Rod (optics)

"Rods" (sometimes known as "skyfish", "air rods", or "solar entities") is a term used in cryptozoology, ufology, and outdoor photography to refer to elongated artifacts in the form of light-rods produced by cameras. Videos of rod-shaped objects moving quickly through the air were claimed by some ufologists and cryptozoologists to be alien life forms, "extradimensional" creatures, or very small UFOs. Subsequent experiments showed that these rods appear in film because of an optical illusion/collusion (especially in interlaced video recording), and are typically traces of a flying insect's wingbeats.

Optical analysis

Various paranormal interpretations appeared in the popular culture, and one of the more outspoken proponents of rods as alien life forms is Jose Escamilla, who claims to have been the first to film them on March 19, 1994 at Roswell, New Mexico, while attempting to film a UFO. Since then, Escamilla has made additional videos and embarked on lecture tours to promote his claims.

Ptolemy

Claudius Ptolemy (/ˈtɒləmi/; Greek: Κλαύδιος Πτολεμαῖος, Klaúdios Ptolemaîos, [kláwdios ptolɛmɛ́ːos]; Latin: Claudius Ptolemaeus; c. AD 100 – c. 170) was a Greco-Egyptian writer, known as a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in the city of Alexandria in the Roman province of Egypt, wrote in Koine Greek, and held Roman citizenship. Beyond that, few reliable details of his life are known. His birthplace has been given as Ptolemais Hermiou in the Thebaid in an uncorroborated statement by the 14th-century astronomer Theodore Meliteniotes. This is a very late attestation, however, and there is no other reason to suppose that he ever lived anywhere else than Alexandria, where he died around AD 168.

Ptolemy was the author of several scientific treatises, three of which were of continuing importance to later Byzantine, Islamic and European science. The first is the astronomical treatise now known as the Almagest, although it was originally entitled the "Mathematical Treatise" (Μαθηματικὴ Σύνταξις, Mathēmatikē Syntaxis) and then known as the "Great Treatise" (Ἡ Μεγάλη Σύνταξις, Ē Megálē Syntaxis). The second is the Geography, which is a thorough discussion of the geographic knowledge of the Greco-Roman world. This manuscript was used by Christopher Columbus as the map for his westward-bound path to Asia, in which he discovered the hitherto unknown lands of the Americas. The third is the astrological treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day. This is sometimes known as the Apotelesmatika (Ἀποτελεσματικά) but more commonly known as the Tetrabiblos from the Greek (Τετράβιβλος) meaning "Four Books" or by the Latin Quadripartitum.

Dioptrique

La dioptrique (in English Dioptrique, Optics, or Dioptrics), is a short treatise published in 1637 included in one of the Essays written with Discourse on the Method by Rene Descartes. In this essay Descartes uses various models to understand the properties of light. This essay is known as Descartes' greatest contribution to optics, as it is the first publication of the Law of Refraction.

First Discourse: On Light

The first discourse captures Descartes' theories on the nature of light. In the first model, he compares light to a stick that allows a blind person to discern his environment through touch. Descartes says:

Descartes' second model on light uses his theory of the elements to demonstrate the rectilinear transmission of light as well as the movement of light through solid objects. He uses a metaphor of wine flowing through a vat of grapes, then exiting through a hole at the bottom of the vat.

Second Discourse: On Refraction

Descartes uses a tennis ball to create a proof for the laws of reflection and refraction in his third model. This was important because he was using real-world objects (in this case, a tennis ball) to construct mathematical theory. Descartes' third model creates a mathematical equation for the Law of Refraction, characterized by the angle of incidence equalling the angle of refraction. In today's notation, the law of refraction states,

Al-Kindi

Abu Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (Arabic: أبو يوسف يعقوب بن إسحاق الصبّاح الكندي‎, Latin: Alkindus) (c. 801–873 AD), known as "the Philosopher of the Arabs", was a Muslim Arab philosopher, polymath, mathematician, physician and musician. Al-Kindi was the first of the Muslim peripatetic philosophers, and is unanimously hailed as the "father of Islamic or Arabic philosophy" for his synthesis, adaptation and promotion of Greek and Hellenistic philosophy in the Muslim world.

Al-Kindi was a descendant of the Kinda tribe. He was born in Basra and educated in Baghdad. Al-Kindi became a prominent figure in the House of Wisdom, and a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language. This contact with "the philosophy of the ancients" (as Greek philosophy was often referred to by Muslim scholars) had a profound effect on his intellectual development, and led him to write hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics, logic and psychology, to medicine, pharmacology, mathematics, astronomy, astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, meteorology and earthquakes.

Rod

Rod, Ród, Rőd, Rød, Röd, ROD, or R.O.D. may refer to:

Devices

Media

Rod cell

Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than the other type of visual photoreceptor, cone cells. Rods are concentrated at the outer edges of the retina and are used in peripheral vision. On average, there are approximately 90 million rod cells in the human retina. More sensitive than cone cells, rod cells are almost entirely responsible for night vision. However, because they have only one type of light-sensitive pigment, rather than the three types that human cone cells have, rods have little, if any, role in color vision (which is why colors are much less apparent in darkness).

Structure

Rods are a little longer and leaner than cones but have the same structural basis. The opsin or pigment is on the outer side, lying on the Retinal pigment epithelium, completing the cell's homeostasis. This epithelium end contains many stacked disks. Rods have a high area for visual pigment and thus substantial efficiency of light absorption.

Corporal punishment

Corporal punishment or physical punishment is punishment intended to cause physical pain on a person.

Common methods include spanking, paddling, caning and also bastinado. It can occur on minors but also on other individuals subjected to a right of corporal punishment such as prisoners in several countries or slaves in former times.

Official punishment for crime by inflicting pain or injury, including flogging, branding and even mutilation, was practised in most civilisations since ancient times. However, with the growth of humanitarian ideals since the Enlightenment, such punishments were increasingly viewed as inhumane. By the late 20th century, corporal punishment had been eliminated from the legal systems of most developed countries.

The legality in the 21st century of corporal punishment in various settings differs by jurisdiction. Internationally, the late 20th century and early 21st century saw the application of human rights law to the question of corporal punishment in a number of contexts: