Binaural beats

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Binaural beats
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To experience the binaural beats perception, it is best to listen to this file with headphones on moderate to weak volume – the sound should be easily heard, but not loud. Note that the sound appears to pulsate only when heard through both earphones.
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Binaural Beats Base tone 200 Hz, beat frequency from 7 Hz to 12,9 Hz
Binaural beats, or binaural tones, are auditory processing artifacts, or apparent sounds, caused by specific physical stimuli. This effect was discovered in 1839 by Heinrich Wilhelm Dove and earned greater public awareness in the late 20th century based on claims coming from the alternative medicine community that binaural beats could help induce relaxation, meditation, creativity and other desirable mental states. The effect on the brainwaves depends on the difference in frequencies of each tone: for example, if 300 Hz was played in one ear and 310 in the other, then the binaural beat would have a frequency of 10 Hz.[1][2]
The brain produces a phenomenon resulting in low-frequency pulsations in the amplitude and sound localization of a perceived sound when two tones at slightly different frequencies are presented separately, one to each of a subject's ears, using stereo headphones. A beating tone will be perceived, as if the two tones mixed naturally, out of the brain. The frequencies of the tones must be below 1,000hertz for the beating to be noticeable.[3] The difference between the two frequencies must be small (less than or equal to 30 Hz) for the effect to occur; otherwise, the two tones will be heard separately, and no beat will be perceived.
Binaural beats are of interest to neurophysiologists investigating the sense of hearing.[4][5][6][7]
Binaural beats reportedly influence the brain in more subtle ways through the entrainment of brainwaves[3][8][9] and provide other health benefits such as control over pain.[10][11]

Acoustical background[edit]

Interaural time differences (ITD) of binaural beats
For sound localization, the human auditory system analyses interaural time differences between both ears inside small frequency ranges, called critical bands. For frequencies below 1000 to 1500 Hz interaural time differences are evaluated from interaural phase differences between both ear signals.[12] The perceived sound is also evaluated from the analysis of both ear signals.
If different pure tones (sinusoidal signals with different frequencies) are presented to each ear, there will be time-dependent phase and time differences between both ears (see figure). The perceived sound depends on the frequency difference between both ear signals:
  • If the frequency difference between the ear signals is lower than a few hertz, the auditory system can follow the changes in the interaural time differences. As a result, an auditory event is perceived, which is moving through the head. The perceived direction corresponds to the instantaneous interaural time difference.
  • For slightly bigger frequency differences between the ear signals (more than 10 Hz), the auditory system can no longer follow the changes in the interaural parameters. A diffuse auditory event appears. The sound corresponds to an overlay of both ear signals, which means amplitude and loudness are changing rapidly (see figure in the chapter above).
  • For frequency differences between the ear signals of above 30 Hz, the cocktail party effect begins to work, and the auditory system is able to analyze the presented ear signals in terms of two different sound sources at two different locations, and two distinct signals are perceived.
Binaural beats can also be experienced without headphones; they appear when playing two different pure tones through loudspeakers. The sound perceived is quite similar: with auditory events that move through the room, at low-frequency differences, and diffuse sound at slightly bigger frequency differences. At bigger frequency differences, apparent localized sound sources appear.[13] However, it is more effective to use headphones than loudspeakers.

Timeline of the Hebrew prophets

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This is a timeline of the development of prophecy among the Jews in Judaism. All dates are given according to the Common Era, not the Hebrew calendar.
See also Jewish history which includes links to individual country histories.

the Exodus[edit]

c. 1312 BC(?*)[citation needed]
the Exodus from Egypt (Moses)

the Land of Israel[edit]

c. 1250 BC[citation needed]
Joshua leads the people
c. 1150 BC–c. 1025 BC[citation needed]
Biblical Judges lead the people

During the Kingdom of Israel and Judah[edit]

c. 1025 BC–c. 1007 BC[citation needed]
King Saul, prophecy of Samuel
c. 1010 BC–c. 970 BC[citation needed]
King David, prophecy of Nathan
c. 1001 BCE–c. 931 BC[citation needed]
King Solomon
c. 931 BC–c. 913 BC[citation needed]
King Rehoboam of Judah
c. 931 BC–c. 910 BC[citation needed]
King Jeroboam of Israel, prophecy of Ahijah
c. 911 BC–c. 910 BC[citation needed]
King Asa of Judah
prophecies of JehuElijahMicaiah, and Elisha
c. 837 BC–c. 800 BC[citation needed]
King Joash of Judah
prophecy of Joel
c. 796 BC–c. 768 BC[citation needed]
King Joash of Judah
prophecy of AmosHosea
c. 767 BC–c. 754 BC[citation needed]
King Uzziah of Judah
prophecy of Micah
c. 740 BC–c. 700 BC[citation needed]
prophesy of Isaiah
c. 740 BC–c. 722 BC[citation needed]
Kingdom of Israel falls to Neo-Assyrian Empire
c. 715 BC–c. 687 BC[citation needed]
King Hezekiah of Judah
prophecy of Nahum

During Exile[edit]

c. 597 BC–c. 520 BC[citation needed]
prophecy of Jonah[1] during the time of Babylonian captivity, though dating of the book ranges from the 6th to the late 3rd century BC.
At Judea
prophecy of ZephaniahJeremiahHabakuk
At Babylon
prophecy of Ezekiel

Post Exile[edit]

c. 520 BC–c. 411 BC[citation needed]
prophecy of HaggiahZechariah
Return to the land under Persian rule, and writings of Ezra-Nehemiah
Story of Esther
c. 433 BC [?][citation needed]
prophecy of Malachi during the times of the Persian Empire
c. 160 BC
"prophecy" of Daniel during the time of the Seleucid dynasty. Note that in Jewish scripture, Daniel is not considered a prophet and is not included among the prophetic books.

Zaidiyya or Zaidism

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Zaidiyya or Zaidism (Arabic: الزيدية az-zaydiyya, adjective form Zaidi or Zaydi) is an early sect which emerged out of Shi'a Islam named after Zayd ibn ʻAlī, the grandson of Husayn ibn ʻAlī. Followers of the Zaydi Islamic jurisprudence are called Zaydi Shi'a and make up about 35% of Muslims in Yemen.[1] The Zaydi Shi'a have a unique approach within Shi'a Islamic thought. Its adherents are also known as Fivers.

Zaidi Imāms[edit]

The first three Zaidi imams were Ali ibn Abu TalibHasan ibn Ali, and Husayn ibn Ali.[2] The Zaidis believe that these three, along with theIslamic Prophet Muhammad and Fatima, are part of the Ahl al-Kisa. After these three imams, the Zaidis have a number of imams beginning with Zayd ibn Ali[2] followed by his son Yahya ibn Zayd.[3] They believe any descendant of Hasan or Husayn can be an imam[4]if he exhibits two attributes; "excel[ing] in knowledge" and "call[ing] others to fight against oppressors".[2] If an individual possesses one of these two attributes, he can be considered an imam of a lesser degree.[2]
For example, Zaydis consider the fourth, fifth, and sixth Twelver imams, Zain al-AbidinMuhammad al-Baqir and Ja'far al-Sadiq, imams in this lesser sense due to their high levels of knowledge, but do not consider them imams in the absolute sense because they did not revolt against the oppressors of their time.[2] An example of an imam from the lineage of imam Hassan is Muhammad al-Nafs al-Zakiyya.[2]
Zaydi (early period) imams as listed in Al-Masaabeeh fee As-Seerah by imam Ahmad bin Ibrahim after Ali are:
  1. Al-Hasan bin Ali bin Abi Talib
  2. Al-Husayn bin Ali bin Abi Talib
  3. - Al-Hasan al-Mu'thannā bin Al-Hassan al-mujtaba bin Ali al Murtaza bin Abi Talib
  4. Zayd bin Ali Zayn al-'Ābidin bin Al-Husayn
  5. - Yahya bin Zayd bin Ali Zayn al-'Ābidin bin Al-Husayn
  6. Muhammad bin Abdillah al-Kāmil bin Al-Hasan al-Mu'thannā bin Al-Hasan An-Nafs-Az-Zakiyyah
  7. - Ibrahim bin Abdillah al-Kāmil bin Al-Hasan al-Mu'thannā bin Al-Hassan al mujtaba bin Ali al Murtaza bin Abi Talib
  8. - Abdullah bin Muhammad bin Abdillah al-Kāmil bin Al-Hasan al-Mu'thannā bin Al-Hassan al-mujtaba bin Ali bin Abi Talib
  9. - Al-Hasan bin Ibrahim bin Abdillah al-Kāmil bin Al-Hasan al-Mu'thannā bin Al-Hassan al-mujtaba bin Ali bin Abi Talib
  10. - Al-Husayn bin Ali bin Al-Hasan bin Al-Hasan al-Mu'thannā bin Al-Hassan al-mujtaba bin Ali bin Abi Talib
  11. - Isa bin Zayd bin Ali bin Al-Husayn
  12. - Yahya bin Abdillah al-Kāmil bin Al-Hasan bin Al-Hasan bin Ali bin Abi Talib
  13. Idris bin Abdillah al-Kāmil bin Al-Hasan bin Al-Hasan bin Ali bin Abi Talib
  14. - Muhammad bin Ibrahim bin Isma'il bin Ibrahim bin Al-Hasan bin Al-Hasan bin Ali bin Abi Talib
  15. - Muhammad bin Muhammad bin Zayd bin Ali bin Al-Husayn
  16. - Muhammad bin Sulayman bin Dawud bin Al-Hasan bin Al-Hasan bin Ali bin Abi Talib
  17. - Al-Qasim bin Ibrahim bin Isma'il bin Ibrahim bin Al-Hasan bin Al-Hasan bin Ali bin Abi Talib
  18. Yahya bin Al-Husayn bin Al-Qasim Al-Hadi
  19. Abul Qasim Muhammad bin Yahya bin Al-Husayn
  20. Ahmad bin Yahya bin Al-Husayn
  21. - Al-Hasan bin Ali An-Nasir

Summary[edit]

Zaydis, the oldest branch of the Shia and the largest group amongst the Shia before the Safavid Dynasty in the sixteenth century and currently the second largest group, are the closest to the Sunnis and do not believe in the infallibility of Imāms after Husayn. Zaydis believe that on the last hour of Zayd ibn Ali, he was betrayed by the people in Kufa who said to him: "May God have mercy on you! What do you have to say on the matter of Abu Bakr and Umar ibn al-Khattab?" Zayd ibn Ali said, "I have not heard anyone in my family renouncing them both nor saying anything but good about them...when they were entrusted with government they behaved justly with the people and acted according to the Qur'an and the Sunnah."[5]

Law[edit]

In matters of Islamic jurisprudence, the Zaydis follow Zayd ibn ’Ali's teachings which are documented in his book Majmu’ al-Fiqh (Arabic:مجموع الفِقه‎). Zaydi fiqh is similar to the Hanafi school of Sunni Islamic jurisprudence.[6] Abu Hanifa, a Sunni madhab founder, was favorable and even donated towards the Zaydi cause.[7]

Theology[edit]

In matters of theology, the Zaydis are close to the Mu'tazili school, though they are not Mu'tazilite. There are a few issues between both schools, most notably the Zaydi doctrine of the Imamate, which is rejected by the Mu'tazilites. Of the Shi'a, Zaydis are most similar to Sunnis[8] since Zaydism shares similar doctrines and jurisprudential opinions with Sunni scholars.[9]

Beliefs[edit]

Like all Muslims, the Zaydi Shi'a affirm the fundamental tenet of Islam known as the Shahadaor testament of faith  – "There is no deity (worthy of worship) but ALLAH and Muhammad is His Messenger." Traditionally, the Zaydi believe that Muslims who commit major sins without remorse should not be considered Muslims nor be considered kafirs but rather be categorized in neither group.
In the context of the Shi'a Muslim belief in spiritual leadership or Imamate, Zaydis believe that the leader of the Ummah or Muslim community must be Fatimids: descendants of Muhammad through his only surviving daughter Fatimah, whose sons were Hasan ibn ʻAlīand Husayn ibn ʻAlī. These Shi'a called themselves Zaydi so they could differentiate themselves from other Shi'is who refused to take up arms with Zayd ibn Ali and the later Zaydi Imams.
Zaydis believe Zayd ibn Ali was the rightful successor to the Imamate because he led a rebellion against the Umayyad Caliphate, who he believed were tyrannical and corrupt.Muhammad al-Baqir did not engage in political action and the followers of Zayd believed that a true Imām must fight against corrupt rulers.[10] The renowned Muslim jurist Abū Ḥanīfa who is credited for the Hanafi school of Sunni Islam, delivered a fatwā or legal statement in favour of Zayd in his rebellion against the Umayyad ruler. He also urged people in secret to join the uprising and delivered funds to Zayd.[11]
In contrast to other Shi'a Muslims, the Zaydis do not believe in the infallibility of Imāms after Husayn. Zaydis also do not believe that the Imāmate must pass from father to son but believe it can be held by any descendant from either Hasan ibn ʻAlī and Husayn ibn ʻAlī. Orthodox Shi'is do not necessarily believe in Imamate passing from father to son either, as can be seen from the transition of Imamate from the second Imam, Hasan ibn Alī, after his death, to his brother, Husayn ibn Alī.
Zaydis, like Sunni Muslims, further reject the notion of Occultation (ghayba) of the Imām. Like the Nizaris, they believe in a living visible Imām.[12]
The Twelver Imam Ali al-Ridha narrated how his grandfather Ja'far al-Sadiq also supported Zayd ibn Ali's struggle:
Jafar al-Sadiq's love for Zayd ibn Ali was so immense, he broke down and cried upon reading the letter informing him of his death and proclaimed:

History[edit]

Status of Caliphs and the Sahaba[edit]