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Artificial Sunlight
Artificial sunlight is the use of a light source to simulate sunlight where the unique characteristics of sunlight are needed, but where sufficient natural sunlight is unavailable or infeasible. A device used to simulate sunlight is a solar simulator. Composition of natural sunlight The spectrum of electromagnetic radiation striking the Earth's atmosphere is 100 to 1,000,000 nanometers (nm). This can be divided into five regions in increasing order of wavelengths: * Ultraviolet C (UVC) range: 100–290 nm * Ultraviolet B (UVB) range: 290–320 nm * Ultraviolet A (UVA) range: 320–400 nm * Visible range or light: 400–700 nm * Infrared range. It is further divided into three types on the basis of wavelength: ** Infrared-A: 700–1,400 nm ** Infrared-B: 1,400–3,000 nm ** Infrared-C: 3,000–1,000,000 nm Applications Illumination It has been claimed that artificial light-sources whose spectra most closely mimic the spectrum of terrestrial s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depression (mood)
Depression is a mental state of low Mood (psychology), mood and aversion to activity. It affects about 3.5% of the global population, or about 280 million people worldwide, as of 2020. Depression affects a person's thoughts, behavior, feelings, and subjective well-being, sense of well-being. The pleasure or joy that a person gets from certain experiences is reduced, and the afflicted person often experiences a loss of motivation or interest in those activities. People with depression may experience sadness, feelings of dejection or hopelessness, difficulty in thinking and concentration, or a significant change in appetite or time spent sleeping; Suicidal ideation, suicidal thoughts can also be experienced. Depression can have multiple, sometimes overlapping, origins. Depression can be a symptom of some mood disorders, some of which are also commonly called ''depression'', such as major depressive disorder, bipolar disorder and dysthymia. Additionally, depression can be a norm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Theory
Color theory, or more specifically traditional color theory, is a historical body of knowledge describing the behavior of colors, namely in color mixing, color contrast effects, color harmony, color schemes and color symbolism. Modern color theory is generally referred to as color science. While there is no clear distinction in scope, traditional color theory tends to be more subjective and have artistic applications, while color science tends to be more objective and have functional applications, such as in chemistry, astronomy or color reproduction. Color theory dates back at least as far as Aristotle's treatise ''On Colors'' and Bharata_(sage), Bharata's Natya_Shastra, Nāṭya Shāstra. A formalization of "color theory" began in the 18th century, initially within a partisan controversy over Isaac Newton's theory of color (''Opticks'', 1704) and the nature of primary colors. By the end of the 19th century, a schism had formed between traditional color theory and color science ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microprocessor
A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit (CPU). The IC is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, Clock signal, clock-driven, Processor register, register-based, digital integrated circuit that accepts binary code, binary data as input, processes it according to instruction (computing), instructions stored in its computer memory, memory, and provides results (also in binary form) as output. Microprocessors contain both combinational logic and sequential logic, sequential digital logic, and operate on numbers and symbols represented in the binary number system. The integration of a whole CPU on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Emitting Diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. Later developments produced LEDs available in visible, ultraviolet (UV), an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Carbohydrates
Monosaccharides (from Greek language, Greek ''wikt:μόνος, monos'': single, ''wikt:σάκχαρ, sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built. Chemically, monosaccharides are polyhydroxy aldehydes with the formula or polyhydroxy ketones with the formula with three or more carbon atoms. They are usually Transparency and translucency, colorless, water-soluble, and crystalline organic solids. Contrary to their name (sugars), only some monosaccharides have a sweetness, sweet taste. Most monosaccharides have the formula (CH2O)''x'' (though not all molecules with this formula are monosaccharides). Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose. Monosaccharides are the building blocks of disaccharides (such as sucrose, lactose and maltose) and polysaccharides (such as cellulose and starch). The white sugar, table sugar used in ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyps
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are roughly cylindrical in shape and elongated at the axis of the vase-shaped body. In solitary polyps, the aboral (opposite to oral) end is attached to the substrate by means of a disc-like holdfast called a pedal disc, while in colonies of polyps it is connected to other polyps, either directly or indirectly. The oral end contains the mouth, and is surrounded by a circlet of tentacles. Classes In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species undergoing a life cycle with both a polyp stage and a medusa stage. In the class Scyphozoa, the medusa stage is dominant, and the polyp stage may or may not be present, depending on the family. In those scyphozoans that have the larval planula metamorphose into a polyp, the poly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alga
Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, such as cyanobacteria, '' Chlorella'', and diatoms, to multicellular macroalgae such as kelp or brown algae which may grow up to in length. Most algae are aquatic organisms and lack many of the distinct cell and tissue types, such as stomata, xylem, and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds. In contrast, the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. Algae that are carried passively by water are plankton, specifically phytoplankton. Algae constitute a polyphyletic group because they do not include a common ancestor, and although eukaryotic algae with chlorophyll-bearing plastids seem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zooxanthellae
Zooxanthellae (; zooxanthella) is a colloquial term for single-celled photosynthetic organisms that are able to live in symbiosis with diverse marine invertebrates including corals, jellyfish, demosponges, and nudibranchs. Most known zooxanthellae are in the dinoflagellate genus '' Symbiodinium'', but some are known from the genus '' Amphidinium'', and other taxa, as yet unidentified, may have similar endosymbiont affinities. "Zooxanthella" was originally a genus name (meaning literally "little yellow animal") given in 1881 by Karl Brandt to '' Zooxanthella nutricula'' (a mutualist of the radiolarian '' Collozoum inerme'') which has been placed in the Peridiniales. Another group of unicellular eukaryotes that partake in similar endosymbiotic relationships in both marine and freshwater habitats are green algae zoochlorellae. Zooxanthellae are photosynthetic organisms, which contain chlorophyll a and chlorophyll c, as well as the dinoflagellate pigments peridinin and diadi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiosis
Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biological interaction, between two organisms of different species. The two organisms, termed symbionts, can for example be in Mutualism (biology), mutualistic, commensalism, commensalistic, or parasitism, parasitic relationships. In 1879, Heinrich Anton de Bary defined symbiosis as "the living together of unlike organisms". The term is sometimes more exclusively used in a restricted, mutualistic sense, where both symbionts contribute to each other's subsistence. This means that they benefit each other in some way. Symbiosis can be ''obligate'' (or ''obligative''), which means that one, or both of the organisms depend on each other for survival, or ''facultative'' (optional), when they can also subsist independently. Symbiosis is also classified by physical attachment. Symbionts forming a single body live ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reef Aquarium
A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment. A reef aquarium requires appropriately intense lighting, turbulent water movement, and more stable water chemistry than fish-only marine aquaria, and careful consideration is given to which reef animals are appropriate and compatible with each other. Components Reef aquariums consist of a number of components, in addition to the livestock, including: *Display tank: The primary tank in which the livestock are kept and shown. *Stand: A stand allows for placement of the display tank at eye level and provides space for storage of the accessory components. *Sump: An accessory tank in which mechanical equipment is kept. A remote sump allows for a clutter-free display tank. *Refugium: An accessory tank dedicated to the cultivation of beneficial macroalgae and microflora/fauna. The ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral reef, reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many cloning, genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
