Monday, August 4, 2014
Alpha waves are neural oscillations in the frequency range of 7.5-12.5 Hz arising from synchronous and coherent (in phase or constructive) electrical activity of thalamic pacemaker cells in humans. They are also called Berger's wave in memory of the founder of EEG.
Alpha waves are one type of brain waves detected either by electroencephalography (EEG) or magnetoencephalography (MEG) and predominantly originate from the occipital lobe during wakeful relaxation with closed eyes. Alpha waves are reduced with open eyes, drowsiness and sleep. Historically, they were thought to represent the activity of the visual cortex in an idle state. More recent papers have argued that they inhibit areas of the cortex not in use, or alternatively that they play an active role in network coordination and communication. Occipital alpha waves during periods of eyes closed are the strongest EEG brain signals.
An alpha-like variant called mu (μ) can be found over the motor cortex (central scalp) that is reduced with movement, or the intention to move. Alpha waves do not start to appear until three years of age.
Given the alpha wave's connection with relaxed mental states, many people have latched onto the idea of utilizing this state through a technique called biofeedback training. This technique utilizes EEG to indicate to a subject or trainer when the subject is in an alpha wave state, which the subject is then instructed to remain in.
There are several different prospects of this training that are currently being explored. Arguably, the most popular one is the use of this training in meditation. Zen-trained meditation masters produce noticeably more alpha waves during meditation. This fact has led to a popular trend of biofeedback training programs for everyday stress relief.
Psychologists are hoping to use this technique to help people overcome phobias, calm down hyperactive children, and help children with stuttering problems to relax enough to practice regular speech.
There are other uses of biofeedback training beyond therapy. Defense Department researchers are exploring biofeedback as a way of getting captured soldiers to create alpha waves, potentially foiling enemy lie detectors. Biofeedback training has also been receiving attention as a possible way of monitoring attention. It has been theorized that teaching machines could use biofeedback as a way of monitoring children's attention, with the appearance of alpha waves signaling a lapse of attention.
Following this lapse-of-attention line of thought, a recent study indicates that alpha waves may be used to predict mistakes. In it, MEGs measured increases of up to 25% in alpha brain wave activity before mistakes occurred. This study used common sense: alpha waves indicate idleness, and mistakes are often made when a person is doing something automatically, or "on auto-pilot", and not paying attention to the task they are performing. After the mistake was noticed by the subject, there was a decrease in alpha waves as the subject began paying more attention. This study hopes to promote the use of wireless EEG technology on employees in high-risk fields, such as air traffic controlling, to monitor alpha wave activity and gauge the attention level of the employee.
Alpha waves for restoration and concentracion
Posted by Dune at 2:15 AM
Saturday, August 2, 2014
Tibet (/; Tibetan: བོད་, Wylie: Bod, pronounced [pʰø̀ʔ]; simplified Chinese: 藏区; traditional Chinese: 藏區; pinyin: Zàngqū; Mongolian: Tuvd, also Tsast meaning Snowy) is a plateau region in Asia, north-east of the Himalayas, in the People's Republic of China. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people. Tibet is the highest region on Earth, with an average elevation of 4,900 metres (16,000 ft).
Tibet emerged in the 7th century as a unified empire, but it soon divided into a variety of territories. The bulk of western and central Tibet (Ü-Tsang) was often at least nominally unified under a series of Tibetan governments in Lhasa, Shigatse, or nearby locations; these governments were at various times under Mongol and Chinese overlordship. The eastern regions of Kham and Amdo often maintained a more decentralized indigenous political structure, being divided among a number of small principalities and tribal groups, while also often falling more directly under Chinese rule; most of this area was eventually incorporated into the Chinese provinces of Sichuan and Qinghai. The current borders of Tibet were generally established in the 18th century.
Following the collapse of the Qing dynasty in 1912, Qing soldiers were disarmed and escorted out of Tibet Area (Ü-Tsang). The region subsequently declared its independence in 1913, without recognition by the following Chinese Republican government. Later Lhasa took control of the western part of Xikang Province, China. The region maintained its autonomy until 1951 when, following the Invasion of Tibet, Tibet became unified into the People's Republic of China, and the previous Tibetan government was abolished in 1959 after a failed uprising. Today, the P.R. China governs western and central Tibet as the Tibet Autonomous Region; while eastern areas are mostly within Sichuan, Qinghai and other neighbouring provinces, as ethnic autonomous prefectures. There are tensions regarding Tibet's political status and dissident groups which are active in exile. It is also said that Tibetan activists in Tibet have been arrested or tortured.
The economy of Tibet is dominated by subsistence agriculture, though tourism has become a growing industry in Tibet in recent decades. The dominant religion in Tibet is Tibetan Buddhism, in addition there is Bön which was the indigenous religion of Tibet before the arrival of Buddhism in the 7th century CE (Bön is now similar to Tibetan Buddhism) though there are also Muslim and Christian minorities. Tibetan Buddhism is a primary influence on the art, music, and festivals of the region. Tibetan architecture reflects Chinese and Indian influences. Staple foods in Tibet are roasted barley, yak meat, and butter tea.
Posted by Dune at 5:23 AM
Friday, August 1, 2014
Color or colour (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, blue, yellow, green and others. Color derives from the spectrum of light (distribution of light power versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space, colors can be identified numerically by their coordinates.
Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance.
The science of color is sometimes called chromatics, chromatography, colorimetry, or simply color science. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as light).
Electromagnetic radiation is characterized by its wavelength (or frequency) and its intensity. When the wavelength is within the visible spectrum (the range of wavelengths humans can perceive, approximately from 390 nm to 700 nm), it is known as "visible light".
Most light sources emit light at many different wavelengths; a source's spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, there are many more possible spectral combinations than color sensations. In fact, one may formally define a color as a class of spectra that give rise to the same color sensation, although such classes would vary widely among different species, and to a lesser extent among individuals within the same species. In each such class the members are called metamers of the color in question.
Posted by Dune at 1:45 AM