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Heart Arrhythmia
Heart arrhythmia (also known as arrhythmia, dysrhythmia, or irregular heartbeat) is a group of conditions in which the heartbeat is irregular, too fast, or too slow. A heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia and a heart rate that is too slow – below 60 beats per minute – is called bradycardia. Many types of arrhythmia have no symptoms. When symptoms are present these may include palpitations or feeling a pause between heartbeats. In more serious cases there may be lightheadedness, passing out, shortness of breath, or chest pain. While most types of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in cardiac arrest. There are four main types of arrhythmia: extra beats, supraventricular tachycardias, ventricular arrhythmias, and bradyarrhythmias. Extra beats include premature atrial contractions, premature ventricular contractions, and premature junctional contractions. Supraventricular tachycardias include atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. Ventricular arrhythmias include ventricular fibrillation and ventricular tachycardia. Arrhythmias are due to problems with the electrical conduction system of the heart. Arrhythmias may occur in children; however, the normal range for the heart rate is different and depends on age. A number of tests can help with diagnosis including an electrocardiogram (ECG) and Holter monitor. Most arrhythmias can be effectively treated. Treatments may include medications, medical procedures such as inserting a pacemaker, and surgery. Medications for a fast heart rate may include beta blockers or agents that attempt to restore a normal heart rhythm such as procainamide. This latter group may have more significant side effects especially if taken for a long period of time. Pacemakers are often used for slow heart rates. Those with an irregular heartbeat are often treated with blood thinners to reduce the risk of complications. Those who have severe symptoms from an arrhythmia may receive urgent treatment with a controlled electric shock in the form of cardioversion or defibrillation. Arrhythmia affects millions of people. In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population. Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990. Sudden cardiac death is the cause of about half of deaths due to cardiovascular disease or about 15% of all deaths globally. About 80% of sudden cardiac death is the result of ventricular arrhythmias. Arrhythmias may occur at any age but are more common among older people.
  • 963
  • 08 Oct 2022
Topic Review
TPT
TPT (time partition testing) is a systematic test methodology for the automated software test and verification of embedded control systems, cyber-physical systems, and dataflow programs. TPT is specialised on testing and validation of embedded systems whose inputs and outputs can be represented as signals and is a dedicated method for testing continuous behaviour of systems. Most control systems belong to this system class. The outstanding characteristic of control systems is the fact that they interact closely interlinked with a real world environment. Controllers need to observe their environment and react correspondingly to its behaviour. The system works in an interactional cycle with its environment and is subject to temporal constraints. Testing these systems is to stimulate and to check the timing behaviour. Traditional functional testing methods use scripts – TPT uses model-based testing. TPT combines a systematic and graphic modelling technique for test cases with a fully automated test execution in different environments and automatic test evaluation. TPT covers the following four test activities:
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  • 08 Oct 2022
Topic Review
Kerala School of Astronomy and Mathematics
The Kerala School of Astronomy and Mathematics was a school of mathematics and astronomy founded by Madhava of Sangamagrama in Kerala, India, which included among its members: Parameshvara, Neelakanta Somayaji, Jyeshtadeva, Achyuta Pisharati, Melpathur Narayana Bhattathiri and Achyuta Panikkar. The school flourished between the 14th and 16th centuries and the original discoveries of the school seems to have ended with Narayana Bhattathiri (1559–1632). In attempting to solve astronomical problems, the Kerala school independently discovered a number of important mathematical concepts. Their most important results—series expansion for trigonometric functions—were described in Sanskrit verse in a book by Neelakanta called Tantrasangraha, and again in a commentary on this work, called Tantrasangraha-vakhya, of unknown authorship. The theorems were stated without proof, but proofs for the series for sine, cosine, and inverse tangent were provided a century later in the work Yuktibhasa (c. 1500 – c. 1610), written in Malayalam, by Jyesthadeva, and also in a commentary on Tantrasangraha. Their work, completed two centuries before the invention of calculus in Europe, provided what is now considered the first example of a power series (apart from geometric series). However, they did not formulate a systematic theory of differentiation and integration, nor is there any direct evidence of their results being transmitted outside Kerala.
  • 4.1K
  • 07 Oct 2022
Topic Review
Aurora A Kinase
Aurora kinase A also known as serine/threonine-protein kinase 6 is an enzyme that in humans is encoded by the AURKA gene. Aurora A is a member of a family of mitotic serine/threonine kinases. It is implicated with important processes during mitosis and meiosis whose proper function is integral for healthy cell proliferation. Aurora A is activated by one or more phosphorylations and its activity peaks during the G2 phase to M phase transition in the cell cycle.
  • 694
  • 07 Oct 2022
Topic Review
Rudolf Carnap
Rudolf Carnap (/ˈkɑːrnæp/; German: [ˈkaʁnaːp]; 18 May 1891 – 14 September 1970) was a German-language philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism. He is considered "one of the giants among twentieth-century philosophers."
  • 2.8K
  • 24 Nov 2022
Topic Review
List of Minerals U–V (Complete)
This list includes those recognised minerals beginning with the letters U and V. The International Mineralogical Association is the international group that recognises new minerals and new mineral names, however minerals discovered before 1959 did not go through the official naming procedure, although some minerals published previously have been either confirmed or discredited since that date. This list contains a mixture of mineral names that have been approved since 1959 and those mineral names believed to still refer to valid mineral species (these are called "grandfathered" species). The list is divided into groups: The data was exported from mindat.org on 29 April 2005; updated up to 'IMA2018'. The minerals are sorted by name, followed by the structural group (rruff.info/ima and ima-cnmnc by mineralienatlas.de, mainly) or chemical class (mindat.org and basics), the year of publication (if it's before of an IMA approval procedure), the IMA approval and the Nickel–Strunz code. The first link is to mindat.org, the second link is to webmineral.com, and the third is to the Handbook of Mineralogy (Mineralogical Society of America).
  • 3.2K
  • 07 Oct 2022
Topic Review
Cartography of Jerusalem
The cartography of Jerusalem is the creation, editing, processing and printing of maps of Jerusalem from ancient times until the rise of modern surveying techniques. Almost all extant maps known to scholars from the pre-modern era were prepared by Christian mapmakers for a Christian European audience. Maps of Jerusalem can be categorized between original factual maps, copied maps and imaginary maps, the latter being based on religious books. The maps were produced in a variety of materials, including parchment, vellum, mosaic, wall paintings and paper. All maps marking milestones in the cartography of Jerusalem are listed here following the cartographic histories of the city, from Titus Tobler and Reinhold Röhricht's studies in the 19th century to those of Hebrew University of Jerusalem academics Rehav Rubin and Milka Levy-Rubin in recent decades. The article lists maps that progressed the cartography of Jerusalem before the rise of modern surveying techniques, showing how mapmaking and surveying improved and helped outsiders to better understand the geography of the city. Imaginary maps of the ancient city and copies of existing maps are excluded. The Madaba Map is the oldest known map of Jerusalem, in the form of a mosaic in a Greek Orthodox Church. At least 12 maps survive from the Catholic mapmakers of the Crusades; they were drawn on vellum and mostly show the city as a circle. The first printed map of the city was drawn by Erhard Reuwich and published in 1486 by Bernhard von Breydenbach in his Peregrinatio in Terram Sanctam, based on his pilgrimage of 1483. Approximately 500 maps are known between the late-1400s and the mid-1800s; the significant increase in number is due to the advent of the printing press. Few of the mapmakers had travelled to Jerusalem – most of the maps were either copies of others' maps or were imaginary (i.e. based on reading of religious texts) in nature. The first map based on actual field measurements was published in 1818 by the Czech mapmaker Franz Wilhelm Sieber. The first map based on modern surveying techniques was published by Charles Wilson of the Palestine Exploration Fund in 1864–65, who produced two maps for the British Ordnance Survey.
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  • 07 Oct 2022
Topic Review
Waveguide (Electromagnetism)
In electromagnetics and communications engineering, the term waveguide may refer to any linear structure that conveys electromagnetic waves between its endpoints. However, the original and most common meaning is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission line mostly at microwave frequencies, for such purposes as connecting microwave transmitters and receivers to their antennas, in equipment such as microwave ovens, radar sets, satellite communications, and microwave radio links. A dielectric waveguide employs a solid dielectric rod rather than a hollow pipe. An optical fibre is a dielectric guide designed to work at optical frequencies. Transmission lines such as microstrip, coplanar waveguide, stripline or coaxial cable may also be considered to be waveguides. The electromagnetic waves in a (metal-pipe) waveguide may be imagined as travelling down the guide in a zig-zag path, being repeatedly reflected between opposite walls of the guide. For the particular case of rectangular waveguide, it is possible to base an exact analysis on this view. Propagation in a dielectric waveguide may be viewed in the same way, with the waves confined to the dielectric by total internal reflection at its surface. Some structures, such as non-radiative dielectric waveguides and the Goubau line, use both metal walls and dielectric surfaces to confine the wave.
  • 4.4K
  • 07 Oct 2022
Topic Review
Wages in Thailand
Wages in Thailand, as used here, includes all compensation paid by an employer to an employee for work done, whether based on hours worked, piece work, or fixed salary. Since wage labour is the predominant form of work, the term "wage" here refers to all forms of employee compensation. Wages are the major source of household income in Thailand,:32 although wage income distribution varies by region: Almost three-quarters of the population in Bangkok are in households that receive wage income, compared with less than half in the northern region.:30-31 During the period 2007–2014, wage income grew markedly, and then began to drop starting in 2015. (As of 2020) wage growth stagnation afflicts most occupations. Wage growth was negative in urban areas, but positive in rural areas. In the period 2007–2013, wages, farm incomes, and remittances contributed to poverty reduction; in the period 2015–2017 these were sources of rising poverty.:65
  • 26.0K
  • 07 Oct 2022
Topic Review
Wink
A wink is a facial expression made by briefly closing one eye. A wink is an informal mode of non-verbal communication usually signaling shared hidden knowledge or intent. However, it is ambiguous by itself and highly dependent upon additional context, without which a wink could become misinterpreted or even nonsensical. For example, in some regions of the world, a wink may be considered rude or offensive. And depending on the relationship of the people involved, a wink could possibly constitute a sexual gesture.
  • 2.9K
  • 07 Oct 2022
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