Camellia
Distemper paints on paper
Monday, August 4, 2014
Alpha waves
Alpha waves
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.
Biofeedback training
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
Saturday, August 2, 2014
Tibet
Tibet
Tibet
(tɨˈbɛt/;
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.
Friday, August 1, 2014
Color
Color
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.
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