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Acute Epithelial Keratitis
Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology#acute, glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse effects of a substance from a single exposure or in a short period of time Linguistics * Acute accent, a diacritic used in many modern written languages * Acute (phonetic), a perceptual classification See also * Acutance: in photography, a subjective perception of sharpness related to the edgecontrast of an image {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Angle
In Euclidean geometry, an angle is the figure formed by two rays, called the '' sides'' of the angle, sharing a common endpoint, called the ''vertex'' of the angle. Angles formed by two rays lie in the plane that contains the rays. Angles are also formed by the intersection of two planes. These are called dihedral angles. Two intersecting curves may also define an angle, which is the angle of the rays lying tangent to the respective curves at their point of intersection. ''Angle'' is also used to designate the measure of an angle or of a rotation. This measure is the ratio of the length of a circular arc to its radius. In the case of a geometric angle, the arc is centered at the vertex and delimited by the sides. In the case of a rotation, the arc is centered at the center of the rotation and delimited by any other point and its image by the rotation. History and etymology The word ''angle'' comes from the Latin word ''angulus'', meaning "corner"; cognate words are the Greek ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Triangle
An acute triangle (or acute-angled triangle) is a triangle with three acute angles (less than 90°). An obtuse triangle (or obtuse-angled triangle) is a triangle with one obtuse angle (greater than 90°) and two acute angles. Since a triangle's angles must sum to 180° in Euclidean geometry, no Euclidean triangle can have more than one obtuse angle. Acute and obtuse triangles are the two different types of oblique triangles — triangles that are not right triangles because they do not have a 90° angle. Properties In all triangles, the centroid—the intersection of the medians, each of which connects a vertex with the midpoint of the opposite side—and the incenter—the center of the circle that is internally tangent to all three sides—are in the interior of the triangle. However, while the orthocenter and the circumcenter are in an acute triangle's interior, they are exterior to an obtuse triangle. The orthocenter is the intersection point of the triangle's t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Leaf Morphology
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. For more terms describing other aspects of leaves besides their overall morphology see the leaf article. The terms listed here all are supported by technical and professional usage, but they cannot be represented as mandatory or undebatable; readers must use their judgement. Authors often use terms arbitrarily, or coin them to taste, possibly in ignorance of established terms, and it is not always clear whether because of ignorance, or personal preference, or because usages change with time or context, or because of variation between specimens, even specimens from the same plant. For example, whether to call leaves on the same tree "acuminate", "lanceolate", or "linear" could ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute (medicine)
In medicine, describing a disease as acute denotes that it is of short duration and, as a corollary of that, of recent onset. The quantification of how much time constitutes "short" and "recent" varies by disease and by context, but the core denotation of "acute" is always qualitatively in contrast with " chronic", which denotes long-lasting disease (for example, in acute leukaemia and chronic leukaemia). In addition, "acute" also often connotes two other meanings: sudden onset and severity, such as in acute myocardial infarction (AMI), where suddenness and severity are both established aspects of the meaning. It thus often connotes that the condition is fulminant (as in the AMI example), but not always (as in acute rhinitis, which is usually synonymous with the common cold). The one thing that acute MI and acute rhinitis have in common is that they are not chronic. They can happen again (as in recurrent pneumonia, that is, multiple acute pneumonia episodes), but they are not t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Toxicity
Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time (usually less than 24 hours). To be described as ''acute'' toxicity, the adverse effects should occur within 14 days of the administration of the substance. Acute toxicity is distinguished from chronic toxicity, which describes the adverse health effects from repeated exposures, often at lower levels, to a substance over a longer time period (months or years). It is widely considered unethical to use humans as test subjects for acute (or chronic) toxicity research. However, some information can be gained from investigating accidental human exposures (e.g., factory accidents). Otherwise, most acute toxicity data comes from animal testing or, more recently, ''in vitro'' testing methods and inference from data on similar substances. Measures of acute toxicity Regulatory values Limits for short-term exposure, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Accent
The acute accent (), , is a diacritic used in many modern written languages with alphabets based on the Latin, Cyrillic, and Greek scripts. For the most commonly encountered uses of the accent in the Latin and Greek alphabets, precomposed characters are available. Uses History An early precursor of the acute accent was the apex, used in Latin inscriptions to mark long vowels. Pitch Ancient Greek The acute accent was first used in the polytonic orthography of Ancient Greek, where it indicated a syllable with a high pitch. In Modern Greek, a stress accent has replaced the pitch accent, and the acute marks the stressed syllable of a word. The Greek name of the accented syllable was and is (''oxeîa'', Modern Greek ''oxía'') "sharp" or "high", which was calqued (loan-translated) into Latin as "sharpened". Stress The acute accent marks the stressed vowel of a word in several languages: * Blackfoot uses acute accents to show the place of stress in a word: soyópokists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute (phonetic)
In some schools of phonetics, sounds are distinguished as grave or acute. This is primarily a perceptual classification, based on whether the sounds are perceived as sharp, high intensity, or as dull, low intensity. However, it can also be defined acoustically (acute sounds have a concentration of energy in the higher spectrum, versus grave which has a concentration of energy in the lower spectrum) or in terms of the articulations involved. Acute sounds generally have high perceptual intensity, and in the case of consonants have been defined as those with an active articulation involving the tongue and a passive articulation involving anywhere on the roof of the mouth that a coronal articulation can reach, that is, from the to the region. Grave sounds are all other sounds, that is, those involving the lips as either passive or active articulator, or those involving any articulation in the soft palate or throat. Most acute sounds are , and most coronals are acute. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
