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Diurnal Variation
A chronotype is the behavioral manifestation of 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. The causes and regulation of chronotypes, including developmental change, individual propensity for a specific chronotype, and flexible versus fixed chronotypes have yet to be determined. However, research is beginning to shed light on these questions, such as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment ( entrained by the environment). These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in animals, plants, fungi and cyanobacteria. The term ''circadian'' comes from the Latin '' circa'', meaning "approximately", and ''dies'', 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 circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers (German for "time givers"), which include light, temperature and redox cycles. In clinical settings, an abnormal circadian rhythm in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Distribution
In 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 \mu is the mean or expectation of the distribution (and also its median and mode), while the parameter \sigma is its standard deviation. The variance of the distribution is \sigma^2. 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 converges to a normal dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PER2
PER2 is a protein in mammals encoded by the ''PER2'' gene. ''PER2'' is noted for its major role in circadian rhythms. Discovery The ''per ''gene'' ''was first discovered using forward genetics in '' Drosophilla melanogaster'' in 1971. Mammalian Per2 was discovered by in 1997 through a search for homologous cDNA sequences to PER1. It is more similar to Drosophila ''per'' than its paralogs. Later experiments in also identified ''Per2 ''in humans. Function ''PER2'' is a member of the Period family of genes and is expressed in a circadian pattern in the suprachiasmatic nucleus, the primary circadian pacemaker in the mammalian brain. Genes in this family encode components of the circadian clock, which regulates the daily rhythms of locomotor activity, metabolism, and behavior. Circadian expression of these genes and their encoded proteins in the suprachiasmatic nucleus. Human PER2 is involved in human sleep disorder and cancer formation. Lowered ''PER2'' expression is common in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suprachiasmatic Nucleus
The suprachiasmatic nucleus or nuclei (SCN) is a tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle. The mouse SCN contains approximately 20,000 neurons. The SCN interacts with many other regions of the brain. It contains several cell types and several different peptides (including vasopressin and vasoactive intestinal peptide) and neurotransmitters. Neuroanatomy The SCN is situated in the anterior part of the hypothalamus immediately dorsal, or ''superior'' (hence supra) to the optic chiasm (CHO) bilateral to (on either side of) the third ventricle. The nucleus can be divided into ventrolateral and dorsolateral portions, also known as the core and shell, respectively. These regions differ in their expression of the clock genes, the core expresses them in response to stimuli w ... [...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 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 Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at various locations in the interior of the cell. Adenylate cyclase is ''activated'' by a range of signaling molecules through the activation of adenylate cyclase stimulatory G ( Gs)-protein-coupled receptors. Adenylate cyclase is ''inhibited'' by agonists of adenylate ... [...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'' (α), ''beta'' (β) and ''gamma'' (γ) 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 ar ... [...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 (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b .... 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: rods, 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, sight. Rods primarily mediate scotopic vision (dim conditions) whereas cones primarily mediate to photopic vision (bright conditions), but the processes in each that supports phototransduction is similar. A third class of mammalian photoreceptor cell was disc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome-wide Association Studies
In genomics, a genome-wide association study (GWA study, or GWAS), also known as whole genome association study (WGA study, or WGAS), 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 pers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grit (personality Trait)
In psychology, grit is a positive, non-cognitive trait based on an individual's perseverance of effort combined with the passion for a particular long-term goal or end state (a powerful motivation to achieve an objective). This perseverance of effort promotes the overcoming of obstacles or challenges that lie on the path to accomplishment and serves as a driving force in achievement realization. Distinct but commonly associated concepts within the field of psychology include "perseverance", " hardiness", " resilience", "ambition", " need for achievement" and " conscientiousness". These constructs can be conceptualized as individual differences related to the accomplishment of work rather than talent or ability. This distinction was brought into focus in 1907 when William James challenged the field to further investigate how certain individuals are capable of accessing richer trait reservoirs enabling them to accomplish more than the average person, but the construct dates back at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walterboro, South Carolina
Walterboro is a city in Colleton County, South Carolina, United States. The city's population was 5,398 at the 2010 census. It is the county seat of Colleton County. Walterboro is located west of Charleston and is located near the ACE Basin region in the South Carolina Lowcountry. It is known as ''"The Front Porch of the Lowcountry"''. History Walterboro (original spelling: "''Walterborough''") was founded in 1783, as a summer retreat for local planters looking to escape their malaria-ridden, Lowcountry plantations. The original settlement was located on a hilly area, covered with pine and hickory trees and named "''Hickory Valley''". Two of the earliest settlers were brothers, Paul and Jacob Walter. The brothers were prosperous, plantation owners, in nearby Jacksonboro. Paul's small daughter Mary, was taken ill with malaria; a common disease amongst the families who had plantations in the marshy areas of the Lowcountry, due to the grounds suitability for rice production. To ... [...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 1100 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 r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
