect version of a country's people and political leader. Art done in the socialist realism style, such as plays, movies, novels, and paintings show hard-working, happy, and well-fed factory workers and farmers. Movies, plays and novels in this style often tell stories about workers or soldiers who sacrifice themselves for the good of their country. Paintings often showed heroic portraits of the leader, or landscapes showing huge fields of wheat. Stalinist architecture was supposed to represent the power and glory of the state and its political leader. Some non-communists also enjoy this kind of art.

Related pages
 Socialism
 Anti-capitalism
 Stalinism
 Karl Marx
 Marxism
 Trotskyism
 Capitalism
 Leninism

References

Other websites

Communism