Aarushhh/wikipedia-simple-splitted huggingface dataset:
Criss Angel Mindfreak is an American television program. The program is hosted by illusionist Criss Angel. Angel performs many different types of stunts and illusions on the program such as street magic, levitation, and setting himself on fire. The program was first shown on July 20, 2005. It is shown and distributed by the A&E network.

Other websites 
 Official Criss Angel website
 Official Criss Angel Mindfreak TV Series website at A&E
 Titles & Air Dates Guide of Criss Angel Mindfreak at epguides.com

2005 American television series debuts
2010 American television series endings
2000s American television series
2010s American television series
American reality television series
Magic
English-language television programs
A piano trio is a group of three instruments including a piano. Usually it is a piano, a violin and a cello. This combination of instruments has been a very popular form of chamber music from the Classical music period onwards. A piano trio can also mean a piece of music written for a piano trio to play.

Other combinations of piano with two instruments are often called by the featuring wind instrument. For example: Mozart wrote a trio for piano, clarinet and viola which is usually called a “clarinet trio”. Brahms wrote a trio for piano, violin and French horn which is usually called a “horn trio”.

Music for three people to play at one piano is called music for piano six hands.

Famous music for piano trio 

Haydn, Mozart and Beethoven all wrote several piano trios for the traditional combination of piano, violin and cello. Beethoven’s last piano trio has the nickname Archduke because it was written for the Archduke Rudolph. Franz Schubert wrote two beautiful piano trios.
In the Romantic period some of the best piano trios were written by Felix Mendelssohn, Antonín Dvořák, César Franck and Pyotr Tchaikovsky.

In the 20th century Maurice Ravel and Dmitri Shostakovich each wrote a famous piano trio.

Famous piano trios 

Alfred Cortot, Jacques Thibaud and Pablo Casals were world famous musicians who played and recorded piano trios in the early 20th century.
During the second half of the 20th century the Beaux Arts Trio were the best known group. Today there are many young musicians who play piano trios, including three Japanese sisters called the Fujita Piano Trio who play a lot of their music all from memory.

Musical groups
Piano
Franz Grillparzer (born Vienna, 15 January 1791 – died Vienna, 21 January 1872) was an Austrian dramatist and poet. His dramas include three plays (a “trilogy”) called Das Goldene Vliess (The Golden Fleece).

Works 
Two other famous plays are Des Meeres und der Liebe Wellen (The Waves of the Sea and of Love) and Der Traum, ein Leben (The Dream, a Life).  Although he said he was not interested in prose his short story Der arme Spielmann (The poor minstrel) is probably the best known of his works and one of the best short stories of the 19th century.  Grillparzer wrote the funeral speech for Beethoven's funeral in 1827.

Legacy

An Austrian pastry is named after him: the Grillparzertorte.

References

Other websites

1791 births
1872 deaths
Austrian poets
Writers from Vienna
Pastry is the dough from which some baked products are made. Pastry dough is rolled out thinly and used as a base for baked products. It is made from ingredients such as flour, sugar, milk, butter, shortening, baking powder, and/or eggs. Common pastry dishes include pies, tarts, quiches and pasties.

Pastry is also the name given to various kinds of baked products. Small cakes, tarts and other sweet or savoury baked products are called "pastries." 

Greek food such as Spanakopita are made from pastries.

Related pages 
Cookie

References 

Baked foods‎
Johann Georg Albrechtsberger (born 3 February 1736 in Klosterneuburg near Vienna; died 7 March 1809 in Vienna) was an Austrian composer, organist, music theorist and music teacher.  He is most known today because he was Beethoven’s teacher for a time.

Life
From the age of seven, Albrechtsberger was a choirboy.  He had lessons in organ and music theory.  As an adult, he had several jobs in churches in small towns.  He became Kapellmeister at St Stephen’s Church, Vienna in 1793.  This was the best job for a church musician in the empire.
Writing music
Albrechtsberger wrote hundreds of compositions. He wrote most of them before he got the job in Vienna.  He wrote in a classical style. Albrechsberger enjoyed doing things with music which were not normally done. He would ask string players to tune their strings in different ways (called “scordatura”). He would also write slow movements with muted strings.  As well as classical sonatas he wrote lots of fugues.  Several people, including Mozart, thought of him as the greatest organist in the world.

Teaching
Albrechtsberger was a very important music teacher.  Joseph Haydn thought he was the best teacher in Vienna.  He was very interested in contrapuntal music of the Baroque period. He copied many fugues by Bach and other composers.
When Beethoven was a young man, he had some composition lessons from Joseph Haydn.  When Haydn was going to travel to England for several months, he asked Albrechtsberger to teach Beethoven while he was gone. These lessons took place from 1793 to 1795.  A few years later, Albrechtsberger said about Beethoven that “he learned absolutely nothing and will never accomplish anything decent”.  Beethoven said that Albrechtsberger was a “musical pedant”.  However, Beethoven still studied Albrechtsberger’s books on music theory.  The string quartets which Beethoven wrote near the end of his life show the influence of Albrechtsberger.

References 

1736 births
1809 deaths
Austrian composers
Classical era composers
Music theorists
Austrian organists
People from Lower Austria
Fidelio is an opera in two acts by Ludwig van Beethoven. It is Beethoven's only opera. The German libretto is by Joseph Sonnleithner based on a French story.  The opera tells how Leonore, disguised as a prison guard called "Fidelio", rescues her husband Florestan from death in a political prison.

Fidelio is an example of a “rescue opera”, a type of opera which was popular at the time. The hero (or heroine) has to fight against cruel people in order to rescue a lover.  It was written at the time of the French Revolution.  At this time,  ideas about freedom and peace were being talked about by everyone, and this led to wars all over Europe.  The famous Prisoners’ Chorus is a song for freedom, just like the last movement of his Ninth Symphony.
Beethoven spent some time working on the opera before he was completely happy with it. The first time it was performed (in 1805) it was a three-act opera called Leonore. There were a lot of French military officers in the audience and they thought they were being criticised.  In 1806 it was performed again with two acts and a new overture (now known as "Overture: Leonore No. 3").  But arguments between Beethoven and the theatre management meant there were no more performances.  Eight years later Beethoven revised his opera again.  This time it was called Fidelio, and it was a great success.  It has remained a famous opera ever since.

Plot 
The setting is a Spanish state prison, a few miles from Seville, in the late 18th century.

Act I
Act I 

Jaquino is a prison guard.  He wants to marry Marzelline, the daughter of Rocco who is the warden of the prison.  But Marzelline has just fallen in love with someone she thinks is a man called Fidelio.  Actually Fidelio is a woman who has dressed up as a man so that she can get into the prison where her husband Florestan is a prisoner (he has been arrested for political reasons).  She is pretending to return Marzelline’s love so that she can find a way of rescuing Florestan.  Rocco says he is happy for Marzelline to marry Fidelio.  Fidelio (Leonore) says she will help Rocco with his job of looking after the prisoners.  Rocco says she can do this, but there is one prisoner she is not allowed to guard.  He has been locked up alone for two years.  Leonore thinks it may be her husband, but she is not sure.
Don Pizarro, the military governor of the prison, hears that the prison is going to be looked at by inspectors who make sure that the prison is being properly managed.  He knows that he should not have locked Florestan up, so decides to kill him before the inspection starts.  He asks Rocco to dig the grave so that he can get rid of the body quickly.  Rocco does not want to do this, but has to agree.

Leonore lets the prisoners have a walk in the garden.   Rocco tells Leonore that he must help him dig the grave.  Rocco is very cross that the prisoners are walking in the garden, but Rocco says they should be allowed because it is the King’s name-day.  Rocco says they should be locked up again. So he locked them again.

Act II

Florestan sits alone in his cell.   In his mind he imagines an angel who looks like his wife who is telling him to come to Heaven.
Leonore goes with Rocco to the prisoner.  She is still not sure whether it is her husband.  She gives him some bread.  When Pizarro comes he gets ready to kill Florestan, but Leonore stands between them and tells Pizarro she will shoot him if he comes nearer.  A trumpet is heard playing a fanfare because the Minister is arriving.

Outside the prison the Minister says that all the prisoners are now free.  He is horrified to find Florestan among the prisoners, because he is his friend.  The crowd ask for Pizarro to be punished.  Leonore frees her husband from his chains and the crowd say that she is a great heroine.
The Overtures
Beethoven made several changes to the opera at different times.  This included writing four different overtures.  They are called "Leonore 1", "Leonore 2", "Leonore 3" and "Fidelio".  The overture "Fidelio" is the one that is normally heard now at the beginning of the opera.  "Leonore 2" was the overture performed at the first performance in 1805.  "Leonore 3", composed in 1806, is the most famous of the overtures.  "Leonore 1" may have been written in 1805, or it may have been intended for a performance in 1807 in Prague which never took place".  Sometimes the "Leonore 3" overture is played during Act II between the two scenes.  However, many people think it does not work dramatically there.  It is usually heard today as a separate concert piece.  The overture "Fidelio" was composed for performances of the opera in 1814.

References

Compositions by Ludwig van Beethoven
1800s operas
1805 works
"Für Elise" (German for For Elise) is the common name of the song "Bagatelle in A minor." It was written for the piano by the composer Ludwig van Beethoven in 1810. The song is thought to be written for Therese, a woman that Beethoven wanted to marry in 1810. It is believed that his handwriting was not translated correctly when the song was transcribed. This caused the piece to be known as "Fur Elise" rather than "Fur Therese". 

The piece of music was not published until 1865. This was a long time after the death of Beethoven. It is one of the most well-known pieces of piano music in the world.

Form 
The piece is in rondo form. There is a main section (A) which appears three times. Between these three sections there are two other sections (B and C), so the form of the piece can be described as: A B A C A.
The main section has a time signature of 3/8. It is based on arpeggios which flow from one hand to the other. This is the section that many beginner pianists want to play. The two middle sections are harder to play at the correct speed. They have fast scales, arpeggios and left hand demisemiquavers (32nd notes).

References
 Woodstra, Chris. et al. 2005. All Music Guide to Classical Music. All Media Guide, LLC. p. 104. 

 What is the meaning of Beethoven’s ‘Für Elise’ – and who was Elise?

Other websites 
Für Elise - and other Beethoven resources (includes the free sheet music)

Compositions by Ludwig van Beethoven
Solo piano pieces
Teplice  (German name: Teplitz) is a city in Bohemia, the western area of the Czech Republic.  Teplice (pronounced in Czech: “Tep-li-tse”) is a famous spa town where, in earlier times, lots of famous people went for holidays to improve their health.  Goethe, Beethoven, Chopin, Franz Liszt and Richard Wagner all stayed there.

Teplice lies between Prague and Dresden in a mountain area called Krušné hory (Iron Mountains).  In the year 762 hot springs were found there.  The waters from these springs helped people who were ill to get better so it became a spa town.

Since 1990 many buildings have been restored.  The Krušnohorské divadlo (Krušnohorské theatre) is now being refurbished.  The North Bohemia Philharmonic Orchestra give concerts there in the open air.  There is a museum and many restaurants, wine bars and cafés.  In the winter the mountain slopes are good for skiing.

Other websites 
Official website 

Spa towns in the Czech Republic
Cities in the Czech Republic
Symphony No. 9 in D minor, Op. 125, is a symphony written by Ludwig van Beethoven. It is one of the most famous pieces of music ever written.

A symphony is a piece of music for orchestra. Beethoven wrote nine symphonies. This one, the last one he wrote, is very unusual because the last movement also has singing in it: there are four soloists (soprano, alto, tenor and bass) and a choir. This is why it is known as the “choral” symphony (“choral” means: “for choir”). It is a very long work, lasting more than an hour. This, too, was unusual.
This symphony has four movements. The first movement is in sonata form. The second and third movements come the other way round from the usual order: the second movement is the scherzo and the third movement is the slow movement. It is a theme and variations. The last movement sets the words of a poem by Friedrich Schiller, a famous poet who had only recently died. The poem was called Ode an die Freude (in English: Ode to Joy). The poem has a strong message to all mankind: it is about living in peace and harmony together. It was written at the time of the French Revolution when these ideas were becoming very important in Europe.
The main tune of the last movement (sung to the words: “Freude, schöne Götterfunken, Tochter aus Elysium”) is one of the best known tunes in the world. Many children like to play it on instruments because the first part of the tune only uses five notes (it can be played on C, D, E, F, G). When the tune comes the first time in the symphony it is played by the cellos and double basses.

The Ode to Joy was adopted as Europe's “National anthem” in 1972, with an official arrangement for orchestra written by Herbert von Karajan.
Beethoven had been interested in Schiller’s famous poem since he was young. In 1817 he started to write the first two movements of the symphony. In 1822 he decided to use Schiller’s poem in the symphony. Most of the rest of the symphony was written in 1823 and he finished it in 1824. It was first performed in May of that year. Beethoven conducted the performance. The story is told that he wondered why the audience were not applauding when it had finished. They were applauding, but Beethoven was deaf so he could not hear. Caroline Unger, the alto soloist, made him turn round, and he saw that people were applauding enthusiastically.

Symphony 09
Shatin Pui Ying College () is a Christian secondary school in Hong Kong. Its English name is simply said to be SPYC or PYC. It was started in 1978, and uses the money given by the Hong Kong government. There are 4 classes each for Forms 1 to 6 (as in 2019). The school icon is an eagle, which means courage and determination. Its location is at 9 Fung Shun Street, Wo Che Estate, Sha Tin District, Hong Kong.

What the school does
The school teaches its students for public examinations. The school motto is: Faith, Hope, Love" (「信、望、愛」). The school teaches the students other things to gain higher qualities of moral (德), intelligent (智), physical (體), social (群), art (美) and heart (靈).

School history
The father of the school is Rev Henry Noyes. In 1879, he built a school in Guangzhou, teaching Mathematics and Science. Later he built more schools in Taishan, Jiangmen and Hong Kong.
In 1978, someone built the 5th school which is Shatin Pui Ying College. Mr Wong Wai Wah was the Principal. In the first year, the school worked on the campus of Baptist Lui Ming Choi Secondary School at Lek Yuen Estate. In September 1979, the school could move into Wo Che Estate. The school library was opened since September 1982.

In order to make it possible for all the Form 3 students to study as Form 4 in the school, the school changed the class structure. The Student Union was set up in September 1995 and Parent-Teacher Association in 1996. In 1996, Principal Wong gave up working and the Vice Principal Ms Yau Oi Yuen started doing his work. The elite class system was deleted in September, 1996.

The library system was changed to use computer since September 2001. The new wing building of the school has been finished since July 2005. In the new wing, there are classrooms for higher forms classes, a new library, some special rooms and computer rooms.

Teaching languages
Teaching languages

English
Exchange students from Italy and Germany help the students learn English. The school has many English activities such as English Tutorial Class, English Drama Competition, Form 1 Bridging Programme, Lyrics-writing Course, English Immersion Speech Competition, Interviewing Tourists, English Phonetics Class, English Enhancement Course, Summer English Class, Overseas Immersion Course, Summer English Camp for senior form students, Summer English Day Camp for junior form students, Intra-school and Inter-school English Debate Competitions and English Musicals.
Chinese
The Chinese Language teachers write their own teaching units for the students. There are many Chinese activities such as Creative Writing Class, Chinese Week, Prose Writing Class, Reading Club, Modern Poetry Writing Class, Verse-speaking Gathering, Story Writing Class, and Seminar on Reading, Seminar on Modern Poetry, Intra-school and Inter-school Chinese Debate Competitions and Report and Comment on Chinese Words of Wisdom.

Putonghua
The school teaches Putonghua. There are many activities such as Putonghua Day, Tongue-Twisters, Putonghua Class, Singing Contest, Putonghua Broadcast and Putonghua Corner. Students in the school can learn more about the Chinese culture from the activities such as Workshop on Chinese clipart, Chinese Tea Tao and Chinese Culture and General Studies Competition.
Students in examinations
All Form 1 new students are Band 1 students. All of the Form 3 students can study as Form 4 in the school. Students have good results in public examinations. The average passing percentage for the HKCEE and HKALE is higher than 90%. The best student in HKCEE got 8As in 2004.

All Form 6 students in the school are from the Form 5 in the same school, except the exchange students from other countries. Most of the Form 7 students can study in the universities these years.

According to the government, the school teaches Chinese language, English language and Mathematics very well from 2000 to 2006.
The school gives the good students some awards, such as scholarships, Academic Awards, Flying Eagle Awards and Improvement Awards. The school gives money to some students to take part in some inter-school competition and courses in some universities such as the University of Hong Kong, the Chinese University of Hong Kong and the Hong Kong University of Science and Technology. There are some tutorial classes to improve junior students' skills in both English and Chinese languages and also Mathematics.

Special things

Reading activities
Reading Time is designed to help students having a good reading habit. Reading Days are held by the school library for all students to read or to take part in activities related to reading.

Information technology
There are many computer subjects in the school, such as Information Technology (IT) for Forms 1 to 3, Computer and Information Technology (CIT) for Forms 4 and 5, and Computer Applications (CA) for Forms 6 and 7.
Teaching art
The school has organised 3 musicals, The Comeback Kid, Soul for Sale and The Last Move. The songs inside are written by the students and past students. Every Form 1 student has to play at least 1 musical instrument. The Photography Club and the Audio-Visual Group teaches students many skills, such as film editing, image recording, lighting, backdrop setting and sound engineering.

Study about the world
The school invites some guest speakers to the school to give speeches. Students can know more about the political, social and economic issues in Hong Kong and around the world. The school lets the students to join some extracurricular activities such as "The Youth Summit", "Dinner with Outstanding Citizens" and "Hong Kong International Model United Nations". The school lets the students to join mainland and overseas cultural tours.
Student leaders
The students can take leadership-training courses and extracurricular activities, such as activities such as “Youth Leaders Auditorium 2005”, “The 6th Basic Certificate Course for Student Leaders”, “Outstanding Leadership Development Programme” and “Youth Think Tank Training Project”. There are Free Talks so that students can have better training in giving speeches.

Flying Eagle Award
This award is only for the students who have good learning habit, good examination results, good self-discipline, good responsibility, community skills and studies in school activities. There are 4 phases in this award. Students can get a Bronze Eagle Badge in Phase 1, a Silver Eagle Badge in Phase 2, a Gold Eagle Badge in Phase 3 and a cup in Phase 4.

Study about God
There are many activities to teach students about the Christian principles, such as Gospel Week, Gospel Camp Evangelical Team, Evangelical Broadcast, Bible Study Groups and Christian Fellowship.

School life
School life

School songs
There is a school song with Chinese lyrics. Its melody is the same as the song O Christmas Tree and there are two paragraphs. There is also a school hymn with English lyrics. There are three paragraphs in this school hymn.

School uniform
All boys in the school wear white shirts and green trousers, and all girls wear white dresses with green drawstrings as summer uniform. The boys wear grey trousers and the girls wear grey dresses with white socks as winter uniform. Both boys and girls wear green ties when wearing winter uniform.

When students have physical education lessons, they wear PE uniform. From 2000, students can wear PE uniform to school without changing at school. From 2001, the PE uniform has been changed into a new format that is grey and blue in colour. The PE T-shirts have 3 different colours, namely black, blue and red, with respect to the students’ house.
Classes
The class names are combined with one number and one English character, such as “6B”. After the New Secondary School program was out, the number of classes and students per class was changed. There are about 30 students in each class from Form 1 to Form 6. 1A and 1B are remedial classes whereas 1C to 1E perform better in exams. The classes are mixed when students go into Form 2 or Form 3.

All Form 3 students have to choose their subjects after finishing their year. After finishing  years of High Form study, students have to join the public exam, DSE (usually in April).

Houses
Each Form forms a House, with its own chairman and committee members elected by the students in the own Form. Each House has its own colour such as black, blue or red, just like the students’ PE uniform. The forms from the same colours form some cheering teams during the sports days.
Sports days and swimming gala
There are 2 sports days every year. The sports days take places on the Yuen Wo Road Sports Ground. Besides the various types of sports competitions, there are competitions among the cheering teams. The swimming gala is held every year with the Pui Ying Secondary School. It takes place on the Hong Kong Island or Sha Tin District alternatively every two years.

External competitions
Students in the school take parts in many external competitions in many fields such as music, sports, debates, writings, mathematics and other academic competitions. One of the most notable competitions is the Hang Lung Mathematics Award. The school’s HLMA team got an Honourable Mention in 2004 and a Special Commendation in 2006.

School organizations
Student union
The Student Union was established in November 1994. Its election activity is held in November every year. It helps the school setting new school rules and improves students’ lives. It organises activities such as blood donation days and ball game competitions.

Student Guidance Committee
It is formed by some teachers, social worker and psychologist to teach students how to have a true value.

Careers Guidance Committee
It helps students plan for their future by giving them information about different study opportunities and the world of work.

Disciplinary Committee
Some students may be naughty, so there are some prefects catching the naughty students.

School library
The school library has over 20000 books available to students. Every year there are about 100 school librarians. The book borrowing system was changed from man power only into computer system in 2001. The location of it was moved to the new wing building of the school in 2005. It organises Reading Day every year.
Information Technology Committee
It is made up of an IT technician and some teachers. They work together to provide the up-to-date information for the use of IT in teaching and learning. It trains the teachers and maintaining computer hardware and software. It also provide some advanced computers and facilities including digital video cameras and viewers.

Extra-curricular Activities Committee
There are 5 groups of extracurricular activities, including studying, services, entertainment, sports and Christian programme. They are divided into 40 clubs and activity groups.

Civic Education Committee
It teaches the students about civic education. There are many activities for the students to join..

Religious Education Committee
It is formed by a group of Christian teachers and Christ's Harvest Church to organize some special activities, Morning Assembly and Fellowship.
Pui Ying family
The school has good relationship with Guangzhou Pui Ying, Xiguan Pui Ying, Jiangmen Pui Ying, Taishan Pui Ying and Pui Ying Secondary School. In Canada, there is a Pui Ying Christian Services Society Pui Ying Alumni Associations can be found all over the world, such as in the USA, Canada, New Zealand, Australia, England, South Africa, Japan, Peru, Singapore, Thailand, Guangzhou, Taishan, Jiangmen and Taiwan.

Well known past students
 Joey Yung (容祖兒): A very popular female Canto pop singer and actress.
 Louise Ho (何璐怡): A female dubbing actress in TVB.
 Tsoi Chi Fu (蔡智夫): A writer of a computer reference book.

References

Other websites 
 The official website of Shatin Pui Ying College
 Secondary School Profile

Schools in Hong Kong
A heuristic is a practical way to solve a problem. It is better than chance, but does not always work. A person develops a heuristic by using intelligence, experience, and common sense. Trial and error is the simplest heuristic, but one of the weakest. Rule of thumb and 'educated guesses' are other names for simple heuristics. Since a heuristic is not certain to get a result, there are always exceptions.

Sometimes heuristics are rather vague: 'look before you leap' is a guide to behaviour, but 'think about the consequences' is a bit clearer. Sometimes a heuristic is a whole set of stages. When doctors examines a patient, they go through a whole set of tests and observations. They may not find out what is wrong, but they give themselves the best chance of succeeding. This is called a diagnosis.
In computer science, a 'heuristic' is a kind of algorithm. Algorithms are written to get a good solution to a problem. A heuristic algorithm might usually find pretty good solutions, but there is no guarantee or proof that the solutions are correct. The time it takes to run the algorithm is another consideration.

Background 
Heuristics is the art of finding an adequate solution to a problem, using limited knowledge and little time. More formally, heuristics are based on experience; they can speed up the search for a solution using simple rules. A complete search may take too long, or may be too difficult to do.

In more precise terms, heuristics are strategies using readily accessible, though loosely applicable, information to control problem solving in human beings and machines.
Heuristics can be used in some fields of science, but not in others: For economics, a solution that is one percent off is often acceptable; a telescope that has an error of one degree is probably unusable if aimed at a far-away object. The same telescope pointed to the window across the street will probably tolerate this error; missing by one degree will not have a big impact on a short distance.

Heuristics can be used to estimate an answer which is then made more clear by performing an exact solution at a very small scale, perhaps to save time, money or labor on a project - for example a heuristic guess as to how much weight a bridge is expected to carry can be used to determine whether the bridge should be made of wood, stone or steel, and appropriate quantities of the needed material can be purchased while the exact design of the bridge is being completed.
However, the use of heuristics in certain very technical fields may be damaging  computer science is one example. Programming a computer to perform more or less the desired actions may result in severe glitches. Therefore, computer tasks generally must be fairly exact. However, there are certain areas in which computers can calculate heuristic solutions safely  for example Google's search technology relies heavily on heuristics, producing "near-miss" matches to a search query when an exact match cannot be found. This enables a user to correct for any mistakes the search produces. Example: Searching for the name "Peter Smith" and unable to find that exact name, the search engine heuristically matches "Pete Smith" instead, and the person using the search engine must decide whether Pete and Peter are the same person.

Examples
Examples

Polya 
Here are some other commonly used heuristics, from Polya's 1945 book, How to Solve It:
 If you are having difficulty understanding a problem, try drawing a picture.
 If you can't find a solution, try assuming that you have a solution and seeing what you can derive from that ("working backward").
 If the problem is abstract, try examining a concrete example.
 Try solving a more general problem first: the "inventor's paradox": the more ambitious plan may have more chances of success.

Packing problem 

One example where heuristics are useful is a kind of packing problem. The problem consists of packing a number of items. There are rules that need to be respected. For example, each item has a value and a weight. The problem now is to get the most valuable items, with the least weight possible. Another instance is fitting a number of differently-sized items into a confined space, like the trunk of a car.
To get the perfect solution to the problem, all possibilities must be tried. This is often not a good option, as trying them takes a long time, and on average, half the possibilities must be tried until a solution is found. So what most people will do is to start with the biggest item, fit it in, and then try to arrange the other items around it. This will give a good solution, most of the time. There are cases however, where such a solution is very bad and another technique must be used.

Therefore, this is a heuristic solution.

References 

Problem solving
Mathematics
Computer science
In mathematics, a Mersenne number is a number that is one less than a power of two.

Mn = 2n − 1.

A Mersenne prime is a Mersenne number that is a prime number. This however, is not sufficient. Many mathematicians prefer the definition of a Mersenne number where exponent n has to be a prime number.

For example, 31 = 25 − 1, and 5 is a prime number, so 31 is a Mersenne number; and 31 is also a Mersenne prime because it is a prime number. But the Mersenne number 2047 = 211 − 1 is not a prime because it is divisible by 89 and 23. And 24 − 1 = 15 can be shown to be composite because 4 is not prime.

Throughout modern times, the largest known prime number has very often been a Mersenne prime. Most sources restrict the term Mersenne number to where n is prime, as all Mersenne primes must be of this form as seen below.
Mersenne primes have a close connection to perfect numbers, which are numbers equal to the sum of their proper divisors. Historically, the study of Mersenne primes was motivated by this connection; in the 4th century BC Euclid demonstrated that if M is a Mersenne prime then M(M+1)/2 is a perfect number. In the 18th century, Leonhard Euler proved that all even perfect numbers have this form. No odd perfect numbers are known, and it is suspected that none exist (If it exist, it would have to be greater than 101500).

It is currently unknown if there is an infinite number of Mersenne primes. Most mathematicians who have studied the question think there are an infinite number of Mersenne primes. Carl Pomerance, Samuel S. Wagstaff Jr. and Hendrik Lenstra developed a formula which they think should say about how many Mersenne primes there are under a given number.

The binary representation of 2n - 1 is n repetitions of the digit 1.

For example, 25 - 1 = 11111 in binary.
The first four Mersenne primes were known by the Ancient Greeks. They are 3, 7, and 127. The next, 8191, was discovered in 1456. Some people like trying to find big primes. Since there are tricks and algorithms to finding Mersenne primes quickly, the largest known primes are also Mersenne primes.

As of December 21, 2018, 51 Mersenne primes have been found. The largest known prime is a Mersenne prime, .

References

Classes of prime numbers
Insolation is derived  from  the  words "incoming solar radiation". Insolation is specifically applied to radiation which is arriving at earth’s atmosphere first and then earth's surface. The heat is derived from solar energy, normally called solar radiation. Insolation is the solar radiation that reaches the earth's surface. It is measured by the amount of solar energy received per square centimetre per minute. Similarly, solar energy received by the earth is called insolation. It is the amount of incoming solar radiation that is received over a unit area of the earth’s surface. Solar energy received over the planet’s surface varies according to season, latitude, transparency of the atmosphere, and aspect or ground slope.

Insolation affects temperature. The more the insolation, the higher the temperature.

In any given day, the strongest insolation is received at noon.
Factors influencing insolation 
The amount of insolation received on the earth’s surface is not uniform everywhere. It varies according to the place and time. When the tropical regions receive maximum annual insolation, it gradually decreases towards the poles. Insolation happens more in summers and less in winters. The major factors which influence the amount of insolation received are:

 Solar constant
 The angle of incidence of the sun’s rays
 Duration of the day
Earth Distance from Sun
 Transparency of the atmosphere
Solar Constant
At the top of the earth’s atmosphere, received insolation  is  expressed  as  the  solar  constant. It receives  at  the  top  of  the  atmospheric surface (thermopause) on  a perpendicular  plane  to the solar beam. The average insolation received at the thermopause i.e.1368Wm2(Watt per squaremetre)energy(solar constant) is in the form of short wave. Thus, it is termed as solar constant for that  mean  distance  from  the  sun. These solar constant  is  varying  over 1 Wm2 by  periodic disturbances and explosions in the solar surface basically related to sun spot. Sun spots are dark and cooler areas visible on the sun’s surface.The  recent  researches  have  shown  that  more and more  energy  is  released  when  the  sunpots  are  in  large  number.The  number  of  sunspots  also increases  or  decreases  on  a  regular  basis,  creating  a  cycle  of  11  years.

The angle of incidence
Since the earth is a geoid resembling a sphere, the sun’s rays strike the surface at different angles at different places. This depends on the latitude of the place.The higher the latitude, the less is the angle they make with the surface of the earth.
The area covered by the vertical rays is always less than the slant rays. If more area is covered, the energy gets distributed and the net energy received per unit area decreases. Moreover, the sun’s rays with small angle traverse more of the atmosphere than rays striking at a large angle.
Duration of The Day 
The length  of  the  day  determines  the  duration  of  sunlight  which  affects  the  amount  of solar radiation received by the earth’s surface. The longer  period  of sunshine,  greater  the  quantity  of solar  radiation will be  received by  a  portion  of  earth.For  example,  at  the  equator  the  length  of days  and  nights  is  12  hours in  all  the  months but the  tropics  of  Arctic  and  Antarctic sunshine duration varies between 0 and 24. On the autumn and springe quinoxes (September 23and March 21 respectively),the sun is overhead at the equatorat noon.The night and day all over the earth are equal on these days and maximum amount of insolation is received at the equator, and the amount of insolation decreasing towards  the  poles.It  is  caused  by  vertical  sunshine  at  equator  but  with  increasing  latitudes,  the rays  become  more  and  more  slanting.  Therefore,  poleward,  the  received  energy  keeps  on declining.
Earth's Distance from Sun
The earth is  revolving around  the  sun  in  an  elliptical  orbit, resulting  continuous  change  in the distance between sun and the earth on annual basis. It leads to seasonal variation in solar energy received by  the  earth.The  mean  distance  between  the  earth  and  sun  is  about  149,600,000 kilometers(92,900,000  miles).When  earth position is  farthest(152  million  km)  from sun  is known as ‘aphelion’ on  July  4.  It  is  perihelion(147  million  km)occurs on January  3  each  year which  is  the  closest  distance. During  aphelion the  northern  hemisphere  is  facing  the  sun  and therefore  receives  energy  about  7  percent  less  than  the  perihelion  (southern  hemisphere).
Transparency of the Atmosphere 
Atmosphere is not transparent for all the radiation coming from the sun because of different composition and layers.   It is  also  one  of  the  controlling  factors of  insolation to  reach  earth surface. The   atmosphere   is   composed   of   gases,   water   vapour   and particulate   matters.The atmosphere  is  a  mixture  of  gases,such  as nitrogen(N),  oxygen  (O2), Argon, carbon  dioxide, Neon  (Ne),  Helium  (He),  Methane  (CH4),  Krypton  (Kr),  Ozone  (O3),  Nitrous  oxide  (N2O), Hydrogen (H) and Xenon (Xe). The atmosphere also contains water vapour, water in the gaseous state.

The longer the duration of daylight, the more the insolation received per day.

Other websites 
 National Science Digital Library - Insolation 
 Yesterday‘s Australian Solar Radiation Map

Solar energy
Climate
The Settlers II is a real-time strategy (RTS) computer video game. It was released by Blue Byte Software in 1996.

1996 video games
Real-time strategy video games
Hugo Rafael Chávez Frías (IPA: ) (July 28, 1954 – March 5, 2013) was president of Venezuela from 1999 until his death in 2013. He was the leader of the "Bolivarian Revolution" and promoted his vision of democratic socialism, Latin American integration, and anti-imperialism. Chávez was also an ardent critic of neoliberal globalization and U.S. foreign policy.

Career
Chávez was a career military officer. He founded the left-wing Fifth Republic Movement after a failed coup d'état against former President Carlos Andrés Pérez. Chávez was elected to serve as president in 1998. This was mainly because he promised to help the poor majority of Venezuelan people. He was re-elected in 2000, and 2006.
He started a movement called Bolivarian Missions. Its goal is to fight disease, illiteracy, malnutrition, poverty, and other social problems. Abroad, Chávez is known for supporting alternative models of economic development. He also spoke in favor of a collaboration of poor nations, especially those in Latin America. On September 20, 2006, Chávez made a speech to the UN General Assembly. Chávez said that U.S. President George W. Bush is "The devil came here yesterday, and it smells of sulfur still today".

Chávez's reforms have caused controversy, both inside Venezuela, and outside the country. Some people criticized the reforms, others supported them. Those people who support the reforms say that he has given more power to the poor, and that he has stimulated economic growth. Those who argue against the reforms say that he is an autocrat who has mismanaged the economy.
Some governments, especially the government of the United States saw Chávez as a threat to global oil prices, as well as to regional stability. Others sympathize with his ideology or welcome his bilateral trade and reciprocal aid agreements.

Awards
In 2005 and 2006 he was named one of Time magazine's 100 most influential people. Chavez has received many prizes: He has received honorary doctorates from the University of Beijing, the university of Rio de Janeiro, the university of Santo Domingo, and Kyung Hee University in South Korea.
Belief
Chávez said he was a Roman Catholic. Much like his predecessor Simon Bólivar, Chávez tolerated elements of belief systems,popular in Venezuela, such as the María Lionza cult and Sanería. These movements mix Roman Catholic belief with other elements, such as those of Voodoo and Shamanism. Chavez also put emphasis on the social ideas of the Catholic church, and remained in the background when it came to discussing controversial ideas. His ideas caused controversy with some clerics of the Catholic church, and some evangelical movements. While he was na pilgrimage, cardinal Rosalio Lara said that those that did not have the same ideas as the people in power were persecuted, and that Chavez' way of running the country was undemocratic.
Health
He had an operation on his pelvis to remove his colorectal cancer. In January 2013, his cancer worsened and was put on life support. Chávez put his daughter in charge whether he should live or die. He was treated for the disease in Cuba and in Venezuela. On February 27, 2013 rumors said that his daughter stopped the life support on February 23. Later on February 28, the Vice President said that Chávez was fighting for his life. Chávez died of colorectal cancer on March 5, 2013.

Death

On March 5, 2013 Vice President Nicolás Maduro announced on state television that Chávez died in Caracas, Venezuela at 16:25 VET (2055 UTC). The cause of his death was a heart attack caused by colorectal cancer and respiratory failure. He battled cancer since June 2011. He is survived by his three daughters and one son. Leaders from the world shared reactions about Chávez's death.

References

Other websites
Other websites

 Hugo Chávez en "La Patria Grande de Caracas"
 PBS Frontline Documentary: The Hugo Chávez Show
 Chavez: Inside the Coup: The Revolution Will Not Be Televised
 The Guardian: The Rise and Rule of 'Hurricane Hugo' audio slide show
 Democracy Now! September 16, 2005 Interview: Part I  and Part II  with Hugo Chávez, in New York City
 ABC News Video, April 27, 2007: Barbara Walters interviews Hugo Chávez
 Interview with Hugo Chávez about the American threat October 2009
 NPR Audio Report, February 18, 2008: The Politics of Venezuela's Hugo Chávez

Deaths from colorectal cancer
Deaths from respiratory failure
Deaths from myocardial infarction
Cancer deaths in Venezuela
Presidents of Venezuela
Former dictators
Democratic socialists
Venezuelan Roman Catholics
1954 births
2013 deaths
Granule is a generic term used for a small particle or grain.  The generic term is used in a lot of contexts.

 Granule (solar physics), visible structures in the photosphere of the Sun arising from activity in the Sun's convective zone
 Granule (cell biology), any of several submicroscopic structures, some with explicable origins, others noted only as cell type-specific features of unknown function
 "Azurophil granule", a structure characteristic of the azurophil eukaryotic cell type
 "Chromaffin granule", a structure characteristic of the chromophil eukaryotic cell type
 Martian spherules, spherical granules of material found on the surface of the planet Mars
 A specified particle size of 2–4 millimetres (-1– -2 on the φ scale)
In cell biology, a granule can be any structure barely visible by light microscopy. The term is most often used to describe a secretory vesicle.

Leukocytes 
A group of leukocytes called granulocytes contain granules and play an important role in the immune system. The granules of certain cells, such as Natural killer cells, contain components which can lead to the lysis of neighboring cells.

Platelets 
The granules of platelets are classified as dense granules and alpha granules.

Cell biology
The cytosol (also known as intracellular fluid (ICF) or cytoplasmic matrix, or groundplasm) is the internal fluid of the cell, and a part of cell metabolism occurs here.

Proteins within the cytosol play an important role in signal transduction pathways and glycolysis.

Cytosol mostly consists of water, dissolved ions, small molecules, and large water-soluble molecules (such as protein). It contains about 20% to 30% protein.

Normal human cytosolic pH is (roughly) 7.0 (i.e. neutral), whereas the pH of the extracellular fluid is 7.4.

The texture of cytosol being described as granular can be attributed to the fact that in order to study the texture, an electron microsope must be used, which requires a process of dehydration prior to study.

References
Life: the science of biology. Purves, Sadava, Orians, Heller. Sunderland, MA. Sinauer Associates, Inc. 2004.  (ILM USA)

Metabolism
Joan Jett (born February 1958) is an American singer and guitarist. She is best known for her number one single "I Love Rock n Roll". Jett has a punkish, tomboy appearance and is a Democrat.

In 2015, she was inducted into the Rock and Roll Hall of Fame.

References 

1960 births
Living people
American rock guitarists
American rock singers
Singers from Pennsylvania
Musicians from Pennsylvania
American punk musicians
Rock and Roll Hall of Fame inductees
For the toy, see marbles
Marble is a metamorphic rock that developed from limestone. Most of the material is calcite (a crystalline form of calcium carbonate, CaCO3) and dolomite. It is often used for sculpture, as a building material, and for many other purposes.

The word 'marble' is also used for other stones that can be polished well and for ball shaped objects used for child games. 

'Faux marble' is a wall painting technique that imitates the color patterns of real marble (not to be confused with paper marbling). Marble dust can be combined with cement or synthetic resins to make reconstituted or cultured marble.
Marble has been used in construction for thousands of years. It was widely used by Greek and Roman sculptors and architects. Places named after the stone include Marble Arch, London; the Sea of Marmara; India's Marble Rocks; and the towns of Marble, Minnesota; Marble, Colorado; and Marble Hill, Manhattan, New York. The Elgin Marbles are marble sculptures from the Parthenon that are on display in the British Museum.  They were brought to Britain by the Earl of Elgin.

Construction marble 

In the construction trade, the term "marble" is used for any massive, crystalline calcitic rock (and some non-calcitic rocks) useful as building stone.

Examples 
Purbeck marble is a fossiliferous limestone found in the Isle of Purbeck, a peninsula in south-east Dorset, England. It has been quarried since at least Roman times as a decorative building stone. The industry is no longer active.