Generators info

The Schreier-Sims algorithm is an efficient method of computing a base and strong generating set (BSGS) of a permutation group. In particular, an SGS determines the order of a group and makes it easy to test membership in the group. Since the SGS is critical for many algorithms in computational group theory, computer algebra systems typically rely on the Schreier-Sims algorithm for efficient calculations in groups.

The running time of Schreier-Sims varies on the implementation. Let <math> G \leq S_n </math> be given by <math>t</math> generators. For the deterministic version of the algorithm, possible running times are:

• <math>O(n^2 \log^3 |G| + tn \log |G|) </math> requiring memory <math>O(n^2 \log |G| + tn)</math>
• <math>O(n^3 \log^3 |G| + tn^2 \log |G|) </math> requiring memory <math>O(n \log^2 |G| + tn) </math>

The use of Schreier vectors can have a significant influence on the performance of implementations of the Schreier-Sims algorithm.

For Monte Carlo variations of the Schreier-Sims algorithm, we have the following estimated complexity:

<math>O(n \log n \log^4 |G| + tn \log |G|)</math> requiring memory <math>O(n \log |G| + tn)</math>

In computer algebra systems, an optimized Monte Carlo algorithm is typically used.

See also Schreier’s subgroup lemma.

References

• Seress, A. Permutation Group Algorithms. Cambridge U Press, 2002.

A world clock is a clock which displays time from around the world. The clock face can be multiple round analog clocks with moving hands or digital clocks with numeric readouts. Each clock is labeled with the name of a major city or time zone in the world. It could also be a picture map of the world with light projection representing daytime.

External Links

• World Clock requires Flash and displays world demographic estimates
• World Clock Information displays the date and time for over 250 cities on a world map
• The World Clock - Time Zones, Current local times around the world. Includes Personal World Clock - shows just the cities you need.
• gChart World Running Clock on Google Map - Current local times around the world in real-time running clock by a single click on Google world map.
• World Clock - Current Local Times continously updating times for major world cities

Personal shopping is a occupation of people who help others shop by giving advice and making suggestions to customers. They are often employed by department stores and boutiques (although some are freelance or work exclusively online). Their focus is usually on clothes, although the number of non-clothing stores - such as furniture retailers - that offer personal shopping services is on the rise, and many freelance personal shoppers will help customers shop in whatever item they happen to be after.

A personal shopper will give the customer focused and individual attention, and will advise the customer of what is in fashion, help the customer to decide what looks good on them, or assist in picking out an outfit for a particular occasion- or even an entire wardrobe for a particular season. They will often also conduct other services such as a colour analysis, enabling the customer to better understand which colours suit them best, or which colours should be worn for which seasons.

A personal shopper is typically employed by the store itself, which means that payment for the service is not required - only the items bought. Other stores will charge a small fee to use their personal shoppers.

Online personal shopping

An online personal shopper’s job is to spend time online searching on behalf of clients. Their focus is usually on anything that the web can provide. An online personal shopper is typically freelance however some are employed by impartial websites that offer online shopping advice. Online personal shopping services typically begin with a request or question from the client about the item, product or service that they are looking for. Customers are typically required to pay for the information. After the online personal shopper has located the item or items according to the client’s needs, the customer is notified.

External link

• Personal Shoppers Online
• Personal Shopper and Errand Service

The Holtzman Inkblot Test, conceived by Wayne Holtzman, is a personality test similar to the Rorschach inkblot test. The Holtzman Inkblot Test was invented to correct many — if not all — of the controversial issues aroused by the Rorschach Inkblot Test.

The test consists of two alternate forms of forty-five inkblots. Scoring is based on twenty-two items: reaction time, rejection, location, space, form definiteness, form appropriateness, color, shading, movement, pathognomonic verbalization, integration, content (human, animal, anatomy, sexual, or abstract), anxiety, hostility, barrier, penetration, balance, and popularity.

Scoring takes a very long time if the test is not done on a computer. The Holtzman Inkblot Test is used primarily on students, children, people with schizophrenia or head injuries and depressed patients. Professionals are necessary in order to obtain accurate results in such a test. Recommended uses of the Holtzman Inkblot Test are experimental and clinical applications.

External links

• CPS Website

Sparse binary polynomial hashing (SBPH) is a generalization of Bayesian filtering that can match mutating phrases as well as single words. SBPH is a way of generating a large number of features from an incoming text automatically, and then using statistics to determine the weights for each of those features in terms of their predictive values for spam/nonspam evaluation.

External links

• A paper on the subject as it relates to spam (some article text comes from this document, which is under the GFDL)

The tranquility principle of the Bell-LaPadula model states that the classification of a subject or object does not change while it is being referenced.

There are two forms to the tranquility principle:

1) The “principle of strong tranquility” states that security levels do not change during the lifetime of the system

2) The “principle of weak tranquility” states that security levels do not change in a way that violates the rules of a given security policy.

The G₀ phase (G sub 0) is a period in the cell cycle where cells exist in a quiescent state. Cells enter the G₀ phase from a cell cycle checkpoint in the G₁ phase, such as the restriction point (animal cells) or the start point (yeast). This usually occurs in response to a lack of growth factors or nutrients. During the G₀ phase, the cell cycle machinery is dismantled and cyclins and cyclin-dependent kinases disappear. Some cells remain in the G₀ phase until there is a reason for them to divide.

Although many cells in the G₀ phase may die along with the organism, this does not mean that cells that enter the G₀ phase are destined to die; this is simply a consequence of the cell lacking any stimulation to re-enter in the cell cycle.

See also

• Cell Cycle
• G1 phase
• S phase
• G2 phase
• M phase
• prophase
• prometaphase
• chromosome
• prokaryote
• anaphase
• telophase

WinImage is a disk imaging application for Microsoft Windows. It was originally created by Gilles Vollant Software.

Using WinImage one can:

• Create an exact copy of a physical disk such as a floppy, CD-ROM or Hard disk
• Write disk images back on to physical media
• Insert files in to a disk image
• Extract files from a disk image
• Create blank images
• Change an image format
• Defragment a disk image
• Create self-extracting disk images

External links

• Official Website

In mathematics, a symmetric function of multiple variables is one that is invariant under permutation of its variables; that is, the value of the function does not depend on the order of the n-tuple of arguments.

In most contexts, the term refers to a polynomial with this property: a symmetric polynomial.
The theory of symmetric polynomials is part of the theory of polynomial equations, and also a substantial chapter of combinatorics. Examples of symmetric polynomials are

X₁ + X₂ + … + X_n ,

X₁³ + X₂³ + … + X_n³ ,

and

X₁X₂…X_n .

If P(x) is a polynomial with roots

α₁, α₂, …, α_n ,

a symmetric function of the roots of P means

S(α₁, α₂, …, α_n)

where S is a symmetric function of n variables.

There is a direct relation between certain symmetric functions of the roots and the coefficients in the polynomial P. Assume for simplicity that P is monic, so that

P(x) = xⁿ + a_n−1xⁿ⁻¹ + … + a₀ = (x − α₁)(x − α₂)…(x − α_n),

where the a_i are in a field K and the α_i are in the algebraic closure of K. The sum of all the α_i equals −a_n−1 and their product equals (−1)ⁿa₀. In fact, it is classical algebra (Viète’s formulas) that the intermediate coefficients of P are plus or minus the sums of the products of the roots taken j at a time, for 1 < j < n. (The sign is alternately + and −.) These formulae are the basis of the traditional theory of equations. In symbols the formulas say:

a_n−j = (−1)^n−j Σ α_k(1)…α_k(j)

with the summation taken over all index sequences

1 ≤ k(1) < … < k(j) ≤ n.

These sums for j = 1, 2, …, n are called the elementary symmetric functions of the roots, because the jth elementary symmetric polynomial, written σ_j, is given by the same formula, but in indeterminates X_i. A basic theorem states that any symmetric polynomial function S of n variables can be expressed as a polynomial in the elementary symmetric functions. In the solution of polynomial equations, the symmetric polynomials of the roots lie in K.

The polynomial relations underlying that assertion are universal (independent of choice of P); and, if we work with the symmetric polynomials created from a monomial, we can eliminate dependence on K, too, to get formulae with integer coefficients. Putting this more algebraically, we can define a subring Symm(n) of Z[X₁, X₂, …, X_n] consisting of the integral symmetric polynomials (those invariant under the action of the symmetric group on indices); and then assert that the formulae for σ_j, for which we retain the notation, are ring generators of Symm(n). What is more, they are independent generators (no algebraic relations hold), so that Symm(n) is abstractly also a polynomial ring on n generators. A great deal of attention was paid, in older algebra textbooks, to algorithmic procedures expressing the procedural content of this (which has been stated as an existence theorem but has computational content).

The most important single application is to the power sums α₁^k + α₂^k + … + α_n^k, in terms of the a_j. The formulae for doing this are attributed to Isaac Newton. They were encountered in K-theory too, where they underlie the Adams operations.

They also support the theory of the Newton polygon, part of the theory of ramification. In Newton’s case the point was to work with a_j in a formal power series ring; here passage to the algebraic closure is the theory of Puiseux expansions in fractional powers, and the Newton polygon is a device for computing the required exponents.

See also

• Newton’s identities
• Symmetric matrix

A panmagic square, pandiagonal magic square, diabolic square, diabolical square or diabolical magic square is a magic square with the additional property that the broken diagonals, i.e. the diagonals that wrap round at the edges of the square, also add up to the magic constant.

A panmagic square remains a panmagic square not only under rotation or reflection, but also if a row or column is moved from one side of the square to the opposite side. As such, an n×n panmagic square can be regarded as having <math>8n^2</math> orientations.

4×4 panmagic squares

The smallest non-trivial panmagic squares are 4×4 squares.

In 4×4 panmagic squares, the magic constant of 34 can be seen in a number of patterns in addition to the rows, columns and diagonals:

• Any of the sixteen 2×2 squares, including those that wrap around the edges of the whole square, e.g. 14+11+4+5, 1+12+15+6
• The corners of any 3×3 square, e.g. 8+12+5+9
• Any pair of horizontally or vertically adjacent numbers, together with the corresponding pair displaced by a (2, 2) vector, e.g. 1+8+16+9

Thus of the 86 possible sums adding to 34, 52 of them form regular patterns, compared with 10 for an ordinary 4×4 magic square.

There are only three distinct 4×4 panmagic squares, namely the one above and the following:

In any 4×4 magic square, any two numbers at the opposite corners of a 3×3 square add up to 17. Consequently, no 4×4 panmagic squares are associative.

5×5 panmagic squares

There are many 5×5 panmagic squares. Unlike 4×4 panmagic squares, these can be associative. The following is a 5×5 associative panmagic square:

4×4 magic square with arbitrary sum

M=35.

Notice the spot of 13 is incremented to 14 in order to obtain the needed sum. We can get 36 by incrementing at 9, and 37 by incrementing at 5.

This symmetric magic square is known with in Mathematics department prior to 1980 at Sainik School, Amaravathinagar. Origin unknown though. See also date magic square.

Open Kinetic Chain Exercises (OKCE) These exercises are performed typically where the hand or foot is free to move. These exercises are typically non-weight bearing, with the movement occurring at the elbow or knee joint. If there is any weight applied it is applied to the distal portion of the limb.
The opposite of OKCE are Closed kinetic chain exercises.

Arm exercises

Bench press

Leg exercises

Knee extensions and straight leg raises. OKCE for legs concentrates on a strong quadriceps contraction, which will strengthen the quadriceps and restore quadriceps power output.

In the occipital bone, at the point of intersection of the four divisions of the cruciate eminence is the internal occipital protuberance.

See also

• external occipital protuberance

External links

• Diagram at uni-mainz.de

The Latvian Gambit is an aggressive but dubious chess opening, which often leads to wild complications. This opening is virtually never seen at the top levels, but some correspondence chess players are devoted to it.

It was formerly known as the Greco Counter Gambit until the new name was made official by the FIDE Congress of 1937. The new name was a tribute to the Latvian players, notably Karlis Betins, who analyzed it in the early part of the 20th century. The original name commemorated the Italian player Gioachino Greco (1600-1634).
The opening is characterized by the following moves which give it the appearance of a King’s Gambit with the colours reversed.

1.e4 e5

2.Nf3 f5?!

At this point several possible moves by White have been studied, of which the most important are

• 3.Nxe5 - the main line. Now after the usual 3…Qf6 (3…Nc6?! is also known), White chooses between 4.d4 d6 5.Nc4 fxe4 and the immediate 4.Nc4, which has the advantage of allowing White to open the center with d3, for example 4…fxe4 5.Nc3 Qg6?! 6.d3 exd3? 7.Bxd3 Qxg2? and now White is winning after 8.Qh5+ Kd8 (or 8…g6 9.Qe5+ and 10.Be4) 9.Be4 Qg6 10.Qxg6 hxg6 11.Bxg6.
• 3.Bc4 This may lead to perhaps the most notorious and heavily analyzed line of the Latvian, which begins 3…fxe4 4.Nxe5 Qg5 (4…d5 5. Qh5+ g6 6.Nxg6 Nf6 7. Qh4 is slightly less insane) 5.d4 Qxg2 6.Qh5+ g6 7.Bf7+ Kd8 8.Bxg6! Qxh1+ 9.Ke2 Qxc1 (9…c6 is a major alternative) 10.Nf7+ Ke8 11.Nxh8+ hxg6 12.Qxg6+ Kd8 13.Nf7+ Ke7 14.Nc3!.
• 3.Nc3 American grandmaster Joel Benjamin has claimed that this sensible developing move refutes the Latvian.
• 3.exf5
• 3.d4

The ECO code for the Latvian Gambit is C40 (King’s knight Opening).

External links

• Prof. Nagesh Havanur, The Latvian Gambit Revisited, Part One, chessville.com.
• Prof. Nagesh Havanur, The Latvian Gambit Revisited, Part Two, chessville.com.
• Latvian Gambit analyzed by correspondence chess players, Wikichess.
• Le gambit letton.

Fantasy name generators are programs that use a computer algorithm to create a fantasy name at random probability, usually for use in a role-playing game. They have been around since at least 1994. Early fantasy name generators often generated nonsense, creating names such as “Rsi’sskoo” or “Gbbtti”. Modern fantasy name generators are typically better at creating usable names.

Phase response is the relationship between the phase of a sinusoidal input and an output signal passing through any device which accepts an input and produces an output signal such as an amplifier or a filter.

Amplifiers, filters, and other devices, are often categorized by their amplitude and/or phase response. The amplitude response, is the ratio of output amplitude to input, usually as a function of frequency.
Similar, phase response is phase of the output, with the input as a reference. The input is define as zero phase. Phase response is not limited to zero degrees to 360 degrees, as phase can accumulate beyond 360.

Uan Muhuggiag is a place in the central Sahara, and the name of the mummy of a small boy found there in 1958 by Professor Fabrizio Mori. The mummy displays a highly sophisticated mummification technique, and at around 5,500 years old is older than any comparable Ancient Egyptian mummy.

The African culture that produced the mummy were cattle herders, and occupied much of North Africa, at a time when the Sahara was a savannah. (A change in the Earth’s axis subsequently led to the climatic changes which created the modern Sahara desert.) Other links with later Egyptian culture have also been found, including the representation in rock art of dog-headed human figures (resembling Anubis), and a type of pottery decoration later found in the southern Nile valley.

In group theory, Tietze transformations are used to transform a given presentation of a group into another, often simpler presentation of the same group. These transformations are named after Heinrich Franz Friedrich Tietze who introduced them in a paper in 1908.

A presentation is in terms of generators and relations; formally speaking the presentation is a pair of a set of named generators, and a set of words in the free group on the generators that are taken to be the relations. Tietze transformations are built up of elementary steps, each of which individually rather evidently takes the presentation to a presentation of an isomorphic group. These elementary steps may operate on generators or relations, and are of four kinds.

1. Adding a Relation

If a relation can be derived from the existing relations then it may be added to the presentation without changing the group. Let G=< x | x³=1 > be a finite presentation for the cyclic group of order 3. Multiplying x³=1 on both sides by x³ we get x⁶ = x³ = 1 so x⁶ = 1 is derivable from x³=1. Hence G=< x | x³=1, x⁶=1 > is another presentation for the same group.

2. Removing a Relation

If a relation in a presentation can be derived from the other relations then it can be removed from the presentation without affecting the group. In G=< x | x³=1, x⁶=1 > the relation x⁶ = 1 can be derived from x³=1 so it can be safely removed. Note, however, that if x³=1 is removed from the presentation the group G=< x | x⁶=1 > defines the cyclic group of order 6 and does not define the same group. Care must be taken to show that any relations that are removed are consequences of the other relations.

3. Adding a Generator

Given a presentation it is possible to add a new generator that is expressed as a word in the original generators. Starting with G=< x | x³=1 > and letting y=x² the new presentation G=< x,y | x³=1, y=x² > defines the same group.

4. Removing a Generator

If a relation can be formed where one of the generators is a word in the other generators then that generator may be removed. In order to do this it is necessary to replace all occurrences of the removed generator with its equivalent word. The presentation for the elementary abelian group of order 4, G=< x,y,z | x = yz, y²=1, z²=1, x=x^-1 > can be replaced by G=< y,z | y²=1, z²=1, (yz)=(yz)^-1 > by removing x.

Examples

Let G=< x,y | x³=1, y²=1, (xy)²=1 > be a presentation for the symmetric group of degree three. The generator x corresponds to the permutation (1,2,3) and y to (2,3). Through Tietze transformations this presentation can be converted to G=< y, z | (zy)³=1, y²=1, z²=1>, where z corresponds to (1,2).

References

• Roger C Lyndon, Paul E Schupp, Combinatorial Group Theory, Springer, 2001. ISBN 3-540-41158-5.

Fantasy name generators are programs that use a computer algorithm to create a fantasy name at random probability, usually for use in a role-playing game. They have been around since at least 1994. Early fantasy name generators often generated nonsense, creating names such as “Rsi’sskoo” or “Gbbtti”. Modern fantasy name generators are typically better at creating usable names.

BPM

is the People’s Republic of China’s national time signal service, operated by the Chinese Academy of Sciences.

It broadcasts at 2.5, 5, 10, and 15 MHz.

BPM is idiosyncratic in that it transmits UT1 time between minutes 25 through to 29 and 55 through to 59, which creates an odd click-beep effect when heard below a stronger time signal station such as WWV.

In mathematics, polynomials in more than one variable do not form a Euclidean domain, so it is not possible to construct a true division algorithm; but an approximate multivariate division algorithm can be constructed.

Given a polynomial g, polynomials (f₁, …, f_m) and an order on the monomials in k[x₁, …, x_n], we construct the reduction of g modulo f₁, …, f_m by repeatedly applying the following procedure until doing so leaves g unchanged:

Let a_i denote the leading term of f_i with respect to our ordering. Take the smallest i such that the a_i divides some term of g. Let h be the largest (again with respect to the monomial ordering) term of g which is divisible by a_i, and replace g by g − (h / a_i )f_i.

Each time g changes in this procedure, it gets strictly smaller relative to the partial lexicographic order on polynomials where h >h’ iff the largest monomial which is in exactly one of h and h’ is in h. Therefore this process will eventually terminate.

Notes

• Rather distressingly, the final value of g can depend on the order in which the original f₁, …, f_m are given. In fact, it is possible that the algorithm will yield 0 in some cases, but nonzero values in others. This problem disappears when working with a Gröbner basis.

• When n = 1 this procedure collapses down to the standard Euclidean algorithm for polynomials.

Fantasy name generators are programs that use a computer algorithm to create a fantasy name at random probability, usually for use in a role-playing game. They have been around since at least 1994. Early fantasy name generators often generated nonsense, creating names such as “Rsi’sskoo” or “Gbbtti”. Modern fantasy name generators are typically better at creating usable names.

The open-loop gain of an operational amplifier is the gain obtained when no feedback is used in the circuit.
Open loop gain is usually exceedingly high; in fact, an ideal operational amplifier has infinite open-loop gain. Typically an op-amp may have an open-loop gain of around <math>10^9</math>. Normally, feedback is applied around the op-amp so that the gain of the overall circuit is defined and kept to a figure which is more usable. However the very high gain of the op-amp enables considerable levels of feedback to be applied to achieve required performance. The open-loop gain of an operational amplifier falls very rapidly with increasing frequency. Along with slew rate, this is one of the reasons why operational amplifiers have limited bandwidth.

In mathematics, the Eisenstein ideal is a certain ideal in the endomorphism ring of the Jacobian variety of a modular curve. It was introduced by Barry Mazur in 1977, in studying the rational points of modular curves. The endomorphism ring in question is closely associated with a Hecke algebra, and the name comes from the way the definition in detail follows the action of Hecke operators on Eisenstein series.

Let N be a positive integer, and define

J₀(N) = J

be the Jacobian variety of the modular curve

X₀(N) = X.

There are endomorphisms T_l of J for each prime number l not dividing N. These come from the Hecke operator, considered first as an algebraic correspondence on X, and from there as acting on divisor classes, which gives the action on J. There is also an involution w. The Eisenstein ideal, in the (unital) subring of End(J) generated as a ring by the T_l, is generated as an ideal by the elements

T_l − l + 1

for all l not dividing N, and by

w

+ 1.

References

• Mazur, B. Modular curves and the Eisenstein ideal. Inst. Hautes Études Sci. Publ. Math. No. 47 (1977), 33–186 (1978).

Lasca (also called Laska or Laskers) is a draughts (or checkers) variant, invented by the second World Chess Champion Emanuel Lasker (1868–1941).

The game is played on a 7×7 board; as with draughts and most descendant games, play takes place only on alternating squares, so that only 25 of the 49 squares are actually used. The playing pieces are known initially as “soldiers”; when they reach the last row of the board, they become “officers”, with the same ability as kings in English draughts to move and jump backwards.

The major difference between Lasca and other draughts variants is that instead of pieces being removed from the board when they are jumped, they are placed under the piece that jumped them, forming a “column”. A column is under the control of the player whose piece is on top, and has the move and jump capabilities of that piece (so that, for instance, a column with a Black officer on top is under Black’s control, and can move and jump in either direction.) If a column is itself jumped, only the top piece is removed to go under the column doing the jumping.

There are a few other changes in the rules, as well. Capturing is mandatory when possible; this means that a clever player may be able to force his opponent to capture several pieces of his color, then capture his opponent’s piece from the top, leaving a powerful column composed of several pieces of his own color. Also, the game is won when one player (a) leaves his opponent with no legal way to move (b) has captured all his opponent’s pieces or (c) when the opposing player resigns.

External links

• The game of Lasca - detailed information about the rules and history of the game.

Fantasy name generators are programs that use a computer algorithm to create a fantasy name at random probability, usually for use in a role-playing game. They have been around since at least 1994. Early fantasy name generators often generated nonsense, creating names such as “Rsi’sskoo” or “Gbbtti”. Modern fantasy name generators are typically better at creating usable names.

Pneumatic flow control is the use of air as a control medium, or as the controlled medium, in which one medium controls the flow of another.

Pneumatic flow control taxonomy

There are two possible pneumatic flow controls: those that are controlled by pneumatics, and those that control pneumatics.

Pneumatically controlled valves

Pneumatically controlled valves are valves that are controlled by pressurized air.
These may include water flow valves that are controlled by compre ssed air.

Pneumatically controlling valves

Pneumatically controlling valves are valves that control the flow of pressurized air. Another medium such as water (hydraulics) or electricity, for example, may be used to control the valves.

In some cases, the valves are operated manually rather than automatically.

A Bruceton Analysis is one way of analyzing a sensitivity test of explosives as described originally by Dixon and Mood in 1948. Also known as the “Up and Down Test,” a Bruceton analysis relies upon two parameters: first stimulus and step size. A stimulus is provided to the sample, and the results noted. If a positive result is noted, then the stimulus is decremented by the step size. If a negative result occurs, the stimulus is increased. The test continues with each sample tested at a stimulus 1 step up or down from the previous stimulus if the previous result was negative or positive.

The results are tabulated and analyzed via Bruceton analysis, a simple computation of sums that can be performed by pencil and paper, to provide estimates of the mean and standard deviation. Confidence estimates are also produced. Another analysis method is the Neyer d-optimal test and its related Likelihood Ratio Analysis method. These methods are often called the Neyer test.

References

• J. W. Dixon and A. M. Mood (1948), “A Method for Obtaining and Analyzing Sensitivity Data,” Journal of the American Statistical Association, 43, pp. 109-126.

• B. T. Neyer (1994), “A D-Optimality-Based Sensitivity Test,” Technometrics, 36, pp. 61-70.

See also

• Safety Testing of Explosives

Single-frequency signaling (SF) is signaling (in telephony) in which dial pulses or supervisory signals are conveyed by a single voice-frequency tone in each direction.

An SF signaling unit converts E&M signaling to a format (characterized by the presence or absence of a single voice-frequency tone), which is suitable for transmission over an ac path, e.g., a carrier system. The SF tone is present in the idle state and absent during the seized state. In the seized state, dial pulses are conveyed by bursts of SF tone, corresponding to the interruptions in dc continuity created by a rotary dial or other dc dialing mechanism.

The SF tone may occupy a small portion of the user data channel spectrum, e.g., 1600 Hz or 2600 Hz (”in-band” SF signaling), usually with a notch filter at the precise SF frequency, to prevent the user from inadvertently disconnecting a call if user data has a sufficiently strong spectral content at the SF frequency, a condition known as talk-off. The SF tone may also be just outside the user voice band, e.g., 3600 Hz.

The Defense Data Network (DDN) transmits dc line signaling pulses or supervisory signals, or both, over carrier channels or cable pairs on a four wire circuit basis using a 2600 Hz signal tone. The conversion into tones, or vice versa, is done by SF signal units.

SF was developed in the early 20th century and standardized in middle century. It declined in the 1970s due to the adoption of T-carrier, and largely abandoned late in the century in favor of common channel signalling.

The pycnometer (from the Greek puknos, meaning “density”, also called pyknometer or specific gravity bottle), is a flask with a close-fitting ground glass stopper with a fine hole through it, so that a given volume can be accurately obtained.  This enables the density of a fluid to be measured accurately, by reference to an appropriate working fluid such as water or mercury, using an analytical balance.

If the flask is weighed empty, full of water, and full of a liquid whose specific gravity is desired, the specific gravity of the liquid can easily be calculated. The particle density of a powder, to which the usual method of weighing cannot be applied, can also be determined with a pycnometer. The powder is added to the pycnometer, which is then weighed, giving the weight of the powder sample. The pycnometer is then filled with a liquid of known density, in which the powder is completely insoluble. The weight of the displaced liquid can then be determined, and thence the specific gravity of the powder.

The pycnometer is used in ISO standard: ISO 1183-1:2004, and ASTM standard: ASTM D854.

The Galapagos Rise is a divergent boundary located between the South American coast and the triple junction of the Nazca Plate, the Cocos Plate, and the Pacific Plate. The volcanically active Galapagos Islands exist on a hotspot above the Galapagos Rise. The Galapagos Microplate is a small separate plate on the rise just to the southeast of the triple junction.

The Cocos Ridge trends northeasterly from the Galapagos to the coast of Costa Rica and Panama. The Carnegie Ridge trends almost due east to the Ecuadorian coast.

The Galapagos Rise is a currently active ridge. Fernandina Volcano on Fernandina Island, the most westerly island of the chain erupted on May 12, 2005 ejecting a column of ash that rose to a height of seven km from a fissure on the west side of the volcano. Volcanic ash fell on neighboring Isabela Island. Alcedo Volcano on Isabela Island last erupted in the 1950s.

References

• Galapagos geology - Cornell - map of the Rise
• Nasa Earth Observatory - View of Fernandina Volcano from space

A rhythmic gesture is a durational pattern which, in contrast to a rhythmic unit, does not occupy a period of time equivalent to a pulse or pulses on an underlying metric level. (DeLone et al. (Eds.), 1975, chap. 3)

They may be described according to their beginnings and endings or as to the rhythmic units they contain. Beginnings on a strong pulse are thetic, a weak pulse, anacrustic, and those beginning after a rest or tied-over note are called initial rest. Endings on a strong pulse are strong, a weak pulse, weak, and those which end on a strong or weak upbeat are upbeat. (DeLone et al. (Eds.), 1975, chap. 3)

References

• DeLone et al. (Eds.) (1975). Aspects of Twentieth-Century Music. Englewood Cliffs, New Jersey: Prentice-Hall. ISBN 0-13-049346-5.

In genetics, a nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and possibly a truncated, and often nonfunctional protein product.

Simple example

For example, given the following sense DNA sequence, the corresponding mRNA transcript, and the translated protein product:

    DNA: ATG ACT CAC CGA GCG CGA AGC TGA
   mRNA: AUG ACU CAC CGA GCG CGA AGC UGA
Protein: Met Thr His Arg Ala Arg Ser Stop

Suppose that a nonsense mutation were introduced at the fourth triplet in the DNA sequence (CGA) causing the cytosine to be replaced with thymine, yielding TGA in the DNA sequence. Since TGA is transcribed as UGA, the resulting transcript and protein product would be:

   mRNA: AUG ACU CAC UGA CGC CGU AGC UGA
Protein: Met Thr His Stop

The remaining codons of the mRNA are not translated into amino acids because the stop codon is prematurely reached during translation. This can yield a truncated abbreviated protein product, which quite often lacks the functionality of the normal, non-mutant protein.

Nonsense-mediated mRNA decay

Despite an expected tendency for premature termination codons to yield shortened polypeptide products, in fact the formation of truncated proteins does not occur often in vivo. Many organisms — including humans and lower species, such as yeast — employ a nonsense-mediated mRNA decay pathway, which degrades mRNAs containing nonsense mutations before they are translated into nonfunctional polypeptides.

Pathology associated with nonsense mutations

Nonsense mutations can cause a genetic disease by damaging a gene responsible for a specific protein, for example, distrophin in Duchenne muscular dystrophy. The same disease may, however, be caused by other kinds of damage to the same gene. Examples of diseases in which nonsense mutations are known to be among the causes include:

• Cystic fibrosis (caused by mutations in the cystic fibrosis transmembrane conductance regulator gene).

• Duchenne muscular dystrophy (distrophin)

• Beta thalassaemia

• Hurler syndrome

An experimental drug known as PTC124 may be useful in treating some cases of each of the above diseases (that is, the cases caused by a nonsense mutation). PTC124 is scheduled to enter the final phase of clinical trials in 2007.[1]

External links and references

• Mutations
• Nonsense mutation (Medical dictionary)
• Gatfield D, Unterholzner L, Ciccarelli FD, Bork P, Izaurralde E., “Nonsense-mediated mRNA decay in Drosophila: at the intersection of the yeast and mammalian pathways”. EMBO J. 2003 Aug 1;22(15):3960-70. PMID 12881430
• Welch EM, et al., “PTC124 targets genetic disorders caused by nonsense mutations”, Nature 447, 87-91 (3 May 2007) (DOI: 10.1038/nature05756)

End distortion: In start-stop teletypewriter operation, the shifting of the end of all marking pulses, except the stop pulse, from their proper positions in relation to the beginning of the next start pulse.

Shifting of the end of the stop pulse is a deviation in character time and rate rather than an end distortion.

Spacing end distortion is the termination of marking pulses before the proper time. Marking end distortion is the continuation of marking pulses past the proper time.

The magnitude of the distortion is expressed as a percentage of an ideal pulse length.

A power-on reset (PoR) generator is a microcontroller or microprocessor peripheral that generates a reset signal when power is applied to the device. It ensures that the device starts operating in a known state.

In VLSI devices, the power-on reset (PoR) is an electronic device incorporated into the integrated circuit that detects the power applied to the chip and generates a reset impulse that goes to the entire circuit placing it into a known state.
A simple PoR is composed by a RC device that charges with the rising of the supply voltage. A schmitt trigger is used so that the rising charged voltage of the RC network generates an impulse. This impulse is generated based on the two threshold voltages of the schmitt trigger. When the input voltage at the schmitt trigger coming from the RC network reaches the first threshold voltage the output of the schmitt trigger switches so that it generates the first edge of the input. The charging of the RC network should be long enough so that the PoR can reset all the internal circuits before the charging voltage reaches the other threshold voltage of the schmitt trigger and the output to switch back.

One of the issues with using RC network to generate PoR pulse is the sensitivity of the R and C values to the power-supply ramp characteristics. When the power supply ramp is rapid, the R and C values can be calculated so that the time to reach the switching threshold of the schmitt trigger is enough to apply a long enough reset pulse. When the power supply ramp itself is slow, the RC network tends to get charged up along with the power-supply ramp up. So when the input schmitt stage is all powered up and ready, the input voltage from the RC network would already have crossed the schmitt trigger point. This means that there might not be a reset pulse supplied to the core of the VLSI…

Ceruloplasmin (or caeruloplasmin) is officially known as ferroxidase or iron(II):oxygen oxidoreductase.

Function

It is an enzyme () synthesized in the liver containing 8 atoms of copper in its structure. Ceruloplasmin carries 90% of the copper in our plasma. The other 10% is carried by albumin, albumin may be confused at times to have a greater importance as a copper carrier because it binds copper less tightly than ceruloplasmin. Ceruloplasmin exhibits a copper-dependent oxidase activity, which is associated with possible oxidation of Fe²⁺ (ferrous iron) into Fe³⁺ (ferric iron), therefore assisting in its transport in the plasma in association with transferrin, which can only carry iron in the ferric state.

Pathology

Like any other protein, levels drop in patients with hepatic disease due to reduced synthesizing capabilities.

Mutations in the ceruloplasmin gene can lead to the rare genetic human disease aceruloplasminemia, characterized by iron overload in the brain, liver, pancreas, and retina.

Interpretation

Decreased levels

Lower-than-normal ceruloplasmin levels may indicate:

• Menkes disease (Menke’s kinky hair syndrome) (very rare)
• Wilson’s disease (a rare copper storage disease)
• Overdose of vitamin C
• Copper deficiency
• Aceruloplasminemia

Elevated levels

Greater-than-normal ceruloplasmin levels may indicate:

• pregnancy
• lymphoma
• acute and chronic inflammation (it is an acute-phase reactant)
• rheumatoid arthritis

Sealed systems are computer systems that are designed to be supplied as a sealed unit. The major benefits are security, reliability, ease of installation and upgrade, and locked down so users can’t make changes that would compromise the integrity of the system. Many techniques may be used to build a sealed system. One obvious approach is custom hardware but this can be expensive.

The term sealed systems was coined by Tailored Computers in Portland, Oregon. Their goal was to build sealed systems using inexpensive, off-the-shelf PCs. Their design takes advantage of features of the Linux operating system.

Properly-designed sealed systems are highly-resistant to attack. All programs and static data are placed in immutable storage where they can’t be modified and new programs and data cannot be added. Data that must be changed, such as configuration data and user data files, is kept in mutable storage. Any attacks that seek to modify programs or plant additional files in immutable storage will fail.

Attacks that try to modify data in mutable storage are possible. However, well-designed sealed systems will prevent programs from executing from mutable storage and they won’t put system-critical configuration data in mutable storage.

The segregation of programs and data into immutable and mutable storage makes some operations, such as backing up data, easier. The system can be easily backed up just by backing up all of mutable storage.

External links

• Official project page for Sealed Systems

A sonic user interface or SUI is a human-machine interface that uses sound as the medium of communication. Unlike a GUI or graphical user interface, the user is only required to speak or make sounds into a microphone or other audio input device and listen for the output on a loudspeaker, headphone set or other audio output device.

Fantasy name generators are programs that use a computer algorithm to create a fantasy name at random probability, usually for use in a role-playing game. They have been around since at least 1994. Early fantasy name generators often generated nonsense, creating names such as “Rsi’sskoo” or “Gbbtti”. Modern fantasy name generators are typically better at creating usable names.

Digital painting is an emerging artform in which traditional painting techniques such as watercolor, oils, impasto, etc. are applied using digital tools by means of a computer, a digitizing tablet and stylus, and software. Digital painting differs from other forms of digital art, particularly computer-generated art, in that it does not involve the computer rendering from a model. The artist uses painting techniques to create the digital painting directly on the computer.

The main difference between digital and traditional painting is the non-linear process. That is, an artist can often arrange their painting in layers that can be edited independently. Also, the ability to undo and redo strokes frees the artist from a linear process. But digital painting is limited in how it employs the techniques and study of a traditional painter because of the surface differences and lack of physicality. The digital artist has at their disposal several tools not available to the traditional painter. Some of these include: a virtual palette consisting of millions of colors, almost any size canvas or media, and the ability to take back mistakes, as well as erasers, pencils, spray cans, brushes, combs, and a variety of 2D and 3D effect tools. A graphics tablet allows the artist to work with precise hand movements simulating a real pen and drawing surface.

Digital painting thrives mostly in production art. It is most widely used in conceptual design for film, television and video games. Digital painting software such as Corel Painter, Adobe Photoshop, ArtRage, GIMP, and openCanvas give artists a similar environment to a physical painter: a canvas, painting tools, mixing palettes, and a multitude of color options.
There are various types of digital painting, including impressionism, realism, and watercolor.

See also

• Digital artist
• Digital photography
• Digital art
• Vector graphics

A rotary combination lock is a lock commonly used to secure safes and as an unkeyed padlock mechanism. This type of locking mechanism consists of a single dial which must be rotated left and right in a certain combination in order to open the lock.

Contained inside the mechanism are discs, usually three, with notches that must be aligned to allow for a release of the piece holding the lock in place, and the lock to open. The position of the discs are manipulated by turning the dial left and right; on the dial is a catch - a sort of nub - and on each side of the discs is also a small catch. As the dial rotates, there will not be enough space for the catch on the dial to pass the catch on that side of the disc, and so the disc will begin to rotate with the dial. As this disc rotates, its catch will in turn begin rotating the next disc in a similar fashion. Once all discs and the dial are rotating together, the dial is rotated until the last disc is in place and the notch is in the proper positioning, then by rotating the dial in the other direction, the catches will all disconnect, starting from the dial to the first disc and so on until they connect from the other side and the discs begin to rotate together by the same method but in the opposite direction. In this way, the remaining discs are able to rotate and change their position without further disturbing the last disc. The process is completed back and forth until all discs are in place, and the lock is released.

See also

• Combination lock

External links

• How rotary combination locks work
• Rotary combination lock cracker
• Installing rotary combination locks
• Matt Blaze’s paper Safecracking for Computer Scientists contains a detailed description, with photographs, of rotary combination locks and their security concerns

PANA may be:

• The Panafrican News Agency, based in Senegal
• A former name of the Islamic Republic News Agency, based in Iran
• The Protocol for carrying Authentication for Network Access
• Pana can also be related to myths and legends of America
• PANA in Telecommunications refers to a Plain Analog Loop also known as a Dry pair, or BANA (basic analog loop) amongst other terms see BANA

High Cross is the name of a number of locations in the United Kingdom:

England

• High Cross, Cambridgeshire
• High Cross, Cornwall
• High Cross, East Sussex
• High Cross, Hampshire
• High Cross, Hertfordshire
• High Cross, Leicestershire
• High Cross, Warwickshire
• High Cross, West Sussex

Wales

• High Cross, Newport, Wales

Donald Henry Tuck (born 1922 in Australia) is a bibliographer of science fiction and fantasy. His works were the most extensive produced since the early work of Everett F. Bleiler. The Handbook of Science Fiction and Fantasy was awarded a Special Hugo Award in 1962, while The Encyclopedia of Science Fiction and Fantasy won both a 1979 World Fantasy Award and a 1984 Hugo Award (for volume three).

Bibliography

• A Handbook of Science Fiction and Fantasy (1954)
• The Encyclopedia of Science Fiction and Fantasy - published in three volumes:
  • Vol 1: Who’s Who, A-L (1974)
  • Vol 2: Who’s Who, M-Z (1978)
  • Vol 3: Miscellaneous (1983)

External links

Leicester’s Clock Tower is a major landmark and popular meeting point in the city centre. It is located roughly in the middle of the area inside the ring-road, and is at the point where five major streets (Gallowtree Gate, Humberstone Gate, Belgrave Gate, Church Gate and High Street) meet, and also close by to the junction with Cheapside.

The Clock Tower was constructed in 1868, as a centre piece for a traffic island for the increasingly busy Haymarket/Eastgates junction (its business grew with Leicester’s expansion and with the adoption of what is now the A6 as the primary road to London). A competition was held for the design, this was won by Joseph Goddard. The tower was built mostly in Ketton stone. Funding was provided largely by private subscription, with the initial origanisation being from John Burton.

Officially a memorial, the Clock Tower has four statues of sons of Leicester, one at each corner. The figures are Simon de Montfort, William Wyggeston (spelt ‘William Wigston’ on the tower itself), Thomas White and Gabriel Newton.

Before the construction of the Clock Tower the site had been used for and Assembly Room building, built in 1750, which was re-used and divided as shops in 1801. These had been demolished in 1862.

Originally a traffic island at a 5-way junction, the Clock Tower was later converted to be the centre-piece of a roundabout, in 1926. Pedestrianisation has now led to Humberstone Gate and Gallowtree Gate being shut off from traffic, and the Clock Tower is now bounded by a road solely on the northern side.

Leicester City Council has recently unveiled plans to greatly enhance the Clock Tower through extensive de-cluttering to achieve a restored landmark public space at the heart of the city. The result is to be a significant public square with a cosmopolitan character. “Leicester City Council - Clock Tower/East Gates” “Leicester City Council - Streets & Spaces (Stage 3) - Clock Tower and East Gates” Construction on the new site is underway as of September 2007.

The Clock Tower is the de rigueur meeting place in the city centre.

References

External links

• Clock Tower according to the City Council
• Image of the Clock Tower from 1963, from the BBC

In biology, the term crosstalk refers to the phenomenon that signal components in signal transduction can be shared between different signal pathways and responses to a signal inducing condition (e.g., stress) can activate multiple responses in the cell/the organism.

See also

• Cell Signaling Networks
• Cell signaling
• Molecular Cellular Cognition

Device may refer to:

Computing and electronics

• Computer hardware
• Peripheral device, any device attached to a computer that expands its functionality
• Device file, an interface for a device driver
• Information appliance, a device, such as a cell phone, that focuses on handling a particular type of information and related tasks
• Display device, a device that graphically displays text or images
• Electronic component

Other uses

• Measuring instrument
• Machine
• Tool
• Device (band)
• Rhetorical device, a technique used in writing or speaking
• Part of a coat of arms
• An attachment to a medal’s ribbon denoting special service, participation in a battle, or additional awards

See also

• Devise
• Devizes

High Ash Church of England Combined School is a mixed Church of England primary school in Great Brickhill, Buckinghamshire.

It is a voluntary controlled school, which takes children from the age of 4 through to the age of 12. The school has approximately 240 pupils.

It is one of several Buckinghamshire schools which host mobile phone masts. Contracts between Buckinghamshire County Council and various mobile phone operators generate an income of £145,000 per annum, of which about £59,000 comes from contracts for masts that are installed in schools.

References

External links

• School website
• Ofsted Report
• DfES Performance Tables

University of Science and Technology Liaoning (辽宁科技大学) is a university in Liaoning, China under the provincial government.

History and profile

University of Science and Technology Liaoning was originally conceived in 1948, former Anshan Institute of Iron and Steel. Or in Chinese, “An Gang Yuan”.

The University has 15 faculties (schools or departments). It provides 35 programs of undergraduate, 11 high-level special professional programs and 17 graduates programs. There are 14,000 students enrolled currently.