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Diurnal Variation
A chronotype is the behavioral manifestation of an underlying circadian rhythm's myriad of physical processes. A person's chronotype is the propensity for the individual to sleep at a particular time during a 24-hour period. ''Eveningness'' (delayed sleep period; most active and alert in the evening) and ''morningness'' (advanced sleep period; most active and alert in the morning) are the two extremes with most individuals having some flexibility in the timing of their sleep period. However, across development there are changes in the propensity of the sleep period with pre-pubescent children preferring an advanced sleep period, adolescents preferring a delayed sleep period and many elderly preferring an advanced sleep period. Humans are normally diurnal creatures that are active in the daytime. As with most other diurnal animals, human activity-rest patterns are endogenously regulated by biological clocks with a circadian (~24-hour) period. Chronotypes have also been investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the environment (is Entrainment (chronobiology), entrained by the environment). Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximize the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life. The term ''circadian'' comes from the Latin ', meaning "around", and ', meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Distribution
In probability theory and statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is f(x) = \frac e^\,. The parameter is the mean or expectation of the distribution (and also its median and mode), while the parameter \sigma^2 is the variance. The standard deviation of the distribution is (sigma). A random variable with a Gaussian distribution is said to be normally distributed, and is called a normal deviate. Normal distributions are important in statistics and are often used in the natural and social sciences to represent real-valued random variables whose distributions are not known. Their importance is partly due to the central limit theorem. It states that, under some conditions, the average of many samples (observations) of a random variable with finite mean and variance is itself a random variable—whose distribution c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suprachiasmatic Nucleus
The suprachiasmatic nucleus or nuclei (SCN) is a small region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for regulating sleep cycles in animals. Reception of light inputs from photosensitive retinal ganglion cells allow it to coordinate the subordinate cellular clocks of the body and entrain to the environment. The neuronal and hormonal activities it generates regulate many different body functions in an approximately 24-hour cycle. The SCN also interacts with many other regions of the brain. It contains several cell types, neurotransmitters and peptides, including vasopressin and vasoactive intestinal peptide. Disruptions or damage to the SCN has been associated with different mood disorders and sleep disorders, suggesting the significance of the SCN in regulating circadian timing. Neuroanatomy The SCN is situated in the anterior part of the hypothalamus immediately dorsal, or ''superior'' (hence supra) to the optic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Adenosine Monophosphate
Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger, or cellular signal occurring within cells, that is important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms, conveying the cAMP-dependent pathway. History Earl Sutherland of Vanderbilt University won a Nobel Prize in Physiology or Medicine in 1971 "for his discoveries concerning the mechanisms of the action of hormones", especially epinephrine, via second messengers (such as cyclic adenosine monophosphate, cyclic AMP). Synthesis The synthesis of cAMP is stimulated by trophic hormones that bind to receptors on the cell surface. cAMP levels reach maximal levels within minutes and decrease gradually over an hour in cultured cells. Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-protein
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their activity is regulated by factors that control their ability to bind to and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP). When they are bound to GTP, they are 'on', and, when they are bound to GDP, they are 'off'. G proteins belong to the larger group of enzymes called GTPases. There are two classes of G proteins. The first function as monomeric small GTPases (small G-proteins), while the second function as heterotrimeric G protein complexes. The latter class of complexes is made up of ''alpha'' (Gα), ''beta'' (Gβ) and ''gamma'' (Gγ) subunits. In addition, the beta and gamma subunits can form a stable dimeric complex referred to as the beta-gamma complex . Heterotrimeric G proteins located within the cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGS16
Regulator of G-protein signaling 16 is a protein that in humans is encoded by the ''RGS16'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei .... Function The protein encoded by this gene belongs to the 'regulator of G protein signaling' family. It inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits. It also may play a role in regulating the kinetics of signaling in the phototransduction cascade. Interactions RGS16 has been shown to interact with GNAQ and GNAI3. References Further reading * * * * * * * * * * * * * * * * * * * * * * * * * {{PDB Gallery, geneid=6004 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoreceptor Cell
A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential. There are currently three known types of photoreceptor cells in mammalian eyes: rod cell, rods, cone cell, cones, and intrinsically photosensitive retinal ganglion cells. The two classic photoreceptor cells are rods and cones, each contributing information used by the visual system to form an image of the environment, Visual perception, sight. Rods primarily mediate scotopic vision (dim conditions) whereas cones primarily mediate photopic vision (bright conditions), but the processes in each that supports phototransduction is similar. The intrinsically photosen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome-wide Association Studies
In genomics, a genome-wide association study (GWA study, or GWAS), is an observational study of a genome-wide set of genetic variants in different individuals to see if any variant is associated with a trait. GWA studies typically focus on associations between single-nucleotide polymorphisms (SNPs) and traits like major human diseases, but can equally be applied to any other genetic variants and any other organisms. When applied to human data, GWA studies compare the DNA of participants having varying phenotypes for a particular trait or disease. These participants may be people with a disease (cases) and similar people without the disease (controls), or they may be people with different phenotypes for a particular trait, for example blood pressure. This approach is known as phenotype-first, in which the participants are classified first by their clinical manifestation(s), as opposed to genotype-first. Each person gives a sample of DNA, from which millions of genetic variant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glare (vision)
Glare is difficulty of seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night. Because of this, some cars include mirrors with automatic anti-glare functions and in buildings, blinds or louvers are often used to protect occupants. Glare is caused by a significant ratio of luminance between the task (that which is being looked at) and the glare source. Factors such as the angle between the task and the glare source and eye adaptation have significant impacts on the experience of glare. Discomfort and disability Glare can be generally divided into two types, discomfort glare and disability glare. Discomfort glare is a psychological sensation caused by high brightness (or brightness contrast) within the field of view, which does not necessarily impair vision. In buildings, discomfort glare can originate from small artificial lights (e.g. ceiling fixtures) that have brightnesses that are significantly greater tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grit (personality Trait)
In psychology, grit is a positive, non-cognitive trait based on a person's perseverance of effort combined with their passion for a particular long-term goal or end state (a powerful motivation to achieve an objective). This perseverance of effort helps people overcome obstacles or challenges to accomplishment and drives people to achieve. Distinct but commonly associated concepts within the field of psychology include ''perseverance'', '' hardiness'', '' resilience'', '' ambition'', '' need for achievement'', ''conscientiousness'', and '' tenacity''. These constructs can be conceptualized as individual differences related to the accomplishment of work rather than as talent or ability. This distinction was brought into focus in 1907 when William James challenged psychology to further investigate how certain people can access richer trait reservoirs that enable them to accomplish more than the average person. However, the construct of grit dates back at least to Francis Galton, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walterboro, South Carolina
Walterboro is a city in Colleton County, South Carolina, Colleton County, South Carolina, United States. The city's population was 5,398 at the 2010 United States Census, 2010 census. It is the county seat of Colleton County. Walterboro is located west of Charleston, South Carolina, Charleston and is located near the ACE Basin region in the South Carolina Lowcountry. History Walterboro (original spelling: Walterborough) was founded in 1783, as a summer retreat for local planters looking to escape their malaria-ridden, South Carolina Lowcountry, Lowcountry plantations in the American South, plantations. The original settlement was located on a hilly area, covered with pine and hickory trees and called Hickory Valley. Two of the earliest settlers were brothers, Paul and Jacob Walter. The brothers were prosperous, plantation owners, in nearby Jacksonboro, South Carolina, Jacksonboro. Paul's small daughter Mary, was taken ill with malaria; a common disease among the families who had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of South Carolina Salkehatchie
The University of South Carolina Salkehatchie (USC Salkehatchie) is a public college with campuses in Allendale and Walterboro, South Carolina. It is one of four regional University of South Carolina System campuses which make up Palmetto College. USC Salkehatchie is accredited by the Southern Association of Colleges and Schools as part of the flagship campus ( University of South Carolina Columbia). More than 1,100 students attend at one of its two sites. History The citizens of Allendale, Bamberg, and Hampton counties led an effort in 1964 to establish a center of higher education for their region of South Carolina. The proposal was warmly received by the General Assembly, and the Western Carolina Higher Education Commission was created to investigate the possibility of a college for the region. House Speaker Solomon Blatt pleaded with the University of South Carolina to build two-year colleges across the state so as to prevent any possible expansion by Clemson. As a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
