Saturday, April 13, 2013

Analemmas

http://en.wikipedia.org/wiki/Insolation 
http://en.wikipedia.org/wiki/Analemma
http://fr.wikipedia.org/wiki/Lever_de_soleil

Horaire -Causes astronomiques

Du fait de l'inclinaison de l'axe terrestre et de l'excentricité de son orbite, l'heure de lever du Soleil varie tout au long de l'année, et dans des proportions différentes suivant la latitude du lieu, des conséquences de l'équation du temps du lieu d'observation, ainsi que de la durée totale du jour.
On considère généralement que le lever de soleil se produit lorsque le bord supérieur de l'étoile apparaît au-dessus de l'horizon. En revanche, les éphémérides donnent le moment où le centre du Soleil le franchit, ce qui se produit en général une à deux minutes après. L'heure de lever de soleil est également modifiée par l'altitude.
Latitude
Près de l'équateur, les variations de l'heure de lever du Soleil reproduisent celles de l'équation du temps en oscillant de plusieurs minutes autour d'une valeur moyenne, mais deux fois par an : l'heure du lever décroît de mi-février à mi-mai, puis croît jusqu'à la fin juillet avant de décroître jusqu'au début novembre et croître jusqu'à la mi-février de l'année suivante. Le Soleil se lève au plus tôt vers le début novembre et le lever le plus tardif se produit vers le 10 février, mais il n'y a moins d'une demi-heure d'écart entre ces deux horaires. Vers de latitude, le Soleil se lève le plus tôt deux fois dans l'année, vers la fin mai et la fin octobre. Au-delà, l'horaire du lever tend à n'osciller qu'une seule fois dans l'année pour globalement devenir plus tardive en été et en automne et inversement en hiver et au printemps. Vers 14° de latitude, il existe une période (septembre dans l'hémisphère nord, avril dans l'hémisphère sud) où le Soleil se lève à peu près à la même heure tous les jours1.
Aux latitudes moyennes, le Soleil se lève de plus en plus tôt en hiver et au printemps. Les variations de l'heure de lever ralentissent ensuite progressivement et le Soleil finit par se lever de plus en plus tard tout au long de l'été et du printemps. Cependant, les levers les plus tardifs et les plus tôt n'ont pas lieu aux solstices : dans l'hémisphère nord, le Soleil se lève au plus tard début janvier et au plus tôt vers la mi-juin. La différence entre les deux horaires atteint plusieurs heures.
Aux latitudes élevées, au-delà du cercle polaire arctique et antarctique, il existe une période où le Soleil reste constamment au-dessus de l'horizon et une autre où il est situé en dessous de l'horizon. Dans les deux cas, le lever de soleil ne se produit plus.

Orientation

Du fait de l'inclinaison de l'axe de la Terre, dans l'hémisphère nord, les levers de soleil se produisent toujours dans le quadrant nord-est entre l'équinoxe de mars et celle de septembre, et dans le quadrant sud-est entre l'équinoxe de septembre et celle de mars. C'est le contraire dans l'hémisphère sud.
L'azimuth du Soleil au lever n'est réellement égal à l'est qu'aux équinoxes ; pendant le reste de l'année, il évolue au sud et au nord de cette position.

Sunday, October 28, 2012

Wednesday, August 22, 2012

Bellum se ipsum alet

La guerra se nutre a sí misma
Der Krieg ernährt den Krieg
The war will feed itself
--Cato Marcus Porcius ("the Elder", 234–149 BC)

La Primera Guerra Mundial en Color
Hasta la actualidad, la Primera Guerra Mundial siempre se habia visto como algo que sucedió en blanco y negro, pero no era real.
Usando imágenes de archivo inéditas de Rusia, Alemania, Francia, Italia, Estados Unidos y el Museo Imperial de Guerra británico, esta serie se ha coloreado usando la última tecnologia por ordenador, devolviendo por primera vez el color a la Primera Guerra Mundial, tal y como la experimentaron quienes lucharon y quienes sobrevivieron. Se necesitaron 5 meses y 490 tecnicos para colorear los archivos de blanco y negro, prácticamente inéditos.
Fue durante la Primera Guerra Mundial que se desarrolló el avión de combate, se introdujo el gas venenoso, se inventaron el tanque y los lanzallamas, y se extendió el uso de la ametralladora y de la artilleria pesada, lo que produjo una destrucción masiva.
Esta serie aporta una perspectiva única de los sucesos que ocurrieron entre 1914 y 1918 y que contempló cómo 65 millones de hombres tomaron las armas para luchar el uno contra el otro, Ilevando el mundo al caos. Esta es la guia definitiva de la Primera Guerra Mundial como nunca se ha visto.
  1. Miniatura1 Catastrofe 47:32
La guerra civil española

Con la proclamación de la Segunda República, el 14 de abril de 1931, se abría en España un período democrático cuyos principios quedaban recogidos en la nueva constitución republicana. Contando con un amplio apoyo popular, la República afrontó un ambicioso programa de reformas (el ejército, la educación, el campo, las autonomías) que encontró fuertes resistencias entre los militares, la Iglesia y la oligarquía. La victoria electoral del Frente Popular en febrero de 1936 dio inicio a un período de radicalización política y agitación social. En este clima se produjo, el 18 de julio de 1936, el levantamiento militar que los sublevados llamarían después Alzamiento Nacional. Empezaba la Guerra Civil Española.
Durante la Guerra Civil Española la República vivió bajo una crisis permanente, en la que las luchas intestinas no dejaron nunca de estar presentes. El enfrentamiento de los revolucionarios anarcosindicalistas y del POUM con los comunistas y las fuerzas republicanas debilitaron el gobierno constitucional. Mientras que los comunistas postergaban el inicio de una posible revolución al triunfo en la guerra, los anarquistas intentaban compaginar guerra y revolución. Al final, el curso de la guerra, que dio la victoria a los sublevados, frustró las expectativas de unos y otros.

La Guerra Civil Española : Episodio 3 - La Guerra De Los Idealistas La Guerra Civil Española : Episodio 3

La Guerra Civil Española : Episodio 5
The Second World War in Colour

"The Second World War in Colour" or simply "Colour of War" as it is released here in Belgium is a very good documentary about WWII and how it affected life around the world between 1940 and 1945. The entire documentary is a collection of authentic images, all in colour, of which a lot have been previously unreleased. Some images can be quite shocking at times and no doubt leave you with a bitter impression on how horrible war can be. The commentator also reads out a lot of letters or diary fragments from people who lived or died during World War II. Knowing this, you might think that the documentary in a whole would loose coherence but it's quite the opposite because even though "Colour of War" is mainly a collection of authentic images and letters it felt like everything fitted together very well.
About all the major events which happened during the period 1936-1945 are included. For example the German invansion in Poland and France, the bombing of London, Pearl Harbor, the confrontation between the American fleet and the German U-boats, Stalingrad, the American invasions of the Japanese islands, D-day, the Holocaust, Japanese Kamikazes, Hiroshima, ... it's all there.


World War II in HD
WWII in HD (known as World War II: Lost Films in the UK) is a 10-part American documentary television miniseries that originally aired from November 15 to November 19, 2009 on the History Channel. The program focuses on the firsthand experiences of twelve American service members during World War II, including an Army nurse, a member of the Tuskegee Airmen, a second generation Japanese American and prisoner of war, and an Austrian Jew immigrant. The twelve members recorded their time in both theaters and some had later interviews; found footage from the battlefield was paired with the stories of the twelve service members.
The episodes premiered on five consecutive days, with two episodes per day. The series is narrated by Gary Sinise and was produced by Lou Reda Productions in Easton, Pennsylvania, United States.


Tuesday, August 14, 2012

La creación del hombre por Chronos

Source
Explore our timeline of human evolution
Introduction: Human Evolution
by John Pickrell
September 2006
For similar stories, visit the Human Evolution Topic Guide
The incredible story of our evolution from ape ancestors spans 6 million years or more, and features the acquirement of traits from bipedal walkinglarge brainshairlessnesstool-makinghunting and harnessing fire, to the more recent development of languageartculture andcivilisation.
Darwin's The Origin of Species, published in 1859, suggested that humans were descended from African apes. However, no fossils of our ancestors were discovered in Africa until 1924, when Raymond Dart dug up the "Taung child" - a 3-million to 4 million-year-old Australopithecine.
Over the last century, many spectacular discoveries have shed light on the history of the human family. Somewhere between 12 and 19 different species of early humans are recognised, though palaeoanthropologists bitterly dispute how they are related. Famous fossils include the remarkably complete "Lucy", dug up in Ethiopia in 1974, and the astonishing "hobbit" species, Homo floresiensis, found on an Indonesian island in 2004.

Walking tall

Humans are really just a peculiar African ape - we share about 98% of our DNA with chimpanzees, our closest living relatives. Genetics and fossil evidence hint that we last shared a common ancestor 7 to 10 million years ago - even if we continued hybridising long after.
At around 6 million years ago, the first apes to walk on two legs appear in the fossil records. Despite the fact that many of these Australopithecinesand other early humans were no bigger than chimps and had similar-sized brains, the shift to bipedalism was highly significant. Aside from our large brain, bipedalism is perhaps the most important difference between humans and apes, as it freed our hands to use tools.
Bipedalism may have evolved when drier conditions shrank dense African forests. It must have allowed our ancestors to spot predators from further away, reach hanging fruit from the ground, and reduce exposure to sunlight. Evidence that Australopithecines walked upright includes analysis of the shape of their bones and fossilised footprints.
One famous member of the species Australopithecus afarensis is the remarkably complete fossil found by palaeaoanthropologist Donald Johanson in Hadar, Ethiopia in 1974. The 3.2-million-year-old fossil was named Lucy, after the Beatles' song Lucy in the Sky with Diamonds.
She stood around 1.1 metres (3.5 feet) tall and although she walked on two legs, she probably had a less graceful gait than us, since she walked with them bent.
Scientist's have modelled her gait using computers. Their characteristic long arms and curved fingers suggest that at least some Australopithecines were still good climbers.
Hundreds of other fossils of Australopithecus afarensis have now also been discovered. Other related early human species includeAustralopithecus africanus - such as the Taung child - 3.5-million-year-oldKenyanthropus platyops5.8-million to 4.4-million-year-old Ardipithecus, 5.8-million-year-old Orrorin tugenensis and 6 million year oldSahelanthropus tchadensis.

Tooled up

Australopithecines are thought to be the ancestors of Homo, the group to which our own species, Homo sapiens, belongs.
However, Australopithecines may also have given rise to another branch of hominid evolution - the vegetarian Paranthropus species. Around 2.7 million years ago, species such as Paranthropus bosei in east Africa evolved to take advantage of the dry grasslands. This included the development of enormous jaws and chewing muscles for grinding up tough roots and tubers.
By 2.4 million years ago, Homo habilis had appeared - the first recognisably human-like hominid to appear in the fossil record - which lived alongside P. bosei. Their bodies were around two-thirds the size of ours, but their brains were significantly larger than Australopithecines with a volume of about 600 cubic centimetres.
H. habilis had much smaller teeth and jaws than Paranthropus and was probably the first human to eat large quantities of meat. This meaty diet, acquired through scavenging, may have provided energy required to kick-start an increasing brain size. A mutation that weakened jaw muscles and gave our brains more space to grow may also lie behind the big brains we have today.
H. habilis - which means "handy man" - was also the first early human to habitually create tools and use them to break bones and extract marrow. This tool-making tradition, known as Oldowan, lasted virtually unchanged for a million years. Oldowan tools were made by breaking an angular rock with a "hammerstone" to give simple, sharp-edged stone flakes for chopping and slicing.
Despite their own increases in brain size, the Paranthropus group of species had become extinct by 1.2 million years ago. Some experts speculate that it was learning to work as a team against predators that gave Homo the edge.

Modern lookers

At around 1.65 million years ago, another early human, Homo ergaster, started to create tools in a slightly different fashion. This so-calledAcheulean tradition was the tool-making technology used for nearly the entire Stone Age, and practiced until 100,000 years ago. Acheulean tools, such as hand axes and cleavers, were larger and more sophisticated than their predecessors'. They may have been status symbols as well as tools.
Homo ergaster first appeared in Africa around 2 million years ago, and in many ways resembled us. Though they had brow ridges, they had lost the stoop and long arms of their ancestors. They may have been even more slender than us and were probably well-adapted to running long distances. Some experts believe that they were the first to sport largely hairless bodies, and to sweat, though another theory puts our hairlessness down to an aquatic phase.
One famous example of a more modern looking early human is theTurkana boy, a teenager when he died, 1.6 million years ago in Kenya. The shape of this fossil showed that the human pelvis had reached today's narrow proportions. Combined with the growing size of the human head and brain, this had far-reaching implications: human women nowneed help for a successful birth; and human babies are born earlier, and need a longer period of childhood care, than those of apes.
Meat-eating, however, may have allowed us to become early weaners.
H.ergaster may have been the first early human to leave Africa. Bones dated to around 1.75 million years ago have been found in Dmanisi in Georgia.
Shortly afterwards, Homo erectus appeared - the first early human whose fossils have been seen in large numbers outside of Africa. The first specimen discovered, a single cranium, was unearthed in Indonesia in 1891. H.erectus was highly successful, spreading to much of Asiabetween 1.8 and 1.5 million years ago, and surviving as recently as 27,000 years ago.
This species, with a brain volume of around 1000 cm3 would haveinteracted with modern humans. They may have been the first people totake to the seas and habitually hunt prey such as mammoths and wild horses, although there is some debate about this. They may also haveharnessed the use of fire and built the first shelters.
In 2004, the remains of a tiny and mysterious human species, that may have lived as recently as 13,000 years ago, was discovered on an Indonesian island. More bones of the "hobbit", or Homo floresiensis, wereuncovered in 2005. Some studies suggest it had an advanced brain and was unequivocally a separate species - but others argue that these people were modern humans suffering from a genetic disorder.

First Europeans

Early human fossil evidence from Spain, dating to around 780,000 years ago, points to the first known Europeans. Stone tools have also been found in England from around 700,000 years ago, attributed to Homo antecessor or Homo heidelbergensis.
More recently, 325,000-year-old H. heidelbergensis tracks were discovered preserved on an Italian volcano. Some of the biggest collections of hominid remains ever found are from Boxgrove in England and Atapuerca in Spain. Experts believe that these humans may have had ears equipped to detect nuances of human speech, whether or not they had simple language.
Some palaeoanthropologists believe that H. heidelbergensis evolved into our own species in Africa, whilst in Europe, the Neanderthals emerged as a separate species.
The Neanderthals were found across Europe, between 200,000 and 28,000 years ago. Though they still possessed pronounced brow ridges and were more thick-set, these people largely resembled us. They were as nimble-fingered, and matured at a similar age to us. Their brains were even slightly larger. It is not known if the Neanderthals had developedsimple language. But they did possess some aspects of our culture, such as ritual burying of the dead; creating art; using tools to attack each other; and complex hunting methods - as evidenced by a remarkable butchery site in the UK.
Experts disagree about whether the Neanderthals hybridised with humans or not, or if our arrival killed them. Plunging temperaturesfree trade and poor memory may all have contributed towards their extinction.

Out of Africa

There are several competing theories about how all these early humans are related to us today.
Most widely accepted is the "Out of Africa" hypothesis. This holds that ancient humans evolved exclusively in Africa, then spread across the world in two migration waves. The migration of H. erectus across Eurasia made up the first wave. Later, our own species evolved in Africa and fanned out in a second wave 200,000 years ago. These new people totally replaced H. erectus in Asia and the Neanderthals in Europe.
Advocates of the multiregional hypothesis instead believe that early humans started to leave Africa around 2 million years ago, and were never totally replaced by recent migrants. They believe these far-flung hominidsexchanged genes and interbred, slowly evolving into modern humans - in many places, simultaneously. Through gene flow, modern characteristicssuch as large brains gradually spread, it is suggested. Some fossils seem to support the multiregional hypothesis. H. erectus skulls in Asia, for example, have similarly flat cheek and nasal regions as people there today do.
Most - but not all - genetic evidence appears to back the Out of Africa hypothesis. There is surprisingly little variation in the mitochondrial DNA (mDNA) of different people today, which suggest that humans evolved recently from a small ancestral population. In addition, the variation of mDNA in Africans is greater than elsewhere, suggesting that people have been evolving there for longer.
We may all be descended from a single African woman - dubbedMitochondrial Eve - within the last 200,000 years. Male Y-chromosome DNA hints at a single male progenitor, too. Fewer than 50 people could have given rise to the entire population of Europe, experts believe.

Cultural revolution

The earliest anatomically modern humans are though to have arrived around 200,000 years ago. These fossils show a rounded braincase and flatter face. Their brains had reached modern proportions of about 1350 cm3Two skulls found in Ethiopia make up the oldest modern human remains known, at 195,000 years old.
Modern humans had made it to Asia by 90,000 years ago, Australia by60,000 years agoEurope and the Arctic by 40,000 years ago, and the Americas by 12,000 years ago.
Throughout history, tool use appears to have progressed slowly - once innovations were made, they lasted millions of years barely altering. But around 50,000 years ago something changed, and culture started to develop at a much more rapid rate.
Modern humans habitually began innovating new tools types, burying their deadcreating jewellery, developing sophisticated hunting techniques such as pitfall traps, using animal skins for clothing, decorating their bodies, and creating art and cave paintings. Although some of these traits appeared earlier, they seem to have only have been used sporadically until this time.
These changes may have been linked to increasing brain size or the way we thought - or could also be due to free trade, and the evolution oflanguage and communication. The dawn of human civilisation has been dated to around 30,000 years ago. The earliest agriculture and domestication of species is known only as recently as 10,000 years ago. The first human cities appeared in Mesopotamia around 4,000 years ago.
Are we still evolving today? If so, how will we evolve in the future? Some argue that humans have evolved little in the last 50,000 years - but other studies suggests that thousands of genes have changed since then.
We may even be on the verge of the next step of human evolution - the human global "superorganism".

Monday, August 13, 2012

Human sex from the inside out

Source August 2009
from Love and Sex Topic Guide
As should be obvious, the video is sexually explicit.
Don't look anything more! NO sigas mirando!


 by Righty
Why not censor this type of thing. Small children into science might be reading. I can't believe people need to spend funds researching this kind of thing when obviously for 6 billion of us (and growing), reproduction is no problem.

holy shit!!! read all comments


Video: MRI sex
New Scientist brings you sex as you've never seen it before: the first video of a couple having sex in an MRI scanner (see video). Just released, it was made from a series of images captured during an experiment some years ago. The study aimed to prove that it was possible to image male and female genitals during sex and to help better understand human anatomy.