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Asymmetries
Asymmetry is the absence of, or a violation of, symmetry (the property of an object being invariant to a transformation, such as reflection). Symmetry is an important property of both physical and abstract systems and it may be displayed in precise terms or in more aesthetic terms. The absence of or violation of symmetry that are either expected or desired can have important consequences for a system. In organisms Due to how cells divide in organisms, asymmetry in organisms is fairly usual in at least one dimension, with biological symmetry also being common in at least one dimension. Louis Pasteur proposed that biological molecules are asymmetric because the cosmic .e. physicalforces that preside over their formation are themselves asymmetric. While at his time, and even now, the symmetry of physical processes are highlighted, it is known that there are fundamental physical asymmetries, starting with time. Asymmetry in biology Asymmetry is an important and widespread t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facial Symmetry
Facial symmetry is one specific measure of bodily symmetry. Along with traits such as averageness and youthfulness it influences judgments of aesthetic traits of physical attractiveness and beauty. For instance, in mate selection, people have been shown to have a preference for symmetry. Facial bilateral symmetry is typically defined as fluctuating asymmetry of the face comparing random differences in facial features of the two sides of the face. The human face also has systematic, directional asymmetry: on average, the face (mouth, nose and eyes) sits systematically to the left with respect to the axis through the ears, the so-called ''aurofacial asymmetry''. Directional asymmetry Directional asymmetry is a systematic asymmetry of some parts of the face across the population. A theory of directional asymmetries in the human body is the axial twist hypothesis. As predicted by this theory, the eyes, nose and mouth are, on average, located slightly to the left of the axis throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handedness
In human biology, handedness is an individual's preferential use of one hand, known as the dominant hand, due to it being stronger, faster or more Fine motor skill, dextrous. The other hand, comparatively often the weaker, less dextrous or simply less subjectively preferred, is called the non-dominant hand. In a study from 1975 on 7688 children in US grades 1-6, Left handers comprised 9.6% of the sample, with 10.5% of male children and 8.7% of female children being left-handed. Handedness is often defined by one's writing hand, as it is fairly common for people to prefer to do some tasks with each hand. There are examples of true ambidexterity (equal preference of either hand), but it is rare—most people prefer using one hand for most purposes. Most of the current research suggests that left-handedness has an epigenetic marker—a combination of genetics, biology and the environment. Because the vast majority of the population is right-handed, many devices are designed for u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetry (biology)
Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a plane of symmetry down its centre, or a pine cone with a clear symmetrical spiral pattern. Internal features can also show symmetry, for example the tubes in the human body (responsible for transporting gases, nutrients, and waste products) which are cylindrical and have several planes of symmetry. Biological symmetry can be thought of as a balanced distribution of duplicate body parts or shapes within the body of an organism. Importantly, unlike in mathematics, symmetry in biology is always approximate. For example, plant leaves – while considered symmetrical – rarely match up exactly when folded in half. Symmetry is one class of patterns in nature whereby there is near-repetition of the pattern element, either by reflection or rotation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left-right Asymmetry (biology)
Left-right asymmetry, (LR asymmetry) is the process in early embryonic development that breaks the normal symmetry in the bilateral embryo. In vertebrates, left-right asymmetry is established early in development at a structure called the left-right organizer (the name of which varies between species) and leads to activation of different signalling pathways on the left and right of the embryo. This in turn cause several organs in adults to develop LR asymmetry, such as the tilt of the heart, the different number lung lobes on each side of the body and the position of the stomach and spleen on the right side of the body. If this process does not occur correctly in humans it can result in the syndromes heterotaxy or situs inversus. LR asymmetry is pervasive throughout all animals, including invertebrates. Examples of invertebrate LR asymmetry include the large and small claws of the fiddler crab, asymmetrical gut coiling in ''Drosophila melanogaster,'' and dextral (clockwise) and si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passive Fire Protection
Passive fire protection (PFP) is components or systems of a building or structure that slows or impedes the spread of the effects of fire or smoke without system activation, and usually without movement. Examples of passive systems include floor-ceilings and roofs, fire doors, windows, and wall assemblies, fire-resistant coatings, and other fire and smoke control assemblies. Passive fire protection systems can include active components such as fire dampers. Main characteristics Passive fire protection systems are intended to: * Contain a fire to the compartment of fire origin * Slow a fire from spreading from the compartment of fire origin * Slow the heating of structural members * Prevent the spread of fire through intentional openings (e.g., doors, HVAC ducts) in fire rated assemblies by the use of a fire rated closure (e.g., fire door, fire damper) * Prevent the spread of fire through penetrations (e.g., holes in fire walls through which building systems such as plumbing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire-resistance Rating
A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail other criteria, involving evidence of functionality or fitness for purpose. Common rating systems The following depict the most commonly used international time/temperature curves: File:Din iso astm ul curves.JPG, Time/Temperature Curves used for testing the fire-resistance rating of passive fire protection systems such as firestops, fire doors, wall and floor assemblies, etc., which are used in compartmentalisation in buildings and the petrochemical industry in Europe and North America. File:Tunnel hc iso curves.jpg, Time/Temperature Curves used for testing the fire-resistance rating of passive fire protection systems in tunnels in Germany, The Netherlands and France. File:Rws tunnel curve.jpg, Time/Temperature Curve used for testing the fire-resistance rating of pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outrigger Canoe
Outrigger boats are various watercraft featuring one or more lateral support floats known as outriggers, which are fastened to one or both sides of the main hull. They can range from small dugout canoes to large plank-built vessels. Outrigger boats can also vary in their configuration, from the ancestral double-hull configuration (catamarans), to single-outrigger vessels prevalent in the Pacific Islands and Madagascar, to the double-outrigger vessels (trimarans) prevalent in Island Southeast Asia. They are traditionally fitted with Austronesian sails, like the crab claw sails and tanja sails, but in modern times are often fitted with petrol engines. Unlike a single-hulled vessel, an outrigger or double-hull vessel generates stability as a result of the distance between its hulls rather than due to the shape of each individual hull. As such, the hulls of outrigger or double-hull boats are typically longer, narrower and more hydrodynamically efficient than those of single-hul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proa
Proas are various types of multi-hull outrigger sailboats of the Austronesian peoples. The terms were used for native Austronesian ships in European records during the Colonial era indiscriminately, and thus can confusingly refer to the double-ended single-outrigger boats of Oceania, the double-outrigger boats of Island Southeast Asia, and sometimes ships with no outriggers or sails at all. In its most common usage, the term ''proa'' refers to the Pacific proas which consist of two (usually) unequal-length parallel hulls. It is sailed so that one hull is kept to windward, and the other to leeward. It is double-ended, since it needs to " shunt" to reverse direction when tacking. It is most famously used for the ''sakman'' ships of the Chamorro people of the Northern Marianas, which were known as the "flying proas" for their remarkable speed. In Island Southeast Asia, the term ''proa'' may also sometimes be used, but the terms perahu, prau, prahu, paraw and prow are more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blohm & Voss BV 141
The Blohm & Voss BV 141 was a World War II German tactical reconnaissance aircraft, notable for its uncommon structural asymmetry. Although the Blohm & Voss BV 141 performed well, it was never ordered into full-scale production, for reasons that included the unavailability of the preferred engine and competition from another tactical reconnaissance aircraft, the Focke-Wulf Fw 189. Development In 1937, the German Air Ministry – the ''Reichsluftfahrtministerium'' (RLM) – issued a specification for a single-engine reconnaissance aircraft with optimal visual characteristics. The preferred contractor was Arado with the Ar 198, but the prototype proved unsuccessful.. The eventual winner was the Focke-Wulf Fw 189 ''Uhu''; even though its twin-boom design using two smaller engines did not match the requirement of a single engined aircraft. Blohm & Voss ( Hamburger Flugzeugbau) although not invited to participate, pursued as a private venture something far more radical. The proposa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limb (anatomy)
A limb (from the Old English ''lim'', meaning "body part") or leg is a jointed, muscled appendage that tetrapod vertebrates use for weight-bearing and terrestrial locomotion such as walking, running and jumping, for paddle-swimming, or for grasping and climbing. The distalmost portion of a limb is known as its extremity. The limbs' bony endoskeleton, known as the appendicular skeleton, is homologous among all tetrapods. All tetrapods have four limbs that are organized into two bilaterally symmetrical pairs, with one pair at each end of the torso. The cranial pair are known as the forelimbs or ''front legs'', and the caudal pair the hindlimbs or ''back legs''. In animals with more upright posture (mainly hominid primates, particularly humans), the forelimbs and hindlimbs are often called upper and lower limbs, respectively. The fore-/upper limbs are connected to the thoracic cage via the shoulder girdles, and the hind-/lower limbs are connected to the pelvis via the hip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditorio De Tenerife
The Auditorio de Tenerife "Adán Martín" (commonly referred to as the Auditorio de Tenerife) is an auditorium in Santa Cruz de Tenerife, Canary Islands, Spain. Designed by architect Santiago Calatrava, it is located on the Avenue of the Constitution in the Canarian capital, and next to the Atlantic Ocean in the southern part of Port of Santa Cruz de Tenerife. Construction began in 1997 and was completed in 2003. The auditorium was inaugurated on 26 September of that year in the presence of Felipe, Prince of Asturias, and was later visited by former U.S. President Bill Clinton. The building is framed within the tenets of late-modern architecture of the late 20th century. The majestic profile of the auditorium has become an architectural symbol of the city of Santa Cruz de Tenerife, the island of Tenerife and the Canary Islands. It is also regarded as the finest contemporary building in the Canary Islands and one of the most emblematic buildings of Spanish architecture. In March 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puente De La Mujer
The Puente de la Mujer (Spanish for "Woman's Bridge") is a rotating footbridge for Dock 3 of the Puerto Madero commercial district of Buenos Aires, Argentina. It is of the cantilever spar cable-stayed bridge type and is also a swing bridge, but somewhat unusual in its asymmetrical arrangement. It has a single mast with cables suspending a portion of the bridge which rotates 90 degrees in order to allow water traffic to pass. When it swings to allow watercraft passage, the far end comes to a resting point on a stabilizing pylon. History Designed by the Spanish architect and structural engineer Santiago Calatrava on a plan very similar to a 251-metre bridge over the Guadalquivir River in Seville, Spain (1992) and a 213-metre bridge over the Sacramento River in Redding, California (2004), it has a forward-, rather than a reverse-angled cantilever, as is seen in those bridges. Started in 1998, it was inaugurated on December 20, 2001, and is the first of only two Calatrava structures in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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